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Sample records for strongly alkaline solutions

  1. Mixed-potential Behavior of Nanostructured RuO2 Sensing Electrode of Water Quality Sensors in Strong Alkaline Solutions at a Temperature Range of 9-30° C

    Science.gov (United States)

    Zhuiykov, Serge

    2009-05-01

    Mixed-potential behavior of the water quality monitoring sensors using nanostructured RuO2 sensing electrode (SE) has been observed in strong alkaline solutions at dissolved oxygen (DO) measurements in the temperature range of 9-30° C. This behavior indicated that a Faradaic oxygen reduction reaction becomes not only a one-electron process, which is typical for DO measurements at a neutral pH, but rather multi-step process with superoxide oxygen ions (O2-), OH- and RuO42- ions involvement. The DO sensing characteristics were examined in the pH range of 2.0-13.0. The measured emf at strong alkaline solutions is a mixed potential from the reactions involved RuO42- and OH- ions and DO. Impedance spectroscopy was employed for confirmation the mixed-potential behavior of the sensor. It was also found during experiments that OH- ions influence the response/recovery rate of the SE reactions as the pH of water increases.

  2. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  3. Progress of research on the influence of alkaline cation and alkaline solution on bentonite properties

    International Nuclear Information System (INIS)

    Ye Weimin; Zheng Zhenji; Chen Bao; Chen Yonggui

    2011-01-01

    Based on the previous laboratory studies and numerical simulation on bentonite in alkaline environments, the effects of alkaline cation and alkaline solution on mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite are emphasized in this paper, temperature, pH values and concentration are discussed as main affecting factors. When bentonite is exposed to alkaline cation or alkaline solution, microstructure of bentonite will be changed due to the dissolution of montmorillonite and the formation of secondary minerals, which results in the decrease of swelling pressure. The amount of the reduction of swelling pressure depends on the concentration of alkaline solution. Temperature, polyvalent cation, salinity and concentration are the main factors affecting hydraulic properties of bentonite under alkaline conditions. Therefore, future research should focus on the mechanism of coupling effects of weak alkaline solutions on the mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite under different temperatures and different pH values. (authors)

  4. Solubility of pllutonium in alkaline salt solutions

    International Nuclear Information System (INIS)

    Hobbs, D.T.; Edwards, T.B.

    1993-01-01

    Plutonium solubility data from several studies have been evaluated. For each data set, a predictive model has been developed where appropriate. In addition, a statistical model and corresponding prediction intervals for plutonium solubility as a quadratic function of the hydroxide concentration have been developed. Because of the wide range of solution compositions, the solubility of plutonium can vary by as much as three orders of magnitude for any given hydroxide concentration and still remain within the prediction interval. Any nuclear safety assessments that depend on the maximum amount of plutonium dissolved in alkaline salt solutions should use concentrations at least as great as the upper prediction limits developed in this study. To increase the confidence in the prediction model, it is recommended that additional solubility tests be conducted at low hydroxide concentrations and with all of the other solution components involved. To validate the model for application to actual waste solutions, it is recommended that the plutonium solubilities in actual waste solutions be determined and compared to the values predicted by the quadratic model

  5. Metal adsorbent for alkaline etching aqua solutions of Si wafer

    International Nuclear Information System (INIS)

    Tamada, Masao; Ueki, Yuji; Seko, Noriaki; Takeda, Toshihide; Kawano, Shin-ichi

    2012-01-01

    High performance adsorbent is expected to be synthesized for the removal of Ni and Cu ions from strong alkaline solution used in the surface etching process of Si wafer. Fibrous adsorbent was synthesized by radiation-induce emulsion graft polymerization onto polyethylene nonwoven fabric and subsequent amination. The reaction condition was optimized using 30 L reaction vessel and nonwoven fabric, 0.3 m width and 18 m long. The resulting fibrous adsorbent was evaluated by 48 wt% NaOH and KOH contaminated with Ni and Cu ions, respectively. The concentration levels of Ni and Cu ions was reduced to less than 1 μg/kg (ppb) at the flow rate of 10 h −1 in space velocity. The life of adsorbent was 30 times higher than that of the commercialized resin. This novel adsorbent was commercialized as METOLATE ® since the ability of adsorption is remarkably higher than that of commercial resin used practically in Si wafer processing. - Highlights: ► Adsorbent was synthesized by radiation-induced emulsion graft polymerization. ► Degree of grafting reached 120% at the pre-irradiation of 50 kGy. ► The resulting adsorbent removed Ni and Cu ion in strong alkaline solution. ► Adsorbent was commercialized for filter of Si wafer etchant.

  6. Perturbation of an exact strong gravity solution

    International Nuclear Information System (INIS)

    Baran, S.A.

    1982-10-01

    Perturbations of an exact strong gravity solution are investigated. It is shown, by using the new multipole expansions previously presented, that this exact and static spherically symmetric solution is stable under odd parity perturbations. (author)

  7. Kinetics of the Fading of Phenolphthalein in Alkaline Solution.

    Science.gov (United States)

    Nicholson, Lois

    1989-01-01

    Described is an experiment which illustrates pseudo-first-order kinetics in the fading of a common indicator in an alkaline solution. Included are background information, details of materials used, laboratory procedures, and sample results. (CW)

  8. Micelle formation during extraction of alkali elements from strongly alkaline mediums

    International Nuclear Information System (INIS)

    Apanasenko, V.V.; Reznik, A.M.; Bukin, V.I.; Brodskaya, A.V.

    1988-01-01

    Extraction of potassium, rubidium and cesium by phenol reagents in hydrocarbon solvents from strongly alkakine solutions was considered. Tendency of prepared alkali metal phenolates to form micelles in aqueous and organic phases was revealed. Phenolates tendency to form micelles is dictated mainly by the size and position of hydrocarbon substituent in molecule. It is shown that when micelles form in organic phase, alkali elements can be extracted both according to cation-exchange mechanism and according to micellar one. It is noted that alkai element extraction from strongly alkaline media requires the correct choice of extractant: alkali metal phenolate shouldn't form micelles in aqueous solution. n-Alkyl- and arylphenoldisulfides and polysulfides are most preferable for solvent extraction among considered phenol derivatives

  9. Americium extraction by alkylpyrocatechin from alkaline salt solutions

    International Nuclear Information System (INIS)

    Karalova, Z.K.; Rodionova, L.M.; Myasoedov, B.F.

    1984-01-01

    Effect of iron, aluminium, calcium, and sodium nitrates on americium extraction by 0.1 mol/l DOP solution [4-(α-α dioctylethyl) pyrocatechin] in toluene from a mixture of 2 mol/l NaOH with 0.1 mol/l EDTA has been investigated. It has been shown that americium extraction does not change essen-- tially in the presence of salts that permits to use DOP for Am extraction from alkaline solutions in the presence of outside salts. Verification of the above method of extraction of radioactive isotopes has been carried out. According to the data obtained double extraction provides a preparation of alkaline solutions practically free from radioactive isotopes. DOP application for Am extraction from alkaline salt solutions allows one to carry out repeated Am concentration and separation from accompanying elements. Conditions, under which Fe(3)-Am(3) pair separation coefficient achieves nx10 2 -10 4 , have been found out

  10. Potentiodynamic characteristics of cadmium and silver in alkaline solutions

    International Nuclear Information System (INIS)

    Saidman, S.B.; Vilche, J.R.; Arvia, A.J.; Lopes Teijelo, M.

    1984-01-01

    The potentiodynamic and ellipsometric characteristics of cadmium and silver in alkaline solutions are studied. The phenomenology of both electrodes shows some common features which are interpreted in termo of a complex hydrated oxide anodic film structure resulting from simultaneous electrochemical and chemical reactions. The kinetics of film growth fits the predictions of nucleation and growth models. (C.L.B.) [pt

  11. Analytical solution of strongly nonlinear Duffing oscillators

    OpenAIRE

    El-Naggar, A.M.; Ismail, G.M.

    2016-01-01

    In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance m...

  12. Analytical solution of strongly nonlinear Duffing oscillators

    Directory of Open Access Journals (Sweden)

    A.M. El-Naggar

    2016-06-01

    Full Text Available In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε is defined such that the value of α is always small regardless of the magnitude of the original parameter ε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to α. Approximate solution obtained by the present method is compared with the solution of energy balance method, homotopy perturbation method, global error minimization method and lastly numerical solution. We observe from the results that this method is very simple, easy to apply, and gives a very good accuracy not only for small parameter εbut also for large values of ε.

  13. Electrochemical Behavior of Sulfur in Aqueous Alkaline Solutions

    Science.gov (United States)

    Mamyrbekova, Aigul; Mamitova, A. D.; Mamyrbekova, Aizhan

    2018-03-01

    The kinetics and mechanism of the electrode oxidation-reduction of sulfur on an electrically conductive sulfur-graphite electrode in an alkaline solution was studied by the potentiodynamic method. To examine the mechanism of electrode processes occurring during AC polarization on a sulfur-graphite electrode, the cyclic polarization in both directions and anodic polarization curves were recorded. The kinetic parameters: charge transfer coefficients (α), diffusion coefficients ( D), heterogeneous rate constants of electrode process ( k s), and effective activation energies of the process ( E a) were calculated from the results of polarization measurements. An analysis of the results and calculated kinetic parameters of electrode processes showed that discharge ionization of sulfur in alkaline solutions occurs as a sequence of two stages and is a quasireversible process.

  14. Characterization of palm fibers modified with alkaline solution

    International Nuclear Information System (INIS)

    Sipiao, Bryan L.S.; Goulart, Shane A.G.; Mulinari, Daniella R.; Souza Junior, Fernando G. de

    2011-01-01

    This work had the objective of to study one inexpensive and effective technique that enables the application of natural fibers from the Australian Royal Palm as reinforcement in polymer composites. The fibers treated with alkaline solution were characterized by infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) and had their data compared with the fiber in nature. Data showed that the treatment made on fibers surface was effective. (author)

  15. Enhancing boron rejection in FO using alkaline draw solutions.

    Science.gov (United States)

    Wang, Yi-Ning; Li, Weiyi; Wang, Rong; Tang, Chuyang Y

    2017-07-01

    This study provides a novel method to enhance boron removal in a forward osmosis (FO) process. It utilizes the reverse solute diffusion (RSD) of ions from alkaline draw solutions (DSs) and the concentration polarization of the hydroxyl ions to create a highly alkaline environment near the membrane active surface. The results show that boron rejection can be significantly enhanced by increasing the pH of NaCl DS to 12.5 in the active-layer-facing-feed-solution (AL-FS) orientation. The effect of RSD enhanced boron rejection was further promoted in the presence of concentration polarization (e.g., in the active-layer-facing-draw-solution (AL-DS) orientation). The current study opens a new dimension for controlling contaminant removal by FO using tailored DS chemistry, where the RSD-induced localized water chemistry change is taken advantage in contrast to the conventional method of chemical dosing to the bulk feed water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Perturbation Solutions of the Quintic Duffing Equation with Strong Nonlinearities

    Directory of Open Access Journals (Sweden)

    Mehmet Pakdemirli

    Full Text Available The quintic Duffing equation with strong nonlinearities is considered. Perturbation solutions are constructed using two different techniques: The classical multiple scales method (MS and the newly developed multiple scales Lindstedt Poincare method (MSLP. The validity criteria for admissible solutions are derived. Both approximate solutions are contrasted with the numerical solutions. It is found that MSLP provides compatible solution with the numerical solution for strong nonlinearities whereas MS solution fail to produce physically acceptable solution for large perturbation parameters.

  17. Dissolution rates of amorphous silica in highly alkaline solution

    International Nuclear Information System (INIS)

    Niibori, Yuichi; Tochiyama, Osamu; Kunita, Masahisa; Chida, Tadashi

    2000-01-01

    Cement is an essential materials to construct the subsurface radioactive waste disposal system. However, cementitious materials alter the groundwater pH to highly alkaline condition about 13. To comprehend the effect of such a hyperalkaline condition on the repository surroundings, this study focused on the dissolution rates of amorphous silica at [NaOH]=10 -1 mol·dm -3 . The used samples were three kinds of pure commercial silica and a natural silica scale which was obtained from inside wall of the hot-water pipe of a geothermal power plant. The observed dissolution rates were interpreted with using the model, which assumed that the particle sizes decrease with the progress of dissolution. Moreover, due to the particle size distribution anticipated in the natural silica scale, this analysis assumed it contained particles with various initial diameters. In the results, (1) all pure silica samples and at least 60 wt% of the silica scale showed good agreement of the activation energy of the dissolution in the range of 77 through 88 kJ·mol -1 in the highly alkaline solution, (2) these rate constants were of the order of 10 -8 - 10 -7 mol·m -2 ·s -1 at around 310 K and were definitely larger than those already reported for quartz, (3) the specific surface area based on BET method was revealed to be an important factor to give the main difference in the dissolution rates between the synthetic silica and the natural silica. (author)

  18. Electro-oxidation of methanol on copper in alkaline solution

    International Nuclear Information System (INIS)

    Heli, H.; Jafarian, M.; Mahjani, M.G.; Gobal, F.

    2004-01-01

    The electro-oxidation of methanol on copper in alkaline solutions has been studied by the methods of cyclic voltammetry, quasi-steady state polarization and chronoamperometry. It has been found that in the course of an anodic potential sweep the electro-oxidation of methanol follows the formation of Cu III and is catalysed by this species through a mediated electron transfer mechanism. The reaction also continues in the early stages of the reversed cycle until it is stopped by the prohibitively negative potentials. The process is diffusion controlled and the current-time responses follow Cottrellian behavior. The rate constants, turnover frequency, anodic transfer coefficient and the apparent activation energy of the electro-oxidation reaction are reported

  19. Zinc electrodeposition from alkaline zincate solution by pulsating overpotentials

    Directory of Open Access Journals (Sweden)

    MILOS V. SIMICIC

    2000-09-01

    Full Text Available It is well known that smooth zinc deposits cannot be obtained from alkaline zincate using constant overpotential and current rate. During prolonged metal deposition, spongy and dendritic deposits are formed. It has been shown that the deposits are less agglomerated in the case of square-wave pulsating overpotentials regime than the ones obtained in case of constant overpotential regime. This is explained in a semiquantitative way by two phenomena: selective anodic dissolution during overpotentials “off” period and decreasing diffusion control. These effects is more pronounced at higher pause-to-pulse ratio. Increasing the pause-to-pulse ratio causes a reduction of the ratio between diffusion and activation overpotential, resulting in a more compact deposit. Confirmation of the proposed semiquantitative mathematical model was obtained by zinc electrodeposition onto a copper wire from a 0.1 M zincate solution in 1.0 M KOH at room temperature.

  20. Precipitation of uranium oxide by reduction in alkaline solution

    International Nuclear Information System (INIS)

    Pottier, P.; Claus, J.

    1964-01-01

    In the first part of the report the authors study the reaction mechanism for this reduction which makes it possible to precipitate a hydrated uranium oxide from alkaline uranyl carbonate solutions. The research into the effects of different variables on numerous cycles are then summarized. Optical, X-ray and thermogravimetric examinations then make it possible to predict the properties of this oxide. In the second part the authors carry out calculations for the continuous operation of single cells and cells in series. These calculations give the data required for the construction of 2 cells having capacities of 0.3 and 10 litres. Results obtained from the continuous operation of this latter cell lead to certain conclusions concerning the applicability of this method to the hydrometallurgy of uranium. (authors) [fr

  1. Pt-decorated nanoporous gold for glucose electrooxidation in neutral and alkaline solutions

    Directory of Open Access Journals (Sweden)

    Yan Xiuling

    2011-01-01

    Full Text Available Abstract Exploiting electrocatalysts with high activity for glucose oxidation is of central importance for practical applications such as glucose fuel cell. Pt-decorated nanoporous gold (NPG-Pt, created by depositing a thin layer of Pt on NPG surface, was proposed as an active electrode for glucose electrooxidation in neutral and alkaline solutions. The structure and surface properties of NPG-Pt were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray powder diffraction (XRD, and cyclic voltammetry (CV. The electrocatalytic activity toward glucose oxidation in neutral and alkaline solutions was evaluated, which was found to depend strongly on the surface structure of NPG-Pt. A direct glucose fuel cell (DGFC was performed based on the novel membrane electrode materials. With a low precious metal load of less than 0.3 mg cm-2 Au and 60 μg cm-2 Pt in anode and commercial Pt/C in cathode, the performance of DGFC in alkaline is much better than that in neutral condition.

  2. Recovering lead from cathode ray tube funnel glass by mechano-chemical extraction in alkaline solution.

    Science.gov (United States)

    Zhang, Chenglong; Wang, Jingwei; Bai, Jianfeng; Guan, Jie; Wu, Wenjie; Guo, Cuixiang

    2013-07-01

    This study evaluates the efficiency of lead (Pb) extraction from cathode ray tube (CRT) funnel glass in strongly alkaline solution using mechanical activation in a ball mill as the chemical breakage and defects formed in the inner structures will contribute to the easy dissolution of the activated Pb glass. The combination of mechanical activation and a chemical leaching process in a single operation (mechano-chemical leaching) is more effective than the mechanical activation and subsequent chemical leaching. More than 97% of Pb in the CRT funnel glass can be extracted with a stirring ball mill leaching process in 5 M sodium hydroxide at 70°C. The diameter of the stainless steel balls as the activation medium is 5 mm; the mass ratio of ball to raw materials is 25:1. Pb powder with a purity of 97% can be obtained by electrowinning from the leaching solution. The Pb-depleted solution can be recycled into the leaching step. After Pb is removed, the solid leaching residues can be used for preparation of foam glass. Thus, a novel hydrometallurgical process for recovering Pb from CRT funnel glass in alkaline solution is proposed.

  3. Degradation rates and products of fluticasone propionate in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Tadakazu Tokumura

    2017-10-01

    Full Text Available The apparent degradation rate constant of fluticasone propionate (FLT in 0.1 M NaOH:methanol=1:1 at 37 °C was previously reported to be 0.169±0.003 h−1, and four degradation products (products 1–4 were observed in the solution. The aims of the present study were to assess the degradation rates of FLT in other alkaline solutions and clarify the chemical structures of the four degradation products in order to obtain basic data for designing an enema for inflammatory bowel disease. The apparent degradation rate constants in 0.05 M NaOH and 0.1 M NaOH:CH3CN=1:1 were 0.472±0.013 h−1 and 0.154±0.000 h−1 (n=3, respectively. The chemical structures of products 1–4 in 0.1 M NaOH:methanol=1:1 were revealed by nuclear magnetic resonance (NMR and mass spectrometry data. The chemical structure of products 2 was that the 17-position of the thioester moiety of FLT was substituted by a carboxylic acid. The degradation product in 0.1 M NaOH:CH3CN=1:1 was found to be product 2 based on 1H NMR data. The degradation product in 0.05 M NaOH was considered to be product 2 based on the retention time of HPLC. These results are useful for detecting the degradation products of FLT by enzymes of the intestinal bacterial flora in the large intestine after dosing FLT as an enema.

  4. Actinides in Hanford Tank Waste Simulants: Chemistry of Selected Species in Oxidizing Alkaline Solutions

    International Nuclear Information System (INIS)

    Nash, Kenneth L.; Laszak, Ivan; Borkowski, Marian; Hancock, Melissa; Rao, Linfeng; Reed, Wendy

    2004-01-01

    To enhance removal of selected troublesome nonradioactive matrix elements (P, Cr, Al, S) from the sludges in radioactive waste tanks at the Hanford site, various chemical washing procedures have been evaluated. It is intended that leaching should leave the actinides in the residual sludge phase for direct vitrification. Oxidative treatment with strongly alkaline solutions has emerged as the best approach to accomplishing this feat. However, because the most important actinide ions in the sludge can exist in multiple oxidation states, it is conceivable that changes in actinide oxidation state speciation could interfere with hopes and plans for actinide insolubility. In this presentation, we discuss both the impact of oxidative alkaline leachants on actinide oxidation state speciation and the chemistry of oxidized actinide species in the solution phase. Actinide oxidation does occur during leaching, but the solubility behavior is complex. Mixed ligand complexes may dominate solution phase speciation of actinides under some circumstances. This work was supported by the U.S. Department of Energy, Offices of Science and Waste Management, Environmental Management Science Program under Contract DEAC03- 76SF0098 at Lawrence Berkeley National Laboratory and Contract W-31-109- ENG-38 at Argonne National Laboratory

  5. The electrochemistry of SIMFUEL in dilute alkaline hydrogen peroxide solutions

    Science.gov (United States)

    Goldik, Jon

    The work described in this thesis is a study of the electrochemistry of SIMFUEL (SIMulated nuclear FUEL) in dilute, alkaline hydrogen peroxide solutions. In the first set of experiments, the reaction of H2O 2 on SIMFUEL electrodes was studied electrochemically and under open circuit conditions in 0.1 mol L-1 NaCl solutions at pH 9.8. The composition of the oxidized UO2 surface was determined by X-ray photoelectron spectroscopy. Hydrogen peroxide reduction was found to be catalyzed by the formation of a mixed UIV/UV (UO 2+x) surface layer, but to be blocked by the accumulation of UVI species (UO3· yH2O or adsorbed (UO2)2+) on the electrode surface. The formation of this UVI layer blocks both H2O2 reduction and oxidation, thereby inhibiting the potentially rapid H2O2 decomposition reaction to H2O and O2. Decomposition is found to proceed at a rate controlled by the desorption of the adsorbed (UO2)2+ or reduction of adsorbed O2 species. Reduction of (O2) ads is coupled to the slow oxidative dissolution of UO2 and formation of a corrosion product deposit of UO3· yH2O. In the second series of experiments, the electrochemical reduction of hydrogen peroxide on SIMFUEL was studied using the steady-state polarization technique. Kinetic parameters for the reaction, such as Tafel slopes and reaction orders, were determined. The results were interpreted in terms of a chemical-electrochemical mechanism involving UIV/UV donor-acceptor reduction sites. The large values of the Tafel slopes and the fractional reaction orders with respect to H2O2 can be understood in terms of the potential-dependent surface coverage of active sites, similar to that observed in the reduction of hydrogen peroxide on oxidized copper surfaces. The effects of pH over the range 10-13 were also investigated. The H2O 2 reduction currents were nearly independent of pH in the range 10-11, but were slowed at more alkaline values. The change in pH dependence appears to be related to the acid-base properties

  6. Deuterium Labelling of L-Tyrosine with Raney Alloys in Alkaline Deuterium Oxide Solutions

    OpenAIRE

    Tsuzuki, Hirohisa; Mukumoto, Mamoru; Udagawa, Jun; Mataka, Shuntaro; Tashiro, Masashi

    1997-01-01

    The synthesis of deuteriated L-tyrosines with Raney alloys in alkaline deuterium oxide solutions, involving reductive debromination of brominated L-tyrosines and hydrogen-deuterium (H-D) exchange of L-tyrosines, without causing racemization, is presented.

  7. Decomposition Studies of Triphenylboron, Diphenylborinic Acid and Phenylboric Acid in Aqueous Alkaline Solutions Containing Copper

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.L. [Westinghouse Savannah River Company, AIKEN, SC (United States); Peterson, R. A.

    1997-02-11

    This report documents the copper-catalyzed chemical kinetics of triphenylboron, diphenylborinic acid and phenylboric acid (3PB, 2PB and PBA) in aqueous alkaline solution contained in carbon-steel vessels between 40 and 70 degrees C.

  8. Americium/Lanthanide Separations in Alkaline Solutions for Advanced Nuclear Fuel Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Goff, George S. [Los Alamos National Laboratory; Long, Kristy Marie [Los Alamos National Laboratory; Reilly, Sean D. [Los Alamos National Laboratory; Jarvinen, Gordon D. [Los Alamos National Laboratory; Runde, Wolfgang H. [Los Alamos National Laboratory

    2012-06-11

    Project goals: Can used nuclear fuel be partitioned by dissolution in alkaline aqueous solution to give a solution of uranium, neptunium, plutonium, americium and curium and a filterable solid containing nearly all of the lanthanide fission products and certain other fission products? What is the chemistry of Am/Cm/Ln in oxidative carbonate solutions? Can higher oxidation states of Am be stabilized and exploited? Conclusions: Am(VI) is kinetically stable in 0.5-2.0 M carbonate solutions for hours. Aliquat 336 in toluene has been successfully shown to extract U(VI) and Pu(VI) from carbonate solutions. (Stepanov et al 2011). Higher carbonate concentration gives lower D, SF{sub U/Eu} for = 4 in 1 M K{sub 2}CO{sub 3}. Experiments with Am(VI) were unsuccessful due to reduction by the organics. Multiple sources of reducing organics...more optimization. Reduction experiments of Am(VI) in dodecane/octanol/Aliquat 336 show that after 5 minutes of contact, only 30-40% of the Am(VI) has been reduced. Long enough to perform an extraction. Shorter contact times, lower T, and lower Aliquat 336 concentration still did not result in any significant extraction of Am. Anion exchange experiments using a strong base anion exchanger show uptake of U(VI) with minimal uptake of Nd(III). Experiments with Am(VI) indicate Am sorption with a Kd of 9 (10 minute contact) but sorption mechanism is not yet understood. SF{sub U/Nd} for = 7 and SF{sub U/Eu} for = 19 after 24 hours in 1 M K{sub 2}CO{sub 3}.

  9. Weak and strong solutions for differential equations in Banach spaces

    International Nuclear Information System (INIS)

    Gomaa, A.M.

    2003-01-01

    In this paper we give a generalization to recent results by using weak and strong measures of noncompactness. For f:[0,T]xE→E with E is a Banach space we prove that, under suitable assumptions, the Cauchy problem (fd((P) (ar((r((c(x(t)=f(t,x(t)),))(c(t/in R: =set membership[0,T],))))(r((c(x(0)=x 0 ,))(c()))))))) has at least one weak solution furthermore, with certain conditions, the Cauchy problem (P) has a solution. Next under a generalization of the compactness assumptions, we show that (P) has a solution too

  10. Selective solvation extraction of gold from alkaline cyanide solution by alkyl phosphorus esters

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.D.; Wan, R.Y.; Mooiman, M.B.; Sibrell, P.L.

    1987-01-01

    Research efforts have shown that solvation extraction of gold from alkaline cyanide solution is possible by alkyl phosphorus esters. Both tributyl phosphate (TBP) and dibutyl butyl phosphonate (DBBP) appear to be effective extractants for gold and exhibit high loading capacities exceeding 30 gpl. Selective solvation extraction of gold from alkaline cyanide solution can be achieved with selectivity factors relative to other cyanoanions as high as 1000 under certain circumstances. Variables influencing the selectivity such as ionic strength, temperature, and extractant structure, are discussed in terms of the extraction chemistry, which seems to involve the solvation of a M dot, dot, dot Au(CN)2 ion pair.

  11. Metabolic effect of alkaline additives and guanosine/gluconate in storage solutions for red blood cells.

    Science.gov (United States)

    D'Alessandro, Angelo; Reisz, Julie A; Culp-Hill, Rachel; Korsten, Herbert; van Bruggen, Robin; de Korte, Dirk

    2018-04-06

    Over a century of advancements in the field of additive solutions for red blood cell (RBC) storage has made transfusion therapy a safe and effective practice for millions of recipients worldwide. Still, storage in the blood bank results in the progressive accumulation of metabolic alterations, a phenomenon that is mitigated by storage in novel storage additives, such as alkaline additive solutions. While novel alkaline additive formulations have been proposed, no metabolomics characterization has been performed to date. We performed UHPLC-MS metabolomics analyses of red blood cells stored in SAGM (standard additive in Europe), (PAGGSM), or alkaline additives SOLX, E-SOL 5 and PAG3M for either 1, 21, 35 (end of shelf-life in the Netherlands), or 56 days. Alkaline additives (especially PAG3M) better preserved 2,3-diphosphoglycerate and adenosine triphosphate (ATP). Deaminated purines such as hypoxanthine were predictive of hemolysis and morphological alterations. Guanosine supplementation in PAGGSM and PAG3M fueled ATP generation by feeding into the nonoxidative pentose phosphate pathway via phosphoribolysis. Decreased urate to hypoxanthine ratios were observed in alkaline additives, suggestive of decreased generation of urate and hydrogen peroxide. Despite the many benefits observed in purine and redox metabolism, alkaline additives did not prevent accumulation of free fatty acids and oxidized byproducts, opening a window for future alkaline formulations including (lipophilic) antioxidants. Alkalinization via different strategies (replacement of chloride anions with either high bicarbonate, high citrate/phosphate, or membrane impermeant gluconate) results in different metabolic outcomes, which are superior to current canonical additives in all cases. © 2018 AABB.

  12. Iterative solutions of nonlinear equations with strongly accretive or strongly pseudocontractive maps

    International Nuclear Information System (INIS)

    Chidume, C.E.

    1994-03-01

    Let E be a real q-uniformly smooth Banach space. Suppose T is a strongly pseudo-contractive map with open domain D(T) in E. Suppose further that T has a fixed point in D(T). Under various continuity assumptions on T it is proved that each of the Mann iteration process or the Ishikawa iteration method converges strongly to the unique fixed point of T. Related results deal with iterative solutions of nonlinear operator equations involving strongly accretive maps. Explicit error estimates are also provided. (author). 38 refs

  13. Methylene blue adsorption of GMZ bentonite and the effect of hyper-alkaline solution erosion

    International Nuclear Information System (INIS)

    Chen Bao; Zhang Huixin; Zhu Chunming; Chen Ping

    2012-01-01

    The method of combining the halo method with the spectrometer method, was used to study on the Methylene blue (MB) adsorption of Gaomiaozi (GMZ) bentonite, which had been eroded by hyper-alkaline solution, to investigate the mechanism of the effect of hyper-alkaline pore water on the buffer/backfill properties of GMZ bentonite. Results present, method employed in this article is brief and feasible, and high accuracy; The total specific surface area calculated by the test of MB adsorption is more accurate than the method of ethylene glycol monomethyl ether (EGIVIE). The MB adsorption of samples, which had been eroded by hyper-alkaline solution, decreases with the increase of the concentration of hyper-alkaline solution, and the change law agrees with the variation of the mass percentage of montmorillonite in bentonite tested by X- Ray diffraction (XRD). Therefore, the erosion of hyper-alkaline pore water might dissolve montmorillonite, which is the effective composition of bentonite, and destroy the tetrahedron- octahedron-tetrahedron (T-O-T) structure of montmorillonite, then lead to the decrease of cation exchange capability and the specific surface area of montmorillonite, and the the macroscopic expressions are the decrease of MB adsorption, the swelling potential and the increase of permeability. (authors)

  14. Iterative solution of nonlinear equations with strongly accretive operators

    International Nuclear Information System (INIS)

    Chidume, C.E.

    1991-10-01

    Let E be a real Banach space with a uniformly convex dual, and let K be a nonempty closed convex and bounded subset of E. Suppose T:K→K is a strongly accretive map such that for each f is an element of K the equation Tx=f has a solution in K. It is proved that each of the two well known fixed point iteration methods (the Mann and Ishikawa iteration methods) converges strongly to a solution of the equation Tx=f. Furthermore, our method shows that such a solution is necessarily unique. Explicit error estimates are given. Our results resolve in the affirmative two open problems (J. Math. Anal. Appl. Vol 151(2) (1990), p. 460) and generalize important known results. (author). 32 refs

  15. Epitaxial electrodeposition of ZnO on Au(111) from alkaline solution: exploiting amphoterism in Zn(II).

    Science.gov (United States)

    Limmer, Steven J; Kulp, Elizabeth A; Switzer, Jay A

    2006-12-05

    The amphoteric nature of ZnO is used to produce the material from strongly alkaline solution. The solution pH is lowered globally to produce ZnO powder, and it is lowered locally at a Au(111) surface to produce epitaxial films. ZnO powder is precipitated from a solution of 10 mM Zn(II) in 0.25 M NaOH by simply adding 1 M HNO3 to the solution. For the film electrodeposition, the local pH at the electrode surface is decreased by electrochemically oxidizing the ascorbate dianion. The chemically precipitated ZnO powder grows with a sea urchin-like nanostructure, whereas the electrodeposited films have a columnar structure. ZnO electrodeposited onto a Au(111) single crystal has a ZnO(0001)[1011]//Au(111)[110] orientation relationship.

  16. Electrocatalysts for Hydrogen Evolution in Alkaline Electrolytes: Mechanisms, Challenges, and Prospective Solutions.

    Science.gov (United States)

    Mahmood, Nasir; Yao, Yunduo; Zhang, Jing-Wen; Pan, Lun; Zhang, Xiangwen; Zou, Ji-Jun

    2018-02-01

    Hydrogen evolution reaction (HER) in alkaline medium is currently a point of focus for sustainable development of hydrogen as an alternative clean fuel for various energy systems, but suffers from sluggish reaction kinetics due to additional water dissociation step. So, the state-of-the-art catalysts performing well in acidic media lose considerable catalytic performance in alkaline media. This review summarizes the recent developments to overcome the kinetics issues of alkaline HER, synthesis of materials with modified morphologies, and electronic structures to tune the active sites and their applications as efficient catalysts for HER. It first explains the fundamentals and electrochemistry of HER and then outlines the requirements for an efficient and stable catalyst in alkaline medium. The challenges with alkaline HER and limitation with the electrocatalysts along with prospective solutions are then highlighted. It further describes the synthesis methods of advanced nanostructures based on carbon, noble, and inexpensive metals and their heterogeneous structures. These heterogeneous structures provide some ideal systems for analyzing the role of structure and synergy on alkaline HER catalysis. At the end, it provides the concluding remarks and future perspectives that can be helpful for tuning the catalysts active-sites with improved electrochemical efficiencies in future.

  17. Electrochemical Performance of Low-Carbon Steel in Alkaline Model Solutions Containing Hybrid Aggregates

    NARCIS (Netherlands)

    Koleva, D.A.; Hu, J.; De Wit, J.H.W.; Boshkov, N.; Radeva, T.; Milkova, V.; Van Breugel, K.

    2010-01-01

    This work reports on the electrochemical performance of low-carbon steel electrodes in model alkaline solutions in the presence of 4.9.10-4 g/l hybrid aggregates i.e. cement extract, containing PDADMAC (poly (diallyl, dimethyl ammonium chloride) / PAA (Poly (acrylic acid)/ PDADMAC over a CaO core.

  18. Defect structure of cubic solid solutions of alkaline earth and rare earth fluorides

    NARCIS (Netherlands)

    DenHartog, HW

    1996-01-01

    In this paper we will consider the disorder in some cubic solid solutions consisting of one of the alkaline earth fluorides and one of the rare earth fluorides. This is an attractive group of model materials, because these materials have a rather simple overall cubic structure. We will discuss the

  19. Novel package for inhibition of aluminium corrosion in alkaline solutions

    International Nuclear Information System (INIS)

    Abdel-Gaber, A.M.; Khamis, E.; Abo-Eldahab, H.; Adeel, Sh.

    2010-01-01

    Inhibition of aluminium corrosion in 2 M sodium hydroxide solution by a package composed of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and lupine seed extract has been investigated employing different electrochemical techniques and chemical gasometry measurements. Potentiodynamic polarization curve measurements showed that lupine seed extract controls both the anodic dissolution of aluminium and the hydrogen gas evolved at the cathodic sites of aluminium surface. Nyquist plots showed two capacitive semicircles in the high and low frequency regions separated by an inductive loop at intermediate frequencies. The inductive loop may be explained by the occurrence of adsorbed intermediates on the surface. A proposed equivalent circuit was used to analyse the impedance spectra for aluminium in NaOH solutions. The corrosion inhibition data have been analysed using different isotherms. The results showed excellent agreement between the kinetic-thermodynamic model and Flory-Huggins isotherm. Gasometry measurements showed that the Inhibitive effect of the surfactant increases at a composition around its critical micelle concentration (cmc). The presence of both the surfactant and lupine seed extract did not indicate synergistic action between them. The mode of adsorption of the surfactant molecules corresponding to their structure is also discussed.

  20. Electrochemical Recovery of Sodium Hydroxide from Alkaline Salt Solution

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T. [Westinghouse Savannah River Company, AIKEN, SC (United States); Edwards, T.B.

    1996-10-01

    A statistically designed set of tests determined the effects of current density, temperature, and the concentrations of nitrate/nitrite, hydroxide and aluminate on the recovery of sodium as sodium hydroxide (caustic) from solutions simulating those produced from the Savannah River Site (SRS) In-Tank Precipitation process. These tests included low nitrate and nitrite concentrations which would be produced by electrolytic nitrate/nitrite destruction. The tests used a two compartment electrochemical cell with a Nafion Type 324 ion-exchange membrane. Caustic was successfully recovered from the waste solutions. Evaluation of the testing results indicated that the transport of sodium across the membrane was not significantly affected by any of the varied parameters. The observed variance in the sodium flux is attributed to experimental errors and variations in the performance characteristics of individual pieces of the organic-based Nafion membrane.Additional testing is recommended to determine the maximum current density, to evaluate the chemical durability of the organic membrane as a function of current density and to compare the durability and performance characteristics of the organic-based Nafion membrane with that of other commercially available organic membranes and the inorganic class of membranes under development by Ceramatec and PNNL.

  1. Regulating Water-Reduction Kinetics in Cobalt Phosphide for Enhancing HER Catalytic Activity in Alkaline Solution.

    Science.gov (United States)

    Xu, Kun; Ding, Hui; Zhang, Mengxing; Chen, Min; Hao, Zikai; Zhang, Lidong; Wu, Changzheng; Xie, Yi

    2017-07-01

    Electrochemical water splitting to produce hydrogen renders a promising pathway for renewable energy storage. Considering limited electrocatalysts have good oxygen-evolution reaction (OER) catalytic activity in acid solution while numerous economical materials show excellent OER catalytic performance in alkaline solution, developing new strategies that enhance the alkaline hydrogen-evolution reaction (HER) catalytic activity of cost-effective catalysts is highly desirable for achieving highly efficient overall water splitting. Herein, it is demonstrated that synergistic regulation of water dissociation and optimization of hydrogen adsorption free energy on electrocatalysts can significantly promote alkaline HER catalysis. Using oxygen-incorporated Co 2 P as an example, the synergistic effect brings about 15-fold enhancement of alkaline HER activity. Theory calculations confirm that the water dissociation free energy of Co 2 P decreases significantly after oxygen incorporation, and the hydrogen adsorption free energy can also be optimized simultaneously. The finding suggests the powerful effectiveness of synergetic regulation of water dissociation and optimization of hydrogen adsorption free energy on electrocatalysts for alkaline HER catalysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Passivation behavior of a ferritic stainless steel in concentrated alkaline solutions

    Directory of Open Access Journals (Sweden)

    Arash Fattah-alhosseini

    2015-10-01

    Full Text Available The passivation behavior of AISI 430 ferritic stainless steel was investigated in concentrated alkaline solutions in relation to several test parameters, using electrochemical techniques. Increasing solution pH (varying from 11.5 to 14.0 leads to an increase in the corrosion rate of the alloy. Mott–Schottky analysis revealed that passive films formed on AISI 430 ferritic stainless steel behave as n-type semiconductor and the donor densities increased with pH. Electrochemical impedance spectroscopy (EIS results showed that the reciprocal capacitance of the passive film is directly proportional to its thickness, which decreases with pH increase. The results revealed that for this ferritic stainless steel in concentrated alkaline solutions, decreasing the solution pH offers better conditions for forming passive films with higher protection behavior, due to the growth of a much thicker and less defective film.

  3. Alteration behavior of bentonite barrier of radioactive waste disposal by alkaline solutions. Part 1. Permeability change of compacted bentonite immersed in alkaline solutions

    International Nuclear Information System (INIS)

    Yokoyama, Shingo; Nakamura, Kunihiko

    2010-01-01

    Permeability tests using the compacted bentonites and alkaline solutions were carried out to estimate of alteration behavior and the change of permeability during the alteration reaction. The permeability tests of the compacted bentonites were carried out at 23degC for one week after they were immersed in alkaline solution at 60degC for four weeks (immersing test). After permeability tests, the compacted bentonites were repeatedly tested as the same procedure (i.e. repetition of permeability test and immersing test) at 11 cycles. The compacted bentonites with initial dry density of 1.6 Mg/m 3 were reacted with the different type of the alkaline solutions (deionized water, NaOH (pH=12 and 14), KOH (pH=12 and 14) and Ca(OH) 2 (pH=12)) in each experiments. In the case of deionized water and alkaline solutions of pH12, the mineral compositions of altered bentonite were similar to original bentonite while the exchangeable cations of altered bentonites were changed. No changes of the mineralogical features of montmorillonite in altered bentonites (i.e. illitization, baideritization and increasing of layer charge) were observed in the case of deionized water, pH12-NaOH and pH12-Ca(OH) 2 . The montmorillonite was changed to the illite/smectite interstratified mineral containing about 40% illite like component during the reaction with pH12-KOH. In the case of alkaline solutions with pH14, the component minerals of bentonite (e.g. montmorillonite, quartz and clinoptilolite) were dissolved, consequently secondly minerals (e.g. analcime and phillipsite) were crystallized during experiments. Furthermore, the mineralogical features of montmorillonite were changed as illitization (pH14-KOH), beidellitization (pH14-NaOH and pH14-KOH) and increasing of layer charge (pH14-NaOH and pH14-KOH). No increasing of permeability were observed during the experiment using pH12-NaOH and pH12-Ca(OH) 2 as well as the case of deionized water. In the case of pH12-KOH, the permeability continually

  4. Volumetric determination of hydroxide, aluminate, and carbonate in alkaline solutions of nuclear waste

    International Nuclear Information System (INIS)

    Baumann, E.W.

    1975-06-01

    An integrated procedure was developed for determining OH - , Al(OH) 4 - , and CO 3 2- in alkaline nuclear waste. The free alkali, the hydroxide released when Al(OH) 3 is complexed with oxalate, and the precipitated BaCO 3 were determined by acidimetric titration. With a 50-μl sample, the relative standard deviations were 1 to 2 percent for nonradioactive test solutions and 2 to 5 percent for radioactive process solutions. (U.S.)

  5. Weibull Statistical Analysis on the Mechanical Properties of SiC by Immersion in Acidic and Alkaline Solutions

    International Nuclear Information System (INIS)

    Ahn, Seok-Hwan; Jeong, Sang-Cheol; Nam, Ki-Woo

    2016-01-01

    A Weibull statistical analysis of the mechanical properties of SiC ceramics was carried out by immersion in acidic and alkaline solutions. The heat treatment was carried out at 1373 K. The corrosion of SiC was carried out in acidic and alkaline solutions under KSL1607. The bending strength of corroded crack-healed specimens decreased 47 % and 70 % compared to those of uncorroded specimens in acidic and alkaline solutions, respectively. The corrosion of SiC ceramics is faster in alkaline solution than in acid solution. The scale and shape parameters were evaluated for the as-received and corroded materials, respectively. The shape parameter of the as-received material corroded in acidic and alkaline solutions was significantly more apparent in the acidic solution. Further, the heat-treated material was large in acidic solution but small in alkaline solution. The shape parameters of the as-received and heat-treated materials were smaller in both acidic and alkaline solutions

  6. Individual activity coefficients of single ionic species of alkaline earth halogenides, alkaline earth perchlorates, and uranyl perchlorate at 25 0C in aqueous solutions

    International Nuclear Information System (INIS)

    Ferse, A.

    1981-01-01

    The individual activity coefficients of the single ionic species of alkaline-earth haloides, alkaline earth perchlorates and uranylic perchlorate, resp., at 25 0 C in aqueous solution are calculated and presented up to the concentration of about m = 4 mol/kg. The individual activity coefficients of the alkaline-earth ions pass mostly as a function of the concentration through a steep minimum and decrease from Mg 2+ to Ba 2+ . The individual activity coefficients of the anions pass generally as a function of the concentration through a marked flat minimum, but they increase - the complex perchlorate ions excepted - only a little above 1. (author)

  7. Identification of phase structure of plated zinc alloys based on a linear voltammetry in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Lina V. Petrenko

    2016-12-01

    Full Text Available The purpose of research was the development of new and effective technique of electroplatings phase composition analysis by inversion voltammetric methods. As a result the possibility of the phase composition of the plated zinc-based alloys identification using anodic linear voltammetry in alkaline solutions was shown. The phase composition Zn–(0.27–9.4% Fe alloy electroplated from alkaline zincate solutions was defined based on voltammetry data. As part of the Zn–Fe alloys the phase of hexagonal structure was found which is absent in the equilibrium phase diagram. The ratio of hexagonal crystal lattice axes (c/a and the electron concentration (e/a for this phase are significantly different from the corresponding values for the primary solid solution η. From the analysis of c/a and e/a values of investigated Zn–Fe alloy the defined phase was identified as a solid solution phase type ε. It also was shown that anodic linear voltammetry accomplished in alkaline solutions is more sensitive to the identification of the phase composition of zinc alloys than the traditional X-ray method and stripping voltammetry.

  8. Effect of alkaline solutions on the tensile properties of glass-polyester pipes

    Directory of Open Access Journals (Sweden)

    Putić Slaviša S.

    2011-01-01

    Full Text Available Construction materials, traditionally used in process equipment, are today successfully replaced by composite materials. Hence, many pipes are made of these materials. The subject of this study was the influence of liquids on the state of stresses and tensile strengths in the longitudinal and circumferential direction of glass-polyester pipes of a definite structure and known fabrication process. These analyses are of great importance for the use of glass-polyester pipes in the chemical industry. The tensile properties (the ultimate tensile strength and the modulus of elasticity were tested and determined for specimens cut out of the pipes; flat specimens for the tensile properties in the longitudinal direction and ring specimens for the tensile properties in the circumferential direction. First, the tension test was performed on virgin samples (without the influence of any liquid, to obtain knowledge about the original tensile properties of the material composite studied. Subsequently, the specimens were soaked in alkaline solutions: sodium hydroxide (strong alkali and ammonium hydroxide (weak alkali. These solutions were selected because of their considerable difference in pH values. The specimens and rings were left for 3, 10, 30 and 60 days in each liquid at room temperature. Then, the samples were tested on tension by the standard testing procedure. A comparison of the obtained results was made based on the pH values of the aggressive media in which the examined material had been soaked, as well as based on the original tensile properties and the number of days of treatment. Micromechanical analyses of sample breakage helped in the elucidation of the influence of the liquids on the structure of the composite pipe and enabled models and mechanisms that produced the change of strength to be proposed.

  9. The cost of alkaline solutions in ambulatory hemodialysis: an analysis about wasteful from the processes control.

    Science.gov (United States)

    de Moraes Junior, Celso Souza; de Mendonça, Ricardo Rodrigues Silveira; Hatem, Raquel Oliveira Rocha de Freitas; Souza, André Luiz Sampaio; Chaves, Adriana Rodrigues; Bastos, Marcus Gomes; Colugnati, Fernando Antônio Basile

    2014-01-01

    There are few studies about costs of inputs used in hemodialysis and among these expenditures, the compounds that make up the dialysate are one of the values considered as representative of this therapy. However, there aren't costs studies that guiding solutions. The objective of this article is discuss whether there is wasteful of alkaline solutions in ambulatory hemodialysis and hence the possibility of reduction in cost from the standardization process simulation of establishment of dialysate flow in periods between shifts in hemodialysis outpatients. Starting from an observational analytic, a simulation was performed twenty case scenarios, which ten cases established by standardizing processes control on the dialysate flow in recession. The combination of data was performed using as a basis the prices of three suppliers of alkali liquid or powder. It was observed among the scenarios with standardized processes, ranging between 7.7% and 33.3% savings in the alkaline solution cost (powder or liquid), by reducing waste. It is possible to restrain the wasteful use of alkaline solutions, both powder and liquid. Consequently, its cost from the patterning on reducing the flow of dialysate during the intervals between shifts observed in the outpatient hemodialysis. However, these results are conditional upon the commitment of health professionals, mainly to supervision exercise and control of activities in quality function deployment.

  10. Effect of different alkaline solutions on crystalline structure of cellulose at different temperatures.

    Science.gov (United States)

    Keshk, Sherif M A S

    2015-01-22

    Effect of alkaline solutions such as 10% NaOH, NaOH/urea and NaOH/ethylene glycol solutions on crystalline structure of different cellulosic fibers (cotton linter and filter paper) was investigated at room temperature and -4°C. The highest dissolution of cotton linter and filter paper was observed in NaOH/ethylene glycol at both temperatures. X-ray patterns of treated cotton linter with different alkaline solutions at low temperature showed only two diffractions at 2θ=12.5° and 21.0°, which belonged to the crystalline structure of cellulose II. CP/MAS (13)C NMR spectra showed the doublet peaks at 89.2 ppm and 88.3 ppm representing C4 resonance for cellulose I at room temperature, Whereas, at low temperature the doublet peaks were observed at 89.2 ppm and 87.8 ppm representing C4 resonance for cellulose II. Degree of polymerization of cellulose plays an important role in cellulose dissolution in different alkaline solutions and temperatures, where, a low temperature gives high dissolutions percentage with change in crystalline structure from cellulose I to cellulose II forms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Approximation for a Coulomb-Volkov solution in strong fields

    Science.gov (United States)

    Reiss, H. R.; Krainov, V. P.

    1994-08-01

    A simple analytical approximation is found for the wave function of an electron simultaneously exposed to a strong, circularly polarized plane-wave field and an atomic Coulomb potential. The approximation is valid when α0>>1, where α0 is the classical radius of motion of a free electron in the plane-wave field. This constraint is sufficiently mild at low frequencies that it makes possible a major extension of the lower bound of laser intensities for which Volkov-solution-based approximations are useful.

  12. Sorption potential of alkaline treated straw and a soil for sulfonylurea herbicide removal from aqueous solutions: An environmental management strategy.

    Science.gov (United States)

    Cara, Irina-Gabriela; Rusu, Bogdan-George; Raus, Lucian; Jitareanu, Gerard

    2017-11-01

    The adsorption potential of alkaline treated straw (wheat and corn) in mixture with soil, has been investigated for the removal of sulfonylurea molecules from an aqueous solutions. The surface characteristics were investigated by scanning electron microscopy and Fourier Transform Infrared - FTIR, while the adsorbent capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry. Surface analysis of alkaline treated straw samples by scanning electron microscopy - SEM showed the increasing of the surface roughness improving their functional surface activity. An increase (337.22 mg g -1 ) of adsorption capacity of sulfonylurea molecules was obtained for all studied straw. The Langmuir isotherm model was the best model for the mathematical description of the adsorption process indicating the forming of a surface sorption monolayer with a finite number of identical sites. The kinetics of sulfonylurea herbicide followed the pseudo-second order mechanism corresponding to strong chemical interactions. The results sustained that the alkaline treated straw have biosorption characteristics, being suitable adsorbent materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Characterization of Laboratory Prepared Concrete Pastes Exposed to High Alkaline and High Sodium Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-06-30

    The objective of this study was to identify potential chemical degradation mechanisms for the Saltstone Disposal Unit (SDU) concretes, which over the performance life of the structures may be exposed to highly alkaline sodium salt solutions containing sulfate, hydroxide, and other potentially corrosive chemicals in salt solution and saltstone flush water, drain water, leachate and / or pore solution. The samples analyzed in this study were cement pastes prepared in the SIMCO Technologies, Inc. concrete laboratory. They were based on the paste fractions of the concretes used to construct the Saltstone Disposal Units (SDUs). SDU 1 and 4 concrete pastes were represented by the PV1 test specimens. The paste in the SDU 2, 3, 5, and 6 concrete was represented by the PV2 test specimens. SIMCO Technologies, Inc. selected the chemicals and proportions in the aggressive solutions to approximate proportions in the saltstone pore solution [2, 3, 5, and 6]. These test specimens were cured for 56 days in curing chamber before being immersed in aggressive solutions. After exposure, the samples were frozen to prevent additional chemical transport and reaction. Selected archived (retrieved from the freezer) samples were sent to the Savannah River National Laboratory (SRNL) for additional characterization using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) spectroscopy. Characterization results are summarized in this report. In addition, a correlation between the oxide composition of the pastes and their chemical durability in the alkaline salt solutions is provided.

  14. DNA conformational equilibrium in the presence of Zn2+ ions in neutral and alkaline solutions

    Czech Academy of Sciences Publication Activity Database

    Sorokin, V. A.; Valeev, V. A.; Usenko, E. L.; Andrushchenko, Valery

    2012-01-01

    Roč. 50, č. 3 (2012), s. 854-860 ISSN 0141-8130 R&D Projects: GA ČR GAP208/10/0559 Institutional research plan: CEZ:AV0Z40550506 Keywords : DNA metallization * alkaline solution * DNA–metal complex * DNA helix–coil transition * differential UV spectroscopy * thermal denaturation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.596, year: 2012

  15. Removal of radioruthenium from alkaline intermediate level radioactive waste solution : a laboratory investigation

    International Nuclear Information System (INIS)

    Samanta, S.K.; Theyyunni, T.K.

    1994-01-01

    Various methods were investigated in the laboratory for the removal of radioruthenium from alkaline intermediate level radioactive waste solutions of reprocessing plant origin. The methods included batch equilibration with different ion exchangers and sorbents, column testing and chemical precipitation. A column method using zinc-activated carbon mixture and a chemical precipitation method using ferrous salt along with sodium sulphite were found to be promising for plant scale application. (author). 10 refs., 3 figs., 7 tabs

  16. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber

    OpenAIRE

    Cao, Ting-Ting; Wang, Yuan-Jing; Zhang, Yu-Qing

    2013-01-01

    Strongly alkaline electrolyzed water (SAEW) was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+) concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V) for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile prope...

  17. A study on the mechanism of stress corrosion cracking of duplex stainless steels in hot alkaline-sulfide solution

    Science.gov (United States)

    Chasse, Kevin Robert

    Duplex stainless steels (DSS) generally have superior strength and corrosion resistance as compared to most standard austenitic and ferritic stainless grades owing to a balanced microstructure of austenite and ferrite. As a result of having favorable properties, DSS have been selected for the construction of equipment in pulp and paper, chemical processing, nuclear, oil and gas as well as other industries. The use of DSS has been restricted in some cases because of stress corrosion cracking (SCC), which can initiate and grow in either the ferrite or austenite phase depending on the environment. Thorough understanding of SCC mechanisms of DSS in chloride- and hydrogen sulfide-containing solutions has been useful for material selection in many environments. However, understanding of SCC mechanisms of DSS in sulfide-containing caustic solutions is limited, which has restricted the capacity to optimize process and equipment design in pulp and paper environments. Process environments may contain different concentrations of hydroxide, sulfide, and chloride, altering corrosion and SCC susceptibility of each phase. Crack initiation and growth behavior will also change depending on the relative phase distribution and properties of austenite and ferrite. The role of microstructure and environment on the SCC of standard grade UNS S32205 and lean grade UNS S32101 in hot alkaline-sulfide solution were evaluated in this work using electrochemical, film characterization, mechanical testing, X-ray diffraction, and microscopy techniques. Microstructural aspects, which included residual stress state, phase distribution, phase ratio, and microhardness, were related to the propensity for SCC crack initiation in different simulated alkaline pulping liquors at 170 °C. Other grades of DSS and reference austenitic and superferritic grades of stainless steel were studied using exposure coupons for comparison to understand compositional effects and individual phase susceptibility

  18. Evaluating Growth of Zeolites on Fly Ash in Hydro-Thermally Heated Low Alkaline Solution

    Science.gov (United States)

    Jha, Bhagwanjee; Singh, D. N.

    2017-12-01

    Fly ash has been well established materials for synthesis of zeolites, under hydrothermally heated aqueous NaOH solution. Efficacy of such technique is reported to be improved when high molarity of NaOH is used. Consequently, highly alkaline waste solution, as by-product, is generally disposed of in the surrounding, which may contaminate the environment. In this context, less alkaline NaOH solution may become a safer option, which has not been tried in the past as per the literature. With this in view, the present study demonstrates effectiveness of the 0.5 M NaOH solution and critically monitors transition on the fly ash after hydrothermal treatment. As an enhancement over previous researchers, such activation of the fly ash finally results in remarkable morphological and mineralogical growth on the bulk material (the residue), which comprises of new nano-sized crystals (the zeolites Na-P1 and natrolite), after 24 h of activation of the fly ash.

  19. Severe corrosion of copper in a highly alkaline egg white solution due to a biuret corrosion reaction

    International Nuclear Information System (INIS)

    Liu, Xun; Hu, Wenyuan; Yang, Shan; Li, Zhaoqian; Pei, Chonghua; Zhou, Yong; Yin, Guanfu

    2015-01-01

    Highlights: • Egg whites can accelerate the corrosion of copper. • The corrosion rate of copper is closely related to the pH values. • The mechanism of the strong corrosion is due to a biuret corrosion reaction. - Abstract: Through investigating the interaction between copper metal and egg whites as well as the effects of pH, oxygen and the species of alkalis on copper corrosion rate, an unusual severe corrosion of copper metal in a highly alkaline egg white solution was found. The mechanism was investigated through detailed characterizations using a scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and UV–visible absorption spectroscopy. The severe corrosion was mainly due to the formation of a hydroxyl–peptide–copper multicomponent stable soluble complex, which the biuret reaction also produces

  20. Pitting corrosion of friction stir welded aluminum alloy thick plate in alkaline chloride solution

    International Nuclear Information System (INIS)

    Xu Weifeng; Liu Jinhe; Zhu Hongqiang

    2010-01-01

    The pitting corrosion of different positions (Top, Middle and Bottom) of weld nugget zone (WNZ) along thickness plate in friction stir welded 2219-O aluminum alloy in alkaline chloride solution was investigated by using open circuit potential, cyclic polarization, scanning electron microscopy and atomic force microscope. The results indicate that the material presents significant passivation, the top has highest corrosion potential, pitting potential and re-passivation potential compared with the bottom and base material. With the increase of traverse speed from 60 to 100 mm/min or rotary speed from 500 to 600 rpm, the corrosion resistance decreases.

  1. Effect of Additional Sulfide and Thiosulfate on Corrosion of Q235 Carbon Steel in Alkaline Solutions

    Directory of Open Access Journals (Sweden)

    Bian Li Quan

    2016-01-01

    Full Text Available This paper investigated the effect of additional sulfide and thiosulfate on Q235 carbon steel corrosion in alkaline solutions. Weight loss method, scanning electron microscopy (SEM equipped with EDS, X-ray photoelectron spectroscopy (XPS, and electrochemical measurements were used in this study to show the corrosion behavior and electrochemistry of Q235 carbon steel. Results indicate that the synergistic corrosion rate of Q235 carbon steel in alkaline solution containing sulfide and thiosulfate is larger than that of sulfide and thiosulfate alone, which could be due to redox reaction of sulfide and thiosulfate. The surface cracks and pitting characteristics of the specimens after corrosion were carefully examined and the corrosion products film is flake grains and defective. The main corrosion products of specimen induced by S2− and S2O32- are FeS, FeS2, Fe3O4, and FeOOH. The present study shows that the corrosion mechanism of S2− and S2O32- is different for the corrosion of Q235 carbon steel.

  2. Experimental and theoretical investigation on corrosion inhibition of AA5052 aluminium alloy by L-cysteine in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dapeng; Gao, Lixin [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Zhang, Daquan, E-mail: zhangdaquan@shiep.edu.cn [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Yang, Dong [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Wang, Hongxia; Lin, Tong [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia)

    2016-02-01

    The corrosion inhibition of L-cysteine on AA5052 aluminium alloy in 4 mol/L NaOH solution was investigated by hydrogen gas evolution experiment, polarisation curve, galvanostatic discharge, electrochemical impedance spectroscopy measurements and quantum chemical calculations. The adsorption of L-cysteine on aluminium alloy surface obeyed the amended Langmuir's adsorption isotherm. The polarisation curves indicated that L-cysteine acted as a cathodic inhibitor to inhibit cathodic reaction. The inhibition mechanism was dominated by the geometric covering effect. The galvanostatic discharge shows that the additives restrain the hydrogen evolution and increase the anodic utilization rate. Quantum chemical calculations indicated that L-cysteine molecules mainly interacted with on the carboxyl groups on the aluminium alloy surface. A strong hybridization occurred between the s-orbital and p-orbital of reactive sites in the L-cysteine molecule and the sp-orbital of Aluminium. - Highlights: • L-cysteine was used as corrosion inhibitor for Al alloy in alkaline solution. • Adsorption of L-cysteine on Al alloy surface obeyed the amended Langmuir's isotherm. • L-cysteine molecules interacted with the carboxyl groups on the Al alloy surface. • A strong orbital hybridization occurred between the reactive sites in L-cysteine and Al.

  3. Efficient removal of lead from solution by celery-derived biochars rich in alkaline minerals.

    Science.gov (United States)

    Zhang, Tao; Zhu, Xiaoxiao; Shi, Lingna; Li, Jianfa; Li, Saijun; Lü, Jinhong; Li, Yimin

    2017-07-01

    Biochars were produced from celery biomass by slow pyrolysis at 350 and 500°C, and featured by high content of alkaline minerals namely salts of alkali and alkaline earth metals. The biochars' efficiency on removing Pb 2+ from solution was investigated, and two biochars derived from celery stalk (StC350 and StC500) showed higher Pb 2+ sorption capacity (288 and 304mg/g) than most biochars reported previously. The sorption mechanisms involving precipitation, cation exchange and surface complexation are related to three biochar fractions namely water-soluble matter, acid-soluble substances and insoluble organic carbon. The relative contributions of water-soluble matter and acid-soluble substances to the total Pb 2+ removal were 59.8% and 36.6% for the StC350 biochar, and 62.8% and 34.9% for the StC500 biochar, respectively. The results indicate that biochars derived from vegetable wastes are potential candidates for efficient sorption of heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Strong solutions of semilinear stochastic partial differential equations

    Czech Academy of Sciences Publication Activity Database

    Hofmanová, Martina

    2013-01-01

    Roč. 20, č. 3 (2013), s. 757-778 ISSN 1021-9722 R&D Projects: GA ČR GAP201/10/0752 Institutional support: RVO:67985556 Keywords : stochastic partial differential equations * strongly elliptic differential operator * strongly continuous semigroup Subject RIV: BA - General Mathematics Impact factor: 0.971, year: 2013 http://library.utia.cas.cz/separaty/2013/SI/hofmanova-0393085.pdf

  5. Properties of altered soils by alkaline solution: contribution in the performance evaluation of repositories

    International Nuclear Information System (INIS)

    Calabria, Jaqueline Alves de Almeida

    2015-01-01

    evaluated samples (less than 20% after 10 days of equilibrium), being the best performance one, the nitosoil sample whose K d values varied from 11.78 to 63.05 mL.g -1 . In a subsequent step, the clay soil, was submitted to the alkaline solution interaction, in order to investigate possible alterations on the sorption properties and hydraulic conductivity of this soil. Using the sorption parameters, obtained from data fitted isotherms, the retardation factor, R, was estimated for the samples before and after the interaction. It was demonstrated that the alkaline alteration promotes damages to sorption properties of Cs, once the R became significantly smaller (about 1000 times) after the interaction. The hydraulic conductivity in turn increased slightly (3,91x10 -8 cm.s -1 to 5,08 x 10 -8 cm.s -1 ). It was concluded that these changes were due, mainly, to the dissolution of minerals present in the clay soil (kaolinite and quartz), associated with the incorporation of K and Ca from the alkaline solution, resulting, probably, in the formation of hydrated calcium silicate phases. Additionally, the effects of alkaline solution on the properties of a commercial bentonite were studied. Contrary to the clay soil, it was observed a gain in the sorption characteristics, with K d (Cs) increasing from 760.05 mL.g -1 to 1311.80 mL.g -1 and Q max from 36.32 mg.g -1 to 52.13 mg.g -1 , with the corresponding increase in the retardation coefficient, R. The dissolution of the clay minerals from the initial sample and the incorporation of Mg, K e Ca coming from the alkaline solution, generating smectite of different kinds, were considered as the main mineralogical changes responsible for the modifications in sorption parameters. The different behavior between the two evaluated samples, soil and bentonite, confirms that the nature and extension of changes observed, when mineral samples interact with alkaline solution, depend on the chemical/mineralogical composition of the solid material

  6. Effect of alkaline earth metal and magnesium cations on cadmium extraction from chloride solutions by tributyl phosphate

    International Nuclear Information System (INIS)

    Prokuev, V.A.; Belousov, E.A.

