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Sample records for alkaline medium peliculas

  1. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    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.)

  2. Extraction of uranium from alkaline medium by certain amines

    International Nuclear Information System (INIS)

    A possible route for treatment of irradiated uranium from alkaline solution was recently addressed. This may have some advantages related to the isolation of many troublesome fission products upon alkaline dissolution of uranium oxides. In this work, the solubility of uranium oxides in alkaline medium of sodium carbonate and sodium hydroxide mixture was investigated. The different factors affecting the solubility were studied. From alkaline solutions, the extraction of uranium by different amines was carried out. The equilibrium encountered in this extraction systems was elaborated. Possible use of these systems for treatment of irradiated uranium was discussed

  3. Kraft lignin behavior during reaction in an alkaline medium

    International Nuclear Information System (INIS)

    The reaction of kraft lignin in an alkaline medium was studied using a microreactor set. Chemical changes in reacted kraft lignins that include ash content, Klason lignin, acid-soluble lignin and sugars were studied. Structural characteristics of these lignins were also determined in terms of phenolic-hydroxyl, aliphatic-hydroxyl, methoxyl, Mw, Mn and polydispersity. The techniques employed were HPLC, UV spectroscopy, FTIR spectroscopy, proton nuclear magnetic resonance spectroscopy and organic gel permeation chromatography (GPC). The effects of temperature and reaction time on lignin properties were studied using response surface methodology. The reaction temperature ranged from 116 to 180 oC and the reaction time ranged from 18 to 103 min. The obtained response surfaces show that both factors affected lignin properties within these ranges. The phenolic and aliphatic-hydroxyl content and the number of active sites increased when the treatment severity was increased. Weight-average molecular weight (Mw), number-average molecular weight (Mn) and solid-yield percentage decreased when the treatment severity was increased. -- Highlights: → We studied the chemical and structural changes of Kraft lignin during its reaction in alkaline medium. → The phenolic and aliphatic hydroxyl content and the number of active sites increased when the treatment severity was increased. → Weight-average MW, number-average MW and solid-yield percentage decreased when the treatment severity was increased.

  4. Mechanism of Oxidation of L-Histidine by Heptavalent Manganese in Alkaline Medium

    OpenAIRE

    Jose, Timy P.; Nandibewoor, Sharanappa T.; Suresh M. Tuwar

    2005-01-01

    The kinetics of oxidation of L-histidine by manganese(VII) in aqueous alkaline medium at a constant ionic strength of 0.05 mol dm-3 was studied spectrophotometrically. The reaction between permanganate and L-histidine in alkaline medium exhibits 2:1 stoichiometry (KMnO4: L-histidine). The reaction is of first order in [KMnO4], less than unit order in [L-histidine] and [alkali]. Decrease in the dielectric constant of the medium decreases the rate of reaction. Effect of added products and ionic...

  5. Mechanistic Investigation of Oxidation of Phenylpropanolamine with N-Bromobenzenesulfonamide in Alkaline Medium: A Kinetic Approach

    OpenAIRE

    Prasad, Ningegowda; Mohana, Kikkeri N.

    2008-01-01

    The kinetics of oxidation of phenylpropanolamine (PPA) with sodium N-bromobenzenesulfonamide or bromamine-B (BAB) has been investigated in alkaline medium at 308 K. The oxidation reaction obeys the rate law, – d[BAB]/dt = k [BAB] [PPA]x [OH-], where x is less than unity. The variation of ionic strength of the medium, addition of the reduction product, benzenesulfonamide, and chloride ion had no pronounced effect on the reaction rate. Decrease of dielectric permittivity of the medium by increa...

  6. Study on polyester fabric using polyvinyl alcohol in alkaline medium to enhance the hydrophilic character

    Directory of Open Access Journals (Sweden)

    S. PITCHAI

    2014-09-01

    Full Text Available Polyester (PET fabric was treated with polyvinyl alcohol (PVA in alkaline medium. The moisture regain, water retention and wickability of the PVA treated polyester fabric were tested. The presence of PVA in the treated PET fabric was assessed by spot test. The treated fabric was also characterized by scanning electron microscope (SEM. The PVA treated polyester fabric showed improved hydrophilic character over intact and sodium hydroxide treated PET fabrics.

  7. Spectroscopic and mechanistic investigations into oxidation of aspartame by diperiodatocuprate(III in aqueous alkaline medium

    Directory of Open Access Journals (Sweden)

    Jayant I. Gowda

    2015-12-01

    Full Text Available The oxidation of aspartame (ASP by diperiodatocuprate(III (DPC in aqueous alkaline medium at 298 K and a constant ionic strength of 0.30 mol dm−3 was studied spectrophotometrically. The reaction between aspartame and diperiodatocuprate(III in alkaline medium exhibits 1:6 stoichiometry in the reaction. The order of the reaction with respect to [diperiodatocuprate(III] was unity, while the apparent order with respect to [aspartame] was less than unity over the concentration range studied. The rate of the reaction increased with increase in [OH−] whereas the rate decreased with increase in [$ {\\text{IO}}^-_4 $]. Increasing the ionic strength of the medium increased the rate. The main products were identified by FT-IR, NMR, and LC-MS spectral studies. The probable mechanism was proposed. The activation parameters with respect to slow step of the mechanism were computed and discussed. Thermodynamic quantities were also calculated. Kinetic studies suggest that [Cu(H2IO6(H2O2] is the reactive species of Cu(III.

  8. Kinetics and Mechanism of Oxidation of Ethylene Glycol Monoethylether by Diperiodatonickelate(IV) in Alkaline Medium

    Institute of Scientific and Technical Information of China (English)

    单金缓; 魏海英; 申世刚; 孙汉文

    2003-01-01

    The kinetics of oxidation of ethylene glycol monoethylether (EGE) by diperiodatonickelate(IV) ion (DPN) was studied by spectrophotometry in alkaline medium. The reaction rate showed first order dependence on Ni(IV) and positive fractional order with respect to EGE. The pseudo-first order rate conslants, kobs increased with the increase of [OH-] and decreased with the increase of [IO4- ]. Added salts had little effect on the rate and no free radical was detected. Based on these,the mechanism including the equilibrium between DPN and EGE was proposed. Furthermore, the activation parameters of the reaction were calculated.

  9. Kinetics and Mechanistic Study of Permanganate Oxidation of Fluorenone Hydrazone in Alkaline Medium

    OpenAIRE

    Fawzy, Ahmed; Saleh A. Ahmed; Althagafi, Ismail I.; Morad, Moataz H.; Khairou, Khalid S

    2016-01-01

    The oxidation kinetics of fluorenone hydrazone (FH) using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was...

  10. Degradability of coconut fibre coated with polystyrene in an alkaline medium=Degradability of coconut fibre coated with polystyrene in an alkaline medium

    Directory of Open Access Journals (Sweden)

    Fermin Garcia Velasco

    2016-02-01

    Full Text Available The surface of plant fibre consists mainly of compounds such as cellulose, hemicellulose, lignin, pectin and extractives. These organic compounds are sensitive to the action of many chemical agents and to basic pH, which hinders their use in cementitious composites to make them more sustainable. The aim of this work was to evaluate the efficiency of polystyrene (0, 1, 3 and 5%, plus 3% and heat treatment at 140°C on the protection of coconut fibre in an alkaline medium. The fibres were submersed in an alkaline solution (pH 14 for a total of 63 days, and were periodically evaluated by gravimetric analysis. At the end of the test, the fibres were analysed by scanning electron microscopy. According to the analysis, the sample of coconut fibre with no protective coating lost 80% of its initial weight and, through scanning electron microscopy, it was possible to see the destruction of the surface structure of the fibre, exposing the beams of cellulose microfibres located in the inner regions. The coconut fibres with a 3% polystyrene coating together with heat treatment ended the test with a percentage final weight greater than 50% of the initial weight. A polystyrene coating (3% followed by heat treatment at 140°C improved durability in the coconut fibres by approximately 30%, when immersed in an alkaline medium. =A superfície da fibra vegetal é constituída principalmente por compostos como celulose, hemicelulose, lignina, pectina e extrativos. Esses compostos orgânicos são sensíveis à ação de muitos agentes químicos e ao pH básico, o que dificulta seu emprego em compósitos cimentícios para torná-los mais sustentáveis. Objetivou-se com este trabalho avaliar a eficiência do poliestireno (0, 1, 3 , 5% e 3% mais tratamento térmico a 140 °C na proteção da fibra de coco em meio alcalino. As fibras ficaram imersas em solução alcalina (pH 14 em um total de 63 dias e foram avaliadas periodicamente por meio de ensaio gravimétrico. Ao

  11. Anodic oxidation of ethylenediaminetetraacetic acid on platinum electrode in alkaline medium

    International Nuclear Information System (INIS)

    Ethylenediaminetetraacetic acid (EDTA) forms strong metal complexes and is often used to remove scale from heat-transfer equipment and to decontaminate equipment exposed to radioactive material. However, the resultant waste in the form of EDTA-metal complex is hard to treat due to the high stability of such complexes. The anodic oxidation of ethylenediaminetetraacetic acid (EDTA) was studied in alkaline medium on a smooth platinum electrode. Bulk electrolysis indicated that stable organic intermediates (formaldehyde and glyoxal) are formed during the oxidation of EDTA and that complete oxidation to CO2 can be achieved. The proposed pathway suggests that the acetate groups in EDTA are initially oxidized, generating formaldehyde and ethylenediamine. The rest potential of EDTA (0.066 to 0.164 V vs. Hg/HgO) was observed to be higher than for other organic species. In alkaline medium, very little EDTA oxidation was found to occur on bare platinum. Limiting-current behavior due to PtO formation was observed immediately positive of the rest potential. Tafel behavior (Tafel slope 120 mV/dec) was observed in the potential region positive of the cessation of the bulk of oxide film formation and negative of the onset of O2 evolution. The reaction order of EDTA was determined to be ∼0.5, and that of OH- was close to zero. The reaction mechanism consistent with the experimental data involves Temkin-type adsorption and a first-electron-transfer rate-determining step

  12. Electrocatalytic Oxidation of Cellulose to Gluconate on Carbon Aerogel Supported Gold Nanoparticles Anode in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Hanshuang Xiao

    2015-12-01

    Full Text Available The development of high efficient and low energy consumption approaches for the transformation of cellulose is of high significance for a sustainable production of high value-added feedstocks. Herein, electrocatalytic oxidation technique was employed for the selective conversion of cellulose to gluconate in alkaline medium by using concentrated HNO3 pretreated carbon aerogel (CA supported Au nanoparticles as anode. Results show that a high gluconate yield of 67.8% and sum salts yield of 88.9% can be obtained after 18 h of electrolysis. The high conversion of cellulose and high selectivity to gluconate could be attributed to the good dissolution of cellulose in NaOH solution which promotes its hydrolysis, the surface oxidized CA support and Au nanoparticles catalyst which possesses high amount of active sites. Moreover, the bubbled air also plays important role in the enhancement of cellulose electrocatalytic conversion efficiency. Lastly, a probable mechanism for electrocatalytic oxidation of cellulose to gluconate in alkaline medium was also proposed.

  13. Extracellular expression of alkaline phytase in Pichia pastoris: Influence of signal peptides, promoters and growth medium

    Directory of Open Access Journals (Sweden)

    Mimi Yang

    2015-06-01

    Full Text Available Alkaline phytase isolated from pollen grains of Lilium longiflorum (LlALP possesses unique catalytic and thermal stability properties that suggest it has the potential to be used as a feed supplement. However, substantial amounts of active enzymes are needed for animal feed studies and endogenous levels of LlALP in lily pollen are too low to provide the required amounts. Active rLlALP2 (coded by LlAlp2, one of two isoforms of alkaline phytase cDNA identified in lily pollen has been successfully expressed in intracellular compartments of Pichia pastoris, however enzyme yields have been modest (25–30 mg/L and purification of the enzyme has been challenging. Expression of foreign proteins to the extracellular medium of P. pastoris greatly simplifies protein purification because low levels of endogenous proteins are secreted by the yeast. In this paper, we first describe the generation of P. pastoris strains that will secrete rLlALP2 to the extracellular medium. Data presented here indicates that deletion of native signal peptides at the N- and C-termini of rLlALP2 enhanced α-mating factor (α-MF-driven secretion by four-fold; chicken egg white lysozyme signal peptide was ineffective in the extracellular secretion of rLlALP2. Second, we describe our efforts to increase expression levels by employing a constitutive promoter from the glyceraldehyde-3-phosphate dehydrogenase gene (PGAP in place of the strong, tightly controlled promoter of alcohol oxidase 1 gene (PAOX1. PGAP enhanced the extracellular expression levels of rLlALP2 compared to PAOX1. Finally, we report on the optimization of the culture medium to enhance yields of rLlALP2. The strength of PGAP varies depending on the carbon source available for cell growth; secreted expression of rLlALP2 was highest when glycerol was the carbon source. The addition of histidine and Triton X-100 also enhanced extracellular expression. Taken together, the employment of PGAP under optimized culture

  14. Sulfur-doped carbon nanotubes as catalysts for the oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Based on the unique electronic properties and high surface area of carbon nanotubes as well as the similar electronegativity of sulfur and carbon, a novel electrocatalyst for the oxygen reduction reaction (ORR) was fabricated by directly annealing oxidized carbon nanotubes and p-benzenedithiol in nitrogen. The structural and chemical properties of the resulting sulfur-doped carbon nanotubes (pSCNTs) were investigated using transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The catalytic activity of the pSCNTs towards ORR in alkaline medium was evaluated using rotating ring disk electrode voltammetry. The as-synthesized pSCNT-900 (annealed at 900 °C) exhibits excellent electrochemical performance towards ORR with an onset potential of –0.082 V (vs Ag/AgCl), a high kinetic current density of 34.6 mA cm−2 at –0.35 V), a dominant four-electron transfer mechanism (n = 3.71 at –0.35 V), as well as excellent methanol tolerance and durability. The results obtained are significant for the development of S-doped carbon-based catalysts for alkaline fuel cells

  15. Kinetics and Mechanism of Oxidation of Lactic Acid by Dihydroxyditelluratoargentate(Ⅲ)in Alkaline Medium

    Institute of Scientific and Technical Information of China (English)

    SHANJin-huan; WANGLi; LIUBao-sheng; SHENShi-gang

    2003-01-01

    The kinetics of the oxidation of lactic acid(Lac) by dihydroxyditelluratoargentate(Ⅲ)[abbreviated as DDA of Ag(Ⅲ)]anions was studied in an aqueous alkaline medium by conventional spectrophotometry in a temperature range of 25-40℃.The order of the redox reaction of lactic acid and DDA was found to be first-order.The rates increased with the increase in [OH-]and decreased with the increase in [tellurate].No free radical was detected.In the view of this the dihydroxymonotelluratoargentate(Ⅲ)species(DMA) is assumed to be the active species.A plausible mechanism involving a two-electron transfer is proposed,and the rate equation derived from the mechanism can be used to explain all the experimenttal results.The activation parameters(25℃)and the rate constants of the rate-determining step along with the preequilibrium constants at different temperatures were evaluated.

