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Sample records for kcl caoh2 h3po4

  1. Oscillation in the Kmno 4NH 2CH 2COOHH 3PO 4 Cstr system

    NASA Astrophysics Data System (ADS)

    Li, Hexing; Huang, Xiaojun; Deng, Jingfa

    1996-08-01

    A novel chemical oscillating reaction in the KMnO 4NH 2CH 2COOHH 3PO 4 CSTR system in the presence and absence of Ag + has been described. The reaction kinetics in a closed Mn0 4-NH 2CH 2COOHH 3PO 4 system has been analyzed and a possible mechanism has been proposed. The catalytic effect of Ag + in the above reaction has also been studied.

  2. 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

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

    PubMed

    Zhao, Wenxia; Ding, Jie; Wang, Zenglin

    2013-05-21

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

  4. 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.

  5. Fabrication and characterization of mesoporous activated carbon from Lemna minor using one-step H3PO4 activation for Pb(II) removal

    NASA Astrophysics Data System (ADS)

    Huang, Yang; Li, Shunxing; Lin, Haibin; Chen, Jianhua

    2014-10-01

    A low cost and locally available material, Lemna minor, was used to fabricate activated carbon using H3PO4 activation. After H3PO4 activation, the L. minor activated carbons (LACs) possess high mesoporosity (92.2%) and a surface area of 531.9 m2/g according to Brunauer-Emmett-Teller (BET) analysis. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses reveal the presence of rich hydroxyl, carboxyl, amide and phosphate functional groups on the LACs surface, leading to facile Pb(II) binding to the surface through strong chemisorptive bonds or ion-exchange. The kinetic and equilibrium data were well described by pseudo-first-order model and Langmuir isotherm, with the maximum monolayer adsorption capacity (qm) 170.9 mg/g at 25 °C. The intra-particle diffusion mechanism was partially responsible for the adsorption. The adsorption process was spontaneous and endothermic with negative ΔG and positive ΔH. The Pb(II)-loaded LACs could be easily regenerated using 0.1-M HCl and reused for seven cycles without significant adsorption capacity reduction. The maximum percentage removal rate for Pb(II) (20 mg/L) was found to be 91.8% within 30 min, at optimum conditions of pH 6.0 and 25 °C. These suggested that the low-cost LACs could be used as a potential adsorbent in the treatment of lead-contaminated water.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. Quantification of competing H3PO4 versus HPO3 + H2O neutral losses from regioselective 18O-labeled phosphopeptides.

    PubMed

    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-MS(3) 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 (18)O-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 (18)O) 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.

  11. 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.

  12. Determination of traces of chloride and fluoride in H2SO4, H3PO4 and H3BO3 by in situ analyte distillation-ion chromatography.

    PubMed

    Thangavel, S; Dash, K; Dhavile, S M; Chaurasia, S C; Mukherjee, T

    2005-05-13

    A simple dual vessel in situ analyte distillation (IAD) system has been developed for suppressed ion chromatographic determination of chloride and fluoride ions in complex matrices. In IAD system, water vapours generated from the outer vessel reacts with sulfuric acid generating heat, thus favouring the quantitative distillation of chloride and fluoride within 30 min on water bath temperature (approximately 80 degrees C). The distilled analytes, as their respective acids in water, were directly injected into an ion-chromatograph. This newly developed method has been applied for analysis of trace impurities in H2SO4, H3PO4 and H3BO3. The detection limits for chloride is 8, 80 and 70ppb (w/w) for H2SO4, H3PO4 and H3BO3, respectively. For fluoride the detection limits are 6 and 60 ppb (w/w) for H2SO4 and H3PO4, respectively. The recovery of spikes for both the analytes ranged between 87 and 100%.

  13. 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

  14. A comparative study of Pt/C cathodes in Sn 0.9In 0.1P 2O 7 and H 3PO 4 ionomers for high-temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Jin, Y. C.; Okada, M.; Hibino, T.

    New Pt/C cathodes with many reaction sites for the oxygen reduction reaction as well as high tolerance to Pt corrosion have been designed for high-temperature proton exchange membrane fuel cells (PEMFCs), wherein a composite mixture of Sn 0.9In 0.1P 2O 7 (SIPO) and sulfonated polystyrene-b-poly(ethylene/butylene)-b-polystyrene (sSEBS) functioned as an ionomer. The microstructure of the Pt-SIPO-sSEBS/C cathode was characterized by homogeneous distribution of the ionomer over the catalyst layer and close contact between the ionomer and the Pt/C powder. As a result, the activation and concentration overpotentials of the Pt-SIPO-sSEBS/C cathode between 100 and 200 °C were lower than those of an H 3PO 4-impregnated Pt/C cathode, which suggests that the present ionomer can avoid poisoning of Pt by phosphate anions and the limitation of gas diffusion through the catalyst layer. Moreover, agglomeration of Pt in the Pt-SIPO-sSEBS/C cathode was not observed during a durability test at 150 °C for 6 days, although it was significant in the Pt-H 3PO 4/C cathode. Therefore, it is concluded that the Pt-SIPO-sSEBS/C electrode is a very promising cathode candidate for high-temperature PEMFCs.

  15. A comparative study of nano-SiO2 and nano-TiO2 fillers on proton conductivity and dielectric response of a silicotungstic acid-H3PO4-poly(vinyl alcohol) polymer electrolyte.

    PubMed

    Gao, Han; Lian, Keryn

    2014-01-01

    The effects of nano-SiO2 and nano-TiO2 fillers on a thin film silicotungstic acid (SiWA)-H3PO4-poly(vinyl alcohol) (PVA) proton conducting polymer electrolyte were studied and compared with respect to their proton conductivity, environmental stability, and dielectric properties, across a temperature range from 243 to 323 K. Three major effects of these fillers have been identified: (a) barrier effect; (b) intrinsic dielectric constant effect; and (c) water retention effect. Dielectric analyses were used to differentiate these effects on polymer electrolyte-enabled capacitors. Capacitor performance was correlated to electrolyte properties through dielectric constant and dielectric loss spectra. Using a single-ion approach, proton density and proton mobility of each polymer electrolyte were derived as a function of temperature. The results allow us to deconvolute the different contributions to proton conductivity in SiWA-H3PO4-PVA-based electrolytes, especially in terms of the effects of fillers on the dynamic equilibrium of free protons and protonated water in the electrolytes.

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

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Difilipo, Frank

    1990-01-01

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

  17. Synthesis, structure and NMR characterization of a new monomeric aluminophosphate [ dl-Co(en) 3] 2[Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2](H 3PO 4) 4 containing four different types of monophosphates

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Li, Jiyang; Xu, Jun; Duan, Fangzheng; Deng, Feng; Xu, Ruren

    2009-03-01

    A new zero-dimensional (0D) aluminophosphate monomer [ dl-Co(en) 3] 2[Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2](H 3PO 4) 4 (designated AlPO-CJ38) with Al/P ratio of 1/6 has been solvothermally prepared by using racemic cobalt complex dl-Co(en) 3Cl 3 as the template. The Al atom is octahedrally linked to six P atoms via bridging oxygen atoms, forming a unique [Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2] 6- monomer. Notably, there exists intramolecular symmetrical O⋯H⋯O bonds, which results in pseudo-4-rings stabilized by the strong H-bonding interactions. The structure is also featured by the existence of four different types of monophosphates that have been confirmed by 31P NMR and 1H NMR spectra. The crystal data are as follows: AlPO-CJ38, [ dl-Co(en) 3] 2[Al(HPO 4) 2(H 1.5PO 4) 2(H 2PO 4) 2](H 3PO 4) 4, M = 1476.33, monoclinic, C2/ c (No. 15), a = 36.028(7) Å, b = 8.9877(18) Å, c = 16.006(3) Å, β = 100.68(3)°, U = 5093.2(18) Å 3,Z = 4, R1 = 0.0509 ( I > 2 σ( I)) and wR2 = 0.1074 (all data). CCDC number 689491.

  18. COMPARATIVE SO2 REACTIVITY OF CAO DERIVED FROM CACO3 AND CA(OH)2

    EPA Science Inventory

    Experimental data on sulfation rates of CaO particles derived from CaCO3 are compared to those derived from Ca(OH)2 using a product layer diffusion control model differing only in the shape of the CaO grain. Both the model and the experimental data indicate slightly higher reacti...

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

    PubMed Central

    Mun, Ju-Hyun; Hwang, Hey-Zoo

    2014-01-01

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

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

    PubMed

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

    2005-11-22

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

  1. [Dentinopulpar organ: biological basis of clinical response to Ca(OH)2 application].

    PubMed

    Gani, O; Crosa, M E

    1989-01-01

    We have studied the changes presented by mediate and immediate roentgenographic images of indirect pulp capping and pulpotomies. In the cases of indirect pulp capping it was observed an increase of radiolucidity in the places occupied by Ca(OH)2, and sclerotic dentin was present. In pulpotomies, it was found the dentin bridge, which thickness increases with time. The radiolucidity of pulp chamber occupied by Ca(OH)2 was greater in the long time treatment. The radiopacity of non-vital dentin of walls and floor chamber was increased too. It has suggested that Ca++ ion would have migrated from its place and probably would take part in the synthesis of sclerotic dentin, independently of the vitality of the tissue.

  2. 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.

  3. [Dentinopulpar organ: biological basis of clinical response to Ca(OH)2 application].

    PubMed

    Gani, O; Crosa, M E

    1989-01-01

    We have studied the changes presented by mediate and immediate roentgenographic images of indirect pulp capping and pulpotomies. In the cases of indirect pulp capping it was observed an increase of radiolucidity in the places occupied by Ca(OH)2, and sclerotic dentin was present. In pulpotomies, it was found the dentin bridge, which thickness increases with time. The radiolucidity of pulp chamber occupied by Ca(OH)2 was greater in the long time treatment. The radiopacity of non-vital dentin of walls and floor chamber was increased too. It has suggested that Ca++ ion would have migrated from its place and probably would take part in the synthesis of sclerotic dentin, independently of the vitality of the tissue. PMID:2640037

  4. Intrinsic Proton NMR Studies of Mg(OH)2 and Ca(OH)2

    NASA Astrophysics Data System (ADS)

    Itoh, Yutaka; Isobe, Masahiko

    2016-09-01

    We studied the short proton free induction decay signals and the broad 1H NMR spectra of Mg(OH)2 and Ca(OH)2 powders at 77-355 K and 42 MHz using pulsed NMR techniques. Using a Gaussian-type back extrapolation procedure for the obscured data of the proton free induction decay signals, we obtained more precise values of the second moments of the Fourier-transformed broad NMR spectra than those in a previous report [Y. Itoh and M. Isobe, J. Phys. Soc. Jpn. 84, 113601 (2015)] and compared with the theoretical second moments. The decrease in the second moment could not account for the large decrease in the magnitude of the intrinsic proton spin-lattice relaxation rate 1/T1 from Mg(OH)2 to Ca(OH)2. The analysis of 1/T1 ∝ exp(-Eg/kBT) with Eg ˜ 0.01 eV points to a local hopping mechanism, and that of 1/T1 ∝ Tn with n ˜ 0.5 points to an anharmonic rattling mechanism.

  5. Biosorption and retention of orthophosphate onto Ca(OH)2-pretreated biomass of Phragmites sp.

    PubMed

    Markou, Giorgos; Mitrogiannis, Dimitris; Muylaert, Koenraad; Çelekli, Abuzer; Bozkurt, Hüseyin

    2016-07-01

    The biosorption of phosphorus in the form of orthophosphate (Po) from wastewater using biomass as the sorbent is of potential importance because the Po-loaded biomass could be applied in the agricultural sector as fertilizer and soil conditioner. However, biomass generally displays a very low affinity for Po sorption and therefore biomass surface modification is required. In the present study, the biomass (as model grinded leaves of Phragmites sp. were used) was pretreated with Ca(OH)2 to enhance Po biosorption capacity (qe). The results indicate that the alkaline pretreatment resulted in a modification of surface functional groups. It was concluded that the main sorption mechanisms were ligand exchange and electrostatic attraction. A series of experiments were conducted to investigate the performance of the pretreated biomass for Po uptake under various conditions. Isotherm and thermodynamic studies were also applied and analyzed. The biosorption process was best described by the pseudo-second order kinetic model and Langmuir isotherm, which gave a qmax of 12.27mgP/g at 25°C and pH7. The Ca(OH)2 treated Phragmites biomass applied in this study for Po recovery may present some potential advantages in terms of costs and environmental impact. PMID:27372118

  6. Intrinsic Proton NMR Studies of Mg(OH)2 and Ca(OH)2

    NASA Astrophysics Data System (ADS)

    Itoh, Yutaka; Isobe, Masahiko

    2016-09-01

    We studied the short proton free induction decay signals and the broad 1H NMR spectra of Mg(OH)2 and Ca(OH)2 powders at 77-355 K and 42 MHz using pulsed NMR techniques. Using a Gaussian-type back extrapolation procedure for the obscured data of the proton free induction decay signals, we obtained more precise values of the second moments of the Fourier-transformed broad NMR spectra than those in a previous report [Y. Itoh and M. Isobe, http://doi.org/10.7566/JPSJ.84.113601, J. Phys. Soc. Jpn. 84, 113601 (2015)] and compared with the theoretical second moments. The decrease in the second moment could not account for the large decrease in the magnitude of the intrinsic proton spin-lattice relaxation rate 1/T1 from Mg(OH)2 to Ca(OH)2. The analysis of 1/T1 ∝ exp(-Eg/kBT) with Eg ˜ 0.01 eV points to a local hopping mechanism, and that of 1/T1 ∝ Tn with n ˜ 0.5 points to an anharmonic rattling mechanism.

  7. 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.

  8. 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...

  9. Lake restoration by hypolimnetic Ca(OH)2 treatment: impact on phosphorus sedimentation and release from sediment.

    PubMed

    Dittrich, Maria; Gabriel, Oliver; Rutzen, Christian; Koschel, Rainer

    2011-03-15

    A whole-lake hypolimnetic Ca(OH)(2) addition, that induced calcium carbonate precipitation, combined with deep water aeration has been applied to eutrophic Lake Luzin, Germany during 1996-1998. In this study we investigated the dynamic of phosphorus and its binding forms in seston and sediment before and during the treatment. The sedimentation rates of phosphorus increased within three years of induced calcite precipitation. The phosphorus binding forms shifted to the calcite-bound phosphorus in the settling matter. The increase of calcite-bound P in the settling material did not coincide with the maximum induced CaCO(3)-precipitation caused by the hypolimnetic addition of Ca(OH)(2). An impact of chemicals additions and pH on phosphorus binding forms in seston and surface sediments has been studied in laboratory experiments with sediment core incubations and slurry experiments. Laboratory studies showed that the lowest phosphorus flux from sediment was related to the experiment with pH=7 in overlaying water adjusted with Ca(OH)(2). The adjusting of pH with Ca(OH)(2) leads to a lower P flux of 2.3 mg Pm(-2)d(-1), while the highest P-flux is attributed to the experiment with the pH which was adjusted with NaOH. Phosphorus fraction which reflects phosphorus binding on carbonates in surface sediments increased within one year of treatment, enhancing the phosphorus retention capacity of sediments. PMID:21292312

  10. Commercial Ca(OH)2 nanoparticles for the consolidation of immovable works of art

    NASA Astrophysics Data System (ADS)

    Baglioni, P.; Chelazzi, D.; Giorgi, R.; Carretti, E.; Toccafondi, N.; Jaidar, Y.

    2014-03-01

    Calcium hydroxide nanoparticles are effective components for the consolidation treatment of immovable works of art, such as carbonate stone and wall paintings that exhibit both surface and structural degradation. Several formulations have been recently developed, with different characteristics (dispersing solvent, particle size distribution and particle structure), which are expected to result in different long-term consolidating properties. In this contribution, the carbonation of a commercial Ca(OH)2 nanoparticle formulation (Nanorestore®) was characterized through Fourier transform infrared (FTIR) analysis. Nanoparticle films were laid on KBr pellets and stored at room temperature under controlled relative humidity and CO2 pressure. FTIR analysis was used to quantitatively detect the formation of calcium carbonate. Fitting of the experimental data allowed the description of the mechanism of carbonate nucleation and growth. The compatibility of the Nanorestore® formulation for wall painting consolidation was assessed through optical and electron microscopy, colorimetry and water absorption capillarity measurements. The formulation's effectiveness in consolidating powdering painted layers was assessed through application on site and on detached samples of Mesoamerican wall paintings belonging to the pre-Columbian archaeological sites of Ixcaquixtla and Calakmul (Mexico).

  11. 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.

  12. 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.

  13. 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.

  14. Enhancement of anaerobic treatability of olive oil mill effluents by addition of Ca(OH)2 and bentonite without intermediate solid/liquid separation.

    PubMed

    Beccari, M; Majone, M; Papini, M P; Torrisi, L

    2001-01-01

    Previous work on the anaerobic treatment of olive oil mill effluents (OME) have shown: (a) lipids, even if more easily degraded than phenols, were potentially capable of inhibiting methanogenesis more strongly; (b) a pretreatment based on addition of Ca(OH)2 and bentonite removed lipids almost quantitatively; (c) preliminary biotreatability tests performed on the pretreated OME showed high bioconversion into methane at very low dilutions ratios, especially when the mixture (OME, Ca(OH)2 and bentonite) was fed to the biological treatment without providing an intermediate phase separation. This paper was directed towards two main aims: (a) to optimize pretreatment: the best results in terms of methane production were obtained by addition of Ca(OH)2 up to pH 6.5 and of 10 g L-1 of bentonite; (b) to evaluate the enhancement of anaerobic treatability of OME pretreated under optimized conditions in a lab-scale continuous methanogenic reactor fed with the substrate without intermediate solid/liquid separation: very satisfactory performances were obtained (at an organic load of 8.2 kg COD m-3 d-1 and at a dilution ratio of 1:1.5 total COD removal was 91%, biogas production was 0.80 g CH4 (as COD)/g tot. COD, lipids removal was 98%, phenols removal was 63%). The results confirm the double role played by bentonite (adsorption of the inhibiting substances and release of the adsorbed biodegradable matter in the methanogenic reactor).

  15. Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

    PubMed Central

    Yu, Lei; Han, Mengting; Luan, Jie; Xu, Lin; Ding, Yuanhua; Xu, Qing

    2016-01-01

    Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5–10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its 1H NMR spectrum. PMID:27443482

  16. Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

    NASA Astrophysics Data System (ADS)

    Yu, Lei; Han, Mengting; Luan, Jie; Xu, Lin; Ding, Yuanhua; Xu, Qing

    2016-07-01

    Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5-10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its 1H NMR spectrum.

  17. Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

    NASA Astrophysics Data System (ADS)

    Yu, Lei; Han, Mengting; Luan, Jie; Xu, Lin; Ding, Yuanhua; Xu, Qing

    2016-07-01

    Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5–10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its 1H NMR spectrum.

  18. Effect of Ca(OH)2, NaCl, and Na2SO4 on the corrosion and electrochemical behavior of rebar

    NASA Astrophysics Data System (ADS)

    Jin, Zuquan; Zhao, Xia; Zhao, Tiejun; Hou, Baorong; Liu, Ying

    2016-06-01

    The corrosion of rebar in reinforced concrete in marine environments causes significant damage to structures built in ocean environments. Studies on the process and mechanism of corrosion of rebar in the presence of multiple ions may help to control damage and predict the service life of reinforced concrete structures in such environments. The effect of interactions between sulfate and chloride ions and calcium hydroxide on the electrochemical behavior of rebar are also important for evaluation of structure durability. In this work, electrochemical impedance spectroscopy (EIS) plots of rebar in Ca(OH)2 solution and cement grout, including NaCl and Na2SO4 as aggressive salts, were measured for diff erent immersion times. The results show that corrosion of rebar was controlled by the rate of charge transfer as the rebar was exposed to chloride solution. In the presence of high concentrations of sulfate ions in the electrolyte, generation and dissolution of the passive film proceeded simultaneously and corrosion was mainly controlled by the diff usion rate. When Na2SO4 and NaCl were added to Ca(OH)2 solution, the instantaneous corrosion rate decreased by a factor of 10 to 20 as a result of the higher pH of the corroding solution.

  19. Characterization and ciprofloxacin adsorption properties of activated carbons prepared from biomass wastes by H3PO4 activation.

    PubMed

    Sun, Yuanyuan; Li, Hong; Li, Guangci; Gao, Baoyu; Yue, Qinyan; Li, Xuebing

    2016-10-01

    As biomass wastes, Arundo donax Linn and pomelo peel were used as precursors for activated carbons (ALAC and PPAC) preparation by phosphoric acid activation. The pore structure and surface acidic functional groups of both carbons were characterized by nitrogen adsorption/desorption experiment, NH3-temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR). A batch of experiments was carried out to investigate the adsorption performances of ciprofloxacin under different conditions. Results showed that PPAC exhibited larger surface area (1252m(2)/g) and larger portion of mesoporous, while ALAC was typical of microporous materials. Results from NH3-TPD suggested that ALAC was characteristic of more acidic functional group than PPAC. The maximum monolayer adsorption capability was 244mg/g for ALAC and 400mg/L for PPAC. Kinetics studies showed intra-particle diffusion was not the unique rate-controlling step. Boundary layer resistance existed between adsorbent and adsorbate.

  20. Numerical Modeling of In-situ Reaction Barrier by Injection of Ca(OH)2 Solution for CO2 Geological Storage

    NASA Astrophysics Data System (ADS)

    Xu, T.; Ito, T.

    2008-12-01

    Containment of CO2 in the storage reservoir is a very important issue. We present here an in-situ reaction barrier method to reduce the medium permeability along potential leakage paths of a deep CO2 storage reservoir in a saline formation. An aqueous solution will be injected into the fractures and rocks through injection wells. The solution will have a low viscosity and will not impact formation permeability as long as the solution is left as it is, but when the solution encounters dissolved CO2, precipitation will occur due to chemical reaction. As a result, the permeability will be reduced by filling the pores and fractures in the rocks with the precipitates. This concept has been successfully demonstrated previously through a laboratory experiment using Ca(OH)2 solution. The reduction of permeability in the laboratory experiment has been reproduced by reactive transport modeling using TOUGHREACT. The concept of the in-situ reaction barrier has been applied to a 2-D caprock-aquifer system under field physical and chemical conditions using the modeling tool. Calcite precipitation, permeability reduction, and CO2 leakage mitigation was achieved in the numerical experiment. This concept may be also applicable to prevent the leakage through abandoned wells, to mitigate well cement degradation, and to enhance CO2 mineral trapping.

  1. 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.

  2. Modelling of the vapour-liquid equilibrium of water and the in situ concentration of H3PO4 in a high temperature proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Kazdal, Timur J.; Lang, Sebastian; Kühl, Frank; Hampe, Manfred J.

    2014-03-01

    The fuel cell technology is a key element for the hydrogen energy economy and therefore crucial for sustainable development. High temperature proton exchange membrane (HT-PEM) fuel cells (FC) can be operated with reformate gas and thus represent an important bridging technology for the energy transition to a renewable energy based system. HT-PEM FCs based on phosphoric acid (PA) are still subject to intense research, investigating the electrolyte behaviour. By enhancing state of the art 2D FEM simulations of FCs with the vapour liquid equilibrium of water-phosphoric acid and evaporation kinetics, a model was created in which the local concentration of PA can be calculated. Knowledge of the concentration field yields the basis for calculating the locally varying ionic conductivity and other physical properties. By describing the volume expansion behaviour of PA it was possible to predict the catalyst particle deactivation due to the swelling of PA. The in situ concentration predicted by the simulation ranges from 96 to 111 wt%. The model was validated using measured data of a single cell design for different temperatures and pressures. By varying the PA content flooding of the simulated fuel cell could be observed and was linked to humidification effects.

  3. 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

  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.

  5. Grain-boundary migration in KCl bicrystals

    NASA Technical Reports Server (NTRS)

    Gibbon, C. F.

    1968-01-01

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

  6. Composition gradients in electrolyzed LiCl-KCl eutectic melts

    NASA Astrophysics Data System (ADS)

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

    1983-12-01

    Analysis of transport in a mixed electrolyte has previously predicted significant composition gradients in the LiCl-KCl electrolyte of high temperature LiS/ batteries. Composition gradients in quenched electrolyzed LiCl-KCl eutectic contained in yttria felt are measured with high distance resolution by scanning electron microscopy with energy dispersive X-ray spectroscopy. The reported results include composition profiles of LiCl-KCl coontained in porous Y2O3 and electrolyzed in three cells, two with solid Li-Al electrodes and one with a porous Li-Al anode.

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

    SciTech Connect

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

    1994-05-01

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

  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. 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....

  10. Study of an F center in molten KCl

    SciTech Connect

    Parrinello, M.; Rahman, A.

    1983-05-01

    It is shown that a discretized version of Feynman's path integral provides a convenient tool for the numerical investigation of the properties of an electron solvated in molten KCl. The binding energy and the pair correlation functions are calculated. The local structure around the solute electron appears to be different from that of an F center in the solid.

  11. KCl:Dy phosphor for thermoluminescence dosimetry of ionizing radiation.

    PubMed

    Bhujbal, P M; Dhoble, S J

    2013-01-01

    The thermoluminescence (TL) characterizations of γ-irradiated KCl:Dy phosphor for radiation dosimetry are reported. All phosphors were synthesized via a wet chemical route. Minimum fading of TL intensity is recorded in the prepared material. TL in samples containing different concentrations of Dy impurity was studied at different γ-irradiation doses. Peak TL intensities varied sublinearly with γ-ray dose in all samples, but were linear between 0.08 to 0.75 kGy for the KCl:Dy (0.1 mol%) sample. This material may be useful for dosimetry within this range of γ-ray dose. TL peak height was found to be dependant on the concentration (0.05-0.5 mol%) of added Dy in the host.

  12. [The content of nutrient elements of plant in KCl fertilizer].

    PubMed

    Xu, Fang; Rui, Yu-Kui; Lin, Qiang; Zhang, Fu-Suo

    2009-03-01

    Potassium is one of the three most important plant nutrient elements, so many researchers pay attention on its fertilizer efficiency. But fertilizers were all industrial products containing many other nutrient elements in most experiments of fertilizer efficiency. All the other nutrient elements, including necessitous elements and beneficial elements in potassium fertilizer (KCl) were analyzed by method of ICP-MS. The results showed that KCl fertilizer contained many necessitous elements (Mg, Ca, Mn, Fe, Ni, Cu, Zn and Mo), the concentrations of them are 50.51, 1 309.48, 5.44, 500.83 microg x g(-1) and 65.54, 238.85, 212.44, 10.40 ng x g(-1) respectively; beneficial elements (Na, Al, Si, Co and Se) are 25 095.89, 3.83, 3.40 microg x g(-1) and 13.12, 23.25 ng x g(-1) respectively. All the above elements could influence the results of potassium fertilizer efficiency experiments, so pure fertilizer should be used in the future potassium fertilizer efficiency experiments.

  13. K-Cl cotransporters, cell volume homeostasis, and neurological disease.

    PubMed

    Kahle, Kristopher T; Khanna, Arjun R; Alper, Seth L; Adragna, Norma C; Lauf, Peter K; Sun, Dandan; Delpire, Eric

    2015-08-01

    K(+)-Cl(-) cotransporters (KCCs) were originally characterized as regulators of red blood cell (RBC) volume. Since then, four distinct KCCs have been cloned, and their importance for volume regulation has been demonstrated in other cell types. Genetic models of certain KCCs, such as KCC3, and their inhibitory WNK-STE20/SPS1-related proline/alanine-rich kinase (SPAK) serine-threonine kinases, have demonstrated the evolutionary necessity of these molecules for nervous system cell volume regulation, structure, and function, and their involvement in neurological disease. The recent characterization of a swelling-activated dephosphorylation mechanism that potently stimulates the KCCs has pinpointed a potentially druggable switch of KCC activity. An improved understanding of WNK/SPAK-mediated KCC cell volume regulation in the nervous system might reveal novel avenues for the treatment of multiple neurological diseases. PMID:26142773

  14. 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.

  15. 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.

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

    PubMed

    Leng, Yongsheng

    2012-03-27

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

  17. 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.

  18. 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.

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

    SciTech Connect

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

    1981-01-01

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

  20. Phase equilibria of NdC1 3NaClKCl

    NASA Astrophysics Data System (ADS)

    Hosoya, Yuji; Terai, Takayuki; Tanaka, Satoru; Takahashi, Yoichi

    1997-08-01

    Molten chloride is considered to be applied to a fast-breeder-reactor fuel and a solvent in the pyrochemical reprocessing of spent nuclear fuel. In this work, phase diagrams for molten chloride systems were constructed, using NdCl 3 as an imitative substance in place of UCl 3 or PuCl 3. A compound of 3NdC1 3 · NaCl, which melts incongruently at 540°C to NdCl 3 and liquid and a eutectic at 437°C were found in the NdC1 3NaCl system. In the NdCl 3KCl system, many invariant reactions were observed: the decomposition of NdCl 3 · 2KCl and 2NdCl 3 · KCl at 444 and 474°C, respectively; a eutectic at 489°C; a peritectic at 506°C and a monotectic at 624°C. It is thought that there should be a peritectic compound of 6NdCl 3 · KCl above 474°C. A compound of 2NdC1 3 · NaCl · KCl was considered to exist in the ternary system of NdCl 3NaClKCl, to which attention should be paid in determining the composition of the fuel of the molten-salt fast breeder reactor.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    Changes in the optical absorption coefficient as 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.

  2. 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.

  3. 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

  4. Integrated Data Collection Analysis (IDCA) Program - KClO4/Aluminum Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorensen, Daniel N.; Remmers, Daniel L.; Whinnery, LeRoy L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2012-01-17

    The Integrated Data Collection Analysis (IDCA) program is conducting a Proficiency Test for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4 and aluminum—KClO4/Al mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solids. The mixture was found to be: 1) much less sensitive to impact than RDX, (LLNL being the exception) and PETN, 2) more sensitive to friction than RDX and PETN, and 3) extremely sensitive to spark. The thermal analysis showed little or no exothermic character. One prominent endothermic feature was observed in the temperature range studied and identified as a phase transition of KClO4.

  5. Optical properties of bismuth-doped KCl and SrF2 crystals

    NASA Astrophysics Data System (ADS)

    Firstov, S. V.; Zhao, M.; Su, L.; Yang, Q.; Iskhakova, L. D.; Firstova, E. G.; Alyshev, S. V.; Riumkin, K. E.; Dianov, E. M.

    2016-09-01

    Structural and spectroscopic properties of the pristine and γ-irradiated Bi-doped KCl and SrF2 crystals grown by the Bridgman technique were studied. New emission bands in the visible and near IR regions from the irradiated crystals were observed. An origin of optical centers responsible for near IR luminescence is discussed.

  6. 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.