    1985-01-01

    At 298 K thermodynamic constants of cadmium (2) extraction from chloride solutions of magnesium, calcium, strontium and barium by tributyl phosphate are calculated. It is established, that logarithm of the thermodynamic extraction constant is in a linear dependence from the change in the cation hydration enthalpy in agqueous solution. It is shown, that activity coefficient of neutral complex CdVCl 2 differs from one, and it is the higher the more stable the complex is in alkaline earth metal chloride solutions

  7. Moderately strong pump-induced ultrafast dynamics in solution

    Energy Technology Data Exchange (ETDEWEB)

    Shen, H.F. [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); School of Physical Science and Technology, ShanghaiTech University (China); University of Chinese Academy of Sciences (China); Zhang, Yizhu, E-mail: zhangyz@sari.ac.cn [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); Yan, T.-M., E-mail: yantm@sari.ac.cn [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); Wang, Z.Y. [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); School of Physical Science and Technology, ShanghaiTech University (China); Jiang, Y.H., E-mail: jiangyh@sari.ac.cn [Shanghai Advanced Research Institute, Chinese Academy of Sciences (China); School of Physical Science and Technology, ShanghaiTech University (China)

    2016-09-12

    Graphical abstract: Moderately strong pump pulse is applied to the transient absorption spectrum. The pump and dump processes (resonant impulsive stimulated Raman scattering) finished in one single pump pulse in moderately strong regime make the observation of high-lying excited state dynamics possible. - Highlights: • The pulse intensity in transient absorption spectrum are experimentally studied. • The higher nonlinear susceptibility responses are observed. • The resonant impulsive stimulated Raman scattering. • New dynamics information in strong pump field. - Abstract: The transient transmittance spectra of laser dye IR144 in methanol were investigated experimentally in the moderately strong pump-probe field. Observed emission spectra in the red edge of the incident-field bandwidth, created by resonant impulsive stimulated Raman scattering (RISRS), display significant nonlinear intensity dependence as the pulse intensity increases. Dynamic perspectives of RISRS spectra can be understood well in a wavepacket picture. The excitation of high vibrational levels in the ground electronic state leading to the redshift of emissions presents high dependence of the pump-pulse intensity and ultrafast dynamical features, mapping the spatial overlap and separation of ground and excited wave functions and resolving the ultrafast vibrational relaxation in the femtosecond regime.

  8. The cathodic reduction of dioxygen on uranium oxide in dilute alkaline aqueous solution

    International Nuclear Information System (INIS)

    Hocking, W.H.; Betteridge, J.S.; Shoesmith, D.W.

    1991-09-01

    The cathodic reduction of dioxygen on uranium oxide in dilute alkaline aqueous solutions has been investigated within the context of a program to develop a comprehensive model to predict the behaviour of used CANDU (Canada Deuterium Uranium) nuclear fuel under disposal-vault conditions. Two different kinds of ceramic UO 2 were studied: reactor-grade CANDU fuel with normal p-type electrical conductivity and low-resistance material that exhibits n-type photoelectrochemical behaviour. The transport of electroactive species in solution was controlled by varying the rotation rate of rotating disc electrodes (RDE) and rotating ring-disc electrodes (RRDE). Steady-state polarization measurements were made using the current-interrupt method to compensate for the potential drop caused by ohmic resistance. Any release of peroxide to solution from the UO 2 (disc) surface could be monitored by oxidizing it at the Au ring of an RRDE. The existing theory for the cathodic 0 2 -reduction process as applied to RDE and RRDE experiments has been reviewed as a starting point for the interpretation of the results obtained in our work. (37 figs., 2 tabs., 170 refs.)

  9. Strong Feller solutions to SPDEďs are strong Feller in the weak topology

    Czech Academy of Sciences Publication Activity Database

    Maslowski, Bohdan; Seidler, Jan

    2001-01-01

    Roč. 148, č. 2 (2001), s. 111-129 ISSN 0039-3223 R&D Projects: GA ČR GA201/98/1454 Keywords : strong Feller property% stochastic parabolic equations Subject RIV: BA - General Mathematics Impact factor: 0.399, year: 2001

  10. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Cao

    Full Text Available Strongly alkaline electrolyzed water (SAEW was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+ concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  11. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Science.gov (United States)

    Cao, Ting-Ting; Wang, Yuan-Jing; Zhang, Yu-Qing

    2013-01-01

    Strongly alkaline electrolyzed water (SAEW) was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+) concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V) for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  12. On the Strong Solution for the 3D Stochastic Leray-Alpha Model

    Directory of Open Access Journals (Sweden)

    Gabriel Deugoue

    2010-01-01

    Full Text Available We prove the existence and uniqueness of strong solution to the stochastic Leray-α equations under appropriate conditions on the data. This is achieved by means of the Galerkin approximation scheme. We also study the asymptotic behaviour of the strong solution as alpha goes to zero. We show that a sequence of strong solutions converges in appropriate topologies to weak solutions of the 3D stochastic Navier-Stokes equations.

  13. On the Strong Solution for the 3D Stochastic Leray-Alpha Model

    Directory of Open Access Journals (Sweden)

    Deugoue Gabriel

    2010-01-01

    Full Text Available Abstract We prove the existence and uniqueness of strong solution to the stochastic Leray- equations under appropriate conditions on the data. This is achieved by means of the Galerkin approximation scheme. We also study the asymptotic behaviour of the strong solution as alpha goes to zero. We show that a sequence of strong solutions converges in appropriate topologies to weak solutions of the 3D stochastic Navier-Stokes equations.

  14. Guanidinium Group Remains Protonated in a Strongly Basic Arginine Solution.

    Science.gov (United States)

    Xu, Bo; Jacobs, Michael I; Kostko, Oleg; Ahmed, Musahid

    2017-06-20

    Knowledge of the acid dissociation constant of an amino acid has very important ramifications in the biochemistry of proteins and lipid bilayers in aqueous environments because charge and proton transfer depend on its value. The acid dissociation constant for the guanidinium group in arginine has historically been posited as 12.5, but there is substantial variation in published values over the years. Recent experiments suggest that the dissociation constant for arginine is much higher than 12.5, which explains why the arginine guanidinium group retains its positive charge under all physiological conditions. In this work, we use X-ray photoelectron spectroscopy to study unsupported, aqueous arginine nanoparticles. By varying the pH of the constituent solution, we provide evidence that the guanidinium group is protonated even in a very basic solution. By analyzing the energy shifts in the C and N X-ray photoelectron spectra, we establish a molecular level picture of how charge and proton transport in aqueous solutions of arginine occur. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A Strongly Calc-alkaline Suite in the Midst of the Tholeiitic Columbia River Basalt Province: Implications for Generating the Calc-alkaline Trend Without Subduction Processes

    Science.gov (United States)

    Steiner, A. R.; Streck, M. J.

    2012-12-01

    The mid-Miocene lavas of the Strawberry Volcanics (SV), distributed over 3,400 km2 in NE Oregon, comprise a diverse volcanic suite, which span the range of compositions from basalt to rhyolite. The volcanic suite is mainly composed of calc-alkaline (CA) basaltic andesite and andesite, yet tholeiitic (TH) lavas of basalt to andesite occur as well. The SV lies in the heart of nearly coeval flood basalts of the Columbia River province of the Pacific Northwest. The unique combination of strongly CA rocks of the SV in a non-subduction setting provide an excellent opportunity to study controls on inducing CA evolution in the midst of a TH province and independent of processes taking places at an active subduction zone. New 40Ar/39Ar ages indicate CA basaltic andesites to andesites of the SV erupted at least from 14.78±0.13 Ma to 12.44±0.12 Ma demonstrating that CA magmatism of the SV was ongoing during the eruptions of the tholeiitic Wanapum Basalt member of the Columbia River Basalt Group (CRBG). This range will likely be extended to even older ages in the future because existent age dates did not include samples from near the base of the SV. Thickness of intermediate lavas flows of the SV range from 15 m to as thin as 2 m and lavas are characterized by mostly phenocryst poor lithologies. When phenocrysts are abundant they are very small suggesting growth late during eruption. Single lava flow sections can include on the order of 30 conformable flows, testifying to a vigorous eruption history. The thickest andesitic sections are located in the glacially carved mountains of the Strawberry Mountain Wilderness (i.e. Strawberry Mountain, High Lake, and Slide Lake) where several vent complexes are exposed, which are delineated by dikes and plugs with finely interlocking plutonic textures, cross-cutting SV lava flows. Dikes generally strike NW-SE. Subtle variations in major and trace element compositions exist between TH and CA lavas of the SV. The CA lavas of the SV are

  16. Far from equilibrium enstatite dissolution rates in alkaline solutions at earth surface conditions

    Science.gov (United States)

    Halder, Sougata; Walther, John V.

    2011-12-01

    Far from equilibrium enstatite dissolution rates both open to atmospheric CO 2 and CO 2 purged were measured as a function of solution pH from 8 to 13 in batch reactors at room temperature. Congruent dissolution was observed after an initial period of incongruent dissolution with preferential Si release from the enstatite. Steady-state dissolution rates in open to atmospheric CO 2 conditions decrease with increase in solution pH from 8 to 12 similar to the behavior reported by other investigators. Judging from the pH 13 dissolution rate, rates increase with pH above pH 12. This is thought to occur because of the increase in overall negative surface charges on enstatite as Mg surface sites become negative above pH 12.4, the pH of zero surface charge of MgO. Steady-state dissolution rates of enstatite increase above pH 10 when CO 2 was purged by performing the experiments in a N 2 atmosphere. This suggests inhibition of dissolution rates above pH 10 when experiments were open to the atmosphere. The dissolved carbonate in these solutions becomes dominantly CO 32- above pH 10.33. It is argued that CO 32- forms a >Mg 2-CO 3 complex at positively charged Mg surface sites on enstatite, resulting in stabilization of the surface Si-O bonds. Therefore, removal of solution carbonate results in an increase in dissolution rates of enstatite above pH 10. The log rate of CO 2-purged enstatite dissolution in moles per cm 2 per s as a function of increasing pH above pH 10 is equal to 0.35. This is consistent with the model of silicate mineral dissolution in the absence of surface carbonation in alkaline solutions proposed earlier in the literature.

  17. Investigation of electrochemical synthesis of ferrate, Part I: Electrochemical behavior of iron and its several alloys in concentrated alkaline solutions

    Directory of Open Access Journals (Sweden)

    Čekerevac Milan I.

    2009-01-01

    cyclic voltammetry, galvanostatic and potentiostatic pulse method. Cyclic voltammetry gave useful data on potential regions where ferrate(VI formation is to be expected in the course of transpassive anodic oxidation of iron and some of its alloys, and its stability in the electrolytes of different composition. In addition, step-wise oxidation of iron in anodic oxidation is confirmed. Galvanostatic pulse experiments confirmed the character of successive anodic oxidation of iron, as the three-step process of ferrate(VI formation is clearly observed. In the cathodic pulse complex reduction of ferrate (VI, firstly to Fe(III species and then to mixed Fe(II and Fe(III compounds and finally to elementary iron is confirmed. The significant difference between the mechanisms of anodic oxidation of pure iron and low carbon steel at the one side and electrical ferrous-silicon steel at the other is observed. The influence of material chemical composition on the electrochemical behavior of electrode in course of anodic polarization in strong alkaline solutions is discussed in terms of composition of passivating layer formed on the electrode. On the base of the experimental data, efficient synthesis of ferrate(VI can be expected in the region of anodic potentials between + 0,55 and + 0,75 V against Hg|HgO reference electrode in the same solution, depending on the anode materials composition, in the alkaline electrolytes concentration between 10 and 15 M.

  18. Oxygen reduction at platinum nanoparticles supported on carbon cryogel in alkaline solution

    Directory of Open Access Journals (Sweden)

    N. R. ELEZOVIC

    2007-07-01

    Full Text Available The oxygen reduction reaction was investigated in 0.1 M NaOH solution, on a porous coated electrode formed of Pt particles supported on carbon cryogel. The Pt/C catalyst was characterized by the X-ray diffraction (XRD, transmission electron microscopy (TEM and cyclic voltammetry techniques. The results demonstrated a successful reduction of Pt to metallic form and homogenous Pt particle size distribution with a mean particle size of about 2.7 nm. The ORR kinetics was investigated by linear sweep polarization at a rotating disc electrode. The results showed the existence of two E – log j regions, usually referred to polycrystalline Pt in acid and alkaline solution. At low current densities (lcd, the Tafel slope was found to be close to –2.3RT/F, while at high current densities (hcd it was found to be close to –2×2.3RT/F. It is proposed that the main path in the ORR mechanism on Pt particles was the direct four-electron process, with the transfer of the first electron as the rate determining step. If the activities are expressed through the specific current densities, a small enhancement of the catalytic activity for Pt/C was observed compared to that of polycrystalline Pt. The effect of the Pt particle size on the electrocatalysis of oxygen reduction was ascribed to the predominant (111 facets of the platinum crystallites.

  19. Oxidation of arsenite by molecular oxygen in strong alkaline solution under γ-radiation

    International Nuclear Information System (INIS)

    Burkitbaev, M.M.

    1996-01-01

    The kinetics and mechanism of radiation-stimulated process in 1 mole/1 l of potassium hydroxide have been studied. Radiation chemical yield of (G(As)(Y)) oxygenation grows directly proportionally to oxygen concentration and inversely proportionally to dose rate in proportion 1/2. Mechanism of oxidation, including two chain cycles (long chain cycle - with participation of O - ; O 2 - ; O 3 - radicals and short chain one -with participation of arsenic contenting radicals: As(IV), As(IV)O, As(IV)O 2 ) is proposed. (author)

  20. Divalent metal ion effect on helix-coil transition of high molecular weight DNA in neutral and alkaline solutions

    Czech Academy of Sciences Publication Activity Database

    Sorokin, V. A.; Valeev, V. A.; Usenko, E. L.; Andrushchenko, Valery

    2011-01-01

    Roč. 48, č. 2 (2011), s. 369-374 ISSN 0141-8130 R&D Projects: GA ČR GAP208/10/0559 Institutional research plan: CEZ:AV0Z40550506 Keywords : DNA melting * alkaline solution * metal complex * differential UV spectroscopy * thermal denaturation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.453, year: 2011

  1. Specific features of Zn2+, Co2+ and Ni2+ ion binding to DNA in alkaline solutions

    Czech Academy of Sciences Publication Activity Database

    Sorokin, V. A.; Valeev, V. A.; Usenko, E. L.; Rakovsky, Y. P.; Andrushchenko, Valery

    2013-01-01

    Roč. 55, Apr (2013), s. 137-141 ISSN 0141-8130 R&D Projects: GA ČR GAP208/10/0559 Institutional support: RVO:61388963 Keywords : DNA metal lization * m-form * alkaline solution * ethidium bromide * DNA- metal complex Subject RIV: CE - Biochemistry Impact factor: 3.096, year: 2013

  2. Establishing the potential dependent equilibrium oxide coverage on platinum in alkaline solution and its influence on the oxygen reduction

    DEFF Research Database (Denmark)

    Wiberg, Gustav; Arenz, Matthias

    2012-01-01

    Publication year: 2012 Source:Journal of Power Sources, Volume 217 Gustav K.H. Wiberg, Matthias Arenz The oxidation process of polycrystalline platinum subjected to alkaline solution is re-examined using a combination of cyclic voltammetry and potential hold techniques in Ar, H2 and O2 purged 0.1...

  3. Uranium mobility during interaction of rhyolitic glass with alkaline solutions: dissolution of glass

    Science.gov (United States)

    Zielinski, Robert A.

    1977-01-01

    This report concerns investigations designed to identify the important physical and chemical parameters influencing the rate of release of uranium from glass shards of rhyolitic air-fall ash. Oxidizing, silica undersaturated, alkaline solutions are eluted through a column of rhyolitic glass shards at a carefully controlled temperature, pressure, and flow rate. The solutions are monitored for the concentration of uranium and selected additional elements (Si, K, Li, F), and the glass is recovered and examined for physical and/or chemical evidence of attack. The flushing mode is designed to mimic leaching of glass shards by intermittent, near-surface waters with which the glass is not in equilibrium. Reported rates are applicable only to the experimental conditions (120?C, 7,000 psi), but it is assumed that the reaction mechanisms and the relative importance of rate-influencing parameters remain unchanged, at reduced temperature and pressure. Results of the above experiment indicate that silica and uranium are released from glass shards at comparable rates, while lithium and potassium are released faster and fluorine slower than either Si or U. Rates of release of silica and uranium correlate positively with the surface area of the shards. Rhyolitic shards release uranium at faster rates than rhyodacitic shards of comparable surface area. Changes in the shards resulting from experimental treatment and observed in the original glass separates from an Oligocene ash (compared to a Pleistocene ash) include; surface pitting, increased surface area, devitrification rinds (effect of temperature, pressure, solution composition, and flow rate on the relative mobility of U, Si, Li, F, and K.

  4. Evaluation of alkaline electrolyzed water to replace traditional phosphate enhancement solutions: Effects on water holding capacity, tenderness, and sensory characteristics.

    Science.gov (United States)

    Rigdon, Macc; Hung, Yen-Con; Stelzleni, Alexander M

    2017-01-01

    Sixty-four pork loins were randomly assigned to one of four treatments to evaluate the use of alkaline electrolyzed reduced water as a replacement for traditional enhancement solutions. Treatments included: alkaline electrolyzed reduced water (EOH; pH≈11.5), EOH plus 2.5% potassium-lactate (EOK), industry standard (IS; 0.35% sodium tri-polyphosphate, 0.14% sodium chloride, 2.5% potassium-lactate), and no enhancement (CON). After enhancement (targeting 110%) and rest period, chops were cut (2.54-cm) to test treatment effects on water holding capacity, Warner-Bratzler shear force (WBSF), and sensory attributes. Despite its alkaline nature EOH chops exuded more water (P0.05) to EOK, however CON and EOK both lost more moisture (Palkaline electrolyzed reduced water did not improve WBSF or sensory characteristics compared to IS treated chops. As a stand-alone enhancement solution alkaline electrolyzed reduced water was not a suitable replacement for industry standard solutions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Impact of an Alkaline Solution on the Chemistry, Mineralogy, and Sorption Properties of a Typic Rhodudult Soil

    Directory of Open Access Journals (Sweden)

    Jaqueline Alves de Almeida Calábria

    2017-11-01

    Full Text Available Abstract The preferred option for disposal of short-lived low and intermediate level radioactive wastes is a near surface disposal facility in which soil is one of the barriers that avoid radionuclide migration outside the controlled area. For construction of that kind of facility, concrete is widely used, and its interaction with water induces its degradation, resulting in a high pH solution. The alkaline solution may affect the near-field environment of radioactive waste repositories, including the soil, promoting mineralogical alterations that result in significant changes in key properties of materials, compromising their performance as safety components. In this study, a sample of a Brazilian Typic Rhodudult soil, previously investigated concerning its performance for Cs sorption, was subjected to interaction with the alkaline solution for 24 h and for 7, 14, and 28 days in order to evaluate the impact on its chemical, mineralogical, and sorption properties. X-ray diffraction (XRD, energy dispersive X-ray spectroscopy (EDX, atomic absorption spectrometry (AAS, scanning electron microscopy (SEM, and electron microprobe analysis were performed before and after each alteration period. Results indicated dissolution of minerals, such as kaolinite and quartz, associated with incorporation of K and Ca from the alkaline solution, likely resulting in the formation of hydrated calcium silicate phases (CSH, which are expected to be worse sorbents for alkaline elements (e.g., Cs than the original minerals. The Kd values for Cs in the altered samples also decreased according to the alteration period, demonstrating that alkaline interaction effectively modifies the soil sorption properties for Cs.

  6. Production of ultrafine zinc powder from wastes containing zinc by electrowinning in alkaline solution

    Directory of Open Access Journals (Sweden)

    Zhao Youcai

    2013-12-01

    Full Text Available Production of ultrafine zinc powder from industrial wastes by electrowinning in alkaline solution was studied. Stainless steel and magnesium electrodes were used as anode and cathode, respectively. Morphology, size distribution and composition of the Zn particles were characterized by Scanning Electron Microscopy, Laser Particle Size Analyzer, and Inductive Coupled Plasma Emission Spectrometer. The required composition of the electrolyte for ultrafine particles was found to be 25-35 g/L Zn, 200-220 g/L NaOH and 20-40 mg/L Pb. The optimal conditions were a current density of 1000-1200 A/m² and an electrolyte temperature of 30-40 °C. The results indicated that the lead additive exerted a beneficial effect on the refining of the particles, by increasing the cathodic polarization. Through this study, ultrafine zinc powder with a size distribution of around 10 μm could be produced, and considerably high current efficiencies (97-99 % were obtained.

  7. Structural and thermal characterization of hemicelluloses isolated by organic solvents and alkaline solutions from Tamarix austromongolica.

    Science.gov (United States)

    Sun, Yong-Chang; Wen, Jia-Long; Xu, Feng; Sun, Run-Cang

    2011-05-01

    Three organosolv and three alkaline hemicellulosic fractions were prepared from lignocellulosic biomass of the fast-growing shrub Tamarix austromongolica (Tamarix Linn.). Sugar analysis revealed that the organosolv-soluble fractions contained a higher content of glucose (33.7-6.5%) and arabinose (14.8-5.6%), and a lower content of xylose (62.2-54.8%) than the hemicellulosic fractions isolated with aqueous alkali solutions. A relatively high concentration of alkali resulted in a decreasing trend of the xylose/4-O-methyl-D-glucuronic acid ratio in the alkali-soluble fractions. The results of NMR analysis supported a major substituted structure based on a linear polymer of β-(1→4)-linked d-xylopyranosyl residues, having ramifications of α-L-arabinofuranose and 4-O-methyl-D-glucuronic acid residues monosubstituted at O-3 and O-2, respectively. Thermogravimetric analysis revealed that one step of major mass loss occurred between 200-400°C, as hemicelluloses devolatilized with total volatile yield of about 55%. It was found that organosolv-soluble fractions are more highly ramified, and showed a higher thermal stability than the alkali-soluble fractions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. A membraneless microscale fuel cell using non-noble catalysts in alkaline solution

    Science.gov (United States)

    Sung, Woosuk; Choi, Jin-Woo

    This paper presents the development of a novel liquid-based microscale fuel cell using non-noble catalysts in an alkaline solution. The developed fuel cell is based on a membraneless structure. The operational complications of a proton exchange membrane lead the development of a fuel cell with the membraneless structure. Non-noble metals with relatively mild catalytic activity, nickel hydroxide and silver oxide, were employed as anode and cathode catalysts to minimize the effect of cross-reactions with the membraneless structure. Along with nickel hydroxide and silver oxide, methanol and hydrogen peroxide were used as a fuel at anode and an oxidant at cathode. With a fuel mixture flow rate of 200 μl min -1, a maximum output power density of 28.73 μW cm -2 was achieved. The developed fuel cell features no proton exchange membrane, inexpensive catalysts, and simple planar structure, which enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable applications.

  9. Effective Uranium (VI) Sorption from Alkaline Solutions Using Bi-Functionalized Silica-Coated Magnetic Nanoparticles

    International Nuclear Information System (INIS)

    Chen, X.; He, L.; Liu, B.; Tang, Y.

    2015-01-01

    High temperature gas reactor is one of generation IV reactors that can adapt the future energy market, of which the preparation of fuel elements will produce a large amount of radioactive wastewater with uranium and high-level ammonia. Sorption treatment is one of the most important method to recover uranium from wastewater. However, there are few report on uranium sorbent that can directly be applied in wastewater with ammonia. Therefore, the development of a sorbent that can recover uranium in basic environment will greatly decrease the cost of fuel element production and the risk of radioactive pollution. In this work, ammonium-phosphonate-bifunctionalized silica-coated magnetic nanoparticles has been developed for effective sorption of uranium from alkaline media, which are not only advantaged in the uranium separation from liquid phase, but also with satisfactory adsorption rate, amount and reusability. The as-prepared sorbent is found to show a maximum uranium sorption capacity of 70.7 mg/g and a fast equilibrium time of 2 h at pH 9.5 under room temperature. Compared with the mono-functionalized (phosphonate alone and ammonium alone) particles, the combination of the bi-functionalized groups gives rise to an excellent ability to remove uranium from basic environment. The sorbent can be used as a promising solid phase candidate for highly-efficient removal of uranium from basic solution. (author)

  10. Zinc electrodeposition from flowing alkaline zincate solutions: Role of hydrogen evolution reaction

    Science.gov (United States)

    Dundálek, Jan; Šnajdr, Ivo; Libánský, Ondřej; Vrána, Jiří; Pocedič, Jaromír; Mazúr, Petr; Kosek, Juraj

    2017-12-01

    The hydrogen evolution reaction is known as a parasitic reaction during the zinc electrodeposition from alkaline zincate solutions and is thus responsible for current efficiency losses during the electrolysis. Besides that, the rising hydrogen bubbles may cause an extra convection within a diffusion layer, which leads to an enhanced mass transport of zincate ions to an electrode surface. In this work, the mentioned phenomena were studied experimentally in a flow through electrolyzer and the obtained data were subsequently evaluated by mathematical models. The results prove the indisputable influence of the rising hydrogen bubbles on the additional mixing of the diffusion layer, which partially compensates the drop of the current efficiency of the zinc deposition at higher current flows. Moreover, the results show that the current density ratio (i.e., the ratio of an overall current density to a zinc limiting current density) is not suitable for the description of the zinc deposition, because the hydrogen evolution current density is always involved in the overall current density.

  11. The inhibition of the spongy electrocrystallization of zinc from doped flowing alkaline zincate solutions

    Science.gov (United States)

    Wen, Yue-hua; Cheng, Jie; Zhang, Li; Yan, Xu; Yang, Yu-sheng

    The effects of the presence of additives like lead and tungstate ions in flowing alkaline zincate solutions on suppressing spongy zinc electrogrowth are examined. The results show that the two additives with optimal concentrations in flowing electrolytes can suppress spongy zinc initiation and propagation. And, the two additives can bring about more uniform and compact deposits and, thereby, reduce spongy zinc growth. The influence of lead and tungstate ions on the zinc deposition/dissolution is evaluated by cyclic voltammetry. It also shows that the addition of the two additives is largely a blocking action, and the co-deposition of lead and zinc ions may occur. The performance of the zinc-air flow battery with zinc regeneration electrolysis is determined. It shows that by the addition of 0.6 M Na 2WO 4 or 10 -4 M to 10 -3 M lead, compact or mixed compact-spongy zinc deposits are created and the favorable charge/discharge performance of the battery is achieved with an energy efficiency of approximately 60%.

  12. Effect of Alkaline Solution with Varying Mix Proportion on Geopolymer Mortar

    Science.gov (United States)

    Karuppuchamy, K.; Ananthkumar, M.; Raghavapriya, S. M.

    2018-02-01

    Cement production is attributed by emission of carbon dioxide which causes severe environmental impacts. This has led to the invention of special construction materials which can replace cement. On the other hand, these construction materials (like Fly ash, Metakaolin) also need to be inexpensive and should possess all the characteristics of cementitious materials. In this project, the effect of geopolymerization on the properties of the end product were studied with varying distillation of NaOH solution (10M, 12M and 15M) for different mix proportion (1:1, 1:2 and 1:3). Curing was done for 1 day at a temperature of 60°C and 80°C respectively. The densities, compressive strength, alkalinity, co-efficient of absorption were determined. As a result, the experiments showed the effect of factors such as mix proportion, curing temperature and curing day on the physical and mechanical properties such as mix proportion of the geopolymer concrete. Results of NaOH concentration of 12M concentration cured for 24 hours at 80°C and 60°C showed better mechanical performance than the rest of the concentrations.

  13. Critical anomalies of alkaline fading of phenolphthalein in the critical solution of 2-butoxyethanol + water

    Science.gov (United States)

    Du, Zhongyu; Yin, Handi; Hao, Zhiguo; Zheng, Peizhu; Shen, Weiguo

    2013-12-01

    We have used three-wavelength UV-spectrophotometry to study the reaction of the alkaline fading of phenolphthalein in the critical solution of 2-butoxyethanol + water. It was found that when the temperature was far away from the critical point, the values of the natural logarithm of the rate constant k and the natural logarithm of the chemical equilibrium K determined in our experiments had good linear relationships with the reciprocal of temperature, which served as the backgrounds and were used for correcting k and K in the critical region. The critical slowing down of the reaction and the critical anomaly of the chemical equilibrium were detected near the critical point. The value of the critical exponent characterizing the slowing down effect of the reaction rate was obtained to be 0.156, which was close to the value 0.11 associated with the heat capacity divergence and agreed with the theoretical prediction. The experimental result also confirmed the theoretical prediction of 0.11 for the critical exponent characterizing the weak divergence of the singularity of the chemical equilibrium.

  14. Removal and Recovery of Chromium from Solutions Simulating Tannery Wastewater by Strong Acid Cation Exchanger

    Directory of Open Access Journals (Sweden)

    Gulten Cetin

    2013-01-01

    Full Text Available The process in this study was conducted on removal of chromium(III in a solution simulating a typical spent chrome tanning bath by the resin having matrix of styrene-divinylbenzene-based macroporous sulphonate, Amberjet 1200Na. The column experiments were carried out with the bed volumes of the resin as 751 mL and 1016 mL for different installation systems of the laboratory-scale pilot plant. The feeding solutions in the bed volumes of 200 and 190 were used for each installation system. The regeneration behaviour of the resin was determined by using reverse regeneration procedure with the solution of hydrogen peroxide in alkaline. The regeneration kinetics of the exhausted resin was examined with a range of the solutions having different concentration series of the alkaline hydrogen peroxide. The solutions of the basic chromium sulphate were recycled for each installation system following the regeneration cycles. The chromium ions in effluent were quantitatively eluted, and satisfactory removal of chromium(III and recovery of chromium(VI were achieved.

  15. The reactivity of the electron formed in the radiolysis of aerated alkaline aqueous solutions containing tetracycline hydrochloride, at 77 Ksup(+)

    International Nuclear Information System (INIS)

    Guedes, S.M.L.; Vasconcellos, M.B.A.

    1986-01-01

    The radiolysis of tetracycline hydrochloride dissolved in aerated alkaline aqueous solutions containing 0.1, 0.5 and 1M NaOH at 77 K, followed by ESR is reported. The rate constants for the reactions between the electron and physical or chemical traps which are present in these solutions are calculated. The reactivity of electrons that are formed in the radiolysis of water decreases in the following proportions: physical traps: chemical traps: molecules of water (4.8x10sup(14) : 6.5x10sup(8) : 1.0). The electrons react preferentially with the solute instead of the solvent. (author)

  16. Roughness comparison of heat cured type of acrylic resin in disinfectant solution immersion (Immersion in a solution of alkaline peroxide and 75% Celery extract (Apium graveolens L

    Directory of Open Access Journals (Sweden)

    Dewi Puspitasari

    2016-08-01

    Full Text Available Acrylic resin denture base has the properties absorbing that affecting physical and mechanical properties. One of the physical properties of acrylic resin is surface roughness. The aim of the study was to find out the roughness effect on heat cured acrylic that was immersed in alkaline peroxide and 75% celery (Apium graveoens L extract as a disinfectant solution. The study was a true experimental and posttest with control group designed with a rectangular shape size 65 x 10 x 3.3 mm based on the ISO standard 1567, six samples were used for alkaline peroxide, celery extract 75% and aquadest group for 5 and 15 days. A Surface Roughness Tester was used for the surface roughness changes observation. The statistical test used One-way ANOVA and post hoc Bonferroni. The results of this study showed the value of roughness on 5 days for alkaline peroxide (1.51 µm is greater than celery extract (0.36µm and aquadest (0.30 µm. The soaking for 15 days in alkaline peroxide (1.52 µm is greater than 75% celery extracts (0.38 µm and aquadest (0.34 µm. Alkaline peroxide caused higher roughness value of heat cured acrylic resin than 75% celery extract.

  17. Hydrogen Evolution Reaction in Alkaline Solution: From Theory, Single Crystal Models, to Practical Electrocatalysts.

    Science.gov (United States)

    Zheng, Yao; Jiao, Yan; Qiao, Shizhang; Vasileff, Anthony

    2017-12-01

    The hydrogen evolution reaction (HER) is a fundamental process in electrocatalysis and plays an important role in energy conversion for the development of hydrogen-based energy sources. However, the considerably slow rate of the HER in alkaline conditions has hindered advances in water splitting techniques for high-purity hydrogen production. Differing from well documented acidic HER, the mechanistic aspects of alkaline HER are yet to be settled. Herein, we present a critical appraisal of alkaline HER electrocatalysis, with a special emphasis on the connection between fundamental surface electrochemistry on single crystal models and the derived molecular design principle for real-world electrocatalysts. By presenting some typical examples across theoretical calculations, surface characterization, and electrochemical experiments, we try to address some key ongoing debates to deliver a better understanding of alkaline HER at the atomic level. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Release of fission products from oxidised zircaloy cladding in contact with an alkaline solution

    International Nuclear Information System (INIS)

    Poulard, K.

    2001-09-01

    Before nuclear spent fuel reprocessing, the cladding tubes are sectioned into pieces called hulls in order to release the UO 2 pellets. The hulls are collected as solid wastes and were embedded inside a concrete structure until 1995. In the perspective of geological storage, a great interest is given to iodine release during contact between hulls and basic water infiltrated inside the concrete structure. Experiments were performed on zircaloy or zirconium oxidised samples representative of oxidised hulls surfaces. Corrosion tests were performed in autoclave. The specimens were exposed to a basic solution at 250 deg C, 275 deg C and 300 deg C. The corrosion tests were conducted during 12 weeks with regular sampling every two weeks. The partial dissolution of the oxide coating was studied using the rare earth europium element as a surface marker of zirconia. Such a choice is based on experimental results ensuring that this marker will not diffuse in the 250-300 deg C temperature range. Europium was introduced by ion implantation (Rp = 42 nm). The evolutions of europium concentration profiles measured at each corrosion step show that a non homogeneous dissolution of zirconia occurs in this alkaline medium. The mean dissolution rate is equal to 1 nm/day at 300 deg C. In order to analyse the mechanism involved in iodine migration, iodine atoms were introduced in samples by ion implantation. The iodine profile evolution allows to identify two steps in iodine release. A rapid desorption which could not be related to zirconia dissolution and then a stabilisation as far as low the iodine concentration (0.3 at.%) were reached. We demonstrated that hydrogen (representative of hydroxyl) migration in zirconia is clearly enhanced by the presence of iodine in the sample and that the iodine release is correlated to that of hydroxyl ions. The correlation of the behaviour between iodine and hydroxyl ions could be explained by the creation of complexes. (author)

  19. Steady-state analysis of the nickel oxide in neutral and weakly alkaline solutions

    International Nuclear Information System (INIS)

    Albu, C.; Deconinck, D.; Hotoiu, L.; Deconinck, J.; Topa, V.

    2013-01-01

    Thin passive nickel oxides are investigated in neutral and weakly alkaline pH solutions under steady-state conditions. The chemical species considered in the oxide film are nickel interstitials and vacancies, as well as oxygen vacancies. The set of differential equations used in this study is solved using the finite element method (FEM) and is able to reproduce the experimental data present in the literature. Steady-state oxide thickness variation with the applied electrode potential presents a linear behavior with an average slope of 2 nm/V. The role of dominant species in these thin films is investigated in terms of current density produced by the reactions at the interfaces, the reactions involving production and consumption of Ni 2+ vacancies playing a major role in the steady-state properties of the oxide. We show that the mass transport of species in the oxide is influenced more by the migration component of the flux than the diffusion component. Our results also show that the flux of Ni 2+ vacancies is approximately two orders of magnitude higher than the flux of oxygen vacancies and Ni 2+ interstitials, making them the dominant defects in the oxide (thus the p-type electronic character is present). Also, the Ni 2+ vacancies were found to have density levels of 10 20 –10 21 cm −3 close to the metal–film interface. Variations of the steady-state thickness and logarithm of the current density with the electrolyte pH, show a linear increase and decrease respectively. Some of these results are compared with data from experiments and simulations done on the iron oxide, showing that Ni forms steady-state passive films that are thinner than the ones formed on Fe under the same environment conditions (pH, temperature, and applied potential)

  20. Extraction process of U from its ores using solutions of alkaline earth carbonates and bicarbonates in presence of carbon dioxide

    International Nuclear Information System (INIS)

    Floreancig, Antoine; Schuffenecker, Robert.

    1976-01-01

    A process is described for extracting uranium from its ores, either directly in the ore deposit or after such ore bodies have been taken from the ground, comprising an oxidation-leaching stage followed by a recovery stage. The characteristic of this process is that in the leaching process, carbonate and bicarbonate solutions of an alkaline-earth metal are used under a pressure of carbon dioxide between zero and 60 bars and at a temperature of zero to 100 0 C [fr

  1. Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A.A. [Westinghouse Hanford Co., Richland, WA (United States); Olson, R.A.; Tennis, P.D. [Northwestern Univ., Evanston, IL (United States). Center for Advanced Cement-Based Materials] [and others

    1995-04-01

    Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter, the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO{sub 3}, quartz, and monosulfate Impedance spectra conform with the chemical and mineralogical data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite.

  2. Removal of dissolved actinides from alkaline solutions by the method of appearing reagents

    Science.gov (United States)

    Krot, Nikolai N.; Charushnikova, Iraida A.

    1997-01-01

    A method of reducing the concentration of neptunium and plutonium from alkaline radwastes containing plutonium and neptunium values along with other transuranic values produced during the course of plutonium production. The OH.sup.- concentration of the alkaline radwaste is adjusted to between about 0.1M and about 4M. [UO.sub.2 (O.sub.2).sub.3 ].sup.4- ion is added to the radwastes in the presence of catalytic amounts of Cu.sup.+2, Co.sup.+2 or Fe.sup.+2 with heating to a temperature in excess of about 60.degree. C. or 85.degree. C., depending on the catalyst, to coprecipitate plutonium and neptunium from the radwaste. Thereafter, the coprecipitate is separated from the alkaline radwaste.

  3. Investigation on the co-precipitation of transuranium elements from alkaline solutions by the method of appearing reagents

    International Nuclear Information System (INIS)

    Krot, N.; Shilov, V.; Bessonov, A.; Budantseva, N.; Charushnikova, I.; Perminov, V.; Astafurova, L.

    1996-06-01

    Highly alkaline radioactive waste solutions originating from production of plutonium for military purposes are stored in underground tanks at the U.S. Department of Energy Hanford Site. The purification of alkaline solutions from neptunium and plutonium is important in the treatment and disposal of these wastes. This report describes scoping tests with sodium hydroxide solutions, where precipitation techniques were investigated to perform the separation. Hydroxides of iron (III), manganese (II), cobalt (II, III), and chromium (III); manganese (IV) oxide, and sodium uranate were investigated as carriers. The report describes the optimum conditions that were identified to precipitate these carriers homogeneously throughout the solution by reductive, hydrolytic, or catalytic decomposition of alkali-soluble precursor compounds by a technique called the Method of Appearing Reagents. The coprecipitation of pentavalent and hexavalent neptunium and plutonium was investigated for the candidate agents under optimum conditions and is described in this report along with the following results. Plutonium coprecipitated well with all tested materials except manganese (IV) oxide. Neptunium only coprecipitated well with uranate. The report presents a hypothesis to explain these behaviors. Further tests with more complex solution matrices must be performed

  4. Investigation on the co-precipitation of transuranium elements from alkaline solutions by the method of appearing reagents

    Energy Technology Data Exchange (ETDEWEB)

    Krot, N.; Shilov, V.; Bessonov, A.; Budantseva, N.; Charushnikova, I.; Perminov, V.; Astafurova, L. [Russian Academy of Science (Russian Federation). Inst. of Physical Chemistry

    1996-06-06

    Highly alkaline radioactive waste solutions originating from production of plutonium for military purposes are stored in underground tanks at the U.S. Department of Energy Hanford Site. The purification of alkaline solutions from neptunium and plutonium is important in the treatment and disposal of these wastes. This report describes scoping tests with sodium hydroxide solutions, where precipitation techniques were investigated to perform the separation. Hydroxides of iron (III), manganese (II), cobalt (II, III), and chromium (III); manganese (IV) oxide, and sodium uranate were investigated as carriers. The report describes the optimum conditions that were identified to precipitate these carriers homogeneously throughout the solution by reductive, hydrolytic, or catalytic decomposition of alkali-soluble precursor compounds by a technique called the Method of Appearing Reagents. The coprecipitation of pentavalent and hexavalent neptunium and plutonium was investigated for the candidate agents under optimum conditions and is described in this report along with the following results. Plutonium coprecipitated well with all tested materials except manganese (IV) oxide. Neptunium only coprecipitated well with uranate. The report presents a hypothesis to explain these behaviors. Further tests with more complex solution matrices must be performed.

  5. Treatment of infectious skin defects or ulcers with electrolyzed strong acid aqueous solution.

    Science.gov (United States)

    Sekiya, S; Ohmori, K; Harii, K

    1997-01-01

    A chronic ulcer with an infection such as methicillin-resistant Staphylococcus aureus is hard to heal. Plastic and reconstructive surgeons often encounter such chronic ulcers that are resistant to surgical or various conservative treatments. We applied conservative treatment using an electrolyzed strong acid aqueous solution and obtained satisfactory results. The lesion was washed with the solution or soaked in a bowl of the solution for approximately 20 min twice a day. Fresh electrolyzed strong acid aqueous solution is unstable and should be stored in a cool, dark site in a sealed bottle. It should be used within a week after it has been produced. Here we report on 15 cases of infectious ulcers that were treated by electrolyzed strong acid aqueous solution. Of these cases, 7 patients were healed, 3 were granulated, and in 5, infection subsided. In most cases the lesion became less reddish and less edematous. Discharge or foul odor from the lesion was decreased. Electrolyzed strong acid aqueous solution was especially effective for treating a chronic refractory ulcer combined with diabetes melitus or peripheral circulatory insufficiency. This clinically applied therapy of electrolyzed strong acid aqueous solution was found to be effective so that this new therapeutic technique for ulcer treatment can now be conveniently utilized.

  6. Investigation into formation of nanoparticles of tetravalent neptunium in slightly alkaline aqueous solution

    International Nuclear Information System (INIS)

    Husar, Richard

    2015-01-01

    Considering the worldwide growing discharge of minor actinides and the current need for geological disposal facilities for radioactive waste, this work provides a contribution to the safety case concerning Np transport if it would be released from deep repository sites and moving from alkaline cement conditions (near-field) to more neutral environmental conditions (far-field). The reducing conditions in a nuclear waste repository render neptunium tetravalent, which is assumed to be immobile in aqueous environment due to the low solubility solution of Np(IV). For tetravalent actinide nuclides, the most significant transport should occur via colloidal particles. This work demonstrates the formation of intrinsic neptunium dioxide nanocrystals and amorphous Np(IV) silica colloids under environmentally relevant conditions. The dissociation of the initial soluble Np(IV) complex (i.e. [Np(IV)(CO 3 ) 5 ] 6- ) induces the intrinsic formation of nanocrystalline NpO 2 in the solution phase. The resulting irregularly shaped nanocrystals with an average size of 4 nm exhibit a face-centered cubic (fcc), fluorite-type structure (space group Fm anti 3m). The NCs tend to agglomerate under ambient conditions due to the weakly charged hydrodynamic surface at neutral pH (zetapotential ζ ∝0 mV). The formation of micron-sized agglomerates, composed of nanocrystals of 2-5 nm in size, and the subsequent precipitation cause immobilization of the major amount of Np(IV) in the Np carbonate system. Agglomeration of NpO 2 nanocrystals in dependence on time was indicated by PCS and UV-vis absorption spectroscopy with the changes of baseline characteristics and absorption maximum at 742 nm. Hitherto, unknown polynuclear species as intermediate species of NpO 2 nanocrystal formation were isolated from solution and observed by HR-TEM. These polynuclear Np species appear as dimers, trimers and hexanuclear compounds in analogy with those reported for other actinides. Intrinsic formation of NpO 2

  7. Impacts of anions on the oxygen reduction reaction kinetics on platinum and palladium surfaces in alkaline solutions.

    Science.gov (United States)

    Zhu, Shangqian; Hu, Xiaomeng; Shao, Minhua

    2017-03-15

    The fundamental understanding of the impacts induced by anions on oxygen reduction reaction (ORR) in alkaline media is of great importance in the design of more advanced catalysts for alkaline fuel cells (AFC). In this study, the specific adsorption of F - , Cl - , ClO 4 - , CO 3 2- , SO 4 2- , and citrate anions on Pt/C and Pd/C catalysts, and their impacts on the ORR kinetics in alkaline solutions were systematically studied. It was found that F - , Cl - and ClO 4 - did not specifically adsorb on Pt or Pd surfaces and had no poisoning effect on ORR. CO 3 2- and SO 4 2- had significant effects on Pt/C and lowered the activity even at a very low concentration. On the other hand, their impacts on Pd/C were negligible. Self-dissociation of citrate anions was found to occur on both Pt/C and Pd/C in the H adsorption/desorption and double layer regions. For the first time, surface enhanced infrared absorption spectroscopy (SEIRAS) with the attenuated total reflection (ATR) technique was used to investigate the self-dissociation of citrate on Pt and Pd thin film electrodes. The breaking of carboxylic groups and the carbon backbone was proposed as a possible dissociation pathway for citrate. The adsorbed species have a negligible effect on ORR activity on Pt/C as they are removed by oxidation before 0.75 V. In contrast, their oxidation on Pd/C surfaces is not completed until 0.91 V, which causes a lower ORR activity observed in rotating disk electrode measurements. The findings in this paper emphasize the importance of specific adsorption of anions and double-layer interfacial effects on the ORR activity measurement in alkaline solutions.

  8. The role of chelating agents on the corrosion mechanisms of aluminium in alkaline aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, D. [Centre d' Etudes de Chimie Metallurgique, CNRS, 15 rue Georges Urbain, 94407 Vitry Cedex (France); Barthes-Labrousse, M.-G. [Centre d' Etudes de Chimie Metallurgique, CNRS, 15 rue Georges Urbain, 94407 Vitry Cedex (France)], E-mail: marie-genevieve.barthes@u-psud.fr

    2009-02-15

    The influence of 1,2-diaminoethane (DAE) on the mechanism of aluminium corrosion in KOH solutions at pH 13 was investigated by combining time-resolved inductively coupled plasma optical emission spectrocopy, open-circuit potential measurements and X-ray photoelectron spectroscopy. In pure KOH solutions, a very slow corrosion rate is initially observed, corresponding to the dissolution of the native oxide layer. Following this incubation stage, the corrosion rate is increasing due to the formation and oxidation of Al hydride, until a steady state is reached. DAE behaves as a strong initial corrosion accelerator, due to synergistic effects with hydroxyl ions and a dissolution mechanism in three successive steps has been proposed: (i) a rapid initial dissolution induced by the formation and detachment from the surface of bidentate (chelate) Al-DAE metal bound surface complexes; (ii) a slower step ascribed to the formation and release of monodentate Al-DAE metal bound surface complexes and (iii) a final step dominated by direct oxidation of surface aluminium hydride by hydroxyl species as in pure KOH.

  9. CO adsorption and kinetics on well-characterized Pd films on Pt( 1 1 1 ) in alkaline solutions

    Science.gov (United States)

    Arenz, M.; Stamenkovic, V.; Schmidt, T. J.; Wandelt, K.; Ross, P. N.; Markovic, N. M.

    2002-05-01

    The electrochemistry of CO on a bare Pt(1 1 1) electrode as well as a Pt(1 1 1) electrode modified with pseudomorphic thin palladium films has been studied in alkaline solution by means of Fourier transform infrared (FTIR) spectroscopy. First Pd films were prepared and well characterized in ultra high vacuum and subsequently transferred into the electrochemical cell for the registration of the voltammetric profiles. The charge corresponding to the formation of underpotentially deposited hydrogen (H upd) on these Pt(1 1 1)- xPd surfaces was established in sulfuric acid solution as a function of x (0⩽ x⩽1 Pd monolayer (ML)). All subsequent measurements were then performed on electrochemically deposited palladium films using the above H upd charge vs. Pd coverage relationship to evaluate the amount of electrochemically deposited palladium. FTIR spectra for CO adsorbed on 1 ML and a submonolayer coverage are compared to those of the unmodified Pt(1 1 1) surface, all surfaces having identical 2D lattice structures. Infrared absorption bands of CO bound on either Pt(1 1 1) or Pt(1 1 1)-1 ML Pd are clearly distinguished. Spectra of CO adsorbed on Pd submonolayers show characteristic features of both CO bound to Pt and to Pd, indicating that on Pt(1 1 1)- xPd surfaces there is no coupling between Pt-CO ad and Pd-CO ad molecules. The kinetics of CO oxidation on these surfaces is determined either by rotating disk electrode measurements or by FTIR spectroscopy, monitoring the CO 32- production. The oxidation of CO ad on Pt(1 1 1) and on Pd modified platinum surfaces starts at the same potential, at ≈0.2 V. The oxidation rate is, however, considerably lower on the Pt(1 1 1)- xPd surfaces than on the Pt(1 1 1) surface. The kinetics of CO oxidation appears to be determined by the nature of adsorbed hydroxyl anions (OH ad), which are more strongly (less active) adsorbed on the highly oxophilic Pd atoms.

  10. Evidence for the Formation of Benzacridine Derivatives in Alkaline-Treated Sunflower Meal and Model Solutions

    Directory of Open Access Journals (Sweden)

    Verena Bongartz

    2016-01-01

    Full Text Available Sunflower extraction meal (SEM is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO. Several green trihydroxy benzacridine (TBA derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects.

  11. Copper and brass aged at open circuit potential in slightly alkaline solutions

    International Nuclear Information System (INIS)

    Procaccini, R.; Vazquez, M.; Cere, S.

    2009-01-01

    Surface oxide films were grown on 99.99% copper and brass (copper-zinc alloy, Cu77Zn21Al2) in 0.1 mol L -1 borax solution at open circuit potential and were characterized using various experimental techniques. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. The thickness of the oxide layers on copper and brass was compared by chronopotentiometric curves and potentiodynamic reductions. The electrical properties of each oxide were analyzed by means of electrochemical impedance spectroscopy. Their influence on the oxygen reduction reaction was also investigated using voltammetry hydrodynamic tools such as the rotating disk electrode. The results show that the incorporation of Zn to Cu in brass changes the composition and the thickness of the surface film. The films grown on brass tend to be thicker but less resistive and Zn compounds incorporate to the film. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction is strongly inhibited on oxidized electrodes, particularly in the case of brass. The global number of exchanged electrons remains close to four and seems to be independent of the presence of surface oxides.

  12. Bentonite reactivity in alkaline solutions: results of the Cyprus natural analogue project (CNAP)

    International Nuclear Information System (INIS)

    Alexander, W.R.; Milodowski, A.E.; Pitty, A.F.; Hardie, S.M.L.; Korkeakoski, P.; Norris, S.; Puigdomenech, I.; Sellin, P.; Rigas, M.

    2012-01-01

    Document available in extended abstract form only. Bentonite is one of the most safety-critical components of the engineered barrier system in the disposal concepts developed for many types of radioactive waste. Bentonite is used due to its favourable properties (including plasticity, swelling capacity, colloid filtration, low hydraulic conductivity, high retardation of key radionuclides) and its stability in relevant geological environments. However, bentonite is unstable under alkaline conditions and, due to the fact that cementitious materials react with groundwater to produce initial leachates with pH >13 (later falling to around pH 12.5), this has driven recent interest in low alkali cements, because the pH of the leachate is somewhat lower than standard OPC (Ordinary Portland Cement), lying around pH 10-11. It is hoped that this lower pH will reduce bentonite reaction, so allowing the use of low alkali cements in close proximity with bentonite. Assuring the long-term stability of bentonite in contact with such alkaline fluids under conditions representative of a deep geological repository requires complementary laboratory, modelling and in situ studies. In particular, to build a robust safety case, it is important to have supporting natural analogue data to confirm understanding - and validate models - of the likely long-term performance of bentonite. As a result of a review of the available literature and recent geological investigations by the authors, several sites in Cyprus were selected as particularly promising for this purpose. All alkaline groundwaters studied so far in Cyprus originate from ophiolite host rocks which are wide-spread across the island. The alkaline pH values (generally between pH 10 and 11, but a maximum of 12 has been observed) reported in the groundwaters are a product of the serpentinization of the ophiolites. The presence of bentonite and other clay-rich rocks in close proximity to the natural alkaline groundwaters permits the

  13. Facile preparation of acid-resistant magnetite particles for removal of Sb(?) from strong acidic solution

    OpenAIRE

    Wang, Dong; Guan, Kaiwen; Bai, Zhiping; Liu, Fuqiang

    2016-01-01

    Abstract A new facile coating strategy based on the hydrophobicity of methyl groups was developed to prevent nano-sized magnetite particles from strong acid corrosion. In this method, three steps of hydrolysis led to three layers of protection shell coating Fe3O4 nanoparticles. Filled with hydrophobic methyl groups, the middle layer mainly prevented the magnetic core from strong acid corrosion. These magnetite particles managed to resist 1 M HCl solution and 2.5 M H2SO4 solution. The acid res...

  14. Description of the magnetic properties of strongly correlated disordered solid solutions in the coherent potential approximation

    Science.gov (United States)

    Korotin, M. A.; Skorikov, N. A.

    2015-06-01

    A method for electronic structure calculations of strongly correlated materials based on the coherent potential approximation is formulated and implemented. Method is applied for investigation of the electronic structure and local magnetic moments of the strongly correlated systems with d- and f-electrons: NiO-ZnO solid solution, nonstoichiometric perovskite LaMnO3-x, doped compound TiO2:Fe, and rare-earth transition-metal intermetallic compound GdNi2:Mn.

  15. Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

    International Nuclear Information System (INIS)

    Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Lassinantti Gualtieri, Magdalena; Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Romagnoli, Marcello; Pollastri, Simone; Gualtieri, Alessandro F.

    2015-01-01

    Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed

  16. Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

    Energy Technology Data Exchange (ETDEWEB)

    Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Romagnoli, Marcello [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Pollastri, Simone; Gualtieri, Alessandro F. [Dipartimento di Scienze Chimiche e Geologiche, Università degli studi di Modena e Reggio Emilia, Via S. Eufemia 19I, I-41121 Modena (Italy)

    2015-01-15

    Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed.

  17. Durability of template-free Fe-N-C foams for electrochemical oxygen reduction in alkaline solution

    Science.gov (United States)

    Mufundirwa, Albert; Harrington, George F.; Smid, Břetislav; Cunning, Benjamin V.; Sasaki, Kazunari; Lyth, Stephen M.

    2018-01-01

    Due to the high cost and limited availability of platinum, the development of non-platinum-group metals (non-PGM) catalysts is of paramount importance. A promising alternative to Pt are Fe-N-C-based materials. Here we present the synthesis, characterization and electrochemistry of a template-free nitrogen-doped carbon foam, impregnated with iron. This low-cost and gram-scale method results in materials with micron-scale pore size and large surface area (1600 m2g-1). When applied as an oxygen reduction reaction (ORR) electrocatalyst in alkaline solution, the Fe-N-C foams display extremely high initial activity, slightly out-performing commercially available non-PGM catalysts (NCP-2000, Pajarito Powder). The load-cycle durability in alkaline solution is investigated, and the performance steadily degrades over 60,000 potential cycles, whilst the commercial catalyst is remarkably stable. The post-operation catalyst microstructure is elucidated by transmission electron microscopy (TEM), to provide insight into the degradation processes. The resulting images suggest that potential cycling leads to leaching of atomically dispersed Fe-N2/4 sites in all the catalysts, whereas encapsulated iron nanoparticles are protected.

  18. Study of the alloying additives and alkaline zincate solution effects on the commercial aluminum as galvanic anode for use in alkaline batteries

    International Nuclear Information System (INIS)

    Rashvand avei, M.; Jafarian, M.; Moghanni Bavil Olyaei, H.; Gobal, F.; Hosseini, S.M.; Mahjani, M.G.

    2013-01-01

    The corrosion behavior of different grades of commercial aluminum such as AA1040, AA5083, AA6060 and AA7075 in ZnO-containing 4 M NaOH has been determined by using open circuit potential-time measurements (OCP), galvanostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) reveal that ZnO produces the inhibition effect by the formation of a zinc-containing deposit layer on the surface of aluminum electrodes. Although the influence of zincating on the performance of aluminum alloys and considering the amount of alloying elements such as zinc, magnesium and manganese in AA7075 and AA5083 alloys is much more than AA6060 one, the AA6060 aluminum exhibits negligible corrosion rate. Alloying aluminum with other elements and modifying the composition of the electrolyte is a necessary condition for reducing the self-corrosion of the aluminum anodes, whereas the proportion of the amount of additive elements is sufficient and important condition. As AA6060 with a low amount of Zn and Mg, but the high value of the ratio of (Mg/Zn) content (>400) can serve as a good galvanic anode in the alkaline media. - Highlights: • Decreasing the corrosion rate of tested alloys in 4 M NaOH solution specially AA6060. • Lowering the extent of anodic polarization at a current density of 50 mA cm −2 . • High inhibitor efficiency about 97% for AA6060

  19. Dissolution Mechanism of Wollastonite in Alkaline Solutions in Relation to Other Ca- and Mg-Bearing Pyroxenes

    Science.gov (United States)

    Halder, S.; Walther, J. V.

    2011-12-01

    Sougata Halder, Schlumberger Data & Consulting Services, 1325 S. Dairy Ashford, Houston, Texas 77077, shalder@slb.com and John V. Walther, Department of Earth Sciences, Southern Methodist University, P.O. Box 750395, Dallas, TX-75275, walther@smu.edu. This study is a comparison of alkaline dissolution rates of wollastonite with those of diopside and enstatite under similar experimental conditions. Far from equilibrium wollastonite dissolution rates both open to atmospheric CO2 and CO2-purged were measured as a function of solution pH from 8 to 13 in batch reactors at room temperature. Steady-state dissolution rates of wollastonite decrease with increase in pH throughout the pH range. Steady-state dissolution rates of CO2-purged experiments are similar, within the experimental uncertainties, to the open to atmospheric CO2 dissolution rates. This indicates the decrease in rates with increasing pH is not controlled by surface carbonate complexation as proposed for our diopside and enstatite dissolution studies under similar conditions (Halder and Walther, in press). The absence of a rate minimal close to the pHZPC of wollastonite as observed in the present study points to a dissolution mechanism not controlled directly by the quantity of adsorbed H+ or OH- on the mineral surface. We believe that the dissolution of wollastonite takes place in two distinct steps. The first step is proton-Ca exchange at the mineral surface that partially liberates silica tetrahedral chains of wollastonite, followed by the breaking of Si-O bonds within the tetrahedral chains. In these experiments adsorption of solution carbonate to the positively charged Ca surface sites below the pHZPC of CaO is thought to be inhibited by the lack of Ca on the surface produced by rapid Ca-proton exchange during the first step of dissolution of wollastonite. This also points to a different mechanism of dissolution of the pyroxenoid, wollastonite, in comparison to the dissolution of Ca and/or Mg bearing

  20. Influence of Experimental Parameters Using the Dip-Coating Method on the Barrier Performance of Hybrid Sol-Gel Coatings in Strong Alkaline Environments

    Directory of Open Access Journals (Sweden)

    Rita B. Figueira

    2015-04-01

    Full Text Available Previous studies have shown that the barrier effect and the performance of organic-inorganic hybrid (OIH sol-gel coatings are highly dependent on the coating deposition method as well as on the processing conditions. However, studies on how the coating deposition method influences the barrier properties in alkaline environments are scarce. The aim of this experimental research was to study the influence of experimental parameters using the dip-coating method on the barrier performance of an OIH sol-gel coating in contact with simulated concrete pore solutions (SCPS. The influence of residence time (Rt, a curing step between each dip step and the number of layers of sol-gel OIH films deposited on hot-dip galvanized steel to prevent corrosion in highly alkaline environments was studied. The barrier performance of these OIH sol-gel coatings, named U(400, was assessed in the first instants of contact with SCPS, using electrochemical impedance spectroscopy and potentiodynamic methods. The durability and stability of the OIH coatings in SCPS was monitored during eight days by macrocell current density. The morphological characterization of the surface was performed by Scanning Electronic Microscopy before and after exposure to SCPS. Glow Discharge Optical Emission Spectroscopy was used to investigate the thickness of the U(400 sol-gel coatings as a function of the number of layers deposited with and without Rt in the coatings thickness.

  1. Titanium Nitride Nanoparticle Electrocatalysts for Oxygen Reduction Reaction in Alkaline Solution

    KAUST Repository

    Ohnishi, R.

    2013-03-12

    Monodispersed TiN nanoparticles with a narrow size distribution (7–23 nm) were synthesized using mesoporous graphitic (mpg)-C3N4 templates with different pore sizes. The nano-materials were examined as electrocatalysts for oxygen reduction reaction (ORR) in alkaline media. The TiN nanoparticles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 sorption, transmission electron microscopy (TEM), and C-H-N elemental analysis. The ORR current increased as the TiN particle size decreased, and hence the surface area of TiN nanoparticles reactive to ORR increased. Rotating ring disk electrode (RRDE) measurements revealed that the ORR on TiN surfaces proceeded mainly via a two-electron pathway, producing H2O2 as the main product. Mechanistic aspects of ORR on TiN surfaces are discussed.

  2. Reductive atmospheric acid leaching of spent alkaline batteries in H2SO4/Na2SO3 solutions

    Science.gov (United States)

    Morcali, Mehmet Hakan

    2015-07-01

    This work studies the optimum reductive leaching process for manganese and zinc recovery from spent alkaline battery paste. The effects of reducing agents, acid concentration, pulp density, reaction temperature, and leaching time on the dissolution of manganese and zinc were investigated in detail. Manganese dissolution by reductive acidic media is an intermediate-controlled process with an activation energy of 12.28 kJ·mol-1. After being leached, manganese and zinc were selectively precipitated with sodium hydroxide. The zinc was entirely converted into zincate (Zn(OH){4/2-}) ions and thus did not co-precipitate with manganese hydroxide during this treatment (2.0 M NaOH, 90 min, 200 r/min, pH > 13). After the manganese was removed from the solution, the Zn(OH){4/2-} was precipitated as zinc sulfate in the presence of sulfuric acid. The results indicated that this process could be effective in recovering manganese and zinc from alkaline batteries.