  16. Kinetics and Mechanism of Oxidation of Lactic Acid by Dihydroxyditelluratoargentate(Ⅲ) in Alkaline Medium

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The kinetics of the oxidation of lactic acid(Lac) by dihydroxyditelluratoargentate(Ⅲ)[abbreviated as DDA of Ag(Ⅲ)] anions was studied in an aqueous alkaline medium by conventional spectrophotometry in a temperature range of 25—40 ℃. The order of the redox reaction of lactic acid and DDA was found to be first-order. The rates increased with the increase in [OH-] and decreased with the increase in [tellurate]. No free radical was detected. In the view of this the dihydroxymonotelluratoargentate(Ⅲ) species(DMA) is assumed to be the active species. A plausible mechanism involving a two-electron transfer is proposed, and the rate equation derived from the mechanism can be used to explain all the experimental results. The activation parameters(25 ℃) and the rate constants of the rate-determining step along with the preequilibrium constants at different temperatures were evaluated.

  17. Palladium and Tin Alloyed Catalysts for the Ethanol Oxidation Reaction in an Alkaline Medium

    Energy Technology Data Exchange (ETDEWEB)

    Su D.; Du W.; Mackenzie K.E.; Milano D.F.; Deskins N.A.; Teng X.

    2012-02-01

    In this paper, we present a study of a series of carbon-supported Pd-Sn binary alloyed catalysts prepared through a modified Polyol method as anode electrocatalysts for direct ethanol fuel cell reactions in an alkaline medium. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and aberration-corrected scanning transmission electron microscopy equipped with electron energy loss spectroscopy were used to characterize the Pd-Sn/C catalysts, where homogeneous Pd-Sn alloys were determined to be present with the surface Sn being partially oxidized. Among various Pd-Sn catalysts, Pd{sub 86}Sn{sub 14}/C catalysts showed much enhanced current densities in cyclic voltammetric and chronoamperometric measurements, compared to commercial Pd/C (Johnson Matthey). The overall rate law of ethanol oxidation reaction for both Pd{sub 86}Sn{sub 14}/C and commercial Pd/C were also determined, which clearly showed that Pd{sub 86}Sn{sub 14}/C was more favorable in high ethanol concentration and/or high pH environment. Density functional theory calculations also confirmed Pd-Sn alloy structures would result in lower reaction energies for the dehydrogenation of ethanol, compared to the pure Pd crystal.

  18. Kinetics and Mechanistic Study of Permanganate Oxidation of Fluorenone Hydrazone in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Ahmed Fawzy

    2016-01-01

    Full Text Available The oxidation kinetics of fluorenone hydrazone (FH using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was illustrated which involves formation of 1 : 1 intermediate complex between fluorenone hydrazones and the active species of permanganate. 9H-Fluorenone as the corresponding ketone was found to be the final oxidation product of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy. The expression rate law for the oxidation reaction was deduced. The reaction constants and mechanism have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants, have been calculated and discussed.

  19. Application of response surface methodology to optimize medium components for production of alkaline protease by bacillus subtilis IC-5

    International Nuclear Information System (INIS)

    Optimization of fermentation medium for production of alkaline protease by using Bacillus subtilis IC-5 was carried out. The concentration of agricultural by product (soybean meal). carbon source (glucose) and nitrogen source (sodium nitrate) were selected for optimization. A central composite design and response surface methodology were used in designing of experiment and statistical analysis of results. This procedure limited the number of actual experiments to 20 and allowed for possible interaction between the three ingredients. The optimum concentrations of the ingredients (g/l) were soybean meal 1.80 glucose 2.11 and sodium nitrate 0.29 were predicted for production of 3468.98 units per ml alkaline protease by Bacillus IC-5. The verification run confirm the predicted optimized concentration of all the three ingredients for maximum production of alkaline protease. These studies successfully demonstrated the use of central composite experimental design for the determination of optimum nutrient concentrations for maximum production of alkaline protease. Results also revealed that smaller and less time consuming experimental designs could be sufficient for fermentation processes. (author)

  20. Thermodynamic, kinetic and mechanistic investigations of Piperazine oxidation by Diperiodatocuprate(III) complex in aqueous alkaline medium

    Indian Academy of Sciences (India)

    Vijay P Pattar; Prashant A Magdum; Deepa G Patil; Sharanappa T Nandibewoor

    2016-03-01

    The kinetics of oxidation of piperazine by the copper complex, diperiodatocuprate(III) in alkaline medium was studied at 298 K, at an ionic strength of 2.0*10-2 mol dm-3. The reaction between piperazine and diperiodatocuprate(III) in aqueous alkaline medium exhibited 1:2 stoichiometry. The oxidation products were identified by UV-Visible, GC-MS and IR spectral studies. In the present study we have obtained different kinetic observations. The reaction exhibited unit order in case of diperiodatocuprate(III), while less than unit order with respect to piperazine. The addition of alkali and periodate retarded the rate of reaction. The effects of added products, ionic strength and dielectric constant on the rate of the reaction were also studied. The active species of diperiodatocuprate(III) in alkaline media is [Cu(OH)2(H3IO6)]-. The activation parameters with respect to the rate determining step and the thermodynamic quantities with respect to the equilibrium steps were evaluated and discussed. The plausible mechanism consistent with the experimental results was proposed and discussed in detail.

  1. Extracellular expression of alkaline phytase in Pichia pastoris: Influence of signal peptides, promoters and growth medium

    OpenAIRE

    Mimi Yang; Sasha Teymorian; Philip Olivares; Pushpalatha P.N. Murthy

    2015-01-01

    Alkaline phytase isolated from pollen grains of Lilium longiflorum (LlALP) possesses unique catalytic and thermal stability properties that suggest it has the potential to be used as a feed supplement. However, substantial amounts of active enzymes are needed for animal feed studies and endogenous levels of LlALP in lily pollen are too low to provide the required amounts. Active rLlALP2 (coded by LlAlp2, one of two isoforms of alkaline phytase cDNA identified in lily pollen) has been successf...

  2. Preparation and characterization of electrocatalysts based on palladium for electro-oxidation of alcohols in alkaline medium

    International Nuclear Information System (INIS)

    In this study Pd/C, Au/C, PdAu/C, PdAuPt/C, PdAuBi/C and PdAuIr/C electrocatalysts were prepared by the sodium borohydride reduction method for the electrochemical oxidation of methanol, ethanol and ethylene glycol. This methodology consists in mix an alkaline solution of sodium borohydride to a mixture containing water/isopropyl alcohol, metallic precursors and the Vulcan XC 72 carbon support. The electrocatalysts were characterized by energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry. The electrochemical oxidation of the alcohols was studied by chronoamperometry using a thin porous coating technique. The mechanism of ethanol electro-oxidation was studied by Fourier Transformed Infrared (FTIR) in situ. The most effective electrocatalysts were tested in alkaline single cells directly fed with methanol, ethanol or ethylene glycol. Preliminary studies showed that the most suitable atomic composition for preparing the ternary catalysts is 50:45:05. Electrochemical data in alkaline medium show that the electrocatalysts PdAuPt/C (50:45:05) showed the better activity for methanol electro oxidation, while PdAuIr/C was the most active for ethanol oxidation and PdAuBi/C (50:45:05) was the most effective for ethylene glycol oxidation in alkaline medium. These results show that the addition of gold in the composition of electrocatalysts increases their catalytic activities. The spectroelectrochemical FTIR in situ data permitted to conclude that C-C bond is not broken and the acetate is formed. (author)

  3. A Kinetically Mechanistic Investigation of Oxidation of 1,4-Butanediamine by Ag(Ⅲ)Complex in Alkaline Medium

    Institute of Scientific and Technical Information of China (English)

    SONG,Changying; SHAN,Jinhuan; Shen,Shigang; Sun,Hanwen

    2009-01-01

    Kinetics and mechanism of oxidation of 1,4-butanediamine by a Ag (Ⅲ)complex were studied spectropho-tometrically in alkaline medium at constant ion strength. The reaction shows first order with respect to the Ag(Ⅲ)complex and 1,4.butanediamine respectively. The second order rate constant,k`:increased with the increasing in[OH-],and decreased with the increasing in[IO4-4].A plausible mechanism was proposed from the kinetics study.The rate equations derived from the mechanism Can explain all experimental phenomena. The activation parameters were calculated.

  4. Stimulatory effect of medium ingredients on alkaline protease production by bacillus licheniformis N-2 and compatibility studies with commercial detergents

    International Nuclear Information System (INIS)

    Suitable concentration of ingredients of the growth medium played a vital role in production of alkaline protease by Bacillus licheniformis. Maximum enzyme activity (875.05 PU/ml) was achieved when the bacterium was grown in the medium containing glucose (1%), soybean meal (1%), K/sub 2/ HPO/sub 4/ (0.5%), MgSO/sub 4/ 7H/sub 2/O (0.05%), NaCI (0.05%), CaCI/sub 2/ 2H/sub 2/O (0.05%) at 37 degree C on 24 h incubation period with agitation of 140 rpm in shake flask cultures. More than 1% glucose decreased the enzyme production. The protease had excellent stability with wide range of Commercial detergents such as Ariel, Bonus, Bright Total, Surf Excel, Wheel and non-branded detergents, recommending its use as an effective additive in detergent formulation. (author)

  5. Cobalt hydroxide film on Pt as co-catalyst for oxidation of polyhydric alcohols in alkaline medium

    International Nuclear Information System (INIS)

    Electrochemical behavior of chemically prepared Co(OH)2 film on Pt has been studied in alkaline medium using cyclic voltammetry and chronoamperometry. Amount of Co(OH)2 deposited increases linearly with the number of times of deposition. The deposit is of fibrous structure, as shown by scanning electron microphotograph. There is evidence of CoII/CoIII and CoIII/CoIV redox transitions during the cyclic potential scan. The former oxidation proceeds under diffusion control. The Co(OH)2 deposit acts as an efficient co-catalyst for anodic oxidation of ethanediol, propanediol and glycerol on Pt in alkaline medium. This is demonstrated by appreciable enhancement of the alcohol oxidation currents upon deposition of Co(OH)2 on Pt. Among the alcohols studied, the highest oxidation currents are obtained for ethanediol, both on Co(OH)2/Pt and bare Pt. Co(OH)2 alone also acts as a redox mediator for alcohol oxidation at more positive potentials.

  6. Mechanistic study of ruthenium (III) catalysed oxidation of L-lysine by diperiodatoargentate (III) in aqueous alkaline medium

    Indian Academy of Sciences (India)

    R R Hosamani; S T Nandibewoor

    2009-05-01

    The kinetics of Ru(III) catalysed oxidation of L-lysine by diperiodatoargentate (III) (DPA) in alkaline medium at 298 K and a constant ionic strength of 0.50 mol dm-3 was studied spectrophotometrically. The oxidation products are aldehyde (5-aminopentanal) and Ag (I). The stoichiometry is i.e. [L-lysine] : [DPA] = 1 : 1. The reaction is of first order in [Ru(III)] and [DPA] and is less than unit order in both [L-lys] and [alkali]. Addition of periodate had a retarding effect on the reaction. The oxidation reaction in alkaline medium has been shown to proceed via a Ru(III)-L-lysine complex, which further reacts with one molecule of monoperiodatoargentate(III) (MPA) in a rate determining step followed by other fast steps to give the products. The main products were identified by spot test, IR, GC-MS studies. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. The active species of catalyst and oxidant have been identified.