  7. Microphysics of KCl and ZnS Clouds on GJ 1214 b

    NASA Astrophysics Data System (ADS)

    Gao, Peter; Benneke, Björn

    2016-10-01

    Clouds are ubiquitous in the atmospheres of exoplanets. However, as most of these planets have temperatures between 600 and 2000 K, their clouds are likely composed of exotic condensates such as salts, sulfides, silicates, and metals. Treatment of these clouds in current exoplanet atmosphere models do not consider the microphysical processes that govern their formation, evolution, and distribution, such as nucleation and condensation/evaporation, thus creating a gulf between the cloud properties retrieved from observations and the cloud composition predictions from condensation equilibrium models. In this work, we apply a 1D microphysical cloud model to GJ 1214 b and investigate the properties of potassium chloride (KCl) and zinc sulfide (ZnS) clouds as a function of atmospheric metallicity, the intensity of vertical mixing, and the mode of nucleation. Our cloud model has been widely applied to planets in our own Solar System, and as such our work bridges a gap between planetary science and exoplanets. Using model background atmospheres calculated by the SCARLET code, we find that (1) the cloud distribution is not significantly affected by metallicity unless [Fe/H] > 2, (2) higher intensities of vertical mixing leads to more extended cloud decks, more cloud particles at all altitudes, and smaller mean particle radii, (3) the high surface energy of solid ZnS prevents the homogeneous nucleation of pure ZnS cloud particles, such that KCl clouds dominate; solid ZnS can only manifest by nucleating onto pre-existing surfaces (heterogeneous nucleation), such as KCl cloud particles, resulting in mixed clouds, and (4) formation of KCl clouds results in a KCl vapor abundance above the cloud deck ~5 orders of magnitude less than that calculated from equilibrium chemistry. We also examine the transmission spectra that would result from these different cases. Extension of this model to other planets and condensates will shed light on the observed continuum in the "cloudiness

  8. Cooperative protein-DNA interactions: effects of KCl on lambda cI binding to OR.

    PubMed

    Koblan, K S; Ackers, G K

    1991-08-01

    The effects of monovalent salt activity on the site-specific and cooperative interactions of cI repressor with its three operator sites OR were studied by using quantitative DNase I footprint titration methods. Individual-site binding isotherms were obtained for binding repressor dimers to each site of wild-type OR and to mutant operator templates in which binding to one or two sites has been eliminated. The standard Gibbs energies for intrinsic binding, delta G1, delta G2, and delta G3, and cooperative interactions, delta G12 and delta G23, were determined at each condition (range 50-200 mM KCl). It is found that the dimer affinity for each of the three sites increases as [KCl] decreases, a striking result given that the monomer-dimer equilibrium shifts toward monomer formation under identical solution conditions [Koblan, K. S., & Ackers, G. K. (1991) Biochemistry (preceding paper in this issue)]. The magnitudes of ion-linked effects are found to differ at the three operator sites, while the intrinsic interaction binding free energies for sites OR1 and OR3 change in parallel over the entire range of [KCl]. The KCl dependencies at OR1 and OR3 represent the average release of 3.7 +/- 0.6 and 3.8 +/- 0.6 apparent ions, respectively. By contrast, the KCl dependency of OR2 binding corresponds to the displacement of 5.2 +/- 0.7 apparent ions. The ability of cI repressor to discriminate between the three operator sites thus appears linked to ion binding/release reactions.

  9. 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

  10. 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

  11. Kinetic comparison of ouabain-resistant K:Cl fluxes (K:Cl [Co]-transport) stimulated in sheep erythrocytes by membrane thiol oxidation and alkylation.

    PubMed

    Lauf, P K

    1988-01-01

    The stimulatory effects of two thiol (SH) group oxidants, methylmethane thiosulfonate (MMTS) and diazene dicarboxylic acid bis [N,N-dimethylamide] (diamide), on the kinetics of ouabain-resistant (OR) K:Cl [co]-transport in low K (LK) sheep red blood cells were compared with the effects of alkylating agents, notably N-ethylmaleimide (NEM). At low concentrations, both MMTS and diamide stimulated K:Cl [co]-transport, and with a latency period, as measured by OR zero-trans K efflux and OR uptake of external Rb, Rbo, as K congener in Cl and NO3 media. At high concentrations the effect of diamide saturated, and that of MMTS disappeared. The stimulatory effect of MMTS was partially reversed by the reducing agent dithiothreitol (DTT) known to fully restore the diamide-activated K flux (Lauf, J. Memb. Biol. 101:179-188, 1988). In diamide preequilibrated LK sheep red cells, the Km of K:Cl [co]-transport for external Cl, Clo, was 84.3 mM, and 18.7 mM for Rbo, with nearly identical Vmax values around 4 mmol Rb/L cells x h for K (Rb) fluxes in Cl and after correction for the small Cl-independent component. Zero net K (Rb) flux existed at Kc (cell K)/Rbo concentration ratios, [K]c/[Rb]c, of 0.8 i.e. when the electrochemical driving forces across the membrane were about equal. The measured K efflux/Rb influx ratios were almost twice those predicted from [K]c/[Rb]o and the Cl equilibrium potential suggesting that the diamide-stimulated K (Rb) flux may occur through non-diffusional, carrier-mediated transport.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3185522

  12. Effect of KCl substitution on bacterial viability of Escherichia coli (ATCC 25922) and selected probiotics.

    PubMed

    Gandhi, Akanksha; Cui, Yuxiang; Zhou, Mingyang; Shah, Nagendra P

    2014-10-01

    Excessive intake of NaCl has been associated with the increased risk of several diseases, particularly hypertension. Strategies to reduce sodium intake include substitution of NaCl with other salts, such as KCl. In this study, the effects of NaCl reduction and its substitution with KCl on cell membranes of a cheese starter bacterium (Lactococcus lactis ssp. lactis), probiotic bacteria (Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus casei), and a pathogenic bacterium (Escherichia coli) were investigated using Fourier-transform infrared (FTIR) spectroscopy. A critical NaCl concentration that inhibited the viability of E. coli without affecting the viability of probiotic bacteria significantly was determined. To find the critical NaCl concentration, de Man, Rogosa, and Sharpe (MRS) broth was supplemented with a range of NaCl concentrations [0 (control), 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0%], and the effect on cell viability and FTIR spectra was monitored for all bacteria. A NaCl concentration of 2.5% was found to be the critical level of NaCl to inhibit E. coli without significantly affecting the viability of most of the probiotic bacteria and the cheese starter bacterium. The FTIR spectral analysis also highlighted the changes that occurred mainly in the amide regions upon increasing the NaCl concentration from 2.5 to 3.0% in most of the bacteria. Escherichia coli and B. longum were more sensitive to substitution of NaCl with KCl, compared with Lb. acidophilus, Lb. casei, and Lc. lactis ssp. lactis. To evaluate the effect of substitution of NaCl with KCl, substitution was carried out at the critical total salt concentration (2.5%, wt/vol) at varying concentrations (0, 25, 50, 75, and 100% KCl). The findings suggest that 50% substitution of NaCl with KCl, at 2.5% total salt, could inhibit E. coli without affecting the probiotic bacteria.

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

    NASA Astrophysics Data System (ADS)

    Thaila, T.; Kumararaman, S.

    2011-11-01

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

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

    PubMed

    Thaila, T; Kumararaman, S

    2011-11-01

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

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

    SciTech Connect

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

    1985-01-01

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

  16. 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.

  17. Slow highly charged ion induced nanopit formation on the KCl(001) surface

    NASA Astrophysics Data System (ADS)

    Wilhelm, R. A.; Heller, R.; Facsko, S.

    2016-08-01

    We report on nanostructuring of the KCl(001) surface induced by the individual impact of slow highly charged ions. Samples were irradiated with Xe ions with charge states of Q = 15 to 40 at kinetic energies from 1.7 to 160 keV. The formation of nanopits at the virgin surface is observed and attributed to a defect-mediated desorption process involving the removal of up to 2000 surface atoms per incident ion. The depth of the produced pits is shallow, but not limited to the first monolayer. From the variation of the ion parameters (charge state and kinetic energy) we derive a phase diagram for the structuring of the KCl(001) surface with highly charged ions.

  18. Cyclic Corrosion and Chlorination of an FeCrAl Alloy in the Presence of KCl

    DOE PAGESBeta

    Israelsson, Niklas; Unocic, Kinga A.; Hellström, K.; Svensson, J-E; Johansson, L-G

    2015-05-30

    The KCl-induced corrosion of the FeCrAl alloy Kanthal® APMT in an O2 + N2 + H2O environment was studied at 600 °C. The samples were pre-oxidized prior to exposure in order to investigate the protective nature of alumina scales in the present environment. The microstructure and composition of the corroded surface was investigated in detail. Corrosion started at flaws in the pre-formed α-alumina scales, i.e. α-alumina was protective in itself. Consequently, KCl-induced corrosion started locally and, subsequently, spread laterally. An electrochemical mechanism is proposed here by which a transition metal chloride forms in the alloy and K2CrO4 forms at themore » scale/gas interface. Scale de-cohesion is attributed to the formation of a sub-scale transition metal chloride.« less

  19. Integrated Data Collection Analysis (IDCA) Program - KClO3/Dodecane Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorenson, Daniel N.; Remmers, Daniel L.; Shelley, Timothy J.; Whinnery, LeRoy L.; Hsu, Peter C.; Reynolds, John G.

    2011-05-23

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO3 and dodecane—KClO3/dodecane mixture. This material was selected because of the challenge of performing SSST testing of a mixture of solid and liquid materials. The mixture was found to: 1) be more sensitive to impact than RDX, and PETN, 2) less sensitive to friction than PETN, and 3) less sensitive to spark than RDX. The thermal analysis showed little or no exothermic features suggesting that the dodecane volatilized at low temperatures. A prominent endothermic feature was observed assigned to melting of KClO3. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed to develop safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. The results are compared among the laboratories and then compared to historical data from various sources. The testing performers involved for the KClO3/dodecane mixture are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), and Indian Head Division, Naval Surface Warfare Center, (NSWC IHD). These tests are conducted as a proficiency study in order to establish some consistency in test protocols, procedures, and experiments and to understand

  20. 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. PMID:27345778

  1. 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. PMID:27345813

  2. 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. PMID:27345800

  3. 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. PMID:27345807

  4. 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. PMID:27345806

  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. PMID:27345799

  6. 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.

  7. 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.

  8. Characterization of Fe/KClO4 heat powders and pellets.

    SciTech Connect

    Reinhardt, Frederick William; Guidotti, Ronald Armand; Odinek, Judy Gail

    2005-04-01

    Pellets of Fe/KClO{sub 4} mixtures are used as a heat source for thermally activated ('thermal') batteries. They provide the energy necessary for melting the electrolyte and bringing the battery stack to operating temperature. The effects of morphology of the Fe and the heat-pellet density and composition on both the physical properties (flowability, pelletization, and pellet strength) and the pyrotechnic performance (burn rate and ignition sensitivity) were examined using several commercial sources of Fe.

  9. Mouse K-Cl cotransporter KCC1: cloning, mapping, pathological expression, and functional regulation.

    PubMed

    Su, W; Shmukler, B E; Chernova, M N; Stuart-Tilley, A K; de Franceschi, L; Brugnara, C; Alper, S L

    1999-11-01

    Although K-Cl cotransporter (KCC1) mRNA is expressed in many tissues, K-Cl cotransport activity has been measured in few cell types, and detection of endogenous KCC1 polypeptide has not yet been reported. We have cloned the mouse erythroid KCC1 (mKCC1) cDNA and its flanking genomic regions and mapped the mKCC1 gene to chromosome 8. Three anti-peptide antibodies raised against recombinant mKCC1 function as immunoblot and immunoprecipitation reagents. The tissue distributions of mKCC1 mRNA and protein are widespread, and mKCC1 RNA is constitutively expressed during erythroid differentiation of ES cells. KCC1 polypeptide or related antigen is present in erythrocytes of multiple species in which K-Cl cotransport activity has been documented. Erythroid KCC1 polypeptide abundance is elevated in proportion to reticulocyte counts in density-fractionated cells, in bleeding-induced reticulocytosis, in mouse models of sickle cell disease and thalassemia, and in the corresponding human disorders. mKCC1-mediated uptake of (86)Rb into Xenopus oocytes requires extracellular Cl(-), is blocked by the diuretic R(+)-[2-n-butyl-6,7-dichloro-2-cyclopentyl-2, 3-dihydro-1-oxo-1H-indenyl-5-yl-)oxy]acetic acid, and exhibits an erythroid pattern of acute regulation, with activation by hypotonic swelling, N-ethylmaleimide, and staurosporine and inhibition by calyculin and okadaic acid. These reagents and findings will expedite studies of KCC1 structure-function relationships and of the pathobiology of KCC1-mediated K-Cl cotransport.

  10. Relative osmotic effects of raffinose, KCl, and NaCl across basolateral cell membrane.

    PubMed

    Welling, L W; Welling, D J; Ochs, T

    1990-10-01

    Lumen-collapsed segments of rabbit S2 proximal tubule were bathed in isotonic medium and then exposed acutely to a medium made hypertonic by the addition of raffinose, NaCl, KCl, Na gluconate, K gluconate, or choline Cl. The result was a rapid efflux of water and a shrinking of the tubule, which could be measured by video techniques within the first 0.1 s. After reequilibration in isotonic medium, each tubule was then exposed to a second hypertonic medium to provide a direct comparison between two different solutes, either NaCl vs. KCl or raffinose vs. any one of the other solutes. Because raffinose is impermeant across the basolateral cell membrane, the ratio of its effect to that of another solute is a measure of the reflection coefficient (sigma) of that other solute. The following results were obtained: sigma KCl = 0.70 +/- 0.02, sigma K gluconate = 0.97 +/- 0.07, sigma Na gluconate = 0.84 +/- 0.06, and sigma choline Cl = 0.75 +/- 0.06. We previously have reported sigma NaCl = 0.56 +/- 0.07. If sigma of each salt is considered to be the arithmetic average of its component parts, and if gluconate and choline are considered to be impermeant, we also obtain sigma Na+ = 0.68, sigma K+ = 0.94, and sigma Cl- = 0.50. PMID:2221098

  11. On the electrochemical formation of Pu-Al alloys in molten LiCl-KCl

    NASA Astrophysics Data System (ADS)

    Mendes, E.; Malmbeck, R.; Nourry, C.; Souček, P.; Glatz, J.-P.

    2012-01-01

    Properties of Pu-Al alloys were investigated in connection with development of pyrochemical methods for reprocessing of spent nuclear fuel. Electroseparation techniques in molten LiCl-KCl are being developed in ITU to group-selectively recover actinides from the mixture with fission products. In the process, actinides are electrochemically reduced on solid aluminium cathodes, forming solid actinide-aluminium alloys. This article is focused on electro-chemical characterisation of Pu-Al alloys in molten LiCl-KCl, on electrodeposition of Pu on solid Al electrodes and on determination of chemical composition and structure of the formed alloys. Cyclic voltammetry and chronopotentiometry were used to study Pu-Al alloys in the temperature range 400-550 °C. Pu is reduced to metal in one reduction step Pu 3+/Pu 0 on an inert W electrode. On a reactive Al electrode, the reduction of Pu 3+ to Pu 0 occurs at a more positive potential due to formation of Pu-Al alloys. The open circuit potential technique was used to identify the alloys formed. Stable deposits were obtained by potentiostatic electrolyses of LiCl-KCl-PuCl 3 melts on Al plates. XRD and SEM-EDX analyses were used to characterise the alloys, which were composed mainly of PuAl 4 with some PuAl 3. In addition, the preparation of PuCl 3 containing salt by carbochlorination of PuO 2 is described.

  12. Supercooling of aqueous NaCl and KCl solutions under acoustic levitation.

    PubMed

    Lü, Y J; Wei, B

    2006-10-14

    The supercooling capability of aqueous NaCl and KCl solutions is investigated at containerless state by using acoustic levitation method. The supercooling of water is obviously enhanced by the alkali metal ions and increases linearly with the augmentation of concentrations. Furthermore, the supercooling depends on the nature of ions and is 2-3 K larger for NaCl solution than that for KCl solution in the present concentration range: Molecular dynamics simulations are performed to reveal the intrinsic correlation between supercoolability and microstructure. The translational and orientational order parameters are applied to quantitatively demonstrate the effect of ionic concentration on the hydrogen-bond network and ice melting point. The disrupted hydrogen-bond structure determines essentially the concentration dependence of supercooling. On the other hand, the introduced acoustic pressure suppresses the increase of supercooling by promoting the growth and coalescence of microbubbles, the effective nucleation catalysts, in water. However, the dissolved ions can weaken this effect, and moreover the degree varies with the ion type. This results in the different supercoolability for NaCl and KCl solutions under the acoustic levitation conditions. PMID:17042605

  13. Supercooling of aqueous NaCl and KCl solutions under acoustic levitation.

    PubMed

    Lü, Y J; Wei, B

    2006-10-14

    The supercooling capability of aqueous NaCl and KCl solutions is investigated at containerless state by using acoustic levitation method. The supercooling of water is obviously enhanced by the alkali metal ions and increases linearly with the augmentation of concentrations. Furthermore, the supercooling depends on the nature of ions and is 2-3 K larger for NaCl solution than that for KCl solution in the present concentration range: Molecular dynamics simulations are performed to reveal the intrinsic correlation between supercoolability and microstructure. The translational and orientational order parameters are applied to quantitatively demonstrate the effect of ionic concentration on the hydrogen-bond network and ice melting point. The disrupted hydrogen-bond structure determines essentially the concentration dependence of supercooling. On the other hand, the introduced acoustic pressure suppresses the increase of supercooling by promoting the growth and coalescence of microbubbles, the effective nucleation catalysts, in water. However, the dissolved ions can weaken this effect, and moreover the degree varies with the ion type. This results in the different supercoolability for NaCl and KCl solutions under the acoustic levitation conditions.

  14. 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.

  15. 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.

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

    USGS Publications Warehouse

    Potter, Robert W.; 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.

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

    SciTech Connect

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

    2010-09-01

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

  18. 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

  19. Integrated Data Collection Analysis (IDCA) Program - KClO4/Carbon Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorensen, Daniel N.; Remmers, Daniel L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2013-01-31

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4 and activated carbon—KClO4/C mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solids. The mixture was found to be insensitive to impact, friction, and thermal stimulus, and somewhat sensitive to spark discharge. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed to develop safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. The results are compared among the laboratories and then compared to historical data from various sources. The testing performers involved for the KClO4/carbon mixture are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Indian Head Division, Naval Surface Warfare Center, (NSWC IHD), and Air Force Research Laboratory (AFRL/RXQL). These tests are conducted as a proficiency study in order to establish some consistency in test protocols, procedures, and experiments and to understand how to compare results when these testing variables cannot be made consistent.

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

    SciTech Connect

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

    2012-11-30

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

  1. Integrated Data Collection Analysis (IDCA) program--KClO4/Dodecane Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorensen, Daniel N.; Remmers, Daniel L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2012-05-11

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4 and dodecane—KClO4/dodecane mixture. This material was selected because of the challenge of performing SSST testing of a mixture of solid and liquid materials. The mixture was found to: 1) be less sensitive to impact than RDX, and PETN, 2) less sensitive to friction than RDX and PETN, and 3) less sensitive to spark than RDX and PETN. The thermal analysis showed little or no exothermic features suggesting that the dodecane volatilized at low temperatures. A prominent endothermic feature was observed and assigned to a phase transition of KClO4. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed to develop safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. The results are compared among the laboratories and then compared to historical data from various sources. The testing performers involved for the KClO4/dodecane mixture are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Indian Head Division, Naval Surface Warfare Center, (NSWC IHD), and Air Force Research Laboratory (AFRL/RXQL). These tests are conducted as a proficiency study in order to establish some

  2. 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.

  3. VizieR Online Data Catalog: ExoMol line list for KCl (Barton+, 2014)

    NASA Astrophysics Data System (ADS)

    Barton, E. J.; Chui, C.; Golpayegani, S.; Yurchenko, S. N.; Tennyson, J.; Frohman, D. J.; Bernath, P. F.

    2014-03-01

    The files comprising this line list are in the standard ExoMol format, and are named sXXkYYcl.dat and tXXkYYcl.dat, where XX and YY are the mass numbers of the potassium and chlorine isotopes, respectively. The isotopologues covered are: (39K)(35Cl), (39K)(37Cl), (41K)(35Cl) and (41K)(37Cl). The partition functions from 1-3000K in 1K intervals for these isotopologues of KCl are also provided in files named pXXkYYcl.dat and consist of two columns (T/K followed by Q). (12 data files).

  4. 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. PMID:27345810

  5. 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. PMID:27345988

  6. 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.

  7. Deposition studies of lithium and bismuth at tungsten microelectrodes in LiCl:KCl eutectic

    NASA Astrophysics Data System (ADS)

    Carlin, Richard T.; Osteryoung, Robert A.

    1989-05-01

    Tungsten microelectrodes (diam = 25 microns) have been used to study the deposition and stripping behavior of Li/Li(+) and Bi/Bi(3+) in the LiCl:KCl eutectic at 400 C. The Li deposition current can be simulated assuming the growth of a single hemisphere of liquid metal on the microelectrode. High stripping current densities were observed and quantitated using standard electrochemical equipment. An inverted microscope assembly was employed for in situ observation of the Li/Li(+) deposition and stripping processes at the microelectrode. A precipitate appears to form in the melt surrounding the electrode during Li deposition.

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

    USGS Publications Warehouse

    Potter, R.W.; 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.

  9. 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.

  10. A reactive distillation process for the treatment of LiCl-KCl eutectic waste salt containing rare earth chlorides

    NASA Astrophysics Data System (ADS)

    Eun, H. C.; Choi, J. H.; Kim, N. Y.; Lee, T. K.; Han, S. Y.; Lee, K. R.; Park, H. S.; Ahn, D. H.

    2016-11-01

    The pyrochemical process, which recovers useful resources (U/TRU metals) from used nuclear fuel using an electrochemical method, generates LiCl-KCl eutectic waste salt containing radioactive rare earth chlorides (RECl3). It is necessary to develop a simple process for the treatment of LiCl-KCl eutectic waste salt in a hot-cell facility. For this reason, a reactive distillation process using a chemical agent was achieved as a method to separate rare earths from the LiCl-KCl waste salt. Before conducting the reactive distillation, thermodynamic equilibrium behaviors of the reactions between rare earth (Nd, La, Ce, Pr) chlorides and the chemical agent (K2CO3) were predicted using software. The addition of the chemical agent was determined to separate the rare earth chlorides into an oxide form using these equilibrium results. In the reactive distillation test, the rare earth chlorides in LiCl-KCl eutectic salt were decontaminated at a decontamination factor (DF) of more than 5000, and were mainly converted into oxide (Nd2O3, CeO2, La2O3, Pr2O3) or oxychloride (LaOCl, PrOCl) forms. The LiCl-KCl was purified into a form with a very low concentration (<1 ppm) for the rare earth chlorides.

  11. 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.

  12. 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.

  13. 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.

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

    SciTech Connect

    Chen, Ken Shuang

    2009-04-01

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

  15. 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.

  16. Study of thermodynamic properties of Np-Al alloys in molten LiCl-KCl eutectic

    NASA Astrophysics Data System (ADS)

    Souček, P.; Malmbeck, R.; Mendes, E.; Nourry, C.; Sedmidubský, D.; Glatz, J.-P.

    2009-10-01

    Pyrochemical methods are investigated worldwide within the framework of Partitioning and Transmutation concepts for spent nuclear fuel reprocessing. Electroseparation techniques in a molten LiCl-KCl are being developed in ITU to recover all actinides from a mixture with fission products. During the process, actinides are selectively electrochemically reduced on a solid aluminium cathode, forming solid actinide-aluminium alloys. This work is focused on the thermodynamic properties of Np-Al alloys in a temperature range of 400-550 °C and on the characterisation of the structure and chemical composition of deposits obtained by electrodeposition of Np on solid Al electrodes in a LiCl-KCl-NpCl 3 melt. Cyclic voltammetry and open circuit chronopotentiometry have been used to examine the electrochemical behaviour of Np on inert W and reactive Al electrodes. Gibbs energies, enthalpy and entropy of formation and standard electrode potentials of Np-Al alloys were evaluated and compared with ab initio calculations. Galvanostatic electrolyses at 450 °C were carried out to recover Np onto Al plates and the solid surface deposits were characterised by XRD and SEM-EDX analyses. Stable and dense deposits consisting of NpAl 3 and NpAl 4 alloys were identified. In addition, the conversion of NpO 2 to NpCl 3 is described, using chlorination of the oxide in a molten salt media by pure chlorine gas.

  17. 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.

  18. Cyclic Corrosion and Chlorination of an FeCrAl Alloy in the Presence of KCl

    SciTech Connect

    Israelsson, Niklas; Unocic, Kinga A.; Hellström, K.; Svensson, J-E; Johansson, L-G

    2015-05-30

    The KCl-induced corrosion of the FeCrAl alloy Kanthal® APMT in an O2 + N2 + H2O environment was studied at 600 °C. The samples were pre-oxidized prior to exposure in order to investigate the protective nature of alumina scales in the present environment. The microstructure and composition of the corroded surface was investigated in detail. Corrosion started at flaws in the pre-formed α-alumina scales, i.e. α-alumina was protective in itself. Consequently, KCl-induced corrosion started locally and, subsequently, spread laterally. An electrochemical mechanism is proposed here by which a transition metal chloride forms in the alloy and K2CrO4 forms at the scale/gas interface. Scale de-cohesion is attributed to the formation of a sub-scale transition metal chloride.

  19. Single crystalline nature of para-sexiphenyl crystallites grown on KCl(100).

    PubMed

    Haber, T; Oehzelt, M; Resel, R; Andreev, A; Thierry, A; Sitter, H; Smilgies, D M; Schaffer, B; Grogger, W; Resel, R

    2006-03-01

    This work focuses on studies of the single crystal nature of para-sexiphenyl structures grown on freshly cleaved KCl(100) surfaces. Two different kinds of morphologies, namely terrace like structures and needle like structures, are found by atomic force microscopy as well as by electron microscopy. Regardless of the morphology the individual crystallites show highly regular shapes. The crystalline alignment and the degree of order of the crystallites on the surface are determined by X-ray diffraction. Several epitaxial alignments of para-sexiphenyl on KCl(100) are observed and all of them are perfectly aligned on the surface. The rocking curve widths of the organic crystallites do not exceed 800" which is approximately only the four fold of the substrates' ones. The single crystalline nature of para-sexiphenyl crystallites is proven by transmission electron microscopy, diffraction patterns, dark field imaging and high resolution techniques. Single crystalline terraced mounds reach diameters of several microns and heights of 50 nm. Single crystal needles show heights and breadths of more than 100 nm and lengths of several microns. PMID:16573123

  20. KCl-Dependent Release of Mitochondrial Membrane-Bound Arginase Appears to Be a Novel Variant of Arginase-II

    PubMed Central

    Suman, Mishra; Rajnikant, Mishra

    2016-01-01

    Arginase regulates arginine metabolism, ornithine-urea cycle, and immunological surveillance. Arginase-I is predominant in cytosol, and arginase-II is localised in the mitochondria. A mitochondrial membrane-bound arginase has also been proposed to be adsorbed with outer membrane of mitochondria which gets released by 150 mM potassium chloride (KCl). It is presumed that inclusion of 150 mM KCl in the homogenization medium would not only facilitate release of arginase bound with outer membrane of mitochondria but also affect functional anatomy of mitochondria, mitochondrial enzymes, and proteins. Therefore, it has been intended to characterize KCl-dependent release of mitochondrial membrane-bound arginase from liver of mice. Results provide advancement in the area of arginase biology and suggest that fraction of mitochondrial membrane-bound arginase contains mitochondrial arginase-II and a variant of arginase-II. PMID:27293971

  1. Comparing the antimicrobial effectiveness of NaCl and KCl with a view to salt/sodium replacement.

    PubMed

    Bidlas, Eva; Lambert, Ronald J W

    2008-05-10

    A study using a small range of pathogenic bacterial species (Aeromonas hydrophila, Enterobacter sakazakii, Shigella flexneri, Yersinia enterocolitica and 3 strains of Staphylococcus aureus) has shown that potassium chloride has an equivalent antimicrobial effect on these organisms when calculated on a molar basis. Combined NaCl and KCl experiments were carried out and data was analysed using a modification to the Lambert and Lambert [Lambert, R.J.W., and Lambert, R., 2003. A model for the efficacy of combined inhibitors. Journal of Applied Microbiology 95, 734-743.] model for combined inhibitors and showed that in combination KCl is a direct 1:1 molar replacement for the antimicrobial effect of common salt. If this is a general finding then, where salt is used to help preserve a product, partial or complete replacement by KCl is possible.

  2. 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.

  3. Growth and characterization of pure and KCl doped zinc thiourea chloride (ZTC) single crystals.

    PubMed

    Ruby Nirmala, L; Thomas Joseph Prakash, J

    2013-02-01

    Potassium Chloride (KCl) as an additive is added into zinc thiourea chloride solution in a small amount (1M%) by the method of slow evaporation solution growth technique at room temperature to get a new crystal. Due to the doping of the impurities on the crystals, remarkable changes in the physical properties were obtained. The grown crystals have been subjected to different instrumentation methods. The incorporation of the amount of potassium and zinc in the crystal lattices has been determined by AAS method. The lattice dimensions have been identified from single crystal X-ray diffraction measurements. The presence of functional group for the grown crystals has been identified by FTIR analysis. The optical, thermal and mechanical behaviors have been assessed by UV-Vis, TG/DTA and Vickers hardness methods respectively. The presence of dislocations of atoms has been identified by etching studies. PMID:23220671

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

    NASA Astrophysics Data System (ADS)

    Hosaka, Masahiro; Taki, Sadao

    1983-12-01

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

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    Kim, Si-Dong; Kim, Jung-Sik

    2006-12-01

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

  9. Calorimetric study of the entropy relation in the NaCl–KCl system

    PubMed Central

    Benisek, Artur; Dachs, Edgar

    2013-01-01

    The heat capacity of one Na-rich and two K-rich samples of the NaCl–KCl (halite–sylvite) crystalline solution was investigated between 5 and 300 K. It deviated positively from ideal behaviour with a maximum at 40 K. The thereby produced excess entropy at 298.15 K was described by a symmetric Margules mixing model yielding WmS = 8.73 J/mol/K. Using enthalpy of mixing data from the literature and our data on the entropy, the solvus was calculated for a pressure of 105 Pa and compared with the directly determined solvus. The difference between them can be attributed to the effect of Na–K short range ordering (clustering). PMID:24926102

  10. Calorimetric study of the entropy relation in the NaCl-KCl system.

    PubMed

    Benisek, Artur; Dachs, Edgar

    2013-07-01

    The heat capacity of one Na-rich and two K-rich samples of the NaCl-KCl (halite-sylvite) crystalline solution was investigated between 5 and 300 K. It deviated positively from ideal behaviour with a maximum at 40 K. The thereby produced excess entropy at 298.15 K was described by a symmetric Margules mixing model yielding [Formula: see text] = 8.73 J/mol/K. Using enthalpy of mixing data from the literature and our data on the entropy, the solvus was calculated for a pressure of 10(5) Pa and compared with the directly determined solvus. The difference between them can be attributed to the effect of Na-K short range ordering (clustering).

  11. 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.

  12. 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.

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

    SciTech Connect

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

    2006-07-14

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

  14. Determination of the refractive index difference caused by the birefringence of FA (II) centers in KCl:Li

    NASA Astrophysics Data System (ADS)

    Silfsten, Pertti; Ketolainen, Pertti

    1991-11-01

    A method is described for determining the refractive index difference caused by the birefringence of oriented FA (II) centers in KCl:Li crystals. It is shown that the portion induced by the birefringence can be separated from an absorption spectrum measured through a polarizer-analyzer system. From this portion the refractive index difference can then be calculated with ease.

  15. Electrochemical extraction of neodymium by co-reduction with aluminum in LiCl-KCl molten salt

    NASA Astrophysics Data System (ADS)

    Yan, Yong-De; Xu, Yan-Lu; Zhang, Mi-Lin; Xue, Yun; Han, Wei; Huang, Ying; Chen, Qiong; Zhang, Zhi-Jian

    2013-02-01

    The electrochemical behavior of Nd(III) ions in LiCl-KCl and LiCl-KCl-AlCl3 melts on a Mo electrode at 723 K was studied by various electrochemical techniques. The results showed that Nd(III) ions are reduced to Nd(0) through two consecutive steps, and the underpotential deposition of neodymium on pre-deposited Al electrode formed two kinds of Al-Nd intermetallic compounds in LiCl-KCl-AlCl3 solutions. The electrochemical extraction of neodymium was carried out in LiCl-KCl-AlCl3 melts on a Mo electrode at 873 K by potentiostatic and galvanostatic electrolysis. The extraction efficiency was 99.25% after potentiostatic electrolysis for 30 h. Al-Li-Nd bulk alloy was obtained by galvanostatic electrolysis. X-ray diffraction (XRD) suggested that Al2Nd and Al3Nd phases were formed in Al-Li-Nd alloy. The microstructure and micro-zone chemical analysis of Al-Li-Nd alloy were characterized by scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), respectively.

