Sample records for kcl caoh2 h3po4

  1. CO electrooxidation study on Pt and Pt-Ru in H3PO4 using MEA with PBI-H3PO4 membrane

    NASA Astrophysics Data System (ADS)

    Modestov, A. D.; Tarasevich, M. R.; Leykin, A. Y.

    2011-03-01

    CO electrooxidation on Pt and Pt-Ru in H3PO4 was studied in the temperature range 120-180 °C using CO-N2-H2O gas mixtures of controlled composition. On Pt and Pt-Ru the voltammetry curves exhibited Tafel behavior in a wide potential range with a slope of 80-100 mV per decade. Replacement of Pt with Pt-Ru on the anode resulted mainly in a shift of CO electrooxidation voltammetry curves by approx. -0.3 V. Reaction order in respect to water vapor pressure was found close to unity with both electrocatalysts. Reaction order in respect to CO partial pressure was found negative, close to zero. Values of apparent activation energy of CO electrooxidation on these electrocatalysts were nearly equal, Ea app = 110 ± 15 kJ mol-1. The results were interpreted within the framework of Langmuir-Hinshelwood mechanism. An equation, which describes the observed features of CO electrooxidation on Pt and Pt-Ru, was suggested. Comparing results of the present study with results of earlier studies of CO tolerance of Pt and Pt-Ru electrocatalysts, it was concluded that CO electrooxidation can hardly play a significant role in CO tolerance of PEM FC with PBI-PA membranes.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

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

    Microsoft Academic Search

    M. Bendahou; M. Benabdellah; B. Hammouti

    2006-01-01

    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

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

    PubMed Central

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

    2014-01-01

    Rice husk, a surplus agricultural byproduct, was applied to the sorption of copper from aqueous solutions. Chemical modifications by treating rice husk with H3PO4 increased the sorption ability of rice husk for Cu(II). This work investigated the sorption characteristics for Cu(II) and examined the optimum conditions of the sorption processes. The elemental compositions of native rice husk and H3PO4-treated rice husk were determined by X-ray fluorescence (XRF) analysis. The scanning electron microscopic (SEM) analysis was carried out for structural and morphological characteristics of H3PO4-treated rice husk. The surface functional groups (i.e., carbonyl, carboxyl, and hydroxyl) of adsorbent were examined by Fourier Transform Infrared Technique (FT-IR) and contributed to the adsorption for Cu(II). Adsorption isotherm experiments were carried out at room temperature and the data obtained from batch studies fitted well with the Langmuir and Freundlich models with R2 of 0.999 and 0.9303, respectively. The maximum sorption amount was 17.0358?mg/g at a dosage of 2?g/L after 180?min. The results showed that optimum pH was attained at pH 4.0. The equilibrium data was well represented by the pseudo-second-order kinetics. The percentage removal for Cu(II) approached equilibrium at 180?min with 88.9% removal. PMID:24678507

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

    NASA Astrophysics Data System (ADS)

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

    2009-08-01

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

  6. Synergistic inhibition effect of 6-benzylaminopurine and iodide ion on the corrosion of cold rolled steel in H 3PO 4 solution

    Microsoft Academic Search

    Xianghong Li; Shuduan Deng; Hui Fu

    2011-01-01

    The synergistic inhibition effect of 6-benzylaminopurine (BAP) and iodide ion (I?) on the corrosion of cold rolled steel (CRS) in 1.0M H3PO4 solution was studied by weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The results show that BAP has a moderate inhibitive effect. However, incorporation of BAP with I? improves the inhibition performance significantly. The adsorption

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

    PubMed

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

    2008-08-15

    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

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

    PubMed

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

    2007-11-01

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

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

    PubMed Central

    Ahmad, F.; Sheha, E.

    2012-01-01

    A solid acid membranes based on poly (vinyl alcohol) (PVA), sodium bromide (NaBr) and phosphoric acid (H3PO4) were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM) studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10?3 S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications. PMID:25685413

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

    PubMed

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

    2014-01-30

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    Activated carbons with high mesoporosity and abundant oxygen-containing functional groups were prepared from water hyacinth using H3PO4 activation (WHAC) to eliminate Pb(II) in water. Characterizations of the WHAC were performed using Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The BET analysis showed that WHAC possesses a high mesoporosity (93.9%) with a BET surface area of 423.6 m2/g. The presence of oxygen-containing functional groups including hydroxyl, carbonyl, carboxyl and phosphate groups renders the WHAC a favorable adsorbent for Pb(II) with the maximum monolayer capacity (qm) 118.8 mg/g. The adsorption behavior follows pseudo-first order kinetic and Langmuir isotherm. The desorption study demonstrated that the WHAC could be readily regenerated using 0.1 M HCl (pH = 1.0). The desorbed WHAC could be reused at least six times without significant adsorption capacity reduction. The adsorption process was spontaneous and endothermic with ?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.

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

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald

    2005-01-01

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

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

    Microsoft Academic Search

    Marla E. Perez-Davis; Frank Difilipo

    1990-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Difilipo, Frank

    1990-01-01

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

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

    PubMed Central

    Mun, Ju-Hyun; Hwang, Hey-Zoo

    2014-01-01

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

  16. Odor Control in Evaporation Ponds Treating Olive Mill Wastewater Through the Use of Ca(OH)2

    Microsoft Academic Search

    E. Lagoudianaki; T. Manios; M. Geniatakis; N. Frantzeskaki; V. Manios

    2003-01-01

    Different amounts of Ca(OH)2 were added in 2 L beakers containing 1 L of olive mill wastewater (OMW). The mixture was stirred for 45 min and left to settle. Wastewater analysis was used in order to determine the effect of the different amounts of calcium hydroxide in the treating process, three days after the application. The Odor Detection Threshold was used for determining

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

    Microsoft Academic Search

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

    2003-01-01

    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

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

    NASA Technical Reports Server (NTRS)

    Meade, Charles; Jeanloz, Raymond

    1990-01-01

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

  19. Solubility of niobium in the system CaCO 3 Ca(OH) 2 -NaNbO 3 at 0.1 GPa pressure

    Microsoft Academic Search

    Roger H. Mitchell; Bruce A. Kjarsgaard

    2002-01-01

    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 x 3 as a primary liquidus phase until the melts contain greater than 60 wt% NaNbO3. The primary crystallization fields of calcite and

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

    PubMed

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

    2013-03-13

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

  1. Efficiencies of CaO\\/H 2O\\/Ca(OH) 2 chemical heat pump for heat storing and heating\\/cooling

    Microsoft Academic Search

    Hironao Ogura; Tetsuya Yamamoto; Hiroyuki Kage

    2003-01-01

    In order to save energy and decrease environmental impacts of thermal energy utilization systems, a CaO\\/H2O\\/Ca(OH)2 chemical heat pump (CHP) can be used for high-density heat storage and the cooling\\/heating functions. In this paper, the performance of the CHP for distinctive functions was examined in comparison with that of the other heat pumps based on the authors’ experimental and theoretical

  2. Synthesis and characterization of hydroxyapatite by microwave heating using CaSO4.2H2O and Ca(OH)2 as calcium source.

    PubMed

    Teoreanu, Ion; Preda, Maria; Melinescu, Alina

    2008-02-01

    In this paper, synthesis of hydroxyapatite (HAp) in the absence or presence of 1.05 wt% magnesium oxide, as sintering additive, by heating in a microwave oven was studied. For this purpose, CaSO(4).2H(2)O, Ca(OH)(2), Mg(OH)(2) and (NH(4))(2)HPO(4) were used as raw materials. The total chemical reactions for all the studied compositions were observed after a 3 h microwave treatment. In case of pure hydroxyapatite, a powder with needle-like grains results. In the presence of Mg(OH)(2), the (Mg, Ca(2)).O.(HPO(4))(2).H(2)O hydrated phosphate is formed besides hydroxyapatite. Pure hydroxyapatite, thermally treated at 1,200 degrees C, mostly transforms in beta-Ca(3)P(2)O(8). By adding MgO into the precursor mixture, hydroxyapatite was stabilised, and found in a much greater proportion at 1,200 degrees C. After the thermal treatment, the hydroxyapatite, analysed by electronic microscopy, shows a prismatic morphology originating in its initial state. PMID:17619995

  3. 134Cs uptake by four plant species and Cs-K relations in the soil-plant system as affected by Ca(OH)2 application to an acid soil.

    PubMed

    Massas, I; Skarlou, V; Haidouti, C; Giannakopoulou, F

    2010-03-01

    Three rates of Ca(OH)(2) were applied to an acid soil and the (134)Cs uptake by radish, cucumber, soybean and sunflower plants was studied. The (134)Cs concentration in all plant species was reduced from 1.6-fold in the sunflower seeds to 6-fold in the soybean vegetative parts at the higher Ca(OH)(2) rate. Potassium (K) concentration in plants was also reduced, but less effectively. The significantly decreased (134)Cs-K soil to plant distribution factors (D.F.) clearly suggest a stronger effect of soil liming on (134)Cs than on K plant uptake. This observation was discussed in terms of ionic interactions in the soil matrix and within the plants. The results also indicated that the increased Ca(2+) concentration in the exchange phase and in the soil solution along with the improved root activity, due to the soil liming, enhanced the immobilization of (134)Cs in the soil matrix and consequently lowered the (134)Cs availability for plant uptake. PMID:20044184

  4. Activated carbon from jackfruit peel waste by H 3PO 4 chemical activation: Pore structure and surface chemistry characterization

    Microsoft Academic Search

    Devarly Prahas; Y. Kartika; N. Indraswati; S. Ismadji

    2008-01-01

    The effects of activation temperature and impregnation ratio on the pore structure and surface chemistry of activated carbons derived from jackfruit peel with chemical activation method using phosphoric acid as activating agent were studied. Activated carbons with well-developed pore sizes were produced at activation temperatures of 450 and 550°C. The BET surface areas and total pore volumes of the carbons

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

    Microsoft Academic Search

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

    2010-01-01

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

  6. Supercapacitor Behavior with KCl Electrolyte

    Microsoft Academic Search

    Hee Y. Lee; J. B. Goodenough

    1999-01-01

    Amorphous MnO2·nH2O in a mild 2 M KCl aqueous electrolyte proves to be an excellent electrode for a faradaic electrochemical capacitor cycled between ?0.2 and +1.0 V versus SCE. In this potential range, it had ideal behavior with a specific capacitance ofca. 200 F\\/g, excellent cyclability at 2 mA\\/cm2over 100 cycles, and a short-circuit initial current density of 0.23 A\\/cm2with

  7. Absorption of colloidal silver in KCl

    Microsoft Academic Search

    W. Kleemann

    1968-01-01

    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

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

    PubMed

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

    2015-05-01

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

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

    Microsoft Academic Search

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

    2011-01-01

    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

  10. Laser characteristics of KCL:O2(-)

    NASA Astrophysics Data System (ADS)

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

    1983-10-01

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

  11. Gravity and General Relativity at KCL D C Robinson

    E-print Network

    Bushnell, Colin J.

    Gravity and General Relativity at KCL D C Robinson Mathematics Department King's College London Strand, London WC2R 2LS, UK. February 22, 2011 1 The study of gravity at KCL Research on gravity has been, an approach to New- tonian gravity similar to his field theory formulation of electromagnetism published

  12. Composition gradients in electrolyzed LiCl-KCl eutectic melts

    NASA Astrophysics Data System (ADS)

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

    1983-12-01

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

  13. Composition gradients in electrolyzed LiCl-KCL eutectic melts

    SciTech Connect

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

    1983-12-01

    Analysis of transport in a mixed electrolyte has previously predicted significant composition gradients in the LiCl-KCl electrolyte of high temperature Li/S batteries. Composition gradients in quenched electrolyzed LiCl-KCl eutectic contained in yttria felt are measured with high distance resolution by scanning electron microscopy with energy dispersive x-ray spectroscopy. The reported results include composition profiles of LiCl-KCl contained in porous Y/sub 2/O/sub 3/ and electrolyzed in three cells, two with solid Li-Al electrodes and one with a porous Li-Al anode.

  14. Composition gradients in electrolyzed LiCl-KCl melts

    SciTech Connect

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

    1983-01-01

    Analysis of transport in a mixed electrolyte has previously predicted significant composition gradients in the LiCl-KCl electrolyte of high-temperature Li/S batteries. Composition gradients in quenched electrolyzed LiCl-KCl eutectic are measured with high distance resolution by scanning electron microscopy with energy-dispersive x-ray spectroscopy. The reported results include compositions of LiCl-KCl contained in a porous Y/sub 2/O/sub 3/ matrix and electrolyzed between two solid Li/Al electrodes, and of the electrolyte in the pores of a powdered Li/Al electrode. The results provide quantitative measurements of the composition in the electrolyte, and demonstrate precipitation of LiCl in the porous anode.

  15. Molecular mechanism of KCl-induced relaxation of the esophagus.

    PubMed

    Yaktubay Dönda?, Naciye; Karata?, Yusuf; Kaya, Derya; Soylu, Neslihan; Singirik, Ergin; Baysal, Firuz

    2009-03-01

    KCl (40 mM) caused reproducible relaxations in frog esophagus. N(G)-nitro-L-arginine (L-NOARG; 1-100 microM), a steriospecific inhibitor of nitric oxide synthase (NOS), completely inhibited the relaxations induced by KCl but not those induced by vasoactive intestinal polypeptide (VIP) antagonist. The inhibitory effect of L-NOARG was prevented by L-arginine (L-ARG; 0.1-1 mM), the precursor of nitric oxide (NO) biosynthesis, but not by D-arginine (D-ARG; 0.1-0.5 mM), the enantiomer of L-arginine. L-ARG or D-ARG alone did not significantly modify the effect of KCl. The relaxations to KCl were significantly inhibited by omega conotoxin (omega-conotoxin; 0.1 microM), a selective blocker of N-type calcium channels. Propranolol (0.1-1 microM), a nonselective blocker of beta-adrenergic receptors, prazosine (0.01-0.1 microM), a selective blocker of alpha(1)-adrenergic receptors, phentolamine (0.1-1 microM), a nonselective blocker of adrenergic receptors, atropine, a selective blocker of muscarinic cholinergic receptors, and lidocaine (1-10 microM), a blocker of sodium channels, had no effect on KCl-evoked relaxations. Caffeine (500 microM), an intracellular calcium releasing agent, did not significantly modify the effect of KCl. In contrast, ruthenium red (100 microM), a selective blocker of ryanodine receptors (intracellular Ca(2+) channels), significantly inhibited these relaxations. Similarly, potassium channel blockers such as 4-aminopyridine (4-AP; 100 microM) and tetraethylammonium (TEA; 100 microM) caused a significant inhibition on relaxations to KCl. In addition, ouabain (100 microM), a specific blocker of Na(+)-K(+)-ATPase, also caused a significant inhibition on these relaxations. The results suggest that NO, Na(+)-K(+)-ATPase and potassium channels may have a role on relaxations induced by 40 mM KCl in the frog esophagus. PMID:19171133

  16. Study of an F center in molten KCl

    SciTech Connect

    Parrinello, M.; Rahman, A.

    1983-05-01

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

  17. VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA

    E-print Network

    Rudnyi, Evgenii B.

    1 VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA Rudnyi E in the vapors above alkali halides at high temperature introduces special problems in the assessment of thermodynamic properties of the vapor and the vaporization process, coupling pressure measurements

  18. Molecular dynamics simulations of the melting of KCl nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  19. Effects of KCl substitution on textural properties of Queso Fresco

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Partial substitution of KCl for NaCl has been attempted in some common cheese varieties because of restrictions on sodium in the diets of some consumers. The changes in texture of Queso Fresco, a popular Hispanic cheese, were monitored during refrigerated storage after replacing some of the NaCl wi...

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

    E-print Network

    Applebaum, David

    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

  1. Structure of CO2 monolayer on KCl(1 0 0)

    NASA Astrophysics Data System (ADS)

    Wu, Taiquan; Cao, Dan; Wang, Xinyan; Jiao, Zhiwei; Jiang, Zhouting; Chen, Miaogen; Luo, Honglei; Zhu, Ping

    2015-06-01

    The first-principle technique has been employed to determine the structure of carbon dioxide (CO2) dimers, molecular chains, monolayers and the CO2/KCl(1 0 0) system. Their potential structures have been proposed. CASTEP calculation shows that CO2 molecular chains and monolayers based on two stable dimers by the electric interaction are all self-assembly system. At the coverage of 1.00 ML, two stable structures have been proposed when CO2 monolayer on the KCl(1 0 0) surface. The best one is the monolayer adsorbed on the surface with the C atom in the bridge site, the angle ? between the molecular bond and the surface is 24°. The better one is the monolayer horizontally adsorbed on the surface with the C atom in the top-Cl site. The structural parameters in the adsorption system are similar to those in the monolayer.

  2. Aggregate centres of Ag - ions in KCl : Na crystals

    NASA Astrophysics Data System (ADS)

    Tsuboi, T.; Zota, S.; Topa, V.

    2001-01-01

    Not only (Ag -) 2 and Ag -(Na +) centres but also various Ag --Na + aggregate centres have been produced in Ag +-, Na +- and Ca 2+-codoped KCl crystals by unusual electrolytic colouration such as colouration at a relatively low temperature of 280°C and a high electric field of 5000 V/cm. Absorption and magnetic circular dichroism spectra due to these centres have been investigated.

  3. Optical absorption of Ag - centres in KCl: . line shape calculation

    NASA Astrophysics Data System (ADS)

    Zota, Sorina; Enculescu, Monica

    2000-02-01

    The line shapes of the absorption spectra of KCl : Ag - are calculated at several temperatures in the range 80-300 K and are compared with the experimental results. The complete 12×12 Hamiltonian matrix of the system, which includes the linear electron-lattice interaction, was diagonalized directly and the integration has been performed by the Gaussian quadrature method. The results explain most of the characteristic features experimentally observed.

  4. 3-Mercaptopropyltrimethoxysilane as a Cu corrosion inhibitor in KCl solution

    Microsoft Academic Search

    R. Tremont; H. De Jesús-Cardona; J. García-Orozco; R. J. Castro; C. R. Cabrera

    2000-01-01

    3-mercaptopropyltrimethoxysilane (MPS) has been used as a copper corrosion inhibitor in 0.100 mol L-1 KCl solution. The inhibition was studied as a function of the MPS pretreatment concentration in ethanol. The MPS concentration used was between 1.0 × 10-8 mol L-1 and 1.0 × 10-1 mol L-1. A freshly-cleaned Cu electrode was inserted in an ethanolic solution of MPS for

  5. Mechanisms of chloride influx during KCl-induced swelling in the chicken retina

    Microsoft Academic Search

    R. Lezama; B. Toscano; H. Pasantes-Morales

    2005-01-01

    An increase in extracellular KCl ([KCl]o) occurs under various pathological conditions in the retina, leading to retinal swelling and possible neuronal damage. The mechanisms of this KClo-induced retinal swelling were investigated in the present study, with emphasis on the Cl- transport mechanisms. Increasing [KCl]o (from 5 to 70 mM) led to concentration-dependent swelling in chicken retinas. The curve relating the degree

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

    PubMed Central

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

    2010-01-01

    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

  7. 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

    L. Y. Aranovich; R. C. Newton

    1997-01-01

    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,

  8. KCL 2006 A J H Simons, University of Sheffield, 2006 for Exetended and Modified Objects

    E-print Network

    Simons, Anthony J. H.

    Conformity Testing KCL 2006 © A J H Simons, University of Sheffield, 2006 Testing for Exetended and Modified Objects Anthony J H Simons #12;Regression Testing Model Base object proven correct by basic test set Derived object refines Base object in some way Base Btest conforms proves KCL 2006 © A J H Simons

  9. Electrical conductivity of low-temperature NaCl-KCl-ZrCl4 melts

    NASA Astrophysics Data System (ADS)

    Salyulev, A. B.; Khokhlov, V. A.; Red'kin, A. A.

    2014-08-01

    The dependences of the electrical conductivity of NaCl-KCl-ZrCl4 molten mixtures with a molar ratio NaCl : KCl = 8 : 29 on the temperature (temperature range of 300-540°C) and the ZrCl4 concentration (54.3-75.2 mol %) have been measured for the first time using unique cells.

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

    SciTech Connect

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

    1997-02-09

    Electrodialysis was investigated for cost-effective recovery of salt from salt cake leach solutions. (Salt cake is a waste stream generated by the aluminum industry during treatment of aluminum drosses and scrap.) We used a pilot-scale electrodialysis stack of 5 membrane pairs, each with an effective area of 0.02 m{sup 2}. The diluate stream contained synthetic NaCl, KCl,mixtures of NaCl and KCl, and actual salt cake leach solutions (mainly NaCl and KCl, with small amounts of MgCl{sub 2}). We concentrated and precipitated NaCl and KCl salts from the concentrate steam when the initial diluate stream concentration was 21.5 to 28.8 wt% NaCl and KCl. We found that water transferring through the membranes was a significant factor in overall efficiency of salt recovery by electrodialysis.

  11. KCl potentiation of the virucidal effectiveness of free chlorine at pH 9.0.

    PubMed Central

    Berg, G; Sanjaghsaz, H; Wangwongwatana, S

    1990-01-01

    In studies at 5 degrees C and pH 9.0, poliovirus 1 was inactivated about 15 times more rapidly by free chlorine (FC) in purified water in the presence of 1,262 mg of KCl per liter (approximately 0.0169 M) than in the absence of KCl. In the presence of 526 mg of KCl per liter, the virus was inactivated about seven times more rapidly by FC than in the absence of KCl. At a level of 21 mg/liter, KCl did not significantly potentiate the virucidal activity of FC in purified water. Although poliovirus 1 was inactivated almost three times more rapidly by FC in borate-buffered purified water than in purified water, the presence of the buffer did not alter the extent of potentiation by KCl. Most of FC exists as OCl- at pH 9.0. Tap water has been shown to markedly potentiate the polivirucidal effectiveness of FC at pH 9.0. For the same degree of virucidal potentiation of FC at this pH, a considerably greater quantity of KCl was required in purified water than the total salt content that appeared to be present in the tap water. PMID:2166468

  12. The clinical significance of K-Cl cotransport activity in red cells of patients with HbSC disease.

    PubMed

    Rees, David C; Thein, Swee Lay; Osei, Anna; Drasar, Emma; Tewari, Sanjay; Hannemann, Anke; Gibson, John S

    2015-05-01

    HbSC disease is the second commonest form of sickle cell disease, with poorly understood pathophysiology and few treatments. We studied the role of K-Cl cotransport activity in determining clinical and laboratory features, and investigated its potential role as a biomarker. Samples were collected from 110 patients with HbSC disease and 41 with sickle cell anemia (HbSS). K-Cl cotransport activity was measured in the oxygenated (K-Cl cotransport100) and deoxygenated (K-Cl cotransport0) states, using radioactive tracer studies. K-Cl cotransport activity was high in HbSC and decreased significantly on deoxygenation. K-Cl cotransport activity correlated significantly and positively with the formation of sickle cells. On multiple regression analysis, K-Cl cotransport increased significantly and independently with increasing reticulocyte count and age. K-Cl cotransport activity was increased in patients who attended hospital with acute pain in 2011 compared to those who did not (K-Cl cotransport100: mean 3.87 versus 3.20, P=0.009, independent samples T-test; K-Cl cotransport0: mean 0.96 versus 0.68, P=0.037). On logistic regression only K-Cl cotransport was associated with hospital attendance. Increased K-Cl cotransport activity was associated with the presence of retinopathy, but this effect was confounded by age. This study links variability in a fundamental aspect of cellular pathology with a clinical outcome, suggesting that K-Cl cotransport is central to the pathology of HbSC disease. Increased K-Cl cotransport activity is associated with increasing age, which may be of pathophysiological significance. Effective inhibition of K-Cl cotransport activity is likely to be of therapeutic benefit. PMID:25749827

  13. H2O activity in concentrated KCl and KCl-NaCl solutions at high temperatures and pressures measured by the brucite-periclase equilibrium

    NASA Astrophysics Data System (ADS)

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

    H2O activities in supercritical fluids in the system KCl-H2O-(MgO) were measured at pressures of 1, 2, 4, 7, 10 and 15 kbar by numerous reversals of vapor compositions in equilibrium with brucite and periclase. Measurements spanned the range 550-900°C. A change of state of solute KCl occurs as pressures increase above 2kbar, by which H2O activity becomes very low and, at pressures of 4kbar and above, nearly coincident with the square of the mole fraction (xH2O). The effect undoubtedly results primarily from ionic dissociation as H2O density (?H2O) approaches 1gm/cm3, and is more pronounced than in the NaCl-H2O system at the same P-T-X conditions. Six values of solute KCl activity were yielded by terminal points of the isobaric brucite-periclase T-xH2O curves where sylvite saturation occurs. The H2O mole fraction of the isobaric invariant assemblage brucite-periclase-sylvite-fluid is near 0.52 at all pressures, and the corresponding temperatures span only 100°C between 1 and 15kbar. This remarkable convergence of the isobaric equilibrium curves reflects the great influence of pressure on lowering of both KCl and H2O activities. The H2O and KCl activities can be expressed by the formulas: aH2O=?H2O[xH2O+(1+(1+?)xKCl)], and aKCL=?KCl[(1+?)xKCl/(xH2O+(1+?)xKCl)](1+?), where ? is a degree of dissociation parameter which increases from zero at the lowest pressures to near one at high pressures and the ?'s are activity coefficients based on an empirical regular solution parameter W: ln ?i=(1-xi)2W. Least squares fitting of our H2O and KCl activity data evaluates the parameters: ?=exp(4.166 -2.709/?H2O) - 212.1P/T, and W=(-589.6-23.10P) /T, with ?H2O in gm/cm3, P in kbar and T in K. The standard deviation from the measured activities is only +/-0.014. The equations define isobaric liquidus curves, which are in perfect agreement with previous DTA liquidus measurements at 0.5-2kbar, but which depart progressively from their extrapolation to higher pressures because of the pressure-induced dissociation effect. The great similarity of the NaCl-H2O and KCl-H2O systems suggests that H2O activities in the ternary NaCl-KCl-H2O system can be described with reasonable accuracy by assuming proportionality between the binary systems. This assumption was verified by a few reconnaissance measurements at 10kbar of the brucite-periclase equilibrium with a Na/(Na+K) ratio of 0.5 and of the saturation temperature for Na/(Na+K) of 0.35 and 0.50. At that pressure the brucite-periclase curves reach a lowest xH2O of 0.45 and a temperature of 587°C before salt saturation occurs, values considerably lower than in either binary. This double-salt eutectic effect may have a significant application to natural polyionic hypersaline solutions in the deep crust and upper mantle in that higher solute concentrations and very low H2O activities may be realized in complex solutions before salt saturation occurs. Concentrated salt solutions seem, from this standpoint, and also because of high mechanical mobility and alkali-exchanging potential, feasible as metasomatic fluids for a variety of deep-crust and upper mantle processes.

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

    NASA Astrophysics Data System (ADS)

    Stoch, J.; Ladecka, M.

    1988-05-01

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

  15. Thermite and Fe/KClO4: Some thermodynamic calculations

    NASA Astrophysics Data System (ADS)

    Woods, C. M.

    Heats of reaction were calculated for thermite materials consisting of various mixtures of Al, Al/Si, Fe2O3, and Ni. The primary reaction taking place in these thermites was the reduction of iron oxide by aluminum to form metallic iron and aluminum oxide. It was demonstrated that by taking into account all of the favored secondary reactions, the excess thermal output could be accounted for. Adiabatic flame temperatures were calculated. Average heat capacities were calculated for the temperature ranges from ambient to the AFT. Heat capacity calculations were also made in an attempt to understand the relationship between pole temperature and calorific output of various thermite and Fe/KClO4 components. Adiabatic flame temperatures were calculated using, as a closed system, the thermite material and its container. An empirical heat loss was subtracted from the available enthalpy of reaction. The remainder of the available heat was then used to calculate the system reduced adiabatic flame temperature which was termed the pole temperature projection. The results of these calculations were quite good when compared to actual measured values. Necessary heat losses were then calculated in the same fashion to fit the experimentally determined pole temperatures to a reduced AFT.

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

    USGS Publications Warehouse

    Potter, Robert W., II; Clynne, Michael A.

    1980-01-01

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

  17. Distribution behavior of plutonium and americium in LiCl–KCl eutectic\\/liquid cadmium systems

    Microsoft Academic Search

    Y Sakamura; O Shirai; T Iwai; Y Suzuki

    2001-01-01

    The thermodynamics of plutonium and americium in LiCl–KCl eutectic\\/liquid cadmium systems was studied with interest in the oxidation state of americium in the salt phase. The standard potential of plutonium vs. the Ag\\/AgCl (1 wt% AgCl) electrode, E0Pu\\/Pu(III), in the LiCl–KCl eutectic was measured in the temperature range of 400–500°C and given by the equation with a standard deviation, ?=0.0009

  18. Thin-Film Phase of Pentacene Film Formed on KCl by Vacuum Deposition

    NASA Astrophysics Data System (ADS)

    Kiyomura, Tsutomu; Nemoto, Takashi; Ogawa, Tetsuya; Minari, Takeo; Yoshida, Kaname; Kurata, Hiroki; Isoda, Seiji

    2006-01-01

    On KCl substrates, vacuum-deposited pentacene films are found to exhibit the so-called thin-film phase with 1.54 nm d-spacing perpendicular to the substrates when the film thickness is smaller than 30 nm. The films have in-plane unit cell sizes of a=0.59 nm, b=0.75 nm and ?=90°, which are almost the same as the values reported previously for the thin-film phase on SiO2/Si. The pentacene films formed on KCl show good epitaxy being composed of monomolecular layers with an approximately 1.5 nm step height. These films are oriented in the two epitaxial angles of 0 and 32° with respect to the a-axis of KCl. From the point-on-line epitaxy, a very small misfit value is found for the combination of the KCl(020) substrate and the thin-film phase (120) so that the a- or b-axes of the thin-film phase should orient making an angle of 32° from the a-axis of KCl, which explains exactly the observed 32° orientation. However, the 0° orientation can be explained not from the point-on-line epitaxy, but is suspected to be due to the nucleation controlled at surface steps along the a-axis of KCl.

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

    PubMed Central

    Antrobus, Shane P.; Lytle, Christian

    2012-01-01

    Using antibodies prepared against a unique region (exon 22–24) of rat K+-Cl? cotransporter-2 (KCC2), we confirmed that the ?140-kDa KCC2 protein is exclusively expressed in rat brain, but in chicken, we observed strong reactivity not only with the ?140-kDa KCC2 protein in brain but also a slightly larger ?145-kDa protein in heart. In silico analysis showed that while exon 22 of KCC2 is unique to this isoform in therian mammals, it is retained in KCC2's closest paralog, KCC4, of lower vertebrates, including chicken. To eliminate potential cross-reactivity with chicken KCC4, the antibodies were preadsorbed with blocking peptides prepared over the only two regions showing significant sequence identity to chicken KCC4. This completely eliminated antibody recognition of exogenously expressed chicken KCC4 but not of the ?145-kDa protein in chicken heart, indicating that chicken heart expresses KCC2. Real-time PCR confirmed robust KCC2 transcript expression in both chicken brain and heart. Chicken heart expressed predominantly the longer KCC2a splice variant consistent with the larger ?145-kDa protein in chicken heart. Immunofluorescence microscopy revealed prominent plasma membrane KCC2 labeling in chicken ventricular cardiomyocytes. We hypothesize that KCC2 is an important Cl? extrusion pathway in avian cardiomyocytes that counters channel-mediated Cl? loading during high heart rates with ?-adrenergic stimulation. While KCC2 is absent from mammalian cardiomyocytes, understanding the role that the other KCC isoforms play in Cl? homeostasis of these cells represents a nascent area of research. PMID:23034386

  20. Activation of K-Cl cotransport by mild warming in guinea pig red cells.

    PubMed

    Willis, J S; Anderson, G L

    1998-06-01

    Unidirectional, ouabain-insensitive K+ influx rose steeply with warming at temperatures above 37 degreesC in guinea pig erythrocytes incubated in isotonic medium. The only component of ouabain-insensitive K+ influx to show the same steep rise was K-Cl cotransport (Q10 of 10 between 37 and 41 degrees C); Na-K-Cl cotransport remained constant or declined and residual K+ influx in hypertonic medium with ouabain and bumetanide rose only gradually. Similar results were obtained for unidirectional K+ efflux. Thermal activation of K-Cl cotransport-mediated K+ influx was fully dependent on the presence of chloride in the medium; none occurred with nitrate replacing chloride. The increase of K+ influx through K-Cl cotransport from 37 to 41 degrees C was blocked by calyculin A, a phosphatase inhibitor. The Q10 of K-Cl cotransport fully activated by hydroxylamine and hypotonicity was about 2. The time course of K+ entry showed an immediate transition to a higher rate when cells were instantly warmed from 37 to 41 degrees C, but there was a 7-min time lag in returning to a lower rate when cells were cooled from 41 to 37 degrees C. These results indicate that the steepness of the response of K-Cl cotransport to mild warming is due to altered regulation of the transporter. Total unidirectional K+ influx was equal to total unidirectional K+ efflux at 37-45 degrees C, but K+ influx exceeded K+ efflux at 41 degrees C when K-Cl cotransport was inhibited by calyculin or prevented by hypertonic incubation. The net loss of K+ that results from the thermal activation of isosomotic K-Cl cotransport reported here would offset a tendency for cell swelling that could arise with warming through an imbalance of pump and leak for Na+ or for K+. PMID:9625776

  1. Evidence for inhibitory SH groups in the thiol activated K:Cl cotransporter of low K sheep red blood cells

    Microsoft Academic Search

    K. H. Ryu; P. K. Lauf

    1990-01-01

    The monofunctional thiol reagents N-ethylmaleimide (NEM) and methyl methanethiosulfonate (MMTS) stimulate ouabain resistant (OR) electroneutral K:Cl cotransport in LK sheep red blood cells at low, but not at high concentrations. Diamide (DM), on the other hand, only stimulates OR K:Cl flux (Lauf, P.K., J. Memb. Biol. 101: 179–188, 1988). The DM stimulated K:Cl cotransport was decreased toward the control value

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Ayyash, Mutamed M; Shah, Nagendra P

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

  5. Enhanced ionic conductivity and optical studies of plasticized (PEO-KCl) solid polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    Solid polymer electrolytes (SPEs) based on Polyethylene oxide (PEO) doped with potassium chloride (KCl) were prepared by the solution cast technique. The conductivity increases from 10-10 to 10-6 Scm-1 at 303K with dopant. Optical absorption study shows that the direct & indirect optical band gaps were found decreased from 5.45-4.46eV and 4.96-3.86eV respectively with increasing the KCl. The XRD patterns reveal increasing the amorphous with increasing the dopent. The obtained results suggest that, these polymer systems are suitable candidates for solid state battery, electro chromic devices & optoelectronics display etc.

  6. Analysis of the concentration dependence of KCl:Ag optical absorption by random-walk method

    Microsoft Academic Search

    Sergey Berdnikov; Irina Bobkova

    2001-01-01

    The absorption spectra of KCl:Ag single crystals with varied concentration of Ag+ ions are analyzed by the multivariable random-walk method. It is shown that intracenter absorption and charge-transfer with formation of perturbed-impurity centers of different coordination are responsible for the absorption event within the spectral range 6.35–5.3 eV.

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

    PubMed

    Oren, Aharon

    2013-01-01

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

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

    Microsoft Academic Search

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

    2010-01-01

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

  9. Thermodynamics of saturated aqueous solutions including mixtures of NaCl, KCl, and CsCl

    Microsoft Academic Search

    M. Conceicao P. de Lima; Kenneth S. Pitzer

    1983-01-01

    The activity coefficients for saturated aqueous KCl, CsCl and mixtures of NaCl with each of these electrolytes are calculated from solution properties using the ion interaction model as well as from the solubility. The agreement between the two sets of results for both single and mixed electrolytes is, in general, good when it is considered that the saturated solution molatities

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

    PubMed

    Lauf, P K

    1988-01-01

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

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

    Microsoft Academic Search

    Paul Wald; Sini Pitkkänen; Lynne Boddy

    2004-01-01

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

  12. Temporal signal stability of KCl:Eu2+ storage phosphor dosimeters

    PubMed Central

    Xiao, Zhiyan; Hansel, Rachael; Chen, Haijian; Du, Dongsu; Yang, Deshan; Harold Li, H.

    2013-01-01

    Purpose: Current KCl:Eu2+ 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:Eu2+ 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:Eu2+ 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 Cl2? Vk centers served as hole-storage centers for both undoped and doped KCl where a hole was trapped by a chlorine molecular ion. Vk centers were stable at low temperature and became mobile at room temperature, probably causing the observed PSL fading with time. On the other hand, Vk center could be stabilized by Eu2+ activator or oxygen in the lattice, leading to the stable component in the PSL. A thermal process at elevated temperatures (60 °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:Eu2+ 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. PMID:23387744

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  14. Electrochemical study of uranium cations in LiCl-KCl melt using a rotating disk electrode

    SciTech Connect

    Bae, Sang-Eun; Kim, Dae-Hyun; Kim, Jong-Yoon; Park, Tae-Hong; Cho, Young Hwan; Yeon, Jei-Won; Song, Kyuseok [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute,989-111 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

    2013-07-01

    A rotating disk electrode (RDE) measurement technique was employed to investigate the electrochemical REDOX reactions of actinide (An) and lanthanide (Ln) ions in LiCl-KCl molten salt. By using RDE, it is possible to access more exact values of the diffusion coefficient, Tafel slope, and exchange current density. In this work, we constructed RDE setup and electrodes for RDE measurements in high temperature molten salt and measured the electrochemical parameters of the An and Ln ions. The RDE setup is composed of a Pine model MSRX rotator equipped with a rod type of W electrode. The active electrode area was confined to the planar part of the W rod by making meniscus at the LiCl-KCl melt surface.

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

    PubMed

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

    2002-01-01

    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

  16. Theoretical studies on the SH parameters and local distortion structure of KCl:Ag2+ crystal

    Microsoft Academic Search

    W. L. Li; X. M. Li; W. L. Feng; W. J. Yang; C. Y. Tao

    2011-01-01

    Complete diagonalization of the energy matrix and high order perturbation formulae of spin-Hamiltonian (SH) parameters possessing D4h symmetry for the 4d9 ion based on the crystal- and ligand-field theory in tetragonal symmetry are expressed and applied to the study of local distortion structure of the KCl:Ag2+ crystal. The calculated results agree well with experimental findings. Both complete diagonalization of energy

  17. Theoretical studies on the SH parameters and local distortion structure of KCl:Ag 2+ crystal

    Microsoft Academic Search

    W. L. Li; X. M. Li; W. L. Feng; W. J. Yang; C. Y. Tao

    2011-01-01

    Complete diagonalization of the energy matrix and high order perturbation formulae of spin-Hamiltonian (SH) parameters possessing D4h symmetry for the 4d9 ion based on the crystal- and ligand-field theory in tetragonal symmetry are expressed and applied to the study of local distortion structure of the KCl:Ag2+ crystal. The calculated results agree well with experimental findings. Both complete diagonalization of energy

  18. Characterization of Fe\\/KClO4 Heat Powders and Pellets

    Microsoft Academic Search

    Ronald A. Guidotti; Judy Odinek; Frederick W. Reinhardt

    2006-01-01

    Pellets of Fe\\/KClO4 mixtures are used as a heat source for thermally activated (“thermal”) batteries. They provide the energy necessary for melting the electrolyte and bringing the battery stack to operating temperature. The effects of morphology of the Fe and the heat-pellet density and composition on both the physical properties (flowability, pelletization, and pellet strength) and the pyrotechnic performance (burn

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

    SciTech Connect

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

    2005-04-01

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

  20. Ab initio investigation of surface phonons on the (001) surface of KCl

    NASA Astrophysics Data System (ADS)

    Tütüncü, H. M.; Srivastava, G. P.