  3. Electrochemistry in aqueous solution at high temperature and under pressure: study of nickel in a highly alkaline environment

    International Nuclear Information System (INIS)

    Forestier, Michel

    1981-01-01

    This research thesis reports the study of the corrosion resistance and anodic behaviour of various metals and alloys used in conventional thermal or nuclear power stations, more particularly the case of nickel in a highly alkaline environment (KOH 5 N) which is widely used for hydrogen production by water electrolysis. The author studied the influence of temperature and pressure on the electrochemical behaviour of nickel, and more particularly the first-oxidation kinetics. The report discusses the physicochemical and thermodynamic properties of aqueous systems at high temperature and under pressure, presents the general techniques of high-temperature electrochemistry, describes the experimental installation, and reports the development of a reference electrode which can operate in those experimental conditions. The author reports the study of the electrochemical behaviour of nickel in alkaline environment and at high temperature, reports a surface analysis performed by Auger spectroscopy, electron spectroscopy for chemical analysis or ESCA, and scanning electronic microscopy, reports the study of the electrochemical behaviour of nickel in a potassium hydroxide solution under normal temperature and pressure, but also in acid environment. Results are interpreted with respect to temperature [fr

  4. Study of hydrated electron reversible reaction with bivalent zinc in alkaline solutions by the method of pulsed radiolysis

    International Nuclear Information System (INIS)

    Gogolev, A.V.; Makarov, I.E.; Pikaev, A.K.

    1981-01-01

    Using the method of pulsed radiolysis the reversible Zn(2)+esub(aq) reversible Zn(1) reaction in alkaline aqueous solutions is studied. The irradiation has been carried out by the electrons with the energy of 5 MeV; the impulse duration is 2.3 μs, the impulse current is up to 0.2 A. The rate constants of the direct (ksub(+)) and reverse (ksub(-)) reactions are measured. It is detected that Ksub(+) decreases from (1.4+-0.2)x10 7 up to (3.8+-0.5)x10 6 l/molxs when the OH - concentration increases from 1 to 5M whereas the Ksub(-) value in the above [OH - ] range is constant and constitutes (4.3+-0.7)x10 6 s -1 . Effect of [OH - ] upon the value of ksub(+) is explained by the existence of Zn (2) in alkaline medium in different hydroxoforms Zn (OH) 3 - and ZN(OH) 4 - and by the dependence of their relative content on [OH - ]. The Ksub(+) values calculated for Zn(OH) 3 - and Zn(OH) 4 2- are equal to (2.7+-0.5)x10 8 and (1.2+-0.25)x10 6 l/molxs respectively

  5. Recent studies of uranium and plutonium chemistry in alkaline radioactive waste solutions

    International Nuclear Information System (INIS)

    King, William D.; Wilmarth, William R.; Hobbs, David T.; Edwards, Thomas B.

    2008-01-01

    Solubility studies of uranium and plutonium in a caustic, radioactive Savannah River Site tank waste solution revealed the existence of uranium supersaturation in the as-received sample. Comparison of the results to predictions generated from previously published models for solubility in these waste types revealed that the U model poorly predicts solubility while Pu model predictions are quite consistent with experimental observations. Separate studies using simulated Savannah River Site evaporator feed solution revealed that the known formation of sodium aluminosilicate solids in waste evaporators can promote rapid precipitation of uranium from supersaturated solutions

  6. CO{sub 2} absorption characteristics of a jet loop reactor with a two-fluid swirl nozzle in an alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Go-Eun; Lim, Jun-Heok; Lee, Tae-Yoon; Lee, Jea-Keun [Pukyong National University, Busan (Korea, Republic of); Sung, Ho-Jin [Institute for Advanced Engineering, Yongin (Korea, Republic of)

    2014-04-15

    To investigate the performance of a jet loop reactor with the two-fluid swirl nozzle (TSN), CO{sub 2} absorption experiments in an alkaline solution were performed. The experimental results obtained in the reactor were compared with those in a jet loop reactor with the two-fluid conventional nozzle (TCN). The neutralization time of alkaline solution and the CO{sub 2} removal efficiency were used as the indices for a comparison of the reactor performance. Due to the swirling flow, the neutralization times of alkaline solutions by CO{sub 2} in the reactor with the TSN were shortened compared with those in the reactor with the TCN. Also, the instantaneous and/or overall CO{sub 2} removal efficiencies in the reactor with the TSN were higher than those in the reactor with the TCN at the same liquid circulation flow rate.

  7. Solutions to the strong-CP problem in a world with gravity

    International Nuclear Information System (INIS)

    Holman, R.; Watkins, R.; Widrow, L.M.; Toronto Univ., ON

    1992-01-01

    We examine various solutions of the strong-CP problem to determine their sensitivity to possible violations of global symmetries by Plauck scale physics. While some solutions remain viable even in the face of such effects. Violations of the Peccei-Quinn (PQ) symmetry by non-renormalizable operators of dimension less than 10 will generally shift the value of bar θ to values inconsistent with the experimental bound bar θ approx-lt 10 - 9. We show that it is possible to construct axion models where gauge symmetries protect PQ symmetry to the requisite level

  8. On the kinetics of the hydrogen evolution reaction on Ni-MoOx composite catalysts in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Jović Borka M.

    2012-01-01

    Full Text Available MoO3 particles were co-deposited with Ni onto smooth or rough Ni supports from modified Watt’s baths of different compositions. Morphology and composition of the electrodeposits were characterized by means of cyclic voltammetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic activity of the composite catalysts for H2 evolution in alkaline solutions was determined by quasi-stationary polarization curves. Activity increases with MoOx content in the Ni deposit up to a limiting value. Composite Ni-MoOx catalyst performed high catalytic activity, similar to that of commercial Ni-RuO2 catalyst. Stability tests showed that Ni-MoOx codeposits are stable under condition of constant current and exhibit excellent tolerance to repeated short-circuiting.

  9. Hydrophilic cobalt sulfide nanosheets as a bifunctional catalyst for oxygen and hydrogen evolution in electrolysis of alkaline aqueous solution.

    Science.gov (United States)

    Zhu, Mingchao; Zhang, Zhongyi; Zhang, Hu; Zhang, Hui; Zhang, Xiaodong; Zhang, Lixue; Wang, Shicai

    2018-01-01

    Hydrophilic medium and precursors were used to synthesize a hydrophilic electro-catalyst for overall water splitting. The cobalt sulfide (Co 3 S 4 ) catalyst exhibits a layered nanosheet structure with a hydrophilic surface, which can facilitate the diffusion of aqueous substrates into the electrode pores and towards the active sites. The Co 3 S 4 catalyst shows excellent bifunctional catalytic activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline solution. The assembled water electrolyzer based on Co 3 S 4 exhibits better performance and stability than that of Pt/C-RuO 2 catalyst. Thereforce the hydrophilic Co 3 S 4 is a highly promising bifunctional catalyst for the overall water splitting reaction. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Decomposition of N-chloroglycine in alkaline aqueous solution: kinetics and mechanism.

    Science.gov (United States)

    Szabó, Mária; Baranyai, Zsolt; Somsák, László; Fábián, István

    2015-06-15

    The decomposition kinetics and mechanism of N-chloroglycine (MCG) was studied under very alkaline conditions ([OH(-)] = 0.01-0.10 M). The absorbance change is consistent with two consecutive first-order processes in the 220-350 nm wavelength range. The first reaction is linearly dependent on [OH(-)] and interpreted by the formation of a carbanion from MCG in an equilibrium step (KOH) and a subsequent loss of chloride ion from this intermediate: kobs1 = KOH k1 = (6.4 ± 0.1) × 10(-2) M(-1) s(-1), I = 1.0 M (NaClO4), and T = 25.0 °C. The second process is assigned to the first-order decomposition of N-oxalylglycine, which is also formed as an intermediate in this system: kobs2 = (1.2 ± 0.1) × 10(-3) s(-1). Systematic (1)H and (13)C NMR measurements were performed in order to identify and follow the concentration changes of the reactant, intermediate, and product. It is confirmed that the decomposition proceeds via the formation of glyoxylate ion and produces N-formylglycine as a final product. This compound is stable for an extended period of time but eventually hydrolyses into formate and glycinate ions. A detailed mechanism is postulated which resolves the controversies found in earlier literature results.

  11. Development of Cobalt Hydroxide as a Bifunctional Catalyst for Oxygen Electrocatalysis in Alkaline Solution.

    Science.gov (United States)

    Zhan, Yi; Du, Guojun; Yang, Shiliu; Xu, Chaohe; Lu, Meihua; Liu, Zhaolin; Lee, Jim Yang

    2015-06-17

    Co(OH)2 in the form of hexagonal nanoplates synthesized by a simple hydrothermal reaction has shown even greater activity than cobalt oxides (CoO and Co3O4) in oxygen reduction and oxygen evolution reactions (ORR and OER) under alkaline conditions. The bifunctionality for oxygen electrocatalysis as shown by the OER-ORR potential difference (ΔE) could be reduced to as low as 0.87 V, comparable to the state-of-the-art non-noble bifunctional catalysts, when the Co(OH)2 nanoplates were compounded with nitrogen-doped reduced graphene oxide (N-rGO). The good performance was attributed to the nanosizing of Co(OH)2 and the synergistic interaction between Co(OH)2 and N-rGO. A zinc-air cell assembled with a Co(OH)2-air electrode also showed a performance comparable to that of the state-of-the-art zinc-air cells. The combination of bifunctional activity and operational stability establishes Co(OH)2 as an effective low-cost alternative to the platinum group metal catalysts.

  12. Local strong solutions to the stochastic compressible Navier-Stokes system

    Czech Academy of Sciences Publication Activity Database

    Breit, D.; Feireisl, Eduard; Hofmanová, M.

    2018-01-01

    Roč. 43, č. 2 (2018), s. 313-345 ISSN 0360-5302 EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : compressible fluids * local strong solution s * Navier-Stokes system Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.608, year: 2016 https://www.tandfonline.com/doi/full/10.1080/03605302.2018.1442476

  13. Local strong solutions to the stochastic compressible Navier-Stokes system

    Czech Academy of Sciences Publication Activity Database

    Breit, D.; Feireisl, Eduard; Hofmanová, M.

    2018-01-01

    Roč. 43, č. 2 (2018), s. 313-345 ISSN 0360-5302 EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : compressible fluids * local strong solutions * Navier-Stokes system Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.608, year: 2016 https://www.tandfonline.com/doi/full/10.1080/03605302.2018.1442476

  14. Strongly increasing solutions of cyclic systems of second order differential equations with power-type nonlinearities

    Directory of Open Access Journals (Sweden)

    Jaroslav Jaroš

    2015-01-01

    Full Text Available We consider \\(n\\-dimensional cyclic systems of second order differential equations \\[(p_i(t|x_{i}'|^{\\alpha_i -1}x_{i}'' = q_{i}(t|x_{i+1}|^{\\beta_i-1}x_{i+1},\\] \\[\\quad i = 1,\\ldots,n, \\quad (x_{n+1} = x_1 \\tag{\\(\\ast\\}\\] under the assumption that the positive constants \\(\\alpha_i\\ and \\(\\beta_i\\ satisfy \\(\\alpha_1{\\ldots}\\alpha_n \\gt \\beta_1{\\ldots}\\beta_n\\ and \\(p_i(t\\ and \\(q_i(t\\ are regularly varying functions, and analyze positive strongly increasing solutions of system (\\(\\ast\\ in the framework of regular variation. We show that the situation for the existence of regularly varying solutions of positive indices for (\\(\\ast\\ can be characterized completely, and moreover that the asymptotic behavior of such solutions is governed by the unique formula describing their order of growth precisely. We give examples demonstrating that the main results for (\\(\\ast\\ can be applied to some classes of partial differential equations with radial symmetry to acquire accurate information about the existence and the asymptotic behavior of their radial positive strongly increasing solutions.

  15. Coloring Rate of Phenolphthalein by Reaction with Alkaline Solution Observed by Liquid-Droplet Collision.

    Science.gov (United States)

    Takano, Yuuka; Kikkawa, Shigenori; Suzuki, Tomoko; Kohno, Jun-ya

    2015-06-11

    Many important chemical reactions are induced by mixing two solutions. This paper presents a new way to measure rates of rapid chemical reactions induced by mixing two reactant solutions using a liquid-droplet collision. The coloring reaction of phenolphthalein (H2PP) by a reaction with NaOH is investigated kinetically. Liquid droplets of H2PP/ethanol and NaOH/H2O solutions are made to collide, which induces a reaction that transforms H2PP into a deprotonated form (PP(2-)). The concentration of PP(2-) is evaluated from the RGB values of pixels in the colored droplet images, and is measured as a function of the elapsed time from the collision. The obtained rate constant is (2.2 ± 0.7) × 10(3) M(-1) s(-1), which is the rate constant for the rate-determining step of the coloring reaction of H2PP. This method was shown to be applicable to determine rate constants of rapid chemical reactions between two solutions.

  16. Assessment of the Effects Exerted by Acid and Alkaline Solutions on Bone: Is Chemistry the Answer?

    Science.gov (United States)

    Amadasi, Alberto; Camici, Arianna; Porta, Davide; Cucca, Lucia; Merli, Daniele; Milanese, Chiara; Profumo, Antonella; Rassifi, Nabila; Cattaneo, Cristina

    2017-09-01

    The treatment of corpses with extremely acid or basic liquids is sometimes performed in criminal contexts. A thorough characterization by chemical analysis may provide further help to macroscopic and microscopic analysis; 63 porcine bone samples were treated with solutions at different pH (1-14) for immersion periods up to 70 days, as well as in extremely acidic sulfuric acid solutions (9 M/18 M) and extremely basic sodium hydroxide. Inductively coupled optical emission spectrometry (ICP-OES)/plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) showed that only the sulfuric acid solution 18 M was able to completely dissolve the sample. In addition, chemical analysis allowed to recognize the contact between bone and substances. Hydrated calcium sulfate arose from extreme pH. The possibility of detecting the presence of human material within the residual solution was demonstrated, especially with FT-IR, ICP-OES, and EDX. © 2017 American Academy of Forensic Sciences.

  17. Mechanical and electrochemical properties of an IPMC actuator with palladium electrodes in acid and alkaline solutions

    Science.gov (United States)

    Aoyagi, Wataru; Omiya, Masaki

    2013-05-01

    An ionic polymer-metal composite (IPMC) actuator, which consists of a thin perfluorinated ionomer membrane and electrodes plated on both surfaces, undergoes a large bending motion when a low electric field is applied across its thickness. IPMC actuators are lightweight and soft and can operate in solutions. They are thus promising for a wide range of applications including MEMS sensors, artificial muscles, biomimetic systems, and medical devices. The deformation behavior of IPMC actuators depends on the pH of the working solution. However, their basic mechanism is not well understood. Therefore, this study investigates the deformation mechanism of an IPMC actuator with palladium electrodes in various pH solutions. The tip displacements of IPMC actuators were measured under a step voltage in various pH solutions. Cyclic voltammetry (CV) and alternating-current (AC) impedance measurements were then performed to investigate the effects of pH on the electrochemical properties of IPMC actuators. The responses to a step voltage indicate that the deformation behavior of an IPMC actuator depends on the pH: a lower pH gives a larger maximum tip displacement and more pronounced relaxation. In CV measurements, a lower pH results in more active reduction on the palladium electrode. In AC impedance measurements, a lower pH leads to a greater charge transfer resistance and a smaller double layer capacitance in an acid solution. Based on these mechanical and electrochemical measurements, we conclude that the maximum tip displacement and relaxation are governed by reduction on the palladium electrode and that the residual tip displacement is related to the charge transfer resistance and the double layer capacitance. These results are helpful for the use and control of IPMC actuators.

  18. Formation of ammonia complexes of alkaline earth elements in aqueous solutions

    International Nuclear Information System (INIS)

    Padar, T.G.; Stupko, T.V.; Isaev, I.D.; Pashkov, G.L.; Mironov, V.E.

    1990-01-01

    Coefficients of ammonia distribution between aqueous solutions of calcium, strontium, barium and ammonium perchlorate mixtures at ionic strength - 0.50; 1.0 and 1.5 at 298.2 K and ammonia concentrations 0.2-10 mol/dm 3 are measured. Formation of ammonia complexes of M(NH 3 ) n 2+ composition is shown. Logarithms of stepped stability constants for solutions with zero ionic strength for Ca 2+ are: -0.13; -0.25; -0.52 and -0.77, where n=1-4; for Sr 2+ : -0.04; -0.42 and -0.70, where n=1-3 and for Ba 2+ : -0.11; -0.50 and 0.76, where n=1-3

  19. Determination of contents of carbonate and hydrogen carbonate in solutions for alkaline leading of uranium ores

    International Nuclear Information System (INIS)

    Radil, V.

    1988-01-01

    The new analytical method is based on the determination of the molar ratio carbonate - hydrogen carbonate using the measured concentration of hydrogen ions, the determination of the dissociation constant of carbonic acid for different values of ionic strength. The concentration of hydrogen ions was measured with a Metrohm 632 pH meter with the use of a combined glass electrode. The content of total carbonate carbon was determined coulometrically and the uranium content was determined by extraction with tributyl phosphate and by spectrometry of the complex of uranyl ions with Arsenazo III. Model solutions were used for the experiments which contained a high concentration of sulfate ions, thiosulfate ions, uranium and various proportions of carbonate and hydrogen carbonate. The composition of the individual samples of the extraction solutions are tabulated. The calibration was made of the glass combined electrode at different ionic strength, the values determined of dissociation constants of carbonic acid for different ionic strength. The mathematical procedure is described for the calculation of molar concentrations of carbonate and hudrogen carbonate and the results are presented of the analysis of model solutions. (E.S.). 5 tabs., 1 fig., 5 refs

  20. Ultrasonic Monitoring of the Interaction between Cement Matrix and Alkaline Silicate Solution in Self-Healing Systems

    Directory of Open Access Journals (Sweden)

    Mohand Ait Ouarabi

    2017-01-01

    Full Text Available Alkaline solutions, such as sodium, potassium or lithium silicates, appear to be very promising as healing agents for the development of encapsulated self-healing concretes. However, the evolution of their mechanical and acoustic properties in time has not yet been completely clarified, especially regarding their behavior and related kinetics when they are used in the form of a thin layer in contact with a hardened cement matrix. This study aims to monitor, using linear and nonlinear ultrasonic methods, the evolution of a sodium silicate solution interacting with a cement matrix in the presence of localized cracks. The ultrasonic inspection via linear methods revealed that an almost complete recovery of the elastic and acoustic properties occurred within a few days of healing. The nonlinear ultrasonic measurements contributed to provide further insight into the kinetics of the recovery due to the presence of the healing agent. A good regain of mechanical performance was ascertained through flexural tests at the end of the healing process, confirming the suitability of sodium silicate as a healing agent for self-healing cementitious systems.

  1. Solid-phase electrochemical reduction of graphene oxide films in alkaline solution.

    Science.gov (United States)

    Basirun, Wan J; Sookhakian, Mehran; Baradaran, Saeid; Mahmoudian, Mohammad R; Ebadi, Mehdi

    2013-09-24

    Graphene oxide (GO) film was evaporated onto graphite and used as an electrode to produce electrochemically reduced graphene oxide (ERGO) films by electrochemical reduction in 6 M KOH solution through voltammetric cycling. Fourier transformed infrared and Raman spectroscopy confirmed the presence of ERGO. Electrochemical impedance spectroscopy characterization of ERGO and GO films in ferrocyanide/ferricyanide redox couple with 0.1 M KCl supporting electrolyte gave results that are in accordance with previous reports. Based on the EIS results, ERGO shows higher capacitance and lower charge transfer resistance compared to GO.

  2. Strong convergence and convergence rates of approximating solutions for algebraic Riccati equations in Hilbert spaces

    Science.gov (United States)

    Ito, Kazufumi

    1987-01-01

    The linear quadratic optimal control problem on infinite time interval for linear time-invariant systems defined on Hilbert spaces is considered. The optimal control is given by a feedback form in terms of solution pi to the associated algebraic Riccati equation (ARE). A Ritz type approximation is used to obtain a sequence pi sup N of finite dimensional approximations of the solution to ARE. A sufficient condition that shows pi sup N converges strongly to pi is obtained. Under this condition, a formula is derived which can be used to obtain a rate of convergence of pi sup N to pi. The results of the Galerkin approximation is demonstrated and applied for parabolic systems and the averaging approximation for hereditary differential systems.

  3. No fragile-to-strong crossover in LiCl-H2O solution

    Science.gov (United States)

    Nakanishi, Masahiro; Griffin, Philip; Mamontov, Eugene; Sokolov, Alexei P.

    2012-03-01

    Dynamics of water, especially in the temperature range of the "no man's land", remain a mystery. We present detailed study of dynamics in aqueous LiCl solution that is often considered as a model for bulk water. We employ broadband dielectric and light scattering spectroscopy in a broad frequency and temperature range. Our analysis reveals no sign of the fragile-to-strong crossover (FSC) neither in structural relaxation nor in translational motions. Our experimental results combined with a large selection of literature data lead to the clear conclusion-there is no FSC in dynamics of aqueous solutions at T ˜ 200-230 K. Instead, our analysis reveals appearance of the so-called excess wing at the high frequency tail of the structural relaxation peak. We discuss the localized nature of the relaxation process that contributes to the excess wing.

  4. Strong cosmic censorship for solutions of the Einstein-Maxwell field equations with polarized Gowdy symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto; Rendall, Alan D [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2009-05-21

    A proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this, it is seen that the deep results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  5. Recovery of uranium from the Syrian phosphate by solid-liquid method using alkaline solutions

    International Nuclear Information System (INIS)

    Shlewit, H.; Alibrahim, M.

    2007-01-01

    Uranium concentrations were analyzed in the Syrian phosphate deposits. Mean concentrations were found between 50 and 110 ppm. As a consequence, an average phosphate dressing of 22 kg/ha phosphate would charge the soil with 5-20 g/ha uranium when added as a mineral fertilizer. Fine grinding phosphate produced at the Syrian mines was used for uranium recovery by carbonate leaching. The formation of the soluble uranyl tricarbonate anion UO 2 (CO 3 ) 3 4- permits use of alkali solutions of sodium carbonate and sodium bicarbonate salts for the nearly selective dissolution of uranium from phosphate. Separation of iron, aluminum, titanium, etc., from the uranium during leaching was carried out. Formation of some small amounts of molybdates, vanadates, phosphates, aluminates, and some complexes metal was investigated. This process could be used before the manufacture of TSP fertilizer, and the final products would contain smaller uranium quantities. (author)

  6. Extraction of some elements as oxygen-containing anions from alkaline solutions

    International Nuclear Information System (INIS)

    Dakar, G.M.; Iofa, B.Z.; Nesmeyanov, A.N.

    1976-01-01

    The extraction of rhenium (VII) from solutions of LiOH, NaOH, and KOH with ethyl, propyl, butyl, and amyl alcohols and methyl ethyl ketone, as well as the extraction of the alkalies themselves by the indicated organic solvents, were studied with the aid of radioactive tracers. With increasing alkali concentration in the aqueous phase, its distribution coefficient at first decreases, but then begins to rise. The alcohols, in contrast to the ketones, extract alkali hydroxides comparatively well (D approximately 0.1-0.5). Rhenium (VII) is well extracted by alcohols (D approximately 0.1-3) and by the ketone (D approximately 10-100). Perrhenic acid and its corresponding salt pass into the organic phase. The ratio of these compounds basically determines the form of the dependence of the distribution coefficients of rhenium(VII) on the alkali concentration in the aqueous phase. A measurement of the absorption spectra of the initial solutions, extracts, and refinates permitted us to conclude that in extraction the ketone passes into the inner coordination sphere of the perrhenate ion. In the extraction of rhenium(VII) by alcohols, there is a hydration and solvation both of the cationic and of the anionic portions of the associate. In the ketone HReO 4 dissociates appreciably, and therefore a decrease in the distribution coefficients of rhenium(VII) is observed as its concentration in the aqueous phase increases. In the case of alcohols, there is no such dependence, because the readily extractable alkalies suppress the dissociation of NaReO 4 in the organic phase

  7. Catalytic Activity of Urchin-like Ni nanoparticles Prepared by Solvothermal Method for Hydrogen Evolution Reaction in Alkaline Solution

    International Nuclear Information System (INIS)

    Abbas, Syed Asad; Iqbal, Muhammad Ibrahim; Kim, Seong-Hoon; Jung, Kwang-Deog

    2017-01-01

    Highlights: • Urchin-like Ni is prepared in solvothermal reaction. • Urchin-like Ni is formed via Ni(OH) 2 aggregates in ethanol and oleylamine. • Exchange current density of urchin-like Ni is 0.191 mA cm −2 . • Urchin-like Ni exceeds the catalytic performance of commercial Pt/C in HER. - Abstract: Ni nanoparticles with different morphologies were synthesized for hydrogen evolution reaction (HER) in alkaline solution. Here, Ni(acac) 2 was converted into Ni metal nanoparticles in solvothermal reactions with simple alcohols and oleylamine (OAm). The morphology of the resulting Ni nanoparticles was dependent mainly on the OAm/Ni molar ratio in alcohol solvent. Aggregates of spherical Ni nanoparticles (NiEt-OAm1) were observed at the OAm/Ni molar ratio of 1.0, whereas two echinoid Ni nanoparticles (NiEt-OAm4 and NiEt-OAm6) could be prepared in ethanol at the OAm/Ni molar ratios of 4.0 and 6.0. Ni(OH) 2 formed in ethanol during a reaction time of 5 h was then reduced into echinoid Ni nanoparticles after 8 h. Echinoid Ni nanoparticles were formed by atomic addition on the tops of the multipod Ni particles formed via Ni(OH) 2 /NiO aggregates. Webbed feet-like particles (NiIPA-OAm4) with plate edges were also observed in isopropanol under the same reaction conditions. The catalytic activities of the prepared Ni nanoparticles for the hydrogen evolution reaction were evaluated in alkaline solution. The NiEt-OAm4 with urchin-like morphology was much more active than the NiIPA-OAm4 with webbed feet-like morphology. The exchange current density of Ni catalysts was increased with increasing the OAm/Ni molar ratio. The NiEt-OAm6 exhibited an exchange current of 0.191 mA cm −2 and the NiEt-OAm4 exceeded electrocatalytic performance of a commercial Pt catalysts (40% Pt on Vulcan XC 72) in a stability test for 100 kiloseconds at −1.5 V (vs. Hg/HgO) in 1.0 M NaOH due to its high stability.

  8. The anodic dissolution of SIMFUEL (UO2) in slightly alkaline sodium carbonate/bicarbonate solutions

    International Nuclear Information System (INIS)

    Keech, P.G.; Goldik, J.S.; Qin, Z.; Shoesmith, D.W.

    2011-01-01

    The corrosion of nuclear fuel under waste disposal conditions is likely to be influenced by the bicarbonate/carbonate content of the groundwater since it increases the solubility of the U VI corrosion product, [UO 2 ] 2+ . As one of the half reactions involved in the corrosion process, the anodic dissolution of SIMFUEL (UO 2 ) has been studied in bicarbonate/carbonate solutions (pH 9.8) using voltammetric and potentiostatic techniques and electrochemical impedance spectroscopy. The reaction proceeds by two consecutive one electron transfer reactions (U IV → U V → U VI ). At low potentials (≤250 mV (vs. SCE) the rate of the first electron transfer reaction is rate determining irrespective of the total carbonate concentration. At potentials >250 mV (vs. SCE) the formation of a U VI O 2 CO 3 surface layer begins to inhibit the dissolution rate and the current becomes independent of potential indicating rate control by the chemical dissolution of this layer.

  9. Effect of Organic Inhibitors on Chloride Corrosion of Steel Rebars in Alkaline Pore Solution

    Directory of Open Access Journals (Sweden)

    Marina Cabrini

    2015-01-01

    Full Text Available The inhibition properties of aspartic and lactic acid salts are compared with nitrite ions with regard to their effect on critical chloride concentration. The tests were carried out on carbon steel specimens in simulated pore solutions with initial pH in the range of 12.6 to 13.8. The critical chloride concentrations were estimated through multiple specimen potentiostatic tests at potentials in the usual range for passive rebar in noncarbonated concrete structures. During tests, chloride ions were progressively added until all specimens showed localized attack, obtaining cumulative distribution curves reporting the fraction of corroded specimens as a function of chloride concentration. The presence of the organic inhibitors on the passivity film was detected by IR spectra. The results confirm that 0.1 M aspartate exhibits an inhibiting effect comparable with nitrite ions of the same concentration. Calcium lactate does not increase critical chloride concentration; however it appears to promote the formation of a massive scale, reducing the corrosion propagation.

  10. Substituent effects on the photophysical properties of pterin derivatives in acidic and alkaline aqueous solutions.

    Science.gov (United States)

    Cabrerizo, Franco M; Petroselli, Gabriela; Lorente, Carolina; Capparelli, Alberto L; Thomas, Andrés H; Braun, André M; Oliveros, Esther

    2005-01-01

    Pterins are heterocyclic compounds with important biological functions, and most of them may exist in two acid-base forms in the pH range between 3 and 13 in aqueous solution. In this work, the photophysical properties of acid and basic forms of six compounds of the pterin family (6-hydroxymethylpterin [HPT], 6-methylpterin [MPT], 6,7-dimethylpterin [DPT], rhamnopterin [RPT], N-methylfolic acid [MFA], and pteroic acid [PA]) have been studied. The effects of the chemical nature of the substituents at position 6 of the pterin moiety and the effects of the pH on the absorption and emission properties are analyzed. The fluorescence characteristics (spectra, quantum yields, lifetimes) of these compounds have been investigated using the single-photon-counting technique. Results obtained for pterin derivatives containing small substituents with 1 carbon atom (HPT, MPT, DPT) and short hydrocarbon chain (4 carbon atoms) (RPT) are different from those found for pterin derivatives containing a p-aminobenzoic acid (PABA) moiety in the substituent (MFA and PA). Fluorescence quantum yields (Phi(F)) of the first group of compounds are relatively high (>/=0.4), whereas MFA and PA exhibit very small Phi(F) values (

  11. Investigation on synergism of composite additives for zinc corrosion inhibition in alkaline solution

    International Nuclear Information System (INIS)

    Zhou Hebing; Huang Qiming; Liang Man; Lv Dongsheng; Xu Mengqing; Li Hong; Li Weishan

    2011-01-01

    Highlights: → An kind of environmentally benign organic composite additives is used firstly. → The corrosion of zinc is inhibited used the organic compound as additive. → The rate performance of the battery used the organic compound as additive is improved. → The synergism of composite additives for zinc corrosion inhibition is investigated. - Abstract: The synergism of imidazole (IMZ) and poly(ethylene glycol) 600 (PEG) for zinc corrosion inhibition in 3 mol L -1 KOH solution was investigated using a combination of electrochemical and gravimetric methods, and the surface morphology of the zinc was observed by scanning electron microscopy. It is found that there is a synergistic effect between IMZ and PEG for the zinc corrosion inhibition. The difference in molecular structure, ring for IMZ and chain for PEG, and in binding atoms with zinc, nitrogen in IMZ and oxygen in PEG, contributes to this synergistic effect. IMZ inhibits zinc corrosion by mainly depressing the anodic reaction, whereas PEG by depressing the cathodic reaction. The storage performance of the zinc-manganese dioxide batteries using IMZ and/or PEG as inhibitors was determined by discharge test, with a comparison of the battery using mercury as the inhibitor. The battery containing 0.05% IMZ + 0.05% PEG exhibits better performance than the mercury-containing battery, especially when discharged at high rate.

  12. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    International Nuclear Information System (INIS)

    Rothe, R.E.

    1996-01-01

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution's concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the 'Poisoned Tube Tank' because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service

  13. Heteromorphic NiCo2S4/Ni3S2/Ni Foam as a Self-Standing Electrode for Hydrogen Evolution Reaction in Alkaline Solution.

    Science.gov (United States)

    Liu, Hui; Ma, Xiao; Rao, Yuan; Liu, Yang; Liu, Jialiang; Wang, Luyang; Wu, Mingbo

    2018-04-04

    Considerable works have been devoted on developing high-efficiency nonplatinum electrocatalysts for hydrogen evolution reaction (HER). Herein, 3D heteromorphic NiCo 2 S 4 /Ni 3 S 2 nanosheets network has been constructed on Ni foam (denoted as NiCo 2 S 4 /Ni 3 S 2 /NF) serving as a self-standing electrocatalyst through directly thermal sulfurization of a single-source NiCo-layered double hydroxide precursor. The resultant NiCo 2 S 4 /Ni 3 S 2 /NF electrode exhibits outstanding electrocatalytic HER performance with an extremely low onset overpotential of 15 mV and long-term durability in alkaline solution. Such enhanced HER performance can be credited to (1) the massive exposed active sites provided by mixed transition metal chalcogenides (NiCo 2 S 4 and Ni 3 S 2 ), (2) the strong interfacial interaction at NiCo 2 S 4 /Ni 3 S 2 heterojunction interfaces with the strengthened H binding, and (3) the porous highly conductive Ni foam substrate with accelerated electron transfer. This work opens up a new direction to fabricate effective and non-noble-metal electrodes for water splitting and hydrogen generation.

  14. A study on zeolite precipitation at alkaline conditions: effect of solution composition on mineralogy and crystallization rate

    International Nuclear Information System (INIS)

    Francisco, P.C.M.; Nakabayashi, R.; Sato, T.

    2012-01-01

    Document available in extended abstract form only. Designs for engineered barrier systems for the geologic confinement of radioactive wastes involve the extensive use of bentonite, a material known for its capability to retard radionuclide migration into the groundwater system due to its low permeability. Cement and concrete are used in conjunction with bentonite to serve as structural supports and to seal access routes. However, when concrete becomes saturated with groundwater, it produces alkaline fluids that may attack and degrade the bentonite over time. A key concern regarding bentonite alteration by alkaline fluids is the precipitation of secondary minerals, such as zeolites, which may produce changes in the transport properties of the bentonite and compromise the stability of the entire barrier system. More importantly, studies have shown that zeolites form at timescales that are of interest in determining the long-term integrity of the barrier system. It is thus important to understand zeolite precipitation at conditions operative during bentonite alteration. The objective of this study, therefore, is to determine the effects of fluid composition on the crystallization rate and zeolite mineralogy. Zeolites were synthesized in batches from solutions with varying ratios of Si and Al at pH 13.5 by combining appropriate amounts of NaOH, NaAlO 2 and Na 2 SiO 3 .9H 2 O. The Si and Al concentrations in the starting solutions both ranged from 0.03 to 0.24 M and the solution Si/Al ratios ranged from 0.125 to 8. The solutions were transferred to polypropylene bottles and stored in an oven set at a constant temperature of 70 deg. C for 1, 4, 7, 14 and 30 days. At appropriate reaction times, samples were extracted from the oven and then centrifuged to separate the solids from the liquid. The supernatant was filtered using 0.2 μm filter and the solids were washed several times before drying in a freeze dryer. The solids were characterized by XRD and SEM-EDX to

  15. Using solute and heat tracers for aquifer characterization in a strongly heterogeneous alluvial aquifer

    Science.gov (United States)

    Sarris, Theo S.; Close, Murray; Abraham, Phillip

    2018-03-01

    A test using Rhodamine WT and heat as tracers, conducted over a 78 day period in a strongly heterogeneous alluvial aquifer, was used to evaluate the utility of the combined observation dataset for aquifer characterization. A highly parameterized model was inverted, with concentration and temperature time-series as calibration targets. Groundwater heads recorded during the experiment were boundary dependent and were ignored during the inversion process. The inverted model produced a high resolution depiction of the hydraulic conductivity and porosity fields. Statistical properties of these fields are in very good agreement with estimates from previous studies at the site. Spatially distributed sensitivity analysis suggests that both solute and heat transport were most sensitive to the hydraulic conductivity and porosity fields and less sensitive to dispersivity and thermal distribution factor, with sensitivity to porosity greatly reducing outside the monitored area. The issues of model over-parameterization and non-uniqueness are addressed through identifiability analysis. Longitudinal dispersivity and thermal distribution factor are highly identifiable, however spatially distributed parameters are only identifiable near the injection point. Temperature related density effects became observable for both heat and solute, as the temperature anomaly increased above 12 degrees centigrade, and affected down gradient propagation. Finally we demonstrate that high frequency and spatially dense temperature data cannot inform a dual porosity model in the absence of frequent solute concentration measurements.

  16. Porous boron doped diamonds as metal-free catalysts for the oxygen reduction reaction in alkaline solution

    Science.gov (United States)

    Suo, Ni; Huang, Hao; Wu, Aimin; Cao, Guozhong; Hou, Xiaoduo; Zhang, Guifeng

    2018-05-01

    Porous boron doped diamonds (BDDs) were obtained on foam nickel substrates with a porosity of 80%, 85%, 90% and 95% respectively by hot filament chemical vapor deposition (HFCVD) technology. Scanning electron microscopy (SEM) reveals that uniform and compact BDDs with a cauliflower-like morphology have covered the overall frame of the foam nickel substrates. Raman spectroscopy shows that the BDDs have a poor crystallinity due to heavily doping boron. X-ray photoelectron spectroscopy (XPS) analysis effectively demonstrates that boron atoms can be successfully incorporated into the crystal lattice of diamonds. Electrochemical measurements indicate that the oxygen reduction potential is unaffected by the specific surface area (SSA), and both the onset potential and the limiting diffusion current density are enhanced with increasing SSA. It is also found that the durability and methanol tolerance of the boron doped diamond catalysts are attenuated as the increasing of SSA. The SSA of the catalyst is directly proportional to the oxygen reduction activity and inversely to the durability and methanol resistance. These results provide a reference to the application of porous boron doped diamonds as potential cathodic catalysts for the oxygen reduction reaction in alkaline solution by adjusting the SSA.

  17. Hydrogen Evolution Reaction Property in Alkaline Solution of Molybdenum Disulfide Modified by Surface Anchor of Nickel–Phosphorus Coating

    Directory of Open Access Journals (Sweden)

    Jun He

    2017-06-01

    Full Text Available Molybdenum disulfide (MoS2 is unfavorable for practical application in the hydrogen evolution reaction (HER process due to its inert basal surface, inferior conductivity, and limited amount of active edge sites. For the purpose of enhancing the HER performance of this catalyst, the HER activity of its basal surface should be increased. Herein, three types of nickel-phosphorus (Ni–P coatings—namely, low phosphorus (LP, medium phosphorus (MP and high phosphorus (HP —were anchored onto the surfaces of MoS2 nanoparticles via an electroless plating process; thus, three Ni–P/MoS2 composites (Ni–LP/MoS2, Ni–MP/MoS2, and Ni–HP/MoS2 were fabricated. Crystal structures, morphologies, chemical components, and HER performances of each in an alkaline solution were characterized. Both Ni–LP/MoS2 and Ni–MP/MoS2 showed a crystal nature, while the amorphous feature for Ni–HP/MoS2 was validated. The three Ni–P/MoS2 composites exhibited a higher HER activity than the pure MoS2. The HER performance of the Ni–MP/MoS2 composite was more outstanding than those of other two composites, which could be attributed to the presence of metastable nickel phosphides, and the excellent conductivity of Ni–MP coating anchored on the basal surface of MoS2.

  18. Ni nanoparticles supported on graphene layers: An excellent 3D electrode for hydrogen evolution reaction in alkaline solution

    Science.gov (United States)

    Wang, Lixin; Li, Yao; Xia, Meirong; Li, Zhiping; Chen, Zhouhao; Ma, Zhipeng; Qin, Xiujuan; Shao, Guangjie

    2017-04-01

    Metal Ni is a plentiful resource that can actively split water toward hydrogen evolution reaction (HER) in alkaline solution, but exploiting high-efficiency Ni-based composite catalysts is still a significant assignment. Therefore, we design a catalytic material with one-step approach to co-electrodeposit Ni nanoparticles and reduced graphene oxide (rGO) sheets on a three-dimensional Ni foam. When the carbon content existed in Ni-rGO composite catalyst is 3.335 at%, the catalyst exhibits excellent activity on HER with a low Tafel slope (b = 77 mV dec-1), a high exchange current density (j0 = 3.408 mA cm-2), small overpotentials of only 36, 129, and 183 mV to drive 10, 60, and 100 mA cm-2 respectively, and high stability under the different current densities. Such remarkable hydrogen evolution performance is attributed to good electrical conductivity, large specific surface area and harmonious synergistic effect between Ni particles and rGO sheets. In addition, density functional theory (DFT) calculations explain that Ni-rGO composite material presents superior interfacial activity in adsorption/desorption of H* compared with pure Ni and rGO sheet.

  19. Microwave assisted synthesis and characterization of Ni/NiO nanoparticles as electrocatalyst for methanol oxidation in alkaline solution

    Science.gov (United States)

    Arunachalam, Prabhakarn; Ghanem, Mohamed A.; Al-Mayouf, Abdullah M.; Al-shalwi, Matar; Hamed Abd-Elkader, Omar

    2017-02-01

    Nickel/Nickel oxide (Ni/NiO) nanoparticles catalyst is prepared by microwave-assisted liquid-phase deposition using ethylene glycol (EG) and water mixture under atmospheric conditions. The physicochemical characterizations of the catalyst carried out by surface area analyzer, x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), electron microscopes measurements suggest the formation of crystalline nanoparticles structure of NiO. The surface area of Ni/NiO prepared using EG/water mixture reaches 70 m2 g-1 which is 2-fold enhsancement in surface area in comparison with NiO prepared in pure EG and an order of magnitude higher than that of bulk nickel prepared in pure water. The methanol electro-oxidation activity of the Ni/NiO nanoparticles obtained in EG/water mixture displayed more than 4-fold increase in oxidation current at 1.7 V versus RHE in comparison with NiO nanoparticles obtained in EG and 20-fold increase compared to bulk nickel catalyst concord with the enhancement of electro-active surface area. The results show the Ni/NiO nanoparticles produced by microwave assisted synthesis has superior activity for methanol oxidation in alkaline solution over the other nickel based catalysts and has potential for mass production.

  20. Fabrication and characterization of silver/titanium dioxide composite nanoparticles in ethylene glycol with alkaline solution through sonochemical process.

    Science.gov (United States)

    Jhuang, Ya-Yi; Cheng, Wen-Tung

    2016-01-01

    This paper aims to study fabrication and characterization of silver/titanium oxide composite nanoparticle through sonochemical process in the presence of ethylene glycol with alkaline solution. By using ultrasonic irradiation of a mixture of silver nitrate, the dispersed TiO2 nanoparticle in ethylene glycol associated with aqueous solution of sodium oxide yields Ag/TiO2 composite nanoparticle with shell/core-type geometry. The powder X-ray diffraction (XRD) of the Ag/TiO2 composites showed additional diffraction peaks corresponding to the face-centered cubic (fcc) structure of silver crystallization phase, apart from the signals from the cores of TiO2. Transmission electron microscopy (TEM) images of Ag/TiO2 composites, which average particle size is roughly 80 nm, reveal that the titanium oxide coated by Ag nanoparticle with a grain size of about 2-5 nm. Additionally, the formation of silver nanoparticles on TiO2 was monitored by ultraviolet visible light spectrophotometer (UV-Vis). As measured the optical absorption spectra of as-synthesized Ag nanoparticle varying with time, the mechanism of surface formatting silver shell on the cores of TiO2 could be explored by autocatalytic reaction; the conversion of Ag particle from silver ion is 98% for the reaction time of 1000 s; and the activity energy of synthesizing Ag nanoparticles on TiO2 is 40 kJ/mol at temperature ranging from 5 to 25°C. Hopefully, this preliminary investigation could be used for mass production of composite nanoparticles assisted by ultrasonic chemistry in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Monte Carlo solutions of Schroedinger's equation for H2+ ion in strong magnetic fields

    International Nuclear Information System (INIS)

    Ozaki, Jiro; Tomishima, Yasuo

    1980-01-01

    The analytical expressions suitable for the Monte Carlo calculation to obtain the solution of Schroedinger's equation of hydrogen molecular ion in a strong magnetic field are derived. The wave functions, the energy values and the equilibrium internuclear distances of 1σsub(g) state of H 2 + are obtained numerically through the Monte Carlo simulation and compared with other results based on the variational method. The agreement between them is fairly good over a wide range of magnetic field. The calculation of the energy values of 1πsub(g) state of H 2 + for various internuclear distances taking a constant magnetic field as a parameter, shows that the antibonding 1πsub(g) state in the absence of the external magnetic field changes to a bonding state with an increasing magnetic field. The lowest energy values and the equilibrium internuclear distances of 1πsub(g) state are also calculated for various magnetic field. (author)

  2. KARAKTERISASI FISIKOKIMIA NANOKALSIUM HASIL EKSTRAKSI TULANG IKAN NILA MENGGUNAKAN LARUTAN BASA DAN ASAM [Physicochemical Characterization of Nano Calcium from Tilapia Bone Extracted by Alkaline and Acid Solution

    Directory of Open Access Journals (Sweden)

    Vanessa Lekahena*

    2014-06-01

    Full Text Available The utilization of tilapia (Oreochromis niloticus bones as a source of natural calcium was done by alkaline (NaOH and acid (HCl extraction. The extraction process aims to soften the bones are milled using disc mill into nano sized calcium powder or nanocalcium. The objective of this research was to study the physicochemical properties of nanocalcium obtained from alkaline and acid extraction of tilapia bones. The results of physicochemical analysis properties of nanocalcium sample showed that nanocalcium extracted by alkaline solution had better properties than that of the untreated sample and nanocalcium extracted by acid solution. The results was indicated by the higher yield, brighter colors, smaller particle size, and calcium content (20.67% and phosphorus (10.09% with a ratio of Ca/P = 2.0. The Fourier Transform Infrared (FTIR spectra profile indicated the presence of phosphate group (PO43- at the bands of 469, 563, 603, 961 and 1035 cm-1, and the presence of apatite carbonate group (CO32- was indicated by intense bands at 873, 1416, 1456 and 1563 cm-1. The morphology of the sampel surface of the alkaline extracted sample was smoother, denser, and the grain size formed were relatively larger. The formed crystalline phases were HAp (hydroxyapatite, carbonate apatite type A [Ca10(PO46CO3] and B [Ca10(PO43(CO33(OH2] with crystalline degree of 78.4%.

  3. Strong Circularly Polarized Luminescence from Highly Emissive Terbium Complexes in Aqueous Solution

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, Amanda; Lunkley, Jamie; Muller, Gilles; Raymond, Kenneth

    2010-03-15

    Two luminescent terbium(III) complexes have been prepared from chiral ligands containing 2-hydroxyisophthalamide (IAM) antenna chromophores and their non-polarized and circularly-polarized luminescence properties have been studied. These tetradentate ligands, which form 2:1 ligand/Tb{sup III} complexes, utilize diaminocyclohexane (cyLI) and diphenylethylenediamine (dpenLI) backbones, which we reasoned would impart conformational rigidity and result in Tb{sup III} complexes that display both large luminescence quantum yield ({phi}) values and strong circularly polarized luminescence (CPL) activities. Both Tb{sup III} complexes are highly emissive, with {phi} values of 0.32 (dpenLI-Tb) and 0.60 (cyLI-Tb). Luminescence lifetime measurements in H{sub 2}O and D{sub 2}O indicate that while cyLI-Tb exists as a single species in solution, dpenLI-Tb exists as two species: a monohydrate complex with one H{sub 2}O molecule directly bound to the Tb{sup III} ion and a complex with no water molecules in the inner coordination sphere. Both cyLI-Tb and dpenLI-Tb display increased CPL activity compared to previously reported Tb{sup III} complexes made with chiral IAM ligands. The CPL measurements also provide additional confirmation of the presence of a single emissive species in solution in the case of cyLI-Tb, and multiple emissive species in the case of dpenLI-Tb.

  4. Removal of tartrazine from aqueous solutions by strongly basic polystyrene anion exchange resins.

    Science.gov (United States)

    Wawrzkiewicz, Monika; Hubicki, Zbigniew

    2009-05-30

    The removal of tartrazine from aqueous solutions onto the strongly basic polystyrene anion exchangers of type 1 (Amberlite IRA-900) and type 2 (Amberlite IRA-910) was investigated. The experimental data obtained at 100, 200, 300 and 500 mg/dm(3) initial concentrations at 20 degrees C were applied to the pseudo-first order, pseudo-second order and Weber-Morris kinetic models. The calculated sorption capacities (q(e,cal)) and the rate constant of the first order adsorption (k(1)) were determined. The pseudo-second order kinetic constants (k(2)) and capacities were calculated from the plots of t/q(t) vs. t, 1/q(t) vs. 1/t, 1/t vs. 1/q(t) and q(t)/t vs. q(t) for type 1, type 2, type 3 and type 4 of the pseudo-second order expression, respectively. The influence of phase contact time, solution pH and temperature on tartrazine removal was also discussed. The FTIR spectra of pure anion exchangers and those loaded with tartrazine were recorded, too.

  5. Hydrogen generation by aluminum corrosion in aqueous alkaline solutions of inorganic promoters: The AlHidrox process

    International Nuclear Information System (INIS)

    Macanas, Jorge; Soler, Lluis; Candela, Angelica Maria; Munoz, Maria; Casado, Juan

    2011-01-01

    The research of alternative processes to obtain clean fuels has become a main issue because of the concerns related to the current energy system, both from economical and environmental points of view. Hydrogen storage and production methods are being investigated for stationary and portable applications. Up to now, a significant part of H 2 production on demand was thought to be fulfilled by using chemical hydrides, but recent studies have proved the limitations of this approach. Conversely, H 2 production based in the corrosion of light metals in water solutions is an interesting alternative. Among all of them, Al is probably the most adequate metal for energetic purposes due to its high electron density and oxidation potential. But concerning H 2 production from Al corrosion in water, a major issue remains unsolved: metal passivation due to the formation of Al(OH) 3 inhibits H 2 evolution. In this work we show the last results obtained for the generation of H 2 from water using Al powder using diverse alkaline solutions. It is confirmed that corrosion is not affected solely by the solution pH but also by the nature of the ionic species found in the aqueous medium. Moreover, we describe the AlHidrox process, which minimizes Al passivation under mild conditions by the addition of different inorganic salts as corrosion promoters, allowing 100% yields and flow rates up to 2.9 L/min per gram of Al. The feasibility of the process has been regarded in terms of stability (by conducting several successive runs) and self-initiation without an external heating. -- Highlights: → The AlHidrox process minimizes Al passivation by the addition of inorganic salts. → Al corrosion to produce H 2 greatly depends on the nature of the dissolved species. → The maximum flow achieved was 2.9 dm 3 H 2 min -1 .per gram of Al using Fe 2 (SO 4 ) 3 . → We found conditions to start up H 2 generation without external energy input.

  6. Effect of the nature of alkali and alkaline-earth oxides on the structure and crystallization of an alumino-borosilicate glass developed to immobilize highly concentrated nuclear waste solutions

    International Nuclear Information System (INIS)

    Quintas, A.; Caurant, D.; Majerus, O.; Charpentier, T.; Dussossoy, J.L.

    2008-01-01

    A complex rare-earth rich alumino-borosilicate glass has been proved to be a good candidate for the immobilization of new high level radioactive wastes. A simplified seven-oxides composition of this glass was selected for this study. In this system, sodium and calcium cations were supposed in other works to simulate respectively all the other alkali (R + = Li + , Rb + , Cs + ) and alkaline-earth (R 2+ = Sr 2+ , Ba 2+ ) cations present in the complex glass composition. Moreover, neodymium or lanthanum are used here to simulate all the rare-earths and actinides occurring in waste solutions. In order to study the impact of the nature of R + and R 2+ cations on both glass structure and melt crystallization tendency during cooling, two glass series were prepared by replacing either Na + or Ca 2+ cations in the simplified glass by respectively (Li + , K + , Rb + , Cs + ) or (Mg 2+ , Sr 2+ , Ba 2+ ) cations. From these substitutions, it was established that alkali ions are preferentially involved in the charge compensation of (AlO 4 ) - entities in the glass network comparatively to alkaline-earth ions. The glass compositions containing calcium give way to the crystallization of an apatite silicate phase bearing calcium and rare-earth ions. The melt crystallization tendency during cooling strongly varies with the nature of the alkaline-earth. (authors)

  7. Numerical path integral solution to strong Coulomb correlation in one dimensional Hooke's atom

    Science.gov (United States)

    Ruokosenmäki, Ilkka; Gholizade, Hossein; Kylänpää, Ilkka; Rantala, Tapio T.

    2017-01-01

    We present a new approach based on real time domain Feynman path integrals (RTPI) for electronic structure calculations and quantum dynamics, which includes correlations between particles exactly but within the numerical accuracy. We demonstrate that incoherent propagation by keeping the wave function real is a novel method for finding and simulation of the ground state, similar to Diffusion Monte Carlo (DMC) method, but introducing new useful tools lacking in DMC. We use 1D Hooke's atom, a two-electron system with very strong correlation, as our test case, which we solve with incoherent RTPI (iRTPI) and compare against DMC. This system provides an excellent test case due to exact solutions for some confinements and because in 1D the Coulomb singularity is stronger than in two or three dimensional space. The use of Monte Carlo grid is shown to be efficient for which we determine useful numerical parameters. Furthermore, we discuss another novel approach achieved by combining the strengths of iRTPI and DMC. We also show usefulness of the perturbation theory for analytical approximates in case of strong confinements.

  8. Enzymatically mediated bioprecipitation of heavy metals from industrial wastes and single ion solutions by mammalian alkaline phosphatase.

    Science.gov (United States)

    Chaudhuri, Gouri; Shah, Gaurav A; Dey, Pritam; S, Ganesh; Venu-Babu, P; Thilagaraj, W Richard

    2013-01-01

    The study was aimed at investigating the potential use of calf intestinal alkaline phosphatase (CIAP) enzyme in the removal of heavy metals (Cd(2+), Ni(2+), Co(2+) and Cr(3+/6+)) from single ion solutions as well as tannery and electroplating effluents. CIAP mediated bioremediation (white biotechnology) is a novel technique that is eco-friendly and cost effective unlike the conventional chemical technologies. Typical reactions containing the enzyme (CIAP) and p-nitrophenyl phosphate (pNPP) as substrate in Tris-HCl buffer (pH 8 and 11) and either single ion metal solutions (250 ppm and 1000 ppm) or effluents from tannery or electroplating industry were incubated at 37°C for 30 min, 60 min and 120 min. The inorganic phosphate (P(i)) generated due to catalytic breakdown of pNPP complexes free metal ions as metal-phosphate and the amount of metal precipitated was derived by estimating the reduction in the free metal ion present in the supernatant of reactions employing atomic absorption spectrophotometer (AAS). Better precipitation of metal was obtained at pH 11 than at pH 8 and between the two concentrations of different metals tested, an initial metal concentration of 250 ppm in the reaction gave more precipitation than with 1000 ppm. Experimental data showed that at pH 11, the percentage of removal of metal ions (for an initial concentration of 250 ppm) was in the following order: Cd(2+) (80.99%) > Ni(2+) (64.78%) > Cr(3+) > (46.15%) > Co(2+) (36.47%) > Cr(6+) (32.33%). The overall removal of Cr(3+) and Cr(6+) from tannery effluent was 32.77% and 37.39% respectively in 120 min at pH 11. Likewise, the overall removal of Cd(2+), Co(2+) and Ni(2+) from electroplating effluent was 50.42%, 13.93% and 38.64% respectively in 120 min at pH 11. The study demonstrates that bioprecipitation by CIAP may be a viable and environmental friendly method for clean-up of heavy metals from tannery and electroplating effluents.

  9. Strong isotope effects on melting dynamics and ice crystallisation processes in cryo vitrification solutions.

    Directory of Open Access Journals (Sweden)

    Oleg Kirichek

    Full Text Available The nucleation and growth of crystalline ice during cooling, and further crystallization processes during re-warming are considered to be key processes determining the success of low temperature storage of biological objects, as used in medical, agricultural and nature conservation applications. To avoid these problems a method, termed vitrification, is being developed to inhibit ice formation by use of high concentration of cryoprotectants and ultra-rapid cooling, but this is only successful across a limited number of biological objects and in small volume applications. This study explores physical processes of ice crystal formation in a model cryoprotective solution used previously in trials on vitrification of complex biological systems, to improve our understanding of the process and identify limiting biophysical factors. Here we present results of neutron scattering experiments which show that even if ice crystal formation has been suppressed during quench cooling, the water molecules, mobilised during warming, can crystallise as detectable ice. The crystallisation happens right after melting of the glass phase formed during quench cooling, whilst the sample is still transiting deep cryogenic temperatures. We also observe strong water isotope effects on ice crystallisation processes in the cryoprotectant mixture. In the neutron scattering experiment with a fully protiated water component, we observe ready crystallisation occurring just after the glass melting transition. On the contrary with a fully deuteriated water component, the process of crystallisation is either completely or substantially supressed. This behaviour might be explained by nuclear quantum effects in water. The strong isotope effect, observed here, may play an important role in development of new cryopreservation strategies.

  10. On the strong solution of a class of partial differential equations that arise in the pricing of mortgage backed securities

    KAUST Repository

    Parshad, Rana

    2011-01-01

    We consider a reduced form pricing model for mortgage backed securities, formulated as a non-linear partial differential equation. We prove that the model possesses a weak solution. We then show that under additional regularity assumptions on the initial data, we also have a mild solution. This mild solution is shown to be a strong solution via further regularity arguments. We also numerically solve the reduced model via a Fourier spectral method. Lastly, we compare our numerical solution to real market data. We observe interestingly that the reduced model captures a number of recent market trends in this data, that have escaped previous models.

  11. High-order approximate solutions of strongly nonlinear cubic-quintic Duffing oscillator based on the harmonic balance method

    Science.gov (United States)

    Chowdhury, M. S. H.; Hosen, Md. Alal; Ahmad, Kartini; Ali, M. Y.; Ismail, A. F.

    In this paper, a new reliable analytical technique has been introduced based on the Harmonic Balance Method (HBM) to determine higher-order approximate solutions of the strongly nonlinear cubic-quintic Duffing oscillator. The application of the HBM leads to very complicated sets of nonlinear algebraic equations. In this technique, the high-order nonlinear algebraic equations are approximated in the form of a power series solution, and this solution produces desired results even for small as well as large amplitudes of oscillation. Moreover, a suitable truncation formula is found in which the solution measures better results than existing results and it saves a lot of calculation. It is highly noteworthy that using the proposed technique, the third-order approximate solutions gives an excellent agreement as compared with the numerical solutions (considered to be exact). The proposed technique is applied to the strongly nonlinear cubic-quintic Duffing oscillator to reveals its novelty, reliability and wider applicability.

  12. Similar influence of stabilized alkaline and neutral sodium hypochlorite solutions on the fracture resistance of root canal-treated bovine teeth.

    Science.gov (United States)

    Souza, Erick Miranda; Calixto, Amanda Martins; Lima, Camila Nara E; Pappen, Fernanda Geraldo; De-Deus, Gustavo

    2014-10-01

    Stabilizing sodium hypochlorite (NaOCl) at an alkaline pH is proposed to increase solution stability and tissue dissolution ability; however, a reduction on the flexural strength of dentin discs has been found to be a side effect. This study sought to determine whether a stabilized alkaline NaOCl reduces the fracture resistance of root canal-treated bovine teeth after root canal preparation compared with a neutral solution counterpart. The 4 anterior incisors were removed from 20 mandibular bovine jaws, and each 1 was randomly assigned to 1 of 4 groups (20 teeth each). Teeth were prepared with a sequence of 6 K-type files. The following experimental groups received a different irrigation regimen: G1: distilled water (negative control), G2: 5% NaOCl at a pH of 7.2, and G3: 5% NaOCl at a pH of 12.8; in the positive control group (G4), teeth remained untreated. The time of contact and volume of solution were carefully standardized. After bone and periodontal ligament simulation, teeth were subjected to a fracture resistance test. A significant difference was observed among the 4 groups tested (analysis of variance, P .05). No differences were observed between positive and negative control groups (Tukey test, P > .05). Stabilized alkaline and neutral NaOCl solutions similarly reduced the fracture resistance of root canal-treated bovine teeth by about 30%. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. On local strong solutions to the three-dimensional nonhomogeneous incompressible magnetohydrodynamic equations with density-dependent viscosity and vacuum

    Science.gov (United States)

    Song, Sisi

    2018-04-01

    This paper concerns the three-dimensional nonhomogeneous incompressible magnetohydrodynamic equations with density-dependent viscosity and vacuum on Ω \\subset R^3. The domain Ω \\subset R^3 is a general connected smooth one, either bounded or unbounded. In particular, the initial density can have compact support when Ω is unbounded. First, we obtain the local existence and uniqueness of strong solution to the three-dimensional nonhomogeneous incompressible magnetohydrodynamic equations without any compatibility condition assumed on the initial data. Then, we also prove the continuous dependence of strong solution on the initial data under an additional compatibility condition.

  14. Distributions of 14 elements on 60 selected absorbers from two simulant solutions (acid-dissolved sludge and alkaline supernate) for Hanford HLW Tank 102-SY

    International Nuclear Information System (INIS)

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1993-10-01

    Sixty commercially available or experimental absorber materials were evaluated for partitioning high-level radioactive waste. These absorbers included cation and anion exchange resins, inorganic exchangers, composite absorbers, and a series of liquid extractants sorbed on porous support-beads. The distributions of 14 elements onto each absorber were measured from simulated solutions that represent acid-dissolved sludge and alkaline supernate solutions from Hanford high-level waste (HLW) Tank 102-SY. The selected elements, which represent fission products (Ce, Cs, Sr, Tc, and Y); actinides (U, Pu, and Am); and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr), were traced by radionuclides and assayed by gamma spectrometry. Distribution coefficients for each of the 1680 element/absorber/solution combinations were measured for dynamic contact periods of 30 min, 2 h, and 6 h to provide sorption kinetics information for the specified elements from these complex media. More than 5000 measured distribution coefficients are tabulated

  15. Distributions of 14 elements on 60 selected absorbers from two simulant solutions (acid-dissolved sludge and alkaline supernate) for Hanford HLW Tank 102-SY

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1993-10-01

    Sixty commercially available or experimental absorber materials were evaluated for partitioning high-level radioactive waste. These absorbers included cation and anion exchange resins, inorganic exchangers, composite absorbers, and a series of liquid extractants sorbed on porous support-beads. The distributions of 14 elements onto each absorber were measured from simulated solutions that represent acid-dissolved sludge and alkaline supernate solutions from Hanford high-level waste (HLW) Tank 102-SY. The selected elements, which represent fission products (Ce, Cs, Sr, Tc, and Y); actinides (U, Pu, and Am); and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr), were traced by radionuclides and assayed by gamma spectrometry. Distribution coefficients for each of the 1680 element/absorber/solution combinations were measured for dynamic contact periods of 30 min, 2 h, and 6 h to provide sorption kinetics information for the specified elements from these complex media. More than 5000 measured distribution coefficients are tabulated.

