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1

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

2

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. PMID:24678507

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

2014-01-01

3

Kinetic control in the CID-induced elimination of H3PO4 from phosphorylated serine probed using IRMPD spectroscopy.  

PubMed

InfraRed Multiple Photon Dissociation (IRMPD) spectroscopy was used to assay the structural features of the fragment ions resulting from the elimination of H3PO4 in the Collision-Induced Dissociation (CID) of protonated serine. The results are interpreted with the aid of density functional theory calculations. Experiment and theory point to an aziridine-ring structure, implying participation of the vicinal amino group in the formation of this species. This finding constitutes a benchmark for investigating the same process in the CID of phosphorylated peptides. PMID:24589658

Lanucara, Francesco; Chiavarino, Barbara; Scuderi, Debora; Maitre, Philippe; Fornarini, Simonetta; Crestoni, Maria Elisa

2014-04-14

4

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

5

Systematic characterization of a PBI/H3PO4 sol-gel membrane-Modeling and simulation  

NASA Astrophysics Data System (ADS)

This work presents a three-dimensional, steady-state, non-isothermal model of a high-temperature polymer-electrolyte-membrane fuel cell (HTPEMFC) using a phosphoric acid-doped polybenzimidazole (PBI/H3PO4) sol-gel membrane. The model accounts for the gold-plated copper current collector plates, the bipolar plates, all gas flow channels (flow-field), the gas diffusion layers, the reaction layers, and the membrane. Electrochemical reactions are modeled using an agglomerate approach and include the gas diffusivity and the gas solubility. The conductivity of the membrane is modeled using the Arrhenius equation to describe the temperature dependence. Finite elements are used to discretize all computational subdomains, and a commercially available code is used to solve the problem. The predicted values are compared to typical operating conditions, and a good agreement is found. The current density, the solid- and fluid-(gas)-phase temperatures and other quantities are analyzed throughout the computational subdomains. It was observed that the Arrhenius approach is valid in a certain temperature range and may overpredict the PBI/H3PO4 sol-gel membrane conductivity at higher solid-phase temperatures. Moreover, it is shown how the fluid-(gas)-phase temperature influences the solid-phase temperature and the current density distribution. Concrete values are deduced from the simulations and discussed according to experimental test.

Siegel, C.; Bandlamudi, G.; Heinzel, A.

2011-03-01

6

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

PubMed

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

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

2014-11-01

7

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 60 min, 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

8

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

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

9

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

10

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

11

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

PubMed

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

Zhao, Wenxia; Ding, Jie; Wang, Zenglin

2013-05-21

12

Role of surface reactions in the transpassive dissolution of ferrous alloys in concentrated H 3PO 4  

NASA Astrophysics Data System (ADS)

The transpassive dissolution of a range of ferrous alloys (Fe-12% Cr, Fe-12% Cr-5% Mo, Fe-25% Cr, Fe-25% Cr-10% Mo) in concentrated H 3PO 4 was studied within the frames of an investigation of electropolishing mechanisms. Measurements by the contact electric resistance (CER) technique have demonstrated that in the transpassive region, the resistance of the anodic film first decreases with increasing potential due to enhanced conductivity of that film and then increases at higher potentials, indicating transpassive film growth. The release of soluble Cr(VI) as detected by rotating ring-disc measurements is the higher, the higher the Cr content in the alloy, and further increases upon addition of 10% Mo to the Fe-Cr alloys. Impedance spectra in the transpassive region have been found to include contributions both from the anodic film and a multistep transpassive dissolution reaction at the film/solution interface. The results were interpreted using a generalised model of transpassive dissolution. The kinetic parameters of the process were determined and the influence of alloy composition on their values is discussed in relation to the processes of anodic surface treatment.

Betova, Iva; Bojinov, Martin; Tzvetkoff, Tzvety

2003-12-01

13

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

14

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

15

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

16

Magnetic and electrical properties of two polyaniline families: PANI-H3PO4 and PANI-C4H6O6  

NASA Astrophysics Data System (ADS)

We report a comparative study between two kinds of polyaniline, PANI-H3PO4 and PANI-C4H6O6. We have measured the temperature dependence of the dc-conductivity ?dc(T) and magnetic susceptibility ?T(T). The structure of polyaniline was characterized by Fourier transform infrared technique, electron-spin-resonance and x-ray diffraction. Polyaniline synthesized with phosphoric and tartaric acids leads to high magnetic susceptibility ?T (at T = 295 K) approx 10-4 emu/mol.2rings. The dc-conductivity of both kinds of PANI shows a semiconductor behavior and follows the quasi-one-dimensional variable-range-hopping model. A comparison of the magnetic susceptibility shows greater electron localization in PANI-C4H6O6, which is in agreement with the lower conductivity at room temperature for PANI-C4H6O6.

Elamin, Abdulkader M.; Zu-li, Liu; Kai-lun, Yao

1998-06-01

17

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

18

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

PubMed Central

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

Ahmad, F.; Sheha, E.

2012-01-01

19

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

20

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

21

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

22

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

23

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

PubMed Central

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

Mun, Ju-Hyun; Hwang, Hey-Zoo

2014-01-01

24

Stress-strain relationship of Ca(OH)2-activated Hwangtoh concrete.  

PubMed

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

Yang, Keun-Hyeok; Mun, Ju-Hyun; Hwang, Hey-Zoo

2014-01-01

25

COMPARATIVE SO2 REATIVITY OF CAO DERIVED FROM CACO3 AND CA(OH)2  

EPA Science Inventory

The paper gives results of a Comparison of experimental data on sulfation rates of CaO particles derived from CaC03 with those derived from Ca(OH)2 using a product layer diffusion control model differing only in the shape of the Cao grain. Both the model and the experimental data...

26

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

EPA Science Inventory

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

27

Nuclear magnetic ordering in Ca(OH)2. II. Restricted trace approximation  

E-print Network

1463 Nuclear magnetic ordering in Ca(OH)2. II. Restricted trace approximation G. D. F. van Velzen 1 er décembre 1989, révisé le 5 mars 1990, accepté le 21 mars 1990) Résumé. 2014 Les phases expérimentales antérieures. Abstract. 2014 The magnetic phases of the quasi two-dimensional proton spin system

Boyer, Edmond

28

Characteristics and reactivities of Ca(OH) 2\\/silica fume sorbents for low-temperature flue gas desulfurization  

Microsoft Academic Search

Ca(OH)2\\/silica fume sorbents were prepared with various Ca(OH)2\\/silica fume weight ratios and slurrying times at 65°C and a water\\/solid ratio of 10\\/1. Dry sorbents prepared were characterized, and their reactivities toward SO2 were measured in a differential fixed-bed reactor at the conditions similar to those in the bag filters in the dry and semidry flue gas desulfurization (FGD) processes. The

Ren-Bin Lin; Shin-Min Shih; Chiung-Fang Liu

2003-01-01

29

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

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

30

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

31

Surface coating with Ca(OH)2 for improvement of the transport of nanoscale zero-valent iron (nZVI) in porous media.  

PubMed

A novel thermal deposition method was developed to coat Ca(OH)2 on the surface of nanoscale zero-valent iron (nZVI). The nZVI particles with the Ca(OH)2 coating layer, nZVI/Ca(OH)2, had a clear core-shell structure based on the transmission electron microscopy observations, and the Ca(OH)2 shell was identified as an amorphous phase. The Ca(OH)2 coating shell would not only function as an effective protection layer for nZVI but also improve the mobility of nZVI in porous media for its use in environmental decontamination. A 10% Ca/Fe mass ratio was found to result in a proper thickness of the Ca(OH)2 shell on the nZVI surface. Based on the filtration tests in sand columns, the Ca(OH)2-based surface coating could greatly improve the mobility and transport of nZVI particles in porous media. In addition, batch experiments were conducted to evaluate the reactivity of Ca(OH)2-coated nZVI particles for the reduction of Cr(VI) and its removal from water. PMID:24292480

Wei, Cai-jie; Li, Xiao-yan

2013-01-01

32

Kinetics of dry flue gas desulfurization at low temperatures using Ca(OH) 2: competitive reactions of sulfation and carbonation  

Microsoft Academic Search

The kinetics of the sulfation and carbonation reactions of the sorbent Ca(OH)2 were investigated in an isothermal packed-bed reactor for the application to the flue gas desulfurization process at low temperatures. The reaction temperature was analyzed at three levels: 55, 65 and 75°C; the relative humidity in the range between 40 and 70% and the sorbent load in the bed

A. Garea; J. L. Herrera; J. A. Marques; A. Irabien

2001-01-01

33

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

34

[Removal of NOx by nonthermal plasma combined with CuO catalyst or in situ Ca(OH)2 absorption].  

PubMed

The removals of NO by a wire-in-tube nonthermal plasma reactor combined with catalysis or in situ chemical absorption were investigated. Experimental results show that the plasma reduction of NO was much enhanced by the CuO catalyst in the reactor. On the other hand, for the catalytic reduction of NO, the reaction temperature was effectively decreased by the pulsed corona discharge. A NO reduction of 100% by the plasma reactor combined with CuO catalyst was achieved under the operation condition of inlet NO concentration 719 mg/m3, 1% CO, pulse voltage 18 kV and reaction temperature 473 K. For plasma combined with in situ absorption, it was found that NO removal was much higher than by the reactor without Ca(OH)2 sorbent. It was demonstrated that in situ absorption of NO oxidation products of NO2 and/or NO3 by Ca(OH)2 was responsible for the promotion of NO removal. NO removal of 100% was achieved for 1050 mg/m3 NO in a gas mixture of 2% O2 and 98% N2 with a pulse voltage of 18 kV. PMID:17256589

Huang, Li-wei; Hitoki, Matsuda

2006-10-01

35

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

PubMed

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

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

2000-09-01

36

Bacterial Efficacy of Ca(oH)2 Against E.faecalis Compared with three Dental Lasers on Root Canal Dentin- An Invitro Study  

PubMed Central

Aim: The aim of this study was to evaluate bactericidal effect of Ca(OH)2 compared with 810 nm diode, 980 nm diode, and Nd:YAG lasers on root canal dentin against E.faecalis. Materials and Methods: Sixty five freshly extracted human mandibular single rooted teeth were selected for the study. The apical third of these roots was gradually enlarged until reaching the ISO 40- K file. The samples were divided into 4 groups, each containing 15 teeth and 5 teeth for control group. Group-1: 810 nm Diode; Group-2: 980 nm Diode; Group-3: Nd:YAG; Group-4: Ca(OH)2. 50?L of the E.faecalis ATCC 29212 strand was incubated in 1 mL of Brain Heart Infusion Broth (BHI) culture medium in37oC incubator for 4h. The concentration of the inoculation was then adjusted for a degree of turbidity which was adjusted to 0.5 McFarland scale. Later from the incubated broth, 10?L of E.faecalis culture was inoculated into the main canal and were sealed. Results: The incubated plates were checked for growth and the colony was counted using colony counter and the results are interpreted. There was statistically significant difference (p<0.05) amongst the Ca(OH)2 group regarding the laser groups. Conclusion: The teeth irradiated with the Nd:YAG laser had significantly higher bacterial reduction than all the other groups and the respective control groups.

Subbaiah, Rama

2014-01-01

37

Kinetic analysis of the carbonation reactions for the capture of CO 2 from air via the Ca(OH) 2–CaCO 3–CaO solar thermochemical cycle  

Microsoft Academic Search

A thermogravimetric analysis of the carbonation of CaO and Ca(OH)2 with 500ppm CO2 in air at 200–450°C is performed as part of a three-step thermochemical cycle to capture CO2 from air using concentrating solar energy. The rate of CaO-carbonation is fitted to an unreacted core kinetic model that encompasses intrinsic chemical reaction followed by intra-particle diffusion. In contrast, the Ca(OH)2-carbonation

V. Nikulshina; M. E. Gálvez; A. Steinfeld

2007-01-01

38

Thermodynamics of mixing of liquids in the system Ca 3(PO 4) 2?CaCl 2?CaF 2?Ca(OH) 2  

NASA Astrophysics Data System (ADS)

Molten calcium halide and hydroxide salts may be used as flux and reactants in determining apatite exchange equilibria and solid solution behavior. New experimental data and published phase equilibria are used to determine a thermodynamic model of melts and solids along the binary joins of the anhydrous apatite system Ca 3(PO 4) 2?CaCl 2?CaF 2?Ca(OH) 2. In this model, melt components are expressed as Ca0.5X, where X is hydroxide or a halogen, or as Ca 1.5PO 4. The derived binary interaction parameters ( WG' s) are sufficient to describe deviations from Raoultian behavior for the data. Standard state data are derived for molten Ca(OH) 2 and Ca 3(PO 4) 2, and for the intermediate compounds CaClF, CaClOH, and Ca 2PO 4Cl. Melts in the CaCl 2?CaF 2 system show ideal mixing behavior, while the calcium hydroxide-bearing molten salts form asymmetric regular solutions. The hydroxide-bearing melts show the small positive enthalpies of mixing typical for mixed-anion salts. Similar behavior is measured in simpler molten salt mixtures. The positive deviations from Raoultian behavior are not a mathematical artifact of the model. Data are less extensive for the salt-phosphate systems but cover the essential portions of the systems where salt to phosphate ratios are high. The mixtures of the molten salts and phosphates salts show large negative enthalpy interaction parameters ( WH), as is expected in eutectic systems which mix a high-melting-point crystal with a low-melting-point flux. Adequate reproduction of the data requires that some entropy interaction parameters be negative, although small. This implies the presence of ordering in the melt, which is manifested in more polymerized phosphate liquids and glasses as halogenated and hydroxylated orthophosphate and pyrophosphate species. Results of the model indicate that the quaternary system is a good choice for determination of activity-composition relations for the apatites. Comparison of common sources of standard state thermodynamic data ( ROBIE et al., 1979; JANAF, CHASE et al., 1985; CODATA, GARVIN et al., 1987) shows that the data for the salts are very similar where they are not identical. At temperatures below 900°C in the ternary systems, liquid compositions will be on or near the apatite-crystalline salt cotectics, and dissolve less than 1 mol% Ca 3(PO 4) 2. This makes CaCl 2?CaF 2 mixtures excellent candidates for determination of unambiguous apatite activity-compositional relations. Only the Ca(OH) 2 liquidus is strongly affected by the addition of phosphate, but this effect is closely described by a regular solution model.

Tacker, R. C.; Stormer, J. C., Jr.

1993-10-01

39

Geopolymer-Organic Polymer Composite Synthesized by the Interactions of H3PO4 with Metakaolinite Powders and Polyvinyl Alcohol  

Microsoft Academic Search

Metakaolinite (MK)-based geopolymer-polyvinyl alcohol (PVA) composite (GPC) was synthesized in the presence of aqueous phosphoric acid as an activator at room temperature. The microstructure and morphological changes of GPC were analyzed by means of X-ray diffraction (XRD), Fourier transform-infrared spectrometry (FT-IR), thermal analysis (DSC-TG), and scanning electron microscopy (SEM). XRD and SEM results showed that the amorphous phase, including C,

Tao Xu; Jing-Zhong Chen; Wei Han; Zhen Li; Gang Yu

2010-01-01

40

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

PubMed

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

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

2005-03-17

41

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

42

Sound velocity and internal friction of Li-doped KCl  

NASA Astrophysics Data System (ADS)

Low-frequency acoustic experiments are reported on Li-doped KCl crystals and pure KCl at temperatures between 70 mK and 30 K. The temperature dependence of the transverse sound velocity is caused by the eight-level Li-tunneling systems and their particular symmetry. Both resonant and relaxational contributions to the acoustic susceptibility can be identified. A consistent interpretation is possible for the two isotopes 6Li and 7Li.

Weiss, G.; Hübner, M.; Enss, C.

1999-03-01

43

Further studies of calcium phosphate growth on phosphorylated cotton fibres  

Microsoft Academic Search

Further studies using scanning electron microscopy\\/energy dispersive X-ray analysis (SEM\\/EDX), micro-Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and solid state magic angle spinning nuclear magnetic resonance (MAS NMR) techniques of calcium phosphate growth on Ca(OH)2-treated urea\\/H3PO3- and urea\\/H3PO4-modified cotton fibres are reported. In the case of the Ca(OH)2-treated urea\\/H3PO3-modified fibres which have been reported in an earlier paper,

M. R. Mucalo; Y. Yokogawa; T. Suzuki; Y. Kawamoto; F. Nagata; K. Nishizawa

1995-01-01

44

VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA  

E-print Network

1 VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA Rudnyi E of thermodynamic properties of the vapor and the vaporization process, coupling pressure measurements the various studies ina general way. New values for thermodynamic properties of the monomer and dimer vapor

Rudnyi, Evgenii B.

45

Molecular dynamics simulations of the melting of KCl nanoparticles  

NASA Astrophysics Data System (ADS)

Molecular dynamics (MD) simulations are used to investigate the thermodynamic properties and structural changes of KCl spherical nanoparticles at various sizes (1064, 1736, 2800, 3648, 4224 and 5832 ions) upon heating. The melting temperature is dependent on both the size and shape of KCl models, and the behaviour of the first order phase transition is also found in the present work. The surface melting found here is different from the melting phenomena of KCl models or other alkali halides studied in the past. In the premelting stage, a mixed phase containing liquid and solid ions covers the surface of nanoparticles. The only peak of heat capacity spreads out a significant segment of temperature, probably exhibiting both heterogeneous melting on the surface and homogeneous melting in the core. The coexistence of two melting mechanisms, homogeneous and heterogeneous ones, in our model is unlike those considered previously. We also found that the critical Lindemann ratio of the KCl nanoparticle becomes much more stable when the size of the nanoparticle is of the order of thousands of ions. A picture of the structural evolution upon heating is studied in more detail via the radial distribution function (RDF) and coordination numbers. Our results are in a good agreement with previous MD simulations and experimental observations.

Van Sang, Le; Thi Thuy Huong, Ta; Nguyen Tue Minh, Le

2014-10-01

46

Substituting KCl for NaCl in fresh Queso Fresco  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

47

www.kcl.ac.uk/iop/depts/biostatistics BioStatistics Forum  

E-print Network

www.kcl.ac.uk/iop/depts/biostatistics BioStatistics Forum 03/04/2012 1pm Jenny Hellier Would you CONSORT with me? #12;www.kcl.ac.uk/iop/depts/biostatistics Overview · The problem · Reporting guidelines · CONSORT · Check list and flow diagram · Extensions #12;www.kcl.ac.uk/iop/depts/biostatistics The Problem

Applebaum, David

48

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

49

Optical coatings on KCl windows for CO2 lasers.  

NASA Astrophysics Data System (ADS)

The surface of polished windows, made from ultratransparent KCl by IRA technique, has been studied by both optical microscopy and spectroscopy during various stages of coatings with a partial reflecting layer of BaF2-ZnSe. It has been found that the adherence of the coating seems to be associated to the presence on the substrate of organic molecules resulting from the diffusion oil.

Medianu, R.; Nistor, S. V.

50

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

51

www.kcl.ac.uk/iop/depts/biostatistics Clustering issues in trials  

E-print Network

14/12/2012 1 www.kcl.ac.uk/iop/depts/biostatistics Clustering issues in trials: Cluster randomised trials, therapist effects and group treatments Sabine Landau & Trudie Chalder Biostatistics and Psychological Medicine, IoP Presentation at King's Trials Partnership 12th Dec 2012 www.kcl.ac.uk/iop/depts/biostatistics

Applebaum, David

52

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

53

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

54

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

55

Growth of calcium phosphate on phosphorylated chitin fibres.  

PubMed

Calcium phosphate growth on chitin phosphorylated fibres was studied using scanning electron microscopy and energy dispersive X-ray analysis (SEM, EDX), micro-Fourier transform infrared spectroscopy (FTIR), and solid state magic angle spinning nuclear magnetic resonance (MAS NMR) techniques. The C6 chemical shift positions of 13C MAS NMR in the chitin fibres phosphorylated using urea and H3PO4 are obvious indicating that phosphorylation takes place not in the C1 but in the C6 region. Micro-FTIR and 31P MAS NMR suggested that ammonium hydrogen phosphate formed during the phosphorylation procedure. Chitin fibres phosphorylated using urea and H3PO4 and then soaked in saturated Ca(OH)2 solution at ambient temperature, which lead to the formation of thin coatings formed by partial hydrolysis of the PO4 functionalities, were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5xSBF solution for as little as one day. The thin layer after Ca(OH)2 treatment functioned as a nucleation layer for further calcium phosphate deposition after soaking in 1.5xSBF solution. EDX-measured Ca : P ratios of the coatings of Ca(OH)2-treated phosphorylated chitin in 1.5xSBF solution suggested that calcium-deficient apatite was formed. PMID:15348722

Yokogawa, Y; Paz Reyes, J; Mucalo, M R; Toriyama, M; Kawamoto, Y; Suzuki, T; Nishizawa, K; Nagata, F; Kamayama, T

1997-07-01

56

Two-dimensional ultravioletray sensor utilizing photostimulated luminescence in Eu-doped KCl phosphors  

NASA Astrophysics Data System (ADS)

An efficient photostimulated luminescence (PSL) with a peak at about 420 nm is observed by stimulating ultra-violet (UV)-ray-irradiated europium-doped potassium chloride (KCl:Eu) crystalline phosphor with 560 - 580 nm light. The excitation and emission mechanism for the 420 nm PSL in UV-ray irradiated KCl:Eu phosphors are proposed. It is found that the PSL intensity increased with increasing irradiation dose of UV-ray, which indicating that the KCl:Eu is one of the most attractive candidates for two-dimensional UV-ray imaging sensor utilizing PSL phenomenon.

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

1994-07-01

57

Neuronal K-Cl Cotransporter : Transcriptional Mechanisms of KCC2 Gene Regulation.  

E-print Network

??K-Cl cotransporter 2 (KCC2) maintains a low intracellular Cl concentration required for fast hyperpolarizing responses of neurons to classical inhibitory neurotransmitters ?-aminobutyric acid (GABA) and… (more)

Uvarov, Pavel

2010-01-01

58

Solubility of NaCl and KCl in aqueous HCl from 20 to 85??C  

USGS Publications Warehouse

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

Potter, R.W., II; Clynne, M.A.

1980-01-01

59

KCl Mediates K+ Channel-Activated Mitogen-Activated Protein Kinases Signaling in Wound Healing  

PubMed Central

Background Wound healing is an interaction of a complex signaling cascade of cellular events, including inflammation, proliferation, and maturation. K+ channels modulate the mitogen-activated protein kinase (MAPK) signaling pathway. Here, we investigated whether K+ channel-activated MAPK signaling directs collagen synthesis and angiogenesis in wound healing. Methods The human skin fibroblast HS27 cell line was used to examine cell viability and collagen synthesis after potassium chloride (KCl) treatment by Cell Counting Kit-8 (CCK-8) and western blotting. To investigate whether K+ ion channels function upstream of MAPK signaling, thus affecting collagen synthesis and angiogenesis, we examined alteration of MAPK expression after treatment with KCl (channel inhibitor), NS1619 (channel activator), or kinase inhibitors. To research the effect of KCl on angiogenesis, angiogenesis-related proteins such as thrombospondin 1 (TSP1), anti-angiogenic factor, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), pro-angiogenic factor were assayed by western blot. Results The viability of HS27 cells was not affected by 25 mM KCl. Collagen synthesis increased dependent on time and concentration of KCl exposure. The phosphorylations of MAPK proteins such as extracellular-signal-regulated kinase (ERK) and p38 increased about 2.5-3 fold in the KCl treatment cells and were inhibited by treatment of NS1619. TSP1 expression increased by 100%, bFGF expression decreased by 40%, and there is no significant differences in the VEGF level by KCl treatment, TSP1 was inhibited by NS1619 or kinase inhibitors. Conclusions Our results suggest that KCl may function as a therapeutic agent for wound healing in the skin through MAPK signaling mediated by the K+ ion channel. PMID:25606484

Shim, Jung Hee; Lim, Jong Woo; Kim, Byeong Kyu; Park, Soo Jin; Kim, Suk Wha

2015-01-01

60

Effect of Polymers on the Rheological Properties of KCl\\/Polymer Type Drilling Fluids  

Microsoft Academic Search

In the course of this research, the effect of two polymers (xanthan gum and polyanionic cellulose) on the rheological properties of KCl\\/polymer type drilling fluids was investigated. Non-Newtonian drilling fluids are conventionally characterized by rheological models (Bingham Plastic, Power Law, Casson, Herchel-Bulkley and Robertson-Stiff). In this research, forty-five KCl\\/polymer data sets of varying compositions are prepared. Polymer addition to the

MUSTAFA VERSAN KOK; TOLGA ALIKAYA

2005-01-01

61

Radiation effects on beta 10.6 of pure and europium doped KCl  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

62

Volume-Sensitive K+/Cl? Cotransport in Rabbit Erythrocytes  

PubMed Central

The kinetics of activation and inactivation of K+/Cl? cotransport (KCC) have been measured in rabbit red blood cells for the purpose of determining the individual rate constants for the rate-limiting activation and inactivation events. Four different interventions (cell swelling, N-ethylmaleimide [NEM], low intracellular pH, and low intracellular Mg2+) all activate KCC with a single exponential time course; the kinetics are consistent with the idea that there is a single rate-limiting event in the activation of transport by all four interventions. In contrast to LK sheep red cells, the KCC flux in Mg2+-depleted rabbit red cells is not affected by cell volume. KCC activation kinetics were examined in cells pretreated with NEM at 0°C, washed, and then incubated at higher temperatures. The forward rate constant for activation has a very high temperature dependence (Ea ? 32 kCal/mol), but is not affected measurably by cell volume. Inactivation kinetics were examined by swelling cells at 37°C to activate KCC, and then resuspending at various osmolalities and temperatures to inactivate most of the transporters. The rate of transport inactivation increases steeply as cell volume decreases, even in a range of volumes where nearly all the transporters are inactive in the steady state. This finding indicates that the rate-limiting inactivation event is strongly affected by cell volume over the entire range of cell volumes studied, including normal cell volume. The rate-limiting inactivation event may be mediated by a protein kinase that is inhibited, either directly or indirectly, by cell swelling, low Mg2+, acid pH, and NEM. PMID:10578012

Jennings, Michael L.

1999-01-01

63

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. PMID:23034386

Antrobus, Shane P.; Lytle, Christian

2012-01-01

64

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

65

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

PubMed

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

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

2015-01-01

66

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

PubMed Central

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

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

2015-01-01

67

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

2014-09-01

68

First Principles Phase Diagram Calculations for the System NaCl-KCl: the role of excess vibrational entropy.  

E-print Network

First Principles Phase Diagram Calculations for the System NaCl-KCl: the role of excess vibrational- and without an approximation for the excess vibrational entropy (SV IB). Including SV IB dramatically improvesK}Calc. Key words: NaCl-KCl; First Principles; Phase diagram calculation; Excess vibrational entropy

Burton, Benjamin P.

69

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. PMID:24204364

Oren, Aharon

2013-01-01

70

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

PubMed

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

Oren, Aharon

2013-01-01

71

Deferiprone therapy in homozygous human ?-thalassemia removes erythrocyte membrane free iron and reduces KCl cotransport activity  

Microsoft Academic Search

Deposition of free iron is a characteristic feature of ?-thalassemia (?-thal) red blood cells believed to play an important role in the generation of oxidative injury to the cell membrane. Increased red blood cell KCl cotransport, reduced K content, and cell dehydration are also found in ?-thal red blood cells. It is not known, however, whether deposition of free iron

Lucia De Franceschi; Oded Shalev; Antonio Piga; Montessar Collell; Oliviero Olivieri; Roberto Corrocher; Robert P. Hebbel; Carlo Brugnara

1999-01-01

72

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

73

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

PubMed

Excessive intake of NaCl has been associated with the increased risk of several diseases, particularly hypertension. Strategies to reduce sodium intake include substitution of NaCl with other salts, such as KCl. In this study, the effects of NaCl reduction and its substitution with KCl on cell membranes of a cheese starter bacterium (Lactococcus lactis ssp. lactis), probiotic bacteria (Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus casei), and a pathogenic bacterium (Escherichia coli) were investigated using Fourier-transform infrared (FTIR) spectroscopy. A critical NaCl concentration that inhibited the viability of E. coli without affecting the viability of probiotic bacteria significantly was determined. To find the critical NaCl concentration, de Man, Rogosa, and Sharpe (MRS) broth was supplemented with a range of NaCl concentrations [0 (control), 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0%], and the effect on cell viability and FTIR spectra was monitored for all bacteria. A NaCl concentration of 2.5% was found to be the critical level of NaCl to inhibit E. coli without significantly affecting the viability of most of the probiotic bacteria and the cheese starter bacterium. The FTIR spectral analysis also highlighted the changes that occurred mainly in the amide regions upon increasing the NaCl concentration from 2.5 to 3.0% in most of the bacteria. Escherichia coli and B. longum were more sensitive to substitution of NaCl with KCl, compared with Lb. acidophilus, Lb. casei, and Lc. lactis ssp. lactis. To evaluate the effect of substitution of NaCl with KCl, substitution was carried out at the critical total salt concentration (2.5%, wt/vol) at varying concentrations (0, 25, 50, 75, and 100% KCl). The findings suggest that 50% substitution of NaCl with KCl, at 2.5% total salt, could inhibit E. coli without affecting the probiotic bacteria. PMID:25064650

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

2014-10-01

74

Electrochemical formation of uranium-zirconium alloy in LiCl-KCl melts  

NASA Astrophysics Data System (ADS)

Since zirconium is considered an electrochemically active species under practical conditions of the electrorefining process, it is crucial to understand the electrochemical behavior of zirconium in LiCl-KCl melts containing actinide ions. In this study, the electrochemical codeposition of uranium and zirconium on a solid cathode was performed. It was found that the ?-(U, Zr) phase, which is the only intermediate phase of the uranium-zirconium binary alloy system, was deposited on a tantalum substrate by potentiostatic electrolysis at -1.60 V (vs. Ag +/Ag) in LiCl-KCl melts containing 0.13 in mol% UCl 3 and 0.23 in mol% ZrCl 4 at 773 K. To our knowledge, this is the first report on the electrochemical formation of the ?-(U, Zr) phase. The relative partial molar properties of uranium in the ?-(U, Zr) phase were evaluated by measuring the open-circuit-potentials of the electrochemically prepared ?-phase electrode.

Murakami, Tsuyoshi; Kato, Tetsuya; Kurata, Masaki; Yamana, Hajimu

2009-11-01

75

Infrared and Raman spectra of [Re(CN)5NO]3- complex isolated in KCl matrix  

NASA Astrophysics Data System (ADS)

We report here the infrared and Raman spectra of [Re(CN)5NO]3- complex as guest diluted in the KCl crystal lattice. According to the chemical analysis, the anion concentration in the KCl host matrix is in excess of 2% (in mole). The solid state Raman spectrum of this complex is reported for the first time. The information obtained from the relative intensities of infrared and Raman bands affords a reexamination of vibration mode assignments. The observed bands splitting may be explained by the interactions of the guest complex with the host lattice, including the ways in which the K+ vacancies are distributed around [Re(CN)5NO]3- to achieve lattice charge neutrality.

Verón, M. G.; Castañeda Trujillo, L. D.; Piro, O. E.; Güida, J. A.

2014-11-01

76

Growth mechanism of long chain molecular crystals on KCl substrate due to annealing  

NASA Astrophysics Data System (ADS)

Long chain compound, calcium stearate ((CH 3(CH 2) 16COO) 2Ca), is deposited on an air-cleaved KCl (001) surface kept at 25°C in 1 x 10 -4 Pa with an average thickness of 1nm. After deposition, the films are annealed at different temperatures between 30 and 120°C for 5-120 min. As-deposited films consist of slender crystallites with a length of 0.5 ?m, in which molecules align along the <110> directions of KCl to grow epitaxially. Although the crystallites annealed at less than 50°C grow to be with a length of 1-5 ?m, they annealed above 80°C change to plate films. The growth mechanism of slender crystals and dynamics of molecular orientation change are thermodynamically discussed.

Yamanaka, Mikihiro; Mimura, Kohji; Yase, Kiyoshi; Sato, Kiyotaka; Inaoka, Kimio

1993-03-01

77

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

78

Electrochemical behavior of actinide ions in LiCl–KCl eutectic melts  

Microsoft Academic Search

The electrodeposition and dissolution of uranium and plutonium in LiCl–KCl eutectic salt on tungsten and molybdenum working electrodes were investigated by cyclic voltammetry at 723, 773 and 823K. It is suggested from the voltammograms that the electrodeposition and dissolution of U and Pu, U3+\\/U and Pu3+\\/Pu, may be quasi-reversible, while the redox reaction of U4+\\/U3+ is reversible. The adsorption and

O. Shirai; T. Iwai; Y. Suzuki; Y. Sakamura; H. Tanaka

1998-01-01

79

Electrolysis of Burnup-Simulated Uranium Nitride Fuels in LiCl-KCl Eutectic Melts  

Microsoft Academic Search

The electrochemical behavior of burnup-simulated uranium nitride fuels containing representative solid fission product elements, UN+Mo (Mo = 2.84 wt%), UN+Pd (Pd = 4.6 wt%) and (U, Nd)N (NdN = 8.0 wt%), was investigated in the molten LiCl-KCl eutectic salt with 0.54 wt% UCl3 in order to clarify the effects of fission products on the dissolution of actinide nitrides and the

Takumi SATOH; Takashi IWAI; Yasuo ARAI

2009-01-01

80

First-principles super-cell investigation of the rattling effect in Li-doped KCl  

Microsoft Academic Search

We have studied by the first-principles total energy method the off-center instability of a substitutional Li impurity in KCl. We report here the results of super-cell calculations of the energy associated with displacing the Li along , and directions relative to the K vacancy. To understand the influence of relaxations, we performed three levels of relaxations—only first nearest neighbors of

Xing Gao; Murray S Daw

2009-01-01

81

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

NASA Astrophysics Data System (ADS)

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

Safonov, O.