  16. Cytosolic protein concentration is the primary volume signal for swelling-induced [K-Cl] cotransport in dog red cells

    PubMed Central

    1992-01-01

    Chloride-dependent K transport ([K-Cl] cotransport) in dog red cells is activated by cell swelling. Whether the volume signal is generated by a change in cell configuration or by the dilution of some cytosolic constituent is not known. To differentiate between these two alternatives we prepared resealed ghosts that, compared with intact red cells, had the same surface area and similar hemoglobin concentration, but a greatly diminished volume. Swelling-induced [K-Cl] cotransport was activated in the ghosts at a volume (20 fl) well below the activation volume for intact cells (70 fl), but at a similar hemoglobin concentration (30-35 g dry solids per 100 g wet weight). Ghosts made to contain 40% albumin and 60% hemoglobin showed activation of [K-Cl] cotransport at a concentration of cell solids similar to intact cells or ghosts containing only hemoglobin. [K-Cl] cotransport in the resealed ghosts became quiescent at a dry solid concentration close to that at which shrinkage-induced Na/H exchange became activated. These results support the notion that the primary volume sensor in dog red cells is cytosolic protein concentration. We speculate that macromolecular crowding is the mechanism by which cells initiate responses to volume perturbation. PMID:1512553

  17. 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.

  18. Uncertainties of Gaseous Oxidized Mercury Measurements Using KCl-Coated Denuders, Cation-Exchange Membranes, and Nylon Membranes: Humidity Influences.

    PubMed

    Huang, Jiaoyan; Gustin, Mae Sexauer

    2015-05-19

    Quantifying the concentration of gaseous oxidized mercury (GOM) and identifying the chemical compounds in the atmosphere are important for developing accurate local, regional, and global biogeochemical cycles. The major hypothesis driving this work was that relative humidity affects collection of GOM on KCl-coated denuders and nylon membranes, both currently being applied to measure GOM. Using a laboratory manifold system and ambient air, GOM capture efficiency on 3 different collection surfaces, including KCl-coated denuders, nylon membranes, and cation-exchange membranes, was investigated at relative humidity ranging from 25 to 75%. Recovery of permeated HgBr2 on KCl-coated denuders declined by 4-60% during spikes of relative humidity (25 to 75%). When spikes were turned off GOM recoveries returned to 60 ± 19% of permeated levels. In some cases, KCl-coated denuders were gradually passivated over time after additional humidity was applied. In this study, GOM recovery on nylon membranes decreased with high humidity and ozone concentrations. However, additional humidity enhanced GOM recovery on cation-exchange membranes. In addition, reduction and oxidation of elemental mercury during experiments was observed. The findings in this study can help to explain field observations in previous studies.

  19. 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

  20. 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.

  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.

  2. 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.

  3. Chemical stability of solutions of niobium V in molten NaCl-KCl at 750 C

    SciTech Connect

    Arurault, L.; Poignet, J.C. ); Bouteillon, J. Univ. Joseph Fourier, Grenoble )

    1995-01-01

    Recently, niobium metal has raised much interest because of its good properties in nuclear technology, electronics, metallurgy, and possibly superconductors. The necessity, for most of these uses, to have highly pure niobium explains why research started in the early sixties for obtaining this metal by molten salt electrolysis as an alternative process to thermal reduction. Solutions of Nb(V), mainly as K[sub 2]NbF[sub 7], in molten NaCl-KCl at 750 C, were studied by potentiometry, linear sweep voltammetry, chemical and X-ray analysis. Voltammograms at tungsten electrodes showed that the use of silica parts in contact with the melt had to be strictly discarded. The variations of the open-circuit potentials of tungsten or vitreous carbon electrodes, recorded during several weeks, showed that the Nb(V) species was not stable and underwent slow reduction to Nb(IV). This hypothesis was reinforced by chemical and X-ray analysis of the frozen melts. Reduction of Nb(V) to Nb(IV) was fast and complete when niobium metal was introduced in the melt.

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

    SciTech Connect

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

    2011-06-15

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

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

    NASA Astrophysics Data System (ADS)

    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.

  6. 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.

  7. Integrated Data Collection Analysis (IDCA) Program — KClO3/Icing Sugar (-100 mesh) Mixture

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorenson, Daniel N.; Remmers, Daniel L.; Moran, Jesse S.; Shelley, Timothy J.; Hsu, Peter C.; Whipple, Richard E.; Reynolds, John G.

    2011-05-02

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and scanning calorimetry analysis of a mixture of KClO3 sized through a 100-mesh sieve mixed with icing sugar, also sized through a 100-mesh sieve—KClO3/icing sugar (-100) mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solid materials. The mixture was found to be: 1) more sensitive to impact than RDX, with sensitivity similar to PETN, 2) the same or more sensitive to friction than PETN, and 3) less sensitive to spark than RDX. The analysis showed that the mixture has thermally stability similar to RDX and is perhaps more energetic upon decomposition but variable results indicate sampling issues.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    SciTech Connect

    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. 16 references, 7 figures, 1 table.

  10. 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.

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

    PubMed Central

    1995-01-01

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

  12. Decomposition of di-tert-butyl peroxide on the surface of KCl/SiO/sub 2/

    SciTech Connect

    Chaltykyan, M.T.; Lazarev, E.G.; Aliev, R.K.; Gazaryan, K.G.; Garibyan, T.A.; Nalbandyan, A.B.; Gencheva, L.; Kotsev, N.K.; Shopov, D.M.

    1989-02-01

    A study was carried out on carbon deposition on the surface of 5% KCl/SiO/sub 2/ upon the decomposition of di-tert-butyl peroxide, (DTBP). The EPR spectra of the paramagnetic sites in the carbon deposit depend on the amount of peroxide decomposed. The EPR spectrum of the RO/sub 2/ radicals stabilized on KCl crystals was recorded. Carbonization of the surface as a result of the decomposition of DTBP is responsible for the chemical reactions, including the reactions of adsorbed RO/sub 2/ radicals, the formation of carbon deposits with strongly delocalized electrons in the conductance band, and the reaction of the radicals with localized paramagnetic sites, which should hinder the removal of the radicals from the surface into the gas phase.

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

    PubMed

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

    2016-03-01

    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. PMID:27345970

  14. 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. PMID:27345970

  15. Integrated Data Collection Analysis (IDCA) Program — KClO3 (as received)/Icing Sugar

    SciTech Connect

    Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.; Pollard, Colin J.; Warner, Kirstin F.; Sorenson, Daniel N.; Remmers, Daniel L.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Whipple, Richard E.; Reynolds, John G.

    2011-05-23

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO3 as received from the manufacturer mixed with icing sugar, sized through a 100-mesh sieve—KClO3/icing sugar (AR) mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solid materials. The mixture was found to: 1) be more sensitive to impact than RDX, similar to PETN, 2) be the same or less sensitive to friction than PETN, and 3) to be less sensitive to spark than RDX. The thermal analysis showed that the mixture has thermally stability similar to RDX and is perhaps more energetic upon decomposition but variable results indicate sampling issues. Compared to the 100-mesh sieved counter part, the KClO3/icing sugar (-100) mixture, the AR mixture was found to be about the same sensitivity towards impact, friction and ESD.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Boron removal and recovery from concentrated wastewater using a microwave hydrothermal method.

    PubMed

    Tsai, Hao-Cheng; Lo, Shang-Lien

    2011-02-28

    Boron compounds are widely-used raw materials in industries. However, elevated boron concentrations in aqueous systems may be harmful to human and plants. In this study, calcium hydroxide (Ca(OH)(2)) alone and Ca(OH)(2) with phosphoric acid (H(3)PO(4)) addition (P-addition) were used to remove and recover boron from wastewater using hydrothermal methods. A microwave (MW) hydrothermal method was used and compared with the conventional heating (CH) method in batch experiments. Physicochemical properties of the precipitates obtained from both methods were analysed by XRD, SEM with EDX and BET. For the case of Ca(OH)(2) alone and the MW method, experimental results showed that boron recovery efficiency reached 90% within 10 min, and crystals of Ca(2)B(2)O(5)·H(2)O were found in the precipitates as indicated by the XRD analysis. For the case of P-addition and the MW method, boron recovery efficiency reached 99% within 10 min, and calcium phosphate species (CaHPO(4)·H(2)O, CaHPO(4) and Ca(10)(PO(4))(6)(OH)(2)) were formed. The experimental results of this study indicate that the required reaction time of the MW method was much less than that of the CH method, and the MW method is an effective and efficient method for boron removal and recovery from concentrated wastewater.

  1. Boron removal and recovery from concentrated wastewater using a microwave hydrothermal method.

    PubMed

    Tsai, Hao-Cheng; Lo, Shang-Lien

    2011-02-28

    Boron compounds are widely-used raw materials in industries. However, elevated boron concentrations in aqueous systems may be harmful to human and plants. In this study, calcium hydroxide (Ca(OH)(2)) alone and Ca(OH)(2) with phosphoric acid (H(3)PO(4)) addition (P-addition) were used to remove and recover boron from wastewater using hydrothermal methods. A microwave (MW) hydrothermal method was used and compared with the conventional heating (CH) method in batch experiments. Physicochemical properties of the precipitates obtained from both methods were analysed by XRD, SEM with EDX and BET. For the case of Ca(OH)(2) alone and the MW method, experimental results showed that boron recovery efficiency reached 90% within 10 min, and crystals of Ca(2)B(2)O(5)·H(2)O were found in the precipitates as indicated by the XRD analysis. For the case of P-addition and the MW method, boron recovery efficiency reached 99% within 10 min, and calcium phosphate species (CaHPO(4)·H(2)O, CaHPO(4) and Ca(10)(PO(4))(6)(OH)(2)) were formed. The experimental results of this study indicate that the required reaction time of the MW method was much less than that of the CH method, and the MW method is an effective and efficient method for boron removal and recovery from concentrated wastewater. PMID:21211905

  2. 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.

  3. 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.

  4. Direct measurement of translingual epithelial NaCl and KCl currents during the chorda tympani taste response.

    PubMed Central

    Heck, G L; Persaud, K C; DeSimone, J A

    1989-01-01

    We have measured the NaCl or KCl currents under voltage clamp across the dorsal lingual epithelium of the rat and simultaneously the response of the taste nerves. Under short-circuit conditions a NaCl stimulus evoked an inward current (first current) that coincided with excitation of the chorda tympani. This was followed by a slower inward current (second current) that matched the kinetics of taste nerve adaptation. The peak first current and the coincident neural response satisfied the same saturating NaCl concentration dependence. Both first and second currents were partially blocked by amiloride as were the phasic and tonic components of the neural response. The NaCl-evoked second current was completely blocked by ouabain. Investigation of the NaCl-evoked current and the neural response over a range of clamped voltages showed that inward negative potentials enhanced the inward current and the neural response to 0.3 M NaCl. Sufficiently high inward positive potentials reversed the current, and made the neural response independent of further changes in voltage. Therefore, one of the NaCl taste transduction mechanisms is voltage dependent while the other is voltage independent. A KCl stimulus also evoked an inward short-circuit current, but this and the neural response were not amiloride-sensitive. The data indicate that neural adaptation to a NaCl stimulus, but not a KCl stimulus, is mediated by cell Na/K pumps. A model is proposed in which the connection between the NaCl-evoked second current and cell repolarization is demonstrated. PMID:2541822

  5. 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.

  6. 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)

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

    SciTech Connect

    Higa, Mitsuru; Kira, Akira

    1995-04-06

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

  8. 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. PMID:27346000

  9. 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. PMID:27345982

  10. 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. PMID:27345980

  11. 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. PMID:27345977

  12. 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. PMID:27345987

  13. 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. PMID:27345783

  14. 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. PMID:27345979

  15. 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. PMID:27345983

  16. 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. PMID:27345978

  17. 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. PMID:27346001

  18. 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. PMID:27345975

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

    PubMed

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

    2016-03-01

    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+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. PMID:27345980

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

    PubMed

    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. PMID:27345783

  1. Organic-inorganic interaction between hydroxyapatite and gelatin with the aging of gelatin in aqueous phosphoric acid solution.

    PubMed

    Chang, Myung Chul

    2008-11-01

    Hydroxyapatite (HAp)/gelatin (GEL) nanocomposite was prepared by the solution-precipitation process using Ca(OH)(2) in water and aqueous solution of H(3)PO(4) in GEL. Before the co precipitation process the GEL powders were dissolved in the aqueous phosphoric acid solution for the phosphorylation of GEL molecules. The chemical variation of the phosphorylated GEL macromolecules was investigated by using attenuated total reflection (ATR) measurement. The crystal growth of HAp became bigger with the long-time aging of the GEL molecules in the phosphoric acid solution, and it resulted from the reduction of length scale of the GEL molecules. The degree of the organic-inorganic interaction was decreased because of the degradation of the GEL macromolecules.

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

    NASA Astrophysics Data System (ADS)

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

    1980-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  4. 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.

  5. 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.

  6. A mechanism of mineral replacement: isotope tracing in the model system KCl-KBr-H 2O

    NASA Astrophysics Data System (ADS)

    Putnis, Christine V.; Mezger, Klaus

    2004-07-01

    The solid solution-aqueous solution system KCl-KBr-H 2O is used as a model system to determine the mechanism of the replacement process of one crystalline phase by another. A single crystal of KBr was allowed to react with a saturated KCl solution enriched in 40K and the resulting new product phases were analyzed for changes in both anion and K isotope composition, using SEM, EDX, microprobe analysis, mass spectrometry and X-ray diffraction. The results show that the new product, K(Cl,Br), contains elements derived from both the original fluid and solid phases, indicating that both anions and K isotopes are exchanged during the replacement reaction. The interface between the advancing reaction front and the original parent crystal is sharp on a micron scale, showing no reaction profile that could indicate a solid state diffusion mechanism. Macroscopically the new phase is turbid due to the development of porosity that is consistent with a net volume deficit replacement reaction and this porosity may act as an indication that a replacement process has taken place. Single crystal X-ray diffraction patterns show the preservation of the crystallographic orientation during the replacement process. The replacement mechanism is interpreted as a result of a coupled process of dissolution and recrystallization occurring at the fluid-crystal interface.

  7. 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

  8. Effects of temperature, concentration, and uranium chloride mixture on zirconium electrochemical studies in LiClsbnd KCl eutectic salt

    NASA Astrophysics Data System (ADS)

    Hoover, Robert O.; Yoon, Dalsung; Phongikaroon, Supathorn

    2016-08-01

    Experimental studies were performed to provide measurement and analysis of zirconium (Zr) electrochemistry in LiClsbnd KCl eutectic salt at different temperatures and concentrations using cyclic voltammetry (CV). An additional experimental set with uranium chloride added into the system forming UCl3sbnd ZrCl4sbnd LiClsbnd KCl was performed to explore the general behavior of these two species together. Results of CV experiments with ZrCl4 show complicated cathodic and anodic peaks, which were identified along with the Zr reactions. The CV results reveal that diffusion coefficients (D) of ZrCl4 and ZrCl2 as the function of temperature can be expressed as DZr(IV) = 0.00046exp(-3716/T) and DZr(II) = 0.027exp(-5617/T), respectively. The standard rate constants and apparent standard potentials of ZrCl4 at different temperatures were calculated. Furthermore, the results from the mixture of UCl3 and ZrCl4 indicate that high concentrations of UCl3 hide the features of the smaller concentration of ZrCl4 while Zr peaks become prominent as the concentration of ZrCl4 increases.

  9. Comparison of gaseous oxidized Hg measured by KCl-coated denuders, and nylon and cation exchange membranes.

    PubMed

    Huang, Jiaoyan; Miller, Matthieu B; Weiss-Penzias, Peter; Gustin, Mae Sexauer

    2013-07-01

    The chemical compounds that make up gaseous oxidized mercury (GOM) in the atmosphere, and the reactions responsible for their formation, are not well understood. The limitations and uncertainties associated with the current method applied to measure these compounds, the KCl-coated denuder, are not known due to lack of calibration and testing. This study systematically compared the uptake of specific GOM compounds by KCl-coated denuders with that collected using nylon and cation exchange membranes in the laboratory and field. In addition, a new method for identifying different GOM compounds using thermal desorption is presented. Different GOM compounds (HgCl2, HgBr2, and HgO) were found to have different affinities for the denuder surface and the denuder underestimated each of these compounds. Membranes measured 1.3 to 3.7 times higher GOM than denuders in laboratory and field experiments. Cation exchange membranes had the highest collection efficiency. Thermodesorption profiles for the release of GOM compounds from the nylon membrane were different for HgO versus HgBr2 and HgCl2. Application of the new field method for collection and identification of GOM compounds demonstrated these vary as a function of location and time of year. Understanding the chemistry of GOM across space and time has important implications for those developing policy regarding this environmental contaminant. PMID:23651121

  10. Statistical hadronization model analysis of hadron yields in p + Nb and Ar + KCl at SIS18 energies

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    The HADES data from p + Nb collisions at a center-of-mass energy of √{s_{NN}} = 3.2 GeV are analyzed employing a statistical hadronization model. The model can successfully describe the production yields of the identified hadrons π0, η, Λ, K 0 s, ω with parameters T_{chem} = (99± 11) MeV and μb = (619± 34) MeV, which fit well into the chemical freeze-out systematics found in heavy-ion collisions. In addition, we reanalyze our previous HADES data from Ar + KCl collisions at √{s_{NN}} = 2.6 GeV with an updated version of the model. We address equilibration in heavy-ion collisions by testing two aspects: the description of yields and the regularity of freeze-out parameters from a statistical model fit as a function of colliding energy and system size. Despite its success, the model fails to describe the observed Ξ- yields in both, p + Nb and Ar + KCl . Special emphasis is put on feed-down contributions from higher-lying resonance states as a possible explanation for the observed excess.

  11. Physical and chemical modification of distillery sludge for Pb(II) biosorption.

    PubMed

    Nadeem, Raziya; Hanif, Muhammad Asif; Shaheen, Fatima; Perveen, Shahnaz; Zafar, Muhammad Nadeem; Iqbal, Tahira

    2008-01-31

    The waste distillery sludge from sugar-cane industry was pretreated physically (boiled, heated and autoclaved) as well as chemically (HCl, H(2)SO(4), H(3)PO(4), NaOH, Ca(OH)(2), Al(OH)(3), C(6)H(6), HCHO, CH(3)OH and C1(2)H(25)OSO(3)Na (sodium dodecyl sulphate (SDS)) for assessing the comparative sorption capacity of untreated and modified distillery sludge for Pb(II) biosorption from aqueous solutions. Experiments were conducted in shake flasks on a batch basis to access the effect of different experimental parameters such as pH, biosorbent dosage, biosorbent size, initial Pb(II) concentration and contact time. The uptake capacity 'q' (mg/g) of untreated and pretreated distillery sludge was in following order: NaOH (51.29+/-1.21)>HCl (49.82+/-1.22)>HCHO (49.56+/-1.14)>H(2)SO(4) (47.71+/-1.20)>HgCl(2) (45.32+/-1.06)>Ca(OH)(2) (44.01+/-1.18)>MeOH (43.73+/-1.23)>C(6)H(6) (42.72+/-1.19)>H(3)PO(4) (42.01+/-1.17)>SDS (40.87+/-1.27)>autoclaved (40.23+/-1.24)>Boiled (39.95+/-1.19)>heated (38.87+/-1.32)>Al (OH)(3) (38.30+/-1.14)>untreated (37.76+/-1.21). In further parameter studies, the optimized biosorbent size was 0.250 mm at pH 5 and best dose was 0.05 g of biosorbent. The applicability of the Langmuir and Freundlich models for sorption process was tested and best fitted model was Langmuir with the coefficient of determination (R(2)) value, 0.97, the process followed second order kinetic mechanism.

  12. 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

  13. The Frequency of Calcium Oscillations Induced by 5-HT, ACH, and KCl Determine the Contraction of Smooth Muscle Cells of Intrapulmonary Bronchioles

    PubMed Central

    Perez, Jose F.; Sanderson, Michael J.

    2005-01-01

    Increased resistance of airways or blood vessels within the lung is associated with asthma or pulmonary hypertension and results from contraction of smooth muscle cells (SMCs). To study the mechanisms regulating these contractions, we developed a mouse lung slice preparation containing bronchioles and arterioles and used phase-contrast and confocal microscopy to correlate the contractile responses with changes in [Ca2+]i of the SMCs. The airways are the focus of this study. The agonists, 5-hydroxytrypamine (5-HT) and acetylcholine (ACH) induced a concentration-dependent contraction of the airways. High concentrations of KCl induced twitching of the airway SMCs but had little effect on airway size. 5-HT and ACH induced asynchronous oscillations in [Ca2+]i that propagated as Ca2+ waves within the airway SMCs. The frequency of the Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained airway contraction. In the absence of extracellular Ca2+ or in the presence of Ni2+, the frequency of the Ca2+ oscillations declined and the airway relaxed. By contrast, KCl induced low frequency Ca2+ oscillations that were associated with SMC twitching. Each KCl-induced Ca2+ oscillation consisted of a large Ca2+ wave that was preceded by multiple localized Ca2+ transients. KCl-induced responses were resistant to neurotransmitter blockers but were abolished by Ni2+ or nifedipine and the absence of extracellular Ca2+. Caffeine abolished the contractile effects of 5-HT, ACH, and KCl. These results indicate that (a) 5-HT and ACH induce airway SMC contraction by initiating Ca2+ oscillations, (b) KCl induces Ca2+ transients and twitching by overloading and releasing Ca2+ from intracellular stores, (c) a sustained, Ni2+-sensitive, influx of Ca2+ mediates the refilling of stores to maintain Ca2+ oscillations and, in turn, SMC contraction, and (d) the magnitude of sustained airway SMC contraction is regulated by the frequency of Ca2+ oscillations

  14. 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.

    1980-08-01

    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.

  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

  16. 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

  17. 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

  18. Hydration numbers of ions in aqueous solutions of KOH, KCl, KI, and KIO3 according to refractometric data

    NASA Astrophysics Data System (ADS)

    Masimov, E. A.; Abbasov, H. F.

    2013-08-01

    Ion hydration in aqueous solutions of KOH, KCl, KI, and KIO3 was studied by refractometry. The sum of the hydration numbers of the potassium ion and each anion in these compounds and the hydration numbers of OH-, Cl-, I-, and IO{3/-} anions were determined by the Lorentz-Lorenz equation at different salt concentrations. The model suggests that the polarizability of the hydrated ion is proportional to the cube of the ion radius and the volume of the hydrated ion equals the sum of the nonhydated ion and hydration shell volumes. The hydration numbers of the anions calculated by the proposed procedure increase with their radii in the sequence: OH-, Cl-, I-, and IO{3/-}.

  19. 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.

  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. 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. PMID:27345811

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

    PubMed

    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.814T>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. PMID:27345811

  3. 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.

  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. 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

  6. 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.

  7. Effect of partial substitution of NaCl with KCl on Halloumi cheese during storage: chemical composition, lactic bacterial count, and organic acids production.

    PubMed

    Ayyash, Mutamed M; Shah, Nagendra P

    2010-08-01

    The effect of partial substitution of NaCl with KCl on chemical composition, lactic bacterial count, and organic acids profile of Halloumi cheese was investigated. Halloumi cheeses were made and kept in 4 different brine solutions at 18% including NaCl only (HA), 3NaCl : 1KCl (HB), 1NaCl : 1KCl (HC), and 1NaCl : 3KCl (HD) and then stored at 4 degrees C for 56 d. No significant effect was observed between control and experimental cheeses in terms of moisture, fat, protein, lactic bacterial count, and pH values at the same storage period. There was a significant difference in ash, sodium, and potassium contents among experimental cheeses at the same storage period. Ash, sodium, and potassium contents increased significantly during storage at same salt treatment. There was no significant difference in lactic and citric acid contents among experimental cheeses and that of the control. In contrary, there was a significant difference in acetic acid among experimental cheeses. A strong positive correlation was observed between ash, Na, and K contents. An inverse correlation between organic acids and both Na and K contents was also observed.

  8. 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.

  9. 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

  10. Role of the neuronal K-Cl co-transporter KCC2 in inhibitory and excitatory neurotransmission

    PubMed Central

    Chamma, Ingrid; Chevy, Quentin; Poncer, Jean Christophe; Lévi, Sabine

    2012-01-01

    The K-Cl co-transporter KCC2 plays multiple roles in the physiology of central neurons and alterations of its function and/or expression are associated with several neurological conditions. By regulating intraneuronal chloride homeostasis, KCC2 strongly influences the efficacy and polarity of the chloride-permeable γ-aminobutyric acid (GABA) type A and glycine receptor (GlyR) mediated synaptic transmission. This appears particularly critical for the development of neuronal circuits as well as for the dynamic control of GABA and glycine signaling in mature networks. The activity of the transporter is also associated with transmembrane water fluxes which compensate solute fluxes associated with synaptic activity. Finally, KCC2 interaction with the actin cytoskeleton appears critical both for dendritic spine morphogenesis and the maintenance of glutamatergic synapses. In light of the pivotal role of KCC2 in the maturation and function of central synapses, it is of particular importance to understand the cellular and molecular mechanisms underlying its regulation. These include development and activity-dependent modifications both at the transcriptional and post-translational levels. We emphasize the importance of post-translational mechanisms such as phosphorylation and dephosphorylation, oligomerization, cell surface stability, clustering and membrane diffusion for the rapid and dynamic regulation of KCC2 function. PMID:22363264

  11. Stoichiometric saturation tests of NaCl1- xBrx and KCl1- xBrx

    NASA Astrophysics Data System (ADS)

    Stoessell, Ronald K.; Carpenter, Alden B.

    1986-07-01

    Stoichiometric saturation is examined as a possible control on Br contents of halite and sylvite during precipitation from binary salt solutions of NaCl-NaBr and KCl-KBr, respectively. Experimental data at 25°C, assumed to represent Stoichiometric saturation, were used to predict mole fractions of NaBr in halite and KBr in sylvite in thermodynamic equilibrium with fluids as a function of aqueous activity ratios of Br -:Cl -. The predictions are based on the additional assumption that the aqueous activity product of the major salt component in the precipitated salt was independent of the trace Br content in the salt lattice. The extension of the predictions to diagenetic pressures and temperatures is discussed. The predicted equilibrium Br content of halite at initial halite saturation of evaporating seawater is in close agreement with that computed from the distribution coefficient of Lutz (1975), measured in slowgrowth single crystal experiments. Fluid recrystallization of halite and sylvite at near-surface temperatures is predicted to generally deplete the Br contents in the solids. Bulk Br contents in halite in cap-rock of Gulf Coast salt domes generally agree with those predicted by the recrystallization of halite in the presence of evaporative-concentrated seawater. At a constant solution composition, increasing temperature results in increasing the equilibrium Br content of halite, making less efficient Br depletion in halite by recrystallization.

  12. Compatibility of ZrN and HfN with molten LiCl-KCl-NaCl-UCl 3

    NASA Astrophysics Data System (ADS)

    Periasamy, Prakash; Hurley, Michael F.; Marx, Brian M.; Simpson, Michael F.; Butt, Darryl P.

    2010-10-01

    The reaction kinetics of ZrN and HfN immersed in a quaternary salt of composition of 28.5% LiCl-36.3% KCl-29.4% NaCl-5.8% UCl 3 (in weight percent) were assessed. Coupons of ZrN and HfN were exposed to the quaternary salt at 525-900 °C for 4-485 h. The reaction kinetics of the salt-refractory interactions were assessed through physical and microstructural characterization including scanning electron microscopy, X-ray diffraction and mass spectrometry. The results indicated that ZrN and HfN lose weight under all conditions investigated. While multiple mechanisms were evident, it is proposed that dissolution and oxidation were the dominant reactions that influence the weight loss. For the overall reaction, negative apparent activation energy values of -46 and -28 kJ/mol were observed in ZrN and HfN, respectively. These seemingly anomalous activation energies were associated with the simultaneous occurrence of electrochemical dissolution and surface oxide formation.

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

    SciTech Connect

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

    2010-08-15

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

  14. 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.

  15. 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

  16. Neurogenic mechanisms contribute to hypertension in mice with disruption of the K-Cl cotransporter KCC3.

    PubMed

    Rust, Marco B; Faulhaber, Jörg; Budack, Mareike K; Pfeffer, Carsten; Maritzen, Tanja; Didié, Michael; Beck, Franz-Xaver; Boettger, Thomas; Schubert, Rudolf; Ehmke, Heimo; Jentsch, Thomas J; Hübner, Christian A

    2006-03-01

    The neurodegenerative disorder Andermann syndrome is caused by mutations of the K-Cl cotransporter KCC3. Mice with a targeted disruption of the corresponding gene, Slc12a6, reproduce neurodegeneration of the peripheral and central nervous system (CNS) and display arterial hypertension. Kcc3 is expressed in numerous tissues, including the CNS and vascular smooth muscle cells. As the intracellular chloride concentration may influence myogenic tone and hence blood pressure, we measured the chloride concentration in vascular smooth muscle cells. It was indeed increased in superficial brain arteries and saphenous arteries of Kcc3(-/-) mice. Isolated saphenous arteries and their third-order branches, however, reacted indistinguishably to changes in intravascular pressure, stimulation of alpha1-adrenoreceptors, exogenous nitric oxide, or blockade of calcium-activated chloride channels. Likewise, the responses to alpha1-adrenergic stimulation or exogenous nitric oxide in vivo were identical in both genotypes. These results argue against a major vascular-intrinsic component of arterial hypertension in Kcc3(-/-) mice. In contrast, either alpha1-adrenergic blockade or inhibition of ganglionic transmission abolished the difference in arterial blood pressure between both genotypes. This demonstrates a neurogenic component in the maintenance of this phenotype, which is further supported by an increase of urinary norepinephrine and epinephrine excretion in Kcc3(-/-) mice. Our data indicate that local control of myogenic tone does not require KCC3 and that hypertension in Kcc3(-/-) mice depends on an elevated sympathetic tone.

  17. With no lysine L-WNK1 isoforms are negative regulators of the K+-Cl- cotransporters.

    PubMed

    Mercado, Adriana; de Los Heros, Paola; Melo, Zesergio; Chávez-Canales, María; Murillo-de-Ozores, Adrián R; Moreno, Erika; Bazúa-Valenti, Silvana; Vázquez, Norma; Hadchouel, Juliette; Gamba, Gerardo

    2016-07-01

    The K(+)-Cl(-) cotransporters (KCC1-KCC4) encompass a branch of the SLC12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. L-WNK1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoaldosteronism type II (PHAII) and the neurological disease hereditary sensory neuropathy 2 (HSN2). The effect of L-WNK1 on KCC activity is unknown. Using Xenopus laevis oocytes and HEK-293 cells, we show that the activation of KCCs by cell swelling was prevented by L-WNK1 coexpression. In contrast, the activity of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 was remarkably increased with L-WNK1 coexpression. The negative effect of L-WNK1 on the KCCs is kinase dependent. Elimination of the STE20 proline-alanine rich kinase (SPAK)/oxidative stress-responsive kinase (OSR1) binding site or the HQ motif required for the WNK-WNK interaction prevented the effect of L-WNK1 on KCCs, suggesting a required interaction between L-WNK1 molecules and SPAK. Together, our data support that NKCC1 and KCCs are coordinately regulated by L-WNK1 isoforms.