  7. Electrocatalytic oxidation of methanol on Ru deposited NiZn catalyst at graphite in alkaline medium

    International Nuclear Information System (INIS)

    The methanol oxidation on C/NiZn-Ru electrode in a 1.00 M KOH and 1.00 M KOH + 1.00 M methanol solutions at different scan rates and temperatures was studied by the cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. The graphite electrode is coated in a nickel–zinc bath by electrodeposition for use as anode materials for methanol oxidation in alkaline solutions. It is etched in a concentrated alkaline solution to produce a porous and electrocatalytic surface suitable for use in the methanol oxidation (C/NiZn). Ruthenium was electrodeposited on a C/NiZn electrode. The surface morphologies and compositions of electrodes were determined by energy dispersive X-ray (EDX) and scanning electron microscopy (SEM). Kinetic parameters of oxidation such as the anodic electron transfer coefficient (αa), cathodic electron transfer coefficient (αc), charge transfer rate constant (ks) and activation energy values were calculated. The effect of methanol concentration on methanol oxidation were also investigated. It was found that the ruthenium electrodeposited electrode showed higher catalytic activity and stability toward methanol oxidation than the C/NiZn electrode

  8. Electrocatalytic properties of Ni-S-Co coating electrode for hydrogen evolution in alkaline medium

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Amorphous Ni-S-Co alloy was prepared by means of chemical electro-deposition method on the foam nickel matrix. The surface morphology and microstructure of Ni-S-Co coatings were studied using SEM and XRD, and the electrochemical properties were tested by electrochemical methods. The results show that the coating has amorphous structure and the particles of the surface are fine with large specific surface area. The Ni-S-Co alloy is more active with lower potential for hydrogen evolution, higher exchange current density and lower activation energy compared with Ni and Ni-S electrode. Its hydrogen evolution reaction(HER) is enhanced, the size of particles of surface decreases and the surface area increases after being activated by KOH alkaline solution.

  9. Stoichiometric C6-oxidation of hyaluronic acid by oxoammonium salt TEMPO⁺Cl⁻ in an aqueous alkaline medium.

    Science.gov (United States)

    Ponedel'kina, Irina Yu; Khaibrakhmanova, Elvira A; Tyumkina, Tatyana V; Romadova, Irina V; Odinokov, Victor N

    2015-10-01

    This paper reports the selective oxidation of hyaluronic acid (HA) by stoichiometric quantity of 2,2,6,6-tetramethylpiperidine-1-oxoammonium chloride (TEMPO(+)) in aqueous alkaline medium. High efficiency of the HA oxidation and quantitative yield of carboxy-HA per starting TEMPO(+), as well as unusual behavior of the oxidation system generating an oxygen upon alkali-induced oxoammonium chloride decomposition are demonstrated. The scheme for HA oxidation involving both TEMPO(+) and oxygen produced upon the TEMPO(+)Cl(-) decomposition and/or air oxygen is proposed. For comparison, the data on stoichiometric oxidation of such substrates as dermatan sulfate, water-soluble potato starch, methyl 2-acetamido-2-deoxy-β-d-glucopyranoside and ethanol are presented. PMID:26076602

  10. Corrosion of ruthenium dioxide based cathodes in alkaline medium caused by reverse currents

    International Nuclear Information System (INIS)

    A reverse current obtained during power shutdowns in industrial processes, such as chlor-alkali production or alkaline water electrolysis, is deleterious for hydrogen evolving ruthenium dioxide (RuO2) based cathodes. It has been observed that RuO2 coatings after a power shutdown, necessary for e.g. maintenance, are severely damaged unless polarization rectifiers are employed. In this work we show why these types of cathodes are sensitive to reverse currents, i.e. anodic currents, after hydrogen evolution. RuO2 coatings deposited on nickel substrates were subjected to different electrochemical treatments such as hydrogen evolution, oxygen evolution, or reverse currents in 8 M NaOH at 90 °C. Polarity inversion was introduced after hydrogen evolution to simulate the effect of reverse currents. Because of chemical interaction with hydrogen, a significant amount of the RuO2 coating was transformed into hydroxylated species during cathodic polarization. Our study shows that these hydroxylated phases are highly sensitive to electrochemical corrosion during anodic polarization after extended hydrogen evolution

  11. Synthesis and electrocatalytic activity of Au/Pt bimetallic nanodendrites for ethanol oxidation in alkaline medium.

    Science.gov (United States)

    Han, Xinyi; Wang, Dawei; Liu, Dong; Huang, Jianshe; You, Tianyan

    2012-02-01

    Gold/Platinum (Au/Pt) bimetallic nanodendrites were successfully synthesized through seeded growth method using preformed Au nanodendrites as seeds and ascorbic acid as reductant. Cyclic voltammograms (CVs) of a series of Au/Pt nanodendrites modified electrodes in 1M KOH solution containing 1M ethanol showed that the electrocatalyst with a molar ratio (Au:Pt) of 3 exhibited the highest peak current density and the lowest onset potential. The peak current density of ethanol electro-oxidation on the Au(3)Pt(1) nanodendrites modified glassy carbon electrode (Au(3)Pt(1) electrode) is about 16, 12.5, and 4.5 times higher than those on the polycrystalline Pt electrode, polycrystalline Au electrode, and Au nanodendrites modified glassy carbon electrode (Au dendrites electrode), respectively. The oxidation peak potential of ethanol electro-oxidation on the Au(3)Pt(1) electrode is about 299 and 276 mV lower than those on the polycrystalline Au electrode and Au dendrites electrode, respectively. These results demonstrated that the Au/Pt bimetallic nanodendrites may find potential application in alkaline direct ethanol fuel cells (ADEFCs). PMID:22071516

  12. Ethanol oxidation on Pd/C promoted with CaSiO3 in alkaline medium

    International Nuclear Information System (INIS)

    Highlights: • Thermal-decomposed CaSiO3 was added to XC-72 carbon black as composite support. • Modified electronic structure of Pd facilitates the detachment of CO from Pd surface. • CaSiO3 enhances proton transfer process and improves dehydrogenation process. • CaSiO3 promotes oxidation removal of CO due to easier OH− adsorption on electrode. • Pd/50CaSiO3/C catalyst shows highest activity and stability for ethanol oxidation. - Abstract: In this paper, CaSiO3 was prepared using a thermal decomposition approach and added to Vulcan XC-72 carbon black as support material. The X-ray diffraction and Transmission electron microscopy results show that the addition of CaSiO3 does not significantly change the particle size and distribution of Pd nanoparticles. The X-ray photoelectron spectroscopy reveals the interaction between Pd and CaSiO3. In addition, the electrochemical CO-striping measurement reveals that the Pd/50CaSiO3/C catalyst exhibits the largest electrochemical active surface and best CO tolerance. Moreover, cyclic voltammetry and chronoamperometry tests demonstrate that the Pd supported by CaSiO3 and C (50:50 in wt.%) possesses a much higher current density (1408 mA mg−1) than that of the Pd/C catalyst (743 mA mg−1) towards ethanol oxidation in alkaline media, and better stability as well. These results support the suitability of Pd/50CaSiO3/C catalyst developed in this work as a promising candidate for direct ethanol fuel cells application

  13. Nanoporous nickel-copper-phosphorus amorphous alloy film for methanol electro-oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Highlights: • Novel Ni-Cu-P amorphous alloy with nanoporous structure was fabricated by LSV etching. • Lower onset oxidation potential of methanol at NP-NiCuP than both S-NiCuP and NP-NiCu. • Superior activity and stability for methanol oxidation at the NP-NiCuP electrode. • Long lifetime of the NP-NiCuP electrode. - Abstract: Nanoporous Ni-Cu-P amorphous alloy (NP-NiCuP) and nanoporous Ni-Cu crystalline alloy (NP-NiCu) are prepared by the linear sweep voltammetry (LSV) etching of copper from the electroless Ni-Cu-P and Ni-Cu alloy coatings, respectively. The results of X-ray diffraction (XRD) analysis show that the nanoporous Ni-Cu-P alloy is amorphous structure. The scanning electron microscopy (SEM) analysis demonstrates the NP-NiCuP shows a 3-D bi-continuous porous structure with the pore size of 150–200 nm and the ligament size of around 100 nm. Electrochemical performances are measured by cyclic voltammetry (CV) and chronoamperometry (CA). The results prove that the NP-NiCuP electrode exhibits higher the proton diffusion coefficient (D0) of Ni(OH)2 and surface coverage (Γ*) of the redox species than those on smooth electroless Ni-Cu-P amorphous alloy (S-NiCuP) and NP-NiCu electrodes in alkaline solution obviously. Moreover, electro-oxidation of methanol suggests that the NP-NiCuP electrode holds higher anodic current density and lower onset potential than the S-NiCuP and NP-NiCu electrodes. Finally, the NP-NiCuP electrode has stable redox behavior and superior catalytic stability for methanol oxidation

  14. The influence of platinum(IV) ions on the formation of iron oxides in a highly alkaline medium

    Science.gov (United States)

    Krehula, Stjepko; Musić, Svetozar

    2011-05-01

    The effect of the presence of platinum(IV) ions, in the form of Pt(OH)62- at a high pH, on the formation of iron oxides in a highly alkaline precipitation system was investigated using X-ray powder diffraction (XRD), 57Fe Mössbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Monodispersed lath-like α-FeOOH (goethite) particles precipitated by hydrothermal treatment in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material. In the presence of 1 or 5 mol% of platinum ions in the precipitation system the lath-like α-FeOOH particles were formed as a single phase after a short hydrothermal treatment (2 h). No significant change in the size and shape of these particles in comparison to the reference sample was observed. After 6 h of autoclaving the formation of platinum nanoparticles at the surface of α-FeOOH particles via reduction by TMAH and/or its decomposition products became visible. These nanoparticles acted as a catalyst for the reduction of Fe(III) ions into Fe(II) and gradual transformation of α-FeOOH into a mixed Fe(II)-Fe(III) oxide (Fe 3O 4, magnetite) by the dissolution-recrystallization mechanism. The presence of a higher concentration of platinum ions accelerates the process of α-FeOOH → Fe 3O 4 transformation with the appearance of α-Fe 2O 3 (hematite) particles as an intermediate product.

  15. Modification of 1018 carbon steel corrosion process in alkaline sour medium with a formulation of chemical corrosion inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Galicia, Policarpo [Universidad Autonoma Metropolitana - Iztapalapa, Departamento de Quimica, Area de Electroquimica, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico DF (Mexico); Gonzalez, Ignacio [Universidad Autonoma Metropolitana - Iztapalapa, Departamento de Quimica, Area de Electroquimica, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico DF (Mexico)]. E-mail: igm@xanum.uam.mx

    2005-08-10

    This work is focused on researching corrosion mechanism modifications of 1018 carbon steel in alkaline sour medium (0.1 M (NH{sub 4}){sub 2}S and 10 ppm CN{sup -}) using inhibitor formulation (IHF) composed of hydroxyoleic imidazoline (C{sub 12}H{sub 42}ON{sub 2}), HI, and aminoether (C{sub 20}H{sub 28}O{sub 3}N{sub 2}), AE. The accelerated formation of corrosion products was thereby carried out in the presence of the formulation alone and of each of its components separately; these films were subsequently characterized by electrochemical impedance spectroscopy and scanning electron microscopy. The study in the presence of the IHF components revealed that the films formed have different nature, because their physical and chemical properties such as thickness, porosity and (electronic and ionic) conductivity are determined by the media where they are grown. The film formed in the presence of HI has a homogeneous, non-porous topography that impairs the diffusion process of H{sup 0}, in addition, its electronic conductivity is above that observed in the film formed with AE. Then, it was determined that the film formed with IHF presents some distinctive component characteristics which interact in a complementary way improving film passivity.

  16. Optimized electrospinning synthesis of iron-nitrogen-carbon nanofibers for high electrocatalysis of oxygen reduction in alkaline medium

    Science.gov (United States)

    Yan, Xingxu; Liu, Kexi; Wang, Xiangqing; Wang, Tuo; Luo, Jun; Zhu, Jing

    2015-04-01

    To achieve iron-nitrogen-carbon (Fe-N-C) nanofibers with excellent electrocatalysis for replacing high-cost Pt-based catalysts in the cathodes of fuel cells and metal-air batteries, we have investigated and evaluated the effects of polyacrylonitrile (PAN) concentration and the proportion of iron to PAN, along with voltage and flow rate during the electrospinning process, and thus proposed three criteria to optimize these parameters for ideal nanofiber catalysts. The best half-wave potential of an optimized catalysts is 0.82 V versus reversible hydrogen electrode in an alkaline medium, which reaches the best range of the non-precious-metal catalysts reported and is very close to that of commercial Pt/C catalysts. Furthermore, the electron-transfer number of our catalysts is superior to that of the Pt/C, indicating the catalysts undergo a four-electron process. The durability of the optimized Fe-N-C nanofibers is also better than that of the Pt/C, which is attributed to the homogeneous distribution of the active sites in our catalysts.