2012-04-01

82

Molecular cloning and functional characterization of KCC3, a new K-Cl cotransporter.  

PubMed

We isolated and characterized a novel K-Cl cotransporter, KCC3, from human placenta. The deduced protein contains 1,150 amino acids. KCC3 shares 75-76% identity at the amino acid level with human, pig, rat, and rabbit KCC1 and 67% identity with rat KCC2. KCC3 is 40 and 33% identical to two Caenorhabditis elegans K-Cl cotransporters and approximately 20% identical to other members of the cation-chloride cotransporter family (CCC), two Na-K-Cl cotransporters (NKCC1, NKCC2), and the Na-Cl cotransporter (NCC). Hydropathy analysis indicates a typical KCC topology with 12 transmembrane domains, a large extracellular loop between transmembrane domains 5 and 6 (unique to KCCs), and large NH(2) and COOH termini. KCC3 is predominantly expressed in kidney, heart, and brain, and is also expressed in skeletal muscle, placenta, lung, liver, and pancreas. KCC3 was localized to chromosome 15. KCC3 transiently expressed in human embryonic kidney (HEK)-293 cells fulfilled three criteria for increased expression of K-Cl cotransport: stimulation of cotransport by swelling, treatment with N-ethylmaleimide, or treatment with staurosporine. PMID:10600773

Race, J E; Makhlouf, F N; Logue, P J; Wilson, F H; Dunham, P B; Holtzman, E J

1999-12-01

83

Interfacial tension between aluminum and NaCl-KCl-based salt systems  

NASA Astrophysics Data System (ADS)

Aluminum scrap is frequently remelted under a NaCl-KCl based salt flux cover to prevent oxidation, to aid in the stripping of oxide films, and to improve drop coalescence. In this process, the interfacial tension between the aluminum metal and the salt flux plays an important role. However, the measurement of interfacial tensions at high temperature is difficult and prone to errors. Therefore, an interfacial tension model, presented in this article, has been developed. The interfacial tension between aluminum and NaCl-KCl based melts does not change with the addition of chlorides or with variations in the composition of the NaCl-KCl melt. On the other hand, the addition of fluorides decreases the interfacial tension to various extents due to the adsorption of sodium and/or potassium at the interface. Addition of AlF3 is the least effective; additions of LiF, MgF2, CaF2, BaF2, or SrF2 are moderately effective; and additions of NaF or KF are the most effective in lowering the interfacial tension.

Roy, Raja R.; Utigard, Torstein A.

1998-08-01

84

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

85

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

SciTech Connect

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

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

2010-09-01

86

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

87

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

88

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

1976-01-01

89

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

90

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

91

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

92

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

SciTech Connect

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

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

1999-07-14

93

Chemical Crosslinking Studies with the Mouse Kcc1 K-Cl Cotransporter  

PubMed Central

Oligomerization, function, and regulation of unmodified mouse Kcc1 K-Cl cotransporter was studied by chemical crosslinking. Treatment of Xenopus oocytes and 293T cells expressing K-Cl cotransporter Kcc1 with several types of chemical cross-linkers shifted Kcc1 polypeptide to higher molecular weight forms. More extensive studies were performed with the amine-reactive disuccinyl suberate (DSS) and with the sulfhydryl-reactive bis-maleimidohexane (BMH). Kcc1 cross-linking was time-dependent in intact oocytes, and was independent of protein concentration in detergent lysates from oocytes or 293T cells. Kcc1 crosslinking by the cleavable cross-linker DTME was reversible. The N-terminal and C-terminal cytoplasmic tails of Kcc1 were not essential for Kcc1 crosslinking. PFO-PAGE and gel filtration revealed oligomeric states of uncrosslinked KCC1 corresponding in mobility to that of cross-linked protein. DSS and BMH each inhibited KCC1-mediated 86Rb+ uptake stimulated by hypotonicity or by N-ethylmaleimide (NEM) without reduction in nominal surface abundance of KCC1. These data add to evidence supporting the oligomeric state of KCC polypeptides. PMID:19380103

Casula, Sabina; Zolotarev, Alexander S.; Stuart-Tilley, Alan K.; Wilhelm, Sabine; Shmukler, Boris E.; Brugnara, Carlo; Alper, Seth L.

2009-01-01

94

Chemical crosslinking studies with the mouse Kcc1 K-Cl cotransporter.  

PubMed

Oligomerization, function, and regulation of unmodified mouse Kcc1 K-Cl cotransporter were studied by chemical crosslinking. Treatment of Xenopus oocytes and 293T cells expressing K-Cl cotransporter Kcc1 with several types of chemical cross-linkers shifted Kcc1 polypeptide to higher molecular weight forms. More extensive studies were performed with the amine-reactive disuccinyl suberate (DSS) and with the sulfhydryl-reactive bis-maleimidohexane (BMH). Kcc1 cross-linking was time-dependent in intact oocytes, and was independent of protein concentration in detergent lysates from oocytes or 293T cells. Kcc1 cross-linking by the cleavable cross-linker DTME was reversible. The N-terminal and C-terminal cytoplasmic tails of Kcc1 were not essential for Kcc1 crosslinking. PFO-PAGE and gel filtration revealed oligomeric states of uncrosslinked KCC1 corresponding in mobility to that of cross-linked protein. DSS and BMH each inhibited KCC1-mediated (86)Rb(+) uptake stimulated by hypotonicity or by N-ethylmaleimide (NEM) without reduction in nominal surface abundance of KCC1. These data add to evidence supporting the oligomeric state of KCC polypeptides. PMID:19380103

Casula, Sabina; Zolotarev, Alexander S; Stuart-Tilley, Alan K; Wilhelm, Sabine; Shmukler, Boris E; Brugnara, Carlo; Alper, Seth L

2009-01-01

95

Epitaxy of ionic insulators on a vicinal metal substrate: KCl and RbI on Cu(211)  

NASA Astrophysics Data System (ADS)

Ultrathin epitaxial films of the ionic insulators KCl and RbI on Cu(211) were investigated by high-resolution low-energy electron diffraction (SPALEED). The Cu template employed is a vicinal surface which consists of (111) terraces separated by intrinsic monatomic (100) steps along the [011¯] direction (step distance 6.25 Å). The resulting uniaxial substrate corrugation forces row matching between the intrinsic step separation and the characteristic lattice parameters along low-indexed azimuthal directions of the alkali halide layer. In this way, single-crystalline (100)-terminated films whose azimuthal orientations correspond to KCl[010]?Cu[011¯] and RbI[011]?Cu[011¯], respectively, are obtained.

Fölsch, S.; Helms, A.; Rieder, K. H.

2000-08-01

96

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). PMID:24926102

Benisek, Artur; Dachs, Edgar

2013-01-01

97

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

SciTech Connect

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

Lee, Sung Ho; Lee, Hansoo; Kim, In Tae; Kim, Jeong-Guk [Korea Atomic Energy Research Institute, 1045 Daedeok-daaro, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

2013-07-01

98

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

99

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

PubMed

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

Ruby Nirmala, L; Thomas Joseph Prakash, J

2013-02-01

100

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

NASA Astrophysics Data System (ADS)

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

Ruby Nirmala, L.; Thomas Joseph Prakash, J.

2013-02-01

101

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

102

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

103

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

104

An investigation of ruthenium coating from LiCl-KCl eutectic melt  

NASA Astrophysics Data System (ADS)

In this study, electrodeposition of ruthenium (Ru) from LiCl-KCl eutectic melt was investigated in a systematic manner and the effects of process parameters namely current density, time and agitation of electrolyte on the thickness and morphology of Ru layer were explored. The presence of Ru on graphite substrates was confirmed by thin film X-ray diffraction method. The Ru coatings formed at all electrodeposition conditions appeared as a white/gray deposit. The typical "faceted structure" was observed on the surface of Ru deposited at 3 and 7 mA/cm2. Fracture cross-section examinations revealed the columnar morphology of Ru which was twinned with boundaries. The smooth appearance of Ru coating became uneven and rough with coarse nodules at 12 mA/cm2. The thickness of Ru increased with increasing both current density and time at stationary electrodeposition conditions. A dense and 7.5 ?m thick Ru coating was possible to grow on graphite without any agitation at 3 mA/cm2 for 2 h. The highest cathodic current efficiency (?), 99.68%, was achieved at 3 mA/cm2 after 2 h of electrodeposition time with the rotating cathode speed of 50 rpm. The cross sectional micro-indentation studies indicated that the Ru layer has hardness as high as 450 ± 10 HV.

Kartal Sireli, G.

2014-10-01

105

NONOates regulate KCl cotransporter-1 and -3 mRNA expression in vascular smooth muscle cells.  

PubMed

Nitric oxide (NO) donors regulate KCl cotransport (KCC) activity and cotransporter-1 and -3 (KCC1 and KCC3) mRNA expression in sheep erythrocytes and in primary cultures of rat vascular smooth muscle cells (VSMCs), respectively. In this study, we used NONOates as rapid and slow NO releasers to provide direct evidence implicating NO as a regulator of KCC3 gene expression at the mRNA level. In addition, we used the expression of KCC3 mRNA to further investigate the mechanism of action of these NO donors at the cellular level. Treatment of VSMCs with rapid NO releasers, like NOC-5 and NOC-9, as well as with the direct NO-independent soluble guanylyl cyclase (sGC) stimulator YC-1, acutely increased KCC3 mRNA expression in a concentration- and time-dependent manner. The slow NO releaser NOC-18 had no effect on KCC3 gene expression. A specific NO scavenger completely prevented the NONOate-induced KCC3 mRNA expression. Inhibition of sGC with LY-83583 blocked the NONOate- and YC-1-induced KCC3 mRNA expression. This study shows that in primary cultures of rat VSMCs, the fast NO releasers NOC-9 and NOC-5, but not the slow NO releaser NOC-18, acutely upregulate KCC3 mRNA expression in a NO/sGC-dependent manner. PMID:12521940

Di Fulvio, Mauricio; Lauf, Peter K; Shah, Shalin; Adragna, Norma C

2003-05-01

106

K+–Cl? cotransport mediates the bactericidal activity of neutrophils by regulating NADPH oxidase activation  

PubMed Central

Neutrophilic phagocytosis is an essential component of innate immunity. During phagocytosis, the generation of bactericidal hypochlorous acid (HOCl) requires the substrates, Cl? and superoxide produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to kill the internalized pathogens. Here we show that the neutrophilic K+–Cl? cotransporter (KCC) constitutes a Cl? permeation pathway and mediates the bactericidal activity by regulating NADPH oxidase activation. Dihydroindenyloxy alkanoic acid (DIOA), a KCC inhibitor, suppressed the toxin- or chemical-induced efflux of 36Cl? or 86Rb+, and diminished the production of superoxide in human and murine neutrophils. Inhibition of KCC activity or knockdown of KCC expression, in particular KCC3, reduced the phosphorylation as well as the membrane recruitment of oxidase components. Activated neutrophils displayed a significant colocalization of KCC3 and early endosomal marker, indicating that KCC3 could be localized on the phagosomes once neutrophils are activated. The NADPH oxidase activity and the phosphorylation level of oxidase component were 50% lower in the neutrophils isolated from KCC3?/? mice than in the neutrophils isolated from KCC3+/+ mice. Mortality rate after intraperitoneal challenge with Staphylococcus aureus was higher in KCC3?/? mice, and the bacterial clearance was impaired in the survivors. We conclude that, in activated neutrophil, NADPH oxidase complexes are associated with KCC3 at the plasma membrane and are internalized to form phagosomes, where KCC activity and expression level affect the production of oxidants. PMID:22526882

Sun, Yuan-Ting; Shieh, Chi-Chang; Delpire, Eric; Shen, Meng-Ru

2012-01-01

107

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

NASA Astrophysics Data System (ADS)

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

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

1983-12-01

108

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

109

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

Microsoft Academic Search

The electrolysis of burnup-simulated uranium nitride, UN, containing representative solid fission product elements (Mo, Pd, Nd) was investigated in the molten LiCl-KCl eutectic salt with 0.54 wt% UCl from the view point of application of pyrochemical reprocessing to nitride fuel cycle. It was found from cyclic voltammetry and anodic polarization curve measurement that anodic dissolution of UN began at about

Takumi Satoh; Takashi Iwai; Yasuo Arai

2007-01-01

110

Physical chemistry of molten-salt batteries. Current-induced composition gradients in molten LiCl-KCl  

Microsoft Academic Search

Current induced composition gradients were predicted in mixed molten salt battery electrolytes. Composition shifts, if large enough, can produce significant deleterious effects, such as solid phase precipitation in or near the electrodes of molten salt batteries, including the LiAl\\/LiCl-KCl\\/Fe-S sub x battery. Quantitative measurements are needed to determine the extent of the gradients and to find means to reduce them.

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

1982-01-01

111

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

SciTech Connect

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

Satoh, Takumi; Iwai, Takashi; Arai, Yasuo [Japan Atomic Energy Agency, Narita-cho, Oarai-machi, Higashiibaraki-gun, Ibaraki-ken, 311-1393 (Japan)

2007-07-01

112

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

113

Investigation of a LiCl-KCl-UCl3 system using a combination of X-ray diffraction and differential thermal analyses  

NASA Astrophysics Data System (ADS)

Electrorefining is one of the main steps in pyroreprocessing where spent nuclear fuels are recycled. Electrorefining is conducted in a molten salt of a LiCl-KCl eutectic (59:41 mol%) containing actinide chlorides (AnCl3) at 773 K. In order to operate and maintain the electrorefiner, it is necessary to accumulate fundamental data on the LiCl-KCl-AnCl3 salt, such as its melting point. In this study, based on X-ray diffraction and differential thermal analyses, partial phase diagrams of (LiCl-KCl)eut.-UCl3 pseudo-binary and LiCl-KCl-UCl3 systems, in which the UCl3 concentration was up to 20 mol%, were developed.

Nakayoshi, Akira; Kitawaki, Shinichi; Fukushima, Mineo; Murakami, Tuyoshi; Kurata, Masaki

2013-10-01

114

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

115

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

Microsoft Academic Search

Current induced composition gradients were demonstrated in the molten LiCl-KCl eutectic mixture, the electrolyte of an LiAl\\/LiCl-KCl\\/FeS\\/sub x\\/ battery. The gradients were produced by electrolysis of the salt between LiAl electrodes at currents of 50 to 100 mA cm⁻², and quenching. Analysis of composition profiles in quenched samples was by atomic absorption spectroscopy, which gave good precision, and by x-ray

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

1981-01-01

116

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

PubMed

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

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

2009-11-15

117

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

PubMed Central

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

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

2011-01-01

118

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

119

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

SciTech Connect

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

Moullet, A. [National Radio Astronomy Observatory, Charlottesville, VA-22902 (United States); Lellouch, E.; Moreno, R. [LESIA-Observatoire de Paris, 5 place J. Janssen, F-92195 Meudon CEDEX (France); Gurwell, M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA-02138 (United States); Black, J. H [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Butler, B. [National Radio Astronomy Observatory, Socorro, NM-87801 (United States)

2013-10-10

120

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

121

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

SciTech Connect

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

Eun, H.C.; Cho, Y.Z.; Choi, J.H.; Kim, J.H.; Lee, T.K.; Park, H.S.; Kim, I.T.; Park, G.I. [Nuclear Fuel Cycle Waste Treatment Research Division, Korea Atomic Energy Research Institute, 989-111 Daedeok-Daero, Yuseong-Gu, Daejeon 3054-353 (Korea, Republic of)

2013-07-01

122

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.

123

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

124

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

125

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

PubMed

This study investigated the influence of partial substitution of NaCl with KCl on the formation of volatile compounds in bacons during processing using a purge and trap dynamic headspace GC/MS system. Three substitutions were 0% KCl (I), 40% KCl (II), and 70% KCl (III). The profiles of the volatile compounds significantly changed during processing, particularly during the drying/ripening. At the end of process, the bacons from substitution III formed significantly higher levels of lipid-derived volatiles, such as straight chain aldehydes, hydrocarbons than bacons from substitution I and II, whereas the latter formed higher levels of volatiles from amino acid degradation such as 3-methylbutanal. There were very few differences in volatile formation between 0% and 40% KCl application. These results suggest that K(+) substitution of Na(+) by more than 40% may significantly change profiles of volatiles in finished dry-cured bacons and therefore would result in changes in the product aroma and/or flavour. PMID:25442569

Wu, Haizhou; Zhuang, Hong; Zhang, Yingyang; Tang, Jing; Yu, Xiang; Long, Men; Wang, Jiamei; Zhang, Jianhao

2015-04-01

126

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

127

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

128

Deafness and renal tubular acidosis in mice lacking the K-Cl co-transporter Kcc4.  

PubMed

Hearing depends on a high K(+) concentration bathing the apical membranes of sensory hair cells. K(+) that has entered hair cells through apical mechanosensitive channels is transported to the stria vascularis for re-secretion into the scala media(). K(+) probably exits outer hair cells by KCNQ4 K(+) channels(), and is then transported by means of a gap junction system connecting supporting Deiters' cells and fibrocytes() back to the stria vascularis. We show here that mice lacking the K(+)/Cl(-) (K-Cl) co-transporter Kcc4 (coded for by Slc12a7) are deaf because their hair cells degenerate rapidly after the beginning of hearing. In the mature organ of Corti, Kcc4 is restricted to supporting cells of outer and inner hair cells. Our data suggest that Kcc4 is important for K(+) recycling() by siphoning K(+) ions after their exit from outer hair cells into supporting Deiters' cells, where K(+) enters the gap junction pathway. Similar to some human genetic syndromes(), deafness in Kcc4-deficient mice is associated with renal tubular acidosis. It probably results from an impairment of Cl(-) recycling across the basolateral membrane of acid-secreting alpha-intercalated cells of the distal nephron. PMID:11976689

Boettger, Thomas; Hübner, Christian A; Maier, Hannes; Rust, Marco B; Beck, Franz X; Jentsch, Thomas J

2002-04-25

129

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

PubMed

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

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

2013-07-01

130

Growth mechanism of thin solid film of long chain compounds on the surface of KCl substrate in molecular level  

NASA Astrophysics Data System (ADS)

The growth mechanism of a long chain compound, calcium stearate, (CH 3(CH 2) 16COO) 2Ca, having the molecular orientation parallel to the surface of the KCl substract is investigated with transmission electron microscopy using the Ge decoration method. After forming thin solid films in vacuo at 25°C, the substrate temperature ( Ts) was raised to 30-60°C for a few minutes. The slender growth hillocks preferentially grow in a configuration, in which the molecules lie on the surface and epitaxially arrange along the <110> axes of the KCl substrate. The growth rate is evaluated determining the increase in length of these growth hillocks as a function of elapsing time treated at different Ts. In addition, the density of growth hillocks per unit area is found to be inversely proportional to Ts. From the dependence of the growth rate and surface diffusion velocity on the annealing temperature, we have obtained the activation energies, 98 and 50 kJ/mol, whose values correspond to the crystal growth of growth hillocks and surface diffusion of molecules, respectively.

Yase, Kiyoshi; Yamanaka, Mikihiro; Sato, Kiyotaka

131

Electrodeposition of Mg-Li-Al-La Alloys on Inert Cathode in Molten LiCl-KCl Eutectic Salt  

NASA Astrophysics Data System (ADS)

Electrochemical preparation of Mg-Li-Al-La alloys on inert electrodes was investigated in LiCl-KCl melt at 853 K (580 °C). Cyclic voltammograms (CVs) and square wave voltammograms (SWVs) show that the existence of AlCl3 or AlF3 could promote La deposition on an active Al substrate, which is predeposited on inert electrodes. All electrochemical tests show that the reduction of La3+ is a one-step reduction process with three electrons exchanged. The reduction of La(III)?La(0) occurred at -2.04 V, and the underpotential deposition (UPD) of La was detected at -1.55 V ( vs Ag/AgCl). The same phenomena concerning La UPD were observed on two inert cathodes, W and Mo. In addition, Mg-Li-Al-La alloys were obtained by galvanostatic electrolysis on the W cathode from La2O3 in LiCl-KCl-MgCl2-KF melts with aluminum as the anode. X-ray diffraction (XRD) measurements indicated that various phases like the Al2La, Al12Mg17, and ?Li phase (LiMg/Li3Mg7) existed in the Mg-Li-Al-La alloys. The distribution of Mg, Al, and La in Mg-Li-Al-La alloys from the analysis of a scan electron micrograph (SEM) and energy dispersive spectrometry (EDS) indicated that the elements Mg, Al, and La distributed homogeneously in the alloys.

Han, Wei; Chen, Qiong; Sun, Yi; Jiang, Tao; Zhang, Milin

2011-12-01

132

In situ STM studies of electrochemically polished Cd(0001) electrode in aqueous electrolyte solutions  

NASA Astrophysics Data System (ADS)

The in situ STM studies of electrochemically polished Cd(0001) electrode in the H3PO4 aqueous solution have been performed under negative electrode potentials from - 1.4 to - 0.9 V (versus Ag|AgCl in sat. KCl aqueous solution) in the 0.1 M Na2SO4 + 1 × 10- 5 M H2SO4 aqueous solution. The atomic resolution parameters of Cd(0001) surface have been calculated. The in situ STM data show that there are no surface reconstruction processes and the surface structure of electrochemically polished Cd(0001) is stable within the potential region investigated.

Pikma, P.; Grozovski, V.; Kasuk, H.; Lust, E.

2014-10-01

133

Eu-doped KCl phosphor crystals as a storage material for two-dimensional ultraviolet-ray or x-ray imaging sensors  

NASA Astrophysics Data System (ADS)

Intense optically stimulated luminescence (OSL) with a peak at about 430 nm is observed in ultraviolet (UV)-ray or x-ray irradiated europium-doped potassium chloride (KCl:Eu) phosphor crystals. The OSL intensity is increased with increasing UV-ray or x-ray irradiation dose. This suggests that KCl:Eu phosphor crystal is useful as a material for two-dimensional UV-ray or x-ray imaging sensor utilizing OSL phenomenon. The results obtained are consistent with the proposed emission mechanisms of the 420 nm OSL peak, based on the recombination of electrons released from the F centers with Eu3+ ions. The excitation mechanism for the OSL in UV-ray irradiated KCl:Eu phosphor crystals is also discussed.

Nanto, H.; Endo, F.; Hirai, Y.; Nasu, S.; Taniguchi, S.; Takeuchi, N.

1994-06-01

134

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

SciTech Connect

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

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, 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, 30-059 Krakow (Poland)

2009-09-25

135

Preparation of Mo nanopowders through electroreduction of solid MoS2 in molten KCl-NaCl.  

PubMed

Electrolysis of MoS2 to produce Mo nanopowders and elemental sulfur has been studied in an equimolar mixture of NaCl and KCl at 700 °C. The reduction mechanism was investigated by cyclic voltammetry (CV), potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction pathway was identified to be MoS2 ? LxMoS2 (x ? 1, L = Na or K) ? L3Mo6S8 and LMo3S3 ? Mo, and the last step to format metallic Mo was found to be relatively slow in kinetics. Electrolysis at a cell voltage of 2.7 V has led to a rapid reduction of MoS2 to nodular Mo nanoparticles (50-100 nm), with the current efficiency and energy consumption being about 92% and 2.07 kW h kg(-1)-Mo, respectively. PMID:25105181

Gao, Haiping; Tan, Mingsheng; Rong, Liangbin; Wang, Zhiyong; Peng, Junjun; Jin, Xianbo; Chen, George Z

2014-09-28

136

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

PubMed

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

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

2014-01-01

137

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

NASA Astrophysics Data System (ADS)

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

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

2005-09-01

138

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

139

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

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

140

Influence of the mineralogical composition on the self-potential response to1 advection of KCl concentration fronts through sand.2  

E-print Network

concentration fronts through sand.2 3 Alexis Maineult, Laurence Jouniaux and Yves Bernabé4 5 Institut de of KCl12 concentration fronts through two laboratory-scale sand-bodies with different13 mineralogical composition. In pure quartz sand, the amplitude and polarity of the SP14 signals agreed with a previously

Paris-Sud XI, Université de

141

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

142

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

PubMed Central

Purpose: The activator ion (Eu2+ in KCl:Eu2+) plays an important role in the photostimulated luminescence (PSL) mechanism of storage phosphor radiation detectors. In order to design an accurate, effective, and robust detector, it is important to understand how the activator ion concentration affects the structure and, consequently, radiation detection properties of KCl:Eu2+. Methods: Potassium chloride pellets were fabricated with various amounts of europium dopant (0.01–5.0 mol.% Eu2+). Clinical radiation doses were given with a 6 MV linear accelerator. Radiation doses larger than 100 Gy were given with a 137Cs irradiator. Dose response curves, radiation hardness, and temporal signal stability were measured using a laboratory PSL readout system. The crystal structure of the material was studied using x ray diffraction and luminescence spectroscopy. Results: The most intense PSL signal was from samples with 1.0 mol.% Eu. However, samples with concentrations higher than 0.05 mol.% Eu exhibited significant degradation in PSL intensity for cumulated doses larger than 3000 Gy. Structural and luminescence spectroscopy showed clear evidence of precipitate phases within the KCl lattice, especially for high activator concentrations. Analysis of PL emission spectra showed that interactions between Eu-Vc dipoles and Eu-Vc trimers could explain trends in PSL sensitivity and radiation hardness observations. Conclusions: The concentration of the activator ion (Eu2+) significantly affects radiation detection properties of the storage phosphor KCl:Eu2+. An activator concentration between 0.01 and 0.05 mol.% Eu in KCl:Eu2+ storage phosphor detectors is recommended for linear dose response, good PSL sensitivity, predictable temporal stability, and high reusability for megavoltage radiation detection. PMID:24007173

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

2013-01-01

143

Conservative management of cervical pregnancy with intramuscular administration of methotrexate and KCl injection: Case report and review of the literature.  

PubMed

We report the case of a cervical pregnancy successfully treated with intramuscular injection of methotrexate (MTX) and intramniotic administration of potassium chloride. A 41-year-old woman was admitted to our Department with the suspicion of ectopic pregnancy. Transvaginal ultrasound revealed empty endometrial cavity, gestational sac within the cervical canal and embryonic echo measuring crown rump length 1.5 mm. Serum beta human chorionic gonadotropine (?-HCG) was measured 28590 IU/L. No cardiac activity was detected. The diagnosis of a cervical pregnancy was made. Patient was treated with intramuscular administration of methotrexate (50 mg/m(2)) in combination with ultrasound-guided intramniotic injection of KCl (2 meq/mL). Gradual decrease of ?-HCG levels as well as ultrasound observation of collapsed gestational sac was observed. No curettage was necessitated. Patient was discharged on day 10(th) and was set in follow-up on a weekly basis. ?-HCG values were measured < 10 IU/L on 56(th) day after MTX administration. Intramuscular administration of MTX may be effective in treatment of cervical pregnancy without additional interventional measures. PMID:25610854

Petousis, Stamatios; Margioula-Siarkou, Chrysoula; Kalogiannidis, Ioannis; Karavas, George; Palapelas, Vasileios; Prapas, Nikolaos; Rousso, David

2015-01-16

144

MeV-ion axial surface-channeling from an electron irradiated KCl(0 0 1) surface  

NASA Astrophysics Data System (ADS)

Surface-channeling of protons incident with 5 mrad on an electron-irradiated surface is investigated using a 0.55 MeV beam of protons. The target surface is KCl(0 0 1), which is damaged by electron-stimulated desorption with 5 keV electron irradiation. The direction of the incident beam is adjusted along the <1 0 0> and <1 1 0> channeling conditions and the channeling-dips of the scattering yields are observed. The irradiation dose-dependence of the minimum yields and widths of the dips is measured. Two dips are compared, i.e., for the <1 0 0> and <1 1 0> channelings. By increasing the irradiation dose up to 2 × 10 16 cm -2, the dip around the <1 0 0> axis becomes opened, but that of the <1 1 0> axis becomes shallow. The irradiated surfaces are observed to have many overlapped terraces of sub-micron with monolayer steps. The surface morphology deformed by the irradiation effects to truncate trajectories of the <1 0 0> channeling protons. This roughness of the surface is more effective for the trajectories of the <1 1 0> channeling protons. The protons incident on the rough surface along the <1 1 0> axis are not reflected from the atomic row but reflected by a potential of the surface with steps. Results by a simple computer simulation of the trajectories of protons at stepped surfaces also indicate the scattering processes.

Fukazawa, Yuuko; Matsumoto, Yuugo; Mitsuhara, Kei; Susuki, Yasufumi

2009-11-01

145

{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

146

Lambda-p femtoscopy in collisions of Ar+KCl at 1.76 AGeV  

E-print Network

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 small 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 slightly smaller than the pp correlation radius for a similar collis ion system. The present $\\Lambda$p radius is significantly smaller than that found for Au+Au/Pb+Pb collisio ns 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.

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

2010-04-14

147

Conservative management of cervical pregnancy with intramuscular administration of methotrexate and KCl injection: Case report and review of the literature  

PubMed Central

We report the case of a cervical pregnancy successfully treated with intramuscular injection of methotrexate (MTX) and intramniotic administration of potassium chloride. A 41-year-old woman was admitted to our Department with the suspicion of ectopic pregnancy. Transvaginal ultrasound revealed empty endometrial cavity, gestational sac within the cervical canal and embryonic echo measuring crown rump length 1.5 mm. Serum beta human chorionic gonadotropine (?-HCG) was measured 28590 IU/L. No cardiac activity was detected. The diagnosis of a cervical pregnancy was made. Patient was treated with intramuscular administration of methotrexate (50 mg/m2) in combination with ultrasound-guided intramniotic injection of KCl (2 meq/mL). Gradual decrease of ?-HCG levels as well as ultrasound observation of collapsed gestational sac was observed. No curettage was necessitated. Patient was discharged on day 10th and was set in follow-up on a weekly basis. ?-HCG values were measured < 10 IU/L on 56th day after MTX administration. Intramuscular administration of MTX may be effective in treatment of cervical pregnancy without additional interventional measures. PMID:25610854

Petousis, Stamatios; Margioula-Siarkou, Chrysoula; Kalogiannidis, Ioannis; Karavas, George; Palapelas, Vasileios; Prapas, Nikolaos; Rousso, David

2015-01-01

148

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

149

The single-electrode Peltier heats of Li-Al alloy electrodes in LiCl-KCl eutectic system  

SciTech Connect

This paper presents the single-electrode Peltier heat of cathodic (or anodic) reaction of Li-Al alloy electrode in a coexisting phase state, or an intermetallic compound phase state estimated by thermoelectric-power measurement. The thermoelectric-power measurements of Li-Al alloys in various coexisting phase states were carried out with both potentiometric and potential-sweep methods in the LiCl-KCl eutectic system between 673 and 843 K. The values of the thermoelectric power of Li-Al alloys calculated by using thermodynamic literature data were in good agreement with those obtained by experiment. The single-electrode Peltier heat changes drastically with change of its phase state, and it was found that the formation reactions of [beta] (Li[sub 0.5]Al[sub 0.5]) and [gamma] (Li[sub 0.6]Al[sub 0.4]) phases are exothermic, and those of liquid phase from [beta] and [gamma] phase are endothermic. The single-electrode Peltier heat for the cathodic formation reaction of Li-Al alloy in intermetallic compound [gamma] phase is estimated to be exothermic by using the measured values of thermoelectric powers of Li-Al alloys in ([beta] + [gamma]) and ([gamma] + liq.) regions.