    2015-07-01

    We present an ab initio investigation of localised and resonant phonons on the relaxed KCl(001) surface. Our calculated results are in good accordance with recent high-resolution helium atom scattering measurements. The energy locations and atomic displacement patterns corresponding to a few characteristic surface phonons, such as the Rayleigh, Love, Wallis and Lucas modes, have been identified, and compared and contrasted with their counterparts obtained from a previous shell model calculation.

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

    Microsoft Academic Search

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

    2000-01-01

    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

  2. ESR spectrum of ClO trapped in KClO4

    NASA Astrophysics Data System (ADS)

    Byberg, J. R.

    1985-11-01

    The ESR spectrum of a paramagnetic defect produced in solid KClO4 by x irradiation at 26 K is attributed to the radical ClO since the magnetic hyperfine tensor and the nuclear quadrupole tensor of the defect are both satisfactorily accounted for in terms of the hyperfine and quadrupole constants of gaseous ClO combined with a crystal-field representation of the influence of the solid matrix.

  3. The K+–Cl? cotransporter KCC2 promotes GABAergic excitation in the mature rat hippocampus

    PubMed Central

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

    2010-01-01

    GABAergic excitatory [K+]o transients can be readily evoked in the mature rat hippocampus by intense activation of GABAA receptors (GABAARs). Here we show that these [K+]o responses induced by high-frequency stimulation or GABAA agonist application are generated by the neuronal K+–Cl? cotransporter KCC2 and that the transporter-mediated KCl extrusion is critically dependent on the bicarbonate-driven accumulation of Cl? in pyramidal neurons. The mechanism underlying GABAergic [K+]o transients was studied in CA1 stratum pyramidale using intracellular sharp microelectrodes and extracellular ion-sensitive microelectrodes. The evoked [K+]o transients, as well as the associated afterdischarges, were strongly suppressed by 0.5–1 mm furosemide, a KCl cotransport inhibitor. Importantly, the GABAAR-mediated intrapyramidal accumulation of Cl?, as measured by monitoring the reversal potential of fused IPSPs, was unaffected by the drug. It was further confirmed that the reduction in the [K+]o transients was not due to effects of furosemide on the Na+-dependent K+-Cl? cotransporter NKCC1 or on intraneuronal carbonic anhydrase activity. Blocking potassium channels by Ba2+ enhanced [K+]o transients whereas pyramidal cell depolarizations were attenuated in further agreement with a lack of contribution by channel-mediated K+ efflux. The key role of the GABAAR channel-mediated anion fluxes in the generation of the [K+]o transients was examined in experiments where bicarbonate was replaced with formate. This anion substitution had no significant effect on the rate of Cl? accumulation, [K+]o response or afterdischarges. Our findings reveal a novel excitatory mode of action of KCC2 that can have substantial implications for the role of GABAergic transmission during ictal epileptiform activity. PMID:20211979

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

    Microsoft Academic Search

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

    2010-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    Potassium Chloride (KCl) doped poly(vinyl alcohol) (PVA)/sodium alginate (NaAlg) in 60:40 wt% polymer blend electrolytes were prepared by solution casting method. The complexation of KCl with host PVA/NaAlg blend is confirmed by FTIR and UV-Vis spectra. The XRD studies show that the crystallinity of the prepared blends increases with increase in doping. The dc conductivity increases with increase in dopant concentration. Temperature dependent dc conductivity shows an Arrhenius behavior. The dielectric properties show that both the dielectric constant and dielectric loss increases with increase in KCl doping concentration and decreases with frequency. The cole-cole plots show a decrease in bulk resistance, indicates the increase in ac conductivity, due to increase in charge carrier mobility. The doping of KCl enhances the mechanical properties of PVA/NaAlg, such as Young's modulus, tensile strength, stiffness.

  6. O - detected by ESR as a radiation-induced electron-excess defect in KClO3

    NASA Astrophysics Data System (ADS)

    Byberg, J. R.

    1981-09-01

    A family of ESR spectra from KClO3 crystals irradiated with x rays at 26 K are assigned to electron-excess defects consisting of O- ions trapped in different environments, which may be identified because the electron spin on O- polarizes the adjacent ions. In the primary configurations, O- is associated with ClO-2. Secondary configurations, in which O- is trapped between two ClO-3 ions, arise from a thermally activated substitution process of the Grotthuss type: leading to migration of the excess negative charge along the crystallographic axis a. The O- defects in KClO3 are structurally very similar to those observed earlier in irradiated KClO4. As in KClO4, O- reacts with O2 at ˜230 K to yield O-3.

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

    NASA Astrophysics Data System (ADS)

    Safonov, O.

    2012-04-01

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

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

    PubMed Central

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

    2014-01-01

    The effects of high cumulative radiation dose on the luminescence properties of KCl:Eu2+ are investigated. Pellet samples of KCl:Eu2+ were given doses of up to 200 kGy at the Louisiana State University Synchrotron facility. After synchrotron irradiation, samples were optically bleached and given a clinical dose of 2 Gy from a 6 MV medical linear accelerator. Optical properties were evaluated using photostimulated luminescence (PSL), photoluminescence (PL), and temperature-dependent PSL measurements. For a cumulated dose of up to 5–10 kGy, the PSL emission intensity increased by 15% compared to the PSL signal with no radiation history. For doses higher than 10 kGy, the PSL emission intensity retained at least 70% of the original intensity. Spatial correlation of the charge storage centers increased for doses up to 5 kGy and then decreased for higher cumulative doses. Emission band at 975 nm was attributed to transitions of Eu1+. PL spectra showed an intense peak centered at 420 nm for all cumulative doses. The results of this work show that KCl:Eu2+ storage phosphors are excellent reusable materials for radiation therapy dosimetry. PMID:24778460

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    PubMed

    Lü, Y J; Wei, B

    2006-10-14

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

  11. Incorporation of Lactobacillus casei in Iranian ultrafiltered Feta cheese made by partial replacement of NaCl with KCl.

    PubMed

    Karimi, R; Mortazavian, A M; Karami, M

    2012-08-01

    Probiotic Iranian ultrafiltered Feta cheese was produced from ultrafiltration of milk with a volumetric concentration factor of 4.5:1. The heat-treated retentates were inoculated with 10(7) cfu of Lactobacillus casei LAFTI L26/mL. A mesophilic-thermophilic mixed culture of Lactococcus lactis ssp. lactis, Lactococcus lactis ssp. cremoris, and Streptococcus thermophilus was also used. Three percent (wt/wt) salt with different ratios of NaCl:KCl (100% NaCl, 50% NaCl:50% KCl, 75% NaCl:25% KCl, and 25% NaCl:75% KCl) were used in cheese formulation. The viability of L. casei was determined in treatments during the ripening period (90d at 5°C) within 15-d intervals. The pH, titratable acidity, and redox potential changes were monitored throughout the mentioned period. The mean pH drop rate, mean acidity increase rate, and mean redox potential increase rate were calculated at the end of the storage period. Also, total nitrogen, water-soluble nitrogen, lactic acid, and acetic acid concentrations, and syneresis and sensory characteristics of the product were measured during the mentioned period every 30d. The maximum viability of L. casei was observed within d 15 to 30 of the ripening period in the treatment containing the lowest amount of sodium. Addition of KCl enhanced syneresis. Cheeses with NaCl alone and with only 25% replacement by KCl have the highest sensory acceptability. PMID:22818434

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

    NASA Astrophysics Data System (ADS)

    Bjerre, Nis; Byberg, J. R.

    1981-11-01

    The optical absorption of KClO3 crystals irradiated with x-rays at 26 K are assigned to paramagnetic defects by correlating the changes in the optical absorption and ESR spectrum observed during annealing and selective bleaching. The polarization of the absorption bands and structure of the defects derived earlier by ESR indicate that three transitions involve charge transfer within the electron-excess defects: [O-,ClO3-]?[O(lD),C1O32-] (˜255nm), [O-,ClO-2]?[O(1D),ClO2-2] (˜ 385 nm), and [O-,ClO2-]?[O2-,ClO2] (˜ 295 nm), whereas transitions at 560 and 360 nm are assigned to charge transfer between ClO3 and an adjacent ClO-3 and to ClO2, respectively. The optical absorption of KClO4 similarly contains a strong band at 252 nm assigned to charge transfer within the electron-excess defects: [O-,ClO-3]?[O(1D),ClO32-]. Bands at 660 and 345 nm are assigned to charge transfer between the hole defect (ClO4)-2 and adjacent ClO-4 and to an internal transition in the ClO2 component of the hole defect [ClO2,O2], respectively. Bands at 430 and 530 nm probably belong to defects with integral electron spin. The charge transfer model is consistent with the observed migration of ClO3 and (ClO4)-2 during bleaching. Moreover, the model allows interpretation of photochemical conversions of the configuration of O- defects in terms of ''substitution'' reactions of the type A ''selection rule'' observed in the conversions of [ClO3-,O-] defects in KClO4 suggests that the oxygen atom to become O- after the excitation may be determined during the excitation process by the symmetry of the initial configuration. The interpretation of the spectra of O- defects leads to estimates of the electron affinities of ClO-2 and ClO-3: 0.2 and -1.5 eV, respectively.

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

    SciTech Connect

    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

    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.

  14. Fabrication of polyethersulfone (PES) membranes with nano-porous surface using potassium perchlorate (KClO 4) as an additive in the casting solution

    Microsoft Academic Search

    Ahmad Rahimpour; Sayed Siavash Madaeni; Yaghoub Mansourpanah

    2010-01-01

    Polyethersulfone (PES) membranes with nano-porous surface were fabricated by addition of potassium perchlorate (KClO4) as an additive in the casting solution. The membranes were prepared from PES\\/polyvinylpyrrolidone (PVP)\\/KClO4\\/dimethylacetamide (DMAc) via phase inversion induced by immersion precipitation technique. Mixture of water and isopropyl alcohol (IPA) was used as coagulation medium. The viscosity of PES casting solution increased with addition of KClO4.

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

    NASA Astrophysics Data System (ADS)

    Anishchik, V. M.; Val'Ko, N. G.; Vo?na, V. V.; Vorontsov, A. S.

    2008-07-01

    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.

  16. Hyperon production in Ar + KCl collisions at 1.76A GeV

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

    We present transverse momentum spectra, rapidity distribution and multiplicity of ? -hyperons measured with the HADES spectrometer in the reaction Ar(1.76AGeV) + KCl . The yield of ?^{{-}}_{} is calculated from our previously reported ?^{{-}}_{}/( ? + ?^{{0}}_{}) ratio and compared to other strange particle multiplicities. Employing a strangeness balance equation the multiplicities of the yet unmeasured ?^{{±}}_{} -hyperons can be estimated. Finally a statistical hadronization model is used to fit the yields of ?-_{} , K+, K 0 s , K-, ? , ? and ?-_{} . 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 different particles.

  17. Deep Subthreshold ?- Production in Ar+KCl Reactions at 1.76AGeV

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

    We report first results on a deep subthreshold production of the doubly strange hyperon ?- in a heavy-ion reaction. At a beam energy of 1.76AGeV the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity ? sample was collected, allowing for the investigation of the decay channel ?-???-. The deduced ?-/(?+?0) production ratio of (5.6±1.2-1.7+1.8)×10-3 is significantly larger than available model predictions.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    PubMed

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

    2009-09-25

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

  20. Degeneracy of the limited series of solid solutions in the NaCl-KCl-NH4Cl-H2O system at 50°C

    NASA Astrophysics Data System (ADS)

    Elsukov, A. V.; Mazunin, S. A.

    2015-06-01

    The phase equilibria in the NaCl-KCl-NH4Cl-H2O system at 50°C were studied. Sodium chloride was shown to destroy the limited compositions of (K,NH4)Cl and (NH4,K)Cl solid solutions. As the NaCl content increased, the solid solutions of the limited series on the line of monovariant equilibria of (K,NH4)Cl and (NH4,K)Cl with saturated solutions degenerated and the triply saturated solution with the individual salt components NaCl, KCl, and NH4Cl was in nonvariant equilibrium.

  1. The effect of substituting NaCl with KCl on Nabulsi cheese: chemical composition, total viable count, and texture profile.

    PubMed

    Ayyash, M M; Shah, N P

    2011-06-01

    The effect of substituting NaCl with KCl on Nabulsi cheese characteristics was investigated. Nabulsi cheese was made and stored in 4 different brine solutions at 18%, including NaCl only (A; control); 3NaCl:1KCl (wt/wt; B); 1NaCl:1KCl (wt/wt; C); and 1NaCl:3KCl (wt/wt; D). Chemical composition, proteolysis, total viable count, and texture profile analysis were assessed at monthly intervals for 5 mo. No significant effect was found among experimental cheeses in terms of chemical composition or texture profile. Proteolytic activities were higher in cheeses kept in brine solutions that contained higher KCl (B, C, and D) compared with the control. At the end of the storage period, water-soluble nitrogen in Nabulsi cheeses stored in B, C, and D was higher than that in the control cheese (A). In addition, total viable count increased significantly after 1 mo of storage for all salt treatments. Hardness and gumminess generally decreased significantly during storage within the same salt treatment. PMID:21605743

  2. Phase relations in the system NaCl-KCl-H2O: IV. Differential thermal analysis of the sylvite liquidus in the KCl-H2O binary, the liquidus in the NaCl-KCl-H2O ternary, and the solidus in the NaCl-KCl binary to 2 kb pressure, and a summary of experimental data for thermodynamic-PTX analysis of solid-liquid equilibria at elevated P-T conditions

    USGS Publications Warehouse

    Chou, I.-Ming; Sterner, S.M.; Pitzer, Kenneth S.

    1992-01-01

    The sylvite liquidus in the binary system KCl-H2O and the liquidus in the ternary system NaCl-KCl-H2O were determined by using isobaric differential thermal analysis (DTA) cooling scans at pressures up to 2 kbars. Sylvite solubilities along the three-phase curve in the binary system KCl-H2O were obtained by the intersection of sylvite-liquidus isopleths with the three-phase curve in a P-T plot. These solubility data can be represented by the equation Wt.% KCl (??0.2) = 12.19 + 0.1557T - 5.4071 ?? 10-5 T2, where 400 ??? T ??? 770??C. These data are consistent with previous experimental observations. The solidus in the binary system NaCl-KCl was determined by using isobaric DTA heating scans at pressures up to 2 kbars. Using these liquidus and solidus data and other published information, a thermodynamic-PTX analysis of solid-liquid equilibria at high pressures and temperatures for the ternary system has been performed and is presented in an accompanying paper (Part V of this series). However, all experimental liquidus, solidus, and solvus data used in this analysis are summarized in this report (Part IV) and they are compared with the calculated values based on the analysis. ?? 1992.

  3. Surface Morphology and Microstructural Characterization of KCl Crystals Grown in Halite-Sylvite Brine Solutions by Electron Backscattered Diffraction Techniques

    NASA Astrophysics Data System (ADS)

    Podder, Jiban; Basu, Ritwik; Evitts, Richard William; Besant, Robert William

    2015-11-01

    In this paper, a study on the ternary NaCl-KCl-H2O system was carried out by an extractive metallurgy technique from mixed brine solutions of different compositions at room temperature (23°C). The surface morphology and microstructure were examined using a scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and an energy dispersive X-ray (EDX) spectroscopy. The presence of Na{ }+ was found to reduce the stability of the solutions and increase the crystallization induction period, interfacial energy, energy of formation of the nucleus and greatly reduce the nucleation rate of KCl crystal. The surface morphology of KCl crystals is significantly changed due to presence of 5 to 10% (w/w) of NaCl as impurities in the binary solutions and shows the formation of co-crystals of different crystallographic orientation of NaCl on the KCl surface. In addition X-ray diffraction studies performed on KCl crystals grown in halite-sylvite binary solutions reveals that these crystals are cubic in nature and its lattice constant is 6.2952 Å when the NaCl concentration is small.

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

    SciTech Connect

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

    1999-07-14

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

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

    SciTech Connect

    Chen, Ken Shuang

    2009-04-01

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

  6. Small-molecule screen identifies inhibitors of the neuronal K-Cl cotransporter KCC2

    PubMed Central

    Delpire, Eric; Days, Emily; Lewis, L. Michelle; Mi, Dehui; Kim, Kwangho; Lindsley, Craig W.; Weaver, C. David

    2009-01-01

    KCC2, a neuronal-specific K-Cl cotransporter, plays a major role in maintaining intracellular Cl? concentration in neurons below its electrochemical equilibrium potential, thus favoring robust GABA hyperpolarizing or inhibitory responses. The pharmacology of the K-Cl cotransporter is dominated by loop diuretics such as furosemide and bumetanide, molecules used in clinical medicine because they inhibit the loop of Henle Na-K-2Cl cotransporter with much higher affinity. To identify molecules that affect KCC2 activity, we developed a fluorescence-based assay suitable for high-throughput screening (HTS) and used the assay to screen a library of 234,000 small molecules. We identified a large number of molecules that either decrease or increase the activity of the cotransporter. Here, we report the characterization of a small number of inhibitors, some of which inhibit KCC2 activity in the submicomolar range without substantially affecting NKCC1 activity. Using medicinal chemistry, we synthesized a number of variants, tested their effect on KCC2 function, and provide an analysis of structure/activity relationships. We also used one of the compounds to demonstrate competitive inhibition in regard to external [K+] versus noncompetitive inhibition in respect to external [Cl?]. PMID:19279215

  7. Multicomponent diffusion in molten LiCl-KCl: dynamical correlations and divergent Maxwell-Stefan diffusivities.

    PubMed

    Chakraborty, Brahmananda; Wang, Jin; Eapen, Jacob

    2013-05-01

    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. PMID:23767545

  8. Chemical Crosslinking Studies with the Mouse Kcc1 K-Cl Cotransporter

    PubMed Central

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

    2009-01-01

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

  9. K-Cl transport systems in rabbit renal basolateral membrane vesicles

    SciTech Connect

    Eveloff, J.; Warnock, D.G.

    1987-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    USGS Publications Warehouse

    Chou, I.-Ming

    1982-01-01

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

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

    PubMed Central

    Silayeva, Liliya; Liang, Bo; Kaila, Kai; Moss, Stephen J.

    2015-01-01

    The K–Cl cotransporter KCC2 establishes the low intraneuronal Cl? levels required for the hyperpolarizing inhibitory postsynaptic potentials mediated by ionotropic g-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

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

    SciTech Connect

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

    2013-07-01

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

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

    PubMed Central

    Benisek, Artur; Dachs, Edgar

    2013-01-01

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

  15. [Investigations of transient time-dependent spectral multi-channel measurement for shocked KCl crystal].

    PubMed

    Cheng, Juan; He, Ying-hong; Zuo, Hao-yi; Ran, Rui-jiang; Xue, Kang; Yang, Jing-guo; Tan, Hua; Hu, Shao-lou; Wang, Xiao-song

    2004-12-01

    In this paper, the authors reported a new method for measuring transient time-dependent spectra using multi-fiber delay coupler and optical multi-channel analysis technique. The fiber delay coupler consists of five fibers with different lengths and its time-delay between two fibers is determined by the different fiber lengths. The light beams that came from the fiber coupler were coupled by a lens system into the slit of a spectrograph and formed a spectral pattern on the focus plane of the spectrometer. A two-dimensional CCD detector converted the optical pattern into an electrical pattern, and then the transient time-dependent spectra were obtained by a personal computer. The experimental setup was constructed, and the transient time-dependent spectra were measured for KCl crystal shocked by a high speed pill. The time resolution was 20 ns, and the spectral intensity resolution reached 1/18 bit. PMID:15828310

  16. Ab initio model potential embedded-cluster calculation of the geometric structure of Tl + monomer and dimer centers in KCl

    Microsoft Academic Search

    J. L. Pascual; Z. Barandiarán; L. Seijo

    2001-01-01

    When alkali halide crystals are doped with ns2 impurities such as Tl+, dimer centers as well as monomer centers are formed. In this paper, we present the results of ab initio model potential (AIMP) embedded cluster calculations of the geometric structure of the centers formed in Tl+-doped KCl. Using the AIMP method, which is able to bring into an ab

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

    E-print Network

    Berry, R. Stephen

    Range effects of the Coulombic forces on structures, thermodynamic properties and potential energy Available online 25 November 2011 Keywords: Clusters Interaction potentials Range of interactions Topography for (KCl)n systems, we study the effects of the range of the Coulombic interactions on the structures

  18. Evidence for inhibitory SH groups in the thiol activated K:Cl cotransporter of low K sheep red blood cells.

    PubMed

    Ryu, K H; Lauf, P K

    1990-12-20

    The monofunctional thiol reagents N-ethylmaleimide (NEM) and methyl methanethiosulfonate (MMTS) stimulate ouabain resistant (OR) electroneutral K:Cl cotransport in LK sheep red blood cells at low, but not at high concentrations. Diamide (DM), on the other hand, only stimulates OR K:Cl flux (Lauf, P.K., J. Memb. Biol. 101: 179-188, 1988). The DM stimulated K:Cl cotransport was decreased toward the control value prior to DM stimulation when NEM or MMTS were added, subsequently. The inhibitory effect was dependent on the compound's concentration and exposure time and, in the case of MMTS, was reversed upon addition of dithiothreitol (DTT). The inhibition was more prominent when NEM treatment was performed at pH 8.0 and disappeared at pH 6.0. In contrast the NEM stimulatory effect was most effective when the pH of NEM treatment was 6.0 (Bauer, J. & Lauf, P.K., J. Memb. Biol. 73: 257-261, 1983). The results suggest the existence of additional, however, inhibitory thiol groups in the already thiol-activated K:Cl cotransporter, with a different pKa value and a lower affinity for NEM or MMTS as compared to the stimulatory thiol groups. Like the activating thiols, the inhibitory sulfhydryls appeared to be inaccessible to non-penetrating thiol reagents and hence, must be located deeper within the red cell membrane. PMID:2287344

  19. Micro-structural study of the GeS2-In2S3-KCl glassy system by Raman scattering.

    PubMed

    Haizheng, Tao; Xiujian, Zhao; Wei, Tong; Shun, Mao

    2006-07-01

    Room temperature Raman spectra of samples on three serials within the GeS(2)-In(2)S(3)-KCl glassy system have been investigated systematically. According to XRD patterns and Raman spectra of several pseudo-binary systems, the Cl atoms, which was added into the GeS(2)-In(2)S(3) glasses through KCl, was considered to be leading to the breaking of In-In bonds among the S(3)In-InS(3) ethane-like units and the forming of InS(4-x)Cl(x), InS(6-x)Cl(x) mixed polyhedra. Considering the effect of K(+) ions upon mixed anion units (InS(4-x)Cl(x) and InS(6-x)Cl(x)) and the corresponding micro-structural model, the Raman spectral evolution of the GeS(2)-In(2)S(3)-KCl glasses can be elucidated successfully. The microstructure of the GeS(2)-In(2)S(3)-KCl glasses was considered to be that the potassium atoms, which exist in the form of chlorine atoms as its nearest neighbor, are homogeneously dispersed in the glassy net formed by the micro-structural units such as InS(4), InS(6), InS(4-x)Cl(x), InS(6-x)Cl(x), GeS(4) polyhedra and S(3)In(Ge)-In(Ge)S(3) ethane-like units. PMID:16458057

  20. A Study of Gamma-Ray Diffraction Caused by Thermal Diffuse Scattering in KCl Single Crystal Using the Mössbauer Effect

    NASA Astrophysics Data System (ADS)

    Kashiwase, Yasuji; Kainuma, Yoshiro; Minoura, Masayuki

    1982-03-01

    Dips of the inelastic intensity profiles in 200, 400 and 600 Bragg reflections from a KCl crystal were observed by means of Mössbauer diffraction using 14.4 keV ?-rays and a position sensitive detector. It is concluded that the dips are caused by the thermal diffuse scattering of ?-rays which is reflected secondarily by the net planes in the same crystal.

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

    PubMed

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

    2006-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

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

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

    SciTech Connect

    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

    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.

  4. Toxicity and carcinogenicity of acidogenic or alkalogenic diets in rats; effects of feeding NH(4)Cl, KHCO(3) or KCl.

    PubMed

    Lina, B A R; Kuijpers, M H M

    2004-01-01

    The effects of diet-induced acid-base disturbances were examined in 4-week, 13-week and 18-month toxicity studies, and in a 30-month carcinogenicity study. Rats were fed a natural ingredient diet (controls), supplemented with 2% or 4% KHCO(3) (base-forming diets), or with 1% or 2.1% NH(4)Cl (acid-forming diets). Additional controls were fed 3% KCl (neutral diet providing K(+) and Cl(-) in amounts equimolar to those in the 4% KHCO(3) diet and the 2.1% NH(4)Cl diet, respectively). NH(4)Cl induced the expected metabolic acidosis, as shown by decreased base excess in blood, decreased urinary pH and increased urinary net acid excretion. KHCO(3) induced the opposite effects. KCl did not affect the acid-base balance. Clinical condition and death rate were not affected. The feeding of high levels of each salt resulted in growth retardation and increased water intake and urinary volume. Plasma potassium and urinary potassium excretion were increased with KHCO(3) and KCl. Plasma chloride was increased with NH(4)Cl, but not with KCl. Urinary calcium and phosphate excretion were increased with NH(4)Cl, but there were no indications that bone minerals were involved (weight, calcium content and fat free solid of the femur were not affected). Standard haematological and clinical chemistry parameters were not affected. Kidney weights were increased with 2.1% NH(4)Cl. Hypertrophy of the adrenal zona glomerulosa occurred with KHCO(3), KCl and NH(4)Cl, due to chronic stimulation of the adrenal cortex by either K(+) or by NH(4)Cl-induced acidosis. An early onset (from week 13) of oncocytic tubules was noted in the kidneys of rats fed KHCO(3) and, after 30 months, the incidence of this lesion was much higher than the background incidence in ageing controls. No progression to oncocytomas was noted. KCl showed only slight effects on the early onset of oncocytic tubules (from 18 months). In contrast, the severity of nephrosis and the incidence of oncocytic tubules were decreased with 2.1% NH(4)Cl, suggesting a protective effect of acidosis. The feeding of KHCO(3) resulted in hyperplasia, papillomas and carcinomas of the urinary bladder. With KCl only a slight increase in proliferative urothelial lesions was noted. Apart from these (pre-)neoplastic lesions in the urinary bladder there were no treatment-related differences in tumour response among the groups. We concluded that most of the observed changes represent physiological adaptations to the feeding of acid- or base-forming salts. Remarkable effects noted with KHCO(3), and to a far lesser extent with KCl, consisted of renal oncocytic tubules and (pre-)neoplastic lesions of the urinary bladder epithelium. NH(4)Cl-induced chronic metabolic acidosis was not associated with dissolution of alkaline bone salts in rats. Finally, a protective effect of chronic acidosis on tumour development was not found. PMID:14630137

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Principal Hugoniot and K-shell X-ray absorption spectra of warm dense KCl are calculated using the first-principles molecular dynamics (FPMD) method. Evolution of electronic structures as well as the influence of the approximate description of ionization on pressure (caused by the underestimation of the energy gap between conduction bands and valence bands) in the first-principles method are illustrated by the calculation. It is shown that approximate description of ionization in FPMD has small influence on Hugoniot pressure due to mutual compensation of electronic kinetic pressure and virial pressure. The calculation of X-ray absorption spectra shows that the band gap of KCl persists after the pressure ionization of the 3p electrons of Cl and K taking place at lower energy, which provides a detailed understanding to the evolution of electronic structures of warm dense matter.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed

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

    2009-08-01

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

  9. ?-p femtoscopy in collisions of Ar+KCl at 1.76A GeV

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    Results on ?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 ? sample was collected, allowing for the investigation of ?p correlations at low relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the ?p emission source. The ?p source radius is found to be slightly smaller than the pp correlation radius for a similar collision system. The present ?p radius is significantly smaller than that found for Au+Au/Pb+Pb collisions in the AGS, SPS, and RHIC energy domains but larger than that observed for electroproduction from He. Taking into account all available data, we find the ?p source radius to increase almost linearly with the number of participants to the power of one-third.

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

    SciTech Connect

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

    1986-01-01

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

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

    SciTech Connect

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

    1997-03-01

    An existing method for potentiometric titrations of proteins was improved, tested and applied to titrations of the enzyme hen-egg-white lysozyme in aqueous solutions containing KCl at ionic strengths from 0.1 M to 2.0 M at 25 C. Information about the protein`s net charge dependence on pH and ionic strength were obtained and salt binding numbers for the system were calculated using a linkage concept. For the pH range 2.5--11.5, the net charge slightly but distinctly increases with increasing ionic strength between 0.1 M and 2.0 M. The differences are most distinct in the pH region below 5. Above pH 11.35, the net charge decreases with increasing ionic strength. Preliminary calculation of binding numbers from titration curves at 0.1 M and 1.0 M showed selective association of chloride anions and expulsion of potassium ions at low pH. Ion-binding numbers from this work will be used to evaluate thermodynamic properties and to correlate crystallization or precipitation phase-equilibrium data in terms of a model based on the integral-equation theory of fluids which is currently under development.

  12. Dielectron production in Ar + KCl collisions at 1.76A GeV

    SciTech Connect

    Agakishiev, G.; Belyaev, A.; Chernenko, S.; Fateev, O.; Zanevsky, Y. [Joint Institute of Nuclear Research, RU-141980 Dubna (Russian Federation); Balanda, A.; Dybczak, A.; Michalska, B.; Otwinowski, J.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M. [Smoluchowski Institute of Physics, Jagiellonian University of Cracow, PL-30-059 Krakow (Poland); Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J. A. [Departamento de Fisica de Particulas, Univ. de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Blanco, A.; Fonte, P.; Lopes, L. [LIP-Laboratorio de Instrumentacao e Fisica Experimental de Particulas, P-3004-516 Coimbra (Portugal)

    2011-07-15

    We present results on dielectron production in {sup 40}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{sup +}e{sup -} invariant masses, we find a strong enhancement of the pair yield over a reference spectrum from elementary nucleon-nucleon reactions, suggesting the onset of nontrivial 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.

  13. Mechanism, regulation and physiological significance of the loop diuretic-sensitive NaCl\\/KCl symport system in animal cells

    Microsoft Academic Search

    Milton H. Saier; David A. Boyden

    1984-01-01

    Investigations in numerous laboratories have characterized a salt transport system, present in many animal cell types, which catalyzes the transmembrane transport of NaCl and KCI in a tightly coupled process. The system is inhibited by loop diuretics such as furosemide and bumetanide. This transport system has been designated the loop diuretic-sensitive NaCl\\/KCl symporter. It has been implicated in transepithelial salt

  14. Preparation of Al-La Master Alloy by Thermite Reaction in NaF-NaCl-KCl Molten Salt

    NASA Astrophysics Data System (ADS)

    Jang, Poknam; Li, Hyonmo; Kim, Wenjae; Wang, Zhaowen; Liu, Fengguo

    2015-05-01

    A NaF-NaCl-KCl ternary system containing La2O3 was investigated for the preparation of Al-La master alloy by the thermite reaction method. The solubility of La2O3 in NaF-NaCl-KCl molten salt was determined by the method of isothermal solution saturation. Inductively coupled plasma-optical emission spectroscopy and x-ray diffraction (XRD) analyses were used to consider the content of La2O3 in molten salt and the supernatant composition of molten salt after dissolution of La2O3, respectively. The results showed that the content of NaF had a positive influence on the solubility of La2O3 in NaF-NaCl-KCl molten salts, and the solubility of La2O3 could reach 8.71 wt.% in molten salts of 50 wt.%NaF-50 wt.% (44 wt.%NaCl + 56 wt.%KCl). The XRD pattern of cooling molten salt indicated the formation of LaOF in molten salt, which was probably obtained by the reaction between NaF and La2O3. The kinetic study showed that the thermite reaction was in accord with a first-order reaction model. The main influence factors on La content in the Al-La master alloy product, including molten salt composition, amount of Al, concentration of La2O3, stirring, reduction time and temperature, were investigated by single-factor experimentation. The content of La in the Al-La master alloy could be reached to 10.1 wt.%.

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

    Microsoft Academic Search

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

    1985-01-01

    Properties of the NaCl\\/KCl cotransport system were investigated in isolated membranes by flux measurements and binding studies. Chloride competes with “furosemide-like loop diuretics” for its two binding sites at the cotransporter as evidenced by the decrease in piretanide sensitivity of sodium flux and inhibition of high affinity N-methylfurosemide binding by chloride in rectal gland plasma membranes. In the rectal gland

  16. KCl Depolarization Increases HIF-1 Transcriptional Activity via the Calcium-Independent Pathway in SGC7901 Gastric Cancer Cells

    Microsoft Academic Search

    Mei Lan; Yongquan Shi; Li Sun; Lili Liu; Xueyan Guo; Yuanyuan Lu; Jun Wang; Jie Liang; Daiming Fan

    2007-01-01

    Background: Hypoxia-inducible factor 1? (HIF-1?) has been reported to be expressed aberrantly in gastric cancer cells. Stability and transactivation of HIF-1 were associated with the change of intracellular calcium. We hypothesized that KCl depolarization may modulate HIF-1 activity in gastric cancer cells through calcium involvement. Methods: HIF-1? expression and its transcriptional activity were determined in SGC7901 gastric cancer cells treated

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

    Microsoft Academic Search

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

    2006-01-01

    SLC12A cation\\/Cl- cotransporters are mutated in human disease, are targets of diuretics, and are collectively involved in the regulation of cell volume, neuronal excitability, and blood pressure. This gene family has two major branches with different physiological functions and inverse regulation: K-Cl cotransporters (KCC1-KCC4) mediate cellular Cl- efflux, are inhibited by phosphorylation, and are activated by dephosphorylation; Na-(K)-Cl cotransporters (NCC

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

    SciTech Connect

    Li, J.C.M.

    1981-01-01

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

  19. Pressure induced structural phase transition in solid oxidizer KClO3: A first-principles study

    NASA Astrophysics Data System (ADS)

    Yedukondalu, N.; Ghule, Vikas D.; Vaitheeswaran, G.

    2013-05-01

    High pressure behavior of potassium chlorate (KClO3) has been investigated from 0 to 10 GPa by means of first principles density functional theory calculations. The calculated ground state parameters, transition pressure, and phonon frequencies using semiempirical dispersion correction scheme are in excellent agreement with experiment. It is found that KClO3 undergoes a pressure induced first order phase transition with an associated volume collapse of 6.4% from monoclinic (P21/m) ? rhombohedral (R3m) structure at 2.26 GPa, which is in good accord with experimental observation. However, the transition pressure was found to underestimate (0.11 GPa) and overestimate (3.57 GPa) using local density approximation and generalized gradient approximation functionals, respectively. Mechanical stability of both the phases is explained from the calculated single crystal elastic constants. In addition, the zone center phonon frequencies have been calculated using density functional perturbation theory at ambient as well as at high pressure and the lattice modes are found to soften under pressure between 0.6 and 1.2 GPa. The present study reveals that the observed structural phase transition leads to changes in the decomposition mechanism of KClO3 which corroborates with the experimental results.

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

    NASA Astrophysics Data System (ADS)

    Bakker, Ronald J.

    2012-05-01

    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.

  1. An optimal method for phosphorylation of rare earth chlorides in LiCl-KCl eutectic based waste salt

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    A study on an optimal method for the phosphorylation of rare earth chlorides in LiCl-KCl eutectic waste salt generated the pyrochemical process of spent nuclear fuel was performed. A reactor with a pitched four blade impeller was designed to create a homogeneous mixing zone in LiCl-KCl eutectic salt. A phosphorylation test of NdCl3 in the salt was carried out by changing the operation conditions (operation temperature, stirring rate, agent injection amount). Based on the results of the test, a proper operation condition (450 °C, 300 rpm, 1 eq. of phosphorylation agent) for over a 0.99 conversion ratio of NdCl3 to NdPO4 was determined. Under this condition, multi-component rare earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Y) chlorides were effectively converted into phosphate forms. It was confirmed that the existing regeneration process of LiCl-KCl eutectic waste salt can be greatly improved and simplified through these phosphorylation test results.

  2. Current view on the functional regulation of the neuronal K+-Cl? cotransporter KCC2

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2015-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  5. Enhancing K-Cl co-transport restores normal spinothalamic sensory coding in a neuropathic pain model.

    PubMed

    Lavertu, Guillaume; Côté, Sylvain L; De Koninck, Yves

    2014-03-01

    Neuropathic pain is a widespread and highly debilitating condition commonly resulting from injury to the nervous system, one main sequela of which is tactile allodynia, a pain induced by innocuous mechanical stimulation of the skin. Yet, the cellular mechanisms and neuronal substrates underlying this pathology have remained elusive. We studied this by quantifying and manipulating behavioural and neuronal nociceptive thresholds in normal and pathological pain conditions. We found that, in both control rats and those with pain hypersensitivity induced by nerve injury, the nociceptive paw withdrawal threshold matches the response threshold of nociceptive-specific deep spinothalamic tract neurons. In contrast, wide dynamic range or multimodal spinothalamic tract neurons showed no such correlation nor any change in properties after nerve injury. Disrupting Cl(-) homeostasis by blocking K(+)-Cl(-) co-transporter 2 replicated the decrease in threshold of nociceptive-specific spinothalamic tract neurons without affecting wide dynamic range spinothalamic tract cells. Accordingly, only combined blockade of both GABAA- and glycine-gated Cl(-) channels replicated the effects of nerve injury or K(+)-Cl(-) co-transporter 2 blockade to their full extent. Conversely, rescuing K(+)-Cl(-) co-transporter 2 function restored the threshold of nociceptive-specific spinothalamic tract neurons to normal values in animals with nerve injury. Thus, we unveil a tight association between tactile allodynia and abnormal sensory coding within the normally nociceptive-specific spinothalamic tract. Thus allodynia appears to result from a switch in modality specificity within normally nociceptive-specific spinal relay neurons rather than a change in gain within a multimodal ascending tract. Our findings identify a neuronal substrate and a novel cellular mechanism as targets for the treatment of pathological pain. PMID:24369380

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

    Microsoft Academic Search

    Shixiang Yao; Shasha Chen; Dongsheng Xu; Haiyan Lan

    2010-01-01

    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)

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

    SciTech Connect

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

    2013-07-01

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

  8. Ideal Supercapacitor Behavior of Amorphous V 2O 5· nH 2O in Potassium Chloride (KCl) Aqueous Solution

    Microsoft Academic Search

    Hee Y. Lee; J. B. Goodenough

    1999-01-01

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

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

    PubMed Central

    Gulati, J; Babu, A

    1984-01-01

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

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

    PubMed

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

    McClure, Crystal

    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. 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.