  17. The Impact of Loading and Temperature on the Oxygen Reduction Reaction at Nitrogen-doped Carbon Nanotubes in Alkaline Medium

    International Nuclear Information System (INIS)

    Highlights: • NCNT loading effect on ORR in alkaline medium. • Temperature effect on ORR at NCNT. • non-linear correlation between temperature and kinetic rate. - Abstract: Metal-free nitrogen-doped carbon nanotube (NCNT) catalysts were synthesised via chemical vapour deposition with ethylenediamine and iron phthalocyanine. The electrochemically active NCNT was studied via thin-film rotating-ring disk voltamogram analysis to elucidate the optimum loading of catalysts for oxygen reduction reaction (ORR) in 0.1 M KOH electrolyte. In this study, the activity and stability of NCNT at elevated temperature were investigated. The current limiting plateau was achieved with loading above 500 μg/cm2 on glassy carbon tip with insignificant change in onset potential (c.a. +0.9 V vs RHE). The highest electron transfer number of 3.90 was obtained and it was found comparable to n = 3.95 on 130 μg/cm2 Pt/C catalysts. The subjection to cell's temperature from 298 K to 343 K showed improved activity and was found stable above 323 K

  18. Three-dimensional nanoporous gold-cobalt oxide electrode for high-performance electroreduction of hydrogen peroxide in alkaline medium

    Science.gov (United States)

    Li, Zhihao; He, Yanghua; Ke, Xi; Gan, Lin; Zhao, Jie; Cui, Guofeng; Wu, Gang

    2015-10-01

    Using a simple hydrothermal method combined with a post-annealing treatment, cobalt oxide (Co3O4) nanosheet arrays are grown on three-dimensional (3D) nanoporous gold (NPG) film supported on Ni foam substrates, in which NPG is fabricated by chemically dealloying electrodeposited Au-Sn alloy films. The morphology and structure of the Co3O4@NPG/Ni foam hybrids are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical activity of the Co3O4@NPG/Ni foam electrode toward hydrogen peroxide electroreduction in alkaline medium is studied by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and chronoamperometry (CA). The results demonstrate that the Co3O4@NPG/Ni foam electrode possesses exceptionally high catalytic activity and excellent stability for the peroxide electroreduction, resulting mainly from the unique electrode architecture. The combined 3D hierarchical porous structures of NPG/Ni foam with the open and porous structures of Co3O4 nanosheet arrays facilitate the mass transport and charge transfer. Therefore, the metal oxides supported on 3D hierarchical porous NPG/Ni foam framework may hold great promise to be effective electrodes for electrocatalytic reduction of peroxide and other electrochemical reactions.

  19. Electroreduction of nitrate ions at a platinum-copper electrode in an alkaline medium: Influence of sodium inositol phytate

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: The electrochemical behavior of a Pt-Cu (copper-platinum) electrode on the electroreduction of nitrate and nitrite ions has been investigated in an alkaline medium (0.05 M NaOH) in the presence of 5 mM sodium inositol phytate (NaIP6). Different electrode materials (Cu, Pt, and Pt-Cu) were used to study their activity and selectivity towards the electroreduction of nitrates and nitrites using cyclic voltammetry. The Pt-Cu electrode shows the best performance. The addition of NaIP6 is to prevent the oxidation of copper atoms to copper ions. The effect of NaIP6 on the optimization of the electrode activity and stability was investigated in this study. The presence of NaIP6 further improves the performance of the Pt-Cu electrode especially the stability of the electrode. The final nitrate and nitrite reduction product is ammonia (NH3) which was observed both in the presence and absence of NaIP6, although different mechanism pathways are assumed to have taken place in both systems

  20. The use of cheap polyaniline and melamine co-modified carbon nanotubes as active and stable catalysts for oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    In this work, an active and stable electrocatalyst for alkaline electrolyte oxygen reduction reaction was prepared by using single-wall carbon nanotubes with high specific surface area as the carbon source, and polyaniline and melamine as dual nitrogen sources via high-temperature pyrolysis process. Electrochemical experiments suggest that the metallic cobalt in the precursor can facilitate the oxygen reduction reaction to be carried out with an efficient 4-electron transfer pathway. Besides, the prepared catalyst has exhibited superior tolerance against methanol crossover effect and outstanding stability compared with commercial Pt-based catalysts in alkaline medium

  1. The effect of iridium(III) ions on the formation of iron oxides in a highly alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Krehula, Stjepko, E-mail: krehul@irb.hr [Division of Materials Chemistry, Ruder Boskovic Institute, PO Box 180, HR-10002 Zagreb (Croatia); Music, Svetozar [Division of Materials Chemistry, Ruder Boskovic Institute, PO Box 180, HR-10002 Zagreb (Croatia)

    2012-03-05

    Highlights: Black-Right-Pointing-Pointer Study of the influence of Ir{sup 3+} ions on the precipitation of iron oxides. Black-Right-Pointing-Pointer Ir{sup 3+} doping in {alpha}-FeOOH caused significant changes in the microstructural properties. Black-Right-Pointing-Pointer Ir{sup 3+} doping in {alpha}-Fe{sub 2}O{sub 3} caused an increase in the Morin transition temperature. Black-Right-Pointing-Pointer Ir{sup 3+} ions caused a phase transformation {alpha}-(Fe,Ir)OOH {yields} {alpha}-(Fe,Ir){sub 2}O{sub 3} {yields} Fe{sub 3}O{sub 4} + Ir{sup 0}. - Abstract: The effect of the presence of Ir{sup 3+} ions on the formation of iron oxides in a highly alkaline precipitation system was investigated using X-ray powder diffraction (XRD), {sup 57}Fe Moessbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Monodispersed lath-like {alpha}-FeOOH (goethite) particles precipitated by hydrothermal treatment in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material. The presence of Ir{sup 3+} ions in the precipitation system strongly influenced the phase composition, magnetic, structural and morphological properties of obtained samples. The formation of {alpha}-Fe{sub 2}O{sub 3} (hematite) along with {alpha}-FeOOH in the first stage of hydrothermal treatment and the transformation of {alpha}-FeOOH and {alpha}-Fe{sub 2}O{sub 3} to Fe{sub 3}O{sub 4} (magnetite) by a longer hydrothermal treatment was caused by the presence of Ir{sup 3+} ions. Ir{sup 3+} for Fe{sup 3+} substitution in the structure of {alpha}-FeOOH brought about changes in unit-cell dimensions, crystallinity, particle size and shape, hyperfine magnetic field and infrared bands positions. Ir{sup 3+} for Fe{sup 3+} substitution in the structure of {alpha}-Fe{sub 2}O{sub 3} led to an increase in the temperature of the Morin transition; Moessbauer spectroscopy showed the presence of

  2. The effect of iridium(III) ions on the formation of iron oxides in a highly alkaline medium

    International Nuclear Information System (INIS)

    Highlights: ► Study of the influence of Ir3+ ions on the precipitation of iron oxides. ► Ir3+ doping in α-FeOOH caused significant changes in the microstructural properties. ► Ir3+ doping in α-Fe2O3 caused an increase in the Morin transition temperature. ► Ir3+ ions caused a phase transformation α-(Fe,Ir)OOH → α-(Fe,Ir)2O3 → Fe3O4 + Ir0. - Abstract: The effect of the presence of Ir3+ ions on the formation of iron oxides in a highly alkaline precipitation system was investigated using X-ray powder diffraction (XRD), 57Fe Mössbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Monodispersed lath-like α-FeOOH (goethite) particles precipitated by hydrothermal treatment in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material. The presence of Ir3+ ions in the precipitation system strongly influenced the phase composition, magnetic, structural and morphological properties of obtained samples. The formation of α-Fe2O3 (hematite) along with α-FeOOH in the first stage of hydrothermal treatment and the transformation of α-FeOOH and α-Fe2O3 to Fe3O4 (magnetite) by a longer hydrothermal treatment was caused by the presence of Ir3+ ions. Ir3+ for Fe3+ substitution in the structure of α-FeOOH brought about changes in unit-cell dimensions, crystallinity, particle size and shape, hyperfine magnetic field and infrared bands positions. Ir3+ for Fe3+ substitution in the structure of α-Fe2O3 led to an increase in the temperature of the Morin transition; Mössbauer spectroscopy showed the presence of α-Fe2O3 in the antiferromagnetically ordered state at 293 K.

  3. Preparation of new titanium nitride-carbon nanocomposites in supercritical benzene and their oxygen reduction activity in alkaline medium

    International Nuclear Information System (INIS)

    Highlights: • TiN/C/graphene composite (SIV) was synthesized using supercritical benzene medium. • SIV catalyst shows high ORR activity due to both TiN and graphene phases. • SIV improves ORR via a mainly 4-electron pathway to form water and around 16% H2O2. • SIV exhibits high stability due to reduce H2O2 and prevent surface poisoning. - Abstract: Titanium nitride-carbon nanocomposites are synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. The as-prepared precursors (SI, SII) are subjected to several heat treatments (SIII–SV). The synthesized nanoparticles are characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The samples are tested as electrocatalyst for oxygen reduction reaction in an alkaline electrolyte. It is shown that the electrocatalytic properties of the synthesized nanoparticles are highly dependent on the heat treatment atmosphere and duration. The heat treatment under ammonia atmosphere at 1000 °C for 10 h (SIV) increased the ORR mass activity from −0.64 (SI) to −1.28 mA mg−1 (SIV) at −0.6 V vs. SCE. Moreover, the heat treated sample (SIV) shows almost twice ORR mass activity as commercial TiN. Rotating disk electrode (RDE) measurements exhibit ORR on commercial TiN proceeds via two parallel pathways including two and four electrons, resulting in almost 60% H2O2 production, while SIV sample improves ORR by reducing H2O2 formation to almost 16%. The high ORR activity and stability of the sample SIV are mainly due to (i) random layer structure of carbon that combines through a hybrid state with TiN nanoparticles, (ii) unstoichiometric nitrogen and oxygen doped into TiN lattice, and (iii) higher electrochemical surface area. Moreover, the possible pathways of carbon phase formation in vicinity of

  4. Accumulation and Reactions of H2O2 during the copper ion Catalyzed Autoxidation of Cysteine in Alkaline Medium

    NARCIS (Netherlands)

    Koningsberger, D.C.; Zwart, J.; Wolput, J.H.M.C. van; Cammen, J.C.J.M. van der

    1981-01-01

    The stoichiometry of the copper catalysed alkaline autoxidation of cysteine has been investigated. Products of this oxidation reaction are cystine, H{2}O{2} and H{2}O. No oxygen containing sulfur acids are produced as long as cysteine is present in the reaction liquid.The H{2}O{2} generated reacts w

  5. Electrochemical behaviour of metal hexacyanoferrate converted to metal hydroxide films immobilized on indium tin oxide electrodes-Catalytic ability towards alcohol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: In this work, we demonstrate a simple method to modify indium tin oxide (ITO) electrodes in order to perform electro-catalytic oxidation of alcohols in alkaline medium. Metal hexacyanoferrate (MHCF) films such as nickel hexacyanoferrate (NiHCF) and copper hexacyanoferrate (CuHCF) were successfully immobilized on ITO electrodes using an electrochemical method. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the structural and morphological aspects of MHCF films. Cyclic voltammetry (CV) was used to study the redox properties and to determine the surface coverage of these films on ITO electrodes. Electrochemical potential cycling was carried out in alkaline medium in order to alter the chemical structure of these films and convert to their corresponding metal hydroxide films. SEM and XPS were performed to analyze the structure and morphology of metal hydroxide modified electrodes. Electro-catalytic oxidation ability of these films towards methanol and ethanol in alkaline medium was investigated using CV. From these studies we found that metal hydroxide modified electrodes show a better catalytic performance and good stability for methanol oxidation along with the alleviation of CO poisoning effect. We have obtained an anodic oxidation current density of ∼82 mA cm-2 for methanol oxidation, which is at least 10 fold higher than that of any metal hydroxide modified electrodes reported till date. The onset potential for methanol oxidation is lowered by ∼200 mV compared to other chemically modified electrodes reported. A plausible mechanism was proposed for the alcohol oxidation based on the redox properties of these modified electrodes. The methodology adapted in this work does not contain costlier noble metals like platinum and ruthenium and is economically viable.

  6. Mechanistic Aspects of Osmium(VIII Catalyzed Oxidation of L-Tryptophan by Diperiodatocuprate(III in Aqueous Alkaline Medium: A Kinetic Model

    Directory of Open Access Journals (Sweden)

    Nagaraj P. Shetti

    2008-01-01

    Full Text Available In presence of osmium(VIII, the reaction between L-tryptophan and diperiodatocuprate(III DPC in alkaline medium exhibits 1:4 stochiometry (L-tryptophan:DPC. The reaction shows first-order dependence on [DPC] and [osmium(VIII], less than unit order in both [L-tryptophan] and [alkali], and negative fractional order in [periodate]. The active species of catalyst and oxidant have been identified. The main products were identified by spectral studies and spot test. The probable mechanism was proposed and discussed.

  7. Inexpensive Ipomoea aquatica Biomass-Modified Carbon Black as an Active Pt-Free Electrocatalyst for Oxygen Reduction Reaction in an Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Yaqiong Zhang

    2015-09-01

    Full Text Available The development of inexpensive and active Pt-free catalysts as an alternative to Pt-based catalysts for oxygen reduction reaction (ORR is an essential prerequisite for fuel cell commercialization. In this paper, we report a strategy for the design of a new Fe–N/C electrocatalyst derived from the co-pyrolysis of Ipomoea aquatica biomass, carbon black (Vulcan XC-72R and FeCl3·6H2O at 900 °C under nitrogen atmosphere. Electrochemical results show that the Fe–N/C catalyst exhibits higher electrocatalytic activity for ORR, longer durability and higher tolerance to methanol compared to a commercial Pt/C catalyst (40 wt % in an alkaline medium. In particular, Fe–N/C presents an onset potential of 0.05 V (vs. Hg/HgO for ORR in an alkaline medium, with an electron transfer number (n of ~3.90, which is close to that of Pt/C. Our results confirm that the catalyst derived from I. aquatica and carbon black is a promising non-noble metal catalyst as an alternative to commercial Pt/C catalysts.