Amezawa, Koji; Ito, Yasuhiko; Tomii, Yoichi (Kyoto Univ. (Japan))

1994-11-01

150

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

151

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

SciTech Connect

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

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

1982-10-01

152

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

PubMed

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

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

2014-06-01

153

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

Microsoft Academic Search

Current-induced composition gradients have been predicted in mixed molten salt battery electrolytes. Composition shifts, if large enough, can produce significant deleterious effects, such as solid phase precipitation in or near the electrodes of molten salt batteries, including the LiAl\\/LiCl-KCl\\/FeS\\/sub x\\/ battery. Quantitative measurements are needed to determine the extent of the gradients and to find means to reduce them. This

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

1982-01-01

154

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

SciTech Connect

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

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

2011-03-01

155

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

PubMed

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

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

2008-12-30

156

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

PubMed

The calcium hydroxyapatite Ca(10)(PO(4))(6)(OH)(2) (Hap) nanoparticles were prepared by using microreactor and employed these Hap nanoparticles to clarify the adsorption behavior of proteins. The size of Hap particles produced by the microreactor reduced in the order of a hardness of the reaction conditions for mixing Ca(OH)(2) and H(3)PO(4) aqueous solutions, such as flow rates of both solutions and temperature. Finally, the size of the smallest Hap nanoparticle became 2 × 15 nm(2), similar to that of BSA molecule (4 × 14 nm(2)). It is noteworthy that the smallest Hap nanoparticles still possesses rodlike shape, suggesting that particles are grown along c-axis even though the reactants mixed very rapidly in narrow channels of the microreactors. The X-ray diffraction patterns of the Hap nanoparticles revealed that the crystallinity of the materials produced by the microreactor is low. The FTIR measurement indicated that the Hap nanoparticles produced by microreactor were carbonate-substituted type B Hap, where the carbonate ions replace the phosphate ions in the crystal lattice. All the adsorption isotherms of acidic bovine serum albumin (BSA), neutral myoglobin (MGB), and basic lysozyme (LSZ) onto Hap nanoparticles from 1 × 10(-4) mol/dm(3) KCl solution were the Langmuirian type. The saturated amounts of adsorbed BSA (n(S)(BSA)) for the Hap nanoparticles produced by microreactor were decreased with decrease in the mean particle length, and finally it reduced to zero for the smallest Hap nanoparticles. Similar results were observed for the adsorption of LSZ; the saturated amounts of adsorbed LSZ (n(S)(LSZ)) also reduced to zero for the smallest Hap nanoparticles. However, in the case of MGB, the saturated mounts of adsorbed MGB (n(S)(MGB)) are also depressed with decreased in their particle size, but about half of MGB molecules still adsorbed onto the smallest Hap nanoparticles. This difference in the protein adsorption behavior was explained by the difference in the size and flexibility of three kinds of proteins. The reduction of n(S)(BSA) is due to the decrease in the fraction of C sites on the side face of each Hap nanoparticle; i.e., there is not enough area left on the nanoparticle surface to adsorb large BSA molecules even though the BSA molecules are soft and their conformations are alterable. The reduction of n(S)(LSZ) was explained by the reduction of P sites. Further, rigidity of the LSZ molecules was given another possibility of the depression of n(S)(LSZ) for the Hap nanoparticles. However, MGB molecules with small and soft structure were adsorbed on the Hap nanoparticle surface by changing their conformation. We could control the amounts of adsorbed proteins by changing the particle size of Hap in the nanometer range and kinds of proteins. These obtained results may be useful for developing biomimetic materials for bone grafts and successful surgical devices in the biochemical field. PMID:21162543

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

2011-02-01

157

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

Microsoft Academic Search

Composition gradients such as those predicted to occur during discharge of porous Li-Al negative electrodes of Li\\/S batteries with LiCl-KCl eutectic electrolyte were generated and measured in the LiCl-KCl anolyte of an electrolysis cell with Li-Al electrodes. LiCl precipitation during electrolysis was observed by two-dimensional scanning of electrolyte composition in the front part of quenched porous Li-Al anode sections using

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

1983-01-01

158

Electrochemical formation of Dy alloy films in a molten LiCl-KCl-DyCl3 system  

NASA Astrophysics Data System (ADS)

As to the electrochemical formation of Dy-Ni alloy films in a molten LiCl-KCl-DyCl3 system at 700 K, the growth of DyNi2 film and behavior of anodic dissolution of Dy from the formed DyNi2 film were investigated. The DyNi2 films were formed by potentiostatic electrolysis at 0.55, 0.62 and 0.70 V with Ni electrodes. The growth rates of DyNi2 films are higher at less noble potential, i.e., 0.47 8m min-1 at 0.55 V, 0.32 8m min-1 at 0.62 V and 0.14 8m min-1 at 0.70 V. From RBS analysis, it was suggested that the Dy-Ni alloy film was formed for 10 or 30 s during electrodepositing Dy at 0.30 V with a Ni electrode. Moreover, the growth rate of Dy-Ni alloy film was faster than that of Dy-Fe alloy film. Anodic electrolysis of the formed DyNi2 film with thickness of 15 ?m was conducted at 0.90 V, 1.30 V and 1.90 V, respectively. The formed DyNi2 were transformed to other phases, i.e., DyNi3, DyNi5 and Ni, by selective anodic dissolution of Dy. The transformed Ni film was about 10 ?m in thickness and had a porous structure with a pore diameter of 1~2 ?m.

Konishi, H.; Usui, T.; Nohira, T.; Ito, Y.

2009-05-01

159

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

160

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

161

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

NASA Astrophysics Data System (ADS)

Previous studies performing dual isotopic analysis of nitrate in KCl soil extracts using denitrifying bacteria have not incorporated alterations in the method to compensate for the increased N2O blank produced when the bacteria are exposed to KCl in solution. When 1M KCl is used as a blank, the amount of N2O released from the concentrated bacteria solution is more than four times as high as when using a DI water blank. The excess N2O produced is not an artifact of nitrate impurity in the KCl, although the blank increases with the molarity of KCl up to 1M. The introduction of N2O gas is significant enough to alter the values of IAEA USGS standards (3 ?g in 3ml KCl) which in turn results in an inaccurate regression for unknown samples. We reduced the size of the KCl blank and its effect on the standards by adding 3ml of KCl to the bacteria solution prior to purging the sample with He gas. This removes the N2O gas which is released by the bacteria when they initially come in contact with the KCl, and allows for standards to be calibrated to a precision of ± 0.1 % ?15N and ± 0.2 % ?18O. Using this new method, we measured ?15N and ?18O of nitrate in 1M KCl soil extracts taken from surface soil (5cm cores) along a nitrogen deposition gradient spanning the Coachella Valley in the western Sonoran Desert during the summer. Early germinating winter annual plant species (Schismus barbatus, Chaenactic fremontii, and Malacothrix glabrata) were collected as seedlings early in the growing season and again in late spring before senescence. Leaves from the dominant shrub, Larrea tridentata, were also collected from each site. Soil nitrogen from sites on the eastern edge of the valley had ?18O values between +30 and +41%, indicating an influence of atmospheric nitrate in plant available nitrate. There was an inverse correlation (r2=0.907) between soil ?18O and the ?15N of the C.fremontii leaf tissue, which suggests that in areas of high N deposition, some seedlings are able to take up excess nitrogen deposited to the soil surface in the summer. Leaf tissue from L. tridentata had a similar relationship with calculated summer atmospheric nitrogen deposition. These results indicate anthropogenic nitrate is only evident in the soils in areas of high deposition and that isotopic composition of the leaf tissue of some widespread species may be able to be used as a bioindicator of deposition.

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

2011-12-01

162

Two developmental switches in GABAergic signalling: the K+-Cl- cotransporter KCC2 and carbonic anhydrase CAVII.  

PubMed

GABAergic signalling has the unique property of 'ionic plasticity', which is based on short-term and long-term changes in the Cl(-) and HCO(3)(-) ion concentrations in the postsynaptic neurones. While short-term ionic plasticity is caused by activity-dependent, channel-mediated anion shifts, long-term ionic plasticity depends on changes in the expression patterns and kinetic regulation of molecules involved in anion homeostasis. During development the efficacy and also the qualitative nature (depolarization/excitation versus hyperpolarization/inhibition) of GABAergic transmission is influenced by the neuronal expression of two key molecules: the chloride-extruding K(+)-Cl(-) cotransporter KCC2, and the cytosolic carbonic anhydrase (CA) isoform CAVII. In rat hippocampal pyramidal neurones, a steep up-regulation of KCC2 accounts for the 'developmental switch', which converts depolarizing and excitatory GABA responses of immature neurones to classical hyperpolarizing inhibition by the end of the second postnatal week. The immature hippocampus generates large-scale network activity, which is abolished in parallel by the up-regulation of KCC2 and the consequent increase in the efficacy of neuronal Cl(-) extrusion. At around postnatal day 12 (P12), an abrupt, steep increase in intrapyramidal CAVII expression takes place, promoting excitatory responses evoked by intense GABAergic activity. This is largely caused by a GABAergic potassium transient resulting in spatially widespread neuronal depolarization and synchronous spike discharges. These facts point to CAVII as a putative target of CA inhibitors that are used as antiepileptic drugs. KCC2 expression in adult rat neurones is down-regulated following epileptiform activity and/or neuronal damage by BDNF/TrkB signalling. The lifetime of membrane-associated KCC2 is very short, in the range of tens of minutes, which makes KCC2 ideally suited for mediating GABAergic ionic plasticity. In addition, factors influencing the trafficking and kinetic modulation of KCC2 as well as activation/deactivation of CAVII are obvious candidates in the ionic modulation of GABAergic responses. The down-regulation of KCC2 under pathophysiological conditions (epilepsy, damage) in mature neurones seems to reflect a 'recapitulation' of early developmental mechanisms, which may be a prerequisite for the re-establishment of connectivity in damaged brain tissue. PMID:15528236

Rivera, Claudio; Voipio, Juha; Kaila, Kai

2005-01-01

163

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

PubMed Central

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

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

2014-01-01

164

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

E-print Network

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

Park, Byungwoo

165

Vibrational spectroscopy at high pressures—LVI. A Raman study of some alkali metal halates, and the X-ray compressibility of KClO 3  

NASA Astrophysics Data System (ADS)

Raman spectra at high pressure have been obtained for KBrO 3, NaClO 3 and NaBrO 3 in a diamond anvil cell. A phase change has been found for KBrO 3 at 19 kbar; at 24 kbar for NaBrO 3; and at 36 kbar for NaClO 3. The bulk compressibility of KClO 3 has been determined by X-ray diffraction using synchrotron radiation and found to be 2.36 × 10 -2 GPa -1, in good agreement with Bridgman's value.

Adams, David M.; Heath, Andrew E.; Pogson, Mark; Ruff, Philip W.

166

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

PubMed Central

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

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

2015-01-01

167

Electrochemical study of the codeposition of Mg–Li–Al alloys from LiCl–KCl–MgCl 2 –AlCl 3 melts  

Microsoft Academic Search

This work presents a novel electrochemical study on the codeposition of Mg, Li and Al on a molybdenum electrode in LiCl–KCl–MgCl2–AlCl3 melts at 943 K to form Mg–Li–Al alloys. Cyclic voltammograms (CVs) showed that the underpotential deposition (UPD) of magnesium\\u000a on pre-deposited aluminum leads to the formation of a liquid Mg–Al solution, and the succeeding underpotential deposition\\u000a of lithium on pre-deposited

Yong De Yan; Mi Lin Zhang; Yun Xue; Wei Han; Dian Xue Cao; Li Yi He

2009-01-01

168

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

169

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

170

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

SciTech Connect

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

K. C. Marsden; B. Pesic

2011-04-01

171

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

172

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

SciTech Connect

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

N. A. Anderson; P. Sabharwall

2012-06-01

173

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

E-print Network

The most common rechargeable battery, the lead-acid battery,rechargeable batteries, thus creating the "electric" car. These battery-battery for electric vehicles, though, has proven difficult. The rechargeable

Jain, R.

2010-01-01

174

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

175

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

176

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

177

Electroanalytical study of the reduction of K[sub 2]WCl[sub 6] in molten LiCl-KCl eutectic  

SciTech Connect

The mechanisms of the reduction of K[sub 2]WCl[sub 6] in molten LiCl-KCl eutectic was studied using cyclic voltammetry, chronopotentiometry, and controlled potential coulometry over a temperature range of 400 to 500 C and a WCl[sup 2-][sub 6] concentration of 0.0005 to 0.005 mol/liter. A single irreversible wave attributed to the reduction of W(IV) to W(III) was observed. The experimental results further indicated the process to be diffusion controlled with n[approximately]1.3 and [alpha] ranging from 0.85 to 0.95. W(III) is soluble at 500 C and insoluble, but still electroactive, below 460 C.

Sequeira, C.A.C. (Technical Univ. of Lisbon, Lisboa (Portugal). Inst. Superior Tecnico)

1993-09-01

178

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

PubMed

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

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

2005-04-01

179

The Resveratrol-induced Relaxation of Cholecystokinin Octapeptide- or KCl-induced Tension in Male Guinea Pig Gallbladder Strips Is Mediated Through L-type Ca2+ Channels  

PubMed Central

Background/Aims Resveratrol (3,5,4?-trihydroxystilbene) is a polyphenolic compound (stilbene) and a phytoalexin. The purpose of this study was to determine the mechanism which mediated the resveratrol-induced relaxation of cholecystokinin octapeptide- or KCl-induced tension in male guinea pig gallbladder strips. Methods Gallbladder strips were prepared and suspended in in vitro chambers filled with Krebs-Henseleit solution. The strips were attached to force displacement transducers, and the changes in tension were recorded on a polygraph. All reagents were added directly into the chambers. Results To determine if intracellular Ca2+ release mediated the resveratrol-induced relaxation of cholecystokinin octapeptide-induced tension, 2-aminoethoxydiphenylborane (2-APB) was used. 2-APB significantly (P < 0.01) decreased the amount of RSVL-induced relaxation. To determine if protein kinase A (PKA) mediated the resveratrol-induced relaxation, PKA inhibitor 14-22 amide myristolated (PKA-IM) was used. PKA-IM had no effect on resveratrol-induced relaxation. Neither KT5823, NG-methyl-L-arginine acetate salt, a nitric oxide synthase inhibitor, nor fulvestrant had a significant effect on the amount of resveratrol-induced relaxation. Genistein, a protein tyrosine kinase inhibitor, significantly (P < 0.01) increased the RSVL-induced relaxation. To determine if protein kinase C mediated the RSVL-induced relaxation, the protein kinase C inhibitors bisindolymaleimide IV and chelerythrine Cl- were used together, and a significant (P < 0.05) increase in resveratrol-induced relaxation was observed. The pretreatment of the strips with resveratrol significantly (P < 0.001) decreased the amount of KCl- and cholecystokinin octapep-tide-induced tension. Conclusions Resveratrol-induced relaxation is mediated by its effects on L-type Ca2+ channels and intracellular Ca2+ release. PMID:25537678

Kline, Loren W; Karpinski, Edward

2015-01-01

180

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

PubMed

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

Cañas, A; Benavente, J

2002-02-15

181

First-principles super-cell investigation of the rattling effect in Li-doped KCl This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

First-principles super-cell investigation of the rattling effect in Li-doped KCl This article has. Phys.: Condens. Matter 21 (2009) 045401 (5pp) doi:10.1088/0953-8984/21/4/045401 First-principles super-cell the results of super-cell calculations of the energy associated with displacing the Li along 100 , 110 and 111

Daw, Murray S.

182

Development of monetite-nanosilica bone cement: a preliminary study.  

PubMed

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

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

2014-11-01

183

Electrochemical-Impedance-Spectroscopy Study of Corrosion of the Alloy NF616 with Molten ZnCl2-KCl Coating in Air at 673 K  

NASA Astrophysics Data System (ADS)

The corrosion behavior of the alloy NF616 covered with a film of molten 0.55ZnCl2-0.45KCl (mole fraction), similar to that found in waste incineration plants, was examined in air at 673 K by the electrochemical-impedance spectroscopy (EIS) technique. For comparison, the corrosion of the same material immersed in the deep salt was also studied. The electrochemical impedance spectra for the corrosion of NF616 beneath a film of fused salt consisted of a semi-circle at high-frequency port and a line at low-frequency port indicating a diffusion-controlled reaction. Contrary to the corrosion beneath salt film, the corrosion of the alloy in deep molten salt presented the characteristics of two capacitive loops during all the duration of the experimental test. This different EIS features under two corrosion conditions may be related to the different supply of oxygen amount. In this paper, suitable equivalent circuits representing the corrosion of the alloy under the two different corrosion conditions are proposed to fit the corresponding impedance spectra and electrochemical parameters in the equivalent circuits are also calculated.

Pan, T. J.; Xue, W. L.; Chen, D. G.; Hu, J.

2011-04-01

184

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

SciTech Connect

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

Dai, S.; Toth, L.M.; Del Cul, G.D.; Metcalf, D.H. [Oak Ridge National Lab., TN (United States)

1995-01-04

185

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

186

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

NSDL National Science Digital Library

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

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

2006-10-01

187

Taurine Inhibits K+-Cl? Cotransporter KCC2 to Regulate Embryonic Cl? Homeostasis via With-no-lysine (WNK) Protein Kinase Signaling Pathway*  

PubMed Central

GABA inhibits mature neurons and conversely excites immature neurons due to lower K+-Cl? cotransporter 2 (KCC2) expression. We observed that ectopically expressed KCC2 in embryonic cerebral cortices was not active; however, KCC2 functioned in newborns. In vitro studies revealed that taurine increased KCC2 inactivation in a phosphorylation-dependent manner. When Thr-906 and Thr-1007 residues in KCC2 were substituted with Ala (KCC2T906A/T1007A), KCC2 activity was facilitated, and the inhibitory effect of taurine was not observed. Exogenous taurine activated the with-no-lysine protein kinase 1 (WNK1) and downstream STE20/SPS1-related proline/alanine-rich kinase (SPAK)/oxidative stress response 1 (OSR1), and overexpression of active WNK1 resulted in KCC2 inhibition in the absence of taurine. Phosphorylation of SPAK was consistently higher in embryonic brains compared with that of neonatal brains and down-regulated by a taurine transporter inhibitor in vivo. Furthermore, cerebral radial migration was perturbed by a taurine-insensitive form of KCC2, KCC2T906A/T1007A, which may be regulated by WNK-SPAK/OSR1 signaling. Thus, taurine and WNK-SPAK/OSR1 signaling may contribute to embryonic neuronal Cl? homeostasis, which is required for normal brain development. PMID:22544747

Inoue, Koichi; Furukawa, Tomonori; Kumada, Tatsuro; Yamada, Junko; Wang, Tianying; Inoue, Rieko; Fukuda, Atsuo

2012-01-01

188

An AFM study of the thermal development of the (0 0 1) surface of KCl from room temperature up to the melting point  

NASA Astrophysics Data System (ADS)

The topographical development of the (0 0 1) surface of KCl was investigated from room temperature up to the melting point by atomic force microscopy in UHV. Cleavage topographies of air-cleaved surfaces show extended growth hills formed by large numbers of rounded, mostly monatomic steps caused by the re-crystallization of crystal material dissolved in adsorbed water layers. Vacuum cleaved surfaces are more irregular. They exhibit among others sharp cleavage tips, which seem to be characteristic for ionic crystals. At moderately heated surfaces, 673 K, closed loop lamella systems as well as different types of spiral systems originating from edge and screw dislocations, respectively, are observed. High resolution images of spiral centers exhibit the emergence of mono and diatomic steps from the surface. The centers of closed loop step systems could not be visualized. After stronger heating, at 773 and 873 K, extended evaporation pits with macro-steps of heights between 20 and 35 nm are found. After shortly exceeding the melting point at about 1013 K, the surface is covered by macro-steps of heights between 3 and 5 nm and mono and diatomic steps running diagonally across the terraces between the high steps.

Ostadrahimi, A. H.; Dabringhaus, H.; Wandelt, K.

2002-12-01

189

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

190

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

191

Characterization of phosphoric acid doped TGS single crystals  

Microsoft Academic Search

Single crystals of phosphoric acid (H3PO4) doped triglycine sulfate (TGSP) are grown from aqueous solution containing 10–50mol% of H3PO4. Large sized crystals of dimension (70mm×40mm×25mm) suitable for IR detector applications are obtained with 20mol% of H3PO4. They exhibit elongated domains, and the domain density is higher than in undoped TGS crystals. FT-IR analysis indicates the presence of both zwitter and

Aparna Saxena; Vinay Gupta; K. Sreenivas

2004-01-01

192

Pyroelectric properties of phosphoric acid-doped TGS single crystals  

Microsoft Academic Search

Pyroelectric properties of phosphoric acid (H3PO4)-doped triglycine sulfate (TGSP) single crystals grown from solutions containing 0.1-0.5 mol of H3PO4 have been studied. Incorporation of H3PO4 into the crystal lattice is found to induce an internal bias field (Eb) and is observed through the presence of a sustained polarization and pyroelectricity beyond the transition temperature. The internal bias field has been

Aparna Saxena; M. Fahim; Vinay Gupta; K. Sreenivas

2003-01-01

193

Quantifying local and cooperative components in the ferroelectric distortion of BaTiO(3): learning from the off-center motion in the MnCl(6)(5-) complex formed in KCl:Mn(+).  

PubMed

The delicate balance between cooperative and local contributions in the ferroelectric distortions of BaTiO3 is explored by means of ab initio calculations. As a salient feature, it is found that a single Ti(4+) ion in BaTiO3 is not allowed to move off-center at ambient pressure, while this is no longer true if the lattice is expanded by only ?5%, stressing the high sensitivity of the local contribution to chemical and hydrostatic pressures. In order to further understand the effect of local contributions on the phase transition mechanism of ferroelectrics, we have investigated the surprising C3v ? C4v ? Oh local transformations occurring in the 10-50 K temperature range for the MnCl6(5-) complex formed in KCl:Mn(+) that mimic the behavior of BaTiO3. From Boltzmann analysis of the vibronic levels derived from ab initio calculations and considering decoherence introduced by random strains, the present calculations reproduce the experimental phase sequence and transition temperatures. Furthermore, our calculations show that the off-center instability in KCl:Mn(+) would be suppressed by reducing by only 1% the lattice parameter, a situation that then becomes comparable to that found for BaTiO3 at ambient pressure. The present results thus stress the deep link between the structural phase transitions of ferroelectric materials and local phase transitions displayed by transition-metal impurities in insulators. PMID:24943232

García-Lastra, J M; García-Fernández, P; Calle-Vallejo, F; Trueba, A; Aramburu, J A; Moreno, M

2014-07-01

194

internal solution containing 140 mM KCl, 2 mM MgCl2, 10 mM EGTA, 10 mM HEPES at pH 7.2. The external solution was Leibovitz's L-15 (Gibco) containing 136 mM NaCl,  

E-print Network

internal solution containing 140 mM KCl, 2 mM MgCl2, 10 mM EGTA, 10 mM HEPES at pH 7.2. The external solution was Leibovitz's L-15 (Gibco) containing 136 mM NaCl, 5.8 mM NaH2PO4, 5.4 mM KCl, 1.3 mM CaCl2, 0.9 mM MgCl2 at pH 7.2. Osmolarity was adjusted to 300 mosM l21 . Motility was measured

Shilo, Benny

195

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

196

LIDAR nleasurenlents of \\vind turbine wake Ineanderi ng J)l'j',lillllL'nl ul \\kcl1~lI1i('al Engineering. Fluid \\kchanic~. \\ills Koppcls /l.ik. DTU-I)uildll1,lC ..jil3.ll'llJ:1il':i1  

E-print Network

rclationshil) bet ween the down stream wake meandering and thc large scale part of thc turbulent innow field~lsi-steady wake characteristics both in terms of wake deficit and wake generated turbulence. As part of the EULIDAR nleasurenlents of \\vind turbine wake Ineanderi ng J)l'j',lillllL'nl ul \\kcl1~lI1i

197

Postnatal development of Na(+)-K(+)-2Cl(-) co-transporter 1 and K(+)-Cl(-) co-transporter 2 immunoreactivity in multiple brain stem respiratory nuclei of the rat.  

PubMed

Previously, we reported that in rats, GABA(A) and glycine receptor immunoreactivity increased markedly in multiple brain stem respiratory nuclei around postnatal days (P) 12-13, a critical period when abrupt neurochemical, metabolic, ventilatory, and electrophysiological changes occur in the respiratory network and when the system is under greater inhibition than excitation. Since Na(+)-K(+)-2Cl(-) co-transporter 1 (NKCC1) and K(+)-Cl(-) co-transporter 2 (KCC2) play pivotal roles in determining the responses of GABA(A) and glycine receptors, we hypothesized that NKCC1 and KCC2 undergo significant changes during the critical period. An in-depth immunohistochemical and single neuron optical densitometric study of neurons in seven respiratory-related nuclei (the pre-Bötzinger complex [PBC], nucleus ambiguus [Amb], hypoglossal nucleus [XII], ventrolateral subnucleus of solitary tract nucleus [NTS(VL)], retrotrapezoid nucleus/parafacial respiratory group [retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG)], dorsal motor nucleus of the vagus nerve [dorsal motor nucleus of the vagus nerve (DMNX)], and inferior olivary nucleus [IO]) and a non-respiratory cuneate nucleus (CN, an internal control) was undertaken in P0-P21 rats. Our data revealed that (1) NKCC1 immunoreactivity exhibited a developmental decrease from P0 to P21 in all eight nuclei examined, being relatively high during the first 1½ postnatal weeks and decreased thereafter. The decrease was abrupt and statistically significant at P12 in the PBC, Amb, and XII; (2) KCC2 immunoreactivity in these eight nuclei showed a developmental increase from P0 to P21; and (3) the significant reduction in NKCC1 and the greater dominance of KCC2 around P12 in multiple respiratory nuclei of the brain stem may form the basis of an enhanced inhibition in the respiratory network during the critical period before the system stabilizes to a more mature state. PMID:22441038

Liu, Q; Wong-Riley, M T T

2012-05-17

198

Phosphate-induced metal immobilization in a contaminated site  

Microsoft Academic Search

To assess the efficiency of P-induced metal immobilization in soils, a pilot-scale field experiment was conducted at a metal contaminated site located in central Florida. Phosphate was applied at a P\\/Pb molar ratio of 4.0 with three treatments: 100% of P from H3PO4, 50% of P from H3PO4+ 50% of P from Ca(H2PO4)2, and 50% of P from H3PO4+5% phosphate

Rocky X. Cao; Lena Q. Ma; Ming Chen; Satya P. Singh; Willie G. Harris

2003-01-01

199

Effect of the ZrCl4 concentration in the (NaCl-KCl)eqiv-UO2Cl2-ZrCl4 melt and the electrolysis current density on the quantitative composition of UO2-ZrO2 cathode deposits. Calculation and experiment  

NASA Astrophysics Data System (ADS)

A method is proposed for calculating the ZrO2 content in the (NaCl-KCl)eqiv-UO2Cl2-ZrCl4 melt. Based on the known composition of a UO2-ZrO2 cathode deposit, the content is calculated at current densities of 0.08-0.63 A/cm2 and ZrCl4 concentrations of 0-12.3 wt %. The calculated and experimental ZrO2 contents in UO2-ZrO2 cathode deposits are in qualitative and adequate quantitative agreement.

Krotov, V. E.; Filatov, E. C.

2014-08-01

200

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

201

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

202

Photo-enhanced chemical wet etching of GaN  

Microsoft Academic Search

In this paper, we report a photo-enhanced chemical etch rate study on two GaN samples of differing structural and electrical quality as a function of the KOH or H3PO4 etch solution molarity. The etch rate of KOH was observed to be higher than that of H3PO4. This was found to be result from the effects of surface band bending, and

C. H. Ko; Y. K. Su; S. J. Chang; W. H. Lan; Jim Webb; M. C. Tu; Y. T. Cherng

2002-01-01

203

Electrical Properties and DC Conductivity of Phosphoric Acid Doped TGS Single Crystals  

Microsoft Academic Search

Properties of phosphoric acid (H3PO4) doped triglycine sulfate (TGSP) grown from aqueous solutions containing 0.1 to 0.5 moles of H3PO4 have been investigated. Composition analysis indicates a very low incorporation of phosphoric acid in the crystal lattice. Large sized crystals of dimension (70 mm × 40 mm × 25 mm) suitable for IR detector are obtained with 0.2 moles of

Aparna Saxena; V. Gupta; V. Gulia; K. Sreenivas

2005-01-01

204

Macroporous Activated Carbon Fibers from Rayon Precursors Impregnated with Phosphoric Acid  

Microsoft Academic Search

Novel activated carbon fibers (ACFs) from rayon precursors impregnated with phosphoric acid (H3PO4), containing abundant macropores (pore size>50 nm), were successfully obtained. The physical properties of these ACFs were examined. The BET surface was obtained; SEM observations showed that the concentration of H3PO4 impregnation strongly influenced the surface morphology and the porous texture of the resulting ACFs. The shape of the

2006-01-01

205

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

PubMed Central

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

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

2014-01-01

206

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

PubMed

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

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

2015-01-01

207

The effects of foliar applied CaCl 2·2H 2O, Ca(OH) 2 and K 2CO 3 combined with the surfactants Glucopon and Plantacare on gas exchange of 1 year old apple ( Malus domestica BORKH.) and broad bean ( Vicia faba L.) leaves  

Microsoft Academic Search

Calcium chloride, calcium hydroxide, potassium carbonate and the alkylpolyglycoside surfactants Glucopon 215 CSUP and Plantacare 12 UP are salts applied to leaves as foliar nutrients and fungicides. These chemicals were sprayed on apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves. Stomatal conductance and rates of net photosynthesis were measured continuously in the light and in the dark

R. Q. Bai; T. K. Schlegel; J. Schönherr; P. W. Masinde

2008-01-01

208

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.

2014-09-01

209

Pyroelectric properties of phosphoric acid-doped TGS single crystals  

NASA Astrophysics Data System (ADS)

Pyroelectric properties of phosphoric acid (H3PO4)-doped triglycine sulfate (TGSP) single crystals grown from solutions containing 0.1-0.5 mol of H3PO4 have been studied. Incorporation of H3PO4 into the crystal lattice is found to induce an internal bias field (Eb) and is observed through the presence of a sustained polarization and pyroelectricity beyond the transition temperature. The internal bias field has been estimated theoretically by fitting the experimentally measured data on temperature dependence of the pyroelectric coefficient (lgr), dielectric constant (egr') and polarization (P). A high Eb value in the range 9 × 103-15.5 × 104 V m-1 is obtained for crystals grown with 0.1-0.5 mol of H3PO4 in the solution, and a specific concentration of 0.2-0.25 mol of H3PO4 in the solution during crystal growth is found to be optimum for a high figure of merit for detectivity, Fd = 428 µC m-2 K-1.

Saxena, Aparna; Fahim, M.; Gupta, Vinay; Sreenivas, K.

2003-12-01

210

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

E-print Network

locally. Nearby are Southwark Cathedral 3 , Tate Modern, City Hall, the Globe Theatre, Hay's Galleria 5 minutes if you continue on to the Greenwood Lecture Theatre. If you need assistance at any point, please

Applebaum, David

211

Gravity and General Relativity at KCL D C Robinson  

E-print Network

carried out at King's since the nineteenth cen- tury. James Clerk Maxwell considered, and rejected on the history of research into gravity at King's, from Maxwell until about 1980, which will focus primarily

Bushnell, Colin J.

212

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

E-print Network

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

Applebaum, David

213

Membrane Localization of the Neuronal K-Cl Cotransporter (K-Cl COT, KCC2) in Rat Cerebellum  

Microsoft Academic Search

.responses was seen after volume changes above 5-10%. In all cases, the effects of changes in cell volume were readily reversible. In contrast, the related KCNQ2 and KCNQ3 channels, which are prominently expressed in neurons, were insensitive to cell volume changes. Incubation of the oocytes with cytochalasin D and experiments with truncated KCNQ1 channels suggested these channels sense cell volume

Kenneth Gagnon; Peter Lauf; Robert Fyffe

214

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

215

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

216

LABORATORY EXPERIMENT 7 The Iodometric Determination of Copper in Brass  

E-print Network

. Dilute with about 25 mL of distilled water, add 0.3 g urea, and boil briefly to eliminate nitrogen oxides of the complex just disappears, and then add 1 mL of 85% H3PO4. Cool to room temperature. Treat each sample

Nazarenko, Alexander

217

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

218

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

219

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

220

Please cite this article in press as: T. Gu, et al., J. Power Sources (2010), doi:10.1016/j.jpowsour.2010.06.063 ARTICLE IN PRESS  

E-print Network

: PolyBenzImidazole High Temperature Membrane Fuel cells PEMFC Adsorption and desorption Phosphoric acidBenzImidazole (PBI)- H3PO4 High Temperature Membrane Electrode Assembly (HT-MEA) are presented over a range) Membrane Electrode Assembly (MEA) has drawn a lot of atten- tion due to its higher operating temperature (i

Van Zee, John W.

221

Supporting Information Ribonuclease-Activated Cancer Prodrug  

E-print Network

NaOH, adding diethylpyrocarbonate to 0.1% v/v, incubating for 1 h at 37 °C, and then autoclaving to an internal insert standard of H3PO4. Preparatory HPLC was performed on an instrument from Shimadzu Prominence

Raines, Ronald T.

222

Dielectric and ferroelectric properties of phosphoric acid doped triglycine sulfate single crystals  

Microsoft Academic Search

Single crystals of triglycine sulfate (TGS) grown with 25–50 mol% phosphoric acid dopant in solution were investigated for their dielectric, ferroelectric and mechanical hardness properties. A 25 mol% of H3PO4 in solution yielded crystals with a large area in the ac plane without any seed crystal. The room temperature (300 K) dielectric constant (??) and tan? in the frequency range

Aparna Saxena; Vinay Gupta; K. Sreenivas

2001-01-01

223

Classes of Chemical Reactions Reactions in aqueous media  

E-print Network

acid, HBr Phosphoric acid, H3PO4 Hydroiodic acid, HI Acetic acid, CH3CO2H Nitric acid, HNO3 CarbonicClasses of Chemical Reactions Reactions in aqueous media · Precipitation reactions · Acid + electrolytes: a substance that conducts an electric current when dissolved in water Acids are donors of H

Zakarian, Armen

224

Effect of Chemical Stabilization by Phosphate Amendment on the Desorption of P and Pb From a Contaminated Soil  

E-print Network

Effect of Chemical Stabilization by Phosphate Amendment on the Desorption of P and Pb From a Contaminated Soil E. M. Cooper, D. G. Strawn, J. T. Sims and B. M. Onken The amendment of Pb contaminated soils contaminated soil treated with H3PO4 synthetic hydroxyapatite (HA), and HCl + K3PO4 was investigated using

Sparks, Donald L.