  12. Electrocopolymerization of aniline and ortho-phenylenediamine via facile negative shift of polyaniline redox peaks

    Microsoft Academic Search

    Ali Parsa; Sulaiman Ab Ghani

    2008-01-01

    Oxidative electropolymerization of aniline (Ani) in phosphoric acid (H3PO4) on composite 2B pencil graphite was accomplished using selected inorganic salts as supporting electrolytes. These salts determined the degree of conductivity of polyaniline (PAni) formed. The conductivity was in the order of CaCl2>KCl>ZnCl2>ZnSO4>Ca3(PO4)2. The three pairs of redox peaks in the voltammogram of PAni formed in the presence of 0.06M Ca3(PO4)2

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

    PubMed

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

    2013-07-01

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

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

    PubMed Central

    Perez, Jose F.; Sanderson, Michael J.

    2005-01-01

    Increased resistance of airways or blood vessels within the lung is associated with asthma or pulmonary hypertension and results from contraction of smooth muscle cells (SMCs). To study the mechanisms regulating these contractions, we developed a mouse lung slice preparation containing bronchioles and arterioles and used phase-contrast and confocal microscopy to correlate the contractile responses with changes in [Ca2+]i of the SMCs. The airways are the focus of this study. The agonists, 5-hydroxytrypamine (5-HT) and acetylcholine (ACH) induced a concentration-dependent contraction of the airways. High concentrations of KCl induced twitching of the airway SMCs but had little effect on airway size. 5-HT and ACH induced asynchronous oscillations in [Ca2+]i that propagated as Ca2+ waves within the airway SMCs. The frequency of the Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained airway contraction. In the absence of extracellular Ca2+ or in the presence of Ni2+, the frequency of the Ca2+ oscillations declined and the airway relaxed. By contrast, KCl induced low frequency Ca2+ oscillations that were associated with SMC twitching. Each KCl-induced Ca2+ oscillation consisted of a large Ca2+ wave that was preceded by multiple localized Ca2+ transients. KCl-induced responses were resistant to neurotransmitter blockers but were abolished by Ni2+ or nifedipine and the absence of extracellular Ca2+. Caffeine abolished the contractile effects of 5-HT, ACH, and KCl. These results indicate that (a) 5-HT and ACH induce airway SMC contraction by initiating Ca2+ oscillations, (b) KCl induces Ca2+ transients and twitching by overloading and releasing Ca2+ from intracellular stores, (c) a sustained, Ni2+-sensitive, influx of Ca2+ mediates the refilling of stores to maintain Ca2+ oscillations and, in turn, SMC contraction, and (d) the magnitude of sustained airway SMC contraction is regulated by the frequency of Ca2+ oscillations. PMID:15928401

  15. pp and ?? intensity interferometry in collisions of Ar+KCl at 1.76A GeV

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    Results on pp, ?+?+, and ?-?- intensity interferometry are reported for collisions of Ar+KCl at 1.76 A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The experimental correlation functions as a function of the relative momentum are compared to model calculations allowing the determination of the space-time extent of the corresponding emission sources. The ?? source radii are found significantly larger than the pp emission radius. The present radii do well complement the beam-energy dependences of Gaussian source radii of the collision system of size A + A ? 40 + 40 . The pp source radius at fixed beam energy is found to increase linearly with the cube root of the number of participants. From this trend, a lower limit of the pp correlation radius is deduced.

  16. Spanish LLW and MLW disposal: durability of cemented materials in (Na, K)Cl simulated radioactive liquid waste.

    PubMed

    Goñi, S; Guerrero, A; Hernández, M S

    2001-01-01

    The microstructural stability or durability of a specific backfilling pozzolanic-cement mortar, which is employed in Spain, in concrete containers for the storage of low level liquid wastes (LLW) and medium level liquid wastes (MLW), has been studied by means of the Koch-Steinegger test at the temperatures of 20 and 40 degrees C during a period of 365 days. Mortar samples were immersed in salt solutions of 3.46 M NaCl and 3.46 M KCl to simulate the salinity of some radioactive liquid waste matrices. The resistance of the mortar to the saline solution attack is evaluated by the development of the relative flexural strength. The changes of the microstructure were followed by mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Pore solution was extracted and analyzed at different periods of time to know the possible diffusion of sodium, chloride and potassium inside the microstructure. PMID:11150135

  17. Regulatory volume increase in mammalian jejunal villus cells is due to bumetanide-sensitive NaKCl2 cotransport.

    PubMed

    MacLeod, R J; Hamilton, J R

    1990-05-01

    We assessed ion transport mechanisms operative during regulatory volume increase (RVI) in villus enterocytes isolated in suspension from guinea pig jejunum and examined with electronic cell sizing and 86Rb influx. After validation of the electronic-sizing technique with direct measurements of cell water, the response of cell volume to hypertonic media was evaluated in detail. When shrunk by exposure to hyperosmotic media (455 mosmol/kg medium) cells demonstrated a RVI that was complete in 20 min. RVI required extracellular Na+, K+, and Cl-; this cell swelling showed the following ion sensitivity; Na+ greater than Li+ greater than choline, K+ = Rb+, and Cl- greater than or equal to Br- greater than NO3- = acetate = gluconate. Bumetanide inhibition of villus cell swelling was concentration dependent from 10(-10) to 10(-5) M (7.0 +/- 4.5% vs. 87.8 +/- 0.3%); furosemide (10(-3)M) inhibited RVI (74.1 +/- 9.5%), but amiloride (10(-4) M) had little effect on cell swelling. Disulfonic stilbenes, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (10(-4) M), generated the same inhibition of RVI in either nominally HCO3(-)-free phosphate-buffered saline (PBS) or HCO3(-)-buffered PBS, suggesting anion exchange was not involved. Ouabain (10(-4) M) stimulated cell swelling. Hypertonic shrinkage increased the initial rate of bumetanide-sensitive 86Rb influx (80 +/- 38 vs. 1,011 +/- 241 pmol.mg protein-1.min-1; P less than 0.005) and required extracellular Na+ and Cl- (11 +/- 16 vs. 28 +/- 61 pmol.mg protein-1.min-1). RVI was prevented in low-K+ media (0.2 mM), but the addition of KCl initiated cell swelling. Our data strongly suggest that RVI in jejunal villus enterocytes occurs because of the hypertonic activation of NaKCl2 cotransport. PMID:2333994

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

    SciTech Connect

    Kassman, Haakan [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

    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)

  19. 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

    Friedman, Nir

    41 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 (all arrays in triplicate). Fitting the data in Table S1 using in the Hog1 induced network (273 genes in Fig. 1) together with ChIP data for comparison and Table S3 for all

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

    E-print Network

    Paris-Sud XI, Université de

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

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

    PubMed

    Ayyash, Mutamed M; Shah, Nagendra P

    2010-08-01

    The effect of partial substitution of NaCl with KCl on chemical composition, lactic bacterial count, and organic acids profile of Halloumi cheese was investigated. Halloumi cheeses were made and kept in 4 different brine solutions at 18% including NaCl only (HA), 3NaCl : 1KCl (HB), 1NaCl : 1KCl (HC), and 1NaCl : 3KCl (HD) and then stored at 4 degrees C for 56 d. No significant effect was observed between control and experimental cheeses in terms of moisture, fat, protein, lactic bacterial count, and pH values at the same storage period. There was a significant difference in ash, sodium, and potassium contents among experimental cheeses at the same storage period. Ash, sodium, and potassium contents increased significantly during storage at same salt treatment. There was no significant difference in lactic and citric acid contents among experimental cheeses and that of the control. In contrary, there was a significant difference in acetic acid among experimental cheeses. A strong positive correlation was observed between ash, Na, and K contents. An inverse correlation between organic acids and both Na and K contents was also observed. PMID:20722906

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed Central

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

    2013-01-01

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

  4. ROS activate KCl cotransport in nonadherent Ehrlich ascites cells but K+ and Cl- channels in adherent Ehrlich Lettré and NIH3T3 cells.

    PubMed

    Lambert, Ian Henry; Klausen, Thomas Kjaer; Bergdahl, Andreas; Hougaard, Charlotte; Hoffmann, Else Kay

    2009-07-01

    Addition of H(2)O(2) (0.5 mM) to Ehrlich ascites tumor cells under isotonic conditions results in a substantial (22 +/- 1%) reduction in cell volume within 25 min. The cell shrinkage is paralleled by net loss of K(+), which was significant within 8 min, whereas no concomitant increase in the K(+) or Cl(-) conductances could be observed. The H(2)O(2)-induced cell shrinkage was unaffected by the presence of clofilium and clotrimazole, which blocks volume-sensitive and Ca(2+)-activated K(+) channels, respectively, and is unaffected by a raise in extracellular K(+) concentration to a value that eliminates the electrochemical driving force for K(+). On the other hand, the H(2)O(2)-induced cell shrinkage was impaired in the presence of the KCl cotransport inhibitor (dihydro-indenyl)oxyalkanoic acid (DIOA), following substitution of NO(3)(-) for Cl(-), and when the driving force for KCl cotransport was omitted. It is suggested that H(2)O(2) activates electroneutral KCl cotransport in Ehrlich ascites tumor cells and not K(+) and Cl(-) channels. Addition of H(2)O(2) to hypotonically exposed cells accelerates the regulatory volume decrease and the concomitant net loss of K(+), whereas no additional increase in the K(+) and Cl(-) conductance was observed. The effect of H(2)O(2) on cell volume was blocked by the serine-threonine phosphatase inhibitor calyculin A, indicating an important role of serine-threonine phosphorylation in the H(2)O(2)-mediated activation of KCl cotransport in Ehrlich cells. In contrast, addition of H(2)O(2) to adherent cells, e.g., Ehrlich Lettré ascites cells, a subtype of the Ehrlich ascites tumor cells, and NIH3T3 mouse fibroblasts increased the K(+) and Cl(-) conductances after hypotonic cell swelling. Hence, H(2)O(2) induces KCl cotransport or K(+) and Cl(-) channels in nonadherent and adherent cells, respectively. PMID:19419998

  5. Composition of steam in the system NaCl-KCl-H2O-quartz at 600°C

    USGS Publications Warehouse

    Fournier, Robert O.; Thompson, J. Michael

    1993-01-01

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

  6. Microbiology of saturated salt solutions and other harsh environments. IV. New observations on ribonucleotide-induced recovery of KCl-habituated Penicillium notatum.

    PubMed

    Siegel, S M; Roberts, K

    1968-01-01

    Salt-tolerant mutant Penicillium notatum sub-cultured in a glucose-peptone broth saturated with KCl shows continued attenuated growth when transferred to salt-free broth. Additional tests have shown E. coli S-RNA to be inferior to yeast RNA preparations, that base-free phosphate sources are inactive, but that nicotinamide adenine dinucleotide and flavine adenine dinucleotide are moderately active. All phosphate derivatives of adenine, cytosine and guanosine and inosine were active including 5'-polyphosphates, 3'(2')-monophosphates 5'-monophosphates, and adenine 3', 5'-cyclic monophosphate. Uracil derivatives were of low activity at best. Among base precursors, orotic acid was moderately active whereas imidazoles were not. The high activity of inosine 5'-phosphate a precursor of other purine nucleotides suggested that one mode of KCl action might involve a block in conversion of 4-amino-5-imidazole carboxamide ribonucleoside to the hypoxanthine nucleotide. PMID:5638041

  7. Volatile products from the interaction of KCl(g) with Cr2O3 and LaCrO3 in oxidizing environments

    NASA Technical Reports Server (NTRS)

    Kohl, F. J.; Miller, R. A.; Stearns, C. A.; Fryburg, G. C.; Dillard, J. G.

    1977-01-01

    Cooled target collection techniques and high pressure mass spectrometric sampling were used to measure the relative rates of oxidative vaporization and to identify the volatile products emanating from samples of chromia and Mg-doped lanthanum chromite. The materials were exposed to partial pressures of KCl with and without H2O in one atmosphere of slowly flowing oxygen at elevated temperatures. Chromia and fresh samples of lanthanum chromite exhibited enhanced rates of oxidative vaporization upon exposure to these reactants. Mass spectrometric identification showed that the enhancements resulted from the heterogeneous formation of complex molecules of the type KCl sub 1,2,3 CrO3 and KOH sub l,2 CrO3. Lanthanum chromite that had undergone prolonged oxidative vaporization exhibited no enhanced oxidation upon exposure to the reactants.

  8. The presence of KCl in the exposure medium strongly influences the mutagenicity of metabolites of polycyclic aromatic hydrocarbons in Escherichia coli.

    PubMed

    Glatt, H; Staffa-Piée, A; Enders, N; Baidossi, W; Blum, J

    1994-07-01

    Previous studies demonstrated that the ion composition of the exposure medium may strongly influence the mutagenicity of many compounds in the liquid preincubation modification of the reversion assay with his- Salmonella typhimurium strains. Similar influences were now observed in the reversion assay with trp- Escherichia coli strain WP2 uvrA. The exposure medium was 8 mM sodium phosphate buffer (pH 7.4), containing no other ions or 125 mM KCl. Omission of KCl resulted in an about 10-fold enhancement of the mutagenic activity of 7-methylbenz[a]anthracene 5,6-oxide, but in a strong decrease in the mutagenicity of 1-hydroxymethylpyrene sulphate, close to the limit of detection. The findings with these two representative mutagens are very similar to those previously observed in S. typhimurium, suggesting that unobtrusive medium components may exert strong influences on the results with many test compounds in various bacterial test systems. PMID:7517509

  9. Effect of a smooth muscle relaxant from the stonefish, Synanceia trachynis, on KCl-induced responses in the guinea-pig vas deferens.

    PubMed

    Hoy, A W; Cameron, A M

    1986-09-23

    Stonefish skin secretion contains a smooth muscle relaxant, synancein II, that selectively inhibits tonic responses of KCl-induced contractions of the guinea-pig vas deferens. Synancein II (5-50 micrograms/ml) and nifedipine (10(-8)-10(-7) M) reduced tonic responses equally. Over these concentrations, synancein II inhibited phasic responses more than did nifedipine. Rapid inhibition of phasic responses by synancein II (low concentrations) but its inability to block this response at high concentrations suggests that more than one extracellular and/or intracellular Ca2+ source may contribute to the generation of the phasic response. Some calcium antagonists selectively inhibit tonic responses induced by KCl in many different organs, whilst others inhibit phasic responses. Whereas we previously reported that synancein II selectively inhibits phasic rather than tonic responses in the guinea-pig ileum, the present results reveals a reversal of this selectivity. PMID:3770070

  10. ESR study of the librations of O2 defects in NaClO3 and KClO4 single crystals

    NASA Astrophysics Data System (ADS)

    Bjerre, Nis

    1982-04-01

    The ESR spectra of O2 defects in UV-irradiated single crystals of NaClO3 and KClO4 were measured at 9 and 35 GHz in the temperature range 2.7-23 K. The O2 defect in NaClO3 has a g-tensor close to that of the free molecule and exhibits well-resolved 16O2-18O2 isotope shifts. Model calculations reproducing these shifts reveal that the discrepancy between the spin Hamiltonians of the trapped and the free molecule mainly results from the angular librations of the trapped molecule. The marked temperature dependence of the spin Hamiltonian of an O2 defect in KClO4 is accounted for in terms of fast transitions between the librational states.

  11. The K-Cl cotransporter KCC3 as an independent prognostic factor in human esophageal squamous cell carcinoma.

    PubMed

    Shiozaki, Atsushi; Takemoto, Kenichi; Ichikawa, Daisuke; Fujiwara, Hitoshi; Konishi, Hirotaka; Kosuga, Toshiyuki; Komatsu, Shuhei; Okamoto, Kazuma; Kishimoto, Mitsuo; Marunaka, Yoshinori; Otsuji, Eigo

    2014-01-01

    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

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

    SciTech Connect

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

    1994-11-01

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

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

    PubMed Central

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

    2003-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  15. Resonance Raman scattering and optical absorption studies of MnO-4 in KClO4 at high pressure

    NASA Astrophysics Data System (ADS)

    Khodadoost, B.; Lee, Scott A.; Page, J. B.; Hanson, R. C.

    1988-09-01

    We have measured the pressure dependence of both the optical absorption and the resonance Raman (RR) excitation profiles of the breathing mode, ?1, and its first two overtones for the substitutional impurity ion MnO-4, in crystalline KClO4. We have used the powerful transform technique of the time-correlator theory of RR scattering to analyze our RR data by calculating the profile line shapes directly from the measured optical absorption. This work constitutes the first successful application of the transform technique to the domain of high-pressure physics. The optical absorption displays a blue shift with increasing pressure, and both the ground- and excited-electronic-state vibrational frequencies increase with pressure. We calculate the renormalized Stokes loss parameter of ?1 directly from ratios of the scaling factors used in fitting our calculated profile line shapes to the data. This ``direct'' transform method presumes the broadening mechanisms to be homogeneous, and it gives a decrease in the renormalized Stokes loss parameter of less than 10% between one atmosphere and 10.6 GPa. We have also used a previously developed extension of the time-correlator theory to incorporate inhomogeneous broadening in the transform calculations. These calculations show that the effect of inhomogeneous broadening is not significant on the RR profile line shapes, but indicate that the decrease in the renormalized Stokes loss parameter with pressure could be as large as 15%.

  16. Investigation of the dissolution of CaCrO/sub 4/ in molten LiCl-KCl eutectic

    SciTech Connect

    Guidotti, R.A.; Reinhardt, F.W.; Tallant, D.R.; Higgins, K.L.

    1984-06-01

    The rate of dissolution of CaCrO/sub 4/ in molten LiCl-KCl eutectic was measured by laser Raman spectroscopy after attempts at direct sampling of the melt and cyclic voltammetry proved unsuccessful. Increasing the calcining temperature of the CaCrO/sub 4/ prepared by General Electric Co., Neutron Devices Dept. (GENDD), for use in Ca/CaCrO/sub 4//Fe thermal batteries resulted in an increase in the average particle size, with a concomitant reduction in the rate of dissolution in the molten eutectic. CaCrO/sub 4/ obtained from a commercial supplier was found to contain a component that was resistant to dissolution in the molten eutectic; this resistance caused the commercial product to be less reactive than the GENDD-prepared CaCrO/sub 4/ in Ca/CaCrO/sub 4//Fe thermal batteries. Catholyte mixes formulated with characterized CaCrO/sub 4/ samples were tested in batteries under various load conditions. The performance of batteries containing the finely divided GENDD CaCrO/sub 4/ was inferior under light-load conditions to that of batteries with coarser material. The poor performance was the result of enhanced dissolution kinetics of the finer CaCrO/sub 4/, which caused greater generation of heat from chemical reactions at the anode.

  17. Epifluorescence optical microscopy: a sensitive tool for determining the spatial distribution of europium-dihalide precipitates in KCl : KBr : Eu crystals

    Microsoft Academic Search

    A. E. Cordero-Borboa; L. F. Jiménez-García

    2005-01-01

    The spatial distribution of europium-dihalide-type precipitates in KCl?:?KBr?:Eu single crystals annealed at 200°C for long periods of time was determined by epifluorescence optical microscopy. Laue-type patterns and optical spectroscopy were used to test the degree of long-range ordering of the specimens and to monitor the precipitation during annealing, respectively. Precipitates smaller than about 0.08?µm were found (2.84?×?10 precipitates cm) all

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

    Microsoft Academic Search

    P. K. Lauf

    1988-01-01

    The stimulatory effects of two thiol (SH) group oxidants, methylmethane thiosulfonate (MMTS) and diazene dicarboxylic acid bis [N,N-dimethylamide] (diamide), on the kinetics of ouabain-resistant (OR) K:Cl [co]-transport in low K (LK) sheep red blood cells were compared with the effects of alkylating agents, notably N-ethylmaleimide (NEM). At low concentrations, both MMTS and diamide stimulated K:CI [co]-transportv and with a latency

  19. Electrochemical and Thermodynamic Properties of EuCl3 and EuCl2 in an Equimolar NaCl-KCl Melt

    NASA Astrophysics Data System (ADS)

    Kuznetsov, S. A.; Rycerz, L.; Gaune-Escard, M.

    2001-11-01

    The electroreduction of EuCl3 in an equimolar NaCl-KCl mixture was studied at 973 -1123 K by different electrochemical methods. This reduction of Eu(III) in NaCl-KCl melt occurs via two successive reversible steps involving transfer of one and two electrons. The diffusion coefficients of Eu(III) and Eu(II) were measured by linear sweep voltammetry and chronopotentiometry. The values found by these methods are in a good agreement. The standard rate constants for the redox reaction Eu(III) + e~ Eu(II) were calculated from cyclic voltammetry data. The sluggish kinetics of this reaction is discussed in terms of substantial rearrangement of the europium coordination sphere. Special attention was paid to the choice of working electrodes for the study of electrode reactions. The formal standard potentials E*E u (^ /Ba, E* eU (hr/eu and the formal redox potentials ^*Eu(ni)/Eu(ii) were determined from open-circuit potentiometry and linear sweep voltammetry data. The free Gibbs energy changes for the reaction EuCl3(so1) EuCl2(SOi.) + 1/2 Cl2(g.) and the equilibrium constants of the metal-salt reaction 2Eu(III) + Eu 3 Eu(II) were calculated. The thermodynamics of the formation of dilute solutions of europium di-and trichloride in an equimolar NaCl-KCl melt were determined. It was shown that electrochemical transient techniques give the possibility of the determination of the relative partial molar mixing enthalpy of europium trichloride and dichloride in NaCl-KCl melt.

  20. Functional role of RNA polymerase II and P70 S6 kinase in KCl withdrawal-induced cerebellar granule neuron apoptosis.

    PubMed

    Padmanabhan, Jaya; Brown, Kristy R; Padilla, Amelia; Shelanski, Michael L

    2015-02-27

    KCl withdrawal-induced apoptosis in cerebellar granule neurons is associated with aberrant cell cycle activation, and treatment with cyclin-dependent kinase (Cdk) inhibitors protects cells from undergoing apoptosis. Because the Cdk inhibitor flavopiridol is known to inhibit RNA polymerase II (Pol II)-dependent transcription elongation by inhibiting the positive transcription elongation factor b (P-TEFb, a complex of CDK9 and cyclin T), we examined whether inhibition of RNA Pol II protects neurons from apoptosis. Treatment of neurons with 5, 6-dichloro-1-?-D-ribobenzimidazole (DRB), an RNA Pol II-dependent transcription elongation inhibitor, and flavopiridol inhibited phosphorylation and activation of Pol II and protected neurons from undergoing apoptosis. In addition to Pol II, neurons subjected to KCl withdrawal showed increased phosphorylation and activation of p70 S6 kinase, which was inhibited by both DRB and flavopiridol. Immunostaining analysis of the neurons deprived of KCl showed increased nuclear levels of phospho-p70 S6 kinase, and neurons protected with DRB and flavopiridol showed accumulation of the kinase into large spliceosome assembly factor-positive speckle domains within the nuclei. The formation of these foci corresponded with cell survival, and removal of the inhibitors resulted in dispersal of the speckles into smaller foci with subsequent apoptosis induction. Because p70 S6 kinase is known to induce translation of mRNAs containing a 5'-terminal oligopyrimidine tract, our data suggest that transcription and translation of this subset of mRNAs may contribute to KCl withdrawal-induced apoptosis in neurons. PMID:25568312

  1. Refractive indexes and electronic polarizabilities of molten HoCl 3–NaCl and HoCl 3–KCl mixtures

    Microsoft Academic Search

    Kazuya Shirao; Takuma Iida; Kazuko Fukushima; Yasuhiko Iwadate

    1998-01-01

    The refractive indexes of molten HoCl3–NaCl and HoCl3–KCl mixtures were measured by goniometry using visible light at eight wavelengths and expressed as functions of both temperature and wavelength into empirical formulas by a least-squares method. The electronic polarizabilities of ions in the mixture melts were obtained from the data of refractive indexes and molar volumes, and the polarizability of a

  2. Calcite Solubility in H2O-KCl-NaCl-LiCl Solutions at 700 °C and 8 kbar: Experimental Determination and Modeling

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The calcium carbonate (CaCO3) minerals calcite and aragonite are the primary reservoir for oxidized carbon in the continental crust and upper mantle, and are the dominant carriers of carbon into the Earth's interior. Their solubility in subduction zone fluids strongly influences the amount of carbon retained in downgoing lithosphere. Previous work suggests modest solubility in pure H2O, but high solubility in NaCl-H2O solutions; however, natural solutions may contain additional cations such as KCl. We evaluated the role of salt on calcite solubility in salt-H2O solutions involving NaCl, KCl, LiCl and CsCl. All experiments were conducted in a piston-cylinder apparatus at 700 °C and 8 kbar. These conditions were used because pressure is not expected to have a large effect on the nature of calcite dissolution in saline fluids. Results show that increasing the concentration of any salt exponentially increases calcite solubility for all salt-H2O and mixed salt-H2O solutions. At a given salt mole fraction in one-salt solutions, calcite solubility increases with decreasing salt cation size: CsCl<KClKCl-NaCl-LiCl solution. The model reproduces the data in two-salt and three-salt solutions with an average deviation of 6% and 1% respectively. This study shows that aqueous fluids with high concentrations of halide salts have the potential to promote substantial carbon mass transfer. With the growing evidence for highly saline brines in a range of high pressure geologic environments, these fluids may play an important role in the deep carbon cycle.

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

    SciTech Connect

    Yagnik, S.K.

    1982-09-01

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

  4. Comparison of KCl denuders with the pyrolysis method and calibration using HgBr2 at an in-service AMNET site

    NASA Astrophysics Data System (ADS)

    McClure, C.; Jaffe, D. A.; Edgerton, E.; Jansen, J. J.

    2013-12-01

    During the summer of 2013, we initiated a project to examine the performance of Tekran measurements of Gaseous Oxidized Mercury (GOM) with a pyrolysis method at the North Birmingham SEARCH site. Measurements started in June 2013 and will run until September 2013. This project responds to recent studies that indicate problems with the KCl denuder method for collection of GOM (e.g. Lyman et al., 2010; Gustin et al., 2013; Ambrose et al., 2013). For this project, we compared two GOM measurement systems, one using the KCl denuder method and a second method using high temperature pyrolysis of Hg compounds and detection of the resulting Hg0 vapors. Both instruments were also calibrated using an HgBr2 source to understand the recovery of one possible atmospheric GOM constituent. Both instruments sampled from a common, heated manifold. Past work has shown that in order to fully transmit HgBr2 sample lines must be made from PFA lines and heated to 100 °C. The transmission rate of HgBr2 during this project is approximately 90% over 25 feet of sample tubing at this temperature. Very preliminary results from this study have found that the transmitted HgBr2 is captured with 95% efficiency in carbon-scrubbed ambient air for both the KCl denuder and the pyrolysis method. However, the denuder method appears to be significantly less efficient in the capture of GOM when sampling unaltered ambient air versus the pyrolysis validation of total Hg0. Therefore, calibration of GOM measurements is essential in order to accurately correct for fluctuations in the GOM capture efficiency. We have also found that calibrations for GOM can be done routinely in the field and that these are essential to fully understand the GOM measurements. At present our calibration system is performed manually, but in principle this method could be readily automated.

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

    PubMed Central

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

    2015-01-01

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

  6. The Effects of KCl, K 2 SO 4 and K 2 CO 3 on the High Temperature Corrosion of a 304Type Austenitic Stainless Steel

    Microsoft Academic Search

    Jesper Pettersson; Nicklas Folkeson; Lars-Gunnar Johansson; Jan-Erik Svensson

    2011-01-01

    The oxidation of 304-type (Fe18Cr10Ni) austenitic stainless steel was investigated at 500 and 600 °C in 5% O2 + 40% H2O. Prior to exposure the samples were sprayed with KCl, K2CO3 or K2SO4, the amount of salt corresponding to 1.35 ?mol K+\\/cm2. For reference, salt-free samples were exposed in 5% O2 + 40% H2O and in 5% O2 (N2 was used as carrier gas). The oxidized samples

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

    NASA Astrophysics Data System (ADS)

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

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

  8. Primary radiation-induced electron-excess defects and the formation of O - 3 in KClO4 and KBrO4 investigated by ESR

    NASA Astrophysics Data System (ADS)

    Byberg, J. R.

    1981-09-01

    The ESR spectra of primary electron-excess defects in KClO4 and KBrO4 crystals irradiated with x rays at 26 K indicate that trapping of electrons on ClO-4 leads to immediate expulsion of O-, whereas BrO-4 may accept an excess electron, forming a doubly charged anion BrO2-4. The thermally activated formation of O-3 involves in both cases addition of O2 to the primary electron-excess defects. Hence, BrO2-4 is chemically equivalent to O-.

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

    SciTech Connect

    Ammon Williams; Supathorn Phongikaroon; Michael Simpson

    2013-02-01

    A parametric study has been conducted to identify the effects of several parameters on the separation of CsCl from molten LiCl-KCl salt via a melt crystallization process. A reverse vertical Bridgman technique was used to grow the salt crystals. The investigated parameters were: (1) the advancement rate, (2) the crucible lid configuration, (3) the amount of salt mixture, (4) the initial composition of CsCl, and (5) the temperature difference between the high and low furnace zones. From each grown crystal, samples were taken axially and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Results show that CsCl concentrations at the top of the crystals were low and increased to a maximum at the bottom of the salt. Salt (LiCl-KCl) recycle percentages for the experiments ranged from 50% to 75% and the CsCl composition in the waste salt was low. To increase the recycle percentage and the concentration of CsCl in the waste form, the possibility of using multiple crystallization stages was explored to further optimize the process. Results show that multiple crystallization stages are practical and the optimal experimental conditions should be operated at 5.0 mm/hr rate with a lid configuration and temperature difference of 200 °C for a total of five crystallization stages. Under these conditions, up to 88% of the salt can be recycled.

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

    SciTech Connect

    K. C. Marsden; B. Pesic

    2011-04-01

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

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

    SciTech Connect

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

    2008-04-22

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

  12. CO 2 reaction with Ca(OH) 2 during SO 2 removal with convective pass sorbent injection and high temperature filtration

    Microsoft Academic Search

    Guang G. Li; Tim C. Keener; Antoinette W. Stein; Soon J. Khang

    2000-01-01

    The Kyoto Protocol calls for greenhouse gas emission reductions which could affect the use of coal for producing electricity. Carbon credits are being explored as a method for countries to meet their reduction commitments. Carbon dioxide removal in flue gas desulfurization (FGD) systems should be considered if and when the concept of carbon credits are implemented. This paper addresses the

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

    USGS Publications Warehouse

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

    1990-01-01

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

  14. Synthetic fluid inclusions. V. Solubility relations in the system NaCl-KCl-H 2O under vapor-saturated conditions

    NASA Astrophysics Data System (ADS)

    Sterner, S. Michael; Hall, Donald L.; Bodnar, Robert J.

    1988-05-01

    Vapor-saturated solubility relationships in the system NaCl-KCl-H 2O have been determined by experimentally synthesizing fluid inclusions in quartz in the presence of known brine compositions and then measuring the dissolution temperatures of halite and/or sylvite daughter crystals within the inclusions using a microscope equipped with a heating stage. These data, along with other literature values have been used in a stepwise multiple regression routine to generate a series of equations describing vapor-saturated solubility relations within the halite, sylvite and hydrohalite stability fields. These equations, together with a recently published equation for the ice stability field ( HALLet al., 1987), have been used to construct the complete vapor-saturated solubility surface in the NaCl-KCl-H 2O ternary system. The diagram may be used in the interpretation of microthermometric data to determine the compositions of fluid inclusions approximated by the NaCl-KCl-H 2O system. For the NaCl-H 2O binary system, the ternary halite field expression reduces to Wt.% NaCl = 26.242 + 0.4928 ? + 1.42 ?2 - 0.223 ?3 + 0.04129 ?4 + 0.006295 ?5- 0.001967 ?6 + 0.0001112 ?7 ( ? = T° C/100, where 0.1° ? T° C ?801° C) which describes halite solubilities along the three-phase halite + liquid + vapor (H + L + V) curve. Similarly, sylvite solubilities along the three-phase sylvite + liquid + vapor (S + L + V) curve are described by the equation Wt.% KC1 = 21.886 + 20.28 ? - 9.603 ?2 + 4.078 ?3 - 0.8724 ?4 + 0.09174 ?5 - 0.003776 ?6 ( ?= T° C/100, where -10.7° ? T° C ? 770° C). Solubility data obtained from synthetic fluid inclusions are in good agreement with recently published data for the KC1-H 2O and NaCl-H 2O binary systems but are at variance with some earlier works.

  15. Discharge characteristics of lithium-boron alloy anode in molten salt thermal cells. [Li-B/LiCl-KCl/FeS/sub 2/ depolarizer/Fe

    SciTech Connect

    Szwarc, R.; Walton, R.D.

    1980-03-31

    Thermal cells comprised of Li-B anodes, LiCl-KCl eutectic electrolyte, and one of three depolarizers, CaCrO/sub 4/, Li/sub 2/CrO/sub 4/, or FeS/sub 2/, 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 as other cell components. Of the three systems investigated, the Li-B/FeS/sub 2/ combination is most promising for primary thermal batteries, particularly for long-life power designs. 12 figures, 1 table.

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

    SciTech Connect

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

    1993-09-01

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

  17. Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76 A GeV

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)0 are reported for collisions of Ar + KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)0 production probability per central collision of P_{K^{*0}}=(4.4± 1.1 ± 0.5)× 10^{-4} and the K*(892)0/K0 ratio of P_{K^{*0}}/P_{K^0}=(1.9± 0.5± 0.3)× 10^{-2} are determined at the lowest energy so far ( i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, sqrt{s_{NN}}-sqrt{s_{thr}}=-340 MeV). The K*0/K0 ratio is compared with results of other experiments and with the predictions of the UrQMD transport approach and of the statistical hadronization model. The experimental K*0 yield and the K*0/K0 ratio are overestimated by the transport model by factors of about five and two, respectively. In a chemically equilibrated medium the ratio corresponds to a temperature of the thermalized system being systematically lower than the value determined by the yields of the stable and long-lived hadrons produced in Ar + KCl collisions. From the present measurement, we conclude that sub-threshold K* production either cannot be considered to proceed in a system being in thermal equilibrium or these short-lived resonances appear undersaturated, for example as a result of the rescattering of the decay particles in the ambient hadronic medium.

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

    PubMed Central

    Kline, Loren W; Karpinski, Edward

    2015-01-01

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

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

    Microsoft Academic Search

    Torben Smith Sørensen

    1995-01-01

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

  20. Vapour pressures of H 2 16O and H 2 18O, and saturated aqueous solutions of KCl from T=298 K to T=318 K by the isoteniscopic method

    Microsoft Academic Search

    Alexander Apelblat

    1998-01-01

    Vapour pressures of normal water, water enriched by the heavy isotope of oxygen H218O, and saturated aqueous solutions of KCl were determined in the temperature range (298 to 318)K by the isoteniscopic method and compared with the literature data. Water activities, osmotic coefficients, vapour pressure lowerings, boiling point elevations, and molar enthalpies of vaporization at the saturation point of potassium

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

    PubMed

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

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Stani?, Vojislav; Dimitrijevi?, Suzana; Antonovi?, Dušan G.; Joki?, Bojan M.; Zec, Slavica P.; Tanaskovi?, Sladjana T.; Rai?evi?, Slavica

    2014-01-01

    Synthetic biomaterials based on fluorine substituted hydroxyapatite are potentially attractive for orthopedic and dental implant applications. The new synthesis of fluorine substituted hydroxyapatite samples were done by neutralization, which consists of adding the solution of HF and H3PO4 in suspension of Ca(OH)2. Characterization studies from XRD, SEM and FTIR spectra showed that crystals are obtained with apatite structure and those particles of all samples are nano size, with an average length of 80 nm and about 15-25 nm in diameter. The central composite design was used in order to determine the optimal conditions for the antimicrobial activity of the synthesized samples. In order to evaluate the influence of operating parameters on the percent of viable cell reduction of Streptococcus mutans, three independent variables were chosen: exposure time, pH of saline and floride concentration in apatite samples. The experimental and predicted antimicrobial activities were in close agreement. Antimicrobial activity of the samples increases with the increase of fluoride concentration and the decreased pH of saline. The maximum antimicrobial activity was achieved at the initial pH of 4.

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

    NASA Astrophysics Data System (ADS)

    Stani?, Vojislav; Radosavljevi?-Mihajlovi?, Ana S.; Živkovi?-Radovanovi?, Vukosava; Nastasijevi?, Branislav; Marinovi?-Cincovi?, Milena; Markovi?, Jelena P.; Budimir, Milica D.

    2015-05-01

    Silver doped fluorapatite nanopowders were synthesised by neutralization method, which consists of dissolving Ag2O in solution of HF and H3PO4 and addition to suspension of Ca(OH)2. The powder XRD, SEM and FTIR studies indicated the formation of a fluorapatite nanomaterials with average length of the particles is about 80 nm and a width of about 15 nm. The FTIR studies show that carbonate content in samples is very small and carbonte ions substitute both phosphate and hydroxyl groups in the crystal structure of samples, forming AB-type fluorapatite. Antibacterial studies have demonstrated that all Ag+-doped fluorapatite samples exhibit bactericidal effect against pathogens: Staphylococcus aureus, Micrococcus luteus and Kllebsiela pneumoniae. Antibacterial activity increased with the increase of Ag+ in the samples. The atomic force microscopy studies revealed extensive damage to the bacterial cell envelops in the presence of Ag+-doped fluorapatite particles which may lead to their death. The synthesized Ag+-doped fluorapatite nanomaterials are promising as antibacterial biomaterials in orthopedics and dentistry.

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

    PubMed

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

    2014-01-28

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

  5. Evaluation of the physical and antimicrobial properties of silver doped hydroxyapatite depending on the preparation method.

    PubMed

    Dubnika, Arita; Loca, Dagnija; Salma, Ilze; Reinis, Aigars; Poca, Lasma; Berzina-Cimdina, Liga

    2014-02-01

    In the present study, the effect of the preparation method on the physical and antibacterial properties of silver doped hydroxyapatite (HAp/Ag) samples was investigated. HAp/Ag with 0.1-5 % of silver was prepared using two different modified wet chemical precipitation methods. A comparison of thermal stability and thermodynamical properties indicated that the thermal stability and sintering temperature of HAp/Ag were higher than those of pure hydroxyapatite if Ca(NO3)2·4H2O, AgNO3, NH4OH and (NH4)2HPO4 were used as raw materials. Phase composition and silver release were determined by XRD and ICP-MS. The study showed that, after 50 h in simulated body fluid 0.8-1.8 % of silver of the total silver amount was released from compact HAp/Ag scaffolds, and release kinetics strongly depended on the HAp/Ag preparation method. In vitro antibacterial activity of samples from each method against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa was approved. Results showed that, in the case of using Ca(OH)2, H3PO4 and AgNO3 as raw materials for HAp/Ag synthesis, higher antibacterial activity towards both bacterial strains could be obtained. PMID:24170340

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

    PubMed Central

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

    2012-01-01

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

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

    SciTech Connect

    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

    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.

  8. Electrochemical impedance spectroscopy study of a hydrogen electrode reaction at a Zn electrode in a molten LiCl-KCl-LiH system.