  8. Accumulation and reactions of H2O2 during the copper ion catalysed autoxidation of cysteine in alkaline medium

    OpenAIRE

    Koningsberger, D.C.; De Zwart, J.; Wolput, J.H.M.C. van; Cammen, J.C.J.M. van der

    1981-01-01

    The stoichiometry of the copper catalysed alkaline autoxidation of cysteine has been investigated. Products of this oxidation reaction are cystine, H{2}O{2} and H{2}O. No oxygen containing sulfur acids are produced as long as cysteine is present in the reaction liquid.The H{2}O{2} generated reacts with cysteine selectively to form cystine and H{2}O with r{H}{2}{O}{2} = k{H}{2}{O}{2} [CyS][H{2}O{2}] (k{H}{2}{O}{2} = 0.17 1 mol}-{}1{ s}-{}1{).The reaction between H{2}O{2} and cysteine is not ca...

  9. Wear and chemistry of zirconium-silicate, aluminium-silicate and zirconium-aluminium-silicate glasses in alkaline medium

    International Nuclear Information System (INIS)

    A study of the chemical durability, in alkaline solutions, of zirconium silicate, aluminium silicate, zirconium/aluminium silicate glasses as a function of glass composition is carried out. The glasses were tested using standard DIN-52322 method, where the glass samples are prepared in small polished pieces and attacked for 3 hours in a 800 ml solution of 1N (NaOH + NA2CO3) at 970C. The results show that the presence of ZrO2 in the glass composition increases its chemical durability to alkaline attack. Glasses of the aluminium/zirconium silicate series were melted with and without TiO2. It was shown experimentally that for this series of glasses, the presence of both TiO2 and ZrO2 gave better chemical durability results. However, the best overall results were obtained from the simpler zirconium silicate glasses, where it was possible to make glasses with higher values of ZrO2. (Author)

  10. Kinetics and Mechanism of Oxidation of Triethylene Glycol and Tetraethylene Glycol by Ditelluratoargentate (III in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Jinhuan Shan

    2013-01-01

    Full Text Available The kinetics of oxidation of triethylene glycol and tetraethylene glycol by ditelluratoargentate (III (DTA in alkaline liquids has been studied spectrophotometrically in the temperature range of 293.2 K–313.2 K. The reaction rate showed first-order dependence in DTA and fractional order with respect to triethylene glycol or tetraethylene glycol. It was found that the pseudo-first-order rate constant (kobs increased with an increase in concentration of OH− and a decrease in concentration of H4TeO6 2−. There was a negative salt effect and no free radicals were detected. A plausible mechanism involving a two-electron transfer was proposed, and the rate equations derived from the mechanism explained all the experimental results and observations. The activation parameters along with the rate constants of the rate-determining step were calculated.

  11. Role of Ru(IlI) as an inhibitor in oxidation of lactose by (Cu(bipy)2)2+ in alkaline medium: spectrophotometric and kinetic studies

    International Nuclear Information System (INIS)

    Kinetics of oxidation of lactose by (Cu(bipy)2)2+ in alkaline medium using Ru(III) as an inhibitor has been studied spectrophotometrically at 40 °C. The studies show that the rate of the reaction is zero order with respect to (Cu(bipy)2)2+ and first order with respect to (lactose). The order of reaction is found to be two at low concentrations of OH- (from 1.48×105 to 3.47×105 M) and less than two at its high concentrations (from 4.27×105 to 6.31×105 M). There is a substantial decrease in the pseudo-zero order rate constant with increase in the concentration of Ru(III) chloride, indicating the role of Ru(III) chloride as an inhibitor. Decrease in the rate with increase in dielectric constant of the medium is observed, while ionic strength of the medium and bipyridyl concentration has no influence on the rate. Based on kinetic data and spectrophotometric evidences, a suitable mechanism is proposed for the studied reaction. (author)

  12. Direct, simple derivatization of disulfide bonds in proteins with organic mercury in alkaline medium without any chemical pre-reducing agents

    International Nuclear Information System (INIS)

    Highlights: • A simple procedure for the derivatization of proteins disulfide bonds. • Cysteine groups in several proteins derivatised with pHMB in alkaline media. • 75–100% labelling of cysteines in proteins with pHMB. - Abstract: In this work we have studied the derivatization of protein disulfide bonds with p-Hydroxymercurybenzoate (pHMB) in strong alkaline medium without any preliminary reduction. The reaction has been followed by the determination of the protein–pHMB complex using size exclusion chromatography coupled to a microwave/UV mercury oxidation system for the on-line oxidation of free and protein-complexed pHMB and atomic fluorescence spectrometry (SEC–CVG–AFS) detection. The reaction has been optimized by an experimental design using lysozyme as a model protein and applied to several thiolic proteins. The proposed method reports, for the first time, that it is possible to label 75–100% cysteines of proteins and, thus, to determine thiolic proteins without the need of any reducing step to obtain reduced -SH groups before mercury labelling. We obtained a detection limit of 100 nmol L−1 based on a signal-to-noise ratio of 3 for unbound and complexed pHMB, corresponding to a detection limit of proteins ranged between 3 and 360 nmol L−1, depending on the number of cysteines in the protein sequence

  13. Novel graphite-carbon encased tungsten carbide nanocomposites by solid-state reaction and their ORR electrocatalytic performance in alkaline medium

    International Nuclear Information System (INIS)

    Novel nanocomposites of spherical graphite-carbon encased tungsten carbide (GC-WC) are synthesized by solid state reaction with melamine and WO3 as precursors under N2 atmosphere. The diameters of the GC-WC composites range from 50 to 200 nm and the WC nanoparticles inside with an average size of ca.15 nm distribute uniformly. The characterization results indicate that the GC-WC is composed of few layers of graphite carbon and WC nanoparticles with high crystallization and purity. Moreover, the electrocatalytic performance of GC-WC for the oxygen reduction reaction (ORR) in alkaline medium is further investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with or without 3 M methanol. The results show that GC-WC has a considerable performance for ORR in the view of activity, stability and methanol tolerance, which may further used as proper supports for noble-metal based ORR catalysts in alkaline fuel cell. The synergetic interaction between the carbide nanoparticles and graphite carbon, which means that the surface graphite carbon layers are activated by WC nanoparticles for ORR and in turn protect inner WC from highly oxidizing environments has also been verified

  14. Ethanol electro-oxidation in alkaline medium using Pd/MWCNT and PdAuSn/MWCNT electrocatalysts prepared by electron beam irradiation

    International Nuclear Information System (INIS)

    Environmental problems and the world growing demand for energy has mobilized the scientific community in finding of clean and renewable energy sources. In this context, fuel cells appear as appropriate technology for generating electricity through alcohols electro-oxidation. Multi Wall Carbon Nanotubes (MWCNT)-supported Pd and trimetallic PdAuSn (Pd:Au:Sn 50:10:40 atomic ratio) electrocatalysts were prepared using electron beam irradiation. The obtained materials were characterized by VC, Chronoamperometry, EDX, TEM and XRD. The catalytic activities of electrocatalysts toward ethanol electro-oxidation were evaluated in alkaline medium in a single alkaline direct ethanol fuel cell (ADEFC) in a range temperature 60 to 90 deg C. The best performances were obtained at 85 deg C: 33 mW.cm-2 and 31 mW.cm-2 for Pd/ MWCNT and PdAuSn/MWCNT electrocatalysts, respectively. X-ray diffractograms of electrocatalysts showed the presence of Pd-rich (fcc) and Au-rich (fcc) phases. Cyclic voltammetry and chronoamperometry experiments showed that PdAuSn/MWCNT electrocatalyst demonstrated similar activity toward ethanol electro-oxidation at room temperature, compared to electrocatalyst Pd/MWCNT. (author)

  15. Ethanol electro-oxidation in alkaline medium using Pd/c and PdRh/C electrocatalysts prepared by electron beam irradiation

    International Nuclear Information System (INIS)

    In this study, carbon-supported Pd (Pd/C) and bimetallic PdRh (Pd:Rh 90:10 atomic ratio) (PdRh/C) electrocatalysts were prepared using electron beam irradiation. The morphology and composition of the obtained materials were characterized by Cyclic voltammetry (VC), Chronoamperometry (CA), Energy dispersive X-ray (EDX), X-ray Diffraction (XRD) and Thermo-gravimetric analysis (TGA). The catalytic activities of the electrocatalysts toward the ethanol electro-oxidation were evaluated in alkaline medium in a single alkaline direct ethanol fuel cell (ADEFC), in a range temperature of 50 to 85 deg C. The best performances were obtained at 85 deg C (25 mW.cm-2) and 75 deg C (38 mW.cm-2) for Pd/C and PdRh/C electrocatalysts, respectively. The XRD of the PdRh/C electrocatalyst showed the presence of Pd-rich (fcc) phase. CV and CA experiments showed that PdRh/C electrocatalyst demonstrated superior activity toward ethanol electro-oxidation at room temperature, compared to Pd/C electrocatalyst. (author)

  16. Direct, simple derivatization of disulfide bonds in proteins with organic mercury in alkaline medium without any chemical pre-reducing agents

    Energy Technology Data Exchange (ETDEWEB)

    Campanella, Beatrice; Onor, Massimo [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM- UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ferrari, Carlo [National Research Council of Italy, C.N.R., Istituto Nazionale di Ottica, INO-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); D’Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM- UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM- UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2014-09-16

    Highlights: • A simple procedure for the derivatization of proteins disulfide bonds. • Cysteine groups in several proteins derivatised with pHMB in alkaline media. • 75–100% labelling of cysteines in proteins with pHMB. - Abstract: In this work we have studied the derivatization of protein disulfide bonds with p-Hydroxymercurybenzoate (pHMB) in strong alkaline medium without any preliminary reduction. The reaction has been followed by the determination of the protein–pHMB complex using size exclusion chromatography coupled to a microwave/UV mercury oxidation system for the on-line oxidation of free and protein-complexed pHMB and atomic fluorescence spectrometry (SEC–CVG–AFS) detection. The reaction has been optimized by an experimental design using lysozyme as a model protein and applied to several thiolic proteins. The proposed method reports, for the first time, that it is possible to label 75–100% cysteines of proteins and, thus, to determine thiolic proteins without the need of any reducing step to obtain reduced -SH groups before mercury labelling. We obtained a detection limit of 100 nmol L{sup −1} based on a signal-to-noise ratio of 3 for unbound and complexed pHMB, corresponding to a detection limit of proteins ranged between 3 and 360 nmol L{sup −1}, depending on the number of cysteines in the protein sequence.

  17. Ethanol electro-oxidation in alkaline medium using Pd/MWCNT and PdAuSn/MWCNT electrocatalysts prepared by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana Napoleao; Silva, Dionisio Furtunato da; Andrade e Silva, Leonardo Gondin de; Spinace, Estevam Vitorio; Oliveira Neto, Almir, E-mail: drinager@ig.com.br, E-mail: dfsilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Santos, Mauro Coelho dos [Universidade Federal do ABC (LEMN/CCNH/UFABC), Santo Andre, SP (Brazil)

    2015-07-01

    Environmental problems and the world growing demand for energy has mobilized the scientific community in finding of clean and renewable energy sources. In this context, fuel cells appear as appropriate technology for generating electricity through alcohols electro-oxidation. Multi Wall Carbon Nanotubes (MWCNT)-supported Pd and trimetallic PdAuSn (Pd:Au:Sn 50:10:40 atomic ratio) electrocatalysts were prepared using electron beam irradiation. The obtained materials were characterized by VC, Chronoamperometry, EDX, TEM and XRD. The catalytic activities of electrocatalysts toward ethanol electro-oxidation were evaluated in alkaline medium in a single alkaline direct ethanol fuel cell (ADEFC) in a range temperature 60 to 90 deg C. The best performances were obtained at 85 deg C: 33 mW.cm{sup -2} and 31 mW.cm{sup -2} for Pd/ MWCNT and PdAuSn/MWCNT electrocatalysts, respectively. X-ray diffractograms of electrocatalysts showed the presence of Pd-rich (fcc) and Au-rich (fcc) phases. Cyclic voltammetry and chronoamperometry experiments showed that PdAuSn/MWCNT electrocatalyst demonstrated similar activity toward ethanol electro-oxidation at room temperature, compared to electrocatalyst Pd/MWCNT. (author)

  18. Ethanol electro-oxidation in alkaline medium using Pd/c and PdRh/C electrocatalysts prepared by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Dionisio Furtunato da; Geraldes, Adriana Napoleao; Pino, Eddy Segura; Spinace, Estevam Vitorio; Oliveira Neto, Almir; Linardi, Marcelo, E-mail: dfsilva@ipen.br, E-mail: drinager@ig.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    In this study, carbon-supported Pd (Pd/C) and bimetallic PdRh (Pd:Rh 90:10 atomic ratio) (PdRh/C) electrocatalysts were prepared using electron beam irradiation. The morphology and composition of the obtained materials were characterized by Cyclic voltammetry (VC), Chronoamperometry (CA), Energy dispersive X-ray (EDX), X-ray Diffraction (XRD) and Thermo-gravimetric analysis (TGA). The catalytic activities of the electrocatalysts toward the ethanol electro-oxidation were evaluated in alkaline medium in a single alkaline direct ethanol fuel cell (ADEFC), in a range temperature of 50 to 85 deg C. The best performances were obtained at 85 deg C (25 mW.cm{sup -2}) and 75 deg C (38 mW.cm{sup -2}) for Pd/C and PdRh/C electrocatalysts, respectively. The XRD of the PdRh/C electrocatalyst showed the presence of Pd-rich (fcc) phase. CV and CA experiments showed that PdRh/C electrocatalyst demonstrated superior activity toward ethanol electro-oxidation at room temperature, compared to Pd/C electrocatalyst. (author)

  19. Ultrasonic-assisted synthesis of Pd-Pt/carbon nanotubes nanocomposites for enhanced electro-oxidation of ethanol and methanol in alkaline medium.

