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1

Pilot production of activated carbon from cotton stalks using H 3PO 4  

Microsoft Academic Search

Cotton stalks, an agricultural waste, were chemically activated in a batch process using H3PO4 in a locally designed carbonizer at 420°C in the absence of any purging gases. Mechanically cut short sticks were soaked in diluted H3PO4 for a short duration (Batch 1) and an extended period (Batch 2) prior to thermal treatment. The derived carbons contained both coarse and

Badie S. Girgis; Edward Smith; Mamdouh M. Louis; Abdel-Nasser A. El-Hendawy

2009-01-01

2

Anodic film growth on antimony in H 3PO 4 solutions  

Microsoft Academic Search

The anodic oxidation of Sb in H3PO4 solutions is studied within the frame of an investigation concerning the mechanism of the initial stages of anodic film growth on metals. In this special case, so-called induction periods of constant potential preceding the quasi-linear potential rise in a galvanostatic experiment are explained by a semiconductor layer formation on the Sb electrode. Proofs

M. Bojinov; I. Kanazirski; A. Girginov

1995-01-01

3

Hydrothermal and conventional H 3PO 4 activation of two natural bio-fibers  

Microsoft Academic Search

Two phosphoric acid activation procedures; Activation after Hydrothermal Impregnation (recently published) and Activation after Incipient Wetness Impregnation instead of conventional impregnation are analyzed in two natural bio-fiber precursors: banana pseudostem and coconut fiber matting. Both procedures are compared analyzing, in both precursors, the influence that variables such as H3PO4\\/precursor ratio, activation temperature and impregnation time have on the resulting activated

A. J. Romero-Anaya; M. A. Lillo-Ródenas; C. Salinas-Martínez de Lecea; A. Linares-Solano

4

HI extraction by H 3PO 4 in the Sulfur–Iodine thermochemical water splitting cycle: Composition optimization of the HI\\/H 2O\\/H 3PO 4\\/I 2 biphasic quaternary system  

Microsoft Academic Search

Iodine excess separation from hydriodic acid (HI) is one of the most challenging steps of the Sulfur–Iodine thermochemical water splitting cycle. One promising method is the extraction of HI by using phosphoric acid (H3PO4), with the subsequent separation of gaseous hydriodic acid from water and H3PO4 by a distillation step.The aim of the present work is to provide new experimental

M. Lanchi; F. Laria; R. Liberatore; L. Marrelli; S. Sau; A. Spadoni; P. Tarquini

2009-01-01

5

Studies of performance degradation of a high temperature PEMFC based on H 3PO 4-doped PBI  

Microsoft Academic Search

In this paper, a 600h life test of a high temperature PEMFC based on phosphoric acid (H3PO4)-doped polybenzimidazole (PBI) (H3PO4\\/PBI HT-PEMFC) at a current density of 714mAcm?2 (the beginning 510h continuous test) and 300mAcm?2 (the last 90h intermittent test) was carried out. After the life test, degradation of the MEA occurred. The H2 crossover rate through the PBI membrane and

Gang Liu; Huamin Zhang; Jingwei Hu; Yunfeng Zhai; Dongyan Xu; Zhi-gang Shao

2006-01-01

6

Characterization of the PSG\\/Si interface of H 3PO 4 doping process for solar cells  

Microsoft Academic Search

The precipitation of P in the emitter region of H3PO4 spray doped silicon for solar cell applications has been investigated by electron microscopy, X-ray microanalysis and electrical measurements after annealing for two different times. P, Si and O concentration profiles show that the composition of the phosphorous silicate glass (PSG) is in agreement with a solid solution of P2O5 in

A. Armigliato; D. Nobili; S. Solmi; G. Blendin; B. Schum; A. Lachowicz; J. Horzel

2011-01-01

7

Characterization of H3PO4-treated rice husk adsorbent and adsorption of copper(II) from aqueous solution.  

PubMed

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

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

2014-01-01

8

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

PubMed

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

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

9

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

PubMed Central

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

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

2014-01-01

10

Influence of HNO3/H3PO4-NANO2 mediated oxidation on the structure and properties of cellulose fibers.  

PubMed

The bamboo pulp cellulose fiber was oxidized with HNO3/H3PO4-NaNO2 mixture to obtain oxidized cellulose containing different levels of carboxyl content and with high yields. The effects of HNO3/H3PO4-NaNO2 mediated oxidation on structure and properties of the fiber were investigated. The results showed that an increase in carboxyl content and weight loss of oxidized fibers appeared with increasing oxidation time. Compared with the original cellulose, the oxidized fibers had lower crystallinity (29-40%) and thermal stability. The patterns of (13)C NMR, X-ray diffraction and other testing methods revealed that the oxidation mostly occurred at C6 primary hydroxyl groups of cellulose. Moreover, an oxidized fiber with 94.14-98.59% of high yields and 1.13-3.56% of carboxyl content was obtained in the range of oxidation time from 15 to 60min, while its mechanical properties did not change significantly. This work presented some detailed information about structure-property correlations of oxidized bamboo pulp cellulose fibers and was useful in planning applications of these products. PMID:25037436

Xu, Yunhui; Liu, Xin; Liu, Xuelan; Tan, Jiulong; Zhu, Hongling

2014-10-13

11

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

PubMed

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

Adamiak, Joanna; Kalinowska-Alichnewicz, Dorota; Szadkowski, Micha?; Skupi?ski, Wincenty

2011-11-15

12

Marine Sponge/H3PO4: As a Naturally Occurring Chiral Catalyst for Solvent-free Fischer-Indole Synthesis  

PubMed Central

Background A new and efficient method have been developed for the synthesis of different indole derivatives from various ketones, having at least one hydrogen atom attached to each of their ?-carbon atoms, and hydrazines in solvent-free conditions, using marine sponge/H3PO4 as a naturally occurring chiral catalyst. Objectives This study recommended the use of marine sponge/H3PO4 as a naturally occurring chiral catalyst for preparation of phenylhydrazones from ketones having one ?-hydrogen and subsequent cyclisation of the products to indoles. Materials and Methods The reaction was carried out by mixing the phenylhydrazine, ketone, and marine sponge/H3PO4 powder in mortar and pestle; the mixture was ground at room temperature in an appropriate time until TLC show the completion of the reaction. The product extracted by CH2Cl2 and evaporation of solvent yields the products. Results In this research work, several indoles are synthesized using phenylhydrazine and aliphatic or aromatic ketone as starting materials, in the presence of marine sponge/H3PO4 powder as a natural catalyst under solvent-free condition. Conclusions We found marine sponge/H3PO4 to be an effective catalyst for indolisation of phenylhydrazones from ketones having ?-hydrogens in solvent-free conditions.

Shushizadeh, Mohammad Reza; Mostoufi, Azar; Badri, Rashid; Azizyan, Somaye

2013-01-01

13

Ferroelectric phase transition in hydrogen-bonded 2-aminopyridine phosphate (NC4H4NH2).H3PO4  

NASA Astrophysics Data System (ADS)

A new crystal of 2-aminopyridine phosphate (NC4H4NH2).H3PO4 has been grown and its x-ray structure and physical properties were studied. At room temperature the crystals are monoclinic, space group C2/c. The flat 2-aminopyridine cations are hydrogen bonded to the anionic [PO4 ] groups. The interesting feature of the crystal structure is the three-dimensional network of hydrogen bonds including, among others, two strong, symmetrical O . . . H, H . . . O interactions with disordered proton locations. Symmetrically related PO4 anions linked through these protons form infinite (PO4)infty chains along the crystal a-axis. The anomalies in the temperature dependence of the electric permittivity showed that the crystal undergoes ferroelectric phase transition at Tc = 103.5 K. The spontaneous polarization takes place along the crystal a-axis, being parallel to the chains of the hydrogen-bonded PO4. The disordered protons, thermally activated at room temperature, can be frozen at their positions in the ferroelectric phase. The order-disorder continuous type of the transition has been evidenced on the basis of the temperature dependences of electric permittivity and spontaneous polarization measurements.

Czapla, Z.; Dacko, S.; Waskowska, A.

2003-06-01

14

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

PubMed

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

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

2009-10-14

15

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

16

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

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

17

Characterization and lead adsorption properties of activated carbons prepared from cotton stalk by one-step H 3PO 4 activation  

Microsoft Academic Search

Activated carbons were prepared from cotton stalk by one-step H3PO4 activation and used as adsorbent for the removal of lead(II). Taguchi experimental design method was used to optimize the preparation of the adsorbents. The results showed that the optimized conditions were: impregnation with a 50% (w\\/v) phosphoric acid solution with a mass ratio of 3:2 and activation temperature at 500°C

Kunquan Li; Zheng Zheng; Ye Li

2010-01-01

18

An efficient preparation of beta-aryl-beta-ketophosphonates by the TFAA/H3PO4-mediated acylation of arenes with phosphonoacetic acids.  

PubMed

Beta-aryl-beta-ketophosphonates can be efficiently prepared in good yield by using a TFAA/85% H 3PO 4-mediated acylation of electron-rich arenes with phosphonoacetic acids. The conditions offer advantages over existing methods of preparing these useful compounds by not requiring the use of strong base, cryogenics, or an anhydrous and inert atmosphere. Furthermore, some functional groups not tolerated with the reaction conditions used in existing methods are compatible with the herein described conditions. PMID:18642870

Luke, George P; Seekamp, Christopher K; Wang, Zhe-Qing; Chenard, Bertrand L

2008-08-15

19

HNO 3\\/H 3PO 4–NANO 2 mediated oxidation of cellulose — preparation and characterization of bioabsorbable oxidized celluloses in high yields and with different levels of oxidation  

Microsoft Academic Search

The reaction of cellulose with a mixture of HNO3\\/H3PO4–NaNO2 (2:1:1.4, v\\/v\\/%w) at room temperature for different time intervals has been investigated to produce oxidized cellulose (OC), a biocompatible and bioresorbable polymer. The results revealed an increase in carboxyl content of OC with increasing reaction time, corresponding to about 8.0, 13.4, 17.4 and 18.4% carboxyl content after 12, 24, 36, and

Vijay Kumar; Tianrun Yang

2002-01-01

20

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

PubMed

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

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

2013-09-01

21

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

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

22

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

PubMed

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

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

2007-11-01

23

Modelling, analysis and optimization of adsorption parameters for H3PO4 activated rubber wood sawdust using response surface methodology (RSM).  

PubMed

Adsorption capacity of Cu(2+) from aqueous solution onto H(3)PO(4) activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out, the thermodynamic parameters like standard Gibb's free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (DeltaS degrees) were evaluated. The pseudo-second-order model was found to explain the kinetics of Cu(2+) adsorption most effectively. The process optimization was performed through Central Composite Rotary Design using response surface methodology (RSM) by Design Expert Version 5.0.7 (STAT-EASE Inc., Minneapolis, USA). An initial concentration of 35 mg L(-1), temperature of 26 degrees C, carbon loading of 0.45 g(100mL)(-1), adsorption time 208 min and pH of 6.5 was found to be the optimum conditions for the maximum uptake of copper ions of 5.6 mg g(-1) in batch mode. PMID:19155164

Kalavathy, Helen M; Regupathi, Iyyaswami; Pillai, Magesh Ganesa; Miranda, Lima Rose

2009-04-01

24

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

25

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

PubMed

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

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

2014-01-30

26

Effect of different micro-plasma arc welding (MPAW) processes on the corrosion of AISI 316L SS tubes in LiBr and H 3PO 4 solutions under flowing conditions  

Microsoft Academic Search

This work studies the corrosion under flowing conditions of four kinds of AISI 316L materials welded by the micro-plasma arc welding technique in different media: a basic (LiBr) and an acidic (H3PO4) solution by means of polarization measurements. Sensitization tests, galvanic corrosion evaluation, microstructural analyses and microhardness tests have been also carried out. Corrosion parameters revealed that, among the materials

R. Sánchez-Tovar; M. T. Montañés; J. García-Antón

2010-01-01

27

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)

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

Pellett, Gerald

2005-01-01

28

Synthesis and crystal structure of a new open-framework iron phosphate (NH 4) 4Fe 3(OH) 2F 2[H 3(PO 4) 4]: Novel linear trimer of corner-sharing Fe(III) octahedra  

Microsoft Academic Search

A new iron phosphate (NH4)4Fe3(OH)2F2[H3(PO4)4] has been synthesized hydrothermally at HF concentrations from 0.5 to 1.2mL. Single-crystal X-ray diffraction analysis reveals its three-dimensional open-framework structure (monoclinic, space group P21\\/n (No. 14), a=6.2614(13)Å, b=9.844(2)Å, c=14.271(3)Å, ?=92.11(1)°, V=879.0(3)Å3). This structure is built from isolated linear trimers of corner-sharing Fe(III) octahedra, which are linked by (PO4) groups to form ten-membered-ring channels along [100].

Jin-Xiao Mi; Cheng-Xin Wang; Ning Chen; Rong Li; Yuanming Pan

2010-01-01

29

Bibliographies of Industrial Interest: Thermodynamic Measurements on the Systems CO2-H2O, CuCl2-H2O, H2SO4-H2O, NH3-H2O, H2S-H2O, ZnCl2-H2O, and H3PO4-H2O.  

National Technical Information Service (NTIS)

Contained herein are bibliographies of sources of experimental and correlated thermodynamic data for seven binary aqueous mixtures of industrial importance, namely mixtures of CO2, H2S, NH3, H2SO4, H3PO4, CuCl2 and ZnCl2 with water. The categories of equi...

B. R. Staples D. Garvin D. Smith-Magowan T. L. Jobe J. Crenca

1986-01-01

30

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

NASA Technical Reports Server (NTRS)

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.

Perez-Davis, Marla E.; Difilipo, Frank

1990-01-01

31

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...

32

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

PubMed

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

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

2013-10-01

33

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

NASA Astrophysics Data System (ADS)

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).

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

2014-03-01

34

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

PubMed

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

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

2004-12-15

35

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)

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.

Meade, Charles; Jeanloz, Raymond

1990-01-01

36

Cycle-life improvement of Zn/NiOOH cells by the addition of Ca(OH)2 to the zinc electrode  

NASA Astrophysics Data System (ADS)

The addition of Ca(OH)2 to the zinc electrode of Zn/NiOOH cells was investigated in order to determine its effect on reducing the rate of Zinc redistribution. Cells containing 0, 10, 25, and 40 mol percent Ca(OH)2 in the zinc electrode were constructed and tested. Ca(OH)2 was found to form a calcium zincate complex with the zincate supersaturated KOH solution created during the discharge half-cycle. As Ca(OH)2 is insoluble in the electrolyte, the formation of this complex (containing two Zn atoms to one Ca) significantly reduces the Zinc redistribution rate. Electrodes with only 10 percent Ca(OH)2 were found to contain insufficient Ca(OH)2 to complex with enough Zinc to make a dramatic improvement on cycle life. The 25 percent-Ca(OH)2 electrodes, however, were found to retain their capacity beyond 150 deep discharge cycles, with indication that further Zinc redistribution would occur very slowly. The Zinc utilization of the Ca-containing electrodes showed dramatic improvement over the Ca-free zinc electrodes.

Jain, Rajiv; McLarnon, Frank R.; Cairns, Elton J.

1989-08-01

37

Kinetics and mechanism of direct reaction between CO2 and Ca(OH)2 in micro fluidized bed.  

PubMed

Even at present it is still difficult to characterize the reaction between CO2 and Ca(OH)2 at high temperature and atmospheric pressure using traditional instruments such as thermogravimetric analyzer and differential scanning calorimeter. This study was devoted to characterizing such a reaction in a newly developed micro fluidized bed reaction analyzer (MFBRA) under isothermal conditions in the temperature range of 773-1023 K. The results indicated that the MFBRA has not only a good adaptability for characterizing the above-mentioned reaction but enables as well a new insight into the mechanism of the reaction. An obvious time delay was identified for the release of the formed steam (H2O) in comparison with the onset of its CO2 absorption, which might be attributed to the formation of an unstable intermediate product Ca(HCO3)2 in the reaction process between CO2 and Ca(OH)2. The activation energy for forming Ca(HCO3)2 was found to be about 40 kJ/mol, which is much lower than that of the reaction between CO2 and CaO. PMID:23734593

Yu, Jian; Zeng, Xi; Zhang, Guangyi; Zhang, Juwei; Wang, Yin; Xu, Guangwen

2013-07-01

38

The protective efficiency of galvanizing against corrosion of steel in mortar and in Ca(OH) 2 saturated solutions containing chlorides  

Microsoft Academic Search

The behaviour of galvanized steel in Ca(OH)2 saturated solutions containing either no additives, chloride or chloride plus nitrite has been studied. The behaviour of galvanized steel in mortar specimens containing the same types of additives has been simultaneously analysed. The results show that the critical chloride threshold for galvanized steel is higher than that for bare steel before the transition

E. Ramirez; J. A. González; A. Bautista

1996-01-01

39

Preparation of high surface area CaCO 3 by reacting CO 2 with aqueous suspensions of Ca(OH) 2: Effect of the addition of sodium polyacrylate  

Microsoft Academic Search

High surface area CaCO3 was produced through the reaction between CO2 and an aqueous suspension of Ca(OH)2 with the addition of an additive, sodium polyacrylate. The surface area of CaCO3 prepared was affected markedly by the amount of additive and the solution pH when adding the additive. The CaCO3 with the highest surface area (87.7±1.3 m2\\/g) was obtained under the conditions

Jung-Hsin Yang; Shin-Min Shih

2009-01-01

40

Activated carbons from yellow poplar and white oak by H 3PO 4 activation  

Microsoft Academic Search

Results are presented from continuing investigations of the phosphoric acid activation of hardwoods. Earlier work with white oak has been extended to include yellow poplar. It is found that the same general chemical and physical changes occur with both precursors. A discussion is presented on the possible mechanisms of phosphoric acid activation, drawing upon extensive research on the use of

Marit Jagtoyen; Frank Derbyshire

1998-01-01

41

Characterization of mesoporous carbon prepared from date stems by H3PO4 chemical activation  

NASA Astrophysics Data System (ADS)

The present work was focused on the determination of texture, morphology, crystanillity and oxygenated surface groups characteristics of an activated carbon prepared from date stems. Chemical activation of this precursor at different temperatures (450, 550 and 650 °C) was adopted using phosphoric acid as dehydrating agent at (2/1) impregnation ratio. Fourier transform infrared spectroscopy study was carried out to identify surface groups in date stems activated carbons. The microscopic structure was examined by nitrogen adsorption at 77 K. The interlayer spacing (d200 and d100), stack height (Lc), stack width (La) and effective dimension L of the turbostratic crystallites (microcrystallite) in the date stems activated carbons were estimated from X-ray diffraction data (XRD). Results yielded a surface area, SBET, and total pore volume of 682, 1455, 1319 m2/g and 0,343, 1,045 and 0.735 cm3/g, for the carbon prepared at 450, 550 and 650 °C, respectively. Scanning electron microscopy exhibits a highly developed porosity which is in good agreement with the porous texture derived from gas adsorption data and these results confirm that the activated carbon is dominated by network of slit-shaped mesopores morphology and in some cases by varied micropores morphologies.

Hadoun, H.; Sadaoui, Z.; Souami, N.; Sahel, D.; Toumert, I.

2013-09-01

42

Synthesis, characterization, and electrochemical application of Ca(OH)2-, Co(OH)2-, and Y(OH)3-Coated Ni(OH)2 tubes.  

PubMed

We report on the synthesis, characterization, and electrochemical application of Ca(OH)2-, Co(OH)2-, and Y(OH)3-coated Ni(OH)2 tubes with mesoscale dimensions. These composite tubes were prepared via a two-step chemical precipitation within an anodic alumina membrane under ambient conditions. The morphology and structure of the as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) equipped with energy dispersive spectroscopy (EDS). The results showed that the size of the tubes was of mesoscale dimension and the proportion of the tube morphology was about 95%. The as-prepared composite tubes were further investigated as the positive-electrode materials of rechargeable alkaline batteries. Electrochemical measurements revealed that the Ni(OH)2 tubes coated with Ca(OH)2, Co(OH)2, and Y(OH)3 exhibited superior electrode properties including high discharge capacity, excellent high-temperature and high-rate discharge ability, and good cycling reversibility. The mechanism analysis suggests that both the coated layers and the unique hollow-tube structures play an indispensable role in optimizing the electrochemical performance of nickel hydroxide electrodes. PMID:16852761

Li, Weiyang; Zhang, Shaoyan; Chen, Jun

2005-07-28

43

Effects of Ca(OH)2 assisted aluminum sulfate coagulation on the removal of humic acid and the formation potentials of tri-halomethanes and haloacetic acids in chlorination.  

PubMed

The effects of addition of calcium hydroxide on aluminum sulphate (or alum) coagulation for removal of natural organic matter (NOM) and its subsequent effect on the formation potentials of two major types of regulated disinfection byproducts (DBPs), haloacetic acids (HAAs) and trihalomethanes (THMs), have been examined. The results revealed several noteworthy phenomena. At the optimal coagulation pH (i.e. 6), the coagulation behavior of NOM water solutions versus alum dose, showed large variation and a consequent great change in the formation potentials of the DBPs at certain coagulant doses. However, with addition of a relatively small amount of Ca(OH)2, although the zeta potential of coagulated flocs remained almost the same, NOM removal became more consistent with alum dose. Importantly, also the detrimental effect of charge reversal on NOM removal at the low coagulant dose disappeared. This resulted in a steady decrease in the formation potentials of DBPs as a function of the coagulant dose. Moreover, the addition of Ca(OH)2 broadened the pH range of alum coagulation and promoted further reduction of the formation potentials of the DBPs. The enhancement effects of Ca(OH)2 assisted alum coagulation are especially pronounced at pH 7 and 8. Finally, synchronous fluorescence spectra showed that the reduction in DBPs formation potential by Ca(OH)2-assisted alum coagulation was connected to an enhanced removal of small hydrophobic and hydrophilic HA molecules. Ca(OH)2-assistance of alum coagulation appeared to increase substantially the removal of the hydrophilic HA fraction responsible for HAAs formation, prompting further reduction of HAA formation potentials. PMID:23520868

Duan, Jinming; Cao, Xiaoting; Chen, Cheng; Shi, Dongrui; Li, Genmao; Mulcahy, Dennis

2012-01-01

44

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

PubMed

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

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

2002-12-01

45

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

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

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

2014-01-21

46

Analysis on porous aluminum anodic oxide film formed in Re–OA–H 3PO 4 solution  

Microsoft Academic Search

An anodic porous film on aluminum was prepared in a mixed electrolyte of phosphoric acid and organic acid and cerium salt. The growth, morphology and chemical composition of the film were investigated. The results indicate that the growth of porous layers in this solution undergo three stages during anodizing, as in other conventional solution, while the whole growth rate is

H. Wang; H. W. Wang

2006-01-01

47

Ionic Conductivity in Irradiated KCl.  

National Technical Information Service (NTIS)

The ionic conductivity of X and gamma irradiated KCl single crystals has been studied between room temperature and 600 deg C. The radiation induced damage resulting in a decrease of the conductivity heals by thermal annealing in two steps which are at abo...

J. Vignolo Rubio

1979-01-01

48

Corrosion behaviour of micro-plasma arc welded stainless steels in H 3PO 4 under flowing conditions at different temperatures  

Microsoft Academic Search

This paper studies the general corrosion behaviour of the micro-plasma arc welded AISI 316L stainless steel in phosphoric acid at different temperatures (25–60°C) and at a Reynolds number of 1456. Galvanic corrosion has been studied using zero-resistance ammeter (ZRA) measurements and polarization curves (by the mixed potential theory). Results show that the microstructure of the stainless steel is modified due

R. Sánchez-Tovar; M. T. Montañés; J. García-Antón; A. Guenbour; A. Ben-Bachir

2011-01-01

49

Absorption of colloidal silver in KCl  

Microsoft Academic Search

The optical extinction coefficient of colloidal silver formed in KCl in connection with the thermal dissociation of Ag- centers is investigated. Changes with annealing of the position, half-width, and height of the extinction band are reported. An explanation based on the Mie theory is given in which account is taken of the limitation of electron mean free path by surface

W. Kleemann

1968-01-01

50

Thermoluminescence and isothermal annealing kinetics of the F-centres in x- irradiated KCl and KCl:KNOâ  

Microsoft Academic Search

The annealing characteristics of F centers in KCl and KCl: KNOâ ; single crystals and the accompanying glow were studied. Results support the view ; that no connection exists between the F-center decay and thermoluminescence. ; (DLC);

1973-01-01

51

Laser characteristics of KCL:O2(-)  

NASA Astrophysics Data System (ADS)

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

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

1983-10-01

52

Equations of state for solid NaCl-KCl and liquid NaCl-KCl-H(sub 2)O.  

National Technical Information Service (NTIS)

The equilibrium between the solid solution of NaCl-KCl and the ternary liquid NaCl-KCl-H(sub 2)O is both scientifically interesting and geologically important. Equations of the Margules type have been derived for the two phases that accurately reproduce t...

K. S. Pitzer S. M. Sterner

1991-01-01

53

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  

Microsoft Academic Search

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

Gerald L. Pellett

1996-01-01

54

Functionally graded coatings of HA–G–Ti composites and their in vivo studies  

Microsoft Academic Search

Hydroxyapatite (HA) was synthesized by the wet chemical method using phosphoric acid (H3PO4) and calcium hydroxide Ca(OH)2 aqueous solutions. The prepared HA powders were fired at various temperatures ranging from 200 to 1200 °C for 2 h to obtain different degrees of crystallinity. The HA powders having different crystallinities were mixed with glass (G) in different weight percentages to form

R. Roop Kumar; S Maruno

2002-01-01

55

Thermal conductivity of pressure-induced recrystallized KCl  

Microsoft Academic Search

The thermal conductivities of four specimens of pressure-induced recrystallized (PIR) KCl have been measured between 1.8 and 90°K. At the lowest temperatures, the conductivities of these compressively deformed specimens are lower than the single-crystal conductivity by as much as one order of magnitude. The reductions in conductivity for PIR KCl specimens are much smaller than are observed in hot-pressed CdS

M. Jirmanus; H. H. Sample

1974-01-01

56

Optical properties of KCl:Sn2+ phosphors synthesized from aqueous KCl/SnCl2 solutions  

NASA Astrophysics Data System (ADS)

KCl:Sn2+ phosphors were synthesized from aqueous KCl/SnCl2 solutions. Solvents with a molar ratio of KCl : SnCl2 = 1 : M (M = 0 - 5) were dissolved in de-ionized water. The optical properties of the synthesized phosphors were investigated by photoluminescence (PL) analysis, PL excitation spectroscopy (PLE), and PL lifetime measurements. KCl:Sn2+ phosphor synthesized with M = 0.1 exhibited the strongest PL emission in the green (AT band) and red spectral regions (R band). The phosphors synthesized with M >= 1 were composites of various potassium chlorostannates and emitted light in the red spectral region (R band). Annealing the M = 0.1 phosphor in dry N2 resulted in a PL spectrum that was the same as those usually observed in melt-grown KCl:Sn2+ phosphors (i.e., exhibiting only the AT emission band). Annealing also led to a change in the PL decay characteristic from a double exponential curve to a single exponential curve. The AT and R emission bands had nearly the same PLE spectra and were related to the deexcitation of the Sn2+ (5s5p) ions in KCl.

Nara, Jun-Ichi; Adachi, Sadao

2011-12-01

57

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

SciTech Connect

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

Dai, Lian-Xin; Sakashita, Haru; Tatsumi, Takashi (Univ. of Tokyo (Japan))

1994-05-01

58

RESEARCH NOTES: Directional electric breakdown of KCl single crystals  

Microsoft Academic Search

Controversy exists about whether the discharge channel existing after breakdown in alkali halide crystals marks the path of the electronic instability or results from secondary processes. A fast electro-optical shutter has been used to observe the pre-breakdown light emission from KCl single crystals, and it has been found that the discharge channel does lie in the path of the electronic

R. Cooper; C. T. Elliott

1968-01-01

59

Radiation Effects on beta 10.6 of Pure and Europium Doped KCl.  

National Technical Information Service (NTIS)

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 measur...

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

1975-01-01

60

KCl:Dy phosphor for thermoluminescence dosimetry of ionizing radiation.  

PubMed

The thermoluminescence (TL) characterizations of ?-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 ?-irradiation doses. Peak TL intensities varied sublinearly with ?-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 ?-ray dose. TL peak height was found to be dependant on the concentration (0.05-0.5 mol%) of added Dy in the host. PMID:23255424

Bhujbal, P M; Dhoble, S J

2013-01-01

61

Study of silver atoms in anionic position in KCL  

NASA Astrophysics Data System (ADS)

The local geometry and electronic distribution of silver atoms trapped in anionic centres (Ag-a(0)) of KCl has been studied by means of Density Functional Theory (DFT) and cluster models involving up to 123 ions. This leads to an important outwards relaxation of the metal-ligand distance of about 13.1% with respect to the pure lattice (RK-Cl =3.14 Angstrom), which plays an important role for understanding experimental EPR data. The higher stability and more localised nature of this centre, compared to Ag-0 at a cationic site (Ag-c(0)), is shown to be related to the energy difference between the Ag(5s) level and the conduction band. The charge distribution in the a(1g) level for Ag-a(0) and Ag-c(0) are compared. These results allow one to understand the different hyperfine constants due to both centres in KCl.

Garcia-Fernandez, P.; Aramburu, J. A.; Barriuso, M. T.; Moreno, M.

62

Phase transformation rate in shock-loaded KCL  

NASA Astrophysics Data System (ADS)

Previous experimental data on shocked single crystal KCl, between 20 and 40 kbar, displayed the B1-->B2 phase transformation. Stress histories at the impact surface provided information on phase change kinetics: very rapid transformation to a non-equilibrium, metastable state followed by a slower transformation to the equilibrium state. In the current study, we analyzed the transmitted wave profiles, which yielded additional insight on the phase transformation kinetics of KCl. Our analyses do not conclusively determine these rates as different methods of analysis give different estimates. It is clear, however, that the transformation rate for [100] crystals was larger than estimated previously. The study also demonstrates that strength effects may play an important role on both the P2 arrival time and on the transient drop in stress observed behind the P1 wave as measured at the rear quartz gauge, and that transformation rate effects may be confounded with strength effects in these experiments behind P1 wave. .

Ding, Jow-Lian; Hayes, Dennis

2000-04-01

63

Molecular-resolution imaging of pentacene on KCl(001)  

PubMed Central

Summary The growth of pentacene on KCl(001) at submonolayer coverage was studied by dynamic scanning force microscopy. At coverages below one monolayer pentacene was found to arrange in islands with an upright configuration. The molecular arrangement was resolved in high-resolution images. In these images two different types of patterns were observed, which switch repeatedly. In addition, defects were found, such as a molecular vacancy and domain boundaries.

Neff, Julia L; Gotzen, Jan; Li, Enhui; Marz, Michael

2012-01-01

64

Positron states in KCL crystals before and after radiation exposure  

NASA Astrophysics Data System (ADS)

The features of positron annihilation in KCl crystals before and after radiation exposure is investigated. A significant increase in the efficiency of the “ortho-vapor” process of positronium state conversion is detected. A model is proposed for taking part in the “ortho-vapor” conversion of conduction electrons drawn into the conduction band by a positron field that affords a qualitative interpretation of the results obtained and permits values of the electron concentration in a spur to be obtained.

Aref'ev, K. P.; Boev, O. V.; Bondarenko, A. L.

1988-07-01

65

[Photostimulated luminescence properties of KCl:Cu+ after UV excitation].  

PubMed

KCl:Cu+ powder sample was prepared with high temperature solid reaction process. After being excited by UV, the sample shows near ultraviolet blue luminescence by stimulation with 560 nm light. The research result indicates that Cu+ acts as a luminous center, and Cu+ does not change into Cu2+ by UV irradiation. So, Cu+ ions do not act as hole traps, while anion vacancies act as electron traps. Once UV excited sample is stimulated, electrons from F center combine with hole trapping center or VK center, and cause subsequent energy transfer to Cu+ ion. Then, a character emission attributed to d-s transition of Cu+ in lattice occurs. PMID:16395928

Sun, Li; Wang, Yong-sheng; Zhao, Su-ling; Xu, Zheng; Xue, Wei-wei

2005-10-01

66

Quantum diffusion of muonium in KCl and NaCl  

NASA Astrophysics Data System (ADS)

We present an analysis of the quantum diffusion of muonium in KCl and NaCl crystals, which has been observed experimentally by Kiefl and co-workers. We have demonstrated that all specific low temperature features of D(T) are due to the two-phonon interaction with account taken of the real phonon spectrum. The anomalous behaviour at high T is explained by the effect of “fluctuational preparation of the barrier”. Taking both ideas into consideration we found a reasonable theoretical description of the D versus T dependence in a wide temperature range.

Kagan, Yu.; Prokofev, N. V.

1990-11-01

67

Theoretical and empirical investigations of KCl:Eu2+ for nearly water-equivalent radiotherapy dosimetry  

PubMed Central

Purpose: The low effective atomic number, reusability, and other computed radiography-related advantages make europium doped potassium chloride (KCl:Eu2+) a promising dosimetry material. The purpose of this study is to model KCl:Eu2+ point dosimeters with a Monte Carlo (MC) method and, using this model, to investigate the dose responses of two-dimensional (2D) KCl:Eu2+ storage phosphor films (SPFs). Methods: KCl:Eu2+ point dosimeters were irradiated using a 6 MV beam at four depths (5–20 cm) for each of five square field sizes (5×5–25×25 cm2). The dose measured by KCl:Eu2+ was compared to that measured by an ionization chamber to obtain the magnitude of energy dependent dose measurement artifact. The measurements were simulated using DOSXYZnrc with phase space files generated by BEAMnrcMP. Simulations were also performed for KCl:Eu2+ films with thicknesses ranging from 1 ?m to 1 mm. The work function of the prototype KCl:Eu2+ material was determined by comparing the sensitivity of a 150 ?m thick KCl:Eu2+ film to a commercial BaFBr0.85I0.15:Eu2+-based SPF with a known work function. The work function was then used to estimate the sensitivity of a 1 ?m thick KCl:Eu2+ film. Results: The simulated dose responses of prototype KCl:Eu2+ point dosimeters agree well with measurement data acquired by irradiating the dosimeters in the 6 MV beam with varying field size and depth. Furthermore, simulations with films demonstrate that an ultrathin KCl:Eu2+ film with thickness of the order of 1 ?m would have nearly water-equivalent dose response. The simulation results can be understood using classic cavity theories. Finally, preliminary experiments and theoretical calculations show that ultrathin KCl:Eu2+ film could provide excellent signal in a 1 cGy dose-to-water irradiation. Conclusions: In conclusion, the authors demonstrate that KCl:Eu2+-based dosimeters can be accurately modeled by a MC method and that 2D KCl:Eu2+ films of the order of 1 ?m thick would have minimal energy dependence. The data support the future research and development of a KCl:Eu2+ storage phosphor-based system for quantitative, high-resolution multidimensional radiation therapy dosimetry.

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

2010-01-01

68

Eu-Doped KCl storage phosphor for erasable and rewritable optical memory utilizing photostimulated luminescence phenomenon  

NASA Astrophysics Data System (ADS)

Intense photostimulated luminescence (PSL) with a peak at 420 nm is observed in ultraviolet (UV) Iight-irradiated europium-doped potassium chloride (KCl: Eu) crystalline phosphors. The PSL characteristics of UV-irradiated KCl: Eu phosphor for optical memory application were studied. The excitation and emission mechanisms of the 420 nm PSL, which are consistent with the results obtained, are discussed.