  18. Range effects of the Coulombic forces on structures, thermodynamic properties and potential energy landscapes: (KCl)32 and related systems

    NASA Astrophysics Data System (ADS)

    Wang, Chengju; Stephen Berry, R.; Jellinek, Julius

    2012-05-01

    By introducing two shielding parameters into the Coulombic part of the Coulomb plus Born-Mayer potential originally developed for (KCl)n systems, we study the effects of the range of the Coulombic interactions on the structures, thermodynamic properties and the potential energy landscapes of binary ionically bonded systems as illustrated by the case of n = 32. Our calculations show that shortening of the Coulomb interaction range leads to a decrease in the energy of the most stable structure, and the structure itself changes from the rocksalt cubic to a hollow cage type. The energy range, in which the heat capacity exhibits a negative value, gradually narrows and eventually disappears. The number of stationary points on the potential energy surface increases, and their energies get spread over a larger interval. The extent of the Coulombic interaction also affects the energy difference (gap) between the most stable structure and the structure that follows it. All these changes translate into changes in the melting behavior of the system. An analysis of the melting behavior as a function of the range of the Coulombic interaction is presented and correlated with the range-dependent changes in the topography of the underlying potential energy surface.

  19. Phase relationships in positive electrodes of high temperature Li-Al/LiCl-KCl/FeS2 cells

    NASA Astrophysics Data System (ADS)

    Tomczuk, Z.; Tani, B.; Otto, N. C.; Roche, M. F.; Vissers, D. R.

    1982-05-01

    The phases present in FeS2 electrodes operated in LiCl-KCl eutectic electrolyte are determined by X-ray diffraction and metallographic examination. The phases are FeS2, KFeS2, Li3Fe2S4, Li2.33Fe0.67S2, Fe/1-x/S, Li2FeS2, LiK6Fe24S26Cl, Li2S, and Fe. The metallographic and crystallographic characteristics of these phases are given. The sequence of Li-Fe-S phases in the FeS2 electrode is found to be in accord with the sequence predicted from the equilibrium LiFe-S phase diagram. It is noted that two of the Li-Fe-S phases found at room temperature (Li2.33Fe0.67S2 and Li2FeS2) result from decomposition on cooling of a solid solution phase: Li/2+x/Fe/1-x/S2, x ranging from 0 to 0.33.

  20. Estimation of the composition of intermetallic compounds in LiCl-KCl molten salt by cyclic voltammetry.

    PubMed

    Liu, Ya L; Liu, Kui; Yuan, Li Y; Chai, Zhi F; Shi, Wei Q

    2016-08-15

    In this work, the compositions of Ce-Al, Er-Al and La-Bi intermetallic compounds were estimated by the cyclic voltammetry (CV) technique. At first, CV measurements were carried out at different reverse potentials to study the co-reduction processes of Ce-Al, Er-Al and La-Bi systems. The CV curves obtained were then re-plotted with the current as a function of time, and the coulomb number of each peak was calculated. By comparing the coulomb number of the related peaks, the compositions of the Ce-Al, Er-Al and La-Bi intermetallic compounds formed in the co-reduction process could be estimated. The results showed that Al11Ce3, Al3Ce, Al2Ce and AlCe could be formed by the co-reduction of Ce(iii) and Al(iii). For the co-reduction of Er(iii) and Al(iii), Al3Er2, Al2Er and AlEr were formed. In a La(iii) and Bi(iii) co-existing system in LiCl-KCl melts, LaBi2, LaBi and Li3Bi were the major products as a result of co-reduction.

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

    NASA Astrophysics Data System (ADS)

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

    1989-10-01

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

  2. A Microstructural and Kinetic Investigation of the KCl-Induced Corrosion of an FeCrAl Alloy at 600 °C

    DOE PAGESBeta

    Israelsson, Niklas; Unocic, Kinga A.; Hellström, K.; Jonsson, T.; Norell, M.; Svensson, J. -E.; Johansson, L. -G.

    2015-03-18

    In this paper, the corrosion behaviour of a FeCrAl alloy was investigated at 600 °C in O2 + H2O with solid KCl applied. A kinetics and microstructural investigation showed that KCl accelerates corrosion and that potassium chromate formation depletes the protective scale in Cr, thus triggering the formation of a fast-growing iron-rich scale. Iron oxide was found to grow both inward and outward, on either side of the initial oxide. A chromia layer is formed with time underneath the iron oxide. Finally, it was found that although the alloy does not form a continuous pure alumina scale at the investigatedmore » temperature, aluminium is, however, always enriched at the oxide/alloy interface.« less

  3. A Microstructural and Kinetic Investigation of the KCl-Induced Corrosion of an FeCrAl Alloy at 600 °C

    SciTech Connect

    Israelsson, Niklas; Unocic, Kinga A.; Hellström, K.; Jonsson, T.; Norell, M.; Svensson, J. -E.; Johansson, L. -G.

    2015-03-18

    In this paper, the corrosion behaviour of a FeCrAl alloy was investigated at 600 °C in O2 + H2O with solid KCl applied. A kinetics and microstructural investigation showed that KCl accelerates corrosion and that potassium chromate formation depletes the protective scale in Cr, thus triggering the formation of a fast-growing iron-rich scale. Iron oxide was found to grow both inward and outward, on either side of the initial oxide. A chromia layer is formed with time underneath the iron oxide. Finally, it was found that although the alloy does not form a continuous pure alumina scale at the investigated temperature, aluminium is, however, always enriched at the oxide/alloy interface.

  4. The chemical stability of L-isoleucine, L-threonine, and L-serine in aqueous solutions of KCl at 298.15 K

    NASA Astrophysics Data System (ADS)

    Roy, Sanjay; Dolui, Bijoy Krishna

    2016-06-01

    The experimental saturated solubilities of L-isoleucine, L-threonine, and L-serine in aqueous mixtures of a KCl solution at 298.15 K are presented in this article. The solubilities are measured by gravimetric method. In the present study the theoretical calculation of the standard transfer Gibbs free energy, cavity forming enthalpy of transfer, cavity forming transfer Gibbs free energy, dipole-dipole interaction effect have been computed. The chemical effects of the transfer Gibbs energies for the present amino acids have been obtained by subtracting the cavity effects and dipole-dipole interaction effects from the Δ G t 0 ( i). The stability of the experimental amino acids in aqueous KCl in terms of thermodynamic parameters is explained.

  5. Investigation of concentration-dependence of thermodynamic properties of lanthanum, yttrium, scandium and terbium in eutectic LiCl-KCl molten salt

    NASA Astrophysics Data System (ADS)

    Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo

    2016-09-01

    Thermodynamic properties of rare earth metals in LiCl-KCl molten salt electrolyte are crucial to the development of electrochemical separation for the treatment of used nuclear fuels. In the present study, activity coefficient, apparent potential, and diffusion coefficient of lanthanum, yttrium, scandium, and terbium in the molten salt (58 at% LiCl and 42 at% KCl) were calculated by the method of molecular dynamics simulation up to a concentration around 3 at% at temperatures of 723 K and 773 K. It was found that the activity coefficient and the apparent potential increase with the species concentration while diffusion coefficient shows a trend of increase followed by decrease. The calculated results were validated by available measurement data of dilution cases. This research extends the range of data to a wide component and would provide further insight to the pyroprocessing design and safeguards.

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

    SciTech Connect

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

    2007-07-01

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

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

    SciTech Connect

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

    1981-03-01

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

  8. Thermodynamics of DL-α-aminobutyric acid induced solvation mechanism in aqueous KCl solutions at 288.15-308.15 K

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    The solubilities of DL-α-aminobutyric acid in KCl solutions of different concentrations are measured at 288.15-308.15 K. Gibbs energies and entropies have been determined for transfer of α-aminobutyric acid form water to aqueous KCl solution at 298.15 K. The cavity, dipole-dipole and other interactions affecting the solubility, as well as stability of the amino acid in solution are also evaluated. Gibbs energy and entropy of transfer due to interactions are computed to create the model of the complex solute-solvent and solventsolvent interactions. Molar volume, densities, dipole moment of solvent and diameter of co-solvent in aqueous potassium chloride are also evaluated.

  9. 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. PMID:27345808

  10. 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.

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

    PubMed

    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. PMID:27345808

  12. Physico-chemical investigations on the electronic partial conductivity of molten electrolytes, especially of the eutectic mixture LiCl-KCl

    NASA Astrophysics Data System (ADS)

    Rickert, H.; Meyer, M.

    1984-09-01

    The self-discharge of lithium-sulfur batteries caused by the electronic partial conductivity of the electrolyte was estimated. Stationary polarization measurements were used to determine the electronic conductivity in the eutectic melt LiCl-KCl at temperatures from 400 to 500 C. From investigations on the solubility of lithium in the melt, the diffusion coefficient of the conducting particles was obtained using a coulometric titration method.

  13. 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.

    2016-06-01

    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.

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

    PubMed

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

    2015-11-01

    Criteria for establishing water quality standards that are protective for 95% of the native species are generally based upon laboratory toxicity tests. These tests utilize common model organisms that have established test methods. However, for invertebrates these species represent mostly the zooplankton community and are not inclusive of all taxa. In order to examine a potential under-representation in emerging aquatic invertebrates the US Environmental Protection Agency has cultured a parthenogenetic mayfly, Centroptilum triangulifer (Ephemeroptera: Baetidae). This study established a 48h acute and a 14-day short-term chronic testing procedure for C. triangulifer and compared its sensitivity to two model invertebrates, Ceriodaphnia dubia and Daphnia magna. Toxicity tests were conducted to determine mortality and growth effects using standard reference toxicants: NaCl, KCl and CuSO4. In 48-h acute tests, the average LC50 for the mayfly was 659mgL(-1) NaCl, 1957mgL(-1) KCl, and 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.

  15. 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.

  16. 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

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

    PubMed

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

    2008-12-30

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

  18. 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.

  19. 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.

  20. 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.

  1. Automated potentiometric titrations in KCl/water-saturated octanol: method for quantifying factors influencing ion-pair partitioning.

    PubMed

    Scherrer, Robert A; Donovan, Stephen F

    2009-04-01

    The knowledge base of factors influencing ion pair partitioning is very sparse, primarily because of the difficulty in determining accurate log P(I) 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 P(I) 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 P(N - I))). Simple model compounds can be used. The titration procedure is described in detail, along with a program for calculating pK(a)'' 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 P(I) and log D. In contrast to the common assumption that diff (log P(N - 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 P(I) 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 P(I). 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 D(N) and log D(I). This work also brings attention to the fascinating world of nature's highly stabilized ion pairs.

  2. 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.

  3. Activity-dependent regulation of the K/Cl transporter KCC2 membrane diffusion, clustering, and function in hippocampal neurons.

    PubMed

    Chamma, Ingrid; Heubl, Martin; Chevy, Quentin; Renner, Marianne; Moutkine, Imane; Eugène, Emmanuel; Poncer, Jean Christophe; Lévi, Sabine

    2013-09-25

    The neuronal K/Cl transporter KCC2 exports chloride ions and thereby influences the efficacy and polarity of GABA signaling in the brain. KCC2 is also critical for dendritic spine morphogenesis and the maintenance of glutamatergic transmission in cortical neurons. Because KCC2 plays a pivotal role in the function of central synapses, it is of particular importance to understand the cellular and molecular mechanisms underlying its regulation. Here, we studied the impact of membrane diffusion and clustering on KCC2 function. KCC2 forms clusters in the vicinity of both excitatory and inhibitory synapses. Using quantum-dot-based single-particle tracking on rat primary hippocampal neurons, we show that KCC2 is slowed down and confined at excitatory and inhibitory synapses compared with extrasynaptic regions. However, KCC2 escapes inhibitory synapses faster than excitatory synapses, reflecting stronger molecular constraints at the latter. Interfering with KCC2-actin interactions or inhibiting F-actin polymerization releases diffusion constraints on KCC2 at excitatory but not inhibitory synapses. Thus, F-actin constrains KCC2 diffusion at excitatory synapses, whereas KCC2 is confined at inhibitory synapses by a distinct mechanism. Finally, increased neuronal activity rapidly increases the diffusion coefficient and decreases the dwell time of KCC2 at excitatory synapses. This effect involves NMDAR activation, Ca(2+) influx, KCC2 S940 dephosphorylation and calpain protease cleavage of KCC2 and is accompanied by reduced KCC2 clustering and ion transport function. Thus, activity-dependent regulation of KCC2 lateral diffusion and clustering allows for a rapid regulation of chloride homeostasis in neurons.

  4. 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

  5. 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

  6. 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.

  7. Comparison of operator-specific and nonspecific DNA binding of the lambda cI repressor: [KCl] and pH effects.

    PubMed

    Senear, D F; Batey, R

    1991-07-01

    The effects of proton and KCl activity on the nonspecific lambda cI repressor-DNA interactions and on the site-specific repressor-O(R) interactions were compared, in order to assess their roles in site specificity. The repressor-O(R) interactions were studied by using DNase I footprint titration. The Gibbs free energy changes for binding and for cooperativity were determined between 25 and 300 mM KCl, from individual-site isotherms for the binding of repressor to O(R) and to reduced-valency mutants. The proton-linked effects on repressor-O(R) interactions have been published [Senear, D. F., & Ackers, G. K. (1990) Biochemistry 29, 6568-6577; Senear, D. F., & Bolen, D. W. (1991) Methods Enzymol. (in press)]. Nonspecific binding was studied by using a nitrocellulose filter binding assay, which proved advantageous in this case, due to the relatively weak nonspecific binding, and precipitation of repressor-DNA complexes. Filter binding provided measurements at low binding density where precipitation did not occur. The data provide estimates of the Gibbs free energy changes for nonspecific, intrinsic binding, but not for cooperativity. The KCl concentration dependencies of the intrinsic binding constants indicate that ion release plays similar roles in distinguishing between the operators and in discriminating operator from nonoperator DNA. Binding to DNA is accompanied by net proton absorption. Near neutral pH, proton linkages to operator and nonoperator binding are the same. Differences at acid and at basic pH implicate the same ionizable repressor groups in distinguishing between the operators and in discriminating operator from nonoperator DNA. The results indicate similar overall modes of operator and nonoperator binding of repressor, but implicate indirect effects of DNA sequence as important contributors to sequence recognition.

  8. Volumetric, rheological, and optical properties of hydroxylamine hydrochloride aqueous solutions containing NaCl, KCl, and NH4Cl at 30°C

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Puyad, A. L.; Shaikh, U. B.; Solanke, S. S.

    2014-04-01

    Densities, viscosities, and refractive indices of aqueous solutions of hydroxylamine hydrochloride containing 0.05, 0.10, and 0.15 mol/dm3 NaCl, KCl, and NH4Cl were measured at different concentrations of hydroxylamine hydrochloride at 30°C. Viscosity coefficients A and B representing ion-ion and ion-solvent interactions were determined from Jones-Dole equation. Experimental properties and viscosity coefficients have been interpreted in terms of ion-ion and ion-solvent interactions. Ion-solvent interactions were found to be dominating over the ion-ion interactions in studied systems.

  9. Preparation of calcium hydroxyapatite nanoparticles using microreactor and their characteristics of protein adsorption.

    PubMed

    Kandori, Kazuhiko; Kuroda, Tomohiko; Togashi, Shigenori; Katayama, Erika

    2011-02-01

    The calcium hydroxyapatite Ca(10)(PO(4))(6)(OH)(2) (Hap) nanoparticles were prepared by using microreactor and employed these Hap nanoparticles to clarify the adsorption behavior of proteins. The size of Hap particles produced by the microreactor reduced in the order of a hardness of the reaction conditions for mixing Ca(OH)(2) and H(3)PO(4) aqueous solutions, such as flow rates of both solutions and temperature. Finally, the size of the smallest Hap nanoparticle became 2 × 15 nm(2), similar to that of BSA molecule (4 × 14 nm(2)). It is noteworthy that the smallest Hap nanoparticles still possesses rodlike shape, suggesting that particles are grown along c-axis even though the reactants mixed very rapidly in narrow channels of the microreactors. The X-ray diffraction patterns of the Hap nanoparticles revealed that the crystallinity of the materials produced by the microreactor is low. The FTIR measurement indicated that the Hap nanoparticles produced by microreactor were carbonate-substituted type B Hap, where the carbonate ions replace the phosphate ions in the crystal lattice. All the adsorption isotherms of acidic bovine serum albumin (BSA), neutral myoglobin (MGB), and basic lysozyme (LSZ) onto Hap nanoparticles from 1 × 10(-4) mol/dm(3) KCl solution were the Langmuirian type. The saturated amounts of adsorbed BSA (n(S)(BSA)) for the Hap nanoparticles produced by microreactor were decreased with decrease in the mean particle length, and finally it reduced to zero for the smallest Hap nanoparticles. Similar results were observed for the adsorption of LSZ; the saturated amounts of adsorbed LSZ (n(S)(LSZ)) also reduced to zero for the smallest Hap nanoparticles. However, in the case of MGB, the saturated mounts of adsorbed MGB (n(S)(MGB)) are also depressed with decreased in their particle size, but about half of MGB molecules still adsorbed onto the smallest Hap nanoparticles. This difference in the protein adsorption behavior was explained by the difference

  10. 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.

  11. 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.

  12. 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.

  13. High temperature (35)Cl nuclear magnetic resonance study of the LiCl-KCl system and the effect of CeCl3 dissolution.

    PubMed

    Zhang, H; Farnan, I

    2016-08-15

    This paper examines the dynamics of the LiCl-KCl system over a range of temperatures in order to understand the local structure surrounding chlorine, which is the common ion in these systems, during molten salt pyro-processing. Chlorine-35 nuclear magnetic resonance (NMR) is sensitive to the local environments of the resonant nuclei and their motion on a diffusive timescale. Thus, it is a good probe of the atomic scale processes controlling the viscosities, diffusivities and conductivities of these molten salts. The average isotropic chemical shifts (((35)Cl)δ) and spin-lattice relaxation times (T1) of (35)Cl in (Li,K)Cl salt mixtures have been obtained over a compositional range of 0-100 mol% KCl with an interval of 10 mol% using high temperature nuclear magnetic resonance (NMR) spectroscopy from room temperature up to 890 °C. The ((35)Cl)δ in the two end member salts are consistent with the cation-anion radius ratio as previously measured on the solid halides and the average radius ratio of cation to anion, can be used to explain the variation of ((35)Cl)δ with composition. The quadrupolar interaction is found to be responsible for the spin-lattice relaxation of the (35)Cl, and the activation energies for T1 relaxation have been obtained for all compositions. The measured T1 ((35)Cl) activation energies do not vary linearly with composition and peak at 50% KCl, which also coincides with the Chemla point for this system. They also are in good agreement with the values from equivalent conductivity measurements. To investigate the response of the system to solutes, 8 wt% of CeCl3 was added to the pure LiCl as a surrogate actinide. The shift induced was 120 ppm and the activation energy for the T1 ((35)Cl) increased by a factor of four. This is a promising preliminary result for probing the effect of actinide dissolution on the dynamics of these pyro-processing salts. PMID:27212395

  14. High temperature (35)Cl nuclear magnetic resonance study of the LiCl-KCl system and the effect of CeCl3 dissolution.

    PubMed

    Zhang, H; Farnan, I

    2016-08-15

    This paper examines the dynamics of the LiCl-KCl system over a range of temperatures in order to understand the local structure surrounding chlorine, which is the common ion in these systems, during molten salt pyro-processing. Chlorine-35 nuclear magnetic resonance (NMR) is sensitive to the local environments of the resonant nuclei and their motion on a diffusive timescale. Thus, it is a good probe of the atomic scale processes controlling the viscosities, diffusivities and conductivities of these molten salts. The average isotropic chemical shifts (((35)Cl)δ) and spin-lattice relaxation times (T1) of (35)Cl in (Li,K)Cl salt mixtures have been obtained over a compositional range of 0-100 mol% KCl with an interval of 10 mol% using high temperature nuclear magnetic resonance (NMR) spectroscopy from room temperature up to 890 °C. The ((35)Cl)δ in the two end member salts are consistent with the cation-anion radius ratio as previously measured on the solid halides and the average radius ratio of cation to anion, can be used to explain the variation of ((35)Cl)δ with composition. The quadrupolar interaction is found to be responsible for the spin-lattice relaxation of the (35)Cl, and the activation energies for T1 relaxation have been obtained for all compositions. The measured T1 ((35)Cl) activation energies do not vary linearly with composition and peak at 50% KCl, which also coincides with the Chemla point for this system. They also are in good agreement with the values from equivalent conductivity measurements. To investigate the response of the system to solutes, 8 wt% of CeCl3 was added to the pure LiCl as a surrogate actinide. The shift induced was 120 ppm and the activation energy for the T1 ((35)Cl) increased by a factor of four. This is a promising preliminary result for probing the effect of actinide dissolution on the dynamics of these pyro-processing salts.

  15. Magnetic anisotropy induced by crystal distortion in Ge{sub 1−x}Mn{sub x}Te/PbTe//KCl (001) ferromagnetic semiconductor layers

    SciTech Connect

    Knoff, W. Łusakowski, A.; Domagała, J. Z.; Minikayev, R.; Taliashvili, B.; Łusakowska, E.; Pieniążek, A.; Szczerbakow, A.; Story, T.

    2015-09-21

    Ferromagnetic resonance (FMR) study of magnetic anisotropy is presented for thin layers of IV-VI diluted magnetic semiconductor Ge{sub 1−x}Mn{sub x}Te with x = 0.14 grown by molecular beam epitaxy on KCl (001) substrate with a thin PbTe buffer. Analysis of the angular dependence of the FMR resonant field reveals that an easy magnetization axis is located near to the normal to the layer plane and is controlled by two crystal distortions present in these rhombohedral Ge{sub 1−x}Mn{sub x}Te layers: the ferroelectric distortion with the relative shift of cation and anion sub-lattices along the [111] crystal direction and the biaxial in-plane, compressive strain due to thermal mismatch.

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

    SciTech Connect

    Lantelme, F.; Berghoute, Y.

    1999-11-01

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

  17. 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.

  18. 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.

  19. 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.

  20. WNK protein kinases modulate cellular Cl- flux by altering the phosphorylation state of the Na-K-Cl and K-Cl cotransporters.

    PubMed

    Kahle, Kristopher T; Rinehart, Jesse; Ring, Aaron; Gimenez, Ignacio; Gamba, Gerardo; Hebert, Steven C; Lifton, Richard P

    2006-10-01

    Precise control of cellular Cl(-) transport is necessary for many fundamental physiological processes. For example, the intracellular concentration of Cl(-), fine-tuned through the coordinated action of cellular Cl(-) influx and efflux mechanisms, determines whether a neuron's response to GABA is excitatory or inhibitory. In epithelia, synchrony between apical and basolateral Cl(-) flux, and transcellular and paracellular Cl(-) transport, is necessary for efficient transepithelial Cl(-) reabsorption or secretion. In cells throughout the body, coordination of Cl(-) entry and exit mechanisms help defend against changes in cell volume. The Na-K-Cl and K-Cl cotransporters of the SLC12 gene family are important molecular determinants of Cl(-) entry and exit, respectively, in these systems. The WNK serine-threonine kinase family, members of which are mutated in an inherited form of human hypertension, are components of a signaling pathway that coordinates Cl(-) influx and efflux through SLC12 cotransporters to dynamically regulate intracellular Cl(-) activity. PMID:16990453

  1. 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.

  2. Chlorination of UO 2, PuO 2 and rare earth oxides using ZrCl 4 in LiCl-KCl eutectic melt

    NASA Astrophysics Data System (ADS)

    Sakamura, Yoshiharu; Inoue, Tadashi; Iwai, Takashi; Moriyama, Hirotake

    2005-04-01

    A new chlorination method using ZrCl 4 in a molten salt bath has been investigated for the pyrometallurgical reprocessing of nuclear fuels. ZrCl 4 has a high reactivity with oxygen but is not corrosive to refractory metals such as steel. Rare earth oxides (La 2O 3, CeO 2, Nd 2O 3 and Y 2O 3) and actinide oxides (UO 2 and PuO 2) were allowed to react with ZrCl 4 in a LiCl-KCl eutectic salt at 773 K to give a metal chloride solution and a precipitate of ZrO 2. An addition of zirconium metal as a reductant was effective in chlorinating the dioxides. When the oxides were in powder form, the reaction was observed to progress rapidly. Cyclic voltammetry provided a convenient way of establishing when the reaction was completed. It was demonstrated that the ZrCl 4 chlorination method, free from corrosive gas, was very simple and useful.

  3. 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.

  4. The flavonoid chrysin, an endocrine disrupter, relaxes cholecystokinin- and KCl-induced tension in male guinea pig gallbladder strips through multiple signaling pathways.

    PubMed

    Kline, Loren W; Karpinski, Edward

    2014-01-01

    The bioflavonoids have effects on vascular smooth muscle and gastrointestinal smooth muscle. The flavone and phytoestrogen, chrysin, has been shown to have a vasorelaxant effect on resistance blood vessels. This effect was mediated by nitric oxide (NO). Chrysin inhibited aromatase/estrogen biosynthesis in postmenopausal women. The purpose of this study was to determine if chrysin had an effect on cholecystokinin- or KCl-induced tension in male guinea pig gallbladder strips. In addition, the second messenger(s) system(s) that mediated the effect were to be determined. A pharmacologic approach was used. Male guinea pig gallbladder strips were placed in in vitro chambers filled with Krebs solution, maintained at 37 °C, and gassed with 95% O2-5% CO2. Changes in tension were recorded using a polygraph. It was shown that the PKA/cAMP second messenger system mediated part of the observed chrysin-induced relaxation of cholecystokinin-induced tension, the PKC system also mediated part of the relaxation, and the inhibition of both extracellular Ca(2+) entry and intracellular Ca(2+) release also mediated the chrysin-induced relaxation. This is the first report of chrysin having an effect on gallbladder smooth muscle contraction. PMID:24291637

  5. 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; Dupré, Nicolas; Lu, Jianming; Fan, Xuemo; Song, Luyan; Rivière, Jean-Baptiste; Prévost, Claude; Horst, Jürgen; 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.

  6. Electrochemistry and the mechanisms of nucleation and growth of neodymium during electroreduction from LiCl-KCl eutectic salts on Mo substrate

    NASA Astrophysics Data System (ADS)

    Tang, Hao; Pesic, Batric

    2015-03-01

    The electrochemical behavior of NdCl3 was studied on a Mo electrode in molten LiCl-KCl eutectic salts. The electroreduction of Nd(III)/Nd(0) involved two reaction steps, as confirmed by three different electrochemical techniques. In the first reaction step, Nd(III) is converted into soluble Nd(II), which undergoes further reduction into metallic Nd(0) in the second reaction step. The standard reaction rate constants for each reaction step were determined by Nicholson method. The rate constant values were used in Matsuda-Ayabe's criteria for testing the electrochemical reversibility. Accordingly, both reaction steps were quasi-reversible redox reactions. The nucleation mechanisms of neodymium metal deposited on a Mo substrate were predicted by using Scharifker-Hill model, and tested for the first time by scanning electron microscopy (SEM) studies of the electrode surface. The SEM studies confirmed that for the low initial concentration of NdCl3, neodymium nucleates and grows progressively, while for higher NdCl3 concentrations, the related mechanism is instantaneous. Both are governed by the aggregative growth mechanisms based on surface mobility of formed nanoclusters.

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  8. 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.

  9. Physical chemistry of molten-salt batteries. Final report, October 1, 1981-September 30, 1982. LiCl precipitation from LiCl-KCl anolyte in porous Li-Al electrodes

    SciTech Connect

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

    1983-05-01

    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. LiCl precipitation 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.

  10. [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

  11. 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

    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.

  12. Investigating microstructural evolution during the electroreduction of UO2 to U in LiCl-KCl eutectic using focused ion beam tomography

    NASA Astrophysics Data System (ADS)

    Brown, L. D.; Abdulaziz, R.; Tjaden, B.; Inman, D.; Brett, D. J. L.; Shearing, P. R.

    2016-11-01

    Reprocessing of spent nuclear fuels using molten salt media is an attractive alternative to liquid-liquid extraction techniques. Pyroelectrochemical processing utilizes direct, selective, electrochemical reduction of uranium dioxide, followed by selective electroplating of a uranium metal. Thermodynamic prediction of the electrochemical reduction of UO2 to U in LiCl-KCl eutectic has shown to be a function of the oxide ion activity. The pO2- of the salt may be affected by the microstructure of the UO2 electrode. A uranium dioxide filled "micro-bucket" electrode has been partially electroreduced to uranium metal in molten lithium chloride-potassium chloride eutectic. This partial electroreduction resulted in two distinct microstructures: a dense UO2 and a porous U metal structure were characterised by energy dispersive X-ray spectroscopy. Focused ion beam tomography was performed on five regions of this electrode which revealed an overall porosity ranging from 17.36% at the outer edge to 3.91% towards the centre, commensurate with the expected extent of reaction in each location. The pore connectivity was also seen to reduce from 88.32% to 17.86% in the same regions and the tortuosity through the sample was modelled along the axis of propagation of the electroreduction, which was seen to increase from a value of 4.42 to a value of infinity (disconnected pores). These microstructural characteristics could impede the transport of O2- ions resulting in a change in the local pO2- which could result in the inability to perform the electroreduction.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Ethanol, feed components and fungal biomass production from field bean (Vicia faba var. equina) seeds in an integrated process.

    PubMed

    Pietrzak, Witold; Kawa-Rygielska, Joanna; Król, Barbara; Lennartsson, Patrik R; Taherzadeh, Mohammad J

    2016-09-01

    The use of field beans, a non-food leguminous crop, was studied for ethanol, feed components and fungal biomass production. The seeds were hydrolyzed using enzymes or with combination of acid (H3PO4) and alkaline (Ca(OH)2) pretreatment and enzymatic hydrolysis. Fermentation by Saccharomyces cerevisiae, with or without removal of suspended solids, yielded 38.3-42.5gL(-1) ethanol (71.3-79.2% efficiency). The filtration residues contained ca. 247-326gkg(-1) crude protein, 10.6-15.5% acid detergent fiber and 19.9-29.1% neutral detergent fiber. They were enriched in phenolics (by up to 93.4%) and depleted in condensed tannin (by up to 59.3%) in comparison to the raw material. The thin stillages were used for cultivation of edible fungus Neurospora intermedia which produced 8.5-15.9gL(-1) ethanol and 4.8-16.2gL(-1) biomass containing over 62% protein. The mass balances showed that fermentation of unfiltered mashes was more efficient yielding up to 195.9gkg(-1) ethanol and 84.4% of protein recovery. PMID:27233099

  18. 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.

  19. 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.

  20. 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

  1. RAPID COMMUNICATION: Electrical transport properties of bulk MgB2 materials synthesized by electrolysis on fused mixtures of MgCl2, NaCl, KCl and MgB2O4

    NASA Astrophysics Data System (ADS)

    Yoshii, Kenji; Abe, Hideki

    2002-10-01

    Bulk MgB2 materials have been synthesized electrochemically from fused mixtures of MgCl2, NaCl, KCl and MgB2O4 under an Ar flow at 600 °C. Electrical resistivity measurements for the samples show an onset of superconducting transition at ~37 K in the absence of an applied magnetic field. This temperature is quite close to that observed from magnetic measurements. The resistivity decreases to zero below ~32 K. From the applied-field dependence of resistivity, the upper critical field and the coherence length were calculated to be 9.7 T and 5.9 nm at 0 K, respectively.

  2. 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).