    Science.gov (United States)

    Yang, Guohai; Zhou, Yazhou; Pan, Horng-Bin; Zhu, Chengzhou; Fu, Shaofang; Wai, Chien M; Du, Dan; Zhu, Jun-Jie; Lin, Yuehe

    2016-01-01

    Herein, a facile ultrasonic-assisted strategy was proposed to fabricate the Pd-Pt alloy/multi-walled carbon nanotubes (Pd-Pt/CNTs) nanocomposites. A good number of Pd-Pt alloy nanoparticles with an average of 3.4 ± 0.5 nm were supported on sidewalls of CNTs with uniform distribution. The composition of the Pd-Pt/CNTs nanocomposites could also be easily controlled, which provided a possible approach for the preparation of other architectures with anticipated properties. The Pd-Pt/CNTs nanocomposites were extensively studied by electron microscopy, induced coupled plasma atomic emission spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and applied for the ethanol and methanol electro-oxidation reaction in alkaline medium. The electrochemical results indicated that the nanocomposites had better electrocatalytic activities and stabilities, showing promising applications for fuel cells. PMID:26384899

  20. Copper–zinc electrodeposition in alkaline-sorbitol medium: Electrochemical studies and structural, morphological and chemical composition characterization

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, M.R.H. de [Faculdades Integradas Maria Imaculada, Rua Paula Bueno 240, Mogi Guaçu, SP (Brazil); Barbano, E.P.; Carvalho, M.F. de [Universidade Federal de São Carlos, Via Washington Luís km 235, São Carlos, SP (Brazil); Tulio, P.C. [Universidade Tecnológica Federal do Paraná, Av. Alberto Carazzai 1640, Cornélio Procópio, PR (Brazil); Carlos, I.A., E-mail: diac@ufscar.br [Universidade Federal de São Carlos, Via Washington Luís km 235, São Carlos, SP (Brazil)

    2015-04-01

    Highlights: • Cu–Zn electrodeposition was investigated galvanostatically. • Coloration of Cu–Zn films were whitish golden, light golden, golden/gray. • Electrodeposits produced from Cu70/Zn30 bath showed higher Cu content at lower j. • Scanning electron microscopy showed that Cu–Zn electrodeposits were fine-grained. • X-ray analysis of the Cu–Zn electrodeposits suggested a mixture of phases. - Abstract: The galvanostatic technique was used to analyze the electrodeposition of Cu–Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu–Zn films were whitish golden, light golden, golden/gray depending on the Cu{sup 2+}/Zn{sup 2+} ratios in the electrodeposition bath, deposition current density (j{sub dep}) and charge density (q{sub dep}). The highest current efficiency was ∼54.0%, at j{sub dep} −1.0 mA cm{sup −2} and q{sub dep} 0.40 C cm{sup −2} in the Cu70/Zn30 bath. Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower j{sub dep}. Also, for same j{sub dep} the Cu content increased with q{sub dep}. Scanning electron microscopy showed that Cu–Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at j{sub dep} −20.0 mA cm{sup −2} and q{sub dep} 10.0 C cm{sup −2}. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu–Zn electrodeposits obtained at j{sub dep} −8.0, −20.0 and −40.0 mA cm{sup −2}, in each case, with q{sub dep} 2.0 and 10.0 C cm{sup −2}, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn{sub 5} and Cu{sub 5}Zn{sub 8}. Galvanostatic electrodeposits of Cu–Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications

  1. Copper–zinc electrodeposition in alkaline-sorbitol medium: Electrochemical studies and structural, morphological and chemical composition characterization

    International Nuclear Information System (INIS)

    Highlights: • Cu–Zn electrodeposition was investigated galvanostatically. • Coloration of Cu–Zn films were whitish golden, light golden, golden/gray. • Electrodeposits produced from Cu70/Zn30 bath showed higher Cu content at lower j. • Scanning electron microscopy showed that Cu–Zn electrodeposits were fine-grained. • X-ray analysis of the Cu–Zn electrodeposits suggested a mixture of phases. - Abstract: The galvanostatic technique was used to analyze the electrodeposition of Cu–Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu–Zn films were whitish golden, light golden, golden/gray depending on the Cu2+/Zn2+ ratios in the electrodeposition bath, deposition current density (jdep) and charge density (qdep). The highest current efficiency was ∼54.0%, at jdep −1.0 mA cm−2 and qdep 0.40 C cm−2 in the Cu70/Zn30 bath. Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower jdep. Also, for same jdep the Cu content increased with qdep. Scanning electron microscopy showed that Cu–Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at jdep −20.0 mA cm−2 and qdep 10.0 C cm−2. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu–Zn electrodeposits obtained at jdep −8.0, −20.0 and −40.0 mA cm−2, in each case, with qdep 2.0 and 10.0 C cm−2, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn5 and Cu5Zn8. Galvanostatic electrodeposits of Cu–Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications, especially for decorative purposes

  2. TiO2 obtained by laser ablation and it response in alkaline medium for the oxygen detachment reaction

    International Nuclear Information System (INIS)

    The performance of the photo electrocatalysts materials depends on one hand of the it structures of the crystalline lattice and of their surface properties, those which in turn are determined by the material preparation method. In this work the laser ablation technique to obtain thin films of titanium dioxide on recovered glass with tin oxide is presented. The carried out analyses showed homogeneous films, one of amorphous titanium oxide with a band width of 3.43 eV and the other one with anatase structure with a band energy of 3.41 eV. The photoresponse for the oxygen detachment it was better for the anatase. In a 0.1M KOH medium it was found corrosion in the films. (Author)

  3. Ethanol electro-oxidation in an alkaline medium using Pd/C, Au/C and PdAu/C electrocatalysts prepared by electron beam irradiation

    International Nuclear Information System (INIS)

    Carbon-supported Pd, Au and bimetallic PdAu (Pd:Au 90:10, 50:50 and 30:70 atomic ratios) electrocatalysts were prepared using electron beam irradiation. The obtained materials were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their catalytic activities toward ethanol electro-oxidation were evaluated in an alkaline medium using electrochemical techniques, in situ attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR) analysis and a single alkaline direct ethanol fuel cell (ADEFC). EDX analyses showed that the actual Pd:Au atomic ratios were very similar to the nominal ones. X-ray diffractograms of PdAu/C electrocatalysts evidenced the presence of Pd-rich (fcc) and Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles on the carbon support, with an average size in the range of 3–5 nm and broad size distributions. Cyclic voltammetry (CV) and chronoamperometry (CA) experiments revealed the superior ambient activity toward ethanol electro-oxidation of PdAu/C electrocatalysts with Pd:Au ratios of 90:10 and 50:50. In situ ATR-FTIR spectroscopy measurements have shown that the mechanism for ethanol electro-oxidation is dependent on catalyst composition, leading to different reaction products, such as acetaldehyde and acetate, depending on the number of electrons transferred. Experiments on a single ADEFC were conducted between 50 and 90 °C, and the best performance of 44 mW cm−2 in 2.0 mol L−1 ethanol was obtained at 85 °C for the Pd:Au 90:10 catalysts. This superior performance is most likely associated with enhancement of ethanol adsorption on Pd, oxidation of the intermediates, the presence of gold oxide-hydroxyl species, low mean particle diameters and better distribution of particles on the support

  4. A McOndo Writer's Take on Literature in the Era of Audiovisual and Digital Communication: The Case of Alberto Fuguet's "Las Peliculas de mi vida"

    Science.gov (United States)

    Maier, Linda S.

    2011-01-01

    Alberto Fuguet, one of the leaders of the McOndo writers who seek cultural direction from the United States and exploit mass-media formulas, is a polarizing figure in contemporary Latin American culture. His most recent full-length novel, the semi-autobiographical "Las peliculas de mi vida" (2003), has led many to conclude that Fuguet is simply a…

  5. Comprehensive Study of an Earth-Abundant Bifunctional 3D Electrode for Efficient Water Electrolysis in Alkaline Medium.

    Science.gov (United States)

    Sharifi, Tiva; Gracia-Espino, Eduardo; Jia, Xueen; Sandström, Robin; Wågberg, Thomas

    2015-12-30

    We report efficient electrolysis of both water-splitting half reactions in the same medium by a bifunctional 3D electrode comprising Co3O4 nanospheres nucleated on the surface of nitrogen-doped carbon nanotubes (NCNTs) that in turn are grown on conductive carbon paper (CP). The resulting electrode exhibits high stability and large electrochemical activity for both oxygen and hydrogen evolution reactions (OER and HER). We obtain a current density of 10 mA/cm(2) in 0.1 M KOH solution at overpotentials of only 0.47 and 0.38 V for OER and HER, respectively. Additionally, the experimental observations are understood and supported by analyzing the Co3O4:NCNT and NCNT:CP interfaces by ab initio calculations. Both the experimental and the theoretical studies indicate that firm and well-established interfaces along the electrode play a crucial role on the stability and electrochemical activity for both OER and HER. PMID:26629887

  6. Statistical medium optimization of an alkaline protease from Pseudomonas aeruginosa MTCC 10501, its characterization and application in leather processing.

    Science.gov (United States)

    Boopathy, Naidu Ramachandra; Indhuja, Devadas; Srinivasan, Krishnan; Uthirappan, Mani; Gupta, Rishikesh; Ramudu, Kamini Numbi; Chellan, Rose

    2013-04-01

    Proteases are shown to have greener mode of application in leather processing for dehairing of goat skins and cow hides. Production of protease by submerged fermentation with potent activity is reported using a new isolate P. aeruginosa MTCC 10501. The production parameters were optimized by statistical methods such as Plackett-Burman and response surface methodology. The optimized production medium contained (g/L); tryptone, 2.5; yeast extract, 3.0; skim milk 30.0; dextrose 1.0; inoculum concentration 4%: initial pH 6.0; incubation temperature 30 degrees C and optimum production at 48 h with protease activity of 7.6 U/mL. The protease had the following characteristics: pH optima, 9.0; temperature optima 50 degrees C; pH stability between 5.0-10.0 and temperature stability between 10-40 degrees C. The protease was observed to have high potential for dehairing of goat skins in the pre- tanning process comparable to that of the chemical process as evidenced by histology. The method offers cleaner processing using enzyme only instead of toxic chemicals in the pre-tanning process of leather manufacture. PMID:24195353

  7. A New Alkaline pH-Adjusted Medium Enhances Detection of β-Hemolytic Streptococci by Minimizing Bacterial Interference Due to Streptococcus salivarius

    Science.gov (United States)

    Dierksen, Karen P.; Ragland, Nancy L.; Tagg, John R.

    2000-01-01

    A new selective medium (CNA-P) that reduces or eliminates the inhibitory activity of bacteriocin-producing Streptococcus salivarius against β-hemolytic streptococci has been developed and compared with sheep blood agar (SBA) for the sensitive detection of small numbers of β-hemolytic streptococci in clinical specimens. CNA-P has as its basis a commercial medium (Difco Columbia CNA agar) supplemented with 5% (vol/vol) sheep blood, and the CNA is further modified by addition of 100 mM PIPES buffer [piperazine-N,N′-bis(2-ethanesulfonic acid)] (pH 7.5) to maintain cultures at an alkaline pH during incubation. CNA-P was shown to inhibit the production and/or release of four different types of S. salivarius bacteriocins or bacteriocin-like inhibitory molecules. The efficacies of CNA-P and SBA for detection of β-hemolytic streptococci in 1,352 pharyngeal samples from 376 children were compared. The β-hemolytic streptococcal isolates recovered from the samples included 314 group A (S. pyogenes), 61 group G, 33 group B, and 5 group C streptococci. Of 314 samples that yielded S. pyogenes, 300 were positive on CNA-P (96%) and 264 (86%) were positive on SBA. A significantly greater number of S. pyogenes isolates from these samples were recovered only on CNA-P (50 of 314) compared with the number of isolates recovered only on SBA (14 of 314). In addition, the degree of positivity, a measure of the total numbers of S. pyogenes isolates on the plate, was significantly higher on CNA-P than on SBA (2.40 versus 2.07; P < 0.001). Interestingly, CNA-P was also found to enhance the hemolytic activity of streptolysin O, allowing detection of streptolysin S-deficient S. pyogenes strains which might otherwise go undetected on SBA and other isolation media. PMID:10655361

  8. N-doped carbon@Ni-Al2O3 nanosheet array@graphene oxide composite as an electrocatalyst for hydrogen evolution reaction in alkaline medium

    Science.gov (United States)

    Wang, Juan; Qiu, Tian; Chen, Xu; Lu, Yanluo; Yang, Wensheng

    2015-10-01

    An NiAl-layered double-hydroxide (NiAl-LDH) nanosheet array is grown on a graphene oxide (GO) substrate (NiAl-LDH@GO) by the hydrothermal method. The NiAl-LDH@GO is used as the precursor to synthetize an N-doped carbon@Ni-Al2O3 nanosheet array@GO composite (N-C@Ni-Al2O3@GO) by coating with dopamine followed by calcination. The N-C@Ni-Al2O3@GO is used as a non-noble metal electrocatalyst for hydrogen evolution reaction in alkaline medium, and exhibits high electrocatalytic activity with low onset overpotential (-75 mV). The improved electrocatalytic performance of N-C@Ni-Al2O3@GO arises from its intrinsic features. First, it has a high specific surface area with the Ni nanoparticles in the composite dispersed well and the sizes of Ni nanoparticles are small, which lead to the exposure of more active sites for electrocatalysis. Second, there is a synergistic effect between the Ni nanoparticles and the N-C coating layer, which is beneficial to reduce the activation energy of the Volmer step and improve the electrocatalytic activity. Third, the N-C coating layer and the XC-72 additive can form an electrically conductive network, which serves as a bridge for the transfer of electrons from the electrode to the Ni nanoparticles.