Nanto, Hidehito; Endo, Fumitaka; Hirai, Yoshiaki; Nasu, Shouichi; Takeuchi, Nozomu

1994-01-01

69

Force generation in experimental tetanus, KCl contracture, and oxygen and glucose deficiency contracture in mammalian myocardium  

Microsoft Academic Search

We studied the amount and time-course of tension recovery after quick releases (0.25 mm) during experimental tetanus, potassium chloride contracture (KCl), hypoxic contracture (H) as well as joint glucose and oxygen deficiency contracture (HG) in left ventricular papillary muscles of rat and right ventricular papillary muscles of cat myocardium. Both in experimental tetanus and KCl contracture, the tension recovery was

Ch. Holubarsch

1983-01-01

70

Solution Hardening and Softening in KCl-KBr Single Crystals at Low Temperatures  

Microsoft Academic Search

The temperature and concentration dependence of the critical resolved shear stress (CRSS) for KCl and KCl-KBr solid solutions was measured from 4.2 K to 293 K. At lower temperatures the solid solutions with the concentration below 10 mol% KBr and above 90 mol% KBr showed solution softening. The other concentrations of solid solutions were hardened at all temperatures tested. The

Toshihiko Kataoka; Teruyoshi Uematsu; Tomoharu Yamada

1978-01-01

71

Phototransferred Thermoluminescence of KCL:Eu2+ Dosemeters  

NASA Astrophysics Data System (ADS)

The phototransferred thermoluminescence (PTTL) of KCl:Eu2+ crystals was studied after exposure to X -rays or ? radiation. The main thermoluminescence (TL) peaks were found around 370, 390 and 470 K. The 470 K highest intensity peak is considered to be the dosimetric peak due to its low fading and linear dose behavior. The main dosimetric peak is sharply decreased after illumination with UV light of a previously irradiated specimen. The PTTL is wavelength dependent and has been shown to peak in the 220 - 230 nm region and 650 nm in previously non irradiated and irradiated samples, respectively. The PTTL spectral response is always a broad band around 390 - 490 nm peaked at 425 nm, which is related to the well-known Eu2+ emission.

Barboza-Flores, M.; Meléndrez, R.; Chernov, V.; Bernal, R.; Piters, T. M.; Pérez-Salas, R.; Aceves, R.; Pedroza-Montero, M.; Castañeda, B.

2001-04-01

72

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

SciTech Connect

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.

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

1997-02-09

73

LETTER TO THE EDITOR: Luminescence from KCl co-doped with Eu2+ and Eu3+ ions  

NASA Astrophysics Data System (ADS)

Distinct holes are found in the blue emission from KCl co-doped with divalent and trivalent europium ions. This extraordinary emission feature is associated with the process of reabsorption from Eu2+ to Eu3+ ions in KCL.

Jun-Gill, Kang; Min-Kook, Nah; Youngku, Sohn

2000-03-01

74

Selective Deposition of UCl 4and (KCl) x(UCl 4) yinside Carbon Nanotubes Using Eutectic and Noneutectic Mixtures of UCl 4with KCl  

NASA Astrophysics Data System (ADS)

UCl 4and compositions of the form (KCl) x(UCl 4) yhave been selectively deposited inside multiple-walled carbon nanotubes (MWTs) via capillary action using both eutectic and noneutectic mixtures of UCl 4with KCl. The deposition conditions were determined from the pseudobinary KCl-UCl 4phase diagram, which contains two eutectic melting compositions at 50 mol% KCl:50 mol% UCl 4and 73.2 mol% KCl:26.8 mol% UCl 4, and also from surface tension/composition data reported in the literature. The encapsulated products were investigated by HRTEM and EDX incorporating both nanometer and sub-nanometer scale electron probes. Following preliminary characterization, the selectively encapsulated UCl 4was allowed to oxidize in air for 14 days, but only a relatively small amount (ca. 2%) of a crystalline oxidized product of the form U(Cl, O) xwas observed inside the MWTs. Some MWTs selectively filled with UCl 4showed evidence of spiraling (helical) crystal growth.

Sloan, J.; Cook, J.; Chu, A.; Zwiefka-Sibley, M.; Green, M. L. H.; Hutchison, J. L.

1998-10-01

75

Structure of CO2 adsorbed on the KCl(100) surface.  

PubMed

The structure and dynamics of the adsorbate CO(2)/KCl(100) from a diluted phase to a saturated monolayer have been investigated with He atom scattering (HAS), low-energy electron diffraction (LEED), and polarization dependent infrared spectroscopy (PIRS). Two adsorbate phases with different CO(2) coverage have been found. The low-coverage phase is disordered at temperatures near 80 K and becomes at least partially ordered at lower temperatures, characterized by a (2?2×?2)R45° diffraction pattern. The saturated 2D phase has a high long-range order and exhibits (6?2×?2)R45° symmetry. Its isosteric heat of adsorption is 26 ± 4 kJ mol(-1). According to PIRS, the molecules are oriented nearly parallel to the surface, the average tilt angle in the saturated monolayer phase is 10° with respect to the surface plane. For both phases, structure models are proposed by means of potential calculations. For the saturated monolayer phase, a striped herringbone structure with 12 inequivalent molecules is deduced. The simulation of infrared spectra based on the proposed structures and the vibrational exciton approach gives reasonable agreement between experimental and simulated infrared spectra. PMID:21524129

Traeger, Franziska; Hadnadjev, Milica; Vogt, Jochen; Weiss, Helmut

2011-06-30

76

Dissolution rates of NaCl and KCl in aqueous solution  

NASA Astrophysics Data System (ADS)

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

Simon, B.

1981-04-01

77

Thermal analysis and kinetics of the TiH\\/sub x\\/\\/KClOâ system  

Microsoft Academic Search

A combined experimental and theoretical study of the system TiH\\/sub x\\/\\/KClOâ has been undertaken to investigate the thermodynamic and kinetic aspects of initiation of the TiH\\/sub x\\/\\/KClOâ pyrotechnic system and to obtain parameters of interest in mathematical modeling of the initiation and propagation from a hot bridgewire source. Experimental results along with kinetic computations are of interest in understanding the

J. W. Reed; C. L. Fread

1977-01-01

78

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

Microsoft Academic Search

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

Ken Shuang

2009-01-01

79

KCl Cotransport Regulation and Protein Kinase G in Cultured Vascular Smooth Muscle Cells  

Microsoft Academic Search

K-Cl cotransport is activated by vasodilators in erythrocytes and vascular smooth muscle cells and its regulation involves putative kinase\\/phosphatase cascades. N-ethylmaleimide (NEM) activates the system presumably by inhibiting a protein kinase. Nitrovasodilators relax smooth muscle via cGMP-dependent activation of protein kinase G (PKG), a regulator of membrane channels and transporters. We investigated whether PKG regulates K-Cl cotransport activity or mRNA

N. C. Adragna; J. Zhang; M. Di Fulvio; T. M. Lincoln; P. K. Lauf

2002-01-01

80

K+-Cl? cotransporter-2 KCC2 in chicken cardiomyocytes  

PubMed Central

Using antibodies prepared against a unique region (exon 22–24) of rat K+-Cl? cotransporter-2 (KCC2), we confirmed that the ?140-kDa KCC2 protein is exclusively expressed in rat brain, but in chicken, we observed strong reactivity not only with the ?140-kDa KCC2 protein in brain but also a slightly larger ?145-kDa protein in heart. In silico analysis showed that while exon 22 of KCC2 is unique to this isoform in therian mammals, it is retained in KCC2's closest paralog, KCC4, of lower vertebrates, including chicken. To eliminate potential cross-reactivity with chicken KCC4, the antibodies were preadsorbed with blocking peptides prepared over the only two regions showing significant sequence identity to chicken KCC4. This completely eliminated antibody recognition of exogenously expressed chicken KCC4 but not of the ?145-kDa protein in chicken heart, indicating that chicken heart expresses KCC2. Real-time PCR confirmed robust KCC2 transcript expression in both chicken brain and heart. Chicken heart expressed predominantly the longer KCC2a splice variant consistent with the larger ?145-kDa protein in chicken heart. Immunofluorescence microscopy revealed prominent plasma membrane KCC2 labeling in chicken ventricular cardiomyocytes. We hypothesize that KCC2 is an important Cl? extrusion pathway in avian cardiomyocytes that counters channel-mediated Cl? loading during high heart rates with ?-adrenergic stimulation. While KCC2 is absent from mammalian cardiomyocytes, understanding the role that the other KCC isoforms play in Cl? homeostasis of these cells represents a nascent area of research.

Antrobus, Shane P.; Lytle, Christian

2012-01-01

81

Effect of partial substitution of NaCl with KCl on proteolysis of halloumi cheese.  

PubMed

The effect of substitution of NaCl with Potassium chloride (KCl) in brine solution on proteolysis of halloumi cheese was investigated. Halloumi cheeses were made and kept in 4 different brine solutions (18% w/w), including only NaCl (HA; control); 3NaCl:1KCl (w/w) (HB); 1NaCl:1KCl (w/w) (HC); 1NaCl:3KCl (w/w) (HD); and stored for 56 d at 4 °C. Proteolysis was assessed using water-soluble nitrogen (WSN), trichloroacetic acid-soluble nitrogen (TCA-SN), phosphotungstic-soluble nitrogen (PTA-SN), urea polyacrylamide gel electrophoresis (urea-PAGE), and peptide patterns. WSN and TCA-SN contents were similar in all experimental cheeses. Peptide patterns of the pH 4.6 N fraction and urea-PAGE showed no significant difference between halloumi cheeses kept in various NaCl/KCl mixtures (HB, HC, HD) and control (HA). Sodium and potassium contents showed positive correlations with WSN and PTA-SN. There was an inverse correlation between calcium (Ca) contents and WSN and PTA-SN. Correlations between Ca and Na or K were negative at the same salt treatment. PMID:21535650

Ayyash, Mutamed M; Shah, Nagendra P

2011-01-01

82

Ionic mobility and dielectric relaxation in supercooled liquid KCl-glycerol solutions  

NASA Astrophysics Data System (ADS)

Measurements of the electrical conductivities of liquid and supercooled liquid KCl-glycerol solutions between + 50·6°C and -89·1°C are described. Time domain measurements of dielectric relaxation in pure glycerol between -78·1°C and -91·0°C, and in KCl-glycerol solutions between -77·5°C and -89·1°C are also described. Empirical equations are presented which in each case describe the non-Arrhenius temperature dependence over more than 12 decades in value with a r.m.s. deviation of less than 15 per cent. A 'power law' fit is found to be slightly better than a 'Vogel-Tammann-Fulcher' fit in each case. The temperature dependence of Walden product for KCl-glycerol solutions is discussed, and the relaxation data for pure glycerol is discussed in the light of the Kauzmann paradox.

Champeney, D. C.; Ould Kaddour, F.

83

Highly oriented POPOP films grown on the KCl(0 0 1) surface  

NASA Astrophysics Data System (ADS)

Some simple aromatic molecules have interesting electro-optical properties and potential for use in organic opto-electronic devices. The structure of thin films of the electroluminescent molecule POPOP (1,4-bis(5-phenyloxazol-2-yl)benzene) grown in vacuum on KCl(0 0 1) substrates was studied with grazing-incidence X-ray diffraction. POPOP films consist of monoclinic bulk-like crystallites with (1 0 2) POPOP?(0 0 1) KCl which show a strong preferential orientation with [0 1 0] POPOP?[1 1 0] KCl. The microstructure of the films is characterized by needle-shaped crystallites forming 90°, 180°, and some 45° domain walls. The morphology of the films is determined by an internal (1 0 2) molecular packing plane in the bulk POPOP structure and the corrugation of the substrate.

Smilgies, Detlef-M.; Boudet, Nathalie; Struth, Bernd; Yamada, Yuya; Yanagi, Hisao

2000-11-01

84

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

86

Optical absorptions and photochemical conversions of paramagnetic defects in KClO3 and KClO4 at 26 K  

Microsoft Academic Search

The optical absorption of KClO3 crystals irradiated with x-rays at 26 K are assigned to paramagnetic defects by correlating the changes in the optical absorption and ESR spectrum observed during annealing and selective bleaching. The polarization of the absorption bands and structure of the defects derived earlier by ESR indicate that three transitions involve charge transfer within the electron-excess defects:

Nis Bjerre; J. R. Byberg

1981-01-01

87

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

SciTech Connect

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

Zheng Yuanshui; Han Zhaohui; Driewer, Joseph P.; Low, Daniel A.; Li, H. Harold [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

2010-01-15

88

Laser-stimulable transparent KCl:Eu crystals for erasable and rewritable optical memory utilizing photostimulated luminescence  

NASA Astrophysics Data System (ADS)

Intense photostimulated luminescence (PSL) with a peak at 420 nm is observed in ultraviolet (UV)-light-irradiated europium-doped potassium chloride (KCl:Eu) single crystals. The PSL characteristics of UV-irradiated KCl:Eu for optical memory application are studied. The excitation and emission mechanisms of the 420 nm PSL, which are consistent with the results obtained, are discussed.

Nanto, Hidehito; Murayama, Kazuhiko; Usuda, Takayuki; Endo, Fumitaka; Hirai, Yoshiaki; Taniguchi, Shin-Ichi; Takeuchi, Nozomu

1993-07-01

89

Comparison of TiH/sub X/- and ZrH/sub X/-KClO sub 4 Pyrotechnics.  

National Technical Information Service (NTIS)

Pyrotechnic properties of ZrH/sub x//KClO sub 4 blends have been compared with those previously obtained for TiH/sub x//KClO sub 4 blends. The results indicate that the dependence of spark sensitivity on fuel microstructure found for the latter materials ...

M. L. Lieberman R. S. Carlson C. T. Rittenhouse J. W. Fronabarger

1982-01-01

90

Infrared Spectroscopy of the Stretching Modes of SeH- and TeH- in KCl and KBr.  

National Technical Information Service (NTIS)

The fundamental stretching modes near 4.5 micrometers of SeH(-) and TeH(-) doped in KCl and KBr are measured at high resolution at 1.7 K. For the KCl-doped samples, prepared by adding elemental Se(Te) to the melt and growing under H2, the concentrations o...

C. E. Mungan U. Happek T. Z. Hossain A. J. Sievers

1995-01-01

91

Micellization and clouding phenomenon of amphiphilic antidepressant drug amitriptyline hydrochloride: effect of KCl.  

PubMed

In the present study, we report the micellization and clouding behavior of an amphiphilic antidepressant drug viz., amitriptyline hydrochloride (AMT) at different fixed temperatures and KCl concentrations in aqueous solutions. The critical micelle concentration (cmc) of AMT, as measured by conductivity method, increases with increasing temperature and decreasing with KCl concentration. The thermodynamic parameters viz., standard Gibbs energy (?G(m)(0)), standard enthalpy (?H(m)(0)), and standard entropy (?S(m)(0)) of micellization of AMT are evaluated. The values clearly indicate more stability of the AMT solution in presence of KCl. Like surfactant, AMT also shows phase separation behavior. The cloud point (CP) of AMT in water decreases with increase in pH of the medium because of the deprotonation of the drug molecule. The CP values increase with increasing KCl concentration and AMT concentrations, clearly indicating the micellar growth at higher concentration. Furthermore, for better understanding of the behavior of drug molecule in water, we evaluated various thermodynamic parameters of the above drug molecule at CP. PMID:22172338

Alam, Md Sayem; Samanta, Debasis; Mandal, Asit Baran

2012-04-01

92

ESR OF Ti(III) in LiCl-KCl Eutectic  

Microsoft Academic Search

Study of corrosion phenomena associated with the use of molten salts as coolants raised interest in the behaviour of various metal ions in such melts. Gruen & McBeth, in the early sixties, studied various transition metal ions in LiCl\\/KCl eutectic. The purpose of the present letter is an attempt to correlate ESR data with data derived from optical spectroscopy, in

N. Beukema; D. C. Koningsberger; J. L. Verbeek

1969-01-01

93

Low-Temperature Coloration in KCl and KBr near the Fundamental Edge  

Microsoft Academic Search

Crystals of KCl and KBr have been cooled with liquid helium, x rayed, and investigated for coloration near their fundamental absorption edge. Three bands are seen in both materials with the largest band closest to the fundamental edge. In KBr the first band is broad and peaks at 2300 Å, the second is the alpha band at 2020 Å, and

Clifford C. Klick; David A. Patterson

1963-01-01

94

Measurements of Pressure for the TiH/sub X//KClO sub 4 System.  

National Technical Information Service (NTIS)

An investigation was conducted to measure the pressure obtained when the pyrotechnic mixture TiH/sub x//KClO sub 4 was ignited in a confined variable-volume system. It was possible to derive an expression of the form PV/sup gamma / = k for the pressure-vo...

C. H. H. Chong J. E. Glaub

1978-01-01

95

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium  

Microsoft Academic Search

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

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

2010-01-01

96

Thermal Stability of the F' Center in KCl Between 80 and 300 K.  

National Technical Information Service (NTIS)

After shining an F spark light of high intensity upon a colored sample of KCl, the annealing of the induced F' band and the decay of the induced luminescence are observed. This luminescence is produced by the electrons returning to the anion vacancies thr...

C. Garcia Cordovila

1974-01-01

97

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

NASA Technical Reports Server (NTRS)

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.

Holleck, G. L.

1971-01-01

98

Facilitation by clonidine of purine release induced by high KCl from the rabbit pulmonary artery.  

PubMed

1 The effect of clonidine on the 3H-purine release evoked by KCl or (-)-adrenaline was assessed in the superfused helical strip of the rabbit pulmonary artery pretreated with [3H]-adenosine. 2 Clonidine (3 x 10(-5) M to 10(-4) M) significantly enhanced the 3H-purine efflux evoked by 50 mM KCl but not by 3 x 10(-6) M) (-)-adrenaline. 3 This facilitatory effect of clonidine on the KCl-induced purine release was unaltered by phentolamine 3 x 10(-6) M. It was absent in arterial segments denervated with 6-hydroxydopamine 30 microgram/ml. 4 A sustained contractile response was evoked by clonidine 3 x 10(-5) M without an increase in the 3H-purine efflux. This was significantly reduced by phentolamine 3 x 10(-6) M, but not by yohimbine 10(-5) M or by denervation with 6-hydroxydopamine. 5 The uptake of [3H]-adenosine into the segments was not inhibited by clonidine 3 x 10(-5) M. 6 It is suggested that the facilitation by clonidine of the KCl-induced purine release is due to prevention of presynaptic autoinhibition of purine release from adrenergic nerves, by an antiadenosine action of the drug. PMID:7296170

Katsuragi, T; Su, C

1981-11-01

99

Effect of Plastic Deformation on the Thermoluminescence of gamma-Irradiated KCl Crystals  

Microsoft Academic Search

The effect of plastic deformation on the thermoluminescence of nominally pure Harshaw KCl samples gamma irradiated at room temperature has been studied up to 450 °C. In samples plastically strained prior to irradiation a new glow peak appears. It has been found that this glow peak does not follow either first- or second-order kinetics. It is shown that the phosphorescence

V. Ausín; J. L. Alvarez Rivas

1972-01-01

100

Chemiluminescent emission spectra and possible upper-state potentials of KCl and KBr  

Microsoft Academic Search

Chemiluminescent optical spectra of potassium chloride and potassium bromide have been observed in dilute flames. In the KCl spectra 56 ``fluctuation bands'' could be resolved. A table of 66 such bands were measured for KBr, extending the observed spectral range by about 1000 Å to the red for this molecule. Possible upper-state potential curves accounting for the observations are proposed.

Kenneth J. Kaufmann; James L. Kinsey; Howard B. Palmer; Archibald Tewarson

1974-01-01

101

Electrical Resistivity of TiH/sub X/KClO sub 4.  

National Technical Information Service (NTIS)

Various factors affecting the electrical resistivity of the pyrotechnic pressed powder TiH/sub x//KClO sub 4 , which is sensitive to hot wire ignition yet quite spark insensitive, were evaluated. The electrical resistivity of the TiH/sub x/ (x = 0.19-1.9,...

K. White J. W. Reed C. M. Love J. A. Holy J. E. Glaub

1978-01-01

102

Volume properties of melts of the KF-KCl-HfFâ system  

Microsoft Academic Search

Starting salts of purity grade cp were prepared; the hafnium fluoride was purified by double vacuum distillation. Experimental data were reduced using the method of least squares; results are presented for the measurements of the density of the fused mixtures of the KF-KCl-HfFâ. The highest concentration of hafnium fluoride in the mixtures was limited to 50 mole % due to

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

1988-01-01

103

Modelling of TiH/sub X//KClO sub 4 Actuator Pyrotechnic Output.  

National Technical Information Service (NTIS)

Pyrotechnic output generated by TiH/sub x//KClO sub 4 loaded actuators has been modelled through an analysis of the applicable forces and utilization of relevant piston velocity (VISAR) and load cell data. The assumption of a linearly decreasing force-tim...

M. L. Lieberman S. E. Benzley

1978-01-01

104

Load Cell Testing of TiH/sub X//KClO sub 4 Pyrotechnic Actuators.  

National Technical Information Service (NTIS)

A load cell test has been utilized to characterize ignition time, function time, and pyrotechnic output of TiH/sub x//KClO sub 4 loaded actuators. Pyrotechnic material parameter variations include (1) fuel and oxidizer particle sizes for 33/67 TiH sub 0 ....

M. L. Lieberman

1978-01-01

105

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

PubMed Central

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

Oren, Aharon

2013-01-01

106

Some properties of KCl-filled microelectrodes: Correlation of potassium “leakage” with tip resistance  

Microsoft Academic Search

Summary This study was undertaken in order to determine directly the rates of K leakage (JK) out of the tips of microelectrodes into a solution of 100 mM KCl (approximating the K concentration of the cell interior) and to relate these rates to the concentration of the filling solution and the tip resistance. The values ofJK for electrodes filled with

Michael Fromm; Stanley G. Schultz

1981-01-01

107

Photochemical Reaction and Photoconductivity of Additively Colored KCl Crystals at Low Temperature  

Microsoft Academic Search

The change in the photoconductivity of KCl crystals containing F centers upon optical bleaching of the F band has been investigated at low temperature. It was shown that the presence of M centers is not responsible for the residue of the photoconductivity in the F band region at low temperature. F' centers were produced through a tunneling process when F

Takehiko Ishii; Teiichi Endo

1968-01-01

108

Solid Solution Softening and Solid Solution Hardening in Concentrated KCl-KBr Model Crystals  

Microsoft Academic Search

The dislocation motion at 0 K overcoming the concentrated solute atoms is calculated by a relaxation method using the string model. The concentration dependence of yield stress tauy with Peierls barrier agrees with experimental data, and softening is revealed in c{=}0.04, where c is the concentration of KBr in KCl. The softening is due to the enhancement of double kink

Masao Sakamoto

1984-01-01

109

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

PubMed Central

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

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

2009-01-01

110

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

PubMed

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

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

2009-08-01

111

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

PubMed Central

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).

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

2013-01-01

112

Role of endothelium, acetylocholine and calcium ions in Bay K8644- and KCl-induced contraction.  

PubMed

The aim of this study was to establish the involvement of acetylcholine (Ach) and calcium ions in modulating contractions induced by Bay K8644 (an agonist of calcium channels located in the cell membrane) and KCl (at depolarizing concentrations), and also to examine the importance of the vascular endothelium in the activity of Bay K8644. The study was performed on perfused Wistar rat tail arteries. Contraction induced by Bay K8644 with the participation of intracellular (in calcium?free physiological salt solution, FPSS) and extracellular (in physiological salt solution, PSS, following the emptying of the cellular Ca2+ stores) pools of Ca2+ and the addition of nitro-L-arginine (L?NNA; nitric oxide synthase inhibitor) or 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ; an inhibitor of soluble guanylyl cyclase) was studied. In addition, the effect of Ach on the contraction response was analyzed and the results were compared with the depolarizing action of KCl. The effects of 8Br?cGMP on the artery contraction induced by Bay K8644 prior to and following removal of the endothelium were compared. Bay K8644 and KCl in PSS induced vascular contraction, which was reduced with the addition of Ach. The spasmolytic Ach action did not occur in the presence of L?NNA and ODQ. 8Br?cGMP reduced the contraction of arterial walls (with and without endothelium) induced by Bay K8644. The increase in vascular tone induced by Bay K8644 and KCl was independent of the intracellular calcium ion pool. The relaxant effect of Ach on the responses stimulated by Bay K8644 and KCl indicated the participation of nitric oxide in modulating the reactivity of the arteries to the factors examined, resulting in an influx of Ca2+ into the cell. PMID:23836047

Szadujkis-Szadurska, Katarzyna; Grzesk, Grzegorz; Szadujkis-Szadurski, Leszek; Gajdus, Marta; Malinowski, Bartosz; Wicinski, Michal

2013-09-01

113

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

PubMed

Recent research has demonstrated that europium doped potassium chloride (KCl:Eu(2+)) 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 chips. The purposes of this work are to quantify the performance of KCl:Eu(2+) 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:Eu(2+) 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:Eu(2+) 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% 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:Eu(2+-)-based dosimeter could become a versatile and durable dosimetry tool with large dynamic range (sub-cGy to 100 Gy). PMID:23735856

Li, H Harold; Xiao, Zhiyan; Hansel, Rachael; Knutson, Nels; Yang, Deshan

2013-06-21

114

Interspecific interactions between the rare tooth fungi Creolophus cirrhatus, Hericium erinaceus and H. coralloides and other wood decay species in agar and wood  

Microsoft Academic Search

Creolophus cirrhatus, Hericium erinaceus and H. coralloides were paired against over 20 other wood decay fungi from beech (Fagus sylvatica) covering a range of ecological strategies, on 2 % malt agar (MA), 0.5 % MA, 0.5 % MA adjusted to x1.25 MPa by addition of KCl, 0.5 % MA adjusted to pH 4 with KOH\\/H3PO4 and 0.5 % MA under

Paul Wald; Sini Pitkkänen; Lynne Boddy

2004-01-01

115

Production of Activated Carbon from Jojoba Seed Residue by Chemical Activation Residue Using a Static Bed Reactor  

Microsoft Academic Search

The production of chemically activated carbon from Jojoba seed residue was experimentally investigated using a laboratory-scale static bed reactor. The effects of process variables such as activation time, activation temperature, particle size, chemical reagents (KCl, ZnCl2 and H3PO4) and impregnation ratio on adsorption capacity of activated Jojoba seed residue were studied. The highest iodine number and yield were obtained by

Muhammad Tawalbeh; Mamdouh A. Allawzi; Munther I. Kandah

2005-01-01

116

ROCK1 translocates from non-caveolar to caveolar regions upon KCl stimulation in airway smooth muscle.  

PubMed

Airway smooth muscle (ASM) membrane depolarization through KCl opens L-type voltage dependent Ca2+ channels (Ca(v)1.2); its opening was considered the cause of KCl contraction. This substance is used to bypass intracellular second messenger pathways. It is now clear that KCl also activates RhoA/Rho kinase (ROCK) pathway. ROCK isoforms are characterized as ROCK1 and ROCK2. Because ROCK1 seems the most abundant isotype in lung, we studied its participation in KCl stimulated bovine ASM. With methyl-beta-cyclodextrin (MbetaCD) we disrupted caveolae, a membrane compartment considered as the RhoA/ROCK assembly site, and found that KCl contraction was reduced to the same extent (~26%) as Y-27632 (ROCK inhibitor) treated tissues. We confirmed that KCl induces ROCK activation and this effect was annulled by Y-27632 or MbetaCD. In isolated plasmalemma, ROCK1 was localized in non-caveolar membrane fractions in Western blots from control tissues, but it transferred to caveolae in samples from tissues stimulated with KCl. Ca(v)1.2 was found at the non-caveolar membrane fractions in control and MbetaCD treated tissues. In MbetaCD treated tissues stimulated with KCl, contraction was abolished by nifedipine; only the response to Ca(v)1.2 opening remained as the ROCK component disappeared. Our results show that, in ASM, the KCl contraction involves the translocation of ROCK1 from non-caveolar to caveolar regions and that the proper physiological response depends on this translocation. PMID:24397803

Sommer, B; Montano, L M; Chávez, J; Carbajal, V; García-Hernandez, L M; Irles, C; Jiménez-Garduno, A M; Ortega, A

2014-01-01

117

Deficiency of Src family kinases Fgr and Hck results in activation of erythrocyte K/Cl cotransport.  

PubMed

Src-family kinases play a central role in regulation of hematopoietic cell functions. We found that mouse erythrocytes express the Src-family kinases Fgr and Hck, as well as Lyn. To directly test whether Fgr and Hck play any role in erythrocyte function, we analyzed red cells isolated from fgr-/-, hck-/-, and fgr-/- hck-/- knock-out mice. Mean corpuscular hemoglobin concentration and median density are increased, while K content is decreased, in fgr-/- hck-/- double-mutant erythrocytes compared with wild-type, fgr-/-, or hck-/- erythrocytes. Na/K pump and Na/K/Cl cotransport were not altered, but K/Cl cotransport activity was significantly and substantially higher (approximately three-fold) in fgr-/- hck-/- double-mutant erythrocytes. This enhanced K/Cl cotransport activity did not depend on cell age. In fact, in response to bleeding, K/Cl cotransport activity increased in parallel with reticulocytosis in wild-type erythrocytes, while abnormal K/Cl cotransport did not change as a consequence of reticulocytosis in fgr-/- hck-/- double-mutant erythrocytes. Okadaic acid, an inhibitor of a phosphatase that has been implicated in activation of the K/Cl cotransporter, inhibited K/Cl cotransport in wild-type and fgr-/- hck-/- double-mutant erythrocytes to a comparable extent. In contrast, staurosporine, an inhibitor of a kinase that has been suggested to negatively regulate this same phosphatase enhanced K/Cl cotransport in wild-type but not in fgr-/- hck-/- double-mutant erythrocytes. On the basis of these findings, we propose that Fgr and Hck are the kinases involved in the negative regulation of the K/Cl cotransporter-activating phosphatase. Abnormality of erythrocyte K/Cl cotransport in fgr-/- hck-/- double-mutant animals represents the first demonstration that Src-family kinases may be involved in regulation of membrane transport. PMID:9005990

De Franceschi, L; Fumagalli, L; Olivieri, O; Corrocher, R; Lowell, C A; Berton, G

1997-01-15

118

Effect of KCl addition on crystal growth and spectral properties of glycine single crystals  

NASA Astrophysics Data System (ADS)

Glycine usually crystallizes as the metastable ?-polymorph from pure aqueous solution. The polymorph, ?-form of glycine can be crystallized only in presence of additive. In the present work, ?-glycine has been crystallized by using potassium chloride (KCl) as additive at ambient temperature by solvent evaporation method. The form of crystallization is confirmed by X-ray powder diffraction method. Spectroscopic and thermal studies have been carried out for analyzing the presence of functional groups, thermal stability and decomposition of the sample. The results indicate that the KCl is doped into the ?-glycine. The optical transparency of the ?-glycine in the ultraviolet-visible region has been studied by recording the optical transmission spectrum. Second harmonic generation (SHG) conversion efficiency has been estimated as 120 mV and the output power by the crystal is less than that of potassium dihydrogen phosphate crystal.

Sekar, C.; Parimaladevi, R.

2009-12-01

119

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

NASA Astrophysics Data System (ADS)

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

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

1996-01-01

120

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

SciTech Connect

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

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

1988-01-10

121

Longitudinal field quenching studies in KCl and KBr — Evidence for a precursor muonium state  

NASA Astrophysics Data System (ADS)

The repolarization of ?+ in a longitudinal field as a function of field strength has been measured at various temperatures in KCl and KBr single crystals. The data at room temperature in KCl are essentially in agreement with Ivanter et al. /1/ and Nishiyama et al. /5/. The obtained quenching curves can be reasonably fitted by assuming that the long lived muonium state, seen directly in transverse field experiments by Kiefl et al. /4/, is preceded by another short lived muonium state with reduced hf-coupling. It is also necessary to allow for electron spin exchange in the precursor state. The model fits yield the hyperfine frequency of the precursor state, its chemical lifetime and an electron spin flip rate. It is speculated that the precursor state and the temperature dependence of the fitted parameters reflect the early history of the ?+ in its terminal spur.

Gygax, F. N.; Schenck, A.; van der Wal, A. J.; Koch, R.; Winnacker, A.

1986-12-01

122

Evidence for Rh(II) in a LiCl-KCl eutectic. An optical absorption investigation  

Microsoft Academic Search

Rhodium exists in LiCl-KCl melts at 400–450°C as the RhCl63? species. Spectroscopic data show that an increase of the temperature up to 600°C leads to a reaction of this species with the melt and to the formation of the stable (Rh(II) chlorocomplex. This reaction, which has not been reported previously, is reversible since on cooling to lower temperatures, 400–450°C, reoxidation

Ben Gilliams; Jean-Yves Tilquin; Luc Heerman; Jan D'Olieslager; Christaine Görller-Walrand

1997-01-01

123

Study of thermodynamic properties of Np–Al alloys in molten LiCl–KCl eutectic  

Microsoft Academic Search

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

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

2009-01-01

124

Luminescence of KCl:Bi3+ excited at the X absorption band  

Microsoft Academic Search

The emission from KCl:Bi3+ excited in the X absorption band (i.e. between the A and B absorption bands) was measured as a function of temperature. The polarized emission spectrum and the angular dependence of polarization ratio were also investigated. The X-band excitation produces two emission bands peaking at 345 and 395 nm, the centres of which are not the same.

Youn-Doo Kim; Jun-Gill Kang

1994-01-01

125

Calorimetric study of melts in the system KCl–K 2TaF 7  

Microsoft Academic Search

Enthalpy increment measurements on melts in the system KCl–K2TaF7 were carried out by drop calorimetry at temperatures between 298 and 1053, 1093 and 1133K and selected compositions. The heat capacities of melted mixtures and enthalpies of mixing were determined using the experimental data. Calorimetric experiments showed nonideality of the melts in several properties. The molar relative enthalpy and molar heat

I. Nerád; E. Mikšíková

2010-01-01

126

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium  

Microsoft Academic Search

Pyrochemical reprocessing in molten chloride salt medium has been considered as one of the best options for the reprocessing\\u000a of spent metallic fuels of future fast breeder reactors. The unit operations such as salt preparation, electrorefining, and\\u000a cathode processing involve the presence of molten LiCl-KCl eutectic salt from 673 to 1373 K (400 to 1100 °C). The present\\u000a work discusses the corrosion

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

2010-01-01

127

High performance lithium cobalt oxides prepared in molten KCl for rechargeable lithium-ion batteries  

Microsoft Academic Search

Lithium cobalt oxides (LiCoO2) powders have been easily prepared using molten KCl as high-temperature solvent. X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements indicate that the obtained LiCoO2 powders are homogenous and the particle size of LiCoO2 powders can be controlled by flux content and heating time. For a LiCoO2 sample heating at 850 °C for 1 h, at

Hongying Liang; Xinping Qiu; Shicao Zhang; Zhiqi He; Wentao Zhu; Liquan Chen

2004-01-01

128

KCl cotransport activity in light versus dense transferrin receptor-positive sickle reticulocytes.  

PubMed Central

A subset of sickle cells becomes K(+)-depleted and dehydrated before or soon after leaving the bone marrow. These young cells may be identified in blood as transferrin receptor-positive (TfR+) dense reticulocytes. KCl cotransport, which is normally active in young erythroid cells with a maximum at pH 6.8, is a candidate pathway for K+ depletion of sickle reticulocytes. In this investigation, KCl cotransport activity was evaluated in young, TfR+ cells which had become dense in vivo and in age-matched cells which had retained normal hydration. Sickle erythrocytes were first separated into three primary density fractions, with care taken to preserve the in vivo hydration state. After normalization of intracellular hemoglobin concentration with nystatin, the cells were incubated at 37 degrees C for 20 min at pH 6.8 and 7.4. Before and after incubation, each primary fraction was separated into four secondary density fractions. The percentage of TfR+ cells in each secondary fraction was measured and a density distribution for TfR+ cells was determined for each primary fraction before and after incubation. The density shift during incubation was a measure of KCl cotransport. TfR+ cells from the denser primary fractions II and III had significantly more density shift than TfR+ cells from the light fraction I. Although the shifts were larger at low pH, differences between primary fractions were also observed at pH 7.4. These data indicate that the cells which become dense quickly in vivo have more KCl cotransport activity than those which remain light in vivo, and support this pathway as a primary mechanism for dehydration of young sickle cells.