    PubMed

    Nakajima, Hironori; Nohira, Toshiyuki; Ito, Yasuhiko

    2005-05-19

    The hydrogen electrode reaction involving hydride ion, H-, at a Zn electrode is investigated in a molten LiCl-KCl-LiH system at 673 K. The charge-transfer resistances were measured by electrochemical impedance spectroscopy in the overpotential region of 0.10 < or = eta < or = 0.35 V and over the H- concentrations of 1.5 x 10(-4) < or = C(H)- < or = 1.2 x 10(-3) mol cm(-3). The logarithm plot of the charge-transfer resistance against the overpotential at C(H)- = 3.0 x 10(-4) mol cm(-3) gives the symmetry factor, beta, of 0.50 and the exchange current density, j0, of 5.8 x 10(-3)A cm(-2), respectively. Analysis of the dependence of j0 on H- concentration independently gives a beta of 0.55. The reasonable beta values indicate that the H- <==> H(ad)(M) + e- step is rate-determining. PMID:16852161

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

    PubMed

    Kline, Loren W; Karpinski, Edward

    2014-01-01

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

  10. Phase analysis of Bi sbnd Ca sbnd Sr sbnd Cu sbnd O superconducting films at different growth temperatures from KCl supercooled solutions

    NASA Astrophysics Data System (ADS)

    Raina, Kanwal K.; Narayanan, S.; Pandey, R. K.

    1993-03-01

    Films of 80 K phase of BiCaSrCu-oxide superconductor referred as BCSCO have been grown from KCl-Bi2CaSr2Cu2O8+? solutions at different growth temperature regimes by the LPE process. Twin-free single crystal substrates of NdGaO3 with (001) orientation are used for growing these films. The temperature range of 850-830°C is found to be the most favorable region for the formation of the 2122 phase of BCSCO. Above 850°C up to the peritectic melting point of the 2122 phase (885°C), formation of the 2122 phase is highly suppressed with the separation of Bi2CaSr2Cu2O8+? into 2021, calcium copper oxide (Ca2CuO3 and CaCu2O3) and other non-superconducting phases. X-ray powder diffraction analysis is used to identify different phases of BCSCO films. Morphological examination of the films is carried out by scanning electron microscopy. The onset of transition of the 2122 phase films is observed at 90 K and zero resistance is reached at 83 K. Post-growth annealing has an adverse effect on the superconducting properties of the films.

  11. 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

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

    2014-01-01

    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. PMID:25419384

  12. A Molecular Dynamics Simulation of the Electric and Thermodynamic Properties in Molten (Nd1/3, Na or K)Cl Mixtures

    NASA Astrophysics Data System (ADS)

    Matsumiya, Masahiko; Takagi, Ryuzo

    2001-07-01

    Molecular dynamics simulations have been carried out on molten (Nd1/3, K)Cl at 1065 and 1073 K and (Nd1/3, Na)Cl at 1124 K for various compositions. The calculated self-exchange velocity (v ), self-diffusion coefficient (D), electrical conductivity (k) and enthalpy of mixing ( ?Hmix) were compared with the corresponding experimental values. The calculated results revealed that v and D of potassium decrease with increasing anmount of neodymium, as expected from the experimental internal mobility (6). The decrease of bK, vK, and DK are attributed to the tranquilization effect by Nd3+ which strongly interacts with Cl- as well as Dy3+. On the contrary, bNd, VNd, and DNd increase with increasing concentration of Nd3+. This might be ascribed to the stronger association of Nd3+ with Cl- due to the enhanced charge asymmetry of the two cations neighboring Cl- . In addition, the sequences of the calculated v's, D's and k 's for the various compositions were consistent with those of the known experimental results. The experimental enthalpy of mixing with its negative dependence on the cation size was qualitatively reproduced.

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

    PubMed

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

    2012-09-27

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

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

    PubMed Central

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

    2011-01-01

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

  15. Brain-Derived Neurotrophic Factor–Mediated Downregulation of Brainstem K+–Cl– Cotransporter and Cell-Type–Specific GABA Impairment for Activation of Descending Pain Facilitation

    PubMed Central

    Zhang, Zhi; Wang, Xinxing; Wang, Wei; Lu, Yun-Gang

    2013-01-01

    Chronic pain is thought to be partly caused by a loss of GABAergic inhibition and resultant neuronal hyperactivation in the central pain-modulating system, but the underlying mechanisms for pain-modulating neurons in the brain are unclear. In this study, we investigated the cellular mechanisms for activation of brainstem descending pain facilitation in rats under persistent pain conditions. In the nucleus raphe magnus (NRM), a critical relay in the brain’s descending pain-modulating system, persistent inflammatory pain induced by complete Freund’s adjuvant decreased the protein level of K+–Cl? cotransporter (KCC2) in both total and synaptosomal preparations. Persistent pain also shifted the equilibrium potential of GABAergic inhibitory postsynaptic current (EIPSC) to a more positive level and increased the firing of evoked action potentials selectively in ?-opioid receptor (MOR)–expressing NRM neurons, but not in MOR-lacking NRM neurons. Microinjection of brain-derived neurotrophic factor (BDNF) into the NRM inhibited the KCC2 protein level in the NRM, and both BDNF administration and KCC2 inhibition by furosemide mimicked the pain-induced effects on EIPSC and excitability in MOR-expressing neurons. Furthermore, inhibiting BDNF signaling by NRM infusion of tyrosine receptor kinase B–IgG or blocking KCC2 with furosemide prevented these pain effects in MOR-expressing neurons. These findings demonstrate a cellular mechanism by which the hyperactivity of NRM MOR-expressing neurons, presumably responsible for descending pain facilitation, contributes to pain sensitization through the signaling cascade of BDNF-KCC2-GABA impairment in the development of chronic pain. PMID:23847084

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

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

    SciTech Connect

    S. Frank

    2009-09-01

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

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

    NASA Technical Reports Server (NTRS)

    Holy, John A.

    1993-01-01

    The burn rates of the pyrotechnic TiH2/KClO4/Viton with a mass ratio of 30/65/5 have been measured as a function of pressure in nitrogen up to 312 MPa(45 Kpsi). The burn rates were fit to R = a pn, with a = 2.055 cm/sec/MPan and n = 0.472 between 0.15 MPa (22 psi) and 21.6 MPa (3.13 Kpsi) and a = 4.38 cm/sec/MPan and n = 0.266 between 70 MPa (10.15 Kpsi) and 312 MPa (45.25 Kpsi). The decrease in slope at the higher pressures is attributed to a diffusion limited reaction. No acoustically driven flame instabilities or large conductive-to-convective burn transitions were observed. Solid reaction products were analyzed by x-ray diffraction and scanning electron microscopy (SEM). X-ray diffraction detected only TiO2 and KC1. SEM showed that the particle size of the reaction products increased as the nitrogen pressure increased. There were no anomalous characteristics of the burn of this pyrotechnic that could be interpreted as a cause of the o-ring blow-by problem in the forward shear bolt assembly. Three NASA SKD26100098-301 pressure cartridges were fired into a fixed volume vessel that was sealed with an O-ring. A maximum pressure of 181.7 MPa(26,350 psi) was reached in around 100 ,mu sec for two shots fired into a volume of 16.3 cm3(0.996 in3). A maximum pressure of 33,460 psi was reached for one shot fired into a volume of 9.55 cm3(0.583 in3). The O-ring burned through on one shot in the larger volume and leaked on the other two thereby simulating the effects of an O-ring leak. The results imply that the piston in the shear bolt assembly would receive a large impulse even if there was a leak in an O-ring seal.

  19. The effect of NaCl substitution with KCl on proteinase activities of cell-free extract and cell-free supernatant at different pH levels and salt concentrations: Lactobacillus acidophilus and Lactobacillus casei.

    PubMed

    Ayyash, M M; Sherkat, F; Shah, N P

    2013-01-01

    The aim of this study was to investigate the effect of substitution of NaCl with KCl at different pH levels and salt concentrations on proteinase activity of cell-free extract and cell-free supernatant of the probiotics Lactobacillus acidophilus and Lactobacillus casei. de Man, Rogosa, and Sharpe broth aliquots were mixed with 2 pure salts (NaCl and KCl) and 2 salt concentrations at 2 concentration levels (5 and 10%), inoculated with Lactobacillus acidophilus or Lactobacillus casei, and incubated aerobically at 37°C for 22 h. The cultures were then centrifuged at 4,000×g for 30 min, and the collected cell pellets were used to prepare cell-wall proteinases and the supernatants used as a source of supernatant (extracellular) proteinases. The proteolytic activity and protein content of both portions were determined. After incubation of both portions with 3 milk caseins (?-, ?-, ?-casein), the supernatants were individually subjected to analysis of angiotensin-converting enzyme (ACE)-inhibitory activity and proteolytic activity using the o-phthalaldehyde method. Significant differences were observed in ACE-inhibitory and proteolytic activities between salt substitution treatments of cell-free extract and cell-free supernatant from both probiotic strains at the same salt concentration and pH level. PMID:23084889

  20. Formation of complex defects involving molecular oxygen by electron-hole reactions in x-irradiated KClO4 and KBrO4, studied by ESR and IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Bjerre, Nis; Byberg, J. R.

    1985-03-01

    Complex defects of composition [XO-2, O2], X=Cl, Br, produced by UV or x-irradiation of solid KClO4 and KBrO4 at 26 K are characterized by ESR and IR spectroscopy. [XO-2, O2] is shown to arise during x-irradiation in a reaction between self-trapped electrons in the form of XO2-4 defects, and self-trapped holes in the form of (XO4)-2 defects. The previously described hole defect [XO2, O2] is shown to arise from oxidation of [XO-2, O2] by reaction with (XO4)-2. Thus all the abundant defects observed in x-irradiated KClO4 and KBrO4 stem from self-trapping of electrons and holes and from simple reactions of the self-trapped electrons and holes. The observed equivalence of optical excitation of the anions with electron-hole recombination may be a general property of polyatomic solids.

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

    E-print Network

    Sparks, Donald L.

    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. Ranking of amendments based on total P desorbed was HCl + K3PO4 > H3PO4 > HA > untreated soil, while

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  3. The effect of NaCl substitution with KCl on Akawi cheese: chemical composition, proteolysis, angiotensin-converting enzyme-inhibitory activity, probiotic survival, texture profile, and sensory properties.

    PubMed

    Ayyash, M M; Sherkat, F; Shah, N P

    2012-09-01

    The effect of partial substitution of NaCl with KCl on Akawi cheese with probiotic bacteria was investigated during 30 d of storage at 4 °C. Chemical composition, the survival of probiotic and lactic acid bacteria, proteolytic activity, and texture profile analysis were analyzed and sensory analysis was carried out to determine the effects of substitution. No significant differences were observed in moisture, protein, fat, and ash contents among the experimental Akawi cheeses at the same storage period. Significant differences were observed in water-soluble nitrogen and phosphotungstic-soluble nitrogen between experimental cheeses at the same of storage period. No significant difference was observed in the growth of Lactobacillus delbrueckii ssp. bulgaricus between experimental cheeses at the same storage period. However, the growth of Streptococcus thermophilus, Lactobacillus casei, and Lactobacillus acidophilus was significantly affected among experimental cheeses. A significant difference was observed in soluble Ca among experimental cheeses at the same storage period. In general, no significant differences existed in hardness and adhesiveness among experimental cheeses at the same storage period. No significant differences existed in sensory attributes, including creaminess, bitterness, saltiness, sour-acid, and vinegar taste among experimental Akawi cheeses at the same storage period. PMID:22916878

  4. Anisotropy of longitudinal ultrasonic absorption in anharmonic processes of scattering in Ge, Si, InSb, MgO, and KCl cubic crystals: The role of damping of phonon states

    NASA Astrophysics Data System (ADS)

    Kuleyev, I. G.; Kuleyev, I. I.

    2010-07-01

    The relaxation of longitudinal phonons and absorption of ultrasound in cubic crystals with positive (Ge, Si, InSb, MgO) and negative (KCl) anisotropies of the second-order elastic moduli have been investigated. The scattering processes occurring with the participation of three longitudinal phonons (the LLL mechanism) and the processes of scattering of a longitudinal phonon by two transverse thermal phonons (the LTT mechanism) have been considered in terms of the anisotropic-continuum model. The influence of damping of phonon states on the anisotropy of longitudinal ultrasonic absorption has been examined. The specific features of phonon scattering and the influence of anisotropy of the harmonic and anharmonic energies of the cubic crystals on the ultrasonic absorption have been analyzed. In contrast to the previously performed calculations, the influence of cubic anisotropy of the harmonic and anharmonic energies of the phonon system on the relaxation processes has been exactly taken into account in the present study. The results of the calculations have been compared with experimental data.

  5. ESR study of the complexes [ClO, O2] and [BrO, O2] formed by decomposition of ClO - 3 and BrO - 3 in solid KClO4

    NASA Astrophysics Data System (ADS)

    Byberg, J. R.

    1986-04-01

    The ESR spectra of defects arising from photolysis at 214 or 229 nm of ClO-3 and BrO-3 embedded in KClO4 crystals and subsequent radiolysis at 26 K are interpreted in terms of the complexes [XO, O2], X=Cl, Br, formed in the reactions XO-3 ?h? [XO-,O2], [XO-,O2] +(ClO4)-2 ?[XO,O2] +2ClO-4, where (ClO4)-2 represents the mobile holes produced during radiolysis of the host crystal. The main features of the spin Hamiltonian of [XO,O2] correspond to XO(2?) in a crystal field, coupled through an isotropic exchange interaction to O2(3?-g ) to form a spin-doublet ground state, but the observed halogen and 17O hyperfine splittings are considerably smaller than expected for [XO,O2]. Moreover, the splitting of the 2? states of XO inferred from the g tensor is an order of magnitude larger than that observed earlier in a similar system. Both findings indicate an interaction, which splits the degenerate pairs of antibonding ? orbitals on XO and O2 by ˜104 cm-1. In O2 this may lead to near degeneracy of the lowest singlet state with 3?-g, thus allowing a significant singlet-triplet mixing which reduces the net spin density in the complex. The spin Hamiltonian indicates that the axes of XO and O2 are perpendicular. The strong interaction between XO and O2 furthermore suggests a planar T configuration of the complex.

  6. Phosphate-induced metal immobilization in a contaminated site

    Microsoft Academic Search

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

    2003-01-01

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

  7. Melting behavior of fluid inclusions in laboratory-grown halite crystals in the systems NaCl?H 2O, NaCl?KCl?H 2O, NaCl?MgCl 2?H 2O, and NaCl?CaCl 2?H 2O

    NASA Astrophysics Data System (ADS)

    Davis, Daniel W.; Lowenstein, Tim K.; Spencer, Ronald J.

    1990-03-01

    The chemical composition of aqueous fluid inclusions in crystals of halite can be accurately determined from observed melting behaviors of ice, hydrohalite, and sylvite. Some fluid inclusion melting behaviors observed in laboratory-grown halite crystals (systems NaCl?H 2O, NaCl?KCl?H 2O, NaCl?MgCl 2? H 2O, and NaCl?CaCl 2?H 2O) differ from predicted stable equilibrium relations. In the NaCl?H 2O and NaCl?KCl?H 2O systems, observed first melt temperatures are up to 15°C below the equilibrium eutectic temperatures of -21.2° and -22.9°C, respectively. The final melting temperature of ice, in the presence of hydrohalite, and the final melting temperature of hydrohalite are reproducible and match predicted melting temperatures. The limit of detection of sylvite daughter crystals in the NaCl?KCl?H 2O system is approximately 5 wt% (? 1 molal) KCl. Final melting temperatures of sylvite match published equilibrium data to within 0.3°C. In the NaCl?KCl?H 2O system at halite saturation, m KCl can be determined from the final sylvite dissolution temperature or from the final melting temperature of hydrohalite. Fluid inclusions in the NaCl?MgCl 2?H 2O and NaCl?CaCl 2?H 2O systems that form stable salt hydrates (MgCl 2 · 12H 2O and CaCl 2 · 6H 2O) during freezing first melt within 3°C of predicted eutectic temperatures (-37° and -52°C). However, fluid inclusions with MgCl 2 or CaCl 2 may also start melting at temperatures as low as -80°C. Such low first melt temperatures indicate the presence of metastable salt hydrates (presumably MgCl 2 · 8H 2O, MgCl 2 · 6H 2O or CaCl 2 · 4H 2O). The formation of metastable phases during freezing of fluid inclusions can lead to misinterpretation of the chemical composition of fluid inclusions in natural samples. This is especially true for fluid inclusions with first melt temperatures below -37°C which may be erroneously interpreted as being rich in CaCl 2. The final melting of ice in the presence of hydrohalite may vary by more than 15°C in fluid inclusions of different size but identical bulk composition, and occurs at lower temperatures than predicted in fluid inclusions from the NaCl?MgCl 2?H 2O and NaCl?CaCl 2?H 2O systems. However, the final melting temperature of ice in inclusions which fail to nucleate hydrohalite, and the final melting temperature of hydrohalite are reproducible to within ±0.1 ° C and can be used to determine MgCl 2 and CaCl 2 molalities.

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

    PubMed

    Wald, Paul; Pitkänen, Sini; Boddy, Lynne

    2004-12-01

    Creolophus cirrhatus, Hericium erinaceus and H. coralloides were paired against over 20 other wood decay fungi from beech (Fagus sylvatica) covering a range of ecological strategies, on 2% malt agar (MA), 0.5% MA, 0.5% MA adjusted to -1.25 MPa by addition of KCl, 0.5% MA adjusted to pH 4 with KOH/H3PO4 and 0.5% MA under 5% O2/30% CO2 all at 20 degrees C. Creolophus cirrhatus and H. coralloides were also paired against 17 other species in wood, incubated at 20 degrees for 36-38 wk. They were average to good combatants, deadlocking with or replacing over half of the antagonists, H. erinaceus being slightly more combative than the other two species. Outcomes in wood were representative of those in agar. Abiotic conditions altered the outcomes slightly, reduced water potential favouring C. cirrhatus and H. erinaceus. Overall extension rate of C. cirrhatus and H. erinaceus often increased in the presence of antagonists. There was prolific production of fruit bodies in controls and interactions, though notably not under altered gaseous regime. Results are discussed in an ecological context. PMID:15757181

  9. Study of textured ZnO:Al thin film and its optical properties for thin film silicon solar cells

    Microsoft Academic Search

    Wei-Lun Lu; Kuo-Chan Huang; Pin-Kun Hung; Mau-Phon Houng

    The study addresses the optical properties and morphologies of Al-doped ZnO (AZO) films textured by the chemical wet-etching method using three different acid solutions: HCl, HNO3, and H3PO4. An initial AZO film was sputtered on a glass substrate by rf magnetron sputtering. The film surface was then textured by wet-etching using diluted HCl, HNO3, or H3PO4. The average transmittance of

  10. The calorimetric investigation of phosphoric acid– N, N-dimethylformamide system

    Microsoft Academic Search

    J. A Fadeeva; L. E Shmukler; L. P Safonova; A. N Kinchin

    2003-01-01

    Solution and mixing enthalpies for the orthophosphoric acid (H3PO4)–N,N-dimethylformamide (DMF) system were measured over the whole concentration range at 25°C. The standard value of solution enthalpy of phosphoric acid in DMF and the standard transference enthalpy of H3PO4 from water to DMF were calculated. The mixing enthalpy concentration dependence permitted making assumptions on complex formation in the system under investigation.

  11. Physicochemical properties of phosphate ester from palm kernel oil

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    PubMed

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

    2012-01-01

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

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

    E-print Network

    Applebaum, David

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

  14. Volume regulation by Necturus gallbladder: Basolateral KCl exit

    Microsoft Academic Search

    Mikael Larson; Kenneth R. Spring

    1984-01-01

    Summary Swelling of the epithelial cells ofNecturus gallbladder caused by an 18% reduction in the osmolality of the mucosal bath is followed by rapid volume readjustment. This volume regulatory decrease requires Cl and is sensitive to the K and Cl gradients across the basolateral cell membrane. Volume regulatory decrease is not inhibited by amiloride, SITS, ouabain or bicarbonate removal. The

  15. Follow us on twitter: @CSI_KCL Visit our website

    E-print Network

    Kühn, Reimer

    outcomes: a systematic review. Journal of Pain and Symptom Management 2014 [Under Review] #12;Effects review. Journal of Pain and Symptom Management 2014 [Under Review] #12;Effects on processes of care review. Journal of Pain and Symptom Management 2014 [Under Review] #12;Effects on outcomes of care

  16. Combinatorial Mathematicians based in Britain. Abdullah, M. KCL

    E-print Network

    Belrose, Dr. Caroline Vodafone Group Bending, Dr. Thomas D. Middlesex #12;Biggs, Prof. Norman L. LSE Biró. Keith Birkbeck Gillett, Dr. Raphael T. Leicester Gilmour, Prof. S. G. QMUL Glass, Prof. Celia A. City

  17. Quantum Theoretical Study of KCl and LiCl Clusters

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  18. www.kcl.ac.uk/campuslife/campuses REGENT'S PARK

    E-print Network

    Applebaum, David

    and Swindon; the nearest railway station is Swindon. Denmark Hill Campus #12;RIVERTHAMES K in g s Reach 1 2 4 Temple Lane Surrey Street Strand BLACKFRIARS BRIDGE CatherineSt New Bridge Street Strand TEMPLE VictoriaEmbankment BLACKFRIARS WATERLOO BRIDGE Savoy Street WellingtonSt ExeterSt Strand Lancaster Place Farringdon Rd Aldwych

  19. Follow us on twitter: @CSI_KCL Visit our website

    E-print Network

    Kühn, Reimer

    understanding of the sector · To advocate for hospice/SPC services · To guide future models of care, collected over time and at patient level to maximise opportunities to drill down and identify changes over Demographic and clinical data, including patient and family outcomes At individual patient and family level

  20. High-Speed (60 GHz) and Low-Voltage-Driving Electroabsorption Modulator Using Two-Consecutive-Steps Selective-Undercut-Wet-Etching Waveguide

    Microsoft Academic Search

    Tsu-Hsiu Wu; Yi-Jen Chiu; Fang-Zheng Lin

    2008-01-01

    Based on a novel structure of waveguide, a broadband electroabsorption modulator (EAM) with low driving voltage and high extinction ratio has been demonstrated in this letter. The waveguide of InGaAsP-InP p-i-n layer structure is fabricated by two consecutive steps of selective undercut-wet-etching: 1)HCl : H3PO4 on p-InP (p- layer), and 2)H3PO4 : H2O2 : H2O on InGaAsP (active region), showing

  1. Photoelectrochemical application of nanotubular titania photoanode

    Microsoft Academic Search

    Yibing Xie

    2006-01-01

    Titania\\/titanium (TiO2\\/Ti) electrodes with tailored surface structure have been fabricated by galvanostatic–potentiostatic anodization process. Highly ordered titania nanotubes array can be prepared by electrolyzing titanium foil at 20V for 40min in HF–H3PO4 electrolyte. Comparatively, micro-structured and crystallized TiO2 multiporous film can be prepared at 20–40V for 6h in H2SO4–H3PO4–H2O2–HF electrolyte. The morphological characteristics and crystal behaviors of both nanotubular and

  2. New method of treating dilute mineral acids using magnesium–aluminum oxide

    Microsoft Academic Search

    Tomohito Kameda; Fumiko Yabuuchi; Toshiaki Yoshioka; Miho Uchida; Akitsugu Okuwaki

    2003-01-01

    Mineral acids, such as H3PO4, H2SO4, HCl, and HNO3, were treated with magnesium–aluminum oxide (Mg–Al oxide), which behaved as a neutralizer and fixative of anions. Anion removal increased with increasing Mg–Al oxide quantity, time, Mg\\/Al molar ratio, and initial acid concentration. Up to 95% removal of anions was achieved in 0.5N acids using a stoichiometric quantity of Mg0.80Al0.20O1.10 for H3PO4,

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

    Microsoft Academic Search

    A. A. Ahmad; B. H. Hameed

    2010-01-01

    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 (H3PO4) as chemical agent. The effects of three preparation variables activation temperature, activation time

  4. Accelerated Articles Quantitative Analysis of Protein Phosphorylation in

    E-print Network

    Chait, Brian T.

    reported hypothesis-driven multistage MS (HMS-MS) method (Chang, E. J.; Archambault, V.; McLachlin, D. T of the dominant loss of H3PO4 during MS/MS from singly charged phosphopeptide ions produced by matrix-assisted laser desorption/ionization (MALDI) in the ion trap mass spectrometer. In the present work, quantitation

  5. Preparation and dispersion of NiCu composite nanoparticles Yu-Guo Guo,y Li-Jun Wan,* Jian-Ru Gong and Chun-Li Bai*

    E-print Network

    Gong, Jian Ru

    of the sandwich cylinder-shaped Cu­Ni­Cu nano- particles was carried out by using the process shown schemati in a wide range of metals and other materials. The so-prepared particles may be suitable candidates LÀ1 CuCl2 mixed solution. Then, the barrier layer was dissolved in 5% H3PO4 . Finally, a silver film

  6. A Study of the Electrochemical Behavior of Copper in Acid Medium in Presence of Some Organic Amine Compounds

    Microsoft Academic Search

    Salah M. Abd El Hleem; A. M. Ahmed; A. E. El-Naggar

    2010-01-01

    The rate of corrosion of copper metal in presence of methyl amine, dimethyl amine, diethyl amine, triethyl amine, diethanol amine, and triethanol amine determined by measuring the anodic limiting current. The factors used are type of organic amine compounds and its concentration, concentration of H3Po4, viscosity of solution, density, diffusion coefficient, and rate of rotation. It has been found that,

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Studies on the Obtaining Process of Fertilizers Based on Ammonium Phosphates with Addition of Sodium Tetraborate

    Microsoft Academic Search

    A. Magda; C. Muntean; P. Negre; L. Lup; G. Bandur; A. Iovi; L. Coste

    The present paper presents studies about the obtaining process of fertilizers based on ammonium phosphates with boron added as micronutrient. Sodium tetra borate, introduced at various NH3:H3PO4 molar ratio, was used as boron source, in order to obtain thermal stable compounds, with a minimum loss of nutritional elements.

  9. Production of ethanol and furfural from corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has potential for economical production of biofuels and value-added chemicals. The conversion of corn stover to sugars involves pretreatment and enzymatic hydrolysis. We have optimized hydrothermal, dilute H2SO4 and dilute H3PO4 pretreatments of corn stover for enzymatic saccharificati...

  10. Production of cellulose phosphate from oil palm empty fruit bunch: Effect of chemical ratio

    NASA Astrophysics Data System (ADS)

    Rohaizu, R.; Wanrosli, W. D.

    2015-06-01

    Cellulose phosphate was synthesized from oil palm biomass residue that has the potential to represent a considerable added value product for the oil palm biomass utilization. Cellulose phosphate (CP) is prepared viaa phosphorylation process using the H3PO4/P2O5/Et3PO4/hexanol sequence using oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) as the starting material. Various factors affect its synthesis; one of them which is the subject of this investigation is the orthophosphoric acid (H3PO4) to triethylphosphate(Et3PO4) ratio which have the capability to increase the phosphorus content of CP. It is believed that during this reaction, the esterification of the free hydroxyl groups of the cellulose occurred. The H3PO4/Et3PO4 ratios applied were 0.16, 1.00, and 1.84. The effect of the H3PO4/Et3PO4 ratio on phosphorus content, yield, water swelling and molecular structure of CP are discussed.

  11. Observation of Phosphorylation Site-Specific Dissociation of Singly

    E-print Network

    Kim, Myung Soo

    Young Sik Shin,a Jeong Hee Moon,b and Myung Soo Kima a Department of Chemistry, Seoul National-terminus, intense an 97 peaks were observed. These ions were formed by cleavage at phosphorylated residues only/D exchange studies showed that an 97 was formed by H3PO4 loss from an 1 radical cations. The site

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  13. A discrete model for microstructuring and pattern formation in laser driven

    E-print Network

    Harting, Jens

    A discrete model for microstructuring and pattern formation in laser driven etching of metallic surfaces Alejandro Mora, Maria Haase IHR - University of Stuttgart ICP Oberseminar, 13th June 2005 For more chemical Etching Stainless steel samples Etchant : a solution of H3 PO4 or H2 SO4 Ar+ Laser at 514nm

  14. Thermodynamic investigation of the orthophosphoric acid— N, N-dimethylformamide system

    Microsoft Academic Search

    L. P. Safonova; Y. A. Fadeeva; L. E. Shmukler; A. N. Kinchin

    2005-01-01

    The solution and mixing enthalpies of phosphoric acid (H3PO4)–N,N-dimethylformamide (DMF) system over the whole concentration range were measured at a temperature of 25 °C. Conclusions about complex-formation in the system under investigation were drawn. The standard solution enthalpy of phosphoric acid in DMF was calculated.

  15. Polyvinylpyrrolidone and polyethylenimine as inhibitors for the corrosion of a low carbon steel in phosphoric acid

    Microsoft Academic Search

    Y. Jianguo; W. Lin; V. Otieno-Alego; D. P. Schweinsberg

    1995-01-01

    Polarization and weight loss studies showed that both polyvinylpyrrolidonc and polyethylenimine are effective for the inhibition of low carbon steel over a wide concentration range of aqueous phosphoric acid (H3PO4) solutions. Both polymers retard the anodic and cathodic corrosion reactions with emphasis on the former. The results for uninhibited acid confirm the kinetic expression proposed by Mathur and Vasudevan.

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

    PubMed Central

    2014-01-01

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

  17. A titration model for evaluating calcium hydroxide removal techniques

    PubMed Central

    PHILLIPS, Mark; McCLANAHAN, Scott; BOWLES, Walter

    2015-01-01

    Objective Calcium hydroxide (Ca(OH)2) has been used in endodontics as an intracanal medicament due to its antimicrobial effects and its ability to inactivate bacterial endotoxin. The inability to totally remove this intracanal medicament from the root canal system, however, may interfere with the setting of eugenol-based sealers or inhibit bonding of resin to dentin, thus presenting clinical challenges with endodontic treatment. This study used a chemical titration method to measure residual Ca(OH)2 left after different endodontic irrigation methods. Material and Methods Eighty-six human canine roots were prepared for obturation. Thirty teeth were filled with known but different amounts of Ca(OH)2 for 7 days, which were dissolved out and titrated to quantitate the residual Ca(OH)2 recovered from each root to produce a standard curve. Forty-eight of the remaining teeth were filled with equal amounts of Ca(OH)2 followed by gross Ca(OH)2 removal using hand files and randomized treatment of either: 1) Syringe irrigation; 2) Syringe irrigation with use of an apical file; 3) Syringe irrigation with added 30 s of passive ultrasonic irrigation (PUI), or 4) Syringe irrigation with apical file and PUI (n=12/group). Residual Ca(OH)2 was dissolved with glycerin and titrated to measure residual Ca(OH)2 left in the root. Results No method completely removed all residual Ca(OH)2. The addition of 30 s PUI with or without apical file use removed Ca(OH)2 significantly better than irrigation alone. Conclusions This technique allowed quantification of residual Ca(OH)2. The use of PUI (with or without apical file) resulted in significantly lower Ca(OH)2 residue compared to irrigation alone. PMID:25760272

  18. The effects of calcium hydroxide on hydrogen chloride emission characteristics during a simulated densified refuse-derived fuel combustion process.

    PubMed

    Chiang, Kung-Yuh; Jih, Jer-Chyuan; Lin, Kae-Long

    2008-08-30

    This study investigated the effects of different calcium hydroxide (Ca(OH)(2)) addition methods on the potential for hydrogen chloride (HCl) formation in a simulated densified refuse-derived fuel (RDF-5) with single metal combustion system. These experiments were conducted at 850 degrees C with the Ca(OH)(2) spiked in the RDF-5 production or injection in the flue gas treatment system. The results indicated that the potential for HCl formation was decreased significantly by Ca(OH)(2) spiked in the RDF-5 production or injection in the flue gas treatment system. However, the Ca(OH)(2) injection method in the flue gas for HCl emission reduction was better than other method. According to the relationship between the HCl emission and amount of Ca(OH)(2) injected or spiked, it is interesting to find that when the Ca(OH)(2) injected or spiked ranged from 0% to 5%, the potential for HCl formation in the single metal combustion system decreases significantly with increasing Ca(OH)(2) injected or spiked ratio. A corresponding increase in the amount of CaCl(2) partitioned to the fly ash was observed. However, with the ratio of Ca(OH)(2) higher than 5%, the amount of HCl formation showed that no further significant variation occurred with increasing Ca(OH)(2) spiked ratio. PMID:18272287

  19. Chemical characterization of combustion deposits by TOF-SIMS

    NASA Astrophysics Data System (ADS)

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

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kaur, Kamaldip; Mittal, Raj

    2014-12-01

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

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

    PubMed

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

    2010-01-01

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

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

    PubMed

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

    2011-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  4. The Use of Activated Carbon Prepared from Jackfruit (Artocarpus heterophyllus) Peel Waste for Methylene Blue Removal

    Microsoft Academic Search

    Devarly PRAHAS; Yoga KARTIKA; Nani INDRASWATI; Suryadi ISMADJI

    Jackfruit peel waste which has no economic value has been utilized for activated carbon preparation. The preparation of the activated carbon was carried out using chemical activation with phosphoric acid as activating agent. The impregnation ratio was 4:1 (g H3PO4\\/g raw material) and semi carbonization process was conducted at 200oC and followed with carbonization at 550oC. The applicability of this

  5. A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols

    PubMed Central

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

    2014-01-01

    The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin. Objective The objective of the present study was to evaluate the effect of different irrigant protocols on coronal bacterial microleakage of gutta-percha/AH Plus and Resilon/Real Seal Self-etch systems. Material and Methods One hundred ninety pre-molars were used. The teeth were divided into 18 experimental groups according to the irrigation protocols and filling materials used. The protocols used were: distilled water; sodium hypochlorite (NaOCl)+eDTA; NaOCl+H3PO4; NaOCl+eDTA+chlorhexidine (CHX); NaOCl+H3PO4+CHX; CHX+eDTA; CHX+ H3PO4; CHX+eDTA+CHX and CHX+H3PO4+CHX. Gutta-percha/AH Plus or Resilon/Real Seal Se were used as root-filling materials. The coronal microleakage was evaluated for 90 days against Enterococcus faecalis. Data were statistically analyzed using Kaplan-Meier survival test, Kruskal-Wallis and Mann-Whitney tests. Results No significant difference was verified in the groups using chlorhexidine or sodium hypochlorite during the chemo-mechanical preparation followed by eDTA or phosphoric acid for smear layer removal. The same results were found for filling materials. However, the statistical analyses revealed that a final flush with 2% chlorhexidine reduced significantly the coronal microleakage. Conclusion A final flush with 2% chlorhexidine after smear layer removal reduces coronal microleakage of teeth filled with gutta-percha/AH Plus or Resilon/Real Seal SE. PMID:25025557

  6. Microbial fuel cell enables phosphate recovery from digested sewage sludge as struvite

    Microsoft Academic Search

    Fabian Fischer; Christèle Bastian; Manuel Happe; Eric Mabillard; Nicolas Schmidt

    2011-01-01

    Orthophosphate was mobilized from iron phosphate (FePO4) contained in digested sewage sludge by microbial fuel cell power. FePO4 was reduced through electrons and protons obtained from metabolic activity of Escherichia coli. The process yielded up to 82% or 600mg\\/l. Optical emission spectroscopy was used for phosphate dosage. 31P NMR showed a singlet at ?p=3.72ppm indicating that orthophosphate (H3PO4, HPO4-, HPO42-

  7. “Acid” pyrolysis-capillary chromatographic analysis of anionic and nonionic surfactants

    Microsoft Academic Search

    H. L. Lew

    1967-01-01

    A tandem “acid” pyrolysis-capillary chromatographic method for analyzing surfactants has been developed, and its application\\u000a to the more common anionic and nonionic surfactant types investigated. In this method a surfactant is mixed with an acid,\\u000a such as P2O5 or H3PO4, and dropped into a pyrolyzer attached to a capillary gas chromatograph. The resulting volatile pyrolyzate is carried into\\u000a the chromatograph

  8. High Precision 13C\\/12C Measurement of Dissolved Carbon Using a Transportable Cavity Ring-Down Spectrophotometer System

    Microsoft Academic Search

    N. Saad; E. Crosson

    2009-01-01

    We report here on the measurement of high precision delta13C from total inorganic carbon (TIC) and dissolved organic carbon (DOC) using a sample preparation system coupled to a small footprint Wavelength- Scanned Cavity Ring-Down Spectrometer (WS-CRDS). This system is capable of applying a 5% H3PO4 solution or a sodium persulfate oxidation process to a water sample in an exetainer vial,

  9. Agave sisalana, a biosorbent for the adsorption of Reactive Red 120 from aqueous solution

    Microsoft Academic Search

    Venkateshwarapuram Rengaswami Giri Dev; Jayarama Reddy Venugopal; Thamdiannan Senthil Kumar; Lima Rose Miranda; Seeram Ramakrishna

    2010-01-01

    The textile industry is one of the largest producers of dye effluent. Treatment of these effluents has to be cost effective hence a number of precursors have been studied as a viable alternative adsorbent. Sisal fibre was converted to activated carbon by chemical methods. Sisal fibre was activated with different activating agents such as H3PO4, HCl, HNO3, NaOH and KOH.