225

O isotopic composition of CaCO3 measured by continuous ow isotope ratio mass spectrometry  

E-print Network

XL continuous flow isotope ratio mass spectrometer. Conditions for which the H3PO4/CaCO3 reaction spectrometry (DI-IRMS). A mass spectrometer is used to determine the ratio (R) of the heavy isotoped13 C and d18 O isotopic composition of CaCO3 measured by continuous ¯ow isotope ratio mass

226

O Isotopic Composition of CaCO3 Measured by Continuous Flow Isotope Ratio Mass Spectrometry: Statistical Evaluation and  

E-print Network

XL continuous flow isotope ratio mass spectrometer. Conditions for which the H3 PO4 ­ CaCO3 reactiond13 C and d18 O Isotopic Composition of CaCO3 Measured by Continuous Flow Isotope Ratio Mass the stable carbon and oxygen isotope ratios of small samples (400±20 µg) of calcium carbonate. This new

227

Electron impact cross sections for surrogates of DNA sugar phosphate backbone  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

228

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

PubMed Central

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

2014-01-01

229

Development and Pilot Plant Evaluation of Silica Enhanced Lime Sorbents for Dry Flue Gas Desulfurization  

Microsoft Academic Search

EPA’s efforts to develop low cost, retrofitable flue gas cleaning technology include the development of highly reactive sorbents. Recent work addressing lime enhancement and testing at the bench-scale followed by evaluation of the more promising sorbents in a pilot plant are discussed here.The conversion of Ca(OH)2 with SO2 increased several-fold compared with Ca(OH)2 alone when Ca(OH)2 was slurrled with fly

Wojciech Jozewicz; Claus Jorgensen; John C. S. Chang; Charles B. Sedman; Theodore G. Brna

1988-01-01

230

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

NASA Astrophysics Data System (ADS)

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

Kaur, Kamaldip; Mittal, Raj

2014-12-01

231

Efecto de la concentración de hidróxido de calcio y tiempo de cocción del grano de maíz (Zea mays L.) nixtamalizado, sobre las características fisicoquímicas y reológicas del nixtamal  

Microsoft Academic Search

SUMMARY. Effect of calcium hydroxide concentration and cooking time of corn grain (Zea mays L.) nixtamalized, over physi- cochemical and rheological nixtamal characteristics. The effect of calcium hydroxide (Ca(OH) 2 ) concentration and cooking time on physicochemical and pasting properties of maize, during traditional nixtamalization was evaluated. It was observed that the higher the Ca(OH) 2 concentration and cooking time

2009-01-01

232

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

233

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

PubMed

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

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

2012-05-01

234

Effect of preparation conditions of activated carbon from bamboo waste for real textile wastewater.  

PubMed

This study deals with the use of activated carbon prepared from bamboo waste (BMAC), as an adsorbent for the removal of chemical oxygen demand (COD) and color of cotton textile mill wastewater. Bamboo waste was used to prepare activated carbon by chemical activation using phosphoric acid (H(3)PO(4)) as chemical agent. The effects of three preparation variables activation temperature, activation time and H(3)PO(4):precursor (wt%) impregnation ratio on the color and COD removal were investigated. Based on the central composite design (CCD) and quadratic models were developed to correlate the preparation variables to the color and COD. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The optimum condition was obtained by using temperature of 556 degrees C, activation time of 2.33 h and chemical impregnation ratio of 5.24, which resulted in 93.08% of color and 73.98% of COD. PMID:19765899

Ahmad, A A; Hameed, B H

2010-01-15

235

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

236

Calcium hydroxide promotes cementogenesis and induces cementoblastic differentiation of mesenchymal periodontal ligament cells in a CEMP1- and ERK-dependent manner.  

PubMed

Periodontal tissue engineering is a complex process requiring the regeneration of bone, cementum, and periodontal ligament (PDL). Since cementum regeneration is poorly understood, we used a dog model of dental pulpal necrosis and in vitro cellular wounding and mineralization assays to determine the mechanism of action of calcium hydroxide, Ca(OH)(2), in cementogenesis. Laser capture microdissection (LCM) followed by qRT-PCR were used to assay responses of periapical tissues to Ca(OH)(2) treatment. Additionally, viability, proliferation, migration, and mineralization responses of human mesenchymal PDL cells to Ca(OH)(2) were assayed. Finally, biochemical inhibitors and siRNA were used to investigate Ca(OH)(2)-mediated signaling in PDL cell differentiation. In vivo, Ca(OH)(2)-treated teeth formed a neocementum in a STRO-1- and cementum protein-1 (CEMP1)-positive cellular environment. LCM-harvested tissues adjacent to the neocementum exhibited higher mRNA levels for CEMP1, integrin-binding sialoprotein, and Runx2 than central PDL cells. In vitro, Ca(OH)(2) and CEMP1 promoted STRO-1-positive cell proliferation, migration, and wound closure. Ca(OH)(2) stimulated expression of the cementum-specific proteins CEMP1 and PTPLA/CAP in an ERK-dependent manner. Lastly, Ca(OH)(2) stimulated mineralization by CEMP1-positive cells. Blocking CEMP1 and ERK function abolished Ca(OH)(2)-induced mineralization, confirming a role for CEMP1 and ERK in the process. Ca(OH)(2) promotes cementogenesis and recruits STRO-1-positive mesenchymal PDL cells to undergo cementoblastic differentiation and mineralization via a CEMP1- and ERK-dependent pathway. PMID:20440482

Paula-Silva, Francisco Wanderley Garcia; Ghosh, Abhijit; Arzate, Higinio; Kapila, Sunil; da Silva, Léa Assed Bezerra; Kapila, Yvonne Lorraine

2010-08-01

237

Use of IR Spectroscopy, X-Ray Diffraction, and Petrographic Analysis to Evaluate Structural Changes in Aluminophosphate Compositions at Creeping  

Microsoft Academic Search

The present study is an attempt to evaluate the structural changes observed in ceramic compositions based on aluminum oxide and phosphate H3PO4binders at creeping using IR spectroscopy, X-ray diffraction, and pectrographic analysis. The study reports the dependence of structural changes on the composition of the compounds, the type of phosphate binder, the temperature of processing, and the test conditions at

U. Shayachmetov; R. Shayachmetov; I. Dranca

2001-01-01

238

Vertical Oxide Homojunction TFTs of 0.8 V Gated by Treated Nanogranular Dielectric  

Microsoft Academic Search

Inorganic solid-state electrolyte film based on H3PO4-treated nanogranular SiO2 with high specific capacitance (8 ?F\\/cm2) is developed for vertical indium-tin-oxide (ITO) homojunction thin-film transistors (TFTs) fabrication. Such proton conductor reduces the operating voltage of the vertical homojunction TFTs to 0.8 V due to the enhanced electric-double-layer capacitance. Vertical ITO TFTs gated by such dielectric exhibit a good performance, such as

Jie Jiang; Jia Sun; Bin Zhou; Aixia Lu; Qing Wan

2010-01-01

239

Zirconium phosphate as the proton conducting material in direct hydrocarbon polymer electrolyte membrane fuel cells operating above the boiling point of water  

Microsoft Academic Search

Zirconium phosphate (ZrP) was investigated as a possible proton conductor material in direct hydrocarbon polymer electrolyte membrane (PEM) fuel cells that operate at greater temperatures than conventional PEM fuel cells. Amorphous zirconium phosphate was synthesized in this work by precipitation at room temperature via reaction of ZrOCl2 with H3PO4 aqueous solutions. The conductivity of the synthesized ZrP materials were 7.04×10?5Scm?1

Amani Al-Othman; André Y. Tremblay; Wendy Pell; Sadok Letaief; Tara J. Burchell; Brant A. Peppley; Marten Ternan

2010-01-01

240

The mechanism for soluble phosphates to improve the water resistance of magnesium oxychloride cement  

Microsoft Academic Search

This paper discusses the reasons why the addition of some soluble phosphates to magnesium oxychloride cement (MOC) can greatly improve its water resistance. With the XRD analysis and the determination of the strength retention coefficients (a judging index for the water resistance), it has been shown that the addition of small quantity of the soluble phosphates, such as H3PO4, NaH2PO4·2H2O,

Dehua Deng

2003-01-01

241

Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study13  

Microsoft Academic Search

Background: Soft drink consumption may have adverse effects on bonemineraldensity(BMD),butstudieshaveshownmixedresults. In addition to displacing healthier beverages, colas contain caffeine and phosphoric acid (H3PO4), which may adversely affect bone. Objective: We hypothesized that consumption of cola is associated with lower BMD. Design: BMD was measured at the spine and 3 hip sites in 1413 women and 1125 men in the Framingham

Katherine L Tucker; Kyoko Morita; Ning Qiao; Marian T Hannan; L Adrienne Cupples; Douglas P Kiel

242

Synergistic inhibition effect of rare earth cerium(IV) ion and sodium oleate on the corrosion of cold rolled steel in phosphoric acid solution  

Microsoft Academic Search

The synergistic inhibition effect of rare earth cerium(IV) ion (Ce4+) and sodium oleate (SO) on the corrosion of cold rolled steel (CRS) in 3.0M phosphoric acid (H3PO4) has been investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) methods. The results reveal that SO has a moderate inhibitive effect and its adsorption obeys Temkin

Xianghong Li; Shuduan Deng; Hui Fu; Guannan Mu

2010-01-01

243

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

244

Acid degradation of starch. The effect of acid and starch type  

Microsoft Academic Search

Starch from cereals (wheat, maize and finger millet) pulses (chick pea and green gram), tuber (potato) and root (tapioca) was modified with different acids (0.5N, 1.5h, 50°C). Molecular weight (number average, M?n) of these starches decreased after modification, H3PO4 causing the least and HCl and HNO3 the highest reduction. Gel permeation chromatography of native starches using Sepharose CL 4B gave

V. Singh; S. Z. Ali

2000-01-01

245

Scanning Kelvin force microscopy imaging of surface potential variations near threading dislocations in GaN  

Microsoft Academic Search

Scanning Kelvin force microscopy is applied to study the charge nature of threading dislocations on GaN surfaces. On the oxidized surface, the surface potential maps show little change near dislocations, indicating that if the dislocations are charged in the bulk, the charges are either screened or depleted due to band bending. After cleaning in hot H3PO4, the potential near dislocations

J. W. P. Hsu; H. M. Ng; A. M. Sergent; S. N. G. Chu

2002-01-01

246

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

Microsoft Academic Search

The partial substitution of sulphate (SO42-) by phosphate (PO43-) in triglycine sulfate (TGS) single crystal can improve the properties of the TGS family crystal as room temperature infrared (IR) detector. Phosphoric acid (H3PO4)-doped triglycine sulfate (TGSP) single crystal has strong pyroelectric properties due to its high pyroelectric coefficient and reasonably low dielectric constant. This family of single crystals can grow

R. Malekfar; B. Abbasi

2005-01-01

247

Development of value-added products from alumina industry mineral wastes using low-temperature-setting phosphate ceramics  

Microsoft Academic Search

A room-temperature process for stabilizing mineral waste streams has been developed, based on acid-base reaction between MgO and H3PO4 or acid phosphate solution. The resulting waste form sets into a hard ceramic in a few hours. In this way, various alumina industry wastes, such as red mud and treated potliner waste, can be solidified into ceramics which can be used

A. S. Wagh; Seung-Young Jeong; D. Singh

1996-01-01

248

Output power enhancements of nitride-based light-emitting diodes with inverted pyramid sidewalls structure  

Microsoft Academic Search

This study presents nitride-based light-emitting diodes (LEDs) with inverted pyramid sidewalls by chemical wet etching nitride epitaxial layers and investigates the chemical wet etching mechanism of inverted pyramid sidewalls. It is well known that chemical etching solutions such as KOH, H2SO4 and H3PO4, to selectively etch the N-face GaN but not the Ga-face GaN. In this study, the N-face GaN

Li-Chuan Chang; Cheng-Huang Kuo; Chi-Wen Kuo

2011-01-01

249

Observation of Reversible Pore Change in Mesoporous Tin Phosphate Anode Material during Li Alloying/Dealloying  

E-print Network

was prepared by mixing 9.0 g SnF2 and 12 g H3PO4 followed by dissolution in distilled-deionized water DDW, washed with distilled water and ethanol, and vacuum-dried at 100°C for 10 h. The powders were annealed at 500°C for 5 h, yielding a mesoporous tin phosphate phase. The procedure for assembling a coin

Cho, Jaephil

250

Activated Carbon Production from Date Stones Using Phosphoric Acid  

Microsoft Academic Search

The effects of activation time and activation temperature on the yield and the adsorptive capacity towards iodine were studied. The yield and the quality of the activated carbon prepared by using H3PO4 were compared with that prepared from date stones using the same equipment, and under similar conditions by using ZnCl2 as an oxidizing agent. The iodine number for the

F. Al-Qaessi; L. Abu-Farah

2010-01-01

251

Effect of activation method on the pore structure of activated carbon from date pits application to the treatment of water  

Microsoft Academic Search

Four active carbons have been prepared by carbonisation without adjuvant (DC) and by chemical activation of date pits with ZnCl2 (DZ), KOH (DK), and H3PO4 (DP) in order to show the effect of variables such as the nature of the chemical reagent, extent of impregnation on the adsorbent surface area, and porosity of the resulting activated carbons. The pore structure

Zoulikha Merzougui; Yacine Azoudj; Naima Bouchemel; Fatima Addoun

2011-01-01

252

Porosity development in activated carbons obtained from date pits under chemical activation with phosphoric acid  

Microsoft Academic Search

Date pits, a low-cost agricultural by-product, was tested as a precursor for the production of porous carbons in a chemical scheme using phosphoric acid. The raw material was impregnated with increasing concentrations of H3PO4 (30–70 vol.%) followed by pyrolysis at 300, 500 or 700 °C. Texture characteristics of the products were determined by adsorption of N2 at 77 K, as

Badie S. Girgis; Abdel-Nasser A. El-Hendawy

2002-01-01

253

Development of samarium [ 32P] phosphate colloid for radiosynoviorthesis applications: Preparation, biological and preliminary clinical studies experience  

Microsoft Academic Search

A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl3 carrier with carrier added [32P]H3PO4 in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for

G. Prabhakar; Satbir S. Sachdev; S. Umamaheswari; N. Sivaprasad; Manohar H. Bhatia; Pradip R. Chaudhari; Srikant V. Solav

2007-01-01

254

Mechanistic investigation of phosphate ester bond cleavages of glycylphosphoserinyltryptophan radical cations under low-energy collision-induced dissociation.  

PubMed

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](+)/[z(1) - 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](•+). PMID:23516067

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

2013-04-01

255

Extraction of arsenic species from airborne particulate filters—Application to an industrial area of Greece  

Microsoft Academic Search

In the present study, the extraction of the arsenic species arsenite (As(III)), arsenate (As(V)), monomethyarsonic (MMA) and dimethylarsinic acid (DMA) from airborne particulate filters was investigated and optimized. For this purpose, total suspended particulate matter as well as size fractionated aerosol samples were collected from the industrial area of Aspropyrgos, Greece, in glass fibre and polycarbonated filters, respectively. Among H3PO4

Fotios Tsopelas; Lambrini-Areti Tsakanika; Maria Ochsenkühn-Petropoulou

2008-01-01

256

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

257

Fabrication of the ZnO thin films using wet-chemical etching processes on application for organic light emitting diode (OLED) devices  

E-print Network

light emitting diode (OLED) devices D.-G. Yoo a , S.-H. Nam a , M.H. Kim a , S.H. Jeong a , H.-G. Jee to fabricate ZnO-based OLED devices, various etchants such as HCl, HNO3, H2SO4 and H3PO4 have been studies- sively used in solar cells, touch panels, heat mirrors, organic electro- luminescence devices (OLED

Boo, Jin-Hyo

258

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

E-print Network

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

259

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. PMID:25025557

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

2014-01-01

260

Growth of calcium phosphate on phosphorylated chitin fibres  

Microsoft Academic Search

Calcium phosphate growth on chitin phosphorylated fibres was studied using scanning electron microscopy and energy dispersive X-ray analysis (SEM, EDX), micro-Fourier transform infrared spectroscopy (FTIR), and solid state magic angle spinning nuclear magnetic resonance (MAS NMR) techniques. The C6 chemical shift positions of 13C MAS NMR in the chitin fibres phosphorylated using urea and H3PO4 are obvious indicating that phosphorylation

Y. YOKOGAWA; J PAZ REYES; M. R MUCALO; M TORIYAMA; Y KAWAMOTO; T SUZUKI; K NISHIZAWA; F NAGATA; T KAMAYAMA

1997-01-01

261

Exposure damage mechanisms for KCl windows in high power laser systems  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

262

A study of some effects of magnetic and electric fields on LiF and KCl  

E-print Network

A STUDY OF SOME EFFECTS OF MAGNETIC AND ELECTRIC FIELDS ON LiF AND KC1 A Thesis By JAMES EDWARD MILLER Submitted to the Graduate College of the Texas ARM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1966 Major Subject: Physics A STUDY OF SOME EFFECTS OF MAGNETIC AND ELECTRIC FIELDS ON LiF AND KC1 A Thesis By JAMES EDWARD MILLER Approved as to style and content by: haarman o Co attee ead o Department Member ber Member May 1966...

Miller, James Edward

2012-06-07

263

Anodic dissolution of irradiated metallic fuels in LiCl-KCl melt  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

264

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

SciTech Connect

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

Hikino, S.; Xie, G.; Ema, K.; Ito, Y. (Dept. of Nuclear Engineering, Faculty of Engineering, Kyoto Univ., Sakyo-ku, Kyoto 606 (JP)); Shou, Z.M. (Changchun Inst. of Applied Chemistry, Academia Sinica, Changchun 130022 (CN))

1992-07-01

265

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

SciTech Connect

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

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

2012-10-01

266

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

PubMed Central

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

Zareidoost, Amir; Ghaseme, Behrooz

2012-01-01

267

Improving the Selectivity of the Phosphoric Acid ?-Elimination on a Biotinylated Phosphopeptide  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

268

Formation and Dissociation of Phosphorylated Peptide Radical Cations  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

269

Characteristics of microporous/mesoporous carbons prepared from rice husk under base- and acid-treated conditions.  

PubMed

The study reports the preparation of activated carbon with a high surface area from rice husk using chemical activation with H(3)PO(4) and ZnCl(2). Activated carbon prepared from rice husk usually exhibits low specific surface areas due to its high ash content. However, experimental results show that base-leaching and acid-washing processes can effectively enhance the adsorption capacity of rice-husk carbon. The study also investigates the effects of preparation parameters on the surface characteristics of the carbon. These parameters include the kind of activating agent, before and after treatment procedures, impregnation ratio and activation temperature. The chemical and physical properties of samples were examined by EA, ICP-MS, XRD, FTIR, SEM and a N(2)-adsorption meter. The surface areas obtained from ZnCl(2) and H(3)PO(4) activation are as high as 2434 and 1741 m(2)/g, respectively. These values are higher than that of activated carbon treated with neither base nor acid (1262 and 508 m(2)/g for ZnCl(2) and H(3)PO(4) activation). Thermogravimetric analysis shows that the activation process can be divided into three parts based on temperature zones. The results of this study will be useful in developing resource recovery systems for agricultural biomass. PMID:19595505

Liou, Tzong-Horng; Wu, Shao-Jung

2009-11-15

270

Influence of inorganic salts on the primary pyrolysis products of cellulose.  

PubMed

Processing bio-oil with the help of currently existing petroleum refinery infrastructure has been considered as a promising alternative to produce sustainable fuels in the future. The feasibility of bio-oil production and upgrading processes depend upon its chemical composition which in turn depends on the biomass composition and the process conditions of the fast pyrolysis reactions. The primary goal of this paper was to investigate the effect of mineral salts including mixtures of salts in the form of switchgrass ash on the chemical speciation resulting from primary pyrolysis reactions of cellulose and to gain an insight of the underlying mechanisms. Various concentrations of inorganic salts (NaCl, KCl, MgCl(2), CaCl(2), Ca(OH)(2), Ca(NO(3))(2), CaCO(3) and CaHPO(4)) and switchgrass ash were impregnated on pure cellulose. These samples were pyrolyzed in a micro-pyrolyzer connected to a GC-MS/FID system. Effects of minerals on the formation of (a) low molecular weight species - formic acid, glycolaldehyde and acetol, (b) furan ring derivatives - 2-furaldehyde and 5-hydroxy methyl furfural and (c) anhydro sugar - levoglucosan are reported exclusively. Further, the effect of reaction temperature ranging from 350 to 600 degrees C on the pyrolysis speciation of pure and ash-doped cellulose is also reported. The pyrolysis speciation revealed the competitive nature of the primary reactions. Mineral salts and higher temperatures accelerated the reactions that led to the formation of low molecular weight species from cellulose as compared to those leading to anhydro sugars. PMID:20171877

Patwardhan, Pushkaraj R; Satrio, Justinus A; Brown, Robert C; Shanks, Brent H

2010-06-01

271

Zinc, copper, and nickel availabilities as determined by soil solution and DTPA extraction of a sludge?amended soil  

Microsoft Academic Search

Extracting sludge?amended soil with DTPA does not always give a reliable measure of plant?available heavy metals. The major purpose of this greenhouse pot study was to help explain why. Two anaerobically digested sludges from sewages treated with either Ca(OH)2or FeCl3were applied to 3?kg samples of a Mollic Albaqualf previously limed with Ca(OH)2rates of 0, 2.5, and 10g\\/pot that resulted in

J. F. Adams; D. E. Kissel

1989-01-01

272

Nickel Hydroxide as an Active Material for the Positive Electrode in Rechargeable Alkaline Batteries  

Microsoft Academic Search

Spherical nickel hydroxide powders coprecipitated with the additives Ca(OH)2, Co(OH)2, and Zn(OH)2 were prepared through a spraying technique. These powders, which have a higher tapping density and a much smaller pore volume and crystalline size than conventional powders, were used as the active materials of nickel hydroxide electrodes. The effects of the Ca(OH)2, Co(OH)2, and Zn(OH)2 additions on electrode properties

J. Chen; D. H. Bradhurst; S. X. Dou; H. K. Liu

1999-01-01

273

Simultaneous removal of cadmium and turbidity in contaminated soil-washing water by DAF and electroflotation  

Microsoft Academic Search

The removal of cadmium and turbidity from contaminated soil-washing water was studied by dissolved air flotation (DAF) and electroflotation at laboratory scale by using sodium lauryl sulfate (SLS) as an anionic surfactant, and calcium hydroxide (Ca(OH)2) as a coagulant. Using DAF, and in the presence of SLS or Ca(OH)2, the maximum recovery rate of cadmium obtained at a stoichiometric cadmium

Y. Jung; M. Han; S. Lee

274

Fuel production from waste vehicle tires by catalytic pyrolysis and its application in a diesel engine  

Microsoft Academic Search

An alternative fuel production was performed by pyrolysis of waste vehicle tires under nitrogen (N2) environment and with calcium hydroxide (Ca(OH)2) as catalyst. The sulfur content of liquids obtained were reduced by using Ca(OH)2. The liquid fuel of waste vehicle tires(TF) was then used in a diesel engine to blend with petroleum diesel fuel by 5%(TF5), 10%(TF10), 15%(TF15), 25%(TF25), 35%(TF35),

Cumali ?lk?l?ç; Hüseyin Ayd?n

2011-01-01

275

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

PubMed

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

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

2015-03-01

276

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

PubMed

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

Ishiguro, Maki; Endo, Takashi

2015-02-01

277

Deafness and renal tubular acidosis in mice lacking the K-Cl co-transporter Kcc4  

Microsoft Academic Search

Hearing depends on a high K+ concentration bathing the apical membranes of sensory hair cells. K+ that has entered hair cells through apical mechanosensitive channels is transported to the stria vascularis for re-secretion into the scala media. K+ probably exits outer hair cells by KCNQ4 K+ channels, and is then transported-by means of a gap junction system connecting supporting Deiters'

Thomas Boettger; Christian A. Hübner; Hannes Maier; Marco B. Rust; Franz X. Beck; Thomas J. Jentsch

2002-01-01

278

Modeling of anodic dissolution of U Pu Zr ternary alloy in the molten LiCl KCl electrolyte  

NASA Astrophysics Data System (ADS)

The metallic fuel anode in the molten salt electrorefining step for the pyrometallurgical reprocessing was modeled based on the findings from the anodic dissolution tests using a U Pu Zr ternary alloy. This anode model simulates selective dissolution of uranium and plutonium at lower anode potential, growth of a diffusion controlling layer consisting of a mixture of the molten salt electrolyte and the remaining zirconium metal, and simultaneous dissolution of all the constituents at higher anode potential. The calculation with this model reproduced well the actual anodic behavior of the U Pu Zr ternary alloy such as two-step rapid rise in the anode potential.

Iizuka, Masatoshi; Kinoshita, Kensuke; Koyama, Tadafumi

2005-02-01

279

Electrochemical behaviors of the magnesium alloy substrates in various pretreatment solutions  

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

280

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

PubMed

The urgent need for alternative renewable energies to supplement petroleum-based fuels and the reduction of landfill sites for disposal of solid wastes makes it increasingly attractive to produce inexpensive biofuels from the organic fraction of the municipal solid waste. Therefore, municipal waste in the form of newspaper was investigated as a potential feedstock for fermentable sugars production. Hydrolysis of newspaper by dilute phosphoric acid was carried out in autoclave Parr reactor, where reactor temperature and acid concentration were examined. Xylose concentration reached a maximum value of 14 g/100 g dry mass corresponding to a yield of 94% at the best identified conditions of 2.5 wt% H3PO4, 135 degrees C, 120 min reaction time, and at 2.5 wt% H3PO4, 150 degrees C, and 60 min reaction time. For glucose, an average yield of 26% was obtained at 2.5 wt% H3PO4, 200 degrees C, and 30 min. Furfural and 5-hydroxymethylfurfural (HMF) formation was clearly affected by reaction temperature, where the higher the temperature the higher the formation rate. The maximum furfural formed was an average of 3 g/100 g dry mass, corresponding to a yield of 28%. The kinetic study of the acid hydrolysis was also carried out using the Saeman and the two-fraction models. It was found for both models that the kinetic constants (K) depend on the acid concentration and temperature. The degradation of HMF to levulinic acid is faster than the degradation of furfural to formic acid. Also, the degradation rate is higher than the formation rate for both inhibitors when degradation is observed. PMID:24617059

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

2013-01-01

281

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

282

Facile template-free synthesis of pine needle-like Pd micro/nano-leaves and their associated electro-catalytic activities toward oxidation of formic acid  

PubMed Central

Pine needle-like Pd micro/nano-leaves have been synthesized by a facile, template-free electrochemical method. As-synthesized Pd micro/nano-leaves were directly electrodeposited on an indium tin oxide substrate in the presence of 1.0 mM H2PdCl4 + 0.33 M H3PO4. The formation processes of Pd micro/nano-leaves were revealed by scanning electron microscope, and further characterized by X-ray diffraction and electrochemical analysis. Compared to conventional Pd nanoparticles, as-prepared Pd micro/nano-leaves exhibit superior electrocatalytic activities for the formic acid oxidation. PMID:21711919

2011-01-01

283

The influence of phosphorus and nitrogen on millet and clover growing in soils affected by salinity  

Microsoft Academic Search

Summary  The growth of foxtail millet and clover in soils of varying degrees of salinity (0.5 to 13 mmhos\\/cm), treated with nitrogen\\u000a and phosphorus, was studied. Salinity levels were achieved by addition of sodium chloride. Nitrogen (10 to 60 ppm N) and phosphorus\\u000a (6.4 to 44.8 ppm P) were added as NH4NO3 and H3PO4, respectively.\\u000a \\u000a The growth of millet decreased sharply

S. Ravikovitch; D. Yoles

1971-01-01

284

Determination and Quantitation of Ten Sulfonylurea Herbicides in Soil Samples Using Liquid Chromatography with Electrospray Ionization Mass Spectrometric Detection  

Microsoft Academic Search

A multiresidue method was developed for confirmation and quantitation of ten sulfonylurea herbicides including nicosulfuron, thifensulfuron-methyl, metsulfuron-methyl, sulfometuron-methyl, chlorsulfuron, ethametsulfuron-methyl, tribenuron, bensulfuron-methyl, pyrazosulfuron-ethyl, and chlorimuron-ethyl in soil. Analytes were extracted from the soil sample with methanol-phosphate buffer (2:8, v\\/v) (pH 7.8) in an ultrasonic bath. The extracts were adjusted to pH 2.5 with 85% H3PO4 and passed, under vacuum, through

Guibiao Ye; Wei Zhang; Xin Cui; Canping Pan; Shuren Jiang

2006-01-01

285

The conserved protein kinase-A target motif in synapsin of Drosophilais effectively modified by pre-mRNA editing  

E-print Network

/ml Protease K (10 mg/ml) were added] and incubated for 30 minutes at 68°C. Next, 75 µl 8 M potassium acetate were added followed by standard phenol and EtOH extraction. Finally, the DNA pellet was resuspended in 50 µl TE buffer. RNA preparation Total RNA... ). The papers were washed three times for 15 minutes in 175 mM H3PO4 to remove unbound ATP, before transferring them to scintillation vials containing 3 ml H2O. The amount of radioactive 32P incorporated into the substrate was determined in a scintillation...

Diegelmann, Soren; Nieratschker, Vanessa; Werner, Ursula; Hoppe, Jurgen; Zars, Troy; Buchner, Erich

2006-11-14

286

Transformation mechanism of different chemically precipitated apatitic precursors into ?-tricalcium phosphate upon calcination  

Microsoft Academic Search

The Ca-deficient apatite (CDHA) was prepared from the precursors of (CH3COO)2Ca·xH2O, Ca(NO3)2·4H2O and H3PO4, (NH4)H2PO4 to investigate the transformation mechanism of ?-tricalcium phosphate (?-TCP). X-ray diffraction analysis shows that the development of ?-TCP is not via direct reaction between Ca and P for all the different combinations between Ca and P precursors. The activation energy of ?-TCP formation with (NH4)H2PO4

Sz-Chian Liou; San-Yuan Chen

2002-01-01

287

Investigation on the growth kinetics of KDP:LAP and TGS:LAP single crystals  

Microsoft Academic Search

Potassium dihydrogen phosphate KDP; (KH2PO4) and triglycine sulfate TGS; (CH2NH2COOH.H2SO4), are extensively studied ferroelectric materials, and find wide applications in electrooptic and infrared detecting devices respectively. L-arginine phosphate monohydrate (C6H14N4O2H3PO4.H2O), abbreviated as LAP, is a highly transparent monoclinic crystal with attractive properties for efficient frequency conversion of infrared lasers. Effects of doping KDP and TGS crystals with LAP are investigated.