Franco, R S; Palascak, M; Thompson, H; Joiner, C H

1995-01-01

129

Visible and infrared photoluminescence of low-energy electron irradiated LiF:KCl thin films  

Microsoft Academic Search

In this work we report the visible and infrared emissions of the color centers created in bilayer LiF:KCl thin films, obtained by pumping them with appropriate Ar+ and Ti:Sapphire laser lines. The large concentration of color centers induced by low-energy electron irradiation in a thin dielectric layer of controlled depth allows to investigate the spectroscopic properties of point defects which

M. Cremona; A. Grilli; R. M. Montereali; M. Passacantando; A. Raco; F. Somma

1997-01-01

130

Electronic potential energy surfaces for the reaction K+NaCl=KCl+Na  

Microsoft Academic Search

The six lowest ?-bonded potential surfaces for the reaction K+NaCl=KCl+Na have been calculated on a semi-empirical model with a single valence electron in the field of the three closed shell ions. A simple method is proposed by which the energetic effects of valence-core orthogonalization, which are of crucial importance in the calculations, may be included in the potentials of the

A. C. Roach; M. S. Child

1968-01-01

131

Electronic potential energy surfaces for the reaction K+NaCl=KCl+Na  

Microsoft Academic Search

The six lowest sigma-bonded potential surfaces for the reaction K+NaCl=KCl+Na have been calculated on a semi-empirical model with a single valence electron in the field of the three closed shell ions. A simple method is proposed by which the energetic effects of valence-core orthogonalization, which are of crucial importance in the calculations, may be included in the potentials of the

A. C. Roach; M. S. Child

1968-01-01

132

The K+-Cl? cotransporter KCC2 promotes GABAergic excitation in the mature rat hippocampus  

PubMed Central

GABAergic excitatory [K+]o transients can be readily evoked in the mature rat hippocampus by intense activation of GABAA receptors (GABAARs). Here we show that these [K+]o responses induced by high-frequency stimulation or GABAA agonist application are generated by the neuronal K+–Cl? cotransporter KCC2 and that the transporter-mediated KCl extrusion is critically dependent on the bicarbonate-driven accumulation of Cl? in pyramidal neurons. The mechanism underlying GABAergic [K+]o transients was studied in CA1 stratum pyramidale using intracellular sharp microelectrodes and extracellular ion-sensitive microelectrodes. The evoked [K+]o transients, as well as the associated afterdischarges, were strongly suppressed by 0.5–1 mm furosemide, a KCl cotransport inhibitor. Importantly, the GABAAR-mediated intrapyramidal accumulation of Cl?, as measured by monitoring the reversal potential of fused IPSPs, was unaffected by the drug. It was further confirmed that the reduction in the [K+]o transients was not due to effects of furosemide on the Na+-dependent K+-Cl? cotransporter NKCC1 or on intraneuronal carbonic anhydrase activity. Blocking potassium channels by Ba2+ enhanced [K+]o transients whereas pyramidal cell depolarizations were attenuated in further agreement with a lack of contribution by channel-mediated K+ efflux. The key role of the GABAAR channel-mediated anion fluxes in the generation of the [K+]o transients was examined in experiments where bicarbonate was replaced with formate. This anion substitution had no significant effect on the rate of Cl? accumulation, [K+]o response or afterdischarges. Our findings reveal a novel excitatory mode of action of KCC2 that can have substantial implications for the role of GABAergic transmission during ictal epileptiform activity.

Viitanen, Tero; Ruusuvuori, Eva; Kaila, Kai; Voipio, Juha

2010-01-01

133

The K+-Cl cotransporter KCC2 promotes GABAergic excitation in the mature rat hippocampus.  

PubMed

GABAergic excitatory [K(+)](o) transients can be readily evoked in the mature rat hippocampus by intense activation of GABA(A) receptors (GABA(A)Rs). Here we show that these [K(+)](o) responses induced by high-frequency stimulation or GABA(A) agonist application are generated by the neuronal K(+)-Cl() cotransporter KCC2 and that the transporter-mediated KCl extrusion is critically dependent on the bicarbonate-driven accumulation of Cl() in pyramidal neurons. The mechanism underlying GABAergic [K(+)](o) transients was studied in CA1 stratum pyramidale using intracellular sharp microelectrodes and extracellular ion-sensitive microelectrodes. The evoked [K(+)](o) transients, as well as the associated afterdischarges, were strongly suppressed by 0.5-1 mm furosemide, a KCl cotransport inhibitor. Importantly, the GABA(A)R-mediated intrapyramidal accumulation of Cl(), as measured by monitoring the reversal potential of fused IPSPs, was unaffected by the drug. It was further confirmed that the reduction in the [K(+)](o) transients was not due to effects of furosemide on the Na(+)-dependent K(+)-Cl() cotransporter NKCC1 or on intraneuronal carbonic anhydrase activity. Blocking potassium channels by Ba(2+) enhanced [K(+)](o) transients whereas pyramidal cell depolarizations were attenuated in further agreement with a lack of contribution by channel-mediated K(+) efflux. The key role of the GABA(A)R channel-mediated anion fluxes in the generation of the [K(+)](o) transients was examined in experiments where bicarbonate was replaced with formate. This anion substitution had no significant effect on the rate of Cl() accumulation, [K(+)](o) response or afterdischarges. Our findings reveal a novel excitatory mode of action of KCC2 that can have substantial implications for the role of GABAergic transmission during ictal epileptiform activity. PMID:20211979

Viitanen, Tero; Ruusuvuori, Eva; Kaila, Kai; Voipio, Juha

2010-05-01

134

Characterization of Fe/KClO4 heat powders and pellets.  

SciTech Connect

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.

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

2005-04-01

135

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

136

Electrochemical Removal of AlCl3 from LiCl-KCl Melts  

NASA Astrophysics Data System (ADS)

In order to remove impurity AlCl3 from LiCl-KCl melts before Li electrolysis, the Al3+ reduction potential on a tungsten electrode and the relation between Al3+ reduction peak current and AlCl3 concentration in LiCl-KCl-AlCl3 melts were determined by cyclic voltammetry (CV). Constant potential electrolysis at -1.6 V vs Cl2/Cl- on both solid Fe and liquid Zn cathodes was performed to remove AlCl3 impurity from the LiCl-KCl-AlCl3 melts. The removal rate of Al3+ from the melts was analyzed by both electrochemical methods and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The results showed that 96.11 wt pct of Al were removed on a Fe cathode and 99.90 wt pct on a Zn cathode through 10 hours electrolysis, respectively. While stirring the melts by argon gas, 99.21 wt pct of Al3+ was separated from the melts by 4 hours of electrolysis at 723 K (450 °C), which effectively expedited the Al3+ electrochemical reduction rate and shortened the electrolysis time.

Shen, M.; Li, B.; Li, S. Z.; Yu, J. G.

2012-05-01

137

Temperature dependence of the photostimulated luminescence in KCl:Eu2+  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

138

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

139

Heteroepitaxial strain in alkali halide thin films: KCl on NaCl  

NASA Astrophysics Data System (ADS)

We have performed Monte Carlo simulations of the properties of a NaCl (001) surface covered by full or partial layers of KCl, for coverages up to 5 monolayers (ML). A wide variety of structures of the film is found. For integer ML coverages we find the continuous, so-called floating mode rumple structure, as was previously found in the KBr/NaCl system. However, for a coverage of ~2.1 ML, we find a discrete structure of periodicity 3:4 of small regularly spaced KCl pyramids. It has the same scattering characteristics as the structure observed by Henzler et al. [Phys. Rev. B 52, 17 060 (1995)], but it is two-dimensional modulated, rather than the rowlike stacking fault structure proposed by Henzler et al. Also, at a coverage of ~0.8 ML there is a stable 3:4 structure. Other structures are found at intermediate coverages, corresponding to regular arrays of dislocation lines with periodicity 9:10. A further growth from such structures would give rise to growth of a ~5° miscut KCl crystal relative to the NaCl lattice. The reciprocal space patterns corresponding to the continuous and the discrete film deformations are also calculated.

Baker, Jeff; Lindgård, Per-Anker

1999-12-01

140

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

141

Electrolytic recovery of chlorine from hydrogen chloride gas with fused molten salt electrolyte LiCl\\/KCl  

Microsoft Academic Search

A method of electrolytic recovery of chlorine from hydrogen chloride gas based on the fused molten salt LiCl\\/KCl is under development. For the feasibility study, described here, a reticulated vitreous carbon (or porous carbon) cathode was immersed in a low-melting eutectic of LiCl\\/KCl. A graphite rod was used as the anode. Gaseous dilute hydrogen chloride, in a mixture with nitrogen,

Y. Ding; J. Winnick

1996-01-01

142

Calcium-independent phospholipase A 2 participates in KCl-induced calcium sensitization of vascular smooth muscle  

Microsoft Academic Search

In vascular smooth muscle, KCl not only elevates intracellular free Ca2+ ([Ca2+]i), myosin light chain kinase activity and tension (T), but also can inhibit myosin light chain phosphatase activity by activation of rhoA kinase (ROCK), resulting in Ca2+ sensitization (increased T\\/[Ca2+]i ratio). Precisely how KCl causes ROCK-dependent Ca2+ sensitization remains to be determined. Using Fura-2-loaded isometric rings of rabbit artery,

Paul H. Ratz; Amy S. Miner; Suzanne E. Barbour

2009-01-01

143

Ionic Molar Conductivities in Solutions of KCl, NaCl and LiCl in Glycerol at 25°C  

Microsoft Academic Search

Conductivities of solutions of KCl, NaCl and LiCl in glycerol at 25°C have been measured for concentrations in the range 0.0005 to 0.5 mol dm, and values of molar conductivity at infinite dilution obtained by extrapolation. Using previously measured transference numbers for KCl dissolved in glycerol, values of ionic molar conductivities at infinite dilution have been deducted for K, Na,

M. C. Blanco; D. C. Champeney; M. Kameche

1989-01-01

144

Effects of leaf aqueous extract of Bidens pilosa (Asteraceae) on KCl- and norepinephrine-induced contractions of rat aorta  

Microsoft Academic Search

The effect of leaf aqueous extract of Bidens pilosa Linn. on KCl- and norepinephrine-induced contractions of rat aortic strips was studied. In aortic strips with endothelium intact, contractions induced using 60 mM KCl and 10?5 M norepinephrine were dose-dependently relaxed by the extract, a more significant effect being seen with norepinephrine-induced contractions. Following mechanical damage to the aortic endothelium, inhibition

Théophile Dimo; Silver Rakotonirina; René Kamgang; Paul V Tan; Albert Kamanyi; Marc Bopelet

1998-01-01

145

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

PubMed

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

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

2009-11-01

146

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

SciTech Connect

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

Xiao Zhiyan; Hansel, Rachael; Chen Haijian; Du Dongsu; Yang Deshan; Li, H. Harold [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

2013-02-15

147

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

SciTech Connect

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.

Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Allen, Todd [Univ. of Wisconsin, Madison, WI (United States); Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Simpson, Mike [Idaho National Lab., (United States)

2012-11-30

148

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

USGS Publications Warehouse

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.

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

1976-01-01

149

Composition dependence of glow peak temperature in KCl1-xBrx doped with divalent cations  

NASA Astrophysics Data System (ADS)

Thermoluminescence measurements of bgr-irradiated Eu2+- and Ca2+-doped KCl1-xKBrx solid solutions excited at room temperature have been carried out to identify the effect of composition on the glow peaks. A typical glow peak has been distinguished for each composition. A linear dependence of its temperature on the composition x has been found. These results indicate that for divalent impurity-doped alkali halide solid solutions these glow peak temperatures are mostly dependent on the lattice constant of the host than on the size of the anion or impurity cation.

Pérez-Salas, R.; Aceves, R.; Rodríguez-Mijangos, R.; Riveros, H. G.; Duarte, C.

2004-01-01

150

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

PubMed

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

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

2009-09-25

151

Studies on multiphased mixed crystals grown from NaBr and KCl  

NASA Astrophysics Data System (ADS)

We have grown multiphased binary and ternary mixed crystals by the melt method using the miscible alkali halides, viz. NaBr and KCl and physically characterized. Thermal parameters like Debye-Waller factor, Debye temperature, Debye frequency and mean square amplitude of vibration were determined using the X-ray powder diffraction intensity data. DC and AC electrical measurements were carried out by using the parallel plate capacitor method at various temperatures. Activation energies (DC and AC), mean jump frequency, compressibility and mean sound velocity were also determined. The results obtained are reported here.

Padma, C. M.; Mahadevan, C. K.

2008-05-01

152

Effect of temperature on the growth of ultrathin films of p-sexiphenyl on KCl(001)  

NASA Astrophysics Data System (ADS)

Ultrathin films of p-sexiphenyl, formed by vapor-deposition onto KCl(001) substrates, have been investigated by x-ray diffraction (XRD) and atomic force microscopy (AFM). Analysis of the XRD data shows that the temperature of the alkali halide substrate during deposition affects the orientations of the molecules within the adsorbed films. AFM images contribute independent evidence consistent with the XRD results. The results are reproducible and suggest that ultrathin films of p-6P molecules can be grown with desired molecular orientations by carefully selecting the appropriate substrate temperature during deposition. .

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

2004-01-01

153

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

SciTech Connect

The authors discuss tungsten microelectrodes (diam = 25 {mu}m) used to study the deposition and stripping behavior of Li/Li+ and Bi/Bi/sup 3+/ in the LiCl:KCl eutectic at 400{sup 0}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.

Carlin, R.T.; Osteryoung, R.A. (State Univ. of New York, Buffalo, NY (USA). Dept. of Chemistry)

1989-05-01

154

Activation analysis of indium, KCl, and melamine by using a laser-induced neutron source  

NASA Astrophysics Data System (ADS)

A laser-induced repetitively operated fast neutron source with a neutron yield of 4 × 105 n/pulse and a pulse repetition rate of 5 Hz, which was developed using a deuterated polystyrene film target and a 24-TW femtosecond laser, was applied for laser activation analyses of indium, KCl, and melamine samples. The nuclear reactions of the measured gamma spectra for the activated samples were identified as (n, ?), (n, n'), and (n, 2n) reactions. These indicate possible usage of the neutron source for practical activation analyses of various materials.

Lee, Sungman; Lee, Kitae; Cha, Hyungki

2014-04-01

155

Effect of different additives on the thermal properties and combustion characteristics of pyrotechnic mixtures containing the KClO 4\\/Mg–Al alloy  

Microsoft Academic Search

The thermal properties and combustion characteristics of KClO4\\/Mg–50%Al, KClO4\\/Mg–50%Al with additives such as nitrocellulose (NC), urotropine and guanidine nitrate (GN) were studied experimentally using differential thermal analysis (DTA) and thermogravimetry (TG) and closed bomb experiments. The results of DTA–TG analysis revealed that additives could affect thermal stability and the decomposition temperature of KClO4\\/Mg–50%Al alloy. The order of the ignition temperatures

Dehua Ouyang; Gongpei Pan; Hua Guan; Chenguang Zhu; Xin Chen

2011-01-01

156

Nitric oxide synthase-independent release of nitric oxide induced by KCl in the perfused mesenteric bed of the rat.  

PubMed

The aim of the present study was to test whether the contractile responses elicited by KCl in the rat mesenteric bed are coupled to the release of nitric oxide (NO). Contractions induced by 70 mM KCl were coincident with the release of NO to the perfusate. The in vitro exposure to the nitric oxide synthase (NOS) inhibitor L-N(omega)-nitro-L-arginine methyl ester, L-NAME (1-100 microM) potentiated the vascular responses to 70 mM KCl and, unexpectedly, increased the KCl-stimulated release of NO. Moreover, even after the chronic treatment with L-NAME (70 mg/kg/day during 4 weeks), the KCl-induced release of NO was not reduced, whereas the potentiation of contractile responses was indeed achieved. The possibility that NOS had not been completely inhibited under our experimental conditions can be precluded because NOS activity was significantly inhibited after both L-NAME treatments. After the in vitro treatment with 1 to 100 microM L-NAME, the inhibition of NOS was concentration-dependent (from 50% to 90%). With regard to the basal release of NO, the inhibition caused by L-NAME was not concentration-dependent and reached a maximum of 40%, suggesting that basal NO outflow is only partially dependent on NOS activity. An eventual enhancement of NOS activity caused by KCl was disregarded because the activity of this enzyme measured in homogenates from mesenteric beds perfused with 70 mM KCl was significantly reduced. On the other hand, endothelium removal, employed as a negative control, almost abolished NOS activity, whereas the incubation with the Ca(2+) ionophore A23187, employed as a positive control, induced an increase in NOS activity. It is concluded that in the mesenteric arterial bed of the rat, the contractile responses elicited by depolarization through KCl are coincident with a NOS-independent release of NO. This observation, which differs from the results obtained with noradrenaline, do not support the use of KCl as an alternative contractile agent whenever the participation of NO is under study. PMID:11099704

Mendizabal, V E; Poblete, I; Lomniczi, A; Rettori, V; Huidobro-Toro, J P; Adler-Graschinsky, E

2000-12-01

157

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

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.

Chou, I. -M.; Sterner, S. M.; Pitzer, K. S.

1992-01-01

158

Characterization of the moisture absorption behavior of TiH/sub x//KClO/sub 4/  

SciTech Connect

The moisture absorption and desorption behavior of the TiH/sub 0.65//KClO/sub 4/ and TiH/sub 1.65/KClO/sub 4/ pyrotechnic powders are being investigated by mass balancing and nuclear magnetic resonance (NMR) spectroscopic techniques. Moisture absorption and desorption rates have been determined at various points between 50 and 100 percent relative humidities (% RH). Below 92% RH, appreciable moisture is no longer absorbed by these systems. These is a factor of 5 greater moisture absorption at the 95% RH level than at the 92% RH level (0.14 wt. % versus 0.686 wt. % for TiH/sub 0.65//KClO/sub 4/). The rate of moisture absorption is much slower (4 days to absorb maximum amount of moisture) than the rate of desorption (20 minutes for complete desorption). There is also a large difference in the magnitudes of proton spin-lattice relaxation times (211 milliseconds for TiH/sub 0.65//KClO/sub 4/ and 600 to 850 ms for TiH/sub 1.65//KClO/sub 4/). Future studies will concern the effects of the interactions between the titanium and hydrogen nuclei on the line-shape of the high-field (300 MHz), magic-angle sample spinnings, proton NMR spectra of these systems. A quantitative NMR technique for determining the moisture content of these powders will also be developed. 2 refs., 2 figs., 2 tabs.

Attalla, A.; Wang, P.S.

1986-07-01

159

[Inhibitory effect of 18?-glycyrrhetinic acid on KCl- and PE-induced constriction of rat renal interlobar artery in vitro].  

PubMed

The aim of the present study is to investigate the effect of 18?-glycyrrhetinic acid (18?-GA) on KCl- and PE-induced constriction of rat renal interlobar artery (RIA). Pressure myograph system was used to observe the constriction induced by KCl and PE (endothelial independent vasoconstrictor) in acutely separated RIA of Wistar rats with or without 18?-GA pretreatment. Whole-cell patch clamp recordings were used to observe the effect of 18?-GA on membrane input capacitance (Cinput), membrane input conductance (Ginput) or membrane input resistance (Rinput) of smooth muscle cells embedded in arteriole segment. The results showed that both KCl (30-100 mmol/L) and PE (0.1-30 ?mol/L) induced contraction of RIA in a concentration-dependent way. After pretreatment with 18?-GA (100 ?mol/L), KCl- or PE-induced constriction of RIA was significantly decreased. After application of 18?-GA (100 ?mol/L), the Cinput, Ginput and Rinput of the in situ smooth muscle cells were very close to those of dispersed single smooth muscle cells. These results suggest 18?-GA inhibits the contraction induced by KCl and PE, and the underlying mechanism may involve the inhibitory effect of 18?-GA on gap junction. PMID:24777410

Zhang, Wen; Ma, Ke-Tao; Wang, Yang; Si, Jun-Qiang; Li, Li

2014-04-25

160

K-Cl transport systems in rabbit renal basolateral membrane vesicles  

SciTech Connect

The transport pathways for chloride in basolateral membrane vesicles from the rabbit renal cortex were investigated. /sup 36/Cl uptake was stimulated by the presence of potassium in the uptake media compared with sodium of N-methyl-D-glucamine. In addition, potassium (/sup 86/Rb) uptake was stimulated more by chloride than by nitrate or gluconate. Neither of these processes was further stimulated by potassium gradients plus valinomycin, suggesting the presence of an electrically neutral K-Cl cotransport system. A magnesium-induced chloride conductance was also found in the basolateral membrane vesicles. In the absence of magnesium, the chloride conductance was low; valinomycin and an inwardly directed potassium gradient did not stimulated /sup 36/Cl uptake, anthracene-9-carboxylic acid did not inhibit /sup 36/Cl uptake, and valinomycin did not stimulated chloride-dependent /sup 86/Rb uptake. However, in the presence of 1 mM magnesium, opposite results were obtained; valinomycin and an inwardly directed potassium gradient stimulated /sup 36/Cl uptake, anthracene-9-carboxylic acid inhibited /sup 36/Cl uptake, and valinomycin stimulated chloride-dependent /sup 86/Rb uptake. Therefore, an electrically neutral K-Cl cotransport and magnesium-induced chloride conductance were found in renal cortial basolateral membrane vesicles prepared from the rabbit renal cortex.

Eveloff, J.; Warnock, D.G.

1987-05-01

161

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

SciTech Connect

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.

Sandoval, A.

1980-03-01

162

Study on the KCl Fluorescent X-rays for the MicroX Imaging Rocket  

NASA Astrophysics Data System (ADS)

The Micro-X High Resolution Microcalorimeter X-ray Imaging Rocket (Micro-X) is an experiment that combines transition-edge-sensors (TES) with a conical imaging mirror, to obtain high-spectral-resolution images of extended X-ray sources. An Fe-55 source will be set on-board to fluoresce a KCl ring to provide calibration lines of 2.62, 2.81, 3.31 and 3.58 keV, these lines will not interfere with the energy band that Micro-X intends to observe, which is from 0.3 to 2.5 keV. An extensive study has been conducted on how the event rate varies when filters of different materials are put in front of the KCl ring. This study was conducted using charge-coupled-devices (CCD), which are commonly used to detect X-ray events with different energies. The study showed that the source plus a single layer of aluminized mylar (thickness 0.01 mm) will provide enough counts of the desired Cl?, Cl?, K?, and K? lines with little to no events in the 0 to 2 keV energy band.

Rodriguez Lopez, Jose A.; Figueroa-Feliciano, Enectali; Leman, Steven W.; Kissel, Steven

2012-03-01

163

Magneto-optical and microstructural investigations on KClO 3-doped YBCO HTSC  

NASA Astrophysics Data System (ADS)

The influence of KClO 3 addition on the magnetic properties and microstructure of YBCO HTSC materials with nominal composition (A): Y 1Ba 2- xK xCu 3O y, (B): Y 1-0.2 xBa 2-0.2 xK xCu 3O y, (C): Y 1Ba 2Cu 3.5- xK xO y ( x=0-0.75) were investigated. Magneto-optic imaging of flux distributions was employed to study the grain connectivity in the doped and undoped samples in a direct way. The obtained flux patterns taken at various temperatures reveal that KClO 3-doped samples ( x=0.30) exhibit flux distributions being close to those being observed in melt-textured superconductors. This demonstrates that the grain connectivity in the doped samples is considerably improved as compared to pure ones, which is an important issue for the fabrication of coated conductors of YBCO.

Koblischka-Veneva, Anjela; Koblischka, Michael R.; Murakami, Masato

2001-09-01

164

Multicomponent diffusion in molten LiCl-KCl: Dynamical correlations and divergent Maxwell-Stefan diffusivities  

NASA Astrophysics Data System (ADS)

Multicomponent diffusional mechanisms in the ternary LiCl-KCl system are elucidated using the Green-Kubo formalism and equilibrium molecular dynamics simulations. The Maxwell-Stefan (MS) diffusion matrix is evaluated from the Onsager dynamical matrix that contains the diffusion flux correlation functions. From the temporal behavior of the correlation functions, we observe that the Li-Li and Li-Cl ion pairs have a pronounced cage dynamics that remains noticeably strong even at high temperatures. Even though the Onsager coefficients, which are the time integrals of the diffusion flux correlation functions, portray a relatively smooth variation across various compositions and temperatures, we observe a sign change and a divergent-like behavior for the MS diffusivity of the K-Li ion pair at a temperature of ˜1100 K for the eutectic composition, and at a KCl mole fraction of ˜0.49 at 1043 K. Negative MS diffusivities, while unusual, are however shown to satisfy the nonnegative entropic constraints.

Chakraborty, Brahmananda; Wang, Jin; Eapen, Jacob

2013-05-01

165

Determination of the crystal growth mechanism of KCl in ethanol?water system  

NASA Astrophysics Data System (ADS)

The mechanism of crystal growth of KCl in ethanol-water system is studied by Nielsen's map-model, and the growth rate is estimated by the induction time (nucleation rate, growth rate) function in a salting-out crystallization system. In the experiments, the induction time and the particle size distribution of the final product were measured, and the solid-liquid interfacial tension was calculated from the induction period data. The map of rate control of crystal-growth for the KCl-ethanol-water salting out system was constructed by taking into consideration that the liquid-vapour interfacial tension varied with the variation of the ethanol concentration, and, as a consequence, the solid-liquid interfacial tension varied as well. As a result, diffusion controlled crystal growth was obtained as a rate-determining step for supersaturation ratios 0.01<0.45. For determining the crystal growth rate, the nucleation rate was estimated from the experimental average particle number and induction period, applying the assumption that all nuclei were born during the induction period. The results, obtained by using linear and non-linear regressions, have appeared to be in good agreement with the data published in the literature.

Liszi, I.; Hasznosné-Nezdei, M.; Lakatos, B. G.; Sapundzhiev, Ts. J.; Popov, R. G.

1999-03-01

166

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

SciTech Connect

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.

Chen, Ken Shuang

2009-04-01

167

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

NASA Astrophysics Data System (ADS)

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.

Caulder, Stanley; Mackey, Joseph; Wilkinson, John

2009-06-01

168

Investigation of the relation between microstructural parameters and magnetic properties of KClO 3-doped YBCO superconductors  

NASA Astrophysics Data System (ADS)

The influence of KClO 3 addition on the microstructure and magnetic properties of YBCO were investigated. The AC complex susceptibility ? AC = ?? - i?? was recorded as a function of temperature and concentration of KClO 3 addition at various AC magnetic fields up to 2 mT. DC magnetization as function of temperature was measured by means of a SQUID magnetometer in field-cooled cooling and field-cooled warming (FCW) modes in magnetic fields in the range 0 ? ? 0Ha ? 7T.

Koblischka-Veneva, Anjela; Koblischka, Michael R.; Murakami, Masato

2000-11-01

169

Inhibitory effects of nitrilotris(methylenephosphonic acid) on cathodic reactions of steels in saturated Ca(OH) 2 solutions  

Microsoft Academic Search

Severe localized corrosion of buried steel pipes is likely to occur near the sites where pipes penetrate or contact concrete structures. This type of corrosion is caused by the more anodic potential of steel in concrete than in soil. Since the corrosion is induced by cathodic reactions on steel surfaces in concrete accompanied by anodic reactions (i.e., corrosion) on those

Norio Nakayama

2000-01-01

170

Nanostructured modification of mineral particle surfaces in Ca(OH) 2–H 2O–CO 2 system  

Microsoft Academic Search

Traditionally pulverized particulates of raw minerals, such as ground calcium carbonate (GCC), wollastonite and dolomite, are usually of smooth\\/flat surface and pointed edges angles which have disadvantageous effects on the mechanical properties of composite polymer materials filled with the powders. On the other hand, dispersion of nanoscaled calcuim carbonate powders can not be easily achieved when filled in organic polymer,

Y. F. Yang; G. S. Gai; S. M. Fan; X. Y. Hao; Q. R. Chen

2005-01-01

171

Thermal decomposition of Ca(Oh) 2 from acetylene manufacturing: a route to supports for methane oxidative coupling catalysts  

Microsoft Academic Search

Oxidative coupling of methane (OCM) is one of the most widely studied catalytic reactions nowadays, due mainly to the large amounts of natural gas whose use to produce heavier hydrocarbons and alcohols would increase its profitability [1-5]. The reaction is generally performed using basic catalysts, supported on MgO or CaO, doped with alkaline or rare-earth cations [6-10]. In this letter,

M. J. Hologado; V. Rives; S. San Román

1992-01-01

172

Pyrotechnic Output of TiH/sub X//KClO sub 4 Actuators. IV. Modelling of TiH/sub X//KClO sub 4 Actuator Pyrotechnic Output.  

National Technical Information Service (NTIS)

Pyrotechnic output generated by TiH/sub x//KClO sub 4 loaded actuators has been modelled through an analysis of the applicable forces and utilization of relevant VISAR and load cell data. The assumption of a linearly decreasing force--time relationship yi...

M. L. Lieberman S. E. Benzley

1979-01-01

173

Epitaxial films of BSCCO grown from liquid KCl solutions onto several substrates  

SciTech Connect

In this paper, using liquid phase epitaxy growth technique (LPE), the authors obtain truly epitaxial BSCCO films on SrTiO{sub 3} and LaGaO{sub 3} substrates. Single-phase samples have been grown both of the 2201 and of the 2212 phase. The growth liquid is a saturated solution of the BSCCO constituent oxides in KCl, and a suitable thermal gradient allows chemical transport from the solute to the substrate. The films have mirror-like surface, small mosaic spread and thickness up to a few microns. The as-grown samples are fully superconducting. The typical resistance vs temperature curve shows a metallic behavior down to about 80 K, followed by a narrow superconducting transition, with zero resistance reached at about 75 K.

Balestrino, G. (Dipartimento di Fisica, Universita di Salerno, I-84100 Salerno (IT)); Fogtietli, V.; Marinelli, M. (I.E.S.S.-C.N.R., via Ciento Romano 42, I-00156 Roma (IT)); Milani, E.; Paoletti, A.; Paroli, P. (Dipartimento di Ingegneria Meccanica, II Universita di Roma via O. Raimodo 8, I-00173 Roma (IT))

1991-03-01

174

Modulation of neuronal activity by phosphorylation of the K-Cl cotransporter KCC2.  

PubMed

The K-Cl cotransporter KCC2 establishes the low intraneuronal Cl- levels required for the hyperpolarizing inhibitory postsynaptic potentials mediated by ionotropic ?-aminobutyric acid receptors (GABAARs) and glycine receptors (GlyRs). Decreased KCC2-mediated Cl- extrusion and impaired hyperpolarizing GABAAR- and/or GlyR-mediated currents have been implicated in epilepsy, neuropathic pain, and spasticity. Recent evidence suggests that the intrinsic ion transport rate, cell surface stability, and plasmalemmal trafficking of KCC2 are rapidly and reversibly modulated by the (de)phosphorylation of critical serine, threonine, and tyrosine residues in the C terminus of this protein. Alterations in KCC2 phosphorylation have been associated with impaired KCC2 function in several neurological diseases. Targeting KCC2 phosphorylation directly or indirectly via upstream regulatory kinases might be a novel strategy to modulate GABA- and/or glycinergic signaling for therapeutic benefit. PMID:24139641

Kahle, Kristopher T; Deeb, Tarek Z; Puskarjov, Martin; Silayeva, Liliya; Liang, Bo; Kaila, Kai; Moss, Stephen J

2013-12-01

175

Thermodynamic properties of iron and nickel chloride solutions in molten LiCl-KCl  

SciTech Connect

The thermodynamic properties of solutions of iron or nickel chlorides in mixed molten LiCl-KCl were determined by emf measurements of FeCl{sub 2} or NiCl{sub 2} formation cells. The concentration range examined was 0.015-2 mol %. The temperature dependence of the emf between 355 and 540{degree}C was used to calculate the enthalpy and entropy of formation of dissolved FeCl{sub 2} or NiCl{sub 2}. It was shown that, in the investigated concentration range, these solutions have a nearly ideal behavior. Simple empirical equations were derived to represent the emf of these formation cells with an accuracy of about {plus minus} 1.5 mV.

Lantelme, F.; Chemla, M. (Universite Pierre et Marie Curie, Paris (France)); Equey, J.F.; Mueller, S. (Paul Scherrer Institut, Villigen (Switzerland))

1991-01-24

176

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

PubMed Central

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).

Benisek, Artur; Dachs, Edgar

2013-01-01

177

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

SciTech Connect

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.

Yurakov, Yu. A., E-mail: ftt@phys.vsu.ru; Ryabtsev, S. V.; Chuvenkova, O. A.; Domashevskaya, E. P.; Nikitenko, A. S. [Voronezh State University (Russian Federation); Kannykin, S. V.; Kushchev, S. B., E-mail: kusheev@phis.vorstu.ru [Voronezh State Technical University (Russian Federation)

2009-01-15

178

Effects of various dopants on NaCl and KCl glow curves  

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

179

Oxygen and chlorine electrodes on semiconductive SnO 2 in molten LiCl-KCl eutectic  

Microsoft Academic Search

The oxidation of oxide (O2-) and chloride ions were studied at tin oxide electrodes in molten LiCl-KCl eutectic at 450° C using voltammetric techniques. The polarization characteristics of the oxide semiconductor electrode were compared with that of Pt in the case of the oxygen electrode and with that of glassy carbon in the case of chlorine evolution. Both electrode reactions

I. Uchida; S. Toshima

1979-01-01

180

Adsorption of NaCl and KCl on AlâOâ at 800 to 900°C  

Microsoft Academic Search

Adsorption was observed by measuring the weights of microporous alumina adsorbents as a function of time while they were exposed to varying partial pressures of NaCl and KCl in a stream of Ar. Despite the high experimental temperatures, the results exhibited the characteristics of physical adsorption. Adsorption and desorption were reversible without hysteresis. The kinetics appeared to be limited by

K. L. Luthra; O. H. Jr. LeBlanc

1984-01-01

181

Study on a recovery of rare earth oxides from a LiCl-KCl-RECl 3 system  

NASA Astrophysics Data System (ADS)

Radioactive rare earth chlorides in waste LiCl-KCl molten salts have to be separated as a stable form to minimize waste volume and to achieve stable solidification. In this work, thermal behavior of rare earth chlorides (CeCl 3, GdCl 3, NdCl 3, PrCl 3) was investigated in an oxygen condition to recover rare earth oxides from a LiCl-KCl-RECl 3 system. The rare earth chlorides in the LiCl-KCl molten salts were smoothly converted to an oxychloride form at a higher temperature than 650 °C, except for CeCl 3. CeCl 3 was totally converted to an oxide from at a higher temperature than 450 °C. The rare earth oxychlorides (GdOCl, NdOCl, PrOCl) were effectively converted to oxide forms at a higher temperature than 1100 °C. It was confirmed that rare earth oxides can be recovered from a LiCl-KCl-RECl 3 system without impurity generation.

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

2011-01-01

182

Stability of the Pyrotechnic Mixture Titanium Hydride (TiH/sub X/)/Potassium Perchlorate (KClO sub 4 ).  

National Technical Information Service (NTIS)

A study of TiH/sub x//KClO sub 4 (x = 0.1 to 1.9) has been conducted to determine the stability of the pyrotechnic formulation. The reaction kinetics were measured by monitoring water formation and chloride ion concentration in bulk, pellet, and component...

