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1

Oscillation in the Kmno 4?NH 2CH 2COOH?H 3PO 4 Cstr system  

NASA Astrophysics Data System (ADS)

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

Li, Hexing; Huang, Xiaojun; Deng, Jingfa

1996-08-01

2

Preparation and characterization of activated carbon from reedy grass leaves by chemical activation with H3PO4  

NASA Astrophysics Data System (ADS)

Activated carbons were produced from reedy grass leaves by chemical activation with H3PO4 in N2 atmosphere and their characteristics were investigated. The effects of activation temperature and time were examined. Adsorption capacity was demonstrated with BET and iodine number. Micropore volume and pore size distribution of activated carbons were characterized by N2 adsorption isotherms. The surface area and iodine number of the activated carbons produced at 500 °C for 2 h were 1474 m2/g and 1128 mg/g, respectively. Thermal decomposition of pure reedy grass leaves and H3PO4-impregnated reedy grass leaves have been investigated with thermogravimetric/mass spectroscopy (TG-MS) technique. It was found that the temperature and intensity of maximum evolution of H2O and CO2 of H3PO4-impregnated reedy grass leaves were lower than that of pure reedy grass leaves. This implies that H3PO4 as an activating reagent changed the thermal degradation of the reedy grass leaves, stabilized the cellulose structure, leading to a subsequent change in the evolution of porosity. The results of X-ray photoelectron spectroscopy and Fourier-infrared spectroscopy analysis indicate that the produced activated carbons have rich functional groups on surface.

Xu, Jianzhong; Chen, Lingzhi; Qu, Hongqiang; Jiao, Yunhong; Xie, Jixing; Xing, Guangen

2014-11-01

3

A study of rosemary oil as a green corrosion inhibitor for steel in 2 M H3PO4  

Microsoft Academic Search

Purpose – To evaluate the effect of natural rosemary oil as non toxic inhibitor on the corrosion of steel in H3PO4 media at various temperatures. Design\\/methodology\\/approach – The oil was hydro-distilled. The oil was used as inhibitor in various corrosion tests. Gravimetric and electrochemical techniques were used to characterise the corrosion mechanism. Findings – Chromatographic analysis by GC showed that

M. Bendahou; M. Benabdellah; B. Hammouti

2006-01-01

4

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

5

Systematic characterization of a PBI\\/H 3PO 4 sol–gel membrane—Modeling and simulation  

Microsoft Academic Search

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

C. Siegel; G. Bandlamudi; A. Heinzel

2011-01-01

6

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

7

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

PubMed Central

Background A new and efficient method have been developed for the synthesis of different indole derivatives from various ketones, having at least one hydrogen atom attached to each of their ?-carbon atoms, and hydrazines in solvent-free conditions, using marine sponge/H3PO4 as a naturally occurring chiral catalyst. Objectives This study recommended the use of marine sponge/H3PO4 as a naturally occurring chiral catalyst for preparation of phenylhydrazones from ketones having one ?-hydrogen and subsequent cyclisation of the products to indoles. Materials and Methods The reaction was carried out by mixing the phenylhydrazine, ketone, and marine sponge/H3PO4 powder in mortar and pestle; the mixture was ground at room temperature in an appropriate time until TLC show the completion of the reaction. The product extracted by CH2Cl2 and evaporation of solvent yields the products. Results In this research work, several indoles are synthesized using phenylhydrazine and aliphatic or aromatic ketone as starting materials, in the presence of marine sponge/H3PO4 powder as a natural catalyst under solvent-free condition. Conclusions We found marine sponge/H3PO4 to be an effective catalyst for indolisation of phenylhydrazones from ketones having ?-hydrogens in solvent-free conditions. PMID:24624207

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

2013-01-01

8

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

9

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

PubMed

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

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

2008-08-15

10

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

11

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

12

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

13

Inhibition de la corrosion d'acier au carbone en milieu H3PO4 2M par des composés organiques de type ``triazine''  

NASA Astrophysics Data System (ADS)

The effect of addition of some triazine compounds on the corrosion behaviour of steel in 2M H3PO4 has been studied by weight loss and electrochemical polarisation methods. Both methods showed that the dissolution rate was dependent on the chemical properties and concentration of the product. From comparison of results, it was found that 6-azathymine (T6) is the best inhibitor and its inhibition efficiency reaches a maximum value of 86% at 10-3 M. Polarisation measurements indicated that T6 acts as cathodic inhibitor by merely blocking the reaction sites without changing the mechanism of the hydrogen evolution reaction. It was found that T6 was adsorbed on steel surface according to a Langmuir isotherm model. The effect of temperature indicated that inhibition efficiency of T6 is dependent on the temperature in the range 25-50 circC. L'effet de l'addition de certains composés organiques de type triazine sur la corrosion d'un acier en milieu H3PO4 2M a été étudié à l'aide des méthodes électrochimiques et gravimétriques. Les résultats obtenus ont montré que la vitesse de dissolution de l'acier dépend de la structure moléculaire et de la concentration du produit. La comparaison des efficacités inhibitrices montre que le 6-azathymine (T6) est le meilleur inhibiteur de la série des triazines testés. L'efficacité inhibitrice du T6 atteint une valeur maximale de 86 % à 10-3 M. L'allure des courbes de polarisation indique que le T6 agit essentiellement comme inhibiteur de type cathodique par adsorption à la surface de l'acier selon le modèle de l'isotherme de Langmuir. L'efficacité inhibitrice du T6 dépend de la température dans le domaine allant de 25 à 50 circC.

Bekkouch, K.; Aouniti, A.; Hammouti, B.; Kertit, S.

1999-05-01

14

Surface passivation of MgAl2O4 spinel powder by chemisorbing H3PO4 for easy aqueous processing.  

PubMed

A stoichiometric MgAl 2O 4 spinel (MAS) powder was synthesized by heat treating at 1400 degrees C for 2 h a compacted mixture of alpha-Al 2O 3 and calcined caustic MgO, followed by crushing and milling. The surface of this powder was then passivated against hydrolysis with H 3PO 4 and Al(H 2PO 4) 3 in an ethanol solution. The as-passivated powder could then be dispersed in water using tetramethylammonium hydroxide (TMAH) and an ammonium salt of poly(acrylic acid) (Duramax D-3005) as dispersing agents and gelcast to form green consolidates with relatively high strength (>15 MPa). The good dispersing behavior of the passivated powder in water was confirmed by the low viscosity of its suspension containing 41-45 vol % solids, demonstrating the viability of replacing organic solvents by water in colloidal processing of MAS-based ceramics. The Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and energy dispersive X-ray (EDAX) studies revealed that only negligible amounts of phosphate ions at the surface are required to effectively protect the powder from reacting with water. PMID:18671420

Olhero, Susana M; Ganesh, Ibram; Torres, Paula M C; Ferreira, José M F

2008-09-01

15

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

PubMed

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

Birnhack, Liat; Sabach, Sara; Lahav, Ori

2012-10-15

16

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

17

Characterization and lead adsorption properties of activated carbons prepared from cotton stalk by one-step H3PO4 activation.  

PubMed

Activated carbons were prepared from cotton stalk by one-step H(3)PO(4) activation and used as adsorbent for the removal of lead(II). Taguchi experimental design method was used to optimize the preparation of the adsorbents. The results showed that the optimized conditions were: impregnation with a 50% (w/v) phosphoric acid solution with a mass ratio of 3:2 and activation temperature at 500 degrees C for 60 min with the rate of achieving the activation temperature equal to 10 degrees C min(-1). The cotton stalk activated carbon (CSAC) prepared at these conditions have 1.43 mmol g(-1) acidic surface groups and 1570 m(2) g(-1) BET surface area. Adsorption isotherms for lead(II) on the adsorbents were measured by conducting a series of batch adsorption experiments. The Langmuir maximum adsorption amount of lead(II) on CSAC was more than 119 mg g(-1), which was superior to the ordinary commercial activated carbon (CAC) on the market. Compared with the CAC, the CSAC had a wider applicable pH range from 3.5 to 6.5 for lead(II) uptake. The final pH values at equilibrium after adsorption were lower than the initial pH value, indicating that the ion-exchange process was involved in the adsorption. This is also confirmed by the result that the increase of acidic surface groups favored the adsorption process. Thermodynamic study indicated that the adsorption was a spontaneous and endothermic process. PMID:20542631

Li, Kunquan; Zheng, Zheng; Li, Ye

2010-09-15

18

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

NASA Technical Reports Server (NTRS)

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

Pellett, Gerald

2005-01-01

19

Synthesis, molecular structure, and characterization of a new 3D-layered inorganic–organic hybrid material: [ d\\/ lC 6H 13O 2N–H] 3[(PO 4)W 12O 36]·4.5H 2O  

Microsoft Academic Search

A new 3D-layered inorganic–organic hybrid [d\\/l-C6H13O2N–H]3[(PO4)W12O36]·4.5H2O (1), as racemic material in the solid phase, has been synthesized and fully characterized by elemental microanalysis, single crystal X-ray diffraction, and infrared, Raman, and proton nuclear magnetic resonance spectroscopes. The most unique structural feature of 1 is its three-dimensional inorganic infinite tunnel-like framework that results in weak van der Waals interactions along the

Mohammad H. Alizadeh; Masoud Mirzaei; Ali R. Salimi; Hossein Razavi

2009-01-01

20

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

NASA Astrophysics Data System (ADS)

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

Perez-Davis, Marla E.; Difilipo, Frank

1990-06-01

21

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

NASA Technical Reports Server (NTRS)

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

Perez-Davis, Marla E.; Difilipo, Frank

1990-01-01

22

The Elastic Properties of Natural Portlandite Ca(OH)2  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

23

Effect of ZnO nanomaterials associated with Ca(OH) 2 as anode material for Ni–Zn batteries  

Microsoft Academic Search

Prism ZnO nanomaterials coated with Ca(OH)2 were prepared by direct precipitation. TEM micrographs showed that dendritic Ca(OH)2 seemed to attach on the surface of nanosized ZnO. The XRD patterns indicated that the coating was Ca(OH)2·2Zn(OH)2·2H2O. The nanosized ZnO coated with Ca(OH)2 as the anode materials were investigated by the charge–discharge cycle measurement and EIS. The combination of ZnO nanomaterials and

Y. F. Yuan; J. P. Tu; H. M. Wu; Y. Li; D. Q. Shi; X. B. Zhao

2006-01-01

24

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

25

The enthalpy of transformation of Ca(OH)2-I (portlandite) to Ca(OH)2-II (EuI2 structure) by low-temperature DSC  

NASA Astrophysics Data System (ADS)

Thermodynamic properties of high-pressure minerals that are not recoverable from synthesis experiments by conventional quenching methods (``unquenchable'' phases) usually are calculated from equation of state data and phase diagram topologies. The present study shows that, with cryogenic methods of recovery and sample treatment, phases with a suitable decomposition rate can be made accessible to direct thermodynamic measurements. A set of samples of Ca(OH)2-II has been synthesized in a multianvil device and subsequently recovered by cooling the high-pressure assembly with liquid nitrogen. Upon heating from liquid nitrogen to room temperature, the material transformed back to Ca(OH)2-I. The heat effect of this backtransformation was measured by differential scanning calorimetry. A commercial differential scanning calorimeter (Netzsch DSC 404), modified to allow sample loading at liquid nitrogen temperature was used to heat the material from -150 to +200°C at rates varying between 5 and 15°Cmin-1. The transformation started around -50°C very gradually, and peaked at about 0°C. To obtain a baseline correction, each sample was scanned under exactly the same conditions after the backtransformation was complete. Because of the relative sluggishness, onset and offset temperatures were not well defined as compared to fast (e.g., melting) reactions. To aid in integration, the resulting signals were successfully fitted using a generic asymmetric peak model. The enthalpy of backtransformation was determined to be ?H=-10.37+/-0.50kJ mol-1. From previous in situ X-ray diffraction experiments, the location of the direct transformation in P-T space has been constrained to 5.7+/-0.4GPa at 500°C (Kunz etal. 1996). With the reaction volume known from the same study, and assuming that ?Cp of the transformation remains negligible between the conditions of our measurements and 500°C, our result gives an estimate of the entropy of transition and the P-T slope of the reaction curve. To a first approximation, the values ?S=-16.00+/-0.65 J(mol.K)-1 and dP/dT=0.0040+/-0.0002GPa/K have been determined. These results need to be refined by equation of state data for Ca(OH)2-II.

Schoenitz, M.; Navrotsky, A.; Leinenweber, K.

26

Heat recovery from a thermal energy storage based on the Ca(OH) 2\\/CaO cycle  

Microsoft Academic Search

Thermal energy storage is very important in many applications related to the use of waste heat from industrial processes, renewable energies or from other sources. Thermochemical storage is very interesting for long-term storage as it can be carried out at room temperature with no energy losses.Dehydration\\/hydration cycle of Ca(OH)2\\/CaO has been applied for thermal energy storage in two types of

M. N. Azpiazu; J. M. Morquillas; A. Vazquez

2003-01-01

27

Pore structures of fly ashes activated by Ca(OH) 2 and CaSO 4 · 2H 2O  

Microsoft Academic Search

The nature of the pore structure which develops when low-lime fly ash reacts with Ca(OH)2 and CaSO4 · 2H2O under hydrothermal treatment has been investigated. The nitrogen adsorption-desorption isotherms of hydrothermally treated samples of fly ash and activated fly ash were analyzed. X-ray diffractometry was used to characterize the hydration products and SEM was used to analyze microstructure. The shapes

Weiping Ma; Chunling Liu; Paul W. Brown; Sridhar Komarneni

1995-01-01

28

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

29

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

NASA Technical Reports Server (NTRS)

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

Meade, Charles; Jeanloz, Raymond

1990-01-01

30

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

31

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

Microsoft Academic Search

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

Marit Jagtoyen; Frank Derbyshire

1998-01-01

32

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

Microsoft Academic Search

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

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

1996-01-01

33

Pilot scale demonstration of D-lactic acid fermentation facilitated by Ca(OH)2 using a metabolically engineered Escherichia coli.  

PubMed

In this study, a genetically engineered Escherichia coli strain, HBUT-D (?pflB ?pta ?frdABCD ?adhE ?ald ?cscR), was initially evaluated on a laboratory scale (7 L) in a glucose (130 g L(-1)) mineral salts medium for d-lactic acid fermentation using 6N KOH, Ca(OH)2 or NH4OH as the neutralizing agent. Fermentations neutralized by Ca(OH) 2 achieved a volumetric productivity of 6.35 g L(-1) h(-1), tripling that achieved by KOH (1.71 g L(-1) h(-1)) and NH4OH (1.5 g L(-1) h(-1)). The facilitative effect of Ca(OH)2 neutralization was then demonstrated on a pilot scale (6 ton vessel, 130 kg glucose ton(-1)), resulting in a volumetric productivity of 6 kg ton(-1) h(-1), a titer of 126 kg ton(-1), a yield of 97%, and an optical purity of 99.5%. These results demonstrated that E. coli HBUT-D is a promising strain for large scale d-lactic acid fermentation using mineral salts medium and Ca(OH)2 for neutralization. PMID:25103032

Liu, Ye; Gao, Wa; Zhao, Xiao; Wang, Jinhua; Garza, Erin; Manow, Ryan; Zhou, Shengde

2014-10-01

34

Solubility of niobium in the system CaCO3-Ca(OH)2-NaNbO3 at 0.1 GPa pressure  

NASA Astrophysics Data System (ADS)

Experimental data are presented for the solubility of NaNbO3 in the ternary system CaCO3-Ca(OH)2-NaNbO3 (or calcite-portlandite-lueshite) over the temperature range 500-950 °C at 0.1 GPa pressure. Near-liquidus phase relationships are given for the pseudo-binary join ([CaCO3]45[Ca(OH)2]55)100-x-(NaNbO3)x (0

Mitchell, Roger; Kjarsgaard, Bruce

2002-08-01

35

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

PubMed

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

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

2002-12-01

36

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

Microsoft Academic Search

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

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

2011-01-01

37

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

38

Follow us on twitter @csi_kcl http://www.csi.kcl.ac.uk/mccresearch WHO Collaborating Centre  

E-print Network

MORECare Capacity - Mental capacity and processes of consent for research on end- of-life care Expert Think_kcl http://www.csi.kcl.ac.uk/mccresearch Why is research on end-of-life care important? Science in research on end-of-life care 2. To help understand the narrativ

Kühn, Reimer

39

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

Microsoft Academic Search

It is stated that all the synthetic carbonate-hydroxyapatites, produced with the reaction of H3PO4 and Ca(OH)2 solutions, are B type carbonate-apatites. The carbonate content of these is completely eliminated up to 900 C. In dental enamels taken from\\u000a the healthy teeth of females, the carbonate ions occupy different positions (A–B type carbonate-apatite). Those which are parallel to axis c are

K. Jdnfis; I. Vassfinyi; I. Ungvfiri

1980-01-01

40

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

Microsoft Academic Search

It is stated that all the synthetic carbonate-hydroxyapatites, produced with the reaction of H3PO4 and Ca(OH)2 solutions, are B type carbonate-apatites. The carbonate content of these is completely eliminated up to 900° C. In dental enamels taken from the healthy teeth of females, the carbonate ions occupy different positions ( A B type carbonate-apatite). Those which are parallel to axis

K. Jónás; I. Vassányi; I. Ungvári

1980-01-01

41

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

NASA Astrophysics Data System (ADS)

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

Nara, Jun-ichi; Adachi, Sadao

2011-12-01

42

K-Cl cotransport: properties and molecular mechanism.  

PubMed

K-Cl cotransport (COT), defined first in red blood cells as the Cl-dependent, ouabain-insensitive bidirectional K transport, encoded by at least four KCC (kalium-chloride-cotransport) genes, is now recognized as a functional and structural reality in all cell membranes. As functional system, K-Cl COT is necessary for volume and ionic homeostasis. Since its original discovery by swelling red cells in hyposmotic solutions and by treatment with N-ethylmaleimide (NEM), K-Cl COT has been recognized as one of the prime electroneutral, low ion affinity pathways effecting regulatory volume decrease (RVD). This review first summarizes the general properties of K-Cl COT, including ion dependence, kinetics, thermodynamics and regulation in erythrocytes of various species, and then focuses on the newest findings of the molecular mechanisms behind K-Cl COT, the KCC isoforms and their expression in epithelial cells and in Xenopus oocytes. Based on early biophysical studies on red cells amalgamated with the recent molecular expression studies of the four KCC isoforms, K-Cl COT emerges as one of the oldest membrane transporters that is controlled by a complex redox-dependent cascade of kinases and phosphatases, yet to be defined at the molecular level. Whereas RVD is a primeval role of K-Cl COT for survival of cells challenged by hyposmotic environments, maintenance of intracellular Cl ([Cl](I) ) levels away from electrochemical equilibrium and K buffering capability during neuronal function are new additions to the list of physiological functions of this system. PMID:11125215

Lauf, P K; Adragna, N C

2000-01-01

43

Combinatorial Mathematicians based in Britain. Abdullah, M. KCL  

E-print Network

-Seraji, Najm Sussex Al-Zengana, Emad Sussex Anderson, Dr. Ian Glasgow Anthony, Prof. Martin LSE Appa, Prof. G Cooley, J. RHUL Cooper, Dr. Colin KCL Cooper, Prof. S. Barry Leeds Cosh, Ben Reading Crampton, Dr. Jason. Newcastle Dyer, Prof. Martin Leeds Dzamonja, Dr. Mirna UEA E #12;Edwards, Dr. Keith J. Dundee Eleftheriou

44

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.

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

2014-10-01

45

Hydrothermal synthesis of an open-framework manganese oxalate incorporating KCl chains  

Microsoft Academic Search

A manganese oxalate of the composition, K2[Mn2(C2O4)3]2[KCl]·2H2O, containing metal oxalate layers connected by monodentate oxalate units has been synthesized hydrothermally. An unique feature of this material is that it contains K?Cl chains with a K?Cl distance of ?3.2Å, close to the value in bulk KCl.

R. Vaidhyanathan; Srinivasan Natarajan; C. N. R. Rao

2003-01-01

46

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

47

Morphological and structural investigation of ?-sexithiophene grown on KCl (100)  

NASA Astrophysics Data System (ADS)

?-sexithiophene was deposited on KCl (100) by hot wall epitaxy technique at different substrate temperatures (60 °C 135 °C). The morphological investigation was performed by AFM and optical microscopy, revealing terraced islands and needle-like anisotropic structures. Structural investigations were performed by specular XRD scans. Upright standing molecules have been detected, which could be related to the terraced islands ((100) crystal contact plane). Furthermore, (010) and (-411) crystal planes have been observed, which explains the observed nano-needles (flat lying molecules). The texture was investigated by XRD pole figures, showing that all three crystal types exhibit a well defined azimuthal alignment with respect to KCl high symmetry directions. Interestingly, the epitaxial orientation of the islands could be explained by ledge directed epitaxy, which describes the nucleation of crystallites on existing topographic features on the substrate (nano-needles). A real space model of the crystallites was developed with the help of XRD pole figures and single crystal data. Surprisingly, the azimuthal orientation of the long moleculear axis is exactly the same for needles with (010) and (-411) contact planes. This observation represents a hint that the adsorption geometry of single molecules seems to be decisive for the organic crystal nucleation. Additionally, the substrate surface symmetry is nicely reflected by the multiplicity of formed needle orientations.

Schwabegger, Günther; Djuric, Tatjana; Sitter, Helmut; Resel, Roland; Simbrunner, Clemens

2013-09-01

48

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

PubMed Central

Purpose: The low effective atomic number, reusability, and other computed radiography-related advantages make europium doped potassium chloride (KCl:Eu2+) a promising dosimetry material. The purpose of this study is to model KCl:Eu2+ point dosimeters with a Monte Carlo (MC) method and, using this model, to investigate the dose responses of two-dimensional (2D) KCl:Eu2+ storage phosphor films (SPFs). Methods: KCl:Eu2+ point dosimeters were irradiated using a 6 MV beam at four depths (5–20 cm) for each of five square field sizes (5×5–25×25 cm2). The dose measured by KCl:Eu2+ was compared to that measured by an ionization chamber to obtain the magnitude of energy dependent dose measurement artifact. The measurements were simulated using DOSXYZnrc with phase space files generated by BEAMnrcMP. Simulations were also performed for KCl:Eu2+ films with thicknesses ranging from 1 ?m to 1 mm. The work function of the prototype KCl:Eu2+ material was determined by comparing the sensitivity of a 150 ?m thick KCl:Eu2+ film to a commercial BaFBr0.85I0.15:Eu2+-based SPF with a known work function. The work function was then used to estimate the sensitivity of a 1 ?m thick KCl:Eu2+ film. Results: The simulated dose responses of prototype KCl:Eu2+ point dosimeters agree well with measurement data acquired by irradiating the dosimeters in the 6 MV beam with varying field size and depth. Furthermore, simulations with films demonstrate that an ultrathin KCl:Eu2+ film with thickness of the order of 1 ?m would have nearly water-equivalent dose response. The simulation results can be understood using classic cavity theories. Finally, preliminary experiments and theoretical calculations show that ultrathin KCl:Eu2+ film could provide excellent signal in a 1 cGy dose-to-water irradiation. Conclusions: In conclusion, the authors demonstrate that KCl:Eu2+-based dosimeters can be accurately modeled by a MC method and that 2D KCl:Eu2+ films of the order of 1 ?m thick would have minimal energy dependence. The data support the future research and development of a KCl:Eu2+ storage phosphor-based system for quantitative, high-resolution multidimensional radiation therapy dosimetry. PMID:20175476

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

2010-01-01

49

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

Microsoft Academic Search

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

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

2010-01-01

50

H 2 O activity in concentrated KCl and KCl-NaCl solutions at high temperatures and pressures measured by the brucite-periclase equilibrium  

Microsoft Academic Search

H2O activities in supercritical fluids in the system KCl-H2O-(MgO) were measured at pressures of 1, 2, 4, 7, 10 and 15? kbar by numerous reversals of vapor compositions in equilibrium\\u000a with brucite and periclase. Measurements spanned the range 550–900?°C. A change of state of solute KCl occurs as pressures\\u000a increase above 2?kbar, by which H2O activity becomes very low and,

L. Y. Aranovich; R. C. Newton

1997-01-01

51

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

Microsoft Academic Search

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

Toshihiko Kataoka; Teruyoshi Uematsu; Tomoharu Yamada

1978-01-01

52

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

53

Electron stimulated desorption of neutral species from (100) KCl surfaces  

NASA Astrophysics Data System (ADS)

Composition changes of a (100) KCl surface bombarded by 1 keV electrons have been studied by Auger electron spectroscopy. Intensity ratios of characteristic alkali and halogen Auger lines were monitored as a function of target temperature and beam current density. In addition, for the first time angle-resolved energy distributions of electron desorbed K and Cl atoms were measured using mass-analyzed time of flight techniques. For temperatures higher than about 100°C, a near-stoichiometric surface composition was obtained and a significant non-thermal component was observed in the kinetic energy distributions of Cl atoms emitted normal to the (100) surface. These results can be interpreted in terms of new concepts regarding the excitonic mechanism of electron stimulated desorption (ESD).

Szymonski, M.; Poradzisz, A.; Czuba, P.; Kolodziej, J.; Piatkowski, P.; Fine, J.; Tanovic, L.; Tanovic, N.

1992-01-01

54

In-plane alignment of para-sexiphenyl films grown on KCl(0 0 1)  

NASA Astrophysics Data System (ADS)

The three-dimensional growth of para-sexiphenyl (p-6P) on KCl(0 0 1) is characterized by a large polymorphism. Using grazing-incidence diffraction, we have found that two of the known five orientational phases feature preferential in-plane alignments along the [1 1 0] in-plane direction of the substrate: p-6P(1 1 -1) ? KCl(0 0 1) with [1 -1 0] ? KCl[1 1 0] as well as p-6P(0 0 1) ? KCl(0 0 1) with [1 -1 0] ? KCl[1 1 0]. The latter structure is a peculiar low-symmetry configuration, which can be understood by analysis of the molecular crystal lattice and the substrate symmetry.