  10. Effect of sulfuric and phosphoric acid pretreatments on enzymatic hydrolysis of corn stover

    Microsoft Academic Search

    Byung-Hwan Um; M. Nazmul Karim; Linda L. Henk

    2003-01-01

    The pretreatment of corn stover with H2SO4 and H3PO4 was investigated. Pretreatments were carried out from 30 to 120 min in a batch reactor at 121°C, with acid concentrations\\u000a ranging from 0 to 2% (w\\/v) at a solid concentration of 5% (w\\/v). Pretreated corn stover was washed with distilled water until\\u000a the filtrate was adjusted to pH 7.0, followed by

  11. Applicability of Activated Carbon to Treatment of Waste Containing Iodine-Labeled Compounds

    Microsoft Academic Search

    H. M. H. Gad; N. R. A. El-Mouhty; H. F. Aly

    2009-01-01

    A timber industry waste was transformed to activated carbon by a one-step chemical activation process using H3PO4 (H). The used activated carbon (SDH) was characterized by N2 adsorption, FTIR, density, pH, point of zero charge pHpzc, moisture and ash content. Methylene blue (MB) and the iodine number were calculated by adsorption from the solution. The applicability of the different activated

  12. Preparation and adsorption performances of mesopore-enriched bamboo activated carbon

    Microsoft Academic Search

    Yuxin Wang; Congmin Liu; Yaping Zhou

    2008-01-01

    Activated carbon with high specific surface area and considerable mesopores was prepared from bamboo scraps by phosphoric\\u000a acid activation. The effect of activation conditions was studied. Under the conditions of impregnating bamboo with 80% H3PO4 at 80°C for 9 days and activation at 500°C for 4 h, the prepared activated carbon had the highest mesopore volume of 0.67\\u000a cm3\\/g, a

  13. Granular activated carbons from nutshells for the uptake of metals and organic compounds

    Microsoft Academic Search

    C. A. Toles; W. E. Marshall; M. M. Johns

    1997-01-01

    Almond and pecan shells were chosen as hard, lignocellulosic precursors for the production of granular activated carbons (GACs) in order to create carbons for the adsorption of both organic compounds and metals. They were activated either chemically, with H3PO4, or physically, with CO2, under a variety of conditions. Following activation, a portion of the GACs were oxidized with air.The acid-activated

  14. Influence of different chemical reagents on the preparation of activated carbons from bituminous coal

    Microsoft Academic Search

    Li-Yeh Hsu; Hsisheng Teng

    2000-01-01

    Activated carbons were prepared by chemical activation from bituminous coal with three chemical reagents, ZnCl2, H3PO4 and KOH. The activation consisted of impregnation of a reagent followed by carbonization in nitrogen at various temperatures. A thermogravimetric study showed that these reagents were capable of suppressing the evolution of tarry substances during carbonization. Because of carbon oxidation and gasification mechanisms, activation

  15. Preliminary Surface Analysis of Etched, Bleached, and Normal Bovine Enamel

    Microsoft Academic Search

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

    1990-01-01

    X-ray photoelectron spectroscopic (XPS) and secondary ion-mass spectroscopic (SIMS) analyses were performed on unground un-pumiced, unground pumiced, and ground labial enamel surfaces of young bovine incisors exposed to four different treatments: (1) immersion in 35% H2O2 for 60 min; (2) immersion in 37% H 3PO4 for 60 s; (3) immersion in 35% H2O2 for 60 min, in distilled water for

  16. Effect of an acidic treatment on the chemical and charge properties of a nanofiltration membrane

    Microsoft Academic Search

    R. Navarro; M. P. González; I. Saucedo; M. Avila; P. Prádanos; F. Martínez; A. Martín; A. Hernández

    2008-01-01

    In order to improve the performance of a nanofiltration membrane (DS5 DL from Osmonics®) several pre-treatments have been tested. Specifically, the membrane has been immersed, for different times, in an aqueous solution of HF or H3PO4, or of a mixture of both these acids. The chemical and charge properties of the membranes, both pre-treated and untreated, have been studied.The chemical

  17. Effect of doping of organic and inorganic acids on polyaniline\\/Mn 3O 4 composite for NTC and conductivity behaviour

    Microsoft Academic Search

    M. L. Singla; Sajeela Awasthi; Alok Srivastava; D. V. S. Jain

    2007-01-01

    The paper deals with the study of TCR and conductivity behaviour of the PANI\\/Mn3O4 composite in its emeraldine salt state doped with different acids like H3PO4, H2SO4, HClO4, CH3COOH and CH2CHCOOH. The conductivity results have also been compared with pure emeraldine salt doped with same acid. The characterisation of each composite sample and emeraldine salt was done using XRD, FT-IR,

  18. Comparison of the morphology and reactivity in HDS of CoMo\\/HMS, CoMo\\/P\\/HMS and CoMo\\/SBA15 catalysts

    Microsoft Academic Search

    R. Nava; B. Pawelec; J. Morales; R. A. Ortega; J. L. G. Fierro

    2009-01-01

    Mesoporous HMS and SBA-15 materials were synthesized using dodecylamine and pluronic triblock copolymer as surfactants, respectively. The P-modified HMS material (P\\/HMS) was prepared by incipient wetness impregnation of calcined HMS substrate with aqueous solutions of H3PO4. The influence of support (HMS, P\\/HMS, SBA-15) and metal loading on both bulk and surface structures of calcined and sulfided CoMo catalysts were studied

  19. Thermodynamic Study of Corrosion and Inhibitor Adsorption Processes onto C38 Steel\\/piperazines\\/phosphoric Acid Systems

    Microsoft Academic Search

    A. Ousslim; A. Ouniti; K. Bekkouch; A. Elidrissi; B. Hammouti

    2009-01-01

    This paper describes the inhibition effect of 1-benzyl piperazine (P1) and bis(1-benzyl piperazine) thiuram disulfide (P2) towards the corrosion of C38 steel in 5.5 M H3PO4 solution by potentiodynamic polarization and weight loss methods. The influence of inhibitor concentration and temperature on inhibitory behavior of P2 were investigated. The inhibition efficiency (IE) was found to be dependent on the type

  20. Direct synthesis of H 2O 2 from H 2 and O 2 over Pd\\/H-beta catalyst in an aqueous acidic medium: Influence of halide ions present in the catalyst or reaction medium on H 2O 2 formation

    Microsoft Academic Search

    Chanchal Samanta; Vasant R. Choudhary

    2007-01-01

    The influence of different halide ions present in the catalyst or reaction medium on the performance of Pd\\/H-beta catalyst in the direct H2O2 synthesis in an aqueous acidic (0.03M H3PO4) reaction medium at 27°C and atmospheric pressure has been thoroughly investigated. The results showed a strong influence of both the bulk Pd oxidation state in the catalyst and the halide

  1. Morphology of porous n-GaP anodically formed in different mineral acids

    Microsoft Academic Search

    J. Wloka; P. Schmuki

    2006-01-01

    n-type GaP(100) was anodized in H2SO4, HF, HCl, HBr, HI, HNO3 and H3PO4 in order to obtain porous structures. Remarkable differences in the morphology were found when anodisation was carried out under comparable electrochemical conditions. Etching in HF led to a statistically porous structure, but no evidence for higher ordering was obtained. Etching in HCl solutions caused a localized attack

  2. Effect of surface chemistry on gas-phase adsorption by activated carbon prepared from oil-palm stone with preimpregnation

    Microsoft Academic Search

    Jia Guo; Aik Chong Lua

    1999-01-01

    Effects of surface chemistry (acidity or basicity) on gas-phase adsorption (NO2 or NH3) by activated carbons prepared from oil-palm stones pre-impregnated with various solutions (ZnCl2, H3PO4 and KOH) were studied in this paper. Textural and chemical characterizations of these activated carbons were carried out. High solid density and hardness, fairly high BET surface area and predominant microporosity (as shown in

  3. Characterization of etching procedure in preparation of CdTe solar cells

    Microsoft Academic Search

    Juha Sarlund; Mikko Ritala; Markku Leskelä; Eija Siponmaa; Riitta Zilliacus

    1996-01-01

    An etching procedure for forming a low resistance contact to polycrystalline CdTe thin films in CdS\\/CdTe solar cells was studied. The etching solution used was a mixture of HNO3, H3PO4 and H2O. X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS) and electric measurements revealed that the etching results in a formation of crystalline tellurium on the film surface, thereby increasing

  4. A Modified Method for Saline Lake Calcite Isotope Analysis: Application to a Study of Climate Change over 200,000 Years in Death Valley, California

    Microsoft Academic Search

    W. Yang; T. K. Lowenstein; R. H. Krouse; R. J. Spencer; T. Ku

    2004-01-01

    The standard method of oxygen and carbon isotope analyses for carbonate minerals was first reported by McCrea (1950). Carbonates are converted to CO2 by the reaction of carbonates with 100% phosphoric acid at temperatures between 25 and 95° C for C- and O-isotope analyses: 3CaCO3 + 2H3PO4 = 3CO2 + 3H2O + Ca3(PO4)2 The reaction time for this method can

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

    Microsoft Academic Search

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

    2005-01-01

    Phosphoric acid (H3PO4) 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

  6. Comparison of spectrophotometric and HPLC methods for determination of lipid peroxidation products in rat brain tissues

    Microsoft Academic Search

    M. ?urfinová; M. Brechtlová; B. Líška; Ž. Barošková

    2007-01-01

    Two methods for determination of lipid peroxidation (LPX) products in rat brain homogenates were compared. The thiobarbituric\\u000a acid (TBA) test and HPLC assay for analysis of malondialdehyde (MDA) were applied. Rat brain homogenate dissolved in tris(hydroxymethyl)aminomethane\\u000a hydrochloride (Tris-HCl) was mixed with TBA and H3PO4 and heated at 100°C to form colored complex that was extracted into butanol. No significant differences

  7. Double reverse flotation of a very low grade sedimentary phosphate rock, rich in carbonate and silicate

    Microsoft Academic Search

    M. Mohammadkhani; M. Noaparast; S. Z. Shafaei; A. Amini; E. Amini; H. Abdollahi

    2011-01-01

    In this study, reverse flotation was applied to recover phosphate from a very low grade (5.01% of P2O5) sedimentary ore. Sodium silicate, starch, tannic acid, aluminum sulfate, (Na,K)Tartarat, sodium tripolyphosphate, H3PO4, and H2SO4 were used as phosphate mineral depressants in acidic and alkaline conditions. Oleic acid and Armac-T were added as carbonate and silicate collectors respectively, while pine oil was

  8. Deformation of nonfired refractories based on phosphate binders. 6. Deformation under heating and creep in corundum composites

    Microsoft Academic Search

    V. S. Bakunov; U. Sh. Shayakhmetov

    2007-01-01

    The results of studying heating deformation and creep are described for two systems: electrocorundum — ?-Al2O3 — phosphate binder and electrocorundum — pyrophyllite — phosphate binder. It is shown that composites with H3PO4 experience less deformation than composites with the alumochromium-phosphate binder, whereas using pyrophyllite instead of\\u000a aluminum oxide increases creep deformation due to the presence of the liquid phase

  9. Proximal direct composite restorations and chairside CAD\\/CAM inlays: Marginal adaptation of a two-step self-etch adhesive with and without selective enamel conditioning

    Microsoft Academic Search

    T. Bortolotto; I. Onisor; I. Krejci

    2007-01-01

    The aim of this study was to evaluate the marginal adaptation of CEREC ceramic inlays, CEREC composite inlays and direct composite\\u000a restorations in unbeveled proximal slot cavities under artificial aging conditions. Two groups of each restoration type were\\u000a prepared (n?=?6), one group with a self-etch adhesive, the other group with H3PO4 enamel etching before the self-etch adhesive application. Replicas were

  10. The improvement of free-radical scavenging capacity of the phosphate medium electrosynthesized polyaniline

    Microsoft Academic Search

    Ali Parsa; Sulaiman Ab Ghani

    2009-01-01

    The oxidative polymerization of aniline on composite 2B pencil graphite was accomplished in phosphoric acid (H3PO4) containing 0.06M calcium phosphate (Ca3(PO4)2). The shifting of three pairs of redox peaks by 250mV to the negative direction has increased antioxidant capacity of polyaniline (PAni). This was realised through reaction with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical in methanol. The phosphate medium prepared PAni was a

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

    Microsoft Academic Search

    Xianghong Li; Shuduan Deng; Hui Fu; Guannan Mu

    2010-01-01

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

  12. Temperature dependence on addition of urea and its related compounds on formation of neodymium condensed phosphates

    Microsoft Academic Search

    Hiroaki Onoda; Atsushi Takenaka; Kazuo Kojima; Hiroyuki Nariai

    2005-01-01

    Urea (CO(NH2)2) and its related compounds (biuret: NH(CONH2)2 and cyanuric acid: (CONH)3) were mixed with phosphoric acid (H3PO4) and neodymium oxide (Nd2O3). The thermal behavior of these dried mixtures was estimated by differential thermal analyses, X-ray diffraction, and Fourier-transform infrared spectroscopy. Furthermore, specific surface area of phosphates was calculated by BET method using nitrogen adsorption. The addition of urea prevented

  13. Adsorption properties of barbiturates as green corrosion inhibitors on mild steel in phosphoric acid

    Microsoft Academic Search

    Muzaffer Özcan; Ramazan Solmaz; Gülfeza Karda?; ?lyas Dehri

    2008-01-01

    Barbituric acid (BA), 5,5-dietylbarbituric acid sodium salt (DEBA) and thiobarbituric acid (TBA) were investigated as corrosion inhibitors for mild steel in 1M H3PO4 solution at 25±1°C using AC impedance spectroscopy, linear polarization resistance (LPR) measurement and polarization curves measurement techniques. AC impedance results were interpreted using an equivalent circuit in which a constant phase element (CPE) was used in place

  14. COMPARATIVE STUDIES OF SOME HETEROCYCLIC COMPOUNDS AS CORROSION INHIBITORS OF COPPER IN PHOSPHORIC ACID MEDIA

    Microsoft Academic Search

    Mohsen Lashgari; Mohammad-Reza Arshadi; Masoume Biglar

    2010-01-01

    Corrosion inhibition properties of some heterocyclic compounds (3-mercapto 1,2,4 triazole, benzotriazole, thiophene, and tetra hydro-thiophene) in Cu\\/H3PO4 medium were investigated theoretically and experimentally via cluster\\/polarized continuum and gravimetric approaches. Second-order Møller-Plesset perturbation and density functional theories were applied, and the electronic chemical potential, molecular softness, and extent of charge transfer were determined for inhibitor molecules at the metal\\/solution interface. Good

  15. TiO2 nanotubes: H+insertion and strong electrochromic effects

    Microsoft Academic Search

    Andrei Ghicov; Hiroaki Tsuchiya; Robert Hahn; Jan M. Macak; Andres G. Muñoz; Patrik Schmuki

    2006-01-01

    The present work studies H+ intercalation and electrochromic effects on anodic TiO2 nanotube layers. The nanotube layers were fabricated by anodization of titanium in 1 M (H3PO4) + 1 M (NaOH) + 0.5 wt% HF electrolyte at 20 V, this results in nanotubular layers with a thickness of 1 ± 0.1 ?m with individual tube diameter of 100 ± 10

  16. The effect of Ti-colloid surface conditioning on the phosphating of 7075-T6 aluminium alloy

    Microsoft Academic Search

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

    1996-01-01

    7075-T6 aluminium alloys panels were surface conditioned in a titanium colloid suspension, under a variety of different conditions, and subsequently these samples were immersed in a ZnO + H3PO4 coating mixture, and the phosphate coating layers characterized. Morphologies observed by scanning electron microscopy (SEM) reveal that the coating layer consists of two phases, namely an amorphous phase, which is directly

  17. Specific features of the gas-chromatographic determination of the reaction products in the catalytic decomposition of hydrogen sulfide

    Microsoft Academic Search

    V. I. Zheivot; V. N. Krivoruchko; A. S. Medvedev; O. V. Voroshina

    2006-01-01

    Specific features of the determination of hydrogen sulfide in the presence of hydrogen were studied by gas chromatography\\u000a with the use of a thermal conductivity detector and argon as the carrier gas. A chromatographic column with HayeSep A modified\\u000a with 10 wt % H3PO4 was proposed for the simultaneous determination of both components. It was demonstrated that the elution curve

  18. Preparation and characterization of polyaniline\\/manganese dioxide composites via oxidative polymerization: Effect of acids

    Microsoft Academic Search

    Ali H. Gemeay; Ikhlas A. Mansour; Rehab G. El-Sharkawy; Ahmed B. Zaki

    2005-01-01

    Polyaniline\\/manganese dioxide (PANI\\/MnO2) composites have been chemically prepared by oxidative polymerization of aniline in acidic medium containing MnO2 as an oxidant. The acids used were; H2SO4, HNO3, HCl, and H3PO4 The prepared composites were characterized by SEM, elemental analysis, FT-IR, XRD, TGA, and magnetic susceptibility. XRD measurements of the composites revealed that the crystal structure of incorporated MnO2 undergone a

  19. Applications of polyaniline doubly doped with p-toluene sulphonic acid and dichloroacetic acid as microwave absorbing and shielding materials

    Microsoft Academic Search

    Sook-Wai Phang; Tetsuo Hino; M. H. Abdullah; Noriyuki Kuramoto

    2007-01-01

    Doped-polyanilines (PAnis) were prepared at 0°C using different synthesized parameters such as different ratio of dopants like p-toluene sulphonic acid (pTSA) and dichloroacetic acid (DCA), oxidant (ammonium peroxydisulfate, APS) and various kind of solvents (H2O, HCl aqueous and H3PO4 aqueous). The doped-PAnis were then characterized by UV–vis, FTIR and thermogravimetric analysis. Generally, it is important to control the synthesized parameters

  20. Formation of titanium phosphate composites during phosphoric acid decomposition of natural sphene

    NASA Astrophysics Data System (ADS)

    Maslova, Marina V.; Rusanova, Daniela; Naydenov, Valeri; Antzutkin, Oleg N.; Gerasimova, Lidia G.

    2008-12-01

    Decomposition of mineral sphene, CaTiOSiO 4, by H 3PO 4 is investigated in detail. During the dissolution process, simultaneous calcium leaching and formation of titanium phosphate (TiP) take place. The main product of decomposition is a solid titanium phosphate-silica composite. The XRD, solid-sate NMR, IR, TGA, SEM and BET data were used to identify and characterize the composite as a mixture of crystalline Ti(HPO 4) 2·H 2O and silica. When 80% phosphoric acid is used the decomposition degree is higher than 98% and calcium is completely transferred into the liquid phase. Formation of Ti(HPO 4) 2·H 2O proceeds via formation of meta-stable titanium phosphate phases, Ti(H 2PO 4)(PO 4)·2H 2O and Ti(H 2PO 4)(PO 4). The sorption affinities of TiP composites were examined in relation to caesium and strontium ions. A decrease of H 3PO 4 concentration leads to formation of composites with greater sorption properties. The maximum sorption capacity of TiP is observed when 60% H 3PO 4 is used in sphene decomposition. The work demonstrates a valuable option within the Ti(HPO 4) 2·H 2O-SiO 2 composite synthesis scheme, to use phosphoric acid flows for isolation of CaHPO 4·2H 2O fertilizer.

  1. Electrode behavior of hydrogen reduction in LiCl-KCl melt: Voltammetric analysis

    SciTech Connect

    Ito, Hiroshi; Hasegawa, Yasuo

    2000-01-01

    Hydrogen reduction in molten alkali halide is an important process for the development of thermally regenerative fuel cells using hydrogen and lithium. Hydrogen reduction in LiCl-KCI eutectic melt was studied by the potential-sweep method with Ni, Fe, Co, and Cu electrodes. A reaction model, which considers not only a surface redox process but also the behavior of absorbed hydrogen in the electrode, is proposed. Based on this model, I-E curves are numerically calculated and fitted with experimental voltammograms. A good agreement is obtained between calculated and experimental data in the reversible region, and the validity of this model is demonstrated for Ni, Fe, and Cu electrodes. The Henry's constant for hydrogen in the melt and the diffusion constant were determined from the calculations as follows: {kappa}{sub H} = 5.68 x 10{sup {minus}12} mol/cm{sup 3} Pa, D{sub H{sub 2}} = 3.18 x 10{sup {minus}5} cm{sup 2}/s at 723 K.

  2. Dislocation structure of kcl crystals grown with vibration of the melt

    Microsoft Academic Search

    G. M. Ikonnikova; S. A. Bichurina

    1967-01-01

    The amplitude at all frequencies was 0.04 mm. Three crystals were grown at each frequency, with seeds of dislocation density D = 6 × 104 cm-2. Figure 1 shows the frequency dependence of the final D. Each point in Figs. 1 and 2 is the mean from 50 measurements (50 fields of view). At all frequencies except 180 Hz, D

  3. Acoustic phonon absorption and dispersion in hydroxyl-doped KCl crystals at low temperatures

    E-print Network

    Boyer, Edmond

    contenant plus de 200 ppm de OH-, on observe un pic d'atténuation vers 20 K et une augmentation importante 1 to 50 K. For samples with OH- content higher than 200 ppm, two features dominate the temperature. Introduction. Several independent studies of OH - doped KCI crystals [1-3] have given evidence of an excess

  4. Size effect on the lattice parameter of KCl during mechanical milling

    E-print Network

    Srivastava, Kumar Vaibhav

    . Nanoparticles of CeO2, TiO2, BaTiO3 and SrTiO3 have been studied extensively to investigate this effect [1 et al. [1,2] proposed that lattice expansion in CeO2 nanocrystals is due to the reduction in electro

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

    PubMed Central

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

    2009-01-01

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

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

    SciTech Connect

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

    2012-10-01

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

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

    E-print Network

    Applebaum, David

    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

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

    E-print Network

    Miller, James Edward

    1966-01-01

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

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

    Microsoft Academic Search

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

    2001-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2001-10-01

    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.

  11. GM Media-Sept 21, 2007 PBS, NH4Cl and KCl

    E-print Network

    .99 Vitamins 100 times concentrated stock solution Ingredient Concentration (g/L) biotin 0.2 folic acid 0.2 pyridoxine HCl 1 riboflavin 0.5 thiamin 0.5 nicotinic acid 0.5 pantothenic acid 0.5 B-12 0.01 p-aminobenzoic acid 0.5 thioctic acid 0.5 Diluted Vitamines (the one that should be used inside MFC) To have Final

  12. Rotational dynamics and velocity segregation in plastic KClO4 : a molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Affouard, F.; Depondt, Ph.

    The individual and two-molecule rotational dynamics of ClO ions are studied via a molecular dynamics simulation of a potassium perchlorate crystal in the orientationally disordered phase. In order to overcome the difficulty of dealing with orientational variables, symmetry adapted rotator functions are used. The rotational matrix makes it possible to compute instantaneous rotational velocities and axes. Finally, an effective rotational angle is introduced also. The results obtained with these tools are consistent. The rotational motion is diffusive, but the relative orientations of two neighbouring molecules last longer than that of a single molecule, showing coupled motion. Molecules which are far from the most probable orientations have greater rotational velocity. A tentative interpretation is proposed.

  13. Exposure damage mechanisms for KCl windows in high power laser systems

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  14. K-Cl transport systems in rabbit renal basolateral membrane vesicles

    Microsoft Academic Search

    J. Eveloff; D. G. Warnock

    1987-01-01

    The transport pathways for chloride in basolateral membrane vesicles from the rabbit renal cortex were investigated. ³⁶Cl uptake was stimulated by the presence of potassium in the uptake media compared with sodium of N-methyl-D-glucamine. In addition, potassium (⁸⁶Rb) uptake was stimulated more by chloride than by nitrate or gluconate. Neither of these processes was further stimulated by potassium gradients plus

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

    PubMed

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

    2002-12-15

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

  16. Assessment of the Antibacterial Activity of Calcium Hydroxide Combined with Chlorhexidine Paste and Other Intracanal Medications against Bacterial Pathogens

    PubMed Central

    de Magalhães Silveira, Cláudia Fernandes; Cunha, Rodrigo Sanches; Fontana, Carlos Eduardo; de Martin, Alexandre Sigrist; de Almeida Gomes, Brenda Paula Figueiredo; Motta, Rogério Heládio Lopes; da Silveira Bueno, Carlos Eduardo

    2011-01-01

    Objectives: The purpose of this study was to assess the in vitro antibacterial activity of four formulations of calcium hydroxide [Ca(OH)2] pastes against Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus mutans. Methods: A broth dilution test was performed, and the lengths of time for different pastes to kill the microbial cells were recorded and statistically analyzed. The following medications were assessed: Group I – Ca(OH)2 + 2.0% chlorhexidine (CHX) gel; Group II – Ca(OH)2 + camphorated paramonochlorophenol (CMCP) and propylene glycol; Group III – Ca(OH)2 + propylene glycol; Group IV – Ca(OH)2 + saline. Results: The results showed that E. faecalis was the most resistant microorganism. Groups II and III eliminated all the microbial cells in 15 seconds. Group I took 45 seconds to eliminate E. faecalis. Conclusions: Under the conditions of this study, it was concluded that all the intracanal medications tested showed antibacterial activity. However, the association of Ca(OH)2 and PMCC or Ca(OH)2 and propylene glycol showed a better performance, since Groups II and III took a shorter length of time than the other groups to eliminate S. aureus and E. faecalis. PMID:21311611

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

    Microsoft Academic Search

    Y. Jung; M. Han; S. Lee

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

  18. 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

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

    2003-01-01

    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

  19. Calcium oxide as a solid base catalyst for transesterification of soybean oil and its application to biodiesel production

    Microsoft Academic Search

    Masato Kouzu; Takekazu Kasuno; Masahiko Tajika; Yoshikazu Sugimoto; Shinya Yamanaka; Jusuke Hidaka

    2008-01-01

    In order to study solid base catalyst for biodiesel production with environmental benignity, transesterification of edible soybean oil with refluxing methanol was carried out in the presence of calcium oxide (CaO), -hydroxide (Ca(OH)2), or -carbonate (CaCO3). At 1h of reaction time, yield of FAME was 93% for CaO, 12% for Ca(OH)2, and 0% for CaCO3. Under the same reacting condition,

  20. Proliferation of rat molar pulp cells after direct pulp capping with dentine adhesive and calcium hydroxide

    Microsoft Academic Search

    Till Dammaschke; Udo Stratmann; Rudolf-Josef Fischer; Darius Sagheri; Edgar Schäfer

    2011-01-01

    The aim was to evaluate the proliferation of pulp cells 1, 3 and 7 days after direct pulp capping with the dentine adhesive\\u000a Gluma Comfort Bond (GCB) and to compare it with calcium hydroxide (Ca(OH)2). An occlusal cavity was prepared in 72 molar teeth of 36 Wistar rats. Then GCB or Ca(OH)2 was placed on the exposed pulp. All cavities were

  1. Thermochemical energy storage for a lunar base

    Microsoft Academic Search

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

    1992-01-01

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

  2. Portlandite crystal: Bulk, bilayer, and monolayer structures

    NASA Astrophysics Data System (ADS)

    Aierken, Y.; Sahin, H.; Iyikanat, F.; Horzum, S.; Suslu, A.; Chen, B.; Senger, R. T.; Tongay, S.; Peeters, F. M.

    2015-06-01

    Ca(OH)2 crystals, well known as portlandite, are grown in layered form, and we found that they can be exfoliated on different substrates. We performed first principles calculations to investigate the structural, electronic, vibrational, and mechanical properties of bulk, bilayer, and monolayer structures of this material. Different from other lamellar structures such as graphite and transition-metal dichalcogenides, intralayer bonding in Ca(OH)2 is mainly ionic, while the interlayer interaction remains a weak dispersion-type force. Unlike well-known transition-metal dichalcogenides that exhibit an indirect-to-direct band gap crossover when going from bulk to a single layer, Ca(OH)2 is a direct band gap semiconductor independent of the number layers. The in-plane Young's modulus and the in-plane shear modulus of monolayer Ca(OH)2 are predicted to be quite low while the in-plane Poisson ratio is larger in comparison to those in the monolayer of ionic crystal BN. We measured the Raman spectrum of bulk Ca(OH)2 and identified the high-frequency OH stretching mode A1 g at 3620 cm-1 . In this study, bilayer and monolayer portlandite [Ca(OH)2 ] are predicted to be stable and their characteristics are analyzed in detail. Our results can guide further research on ultrathin hydroxites.

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

    PubMed

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    PubMed

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

    2006-01-01

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

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

    PubMed

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

    2015-07-01

    Collision-induced dissociation (CID) remains the predominant mass spectrometry-based method for identifying phosphorylation sites in complex mixtures. Unfortunately, the gas-phase reactivity of phosphoester bonds results in MS/MS spectra dominated by phosphoric acid (H3PO4) neutral loss events, suppressing informative peptide backbone cleavages. To understand the major drivers of H3PO4 neutral loss, we performed robust nonparametric statistical analysis of local and distal sequence effects on the magnitude and variability of neutral loss, using a collection of over 35,000 unique phosphopeptide MS/MS spectra. In contrast to peptide amide dissociation pathways, which are strongly influenced by adjacent amino acid side chains, we find that neutral loss of H3PO4 is affected by both proximal and distal sites, most notably basic residues and the peptide N-terminal primary amine. Previous studies have suggested that protonated basic residues catalyze neutral loss through direct interactions with the phosphate. In contrast, we find that nearby basic groups decrease neutral loss regardless of mobility class, an effect only seen by stratifying spectra by charge-mobility. The most inhibitory bases are those immediately N-terminal to the phosphate, presumably because of steric hindrances in catalyzing neutral loss. Further evidence of steric effects is shown by the presence of proline, which can dramatically reduce the presence of neutral loss when between the phosphate and a possible charge donor. In mobile proton spectra, the N-terminus is the strongest predictor of high neutral loss, with proximity to the N-terminus essential for peptides to exhibit the highest levels of neutral loss. Graphical Abstract ?. PMID:25851653

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

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

    PubMed Central

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

    2014-01-01

    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

  9. Defect selective etching of GaAsyP1-y photovoltaic materials

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  10. Low temperature synthesis of hydroxyapatite nano-rods by a modified sol–gel technique

    Microsoft Academic Search

    Sushma Jadalannagari; Sandeep More; Meenal Kowshik; Sutapa Roy Ramanan

    2011-01-01

    Hydroxyapatite (HAp) nano-rods were successfully synthesized by a modified sol–gel method using a solution of CaCl2·2H2O in water, along with a solution of H3PO4 in triethylamine and NH4OH as starting materials. The Ca\\/P molar ratio was maintained at 1.67. The sol obtained was dried in an oven for 2days at 100°C after being dialyzed for 12h. Pellets were made from

  11. Inorganic-based sol–gel synthesis of nano-structured LiFePO 4 \\/C composite materials for lithium ion batteries

    Microsoft Academic Search

    Jun Ma; Baohua Li; Hongda Du; Chengjun Xu; Feiyu Kang

    An inorganic and non-toxic compounds combination of FeCl2·4H2O, Li2CO3 and H3PO4 was chosen to synthesize homogeneous nano-structured LiFePO4\\/C composite material via a simplified sol–gel route. The dependency of the physicochemical properties and the corresponding\\u000a electrochemical responses on the residual carbon content were investigated in details. Rietveld refinement of X-ray diffraction\\u000a measurement and X-ray photoelectron spectroscopy analysis confirmed the feasibility of

  12. Synthesis of hierarchical macro\\/mesoporous dicalcium phosphate monolith via epoxide-mediated sol–gel reaction from ionic precursors

    Microsoft Academic Search

    Yasuaki Tokudome; Akira Miyasaka; Kazuki Nakanishi; Teiichi Hanada

    2011-01-01

    Starting from calcium chloride dihydrate (CaCl2·2H2O), phosphoric acid (H3PO4), and poly(acrylic acid) (PAA) dissolved in a mixture of water and methanol (MeOH), dicalcium phosphate anhydrous (DCPA,\\u000a CaHPO4) monoliths with co-continuous macropores and mesopores have been synthesized by the addition of propylene oxide. Macropores\\u000a are formed as a result of phase separation, while mesopores as interstices between primary particles with the

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

    E-print Network

    Garmestani, Hamid

    Acetic Acid (H3COOH): GaAs; Pb; Ti Hydrochloric Acid (HCl): Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In; Fe; Pb; Ni; NiO, Ni2O3; Sn; SnO2; Ti; Zn Hydrofluoric Acid (HF): GaAs; Ni; SiO2; Ti Nitric Acid (HNO3): C; Cu; GaAs; In; Fe; Pb; Ni; Ag; Pd; Pt; Sn; Ti; Zn; ZnO Phosphoric Acid (H3PO4): Al; Cu; GaAs; Ga

  14. Effect of pH value on particle morphology and electrochemical properties of LiFePO 4 by hydrothermal method

    Microsoft Academic Search

    Qingzhu Song; Xiuqin Ou; Li Wang; Guangchuan Liang; Zuorui Wang

    2011-01-01

    Lithium iron phosphate was prepared by hydrothermal synthesis using LiOH·H2O, FeSO4·7H2O and H3PO4 as raw materials. The effects of pH value of reaction solution on particle morphology and electrochemical property were investigated. The pH value of the reaction solution was adjusted in the range of 2.5–8.8 by dilute sulfuric acid and ammonia water. The samples were characterized by field-emission scanning

  15. Effect of Fe(III) impurity on the electrochemical performance of LiFePO 4 prepared by hydrothermal process

    Microsoft Academic Search

    XiuQin Ou; ShengZhao Xu; GuangChuan Liang; Li Wang; Xia Zhao

    2009-01-01

    Lithium iron phosphate (LiFePO4) was synthesized from LiOH, FeSO4 and H3PO4 by a hydrothermal process at 180°C. The samples were characterized by X-ray diffraction, scanning electron microscopy and\\u000a chemical analysis. Electrochemical performance of the samples was tested in terms of charge-discharge capacity and cycling\\u000a behavior. The results indicated that Fe(III) impurity had obviously effect on the electrochemical properties of LiFePO4,

  16. Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors.

    PubMed

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

    2014-08-01

    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

  17. Influence of addition of urea and its related compounds on formation of various neodymium and cerium phosphates

    Microsoft Academic Search

    Hiroaki Onoda; Atsushi Takenaka; Kazuo Kojima; Hiroyuki Nariai

    2003-01-01

    The mixture of rare earth oxide (Nd2O3 or CeO2), phosphorus compound ((NH4)2HPO4 or H3PO4), and an additive (urea: CO(NH2)2, biuret: NH(CONH2)2, cyanuric acid: (CONH)3, or ammonium hydrogencarbonate: NH4HCO3) was heated at 700°C for 3h. And then thermal products were analyzed by X-ray diffraction and Fourier transform infrared spectroscopy. In the system of Nd2O3–(NH4)2HPO4, the addition of urea had a little

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  19. The surfactant addition effect in the elaboration of electrodepositated NiP-SiC composite coatings

    Microsoft Academic Search

    C. F. Malfatti; H. M. Veit; T. L. Menezes; J. Zoppas Ferreira; J. S. Rodriguês; J.-P. Bonino

    2007-01-01

    In this work, NiP-SiC composite coatings were prepared by electrodeposition from a plating bath containing NiSO4·6H2O; NiCl2·6H2O; H3PO3; H3PO4; Na2SO4 and SiC particles (average diameter of 600 nm) in suspension. Anionic surfactant (SDS — sodium dodecyl sulfate, CH3(CH2)11SO4Na) or cationic surfactant (CTAHS — cetyltrimethylammonium hidrogensulfate, C19H43NO4S) were also added to this suspension. The number of incorporated particles by area unit (?np\\/A)

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

    PubMed

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

    2011-11-01

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

  1. Phosphoric acid and sodium fluoride: a novel etching combination on titanium.

    PubMed

    Jia, Fang; Zhou, Lei; Li, Shaobin; Lin, Xi; Wen, Binxue; Lai, Chunhua; Ding, Xianglong

    2014-06-01

    We investigate whether a novel and inexpensive etching method, H3PO4 + NaF, on titanium could obtain both a lower hydrogen content and superior calcium phosphate deposition performance, while achieving similar surface roughness in comparison with the traditional etching method. Pure titanium samples were treated with different concentrations of H3PO4 + NaF at ambient temperature without auxiliary implementations (groups A, B and C), and were treated using the traditional method (group T). The samples were then maintained in simulated body fluid for 10 and 20 days. The surface morphology and chemistry, as well as the hydrogen content and distribution, were studied. The hydrogen content of the new groups are in the range of 31 (3.6)-86.9 (7.2) ppm, and that of group T is 287 (13.5) ppm. The amount of deposited calcium phosphates increases as the hydrogen content approaches 90 ppm; however, this trend does not apply as the hydrogen content exceeds 90 ppm. The surface roughnesses of groups A, B and C are in the range of 0.47 (0.01)-0.92 (0.05) µm. The new surface topography regularly transforms, and the surfaces with round pits exert a better effect on the deposition of calcium phosphates than the surfaces with sharp cusps. PMID:24704898

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed

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

    2014-11-01

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

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

    PubMed

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

    2015-01-21

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

  5. Rare earth phosphate powders RePO 4· nH 2O ( Re=La, Ce or Y)—Part I. Synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Lucas, S.; Champion, E.; Bregiroux, D.; Bernache-Assollant, D.; Audubert, F.

    2004-04-01

    Rare earth phosphate powders ( Re=La, Ce or Y) were synthesized from an aqueous precipitation method. The effect of temperature, pH, ripening time and Re/P mole ratio of the initial reagents was investigated. Elementary analysis, surface area and bulk density measurements, FT-infrared spectroscopy, X-ray diffraction and SEM observations were performed to characterize the precipitates. All the powders of hydrated form (La, Ce or Y)PO 4· nH 2O were single phase. They exhibited a Re/P mole ratio smaller than 1 due to residual H 3PO 4 adsorbed at their surface. A unit formula could be written as RePO 4· nH 2O·(H 3PO 4) x with n?0.5 (for Re=La or Ce) or n=2 (for Re=Y) and x<0.1. High-temperature thermogravimetry was necessary to detect these residuals and insure the purity of the powders. The precipitation of lanthanum or cerium phosphates was slow, resulting in powders with a high specific surface. The precipitation of yttrium phosphate was faster and significant crystal growth occurred during the ripening, which resulted in a whisker-like morphology and a very low specific surface.

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

    NASA Astrophysics Data System (ADS)

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  9. Influence of porous texture and surface chemistry on the CO? adsorption capacity of porous carbons: acidic and basic site interactions.

    PubMed

    Sánchez-Sánchez, Angela; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M D

    2014-12-10

    Doped porous carbons exhibiting highly developed porosity and rich surface chemistry have been prepared and subsequently applied to clarify the influence of both factors on carbon dioxide capture. Nanocasting was selected as synthetic route, in which a polyaramide precursor (3-aminobenzoic acid) was thermally polymerized inside the porosity of an SBA-15 template in the presence of different H3PO4 concentrations. The surface chemistry and the porous texture of the carbons could be easily modulated by varying the H3PO4 concentration and carbonization temperature. Porous texture was found to be the determinant factor on carbon dioxide adsorption at 0 °C, while surface chemistry played an important role at higher adsorption temperatures. We proved that nitrogen functionalities acted as basic sites and oxygen and phosphorus groups as acidic ones toward adsorption of CO2 molecules. Among the nitrogen functional groups, pyrrolic groups exhibited the highest influence, while the positive effect of pyridinic and quaternary functionalities was smaller. Finally, some of these N-doped carbons exhibit CO2 heats of adsorption higher than 42 kJ/mol, which make them excellent candidates for CO2 capture. PMID:25347795

  10. Optimization of zinc phosphate coating on 7075-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

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

    1995-12-01

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

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

    PubMed

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

    2015-10-01

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

  12. A boron phosphate-phosphoric acid composite membrane for medium temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Mamlouk, M.; Scott, K.

    2015-07-01

    A composite membrane based on a non-stoichiometric composition of BPO4 with excess of PO4 (BPOx) was synthesised and characterised for medium temperature fuel cell use (120-180 °C). The electrolyte was characterised by FTIR, SS-NMR, TGA and XRD and showed that the B-O is tetrahedral, in agreement with reports in the literature that boron phosphorus oxide compounds at B:P < 1 are exclusively built of borate and phosphate tetrahedra. Platinum micro electrodes were used to study the electrolyte compatibility and stability towards oxygen reduction at 150 °C and to obtain kinetic and mass transport parameters. The conductivities of the pure BPOx membrane electrolyte and a Polybenzimidazole (PBI)-4BPOx composite membrane were 7.9 × 10-2 S cm-1 and 4.5 × 10-2 S cm-1 respectively at 150 °C, 5%RH. Fuel cell tests showed a significant enhancement in performance of BPOx over that of typical 5.6H3PO4-PBI membrane electrolyte. The enhancement is due to the improved ionic conductivity (3×), a higher exchange current density of the oxygen reduction (30×) and a lower membrane gas permeability (10×). Fuel cell current densities at 0.6 V were 706 and 425 mA cm-2 for BPOx and 5.6H3PO4-PBI, respectively, at 150 °C with O2 (atm).

  13. Orosensory Responsiveness to and Preference for Hydroxide-Containing Salts in Mice

    PubMed Central

    St. John, Steven J.; Boughter, John D.