T. M. Massis P. K. Morenus R. M. Merrill

1976-01-01

183

Pyrotechnic Output of TiH/sub X/KClO sub 4 Actuators from Velocity Measurements.  

National Technical Information Service (NTIS)

The pyrotechnic output of TiH/sub x//KClO sub 4 loaded actuators has been determined from analysis of piston velocity data obtained from VISAR measurements. The effects of fuel stoichiometry, fuel/oxidizer ratio, and particle size are assessed. Computer-a...

M. L. Lieberman K. H. Haskell

1978-01-01

184

Volume changes and potential artifacts of epithelial cells of frog skin following impalement with microelectrodes filled with 3 m KCl  

Microsoft Academic Search

Summary  Cells of isolated frog skin epithelium were observed microscopically during impalement with standard microelectrodes of 5 to 20 M resistance, filled with 3m KCl. Impaled cells, as well as some neighboring cells, were seen to swell 10 to 100 sec after impalement, while the negative potential recorded by the microelectrode depolarized (open circuit conditions). Apparently, osmotic swelling of small epithelial

D. J. Nelson; J. Ehrenfeld; B. Lindemann

1978-01-01

185

Automated methods for ammonium, nitrate, and nitrite in 2 M KCl?phenylmercuric acetate extracts of soil  

Microsoft Academic Search

Automated methods for determining ammonium, nitrate, and nitrite in a single soil extract containing 2 M KCl and 5 mg\\/L phenylmercuric acetate are presented. The ammonium method is also suitable for Kjeldahl, soil and plant digests. Amino acid interferences with the ammonium method are reported. Ammonium is determined by a salicylate?isocyanurate method, while nitrite is determined by the colorimetric reaction

F. J. Adamsen; D. S. Bigelow; G. R. Scott

1985-01-01

186

Urea and KCl have differential effects on enzyme activities in liver and muscle of estivating versus nonestivating species  

Microsoft Academic Search

The effects of 300 mM urea or 300 mM KCl on the maximal activities of 25 enzymes of intermediary me- tabolism were assessed in extracts of liver and muscle from spadefoot toads (Scaphiopus couchii), leopard frogs (Rana pipiens), and rats to assess their sensitivity to these osmolytes. During estivation, toads can lose ~50% of total body water, and urea, which

Kyra J. Cowan; Kenneth B. Storey

2002-01-01

187

Sonochemical synthesis of calcium phosphate powders.  

PubMed

beta-tricalcium phosphate (beta-TCP) and biphasic calcium phosphate powders (BCP), consisting of hydroxyapatite (HA) and beta-TCP, were synthesized by thermal decomposition of precursor powders obtained from neutralization method. The precursor powders with a Ca/P molar ratio of 1.5 were prepared by adding an orthophosphoric acid (H(3)PO(4)) solution to an aqueous suspension containing calcium hydroxide (Ca(OH)(2)). Mixing was carried out by vigorous stirring and under sonochemical irradiation at 50 kHz, respectively. Glycerol and D-glucose were added to evaluate their influence on the precipitation of the resulting calcium phosphate powders. After calcination at 1000 degrees C for 3 h BCP nanopowders of various HA/beta-TCP ratio were obtained. PMID:17136604

de Campos, M; Müller, F A; Bressiani, A H A; Bressiani, J C; Greil, P

2007-05-01

188

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

NASA Astrophysics Data System (ADS)

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

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

2005-03-01

189

Thermodynamic analysis of TiH/sub x//KClO/sub 4/ combustion in a closed system  

SciTech Connect

The combustion of TiH/sub x//KClO/sub 4/ in a closed system with densities of 50 to 85 percent of the theoretical void free density is investigated. The thermodynamic properties are determined assuming equilibrium conditions using the TIGER computer program. Assuming complete combustion of the TiH/sub x//KClO/sub 4/ and a constant volume for the closed system, the calculated results indicate an equilibrium pressure that increases with the TiH/sub x//KClO/sub 4/ density. The high equilibrium pressures that were calculated suggested that accurate equations of state must be used; therefore the effect of different equations of state was investigated. As expected, the flame temperature and the concentrations of the combustion product species are not strong functions of the TiH/sub x//KClO/sub 4/ density. The calculated temperature of the gaseous products of combustion is close to the isochoric flame temperature. This is due to the fact that the heat loss from the combustion products is neglected and the system is assumed to initially have a negligible amount of gas present. The equilibrium pressure is an important parameter in determining the burning rate of TiH/sub x//KClO/sub 4/ in both the conductive and convective modes. In the conductive mode, the heat feedback from gaseous combustion products depends on the pressure and in the convective mode, both the flow of combustion products into the pores and the heat feedback are pressure dependent. 16 refs., 3 figs., 6 tabs.

Razani, A.; Shahinpoor, M.

1988-01-01

190

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

PubMed Central

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

Delpire, Eric

2013-01-01

191

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

NASA Astrophysics Data System (ADS)

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

Santhosh, S.; Prabu, S. Balasivanandha

2012-10-01

192

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium  

NASA Astrophysics Data System (ADS)

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.

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

2010-07-01

193

Vapor pressure of ZrClâ and HfClâ over melt systems KCl + AlClâ (1:1.04 mol) + ZrClâ and KCl + AlClâ (1:1.04 mol) + HfClâ  

Microsoft Academic Search

The vapor pressures of ZrClâ and HfClâ over a molten salt mixture of KCl + AlClâ (1:1.04 mol) + XClâ (X = Zr, Hf) was determined in the temperature range of 485--627 K by the transpiration technique. The compositions of ZrClâ and HfClâ in the molten salt system were chosen such that it would be useful for vapor phase separation

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

1995-01-01

194

On the formation of U Al alloys in the molten LiCl KCl eutectic  

NASA Astrophysics Data System (ADS)

U-Al alloy formation has been studied in the temperature range of 400-550 °C by electrochemical techniques in the molten LiCl-KCl eutectic. Cyclic voltammetry showed that underpotential reduction of U(III) onto solid Al occurs at a potential about 0.35 V more anodic than pure U deposition. Open circuit potential measurements, recorded after small depositions of U metal onto the Al electrode, did not allow the distinction between potentials associated with UAl x alloys and the Al rest potential, as they were found to be practically identical. As a consequence, a spontaneous chemical reaction between dissolved UCl 3 and Al is thermodynamically possible and was experimentally observed. Galvanostatic electrolyses were carried out both on Al rods and Al plates. Stable and dense U-Al deposits were obtained with high faradic yields, and the possibility to load the whole bulk of a thin Al plate was demonstrated. The analyses (by SEM-EDX and XRD) of the deposits indicated the formation of different intermetallic phases (UAl 2, UAl 3 and UAl 4) depending on the experimental conditions.

Cassayre, L.; Caravaca, C.; Jardin, R.; Malmbeck, R.; Masset, P.; Mendes, E.; Serp, J.; Soucek, P.; Glatz, J.-P.

2008-08-01

195

Separation of plutonium from lanthanum by electrolysis in LiCl KCl onto molten bismuth electrode  

NASA Astrophysics Data System (ADS)

This work presents a study on the electroseparation of plutonium from lanthanum using molten bismuth electrodes in LiCl-KCl eutectic at 733 K. The reduction potentials of Pu 3+ and La 3+ ions were measured on a Bi thin film electrode using cyclic voltammetry (CV). A difference between the peak potentials for the formation of PuBi 2 and LaBi 2 of approximately 100 mV was found. Separation tests were then carried out using different current densities and salt phase compositions between a plutonium rod anode and an unstirred molten Bi cathode in order to evaluate the efficiency of an electrolytic separation process. At a current density of 12 mA/cm 2/wt% (Pu 3+), only Pu 3+ ions are reduced into the molten Bi electrode, leaving La 3+ ions in the salt melt. Similar results were found at two different Pu/La concentration ratios ([Pu]/[La] = 4 and 10). At a current density of 26 mA/cm 2/wt% (Pu 3+), co-reduction of Pu and La was observed as expected by the large negative potential of the Bi cathode during the separation test.

Serp, J.; Lefebvre, P.; Malmbeck, R.; Rebizant, J.; Vallet, P.; Glatz, J.-P.

2005-04-01

196

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

SciTech Connect

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.

Engmann, J.; Blanch, H.W.; Prausnitz, J.M. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering]|[Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.

1997-03-01

197

Thermal ignition of TiH/sub 1. 68/KClO/sub 4/  

SciTech Connect

Many explosive components are ignited using the thermal pulse produced by passing a low current through a small metal bridgewire which has explosive powder pressed against it. A quantitative description to aid the component designer of these so-called hot-wire devices that includes ignition and powder burn does not yet exist. Therefore, we began to carefully examine ignition as a function of the explosive powder type and those physical parameters that the component engineer can adjust in the development of a new device. Using a 300-watt, cw, Nd-YAG laser, we rapidly heated a test fixture into which the pyrotechnic powder, TiH/sub 1.68/KClO/sub 4/, was pressed. We measured the time to ignition as a function of the applied heat flux, the mass of the explosive powder and powder density. The experimental scheme was statistically designed and the data analyzed by a multilinear regression model. For lower laser power values the ignition times were (almost) independent of powder mass. However, for high laser power values (greater than 120 watts) the ignition time vs powder mass regression surface had a maximum at 22.5 mg of powder (near the mid-range of weights tested). 10 refs., 4 figs., 2 tabs.

Bickes, R.W. Jr.

1986-01-01

198

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

PubMed

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

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

2004-10-01

199

Shock sensitivity of TiH/sub 0. 65/KClO/sub 4/  

SciTech Connect

The pyrotechnic TiH/sub 0.65/KClO/sub 4/ (THKP) is shock initiated in a through-bulkhead actuator (TBA) manufactured at UniDynamics. In the testing of various lots of THKP, we observed an apparent lot-to-lot variability in the shock sensitivities of the powders. The shock sensitivity for each powder lot was obtained by firing fifty TBA units each specially machined with a different bulkhead thickness. These powder lot qualification tests were both expensive and time consuming. For those reasons, we developed a new sensitivity test that is less complicated, inexpensive and consumes less THKP powder. In addition, it has the advantage that we can now easily vary several powder parameters such as density, powder preparation and condition, powder mass and the diameter of the powder column. Our new test method consists of simultaneously shocking 20 simulated TBA units in a so-called shock board. The shock board contains the simulated TBAs around its periphery; the TBA simulators can have various bulkhead thicknesses and are easy to machine. The simulators are mounted at the ends of EXTEX tracks that are all fired at the same time by a detonator located at the center of the board. After firing the assembly, the units are checked for function and the data analyzed using the ASENT computer program. 8 refs., 3 figs., 1 tab.

Headley, P.S.; Bickes, R.W. Jr.

1986-01-01

200

Activity coefficients of actinide and rare-earth chlorides in molten LiCl/KCl eutectic salt  

SciTech Connect

Using a numerical Gibbs free-energy minimization technique, the activity coefficients of actinide and rare-earth chlorides in molten LiCl/KCl eutectic at 450 C have been calculated. Laboratory tests of an electrochemical process for separating actinide metals from rare-earth metals in LiCl/KCl solvent at 450 C provided experimental concentration and cathode potential data. The generalized expansion by Wohl was used to express the concentration dependence of the excess Gibbs free energy. The activity coefficients were expressed in terms of the Wohl volume and interaction energy parameters. The Wohl parameters for the activity coefficient expansions were obtained by minimizing the total Gibbs free energy expressed in terms of the experimental mole fractions. This thermodynamic model will be valuable for process design and scale-up calculations.

Bechtel, T.B.; Storvick, T.S. [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemical Engineering] [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemical Engineering

1999-04-01

201

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

202

Interaction between SiO2 and a KF-KCl-K2SiF6 Melt.  

PubMed

The solubility mechanism of silica in a fluoride-chloride melt has been determined in situ using Raman spectroscopy. The spectroscopy data revealed that the silica solubility process involved Si-O bond breakage and Si-F bond formation. The process results in the formation of silicate complexes, fluorine-bearing silicate complexes, and silicon tetrafluoride in the melt. Mass spectrometry of the vapor phase over the KF-KCl-K2SiF6 and KF-KCl-K2SiF6-SiO2 melts and differential scanning calorimetry coupled with thermal gravimetric analysis of these melts were performed to verify the silica solubility mechanism. PMID:24428731

Zaykov, Yurii P; Isakov, Andrey V; Zakiryanova, Irina D; Reznitskikh, Olga G; Chemezov, Oleg V; Redkin, Alexander A

2014-02-13

203

ExoMol molecular line lists V: the ro-vibrational spectra of NaCl and KCl  

NASA Astrophysics Data System (ADS)

Accurate rotation-vibration line lists for two molecules, NaCl and KCl, in their ground electronic states are presented. These line lists are suitable for temperatures relevant to exoplanetary atmospheres and cool stars (up to 3000 K). Isotopologues 23Na35Cl, 23Na37Cl, 39K35Cl, 39K37Cl, 41K35Cl and 41K37Cl are considered. Laboratory data were used to refine ab initio potential energy curves in order to compute accurate ro-vibrational energy levels. Einstein A coefficients are generated using newly determined ab initio dipole moment curves calculated using the CCSD(T) method. New Dunham Yij constants for KCl are generated by a re-analysis of a published Fourier transform infrared emission spectra. Partition functions plus full line lists of ro-vibration transitions are made available in an electronic form as supplementary data to this paper and at www.exomol.com.

Barton, Emma J.; Chiu, Christopher; Golpayegani, Shirin; Yurchenko, Sergei N.; Tennyson, Jonathan; Frohman, Daniel J.; Bernath, Peter F.

2014-08-01

204

Thermodynamic properties of trivalent lanthanide and actinide ions in molten mixtures of LiCl and KCl  

NASA Astrophysics Data System (ADS)

The thermodynamic stability of Ln(III) (Ln: La, Ce, Pr, Tb, and Er) and U(III) complexes in LiCl-KCl system at 923 K was studied by electrochemical techniques. The Gibbs free energy change of the Ln3+/Ln0 and U3+/U0 redox reactions, ?G3/0?', was investigated under various mole fraction of KCl, ?K = 0-0.65. In general, ?G3/0?' increased linearly with the decrease of ?K due to the distortion of octahedral symmetry of LnCl63- and UCl63-, but a few exceptions were found for lighter Ln elements, e.g., La and Ce, at smaller ?K of 0-0.2. The discrepancy suggests an increase of the number of Cl- ions around La3+ and Ce3+.

Fukasawa, Kazuhito; Uehara, Akihiro; Nagai, Takayuki; Sato, Nobuaki; Fujii, Toshiyuki; Yamana, Hajimu

2012-05-01

205

Examination of reference potentials for the molten Kx(KCl)1-x system by the Percus-Yevick approximation  

Microsoft Academic Search

The structure of the molten Kx(KCl)1-x system at the metal rich side has been investigated by using three kinds of reference potential, which are the simplified versions of the model pair potentials proposed previously, within the framework of the Percus-Yevick (PY) approximation. It is shown that the sharp rise of the total structure factor at low momentum transfers, which is

S. Naito; S. Fukase; R. Takagi; K. Kawamura

1987-01-01

206

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

Microsoft Academic Search

The burning behavior of titanium subhydride potassium perchlorate (TiH{sub 1.65}\\/KClOâ) is currently under investigation. The research is presently aimed at studying the dynamic compaction of the material as a confined cylindrical charge of the pyrotechnic burns. Flash radiography equipment, optical fibers, and piezoelectric pressure transducers are used to study this phenomenon. The length to diameter ratio of the test charge

S. L. Hingorani-Norenberg; A. Razani; M. Shahinpoor

1990-01-01

207

Electrochemical formation of Mg–Li alloys at solid magnesium electrode from LiCl–KCl melts  

Microsoft Academic Search

This work presents a study on electrochemical formation of Mg–Li alloys on solid magnesium electrode in a molten LiCl–KCl (50:50, wt.%) system at 753K. Cyclic voltammetry and open circuit chronopotentiometry were employed to investigate the electrode reaction. For an Mg electrode, the electroreduction of Li(I) takes place at more positive potential values than at the inert W electrode indicating the

Yong De Yan; Mi Lin Zhang; Wei Han; Dian Xue Cao; Yi Yuan; Yun Xue; Zeng Chen

2008-01-01

208

Interference by magnesium in the determination of nitrate in 2 M KCl extracts of soil by steam distillation  

Microsoft Academic Search

Steam distillation of 2 M KCl extracts of soil showed low recovery of NO3?N when compared with an automated method for NO3?N determination. The low recoveries were more pronounced in extracts where a soil:solution ratio of 1:2.5 had been used. In extracts where the Mg content was in excess of 0.02 M Mg, recoveries of added NO3?N could be as

E. K. Best; E. T. Craswell

1985-01-01

209

Mechanism of Activity-Dependent Downregulation of the Neuron-Specific K-Cl Cotransporter KCC2  

Microsoft Academic Search

GABA-mediated fast-hyperpolarizing inhibition depends on extrusion of chloride by the neuron-specific K-Cl cotransporter, KCC2. Here we show that sustained interictal-like activity in hippocampal slices downregulates KCC2 mRNA and protein expression in CA1 pyrami- dal neurons, which leads to a reduced capacity for neuronal Cl extrusion. This effect is mediated by endogenous BDNF acting on tyrosine receptor kinase B (TrkB), with

Claudio Rivera; Juha Voipio; Judith Thomas-Crusells; Hong Li; Zsuzsa Emri; Sampsa Sipila; John A. Payne; Liliana Minichiello; Mart Saarma; Kai Kaila

2004-01-01

210

The effects of temperature and different precursors in the synthesis of nano spinel in KCl molten salt  

Microsoft Academic Search

Nano-particles of MgAl2O4 were successfully synthesized at 850°C using the molten-salt method, and the effects of processing parameters, such as the amount and type of precursor and temperature on the crystallization of MgAl2O4, were investigated. Spinel nano powders were synthesized by heating stoichiometric compositions of different MgO- and Al2O3-bearing precursors in potassium chlorides (KCl). The phase formation, morphology and purity

Y. Safaei-Naeini; M. Aminzare; F. Golestani-Fard

211

Vibrational-rotational dependence of molecular properties. Electric field gradients for HCl, LiCl, NaCl and KCl  

Microsoft Academic Search

The vibrational-rotational dependence of the nuclear quadrupole coupling constant (NQCC) for the isotopes 2H, 7Li, 23Na, 39K, and 35Cl is analysed in detail for the diatomic Group 1 chlorides HCl, LiCl, NaCl and KCl. The potential energy curves were calculated pointwise by using coupled cluster techniques. The electric field gradients (EFGs) and dipole moments were obtained analytically from a QCISD

Michael Seth; Markus Pernpointner; Graham A. Bowmaker; Peter Schwerdtfeger

1999-01-01

212

Shock-induced melting of a KCl:LiCl eutectic powder as determined from electrochemical response measurements  

Microsoft Academic Search

Shock-induced melting of powder compacts of a eutectic of KCl and LiCl has been investigated in an electrochemical cell in which the eutectic serves as the electrolyte with an anode of a lithium-silicon alloy and a cathode with a mixture of FeS2, the eutectic and silicon dioxide. The cell remains inactive into low impedance electrical loads until the powder is

R. A. Graham; B. Morosin; D. M. Bush

1987-01-01

213

Stability of the pyrotechnic mixture titanium hydride (TiH\\/sub x\\/)\\/potassium perchlorate (KClO)  

Microsoft Academic Search

A study of TiH\\/sub x\\/\\/KClO (x = 0.1 to 1.9) has been conducted to determine the stability of the pyrotechnic formulation. The reaction kinetics were measured by monitoring water formation and chloride ion concentration in bulk, pellet, and component geometry. It was found that the stability of the pyrotechnic mix increased as the hydrogen content in the titanium hydride was

T. M. Massis; P. K. Morenus; R. M. Merrill

1976-01-01

214

Electromotive force responses of Cl[sub 2] gas sensor using BaCl[sub 2]-KCl solid electrolyte  

SciTech Connect

Chlorine is the most important halogen in industrial production. Chlorine exhaust gas has become a serious problem with regard to air pollution and acid rain in recent years. Solid electrolyte-type gas sensors are superior for SO[sub x] or CO[sub 2] detection because of their rapid response. A Cl[sub 2] gas sensor using BaCl[sub 2]-KCl solid electrolyte was investigated. The conductivity was greatly enhanced by KCl doping of the (1 [minus] x)BaCl[sub 2][minus]x KCl system, and a maximum conductivity of 5.6 [times] 10[sup [minus]5]S [times] cm[sup [minus]1] at 573 K was obtained for x = 0.02. The sensor probe was prepared by a melting method at 1,373 K. The electromotive force (EMF) measurement with the Cl[sub 2] gas sensor using the 0.97BaCl[sub 2]-0.03KCl solid electrolyte was performed with an Ag-AgCl solid reference electrode and an RuO[sub 2] measuring electrode. Good agreement between the measured and the calculated EMF values was obtained for Cl[sub 2] gas concentrations from 50 to 10,000 ppm at 623 K. The EMF response time with a change in Cl[sub 2] concentration is ca. 1 min for above 100 ppm and 2 to 5 min for lower concentrations. The measured EMF was not influenced by O[sub 2] or CO[sub 2] gas concentration. This sensor probe was very stable in the presence of water vapor at 623 K during a 90 day test period.

Aono, Hiromichi; Sugimoto, Eisuke (Niihama National Coll. of Technology, Ehime (Japan). Dept. of Industrial Chemistry); Mori, Yoshiaki; Okajima, Yasuhiro (Sumitomo Metal Mining Co., Ltd., Ehime (Japan). Niihama Research Lab.)

1993-11-01

215

Luminescent characteristics of pure and Ce doped K2LaCl5 phase in KCl host  

NASA Astrophysics Data System (ADS)

The formation of Ce3+ doped K2LaCl5 microphase has been revealed for the KCl-LaCl3-CeCl3 system. Luminescent characteristics of pure and Ce3+ doped K2LaCl5 microcrystals, embedded in KCl matrix, are studied in comparison with those of bulk K2LaCl5:Ce(0.1%) crystal. For both the micro- and bulk K2LaCl5:Ce crystals the bands peaked at 344 and 373 nm are attributed to Ce3+ emission revealing a 24 ns time constant for the main decay component upon the excitation within the Ce3+ f-d absorption range. The method elaborated for the synthesis of the activated K2LaCl5 microphase in the KCl-LaCl3-CeCl3 system provides the possibility of producing large-size homogeneous scintillation elements possessing efficient emission of rare earth doped A2LaX5 micro- and nano-phases embedded in AX matrices (A = Cs, K, Rb; X = F, Cl, Br, I).

Voloshinovskii, A.; Stryganyuk, G.; Zimmerer, G.; Rodnyi, P.; Antonyak, O.; Myagkota, S.; Savchyn, P.

2005-07-01

216

Exploring Io's Atmospheric Composition with APEX: First Measurement of 34SO2 and Tentative Detection of KCl  

NASA Astrophysics Data System (ADS)

The composition of Io's tenuous atmosphere is poorly constrained. Only the major species SO2 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, S2O) and isotopes (34SO2). 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 SO2 and derive a range of 4 × 10-4-8 × 10-3. We do not detect SiO or S2O and present new upper limits on their abundances. We also present the first measurement of the 34S/32S 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 SO2 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 SO2 in volcanic plumes, both the tentative KCl detection and SiO upper limit are compatible with a purely volcanic origin for these species.

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

2013-10-01

217

Diffusional creep of multicomponent systems. Progress report, February 1, 1980-January 31, 1981. [Dislocation-crack interactions; photoplastic and electroplastic effects in KCl  

SciTech Connect

Topics for which significant results are reported include dislocation-crack interactions, impression creep of Al polycrystals, and photoplastic and electroplastic effects in additively colored KCl. 9 figures. (DLC)

Li, J.C.M.

1981-01-01

218

Role of Nitrite, a Nitric Oxide Derivative, in K-Cl Cotransport Activation of Low-Potassium Sheep Red Blood Cells  

Microsoft Academic Search

.   K-Cl cotransport (COT) is the coupled movement of K and Cl, present in most cells, associated with regulatory volume decrease,\\u000a susceptible to oxidation and functionally overexpressed in sickle cell anemia. The aim of this study was to characterize the\\u000a effect of the oxidant nitrite (NO2\\u000a \\u000a ?) on K-Cl COT. NO2\\u000a \\u000a ? is a stable metabolic end product of the

N. C. Adragna; P. K. Lauf

1998-01-01

219

Influence of surface charge field on the electron impact fragmentation pattern of KCl molecules in the free surface vaporization of single crystals  

Microsoft Academic Search

A mass-spectrometric method was used to investigate the temperature dependence of the electron impact fragmentation pattern of KCl molecules [ion current ratio I(K+)\\/I(KCl+)] vaporizing from a free surface of a potassium chloride single crystal. In the temperature range 766–945 K a very good correlation is observed between the variation in fragmentation pattern with temperature and the pattern of the curve

M. F. Butman; A. A. Smirnov; L. S. Kudin; Z. A. Munir

2000-01-01

220

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

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

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

2014-02-01

221

Further studies on the partial double Donnan. Is isosmotic KCl solution isotonic with cells of respiratory trees of the holothurian Isostichopus badionotus Selenka?  

PubMed

As potassium, chloride and water traverse cell membranes, the cells of stenohaline marine invertebrates should swell if exposed to sea water mixed with an isosmotic KCl solution as they do when exposed to sea water diluted with water. To test this hypothesis respiratory tree fragments of the holothurian Isostichopus badionotus were exposed to five isosmotic media prepared by mixing artificial sodium sea water with isosmotic (611 mmol/l) KCl solution to obtain 100, 83, 71, 60 and 50% sea water, with and without 2 mmol/l ouabain. For comparison, respiratory tree fragments were incubated in sea water diluted to the same concentrations with distilled water, with and without ouabain. Cell water contents and potassium and sodium concentrations were unaffected by KCl-dilution or ouabain in isosmotic KCl-sea water mixtures. In tissues exposed to H(2)O-diluted sea water, cell water increased osmometrically and potassium, sodium and chloride concentrations decreased with dilution; ouabain caused a decrease in potasium and an increase in sodium but no effect on chloride concentrations. The isotonicity of the isosmotic KCl solution cannot be adscribed to impermeability of the cell membrane to KCl as both ions easily traverse the cell membrane. Rather, operationally immobilized extracellular sodium ions, which electrostatically hold back anions and consequently water, together with the lack of a cellward electrochemical gradient for potassium, resulting from membrane depolarization caused by high external potassium concentration, would explain the isotonicity of isosmotic KCl solution. The high external potassium concentration also antagonizes the inhibitory effect of ouabain on the Na(+)/K(+) ATPase responsible for sodium and potassium active transport. PMID:10742500

Herrera; Herrera; López

2000-05-01

222

Magnesium and ATP dependence of K-Cl co-transport in low K+ sheep red blood cells.  

PubMed Central

1. In low K+ (LK) sheep red blood cells, depletion of adenosine triphosphate (ATP) by glycolysis inhibition induced specific effects on ouabain-resistant Cl(-)-dependent K+ transport (K-Cl co-transport), depending on the osmolarity: stimulation in isosmotic while inhibition in hyposmotic solutions. However, these effects depended upon the presence of internal Mg2+. 2. In LK sheep red blood cells, ATP constituted nearly 90% of the Mg2+ buffering capacity. As no significant reduction of total Mg2+ was observed after ATP depletion, the overall internal Mg2+ in ATP-depleted cells exists in the free form. 3. The dependence of K+ efflux on internal Mg2+ was also directly related to the presence of ATP. In control cells, Mg2+ constituted an endogenous inhibitor, inducing a 70% inhibition of K-Cl fluxes but only 30% in ATP-depleted cells. The Cl(-)-insensitive component of K+ efflux was unaffected by the divalent cation. 4. After Mg2+ removal, the rate of K+ efflux was significantly increased at all osmolarities, between 240 mosM (swollen cells) and 440 mosM (shrunken cells). Hence, Mg(2+)-depleted LK sheep red cells lose volume sensitivity of K-Cl co-transport. 5. Internal K+ or Cl- were not required for the Mg2+ inhibition, and Mg2+ did not interfere with the internal binding sites for Cl- or K+. Hence, the sites for Mg2+ or MgATP, and for K+ and Cl- are independent of each other.

Delpire, E; Lauf, P K

1991-01-01

223

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

PubMed Central

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.

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

1989-01-01

224

Ideal Supercapacitor Behavior of Amorphous V2O5.nH2O in Potassium Chloride (KCl) Aqueous Solution  

Microsoft Academic Search

Amorphous a-V2O5.nH2O in mild KCl aqueous electrolyte proves to be an excellent electrode for a faradaic electrochemical capacitor. Cyclic voltammograms versus SCE give ideal capacitor behavior between 0.0 and +0.8 V at pH 6.67 and between -0.2 and +0.8 V at pH 2.32 with, respectively, a constant specific capacitance over 100 cycles of ca. 350 and 290 F\\/g, respectively. On

Hee Y. Lee; J. B. Goodenough

1999-01-01

225

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

NASA Astrophysics Data System (ADS)

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

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

226

Growth and X-ray studies of (NaCl)x(KCl)y-x(KBr)1-y single crystals  

NASA Astrophysics Data System (ADS)

Ternary mixed crystals of NaCl, KCl and KBr were grown by the melt method for the first time. Densities and refractive indices of all the grown crystals were determined and also used for the estimation of the bulk composition in the crystal. Lattice parameters and thermal parameters like Debye Waller factor, mean square amplitude of vibration, Debye temperature and Debye frequency were determined from the X-ray powder diffraction data. The observed lattice parameters showed the existence of two phases in crystals with NaCl content greater than 0.1 mole fraction. The thermal parameters show a highly non-linear composition dependence. The results are reported.

Jayakumari, K.; Mahadevan, C.

2005-10-01

227

Plant growth and responses of antioxidants of Chenopodium album to long-term NaCl and KCl stress  

Microsoft Academic Search

The effects of long-term NaCl and KCl treatment on plant growth and antioxidative responses were investigated in Chenopodium album, a salt-resistant species widely distributed in semi-arid and light-saline areas of Xinjiang, China. Growth parameters [plant\\u000a height, branch number, leaf morphology and chlorophyll (Chl) content], the level of oxidative stress [superoxide anion radical\\u000a (O2\\u000a ?), hydrogen peroxide (H2O2) and malondialdehyde (MDA)

Shixiang Yao; Shasha Chen; Dongsheng Xu; Haiyan Lan

2010-01-01

228

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

SciTech Connect

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.

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

2013-09-09

229

Effect of KCl on melting of the Mg2SiO4-MgSiO3-H2O system at 5 GPa  

NASA Astrophysics Data System (ADS)

Chlorine has been found as a major constituent of fluid inclusions in fibrous diamonds (Navon et al., 1988) and has been interpreted to associate with K to form a KCl-bearing brine (e.g., Klein-BenDavid et al., 2006). To examine the effect of such a KCl-bearing brine on the melting behavior of the Earth’s mantle, we conducted experiments in the Mg2SiO4-MgSiO3-H2O and Mg2SiO4-MgSiO3-KCl-H2O systems at 5 GPa and 1100-1700°C. In the Mg2SiO4-MgSiO3-H2O system, the temperature of the solidus is ~1230°C, and both forsterite and enstatite coexist with the liquid under supersolidus conditions. In the Mg2SiO4-MgSiO3-KCl-H2O systems with molar Cl/(Cl+H2O) ratios of 0.2, 0.4 and 0.6, the temperatures of the solidus are ~1430°C, ~1530°C and ~1580°C, respectively, and only forsterite coexists with liquid under supersolidus conditions. The increase in the temperature of the solidus demonstrates the significant effect of KCl on elevating the solidus of the Mg2SiO4-MgSiO3-H2O system by reducing the activity of H2O in the fluid. If KCl is present in the Earth’s mantle, it will prevent melting at the H2O-saturated solidus, and the KCl-bearing brine will be a robust agent for mantle metasomatism at temperatures greater than that of the H2O-saturated solidus. The change in the melting residues indicates that the incongruent melting of enstatite (enstatite = forsterite + silica-rich melt) could happen at pressures over 5 GPa in KCl-bearing systems, which needs to be verified by experiments on the MgSiO3-KCl-H2O system in future work. Klein-BenDavid, O., Richard, W. and Navon, O., 2006, TEM imaging and analysis of microinclusions in diamonds; a close look at diamond-growing fluids: American Mineralogist, v. 91, p. 353-365. Navon, O., Hutcheon, I.D., Rossman, G.R. and Wasserburg, G.J., 1988, Mantle-derived fluids in diamond micro-inclusions: Nature, v. 335, p. 784-789.

Chu, L.; Luth, R. W.; Enggist, A.

2009-12-01

230

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

PubMed

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

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

2013-01-01

231

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

USGS Publications Warehouse

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.

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

1992-01-01

232

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

SciTech Connect

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.

Bodnar, R.J.; Vityk, M.O. [Virginia Polytechnic Inst., Blacksburg, VA (United States)] [Virginia Polytechnic Inst., Blacksburg, VA (United States); Hryn, J.N. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States); Mavrogenes, J. [Australian National Univ., Canberra, ACT (Australia)] [Australian National Univ., Canberra, ACT (Australia)

1997-02-01

233

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

PubMed Central

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

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

2013-01-01

234

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

PubMed

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

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

2012-08-15

235

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

PubMed

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

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

2014-05-01

236

Influence of partial replacement of NaCl with KCl on lipid fraction of dry fermented sausages inoculated with a mixture of Lactobacillus plantarum and Staphylococcus carnosus.  

PubMed

The effect of partial replacement of NaCl (3% NaCl) with KCl (1.5% NaCl and 1% KCl) on the lipid fraction of dry fermented sausages inoculated with Lactobacillus plantarum and Staphylococcus carnosus as starter culture was analysed. The reduction in salt concentration did not affect the Micrococcaceae count. A positive effect on the intensity of lipolytic activity was observed as a consequence of the decrease in salt level. There was no decrease in the oxidative processes. The higher amounts of volatile fatty acids found suggest that the tested modification enhances some of their mechanisms of synthesis. PMID:22060589

Quintanilla, L; Ibañez, C; Cid, C; Astiasarán, I; Bello, J

1996-07-01

237

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.  

National Technical Information Service (NTIS)

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 electro...

C. E. Vallet D. E. Heatherly L. Heatherly J. Braunstein

1983-01-01

238

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

NASA Astrophysics Data System (ADS)

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

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

239

The use of membrane vesicles to study the NaCl/KCl cotransporter involved in active transepithelial chloride transport.  

PubMed

Properties of the NaCl/KCl cotransport system were investigated in isolated membranes by flux measurements and binding studies. Chloride competes with "furosemide-like loop diuretics" for its two binding sites at the cotransporter as evidenced by the decrease in piretanide sensitivity of sodium flux and inhibition of high affinity N-methylfurosemide binding by chloride in rectal gland plasma membranes. In the rectal gland lithium inhibits sodium flux but is not translocated whereas in the renal thick ascending limb (TALH) it is also transported. Ammonium is a substrate for the sodium and potassium site in the rectal gland but only for the potassium site in the TALH. The latter finding raises the possibility that part of the ammonium reabsorption in the TALH is mediated by the cotransport system as NaCl/NH4Cl cotransport. PMID:4088825

Kinne, R; Koenig, B; Hannafin, J; Kinne-Saffran, E; Scott, D M; Zierold, K

1985-01-01

240

Ceramic-coated positive current collectors for Li-Al/LiCl-KCl/FeS2 batteries  

NASA Astrophysics Data System (ADS)

Several electronically conducting ceramic and metallic coatings were investigated to determine their potential for use as current collectors in the positive electrodes of Li-Al/molten LiCl-KCl/FeS2 battery cells. Static and in-cell corrosion tests in laboratory-scale cells were performed; the static tests were considerably more severe than the in-cell tests. Chemical vapor deposited (CVD) TiC and TiN coatings on inexpensive iron-based substrates showed significant promise in both tests. Analysis of the results led to the recommendation that the coating quality and thickness, the substrate type, the coating procedure, the design of the cell components, and the electrochemical conditions be optimized to achieve maximum coating stability in long-term operation of Li-Al/FeS2 cells.