  16. Fiber degradability of sugar cane bagasse treated by alkaline solutions, through the “in situ” nylon bag technique

    Directory of Open Access Journals (Sweden)

    Sérgio Carlo Franco Morgulis

    1996-09-01

    treated bagasse (A was higher than in B or C treatments; degradability of B was higher than in C at 72h and 96h of incubation time. NDF degradability at 48 hour incubation time showed the following results: A = 74.0%; B = 41.6% and C = 35.7%. In conclusion, alkaline (NaOH and wood ash treated sugar cane bagasse improves ruminal degradability, and NaOH is better than wood ash.

  17. Aluminum anode for aluminum-air battery - Part II: Influence of In addition on the electrochemical characteristics of Al-Zn alloy in alkaline solution

    Science.gov (United States)

    Park, In-Jun; Choi, Seok-Ryul; Kim, Jung-Gu

    2017-07-01

    Effects of Zn and In additions on the aluminum anode for Al-air battery in alkaline solution are examined by the self-corrosion rate, cell voltage, current-voltage characteristics, anodic polarization, discharge performance and AC impedance measurements. The passivation behavior of Zn-added anode during anodic polarization decreases the discharge performance of Al-air battery. The addition of In to Al-Zn anode reduces the formation of Zn passivation film by repeated adsorption and desorption behavior of In ion onto anode surface. The attenuated Zn passive layer by In ion attack leads to the improvement of discharge performance of Al-air battery.

  18. Communication: Strong laser alignment of solvent-solute aggregates in the gas-phase

    Science.gov (United States)

    Trippel, Sebastian; Wiese, Joss; Mullins, Terry; Küpper, Jochen

    2018-03-01

    Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of the electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with ⟨cos2 θ2D⟩ ≥ 0.9.

  19. Effect of the nature of alkali and alkaline-earth oxides on the structure and crystallization of an alumino-borosilicate glass developed to immobilize highly concentrated nuclear waste solutions

    Energy Technology Data Exchange (ETDEWEB)

    Quintas, A.; Caurant, D.; Majerus, O. [Laboratoire de Chimie de la Matiere Condensee de Paris (UMR 7574), Ecole Nationale Superieure de Chimie de Paris - ENSCP, ParisTech, Paris, 75005 (France); Charpentier, T. [CEA Saclay, Laboratoire de Structure et Dynamique par Resonance Magnetique, DSM/DRECAM/SCM - CEA CNRS URA 331, Gif-sur-Yvette, 91191 (France); Dussossoy, J.L. [Laboratoire d' Etude de Base sur les Verres, CEA Valrho, DEN/DTCD/SCDV/LEBV, Bagnols-sur-Ceze, 30207 (France)

    2008-07-01

    A complex rare-earth rich alumino-borosilicate glass has been proved to be a good candidate for the immobilization of new high level radioactive wastes. A simplified seven-oxides composition of this glass was selected for this study. In this system, sodium and calcium cations were supposed in other works to simulate respectively all the other alkali (R{sup +} = Li{sup +}, Rb{sup +}, Cs{sup +}) and alkaline-earth (R{sup 2+} = Sr{sup 2+}, Ba{sup 2+}) cations present in the complex glass composition. Moreover, neodymium or lanthanum are used here to simulate all the rare-earths and actinides occurring in waste solutions. In order to study the impact of the nature of R{sup +} and R{sup 2+} cations on both glass structure and melt crystallization tendency during cooling, two glass series were prepared by replacing either Na{sup +} or Ca{sup 2+} cations in the simplified glass by respectively (Li{sup +}, K{sup +}, Rb{sup +}, Cs{sup +}) or (Mg{sup 2+}, Sr{sup 2+}, Ba{sup 2+}) cations. From these substitutions, it was established that alkali ions are preferentially involved in the charge compensation of (AlO{sub 4}){sup -} entities in the glass network comparatively to alkaline-earth ions. The glass compositions containing calcium give way to the crystallization of an apatite silicate phase bearing calcium and rare-earth ions. The melt crystallization tendency during cooling strongly varies with the nature of the alkaline-earth. (authors)

  20. Blood gas analysis, anion gap, and strong ion difference in horses treated with polyethylene glycol balanced solution (PEG 3350 or enteral and parenteral electrolyte solutions

    Directory of Open Access Journals (Sweden)

    Cláudio Luís Nina Gomes

    2014-06-01

    Full Text Available Large volumes of different electrolytes solutions are commonly used for ingesta hydration in horses with large colon impaction, but little is known about their consequences to blood acid-base balance. To evaluate the effects of PEG 3350 or enteral and parenteral electrolyte solutions on the blood gas analysis, anion gap and strong ion difference, five adult female horses were used in a 5x5 latin square design. The animals were divided in five groups and distributed to each of the following treatments: NaCl (0.9% sodium chloride solution; EES (enteral electrolyte solution, EES+LR (EES plus lactated Ringer's solution; PEG (balanced solution with PEG 3350 and PEG+LR (PEG plus lactated Ringer's solution. Treatments PEG or PEG + LR did not change or promoted minimal changes, while the EES caused a slight decrease in pH, but its association with lactated Ringer's solution induced increase in AG and SID values, as well as caused hypernatremia. In turn, the treatment NaCl generated metabolic acidosis. PEG 3350 did not alter the acid-base balance. Despite it's slight acidifying effect, the enteral electrolyte solution (EES did not cause clinically relevant changes.

  1. Strong solutions for the Navier-Stokes equations on bounded and unbounded domains with a moving boundary

    Directory of Open Access Journals (Sweden)

    Juergen Saal

    2007-02-01

    Full Text Available It is proved under mild regularity assumptions on the data that the Navier-Stokes equations in bounded and unbounded noncylindrical regions admit a unique local-in-time strong solution. The result is based on maximal regularity estimates for the in spatial regions with a moving boundary obtained in [16] and the contraction mapping principle.

  2. Method of cleaning alkaline metal

    International Nuclear Information System (INIS)

    Kawakami, Yukio; Naito, Kesahiro; Iizawa, Katsuyuki; Nakasuji, Takashi

    1981-01-01

    Purpose: To prevent scattering of used sodium and aqueous alkaline solution when cleaning used sodium and metallic sodium adhering to equipment with an aqueous alkaline solution. Method: A sodium treating container is filled with an aqueous alkaline solution, and stainless steel gauze is sunk in the container. Equipment to be cleaned such as equipment with sodium adhering to it are retained under the gauze and are thus cleaned. On the other hand, the surface of the aqueous alkaline solution is covered with a fluid paraffin liquid covering material. Thus, the hydrogen produced by the reaction of the sodium and the aqueous alkaline solution will float up, pass through the liquid covering material and be discharged. The sodium will pass through the gauze and float upwardly while reacting with the aqueous alkaline solution in a partic ulate state to the boundary between the aqueous alkaline solution and up to the covering material, and thus the theratment reaction will continue. Thus, the cover material prevents the sodium and the aqueous alkaline solution from scattering. (Kamimura, M.)

  3. Domains of analyticity for response solutions in strongly dissipative forced systems

    International Nuclear Information System (INIS)

    Corsi, Livia; Feola, Roberto; Gentile, Guido

    2013-01-01

    We study the ordinary differential equation εx ¨ +x . +εg(x)=εf(ωt), where g and f are real-analytic functions, with f quasi-periodic in t with frequency vector ω. If c 0 ∈R is such that g(c 0 ) equals the average of f and g′(c 0 ) ≠ 0, under very mild assumptions on ω there exists a quasi-periodic solution close to c 0 with frequency vector ω. We show that such a solution depends analytically on ε in a domain of the complex plane tangent more than quadratically to the imaginary axis at the origin

  4. Removal and Recovery of Chromium from Solutions Simulating Tannery Wastewater by Strong Acid Cation Exchanger

    OpenAIRE

    Cetin, Gulten; Kocaoba, Sevgi; Akcin, Goksel

    2013-01-01

    The process in this study was conducted on removal of chromium(III) in a solution simulating a typical spent chrome tanning bath by the resin having matrix of styrene-divinylbenzene-based macroporous sulphonate, Amberjet 1200Na. The column experiments were carried out with the bed volumes of the resin as 751 mL and 1016 mL for different installation systems of the laboratory-scale pilot plant. The feeding solutions in the bed volumes of 200 and 190 were used for each installation system. The ...

  5. Purification of alkaline solutions and wastes from actinides and technetium by coprecipitation with some carriers using the method of appearing reagents: Final Report

    International Nuclear Information System (INIS)

    Peretrukhin, V.F.; Silin, V.I.; Kareta, A.V.; Gelis, A.V.; Shilov, V.P.; German, K.E.; Firsova, E.V.; Maslennikov, A.G.; Trushina, V.E.

    1998-09-01

    The coprecipitation of transuranium elements (TRU) and technetium from alkaline solutions and from simulants of Hanford Site tank wastes has been studied in reducing and oxidizing conditions on uranium(IV,VI) hydroxocompounds, tetraalkylammonium perrhenate and perchlorate, and on hydroxides of Fe(III), Co(III), Mn(II), and Cr(III) using the method of appearing reagents (MAR). Coprecipitations in alkaline solution have been shown to give high decontamination factors (DF) at low content of carrier and in the presence of high salt concentrations. Uranium(IV) hydroxide in concentrations higher than 3 x 10 -3 M coprecipitates Pu and Cm in any oxidation state from 0.2 to 4 M NaOH with DFs of 110 to 1000 and Np and Tc with DFs of 51 to 176. Technetium (VII) coprecipitates with (5 to 8) x 10 -4 M tetrabutylammonium (TBA) perrhenate in 0.01 to 0.02 M TBA hydroxide from 0.5 to 1.5 M NaOH to give DFs of 150 to 200. Coprecipitations of Np and Pu with Co(OH) 3 , Fe(OH) 3 , Cr(OH) 3 , and Mn(OH) 2 obtained by the MAR from precursors in the range from pH 10.5 to 0.4 M NaOH give DFs from 80 to 400

  6. Blow-Up of Solutions for a Class of Sixth Order Nonlinear Strongly Damped Wave Equation

    Directory of Open Access Journals (Sweden)

    Huafei Di

    2014-01-01

    Full Text Available We consider the blow-up phenomenon of sixth order nonlinear strongly damped wave equation. By using the concavity method, we prove a finite time blow-up result under assumptions on the nonlinear term and the initial data.

  7. A steady Navier-Stokes model for compressible fluid with partially strong solutions

    Czech Academy of Sciences Publication Activity Database

    Muzereau, O.; Neustupa, Jiří; Penel, P.

    2010-01-01

    Roč. 348, 11-12 (2010), s. 619-624 ISSN 1631-073X R&D Projects: GA ČR GA201/08/0012 Institutional research plan: CEZ:AV0Z10190503 Keywords : Navier-Stokes equations * Compressible fluids * Weak solution Subject RIV: BA - General Mathematics Impact factor: 0.399, year: 2010 http://www.sciencedirect.com/science/article/pii/S1631073X10001160

  8. Robustness of strong solutions to the compressible Navier-Stokes system

    Czech Academy of Sciences Publication Activity Database

    Bella, P.; Feireisl, Eduard; Jin, B.J.; Novotný, A.

    2015-01-01

    Roč. 362, 1-2 (2015), s. 281-303 ISSN 0025-5831 EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : compressible Navier-Stokes system * smooth solution * stability Subject RIV: BA - General Mathematics Impact factor: 1.366, year: 2015 http://link.springer.com/article/10.1007%2Fs00208-014-1119-2

  9. Amino-functionalized alkaline clay with cationic star-shaped polymer as adsorbents for removal of Cr(VI) in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yuanfeng, E-mail: panyf@gxu.edu.cn [Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Cai, Pingxiong [Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Farmahini-Farahani, Madjid [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3 (Canada); Li, Yiduo [Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Hou, Xiaobang [School of Environmental Sci & Eng., North China Electric Power University, Baoding 071003 (China); Xiao, Huining, E-mail: hxiao@unb.ca [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3 (Canada)

    2016-11-01

    Highlights: • Four-arm cationic star-shaped copolymers were prepared via Atom Transfer Radical Polymerization (ATRP) with pentaerythritol. • Alkaline clay (AC) was immobilized with cationic star polymer (CSP). • CSP-immobilized AC was first used for Cr(VI) removal. • The adsorbent has a higher adsorption capacity than those reported elsewhere. - Abstract: Pentaerythritol (PER) was esterified with 2-bromoisobutyryl bromide to synthesize a four-arm initiator 4Br-PER for atom transfer radical polymerization (ATRP). Star-shaped copolymers (P(AM-co-DMAEMA){sub 4}, CSP) were prepared via ATRP using dimethyl aminoethyl methacrylate (DMAEMA) and acrylamide (AM) as comonomers, while Br-PER and CuBr/2,2′-bipyridine (BPY) as the initiator and the catalyst, respectively. The resulting four-arm initiator and star-shaped polymer (CSP) were characterized with FT-IR, {sup 1}H NMR and Ubbelohde viscometry. Alkaline clay (AC) was immobilized with CSPs to yield amino groups, and the cationic star polymer-immobilized alkaline clay (CSP-AC) was applied to remove Cr(VI) from the aqueous solution in batch experiments. Various influencing factors, including pH, contact time and immobilization amount of CSP on adsorption capacity of CSP-AC for Cr(VI) were also investigated. The results demonstrated that Cr(VI) adsorption was highly pH dependent. The optimized pH value was 4.0. The adsorption isotherms of the adsorbent fit the Langmuir model well, with the maximum adsorption capacity of 137.9 mg/g at 30 °C. The material should be a promising adsorbent for Cr(VI) removal, with the advantages of high adsorption capacity.

  10. Characterization of 'strong-fragile' behaviour of glass-forming aqueous solutions by neutron scattering

    CERN Document Server

    Branca, C; Galli, G; Magazù, S; Maisano, G; Migliardo, F

    2002-01-01

    Neutron-scattering measurements have been performed on trehalose/H sub 2 O and sucrose/H sub 2 O mixtures by using the spectrometer MIBEMOL at the Laboratoire Leon Brillouin (LLB, Saclay) as a function of temperature and concentration. In order to characterize the different rigidities of both the disaccharide/H sub 2 O mixtures, we have evaluated the R sub 1 (T sub g) parameter connected to the 'strong-fragile' classification of the systems according to Angell's nomenclature. (orig.)

  11. Solution of the Neutron transport equation in hexagonal geometry using strongly discontinuous nodal schemes

    International Nuclear Information System (INIS)

    Mugica R, C.A.; Valle G, E. del

    2005-01-01

    In 2002, E. del Valle and Ernest H. Mund developed a technique to solve numerically the Neutron transport equations in discrete ordinates and hexagonal geometry using two nodal schemes type finite element weakly discontinuous denominated WD 5,3 and WD 12,8 (of their initials in english Weakly Discontinuous). The technique consists on representing each hexagon in the union of three rhombuses each one of which it is transformed in a square in the one that the methods WD 5,3 and WD 12,8 were applied. In this work they are solved the mentioned equations of transport using the same discretization technique by hexagon but using two nodal schemes type finite element strongly discontinuous denominated SD 3 and SD 8 (of their initials in english Strongly Discontinuous). The application in each case as well as a reference problem for those that results are provided for the effective multiplication factor is described. It is carried out a comparison with the obtained results by del Valle and Mund for different discretization meshes so much angular as spatial. (Author)

  12. Strong solutions to the Stokes equations of a flow around a rotating body in weighted Lq spaces

    Czech Academy of Sciences Publication Activity Database

    Nečasová, Šárka; Schumacher, K.

    2011-01-01

    Roč. 284, č. 13 (2011), s. 1701-1714 ISSN 0025-584X R&D Projects: GA AV ČR IAA100190505; GA AV ČR IAA100190804; GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : strong solution * Stokes problem * weighted spaces Subject RIV: BA - General Mathematics Impact factor: 0.682, year: 2011 http://onlinelibrary.wiley.com/doi/10.1002/ mana .200810166/abstract

  13. Strong solutions to a Navier–Stokes–Lamé system on a domain with a non-flat boundary

    International Nuclear Information System (INIS)

    Kukavica, Igor; Ziane, Mohammed; Tuffaha, Amjad

    2011-01-01

    In this paper, we consider a Navier–Stokes–Lamé system modeling a fluid–structure interaction. For a general domain, we establish local well-posedness for strong solutions in which initial velocity u 0 belongs to H 1 while the initial data (w 0 , w 1 ) for the elasticity equation belongs to (H 3/2+k , H 1/2+k ) for any k in (0, k 0 ) where k 0 is an explicit positive constant

  14. Relative entropies, suitable weak solutions, and weak-strong uniqueness for the compressible Navier–Stokes system

    Czech Academy of Sciences Publication Activity Database

    Feireisl, Eduard; Jin, B.J.; Novotný, A.

    2012-01-01

    Roč. 14, č. 4 (2012), s. 717-730 ISSN 1422-6928 R&D Projects: GA ČR GA201/09/0917 Institutional research plan: CEZ:AV0Z10190503 Keywords : suitable weak solution * weak-strong uniqueness * compressible Navier-Stokes system Subject RIV: BA - General Mathematics Impact factor: 1.415, year: 2012 http://link.springer.com/article/10.1007%2Fs00021-011-0091-9

  15. The electrochemical reduction of PdCl42- and PdCl62- in polyaniline: Influence of Pd deposit morphology on methanol oxidation in alkaline solution

    International Nuclear Information System (INIS)

    Hatchett, David W.; Millick, Nicole M.; Kinyanjui, John M.; Pookpanratana, Sujitra; Baer, Marcus; Hofmann, Timo; Luinetti, Alessio; Heske, Clemens

    2011-01-01

    Graphical abstract: Display Omitted Highlights: → The synthesis of PANI/Pd composites using PdCl 4 2- and PdCl 6 2- is achieved. → Conductivity of PANI/Pd composites is observed in alkaline solution (pH ∼ 14). → Oxidation of methanol at PANI/Pd is influenced to be the Pd surface morphology. → Surface poisoning is minimized for PANI/Pd produced using PdCl 4 2- . → The Pd metal acts as a solid state dopant in PANI. - Abstract: The controlled uptake and electrochemical reduction of metal precursors PdCl 4 2- and PdCl 6 2- in polyaniline (PANI) is demonstrated. The formation of PANI/Pd composites is achieved with a reduction in proton doping and an increase in the oxidation of the polymer with Pd deposits physically blocking the nitrogen groups. High surface area filaments (PdCl 4 2- ) or a rough encapsulation (PdCl 6 2- ) of Pd metal on PANI are obtained. The structural differences highlight the influence of the metal precursor oxidation state on the morphology of the Pd deposits in PANI. Thermal gravimetric analysis provides an estimate of the Pd content for each composite of ∼40%. X-ray Photoelectron Spectroscopy and X-ray-excited Auger Electron Spectroscopy analyses confirm the deposition of Pd metal. The catalytic oxidation of methanol was demonstrated for both PANI/Pd composites in alkaline solutions that prohibit proton doping of the polymer. The data indicates that Pd metal acts as a solid-state dopant that may delocalize the charge on the polymer backbone to maintain conductivity. Methanol oxidation at PANI/Pd composites produced using PdCl 4 2- was enhanced relative to the composite produced using PdCl 6 2- and a planar Pd electrode. Comparison of PANI/Pd composite produced using PdCl 4 2- with other Pd catalysts from the literature indicates surface poisoning is reduced when Pd is coupled with the polymer. The composite is robust and stable in alkaline solution with the charge density decreasing by 5% on the positive scan and 13% on the

  16. Electrodeposition and characterization of Ni-MoO2 composite coatings as cathodes for the hydrogen evolution reaction in alkaline solution

    Directory of Open Access Journals (Sweden)

    Lačnjevac Uroš Č.

    2013-01-01

    Full Text Available Composite Ni-MoO2 coatings were prepared and characterized with respect to their possible application as electrocatalysts for the hydrogen evolution reaction (HER in alkaline solution. The composites were electrodeposited onto Ni meshes from an ammonium chloride Ni solution with suspended MoO2 particles in simulated industrial conditions for production of commercial cathodes. The influence of the concentration of MoO2 particles in the solution and deposition current density on the morphology, chemical and phase composition of obtained coatings was investigated by scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS and X-ray diffraction (XRD. Catalytic activity for the HER of the coatings was examined by polarization measurements in a 32 wt. % NaOH solution at 90°C and compared to the activity of the commercial De Nora’s cathode (DN. It was shown that the most active Ni-MoO2 coating exhibits better polarization characteristics for the HER than the DN cathode. The mechanism of the HER on the specified Ni-MoO2 coating was investigated in 8 mol dm-3 NaOH at 30°C by means of steady-state polarization measurements and an electrochemical impedance spectroscopy (EIS method. Based on the theoretical interpretation of the experimental data, rate constants of the three individual steps of the HER were determined and the source of catalytic activity of the coating was elucidated. [Projekat Ministarstva nauke Republike Srbije, br. 172054

  17. Comparative Study of the Preparation of Reducing Sugars Hydrolyzed from High-Lignin Lignocellulose Pretreated with Ionic Liquid, Alkaline Solution and Their Combination

    Directory of Open Access Journals (Sweden)

    Hanny F. Sangian

    2015-05-01

    Full Text Available The ionicliquid [MMIM][DMP] was synthesized from the reactants methyl imidazole [MIM] and trimethylphosphate [TMP] and verified using 1HNMR and FTIR. Coconut coir dust was pretreated with a 1% alkaline solution.Its crystalline structure increased significantly due to the dissolution of lignin and hemicelluloses under alkaline conditions, exposing the cellulose. After NaOH and IL were employed, the XRD showed that peak (002 decreased significantly and peak (101 almost vanished. This significant decrease in crystallinity was related to the alteration of the substrate from the cellulose I structure to the cellulose II structure. The pretreated substrates were hydrolyzed to convert them to reducing sugars by pure cellulase and xylanase,and the reaction was conducted at 60°C, pH 3, for 12 or 48 hours. The yields of sugar hydrolyzed from untreated and NaOH-pretreated substrates were 0.07 and 0.12 g sugar/g lignocellulose, respectively. Pretreatment with IL or the combination of NaOH+IL resulted in yields of reducing sugars of 0.11 and 0.13 g/g, respectively. These findings showed that IL pretreatment of the high-lignin lignocellulose is a new prospect for the economical manufacture of reducing sugars and bioethanol in the coming years.

  18. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    cyanide- plating bath for copper has been developed using alkaline trisodium citrate and triethanolamine solutions5. The present investigation presents cyclic voltammetric studies on the electrochemical behaviour of alkaline copper complexes, ...

  19. Properties of altered soils by alkaline solution: contribution in the performance evaluation of repositories; Propriedades de solos alterados por solucao alcalina: contribuicao na avaliacao de desempenho de repositorios

    Energy Technology Data Exchange (ETDEWEB)

    Calabria, Jaqueline Alves de Almeida

    2015-07-01

    very low for all evaluated samples (less than 20% after 10 days of equilibrium), being the best performance one, the nitosoil sample whose K{sub d} values varied from 11.78 to 63.05 mL.g{sup -1}. In a subsequent step, the clay soil, was submitted to the alkaline solution interaction, in order to investigate possible alterations on the sorption properties and hydraulic conductivity of this soil. Using the sorption parameters, obtained from data fitted isotherms, the retardation factor, R, was estimated for the samples before and after the interaction. It was demonstrated that the alkaline alteration promotes damages to sorption properties of Cs, once the R became significantly smaller (about 1000 times) after the interaction. The hydraulic conductivity in turn increased slightly (3,91x10{sup -8} cm.s{sup -1} to 5,08 x 10{sup -8} cm.s{sup -1}). It was concluded that these changes were due, mainly, to the dissolution of minerals present in the clay soil (kaolinite and quartz), associated with the incorporation of K and Ca from the alkaline solution, resulting, probably, in the formation of hydrated calcium silicate phases. Additionally, the effects of alkaline solution on the properties of a commercial bentonite were studied. Contrary to the clay soil, it was observed a gain in the sorption characteristics, with K{sub d} (Cs) increasing from 760.05 mL.g{sup -1}to 1311.80 mL.g{sup -1}and Q{sub max} from 36.32 mg.g{sup -1}to 52.13 mg.g{sup -1}, with the corresponding increase in the retardation coefficient, R. The dissolution of the clay minerals from the initial sample and the incorporation of Mg, K e Ca coming from the alkaline solution, generating smectite of different kinds, were considered as the main mineralogical changes responsible for the modifications in sorption parameters. The different behavior between the two evaluated samples, soil and bentonite, confirms that the nature and extension of changes observed, when mineral samples interact with alkaline solution

  20. Correlation between UV-VIS spectra and the structure of Cu(II complexes with hydrogenated dextran in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Nikolić Goran S.

    2005-01-01

    Full Text Available UV-VIS spectrophotometric investigations of Cu(II complexes with hydroge-nated dextran showed that the complexation of Cu(II-ions began at pH > 7. The formation of Cu(II complexes with dextran monomer units was observed at pH 7-12. With further increase in solution pH > 12, the Cu(II-dextran complex decomposed to Cu(OH42~-ions and dextran. With increasing solution pH the absorption maximum of complex solutions increased and shifted to shorter wavelength (hypsochromic shift compared with uncomplexed Cu(II. The UV spectra displayed bathochromic shifts. The changes of UV-VIS spectra with increasing in solution pH confirmed the formation of different kinds of complex species. The correlation between the results of UV-VIS spectrophotometry and the central metal ionligand coordination predicted that the copper binding within the complex depended on the pH and participation H2O molecules. Dextran complexes with Cu(II were formed by the displacement of water molecules from the coordination sphere of copper by OH groups. The analysis indicated that the Cu(II center was coordinated to two glucopyranose units of dextran. The spectrophotometric parameters of the investigated complexes were characteristic of a Cu(II-ion in a square-planar or tetragon ally distorted octahedral coordination.

  1. A novel solution to the Klein-Gordon equation in the presence of a strong rotating electric field

    Science.gov (United States)

    Raicher, E.; Eliezer, S.; Zigler, A.

    2015-11-01

    The Klein-Gordon equation in the presence of a strong electric field, taking the form of the Mathieu equation, is studied. A novel analytical solution is derived for particles whose asymptotic energy is much lower or much higher than the electromagnetic field amplitude. The condition for which the new solution recovers the familiar Volkov wavefunction naturally follows. When not satisfied, significant deviation from the Volkov wavefunction is demonstrated. The new condition is shown to differ by orders of magnitudes from the commonly used one. As this equation describes (neglecting spin effects) the emission processes and the particle motion in Quantum Electrodynamics (QED) cascades, our results suggest that the standard theoretical approach towards this phenomenon should be revised.

  2. A novel solution to the Klein–Gordon equation in the presence of a strong rotating electric field

    Energy Technology Data Exchange (ETDEWEB)

    Raicher, E., E-mail: erez.raicher@mail.huji.ac.il [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Department of Applied Physics, Soreq Nuclear Research Center, Yavne 81800 (Israel); Eliezer, S. [Department of Applied Physics, Soreq Nuclear Research Center, Yavne 81800 (Israel); Nuclear Fusion Institute, Polytechnic University of Madrid, Madrid (Spain); Zigler, A. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2015-11-12

    The Klein–Gordon equation in the presence of a strong electric field, taking the form of the Mathieu equation, is studied. A novel analytical solution is derived for particles whose asymptotic energy is much lower or much higher than the electromagnetic field amplitude. The condition for which the new solution recovers the familiar Volkov wavefunction naturally follows. When not satisfied, significant deviation from the Volkov wavefunction is demonstrated. The new condition is shown to differ by orders of magnitudes from the commonly used one. As this equation describes (neglecting spin effects) the emission processes and the particle motion in Quantum Electrodynamics (QED) cascades, our results suggest that the standard theoretical approach towards this phenomenon should be revised.

  3. A novel solution to the Klein–Gordon equation in the presence of a strong rotating electric field

    Directory of Open Access Journals (Sweden)

    E. Raicher

    2015-11-01

    Full Text Available The Klein–Gordon equation in the presence of a strong electric field, taking the form of the Mathieu equation, is studied. A novel analytical solution is derived for particles whose asymptotic energy is much lower or much higher than the electromagnetic field amplitude. The condition for which the new solution recovers the familiar Volkov wavefunction naturally follows. When not satisfied, significant deviation from the Volkov wavefunction is demonstrated. The new condition is shown to differ by orders of magnitudes from the commonly used one. As this equation describes (neglecting spin effects the emission processes and the particle motion in Quantum Electrodynamics (QED cascades, our results suggest that the standard theoretical approach towards this phenomenon should be revised.

  4. Strong coupling effects during X-pulse CPMG experiments recorded on heteronuclear ABX spin systems: artifacts and a simple solution

    International Nuclear Information System (INIS)

    Vallurupalli, Pramodh; Scott, Lincoln; Williamson, James R.; Kay, Lewis E.

    2007-01-01

    Simulation and experiment have been used to establish that significant artifacts can be generated in X-pulse CPMG relaxation dispersion experiments recorded on heteronuclear ABX spin-systems, such as 13 C i - 13 C j - 1 H, where 13 C i and 13 C j are strongly coupled. A qualitative explanation of the origin of these artifacts is presented along with a simple method to significantly reduce them. An application to the measurement of 1 H CPMG relaxation dispersion profiles in an HIV-2 TAR RNA molecule where all ribose sugars are protonated at the 2' position, deuterated at all other sugar positions and 13 C labeled at all sugar carbons is presented to illustrate the problems that strong 13 C- 13 C coupling introduces and a simple solution is proposed

  5. Global well-posedness and decay estimates of strong solutions to a two-phase model with magnetic field

    Science.gov (United States)

    Wen, Huanyao; Zhu, Limei

    2018-02-01

    In this paper, we consider the Cauchy problem for a two-phase model with magnetic field in three dimensions. The global existence and uniqueness of strong solution as well as the time decay estimates in H2 (R3) are obtained by introducing a new linearized system with respect to (nγ -n˜γ , n - n ˜ , P - P ˜ , u , H) for constants n ˜ ≥ 0 and P ˜ > 0, and doing some new a priori estimates in Sobolev Spaces to get the uniform upper bound of (n - n ˜ ,nγ -n˜γ) in H2 (R3) norm.

  6. Effect of hydrogen charging on the stability of SAE 10B22 steel surface in alkaline solutions

    International Nuclear Information System (INIS)

    Modiano, S.; Carreno, J.A.; Fugivara, C.S.; Benedetti, A.V.; Mattos, O.R.

    2005-01-01

    The influence of hydrogen charging into a quenched and tempered boron steel membrane electrode (SAE 10B22) was studied using borate buffer (pH 8.4) and NaOH solutions (pH 12.7), with or without the addition of 0.01 M EDTA. At the hydrogen input side, hydrogen charging influenced cyclic voltammograms increasing the anodic charge of iron(II) hydroxide formation, and decreasing the donor density of passive films. These results suggest that the hydrogen ingress caused instability of metallic surface, increasing the surface area activity

  7. Comparison of the Electrochemical Behavior of Ti and Nanostructured Ti-Coated AISI 304 Stainless Steel in Strongly Acidic Solutions

    Science.gov (United States)

    Attarzadeh, Farid Reza; Elmkhah, Hassan; Fattah-Alhosseini, Arash

    2017-02-01

    In this study, the electrochemical behaviors of pure titanium (Ti) and nanostructured (NS) Ti-coated AISI 304 stainless steel (SS) in strongly acidic solutions of H2SO4 were investigated and compared. A type of physical vapor deposition method, cathodic arc evaporation, was applied to deposit NS Ti on 304 SS. Scanning electron microscope and X-ray diffraction were used to characterize surface coating morphology. Potentiodynamic polarization, electrochemical impedance spectroscopy, and Mott-Schottky (M-S) analysis were used to evaluate the passive behavior of the samples. Electrochemical measurements revealed that the passive behavior of NS Ti coating was better than that of pure Ti in 0.1 and 0.01 M H2SO4 solutions. M-S analysis indicated that the passive films behaved as n-type semiconductors in H2SO4 solutions and the deposition method did not affect the semiconducting type of passive films formed on the coated samples. In addition, this analysis showed that the NS Ti coating had lower donor densities. Finally, all electrochemical tests showed that the passive behavior of the Ti-coated samples was superior, mainly due to the formation of thicker, yet less defective passive films.

  8. Enhancement of radiation-induced base release from nucleosides in alkaline solution: essential role of the O.- radical

    International Nuclear Information System (INIS)

    Scholes, M.L.; Schuchmann, M.N.; Sonntag, C. von

    1992-01-01

    The effect of pH on base release in the γ-radiolysis of N 2 O-saturated solutions of a number of nucleosides (including uridine, 3-methyluridine, 2', 3' -O-isopropylidene-uridine, and adenosine) has been investigated. For all these nucleosides, independent of the base or sugar moiety, base release is very low at pH below 10 (G∼(0.3-0.7) x 10 -7 mol J -1 ), but increases drastically to G∼(3-4) x 10 -7 mol J -1 at pH ≥ 13. It is concluded that the increase in base release at high pH is caused by the increasing participation of O .- , which, unlike . OH, attacks the nucleosides preferentially at their sugar moieties, and is not due to an OH - -induced radical transfer from the base to the sugar moiety. (author)

  9. Catalytic Deprotection of Acetals In Strongly Basic Solution Usinga Self-Assembled Supramolecular 'Nanozyme'

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2007-07-26

    Acetals are among the most commonly used protecting groups for aldehydes and ketones in organic synthesis due to their ease of installation and resistance to cleavage in neutral or basic solution.[1] The common methods for hydrolyzing acetals almost always involve the use of either Broensted acid or Lewis acid catalysts.[2] Usually aqueous acids or organic solutions acidified with organic or inorganic acids have been used for reconversion of the acetal functionality to the corresponding carbonyl group; however, recently a number of reports have documented a variety of strategies for acetal cleavage under mild conditions. These include the use of Lewis acids such as bismuth(III)[3] or cerium(IV),[4, 5] functionalized silica gel, such as silica sulfuric acid[6] or silica-supported pyridinium p-toluene sulfonate,[7] or the use of silicon-based reagents such as TESOTf-2,6-Lutidine.[8] Despite these mild reagents, all of the above conditions require either added acid or overall acidic media. Marko and co-workers recently reported the first example of acetal deprotection under mildly basic conditions using catalytic cerium ammonium nitrate at pH 8 in a water-acetonitrile solution.[5] Also recently, Rao and co-workers described a purely aqueous system at neutral pH for the deprotection of acetals using {beta}-cyclodextrin as the catalyst.[9] Herein, we report the hydrolysis of acetals in strongly basic aqueous solution using a self-assembled supramolecular host as the catalyst. During the last decade, we have used metal-ligand interactions for the formation of well-defined supramolecular assemblies with the stoichiometry M{sub 4}L{sub 6}6 (M = Ga{sup III} (1 refers to K{sub 12}[Ga{sub 4}L{sub 6}]), Al{sup III}, In{sup III}, Fe{sup III}, Ti{sup IV}, or Ge{sup IV}, L = N,N{prime}-bis(2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene) (Figure 1).[10] The metal ions occupy the vertices of the tetrahedron and the bisbidentate catecholamide ligands span the edges. The strong

  10. The anodic dissolution of SIMFUEL (UO{sub 2}) in slightly alkaline sodium carbonate/bicarbonate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Keech, P.G.; Goldik, J.S.; Qin, Z. [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London ON, N6A 5B7 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.ca [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London ON, N6A 5B7 (Canada)

    2011-09-30

    The corrosion of nuclear fuel under waste disposal conditions is likely to be influenced by the bicarbonate/carbonate content of the groundwater since it increases the solubility of the U{sup VI} corrosion product, [UO{sub 2}]{sup 2+}. As one of the half reactions involved in the corrosion process, the anodic dissolution of SIMFUEL (UO{sub 2}) has been studied in bicarbonate/carbonate solutions (pH 9.8) using voltammetric and potentiostatic techniques and electrochemical impedance spectroscopy. The reaction proceeds by two consecutive one electron transfer reactions (U{sup IV} {yields} U{sup V} {yields} U{sup VI}). At low potentials ({<=}250 mV (vs. SCE) the rate of the first electron transfer reaction is rate determining irrespective of the total carbonate concentration. At potentials >250 mV (vs. SCE) the formation of a U{sup VI}O{sub 2}CO{sub 3} surface layer begins to inhibit the dissolution rate and the current becomes independent of potential indicating rate control by the chemical dissolution of this layer.

  11. Enhanced dispersion stability and mobility of carboxyl-functionalized carbon nanotubes in aqueous solutions through strong hydrogen bonds

    International Nuclear Information System (INIS)

    Bahk, Yeon Kyoung; He, Xu; Gitsis, Emmanouil; Kuo, Yu-Ying; Kim, Nayoung; Wang, Jing

    2015-01-01

    Dispersion of carbon nanotubes has been heavily studied due to its importance for their technical applications, toxic effects, and environmental impacts. Common electrolytes, such as sodium chloride and potassium chloride, promote agglomeration of nanoparticles in aqueous solutions. On the contrary, we discovered that acetic electrolytes enhanced the dispersion of multi-walled carbon nanotubes (MWCNTs) with carboxyl functional group through the strong hydrogen bond, which was confirmed by UV–Vis spectrometry, dispersion observations and aerosolization-quantification method. When concentrations of acetate electrolytes such as ammonium acetate (CH 3 CO 2 NH 4 ) and sodium acetate (CH 3 CO 2 Na) were lower than 0.03 mol per liter, MWCNT suspensions showed better dispersion and had higher mobility in porous media. The effects by the acetic environment are also applicable to other nanoparticles with the carboxyl functional group, which was demonstrated with polystyrene latex particles as an example

  12. Surface monitoring for pitting evolution into uniform corrosion on Cu-Ni-Zn ternary alloy in alkaline chloride solution: ex-situ LCM and in-situ SECM

    Science.gov (United States)

    Kong, Decheng; Dong, Chaofang; Zheng, Zhaoran; Mao, Feixiong; Xu, Aoni; Ni, Xiaoqing; Man, Cheng; Yao, Jizheng; Xiao, Kui; Li, Xiaogang

    2018-05-01

    The evolution of the corrosion process on Cu-Ni-Zn alloy in alkaline chloride solution was investigated by in-situ scanning electrochemical microscopy, X-ray photoelectron spectroscopy, and ex-situ laser confocal microscopy, and the effects of ambient temperature and polarization time were also discussed. The results demonstrated a higher pitting nucleation rate and lower pit growth rate at low temperature. The ratio of pit depth to mouth diameter decreased with increasing pit volume and temperature, indicating that pits preferentially propagate in the horizontal direction rather than the vertical direction owing to the presence of corrosion products and deposited copper. The surface current was uniform and stabilized at approximately 2.2 nA during the passive stage, whereas the current increased after the pits were formed with the maximum approaching 3 nA. Increasing the temperature led to an increase in porous corrosion products (CuO, Zn(OH)2, and Ni(OH)2) and significantly increased the rate of transition from pitting to uniform corrosion. Dezincification corrosion was detected by energy dispersive spectrometry, and a mechanism for pitting transition into uniform corrosion induced by dezincification at the grain boundaries is proposed.

  13. Mechanochemical synthesis, structure and properties of lead containing alkaline earth metal fluoride solid solutions MxPb1-xF2 (M = Ca, Sr, Ba)

    Science.gov (United States)

    Heise, M.; Scholz, G.; Düvel, A.; Heitjans, P.; Kemnitz, E.

    2018-03-01

    The paper deals with the mechanochemical synthesis of lead containing alkaline earth metal fluoride solid solutions MxPb1-xF2 (M = Ca, Sr, Ba) by high-energy ball milling. Several metal precursors and fluorinating agents were tested for synthesizing M0.5Pb0.5F2. Metal acetates and ammonium fluoride as precursors show the most promising results and were therefore used for the formation of MxPb1-xF2 with different metal cationic ratios. The characterization of the local fluorine coordination and the crystal structure was performed by 19F MAS NMR spectroscopy and X-ray diffraction. Additional calculations of 19F chemical shifts using the superposition model allow a deeper insight into the local structure of the compounds. The fluoride ion conductivity was followed by temperature dependent DC conductivity measurements. Significantly higher conductivities were found in comparison with those of the corresponding binary fluorides. The highest values were observed for samples with high lead content M0.25Pb0.75F2, bearing in mind the much higher conductivity of PbF2 compared to MF2.

  14. Effect of Low-Temperature Environment on Stress Corrosion Cracking Behavior of X80 Pipeline Steel in Simulated Alkaline Soil Solution

    Science.gov (United States)

    Xie, Fei; Wang, Dan; Wu, Ming; Yu, Chengxiang; Sun, Dongxu; Yang, Xu; Xu, Changhao

    2018-01-01

    The stress corrosion cracking (SCC) of X80 pipeline steel in simulated alkaline soil solution under different temperatures was investigated by slow-strain-rate testing, scanning electron microscopy and energy-dispersive spectroscopy. Results showed that the fracture was transgranular and brittle at 273 K to 278 K (0 °C to 5 °C), and the metal surface was dissolved by a large number of chloride ions. Furthermore, hydrogen embrittlement was caused by the hydrogen atom extended to the high-stress region. The fracture process was controlled by hydrogen-induced cracking, and SCC was highly sensitive at this stage. At 288 K to 298 K (15 °C to 25 °C), the fracture morphology was attributed to the mixed mode of ductile and brittle fractures, the fracture process was controlled by the mechanism of hydrogen-induced cracking and anodic dissolution, and the susceptibility to SCC decreased. When the temperature reached 308 K to 318 K (35 °C to 45 °C), the fracture was mainly intergranular and ductile, the fracture process was controlled by anodic dissolution, and SCC sensitivity was the smallest in this temperature range.

  15. Effect of Low-Temperature Environment on Stress Corrosion Cracking Behavior of X80 Pipeline Steel in Simulated Alkaline Soil Solution

    Science.gov (United States)

    Xie, Fei; Wang, Dan; Wu, Ming; Yu, Chengxiang; Sun, Dongxu; Yang, Xu; Xu, Changhao

    2018-04-01

    The stress corrosion cracking (SCC) of X80 pipeline steel in simulated alkaline soil solution under different temperatures was investigated by slow-strain-rate testing, scanning electron microscopy and energy-dispersive spectroscopy. Results showed that the fracture was transgranular and brittle at 273 K to 278 K (0 °C to 5 °C), and the metal surface was dissolved by a large number of chloride ions. Furthermore, hydrogen embrittlement was caused by the hydrogen atom extended to the high-stress region. The fracture process was controlled by hydrogen-induced cracking, and SCC was highly sensitive at this stage. At 288 K to 298 K (15 °C to 25 °C), the fracture morphology was attributed to the mixed mode of ductile and brittle fractures, the fracture process was controlled by the mechanism of hydrogen-induced cracking and anodic dissolution, and the susceptibility to SCC decreased. When the temperature reached 308 K to 318 K (35 °C to 45 °C), the fracture was mainly intergranular and ductile, the fracture process was controlled by anodic dissolution, and SCC sensitivity was the smallest in this temperature range.

  16. Structure and reactivity of thiazolium azo dyes: UV-visible, resonance Raman, NMR, and computational studies of the reaction mechanism in alkaline solution.

    Science.gov (United States)

    Abbott, Laurence C; Batchelor, Stephen N; Moore, John N

    2013-03-07

    UV-visible absorption, resonance Raman, and (1)H NMR spectroscopy, allied with density functional theory (DFT) calculations, have been used to study the structure, bonding, and alkaline hydrolysis mechanism of the cationic thiazloium azo dye, 2-[2-[4-(diethylamino)phenyl]diazenyl]-3-methyl-thiazolium (1a), along with a series of six related dyes with different 4-dialkylamino groups and/or other phenyl ring substituents (2a-c, 3a-c) and the related isothiazolium azo dye, 5-[2-[4-(dimethylamino)phenyl]diazenyl]-2-methyl-isothiazolium (4). These diazahemicyanine dyes are calculated to have a similar low-energy structure that is cis, trans at the (iso)thiazolium-azo group, and for which the calculated Raman spectra provide a good match with the experimental data; the calculations on these structures are used to assign and discuss the transitions giving rise to the experimental spectra, and to consider the bonding and its variation between the dyes. UV-visible, Raman, and NMR spectra recorded from minutes to several weeks after raising the pH of an aqueous solution of 1a to ca. 11.5 show that the dominant initial step in the reaction is loss of diethylamine to produce a quinonimine (ca. hours), with subsequent reactions occurring on longer time scales (ca. days to weeks); kinetic analyses give a rate constant of 2.6 × 10(-2) dm(3) mol(-1) s(-1) for reaction of 1a with OH(-). UV-visible spectra recorded on raising the pH of the other dyes in solution show similar changes that are attributed to the same general reaction mechanism, but with different rate constants for which the dependence on structure is discussed.

  17. Investigation on the coprecipitation of transuranium elements from alkaline solutions by the method of appearing reagents. Study of the effects of waste components on decontamination from Np(IV) and Pu(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Bessonov, A.A.; Budantseva, N.A.; Gelis, A.V.; Nikonov, M.V.; Shilov, V.P. [Russian Academy of Sciences, Moscow (Russian Federation). Institute of Physical Chemistry

    1997-09-01

    The third stage of the study on the homogeneous coprecipitation of neptunium and plutonium from alkaline high-level radioactive waste solutions by the Method of Appearing Reagents has been completed. Alkaline radioactive wastes exist at the U.S. Department of Energy Hanford Site. The recent studies investigated the effects of neptunium chemical reductants, plutonium(IV) concentration, and the presence of bulk tank waste solution components on the decontamination from tetravalent neptunium and plutonium achieved by homogeneous coprecipitation. Data on neptunium reduction to its tetravalent state in alkaline solution of different NaOH concentrations are given. Eleven reductants were tested to find those most suited to remove neptunium, through chemical reduction, from alkaline solution by homogeneous coprecipitation. Hydrazine, VOSO{sub 4}, and Na{sub 2}S{sub 2}O{sub 4} were found to be the most effective reductants. The rates of reduction with these reductants were comparable with the kinetics of carrier formation. Solution decontamination factors of about 400 were attained for 10{sup -6}M neptunium. Coprecipitation of plutonium(IV) with carriers obtained as products of thermal hydrolysis, redox transformations, and catalytic decomposition of [Co(NH{sub 3}){sub 6}]{sup 3+}, [Fe(CN){sub 5}NO]{sup 2-}, Cr(NO{sub 3}){sub 3}, KMnO{sub 4}, and Li{sub 4}UO{sub 2}(O{sub 2}){sub 3} was studied and results are described. Under optimum conditions, a 100-fold decrease of plutonium concentration was possible with each of these reagents.

  18. Global existence of strong solutions to the three- dimensional incompressible Navier-Stokes equations with special boundary conditions

    Science.gov (United States)

    Riley, Douglas A.

    We study the three-dimensional incompressible Navier- Stokes equations in a domain of the form W'×(0,e) . First, we assume W' is a C3 bounded domain and impose no-slip boundary conditions on 6W'×(0,e ) , and periodic conditions on W'×0,e . Physically, this models fluid flow through a pipe with cross-section W' where the inlet and outlet conditions are assumed periodic. Secondly, we assume W'=(0,l4) ×(0,l5) and impose periodic boundary conditions. This problem is of interest mathematically, and has been more widely considered than the pipe flow problem. For both sets of boundary conditions, we show that a strong solution exists for all time with conditions on the initial data and forcing. We start by recalling that if the forcing function and initial condition do not depend on x3, then a global strong solution exists which also does not depend on x3. Here (x1,x2,x3) ∈W≡W'×( 0,e) . With this observation as motivation, and using an additive decomposition introduced by Raugel and Sell, we split the initial data and forcing into a portion independent of x3 and a remainder. In our first result, we impose a smallness condition on the remainder and assume the forcing function is square- integrable in time as a function into L2(W) . With these assumptions, we prove a global existence theorem that does not require a smallness condition on e or on the portion of the initial condition and forcing independent of x3. However, these quantities do affect the allowable size of the remainder. For our second result, we assume the forcing is only bounded in time as a function into L2(W) . In this case, we need a smallness condition on the initial data, the forcing, and e to obtain global existence. The interesting observation is that the allowable sizes for the initial data and forcing grow as e-->0 . Thus, we obtain a `thin-domain' result as originally obtained by Raugel and Sell. In fact, our results allow the portion of the initial data and forcing independent of x3 to

  19. Nd(III)/Cm(III) complexation with gluconate in NaCl and CaCl2 alkaline solutions: solubility and TRLFS studies

    International Nuclear Information System (INIS)

    Rojo, H.; Gaona, X.; Rabung, T.; Altmaier, M.; Garcia-Gutierrez, M.; Missana, T.

    2015-01-01

    Gluconic acid (GLU) is a poly-hydroxo-carboxylic acid expected in repositories for low and intermediate-level radioactive waste as a component of cementitious materials, added into the cement as water reducer and plasticiser. This work aims at assessing the solubility and aqueous speciation of An(III) and Ln(III) in the presence of GLU and dilute NaCl and CaCl 2 solutions, as background electrolytes. Under-saturation solubility studies with Nd(OH) 3 (am) were conducted in inert gas (Ar) gloveboxes at (22±2) C. degrees. Samples were prepared in dilute NaCl (0.1 M) and CaCl 2 (0.1 and 0.25 M) solutions as background electrolytes. Parallel experimental series were prepared with pH c = constant ≅ 12 and 10 -6 M ≤ [GLU] ≤ 10 -2 M, and with [GLU] = constant = 10 -3 M and 9 ≤ pH c ≤ 13. TRLFS measurements were performed with [Cm(III)] ∼ 10 -7 M per sample, and NaCl (0.1 M) and CaCl 2 (0.1 and 0.25 M) as background electrolytes. Three different concentration levels of Ca 2+ were considered in the NaCl systems: 0, 10 -3 M and 10 -2 M. The initial concentration of GLU in all samples (10 -6 M) was increased to 3.10 -3 M by step-wise additions of NaCl-NaGLU or CaCl 2 -CaGLU 2 solutions of appropriate ionic strength. The solubility of Nd(OH) 3 (am) remained unaffected by GLU in 0.1 M NaCl solutions. On the other hand, the solubility of Nd(OH) 3 (am) in 0.1 and 0.25 M CaCl 2 solutions was clearly increased by GLU under hyper-alkaline conditions. It was observed that the species forming are pH-dependent and unequivocally involve the participation of Ca 2+ , with the likely formation of a Nd-GLU complex with stoichiometry 1:2. No further increase of the Nd(III) concentration was observed at [GLU]tot ≥ 10 -3 M, resulting in an upper solubility limit at [Nd] ∼ 10 -6.5 M. This suggests the formation of a new Ca-Nd-GLU solubility limiting solid phase. Consistently with Nd(III) solubility data, TRLFS confirmed the key role of Ca 2+ in the complexation process, with the

  20. Influence of alkaline (PH 8.3-12.0) and saline solutions on chemical, mineralogical and physical properties of two different bentonites - batch experiments at 25 deg. C

    International Nuclear Information System (INIS)

    Heikola, Tiina; Vuorinen, Ulla; Kumpulainen, Sirpa; Kiviranta, Leena; Korkeakoski, Petri

    2012-01-01

    Document available in extended abstract form only. Construction of a spent fuel repository deep in the bedrock will need supporting structures using cement materials. A part of them can be removed before closure but still it is estimated that about 1000 tonnes will remain in the host rock. Degradation of cementitious materials produces leachates of high pH. If such an alkaline plume reaches the bentonite buffer, it may induce mineralogical and chemical changes in bentonite over long term, and further affect the safety functions of the buffer. Laboratory experiments were done with the objective to gain data of possible alterations in mineralogical, chemical and physical properties of bentonites contacted with high-pH saline solutions. Two untreated, high grade, Na- and Ca-bentonites, were used in batch experiments, which were carried out in an anaerobic glove-box at 25±1 deg. C for 554 days. Each bentonite sample (20 g) was leached with approximately 3.8 L of leaching solution, which equals 190 mL/g of bentonite. The bentonites were leached with three types of simulated cement waters (pH 9.7, 11.3 and 12.0) and one saline groundwater simulate (pH 8.3) as a reference. The leaching solutions were 0.3 M, and contained NaCl and CaCl 2 , and trace amounts of SiO 2 , K, Br, Mg and SO 4 . Dissolved oxygen and carbon dioxide were removed from leaching solutions before mixing of bentonite in PC bottles. The samples were placed on a platform shaker in order to allow better contact between bentonite and the leaching solution. The evolution of pH in the samples was followed by measuring the pH-value of each sample in the solution phase approximately twice a week and the solution was renewed when values of two to three consecutive measurements did not change. On average, the leaching solution was renewed once a month. For each renewal of the leaching solution the phases were separated, the reacted solution withdrawn, and the chemical composition analysed. Before analysis the

  1. New Raman method for aqueous solutions: xi-function dispersion evidence for strong F(-)-water H-bonds in aqueous CsF and KF solutions.

    Science.gov (United States)

    Walrafen, George E

    2005-08-15

    The Raman xi-function dispersion method recently elucidated for the strong H-bond breaker, ClO4-, in water [G. E. Walrafen, J. Chem. Phys. 122, 094510 (2005)] is extended to the strongly H-bond forming ion, F-. Measuring the xi function is analogous to measuring DeltaG from the thermodynamic activity of the water, aH2O, as the stoichiometric mol fraction of the water in the solution decreases due to addition of an electrolyte or nonelectrolyte. xi is the derivative of the OH-stretching part of the Gibbs free energy with respect to the water mol fraction; xiomega identical with-RT[ partial differential ln(Iomega/IREF) partial differentialX2](T,P). I is the Raman intensity at omega (omega=Raman shift in cm-1); IREF, that at an arbitrary reference omega; and, X2 is the water mol fraction (X1=CsF or KF mol fraction). ln(Iomega/IREF) was found to be linear in X2 for the complete range of OH-stretching omega's, with correlation coefficients as large as 0.999 96. Linearity of ln(Iomega/IREF) versus X2 is an experimental fact for all omega's throughout the spontaneous Raman OH-stretching contour; this fact cannot be negated by relative contributions of ultrafast/fast, homogeneous/inhomogeneous processes which may underlie this linearity. Linearity in ln(Iomega/IREF) versus 1T, or in ln(Iomega/IREF) versus P, was also observed for the Raman H-bond energy DeltaE and pair volume DeltaV dispersions, respectively. A low-frequency maximum (MAX) and a high-frequency minimum (MIN) were observed in the xi function dispersion curve. Deltaxi=xiMIN-xiMAX values of -7000+/-800-cal/mol H2O for CsF, and the experimentally equal Deltaxi=-6400+/-1000-cal/mol H2O for KF, were obtained. These Deltaxi's are opposite in sign but have nearly the same absolute magnitude as the Deltaxi value for NaClO4 in water; Deltaxi=+8050+/-100-cal/mol H2O. A positive Deltaxi corresponds to a water-water H-bond breaker; a negative Deltaxi to a H-bond former; specifically, a F--water H-bond former, in the

  2. Solubility and hydrolysis of Np(V) in dilute to concentrated alkaline NaCl solutions. Formation of Na-Np(V)-OH solid phases at 22 C

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, Vladimir G. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; Fellhauer, David; Gaona, Xavier; Dardenne, Kathy; Rothe, Joerg; Altmaier, Marcus [Karlsruhe Institute of Technology (Germany). Inst. for Nuclear Waste Disposal; Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; NRC Kurchatov Institute, Moscow (Russian Federation)

    2017-03-01

    The solubility of Np(V) was investigated at T=22±2 C in alkaline NaCl solutions of different ionic strength (0.1-5.0 M). The solid phases controlling the solubility at different -log{sub 10} m{sub H{sup +}}(pH{sub m}) and NaCl concentration were characterized by XRD, quantitative chemical analysis, SEM-EDS and XAFS (both XANES and EXAFS). Aqueous phases in equilibrium with Np(V) solids were investigated for selected samples within 8.9≤pH{sub m}≤10.3 by UV-vis/NIR absorption spectroscopy. In 0.1 M NaCl, the experimental solubility of the initial greenish NpO{sub 2}OH(am) solid phase is in good agreement with previous results obtained in NaClO{sub 4} solutions, and is consistent with model calculations for fresh NpO{sub 2}OH(am) using the thermodynamic data selection in NEA-TDB. Below pH{sub m}∝11.5 and for all NaCl concentrations studied, Np concentration in equilibrium with the solid phase remained constant during the timeframe of this study (∝2 years). This observation is in contrast to the aging of the initial NpO{sub 2}OH(am) into a more crystalline modification with the same stoichiometry, NpO{sub 2}OH(am, aged), as reported in previous studies for concentrated NaClO{sub 4} and NaCl. Instead, the greenish NpO{sub 2}OH(am) transforms into a white solid phase in those systems with [NaCl]≥1.0 M and pH{sub m}≥11.5, and into two different pinkish phases above pH{sub m}∝13.2. The solid phase transformation is accompanied by a drop in Np solubility of 0.5-2 log{sub 10}-units (depending upon NaCl concentration). XANES analyses of green, white and pink phases confirm the predominance of Np(V) in all cases. Quantitative chemical analysis shows the incorporation of Na{sup +} in the original NpO{sub 2}OH(am) material, with Na:Np ≤ 0.3 for the greenish solids and 0.8 ≤ Na:Np ≤ 1.6 for the white and pinkish phases. XRD data confirms the amorphous character of the greenish phase, whereas white and pink solids show well-defined but discrepant XRD patterns

  3. Obtainment of Hg-free Mn/Zn solutions from spent alkaline batteries; Obtencion de soluciones de Mn/Zn libres de Hg provenientes de pilas alcalinas gastadas

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Nicolas, L.; Espinosa-Ramirez, I. [Instituto Politecnico Nacional, UPALM, Mexico, D.F. (Mexico)]. E-mail: lepeni@hotmail.com; Aguilar, M. [Instituto de Fisica, UNAM, Mexico, D.F. (Mexico); Palacios-Beas, E. [Instituto Politecnico Nacional, UPALM, Mexico, D.F. (Mexico)

    2009-09-15

    As in many other countries, the excessive consumption of alkaline batteries in Mexico has generated highly contaminating wastes, with heavy metal contents such as Mn, Zn, Fe, Hg, Cu and Ni, among others. This has caused a large degree of environmental degradation with repercussions for the health of living beings. Because there are no regulations regarding the disposal of spent batteries, they are thrown out with the rest of the domestic wastes or directly into nature, ending up in open-air landfills or containers where they are incinerated, thereby contaminating the planet's environment, soil and springs. The present work studies the obtainment of solutions of Hg-free Mn and Zn (Mn/Zn {>=} 1) from spent alkaline batteries for use in synthesis of (Mn,Zn)Fe{sub 2}O{sub 4} ferrite by a wet method. The effect is analyzed of the dissolution medium (H{sub 2}SO{sub 4}/H{sub 2}O{sub 2}, HCl and HCl/NO{sub 3}) temperature and time on the percentage of dissolution of the metals present in the electrode material, characterized by atomic absorption (AA) spectroscopy and x-ray diffraction (XRD). The results of the investigation indicate that the best dissolution conditions are MD=H{sub 2}SO{sub 4}/H{sub 2}O{sub 2}, T=50 degrees Celsius and t =30 min, where 94.1 and 90.7 % (w/w) of Mn and Zn are obtained, respectively, with Mn/Zn = 1.51. The mercury content was determined to be 3.91%, higher than that stated by the battery specifications, which is recovered by dissolving with HCl/HNO{sub 3} in the residual solid. [Spanish] En Mexico como en muchos otros paises, el consumo excesivo de pilas alcalinas ha generado desechos altamente contaminantes, con contenidos de metales pesados como Mn, Zn, Fe, Hg, Cu y Ni entre otros, que han provocado un gran deterioro en el medio ambiente repercutiendo en la salud de los seres vivos. Dado que no se tiene una regulacion en cuanto a la disposicion de pilas gastadas, estas se desechan con el resto de las residuos domesticos o directamente

  4. Alkaline Material Effects on Roots of Teeth

    Directory of Open Access Journals (Sweden)

    Sowmya Shetty

    2017-12-01

    Full Text Available The aim of this review was to identify and analyse all studies related to the effects of alkaline materials used in dentistry on roots of teeth. The first part of the review focused on mechanical property alterations of root dentine due to sodium hypochlorite (SH used as an irrigant solution based on MeSH (Medical Subject Heading terms from a previous study by Pascon et al in 2009. The second part reviewed literature on calcium hydroxide (CH, mineral trioxide aggregate (MTA and other alkaline materials used as root canal dressings or filling materials. Additional MeSH terms used included “compressive strength”, “elastic modulus” “flexural strength”, “fracture strength” and “fracture resistance”. The language filter was English. Of the initial 205 articles identified, 49 were included in this review, of which 29 were on SH, 21 on CH/MTA, and 1 relating to both. Many in vitro studies indicated a strong link between reduced mechanical properties of roots of teeth or radicular dentine treated with SH, and when sealers or root fillings with CH- or MTA-based materials were placed in contact with roots or radicular dentine. Recent literature indicates that the association between reduced mechanical properties and alkaline sealers and/or root-filling materials is not as straightforward as previously assumed, and requires further investigation using more valid experimental models.

  5. The pH of very dilute solutions of strong acids – a calculation for a medical or biomedical class involving the application of simple numerical skills

    OpenAIRE

    Peter Michael Barling

    2012-01-01

    This paper presents the solution to a calculationof the pH of a very dilute solution of a strong acid orbase, taking into account the effect of the hydroniumor hydroxyl ions generated from the ionisation of thestrong acid or base on the ionisation of water, as asecond very weak acid. To be solved successfully, thiscalculation involves the concepts of conservation ofcharge, pH and the application of the general solutionto a quadratic equation. Such an exercise involves theapplication of skills...

  6. Eichrom's ABEC trademark resins: Alkaline radioactive waste treatment, radiopharmaceutical, and potential hydrometallurgical applications

    International Nuclear Information System (INIS)

    Bond, A.H.; Gula, M.J.; Chang, F.; Rogers, R.D.

    1997-01-01

    Eichrom's ABEC trademark resins selectivity extract certain anions from high ionic strength acidic, neutral, or strongly alkaline media, and solute stripping can be accomplished by eluting with water. ABEC resins are stable to pH extreme and radiolysis and operate in high ionic strength and/or alkaline solutions where anion-exchange is often ineffective. Potential applications of the ABEC materials include heavy metal and ReO 4 - separations in hydrometallurgy and purification of perrhenate iodide, and iodate in radiopharmaceutical production. Separation of 99m TcO 4 - from its 99 MoO 4 2- parent and stripping with water or physiological saline solution have been demonstrated for radiopharmaceutical applications. Removal of 99 TcO 4 - and 129 I - from alkaline tank wastes has also been successfully demonstrated. The authors will discuss the scale-up studies, process-scale testing, and market development of this new extraction material

  7. Solution phase thermodynamics of strong electrolytes based on ionic concentrations, hydration numbers and volumes of dissolved entities

    Czech Academy of Sciences Publication Activity Database

    Heyrovská, Raji

    2013-01-01

    Roč. 24, č. 6 (2013), s. 1895-1901 ISSN 1040-0400 Institutional support: RVO:68081707 Keywords : Solution thermodynamics * Aqueous electrolytes * Partial electrolytic dissociation Subject RIV: BO - Biophysics Impact factor: 1.900, year: 2013

  8. Equilibrium mononuclear-trinuclear complex in acetonitrile solutions of copper (2) N,N'-ethylene-bis-salicylideneiminate and alkaline earth metal perchlorates

    International Nuclear Information System (INIS)

    Zheltvaj, I.I.; Siritsov, A.I.; Egorova, A.L.; Kamalov, G.L.