Smilgies, Detlef-M.; Boudet, Nathalie; Yanagi, Hisao

2002-04-01

55

Vacancy Dipole Currents of Thermostimulated Depolarization in a Plastically Deformed KCl Crystal  

NASA Astrophysics Data System (ADS)

A thermostimulated depolarization current of divacancies ( ? {/c -} ? {/a +}) created due to plastic deformation of a KCl crystal is detected. The thermostimulated depolarization current with a maximum at 205 K is correlated with the increasing degree of relative deformation of the KCl crystal. The mechanism of effective formation of (Cl{3/-}) aca centers is interpreted as a result of interaction of two mobile interstitial halogen atoms in the field of divacancies ( ? {/c -} ? {/a +}).

Shunkeyev, K. Sh.; Sergeyev, D. M.; Myasnikova, L. N.; Barmina, A. A.; Zhanturina, N. N.; Shunkeyev, S. K.; Aimaganbetova, Z. K.

2014-08-01

56

Ultrasonic velocity, attenuation, and nonlinearity constant in pure and Cd-doped KCl  

Microsoft Academic Search

Single crystals of pure and Cd-doped KCl (1000 ppm) were grown by the Czochralski technique. The acoustic attenuation and velocity in pure and Cd-doped KCl for the longitudinal waves along the [100] direction at 12 MHz are measured by single-ended pulse-echo and pulse-echo-overlap methods in the temperature range 173-303 K. The acoustic attenuation is measured in the frequency range 12-228

D. N. Joharapurkar; S. Rajagopalan; B. K. Basu

1988-01-01

57

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

58

Vacuum evaporation of KCl-NaCl salts: Part I. thermodynamic modeling of vapor pressures of solid and liquid solutions  

Microsoft Academic Search

In electrorefining to purify plutonium scraps and alloys, typically an equal molar KCl-NaCl mixture is used as the molten electrolyte through which the oxidized Pu ions are transported to the cathode where the pure plutonium is produced and settles by gravity to the bottom of the molten salt. In molten salt extraction, molten KCl-NaCl salt or KCl-NaCl salt containing MgClâ

Lily L. Wang; Terry C. Wallace

1996-01-01

59

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

60

Ultrasonic velocity, attenuation, and nonlinearity constant in pure and Cd-doped KCl  

NASA Astrophysics Data System (ADS)

Single crystals of pure and Cd-doped KCl (1000 ppm) were grown by the Czochralski technique. The acoustic attenuation and velocity in pure and Cd-doped KCl for the longitudinal waves along the [100] direction at 12 MHz are measured by single-ended pulse-echo and pulse-echo-overlap methods in the temperature range 173-303 K. The acoustic attenuation is measured in the frequency range 12-228 MHz at room temperature (303 K). The Cd-doped KCl sample showed an increase in attenuation and a decrease in velocity compared to the pure sample. We have also estimated Mason's nonlinearity constant D along the [100] direction at 303 K from the second-order elastic and third-order elastic constants and furthermore used it to evaluate the ultrasonic attenuation in the frequency range 12-228 MHz. These values are compared with our measured attenuation values.

Joharapurkar, D. N.; Rajagopalan, S.; Basu, B. K.

1988-02-01

61

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

NASA Astrophysics Data System (ADS)

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

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

2000-11-01

62

Mathematical modeling of LiAl/LiCl,KCl/FeS cells  

NASA Astrophysics Data System (ADS)

The thermodynamic equlibrium behavior and nonequilibrium behavior of high-temperature LiAl/LiCl,KCl/FeS cells are investigated. Results are presented for LiK6Fe24S26 as the intermediate discharge product of the FeS electrode. The model is used to predict cell potential and electrolyte composition changes throughout the cell as a function of discharge state, and it shows that the clogging of pores by KCl precipitation can limit the utilization of the FeS electrode during discharge.

Bernardi, Dawn; Pawlikowski, Ellen M.; Newman, John

1988-12-01

63

Off-center position of the Li+ ion in the FA center in KCl  

NASA Astrophysics Data System (ADS)

The photostimulated reorientation of FA centers in KCl: Li+ is affected by the off-axis geometry of the dipoles and by the overlap between the FA1 and FA2 absorption bands at each pumping wavelength. A detailed model of such a process, so far successfully compared to experimental results of optical absorption and emission in stationary equilibrium conditions, has been applied to studies of transient effects. The results further confirm the value of the off-axis angle of FA (Li) centers in KCl.

Baldacchini, G.; Grassano, U. M.; Scacco, A.; Somma, F.

1988-03-01

64

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

SciTech Connect

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

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

2010-01-15

65

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

NASA Technical Reports Server (NTRS)

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

Holleck, G. L.

1971-01-01

66

Temperature Gradient Induced Migration of Gas-Filled Bubbles in KCl  

Microsoft Academic Search

The temperature gradient induced migration of gas bubbles has been studied in KCl. This material was selected because of its high vapor pressure and transparency. The experimental variables of temperature, temperature gradient, and diffusion coefficient of the vapor species were investigated and the observed velocities were shown to agree with those expected from the theoretically derived model. The ratio of

R. E. Carter; J. H. Rosolowski; J. S. Nadeau

1971-01-01

67

Yield Strength and Dislocation Mobility of KCl-KBr Solid Solution Single Crystals  

Microsoft Academic Search

The concentration and strain rate dependence of the critical shear stress in KCl-KBr solid solutions was measured by compression tests. These data were compared with the stress dependence of the dislocation velocity measured by an etch pit technique. Edge dislocation moved slower than screw dislocation at the same stress level. The critical stress was determined by the edge dislocation mobility,

Toshihiko Kataoka; Tomoharu Yamada

1977-01-01

68

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

PubMed Central

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

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

2013-01-01

69

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

70

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

PubMed

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

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

2013-09-01

71

Calcium-independent phospholipase A2 participates in KCl-induced calcium sensitization of vascular smooth muscle.  

PubMed

In vascular smooth muscle, KCl not only elevates intracellular free Ca(2+) ([Ca(2+)](i)), myosin light chain kinase activity and tension (T), but also can inhibit myosin light chain phosphatase activity by activation of rhoA kinase (ROCK), resulting in Ca(2+) sensitization (increased T/[Ca(2+)](i) ratio). Precisely how KCl causes ROCK-dependent Ca(2+) sensitization remains to be determined. Using Fura-2-loaded isometric rings of rabbit artery, we found that the Ca(2+)-independent phospholipase A(2) (iPLA(2)) inhibitor, bromoenol lactone (BEL), reduced the KCl-induced tonic but not early phasic phase of T and potentiated [Ca(2+)](i), reducing Ca(2+) sensitization. The PKC inhibitor, GF-109203X (> or =3 microM) and the pseudo-substrate inhibitor of PKCzeta produced a response similar to BEL. BEL reduced basal and KCl-stimulated myosin phosphatase phosphorylation. Whereas BEL and H-1152 produced strong inhibition of KCl-induced tonic T (approximately 50%), H-1152 did not induce additional inhibition of tissues already inhibited by BEL, suggesting that iPLA(2) links KCl stimulation with ROCK activation. The cPLA(2) inhibitor, pyrrolidine-1, inhibited KCl-induced tonic increases in [Ca(2+)](i) but not T, whereas the inhibitor of 20-HETE production, HET0016, acted like the ROCK inhibitor H-1152 by causing Ca(2+) desensitization. These data support a model in which iPLA(2) activity regulates Ca(2+) sensitivity. PMID:19487023

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

2009-07-01

72

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

73

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

74

Structure of halophilic malate dehydrogenase in multimolar KCl solutions from neutron scattering and ultracentrifugation.  

PubMed

The structure and solvent interactions of malate dehydrogenase from Halobacterium marismortui in multimolar KCl solvents are found to be similar to those in multimolar NACl solvents reported previously (G. Zaccai, E. Wachtel and H. Eisenberg, J. Mol. Biol. 190 (1986) 97). KCl rather than NaCl is predominant in physiological medium. At salt concentrations up to about 3.0 M, the protein (a dimer of M 87000 g/mol) can be considered to occupy an invariant volume in which it is associated with about 4100 molecules of water and about 520 molecules of salt. At very low resolution, the enzyme particle appears to have a compact protein core and protruding protein parts in interaction with the water and salt components, structural features that are not observed in non-halophilic mitochondrial malate dehydrogenase. The above conclusions were drawn from the analysis of neutron scattering and ultracentrifugation data, and the complementarity of these approaches is discussed extensively. PMID:17010283

Calmettes, P; Eisenberg, H; Zaccai, G

1987-05-01

75

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

PubMed

The nonlinear optical single crystals of doped sulphamic acid (SA) were grown from aqueous solution by doping with NaCl and KCl using slow evaporation method. Powder X-ray diffraction studies confirm that the grown crystals belong to orthorhombic system. The density and melting point measurements of the grown crystals were determined by floatation technique and capillary tube method, respectively. The range of optical transmittance was ascertained by recording the UV-Vis-NIR spectrum. Atomic absorption study reveals the presence of dopants in the doped crystals. The thermal analyses indicated that the doped SA crystals are more stable than pure crystals. The Vicker's microhardness studies revealed that the dopants increased the hardness of the crystals. SHG efficiency studies of the crystals are found to be increased in the presence of NaCl and KCl dopants. PMID:21855404

Thaila, T; Kumararaman, S

2011-11-01

76

Thermoluminescence properties of KCl(1-X)KBrX:Pb2+ mixed crystals.  

PubMed

A study is presented of the thermoluminescence (TL) of phosphors based on potassium halides doped with divalent lead, such as KCl:Pb2+, KBr:Pb2+ and the crystalline series KCl(1-X)Br(X):Pb2+. The defects in the crystals generated by irradiation have been investigated as well as the trapping and room temperature recombination mechanisms. The samples were gamma irradiated to a dose of 10 kGy. The TL spectral response during the recombination stage was obtained through simultaneous measurements of temperature, emitted light intensity and emission wavelength by using an automated thermoluminescence system with optical fibre couplings and a diode array as a detection device. The TL emission is a broad band in the 350-600 nm range with a maximum strongly dependent upon the mixed composition. PMID:12382920

Cruz-Zaragoza, E; Meléndrez, R; Chernov, V; Barboza-Flores, M; Piters, T M; Hernández, J A; Murrieta, H S

2002-01-01

77

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

78

Electrodeposition of magnesium from the eutectic LiCl–KCl melt  

Microsoft Academic Search

Electrodeposition of magnesium in the eutectic LiCl--KCl mixture (58--42 mol%) containing different MgCl2 concentrations was studied using tungsten as cathode material. The temperature was varied above and below the melting point of magnesium (983 K). Electrochemical techniques such as cyclic voltammetry, chronopotentiometry and chronoamperometry were employed in order to characterise the system and study nucleation and growth of the magnesium

A. M. Martínez; B. Børresen; G. M. Haarberg; Y. Castrillejo; R. Tunold

2004-01-01

79

Viscosity and structure correlations in NaCl and KCl melts at high pressures  

NASA Astrophysics Data System (ADS)

Knowledge of the structure and physical property change of melts and fluids at high pressures is important for understanding the nature of the Earth's interior. Recently, we have developed synchrotron techniques that are capable of conducting structure measurement of liquid at high-pressure and high-temperature conditions in a Paris-Edinburgh cell by using multi-angle energy-dispersive x-ray diffraction at the 16-BM-B, HPCAT at the Advanced Photon Source (APS), in collaboration with GSECARS. In addition to the structure measurement, we newly developed falling sphere viscosity measurement using x-ray radiography with high-speed camera (> 1000 frame/second), which enables us to investigate viscosity of not only high viscos melts such as silicate or oxide melts but also low viscos liquids and fluids such as H2O and CO2 (around 1 mPa s or less at ambient pressure). Here we report a study of viscosity and structure change in NaCl and KCl melts at high pressures to 7.3 GPa. Viscosity of the NaCl melt continuously increased with increasing pressure to 7.3 GPa. In contrast, viscosity of the KCl melt first increased up to 2.2 GPa, and then remained at a certain level at higher pressures in 2.2-5.9 GPa. Structure measurement of NaCl and KCl melts revealed that the nearest (r1) and the second nearest (r2) neighbor distance gradually shortened with increasing pressure, while the ratio (r2/r1) changes as a function of pressure resembled the behavior of viscosity of both melts. These observations suggest that viscosities of NaCl and KCl melts at high pressures strongly correlate with the changes of the r2/r1 ratio rather than the distance variation only.

Kono, Y.; Kenney-Benson, C.; Park, C.; Shen, G.; Wang, Y.

2012-12-01

80

Investigation of the evaporation of rare earth chlorides in a LiCl–KCl molten salt  

Microsoft Academic Search

Uranium dendrites which were deposited at a solid cathode of an electrorefiner contained a certain amount of salts. These\\u000a salts should be removed for the recovery of pure metal using a cathode processor. In the uranium deposits from the electrorefining\\u000a process, there are actinide chlorides and rare earth chlorides in addition to uranium chloride in the LiCl–KCl eutectic salt.\\u000a The

Sung Bin Park; Dong Wook Cho; Moon Sik Woo; Sung Chan Hwang; Young Ho Kang; Jeong Guk Kim; Hansoo Lee

2011-01-01

81

Mg2+\\/KCL-ATPase of Plant Plasma Membranes is an Electrogenic Pump  

Microsoft Academic Search

The function of the Mg2+-requiring KCl-stimulated ATPase (ATP phosphohydrolase, EC 3.6.1.3) of higher plants in active ion transport was investigated by using a purified microsomal fraction containing sealed plasma membrane vesicles. (Sze, H. (1980) Proc. Natl. Acad. Sci. USA 77, 5904-5908). A transmembrane electrical potential (+30 to +44 mV), monitored by uptake of a permeant anion (35SCN-), was generated specifically

Heven Sze; Kathleen A. Churchill

1981-01-01

82

Third-Order Elastic Constants of NaCl and KCl Single Crystals  

Microsoft Academic Search

Measurements have been made to determine the third-order elastic constants of NaCl and KCl single crystals. The relations between the velocities of ultrasonic waves propagating along the [11¯0] and [1¯1¯2] directions under a uniaxial compression applied in the [111] direction and the elastic constants were derived. Six velocities of these ultrasonic waves were then measured at room temperatures as functions

Zung-Ping Chang

1965-01-01

83

Effect of high KCl concentrations on membrane-localized metastable proton buffering domains in thylakoids  

Microsoft Academic Search

Recent work showed that chloroplast thylakoid membranes stored in 100 mM KCl-containing media have delocalized energy coupling consistent with a rapid equilibration of the proton gradient between the proton-producing redox steps and the lumen bulk phase (Beard and Dilley 1986). Thylakoids stored in low salt media showed localized energy coupling. A related thylakoid membrane property is the occurrence of sequestered,

F. C. Thomas Allnutt; Richard A. Dilley; Tanya Kelly

1989-01-01

84

Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium  

Microsoft Academic Search

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

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

2010-01-01

85

Electrode reaction of plutonium at liquid cadmium in LiCl–KCl eutectic melts  

Microsoft Academic Search

The electrode reaction of the Pu3+\\/Pu couple at the surface of a liquid Cd electrode was investigated by cyclic voltammetry at 723, 773 and 823 K in LiCl?KCl eutectic melt. It was found that the diffusion of Pu3+ in the salt phase was a rate-determining step in the cathodic reaction, but the dissolution of Pu from the liquid Cd phase

O. Shirai; M. Iizuka; T. Iwai; Y. Suzuki; Y. Arai

2000-01-01

86

Electrochemistry of lithium\\/metal sulfide and calcium\\/metal sulfide cells using molten salt electrolytes. [Li\\/LiCl--KCl\\/sulfide and Ca\\/LiCl--KCl--CaClâ\\/sulfide, 700 K  

Microsoft Academic Search

The electrochemical properties of lithium\\/LiCl--KCl\\/metal sulfide and calcium\\/LiCl--KCl--CaClâ\\/metal sulfide cells are described. These cells, which operate at about 700 K, employ intermetallic compounds (rather than elemental lithium or calcium) as their negative electrodes; the positive electrodes are usually iron sulfides, but a variety of other transition metal sulfides have also been tested in lithium cells. The cells with the highest

R. K. Steunenberg; M. F. Roche

1977-01-01

87

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

88

Temperature dependence of the photostimulated luminescence in KCl:Eu2+  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

89

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

90

Electrochemical Removal of AlCl3 from LiCl-KCl Melts  

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

91

Release of mercury halides from KCl denuders in the presence of ozone  

NASA Astrophysics Data System (ADS)

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl2 and HgBr2 lost 29-55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6-100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3-37% of oxidized mercury lost). In addition, collection efficiency decreased by 12-30% for denuders exposed to 50 ppb ozone during collection of HgCl2. While data presented were obtained from laboratory tests and as such do not exactly simulate field sampling conditions, these results indicate that the KCl denuder oxidized mercury collection method may not be as robust as previously thought. This work highlights needs for further testing of this method, clear identification of gaseous oxidized mercury compounds in the atmosphere, and development of field calibration methods for these compounds.

Lyman, S. N.; Jaffe, D. A.; Gustin, M. S.

2010-09-01

92

Release of mercury halides from KCl denuders in the presence of ozone  

NASA Astrophysics Data System (ADS)

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl2 and HgBr2 lost 29-55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6-100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3-37% of oxidized mercury lost). In addition, collection efficiency decreased by 12-30% for denuders exposed to 50 ppb ozone during collection of HgCl2. While data presented were obtained from laboratory tests and as such do not exactly simulate field sampling conditions, these results indicate that the KCl denuder GOM collection method may not be as robust as previously thought. This work highlights needs for further testing of this method, clear identification of gaseous oxidized mercury compounds in the atmosphere, and development of field calibration methods for these compounds.

Lyman, S. N.; Jaffe, D. A.; Gustin, M. S.

2010-05-01

93

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

94

Diffusion coefficients of cerium and gadolinium in molten LiCl-KCl  

SciTech Connect

The most important step in the pyrometallurgical reprocessing is the electrorefining in molten chlorides. In this step, spent metal fuel is anodically dissolved into LiCl-KCl eutectic melt, and the actinides are selectively recovered at the cathodes due to the differences among the redox potentials of the elements, while fission products remain in the anode and in the electrolyte salt. The diffusion coefficients of Ce(III) and Gd(III) in LiCl-KCl eutectic melt were determined in the temperature range between 673 and 823 K by chronopotentiometry. A new method was devised to minimize the error in defining the surface area of the working electrode. The immersed depth of the working electrode was changed by stages, and the relation between the change in the square root of the transition time and that in the surface area of the working electrode was substituted into the Sand equation instead of their absolute values. The activation energies for diffusion and the diffusion coefficients of lanthanide ions in LiCl-KCl are discussed in connection with their ionic radii and the stability of their complex ions.

Iizuka, Masatoshi [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

1998-01-01

95

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

Microsoft Academic Search

Using a numerical Gibbs free-energy minimization technique, the activity coefficients of actinide and rare-earth chlorides in molten LiCl\\/KCl eutectic at 450 C have been calculated. Laboratory tests of an electrochemical process for separating actinide metals from rare-earth metals in LiCl\\/KCl solvent at 450 C provided experimental concentration and cathode potential data. The generalized expansion by Wohl was used to express

Tom B. Bechtel; Truman S. Storvick

1999-01-01

96

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

97

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

98

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

99

Charged pion production in C+C and Ar+KCl collisions measured with HADES  

E-print Network

Results of a study of charged pion production in 12C+12C collisions at incident beam energies of 1A GeV and 2A GeV, and 40Ar+natKCl at 1.76AGeV, using the spectrometer HADES at GSI, are presented. We have performed a measurement of the transverse momentum distributions of pi+- mesons covering a fairly large rapidity interval, in case of the C+C collision system for the first time. The yields, transverse mass and angular distributions are compared with a transport model as well as with existing data from other experiments.

The HADES Collaboration; P. Tlusty; G. Agakishiev; A. Balanda; G. Bellia; D. Belver; A. Belyaev; A. Blanco; M. Boehmer; J. L. Boyard; P. Braun-Munzinger; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Diaz; F. Dohrmann; A. Dybczak; L. Fabbietti; O. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Froehlich; T. Galatyuk; J. A. Garzon; R. Gernhaeuser; A. Gil; C. Gilardi; M. Golubeva; D. Gonzalez-Diaz; E. Grosse; F. Guber; M. Heilmann; T. Hennino; R. Holzmann; A. Ierusalimov; I. Iori; A. Ivashkin; M. Jurkovic; B. Kaempfer; K. Kanaki; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; A. Kozuch; A. Krasa; F. Krizek; R. Kruecken; W. Kuehn; A. Kugler; A. Kurepin; J. Lamas-Valverde; S. Lang; J. S. Lange; K. Lapidus; T. Liu; L. Lopes; M. Lorenz; L. Maier; A. Mangiarotti; J. Marin; J. Markert; V. Metag; B. Michalska; J. Michel; D. Mishra; E. Moriniere; J. Mousa; C. Muentz; L. Naumann; R. Novotny; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; T. Perez Cavalcanti; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; A. Rustamov; A. Sadovsky; P. Salabura; A. Schmah; R. Simon; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Stroebele; J. Stroth; C. Sturm; M. Sudol; A. Tarantola; K. Teilab; M. Traxler; R. Trebacz; H. Tsertos; I. Veretenkin; V. Wagner; M. Weber; M. Wisniowski; J. Wuestenfeld; S. Yurevich; Y. Zanevsky; P. Zhou; P. Zumbruch

2009-06-12

100

A light induced configurational change of FA centres in Li doped KCl-KBr crystals  

NASA Astrophysics Data System (ADS)

Spectroscopic properties of FA centres in Li doped KCl-KBr mixed crystals were studied. At low temperature light induced spectral shifts, for the FA1 hand towards lower energy and for the FA2 band towards higher energy, were observed. The shifts are proposed to be due to a configurational change where the electron occupied vacancy finds a new location in relation to the neighbouring chlorine and bromine ions. The recovery to the original configuration, obtained in the F ? FA conversion, is a temperature activated process.

Ketolainen, P.; Silfsten, P.

1995-12-01

101

Growth of K(Cl, Br) crystals from aqueous solutions in an X-ray field  

SciTech Connect

The influence of X-rays of different wavelength on the degree of structural quality of K(Cl, Br) crystals of mixed composition grown from aqueous solutions is considered. It is found by the methods of chemical etching, X-ray analysis, pycnometric density, and atomic-force microscopy that X-ray irradiation leads to the formation of crystals with a more perfect substructure and surface morphology and a decrease of the dislocation density and concentration of pores and cavities containing the mother liquor. It is shown that X-ray irradiation can promote preferential incorporation of less electronegative components into the crystal lattice of a solid solution.

Anishchik, V. M., E-mail: Anishchik@bsu.by [Belarussian State University (Belarus); Val'ko, N. G., E-mail: N.Valko@grsu.by; Voina, V. V.; Vorontsov, A. S. [Grodno State University (Belarus)

2008-07-15

102

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

NASA Astrophysics Data System (ADS)

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

Lee, Sungman; Lee, Kitae; Cha, Hyungki

2014-04-01

103

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

104

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

105

Phase relations in the system NaCl-KCl-H sub 2 O: IV. Differential thermal analysis of the sylvite liquidus in the KCl-H sub 2 O binary, the liquidus in the NaCl-KCl-H sub 2 O 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  

SciTech Connect

The sylvite liquidus in the binary system KCl-H{sub 2}O and the liquidus in the ternary system NaCl-KCl-H{sub 2}O 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-H{sub 2}O 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 ({plus minus}0.2) = 12.19 + 0.1557T {minus} 5.4071 {times} 10{sup {minus}5}T{sup 2}, where 400 {le} T {le} 770C. 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 5 of this series). However, all experimental liquidus, solidus, and solvus data used in this analysis are summarized in this report (Part 4) and they are compared with the calculated values based on the analysis.

Iming Chou (Geological Survey, Reston, VA (United States)); Sterner, S.M.; Pitzer, K.S. (Univ. of California, Berkeley, CA (United States))

1992-06-01

106

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

107

Mutations in the K+/Cl- cotransporter gene kazachoc (kcc) increase seizure susceptibility in Drosophila.  

PubMed

During a critical period in the developing mammalian brain, there is a major switch in the nature of GABAergic transmission from depolarizing and excitatory, the pattern of the neonatal brain, to hyperpolarizing and inhibitory, the pattern of the mature brain. This switch is believed to play a major role in determining neuronal connectivity via activity-dependent mechanisms. The GABAergic developmental switch may also be particularly vulnerable to dysfunction leading to seizure disorders. The developmental GABA switch is mediated primarily by KCC2, a neuronal K+/Cl- cotransporter that determines the intracellular concentration of Cl- and, hence, the reversal potential for GABA. Here, we report that kazachoc (kcc) mutations that reduce the level of the sole K+/Cl- cotransporter in the fruitfly Drosophila melanogaster render flies susceptible to epileptic-like seizures. Drosophila kcc protein is widely expressed in brain neuropil, and its level rises with developmental age. Young kcc mutant flies with low kcc levels display behavioral seizures and demonstrate a reduced threshold for seizures induced by electroconvulsive shock. The kcc mutation enhances a series of other Drosophila epilepsy mutations indicating functional interactions leading to seizure disorder. Both genetic and pharmacological experiments suggest that the increased seizure susceptibility of kcc flies occurs via excitatory GABAergic signaling. The kcc mutants provide an excellent model system in which to investigate how modulation of GABAergic signaling influences neuronal excitability and epileptogenesis. PMID:16943550

Hekmat-Scafe, Daria S; Lundy, Miriam Y; Ranga, Rakhee; Tanouye, Mark A

2006-08-30

108

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

NASA Astrophysics Data System (ADS)

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

Chakraborty, Brahmananda; Wang, Jin; Eapen, Jacob

2013-05-01

109

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

110

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

PubMed

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

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

2003-02-14

111

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

USGS Publications Warehouse

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

Chou, I. -M.