  9. Preparation of Pt Au/C and Pt Au Bi/C electrocatalysts using electron beam irradiation for ethanol electro-oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Pt Au/C (50:50) and PtAuBi/C electrocatalysts with Pt:Au:Bi atomic ratios of 50:40:10, 50:30:20 and 50:10:40 were prepared in water/2-propanol using electron beam irradiation. The materials were characterized by X-ray diffraction (XRD) and the electro-oxidation of ethanol was studied by chronoamperometry at room temperature. The X-ray diffraction measurements for all electrocatalysts prepared showed four peaks, which are associated with the planes of the face-centered cubic (fcc) structure characteristic of Pt and Pt alloys. For PtAuBi/C it was also observed the presence of a mixture of BiPt alloys and bismuth phases. The average crystallite sizes for Pt/C, PtAu/C, PtAuBi/C (50:40:10), PtAuBi/C (50:30:20) and PtAuBi/C (50:10:40) were in the range of 2.0 - 4.0 nm. The activity of the electrocatalysts for ethanol oxidation in alkaline medium showed that PtAuBi/C (50:40:10) had a higher performance for ethanol oxidation compared to others electrocatalysts prepared. (author)

  10. Mechanistic aspects of Os(VIII) catalysed oxidation of loop diuretic drug furosemide by Ag(III) periodate complex in aqueous alkaline medium

    Indian Academy of Sciences (India)

    Shweta J Malode; Nagaraj P Shetti; Sharanappa T Nandibewoor

    2012-03-01

    The kinetics of oxidation of a loop diuretic drug furosemide (Fur) by diperiodatoargentate(III) (DPA) has been investigated in the presence of osmium(VIII) (Os(VIII)) used as homogeneous catalyst in alkaline medium at a constant ionic strength of 0.20mol dm-3 spectrophotometrically attached with HI-TECH SFA-12 stopped flow accessory. The stoichiometry was 1:2 (Fur:DPA). The order of the reaction with respect to [DPA] was unity while the order with respect to [Fur] was less than unity over the concentration range studied. The rate increased with an increase in [OH−] and decreased with an increase in [IO$^{−}_{4}$]. The order with respect to [Os(VIII)] was unity. The oxidation products were identified as 2-(4-carboxy-2-oxo-but-3-enylamino)-4-chloro-5-sulfamoyl-benzoic acid and Ag(I). A suitable mechanism was proposed. The reaction constants involved in the different steps of the reaction mechanism were calculated. Kinetic experiments suggest that [Ag(H2IO6)(H2O)2] is the reactive silver(III) species and [OsO4(OH)2]2− is the reactive Os(VIII) species.

  11. High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Highlights: •An ORR electrocatalyst was fabricated from blood biomass and carbon nanotube. •The N-CNT catalyst exhibits good ORR activity, methanol resistance and stability. •The pyrolysis process produces high contents of pyridinic and pyrrolic N species. •The pyridinic-N group may play more important role in the active sites for ORR. -- Abstract: Here we present a facile synthetic route to design nitrogen-doped nanostructured carbon-based electrocatalyst for oxygen reduction reaction (ORR) by the copyrolysis of blood biomass from pig and carbon nanotubes (CNTs) at high temperatures. The nitrogen-doped CNTs obtained at 800 °C not only results in excellent ORR activity with four-electron transfer selectivity in alkaline medium, but also exhibits superior methanol-tolerant property and long-term stability. It is confirmed that high-temperature pyrolysis processes can facilitate to produce higher contents of pyridinic- and pyrrolic-N binding groups in electrocatalysts, contributing to the enhancement of ORR performance in terms of onset potential, half-wave potential, and limited current density. We also propose that the planar-N configuration may be the active site that is responsible for the improved ORR electrocatalytic performance. The straight-forward and cheap synthesis of the active and stable electrocatalyst makes it a promising candidate for electrochemical power sources such as fuel cells or metal-air batteries

  12. Growth of uniform lath-like α-(Fe,Al)OOH and disc-like α-(Fe,Al)2O3 nanoparticles in a highly alkaline medium

    International Nuclear Information System (INIS)

    The effects of aluminium (Al3+)-dopant on the precipitation of uniform lath-like α-FeOOH particles, the obtention and growth of α-(Fe,Al)OOH and α-(Fe,Al)2O3 solid solutions, particle size and shape were investigated using X-ray powder diffraction, Moessbauer and Fourier transform infrared spectroscopies, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Acicular α-FeOOH particles, precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH), were used as reference material. The influence of Al-dopant was investigated by adding varying amounts of Al3+ ions to the initial FeCl3 solution. In the presence of lower concentrations of aluminium ions (up to 11.11 mol%) α-(Fe,Al)OOH as a single phase was formed, whereas higher concentrations led to an additional obtention and growth of α-(Fe,Al)2O3. Al-for-Fe substitution in the α-FeOOH and α-Fe2O3 structures was confirmed by a decrease in the unit-cell dimensions, a decrease in the hyperfine magnetic field and an increase in the wave number of the infrared absorption bands. The presence of lower concentrations of aluminium ions (up to 11.11 mol%) in the precipitation system did not affect the size and shape of the α-(Fe,Al)OOH particles, whereas higher concentrations influenced a decrease in the length and aspect ratio. In the presence of 42.86 mol% Al3+ ions fairly uniform disc-shaped α-(Fe,Al)2O3 were formed.

  13. Photo-Fenton oxidation of phenol and organochlorides (2,4-DCP and 2,4-D) in aqueous alkaline medium with high chloride concentration.

    Science.gov (United States)

    Luna, Airton J; Chiavone-Filho, Osvaldo; Machulek, Amilcar; de Moraes, José Ermírio F; Nascimento, Cláudio A O

    2012-11-30

    A highly concentrated aqueous saline-containing solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a system composed of an annular reactor with a quartz immersion well and a medium-pressure mercury lamp (450 W). The study was conducted under special conditions to minimize the costs of acidification and neutralization, which are usual steps in this type of process. Photochemical reactions were carried out to investigate the influence of some process variables such as the initial concentration of Fe(2+) ([Fe(2+)](0)) from 1.0 up to 2.5 mM, the rate in mmol of H(2)O(2) fed into the system (FH(2)O(2);in) from 3.67 up to 7.33 mmol of H(2)O(2)/min during 120 min of reaction time, and the initial pH (pH(0)) from 3.0 up to 9.0 in the presence and absence of NaCl (60.0 g/L). Although the optimum pH for the photo-Fenton process is about 3.0, this particular system performed well in experimental conditions starting at alkaline and neutral pH. The results obtained here are promising for industrial applications, particularly in view of the high concentration of chloride, a known hydroxyl radical scavenger and the main oxidant present in photo-Fenton processes. PMID:22809483

  14. Preparation and characterization of electrocatalysts based on palladium for electro-oxidation of alcohols in alkaline medium; Preparacao e caracterizacao de eletrocatalisadores a base de paladio para oxidacao eletroquimica de alcoois em meio alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Brandalise, Michele

    2012-07-01

    In this study Pd/C, Au/C, PdAu/C, PdAuPt/C, PdAuBi/C and PdAuIr/C electrocatalysts were prepared by the sodium borohydride reduction method for the electrochemical oxidation of methanol, ethanol and ethylene glycol. This methodology consists in mix an alkaline solution of sodium borohydride to a mixture containing water/isopropyl alcohol, metallic precursors and the Vulcan XC 72 carbon support. The electrocatalysts were characterized by energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry. The electrochemical oxidation of the alcohols was studied by chronoamperometry using a thin porous coating technique. The mechanism of ethanol electro-oxidation was studied by Fourier Transformed Infrared (FTIR) in situ. The most effective electrocatalysts were tested in alkaline single cells directly fed with methanol, ethanol or ethylene glycol. Preliminary studies showed that the most suitable atomic composition for preparing the ternary catalysts is 50:45:05. Electrochemical data in alkaline medium show that the electrocatalysts PdAuPt/C (50:45:05) showed the better activity for methanol electro oxidation, while PdAuIr/C was the most active for ethanol oxidation and PdAuBi/C (50:45:05) was the most effective for ethylene glycol oxidation in alkaline medium. These results show that the addition of gold in the composition of electrocatalysts increases their catalytic activities. The spectroelectrochemical FTIR in situ data permitted to conclude that C-C bond is not broken and the acetate is formed. (author)

  15. Highly porous nickel@carbon sponge as a novel type of three-dimensional anode with low cost for high catalytic performance of urea electro-oxidation in alkaline medium

    Science.gov (United States)

    Ye, Ke; Zhang, Dongming; Guo, Fen; Cheng, Kui; Wang, Guiling; Cao, Dianxue

    2015-06-01

    Highly porous nickel@carbon sponge electrode with low cost is synthesized via a facile sponge carbonization method coupled with a direct electrodeposition of Ni. The obtained electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The catalytic performances of urea electro-oxidation in alkaline medium are investigated by cyclic voltammetry (CV) and chronoamperometry (CA). The Ni@carbon sponge electrode exhibits three-dimensional open network structures with a large surface area. Remarkably, the Ni@carbon sponge electrode shows much higher electrocatalytic activity and lower onset oxidation potential towards urea electro-oxidation compared to a Ni/Ti flat electrode synthesized by the same procedure. The Ni@carbon sponge electrode achieves an onset oxidation potential of 0.24 V (vs. Ag/AgCl) and a peak current density of 290 mA cm-2 in 5 mol L-1 NaOH and 0.10 mol L-1 urea solutions accompanied with a desirable stability. The impressive electrocatalytic activity is largely attributed to the high intrinsic electronic conductivity, superior porous network structures and rich surface Ni active species, which can largely boost the interfacial electroactive sites and charge transfer rates for urea electro-oxidation in alkaline medium, indicating promising applications in fuel cells.

  16. Evaluation of nickel-rich alloys for the electrolytic generation of hydrogen in an alkaline medium; Evaluacion de aleaciones ricas en niquel para la generacion electrolitica de hidrogeno en medio alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz Verdin, A.A.; Ortega Borges, R.; Trejo Cordova, G.; Meas Vong, Y. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C., Pedro Escobedo, Queretaro (Mexico)]. E-mail: aortiz@cideteq.mx

    2009-09-15

    The simultaneous electrodeposition of Ni with metals such as Zn to form alloys enables obtaining surfaces with high electrocatalytic activity or particular characteristics that resist wear and abrasion. This work presents the results of the study of the electrochemical characterization of different types of nickel electrodeposition and compositions, used as cathodes, and measurements of the electrocatalytic activity in the release of hydrogen in an alkaline medium. Curves I through IV were generated, which were potentiostatically obtained in a nitrogen atmosphere in a NaOH alkaline solution. The morphology of the deposits was evaluated with sweep electron micrscopy(SEM). The results enabled evaluating its potential application as electrode materials for the generation of electrolytic hydrogen in alkaline medium, given the good electrocatalytic activity of nickel-rich materials. [Spanish] El electrodeposito simultaneo del Ni, con metales como el Zn para formar aleaciones, permite obtener superficies con elevada actividad electrocatalitica o con caracteristicas particulares de resistencia al desgaste y abrasion. En este trabajo se presentan los resultados del estudio de la caracterizacion electroquimica de los electrodepositos a base de niquel de diferente naturaleza y composicion utilizandolos como catodos midiendo la actividad electrocatalitica con respecto a la reaccion de desprendimiento de hidrogeno (RDH) en medio alcalino. Se realizaron curvas I vs V obtenidas potenciostaticamente bajo atmosfera de nitrogeno en una solucion alcalina de NaOH. La morfologia de los depositos se evaluo mediante SEM (microscopio electronico de barrido). Los resultados permiten evaluar su potencial aplicacion como materiales de electrodo para la generacion electrolitica de hidrogeno en medio alcalino, dada la buena actividad electrocatalitica de los materiales ricos en niquel.

  17. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

    Directory of Open Access Journals (Sweden)

    Florica Simescu and Hassane Idrissi

    2008-01-01

    Full Text Available We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO46(OH2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  18. A comparative investigation of metal-support interactions on the catalytic activity of Pt nanoparticles for ethanol oxidation in alkaline medium

    Science.gov (United States)

    Godoi, Denis R. M.; Villullas, Hebe M.; Zhu, Fu-Chun; Jiang, Yan-Xia; Sun, Shi-Gang; Guo, Junsong; Sun, Lili; Chen, Rongrong

    2016-04-01

    The effects of interactions of Pt nanoparticles with hybrid supports on reactivity towards ethanol oxidation in alkaline solution are investigated. Studies involve catalysts with identical Pt nanoparticles on six hybrid supports containing carbon powder and transition metal oxides (TiO2, ZrO2, SnO2, CeO2, MoO3 and WO3). In situ X-ray absorption spectroscopy (XAS) results evidence that metal-support interactions produce changes in the Pt 5d band vacancy, which appears to determine the catalytic activity. The highest and lowest activities are observed for Pt nanoparticles on hybrid supports containing TiO2 and CeO2, respectively. Further studies are presented for these two catalysts. In situ FTIR reflection spectroscopy measurements, taken using both multi-stepped FTIR spectroscopy (MS-FTIR) and single potential alteration FTIR spectroscopy (SPA-FTIR), evidence that the main product of ethanol oxidation is acetate, although signals attributed to carbonate and CO2 indicate some differences in CO2 production. Fuel cell performances of these catalysts, tested in a 4.5 cm2 single cell at different temperatures (40-90 °C) show good agreement with data obtained by electrochemical techniques. Results of this comprehensive study point out the possibility of compensating a reduction of noble metal load with an increase in activity promoted by interactions between metallic nanoparticles and a support.