    1985-01-01

    Trinuclear adducts of copper (2) NN'-ethylene-bis salicylidenimi=n ate (CuES) with alkaline earth metal perchlorates are dissolved in acetonitrile with the preservation of polynuclear structure, which is confirmed by the data of vibrational and electron spectroscopy. Reversible dissociation of polynuclear adduct is detected, its scale depending on alkaline earth metal nature and increasing in the series Mg 2+ reversible M(CuES) 2 are found, the logarithms of which in the above-mentioned series of metals equal: 11.7+-0.1; 10.5+-0.1; 9.3+-0.1; 8.1+-0.1 and correlate linearly with the absorption band frequencies of the corresponding complexes. Possible reasons for the correlation are discussed

  9. Electrochemical transformations of oxygen and the defect structure of solid solutions on the basis of alkaline earth metal ortho-vanadates

    International Nuclear Information System (INIS)

    Khodos, M.Ya.; Belysheva, G.M.; Brajnina, Kh.Z.

    1986-01-01

    Effect of iso- and heterovalent substitution in the structure of alkaline earth metal ortho-vanadates and synthesis conditions, simulating the definite type of their crystal lattice disordering, on the character of potentiodynamic anodic-cathodic curves has been investigated by the method of cyclic voltammetry. Correlation between signals observed and the defect structure of oxide compounds is refined. Oxygen chemisorption is shown to be determined by concentration of nonequilibrium oxygen vacancies, which formation is accompanied by appearance of quasi-free electrons

  10. Zinc electrode in alkaline electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    McBreen, J.

    1995-12-31

    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  11. On thermodynamics of rhenium ion exchange sorption by strong-base anionite from nitrate-sulfate solutions

    International Nuclear Information System (INIS)

    Blokhin, A.A.; Pak, V.I.; Siracheva, M.K.

    1984-01-01

    The apparent thermodynamic parameters of the process of rhenium absorption by strong-base anionites from nitrate-sulfate media in the range of low degrees of filling the sorbents with perrhenate ions are estimated. On the basis of studying the temperature dependence of ion-exchange rhenium sorption it is shown that this process is accompanied by heat release and entropy reduction

  12. Brownian representations of cylindrical local martingales, martingale problem and strong Markov property of weak solutions of SPDEs in Banach spaces

    Czech Academy of Sciences Publication Activity Database

    Ondreját, Martin

    2005-01-01

    Roč. 55, č. 4 (2005), s. 1003-1039 ISSN 0011-4642 R&D Projects: GA ČR(CZ) GA201/01/1197 Institutional research plan: CEZ:AV0Z10190503 Keywords : Brownian representations * martingale problem * strong Markov property Subject RIV: BA - General Mathematics Impact factor: 0.112, year: 2005

  13. Smoothed solutions in the kinetic theory of e+e- vacuum pair creation in strong laser fields. Linear polarization

    Science.gov (United States)

    Smolyansky, S. A.; Prozorkevich, A. V.; Dmitriev, V. V.; Tarakanov, A. V.

    2014-11-01

    In this paper, the dynamical Schwinger effect of vacuum creation of electron-positron pairs driven by an intense laser pulse is studied on the basis of correct quantum kinetic theory. In the general case, the numerical solutions of corresponding system of kinetic equations exhibit complex time dependence which makes the analysis of the physical processes complicated. In particular, the question of secondary effects, such as creation of annihilation photons from the focus spot of the colliding laser beams, remains an important open problem. In our previous work [S. A. Smolyansky, M. Bonitz and A. V. Prozorkevich, Contrib. Plasma Phys.53 (2013) 788], we presented a perturbation theory which is able to capture the dominant time dependence of the produced electron-positron pair distribution during the pulse (quasiparticle excitations). In the present work, we develop appreciably this approximation scheme. We demonstrate effectiveness of the proposed method for solution of such kind nonstationary problems in the simplest models of the laser field. However, this approach opens perspective for search of the relevant approximate solutions in kinetic theory of the e+e- quasiparticle plasma for the more realistic field models (arbitrary polarization, space inhomogeneous, etc).

  14. A Revisit to the Corrosion Inhibition of Aluminum in Aqueous Alkaline Solutions by Water-Soluble Alginates and Pectates as Anionic Polyelectrolyte Inhibitors

    Directory of Open Access Journals (Sweden)

    Refat Hassan

    2013-01-01

    Full Text Available The corrosion behavior of aluminum (Al in alkaline media in presence of some natural polymer inhibitors has been reinvestigated. The inhibition action of the tested inhibitors was found to obey both Langmuir and Freundlich isotherms models. The inhibition efficiency was found to increase with increasing the inhibitors concentration and decrease with increasing the temperature, suggesting physical adsorption mechanism. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated, and a suitable corrosion mechanism consistent with the kinetic results obtained is suggested and discussed.

  15. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D

    1999-01-01

    Highly capacitive (high surface area) electrodes that are electrochemically stable in strong alkaline electrolyte will form the basis for a new generation of electrical and electrochemical energy storage and conversion devices...

  16. Analytical solutions by squeezing to the anisotropic Rabi model in the nonperturbative deep-strong-coupling regime

    Science.gov (United States)

    Zhang, Yu-Yu; Chen, Xiang-You

    2017-12-01

    An unexplored nonperturbative deep strong coupling (npDSC) achieved in superconducting circuits has been studied in the anisotropic Rabi model by the generalized squeezing rotating-wave approximation. Energy levels are evaluated analytically from the reformulated Hamiltonian and agree well with numerical ones in a wide range of coupling strength. Such improvement ascribes to deformation effects in the displaced-squeezed state presented by the squeezed momentum variance, which are omitted in previous displaced states. The atom population dynamics confirms the validity of our approach for the npDSC strength. Our approach offers the possibility to explore interesting phenomena analytically in the npDSC regime in qubit-oscillator experiments.

  17. Graphene-oxide-supported Pt nanoparticles with high activity and stability for hydrazine electro-oxidation in a strong acidic solution

    Science.gov (United States)

    Kim, Ji Dang; Choi, Myong Yong; Choi, Hyun Chul

    2017-10-01

    Graphene-oxide-supported Pt (GO-Pt) nanoparticles were prepared by performing diimide-activated amidation and used in an electrocatalyst for hydrazine electro-oxidation in 0.5 M H2SO4 solution. The physico-chemical properties of the GO-Pt nanoparticles were characterized with various techniques, which revealed that highly dispersed Pt nanoparticles with an average size of 2.6 nm were densely deposited on the amidated GO due to their strong adhesion. Cyclic voltammograms were obtained and demonstrate that the GO-Pt catalyst exhibits significantly improved catalytic activity and long-term stability in hydrazine electro-oxidation in a strong acidic solution when compared to commercial Pt/C and Pt metal electrodes. These enhanced electrochemical properties are attributed to the large electrochemically active surface area that results from the smaller size and excellent dispersion of the Pt nanoparticles on amidated GO.

  18. On the existence of global strong solutions to the equations modeling a motion of a rigid body around a viscous fluid

    Czech Academy of Sciences Publication Activity Database

    Nečasová, Šárka; Wolf, J.

    2016-01-01

    Roč. 36, č. 3 (2016), s. 1539-1562 ISSN 1078-0947 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : incompressible fluid * motion of rigid body * strong solutions Subject RIV: BA - General Mathematics Impact factor: 1.099, year: 2016 http://www.aimsciences.org/journals/displayArticlesnew.jsp?paperID=11589

  19. A unified ion chromatographic system for the determination of acidity and alkalinity.

    Science.gov (United States)

    Hu, W; Hasebe, K; Iles, A; Tanaka, K

    2001-12-01

    A unified ion chromatographic (IC) system was developed for the determination of acidity or alkalinity. Separation column used was a reversed-phase ODS packed column, which had been modified by saturating it with lithium dodecylsulfate. A slightly acidified LiCl (50 mM LiCl and 0.05 mM H2SO4) aqueous solution was used as the eluent. By conditioning the separation column in this way, both H+ and Li+ ions became bound to the stationary phase. Dodecylsulfate groups with Li+ counterions acted as cation-exchange sites for the separation of hydrogen ions (free acidity determination). The remaining dodecylsulfate groups, with H+ counterions acted as a titrant, which reacted with basic species (total alkalinity determination). The acidity or alkalinity of each sample was measured according to the change in conductance from the eluent baseline level. A positive peak was observed from those samples with a free acidity greater than their total alkalinity, due to the separation/elution of free H+ ions. A negative peak was observed from those samples with a free acidity less than their total alkalinity. This was due to an equivalent amount of eluent H+ ions being re-supplied to the stationary phase while the "solid titrant" consumed by the acid-base reaction was regenerated. The retention time for the peak corresponding to the acidity or alkalinity was governed by the retention time for H+ ions in this IC system. Samples with a free acidity greater than 2.25 microM (tested by determination of H+ ions in pure water in equilibrium with atmospheric CO2) could be analyzed by this method. A very similar detection level was obtained for alkalinity (tested by analyzing standard aqueous NaHCO3 solutions). Aqueous solutions of some strong-acid/strong-base inorganic salts were found to be slightly alkaline. This was measured as a percentage, relative to an NaHCO3 solution at the same concentration. Solutions of NaClO4, Na2SO4, NaI, NaNO3, and NaCl, gave comparative alkalinity values of 8

  20. Bentonite swelling pressure in strong NaCl solutions. Correlation of model calculations to experimentally determined data

    Energy Technology Data Exchange (ETDEWEB)

    Karnland, O. [Clay Technology, Lund (Sweden)

    1998-01-01

    A number of quite different quantitative models concerning swelling pressure in bentonite clay have been proposed. This report discusses a number of models which possibly can be used also for saline conditions. A discrepancy between calculated and measured values was noticed for all models at brine conditions. In general the models predicted a too low swelling pressure compared to what was experimentally found. An osmotic component in the clay/water system is proposed in order to improve the previous conservative use of the thermodynamic model. Calculations of this osmotic component is proposed to be made by use of the clay cation exchange capacity and Donnan equilibrium. Calculations made by this approach showed considerably better correlation to literature laboratory data, compared to calculations made by the previous conservative use of the thermodynamic model. A few verifying laboratory tests were made and are briefly described in the report. The improved model predicts a substantial bentonite swelling pressure also in a saturated sodium chloride solution if the density of the system is sufficiently high. This means in practice that the buffer in a KBS-3 repository will give rise to an acceptable swelling pressure, but that the positive effects of mixing bentonite into a backfill material will be lost if the system is exposed to brines. (orig.). 14 refs.

  1. Bentonite swelling pressure in strong NaCl solutions. Correlation between model calculations and experimentally determined data

    Energy Technology Data Exchange (ETDEWEB)

    Karnland, O. [Clay Technology, Lund (Sweden)

    1997-12-01

    A number of quite different quantitative models concerning swelling pressure in bentonite clay have been proposed by different researchers over the years. The present report examines some of the models which possibly may be used also for saline conditions. A discrepancy between calculated and measured values was noticed for all models at brine conditions. In general the models predicted a too low swelling pressure compared to what was experimentally found. An osmotic component in the clay/water system is proposed in order to improve the previous conservative use of the thermodynamic model. Calculations of this osmotic component is proposed to be made by use of the clay cation exchange capacity and Donnan equilibrium. Calculations made by this approach showed considerably better correlation to literature laboratory data, compared to calculations made by the previous conservative use of the thermodynamic model. A few verifying laboratory tests were made and are briefly described in the report. The improved thermodynamic model predicts substantial bentonite swelling pressures also in saturated sodium chloride solution if the density of the system is high enough. In practice, the model predicts a substantial swelling pressure for the buffer in a KBS-3 repository if the system is exposed to brines, but the positive effects of mixing bentonite into a backfill material will be lost, since the available compaction technique does not give a sufficiently high bentonite density 37 refs, 15 figs

  2. Bentonite swelling pressure in strong NaCl solutions. Correlation between model calculations and experimentally determined data

    International Nuclear Information System (INIS)

    Karnland, O.

    1997-12-01

    A number of quite different quantitative models concerning swelling pressure in bentonite clay have been proposed by different researchers over the years. The present report examines some of the models which possibly may be used also for saline conditions. A discrepancy between calculated and measured values was noticed for all models at brine conditions. In general the models predicted a too low swelling pressure compared to what was experimentally found. An osmotic component in the clay/water system is proposed in order to improve the previous conservative use of the thermodynamic model. Calculations of this osmotic component is proposed to be made by use of the clay cation exchange capacity and Donnan equilibrium. Calculations made by this approach showed considerably better correlation to literature laboratory data, compared to calculations made by the previous conservative use of the thermodynamic model. A few verifying laboratory tests were made and are briefly described in the report. The improved thermodynamic model predicts substantial bentonite swelling pressures also in saturated sodium chloride solution if the density of the system is high enough. In practice, the model predicts a substantial swelling pressure for the buffer in a KBS-3 repository if the system is exposed to brines, but the positive effects of mixing bentonite into a backfill material will be lost, since the available compaction technique does not give a sufficiently high bentonite density

  3. Fluorinated antimony(v) derivatives: strong Lewis acidic properties and application to the complexation of formaldehyde in aqueous solutions.

    Science.gov (United States)

    Tofan, Daniel; Gabbaï, François P

    2016-11-01

    As part of our ongoing studies of water tolerant Lewis acids, we have synthesized and investigated the properties of Sb(C 6 F 5 ) 3 (O 2 C 6 Cl 4 ), a fluorinated stiborane whose Lewis acidity approaches that of B(C 6 F 5 ) 3 . While chloroform solutions of this Lewis acid can be kept open to air or exposed to water for extended periods of time, this new Lewis acid reacts with P t Bu 3 and paraformaldehyde to form the corresponding formaldehyde adduct t Bu 3 P-CH 2 -O-Sb(C 6 F 5 ) 3 (O 2 C 6 Cl 4 ). To test if this reactivity can also be observed with systems that combine the phosphine and the stiborane within the same molecule, we have also prepared o -C 6 H 4 (PPh 2 )(SbAr 2 (O 2 C 6 Cl 4 )) (Ar = Ph, C 6 F 5 ). These yellow compounds, which possess an intramolecular P→Sb interaction, are remarkably inert to water but do, nonetheless, react with and accomodate formaldehyde into the P/Sb pocket. In the case of the fluorinated derivative o -C 6 H 4 (PPh 2 )(Sb(C 6 F 5 ) 2 (O 2 C 6 Cl 4 )), formaldehyde complexation, which occurs in water/dichloromethane biphasic mixtures, is accompanied by a colourimetric turn-off response thus highlighting the potential that this chemistry holds in the domain of molecular sensing.

  4. Bentonite swelling pressure in strong NaCl solutions. Correlation of model calculations to experimentally determined data

    International Nuclear Information System (INIS)

    Karnland, O.

    1998-01-01

    A number of quite different quantitative models concerning swelling pressure in bentonite clay have been proposed. This report discusses a number of models which possibly can be used also for saline conditions. A discrepancy between calculated and measured values was noticed for all models at brine conditions. In general the models predicted a too low swelling pressure compared to what was experimentally found. An osmotic component in the clay/water system is proposed in order to improve the previous conservative use of the thermodynamic model. Calculations of this osmotic component is proposed to be made by use of the clay cation exchange capacity and Donnan equilibrium. Calculations made by this approach showed considerably better correlation to literature laboratory data, compared to calculations made by the previous conservative use of the thermodynamic model. A few verifying laboratory tests were made and are briefly described in the report. The improved model predicts a substantial bentonite swelling pressure also in a saturated sodium chloride solution if the density of the system is sufficiently high. This means in practice that the buffer in a KBS-3 repository will give rise to an acceptable swelling pressure, but that the positive effects of mixing bentonite into a backfill material will be lost if the system is exposed to brines. (orig.)

  5. Despolimerização do poli (tereftalato de etileno - PET: efeitos de tensoativos e excesso de solução alcalina Depolymerization of waste polyethylene terephthalate - PET: effects of surfactants and excess of alkaline solutions

    Directory of Open Access Journals (Sweden)

    Luiz Di Souza

    2008-01-01

    Full Text Available A despolimerização do poli (tereftalato de etileno - PET pós-consumo, em solução aquosa 7,5 mol.L-1 de hidróxido de sódio foi testado a 100 °C e a 1 atm, com objetivo de obter o ácido tereftálico. O efeito de tensoativos e da concentração da solução sobre o rendimento da despolimerização foi estudado quantitativamente via gravimetria e analises térmica. Excesso de solução alcalina aumenta a velocidade de reação dobrando o rendimento em reações com partículas grosseiras. Os tensoativos DDS e Tween são eficientes na catálise das reações equimolares com partículas grosseiras, mas não afetam as reações com solução alcalina em excesso.The depolymerization of waste polyethylene terephthalate (PET in aqueous solutions 7.5 M of sodium hydroxide was tested at 100 °C and 1 atm, in order to obtain the terephthalic acid monomers (TPA. The effect from surfactants and concentration of sodium hydroxide (NaOH on the reaction extent of depolymerization was studied quantitatively by gravimetric and thermal measurements. Excess of alkaline solution catalyze the reaction and doubled the reaction rate with larger particle size PET. The surfactants DDS and Tween are efficient in catalyzing larger particle size PET under equimolar conditions, but do not affect the reactions under excess of alkaline solution.

  6. Kinetic study of the α-tocopherol-regeneration reaction of ubiquinol-10 in methanol and acetonitrile solutions: notable effect of the alkali and alkaline earth metal salts on the reaction rates.

    Science.gov (United States)

    Mukai, Kazuo; Oi, Masanori; Ouchi, Aya; Nagaoka, Shin-ichi

    2012-03-01

    A kinetic study of regeneration reaction of α-tocopherol (α-TocH) by ubiquinol-10 has been performed in the presence of four kinds of alkali and alkaline earth metal salts (LiClO(4), NaClO(4), NaI, and Mg(ClO(4))(2)) in methanol and acetonitrile solutions, using double-mixing stopped-flow spectrophotometry. The second-order rate constants (k(r)'s) for the reaction of α-tocopheroxyl (α-Toc•) radical with ubiquinol-10 increased and decreased notably with increasing concentrations of metal salts in methanol and acetonitrile, respectively. The k(r) values increased in the order of no metal salt NaClO(4) ~ NaI > LiClO(4) > Mg(ClO(4))(2) at the same concentration of metal salts. The metal salts having a smaller ionic radius of cation and a larger charge of cation gave a larger k(r) value in methanol, and a smaller k(r) value in acetonitrile. The effect of anion was almost negligible in both the solvents. Notable effects of metal cations on the UV-vis absorption spectrum of α-Toc• radical were observed in aprotic acetonitrile solution, suggesting complex formation between α-Toc• and metal cations. On the other hand, effects of metal cations were negligible in protic methanol, suggesting that the complex formation between α-Toc• and metal cations is hindered by the hydrogen bond between α-Toc• and methanol molecules. The difference between the reaction mechanisms in methanol and acetonitrile solutions was discussed on the basis of the results obtained. High concentrations of alkali and alkaline earth metal salts coexist with α-TocH and ubiquinol-10 in plasma, blood, and many tissues, suggesting the contribution of the metal salts to the above regeneration reaction in biological systems.

  7. Kinetic study of the aroxyl radical-scavenging reaction of alpha-tocopherol in methanol solution: notable effect of the alkali and alkaline earth metal salts on the reaction rates.

    Science.gov (United States)

    Ouchi, Aya; Nagaoka, Shin-ichi; Abe, Kouichi; Mukai, Kazuo

    2009-10-08

    A kinetic study of the aroxyl (ArO*) radical-scavenging reaction of alpha-tocopherol (alpha-TocH) has been performed in the presence of six kinds of alkali and alkaline earth metal salts (LiI, LiClO(4), NaI, NaClO(4), KI, and Mg(ClO(4))(2)) in methanol solution, using stopped-flow spectrophotometry. The decay rate of the ArO* for the reaction of alpha-TocH with ArO* increased linearly with increasing concentration of metal salts. The second-order rate constants (k(s)) for the reaction of alpha-TocH with ArO* increased in the order of no metal salt concentration of metal salts. For example, the k(s) values in methanol solution including 4.00 x 10(-1) M of LiI and Mg(ClO(4))(2) were 3.04 and 1.30 times larger than that in the absence of metal salts, respectively. The alkali and alkaline earth metal salts having smaller ionic radius of cation and anion and larger charge of cation gave larger rate constants (k(s)). Effects of metal cations on the UV-vis absorption spectra of the alpha-Toc* (and ArO*) radical were negligible in methanol solution, suggesting that the complex formation between the alpha-Toc* (and ArO*) radical molecule and metal cations is hindered by the hydrogen bond between radical and methanol molecules. The results indicate that the hydrogen transfer reaction of alpha-TocH proceeds via an electron transfer intermediate from alpha-TocH to ArO* radicals followed by proton transfer. Both the coordinations of metal cations to the one-electron reduced anions of ArO* (ArO: (-)) and of counteranions to the one-electron oxidized cations of alpha-TocH (alpha-TocH(+)*) may stabilize the intermediate, resulting in the acceleration of electron transfer. On the other hand, the effect of metal salts on the rate of bimolecular self-reaction (2k(d)) of the alpha-Toc* radical was not observed. The result suggests that the hydrogen transfer reaction between two alpha-Toc* radical molecules proceeds via a one-step hydrogen atom transfer mechanism rather than via an

  8. An analytic solution of the non-linear equation ∇2λ(r=f(λ and its application to the ion-atmosphere theory of strong electrolytes

    Directory of Open Access Journals (Sweden)

    S. N. Bagchi

    1981-01-01

    directly into the distribution functions, had been proved to be mathematically consistent. It also yielded reliable physical results for both thermodynamic and transport properties of electrolytic solutions. Further, it has already been proved by the author from theoretical considerations (cf. Bagchi [4]as well as from a posteriori verification (see refs. [1] [2] that the concept of ion-atmosphere and the use of PB equation retain their validities generally. Now during the past 30 years, for convenice of calculations, various simplified versions of the original Dutta-Bagchi distribution function (Dutta & Bagchi [5]had been used successfully in modified DH theory of solutions of strong electrolytes. The primary object of this extensive study, (carried out by the author during 1968-73, was to decide a posteriori by using the exact analytic solution of the relevant PB equation about the most suitable, yet theoretically consistent, form of the distribution function. A critical analysis of these results eventually led to the formulation of a new approach to the statistical mechanics of classical systems, (see Bagchi [2], In view of the uncertainties inherent in the nature of the system to be discussed below, it is believed that this voluminous work, (containing 35 tables and 120 graphs, in spite of its legitimate simplifying assumptions, would be of great assistance to those who are interested in studying the properties of ionic solutions from the standpoint of a physically and mathematically consistent theory.

  9. SrNb(0.1)Co(0.7)Fe(0.2)O(3-δ) perovskite as a next-generation electrocatalyst for oxygen evolution in alkaline solution.

    Science.gov (United States)

    Zhu, Yinlong; Zhou, Wei; Chen, Zhi-Gang; Chen, Yubo; Su, Chao; Tadé, Moses O; Shao, Zongping

    2015-03-23

    The perovskite SrNb0.1 Co0.7 Fe0.2 O3-δ (SNCF) is a promising OER electrocatalyst for the oxygen evolution reaction (OER), with remarkable activity and stability in alkaline solutions. This catalyst exhibits a higher intrinsic OER activity, a smaller Tafel slope and better stability than the state-of-the-art precious-metal IrO2 catalyst and the well-known BSCF perovskite. The mass activity and stability are further improved by ball milling. Several factors including the optimized eg orbital filling, good ionic and charge transfer abilities, as well as high OH(-) adsorption and O2 desorption capabilities possibly contribute to the excellent OER activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Effects of Interfacial Reaction on the Radial Displacement of Oil by Alkaline Solutions Effets des réactions interfaciales sur le déplacement radial de l'huile par les solutions alcalines

    Directory of Open Access Journals (Sweden)

    Nasr-El-Din H. A.

    2006-11-01

    Full Text Available Caustic flooding is frequently used to recover acidic oils in secondary and tertiary recovery modes. This study examines the secondary recovery of an acidic oil by alkaline solutions in a water-wet porous medium using a radial geometry. A model porous medium consisting of sintered glass beads sandwiched between two glass plates was employed to visualize the displacement process. The medium was originally saturated with the oil phase, namely paraffin oil (non-reacting system or paraffin oil doped with 1 wt% linoleic acid (reacting system. The effects of the injection flow rate and the NaOH concentration in the aqueous phase on the displacement pattern were studied experimentally. The volumetric oil recovery at the breakthrough condition was also measured. Dynamic interfacial tension (IFT measurements for the reacting system were measured in a spinning drop tensiometer. A drastic drop in the IFT occurred as a result of the chemical reaction at the interface between the linoleic acid in the oil phase and the NaOH in the aqueous phase. It was also found that the IFT behavior with respect to time was a function of NaOH concentration with a maximum interfacial activity (minimum IFT occurring at 0. 1 w% NaOH. Displacement runs showed a significant change in the displacement patterns during secondary recovery for the reacting system compared with those for the non-reacting one. A significant drop in the breakthrough recovery was obtained for the reacting systems, especially at high injection flow rates. The breakthrough recovery of the reacting system was found to be a function of NaOH concentration in the aqueous phase, with a minimum recovery at NaOH concentration of 0. 1 wt%. On a souvent recours à la submersion par des produits alcalins pour récupérer les acides gras dans les modes secondaire et tertiaire. Dans cette étude, on examine la récupération secondaire d'un acide gras par des solutions alcalines dans un milieu poreux imprégné d

  11. The Effects of Cassia Siamea Lam. Root Extract on the Corrosion and Kinetics of Corrosion Process of Copper in Alkaline Solutions

    OpenAIRE

    Onen, A. I; Nwufo, B. T.; Ebenso, E. E.

    2011-01-01

    The effect of Cassia siamea lam. (CSL) root extract as a corrosion inhibitor of copper in 0.50 M NaOH solutions was investigated using absorbance difference technique at 30 °C and 40 °C. CSL root extract inhibited the corrosion of copper in 0.50 M NaOH solutions and the inhibition efficiency (% IE) increased to a maximum of 78.3±2.3% with increasing concentration of the extract but decreased with increasing temperature. The adsorption of CSL root extract on copper surface followed the Langmui...

  12. Global solutions of restricted open-shell Hartree-Fock theory from semidefinite programming with applications to strongly correlated quantum systems.

    Science.gov (United States)

    Veeraraghavan, Srikant; Mazziotti, David A

    2014-03-28

    We present a density matrix approach for computing global solutions of restricted open-shell Hartree-Fock theory, based on semidefinite programming (SDP), that gives upper and lower bounds on the Hartree-Fock energy of quantum systems. While wave function approaches to Hartree-Fock theory yield an upper bound to the Hartree-Fock energy, we derive a semidefinite relaxation of Hartree-Fock theory that yields a rigorous lower bound on the Hartree-Fock energy. We also develop an upper-bound algorithm in which Hartree-Fock theory is cast as a SDP with a nonconvex constraint on the rank of the matrix variable. Equality of the upper- and lower-bound energies guarantees that the computed solution is the globally optimal solution of Hartree-Fock theory. The work extends a previously presented method for closed-shell systems [S. Veeraraghavan and D. A. Mazziotti, Phys. Rev. A 89, 010502-R (2014)]. For strongly correlated systems the SDP approach provides an alternative to the locally optimized Hartree-Fock energies and densities with a certificate of global optimality. Applications are made to the potential energy curves of C2, CN, Cr2, and NO2.

  13. The Effects of Cassia Siamea Lam. Root Extract on the Corrosion and Kinetics of Corrosion Process of Copper in Alkaline Solutions

    Directory of Open Access Journals (Sweden)

    A. I Onen

    2011-01-01

    Full Text Available The effect of Cassia siamea lam. (CSL root extract as a corrosion inhibitor of copper in 0.50 M NaOH solutions was investigated using absorbance difference technique at 30 °C and 40 °C. CSL root extract inhibited the corrosion of copper in 0.50 M NaOH solutions and the inhibition efficiency (% IE increased to a maximum of 78.3±2.3% with increasing concentration of the extract but decreased with increasing temperature. The adsorption of CSL root extract on copper surface followed the Langmuir adsorption model with the average heat of adsorption, Qads and free energy of adsorption, ΔGads of -8.98 kJmol-1 and -8.70 kJmol-1 respectively. A kinetic treatment of the data revealed a first order kinetics with respect to copper in the presence and absence of the extract.

  14. The effects of acid and alkaline solutions on cut marks and on the structure of bone: An experimental study on porcine ribs.

    Science.gov (United States)

    Amadasi, Alberto; Camici, Arianna; Sironi, Luca; Profumo, Antonella; Merli, Davide; Mazzarelli, Debora; Porta, Davide; Duday, Henri; Cattaneo, Cristina

    2015-11-01

    Among taphonomical modifications during decomposition processes, little is known about the action of high or low pH to human tissues and bones. Moreover, acid or basic solutions are seldom used to ease decomposition and wrecking of the body. In this study a total of 60 samples of porcine bones on which two cut marks were produced before the beginning of the experiment, were put in six different solutions with different pH (1, 3, 5, 9, 12, 14) and analyzed every five days over a period of 70 days. Surveys were carried out macroscopically, with stereomicroscopy and with light microscopy on thin sections. Only the specimens exposed to extremely acid (12) pH showed evident modifications of the bone's structure, as witnessed by the analyses with stereomicroscopy as well. Many samples showed a detachment of the periosteum; cut marks became soon unrecognizable with pH 14 but still detectable in all the other samples. The information gained from the present study can be of great help in detecting the exposure of human tissues to high or low environmental pH and in understanding the effects that these solutions can exert on human bones. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Evolution of the corrosion process of AA 2024-T3 in an alkaline NaCl solution with sodium dodecylbenzenesulfonate and lanthanum chloride inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Biner; Wang, Yishan; Zuo, Yu, E-mail: zuoy@mail.buct.edu.cn

    2015-12-01

    Highlights: • Inhibition effect of LaCl{sub 3} and SDBS for AA 2024 in NaCl solution (pH 10) was studied. • At the beginning the active polarization behavior of the alloy changed to passivation. • The passive behavior gradually disappeared with time and pitting happened at S-phases. • The compounded inhibitors showed good inhibition but cannot totally inhibit pitting. • The adsorption of SDBS played the key role for inhibition to the corrosion process. - Abstract: The evolution of the corrosion process of AA 2024-T3 in 0.58 g L{sup −1} NaCl solution (pH 10) with sodium dodecylbenzenesulfonate (SDBS) and lanthanum chloride inhibitors was studied with electrochemical and surface analysis methods. With the addition of the compounded LaCl{sub 3} and SDBS inhibitors, in the early stage the polarization behavior of AA 2024-T3 changed from active corrosion to passivation, and both the general corrosion and pitting corrosion were inhibited. However, with the immersion time extended, the passive behavior gradually disappeared and pitting happened at the Cu-rich phases. After 24 h immersion, the compounded inhibitors still showed good inhibition for general corrosion, but the polarization curve again presented the characteristic similar to active polarization. The compounded inhibitors also inhibited the pitting corrosion to some extent. The acting mechanism of the inhibitors SDBS and La{sub 3}Cl on the corrosion process of AA 2024-T3 in the test solution was discussed.

  16. A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium

    International Nuclear Information System (INIS)

    Martínez, Javier A.; Valenzuela B, José; Cao Milán, R.; Herrera, José; Farías, Mario H.; Hernández, Mayra P.

    2014-01-01

    Highlights: • New phases of sulfur on gold: hexamer and (√(2)×√(2)) were observed by STM. • Hexamers and (√(2)×√(2)) structures coexist with well-known octomers. • Formation of sulfur multilayer by K 2 DTC 2 pz hydrolysis under alkaline condition. • Top octomer layer have dynamic behavior while (√(2)×√(2)) and hexamer were static. • A model is presented to explain sulfur multilayer formation on Au(100). - Abstract: Piperazine-dithiocarbamate of potassium (K 2 DTC 2 pz) was used as a new precursor for the spontaneous deposition of sulfur on the Au(100) surface in alkaline solution. Two new sulfur phases were studied by scanning tunneling microscopy (STM). These phases were formed by six sulfur atoms (S 6 phase, hexamer) and by four sulfur atoms (S 4 phase, tetramer with (√(2)×√(2)) structure), and they were observed in coexistence with the well-known quasi-square patterns formed by eight sulfur atoms (S 8 phase, octomer). A model was proposed where sulfur multilayers were formed by a (√(2)×√(2)) phase adsorbed directly on the gold surface while one of the other structures: hexamers or octomers were deposited on top. Sulfur layers were formed on gold terraces, vacancies and islands produced by lifting reconstructed surface. Sequential high-resolution STM images allowed the direct observation of the dynamic of the octomers, while the (√(2)×√(2)) structure remained static. Images also showed the reversible association/dissociation of the octomer

  17. A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, Javier A. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Valenzuela B, José [Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM) , km 107 Carretera Tijuana-Ensenada, Ensenada, BC 22860 (Mexico); Cao Milán, R. [Facultad de Química, Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Herrera, José [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Farías, Mario H. [Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM) , km 107 Carretera Tijuana-Ensenada, Ensenada, BC 22860 (Mexico); Hernández, Mayra P., E-mail: mayrap@fisica.uh.cu [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba)

    2014-11-30

    Highlights: • New phases of sulfur on gold: hexamer and (√(2)×√(2)) were observed by STM. • Hexamers and (√(2)×√(2)) structures coexist with well-known octomers. • Formation of sulfur multilayer by K{sub 2}DTC{sub 2}pz hydrolysis under alkaline condition. • Top octomer layer have dynamic behavior while (√(2)×√(2)) and hexamer were static. • A model is presented to explain sulfur multilayer formation on Au(100). - Abstract: Piperazine-dithiocarbamate of potassium (K{sub 2}DTC{sub 2}pz) was used as a new precursor for the spontaneous deposition of sulfur on the Au(100) surface in alkaline solution. Two new sulfur phases were studied by scanning tunneling microscopy (STM). These phases were formed by six sulfur atoms (S{sub 6} phase, hexamer) and by four sulfur atoms (S{sub 4} phase, tetramer with (√(2)×√(2)) structure), and they were observed in coexistence with the well-known quasi-square patterns formed by eight sulfur atoms (S{sub 8} phase, octomer). A model was proposed where sulfur multilayers were formed by a (√(2)×√(2)) phase adsorbed directly on the gold surface while one of the other structures: hexamers or octomers were deposited on top. Sulfur layers were formed on gold terraces, vacancies and islands produced by lifting reconstructed surface. Sequential high-resolution STM images allowed the direct observation of the dynamic of the octomers, while the (√(2)×√(2)) structure remained static. Images also showed the reversible association/dissociation of the octomer.

  18. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    DEFF Research Database (Denmark)

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH

  19. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev [Latham, NY

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  20. Alkaline "Permanent" Paper.

    Science.gov (United States)

    Pacey, Antony

    1991-01-01

    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and…

  1. Lightweight Heat Resistant Geopolymer-based Materials Synthesized from Red Mud and Rice Husk Ash Using Sodium Silicate Solution as Alkaline Activator

    Directory of Open Access Journals (Sweden)

    Hoc Thang Nguyen

    2017-01-01

    Full Text Available Geopolymer is an inorganic polymer composite with potentials to replace Ordinary Portland Cement (OPC-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in our study, the raw materials we used are red mud and rice husk ash, which are are industrial and agricultural wastes that need to be managed to reduce their impact to the environment. The red mud and rice husk ash combined with sodium silicate (water glass solution were mixed to form geopolymer materials. Moreover, the geopolymer specimens were also tested for heat resistance at a temperature of 1000°C for 2 hours. Results suggest high heat resistance with an increase of compressive strength after exposed at high temperature.

  2. Processing Methods of Alkaline Hydrolysate from Rice Husk

    Directory of Open Access Journals (Sweden)

    Olga D. Arefieva

    2017-07-01

    Full Text Available This paper devoted to finding processing methods of alkaline hydrolysate produced from rice husk pre-extraction, and discusses alkaline hydrolysate processing schemed and disengagement of some products: amorphous silica of various quality, alkaline lignin, and water and alkaline extraction polysaccharides. Silica samples were characterized: crude (air-dried, burnt (no preliminary water treatment, washed in distilled water, and washed in distilled water and burnt. Waste water parameters upon the extraction of solids from alkaline hydrolysate dropped a few dozens or thousand times depending on the applied processing method. Color decreased a few thousand times, turbidity was virtually eliminated, chemical oxygen demanded about 20–136 times; polyphenols content might decrease 50% or be virtually eliminated. The most prospective scheme obtained the two following solid products from rice husk alkaline hydrolysate: amorphous silica and alkaline extraction polysaccharide. Chemical oxygen demand of the remaining waste water decreased about 140 times compared to the silica-free solution.

  3. Alkaline battery operational methodology

    Science.gov (United States)

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  4. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

  5. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  6. Characterization and quantification of biochar alkalinity.

    Science.gov (United States)

    Fidel, Rivka B; Laird, David A; Thompson, Michael L; Lawrinenko, Michael

    2017-01-01

    Lack of knowledge regarding the nature of biochar alkalis has hindered understanding of pH-sensitive biochar-soil interactions. Here we investigate the nature of biochar alkalinity and present a cohesive suite of methods for its quantification. Biochars produced from cellulose, corn stover and wood feedstocks had significant low-pK a organic structural (0.03-0.34 meq g -1 ), other organic (0-0.92 meq g -1 ), carbonate (0.02-1.5 meq g -1 ), and other inorganic (0-0.26 meq g -1 ) alkalinities. All four categories of biochar alkalinity contributed to total biochar alkalinity and are therefore relevant to pH-sensitive soil processes. Total biochar alkalinity was strongly correlated with base cation concentration, but biochar alkalinity was not a simple function of elemental composition, soluble ash, fixed carbon, or volatile matter content. More research is needed to characterize soluble biochar alkalis other than carbonates and to establish predictive relationships among biochar production parameters and the composition of biochar alkalis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Toxicity of alkalinity to Hyalella azteca

    Science.gov (United States)

    Lasier, P.J.; Winger, P.V.; Reinert, R.E.

    1997-01-01

    Toxicity testing and chemical analyses of sediment pore water have been suggested for use in sediment quality assessments and sediment toxicity identification evaluations. However, caution should be exercised in interpreting pore-water chemistry and toxicity due to inherent chemical characteristics and confounding relationships. High concentrations of alkalinity, which are typical of sediment pore waters from many regions, have been shown to be toxic to test animals. A series of tests were conducted to assess the significance of elevated alkalinity concentrations to Hyalella azteca, an amphipod commonly used for sediment and pore-water toxicity testing. Toxicity tests with 14-d old and 7-d old animals were conducted in serial dilutions of sodium bicarbonate (NaHCO3) solutions producing alkalinities ranging between 250 to 2000 mg/L as CaCO3. A sodium chloride (NaCl) toxicity test was also conducted to verify that toxicity was due to bicarbonate and not sodium. Alkalinity was toxic at concentrations frequently encountered in sediment pore water. There was also a significant difference in the toxicity of alkalinity between 14-d old and 7-d old animals. The average 96-h LC50 for alkalinity was 1212 mg/L (as CaCO3) for 14-d old animals and 662 mg/L for the younger animals. Sodium was not toxic at levels present in the NaHCO3 toxicity tests. Alkalinity should be routinely measured in pore-water toxicity tests, and interpretation of toxicity should consider alkalinity concentration and test-organism tolerance.

  8. Aluminum corrosion mitigation in alkaline electrolytes containing hybrid inorganic/organic inhibitor system for power sources applications

    Science.gov (United States)

    Gelman, Danny; Lasman, Itay; Elfimchev, Sergey; Starosvetsky, David; Ein-Eli, Yair

    2015-07-01

    The severe corrosion accompanied with hydrogen evolution process is the main obstacle preventing the implementation of Al as an anode in alkaline batteries. It impairs the functionality of alkaline battery, due to a drastic capacity loss and a short shelf life. The possibility to reduce Al corrosion rate in alkaline solution with the use of hybrid organic∖inorganic inhibitor based on poly (ethylene glycol) di-acid (PEG di-acid) and zinc oxide (ZnO) was examined in this work. A correlation between an Al corrosion rates and the concentrations of both PEG di-acid and ZnO in alkaline is shown. Selecting 5000 ppm PEG di-acid and 16 gr/l ZnO provides substantial corrosion protection of Al, reducing the corrosion rate in a strong alkaline solution by more than one order of magnitude. Moreover, utilizing the same formulation results in increase in Al-air battery discharge capacity, from 44.5 (for a battery utilizing only KOH in the electrolyte) to 70 mhA/cm2 (for a battery utilizing ZnO/PEG di-acid hybrid inhibitor in the electrolyte). The morphology and composition of the Al electrode surface (studied by SEM, EDS, and XRD) depend on PEG di-acid and ZnO concentrations.

  9. Strength properties of separators in alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Danko, T. [Viskase Corp., Chicago, IL (United States)

    1996-11-01

    Battery separator non-wovens that were coated with regenerated cellulose via the viscose process were subjected to storage in 40% potassium hydroxide (KOH) over a two month period. Samples were periodically checked for wet MD tensile strength. The test showed that among the non-wovens, the polyamide retained about 93% of its initial tensile strength whereas polyvinyl alcohol and cellulosic non-wovens retained only 55% and 35%, respectively. Adding a viscose coating to the non-wovens improved tensile strength retention by 20--25% for the polyvinyl alcohol and cellulosic materials. The viscose-coated polyamide retained more than 98% of its initial tensile strength.

  10. SOLUTIONING

    Directory of Open Access Journals (Sweden)

    Maria de Hoyos Guajardo, Ph.D. Candidate, M.Sc., B.Eng.

    2004-11-01

    Full Text Available The theory that is presented below aims to conceptualise how a group of undergraduate students tackle non-routine mathematical problems during a problem-solving course. The aim of the course is to allow students to experience mathematics as a creative process and to reflect on their own experience. During the course, students are required to produce a written ‘rubric’ of their work, i.e., to document their thoughts as they occur as well as their emotionsduring the process. These ‘rubrics’ were used as the main source of data.Students’ problem-solving processes can be explained as a three-stage process that has been called ‘solutioning’. This process is presented in the six sections below. The first three refer to a common area of concern that can be called‘generating knowledge’. In this way, generating knowledge also includes issues related to ‘key ideas’ and ‘gaining understanding’. The third and the fourth sections refer to ‘generating’ and ‘validating a solution’, respectively. Finally, once solutions are generated and validated, students usually try to improve them further before presenting them as final results. Thus, the last section deals with‘improving a solution’. Although not all students go through all of the stages, it may be said that ‘solutioning’ considers students’ main concerns as they tackle non-routine mathematical problems.

  11. On performance capabilities of alkaline anolyte in wastewater management

    International Nuclear Information System (INIS)

    Shimkevich, Alexander

    2014-01-01

    A concept for electric converting a saline wastewater into basic solution (pH > 7) with a positive RedOx potential (alkaline anolyte) is considered. Such the medium can be obtained in situ at flowing wastewater via a special electrochemical cell with strongly polarized cathode (generating hydroxide anions) and quasi-equilibrium anode which intensively discharges hydroxide ions to hydroxyl radicals into the wastewater. The radicals will oxidize anions of strong acid and convert them into weak-acid micro precipitates in the flowing basic solution. These renewable nano-sorbents will uninterruptedly co-precipitate radioactive contamination from wastewater and be agglomerated as corrosion by-products in the felt-like anode. The consideration of liquid water as a chemical compound with a wide band gap shows that the anolyte (as a hyper-stoichiometric water, H 2 O 1+|x| ) is a simple and effective tool for varying physical and chemical properties of the aqueous solution due to forced changing its RedOx potential as one needs. This potential as Fermi level in the band gap of liquid water is the most convenient parameter for monitoring and managing the electrochemical potential of the aqueous medium. Its hyper-stoichiometric state is realized when Fermi level is shifted to the top of a valence band. This electro-oxidized state as the alkaline anolyte is characterized by an acceptor level, OH/OH - , partially occupied by electrons. Then, the hydroxyl radical (OH • ) as the strongest oxidizer will oxidize intensively the metal anode and renew its surface for great removal of radio-nuclides from the wastewater due to their large specific area of renewable surface of hydroxide absorber on the felt-like anode. (author)

  12. Alkaline phosphatase: an overview.

    Science.gov (United States)

    Sharma, Ujjawal; Pal, Deeksha; Prasad, Rajendra

    2014-07-01

    Alkaline phosphatase (ALP; E.C.3.I.3.1.) is an ubiquitous membrane-bound glycoprotein that catalyzes the hydrolysis of phosphate monoesters at basic pH values. Alkaline phosphatase is divided into four isozymes depending upon the site of tissue expression that are Intestinal ALP, Placental ALP, Germ cell ALP and tissue nonspecific alkaline phosphatase or liver/bone/kidney (L/B/K) ALP. The intestinal and placental ALP loci are located near the end of long arm of chromosome 2 and L/B/K ALP is located near the end of the short arm of chromosome 1. Although ALPs are present in many mammalian tissues and have been studied for the last several years still little is known about them. The bone isoenzyme may be involved in mammalian bone calcification and the intestinal isoenzyme is thought to play a role in the transport of phosphate into epithelial cells of the intestine. In this review, we tried to provide an overview about the various forms, structure and functions of alkaline phosphatase with special focus on liver/bone/kidney alkaline phosphatase.

  13. Net alkalinity and net acidity 2: Practical considerations

    Science.gov (United States)

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH mine drainage treatment can lead to systems with insufficient Alkalinity to neutralize metal and H+ acidity and is not recommended. The use of net alkalinity = -Hot Acidity titration is recommended for the planning of mine drainage treatment. The use of net alkalinity = (Alkalinitymeasured - Aciditycalculated) is recommended with some cautions

  14. Advanced alkaline water electrolysis

    International Nuclear Information System (INIS)

    Marini, Stefania; Salvi, Paolo; Nelli, Paolo; Pesenti, Rachele; Villa, Marco; Berrettoni, Mario; Zangari, Giovanni; Kiros, Yohannes

    2012-01-01

    A short review on the fundamental and technological issues relevant to water electrolysis in alkaline and proton exchange membrane (PEM) devices is given. Due to price and limited availability of the platinum group metal (PGM) catalysts they currently employ, PEM electrolyzers have scant possibilities of being employed in large-scale hydrogen production. The importance and recent advancements in the development of catalysts without PGMs are poised to benefit more the field of alkaline electrolysis rather than that of PEM devices. This paper presents our original data which demonstrate that an advanced alkaline electrolyzer with performances rivaling those of PEM electrolyzers can be made without PGM and with catalysts of high stability and durability. Studies on the advantages/limitations of electrolyzers with different architectures do show how a judicious application of pressure differentials in a recirculating electrolyte scheme helps reduce mass transport limitations, increasing efficiency and power density.

  15. Extraction of uranium from alkaline medium by organic extractants

    International Nuclear Information System (INIS)

    El - nadi, Y.A.M.

    1996-01-01

    A recent possible route for treatment of small amounts of neutron irradiated uranium from alkaline medium was addressed. This have some advantages related to the isolation of many troublesome fission products which forms insoluble carbonates or hydroxides upon alkaline carbonate dissolution of uranium oxide. In alkaline solution containing sodium carbonate and hydroxide, hexavalent uranium is expected to be dissolved in solution whereby most of the fission products transition elements exemplified by zirconium and niobium as well as trivalent lanthanides and actinides will be precipitated. Therefore, in this medium the solution will contain mainly alkali and alkaline earth metal such as Cs + and Sr 2+ and anionic fission products such as pertechnetates and antimonates, Which can be easily separted from uranium. Therefore, The present thesis is directed to investigate the following; 1 - solubility of uranium oxide in alkaline medium consists of sodium carbonate and sodium hydroxide in presence of oxidizing agent. 2 - Extraction of uranium from the aforementioned alkaline medium by immiscible organic diluent containing different amine extractants. 3 - Extraction behaviour of uranium by the macroporous anion exchanger, amberlite IRA - 410, from alkaline solution

  16. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    Almeida, S.H. de.

    1987-01-01

    A comparative study of niobium electrochemical behaviour in NaOH and KOH solution, with concentrations between 0,5 and 6,1M is presented. The studies were done through electrochemicals assays, consisting in the corrosion potential and anodic and cathodic polarization curves, complemented by loss of mass experiments. The niobium anodic behaviour in alkaline medium is characterized by passivation occurrence, with a stable film formation. The Na oH solution in alkaline medium are more corrosible to niobium than the KOH solution. The loss of mass assays showed that the corrosion velocit is more dependente of hydroxide concentration in KOH medium than the NaOH medium. (C.G.C.) [pt

  17. [Advances of alkaline amylase production and applications].

    Science.gov (United States)

    Yang, Haiquan; Liu, Long; Li, Jianghua; Du, Guocheng; Chen, Jian

    2012-04-01

    Alkaline amylase is one of alkaline enzymes with optimum pH in the alkaline range, and it could keep stability and efficiently hydrolyze starch under alkaline conditions. Alkaline amylase finds wide applications in textile, detergent, pharmaceutical, food and other fields. Alkaline amylases could be produced by alkaliphilic microorganisms. In this work, the advances of alkaline amylase production and applications were reviewed.

  18. Viscosity of Molten Alkaline-Earth Fluorides

    Science.gov (United States)

    Takeda, Osamu; Hoshino, Yosuke; Anbo, Yusuke; Yanagase, Kei-ichi; Aono, Masahiro; Sato, Yuzuru

    2015-04-01

    The viscosities of molten alkaline-earth fluorides were measured using the oscillating crucible method, which is especially suitable for measuring molten salts with low viscosity. The results showed a good Arrhenius linearity over a wide temperature range. The measured viscosities and activation energies increased in the following order: . Judging by the charge density, the viscosity of alkaline-earth fluorides should increase from molten to . However, the results indicate a different tendency, which may be explained by a Coulomb force that is very strong. The low viscosity of can be attributed to a decreased cohesive force, due to a partial loss of the Coulomb force caused by a higher charge density of the material. The viscosities were also compared to those of molten alkali fluorides and alkaline-earth chlorides. The viscosities of molten alkaline-earth fluorides were higher than those of molten alkali fluorides and alkaline-earth chlorides. The viscosity determined in this study was compared to literature values and showed a reasonable value in the relatively low-viscosity region.

  19. Application of alkaline waterflooding to a high acidity crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Sayyouh, M.H. (King Sand Univ., Riyadh (SA). Petroleum Engineering Dept.); Abdel-Waly, A.; Osman, A. (Cairo Univ. (EG). Petroleum Engineering Dept.); Awara, A.Z. (Geisum Oil Company, Cairo (EG))

    The enhanced recovery of a high acidity crude oil (South Geisum crude) by alkaline solutions is studied. Acidity, interfacial tension, and contact angle, were investigated. Displacement tests were carried out to study the effect of alkaline slug concentration, slug size, oil alkali type, temperature and viscosity on recovery. The interfacial tension between crude oil and formation water decreases with increasing alkaline concentration until a minimum, after which it increases again. Contact angle measurements indicated oil-wetting conditions that increase by the addition of alkaline solutions. At the early stages of displacement, oil recovery increases with increasing alkaline concentration until a maximum at 4% by weight NaOH concentration. Also, at such early stages, an excessive increase in alkaline concentration results in lower oil recovery. On the other hand, after the injection of many pore volumes of water, oil recovery is almost the same regardless of the alkaline concentration. Oil recovery increases with increasing alkaline slug size until a maximum at 15% PV. Sodium hydroxide slugs produce more oil recovery than sodium carbonate slugs. Oil recovery increases with increasing temperature (from 25 to 55{sup 0}C) and decreasing oil viscosity.

  20. Effect of Added Surfactants on the Dynamic Interfacial Tension Behaviour of Alkaline/Diluted Heavy Crude Oil System Effet de l’ajout de tensioactifs sur le comportement dynamique de la tension interfaciale du système solution alcaline/brut dilué

    Directory of Open Access Journals (Sweden)

    Trabelsi S.

    2013-02-01

    Full Text Available This study has been undertaken to get a better understanding of the interactions between Enhanced Oil Recovery (EOR surfactants used in chemical flooding and in situ surfactants present in an heavy oil. We report an experimental study of dynamic Interfacial Tension (IFT behaviour of diluted heavy oil/surfactant enhanced-alkaline systems. The dynamic IFT was measured using pendant drop and spinning drop tensiometers. The dynamic IFT between diluted heavy oil and alkaline solution (pH 11 with no added surfactant increased sharply with time, which was attributed to the transfer of the in situ surfactant (produced by saponification of the acids groups present in the crude oil across the oil/water interface. The addition of Sodium Dodecyl Benzene Sulfonate (SDBS above the Critical Micellar Concentration (CMC ~ 0.002%, changed completely the dynamic IFT behaviour of the diluted heavy oil as the IFT strongly decreased and finally reached a plateau, of about 1.5 × 10-3 mN/m at a concentration of only 0.02%. We attributed the efficiency of SDBS to a synergistic effect between the in situ surfactant and the added surfactant that form a mixed interfacial monolayer, which is very efficient in decreasing the IFT to ultra low values and in resisting mass transfer across the oil/water interface. Cette étude a été réalisée pour mieux comprendre les interactions entre les tensioactifs utilisés pour la récupération assistée de pétrole et les tensioactifs in situ présents dans le brut. Nous expérimentons le comportement dynamique des tensions interfaciales (mesurées par les méthodes de goutte pendante et goutte tournante entre le brut lourd dilué et les solutions alcalines avec ajout de tensioactif. La tension interfaciale dynamique entre le brut dilué et une solution alcaline (pH 11 sans ajout de tensioactif croît fortement au cours du temps, cette augmentation est attribuée au transfert des tensioactifs in situ (produits par saponification des

  1. Net alkalinity and net acidity 2: Practical considerations

    Science.gov (United States)

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH calculated based on initial pH and dissolved concentrations of Fe, Mn, and Al minus the initial alkalinity. Acidity calculated from the pH and dissolved metals concentrations, assuming equivalents of 2 per mole of Fe and Mn and 3 per mole of Al, was equivalent to that calculated based on complete aqueous speciation of FeII/FeIII. Despite changes in

  2. Alkaline erosion of CR 39 polymer surfaces

    International Nuclear Information System (INIS)

    Faiman, Laurence

    2009-01-01

    We have investigated the mechanism of erosion of CR 39 polymer in alkaline environments. We observed the kinetics of absorption of water and methanol into both unirradiated and γ-irradiated samples. We use a capillary model to interpret our results. We etched our samples in both KOH solutions, and KOH solutions doped with methanol. Etch rate was desensitizing to γ-irradiation when KOH concentration approached saturation, but KOH solutions doped with methanol were not desensitizing, unlike with nuclear tracks. We account for this difference

  3. Hydrolysis of alkaline pretreated banana peel

    Science.gov (United States)

    Fatmawati, A.; Gunawan, K. Y.; Hadiwijaya, F. A.

    2017-11-01

    Banana peel is one of food wastes that are rich in carbohydrate. This shows its potential as fermentation substrate including bio-ethanol. This paper presented banana peel alkaline pretreatment and enzymatic hydrolysis. The pretreatment was intended to prepare banana peel in order to increase hydrolysis performance. The alkaline pretreatment used 10, 20, and 30% w/v NaOH solution and was done at 60, 70 and 80°C for 1 hour. The hydrolysis reaction was conducted using two commercial cellulose enzymes. The reaction time was varied for 3, 5, and 7 days. The best condition for pretreatment process was one conducted using 30% NaOH solution and at 80°C. This condition resulted in cellulose content of 90.27% and acid insoluble lignin content of 2.88%. Seven-day hydrolysis time had exhibited the highest reducing sugar concentration, which was7.2869 g/L.

  4. Application of Resin in Pulp Technique for Ion Exchange Separation of Uranium from Alkaline Leachate

    International Nuclear Information System (INIS)

    Sreenivas, T.; Rajan, K.C.; Chakravartty, J.K.

    2014-01-01

    Conclusions: • Resin-in-pulp technique was applied for purification and enrichment of uranium values from a finely ground uranium ore leach slurry of alkaline nature using strong base anion exchange resin (size 500 - 675μm). • The chemical composition of the solution phase of the alkaline leach slurry (pH 9.5) was consisting of about 40 g/L of total dissolved solutes (TDS) predominantly with Na 2 CO 3 and NaHCO 3 and minor levels of Na 2 SO 4 . The uranium content was only 730 mg/L and d50 of solids was 34μm. • Amongst the various commercially available resins studied PFA 4740 and 4783 having quaternary ammonium ion on polystyrene crosslink with divibyl benzez (DVB) gave best performance. The maximum loading capacity achieved in the RIP studies was about 60-65 g of U 3 O 8 /L of wet settled resin amounting to 98% of loading. This has necessitated 4 stages of counter-current extraction with overall contact time of 100 minutes at a resin to leach slurry volume ratio of about 1:50. Practically the entire uranium values loaded on the resin were eluted using NaCl. • The RIP process was found quite efficient for uranium bearing alkaline leach slurries.

  5. High-Strength / High Alkaline Resistant Fe-Phosphate Glass Fibers as Concrete Reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Mariano Velez

    2008-03-31

    Calcium-iron-phosphate glasses were developed whose chemical durabilities in alkaline solutions (pH 13) were comparable or superior to those of commercial alkaline-resistant (AR) silica-based glasses. However, the tensile strength of Ca-Fe-phosphate fibers, after being exposed to alkaline environments, including wet Portland cement pastes, is lower than that of current AR silicate fibers. Another series of Ca-Fe-phosphate glasses were developed with excellent chemical durability in strong acidic solutions (H2SO4, HF), indicating potential applications where silica-based fibers degrade very quickly, including E-glass. The new Ca-Fe-phosphate glasses can be melted and processed 300 to 500°C lower than silica-based glasses. This offers the possibility of manufacturing glass fibers with lower energy costs by 40-60% and the potential to reduce manufacturing waste and lower gas emissions. It was found that Ca-Fe-phosphate melts can be continuously pulled into fibers depending on the slope of the viscosity-temperature curve and with viscosity ~100 poise, using multi-hole Pt/Rh bushings.

  6. Effect of exotic long-lived sub-strongly interacting massive particles in big bang nucleosynthesis and a new solution to the Li problem

    Directory of Open Access Journals (Sweden)

    Kawasaki Masahiro

    2012-02-01

    Full Text Available The plateau of 7Li abundance as a function of the iron abundance by spectroscopic observations of metal-poor halo stars (MPHSs indicates its primordial origin. The observed abundance levels are about a factor of three smaller than the primordial 7Li abundance predicted in the standard Big Bang Nucleosynthesis (BBN model. This discrepancy might originate from exotic particle and nuclear processes operating in BBN epoch. Some particle models include heavy (m >> 1 GeV long-lived colored particles which would be confined inside exotic heavy hadrons, i.e., strongly interacting massive particles (SIMPs. We have found reactions which destroy 7Be and 7Li during BBN in the scenario of BBN catalyzed by a long-lived sub-strongly interacting massive particle (sub-SIMP, X. The reactions are non radiative X captures of 7 Be and 7Li which can be operative if the X particle interacts with nuclei strongly enough to drive 7 Be destruction but not strongly enough to form a bound state with 4 He of relative angular momentum L = 1. We suggest that 7Li problem can be solved as a result of a new process beyond the standard model through which the observable signature was left on the primordial Li abundance.

  7. Research on killing Escherichia Coli by reactive oxygen species based on strong ionization discharging plasma

    International Nuclear Information System (INIS)

    Li, Y J; Tian, Y P; Zhang, Z T; Li, R H; Cai, L J; Gao, J Y

    2013-01-01

    Reactive oxygen species solution produced by strong ionization discharging plasma was used to kill Escherichia coli by spraying. Several effect factors such as pH value, solution temperature, spraying time and exposure time were observed in this study, and their effects on killing rate of Escherichia coli were discussed and analysed. Results show that the treating efficiency of ROS solution for Escherichia coli is higher in alkaline solution than that in acid solution. The killing rate of Escherichia coli increases while the spraying time and exposure time are longer and the temperature is lower. The effects of different factors on killing rate of Escherichia coli are as follows: spraying time > pH value > exposure time > solution temperature.

  8. Low-nickel stainless steel passive film in simulated concrete pore solution: A SIMS study

    Science.gov (United States)

    Fajardo, S.; Bastidas, D. M.; Ryan, M. P.; Criado, M.; McPhail, D. S.; Bastidas, J. M.

    2010-08-01

    Low-nickel and AISI 304 austenitic stainless steel (SS) passive films were studied using secondary ion mass spectrometry (SIMS). An alkaline Ca(OH) 2 saturated test solution containing different chloride additions was used at room temperature. The passive film formed consists mainly of an inner chromium-rich oxide layer and an outer iron-rich oxide layer. The chemistry of the passive film depends strongly on the chloride content in the alkaline solution. Under these exposure conditions nickel was detected in the outer part of the oxide, whereas chloride ions were not found in the passive film for either the low-nickel or AISI 304 SS alloys.

  9. Alkaline Activator Impact on the Geopolymer Binders

    Science.gov (United States)

    Błaszczyński, Tomasz Z.; Król, Maciej R.

    2017-10-01

    Concrete structures are constantly moving in the direction of improving the durability. Durability depends on many factors, which are the composition of concrete mix, the usage of additives and admixtures and the place, where material will work and carry the load. The introduction of new geopolymer binders for geopolymer structures adds a new aspect that is type of used activator. This substance with strongly alkaline reaction is divided because of the physical state, the alkaline degree and above all the chemical composition. Taking into account, that at present the geopolymer binders are made essentially from waste materials or by-products from the combustion of coal or iron ore smelting, unambiguous determination of the effect of the activator on the properties of the geopolymer material requires a number of trials, researches and observation. This paper shows the influence of the most alkaline activators on the basic parameters of the durability of geopolymer binders. In this study there were used highly alkaline hydroxides, water glasses and granules, which are waste materials in a variety of processes taking place in chemical plants. As the substrate of geopolymer binders there were used fly ash which came from coal and high calcareous ash from the burning of lignite.

  10. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material.

    Science.gov (United States)

    Subhedar, Preeti B; Gogate, Parag R

    2014-01-01

    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  12. Alkaline fuel cells applications

    Science.gov (United States)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  13. Characterization and Electrocatalytic Properties of Titanium-Based Ru0.3Co0.7−xCex Mixed Oxide Electrodes for Oxygen Evolution in Alkaline Solution

    Directory of Open Access Journals (Sweden)

    Hongjun Wu

    2011-01-01

    Full Text Available Ti-supported RuO2-Co3O4-CeO2 (Ru0.3Co0.7−xCex oxide, 0≤x≤0.7 electrodes were prepared by sol-gel process. The phase structure, surface morphology, and microstructure of the oxide layer were characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM. Electrocatalytic activity and oxygen evolution reaction (OER kinetics on these electrodes in 1.0 mol⋅dm−3 KOH solution were studied by recording open-circuit potential, cyclic voltammetry, and polarisation curves. The results showed that the appropriate content of CeO2 could reduce the grain size and increase active surface area. The electrocatalytic activity shows a strong dependence on the CeO2 content in the film. Catalytic performance of mixed oxide electrodes with 40 mol % CeO2 was the best, with the greatest voltammetric charge, 86.23 mC⋅cm−2, and the smallest apparent activation energy for OER at 0.60 V was 22.76 kJ⋅mol−1.