1982-01-01

112

Effect of NaCl and its partial or complete replacement with KCl on some functional properties of defatted Colocynthis citrullus L. seed flour  

Microsoft Academic Search

Effect of NaCl on some hydration and hydration related properties of Colocynthis citrullus L. were investigated together with the possibility of replacing such salt with KCl in food formulation. This study showed that protein solubility increased with increase in salt concentration. Partial replacement of NaCl with KCl did not make any significant difference to protein solubility. Water absorption capacity decreased

L. A. Arogundade; M. O. Akinfenwa; A. A. Salawu

2004-01-01

113

Hyperon production in Ar+KCl collisions at 1.76A GeV  

E-print Network

We present transverse momentum spectra, rapidity distribution and multiplicity of Lambda-hyperons measured with the HADES spectrometer in the reaction Ar(1.76A GeV)+KCl. The yield of Xi- is calculated from our previously reported Xi-/(Lambda+Sigma0) ratio and compared to other strange particle multiplicities. Employing a strangeness balance equation the multiplicities of the yet unmeasured charged Sigma hyperons can be estimated. Finally a statistical hadronization model is used to fit the yields of pi-, K+, K0s, K-, phi, Lambda and Xi-. The resulting chemical freeze-out temperature of T=(76+-2) MeV is compared to the measured slope parameters obtained from fits to the transverse mass distributions of the particles.

G. Agakishiev; A. Balanda; B. Bannier; R. Bassini; D. Belver; A. Belyaev; A. Blanco; M. Böhmer; J. L. Boyard; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Diaz; F. Dohrmann; A. Dybczak; T. Eberl; E. Epple; L. Fabbietti; O. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Froehlich; T. Galatyuk; J. A. Garzon; R. Gernhaeuser; A. Gil; C. Gilardi; M. Golubeva; D. Gonzalez-Diaz; F. Guber; M. Gumberidze; M. Heilmann; T. Heinz; T. Hennino; R. Holzmann; P. Huck; I. Iori; A. Ivashkin; M. Jurkovic; B. Kaempfer; K. Kanaki; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; F. Krizek; R. Kruecken; W. Kuehn; 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. Moriniere; J. Mousa; C. Muentz; L. Naumann; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; T. Perez-Cavalcanti; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; M. Roy-Stephan; A. Rustamov; A. Sadovsky; B. Sailer; P. Salabura; A. Schmah; E. Schwab; J. Siebenson; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Stroebele; J. Stroth; C. Sturm; A. Tarantola; K. Teilab; P. Tlusty; M. Traxler; R. Trebacz; H. Tsertos; V. Wagner; M. Weber; C. Wendisch; M. Wisniowski; T. Wojcik; J. Wuestenfeld; S. Yurevich; Y. Zanevsky; P. Zhou; P. Zumbruch; HADES Collaboration

2010-10-08

114

Dielectron production in Ar+KCl collisions at 1.76A GeV  

E-print Network

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

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

2011-03-04

115

KA2 and KA1 bands in FA(II) KCl:Li crystals  

NASA Astrophysics Data System (ADS)

The strong dichroism photoinduced in an FA(II) KCl:Li crystal by radiation belonging only to the K band shows the writing anisotropy of this band. We suggest that the K band of FA centers is formed of two bands, KA1 and KA2, which characterize the transitions parallel to the axis of the center and the transitions polarized in a plane perpendicular, respectively. By numerically deconvolving the measured spectra of dichroism and assuming a Gaussian law for the dispersion of the absorption cross sections, we obtain the parameters of these two bands and demonstrate that their half-maximum widths vary as those of the FA1 and FA2 bands versus temperature.

May, Marie; Debrus, Solange; Quernet, Bruno

1991-02-01

116

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

PubMed

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

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

2013-12-01

117

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

SciTech Connect

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

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

2009-01-15

118

Inclusive Dielectron Production in Ar+KCl Collisions at 1.76 AGeV studied with HADES  

E-print Network

Results of the HADES measurement of inclusive dielectron production in Ar+KCl collisions at a kinetic beam energy of 1.76 AGeV are presented. For the first time, high mass resolution spectroscopy was performed. The invariant mass spectrum of dielectrons is compared with predictions of UrQMD and HSD transport codes.

The HADES Collaboration; F. Krizek; G. Agakishiev; A. Balanda; G. Bellia; D. Belver; A. Belyaev; A. Blanco; M. Boehmer; J. L. Boyard; P. Braun-Munzinger; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Diaz; F. Dohrmann; A. Dybczak; L. Fabbietti; O. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Froehlich; T. Galatyuk; J. A. Garzon; R. Gernhaeuser; A. Gil; C. Gilardi; M. Golubeva; D. Gonzalez-Diaz; E. Grosse; F. Guber; M. Heilmann; T. Hennino; R. Holzmann; A. Ierusalimov; I. Iori; A. Ivashkin; M. Jurkovic; B. Kaempfer; K. Kanaki; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; A. Kozuch; A. Krasa; R. Kruecken; W. Kuehn; A. Kugler; A. Kurepin; J. Lamas-Valverde; S. Lang; J. S. Lange; K. Lapidus; T. Liu; L. Lopes; M. Lorenz; L. Maier; A. Mangiarotti; J. Marin; J. Markert; V. Metag; B. Michalska; J. Michel; D. Mishra; E. Moriniere; J. Mousa; C. Muentz; L. Naumann; R. Novotny; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; T. Perez Cavalcanti; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; A. Rustamov; A. Sadovsky; P. Salabura; A. Schmah; R. Simon; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Stroebele; J. Stroth; C. Sturm; M. Sudol; A. Tarantola; K. Teilab; P. Tlusty; M. Traxler; R. Trebacz; H. Tsertos; I. Veretenkin; V. Wagner; M. Weber; M. Wisniowski; J. Wuestenfeld; S. Yurevich; Y. Zanevsky; P. Zhou; P. Zumbruch

2009-07-21

119

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

120

A mathematical analysis of agonist- and KCl-induced Ca(2+) oscillations in mouse airway smooth muscle cells.  

PubMed

Airway hyperresponsiveness is a major characteristic of asthma and is generally ascribed to excessive airway narrowing associated with the contraction of airway smooth muscle cells (ASMCs). ASMC contraction is initiated by a rise in intracellular calcium concentration ([Ca(2+)](i)), observed as oscillatory Ca(2+) waves that can be induced by either agonist or high extracellular K(+) (KCl). In this work, we present a model of oscillatory Ca(2+) waves based on experimental data that incorporate both the inositol trisphosphate receptor and the ryanodine receptor. We then combined this Ca(2+) model and our modified actin-myosin cross-bridge model to investigate the role and contribution of oscillatory Ca(2+) waves to contractile force generation in mouse ASMCs. The model predicts that: 1), the difference in behavior of agonist- and KCl-induced Ca(2+) waves results principally from the fact that the sarcoplasmic reticulum is depleted during agonist-induced oscillations, but is overfilled during KCl-induced oscillations; 2), regardless of the order in which agonist and KCl are added into the cell, the resulting [Ca(2+)](i) oscillations will always be the short-period, agonist-induced-like oscillations; and 3), both the inositol trisphosphate receptor and the ryanodine receptor densities are higher toward one end of the cell. In addition, our results indicate that oscillatory Ca(2+) waves generate less contraction than whole-cell Ca(2+) oscillations induced by the same agonist concentration. This is due to the spatial inhomogeneity of the receptor distributions. PMID:20371316

Wang, Inga Y; Bai, Yan; Sanderson, Michael J; Sneyd, James

2010-04-01

121

Muonium to diamagnetic muon conversion in KCl and NaCl revealed by time-differential muon spin resonance  

Microsoft Academic Search

The conversion of muonium into a diamagnetic muon state in KCl and NaCl was directly observed by detecting a time-delayed appearance of diamagnetic muon states with muon spin resonance. The conversion rate, determined from the time-differential resonance signals, shows a thermal activation characteristic in temperature variation.

Y. Morozumi; K. Nishiyama; K. Nagamine

1986-01-01

122

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

123

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

PubMed Central

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

Delpire, Eric

2013-01-01

124

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

125

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

NASA Astrophysics Data System (ADS)

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

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

2005-03-01

126

Studies on sintering process of synthetic hydroxyapatite.  

PubMed

In this study the effect of sintering process in different temperatures on microstructure and morphological properties of sintered hydroxyapatite (HAp) was investigated. HAp powder was prepared by wet precipitation method from following reagents: Ca(OH)2 + H3PO4 in an alkaline conditions. Thermal analysis (TA), X-Ray diffraction method (XRD), FT-IR spectrometry (FT-IR) and scanning electron microscopy (SEM) were used to elaborate the phase composition and properties of sintered HAp samples and raw HAp powder as well. The total and apparent density and total porosity of sintered compacts, shrinkage and weight loss during the sintering were also measured. The results show that there is a difference in sintering behavior of synthetic hydroxyapatites depending on sintering temperature. The main differences refer to the loss of mass, shrinkage, changes in porosity and density of the investigated materials. PMID:24432345

Malina, Dagmara; Biernat, Kamila; Sobczak-Kupiec, Agnieszka

2013-01-01

127

Measurement of standard potentials of actinides (U,Np,Pu,Am) in LiCl–KCl eutectic salt and separation of actinides from rare earths by electrorefining  

Microsoft Academic Search

Pyrochemical separation of actinides from rare earths in LiCl–KCl eutectic–liquid metal systems has been studied. The electromotive forces of galvanic cells of the form, Ag|Ag(I), LiCl–KCl?actinide(III), LiCl–KCl|actinide, were measured and standard potentials were determined for uranium, neptunium and plutonium to be ?1.283 V, ?1.484 V and ?1.593 V (at 450°C vs. Ag\\/AgCl (1wt%–AgCl)), respectively. A typical cyclic voltammogram of americium

Y. Sakamura; T. Hijikata; K. Kinoshita; T. Inoue; T. S. Storvick; C. L. Krueger; J. J. Roy; D. L. Grimmett; S. P. Fusselman; R. L. Gay

1998-01-01

128

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

Microsoft Academic Search

A comprehensive equation of state has been developed for the system KCl-H[sub 2]O at high temperatures and pressures. The equation is based on a theoretical model developed earlier for the system NaCl-H[sub 2]O. Experimental vapor-liquid equilibrium, solid-liquid equilibrium, and density data have been critically evaluated and used to fit the adjustable parameters of the model. The equation of state reproduces

A. Anderko; K. S. Pitzer

1993-01-01

129

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

SciTech Connect

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

Anderko, A.; Pitzer, K.S. (Lawrence Berkeley Lab., CA (United States))

1993-10-01

130

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

SciTech Connect

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

Miron, C.; Bratescu, M. A.; Takai, O. [Graduate School of Engineering, Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); CREST, JST, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Saito, N. [CREST, JST, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2011-06-15

131

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

132

Optical spectroscopy of Pb2+ in doubly doped KCl:Sr(Pb): Detection of Sr precipitates  

NASA Astrophysics Data System (ADS)

The absorption and luminescence of Pb2+ in the A band region (1A1g--> 3T1u) have been studied in KCl:Sr(Pb) (CSr=800 ppm, CPb=5 ppm) as a function of thermal treatments leading to different aggregation-precipitation stages of strontium impurities. Quenched samples show two well-defined bands peaking at 340 and 413 nm which have been associated with the AT and AX emissions within the framework of the Fukuda model. Dynamical structure on the excitation spectra of these bands has been studied by the second-derivative technique showing that both bands present a temperature-sensitive doublet that responds to a dynamical Jahn-Teller effect as reported for Pb2+ in other alkali halides. On the other hand it has been shown that Pb2+ is a good optical probe to study Sr precipitates, indicating that SrCl2 develops by annealing the samples in the temperature range 100-250deC. Long-time annealing at room temperature and in the range 250-300deC produces other Sr precipitates which can be well characterized optically. By taking advantage of these results the optical spectra of Pb2+ in SrCl2 precipitates formed inside the KC1 matrix have been studied.

Bausá, L. E.; Solé, J. García; Orozco, E.

1987-02-01

133

Spectroscopy of isolated PTCDA molecules on the KCl(100) surface: Vibrational spectra and azimuthal orientation  

NASA Astrophysics Data System (ADS)

Small amounts of the model molecule perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) were vacuum deposited on epitaxial KCl films on Ag(100). The use of a low substrate temperature (20 K) during deposition hampered molecular diffusion resulting in isolated monomers on the surface. Fluorescence and fluorescence excitation spectroscopy performed on these monomers yielded highly resolved spectra with narrow lines corresponding to individual vibronic modes. This high resolution in our spectra is caused by a very small inhomogeneous broadening due to well-defined adsorption sites of the molecule on the substrate. Indeed, by polarization dependent fluorescence spectroscopy we show that the flat-lying molecules exhibit a preferred azimuthal orientation on the surface, the long molecular axis being oriented along the [011] or the equivalent [011] direction of the substrate. Furthermore, the high resolution in the spectra allowed a detailed analysis of the vibronic modes. The vibrational modes of the adsorbed molecule are very similar to those of the free PTCDA molecule, but due to the presence of the substrate additional low energy modes which are relevant for the full understanding of the spectra couple to the transition.

Müller, Mathias; Paulheim, Alexander; Marquardt, Christian; Sokolowski, Moritz

2013-02-01

134

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

SciTech Connect

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

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

1999-04-01

135

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

PubMed

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

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

2014-02-13

136

The KCl cotransporter, KCC2, is highly expressed in the vicinity of excitatory synapses in the rat hippocampus  

Microsoft Academic Search

Immunocytochemical visualization of the neuron-specific K+\\/Cl- cotransporter, KCC2, at the cellular and subcellular level revealed an area- and layer-specific diffuse labelling, and a discrete staining outlining the somata and dendrites of some interneurons in all areas of the rat hippocampus. KCC2 was highly expressed in parvalbumin-containing interneurons, as well as in subsets of calbindin, calretinin and metabotropic glutamate receptor 1a-immunoreactive

A. I. Gulyas; A. Sik; J. A. Payne; K. Kaila; T. F. Freund

2001-01-01

137

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

Microsoft Academic Search

The thermally activated Li(Si)\\/LiCl-KCl\\/FeS2 batteries considered are intended for applications which require high reliability and a shelf life of 25 years. In order to determine the feasibility of achieving these requirements, an accelerated aging study was undertaken. The major objective of this work was to identify deleterious chemical reactions that could affect performance and reliability during the 25 year shelf

J. Q. Searcy; P. A. Neiswander

1981-01-01

138

Molal volumes of sucrose in aqueous solutions of NaCl, KCl, or urea at 25°C  

Microsoft Academic Search

The apparent molal volume pv of sucrose in water has been measured at 25°C in the concentration range 0.04–4.4m from precise density measurements. The same property was also determined for dilute solutions of sucrose in mixed aqueous solvents containing NaCl, KCl, or urea. The limiting values pv° and the slopesSv* were obtained in each case, and their significance has been

James Sangster; Tjoon-Tow Tengfl; Fabio Lenzi

1976-01-01

139

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

NASA Astrophysics Data System (ADS)

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

Santhosh, S.; Prabu, S. Balasivanandha

2012-10-01

140

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

NASA Astrophysics Data System (ADS)

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

Bakker, Ronald J.

2012-05-01

141

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

142

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

143

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

144

Resonant Raman scattering and dynamics of the FA(Li+) modes in KCl  

NASA Astrophysics Data System (ADS)

By means of the behavior-type method, the polarized resonant Raman intensities of the three FA(Li+) modes in KCl are analyzed, taking into account the optically induced reorientation of the defect. The FA( 7Li+) center is known to possess two high-frequency Raman-active vibrations, at 216 and at 266 cm-1, which exhibit a regular Li+ isotope shift and a low-frequency resonance at 47 cm-1, which shows a small and anomalous isotope effect. The investigation of their polarized Raman data necessitated an extension of the behavior-type method to the case of resonant scattering. In spite of reorientation effects the Raman scattering excited at the wavelengths of the FA1 or FA2 band is found to be dominated by the resonant contribution of the defects which can still absorb the incident light. From the analysis of the polarized Raman intensities of the 216-cm-1 mode the defect is shown to have only a mirror-plane symmetry, which independently demonstrates the off-axis position of the Li+ ion in FA(Li+). This deviation from C4v[001] symmetry is not observed in the data for the 47- and the 266-cm-1 modes, but within the C1h symmetry group all the modes belong to the representation A', i.e., they are even under reflection. The polarized Raman study, together with the isotope shifts of the Raman modes and considerations of the normal modes of the defect, permits a more detailed description of the dynamics of the FA(Li+) center: The 266- and the 216-cm-1 vibrations strongly involve the Li+-ion motion within the mirror plane, essentially parallel and perpendicular to the defect axis, respectively. The low-frequency mode at 47 cm-1 is an activated band mode in which the Li+ ion hardly participates, similar to the 43-cm-1 mode of the naked Li+ impurity.

Leblans, M.; Joosen, W.; Goovaerts, E.; Schoemaker, D.

1987-02-01

145

The KCl cotransporter isoform KCC3 can play an important role in cell growth regulation  

PubMed Central

The KCl cotransporter (KCC) plays a significant role in the ionic and osmotic homeostasis of many cell types. Four KCC isoforms have been cloned. KCC1 and KCC4 activity is osmolality-sensitive and involved in volume regulation. KCC2, a neuronal-specific isoform, can lower intracellular Cl? and is critical for inhibitory GABA responses in the mature central nervous system. KCC3, initially cloned from vascular endothelial cells, is widely but not universally distributed and has an unknown physiological significance. Here we show a tight link between the expression and activity of KCC3 and cell growth by a NIH/3T3 fibroblast expression system. KCC3 activity is sensitive to [(dihydroindenyl)oxy] alkanoic acid (DIOA) and N-ethylmaleimide and is regulated by tyrosine phosphorylation. Osmotic swelling does not activate KCC3, and the process of regulatory volume decrease is refractory to DIOA, indicating that KCC3 is not involved in volume regulation. KCC3 expression enhances cell proliferation, and this growth advantage can be abolished by the inhibition of KCC3 by DIOA. Fluorescence-activated cell sorting measurements and Western blot analysis show DIOA caused a significant reduction of the cell fraction in proliferative phase and a change in phosphorylation of retinoblastoma protein (Rb) and cdc2, suggesting that KCC3 activity is important for cell cycle progression. Insulin-like growth factor-1 up-regulates KCC3 expression and stimulates cell growth. Tumor necrotic factor-? down-regulates KCC3 expression and causes growth arrest. These data indicate that KCC3 is an important KCC isoform that may be involved in cell proliferation. PMID:11724933

Shen, Meng-Ru; Chou, Cheng-Yang; Hsu, Keng-Fu; Liu, Hsiao-Sheng; Dunham, Philip B.; Holtzman, Eli J.; Ellory, J. Clive

2001-01-01

146

Current view on the functional regulation of the neuronal K(+)-Cl(-) cotransporter KCC2.  

PubMed

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

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

2014-01-01

147

Clustering of neuronal K+-Cl- cotransporters in lipid rafts by tyrosine phosphorylation.  

PubMed

The neuronal K(+)-Cl(-) cotransporter (KCC2) is a membrane transport protein that extrudes Cl(-) from neurons and helps maintain low intracellular [Cl(-)] and hyperpolarizing GABAergic synaptic potentials. Depolarizing gamma-aminobutyric acid (GABA) responses in neonatal neurons and following various forms of neuronal injury are associated with reduced levels of KCC2 expression. Despite the importance for plasticity of inhibitory transmission, less is known about cellular mechanisms involved in more dynamic changes in KCC2 function. In this study, we investigated the role of tyrosine phosphorylation in KCC2 localization and function in hippocampal neurons and in cultured GT1-7 cells. Mutation to the putative tyrosine phosphorylation site within the long intracellular carboxyl terminus of KCC2(Y1087D) or application of the tyrosine kinase inhibitor genistein shifted the GABA reversal potential (E(GABA)) to more depolarized values, indicating reduced KCC2 function. This was associated with a change in the expression pattern of KCC2 from a punctate distribution to a more uniform distribution, suggesting that functional tyrosine-phosphorylated KCC2 forms clusters in restricted membrane domains. Sodium vanadate, a tyrosine phosphatase inhibitor, increased the proportion of KCC2 associated with lipid rafts membrane domains. Loss of tyrosine phosphorylation also reduced oligomerization of KCC2. A loss of the punctuate distribution and oligomerization of KCC2 and a more depolarized E(GABA) were seen when the 28-amino-acid carboxyl terminus of KCC2 was deleted. These results indicate that direct tyrosine phosphorylation of KCC2 results in membrane clusters and functional transport activity, suggesting a mechanism by which intracellular Cl(-) concentrations and GABA responses can be rapidly modulated. PMID:19679663

Watanabe, Miho; Wake, Hiroaki; Moorhouse, Andrew J; Nabekura, Junichi

2009-10-01

148

Molecular evidence for a role for K+-Cl? cotransporters in the kidney  

PubMed Central

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

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

2013-01-01

149

Role of polyamine structure in inhibition of K+-Cl- cotransport in human red cell ghosts.  

PubMed

1. K+-Cl- cotransport in human red cell ghosts is inhibited by divalent inorganic cations, soluble polycations and amphipathic organic cations. These findings suggest a common mechanism of inhibition, namely, binding of the cations to negative charges at the surface of a hydrophobic structure. 2. We have characterized the inhibitory capacity of a number of polyamines in order to obtain information about the nature of the charges with which they interact. Neomycin inhibited swelling-stimulated cotransport. The diquaternary amines dimethonium and decamethonium were relatively ineffective inhibitors. These compounds are thought to shield negative charges, but not bind to them. 3. Comparison of a homologous series of polyamines indicated that primary amines were better inhibitors than secondary amines, that inhibition increased with the charge of the polyamine, and that inhibition increased as the distance separating the amines increased. 4. The results indicate that the negative charges to which polycations bind are multiple and mobile. Since they must be associated with a hydrophobic environment, it is likely that they are negatively charged phospholipids located in the inner leaflet of the bilayer membrane. 5. Heating red cells or ghosts to 49 C denatures spectrin. Heating markedly increased K+ uptake in swollen ghosts but not in shrunken ghosts. The increase in uptake was reversed when swollen ghosts were shrunk even though denaturation of spectrin was not reversed. Polyamines, which inhibited swelling-activated K+ uptake in control ghosts, similarly inhibited the increased uptake in heated ghosts. 6. We speculate that spectrin, which is closely associated with the inner bilayer leaflet, shields negative charges in a volume-dependent manner and so regulates volume-sensitive K+ transport. PMID:10545139

Sachs, J R; Martin, D W

1999-11-01

150

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

151

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

152

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

E-print Network

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

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

2009-07-21

153

Electroconductivity of molten mixtures of LiCl-KCl eutectics with chlorides of rare-earth elements  

NASA Astrophysics Data System (ADS)

The temperature dependences of the specific and molar electroconductivities of LiCl-KCl-LnCl3 (Ln-La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb) molten mixtures were studied. It was shown that the isotherms (1070 K) of molar electroconductivity (?) for most of the studied saline systems have an S-shaped form. The observed patterns of ? isotherms and their dependence on the ratio of components in the saline mixtures under investigation are explained in the context of complex structure of ionic melts.

Kovalevskii, A. V.; Shishalov, V. I.

2011-01-01

154

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

155

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

156

Crystal growth of iron-based superconductor FeSe0.94 by KCl flux method  

NASA Astrophysics Data System (ADS)

Single crystals of iron-based superconductor FeSe0.94, the 11 phase, have been grown using KCl as flux. The size of as-grown crystals is up to 6 × 3 mm2 or 5 × 5 mm2. The relatively big crystal size is achieved by optimizing the experimental scheme. The main phase of the crystal samples is identified to be tetragonal ?-FeSe by X-ray diffraction analysis. The superconducting transition temperature is determined to be around 10 K by both electron transport and diamagnetism measurements.

Ma, M. W.; Yuan, D. N.; Wu, Y.; Dong, X. L.; Zhou, F.

2014-11-01

157

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

158

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

159

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

160

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

161

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

PubMed

During the summer of 2013, we examined the performance of KCl-coated denuders for measuring gaseous oxidized mercury (GOM) by calibrating with a known source of GOM (i.e., HgBr2) at the North Birmingham SouthEastern Aerosol Research and Characterization (SEARCH) site. We found that KCl-coated denuders have near 95% collection efficiency for HgBr2 in zero air (i.e., air scrubbed of mercury and ozone). However, in ambient air, the efficiency of KCl-coated denuders in capturing HgBr2 dropped to 20-54%. We also found that absolute humidity and ozone each demonstrate a significant inverse correlation with HgBr2 recovery in ambient air. Subsequent laboratory tests with HgBr2 and the KCl-coated denuder show that ozone and absolute humidity cause the release of gaseous elemental Hg from the denuder and thus appear to explain the low recovery in ambient air. Based on these findings, we infer that the KCl denuder method underestimates atmospheric GOM concentrations and a calibration system is needed to accurately measure GOM. The system described in this paper for HgBr2 could be implemented with existing mercury speciation instrumentation and this would improve our knowledge of the response to one potentially important GOM compound. PMID:25192054

McClure, Crystal D; Jaffe, Dan A; Edgerton, Eric S

2014-10-01

162

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

163

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

164

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

PubMed

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

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

2014-05-01

165

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

166

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

PubMed

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

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

2014-01-01

167

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

168

Equilibrium distribution of rare earth elements between molten KCl-LiCl eutectic salt and liquid cadmium  

NASA Astrophysics Data System (ADS)

Distribution experiments for several rare earth elements (La, Ce, Pr, Nd and Y) between molten KCl-LiCl eutectic salt and liquid Cd were carried out at 450, 500 and 600°C. The material balance of rare earth elements after reaching the equilibrium and their distribution and chemical states in a Cd sample frozen after the experiment were examined. The results suggested the formation of solid intermetallic compounds at the lower concentrations of rare earth metals dissolved in liquid Cd than those solubilities measured in the binary alloy system. The distribution coefficients of rare earth elements between two phases (mole fraction in the Cd phase divided by mole fraction in the salt phase) were determined at each temperature. These distribution coefficients were explained satisfactorily by using the activity coefficients of chlorides and metals in salt and Cd. Both the activity coefficients of metal and chloride caused a much smaller distribution coefficient of Y relative to those of other elements.