    2009-01-01

    Historically, taste researchers have considered the possibility that the gustatory system detects basic compounds, such as those containing the hydroxide ion, but evidence for an “alkaline taste” has not been strong. We found that, in 48 h, 2-bottle preference tests, C3HeB/FeJ (C3) mice showed a preference for Ca(OH)2, whereas SWR/J (SW) mice showed avoidance. Strain differences were also apparent to NaOH but not CaCl2. Follow-up studies showed that the strain difference for Ca(OH)2 was stable over time (Experiment 2) but that C3 and SW mice did not differ in their responses to Ca(OH)2 or NaOH in brief-access tests, where both mice avoided high concentrations of these compounds (Experiment 3). In order to assess the perceived quality of Ca(OH)2, mice were tested in 2 taste aversion generalization experiments (Experiments 4 and 5). Aversions to Ca(OH)2 generalized to NaOH but not CaCl2 in both strains, suggesting that the generalization was based on the hydroxide ion. Both strains also generalized aversions to quinine, suggesting the possibility that the hydroxide ion has a bitter taste quality to these mice, despite the preference shown by C3 mice to middle concentrations in long-term tests. PMID:19423656

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

    PubMed

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

    2014-04-01

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

  15. Laboratory-scale inactivation of African swine fever virus and swine vesicular disease virus in pig slurry.

    PubMed

    Turner, C; Williams, S M

    1999-07-01

    Two methods were evaluated for the inactivation of African swine fever (ASV) and swine vesicular disease (SVD) viruses in pig slurry: chemical treatment and heat treatment. The addition of NaOH or Ca(OH)2 at different concentration/time combinations at 4 degrees C and 22 degrees C was examined, as was virus stability at different temperature/time combinations. ASF virus (ASFV) was less resistant to both methods than SVD virus (SVDV). In slurry from one source, ASFV was inactivated at 65 degrees C within 1 min, whereas SVDV required at least 2 min at 65 degrees C. However, it was found that thermal inactivation depended on the characteristics of the slurry used. Addition of 1% (w/v) of NaOH or Ca(OH)2 caused the inactivation of ASFV within 150 s at 4 degrees C; 0.5% (w/v) NaOH or Ca(OH)2 required 30 min for inactivation. NaOH or Ca(OH)2 (1% (w/v)) was not effective against SVDV at 22 degrees C after 30 min, and 1.5% (w/v) NaOH or Ca(OH)2 caused inactivation of SVDV at both 4 degrees C and 22 degrees C. At higher chemical concentrations or temperatures, ASFV and SVDV inactivation was faster in slurry than in buffered medium. PMID:10432596

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

    PubMed

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

    2011-09-15

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

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

    PubMed

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

    2009-10-15

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

  18. Effect of calcium hydroxide as an intracanal dressing on apical leakage.

    PubMed

    Cali?kan, M K; Türkün, M; Türkün, L S

    1998-05-01

    In this in vitro study, we investigated the effects of the use of two different calcium hydroxide (Ca(OH)2) preparations as an intracanal dressing on the sealing ability of two different sealers were investigated. Eighty-eight freshly extracted, single-rooted maxillary anterior teeth were used. After the root canals were hand-instrumented, they were divided into six groups of 10 each. The root canals were dressed with Ca(OH)2 paste, either mixed with sterile water (in groups 1 and 2) or with glycerine (in groups 3 and 4). The dressed root canals were incubated in 100% humidity at 37 degrees C for 7 days. In groups 5 and 6, the root canals were not dressed. After the root canal dressings were removed by irrigation with 5.25% NaOCl and reaming with a K-type file, all canals of the experimental groups were obturated with sealer and gutta-percha using a cold lateral condensation technique. Calciobiotric Root Canal Sealer, (CRCS), (in groups 1, 3 and 5) and Diaket (in groups 2, 4 and 6) were used as sealers. All specimens were placed in India ink for 7 days, and the amount of apical leakage was scored. Eight further prepared specimens were dressed with Ca(OH)2 plus water or Ca(OH)2 plus glycerine and examined with scanning electron microscopy (SEM) following the removal of dressings. There was a statistical difference in the leakage patterns amongst the 6 experimental groups (P < 0.05). Specimens in group 2 exhibited less leakage than the other experimental groups, except group 4 (P < 0.05). There were no other significant interactions. SEM examination revealed that Ca(OH)2 crystals were present on the surface of smear layer in both groups where Ca(OH)2 paste had been placed, but they did not penetrate into the dentinal tubules. PMID:10321163

  19. Thermochemical energy storage for a lunar base

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  20. Calcium

    Microsoft Academic Search

    R. P. Vetanovetz; J. C. Peterson

    1987-01-01

    Reagent grade CaCO3 or Ca(OH)2 was mixed at various rates into a medium consisting of 50% Canadian Sphagnum peat moss, 35% coarse perlite, and 15% sterile sand by volume. After 2 weeks incubation at 20C, medium pH levels were 4.32, 5.00, 6.55, and 7.22 for CaCO3?amended media, 3.98, 5.13, 6.30 and 6.75 for Ca(OH)2?amended media, and 3.42 for an unlimed

  1. Improved molecular weight control in ring-opening metathesis polymerization (ROMP) reactions with ru-based olefin metathesis catalysts using N donors and acid: a kinetic and mechanistic investigation.

    PubMed

    Dunbar, Miles A; Balof, Shawna L; LaBeaud, Lawrence J; Yu, Bing; Lowe, Andrew B; Valente, Edward J; Schanz, Hans-Jörg

    2009-11-16

    The effect of the addition of H(3)PO(4) on the ROMP activity of cyclooctene (COE) with first- [Cl(2)(PCy(3))(2)Ru=CHPh] and second-generation [(H(2)IMes)Cl(2)(PCy(3))Ru=CHPh] Grubbs' catalysts 1 and 4 (Cy=cyclohexyl, Ph=phenyl, Mes=2,4,6-trimethylphenyl (mesityl)), their inhibited mixtures with 1-methylimidazole (MIM), as well as their isolated bis-N,N'-dimethylaminopyridine (DMAP) derivatives [Cl(2)(PCy(3))(DMAP)(2)Ru=CHPh)] (5 b) and [Cl(2)(H(2)IMes)(DMAP)(2)Ru=CHPh] (7 b) (DMAP=dimethylaminopyridine), a novel catalyst, has been investigated. The studies include the determination of their initiation rates, as well as a determination of the molecular weights and molecular weight distributions of the polymers obtained with these catalysts and catalyst mixtures from the exo-7-oxanorbornene derivative 11. The structure of catalyst 7 b was confirmed by means of X-ray diffraction. All N-donor-bearing catalysts or N-donor-containing catalyst mixtures not only exhibited elevated activity in the presence of acid, but also increased initiation rates. Using the reversible inhibition/activation protocol with MIM and H(3)PO(4) enabled us to conduct controlled ROMP with catalyst 4 producing the isolated exo-7-oxanorbornene-based polymer 12 with predetermined molecular weights and narrow molecular weight distributions. This effect was based on fast and efficient catalyst initiation in contrast to the parent catalyst 4. Hexacoordinate complex 5 b also experienced a dramatic increase in initiation rates upon acid-addition and the ROMP reactions became well-controlled in contrast to the acid-free reaction. In contrast, complex 7 b performs well-controlled ROMP in the absence of acid, whereas the polymerization of the same monomer becomes less controlled in the presence of H(3)PO(4). The closer evaluation of catalysts 5 b and 7 b demonstrated that their initiation rates exhibit a linear dependency on the substrate concentration in contrast to catalysts 1 and 4. As a consequence, their initiation rates are determined by an associative step, not a dissociative step as seen for catalysts 1 and 4. A feasible associative metathesis initiation mechanism is proposed. PMID:19821457

  2. Acid and alkali doped PBI electrolyte in electrochemical system

    NASA Astrophysics Data System (ADS)

    Xing, Baozhong

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

  3. Thiol-Dependent passive K\\/Cl transport in sheep red cells: IV. Furosemide inhibition as a function of external Rb + , Na + , and Cl ?

    Microsoft Academic Search

    P. K. Lauf

    1984-01-01

    Summary The effect of the loop diuretic furosemide (4-chloro-N-furfuryl-5-sulfamoyl-anthranilic acid) on the thiol-dependent, ouabain-insensitive K(Rb)\\/Cl transport in low K+ sheep red cells was studied at various concentrations of extracellular Rb+, Na+ and Cl-. In Rb+-free NaCl media, 2×10-3m furosemide inhibited only one-half of thiol-dependent K+ efflux. In the presence of 23mm RbCl, however, the concentration of furosemide to produce 50%

  4. N-Methyl-d-aspartate Receptor- and Calpain-mediated Proteolytic Cleavage of K+-Cl? Cotransporter-2 Impairs Spinal Chloride Homeostasis in Neuropathic Pain*

    PubMed Central

    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

    2012-01-01

    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 (Eglycine) in spinal dorsal horn neurons. Blocking glutamate N-methyl-d-aspartate (NMDA) receptors normalizes synaptic inhibition, Eglycine, 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 Eglycine. 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

  5. Titanium subhydride potassium perchlorate (TiH1.65/KClO4) burn rates from hybrid closed bomb-strand burner experiments.

    SciTech Connect

    Cooper, Marcia A.; Oliver, Michael S.

    2012-08-01

    A hybrid closed bomb-strand burner is used to measure the burning behavior of the titanium subhydride potassium perchlorate pyrotechnic with an equivalent hydrogen concentration of 1.65. This experimental facility allows for simultaneous measurement of the closed bomb pressure rise and pyrotechnic burn rate as detected by electrical break wires over a range of pressures. Strands were formed by pressing the pyrotechnic powders to bulk densities between 60% and 90% theoretical maximum density. The burn rate dependance on initial density and vessel pressure are measured. At all initial strand densities, the burn is observed to transition from conductive to convective burning within the strand. The measured vessel pressure history is further analyzed following the closed bomb analysis methods developed for solid propellants.

  6. Excitation profile of coherent anti-Stokes Raman scattering from the MnO - 4 ion doped in a KClO4 crystal at low temperature

    NASA Astrophysics Data System (ADS)

    Leuchs, M.; Kiefer, W.

    1993-11-01

    We have performed polarized resonance coherent anti-Stokes Raman experiments on the permanganate ion doped in potassium perchlorate single crystals at temperature T=15 K. At this temperature the m (Cs) site splitting of the excited degenerate 1T2-electronic level of the permanganate ion and the vibronic structure are well resolved. We report on the A'-?1 coherent anti-Stokes Raman excitation profile which shows a strong dependence on the frequency of the pump laser. The simulation of the experimental results is performed by using the transform theory, which enables one to calculate the resonance Raman excitation profile solely from the measured absorption spectrum. According to the well known relation between the third-order nonlinear susceptibility and the Raman polarizability the coherent anti-Stokes excitation profile is given by a simple product of two Raman excitation profiles which are shifted relative to each other. The linear and the quadratic electron-phonon coupling as well as the influence of non-Condon terms were taken into account. Since the transform theory is mode selective in case there are no mode mixing effects the results derived from the description of the Raman excitation profiles and the coherent anti-Stokes excitation profiles are more definite. For this purpose one only needs the model parameters of the mode of interest. The simulation of the A'-?1 coherent anti-Stokes profile shows that a small amount of non-Condon coupling yields to a better agreement with the experiment.

  7. O2 volumes at high pressure from KClO4 decomposition: D? as a siderophile element pump instead of a lid on the core

    NASA Astrophysics Data System (ADS)

    Walker, D.; Clark, S. M.; Cranswick, L. M. D.; Johnson, M. C.; Jones, R. L.

    2002-11-01

    New measurements of the high-pressure volume of oxygen make plausible old, controversial diamond anvil cell (DAC) observations of a high-pressure reaction between liquid Fe and Fe-bearing silicate in which FeO dissolved into liquid Fe. If the Earth's D? layer between core and mantle is the waste product of this reaction proceeding forward with oxygen transfer to the core, then D? would form an effective lid preventing escape of siderophile elements from the core. On the other hand, it is at least as plausible that the core is now oxygen saturated and that core cooling and internal crystallization drive this reaction backward with transfer of Fe- and O-rich material out of the core into D?. The 186Os anomalies in some plume basalts are more consistent with this D? as a siderophile element pump scenario than the D? as-lid scenario. Contributions of siderophile elements to the mantle from the core could assist in balancing the persistently enigmatic budget of these elements.

  8. Low-temperature absorption and resonance Raman spectra of the MnO-4 ion doped in a KClO4 crystal

    NASA Astrophysics Data System (ADS)

    Leuchs, M.; Kiefer, W.

    1993-12-01

    We have performed polarized absorption and resonance Raman experiments on a permanganate ion doped in a potassium perchlorate single crystal at temperature T=15 K. At this low temperature the m(Cs) site splitting of the excited degenerate 1T2 electronic level of the permanganate ion is well resolved and the amount of splitting is about 40 cm-1. Due to the electronic configuration, one would expect that non-Condon terms have to be considered in the description of the absorption spectrum. For the theoretical simulation of our experimental results we have used expressions derived from the time-correlator formulation for the optical absorption. These are much easier to handle and they cause significant shorter calculation times than the usual sum-over-states expressions. In order to determine the symmetries and the wave-number positions of the site-split permanganate vibrations, we have performed resonance Raman experiments. The results obtained from these experiments form the basis for the interpretation of the absorption spectrum. The applied model includes the linear and quadratic electron-phonon and linear non-Condon coupling. Within this model we describe the multimode system and we show how a normal vibration, which apparently has no significant effects in the absorption spectrum, influences the discussion of the model system. For the fully symmetric breathing mode of the permanganate ion, we have calculated the change of the Mn-O equilibrium bond length in the electronic excited state from the corresponding linear electron-phonon coupling constant to be 4.6+/-0.4 pm.

  9. Potassium Chloride Enhances Fruit Appearance and Improves Quality of Fertigated Greenhouse Tomato as Compared to Potassium Nitrate

    Microsoft Academic Search

    B. P. Chapagain; Z. Wiesman; M. Zaccai; P. Imas; H. Magen

    2003-01-01

    The effects of potassium chloride (KCl) as a potassium (K) source in fertigation solution on growth, yield and quality of tomato (cv. Durinta) in a controlled greenhouse were compared with potassium nitrate (KNO3)—the conventional K source for vegetable fertigation. The treatments consisted of four levels of KCl: (1) 0% KCl (100% KNO3), (2) 40% KCl (40% KCl and 60% KNO3),

  10. Geochemistry of Extremely Alkaline (pH[ 12) Ground Water in Slag-Fill Aquifers

    E-print Network

    Bethke, Craig

    into the water and thick layers of calcite form. Iron, manganese, and other metals in the metallic portion with Ca(OH)2. Where the alkaline ground water discharges in springs, atmospheric CO2 dis- solves of heavy metals, suggest- ing that metals can move through the system as particulate matter. Air sparging

  11. Zentrum f ur Technomathematik Fachbereich 3 --Mathematik und Informatik

    E-print Network

    Bremen, Universität

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

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  14. 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 ...

  15. 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...

  16. 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...

  17. 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...

  18. The Canadian Mineralogist Vol. 46, pp. 737-740 (2008)

    E-print Network

    Chakhmouradian, Anton

    2008-01-01

    Tuttle, who was then one of world's leading experimental petrologists and inventor of the Tuttle cold, carbonatites were not believed to be igneous rocks, and it was experiments at Penn State by Wyllie & Tuttle of the ternary system CaF2­Ca(OH)2­CaCO3 (Gittins & Tuttle 1964). Simultaneously, John coedited with Tuttle

  19. 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...

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

    EPA Science Inventory

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

  1. Estudio de la composición química de pericarpio de maíz con las técnicas XPS y EDAX

    Microsoft Academic Search

    J. L. Peña; A. Calderón

    XPS and EDAX surface techniques were used to determine the chemical composition of pericarp of crude maize and maize submissive a process of traditional nixtamalization varying the content of Ca(OH)2. Also maize with 1 and 2 % of NaOH and 1 % of KOH was used. With XPS it is observed that, pericarp crude and cooked are compound mainly of

  2. ON A PRIORI ERROR ESTIMATES FOR A TWO-PHASE MOVING-INTERFACE PROBLEM WITH KINETIC CONDITION

    E-print Network

    Eindhoven, Technische Universiteit

    -interface model with kinetic condition arising in the modeling of concrete carbonation. CO2 and humidity attack reaction CO2(g aq) + Ca(OH)2(s aq) CaCO3 + H2O; see [6] for details on the physics and chemistry concrete samples and reduce their protection to corrosion (i.e. the alkalinity) via the apparently harmless

  3. Autocatalysis in the formose reaction

    Microsoft Academic Search

    R. F. Socha; A. H. Weiss; M. M. Sakharov

    1980-01-01

    It has been found that carbohydrates naturally present in ppm quantities in paraformaldehyde are the cause of the autocatalysis in the formose reaction of paraformaldehyde solutions. Paraformaldehyde sublimed into Ca(OH)2 suspension was not transformed to sugars by formose reaction, only to methanol and formate by Cannizzaro reaction. A minute trace of glycolaldehyde — 3 ppm — was sufficient to initiate

  4. Effect of Wheat Straw Treated with Alkali on Ruminal Function and Lactational Performance of Dairy Cows1

    Microsoft Academic Search

    S. G. Haddad; R. J. Grant; S. D. Kachman

    1998-01-01

    Two experiments were conducted to evaluate the effects of wheat straw treated with alkali on ruminal function and lactational performance of dairy cows. In Experiment 1, four ruminally fistulated Holsteins cows ( X = 57 d of lactation) were fed four diets that contained 0, 20, 30, or 40% (dry basis) wheat straw treated with 3% NaOH plus 3% Ca(OH)2

  5. Antimicrobial Effects of Photodynamic Therapy on Patients with Necrotic Pulps and Periapical Lesion

    Microsoft Academic Search

    Aguinaldo Silva Garcez; Silvia Cristina Nuñez; Michael R. Hamblin; Martha Simões Ribeiro

    2008-01-01

    This study analyzed the antimicrobial effect of photodynamic therapy (PDT) in association with endodontic treatment. Twenty patients were selected. Microbiological samples were taken after accessing the canal, endodontic therapy, and PDT. At the end of the first session, the root canal was filled with Ca(OH)2, and after 1 week, a second session of the therapies was performed. Endodontic therapy gave

  6. CALCIUM OXIDE SINTERING IN ATMOSPHERES CONTAINING WATER AND CARBON DIOXIDE

    EPA Science Inventory

    The paper gives results of measurements of the effects of water vapor and CO2 on the sintering rate of nascent CaO, as a function of partial pressure and temperature using CaO prepared by rapid decomposition of CaCO3 and CA(OH)2. Each gas strongly catalyzed the sintering process ...

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

    PubMed

    Jennings, Edward W; Schell, Daniel J

    2011-01-01

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

  8. 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 ...

  9. Heat Adaptation and Ion Exchange in Bacillus megaterium Spores

    Microsoft Academic Search

    Gordon Alderton; P. A. Thompson; Neva Snell

    1964-01-01

    A new spore phenomenon is described in which induction of increased heat resistance occurs during the process of heating. In buffered environments the acid form of dormant mature bacterial spores shows a temperature dependent adaptation to heat which is correlated with the rate of uptake of Ca(OH)2 by titration at constant pH in neutral salt solution.

  10. Avaliação de resíduos da fabricação de enzimas nas características químicas de um Cambissolo

    Microsoft Academic Search

    Francisco Ribeiro; Rua Francisco Ribeiro; Ulisses José Ribeiro

    Resumo - Os resíduos industriais e biossólidos reaproveitados na agricultura possuem potencial par a melhorar as características químicas e físicas do s olo, e evitando perda via reciclagem destes resíduos. Co m o objetivo de avaliar a utilização de substrato da fermentação microbiana inativado com Ca(OH) 2, oriundo da fabricação de enzimas industriais (proteases), sobre as características químicas do s

  11. Extraction of citrus glucosides

    Microsoft Academic Search

    S. A. El-Nawawi

    1995-01-01

    Hesperidin and naringin were extracted from orange peel and grapefruit peel, respectively, by treating the peel with Ca(OH)2. The effect of maturity of the peel and recycling of the extracting liquor upon the yield of glucoside were investigated. The highest yields of hesperidin were obtained from orange peel extracted at the early season, increase in maturity led to a decrease

  12. Carbonation of alkaline paper mill waste to reduce CO2 greenhouse gas emissions into the atmosphere

    E-print Network

    Montes-Hernandez, German

    Carbonation of alkaline paper mill waste to reduce CO2 greenhouse gas emissions into the atmosphere carbonation mechanisms of an alkaline paper mill waste containing about 55 wt% portlandite (Ca(OH)2 for diverse industrial applications. This result demonstrates the possibility of using the alkaline liquid

  13. Impact of mitigation strategies on acid sulfate soil chemistry and microbial community.

    PubMed

    Wu, Xiaofen; Sten, Pekka; Engblom, Sten; Nowak, Pawel; Österholm, Peter; Dopson, Mark

    2015-09-01

    Potential acid sulfate soils contain reduced iron sulfides that if oxidized, can cause significant environmental damage by releasing large amounts of acid and metals. This study examines metal and acid release as well as the microbial community capable of catalyzing metal sulfide oxidation after treating acid sulfate soil with calcium carbonate (CaCO3) or calcium hydroxide (Ca(OH)2). Leaching tests of acid sulfate soil samples were carried out in the laboratory. The pH of the leachate during the initial flushing with water lay between 3.8 and 4.4 suggesting that the jarosite/schwertmannite equilibrium controls the solution chemistry. However, the pH increased to circa 6 after treatment with CaCO3 suspension and circa 12 after introducing Ca(OH)2 solution. 16S rRNA gene sequences amplified from community DNA extracted from the untreated and both CaCO3 and Ca(OH)2 treated acid sulfate soils were most similar to bacteria (69.1% to 85.7%) and archaea (95.4% to 100%) previously identified from acid and metal contaminated environments. These species included a Thiomonas cuprina-like and an Acidocella-like bacteria as well as a Ferroplasma acidiphilum-like archeon. Although the CaCO3 and Ca(OH)2 treatments did not decrease the proportion of microorganisms capable of accelerating acid and metal release, the chemical effects of the treatments suggested their reduced activity. PMID:25933291

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

    PubMed

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

    2014-11-01

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

  15. Plasma chemical degradation of phosphorous-containing warfare agents simulants.

    PubMed

    Pascal, Sarah; Moussa, David; Hnatiuc, Eugen; Brisset, Jean-Louis

    2010-03-15

    The gliding electric discharge (or "glidarc") technique is a new advanced oxidation process used for the degradation of organic solutes or spent solvents. Discharges in humid air at atmospheric pressure produce active species (i.e., .OH and .NO) that are able to oxidize organic target up to carbon oxides and water. Aqueous solutions of triethylphosphate (TEP), a warfare agent simulant, are exposed to a glidarc in humid air to evaluate the solute stability under the impinging flux of active species. TEP was degraded and the overall zero order kinetic rate (k(0)=3.4 x 10(-4)mol h(-1)) was compared with that of previously considered tributylphosphate. The total degradation of TEP is monitored by the formation of H(3)PO(4) as the ultimate oxidation product of phosphorus by total organic carbon measurements. Extra investigation was performed on dimethylmethylphosphonate to examine the potential influence of the molecule symmetry on the degradation rate. PMID:19962821

  16. Recovery of ammonium nitrogen from the effluent of UASB treating poultry manure wastewater by MAP precipitation as a slow release fertilizer

    Microsoft Academic Search

    Kaan Yetilmezsoy; Zehra Sapci-Zengin

    2009-01-01

    Magnesium ammonium phosphate hexahydrate (MgNH4PO4·6H2O, MAP) precipitation was studied on up-flow anaerobic sludge blanket (UASB) pretreated poultry manure wastewater in a lab-scale batch study. To recover high strength of ammonium nitrogen (NH4+–N=1318mg\\/L) from UASB effluent, three combinations of chemicals including MgCl2·6H2O+KH2PO4, MgSO4·7H2O+NaHPO4·7H2O, and MgO+85% H3PO4 were first applied at the stoichiometric ratio (Mg2+:NH4+–N:PO43?–P=1:1:1) and at different pH levels ranging from

  17. Ab initio calculations of proton transfer in dimethylformamide-phosphoric acid complexes of 1 : 1 composition

    NASA Astrophysics Data System (ADS)

    Krestyaninov, M. A.; Kiselev, M. G.; Safonova, L. P.

    2015-04-01

    The energy parameters of the reactions that result from adding protons to phosphoric acid, its dimer, and dimethylformamide; the reactions of the formation of phosphoric acid dimers and dimethylformamide-phosphoric acid complexes; and reactions involving the protonated forms of dimethylformamide and acid are calculated by means of DFT B3LYP using the 6-31++G( d, p) basis set. The structural characteristics of the complexes and transitional states are calculated along with the change in energy upon proton transfer. The effect media have on the energy characteristics of proton transfer is studied. It is found the energy barrier of proton transfer grows upon an increase in the O⋯O distance. It is concluded that the lowest energy barriers of proton transfer are expected for DMFH+⋯DMF and H3PO4⋯H2PO{4/-} complexes.

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

    PubMed

    Matos, Juan; Montaña, Ricmary; Rivero, Eliram

    2015-01-01

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

  19. Microscale steps and micro-nano combined structures by anodizing aluminum

    NASA Astrophysics Data System (ADS)

    Ding, G. Q.; Yang, R.; Ding, J. N.; Yuan, N. Y.; Shen, W. Z.

    2010-08-01

    In this paper, we firstly present a novel microscale-step structure fabricated by anodizing aluminum in a mixture of 0.05-0.5 wt% NaCl (HCl), 2 wt% H 3PO 4 and 20 wt% ethanol under potentials of 1-40 V at room temperature. Then, we present two micro-nano combined structures by integrating the microsteps with nanopores through multi-step anodizations. The microstep-nanopore hierarchical structure was obtained by re-anodizing the sample in oxalic acid, and the regular nanopores can be realized on the microscale patterned aluminum surface. The two-layer porous structure was one layer of nanoporous anodic alumina and another layer of micropores by two-step anodization on sample's both sides. These two novel structures can be useful for surface engineering and high flux filtration, respectively. The current fabrication approach broadens the applications of aluminum anodization, and brings a new method for assembling micro-nano structures.

  20. Exceeding 20,000-fold concentration of protein by the on-line isotachophoresis concentration in poly(methyl methacrylate) microchip.

    PubMed

    Wang, Jun; Zhang, Yong; Mohamadi, Mohamad Reza; Kaji, Noritada; Tokeshi, Manabu; Baba, Yoshinobu

    2009-09-01

    In this research, a simple on-line microchip gel electrophoresis with ITP was applied for the concentration and separation of BSA and its immunoassay complex with mAb in a single cross form PMMA microchip. We investigated the ITP concentration effect in PMMA MCE using combination of leading electrolytes, terminating electrolytes and other factors. We realized an ITP-based concentration and separation of BSA and its immunoassay complexes in standard cross-channel microchip gel electrophoresis, which exceeded 2000-fold concentration of BSA immunocomplex using Tris-H3PO4 as a leading electrolyte and Tris-gamma-amino butyric acid as a terminating electrolyte. In addition, we also realized concentration of BSA sample in water, which was more than 20 000-fold and was the result of the concentration effect from combining ITP and the sample stacking techniques. PMID:19722200

  1. Fuel cell applied research: Electrocatalysis and materials

    NASA Astrophysics Data System (ADS)

    Srinivasan, S.; Isaacs, H.; McBreen, J.; Ogrady, W. E.; Olender, H.; Olmer, L. J.; Schouler, E. J. L.; Adzic, R. R.

    1980-03-01

    The effect of underpotential deposited metal layers on the electrocatalysis of fuel cell reactions is studied. The potential for developing organic compound/air fuel cells using underpotential deposited Pb adatoms to enhance the electrocatalysis of the fuel electrode is explored. The effects of adsorbed layers of Pb, Tl and Bi on formic acid and methanol oxidation on platinum in 85 percent H3PO4 were investigated. The effect of crystal orientation on formic acid oxidation on platinum in 1 M CHlO2 was investigated. The kinetics of the oxygen reduction and evolution reactions at the electrode (metal or oxide) solid electrolyte (yttria stabilized zirconia) interface were investigated using ac and dc techniques.

  2. Redetermination of AgPO3

    PubMed Central

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

    2011-01-01

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

  3. The fractionation of noble gases in diamonds of CV3 Efremovka chondrite

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Verchovsky, A. B.; Semjonova, L. F.; Shukolyukov, Yu. A.

    1993-01-01

    It was shown that in diamonds of Efremovka CV3 the noble gases with normal isotopic compositions are fractionated in different degree while the correlation of isotopic anomalous components is nearly constant. Some data for noble gases in DE-4 sample of Efremovka chondrite are considered. In contrast to DE-2 sample the DE-4 was treated except conc. HClO4, 220 C in addition with mixture of conc. H2SO4+H3PO4 (1:1), 220 C, twice. Noble gases analysis were performed in Germany at Max Plank Institute fur Chemie. Noble gases were released by oxidation of samples at stepped heating from 420 C to 810 C and by pyrolysis at 580, 590, and 680 C.

  4. Simple and sensitive high-performance liquid chromatographic method for the determination of 1,5-benzodiazepine clobazam and its active metabolite N-desmethylclobazam in human serum and urine with application to 1,4-benzodiazepines analysis.

    PubMed

    Kunicki, P K

    2001-01-01

    A HPLC-UV determination of clobazam and N-desmethylclobazam in human serum and urine is presented. After simple liquid-liquid extraction with dichloromethane the compounds and an internal standard diazepam were separated on a Supelcosil LC-8-DB column at ambient temperature under isocratic conditions using the mobile phase: CH3CN-water-0.5 M KH2PO4-H3PO4 (440:540:20:0.4, v/v and 360:580:60:0.4, v/v for serum and urine, respectively). The detection was performed at 228 nm with limits of quantification of 2 ng/ml for serum and 1 ng/ml for urine. Relative standard deviations for intra- and inter-assay precision were found below 8% for both compounds for all the tested concentrations. The described procedure may be easily adapted for several 1,4-benzodiazepines. PMID:11204222

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

    PubMed

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

    2011-04-01

    A coupled high performance liquid chromatography-hydride generation-atomic absorption spectroscopy system was used to determine the speciation of arsenic in samples from the Nha Trang Harbor, Vietnam. Concentrations of arsenic in seawater, pore water, suspended solid, and sediment were 4.12-9.81 ?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

  6. Highly Flexible and Planar Supercapacitors Using Graphite Flakes/Polypyrrole in Polymer Lapping Film.

    PubMed

    Raj, C Justin; Kim, Byung Chul; Cho, Won-Je; Lee, Won-Gil; Jung, Sang-Don; Kim, Yong Hee; Park, Sang Yeop; Yu, Kook Hyun

    2015-06-24

    Flexible supercapacitor electrodes have been fabricated by simple fabrication technique using graphite nanoflakes on polymer lapping films as flexible substrate. An additional thin layer of conducting polymer polypyrrole over the electrode improved the surface conductivity and exhibited excellent electrochemical performances. Such capacitor films showed better energy density and power density with a maximum capacitance value of 37 mF cm(-2) in a half cell configuration using 1 M H2SO4 electrolyte, 23 mF cm(-2) in full cell, and 6 mF cm(-2) as planar cell configuration using poly(vinyl alcohol) (PVA)/phosphoric acid (H3PO4) solid state electrolyte. Moreover, the graphite nanoflakes/polypyrrole over polymer lapping film demonstrated good flexibility and cyclic stability. PMID:26010272

  7. Recovery of ammonium-nitrogen from landfill leachate as a multi-nutrient fertilizer

    Microsoft Academic Search

    X. Z Li; Q. L Zhao

    2003-01-01

    Leachates generated in Hong Kong landfill sites contain high strength of ammonium-nitrogen (NH4+-N) in the range of 2000–5000 mg l?1, which could be used to produce nitrogen-fertilizer. To recover the NH4+-N from the leachate, a lab-scale study was performed to investigate the efficiency of magnesium ammonium phosphate (MAP) precipitation using three combinations of chemicals: MgCl2·6H2O+Na2HPO4·12H2O, MgO+85% H3PO4 and MgSO4·7H2O+Ca(H2PO4)·H2O. The

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  9. Adsorption of phenols from wastewater.

    PubMed

    Ahmaruzzaman, M; Sharma, D K

    2005-07-01

    The present work involves an investigation of the possible use of coal, residual coal, and residual coal treated with H3PO4 as a means of removal of phenol from wastewater. The study was realized using batch experiments, with synthetic wastewater having phenol concentration of 1000 ppm. Other low-cost adsorbents such as petroleum coke, coke breeze, rice husk, and rice husk char have also been used. The effect of system variables such as pH, contact time, and temperature has been investigated. The suitability of the Freundlich, Langmuir, and Redlich-Peterson adsorption models to the equilibrium data was investigated for each phenol-adsorbent system. The results showed that the equilibrium data for all the phenol-sorbent systems fitted the Redlich-Peterson model best. Kinetic modeling of removal of phenols was done using the Lagergren first-order rate expression. A series of column experiments were performed to determine the breakthrough curves. PMID:15914144

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

    PubMed

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

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  12. NiO layers grown on a Ni substrate by galvanostatic anodization as a positive electrode material for aqueous hybrid capacitors

    NASA Astrophysics Data System (ADS)

    Chiku, Masanobu; Toda, Masanari; Higuchi, Eiji; Inoue, Hiroshi

    2015-07-01

    A NiO positive electrode for aqueous hybrid capacitors was prepared by a new galvanostatic anodization method. A thin sheet of heat-treated Ni was galvanostatically oxidized in aqueous 85% H3PO4 containing 0.5 M NH4F. During the anodization, the thickness of the Ni metal sheet decreased from 10 to 2 ?m and 2- to 3-?m-thick NiO layers were formed on both sides of the Ni metal sheet. A hybrid capacitor comprising the anodized NiO positive electrode, an activated carbon negative electrode, and aqueous 10 M KOH exhibited a maximum specific energy of 16 W h kg-1 and a specific power of 22.2 kW kg-1.

  13. Oxygen isotope analysis of carbonates in the calcite-dolomite-magnesite solid-solution by high-temperature pyrolysis: initial results.

    PubMed

    Crowley, Stephen F; Spero, Howard J; Winter, David A; Sloane, Hilary J; Croudace, Ian W

    2008-06-01

    Accurate and efficient measurement of the oxygen isotope composition of carbonates (delta(C) (18)O) based on the mass spectrometric analysis of CO(2) produced by reacting carbonate samples with H(3)PO(4) is compromised by: (1) uncertainties associated with fractionation factors (alpha(CO)(2)C) used to correct measured oxygen isotope values of CO(2)(delta(CO(2)(18)O) to delta(C) (18)O; and (2) the slow reaction rates of many carbonates of geological and environmental interest with H(3)PO(4). In contrast, determination of delta(C) (18)O from analysis of CO produced by high-temperature (>1400 degrees C) pyrolytic reduction, using an elemental analyser coupled to continuous-flow isotope-ratio mass spectrometry (TC/EA CF-IRMS), offers a potentially efficient alternative that measures the isotopic composition of total carbonate oxygen and should, therefore, theoretically be free of fractionation effects. The utility of the TC/EA CF-IRMS technique was tested by analysis of carbonates in the calcite-dolomite-magnesite solid-solution and comparing the results with delta(C) (18)O measured by conventional thermal decomposition/fluorination (TDF) on the same materials. Initial results show that CO yields are dependent on both the chemical composition of the carbonate and the specific pyrolysis conditions. Low gas yields (<100% of predicted yield) are associated with positive (>+0.2 per thousand) deviations in delta(C(TC/EA) (18)O compared with delta(C(TDF) (18)O. At a pyrolysis temperature of 1420 degrees C the difference between delta(C) (18)O measured by TC/EA CF-IRMS and TDF (Delta(C(TC/EA,TDF) (18)O) was found to be negatively correlated with gas yield (r = -0.785) and this suggests that delta(C) (18)O values (with an estimated combined standard uncertainty of +/-0.38 per thousand) could be derived by applying a yield-dependent correction. Increasing the pyrolysis temperature to 1500 degrees C also resulted in a statistically significant correlation with gas yield (r = -0.601), indicating that delta(C) (18)O values (with an estimated uncertainty of +/-0.43 per thousand) could again be corrected using a yield-dependent procedure. Despite significant uncertainty associated with TC/EA CF-IRMS analysis, the magnitude of the uncertainty is similar to that associated with the application of poorly defined values of alpha(CO)(2), (C) used to derive delta(C) (18)O from delta(CO(2) (18)O measured by the H(3)PO(4) method for most common carbonate phases. Consequently, TC/EA CF-IRMS could provide a rapid alternative for the analysis of these phases without any effective deterioration in relative accuracy, while analytical precision could be improved by increasing the number of replicate analyses for both calibration standards and samples. Although automated gas preparation techniques based on the H(3)PO(4) method (ISOCARB, Kiel device, Gas-Bench systems) have the potential to measure delta(CO)(2) (18)O efficiently for specific, slowly reacting phases (e.g. dolomite), problems associated with poorly defined alpha(CO)(2), (C) remain. The application of the Principle of Identical Treatment is not a solution to the analysis of these phases because it assumes that a single fractionation factor may be defined for each phase within a solid-solution regardless of its precise chemical composition. This assumption has yet to be tested adequately. PMID:18446821

  14. Development of Pillared M(IV) Phosphate Phosphonate Inorganic Organic Hybrid Ion Exchange Materials for Applications in Separations found in the Nuclear Fuel Cycle

    E-print Network

    Burns, Jonathan

    2012-10-02

    Grade, Ni(NO3)2?6H2O) was purchased from Matheson Coleman & Bell Manufacturing; tribasic potassium phosphate (?98%, K3PO4) and sodium persulfate (?98, Na2S2O8) were purchased from 20 Sigma-Aldrich; samarium nitrate hexahydrate (99.9%, Sm(NO3...)3?6H2O) and ytterbium nitrate hydrate (Yb(NO3)3?xH2O, 99.9%) were purchased from Alfa; phosphoric acid (ACS Grade, H3PO4) and sodium nitrate (99%, NaNO3) were purchased from EMD; sodium persulfate (98+%, Na2S2O8) was purchased from Acros; tribasic...

  15. Smectic phases in a binary mixture of two non-mesogenic compounds

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    The binary mixture of two non-mesogenic compounds viz., Tetradecyl Trimethyl Ammonium Bromide (TTAB) and Ortho-phosphoric acid (H3PO4) exhibits very interesting liquid crystalline smectic phases at large range of concentrations and temperatures. The mixture with wide range of concentrations of TTAB exhibits Sm A, Sm D, Sm B and Sm E phases sequentially, when the specimen is cooled from its isotropic phase. The different liquid crystalline phases of the mixture were also studied using DSC, X-ray and optical microscopic techniques. All the studies confirm the presence of the rare Sm E phase in the mixture. This type of polymorphism is very rare in the binary mixture of non-mesogenic compounds.