  3. Aluminum fluxing salts: a critical review of the chemistry and structures of alkali aluminum halides. Information circular/1986. [System NaCl-KCl-AlCl/sub 3/-NaF-KF-AlF/sub 3/

    SciTech Connect

    Sorrell, C.A.; Groetsch, J.G.; Soboroff, D.M.

    1986-01-01

    The publication reviews the structural characteristics of crystalline phases and phase equilibria data for the system NaCl-KCl-AlCl/sub 3/-NaF-KF-AlF/sub 3/, which encompasses a large number of molten salt fluxes currently used in aluminum recycling. Its purpose is to provide guidelines for research into the relationships between molten salt compositions and their physical properties, notably vapor pressures, densities, surface tensions, and viscosities, knowledge of which is essential to minimizing fluxing efficiencies and metal recovery and minimizing hazardous emissions and disposal problems. In addition, the report describes experimental determinations of sub-solidus compatibility relationships in the system, which is of the quaternary reciprocal type, containing 12 different stable 4-phase assemblages in the solid state. The compatibility diagram serves to define the important compositional planes across which important changes in properties are likely to occur.

  4. Influence of partial replacement of NaCl with KCl, CaCl2 and MgCl2 on lipolysis and lipid oxidation in dry-cured ham.

    PubMed

    Ripollés, Susana; Campagnol, Paulo Cezar Bastianello; Armenteros, Mónica; Aristoy, M Concepción; Toldrá, Fidel

    2011-09-01

    Sodium intake above nutritional recommendations may involve harmful consequences to health such as the increased risk of cardiovascular diseases. Dry-cured ham constitutes a product with a relatively large amount of sodium. Thus, to obtain a healthier product for consumers with reduced sodium content, two formulations containing KCl alone (formulation II) or mixed with CaCl2 and MgCl2 (formulation III) have been proposed to partially replace NaCl. Lipolysis and lipid oxidation occurring in hams processed with these formulations have been studied since they have direct influence on the final flavor. No significant differences in acid lipase activity or lipid oxidation were found at the end of the process between the alternative formulations and formulation I (control with 100% NaCl). Differences in some free fatty acids, generated along the processing, were detected among treatments and at the end of dry-curing. Data suggests a slight trend towards a major lipolysis during treatment III.

  5. 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.

  6. Calculation of NaCl, KCl and LiCl Salts Activity Coefficients in Polyethylene Glycol (PEG4000)-Water System Using Modified PHSC Equation of State, Extended Debye-Hückel Model and Pitzer Model

    NASA Astrophysics Data System (ADS)

    Marjani, Azam

    2016-07-01

    For biomolecules and cell particles purification and separation in biological engineering, besides the chromatography as mostly applied process, aqueous two-phase systems (ATPS) are of the most favorable separation processes that are worth to be investigated in thermodynamic theoretically. In recent years, thermodynamic calculation of ATPS properties has attracted much attention due to their great applications in chemical industries such as separation processes. These phase calculations of ATPS have inherent complexity due to the presence of ions and polymers in aqueous solution. In this work, for target ternary systems of polyethylene glycol (PEG4000)-salt-water, thermodynamic investigation for constituent systems with three salts (NaCl, KCl and LiCl) has been carried out as PEG is the most favorable polymer in ATPS. The modified perturbed hard sphere chain (PHSC) equation of state (EOS), extended Debye-Hückel and Pitzer models were employed for calculation of activity coefficients for the considered systems. Four additional statistical parameters were considered to ensure the consistency of correlations and introduced as objective functions in the particle swarm optimization algorithm. The results showed desirable agreement to the available experimental data, and the order of recommendation of studied models is PHSC EOS > extended Debye-Hückel > Pitzer. The concluding remark is that the all the employed models are reliable in such calculations and can be used for thermodynamic correlation/predictions; however, by using an ion-based parameter calculation method, the PHSC EOS reveals both reliability and universality of applications.

  7. Estimation of key physical properties for LaCl3 in molten eutectic LiCl-KCl by fitting cyclic voltammetry data to a BET-based electrode reaction kinetics model

    NASA Astrophysics Data System (ADS)

    Samin, Adib; Wang, Zhonghang; Lahti, Erik; Simpson, Michael; Zhang, Jinsuo

    2016-07-01

    Understanding the electrochemical properties of rare earth elements is important for developing efficient techniques for separating rare earth elements from actinides recovered during the electrodeposition process. In this study the cyclic voltammetry for lanthanum in molten LiClKCl eutectic was recorded at 773 K for different scan rates and different bulk concentrations. A model accounting for mass transport, kinetics and adsorption was applied to analyze the experimental data via performing a nonlinear least squares fit. The results of the simulation are compared against the results of a conventional analysis of the cyclic voltammograms and against the existing literature. At the scan rates used, the reduction/oxidation process is quasi-reversible. The values of diffusivities derived from simulation were larger than the ones derived commonly using equations for diffusion-limited processes. However, those equations were derived based on an assumption of reversibility. This simulation-based approach may provide a more accurate option for analyzing systems that do not exhibit reversibility.

  8. Development of advanced batteries at Argonne National Laboratory. Summary report for 1979. [Li-Al/LiCl-KCl/FeS or FeS/sub 2/, 40 kWh; also Ca-Si/FeS/sub 2/

    SciTech Connect

    1980-04-01

    A summary for 1979 of Argonne National Laboratory's program on the development of advanced batteries is presented. These batteries are being developed for electric-vehicle propulsion and stationary energy-storage applications. The principal cells under investigation at present are of a vertically oriented, prismatic design with one or more inner positive electrodes of FeS or FeS/sub 2/, facing negative electrodes of Li-Al alloy, and molten LiCl-KCl electrolyte; the cell operating temperature is 400 to 500/sup 0/C. A small effort on the development of a calcium/metal sulfide cell is also being conducted. During 1979, cell and battery development work continued at ANL and contractors' laboratories. A 40-kWh electric-vehicle battery (designated Mark IA) was fabricated and delivered by Eagle-Picher Industries, Inc. to ANL for testing. During heat-up, one of the modules failed due to a short circuit. A failure analysis was conducted, and the Mark IA program, completed. Development work on the next electric-vehicle battery (Mark II) was initiated at Eagle-Picher and Gould, Inc. Work on stationary energy-storage batteries consisted primarily of conceptual design studies. 9 figures, 7 tables.

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

    NASA Astrophysics Data System (ADS)

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

    2004-03-01

    The molar conductivities Λ of NaCl, KCl, and CsCl in liquid methanol were measured in the concentration range of (0.3-2.0)×10-3 mol dm-3 and the temperature range of 60-240 °C along the liquid-vapor coexistence curve. The temperature range corresponds to the solvent density range of (2.78-1.55)ρc, where ρc=0.2756 g cm-3 is the critical density of methanol. The concentration dependence of Λ at each temperature and density (pressure) has been analyzed by the Fuoss-Chen-Justice equation to obtain the limiting molar conductivity Λ0 and the molar association constant KA. For all the electrolytes studied, Λ0 increased almost linearly with decreasing density at densities above 2.0ρc, while the opposite tendency was observed at lower densities. The relative contribution of the nonhydrodynamic effect on the translational friction coefficient ζ was estimated in terms of Δζ/ζ, where the residual friction coefficient Δζ is the difference between ζ and the Stokes friction coefficient ζS. At densities above 2.0ρc, Δζ/ζ increased with decreasing density though ζ and Δζ decrease, and the tendencies are common for all the ions studied. The density dependences of ζ and Δζ/ζ were explained well by the Hubbard-Onsager (HO) dielectric friction theory based on the sphere-in-continuum model. At densities below 2.0ρc, however, the experimental results cannot be explained by the HO theory.

  10. Ions and counterions in a biological channel: a molecular dynamics simulation of OmpF porin from Escherichia coli in an explicit membrane with 1 M KCl aqueous salt solution.

    PubMed

    Im, Wonpil; Roux, Benoît

    2002-06-21

    A 5 ns all-atom molecular dynamics trajectory of Escherichia coli OmpF porin embedded in an explicit dimyristoyl-phosphatidylcholine (DMPC) bilayer bathed by a 1 M [KCl] aqueous salt solution is generated to explore the microscopic details of the mechanism of ion permeation. The atomic model includes the OmpF trimer, 124 DMPC, 13470 water molecules as well as 231 K+ and 201 Cl-, for a total of 70,693 atoms. The structural and dynamical results are in excellent agreement with the X-ray data. The global root-mean-square deviation of the backbone atoms relative to the X-ray structure is 1.4 A. A cluster of three fully charged arginine (Arg42, Arg82, and Arg132) facing two acidic residues (Asp113 and Glu117) on L3 in the narrowest part of the aqueous pore is observed to be very stable in the crystallographic conformation. In this region of the pore, the water molecules are markedly oriented perpendicular to the channel axis due to the strong transversal electrostatic field arising from those residues. On average the size of the pore is smaller during the simulation than in the X-ray structure, undergoing small fluctuations. No large movements of loop L3 leading to a gating of the pore are observed. Remarkably, it is observed that K+ and Cl- follow two well-separated average pathways spanning over nearly 40 A along the axis of the pore. In the center of the monomer, the two screw-like pathways have a left-handed twist, undergoing a counter-clockwise rotation of 180 degrees from the extracellular vestibule to the pore periplasmic side. In the pore, the dynamical diffusion constants of the ions are reduced by about 50% relative to their value in bulk solvent. Analysis of ion solvation across the channel reveals that the contributions from the water and the protein are complementary, keeping the total solvation number of both ions nearly constant. Unsurprisingly, K+ have a higher propensity to occupy the aqueous pore than Cl-, consistent with the cation selectivity of the

  11. 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

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

    PubMed

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

    2016-01-01

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

  13. Field assessment of treatment efficacy by three methods of phosphoric acid application in lead-contaminated urban soil.

    PubMed

    Yang, John; Mosby, David

    2006-07-31

    In situ soil treatment using phosphoric acid (H(3)PO(4)) may be an effective remedial technology for immobilizing soil Pb and reducing Pb risk to human health and ecosystem. The treatment efficacy of three H(3)PO(4) application methods was assessed in a smelter-contaminated urban soil located in the Jasper County Superfund Site, Missouri. Soil, with an average of 3529 mg Pb kg(-1) and in the 2- by 4-m plot size, was treated with H(3)PO(4) at a rate of 10 g P kg(-1) in four replicates by each of three methods: rototilling; surface application; pressure injection. Three soil cores, 2.5-cm diameter and 30-cm long, were taken from each plot before and 90 days after treatment and analyzed for soluble P, bioaccessible Pb and solid-Pb speciation. Applications of H(3)PO(4) induced the heterogeneity of soluble P in soil, with the highest concentrations in the surface. Three application methods mixed the H(3)PO(4) more effectively in the horizontals than the verticals of treated soil zone. The H(3)PO(4) applications significantly reduced Pb bioaccessibility in the soil, which was influenced by the concentrations of soil soluble P and solid-Pb species. The risk reductions of soil Pb were achieved by formation of pyromorphites or pyromorphite-like minerals. The rototilling appears to be the most effective treatment method in context of the homogeneity of soluble P and the reduction of Pb bioaccessibility in treated soil.

  14. 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

  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. 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

  17. Ab Initio Study of KCl and NaCl Clusters

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  18. Quantum Theoretical Study of KCl and LiCl Clusters

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  19. Proton conducting behavior of a novel polymeric gel membrane based on poly(ethylene oxide)-grafted-poly(methacrylate)

    NASA Astrophysics Data System (ADS)

    Qiao, Jinli; Yoshimoto, Nobuko; Morita, Masayuki

    A novel proton conducting polymeric gel membrane that consists of poly(ethylene oxide)-grafted-poly(methacrylate) (PEO-PMA) with poly(ethylene glycol) dimethyl ether (PEGDE) as a plasticizer doped with aqueous phosphoric acid (H 3PO 4) has been prepared and its physicochemical properties were studied in detail. The ionic conductivity was dependent much on the concentration of H 3PO 4, the immersion time, and content of the plasticizer. This type of proton conducting polymeric gels shares not only good mechanical properties but also thermal stability. Maximum conductivities up to 2.6×10 -2 S cm -1 at room temperature (25 °C) and 2.8×10 -2 S cm -1 at 70 °C were obtained for the composition of the polymer matrix to the plasticizer as 35/65 (in mass) after the H 3PO 4 doping from the aqueous solution with 2.93 mol l -1. FT-IR spectra showed that these high proton conductivities are attributed to the presence of excesses free H 3PO 4 in the polymeric gel in addition to the hydrogen-bonded H 3PO 4 to the polymer matrix.

  20. 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.%.

  1. 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.

  2. 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.

  3. Phase diagram involving the mesomorphic behavior of binary mixture of sodium oleate and orthophosphoric acid

    NASA Astrophysics Data System (ADS)

    Govindaiah, T. N.; Sreepad, H. R.

    2015-04-01

    The present investigation deals with the binary mixture of two non-mesogenic compounds, viz. sodium oleate (Naol) and orthophosphoric acid (H3PO4) which exhibits very interesting liquid crystalline smectic phases at large range of concentrations and temperature. The mixtures with concentrations ranging from 10% to 90% Naol in H3PO4 exhibit SmA, SmC, SmE and SmB phases, sequentially when the specimen is cooled from its isotropic phase. Physical properties, such as ultrasonic velocity, adiabatic compressibility and molar compressibility, show anomalous behavior at the isotropic to mesosphase transition.

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

    PubMed

    Bodénan, F; Deniard, Ph

    2003-05-01

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

  5. 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.

  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. 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 ...

  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. Electron impact cross sections for surrogates of DNA sugar phosphate backbone

    NASA Astrophysics Data System (ADS)

    Bhowmik, Pooja; Joshipura, K. N.; Pandya, Siddharth

    2012-11-01

    Ionization and elastic cross sections by electron impact on H3PO4 and OP(OCH3)3 which are substitutes for the components of DNA phosphate group. We have employed the Complex Scattering Potential-ionization contribution (CSP-ic) formalism to calculate the cross sections in the energy range from ionization threshold to 2000 eV.

  11. Lead immobilization using phosphoric acid in a smelter-contaminated urban soil.

    PubMed

    Yang, J; Mosby, D E; Casteel, S W; Blanchar, R W

    2001-09-01

    Transformation of soil lead (Pb) to pyromorphite, a lead phosphate, may be a cost-effective remedial strategy for immobilizing soil Pb and reducing Pb bioavailability. Soil treatment using phosphoric acid (H3PO4) was assessed for its efficacy to reduce Pb solubility and bioaccessibility. Soil containing 4,360 mg of Pb kg(-1), collected from a smelter-contaminated site in Joplin, MO, was reacted with 1,250, 2,500, 5,000, and 10,000 mg of P kg(-1) as H3PO4. The reaction was followed by measurements of Pb bioaccessibility, solubility products, and microprobe analyses. Soluble Pb concentration in the soil decreased with increasing H3PO4 addition. Adding 10,000 mg of P kg(-1) reduced bioaccessible Pb by 60%. The logarithm of bioaccessible Pb decreased as a linear function of increasing H3PO4 addition with an R2 of 0.989. A higher soil/solution ratio was required to extract bioaccessible Pb after the treatment. Microprobe analyses showed that the Pb particles contained P and Cl after the reaction, and the spectra generated by the wavelength-dispersive spectrometer were similar to those of synthetic chloropyromorphite. Lead solubility in the P-treated soil was less than predicted for hydroxypyromorphite [Pbs(PO4)3-OH] and greater than predicted for chloropyromorphite [Pbs(PO4)3Cl]. The P treatment caused approximately 23% redistribution of soil Pb from the clay and silt size fractions to the sand fraction. Soil treatment with H3PO4 resulted in the formation of a compound similar to chloropyromorphite and reduced bioaccessibility of soil Pb, which may have a potential as an in situ technique for Pb-contaminated soil remediation.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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.

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

    SciTech Connect

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

    2012-10-01

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

  18. Electrochemical behavior of yttrium ion in LiCl-KCl-NaCl eutectic melt

    SciTech Connect

    Hikino, S.; Xie, G.; Ema, K.; Ito, Y. ); Shou, Z.M. )

    1992-07-01

    This paper reports that the electrochemical reduction of yttrium ion on a molybdenum electrode in a LiCl-LCl-NaCl eutectic melt at 723 K was found to be almost reversible and to proceed by a one-step three electron reaction. The diffusion coefficient D of the Y(III) ion was measured to be (3.3 {plus minus} 0.4) {times} 10{sup {minus}6} cm{sup 2}s{sup {minus}1} by cyclic voltammetry, (5.0 {plus minus} 0.9) {times} 10{sup {minus}6} cm{sup 2}s{sup {minus}1} by the rotating disk electrode method, and (7.1 {plus minus} 0.7) {times} 10{sup {minus}6} cm{sup 2}s{sup {minus}1} by chronopotentiometry. The D values obtained by the latter two methods are in fairly good agreement with each other. The rather low D value obtained by cyclic voltammetry might be attributed to the fact that yttrium metal can dissolve slightly in the chloride melt. The standard potential of Y(III)/Y(0) coupled was determined to be ({minus}3.174 {plus minus} 0.006) V (vs. Cl{sub 2}/Cl{sup {minus}}) by open-circuit potentiometry, ({minus}3.15 {plus minus} 0.02) V (vs. Cl{sub 2}Cl{sup {minus}}) by the totaling disk electrode method and ({minus}3.16) {plus minus} 0.02) V (vs. Cl{sub 2}/Cl{sup {minus}}) by chronopotentiometry. These three values are in good agreement with each other. Several types of Ni-Y intermetallic compounds were found to be formed on a nickel electrode.

  19. Functional and molecular characterization of multiple K-Cl cotransporter isoforms in corneal epithelial cells

    PubMed Central

    Capó-Aponte, José E.; Wang, Zheng; Bildin, Victor N.; Iserovich, Pavel; Pan, Zan; Zhang, Fan; Pokorny, Kathryn S.; Reinach, Peter S.

    2009-01-01

    The dependence of regulatory volume decrease (RVD) activity on potassium–chloride cotransporter (KCC) isoform expression was characterized in corneal epithelial cells (CEC). During exposure to a 50% hypotonic challenge, the RVD response was larger in SV40-immortalized human CEC (HCEC) than in SV40-immortalized rabbit CEC (RCEC). A KCC inhibitor—[(dihydroindenyl)oxy] alkanoic acid (DIOA)—blocked RVD more in HCEC than RCEC. Under isotonic conditions, N-ethylmaleimide (NEM) produced KCC activation and transient cell shrinkage. Both of these changes were greater in HCEC than in RCEC. Immunoblot analysis of HCEC, RCEC, primary human CEC (pHCEC), and primary bovine CEC (BCEC) plasma membrane enriched fractions revealed KCC1, KCC3, and KCC4 isoform expression, whereas KCC2 was undetectable. During a hypotonic challenge, KCC1 membrane content increased more rapidly in HCEC than in RCEC. Such a challenge induced a larger increase and more transient p44/42MAPK activation in HCEC than RCEC. On the other hand, HCEC and RCEC p38MAPK phosphorylation reached peak activations at 2.5 and 15 min, respectively. Only in HCEC, pharmacological manipulation of KCC activity modified the hypotonicity-induced activation of p44/42MAPK, whereas p38MAPK phosphorylation was insensitive to such procedures in both cell lines. Larger increases in HCEC KCC1 membrane protein content correlate with their ability to undergo faster and more complete RVD. Furthermore, pharmacological activation of KCC increased p44/42MAPK phosphorylation in HCEC but not in RCEC, presumably a reflection of low KCC membrane expression in RCEC. These findings suggest that KCC1 plays a role in (i) maintaining isotonic steady-state cell volume homeostasis, (ii) recovery of isotonic cell volume after a hypotonic challenge through RVD, and (iii) regulating hypotonicity-induced activation of the p44/42MAPK signaling pathway required for cell proliferation. PMID:17418819

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

    SciTech Connect

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

    1980-08-01

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

  1. Solubility of Rock in Steam Atmospheres of Planets

    NASA Astrophysics Data System (ADS)

    Fegley, Bruce, Jr.; Jacobson, Nathan S.; Williams, K. B.; Plane, J. M. C.; Schaefer, L.; Lodders, Katharina

    2016-06-01

    Extensive experimental studies show that all major rock-forming elements (e.g., Si, Mg, Fe, Ca, Al, Na, K) dissolve in steam to a greater or lesser extent. We use these results to compute chemical equilibrium abundances of rocky-element-bearing gases in steam atmospheres equilibrated with silicate magma oceans. Rocky elements partition into steam atmospheres as volatile hydroxide gases (e.g., Si(OH)4, Mg(OH)2, Fe(OH)2, Ni(OH)2, Al(OH)3, Ca(OH)2, NaOH, KOH) and via reaction with HF and HCl as volatile halide gases (e.g., NaCl, KCl, CaFOH, CaClOH, FAl(OH)2) in much larger amounts than expected from their vapor pressures over volatile-free solid or molten rock at high temperatures expected for steam atmospheres on the early Earth and hot rocky exoplanets. We quantitatively compute the extent of fractional vaporization by defining gas/magma distribution coefficients and show that Earth's subsolar Si/Mg ratio may be due to loss of a primordial steam atmosphere. We conclude that hot rocky exoplanets that are undergoing or have undergone escape of steam-bearing atmospheres may experience fractional vaporization and loss of Si, Mg, Fe, Ni, Al, Ca, Na, and K. This loss can modify their bulk composition, density, heat balance, and interior structure.

  2. The Solubility of Rock in Steam Atmospheres of the Early Earth and Hot Rocky Exoplanets

    NASA Astrophysics Data System (ADS)

    Fegley, Bruce

    2016-07-01

    Extensive experimental studies show all major rock-forming elements (e.g., Si, Mg, Fe, Ca, Al, Na, K) dissolve in steam to a greater or lesser extent. We use these results to compute chemical equilibrium abundances of rocky element - bearing gases in steam atmospheres equilibrated with silicate magma oceans. Rocky elements partition into steam atmospheres as volatile hydroxide gases (e.g., Si(OH)4, Mg(OH)2, Fe(OH)2, Ni(OH)2, Al(OH)3, Ca(OH)2, NaOH, KOH) and via reaction with HF and HCl as volatile halide gases (e.g., NaCl, KCl, CaFOH, CaClOH, FAl(OH)2) in much larger amounts than expected from their vapor pressures over volatile-free solid or molten rock at high temperatures expected for steam atmospheres on the early Earth and hot rocky exoplanets. We quantitatively compute the extent of fractional vaporization by defining gas/magma distribution coefficients and show Earth's sub-solar Si/Mg ratio may be due to loss of a primordial steam atmosphere. We conclude hot rocky exoplanets that are undergoing or have undergone escape of steam-bearing atmospheres may experience fractional vaporization and loss of Si, Mg, Fe, Ni, Al, Ca, Na, and K. This loss can modify their bulk composition, density, heat balance, and interior structure. This work was supported by NSF Astronomy Program Grant AST-1412175.

  3. Chemical characterization of combustion deposits by TOF-SIMS

    NASA Astrophysics Data System (ADS)

    Sjövall, P.; Lausmaa, J.; Tullin, C.; Högberg, J.

    2003-01-01

    We have investigated the potential usefulness of TOF-SIMS for chemical analysis of deposits formed in combustion reactors. By using TOF-SIMS, it was possible to (i) identify inorganic chemical compounds in the deposits, (ii) semi-quantitatively estimate the relative concentrations of the main constituents and (iii) obtain images showing the lateral distribution of the main constituents, on the surface and in cross-sections of deposit samples. It was found that the main components in the deposit samples were KCl and K 2SO 4, while K 2CO 3, NaCl, Na 2SO 4, Ca(OH) 2 and CaCl 2 were present in smaller concentrations. In addition, deposits from combustion of recycled wood chips contained considerable amounts of ZnCl 2, PbCl 2, ZnO and PbO. Large variations in the chemical composition were observed for different samples and throughout the cross-section of a single sample. The chlorides, in particular NaCl, were present mainly as particles, while the sulfates were more homogeneously distributed in the deposit. The results from this study show that TOF-SIMS analysis of combustion deposits can contribute significantly to an increased understanding of the formation and growth of deposits in combustion reactors.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  6. Scandium separation from tungsten crucibles :

    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.

  7. 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.

  8. 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.

  9. 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.

  10. Drastic Enhancement of Photocatalytic Activities over Phosphoric Acid Protonated Porous g-C3 N4 Nanosheets under Visible Light.

    PubMed

    Shi, Li; Chang, Kun; Zhang, Huabin; Hai, Xiao; Yang, Liuqing; Wang, Tao; Ye, Jinhua

    2016-08-01

    A simple method is developed to fabricate protonated porous graphitic carbon nitride nanosheets (P-PCNNS) by protonation-exfoliation of bulk graphitic carbon nitride (BCN) with phosphoric acid (H3 PO4 ). The H3 PO4 treatment not only helps to exfoliate the BCN into 2D ultrathin nanosheets with abundant micro- and mesopores, endowing P-PCNNS with more exposed active catalytic sites and cross-plane diffusion channels to facilitate the mass and charge transport, but also induces the protonation of carbon nitride polymer, leading to the moderate removal of the impurities of carbon species in BCN for the optimization of the aromatic π-conjugated system for better charge separation without changing its chemical structure. As a result, the P-PCNNS show much higher photocatalytic performance for hydrogen evolution and CO2 conversion than bare BCN and graphitic carbon nitride nanosheets. PMID:27410192

  11. Determination of intracellular nitrate.

    PubMed Central

    Romero, J M; Lara, C; Guerrero, M G

    1989-01-01

    A sensitive procedure has been developed for the determination of intracellular nitrate. The method includes: (i) preparation of cell lysates in 2 M-H3PO4 after separation of cells from the outer medium by rapid centrifugation through a layer of silicone oil, and (ii) subsequent nitrate analysis by ion-exchange h.p.l.c. with, as mobile phase, a solution containing 50 mM-H3PO4 and 2% (v/v) tetrahydrofuran, adjusted to pH 1.9 with NaOH. The determination of nitrate is subjected to interference by chloride and sulphate when present in the samples at high concentrations. Nitrite also interferes, but it is easily eliminated by treatment of the samples with sulphamic acid. The method has been successfully applied to the study of nitrate transport in the unicellular cyanobacterium Anacystis nidulans. PMID:2497740

  12. Fluroide concentration in enamel treated with 50% phosphoric acid and NaF with subsequent decalcification in "acid-gel".

    PubMed

    Bohrer, J; Gedalia, I

    1980-06-01

    Fluoride concentration of enamel surfaces treated with 50% H3PO4, together with high NaF contents or etched with 50% H3PO4 followed by application with a water solution of high NaF content, was examined. In addition, the degree of decalcification and the fluoride content of subsequently incubated enamel samples in acid-gel at 37 degrees C were determined. Generally, incubation highly increased the fluoride contents of the etched and fluoridated (experimental), control (etched only), and untreated (vaseline) enamel samples. An increasing demineralization effect was observed in the samples of the following order: experimental, control, and baseline. It appears does not predispose to an increased caries challenge in vitro.

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

    PubMed

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

    2012-05-01

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

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

    SciTech Connect

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

    1990-09-01

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

  15. 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

  16. Dynamics of the hydrogen and phosphate ions in proton conducting gel/D3PO4 electrolytes: A 2H and 31P nuclear magnetic resonance study

    NASA Astrophysics Data System (ADS)

    Jeffrey, K. R.; Zukowska, G. Z.; Stevens, J. R.

    2003-07-01

    The synthesis and characterization of protonic conducting polymeric gels is motivated by their possible application in various electrochemical devices. Nonaqueous proton-conducting gel electrolytes are being developed for use in various sensors and electrochromic devices operating at ambient temperatures. The electrolyte must have a relatively high conductivity and chemical and physical stability. One method of producing nonaqueous conducting polymeric gel electrolytes is to entrap organic solutions of a strong acid such as H3PO4 in a polymer matrix. Results are reported on the system consisting of phosphoric acid dissolved in N,N-dimethyl formamide (DMF) within a gel network formed with poly(glycidyl methacrylate) (PGMA). Using selective deuteration, the diffusion coefficients for both the deuteron and phosphorus from the phosphoric acid and the DMF are measured by field gradient nuclear magnetic resonance (NMR) techniques. Combining the diffusion with conductivity measurements in the Nernst-Einstein equation leads to a better understanding of the number of charge carriers in the mixture and the temperature dependence of this number. Nuclear spin-lattice relaxation is used as a tool to probe the ion dynamics in these materials. In addition to NMR measurements, the samples have been characterized by electrical conductivity, differential scanning calorimetry, and viscosity measurements. The results show that the Grotthus mechanism involving the hopping of the proton from one molecular site to another, as well as the vehicular mechanism due to the motion of the D2PO4- and D4PO4+ ions are most responsible for the motion of the proton in these electrolytes. The variety of protonation sites in the PGMA/DMF/H3PO4 system is much more diverse that in the previously studied PMMA/PC/D3PO4 system. In the PGMA/DMF/H3PO4 system there are sites on the polymer, DMF and H3PO4.

  17. Carbon-coated Fe3O4 microspheres with a porous multideck-cage structure for highly reversible lithium storage.

    PubMed

    Wang, Yanrong; Zhang, Lei; Wu, Yali; Zhong, Yijun; Hu, Yong; Lou, Xiong Wen David

    2015-04-25

    A novel H3PO4 etching strategy together with subsequent carbon coating has been developed for the synthesis of carbon-coated Fe3O4 microspheres with a porous multideck-cage structure. These carbon-coated Fe3O4 microspheres manifest high specific capacity (∼1100 m h g(-1) at 200 mA g(-1)) and excellent cycling stability for lithium storage.

  18. Textural properties and surface chemistry of lotus stalk-derived activated carbons prepared using different phosphorus oxyacids: adsorption of trimethoprim.

    PubMed

    Liu, Hai; Zhang, Jian; Bao, Nan; Cheng, Cheng; Ren, Liang; Zhang, Chenglu

    2012-10-15

    The preparation of activated carbons (AC-H(x)P(y)O(z)) by four kinds of oxyacids of phosphorus (H(3)PO(4), H(4)P(2)O(7), HPO(3) and H(3)PO(3)) activation of lotus stalk (LS) was studied, with a particular focus on the effect of these H(x)P(y)O(z) on both surface chemistry and porous texture. The XRD analysis of the samples after H(x)P(y)O(z) impregnation showed H(4)P(2)O(7) had the strongest influence on the crystallinity of LS. Thermo gravimetric studies of the pyrolysis of LS-H(x)P(y)O(z) indicated that these H(x)P(y)O(z) had a very different influence on the thermal degradation of LS. The prepared activated carbons were characterized by SEM, N(2) sorption/desorption isotherms, XRD, FTIR and Boehm's titration. Batched sorption studies were performed to compare adsorptive properties of the carbons toward trimethoprim (TMP). The surface area and pore volume of AC-H(3)PO(4) and AC-H(4)P(2)O(7) were much higher than AC-HPO(3) and AC-H(3)PO(3). Boehm's titration results indicated that AC-H(4)P(2)O(7) and AC-H(3)PO(3) possessed more acidic oxygen functionalities than AC-H(3)PO(4) and AC-HPO(3). The structure of the AC-HPO(3) was kept as its starting material after activation. Activation with H(3)PO(3) would result in the aromatization of the carbon. The sorption affinities of TMP follows an order of AC-H(4)P(2)O(7)>AC-H(3)PO(4)>AC-H(3)PO(3)>AC-HPO(3).