Sakata, Masahiro; Kurata, Masaki; Hijikata, Takatoshi; Inoue, Tadashi

1991-11-01

169

Gutmann Acceptor Properties of LiCl, NaCl, and KCl Buffered Ambient-Temperature Chloroaluminate Ionic Liquids.  

PubMed

Gutmann acceptor numbers have been determined using (31)P nuclear magnetic resonance (NMR) for AlCl(3)/EMIC melts as well as LiCl, NaCl, and KCl neutral buffered melts. In AlCl(3)/EMIC melts, where EMIC is 1-ethyl-3-methylimidazolium chloride, the change in Gutmann acceptor number as a function of the AlCl(3):EMIC melt ratio is attributed to an equilibrium between a monoadduct of triethylphosphine oxide.AlCl(3) and a diadduct of triethylphosphine oxide.2AlCl(3). Observed acceptor numbers for the neutral buffered melts appear linear with respect to the melt's initial mole ratio of AlCl(3):EMIC prior to buffering. The lithium cation appears to be the most Lewis acidic alkali metal cation followed by the sodium and potassium cations. Possible reasons for the change in acceptor number as a function of changing alkali metal cation concentration are presented. PMID:11669690

Mantz, Robert A.; Trulove, Paul C.; Carlin, Richard T.; Theim, Terry L.; Osteryoung, Robert A.

1997-03-12

170

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

SciTech Connect

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

Matsushita, T.; Nakajima, K.; Suzuki, M.; Kimura, K. [Department of Micro Engineering, Kyoto University, Yoshida-honmachi, Sakyo, Kyoto 606-8501 (Japan)

2007-09-15

171

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

172

Supplemental Tables and Flow Chart of Data analysis Table S1 Contains all raw array data for KCl stress and a complete set of YEPD controls  

E-print Network

41 Supplemental Tables and Flow Chart of Data analysis Table S1 Contains all raw array data for KCl the Matrices 1-3 (pgs 8-10 of the supplement) led to the values and errors of the expression components shown glucose stress experiments. Fitting these data using matrix 1 (pg 8 of the supplement) led

Friedman, Nir

173

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

SciTech Connect

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

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

2010-09-15

174

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

NASA Astrophysics Data System (ADS)

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

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

175

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

176

Quantitative analysis of Eu 2+ and Eu 3+ in LiCl-KCl eutectic melt by spectrophotometry and electrochemistry  

NASA Astrophysics Data System (ADS)

The redox behavior of Eu 2+ and Eu 3+ in the LiCl-KCl eutectic at 773 K was investigated. Since the equilibrium potential of the melt is very close to the redox potential of the Eu 3+|Eu 2+ couple, the Eu 2+ and Eu 3+ species coexist. Quantitative analysis of Eu 2+ and Eu 3+ was performed by spectrophotometry and by potentiometry. Under the coexistence of Eu 2+ and Eu 3+, potentiometric titration of Eu ion using a yttria-stabilized zirconia membrane electrode (YSZME) was performed by changing the concentration of O 2-. The formation of the europium oxychloride, EuOCl, was confirmed by X-ray diffraction analysis, whiles no precipitation of the oxides, EuO and Eu 2O 3, was found. The equivalent point of the EuOCl formation ( x = [O 2-] added/[Eu] total) was shifted to a smaller value from the theoretical value ( x = 1) due to the coexisting Eu 2+. The contribution of the coexisting Eu 2+ to the formation of EuOCl was estimated by using [Eu 2+]/[Eu 3+] as determined by potentiometry and this was subtracted from the titration data. The solubility product of EuOCl was determined to be p ks(EuOCl) = 7.81 ± 0.10.

Kim, Tack-Jin; Uehara, Akihiro; Nagai, Takayuki; Fujii, Toshiyuki; Yamana, Hajimu

2011-02-01

177

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

178

The K-Cl Cotransporter KCC3 as an Independent Prognostic Factor in Human Esophageal Squamous Cell Carcinoma  

PubMed Central

The objectives of the present study were to investigate the role of K–Cl cotransporter 3 (KCC3) in the regulation of cellular invasion and the clinicopathological significance of its expression in esophageal squamous cell carcinoma (ESCC). Immunohistochemical analysis performed on 70 primary tumor samples obtained from ESCC patients showed that KCC3 was primarily found in the cytoplasm of carcinoma cells. Although the expression of KCC3 in the main tumor (MT) was related to several clinicopathological features, such as the pT and pN categories, it had no prognostic impact. KCC3 expression scores were compared between the MT and cancer nest (CN), and the survival rate of patients with a CN > MT score was lower than that of patients with a CN ? MT score. In addition, the survival rate of patients in whom KCC3 was expressed in the invasive front of tumor was lower than that of the patients without it. Furthermore, multivariate analysis demonstrated that the expression of KCC3 in the invasive front was one of the most important independent prognostic factors. The depletion of KCC3 using siRNAs inhibited cell migration and invasion in human ESCC cell lines. These results suggest that the expression of KCC3 in ESCC may affect cellular invasion and be related to a worse prognosis in patients with ESCC. PMID:25110711

Ichikawa, Daisuke; Fujiwara, Hitoshi; Konishi, Hirotaka; Komatsu, Shuhei; Okamoto, Kazuma; Otsuji, Eigo

2014-01-01

179

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

SciTech Connect

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

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

2007-07-01

180

Discharge characteristics of lithium-boron alloy anode in molten salt thermal cells. [LiB\\/LiCl-KCl\\/FeSâ depolarizer\\/Fe  

Microsoft Academic Search

Thermal cells comprised of Li-B anodes, LiCl-KCl eutectic electrolyte, and one of three depolarizers, CaCrOâ, LiâCrOâ, or FeSâ, were investigated. These cells require a separator layer to obviate direct redox reactions between the anode and the cathode. The separator developed for these cells is an electrolyte layer immobilized with MgO. MgO is inert with respect to the anode as well

R. Szwarc; R. D. Walton

1980-01-01

181

Activity coefficients of DL-valine in aqueous solutions of KCl at 25°C. Measurement with ion selective electrodes and modelling  

Microsoft Academic Search

Electrochemical cells with two ion selective electrodes, a cation and an anion ion selective electrode, versus a double junction reference electrode were used to measure the activity coefficients of DL-valine at 298.15 K, up to 0.5 molality, in aqueous solutions of KCl up to 1.0 molality. The results obtained in this work are compared with those reported before for the

Mohammad K. Khoshkbarchi; Juan H. Vera

1996-01-01

182

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

183

A Contradiction between Pulsed and Steady-State Studies in the Recombination Kinetics of Close Frenkel Defects in KBr and KCl Crystals  

Microsoft Academic Search

Theoretical study of the kinetics of the correlated annealing of pairs of close (geminate) F-H centers in KCl and KBr crystals controlled by their diffusion and elastic attraction shows that the multi-step (kink) decay in defect concentrations observed more than once in thermostimulated experiments takes place only for very close F-H center pairs which are no further than fourth nearest

Eugene Kotomin; Anatoli Popov; Masamitsu Hirai

1994-01-01

184

Sensory characterisation and consumer acceptability of small calibre fermented sausages with 50% substitution of NaCl by mixtures of KCl and potassium lactate.  

PubMed

The effect of six mixtures with 50% molar substitution of KCl (0-50%) and potassium lactate (0-50%) as NaCl substitutes in small calibre fermented sausages on some sensory parameters and on the acceptability was studied. Also, the relationship between sensory profile and consumer acceptability using external preference mapping was investigated. The results showed that as the K-lactate substitution increased, pH, sweetness, crumbliness and pastiness also increased, and piquantness, hardness, cohesiveness, ripened flavour, acid taste and saltiness decreased. However, the treatments prepared with a high level of salt substitution by KCl showed scores of sensory attributes similar to those of the control. Consumer segmentation showed differences in acceptability between genders, place of residence, educational level and age group. Consumers rejected fermented sausages with high K-lactate substitution but not those with a high KCl substitution. External preference mapping split consumers up into four clusters with different preference patterns. According to these results and from a sensory point of view, it is possible to achieve a reduction of 50% of NaCl in small calibre fermented sausages and to obtain a product acceptable to most consumers. PMID:22063862

Guàrdia, M D; Guerrero, L; Gelabert, J; Gou, P; Arnau, J

2008-12-01

185

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

186

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

187

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

188

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

189

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

190

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

PubMed

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

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

2014-03-15

191

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

192

Ion-pair Formation and Ion Mobilities in Aqueous NaCl and KCl at High Temperatures from Conductance Data  

NASA Astrophysics Data System (ADS)

The electrical conductivity of aqueous solutions of NaCl have been measured at 651 K and 670 K at 28 MPa for molalities up to 1.0 mol/kg. These conductivities plus the results of Hwang et al.(1970), Ritzert and Franck (1968), and Mangold and Franck (1969) for aqueous KCl have been fit to the conductance equation of Turq, et al. (1995) with a consensus mixing rule and either mean spherical approximation or Debye - Hückel activity coefficients. Except at one state point, where the Coulomb interactions are the strongest ( ? *}= (e2)/(4??0 ? k T a) = 17.8, where ? and a are the dielectric constant of water and the closest distance of ions approach, respectively), the simplest model that fits the experimental results reasonably well (± 2-3 %) at molalities up to 4.5 moles/kg is one with only the limiting equivalent conductance and a pair association constant adjusted. Activity coefficients calculated with either the MSA and ionic diameters or with the Debye - Hückel equation of Oelkers and Helgeson (with no salting out) can be used with similar accuracy. At high concentrations this model predicts strong redisociation of the ion pairs which form at low concentrations. The cluster model of Laria, et al.(1990) for the restricted primitive model is consistent with the qualitative predictions of our preferred model of pair association only. The model of Oelkers and Helgeson (1993) with substantial multi-ion association (triplets and quartets) does not fit the data without the physically unrealistic salting out coefficient so this model is not recommended. For the state point with the highest betastarr (NaCl at 670 K and 28 MPa), more complex models are needed at concentrations above 0.05 mol/kg. Good fits to the data were found for multi-ion association models (5 adjustable parameters) and reasonable fits were found with only pair association and more complex activity models (4 adjustable parameters) so that the models are about equally accurate at equal complexities for this solution.

Balashov, V. N.; Balashov, V. N.; Wood, R. H.; Sharygin, A. V.; Zimmerman, G. H.

2001-12-01

193

The properties of the surface of molten mixtures of the LiCl-KCl eutectic with praseodymium, samarium, erbium, and ytterbium chlorides  

NASA Astrophysics Data System (ADS)

The temperature dependence of surface tension was studied and the excess Gibbs energy of the surface of a sphere with a molar volume of molten quasi-binary mixtures of the LiCl-KCl eutectics with LnCl3 (Ln = Pr, Sm, Er, and Yb) was calculated. The influence of rare-earth and alkali metal cations on the surface properties of the systems studied was considered. Deviations from ideal surface tension isotherms and excess Gibbs energy of the surface of a sphere with a molar volume are explained by the complex structure of melts.

Shishalov, V. I.; Kovalevskii, A. V.

2011-01-01

194

Characteristics of Oxidation Reaction of Rare-earth Chlorides for Precipitation in LiCl-KCl Molten Salt by Oxygen Sparging  

Microsoft Academic Search

The precipitation reaction of some rare earth chlorides (La\\/Ce\\/Nd\\/GdCl3) in a LiCl-KCl molten salt has been carried out by using the oxygen sparging method. In this study, regardless of the oxygen sparging time and the molten salt temperature, oxychlorides (REOCl) for LaCl3, NdCl3 and GdCl3, and an oxide (REO2) for CeCl3 are formed as a precipitate. The conversion of rare-earth

Yong-Jun CHO; Hee-Chul YANG; Hee-Chul EUN; Eung-Ho KIM; In-Tae KIM

2006-01-01

195

Ternary Solution Mutual Diffusion Coefficients and Densities of Aqueous Mixtures of Sucrose with NaCl and Sucrose with KCl at 25°C  

Microsoft Academic Search

Ternary solution isothermal mutual diffusion coefficients (interdiffusion coefficients) have been measured for aqueous mixtures of 0.250 mol-dm-3 sucrose (component 1) with 0.5 and 1.0 mol-dm-3 NaCl or with 0.5 and 1.0 mol-dm-3 KCl (salt = component 2) at 25.00°C using Rayleigh interferometry with computerized data acquisition. Densities were also measured. The volume-fixed diffusion coefficients (Dij)V show the following characteristics. At

Michelle C. Yang; John G. Albright; Joseph A. Rard; Donald G. Miller

1998-01-01

196

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

197

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

NASA Astrophysics Data System (ADS)

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

Ulrich, Thomas; Mavrogenes, John

2008-05-01

198

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

SciTech Connect

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

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

2010-02-15

199

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

PubMed

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

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

2010-01-01

200

(4 mg) was concentrated by vacuum dialysis against 100 mM KCl, 100 mM NaCl, 5 mM potassium phosphate (pH  

E-print Network

and extended to 3.2 Ã?. Data were collected on beamline F-1 at the Cornell High-Energy Synchrotron Source (CHESS(4 mg) was concentrated by vacuum dialysis against 100 mM KCl, 100 mM NaCl, 5 mM potassium

Vale, Ronald D.

201

Gas-solid carbonation of Ca(OH)2 and CaO particles under non-isothermal and isothermal conditions by using a thermogravimetric analyzer  

E-print Network

, dust and aerosols with natural and/or anthropogenic atmospheric gases). In basic or applied research are ubiquitous in many natural and artificial environments (e.g., instantaneous or slow reactions of volcanic ash

Boyer, Edmond

202

Influences of H 2 and O 2 and in situ Ca(OH) 2 absorption on nonthermal plasma decomposition of trichloroethylene in N 2  

Microsoft Academic Search

The decomposition of trichloroethylene (TCE) with a wire-in-tube pulsed corona reactor was experimentally investigated. It was found that the decomposition of TCE was higher in N2 gas, compared to the decomposition in the gas stream containing H2 or O2 gas. The main gaseous products were HCl and Cl2 for TCE decomposition in N2 gas. With the existence of 2% H2

Liwei Huang; Takafumi Fujita; Xuemei Zhang; Hitoki Matsuda

2006-01-01

203

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

PubMed

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

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

2012-09-27

204

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

SciTech Connect

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

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

2011-09-15

205

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

NSDL National Science Digital Library

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

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

2006-10-01

206

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

NASA Astrophysics Data System (ADS)

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

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

2005-04-01

207

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

208

Ovariectomy modulation of morphine analgesia of neuropathic pain is associated with the change of K+-Cl- cotransporter 2 protein level in spinal dorsal horn  

PubMed Central

Sex differences in opioid analgesia have been confirmed both in clinical and experimental studies. Gonadal hormones (estrogens in particular) have a great role in this process. However, the mechanisms that underlie these sex differences are not very clear. In this study, we used K+-Cl- cotransporter 2 (KCC2) as a molecule target to investigate the mechanism underlying the phenomenon. Sprague-Dawley rats were randomly assigned to ovariectomy (OVX)+morphine group, OVX+Saline group, sham surgery (OVX-sham)+morphine group and OVX-sham+saline group. All the rats received SNI surgery three weeks after ovariectomy. We used von Frey values as a sign of neuropathic pain. On PO day 14, 1 ?g morphine or the vehicle saline was administered intrathecally via a PE-10 catheter formerly implanted. Hindpaw withdrawal threshold was determined before and 30, 60, 90, 120, 150, 180 min after drugs injection. The L4-L5 segments of the spinal cord were removed and immunoblotted for KCC2 protein at the time of 2 and 3 h after drugs administration. We find that ovariectomy can regulate the sensitivity to morphine analgesia of neuropathic pain and KCC2 protein level will change in the spinal dorsal horn.

Shen, Weijun; Shen, Liang; Chen, Guoqiang; Wang, Fen; Li, Cheng; Lin, Fuqing; Yang, Xiaohu; Fu, Shukun

2014-01-01

209

Apparent and partial molal volumes in mixed salt solutions. I. The ternary systems LiCl-LiNO3-H2O, NaCl-NaNO3-H2O and KCl-KNO3-H2O  

Microsoft Academic Search

The densities of aqueous mixtures of LiCl-LiNO3, NaCl-NaNO3, and KCl-KNO3 were determined at 25 °C at constant chloride-nitrate molality ratios. The mean apparent molal volumes were calculated and found to obey the limiting law modified by additional terms in ionic strength. The partial molal volumes for the electrolytes in each mixture were calculated and the conditions under which Young and

J. Padova; I. Lewkowicz

1976-01-01

210

Speciation of the Ternary Complexes of Vanadium(III)–Dipicolinic Acid with the Amino Acids Glycine, Proline, ? Alanine and ? Alanine Studied in 3.0 mol?dm ?3 KCl at 25?°C  

Microsoft Academic Search

In this paper we present speciation results for the ternary vanadium(III)–dipicolinic acid (H2dipic) systems with the amino acids glycine (Hgly), proline (Hpro), ?-alanine (H?-ala), and ?-alanine (H?-ala), obtained by means of electromotive forces measurements emf(H) using 3.0 mol?dm?3 KCl as the ionic medium and a temperature of 25?°C. The experimental data were analyzed by means of the computational least-squares\\u000a program LETAGROP,

Carmen Batista; José Daniel Martínez; Mary Lorena Araujo; Felipe Brito; Giuseppe Lubes; Mildred Rodríguez; Vito Lubes

2011-01-01

211

Effects of ionic strength on the regulation of Na/H exchange and K-Cl cotransport in dog red blood cells  

PubMed Central

Dog red cell membranes contain two distinct volume-sensitive transporters: swelling-activated K-Cl cotransport and shrinkage- activated Na/H exchange. Cells were prepared with intracellular salt concentration and weight percentage of cell water (%cw) varied independently by transient permeabilization of the cell membrane to cations. The dependence of transporter-mediated Na and K influxes upon %cw and upon extracellular salt concentration (c(ext)) was measured in cells so prepared. It was found that the critical value of %cw at which transporters are activated, called the set point, is similar for the two transporters, and that the set points for the two transporters decrease similarly with increasing extracellular salt concentration. These findings suggest a common mechanism of regulation of these two transporters. Cellular Na, K, and Cl concentrations were measured as functions of %cw and c(ext). Using these data together with data from the literature for other solute concentrations, empirical expressions were developed to describe the dependence of the intracellular concentrations of all significant small molecule electrolytes, and therefore the intracellular ionic strength, upon %cw and c(ext). A mechanistic model for the dependence of the set point of an individual transporter upon intracellular ionic strength is proposed. According to this model, the set point represents a critical extent of association between the transporter and a postulated soluble regulatory protein, called regulator. Model functions are presented for the calculation of the thermodynamic activity of regulator, and hence extent of regulator- transporter association, as a function of total intracellular protein concentration (or %cw) and ionic strength. The experimentally observed dependence of set point %cw on c(ext) are simulated using these functions and the empirical expressions described above, together with reasonable but not uniquely determined values of model parameters. PMID:7561739

1995-01-01

212

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

213

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

214

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

215

Electrochemical-Impedance-Spectroscopy (EIS) Study of Corrosion of Steels 12CrMoV and SS304 Beneath a Molten ZnCl 2 –KCl Film at 400 °C in Air  

Microsoft Academic Search

The corrosion resistance of 12CrMoV and SS304 steels in contact with a molten mixture of (55–45) mol.% ZnCl2–KCl, similar to that found in waste-incineration plants, has been examined in air at 400 °C by the electrochemical-impedance-spectroscopy\\u000a (EIS) technique. The initial Nyquist plots of 12CrMoV showed a semicircle at high frequency and a line at low frequency indicating\\u000a a diffusion-controlled reaction. At

T. J. Pan; W. M. Lu; Y. J. Ren; W. T. Wu; C. L. Zeng

2009-01-01

216

Speciation of the Ternary Complexes of Vanadium(III)–Dipicolinic Acid and the Amino Acids Cysteine, Histidine, Aspartic and Glutamic Acids in 3.0 mol?dm ?3 KCl at 25?°C  

Microsoft Academic Search

In this work we present results for the speciation of the ternary complexes formed in the aqueous vanadium(III)–dipicolinic\\u000a acid and the amino acids cysteine (H2cys), histidine (Hhis), aspartic acid (H2asp) and glutamic acid (H2glu) systems (25?°C; 3.0 mol?dm?3 KCl as ionic medium), determined by means of potentiometric measurements. The potentiometric data were analyzed with the\\u000a least-squares program LETAGROP, taking into

Isaida Shiozawa; Giuseppe Lubes; Mildred Rodríguez; Vito Lubes

2011-01-01

217

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

218

Nitrogen in aramid-based activated carbon fibers by TPD, XPS and XANES  

E-print Network

(m-phenylene isophthalamide)] by either H3PO4 activation, H3PO4­CO2 activation, or simply CO2 or steam activation that nitrogen atoms are present in the 6-membered rings located at the edges of condensed polyaromatic systems of oxidation of the carbon surface. Assuming that a relative N3 increase is indicative of aromatization

219

The intermolecular structure of phosphoric acid-N,N-dimethylformamide mixtures as studied by computer simulation  

NASA Astrophysics Data System (ADS)

The computer simulation of H3PO4-N,N-dimethylformamide (DMF) mixtures over the whole concentration range using molecular dynamic (MD) methods has been carried out. The preferential orientations of the nearest neighbors of H3PO4 and DMF molecules were obtained using the ranked radial distribution functions technique. On the basis of MD results, the parameters of hydrogen bonds between molecules in mixture were calculated. The changes of the intermolecular structure of mixture as a function of acid composition over the whole concentration range were analyzed and reported. Analysis of O...H distance distributions and angles between O-H (H3PO4) and C=O (DMF) or P=O (H3PO4) vector distributions showed that O(DMF) and O(H3PO4) may each have two hydrogen bonds.

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

2011-05-01

220

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

SciTech Connect

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

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

1999-11-01

221

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

LIDAR nleasurenlents of \\vind turbine wake Ineanderi ng J)l'j',lillllL'nl ul \\kcl1~lI1iW wind turbine [1]. The wake dynamics was resol\\cd using a LIDAR based wind speed scanning system. Recent is locatcd inside a small wind Lmn cOllsi:,ting of 7 x 2 MW wind turbines. The LIDAR will be mounted

222

Characterization of phosphoric acid doped TGS single crystals  

NASA Astrophysics Data System (ADS)

Single crystals of phosphoric acid (H3PO4) doped triglycine sulfate (TGSP) are grown from aqueous solution containing 10-50 mol% of H3PO4. Large sized crystals of dimension (70 mm×40 mm×25 mm) suitable for IR detector applications are obtained with 20 mol% 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 glycinium ions in the doped TGSP crystals, which is due to the low incorporation of H3PO4 into the TGS crystal lattice. The dielectric properties TGSP crystals measured in the temperature range 27-65°C and in frequency range 102-105 Hz show a broad transition, and the peak dielectric constant values are reduced with increasing H3PO4 concentration. Hysteresis loops with high coercive fields are observed up to 20 mol% of H3PO4. At a higher concentration, double loops are observed due to the polarization switching inhibition by H3PO4 molecules. Dopant concentration is found to have a marginal influence on the spontaneous polarization of the TGSP crystals.

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

2004-03-01

223

Surface Activity of n-Alkyltrimethylammonium Bromides in Concentrated Orthophosphoric Acid.  

PubMed

The aggregation and interface behavior of alkyltrimethylammonium bromides (CnH2n+1(CH3)3N+Br-: CnTMA with n = 14, 16, 18) have been investigated in concentrated orthophosphoric acid by means of surface tension measurements. Adsorption of these cationic surfactants at the interface between air and aqueous H3PO4 solutions has been determined at 298 K using the Wilehlmy plate method. Measurements in the most concentrated H3PO4-H2O mixture (95% by weight of acid or 17.5 mol/L) were done at the n-decane/H3PO4 interface using the ring method to avoid any contamination with atmospheric moisture. The critical micelle concentration (CMC), the maximum surface concentration, and surface pressure of C16TMA in water-H3PO4 mixtures and of the homologous series of surfactants, CnTMA, in 95%-H3PO4, were determined at 323 K. Benzene has been used as a test solute for solubilization measurements in 95%-H3PO4 containing C16 TMA micelles. From this experimental work, it can be concluded that micelles are forming even in the most concentrated solutions in acid and that the CMC displays a large depression between 4 and 10 mol/L of H3PO4. The maximum surface concentration increases by steps in the lowest (0 to 1 mol/L) and highest range of concentration (8 to 10 mol/L) in acid. The Klevens equation relating the CMC in relation to the chain length of the surfactants holds in 95%-H3PO4. Values obtained for the parameters of the Klevens equation and for the free energy of micellization in 95%-H3PO4 have been compared to other strongly acidic media like concentrated sulfuric or methanesulfonic acids. Copyright 1998 Academic Press. PMID:9710496

Hafiane; Dhahbi; Chasseray; Lemordant

1998-09-01

224

Decomposition of 4-phenoxyphenol to aromatics over palladium catalyst supported on activated carbon aerogel  

Microsoft Academic Search

Carbon aerogel (CA) was prepared by a sol–gel polymerization of resorcinol and formaldehyde, and a series of activated carbon aerogels (ACA-H3PO4-X, X=0, 0.5, 1.0, 2.0, and 3.0) were prepared by a chemical activation using different amount of phosphoric acid (X represented weight ratio of H3PO4 with respect to CA). Palladium catalysts were then supported on activated carbon aerogels (Pd\\/ACA-H3PO4-X, X=0,

Hai Woong Park; Ung Gi Hong; Yoon Jae Lee; In Kyu Song

225

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

226

Grain sorghum response to banded acid?type fertilizers in iron?deficient soil  

Microsoft Academic Search

Two fluid acid?type fertilizers made by mixing urea with H3PO4 or urea with H3PO4 and H2SO4, an ammonium polyphosphate (APP) fluid, and granular triple superphosphate (TSP) and diammonium phosphate (DAP) were banded alone or with FeSO4 in an Fe?deficient Epping silt loam soil (Ustic Torriorthent) in two greenhouse pot experiments. Grain sorghum (Sorghum bicolor L. Moench) forage yields and Fe

J. J. Mortvedt; J. J. Kelsoe

1988-01-01

227

Study of the oxygen reduction reaction (ORR) at Pt interfaced with phosphoric acid doped polybenzimidazole at elevated temperature and low relative humidity  

Microsoft Academic Search

The oxygen reduction reaction on platinum interfaced with phosphoric acid doped PBI at elevated temperature and low relative humidities has been investigated by using a micro band electrode technique. Both the kinetic and the mass transport parameters in the Pt\\/PBI-H3PO4 system are comparable to those of the Pt\\/H3PO4 system under similar conditions. The study suggests that it is the amorphous

Zhenyu Liu; Jesse S. Wainright; Morton H. Litt; Robert F. Savinell

2006-01-01

228

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

229

Surface Activity of n-Alkyltrimethylammonium Bromides in Concentrated Orthophosphoric Acid  

Microsoft Academic Search

The aggregation and interface behavior of alkyltrimethylammonium bromides (CnH2n+1(CH3)3N+Br?: CnTMA with n = 14, 16, 18) have been investigated in concentrated orthophosphoric acid by means of surface tension measurements. Adsorption of these cationic surfactants at the interface between air and aqueous H3PO4solutions has been determined at 298 K using the Wilehlmy plate method. Measurements in the most concentrated H3PO4-H2O mixture

Amor Hafiane; Mahmoud Dhahbi; Xavier Chasseray; Daniel Lemordant

1998-01-01

230

Carbon13 kinetic isotope effects in the decarbonylation of lactic acid of natural isotopic composition in phosphoric acid medium  

Microsoft Academic Search

The13C kinetic isotope effect fractionation in the decarbonylation of lactic acid (LA) of natural isotopic composition by concentrated phosphpric acids (PA) and by 85% H3PO4 has been studied in the temperature interval of 60–150°C. The values of the13C(1) isotope effects in the decarbonylation of lactic acid in 100% H3PO4, in pyrophosphoric acid and in more concentrated phosphoric acids are intermediate

M. Zieli?ski; G. Czarnota; H. Papiernik-Zieli?ska; G. Kasprzyk; L. Gumó?ka; W. Städter

1993-01-01

231

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

SciTech Connect

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

Seely, D. G. [Department of Physics, Albion College, Albion, MI 49224-1831 (United States); Meyer, F. W.; Zhang, H.; Havener, C. C. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)

2009-03-10

232

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

233

Wet Etching of ?-Ga2O3 Substrates  

NASA Astrophysics Data System (ADS)

Wet etching of (100)-oriented ?-Ga2O3 single crystal substrates was carried out using H3PO4 and H2SO4. The etching reactions followed the Arrhenius equation, but the etching in H2SO4 at a high temperature of 190 °C was disturbed by the formation of sulfates on the surface. Considering the higher etching rate over the temperature range of 100-194 °C, H3PO4 is more preferable as an etchant for ?-Ga2O3. Although the isotropic etching led to side etching, a grid pattern in the order of µm was successfully fabricated. These results indicate that this simple and low-cost wet etching using H3PO4 is suitable for isolating devices or patterning structures on ?-Ga2O3 substrates.