  16. Valorization of phosphogypsum as hydraulic binder.

    PubMed

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

    2008-12-30

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

  17. [H 2(C 4H 10N 2)] 2(H 2PO 4) 4: hydrothermal synthesis and single crystal structure of an inclusive supramolecular phosphoric salt

    Microsoft Academic Search

    Fa-Nian Shi; Zhen Shen; Xiao-Zeng You; Chun-Ying Duan

    2000-01-01

    The new supramolecular phosphoric complex [H2(C4H10N2)]2(H2PO4)4 has been obtained by the hydrothermal reaction of piperazine hexahydrate (C4H10N2·6H2O), Zn(OAc)2 with H3PO4 in the molar ratio of 1:1:2 at 180°C. The compound was characterized by the means of elemental analysis, FT-IR, TGA-DTA, and single crystal X-ray analysis. The structure was determined with data: triclinic, space group P-1(no. 2), a=7.020(9)A?,b=7.694(2)A?,c=12.076(2)A?,?=84.41°, ?=81.51°, ?=62.92(2)°, V=574.04(2)A?3,

  18. [In Process Citation].

    PubMed

    Louis, C; Bessiere, J

    1987-09-01

    The conditional potentials of redox systems not involving protons have been studied as a function of phosphoric acid concentration (1-14M), with the ferricinium/ferrocene couple as the comparison system. The following systems were considered: Cu(II)/Cu, Cd(II)/Cd, Sn(II)/Sn, Zn(II)/Zn, Ag(I)/Ag, Pb(II)/Pb, Hg(II)/Hg, Bi(III)/Bi and particularly Fe(III)/Fe(II) and Fe(II)/Fe. The hexacyanoferrate(III)/hexacyanoferrate(II) and iodine/iodide couples were also studied. The results are presented as a potential-H(3)PO(4) concentration diagram (or potential-acidity level diagram). PMID:18964403

  19. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid.

    PubMed

    Cao, Xinde; Wahbi, Ammar; Ma, Lena; Li, Bing; Yang, Yongliang

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H(3)PO(4) treatments (PA and PR+PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H(3)PO(4) was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced. PMID:18848390

  20. Management of Post-orthodontic White Spot Lesions and Subsequent Enamel Discoloration with Two Microabrasion Techniques

    PubMed Central

    Jahanbin, Arezoo; Ameri, Hamideh; Shahabi, Mostafa; Ghazi, Ala

    2015-01-01

    Statement of the Problem Demineralization of enamel adjacent to orthodontic appliances frequently occurs, commonly due to insufficient oral hygiene. Purpose The aim of this study was to compare two microabrasion techniques on improving the white spot lesions as well as subsequent enamel discoloration. Materials and Method Sixty extracted premolar teeth without caries and hypoplasia were selected for this study. White spot lesions were artificially induced on the buccal surface of each tooth. Teeth were randomly assigned to three treatment groups, each treated with pumice powder as the control, microabrasion with 18% HCl, and microabrasion with 37% H3PO4. Subsequently, the three groups were daily immersed for five minutes in a tea-coffee solution for a period of one week. Colorimetric evaluation was done before and after formation of white spot lesions, after microabrasion, and after immersion in the colored solution; then the color differences (?E) were calculated. Statistical analysis was performed by multiple measurement analysis and the Tukey’s test. Results This study showed that ?E between the stages of white spot formation and microabrasion for H3PO4 was more than other groups and for the pumice powder group it was less than the others. Furthermore, there was a significant difference between ?E of the three study groups (p= 0.017). Additionally, ?E after placing the teeth in the colored solution and microabrasion was the highest for the HCl group and the lowest for the pumice powder group. There was also a significant difference between the three groups (p= 0.000). Conclusion Pumice powder alone had similar effects as 18% HCl on removing the white spot lesions. Nevertheless, 18% HCl makes the enamel susceptible for subsequent color staining more than the other microabrasion methods.

  1. Enamel morphology after microabrasion with experimental compounds

    PubMed Central

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

    2015-01-01

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

  2. A capacitance sensor for water: trace moisture measurement in gases and organic solvents.

    PubMed

    Ohira, Shin-Ichi; Goto, Kayoko; Toda, Kei; Dasgupta, Purnendu K

    2012-10-16

    The determination of water in various matrices is one of the most important analytical measurements. We report on a high-resolution capacitance-based moisture sensor utilizing a thin film of a perfluorosulfonate ionomer (PFSI)-H(3)PO(4) composite in a flow-through configuration, for both gas and liquid samples. Incorporation of H(3)PO(4) into a PFSI sensing film improved the limit of detection (LOD) (signal-to-noise ratio, S/N = 3) by a factor of 16 in the gas phase to 0.075% relative humidity (RH) (dew point = -56 °C). The response time was dependent on the sensing film thickness and composition and was as low as ?60 ms. The temperature dependence of the sensor response, and its relative selectivity over alcohol and various other solvents, are reported. Measurement of water in organic solvents was carried out in two different ways. In one procedure, the sample was vaporized and swept into the detector (e.g., in a gas chromatograph (GC) without a column); it permitted a throughput of 80 samples/h. This is well-suited for higher (%) levels of water. In the other method, a flow injection analysis system integrated to a tubular dialysis membrane pervaporizer (PV-FIA) was used; the LOD for water in ethanol was 0.019% (w/w). We demonstrated the temporal course of drying of ethanol by Drierite; the PV-FIA results showed excellent correspondence (r(2) > 0.99) with results from GC-thermal conductivity detection. The system can measure trace water in many types of organic solvents; no reagent consumption is involved. PMID:22962839

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

    PubMed

    Liu, Y-Y; Haynes, R J

    2013-01-01

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

  4. OA02.02. Phytochemical constituents and antioxidative property of Musa acuminata flower as green corrosion inhibitor of mild steel in acid media

    PubMed Central

    Gunavathy, N

    2013-01-01

    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.

  5. In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments

    PubMed Central

    Yoldas, Oguz; Yilmaz, Sehnaz; Akcimen, Beril; Seydaoglu, Gulsah; Kipalev, Arzu; Koksal, Fatih

    2012-01-01

    The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments. Key words:E.faecalis, C.albicans, antimicrobial, antibiotic, antifungal. PMID:24558517

  6. The effect of nonsetting calcium hydroxide on root fracture and mechanical properties of radicular dentine: a systematic review.

    PubMed

    Yassen, G H; Platt, J A

    2013-02-01

    The aim of this review was to identify and analyse all studies related to the effect of nonsetting calcium hydroxide [Ca(OH)(2)] on root fracture and various mechanical properties of radicular dentine. A PubMed search was conducted using the keywords 'calcium hydroxide' and 'dentistry' combined with MeSH terms 'tooth fractures' or 'mechanical phenomena' or 'compressive strength'. The search was expanded by including Embase and Web of Science databases, using the keywords 'calcium hydroxide' and 'root' and 'fracture'. The search was supplemented by checking the reference lists from each selected article. Each study had to meet the following criteria to be selected for review: (i) Inclusion of at least one experimental group with root or radicular dentine either filled with or exposed to nonsetting Ca(OH)(2); (ii) inclusion of at least one appropriate control group; and (iii) a minimum of five samples per experimental group. Only articles written in English were included. Of the 16 studies selected initially, 12 in vitro studies fulfilled the selection criteria for inclusion in the final review. No clinical studies that directly supported the correlation between Ca(OH)(2) intracanal dressing and root fracture were found in the literature. However, the majority of in vitro studies showed reduction in the mechanical properties of radicular dentine after exposure to Ca(OH)(2) for 5 weeks or longer. Conversely, the data were inconclusive regarding whether Ca(OH)(2) exposure for 1 month or less had a negative effect on the mechanical properties of radicular dentine. PMID:22970899

  7. Thermo-chemical pre-treatment to solubilize and improve anaerobic biodegradability of press mud.

    PubMed

    López González, Lisbet Mailin; Vervaeren, Han; Pereda Reyes, Ileana; Dumoulin, Ann; Romero Romero, Osvaldo; Dewulf, Jo

    2013-03-01

    Different pre-treatment severities by thermo-alkaline conditions (100°C, Ca(OH)2) on press mud were evaluated for different pre-treatment time and lime loading. COD solubilization and the methane yield enhancement were assessed. The biochemical methane potential was determined in batch assays under mesophilic conditions (37±1°C). The best pre-treatment resulted in a surplus of 72% of methane yield, adding 10g Ca(OH)2 100g(-1)TS(-1) for 1h. Pre-treatment also increased the COD solubilization, but the optimal severity for COD solubilization as determined by response surface methodology did not ensure the highest methane production. Inhibitory effects on anaerobic digestion were noticed when the severity was increased. These results demonstrate the relevance of thermo-alkaline pre-treatment severity in terms of both lime loading and pre-treatment time to obtain optimal anaerobic biodegradability of lignocellulosic biomass from press mud. PMID:23353040

  8. Effect of prior calcium hydroxide intracanal placement on sealing ability of MTA plugs.

    PubMed

    Adel, Mamak; Majd, Nima Moradi; Samani, Yasaman

    2014-01-01

    This study sought to investigate how pretreatment intracanal placement of calcium hydroxide (Ca(OH)2) affected the sealing ability of mineral trioxide aggregate (MTA) plugs in simulated open apices. Maxillary central incisor teeth were cleaned and shaped in an identical manner. After root-end resection, samples were divided randomly into 2 control (n = 5) and 2 experimental groups (n = 35). The specimens in Group 1 were pretreated using a Ca(OH)2 medicament, while the samples of Group 2 received no medicament. One week later, a 5 mm apical plug of MTA was applied into the canals. The remaining portions of the canals were obturated with gutta percha. Group 1 had a significantly higher frequency of apical leakage than Group 2 (P < 0.05). PMID:24983183

  9. Laboratory Synthesized Calcium Oxide and Calcium Hydroxide Grains: A Candidate to Explain the 6.8 Micron Band

    NASA Technical Reports Server (NTRS)

    Kimura, Yuki; Nuth, Joseph A., III

    2005-01-01

    We will demonstrate that CaO and Ca(OH)2 are excellent candidates to explain the 6.8 microns feature, which is one of the most obscure features in young stellar objects. We discuss the condensation of CaO grains and the potential formation of a Ca(OH)2 surface layer. The infrared spectra of these grains are compared with the spectra of fifteen young stellar objects. We note that CaO-rich grains are seen in all meteoritic CAIs (calcium-aluminum-rich inclusions) and the 6.8 micron feature has only been observed in young stellar objects. Therefore, we consider CaO grains to be a plausible candidate to explain the 6.8 microns feature and hypothesize that they are produced in the hot interiors of young stellar environments.

  10. Rapid Carbonation for Calcite from a Solid-Liquid-Gas System with an Imidazolium-Based Ionic Liquid

    PubMed Central

    Ibrahim, Abdul-Rauf; Vuningoma, Jean Bosco; Huang, Yan; Wang, Hongtao; Li, Jun

    2014-01-01

    Aqueous carbonation of Ca(OH)2 is a complex process that produces calcite with scalenohedral calcite phases and characterized by inadequate carbonate species for effective carbonation due to the poor dissolution of CO2 in water. Consequently, we report a solid-liquid-gas carbonation system with an ionic liquid (IL), 1-butyl-3-methylimidazolium bromide, in view of enhancing the reaction of CO2 with Ca(OH)2. The use of the IL increased the solubility of CO2 in the aqueous environment and enhanced the transport of the reactive species (Ca2+ and CO32?) and products. The presence of the IL also avoided the formation of the CaCO3 protective and passivation layer and ensured high carbonation yields, as well as the production of stoichiometric rhombohedral calcite phases in a short time. PMID:24968273

  11. Formaldehyde reduction with scallop shell powders fired at high temperatures: Identification of the effective ingredient.

    PubMed

    Takada, Tomoya; Furusaki, Atsushi; Tanaka, Yasuaki

    2009-01-01

    The volatile organic compound (VOC) reduction activity of scallop shell powders fired at 300, 600 and 900 degrees C was examined using formaldehyde (HCHO). Raw shells as well as fired shells immediately after firing at several temperatures, except for 600 degrees C, were found to gradually remove HCHO from the air. In the case of shell powders stored for 3 months after firing, the HCHO reduction activity of the powder fired at 900 degrees C was obviously improved, with the HCHO concentrations rapidly reaching zero within 20 min. It has been found by X-ray diffraction measurements that shell powder stored for 3 months after firing at 900 degrees C contains a small amount of calcium hydroxide (Ca(OH)2) generated from calcium oxide (CaO). Our results suggest that Ca(OH)2 may be the effective ingredient in the HCHO reduction. PMID:19581713

  12. Effect of water–binder ratio on the mechanical properties of calcium hydroxide-based alkali-activated slag concrete

    Microsoft Academic Search

    Keun-Hyeok Yang; Ah-Ram Cho; Jin-Kyu Song

    This paper presents mechanical properties of calcium hydroxide (Ca(OH)2)-activated ground granulated blast-furnace slag (GGBS) concrete with different auxiliary activators in order to provide basic data for developing the mixing procedure and design models for structural concrete. Twelve concrete mixes were prepared with the main parameters of water–binder (W\\/B) ratio. The measured mechanical properties were compared, wherever possible, with design equations

  13. Characterization of fish gelatin from surimi processing wastes: Thermal analysis and effect of transglutaminase on gel properties

    Microsoft Academic Search

    M. H. Norziah; A. Al-Hassan; A. B. Khairulnizam; M. N. Mordi; M. Norita

    2009-01-01

    Fish gelatin extraction from wastes of fish Herring species (Tenualosa ilisha) was carried out by a series of pretreatment with 0.2M Ca(OH)2 followed by 0.1M citric acid and final water extraction at 50°C for 3h. The resulting fish gelatin preparation was evaluated for its dynamic viscoelastic properties, gelling and melting temperatures and gel strength. The gelling and melting temperatures of

  14. Activation of fly ash and its effects on cement properties 1 1 This article is being published without the benefit of the authors’ review of the proofs, which was not available at press time

    Microsoft Academic Search

    Yueming Fan; Suhong Yin; Zhiyun Wen; Jingyu Zhong

    1999-01-01

    A new method of fly ash activation with addition of Ca(OH)2 and a small quantity of Na2SiO3 is presented. Scanning electron microscopy, differential thermal analysis, x-ray diffraction analysis, alkali-absorption test, and strength measurement show that the activity of activated fly ash by this method is obviously increased, which can accelerate cement early hydration and promote setting and hardening.

  15. Mechanical and microstructural properties of alkali-activated fly ash geopolymers

    Microsoft Academic Search

    M. Komljenovi?; Z. Baš?arevi?; V. Bradi?

    2010-01-01

    This paper investigates the properties of geopolymer obtained by alkali-activation of fly ash (FA), i.e. the influence of characteristics of the representative group of FA (class F) from Serbia, as well as that of the nature and concentration of various activators on mechanical and microstructural properties of geopolymers. Aqueous solutions of Ca(OH)2, NaOH, NaOH+Na2CO3, KOH and sodium silicate (water glass)

  16. Pilot-scale waste activated sludge alkaline fermentation, fermentation liquid separation, and application of fermentation liquid to improve biological nutrient removal.

    PubMed

    Li, Xiang; Chen, Hong; Hu, Lanfang; Yu, Lei; Chen, Yinguang; Gu, Guowei

    2011-03-01

    The use of sludge fermentative short-chain fatty acids (SCFA) as an additional carbon source of biological nutrient removal (BNR) has drawn much attention recently as it can reuse sludge organics, reduce waste activated sludge production, and improve BNR performance. Our previous laboratory study had shown that the SCFA production was significantly enhanced by controlling sludge fermentation at pH 10 with NaOH. This paper focused on a pilot-scale study of alkaline fermentation of waste activated sludge, separation of the fermentation liquid from the alkaline fermentation system, and application of the fermentation liquid to improve municipal biological nitrogen and phosphorus removal. NaOH and Ca(OH)(2) were used respectively to adjust the alkaline fermentation pH, and their effects on sludge fermentation and fermentation liquid separation were compared. The results showed that the use of Ca(OH)(2) had almost the same effect on SCFA production improvement and sludge volatile suspended solids reduction as that of NaOH, but it exhibited better sludge dewatering, lower chemical costs, and higher fermentation liquid recovery efficiency. When the fermentation liquids, adjusted with Ca(OH)(2) and NaOH respectively, were added continuously to an anaerobic-anoxic-aerobic municipal wastewater BNR system, both the nitrogen and phosphorus removals, compared with the control, were improved to the same levels. This was attributed to the increase of not only influent COD but also denitrifying phosphorus removal capability. It seems that the use of Ca(OH)(2) to control sludge fermentation at pH 10 for efficiently producing a carbon source for BNR is feasible. PMID:21280571

  17. Differential scanning calorimetry study of hydrated ground granulated blast-furnace slag

    Microsoft Academic Search

    W. Sha; G. B. Pereira

    2001-01-01

    The present work involves using differential scanning calorimetry (DSC) in an investigation of the thermal behaviour of hydration products in ground granulated blast-furnace slag (ggbs). The two-step loss of water from calcium silicate hydrates and dehydroxylation of calcium hydroxide (Ca(OH)2) contribute, respectively, to the two major peaks in the DSC curves. Peaks due to the formation of ettringite and Fe2O3

  18. Evaluation of the growth and quality of the “Ife Plum” tomato as affected by boron and calcium fertilization

    Microsoft Academic Search

    O. I. Oyewole; E. A. Aduayi

    1992-01-01

    A local variety of tomato (Lycopersicon esculentum, Ife plum cv. 51691) was grown in soil culture for 5 months and treated with B at concentrations of 0, 1, 2, 4, 8, and 16 ppm as H3BO3, and Ca at 0, 40, 80, and 160 ppm as Ca(OH)2. A significantly positive correlation was established between organic matter and water ? soluble

  19. Biodegradation of monohalogenated alkanes by soil NH 3 -oxidizing bacteria

    Microsoft Academic Search

    K. N. Duddleston; D. J. Arp; P. J. Bottomley

    2002-01-01

    .   Although cooxidative biodegradation of monohalogenated hydrocarbons has been well studied in the model NH3-oxidizing bacterium, Nitrosomonas europaea, virtually no information exists about cooxidation of these compounds by native populations of NH3-oxidizing bacteria. To address this subject, nitrifying activity was stimulated to 125–400 nmol NO3\\u000a – produced g–1 soil h–1 by first incubating a Ca(OH)2-amended, silt loam soil (pH 7.0±0.2) at field

  20. Preparation of diatomite\\/Ca(OH) 2 sorbents and modelling their sulphation reaction

    Microsoft Academic Search

    Nilgün Karatepe; Nilüfer Erdo?an; Ay?egül Ersoy-Meriçboyu; Sadriye Küçükbayrak

    2004-01-01

    Mixtures of Ca(OH)2 and diatomite were hydrated at different conditions to produce reactive SO2 sorbents. Two different hydration techniques were used; namely, atmospheric and pressure hydration. The effect of the hydration temperature, time and diatomite\\/Ca(OH)2 weight ratio on the physical properties of the activated sorbents were investigated. In atmospheric hydration, it was found that increasing the temperature and hydration time

  1. Lime treatment of agricultural residues to improve rumen digestibility

    Microsoft Academic Search

    Jagruti Gandi; Mark T. Holtzapple; Alexis Ferrer; F. Michael Byers; Nancy D. Turner; Murlidhar Nagwani; Sushien Chang

    1997-01-01

    Bagasse, bajra (african millet, Pennisetum typhoideum), jowar (indian millet, Sorghum vulgare) and tobacco stalks were treated with lime to increase the rate and extent of dry matter digestibility. All four materials were treated with 10 g Ca(OH)2\\/100 g dry biomass at 100°C for 1 to 2 h. The residual calcium in the biomass after lime treatment and washing was 1.5

  2. Highly active catalysts from inexpensive raw materials for coal gasification

    Microsoft Academic Search

    Yasuo Ohtsuka; Kenji Asami

    1997-01-01

    The present review article focuses on novel methods of converting inexpensive raw materials to active catalysts for low-temperature coal gasification, which can produce clean fuels and valuable feedstock with high thermal efficiency. Precipitation methods using NH3, urea, and Ca(OH)2 make it possible to prepare active, Cl-free iron catalysts on brown coals from an aqueous solution of FeCl3 as the major

  3. Silica-Enhanced Sorbents for Dry Injection Removal of SO2 from Flue Gas

    Microsoft Academic Search

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

    1988-01-01

    Novel silica-enhanced lime sorbents were tested in a bench-scale sand-bed reactor for their potential for SO2 removal from flue gas. Reactor conditions were 64°C (147°F), relative humidity of 60 percent [corresponding to an approach to saturation temperature of 10°C (18°F)], and inlet SO2 concentration of 500 or 1000 ppm. The sorbents were prepared by pressure hydration of CaO or Ca(OH)2

  4. Intra-canal calcium hydroxide removal by two rotary systems: A comparative study

    PubMed Central

    Dadresanfar, Bahare; Abbas, Fateme Mashhadi; Bashbaghi, Hamide; Miri, Shima Sadat; Ghorbani, Farshid

    2015-01-01

    Aim: The presence of calcium hydroxide (Ca(OH)2) in the root canal interferes with the apical root canal sealing and may result in periapical lesions in the long run. The present study was aimed to compare the efficacy of two rotary systems of Race and Mtwo in the removal of Ca (OH)2 aqueous-based from distobuccal canals of human maxillary molars. Materials and Methods: A total of 44 distobuccal root canals of human maxillary molars were randomly distributed into two groups of 20 canals each and two control groups. Specimens in each group were instrumented with similar master apical rotary (MAR) and flexible files according to the manufacture's guidelines. The Ca (OH)2 paste was placed in canals using # 20 lentulo and radiographs were taken from the two dimensions. The roots were incubated for 1 week at 37°C and 100% humidity and Ca (OH)2 was removed from canals by MAR, afterward. Then, the roots were longitudinally split in halves by diamond disk and chisel without entering the root canals. Photos were taken from the canals’ walls by a stereomicroscope with × 10 magnification. Next, according to a defined scoring system, photos were scored by four endodontists, so that scores 1 and 2 (nonvisible remnants or scattered remnants of Ca(OH)2) were considered as acceptable and scores 3 and 4 (distinct mass or densely-packed mass of Ca(OH)2) were regarded as nonacceptable. Results: The obtained findings indicated that in coronal, middle, and apical portions of the root canal, 45, 60, and 65% of Mtwo specimens and 40, 50, and 55% of specimens prepared by the Race system acquired an acceptable score (1 and 2), respectively. Moreover, the results showed no significant difference between the two groups (P > 0.05). Conclusions: Both Mtwo and Race rotary systems with acceptable removal efficiency (score 1 and 2) were similarly able to remove Ca(OH)2 PMID:26069416

  5. 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

    Akihiko Hashimoto

    1992-01-01

    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,

  6. Enhancement of reactivity in surfactant-modified sorbents for sulfur dioxide control

    Microsoft Academic Search

    David A. Kirchgessner; Wojciech Jozewicz

    1989-01-01

    Injection of calcium-based sorbents into the post-flame zone of utility boilers is capable of achieving sulfur dioxide (SOâ) 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 modify Ca(OH)â by adding calcium lignosulfonate with the water of hydration have succeeded in enhancing its effectiveness. The particle

  7. Changes in mass transfer, thermal and physicochemical properties during nixtamalization of corn with and without agitation at different temperatures

    Microsoft Academic Search

    M. G. Ruiz-Gutiérrez; A. Quintero-Ramos; C. O. Meléndez-Pizarro; D. Lardizábal-Gutiérrez; J. Barnard; R. Márquez-Melendez; R. Talamás-Abbud

    2010-01-01

    White dent corn was nixtamalized in a Ca(OH)2 [1.2% (w\\/v)] solution, at a 1:3corn\\/water ratio, at 70, 80, 90 and 100°C for 1h, with and without mechanical agitation. After cooking the nixtamalized grains were steeped for 48h. During cooking, kinetics of soluble and suspended solids and total sugar were determined, while that in the grain was determined the pericarp removed.

  8. Well-posedness of a moving two-reaction-strips problem modeling

    E-print Network

    Eindhoven, Technische Universiteit

    CO2 in unsaturated cement-based porous materials (concrete). The main issue is that CO2 diffusion. The reduced chemistry of the process is CO2(g aq) + Ca(OH)2(s aq) H2O - CaCO3(aq s) + H2O. (1) We referWell-posedness of a moving two-reaction-strips problem modeling chemical corrosion of porous media

  9. EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science

    E-print Network

    Eindhoven, Technische Universiteit

    + products. (1.1) For instance, the natural carbonation of stone follows the mechanism (1.1), where A1 := CO2(g), A2 := CO2(aq), and A3 := Ca(OH)2(aq), while the product of reac- tion is in this case CaCO3(aq engineering, e.g. in chemical corrosion scenarios as reported in [10, 11, 12]. This reaction

  10. Extraction of Ca(OH), from Portland Cement and 3CaO.Si0, Pastes

    Microsoft Academic Search

    Vangipuram S. Ramachandran; Gary M. Polomark

    1982-01-01

    A procedure for extracting free lime from mature pastes of Portland cement and tricalcium silicate is described. It involves exposure of thin discs of paste to an aqueous solution of Ca(OH)2 in such a way that the concentration of the solution remains in the range 9.5-12 mmol CaO dm-3 throughout the extraction period. Calcium hydroxide remaining in the solid is

  11. CONSUMPTION OF SIMULATED ACID MINE WATER BY SHEEP

    Microsoft Academic Search

    D. J. Horvath

    2010-01-01

    Water consumption by sheep in 48-h periods was measured in three replicated experiments. Intake was expressed as ml, kg body weight-'73-d-1 and treatments were compared with intake of tap water or distilled water in no-choice situations. Neutralizing two acid mine drainage (AMD) polluted waters having pH values of 2.4 and 2.8, with Ca(OH) 2 did not make either as acceptable

  12. The effect of soil pH manipulation on chemical properties of an agricultural soil from northern Idaho

    Microsoft Academic Search

    S. Mohebbi; R. L. Mahler

    1988-01-01

    Selected chemical properties of an artificially acidified agricultural soil from northern Idaho were evaluated in a laboratory study. Elemental S and Ca(OH)2were used to manipulate the soil pH of a Latahco silt loam (fine?silty, mixed, frigid Argiaquic Xeric Argialboll), which had an initial pH of 5.7. A 100 day incubation period resulted in a soil pH manipulation range of 3.3

  13. Hydrogen production from coal by separating carbon dioxide during gasification

    Microsoft Academic Search

    Shiying Lin; Michiaki Harada; Yoshizo Suzuki; Hiroyuki Hatano

    2002-01-01

    Hydrogen generation during the reaction of a coal\\/CaO mixture with high pressure steam was investigated using a flow-type reactor. Coal, CaO and CO reactions with steam, and CO2 absorption by Ca(OH)2 or CaO occurred simultaneously in the experiment. It was found that H2 was the primary resultant gas, comprising about 85% of the reaction products. CO2 was fixed into CaCO3

  14. Estimation of the permeability of silica fume cement concrete

    Microsoft Academic Search

    Ha-Won Song; Seung-Woo Pack; Sang-Hyeok Nam; Jong-Chul Jang; Velu Saraswathy

    2010-01-01

    Deterioration and durability of concrete structures mainly depend on permeability of concrete. Silica fume (SF) as a mineral admixture for high performance concrete produces more discontinues and impermeable pore structure in concrete. The higher permeability reductions with silica fume are due to pore size refinement and matrix densification, reduction in content of Ca(OH)2 and cement paste-aggregate interfacial refinement. During the

  15. PRETREATMENT OF EMPTY PALM FRUIT BUNCH FOR LIGNIN DEGRADATION

    Microsoft Academic Search

    MAILIN MISSON; ROSLINDAWATI HARON; MOHD FADHZIR AHMAD KAMARODDIN; AISHAH SAIDINA

    The potential of three chemical pretreatment methods for lignin degradation of empty palm fruit bunch (EPFB) was investigated. In method 1, sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) bases were exclusively used as degradation agents. In the second method, hydrogen peroxide (H2O2) was simultaneously added with the base while the third method H2O2 was consecutively added into the EPFB-base mixtures

  16. Mass transfer of reactive crystallization in synthesizing calcite nanocrystal

    Microsoft Academic Search

    Rong-yi Lin; Jia-yun Zhang; Yuan-qiang Bai

    2006-01-01

    An experimental study on the mass transfer and reactive crystallization of calcite nanocrystal was carried out in a Na5P3O10–Ca(OH)2–CO2–H2O multiphase system. According to the two-film theory and the two-steps crystal growth model, the kinetic characteristics in the system were investigated by the rate-comparison of the calcium hydroxyl dissolution, carbon dioxide absorption and calcium carbonate precipitation. The result indicated that the

  17. The influence of different substrate pH values on the performance of a downflow anaerobic fixed bed reactor treating a petrochemical effluent

    Microsoft Academic Search

    L. H. Nel; T. J. Britz

    1986-01-01

    Summary Neutralizing requirements for the anaerobic treatment of an acidic petrochemical effluent in a downflow anaerobic fixed bed reactor were examined. Neutralization (pH 6.0 with NaOH) of the effluent prior to digestion resulted in a Na+ concentration of over 3 g\\/l which was detrimental. Decreasing the Na+ concentration and subsequent replacement of NaOH by a mixture of Ca(OH)2, NaOH and

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

    Microsoft Academic Search

    Edward W. Jennings; Daniel J. Schell

    2011-01-01

    Dilute-acid pretreatment of lignocellulosic biomass enhances the ability of enzymes to hydrolyze cellulose to glucose, but produces many toxic compounds that inhibit fermentation of sugars to ethanol. The objective of this study was to compare the effectiveness of treating hydrolysate liquor with Ca(OH)2 and NH4OH for improving ethanol yields. Corn stover was pretreated in a pilot-scale reactor and then the

  19. Characterisation of cement pastes by inverse gas chromatography

    Microsoft Academic Search

    Victor Oliva; Béchir Mrabet; Maria Inês Baeta Neves; Mohamed M. Chehimi; Karim Benzarti

    2002-01-01

    Two cement pastes, commonly used in concrete formulations, were characterised by IGC at 35–80°C before and after coating with an epoxy resin and a hardener. The cements are mixtures of hydrates in various proportions, such as calcium silicate hydrate (CaO–SiO2–H2O) and calcium hydroxide Ca(OH)2. Apolar and polar probes were used to determine the dispersive and acid–base characteristics of the cement

  20. Bioconversion of water-hyacinth ( Eichhornia crassipes) hemicellulose acid hydrolysate to motor fuel ethanol by xylose–fermenting yeast

    Microsoft Academic Search

    J. N. Nigam

    2002-01-01

    Water-hyacinth (Eichhornia crassipes) hemicellulose acid hydrolysate has been utilized as a substrate for ethanol production using Pichia stipitis NRRL Y-7124. Hydrolysate fermentability was considerable improved by boiling, and overliming up to pH 10.0 with solid Ca(OH)2 in combination with sodium sulfite. The percent total sugar utilized and ethanol yield (Yp\\/s) for the untreated hydrolysate were 20.15±0.17% and 0.19±0.003gpgs?1, respectively, compared

  1. Portlandite consumption in metakaolin cement pastes and mortars

    Microsoft Academic Search

    S. Wild; J. M. Khatib

    1997-01-01

    Cement mortars and pastes containing 0, 5, 10 and 15% replacement of cement with metakaolin and with a waterbinder (wb) ratio of 0.55 have been moist cured for periods from 3 to 365 days. The Portlandite content at different ages has been determined by thermogravimetric analysis and this has been related to changes in relative strength. Ca(OH)2 in mortars was

  2. Leaching of both calcium hydroxide and CSH from cement paste: Modeling the mechanical behavior

    Microsoft Academic Search

    Christophe Carde; Raoul François; Jean-Michel Torrenti

    1996-01-01

    This paper deals with the effect of the leaching process of cement based materials on their mechanical properties. This process induces mainly a total leaching of Ca(OH)2 and a progressive decalcification of C-S-H which leads to a gradient of CS ratio in the leaching zone. In a previous work, we venture the hypothesis that the dissolution of calcium hydroxide was

  3. Reversible chemical reactions for energy storage in a large-scale heat utility

    Microsoft Academic Search

    R. G. Nix; P. W. R. G. Bergeron; R. E. West

    1982-01-01

    This paper describes a study of the feasibility of using either Ca(OH)2 or CH4-CO2 reaction systems for long-duration storage in a central receiver, solar energy facility. The system is required to operate 262 MW(t) (8.95 x 10 to the 8th Btu\\/h) as 4.14-MPa (600-psig), 400 C (750 F) superheated steam, with usage split evenly among 10 users clustered in an

  4. The hydration characteristics when C 2S is present in MSWI fly ash slag

    Microsoft Academic Search

    K. S. Wang; K. L. Lin; T. Y. Lee; B. Y. Tzeng

    2004-01-01

    This paper reports on an investigation of the hydration characteristics when C2S is present in municipal solid waste incinerator (MSWI) slag. The results can be summarized as follows: thermogravimetric analysis (TGA) observations show lower amounts of CSH and Ca(OH)2 in samples where C2S is incorporated into MSWI slag, possibly due to the partial replacement (20–40%) of the mineral constituents by

  5. The hydration characteristics of MSWI fly ash slag present in C 3S

    Microsoft Academic Search

    K. L. Lin; K. S. Wang; T. Y. Lee; B. Y. Tzeng

    2003-01-01

    This paper reports on an investigation of the hydration characteristics of C3S and the mixing of C3S with municipal solid waste incinerator (MSWI) fly ash slag. The results can be summarized as follows: TGA observations show lower amounts of CSH and Ca(OH)2 in samples that incorporated MSWI slag into C3S, possibly due to the partial replacement of the C3S by

  6. Effects of antibacterial capping agents on dental pulps of monkeys mechanically exposed to oral microflora.

    PubMed

    Yoshiba, K; Yoshiba, N; Iwaku, M

    1995-01-01

    The effects of antibacterial drugs on bacterially contaminated dental pulps were investigated in monkeys. Class V buccal cavities with pulpal exposures were prepared and then left open to the oral environment for 24 h. The exposed pulps were capped with alpha-tricalcium phosphate (alpha-TCP) containing a mixture of antibacterial drugs. Either alpha-TCP or Ca(OH)2 was used as a control. Pulpal responses were histologically evaluated after 4 wk. Those teeth capped with alpha-TCP alone showed total pulp necrosis and bacterial growth within the pulp chamber. By contrast, the pulps capped with alpha-TCP containing mixed antibacterial drugs remained almost normal without any necrotic layer, but showed persistent absorbing response to capping materials and no signs of hard tissue barrier formation. In teeth capped with Ca(OH)2, a hard tissue barrier was formed below the exposure site, with a wide loss of pulp tissue. No inflammation was seen under the barrier. These results indicate that mixed antibacterial drugs added to alpha-TCP effectively disinfected pulpal lesions, without destroying any of the sound pulp tissue. However, hard tissue barrier formation was delayed by this mixture as compared with Ca(OH)2. PMID:7714429

  7. Continuous precipitation of calcium carbonate using sonochemical reactor.

    PubMed

    Shirsath, S R; Sonawane, S H; Saini, D R; Pandit, A B

    2015-05-01

    The continuous production of calcium carbonate (CaCO3) by precipitation method at room temperature was carried out in a stirred reactor under ultrasonic environment and was compared with the conventional stirring method. The effect of various operating parameters such as Ca(OH)2 slurry concentration, CO2 flow rate and Ca(OH)2 slurry flow rate on the particle size of CaCO3 was investigated. The calcium carbonate particles were characterized by Fourier transform infrared (FTIR), wide angle X-ray diffraction (WXRD) and particle size. The morphology was studied by using scanning electron microscopic (SEM) images. The particle size obtained in the presence of ultrasonic environment was found to be smaller as compared to conventional stirring method. The particle size is found to be reduced with an increase in the concentrations of Ca(OH)2 and increased with increasing CO2 flow rate for both the methods. The slurry flow rate had a major effect on the particle size and the particle size decreased with increased slurry flow rate. Only calcite phase of CaCO3 was predominantly present as confirmed by the characterization techniques for both the preparation methods. In most of the cases rhombohedral calcite particles were observed. PMID:25534035

  8. Removal of boron from wastewater by the hydroxyapatite formation reaction using acceleration effect of ammonia.

    PubMed

    Yoshikawa, Eishi; Sasaki, Atsushi; Endo, Masatoshi

    2012-10-30

    The mechanism was discussed for the removal of boron by the hydroxyapatite (HAp) formation reaction using Ca(OH)(2) and (NH(4))(2)HPO(4) in room temperature. Time required to remove boron was 20 min by adding Ca(OH)(2) and (NH(4))(2)HPO(4) for the remaining boron to below 1mg/L. The removal rate of boron was controlled by the HAp precipitate formation and the presence of ammonia. From the XRD patterns and SEM images, HAp could be confirmed in the precipitate product. The reaction between borate ions and calcium hydroxide was accelerated by dehydration with ammonia; the borate-calcium hydroxide compound coprecipitated with resulting HAp. Although the removal of boron decreased in the presence of sulfate, phosphate, and aluminum, these effects could be prevented by adding excess Ca(OH)(2). Interference of fluoride ions was eliminated by adding Al(3+). Sodium alpha-olefin sulfonate was the most effective coagulant for HAp precipitation. The proposed boron removal method has several advantages about treating time and ability of boron removal. The method was successfully applied to the real hot spring wastewater. PMID:22981286

  9. Comparison of Seven Chemical Pretreatments of Corn Straw for Improving Methane Yield by Anaerobic Digestion

    PubMed Central

    Song, Zilin; GaiheYang; Liu, Xiaofeng; Yan, Zhiying; Yuan, Yuexiang; Liao, Yinzhang

    2014-01-01

    Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS ?1 in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost. PMID:24695485

  10. Influence of flue gas cleaning system on the energetic efficiency and on the economic performance of a WTE plant.

    PubMed

    Poggio, A; Grieco, E

    2010-07-01

    Gas cleaning systems of MSW (Municipal Solid Waste) incinerators are characterised by the process employed to remove acid gases. The commonly used technologies for acid gas removal are: (1) dry treatment with Ca(OH)(2) or (2) with NaHCO(3), (3) semi-dry process with Ca(OH)(2) and (4) wet scrubbing. In some recent plants beside a wet cleaning system, a dry neutralization with Ca(OH)(2) is used. The goal is to reduce the amount of acid to be removed in the wet treatment and the liquid effluents produced. The influence of these different technologies on the electrical efficiency was investigated by a detailed simulation of a WTE (Waste To Energy) plant with a capacity of about 100,000 t/y of MSW. The effects of the different gas cleaning systems on electrical efficiency were significant. The difference of efficiency between the most advantageous technology, which is dry treatment with NaHCO(3), and the least advantageous technology which is semi-dry treatment, is about 0.8%. A simple economic analysis showed that the few advantages of dry technologies can often be lost if the costs of chemicals and the disposal of products are considered. PMID:19822412

  11. Effect of a calcium-silicate-based restorative cement on pulp repair.

    PubMed

    Tran, X V; Gorin, C; Willig, C; Baroukh, B; Pellat, B; Decup, F; Opsahl Vital, S; Chaussain, C; Boukpessi, T

    2012-12-01

    In cases of pulp injury, capping materials are used to enhance tertiary dentin formation; Ca(OH)(2) and MTA are the current gold standards. The aim of this study was to evaluate the capacity of a new calcium-silicate-based restorative cement to induce pulp healing in a rat pulp injury model. For that purpose, cavities with mechanical pulp exposure were prepared on maxillary first molars of 27 six-week-old male rats, and damaged pulps were capped with either the new calcium-silicate-based restorative cement (Biodentine), MTA, or Ca(OH)(2). Cavities were sealed with glass-ionomer cement, and the repair process was assessed at several time-points. At day 7, our results showed that both the evaluated cement and MTA induced cell proliferation and formation of mineralization foci, which were strongly positive for osteopontin. At longer time-points, we observed the formation of a homogeneous dentin bridge at the injury site, secreted by cells displaying an odontoblastic phenotype. In contrast, the reparative tissue induced by Ca(OH)(2) showed porous organization, suggesting a reparative process different from those induced by calcium silicate cements. Analysis of these data suggests that the evaluated cement can be used for direct pulp-capping. PMID:22983409

  12. Susceptibility of Enterococcus faecalis biofilm to antibiotics and calcium hydroxide.

    PubMed

    Chai, Wen L; Hamimah, Hassan; Cheng, Soo C; Sallam, Atiya A; Abdullah, Mariam

    2007-06-01

    The purpose of this study was to investigate the antimicrobial efficacy of six groups of antibiotics and calcium hydroxide against Enterococcus faecalis biofilm in a membrane filter model. Two-day-old E. faecalis (ATCC 29212) biofilm was exposed to ampicillin, co-trimoxazole, erythr omycin, oxytetracycline, vancomycin, vancomycin followed by gentamicin, Ca(OH)(2), and phosphate-buffered saline (control). After 1 h of exposure, the antimicrobial activity was neutralized by washing each disc five times in PBS, and then the colony-forming units of the remaining viable bacteria on each disc were counted. The results revealed that only erythromycin, oxytetracycline and Ca(OH)2 showed 100% biofilm kill. An ANOVA with a Bonferroni post hoc test (P < 0.05) detected significant differences among the test agents, except in the ampicillin group versus the co-trimoxazole group. It is concluded that erythromycin, oxytetracycline and Ca(OH)2 are 100% effective in eliminating E. faecalis biofilm, whereas ampicillin, co-trimoxazole, vancomycin, and vancomycin followed by gentamicin are ineffective. PMID:17634730

  13. Synthesis of proton conducting mesoporous materials and composite membranes for high temperature proton exchange membrane (PEM) fuel cells

    NASA Astrophysics Data System (ADS)

    Feng, Fangxia

    Tungstosilicate mesoporous materials (WMM) were synthesized using the ionic surfactant cetyltrimethylammonium bromide (C16H33N +(CH3)3Br- CTMABr) and non-ionic surfactants, including C12H25(OCH2CH 2)10OH (Brij 22, C12EO10OH), C 16H33(OCH2CH2)10OH (Brij 56, C16EO10OH), and C18H37(OCH 2CH2)10OH (Brij 76, C18EO10OH). The proton conductivities were measured by AC impedance spectroscopy. Using CTMABr, the highest W/Si ratio achieved for the molecular sieve product was 0.03. The conductivity ranged from 0.5 to 2.2 x 10-2 S/cm, where the highest conductivity was observed with the H3PO 4 based preparation. Non-ionic surfactants produced materials with a W/Si ratio as high as 0.05 without any dense WO3 impurities. These samples showed thicker pore walls (39A), higher thermal stability, and higher proton conductivity (4.0 x 10-2 S/cm). The WMMs were also employed to make a composite membrane with linear polyethyleneimine (PEI), 3-glycidoxypropyltrimethoxysilane (GLYMO), bis(trifluoromethanesulfonyl)imide (HTFSI). At 100°C and 100% relative humidity, the composite membrane with 30 wt.% calcined (at 500°C) WMM showed the highest conductivity of 6.1 x 10-2 S/cm. At 130°C and 20% relative humidity, the highest conductivity of 6.4 x 10-3 S/cm was obtained for the composite membrane with 30 wt.% as-synthesized WMM. Transparent free-standing mesoporous silica (MS) films were synthesized from a system of TMOS-Brij-Acid-H2O. The non-ionic surfactants used included Brij 22 (Cl2EO10OH), Brij 56 (C16EO 10OH), and Brij 76 (C18EO10OH). The acids used include HCl, H3PO4, and CF3SO3H. The effect of synthesis parameters on the synthesis and the proton conductivity of mesoporous silica were investigated. The Brij 56/CF3SO 3H based product showed the highest conductivity of 6.5 x 10 -2 S/cm at room temperature. Composite was prepared by combing TMOS, Brij surfactant, acid (HCl, H3PO4, or CF 3SO3H), N-[3-(trimethoxysilyl)propyl]-ethylenediamine (EDATMS), 3-glycidoxypropylmethoxysilane (GLYMO), and bis(trifluoromethanesulfonyl)imide (HTFSI). The effect of TMOS/template content and the acid on the conductivity as well as H2/O2 performance were investigated. The results indicated that the incorporation of TMOs/surfactant/acid could increase the proton conductivity and the fuel cell performance. Sulfonated silica/heteropolyacid (HPA) composite membranes were investigated for high temperature proton exchange membrane (PEM) fuel cells. HPAs included tungstosilicic acid (WSA) and tungstophosphoric acid (WPA). The influence of the HPA type, and HPA content on the proton conductivity and fuel cell performance was investigated. (Abstract shortened by UMI.)