Bandyopadhyay, G.

1981-12-01

241

Shock-induced melting of a KCl:LiCl eutectic powder as determined from electrochemical response measurements  

SciTech Connect

Shock-induced melting of powder compacts of a eutectic of KCl and LiCl has been investigated in an electrochemical cell in which the eutectic serves as the electrolyte with an anode of a lithium-silicon alloy and a cathode with a mixture of FeS2, the eutectic and silicon dioxide. The cell remains inactive into low impedance electrical loads until the powder is melted either under shock pressure or upon release of pressure. Melt behavior is clearly indicated in time-resolved electrochemical voltage measurements and the degree of melt is sensitive to the starting powder density which controls the increase in temperature. The indicated electrolytic conductivity suggests that melting is not complete in either the shock or release state. Such electrochemical response measurements provide capability for direct studies of melting behavior, for determination of Gibbs potentials of reactions and their kinetics while under shock compression.

Graham, R.A.; Morosin, B.; Bush, D.M.

1987-01-01

242

Stress corrosion cracking of Ag-20Au in HCLO4, AgCLO4, and KCL solutions by surface mobility  

NASA Astrophysics Data System (ADS)

Slow, intermediate, and ultrafast strain-rate experiments were performed on Ag-20Au (atomic percent) wire samples in 1 M HC1O4, AgClO4, and KCl solutions. Intergranular stress corrosion cracking was found in all of the solutions tested. In the ultrafast strain-rate experiments, 9.6 s-1, in HC1O4 and in AgClO4 solutions, the size of the cracks proved to be a function of the electric charge circulated before straining. AgClO4 was also found to specifically induce stress corrosion cracking (SCC) in the Ag-20Au alloy. The surface mobility SCC mechanism was concluded to be the only one that accounted for all of the experimental observations made in the present work.

Duffó, Gustavo S.; Galvele, José R.

1993-02-01

243

Electronic and Ionic Interactions Analyzed throughConcentration and Charge Fluctuations in KxKCL(1-x) Mixtures  

NASA Astrophysics Data System (ADS)

A deeper insight into short, medium and long ranges behaviour of partial structure factors (PSF) measured in the rich metal domain of KxKCL(1-x) solutions as a function of composition shows up that structural changes are characterised by a non-linear perturbation of the screening properties prevailing in the pure metal liquid. Pseudopotential theory for describing the anion-conduction electron interaction, and perturbation calculations must be dropped. The correlation between long wavelength limits of PSF and thermodynamic is particularly difficult to unravel at k=0. The structural changes observed in neutron diffraction indicate that a better understanding of these correlations consists in treating the correlation between charge fluctuations and atomic concentration fluctuations.

Hily, L.; Dupuy-Philon, J.; Jal, J. F.; Chieux, P.

244

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

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

245

Influence of Tl+ activator ions on the luminescence characteristics of KCl0.5Br0.5:Eu2+ powder phosphors.  

PubMed

Photoluminescence (PL) of thallium co-doped with KCl0.5Br0.5:Eu2+ powder phosphors display emission bands at 320 and 370 nm attributable to centres involving Tl+ ions in addition to characteristic Eu2+ emission around 420 nm. Additional PL excitation and emission bandS observed around 260 and 380 nm, respectively, were observed in the double-doped KCl0.5Br0.5:Eu2+, Tl+ powder phosphors and are attributed to complex centres involving Tl+ and Eu2+ ions. The enhancement observed in the intensity of Eu2+ emission around 420 nm with the addition of TlBr in KCl0.5Br0.5:Eu2+ powder phosphors is attributed to the energy transfer from Tl+ --> Eu2+ ions. Photostimulated luminescence (PSL) studies of gamma-irradiated KCl0.5Br0.5:Eu2+, Tl+ mixed phosphors are reported and a tentative PSL mechanism in the phosphors has been suggested. PMID:19291812

Nagarajan, S; Sudarkodi, R

2009-01-01

246

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

NASA Astrophysics Data System (ADS)

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

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

247

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

PubMed

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. PMID:20722906

Ayyash, Mutamed M; Shah, Nagendra P

2010-08-01

248

Femtosecond Fiber Laser Pulses Amplified by a KCl:Tl+ Color-Center Amplifier for Continuum Generation in the 1.5-micrometers Region.  

National Technical Information Service (NTIS)

A diode pumped stretched pulse additive pulse mode locked Er-doped fiber laser is used to seed a KCl:Tl+ color center amplifier crystal. The initial 1-nj chirped pulses are double passed through the amplifier, which is pumped by a 1-kHz Q switched Nd:YAG ...

G. Lenz W. Gellermann D. J. Dougherty K. Tamura E. P. Ippen

1996-01-01

249

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

SciTech Connect

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

Kassman, Haakan [Vattenfall Power Consultant AB, Nykoeping (Sweden); Chalmers University of Technology, Department of Energy and Environment, Division of Energy Technology, Gothenburg (Sweden); Baefver, Linda [Technical Research Institute of Sweden, Energy Technology, Boraas (Sweden); Aamand, Lars-Erik [Chalmers University of Technology, Department of Energy and Environment, Division of Energy Technology, Gothenburg (Sweden)

2010-09-15

250

The effects of perfusion rate and NG-nitro-L-arginine methyl ester on cirazoline- and KCl-induced responses in the perfused mesenteric arterial bed of rats.  

PubMed Central

1. The purpose of this study was to characterize the effect of NG-nitro-L-arginine methyl ester (L-NAME) on the perfusion rate/pressure relations, and on the pressor responses induced to cirazoline and KCl in isolated, perfused mesenteric arterial beds from normotensive and spontaneously hypertensive rats. 2. The basal perfusion pressure of arterial beds perfused with either physiological salt solution (PSS) or PSS containing 1% polyvinylpyrrolidone increased as the perfusion rate increased. L-NAME, in concentrations up to 100 microM, failed to alter the basal pressure regardless of the perfusion rate and viscosity; however, at 5 microM, it potentiated cirazoline-induced vasoconstriction at each of the perfusion rates. 3. L-NAME but not D-NAME caused a leftward shift of cirazoline concentration-response curves with a marked increase in the maximal response. The potentiating action of L-NAME was abolished in arterial beds perfused with a Ca(2+)-free physiological salt solution and also in beds denuded of endothelium by an infusion of distilled water for 5 min. 4. In endothelium-intact and -denuded preparations, L-NAME potentiated KCl pressor responses; the endothelium-independent potentiation of KCl pressor activity was stereospecific, time-independent and was not prevented by the presence of dexamethasone (0.5 microM) in the perfusion medium. However, L-NAME failed to potentiate vasoconstriction obtained to KCl in arterial beds denervated by cold storage (4-5 degrees C) for 2 days. 5. The absence of K+ in the perfusate did not inhibit the ability of L-NAME to potentiate alpha-adrenoceptor-mediated pressor responses, and nor did L-NAME inhibit KCl-induced vasodilatation in preconstricted arteries. It was thus concluded that L-NAME does not affect Na+/K(+)-ATPase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adeagbo, A. S.; Tabrizchi, R.; Triggle, C. R.

1994-01-01

251

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

SciTech Connect

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.

Hansel, Rachael A.; Xiao, Zhiyan; Hu, Yanle; Green, Olga; Yang, Deshan; Harold Li, H. [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)] [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

2013-09-15

252

Composition of steam in the system NaCl-KCl-H2O-quartz at 600??C  

USGS Publications Warehouse

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

Fournier, R. O.; Thompson, J. M.

1993-01-01

253

Experimental study of muscovite stability in pure H 2O and 1 molal KCl-HCl solutions  

NASA Astrophysics Data System (ADS)

The following reactions have been reinvestigated in order to resolve conflicting evidence regarding tetrahedral Al/Si disorder in muscovite, KAl 2(AlSi 3)O 10(OH) 2: muscovite + quartz = andalusite + sanidine + H 2O ; muscovite = corundum + sanidine + H 2O ; muscovite + H + = 1.5 andalusite + 1.5 quartz + 1.5 H 2O + K ; 1.5 sanidine + H + = 0.5 muscovite + 3 quartz + K + Results for the first reaction in the range 1.0-3.0 kbar and second reaction in the range 1.0-6.0 kbar, together with data on the compositions of 1 molal HCl-KCl solutions limited by the third and fourth reactions at 400-500°C, 1 kbar favor total tetrahedral Al/Si disorder in muscovite, but this conclusion applies only to synthetic muscovite grown under relatively low-pressure conditions. The stable assemblage for the first and second reactions were based on growth and dissolution textures of muscovite observed with an SEM. The dP/dT slopes of the dehydration boundaries are smaller than those determined by most previous work. Results for the fourth reaction are in good agreement with other recent work, but quench pH values for the third reaction are less acidic at 400°C, hence, the muscovite stability field in KCl-HCl solutions is narrower than previously determined. Recommended thermodynamic properties for synthetic muscovite are 306.40 J/mol·K and -5970.45 kJ/mol for the standard entropy, S1,298.5°(Ms), and enthalpy of formation from the elements, ?FH1,298.15°(Ms), respectively. The enthalpy of formation of muscovite is based, in part, on a revised calorimetric value for sanidine ?FH1,298.15°(Sa) = -3965.60 ± 4.1 kJ/mol. A similar contradiction regarding tetrahedral Al/Si disorder in paragonite appears to exist between structure refinements and phase equilibrium data. However, if the phase equilibrium data for the reaction paragonite = corundum + albite + H 2O are omitted, almost all other evidence is consistent with near total Al/Si disorder in paragonite.

Haselton, H. T., Jr.; Cygan, G. L.; Jenkins, D. M.

1995-02-01

254

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

PubMed

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. PMID:16424367

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

255

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

SciTech Connect

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.

Agakishiev, G.; Destefanis, M.; Gilardi, C.; Kirschner, D.; Kuehn, W.; Lange, J. S.; Metag, V.; Mishra, D.; Pechenova, O.; Spataro, S.; Spruck, B. [II.Physikalisches Institut, Justus Liebig Universitaet Giessen, D-35392 Giessen (Germany); Balanda, A.; Dybczak, A.; Michalska, B.; Otwinowski, J.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M.; Wojcik, T. [Smoluchowski Institute of Physics, Jagiellonian University of Cracow, PL-30-059 Krakow (Poland)

2010-08-15

256

Voluntary Consumption of NaCl, KCl, CaCl2, and NH4Cl Solutions by 28 Mouse Strains  

PubMed Central

Male mice from 28 inbred strains (129P3/J, A/J, AKR/J, BALB/cByJ, BUB/BnJ, C3H/HeJ, C57BL/6J, C57L/J, CAST/Ei, CBA/J, CE/J, DBA/2J, FVB/NJ, I/LnJ, KK/H1J, LP/J, NOD/LtJ, NZB/B1NJ, P/J, PL/J, RBF/DnJ, RF/J, RIIIS/J, SEA/GnJ, SJL/J, SM/J, SPRET/Ei, and SWR/J) were tested with NaCl (75–450 mM), KCl (30–300 mM), CaCl2 (3–100 mM), and NH4Cl (10–300 mM) solutions using two-bottle preference tests with water as the second choice. For each mineral, there was a wide range of strain variation in solution intakes and preferences. This variation had a substantial genetic component as assessed using heritability estimates. In most cases, the strain means were continuously distributed; however, strains with deviating high or low intakes or preferences were also observed. The associations among the responses to different minerals were only modest, suggesting distinct genetic controls of sodium, potassium, calcium, and ammonium consumption. These results provide a valuable resource for investigators who wish to identify genes involved in the regulation of mineral consumption and balance.

Bachmanov, Alexander A.; Beauchamp, Gary K.; Tordoff, Michael G.

2007-01-01

257

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

NASA Astrophysics Data System (ADS)

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.

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

1982-05-01

258

Electronic states of AgCl nanocrystals embedded in crystalline KCl studied by 95-GHz optically detected magnetic resonance spectroscopy  

NASA Astrophysics Data System (ADS)

The properties of shallow electron centers (SEC), self-trapped holes (STH), and self-trapped excitons (STE) are investigated in nanocrystals of AgCl embedded in a crystalline KCl matrix. Time-resolved photoluminescence (PL) measurements reveal a behavior different from that in bulk AgCl: an inhomogeneous distribution of the properties of the recombination centers is revealed by the spectral dependence of the decay rates. In time scales from nano- to microseconds, slower rates are systematically observed at the low-energy side of the emission range. In high-frequency (95GHz) optically detected magnetic resonance (ODMR) measurements, the transitions of SEC and STH centers are only observed in the extreme-low energy tail of the PL emission and they exhibit a broad and asymmetric g -value distribution (width ?g?0.07 ), ranging up from the respective bulk g -values. A complex behavior of the ODMR spectrum in the STE region is revealed, showing different spectra at 1.8K and at higher temperature, and, different from the bulk AgCl case, exhibiting a strong dependence upon variation of the detection photon energy. Analysis of the measurements at 4.6K yields a zero field splitting in the STE triplet state in good agreement with the bulk value, while the g -values are slightly increased relative to bulk, which is ascribed to the nanocrystal environment.

Janssen, G.; Bouwen, A.; Goovaerts, E.

2005-01-01

259

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

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

260

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

PubMed Central

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 ?-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.

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

2012-01-01

261

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

SciTech Connect

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

Hingorani-Norenberg, S.L. (Sandia National Labs., Albuquerque, NM (USA)); Razani, A.; Shahinpoor, M. (New Mexico Univ., Albuquerque, NM (USA). Dept. of Mechanical Engineering)

1990-01-01

262

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

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)

Sung Bin Park; Jong Hyeon Lee; Sung Chan Hwang; Young Ho Kang; Joon Bo Shim; Han Soo Lee; Eung Ho Kim; Seong Won Park [Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

2007-07-01

263

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

SciTech Connect

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

Hingorani-Norenberg, S.L.R.

1988-11-01

264

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

Microsoft Academic Search

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

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

1986-01-01

265

Synthesis of rare earth phosphates in molten LiCl–KCl eutectic: Application to preliminary treatment of chlorinated waste streams containing fission products  

Microsoft Academic Search

The precipitation of rare earth phosphates (RE=La, Ce, Pr, Nd, and Lu), from RECl3 was investigated in molten LiCl–KCl eutectic at 500°C in air. Ammonium dihydrogenphosphate (NH4H2PO4) was used as the phosphorus precursor. X-ray diffraction analysis indicated the formation of compounds with monazite (La, Ce, Pr, and Nd) or xenotime (Lu) structures. 31P NMR spectroscopy measurements confirmed that lanthanum formed

Damien Hudry; Isabelle Bardez; Aydar Rakhmatullin; Catherine Bessada; Florence Bart; Stéphane Jobic; Philippe Deniard

2008-01-01

266

Impedance spectroscopy of the Ti(IV)\\/Ti(III) redox couple in the molten LiCl-KCl eutectic melt at 470°C  

Microsoft Academic Search

The electrochemical oxidation of Ti3+ ions in LiCl-KCl eutectic melt at 470°C occurs in two different ways according to the current densities. In our experimental conditions (concentration of Ti3+ ions 0.11 mol kg-1) for potentials lower than -0.48 V (vs chlorine electrode) and current densities lower than 10 mA cm-2 soluble Ti4+ ions are formed, whereas, for higher potentials solid

D. M. Ferry; G. S. Picard

1990-01-01

267

Electrochemical codeposition of Mg-LiGd alloys from LiCl-KCl-MgCl 2Gd 2O 3 melts  

Microsoft Academic Search

Mg-Li-Gd alloys were prepared by electrochemical codeposition from LiCl-KCl-MgCl2-Gd2O3 melts on molybdenum electrode with constant current density at 823 and 973 K. The microstructure of the Mg-Li-Gd alloys was analyzed by X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). The results show that magnesium and gadolinium deposit mainly in the first 30 min, and the alloy obtained

Shu-quan WEI; Mi-lin ZHANG; Wei HAN; Yong-de YAN; Meng ZHANG; Bin ZHANG

2011-01-01

268

The effect of ovariectomy on depressed contractions to phenylephrine and KCl and increased relaxation to acetylcholine in isolated aortic rings of female compared to male rabbits.  

PubMed Central

1. Differences in vascular responses to phenylephrine, acetylcholine (ACh) and potassium chloride (KCl) were studied in rabbit aorta from female and male rabbits, in the absence and presence of an inhibitor of nitric oxide (NO) production, NG-nitro-L-arginine methyl ester (L-NAME, 100 microM). 2. Phenylephrine and KCl-induced contractions, were significantly reduced in amplitude (P < 0.01) in the rings from female rabbits compared to those from male rabbits. 3. ACh-induced relaxation was greater (P < 0.01) in aortic rings from females than from males. 4. Incubation of the rings with L-NAME abolished the phenylephrine-induced contraction differences between rings from male and female rabbits. 5. Ovariectomy eliminated the differences in vascular responses to phenylephrine, KCl and ACh of aortic rings from the female rabbits. 6. Both basal and ACh-stimulated release of nitrites from aortic rings was greater (P < 0.01) in vascular tissue from female than male rabbits. 7. These results indicate that differences in vascular reactivity in aortic rings from male and female rabbits may be associated with a higher release of NO, resulting in an increased vasodilator response in the female rabbits.

Sanchez, A.; Gomez, M. J.; Dorantes, A. L.; Rosales, J. L.; Pastelin, G.; Diaz, V.; Posadas, F.; Escalante, B.

1996-01-01

269

Oriented silver chloride microcrystals and nanocrystals embedded in a crystalline KCl matrix, as studied by means of electron paramagnetic resonance and optically detected magnetic resonance  

NASA Astrophysics Data System (ADS)

Self-trapped holes (STH), self-trapped excitons (STE) and shallow electron centres in small AgCl crystals embedded in a KCl crystalline matrix have been observed by means of optically detected magnetic resonance (ODMR). The existence of the impurity clusters in heavily doped KCl:AgCl single crystals, ranging from single and paired Ag ions to AgCl nanometre- and micrometre-size crystals (nanocrystals and microcrystals) retaining the orientation of the matrix, was confirmed. ODMR spectra were used as a fingerprint of the embedded AgCl microcrystals and a signature of their crystallinity. For AgCl nanocrystals the anisotropy of the g-factor both for isolated STH and for STH forming STE was found to be substantially reduced compared with those of bulk AgCl crystals and AgCl microcrystals embedded in KCl. This implies a considerable suppression of the Jahn-Teller effect in nanoparticles. A rather general mechanism of the suppression of the Jahn-Teller effect in nanocrystals is developed, taking into account the additional deformation field appearing because of the strong vibronic interaction at the interface. It allows evaluation of the critical size of the embedded AgCl nanocrystals, at which the suppression of the Jahn-Teller effect has its onset; the value obtained is ?10 nm, in agreement with experiment.

Baranov, P. G.; Romanov, N. G.; Khramtsov, V. A.; Vikhnin, V. S.

2001-03-01

270

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

SciTech Connect

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

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

1997-07-01

271

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

PubMed

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. PMID:24068817

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

2013-09-25

272

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

SciTech Connect

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.

Yagnik, S.K.

1982-09-01

273

A novel N-terminal isoform of the neuron-specific K-Cl cotransporter KCC2.  

PubMed

The neuronal K-Cl cotransporter KCC2 maintains the low intracellular chloride concentration required for the hyperpolarizing actions of inhibitory neurotransmitters gamma-aminobutyric acid and glycine in the central nervous system. This study shows that the mammalian KCC2 gene (alias Slc12a5) generates two neuron-specific isoforms by using alternative promoters and first exons. The novel KCC2a isoform differs from the only previously known KCC2 isoform (now termed KCC2b) by 40 unique N-terminal amino acid residues, including a putative Ste20-related proline alanine-rich kinase-binding site. Ribonuclease protection and quantitative PCR assays indicated that KCC2a contributes 20-50% of total KCC2 mRNA expression in the neonatal mouse brain stem and spinal cord. In contrast to the marked increase in KCC2b mRNA levels in the cortex during postnatal development, the overall expression of KCC2a remains relatively constant and makes up only 5-10% of total KCC2 mRNA in the mature cortex. A rubidium uptake assay in human embryonic kidney 293 cells showed that the KCC2a isoform mediates furosemide-sensitive ion transport activity comparable with that of KCC2b. Mice that lack both KCC2 isoforms die at birth due to severe motor defects, including disrupted respiratory rhythm, whereas mice with a targeted disruption of the first exon of KCC2b survive for up to 2 weeks but eventually die due to spontaneous seizures. We show that these mice lack KCC2b but retain KCC2a mRNA. Thus, distinct populations of neurons show a differential dependence on the expression of the two isoforms: KCC2a expression in the absence of KCC2b is presumably sufficient to support vital neuronal functions in the brain stem and spinal cord but not in the cortex. PMID:17715129

Uvarov, Pavel; Ludwig, Anastasia; Markkanen, Marika; Pruunsild, Priit; Kaila, Kai; Delpire, Eric; Timmusk, Tônis; Rivera, Claudio; Airaksinen, Matti S

2007-10-19

274

Puerarin facilitates Ca(2+)-induced Ca(2+) release triggered by KCl-depolarization in primary cultured rat hippocampal neurons.  

PubMed

The effects of puerarin on behaviour and brain neuronal activity in animal studies have been described previously. However, molecule mechanisms underlying these effects were poorly understood. Here, we examined the regulation of puerarin on the Ca(2+) signals in primary rat hippocampal neurons using Fura-2 based calcium imaging techniques. Application of puerarin had no effect on the basal intracellular calcium concentration ([Ca(2+)](i)), but potentiated the KCl-evoked [Ca(2+)](i) transient in 87% of recorded neurons. Dantrolene or ruthenium red, the inhibitors of ryanodine receptors, completely blocked this potentiation induced by puerarin. Moreover, in Ca(2+)-free solution, pre-application of puerarin significantly augmented the elevation of [Ca(2+)](i) evoked by caffeine (3 mM), which is a specific agent to activate the ryanodine receptors. In contrast, nifedipine failed to prevent the potentiation induced by puerarin. Similarly, in the experiments of whole-cell patch-clamp recording, puerarin did not show any effect on calcium currents generated by depolarization pulses. These data demonstrated that the potentiation induced by puerarin was attributed to the facilitation of Ca(2+)-induced Ca(2+) release (CICR) via ryanodine receptors, rather than extracellular Ca(2+) influx. Using estrogen receptor antagonist ICI 182780 and tamoxifen, we further demonstrated that the potentiation induced by puerarin was mediated by the estrogen receptor. Furthermore, the membrane-permeant inhibitor of protein kinase A (PKA) H89 completely inhibited this potentiation. However, U-73122, the inhibitor of phospholipase C (PLC) had no effect, indicating that the cyclic AMP/PKA signaling pathway was involved in the activation of CICR by puerarin. PMID:17610871

Lin, Fankai; Xin, Yan; Wang, Jianghua; Ma, Liqun; Liu, Jue; Liu, Chao; Long, Lihong; Wang, Fang; Jin, You; Zhou, Jun; Chen, Jianguo

2007-09-10

275

Stability of CO 2 clathrate hydrate + CO 2 liquid + CO 2 vapour + aqueous KCl-NaCl solutions: Experimental determination and application to salinity estimates of fluid inclusions ?  

NASA Astrophysics Data System (ADS)

The dissociation temperature of CO 2 clathrate hydrate ( Tmcla) in the presence of CO 2 liquid + CO 2 vapour + aqueous KCl-NaCl solutions has been determined by microthermometry of fluid inclusions synthesized in quartz. The reliability of the experimental method as a means to examine clathrate equilibria in this four-phase (Q 2) assemblage has been confirmed by reproducing independent results in the literature on the NaCl-CO 2-H 2O system. Regression fitting of the new experimental measurements and interpolation with published NaCl-CO 2-H 2O data allows the stability of CO 2 clathrate in the Q 2 assemblage of the KCl-NaCl-CO 2-H 2O quaternary system to be described as follows: wt% ( KCl + NaCl) = 15.5296 + 4.2947 XKCL + 0.5061 ( XKCL) 2 -1.0709 TmCLA - 0.4751 TmCLA - 0.048( TmCLA) 2 (1) where wt% (KC1 + NaCl) denotes the total salt concentration in the aqueous liquid (with respect to the salt-H 2O subsystem), TmCLA is in °C, and XKCL denotes the relative weight fraction of salts: wt% KCl/ (wt% KCl + wt% NaCl). This equation is valid over the range 0-19 wt% (KC1 + NaCl), and 0-1 XKCL When coupled with fluid inclusion KCl/NaCl ratios analyzed by methods other than microthermometry, Eqn. (1) yields compositions in terms of individual electrolyte concentrations. In natural fluid inclusions, depending on their bulk compositions and densities, clathrate may dissociate as part of the Q 2 assemblage (for which ThCO2> TmCLA), or in either of two three-phase assemblages (for which ThCO2< TmCLA). The new experimental data on the Q 2 assemblage, and those in the literature, may be applied to natural three-phase assemblages as well. This is enabled by the following functions which relate TmCLA, and ThCO2 measured in the metastable absence of clathrate, to equivalent wt% NaCl in the salt-H 2O subsystem of the aqueous liquid. For inclusions in which CO 2 homogenizes via a bubblepoint transition ( ThCO2< TmCLA): eq. wt% NaCl = 15.6151 - 0.03627 x + 0.00164 x2 - 0.9491 y - 0.00287 xy - 0.02464 y2 - 0.00107 xy2 - 0.00222 y3. (2) For inclusions in which CO 2 homogenizes via a dew-point transition ( ThCO2dew < TmCLA): eq. wt% NaCl = 15.5131 + 0.065705 x - 0.00778 x2 - 1.05135 y + 0.02687 xy - 0.04717 y2 + 0.00138 xy2 - 0.00411 y3 (3) where x denotes ThCO2 between -20 and + 10°C, y denotes TmCLA, and eq. NaCl concentration is between 0 and 21 wt%. Equations (2) and (3) thus permit salinities to be estimated for the large class of natural KCl-NaCl-CO 2-H 2O fluid inclusions in which ThCO2is higher than the clathrate nucleation temperature.

Diamond, Larryn W.

1992-01-01

276

Polishing Methods for KCl.  

National Technical Information Service (NTIS)

Polishing techniques used by AFCRL for polishing alkali halides are described. A brief rationale is given for the techniques and materials required for low damage window polishing. Step-by-step procedures are outlined for use by technician or higher level...

W. S. Ewing

1974-01-01

277

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

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.

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

1986-03-01

278

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

279

Femtosecond fiber laser pulses amplified by a KCl:Tl+ color-center amplifier for continuum generation in the 1.5- mu m region  

NASA Astrophysics Data System (ADS)

A diode-pumped stretched-pulse additive-pulse mode-locked Er-doped fiber laser is used to seed a KCl:Tl+ color-center amplifier crystal. The initial l-nJ chirped pulses are double passed through the amplifier, which is pumped by a 1-kHz Q -switched Nd:YAG laser. The resulting 10- mu J pulses are then chirp compensated to 250-fs duration and are used to generate a spectral continuum. A few high- n2 materials are investigated for continuum generation, and spectral slicing of the continuum is demonstrated.

Lenz, G.; Gellermann, W.; Dougherty, D. J.; Tamura, K.; Ippen, E. P.

1996-01-01

280

Magnetic properties of KClO3-doped Y(1-0.2x)Ba(2- 0.2x)KxCu3Oy, (x = 0-0.40) HTSC  

NASA Astrophysics Data System (ADS)

The influence of KClO3 addition on the magnetic properties and microstructural parameters (grain size, grain boundaries) of high-temperature superconductors (HTSC) with nominal composition Y(1-0.2x)Ba(2- 0.2x)KxCu3Oy (x = 0-0.40) were investigated. The ac complex susceptibility ?ac = ?'-i?'' was recorded as a function of temperature and concentration of KClO3 at various ac magnetic fields up to 2 mT. The data were analysed using the relation h = a(1-Tm/Tc)n, where Tm represents the intergranular peak temperature of the imaginary component ?''. The value of a is found to increase for doped samples, which suggests enhanced flux pinning due to the KClO3 addition. The dc susceptibility as a function of temperature was measured by means of a SQUID magnetometer in field-cooled cooling (FCC) and field-cooled warming (FCW) modes in magnetic fields in the range 10 mT?µ0Ha?7 T on KClO3-doped and pure YBCO samples. The Meissner curves reveal that the samples are single phase in all applied fields, but the low-temperature behaviour of the samples with KClO3 additions is different from that of pure YBCO.

Koblischka-Veneva, A.; Koblischka, M. R.; Ogasawara, K.; Murakami, M.

2000-06-01

281

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

SciTech Connect

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.

Ammon Williams; Supathorn Phongikaroon; Michael Simpson

2013-02-01

282

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

NASA Astrophysics Data System (ADS)

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

Antoci, S.; Mihich, L.

1980-01-01

283

Thermal and x-ray diffraction analyses of reactions of B/CaCrO sub 4 and Ti/KClO sub 4 pyrotechnic blends  

SciTech Connect

Thermal and x-ray diffraction (XRD) analyses have been used in studying reactions of pyrotechnic blends. The reactions were performed in the thermal analysis instrument, and the products were analyzed by XRD. Two pyrotechnic blends -- B/CaCrO{sub 4} and Ti/KClO{sub 4} -- were studied in different reaction environments, including: air, high purity argon, and high vacuum. Thermogravimetric Analysis/Differential Thermal Analysis (TGA/DTA) of a 20/80 wt % B/CaCrO{sub 4} blend in air showed a weight gain (TGA) and an increase in the reaction enthalpy (DTA), compared to reactions in a vacuum or high purity argon. Analyses (TGA/DTA) of a 33/67 wt % Ti/KClO{sub 4} blend in air showed an additional DTA exotherm, following the main reaction peak, accompanied by a small weight gain. Neither was observed in high purity argon or in a vacuum. Reaction products from both blends were determined by XRD. 4 refs., 2 figs., 1 tab.

Whitaker, R.B.; Brown, C.R.; Garrod, M.J.; Sebastian, C.S.; Sullenger, D.B.

1991-01-01

284

Laser initiation of TiH/sub x//KClO/sub 4/ (x = 0. 2, 0. 65, 1. 65). [Argon laser  

SciTech Connect

A laser initiation system for measuring the ignition properties of pyrotechnics and explosives is described. The laser source is a continuous wave (cw) argon laser operating in the visible wavelength region. A shutter-chopper system converts the cw beam to a pulsed beam. The 514.5 nm line with a chopped pulse width of 3 milliseconds was used to ignite the three pyrotechnic compositions TiH/sub x//KClO/sub 4/(x = 0.2, 0.65, 1.65). In an argon atmosphere of 0.79 MPa, the ignition thresholds with a focused Gaussian beam diameter of 66 microns were 554, 866, and 657 microjoules for the three respective compositions. The ignition properties of TiH/sub x//KClO/sub 4/ are found to be strongly dependent on pressure. Rapid changes in the reflectivity of the sample surface also occur within microseconds after application of the laser pulse. 12 refs., 5 figs., 1 tab.

Holy, J.A.

1986-07-01

285

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

SciTech Connect

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

Ulrich, Thomas; Mavrogenes, John (Australian National University)

2008-04-22

286

Measurements of heat capacities at constant volume for aqueous salt solutions (H 2O+NaCl, H 2O+KCl and H 2O+NaOH) near the critical point of pure water  

Microsoft Academic Search

Measurements of isochoric heat capacities CVX for pure water and aqueous salt solutions (H2O+NaCl, H2O+KCl and H2O+NaOH) as a function of temperature along the critical isochores and on the coexistance curves for different concentrations are reported. For binary system H2O+KCl, measurements of CVX along four isochores (333.11, 368.32, 415.97, and 598.09 kg m?3) near the critical point of pure water

I. M. Abdulagatov; V. I. Dvoryanchikov; B. A. Mursalov; A. N. Kamalov

1998-01-01

287

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

USGS Publications Warehouse

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

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

1990-01-01

288

Comparative study of various pretreatment reagents on rice husk and structural changes assessment of the optimized pretreated rice husk.  

PubMed

The performance of alkalis (NaOH and Ca(OH)2) and acids (H2SO4, HCl, H3PO4, CH3COOH, and HNO3) in the pretreatment of rice husk was screened, and a suitable reagent was assessed for subsequent optimization using response surface methodology. From the assessment, HCl that hydrolysed rice husk well was optimized with three parameters (HCl loading, pretreatment duration, and temperature) using Box-Behnken Design. The optimized condition (0.5% (w/v) HCl loading, 125 °C, 1.5 h) is relatively mild, and resulted in ~22.3mg TRS/ml hydrolysate. The reduced model developed has good predictability, where the predicted and experimental results differ by only 2%. The comprehensive structural characterization studies that involved FT-IR, XRD, SEM, and BET surface area determination showed that the pretreated rice husk consisted mainly of cellulose and lignin. Compared to untreated rice husk, pretreated rice husk possessed increased pore size and pore volume, which are expected to be beneficial for fungal growth during fermentation. PMID:23138072

Ang, Teck Nam; Ngoh, Gek Cheng; Chua, Adeline Seak May

2013-05-01

289

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

PubMed

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

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

2014-01-28

290

Preparation and characterization of hydroxyapatite/collagen nanocomposite gel.  

PubMed

The self-organized hydroxyapatite/colagen (HAp/Col) nanocomposite fiber (79.6/20.4 weight ratio) was synthesized by a co-precipitation method using Ca(OH)2, H3PO4, and Col as starting substances. The gelation of the nanocomposite is essential in the application of the scaffold for bone tissue engineering. We successfully prepared HAp/Col nanocomposite gels by a facile novel method using a sodium phosphate buffer at pH 6.8. The water-insoluble nanocomposite was homogeneously dispersed in the buffer to form a viscous mixture, and gels were obtained after incubating of the mixture at 37 degrees C. The mechanical strength of the gels was analyzed against the incubation time. The demineralized gel with EDTA had the typical nanostructure of native type I Col fibers from the results of scanning electron microscopy (SEM) and atomic force microscopy (AFM); the dense network of type I Col nano-fibers below 100 nm in diameter, and the periodic pattern of 68.8+/-4.4 nm (mean +/- SD) along the fibers were observed. The gelation of the HAp/Col nanocomposite in the buffer is attributed to the physical cross-linking through entanglement of the reconstituted Col fibrils. PMID:17450839

Yunoki, Shunji; Ikoma, Toshiyuki; Monkawa, Akira; Ohta, Kazushi; Tanaka, Junzo

2007-03-01

291

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

PubMed

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

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

2005-03-01

292

Nano-hydroxyapatite/poly(L-lactic acid) composite synthesized by a modified in situ precipitation: preparation and properties.  