Oshima, Takayoshi; Okuno, Takeya; Arai, Naoki; Kobayashi, Yasushi; Fujita, Shizuo

2009-04-01

234

Physicochemical properties of phosphate ester from palm kernel oil  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

235

Physicochemical properties of phosphate ester from palm kernel oil  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

236

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

PubMed

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

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

2005-09-01

237

Follow us on twitter: @CSI_KCL Visit our website  

E-print Network

and outcomes of palliative care The evidence to date #12;Effects on processes of care Feedback allows more comprehensive identification of symptoms in palliative care populations (moderate evidence) Etkind S, Daveson BA on processes of care Feedback allows more comprehensive identification of symptoms in palliative care

Kühn, Reimer

238

Follow us on twitter: @CSI_KCL Visit our website  

E-print Network

/other specialist palliative care providers � Help the Hospices � The Cicely Saunders Institute and funders � The National Council for Palliative Care � NHSIQ � Public Health England #12;Final thoughts � We need to work

Kühn, Reimer

239

Combinatorial Mathematicians based in Britain. Abdullah, Mohammed KCL  

E-print Network

. Staffordshire Butkovic, Dr. Peter Birmingham Byott, Dr. Nigel P. Exeter C Cameron, Prof. Peter J. QMUL Camina, Prof. Alan R. UEA Campbell, Dr. Colin M. St Andrews Candela Pokorna, Dr. P. Cambridge Cannnings, Prof

Codling, Edward A.

240

Combinatorial Mathematicians based in Britain. Abdullah, Mohammed KCL  

E-print Network

Warwick Adamaszek, Michal Warwick Ahmad, Imtiaz Essex Alexoudas, T. RHUL Ali, A. RHUL Ali, L. RHUL Allen, Dr. Keith J. Dundee Efthymiou, Dr. C Warwick Eleftheriou, Andria Essex Ellis, Dr. David Cambridge. RHUL Garrod, Ben Cambridge #12;Gsieniec, Prof. Leszek Liverpool Gate, James Durham Georgiou, Dr

St Andrews, University of

241

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

E-print Network

Kingdom Tel +44 (0)20 7836 5454 Guy's Campus Self-guided tour #12;`A very warm welcome to King's College around the world whom we view as part of the King's `family'. Indeed, I am particularly proud that King, on the South Bank of the Thames and about 20 minutes walk from Waterloo, is Guy's Campus, adjacent to Guy

Applebaum, David

242

Capacitance and impedance of the Pd/KCl interface  

NASA Astrophysics Data System (ADS)

The capacitance and the electrochemical impedance of the interface between solid polycrystalline palladium and a potassium chloride melt are measured, and nonelectrostatic adsorption of chloride ions in this system is supported. The potential dependence of the capacitance has two minima at low frequencies (from 1 Hz to 10 kHz) and one minimum at high frequencies (30-100 kHz). An increase in the temperature leads to an increase in both the capacitance of the double electrical layer and the adsorption capacitance.

Kirillova, E. V.

2013-08-01

243

EQUILIBRIUM AND KINETICS OF DISPERSE DYE ADSORPTION ON ACTIVATED CARBON PREPARED FROM RATTAN SAWDUST BY CHEMICAL ACTIVATION  

Microsoft Academic Search

The liquid-phase adsorption of C.I. Disperse Orange 30 (DO30) onto activated carbon prepared from rattan sawdust by chemical activation with H3PO4. The rattan sawdust was carbonized at 500oC, 2h and impregnated ratio weight with H3PO4 at 1:4.5. The effects of various parameters such as contact time, initial DO30 concentration and pH were investigated at temperature 30±1oC. Langmuir, Freundlich, Temkin and

A. A. AHMAD; B. H. HAMEED; A. L. AHMAD

2008-01-01

244

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

245

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

246

Preparation of activated carbon from cattail and its application for dyes removal  

Microsoft Academic Search

Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature > activated time > impregnation ratio > impregnation time. The optimum condition was found at an impregnation ratio of 2.5, an impregnation time of 9 hr, an activated temperature of 500°C, and an activated

Qianqian Shi; Jian Zhang; Chenglu Zhang; Cong Li; Bo Zhang; Weiwei Hu; Jingtao Xu; Ran Zhao

2010-01-01

247

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

E-print Network

, washed with distilled water and ethanol, and vacuum-dried at 100°C for 10 h. The powders were annealed was prepared by mixing 9.0 g SnF2 and 12 g H3PO4 followed by dissolution in distilled-deionized water DDW

Cho, Jaephil

248

Determination of picloram in waters by sequential injection chromatography with UV detection  

Microsoft Academic Search

Este trabalho descreve um procedimento de cromatografia por injeção seqüencial para a determinação de picloram em águas explorando a baixa pressão de uma coluna monolítica C 18 de 2,5 cm de comprimento. A separação do analito da matriz foi obtida em menos de 60 s usando como fase móvel uma mistura de acetonitrila e H 3 PO 4 5,0 mmol

Luciana B. O. dos Santos; Carlos M. C. Infante; Jorge C. Masini

2010-01-01

249

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

PubMed

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

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

2013-08-01

250

The Preparation of Some Novel Electrolytes: Synthesis of Partially Fluorinated Alkanesulfonic Acids as Potential Fuel Cell Electrolytes.  

National Technical Information Service (NTIS)

The objective of this research was to prepare some strong acids for evaluation by Fort Belvoir as potential fuel cell electrolytes. The major acid, other than phosphoric, H3PO4, currently under investigation by Fort Belvoir as a fuel cell electrolyte is T...

C. Bunyagidj, H. Pietrowska, M. H. Aldridge

1979-01-01

251

LABORATORY EXPERIMENT 4 Alkalimetric Titration of an Acid Mixture  

E-print Network

LABORATORY EXPERIMENT 4 Alkalimetric Titration of an Acid Mixture In this experiment the quantitative composition of a solution, which is a mixture of a monoprotic strong acid (HCl) and a weaker triprotic acid (H3PO4) will be determined by pH- potentiometric methods. This experiment will introduce you

Nazarenko, Alexander

252

Supporting Information for Liu, Reeves, and Stoltz SI 1 Supporting Information for  

E-print Network

and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology SI 2 Materials and Methods Unless otherwise stated, reactions were performed in flame relative to external H3PO4 ( 0.0 ppm). Data for 1 H NMR are reported as follows: chemical shift ( ppm

Stoltz, Brian M.

253

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.

254

Field assessment of lead immobilization in a contaminated soil after phosphate application.  

PubMed

A pilot-scale field demonstration was conducted at a Pb-contaminated site to assess the effectiveness of Pb immobilization using P amendments. The test site was contaminated by past battery recycling activities, with average soil Pb concentration of 1.16%. Phosphate amendments were applied at a 4.0 molar ratio of P/Pb with three treatments: T1, 100% P from H(3)PO(4); T2, 50% from H(3)PO(4)+50% from Ca(H(2)PO(4))(2); and T3, 50% from H(3)PO(4)+5% phosphate rock. Soil samples were collected and characterized 220 days after P application. Surface soil pH was reduced from 6.45 to 5.05 in T1, to 5.22 in T2, and to 5.71 in T3. Phosphate treatments effectively transformed up to 60% of total soil Pb from the non-residual fraction (sum of water soluble and exchangeable, carbonate, Fe-Mn oxide, and organic fractions) to the residual fraction relative to the control. In addition, P treatments reduced Toxicity Characteristic Leaching Procedure (TCLP) Pb from 82 mg l(-1) to below EPA's regulatory level of 5 mg l(-1) in the surface soil. Scanning electron microscopy-energy dispersive X-ray elemental analysis and X-ray diffraction analysis indicated formation of insoluble chloropyromorphite [Pb(5)(PO(4))(3)Cl] mineral in the P-treated soils. Although H(3)PO(4) is necessary to dissolve meta-stable Pb in soil for further lead immobilization, it should be used with caution due to its potential secondary contamination. A mixture of H(3)PO(4) and Ca(H(2)PO(4))(2) or phosphate rock was effective in immobilizing Pb with minimum adverse impacts associated with pH reduction. PMID:12670762

Melamed, Ricardo; Cao, Xinde; Chen, Ming; Ma, Lena Q

2003-04-15

255

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

256

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

Microsoft Academic Search

A comprehensive equation of state has been developed for the system KC1-H 2 O at high temperatures and pressures. The equation is based on a theoretical model developed earlier for the system NaCl-H 2 O. Experimental vapor-liquid equilibrium, solid-liquid equilibrium, and density data have been critically evaluated and used to fit the adjustable parameters of the model. The equation of

Andrzej Anderko; Kenneth S. Pitzer

1993-01-01

257

Removal of Inorganic Contaminants From Simulated Stormwater by Three Sorbents in Columns Under Intermittent Runoff Condition  

Microsoft Academic Search

Combined removal of inorganic contaminants from a synthetic stormwater was investigated by their sorption on hydrous ferric oxide (HFO) (5%), HFO +Ca(OH)2(6%), and HFO +Ca(OH)2+MnO2 (7%) in columns containing 93-95% anthracite, conducted under seven intermittent runoffs, each of 8 h duration with a 40 h (drying) period between them. At the initial period when Ca(OH)2 produced elevated pHs, the HFO column removed

T. Mohammed; S. Vigneswaran; P. Loganathan; J. Kandasamy; R. Aryal

2012-01-01

258

Retrievabilty of calcium hydroxide intracanal medicament with Chitosan from root canals: An in vitro CBCT volumetric analysis  

PubMed Central

Aim: This study compared the amount of aqueous-based and oil-based calcium hydroxide [Ca(OH)2 ] remaining in the canal, after removal with two different chelators 17% EDTA and 0.2% Chitosan in combination with ultrasonic agitation. Materials and Methods: Cleaning and shaping of root canals of 28 mandibular premolar was done and canals were filled either with Metapex or Ca(OH)2 mixed with distilled water. Volumetric analysis was performed utilizing cone beam-computed tomography (CBCT) after 7 days of incubation. Ca(OH)2 was removed using either 17% EDTA or 0.2% Chitosan in combination with ultrasonic agitation. Volumetric analysis was repeated and percentage difference was calculated and statistically analysed using Kruskal-Wallis and Mann-Whitney U test. Results: Both the chelators failed to remove aqueous-based as well as oil-based Ca(OH)2 completely from the root canal. Aqueous-based Ca(OH)2 was easier to be removed than oil-based Ca(OH)2. 0.2% Chitosan was significantly more effective for removal of oil-based Ca(OH)2 (P < 0.01) while both 17% EDTA and 0.2% Chitosan were equally effective in removing aqueous-based Ca(OH)2 . Conclusion: Combination of 0.2% Chitosan and ultrasonic agitation results in lower amount of Ca(OH)2 remnants than 17% EDTA irrespective of type of vehicle present in the mix. PMID:25298647

Vineeta, Nikhil; Gupta, Sachin; Chandra, Aditi

2014-01-01

259

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

NASA Astrophysics Data System (ADS)

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 located at domain boundaries and inside domains is found to be lower, consistent with excess local negative fixed charges. Curiously, no contrast was seen for the screw dislocations at the centers of growth spirals even after H3PO4 treatment. Thus, either these screw dislocations have no gap states, or if they do have gap states, the positions are higher in energy (closer to conduction band edge) than the gap states of other dislocations.

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

2002-11-01

260

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

261

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

262

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

PubMed

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

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

2011-02-01

263

Investigation of etch characteristics of non-polar GaN by wet chemical etching  

NASA Astrophysics Data System (ADS)

We characterized the surface defects in a-plane GaN, grown onto r-plane sapphire using a defect-selective etching (DSE) method. The surface morphology of etching pits in a-plane GaN was investigated by using different combination ratios of H 3PO 4 and H 2SO 4 etching media. Different local etching rates between smooth and defect-related surfaces caused variation of the etch pits made by a 1:3 ratio of H 3PO 4/H 2SO 4 etching solution. Analysis results of surface morphology and composition after etching by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) demonstrated that wet chemical etching conditions could show the differences in surface morphology and chemical bonding on the a-plane GaN surface. The etch pits density (EPD) was determined as 3.1 × 10 8 cm -2 by atom force microscopy (AFM).

Hsu, Hsiao-Chiu; Su, Yan-Kuin; Cheng, Shin-Hao; Huang, Shyh-Jer; Cao, Jia-Ming; Chen, Kuan-Chun

2010-11-01

264

Partially acidulated reactive phosphate rock (PAPR) fertilizer and its reactions in soil  

Microsoft Academic Search

PAPR was made by partial acidulation of North Carolina phosphate rock with H3PO4. The PAPRs were incubated in bands in columns of two soils of contrasting P retention. The columns were sampled after freezing and sectioning with a cryomicrotome. The movement of P in soil incubated with33P-labelled PAPR was followed by autoradiography of polished epoxy impregnated sections of the freeze-dried

D. C. Golden; R. E. White; R. W. Tillman; R. B. Stewart

1991-01-01

265

Study of the hydrolysis of sugar cane bagasse using phosphoric acid  

Microsoft Academic Search

In the present work, samples of sugar cane bagasse were hydrolysed with phosphoric acid under mild conditions (H3PO4 2–6%, time 0–300min and 122°C) to study the feasibility of using the liquid phase as fermentation media. Solid yield, sugar concentrations and decomposition product concentrations were measured. The composition of hydrolysates, their purity and the ratio sugars\\/inhibitors were analyzed. Kinetic models were

Sara Gámez; Juan Jose González-Cabriales; José Alberto Ramírez; Gil Garrote; Manuel Vázquez

2006-01-01

266

Removal of reactive dye from aqueous solutions by adsorption onto activated carbons prepared from sugarcane bagasse pith  

Microsoft Academic Search

Bagasse pith, which is the main waste from sugarcane industry in Egypt, has been used as a raw material for the preparation of different activated carbons. Activated carbons were prepared from bagasse pith by chemical activation with 28% H3PO4 (AC1), 50% ZnCl2 (AC2) followed by pyrolysis at 600°C and by physical activation at 600°C in absence of air (AC3). Different

Nevine Kamal Amin

2008-01-01

267

Chemical Extraction of Arsenic from Contaminated Soil  

Microsoft Academic Search

A series of batch extraction experiments were conducted using a fortified soil with different extracting solutions such as inorganic acids (hydrochloric acid (HCl), sulfuric acid (H2SO4), phosphoric acid (H3PO4), perchloric acid (HClO4), or nitric acid (HNO3)), organic acids (acetic acid (C2H4O2), citric acid (C6H8O7)) and alkaline agent (NaOH). Various concentrations were used to investigate the removal efficiency and to optimise

M. G. M. ALAM; S. TOKUNAGA

2006-01-01

268

Kinetic catalytic determination of trace levels of iodide based on the oxidation of basic dyes with hydrogen peroxide monitored potentiometrically using simple PVC electrodes  

Microsoft Academic Search

Four sensitive catalytic potentiometric methods have been developed for trace levels determination of iodide based on its catalytic effects on the oxidation of four dyes: viz. variamine blue (VB), rhodamine B (RB), methylene blue (MB) and malachite green (MG), with H2O2 in H3PO4 medium at 25±0.5°C. The catalyzed reaction rates were estimated potentiometrically by monitoring the potential of the corresponding

Elmorsy Khaled; M. A. El-Ries; F. I. Zidane; S. A. Ibrahim; M. S. Abd-Elmonem

2011-01-01

269

In vitro metabolism of a nitroderivative of acetylsalicylic acid (NCX4016) by rat liver: LC and LC–MS studies  

Microsoft Academic Search

The metabolism of a nitroderivative of acetylsalicylic acid, benzoic acid, 2-(acetyloxy)-3-[(nitrooxy)methyl]phenyl ester (NCX4016), the lead compound of a new class of NO-releasing non steroidal-antiinflammatory drugs has been studied in vitro in rat liver subcellular fractions (S 9000×g, microsomes, cytosol). Samples were extracted with CH3CN (2 vol.) containing 1% H3PO4 (2 M), vortexed for 3 min and then centrifuged for 5

Marina Carini; Giancarlo Aldini; Marica Orioli; Roberto Maffei Facino

2002-01-01

270

Chemical oxygen demand determination in environmental waters by mixed-acid digestion and single sweep polarography  

Microsoft Academic Search

A new variant of the method for chemical oxygen demand (COD; 20–1100mg O2l?1) determination in environmental waters is described. The method is based on determination of excess Cr(VI) in a mixed-acid (H3PO4–H2SO4) digestion solution by single sweep polarography instead of titrimetry; COD is measured indirectly. The reflux time is shortened to 15min by mixed-acid digestion. The effects of mixed-acid concentration,

Dezhong Dan; Fulai Dou; Dianjie Xiu; Yuanqing Qin

2000-01-01

271

Electrochemical Behavior of Polyaniline, Poly(o-Anisidine) and Their Copolymer Thin Films in Inorganic and Organic Supporting Electrolytes  

Microsoft Academic Search

The influence of inorganic and organic supporting electrolytes on electrochemical, optical, and conducting properties of polyaniline, poly(o-anisidine), and poly(aniline-co-o-anisidine) thin films were investigated. Homo- and copolymer thin films were synthesized electrochemically, under cyclic voltammetric conditions in aqueous solutions of inorganic acids, viz., H2SO4, HCl, HNO3, H3PO4, and HClO4 and organic acids, viz., benzoic acid, cinnamic acid, oxalic acid, malonic acid,

D. D. Borole; U. R. Kapadi; P. P. Mahulikar; D. G. Hundiwale

2005-01-01

272

Phosphorus catalysis in the pyrolysis behaviour of biomass  

Microsoft Academic Search

Phosphorus is a key plant nutrient and as such, is incorporated into growing biomass in small amounts. This paper examines the influence of phosphorus, present in either acid (H3PO4) or salt ((NH4)3PO4) form, on the pyrolysis behaviour of both Miscanthus×giganteus, and its cell wall components, cellulose, hemicellulose (xylan) and lignin (Organosolv). Pyrolysis–gas chromatography–mass spectrometry (PY–GC–MS) is used to examine the

Daniel J. Nowakowski; Charles R. Woodbridge; Jenny M. Jones

2008-01-01

273

Ris Energy Report 3 Introduction  

E-print Network

%. This chapter outlines the technologies, their status, advantages and areas for improvement, and shows how-conducting polymer H3PO4 K-Li-CO3 Y-Zr2O3 Operating temperature ~80°C ~200°C ~650°C ~600-1000°C Advantages Works is rather low, at around 30%, DMFCs are ideal replace- ments for batteries in portable equipment

274

Surfactant-assisted growth of anodic nanoporous niobium oxide with a grained surface  

Microsoft Academic Search

Nanoporous niobium oxide film with a maximum thickness of 520nm was prepared by anodizing niobium in a mixture of 1wt% HF, 1M H3PO4, and a small amount of Sodium Dodecyl Sulfate (SDS) surfactant. The porosity of the anodic niobium oxide prepared without SDS is irregular with the surface of the oxide suggesting a grained surface pattern rather than an ordered

Jeong Eun Yoo; Jinsub Choi

2010-01-01

275

Preparation and thermal stability analysis of hydroxyapatite derived from the precipitation process and microwave irradiation method  

Microsoft Academic Search

Thermally stable hydroxyapatite (HAP) polycrystals were prepared using H3PO4, glucose and Ca(NO3)2·4H2O, as starting materials with microwave irradiation method and coprecipitation method, respectively. The crystal structure was monitored by XRD. The calcium\\/phosphorous molar ratio of the different as-precipitated hydroxyapatite was determined by ICP. The results show that various parameters such as aging time, microwave irradiation power and time have significant

Zhengwen Yang; Yinshan Jiang; YuJie Wang; LiYan Ma; Fangfei Li

2004-01-01

276

Phosphoric acid as a dentin etchant.  