A. K. Batra; J. Stephens; K. Bhat; M. D. Aggarwal; Burl H. Peterson; Michael Curley; R. B. Lal

2005-01-01

288

Pyroelectric properties of some compounds based on protein aminoacids  

Microsoft Academic Search

Protein aminoacid-based compounds were synthesized, and their single crystals were grown. The dielectric and pyroelectric\\u000a properties of the crystals were studied in the temperature ranges 80–340 and 140–340 K, respectively. It was established that\\u000a three of the compounds studied (L-His(H3PO4)2, L-TyrHCl, L-Ala2H3PO3 H2O) are linear pyroelectrics, with their room-temperature pyroelectric figures of merit being close to those of ferroelectric\\u000a triglycine

V. K. Yarmarkin; S. G. Shul’man; G. A. Pankova; V. V. Lemanov

2005-01-01

289

Analysis and confirmation of synthetic anorexics in adulterated traditional Chinese medicines by high-performance capillary electrophoresis  

Microsoft Academic Search

Six synthetic anorexics, clobenzorex, diethylpropion, fenfluramine, methamphetamine, phenylpropanolamine and phentermine, which can be found as adulterants in traditional Chinese medicines were assayed simultaneously by high-performance capillary electrophoresis. The electrolyte was a buffer solution containing 120 mM phosphate buffer (NaH2PO4\\/H3PO4, pH 2.0) and 15% acetonitrile. Applied voltage was 16 kV and temperature was 30°C. Fluoren-2,7-diammonium chloride was used as an internal

Yoe-Ray Ku; Yuan-Shiun Chang; Kuo-Ching Wen; Li-Kang Ho

1999-01-01

290

Hydrothermal Synthesis of Lithium Zinc Phosphates: Structural Investigation of Twinned ?-Li 4Zn(PO 4) 2 and a High Temperature Polymorph ?-Li 4Zn(PO 4) 2  

Microsoft Academic Search

The system LiOH:Zn(NO3)2:H3PO4:H2O was investigated using hydrothermal synthesis techniques in the temperature range 20°C

T. R. Jensen; R. G. Hazell; A. Nørlund Christensen; J. C. Hanson

2002-01-01

291

Hydrothermal Synthesis of Lithium Zinc Phosphates: Structural Investigation of Twinned alpha-Li4Zn(PO4)2 and a High Temperature Polymorph beta-Li4Zn(PO4)2  

Microsoft Academic Search

The system LiOH:Zn(NO3)2:H3PO4:H2O was investigated using hydrothermal synthesis techniques in the temperature range 20°C

T. R. Jensen; R. G. Hazell; A. Nørlund Christensen; J. C. Hanson

2002-01-01

292

Sonochemical synthesis of the high energy density cathode material VOPO 4·2H 2O  

Microsoft Academic Search

We report on a high energy density VOPO4·2H2O cathode material prepared by the sonochemical method. VOPO4·2H2O is rapidly prepared within 15 min by ultrasonic irradiation of an aqueous solution containing V2O5 and H3PO4. The sonochemically synthesized VOPO4·2H2O forms rectangular polycrystals 1–3?m in size as observed by transmission electron microscopy (TEM) and selected area electron diffraction. X-ray diffraction (XRD) and Fourier

Nam-Gyu Park; Kwang Man Kim; Soon Ho Chang

2001-01-01

293

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

Microsoft Academic Search

Stable high-field anodization (1500-4000 A m-2) for the fabrication of highly ordered porous anodic alumina films has been realized in a H3PO4-H2O-C2H5OH system. By maintaining the self-ordering voltage and adjusting the anodizing current density, high-quality self-ordered alumina films with a controllable inter-pore distance over a large range are achieved. The high anodizing current densities lead to high-speed film growth (4-10

Yanbo Li; Maojun Zheng; Li Ma; Wenzhong Shen

2006-01-01

294

Acetic Acid (H3COOH): GaAs; Pb; Ti Hydrochloric Acid (HCl): Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In; Fe; Pb; Ni; NiO, Ni2O3; Sn;  

E-print Network

; Fe; Pb; Ni; NiO, Ni2O3; Sn; SnO2; Ti; Zn Hydrofluoric Acid (HF): GaAs; Ni; SiO2; Ti Nitric Acid (HNO3 : hydrofluoric acid (49%, aq) HNO3 : nitric acid (70%, aq) H2SO4 : sulfuric acid (96%, aq) H3PO4 : phosphoricAcetic Acid (H3COOH): GaAs; Pb; Ti Hydrochloric Acid (HCl): Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In

Garmestani, Hamid

295

Chemical Analysis and Structural Characterization of Oil Palm Lignins from Black Liquor of Empty Fruit Bunch Fiber Pulping  

Microsoft Academic Search

Oil palm empty fruit bunch (OPEFB) fiber was pulped with 20% KOH-0.1% anthra-quinone at 170°C for 3h. The black liquors were acidified to pH 7.0, 5.5, 5.0, 3.5, and 2.0 with 9.68 N H3PO4, respectively. Polysaccharide degradation products were precipitated in ethanol. Lignin fractions were then recovered from the corresponding super-natants of the black liquor by precipitation at pH 2.0

Runcang Sun; J. Tomkinson; J. Bolton

1999-01-01

296

Comparison of calcium hydroxide removal by self-adjusting file, EndoVac, and CanalBrush agitation techniques: An in vitro study  

PubMed Central

Objectives: This study comparatively evaluated the efficacy of self-adjusting file (SAF), Endovac, and CanalBrush irrigant agitation protocols in removing calcium hydroxide (Ca(OH)2) from the root canals. Materials and Methods: Sixty extracted human mandibular canine teeth were instrumented with ProTaper rotary instruments to size #40 and dressed with Ca(OH)2. The roots were randomly assigned to four groups according to irrigant agitation protocol used (n = 15). In Group 1: Conventional syringe irrigation (no activation, control); Group 2: Rotary brush agitation (CanalBrush); Group 3: Apical negative pressure irrigation (EndoVac system); and Group 4: Sonic agitation (SAF) were used. Scanning electron microscopic (SEM) evaluation was done for assessment of Ca(OH)2 removal in the coronal and apical thirds. Statistical analysis was performed by Wilcoxon and Kruskal-Wallis tests. Results: There were statistically significant differences among the groups (P = 0.218). A statistically significant difference was seen between the test groups in Ca(OH)2 removal from the apical third of the canal (P < 0.05). In the coronal third, there was no difference between the groups (P > 0.05). The most efficient Ca(OH)2 removal in apical third was recorded in Group 3 (EndoVac) and Group 4 (SAF) (P < 0.05). In Group 4 (sonic agitation), there was no significantly difference between Ca(OH)2 removal in coronal and apical thirds. Conclusions: SAF and EndoVac showed significantly better performance than CanalBrush and conventional syringe irrigation in removing Ca(OH)2 from apical third of the root canals. PMID:24082574

Türker, Sevinç Aktemur; Koçak, Mustafa Murat; Koçak, Sibel; Sa?lam, Baran Can

2013-01-01

297

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

PubMed

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

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

2009-10-15

298

Aripiprazole salts IV. Anionic plus solvato networks defining molecular conformation  

NASA Astrophysics Data System (ADS)

Five new examples of aripiprazole (arip) salts are presented, viz., the Harip phthalate [Harip+·C8H5O4-(I)], homophthalate [Harip+·C9H7O4-(II)] and thiosalicilate [Harip+·C7H4O2S-(III)] salts on one side, and two different dihidrogenphosphates, Harip+·H2PO4-·2(H3PO4)·H2O (IV) and Harip+·H2PO4-·H3PO4(V). Regarding the internal structure of the aripH+ cations, they do not differ from the already known moieties in bond distances and angles, while interesting differences in conformation can be observed, setting them apart in two groups: those in I, II and III present similar conformations to those in the so far reported arip salts presenting the same centrosymmetric R(8)22 dimeric synthon, but different to those in IV and V. In parallel, the anion (+ acid) groups define bulky systems of different dimensionality (1D in the former group, 2D in the latter). The correlation between arip molecular conformation and anionic network type is discussed. An interesting feature arises with the water solvato molecule in IV, disordered around an inversion center, in regard with its interaction with an (also disordered) phosphato O-H, in a way that an “orderly disordered” H-bonding scheme arises, complying with the S.G. symmetry requirements only on average.

Freire, Eleonora; Polla, Griselda; Baggio, Ricardo

2014-06-01

299

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

300

Imparting high proton conductivity to a metal-organic framework material by controlled acid impregnation.  

PubMed

The extensive implementation of hydrogen-powered technology today is limited by a number of fundamental problems related to materials research. Fuel-cell hydrogen conversion technology requires proton-conducting materials with high conductivity at intermediate temperatures up to 120 °C. The development of such materials remains challenging because the proton transport of many promising candidates is based on extended microstructures of water molecules, which deteriorate at temperatures above the boiling point. Here we show the impregnation of the mesoporous metal-organic framework (MOF) MIL-101 by nonvolatile acids H(2)SO(4) and H(3)PO(4). Such a simple approach affords solid materials with potent proton-conducting properties at moderate temperatures, which is critically important for the proper function of on-board automobile fuel cells. The proton conductivities of the H(2)SO(4)@MIL-101 and H(3)PO(4)@MIL-101 at T = 150 °C and low humidity outperform those of any other MOF-based materials and could be compared with the best proton conductors, such as Nafion. PMID:22958118

Ponomareva, Valentina G; Kovalenko, Konstantin A; Chupakhin, Alexei P; Dybtsev, Danil N; Shutova, Elena S; Fedin, Vladimir P

2012-09-26

301

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

NASA Astrophysics Data System (ADS)

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

Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

2014-04-01

302

Effect of phosphoric acid pretreatment of corncobs on the fermentability of Clostridium beijerinckii TISTR 1461 for biobutanol production.  

PubMed

Corncobs pretreated with H2SO4, HNO3, and H3PO4 were compared to evaluate the fermentation ability of Clostridium beijerinckii TISTR 1461 to produce biobutanol via acetone-butanol-ethanol (ABE) fermentation. It was found that the hydrolysate from H3PO4 pretreatment could be used as a substrate without any inhibitor removal methods. However, in terms of sugar yield, it gave the lowest total sugars in both pretreatment and enzymatic hydrolysis. Response surface methodology was applied to optimize enzymatic hydrolysis of the pretreated corncobs. The optimized conditions reduced the consumption of enzymes and hydrolysis time to 7.68 FPU/g biomass and 63.88 hr, respectively, and yielded 51.82 g/L reducing sugars. The Celluclast 1.5 L and Novozyme 188 enzyme ratio were varied to maximize the hydrolyzed sugars. The ABE fermentation, using substrate from phosphoric acid pretreatment of corncobs, with 10 g/L glucose supplementation produced 11.64 g/L of total ABE, which was close to the control experiment using synthetic medium. This study showed that corncobs pretreated with phosphoric acid could potentially be used as a substrate without using a detoxification process. PMID:24678653

Boonsombuti, Akarin; Luengnaruemitchai, Apanee; Wongkasemjit, Sujitra

2015-01-01

303

All-solid-state reduced graphene oxide supercapacitor with large volumetric capacitance and ultralong stability prepared by electrophoretic deposition method.  

PubMed

Portable energy storage devices have gained special attention due to the growing demand for portable electronics. Herein, an all-solid-state supercapacitor is successfully fabricated based on a poly(vinyl alcohol)-H3PO4 (PVA-H3PO4) polymer electrolyte and a reduced graphene oxide (RGO) membrane electrode prepared by electrophoretic deposition (EPD). The RGO electrode fabricated by EPD contains an in-plane layer-by-layer alignment and a moderate porosity that accommodate the electrolyte ions. The all-solid-state RGO supercapacitor is thoroughly tested to give high specific volumetric capacitance (108 F cm(-3)) and excellent energy and power densities (7.5 Wh cm(-3) and 2.9 W cm(-3), respectively). In addition, the all-solid-state RGO supercapacitor exhibits an ultralong lifetime for as long as 180 days (335?000 cycles), which is an ultrahigh cycling capability for a solid-state supercapacitor. The RGO is also tested for being used as a transparent supercapacitor electrode demonstrating its possible use in various transparent optoelectronic devices. Due to the facile scale-up capability of the EPD process and RGO dispersion, the developed all-solid-state supercapacitor is highly applicable to large-area portable energy storage devices. PMID:25545033

Wang, Mei; Duong, Le Dai; Mai, Nguyen Thi; Kim, Sanghoon; Kim, Youngjun; Seo, Heewon; Kim, Ye Chan; Jang, Woojin; Lee, Youngkwan; Suhr, Jonghwan; Nam, Jae-Do

2015-01-21

304

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

305

Effect of the Basic Residue on the Energetics and Dynamics of Dissociation of Phosphopeptides  

SciTech Connect

Time- and collision-energy-resolved surface-induced dissociation (SID) of protonated peptides containing phosphoserine (s) was studied using a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer configured for SID experiments. We examined fragmentation of three singly protonated peptides: GGGsGGG, KGGsGGG, and RGGsGGG. Fragmentation of GGGsGGG occurs under the mobile proton condition, while the ionizing proton is sequestered by the basic residue, resulting in the nonmobile proton condition in dissociation of the two basic peptides: KGGsGGG and RGGsGGG. RRKM modeling of the experimental data demonstrates that the energetics and dynamics of H3PO4 loss are different under mobile and nonmobile proton conditions. Specifically, fragmentation of GGGsGGG is characterized by a higher dissociation barrier, 1.68 eV, and higher activation entropy, 11 e.u. (e.u. = entropy unit), than fragmentation of the basic peptides. Similar threshold energies of 1.36 eV and 1.40 eV and activation entropies of -4.9 e.u. and 0.3 e.u. were obtained for KGGsGGG and RGGsGGG, respectively. We propose that the loss of H3PO4 from phosphoserine is a two-step process, in which the phosphate abstraction from the phosphorylated side chain is followed by dissociation of the ion-molecule complex.

Laskin, Julia; Kong, Ricky; Song, Tao; Chu, Ivan K.

2012-12-15

306

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

307

A simplified etching technique to improve the adhesion of fiber post  

PubMed Central

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

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

2014-01-01

308

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

PubMed

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

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

2015-01-01

309

A Composite Membrane of Caesium Salt of Heteropolyacids/Quaternary Diazabicyclo-Octane Polysulfone with Poly (Tetrafluoroethylene) for Intermediate Temperature Fuel Cells  

PubMed Central

Inorganic-organic composite electrolyte membranes were fabricated from CsXH3?XPMo12O40 (CsPOMo) and quaternary diazabicyclo-octane polysulfone (QDPSU) using a polytetrafluoroethylene (PTFE) porous matrix for the application of intermediate temperature fuel cells. The CsPOMo/QDPSU/PTFE composite membrane was made proton conducting by using a relatively low phosphoric acid loading, which benefits the stability of the membrane conductivity and the mechanical strength. The casting method was used in order to build a thin and robust composite membrane. The resulting composite membrane films were characterised in terms of the elemental composition, membrane structure and morphology by EDX, FTIR and SEM. The proton conductivity of the membrane was 0.04 S cm?1 with a H3PO4 loading level of 1.8 PRU (amount of H3PO4 per repeat unit of polymer QDPSU). The fuel cell performance with the membrane gave a peak power density of 240 mW cm?2 at 150 °C and atmospheric pressure. PMID:24958287

Xu, Chenxi; Wang, Xu; Wu, Xu; Cao, Yuancheng; Scott, Keith

2012-01-01

310

Repetitive injection field-amplified sample stacking for cationic compounds determination.  

PubMed

The development of a field-amplified sample stacking technique is presented. Sensitivity enhancement in this technique was obtained by repetitive injections of a sample followed by steps of sample matrix removal through the application of counter-pressure. Under optimized conditions the background electrolyte (BGE) was composed of 80 mM H3PO4 while the sample matrix contained 0.5mM H3PO4 and 30% (v/v) methanol. The elaborated method enabled a 4-fold effective injection of the sample (53 s, 0.5 psi). Each injection was followed by a focusing step during which the application of a voltage (2 kV) and counter-pressure (-1 psi) was performed for 0.65 min. The method was developed for the determination of six psychiatric drugs (opipramol, hydroxyzine, promazine, amitriptyline, fluoxetine, and thioridazine). The elaborated method was applied for analysis of human urine samples after a simple liquid-liquid extraction procedure. The detection limits obtained were in the range of 2.23-6.21 ng/mL. PMID:24840407

Dziomba, Szymon; Biernacki, Micha?; Ol?dzka, Ilona; Skrzydlewska, El?bieta; B?czek, Tomasz; Kowalski, Piotr

2014-07-01

311

The use of piassava fibers (Attalea funifera) in the preparation of activated carbon.  

PubMed

The piassava fiber, residue of the broom industry, was used as precursor for the preparation of activated carbons (AC). AC were prepared by chemical activation with zinc chloride (AC ZnCl(2)) or phosphoric acid (AC H(3)PO(4)) and by physical activation with carbon dioxide (AC CO(2)) or water vapor (AC H(2)O). These materials were characterized by adsorption/desorption of N(2) to determine the BET areas, elemental analysis (CHN), thermogravimetric analysis (TG, DTA) and scanning electron microscopy (SEM). The carbons were tested with respect to their adsorption capacity of methylene blue, reactive red, phenol and metallic ions (Cr(+6), Cu(+2) and Zn(+2)). AC ZnCl(2) presented the highest surface area (1190 m(2)g(-1)) and AC H(3)PO(4), the largest pore volume (0.543 cm(3)g(-1)). AC ZnCl(2) was more efficient in the adsorption of methylene blue, Cr(+6) and Cu(+2) ions. AC H(2)O was the better adsorbent for phenol, while AC CO(2) was better for Zn(+2) ions. PMID:20172713

Avelar, Fabiana Ferreira; Bianchi, Maria Lúcia; Gonçalves, Maraisa; da Mota, Estella Gaspar

2010-06-01

312

The influence of impurities on phosphoric acid hemihydrate crystallization  

NASA Astrophysics Data System (ADS)

The influence of four typical impurities on phosphoric acid hemihydrate (H 3PO 4·0.5H 2O) crystallization in terms of kinetics and morphology is studied quantitatively. A new method for estimating growth rate is developed by taking the slopes of linearlized lines of transient chord length distribution (CLD) of crystals during the process using an in-line device of Focused Beam Reflectance Monitoring (FBRM). The presence of cations can reduce the nucleation rate of phosphoric acid while anions have less effect. Impurities of Fe 3+, Al 3+, and F - (>50 ppm) can widen the metastable zone to some extent. Adding small amounts of H 2SO 4 (<150 ppm) can enlarge metastable zone, but such effect becomes less after adding more H 2SO 4. The presence of the SO 42- tends to encourage H 3PO 4·0.5H 2O crystal growth in a wide concentration range with the maximum growth rate at 5000 ppm. Addition of Fe 3+ and Al 3+ at low level can increase crystal growth rate until it reaches a maximum at 500, 50, and 100 ppm for F -, Al 3+, and Fe 3+, respectively. Impurities of cations appear to have significant effect on crystal morphology; anions, however, appear not to change crystal shapes much.

Dang, Leping; Wei, Hongyuan; Zhu, Zheng; Wang, Jingkang

2007-09-01

313

Blue luminescence in porous anodic alumina films  

NASA Astrophysics Data System (ADS)

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

Li, Zhaojian; Huang, Kelong

2007-05-01

314

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

PubMed Central

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

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

2015-01-01

315

Optimization of zinc phosphate coating on 7075-T6 aluminum alloy  

NASA Astrophysics Data System (ADS)

A zinc phosphate coating process on 7075-T6 aluminum alloy has been significantly improved through a combined approach of titanium colloid pretreatment, pH level adjustment, fluoride additive and {ZnO}/{H 3PO 4} ratio adjustment. In particular, optimum phosphate coatings were formed in coating baths with a {ZnO}/{H 3PO 4} ratio of 0.205 and 0.256. Coating morphology studied by SEM reveals that the adjustment in the coating procedure produces an improved crystalline coating layer with high coverage and small grain size. For coatings formed in a bath with a ratio of 0.205, the coverage of the crystalline patches on top of the amorphous coating base is almost complete. The chemical composition of the coating layers has been characterized by XPS and SIMS. The crystalline and amorphous coating phases formed in the bath with a ratio of 0.205 were found to have compositions given schematically as Zn x(PO 4) and Zn xAl y(PO 4), respectively. In contrast, neither coating phase formed in the bath with a ratio of 0.256 shows the presence of Al.

Ying, J. F.; Flinn, B. J.; Zhou, M. Y.; Wong, P. C.; Mitchell, K. A. R.; Fostert, T.

1995-12-01

316

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

NASA Astrophysics Data System (ADS)

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

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

2004-11-01

317

A study of oxygen reduction on platinum-dispersed porous carbon electrodes at room and elevated temperatures by using a.c. impedance spectroscopy  

NASA Astrophysics Data System (ADS)

Oxygen reduction on unwetted and pre-wetted platinum-dispersed porous carbon electrodes (Pt/C) is investigated in 1 M H 2SO 4 solution at room temperature by using a.c. impedance spectroscopy in combination with a current-decay transient technique (chronoamperometry). From the appearance of an inductive arc in Nyquist plots from the unwetted Pt/C electrode specimen, it is suggested that oxygen reduction proceeds via formation of an intermediate state. The a.c. impedance spectra are also obtained from the Pt/C electrode in 85% H 3PO 4 solution at 140°C, with and without oxygen and air blowings. In both cases, an inductive arc in the low-frequency range of the Nyquist plots is observed. The change in impedance spectra with pre-wetting treatment of the Pt/C electrode specimen in 1 M H 2SO 4 solution and the alteration of spectra without oxygen and air blowings in 85% H 3PO 4 solution are discussed in terms of the Epelboin model. From the analysis, it is concluded that as depletion of the dissolved oxygen occurs markedly within the narrow pores of the Pt/C electrode, the inductive arc moves towards the capacitive arc in the low-frequency range. The results of current-decay transients strongly suggest the occurrence of depletion of the dissolved oxygen within the narrow pores.

Pyun, Su-Il; Ryu, Young-Gyoon

318

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

NASA Astrophysics Data System (ADS)

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

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

2005-08-01

319

Element composition and mineralogical characterisation of air pollution control residue from UK energy-from-waste facilities.  

PubMed

Air pollution control (APC) residues from energy-from-waste (EfW) are alkaline (corrosive) and contain high concentrations of metals, such as zinc and lead, and soluble salts, such as chlorides and sulphates. The EPA 3050B-extractable concentrations of 66 elements, including critical elements of strategic importance for advanced electronics and energy technologies, were determined in eight APC residues from six UK EfW facilities. The concentrations of Ag (6-15mg/kg) and In (1-13mg/kg), as well as potential pollutants, especially Zn (0.26-0.73wt.%), Pb (0.05-0.2wt.%), As, Cd, Cu, Mo, Sb, Sn and Se were found to be enriched in all APC residues compared to average crustal abundances. Results from a combination of scanning electron microscopy with energy dispersive X-ray spectroscopy and also powder X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy give an exceptionally full understanding of the mineralogy of these residues, which is discussed in the context of other results in the literature. The present work has shown that the bulk of the crystalline phases present in the investigated APC residues include Ca-based phases, such as CaClxOH2-x, CaCO3, Ca(OH)2, CaSO4, and CaO, as well as soluble salts, such as NaCl and KCl. Poorly-crystalline aragonite was identified by FTIR. Sulphur appears to have complex redox speciation, presenting as both anhydrite and hannebachite in some UK EfW APC residues. Hazardous elements (Zn and Pb) were widely associated with soluble Ca- and Cl-bearing phases (e.g. CaClxOH2-x and sylvite), as well as unburnt organic matter and aluminosilicates. Specific metal-bearing minerals were also detected in some samples: e.g., Pb present as cerussite; Zn in gahnite, zincowoodwardite and copper nickel zinc oxide; Cu in tenorite, copper nickel zinc oxide and fedotovite. Aluminium foil pieces were present and abundantly covered by fine phases, particularly in any cracks, probably in the form of Friedel's salt. PMID:25541041

Bogush, Anna; Stegemann, Julia A; Wood, Ian; Roy, Amitava

2015-02-01

320

Alcohol dispersions of calcium hydroxide nanoparticles for stone conservation.  

PubMed

Alcohol dispersions of Ca(OH)2 nanoparticles, the so-called nanolimes, are emerging as an effective conservation material for the consolidation of stone, mortars, and plasters present in old masonry and/or mural paintings. To better understand how this treatment operates, to optimize its performance and broaden its applications, here we study the nano and microstructural characteristics, carbonation behavior, and consolidation efficacy of colloidal alcohol dispersions of Ca(OH)2 nanoparticles produced by both homogeneous (commercial nanolime) and heterogeneous phase synthesis (aged slaked lime and carbide lime putties). We observe that the alcohol not only provides a high colloidal stability to Ca(OH)2 particles, but also affects the kinetics of carbonation and CaCO3 polymorph selection. This is due to the pseudomorphic replacement of Ca(OH)2 particles by calcium alkoxides upon reaction with ethanol or 2-propanol. The extent of this replacement reaction depends on Ca(OH)2 size and time. Hydrolysis of alkoxides speeds up the carbonation process and increases the CaCO3 yield. The higher degree of transformation into calcium alkoxide of both the commercial nanolime and the carbide lime fosters metastable vaterite formation, while calcite precipitation is promoted upon carbonation of the aged slaked lime due its lower reactivity, which limits calcium alkoxide formation. A higher consolidation efficacy in terms of strength gain of treated porous stone is achieved in the latter case, despite the fact that the carbonation is much faster and reaches a higher yield in the former ones. Formation of alkoxides, which has been neglected in previous studies, needs to be considered when applying nanolime treatments. These results show that the use Ca(OH)2 nanoparticle dispersions prepared with either aged slaked lime or carbide lime putties is an economical and effective conservation alternative to commercial nanolimes produced by homogeneous phase synthesis. Ultimately, this study contributes to show that nanotechnology can help saving the built and sculptural heritage. PMID:23919634

Rodriguez-Navarro, Carlos; Suzuki, Amelia; Ruiz-Agudo, Encarnacion

2013-09-10

321

Color removal from dye-containing wastewater by magnesium chloride  

Microsoft Academic Search

Color removal by MgCl2 when treating synthetic waste containing pure dyes was studied. The color removal efficiency of MgCl2\\/Ca(OH)2 was compared with that of Al2(SO4)3, polyaluminum chloride (PAC) and FeSO4\\/Ca(OH)2. The mechanism of color removal by MgCl2 was also investigated. The experimental results show that the color removal efficiency of MgCl2 is related to the type of dye and depends

Bao-Yu Gao; Qin-Yan Yue; Yan Wang; Wei-Zhi Zhou

2007-01-01

322

The effect of oxidation treatment by KClO3/H2SO4 system on intersurface performance of carbon fibers  

NASA Astrophysics Data System (ADS)

The polyacrylonitrile-based (PAN-based) carbon fibers with progressive amounts of the oxidation treatment have been investigated using a number of surface analytical methods. The chemical content and structure of oxidated fibers have been interrogated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM), then compared to the untreated ones. The value of oxygen content increased from 4.71% to 18.84%, meanwhile, the grooves on the surfaces of the carbon fibers were deepened gradually after treatments. The results of dynamic contact angle (DCA) measurements suggest that the increase in carbon fiber surface tension is mainly because of the polar component of surface tension. After treated with increasing amounts of oxidants, the monofilament tensile strength decreased less than 3.1%.

Meng, Linghui; Fan, Dapeng; Zhang, Chunhua; Jiang, Zaixing; Huang, Yudong

2013-03-01

323

Phase diagram studies of the systems KCl-K 3 MoCl 6 and LiCl-K 3 MoCl 6  

Microsoft Academic Search

As part of an investigation of fused salt electroplating of molybdenum coatings] the phase diagrams of the two binary systems, LiCI-K3MoC16 and KCI-K3MoCI6, have been determined. These compounds are the principal constituents of the electrolyte employed in the plating studies which had as one of their goals to minimize thermal damage to the substrate through the use of a \\

Georges J. Kipouros; Donald R. Sadoway

1986-01-01

324

Excretion of NaCl and KCl loads in mosquitoes. 2. Effects of the small molecule Kir channel modulator VU573 and its inactive analog VU342.  

PubMed

The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 ?M) had no effect on the transepithelial secretion of Na(+), K(+), Cl(-), and water. In contrast, 10 ?M VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules were bathed in Na(+)-rich or K(+)-rich Ringer solution. The early stimulation was blocked by bumetanide, suggesting the transient stimulation of Na-K-2Cl cotransport, and the late inhibition of fluid secretion was consistent with the known block of AeKir1, an Aedes inward rectifier K(+) channel, by VU573. VU342 and VU573 at a hemolymph concentration of about 11 ?M had no effect on the diuresis triggered by hemolymph Na(+) or K(+) loads. VU342 at a hemolymph concentration of 420 ?M had no effect on the diuresis elicited by hemolymph Na(+) or K(+) loads. In contrast, the same concentration of VU573 significantly diminished the Na(+) diuresis by inhibiting the urinary excretion of Na(+), Cl(-), and water. In K(+)-loaded mosquitoes, 420 ?M VU573 significantly diminished the K(+) diuresis by inhibiting the urinary excretion of K(+), Na(+), Cl(-), and water. We conclude that 1) the effects of VU573 observed in isolated Malpighian tubules are overwhelmed in vivo by the diuresis triggered with the coinjection of Na(+) and K(+) loads, and 2) at a hemolymph concentration of 420 ?M VU573 affects Kir channels systemically, including those that might be involved in the release of diuretic hormones. PMID:25056106

Rouhier, Matthew F; Hine, Rebecca M; Park, Seokhwan Terry; Raphemot, Rene; Denton, Jerod; Piermarini, Peter M; Beyenbach, Klaus W

2014-10-01

325

Acid and alkali doped PBI electrolyte in electrochemical system  

NASA Astrophysics Data System (ADS)

In this work the conductivity of blank PBI membrane, acid doped PBI and alkaline doped PBI was systematically studied. A new methodology for sorption kinetics study in electrolyte solution has been established by monitoring the conductivity change during the sorption process. The model of the doping process and mechanism of conductivity are proposed. The performance of PBI (doped under optimum conditions) in fuel cell as PEM was evaluated. The experimental results show that the blank PBI in acid solution is an ionic insulator. It clarified the long time confusion in this area. The acid doped PBI membrane is an ionic conductor. The conductivity increases with the concentration of the acid solution. In high concentration acid solution, the conductivity increases with the type of acid in the order: H2SO 4 > H3PO4 > HClO4 > HNO3 > HCl. The kinetics of the doping process was studied, by a continuous method. The ionic conductivity mechanism was established. The PBI membranes doped with H2SO4 and H3PO4 exhibit better performance than NafionRTM. The doped FBI has more resistance to CO poison. 3% CO in H2 has little effect on the H3PO 4 doped PBI membrane at 185°C. The conductivity of the alkali doped PBI membrane changes with the concentration of the alkaline solution and the type of the alkalis. The conductivity has a maximum in KOH and NaOH solution. The maximum conductivity in KOH is higher than in NaOH and LiOH. It is about 5 times of that of NafionRTM in alkaline solution. The two-step sorption process in alkaline solution was observed. The first step is the permeation process of the alkalis in the PBI membrane. The permeation is the results of diffusion and interaction. It is concluded that the permeation process is controlled by the rate of interaction between the alkali and PBI molecule. The second step is the relaxation process in the membrane. This step contributes more to the conductivity for the membrane than the first step. The ionic conductivity mechanism was established. In solution the cations and OH- all participate in the transport of current. It is the OH- that breaks the bonds between PBI molecules and enables the cations pass through the membrane. The performance of alkali doped PBI (doped under optimum conditions) in fuel cell as PEM is as good as NafionRTM.

Xing, Baozhong

326

Hydrogeochemical contrasts between low and high arsenic groundwater and its implications for arsenic mobilization in shallow aquifers of the northern Yinchuan Basin, P.R. China  

NASA Astrophysics Data System (ADS)

Little is known about hydrogeochemical contrasts between low and high As groundwaters and their connection to As mobilization in the Yinchuan Basin. Investigations were carried out to evaluate As distribution and geochemical processes for As mobilization in three regions, including piedmont proluvial fans (PA), dry farmland (DF) and paddy farmland (PF). Ninety-two groundwater samples, 4 surface water samples, and 66 sediments samples were collected and analyzed for chemical and isotopic components. Results show that low As groundwater is generally found in PA. However, high As concentrations (up to 105 ?g L-1) are mainly observed in groundwaters from DF and PF, which are associated with reducing conditions. High As groundwater is characterized by high concentrations of NH4+, dissolved Mn, dissolved Fe and Fe(II), and low concentrations of NO3- and SO42-. The intensive irrigation in PF recharges the aquifers by vertical infiltration of the diverted Yellow River water, and leads to the higher redox potentials and the lower dissolved As in comparison with those in DF. Environmental isotopes (?18O and ?D) show that evaporation due to the intensive irrigation plays a minor role in As enrichment. The positive correlation between As and dissolved Fe suggests that groundwater As would result from the reductive dissolution of Fe oxides. Besides, dissolved P may be involved in competing with As for binding sites on Fe oxide minerals. Sediment As ranges between 3.94 and 75.2 mg kg-1. HCl-leached As accounts for 60% of total As in the sediments, while H3PO4-leached As accounts for 5%. Depth-matched samples show a good correlation between dissolved As and H3PO4-leached As in sediments. Arsenic distribution coefficient (Kd), calculated from H3PO4-leached As and dissolved As, ranges between 5.08 and 17.3 cm3 g-1, which generally depends on groundwater redox potentials. In reducing conditions, low values are found with As being preferentially partitioned into groundwater.

Guo, Qi; Guo, Huaming; Yang, Yuance; Han, Shuangbao; Zhang, Fucun

2014-10-01

327

SUMMARY REPORT: SULFUR OXIDES CONTROL TECHNOLOGY SERIES: FLUE GAS DESULFURIZATION - SPRAY DRYER PROCESS  

EPA Science Inventory

Described spray dryer flue gas desulfurization (FGD), which is a throwaway process in which sulfur dioxide (SO2) is removed from flue gas by an atomized lime slurry [Ca(OH)2]. he hot flue gas dries the droplets to form a dry waste product, while the absorbent reacts with sulfur d...

328

FUNDAMENTAL STUDIES OF DRY INJECTION OF CALCIUM-BASED SORBENTS FOR S02 CONTROL IN UTILITY BOILERS  

EPA Science Inventory

The report describes research to determine the mechanisms which limit the extent of reaction between SO2 and calcium-based sorbents (CaCO3 and Ca(OH)2) by measuring the in situ physical structure and reactivity of sorbent injected into a combustion environment for residence times...

329

Zentrum f ur Technomathematik Fachbereich 3 --Mathematik und Informatik  

E-print Network

places. But using such fine grid everywhere, the computation will get very slow, especially two and three everywhere, because slowly varying concentration fields can easily approximated a relatively coarse mesh carbonation concrete, involving the concentrations 1 c CO 2 and liquid phases, c Ca(OH) 2 water, and total

Bremen, Universität

330

Sequential precipitation of a new goethite-calcite nanocomposite and its1 possible application in the removal of toxic ions from polluted water2  

E-print Network

1 Sequential precipitation of a new goethite-calcite nanocomposite and its1 possible application for a goethite-calcite2 nanocomposite. This synthesis is summarized by three sequential precipitation reactionsNaOH + CaCl2 Ca(OH)2 + 2NaCl) and; (3) sub-micrometric calcite6 precipitation by injection of CO2

Paris-Sud XI, Université de

331

Synthesis of a Se0 /calcite composite using hydrothermal1  

E-print Network

1 Synthesis of a Se0 /calcite composite using hydrothermal1 carbonation of Ca(OH)2 coupled )/calcite composite. Under O2-poor conditions, the composite was mainly characterized6 by red spherical selenium nanoparticles "non crystalline elemental selenium" (calcite matrix

Paris-Sud XI, Université de

332

Dentinal tubule disinfection with 2% chlorhexidine, garlic extract, and calcium hydroxide against Enterococcus faecalis by using real-time polymerase chain reaction: In vitro study  

PubMed Central

Aim: To compare the efficacy of garlic extract with 2% chlorhexidine (CHX) and calcium hydroxide Ca(OH)2 in disinfection of dentinal tubules contaminated with Enterococcus faecalis by using real-time polymerase chain reaction (PCR). Materials and Methods: Agar diffusion test was done to evaluate the minimum inhibitory concentration of garlic extract against E. faecalis. Forty human extracted mandibular premolar teeth were selected for this study, access cavity was prepared and cleaning and shaping was done. Middle third of the root was cut using a rotary diamond disc. The teeth specimens were inoculated with E. faecalis for 21 days. Specimens were divided into four groups---Group 1: 2% CHX, Group 2: Garlic extract, Group 3: Ca(OH)2, and Group 4: Saline (negative control). The intracanal medicaments were packed inside the tooth specimens and incubated for 5 days. The dentinal chips were collected at 400 ?m depth using a Gates-Glidden drill, following which DNA isolation was done. The specimens were analyzed using real-time PCR. The results were then statistically analyzed using one-way analysis of variance, followed by post hoc Tukey's honestly significant difference (HSD) multiple comparison of means. Results: Threshold cycle (Ct) values of 2% CHX was found to be 32.4, garlic extract to be 27.5, and Ca(OH)2 to be 25.6. Conclusion: A total of 2% CHX showed the maximum efficacy against E. faecalis, followed by garlic extract and Ca(OH)2. PMID:23833449

Eswar, Kandaswamy; Venkateshbabu, Nagendrababu; Rajeswari, Kalaiselvam; Kandaswamy, Deivanayagam

2013-01-01

333

ACTIVATION AND REACTIVITY OF NOVEL CALCIUM-BASED SORBENTS FOR DRY SO2 CONTROL IN BOILERS  

EPA Science Inventory

Chemically modified calcium hydroxide (Ca(OH)2) sorbents developed in the U.S. Environmental Protection Agency's Air and Energy Engineering Research Laboratory (AEERL) for sulfur dioxide (SO2) control in utility boilers were tested in an electrically heated, bench-scale isotherma...