  19. The relationship of surface roughness and cell response of chemical surface modification of titanium

    PubMed Central

    Zareidoost, Amir; Ghaseme, Behrooz

    2012-01-01

    Implant surface topography influences osteoblastic proliferation, differentiation and extracellular matrix protein expressions. Previous researches proved that chemical surface modification of titanium implants could be used to improve Bone-to-implant contact. In this study, the surface topography, chemistry and biocompatibility of polished titanium surfaces treated with mixed solution of three acids containing HCl, HF and H3PO4 with different etched conditions for example concentration, time and addition of calcium chloride were studied. Osteoblast cells (MG-63) were cultured on different groups of titanium surfaces. In order to investigate titanium surfaces, SEM, AFM and EDS analyses were carried out. The results showed that surfaces treated with HCl–HF–H3PO4 had higher roughness, lower cytotoxicity level and better biocompatibility than controls. Moreover, addition of calcium chloride into mixed solution of three acids containing HCl, HF and H3PO4 is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry. PMID:22460230

  20. Surface characteristics of dentin experimentally exposed to hydrofluoric acid.

    PubMed

    Pioch, Thomas; Jakob, Heiko; García-Godoy, Franklin; Götz, Hermann; Dörfer, Christof E; Staehle, Hans J

    2003-08-01

    The purpose of this study was to test the effect of hydrofluoric acid (HF) on the surface characteristics of dentin in vitro. Dentin was exposed in 50 human molars and divided into five groups according to different etching schedules: (i) no etching, (ii) 15 s HF, (iii) 15 s H3PO4, (iv) 15 s HF and 15 s H3PO4, (v) 15 s H3PO4 and 15 s HF. Teeth were examined under a scanning electron microscope equipped with energy-dispersive X-ray (EDX) or two layers of fluorescence-labeled primer followed by the composite were applied, and the teeth were sectioned and examined using confocal laser scanning microscopy (CLSM). With scanning electron microscopy, no openings of dentinal tubules were found in groups (i), (ii), and (iv). In group (v) only a few tubules were opened and in group (iii) the smear layer was completely removed and tubules appeared open. The EDX analysis revealed that fluoride was incorporated into the dentin surface when HF was used. With CLSM, distinct hybrid layers could be detected only in group (iii). In group (v) the hybrid layer appeared less established compared with group (iii). No dentin hybridization was found in groups (i), (ii), and (iv). It is concluded that HF has the ability to close the openings of dentin tubules which were opened due to etching by phosphoric acid and cannot dissolve the smear layer.

  1. Treatment of anaerobic digester effluents of nylon wastewater through chemical precipitation and a sequencing batch reactor process.

    PubMed

    Huang, Haiming; Song, Qianwu; Wang, Wenjun; Wu, Shaowei; Dai, Jiankun

    2012-06-30

    Chemical precipitation, in combination with a sequencing batch reactor (SBR) process, was employed to remove pollutants from anaerobic digester effluents of nylon wastewater. The effects of the chemicals along with various Mg:N:P ratios on the chemical precipitation (struvite precipitation) were investigated. When brucite and H(3)PO(4) were applied at an Mg:N:P molar ratio of 3:1:1, an ammonia-removal rate of 81% was achieved, which was slightly more than that (80%) obtained with MgSO(4)·7H(2)O and Na(2)HPO(4)·12H(2)O at Mg:N:P molar ratios greater than the stoichiometric ratio. To further reduce the ammonia loads of the successive biotreatment, an overdose of phosphate with brucite and H(3)PO(4) was applied during chemical precipitation. The ammonia-removal rate at the Mg:N:P molar ratio of 3.5:1:1.05 reached 88%, with a residual PO(4)-P concentration of 16 mg/L. The economic analysis showed that the chemical cost of chemical precipitation could be reduced by about 41% when brucite and H(3)PO(4) were used instead of MgSO(4)·7H(2)O and Na(2)HPO(4)·12H(2)O. The subsequent biological process that used a sequencing batch reactor showed high removal rates of contaminants. The quality of the final effluent met the requisite effluent-discharging standards.

  2. Comparing different salt forms of rotigotine to improve transdermal iontophoretic delivery.

    PubMed

    Ackaert, O W; Eikelenboom, J; Wolff, H M; Bouwstra, J A

    2010-02-01

    The transdermal delivery of a new salt form of the dopamine agonist rotigotine, rotigotine.H(3)PO(4) is presented and compared to rotigotine.HCl. A comparison was made on the level of solubility, passive and iontophoretic delivery. Different aspects of the delivery were investigated: delivery efficiency, maximum flux, donor pH, electro-osmotic contribution and transport number. Changing the salt form from rotigotine.HCl to rotigotine.H(3)PO(4) increases significantly the solubility and rules out the influence of NaCl on the solubility by the absence of the common-ion effect. At low donor concentration, no difference in transdermal delivery was observed between the salt forms. Due to an increase in the maximum solubility of rotigotine.H(3)PO(4), a 170% increase in maximum flux, compared to rotigotine.HCl, was achieved. A balance between solubility and delivery efficiency can be obtained by choosing the correct donor pH between 5 and 6. A slight increase in electro-osmotic contribution and transport number was observed. Using the parameters, determined by modeling the in vitro transport, in vivo simulations revealed that with iontophoresis therapeutic levels can be achieved with a rapid onset time and be maintained in a controlled manner by adjusting the current density. PMID:19969079

  3. Comparing different salt forms of rotigotine to improve transdermal iontophoretic delivery.

    PubMed

    Ackaert, O W; Eikelenboom, J; Wolff, H M; Bouwstra, J A

    2010-02-01

    The transdermal delivery of a new salt form of the dopamine agonist rotigotine, rotigotine.H(3)PO(4) is presented and compared to rotigotine.HCl. A comparison was made on the level of solubility, passive and iontophoretic delivery. Different aspects of the delivery were investigated: delivery efficiency, maximum flux, donor pH, electro-osmotic contribution and transport number. Changing the salt form from rotigotine.HCl to rotigotine.H(3)PO(4) increases significantly the solubility and rules out the influence of NaCl on the solubility by the absence of the common-ion effect. At low donor concentration, no difference in transdermal delivery was observed between the salt forms. Due to an increase in the maximum solubility of rotigotine.H(3)PO(4), a 170% increase in maximum flux, compared to rotigotine.HCl, was achieved. A balance between solubility and delivery efficiency can be obtained by choosing the correct donor pH between 5 and 6. A slight increase in electro-osmotic contribution and transport number was observed. Using the parameters, determined by modeling the in vitro transport, in vivo simulations revealed that with iontophoresis therapeutic levels can be achieved with a rapid onset time and be maintained in a controlled manner by adjusting the current density.

  4. 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.

  5. 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.

  6. Impacts of phosphate amendments on lead biogeochemistry at a contaminated site.

    PubMed

    Cao, Xinde; Ma, Lena Q; Chen, Ming; Singh, Satya P; Harris, Willie G

    2002-12-15

    Soil amendments can be used to cost-effectively reduce the bioavailability and mobility of toxic metals in contaminated soils. In this study a field demonstration was conducted at a Pb-contaminated site to evaluate the effectiveness of P-induced Pb immobilization. Phosphate was applied at a 4.0 molar ratio of P to Pb with three treatments: T1, 100% of P from H3PO4; T2, 50% P from H3PO4 + 50% P from Ca(H2PO4)2; and T3, 50% P from H3PO4 + 5% phosphate rock. Phosphate amendments effectively transformed soil Pb from the nonresidual (sum of exchangeable, carbonate, Fe/Mn, and organic) to the residual fraction, with residual Pb increase by 19-48% for T1, 22-50% for T2, and 11-55% for T3, respectively. Lead immobilization was attributed to the P-induced formation of chloropyromorphite [Pb10(PO4)6Cl2], which was identified in the surface soil, subsurface soil, and plant rhizosphere soil. Occurrence of chloropyromorphite was evident 220 days after P addition for T1 and T2 treatments and 330 days for T3. Visual MINTEQ model and activity-ratio diagram indicated that lead phosphate minerals controlled Pb2+ activities in the P-treated soils. Phosphate treatments significantly reduced Pb translocation from the roots to the shoots in the St. Augustine grass (Stenotaphrum secundatum), possibly via the formation of chloropyromorphite on the cell walls of roots. This field observation suggested that P amendments are efficient in reducing Pb mobility via in situ formation of insoluble chloropyromorphite minerals at a field setting. Lead immobilization shows a long-term stability. A mixture of H3PO4 and phosphate rock yields the best overall results for in situ Pb immobilization, with less soil pH change and less P leaching. Application of combined H3PO4 with phosphate rock may provide an effective alternative to the current phosphate remediation technologies for contaminated soils.

  7. 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

  8. 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.

  9. Following the electroreduction of uranium dioxide to uranium in LiCl-KCl eutectic in situ using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Brown, L. D.; Abdulaziz, R.; Jervis, R.; Bharath, V. J.; Atwood, R. C.; Reinhard, C.; Connor, L. D.; Simons, S. J. R.; Inman, D.; Brett, D. J. L.; Shearing, P. R.

    2015-09-01

    The electrochemical reduction of uranium dioxide to metallic uranium has been investigated in lithium chloride-potassium chloride eutectic molten salt. Laboratory based electrochemical studies have been coupled with in situ energy dispersive X-ray diffraction, for the first time, to deduce the reduction pathway. No intermediate phases were identified using the X-ray diffraction before, during or after electroreduction to form α-uranium. This suggests that the electrochemical reduction occurs via a single, 4-electron-step, process. The rate of formation of α-uranium is seen to decrease during electrolysis and could be a result of a build-up of oxygen anions in the molten salt. Slow transport of O2- ions away from the UO2 working electrode could impede the electrochemical reduction.

  10. Effects of the simultaneous application of potassium and calcium on the soil-to-Chinese cabbage transfer of radiocesium and radiostrontium.

    PubMed

    Choi, Yong-Ho; Lim, Kwang-Muk; Jun, In; Keum, Dong-Kwon; Lee, Chang-Woo

    2008-12-01

    Pot experiments were carried out in a greenhouse to investigate how effectively the transfer of radiocesium and radiostrontium from soil to Chinese cabbage could be reduced by applying K and Ca simultaneously to the soil. The sources of these elements were KCl and Ca(OH)(2) at agrochemical grades. Varying dosages of K and Ca were tested for an acid loamy soil treated with a mixed solution of (137)Cs and (85)Sr at two different times - 3 d before sowing and 32 d after sowing. For the pre-sowing deposition, the soil-to-plant transfer of (137)Cs decreased sharply with increasing dosages of K and Ca (K/Ca, g m(-2)) from 4.8/46 up to 22.4/215 but the (85)Sr transfer had the greatest reduction at a dosage of 12.8/123. At this dosage, an about 60% reduction occurred for each radionuclide. Plant growth was inhibited from the dosage of 22.4/215, above which all the plants died young. Both dosages of 4.8/46 and 12.8/123 tested following the growing-time deposition produced around 95% reductions for (137)Cs and 50% reductions for (85)Sr. In the second year after the 12.8/123 applications, the effects for (85)Sr were almost the same as in the first year, whereas those for (137)Cs were diminished slightly for the pre-sowing deposition and markedly for the growing-time deposition. Considerably (K) or slightly (Ca) higher doses than 12.8/123 would be allowable for the maximum TF reductions achievable without a growth inhibition.

  11. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  12. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  13. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also... meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 52, which is incorporated...

  14. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  15. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  16. Calcium hydroxide: its role in the fracture of tricalcium silicate paste.

    PubMed

    Berger, R L

    1972-02-11

    The large areas of crystalline calcium hydroxide [Ca(OH)(2)] formed during the hydration of tricalcium silicate (Ca(3)SiO(5)) correspond to low-porosity regions in the hydrated paste. During the early stage of hydration, areas between Ca(OH)(2) crystals which consist of Ca(3)SiO(5) particles bonded together by calcium silicate hydrate represent the high-porosity portion of the paste. Because of the presence of Ca(OH)(2), fracture in the hardened paste during this period propagates preferentially through the areas bonded by the calcium silicate hydrate phase and around the Ca(OH)(8), crystals. Calcium hydroxide also acts as a crack arrester. The influence of Ca(OH)(2) on fracture diminishes with increased hydration.

  17. Clinical and radiographic assessment of mineral trioxide aggregate and calcium hydroxide as apexification agents in traumatized young permanent anterior teeth: A comparative study

    PubMed Central

    Damle, S. G.; Bhattal, Hiteshwar; Damle, Dhanashree; Dhindsa, Abhishek; Loomba, Ashish; Singla, Sumit

    2016-01-01

    Background: To evaluate and compare the efficacy of mineral trioxide aggregate (MTA) and traditionally used calcium hydroxide (Ca(OH)2) in inducing root end formation of immature roots of traumatized young permanent anterior teeth. Materials and Methods: The study was carried out on 22 nonvital, immature permanent maxillary incisors. Samples were allotted into two groups - Group I MTA and Group II Ca(OH)2 Success rate was determined based upon the time duration required for apical barrier formation. The canals were obturated using gutta-percha points in MTA group, after 24 h, whereas in Ca(OH)2 group, obturation was carried out after radiographic confirmation of the apical barrier. The clinical and radiographic evaluation was carried out at a follow-up periods of 3, 6, and 9 months and statistical analysis was carried out by SPSS version 15.0 statistical analysis software (Chi-square test and fisher exact test). Results: In MTA Group, barrier formation was observed in 90.90% of the patients after 9 months whereas in Ca(OH)2 Group, the same was observed in 81.81%. The mean time required for barrier formation in MTA group was 4.90 months and 5.33 months in Ca(OH)2 group. Conclusion: MTA and Ca(OH)2, as medicaments for apexification, were comparable in terms of the evaluation parameters. However, MTA was beneficial in terms of immediate obturation of immature roots with wide open apices. PMID:27274351

  18. A histologic assessment of a HYBENX® oral tissue decontaminant in vital pulp therapy in dogs.

    PubMed

    Rohrer, M D; Prasad, H S; Savord, E G

    2016-01-01

    The aim of this study was to assess HYBENX® Oral Tissue Decontaminant (HOTD) in treating vital pulp exposure in a canine model. The use of HOTD solution was compared to an accepted and standard regimen for vital pulp exposure, an application of a commercial calcium hydroxide product (Ca(OH)2). Both control and experimental treatments were followed by restoration with a commercial zinc oxide and eugenol obtundant intermediate restorative material and thermal insulator (ZOE). At 7 days there was 100% pulp vitality with HOTD and 50% with Ca(OH)2. New dentin formation was seen in 62.5% of the HOTD treated pulps and none of the Ca(OH)2 treatment group. The vital pulp exposures at day 21 post treatment with HOTD also showed significant improvement over Ca(OH)2 in the presence of odontoblasts, new dentin formation and pulp survivability. The presence of odontoblasts and new dentin was noted in 71% of the HOTD cases versus 50% of the survivable Ca(OH)2 cases. Furthermore, 100% of HOTD cases had vital pulps versus 62.5% of Ca(OH)2 cases. The 60-day specimens of both experimental and control techniques exhibited histologically similar appearances and were similar in outcomes. HOTD treatment at day 7 showed a significant positive difference, both in the formation of new dentin and tooth vitality. HOTD proved better for the post 21-day specimens and equivalent for the 60-day pulp specimens with no evidence of untoward tissue reactions or results.

  19. 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.

  20. Fabrication of Lotus-Type Porous Al-Si Alloys Using Thermal Decomposition Method Combined with Mold Casting and Continuous Casting Techniques

    NASA Astrophysics Data System (ADS)

    Kim, Tae Bum; Jung, Taek Kyun; Kim, Yong Hwan; Kim, Taek Soo; Hyun, Soong Keun

    2013-05-01

    Porous Al-Si alloys with directional pores were fabricated using thermal decomposition methods combined with mold casting and continuous casting techniques. The melt of Al-14 mass pct Si alloy was unidirectionally solidified in argon atmospheres by the mold casting or continuous casting technique. Ca(OH)2 compound was added into the melt as a source of hydrogen which forms pores during the solidification. In order to clarify the pore formation behavior, the effects of transfer velocity, ambient argon pressure, the amount, and the morphology of Ca(OH)2 compounds on the porosity were investigated. It was found that the porosity decreases with the increasing transfer velocity (solidification velocity). The pores are formed under the argon pressure of 1 kPa, while not being formed under the pressure higher than 20 kPa. The porosity increases with the increasing amount of Ca(OH)2 when the compacted Ca(OH)2 pellets are used, while pores are not formed when Ca(OH)2 powders are used because of the rapid decomposition of Ca(OH)2.

  1. 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.

  2. Fermentable sugars recovery from lignocellulosic waste-newspaper by catalytic hydrolysis.

    PubMed

    Orozco, Angela M; Al-Muhtaseb, Ala'a H; Rooney, David; Walker, Gavin M; Aiouache, Farid; Ahmad, Mohammad

    2013-01-01

    The urgent need for alternative renewable energies to supplement petroleum-based fuels and the reduction of landfill sites for disposal of solid wastes makes it increasingly attractive to produce inexpensive biofuels from the organic fraction of the municipal solid waste. Therefore, municipal waste in the form of newspaper was investigated as a potential feedstock for fermentable sugars production. Hydrolysis of newspaper by dilute phosphoric acid was carried out in autoclave Parr reactor, where reactor temperature and acid concentration were examined. Xylose concentration reached a maximum value of 14 g/100 g dry mass corresponding to a yield of 94% at the best identified conditions of 2.5 wt% H3PO4, 135 degrees C, 120 min reaction time, and at 2.5 wt% H3PO4, 150 degrees C, and 60 min reaction time. For glucose, an average yield of 26% was obtained at 2.5 wt% H3PO4, 200 degrees C, and 30 min. Furfural and 5-hydroxymethylfurfural (HMF) formation was clearly affected by reaction temperature, where the higher the temperature the higher the formation rate. The maximum furfural formed was an average of 3 g/100 g dry mass, corresponding to a yield of 28%. The kinetic study of the acid hydrolysis was also carried out using the Saeman and the two-fraction models. It was found for both models that the kinetic constants (K) depend on the acid concentration and temperature. The degradation of HMF to levulinic acid is faster than the degradation of furfural to formic acid. Also, the degradation rate is higher than the formation rate for both inhibitors when degradation is observed.

  3. 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.

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

    PubMed

    Brown, Robert; Stuart, Scott A; 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.

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

    PubMed Central

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

    2015-01-01

    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 non-parametric 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 due to 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. PMID:25851653

  6. Improved method for isotopic and quantitative analysis of dissolved inorganic carbon in natural water samples.

    PubMed

    Assayag, Nelly; Rivé, Karine; Ader, Magali; Jézéquel, Didier; Agrinier, Pierre

    2006-01-01

    We present here an improved and reliable method for measuring the concentration of dissolved inorganic carbon (DIC) and its isotope composition (delta(13)C(DIC)) in natural water samples. Our apparatus, a gas chromatograph coupled to an isotope ratio mass spectrometer (GCIRMS), runs in a quasi-automated mode and is able to analyze about 50 water samples per day. The whole procedure (sample preparation, CO(2(g))-CO(2(aq)) equilibration time and GCIRMS analysis) requires 2 days. It consists of injecting an aliquot of water into a H(3)PO(4)-loaded and He-flushed 12 mL glass tube. The H(3)PO(4) reacts with the water and converts the DIC into aqueous and gaseous CO(2). After a CO(2(g))-CO(2(aq)) equilibration time of between 15 and 24 h, a portion of the headspace gas (mainly CO(2)+He) is introduced into the GCIRMS, to measure the carbon isotope ratio of the released CO(2(g)), from which the delta(13)C(DIC) is determined via a calibration procedure. For standard solutions with DIC concentrations ranging from 1 to 25 mmol . L(-1) and solution volume of 1 mL (high DIC concentration samples) or 5 mL (low DIC concentration samples), delta(13)C(DIC) values are determined with a precision (1sigma) better than 0.1 per thousand. Compared with previously published headspace equilibration methods, the major improvement presented here is the development of a calibration procedure which takes the carbon isotope fractionation associated with the CO(2(g))-CO(2(aq)) partition into account: the set of standard solutions and samples has to be prepared and analyzed with the same 'gas/liquid' and 'H(3)PO(4)/water' volume ratios. A set of natural water samples (lake, river and hydrothermal springs) was analyzed to demonstrate the utility of this new method. PMID:16810706

  7. High temperature polybenzimidazole membrane electrode assemblies using pyridine-polybenzimizazole as catalyst layer binder

    NASA Astrophysics Data System (ADS)

    Su, Po-Hao; Cheng, Joy; Li, Jia-Fen; Liao, Yi-Hsiang; Yu, T. Leon

    2014-08-01

    We synthesize four pyridine-polybenzimidazoles (PyPBIs) and one polybenzimidazole (PBI) from a tetramin monomer (i.e., 3,3‧-diamino benzidine (DABZ)) and two dicarboxylic acid monomers (i.e., isophthalic acid (IPA) and 2,6-pyridinedicarboxylic acid (PyA)) with PyA/IPA molar ratios of 6/4 (i.e., PyPBI-64), 5/5 (i.e., PyPBI-55), 4/6 (i.e., PyPBI-46), 3/7 (i.e., PyPBI-37), and 0/1 (i.e., PBI-11). The PyPBIs and PBI with molecular weight of ∼1.0-1.3 × 10-4 g mol-1 are used as Pt-C (Pt on carbon support) binders for fabricating gas diffusion electrodes (GDEs) and are doped with H3PO4 to prepare membrane electrode assemblies (MEAs). We demonstrate that both the H3PO4 loading of the GDE and the fuel cell performance of the MEA at 160 °C with unhumidified H2/O2 fuel increase with the increase of PyA monomer content of the PyPBI (or PBI) binder in the GDEs according to the sequence of PBI-11 < PyPBI-37 < PyPBI-46 < PyPBI-55 < PyPBI-64. The higher PyA content PyPBI provides more binding sites for H3PO4 in GDE and enhances fuel cell performance.

  8. Effect of Phosphoric Acid Concentration on the Characteristics of Sugarcane Bagasse Activated Carbon

    NASA Astrophysics Data System (ADS)

    Adib, M. R. M.; Suraya, W. M. S. W.; Rafidah, H.; Amirza, A. R. M.; Attahirah, M. H. M. N.; Hani, M. S. N. Q.; Adnan, M. S.

    2016-07-01

    Impregnation method is one of the crucial steps involved in producing activated carbon using chemical activation process. Chemicals employed in this step is effective at decomposing the structure of material and forming micropores that helps in adsorption of contaminants. This paper explains thorough procedures that have been involved in producing sugarcane bagasse activated carbon (SBAC) by using 5%, 10%, 20%, 30% phosphoric acid (H3PO4) during the impregnation step. Concentration of H3PO4 used in the process of producing SBAC was optimized through several tests including bulk density, ash content, iodine adsorption and pore size diameter and the charactesristic of optimum SBAC produced has been compared with commercial activated carbon (CAC). Batch study has been carried out by using the SBAC produced from optimum condition to investigate the performance of SBAC in removal of turbidity and chemical oxygen demand (COD) from textile wastewater. From characteristic study, SBAC with 30% H3PO4 has shown the optimum value of bulk density, ash content, iodine adsorption and pore size diameter of 0.3023 g cm-3, 4.35%, 974.96 mg/g and 0.21-0.41 µm, respectively. These values are comparable to the characteristics of CAC. Experimental result from the batch study has been concluded that the SBAC has a promising potential in removing turbidity and COD of 75.5% and 66.3%, respectively which was a slightly lower than CAC which were able to remove 82.8% of turbidity and 70% of COD. As a conclusion, the SBAC is comparable with CAC in terms of their characteristics and the capability of removing contaminants from textile wastewater. Therefore, it has a commercial value to be used as an alternative of low-cost material in producing CAC.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

  11. 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

  12. Absolute shielding scale for 31P from gas-phase NMR studies

    NASA Astrophysics Data System (ADS)

    Jameson, Cynthia J.; De Dios, Angel; Keith Jameson, A.

    1990-04-01

    Differences in the 31P nuclear shielding in the zero-pressure limit have been measured in seven compounds. An absolute 31P shielding scale based on the PH 3 molecular beam data is established and the absolute shielding of the standard liquid reference (85% aqueous H 3PO 4) is found to be 328.35 ppm, based on PH 3 being 594.45 ± 0.63 ppm. Comparisons with ab initio calculations show that calculations using local origins (the IGLO method) are in good agreement with experiment.

  13. Quantum-chemical studies of dimethylformamide 1 : 1 complexes with phosphoric acid

    NASA Astrophysics Data System (ADS)

    Krest'yaninov, M. A.; Kiselev, M. G.; Safonova, L. P.

    2012-12-01

    The structures of two phosphoric acid conformations, dimethylformamide (DMFA), four protonated DMFA forms, and nine DMFA-H3PO4 complexes in which the proton acceptor is a oxygen or nitrogen atom of the DMFA molecule are optimized by DFT/B3LYP using the 6-31++G( d, p) basis set. The structural changes in DMFA that occur upon its protonation are discussed. The stabilization energy and transferred charge values upon the formation of a hydrogen bond are calculated for all of the studied complexes by means of NBO analysis. The potential energy surface is scanned to study the possibility of proton transfer.

  14. In situ templated synthesis of anatase single-crystal nanotube arrays.

    PubMed

    Zhao, Jianling; Wang, Xiaohui; Sun, Tieyu; Li, Longtu

    2005-10-01

    Anatase single-crystal nanotubes were obtained using an in situ templated method. First, highly ordered titania arrays were formed through an anodization process in H(3)PO(4) electrolytes containing 0.5 wt% HF. Under optimized conditions titania nanotubes with a diameter of up to 100 nm and a length of up to 1.1 microm were prepared. Second, the crystallization and stability of the titania nanotubes were studied in air at elevated temperatures. Anatase single-crystal nanotubes were fabricated after annealing the sample in air at 450 degrees C. The anatase single-crystal structure was verified by selected area diffraction pattern and HRTEM images.

  15. Specific Anion Effects on the Kinetics of Iodination of Acetone.

    PubMed

    Lo Nostro, Pierandrea; Mazzini, Virginia; Ninham, Barry W; Ambrosi, Moira; Dei, Luigi; Baglioni, Piero

    2016-08-18

    Specific ion effects on the kinetics of iodination of acetone in an acidic medium are investigated by UV/Vis spectrophotometry as a function of nature of the acid and temperature. The results indicate that the order of the reaction with respect to acetone is practically unaffected by the composition of the acid while the value of the mixed constant k1 K increases according to the sequence HBrH3 PO4 . The results are discussed in terms of the hydration free energy and size of the anion and of the interaction between the cationic intermediate and the anion. PMID:27171120

  16. Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals

    NASA Astrophysics Data System (ADS)

    Govindaiah, T. N.; Sreepad, H. R.; Sridhar, K. N.; Sridhara, G. R.; Nagaraja, N.

    2015-06-01

    A binary mixture of abietic acid and orthophosphoric acid (H3PO4) exhibits co-existence of biphasic region of Nematic+Isotropic (N+I), lyotropic Nematic (ND) and Smectic-G (SmG) phases. The mixture exhibits N+I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I→N+I→N→SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.

  17. 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

  18. 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

  19. Immunolocalization of fibronectin during reparative dentinogenesis in rat molor teeth after pulp capping with mineral trioxide aggregate or calcium hydroxide.

    PubMed

    Bal, Cenkhan; Oztas, Nurhan; Cincik, Mehmet; Baris, Emre

    2011-11-01

    The aim of this study was to evaluate the immunolocalization of fibronectin during reparative dentinogenesis in rat teeth after pulp capping with mineral trioxide aggregate (MTA) or calcium hydroxide (Ca(OH)2). The pulps of 72 upper and lower first molar teeth from 18 male Wistar rats were experimentally exposed. The pulps were capped with MTA or (Ca(OH)2); final restoration followed with zinc oxide and eugenol cement. The animals were euthanized at, respectively, one, three, seven and fourteen days postoperatively. At day one, all groups showed varying degrees of inflammation, from mild to severe. There was no positive reaction for fibronectin at day one. After three days, a partial acute pulpitis was observed in the Ca(OH)2 group. There was less inflammation in the MTA group (p<0.05), and a layer of fibrin barrier was observed along the pulp walls of the MTA material. The layer of fibrodentin formation showed positive reaction for fibronectin. At seven days, the Ca(OH)2 group showed mild inflammation and demonstrated more immunostaining for fibronectin than the Ca(OH)2 group (p<0.05) at three days. Pulps capped with MTA at seven days showed thicker fibrin barrier formation than the MTA group at three days and more immunostaining for fibronectin in whole groups (p<0.05). At fourteen days, there was no positive reaction for fibronectin in either the MTA or Ca(OH)2 group. It seems MTA showed better biocompability properties with the dental pulp tissue, inducing the expression of reparative molecule fibronectin compared with Ca(OH)2. Therefore, MTA may be a better choice for pulp capping procedures. PMID:22338817

  20. 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

  1. A comparison of the pulpal response to freeze-dried bone, calcium hydroxide, and zinc oxide-eugenol in primary teeth in two cynomolgus monkeys.

    PubMed

    Fadavi, S; Anderson, A W

    1996-01-01

    This study assessed the pulp healing response to human freeze-dried bone (FDB) in two cynomolgus monkeys using 36 noncarious primary teeth pulpotomized and randomly assigned to three medicaments. FDB was applied on the pulp stumps and covered with sterile tin foil as experimental group. The two other groups received either calcium hydroxide [Ca(OH)2], or IRM (reinforced ZOE). All teeth were restored with amalgam. One animal was sacrificed at 6 weeks and the other 6 months after treatment. Teeth were extracted and placed in 10% formalin. Histological evaluation indicated that 100% of teeth treated with FDB had vital pulps compared with 75% of the Ca(OH)2 group after 6 weeks. Dentin bridges were present in 87.5% of FDB versus 75% of Ca(OH)2 group. Inflammatory cells were absent or mild in 100% of FDB-treated versus 75% of the Ca(OH)2 group. After 6 months, 83.3% of FDB-treated teeth had vital pulps compared with the Ca(OH)2 group, which showed 100% pulpal necrosis. In FDB-treated pulps, 100% of teeth showed dentin bridges versus 50% of teeth treated with Ca(OH)2. Inflammatory cells were absent or mildly present in 83.3% of FDB-treated teeth while 100% of Ca(OH)2 showed moderate to severe inflammation. IRM-treated teeth all showed pulpal necrosis after 6 months. We concluded that FDB was superior to calcium hydroxide in treating primary pulp dentition in cynomolgus monkeys.

  2. 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.

  3. Effect of different struvite crystallization methods on gaseous emission and the comprehensive comparison during the composting.

    PubMed

    Jiang, Tao; Ma, Xuguang; Yang, Juan; Tang, Qiong; Yi, Zhigang; Chen, Maoxia; Li, Guoxue

    2016-10-01

    This study compared 4 different struvite crystallization process (SCP) during the composting of pig feces. Four combinations of magnesium and phosphate salts (H3PO4+MgO (PMO), KH2PO4+MgSO4 (KPM), Ca(H2PO4)2+MgSO4 (CaPM), H3PO4+MgSO4 (PMS)) were assessed and were also compared to a control group (CK) without additives. The magnesium and phosphate salts were all supplemented at a level equivalent to 15% of the initial nitrogen content on a molar basis. The SCP significantly reduced NH3 emission by 50.7-81.8%, but not the N2O. Although PMS group had the lowest NH3 emission rate, the PMO treatment had the highest struvite content in the end product. The addition of sulphate decreased CH4 emission by 60.8-74.6%. The CaPM treatment significantly decreased NH3 (59.2%) and CH4 (64.9%) emission and yielded compost that was completely matured. Due to its effective performance and low cost, the CaPM was suggested to be used in practice. PMID:26927235

  4. Surface Characteristics and Electrochemical Impedance Investigation of Spark-Anodized Ti-6Al-4V Alloy

    NASA Astrophysics Data System (ADS)

    Garsivaz jazi, M. R.; Golozar, M. A.; Raeissi, K.; Fazel, M.