PubMed

Nano-hydroxyapatite/poly(L-lactic acid) (nano-HA/PLLA) composites with uniform HA distribution and good mechanical performance were fabricated by a modified in situ precipitation method, using Ca(OH)(2) and H(3)PO(4) as precursors for the synthesis of HA phase. This method has solved the aggregation problem of the nano-sized particles in the polymer matrix. The X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy were used to characterize the phase composition, chemical interactions and morphology of the composites, while the mechanical properties were determined by compressive measurements. The results show that the rod-like nano-HA particles synthesized by this method were uniformly distributed in the PLLA matrix. The compressive strength and Young's modulus of the composites were greatly enhanced and reached the values of 155 MPa and 3.6 GPa at 20 wt% HA content, respectively, which are much higher than those of the reference samples fabricated by direct mixing of PLLA with nano-HA particles. This supports the potential of these composites for applications in bone tissue engineering and load bearing bone defects repair. PMID:20890640

Zhang, C Y; Lu, H; Zhuang, Z; Wang, X P; Fang, Q F

2010-12-01

293

Consequence of condensed-phase formation in transient burning of TiH/sub x//KClO/sub 4/ in a closed system  

SciTech Connect

Transient burning of TiH/sub X//KClO/sub 4/ in a closed system is formulated including the effect of condensed species. Thermodynamic properties are evaluated using both BLAKE and TIGER computer codes. Three different equations of state for gaseous species are used and their effect on the burning rate is evaluated. For more accurate transient burning analysis, a pressure dependent covolume for gaseous species is generated. The effect of pressure dependent covolume as well as the condensed species on transient burning is evaluated. Both parameters are found to be important when the burning rate at high loading densities in a closed system is considered. At high loading densities, condensed species become important not only because of the their effect on thermodynamic properties but also due to the volume occupied by these species. 11 refs., 2 figs., 2 tabs.

Razani, A.; Shahinpoor, M.; Hingorani-Norenberg, S.L.

1989-01-01

294

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

SciTech Connect

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

Xu Lianqiang, E-mail: xuwenqiang998@126.com [Department of Physics and Information Technology, Ningxia Teachers University, Guyuan Ningxia, 756000 (China); Cheng Li [Department of Physics and Information Technology, Ningxia Teachers University, Guyuan Ningxia, 756000 (China)

2010-02-15

295

Metals in IRC+10216 - Detection of NaCl, AlCl, and KCl, and tentative detection of AlF  

NASA Astrophysics Data System (ADS)

The authors report the first detection of metal halides in IRC +10216. The millimetre-wave line profiles suggest that these species are concentrated in the inner circumstellar envelope. The abundances derived for NaCl, AlCl, KCl, and tentatively for AlF, are in the range 1012 - 1014cm-2 and are 106 - 108times lower than the abundance of H2. They agree with the chemical equilibrium abundances calculated by Tsuji (1973) for a carbon-rich stellar atmosphere with a temperature 1200 - 1500K. The lines of NaCl and AlCl, observed with the IRAM 30m telescope, are strong enough to allow the detection of these species' rare 37Cl isotopes. The derived 35Cl/37Cl isotopic ratio (2.3±0.5) is consistent with the terrestrial elemental isotopic ratio.

Cernicharo, J.; Guelin, M.

1987-09-01

296

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

297

Growth of textured films of Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+//sub x/ from KCl solution  

SciTech Connect

Films of Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+//sub x/ have been grown from KCl solution. Gadolinium gallium garnet substrates (1 1 1) oriented have been used. The films resulted highly textured with the c axis perpendicular to the substrate surface. The onset of the resistive transition was 85 K, while zero resistance was obtained at 50 K. This technique is particularly promising in view of the possibility to grow large epitaxial films of both the Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+//sub x/ and the Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10+//sub x/ phases.

Balestrino, G.; Paoletti, A.; Paroli, P.; Romano, P.

1989-05-15

298

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

PubMed

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

Gimeno, O; Astiasarán, I; Bello, J

1999-03-01

299

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

SciTech Connect

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.

Lantelme, F.; Berghoute, Y.

1999-11-01

300

Electrochemical Codeposition of Al-Li-Mg Alloys at Solid Aluminum Electrode from LiCl-KCl-MgCl2 Molten Salt System  

NASA Astrophysics Data System (ADS)

The electrochemical codeposition of Mg and Li at an aluminium electrode in LiCl-KCl (50:50 wt pct) melts containing different concentrations of MgCl2 at 893 K (620 °C) to form Al-Li-Mg alloys was investigated. Cyclic voltammograms showed that the potential of Li metal deposition at an Al electrode, before the addition of MgCl2, is more positive than that of Li metal deposition at an Mo electrode, which indicated the formation of an Al-Li alloy. The underpotential deposition of magnesium at an aluminium electrode leads to the formation of Al-Mg alloys, and the succeeding underpotential deposition of lithium on predeposited Al-Mg alloys leads to the formation of Al-Li-Mg alloys. Chronopotentiometric measurements indicated that the codeposition of Mg and Li occurs at current densities lower than -0.668 A cm-2 in LiCl-KCl-MgCl2 (8 wt pct) melts at an aluminium electrode. The chronoamperometric studies indicated that the onset potential for the codeposition of Mg and Li is -2.000 V, and the codeposition of Mg and Li at an aluminium electrode is formed into Al-Li-Mg alloys when the applied potentials are more negative than -2.000 V. X-ray diffraction and inductively coupled plasma analysis indicated that Al-Li-Mg alloys with different lithium and magnesium contents were prepared via potentiostatic and galvanostatic electrolysis. The microstructure of typical dual phases of the Al-Li-Mg alloy was characterized by an optical microscope and by scanning electron microscopy. The analysis of energy dispersive spectrometry showed that the elements of Al and Mg distribute homogeneously in the Al-Li-Mg alloy. The lithium and magnesium contents of Al-Li-Mg alloys can be controlled by MgCl2 concentrations and by electrolytic parameters.

Ye, Ke; Zhang, Mi Lin; Chen, Ye; Han, Wei; de Yan, Yong; Cao, Peng

2010-06-01

301

Seizure Sensitivity Is Ameliorated by Targeted Expression of K+-Cl? Cotransporter Function in the Mushroom Body of the Drosophila Brain  

PubMed Central

The kccDHS1 allele of kazachoc (kcc) was identified as a seizure-enhancer mutation exacerbating the bang-sensitive (BS) paralytic behavioral phenotypes of several seizure-sensitive Drosophila mutants. On their own, young kccDHS1 flies also display seizure-like behavior and demonstrate a reduced threshold for seizures induced by electroconvulsive shock. The product of kcc shows substantial homology to KCC2, the mammalian neuronal K+–Cl? cotransporter. The kccDHS1 allele is a hypomorph, and its seizure-like phenotype reflects reduced expression of the kcc gene. We report here that kcc functions as a K+–Cl? cotransporter when expressed heterologously in Xenopus laevis oocytes: under hypotonic conditions that induce oocyte swelling, oocytes that express Drosophila kcc display robust ion transport activity observed as a Cl?-dependent uptake of the K+ congener 86Rb+. Ectopic, spatially restricted expression of a UAS-kcc+ transgene was used to determine where cotransporter function is required in order to rescue the kccDHS1 BS paralytic phenotype. Interestingly, phenotypic rescue is largely accounted for by targeted, circumscribed expression in the mushroom bodies (MBs) and the ellipsoid body (EB) of the central complex. Intriguingly, we observed that MB induction of kcc+ functioned as a general seizure suppressor in Drosophila. Drosophila MBs have generated considerable interest especially for their role as the neural substrate for olfactory learning and memory; they have not been previously implicated in seizure susceptibility. We show that kccDHS1 seizure sensitivity in MB neurons acts via a weakening of chemical synaptic inhibition by GABAergic transmission and suggest that this is due to disruption of intracellular Cl? gradients in MB neurons.

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

2010-01-01

302

Dietary NaCl-restriction prevents the calciuria of KCl-deprivation and blunts the calciuria of KHCO3-deprivation in healthy adults.  

PubMed

Previous studies have demonstrated that dietary potassium deprivation in healthy human subjects eating diets otherwise containing normal quantities of NaCl is accompanied by an increase in urinary calcium excretion. This increase in urinary Ca excretion occurs in association with reductions in urinary Na and Cl excretion together with trends for weight gain and is delayed for several days after the initiation of K-deprivation, suggesting that it is mediated by NaCl retention and expansion of the extra-cellular volume. The present studies were thus undertaken to determine whether dietary NaCl restriction prevents the calciuric effect of subsequent K-deprivation. When dietary NaCl intake was limited to 5 +/- 3 mmol/day among 10 healthy adults, subsequent deprivation of KCl (-67 mmol/day) in 5 subjects of deprivation of KHCO3 (-64 mmol/day) in 5 subjects prevented any significant increase in daily urinary Ca excretion during five days of K-deprivation. There was, however, a small but significant cumulative increase above control in urinary Ca excretion at the end of KHCO3-deprivation, averaging + 1.9 +/- 0.6 mmol; P < 0.05. When KCl was restored to the diets urinary Ca excretion increased while restoration of KHCO3 to the diets caused urinary Ca to fall to rates below control. We conclude that the calciuria of K-deprivation when NaCl is present in the diet is largely dependent upon NaCl retention by the kidneys and subsequent ECF-volume expansion. In addition, HCO3 is anti-calciuric. PMID:7752590

Lemann, J; Pleuss, J A; Hornick, L; Hoffman, R G

1995-03-01

303

A Very Precise Canonical Ensemble Monte Carlo Determination of Thermodynamic Properties and of Radial Distribution Functions and Electric Potentials Around Ions in a Primitive Model of 2M Mixtures of KCl and KF at 25°C  

Microsoft Academic Search

Long-run Canonical Ensemble Monte Carlo Simulations (up to 30 million configurations) of a primitive model KCl-KF electrolyte mixture at a total concentration 2 M and at 25°C have been performed for a wide range of the number of ions (N) in the simulation cell (from N = 16 up to N = 1728) and for a number of ratios between

Torben Smith Sørensen

1995-01-01

304

Evidence for the involvement of K+ channels and K(+)-Cl- cotransport in the regulatory volume decrease of newborn rat cardiomyocytes.  

PubMed

In order to delineate ion transport mechanisms involved in volume homeostasis of freshly isolated newborn rat ventricular myocytes, we investigated the effects of ion substitutions and pharmacological maneuvers upon (1) isotonic volume, (2) hypotonically induced initial swelling, and (3) the subsequent regulatory volume decrease (RVD), as determined by electronic cell sizing. Cardiomyocytes exposed to hypotonic medium (176 mosmol/l) swelled by 51+/-1% of isotonic volume, and they underwent a partial regulatory volume decrease (RVD), reaching a maximum regulation after 30 min (51+/-1% of initial swelling), with a half-time (t1/2) of 6+/-1 min (n=60). RVD was associated with significant cardiomyocyte K+ loss (12+/-4% at 5 min and 15+/-2% of isotonic control after 30 min: n=6, P<0.001), 71% of which was Cl- dependent (P<0.05). Within the 30-min experimental time frame, ouabain, a Na+/K+ pump inhibitor, had no significant effect on RVD (despite an inhibitory trend), cell swelling or on isotonic volume (n=6). Bumetanide (50 microM), a Na+-K+-Cl- co-transport blocker, induced a significant reduction of isotonic cell volume (3+/-2%, n=6. P<0.05), potentiated initial swelling by 16+/-1% (n=8, P<0.02), and it partially inhibited RVD (24+/-11% at 30 min, n=6), whereas Na+ omission had no significant effect on isotonic cell volume, cell swelling or RVD. The effects of bumetanide on initial swelling and RVD were prevented by gadolinium ion (10 microM), a stretch-activated cation channel blocker (n=5). Quinidine (500 microM), a non-selective Ca(2+)-activated potassium channel blocker with no side-effects on K(+)-Cl(-) cotransport, did not modify initial cell swelling, but inhibited RVD (50+/-3% at 5 min, n=9, P<0.01; 22+/-3% at 30 min), an effect which was cancelled by external Ca2+ chelation with EGTA (n=5), and reproduced by tetraethylammonium (TEA, 20 mM), another K+ channel blocker. 4,4'-Diisothiocyanatostilbene 2,2'-disulfonic acid (DIDS, 100 microM), a non-selective swelling-activated Cl- channel blocker with marginal side-effects on K(+)-Cl(-)cotransport, did not modify initial swelling, but inhibited RVD to the same extent as quinidine (42+/-3% at 5 min, and 23+/-3% at 30 min, n=15, P<0.05), whereas hypotonic Cl(-)-free solution had no effect on isotonic volume, but potentiated initial swelling by 16+/-2% (P<0.05) and fully inhibited RVD (n=5, P<0.001). R(+)-[(2-n-Butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inde n-5yl)-oxy] acetic acid) (DIOA, 80 microM), a K(+)-Cl- cotransport blocker (with inhibitory potency toward Ca(2+)-activated K+ channels), inhibited 87+/-5% of the RVD process at 5 min (P<0.001) and 56+/-16% at 30 min (P<0.001), whereas it had a small effect on isotonic volume (+4%, P<0.01) and initial cell swelling (+2%, N.S.; n=9). In contrast to quinidine, DIOA was able to inhibit Ca(2+)-omission-resistant RVD (full inhibition at 5 min, and 56+/-9% at 30 min; P<0.01, n=5). In conclusion, our results suggest that at least three distinct ion transport mechanisms are involved in the RVD in newborn rat cardiomyocytes: (1) K+ and Cl-channels, (2) K(+)-Cl- cotransport, and (3) Na(+)-K(+)-Cl- co-transport. PMID:10651001

Taouil, K; Hannaert, P

1999-12-01

305

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

SciTech Connect

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.

Nekahi, Atiye [Mining and Metallurgical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of)] [Mining and Metallurgical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of); Firoozi, Sadegh, E-mail: s.firoozi@aut.ac.ir [Mining and Metallurgical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of)] [Mining and Metallurgical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of)

2011-09-15

306

Features of distinct contractions induced with a high and a low concentration of KCl, noradrenaline, and histamine in swine lingual artery.  

PubMed

We investigated the features of swine lingual artery contraction induced with different strengths of stimulation. Endothelium-denuded artery rings were contracted with two concentrations of KCl, noradrenaline, and histamine with or without Y-27632, sodium nitroprusside (SNP), 2,2-diphenyl-1,3,2-oxaza-borolidine internal salt (2- APB), and extracellular Ca2+. While stored at 5 degrees C up to 3 days, artery rings remained active to strong stimulation but became inactive to weak stimulation if prior warming was lacking. Artery rings contracted slowly and progressively to weak stimulation but rapidly to strong stimulation and then kept a plateau or slightly relaxed. Y-27632, SNP, and 2-APB, irrespective of extracellular Ca2+, attenuated weak-stimulation-induced contractions to much greater extents except that 2-APB similarly diminished contractions to both noradrenaline concentrations. Without extracellular Ca2+, transitory contractions occurred with one peak to strong stimulation and two small peaks to weak stimulation, though one full peak to both noradrenaline concentrations. Artery rings lost stimulant responsiveness when extracellular Ca2+ was absent, but subsequent Ca2+ reintroduction without coexisting stimulant triggered transient contractions, which were as large as contractions to weak stimulation with extracellular Ca2+ and ceased with Y-27632, SNP, and 2-APB. These results collectively suggest that, in the lingual artery, its contraction properties shift coupling with strengths of both receptor- and voltage-mediated stimulation, with the tonic-like component being dominant in weak-stimulation-induced contraction. PMID:20054523

Kawaguchi, Takaki; Satoh, Ken-ichi; Kuji, Akiyoshi; Joh, Shigeharu

2010-02-01

307

Reactions of formation and stability of iron (II) and (III) oxides in LiCl-KCl eutectic melt at 470/degree/c  

SciTech Connect

The study of the different oxides of iron (II) and iron (III) was carried out potentiometrically in LiCl-KCl eutectic at 470/sup 0/C by means of an yttria-stabilized zirconia electrode indicator of the oxide ion activity and an iron electrode indicator of the ferrous ion activity. These measurements were complemented by the determination of cyclic voltammograms and by x-ray diffraction and infrared spectrophotometrY analysis of certain compounds formed. The main results obtained are the following: strong oxidizing power (oxidation of Cl-/sup 1/ ions into Cl/sub 2/) and high oxoacidity (great stability of ferric oxide) of Fe/sup 3/ ions; possible redissolution of Fe/sub 2/O/sup 3/ in the oxide ion rich media by the formation of ferrate (III) ion; FeO/sub 2/-*Fe/sup 2 +/ ions react with O/sup 2/- ions to to form ferrous oxide, which is probably stabilized in the form of a solid solution FeO-LiFeO/sub 2/ of composition Fe/sub 1-y/Li/sub y/O. Magnetic oxide, Fe/sub 3/O/sub 4/, is stable and can be obtained by the action of oxide ions on a mixture of iron (II) and iron (III). This work is pertinent to the construction of rechargeable and high performance batteries. 34 refs.

Picard, G.; Seon, F.; Tremillon, B.

1982-07-01

308

The Electrochemical Formation of Ni-Tb Intermetallic Compounds on a Nickel Electrode in the LiCl-KCl Eutectic Melts  

NASA Astrophysics Data System (ADS)

The work presents an electrochemical study on the formation of Ni-Tb intermetallic compounds in the LiCl-KCl-TbCl3 melts on tungsten and nickel electrodes at 773 K (500 °C) by electrochemical techniques. For a tungsten electrode, cyclic voltammetry and square-wave voltammetry showed that the electrochemical reduction of Tb(III) proceeded in a one-step process involving three electrons at -2.06 V ( vs Ag/AgCl). For a nickel electrode, the reduction potential of Tb(III)/Tb was observed at more positive values than those on W electrode by cyclic voltammetry, due to the formation of Ni-Tb intermetallic compounds. Square-wave voltammetry and open-circuit chronopotentiometry put into evidence the formation of intermetallic compounds at around -1.27, -1.63, and -1.88 V, respectively. Three alloy samples were obtained by potentiostatic electrolysis on a Ni electrode at various potentials and analyzed by X-ray diffraction, scanning electron micrograph, and energy-dispersive spectrometry. The analysis results confirmed the formation of Ni17Tb2, Ni5Tb, and Ni2Tb alloy compounds.

Han, Wei; Sheng, Qingnan; Zhang, Milin; Li, Mei; Sun, Tingting; Liu, Yaochen; Ye, Ke; Yan, Yongde; Wang, Yingcai

2014-06-01

309

Synchronously pumped mode locked 1.73-2.10-micron tunable laser operation of (F2(+)) sub AH centers in KCl:Na(+):O2 crystals  

NASA Astrophysics Data System (ADS)

Using synchronous pumping with about 100-psec-wide 1.32 micron Nd(3+):YAG laser pulses, mode-locked KCl:Na(+):O2(-) (F2(+)) sub AH color center laser operation with nearly-transform-limited about 5-10 psec-wide pulses throughout a 1.73-2.10-micron tuning range are realized. Pulses shorten continuously with increasing pump power levels. At maximum available pump power (about 2.3 W), average output power up to about 380 mW is obtained in the peak of the tuning curve at 1.83 micron. Pulse shape and width measurements show that stable-mode-locked operation is relatively insensitive toward cavity-length detuning. All observed mode-locking characteristics are in good qualitative agreement with theoretical predictions for a synchronously pumped material in which the fluorescence-decay-time is large compared with the cavity round trip time. The new laser provides a high average-power picosecond light source in a wavelength range where only few competing laser systems exist.

Moellmann, K.; Mitschke, F.; Welling, H.; Gellermann, W.

310

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

PubMed

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

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

2006-01-01

311

WNK Protein Kinases Modulate Cellular ClÃÂ Flux by Altering the Phosphorylation State of the Na-K-Cl and K-Cl Cotransporters  

NSDL National Science Digital Library

Precise control of cellular ClÃÂ transport is necessary for many fundamental physiological processes. For example, the intracellular concentration of ClÃÂ, fine-tuned through the coordinated action of cellular ClÃÂ influx and efflux mechanisms, determines whether a neuronÃÂs response to GABA is excitatory or inhibitory. In epithelia, synchrony between apical and basolateral ClÃÂ flux, and transcellular and paracellular ClÃÂ transport, is necessary for efficient transepithelial ClÃÂ reabsorption or secretion. In cells throughout the body, coordination of ClÃÂ 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 ClÃÂ 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 ClÃÂ influx and efflux through SLC12 cotransporters to dynamically regulate intracellular ClÃÂ activity.

Dr. Gerardo Gamba (Universidad Nacional Autónoma de México Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán)

2006-10-01

312

Solubilization of rare earth oxides in the eutectic LiCl–KCl mixture at 450 °C and in the equimolar CaCl 2–NaCl melt at 550 °C  

Microsoft Academic Search

Solubilization studies of rare earth oxides and oxohalides have been carried out in the eutectic LiCl–KCl melt at 450°C and the equimolar CaCl2–NaCl mixture at 550°C. First, chlorinating conditions were predicted by comparing the E–pO2? diagram of the different rare earth-O compounds to that of several chlorinating gaseous mixtures. Then, experimental solubilization tests were performed by using pure HCl and

Y. Castrillejo; M. R. Bermejo; E. Barrado; A. M. Mart??nez; P. D??az Arocas

2003-01-01

313

Enhancement by veratridine and 60 mM KCl of vasopressin-induced 3',5'-cyclic adenosine monophosphate production and cellular free calcium concentration in rat renal papillary collecting tubule cells in culture.  

PubMed

The effect of extracellular calcium (Ca2+) on the cellular action of arginine vasopressin (AVP) was examined using depolarizing agents in rat renal papillary collecting tubule cells in culture. One-hour exposure of cells to veratridine enhanced AVP-induced cAMP production in a dose-dependent manner. This enhancement by veratridine of cellular cAMP production in response to AVP was totally blunted by cotreatment with 5 X 10(-4) M verapamil, 3 X 10(-3) M cobalt, or Ca2+-free medium containing 1 X 10(-3) M EGTA. These agents block cellular Ca2+ uptake by different mechanisms. Similarly, 60 mM KCl enhanced AVP-induced cAMP production, and this effect was blocked by pretreatment with verapamil, cobalt or Ca2+-free medium containing 1 X 10(-3) M EGTA. When cellular free Ca2+ concentrations [Ca2+]i were measured by the fluorescence dye fura-2, both 1 X 10(-4) M veratridine and 60 mM KCl significantly increased [Ca2+]i from 67.6 to 141.8 nM and from 74.6 to 166.2 nM, respectively. Such rises in [Ca2+]i depended on extracellular Ca2+ since the increase in [Ca2+]i was completely blocked in Ca2+-free medium or in the presence of 3 X 10(-3) M cobalt. In addition, veratridine and 60 mM KCl significantly augmented the AVP-induced increase in [Ca2+]i. The possible mechanisms by which depolarizing agents induce cellular Ca2+ mobilization include the opening of voltage-sensitive Ca2+ channels in the plasma membrane. The present results indicate that veratridine and 60 mM KCl enhance AVP-induced cAMP production and cellular free Ca2+ concentration through cellular Ca2+ uptake in renal papillary collecting tubule. PMID:2535807

Ishikawa, S; Saito, T

1989-01-01

314

The relationship of KCl- and prostaglandin F2 alpha-mediated increases in tension of the porcine coronary artery with changes in intracellular Ca2+ measured with fura-2.  

PubMed Central

1. Changes in intracellular free Ca2+ concentration ([Ca2+]i) were measured simultaneously with changes in muscle tension by use of the fluorescent Ca2+ indicator, fura-2, in coronary arterial rings of the pig. 2. Changes in [Ca2+]i were measured by monitoring the ratio of fluorescence due to excitation at 340 nm (F340) to that at 380 nm (F380). 3. Increases in tension of the porcine coronary artery induced by prostaglandin F2 alpha (PGF2 alpha) (2-30 microM) and KCl (25-70 mM) were accompanied by increases in the F340/F380 fluorescence ratio of fura-2. 4. KCl-induced increases in muscle tension, equivalent to those produced by PGF2 alpha, were observed to occur in the presence of a higher [Ca2+]i. 5. Nearly complete relaxation of KCl-induced contractions by sodium nitroprusside (SNP) was accompanied by only a partial reversal of the increase in [Ca2+]i that occurred during contraction. 6. Complete relaxation of the PGF2 alpha-contracted coronary artery by cromakalim (BRL 34915) was accompanied by a nearly complete reversal of the increase in [Ca2+]i caused by the contractile agent. 7. The contractile state of smooth muscle is not an indicator of [Ca2+]i. The [Ca2+]i-tension relationship is dependent upon the type of pharmacological agent that is used to change muscle tension.

Balwierczak, J. L.

1991-01-01

315

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

PubMed Central

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

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

2011-01-01

316

Attenuated responses to endothelin-1, KCl and CaCl2, but not noradrenaline, of aortae from rats with streptozotocin-induced diabetes mellitus.  

PubMed Central

1. This study investigated the responsiveness to vasoconstrictor agents (including endothelin-1, ET-1) of aortic rings from rats with two-week streptozotocin (STZ, 60 mg kg-1, i.v.)-induced diabetes and vehicle-treated control rats. The basal tension was 10 g, which was estimated to be more physiological than the tension of 1-2 g that has been previously used for most studies of aortic rings from diabetic rats. 2. Maximum responses to ET-1 (0.13-18 nM), KCl (2-20 mM) or CaCl2 (10 microM-10 mM) were reduced in aortae from STZ-treated rats compared to those from control rats. Such reductions were still evident after removal of the endothelium. 3. Responses to noradrenaline (NA, 0.1 nM-26 microM) of aortae from STZ-treated rats were not significantly different from responses of aortae of control rats. 4. Removal of endothelium resulted in a significant reduction in the EC50 values for NA of rings from both STZ-treated rats (6.90 +/- 0.13 and 8.17 +/- 0.35 (-log M) with and without endothelium, respectively, n = 5) and control rats (6.90 +/- 0.15 and 8.37 +/- 0.44 (-log M) with and without endothelium, respectively, n = 5). 5. In calcium-free medium (with 1 mM EGTA), responses to NA and ET-1 were reduced compared with those in normal Krebs solution and maximum responses were less in rings from STZ-treated compared with control rats. 6. Indomethacin (5 microM) did not prevent the reduced maximum responsiveness to ET-1 in rings from STZ-treated rats compared with those from controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Fulton, D. J.; Hodgson, W. C.; Sikorski, B. W.; King, R. G.

1991-01-01

317

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

PubMed

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

Grasa, Laura; Ansón-Casaos, Alejandro; Martínez, María Teresa; Albendea, Raquel; De Martino, Alba; Gonzalo, Sergio; Murillo, María Divina

2014-03-01

318

BDNF regulates spontaneous correlated activity at early developmental stages by increasing synaptogenesis and expression of the K+/Cl- co-transporter KCC2.  

PubMed

Spontaneous neural activity is a basic property of the developing brain, which regulates key developmental processes, including migration, neural differentiation and formation and refinement of connections. The mechanisms regulating spontaneous activity are not known. By using transgenic embryos that overexpress BDNF under the control of the nestin promoter, we show here that BDNF controls the emergence and robustness of spontaneous activity in embryonic hippocampal slices. Further, BDNF dramatically increases spontaneous co-active network activity, which is believed to synchronize gene expression and synaptogenesis in vast numbers of neurons. In fact, BDNF raises the spontaneous activity of E18 hippocampal neurons to levels that are typical of postnatal slices. We also show that BDNF overexpression increases the number of synapses at much earlier stages (E18) than those reported previously. Most of these synapses were GABAergic, and GABAergic interneurons showed hypertrophy and a 3-fold increase in GAD expression. Interestingly, whereas BDNF does not alter the expression of GABA and glutamate ionotropic receptors, it does raise the expression of the recently cloned K(+)/Cl(-) KCC2 co-transporter, which is responsible for the conversion of GABA responses from depolarizing to inhibitory, through the control of the Cl(-) potential. Together, results indicate that both the presynaptic and postsynaptic machineries of GABAergic circuits may be essential targets of BDNF actions to control spontaneous activity. The data indicate that BDNF is a potent regulator of spontaneous activity and co-active networks, which is a new level of regulation of neurotrophins. Given that BDNF itself is regulated by neuronal activity, we suggest that BDNF acts as a homeostatic factor controlling the emergence, complexity and networking properties of spontaneous networks. PMID:12588844

Aguado, Fernando; Carmona, Maria A; Pozas, Esther; Aguiló, Agustín; Martínez-Guijarro, Francisco J; Alcantara, Soledad; Borrell, Victor; Yuste, Rafael; Ibañez, Carlos F; Soriano, Eduardo

2003-04-01

319

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

PubMed

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

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

2012-06-01

320

Proton conductive inorganic–organic hybrid membranes prepared from 3-aminopropyltriethoxysilane and phosphoric acid by the sol–gel method  

Microsoft Academic Search

Proton conductive inorganic–organic hybrid membranes with acid–base pairs have been prepared from 3-aminopropyltriethoxysilane and phosphoric acid by the sol–gel method. The self-standing membranes obtained are represented as poly(3-aminopropylsilsesquioxane)-H3PO4 (PAPS–H3PO4) membranes. Infrared absorption spectra of the PAPS–H3PO4 films showed that amino groups of PAPS were protonated by phosphoric acid, indicating the formation of acid–base pairs. X-ray diffraction patterns of the PAPS–H3PO4

Teruaki Tezuka; Kiyoharu Tadanaga; Akitoshi Hayashi; Masahiro Tatsumisago

2008-01-01

321

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

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

S. Frank

2009-09-01

322

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

NASA Technical Reports Server (NTRS)

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.

Holy, John A.

1993-01-01

323

Thermal conductivity under pressure and through phase transitions in solid alkali halides. I. Experimental results for KCl, KBr, KI, RbCl, RbBr and RbI  

Microsoft Academic Search

The thermal conductivity, lambda , of polycrystalline KCl, KBr, KI, RbCl, RbBr and RbI has been measured at temperatures (T) from 100-400K at pressures (P) up to about 2.6 GPa, using the transient hot-wire method. Extensive results were obtained for lambda (T,P) of both the low-pressure (NaCl-type) and high-pressure (CsCl-type) phases. There was generally good agreement with previous results for

P. Andersson

1985-01-01

324

Optical properties and synchronously pumped mode-locked 1.73-2.10 ?m tunable laser operation of (F +2) AH centers in KCl:Na +:O -2 crystals  

NASA Astrophysics Data System (ADS)

Using synchronous pumping with ?100 ps wide 1.32 ?m Nd 3+:YAG laser pulses, we realize mode-locked KCl:Na +:O -2 (F +2) AH color center laser operation with nearly transform limited ?5-10 ps wide pulses throughout a 1.73-2.10 ?m tuning range. Pulses shorten continuously with increasing pump power levels. At maximum available pump power (?2.3 W), average output power up to ?380 mW is obtained in the peak of the tuning curve at 1.83 ?m. Pulse shape and width measurements show that stable mode-locked operation is relatively insensitive towards cavity length detuning.

Möllmann, K.; Mitschke, F.; Gellermann, W.

1991-05-01

325

Growth of epitaxial films of Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8+ sub x onto SrTiO sub 3 substrates from liquid KCl solution  

SciTech Connect

Epitaxial films of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{ital x}} have been grown from liquid KCl solution, onto (100)-oriented SrTiO{sub 3} substrates. The films show a resistance versus temperature behavior of metallic'' character down to the transition temperature. The residual resistance extrapolated at 0 K is 1/10 of resistance at room temperature. The onset of the superconducting transition is at 81 K, and zero resistance is obtained at 78 K.

Balestrino, G. (Dipartimento di Fisica, Universita di Salerno, I-84100 Salerno, (Italy)); Marinelli, M. (Istituto di Elettronica dello Stato Solido del C.N.R., Via Cineto Romano 42, I-00156 Roma, (Italy)); Milani, E.; Paoletti, A.; Paroli, P. (Dipartimento di Ingegneria Meccanica, II Universita di Roma, Via O. Raimondo, I-00173 Roma, (Italy))

1990-07-01

326

Mass Transport and Physical Properties of Large Crystals of Calcium Apatites: Studies of Ca(OH)2 Crystals for Use in Electrolytic Conversion of Calcium Fluorapatite Crystals to Calcium Hydroxyapatite.  

National Technical Information Service (NTIS)

In order to convert single crystals of calcium fluorapatite to calcium hydroxyapatite, an electrolytic cell technique will be explored. To use such a technique, the cathode compartment must consist of a source of hydroxyl ions and a barrier to the flow of...

A. D. Franklin K. F. Young

1973-01-01

327

Mass Transport and Physical Properties of Large Crystals of Calcium Apatites: Studies of Ca(OH)2 Crystals for Use in Electrolytic Conversion of Calcium Fluorapatite Crystals to Calcium Hydroxyapatite.  

National Technical Information Service (NTIS)

In order to convert single crystals of calcium fluorapatite to calcium hydroxyapatite, an electrolytic cell technique will be explored. To utilize such a technique, the cathode compartment must consist of a source of hydroxyl ions and a barrier to the flo...

A. D. Franklin K. F. Young

1975-01-01

328

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

PubMed

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

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

2010-11-01

329

Enhanced bioactivity and osteoconductivity of hydroxyapatite through chloride substitution.  

PubMed

The effect of chloride-substitution on bioactivity and osteoconductivity of hydroxyapatite (OHAp) was newly investigated. Chloride-substituted hydroxyapatites (ClAp) with low and high chloride concentrations were synthesized by reacting Ca(OH)2 and H3 PO4 with NH4 Cl of low and high concentrations, with subsequent sintering. As a control, pure OHAp was prepared under the same conditions but without addition of NH4 Cl. The ClAp showed markedly enhanced bioactivity in simulated body fluid (SBF) as the chloride substitution was increased. In contrast, OHAp did not show any bioactivity at all within the testing period. The solubility tests in deionized water also showed that the higher the chloride-substituting amount, the higher the dissolution amounts of the constituent elements of apatite, which directly affect bioactivity by increasing the degree of supersaturation of apatite in SBF. In addition, ClAp also showed noticeably higher osteoconductivity within the 4 weeks of implantation in calvarial defects of New Zealand white rabbits, compared with that of OHAp. The total system energy of the apatite calculated by the ab initio method showed that the higher the chloride-substituting amount, the higher the total system energy, which suggests that the ClAp was energetically less stable compared with OHAp. This result demonstrates the higher solubility of ClAp over that of OHAp in SBF and deionized water. The improved solubility of the OHAp enhances its bioactivity and consequent osteoconductivity. Taken together, it can be concluded that ClAp has encouraging potential for use as a bone grafting material due to its highly enhanced bioactivity and osteoconductivity compared with pure OHAp. PMID:23533198

Cho, Jung Sang; Yoo, Dong Su; Chung, Yong-Chae; Rhee, Sang-Hoon

2014-02-01

330

Viscosities of l-Histidine/ l-Glutamic Acid/ l-Tryptophan/Glycylglycine + 2 M Aqueous KCl/KNO3 Solutions at T = (298.15 to 323.15) K  

NASA Astrophysics Data System (ADS)

Viscosity values of l-histidine/ l-glutamic acid/ l-tryptophan/glycylglycine + 2 M aqueous KCl/KNO3 solutions have been determined experimentally as a function of molal concentration of amino acid/peptide at different temperatures: (298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K. Using the viscosity values of the solvent and solution, the relative viscosity, specific viscosity, and viscosity B-coefficient values have been computed. The trends of the variation of experimental and computed parameters with the solute concentration and temperature have been interpreted in terms of zwitterions-ions, zwitterions-water dipoles, ions-water dipoles, and ions-ions interactions operative in the systems.