PubMed

This study determined the effect of phosphoric acid (H3PO4) application to dentin on the shear bond strength (SBS) and microleakage of an experimental bonding system. Thirty human maxillary permanent first and second molars were used for the SBS evaluation. In 15 of the teeth the Dentin Conditioner was applied to dentin for 30 seconds (A), while in the remaining 15 teeth the smear layer was removed by the application of a 37% H3PO4 gel for 20 seconds (B). The Primers 1 and 2 were mixed and applied to the conditioned dentin followed by the application of the Dentin Bonding Resin prior to the placement in three increments of the Bisfil-M composite. The specimens were stored in physiological saline at 37 degrees C for 24 hours prior to applying a shear load at a crosshead speed of 0.5 mm. inch-1 in an Instron machine. Shear bond strengths were expressed in MPa. Circular Class V preparations were made on the roots of 30 maxillary permanent canines, 15 restored using the Dentin Conditioner (C) and 15 by removing the smear layer with the H3PO4 gel (D). Microleakage of the restorations was determined quantitatively by means of a spectrophotometric method. The quantitative microleakage was expressed as microgram dye/restoration. The data were analyzed by the Student t-test. The following results were obtained: A: 14.2 +/- 2.2 MPa; B: 7.2 +/- 4.2 MPa; C: 30.0 +/- 28.6 micrograms dye/restoration; (D) 10.3 +/- 8.2 micrograms dye/restoration. Removing the smear layer with H3PO4 reduced the SBS to dentin but decreased the quantitative microleakage significantly. PMID:1524738

Retief, D H; Mandras, R S; Russell, C M; Denys, F R

1992-02-01

277

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

278

On the corrosion resistance of the Delhi iron pillar  

Microsoft Academic Search

The nature of the protective passive layer on the corrosion resistant Delhi iron pillar (DIP) has been addressed based on a detailed characterization of its rust. Rust characterization clearly established that the major constituents of the scale were crystalline iron hydrogen phosphate hydrate (FePO4·H3PO4·4H2O), ?-, ?-, ?-FeOOH and magnetite. The iron oxide\\/oxyhydroxides were present in the amorphous form. The role

R. Balasubramaniam

2000-01-01

279

Stabilization of lateritic soils with phosphoric acid  

Microsoft Academic Search

This paper describes a laboratory study on the stabilization of lateritic soils with phosphoric acid-H3PO4. This method is most promising for road and airport pavement construction in tropical regions where fine textured lateritic soils (red clays and silts) occur over large areas. The iron and aluminum phosphates formed are hard and insoluble. The main source of iron is free iron

J. Medina; H. N. Guida

1995-01-01

280

LC Determination and Bioequivalence Study of Pantoprazole in Human Plasma  

Microsoft Academic Search

A selective and sensitive liquid chromatography (LC) method with rapid sample processing was developed for determination of\\u000a pantoprazole in human plasma using omeprazole as internal standard (IS). The plasma sample (100 ?L) was deproteined by precipitation\\u000a with methanol. The supernatant was directly determined by LC using a Diamonsil C18 ODS column and solution of 10 mM Na2HPO4 buffer (containing 0.01% H3PO4) and

Honggang Lou; Hong Yuan; Zourong Ruan; Donghang Xu; Quan Zhou

2008-01-01

281

The growth of zinc phosphate coatings on 6061Al alloy  

Microsoft Academic Search

Zinc phosphate coating was formed on 6061-Al alloy through a phosphating bath containing mainly ZnO, H3PO4, NaF. Yttrium oxide (Y2O3) was used as an accelerator of phosphatization to replace nitrite. The morphology, composition and the growth process of the zinc phosphate coating were investigated by SEM, EDX, XRD, FTIR and electrochemical measurements. The phosphate coating formed is composed of hopeite

Sheng-lin Zhang; Hua-hui Chen; Xiao-lin Zhang; Ming-ming Zhang

2008-01-01

282

Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation  

Microsoft Academic Search

Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, XP (gH3PO4\\/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000m2\\/g) and high pore volume (up to 1.19cm3\\/g) can

Sandro Altenor; Betty Carene; Evens Emmanuel; Jacques Lambert; Jean-Jacques Ehrhardt; Sarra Gaspard

2009-01-01

283

REMOVAL OF ALUMINUM FROM PICKLING BATH LIQUIDS BY TERTIARY AND QUATERNARY AMINE EXTRACTANTS  

Microsoft Academic Search

In this work, several extractants and solvents have been investigated for the selective removal of aluminum from a pickling bath, containing HF and H3PO4 as its main active components, each at a concentration of 0.01–0.30 M. The final aim of the research is to increase the lifetime of the pickling bath, resulting in reduced operating costs, in a decreased environmental

Anke M. Berends; Geert-Jan Witkamp

2001-01-01

284

Effect of phosphite fertilization on growth, yield and fruit composition of strawberries  

Microsoft Academic Search

Traditionally, phosphates (Pi, salts of phosphoric acid, H3PO4) have been used for plant fertilization, and phosphites (Phi, salts of phosphorous acid, H3PO3) have been used as fungicides. Nowadays several Phi fertilizers are available in the EU market despite the fact that in research trials Phi has often had a negative influence on plant growth. The objective of this study was

Ulvi Moor; Priit Põldma; Tõnu Tõnutare; Kadri Karp; Marge Starast; Ele Vool

2009-01-01

285

Determination of some antipsychotropic and anticholinergic phenothiazine drugs by vanadium (V) titration  

Microsoft Academic Search

Three simple, rapid and accurate titrimetric procedures using ammonium metavanadate have been developed for the determination of six phenothiazine drags in pure form and in dosage forms. The procedures are based on the oxidation of phenothiazines in acid medium to colourless sulphoxides via orange or purple coloured intermediates. In the first method, phenothiazines are titrated directly in H2SO4-H3PO4 medium to

K. Basavaiah; G. Krishnamurthy

1999-01-01

286

Solvent Extraction and Separation of Tervalent Lanthanides and Yttrium Using Cyanex 923  

Microsoft Academic Search

The paper embodies extraction behavior of some tervalent lanthanides [La, Ce, Nd, Eu, Gd, Ho, Yb] along with Y(III) from HNO3, HCl, H2SO4, and H3PO4 media in a toluene solution of Cyanex 923. The effect of some important variables like equilibration time, nature of diluent and the concentration of acid, extractant and metal ion on the extraction is investigated. Based

Bina Gupta; Poonma Malik; Akash Deep

2003-01-01

287

Development and Validation of a Capillary Zone Electrophoresis Method for the Determination of Ofloxacin in Tablets  

Microsoft Academic Search

A capillary zone electrophoresis (CZE) method has been developed for the determination of the antibiotic ofloxacin in tablets. The CZE separation was performed using 75 µm × 35 cm fused silica capillary under the following conditions: 25°C; applied voltage, 12 kV; 25 mM H3PO4-NaOH running buffer (pH 8.5). The detection wavelength was 254 nm. Flumequine was used as internal standard. The method was suitably validated with respect

Abdalla A. Elbashir; Bahruddin Saad; Abdussalam Salhin Mohamed Ali; Muhd. Idiris Saleh; Hassan Y. Aboul-Enein

2008-01-01

288

Surface texturing of p-GaN layer for efficient GaN LED by maskless selective etching  

Microsoft Academic Search

The maskless selective wet etching of p-GaN layer with KOH in ethylene glycol (KE) and H3PO4\\/H2SO4 (HH) acids was developed for the highly efficient light-emitting diodes (LEDs). The p-GaN surfaces textured by the selective wet etching process without using etch mask showed hexagonal and stripe shapes in the KE and HH solutions, respectively. The current-voltage (I-V) characteristics of the LED

Seok-In Na; Dae-Seob Han; Seok-Soon Kim; Jae-Hong Lim; Ja-Yeon Kim; Seong-Ju Park

2005-01-01

289

Micellization and surface activity of Triton X-100 in water–orthophosphoric medium  

Microsoft Academic Search

The adsorption isotherms of Triton X-100 for air\\/water–orthophosphoric acid interfaces were determined by the stripping method. The surface chemical parameters, ?max, F and ?G°A, and the aggregation ones, CMC and the ?GM, are determined in different H2O\\/H3PO4 mixtures. For concentrations higher than 4M, the values of the CMC, ?GM, ?max and ?G°A increase with increasing acid concentrations due to the

Sonia Ouni; Amor Hafiane; Mahmoud Dhahbi

2000-01-01

290

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

291

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

NASA Astrophysics Data System (ADS)

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

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

2003-07-01

292

Kinetic studies on adsorption of chromium by coconut shell carbons from synthetic effluents  

Microsoft Academic Search

The present work deals with the kinetics of chromium (vi) removal from prepared activated coconut shell carbons. The activated carbons were prepared by physical and chemical activation using H2SO4, H3PO4, ZnCl2 activating agents of different Imprignation Ratio (IR). The effect of adsorption of Cr (vi) on pH, particle size concentration, contact time have been studied. Removal of cromium (vi) attained

Padaki Srinivas Rao; Shashikant R. Mise; G. S. Manjunatha

1992-01-01

293

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

NASA Astrophysics Data System (ADS)

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

Erdogan, Pembe; Yuksel, Behiye; Birol, Yucel

2012-03-01

294

Selective and nonselective wet etching of Zn0.9Mg0.1O/ZnO  

NASA Astrophysics Data System (ADS)

Wet etch rates at 25°C for Zn0.9Mg0.1O grown on sapphire substrates by pulsed laser deposition (PLD) were in the range 300 1100 nm · min-1 with HCl/H2O (5×10-3-2×10-2 M) and 120 300 nm · min-1 with H3PO4/H2O (5×10-3-2×10-2 M). Both of these dilute mixtures exhibited diffusion-limited etching, with thermal activation energies of 2 3 kCal · mol-1. By sharp contrast, the etch rates for ZnO also grown on sapphire by PLD were much slower in similar solutions, with rates of 1.2 50 nm · min-1 in HCl/H2O (0.01 1.2 M) and 12 54 nm · min-1 in H3PO4/H2O (0.02 0.15 M). The etching was reaction limited over the temperature range 25 75°C, with activation energies close to 6 kCal · mol-1. The resulting selectivity of Zn0.9Mg0.1O over ZnO can be a high as ˜400 with HCl and ˜30 with H3PO4.

Chen, Jau-Jiun; Jang, Soohwan; Ren, F.; Li, Yuanjie; Kim, Hyun-Sik; Norton, D. P.; Pearton, S. J.; Osinsky, A.; Chu, S. N. G.; Weaver, J. F.

2006-04-01

295

Low-Temperature Properties of H, V, and F Centers in KCl and KBr  

Microsoft Academic Search

Potassium chloride and potassium bromide crystals were exposed to x rays at 10°K. The optical absorption produced by this irradiation and the changes in optical absorption produced by subsequent annealing at higher temperatures were measured. The temperatures at which changes in optical absorption occurred were correlated with the temperatures at which free electrical charge appeared, and thermoluminescence was observed. The

John Cape; Gilbert Jacobs

1960-01-01

296

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

297

The excretion of NaCl and KCl loads in mosquitoes. 1. Control data.  

PubMed

The handling of Na(+) and K(+) loads was investigated in isolated Malpighian tubules and in whole mosquitoes of Aedes aegypti. Isolated Malpighian tubules bathed in Na(+)-rich Ringer solution secreted Na(+)-rich fluid, and tubules bathed in K(+)-rich Ringer solution secreted K(+)-rich fluid. Upon Na(+) loading the hemolymph, the mosquito removed 77% the injected Na(+) within the next 30 min. The rapid onset and magnitude of this diuresis and the excretion of more Na(+) than can be accounted for by tubular secretion in vitro is consistent with the release of the calcitonin-like diuretic hormone in the mosquito to remove the Na(+) load from the hemolymph. Downstream, K(+) was reabsorbed with water in the hindgut, which concentrated Na(+) in excreted urine hyperosmotic to the hemolymph. Upon K(+) loading the hemolymph, the mosquito took 2 h to remove 100% of the injected K(+) from the hemolymph. The excretion of K(+)-rich isosmotic urine was limited to clearing the injected K(+) from the hemolymph with a minimum of Cl(-) and water. As a result, 43.3% of the injected Cl(-) and 48.1% of the injected water were conserved. The cation retained in the hemolymph with Cl(-) was probably N-methyl-d-glucamine, which replaced Na(+) in the hemolymph injection of the K(+) load. Since the tubular secretion of K(+) accounts for the removal of the K(+) load from the hemolymph, the reabsorption of K(+), Na(+), Cl(-), and water must be inhibited in the hindgut. The agents mediating this inhibition are unknown. PMID:25056103

Hine, Rebecca M; Rouhier, Matthew F; Park, Seokhwan Terry; Qi, Zhijun; Piermarini, Peter M; Beyenbach, Klaus W

2014-10-01

298

Office use only www.kcl.ac.uk/iss/igc September 2010  

E-print Network

for access to CCTV images must include:- a) The date and time the images were recorded b) Information to identify the individual, if necessary c) The location of the CCTV camera d) Proof of Identity Fees

Applebaum, David

299

Rapid procedures for preparing soil and KCL extracts for N analysis  

Microsoft Academic Search

An apparatus for grinding plant and soil samples to <250um for N analysis is described. This inexpensive and easily constructed roller grinder uses bottles for grinding individual samples, thus eliminating the potential for cross contamination. The unit running over?night is capable of grinding 70 samples. In addition a method is described for diffusing NH4 and NO3 onto filter paper for

J. L. Smith; Myung Ho Um

1990-01-01

300

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

301

Behavior of plutonium and americium at liquid cadmium cathode in molten LiCl-KCl electrolyte  

NASA Astrophysics Data System (ADS)

The effects of the electrochemical conditions on the behavior of plutonium and proper conditions for plutonium recovery at the liquid cadmium cathode (LCC) used in the pyrometallurgical reprocessing were studied by the electrotransport experiments with small, not stirred electrodes. Plutonium was successfully collected up to 7.75 wt% without disturbance by solid phase formation at the surface. Plutonium collected beyond saturation formed intermetallic compound PuCd 6 and accumulated at the bottom of the LCC. The cathodic current density adequate for plutonium collection was proportional to the concentration of plutonium in the molten salt. The behavior of americium was reasonably explained by a local equilibrium model between plutonium and americium at the surface of the LCC, although thermodynamic study and quantitative analysis are needed for further understanding. The plutonium collection rate in practical electrorefiner was estimated to be 324 g/h for one LCC by extrapolation of the experimental results.

Iizuka, Masatoshi; Uozumi, Koich; Inoue, Tadashi; Iwai, Takashi; Shirai, Osamu; Arai, Yasuo

2001-10-01

302

Behavior of plutonium and americium at liquid cadmium cathode in molten LiCl–KCl electrolyte  

Microsoft Academic Search

The effects of the electrochemical conditions on the behavior of plutonium and proper conditions for plutonium recovery at the liquid cadmium cathode (LCC) used in the pyrometallurgical reprocessing were studied by the electrotransport experiments with small, not stirred electrodes. Plutonium was successfully collected up to 7.75 wt% without disturbance by solid phase formation at the surface. Plutonium collected beyond saturation

Masatoshi Iizuka; Koich Uozumi; Tadashi Inoue; Takashi Iwai; Osamu Shirai; Yasuo Arai

2001-01-01

303

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

E-print Network

. diameter tube of bakelite which was 16 in. long. The solenoid was sus- pended around the glass envelope by a wooden yoke clamped around the upper end of the solenoid. Initially it was suspended from the underside of the suspension system table.... diameter tube of bakelite which was 16 in. long. The solenoid was sus- pended around the glass envelope by a wooden yoke clamped around the upper end of the solenoid. Initially it was suspended from the underside of the suspension system table...

Miller, James Edward

2012-06-07

304

Regional differences in the expression of K(+)-Cl(-) 2 cotransporter in the developing rat cortex.  

PubMed

The type 2 potassium-chloride cotransporter (KCC2) is the main regulator of intracellular chloride concentration in CNS neurons, and plays a crucial role in spine development that is independent of its ion cotransport function. The expression pattern of KCC2 is upregulated during postnatal development showing area and layer-specific differences in distinct brain areas. We examined the regional and ultrastructural localisation of KCC2 in various areas of developing neocortex and paleocortex during the first two postnatal weeks. Light-microscopy examination revealed diffuse neuropil and discrete funnel-shaped dendritic labelling in the piriform and entorhinal cortices at birth. Subsequently, during the beginning of the first postnatal week, diffuse KCC2 labelling gradually started to appear in the superficial layers of the neocortex while the punctate-like labelling of dendrites in the piriform, entorhinal and perirhinal cortices become more pronounced. By the end of the first postnatal week, discrete dendritic expression of KCC2 was visible in all neocortical and paleocortical areas. The expression level did not change during the second postnatal week suggesting that, in contrast to hippocampus, adult pattern of KCC2 in the cortical cells is already established by the end of the first postnatal week. Quantitative electron microscopy examination revealed that in superficial layers of both neo- and paleocortex, the majority of KCC2 signal was plasma membrane associated but the number of transport vesicle-associated immunosignal increased with development. In deep layers, KCC2 immunolabeling was evenly distributed in plasma membrane and transport vesicles showing no obvious change with maturation. The number of KCC2 immunogold particles increased in dendritic spines with no association with synapses. This observation points to the dual role of KCC2 in spine genesis and ion cotransport. PMID:23420348

Kovács, Krisztina; Basu, Kaustuv; Rouiller, Isabelle; Sík, Attila

2014-03-01

305

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

PubMed

The purpose of this study was to evaluate the efficacy of Ca(OH)2 with or without a silver nanoparticle suspension to eliminate Enterococcus faecalis from root canals. A total of 66 extracted human single-rooted teeth contaminated with E.?faecalis were treated with 10% Ca(OH)2 alone, Ca(OH)2 with nanosilver or sterile water (as a negative control). Samples were obtained with paper points and Gates-Glidden burs at 1 and 7?days after root canal preparation and the number of colony-forming units (CFU) was determined. The number of CFUs observed after dressing with Ca(OH)2 ?+?nanosilver was significantly less than the number observed with Ca(OH)2 alone after 1 or 7?days (P??0.05). Higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7?days than 1?day (P?

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

2014-08-01

306

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

PubMed

Soil amendments can be used to cost-effectively reduce the bioavailability and mobility of toxic metals in contaminated soils. In this study a field demonstration was conducted at a Pb-contaminated site to evaluate the effectiveness of P-induced Pb immobilization. Phosphate was applied at a 4.0 molar ratio of P to Pb with three treatments: T1, 100% of P from H3PO4; T2, 50% P from H3PO4 + 50% P from Ca(H2PO4)2; and T3, 50% P from H3PO4 + 5% phosphate rock. Phosphate amendments effectively transformed soil Pb from the nonresidual (sum of exchangeable, carbonate, Fe/Mn, and organic) to the residual fraction, with residual Pb increase by 19-48% for T1, 22-50% for T2, and 11-55% for T3, respectively. Lead immobilization was attributed to the P-induced formation of chloropyromorphite [Pb10(PO4)6Cl2], which was identified in the surface soil, subsurface soil, and plant rhizosphere soil. Occurrence of chloropyromorphite was evident 220 days after P addition for T1 and T2 treatments and 330 days for T3. Visual MINTEQ model and activity-ratio diagram indicated that lead phosphate minerals controlled Pb2+ activities in the P-treated soils. Phosphate treatments significantly reduced Pb translocation from the roots to the shoots in the St. Augustine grass (Stenotaphrum secundatum), possibly via the formation of chloropyromorphite on the cell walls of roots. This field observation suggested that P amendments are efficient in reducing Pb mobility via in situ formation of insoluble chloropyromorphite minerals at a field setting. Lead immobilization shows a long-term stability. A mixture of H3PO4 and phosphate rock yields the best overall results for in situ Pb immobilization, with less soil pH change and less P leaching. Application of combined H3PO4 with phosphate rock may provide an effective alternative to the current phosphate remediation technologies for contaminated soils. PMID:12521153

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

2002-12-15

307

Determination of the forms of calcium present in coal chars by Ca K-edge XANES with Synchrotron Radiation  

E-print Network

This work is concerned with the Ca transformations during the pyrolysis of Ca(OH)2 or CaCO3-added coals. Ca K-edge X-ray absorption near edge structure (XANES) spectroscopy was applied to determine the forms of Ca in chars prepared from the pyrolysis of Ca-added coal. Results showed that Ca(OH)2 and CaSO4 existed in both the Ca(OH)2-added chars and the CaCO3-added chars, while CaS and CaO only existed in the chars prepared from the Ca(OH)2-added coal. Moreover, it was found that carboxyl Ca was formed during pyrolysis for either the Ca(OH)2-added coal or the CaCO3-added coals.

Liu, Lijuan; Cui, Mingqi; Hu, Yongfeng; Zheng, Lei; Zhao, Yidong; Ma, Chenyan; Xi, Shibo; Yang, Dongliang; Guo, Zhiying; Wang, Jie

2012-01-01

308

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

PubMed Central

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

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

2013-01-01

309

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

310

Unblocking the sink: improved CID-based analysis of phosphorylated peptides by enzymatic removal of the basic C-terminal residue.  

PubMed

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. PMID:24297471

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

2014-02-01

311

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

Microsoft Academic Search

A number of Li(Si)\\/FeS2 thermally activated batteries were developed for applications that require high reliability and a shelf life of twenty-five years. An accelerated aging study was undertaken to determine the feasibility of achieving the requirements. Deleterious chemical reactions were identified that could affect performance and reliability during the twenty-five year shelf life. The approach used was to accelerate the

J. Q. Searcy; P. A. Neiswander

1980-01-01

312

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

Microsoft Academic Search

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

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

2005-01-01

313

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

Microsoft Academic Search

A B S T R ACT Chloride-dependent K transport ((K-CI) cotransport) in dog red cells is activated by cell swelling. Whether the volume signal is generated by a change in cell configuration or by the dilution of some cytosolic constituent is not known. To differentiate between these two alternatives we prepared resealed ghosts that, compared with intact red cells, had

G. CRAIG COLCLASURE; JOHN C. PARKER

1992-01-01

314

Genetic Programming and Evolvable Machines, 11, 321338 (2010) W. B. LANGDON william.1angdon@kcl.ac.uk  

E-print Network

carried short reviews of a number of events.) We have also published an article on Internet onwards gives up to date statistics on the genetic programming and evolvable hardware literature, particularly, web pages, on-line resources, packages and products. We have reviewed 36 books, 10 edited

Fernandez, Thomas

315

Gutmann acceptor properties of LiCl, NaCl, and KCl buffered ambient-temperature chloroaluminate ionic liquids  

SciTech Connect

Ambient temperature chloroaluminate ionic liquids are an important class of nonaqueous solvents; they have been used in many process and show promise in high-energy density batteries. The properties of lithium chloride, sodium chloride, and potassium chloride buffered liquids are described.

Mantz, R.A.; Trulove, P.C.; Carlin, R.T. [North Carolina State Univ., Raleigh, NC (United States)] [North Carolina State Univ., Raleigh, NC (United States)

1997-03-12

316

Angiogenic growth factors augment K–Cl cotransporter expression in erythroid cells via hypoxia-inducible factor-1?  

PubMed Central

The potassium chloride cotransporters (KCC) family of proteins are widely expressed and are involved in the transepithelial movement of potassium and chloride ions and the regulation of cell volume. KCC activity is high in reticulocytes, and contributes to the dehydration of sickle red blood cells. Because plasma levels of both vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) are elevated in sickle cell individuals, and VEGF has been shown to increase KCC expression in other cells, we hypothesized that VEGF and PlGF influence KCC expression in erythroid cells. Both VEGF and PlGF treatment of human erythroid K562 cells increased both mRNA and protein levels of KCC1, KCC3b, and KCC4. VEGF- and PlGF-mediated cellular signaling involved VEGF-R1 and downstream effectors, specifically, PI-3 kinase, p38 MAP kinase, mTOR, NADPH-oxidase, JNK kinase, and HIF-1?. VEGF and PlGF-mediated transcription of KCC3b and KCC4 involved hypoxia response element (HRE) motifs in their promoters, as demonstrated by promoter analysis, EMSA and ChiP. These results were corroborated in vivo by adenoviral-mediated overexpression of PlGF in normal mice, which led to increased expression of mKCC3 and mKCC4 in erythroid precursors. Our studies show that VEGF and PlGF regulate transcription of KCC3b and KCC4 in erythroid cells via activation of HIF-1?, independent of hypoxia. These studies provide novel therapeutic targets for regulation of cell volume in RBC precursors, and thus, amelioration of dehydration in RBCs in sickle cell disease. Am. J. Hematol. 89:273–281, 2014. © 2013 Wiley Periodicals, Inc. PMID:24227191

Gonsalves, Caryn S; Crable, Scott; Chandra, Sharat; Li, Wei; Kalra, Vijay K; Joiner, Clinton H

2014-01-01

317

Cellular expression of the K+-Cl- cotransporter KCC3 in the central nervous system of mouse.  

PubMed

Potassium/Chloride cotransporters are transmembrane proteins that regulate cell volume and control neuronal activity by transporting K(+) and Cl(-) ions across the plasma membrane. Potassium/Chloride cotransporter 3 (KCC3) mutations are responsible for hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC), which is a severe sensory and motor neuropathy. Two major splice variants, KCC3a and KCC3b, were shown to be expressed in adult mouse tissues. Although KCC3a is mainly expressed in the central nervous system (CNS), its specific cellular expression patterns have not been determined. Here, we used an approach combining in situ hybridization and immunohistochemical techniques to determine the cellular expression of KCC3 in the mouse CNS and showed that KCC3 is mainly expressed in neurons, including a subpopulation of interneurons. Finally, we showed that some non-neuronal cells, such as radial glial-like cells in the spinal cord, also express KCC3. PMID:21147077

Shekarabi, Masoud; Salin-Cantegrel, Adèle; Laganière, Janet; Gaudet, Rébecca; Dion, Patrick; Rouleau, Guy A

2011-02-16

318

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

319

Anodic process of electrorefining spent nuclear fuel in molten LiCl-KCL-UCl{sub 3}/CD system.  

SciTech Connect

This article summarizes the experimental results and engineering aspects regarding the anodic process for electrorefining 100 irradiated driver fuel assemblies, a demonstration project for the Department of Energy (DOE) to treat spent nuclear fuel. The focus is on the anode due to its unique geometry (fuel dissolution baskets loaded with chopped irradiated fuel segments), complex chemical compositions, highly demanding process goals and their significance to the entire spent fuel treatment process. Chemical analysis results of cladding hull samples were used as the key criteria to evaluate the effectiveness of the uranium dissolution and noble metal retention. Parametric study indicated that the diffusion of reactants in the porous fuel matrix was the rate-controlling step to the uranium dissolution from the chopped fuel segments. Anode resistance was the most effective parameter to assess the completeness of uranium dissolution and noble metal retention.

Li, S. X.

2002-07-03

320

A study on the recovery of actinide elements from molten LiCl–KCl eutectic salt by an electrochemical separation  

Microsoft Academic Search

Pyroprocessing is a prominent way for the recovery of the long-lived elements from the spent nuclear fuel. Electrorefining is a key technology for pyroprocessing and generally composed of two recovery steps—deposition of uranium onto a solid cathode and the recovery of TRU (TRansUranic) elements. In this study, it was investigated on electrochemical separation of actinides to develop an actinide recovery

Sang Woon Kwon; Do Hee Ahn; Eung Ho Kim; Ho Geun Ahn

2009-01-01

321

A Reduced Polyoxomolybdenum Borophosphate Anion Related to the Wells-Dawson Clusters  

E-print Network

are organically templated three-dimensional structures such as MII[B2P3O12(OH)],enH2 (M ) Co, Mn, Fe, Cu, Zn, Ni3N2H4, H3PO4, HCl, and H2O, in the molar ratio 1:0.13:1.67:3:3.33:1:74 (pH 1.5), heated for 5 days at 165 °C under autogenous pressure in a Teflon-lined autoclave. Dark blue polyhedral crystals of 1 were

322

Catalytic effects of eight inorganic additives on pyrolysis of pine wood sawdust by microwave heating  

Microsoft Academic Search

In this paper, pyrolysis of pine wood sawdust was carried out by microwave heating at ca. 470°C under dynamic nitrogen atmosphere. Eight inorganic additives (NaOH, Na2CO3, Na2SiO3, NaCl, TiO2, HZSM-5, H3PO4, Fe2(SO4)3) were investigated in terms of their catalytic effects on the pyrolysis. All of the eight additives have increased yields of solid products greatly and decreased yields of gaseous

Ming-qiang Chen; Jun Wang; Ming-xu Zhang; Ming-gong Chen; Xi-feng Zhu; Fan-fei Min; Zhi-cheng Tan

2008-01-01

323

Defect selective etching of GaAsyP1-y photovoltaic materials  

NASA Astrophysics Data System (ADS)

Rapid and accurate threading dislocation density (TDD) characterization of direct-gap GaAsyP1-y photovoltaic materials using molten KOH defect selective etching (DSE) is demonstrated. TDDs measured using molten KOH DSE show close agreement with those from both electron beam-induced current mapping and planar view transmission electron microscopy, provided TDD<107 cm-2. H3PO4 DSE is also demonstrated as an accurate method for characterizing TDD of GaP substrates. Taken together, the DSE methods described here enable TDD characterization over large areas (>105 ?m2) from substrate to GaAsyP1-y device layer.