  14. Stabilitas warna basis gigitiruan resin termoplastik nilon yang direndam dalam larutan pembersih gigitiruan peroksida alkalin Color stability of thermoplastic nylon denture base material immerse in alkaline peroxide denture cleanser

    Directory of Open Access Journals (Sweden)

    Melinda Maria Awing

    2013-06-01

    solution of alkaline peroxide every 8 hours, using 4 speciments for each solutions. Using ANOVA and independent ttest,it showed no significant color changes on thermoplastic nylon resin after immersed in alkaline peroxide solution  based on the time interval. However, there was significant color difference on the thermoplastic nylon resin immersed in alkaline peroxide and control solution at second to seventh interval of 8 hours immersed time with increase of time immersing. It was concluded that thermoplastic nylon resin have good stability although immerse in alkaline peroxide denture cleanser

  15. COUPLING THE ALKALINE-SURFACTANT-POLYMER TECHNOLOGY AND THE GELATION TECHNOLOGY TO MAXIMIZE OIL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qui; Dan Wilson; Phil Dowling

    2004-05-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency those with high permeability contrast ''thief zones''. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than waterflooding in the swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to the naturally fractured reservoirs or those with thief zones because much of the injected solution bypasses the target pore space containing oil. The objective of this work is to investigate whether combining these two technologies could broaden the applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium--polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values of 9.2 to 12.9.

  16. 2nd Generation alkaline electrolysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Yde, L. [Aarhus Univ. Business and Social Science - Centre for Energy Technologies (CET), Aarhus (Denmark); Kjartansdottir, C.K. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Allebrod, F. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark)] [and others

    2013-03-15

    conditions and the degradation mechanism was examined. One of the strong visions for the 2{sup nd} generation electrolyser concept has been to develop a modular system with several standardized components. The following modules have been designed: 1) Electrolyser module; 2) Deoxer Module; 3) Dryer Module; 4) Water Treatment Module; 5) Power supply and Control unit; 6) Rack mount. The developed 2{sup nd} generation rack-mounted alkaline electrolyser system has been installed and demonstrated for 18 month in a college (H2College) with 66 apartments. A number of measurements were performed on the system installed in H2College. No measurements on the overall system efficiency were conducted. However measurement on the stack showed a stack efficiency of 86.5% at a current density of 177mA/cm{sup 2} and a temperature of 74.4 deg. C at the hydrogen outlet. The system is estimated to have run roughly 2000h during the demonstration period. The demonstration of the 2{sup nd} generation alkaline electrolyser is considered a success for several reasons. While not all technical goals were reached, the research and development in the project have resulted in some very good solutions for most of the challenges in high pressure alkaline electrolysis. The concept of a rack mounted electrolyser was proven viable, and all critical aspects of the modularisation have been covered. (LN)

  17. Ultrastable α phase nickel hydroxide as energy storage materials for alkaline secondary batteries

    Science.gov (United States)

    Huang, Haili; Guo, Yinjian; Cheng, Yuanhui

    2018-03-01

    α Phase nickel hydroxide (α-Ni(OH)2) has higher theoretical capacity than that of commercial β phase Ni(OH)2. But the low stability inhibits its wide application in alkaline rechargeable batteries. Here, we propose a totally new idea to stabilize α phase Ni(OH)2 by introducing large organic molecule into the interlayer spacing together with doping multivalent cobalt into the layered Ni(OH)2 host. Ethylene glycol is served as neutral stabilizer in the interlayer spacing. Nickel is substituted by cobalt to increase the electrostatic attraction between layered Ni(OH)2 host and anion ions in the interlayer spacing. Polyethylene glycol (PEG-200) is utilized to design a three-dimensional network structure. This prepared α-Ni(OH)2-20 exhibits specific capacity as high as 334 mAh g-1and good structural stability even after immersing into strong alkaline zincate solution for 20 days. Ni(OH)2 electrode with a specific capacity of 35 mAh cm-2 is fabricated and used as positive electrode in zinc-nickel single flow batteries, which also shows good cycling stability. This result can provide an important guideline for the rational design and preparation of highly active and stable α phase Ni(OH)2 for alkaline secondary battery.

  18. Alkaline direct alcohol fuel cells

    Science.gov (United States)

    Antolini, E.; Gonzalez, E. R.

    The faster kinetics of the alcohol oxidation and oxygen reduction reactions in alkaline direct alcohol fuel cells (ADAFCs), opening up the possibility of using less expensive metal catalysts, as silver, nickel and palladium, makes the alkaline direct alcohol fuel cell a potentially low cost technology compared to acid direct alcohol fuel cell technology, which employs platinum catalysts. A boost in the research regarding alkaline fuel cells, fuelled with hydrogen or alcohols, was due to the development of alkaline anion-exchange membranes, which allows the overcoming of the problem of the progressive carbonation of the alkaline electrolyte. This paper presents an overview of catalysts and membranes for ADAFCs, and of testing of ADAFCs, fuelled with methanol, ethanol and ethylene glycol, formed by these materials.

  19. Efficient utilization of licorice root by alkaline extraction.

    Science.gov (United States)

    Ohno, Hirokazu; Miyoshi, Shozo; Araho, Daisuke; Kanamoto, Taisei; Terakubo, Shigemi; Nakashima, Hideki; Tsuda, Tadashi; Sunaga, Katsuyoshi; Amano, Shigeru; Ohkoshi, Emika; Sakagami, Hiroshi; Satoh, Kazue; Yamamoto, Masaji

    2014-01-01

    Compared to studies of water extracts of plants, those utilising alkaline extracts are limited. Both water and alkaline extracts from licorice root were compared regarding their biological activities. Licorice root was successively extracted first with water or alkaline solution (pH 9 or 12), and the alkaline (pH 12.0) extract was further separated into 50% ethanol-soluble and -insoluble fractions. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antibacterial activity against Porphyromonas gingivalis 381 was determined by turbidity assay. Cytochrome P-450 (CYP)3A4 activity was measured by β-hydroxylation of testosterone using human recombinant CYP3A4. Radical intensity of superoxide and hydroxyl radicals was determined by electron spin resonance spectroscopy. Alkaline extraction yielded slightly higher amounts of dried materials compared to water extraction. Alkaline extract showed higher anti-HIV and antibacterial activities, and similar magnitudes of CYP3A4 inhibitory and superoxide and hydroxyl radical-scavenging activities, compared to water extract. When alkaline extract was fractionated by 50% ethanol, anti-HIV activity was recovered from the insoluble fraction representing approximately 3% of the alkaline extract, whereas antibacterial activity was concentrated in the soluble fraction rich in glycyrrhizid acid, flavanones and chalcones. All extracts and sub-fractions led to bimodal hormetic dose-response (maximum hormetic response=238%) on the bacterial growth. The present study demonstrated the superiority of alkaline extraction over water extraction for preparing anti-HIV and antibacterial agents at higher yield from licorice root. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  20. Ion exchange behaviour of citrate and EDTA anions on strong and weak base organic ion exchangers

    International Nuclear Information System (INIS)

    Askarieh, M.M.; White, D.A.

    1988-01-01

    The exchange of citrate and EDTA ions with two strong base and two weak base exchangers is considered. Citrate and EDTA analysis for this work was performed using a colorimetric method developed here. The ions most selectively exchanged on the resins are H 2 cit - and H 2 EDTA 2- , though EDTA is generally less strongly sorbed on strong base resins. In contact with weak base resins, deprotonation of the resin occurs during ion exchange with a noticeable drop in solution pH. Although EDTA sorption can be reversed by nitric acid, citrate ions are significantly held on the resin at low pH. The exchange of citrate can be made reversible if bicarbonate is added to the initial solutions. Alkaline regeneration of exchangers loaded with EDTA proved to be very effective. (author)

  1. Comparative electrocatalytic oxidation of ethanol, ethylene glycol and glycerol in alkaline medium at Pd-decorated FeCo@Fe/C core-shell nanocatalysts

    CSIR Research Space (South Africa)

    Fashedemi, OO

    2014-05-01

    Full Text Available Electrocatalytic oxidation of alcohols in alkaline solutions is critical for the development of direct alkaline alcohol fuel cells (DAAFCs). This work investigated alcohol oxidation reaction (AOR) at a novel palladium-based core-shell nano catalyst...

  2. Degradation of polymers in an alkaline environment

    Energy Technology Data Exchange (ETDEWEB)

    Borges, P. G.; Thorpe, S. J.; Venter, R. D. [Toronto Univ., Toronto, ON (Canada)

    1999-10-01

    To introduce widespread use of hydrogen as a source of fuel, it is essential to significantly reduce the cost of electrolysers and fuel cells, preferably by substituting degradation-resistant low cost alternatives for traditional materials. An experimental apparatus for evaluating short-term degradation characteristics of polymers in 25 per cent potassium hydroxide aqueous solution at 70 and at 85 degrees C was constructed to determine changes in physical appearance, weight, volume and dimensions as a function of immersion time from 0 to 670 hours. Polymers that were part of this test included chlorinated polyvinyl chloride (CPVC), polypropylene (PP),and a polyurethane/polyester blend. Polypropylene demonstrated the greatest degradation resistance to the alkaline environment at both temperatures. CPVC discolored and the polyurethane/polyester blend deteriorated into smaller pieces when subjected to identical conditions. Resistance to degradation in an alkaline environment is a primary requirement for the selection of polymers for use as structural materials in alkaline water analyzers, which in turn is fundamental to the widespread adoption of a hydrogen economy. 6 refs., 13 figs.

  3. Analysis of the factors which have an influence on the reduction of residuary strengths due to alkaline solution in the interstitial mortars of concretes with aluminous cement Assessment of the risk limits in the case of roof beams

    Directory of Open Access Journals (Sweden)

    Goma Ginesta, Ferrán

    1995-06-01

    Full Text Available The scarce references which exist in the bibliography on this subject and their vagueness on the factors which have an influence on the reduction of the strength of aluminous cement concrete due to the effect of alkalinity, have not yet allowed the limits to be clearly seen which could give rise to a situation of risk in the structural elements due to this cause. A study is presented which endeavors to measure the quantitative influence of different parameters of the same or of a similar conditions to those presented in the usual types of concrete in existing beams with aluminous cement characteristic of our market. The parameters tested were: the influence of the concentration of free ions OH-, the class of alkaline ion, the temperature, the time, the presence or absence of CO2, the degree of conversion, the physical parameters, porosities, densities, etc., and the phases existing were determined by XRD, DTA and TG before and after the alkaline action. From the results obtained in numerous series of Rilem mortars and micro-mortars, it is possible to see the possibility of establishing the setting of parameters which define areas without risk.

    Las escasas referencias que existen en la bibliografía sobre este tema, y su identificación sobre los factores que tienen influencia sobre la disminución de resistencias en el hormigón de cemento aluminoso por efecto de la alcalinidad, no ha permitido aún ver claramente los limites que pueden dar lugar a una situación de riesgo en los elementos estructurales por esta causa. Se presenta un estudio que trata de medir la influencia cuantitativa de diferentes parámetros, con la misma o semejante magnitud que se presentan en los tipos usuales de hormigones de vigas existentes con cemento aluminoso propio de nuestro mercado. Los parámetros ensayados han sido: la influencia de la concentración de iones OH- libres, la clase de ion alcalino, la temperatura, el

  4. High temperature and pressure alkaline electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ganley, Jason C. [Department of Chemical Engineering, Howard University, 2013 Lewis K. Downing Hall, 2300 6th Street NW, Washington, DC 20059 (United States)

    2009-05-15

    This paper describes experimental work involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at high temperatures (up to 400 C) and under various pressures. A high-temperature alkaline electrolysis cell resistant to chemical attack from the highly corrosive electrolyte solution and capable of high-pressure operation was designed and tested. The cell was constructed with a Monel {sup registered} alloy housing and cathode, while various anode materials were compared. The anode materials tested included nickel, Monel alloy, lithiated nickel, and cobalt-plated nickel. The advantages of operating an alkaline electrolysis cell at high temperatures include increasing the ionic conductivity of the electrolyte and enhancing the rates of electrochemical reactions at the electrode surfaces. Cell operation with increasing steam partial pressure over the solution is also shown to enhance cell performance. The prudent selection of anode material also impacts the required terminal potential for a given current density, and consequently the cell's electric power efficiency. The best cell performance was achieved using a cobalt-plated nickel anode at a temperature of 400 C and a steam partial pressure of 8.7 MPa. (author)

  5. Fibrillation of Aspen by Alkaline Cold Pre-treatment and Vibration Milling

    Directory of Open Access Journals (Sweden)

    Kärt KÄRNER

    2016-09-01

    Full Text Available In this article an attempt to fibrillate aspen bleached chemi-thermo mechanical pulp (BCTMP fibre in an environmentally friendly way is reported. The effects of various NaOH, KOH, urea and ethanol aqueous solutions at lowered temperature were tested for pre-treatment. The pre-treatment was followed by vibration milling aiming to peel off outer cell wall layers and to fibrillate S2 layer of the aspen wood fibre. The effects of the treatments were evaluated by scanning electron microscopy (SEM. The results show that it is possible to fibrillate BCTMP aspen fibres by using alkaline aqueous solutions at low temperatures followed by a mechanical treatment. A strong dependence on fibrillation of cellulose on temperature, time and alkali concentration was established.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7412

  6. Geochemical modeling of the influence of silicate mineral alteration on alkalinity production and carbonate precipitation

    Science.gov (United States)

    Herda, Gerhard; Kraemer, Stephan M.; Gier, Susanne; Meister, Patrick

    2016-04-01

    as well as carbonates in porefluids under different pCO2 levels. In a second step, we will let the minerals react to a thermodynamically stable state and thereby observe the resulting alkalinity effect and the effect on carbonate precipitation. So far, modeling showed that saturation states of some of the most common clay minerals, including kaolinite, illite, montmorillonite and chlorite in a standard seawater solution strongly depend on silica and aluminum concentrations, but they show very little dependence on the pH. This is understandable since a congruent dissolution of clay minerals does not significantly increase or decrease the alkalinity. However, partial leaching of structural ions by incongruent dissolution/precipitation should have a strong effect on porewater alkalinity. Hence, substitution reactions will have to be simulated as part of this study. Calculated mineral alteration and rock-fluid interactions in deep sediments will contribute to a better understanding of carbonate diagenesis but also of long-term effects in subsurface CO2 storage reservoirs. Mavromatis et al. (2014) Chem. Geol. 385, 84-91. Parkhurst, D.L, and Appelo, C.A.J. (2013) U.S Geological Survey Techniques and Methods, book 6, chap. A43, 497 p. Wallmann et al. (2008) Geochim. Cosmochim. Acta 72, 3067-3090.

  7. Alkaline galvanic cells

    Energy Technology Data Exchange (ETDEWEB)

    Eisenberg, M.

    1993-06-01

    A battery is described having an anode, a cathode and an electrolyte with the anode having zinc or a zinc alloy as an active anodic material, the cathode having a metal oxide or hydroxide as an active cathodic material, and the electrolyte comprising a solution of a first salt formed by the reaction of one or more acids selected from the group consisting of boric acid, phosphoric acid and arsenic acid with an alkali or earth alkali hydroxide present in an amount to produce a stoichiometric, excess of said hydroxide to said acid in the range of 2.5 to 11.0 equivalents per liter, and a solution of a second salt which is a soluble alkali or earth alkali fluoride in an amount corresponding to a concentration range of 0.01 to 1.0 equivalents per liter of total solution.

  8. Effect of alkaline treated soybean meal on the performance, protein ...

    African Journals Online (AJOL)

    An experiment was conducted to evaluate the effect of alkaline treated soybean seeds on the performance, protein and energy efficiency of starter broilers. Soybean seeds were divided into 4 batches. The first batch was autoclaved at 100°C and the other batches soaked in aqueous solution of 3% concentration of sodium ...

  9. Preliminary note on the utitization of alkaline hydrogen peroxide ...

    African Journals Online (AJOL)

    The effect of alkaline hydrogen peroxide (AHp) treatment and urea supplementation on the feeding value of wheat straw was investigated in a 2x2 factorial experiment with sheep. Bales of wheat straw were dipped for a period of 24 h in an. AHP solution consisting of 1"/" hydrogen peroxide and 0,55% sodium hydroxide ...

  10. High-Efficiency Artificial Photosynthesis Using a Novel Alkaline Membrane Cell

    Science.gov (United States)

    Narayan, Sri; Haines, Brennan; Blosiu, Julian; Marzwell, Neville

    2009-01-01

    A new cell designed to mimic the photosynthetic processes of plants to convert carbon dioxide into carbonaceous products and oxygen at high efficiency, has an improved configuration using a polymer membrane electrolyte and an alkaline medium. This increases efficiency of the artificial photosynthetic process, achieves high conversion rates, permits the use of inexpensive catalysts, and widens the range of products generated by this type of process. The alkaline membrane electrolyte allows for the continuous generation of sodium formate without the need for any additional separation system. The electrolyte type, pH, electrocatalyst type, and cell voltage were found to have a strong effect on the efficiency of conversion of carbon dioxide to formate. Indium electrodes were found to have higher conversion efficiency compared to lead. Bicarbonate electrolyte offers higher conversion efficiency and higher rates than water solutions saturated with carbon dioxide. pH values between 8 and 9 lead to the maximum values of efficiency. The operating cell voltage of 2.5 V, or higher, ensures conversion of the carbon dioxide to formate, although the hydrogen evolution reaction begins to compete strongly with the formate production reaction at higher cell voltages. Formate is produced at indium and lead electrodes at a conversion efficiency of 48 mg of CO2/kilojoule of energy input. This efficiency is about eight times that of natural photosynthesis in green plants. The electrochemical method of artificial photosynthesis is a promising approach for the conversion, separation and sequestration of carbon dioxide for confined environments as in space habitats, and also for carbon dioxide management in the terrestrial context. The heart of the reactor is a membrane cell fabricated from an alkaline polymer electrolyte membrane and catalyst- coated electrodes. This cell is assembled and held in compression in gold-plated hardware. The cathode side of the cell is supplied with carbon

  11. Potassium salts of fatty acids as precipitating agents of alkaline earth metal ions

    International Nuclear Information System (INIS)

    Skrylev, L.D.; Sin'kova, L.A.

    1977-01-01

    Regularities have been studied of precipitation of ions of alkaline-earth elements with caprilate, pelargonate, caprinate, undecanate, laurate, tridecanate, myristate, pentadecanate, palmitate, and stearate of potassium. It has been shown that completeness of precipitation of metal ions is determined by the nature of alkaline-earth metal and potassium salt as well as by pH value and temperature of the solution. The study of temperature dependence of soaps of alkaline-earth metals makes it possible to calculate the heats of dissolution of laurates of alkaline-earth metals, and a change in entropy and free energy

  12. Determination of Cancer Cell-Based pH-Sensitive Fluorescent Carbon Nanoparticles of Cross-Linked Polydopamine by Fluorescence Sensing of Alkaline Phosphatase Activity on Coated Surfaces and Aqueous Solution.

    Science.gov (United States)

    Kang, Eun Bi; Choi, Cheong A; Mazrad, Zihnil Adha Islamy; Kim, Sung Han; In, Insik; Park, Sung Young

    2017-12-19

    The tumor-specific sensitive fluorescence sensing of cellular alkaline phosphatase (ALP) activity on the basis of host-guest specific and pH sensitivity was conducted on coated surfaces and aqueous states. Cross-linked fluorescent nanoparticles (C-FNP) consisting of β-cyclodextrin (β-CD)/boronic acid (BA) and fluorescent hyaluronic acid [FNP(HA)] were conjugated to fluorescent polydopamine [FNP(pDA)]. To determine the quenching effect of this system, hydrolysis of 4-nitrophenyl phosphate (NPP) to 4-nitrophenol (NP) was performed in the cavity of β-CD in the presence of ALP activated photoinduced electron transfer (PET) between NP and C-FNP. At an ALP level of 30-1000 U/L, NP caused off-emission of C-FNP because of their specific host-guest recognition. Fluorescence can be recovered under pH shock due to cleavage of the diol bond between β-CD and BA, resulting in release of NP from the fluorescent system. Sensitivity of the assays was assessed by confocal imaging not only in aqueous states, but also for the first time on coated surfaces in MDAMB-231 and MDCK cells. This novel system demonstrated high sensitivity to ALP through generation of good electron donor/acceptor pair during the PET process. Therefore, this fluorescence sensor system can be used to enhance ALP monitoring and cancer diagnosis on both coated surfaces and in aqueous states in clinical settings.

  13. Net alkalinity and net acidity 1: Theoretical considerations

    International Nuclear Information System (INIS)

    Kirby, Carl S.; Cravotta, Charles A.

    2005-01-01

    Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO 2 , and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined 'CO 2 -acidity' is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO 2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass-action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mgL -1 as CaCO 3 (based on pH and analytical concentrations of dissolved Fe II , Fe III , Mn, and Al in mgL -1 ):acidity calculated =50{1000(10 -pH )+[2(Fe II )+3(Fe III )]/56+2(Mn) /55+3(Al)/27}underestimates contributions from HSO 4 - and H + , but overestimates the acidity due to Fe 3+ and Al 3+ . However, these errors tend to approximately cancel each other. It is demonstrated that 'net alkalinity' is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the

  14. Sodic alkaline stress mitigation by exogenous melatonin in tomato needs nitric oxide as a downstream signal.

    Science.gov (United States)

    Liu, Na; Gong, Biao; Jin, Zhiyong; Wang, Xiufeng; Wei, Min; Yang, Fengjuan; Li, Yan; Shi, Qinghua

    2015-08-15

    The present study was designed to determine the interactive effect of exogenous melatonin and nitric oxide (NO) on sodic alkaline stress mitigation in tomato seedlings. It was observed that exogenous melatonin treatment elevated NO levels in alkaline-stressed tomato roots. However, exogenous NO had little effects on melatonin levels. Importantly, melatonin-induced NO generation was accompanied by increased tolerance to alkaline stress. Chemical scavenging of NO reduced melatonin-induced alkaline stress tolerance and defense genes' expression. However, inhibition of melatonin biosynthesis had a little effect on NO-induced alkaline stress tolerance. These results strongly suggest that NO, acting as a downstream signal, is involved in the melatonin-induced tomato tolerance to alkaline stress. This process creates a new signaling pathway for improving stress tolerance in plant. Copyright © 2015 Elsevier GmbH. All rights reserved.

  15. Reversible Hydrolysis Reaction with the Spore Photoproduct under Alkaline Conditions.

    Science.gov (United States)

    Adhikari, Surya; Lin, Gengjie; Li, Lei

    2016-09-16

    DNA lesions may reduce the electron density at the nucleobases, making them prone to further modifications upon the alkaline treatment. The dominant DNA photolesion found in UV-irradiated bacterial endospores is a thymine dimer, 5-thyminyl-5,6-dihydrothymine, i.e., the spore photoproduct (SP). Here we report a stepwise addition/elimination reaction in the SP hydrolysis product under strong basic conditions where a ureido group is added to the carboxyl moiety to form a cyclic amide, regenerating SP after eliminating a hydroxide ion. Direct amidation of carboxylic acids by reaction with amines in the presence of a catalyst is well documented; however, it is very rare for an amidation reaction to occur without activation. This uncatalyzed SP reverse reaction in aqueous solution is even more surprising because the carboxyl moiety is not a good electrophile due to the negative charge it carries. Examination of the base-catalyzed hydrolyses of two other saturated pyrimidine lesions, 5,6-dihydro-2'-deoxyuridine and pyrimidine (6-4) pyrimidone photoproduct, reveals that neither reaction is reversible even though all three hydrolysis reactions may share the same gem-diol intermediate. Therefore, the SP structure where the two thymine residues maintain a stacked conformation likely provides the needed framework enabling this highly unusual carboxyl addition/elimination reaction.

  16. Isolation of radioactive strontium from natural samples. Separation of strontium from alkaline and alkaline earth elements by means of mixed solvent anion exchange

    International Nuclear Information System (INIS)

    Grahek, Z.; Kosutic, K.; Lulic, S.; Kvastek, K.; Eskinja, I.

    1999-01-01

    This paper presents the results of studies which led to the procedures for the chromatographic separation of radioactive strontium from alkaline, earth-alkaline and other elements in natural samples, on columns filled with strong base anion exchangers using alcoholic solutions of nitric acid as eluents. It has been shown that potassium, caesium, calcium, barium, yttrium and strontium can be adsorbed on strong base anion exchangers of the Dowex and Amberlite type, which contain the quaternary ammonium group with nitrate as counter-ion, from solutions of nitric acid in alcohol. Adsorption strength increases in the order methanol 3 in methanol, while they are adsorbed from ethanol and propanol. The adsorption strength is influenced by the polarity of alcohol, by the concentration of nitrate and by pH. The strength with which strontium adsorbs on the exchangers increases in the interval from 0 to 0.25M NH 4 NO 3 in methanol, after which it starts to decrease. Strontium adsorbs to the exchangers from the alcoholic solution of ammonium nitrate twice as strongly as from the alcoholic solution of nitric acid, while a fraction of water in pure alcohol exceeding 10% prevents adsorption. In the mixture of alcohol and nitric acid, the adsorption strength for calcium and strontium increases with the increase of the volume fraction of alcohol with a lower dielectric constant. The rate and strength of adsorption of ions on the exchanger also increase in the series 0.25M HNO 3 in methanol 3 in ethanol 3 in 1-propanol for each individual ion, as well as in the Ca 3 in methanol, 0.25M HNO 3 in ethanol and 0.25M HNO 3 in propanol. Separation is also possible from alcohol mixtures. Strontium separation is most difficult from calcium, while the efficiency of separation increases with a decrease of the polarity of the used alcohol or alcohol mixture. The first group elements of the periodic table are not separated from each other in this way, while the elements of the second group are

  17. Actinide-Aluminate Speciation in Alkaline Radioactive Waste

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David L. Clark; Dr. Alexander M. Fedosseev

    2001-12-21

    Investigation of behavior of actinides in alkaline media containing AL(III) showed that no aluminate complexes of actinides in oxidation states (IIII-VIII) were formed in alkaline solutions. At alkaline precipitation IPH (10-14) of actinides in presence of AL(III) formation of aluminate compounds is not observed. However, in precipitates contained actinides (IIV)<(VI), and to a lesser degree actinides (III), some interference of components takes place that is reflected in change of solid phase properties in comparison with pure components or their mechanical mixture. The interference decreases with rise of precipitation PH and at PH 14 is exhibited very feebly. In the case of NP(VII) the individual compound with AL(III) is obtained, however it is not aluminate of neptunium(VII), but neptunate of aluminium(III) similar to neptunates of other metals obtained earlier.

  18. Reduction of nitrobenzene with alkaline ascorbic acid: Kinetics and pathways

    International Nuclear Information System (INIS)

    Liang, Chenju; Lin, Ya-Ting; Shiu, Jia-Wei

    2016-01-01

    Highlights: • Alkaline ascorbic acid (a.k.a. vitamin C) is capable of reductively degrading NB. • The pH above the pK a2 of ascorbic acid increases reductive electron transfer to NB. • The rate equation for the reactions between NB and AA is determined. • NSB, AZOXY, and AZO are identified as intermediates and aniline as a final product. • Alkaline pH is essential for AA remediation of NB contaminated soils. - Abstract: Alkaline ascorbic acid (AA) exhibits the potential to reductively degrade nitrobenzene (NB), which is the simplest of the nitroaromatic compounds. The nitro group (NO 2 − ) of NB has a +III oxidation state of the N atom and tends to gain electrons. The effect of alkaline pH ranging from 9 to 13 was initially assessed and the results demonstrated that the solution pH, when approaching or above the pK a2 of AA (11.79), would increase reductive electron transfer to NB. The rate equation for the reactions between NB and AA at pH 12 can be described as r = ((0.89 ± 0.11) × 10 −4 mM 1−(a + b) h −1 ) × [NB] a = 1.35 ± 0.10 [AA] b = 0.89 ± 0.01 . The GC/MS analytical method identified nitrosobenzene, azoxybenzene, and azobenzene as NB reduction intermediates, and aniline (AN) as a final product. These experimental results indicate that the alkaline AA reduction of NB to AN mainly proceeds via the direct route, consisting of a series of two-electron or four-electron transfers, and the condensation reaction plays a minor route. Preliminary evaluation of the remediation of spiked NB contaminated soils revealed that maintenance of alkaline pH and a higher water to soil ratio are essential for a successful alkaline AA application.

  19. Scanning electron microscopic and X-ray micro analysis on tooth enamel exposed to alkaline agents.

    Science.gov (United States)

    Taubee, Fabian; Steiniger, Frank; Nietzsche, Sandor; Norén, Jörgen G

    2010-01-01

    The background of this study comprises two clinical cases, where patients exposed to aerosols of an alkaline and surface active cleaning agent developed loss of enamel substance on their teeth, further resulting in loss of teeth and partially destroyed soft tissues. The alkaline cleaning agent consisted of potassium hydroxide and various surfactants. The purpose of this study was to investigate possible changes in morphology and composition in human teeth enamel exposed to alkaline solutions, by means of X-ray micro analysis (XRMA), FTIR-spectroscopic analyses and scanning electron microscopy (SEM). Extracted premolars, exposed to potassium hydroxide solutions and alkaline cleaning solution,were analyzed by means of XRMA and SEM. Enamel powder, exposed to cleaning solution, was analyzed by means of FTIR. The SEM analysis revealed an increased porosity of the enamel surface and partially loss of enamel substance after exposure to alkaline solutions. The XRMA analyses revealed a decrease in carbon concentration while phosphorous and calcium showed no marked changes. The FTIR analyses showed no significant changes in peak heights or peak positions for phosphate, carbonate or hydroxide. It was concluded that human teeth enamel exposed to alkaline solutions showed loss of organic substance, marked pores in enamel surface and loss of substance in the enamel surface.

  20. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or reservoirs with different sand lenses with high permeability contrast. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more crude oil than waterflooding from swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or reservoirs with high permeability contrast zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium-polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Gel solutions under dynamic conditions of linear corefloods showed similar stability to alkaline-surfactant-polymer solutions as in

  1. Activation of Alkaline Irrigation Fluids in Endodontics.

    Science.gov (United States)

    Walsh, Laurence J; George, Roy

    2017-10-23

    In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

  2. Activation of Alkaline Irrigation Fluids in Endodontics

    Science.gov (United States)

    George, Roy

    2017-01-01

    In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled. PMID:29065540

  3. Activation of Alkaline Irrigation Fluids in Endodontics

    Directory of Open Access Journals (Sweden)

    Laurence J. Walsh

    2017-10-01

    Full Text Available In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl and ethylenediaminetetraacetic acid (EDTA are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

  4. Priming effect of abscisic acid on alkaline stress tolerance in rice (Oryza sativa L.) seedlings.

    Science.gov (United States)

    Wei, Li-Xing; Lv, Bing-Sheng; Wang, Ming-Ming; Ma, Hong-Yuan; Yang, Hao-Yu; Liu, Xiao-Long; Jiang, Chang-Jie; Liang, Zheng-Wei

    2015-05-01

    Saline-alkaline stress is characterized by high salinity and high alkalinity (high pH); alkaline stress has been shown to be the primary factor inhibiting rice seedling growth. In this study, we investigated the potential priming effect of abscisic acid (ABA) on tolerance of rice seedlings to alkaline stress simulated by Na2CO3. Seedlings were pretreated with ABA at concentrations of 0 (control), 10, and 50 μM by root-drench for 24 h and then transferred to a Na2CO3 solution that did not contain ABA. Compared to control treatment, pretreatment with ABA substantially improved the survival rate of rice seedlings and increased biomass accumulation after 7 days under the alkaline condition. ABA application at 10 μM also alleviated the inhibitory effects of alkaline stress on the total root length and root surface area. Physiologically, ABA increased relative water content (RWC) and decreased cell membrane injury degree (MI) and Na(+)/K(+) ratios. In contrast, fluridone (an ABA biosynthesis inhibitor) decreased the RWC and increased MI in shoots under the alkaline conditions. These data suggest that ABA has a potent priming effect on the adaptive response to alkaline stress in rice and may be useful for improving rice growth in saline-alkaline paddy fields. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  5. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank

    This report provides the results of the 2nd Generation Alkaline Electrolysis project which was initiated in 2008. The project has been conducted from 2009-2012 by a consortium comprising Århus University Business and Social Science – Centre for Energy Technologies (CET (former HIRC)), Technical...

  6. Uranium(VI) retention by Ca-bentonite under (hyper)alkaline conditions

    Energy Technology Data Exchange (ETDEWEB)

    Philipp, Thimo; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

    2017-06-01

    The sorption behavior of U(VI) on Ca-bentonite was studied in saline, (hyper)alkaline solution via batch experiments. At pH 8.5-9.5 sorption is low in the presence of CO{sub 2} due to the formation of weakly sorbing uranyl carbonate species, which have been observed to dominate speciation up to pH 10 by time-resolved laser-induced fluorescence spectroscopy (TRLFS). In the pH region 10-12, U(VI) retention is almost complete. The retention can either be attributed to strongly sorbing uranyl hydroxo complexes or to a partial precipitation of uranium due to an altered solubility of U(VI) induced by ions leached out of the bentonite.

  7. Alkaline lixiviation of uranium in granitic pegmatite

    International Nuclear Information System (INIS)

    Jambor, S.

    1980-06-01

    The work described herein concerns the determination of the experimental optimum conditions for the alkaline lixiviation of uranium based on the following parameters: time, pH, temperature, density and grane size. The samples were obtained from the Supamo complex, near the Currupia river in the Piar District of the Bolivar State in Venezuela. They have a granitic composition and graphitic texture. The uranium was found in them as a secondary oxidized mineral of green-yellow colour localized in fractures fissures, intergranular spaces and also in the mica as. Secondary uranitite. The lixiviation process was carried out using Na 2 CO 3 /NaHCO 3 buffer solution and for 100 gr. samples the best values for an efficient process were found by using 170 mesh grane size and 500 ml of pH buffer at 70 0 C for a 24 hour time period. (author)

  8. Membranas biológicas homólogas preservadas em solução alcalina seguida de liofilização, glicerina a 98% e por liofilização para implantação em eqüinos Homologous biological membranes persevered in alkaline solution and lyophilized, glycerin 98% and by lyophilization for equines implantation

    Directory of Open Access Journals (Sweden)

    Valcinir Aloisio Scolla Vulcani

    2008-08-01

    to evaluate physicist-chemistries alterations in equines diaphragmatic tendineous centers implants submitted to alkaline solution and lyophilization treatment. The samples had been treated in alkaline solution for 24, 48, 72, 120 and 144 hours and lyophilized. It was analyzed the homogeneity, flexibility and resistance to the suture. After that, they had been submitted to the differential scanner calorimetry and to the scanner electronic microscopy. Samples of 72 hours in alkaline treatment, conserved in glycerin 98% and only lyophilized were implanted in recto abdominis internal fascia of equines. They were removed one, nine and 18 weeks post-implantation to evaluate the existence of tacks. It was verified that the homogeneity and flexibility are directly proportional to the increase of time of treatment in alkaline solution while the resistance is inversely proportional to the time increase, being 72 hour treatment intermediate for these characteristics. The differential scanner calorimetry showed that the treatment do not denature the present collagen in samples. The electronic microscopy showed that the increase of treatment time provides expansion of less dense zones of the material. In relation to the formation of tacks, the samples only lyophilized had presented maximum degree in the proposal classification followed for the conserved in glycerin 98% samples with average degree and the treated in alkaline solution and lyophilized samples had been classified in minimum degree. It was concluded that the treatment for 72 hours would be more appropriate for implantation and that the tissue integration with abdominal wall was better in relation to the samples lyophilized only and to the conserved in glycerin ones.

  9. Oxygen evolution on Co{sub 3}O{sub 4} and Li-doped Co{sub 3}O{sub 4} coated electrodes in an alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Bocca, C.; Cerisola, G.; Barbucci, A. [Genova Univ. (Italy). Inst. of Chemistry; Magnone, E. [Genova Univ. (Italy). INFM; Genova Univ. (Italy). Dept. of Chemistry and Industrial Chemistry

    1999-08-01

    The oxygen evolution reaction (OER) was investigated at 60{sup o}C in 15 wt% NaOH solution on Co{sub 3}O{sub 4}, Li-doped Co{sub 3}O{sub 4} and perovskite-type oxide (LaNiO{sub 3}) electrodes. Cobalt and Li-doped cobalt oxides were obtained by different preparation techniques and were applied to chemically-pickled nickel plates. The obtained phases were structurally characterized by X-ray powder diffraction. The electrodes were subjected to electrochemical measurements, before and after electrochemical ageing (21 days, 150 mA cm{sup -2}). The correlation between the coating preparations and their electrocatalytic activity was investigated. The efficiency of the studied electrodes seems to depend on the preparation method. Two Tafel slopes for the OER were observed in most cases. This behaviour was interpreted on the basis of a change in the valence state of the surface oxide. (author)

  10. Enzymatic Hydrolysis of Alkaline Pretreated Coconut Coir

    Directory of Open Access Journals (Sweden)

    Akbarningrum Fatmawati

    2013-06-01

    Full Text Available The purpose of this research is to study the effect of concentration and temperature on the cellulose and lignin content, and the reducing sugars produced in the enzymatic hydrolysis of coconut coir. In this research, the coconut coir is pretreated using 3%, 7%, and 11% NaOH solution at 60oC, 80oC, and 100oC. The pretreated coir were assayed by measuring the amount of cellulose and lignin and then hydrolysed using Celluclast and Novozyme 188 under various temperature (30oC, 40oC, 50oC and pH (3, 4, 5. The hydrolysis results were assayed for the reducing sugar content. The results showed that the alkaline delignification was effective to reduce lignin and to increase the cellulose content of the coir. The best delignification condition was observed at 11% NaOH solution and 100oC which removed 14,53% of lignin and increased the cellulose content up to 50,23%. The best condition of the enzymatic hydrolysis was obtained at 50oC and pH 4 which produced 7,57 gr/L reducing sugar. © 2013 BCREC UNDIP. All rights reservedReceived: 2nd October 2012; Revised: 31st January 2013; Accepted: 6th February 2013[How to Cite: Fatmawati, A., Agustriyanto, R., Liasari, Y. (2013. Enzymatic Hydrolysis of Alkaline Pre-treated Coconut Coir. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 34-39 (doi:10.9767/bcrec.8.1.4048.34-39[Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4048.34-39] | View in  |

  11. Effect of alkalinity on nitrite accumulation in treatment of coal chemical industry wastewater using moving bed biofilm reactor.

    Science.gov (United States)

    Hou, Baolin; Han, Hongjun; Jia, Shengyong; Zhuang, Haifeng; Zhao, Qian; Xu, Peng

    2014-05-01

    Nitrogen removal via nitrite (the nitrite pathway) is more suitable for carbon-limited industrial wastewater. Partial nitrification to nitrite is the primary step to achieve nitrogen removal via nitrite. The effect of alkalinity on nitrite accumulation in a continuous process was investigated by progressively increasing the alkalinity dosage ratio (amount of alkalinity to ammonia ratio, mol/mol). There is a close relationship among alkalinity, pH and the state of matter present in aqueous solution. When alkalinity was insufficient (compared to the theoretical alkalinity amount), ammonia removal efficiency increased first and then decreased at each alkalinity dosage ratio, with an abrupt removal efficiency peak. Generally, ammonia removal efficiency rose with increasing alkalinity dosage ratio. Ammonia removal efficiency reached to 88% from 23% when alkalinity addition was sufficient. Nitrite accumulation could be achieved by inhibiting nitrite oxidizing bacteria (NOB) by free ammonia (FA) in the early period and free nitrous acid in the later period of nitrification when alkalinity was not adequate. Only FA worked to inhibit the activity of NOB when alkalinity addition was sufficient. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  12. Alkalinity production in intertidal sands intensified by lugworm bioirrigation.

    Science.gov (United States)

    Rao, Alexandra M F; Malkin, Sairah Y; Montserrat, Francesc; Meysman, Filip J R

    2014-07-05

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O 2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO 3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer.

  13. Radiolysis of actinides and technetium in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H., Westinghouse Hanford

    1996-07-10

    The {gamma}-radiolysis of aerated alkaline aqueous solutions of Np(V), Np(VI), Pu(VI), Tc(IV), Tc(V), and TC(VII) was studied in the absence of additives and in the presence of CO{sub 3}{sup 2-}, NO{sub 3}{sup -}, NO{sub 2}{sup -}, EDTA, formate, and other organic compounds. The radiolytic reduction of Np(V), Np(VI), Pu(VI), and TC(VII) under different experimental conditions was examined in detail. The addition of EDTA, formate, and alcohols was found to considerably increase the radiation-chemical reduction yields. The formation of the Np(V) peroxo complex was observed in the {gamma}-radiolysis of alkaline aqueous solutions of Np (VI) in the presence of nitrate.

  14. Development of alkaline fuel cells.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  15. Use of natural mordenite to remove chromium (III) and to neutralize pH of alkaline waste waters.

    Science.gov (United States)

    Córdova-Rodríguez, Valduvina; Rodríguez-Iznaga, Inocente; Acosta-Chávez, Raquel María; Chávez-Rivas, Fernando; Petranovskii, Vitalii; Pestryakov, Alexey

    2016-01-01

    The natural mordenite from Palmarito de Cauto deposit (PZ), Cuba, was studied in this work as an ion exchanger to remove Cr(3+) cations from alkaline aqueous solutions at different pH and chromium concentrations. The mordenite stability under cyclic treatment processes with alkaline solutions and its capacity to decrease the pH of the solutions was also analyzed. It was shown that PZ removes Cr(3+) ions from alkaline solutions, and it happens independently of the starting chromium concentration and the pH of the exchange solution used. This material has an important neutralizing effect on alkaline solutions, expressed in a significant pH decrease from the early stages of the treatments. For solutions with initial pH equal to 11, it decreases to a value of around seven. The stability of this material is not affected significantly after continuous cyclic treatment with NaOH solution, which shows that mordenite, in particular from Palmarito de Cauto deposit, has high stability in alkaline solutions. The results are important as they suggest that natural zeolites may be of interest in treatments of alkaline industrial waste effluents.

  16. Effect of alkaline cleaning and activation on aluminum alloy 7075-T6

    International Nuclear Information System (INIS)

    Joshi, Simon; Fahrenholtz, William G.; O'Keefe, Matthew J.

    2011-01-01

    The effect of alkaline cleaning and activation on the composition and thickness of the oxide layer on aluminum alloy 7075-T6 was studied. E-pH diagrams were developed to predict the effect of alkaline cleaning and activation solutions on the stability of the oxide surface layers. The thickness of the native oxide layer was determined to be ∼30 nm by Auger electron spectroscopy depth profiling analysis. The outer ∼20 nm was rich in magnesium while the remaining ∼10 nm was rich in aluminum. Cleaning in a 9.1 pH alkaline solution was found to remove the magnesium-rich layer and leave behind an aluminum-rich oxide layer ∼10 nm thick. Activation in alkaline solutions of NaOH (pH > 12.9) or Na 2 CO 3 (pH > 11.5) produced an oxide that was ∼20 to 60 nm thick and rich in magnesium. Alkaline cleaning and activation altered the oxide composition and thickness making it possible for deposition of thicker cerium-based conversion coatings (∼100 to 250 nm) compared to only alkaline cleaning (∼30 nm), with application of one spray cycle of deposition solution.

  17. Analysis of longitudinal variations in North Pacific alkalinity

    Science.gov (United States)

    Fry, C.; Tyrrell, T.; Achterberg, E. P.

    2016-02-01

    Carbon measurements in the ocean lack the coverage of physical measurements, so approximate alkalinity is predicted where data is unavailable. Surface alkalinity in the North Pacific is poorly characterised by predictive algorithms. Understanding the processes affecting alkalinity in this area can improve the equations. We investigated the causes of regional variations in alkalinity using GLODAPv2. We tested different hypotheses for the causes of three longitudinal phenomena in surface ocean values of Alk*, a tracer of calcium carbonate cycling. These phenomena are: (a) an increase in Alk* from east to west at 50°N, (b) an increase in Alk* from west to east at 30°N, and (c) a lack of a strong increase in Alk* from west to east in the equatorial upwelling area. We found that the most likely cause of higher Alk* on the western side of the subpolar North Pacific (at 50°N) is that denser isopycnals with higher Alk* lie at shallower depths on the western side than the eastern side. At 30°N, the main cause of higher Alk* on the eastern side of the basin is upwelling along the continental shelf of southwestern North America. Along the equator, our analyses suggest that the absence of a strong east-west trend is because the more intense upwelling on the eastern side of the basin does not, under normal conditions, lead to strong elevation of Alk*. However, surface Alk* is more strongly elevated in the eastern Equatorial Pacific during negative phases of the El-Nino-Southern Oscillation, probably because the upwelled water comes from greater depth at these times.

  18. Faster onset and more comfortable injection with alkalinized 2% lidocaine with epinephrine 1:100,000.

    Science.gov (United States)

    Malamed, Stanley F; Tavana, Susan; Falkel, Mic

    2013-02-01

    The pH of lidocaine with epinephrine in dental cartridges ranges between 2.9 and 4.4. In this pH range, less than 0.1% of the anesthetic is in the de-ionized or "active" form. The acidity of the anesthetic may delay onset and contribute to injection pain. The study compared anesthetic latency and injection pain for alkalinized versus non-alkalinized anesthetic in inferior alveolar nerve blocks (IANBs). The study buffered the anesthetic directly in the cartridges using a mixing pen device. The study included 20 participants, each receiving one control and one test IANB injection. The control solution was non-alkalinized 2% lidocaine/epinephrine 1:100,000 at pH 3.85. The test solution was 2% lidocaine/ epinephrine 1:100,000 alkalinized to pH 7.31. Latency was measured using endodontic ice confirmed with an electric pulp tester (EPT), and injection pain was measured using a visual analog scale (VAS). ONSET TIME: With the alkalinized anesthetic, 71% of participants achieved pulpal analgesia in 2 minutes or less. With non-alkalinized anesthetic, 12% achieved pulpal analgesia in 2 minutes or less (P = 0.001). The average time to pulpal analgesia for the non-alkalinized anesthetic was 6:37 (range 0:55 to 13:25). Average time to pulpal analgesia for alkalinized anesthetic was 1:51 (range 0:11 to 6:10) (P = 0.001). INJECTION PAIN RESULTS: 72% of the participants rated the alkalinized injection as more comfortable, 11% rated the non-alkalinized injection as more comfortable, and 17% reported no preference (P = 0.013). Forty-four percent of the patients receiving alkalinized anesthetic rated the injection pain as zero ("no pain") on a 100-mm VAS, compared to 6% of the patients who received non-alkalinized anesthetic (P = 0.056). Alkalinizing lidocaine with epinephrine toward physiologic pH immediately before injection significantly reduces anesthetic onset time and increases the comfort of the injection. Clinicians can begin procedures more quickly and give a more comfortable

  19. Coupling the Alkaline-Surfactant-Polymer Technology and the Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or reservoirs with different sand lenses with high permeability contrast. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more crude oil than waterflooding froin swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or reservoirs with high permeability contrast zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium-polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Gel solutions under dynamic conditions of linear corefloods showed similar stability to alkaline-surfactant-polymer solutions as in

  20. Application conditions for ester cured alkaline phenolic resin sand

    Directory of Open Access Journals (Sweden)

    Ren-he Huang

    2016-07-01

    Full Text Available Five organic esters with different curing speeds: propylene carbonate (i.e. high-speed ester A; 1, 4-butyrolactone; glycerol triacetate (i.e. medium-speed ester B; glycerol diacetate; dibasic ester (DBE (i.e. low-speed ester C, were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin (including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand and the amount of added organic ester and curing temperature were investigated. The results indicated the following: (1 The optimal added amount of organic ester should be 25wt.%-30wt.% of alkaline phenolic resin and it must be above 20wt.%-50 wt.% of the organic ester hydrolysis amount. (2 High-speed ester A (propylene carbonate has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin. (3 High-speed ester A, medium-speed ester B (glycerol triacetate and low-speed ester C (dibasic ester, i.e., DBE should be used below 15 ìC, 35 ìC and 50 ìC, respectively. High-speed ester A or low-speed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand. (4 There should be a suitable solid content (generally 45wt.%-65wt.% of resin, alkali content (generally 10wt.%-15wt.% of resin and viscosity of alkaline phenolic resin (generally 50-300 mPa≤s in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

  1. Pollution control and resource reuse for alkaline hydrometallurgy of amphoteric metal hazardous wastes

    CERN Document Server

    Youcai, Zhao

    2017-01-01

    This book provides a comprehensive description of alkaline hydrometallurgy of amphoteric metal hazardous wastes. Topics focus on leaching of zinc and lead hazardous wastes, purification of leach solution of zinc and lead, electrowinning of zinc and lead from purified alkaline solutions, chemical reactions taking place in the production flowsheets, thermodynamic and spent electrolyte regeneration, alkaline hydrometallurgy of low-grade smithsonite ores, recovery of molybdenum and tungsten using ion flotation and solvent extraction processes and their application in chemical synthesis of Nb and Ta inorganic compounds, and industrial scale production of 1500-2000 t/a zinc powder using alkaline leaching–electrowinning processes. Processes described are cost-effective, generate lesser secondary pollutants, and have been applied widely in China. Readers that will find the book appealing include solid waste engineers, environmental managers, technicians, recycling coordinators, government officials, undergraduates ...

  2. On the capacity to the complexing of alkaline earth metal and magnesium chromates

    International Nuclear Information System (INIS)

    Orekhov, O.L.

    1978-01-01

    Considered is the capacity to the complexing of magnesium chromates and alkaline earth metal chromates with ammonium chromates in aqueous solutions. It has been established that the complexing of alkaline earth metal and magnesium chromates is effected by a nature of initial salts as well as their solubilities and the presence of crystallization water. Capacity of magnesium ions and alkaline rare earth metals to the complexing decreases in a series of Mg-Ca-Sr-Ba. Ca complexes exceed magnesium derivatives in respect of stability

  3. Use of polysulfides of alkali and alkaline-earth metals to obtain highly dispersed sulfur

    International Nuclear Information System (INIS)

    Massalimov, I.A.; Vikhareva, I.N.; Kireeva, M.S.

    2008-01-01

    Possibilities of obtaining polysulfides of alkali and alkaline earth metals (M is Na, K, Ca, Sr, Ba) in aqueous solutions were considered. The composition of the polysulfides and their concentration in solutions were found. The efficiencies of application of highly dispersed sulfur, produced from calcium polysulfide, and colloid sulfur as a fungicide were compared [ru

  4. Ocean Acidification: Coccolithophore's Light Controlled Effect on Alkalinity

    Science.gov (United States)

    Dobbins, W.

    2015-12-01

    Coccolithophorids, which play a significant role in the flux of calcite and organic carbon from the photic region to deeper pelagic and benthic zones, are potentially far more useful than siliceous phytoplankton for ocean fertilization projects designed to sequester CO2. However, the production of H+ ions during calcification (HCO3 + Ca+ —> CaCO3 + H+) has resulted in localized acidification around coccolithophore blooms. It has been hypothesized that under the correct light conditions photosynthesis could proceed at a rate such that CO2 is removed in amounts equimolar or greater than the H+ produced by calcification, allowing stable or increasing alkalinity despite ongoing calcification. Previously, this effect had not been demonstrated under laboratory conditions. Fifteen Emiliania huxleyi cultures were separated into equal groups with each receiving: 0, 6, 12, 18, or 24 hours of light each day for 24 days. Daily pH, cell density, and temperature measurements revealed a strong positive correlation between light exposure and pH, and no significant decline in pH in any of the cultures. Alkalinity increases were temperature independent and not strongly correlated with cell density, implying photosynthetic removal of carbon dioxide as the root cause. The average pH across living cultures increased from 7.9 to 8.3 over the first week and changed little for the reminder of the 24-day period. The results demonstrate coccolithophorids can increase alkalinity across a broad range of cell densities, despite the acidification inherent to the calcification process. If the light-alkalinity effect reported here proves scalable to larger cultures, Emiliania huxleyi are a strong candidate for carbon sequestration via targeted ocean fertilization.

  5. "Supergreen" Renewables: Integration of Mineral Weathering Into Renewable Energy Production for Air CO2 Removal and Storage as Ocean Alkalinity

    Science.gov (United States)

    Rau, G. H.; Carroll, S.; Ren, Z. J.

    2015-12-01

    Excess planetary CO2 and accompanying ocean acidification are naturally mitigated on geologic time scales via mineral weathering. Here, CO2 acidifies the hydrosphere, which then slowly reacts with silicate and carbonate minerals to produce dissolved bicarbonates that are ultimately delivered to the ocean. This alkalinity not only provides long-term sequestration of the excess atmospheric carbon, but it also chemically counters the effects of ocean acidification by stabilizing or raising pH and carbonate saturation state, thus helping rebalance ocean chemistry and preserving marine ecosystems. Recent research has demonstrated ways of greatly accelerating this process by its integration into energy systems. Specifically, it has been shown (1) that some 80% of the CO2 in a waste gas stream can be spontaneously converted to stable, seawater mineral bicarbonate in the presence of a common carbonate mineral - limestone. This can allow removal of CO2 from biomass combustion and bio-energy production while generating beneficial ocean alkalinity, providing a potentially cheaper and more environmentally friendly negative-CO2-emissions alternative to BECCS. It has also been demonstrated that strong acids anodically produced in a standard saline water electrolysis cell in the formation of H2 can be reacted with carbonate or silicate minerals to generate strong base solutions. These solutions are highly absorptive of air CO2, converting it to mineral bicarbonate in solution. When such electrochemical cells are powered by non-fossil energy (e.g. electricity from wind, solar, tidal, biomass, geothermal, etc. energy sources), the system generates H2 that is strongly CO2-emissions-negative, while producing beneficial marine alkalinity (2-4). The preceding systems therefore point the way toward renewable energy production that, when tightly coupled to geochemical mitigation of CO2 and formation of natural ocean "antacids", forms a high capacity, negative-CO2-emissions, "supergreen

  6. High-Tc superconducting materials in Y-Ba-Cu-O system with the dopants of alkaline metals

    International Nuclear Information System (INIS)

    Kuznetsov, M.V.

    1996-01-01

    The dopants of alkaline metals being introduced into the system Y-Ba-Cu-O do not greatly effect the value of T c . The dopants of alkaline metals lead to the formation of new super-conducting structures o the solid solutions types incorporating an alkaline metal; however, the region of homogeneity of these solutions are different due to the variety of conditions and methods of synthesis. Super-conducting structures, containing an alkaline metal, are characterized by the lowered content of oxygen in comparison with the system YBa 2 Cu 3 O 7-y . Probably, the presence of an alkaline metal in the structure of super-conducting system Y-Ba-Cu-O promotes the retaining of an orthorhombic nature of the crystalline lattice of the product at any dopant concentration. 49 refs

  7. Histochemistry of placental alkaline phosphatase in preeclampsia

    OpenAIRE

    Shevade, Sapna Prashant; Arole, Vasanti; Paranjape, Vaishali Mohan; Bharambe, Vaishaly Kishore

    2016-01-01

    Objectives: Placental alkaline phosphatase (PALP) is synthesized in placenta and increases with gestational age. Alkaline phosphatase supports pregnancy and could play an essential role in nutrient supply and growth of the fetus. Preeclampsia is a systemic disorder which affects 5 to 7 percent of women worldwide and is a major cause for maternal and neonatal morbidity and mortality. As it has a major role in fetal growth, nutrition and defense mechanism study of alkaline phosphatase enzymatic...

  8. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D

    1999-01-01

    .... The subject low cost alkaline electrochemical capacitor designs are based upon titanium nitride electrodes which exhibit 125 mF/sq cm surface capacitance density and remarkable electrochemical...

  9. Corrosion of copper in alkaline chloride environments

    International Nuclear Information System (INIS)

    King, F.

    2002-08-01

    The available literature information on the corrosion and electrochemical behaviour of copper in alkaline environments has been reviewed. The purpose of the review was to assess the impact of an alkaline plume from cementitious material on the corrosion behaviour of a copper canister in an SKB-3 type repository. The effect of the evolution of the environmental conditions within the repository have been considered, including the effects of temperature, redox conditions, pore-water salinity and pH. If the pore-water pH increases prior to the establishment of anoxic conditions, the canister surface will passivate as the pore-water pH exceeds a value of ∼ pH 9. Passivation will result from the formation of a duplex Cu 2 O/Cu(OH) 2 film. The corrosion potential will be determined by the equilibrium potential for the Cu 2 O/Cu(OH) 2 couple under oxic conditions, or by the Cu/Cu 2 O redox couple under anoxic conditions (in the absence of sulphide). Pitting corrosion is only likely to occur early in the evolution of the repository environment, whilst the canister is still relatively cool ( 2 available to support localised corrosion, and prior to the increase in pore-water pH and salinity. The subsequent increase in canister surface temperature, pore-water pH and salinity, and decrease in O 2 will make pit initiation less likely, although the canister will remain passive provided the pore-water pH is maintained above pH 9. The higher the pore-water pH, the more strongly the canister is passivated and the less likely the surface is to undergo localised attack. If the pore-water salinity increases prior to the increase in pH, there could be a period of active canister corrosion before passivation occurs.Under these circumstances, the corrosion potential will be a true mixed potential, determine by the relative kinetics of Cu dissolution as CuCl 2 - and of the reduction of O 2 . The development of anoxic conditions and an increase in pore-water sulphide concentration will

  10. Carbon in bifunctional air electrodes in alkaline solution

    International Nuclear Information System (INIS)

    Tryk, D.; Aldred, W.; Yeager, E.

    1983-01-01

    Bifunctional O 2 electrodes can be used both to reduce and to generate O 2 in rechargeable metal-air batteries and fuel cells. The factors controlling the O 2 reduction and generation reactions in gas-diffusional bifunctional O 2 electrodes are discussed. The resistance of such electrodes, as established from voltammetry curves, has been found to increase markedly during anodic polarization and to be dependent upon the electrode fabrication technique. Carbon blacks with more graphitic structure than Shawinigan black have been found to be more resistant to electro-oxidation. The further extension of cycle life of bifunctional electrodes using carbon is critically dependent on finding more oxidation-resistant carbons that at the same time have other surface properties meeting the requirements for catalyzed gas-diffusion electrodes

  11. Electrochemistry in anisotropic etching of silicon in alkaline solutions

    NARCIS (Netherlands)

    Nguyen, Q.D.

    2007-01-01

    Etching is the process of using an acidic or caustic chemical to cut into unprotected areas of a particular material. Initially used in the 15th century for decorating plate armor and sword blades, the metal surface (typically steel or copper) was first covered with a wax-like material. Part of the

  12. ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE

    International Nuclear Information System (INIS)

    Clark-Deaborg, David

    2001-01-01

    Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am--the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting their solubility and sorption behavior in tanks, determining whether chemical separations are needed for waste treatment, and designing separations processes. Baseline washing of tank sludges with NaOH solutions is being proposed to reduce the volume of HLW. Alkaline pretreatment of HLW will be needed to remove aluminum [as NaAl(OH) 4 ] because it significantly reduces the HLW volume; however, aluminate [Al(OH) 4 - ] enhances actinide solubility via an unknown mechanism. Thus, alkaline wash residues may require an additional treatment to remove actinides. The results of this research will determine the nature TRU (Np, Pu, Am) speciation with aluminate anions under alkaline, oxidizing tank-like conditions. Specific issues to be addressed include solubility of these actinides, speciation in aluminate-containing alkaline supernatants, the role of actinide redox states on solubility, and partitioning between supernatant and solid phases, including colloids. Studies will include thermodynamics, kinetics, spectroscopy, electrochemistry, etc. It is already known, for example, that certain high valent forms of NF and Pu are very soluble under alkaline conditions due to the formation of anionic hydroxo complexes, AnO 2 (OH) 4 2- and AnO 2 (OH) 5 3- . The presence of aluminate ions causes the actinide solubilities to increase, although the exact species have only been determined during this program. We are continuing to characterize high-valent TRU elements bound to oxo, water, OH - , under waste-like and sludge washing conditions. These conditions are in the range of 1-3 M excess hydroxide, ∼0.2 M carbonate, ∼0.5 M aluminate, for a total sodium of 2-4 mols/kg. Molecular structure-specific probes

  13. Reduction of nitrobenzene with alkaline ascorbic acid: Kinetics and pathways

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chenju, E-mail: cliang@nchu.edu.tw [Department of Environmental Engineering, National Chung Hsing University 250, Kuo-kuang Road, Taichung 402, Taiwan (China); Lin, Ya-Ting [Department of Environmental Engineering, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan (China); Shiu, Jia-Wei [Department of Environmental Engineering, National Chung Hsing University 250, Kuo-kuang Road, Taichung 402, Taiwan (China)

    2016-01-25

    Highlights: • Alkaline ascorbic acid (a.k.a. vitamin C) is capable of reductively degrading NB. • The pH above the pK{sub a2} of ascorbic acid increases reductive electron transfer to NB. • The rate equation for the reactions between NB and AA is determined. • NSB, AZOXY, and AZO are identified as intermediates and aniline as a final product. • Alkaline pH is essential for AA remediation of NB contaminated soils. - Abstract: Alkaline ascorbic acid (AA) exhibits the potential to reductively degrade nitrobenzene (NB), which is the simplest of the nitroaromatic compounds. The nitro group (NO{sub 2}{sup −}) of NB has a +III oxidation state of the N atom and tends to gain electrons. The effect of alkaline pH ranging from 9 to 13 was initially assessed and the results demonstrated that the solution pH, when approaching or above the pK{sub a2} of AA (11.79), would increase reductive electron transfer to NB. The rate equation for the reactions between NB and AA at pH 12 can be described as r = ((0.89 ± 0.11) × 10{sup −4} mM{sup 1−(a} {sup +} {sup b)} h{sup −1}) × [NB]{sup a} {sup =} {sup 1.35} {sup ±} {sup 0.10}[AA]{sup b} {sup =} {sup 0.89} {sup ±} {sup 0.01}. The GC/MS analytical method identified nitrosobenzene, azoxybenzene, and azobenzene as NB reduction intermediates, and aniline (AN) as a final product. These experimental results indicate that the alkaline AA reduction of NB to AN mainly proceeds via the direct route, consisting of a series of two-electron or four-electron transfers, and the condensation reaction plays a minor route. Preliminary evaluation of the remediation of spiked NB contaminated soils revealed that maintenance of alkaline pH and a higher water to soil ratio are essential for a successful alkaline AA application.

  14. Alkaline and alkaline earth metal phosphate halides and phosphors

    Science.gov (United States)

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  15. Chemical nickel plating in tartrate solutions with borohydride reducing agent

    International Nuclear Information System (INIS)

    Plokhov, V.A.