Riyazuddeen; Altamash, Tausif

2011-06-01

331

Effects of minerals on sporulation and heat resistance of Clostridium sporogenes  

Microsoft Academic Search

In this study, various mineral supplements, such as chloride salts (CaCl2, MgCl2, MnCl2, FeCl2 and KCl) supplying cations and calcium salts (CaCl2, CaCO3, CaSO4, Ca(OH)2 and CaHPO4) supplying anions, were tested if they could stimulate the sporulation of Clostridium sporogenes, a surrogate microorganism for C. botulinum. Of the cations tested, the addition of CaCl2 showed a slightly, but not significantly,

Jae-Hyung Mah; Dong-Hyun Kang; Juming Tang

2008-01-01

332

Influence of KClO{sub 3} addition on the magnetic properties and microstructural morphology of Y{sub 1{minus}0.2x}Ba{sub 2{minus}0.2x}K{sub x}Cu{sub 3}O{sub y} (x = 0{divided{underscore}by}0.40) polycrystalline HTSC  

SciTech Connect

The influence of KClO{sub 3} addition on the AC complex susceptibility ({chi}{sub ac}) and microstructural morphology of YBCO HTSC with nominal composition Y{sub (1{minus}0.2x)}Ba{sub (2{minus}0.2x)}K{sub x}Cu{sub 3}O{sub y}(x = 0 {divided{underscore}by} 0.40) were investigated. {chi}{sub ac} was recorded as a function of temperature and of the concentration of KClO{sub 3} in various AC magnetic fields up to 19 Oe. The data were analyzed using the relation h = a(1 {minus} T{sub m}/{Tc}){sup n}. The results obtained showed that the presence of K- and Cl-containing impurities on the grain boundaries change the integranular coupling and, within certain concentration limits, improves the superconducting parameters.

Veneva, A.; Koblischka, M.R.; Sakai, Naomichi; Ogasawara, Kei; Murakami, Masato

1999-11-01

333

Interspecific interactions between the rare tooth fungi Creolophus cirrhatus, Hericium erinaceus and H. coralloides and other wood decay species in agar and wood.  

PubMed

Creolophus cirrhatus, Hericium erinaceus and H. coralloides were paired against over 20 other wood decay fungi from beech (Fagus sylvatica) covering a range of ecological strategies, on 2% malt agar (MA), 0.5% MA, 0.5% MA adjusted to -1.25 MPa by addition of KCl, 0.5% MA adjusted to pH 4 with KOH/H3PO4 and 0.5% MA under 5% O2/30% CO2 all at 20 degrees C. Creolophus cirrhatus and H. coralloides were also paired against 17 other species in wood, incubated at 20 degrees for 36-38 wk. They were average to good combatants, deadlocking with or replacing over half of the antagonists, H. erinaceus being slightly more combative than the other two species. Outcomes in wood were representative of those in agar. Abiotic conditions altered the outcomes slightly, reduced water potential favouring C. cirrhatus and H. erinaceus. Overall extension rate of C. cirrhatus and H. erinaceus often increased in the presence of antagonists. There was prolific production of fruit bodies in controls and interactions, though notably not under altered gaseous regime. Results are discussed in an ecological context. PMID:15757181

Wald, Paul; Pitkänen, Sini; Boddy, Lynne

2004-12-01

334

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)

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

Simon, A. C.

2001-12-01

335

Significantly enhancing supercapacitive performance of nitrogen-doped graphene nanosheet electrodes by phosphoric acid activation.  

PubMed

In this work, we present a new method to synthesize the phosphorus, nitrogen contained graphene nanosheets, which uses dicyandiamide to prevent the aggregation of graphene oxide and act as the nitrogen precursor, and phosphoric acid (H3PO4) as the activation reagent. We have found that through the H3PO4 activation, the samples exhibit the remarkably enhanced supercapacitive performance, and depending on the amount of H3PO4 introduced, the specific capacitance of the samples is gradually increased from 7.6 to 244.6 F g(-1). Meanwhile, the samples also exhibit the good rate capability and excellent stability (up to 10?000 cycles). Through the transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller analyses, H3PO4 treatment induced large pore volume and phosphorus related function groups in the product are assumed to response for the enhancement. PMID:24456232

Wang, Ping; He, Haili; Xu, Xiaolong; Jin, Yongdong

2014-02-12

336

Comparing different salt forms of rotigotine to improve transdermal iontophoretic delivery  

Microsoft Academic Search

The transdermal delivery of a new salt form of the dopamine agonist rotigotine, rotigotine·H3PO4 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·H3PO4 increases

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

2010-01-01

337

Textural and chemical properties of adsorbent prepared from palm shell by phosphoric acid activation  

Microsoft Academic Search

Textural and chemical characterisations of adsorbent prepared from palm shell, an abundantly available carbonaceous solid waste from palm oil processing mills in some tropical countries, by phosphoric acid (H3PO4) activation were carried out in this paper. The effects of activation temperature and H3PO4 impregnation on the textural and chemical properties of the adsorbent were investigated. Gas-phase adsorption of nitrogen dioxide

Jia Guo; Aik Chong Lua

2003-01-01

338

Corrosion behavior of borided AISI H13 hot work steel  

Microsoft Academic Search

The corrosion behavior of borided hot work steel H13 (AISI) in specific acid solutions (HCl 5 vol.%, H2SO4 5 vol.%, H3PO4 30 vol.%) was studied. Boriding was done by pack cementation. The corrosion behavior was evaluated by potentiodynamic polarization experiments and immersion corrosion tests. The borided steel showed a better corrosion behavior in H2SO4 and H3PO4 environments for short exposure

George K. Kariofillis; Grigoris E. Kiourtsidis; Dimitrios N. Tsipas

2006-01-01

339

Partial acidulation of an ‘unground’ phosphate rock: I. Preparation and characteristics  

Microsoft Academic Search

Partially acidulated phosphate rocks were prepared from unground North Carolina phsophate rock and H3PO4 by (i) mixing phosphate rock with the requisite amount of H3PO4, (ii) mixing with a portion of the acid followed by adding the remaining acid during granulation and (iii) single-step acidulation and granulation. The degrees of acidulation were 20, 30, 40 and 50%. Only 20% and

SSS Rajan

1985-01-01

340

A GaN-based two-sensor array for methane detection in an ethanol environment  

Microsoft Academic Search

We demonstrate that photoelectrochemical (PEC) etching of GaN layers in KOH or H3PO4 solutions leads to the formation of specific surface morphologies which cause the material to exhibit different sensitivities to certain gases. PEC etching in a KOH solution results in a pyramidal morphology of the layer which exhibits a high sensitivity to methane gas, whereas etching in a H3PO4-based

V. Popa; I. M. Tiginyanu; V. V. Ursaki; O. Volcius; H. Morkoç

2006-01-01

341

Rayon-based activated carbon fibers treated with both alkali metal salt and Lewis acid  

Microsoft Academic Search

Rayon precursors marinated by mixture aqueous solution containing NaCl and H3PO4 are activated by steam for manufacture of activated carbon fibers (ACF) in this work. It is interesting to find that mesopores (2nm50nm) are greatly developed on ACF surface, which indicates that NaCl+H3PO4 aqueous solution is an effectual pore size-enlarging impregnant. The influences of

Yuhan Chen; Qilin Wu; Pan Ning; Gong Jinghua; Pan Ding

2008-01-01

342

Effects of phosphoric acid treatment of titanium surfaces on surface properties, osteoblast response and removal of torque forces.  

PubMed

This study investigated the surface characteristics and biocompatibility of phosphate ion (P)-incorporated titanium (Ti) surfaces hydrothermally treated with various concentrations of phosphoric acid (H(3)PO(4)). The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, optical profilometry, contact angle and surface energy measurement and inductively coupled plasma mass spectroscopy (ICP-MS). MC3T3-E1 cell attachment, spreading, proliferation and osteoblastic gene expression on different surfaces were evaluated. The degree of bony integration was biomechanically evaluated by removal torque testing after 4 weeks of healing in rabbit tibiae. The H(3)PO(4) treatment produced micro-rough Ti surfaces with crystalline P-incorporated Ti oxide layers. High concentration H(3)PO(4) treatment (1% and 2%) produced significantly higher hydrophilic surfaces compared with low H(3)PO(4) treatment (0.5%) and untreated surfaces (P<0.01). ICP-MS analysis showed P ions were released from P-incorporated surfaces. Significant increased cell attachment (P<0.05) and notably higher mRNA expressions of Runx2, alkaline phosphatase, osteopontin and osteocalcin were observed in cells grown on P-incorporated surfaces compared with cells on untreated machined surfaces. P-incorporated surfaces showed significantly higher removal torque forces compared with untreated machined implants (P<0.05). Ti surfaces treated with 2% H(3)PO(4) showed increasing tendencies in osteoblastic gene expression and removal torque forces compared with those treated with lower H(3)PO(4) concentrations or untreated surfaces. These results demonstrate that H(3)PO(4) treatment may improve the biocompatibility of Ti implants by enhancing osteoblast attachment, differentiation and biomechanical anchorage. PMID:19819355

Park, Jin-Woo; Kim, Youn-Jeong; Jang, Je-Hee; Kwon, Tae-Geon; Bae, Yong-Chul; Suh, Jo-Young

2010-04-01

343

Structural and Optical Characterizations of Electrochemically Grown Connected and Free-Standing TiO2 Nanotube Array  

NASA Astrophysics Data System (ADS)

A TiO2 nanotube array was grown electrochemically by using single and mixed electrolyte/s with 20 V constant potential at room temperature. Anodization was carried out for 120 min using five different electrolytes, e.g., H3PO4, NH4F, HF, NH4F with H3PO4 and HF with H3PO4. Structural characterizations of the grown titania nanotubes were conducted by using x-ray diffraction and field emission scanning electron microscopy. Optical properties of the grown nanotubes were investigated through photoluminescence (PL) spectroscopy. In the case of the 4 M H3PO4 electrolyte, no perceptible growth of nanotubes was observed. The individual electrolytes of 0.3 M NH4F and 1 M HF resulted into the formation of the wall-connected nanotubes. In contrast, the mixed electrolytes comprising the strong (NH4F, HF) and weak (H3PO4) electrolytes have been found to be efficient for the growth of wall-separated titania nanotubes. The results of the PL spectroscopy have demonstrated that the free-standing nanotubes offer low PL intensity compared to its connected counterpart owing to the lower carrier recombination rate of free-standing nanotubes.

Hazra, A.; Dutta, K.; Bhowmik, B.; Manjuladevi, V.; Gupta, R. K.; Chattopadhyay, P. P.; Bhattacharyya, P.

2014-05-01

344

Physicochemical properties of phosphate ester from palm kernel oil  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

345

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

PubMed

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

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

2012-01-01

346

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

PubMed

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

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

2005-09-01

347

Physicochemical properties of phosphate ester from palm kernel oil  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

348

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

PubMed

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. PMID:16216312

Yang, John; Mosby, David

2006-07-31

349

Ab Initio Study of KCl and NaCl Clusters  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

350

KCl Bounce Coating of Glass and Polymer Microshells.  

National Technical Information Service (NTIS)

The progress that the Inertial Confinement Fusion (ICF) program has seen with increased laser energy and advances in plasma theory has pushed for improvements and advances in both target performance diagnostics and target fabrication. Many advances in tar...

G. B. DeMaggio, S. R. Murrell, H. K. Lintz, J. C. Daukas

1988-01-01

351

EQUILIBRIUM AND KINETICS OF DISPERSE DYE ADSORPTION ON ACTIVATED CARBON PREPARED FROM RATTAN SAWDUST BY CHEMICAL ACTIVATION  

Microsoft Academic Search

The liquid-phase adsorption of C.I. Disperse Orange 30 (DO30) onto activated carbon prepared from rattan sawdust by chemical activation with H3PO4. The rattan sawdust was carbonized at 500oC, 2h and impregnated ratio weight with H3PO4 at 1:4.5. The effects of various parameters such as contact time, initial DO30 concentration and pH were investigated at temperature 30±1oC. Langmuir, Freundlich, Temkin and

A. A. AHMAD; B. H. HAMEED; A. L. AHMAD

2008-01-01

352

Properties of Starches Modified by Different Acids  

Microsoft Academic Search

Starches from wheat, maize, finger millet, tapioca, green gram, chick pea, and potato were acid modified using 0.5N HCl, HNO3, H2SO4, and H3PO4 at 50°C for 1.5 h. Alkali Fluidity Number (AFN) for native starches was very low (0.3–2.5) and increased upon modification. HCl and HNO3 produced the highest AFN followed by H2SO4 and H3PO4?. For each acid, cereal and

V. Singh; S. Z. Ali

2008-01-01

353

Influence of a polycrystalline precipitation zone on the growth of single crystals using a gel method: growth of single crystals of PbHPO 4  

Microsoft Academic Search

During the growth of single crystals of PbHPO4 by interdiffusion of an aqueous solution of Pb(NO3)2 and an aqueous solution of H3PO4 contained in a methoxy-silane gel, a polycrystalline precipitation zone of PbHPO4 and Pb4(NO3)2(PO4)2 · 2H2O is generated at the Pb(NO3)2(aq)\\/H3PO4(aq, gel) interface. The main function of this precipitation zone is to maintain a low concentration of Pb2+ ions

K. Mayer; D. Woermann

1996-01-01

354

Electrostatic modification of oxide semiconductors by electric double layers of microporous SiO2-based solid electrolyte  

Microsoft Academic Search

We have studied electrostatic modulation of InGaZnO4 and indium-tin oxide (ITO) channel by using microporous SiO2-based solid electrolyte as gate dielectrics in the field-effect transistors (FETs) structure. H3PO4-treated SiO2-based solid electrolyte was found to be have a large capacitance (9.5 muF\\/cm2) due to the strong capacitive coupling by electric double layer(EDL) between H3PO4-treated solid electrolyte and active channel. High carrier

Jie Jiang; Minzhi Dai; Jia Sun; Bin Zhou; Aixia Lu; Qing Wan

2011-01-01

355

Technology development for phosphoric acid fuel cell powerplant, phase 2  

NASA Technical Reports Server (NTRS)

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.

Christner, L.

1979-01-01

356

Major element chemistry of surface- and ground waters in basaltic terrain, N-Iceland.: I. primary mineral saturation  

NASA Astrophysics Data System (ADS)

This contribution describes primary basalt mineral saturation in surface- and up to 90°C ground waters in a tholeiite flood basalt region in northern Iceland. It is based on data on 253 water samples and the mineralogical composition of the associated basalts. Surface waters are significantly under-saturated with plagioclase and olivine of the compositions occurring in the study area, saturation index (SI) values ranging from -1 to -10 and -5 to -20, respectively. With few exceptions these waters are also significantly under-saturated with pigeonite and augite of all compositions (SI = -1 to -7) and with ilmenite (SI = -0.5 to -6). The surface waters are generally over-saturated with respect to the titano-magnetite of the compositions occurring in the basalts of the study area, the range in SI being from -2 to +10. For crystalline OH-apatite, SI values in surface waters range from strong under-saturation (-10) to strong over-saturation (+5) but for crystalline F-apatite they lie in the range 0 to 15. Systematic under-saturation is, on the other hand, observed for "amorphous apatite," i.e. an apatite of the kind Clark (1955) prepared by mixing Ca(OH) 2 and H 3PO 4 solutions. Like surface waters, ground waters are under-saturated with plagioclase and olivine, its degree increasing with increasing Ca content of the plagioclase and increasing Fe content of the olivine, the SI values being -2 to -7 and 0 to -4 for the Ca-richest and Ca-poorest plagioclase, respectively, and about -3 to -18 and 0 to -15 for forsterite and fayalite, respectively. Ground waters are generally close to saturation with pigeonite and augite of all compositions. However, some non-thermal ground waters in highland areas are strongly under-saturated. Above 25°C the ground waters are ilmenite under-saturated but generally over-saturated at lower temperatures. These waters are titano-magnetite over-saturated at temperatures below 70°C, the SI values decreasing with increasing temperature from about 6 to 8 at 10°C to 0 at 70°C. The ground waters are highly over-saturated with both crystalline OH- and F-apatite, or by approximately 10 to 15 SI units but close to saturation with "amorphous apatite" containing about equal amounts of F and OH. The results presented here for the pyroxenes carry an unknown error because available thermodynamic data do not permit but a simple solid solution model for the calculation of their solubility. Published values on the dissociation constants for ferrous iron hydroxide complexes are very variable and those for ferric iron are limited. This casts an error of an unknown magnitude on the calculated SI values for all iron bearing minerals. This error may not be large for waters with a pH of less than 9 but it is apparently high for waters with a higher pH. Improved experimental data on the stability of ferrous and ferric hydrolysis constants are needed to improve the accuracy by which Fe-mineral saturation can be calculated in natural waters.

Arnórsson, Stefán; Gunnarsson, Ingvi; Stefánsson, Andri; Andrésdóttir, Audur; Sveinbjörnsdóttir, Árny E.

2002-12-01

357

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

PubMed

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

Bodénan, F; Deniard, Ph

2003-05-01

358

Comparison between phosphoric acid and hydrochloric acid in microabrasion technique for the treatment of dental fluorosis  

PubMed Central

Purpose: To compare the effectiveness of phosphoric acid (H3PO4)-pumice compound with conventional hydrochloric acid (HCl)-pumice compound in treating different severities of dental fluorosis with the microabrasion technique. Materials and Methods: Sixty-seven anterior teeth from seven patients with different severities of dental fluorosis were treated. In each patient, half of the teeth were treated with HCl-pumice compound and the other half with H3PO4-pumice compound (split-mouth design). Both treatment compounds were applied for 30-second periods and treatment continued up to 10 minutes. Before and after treatment, standardized photographs were taken. The photographs were compared by two experienced observers unaware of the modality of treatment. Two indices of aesthetics, improvement in appearance (IA) and degree of stain removal (DSR), were determined according to a visual analog scale. The inter- and intra-correlation coefficients were made; then, statistical analyses were calculated using Mann-Whitney and t-test. Results: There were no significant differences in interobserver evaluation. Improvements in aesthetic indices were observed in all fluorotic teeth by both compounds; however, the mean treatment time with HCl-pumice was significantly lower than H3PO4-pumice. Conclusion: The H3PO4-pumice compound improved aesthetic indices in fluorotic teeth similar to the HCl-pumice compound.

Bassir, Mahshid Mohammadi; Bagheri, Golnaz

2013-01-01

359

The Preparation of Some Novel Electrolytes: Synthesis of Partially Fluorinated Alkanesulfonic Acids as Potential Fuel Cell Electrolytes.  

National Technical Information Service (NTIS)

The objective of this research was to prepare some strong acids for evaluation by Fort Belvoir as potential fuel cell electrolytes. The major acid, other than phosphoric, H3PO4, currently under investigation by Fort Belvoir as a fuel cell electrolyte is T...

C. Bunyagidj H. Pietrowska M. H. Aldridge

1979-01-01

360

The Preparation of Some Novel Electrolytes: Synthesis of Partially Fluorinated Alkane Sulfonic Acids as Potential Fuel Cell Electrolytes.  

National Technical Information Service (NTIS)

The objective of this research was to prepare some strong acids for evaluation by Fort Belvoir as potential fuel cell electrolytes. The only acid other than phosphoric, H3PO4, currently under investigation by Fort Belvoir as a fuel cell electrolyte is TFM...

C. Bunyagidj M. H. Aldridge

1978-01-01

361

Deuterium and Solvent Effects on Benzaldehyde Phosphorescence.  

National Technical Information Service (NTIS)

The phosphorescence lifetime and spectra of benzaldehyde, benzaldehyde-d1 and benzaldehyde-d6 have been measured in methylcyclohexane, EPA, and 85% H3PO4 glasses at 77K. The measurements are consistent with a triplet state assignement of triplet n, pi* in...

J. Simpson H. Offen

1970-01-01

362

Chemical etching behaviors of semipolar (112[combining macron]2) and nonpolar (112[combining macron]0) gallium nitride films.  

PubMed

Wet chemical etching using hot KOH and H3PO4 solutions was performed on semipolar (112[combining macron]2) and nonpolar (112[combining macron]0) GaN films grown on sapphire substrates. An alternating KOH/H3PO4/KOH etch process was developed to control the orientation of the facets on the thin-film surface. The initial etch step in KOH produced c- and m-plane facets on the surface of both semipolar (112[combining macron]2) and nonpolar (112[combining macron]0) GaN thin-films. A second etch step in H3PO4 solution additionally exposed a (1[combining macron]1[combining macron]22[combining macron]) plane, which is chemically stable in H3PO4 solution. By repeating the chemical etch with KOH solution, the m-plane facets as seen in the original KOH etch step were recovered. The etching methods developed in our work can be used to control the surface morphologies of nonpolar and semipolar GaN-based optoelectronic devices such as light-emitting diodes and solar cells. PMID:24971494

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

2014-07-01

363

Hydrochloric Acid Digestion and Solvent Extraction of Western Phosphates.  

National Technical Information Service (NTIS)

The Bureau of Mines conducted laboratory tests to evaluate the production of high-purity H3PO4 by an HCl digestion-solvent extraction method. Both batch and bench-scale continuous tests were made. Western phosphate rock concentrates were acidulated with H...

J. T. May J. L. Reuss

1976-01-01

364

The Effect on Surface Enamel Fluoride and Dental Caries of Semi-Annual Topical Applications of 0.62 Ammonium Fluoride.  

National Technical Information Service (NTIS)

No inhibition of total caries experience could be detectd after two years as a result of semi-annual topical application of (1) 0.62M NH4F, pH 4.4, preceded by .05M H3PO4 or (2) the standard acidulated phosphate fluoride agent. There may have been a favor...

P. F. DePaola F. Bookstein S. Foley Y. Bakhos P. Soparkar

1975-01-01

365

Aqueous Trifluoromethanesulfonic Acid Fuel Cells.  

National Technical Information Service (NTIS)

Subscale hydrogen-air fuel cells were successfully operated with 6M TFMSA as the electrolyte at temperatures as high as 60 C. The fuel cell performance was enhanced over similarly loaded electrodes in H3PO4 due to the apparent improved kinetics for the ox...

M. George

1979-01-01

366

Dissolution Controlee d'UN Materiau Piezoelectrique, la Berlinite (AlPO4) (Controlled Dissolution of a Piezoelectric Material Berlinite (AlPO4)).  

National Technical Information Service (NTIS)

The results on the controlled dissolution of berlinite aimed at realizing AT high frequency (75 Hz) resonators are presented. The dissolution takes place in acid solutions (H3PO4 or H2SO4) of aluminum phosphate. The dissolution kinetics and evolution of t...

O. Cambon A. Goiffon A. Ibanez E. Philippot

1992-01-01

367

Temporal characteristics of picosecond continuum as revealed by a two-dimensional analysis of streak images  

NASA Astrophysics Data System (ADS)

A two-dimensional analysis has been made for streak images of picosecond continua generated in D 2O, CCl 4, saturated aqueous solution of KDP, H 3PO 4 and quartz block. Their pulse width and distribution of arrival time at the streak camera were determined as a function of the wavelength.

Masuhara, Hiroshi; Miyasaka, Hiroshi; Karen, Akiya; Uemiya, Taka; Mataga, Noboru; Koishi, Musubu; Takeshima, Akira; Tsuchiya, Yutaka

1983-02-01

368

New effects in the kinetics of the electrochemical oxidation of silicon  

Microsoft Academic Search

The present work describes new effects in the kinetics of the electrochemical oxidation of silicon observed recently by the author. One is the observation of very large oscillations of anodic potential during anodization of silicon in H3PO4\\/HF electrolyte and another is the effect of externally applied mechanical stress onto the kinetics of the Si anodization in concentrated and diluted HF.

Vitali Parkhutik

2000-01-01

369

Polyvinylpyrrolidone and polyethylenimine as inhibitors for the corrosion of a low carbon steel in phosphoric acid  

Microsoft Academic Search

Polarization and weight loss studies showed that both polyvinylpyrrolidonc and polyethylenimine are effective for the inhibition of low carbon steel over a wide concentration range of aqueous phosphoric acid (H3PO4) solutions. Both polymers retard the anodic and cathodic corrosion reactions with emphasis on the former. The results for uninhibited acid confirm the kinetic expression proposed by Mathur and Vasudevan.

Y. Jianguo; W. Lin; V. Otieno-Alego; D. P. Schweinsberg

1995-01-01

370

Partial acidulation of an ‘unground’ phosphate rock: II. Plant availability of phosphate  

Microsoft Academic Search

Four greenhouse experiments were conducted using three soils to determine the availability to plants of P from unground North Carolina phosphate rock (PR) treated with 20% to 50% of the H3PO4 required for complete acidulation. The influences of soil P retention, P status, the method of preparation of partially acidulated phosphate rocks (PAPRs) and the granule size of the products

SSS Rajan

1986-01-01

371

Activated carbons by pyrolysis of coffee bean husks in presence of phosphoric acid  

Microsoft Academic Search

Activated carbons (Acs) were prepared by pyrolysis of coffee bean husks in presence of phosphoric acid (chemical activities). Husks from Colombian coffee beans were impregnated with aqueous solutions of H3PO4 following a variant of the incipient wetness method. Diffenent concentrations were used to produce impregnation ratios of 30, 60, 100 and 150 wt.%. Activation was carried out under argon flow

M. C. Baquero; L. Giraldo; J. C. Moreno; F. Suárez-Garc??a; A. Mart??nez-Alonso; J. M. D. Tascón

2003-01-01

372

Observation and Study of Dislocation Etch Pits in Molecular Beam Epitaxy Grown Gallium Nitride With the Use of Phosphoric Acid and Molten Potassium Hydroxide.  

National Technical Information Service (NTIS)

Defects continue to challenge the functionality and reliability gallium nitride (GaN)-based devices. GaN grown on sapphire by molecular beam epitaxy was investigated by wet etching in hot phosphoric acid (H3PO4) and molten potassium hydroxide (KOH). Hexag...

F. Semendy U. Lee

2007-01-01

373

Field assessment of lead immobilization in a contaminated soil after phosphate application.  

PubMed

A pilot-scale field demonstration was conducted at a Pb-contaminated site to assess the effectiveness of Pb immobilization using P amendments. The test site was contaminated by past battery recycling activities, with average soil Pb concentration of 1.16%. Phosphate amendments were applied at a 4.0 molar ratio of P/Pb with three treatments: T1, 100% P from H(3)PO(4); T2, 50% from H(3)PO(4)+50% from Ca(H(2)PO(4))(2); and T3, 50% from H(3)PO(4)+5% phosphate rock. Soil samples were collected and characterized 220 days after P application. Surface soil pH was reduced from 6.45 to 5.05 in T1, to 5.22 in T2, and to 5.71 in T3. Phosphate treatments effectively transformed up to 60% of total soil Pb from the non-residual fraction (sum of water soluble and exchangeable, carbonate, Fe-Mn oxide, and organic fractions) to the residual fraction relative to the control. In addition, P treatments reduced Toxicity Characteristic Leaching Procedure (TCLP) Pb from 82 mg l(-1) to below EPA's regulatory level of 5 mg l(-1) in the surface soil. Scanning electron microscopy-energy dispersive X-ray elemental analysis and X-ray diffraction analysis indicated formation of insoluble chloropyromorphite [Pb(5)(PO(4))(3)Cl] mineral in the P-treated soils. Although H(3)PO(4) is necessary to dissolve meta-stable Pb in soil for further lead immobilization, it should be used with caution due to its potential secondary contamination. A mixture of H(3)PO(4) and Ca(H(2)PO(4))(2) or phosphate rock was effective in immobilizing Pb with minimum adverse impacts associated with pH reduction. PMID:12670762

Melamed, Ricardo; Cao, Xinde; Chen, Ming; Ma, Lena Q

2003-04-15

374

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

NASA Astrophysics Data System (ADS)

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.

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

375

Effect of Alkalized Phosphogypsum on Soil Chemical and Biological Properties  

Microsoft Academic Search

Phosphogypsum (PG) was mixed with calcium hydroxide [Ca(OH)2], ranging from 0 to 5%, to determine the optimal amount of Ca(OH)2 required to alkalize the acidity of PG. The alkalized PG by 4% of Ca(OH)2 addition was selected for field tests to evaluate the effects of alkalized PG on soil microbial, chemical properties, and yield of Chinese cabbage. Soil pH increased

Chang Hoon Lee; Byung Yeon Ha; Yong Bok Lee; Pil Joo Kim

2009-01-01

376

The effects of calcium hydroxide on hydrogen chloride emission characteristics during a simulated densified refuse-derived fuel combustion process.  

PubMed

This study investigated the effects of different calcium hydroxide (Ca(OH)(2)) addition methods on the potential for hydrogen chloride (HCl) formation in a simulated densified refuse-derived fuel (RDF-5) with single metal combustion system. These experiments were conducted at 850 degrees C with the Ca(OH)(2) spiked in the RDF-5 production or injection in the flue gas treatment system. The results indicated that the potential for HCl formation was decreased significantly by Ca(OH)(2) spiked in the RDF-5 production or injection in the flue gas treatment system. However, the Ca(OH)(2) injection method in the flue gas for HCl emission reduction was better than other method. According to the relationship between the HCl emission and amount of Ca(OH)(2) injected or spiked, it is interesting to find that when the Ca(OH)(2) injected or spiked ranged from 0% to 5%, the potential for HCl formation in the single metal combustion system decreases significantly with increasing Ca(OH)(2) injected or spiked ratio. A corresponding increase in the amount of CaCl(2) partitioned to the fly ash was observed. However, with the ratio of Ca(OH)(2) higher than 5%, the amount of HCl formation showed that no further significant variation occurred with increasing Ca(OH)(2) spiked ratio. PMID:18272287

Chiang, Kung-Yuh; Jih, Jer-Chyuan; Lin, Kae-Long

2008-08-30

377

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

PubMed

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

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

2005-02-14

378

Flame retardancy of polyaniline-deposited paper composites prepared via in situ polymerization.  

PubMed

Polyaniline-deposited paper composites doped with three inorganic acids were prepared via in situ polymerization, and their flame-retardant properties were investigated. Both the conductivity and flame retardancy of the composite increased with the increase of the amount of the polyaniline deposited. The doping acid played a very key role in both the conductivity and flame retardancy of the composite. The comprehensive properties of the composite could be improved when codoped with an equimolar mixture of H(3)PO(4) and H(2)SO(4) or H(3)PO(4) and HCl. The decay of the flame retardancy of the composite in atmosphere was due to the dedoping of the polyaniline deposited on cellulose fibers. PMID:23218317

Wu, Xianna; Qian, Xueren; An, Xianhui

2013-01-30

379

Hydrogen bonding analysis of phosphoric acid-N,N-dimethylformamide mixtures.  

PubMed

An analysis of H-bonding in phosphoric acid (H3PO4)-N,N-dimethylformamide (DMF) mixtures was performed across the full range of mixture compositions using the results from molecular dynamics simulations. The distribution of molecules according to the number of H-bonds they formed with OH groups or ?(=?) atoms of acid molecules and ?(=?) atoms of DMF molecules was calculated. The dependence of the average number of H-bonds per acid molecule on the concentration when the acid molecule acted as a proton acceptor was discerned, as were the corresponding dependences when the acid molecule acted as a proton donor towards H3PO4 and/or DMF. The dependence of the average number of H-bonds per DMF molecule (which always acted as a proton acceptor) on the concentration was also determined. PMID:24969845

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

2014-07-01

380

Deep ultraviolet enhanced wet chemical etching of gallium nitride  

NASA Astrophysics Data System (ADS)

We report a study of the ultraviolet (UV) irradiation effects on the wet chemical etching of unintentionally doped n-type gallium nitride (GaN) layers grown on sapphire substrates. When illuminated with a 253.7 nm mercury line source, etching of GaN is found to take place in aqueous phosphorus acid (H3PO4) and potassium hydroxide (KOH) solutions of pH values ranging from -1 to 2 and 11 to 15, respectively. Formation of gallium oxide is observed on GaN when illuminated in dilute H3PO4 and KOH solutions. These results are attributed to a two-step reaction process upon which the UV irradiation is shown to enhance the oxidative dissolution of GaN.

Peng, L.-H.; Chuang, C.-W.; Ho, J.-K.; Huang, C.-N.; Chen, C.-Y.

1998-02-01

381

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

SciTech Connect

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.

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

2013-02-01

382

Investigation of etch characteristics of non-polar GaN by wet chemical etching  

NASA Astrophysics Data System (ADS)

We characterized the surface defects in a-plane GaN, grown onto r-plane sapphire using a defect-selective etching (DSE) method. The surface morphology of etching pits in a-plane GaN was investigated by using different combination ratios of H 3PO 4 and H 2SO 4 etching media. Different local etching rates between smooth and defect-related surfaces caused variation of the etch pits made by a 1:3 ratio of H 3PO 4/H 2SO 4 etching solution. Analysis results of surface morphology and composition after etching by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) demonstrated that wet chemical etching conditions could show the differences in surface morphology and chemical bonding on the a-plane GaN surface. The etch pits density (EPD) was determined as 3.1 × 10 8 cm -2 by atom force microscopy (AFM).

Hsu, Hsiao-Chiu; Su, Yan-Kuin; Cheng, Shin-Hao; Huang, Shyh-Jer; Cao, Jia-Ming; Chen, Kuan-Chun

2010-11-01

383

Free-standing, erect ultrahigh-aspect-ratio polymer nanopillar and nanotube ensembles.  

PubMed

Free-standing polymer (poly(methyl methacrylate) or cyclic olefin copolymer) nanopillar and nanotube ensembles with previously unreported, ultrahigh aspect ratios (300 to >1600) were fabricated via anodic aluminum oxide (AAO) template-based methods that utilize a dilute, aqueous H3PO4 template etchant followed by freeze drying removal of the aqueous medium. Good replication of the AAO template by either solutions of the polymeric materials or molten polymer was achieved by using ultrasonic degassing and vacuum conditions. Classical surface wetting and viscoelastic fluid rheology theories were applied to explain the formation of polymer nanopillars and nanotubes in the aluminum oxide templates. The utilization of dilute H3PO4 for etching the AAO template and freeze-drying removal of the environmental liquid allows for the preparation of free-standing, erect, and ordered polymeric nanopillars or nanotubes that show much promise for use in biological microelectromechanical systems that target biological analyses. PMID:17929951

Chen, Guofang; Soper, Steven A; McCarley, Robin L

2007-11-01

384

Laboratory Synthesized Calcium Oxide and Calcium Hydroxide Grains: A Candidate to Explain the 6.8 Micron Band.  

National Technical Information Service (NTIS)

We will demonstrate that CaO and Ca(OH)2 are excellent candidates to explain the 6.8 microns feature, which is one of the most obscure features in young stellar objects. We discuss the condensation of CaO grains and the potential formation of a Ca(OH)2 su...

Y. Kimura J. A. Nuth

2005-01-01

385

Lime Stabilization: Reactions, Properties, Design, and Construction.  

National Technical Information Service (NTIS)

For many years, various forms of lime, including products with varying degrees of purity, have been utilized successfully as soil stabilizing agents. However, hydrated high calcium lime Ca(OH)2, monohydrated dolomitic lime Ca(OH)2 MgO, calcitic quicklime ...