Yaung, Kevin Nay; Tomasulo, Stephanie; Lang, Jordan R.; Faucher, Joseph; Lee, Minjoo Larry

2014-10-01

324

Galvanic corrosion effects in InP-based laser ridge structures  

Microsoft Academic Search

Galvanic corrosion effects in metallized III-V laser structures have been studied. Small gaps present in the metallization\\u000a can leave exposed semiconductor regions, which are susceptible to localized corrosion in the presence of an electrolyte. Electochemical\\u000a measurements in two different electrolytes, i.e., 1% HF and concentrated H3PO4, were made of test structures comprised of n-type InP, p-type InP, and p-type InGaAs,

D. G. Ivey; J. Luo; S. Ingrey; R. Moore; I. Woods

1998-01-01

325

Solvent-free synthesis, spectral correlations and antimicrobial activities of some aryl E 2-propen-1-ones  

NASA Astrophysics Data System (ADS)

Totally 38 aryl E 2-propen-1-ones including nine substituted styryl 4-iodophenyl ketones have been synthesised using solvent-free SiO2-H3PO4 catalyzed Aldol condensation between respective methyl ketones and substituted benzaldehydes under microwave irradiation. The yields of the ketones are more than 80%. The synthesised chalcones were characterized by their analytical, physical and spectroscopic data. The spectral frequencies of synthesised substituted styryl 4-iodophenyl ketones have been correlated with Hammett substituent constants, F and R parameters using single and multi-linear regression analysis. The antimicrobial activities of 4-iodophenyl chalcones have been studied using Bauer-Kirby method.

Sathiyamoorthi, K.; Mala, V.; Sakthinathan, S. P.; Kamalakkannan, D.; Suresh, R.; Vanangamudi, G.; Thirunarayanan, G.

2013-08-01

326

Solvent-free synthesis, spectral correlations and antimicrobial activities of some aryl E 2-propen-1-ones.  

PubMed

Totally 38 aryl E 2-propen-1-ones including nine substituted styryl 4-iodophenyl ketones have been synthesised using solvent-free SiO2-H3PO4 catalyzed Aldol condensation between respective methyl ketones and substituted benzaldehydes under microwave irradiation. The yields of the ketones are more than 80%. The synthesised chalcones were characterized by their analytical, physical and spectroscopic data. The spectral frequencies of synthesised substituted styryl 4-iodophenyl ketones have been correlated with Hammett substituent constants, F and R parameters using single and multi-linear regression analysis. The antimicrobial activities of 4-iodophenyl chalcones have been studied using Bauer-Kirby method. PMID:23673243

Sathiyamoorthi, K; Mala, V; Sakthinathan, S P; Kamalakkannan, D; Suresh, R; Vanangamudi, G; Thirunarayanan, G

2013-08-01

327

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 0.1-1mgkg(-1) with LOD 30µgkg(-1). The sample throughput was 4h(-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

328

Effect of duration on pore widening of one-step anodized aluminum oxide template  

NASA Astrophysics Data System (ADS)

This work investigated the effect of pore widening for fabrication of anodized aluminum oxide (AAO) template. AAO template was fabricated using one-step anodization method. The influence of H3PO4 on the widening of pore of AAO was investigated. The morphology of AAO was analyzed using FESEM. Result shows that by widening the pores at 25°C can help to protect the neighbouring pores from any damage. Single, well separated, straight without any tilt or branches, well aligned and controllable pore diameter could be obtained using this technique.

Saidin, Nur Ubaidah; Jumali, Mohammad Hafizuddin Hj; Ying, Kok Kuan

2014-09-01

329

31P and 27Al NMR studies of aqueous (2-hydroxyethyl) trimethylammonium solutions containing aluminum and phosphorus  

Microsoft Academic Search

Phosphorus-31 and aluminum-27 nuclear magnetic resonance techniques have been used to characterize the distribution of soluble aluminophosphate species in aqueous solutions of (2-hydroxyethyl) trimethylammonium chloride (2-HETMACl), phosphoric acid, and aluminum sulfate. Soluble aluminophosphate cations obtain from reactions of hexaaqua aluminum cations [A1(H2O)6]3+, with phosphate ligands (i.e., H3PO4, H2PO4–, and acid dimers H6P2O8 and H5P2O7–). 31P NMR and 27Al NMR spectroscopies

Abdolraouf Samadi-Maybodi; S. Karim Hassani Nejad-Darzi; Hamidreza Bijanzadeh

2009-01-01

330

Sequential-refining of crude glycerol derived from waste used-oil methyl ester plant via a combined process of chemical and adsorption  

Microsoft Academic Search

A sequential stage physico-chemical refining of crude glycerol, derived from a waste used-oil utilizing biodiesel (methyl ester) production plant, was performed by acidification, polar solvent extraction and activated carbon adsorption at a laboratory scale and ambient temperature. The effect of varying the acid type (H3PO4, H2SO4 and CH3COOH) and pH (1–6), the type of polar solvent (CH3OH, C2H5OH and C3H7OH)

Rudemas Manosak; Siripong Limpattayanate; Mali Hunsom

2011-01-01

331

Chlorpheniramine dissolution and relative urinary excretion from commercial products.  

PubMed

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

Hsu, H Y; Ayres, J W

1989-10-01

332

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

333

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

334

Epoxidation of 1,4-bis(allyloxy)butane by hydrogen peroxide using phase transfer catalysis  

Microsoft Academic Search

Epoxidation of 1,4-bis(allyloxy)butane by hydrogen peroxide under phase transfer catalysis and transition metal salts was investigated. The most advantageous conditions for the epoxidation were determined (temperature, reaction time, the type and amount of phase transfer catalyst, molar ratio of hydrogen peroxide to 1,4-bis(allyloxy)butane, the amount and molar ratio of H3PO4:Na2WO4·2H2O). The process was evaluated in terms of the conversion of

E. Kaczmarczyk; E. Janus; E. Milchert

2006-01-01

335

Synthesis and Crystal Structure of the Octahedral-Tetrahedral Framework Indium Phosphate Cs[In2(PO4)(HPO4)2(H2O)2  

Microsoft Academic Search

The reaction of InCl3, H3PO4, CsVO3, TMAOH (tetramethyl ammonium hydroxide), and H2O in the molar ratios 2:6:1:1:125 under hydrothermal conditions at 200°C for 2 days yielded pale yellow crystals of Cs[In2(PO4)(HPO4)2(H2O)2] (1). Phosphate (1) crystallizes in the monoclinic space group P 21\\/c (No. 14) with a = 6.580(2) Å, b = 18.092(1) Å, c = 10.180(1) Å beta = 97.92(2)°,

Sandeep S. Dhingra; Robert C. Haushalter

1994-01-01

336

Flexible solid-state supercapacitors based on carbon nanoparticles/MnO2 nanorods hybrid structure.  

PubMed

A highly flexible solid-state supercapacitor was fabricated through a simple flame synthesis method and electrochemical deposition process based on a carbon nanoparticles/MnO(2) nanorods hybrid structure using polyvinyl alcohol/H(3)PO(4) electrolyte. Carbon fabric is used as a current collector and electrode (mechanical support), leading to a simplified, highly flexible, and lightweight architecture. The device exhibited good electrochemical performance with an energy density of 4.8 Wh/kg at a power density of 14 kW/kg, and a demonstration of a practical device is also presented, highlighting the path for its enormous potential in energy management. PMID:22182051

Yuan, Longyan; Lu, Xi-Hong; Xiao, Xu; Zhai, Teng; Dai, Junjie; Zhang, Fengchao; Hu, Bin; Wang, Xue; Gong, Li; Chen, Jian; Hu, Chenguo; Tong, Yexiang; Zhou, Jun; Wang, Zhong Lin

2012-01-24

337

Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors.  

PubMed

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. PMID:24975864

Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

2014-08-01

338

Crystallographic wet chemical etching of GaN  

NASA Astrophysics Data System (ADS)

We demonstrate well-controlled crystallographic etching of wurtzite GaN grown on c-plane sapphire using H3PO4, molten KOH, KOH dissolved in ethylene glycol, and NaOH dissolved in ethylene glycol between 90 and 180 °C, with etch rates as high as 3.2 ?m/min. The crystallographic GaN etch planes are {0001}, {101¯0}, {101¯ 1¯}, {101¯ 2¯}, and {101¯3}. The vertical {101¯0} planes appear perfectly smooth when viewed with a field-effect scanning electron microscope. The activation energy is 21 kcal/mol, indicative of reaction-rate limited etching.

Stocker, D. A.; Schubert, E. F.; Redwing, J. M.

1998-11-01

339

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

PubMed

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

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

2012-02-01

340

Thermochemical energy storage for a lunar base  

Microsoft Academic Search

A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO\\/H2O system is capable of generating electric power during both the day and night. Mass of the required amount of CaO is neglected

Marla E. Perez-Davis; Barbara I. McKissock; Frank Difilippo

1992-01-01

341

Development of a galvanic sensor system for detecting the corrosion damage of the steel embedded in concrete structures: Part 1. Laboratory tests to correlate galvanic current with actual damage  

Microsoft Academic Search

The correlation between sensor output and corrosion rate of reinforcing steel was evaluated by laboratory electrochemical tests in saturated Ca(OH)2 with 3.5 wt.% NaCl. In this paper, two types of electrochemical probes were developed: galvanic cells containing of steel\\/copper and steel\\/stainless steel couples. The corrosion behavior in saturated Ca(OH)2 solution with and without 3.5 wt.% NaCl addition for the different

Ji-Hong Yoo; Zin-Taek Park; Jung-Gu Kim; Lan Chung

2003-01-01

342

The effect of calcium hydroxide on solubilisation of bio-active dentine matrix components  

Microsoft Academic Search

Calcium hydroxide (Ca(OH)2) has been used extensively to induce dentine regeneration through formation of dentine bridges at sites of pulp exposure after dental tissue injury, however, the biological processes underpinning these events are unclear. We hypothesise that growth factors and other bio-active molecules, sequestered within dentine matrix, may be released by the action of Ca(OH)2 and signal gene expression in

Lee Graham; Paul R. Cooper; Nicola Cassidy; Jacques E. Nor; Alastair J. Sloan; Anthony J. Smith

2006-01-01

343

Effects of slag and cooling method on the progressive deterioration of concrete after exposure to elevated temperatures as in a fire event  

Microsoft Academic Search

In the present work OPC and OPC\\/slag concretes were exposed to elevated temperatures, 400 and 800°C. The critical temperature\\u000a of 400°C has been reported for OPC paste. Above 400°C, the paste hydrate Ca(OH)2 dehydrates into CaO causing the OPC paste to shrink and crack. After cooling and in the presence of air moisture, CaO rehydrates\\u000a into Ca(OH)2, resulting in disintegration

Alessandra Mendes; Jay G. Sanjayan; Frank Collins

2011-01-01

344

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

345

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

PubMed

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

Lu, Qiang; Ye, Xiao-Ning; Zhang, Zhi-Bo; Dong, Chang-Qing; Zhang, Ying

2014-11-01

346

Electrostatic modification of oxide semiconductors by electric double layers of microporous SiO2-based solid electrolyte  

NASA Astrophysics Data System (ADS)

We have studied electrostatic modulation of InGaZnO4 and indium-tin oxide (ITO) channel by using microporous SiO2-based solid electrolyte as gate dielectrics in the field-effect transistors (FETs) structure. H3PO4-treated SiO2-based solid electrolyte was found to be have a large capacitance (9.5 ?F/cm2) due to the strong capacitive coupling by electric double layer(EDL) between H3PO4-treated solid electrolyte and active channel. High carrier densities (>1014/cm2) and large metallic conductivities (2180 S/cm) in InGaZnO4 channel were electrostatically induced, while a metal-to-insulator transition (more than 6 orders of magnitude of channel resistance modulation) was observed in ITO channel by using such FET structure. Furthermore, device simulation based on an EDL model can also reproduce the transfer characteristics well. Our result provides a new opportunity for electrostatic modulation of the electronic properties in condensed matter.

Jiang, Jie; Dai, Minzhi; Sun, Jia; Zhou, Bin; Lu, Aixia; Wan, Qing

2011-03-01

347

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

348

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

PubMed

This work presents the experimental kinetic data and the fractal modeling of sugarcane bagasse steam treatment and enzymatic hydrolysis. Sugarcane bagasse (50 wt% moisture) was pretreated by autohydrolysis at 210 °C for 4 min. Acid catalysis involved the use of 9.5mg g(-1) of H2SO4 or H3PO4 in relation to the substrate dry mass at these same pretreatment conditions. Unwashed, water-washed and alkali-washed substrates were hydrolyzed at 2.0 wt% using 8 and 15 FPU g(-1) (108.22 and 199.54 mg/g) total solids of a Celluclast 1.5 L and Novozym 188 mixture (Novozymes). The fractal kinetic modeling was used to describe the effect of pretreatment and both washing processes on substrate accessibility. Water and/or alkali washing was not strictly necessary to achieve high hydrolysis efficiencies. Also, the fractal model coefficients revealed that H3PO4 was a better pretreatment catalyst under the experimental conditions used in this study, resulting in the most susceptible substrates for enzymatic hydrolysis. PMID:24007721

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

2013-11-01

349

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

350

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

351

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

PubMed

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

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

2012-01-15

352

Relative effect of different inorganic acids on selective enrichment of acidogenic biocatalyst for fermentative biohydrogen production from wastewater.  

PubMed

The effect of different inorganic acids viz., HNO3, HCl, H2SO4 and H3PO4 on inoculum pretreatment to selectively enrich hydrogen (H2) producing acidogenic bacteria was evaluated in anaerobic sequencing batch bioreactors. Relative positive efficiency of HNO3 pretreated consortia in enhancing H2 production (11.85 mol H2/kg CODR) was noticed compared to other acids (HCl, 5.64 mol H2/kg CODR; H2SO4, 7.65 mol H2/kg CODR; H3PO4, 6.90 mol H2/kg CODR) and untreated-parent consortia (control, 6.80 mol H2/kg CODR). On the contrary, substrate degradation (COD removal) was higher with the control operation (?COD, 66.3%; substrate degradation rate (SDR), 1.42 kg CODR/m(3)-day) compared to pre-treated culture. HNO3 pre-treatment resulted in a shift in the fermentation pathway towards more acetic acid production, while other acid pretreatment and untreated culture showed mixed type fermentation (acetic, butyric, propionic acids). The bio-electrochemical analysis and dehydrogenase activity supported the biocatalyst performance after HNO3 pretreatment with specific enrichment of Firmicutes and Bacillus. PMID:24001561

Sarkar, Omprakash; Goud, R Kannaiah; Subhash, G Venkata; Mohan, S Venkata

2013-11-01

353

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

354

Xylose reductase and xylitol dehydrogenase activities of Candida guilliermondii as a function of different treatments of sugarcane bagasse hemicellulosic hydrolysate employing experimental design.  

PubMed

The sugarcane bagasse hydrolysate, which is rich in xylose, can be used as culture medium for Candida guilliermondii in xylitol production. However, the hydrolysate obtained from bagasse by acid hydrolysis at 120 degrees C for 20 min has by-products (acetic acid and furfural, among others), which are toxic to the yeast over certain concentrations. So, the hydrolysate must be pretreated before using in fermentation. The pretreatment variables considered were: adsorption time (15,37.5, and 60 min), type of acid used (H2So4 and H3Po4), hydrolysate concentration (original, twofold, and fourfold concentrated), and active charcoal (0.5, 1.75 and 3.0%). The suitability of the pretreatment was followed by measuring the xylose reductase (XR) and xylitol dehydrogenase (XD) activity of yeast grown in each treated hydrolysate. The response surface methodology (2(4) full factorial design with a centered face) indicated that the hydrolysate might be concentrated fourfold and the pH adjusted to 7.0 with CaO, followed by reduction to 5.5 with H3PO4. After that it was treated with active charcoal (3.0%) by 60 min. This pretreated hydrolysate attained the high XR/XD ratio of 4.5. PMID:12018268

Alves, Lourdes A; Vitolo, Michele; Felipe, Maria das Graças A; de Almeida e Silva, João Batista

2002-01-01

355

Synthesis and in vitro degradation of a novel magnesium oxychloride cement.  

PubMed

Magnesium oxychloride cement (MOC) has been used in civil engineering as it exhibits a relatively high early strength and a low coefficient of thermal expansion. Its poor water resistance, although, has prevented its widespread use. Steady degradation when immersed in an aqueous environment, however, could be a beneficial property for a resorbable bone replacement. In this study, we have evaluated how different concentrations of phosphoric acid may be used to enhance water resistance providing some control over the rate of degradation. The phase compositions, microstructures, mechanical properties, and the degradation of MOC have been evaluated. As a preliminary assessment of biological suitability, the response of a population of bone marrow stromal cells to the surface was evaluated. X-ray diffraction data demonstrate that 5Mg(OH)2 ·MgCl2 ·8H2 O (phase 5) was formed in all MOC samples. The MOC modified with H3 PO4 exhibits good water resistance and can sustain strength in aqueous medium and by adjusting H3 PO4 concentration; degradation speed may be controlled. Cells cultured on the surface of the MOC attached and retained viability over the duration of the study. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 194-202, 2015. PMID:24623713

Tan, Yanni; Liu, Yong; Zhao, Zhongwei; Paxton, Jennifer Z; Grover, Liam M

2015-01-01

356

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

357

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

358

Digital image-based titrations.  

PubMed

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

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

2006-06-16

359

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

360

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

PubMed

Direct spreading on agricultural lands may represent an environmentally friendly disposal method and a possible use of water and nutrients from olive mill wastewaters (OMWs). However, the agronomic use of OMWs is limited, among others by polyphenols, which exert phytotoxic effects. Activated charcoal (AC) has been recognized as a very effective agent for polyphenol abatement, as it enables an irreversible process of phenol adsorption. Addition of calcium hydroxide (Ca(OH)2) has also been described as a cheap and effective method in polyphenols abatement. However, the effects of Ca(OH)2 addition to OMW on seed germination are unclear. In this paper, the effects of AC and/or Ca(OH)2 on OMW polyphenols abatement, and Lolium multiflorum seed germination have been investigated. The highest polyphenols removal, approximately 95%, was observed when 80 g L(-1) of AC was added to OMWs (the maximum dose in this investigation). The addition of Ca(OH)2 not only improved the effectiveness of the AC treatment but also resulted in a significant rise in Lolium seed germination at the highest AC doses (60 and 80 g L(-1)). Considering the high salinity (7300 ?S cm(-1)) of these wastewaters, low quantities of Ca(OH)2 may also exert a protective effect on soil structure counteracting the sodium-induced dispersion through the binding action of calcium cation on clays and organic matter. PMID:24289894

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

2014-04-01

361

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

PubMed Central

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

Elsaka, Shaymaa Elsayed; Elnaghy, Amr Mohamed

2012-01-01

362

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

363

Reversible inhibition/activation of olefin metathesis: a kinetic investigation of ROMP and RCM reactions with Grubbs' catalyst.  

PubMed

The metathesis activity of Grubbs' catalyst 1 was investigated in the presence of N-donor ligands (1-methylimidazole [MIM], 4-(N,N-dimethylamino)pyridine [DMAP], pyridine, and 1-octylimidazole [OIM]). Ring opening metathesis polymerization (ROMP) reactions of cyclooctene (COE), bulk-ROMP reactions of COE and norbornadiene (NBD), and ring closing metathesis (RCM) reactions of diethyl diallylmalonate (DEDAM) were conducted containing various equivalents of N-donor with respect to catalyst. ROMP reactions could be stopped using MIM (1-5 equiv) and DMAP (2-5 equiv), and slowed with pyridine (1-5 equiv) by factors >100, in benzene solution for 24 h. The stopped reactions could be initiated with excess phosphoric acid (H3PO4), and the reactions proceeded faster than with uninhibited Grubbs' catalyst in the first 4 min after reactivation. Thereafter, the reaction proceeded at the same rate as the reaction with the uninhibited catalyst. ROMP reactions in neat COE and NBD could be inhibited for 72 h using 2 equiv of MIM, DMAP, or OIM and activated with H3PO4 to give polymer gels within minutes or less. RCM reactions could be completely inhibited with MIM (1-5 equiv), but upon treatment with H3PO4, the reaction would proceed at a fraction of the initial rate accomplished by uninhibited Grubbs' catalyst 1. A structural investigation of the inhibited species showed that MIM and DMAP completely or partially transform catalyst 1 into the hexacoordinate species 5a or 5b producing free PCy3, which additionally acts as an inhibitor for the ROMP reaction. Upon reactivation, the PCy3 is protonated along the N-donor ligand; however, over the period of 5 min, the phosphine has been found to coordinate back to the ruthenium catalyst. Therefore, the reaction slows to the same polymerization rate as the reaction using the uninhibited catalyst at this point. Complexes 5a and 5b were isolated, characterized, and employed in ROMP and RCM experiments where they exhibited very low catalytic activity. PMID:17963379

P'Pool, Steven J; Schanz, Hans-Jörg

2007-11-21

364

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

365

Further optimization of the K-Cl cotransporter KCC2 antagonist ML077: Development of a highly selective and more potent in vitro probe  

PubMed Central

Further chemical optimization of the MLSCN/MLPCN probe ML077 (KCC2 IC50 = 537 nM) proved to be challenging as the effort was characterized by steep SAR. However, a multidimensional iterative parallel synthesis approach proved productive. Herein we report the discovery and SAR of an improved novel antagonist (VU0463271) of the neuronal-specific potassium-chloride cotransporter 2 (KCC2), with an IC50 of 61 nM and >100-fold selectivity versus the closely related Na-K-2Cl cotransporter 1 (NKCC1) and no activity in a larger panel of GPCRs, ion channels and transporters. PMID:22727639

Delpire, Eric; Baranczak, Aleksandra; Waterson, Alex G.; Kim, Kwangho; Kett, Nathan; Morrison, Ryan D.; Daniels, J. Scott; Weaver, C. David; Lindsley, Craig W.

2012-01-01

366

N-methyl-D-aspartate receptor- and calpain-mediated proteolytic cleavage of K+-Cl- cotransporter-2 impairs spinal chloride homeostasis in neuropathic pain.  

PubMed

Loss of synaptic inhibition by ?-aminobutyric acid and glycine due to potassium chloride cotransporter-2 (KCC2) down-regulation in the spinal cord is a critical mechanism of synaptic plasticity in neuropathic pain. Here we present novel evidence that peripheral nerve injury diminishes glycine-mediated inhibition and induces a depolarizing shift in the reversal potential of glycine-mediated currents (E(glycine)) in spinal dorsal horn neurons. Blocking glutamate N-methyl-D-aspartate (NMDA) receptors normalizes synaptic inhibition, E(glycine), and KCC2 by nerve injury. Strikingly, nerve injury increases calcium-dependent calpain activity in the spinal cord that in turn causes KCC2 cleavage at the C terminus. Inhibiting calpain blocks KCC2 cleavage induced by nerve injury and NMDA, thereby normalizing E(glycine). Furthermore, calpain inhibition or silencing of ?-calpain at the spinal level reduces neuropathic pain. Thus, nerve injury promotes proteolytic cleavage of KCC2 through NMDA receptor-calpain activation, resulting in disruption of chloride homeostasis and diminished synaptic inhibition in the spinal cord. Targeting calpain may represent a new strategy for restoring KCC2 levels and tonic synaptic inhibition and for treating chronic neuropathic pain. PMID:22854961

Zhou, Hong-Yi; Chen, Shao-Rui; Byun, Hee-Sun; Chen, Hong; Li, Li; Han, Hee-Dong; Lopez-Berestein, Gabriel; Sood, Anil K; Pan, Hui-Lin

2012-09-28

367

Magnetic treatment of aqueous solutions of CaCl 2 , MgCl 2 , KCl, NaCl, CaSO 4 , and MgSO 4  

Microsoft Academic Search

The intensity of the magnetic field in the effective zone of the apparatus during the experiments did not exceed 7. 104 A\\/m, and the rate of motion of the solution was 0.5 m\\/see. The structural changes of the aqueous solutions resulting from their \\

A. I. Shakhov; M. V. Reznik; S. S. Dushkin; A. S. Avetisov

1971-01-01

368

Single-Stage Extraction Test with Continuous Flow of Molten LiCl-KCl Salt and Liquid Cd for Pyro-Reprocessing of Metal FBR Fuel  

Microsoft Academic Search

A single-stage extraction test with the continuous flow of both molten salt and liquid Cd was carried out as a preliminary step of the development of a multistage countercurrent extraction process for the pyrometallurgical reprocessing of metal FBR fuel. Ce, Gd, and Y were selected as the substitutes for U, other actinides, and rare-earth elements, respectively. More than 97% of

Kensuke KINOSHITA; Takeshi TSUKADA; Takanari OGATA

2007-01-01

369

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

Microsoft Academic Search

A new chlorination method using ZrCl4 in a molten salt bath has been investigated for the pyrometallurgical reprocessing of nuclear fuels. ZrCl4 has a high reactivity with oxygen but is not corrosive to refractory metals such as steel. Rare earth oxides (La2O3, CeO2, Nd2O3 and Y2O3) and actinide oxides (UO2 and PuO2) were allowed to react with ZrCl4 in a

Yoshiharu Sakamura; Tadashi Inoue; Takashi Iwai; Hirotake Moriyama

2005-01-01

370

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

Microsoft Academic Search

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

S. Frank

2009-01-01

371

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

372

Thermochemical energy storage for a lunar base  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

373

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

374

Multi-silicon ridge nanofabrication by repeated edge lithography  

NASA Astrophysics Data System (ADS)

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 H3PO4 acid SiNx retraction etching, 20% KOH Si etching, 50% HF SiNx retraction etching and LOCal Oxidation of Silicon (LOCOS). Si nanoridges with smooth vertical sidewalls are fabricated by using Si lang110rang 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.

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

2009-08-01

375

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

376

Effective elimination of isobaric ions interference and precise thermal ionization mass spectrometer analysis for boron isotope  

NASA Astrophysics Data System (ADS)

An ionization depressor, 1% H3PO4 was used to eliminate the isobaric interference that has been of a great concern during the procedure of boron isotopic ratio analysis by thermal ionization mass spectrometer (TIMS). Our experiments have shown that it appears to be an effective method to completely restrain the formation of isobaric ions of CNO- and Cs2CNO+ in the ionization source of mass spectrometer. We have also discussed the optimum proportion of depressor to nitrite for precise analysis of boron isotopes in natural samples based on a conditional experiment. In this case, the pretreatment of boron extraction from natural samples is greatly simplified since it is not necessary to remove nitrite and organic matter completely. In virtue of the method, we determined boron isotope in different types of natural samples, and our results are consistent with previous reports.