    1986-01-01

    The authors investigate the influence of various factors on the rate of chemical nickel plating in strongly alkaline tartrate solutions with a borohydride reducing agent. After 30 min of the process of nickel plating, the final concentration of sodium borohydride decreases to 0.26 g/liter, leading to stoppage of the process. The nickel plating process can be intensified by increasing the concentration of sodium hydroxide in the solution, suppressing hydrolysis of borohydride, and also by introducing additives which suppress hydrolysis of borohydride. For chemical deposition of nickel-boron coatings from tartrate solutions the authors recommend the following composition (g/liter): nickel chloride 15-25, Rochelle salt 450-550, sodium hydroxide 140-160, sodium borohydride 0.8-1.0, thallium nitrate 0.003-0.008. The process temperature is 92-95 C, and the deposition rate is 4-6 um/h

  16. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Mahna, S.K.; Bhargava, Anubha; Mohan, Lalit

    1990-01-01

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10 -6 , 10 -5 , 10 -4 and 10 -3 M) of sodium azide (NaN 3 ) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M 2

  17. Treatment of chlorofluorocarbons in alcohol solutions by γ-irradiation

    International Nuclear Information System (INIS)

    Shimokawa, Toshinari; Nakagawa, Seiko; Sawai, Teruko

    1995-01-01

    A study was done on dechlorination of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC113) in neutral and alkaline alcohol solutions by means of γ-irradiation. The dechlorination yield (G (Cl - )) was found to depend on the kind of alcohol used as solvents and the presence of hydroxide ion. The order of G (Cl - ) value in alkaline solution was isopropyl alcohol>> ethyl alcohol > methyl alcohol. It was suggested that the high yield obtained in alkaline isopropyl alcohol solution is explained by a chain process in dechlorination reaction. In case of alkaline isopropyl alcohol solution, CFC113 was dechlorinated to lower chlorinated ethane, and 1,1-dichloro-1,2,2-trifluoroetane was a main product. We have discussed on the chain dechlorination mechanism in alkaline isopropyl alcohol solution. (author)

  18. catalysed oxidation of atenolol by alkaline permanganate

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength of 0⋅30 mol dm3 has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline medium exhibits 1 : 8 stoichiometry.

  19. Increased liver alkaline phosphatase and aminotransferase ...

    African Journals Online (AJOL)

    The effect of daily, oral administration of ethanolic extract of Khaya senegalensis stem bark (2mg/kg body weight) for 18days on the alkaline phosphatase, aspartate and alanine aminotransferase activities of rat liver and serum were investigated. Compared with the control, the activities of liver alkaline phosphatase (ALP), ...

  20. Alkaline Phosphatases From Camel Small Intestine | Fahmy ...

    African Journals Online (AJOL)

    Camel intestinal alkaline phosphatase have been purified and characterized. The purification was carried out by chromatography on DEAE-cellulose. Five intestinal alkaline phosphatase isoenzymes (IAP1 to IAP5) were obtained. IAP2 and IAP5 with the highest activity levels were purified to homogeneity by Sephacryl ...

  1. Handbook of Indigenous Foods Involving Alkaline Fermentation

    NARCIS (Netherlands)

    Sarkar, P.K.; Nout, M.J.R.

    2014-01-01

    This book details the basic approaches of alkaline fermentation, provides a brief history, and offers an overview of the subject. The book discusses the diversity of indigenous fermented foods involving an alkaline reaction, as well as the taxonomy, ecology, physiology, and genetics of predominant

  2. Corrosion of uncoated and oxide-coated basalt fibre in different alkaline media

    International Nuclear Information System (INIS)

    Rybin, V.A.; Utkin, A.V.; Baklanova, N.I.

    2016-01-01

    Highlights: • Alkaline corrosion of uncoated and coated basalt fibre in alkali media was studied. • Degradation of the fibre involves the dissolution of alumosilicate network in alkali media. • Insoluble shell from iron and calcium hydroxides and carbonates is formed. • Zirconia and titania coatings slow down the corrosion of basalt fibre significantly. - Abstract: The corrosion behaviour of the zirconium dioxide and titanium dioxide coated basalt fibre in sodium and calcium hydroxide solutions was studied. The morphology, elemental, phase composition of fibre before and after exposure to alkaline media was examined by different analytical techniques. It was shown that the oxide coatings slow down corrosion, and zirconium dioxide slows down corrosion of basalt fibre to a higher extent than titanium dioxide. The morphology and composition of solid corrosion products depend on a type of alkaline medium. The schemes of corrosion for the uncoated and coated basalt fibres in alkaline media were proposed.

  3. Mega-solubility of quartz resulting from highly alkaline fluids produced by dissolved albite in H2O at deep crustal conditions

    Science.gov (United States)

    Makhluf, A. R.; Manning, C. E.

    2017-12-01

    Models of H2O-rich fluids equilibrated with rocks at high P and T fail to predict the high solubilities observed experimentally, chiefly because thermodynamic data for the most abundant solutes is lacking. We investigated the effects of dissolved albite (Ab) on the solubility of quartz (Qz) at 1.0 GPa and 675-900 °C using a piston-cylinder apparatus to quantify possible mineral buffering or enhancement effects. We found a very large enhancement effect on the solubility of Qz when dissolved in dilute aqueous Ab solutions. SiO2 concentrations are similar to Qz solubility in strongly alkaline KOH solutions. At the highest temperature of 900 °C, we found that the solubility of Qz in 1.0 molal Ab solution increases by of factor of 4.5 over that in pure H2O, which corresponds to 10.7 molal SiO2. The nearly identical solubility of Qz in KOH(aq) and Ab solutions of the same concentration, P, and T, strongly suggest that NaOH(aq) liberated from NaAlSi3O8 in H2O fluids effects SiO2 solubility in a similar manner to that of KOH(aq). The deprotonated silica dimer was found to be a key species responsible for the high solubility of Qz in KOH(aq) and is likely responsible for the high solubility of Qz in Ab solutions. While the binaries Qz-H2O, Ab-H2O, and Qz-Ab are well known at 1.0 GPa, little data exists on the ternary system. The new results help quantify the ternary relations in the Ab-Qz-H2O system, which can be used as a simple model for liquid-vapor immiscibility granitic magmas. In addition, these highly alkaline solute-rich aqueous fluids suggest a mechanism for Ab-Qz metasomatism in subduction zones, such as in the Catalina schist (Bebout and Barton 1993), which provides an alternative to high P-T magmas. Our results show that subduction zone and metasomatic fluids may be much more alkaline and have significantly higher dissolving power than previously thought.

  4. Alkaline Phosphatase, Soluble Extracellular Adenine Nucleotides, and Adenosine Production after Infant Cardiopulmonary Bypass.

    Science.gov (United States)

    Davidson, Jesse A; Urban, Tracy; Tong, Suhong; Twite, Mark; Woodruff, Alan; Wischmeyer, Paul E; Klawitter, Jelena

    2016-01-01

    Decreased alkaline phosphatase activity after infant cardiac surgery is associated with increased post-operative cardiovascular support requirements. In adults undergoing coronary artery bypass grafting, alkaline phosphatase infusion may reduce inflammation. Mechanisms underlying these effects have not been explored but may include decreased conversion of extracellular adenine nucleotides to adenosine. 1) Evaluate the association between alkaline phosphatase activity and serum conversion of adenosine monophosphate to adenosine after infant cardiac surgery; 2) assess if inhibition/supplementation of serum alkaline phosphatase modulates this conversion. Pre/post-bypass serum samples were obtained from 75 infants alkaline phosphatase and CD73. Low and high concentration 13C5-adenosine monophosphate (simulating normal/stress concentrations) were used. Effects of alkaline phosphatase supplementation on adenosine monophosphate clearance were also assessed. Changes in serum alkaline phosphatase activity were strongly correlated with changes in 13C5-adenosine production with or without CD73 inhibition (r = 0.83; palkaline phosphatase activity (≤80 U/L) generated significantly less 13C5-adenosine, particularly in the presence of high concentration 13C5-adenosine monophosphate (10.4μmol/L vs 12.9μmol/L; p = 0.0004). Inhibition of alkaline phosphatase led to a marked decrease in 13C5-adenosine production (11.9μmol/L vs 2.7μmol/L; palkaline phosphatase or high dose bovine intestinal alkaline phosphatase doubled 13C5-adenosine monophosphate conversion to 13C5-adenosine (pAlkaline phosphatase represents the primary serum ectonucleotidase after infant cardiac surgery and low post-operative alkaline phosphatase activity leads to impaired capacity to clear adenosine monophosphate. AP supplementation improves serum clearance of adenosine monophosphate to adenosine. These findings represent a potential therapeutic mechanism for alkaline phosphatase infusion during cardiac

  5. Rb-Sr age of the Sivamalai alkaline complex, Tamil Nadu

    International Nuclear Information System (INIS)

    Subba Rao, T.V.; Narayana, B.L.; Gopalan, K.

    1994-01-01

    The Sivamalai alkaline complex comprises ferro-, pyroxene- hornblende-and nepheline-syenites. Field relations show that the nepheline syenites followed the emplacement of non-feldspathoidal syenites. Mineralogical data on the syenite suite have been reviewed. The Sivamalai alkaline rocks are not strongly enriched in rare-earth elements like most miaskites. Rb-Sr isotopic analyses of a suite of six samples from the various members of the complex define an isochron corresponding to an age of 623 ± 21 Ma (2σ) and initial Sr ratio of 0.70376 ± 14 (2σ). This is consistent with a model of fractional crystallization of a parent magma derived from an upper mantle source with apparently no isotopic evidence for more than one magma source for the complex. The Sivamalai alkaline complex represents a Pan-African alkaline magmatic event in the southern granulite terrane of peninsular India. (author). 26 refs., 4 figs., 4 tabs

  6. Tungsten Recovery from Spent SCR Catalyst Using Alkaline Leaching and Ion Exchange

    Directory of Open Access Journals (Sweden)

    Wen-Cheng Wu

    2016-10-01

    Full Text Available The recovery of tungsten (W from a honeycomb-type spent selective catalytic reduction (SCR catalyst using an alkaline leaching–ion exchange method was investigated. Spent SCR catalyst mainly consists of TiO2 and other oxides (6.37% W, 1.57% vanadium (V, and 2.81% silicon (Si, etc.. The ground catalyst was leached at the optimal conditions, as follows: NaOH concentration of 0.3 kg/kg of catalyst, pulp density of 3%, leaching temperature of 70 °C, particle size of −74 μm, and leaching time of 30 min. In this study, the leaching rate values of V and W under the above conditions were 87 wt %, and 91 wt %, respectively. The pregnant solution was then passed through a strong base anion exchange resin (Amberlite IRA900. At high pH conditions, the use of strong base anion exchange resin led to selective loading of divalent WO42− from the solution, because the fraction of two adjacent positively-charged sites on the IRA900 resin was higher and separate from the coexisting VO43−. The adsorbed W could then be eluted with 1 M NaCl + 0.5 M NaOH. The final concentrated W solution had 8.4 g/L of W with 98% purity. The application of this process in industry is expected to have an important impact on the recovery of W from secondary sources of these metals.

  7. Application of urea dosing for alkalinity supply during anaerobic digestion of vinasse.

    Science.gov (United States)

    Boncz, M A; Formagini, E L; Santos, L da S; Marques, R D; Paulo, P L

    2012-01-01

    Pushed by demand for renewable energy, the ethanol industry in Brazil is expanding. However, production of 1 m(3) of ethanol generates around 13 m(3) of liquid residues (vinasse), so this expansion results in an increasing need for a more adequate destination of these residues. Nowadays the vinasse is dispersed on the sugar cane fields in the practice of fertirrigation, but anaerobic digestion of this residue may be a better solution, additionally offering an alternative source of energy, able to complement hydroelectric power supply in the dry season. However, when trying to digest vinasse at reduced hydraulic retention times, complications arise from its strong tendency toward acidification, upsetting the fragile balance of transformations normally occurring under anaerobic conditions. For successful operation of an anaerobic treatment process with acceptable hydraulic residence times, increasing alkalinity levels inside the reactor is neces-sary. In the present work we show that pH regulation by means of urea dosing, in spite of the risk posed by ammonia toxicity towards methanogenic biomass, can be a viable alternative to avoid vinasse acidification. The ammonia formed in urea conversion remains in solution, rather than escaping to the biogas, and so its use as fertiliser can offset its cost of application in the process.

  8. Alkaline Phosphatase: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/alkalinephosphatase.html Alkaline Phosphatase To use the sharing features on this page, please enable JavaScript. What is an Alkaline Phosphatase Test? An alkaline phosphatase (ALP) test measures ...

  9. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  10. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  11. Multisystemic functions of alkaline phosphatases.

    Science.gov (United States)

    Buchet, René; Millán, José Luis; Magne, David

    2013-01-01

    Human and mouse alkaline phosphatases (AP) are encoded by a multigene family expressed ubiquitously in multiple tissues. Gene knockout (KO) findings have helped define some of the precise exocytic functions of individual isozymes in bone, teeth, the central nervous system, and in the gut. For instance, deficiency in tissue-nonspecific alkaline phosphatase (TNAP) in mice (Alpl (-/-) mice) and humans leads to hypophosphatasia (HPP), an inborn error of metabolism characterized by epileptic seizures in the most severe cases, caused by abnormal metabolism of pyridoxal-5'-phosphate (the predominant form of vitamin B6) and by hypomineralization of the skeleton and teeth featuring rickets and early loss of teeth in children or osteomalacia and dental problems in adults caused by accumulation of inorganic pyrophosphate (PPi). Enzyme replacement therapy with mineral-targeting TNAP prevented all the manifestations of HPP in mice, and clinical trials with this protein therapeutic are showing promising results in rescuing life-threatening HPP in infants. Conversely, TNAP induction in the vasculature during generalized arterial calcification of infancy (GACI), type II diabetes, obesity, and aging can cause medial vascular calcification. TNAP inhibitors, discussed extensively in this book, are in development to prevent pathological arterial calcification. The brush border enzyme intestinal alkaline phosphatase (IAP) plays an important role in fatty acid (FA) absorption, in protecting gut barrier function, and in determining the composition of the gut microbiota via its ability to dephosphorylate lipopolysaccharide (LPS). Knockout mice (Akp3 (-/-)) deficient in duodenal-specific IAP (dIAP) become obese, and develop hyperlipidemia and hepatic steatosis when fed a high-fat diet (HFD). These changes are accompanied by upregulation in the jejunal-ileal expression of the Akp6 IAP isozyme (global IAP, or gIAP) and concomitant upregulation of FAT/CD36, a phosphorylated fatty acid

  12. Alkalinizing effect of NaHCO₃ with and without glucose when administered orally to euhydrated neonatal dairy calves.

    Science.gov (United States)

    Grünberg, W; Hartmann, H; Arlt, S; Burfeind, O; Staufenbiel, R

    2013-06-01

    The use of oral rehydration solutions (ORS) is well established as an effective treatment to correct water-, electrolyte-, and acid-base balance in diarrheic calves. The main ingredients of a commercial ORS are Na, glucose, and alkalinizing agents, such as NaHCO3. Particular importance is attributed to the combination of glucose and Na at a specific ratio to optimize intestinal sodium, and thereby water uptake, through the sodium-glucose co-transport. Enhancing intestinal Na absorption by combining glucose and Na in an ORS has the potential to improve the alkalinizing effect of an ORS according the strong ion theory. The objective of this study was to investigate the effect of glucose on the alkalinizing effect of NaHCO3 when administered orally. Nine healthy neonatal Holstein-Friesian calves underwent 3 oral treatments with 2-L solutions of NaHCO3 (150 mmol/L), glucose (300 mmol/L), and glucose + NaHCO3 (300 mmol/L + 150 mmol/L, respectively) in randomized order. Arterial and venous blood was obtained before treatment and in 30-min intervals thereafter for blood gas analysis and determination of plasma protein and electrolyte concentrations. Urine was collected volumetrically to determine urine volume, osmolality, pH, net acid excretion, and renal Na excretion after treatment. Plasma volume changes were extrapolated from plasma protein concentration changes. Treatment and time effects were tested with repeated measures ANOVA. Only subtle differences between oral administration of NaHCO3, with and without glucose, were observed for the change of the standard HCO3 concentration relative to baseline. No differences in plasma Na, plasma volume expansion, renal Na, net base excretion, urine volume, or pH could be identified between animals treated orally with NaHCO3 with and without glucose. Similarly, no differences in blood glucose concentration, plasma volume expansion, urine volume, or renal glucose excretion were observed in the 8h after treatment when comparing

  13. Alkaline pH homeostasis in bacteria: new insights.

    Science.gov (United States)

    Padan, Etana; Bibi, Eitan; Ito, Masahiro; Krulwich, Terry A

    2005-11-30

    The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches. Alkali-tolerance and alkaliphily, in turn, strongly depend upon mechanisms for alkaline pH homeostasis, as shown in pH shift experiments and growth experiments in chemostats at different external pH values. Transcriptome and proteome analyses have recently complemented physiological and genetic studies, revealing numerous adaptations that contribute to alkaline pH homeostasis. These include elevated levels of transporters and enzymes that promote proton capture and retention (e.g., the ATP synthase and monovalent cation/proton antiporters), metabolic changes that lead to increased acid production, and changes in the cell surface layers that contribute to cytoplasmic proton retention. Targeted studies over the past decade have followed up the long-recognized importance of monovalent cations in active pH homeostasis. These studies show the centrality of monovalent cation/proton antiporters in this process while microbial genomics provides information about the constellation of such antiporters in individual strains. A comprehensive phylogenetic analysis of both eukaryotic and prokaryotic genome databases has identified orthologs from bacteria to humans that allow better understanding of the specific functions and physiological roles of the antiporters. Detailed information about the properties of multiple antiporters in individual strains is starting to explain how specific monovalent cation/proton antiporters play dominant roles in alkaline pH homeostasis in cells that have several additional antiporters catalyzing ostensibly similar reactions. New insights into the pH-dependent Na(+)/H(+) antiporter NhaA that plays an important role in Escherichia coli have recently emerged from the determination of the

  14. Conceptual Model of Uranium in the Vadose Zone for Acidic and Alkaline Wastes Discharged at the Hanford Site Central Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-01

    Historically, uranium was disposed in waste solutions of varying waste chemistry at the Hanford Site Central Plateau. The character of how uranium was distributed in the vadose zone during disposal, how it has continued to migrate through the vadose zone, and the magnitude of potential impacts on groundwater are strongly influenced by geochemical reactions in the vadose zone. These geochemical reactions can be significantly influenced by the disposed-waste chemistry near the disposal location. This report provides conceptual models and supporting information to describe uranium fate and transport in the vadose zone for both acidic and alkaline wastes discharged at a substantial number of waste sites in the Hanford Site Central Plateau. The conceptual models include consideration of how co-disposed acidic or alkaline fluids influence uranium mobility in terms of induced dissolution/precipitation reactions and changes in uranium sorption with a focus on the conditions near the disposal site. This information, when combined with the extensive information describing uranium fate and transport at near background pH conditions, enables focused characterization to support effective fate and transport estimates for uranium in the subsurface.

  15. CHARACTERIZATION OF BULK SOIL HUMIN AND ITS ALKALINE-SOLUBLE AND ALKALINE-INSOLUBLE FRACTIONS

    Directory of Open Access Journals (Sweden)

    Cuilan Li

    2015-02-01

    Full Text Available Humic substances are the major components of soil organic matter. Among the three humic substance components (humic acid, fulvic acid, and humin, humin is the most insoluble in aqueous solution at any pH value and, in turn, the least understood. Humin has poor solubility mainly because it is tightly bonded to inorganic soil colloids. By breaking the linkage between humin and inorganic soil colloids using inorganic or organic solvents, bulk humin can be partially soluble in alkali, enabling a better understanding of the structure and properties of humin. However, the structural relationship between bulk humin and its alkaline-soluble (AS and alkaline-insoluble (AIS fractions is still unknown. In this study, we isolated bulk humin from two soils of Northeast China by exhaustive extraction (25 to 28 times with 0.1 mol L-1 NaOH + 0.1 mol L-1 Na4P2O7, followed by the traditional treatment with 10 % HF-HCl. The isolated bulk humin was then fractionated into AS-humin and AIS-humin by exhaustive extraction (12 to 15 times with 0.1 mol L-1 NaOH. Elemental analysis and solid-state 13C cross-polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR spectroscopy were used to characterize and compare the chemical structures of bulk humin and its corresponding fractions. The results showed that, regardless of soil types, bulk humin was the most aliphatic and most hydrophobic, AS-humin was the least aliphatic, and AIS-humin was the least alkylated among the three humic components. The results showed that bulk humin and its corresponding AS-humin and AIS-humin fractions are structurally differed from one another, implying that the functions of these humic components in the soil environment differed.

  16. Alkaline sorbent injection for mercury control

    Science.gov (United States)

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  17. Alkaline rocks and the occurrence of uranium

    International Nuclear Information System (INIS)

    Hambleton-Jones, B.B.; Toens, P.D.

    1980-10-01

    Many alkaline complexes contain uranium and other minerals in low concentrations and are regarded as constituting valuable potential reserves. Certain complex metallurgical problems, however, remain to be solved. Alkaline rocks occur in a number of forms and environments and it is noted that they are generated during periods of geological quiescence emplaced mainly in stable aseismic areas. Many occur along the extensions of oceanic transform faults beneath the continental crust and the application of this concept to areas not currently known to host alkaline complexes may prove useful in identifying potential target areas for prospecting operations [af

  18. Ion exchange of alkaline metals on the thin-layer zinc ferrocyanide

    International Nuclear Information System (INIS)

    Betenekov, N.D.; Buklanov, G.V.; Ipatova, E.G.; Korotkin, Yu.S.

    1991-01-01

    Basic regularities of interphase distribution in the system of thin-layer sorbent on the basis of mixed zinc ferrocyanide (FZ)-alkaline metal solution (Na, K, Rb, Cs, Fr) in the column chromatography made are studied. It is established that interphase distribution of microgram amounts of alkaline metals in the systems thin-layer FZ-NH 4 NO 3 electrolyte solutions is of ion-exchange character and subjected to of law effective mass. It is shown that FZ thin-layer material is applicable for effective chromatographic separation of alkaline metal trace amounts. An approach to the choice of a conditions of separate elution of Na, K, Rb, Cs, Fr in the column chromatography mode

  19. Geochemical features of the Cretaceous alkaline volcanics in the area of Morado hill, Jachal town, San Juan, Argentina

    International Nuclear Information System (INIS)

    Perez, L.

    2010-01-01

    This paper is about the alkaline volcanic rocks that crop out at the Morado hill located in the southern end of the Mogna ranges, which are part of the Eastern border of the pre mountain in the San Juan province, Argentina.The petrography and geochemistry study of the alkaline volcanics has allowed to classify them as tephrite basanite or basanite nephelinite, with strong alkaline chemical affinity, showing a characteristic composition of within plate geochemistry environment. The radimetric analysis, K-Ar data, has shown an average 90 ∓ 8 m.y. age for this rocks, (Cingolani et al. 1984) pointing out the Upper Cretaceous (lower section) stratigraphical position for the suite. The discussion of the results makes conspicuous the relationships of these alkaline rocks with others of the central and northwestern regions of the country that allowed to establish an alkaline petrographic province

  20. The Effect of Alkaline Concentration on Coconut Husk Crystallinity and the Yield of Sugars Released

    Science.gov (United States)

    Sangian, H. F.; Widjaja, A.

    2018-02-01

    This work was to analyze the effect of alkaline concentration on coconut coir husk crystallinity and sugar liberated enzymatically. The data showed that the employing of alkaline on lignocellulose transformed the crystallinity. The XRD peaks increased highly which indicated that cellulose was more opened and exposed. After pretreatment, the chemical compositions (cellulose, hemicellulose, and lignin) were changed significantly. The employing 1% alkaline, the cellulosic content inclined if compared to that of non-pretreatment. When the alkaline concentration was added to 4%, the cellulose was decreased slightly which indicated that a part of cellulose and hemicellulose was dissolved into solution. It was found the alkaline pretreatment influenced by the biochemical reaction of treated substrates in producing the reducing sugars. The amounts of sugar liberated enzymatically of coconut husk treated by 1% and 4% alkaline increased to 0.26, and 0.24 g sugar/g (cellulose+hemicellulose), respectively, compared to that of native solid recorded at 0.18 g sugar/g (cellulose+hemicellulose).

  1. Alkalinity in oil field waters - what alkalinity is and how it is measured

    International Nuclear Information System (INIS)

    Kaasa, B.; Oestvold, T.

    1996-01-01

    The alkalinity is an important parameter in the description of pH-behaviour, buffer capacity and scaling potentials in oil field waters. Although the alkalinity is widely used, it seems to be considerable confusion in connection with the concept. It is often used incorrectly and different authors define the concept in different ways. Several different methods for the determination of alkalinity can be found in the literature. This paper discusses the definition of alkalinity and how to use alkalinity in oil field waters to obtain data of importance for scale and pH predictions. There is also shown how a simple titration of oil field waters can give both the alkalinity and the content of organic acids in these waters. It is obvious from these findings that most of the methods used to day may give considerable errors when applied to oil field waters with high contents of organic acids. 8 refs., 8 figs., 5 tabs

  2. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D

    1999-01-01

    .... With energy density in excess of 300 mJ/cc and the potential to exceed a power density of 100 W/cc, the alkaline electrochemical capacitor represents a significant advancement in technology for high power energy storage.

  3. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 3. Qualitative Carbohydrate Analysis using Alkaline Potassium Ferricyanide. Sangeeta Pandita Saral Baweja. Classroom Volume 21 Issue 3 March 2016 pp 285-288 ...

  4. Deciphering the protective role of spermidine against saline-alkaline stress at physiological and proteomic levels in tomato.

    Science.gov (United States)

    Zhang, Yi; Zhang, Hao; Zou, Zhi-Rong; Liu, Yi; Hu, Xiao-Hui

    2015-02-01

    In this research, the protective effect of spermidine (Spd) in mitigating saline-alkaline stress in tomato (Solanum lycopersicum L.) at physiological and proteomic levels were examined. The results showed that saline-alkaline stress induced accumulation of H2O2 and O2(-*), and increased the activities of antioxidase (SOD, CAT, and POD). Spermidine efficiently alleviated the inhibitory role of saline-alkaline on plant growth and inhibited saline-alkaline stress-induced H2O2 and O2(-*) accumulation. Proteomics investigations of the leaves of tomato seedlings, responding to a 75 mM saline-alkaline solution and 0.25 mM Spd, were performed. Maps of the proteome of leaf extracts were obtained by two-dimensional gel electrophoresis. An average of 49, 47 and 34 spots, which appeared repeatedly and that significantly altered the relative amounts of polypeptides by more than twofold, were detected for seedlings treated with saline-alkaline solution (S) compared to normal solution (CK), saline-alkaline plus spermidine (MS) compared to CK, or S versus MS, respectively. Thirty-nine of these proteins were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and were classified into five functional categories, including energy and metabolism, signal transduction, amino acid metabolism, protein metabolism, and stress-defense response. Proteomics analysis coupled with bioinformatics indicated that Spd treatment helps tomato seedlings combat saline-alkaline stress by modulating the defense mechanism of plants and activating cellular detoxification, which protect plants from oxidative damage induced by saline-alkaline stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Hybrid Alkaline Cements: Bentonite-Opc Binders

    Directory of Open Access Journals (Sweden)

    Ines Garcia-Lodeiro

    2018-03-01

    Full Text Available Moderately alkaline activators can be used to formulate cementitious binders with a high Supplemetary Cementitious Materials (SCMs and a low portland cement content (hybrid alkaline cements. This study aimed to prepare hybrid alkaline cements containing large percentages of dehydroxylated bentonite (BT and small Portland cement (OPC fractions, with 5% Na2SO4 as a solid alkaline activator. The hydration kinetics of the pastes hydrated in water in the presence and absence of the solid activator were assessed by isothermal conduction calorimetry, whilst the reaction products were characterised with X-Ray Powder Diffraction (XRD and Fourier-transform Infrared Spectroscopy (FTIR. The presence of the alkaline activator hastened OPC and BT/OPC hydration: more heat of hydration was released, favouring greater initial bentonite reactivity. The portlandite forming during cement hydration reacted readily with the Na2SO4, raising medium alkalinity and enhancing bentonite dissolution and with it reaction product precipitation (primarily (N,C-A-S-H-like gels that co-exist with C-S-H- or C-A-S-H-like gels. The presence of sulfate ions favoured the formation of AFm-like phases. Preceding aspects accelerated the hydration reactions, with the formation of more reaction product and matrix densification. As a result, the 28 days Na2SO4 activated systems developed greater mechanical strength than the water-hydrated systems, with the 60% BT/40% OPC blends exhibiting higher compressive strength than the 100% OPC pastes.

  6. Actinide-aluminate Speciation in Alkaline Radioactive Waste

    International Nuclear Information System (INIS)

    Clark, David C.; Krot, Nikolai N.

    2000-01-01

    Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am-the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting their solubility and sorption behavior in tanks, determining whether chemical separations are needed for waste treatment, and designing separations processes. Baseline washing of tank sludges with NaOH solutions is being proposed to reduce the volume of HLW. Alkaline pretreatment of HLW will be needed to remove aluminum [as NaAl(OH)4] because it significantly reduces the HLW volume; however, the aluminate ion [Al(OH)4 -] enhances actinide solubility via an unknown mechanism. Thus, alkaline wash residues may require an additional treatment to remove actinides. The results of this research will determine the nature TRU (U, Np, Pu, Am) speciation with aluminate anions under alkaline, oxidizing tank-like conditions. Specific issues to be addressed include solubility of these actinides, speciation in aluminate-containing alkaline supernatants, the role of actinide redox states on solubility, and partitioning between supernatant and solid phases, including colloids. Studies will include thermodynamics, kinetics, spectroscopy, electrochemistry, and surface science. We have already determined, for example, that certain high valent forms of Np and Pu are very soluble under alkaline conditions due to the formation of anionic hydroxo complexes, AnO2(OH)4 2- and AnO2(OH)5 3-. The presence of aluminate ions causes the actinide solubilities to increase, although the exact species are not known. We are currently characterizing the high valent TRU elements bound to oxo, water, OH-, and Al(OH)4 -, ligands under waste-like conditions. These waste-like conditions are in the range of 1-3 M excess hydroxide, ∼0.2 M carbonate, ∼0.5 M aluminate, for a total sodium of 2-4 M. Molecular structure-specific probes

  7. The Effect of Alkaline Activator Ratio on the Compressive Strength of Fly Ash-Based Geopolymer Paste

    Science.gov (United States)

    Lăzărescu, A. V.; Szilagyi, H.; Baeră, C.; Ioani, A.

    2017-06-01

    Alkaline activation of fly ash is a particular procedure in which ash resulting from a power plant combined with a specific alkaline activator creates a solid material when dried at a certain temperature. In order to obtain desirable compressive strengths, the mix design of fly ash based geopolymer pastes should be explored comprehensively. To determine the preliminary compressive strength for fly ash based geopolymer paste using Romanian material source, various ratios of Na2SiO3 solution/ NaOH solution were produced, keeping the fly ash/alkaline activator ratio constant. All the mixes were then cured at 70 °C for 24 hours and tested at 2 and 7 days, respectively. The aim of this paper is to present the preliminary compressive strength results for producing fly ash based geopolymer paste using Romanian material sources, the effect of alkaline activators ratio on the compressive strength and studying the directions for future research.

  8. Ammonium carbonate and/or bicarbonate plus alkaline chlorate oxidant for recovery of uranium values

    International Nuclear Information System (INIS)

    Stapp, P.R.

    1983-01-01

    In accordance with the present invention, uranium values are extracted from materials containing uranium in valence states lower than its hexavalent state by contacting the materials containing uranium with an aqueous alkaline leach solution containing an alkaline chlorate in an amount sufficient to oxidize at least a portion of the uranium in valence states lower than its hexavalent state to its hexavalent state. In a further embodiment of the present invention, the alkaline leach solution is an aqueous solution of a carbonate selected from the group consisting of ammonium carbonate, ammonium bicarbonate and mixtures thereof. In yet another embodiment of the present invention, at least one catalytic compound of a metal selected from the group consisting of copper, cobalt, iron, nickel, chromium and mixtures thereof adapted to assure the presence of the ionic species Cu ++ , Co ++ , Fe +++ , Ni ++ , Cr +++ and mixtures thereof, respectively, during the contacting of the material containing uranium with the alkaline leach solution and in an amount sufficient to catalyze the oxidation of at least a portion of the uranium in its lower valence states to its hexavalent state, is present

  9. Alkaline leaching for synthesis of improved Fe-ZSM5 catalysts

    NARCIS (Netherlands)

    Espinosa, S; Mentruit, C; Kapteijn, F; Moulijn, JA; Melián-Cabrera, I.

    Fe-ZSM5 catalysts were fully Fe-exchanged by pretreating the parent zeolite with base a solution prior to the Fe-exchange. The catalysts prepared in this way showed very low amount of inactive FeOx and improved performance in N2O decomposition. Alkaline leaching breaks down the zeolite crystals -

  10. Behavior of ellagitannins, gallic acid, and ellagic acid under alkaline conditions

    Science.gov (United States)

    Richard W. Hemingway; W.E. Hillis

    1971-01-01

    Examination of the rates of hydrolysis of different ellagitannins under conditions comparable with cold soda and alkaline-groundwood pulping processes showed that some ellagitannins are notably resistant to hydrolysis. The rate of hydrolysis was dependent upon the pH and tempemture of the solution and particularly upon the structure of the compound. Decarboxylation of...

  11. Dietary free fatty acids form alkaline phosphatase-enriched microdomains in the intestinal brush border membrane

    DEFF Research Database (Denmark)

    Hansen, Gert H; Rasmussen, Karina; Niels-Christiansen, Lise-Lotte

    2011-01-01

    mimicking a physiological solution of dietary mixed micelles, rearranged the lipid raft microdomain organization of the membranes. Thus, the fat mixture generated a low-density subpopulation of microvillar detergent resistant membranes (DRMs) highly enriched in alkaline phosphatase (AP). Since this GPI...

  12. Electrocatalysis of the HER in acid and alkaline media

    Directory of Open Access Journals (Sweden)

    Danilovic Nemanja

    2013-01-01

    Full Text Available Trends in the HER are studied on selected metals (M= Cu, Ag, Au, Pt, Ru, Ir, Ti in acid and alkaline environments. We found that with the exception of Pt, Ir and Au, due to high coverage by spectator species on non-noble metal catalysts, experimentally established positions of Cu , Ag, Ru and Ti in the observed volcano relations are still uncertain. We also found that while in acidic solutions the M-Hupd binding energy most likely is controlling the activity trends, the trends in activity in alkaline solutions are controlled by a delicate balance between two descriptors: the M-Had interaction as well as the energetics required to dissociate water molecules. The importance of the second descriptor is confirmed by introducing bifunctional catalysts such as M modified by Ni(OH; e.g. while the latter serves to enhance catalytic decomposition of water, the metal sites are required for collecting and recombining the produced hydrogen intermediates.

  13. Study of the alkaline fading of phenolphthalein in microemulsions.

    Science.gov (United States)

    Mao, Shiyan; Chen, Zhiyun; An, Xueqin; Shen, Weiguo

    2011-06-09

    The reactions of the alkaline fading of phenolphthalein (PN) have been studied in water/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane microemulsions by monitoring the absorbance changes of PN in the system with the time and the results compared with those found for the same reactions in aqueous solutions. It was found that the values of the equilibrium constants and the forward reaction rate constants in the microemulsions were significantly larger than that in aqueous solutions and decreased with increasing the molar ratio of water to AOT (ω), except for that with low ω. The temperature dependence of the reaction rate constant was analyzed to obtain the values of free energy, enthalpy, and entropy of activation, which suggests the existence of an isokinetic relationship and a common mechanism for the reactions occurring in the microemulsions with different ω. It was also observed that the competition between the reactions of the alkaline fading of PN and the hydrolyzation of AOT in water/AOT/isooctane microemulsions when the reaction time was sufficiently long.

  14. 21 CFR 864.7660 - Leukocyte alkaline phosphatase test.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Leukocyte alkaline phosphatase test. 864.7660... Leukocyte alkaline phosphatase test. (a) Identification. A leukocyte alkaline phosphatase test is a device used to identify the enzyme leukocyte alkaline phosphatase in neutrophilic granulocytes (granular...

  15. Improved electrodes and gas impurity investigations on alkaline electrolysers

    DEFF Research Database (Denmark)

    Reissner, R.; Schiller, G.; Knoeri, T.

    Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved.......Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved....

  16. Cellulose Degradation at Alkaline Conditions: Long-Term Experiments at Elevated Temperatures

    International Nuclear Information System (INIS)

    Glaus, M.A.; Van Loon, L.R.

    2004-04-01

    temperatures tested here. It may be hypothesised that the alkaline hydrolysis has even not been observed in the experiments. However, if this is true, cellulose degradation proceeded via another unknown type of reaction. Mass balances for carbon show that the large majority of reaction products found in solution can be explained by formation of isosaccharinic acids and other low-molecular weight carboxylic acids. With respect to long-term predictions for cellulose degradation at room temperature it can be concluded that the kinetic parameters for alkaline hydrolysis as proposed in the work of PAVASARS (Linkoping Studies in Arts and Science, 196, Linkoping University, Sweden, 1999) are too large and that complete cellulose degradation at these temperatures occurs only within time scales larger than hundreds of years. However, it is not possible from the experimental evidences, to corroborate the validity of a linear extrapolation (Arrhenius equation) of the reaction rates measured at temperatures between 140 and 190 o C to room temperature, from which it was previously concluded that complete cellulose degradation would take time spans of the order of millions of years. An interesting observation in the present experiments is the chemical instability of aisosaccharinic acid at 90 o C, which has been hypothetically interpreted as a fragmentation induced by the sorption of α-isosaccharinic acid on Ca(OH) 2 . Carbon mass balances show that α-isosaccharinic acid is thereby transformed to other lowmolecular weight carboxylic acids. Such a reaction would be an interesting long-term perspective for performance assessment of the disposal of cellulose-containing radioactive waste, in that it may reduce the concentration of organic compounds strongly complexing radionuclides. (author)

  17. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  18. Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.

    2014-01-01

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  19. Measurement of pH, alkalinity and acidity in ultra-soft waters

    African Journals Online (AJOL)

    drinie

    2001-10-04

    Oct 4, 2001 ... A blend composed of the raw water, sodium chloride (to increase conductivity), and standard bicarbonate (to increase buffering capacity) was titrated with standard strong acid in two pH regions: 6.3 pH < 4.0. In both methods, total alkalinity was determined using the latter set of points, ...

  20. Silica-poor, mafic alkaline lavas from ocean islands and continents

    Indian Academy of Sciences (India)

    Strongly silica-poor (ne-normative), mafic alkaline lavas generally represented by olivine nephelinites, nephelinites, melilitites, and olivine melilitites have erupted at various locations during Earth's history. On the basis of bulk-rock Mg#, high concentrations of Na2O, TiO2, and K2O, and trace element geochemistry, it has ...

  1. Solution of the Neutron transport equation in hexagonal geometry using strongly discontinuous nodal schemes; Solucion de la Ecuacion de transporte de neutrones en geometria hexagonal usando esquemas nodales fuertemente discontinuos

    Energy Technology Data Exchange (ETDEWEB)

    Mugica R, C.A.; Valle G, E. del [IPN, ESFM, Departamento de Ingenieria Nuclear, 07738 Mexico D.F. (Mexico)]. e-mail: cmugica@ipn.mx

    2005-07-01

    In 2002, E. del Valle and Ernest H. Mund developed a technique to solve numerically the Neutron transport equations in discrete ordinates and hexagonal geometry using two nodal schemes type finite element weakly discontinuous denominated WD{sub 5,3} and WD{sub 12,8} (of their initials in english Weakly Discontinuous). The technique consists on representing each hexagon in the union of three rhombuses each one of which it is transformed in a square in the one that the methods WD{sub 5,3} and WD{sub 12,8} were applied. In this work they are solved the mentioned equations of transport using the same discretization technique by hexagon but using two nodal schemes type finite element strongly discontinuous denominated SD{sub 3} and SD{sub 8} (of their initials in english Strongly Discontinuous). The application in each case as well as a reference problem for those that results are provided for the effective multiplication factor is described. It is carried out a comparison with the obtained results by del Valle and Mund for different discretization meshes so much angular as spatial. (Author)

  2. Alkaline treatment on piassava (Attalea funifera martius) fiber

    International Nuclear Information System (INIS)

    Santos, E.B.C.; Moreno, C.G.; Barros, J.J.P.; Moura, D.A.; Fim, F.C.; Wellen, R.M.R.; Silva, L.B.

    2016-01-01

    Alkaline treatment on piassava fiber with size inferior to 270 mesh was performed to remove impurities. The treatments took place under magnetic stirring and Sodium Hydroxide (NaOH) solution with 2, 4, 6 and 8% of concentration; processing time ranged between 100 and 400 minutes, with intervals of 25 minutes; the main object was to reach the optimum concentration and time. The concentration 2% was used to remove efficiently the impurities without damaging excessively the fiber. The fibers were characterized by means of X-ray diffraction (XRD) and optical microscopy (OM). Fibers presented XRD diffraction peak around 22 deg, due to the crystalline structure of cellulose. By optical microscopy was observed the treatment efficacy of the 2% NaOH solution in removing surface impurities. (author)

  3. Long-term trends in alkalinity in large rivers of the conterminous US in relation to acidification, agriculture, and hydrologic modification.

    Science.gov (United States)

    Stets, E G; Kelly, V J; Crawford, C G

    2014-08-01

    Alkalinity increases in large rivers of the conterminous US are well known, but less is understood about the processes leading to these trends as compared with headwater systems more intensively examined in conjunction with acid deposition studies. Nevertheless, large rivers are important conduits of inorganic carbon and other solutes to coastal areas and may have substantial influence on coastal calcium carbonate saturation dynamics. We examined long-term (mid-20th to early 21st century) trends in alkalinity and other weathering products in 23 rivers of the conterminous US. We used a rigorous flow-weighting technique which allowed greater focus on solute trends occurring independently of changes in flow. Increasing alkalinity concentrations and yield were widespread, occurring at 14 and 13 stations, respectively. Analysis of trends in other weathering products suggested that the causes of alkalinity trends were diverse, but at many stations alkalinity increases coincided with decreasing nitrate+sulfate and decreasing cation:alkalinity ratios, which is consistent with recovery from acidification. A positive correlation between the Sen-Thiel slopes of alkalinity increases and agricultural lime usage indicated that agricultural lime contributed to increasing solute concentration in some areas. However, several stations including the Altamaha, Upper Mississippi, and San Joaquin Rivers exhibited solute trends, such as increasing cation:alkalinity ratios and increasing nitrate+sulfate, more consistent with increasing acidity, emphasizing that multiple processes affect alkalinity trends in large rivers. This study was unique in its examination of alkalinity trends in large rivers covering a wide range of climate and land use types, but more detailed analyses will help to better elucidate temporal changes to river solutes and especially the effects they may have on coastal calcium carbonate saturation state. Published by Elsevier B.V.

  4. Ion exchange pretreatment of alkaline radwaste for cesium removal

    International Nuclear Information System (INIS)

    Bibler, J.P.

    1994-08-01

    A cation exchange resin has been tested for its ability to remove the Cs ion from simulants of highly alkaline liquid nuclear wastes found at the Savannah River Site, Oak Ridge, and Hanford. The resin is a condensation polymer of the K salt of resorcinol and formaldehyde. It removes milli- and micromolar amounts of Cs + from solutions that contain as high as 11 molar Na + . Small column tests indicate that approximately 200 column volumes of SRS simulant and 205 column volumes of OR Tank 25 supernatant simulant can be processed before the resin requires regeneration. For these two wastes, a carousel arrangement of two columns in series and a third in reserve can be used effectively in a process. Hanford 101-AW simulant generates a less sharp breakthrough profile with this resin, though an operation using a maximum of three columns in series with another column off-line for regeneration would be effective if the resin beds are allowed to reach about 90% breakthrough before taking them out of service. Parameters that effect the performance of the resin with a particular feed solution are the concentrations of the two primary ions of interest, Cs + and Na + , as well as the concentrations of K + and OH - . A further ramification of the hydroxide ion concentration is its role in assisting oxidation of the resin, thereby destroying its usefulness in cesium removal. Although the performance of the resin is unaffected at doses of 1 E+8 rad ionizing radiation, it shows noticeable degradation after storage for 100 hours in alkaline solutions, generating quinone and ketone groups, as determined from C-13 NMR and by an increase in total organic C content of the contacting solution. Gases detected from the radiolysis of the resin/simulant mixture are CO 2 from the resin, N 2 O from nitrate in the simulant, and H 2 possibly from resin and simulant. Oxygen depletion in the mixture results from radiolysis and chemical degradation

  5. Effect of Stress Ratio and Loading Frequency on the Corrosion Fatigue Behavior of Smooth Steel Wire in Different Solutions

    Directory of Open Access Journals (Sweden)

    Songquan Wang

    2016-09-01

    Full Text Available In this work, the effects of loading condition and corrosion solution on the corrosion fatigue behavior of smooth steel wire were discussed. The results of polarization curves and weight loss curves showed that the corrosion of steel wire in acid solution was more severe than that in neutral and alkaline solutions. With the extension of immersion time in acid solution, the cathodic reaction of steel wire gradually changed from the reduction of hydrogen ion to the reduction of oxygen, but was always the reduction of hydrogen ion in neutral and alkaline solutions. The corrosion kinetic parameters and equivalent circuits of steel wires were also obtained by simulating the Nyquist diagrams. In corrosion fatigue test, the effect of stress ratio and loading frequency on the crack initiation mechanism was emphasized. The strong corrosivity of acid solution could accelerate the nucleation of crack tip. The initiation mechanism of crack under different conditions was summarized according to the side and fracture surface morphologies. For the crack initiation mechanism of anodic dissolution, the stronger the corrosivity of solution was, the more easily the fatigue crack source formed, while, for the crack initiation mechanism of deformation activation, the lower stress ratio and higher frequency would accelerate the generation of corrosion fatigue crack source.

  6. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  7. Prophylactic treatment with alkaline phosphatase in cardiac surgery induces endogenous alkaline phosphatase release

    NARCIS (Netherlands)

    Kats, Suzanne; Brands, Ruud; Hamad, Mohamed A. Soliman; Seinen, Willem; Schamhorst, Volkher; Wulkan, Raymond W.; Schoenberger, Jacques P.; van Oeveren, Wim

    Introduction: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels

  8. Radiolytic synthesis and characterization of PVA and chitosan based conductive polymer membranes for alkaline fuel cells

    Directory of Open Access Journals (Sweden)

    Stoševski Ivan D.

    2014-01-01

    Full Text Available Poly(vinyl alcohol (PVA and chitosan (CS based polymer membranes for alkaline fuel cells were synthesized by gamma irradiation method. They were swollen with 6 M KOH solution and their ionic conductivity and gas permeance were investigated as a function of temperature. They show high ionic conductivities at room temperature, which wasn't reduced over a period of few months. No gas flow through membranes was detected at any temperature and pressure. These properties show that the membranes could be potentially applied in alkaline fuel cells.

  9. The stability of polyaniline in strongly alkaline and acidic aqueous media

    Czech Academy of Sciences Publication Activity Database

    Brožová, Libuše; Holler, Petr; Kovářová, Jana; Stejskal, Jaroslav; Trchová, Miroslava

    2008-01-01

    Roč. 93, č. 3 (2008), s. 592-600 ISSN 0141-3910 R&D Projects: GA MPO FT-TA2/098; GA ČR GA203/08/0686 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * stability * conducting polymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.320, year: 2008

  10. Carbon dioxide mediates duodenal mucosal alkaline secretion in response to luminal acidity in the anesthetized rat.

    Science.gov (United States)

    Holm, M; Johansson, B; Pettersson, A; Fändriks, L

    1998-09-01

    Acid exposure of the duodenum elicits various functional responses, e.g., an increased mucosal alkaline secretion. Despite low pH in luminal contents, the mucosal secretion of bicarbonate-rich fluid results in pH neutrality at the surface epithelium. It follows that it is probably not luminal pH that triggers the secretory response. The present study was undertaken to investigate if CO2 could serve as an intermediate messenger between luminal acid and the mucosal secretory response. Experiments were performed on chloralose-anesthetized rats. The duodenal mucosal alkaline secretion was measured by in situ pH-stat titration. Exposure of the duodenal mucosa to CO2, administered either as a pregassed solution (pH 4, PCO2 700 mm Hg) or as an acidified bicarbonate solution (pH 6.4, PCO2 240 mm Hg), raised the alkaline output by approximately 65%. This response was blocked by the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (0.3 mmol/L intraluminally) but not by indomethacin (5 mg/kg intravenously). Exposure of the duodenal mucosa to solutions with high concentrations of CO2 increases the mucosal alkaline secretion despite an almost neutral pH. Data indicate that the L-arginine/NO pathway is involved in the mediation of this response.

  11. Investigation on application of homogeneous and heterogeneous catalysis for alkaline waste treatment

    International Nuclear Information System (INIS)

    Shilov, V.P.; Bessonov, A.A.; Garnov, A.Y.; Gelis, A.V.

    1997-09-01

    The stabilization of neptunium(IV) in alkaline solution by chemical reductants under various conditions was studied. Testing showed that neptunium(V) is slowly reduced to Np(IV) by V(IV) at room temperature in alkaline solutions. Increasing temperature accelerates reduction. Complete reduction of 2 x 10 -4 M Np(V) occurs in three hours at 80 degrees C in 1 M NaOH with 0.02 M VOSO 4- . Under similar conditions, but in 5 M NaOH, only 15 to 20% of the Np(V) was reduced in 5 hours. In all cases, about 98 % of the initial neptunium was found in the precipitate. Thus V(IV) acts both as a reductant and as a precipitation carrier. Tests showed Np(V) reduction by hydrazine hydrate could be catalyzed by Pd(II). Reduction increased with temperature and catalyst concentration and decreased with hydroxide concentration. Reduction of Np(V) also takes place in 1 M NaOH solutions containing 1 M sodium formate and palladium. Increasing temperature accelerates reduction; with three hours' treatment in 5 M NaOH solution at 90 degrees C, about 95 % of the initial 2 x 10 -4 M neptunium(V) is transformed to Np(IV). Organic complexants and organic acid anions hinder the decontamination of alkaline solutions from neptunium and plutonium by coprecipitation with d-element hydroxides (the Method of Appearing Reagents). It was found that ethylenediaminetetraacetate (EDTA) and N-(2-hydroxyethyl) ethylenediaminetriacetate (HEDTA) are decomposed by H 2 O 2 in alkaline solution in the presence of cobalt compounds with heating and by Na2S208 at moderate temperatures. Citrate, glycolate, and oxalate are decomposed by Na 2 S 2 O 8 with heating. Oxidant amounts must be increased when NaNO 2 also is present in solution. 8 refs., 25 figs., 16 tabs

  12. Understanding of alkaline pretreatment parameters for corn stover enzymatic saccharification

    Directory of Open Access Journals (Sweden)

    Chen Ye

    2013-01-01

    Full Text Available Abstract Background Previous research on alkaline pretreatment has mainly focused on optimization of the process parameters to improve substrate digestibility. To achieve satisfactory sugar yield, extremely high chemical loading and enzyme dosages were typically used. Relatively little attention has been paid to reduction of chemical consumption and process waste management, which has proven to be an indispensable component of the bio-refineries. To indicate alkali strength, both alkali concentration in pretreatment solution (g alkali/g pretreatment liquor or g alkali/L pretreatment liquor and alkali loading based on biomass solids (g alkali/g dry biomass have been widely used. The dual approaches make it difficult to compare the chemical consumption in different process scenarios while evaluating the cost effectiveness of this pretreatment technology. The current work addresses these issues through pretreatment of corn stover at various combinations of pretreatment conditions. Enzymatic hydrolysis with different enzyme blends was subsequently performed to identify the effects of pretreatment parameters on substrate digestibility as well as process operational and capital costs. Results The results showed that sodium hydroxide loading is the most dominant variable for enzymatic digestibility. To reach 70% glucan conversion while avoiding extensive degradation of hemicellulose, approximately 0.08 g NaOH/g corn stover was required. It was also concluded that alkali loading based on total solids (g NaOH/g dry biomass governs the pretreatment efficiency. Supplementing cellulase with accessory enzymes such as α-arabinofuranosidase and β-xylosidase significantly improved the conversion of the hemicellulose by 6–17%. Conclusions The current work presents the impact of alkaline pretreatment parameters on the enzymatic hydrolysis of corn stover as well as the process operational and capital investment costs. The high chemical consumption for alkaline

  13. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  14. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  15. De Novo Transcriptional Analysis of Alfalfa in Response to Saline-Alkaline Stress.

    Science.gov (United States)

    An, Yi-Min; Song, Li-Li; Liu, Ying-Rui; Shu, Yong-Jun; Guo, Chang-Hong

    2016-01-01

    Saline-alkaline stress, caused by high levels of harmful carbonate salts and high soil pH, is a major abiotic stress that affects crop productivity. Alfalfa is a widely cultivated perennial forage legume with some tolerance to biotic and abiotic stresses, especially to saline-alkaline stress. To elucidate the mechanism underlying plant saline-alkaline tolerance, we conducted transcriptome analysis of whole alfalfa seedlings treated with saline-alkaline solutions for 0 day (control), 1 day (short-term treatment), and 7 days (long-term treatment) using ion torrent sequencing technology. A transcriptome database dataset of 53,853 unigenes was generated, and 2,286 and 2,233 genes were differentially expressed in the short-term and long-term treatment, respectively. Gene ontology analysis revealed 14 highly enriched pathways and demonstrated the differential response of metabolic pathways between the short-term and long-term treatment. The expression levels of 109 and 96 transcription factors were significantly altered significantly after 1 day and 7 days of treatment, respectively. Specific responses of peroxidase, flavonoids, and the light pathway component indicated that the antioxidant capacity was one of the central mechanisms of saline-alkaline stress tolerance response in alfalfa. Among the 18 differentially expressed genes examined by real time PCR, the expression levels of eight genes, including inositol transporter, DNA binding protein, raffinose synthase, ferritin, aldo/keto reductase, glutathione S-transferase, xyloglucan endotrans glucosylase, and a NAC transcription factor, exhibited different patterns in response to saline and alkaline stress. The expression levels of the NAC transcription factor and glutathione S-transferase were altered significantly under saline stress and saline-alkaline stress; they were upregulated under saline-alkaline stress and downregulated under salt stress. Physiology assays showed an increased concentration of reactive oxygen

  16. A simple route to synthesize conductive stimuli-responsive polypyrrole nanocomposite hydrogel particles with strong magnetic properties and their performance for removal of hexavalent chromium ions from aqueous solution

    Science.gov (United States)

    Ahmad, Hasan; Rahman, Mohammad Mostafizar; Ali, Mohammad Azgar; Minami, Hideto; Tauer, Klaus; Gafur, Mohammad Abdul; Rahman, Mohammad Mahbubor

    2016-08-01

    A combination of maghemite polypyrrole (PPy/γ-Fe2O3) and stimuli-responsive properties in the same hydrogel microspheres is expected to enhance their application potential in various fields such as tissue engineering, regenerative medicine, biosensors, biomedical applications and removal of heavy metals from waste water, catalysis etc. In this investigation a simple two step process is used to prepare conductive stimuli-responsive polypyrrole (PPy) composite hydrogel particles with strong magnetic properties. Poly(styrene-methacrylic acid-N-isopropylacrylamide-polyethelene glycol methacrylate) or P(S-NIPAM-MAA-PEGMA) hydrogel seed particles are first prepared by soap-free precipitation copolymerization. The copolymer hydrogel particles exhibited both temperature- and pH-responsive volume phase transition. Conductive P(S-NIPAM-MAA-PEGMA)/PPy/γ-Fe2O3 nanocomposite hydrogel particles are then prepared by seeded chemical oxidative polymerization of pyrrole in the presence of P(S-NIPAM-MAA-PEGMA) hydrogel seed particles using FeCl3 as a oxidant and p-toluene sulfonic acid (p-TSA) as a dopant. In the reaction system FeCl3 functioned as a source of Fe(III) for the formation of γ-Fe2O3. This reaction also requires the initial presence of Fe(II) provided by the addition of FeCl2. The size and size distribution, surface structure, and morphology of the prepared conductive composite hydrogel particles are confirmed by FTIR, electron micrographs, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV-visible spectroscopy. The performance of nanocomposite hydrogel particles has been evaluated for the removal of hexavalent chromium (Cr) ions from water.

  17. Assessing ocean alkalinity for carbon sequestration

    Science.gov (United States)

    Renforth, Phil; Henderson, Gideon

    2017-09-01

    Over the coming century humanity may need to find reservoirs to store several trillions of tons of carbon dioxide (CO2) emitted from fossil fuel combustion, which would otherwise cause dangerous climate change if it were left in the atmosphere. Carbon storage in the ocean as bicarbonate ions (by increasing ocean alkalinity) has received very little attention. Yet recent work suggests sufficient capacity to sequester copious quantities of CO2. It may be possible to sequester hundreds of billions to trillions of tons of C without surpassing postindustrial average carbonate saturation states in the surface ocean. When globally distributed, the impact of elevated alkalinity is potentially small and may help ameliorate the effects of ocean acidification. However, the local impact around addition sites may be more acute but is specific to the mineral and technology. The alkalinity of the ocean increases naturally because of rock weathering in which >1.5 mol of carbon are removed from the atmosphere for every mole of magnesium or calcium dissolved from silicate minerals (e.g., wollastonite, olivine, and anorthite) and 0.5 mol for carbonate minerals (e.g., calcite and dolomite). These processes are responsible for naturally sequestering 0.5 billion tons of CO2 per year. Alkalinity is reduced in the ocean through carbonate mineral precipitation, which is almost exclusively formed from biological activity. Most of the previous work on the biological response to changes in carbonate chemistry have focused on acidifying conditions. More research is required to understand carbonate precipitation at elevated alkalinity to constrain the longevity of carbon storage. A range of technologies have been proposed to increase ocean alkalinity (accelerated weathering of limestone, enhanced weathering, electrochemical promoted weathering, and ocean liming), the cost of which may be comparable to alternative carbon sequestration proposals (e.g., $20-100 tCO2-1). There are still many

  18. Long-term and seasonal variations in CO 2 : linkages to catchment alkalinity generation

    Science.gov (United States)

    Norton, Stephen A.; Cosby, Bernard J.; Fernandez, Ivan J.; Kahl, Jeffrey S.; Robbins Church, M.

    As atmospheric emissions of S have declined in the Northern Hemisphere, there has been an expectation of increased pH and alkalinity in streams believed to have been acidified by excess S and N. Many streams and lakes have not recovered. Evidence from East Bear Brook in Maine, USA and modelling with the groundwater acid-base model MAGIC (Cosby et al. 1985a,b) indicate that seasonal and yearly variations in soil PCO2 are adequate to enhance or even reverse acid-base (alkalinity) changes anticipated from modest decreases of SO4 in surface waters. Alkalinity is generated in the soil by exchange of H+ from dissociation of H2CO3, which in turn is derived from the dissolving of soil CO2. The variation in soil PCO2 produces an alkalinity variation of up to 15 meq L-1 in stream water. Detecting and relating increases in alkalinity to decreases in stream SO4 are significantly more difficult in the short term because of this effect. For example, modelled alkalinity recovery at Bear Brook due to a decline of 20 meq SO4 L-1 in soil solution is compensated by a decline from 0.4 to 0.2% for soil air PCO2. This compensation ability decays over time as base saturation declines. Variable PCO2 has less effect in more acidic soils. Short-term decreases of PCO2 below the long-term average value produce short-term decreases in alkalinity, whereas short-term increases in PCO2 produce short-term alkalization. Trend analysis for detecting recovery of streams and lakes from acidification after reduced atmospheric emissions will require a longer monitoring period for statistical significance than previously appreciated.

  19. Catalytic oxidation of soot over alkaline niobates

    International Nuclear Information System (INIS)

    Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.

    2013-01-01

    Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

  20. Separation of pig bone alkaline phosphatase activities.

    Science.gov (United States)

    Leunis, J C; Vancraeynest, T; Brauman, J

    1977-01-01

    A simple method for the separation of alkaline phosphatase and pyrophosphatase activities of pig bone ribs is described. Using anionic exchange chromatography (DEAE-cellulose) and affinity chromatography on Concanavalin A sepharose (Con A) eluted by a step pH gradient and Na4P2O7, several activities were obtained. A pyrophosphatase containing very little alkaline phosphatase activity was isolated from Con A sepharose by elution with pyrophosphatase. Our data are consistent, with the hypothesis that cortical alcaline phosphatase and pyrophosphatase activities are not due to a single enzyme protein. The method was used on whole bone, on bone marrow and on cortical bone.

  1. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    Science.gov (United States)

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  2. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Science.gov (United States)

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

    2014-01-01

    The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

  3. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Directory of Open Access Journals (Sweden)

    Eero eSalminen

    2014-02-01

    Full Text Available The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat benzalkonium [ADBA] (alkyldimethylbenzylammonium was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs. Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC. The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  4. Characterization Of Actinides In Simulated Alkaline Tank Waste Sludges And Leachates

    International Nuclear Information System (INIS)

    Nash, Kenneth L.

    2008-01-01

    In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.

  5. CHARACTERIZATION OF ACTINIDES IN SIMULATED ALKALINE TANK WASTE SLUDGES AND LEACHATES

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Kenneth L.

    2008-11-20

    In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.

  6. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  7. MudPIT analysis of alkaline tolerance by Listeria monocytogenes strains recovered as persistent food factory contaminants.