    2014-04-01

    In this study, the surface characteristic of oxide films on Ti-6Al-4V alloy formed by an anodic oxidation treatment in H2SO4/H3PO4 electrolyte at potentials higher than the breakdown voltage was evaluated. Morphology of the surface layers was studied by scanning electron microscope. The results indicated that the diameter of pores and porosity of oxide layer increase by increasing the anodizing voltage. The thickness measurement of the oxide layers showed a linear increase of thickness with increasing the anodizing voltage. The EDS analysis of oxide films formed in H2SO4/H3PO4 at potentials higher than breakdown voltage demonstrated precipitation of sulfur and phosphor elements from electrolyte into the oxide layer. X-ray diffraction was employed to exhibit the effect of anodizing voltage on the oxide layer structure. Roughness measurements of oxide layer showed that in spark anodizing, the Ra and Rz parameters would increase by increasing the anodizing voltage. The structure and Corrosion properties of oxide layers were studied using electrochemical impedance spectroscopy (EIS) techniques, in 0.9 wt.% NaCl solution. The obtained EIS spectra and their interpretation in terms of an equivalent circuit with the circuit elements indicated that the detailed impedance behavior is affected by three regions of the interface: the space charge region, the inner compact layer, and outer porous layer.

  5. Two-dimensional correlation analysis to study variation of near-infrared water absorption bands in the presence of inorganic acids

    NASA Astrophysics Data System (ADS)

    Chang, Kyeol; Jung, Young Mee; Chung, Hoeil

    2014-07-01

    Two-dimensional (2D) correlation analysis has been utilized to investigate NIR water bands perturbed by the presence of four different inorganic acids individually: HCl, H2SO4, H3PO4, and HNO3. The observed spectral variation in the 9000-7700 cm-1 range was mainly due to interaction of dissociated H3O+ and corresponding anions with the vibration of water in a hydrogen bonding network. 2D correlation analysis of NIR spectra acquired from sample solutions (concentration range: 0.2-1.0 M) showed that individual acids differently influenced water vibration. In addition, unforeseen spectral variations under the water band that were difficult to identify with corresponding raw NIR spectra were clearly observed. Based on the asynchronous correlation analysis, three underlying individual variations occurred for HCl under the 8718 cm-1 band. Only two asynchronous correlations were observed for H2SO4 and H3PO4. The 2D correlation features of HNO3 were distinctly different from those of the other three acids due to an additional spectral feature caused by direct absorption by NO3-. The dissimilar influence of the selected acids on water vibration was confirmed by NIR spectroscopy combined with 2D correlation analysis. Partial least squares (PLS) loadings from each case were compared to examine the difference in weights that were constructed to follow the corresponding concentration changes.

  6. 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.

  7. Osteoconductivity of hydrophilic microstructured titanium implants with phosphate ion chemistry.

    PubMed

    Park, Jin-Woo; Jang, Je-Hee; Lee, Chong Soo; Hanawa, Takao

    2009-07-01

    This study investigated the surface characteristics and bone response of titanium implants produced by hydrothermal treatment using H(3)PO(4), and compared them with those of implants produced by commercial surface treatment methods - machining, acid etching, grit blasting, grit blasting/acid etching or spark anodization. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, contact angle measurement and stylus profilometry. The osteoconductivity of experimental implants was evaluated by removal torque testing and histomorphometric analysis after 6 weeks of implantation in rabbit tibiae. Hydrothermal treatment with H(3)PO(4) and subsequent heat treatment produced a crystalline phosphate ion-incorporated oxide (titanium oxide phosphate hydrate, Ti(2)O(PO(4))(2)(H(2)O)(2); TiP) surface approximately 5microm in thickness, which had needle-like surface microstructures and superior wettability compared with the control surfaces. Significant increases in removal torque forces and bone-to-implant contact values were observed for TiP implants compared with those of the control implants (p<0.001). After thorough cleaning of the implants removed during the removal torque testing, a considerable quantity of attached bone was observed on the surfaces of the TiP implants. PMID:19332400

  8. Kinetics of enzyme-catalyzed hydrolysis of steam-exploded sugarcane bagasse.

    PubMed

    Aguiar, Rodrigo Souza; Silveira, Marcos Henrique Luciano; Pitarelo, Ana Paula; Corazza, Marcos Lucio; Ramos, Luiz Pereira

    2013-11-01

    This work presents the experimental kinetic data and the fractal modeling of sugarcane bagasse steam treatment and enzymatic hydrolysis. Sugarcane bagasse (50 wt% moisture) was pretreated by autohydrolysis at 210 °C for 4 min. Acid catalysis involved the use of 9.5mg g(-1) of H2SO4 or H3PO4 in relation to the substrate dry mass at these same pretreatment conditions. Unwashed, water-washed and alkali-washed substrates were hydrolyzed at 2.0 wt% using 8 and 15 FPU g(-1) (108.22 and 199.54 mg/g) total solids of a Celluclast 1.5 L and Novozym 188 mixture (Novozymes). The fractal kinetic modeling was used to describe the effect of pretreatment and both washing processes on substrate accessibility. Water and/or alkali washing was not strictly necessary to achieve high hydrolysis efficiencies. Also, the fractal model coefficients revealed that H3PO4 was a better pretreatment catalyst under the experimental conditions used in this study, resulting in the most susceptible substrates for enzymatic hydrolysis.

  9. Traveling Wave Ion Mobility Mass Spectrometry and Ab Initio Calculations of Phosphoric Acid Clusters

    NASA Astrophysics Data System (ADS)

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

    Positive and negative ion electrospray mass spectra obtained from 50 mM phosphoric acid solutions presented a large number of phosphoric acid clusters: [(H3PO4)n + zH] z+ or [(H3PO4)n - zH] z- , with n up to 200 and z up to 4 for positively charged clusters, and n up to 270 and z up to 7 for negatively charged cluster ions. Ion mobility experiments allowed very explicit separation of the different charge states. Because of the increased pressures involved in ion mobility experiments, dissociation to smaller clusters was observed both in the trap and transfer areas. Voltages along the ion path could be optimized so as to minimize this effect, which can be directly associated with the cleavage of hydrogen bonds. Having excluded the ion mobility times that resulted from dissociated ions, each cluster ion appeared at a single drift time. These drift times showed a linear progression with the number of phosphoric atoms for cluster ions of the same charge state. Cross section calculations were carried out with MOBCAL on DFT optimized geometries with different hydrogen locations and with three types of atomic charges. DFT geometry optimizations yielded roughly spherical structures. Our results for nitrogen gas interaction cross sections showed that values were dependent on the atomic charges definition used in the MOBCAL calculation. This pinpointed the necessity to define a clear theoretical framework before any comparative interpretations can be attempted with uncharacterized compounds.

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

    PubMed Central

    Hibino, Takashi; Kobayashi, Kazuyo; Nagao, Masahiro; Kawasaki, Shinji

    2015-01-01

    Expanding the range of supercapacitor operation to temperatures above 100°C is important because this would enable capacitors to operate under the severe conditions required for next-generation energy storage devices. In this study, we address this challenge by the fabrication of a solid-state supercapacitor with a proton-conducting Sn0.95Al0.05H0.05P2O7 (SAPO)-polytetrafluoroethylene (PTFE) composite electrolyte and a highly condensed H3PO4 electrode ionomer. At a temperature of 200°C, the SAPO-PTFE electrolyte exhibits a high proton conductivity of 0.02 S cm−1 and a wide withstanding voltage range of ±2 V. The H3PO4 ionomer also has good wettability with micropore-rich activated carbon, which realizes a capacitance of 210 F g−1 at 200°C. The resulting supercapacitor exhibits an energy density of 32 Wh kg−1 at 3 A g−1 and stable cyclability after 7000 cycles from room temperature to 150°C. PMID:25600936

  11. A novel controllable synthesis of silica nanotube arrays with ultraviolet photoluminescence

    NASA Astrophysics Data System (ADS)

    Hu, Mingzhe; Liu, Yinglin; Gu, Haoshuang; Yu, Rong; MacManus-Driscoll, Judith L.; Robinson, Adam P.

    2009-07-01

    The synthesis of large-scale one-dimensional silica nanotube (SNT) arrays embedded in Si substrate is demonstrated by using the combination of AAO template mask and Ar ion milling technique. The geometry of the SNTs could be precisely controlled by the process parameters, which included that the SNT diameter and the interpore distance were controlled by AAO anodization voltage and H 3PO 4 pore widening time, while the length of SNT was controlled by ion milling time and AAO aspect ratio. Also, the SNT fabrication parameters could be related to their photoluminescence (PL) emitting properties, when anodized at 40 V, pore widening in H 3PO 4 acid for 70 min and ion milled for 5 min, a strong intensity and stable ultraviolet (UV) light of 3.25 eV (381 nm) emitted from the SNTs under the excitation of 266 nm laser, which could be assumed arising from twofold coordinated silicon lone pair centers in the oxygen deficiency SNTs. The present fabrication of SNT arrays presents a novel method for intensity and frequency adjustable ultraviolet optoelectronic devices.

  12. a Novel Blackening Method of Preparing Ultra-Black Ni-P Coatings: Effect of Process Parameters on Morphology and Optical Property

    NASA Astrophysics Data System (ADS)

    Jin, Yongzhong; Yang, Kui; Zeng, Xianguang; Fu, Qingshan

    2015-01-01

    Ni-P ultra-black coatings were prepared by a novel blackening method of anodic oxidation in nonoxidizing acid media. The effect of the applied voltage, concentration of H3PO4 and anodization time on the microstructure and optical property of blackened coatings was investigated. The results show that the applied voltage plays the most important role during the formation of the ultra-black coatings. The concentration of H3PO4 is the next-important factor, then anodization time. The optimum process parameter for obtaining ultra-black coatings is at 0.9 V in 3 mol/L for 40 min, in which the reflectance is only 0.14-0.21% in the visible region. The low reflectance is mainly attributable to the unique array structure of conical cavities ranging 1-3 μm in size, in which the innumerable tiny pits distribute on the cavity wall. In contrast, the black coatings etched by chemical etching method by strong oxidizing acid (HNO3) have larger conical cavities (10-20 μm) with smooth cavity wall, and thus lead to higher reflectance of 0.69-2.44%.

  13. 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.

  14. Shear bond strength of resin to acid/pumice-microabraded enamel.

    PubMed

    Royer, M A; Meiers, J C

    1995-01-01

    The effect of enamel microabrasion techniques consisting of either 18% hydrochloric acid in pumice or a commercially available abrasive/10% hydrochloric acid mixture, PREMA, on composite/enamel shear bond strengths was investigated. Sixty extracted third molars had the bonding surface flattened and were divided into six treatment groups (n=10) with the enamel treated prior to bonding as follows: Group 1-- untreated; Group 2--37% phosphoric acid etched for 30 seconds; Group 3--18% hydrochloric acid/pumice mixture applied for five 20-second treatments; Group 4--similar to Group 3 with additional 37% phosphoric acid etch; Group 5--treated with PREMA compound applied for five 20-second treatments; Group 6--similar to Group 5 treatment with additional 37% phosphoric acid. Herculite XR composite resin was then bonded to all samples using a VLC unit. Samples were tested in shear, and fractured enamel surfaces were evaluated using light microscopy to determine the enamel-to-resin failures. Resin bond strengths to microabraded and H3PO4-etched enamel were similar to bond strengths of untreated H3PO4-etched enamel and were significantly better than bond strengths to PREMA-treated or unetched enamel.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  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. 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.

  2. Evaluation of a no-rinse enamel conditioning prior to sealant application: an in vitro study of comparison to traditional etching technique.

    PubMed

    Vijayaraghavan, T V; Hsiao, J Y; Moss, S J

    1995-01-01

    Moisture contamination is a major factor in sealant application, often determining clinical success or failure. A new enamel conditioner using HNO3 (2.5%) has been introduced that does not require a water rinse after etching. The aim of this study is to compare etching characteristics using sealant retention from shear bond strength tests for traditional etch conditioning using H3PO4 (37%) and the HNO3 (2.5%) conditioner with and without a water rinse. We used 28 crown-intact extracted human teeth. We evaluated eight shear bond strength tests per group, on cylindrical sealant stubs (3.24 mm diameter x 3 mm height) for 12 groups (three etch conditions, two prophylactic methods, and two enamel surface type). The highest mean values of shear bond strength of 22.0 MPa was measured for H3PO4, and the lowest of 12.7 MPa for HNO3 (2.5%) without water wash. No significant differences (P < 0.05) were found between water rinse and air blast post-treatment groups after HNO3 conditioning. PMID:7567635

  3. 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.

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

    PubMed

    Hibino, Takashi; Kobayashi, Kazuyo; Nagao, Masahiro; Kawasaki, Shinji

    2015-01-20

    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.

  5. Traveling wave ion mobility mass spectrometry and ab initio calculations of phosphoric acid clusters.

    PubMed

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

    Positive and negative ion electrospray mass spectra obtained from 50 mM phosphoric acid solutions presented a large number of phosphoric acid clusters: [(H3PO4)n + zH](z+) or [(H3PO4)n - zH](z-), with n up to 200 and z up to 4 for positively charged clusters, and n up to 270 and z up to 7 for negatively charged cluster ions. Ion mobility experiments allowed very explicit separation of the different charge states. Because of the increased pressures involved in ion mobility experiments, dissociation to smaller clusters was observed both in the trap and transfer areas. Voltages along the ion path could be optimized so as to minimize this effect, which can be directly associated with the cleavage of hydrogen bonds. Having excluded the ion mobility times that resulted from dissociated ions, each cluster ion appeared at a single drift time. These drift times showed a linear progression with the number of phosphoric atoms for cluster ions of the same charge state. Cross section calculations were carried out with MOBCAL on DFT optimized geometries with different hydrogen locations and with three types of atomic charges. DFT geometry optimizations yielded roughly spherical structures. Our results for nitrogen gas interaction cross sections showed that values were dependent on the atomic charges definition used in the MOBCAL calculation. This pinpointed the necessity to define a clear theoretical framework before any comparative interpretations can be attempted with uncharacterized compounds.

  6. A fuel cell operating between room temperature and 250 °C based on a new phosphoric acid based composite electrolyte

    NASA Astrophysics Data System (ADS)

    Lan, Rong; Xu, Xiaoxiang; Tao, Shanwen; Irvine, John T. S.

    A phosphoric acid based composite material with core-shell microstructure has been developed to be used as a new electrolyte for fuel cells. A fuel cell based on this electrolyte can operate at room temperature indicating leaching of H 3PO 4 with liquid water is insignificant at room temperature. This will help to improve the thermal cyclability of phosphoric acid based electrolyte to make it easier for practical use. The conductivity of this H 3PO 4-based electrolyte is stable at 250 °C with addition of the hydrophilic inorganic compound BPO 4 forming a core-shell microstructure which makes it possible to run a PAFC at a temperature above 200 °C. The core-shell microstructure retains after the fuel cell measurements. A power density of 350 mW/cm 2 for a H 2/O 2 fuel cell has been achieved at 200 °C. The increase in operating temperature does not have significant benefit to the performance of a H 2/O 2 fuel cell. For the first time, a composite electrolyte material for phosphoric acid fuel cells which can operate in a wide range of temperature has been evaluated but certainly further investigation is required.

  7. 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).

  8. Granulated activated carbon modified with hydrophobic silica aerogel-potential composite materials for the removal of uranium from aqueous solutions.

    PubMed

    Coleman, Sabre J; Coronado, Paul R; Maxwell, Robert S; Reynolds, John G

    2003-05-15

    Aqueous solutions of 100 parts per billion (ppb) uranium at pH 7 were treated with granulated activated carbon (GAC) that had been modified with various formulations of hydrophobic aerogels. The composite materials were found to be superior in removing uranium from a stock solution compared to GAC alone evaluated by a modified ASTM D 3860-98 method for batch testing. The testing results were evaluated using a Freundlich adsorption model. The best performing material has parameters of n = 287 and Kf = 1169 compared to n = 1.00, and Kf = 20 for GAC alone. The composite materials were formed by mixing (CH3O)4Si with the hydrophobic sol-gel precursor, (CH3O)3SiCH2CH2CF3 and with specified modifiers, such as H3PO4, Ca(NO3)2, and (C2H5O)3SiCH2CH2P(O)(OC2H5)2, elation catalysts, and GAC in a supercritical reactor system. After gelation, supercritical extraction, and sieving, the composites were tested. Characterization by FTIR and 31P NMR indicate the formation of phosphate in the case of the H3PO4 and Ca(NO3)2 composites and phosphonic acid related compounds in the phosphonate composite. These composite materials have potential application in the clean up of groundwater at DOE and other facilities.

  9. 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.

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

    PubMed

    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. PMID:24522166

  11. Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats.

    PubMed

    Ishikawa, Kunio; Tram, Nguyen Xuan Thanh; Tsuru, Kanji; Toita, Riki

    2015-02-01

    Although porous calcite has attracted attention as bone substitutes, limited studies have been made so far. In the present study, porous calcite block was fabricated by introducing chopped nylon fiber as porogen. Ca(OH)2 powder containing 10 wt% chopped nylon fiber was compacted at 150 MPa, and sintered to burn out the fiber and to carbonate the Ca(OH)2 under stream of 1:2 O2-CO2. Sintering of Ca(OH)2 at 750 °C or lower temperature resulted in incomplete burning out of the fiber whereas sintering at 800 °C or higher temperature resulted in the formation of CaO due to the thermal decomposition of Ca(OH)2. However, sintering at 770 °C resulted in complete burning out of the fiber and complete carbonation of Ca(OH)2 to calcite without forming CaO. Macro- and micro-porosities of the porous calcite were approximately 23 and 16%, respectively. Diameter of the macropores was approximately 100 μm which is suitable for bone tissue penetration. Porous calcite block fabricated by this method exhibited good tissue response when implanted in the bone defect in femur of 12-weeks-old rat. Four weeks after implantation, bone bonded on the surface of calcite. Furthermore, bone tissue penetrated interior to the macropore at 8 weeks. These results demonstrated the good potential value of porous calcite as artificial bone substitutes.

  12. 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

  13. Fabrication of microporous calcite block from calcium hydroxide compact under carbon dioxide atmosphere at high temperature.

    PubMed

    Otsu, Akihiro; Tsuru, Kanji; Maruta, Michito; Munar, Melvin L; Matsuya, Shigeki; Ishikawa, Kunio

    2012-01-01

    Effects of carbonation temperature and compacting pressure on basic properties of calcite block were studied using Ca(OH)2 compact made with 0.2-2.0 MPa and their carbonation at 200-800ºC for 1 h. Microporous calcite was obtained only when carbonated at 600ºC using Ca(OH)2 compact made with 0.2 MPa even though thermogravimetry analysis showed that calcite powder was stable up to 920ºC under CO2 atmosphere. CaO formed by carbonation at 700ºC and 800ºC is thought to be caused by the limited CO2 diffusion interior to the Ca(OH)2 compact. Also, unreacted Ca(OH)2 was found for Ca(OH)2 compact prepared with 0.5 MPa or higher pressure even when carbonated at 600ºC. As a result of high temperature carbonation, crystallite size of the calcite, 58.0 nm, was significantly larger when compared to that of calcite prepared at room temperature, 35.5 nm. Porosity and diametral tensile strength of the microporous calcite were 39.5% and 6.4 MPa. PMID:22864212

  14. Effect of calcium hydroxide on proinflammatory cytokines and neuropeptides.

    PubMed

    Khan, Asma A; Sun, Xiaoling; Hargreaves, Kenneth M

    2008-11-01

    Calcium hydroxide, a widely used intracanal medicament, is known to exert an antimicrobial effect and to degrade bacterial-derived lipopolysaccharides. However, little is known about the effect of Ca(OH)(2) on endogenous inflammatory mediators such as interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), and calcitonin gene-related peptide (CGRP). This is an important gap in knowledge because these inflammatory mediators play an important role in mediating the pathogenesis of periradicular periodontitis. We tested the hypothesis that Ca(OH)(2) denatures IL-1 alpha, TNF-alpha, and CGRP. Human IL-1 alpha (0.125 ng/mL), TNF-alpha (0.2 ng/mL), and CGRP (0.25 ng/mL) were incubated with Ca(OH)(2) (0.035 mg/mL) for 1-7 days. At the end of the incubation period, the pH of the samples was neutralized, and the concentrations of the mediators were measured by immunoassays. Data were analyzed with one-way analysis of variance and Bonferroni multiple comparison tests. The results indicate that Ca(OH)(2) denatures IL-1 alpha, TNF-alpha, and CGRP by 50%-100% during the testing periods (P < .001). We concluded that denaturation of these proinflammatory mediators is a potential mechanism by which Ca(OH)(2) contributes to the resolution of periradicular periodontitis. PMID:18928847

  15. Influence of calcium hydroxide on the fate of perfluorooctanesulfonate under thermal conditions.

    PubMed

    Wang, Fei; Lu, Xingwen; Shih, Kaimin; Liu, Chengshuai

    2011-09-15

    To explore the potential fate and transport of perfluorochemicals in the thermal treatment of sludge, perfluorooctanesulfonate (PFOS), a perfluorochemical species commonly dominant in wastewater sludge, was mixed with hydrated lime (Ca(OH)(2)) to quantitatively observe their interaction under different temperatures. The phase compositions of the mixtures after the reactions were qualitatively identified and quantitatively determined using X-ray diffraction technique. The results of the thermogravimetry and differential scanning calorimetry analyses indicate that PFOS gasified directly during the thermal treatment process when the temperature was increased to around 425 °C. However, the formation of CaF(2) at 350 °C suggests that the presence of Ca(OH)(2) in the mixture can lead to the decomposition of PFOS at 350 °C, which is lower than the decomposition temperature of PFOS alone (425 °C). The increase of temperature promoted a solid state reaction between PFOS and Ca(OH)(2), and also enhanced the interaction between the gaseous products of PFOS and CaO (or Ca(OH)(2)). The preferred Ca/F molar ratio to achieve fluorine stabilization by Ca(OH)(2) was above 1:1 in the experiment involving 400 °C and 600 °C treatment. It also showed that equilibrium efficiency is achieved within 5 min at 400 °C and within 1 min above 600°C. PMID:21719193

  16. Long term effect of alkali types on waste activated sludge hydrolytic acidification and microbial community at low temperature.

    PubMed

    Jin, Baodan; Wang, Shuying; Xing, Liqun; Li, Baikun; Peng, Yongzhen

    2016-01-01

    The effect of four alkali reagents (NaOH, KOH, Ca(OH)2, mixed alkali) on waste activated sludge (WAS) hydrolytic acidification and microbial community was studied in semi-continuous fermentation systems at low temperature (15°C) over long term operational time (65day). The results showed that protein and polysaccharide of NaOH (124.26, 11.92) was similar to that of KOH (109.53, 11.30), both were higher than Ca(OH)2 (70.66, 3.74) and mixed alkali (90.66, 8.71). The short chain fatty acids (SCFAs) of NaOH (231.62) was higher than KOH (220.62mg chemical oxygen demand (COD)/g VSS). Although Ca(OH)2 system had strong acidification capacity, the shortage of SCFAs occurred due to the low activity of hydrolase. Illumina MiSeq sequencing revealed that Tissierella and Erysipelothrix were enriched in the NaOH and Ca(OH)2 systems, where Peptostreptococcaceae incertae_sedis was enriched in the NaOH and KOH systems, less Anaerolinea was involved in Ca(OH)2 condition. PMID:26546788

  17. Orosensory responsiveness to and preference for hydroxide-containing salts in mice.

    PubMed

    St John, Steven J; Boughter, John D

    2009-07-01

    Historically, taste researchers have considered the possibility that the gustatory system detects basic compounds, such as those containing the hydroxide ion, but evidence for an "alkaline taste" has not been strong. We found that, in 48 h, 2-bottle preference tests, C3HeB/FeJ (C3) mice showed a preference for Ca(OH)(2), whereas SWR/J (SW) mice showed avoidance. Strain differences were also apparent to NaOH but not CaCl(2). Follow-up studies showed that the strain difference for Ca(OH)(2) was stable over time (Experiment 2) but that C3 and SW mice did not differ in their responses to Ca(OH)(2) or NaOH in brief-access tests, where both mice avoided high concentrations of these compounds (Experiment 3). In order to assess the perceived quality of Ca(OH)(2), mice were tested in 2 taste aversion generalization experiments (Experiments 4 and 5). Aversions to Ca(OH)(2) generalized to NaOH but not CaCl(2) in both strains, suggesting that the generalization was based on the hydroxide ion. Both strains also generalized aversions to quinine, suggesting the possibility that the hydroxide ion has a bitter taste quality to these mice, despite the preference shown by C3 mice to middle concentrations in long-term tests.

  18. Effects of olive mill wastewater physico-chemical treatments on polyphenol abatement and Italian ryegrass (Lolium multiflorum Lam.) germinability.

    PubMed

    Barbera, A C; Maucieri, C; Ioppolo, A; Milani, M; Cavallaro, V

    2014-04-01

    Direct spreading on agricultural lands may represent an environmentally friendly disposal method and a possible use of water and nutrients from olive mill wastewaters (OMWs). However, the agronomic use of OMWs is limited, among others by polyphenols, which exert phytotoxic effects. Activated charcoal (AC) has been recognized as a very effective agent for polyphenol abatement, as it enables an irreversible process of phenol adsorption. Addition of calcium hydroxide (Ca(OH)2) has also been described as a cheap and effective method in polyphenols abatement. However, the effects of Ca(OH)2 addition to OMW on seed germination are unclear. In this paper, the effects of AC and/or Ca(OH)2 on OMW polyphenols abatement, and Lolium multiflorum seed germination have been investigated. The highest polyphenols removal, approximately 95%, was observed when 80 g L(-1) of AC was added to OMWs (the maximum dose in this investigation). The addition of Ca(OH)2 not only improved the effectiveness of the AC treatment but also resulted in a significant rise in Lolium seed germination at the highest AC doses (60 and 80 g L(-1)). Considering the high salinity (7300 μS cm(-1)) of these wastewaters, low quantities of Ca(OH)2 may also exert a protective effect on soil structure counteracting the sodium-induced dispersion through the binding action of calcium cation on clays and organic matter.

  19. 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.

  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. 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.

  2. 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

  3. 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.

  4. Using Apatite to Model Chlorine Contents of High SiO2 Magmas: An Enhanced Methodological Approach

    NASA Astrophysics Data System (ADS)

    Flesch, R.; Webster, J. D.; Nadeau, P. A.

    2015-12-01

    Hydrothermal experiments were conducted on high-silica (73-75 wt% SiO2), fluid-saturated melts at 844-862°C and ca. 50 MPa using crushed glass of the Los Posos rhyolite. Water and salts including NaCl, KCl, Ca(OH)2, and CaHPO4 and HCl were added proportionally to the experiments to restrict the variability of the aluminosity of the melt. The Durango apatite, which contains 3.53 wt% F and 0.41% Cl, was added as "seeds"<5µm in diameter to stimulate apatite growth during the experiments. Samples were loaded into gold capsules and run in cold-seal pressure vessels for durations of 286-1008 hours. Temperature was cycled at ±20˚C to promote apatite crystallization. Electron microprobe analyses of run-product glasses and embedded apatite grains support calculation of a range of partition coefficients ( = wt% Cl in apatite/wt% Cl in melt) of 4.7 to 15.9. The mole fraction of Cl in experimental apatites, or XCl, ranges from 0.19 to 0.56, while XF ranges from 0.08 to 0.63. The computed values for XOH range from 0.24 to 0.38. We find that normalizing XCl to XOH of apatites dramatically improves the precision when using apatite compositions to model Cl contents of melts. We compare our Los Posos rhyolite experiments with published data on 50 MPa rhyodacite experiments and find that Cl partitioning is significantly different in each system. Given the importance of chlorine in fluid equilibria, ore transport, and magma evolution, applications of apatite as a proxy for Cl contents in melts are unbounded. It is found that in order to accurately use the volatile composition of natural and synthetic apatites to calculate the volatile composition of melts in felsic systems, several chemical factors, including wt% SiO2 and the aluminosity/alkalinity of melts, should be incorporated as parameters to enhance relevant modeling. This allows geochemists to place better constraints on processes associated with crystallizing Cl-bearing magmatic systems.

  5. Optimization of the alkaline pretreatment of rice straw for enhanced methane yield.

    PubMed

    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 (R(2)) 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

  6. 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

  7. An in vitro evaluation of the cytotoxicity of various endodontic irrigants on human gingival fibroblasts.

    PubMed

    Barnhart, Brian D; Chuang, Augustine; Lucca, Jurandir J Dalle; Roberts, Steven; Liewehr, Frederick; Joyce, Anthony P

    2005-08-01

    The purpose of this study was to measure the cytotoxicity of six endodontic irrigants on cultured gingival fibroblasts using the CyQuant assay. Human gingival fibroblasts were grown in Dulbecco's Modified Eagle Medium (DMEM) containing 10% fetal bovine serum at 37 degrees C and 5% CO(2). At confluence, cells were split, plated in 96-well plates and incubated for 24-h to allow attachment. The following irrigants were tested at various concentrations: Sodium hypochlorite (NaOCl); iodine potassium-iodide (IKI); Betadine scrub (BS); calcium hydroxide [Ca(OH)2]; chlorine dioxide (SCD) and DMEM (positive control). Experimental groups were compared by the logarithmic difference between the clinical and LD50 concentrations of a particular irrigant. The results showed that IKI and Ca(OH)2 were significantly less cytotoxic than SCD, NaOCl, and BS. In conclusion, IKI and Ca(OH)2 are well tolerated by human gingival fibroblasts.

  8. 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.

  9. A histologic assessment of a HYBENX® oral tissue decontaminant in vital pulp therapy in dogs.

    PubMed

    Rohrer, M D; Prasad, H S; Savord, E G

    2016-01-01

    The aim of this study was to assess HYBENX® Oral Tissue Decontaminant (HOTD) in treating vital pulp exposure in a canine model. The use of HOTD solution was compared to an accepted and standard regimen for vital pulp exposure, an application of a commercial calcium hydroxide product (Ca(OH)2). Both control and experimental treatments were followed by restoration with a commercial zinc oxide and eugenol obtundant intermediate restorative material and thermal insulator (ZOE). At 7 days there was 100% pulp vitality with HOTD and 50% with Ca(OH)2. New dentin formation was seen in 62.5% of the HOTD treated pulps and none of the Ca(OH)2 treatment group. The vital pulp exposures at day 21 post treatment with HOTD also showed significant improvement over Ca(OH)2 in the presence of odontoblasts, new dentin formation and pulp survivability. The presence of odontoblasts and new dentin was noted in 71% of the HOTD cases versus 50% of the survivable Ca(OH)2 cases. Furthermore, 100% of HOTD cases had vital pulps versus 62.5% of Ca(OH)2 cases. The 60-day specimens of both experimental and control techniques exhibited histologically similar appearances and were similar in outcomes. HOTD treatment at day 7 showed a significant positive difference, both in the formation of new dentin and tooth vitality. HOTD proved better for the post 21-day specimens and equivalent for the 60-day pulp specimens with no evidence of untoward tissue reactions or results. PMID:27469568

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Micelle to trapping solution stacking in micellar electrokinetic chromatography.