Wei, Haizhen; Xiao, Yingkai; Sun, Aide; Zhang, Chonggeng; Li, Shizhen

2004-07-01

377

Phosphoric acid loaded azo (-N?N-) based covalent organic framework for proton conduction.  

PubMed

Two new chemically stable functional crystalline covalent organic frameworkds (COFs) (Tp-Azo and Tp-Stb) were synthesized using the Schiff base reaction between triformylphloroglucinol (Tp) and 4,4'-azodianiline (Azo) or 4,4'-diaminostilbene (Stb), respectively. Both COFs show the expected keto-enamine form, and high stability toward boiling water, strong acidic, and basic media. H3PO4 doping in Tp-Azo leads to immobilization of the acid within the porous framework, which facilitates proton conduction in both the hydrous (? = 9.9 × 10(-4) S cm(-1)) and anhydrous state (? = 6.7 × 10(-5) S cm(-1)). This report constitutes the first emergence of COFs as proton conducting materials. PMID:24758195

Chandra, Suman; Kundu, Tanay; Kandambeth, Sharath; Babarao, Ravichandar; Marathe, Yogesh; Kunjir, Shrikant M; Banerjee, Rahul

2014-05-01

378

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 (0.25w/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

379

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

NASA Astrophysics Data System (ADS)

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.

di, Dawei; Perez-Wurfl, Ivan; Gentle, Angus; Kim, Dong-Ho; Hao, Xiaojing; Shi, Lei; Conibeer, Gavin; Green, Martin A.

2010-11-01

380

High-performance liquid chromatographic separation of iodoamino acids for tracer turnover studies of thyroid hormones in vivo.  

PubMed

A reversed-phase high-performance liquid chromatographic technique was developed to separate radioiodinated thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3) and two diiodothyronines (3,3'-T2 and 3',5'-T2), in extracts from either serum or urine. Chromatography was performed with 10-micron C18 silica gel, packed in a glass column (3 X 300 mm); the mobile phase was methanol-water (55:45) adjusted to pH 3 with H3PO4, at a flow-rate of 1.2 ml/min and a pressure of 2800 p.s.i. The results demonstrate the ability of the system to yield a clear-cut separation of the iodothyronines involved in in vivo turnover studies, i.e., T4, T3, rT3, and the two T2 compounds together. PMID:6490771

Bianchi, R; Molea, N; Cazzuola, F; Fusani, L; Lotti, M; Bertelli, P; Ferdeghini, M; Mariani, G

1984-08-01

381

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

382

Synthesis and structural characterisation using Rietveld and pair distribution function analysis of layered mixed titanium-zirconium phosphates  

NASA Astrophysics Data System (ADS)

Crystalline metal (IV) phosphates with variable zirconium-to-titanium molar ratios of general formula (Ti 1- xZr x)(HPO 4) 2·H 2O have been prepared by precipitation of soluble salts of the metals with phosphoric acid and heating the amorphous solids in 12 M H 3PO 4 in an autoclave. The new materials are structurally characterised by Rietveld analysis of synchrotron X-ray powder diffraction data and pair distribution function (PDF) analysis of high energy synchrotron X-ray total scattering data. A broad range of zirconium-titanium phosphate solid solutions were formed showing isomorphous substitution of titanium by zirconium in the ?-titanium phosphate lattice and vice versa for titanium substitution into the ?-zirconium phosphate lattice. In both cases the solubility is partial with the coexistence of two substituted phases observed in samples with nominal compositions between the solubility limits.

Burnell, Victoria A.; Readman, Jennifer E.; Tang, Chiu C.; Parker, Julia E.; Thompson, Stephen P.; Hriljac, Joseph A.

2010-09-01

383

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

384

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

385

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

NASA Astrophysics Data System (ADS)

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. It was found in both cases that LAP affects the growth morphology and other properties. The properties of resulting crystals in terms of growth morphology, optical and mechanical properties are presented and discussed.

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

2005-08-01

386

Investigation of the GaAs-pyramids overgrowth using MOCVD  

NASA Astrophysics Data System (ADS)

In this work, the epitaxial overgrowth of high and smooth GaAs mesas is presented. GaAs mesas of sidewall slope 35°, 40°, 45°, and 55° were first prepared by wet-chemical etching in H 3PO 4, H 2O 2, H 2O based solution. Then the metallorganic chemical vapour deposition was used for the mesas overgrowth. The influence of the growth conditions—temperature, V/III ratio, and growth rate—on the mesa-sidewall morphology was studied using optical microscopy, scanning electron microscopy and atomic force microscopy. We show that the sidewall quality is very high for all mesa slopes for growth rate 0.6 ?m/h, V/III ratio 383, and growth temperature 640°C. Grown structures reveal strong tendency for faceting into {1 1 0} crystallographic planes.

Gregušová, D.; Cambel, V.; Kúdela, R.; Šolt?s, J.; Kostiè, I.; Attolini, G.; Pelosi, C.

2003-02-01

387

Formation of micro- and nano-striations at (211)A facets during wet etching of InP in HCl  

NASA Astrophysics Data System (ADS)

It is generally observed that the anisotropic wet etching of InP crystal in HCl-based etchants leads to the spontaneous formation of nano-sized striations at certain side facets of patterned objects. It is the consequence of mask edge fluctuation linked with the specific dissolution mechanism of InP in HCl. This paper reports on the formation of striations at (211)A-related facets of [01¯1]-oriented mesa patterns in (100) InP during etching in 3HCl:1H 3PO 4. It is shown that if artificial fluctuation is introduced in the form of regular corrugations along [01¯1]-oriented mask pattern edges, it is possible to form uniform regularly-spaced micro-sized or nano-sized sharp-edged striations in the (211)A-related facets. The formation of such "artificial" striations is investigated using SEM and AFM.

Eliáš, P.; Šoltýs, J.; Kosti?, I.

2004-07-01

388

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

389

Environmentally friendly epoxidation of olefins under phase-transfer catalysis conditions with hydrogen peroxide  

Microsoft Academic Search

Several catalysis systems, WO3?H2O\\/H2O2–H2O–H3O+\\/Q+A?\\/H3PO4\\/H2SO4\\/solvent (Q+A? = Arquad 2HT®, [CH3(n-C8H17)3N]+Cl?; [CH3(n-C8H17)3N]+HSO4?, [CH3(n-C8H17)3N]+H2PO4?; solvent: CHCl3 or toluene) were used to selectively and efficiently convert olefins to their corresponding epoxides at room temperature. With cyclooctene and using Arquad 2HT® as the phase-transfer agent, there is a synergy when both phosphate and sulfate anions are present in the reaction medium compared with systems using

Yahdih Mahha; Laurent Salles; Jean-Yves Piquemal; Emmanuel Briot; Ahmed Atlamsani; Jean-Marie Brégeault

2007-01-01

390

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

391

The GA sulfur-iodine water-splitting process - A status report  

NASA Technical Reports Server (NTRS)

The development of a sulfur-iodine thermal water splitting cycle is described. The process features a 50% thermal efficiency, plus all liquid and gas handling. Basic chemical investigations comprised the development of multitemperature and multistage sulfuric acid boost reactors, defining the phase behavior of the HI/I2/H2O/H3PO4 mixtures, and development of a decomposition process for hydrogen iodide in the liquid phase. Initial process engineering studies have led to a 47% efficiency, improvements of 2% projected, followed by coupling high-temperature solar concentrators to the splitting processes to reduce power requirements. Conceptual flowsheets developed from bench models are provided; materials investigations have concentrated on candidates which can withstand corrosive mixtures at temperatures up to 400 deg K, with Hastelloy C-276 exhibiting the best properties for containment and heat exchange to I2.

Besenbruch, G. E.; Chiger, H. D.; Mccorkle, K. H.; Norman, J. H.; Rode, J. S.; Schuster, J. R.; Trester, P. W.

1981-01-01

392

: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

393

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

394

CO2 Adsorption on Activated Carbon Honeycomb-Monoliths: A Comparison of Langmuir and T?th 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-Pirajan, Juan C.

2012-01-01

395

Low temperature wet etching to reveal sub-surface damage in sapphire substrates  

NASA Astrophysics Data System (ADS)

Low temperature wet etching using various etchants was investigated to reveal sub-surface damage in sapphire wafer induced during lapping. Surface scratches during wafer preparation is conveniently observed using optical or atomic force microscopy whereas sub-surface damage to crystal requires techniques such as X-ray diffraction, Raman spectroscopy etc. In this study, sub-surface damage in sapphire was revealed as shallow scratches by etching in H2SO4 at temperatures ˜125 °C and 3:1 H2SO4-H3PO4 at temperatures ˜75 °C. These etching conditions showed no measurable etch rate of sapphire and also did not affect the pristine sapphire surface. The heavily damaged and sub-surface damaged layer was determined to be 1.6 ± 0.1 and 2.2 ± 0.1 ?m deep by repeated chemical mechanical polishing and etching of sapphire wafer lapped with 1 ?m diamond abrasive.

Kumar, Purushottam; Lee, Jinhyung; Lee, Gwangwon; Rao, Suhas; Singh, Deepika; Singh, Rajiv K.

2013-05-01

396

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

397

Three-dimensional structuring of sapphire by sequential He+ ion-beam implantation and wet chemical etching  

NASA Astrophysics Data System (ADS)

We present a method for the selective two- and three-dimensional patterning of sapphire using light ion-beam implantation to generate severe lattice damage to depths exceeding 1 ?m and subsequent selective wet chemical etching of the damaged regions by hot H3PO4. C-cut sapphire crystals were implanted through contact masks using ion fluences of 1×1016 to 5×1017 He+/cm2 and energies up to 400 keV. The etching process is characterized by a high selectivity and a rate of approximately 19 nm/min. Whereas an implantation that produces a continuously damaged pathway results in complete etching from the surface, sole in-depth implantation using only high-energy ions leads to under-etching of the crystalline surface layer. By a combination of these processes we have fabricated three-dimensional structures such as channels and bridges in sapphire.

Crunteanu, A.; Jänchen, G.; Hoffmann, P.; Pollnau, M.; Buchal, C.; Petraru, A.; Eason, R. W.; Shepherd, D. P.

398

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.

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, H3PO4·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, C12H25(OCH2CH2)10OH, C12E10) molecules self-assemble into PANS-LLCMs and display high proton conductivity. The content of the PANS-LLCM can be as high 75% H3PO4·H2O and 25% 10-lauryl ether (C12H25(OCH2CH2)10OH, C12E10), 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, Omer

2014-10-28

400

Synthesis of MnPO 4·H 2O by refluxing process at atmospheric pressure  

NASA Astrophysics Data System (ADS)

Serrabrancaite (MnPO 4·H 2O) was synthesized by oxidizing Mn(H 2PO 4) 2 with NaClO solution using a refluxing process at atmospheric pressure, and a mixed solution of MnCl 2 and H 3PO 4 could substitute for Mn(H 2PO 4) 2 in the process. The products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Hureaulite was formed when single solution of Mn(H 2PO 4) 2 was refluxed for 12 h at 60 °C. Rodlike hureaulite was fabricated by refluxing reaction of 30 mmol Mn(H 2PO 4) 2 and 60 mmol NaClO solution with adding hydrochloric acid within 40 mmol. Granular hureaulite was formed by refluxing of 30 mmol MnCl 2 and 60 mmol NaClO solution with adding phosphoric acid within 30 mmol. For the two above-mentioned reaction systems, MnPO 4·H 2O was prepared by adding hydrochloric acid no less than 80 mmol and phosphoric acid no less than 60 mmol respectively. MnPO 4·H 2O yield increased with elevating reflux temperature, and increased firstly and then decreased with increasing additional amount of acid. The highest recovery yield of MnPO 4·H 2O reached 84.1% when Mn(H 2PO 4) 2 was performed as bivalent manganese source, and approached 74.0% when MnCl 2 and H 3PO 4 were used instead.

Qiu, Guohong; Gao, Zhiyun; Yin, Hui; Feng, Xionghan; Tan, Wenfeng; Liu, Fan

2010-05-01

401

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

PubMed

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

De, Bijay Krishna; Patel, J D

2010-01-01

402

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

403

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

NASA Astrophysics Data System (ADS)

Micro-supercapacitors are promising energy storage devices that can complement or even replace batteries in miniaturized portable electronics and microelectromechanical systems. Their main limitation, however, is the low volumetric energy density when compared with batteries. Here, we describe a hierarchically structured carbon microfibre made of an interconnected network of aligned single-walled carbon nanotubes with interposed nitrogen-doped reduced graphene oxide sheets. The nanomaterials form mesoporous structures of large specific surface area (396 m2 g-1) and high electrical conductivity (102 S cm-1). We develop a scalable method to continuously produce the fibres using a silica capillary column functioning as a hydrothermal microreactor. The resultant fibres show a specific volumetric capacity as high as 305 F cm-3 in sulphuric acid (measured at 73.5 mA cm-3 in a three-electrode cell) or 300 F cm-3 in polyvinyl alcohol (PVA)/H3PO4 electrolyte (measured at 26.7 mA cm-3 in a two-electrode cell). A full micro-supercapacitor with PVA/H3PO4 gel electrolyte, free from binder, current collector and separator, has a volumetric energy density of ~6.3 mWh cm-3 (a value comparable to that of 4 V-500 µAh thin-film lithium batteries) while maintaining a power density more than two orders of magnitude higher than that of batteries, as well as a long cycle life. To demonstrate that our fibre-based, all-solid-state micro-supercapacitors can be easily integrated into miniaturized flexible devices, we use them to power an ultraviolet photodetector and a light-emitting diode.

Yu, Dingshan; Goh, Kunli; Wang, Hong; Wei, Li; Jiang, Wenchao; Zhang, Qiang; Dai, Liming; Chen, Yuan

2014-07-01

404

Influence of different acid and alkaline cleaning agents on the effects of irrigation of synthetic dairy factory effluent on soil quality, ryegrass growth and nutrient uptake.  

PubMed

The aim of this study was to examine the effects of replacement of phosphoric acid with nitric or acetic acid, and replacement of NaOH with KOH, as cleaning agents in dairy factories, on the effects that irrigation of dairy factory effluent (DFE) has on the soil-plant system. A 16-week greenhouse study was carried out in which the effects of addition of synthetic dairy factory effluent containing (a) milk residues alone or milk residues plus (b) H(3)PO(4)/NaOH, (c) H(3)PO(4)/HNO(3)/NaOH or (d) CH(3)COOH/KOH, on soil's chemical, physical and microbial properties and perennial ryegrass growth and nutrient uptake were investigated. The cumulative effect of DFE addition was to increase exchangeable Na, K, Ca, Mg, exchangeable sodium percentage, microbial biomass C and N and basal respiration in the soil. Dry matter yields of ryegrass were increased by additions of DFE other than that containing CH(3)COOH. Plant uptake of P, Ca and Mg was in the same order as their inputs in DFE but for Na; inputs were an order of magnitude greater than plant uptake. Replacement of NaOH by KOH resulted in increased accumulation of exchangeable K. The effects of added NaOH and KOH on promoting breakdown of soil aggregates during wet sieving (and formation of a < 0.25 mm size class) were similar. Replacement of H(2)PO(4) by HNO(3) is a viable but CH(3)COOH appears to have detrimental effects on plant growth. Replacement of NaOH by KOH lowers the likelihood of phytotoxic effects of Na, but K and Na have similar effects on disaggregation. PMID:22707204

Liu, Y-Y; Haynes, R J

2013-01-01

405

Impact of struvite crystallization on nitrogen losses during composting of pig manure and cornstalk.  

PubMed

An absorbent mixture of magnesium hydroxide (Mg(OH)(2)) and phosphoric acid (H(3)PO(4)) was added to compost mixtures of pig manure with cornstalk in different molar ratios (T1, 1:1; T2, 1:2; T3, 1:3) in order to examine its effect on controlling ammonia losses during composting. Based on the principle of struvite precipitation, and with an unamended trial as control (CK), an in-vessel composting experiment was conducted in fermenters (60L with forced aeration) in which the absorbent mixture was added with proportions of 3.8%, 7.3% and 8.9% of dry weight for T1, T2 and T3, respectively. The results showed that the total nitrogen loss was reduced from 35% to 12%, 5% and 1% of initial N mass, respectively. In the final compost, the total nitrogen content in T1, T2 and T3 was improved by 10, 14, 12gkg(-1), and NH(4)(+)-N in T1, T2 and T3 was improved by 8, 9, and 10gkg(-1), respectively, compared with the unamended trial. The results of the germination index test showed that the maturity of treatment T2 was best among the four treatments in the final compost, followed by T1, CK and T3. The results of X-ray diffraction (XRD) confirmed the formation of magnesium ammonium phosphate hexahydrate (MgNH(4)PO(4).6H(2)O:MAP) in the T1, T2 and T3 compost. Based on these results, the adsorbent mixture of Mg(OH)(2)+H(3)PO(4) could control nitrogen loss effectively during composting via struvite crystallization. However, an excess of phosphoric acid (1:3) had a negative influence on composting properties. The pH value decreased which led to reduced microorganism activity, and which finally resulted in reduced biodegradation of the organic matter. PMID:20116232

Ren, Limei; Schuchardt, Frank; Shen, Yujun; Li, Guoxue; Li, Chunping

2010-05-01

406

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

407

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 ...

408

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 ...

409

CALCINATION OF CALCIUM HYDROXIDE SORBENT IN THE PRESENCE OF SO2 AND ITS EFFECT ON REACTIVITY  

EPA Science Inventory

The paper discusses the calcination of Ca(OH)2 sorbent in the presence of SO2 and its effect on reactivity. When Ca(0H)2 is calcined in an isothermal flow reactor with 300 ppm or less SO2, the structure of the sorbent is characterized by retention of higher pore volumes and surfa...

410

21 CFR 184.1205 - Calcium hydroxide.  

Code of Federal Regulations, 2010 CFR

...hydroxide. (a) Calcium hydroxide (Ca(OH)2 , CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of lime. (b) The ingredient meets the specifications of the Food Chemicals...

2010-04-01

411

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...

412

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...

413

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...

414

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 ...

415

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...

416

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...

417

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...

418

Comparative Evaluation of Endodontic Management of Teeth With Unformed Apices With Mineral Trioxide Aggregate and Calcium Hydroxide  

Microsoft Academic Search

Purpose: The purpose of this study was to compare mineral trioxide aggregate (MTA) and calcium hydroxide (Ca(OH)2) for their efficacies and time taken for formation of apical biological calcific barriers and resolution of periapical radiolucencies, if present at baseline, in teeth with unformed apices. Methods: Twenty nonvital permanent maxillary incisors with unformed apices, stratified according to the size of periapical

D. P. Pradhan; H. S. Chawla; K. Gauba; A. Goyal

419

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...

420

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...

421

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...

422

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

423

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...

424

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

425

Transport and spectroscopic studies of liquid and polymer electrolytes  

NASA Astrophysics Data System (ADS)

Liquid and polymer electrolytes are interesting and important materials to study as they are used in Li rechargeable batteries and other electrochemical devices. It is essential to investigate the fundamental properties of electrolytes such as ionic conductivity, diffusion, and ionic association to enhance battery performance in different battery markets. This dissertation mainly focuses on the temperature-dependent charge and mass transport processes and ionic association of different electrolyte systems. Impedance spectroscopy and pulsed field gradient nuclear magnetic resonance spectroscopy were used to measure the ionic conductivity and diffusion coefficients of ketone and acetate based liquid electrolytes. In this study, charge and mass transport in non-aqueous liquid electrolytes have been viewed from an entirely different perspective by introducing the compensated Arrhenius formalism. Here, the conductivity and diffusion coefficient are written as an Arrhenius-like expression with a temperature-dependent static dielectric constant dependence in the exponential prefactor. The compensated Arrhenius formalism reported in this dissertation very accurately describes temperature-dependent conductivity data for acetate and ketone-based electrolytes as well as temperature-dependent diffusion data of pure solvents. We found that calculated average activation energies of ketone-based electrolytes are close to each other for both conductivity and diffusion data (in the range 24-26 kJ/mol). Also, this study shows that average activation energies of acetate-based electrolytes are higher than those for the ketone systems (in the range 33-37 kJ/mol). Further, we observed higher dielectric constants and ionic conductivities for both dilute and concentrated ketone solutions with temperature. Vibrational spectroscopy (Infrared and Raman) was used to probe intermolecular interactions in both polymer and liquid electrolytes, particularly those which contain lithium trifluoromethanesulfonate, LiCF3SO3, abbreviated here as lithium triflate(LiTf). The molar absorption coefficients of nus(SO3), deltas(CF3), and deltas(SO3) vibrational modes of triflate anion in the LiTf-2-pentanone system were found to be 6708+/-89, 5182+/-62, and 189+/-2 kg mol-1 cm-1, respectively using Beer-Lambert law. Our results show that there is strong absorption by nu s(SO3) mode and weak absorption by deltas(CF 3) mode. Also, the absorptivity of each mode is independent of the ionic association with Li ions. This work allows for the direct quantitative comparison of calculated concentrations in different samples and different experimental conditions. In addition, this dissertation reports the temperature-dependent vibrational spectroscopic studies of pure poly(ethylene oxide) and LiTf-poly(ethylene oxide) complexes. A significant portion of this dissertation focuses on crystallographic studies of ketone-salt (LiTf:2-pentanone and NaTf:2-hexanone) and amine-acid (diethyleneamine: H3PO4, N,N'-dimethylethylenediamine:H 3PO4, and piperazine:H3PO4) systems. Here, sodium trifluoromethanesulfonate, NaCF3SO3 is abbreviated as NaTf. As model compounds, these systems provide valuable information about ion-ion interactions, which are helpful for understanding complex polymer systems. During this study, five crystal structures were solved using single X-ray diffractometry, and their vibrational modes were studied in the mid-infrared region. In the secondary amine/phosphoric acid systems, the nature of hydrogen-bonding network was examined.

Bopege, Dharshani Nimali

426

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

427

Production and engineering methods for Carb-Tek (trade name) batteries in fork lift trucks. Final report, July 1973December 1974. [Li--Al\\/KCl--LiCl\\/C with TeCl additive  

Microsoft Academic Search

The Carb-Tek battery employs a porous carbon cathode, a lithium-aluminum alloy anode, a eutectic mixture of potassium chloride and lithium chloride as the electrolyte, and a tellurium tetrachloride additive. The porous carbon cathode is an aggregation of active carbon particles which have been pressed together with a suitable binder. The Carb-Tek battery employs a solid plate anode which is an

Metcalfe

1974-01-01

428

The electrochemical measurements were conducted using a three-electrode cell at 25 C. A Pt wire and an Ag/AgCl (in saturated KCl) were used as the  

E-print Network

The electrochemical measurements were conducted using a three-electrode cell at 25 C. A Pt wire in Millipore water (18 MX cm). The working electrode was brushed with a cata- lyst ink as described previously.1±0.6 V versus NHE (NHE = nor- mal hydrogen electrode) to identify the properties of the Pt-based catalyst

Gao, Hongjun

429

??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

430

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

431

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

432

Pyrolysis of pine wood in a slowly heating fixed-bed reactor: Potassium carbonate versus calcium hydroxide as a catalyst  

Microsoft Academic Search

Catalytic pyrolysis of pine wood was carried out in a fixed-bed reactor heated slowly from room temperature to 700°C under a stream of purging argon to examine the effects of the physically mixed K2CO3 or Ca(OH)2 on the pyrolysis behaviors. K2CO3 demonstrated a stronger catalysis for decomposition of hemicellulose, cellulose and lignin constituents, leading to the reduced yield of liquid

Zhenya Wang; Fu Wang; Jianqin Cao; Jie Wang

2010-01-01

433

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

434

Comparative assessment of time-related bioactive glass and calcium hydroxide effects on mechanical properties of human root dentin.  

PubMed

Suspensions of micro- or nanoparticulate SiO(2)-Na(2)O-CaO-P(2)O(5) bioactive glasses could potentially be used as dressings in traumatized front teeth with open apices as an alternative to Ca(OH)(2). These materials have a disinfecting capacity similar to Ca(OH)(2), but bear the advantage of bioactivity. However, because bioactive glasses initially act as alkaline biocides just as Ca(OH)(2) does, they may also negatively affect mechanical dentin properties over time. This was assessed in the current study using standardized human root dentin bars. Specimens were immersed in 1:20 (wt vol(-1)) suspensions of nanometric bioactive glass 45S5 or calcium hydroxide for 1, 10, or 30 days. Control specimens were immersed in pure saline for 30 days (n = 20 per group). Subsequently, modulus of elasticity (E) and flexural strength (FS) of the specimens were determined. Results were compared between groups using one-way anova and Scheffé's post-hoc test. Ca(OH)(2) caused a significant (P < 0.001) 35% drop in mean flexural strength values compared to the control treatment after 10 days. No further change was observed between 10 days and 30 days. Bioactive glass caused a 20% drop in mean flexural strength as compared to the control after 10 days. However, this difference did not reach statistical significance (P > 0.05). No effects of either material on dentin modulus of elasticity values were observed. It was concluded that the calcium hydroxide suspension affected the dentin more than the bioactive glass counterpart; however, the effect was self-limiting and probably restricted to superficial dentin layers, as suggested by the mere decrease in flexural strength but not in modulus of elasticity values. PMID:19208025

Marending, Monika; Stark, Wendelin J; Brunner, Tobias J; Fischer, Jens; Zehnder, Matthias

2009-02-01

435

Transesterification of soybean oil catalyzed by fly ash and egg shell derived solid catalysts  

Microsoft Academic Search

A fly ash supported heterogeneous CaO catalyst has been developed using waste egg shell for transesterification of soybean oil to yield fuel grade biodiesel. The active metal precursor Ca(OH)2 of the catalyst has been economically derived from waste egg shell calcination and the mesoporous, high activity strong base catalyst has been prepared using wet-impregnation method. X-ray diffraction (XRD), scanning electron

R. Chakraborty; S. Bepari; A. Banerjee

2010-01-01