334

Calcium hydroxide pretreatment of biomass  

E-print Network

rations. Darwish and Galal (1975) used maize cobs treated with 1. 5% Ca(OH)2 in a milk production ration and found no significant change in milk output. Felix er al. (1990) evaluated the effects of ensiling and treating soya-bean straw with NaOH, Ca...

Nagwani, Murlidhar

1992-01-01

335

Journal of Crystal Growth 310 (2008) 29462953 Textural properties of synthetic nano-calcite produced by hydrothermal  

E-print Network

carbonation of calcium hydroxide (Ca(OH)2) at high pressure of CO2 (initial PCO2 ¼ 55 bar) and moderate kg/m3 h) and high purity of product (about 96%). However, the various initial physicochemicalJournal of Crystal Growth 310 (2008) 2946­2953 Textural properties of synthetic nano

Montes-Hernandez, German

336

REACTION MECHANISMS OF DRY CA-BASED SORBENTS WITH GASEOUS HCL  

EPA Science Inventory

The paper discusses an investigation of the mechanisms of HCl reaction with dry Ca(OH)2 or CaO sorbents in flue gas cleaning applications using differential scanning calorimetry (DSC), thermogravimetry (TGA), and X-ray diffraction (XRD). hort-time differential reactor (STDR) was ...

337

HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 1. THEORETICAL SULFATION MODEL  

EPA Science Inventory

A mathematical model for the sulfation of CaO is developed around the overlapping grain concept. The potential influence of high mass-transfer rates from simultaneous calcination of CaCO3 or Ca(OH)2 is incorporated in the mass-transfer coefficient for SO2 diffusion to the partic...

338

CALCINATION AND SINTERING MODELS FOR APPLICATION TO HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM-BASED SORBENTS  

EPA Science Inventory

To simulate the staged availability of transient high surface area CaO observed in high-temperature flow-reactor data, the rate of calcination of CaCO3 or Ca(OH)2 is described by an empirical modification of the shrinking-core model. The physical model depicts particle decomposi...

339

REACTION MECHANISMS OF DRY CA-BASED SORBENTS WITH GASEOUS HCL  

EPA Science Inventory

The mechanisms of HC1 reaction with dry Ca(OH)2 or CaO sorbents in flue gas cleaning applications were investigated by differential scanning calorimetry (DSC), thermogravimetry, and X-ray diffraction. A short-time differential reactor (STDR) was used to contact 1000 ...

340

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

EPA Science Inventory

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

341

INVESTIGATION OF PRODUCT-LAYER DIFFUSIVITY FOR CAO SULFATION  

EPA Science Inventory

The paper gives results of comparisons of the sulfation rates of CaO prepared from Ca(OH)2 and CaCO3, using six types of each precursor derived from the same natural limestones. The particles were small enough to eliminate all transport resistances except diffusion through the Ca...

342

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

343

HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 2. EXPERIMENTAL DATA AND THEORETICAL MODEL PREDICTIONS  

EPA Science Inventory

The fundamental processes for injection of CaCO3 and Ca(OH)2 for the removal of SO2 from combustion gases of coal-fired boilers are analyzed on the basis of experimental data and a comprehensive theoretical model. Sulfation data were obtained in a 30-kW isothermal gas-particle t...

344

EFFECT OF RELATIVE HUMIDITY AND ADDITIVES ON THE REACTION OF SULFUR DIOXIDE WITH CALCIUM HYDROXIDE  

EPA Science Inventory

The paper gives results of a study of the reaction of SO2 with Ca(OH)2 at conditions similar to those of commercial-scale bag filters: 19-74 percent relative humidity (RH), 30.4-95 C, and 300-4000 ppm SO2. The study was carried out in a bench-scale reactor with powder reagent Ca(...

345

Interactive Effects of Soil ph, Halosulfuron Rate, and Application Method on Carryover to Turnip Green and Cabbage.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Field studies were conducted in 2006 and 2007 to evaluate the tolerance of autumn-planted cabbage and turnip green to halosulfuron applied the previous spring to cantaloupe. Main plots were three levels of soil pH; maintained at a natural pH level, pH raised with Ca(OH)2, and pH lowered with Al2(SO...

346

Volatile fatty acid fermentation of lime-treated bagasse by rumen microorganisms  

E-print Network

to increase the digestibility of the cell wall carbohydrates. The treatment conditions were: Ca(OH)2 loading = 10 g/100 g dry bagasse, water loading = 8.5 g/g dry bagasse, temperature 100'C, and treatment time = 1 hour. Compared to untreated bagasse...

Lee, Chang-Ming

2012-06-07

347

THE CHARACTERIZATION OF A SOLID SORBENT WITH CRYSTALLITE SIZE AND STRAIN DATA FROM X-RAY DIFFRACTION LINE BROADENING  

EPA Science Inventory

The paper gives results of the characterization of a solid sorbent with crystallite size and strain data from x-ray diffraction line broadening, as part of an EPA investigation of the injection of dry Ca(OH)2 into coal-fired electric power plant burners for the control of SO2 emi...

348

FURNACE SURBENT REACTIVITY TESTING FOR CONTROL OF SO2 EMISSIONS FROM ILLINOIS COALS  

EPA Science Inventory

Research was undertaken to evaluate the potential of furnai sorbent injection (FSI) for sulf dioxide (S02) emission controlcoal-fired boilers utilizing coals indigenous to Illinois. Tests were run using four coals from the Illinois Basin and six calcium hydroxide [Ca(OH)2], sorbe...

349

FURNACE SORBENT REACTIVITY TESTING FOR CONTROL OF SO2 EMISSIONS FROM ILLINOIS COALS  

EPA Science Inventory

Research was undertaken to evaluate the potential of furnai sorbent injection (FSI) for sulf dioxide (S02) emission controlcoal-fired boilers utilizing coals indigenous to Illinois. Tests were run using four coals from the Illinois Basin and six calcium hydroxide [Ca(OH)2], sorbe...

350

LIGNOSULFONATE-MODIFIED CALCIUM HYDROXIDE FOR SULFUR DIOXIDE CONTROL  

EPA Science Inventory

The article discusses the use of lignosulfonate-modified calcium hydroxide Ca(OH)2 for sulfur dioxide (SO2) control. The limestone injection multistage burner (LIMB) process is currently being developed at the U.S. EPA as a low cost retrofittable technology for controlling oxides...

351

STRUCTURAL CHANGES IN SURFACTANT-MODIFIED SORBENTS DURING FURNACE INJECTION  

EPA Science Inventory

A calcium hydroxide [Ca(OH)2] sorbent modified by the addition of calcium lignosulfonate has recently been developed for use in the Environmental Protection Agency's limestone injection multistage burner process. The increased reactivity with sulfur dioxide (SO2) displayed by thi...

352

ENHANCEMENT OF REACTIVITY IN SURFACTANT-MODIFIED SORBENTS FOR SULFUR DIOXIDE CONTROL  

EPA Science Inventory

Injection of calcium-based sorbents into the postflame zone of utility boilers is capable of achieving sulfur dioxide (SO2) captures of 50-60% at a stoichiometry of 2. Calcium hydroxide [Ca(OH)2] appears to be the most effective commercially available sorbent. Recent attempts to ...

353

ENHANCEMENT OF REACTIVITY IN SURFACTANT-MODIFIED SORBENTS FOR SULFUR DIOXIDE CONTROL  

EPA Science Inventory

The paper discusses the enhancement of reactivity in surfactant-modified sorbents for S02 control. Injecting calcium-based sorbents into the post-flame zone of utility boilers can achieve S02 captures of 50-60% at a stoichiometry of 2. Calcium hydroxide-- Ca(OH)2--appears to be t...

354

SOX OUT ON A LIMB (LIMESTONE INJECTION MULTISTAGE BURNER)  

EPA Science Inventory

The paper describes the most recent results from the Limestone Injection Multistage Burner (LIMB) program, covering results from the wall-fired demonstration. Tests were conducted to determine the efficacy of commercial calcium hydroxide (Ca(OH)2) and of calcium-lignosulfonate-mo...

355

Chemical Reduction of PCE by Zero Valent Iron Colloids Batch and Column Experiments  

E-print Network

of degradation potential of nZVI particles in column tests: experimental simulation of plume vs. source/l · Significant increase of pH after Ca(OH)2 injection · nZVI-reinjection induced recovery of PCE-degradation of the art for plume treatment · Injectable nano-scaled zero valent iron particles (nZVI) have potential

Cirpka, Olaf Arie

356

Performances of toluene removal by activated carbon derived from durian shell.  

PubMed

In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model. PMID:20884200

Tham, Y J; Latif, Puziah Abdul; Abdullah, A M; Shamala-Devi, A; Taufiq-Yap, Y H

2011-01-01

357

Influence of activated carbon upon the photocatalytic degradation of methylene blue under UV-vis irradiation.  

PubMed

Photodegradation of methylene blue (MB) was studied on TiO2 in the presence of activated carbon (AC) prepared from the sawdust of a soft wood by physical activation under CO2 flow, by pyrolysis under N2 flow, and by chemical activation with ZnCl2 and H3PO4 under N2 flow. MB photodegradation was performed under UV and UV-visible irradiation to verify the scaling-up of the present TiO2-AC binary materials. It was verified that oxygenated surface groups on carbon were intrinsically photoactive, and a synergy effect between both solids has been estimated from the first-order apparent rate constants in the photodegradation of MB. This effect enhances the photoactivity of TiO2 up to a factor of about 9 under visible irradiation, and it was associated to the surface properties of AC. PMID:24788930

Matos, Juan; Montaña, Ricmary; Rivero, Eliram

2015-01-01

358

Mechanism of the protonation of azulenes in aqueous solutions of acids  

NASA Astrophysics Data System (ADS)

In aqueous solutions of strong acids (H2SO4, H3PO4, and HCl) containing azulene, the fast reversible protonation of azulene is accompanied by the slow formation of a disperse dark violet dye insoluble in acids, alcohol, and heptane. On the basis of the kinetic specifics of this reaction and the nonlinear (nearly reciprocal quadratic) dependence of the concentrations ratio of their cationic and neutral forms on the Hammett acidity function known for azulene and 14 of its derivatives, azulene is shown not to be a Hammett base. A mechanism for the reversible reactions of the azulenium cation is proposed that considers supramolecular dimers to be the basic state of azulene and its derivatives. The scheme includes reactions of the unstable intermediate ? complexes formed from the dimers and hydrated hydrogen cations; the complexes quickly dissociate in the opposite direction and react with the hydrated protons to yield azulenium cations and unstable molecules that induce polymerization of the dimers.

Mikheev, Yu. A.; Guseva, L. N.; Ershov, Yu. A.

2013-10-01

359

Characterization of wide-band-gap semiconductors (GaN, SiC) by defect-selective etching and complementary methods  

NASA Astrophysics Data System (ADS)

Two defect-selective etching approaches used for revealing and analysis of defects in wide-band-gap semiconductors (GaN, SiC) are described in detail: (i) orthodox etching in molten salts (KOH, NaOH) and hot acids (H 2SO 4,H 3PO 4) and (ii) electroless photo-etching (photoelectrochemical or PEC) in aqueous solutions of KOH. Characteristic features of these two techniques, their reliability and limitation in revealing different types of defects (dislocations, stacking faults, micro-defects and electrically active chemical non-homogeneities) will be discussed. Examples of the use of both etching approaches to reveal defects in bulk and epitaxial layers of different crystallographic orientation are given. Numerous references to previous work on calibration of the etch features by means of TEM, X-ray diffraction, Raman and PL methods are cited.

Weyher, J. L.

2006-10-01

360

Development of value-added products from alumina industry mineral wastes using low-temperature-setting phosphate ceramics  

SciTech Connect

A room-temperature process for stabilizing mineral waste streams has been developed, based on acid-base reaction between MgO and H3PO4 or acid phosphate solution. The resulting waste form sets into a hard ceramic in a few hours. In this way, various alumina industry wastes, such as red mud and treated potliner waste, can be solidified into ceramics which can be used as structural materials in waste management and construction industry. Red mud ceramics made by this process were low-porosity materials ({approx}2 vol%) with a compression strength equal to portland cement concrete (4944 psi). Bonding mechanism appears to be result of reactions of boehmite, goethite, and bayerite with the acid solution, and also encapsulation of red mud particles in Mg phosphate matrix. Possible applications include liners for ponds and thickned tailings disposal, dikes for waste ponds, and grouts. Compatability problems arising at the interface of the liner and the waste are avoided.

Wagh, A.S.; Jeong, Seung-Young; Singh, D.

1996-01-01

361

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

PubMed

A novel automatic stepwise injection headspace single-drop micro-extraction system is proposed as a versatile approach for automated determination of volatile compounds. The system application is demonstrated for ammonia determination in concrete samples. An ammonia gas was produced from ammonium ions and extracted on-line into 5 ?L 0.1M H3PO4 to eliminate the interference effect of concrete species on the ammonia stepwise injection spectrophotometric determination. The linear range was 0.1-1 mg kg(-1) with LOD 30 µg kg(-1). The sample throughput was 4 h(-1). This system has been successfully applied for the determination of ammonia in concretes. PMID:25435223

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

2015-02-01

362

Effects of ultrasonic fields in the phosphoric acid process  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

363

A sensitive enzyme-catalytic nanogold-resonance scattering spectral assay for alkaline phosphate.  

PubMed

In pH 8.9 Tris-HCl buffer solutions, alkaline phosphatase (ALP) catalyzed the hydrolysis of ascorbic acid 2-phosphate (AAP) substrate to form ascorbic acid. Then H(3)PO(4) was added to stop the enzymatic reaction and HAuCl(4) was used to react with ascorbic acid to generate gold nanoparticles that exhibited a resonance scattering (RS) peak at 600 nm. Under the selected conditions, when the activity of ALP increased, the formed ascorbic acid and gold nanoparticles also increased. Thus, the RS intensity at 600 nm enhanced linearly. The linear range was 0.06-22 U/L, with a detection limit of 0.03 U/L. The ALP in serum was analyzed, and the results were in agreement with those of the fluorescence method. PMID:22113359

Jiang, Zhiliang; Wu, Meng; Liu, Gaosan; Liang, Aihui

2012-06-01

364

Anodized titania: Processing and characterization to improve cell-materials interactions for load bearing implants  

NASA Astrophysics Data System (ADS)

The objective of this study is to investigate in vitro cell-materials interactions using human osteoblast cells on anodized titanium. Titanium is a bioinert material and, therefore, gets encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. In this work, bioactive nonporous and nanoporous TiO2 layers were grown on commercially pure titanium substrate by anodization process using different electrolyte solutions namely (1) H3PO 4, (2) HF and (3) H2SO4, (4) aqueous solution of citric acid, sodium fluoride and sulfuric acid. The first three electrolytes produced bioactive TiO2 films with a nonporous structure showing three distinctive surface morphologies. Nanoporous morphology was obtained on Ti-surfaces from the fourth electrolyte at 20V for 4h. Cross-sectional view of the nanoporous surface reveals titania nanotubes of length 600 nm. It was found that increasing anodization time initially increased the height of the nanotubes while maintaining the tubular array structure, but beyond 4h, growth of nanotubes decreased with a collapsed array structure. Human osteoblast (HOB) cell attachment and growth behavior were studied using an osteoprecursor cell line (OPC 1) for 3, 7 and 11 days. Colonization of the cells was noticed with distinctive cell-to-cell attachment on HF anodized surfaces. TiO2 layer grown in H2SO4 electrolyte did not show significant cell growth on the surface, and some cell death was also noticed. Good cellular adherence with extracellular matrix extensions in between the cells was noticed for samples anodized with H3PO 4 electrolyte and nanotube surface. Cell proliferation was excellent on anodized nanotube surfaces. An abundant amount of extracellular matrix (ECM) between the neighboring cells was also noticed on nanotube surfaces with filopodia extensions coming out from cells to grasp the nanoporous surface for anchorage. To better understand and compare cell-materials interactions, anodized nanoporous sample surfaces were etched with different patterns. Preferential cell attachment was noticed on nanotube surfaces compared to no cells on etched patterned surface. Cell adhesions and differentiation were more pronounced with vinculin protein and alkaline phosphatase, respectively, on anodized surfaces. MTT assays showed increase in living cell density and higher proliferation on H3PO4, HF and nanotube surfaces. When anodized surfaces were compared for cell materials interaction, it was noticed that each of the surfaces has different surface properties that led to variations in cell-materials interactions. It was clear that rough surface morphology, high surface energy, and low value of the contact angles were important factors for better cell materials interaction. Mineralization study was done in simulated body fluid (SBF) with ion concentration nearly equal to human blood plasma to further understand biomimetic apatite deposition behavior. Similar to cell-materials interaction, variation in mineral deposition behavior was also noticed for films grown with different electrolytes. These results clearly show that nonporous titania in H3PO4, HF electrolytes and nanotubes can significantly increase biocompatibility of Ti implants, which has the potential to reduce the healing time and increase in vivo lifetime for these implants.

Das, Kakoli

365

Palladation of diimidazolium salts at the C4 position: access to remarkably electron-rich palladium(II) centers.  

PubMed

Palladation of C2-protected diimidazolium salts with Pd(OAc)2 afforded complexes comprising C4-bound N-heterocyclic dicarbene ligands. The reactivity of these complexes towards Lewis acids (AgBF4, AgOAc) and Brønsted acids (H2SO4, H3PO4, HOAc) revealed that abnormal C4 bonding of the carbenes markedly increases the nucleophilicity of the coordinated palladium center as compared to C2 bonding. Despite its formal +2 charge, the palladium center in these complexes is best described as a Lewis base. The abnormal carbene bonding mode induces new reaction patterns such as the formation of a Pd-Ag adduct. Based on metallation studies including the palladation of a dissymmetric diimidazolium salt, a rationale for the selective activation of the C4-H bond in the diimidazolium precursor salts is proposed. PMID:18985257

Heckenroth, Marion; Kluser, Evelyne; Neels, Antonia; Albrecht, Martin

2008-11-28

366

:Eu Nanophosphors for a Near-UV LED  

NASA Astrophysics Data System (ADS)

The luminescence of LaPO4:Eu phosphors was improved by coprecipitation with phosphate from different sources and with anionic surfactants. The effects of the method of synthesis on the characteristics of the phosphors were investigated. When H3PO4 was used as the source of phosphate, strong absorption of the charge transfer band (CTB) was observed. A red shift of the CTB absorption was observed when (NH4)2HPO4 and Na5P3O10 were used as sources of phosphate. Phosphors with high crystallographic symmetry of Eu3+ in the lattice were synthesized when (NH4)2HPO4 was used. The optimum crystallinity and the maximum photoluminescence (PL) intensity were obtained when the phosphor surface was modified with 1 mol.% (NaPO3)6 and 3 mol.% sodium dodecyl sulfate (SDS) surfactant, with PL intensity being increased by 10% and 7%, respectively.

Yang, Su-Hua; Yang, Chih-Ka; Yan, Jia-Hung; Lin, Che-Min

2014-09-01

367

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

NASA Astrophysics Data System (ADS)

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

Malekfar, R.; Abbasi, B.

2005-09-01

368

GaN-based LEDs with air voids prepared by laser scribing and chemical etching  

NASA Astrophysics Data System (ADS)

The authors report the formation of air-voids at GaN/cone-shaped-patterned-sapphire-substrate interface by laser scribing and lateral etching with one-step growth. With 5 and 20 min lateral etching, it was found that pyramid-like airvoid was formed with an average height of 0.98 and 1.9 ?m, respectively, on top of each corn of the substrate. It was also found that we can enhance output power of GaN-based light-emitting diodes by 6.6 and 11.5%, respectively, by immersing the wafer in a mixture of H3PO4 and H2SO4 solution at 220°C for 5 and 20 min, respectively.

Chang, S. J.

2012-03-01

369

Valorization of phosphogypsum as hydraulic binder.  

PubMed

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

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

2008-12-30

370

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

PubMed

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

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

2014-11-01

371

The solubility of ozone in aqueous solutions of sulfuric, phosphoric, and perchloric acids  

NASA Astrophysics Data System (ADS)

The solubility of ozone in pure water and aqueous solutions of sulfuric, phosphoric, and perchloric acids was determined at 20°C. An increase in the concentration of H3PO4 and HClO4 (to 14.8 and 9.5 M, respectively) caused a monotonic decrease in the solubility of ozone. The solubility of ozone in sulfuric acid was minimum at a 12 M concentration; the solubility then increased and, in 17.9 M H2SO4, reached almost the same value as in pure water. The ratio between the concentrations of O3 in solution and the gas phase was 0.276 in pure water, 0.122 in 12 M H2SO4, and 0.265 in 17.9 M H2SO4. The results obtained are compared with the available literature data.

Levanov, A. V.; Kuskov, I. V.; Antipenko, E. E.; Lunin, V. V.

2008-07-01

372

Development of samarium [32P] phosphate colloid for radiosynoviorthesis applications: preparation, biological and preliminary clinical studies experience.  

PubMed

A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl3 carrier with carrier added [32P]H3PO4 in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for the usage period of 14 days, as assessed by paper chromatography. Ninety percent of colloid particles were in the size of 1-10 microm as evident from the laser diffraction particle size analysis, ideally suitable for the intended end use. Animal studies revealed complete retention of the radio colloid in the rabbit knee joint. The results of clinical trials in humans are satisfactory and encouraging, satisfactory retention of the colloid in the knee joint and negligible leakage into the systemic circulation. PMID:17764961

Prabhakar, G; Sachdev, Satbir S; Umamaheswari, S; Sivaprasad, N; Bhatia, Manohar H; Chaudhari, Pradip R; Solav, Srikant V

2007-12-01

373

Multi-silicon ridge nanofabrication by repeated edge lithography.  

PubMed

We present a multi-Si nanoridge fabrication scheme and its application in nanoimprint lithography (NIL). Triple Si nanoridges approximately 120 nm high and 40 nm wide separated by 40 nm spacing are fabricated and successfully applied as a stamp in nanoimprint lithography. The fabrication scheme, using a full-wet etching procedure in combination with repeated edge lithography, consists of hot H(3)PO(4) acid SiN(x) retraction etching, 20% KOH Si etching, 50% HF SiN(x) retraction etching and LOCal Oxidation of Silicon (LOCOS). Si nanoridges with smooth vertical sidewalls are fabricated by using Si 110 substrates and KOH etching. The presented technology utilizes a conventional photolithography technique, and the fabrication of multi-Si nanoridges on a full wafer scale has been demonstrated. PMID:19597243

Zhao, Yiping; Berenschot, Erwin; Jansen, Henri; Tas, Niels; Huskens, Jurriaan; Elwenspoek, Miko

2009-08-01

374

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

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

375

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

PubMed

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

Kasikowski, T; Buczkowski, R; Lemanowska, E

2004-12-01

376

CO2 Adsorption on Activated Carbon Honeycomb-Monoliths: A Comparison of Langmuir and Tóth Models  

PubMed Central

Activated carbon honeycomb-monoliths with different textural properties were prepared by chemical activation of African palm shells with H3PO4, ZnCl2 and CaCl2 aqueous solutions of various concentrations. The adsorbents obtained were characterized by N2 adsorption at 77 K, and their carbon dioxide adsorption capacities were measured at 273 K and 1 Bar in volumetric adsorption equipment. The experimental adsorption isotherms were fitted to Langmuir and Tóth models, and a better fit was observed to Tóth equation with a correlation coefficient of 0.999. The maximum experimental values for adsorption capacity at the highest pressure (2.627–5.756 mmol·g?1) are between the calculated data in the two models. PMID:22942710

Vargas, Diana P.; Giraldo, Liliana; Moreno-Piraján, Juan C.

2012-01-01

377

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

PubMed

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

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

2014-11-01

378

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

PubMed

Organic waste such as manure is an important resource for biogas production. The biodegradability of manures is however limited because of the recalcitrant nature of the biofibers it contains. To increase the biogas potential of the biofibers in digested manure, we investigated physical treatment (milling), chemical treatment (CaO), biological treatment (enzymatic and partial aerobic microbial conversion), steam treatment with catalyst (H(3)PO(4) or NaOH) and combination of biological and steam treatments (biofibers steam-treated with catalyst were treated with laccase enzyme). We obtained the highest methane yield increase through the chemical treatment that resulted in 66% higher methane production compared to untreated biofibers. The combination of steam treatment with NaOH and subsequent enzymatic treatment increased the methane yield by 34%. To choose the optimal treatment, the energy requirements relative to the energy gain as extra biogas production have to be taken into account, as well as the costs of chemicals or enzymes. PMID:20638274

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

2010-11-01

379

Preparation and properties of a coated slow-release and water-retention biuret phosphoramide fertilizer with superabsorbent.  

PubMed

In this investigation, a novel water-insoluble slow-release fertilizer, biuret polyphosphoramide (BPAM), was formulated and synthesized from urea, phosphoric acid (H(3)PO(4)), and ferric oxide (Fe(2)O(3)). The structure of BPAM was characterized by Fourier transform infrared (FTIR) spectroscopy. Subsequently, a coated slow-release BPAM fertilizer with superabsorbent was prepared by ionic cross-linked carboxymethylchitosan (the core), acrylic acid, acrylamide, and active carbon (the coating). The variable influences on the water absorbency were investigated and optimized. Component analysis results showed that the coated slow-release BPAM contained 5.66% nitrogen and 11.7% phosphorus. The property of water retention, the behavior of slow release of phosphorus, and the capacity of adsorption of cations were evaluated, and the results revealed that the product not only had good slow-release property and excellent water retention capacity but also higher adsorption capacities of cations in saline soil. PMID:21155599

Jin, Shuping; Yue, Guoren; Feng, Lei; Han, Yuqi; Yu, Xinghai; Zhang, Zenghu

2011-01-12

380

[Simultaneous determination of three homoisoflavonoids in Ophiopogon japonicus by HPLC].  

PubMed

Three homoisoflavonoids, 6-aldehydo-3-ophiopogonanone A, methyl ophiopogonanone A and ophiopogonanone A from Ophiopogon japonicus were analyzed simultaneously by HPLC with acetonitrile-water containing 0.5% H3 PO4 (58:42) as the mobile phase, and the detection wavelength was set at 296 nm (0-14 min) and 275 nm (14-22 min). The mean recoveries of three homoisoflavonoids were 99.41%-99.86% (RSD 0.82%-1.05%). The linear response ranges of. 6-aldehydo-3-ophiopogonanone A, methyl ophiopogonanone A and ophiopogonanone A were 0.165-0.990 microg (r = 0.999 9), 0.153-0.918 microg (r = 0.999 9), and 0.270-1.620 microg (r = 0.999 9), respectively. This method was certified to be accurate and reliable and can be used for quality control of O. japonicus. PMID:22741465

Zeng, Pintao; Zhou, Hui; Zheng, Yimin; Xu, Xiuying; Fu, Shanquan

2012-01-01

381

Wet etching and chemical polishing of InAs/GaSb superlattice photodiodes  

NASA Astrophysics Data System (ADS)

In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H3PO4), citric acid (C6H8O7) and H2O2, followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current-voltage measurements. The zero-bias resistance area product R0A above 4 × 105 ? cm2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air.

Chaghi, R.; Cervera, C.; Aït-Kaci, H.; Grech, P.; Rodriguez, J. B.; Christol, P.

2009-06-01

382

Temperature dependence of the electrode kinetics of oxygen reduction at the platinum/Nafion interface - A microelectrode investigation  

NASA Technical Reports Server (NTRS)

Results of a study of the temperature dependence of the oxygen reduction kinetics at the Pt/Nafion interface are presented. This study was carried out in the temperature range of 30-80 C and at 5 atm of oxygen pressure. The results showed a linear increase of the Tafel slope with temperature in the low current density region, but the Tafel slope was found to be independent of temperature in the high current density region. The values of the activation energy for oxygen reduction at the platinum/Nafion interface are nearly the same as those obtained at the platinum/trifluoromethane sulfonic acid interface but less than values obtained at the Pt/H3PO4 and Pt/HClO4 interfaces. The diffusion coefficient of oxygen in Nafion increases with temperature while its solubility decreases with temperature. These temperatures also depend on the water content of the membrane.

Parthasarathy, Arvind; Srinivasan, Supramanian; Appleby, A. J.; Martin, Charles R.

1992-01-01

383

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

NASA Astrophysics Data System (ADS)

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

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

2006-08-01

384

Fabrication of Monolithic Sapphire Membranes for High T(sub c) Bolometer Array Development  

NASA Technical Reports Server (NTRS)

This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane single crystal sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to boiling H2SO4:H3PO4 etchant will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology (2) elemental concentration of the Pt/Cr thin film layers and (3) etch pit formation on the sapphire surface will be presented.

Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

2004-01-01

385

Fabrication of Monolithic Sapphire Membranes for High Tc Bolometer Array Development  

NASA Technical Reports Server (NTRS)

This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to hot H2SO4:H3PO4 etchant, will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology and elemental concentration of the Pt/Cr thin film layers and (2) etch pit formation on the sapphire surface will be presented.

Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

2003-01-01

386

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

PubMed

Herein, we investigate the behaviour of the surface recombination of light-induced charge carriers during the etching of Si in alkaline (KOH) and acidic etching solutions of HF/HNO(3)/CH(3)COOH (HNA) or HF/HNO(3)/H(3)PO(4) (HNP) at different concentration ratios of HF and HNO(3) by means of photoluminescence (PL) measurements. The surface recombination velocity is strongly reduced during the first stages of etching in HF/HNO(3)-containing solutions pointing to a interface well passivated by the etching process, where a positive surface charge is induced by hole injection from NO-related surface species into the Si near-surface region (back surface field effect). This injected charge leads to a change in band bending by about 150 mV that repulses the light-induced charge carriers from the surface and therefore enhances the photoluminescence intensity, since non-radiative surface recombination is reduced. PMID:22761060

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

2012-08-27

387

Impacts of Post-metallisation Processes on the Electrical and Photovoltaic Properties of Si Quantum Dot Solar Cells  

PubMed Central

As an important step towards the realisation of silicon-based tandem solar cells using silicon quantum dots embedded in a silicon dioxide (SiO2) matrix, single-junction silicon quantum dot (Si QD) solar cells on quartz substrates have been fabricated. The total thickness of the solar cell material is 420 nm. The cells contain 4 nm diameter Si quantum dots. The impacts of post-metallisation treatments such as phosphoric acid (H3PO4) etching, nitrogen (N2) gas anneal and forming gas (Ar: H2) anneal on the cells’ electrical and photovoltaic properties are investigated. The Si QD solar cells studied in this work have achieved an open circuit voltage of 410 mV after various processes. Parameters extracted from dark I–V, light I–V and circular transfer length measurement (CTLM) suggest limiting mechanism in the Si QD solar cell operation and possible approaches for further improvement. PMID:21124642

2010-01-01

388

Molecule-Based Electrorheological Material, Electrorheological Performance and Molecule Structure  

NASA Astrophysics Data System (ADS)

Molecule-based electrorheological (ER) materials as a novel type of ER materials, a series of compounds using melamine (C3N6H6) as the substrate, have been synthesized using orthophosphoric acid (H3PO4), oxalic acid (H2C2O4), 4-toluenesulfonic acid (PTA, C7H8O3S) and 5-sulfosalicylic acid (SSA, C7H6O6S), respectively as starting materials. The ER performance and dielectric property of materials have been studied. The results show that these materials have ER activity. The unusual relationship between dielectric property and ER property of these materials was found and discussed. The composition and structure of molecule are the dominant factors, the function group plays an important role, in influencing ER performance of the molecule-based ER material.

Huo, Li; Liao, Fu-Hui; Li, Jun-Ran; Zhang, Shaohua

389

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

390

Speciation of arsenic in environmental samples of the Nha Trang Harbor, Vietnam, using HPLC coupled HG-AAS.  

PubMed

A coupled high performance liquid chromatography-hydride generation-atomic absorption spectroscopy system was used to determine the speciation of arsenic in samples from the Nha Trang Harbor, Vietnam. Concentrations of arsenic in seawater, pore water, suspended solid, and sediment were 4.12-9.81 ?g/L, 13.10-24.32 ?g/L, 1.87-6.42 ?g/g, and 3.37-9.06 ?g/g, respectively. Extraction using H(3)PO(4) + NH(2)OH·HCl and ultrasonic digestion was optimized to yield a 76-85% of total arsenic. Arsenic (III) was the most abundant species in suspended solids and sediments whereas arsenic (V) represented for 30-50% of arsenic (III) concentration. Monomethylarsonic acid and dimethylarsinic acid species were undetectable. PMID:21365299

Le, Lan Anh; Trinh, Anh Duc; Nguyen, Dinh Thuat; Bui, Minh Ly

2011-04-01

391

Fast HPLC method using ion-pair and hydrophilic interaction liquid chromatography for determination of phenylephrine in pharmaceutical formulations.  