    Science.gov (United States)

    Nilsson, Rolf E; Latham, Roger; Mellefont, Lyndal; Ross, Tom; Bowman, John P

    2012-05-01

    Alkaline solutions are used to clean food production environments but the role of alkaline resistance in persistent food factory contamination by Listeria monocytogenes is unknown. We used shotgun proteomics to characterise alkaline adapted L. monocytogenes recovered as persistent and transient food factory contaminants. Three unrelated strains were studied including two persistent and a transient food factory contaminant determined using multilocus sequence typing (MLST). The strains were adapted to growth at pH 8.5 and harvested in exponential phase. Protein extracts were analysed using multidimensional protein identification technology (MudPIT) and protein abundance compared by spectra counting. The strains elicited core responses to alkaline growth including modulation of intracellular pH, stabilisation of cellular processes and reduced cell-division, independent to lineage, MLST or whether the strains were transient or persistent contaminants. Alkaline adaptation by all strains corresponded to that expected in stringent-response induced cells, with protein expression supporting metabolic shifts concordant with elevated alarmone production and indicating that the alkaline-stringent response results from energy rather than nutrient limitation. We believe this is the first report describing induction of a stringent response in different L. monocytogenes strains by alkaline pH under non-limiting growth conditions. The work emphasises the need for early intervention to avoid persistent food factory contamination by L. monocytogenes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. A simple route to synthesize conductive stimuli-responsive polypyrrole nanocomposite hydrogel particles with strong magnetic properties and their performance for removal of hexavalent chromium ions from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Hasan, E-mail: samarhass@yahoo.com [Department of Chemistry, Rajshahi University, Rajshahi 6205 (Bangladesh); Rahman, Mohammad Mostafizar; Ali, Mohammad Azgar [Department of Chemistry, Rajshahi University, Rajshahi 6205 (Bangladesh); Minami, Hideto [Graduate School of Engineering, Kobe University, Kobe 657-8501 (Japan); Tauer, Klaus [Max Planck Institute of Colloid and Interfaces, Am Mühlenberg, 14476 Golm (Germany); Gafur, Mohammad Abdul [Pilot Plant and Process Development Centre, BCSIR, Dhaka 1205 (Bangladesh); Rahman, Mohammad Mahbubor [Department of Chemistry, Rajshahi University, Rajshahi 6205 (Bangladesh)

    2016-08-15

    A combination of maghemite polypyrrole (PPy/γ-Fe{sub 2}O{sub 3}) and stimuli-responsive properties in the same hydrogel microspheres is expected to enhance their application potential in various fields such as tissue engineering, regenerative medicine, biosensors, biomedical applications and removal of heavy metals from waste water, catalysis etc. In this investigation a simple two step process is used to prepare conductive stimuli-responsive polypyrrole (PPy) composite hydrogel particles with strong magnetic properties. Poly(styrene-methacrylic acid-N-isopropylacrylamide-polyethelene glycol methacrylate) or P(S-NIPAM-MAA-PEGMA) hydrogel seed particles are first prepared by soap-free precipitation copolymerization. The copolymer hydrogel particles exhibited both temperature- and pH-responsive volume phase transition. Conductive P(S-NIPAM-MAA-PEGMA)/PPy/γ-Fe{sub 2}O{sub 3} nanocomposite hydrogel particles are then prepared by seeded chemical oxidative polymerization of pyrrole in the presence of P(S-NIPAM-MAA-PEGMA) hydrogel seed particles using FeCl{sub 3} as a oxidant and p-toluene sulfonic acid ( p-TSA) as a dopant. In the reaction system FeCl{sub 3} functioned as a source of Fe(III) for the formation of γ-Fe{sub 2}O{sub 3}. This reaction also requires the initial presence of Fe(II) provided by the addition of FeCl{sub 2}. The size and size distribution, surface structure, and morphology of the prepared conductive composite hydrogel particles are confirmed by FTIR, electron micrographs, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV–visible spectroscopy. The performance of nanocomposite hydrogel particles has been evaluated for the removal of hexavalent chromium (Cr) ions from water. - Highlights: • P(S-NIPAM-MAA-PEGMA) hydrogel particles were prepared. • P(S-NIPAM-MAA-PEGMA)/PPy/γ-Fe{sub 2}O{sub 3} nanocomposite hydrogel particles were prepared. • Oxidative polymerization of pyrrole and precipitation of γ-Fe{sub 2}O{sub 3

  9. Wave Breaking Phenomenon for DGH Equation with Strong Dissipation

    Directory of Open Access Journals (Sweden)

    Zhengguang Guo

    2014-01-01

    Full Text Available The present work is mainly concerned with the Dullin-Gottwald-Holm (DGH equation with strong dissipative term. We establish some sufficient conditions to guarantee finite time blow-up of strong solutions.

  10. Multiscale Alterations in Sugar Cane Bagasse and Straw Submitted to Alkaline Deacetylation

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Cleilton S. [Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, São Paulo, Brazil; Department of Biotechnology, Engineering College of Lorena, University of São Paulo, 12602-810 Lorena, São Paulo, Brazil; Rabelo, Sarita C. [Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, São Paulo, Brazil; Ciesielski, Peter N. [Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Roberto, Inês C. [Department of Biotechnology, Engineering College of Lorena, University of São Paulo, 12602-810 Lorena, São Paulo, Brazil; Rocha, George J. M. [Department of Biotechnology, Engineering College of Lorena, University of São Paulo, 12602-810 Lorena, São Paulo, Brazil; Driemeier, Carlos [Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, São Paulo, Brazil

    2018-01-31

    Alkaline deacetylation has emerged as a promising chemistry for pretreatments performed prior to enzymatic saccharification of lignocellulosic biomass. This process avoids complex pressurized reactors and opens new opportunities for lignin covalorization. In this work, we evaluate the chemical and morphological response of sugar cane bagasse and straw submitted to alkaline treatments. Alkaline solutions for deacetylation (0.4% w/w NaOH, 70 degrees C, 3 h) as well as proximal conditions (0.1-0.7% NaOH, 55-85 degrees C, 1-5 h) chosen by 23 experimental design were evaluated. The deacetylation treatment removes ~90% of the acetyl groups and 20-30% of the lignin from both bagasse and straw, while removal of ~20% of the xylan and glucan is observed in straw, but not in bagasse. Considering nanoscale structural alterations, neither cellulose cocrystallization (evaluated by X-ray diffraction) nor formation of lignin aggregates (evaluated by thermoporometric signature) are observed after the alkaline conditions, in contrast to observations after hydrothermal treatments. Furthermore, calorimetric thermoporometry as well as scanning and transmission electron microscopies show substantial introduction of nanoscale porosity and loosening of the tissue and cell wall structures, indicating desirable mechanical weakening and gains in enzyme accessibility. These results provide fundamental and practical knowledge for biorefineries based on alkaline deacetylation of sugar cane bagasse and straw.

  11. Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents.

    Science.gov (United States)

    Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua

    2017-12-01

    Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H 2 and CO 2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.

  12. Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents

    Science.gov (United States)

    Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua

    2017-12-01

    Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H2 and CO2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.

  13. The viability of MCM-41 as separator in secondary alkaline cells

    Science.gov (United States)

    Meskon, S. R.; Othman, R.; Ani, M. H.

    2018-01-01

    The viability of MCM-41 membrane as a separator material in secondary alkaline cell is investigated. The inorganic membrane was employed in an alkaline nickel-zinc system. MCM-41 mesoporous material consists of arrays of hexagonal nano-pore channels. The membrane was synthesized using sol-gel route from parent solution comprising of quarternary ammonium surfactant, cethyltrimethylammonium bromide C16H33(CH3)3NBr (CTAB), hydrochloric acid (HCl), deionized water (H2O), ethanol (C2H5OH), and tetraethylortosilicate (TEOS). Both the anodic zinc/zinc oxide and cathodic nickel hydroxide electrodeposited film were coated with MCM-41 membrane. The Ni/MCM-41/Zn alkaline cell was then subjected to 100-cycle durability test and the structural stability of MCM-41 separator throughout the progression of the charge-discharge cycles is studied. X-ray diffraction (XRD) analysis on the dismantled cell shows that MCM-41 began to transform to lamellar MCM-50 on the 5th cycle and transformed almost completely on the 25th cycle. The phase transformation of MCM-41 hexagonal structure into gel-like MCM-50 prevents the mesoporous cell separator from diminished in the caustic alkaline surround. This work has hence demonstrated MCM-41 membrane is viable to be employed in secondary alkaline cells.

  14. Determination of Acidity and Alkalinity of Food Materials

    OpenAIRE

    三浦,芳助; 福永,祐子; 瀧川,裕里子; 津田,真美; 渡辺,陽子; 瀨山,一正

    2006-01-01

    The acidity and alkalinity of food materials in various menus was determined to clarify the influence of food on physiological functions. Menus mainly containing alkaline food materials (alkaline menu) and acid ones (acid menu) were compared. Determination of acidity and alkalinity was performed for each food material in the alkaline menu and acid menu, and acidity and alkalinity of one meal and a day's one were estimated. 1. Most of food materials in acid menu were assessed to be...

  15. Production optimization of a heat-tolerant alkaline pectinase from Bacillus subtilis ZGL14 and its purification and characterization.

    Science.gov (United States)

    Yu, Ping; Zhang, Yishu; Gu, Donglu

    2017-09-03

    Alkaline pectinase has important applications in the pretreatment of waste water from food processing and in both the fabric and paper industries. In this study, a 2-level factorial design was used to screen significant factors that affect the activity of alkaline pectinase, and the response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize their concentrations. Starch, peptone, KH 2 PO 4 and K 2 HPO 4 ·3H 2 O were found to significantly affect the activity of alkaline pectinase. Their optimal concentrations were as follows: 4.68% starch, 1.6% peptone, 0.26% KH 2 PO 4 and 0.68% K 2 HPO 4 ·3H 2 O. Under the above conditions, the activity of alkaline pectinase was significantly improved to 734.11 U/mL. Alkaline pectinase was purified to homogeneity with a recovery rate of 9.6% and a specific activity of 52372.52 U/mg. Its optimal temperature and pH were 50°C and 8.6, respectively. The purified enzyme showed strong thermo-stability and good alkali resistance. In addition, the activity of alkaline pectinase was improved in the presence of Mg 2+ . Cu 2+ , Mn 2+ , and Co 2+ significantly inhibited its activity. This study provides an important basis for the future development and use of a heat-tolerant alkaline pectinase from B. subtilis ZGL14.

  16. Transpassive electrodissolution of depleted uranium in alkaline electrolytes

    International Nuclear Information System (INIS)

    Weisbrod, K.R.; Schake, A.R.; Morgan, A.N.; Purdy, G.M.; Martinez, H.E.; Nelson, T.O.

    1998-03-01

    To aid in removal of oralloy from the nuclear weapons stockpile, scientists at the Los Alamos National Laboratory Plutonium Facility are decontaminating oralloy parts by electrodissolution in neutral to alkaline electrolytes composed of sodium nitrate and sodium sulfate. To improve the process, electrodissolution experiments were performed with depleted uranium to understand the effects of various operating parameters. Sufficient precipitate was also produced to evaluate the feasibility of using ultrafiltration to separate the uranium oxide precipitates from the electrolyte before it enters the decontamination fixture. In preparation for the experiments, a potential-pH diagram for uranium was constructed from thermodynamic data for fully hydrated species. Electrodissolution in unstirred solutions showed that uranium dissolution forms two layers, an acidic bottom layer rich in uranium and an alkaline upper layer. Under stirred conditions results are consistent with the formation of a yellow precipitate of composition UO 3 ·2H 2 O, a six electron process. Amperometric experiments showed that current efficiency remained near 100% over a wide range of electrolytes, electrolyte concentrations, pH, and stirring conditions

  17. Efficiency of alkaline hydrolysis method in environment protection.

    Science.gov (United States)

    Kricka, Tajana; Toth, Ivan; Kalambura, Sanja; Jovicić, Nives

    2014-06-01

    Development of new technologies for the efficient use of proteins of animal origin, apart from heat treatment in rendering facilities that was used to date, has become the primary goal of the integral waste management system. The emergence of bovine spongiform encephalopathy in Europe and in the World in the 1990s opened up new questions regarding medical safety and use of meat bone meal in the animal feed, which is produced by processing animal waste. Animal waste is divided into three categories, out of which the first category is high-risk waste. Alkaline hydrolysis is alternative method for management of animal by-products not intended for human diet and imposes itself as one of the solutions for disposal of high-risk proteins. The paper will present the analyses of animal by-products not intended for human diet treated in laboratory reactor for alkaline hydrolysis, as one of the two recognized methods in EU for the disposal of this type of material and use in fertilization.

  18. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    Directory of Open Access Journals (Sweden)

    Gerry K. Schwalfenberg

    2012-01-01

    Full Text Available This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

  19. Intestinal alkaline phosphatase: novel functions and protective effects.

    Science.gov (United States)

    Lallès, Jean-Paul

    2014-02-01

    Important protective roles of intestinal alkaline phosphatase (IAP)--including regulation of intestinal surface pH, absorption of lipids, detoxification of free nucleotides and bacterial lipopolysaccharide, attenuation of intestinal inflammation, and possible modulation of the gut microbiota--have been reviewed recently. IAP is modulated by numerous nutritional factors. The present review highlights new findings on the properties of IAP and extends the list of its protective functions. Critical assessment of data suggests that some IAP properties are a direct result of dephosphorylation of proinflammatory moieties, while others (e.g., gut barrier protection and microbiota shaping) may be secondary to IAP-mediated downregulation of inflammation. IAP and tissue-nonspecific alkaline phosphatase isoforms characterize the small intestine and the colon, respectively. Gastrointestinal administration of exogenous IAP ameliorates gut inflammation and favors gut tissue regeneration, whereas enteral and systemic IAP administration attenuates systemic inflammation only. Finally, the IAP gene family has a strong evolutionary link to food-driven changes in gastrointestinal tract anatomy and microbiota composition. Therefore, stimulation of IAP activity by dietary intervention is a goal for preserving gut homeostasis and health by minimizing low-grade inflammation. © 2013 International Life Sciences Institute.

  20. Effect of alkaline pretreatment on delignification of wheat straw.

    Science.gov (United States)

    Asghar, Umar; Irfan, Muhammad; Iram, Mehvish; Huma, Zile; Nelofer, Rubina; Nadeem, Muhammad; Syed, Quratulain

    2015-01-01

    This study was conducted to analyse structural changes through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) after alkaline pretreatment of wheat straw for optimum steaming period. During the study, 2 mm size of substrate was soaked in 2.5% NaOH for 1 h at room temperature and then autoclaved at 121°C for various steaming time (30, 60, 90 and 120 min). Results revealed that residence time of 90 min at 121°C has strong effect on substrate, achieving a maximum cellulose content of 83%, delignification of 81% and hemicellulose content of 10.5%. Further SEM and FTIR spectroscopy confirmed structural modification caused by alkaline pretreatment in substrate. Maximum saccharification yield of 52.93% was achieved with 0.5% enzyme concentration using 2.5% substrate concentration for 8 h of incubation at 50°C. This result indicates that the above-mentioned pretreatment conditions create accessible areas for enzymatic hydrolysis.

  1. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  2. Potentiometric assay for acid and alkaline phosphatase

    International Nuclear Information System (INIS)

    Koncki, Robert; Ogonczyk, Dominika; Glab, Stanislaw

    2005-01-01

    Simple potentiometric kinetic assay for evaluation of acid and alkaline phosphatase activity has been developed. Enzymatically catalyzed hydrolysis of monofluorophosphate, the simplest inorganic compound containing P-F bond, has been investigated as the basis of the assays. Fluoride ions formed in the course of the hydrolysis of this specific substrate have been detected using conventional fluoride ion-selective electrode based on membrane made of lanthanum fluoride. The key analytical parameters necessary for sensitive and selective detection of both enzymes have been assessed. Maximal sensitivity of the assays was observed at monofluorophosphate concentration near 10 -3 M. Maximal sensitivity of acid phosphatase assay was found at pH 6.0, but pH of 4.8 is recommended to eliminate effects from alkaline phosphatase. Optimal pH for alkaline phosphatase assay is 9.0. The utility of the developed substrate-sensor system for determination of acid and alkaline phosphatase activity in human serum has been demonstrated

  3. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)

    user

    applications in the field of optical fibers, optoelectronic devices; radiation shields, surgical lasers and their glass ceramic counter parts have wide range of applications (Rajasree et al., 2011; Sharma et al., 2007, Limkitjaroenporn et al., 2010). Boric acid. (H3BO3) form stable glasses with alkaline earth oxides (R= MgO, CaO, ...

  4. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    IAS Admin

    and yellow colour appears. Initial colour remains but fades. Orange colour appears. Yellow colour appears. Carbohydrates. Monosaccharide. Disaccharide. + Alkaline ferricyanide (shake for 5 minutes). Colour disappears. Colour does not disappear. Put the test tube in boiling water for 10 seconds. Put the test tube in boiling.

  5. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... the metal ions tested. Key words: Alkaline protease, casein agar, meat waste contaminated soil, Pseudomonas fluorescens. INTRODUCTION. Proteases are the most important industrial enzymes that execute a wide variety of functions and have various important biotechnological applications (Mohen et al.,.

  6. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  7. Alkaline earth metal catalysts for asymmetric reactions.

    Science.gov (United States)

    Kobayashi, Shū; Yamashita, Yasuhiro

    2011-01-18

    The group 2 alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) are among the most common elements on Earth, abundant in both the sea and the Earth's crust. Although they are familiar in our daily lives, their application to organic synthesis has, so far, been limited. Some particularly useful properties of these elements include (i) low electronegativity, (ii) a stable oxidation state of +2, meaning that they can potentially form two covalent bonds with anions, and (iii) the ability to occupy a variety of coordination sites due to their large ionic radius. Furthermore, the alkaline earth metals, found between the group 1 and group 3 elements, show mild but significant Lewis acidity, which can be harnessed to control coordinative molecules via a Lewis acid-base interaction. Taken together, these characteristics make the metals Ca, Sr, and Ba very promising components of highly functionalized acid-base catalysts. In this Account, we describe the development of chiral alkaline earth metal catalysts for asymmetric carbon-carbon bond-forming reactions. Recently prepared chiral alkaline earth metal complexes have shown high diastereo- and enantioselectivities in fundamental and important chemical transformations. We chose chiral bisoxazoline (Box) derivatives bearing a methylene tether as a ligand for chiral modification. These molecules are very useful because they can covalently coordinate to alkaline earth metals in a bidentate fashion through deprotonation of the tether portion. It was found that chiral calcium-Box complexes could successfully promote catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions with high diastereo- and enantioselectivities. Both the calcium-Box complexes and chiral strontium-bis-sulfonamide and chiral barium-BINOLate complexes could catalyze asymmetric 1,4-addition reactions with high enantioselectivities. Furthermore, we designed a calcium-neutral coordinative ligand complex as a new type of chiral alkaline

  8. Non-polluting treatment of uranium effluents from the alkaline digestion of an uranium ore containing sulfur

    International Nuclear Information System (INIS)

    Berger, Bernard.

    1978-01-01

    New non-polluting process for treating uranium effluents from the alkaline digestion of an uranium ore containing sulphur, which makes it possible (a) to extract and obtain relatively pure uranium and (b) to process the digestion liquor freed from the uranium and containing in an aqueous solution a mixture of alkaline carbonate and/or bicarbonate and sodium sulphate, consisting in the selective extraction of the sodium sulphate present and the recycling of the liquor free of SO 4 = ions, containing in solution the sole carbonates and/or bicarbonates involved, towards the digestion of the ore [fr

  9. Binding sites of chlorpheniramine on 1:1 layered kaolinite from aqueous solution.

    Science.gov (United States)

    Lv, Guocheng; Wu, Limei; Li, Zhaohui; Liao, Libing; Liu, Meitang

    2014-06-15

    Interactions between chlorpheniramine (CP), an antihistamine drug used to treat allergy, and kaolinite in aqueous solution were investigated under batch studies and molecular simulations. The CP adsorption was relatively fast with a large rate constant. The CP adsorption capacity on kaolinite was 25 mmol/kg, about the same magnitude of the cation exchange capacity of kaolinite. Molecular dynamic simulation showed that the edges of kaolinite were responsible for the uptake of CP, while a net repulsive interaction between the basal plane and CP molecules was obtained. As the broken bond effect of kaolinite was strongly affected by solution pH via protonation-deprotonation of kaolinite edges, a higher CP adsorption was achieved under neutral to weak alkaline solution. It was the charge density, rather than the surface area, that ultimately controlled the amount of CP adsorption on kaolinite. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Alkaline-cell lysis through in-line static mixer reactor for the production of plasmid DNA for gene therapy.

    Science.gov (United States)

    Chamsart, Saethawat; Karnjanasorn, Tanyawat

    2007-02-15

    A state-of-the-art in-line static mixer reactor (ISMR) was invented to lyse E. coli cells and neutralize the cell lysate continuously and efficiently for the extraction of plasmid DNA. It comprised two connected static dynamic mixers, each 0.01 m in diameter and 0.9 m in length, one for lysis and one for neutralization. Cells were lysed using concentrated alkaline with 1% SDS and the lysate was neutralized at feed rates of cell suspension:lysis solution:neutralization solution of 125:250:125, 250:500:250, and 500:1,000:500 mL/min. Distances for the mixtures to reach color homogeneity were dependent on feed rates. The higher the feed rates the shorter the mixing distances and times. However, complete cell lysis and neutralization were independent of color homogeneity. Lysate viscosity and neutralized floc size decreased and floc density increased, as distances and feed rates increased. High plasmid yields were obtained from both lysis and neutralization at feed rate ratios of 125:250:125 and 250:500:250 mL/min within mixing distances or =0.6 m at all feed rates due to a longer exposure to strong alkali and shear flow. This invention showed excellent performance with scaleable potential for the commercial manufacture of plasmid DNA.

  11. Alkaline hydrothermal treatment of brominated high impact polystyrene (HIPS-Br) for bromine and bromine-free plastic recovery.

    Science.gov (United States)

    Brebu, Mihai; Bhaskar, Thallada; Muto, Akinori; Sakata, Yusaku

    2006-08-01

    A method to recover both Br and Br-free plastic from brominated flame retardant high impact polystyrene (HIPS-Br) was proposed. HIPS-Br containing 15% Br was treated in autoclave at 280 degrees C using water or KOH solution of various amounts and concentrations. Hydrothermal treatment (30 ml water) leads to 90% debromination of 1g HIPS-Br but plastic is strongly degraded and could not be recovered. Alkaline hydrothermal treatment (45 ml or 60 ml KOH 1M) showed similar debromination for up to 12 g HIPS-Br and plastic was recovered as pellets with molecular weight distribution close to that of the initial material. Debromination occurs at melt plastic/KOH solution interface when liquid/vapour equilibrium is attained inside autoclave (280 degrees C and 7 MPa in our experimental conditions) and depends on the plastic amount/KOH volume ratio. The antimony oxide synergist from HIPS-Br remains in recovered plastic during treatment. A pictorial imagination of the proposed debromination process is presented.

  12. A new method for alkaline dissolution of uranium metal foil

    International Nuclear Information System (INIS)

    Mondino, A.V.; Wilkinson, M.V.; Manzini, A.C.

    2001-01-01

    In order to develop a production process of 99 Mo by fission of low-enriched uranium, the first purification step, which consists of dissolution of a uranium metal foil target, was studied. It was found that alkaline NaClO gave good results, reaching the dissolution of up to 300 μm of uranium foil. The different conditions for the dissolution were studied and the optimum ones were found. The influence of NaClO and NaOH concentration, temperature, dissolving solution volume per unit of surface and dissolution time were investigated. During this step, a gas identified as H 2 , was generated, and a precipitate characterized as Na 2 U 2 O 7 was observed. A stoichiometric reaction for this uranium dissolution is proposed. (author)

  13. Osteocalcin and bone-specific alkaline phosphatase in Sickle cell ...

    African Journals Online (AJOL)

    specific alkaline phosphatase (b-AP) total protein levels were evaluated as indicators of bone turnover in twenty patients with sickle cell haemoglobinopathies and in twenty normal healthy individuals. The serum bonespecific alkaline phosphatase ...

  14. Modification of the Selectivity Properties of Tubular Ceramic Membranes after Alkaline Treatment

    Directory of Open Access Journals (Sweden)

    Patrick Dutournié

    2017-11-01

    Full Text Available This work focuses on the selectivity modification of ceramic membranes after a mild alkaline treatment. Filtration of pure salt-water solutions was carried out with commercial titania membranes before and after the treatment. After treatment, the rejection of NaF significantly decreased, while the rejection of NaCl and NaBr increased. Additionally, NaI and Na2SO4 remained close to zero. Pore size and electrical charge being almost unchanged, only significant modifications in the dielectric effects can explain this modification of selectivity. Therefore, the surface chemistry and the interaction (nature and magnitude with the solvent and with the species present in the solution appear to be modified by the alkaline treatment. This trend is also illustrated by discussing the electric and the dielectric properties that were numerically identified before and after treatment. The alkaline treatment significantly decreased the apparent dielectric constant of NaCl-water solution in the pore, highlighting the rejection of sodium chloride. Contrariwise, the modification of the surface chemistry increased the apparent dielectric constant of NaF-water solution by promoting fluoride transmission.

  15. Leaching of the antimony and accompanying of elements Sb2S3 in the alkaline medium

    Directory of Open Access Journals (Sweden)

    Dagmar Remeteiová

    2007-06-01

    Full Text Available This paper presents results of the laboratory investigation of alkaline leaching of stibnite that is an important mineral occuring in the antimony-bearing raw materials. The following components were present in stibnite: Sb2S3, SiO2, ZnS, FeS2. The aim of this study was to establish the effect of composition of the aqueous alkaline leaching medium (1 % NaOH, 1 % NaOH + 1 % Na2S2O3, 1 % NaOH + 1 % Na2S on the recoveries of Sb, Fe, Pb, Zn, Cu, Ni and Hg. The antimony recoveries in the leaching solutions NaOH and NaOH + Na2S2O3 solutions were lower in comparison with the leaching in NaOH + Na2S. The Fe, Pb, Zn recoveries in alkaline solutions were found to decrease in the following order: Fe, Pb, Zn. The mercury recovery in the leaching test with the solution containing 1 % NaOH+1 % Na2S was 3,7 %.

  16. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  17. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  18. The heterogeneous reactions of silica, titania and zirconia with alkaline-earth metal oxides in metal chloride melts - to form alkaline-earth metal silicates titanates and zirconates. 1

    International Nuclear Information System (INIS)

    Packter, A.; Zaidi, S.A.

    1982-01-01

    The solubility versus temperature phase diagrams, for calcium, strontium and barium oxide (silicate and titanate) solutions in the metal chloride melts at 800 to 1400 0 C, have been analysed. The alkaline-earth metal oxide solutions are binary mixtures with solvate formation and the liquid phases probably contain [O . 4 MCl 2 ] 2- , [O . MCl 2 ] 2- and O 2- anions. The alkaline-earth metal metsilicate solutions are non-ideal binary mixtures and the liquid phases probably contain mainly Si 3 O 9 6- anions: the orthosilicate solutions probably contain [SiO 4 . MCl 2 ] 4- and SiO 4 4- anions. The alkaline-earth metal titanate solutions are ideal binary mixtures upto titanate mole fraction 0.3-0.6 and the liquid phases probably contain only TiO 3 2- anions. The overall ionic equilibria, occurring in the liquid phases during the chemical reactions of silica (and titania) with alkaline-earth metal oxides in metal chloride melts in this temperature range, were thence assessed. (author)

  19. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  20. Optimal Surface Amino-Functionalization Following Thermo-Alkaline Treatment of Nanostructured Silica Adsorbents for Enhanced CO2 Adsorption

    Directory of Open Access Journals (Sweden)

    Obdulia Medina-Juárez

    2016-11-01

    Full Text Available Special preparation of Santa Barbara Amorphous (SBA-15, mesoporous silica with highly hexagonal ordered, these materials have been carried out for creating adsorbents exhibiting an enhanced and partially selective adsorption toward CO2. This creation starts from an adequate conditioning of the silica surface, via a thermo-alkaline treatment to increase the population of silanol species on it. CO2 adsorption is only reasonably achieved when the SiO2 surface becomes aminated after put in contact with a solution of an amino alkoxide compound in the right solvent. Unfunctionalized and amine-functionalized substrates were characterized through X-ray diffraction, N2 sorption, Raman spectroscopy, electron microscopy, 29Si solid-state Nuclear Magnetic Resonance (NMR, and NH3 thermal programmed desorption. These analyses proved that the thermo-alkaline procedure desilicates the substrate and eliminates the micropores (without affecting the SBA-15 capillaries, present in the original solid. NMR analysis confirms that the hydroxylated solid anchors more amino functionalizing molecules than the unhydroxylated material. The SBA-15 sample subjected to hydroxylation and amino-functionalization displays a high enthalpy of interaction, a reason why this solid is suitable for a strong deposition of CO2 but with the possibility of observing a low-pressure hysteresis phenomenon. Contrastingly, CH4 adsorption on amino-functionalized, hydroxylated SBA-15 substrates becomes almost five times lower than the CO2 one, thus giving proof of their selectivity toward CO2. Although the amount of retained CO2 is not yet similar to or higher than those determined in other investigations, the methodology herein described is still susceptible to optimization.

  1. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  2. Coulomb plus strong interaction bound states - momentum space numerical solutions

    International Nuclear Information System (INIS)

    Heddle, D.P.; Tabakin, F.

    1985-01-01

    The levels and widths of hadronic atoms are calculated in momentum space using an inverse algorithm for the eigenvalue problem. The Coulomb singularity is handled by the Lande substraction method. Relativistic, nonlocal, complex hadron-nucleus interactions are incorporated as well as vacuum polarization and finite size effects. Coordinate space wavefunctions are obtained by employing a Fourier Bessel transformation. (orig.)

  3. Genesis of post-collisional calc-alkaline and alkaline granitoids in Qiman Tagh, East Kunlun, China

    Science.gov (United States)

    Yu, Miao; Feng, Chengyou; Zhao, Yiming; Li, Daxin

    2015-12-01

    The post-collisional magmatism of Qiman Tagh is characterized by the intrusion of voluminous intermediate to felsic granitoids, including syenogranite, monzogranite, granodiorite, tonalite and diorite. The granitoids can be divided into two magmatic suites: Calc-alkaline (CA) and alkaline (Alk), which were emplaced from ~ 236 Ma to ~ 204 Ma. The CA suite contains metaluminous granodiorites and monzogranites. Typical Qiman Tagh CA granodiorites show moderately fractionated REE patterns ((La/Yb)N = 4.35-25.11) with significant negative Eu anomalies (Eu/Eu* = 0.54-1.34), and the primitive mantle-normalized spidergrams show strong depletion of Nb and Sr. The Qiman Tagh CA monzogranites show similar fractionated REE patterns ((La/Yb)N = 2.70-13.5) with less prominent negative Eu anomalies, and the chondrite-normalized spidergrams show strongly depleted Ba, Nb and Sr. The Alk suite, including syenogranite, is highly potassic (K2O/Na2O = 1.09-3.56) and peraluminous (A/CNK = 0.91-1.06). Compared to typical Qiman Tagh CA granodiorites, the Qiman Tagh Alk granitoids can be distinguished by their higher Rb, Nb, Ga/Al, FeO*/MgO, Y/Sr and Rb/Sr, as well as their lower Mg#, MgO, CaO, Al2O3, Sr, Co, V, Eu/Eu*, Ba/Nb, La/Nb, Ba/La and Ce/Nb. The Qiman Tagh CA rocks were most likely to be derived from the partial melting of garnet-amphibolite-facies rocks in the lower crust, leaving behind anhydrous granulite-facies rocks with plagioclase and garnet in the residue. The Alk rocks may have formed by the continued partial melting of granulite-facies rocks at elevated temperatures (> 830 °C).

  4. Photolysis of alkaline-earth nitrates

    Science.gov (United States)

    Kriger, L. D.; Miklin, M. B.; Dyagileva, E. P.; Anan'ev, V. A.

    2013-02-01

    Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta-1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta-1 for Sr(NO3)2, Ba(NO3)2, Ca(NO3)2 · 4H2O, and Mg(NO3)2 · 6H2O, respectively.

  5. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  6. Purification and characterisation of alkaline phosphotase enzyme ...

    African Journals Online (AJOL)

    L'enzyme phosphatase alkaline était purifié de la bactérie Escherichia coli C90 cultivé dans un médium pauvre en phosphate comme phase stationnaire utilisant une colonne d'échange d'ion enveloppée avec une cellulose DEAE comme matrice et exclusion de taille chromographique utilisant le Sepharcryl S-300HR ...

  7. Stainless steel anodes for alkaline water electrolysis and methods of making

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  8. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  9. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  10. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  11. Impact of alkaline alterations to a Brazilian soil on cesium retention under low temperature conditions.

    Science.gov (United States)

    Calábria, Jaqueline Alves de Almeida; Cota, Stela Dalva Santos; de Morais, Gustavo Ferrari; Ladeira, Ana Cláudia Queiroz

    2017-11-01

    To be used as backfilling materials in radioactive waste disposal facilities, a natural material must have a suitable permeability, mechanical properties and a high sorption capacity for radionuclides. Also important when considering a material as a backfill is the effect of its interaction with the alkaline solution generated from concrete degradation. This solution promotes mineralogical alterations that result in significant changes in the material key properties influencing its performance as a safety component of the repository. This paper presents results of an investigation on the effect of alkaline interaction under a low temperature on cesium retention properties of a local soil being considered suitable as a backfill for the Brazilian near surface disposal facility. A sample of the Brazilian soil was mixed with an alkaline solution, simulating the pore water leached in the first stage of cement degradation, during 1, 7, 14 and 28 days. The experiments were conducted under low temperature (25 °C) aiming to evaluate similar conditions found on a low and intermediate level radioactive waste disposal installation. A non-classical isotherm sorption model was fitted to sorption data obtained from batch experiments, for unaltered and altered samples, providing parameters that allowed us to assess the effect of the interaction on material quality as Cs sorbent. The sorption parameters obtained from the data-fitted isotherm were used then to estimate the corresponding retardation factor (R). Alkaline interaction significantly modified the soil sorption properties for Cs. The parameter Q, related to the maximum sorption capacity, as well as the affinity parameter (K) and the retardation coefficients became significantly smaller (about 1000 times for the R coefficient) after pretreatment with the simulated alkaline solutions. Moreover, the increase in n-values, which is related with the energy distribution width and heterogeneity of surface site energies

  12. State of the Art on Cactus Additions in Alkaline Media as Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    A. A. Torres-Acosta

    2012-01-01

    Full Text Available This research in progress includes results on the corrosion performance of reinforcing steel in alkaline media when two different dehydrated cacti (Opuntia ficus-indica—Nopal—and Aloe Vera were used as additions in pH 12.5 and 13.3 solutions and in concrete. The dehydrated cactus addition was mixed at different concentrations by either solution or cement mass (0.10%, 0.25%, 0.5%, 1.0%, and 2.0%. Half-cell potentials and LPR measurements were performed at different time periods to characterize the possible corrosion inhibiting effect of the cactus additions tested in such alkaline media. Results showed good corrosion inhibiting effect of dehydrated Nopal on reinforcing steel, in all tested solutions, when chloride ions are present. Aloe Vera did show also corrosion inhibiting improvements in some extent. The addition of such cactus led to an apparent formation of a denser and more packed oxide/hydroxide surface layer on the steel surface that decreased corrosion activity. This oxide/hydroxide layer growth was confirmed by microscopic evaluation of the metal surface layer performed at the end of the research program. The preliminary findings suggest that adding Nopal at concentrations between 1% and 2%, by mass, might be suitable for durability enhancing applications in alkaline media, especially in concrete structures.

  13. Gene Expression Profiling of Iron Deficiency Chlorosis Sensitive and Tolerant Soybean Indicates Key Roles for Phenylpropanoids under Alkalinity Stress

    Directory of Open Access Journals (Sweden)

    Brian M. Waters

    2018-01-01

    Full Text Available Alkaline soils comprise 30% of the earth and have low plant-available iron (Fe concentration, and can cause iron deficiency chlorosis (IDC. IDC causes soybean yield losses of $260 million annually. However, it is not known whether molecular responses to IDC are equivalent to responses to low iron supply. IDC tolerant and sensitive soybean lines provide a contrast to identify specific factors associated with IDC. We used RNA-seq to compare gene expression under combinations of normal pH (5.7 or alkaline pH (7.7, imposed by 2.5 mM bicarbonate, or pH 8.2 imposed by 5 mM bicarbonate and normal (25 μM or low (1 μM iron conditions from roots of these lines. Thus, we were able to treat pH and Fe supply as separate variables. We also noted differential gene expression between IDC sensitive and tolerant genotypes in each condition. Classical iron uptake genes, including ferric-chelate reductase (FCR and ferrous transporters, were upregulated by both Fe deficiency and alkaline stress, however, their gene products did not function well at alkaline pH. In addition, genes in the phenylpropanoid synthesis pathway were upregulated in both alkaline and low Fe conditions. These genes lead to the production of fluorescent root exudate (FluRE compounds, such as coumarins. Fluorescence of nutrient solution increased with alkaline treatment, and was higher in the IDC tolerant line. Some of these genes also localized to previously identified QTL regions associated with IDC. We hypothesize that FluRE become essential at alkaline pH where the classical iron uptake system does not function well. This work could result in new strategies to screen for IDC tolerance, and provide breeding targets to improve crop alkaline stress tolerance.

  14. Inactivation of peroxidase, pectinesterase and alkaline phosphatase in polymers as a model for irradiation of dried foodstuffs

    NARCIS (Netherlands)

    Roozen, J.P.

    1972-01-01

    This thesis consists of a summary only of 6 refereed scientific papers published in Lebensmittel -Wissenschaft und -Technologie 3, 37-40 (1970); 4, 24-26, 93-96, 158-162, 196-200 (1971); 5, 128-131 (1972).

    Aqueous solutions containing an enzyme (peroxidase, alkaline phosphatase,

  15. Simulated bioavailability of phosphorus from aquatic macrophytes and hytoplankton by aqueous suspension and incubation with alkaline phosphatase

    Science.gov (United States)

    Bioavailability of phosphorus (P) in aquatic macrophytes and algae on lake eutrophication was studied by evaluation their P forms and quantities in their water suspensions and impact by alkaline phosphatase hydrolysis. using solution 31P-nuclear magnetic resonance (NMR). The laboratory suspension an...

  16. Alkaline hydrolysis of dimethyl terephthalate in the presence of [LiAl2(OH)6]Cl.2H2O

    International Nuclear Information System (INIS)

    Lei Lixu; Zhang Weifeng; Hu Meng; Zheng Hegen

    2006-01-01

    The alkaline hydrolysis of dimethyl terephthalate (DMT) in the presence of [LiAl 2 (OH) 6 ]Cl has been investigated to demonstrate a possible application of anion exchange facility of layered double hydroxides (LDHs) to control chemical reactions. The results show that (i) in the alkaline hydrolysis of DMT in the presence of [LiAl 2 (OH) 6 ]Cl, most of the interlayer Cl - of [LiAl 2 (OH) 6 ]Cl is quickly replaced by OH - in the alkaline solution because the LDH host favors OH - more; (ii) the alkaline hydrolysis of DMT in the presence of [LiAl 2 (OH) 6 ]Cl is faster than the reaction of DMT and [LiAl 2 (OH) 6 ]OH; (iii) The hydrolysis of DMT in a buffer solution of pH∼8 takes longer time to reach equilibrium than the alkaline hydrolysis of DMT in the presence of [LiAl 2 (OH) 6 ]Cl. It is believed that the selective anion exchange chemistry of the LDH plays a key role in storage and controlled release of active reactant, that is, OH - , thus make the hydrolysis proceeds in a controlled way. - Graphical abstract: XRD patterns of the solid products of the alkaline hydrolysis of dimethyl terephthalate (DMT) in the presence of [LiAl 2 (OH) 6 ]Cl at 70 deg. C halted at different time, which shows that [LiAl 2 (OH) 6 ]Cl turns out to be [LiAl 2 (OH) 6 ]OH, and [LiAl 2 (OH) 6 ] 2 TP forms gradually. In this reaction, the alkaline hydrolysis of DMT is controlled by replacement of Cl - in [LiAl 2 (OH) 6 ]Cl by OH - , and subsequent replacement of OH - in [LiAl 2 (OH) 6 ]OH by terephthalate anion

  17. Wild soybean roots depend on specific transcription factors and oxidation reduction related genesin response to alkaline stress.

    Science.gov (United States)

    DuanMu, Huizi; Wang, Yang; Bai, Xi; Cheng, Shufei; Deyholos, Michael K; Wong, Gane Ka-Shu; Li, Dan; Zhu, Dan; Li, Ran; Yu, Yang; Cao, Lei; Chen, Chao; Zhu, Yanming

    2015-11-01

    Soil alkalinity is an important environmental problem limiting agricultural productivity. Wild soybean (Glycine soja) shows strong alkaline stress tolerance, so it is an ideal plant candidate for studying the molecular mechanisms of alkaline tolerance and identifying alkaline stress-responsive genes. However, limited information is available about G. soja responses to alkaline stress on a genomic scale. Therefore, in the present study, we used RNA sequencing to compare transcript profiles of G. soja root responses to sodium bicarbonate (NaHCO3) at six time points, and a total of 68,138,478 pairs of clean reads were obtained using the Illumina GAIIX. Expression patterns of 46,404 G. soja genes were profiled in all six samples based on RNA-seq data using Cufflinks software. Then, t12 transcription factors from MYB, WRKY, NAC, bZIP, C2H2, HB, and TIFY families and 12 oxidation reduction related genes were chosen and verified to be induced in response to alkaline stress by using quantitative real-time polymerase chain reaction (qRT-PCR). The GO functional annotation analysis showed that besides "transcriptional regulation" and "oxidation reduction," these genes were involved in a variety of processes, such as "binding" and "response to stress." This is the first comprehensive transcriptome profiling analysis of wild soybean root under alkaline stress by RNA sequencing. Our results highlight changes in the gene expression patterns and identify a set of genes induced by NaHCO3 stress. These findings provide a base for the global analyses of G. soja alkaline stress tolerance mechanisms.

  18. Cyclic, Early Diagenetic Dolomite Formation in Alkaline Lake Van

    Science.gov (United States)

    McCormack, J.; Bontognali, T. R. R.; Immenhauser, A.; Kwiecien, O.

    2017-12-01

    Modern dolomite-forming environments are commonly constrained to evaporitic marine or marginal marine settings such as lagoons and sabkhas. Beside microbial mediation, high temperatures and Mg2+ concentrations in solution are factors considered important in aiding dolomite formation. Accordingly, previous studies associate the presence of dolomite within deep sediments of alkaline Lake Van (Turkey) with periods of enhanced evaporation, low lake levels and high Mg/Ca ratio. We systematically studied dolomite within the sedimentary record of Lake Van by means of XRD, SEM and stable isotope (δ18O and δ13C) mass spectrometry. First, we considered the origin of the dolomite; next, we focused on the wider implication of its presence. SEM imaging documents large dolomite crystals interwoven with clay minerals and individual crystals with different crystallographic orientations grown together, indicating space-limited growth within the sediment. According to recent climatic reconstructions for the same sequence (ICDP PALEOVAN project), the water depth of the coring site - today at 350 m - unlikely fell below 200 m. Consequently, dolomite formed below a thick water column at constantly low temperatures (supported by heavy δ18O signature). Within this environment, variations in Mg/Ca ratio, pH and alkalinity, which are constantly high, have no effect on the episodic nature of dolomite precipitation. These observations call for a re-evaluation of the palaeoenvironments often invoked to interpret intervals rich in dolomite within ancient sedimentary sequences (e.g., periods of enhanced aridity and evaporation). Further, and in contrast to previous interpretations, our dolomite concentration data backed up by ICDP PALEOVAN reconstructions suggest that intervals rich in dolomite coincide with periods of high lake level and increased humidity. High dolomite concentrations (20 - 85 % relative carbonate content) occur cyclically within the last glacial period and coincide with

  19. Chemically durable polymer electrolytes for solid-state alkaline water electrolysis

    Science.gov (United States)

    Park, Eun Joo; Capuano, Christopher B.; Ayers, Katherine E.; Bae, Chulsung

    2018-01-01

    Generation of high purity hydrogen using electrochemical splitting of water is one of the most promising methods for sustainable fuel production. The materials to be used as solid-state electrolytes for alkaline water electrolyzer require high thermochemical stability against hydroxide ion attack in alkaline environment during the operation of electrolysis. In this study, two quaternary ammonium-tethered aromatic polymers were synthesized and investigated for anion exchange membrane (AEM)-based alkaline water electrolyzer. The membranes properties including ion exchange capacity (IEC), water uptake, swelling degree, and anion conductivity were studied. The membranes composed of all C-C bond polymer backbones and flexible side chain terminated by cation head groups exhibited remarkably good chemical stability by maintaining structural integrity in 1 M NaOH solution at 95 °C for 60 days. Initial electrochemical performance and steady-state operation performance were evaluated, and both membranes showed a good stabilization of the cell voltage during the steady-state operation at the constant current density at 200 mA/cm2. Although both membranes in current form require improvement in mechanical stability to afford better durability in electrolysis operation, the next generation AEMs based on this report could lead to potentially viable AEM candidates which can provide high electrolysis performance under alkaline operating condition.

  20. Computer simulation studies of ternary uranate phases with alkali and alkaline-earth metals: Pt. 1

    International Nuclear Information System (INIS)

    Ball, R.G.J.

    1992-01-01

    Solid-state computer simulation techniques have been used to study the alkali and alkaline-earth metal MUO 3 uranate phases. These compounds display an interesting gradation in their structures which, it is shown, is accompanied by a variation in their intrinsic defect chemistry. For example, in the alkali-metal series, LiUO 3 adopts the lithium niobate structure and lithium Frenkel disorder dominates whereas KUO 3 and RbUO 3 adopt regular perovskite structures with Schottky defects being dominant. For the alkaline-earth metal compounds, both the calculations and experiment show that only SrUO 3 and BaUO 3 are stable with respect to the binary oxides. Both of these phases adopt the GdFeO 3 distorted perovskite structure and both have anti-site defects as the dominant intrinsic disorder. The tendency for anti-site disorder is also seen in the oxidation behaviour of these compounds. The calculations suggest that the oxidation will occur through the formation of a secondary UO 2 fluorite phase by the movement of alkaline-earth ions onto uranium sites, leaving behind M vacancies. The calculated energies for such oxidation processes are particularly favourable. The solution of alkaline-earth oxide, M 11 O, in M 11 UO 3 is shown to occur via a mechanism in which the M 11 ions substitute onto both the M 11 and U sublattices. (author)

  1. Ultrasonic synthesis and evaluation of non-platinum catalysts for alkaline direct methanol fuel cells

    Science.gov (United States)

    Bunazawa, Hideaki; Yamazaki, Yohtaro

    Ultrasonic synthesis was investigated as a synthesis method of non-platinum catalysts for alkaline direct methanol fuel cells (alkaline DMFCs) such as 20% mass Pd/C, Au/C, and PdAu/C. Among four kinds of solvents, ethylene glycol was demonstrated to be the optimum solvent for the synthesis of those catalysts. When ethylene glycol was used, the synthesized metal nanoparticles were highly dispersed on carbon particles. The synthesized Pd/C and PdAu/C showed the high oxygen reduction reaction (ORR) activity in alkaline condition (0.5 M NaOH aqueous solution), which was comparable to conventional Pt/C. Moreover, they showed lower methanol oxidation reaction (MOR) activity. Membrane electrode assemblies (MEAs) containing the synthesized Pd/C cathode catalysts and alkaline ion exchange membranes were fabricated and evaluated by single cell tests. They showed high performance that was comparable to MEAs with Pt/C cathode. In addition, it was found that the synthesized Pd/C was relatively tolerant to methanol crossover.

  2. Heparin and alkalinized lidocaine versus alkalinized lidocaine for treatment of interstitial cystitis symptoms.

    Science.gov (United States)

    Parsons, C Lowell; Koziol, James A; Proctor, Jeffrey G; Zupkas, Paul; Argade, Sulabha

    2015-04-01

    Interstitial cystitis (IC), sometimes referred to as IC/bladder pain syndrome, is a substantial health care problem. Once considered a rare, orphan disease, it is now believed to be relatively common. This pilot study was undertaken to determine if the combination of heparin and alkalinized lidocaine (heparin-lidocaine) was more efficacious than alkalinized lidocaine at relieving pain and urgency symptoms associated with IC and also capable of yielding higher lidocaine absorption. A single blind study was conducted on 14 IC patients with a heparin-lidocaine combination versus alkalinized lidocaine instilled intravesically. In a separate study serum lidocaine levels for heparin-alkalinized lidocaine combination versus USP lidocaine only were determined by high performance liquid chromatography. Alkalinized lidocaine and heparin have been reported to provide relief from pain and urgency symptoms associated with IC. The heparin-lidocaine combination significantly reduced the % of bladder pain (38% versus 13%, p = 0.029) and urgency (42% versus 8% p = 0.003) compared to lidocaine. In addition the GAR was significantly better for the heparin-lidocaine combination at both 1 hr % improved (77% versus 50%, p = 0.04) and 24 hrs (57% versus 23%, p = 0.002) after study drug treatment. Serum lidocaine levels for the heparin-lidocaine combination were significantly higher compared to USP lidocaine (unalkalinized). The mean +/- SEM was 0.45 +/- 0.09 µg/mL and 0.20 +/- 0.05 µg/mL, respectively (p = 0.019). In this pilot study the heparin-lidocaine combination results in significantly better relief of IC symptoms compared to alkalinized lidocaine and the combination yields higher lidocaine absorption than USP lidocaine.

  3. Temperature Dependence of Mineral Solubility in Water. Part 2. Alkaline and Alkaline Earth Bromides

    Science.gov (United States)

    Krumgalz, B. S.

    2018-03-01

    Databases of alkaline and alkaline earth bromide solubilities in water at various temperatures were created using experimental data from publications over about the last two centuries. Statistical critical evaluation of the created databases was produced since there were enough independent data sources to justify such evaluation. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed bromide minerals have been calculated at various temperature intervals and also represented by polynomial expressions.

  4. Selective leaching of Zn from spent alkaline batteries using environmentally friendly approaches.

    Science.gov (United States)

    Maryam Sadeghi, S; Vanpeteghem, Guillaumme; Neto, Isabel F F; Soares, Helena M V M

    2017-02-01

    The main aim of this work was to evaluate the possibility of using microwave or ultrasound to assist the efficient and selective leaching of Zn from spent alkaline batteries and compare the results with those obtained using the conventional method. Two different strategies were applied: acid leaching of a washed residue and alkaline leaching of the original residue. In both (acid and alkaline) approaches, the use of microwave- or ultrasound-assisted leaching increased the extraction of Zn compared with the best results obtained using conventional leaching [acid leaching (1.5mol/L H 2 SO 4 , 3h, 80°C), 90% of Zn extracted; alkaline leaching (6mol/L NaOH, 3h, 80°C), 42% of Zn extracted]. With acid leaching, 94% of the Zn was extracted using microwave-assisted leaching (1 cycle, 30s, 1mol/L H 2 SO 4 ), and 92% of the Zn was extracted using ultrasound-assisted leaching (2min, 0.1p, 20% amplitude, 1mol/L H 2 SO 4 ). Ultrasound-assisted leaching resulted in a more selective (Zn/Mn ratio of 5.1) Zn extraction than microwave-assisted leaching (Zn/Mn ratio of 3.5); both processes generated a concentrated Zn solution (⩾18.7g/L) with a purity (83.3% and 77.7%, respectively) that was suitable for electrowinning. With alkaline leaching, microwave- (1 cycle, 3 min, 4mol/L NaOH) and ultrasound-assisted (14min, 0.1p, 20% amplitude, 4mol/L NaOH) leaching extracted about 80% of the Zn and less than 0.01% of the Mn, which resulted in lesser concentrated Zn solutions (approximately 16.5g/L) but with high purity (>99.5%) that was suitable for the recovery of Zn by precipitation. The microwave- and ultrasound-assisted leaching strategies used in this work proved to be efficient and environmentally-friendly approaches for the extraction of Zn from spent alkaline residues since a concentrated Zn solution with adequate purity for subsequent Zn recovery was obtained using significantly decreased leaching times and concentrations of chemicals. Copyright © 2017 Elsevier Ltd. All rights

  5. Persistently increased intestinal fraction of alkaline phosphatase

    DEFF Research Database (Denmark)

    Nathan, E; Baatrup, G; Berg, H

    1984-01-01

    Persistent elevation of the intestinal fraction of the alkaline phosphatase (API) as an isolated finding has to our knowledge not been reported previously. It was found in a boy followed during a period of 5.5 years. The only symptom was transient periodic fatigue observed at home, but not apparent...... during hospitalization. His blood type was O, RH+, Le (a-, b+) and he was a secretor of H-substance, which may be associated with rising API activity after fat-loading. In this case API was unchanged after fat-loading. Neither intestinal nor liver diseases were found, and no other cause for the elevated...

  6. Alkaline carbonates in blast furnace process

    Directory of Open Access Journals (Sweden)

    P. Besta

    2014-10-01

    Full Text Available The production of iron in blast furnaces is a complex of physical, chemical and mechanical processes. The input raw materials contain not only metallic components, but also a number of negative elements. The most important negative elements include alkaline carbonates. They can significantly affect the course of the blast furnace process and thus the overall performance of the furnace. As a result of that, it is essential to accurately monitor the alkali content in the blast furnace raw materials. The article analyzes the alkali content in input and output raw materials and their impact on the blast furnace process.

  7. RES Hydrogen: efficient pressurised alkaline electrolysers

    DEFF Research Database (Denmark)

    Bowen, Jacob R.; Bentzen, Janet Jonna; Jørgensen, Peter Stanley

    The RESelyser project addresses issues associated with coupling alkaline electrolysis to renewable energy sources such as electrode stability and gas purity by implementing improved electrodes and a new separator membrane concept. The project aims to improve performance, operation pressure...... and reduce system cost. The project supports DTU Energy's activities on electrodes within the larger FCH-JU project. The overall project demonstrated: improved electrode efficiency also during cyclic operation, safe gas purity at a system pressure of 30 bar, 10 kW stack operation and estimated system costs...

  8. Exploring Strong Interactions in Proteins with Quantum Chemistry and Examples of Their Applications in Drug Design.

    Directory of Open Access Journals (Sweden)

    Neng-Zhong Xie

    Full Text Available Three strong interactions between amino acid side chains (salt bridge, cation-π, and amide bridge are studied that are stronger than (or comparable to the common hydrogen bond interactions, and play important roles in protein-protein interactions.Quantum chemical methods MP2 and CCSD(T are used in calculations of interaction energies and structural optimizations.The energies of three types of amino acid side chain interactions in gaseous phase and in aqueous solutions are calculated using high level quantum chemical methods and basis sets. Typical examples of amino acid salt bridge, cation-π, and amide bridge interactions are analyzed, including the inhibitor design targeting neuraminidase (NA enzyme of influenza A virus, and the ligand binding interactions in the HCV p7 ion channel. The inhibition mechanism of the M2 proton channel in the influenza A virus is analyzed based on strong amino acid interactions.(1 The salt bridge interactions between acidic amino acids (Glu- and Asp- and alkaline amino acids (Arg+, Lys+ and His+ are the strongest residue-residue interactions. However, this type of interaction may be weakened by solvation effects and broken by lower pH conditions. (2 The cation- interactions between protonated amino acids (Arg+, Lys+ and His+ and aromatic amino acids (Phe, Tyr, Trp and His are 2.5 to 5-fold stronger than common hydrogen bond interactions and are less affected by the solvation environment. (3 The amide bridge interactions between the two amide-containing amino acids (Asn and Gln are three times stronger than hydrogen bond interactions, which are less influenced by the pH of the solution. (4 Ten of the twenty natural amino acids are involved in salt bridge, or cation-, or amide bridge interactions that often play important roles in protein-protein, protein-peptide, protein-ligand, and protein-DNA interactions.

  9. Reactivity of 4'-substituted 2,4-dinitrodiphenyl sulfides and sulfones during alkaline hydrolysis in aqueous dioxane

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A.V.

    1986-01-10

    This paper studies the kinetics of alkaline hydrolysis of 4'-substituted 2,4-dinitrodiphenyl sulfides (I), 2,4-dinitrodiphenyl sulfones (II), and 1-substituted 2,4-dinitrobenzenes (III) in a 40% dioxane-water solution. Analysis of the results obtained are presented and it is shown that in its character, the influence of the substituents in carrying out the alkaline hydrolysis reaction in 40% dioxane for the reaction series (I) obeys the general patterns of activated nucleophilic substitution, with the exception of 2,4-dinitro-4'-methylthiodiphenyl sulfide.

  10. Neutral alkaline-metal and alkaline-earth-metal derivatives of imidazole and benzimidazole.

    Science.gov (United States)

    Blanco, Fernando; Lloyd, David G; Alkorta, Ibon; Elguero, José

    2014-06-12

    A theoretical study of the minima and connecting transition states of the neutral complexes formed by alkaline-metal and alkaline-earth-metal derivatives of imidazolate and benzimidazolate anions has been carried out using B3LYP/6-31+G(d,p), B3LYP/6-311+G(3df,2p), and G3B3 methods. Two and three nondegenerated minima and two and four TS structures have been identified for imidazole and benzimidazole derivatives, respectively. The most stable minima of the alkaline-metal derivatives of both systems correspond to the metal interacting with the imidazole ring, whereas in the alkaline-earth-metal derivatives, the preferred minima depend on the substituent. A remarkable feature of some minima is the fact that some of the metal-aromatic interactions follow the classical π-cation pattern, even though the global structure corresponds to a neutral salt, constituting a class of noncovalent interaction of great interest in the chemistry of aromatic and heterocyclic complexes. A CSD search has confirmed that the two bonding modes, N-σ and π, are present in the solid phase. The π mode has been analyzed by comparison with other azoles.

  11. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H. [Westinghouse Hanford Co., Richland, WA (United States); Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K. [Russian Academy of Sciences (Russian Federation). Inst. of Physical Chemistry

    1995-05-01

    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes.

  12. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    International Nuclear Information System (INIS)

    Delegard, C.H.; Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K.

    1995-05-01

    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes

  13. Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment

    Directory of Open Access Journals (Sweden)

    Chung K.W.

    2015-06-01

    Full Text Available The alkaline treatment of NdFeB powders in NaOH solution at various equivalent amounts of NaOH at 100°C was performed. The resultant powders were then leached in 0.5M H2SO4 solution at 25°C for 2 minutes. At 5 equivalents of NaOH, neodymium in NdFeB powders was partially transformed to neodymium hydroxide. The transformation of neodymium to neodymium hydroxide actually occurred at 10 equivalents of NaOH and was facilitated by increasing the equivalent of NaOH from 10 to 30. In addition, iron was partially transformed to magnetite during the alkaline treatment, which was also promoted at a higher equivalent of NaOH. The leaching yield of neodymium from alkaline-treated powders was increased with an increasing equivalent of NaOH up to 10; however, it slightly decreased with the equivalent NaOH of over 10. The leaching yield of iron was inversely proportional to that of rare earth elements. NdFeB powders treated at 10 equivalents of NaOH showed a maximum leaching yield of neodymium and dysprosium of 91.6% and 94.6%, respectively, and the lowest leaching yield of iron of 24.2%, resulting in the highest selective leaching efficiency of 69.4%.

  14. Seeking effective dyes for a mediated glucose-air alkaline battery/fuel cell

    Science.gov (United States)

    Eustis, Ross; Tsang, Tsz Ming; Yang, Brigham; Scott, Daniel; Liaw, Bor Yann

    2014-02-01

    A significant level of power generation from an abiotic, air breathing, mediated reducing sugar-air alkaline battery/fuel cell has been achieved in our laboratories at room temperature without complicated catalysis or membrane separation in the reaction chamber. Our prior studies suggested that mass transport limitation by the mediator is a limiting factor in power generation. New and effective mediators were sought here to improve charge transfer and power density. Forty-five redox dyes were studied to identify if any can facilitate mass transport in alkaline electrolyte solution; namely, by increasing the solubility and mobility of the dye, and the valence charge carried per molecule. Indigo dyes were studied more closely to understand the complexity involved in mass transport. The viability of water-miscible co-solvents was also explored to understand their effect on solubility and mass transport of the dyes. Using a 2.0 mL solution, 20% methanol by volume, with 100 mM indigo carmine, 1.0 M glucose and 2.5 M sodium hydroxide, the glucose-air alkaline battery/fuel cell attained 8 mA cm-2 at short-circuit and 800 μW cm-2 at the maximum power point. This work shall aid future optimization of mediated charge transfer mechanism in batteries or fuel cells.

  15. Spectroscopic characterization of alkaline earth uranyl carbonates

    International Nuclear Information System (INIS)

    Amayri, Samer; Reich, Tobias; Arnold, Thuro; Geipel, Gerhard; Bernhard, Gert

    2005-01-01

    A series of alkaline uranyl carbonates, M[UO 2 (CO 3 ) 3 ].nH 2 O (M=Mg 2 , Ca 2 , Sr 2 , Ba 2 , Na 2 Ca, and CaMg) was synthesized and characterized by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after nitric acid digestion, X-ray powder diffraction (XRD), and thermal analysis (TGA/DTA). The molecular structure of these compounds was characterized by extended X-ray absorption fine-structure (EXAFS) spectroscopy and X-ray photoelectron spectroscopy (XPS). Crystalline Ba 2 [UO 2 (CO 3 ) 3 ].6H 2 O was obtained for the first time. The EXAFS analysis showed that this compound consists of (UO 2 )(CO 3 ) 3 clusters similar to the other alkaline earth uranyl carbonates. The average U-Ba distance is 3.90+/-0.02A.Fluorescence wavelengths and life times were measured using time-resolved laser-induced fluorescence spectroscopy (TRLFS). The U-O bond distances determined by EXAFS, TRLFS, XPS, and Raman spectroscopy agree within the experimental uncertainties. The spectroscopic signatures observed could be useful for identifying uranyl carbonate species adsorbed on mineral surfaces

  16. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  17. Strong coupling analogue of the Born series

    International Nuclear Information System (INIS)

    Dolinszky, T.

    1989-10-01

    In a given partial wave, the strength of the centrifugal term to be incorporated into the WKBA solutions in different spatial regions can be adjusted so as to make the first order wave functions everywhere smooth and, in strong coupling, exactly reproduce Quantum Mechanics throughout the space. The relevant higher order approximations supply an absolute convergent series expansion of the exact scattering state. (author) 4 refs.; 2 figs.; 2 tabs

  18. General strongly nonlinear variational inequalities

    International Nuclear Information System (INIS)

    Siddiqi, A.H.; Ansari, Q.H.

    1990-07-01

    In this paper we develop iterative algorithms for finding approximate solutions for new classes of variational and quasi-variational inequalities which include, as special case, some known results in this field. It is shown that the solutions of the iterative schemes converge to the exact solutions. (author). 15 refs

  19. LEACHING OF URANIUM ORES USING ALKALINE CARBONATES AND BICARBONATES AT ATMOSPHERIC PRESSURE

    Science.gov (United States)

    Thunaes, A.; Brown, E.A.; Rabbits, A.T.; Simard, R.; Herbst, H.J.

    1961-07-18

    A method of leaching uranium ores containing sulfides is described. The method consists of adding a leach solution containing alkaline carbonate and alkaline bicarbonate to the ore to form a slurry, passing the slurry through a series of agitators, passing an oxygen containing gas through the slurry in the last agitator in the series, passing the same gas enriched with carbon dioxide formed by the decomposition of bicarbonates in the slurry through the penultimate agitator and in the same manner passing the same gas increasingly enriched with carbon dioxide through the other agitators in the series. The conditions of agitation is such that the extraction of the uranium content will be substantially complete before the slurry reaches the last agitator.

  20. Development of alkaline/surfactant/polymer (ASP flooding technology for recovery of Karazhanbas oil

    Directory of Open Access Journals (Sweden)

    Birzhan Zhappasbaev

    2016-03-01

    Full Text Available The tertiary oil recovery methods like alkaline, surfactant and polymer (ASP flooding are very perspective in order to achieve the synergetic effect out of the different impacts which are caused by these chemicals, which affect oil and water filtration in the reservoir and increase oil recovery. In this communication, we consider the applicability of hydrophobically modified polyampholyte – poly(hexadecylaminocrotonatebetaine (PHDACB as ASP flooding agent for recovery of oil from Karazhanbas oilfield. As “polysoap”, the aqueous solution of PHDACB dissolved in aqueous KOH was used. This system combines the advantages of alkaline, surfactant and polymer and exhibits the synergistic effect. The laboratory results showed that the ASP flooding considerably increases the oil recovery in addition to water flooding. In perspective, the ASP flooding may substitute the steam injection and other thermal enhanced oil recovery (EOR technologies.