  14. Studies of Equilibrium Solid Solutions in Ionic Lattices Systems: KMnO4&sngbnd;KClO4&sngbnd;H2O and NH4Cl&sngbnd;MnCl2&sngbnd;H2O

    Microsoft Academic Search

    Alexander L. Greenberg; George H. Walden

    1940-01-01

    1. The systems, potassium permanganate-potassium perchlorate-water and ammonium chloride-manganous chloride-water, have been studied at equilibrium conditions by phase rule and x-ray diffraction methods. 2. The system potassium permanganate-potassium perchlorate-water yields a continuous series of solid solutions having orthorhombic crystal symmetry. For these, the components of which are of similar crystal and chemical structure and of identical valence type, Vegard's additivity

  15. Phase relations in the system NaCl-KCl-H2O II: Differential thermal analysis of the halite liquidus in the NaCl-H2O binary above 450°c

    USGS Publications Warehouse

    Gunter, W.D.; Chou, I.-Ming; Girsperger, Sven

    1983-01-01

    The solubility of halite can be expressed as a function of the mole-fractional-based activity of NaCl in the liquid phase (L) in temperature (T, °K) and pressure (P, bars) In  Our liquidus data (based on 10 compositions) above 500 bars for these brines were combined with this equation to generate activity coefficients of NaCl which were fit within their experimental uncertainties to the following one parameter Margules equation In . Concentrated solutions of NaCl show negative deviations from ideality which rapidly increase in magnitude with decreasing XNaCl.

  16. 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

    Revesz, Kinga M.; Landwehr, Jurate Maciunas; Keybl, Jaroslav Edward

    2001-01-01

    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.

  17. Development of an E-H2O2/TiO2 photoelectrocatalytic oxidation system for water and wastewater treatment.

    PubMed

    Li, X Z; Liu, H S

    2005-06-15

    In this study, an innovative E-H2O2/TiO2 (E-H2O2 = electrogenerated hydrogen peroxide) photoelectrocatalytic (PEC) oxidation system was successfully developed for water and wastewater treatment. A TiO2/Ti mesh electrode was applied in this photoreactor as the anode to conduct PEC oxidation, and a reticulated vitreous carbon (RVC) electrode was used as the cathode to electrogenerate hydrogen peroxide simultaneously. The TiO2/Ti mesh electrode was prepared with a modified anodic oxidation process in a quadrielectrolyte (H2SO4-H3PO4-H2O2-HF) solution. The crystal structure, surface morphology, and film thickness of the TiO2/Ti mesh electrode were characterized by X-ray diffraction and scanning electron microscopy. The analytical results showed that a honeycomb-type anatase film with a thickness of 5 microm was formed. Photocatalytic oxidation (PC) and PEC oxidation of 2,4,6-trichlorophenol (TCP) in an aqueous solution were performed under various experimental conditions. Experimental results showed that the TiO2/Ti electrode, anodized in the H2SO4-H3PO4-H2O2-HF solution, had higher photocatalytic activity than the TiO2/Ti electrode anodized in the H2SO4 solution. It was found that the maximum applied potential would be around 2.5 V, corresponding to an optimum applied current density of 50 microA cm(-2) under UV-A illumination. The experiments confirmed that the E-H2O2 on the RVC electrode can significantly enhance the PEC oxidation of TCP in aqueous solution. The rate of TCP degradation in such an E-H2O2-assisted TiO2 PEC reaction was 5.0 times that of the TiO2 PC reaction and 2.3 times that of the TiO2 PEC reaction. The variation of pH during the E-H2O2-assisted TiO2 PEC reaction, affected by individual reactions, was also investigated. It was found that pH was well maintained during the TCP degradation in such an E-H2O2/TiO2 reaction system. This is beneficial to TCP degradation in an aqueous solution. PMID:16047800

  18. New solvent systems for gradient counter-current chromatography in separation of betanin and its derivatives from processed Beta vulgaris L. juice.

    PubMed

    Spórna-Kucab, Aneta; Garrard, Ian; Ignatova, Svetlana; Wybraniec, S?awomir

    2015-02-01

    Betalains, natural plant pigments, are beneficial compounds due to their antioxidant and possible chemoprotective properties. A mixture of betalains: betanin/isobetanin, decarboxybetanins and neobetanin from processed red beet roots (Beta vulgaris L.) juice was separated in food-grade, gradient solvent systems using high-performance counter-current chromatography (HPCCC). The decarboxylated and dehydrogenated betanins were obtained by thermal degradation of betanin/isobetanin from processed B. vulgaris L. juice under mild conditions. Two solvent systems (differing in their composition by phosphoric acid and ethanol volume gradient) consisting of BuOH-EtOH-NaClsolution-H2O-H3PO4 (v/v/v/v/v, 1300:200-1000:1300:700:2.5-10) in the 'tail-to-head' mode were run. The flow rate of the mobile phase (organic phase) was 1.0 or 2.0 ml/min and the column rotation speed was 1,600 rpm (20°C). The retention of the solvent system stationary phase (aqueous phase) was ca. 80%. The system with the acid and ethanol volume gradient consisting of BuOH-EtOH-NaClsolution-H2O-H3PO4 (v/v/v/v/v, 1300:200-240:1300:700:2.5-4.5) pumped at 2.0 ml/min was the most effective for a separation of betanin/isobetanin, 17-decarboxy-betanin/-isobetanin, 2-decarboxy-betanin/-isobetanin, 2,17-bidecarboxy-betanin/-isobetanin pairs as well as neobetanin. The pigments were detected by LC-DAD and LC-MS. The results are crucial in the application of completely food-grade solvent systems in separation of food-grade compounds as well, and the systems can possibly be extended to other ionizable and polar compounds with potential health benefits. In particular, the method is applicable for the isolation and purification of betalains present in such rich sources as B. vulgaris L. roots as well as cacti fruits and Amaranthaceae flowering plants due to modification possibilities of the solvent systems polarity. PMID:25595533

  19. ?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

    Revesz, Kinga M.; Landwehr, Jurate M.

    2002-01-01

    A new method was developed to analyze the stable carbon and oxygen isotope ratios of small samples (400?±?20?µg) 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 ‰, 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 further 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. 

  20. Fabrication of geometric sapphire shaped InGaN/Al2O3 (S) LED scribed by using wet chemical etching

    NASA Astrophysics Data System (ADS)

    Kawan, Anil; Yu, S. J.; Park, Hwa Jin; Seo, Ju-Ok; Yoon, Seok-Beom

    2014-02-01

    The wet chemical etching method for etching V-grooves into sapphire substrates is used as scribing technique, and a geometric sapphire shaped InGaN/Al2O3 (S) light-emitting diode (LED) chip is fabricated. The V-groove is formed on the backside of a 150-µ-thick sapphire substrate by wet etching in a 3H2SO4:1H3PO4 chemical solution. The fabricated wet scribed geometric sapphire shaped LED exhibits a 15.86% enhancement in the light output power at 60-mA compared to the laser-stealth-scribed conventional rectangular LED. In addition, a ray-tracing simulation using "Light Tools" is performed on shaped geometric sapphire samples to investigate the enhancement of the light extracted from the substrate. The enhancement of the light output power for the wetscribed geometric sapphire shaped LED is thought to be due to the elimination of thermal damage and to an increase in light extraction from geometric sapphire shaped structure.

  1. Surface characteristics of TiN/ZrN coated nanotubular structure on the Ti-35Ta-xHf alloy for bio-implant applications

    NASA Astrophysics Data System (ADS)

    Moon, Byung-Hak; Choe, Han-Cheol; Brantley, William A.

    2012-01-01

    In this study, we investigated the surface characteristics of the TiN/ZrN-coated nanotubular structure on Ti-35Ta-xHf ternary alloys for bio-implant applications. These ternary alloys contained from 3 wt.% to 15 wt.% Hf contents and were manufactured in an arc-melting furnace. The Ti-35Ta-xHf alloys were heat treated in Ar atmosphere at 1000 °C for 24 h, followed by water quenching. Formation of the nanotubular structure was achieved by an electrochemical method in 1 M H3PO4 electrolytes containing 0.8 wt.% NaF. The TiN coating and ZrN coating were subsequently prepared by DC-sputtering on the nanotubular surface. Microstructures and nanotubular morphology of the alloys were examined by FE-SEM, EDX and XRD. The microstructure showed a duplex (??? + ?) phase structure. Traces of martensite disappeared with increasing Hf content, and the Ti-35Nb-15Hf alloy had an entirely equiaxed structure of ? phase. This research has shown that highly ordered, high aspect ratio, and nanotubular morphology surface oxide layers can be formed on the ternary titanium alloys by anodization. The TiN and ZrN coatings formed on the nanotubular surfaces were uniform and stable. The top of the nanotube layers was uniformly covered with the ZrN film compared to the TiN film when the Ti-35Ta-xHf alloys had high Hf content.

  2. Phosphorus-31 NMR studies of E. coli ribosomes.

    PubMed Central

    Tritton, T R; Armitage, I M

    1978-01-01

    Phosphorus-31 nuclear magnetic resonance spectra, relaxation times and nuclear Overhauser (NOE) enhancement have been measured for E. coli ribosomes, subunits and rRNA. NOE and T1 experiments reveal that the phosphorus relaxation in this organelle is largely dipolar in origin. Moreover these results imply the presence of internal motion within the RNA chain with a correlation time of about 3-5 x 10(-9) sec. In all cases the predominant resonance is centered at about -1.5 ppm (relative to 85% H3PO4) as expected for a phosphodiester linkage where there is a large degree of double helix. The linewidth narrows by about a factor of four when the ribosomal proteins are removed indicating a substantial immobilization of the RNA when it is assembled into the ribosome. In addition to the phosphodiester resonance, ribosomes also reveal one or two narrower resonances shifted to low field by 1-4 ppm. Based on the observation that these resonances show a pH dependent chemical shift, we assign them to phosphate monoesters i.e. terminal 3' or 5' phosphate groups. These terminal phosphates are due to short oligomers of RNA derived from the terminus of the chain. PMID:31604

  3. Microbial fuel cell enables phosphate recovery from digested sewage sludge as struvite.

    PubMed

    Fischer, Fabian; Bastian, Christèle; Happe, Manuel; Mabillard, Eric; Schmidt, Nicolas

    2011-05-01

    Orthophosphate was mobilized from iron phosphate (FePO(4)) contained in digested sewage sludge by microbial fuel cell power. FePO(4) was reduced through electrons and protons obtained from metabolic activity of Escherichia coli. The process yielded up to 82% or 600 mg/l. Optical emission spectroscopy was used for phosphate dosage. (31)P NMR showed a singlet at ?(p)=3.72 ppm indicating that orthophosphate (H(3)PO(4), HPO(4)(-), HPO(4)(2-) and PO(4)(3-)) was recovered. The phosphate containing supernatant solution was reacted with stoichiometric amounts of MgCl(2) and NH(4)OH to precipitate struvite (MgNH(4)PO(4)·6H(2)O). The crystalline fertilizer was analyzed by scanning electron microscopy comprising elemental analysis, revealing a composition accuracy of ? 90% and the absence of any toxic metals such as As, Cd, Pb, or Cr. The phosphate extraction is also a means to reduce the volume of digested sewage sludge while increasing the heat of combustion. This study represents a concept for sustainable decentralized phosphate recycling. PMID:21411312

  4. Ultrasensitive determination of DNA sequences by flow injection chemiluminescence using silver ions as labels.

    PubMed

    Zheng, Lichun; Liu, Xiuhui; Zhou, Min; Ma, Yongjun; Wu, Guofan; Lu, Xiaoquan

    2014-10-27

    We presented a new strategy for ultrasensitive detection of DNA sequences based on the novel detection probe which was labeled with Ag(+) using metallothionein (MT) as a bridge. The assay relied on a sandwich-type DNA hybridization in which the DNA targets were first hybridized to the captured oligonucleotide probes immobilized on Fe3O4@Au composite magnetic nanoparticles (MNPs), and then the Ag(+)-modified detection probes were used to monitor the presence of the specific DNA targets. After being anchored on the hybrids, Ag(+) was released down through acidic treatment and sensitively determined by a coupling flow injection-chemiluminescent reaction system (Ag(+)-Mn(2+)-K2S2O8-H3PO4-luminol) (FI-CL). The experiment results showed that the CL intensities increased linearly with the concentrations of DNA targets in the range from 10 to 500 pmol L(-1) with a detection limit of 3.3 pmol L(-1). The high sensitivity in this work may be ascribed to the high molar ratio of Ag(+)-MT, the sensitive determination of Ag(+) by the coupling FI-CL reaction system and the perfect magnetic separation based on Fe3O4@Au composite MNPs. Moreover, the proposed strategy exhibited excellent selectivity against the mismatched DNA sequences and could be applied to real samples analysis. PMID:25263118

  5. Silver nanoparticle-based ultrasensitive chemiluminescent detection of DNA hybridization and single-nucleotide polymorphisms.

    PubMed

    Liu, Cheng-Hui; Li, Zheng-Ping; Du, Bao-An; Duan, Xin-Rui; Wang, Yu-Cong

    2006-06-01

    A new nanoparticle-based chemiluminescent (CL) method has been developed for the ultrasensitive detection of DNA hybridization. The assay relies on a sandwich-type DNA hybridization in which the DNA targets are first hybridized to the captured oligonucleotide probes immobilized on polystyrene microwells and then the silver nanoparticles modified with alkylthiol-capped oligonucleotides are used as probes to monitor the presence of the specific target DNA. After being anchored on the hybrids, silver nanoparticles are dissolved to Ag+ in HNO3 solution and sensitively determined by a coupling CL reaction system (Ag+-Mn2+-K2S2O8-H3PO4-luminol). The combination of the remarkable sensitivity of the CL method with the large number of Ag+ released from each hybrid allows the detection of specific sequence DNA targets at levels as low as 5 fM. The sensitivity increases 6 orders of magnitude greater than that of the gold nanoparticle-based colorimetric method and is comparable to that of surface-enhanced Raman spectroscopy, which is one of the most sensitive detection approaches available to the nanoparticle-based detection for DNA hybridization. Moreover, the perfectly complementary DNA targets and the single-base mismatched DNA strands can be evidently differentiated through controlling the temperature, which indicates that the proposed CL assay offers great promise for single-nucleotide polymorphism analysis. PMID:16737231

  6. 31P NMR chemical shielding tensors of diethyl [5,6-dichloro-1,3-benzodioxol-(2)] phosphonate

    NASA Astrophysics Data System (ADS)

    Rohonczy, J.; Ermark, F.; Haeberlen, U.; Klose, G.; Schulz, M.

    1991-05-01

    The 31P NMR chemical-shift tensors of diethyl [5,6-dicholoro-1,3-benzodioxol-(2)] phosphonate were measured in a single crystal. A crystal symmetry of P1 in contrast to P 1- claimed by earlier X-ray studies was found. The principal values of the 31P NMR shielding tensors ?(A) and ?(B), or relative to 85% H 3PO 4, are (A) ? 11 = -90.6, ? 22 = -37.8 and ? 33 = 106.2 ppm, and (B) ? 11 = -89.6, ? 22 = 38.3 and ? 33 = 104.3 ppm. The principal directions corresponding to ? 22 and ? 33 lie in the pseudo-mirror planes spanned by the O?P?C7 molecular fragments. The most shielded directions are almost parallel to the P?O bonds. The centrosymmetry of the two molecules in the unit cells is violated by a small rotation about the ? axis of one molecule with respect to the other.

  7. Carbon molecular sieves from carbon cloth: Influence of the chemical impregnant on gas separation properties

    NASA Astrophysics Data System (ADS)

    Rodríguez-Blanco, G.; Giraldo, L.; Moreno-Piraján, J. C.

    2010-06-01

    Carbon materials with molecular sieve properties (CMS) were prepared by pyrolysis of cotton fabrics by chemical activation procedures. To evaluate the changes in the chemical and textural properties, the impregnants AlCl 3, ZnCl 2 and H 3PO 4 were used at 1123 K. The materials were characterized using adsorption of nitrogen and carbon dioxide, TPD, and immersion calorimetry in C 6H 6. Adsorption kinetics of O 2, N 2, CO 2, CH 4, C 3H 8 and C 3H 6 were measured in all the prepared materials to determine their behaviour as molecular sieves. The results confirm that the chemical used as impregnant has a significant effect on the resulting CMS separation properties. All materials exhibit microporosity and low oxygen surface group contents; however, the sample impregnated with zinc chloride, with an immersion enthalpy value of 66.4 J g -1 in benzene, exhibits the best performance in the separation of CH 4-CO 2 and C 3H 8-C 3H 6 at 273 K.

  8. Nanocomposite Membranes based on Polybenzimidazole and ZrO2 for High-Temperature Proton Exchange Membrane Fuel Cells.

    PubMed

    Nawn, Graeme; Pace, Giuseppe; Lavina, Sandra; Vezzù, Keti; Negro, Enrico; Bertasi, Federico; Polizzi, Stefano; Di Noto, Vito

    2015-04-24

    Owing to the numerous benefits obtained when operating proton exchange membrane fuel cells at elevated temperature (>100?°C), the development of thermally stable proton exchange membranes that demonstrate conductivity under anhydrous conditions remains a significant goal for fuel cell technology. This paper presents composite membranes consisting of poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI4N) impregnated with a ZrO2 nanofiller of varying content (ranging from 0 to 22?wt?%). The structure-property relationships of the acid-doped and undoped composite membranes have been studied using thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, wide-angle X-ray scattering, infrared spectroscopy, and broadband electrical spectroscopy. Results indicate that the level of nanofiller has a significant effect on the membrane properties. From 0 to 8?wt?%, the acid uptake as well as the thermal and mechanical properties of the membrane increase. As the nanofiller level is increased from 8 to 22?wt?% the opposite effect is observed. At 185?°C, the ionic conductivity of [PBI4N(ZrO2 )0.231 ](H3 PO4 )13 is found to be 1.04×10(-1) ?S?cm(-1) . This renders membranes of this type promising candidates for use in high-temperature proton exchange membrane fuel cells. PMID:25801848

  9. Immobilization of Rose Waste Biomass for Uptake of Pb(II) from Aqueous Solutions

    PubMed Central

    Ansari, Tariq Mahmood; Hanif, Muhammad Asif; Mahmood, Abida; Ijaz, Uzma; Khan, Muhammad Aslam; Nadeem, Raziya; Ali, Muhammad

    2011-01-01

    Rosa centifolia and Rosa gruss an teplitz distillation waste biomass was immobilized using sodium alginate for Pb(II) uptake from aqueous solutions under varied experimental conditions. The maximum Pb(II) adsorption occurred at pH 5. Immobilized rose waste biomasses were modified physically and chemically to enhance Pb(II) removal. The Langmuir sorption isotherm and pseudo-second-order kinetic models fitted well to the adsorption data of Pb(II) by immobilized Rosa centifolia and Rosa gruss an teplitz. The adsorbed metal is recovered by treating immobilized biomass with different chemical reagents (H2SO4, HCl and H3PO4) and maximum Pb(II) recovered when treated with sulphuric acid (95.67%). The presence of cometals Na, Ca(II), Al(III), Cr(III), Cr(VI), and Cu(II), reduced Pb(II) adsorption on Rosa centifolia and Rosa gruss an teplitz waste biomass. It can be concluded from the results of the present study that rose waste can be effectively used for the uptake of Pb(II) from aqueous streams. PMID:21350666

  10. Development of advanced Kocite electrocatalysts for phosphoric acid fuel cells. Final technical report, September 1979-December 1980

    SciTech Connect

    Welsh, L.S.; Leyerle, R.W.; Scarlata, D.S.; Vanek, M.A.

    1981-01-01

    These improved electrocatalysts should demonstrate a larger initial catalytic metal surface area, and a better catalytic metal surface area retention during fuel cell operation than present state-of-the-art phosphoric acid electrocatalysts. Kocite electrocatalysts impregnated with platinum and platinum-vanadium alloys were tested. The Kocite electrocatalysts were aged in electrodes potentiostated in H3PO4 half cells, and were then analyzed for catalytic metals surface area retention. Compared with the state-of-the-art platinum electrocatalysts, as represented by a standard Kocite electrocatalyst, the Kocite electrocatalysts impregnated by the techniques used in this study has a better initial platinum surface area. This initial surface area difference appeared to be maintained when the catalysts are aged at 700 mV, but was not maintained when the catalysts were aged at 800 mV. Variations of the alumina substrate and of the post-treatment of the leached Kocite catalyst support did not produce any catalysts with better platinum surface area retention than the standard catalyst. Alloying of vanadium with the platinum did produce Kocite electrocatalysts which maintained their alloy surface area better than the standard catalyst maintained its platinum surface area.

  11. Extraction behavior of metallic contaminants and soil constituents from contaminated soils.

    PubMed

    Tokunaga, S; Park, S W; Ulmanu, M

    2005-06-01

    With an aim of developing an effective remediation technology for soils contaminated by heavy metals and metalloids, the extraction behavior of metallic contaminants as well as those of soil constituents was studied on a laboratory scale. Three contaminated soils collected from a former metal recycling plant were examined. These three soils were found to be contaminated by As, Cu, Pb, Sb, Se and Zn as compared to the non-contaminated soil. The pH-dependent extraction behavior of various elements from the soils was measured in a wide pH range and categorized into three groups. Hydrochloric acid (HCl), H2SO4, H3PO4, HNO3, sodium citrate, sodium tartrate, disodium dihydrogen ethylenediaminetetraacetate and diethylenetriaminepentaacetic acid were evaluated as extractants for removing contaminants from the soils. Extraction behavior of the soil constituents was also studied. The efficiency of the extraction was evaluated by the Japanese content and leaching tests. The stabilization of Pb remaining in the soil after the extraction process was conducted by the addition of iron(III) and calcium chloride. PMID:16035660

  12. Stability of the anodic growth porous tungsten oxide in different solutions

    NASA Astrophysics Data System (ADS)

    Chai, Y.; Yam, F. K.; Hassan, Z.

    2015-05-01

    This article presents the study of the stability of the anodic growth porous tungsten oxide (WO3) film in different solutions. As-anodized films are relatively stable in acidic electrolytes like sulphuric acid (H2SO4), hydrochloric acid (HCl) but not in oxalic acid. In higher pH solution, rate of dissolution of the WO3 film is higher. Annealing at 400 °C for 2 h transform the as-grown sample from amorphous phase to the crystalline phase and this significantly improve the stability of the film in high pH solution. Photocurrent measurements reveal that there is no significant difference of the electrolyte used (0.5 M H2SO4, 0.33 M H3PO4, 0.1 M sodium sulfate (Na2SO4)) on the photocurrent. As-annealed films exhibit good stablility for the long photoelectrochemical (PEC) measurements (1700 s) in 0.5 M H2SO4 and 0.1 M Na2SO4. There is no effect on the photocurrent for the variation of the concentration of the acidic solution (H2SO4). However, lower photocurrent was obtained as the concentration of Na2SO4 was increased.

  13. Osteoconductivity and Hydrophilicity of TiO2 Coatings on Ti Substrates Prepared by Different Oxidizing Processes

    PubMed Central

    Yamamoto, Dai; Kawai, Ikki; Kuroda, Kensuke; Ichino, Ryoichi; Okido, Masazumi; Seki, Azusa

    2012-01-01

    Various techniques for forming TiO2 coatings on Ti have been investigated for the improvement of the osteoconductivity of Ti implants. However, it is not clear how the oxidizing process affects this osteoconductivity. In this study, TiO2 coatings were prepared using the following three processes: anodizing in 0.1 M H3PO4 or 0.1 M NaOH aqueous solution; thermal oxidation at 673?K for 2 h in air; and a two-step process of anodizing followed by thermal oxidation. The oxide coatings were evaluated using SEM, XRD, and XPS. The water contact angle on the TiO2 coatings was measured as a surface property. The osteoconductivity of these samples was evaluated by measuring the contact ratio of formed hard tissue on the implanted samples (defined as the RB-I value) after 14?d implantation in rats' tibias. Anatase was formed by anodizing and rutile by thermal oxidation, but the difference in the TiO2 crystal structure did not influence the osteoconductivity. Anodized TiO2 coatings were hydrophilic, but thermally oxidized TiO2 coatings were less hydrophilic than anodized TiO2 coatings because they lacked in surface OH groups. The TiO2 coating process using anodizing without thermal oxidation gave effective improvement of the osteoconductivity of Ti samples. PMID:23316128

  14. Adsorption of naphthenic acids on high surface area activated carbons.

    PubMed

    Iranmanesh, Sobhan; Harding, Thomas; Abedi, Jalal; Seyedeyn-Azad, Fakhry; Layzell, David B

    2014-01-01

    In oil sands mining extraction, water is an essential component; however, the processed water becomes contaminated through contact with the bitumen at high temperature, and a portion of it cannot be recycled and ends up in tailing ponds. The removal of naphthenic acids (NAs) from tailing pond water is crucial, as they are corrosive and toxic and provide a substrate for microbial activity that can give rise to methane, which is a potent greenhouse gas. In this study, the conversion of sawdust into an activated carbon (AC) that could be used to remove NAs from tailings water was studied. After producing biochar from sawdust by a slow-pyrolysis process, the biochar was physically activated using carbon dioxide (CO2) over a range of temperatures or prior to producing biochar, and the sawdust was chemically activated using phosphoric acid (H3PO4). The physically activated carbon had a lower surface area per gram than the chemically activated carbon. The physically produced ACs had a lower surface area per gram than chemically produced AC. In the adsorption tests with NAs, up to 35 mg of NAs was removed from the water per gram of AC. The chemically treated ACs showed better uptake, which can be attributed to its higher surface area and increased mesopore size when compared with the physically treated AC. Both the chemically produced and physically produced AC provided better uptake than the commercially AC. PMID:24766592

  15. Presence of phosphorus in Nephila clavipes dragline silk.

    PubMed

    Michal, C A; Simmons, A H; Chew, B G; Zax, D B; Jelinski, L W

    1996-01-01

    Solid-state 31P-NMR of Nephila clavipes dragline silk indicates the presence of phosphorus in at least two chemically distinct environments. Amino acid analyses of acid-hydrolyzed silk confirm the presence of phosphotyrosine as one of the phosphorus-containing components. The unusual chemical shift (18.9 ppm downfield from 85% H3PO4), proton chemical shift, and acid lability of a second component suggest that it is part of a strained five-membered cyclic phosphate that might be found on a beta-D-ribose. The five-membered cyclic phosphate is not removed from the silk fibers by exhaustive aqueous extraction. It is absent in nascent silk fibroin from the glands, suggesting that its formation is part of the fiber processing that occurs in the ducts leading to the spinnerets. High-resolution NMR spectra of silk dissolved in propionic acid/12 N HCl (50:50 v/v) show five phosphorus sites assigned to phosphorylated tyrosine residues, phosphorylated serine residues, inorganic phosphate, and two hydrolysis products of the cyclic phosphate compound. The observed posttranslational phosphorylation may be important in the processing and modulation of the physical properties of dragline silk. PMID:8770226

  16. Radiocarbon dating of archaeological samples (sambaqui) using CO(2) absorption and liquid scintillation spectrometry of low background radiation.

    PubMed

    Mendonça, Maria Lúcia T G; Godoy, José M; da Cruz, Rosana P; Perez, Rhoneds A R

    2006-01-01

    Sambaqui means, in the Tupi language, a hill of shells. The sambaquis are archaeological sites with remains of pre-historical Brazilian occupation. Since the sambaqui sites in the Rio de Janeiro state region are older than 10,000 years, the applicability of CO(2) absorption on Carbo-sorb and (14)C determination by counting on a low background liquid scintillation counter was tested. In the present work, sambaqui shells were treated with H(3)PO(4) in a closed vessel in order to generate CO(2). The produced CO(2) was absorbed on Carbo-sorb. On saturation about 0.6g of carbon, as CO(2), was mixed with commercial liquid scintillation cocktail (Permafluor), and the (14)C activity determined by counting on a low background counter, Packard Tricarb 3170 TR/SL, for a period of 1000 mins to enable detection of a radiocarbon age of 22,400 BP. But only samples with ages up to 3500 BP were submitted to the method because the samples had been collected in the municipality of Guapimirim, in archaeological sambaqui-type sites belonging to this age range. The same samples were sent to the (14)C Laboratory of the Centro de Energia Nuclear na Agricultura (CENA/USP) where similar results were obtained. PMID:16630675

  17. a-SiC:H films used as photoelectrodes in a hybrid, thin-film silicon photoelectrochemical (PEC) cell for progress toward 10% solar-to hydrogen efficiency

    NASA Astrophysics Data System (ADS)

    Zhu, Feng; Hu, Jian; Kunrath, Augusto; Matulionis, Ilvydas; Marsen, Bjorn; Cole, Brian; Miller, Eric; Madan, Arun

    2007-09-01

    In this paper we describe the fabrication of amorphous SiC:H materials and using them as photoelectrodes in photoelectrochemical cells (PEC). With the increase of CH 4 flow (in SiH4 gas mixture) during growth, the bandgap, Eg, increases from ~ 1.8eV to ~2.0eV, while the photoconductivity decreases from ~10 -5 S/cm to ~10 -8 S/cm. These high-quality a-SiC:H materials with Eg of 2.0eV included into a solar cell configuration led to a conversion efficiency,?~7% on textured Asahi U type SnO II coated substrates, with the i-layer thickness of ~300nm. For a reduced i-layer thickness of ~100 nm, a current density, J sc ~8.45mA/cm2 has been achieved, Immersing the a-SiC:H(p)/a-SiC:H(i) structure in 0.33M H 3PO 4 electrolytes, produced a photocurrent of ~7mA/cm2. With a further optimization we expect that the photocurrent could exceed 9mA/cm2. With the use of this configuration substrate/silicon tandem device (a-Si/a-Si or a- Si/nc-Si)/a-SiC:H(p)/a-SiC:H(i), it may therefore be possible to increase the solar-to-hydrogen (STH) efficiencies to beyond 10%.

  18. Constituents and antimicrobial properties of blue honeysuckle: a novel source for phenolic antioxidants.

    PubMed

    Palíková, Irena; Heinrich, Jan; Bednár, Petr; Marhol, Petr; Kren, Vladimír; Cvak, Ladislav; Valentová, Katerina; R?zicka, Filip; Holá, Veronika; Kolár, Milan; Simánek, Vilím; Ulrichová, Jitka

    2008-12-24

    The fruit of Lonicera caerulea L. (blue honeysuckle; Caprifoliaceae) and its phenolic fraction were analyzed for nutrients and micronutrients. The phenolic fraction was prepared from berries percolated with 0.1% H3PO4 and SPE using Sepabeads SP207. The sugar and lipid content was analyzed by HPLC and GC-MS. The total content of anthocyanins was determined using the pH differential absorbance method and aliphatic acids by capillary electrophoresis. MicroLC-MS/MS was used for determination of cyanidin-3-glucoside (the predominant anthocyanin), 3,5-diglucoside, and 3-rutinoside, paeonidin-3-glucoside, 3,5-diglucoside, and 3-rutinoside, delphinidin-3-glucoside and 3-rutinoside, pelargonidin-3-glucoside, 3,5-diglucoside, and 3-rutinoside, quercetin, its 3-glucoside, and 3-rutinoside, epicatechin, protocatechuic, gentisic, ellagic, ferulic, caffeic, chlorogenic, and coumaric acids. The phenolic fraction displayed Folin-Ciocalteu reagent reducing (335 +/- 15 microg of gallic acid equivalent/mg) and DPPH and superoxide scavenging activity (IC50 12.1 +/- 0.1 and 115.5 +/- 6.4 microg/mL) and inhibited rat liver microsome peroxidation (IC50 160 +/- 20 microg/mL). The freeze-dried fruit and its phenolic fraction reduced the biofilm formation and adhesion to the artificial surface of Candida parapsilosis, Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, and Streptococcus mutans. PMID:19112647

  19. Nanotube nucleation phenomena on Ti-25Ta-xZr alloys for implants using ATO technique.

    PubMed

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

    2014-10-01

    The purpose of this study was to investigate nanotube nucleation phenomena on the Ti-25Ta-xZr alloys for implant materials, using an anodic titanium oxide (ATO) technique. Ti-25Ta-(0 wt.%-15 wt.%) Zr alloys were prepared using a vacuum arc-melting furnace. The Ti-25Ta-xZr alloys were then homogenized for 12 hr at 1000 degrees C, followed by water quenching. Formation of the nanotubular oxide surface structure was achieved initially on the Ti-25Ta-xZr alloys by anodization in a 1 M H3PO4 electrolyte containing 0.8 wt.% NaF at room temperature, using a potentiostat. After the first formation of the nanotubes was achieved, this initial nanotube layer was eliminated, and further anodization was carried out repeatedly. The microstructure, phase transformation, and morphology of nanotubular Ti-25Ta-xZr alloys and the process of nanotube growth using this ATO method were analyzed by X-ray diffraction, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. Microstructures of the Ti-25Ta-xZr alloys changed from ?" phase to ? phase. Nanotubes formed with the ATO technique had pit-like top holes, with thinner walls and lower contact angle, compared to the initially formed nanotubes. PMID:25942827

  20. Surface characteristics of HA coating and micro-pore formation on the Ti-25Nb-xHf alloys for dental materials.

    PubMed

    Kim, Sung-Hwan; Jeong, Yong-Hoon; Choe, Han-Cheol

    2014-10-01

    Micro-pore formation on titanium surface can increase the adhesion strength with increment of surface area, and hydroxyapatite is effective coating materials as a main chemical constituent of bone tissue for biomedical field. The aim of this study was to investigate the surface characteristics of HA coating and micro-pore formation on the Ti-25Nb-xHf alloys for dental materials. The Ti-25Nb-xHf alloys consisted of (0 and 7) wt.% Hf contents which were manufactured by vacuum arc-melting furnace. The homogenization was performed at 1000 degrees C for 12 h and water quenched. Anodization was carried out using an electrochemical method in 1 M H3PO4 electrolyte. The HA films were deposited by plasma sputtering method. The microstructures of alloys were transformed from ?" phase to ? phase by addition of Hf element, and needle-like structures were translated to an equiaxed structure as Hf content increased. The peaks of anatase and rutile showed on the anodized surface of these alloys. The number of micro-pore decreased, with presence of Hf content increased, whereas size of micro-pore increased. Anodized surface was covered with HA particles at surface and in holes. Contact angle value of HA coating on anodized surface was lower than that of non-coating surface. PMID:25942859