PubMed

A rapid procedure based on a direct extraction and HPLC determination with fluorescence detection of phenylephrine in pharmaceutical sachets that include a large excess of paracetamol (65 + 1, w/w), ascorbic acid (5 + 1, w/w), and other excipients (aspartame and sucrose) was developed and validated. The final optimized chromatographic method for ion-pair chromatography used an XTerra RP18 column, 3 microm particle size, 50 x 3.0 mm id. The mobile phase consisted of a mixture of acetonitrile and buffer (10 mM sodium octane-1-sulfonate, adjusted with H3PO4 to pH 2.2; 200 + 800, v/v), with a constant flow rate of 0.3 mL/min. The separation was carried out at 30 degrees C, and the injection volume was 3 microL. Fluorescence detection was performed at excitation and emission wavelengths of 275 and 310 nm, respectively. The mobile phase parameters, such as the organic solvent fraction (acetonitrile) in mobile phase as an organic modifier, the concentration of sodium octane-1-sulfonate as a counter-ion, temperature, and pH of mobile phase, were studied. As an alternative to ion-pair chromatography, hydrophilic interaction liquid chromatography (HILIC) was investigated using a Luna HILIC column, 3 microm, 100 x 4.6 mm id. The mobile phase consisted of acetonitrile and buffer (5 mM potassium dihydrogen phosphate, adjusted with H3PO4 to pH 2.5; 750 + 250, v/v) at a flow rate of 0.8 mL/min. The separation was carried out at 25 degrees C, and the injection volume was 5 microL. The proposed method has an advantage of a very simple sample pretreatment, and is much faster than the currently utilized HPLC methods using gradient elution and UV detection. Commercial samples of sachets were successfully analyzed by the proposed HPLC method. PMID:21140654

Dousa, Michal; Gibala, Petr

2010-01-01

392

Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid.  

PubMed

Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H(3)PO(4) treatments (PA and PR+PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H(3)PO(4) was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced. PMID:18848390

Cao, Xinde; Wahbi, Ammar; Ma, Lena; Li, Bing; Yang, Yongliang

2009-05-30

393

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

PubMed

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

Navarro, Andrés; Cardellach, Esteve; Corbella, Mercé

2011-02-28

394

A capacitance sensor for water: trace moisture measurement in gases and organic solvents.  

PubMed

The determination of water in various matrices is one of the most important analytical measurements. We report on a high-resolution capacitance-based moisture sensor utilizing a thin film of a perfluorosulfonate ionomer (PFSI)-H(3)PO(4) composite in a flow-through configuration, for both gas and liquid samples. Incorporation of H(3)PO(4) into a PFSI sensing film improved the limit of detection (LOD) (signal-to-noise ratio, S/N = 3) by a factor of 16 in the gas phase to 0.075% relative humidity (RH) (dew point = -56 °C). The response time was dependent on the sensing film thickness and composition and was as low as ?60 ms. The temperature dependence of the sensor response, and its relative selectivity over alcohol and various other solvents, are reported. Measurement of water in organic solvents was carried out in two different ways. In one procedure, the sample was vaporized and swept into the detector (e.g., in a gas chromatograph (GC) without a column); it permitted a throughput of 80 samples/h. This is well-suited for higher (%) levels of water. In the other method, a flow injection analysis system integrated to a tubular dialysis membrane pervaporizer (PV-FIA) was used; the LOD for water in ethanol was 0.019% (w/w). We demonstrated the temporal course of drying of ethanol by Drierite; the PV-FIA results showed excellent correspondence (r(2) > 0.99) with results from GC-thermal conductivity detection. The system can measure trace water in many types of organic solvents; no reagent consumption is involved. PMID:22962839

Ohira, Shin-Ichi; Goto, Kayoko; Toda, Kei; Dasgupta, Purnendu K

2012-10-16

395

Solid state NMR studies of materials for energy technology  

NASA Astrophysics Data System (ADS)

Presented in this dissertation are NMR investigations of the dynamical and structural properties of materials for energy conversion and storage devices. 1H and 2H NMR was used to study water and methanol transportation in sulfonated poly(arylene ether ketone) based membranes for direct methanol fuel cells (DMFC). These results are presented in chapter 3. The amount of liquid in the membrane and ion exchange capacity (IEC) are two main factors that govern the dynamics in these membranes. Water and methanol diffusion coefficients also are comparable. Chapters 4 and 5 are concerned with 31P and 1H NMR in phosphoric acid doped PBI membranes (para-PBI and 2OH-PBI) as well as PBI membranes containing ionic liquids (H3PO4/PMIH2PO4/PBI). These membranes are designed for higher-temperature fuel cell operation. In general, stronger short and long range interactions were observed in the 2OH-PBI matrix, yielding reduced proton transport compared to that of para-PBI. In the case of H3PO4/PMIH2PO 4/PBI, both conductivity and diffusion are higher for the sample with molar ratio 2/4/1. Finally, chapter 6 is devoted to the 31P NMR MAS study of phosphorus-containing structural groups on the surfaces of micro/mesoporous activated carbons. Two spectral features were observed and the narrow feature identifies surface phosphates while the broad component identifies heterogeneous subsurface phosphorus environments including phosphate and more complex structure multiple P-C, P-N and P=N bonds.

Nambukara Kodiweera Arachchilage, Chandana K.

396

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

PubMed

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

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

2013-06-01

397

Characterization of native and anodic oxide films formed on commercial pure titanium using electrochemical properties and morphology techniques  

NASA Astrophysics Data System (ADS)

Potentiostatically anodized oxide films on the surface of commercial pure titanium (cp-Ti) formed in sulfuric (0.5 M H 2SO 4) and in phosphoric (1.4 M H 3PO 4) acid solutions under variables anodizing voltages were investigated and compared with the native oxide film. Potentiodynamic polarization and electrochemical impedance spectroscopy, EIS, were used to predicate the different in corrosion behavior of the oxide film samples. Scanning electron microscope, SEM, and electron diffraction X-ray analysis, EDX, were used to investigate the difference in the morphology between different types of oxide films. The electrochemical characteristics were examined in phosphate saline buffer solution, PSB (pH 7.4) at 25 °C. Results have been shown that the nature of the native oxide film is thin and amorphous, while the process of anodization of Ti in both acid solutions plays an important role in changing the properties of passive oxide films. Significant increase in the corrosion resistance of the anodized surface film was recorded after 3 h of electrode immersion in PSB. On the other side, the coverage ( ?) of film formed on cp-Ti was differed by changing the anodized acid solution. Impedance results showed that both the native film and anodized film formed on cp-Ti consist of two layers. The resistance of the anodized film has reached to the highest value by anodization of cp-Ti in H 3PO 4 and the inner layer in the anodized film formed in both acid solutions is also porous.

Fadl-allah, Sahar A.; Mohsen, Q.

2010-08-01

398

Photostable, amino reactive and water-soluble fluorescent labels based on sulfonated rhodamine with a rigidized xanthene fragment.  

PubMed

Highly water soluble fluorescent dyes were synthesized and transformed into new amino reactive fluorescent labels for biological microscopy. To this end, rhodamine 8 (prepared from 7-hydroxy-1,2,3,4-tetrahydroquinoline (7) and phthalic anhydride in 85 % aq. H(3)PO(4)) was sulfonated with 30 % SO(3) in H(2)SO(4) and afforded the water soluble disulfonic acid 3 a (64 %). Amidation of the carboxy group in 3 a with 2-(methylamino)ethanol in the presence of O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluroniumPF(6) (-) (HATU) led to alcohol 3 b (66 %), which was transformed into the amino reactive mixed carbonate 3 d with di(N-succinimidyl)carbonate and Et(3)N. Reaction of the carboxy group in 3 a with MeNH(CH(2))(2)CO(2)Me and N,N,N',N'-tetramethyl-O-(N-succinimidyl)-uroniumBF(4) (-) (TSTU) yielded methyl ester 13. After saponification of the aliphatic carboxy group in 13, the compound was converted into NHS-ester 3 e (using HATU and Et(3)N). Heating of 7 with trimellitic anhydride in H(3)PO(4) gave a mixture of dicarboxylic acids 14 and 15 (1:1). Regioisomer 15 was isolated, sulfonated with 30 % SO(3) in H(2)SO(4), and disulfonic acid 3 f was used for the synthesis of the mono NHS-ester 3 g, in which the sterically unhindered carboxy group was selectively activated (with N-hydroxysuccinimide, HATU, and Et(3)N). The sulfonated rhodamines 3 b, c and f are soluble in water (up to 0.1 M), have excellent photostabilities and large fluorescence quantum yields. Subdiffraction resolution images of tubulin filaments of mammalian cells stained with these dyes illustrate their applicability as labels for stimulated emission depletion microscopy and other fluorescence techniques. PMID:18058955

Boyarskiy, Vadim P; Belov, Vladimir N; Medda, Rebecca; Hein, Birka; Bossi, Mariano; Hell, Stefan W

2008-01-01

399

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

PubMed

Proton conducting gel electrolytes are very important components of clean energy devices. Phosphoric acid (PA, H(3)PO(4) · H2O) is one of the best proton conductors, but needs to be incorporated into some matrix for real device applications, such as into lyotropic liquid crystalline mesophases (LLCMs). Herein, we show that PA and nonionic surfactant (NS, C(12)H(25)(OCH(2)CH(2))(10)OH, C(12)E(10)) molecules self-assemble into PANS-LLCMs and display high proton conductivity. The content of the PANS-LLCM can be as high 75% H(3)PO(4) · H2O and 25% 10-lauryl ether (C(12)H(25)(OCH(2)CH(2))(10)OH, C(12)E(10)), and the mesophase follows the usual LLC trend, bicontinuous cubic (V1)-normal hexagonal (H1)-micelle cubic (I1), by increasing the PA concentration in the media. The PANS-LLCMs are stable under ambient conditions, as well as at high (up to 130 °C) and low (-100 °C) temperatures with a high proton conductivity, in the range of 10(-2) to 10(-6) S/cm. The mesophase becomes a mesostructured solid with decent proton conductivity below -100 °C. The mesophase can be used in many applications as a proton-conducting media as well as a phosphate source for the synthesis of various metal phosphates. As an application, we demonstrate a graphene-based optical modulator using supercapacitor structure formed by graphene electrodes and a PANS electrolyte. A PANS-LLC electrolyte-based supercapacitor enables efficient optical modulation of graphene electrodes over a range of wavelengths, from 500 nm to 2 ?m, under ambient conditions. PMID:25317477

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

2014-10-28

400

Comparative characterization of a recombinant Volvariella volvacea endoglucanase I (EG1) with its truncated catalytic core (EG1-CM), and their impact on the bio-treatment of cellulose-based fabrics.  

PubMed

Recombinant Volvariella volvacea endoglucanase 1 (EG1) and its catalytic module (EG1-CM) were obtained by expression in Pichia pastoris, purified by two-step chromatography, and the catalytic activities and binding capacities were compared. EG1 and EG1-CM exhibited very similar specific activities towards the soluble substrates carboxymethyl cellulose, lichenan and mannan, and insoluble H(3)PO(4) acid-swollen cellulose, whereas the specific activities of EG1-CM towards the insoluble substrates alpha-cellulose, Avicel and filter paper were approximately 58, 43 and 38%, respectively compared to EG1. No increase in reducing sugar release was detected in the reaction mixture supernatants after 50h exposure of filter paper, Avicel or alpha-cellulose to EG1-CM, whereas increases in the total reducing sugar equivalents (i.e. reducing sugar released into solution together with new reducing ends generated in the cellulosic substrates) in reaction mixtures were observed after 1h. In reaction mixtures containing EG1, soluble reducing sugar equivalents were detected in supernatants after 3h incubation with the insoluble cellulosic substrates. EG1-CM did not adsorb to Avicel, and the binding capacities of EG1-CM towards filter paper and H(3)PO(4) acid-swollen cellulose were 27.9-33.3% and 29.6-60.6%, respectively of values obtained with EG1 within the range of total added protein. In enzymatic deinking experiments, the ink removal rate in EG1-CM-treated samples was only slightly higher (approximately 8%), than that of untreated controls, whereas that of the EG1-treated samples was 100% higher. Bio-stoning of denim with EG1-CM resulted in increases of 48% and 40% in weight loss and indigo dye removal, respectively compared with untreated controls. These increases were considerably lower than the corresponding values of 219% and 133% obtained when samples were treated with EG1. PMID:17610980

Wu, Shufang; Ding, Shaojun; Zhou, Rui; Li, Zhongzheng

2007-07-15

401

Organometallic catalysts for primary phosphoric acid fuel cells  

NASA Technical Reports Server (NTRS)

A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

Walsh, Fraser

1987-01-01

402

OA02.02. Phytochemical constituents and antioxidative property of Musa acuminata flower as green corrosion inhibitor of mild steel in acid media  

PubMed Central

Purpose: Corrosion is a major problem that must be confronted for safety, environmental and economic reasons. Organic compounds used as corrosion inhibitors are expensive, toxic and non biodegradable. The present investigation deals with the aim of finding eco friendly and cost effective natural inhibitor. The adsorption characteristic of phytochemical of Musa acuminata ‘nendran’ flower [MAN (F)] was studied to assess the mechanism of corrosion inhibition. Method: The inhibitive effect MAN (F) extracts in 1 N HCl, 1 N H2SO4 and 1 N H3PO4 on mild steel was evaluated using conventional weight loss, electrochemical potentiodynamic polarization, AC impedance techniques and SEM analysis. Result: The inhibitor efficiency of MAN (F) extracts increases with an increase in concentration but decreased with temperature. The potentiodynamic polarization curves reveal that MAN (F) acts as a mixed type inhibitor and adsorption of extract follows Temkin adsorption. Surface studies SEM confirmed the efficiency of the flower extract as corrosion inhibitor. The flower extract was an excellent corrosion inhibitor for mild steel showing a maximum efficiency of 97.16%, 95.01% and 70.03 % in 1N HCl, H2SO4 and H3PO4 respectively at 5 hours in 2 % v/v extract. Conclusion: In traditional medicine of India and the ancient Persia this Golden fruit called the ‘fruit of wise’ is regarded as nature's secret of perpetual youth. Musa acuminata ‘nendran’ (AAB) is good source of vitamins, potassium, magnesium, phosphorus, calcium and iron. All parts of the banana plant have medicinal applications. The flowers are used in treatment of bronchitis, constipation, ulcers, diabetic, reduce painful and excess menstrual bleeding and enhance milk supply in lactating mothers. The phytochemical components of Musa acuminata flower like tannins, flavonoids, saponin, alkaloid and phenols are found to be responsible for inhibiting corrosion. The natural flavonoids present in the flower extract exhibit antioxidative activity that stop oxidation and hence corrosion.

Gunavathy, N

2013-01-01

403

Negative ion fragmentations of deprotonated peptides containing post-translational modifications. An unusual cyclisation/rearrangement involving phosphotyrosine; a joint experimental and theoretical study.  

PubMed

The characteristic fragmentations of a pTyr group in the negative ion electrospray mass spectrum of the [M-H](-) anion of a peptide or protein involve the formation of PO(3) (-) (m/z 79) and the corresponding [(M-H)(-)-HPO(3)](-) species. In some tetrapeptides where pTyr is the third residue, these characteristic anion fragmentations are accompanied by ions corresponding to H(2)PO(4) (-) and [(M-H)(-)-H(3)PO(4)](-) (these are fragmentations normally indicating the presence of pSer or pThr). These product ions are formed by rearrangement processes which involve initial nucleophilic attack of a C-terminal -CO(2) (-) [or -C(==NH)O(-)] group at the phosphorus of the Tyr side chain [an S(N)2(P) reaction]. The rearrangement reactions have been studied by ab initio calculations at the HF/6-31+G(d)//AM1 level of theory. The study suggests the possibility of two processes following the initial S(N)2(P) reaction. In the rearrangement (involving a C-terminal carboxylate anion) with the lower energy reaction profile, the formation of the H(2)PO(4) (-) and [(M-H)(-)-H(3)PO(4)](-) anions is endothermic by 180 and 318 kJ mol(-1), respectively, with a maximum barrier (to a transition state) of 229 kJ mol(-1). The energy required to form H(2)PO(4) (-) by this rearrangement process is (i) more than that necessary to effect the characteristic formation of PO(3) (-) from pTyr, but (ii) comparable with that required to effect the characteristic alpha, beta and gamma backbone cleavages of peptide negative ions. PMID:19412918

Wang, Tianfang; Andreazza, Hayley J; Bilusich, Daniel; Bowie, John H

2009-06-01

404

Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors  

NASA Astrophysics Data System (ADS)

Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics.Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics. Electronic supplementary information (ESI) available: Equations and characterization. SEM images of GGO, XRD and XPS of Bi2O3 NTs, HRTEM images and EDX Spectra of Bi2O3 NT5-GF, CV curves of Bi2O3NT5-GF, Bi2O3 NTs and bismuth nitrate in three-electrode system (vs. Ag/AgCl). CV and GCD curves of Bi2O3 NT1-GF and Bi2O3 NT3-GF. See DOI: 10.1039/c4nr02615b

Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

2014-07-01

405

Increased digestibility of bagasse by pretreatment with alkalis and steam explosion  

SciTech Connect

Alkali treatment and steam explosion of bagasse were investigated in order to develop economical and effective methods of increasing the digestibility of bagasse. The treated bagasse was to be used as a substrate for the production of volatile fatty acids by anaerobic acidogenic bacteria. The alkalis examined were NaOH, NH3 (aqueous), NaOH + NH3, Ca(OH)2, and Ca(OH)2 + Na2CO3, at ambient temperature and in combination with steam explosion at 200 degrees C, 6.9 MPa, and 5 min cooking times. Digestibilities of up to 733 g organic matter (OM)/kg bagasse dry matter (DM) were obtained for bagasse treated with NaOH and Ca(OH)2 + Na2CO3; less than 430 g OM was obtained for bagasse treated with aqueous NH3; and up to 724 g OM was obtained for bagasse treated with Ca(OH)2. This digestibility was only achieved by using high concentrations of Ca(OH)2, i.e., 180-300 g/kg bagasse. Steam explosion increased the digestibility of bagasse up to 740 g OM in the presence of alkali but only to 610 g OM in the absence of alkali. The digestibility of bagasse without pretreatment was 190 g OM/kg bagasse DM. More than one-half the hemicellulose present was solubilized by pretreatment. The composition of the liquid fraction of steam-exploded material was examined and contained mainly xylose monomers and oligomers (112 g/kg original bagasse DM) and acetic acid (33 g/kg original DM). The relative costs of the alkalis used were obtained for the United States, Australia, and Europe. Lime (Ca(OH)2) was the least expensive alkali per unit of additional digestible OM obtained. Ammonia was the most expensive alkali to use, except in the United States where the difference in its cost relative to other alkalis was smaller. However, ammonia provides organic nitrogen for microbial growth, and could be recycled. With acidogenic fermentations, alkali is able to double as a neutralizing agent during fermentation.

Playne, M.J.

1984-01-01

406

Influence of calcium compounds on the mechanical properties of fly ash geopolymer pastes.  

PubMed

The influence of calcium compounds (CaO and Ca(OH)(2)) on the mechanical properties of fly ash based geopolymers has been studied. Calcium compounds were substituted in fly ash at 1, 2 and 3 wt%, respectively. Curing of the geopolymers was performed at ambient temperature (20 degrees C) and 70 degrees C. Addition of calcium compounds as a fly ash substitute improved mechanical properties for the ambient temperature cured samples while decreasing properties for the 70 degrees C cured samples. Seven days compressive strength of the ambient temperature cured samples increased from 11.8 (2.9) to 22.8 (3.8)MPa and 29.2 (1.1)MPa for 3% CaO and 3% Ca(OH)(2) additions, respectively. PMID:19201089

Temuujin, J; van Riessen, A; Williams, R

2009-08-15

407

Laboratory Synthesized Calcium Oxide and Calcium Hydroxide Grains: A Candidate to Explain the 6.8 Micron Band  

NASA Technical Reports Server (NTRS)

We will demonstrate that CaO and Ca(OH)2 are excellent candidates to explain the 6.8 microns feature, which is one of the most obscure features in young stellar objects. We discuss the condensation of CaO grains and the potential formation of a Ca(OH)2 surface layer. The infrared spectra of these grains are compared with the spectra of fifteen young stellar objects. We note that CaO-rich grains are seen in all meteoritic CAIs (calcium-aluminum-rich inclusions) and the 6.8 micron feature has only been observed in young stellar objects. Therefore, we consider CaO grains to be a plausible candidate to explain the 6.8 microns feature and hypothesize that they are produced in the hot interiors of young stellar environments.

Kimura, Yuki; Nuth, Joseph A., III

2005-01-01

408

Rapid Carbonation for Calcite from a Solid-Liquid-Gas System with an Imidazolium-Based Ionic Liquid  

PubMed Central

Aqueous carbonation of Ca(OH)2 is a complex process that produces calcite with scalenohedral calcite phases and characterized by inadequate carbonate species for effective carbonation due to the poor dissolution of CO2 in water. Consequently, we report a solid-liquid-gas carbonation system with an ionic liquid (IL), 1-butyl-3-methylimidazolium bromide, in view of enhancing the reaction of CO2 with Ca(OH)2. The use of the IL increased the solubility of CO2 in the aqueous environment and enhanced the transport of the reactive species (Ca2+ and CO32?) and products. The presence of the IL also avoided the formation of the CaCO3 protective and passivation layer and ensured high carbonation yields, as well as the production of stoichiometric rhombohedral calcite phases in a short time. PMID:24968273

Ibrahim, Abdul-Rauf; Vuningoma, Jean Bosco; Huang, Yan; Wang, Hongtao; Li, Jun

2014-01-01

409

Soil pH, rhizobia, and vesicular-arbuscular mycorrhizae inoculation effects on growth and heavy metal uptake of alfalfa ( Medicago sativa L.)  

Microsoft Academic Search

The interaction between soil pH and inoculation with rhizobia and vesicular-arbuscular mycorrhizae (VAM) was studied in an industrially polluted soil contaminated with high levels of Zn and Cd. A silt loam soil (pH 6.7) was amended with Ca(OH)2 or elemental S to adjust the soil pH to 4.3, 5.3, 6.0, and 7.2. Alfalfa (Medicago sativa L.) was planted in each

M. El-Kherbawy; J. S. Angle; A. Heggo; R. L. Chaney

1989-01-01

410

Efficacy of chemical treatments in eliminating Salmonella and Escherichia coli O157:H7 on scarified and polished alfalfa seeds.  

PubMed

Alfalfa seeds are sometimes subjected to a scarification treatment to enhance water uptake, which results in more rapid and uniform germination during sprout production. It has been hypothesized that this mechanical abrasion treatment diminishes the efficacy of chemical treatments used to kill or remove pathogenic bacteria from seeds. A study was done to compare the effectiveness of chlorine (20,000 ppm), H2O, (8%), Ca(OH)2 (1%), Ca(OH)2 (1%) plus Tween 80 (1%), and Ca(OH)2 (1%) plus Span 20 (1%) treatments in killing Salmonella and Escherichia coli O157:H7 inoculated onto control, scarified, and polished alfalfa seeds obtained from two suppliers. The influence of the presence of organic material in the inoculum carrier on the efficacy of sanitizers was investigated. Overall, treatment with 1% Ca(OH)2 was the most effective in reducing populations of the pathogens. Reduction in populations of pathogens on seeds obtained from supplier I indicate that chemical treatments are less efficacious in eliminating the pathogens on scarified seeds compared to control seeds. However, the effectiveness of chemical treatment in removing Salmonella and E. coli O157:H7 from seeds obtained from supplier 2 was not markedly affected by scarification or polishing. The presence of organic material in the inoculum carrier did not have a marked influence on the efficacy of chemicals in reducing populations of test pathogens. Additional lots of control, scarified, and polished alfalfa seeds of additional varieties need to be tested before conclusions can be drawn concerning the impact of mechanical abrasion on the efficacy of chemical treatment in removing or killing Salmonella and E. coli O157:H7. PMID:11601695

Holliday, S L; Scouten, A J; Beuchat, L R

2001-10-01

411

Highly Ordered TiO2 Nanotubes Filled by Hydroxyapatite Nanoparticles for Biomedical Applications  

NASA Astrophysics Data System (ADS)

Hydroxyapatite-containing coatings were prepared on a titanium substrate by chemical treatment of the anodic films with TiO2 nanotube arrays in Ca(OH)2 and (NH4)2HPO4 solutions using successive ion layer adsorption and reaction. The composite coatings obtained offer a good adhesion to the titanium implant and a high biocompatibility due to embedding hydroxyapatite nanoparticles into the vertical TiO2 nanopores.

Ulasevich, S. A.; Poznyak, S. K.; Skorb, E. V.; Kulak, A. I.

2013-05-01

412

Highly active catalysts from inexpensive raw materials for coal gasification  

Microsoft Academic Search

The present review article focuses on novel methods of converting inexpensive raw materials to active catalysts for low-temperature coal gasification, which can produce clean fuels and valuable feedstock with high thermal efficiency. Precipitation methods using NH3, urea, and Ca(OH)2 make it possible to prepare active, Cl-free iron catalysts on brown coals from an aqueous solution of FeCl3 as the major

Yasuo Ohtsuka; Kenji Asami

1997-01-01

413

The effects of pH regulation upon the release of sulfate from ferric precipitates formed in acid mine drainage  

Microsoft Academic Search

`Batch experiments' (25:1 v:w) were used to test the effects of pH upon the release of SO?24 from ferric precipitates formed in acid mine drainage (AMD) in southeastern Kentucky. Analytical grade CaO [`quicklime'], Ca(OH)2 [hydrated lime] and CaCO3 [referred to as `limestone'] were used as alkalinity generating agents and were mixed with ferric precipitates composed of amorphous iron oxyhydroxides, jarosite

Seth Rose; W. Crawford Elliott

2000-01-01

414

Removal of Nickel onto Alkali Treated Rice Bran  

Microsoft Academic Search

Different bases were used for the pretreatment of Rice bran biomass. Pretreatment with bases such as NaOH, Ca(OH)2 and Al(OH)3 were found to improve biosorption capacity. But in Rice bran, treatment with 0.5 M NaOH increased its nickel selective adsorption\\u000a ability very much. The main binding site of nickel in NaOH treated cells is assumed to be carboxylic, hydroxyl, sulphate,\\u000a phosphate

Muhammad Nadeem Zafar; Imran Abbas; Raziya Nadeem; Munir Ahmad Sheikh; Muhammad Afzal Ghauri

2009-01-01

415

Mass Transfer Model of the Wet Flue Gas Desulfurization with Lime  

Microsoft Academic Search

On the basis of the two-film theory, dynamical mass transfer model was deduced for the wet flue gas desulfurization (FGD) with lime, and the relation between the conversion ratio of calcium hydroxide (Ca(OH)2) and reaction time is set up. It is convenient for improving the residence time in the absorption tower in order to increase desulfurization efficiency and absorbent utilization

Ru-shan Ren; Yun-nen Chen; Fa-en Shi; Xue-min Huang

2009-01-01

416

Calcination and sintering models for application to high-temperature, short-time sulfation of calcium-based sorbents  

Microsoft Academic Search

To simulate the staged availability of transient high surface area CaO observed in high-temperature flow-reactor data, the paper describes the rate of calcination of CaCOâ or Ca(OH)2, using an empirical modification of the shrinking-core model. The physical model depicts particle decomposition by the shrinking-core mechanism. The subsequent time-dependent decrease in CaO reactivity (surface area and porosity) due to sintering is

Corey R. Milne; Geoffrey D. Silcox; David W. Pershing; David A. Kirchgessner

1990-01-01

417

Effect of calcium hydroxide-based materials on periapical tissue healing and orthodontic root resorption of endodontically treated teeth in dogs.  

PubMed

This study evaluated periapical tissue healing and orthodontic root resorption of endodontically treated teeth sealed with calcium hydroxide in dogs. The sample consisted of three contralateral pairs of maxillary incisors and two contralateral pairs of mandibular incisors in each of two dogs using a split mouth design. After biomechanical preparation of the teeth in the first group (n = 10), a Ca(OH)(2) dressing was placed for 14 days before root canal filling with Ca(OH)(2)-based sealer (Sealapex) and gutta-percha points. In the second group (n = 10), root canals were obturated immediately after the mechanical preparation with gutta-percha points and zinc oxide and eugenol (ZOE)-based sealer (Endofill). After completion of endodontic treatment, the teeth were moved with an orthodontic appliance with a calibrated force of 200 g, reactivated every 21 days. After 105 days, the animals were killed and the teeth were removed upon completion of active treatment, without a period of recovery, and prepared for histomorphological analysis. All sections of each tooth were graded subjectively on a scale from one to four to obtain the average of the 16 histomorphological parameters analysed. Evaluation of the differences between the two treatment protocols was made with Mann-Whitney U-test. It was observed that the teeth treated with Ca(OH)(2)-based materials provided better outcomes (P = 5%), with complete repair of all root resorption areas, high rate of biological closure of the main canal and apical accessory canals by newly formed cementum, less intense and extensive chronic inflammatory infiltrate, and better organization of the periodontal ligament. Under the tested conditions, Ca(OH)(2)-based materials had a favourable action on periapical tissue healing and repair of orthodontic root resorption in endodontically treated dogs' teeth. PMID:19290903

de Souza, Ricardo Sampaio; de Souza, Valdir; Holland, Roberto; Gomes-Filho, João Eduardo; Murata, Sueli Satomi; Sonoda, Celso Koogi

2009-04-01

418

A study of calcium zincate as negative electrode materials for secondary batteries  

Microsoft Academic Search

The properties of calcium zincate as negative electrode materials for secondary batteries were examined by powder microelectrode, cyclic voltammetry, charge–discharge cycle measurements and X-ray diffraction (XRD) analysis. The results show that the cycleability of calcium zincate is obviously superior to that of ZnO and that of the mixture of ZnO and Ca(OH)2 (the molar ratio of Zn:Ca=2:1). Calcium zincate forms

Jingxian Yu; Hanxi Yang; Xinping Ai; Xiaoming Zhu

2001-01-01

419

CONSUMPTION OF SIMULATED ACID MINE WATER BY SHEEP  

Microsoft Academic Search

Water consumption by sheep in 48-h periods was measured in three replicated experiments. Intake was expressed as ml, kg body weight-'73-d-1 and treatments were compared with intake of tap water or distilled water in no-choice situations. Neutralizing two acid mine drainage (AMD) polluted waters having pH values of 2.4 and 2.8, with Ca(OH) 2 did not make either as acceptable

D. J. Horvath

2010-01-01

420

Ca\\/Ag bilayer cathode for transparent white organic light-emitting devices  

Microsoft Academic Search

We have demonstrated that the compositional modification of the Ca\\/Ag films is principally responsible for a high transmittance (over 70% in the visible range) and low sheet resistance (10 12 Omega\\/sq). X-ray photoelectron spectroscopy (XPS) sputter depth profiling of Ca\\/Ag structure reveals the presence of Ca(OH)2 and Ca metal. A chemical model of the Ca\\/Ag cathode is proposed. Using transparent

C. J. Lee; R. B. Pode; J. I. Han; D. G. Moon

2007-01-01

421

Hydrogen production from coal by separating carbon dioxide during gasification  

Microsoft Academic Search

Hydrogen generation during the reaction of a coal\\/CaO mixture with high pressure steam was investigated using a flow-type reactor. Coal, CaO and CO reactions with steam, and CO2 absorption by Ca(OH)2 or CaO occurred simultaneously in the experiment. It was found that H2 was the primary resultant gas, comprising about 85% of the reaction products. CO2 was fixed into CaCO3

Shiying Lin; Michiaki Harada; Yoshizo Suzuki; Hiroyuki Hatano

2002-01-01

422

Hydrogen production by biomass gasification in supercritical or subcritical water with Raney-Ni and other catalysts  

Microsoft Academic Search

Gasification of peanut shell, sawdust and straw in supercritical or subcritical water has been studied in a batch reactor\\u000a with the presence of a series of Raney-Ni and its mixture with ZnCl2 or Ca(OH)2. The main gas products were hydrogen, methane, carbon dioxide, and a small amount of carbon monoxide. Different types of\\u000a Raney-Ni, containing different metal components such as

Aixia Pei; Lisheng Zhang; Bizheng Jiang; Liejin Guo; Ximin Zhang; Youjun Lv; Hui Jin

2009-01-01

423

The effect of hydrogen peroxide solution on SO 2 removal in the semidry flue gas desulfurization process  

Microsoft Academic Search

The present study attempts to use hydrogen peroxide solution to humidify Ca(OH)2 particles to enhance the absorption of SO2 to achieve higher removal efficiency and to solve the valuable reuse of the reaction product in the semidry flue gas desulfurization (FGD) process. Experiments were carried out to examine the effect of various operating parameters including hydrogen peroxide solution concentration, Ca\\/S

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

2009-01-01

424

The effect of H2O gas on volatilities of planet-forming major elements. I - Experimental determination of thermodynamic properties of Ca, Al, and Si-hydroxide gas molecules and its application to the solar nebula  

Microsoft Academic Search

The vapor pressures of Ca(OH)2(g), Al(OH)3(g), and Si(OH)4(g) molecules in equilibrium with solid calcium-, aluminum, and silicon-oxides, respectively, were determined, and were used to derive the heats of formation and entropies of these species, which are expected to be abundant under the currently postulated physical conditions in the primordial solar nebula. These data, in conjunction with thermodynamic data from literature,

Akihiko Hashimoto

1992-01-01

425

Bacterial Reduction in Infected Root Canals Treated With 2.5% NaOCl as an Irrigant and Calcium Hydroxide\\/Camphorated Paramonochlorophenol Paste as an Intracanal Dressing  

Microsoft Academic Search

This clinical study investigated the bacterial reduction after instrumentation using 2.5% sodium hypochlorite (NaOCl) as an irrigant and further interappointment dressing with a calcium hydroxide (Ca(OH)2)\\/camphorated paramonochlorophenol (CPMC) paste. Eleven teeth with primary intraradicular infections and chronic apical periodontitis selected according to stringent inclusion\\/exclusion criteria followed in the study. Bacterial samples were taken before treatment (S1), after chemomechanical preparation using

José F. Siqueira; Karen M. Magalhães; Isabela N. Rôças

2007-01-01

426

Isolation of 9Z beta-carotene from Dunaliella bardawil and its stereoselective synthesis.  