    PubMed

    Liu, Lihong; Deng, Xinxian; Chen, Xingguo

    2010-01-01

    An analytical strategy micelle to trapping solution stacking (MSS) was developed in acidic buffer in micellar electrokinetic chromatography (MEKC). The stacking mechanism is based on the transport, release, capturing of molecules bound to micelle carriers that are made to collapse into trapping solution (TS) to serve as the medium to contain and stacking the analytes. Tetrandrine and fangchinoline were selected as model mixture using sodium dodecyl sulfate (SDS) micelles as carrier to demonstrate this stacking method. The experiments by MSS-MEKC were carried out and further compared with those by normal MEKC. The results reveal that 113-123-fold improvements in the detection sensitivity was obtained for the analytes, and separation and determination of tetrandrine and fangchinoline in Stephaniae tetrandrae S. Moore and Fengtongan capsules were finished under optimum conditions using the sample matrix containing 8.0mM SDS and TS containing 50mM H(3)PO(4)-55% (v/v) ethanol. PMID:19945115

  16. Anodically Electrodeposited Iridium Oxide Films (AEIROF) from Alkaline Solutions for Electrochromic Display Devices

    NASA Astrophysics Data System (ADS)

    Yamanaka, Kazusuke

    1989-04-01

    Anodically electrodeposited iridium oxide films from alkaline solutions were investigated for application to electrochromic devices. Micro-crystalline (diameter: 15Å) films obtained by the electrolysis of aqueous alkaline solutions containing iridium chloride, oxalic acid and potassium carbonate showed good electrochromic reaction reversibility. The coloration efficiency of the films was about one third that of typical evaporated tungsten oxide films, and the response rate measured by the amount of injected charge was about double. The cycle lives of the cells, composed of electrodeposited films, 1M H3PO4-NaOH (pH{=}3˜ 5), and an activated carbon cloth, were more than 8× 106 with a 0.6 V, 1 Hz continuous square wave.

  17. Preparation of granular activated carbons from yellow mombin fruit stones for CO2 adsorption.

    PubMed

    Fiuza, Raildo Alves; Medeiros de Jesus Neto, Raimundo; Correia, Laise Bacelar; Carvalho Andrade, Heloysa Martins

    2015-09-15

    Stones of yellow mombin, a native fruit of the tropical America and West Indies, were used as starting materials to produce activated carbons, subsequently used as adsorbent for CO2 capture. The carbonaceous materials were either chemically activated with HNO3, H3PO4 and KOH or physically activated with CO2. The carbon samples were characterized by SEM, EDX, TG/DTA, Raman spectroscopy, physical adsorption for textural analysis and by acid-base titrations. The CO2 adsorption capacity and adsorption cycles were investigated by TG. The results indicate that the capacity of CO2 adsorption may be maximized on highly basic surfaces of micropores smaller than 1 nm. The KOH activated carbon showed high and stable capacity of CO2 adsorption after 10 cycles.

  18. 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.

  19. 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.

  20. Anodic titanium oxide as immobilized photocatalyst in UV or visible light devices.

    PubMed

    Diamanti, M V; Ormellese, M; Marin, E; Lanzutti, A; Mele, A; Pedeferri, M P

    2011-02-28

    Titanium anodizing can be a powerful technique to generate photoactive oxides, strongly adherent to the metallic substrate, and to modify their chemical composition by inducing doping effects. This work investigates the photocatalytic behavior of differently obtained anodic TiO(2) films under UV and visible light irradiation, so as to define the best treatment for wastewaters purifiers. Anodizing was performed in H(3)PO(4) and H(2)SO(4) mixtures or in fluoride containing electrolytes. Morphology, elemental composition and crystal structure of the anodic films were characterized by XDR, GDOES and SEM. When amorphous oxides were obtained, an annealing treatment was used to promote the formation of anatase crystals. Annealing was also performed in nitrogen atmosphere to induce nitrogen doping. The photocatalytic efficiency of anatase-enriched TiO(2) was investigated in rhodamine B photodegradation. Doping was induced not only by annealing but also directly by anodizing, and generated photoactivity in both the UV and Vis components of light.

  1. Redetermination of AgPO3

    PubMed Central

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  2. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-02-09

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

  3. Automated procedure for determination of ammonia in concrete with headspace single-drop micro-extraction by stepwise injection spectrophotometric analysis.

    PubMed

    Timofeeva, Irina; Khubaibullin, Ilnur; Kamencev, Mihail; Moskvin, Aleksey; Bulatov, Andrey

    2015-02-01

    A novel automatic stepwise injection headspace single-drop micro-extraction system is proposed as a versatile approach for automated determination of volatile compounds. The system application is demonstrated for ammonia determination in concrete samples. An ammonia gas was produced from ammonium ions and extracted on-line into 5 μL 0.1M H3PO4 to eliminate the interference effect of concrete species on the ammonia stepwise injection spectrophotometric determination. The linear range was 0.1-1 mg kg(-1) with LOD 30 µg kg(-1). The sample throughput was 4 h(-1). This system has been successfully applied for the determination of ammonia in concretes.

  4. Corn stalks char from fast pyrolysis as precursor material for preparation of activated carbon in fluidized bed reactor.

    PubMed

    Wang, Zhiqi; Wu, Jingli; He, Tao; Wu, Jinhu

    2014-09-01

    Corn stalks char from fast pyrolysis was activated by physical and chemical activation process in a fluidized bed reactor. The structure and morphology of the carbons were characterized by N2 adsorption and SEM. Effects of activation time and activation agents on the structure of activation carbon were investigated. The physically activated carbons with CO2 have BET specific surface area up to 880 m(2)/g, and exhibit microporous structure. The chemically activated carbons with H3PO4 have BET specific surface area up to 600 m(2)/g, and exhibit mesoporous structure. The surface morphology shows that physically activated carbons exhibit fibrous like structure in nature with long ridges, resembling parallel lines. Whereas chemically activated carbons have cross-interconnected smooth open pores without the fibrous like structure.

  5. 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.

  6. 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.

  7. Corrosion characteristics of anodized Ti-(10-40wt%)Hf alloys for metallic biomaterials use.

    PubMed

    Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A

    2011-01-01

    The effect of anodizing on corrosion resistance of Ti-xHf alloys has been investigated. Ti-xHf alloys were prepared and anodized at 120, 170 and 220 V in 1 M H(3)PO(4) solution, and crystallized at 300 and 500°C. Corrosion experiments were carried out using a potentiostat in 0.15 M NaCl solution at 36.5 ± 1°C. The Ti-xHf alloys exhibited the α' and anatase phases. The pore size on the anodized surface increases as the applied voltage is increased, whereas the pore size decreases as the Hf content is increased. The anodized Ti-xHf alloys exhibited better corrosion resistance than non-anodized Ti-xHf alloys.

  8. Comparative study of mechanical, hydrothermal, chemical and enzymatic treatments of digested biofibers to improve biogas production.

    PubMed

    Bruni, Emiliano; Jensen, Anders Peter; Angelidaki, Irini

    2010-11-01

    Organic waste such as manure is an important resource for biogas production. The biodegradability of manures is however limited because of the recalcitrant nature of the biofibers it contains. To increase the biogas potential of the biofibers in digested manure, we investigated physical treatment (milling), chemical treatment (CaO), biological treatment (enzymatic and partial aerobic microbial conversion), steam treatment with catalyst (H(3)PO(4) or NaOH) and combination of biological and steam treatments (biofibers steam-treated with catalyst were treated with laccase enzyme). We obtained the highest methane yield increase through the chemical treatment that resulted in 66% higher methane production compared to untreated biofibers. The combination of steam treatment with NaOH and subsequent enzymatic treatment increased the methane yield by 34%. To choose the optimal treatment, the energy requirements relative to the energy gain as extra biogas production have to be taken into account, as well as the costs of chemicals or enzymes.

  9. Effects of Kraft lignin on hydrolysis/dehydration of sugars, cellulosic and lignocellulosic biomass under hot compressed water.

    PubMed

    Daorattanachai, Pornlada; Viriya-empikul, Nawin; Laosiripojana, Navadol; Faungnawakij, Kajornsak

    2013-09-01

    The effect of Kraft lignin presenting on the hydrolysis and dehydration of C5 and C6 sugars, cellulose, hemicelluloses and biomass under hot compressed water (HCW) in the presence of H3PO4 catalyst was intensively studied. The lignin strongly inhibited the acid hydrolysis of cellulose and hemicellulose to glucose and xylose, respectively. Interestingly, the admixed lignin markedly promoted the isomerization of glucose to fructose, and dehydration of fructose (except at the low catalyst loading), resulting in high 5-hydroxymethylfurfural yields. Nonetheless, lignin inhibited the hydrolysis of xylan to xylose and dehydration of xylose to furfural. Moreover, the acidity of the system significantly affects the hydrolysis/dehydration of biomass. It was revealed that the presence of lignin strongly interfered the yields of sugars and furans produced from raw corncob, while the delignified corncob provided significant improvement of product yields, confirming the observed role of lignin in the biomass conversion system via sugar platforms. PMID:23907066

  10. 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

  11. 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.

  12. Ligand field theory and the origin of life as an emergent feature of the periodic table of elements.

    PubMed

    Morowitz, Harold J; Srinivasan, Vijayasarathy; Smith, Eric

    2010-08-01

    The assumption that all biological catalysts are either proteins or ribozymes leads to an outstanding enigma of biogenesis-how to determine the synthetic pathways to the monomers for the efficient formation of catalytic macromolecules in the absence of any such macromolecules. The last 60 years have witnessed chemists developing an understanding of organocatalysis and ligand field theory, both of which give demonstrable low-molecular-weight catalysts. We assume that transition-metal-ligand complexes are likely to have occurred in the deep ocean trenches by the combination of naturally occurring oceanic metals and ligands synthesized from the emergent CO(2), H(2), NH(3), H(2)S, and H(3)PO(4). We are now in a position to investigate experimentally the metal-ligand complexes, their catalytic function, and the reaction networks that could have played a role in the development of metabolism and life itself.

  13. The growth and Raman scattering studies of TGSP crystal as the IR room temperature infrared detector

    NASA Astrophysics Data System (ADS)

    Malekfar, R.; Abbasi, B.

    2005-09-01

    The partial substitution of sulphate (SO42-) by phosphate (PO43-) in triglycine sulfate (TGS) single crystal can improve the properties of the TGS family crystal as room temperature infrared (IR) detector. Phosphoric acid (H3PO4)-doped triglycine sulfate (TGSP) single crystal has strong pyroelectric properties due to its high pyroelectric coefficient and reasonably low dielectric constant. This family of single crystals can grow easily and rapidly and are reasonably good uniform detectors in the electromagnetic region from UV to IR at room temperature and without using cryogenic cooling. TGSP single crystals were grown by saturated solution method. In order to investigate the detection sensitivity of the TGSP crystal, single crystals with different dopant concentration of phosphate (PO43-) ion were grown. A rather complete back-scattering Raman scattering spectra and hysteresis loops of the grown crystals were recorded and compared with each other. The Raman spectra and their assignments only will be reported here.

  14. 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

  15. [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

  16. Electrochemical behavior and voltammetric determination of vanillin based on an acetylene black paste electrode modified with graphene-polyvinylpyrrolidone composite film.

    PubMed

    Deng, Peihong; Xu, Zhifeng; Zeng, Rongying; Ding, Chunxia

    2015-08-01

    The graphene-polyvinylpyrrolidone composite film modified acetylene black paste electrode (GR-PVP/ABPE) was fabricated and used to determine vanillin. In 0.1M H3PO4 solution, the oxidation peak current of vanillin increased significantly at GR-PVP/ABPE compared with bare ABPE, PVP/ABPE and GR/ABPE. The oxidation mechanism was discussed. The experimental conditions that exert influence on the voltammetric determination of vanillin, such as supporting electrolytes, pH values, accumulation potential and accumulation time, were optimized. Besides, the interference, repeatability, reproducibility and stability measurements were also evaluated. Under the optimal experimental conditions, the oxidation peak current was proportional to vanillin concentration in the range of 0.02-2.0 μM, 2.0-40 μM and 40-100 μM. The detection limit was 10nM. This sensor was used successfully for vanillin determination in various food samples.

  17. 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.

  18. 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.

  19. A numerical model for CO effect evaluation in HT-PEMFCs: Part 2 - Application to different membranes

    NASA Astrophysics Data System (ADS)

    Cozzolino, R.; Chiappini, D.; Tribioli, L.

    2016-06-01

    In this paper, a self-made numerical model of a high temperature polymer electrolyte membrane fuel cell is presented. In particular, we focus on the impact of CO poisoning on fuel cell performance and its influence on electrochemical modelling. More specifically, the aim of this work is to demonstrate the effectiveness of our zero-dimensional electrochemical model of HT-PEMFCs, by comparing numerical and experimental results, obtained from two different commercial membranes electrode assemblies: the first one is based on polybenzimidazole (PBI) doped with phosphoric acid, while the second one uses a PBI electrolyte with aromatic polyether polymers/copolymers bearing pyridine units, always doped with H3PO4. The analysis has been carried out considering both the effect of CO poisoning and operating temperature for the two membranes above mentioned.

  20. All-solid-state micro-supercapacitors based on inkjet printed graphene electrodes

    NASA Astrophysics Data System (ADS)

    Li, Jiantong; Mishukova, Viktoriia; Ã-stling, Mikael

    2016-09-01

    The all-solid-state graphene-based in-plane micro-supercapacitors are fabricated simply through reliable inkjet printing of pristine graphene in interdigitated structure on silicon wafers to serve as both electrodes and current collectors, and a following drop casting of polymer electrolytes (polyvinyl alcohol/H3PO4). Benefiting from the printing processing, an attractive porous electrode microstructure with a large number of vertically orientated graphene flakes is observed. The devices exhibit commendable areal capacitance over 0.1 mF/cm2 and a long cycle life of over 1000 times. The simple and scalable fabrication technique for efficient micro-supercapacitors is promising for on-chip energy storage applications in emerging electronics.

  1. Effects of ultrasonic fields in the phosphoric acid process

    NASA Technical Reports Server (NTRS)

    Kowalska, E.; Mizera, J.; Jakobiec, H.

    1974-01-01

    A process of apatite decomposition with sulfuric acid was studied under the influence of ultrasound in the phosphoric acid production process. The studies were carried out with and without ultrasonic fields in the reaction mixture, which resembled the mixing ratio used in technical production processes. Ultrasound with a frequency of 20 kHz and an intensity of 1 W/sq cm was used in the studies. A very favorable ultrasonic effect upon the degree of apatite decomposition was observed. The ultrasonic field affects the shape of byproduct gypsum crystals. In the H3PO4 production process without ultrasound, the byproduct gypsum crystallizes as long, thin needles which cause problems in filtration. In the trials involving the application of wound, gypsum crystallized in the form of small platelets possessing a favorable ratio of length to width.

  2. 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

  3. Crystallization of calcium sulfate dihydrate in the presence of some metal ions

    NASA Astrophysics Data System (ADS)

    Hamdona, Samia K.; Al Hadad, Umaima A.

    2007-02-01

    Crystallization of calcium sulfate dihydrate (CaSO 4·2H 2O gypsum) in sodium chloride solutions in the presence of some metal ions, and over a range of relative super-saturation has been studied. The addition of metal ions, even at relatively low concentration (10 -6 mol l -1), markedly retard the rate of crystallization of gypsum. Retardation effect was enhanced with increase in the additives contents. Moreover, the effect was enhanced as the relative super-saturation decreases. Influence of mixed additives on the rate of crystallization (Cd 2++Arg, Cd 2++H 3PO 4 and Cd 2++PAA) has also been studied. Direct adsorption experiments of these metal ions on the surface of gypsum crystals have been made for comparison.

  4. Fabrication of highly ordered nanoporous alumina films by stable high-field anodization

    NASA Astrophysics Data System (ADS)

    Li, Yanbo; Zheng, Maojun; Ma, Li; Shen, Wenzhong

    2006-10-01

    Stable high-field anodization (1500-4000 A m-2) for the fabrication of highly ordered porous anodic alumina films has been realized in a H3PO4-H2O-C2H5OH system. By maintaining the self-ordering voltage and adjusting the anodizing current density, high-quality self-ordered alumina films with a controllable inter-pore distance over a large range are achieved. The high anodizing current densities lead to high-speed film growth (4-10 µm min-1). The inter-pore distance is not solely dependent on the anodizing voltage, but is also influenced by the anodizing current density. This approach is simple and cost-effective, and is of great value for applications in diverse areas of nanotechnology.

  5. Dyes extracted from Trigonella seeds as photosensitizers for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Batniji, Amal; Abdel-Latif, Monzir S.; El-Agez, Taher M.; Taya, Sofyan A.; Ghamri, Hatem

    2016-06-01

    In this paper, the extract of Trigonella seeds was used as sensitizer for dye-sensitized solar cells (DSSCs). The natural dye was extracted from the seeds using water and alcohol as solvents for the raw material. The UV-Vis absorption spectra of Trigonella extract solution and dye adsorbed on TiO2 film were measured. DSSCs sensitized by Trigonella extracted using water as a solvent exhibited better performance with efficiency of 0.215 %. The performance of the fabricated DSSCs was attempted to enhance by acid treatment of the FTO substrates with HNO3, H3PO4, and H2SO4. Electrochemical impedance spectroscopy of the fabricated cells was also carried out.

  6. 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.

  7. Strongly reduced Si surface recombination by charge injection during etching in diluted HF/HNO3.

    PubMed

    Greil, Stefanie M; Schöpke, Andreas; Rappich, Jörg

    2012-08-27

    Herein, we investigate the behaviour of the surface recombination of light-induced charge carriers during the etching of Si in alkaline (KOH) and acidic etching solutions of HF/HNO(3)/CH(3)COOH (HNA) or HF/HNO(3)/H(3)PO(4) (HNP) at different concentration ratios of HF and HNO(3) by means of photoluminescence (PL) measurements. The surface recombination velocity is strongly reduced during the first stages of etching in HF/HNO(3)-containing solutions pointing to a interface well passivated by the etching process, where a positive surface charge is induced by hole injection from NO-related surface species into the Si near-surface region (back surface field effect). This injected charge leads to a change in band bending by about 150 mV that repulses the light-induced charge carriers from the surface and therefore enhances the photoluminescence intensity, since non-radiative surface recombination is reduced.

  8. The effect of phosphoric acid concentration on the synthesis of nano-whiskers of calcium metaphosphate by chemical precipitation Method

    NASA Astrophysics Data System (ADS)

    Yao, Nengjian; Zhang, Yin; Kong, Deshuang; Zhu, Jianping; Tao, Yaqiu; Qiu, Tai

    2011-10-01

    Calcium metaphosphate (CMP) nano-whiskers were produced by a chemical precipitation method. In order to produce nano-powders, CMP was prepared by the mixing of two precursors, calcium oxide (CaO) and phosphate acid (H3PO4). Sparingly soluble chemicals, the Ca/P ratio of the mixture was set to be 0.50 to produce stoichiometric CMP, were chemical agitated in phosphate acid solution. At least 3 hours of pre-hydrolysis of phosphorus precursor were required to obtain CMP phase. The CMP powders were dried in a drying oven at 60 °C for 7 days and then followed by a heat treatment at 390 °C for 8hours. The obtained powder was analyzed using XRD, XRF, FT-IR, SEM, TG-DTA, Zeta Potential Meter, Specific Surface Area, and Particle Size Analyzer. The results showed that obtained CMP nano-whiskers have a significantly powder characteristics.

  9. 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.

  10. High performance etchant for thinning p(+)-InP and its application to p(+)n InP solar cell fabrication

    NASA Technical Reports Server (NTRS)

    Faur, Maria; Faur, Mircea; Bailey, Sheila; Brinker, David; Goradia, Manju; Weinberg, Irving; Fatemi, Navid

    1991-01-01

    An etchant, namely (o-H3PO4)u: (HNO3)v: (H2O2)t: (H2O)1-(u+v+t) is developed for thinning, after contacting, the p(+) emitter layer of p(+)n InP structures made by thermal diffusion. Varying u, v, and t, reproducible etch rates of 5 to 110 nm/min are obtained. After thinning the 0.6- to 2.5-micron thick p(+) InP layer down to 60-250 nm, specular surfaces are obtained at up to 80 nm/min etch rate. Due to its intrinsic qualities the resisual P-rich oxide after thinning the emitter layer provides surface passivation of p(+) InP surfaces and can also serve as a first-layer AR coating.

  11. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure. PMID:21522230

  12. The contraction of granules of nanoporous super-cross-linked polystyrene sorbents as a result of the exclusion of large-sized mineral electrolyte ions from the polymer phase

    NASA Astrophysics Data System (ADS)

    Pastukhov, A. V.; Davankov, V. A.; Tsyurupa, M. P.; Blinnikova, Z. K.; Kavalerskaya, N. E.

    2009-03-01

    The deformation of neutral super-cross-linked polystyrene sorbents and ionites based on styrene-divinylbenzene gel-type copolymers brought in contact with concentrated solutions of HCl, H3PO4, NaOH, NH4Cl, (NH4)2SO4, and LiCl electrolytes was studied by dilatometry for separate spherical granules. Considerable contraction of super-cross-linked polystyrene matrices swollen in water was observed in concentrated solutions containing large-sized lithium, sulfate, and phosphate ions. Volume compressive strain correlated with the size of excluded hydrated ions. The contraction effect was caused by the difference in the osmotic pressure of water in thin pores and water in concentrated solutions filling large pores. The exclusion effect ignored earlier should also influence the degree of ion exchange and volume deformation of standard ion-exchange resins brought in contact with solutions of various electrolytes.

  13. 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.

  14. 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.

  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. 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...

  17. 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...

  18. 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...

  19. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    NASA Astrophysics Data System (ADS)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  20. 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…

  1. Effect of treating sugarcane bagasse with urea and calcium hydroxide on feed intake, digestibility, and rumen fermentation in beef cattle.

    PubMed

    Gunun, Nirawan; Wanapat, Metha; Gunun, Pongsatorn; Cherdthong, Anusorn; Khejornsart, Pichad; Kang, Sungchhang

    2016-08-01

    Four beef cattle with initial body weight of 283 ± 14 kg were randomly allocated according to a 4 × 4 Latin square design to study on the effect of feeding sugarcane bagasse (SB) treated with urea and/or calcium hydroxide (Ca(OH)2) on feed intake, digestibility, and rumen fermentation. The treatments were as follows: rice straw (RS), untreated SB (SB), 4 % urea-treated SB (SBU), and 2 % urea + 2 % Ca(OH)2-treated SB (SBUC), respectively. The results revealed that cattle fed with SBU and SBUC had higher feed intake and apparent digestibility. Ammonia nitrogen and blood urea nitrogen were increased in cattle fed with SB as roughage source (P < 0.05). Feeding SBU and SBUC to cattle resulted in higher propionic acid and lower acetic acid, acetic to propionic ratio, and methane production (P < 0.05). Moreover, the number of fungi was increased in SBU- and SBUC-fed groups while protozoa population was unchanged. This study concluded that the nutritive value of SB was improved by urea and/or Ca(OH)2 treatment, and feeding treated SB could increase feed intake, digestibility, and rumen fermentation. This study suggested that SB treated with 2 % urea + 2 % Ca(OH)2 could be used as an alternative roughage source for ruminant feeding.

  2. 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...

  3. 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...

  4. 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 ...

  5. 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 ...

  6. 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...

  7. Effect of treating sugarcane bagasse with urea and calcium hydroxide on feed intake, digestibility, and rumen fermentation in beef cattle.

    PubMed

    Gunun, Nirawan; Wanapat, Metha; Gunun, Pongsatorn; Cherdthong, Anusorn; Khejornsart, Pichad; Kang, Sungchhang

    2016-08-01

    Four beef cattle with initial body weight of 283 ± 14 kg were randomly allocated according to a 4 × 4 Latin square design to study on the effect of feeding sugarcane bagasse (SB) treated with urea and/or calcium hydroxide (Ca(OH)2) on feed intake, digestibility, and rumen fermentation. The treatments were as follows: rice straw (RS), untreated SB (SB), 4 % urea-treated SB (SBU), and 2 % urea + 2 % Ca(OH)2-treated SB (SBUC), respectively. The results revealed that cattle fed with SBU and SBUC had higher feed intake and apparent digestibility. Ammonia nitrogen and blood urea nitrogen were increased in cattle fed with SB as roughage source (P < 0.05). Feeding SBU and SBUC to cattle resulted in higher propionic acid and lower acetic acid, acetic to propionic ratio, and methane production (P < 0.05). Moreover, the number of fungi was increased in SBU- and SBUC-fed groups while protozoa population was unchanged. This study concluded that the nutritive value of SB was improved by urea and/or Ca(OH)2 treatment, and feeding treated SB could increase feed intake, digestibility, and rumen fermentation. This study suggested that SB treated with 2 % urea + 2 % Ca(OH)2 could be used as an alternative roughage source for ruminant feeding. PMID:27139254

  8. 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...

  9. 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...

  10. 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.

  11. 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.

  12. 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

  13. Effect of anodization and alkali-heat treatment on the bioactivity of titanium implant material (an in vitro study)

    PubMed Central

    Abdelrahim, Ramy A.; Badr, Nadia A.; Baroudi, Kusai

    2016-01-01

    Objective: This study was aimed to assess the effect of anodized and alkali-heat surface treatment on the bioactivity of titanium alloy (Ti-6Al-4V) after immersion in Hank's solution for 7 days. Materials and Methods: Fifteen titanium alloy samples were used in this study. The samples were divided into three groups (five for each), five samples were anodized in 1M H3PO4 at constant voltage value of 20 v and another five samples were alkali-treated in 5 M NaOH solution for 25 min at temperature 60°C followed by heat treatment at 600°C for 1 h. All samples were then immersed in Hank's solution for 7 days to assess the effect of surface modifications on the bioactivity of titanium alloy. The different treated surfaces and control one were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transformation infra-red spectroscopy. Statistical analysis was performed with PASW Statistics 18.0® (Predictive Analytics Software). Results: Anodization of Ti-alloy samples (Group B) led to the formation of bioactive titanium oxide anatase phase and PO43− group on the surface. The alkali-heat treatment of titanium alloy samples (Group C) leads to the formation of bioactive titania hydrogel and supplied sodium ions. The reaction between the Ti sample and NaOH alkaline solution resulted in the formation of a layer of amorphous sodium titania on the Ti surface, and this layer can induce apatite deposition. Conclusions: The surface roughness and surface chemistry had an excellent ability to induce bioactivity of titanium alloy. The anodization in H3PO4 produced anatase titanium oxide on the surface with phosphate originated from electrolytes changed the surface topography and allowed formation of calcium-phosphate. PMID:27382532

  14. 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

  15. Highly proton conductive phosphoric acid-nonionic surfactant lyotropic liquid crystalline mesophases and application in graphene optical modulators.

    PubMed

    Tunkara, Ebrima; Albayrak, Cemal; Polat, Emre O; Kocabas, Coskun; Dag, Ömer

    2014-10-28

    Proton conducting gel electrolytes are very important components of clean energy devices. Phosphoric acid (PA, H(3)PO(4) · H2O) is one of the best proton conductors, but needs to be incorporated into some matrix for real device applications, such as into lyotropic liquid crystalline mesophases (LLCMs). Herein, we show that PA and nonionic surfactant (NS, C(12)H(25)(OCH(2)CH(2))(10)OH, C(12)E(10)) molecules self-assemble into PANS-LLCMs and display high proton conductivity. The content of the PANS-LLCM can be as high 75% H(3)PO(4) · H2O and 25% 10-lauryl ether (C(12)H(25)(OCH(2)CH(2))(10)OH, C(12)E(10)), and the mesophase follows the usual LLC trend, bicontinuous cubic (V1)-normal hexagonal (H1)-micelle cubic (I1), by increasing the PA concentration in the media. The PANS-LLCMs are stable under ambient conditions, as well as at high (up to 130 °C) and low (-100 °C) temperatures with a high proton conductivity, in the range of 10(-2) to 10(-6) S/cm. The mesophase becomes a mesostructured solid with decent proton conductivity below -100 °C. The mesophase can be used in many applications as a proton-conducting media as well as a phosphate source for the synthesis of various metal phosphates. As an application, we demonstrate a graphene-based optical modulator using supercapacitor structure formed by graphene electrodes and a PANS electrolyte. A PANS-LLC electrolyte-based supercapacitor enables efficient optical modulation of graphene electrodes over a range of wavelengths, from 500 nm to 2 μm, under ambient conditions.

  16. 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

  17. Resin–dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding

    PubMed Central

    Sauro, Salvatore; Toledano, Manuel; Aguilera, Fatima Sánchez; Mannocci, Francesco; Pashley, David H.; Tay, Franklin R.; Watson, Timothy F.; Osorio, Raquel

    2013-01-01

    Objective To compare resin–dentin bond strengths and the micropermeability of hydrophobic vs. hydrophilic resins bonded to acid-etched or EDTA-treated dentin, using the ethanol wet-bonding technique. Methods Flat dentin surfaces from extracted human third molars were conditioned before bonding with: 37% H3PO4 (15 s) or 0.1 M EDTA (60 s). Five experimental resin blends of different hydrophilicities and one commercial adhesive (SBMP: Scotchbond Multi-Purpose) were applied to ethanol wet-dentin (1 min) and light-cured (20 s). The solvated resins were used as primers (50% ethanol/50% comonomers) and their respective neat resins were used as the adhesive. The resin-bonded teeth were stored in distilled water (24 h) and sectioned in beams for microtensile bond strength testing. Modes of failure were examined by stereoscopic light microscopy and SEM. Confocal tandem scanning microscopy (TSM) interfacial characterization and micropermeability were also performed after filling the pulp chamber with 1 wt% aqueous rhodamine-B. Results The most hydrophobic resin 1 gave the lowest bond strength values to acid-etched dentin and all beams failed prematurely when the resin was applied to EDTA-treated dentin. Resins 2 and 3 gave intermediate bond strengths to both conditioned substrates. Resin 4, an acidic hydrophilic resin, gave the highest bond strengths to both EDTA-treated and acid-etched dentin. Resin 5 was the only hydrophilic resin showing poor resin infiltration when applied on acid-etched dentin. Significance The ethanol wet-bonding technique may improve the infiltration of most of the adhesives used in this study into dentin, especially when applied to EDTA-treated dentin. The chemical composition of the resin blends was a determining factor influencing the ability of adhesives to bond to EDTA-treated or 37% H3PO4 acid-etched dentin, when using the ethanol wet-bonding technique in a clinically relevant time period. PMID:20074787

  18. [Preparation, characterization and adsorption performance of mesoporous activated carbon with acidic groups].

    PubMed

    Li, Kun-Quan; Li, Ye; Zheng, Zheng; Zhang, Yu-Xuan

    2013-06-01

    Mesoporous activated carbons containing acidic groups were prepared with cotton stalk based fiber as raw materials and H3PO4 as activating agent by one step carbonization method. Effects of impregnation ratio, carbonization temperature and heat preservation time on the yield, elemental composition, oxygen-containing acid functional groups and adsorptive capacity of activated carbon were studied. The adsorption capacity of the prepared activated carbon AC-01 for p-nitroaniline and Pb(II) was studied, and the adsorption mechanism was also suggested according to the equilibrium experimental results. The maximum yield of activated carbons prepared from cotton stalk fiber reached 35.5% when the maximum mesoporous volume and BET surface area were 1.39 cm3 x g(-1) and 1 731 m2 x g(-1), respectively. The activated carbon AC-01 prepared under a H3 PO4/precursor ratio of 3:2 and activated at 900 degrees C for 90 min had a total pore volume of 1.02 cm3 x g(-1), a micoporous ratio of 31%, and a mesoporous ratio of 65%. The pore diameter of the mesoporous activated carbon was mainly distributed in the range of 2-5 nm. The Langmuir maximum adsorption capacities of Pb(II) and p-nitroaniline on cotton stalk fiber activated carbon were 123 mg x g(-1) and 427 mg x g(-1), respectively, which were both higher than those for commercial activated carbon fiber ACF-CK. The equilibrium adsorption experimental data showed that mesopore and oxygen-containing acid functional groups played an important role in the adsorption. PMID:23947073

  19. 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

  20. 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.