1987-01-01

386

A general solution-chemistry route to the synthesis Li MPO 4 ( M=Mn, Fe, and Co) nanocrystals with [010] orientation for lithium ion batteries  

Microsoft Academic Search

A general and efficient solvothermal strategy has been developed for the preparation of lithium transition metal phosphate microstructures (LiMnPO4, LiFePO4, and LiCoPO4), employing ethanol as the solvent, LiI as the Li source, metal salts as the M sources, H3PO4 as the phosphorus source, and poly(vinyl pyrrolidone) (PVP) as the carbon source and template. This route features low cost, environmental benign,

Jing Su; Bing-Qing Wei; Jie-Peng Rong; Wen-Yan Yin; Zhi-Xia Ye; Xian-Qing Tian; Ling Ren; Min-Hua Cao; Chang-Wen Hu

2011-01-01

387

Chemical oxygen demand determination in environmental waters by mixed-acid digestion and single sweep polarography  

Microsoft Academic Search

A new variant of the method for chemical oxygen demand (COD; 20–1100mg O2l?1) determination in environmental waters is described. The method is based on determination of excess Cr(VI) in a mixed-acid (H3PO4–H2SO4) digestion solution by single sweep polarography instead of titrimetry; COD is measured indirectly. The reflux time is shortened to 15min by mixed-acid digestion. The effects of mixed-acid concentration,

Dezhong Dan; Fulai Dou; Dianjie Xiu; Yuanqing Qin

2000-01-01

388

Partially acidulated reactive phosphate rock (PAPR) fertilizer and its reactions in soil  

Microsoft Academic Search

PAPR was made by partial acidulation of North Carolina phosphate rock with H3PO4. The PAPRs were incubated in bands in columns of two soils of contrasting P retention. The columns were sampled after freezing and sectioning with a cryomicrotome. The movement of P in soil incubated with33P-labelled PAPR was followed by autoradiography of polished epoxy impregnated sections of the freeze-dried

D. C. Golden; R. E. White; R. W. Tillman; R. B. Stewart

1991-01-01

389

Applicability of Activated Carbon to Treatment of Waste Containing Iodine-Labeled Compounds  

Microsoft Academic Search

A timber industry waste was transformed to activated carbon by a one-step chemical activation process using H3PO4 (H). The used activated carbon (SDH) was characterized by N2 adsorption, FTIR, density, pH, point of zero charge pHpzc, moisture and ash content. Methylene blue (MB) and the iodine number were calculated by adsorption from the solution. The applicability of the different activated

H. M. H. Gad; N. R. A. El-Mouhty; H. F. Aly

2009-01-01

390

Lithium-ion insertion in anodic TiO 2 nanotubes resulting in high electrochromic contrast  

Microsoft Academic Search

The present work investigates lithium insertion into highly ordered nanotubular layers of TiO 2 and its electrochromic effects. The nanotubes were formed by anodization of titanium in 1 M (H 3PO 4) + 1 M (NaOH) + 0.5wt% HF electrolyte at 20 V. This leads to nanotubular layers with a thickness of 1 ± 0.1 ?m, individual tube diameter of

Robert Hahn; Andrei Ghicov; Hiroaki Tsuchiya; Jan M. Macak; Andres G. Muñoz; Patrik Schmuki

2007-01-01

391

Chromatographic Fingerprint Analysis of Macrothelypteris torresiana and Simultaneous Determination of Several Main Constituents by LC  

Microsoft Academic Search

A simple and reliable identification and quality control system has been developed for monitoring a herbal plant (Macrothelypteris torresiana) based on quantitative fingerprinting analysis using liquid chromatographic method with ultra-violet detector. The herbal\\u000a extract was obtained by ultrasonic-assisted extraction. The separation was performed on a Burospher-100 C18 column by gradient elution with acetonitrile and aqueous phase (containing 0.5% H3PO4, pH

Chaomei Xiong; Jinlan Ruan; Ying Tang; Yaling Cai; Wei Fang; Yong Zhu; Daonian Zhou

2009-01-01

392

Acid-etching andHydration Influence onDentin Roughness andWettability  

Microsoft Academic Search

Adhesion ofrestorative andprotective materials to dentin isanimportant requirement foroperative andpre- ventive dentistry. Wettability androughness aredentin sub- strate conditions thatarecritical toestablishing good adhesion. Thisstudy examined superficial anddeepdentin forvariations inwatercontact angle measurements and roughness forpolished, etched, dehydrated, andrehydrated states. Superficial anddeepdentin disks from6non-carious third molarswereprepared forAFM (Atomic Force Microscope) observation, roughness measurement, andcon- tactangle measurements following specific treatments: hydrated andpolished, etched (10%H3PO4),

J. I. Rosales; G. W. Marshall; S. J. Marshall; L. G. Watanabe; M. Toledanol; M. A. Cabrerizo

393

Bonding to Er-YAG-laser-treated Dentin  

Microsoft Academic Search

Er-YAG laser irradiation has been claimed to improve the adhesive properties of dentin. We tested the hypothesis that dentin adhesion is affected by Er-YAG laser conditioning. Superficial or deep dentin from human molars was: (a) acid-etched with 35% H3PO4; (b) irradiated with an Er-YAG laser (KaVo) at 2 Hz and 180 mJ, with water-cooling; and (c) laser-and acid-etched. Single Bond

L. Ceballos; M. Toledano; R. Osorio; F. R. Tay; G. W. Marshall

2002-01-01

394

Removal of reactive dye from aqueous solutions by adsorption onto activated carbons prepared from sugarcane bagasse pith  

Microsoft Academic Search

Bagasse pith, which is the main waste from sugarcane industry in Egypt, has been used as a raw material for the preparation of different activated carbons. Activated carbons were prepared from bagasse pith by chemical activation with 28% H3PO4 (AC1), 50% ZnCl2 (AC2) followed by pyrolysis at 600°C and by physical activation at 600°C in absence of air (AC3). Different

Nevine Kamal Amin

2008-01-01

395

Simultaneous removal of acetaldehyde, ammonia and hydrogen sulphide from air by active carbon impregnated with p -aminobenzoic acid, phosphoric acid and metal compounds  

Microsoft Academic Search

Simultaneous removal of acetaldehyde, ammonia, and hydrogen sulphide from air by the impregnated active carbon was studied at 25‡C. p-Aminobenzoic acid (PABA), phosphoric acid (H3PO4), and metal compound such as copper (II) chloride dihydrate (CuCl2·2H2O), copper (II) nitrate trihydrate (Cu(NO3)2·3H2O), and potassium iodide (KI) were investigated as impregnation ingredients. Acetaldehyde and ammonia were simultaneously removed from air by the active

M. Sugiura; K. Fukumoto

1994-01-01

396

Granular activated carbons from nutshells for the uptake of metals and organic compounds  

Microsoft Academic Search

Almond and pecan shells were chosen as hard, lignocellulosic precursors for the production of granular activated carbons (GACs) in order to create carbons for the adsorption of both organic compounds and metals. They were activated either chemically, with H3PO4, or physically, with CO2, under a variety of conditions. Following activation, a portion of the GACs were oxidized with air.The acid-activated

C. A. Toles; W. E. Marshall; M. M. Johns

1997-01-01

397

Effect of surface chemistry on gas-phase adsorption by activated carbon prepared from oil-palm stone with preimpregnation  

Microsoft Academic Search

Effects of surface chemistry (acidity or basicity) on gas-phase adsorption (NO2 or NH3) by activated carbons prepared from oil-palm stones pre-impregnated with various solutions (ZnCl2, H3PO4 and KOH) were studied in this paper. Textural and chemical characterizations of these activated carbons were carried out. High solid density and hardness, fairly high BET surface area and predominant microporosity (as shown in

Jia Guo; Aik Chong Lua

1999-01-01

398

A polymer electrolyte membrane for high temperature fuel cells to fit vehicle applications  

Microsoft Academic Search

Poly(tetrafluoroethylene) PTFE\\/PBI composite membranes doped with H3PO4 were fabricated to improve the performance of high temperature polymer electrolyte membrane fuel cells (HT-PEMFC). The composite membranes were fabricated by immobilising polybenzimidazole (PBI) solution into a hydrophobic porous PTFE membrane. The mechanical strength of the membrane was good exhibiting a maximum load of 35.19MPa. After doping with the phosphoric acid, the composite

Mingqiang Li; Keith Scott

2010-01-01

399

Measuring device for synchrotron X-ray imaging and first results of high temperature polymer electrolyte membrane fuel cells  

Microsoft Academic Search

In this paper, a measurement cell for recording synchrotron X-ray images of low and high temperature PEM fuel cells is described. The experimental setup allows for recording of cross-sectional images, as well as for radiograms in through-plane direction, with limited signal degradation. First results on H3PO4 concentration and distribution as a function of the operating conditions are presented.This basic cell

R. Kuhn; J. Scholta; Ph. Krüger; Ch. Hartnig; W. Lehnert; T. Arlt; I. Manke

2011-01-01

400

Acidic electroless copper deposition on aluminum-seeded ABS plastics  

Microsoft Academic Search

Copper (Cu) was successfully deposited onto aluminum (Al)-seeded acrylonitrile–butadiene–styrene (ABS) plastics in acidic electroless baths containing 15 wt.% copper sulfate and 5 wt.% of any of the acids including sulfuric acid (H2SO4), phosphoric acid (H3PO4), nitric acid (HNO3), or acetic acid (CH3COOH). Cu crystals were formed on the Al-seeded ABS surfaces deposited from all of the four acidic baths. Electroless Cu deposition

Dapeng Li; Chen-Lu Yang

2009-01-01

401

Culture of Candida in vinasse and molasses: Effect of acid and salt addition on biomass and raw protein production  

Microsoft Academic Search

Species of the genera Candida grown in vinasse and molasses were studied under the following conditions: agitation of containers, pH 4.6, culture time of 24 hours at 30°C. The greatest biomass production of C. krusei grown in vinasse was obtained with the addition of 0.1% H3PO4, and of C. guilliermondii and C. utilis with the addition 0.02% urea plus 0.03%

Sâmia Maria Tauk

1982-01-01

402

The defect distribution and chemical etching of Langasite (La 3Ga 5SiO 14) crystals grown by the Czochralski method  

Microsoft Academic Search

The defect distribution of grown Langasite crystals as different growth conditions and selective chemical etching on La3Ga5SiO14 single crystals of various etchants were investigated. The applications of piezoelectric devices were shown to be necessary to ensure a high surface finish. Colloidal silica was found to produce the best polishing effect and H3PO4-based etchants were shown in distinct selective etching effect

Il Hyoung Jung; Kwang Bo Shim; Keun Ho Auh; Tsuguo Fukuda

2000-01-01

403

Hydrothermal synthesis, morphological evolution and characterization of Na 2CoP 2O 7 crystals  

NASA Astrophysics Data System (ADS)

Na 2CoP 2O 7 crystals are synthesized by hydrothermal technique at moderate pressure-temperature conditions. The maximum degree of crystallinity is observed at the critical concentration of initial components, beyond which the crystallinity collapses sharply to a minimum. Solubility studies have revealed positive thermal coefficient of solubility in a H 3PO 4 solvent with relatively high enthalpy. DTA results revealed this compound to undergo a phase transition at 380 °C.

Gopalakrishna, G. S.; Mahesh, M. J.; Ashamanjari, K. G.; Shashidharaprasad, J.

2005-08-01

404

Impacts of Phosphate Amendments on Lead Biogeochemistry at a Contaminated Site  

Microsoft Academic Search

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,

XINDE C AO; LENA Q. M A; MING C HEN; SATYA P. S INGH; WILLIE G. H ARRIS

405

An improved polymer electrolyte-based amperometric hydrogen sensor  

Microsoft Academic Search

.  \\u000a An improved polymer electrolyte membrane (PEM) fuel cell-based amperometric hydrogen sensor that operates at room temperature\\u000a has been developed. The electrolyte used in the sensor is a PVA\\/H3PO4 blend, which is a proton-conducting solid polymer electrolyte. A thin film of palladium is used as the anode and platinum\\u000a supported on carbon as the cathode. The sensor functions as a

C. Ramesh; G. Velayutham; N. Murugesan; V. Ganesan; K. S. Dhathathreyan; G. Periaswami

2003-01-01

406

Studies on modified anode polymer hydrogen sensor  

Microsoft Academic Search

An improved polymer electrolyte membrane (PEM) fuel cell based amperometric hydrogen sensor that operates at room temperature\\u000a has been developed. The electrolyte used in the sensor is PVA\\/H3PO4 blend, which is a proton conducting solid polymer electrolyte. A blend of palladium and platinum coated on the membrane is\\u000a used as anode and platinum as cathode. The sensor functions as a

C. Ramesh; G. Velayutham; N. Murugesan; V. Ganesan; V. Manivannan; G. Periaswami

2004-01-01

407

Preparation and characterization of polyaniline\\/manganese dioxide composites via oxidative polymerization: Effect of acids  

Microsoft Academic Search

Polyaniline\\/manganese dioxide (PANI\\/MnO2) composites have been chemically prepared by oxidative polymerization of aniline in acidic medium containing MnO2 as an oxidant. The acids used were; H2SO4, HNO3, HCl, and H3PO4 The prepared composites were characterized by SEM, elemental analysis, FT-IR, XRD, TGA, and magnetic susceptibility. XRD measurements of the composites revealed that the crystal structure of incorporated MnO2 undergone a

Ali H. Gemeay; Ikhlas A. Mansour; Rehab G. El-Sharkawy; Ahmed B. Zaki

2005-01-01

408

Conceptual design of sulfur–iodine hydrogen production cycle of Korea Institute of Energy Research  

Microsoft Academic Search

The sulfur–iodine (S–I) thermochemical cycle offers a promising approach to the high efficiency production of hydrogen from nuclear power. S–I process was originally proposed by General Atomic. Especially, HI decomposition flowsheets of S–I process were proposed by several research groups. General Atomics (GA) studied I2 separation by extractive distillation using H3PO4. RWTH introduced the concept of reactive distillation. HIx stream

Won-Chul Cho; Chu-Sik Park; Kyoung-Soo Kang; Chang-Hee Kim; Ki-Kwang Bae

2009-01-01

409

Polymer based solid state electrochromic display device using PVA complex electrolytes  

Microsoft Academic Search

Electrochromic display device has been fabricated using poly vinyl alcohol (PVA) films complexed with H3PO4 and H2SO4, as electrolyte and WO3 film as electrochromic material. The device response such as colouration and bleaching times are determined from the variation of transmitted light intensity measurement at 450 nm wavelength. Various device parameters such as colouration efficiency, transmissive contrast ratio and transmittance

K. P. Singh; R. P. Singh; P. N. Gupta

1995-01-01

410

Hydroxyapatite Deposited on Flat and porous Ti  

Microsoft Academic Search

Abstract-Formation of porous Ti layer during electrochemical etching in H3PO4 + NH4F, subsequent deposition of calcium-phosphate and corrosion behavior of the materials was described. Anodic etching results in surface roughening with pits diameter in the range of 7-12 ?m. The subsequent cathodic electrochemical treatment, results in hydroxyapatite (HA) deposition. The source of Ca and P were two types of electrolytes:

J. Jakubowicz; G. Adamek

2010-01-01

411

Electrochemical Behavior of Polyaniline, Poly(o-Anisidine) and Their Copolymer Thin Films in Inorganic and Organic Supporting Electrolytes  

Microsoft Academic Search

The influence of inorganic and organic supporting electrolytes on electrochemical, optical, and conducting properties of polyaniline, poly(o-anisidine), and poly(aniline-co-o-anisidine) thin films were investigated. Homo- and copolymer thin films were synthesized electrochemically, under cyclic voltammetric conditions in aqueous solutions of inorganic acids, viz., H2SO4, HCl, HNO3, H3PO4, and HClO4 and organic acids, viz., benzoic acid, cinnamic acid, oxalic acid, malonic acid,

D. D. Borole; U. R. Kapadi; P. P. Mahulikar; D. G. Hundiwale

2005-01-01

412

Study of the hydrolysis of sugar cane bagasse using phosphoric acid  

Microsoft Academic Search

In the present work, samples of sugar cane bagasse were hydrolysed with phosphoric acid under mild conditions (H3PO4 2–6%, time 0–300min and 122°C) to study the feasibility of using the liquid phase as fermentation media. Solid yield, sugar concentrations and decomposition product concentrations were measured. The composition of hydrolysates, their purity and the ratio sugars\\/inhibitors were analyzed. Kinetic models were

Sara Gámez; Juan Jose González-Cabriales; José Alberto Ramírez; Gil Garrote; Manuel Vázquez

2006-01-01

413

Review of phosphorus acid and its salts as fertilizer materials  

Microsoft Academic Search

This is a review of the literature, recent unpublished research, and other information pertaining to the use of phosphorus acid (H3PO3) and its salts as fertilizer materials. Early studies on the potential of H3PO3 and its salts as alternative phosphate fertilizers showed that these phosphorus (P)?containing materials were not as effective as phosphoric acids (H3PO4) and its derivatives on growth

David A. Rickard

2000-01-01

414

An Improved Copper Reagent for Quantitative Densitometric Thin-Layer Chromatography of Lipids  

Microsoft Academic Search

Eleven cupric compounds were screened to determine whether a different cupric anion might give greater and more uniform charring responses with lipid classes on TLC plates than cupric acetate. A procedure was developed which used 10% CuSO4 in 8% H3PO4 as a charring reagent. Improved reproducibility of charring was obtained by temperature-programmed heating of the thin layer plates from 30

Joel Bitman; D. L. Wood

1982-01-01

415

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

416

Structure and antibacterial activity of silver-supporting activated carbon fibers  

Microsoft Academic Search

In this paper, several kinds of silver supporting activated carbon fibers (ACF-Ag) were prepared by the reduction adsorption\\u000a on activated carbon fiber (ACF) activated with steam or H3PO4 using sisal, viscose and pitch fiber as precursors. Their pore structure and surface chemistry were characterized using nitrogen\\u000a adsorption, XPS, WXRD and ICP quantitative analysis. Their antibacterial activities were tested. The results

Shuixia Chen; Jinrong Liu; Hanmin Zeng

2005-01-01

417

The use of catalytic hydrogenation to intercept carbohydrates in a dilute acid hydrolysis of biomass to effect a clean separation from lignin  

Microsoft Academic Search

Biomass carbohydrates are fractionated very cleanly (>99%) from unreacted insoluble lignin by a dilute acid hydrolysis (0.35–1.5% H3PO4), wherein the incipient aldoses are intercepted by catalytic hydrogenation (Ru\\/C) to produce a solution of C5–C6 polyols (xylitol, sorbitol) and anhydro polyols (sorbitan) in which no phenols could be detected (<100ppm). A screen removes granular catalyst and lignin is simply filtered from

J. Michael Robinson; Caroline E. Burgess; Melissa A. Bently; Chris D. Brasher; Bruce O. Horne; Danny M. Lillard; José M. Macias; Hari D. Mandal; Samuel C. Mills; Kevin D. O'Hara; Justin T. Pon; Annette F. Raigoza; Ernesto H. Sanchez; José S. Villarreal

2004-01-01

418

Variation in the FTIR spectra of a biomass under impregnation, carbonization and oxidation conditions  

Microsoft Academic Search

The FTIR spectra of untreated date pits (DP) and their H3PO4-preimpregnated sample together with their chars as well as samples subjected to different activation schemes were determined. These activated carbons were prepared using phosphoric acid, steam one and two steps and potassium hydroxide. This series of activated carbons were oxidized with HNO3 and their surface modifications were detected by using

Abdel-Nasser A. El-Hendawy

2006-01-01

419

Wastewater Treatment by Chemically Activated Carbons from Giant Reed: Effect of the Activation Atmosphere on Properties and Adsorptive Behavior  

Microsoft Academic Search

Uptake of nickel and benzene from dilute single?solute solutions, mimicking wastewater with low concentrations of heavy metals or volatile organic compounds, was examined using activated carbons with similar good surface properties (BET surface area of ?1100 m\\/g). They were developed through H3PO4 acid activation of giant reed (Arundo donax L.) under flowing air or N2. The carbons obtained in air proved

M. C. Basso; A. L. Cukierman

2006-01-01

420

Production of activated carbon from coconut shell: Optimization using response surface methodology  

Microsoft Academic Search

The production of activated carbon from coconut shell treated with phosphoric acid (H3PO4) was optimized using the response surface methodology (RSM). Fifteen combinations of the three variables namely; impregnation ratio (1, 1.5, and 2); activation time (10, 20, and 30min); and activation temperature (400, 450, and 500°C) were optimized based on the responses evaluated (yield, bulk density, average pore diameter,

M. K. B. Gratuito; T. Panyathanmaporn; R.-A. Chumnanklang; N. Sirinuntawittaya; A. Dutta

2008-01-01

421

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

PubMed Central

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.

PRADO, Maira; SIMAO, Renata Antoun; GOMES, Brenda Paula Figueiredo de Almeida

2014-01-01

422

Separation of cobalt and tungsten carbide by anodic dissolution of solid alloys in phosphoric acid  

Microsoft Academic Search

For the investigation of the anodic dissolution of electrodes made of WC?Co alloy, metallic cobalt, and tungsten carbide (W), we used a three-electrode system. A 1.25 M solution of phosphoric acid (H 3 PO 4 ) was used as a working electrolyte. As electrodes of solid alloy, we took WC?6% Co (VK-6) fillets prepared according to the standard technology of

V. V. Malyshev; A. I. Hab

2004-01-01

423

31P NMR chemical shielding tensor of 2-aminoethylphosphonic acid  

Microsoft Academic Search

The symmetric part of the 31P NMR chemical shielding tensor was determined in a single crystal of 2-aminoethylphosphonic acid (AEP). The principal values, relative to 85% H3PO4, are ?11=87.1, ?22=15.6, and ?33=?47.5 ppm. Four orientations of the chemical shielding tensor on the molecule are possible, but only one of them shows correlation with the bond directions. The two most shielded

Marie-Rose Van Calsteren; George I. Birnbaum; Ian C. P. Smith

1987-01-01

424

“Acid” pyrolysis-capillary chromatographic analysis of anionic and nonionic surfactants  

Microsoft Academic Search

A tandem “acid” pyrolysis-capillary chromatographic method for analyzing surfactants has been developed, and its application\\u000a to the more common anionic and nonionic surfactant types investigated. In this method a surfactant is mixed with an acid,\\u000a such as P2O5 or H3PO4, and dropped into a pyrolyzer attached to a capillary gas chromatograph. The resulting volatile pyrolyzate is carried into\\u000a the chromatograph

H. L. Lew

1967-01-01

425

Production of activated carbon from bagasse and rice husk by a single-stage chemical activation method at low retention times  

Microsoft Academic Search

The production of activated carbon from bagasse and rice husk by a single-stage chemical activation method in short retention times (30–60min) was examined in this study. The raw materials were subjected to a chemical pretreatment and were fed to the reactor in the form of a paste (75% moisture). Chemicals examined were ZnCl2, NaOH and H3PO4, for temperatures of 600,

Dimitrios Kalderis; Sophia Bethanis; Panagiota Paraskeva; Evan Diamadopoulos

2008-01-01

426

Phosphorus availability from partial acidulation of two phosphate rocks  

Microsoft Academic Search

Two phosphate rocks, one from Pesca (Colombia) and the other from Togo, were acidulated to various degrees with H2SO4 and H3PO4 for evaluation in varying granule size ranges. Products acidulated with H2SO4 were also prepared using different drying temperatures. Phosphorus availability was measured by dry-matter yield and P uptake in greenhouse experiments with maize.

L. L. Hammond; S. H. Chien; J. R. Polo

1980-01-01

427

Partially acidulated phosphate rocks: Controlled release phosphorus fertilizers for more sustainable agriculture  

Microsoft Academic Search

Phosphate rocks partially acidulated either with H3PO4 or H2SO4 were compared against SSP or TSP as phosphate fertilizers for permanent pasture. Eleven field trials were conducted over periods of up to 6 yrs. Fertilizers were surface applied annually. Initial soil pHw values ranged from 5.5–6.3 and Soil P retention from 25% to 97%. The PRs used for partial acidulation were

S. S. S. Rajan; M. B. O'Connor; A. G. Sinclair

1994-01-01

428

Wet-process phosphoric acid obtained from Kola apatite. Purification from sulphates, fluorine, and metals  

Microsoft Academic Search

The purification of pre-concentrated up to 80 wt.% H3PO4 phosphoric acid (PA) obtained from Kola apatite in one of the Polish plants by the wet processing route was carried out by sulphate precipitation, desorption of volatile components (SiF4, HF) and liquid–liquid extraction method using 4-methyl-2-pentanone (MIBK). The experiment was carried out on a laboratory scale. The effects of the reagent

R Kijkowska; D Pawlowska-Kozinska; Z Kowalski; M Jodko; Z Wzorek

2002-01-01

429

Nanostructured thin film formation on femtosecond laser-textured Ti–35Nb–xZr alloy for biomedical applications  

Microsoft Academic Search

The aim of this study was to investigate the nanostructured thin film formation on femtosecond (FS) laser-textured Ti–35Nb–xZr alloy for biomedical applications. The initial surface roughening treatment involved irradiation with the FS laser in ambient air. After FS laser texturing, nanotubes were formed on the alloy surface using a potentiostat and a 1M H3PO4 solution containing 0.8wt.% NaF with an

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

2011-01-01

430

Surface characteristics of HA coated Ti-Hf binary alloys after nanotube formation  

Microsoft Academic Search

Ti-Hf binary alloys contained 10%, 20%, 30% and 40% (mass fraction)Hf were manufactured in the vacuum furnace system. And then, specimens were homogenized for 24 h at 1 000 °C in argon atmosphere. The formation of oxide nanotubes was conducted by anodic oxidation on the Ti-Hf alloy in 1 mol\\/L H3PO4 electrolytes containing small amounts of NaF at room temperature.

Yong-Hoon JEONG; Won-Gi KIM; Geun-Hyeong PARK; Han-Cheol CHOE; Yeong-Mu KO

2009-01-01

431

Electrochemical characteristics of nanotubes formed on Ti–Nb alloys  

Microsoft Academic Search

Titanium and Ti alloys have been used extensively as bone-implant materials due to their high strength-to-weight ratio, good biocompatibility and excellent corrosion resistance. In this work, we have investigated the effects of the ?-stabilizing element Nb on the morphology of nanotubes formed on Ti–xNb alloys using 1.0 M H3PO4 electrolyte containing 0.8 wt.% NaF and various electrochemical methods. Oxide layers consisting of

Seung-Hyun Jang; Han-Cheol Choe; Yeong-Mu Ko; William A. Brantley

2009-01-01

432

Electrochemical corrosion behaviour of nanotubular Ti–13Nb–13Zr alloy in Ringer’s solution  

Microsoft Academic Search

Nanotubular oxide layer formation was achieved on biomedical grade Ti–13Nb–13Zr alloy using anodization technique in 1M H3PO4+0.5wt.% NaF. The as-formed and heat treated nanotubes were characterized using SEM, XRD and TEM. Corrosion behaviour of the nanotubular alloy was investigated employing potentiodynamic and potentiostatic polarization. The alloy after nanotubular oxide layer formation exhibited significantly higher corrosion current density than the bare

Viswanathan S. Saji; Han Cheol Choe

2009-01-01

433

Nanotube formation and morphology change of Ti alloys containing Hf for dental materials use  

Microsoft Academic Search

In this paper, Ti–Hf (10, 20, 30 and 40 wt.%) alloys were prepared by arc melting, and subjected to heat treatment for 24 h at 1000 °C in an argon atmosphere. Formation of surface nanotubes was achieved by anodizing a Ti–Hf alloy in 1.0 M H3PO4 electrolytes with small amounts of NaF at room temperature. Microstructures of the alloys and nanotube morphology were examined

Yong-Hoon Jeong; Kang Lee; Han-Cheol Choe; Yeong-Mu Ko; William A. Brantley

2009-01-01

434

Nanotube morphology changes for Ti–Zr alloys as Zr content increases  

Microsoft Academic Search

Nanotube morphology changes in Ti–Zr alloys as Zr content increases have been investigated. Ti–Zr (10, 20, 30 and 40 wt.%) alloys were prepared by arc melting and heat treated for 24 h at 1000 °C in an argon atmosphere. TiO2 nanotubes were formed on the Ti–Zr alloys by anodization in H3PO4 containing 0.5 wt.% NaF. Electrochemical experiments were performed using a conventional three-electrode configuration

Won-Gi Kim; Han-Cheol Choe; Yeong-Mu Ko; William A. Brantley

2009-01-01

435

Nanostructured surface changes of Ti–35Ta–xZr alloys with changes in anodization factors  

Microsoft Academic Search

The purpose of this study was to investigate the changes of the nanostructured surface of Ti–35Ta–xZr alloys for dental application resulting from changes in anodization factors. TiO2 nanotubes were formed on Ti–35Ta–xZr alloys by anodization in H3PO4-containing NaF solutions. Anodization was carried out using a scanning potentiostat. Microstructures of the alloys were examined by optical microscopy (OM), field emission scanning

Won-Gi Kim; Han-Cheol Choe; William A. Brantley

2011-01-01

436

Effects of TiN film coating on electrochemical behaviors of nanotube formed Ti xHf alloys  

Microsoft Academic Search

Ti-xHf (x=10%, 20%, 30% and 40%, mass fraction) alloys were prepared by arc melting, and the microstructure was controlled for 24 h at 1 000 °C in argon atmosphere. The formation of nanotube was conducted by anodizing on Ti-Hf alloys in 1.0 mol\\/L H3PO4 electrolytes with small amounts of NaF at room temperature. And then TiN coatings were coated by

Kang LEE; Won-Gi KIM; Joo-Young CHO; Sang-Won EUN; Han-Cheol CHOE

2009-01-01

437

Study of CdTe\\/CdS-thin films by isotope dilution, neutron activation analysis, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry  

Microsoft Academic Search

.   Thin polycrystalline CdTe films can be used as materials for solar cells. The CdTe surface is etched with H3PO4\\/HNO3 solution to remove soluble Cd compounds and to leave insoluble Te compounds on the surface and thus creating a layer between\\u000a CdTe and the electrode material. Different analytical methods have been used for studying the effect of the etching procedure

R. J. Rosenberg; R. Zilliacus; E.-L. Lakomaa; A. Rautiainen; A. Mäkelä

1996-01-01

438

TiO2 nanotubes: H+insertion and strong electrochromic effects  

Microsoft Academic Search

The present work studies H+ intercalation and electrochromic effects on anodic TiO2 nanotube layers. The nanotube layers were fabricated by anodization of titanium in 1 M (H3PO4) + 1 M (NaOH) + 0.5 wt% HF electrolyte at 20 V, this results in nanotubular layers with a thickness of 1 ± 0.1 ?m with individual tube diameter of 100 ± 10

Andrei Ghicov; Hiroaki Tsuchiya; Robert Hahn; Jan M. Macak; Andres G. Muñoz; Patrik Schmuki

2006-01-01

439

Improvement of the polishing treatment for niobium surfaces of superconducting cavity resonators  

Microsoft Academic Search

For superconducting cavities made from niobium sheet, which are interesting in the field of accelerator applications, smooth and defect free inner surfaces are needed to achieve a high unloadedQ along with high accelerating field strength. These can be obtained using chemical polishing procedures. Whereas normally a mixture of HF, HNO3, and H3PO4 is applied, we chose the known bath containing

Y. Uzel; K. Schnitzke; N. Krause

1983-01-01

440

A neutron diffraction and computer modeling study of the interatomic structure of phosphoric acid  

Microsoft Academic Search

Wide angle neutron diffraction in combination with H\\/D substitution was used to determine the inter- and intramolecular structure of 100% phosphoric acid (H3PO4, PA). From radial distribution functions gHH(r),gHX(r), and gXX(r) (where X is either O or P) the hydrogen bonds were found to be characterized by a very short O&ellip;H distance (1.54 Å). Within a molecule, the orientation of

R. Hans Tromp; Stephane H. Spieser; George W. Neilson

1999-01-01

441

A neutron diffraction and computer modeling study of the interatomic structure of phosphoric acid  

Microsoft Academic Search

Wide angle neutron diffraction in combination with H\\/D substitution was used to determine the inter- and intramolecular structure of 100% phosphoric acid (H3PO4, PA). From radial distribution functions gHH(r), gHX(r), and gXX(r) (where X is either O or P) the hydrogen bonds were found to be characterized by a very short O...H distance (1.54 Å). Within a molecule, the orientation

R. Hans Tromp; Stephane H. Spieser; George W. Neilson

1999-01-01

442

Etch rates for micromachining processing  

Microsoft Academic Search

The etch rates for 317 combinations of 16 materials (single-crystal silicon, doped, and undoped polysilicon, several types of silicon dioxide, stoichiometric and silicon-rich silicon nitride, aluminum, tungsten, titanium, Ti\\/W alloy, and two brands of positive photoresist) used in the fabrication of microelectromechanical systems and integrated circuits in 28 wet, plasma, and plasmaless-gas-phase etches (several HF solutions, H3PO4, HNO3 +H2O+NH4F, KOH,

Kirt R. Williams; Richard S. Muller

1996-01-01

443

Effect of oxidant treatment of date pit active carbons used as Pd supports in catalytic hydrogenation of nitrobenzene  

Microsoft Academic Search

Two active carbons from Algerian date pits prepared by chemical activation at moderate temperature (500–600°C) with H3PO4 and ZnCl2 and one commercial active carbon (from Darco) have been oxidized with air at different temperatures (300–450°C) and with nitric acid in severe conditions during a short time. It has been demonstrated that air treatment generates surface oxygenated groups (XPS) that have

N. Bouchenafa-Saïb; P. Grange; P. Verhasselt; F. Addoun; V. Dubois

2005-01-01

444

Molecular mass determination of polyamic acid ionic salt by size-exclusion chromatography.  

PubMed

A methodology was developed for the determination of molecular weight aveages of polyamic acid ionic salt (PAS) by size-exclusion chromatography (SEC). Polystyrene standards were used for calibration and THF-DMF 1:1 by volume containing 0.06 M LiBr and 0.06 M H3PO4 was used as the mobile phase. The proposed methodology was found to be reproducible. PMID:12456110

Krishnan, P Santhana Gopala; Veeramani, S; Vora, Rohit H; Chung, Tai-Shung; Uchimura, Shun-Ichiro; Sugitani, Hatsuo

2002-11-22

445

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

PubMed

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

Prado, Maíra; Simão, Renata Antoun; Gomes, Brenda Paula Figueiredo de Almeida

2014-06-01

446

Structural characterization of PVdF-HFP\\/PEG\\/Al 2O 3 proton conducting membranes for fuel cells  

Microsoft Academic Search

Composite polymer membranes comprising of poly(vinylidene fluoride-hexafluoro propylene)\\/alumina (PVdF-HFP\\/Al2O3) were prepared by phase inversion technique with poly(ethylene glycol) (PEG) as an additive. The prepared membranes were soaked in 6M H3PO4 and were immobilized for protonic conductivity. The morphological properties of the prepared membranes were examined by scanning electron microscopy (SEM). The infra-red spectroscopic measurements revealed the presence of phosphate anions

G. Gnana Kumar; Pil Kim; Kee suk Nahm; R. Nimma Elizabeth

2007-01-01

447

Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation  

Microsoft Academic Search

Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, XP (gH3PO4\\/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000m2\\/g) and high pore volume (up to 1.19cm3\\/g) can

Sandro Altenor; Betty Carene; Evens Emmanuel; Jacques Lambert; Jean-Jacques Ehrhardt; Sarra Gaspard

2009-01-01

448

Chemical synthesis of bone-like carbonate hydroxyapatite from hen eggshells and its characterization  

Microsoft Academic Search

Carbonate hydroxyapatite (CHAp) was synthesized from domestic hen eggshells by using three alternative wet chemical methods at room temperature. In the first method, the powdered eggshells were reacted directly with H 3PO4. In the other two methods, calcium acetate was obtained in a first step by dissolving the eggshells in acetic acid. Then, calcium acetate was reacted with Na3PO4·12H2O and

J. L. ACEVEDO-DÁVILA; J. MÉNDEZ-NONELL

449

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

PubMed

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). PMID:22917494

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

2012-10-15

450

Chemical Extraction of Arsenic from Contaminated Soil  

Microsoft Academic Search

A series of batch extraction experiments were conducted using a fortified soil with different extracting solutions such as inorganic acids (hydrochloric acid (HCl), sulfuric acid (H2SO4), phosphoric acid (H3PO4), perchloric acid (HClO4), or nitric acid (HNO3)), organic acids (acetic acid (C2H4O2), citric acid (C6H8O7)) and alkaline agent (NaOH). Various concentrations were used to investigate the removal efficiency and to optimise

M. G. M. ALAM; S. TOKUNAGA

2006-01-01

451

The effect of phosphoric acid concentration on resin tag length and bond strength of a photo-cured resin to acid-etched enamel  

Microsoft Academic Search

Objectives: To determine the relationship between depth of penetration and tensile bond strength of a photo-cured resin to phosphoric acid etched enamel, and the efficacy of enamel etchants that are less aggressive than a concentration of 10% H