PubMed

An isolation of 9Z beta-carotene from Dunaliella bardawil was accomplished by low-pressure column chromatography with Ca(OH)2 column. Furthermore, it was stereoselectively synthesized by Wittig reaction between the C10-phosphonium salt 2 and 9Z beta-apo-8'-carotenal 1, which was prepared by Emmons-Horner reaction of 9Z beta-ionylideneacetaldehyde 3 with phosphonates 6 and 7 or 8a and 9. PMID:10360241

Yamano, Y; Yoshizawa, M; Ito, M

1999-01-01

427

Growth of calcium phosphate on surface-modified cotton  

Microsoft Academic Search

A study of the growth of amorphous calcium phosphate on surface-modified cotton fibres by a combination of scanning electron microscopy\\/electron diffraction X-ray analysis, micro-FTIR and X-ray photoelectron spectroscopy is reported. Cotton fibres phosphorylated by the urea\\/phosphorous acid method and then soaked in saturated Ca(OH)2 for approximately one week were found to stimulate the growth of a calcium phosphate coating on

M. R. Mucalo; Y. Yokogawa; M. Toriyama; T. Suzuki; Y. Kawamoto; F. Nagata; K. Nishizawa

1995-01-01

428

Inhibition of hydrogen sulfide generation from disposed gypsum drywall using chemical inhibitors.  

PubMed

Disposal of gypsum drywall in landfills has been demonstrated to elevate hydrogen sulfide (H(2)S) concentrations in landfill gas, a problem with respect to odor, worker safety, and deleterious effect on gas-to-energy systems. Since H(2)S production in landfills results from biological activity, the concept of inhibiting H(2)S production through the application of chemical agents to drywall during disposal was studied. Three possible inhibition agents - sodium molybdate (Na(2)MoO(4)), ferric chloride (FeCl(3)), and hydrated lime (Ca(OH)(2)) - were evaluated using flask and column experiments. All three agents inhibited H(2)S generation, with Na(2)MoO(4) reducing H(2)S generation by interrupting the biological sulfate reduction process and Ca(OH)(2) providing an unfavorable pH for biological growth. Although FeCl(3) was intended to provide an electron acceptor for a competing group of bacteria, the mechanism found responsible for inhibiting H(2)S production in the column experiment was a reduction in pH. Application of both Na(2)MoO(4) and FeCl(3) inhibited H(2)S generation over a long period (over 180 days), but the impact of Ca(OH)(2) decreased with time as the alkalinity it contributed was neutralized by the generated H(2)S. Practical application and potential environmental implications need additional exploration. PMID:21592650

Xu, Qiyong; Townsend, Timothy; Bitton, Gabriel

2011-07-15

429

Chemical phosphorus removal: a clean strategy for piggery wastewater management in Brazil.  

PubMed

The intensive production of animal protein is known to be an environmental polluting activity, especially if the wastewater produced is not managed properly. Swine production in Brazil is growing, and technologies to manage all pollutants present in the wastewater effluent are needed. This work presents a case of study of phosphorus (P) removal from piggery wastewater using Ca(OH)2, and demonstrates the feasibility of this strategy for P management. The effluent of a swine manure treatment plant was treated with Ca(OH)2. According to the addition of Ca(OH)2 the pH of the effluent ranged from 8.0 to 10.0. Different conditions of sludge dewatering were evaluated, and the chemical composition of sludge was investigated. Ion chromatography analysis of effluent samples showed that 92% of total P (TP) was present as soluble P (SP) whereas 75% of SP species were present as phosphate. The efficiency of P removal was typically 90% at pH 8.5 and higher than 98% at pH 10.5. The sludge was separated by sedimentation, centrifugation or filtration and dried. The TP content of dried sludge was 9.3% (w/w). X-ray diffraction analysis of the dry sludge showed the presence of amorphous compounds of Ca and P, which is an indication that the sludge obtained from the swine manure treatment has a potential for application as biofertilizer. PMID:22988628

Fernandes, Gabriela Wendler; Kunz, Airton; Steinmetz, Ricardo Luís Radis; Szogi, Ariel; Vanotti, Matias; Flores, Erico Marlon de Moraes; Dressler, Valderi Luiz

2012-01-01

430

The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator.  

PubMed

Abstract Objective. The aim of this study was to evaluate the effect of residual calcium hydroxide [Ca(OH)2] on the accuracy of an electronic apex locator (EAL). Materials and methods. Working lengths (WLs) of 56 extracted maxillary incisors were determined initially by two different methods. The first method used the 'APEX' reading of the EAL as a reference point, 0.5 mm was subtracted and recorded as WL0. The second method used the '0.5' reading and the score was recorded as WL0.5 without subtraction. The roots were prepared to WL0 and divided randomly into three experimental groups (n = 16) (1 mm in group A, 2 mm in group B and 4 mm in group C) and a control (n = 8). Specimens in all experimental groups were filled with Ca(OH)2 paste. Following its removal, WLs were re-determined with the same methods. Results. In group C, pre/post WLs were significantly different (p < 0.05). No significant difference was observed between the other experimental groups and the control group. Conclusion. Accuracy of EAL decreased proportionally with the amount of paste remaining at the ±0.5-mm tolerance level. Ca(OH)2 paste remnants may cause incorrect EAL readings. PMID:25247720

Ustun, Yakup; Uzun, Ozgur; Er, Ozgur; Canakc?, Burhan Can; Topuz, Ozgur

2015-02-01

431

Removal of boron from wastewater by the hydroxyapatite formation reaction using acceleration effect of ammonia.  

PubMed

The mechanism was discussed for the removal of boron by the hydroxyapatite (HAp) formation reaction using Ca(OH)(2) and (NH(4))(2)HPO(4) in room temperature. Time required to remove boron was 20 min by adding Ca(OH)(2) and (NH(4))(2)HPO(4) for the remaining boron to below 1mg/L. The removal rate of boron was controlled by the HAp precipitate formation and the presence of ammonia. From the XRD patterns and SEM images, HAp could be confirmed in the precipitate product. The reaction between borate ions and calcium hydroxide was accelerated by dehydration with ammonia; the borate-calcium hydroxide compound coprecipitated with resulting HAp. Although the removal of boron decreased in the presence of sulfate, phosphate, and aluminum, these effects could be prevented by adding excess Ca(OH)(2). Interference of fluoride ions was eliminated by adding Al(3+). Sodium alpha-olefin sulfonate was the most effective coagulant for HAp precipitation. The proposed boron removal method has several advantages about treating time and ability of boron removal. The method was successfully applied to the real hot spring wastewater. PMID:22981286

Yoshikawa, Eishi; Sasaki, Atsushi; Endo, Masatoshi

2012-10-30

432

A chemical equilibrium model of solution behavior and solubility in the H-Na-K-Ca-OH-Cl-HSO 4-SO 4-H 2O system to high concentration and temperature  

NASA Astrophysics Data System (ADS)

This paper describes a chemical model for calculating solute and solvent activities and solid-liquid equilibria in the H-Na-K-Ca-OH-Cl-HSO 4-SO 4-H 2O system from low to high solution concentration within the 0° to 250°C temperature range. The solubility modeling approach of Harvie and Weare (1980) and Harvie et al. (1984), and their implementation of the Pitzer (1973) specific interaction equations are employed. This model expands the variable temperature H-Na-K-OH-Cl-HSO 4-SO 4-H 2O model of Christov and Moller (2004) by evaluating the Ca 2+-acid/base binary and ternary solution parameters and the chemical potentials of three basic calcium solid phases: Ca(OH) 2(s), CaCl 2.Ca(OH) 2.H 2O(s), and CaCl 2.3Ca(OH) 2.13H 2O and three calcium chloride hydrates (CaCl 2.nH 2O; n = 6, 4, 2). Comparisons of solubility and activity predictions with experimental data used and not used in model parameterization are given. Limitations of the model due to data insufficiencies are discussed.

Christov, Christomir; Moller, Nancy

2004-09-01

433

Continuous precipitation of calcium carbonate using sonochemical reactor.  

PubMed

The continuous production of calcium carbonate (CaCO3) by precipitation method at room temperature was carried out in a stirred reactor under ultrasonic environment and was compared with the conventional stirring method. The effect of various operating parameters such as Ca(OH)2 slurry concentration, CO2 flow rate and Ca(OH)2 slurry flow rate on the particle size of CaCO3 was investigated. The calcium carbonate particles were characterized by Fourier transform infrared (FTIR), wide angle X-ray diffraction (WXRD) and particle size. The morphology was studied by using scanning electron microscopic (SEM) images. The particle size obtained in the presence of ultrasonic environment was found to be smaller as compared to conventional stirring method. The particle size is found to be reduced with an increase in the concentrations of Ca(OH)2 and increased with increasing CO2 flow rate for both the methods. The slurry flow rate had a major effect on the particle size and the particle size decreased with increased slurry flow rate. Only calcite phase of CaCO3 was predominantly present as confirmed by the characterization techniques for both the preparation methods. In most of the cases rhombohedral calcite particles were observed. PMID:25534035

Shirsath, S R; Sonawane, S H; Saini, D R; Pandit, A B

2015-05-01

434

Comparison of two types of municipal solid waste incinerator fly ashes with different alkaline reagents in washing experiments.  

PubMed

In this study, we propose a "washing-calcination-conversion of washed fly ash into cement material with bottom ash" (WCCB) system to reduce the amount of fly ash that must be specially treated so it can be used as raw cement material. Calcium hydroxide (Ca(OH)2) is widely used in air-pollution control devices of incinerators while sodium bicarbonate (NaHCO3) is not. We conducted single-, double-, and triple-washing experiments to compare the washing characteristics of two types of fly ash. Unlike NaHCO3 fly ash, Ca(OH)2 fly ash has almost twice as much washed residue and almost 2.5 times more chlorine after the same washing procedure. After washing once, the washing frequency is also important for NaHCO3 fly ash, while the mixing time and liquid/solid ratio are more critical for Ca(OH)2 fly ash. The use of NaHCO3 is more suitable for the WCCB system. PMID:18539449

Zhu, Fenfen; Takaoka, Masaki; Oshita, Kazuyuki; Takeda, Nobuo

2009-01-01

435

Effect of a calcium-silicate-based restorative cement on pulp repair.  

PubMed

In cases of pulp injury, capping materials are used to enhance tertiary dentin formation; Ca(OH)(2) and MTA are the current gold standards. The aim of this study was to evaluate the capacity of a new calcium-silicate-based restorative cement to induce pulp healing in a rat pulp injury model. For that purpose, cavities with mechanical pulp exposure were prepared on maxillary first molars of 27 six-week-old male rats, and damaged pulps were capped with either the new calcium-silicate-based restorative cement (Biodentine), MTA, or Ca(OH)(2). Cavities were sealed with glass-ionomer cement, and the repair process was assessed at several time-points. At day 7, our results showed that both the evaluated cement and MTA induced cell proliferation and formation of mineralization foci, which were strongly positive for osteopontin. At longer time-points, we observed the formation of a homogeneous dentin bridge at the injury site, secreted by cells displaying an odontoblastic phenotype. In contrast, the reparative tissue induced by Ca(OH)(2) showed porous organization, suggesting a reparative process different from those induced by calcium silicate cements. Analysis of these data suggests that the evaluated cement can be used for direct pulp-capping. PMID:22983409

Tran, X V; Gorin, C; Willig, C; Baroukh, B; Pellat, B; Decup, F; Opsahl Vital, S; Chaussain, C; Boukpessi, T

2012-12-01

436

Comparison of Seven Chemical Pretreatments of Corn Straw for Improving Methane Yield by Anaerobic Digestion  

PubMed Central

Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS ?1 in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost. PMID:24695485

Song, Zilin; GaiheYang; Liu, Xiaofeng; Yan, Zhiying; Yuan, Yuexiang; Liao, Yinzhang

2014-01-01

437

The generation of HCl in the system NaCl-KCl-H{sub 2}O-quartz at 600{degrees}C: Implications regarding HCl in natural systems at lower temperatures  

SciTech Connect

In experiments at 600°C in the system NaCI-KCI-H2O, within the analytical uncertainty, stoichiometric quantities of Cl and total alkali metals (Na+K) appear to dissolve in steam coexisting with chloride-rich brine at high pressures in the absence of solid salt. In contrast, at lower pressures, where steam coexists with precipitated salts, significant excess chloride as associated hydrogen chloride (HCI°) dissolves in steam. The HCI° appears to be generated by the reaction of solid NaCl(s) (halite) with steam, producing solid NaOH(s) that diffuses into halite, forming a solid solution. Where HCI° is present highly associated NaOH° as well as associated NaCI° appear to dissolve in steam, and the solubility of each is increased as the mole fraction of NaOH(s) in halite increases. In our quasi-static experiments, compared to dynamic flow-through experiments of others, higher initial ratios of H2O/NaCI have resulted in higher mole fractions of NaOH(s) in solid solution in halite and, accordingly, higher solubilities of NaCI" and NaOH" dissolved in steam. Addition of quartz to the system NaCI-KCI-H2O results in the formation of sodium disilicate by reaction of silica with NaOH(s) and an order of magnitude increase in the concentration of HCl° dissolved in steam. In natural hydrothermal systems at lower temperatures where brine or brine plus steam are present in the absence of precipitated salt, the pH of the brine is controlled mainly by base exchange reactions involving a variety of silicates that fix Na+/H+ and K+/H+ activity ratios. Where feldspars are present pH values generally are near neutral. Where mica, but no feldspar is present pH values may become only moderately acid. High acidity in salt-absent brine systems occurs only where all feldspars and mica have been altered to other minerals (generally pyrophyllite/ kaolinite or alunite). The situation changes significantly when salt precipitates. Hydrolysis produces HCI° by the reaction of water with NaCl when halite is present. The NaOH(s) that is produced as a byproduct is likely to react with quartz plus various alumino-silicates, producing a variety of alteration products and allowing steam to become greatly enriched in HCl° compared to the composition of steam that is attained in the simple system NaCI-KCI-H2O with halite present. Also, when a natural high-temperature hydrothermal system changes from one in which the pore fluid is brine to one in which the pore fluid is dry steam there is a drastic change in Na+/H+ and K+/H+ activity ratios in the pore fluid because the hydrogen ions that were predominantly dissociated species in the brine become predominantly associated species in steam. The net result is the stabilization of alkali feldspars in contact with steam that may contain appreciable HCI° that is produced by the reaction of precipitated salt with the steam.

Fournier, Robert O.; Thompson, J. Michael

1993-01-28

438

(4 mg) was concentrated by vacuum dialysis against 100 mM KCl, 100 mM NaCl, 5 mM potassium phosphate (pH  

E-print Network

)diplatinum nitrate derivative (PIP) at 7.0 Ã? resolu- tion. Single-isomorphous-replacement phases were then used calculated by using PIP and SmCl3-free data sets; for the latter, we refined negative Sm3 occupancies) either on image plates or on the Quantum-4 CCD detector. All data were processed with the HKL suite (26

Vale, Ronald D.

439

Phase relations in the system NaCl-KCl-H2O II: Differential thermal analysis of the halite liquidus in the NaCl-H2O binary above 450??c  

USGS Publications Warehouse

Thermal analysis of the halite liquidus in the system NaCl-H2O has been conducted for NaCl mole fractions (XNaCl) greater than 0.25 (i.e., > 50 wt. % NaCl) at pressures between 0.3 and 4.1 kb and temperatures greater than 450??C. The position of the liquidus was located by differential thermal analysis (DTA) of cooling scans only, as heating scans did not produce definitive DTA peaks. The dP/dT slope of the liquidus is positive and steep at high pressures, but at high XNaCl, and pressures below 0.5 kb it appears to reverse slope and intersects the three-phase curve (liquid-halite-vapour) at a shallow angle. However, due to the complex nature of the DTA signal when P <- 0.5 kb, there is considerable doubt about exactly what event has been recorded in the experiments conducted at these low pressures. The solubility of halite can be expressed as a function of the mole-fractional-based activity of NaCl in the liquid phase (L) in temperature (T, ??K) and pressure (P, bars) In ??NaCl(L.T.P) = -19.884 - 0.001275T - 1388 T + 3.2305 In (T) - 0.07574PT Our liquidus data (based on 10 compositions) above 500 bars for these brines were combined with this equation to generate activity coefficients of NaCl which were fit within their experimental uncertainties to the following one parameter Margules equation In ??NaCl(L.T.P) = (0.7268 - 695.7 T - 0.1217PT)(1 - XNaCl)2. Concentrated solutions of NaCl show negative deviations from ideality which rapidly increase in magnitude with decreasing XNaCl. ?? 1983.

Gunter, W.D.; Chou, I.-M.; Girsperger, S.

1983-01-01

440

Effect of potassium magnesium chloride in the fertigation solution as partial source of potassium on growth, yield and quality of greenhouse tomato  

Microsoft Academic Search

The effect of partial replacement of KCl in the fertigation by KCl·MgCl2 on growth, yield and quality of greenhouse tomato (cv. Durinta) was studied in a soil-less system. Forty-seven days after planting (DAP), three treatment solutions were applied to the plants using different K sources: (1) KNO3, (2) KCl, and (3) KCl·MgCl2+KCl (25%:75% in terms of K supplied). In both

Bishnu P Chapagain; Zeev Wiesman

2004-01-01

441

Effects of Phosphoric Acid Concentration on Platinum Catalyst and Phosphoric Acid Hydrogen Pump Performance  

NASA Astrophysics Data System (ADS)

This work involves the study of the operational performance of phosphoric acid based electrochemical hydrogen pumps with a polybenzimidazole (PBI) electrolytic membrane. During characterization of these devices, the power consumption was found to be highly sensitive to the water vapor pressure in the supply gas stream which in turn affects the phosphoric acid concentration. The power requirement was 30 times higher when the supply gas stream was not humidified than when the supply gas stream was humidified. Upon testing of electrochemical hydrogen pumps over a range of supply gas water vapor pressures from 150 to 0.8 mmHg, it was found that the effective platinum catalyst area decreases as phosphoric acid concentration increases in response to declining supply gas vapor pressure. It was hypothesized that the decline in the effective platinum catalyst area was caused by the adsorption of a species from the electrolyte that increases in concentration with phosphoric acid concentration. Polyphosphoric acid species were such a species which increased in concentration as phosphoric acid concentration increased and as a result were hypothesized to be the species adsorbing on the platinum catalyst. Additional testing was conducted in an electrochemical half cell in which the effect of phosphoric acid concentration on the platinum surface area at a single electrode interface could be studied. Impedance spectroscopy and cyclic voltammetry (CV) testing was used to measure changes in exchange current and platinum surface area following the exposure of the electrode to electrolyte. Platinum surface coverage estimates from CV measurements were 60-87% at a phosphoric acid concentration of 76 wt% P2O5 (105 wt% H3PO 4) and near 100% coverage at 83.3 wt% P2O5 (115 wt% H3PO4). The exchange current for hydrogen oxidation and reduction on platinum decreased by a factor of 25 for 76 wt% P2O 5 and a factor of 1000 for 83.3 wt% P2O5 phosphoric acid concentration within 36 hours. A similar dependence of platinum surface coverage and exchange current on phosphoric acid concentration was observed during hydrogen pump testing over a range of supply gas vapor pressures. This work indicates that platinum catalyst activity declines sharply above a phosphoric acid concentration of 72.4 wt% P2O5 (100 wt% H3PO4) which causes a significant increase in hydrogen pump power consumption. To reduce power consumption, the hydrogen gas supplied to the hydrogen pump requires humidification to a vapor pressure of at least 55 mmHg. The addition of humidification to the supply gas stream adds complexity to a system incorporating a phosphoric acid hydrogen pump. The need to add humidification equipment to reduce phosphoric acid hydrogen pump power consumption may have a significant impact when such devices are applied to hydrogen separation applications including hydrogen recovery from industrial exhaust streams and for emerging alternative energy applications.

Buelte, Steve

442

Survival of microencapsulated probiotic Lactobacillus paracasei LBC-1e during manufacture of Mozzarella cheese and simulated gastric digestion.  

PubMed

An erythromycin-resistant strain of probiotic Lactobacillus paracasei ssp. paracasei LBC-1 (LBC-1e) was added to part-skim Mozzarella cheese in alginate-microencapsulated or free form at a level of 10(8) and 10(7)cfu/g, respectively. Survival of LBC-1e and total lactic acid bacteria (LAB) was investigated through the pasta filata process of cheese making (in which the cheese curd was heated to 55 °C and stretched in 70 °C-hot brine), followed by storage at 4 °C for 6 wk and simulated gastric and intestinal digestion. This included incubation in 0.1 M and 0.01 M HCl, 0.9 M H(3)PO(4), and a simulated intestinal juice consisting of pancreatin and bile salts in a pH 7.4 phosphate buffer. Some reductions were observed in both free and encapsulated LBC-1e during heating and stretching, with encapsulated LBC-1e surviving slightly better. Changes in total LAB losses during heating and stretching did not reach statistical significance. During storage, a decrease was observed in total LAB, but no statistically significant decrease was observed in LBC-1e. Survival during gastric digestion in HCl was dependent on the extent of neutralization of HCl by the cheese, with more survival in the weaker acid, in which pH increased to 4.4 after cheese addition. The alginate microcapsules did not provide any protection against the HCl. It is interesting that survival of the encapsulated LBC-1e was greater during incubation in H(3)PO(4) than in the HCl gastric juices. Proper selection of simulated gastric digestion media is important for predicting the delivery of probiotic bacteria into the human intestinal tract. Neither free nor encapsulated LBC-1e was affected by incubation in the pancreatin-bile solution. Based on the level of probiotic bacteria in cheese needed to provide a health benefit and its survival during simulated gastric digestion, as determined in this study, it should theoretically be possible to lower the amount that needs to be ingested in cheese by up to a factor of 10(3) compared with other fermented dairy foods or when consumed as supplements. PMID:22981567

Ortakci, F; Broadbent, J R; McManus, W R; McMahon, D J

2012-11-01

443

??13C and ??18O isotopic composition of CaCo3 measured by continuous flow isotope ratio mass spectrometry: Statistical evaluation and verification by application to Devils Hole core DH-11 calcite  

USGS Publications Warehouse

A new method was developed to analyze the stable carbon and oxygen isotope ratios of small samples (400 ?? 20 ??g) of calcium carbonate. This new method streamlines the classical phosphoric acid/calcium carbonate (H3PO4/CaCO3) reaction method by making use of a recently available Thermoquest-Finnigan GasBench II preparation device and a Delta Plus XL continuous flow isotope ratio mass spectrometer. Conditions for which the H3PO4/CaCO3 reaction produced reproducible and accurate results with minimal error had to be determined. When the acid/carbonate reaction temperature was kept at 26??C and the reaction time was between 24 and 54 h, the precision of the carbon and oxygen isotope ratios for pooled samples from three reference standard materials was ???0.1 and ???0.2 per mill or %0, respectively, although later analysis showed that materials from one specific standard required reaction time between 34 and 54 h for ??18O to achieve this level of precision. Aliquot screening methods were shown to furthei minimize the total error. The accuracy and precision of the new method were analyzed and confirmed by statistical analysis. The utility of the method was verified by analyzing calcite from Devils Hole, Nevada, for which isotope-ratio values had previously been obtained by the classical method. Devils Hole core DH-11 recently had been re-cut and re-sampled, and isotope-ratio values were obtained using the new method. The results were comparable with those obtained by the classical method with correlation = +0.96 for both isotope ratios. The consistency of the isotopic results is such that an alignment offset could be identified in the re-sampled core material, and two cutting errors that occurred during re-sampling then were confirmed independently. This result indicates that the new method is a viable alternative to the classical reaction method. In particular, the new method requires less sample material permitting finer resolution and allows automation of some processes resulting in considerable time savings.

Revesz, K.M.; Landwehr, J.M.

2002-01-01

444

Sequential extraction method for determination of Fe(II/III) and U(IV/VI) in suspensions of iron-bearing phyllosilicates and uranium.  

PubMed

Iron-bearing phyllosilicates strongly influence the redox state and mobility of uranium because of their limited hydraulic conductivity, high specific surface area, and redox reactivity. Standard extraction procedures cannot be accurately applied for the determination of clay-Fe(II/III) and U(IV/VI) in clay mineral-U suspensions such that advanced spectroscopic techniques are required. Instead, we developed and validated a sequential extraction method for determination of clay-Fe(II/III) and U(IV/VI) in clay-U suspensions. In our so-called "H(3)PO(4)-HF-H(2)SO(4) sequential extraction" method, H(3)PO(4)-H(2)SO(4) is used first to solubilize and remove U, and the remaining clay pellet is subject to HF-H(2)SO(4) digestion. Physical separation of U and clay eliminates valence cycling between U(IV/VI) and clay-Fe(II/III) that otherwise occurred in the extraction solutions and caused analytical discrepancies. We further developed an "automated anoxic KPA" method to measure soluble U(VI) and total U (calculate U(IV) by difference) and modified the conventional HF-H(2)SO(4) digestion method to eliminate a series of time-consuming weighing steps. We measured the kinetics of uraninite oxidation by nontronite using this sequential extraction method and anoxic KPA method and measured a stoichiometric ratio of 2.19 ± 0.05 mol clay-Fe(II) produced per mol U(VI) produced (theoretical value of 2.0). We found that we were able to recover 98.0-98.5% of the clay Fe and 98.1-98.5% of the U through the sequential extractions. Compared to the theoretical stoichiometric ratio of 2.0, the parallel extractions of 0.5 M HCl for clay-Fe(II) and 1 M NaHCO(3) for U(VI) leached two-times more Fe(II) than U(VI). The parallel extractions of HF-H(2)SO(4) for clay Fe(II) and 1 M NaHCO(3) for U(VI) leached six-times more Fe(II) than U(VI). PMID:23075386

Luan, Fubo; Burgos, William D

2012-11-01

445

New solvent systems for gradient counter-current chromatography in separation of betanin and its derivatives from processed Beta vulgaris L. juice.  

PubMed

Betalains, natural plant pigments, are beneficial compounds due to their antioxidant and possible chemoprotective properties. A mixture of betalains: betanin/isobetanin, decarboxybetanins and neobetanin from processed red beet roots (Beta vulgaris L.) juice was separated in food-grade, gradient solvent systems using high-performance counter-current chromatography (HPCCC). The decarboxylated and dehydrogenated betanins were obtained by thermal degradation of betanin/isobetanin from processed B. vulgaris L. juice under mild conditions. Two solvent systems (differing in their composition by phosphoric acid and ethanol volume gradient) consisting of BuOH-EtOH-NaClsolution-H2O-H3PO4 (v/v/v/v/v, 1300:200-1000:1300:700:2.5-10) in the 'tail-to-head' mode were run. The flow rate of the mobile phase (organic phase) was 1.0 or 2.0ml/min and the column rotation speed was 1600rpm (20°C). The retention of the solvent system stationary phase (aqueous phase) was ca. 80%. The system with the acid and ethanol volume gradient consisting of BuOH-EtOH-NaClsolution-H2O-H3PO4 (v/v/v/v/v, 1300:200-240:1300:700:2.5-4.5) pumped at 2.0ml/min was the most effective for a separation of betanin/isobetanin, 17-decarboxy-betanin/-isobetanin, 2-decarboxy-betanin/-isobetanin, 2,17-bidecarboxy-betanin/-isobetanin pairs as well as neobetanin. The pigments were detected by LC-DAD and LC-MS. The results are crucial in the application of completely food-grade solvent systems in separation of food-grade compounds as well, and the systems can possibly be extended to other ionizable and polar compounds with potential health benefits. In particular, the method is applicable for the isolation and purification of betalains present in such rich sources as B. vulgaris L. roots as well as cacti fruits and Amaranthaceae flowering plants due to modification possibilities of the solvent systems polarity. PMID:25595533

Spórna-Kucab, Aneta; Garrard, Ian; Ignatova, Svetlana; Wybraniec, S?awomir

2015-02-01

446

Measurement of delta13C and delta18O Isotopic Ratios of CaCO3 by a Thermoquest Finnigan GasBench II Delta Plus XL Continous Flow Isotope Ratio Mass Spectrometer with Application to Devils Hole Core DH-11 Calcite  

USGS Publications Warehouse

A new method was developed to analyze the stable carbon and oxygen isotope ratios of small samples (400?20 ?g) of calcium carbonate. This new method streamlines the classical phosphoric acid - calcium carbonate (H3PO4 - CaCO3) reaction method by making use of a Thermoquest-Finnigan GasBench II preparation device and a Delta Plus XL continuous flow isotope ratio mass spectrometer. To obtain reproducible and accurate results, optimal conditions for the H3PO4 - CaCO3 reaction had to be determined. At the acid-carbonate reaction temperature suggested by the equipment manufacturer, the oxygen isotope ratio results were unsatisfactory (standard deviation () greater than 1.5 per mill), probably because of a secondary reaction. When the acid-carbonate reaction temperature was lowered to 26?C and the reaction time was increased to 24 hours, the precision of the carbon and oxygen isotope ratios for duplicate analyses improved to 0.1 and 0.2 per mill, respectively. The method was tested by analyzing calcite from Devils Hole, Nevada, which was formed by precipitation from ground water onto the walls of a sub-aqueous cavern during the last 500,000 years. Isotope-ratio values previously had been obtained by the classical method for Devils Hole core DH-11. The DH-11 core had been recently re-sampled, and isotope-ratio values were obtained using this new method. The results were comparable to those obtained by the classical method. The consistency of the isotopic results is such that an alignment offset could be identified in the re-sampled core material, a cutting error that was then independently confirmed. The reproducibility of the isotopic values is demonstrated by a correlation of approximately 0.96 for both isotopes, after correcting for an alignment offset. This result indicates that the new method is a viable alternative to the classical method. In particular, the new method requires less sample material permitting finer resolution and allows automation of some processes resulting in considerable timesavings.

Revesz, Kinga M.; Landwehr, Jurate Maciunas; Keybl, Jaroslav Edward

2001-01-01

447

Presence of phosphorus in Nephila clavipes dragline silk.  

PubMed Central

Solid-state 31P-NMR of Nephila clavipes dragline silk indicates the presence of phosphorus in at least two chemically distinct environments. Amino acid analyses of acid-hydrolyzed silk confirm the presence of phosphotyrosine as one of the phosphorus-containing components. The unusual chemical shift (18.9 ppm downfield from 85% H3PO4), proton chemical shift, and acid lability of a second component suggest that it is part of a strained five-membered cyclic phosphate that might be found on a beta-D-ribose. The five-membered cyclic phosphate is not removed from the silk fibers by exhaustive aqueous extraction. It is absent in nascent silk fibroin from the glands, suggesting that its formation is part of the fiber processing that occurs in the ducts leading to the spinnerets. High-resolution NMR spectra of silk dissolved in propionic acid/12 N HCl (50:50 v/v) show five phosphorus sites assigned to phosphorylated tyrosine residues, phosphorylated serine residues, inorganic phosphate, and two hydrolysis products of the cyclic phosphate compound. The observed posttranslational phosphorylation may be important in the processing and modulation of the physical properties of dragline silk. PMID:8770226

Michal, C A; Simmons, A H; Chew, B G; Zax, D B; Jelinski, L W

1996-01-01

448

In-situ monitoring of the dielectric and electrostrictive properties of anodised thin films for biochip applications.  

PubMed

Further improving the performance of capacitance-based DNA microsensors will depend on the ability to synthesize simply, at a low cost, thin films of high dielectric permittivity with a well-controlled growth morphology. Anodisation of the valve metals Ti, Zr and Ta is a promising route for preparing such films. In this paper, we propose a new method for following the evolution of the dielectric properties of such anodised metallic oxide thin films in-situ during their growth. The technique relies on measuring the evolution of the electrostatic stress developing in the film. Measurements have been carried out on anodic TiO(2) films grown galvanostatically in HNO(3) at 1 and 3 mA/cm(2) and in H(3)PO(4) at 0.5 mA/cm(2). The dielectric permittivity of the films was observed to decrease during the initial stage of anodisation, characterised by a steady increase of the cell voltage with time. The permittivity then reached a constant value when the oxide entered a second growth regime, characterised by a stabilisation of the cell voltage. The origin of the observed permittivity evolution is interpreted in terms of the evolution of the growth morphology of the films during anodisation. PMID:17142021

Vanhumbeeck, J-F; Proost, J

2007-04-15

449

Electrochemical oxide nanotube formation on the Ti-35Ta-xHf alloys for dental materials.  

PubMed

In this study, we investigated the electrochemical oxide nanotube formation on the Ti-35Ta-xHf alloys for dental materials. The Ti-35Ta-xHf alloys contained from 3 wt.% to 15 wt.% Hf were manufactured by arc melting furnace. The nanotube oxide layers were formed on Ti-35Ta-xHf alloy by anodic oxidation method in 1 M H3PO4 electrolytes containing 0.5 wt.% NaF and 0.8 wt.% NaF at room temperature. The surface characteristics of Ti-35Ta-xHf alloy and nanotube morphology were determined by FE-SEM, STEM, and XRD. The nano-porous surface of Ti-35Ta-xHf alloys showed in 0.5 wt% NaF solution and nanotubular surface showed in 0.8 wt% NaF solution, respectively. The highly ordered nanotube layer without regular knots was formed on the Ti-35Ta-15Hf alloy in the 0.5 wt% NaF solution compared to on Ti-35Ta-3Hf and Ti-35Ta-7Hf alloys in 0.8 wt% NaF solution. Also, the nanotube length of Ti-35Ta-xHf alloys increased as Hf content increased. PMID:22103212

Moon, Byung-Hak; Jeong, Yong-Hoon; Choe, Han-Cheol

2011-08-01

450