  19. Synthesis of silver/nitrogen-doped reduced graphene oxide through a one-step thermal solid-state reaction for oxygen reduction in an alkaline medium

    Science.gov (United States)

    Soo, Li Ting; Loh, Kee Shyuan; Mohamad, Abu Bakar; Daud, Wan Ramli Wan; Wong, Wai Yin

    2016-08-01

    One of the obstacles to the commercialisation of fuel cells is the high cost of noble metals, such as platinum, that are used as electrocatalysts. Silver-incorporated nitrogen-doped reduced graphene oxide (Ag/N-rGO) has been synthesised through the simple annealing of metal salts with graphene oxide and melamine. The presence of silver and nitrogen atoms in Ag/N-rGO was confirmed by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) analysis. Both the XPS and EDS results showed a higher Ag loading on the N-rGO surface compared with the rGO surface. Transmission electron microscopy (TEM) images revealed a wide size distribution of Ag particles loaded on the N-rGO surface. Electrochemical results indicate that N-rGO is a better support for Ag than rGO. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) results indicate that Ag/N-rGO is a potential ORR catalyst candidate in alkaline as it exhibited an onset potential of -0.15 V vs. Ag/AgCl and a limiting diffusion current density of -4.38 mA cm-2 with four electron pathways. In addition, Ag/N-rGO also showed better methanol tolerance than Pt/C.

  20. Glycerol electro-oxidation in alkaline medium using Pd/C and PdSn/C electrocatalysts prepared by electron beam irradiation

    International Nuclear Information System (INIS)

    Carbon-supported metal nanoparticles were prepared for fuel cell applications by radiation-induced reduction of metal ions precursors. Pd/C and PdSn/C electrocatalysts (Pd:Sn atomic ratio 90:10), prepared by using electron beam irradiation, were tested for glycerol electro-oxidation in single alkaline direct glycerol fuel cell (ADGFC). EDX analysis showed that the Pd:Sn atomic ratio is very similar to the nominal one. X-ray diffractograms of PdSn/C electrocatalyst showed the presence of Pd (fcc) phase. Cyclic voltammetry (CV) indicated that Pd/C and PdSn/C electrocatalysts have good activity for glycerol electro-oxidation, at room temperature. Experiments with single ADGFC were carried out from 60 to 90 deg C, using Pd/C and PdSn/C electrocatalysts and glycerol 2.0 mol.L-1, as fuel. The best performance was obtained at 85 deg C, for both electrocatalysts. The Pd/C and PdSn/C electrocatalysts showed similar performance (34 mW cm-2), at 85 deg C. (author)

  1. Glycerol electro-oxidation in alkaline medium using Pd/C and PdSn/C electrocatalysts prepared by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana Napoleao; Silva, Dionisio Fortunato da; Pino, Eddy Segura; Spinace, Estevan Vitorio; Oliveira Neto, Almir; Linardi, Marcelo, E-mail: drinager@ig.com.br, E-mail: dfsilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Santos, Mauro Coelhos dos [Universidade Federal do ABC (LEMN/UFABC), Santo Andre, SP (Brazil)

    2013-07-01

    Carbon-supported metal nanoparticles were prepared for fuel cell applications by radiation-induced reduction of metal ions precursors. Pd/C and PdSn/C electrocatalysts (Pd:Sn atomic ratio 90:10), prepared by using electron beam irradiation, were tested for glycerol electro-oxidation in single alkaline direct glycerol fuel cell (ADGFC). EDX analysis showed that the Pd:Sn atomic ratio is very similar to the nominal one. X-ray diffractograms of PdSn/C electrocatalyst showed the presence of Pd (fcc) phase. Cyclic voltammetry (CV) indicated that Pd/C and PdSn/C electrocatalysts have good activity for glycerol electro-oxidation, at room temperature. Experiments with single ADGFC were carried out from 60 to 90 deg C, using Pd/C and PdSn/C electrocatalysts and glycerol 2.0 mol.L{sup -1}, as fuel. The best performance was obtained at 85 deg C, for both electrocatalysts. The Pd/C and PdSn/C electrocatalysts showed similar performance (34 mW cm{sup -2}), at 85 deg C. (author)

  2. Degradation of amaranth dye in alkaline medium by ultrasonic cavitation coupled with electrochemical oxidation using a boron-doped diamond anode

    International Nuclear Information System (INIS)

    Amaranth dye is used widely in the processing of paper, textiles, foods, cosmetics, beverages and medicines, and effluents contaminated with this compound are discharged daily into the environment. Recent studies have shown that azo dyes, especially those such as amaranth dye that have been classified as endocrine disruptors, may cause adverse effects to animal and human health. This paper describes the application of electrochemical oxidation (with a boron-doped diamond BDD thin-film anode) coupled with ultrasound sonolysis (20 kHz and 523 W cm−2) to the removal of amaranth dye from dilute alkaline solution. The electrochemical and sonoelectrochemical processes (ECh and SECh, respectively) were carried out at constant current density (10 to 50 mA cm−2) in a single compartment cylindrical cell. Sonolysis was virtually less useful for the decolorization and degradation of amaranth dye, whilst ECh and SECh were more effective in degrading the dye with almost complete removal (90 - 95%) attained after 90 min of experiment at an applied current density of 50 mA cm−2. Degradation of the dye followed pseudo first-order kinetics in both processes, but the rate of reaction was faster with the SECh treatment confirming a synergistic effect between the cavitation process and the electrochemical system. Additionally, at low applied current densities (10 and 25 mA cm−2), SECh was considerably more effective than ECh for the amaranth dye mineralization. Although at 35 and 50 mA cm−2, the two processes showed the respective removal of total organic carbon values: (i) 85% for the ECh and 90% for the SECh at 35 mA cm−2; (ii) 96% for the ECh and 98% for the SECh at 50 mA cm−2. It is concluded that SECh presented the most favorable results for the decontamination of wastewaters containing azo dye compounds

  3. A sensitive inhibition chemiluminescence method for the determination of 6-mercaptopurine in tablet and biological fluid using the reaction of luminol-Ag(III) complex in alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hanwen, E-mail: hanwen@hbu.edu.cn [College of Chemistry and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002 (China); Wang, Ting; Liu, Xuyang; Chen, Peiyun [College of Chemistry and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002 (China)

    2013-02-15

    A sensitive inhibition chemiluminescence (CL) method for the determination of 6-mercaptopurine (6-MP) is developed. The mechanism of the CL reaction between Ag(III) complex {l_brace}[Ag(HIO{sub 6}){sub 2}]{sup 5-}{r_brace} and luminol in alkaline solution was proposed, along with the inhibition mechanism of 6-MP on the CL emission. The inhibition degree of CL emission was proportional to the logarithm of 6-MP concentration. The effects of the reaction conditions on CL emission and inhibition were examined. Under the optimized conditions, the detection limit (s/n=3) was 3.7 Multiplication-Sign 10{sup -10} g ml{sup -1}. The recoveries of 6-MP were in the range of 97.7-105% with the RSD of 2.1-3.4% (n=5) for tablet samples, 103-106% with the RSDs of 1.1-2.1% for spiked serum sample, and 97.2-101% with the RSD of 2.0-4.5% for spiked urine sample. The accuracy of this method for the tablet analysis was examined by comparing with the pharmacopoeia method. The proposed method was used for the determination of 6-MP at clinically relevant concentrations in real urine and serum samples with satisfactory results. - Highlights: Black-Right-Pointing-Pointer A sensitive inhibition chemiluminescence (CL) method for the determination of 6-MP is developed. Black-Right-Pointing-Pointer The inhibition mechanism of 6-MP on the CL emission was proposed. Black-Right-Pointing-Pointer The detection limit was 3.7 Multiplication-Sign 10{sup -10} g ml{sup -1}. Black-Right-Pointing-Pointer The accuracy was examined by comparing with the pharmacopoeia method.

  4. A sensitive inhibition chemiluminescence method for the determination of 6-mercaptopurine in tablet and biological fluid using the reaction of luminol–Ag(III) complex in alkaline medium

    International Nuclear Information System (INIS)

    A sensitive inhibition chemiluminescence (CL) method for the determination of 6-mercaptopurine (6-MP) is developed. The mechanism of the CL reaction between Ag(III) complex {[Ag(HIO6)2]5−} and luminol in alkaline solution was proposed, along with the inhibition mechanism of 6-MP on the CL emission. The inhibition degree of CL emission was proportional to the logarithm of 6-MP concentration. The effects of the reaction conditions on CL emission and inhibition were examined. Under the optimized conditions, the detection limit (s/n=3) was 3.7×10−10 g ml−1. The recoveries of 6-MP were in the range of 97.7–105% with the RSD of 2.1–3.4% (n=5) for tablet samples, 103–106% with the RSDs of 1.1–2.1% for spiked serum sample, and 97.2–101% with the RSD of 2.0–4.5% for spiked urine sample. The accuracy of this method for the tablet analysis was examined by comparing with the pharmacopoeia method. The proposed method was used for the determination of 6-MP at clinically relevant concentrations in real urine and serum samples with satisfactory results. - Highlights: ► A sensitive inhibition chemiluminescence (CL) method for the determination of 6-MP is developed. ► The inhibition mechanism of 6-MP on the CL emission was proposed. ► The detection limit was 3.7×10−10 g ml−1. ► The accuracy was examined by comparing with the pharmacopoeia method.

  5. Study of Tl0(1) and In0(1) defects in alkaline halides: prototype of a color center as active laser medium

    International Nuclear Information System (INIS)

    The optical properties of the Tl0(1) and In0(1) centers in Kcl crystals in cation sites of the crystal lattice, perturbed by an adjacent anion vacancy. Emphasis is given to the lowest energy levels. Using a tagging optical absorption technique, the absorption bands were identified. The laser action of Tl0(1) center in KCl by pumping with Nd: YAG laser in the lowest energy absorption band was obtained. A simple way to achieve continuous single frequency laser operation using a grating as the sole tuning element is described. It is shown that, by proper choice of cavity parameters, the competing hole burning modes can be completely supressed. Experiments were carried out using Tl0(1) centers in KCl as the gain medium. The production of pulses via synchronous pumping of Tl0(1) color center in KCl are reported. (author)

  6. Substrate temperature study in the crystallinity of BaTiO{sub 3} thin films; Estudio de la temperatura de crecimiento sobre la cristalinidad en peliculas delgadas de BaTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Marquez-Herrera, Alfredo [Coordinacion Academica Region Altiplano (COARA), Universidad Autonoma de San Luis Potosi, San Luis Potosi (Mexico)]. E-mail: amarquez@mixteco.utm.mx; Hernandez-Rodriguez, Eric Noe; Zapata-Torres, Martin Guadalupe [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Instituto Politecnico Nacional (Mexico)]. E-mails: noehmx@hotmail.com; mzapatat@ipn.mx; Cruz-Jauregui, Maria de la Paz [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico (Mexico)]. E-mail: mcruz@cnyn.unam.mx; Melendez-Lira, Miguel angel [Centro de Investigacion y de Estudios Avanzados, Instituto Politecnico Nacional (Mexico)]. E-mail: mlira@fis.cinvestav.mx

    2013-07-15

    Ferroelectric thin films of BaTiO{sub 3} (BTO) were grown on quartz and nichrome substrates using a BaTiO{sub 3} target by RF-Sputtering technique. It was studied the effect of the substrate temperature in the crystallization of the material. These samples were compared with films deposited at room temperature and heat treated out of the growth Chamber. Their crystallinity were studied by X-ray diffraction. Additionally, the optical characterizations were carried out by UV-Vis spectrophotometer. The growth of thin films with substrate temperature allows the obtaining of crystalline materials at temperatures below those reported by other authors. [Spanish] Peliculas delgadas Ferroelectricas de BaTiO{sub 3} (BTO) se depositaron a partir de un blanco de BaTiO{sub 3} mediante la tecnica de RF-Sputtering (erosion catodica por radio frecuencia) sobre substratos de nicromel y cuarzo. Se estudio el efecto de la temperatura de sustrato in-situ en la cristalinidad del material durante su deposito. Estas muestras fueron comparadas con peliculas depositadas a temperatura ambiente y tratadas termicamente posterior al deposito fuera de la camara de crecimiento. El estudio de la cristalinidad fue realizado mediante la tecnica de difraccion de rayos-X. Adicionalmente, se llevaron a cabo caracterizaciones opticas mediante un espectrofotometro UV-Vis. El crecimiento de peliculas delgadas con temperatura de sustrato permite la obtencion de materiales cristalinos a temperaturas por debajo de las reportadas por otros autores.

  7. A study of substituent effect on the oxidative strengths of sodium salts of N-bromo-arylsulphonamides: Kinetics and mechanism of oxidation of D-fructose and D-glucose in alkaline medium

    Indian Academy of Sciences (India)

    K M Usha; B Thimme Gowda

    2006-07-01

    N-Bromo-arylsulphonamides of different oxidizing strengths are used for studying the kinetics of oxidation of D-fructose and D-glucose in aqueous alkaline medium. The results are analysed and compared with those from the sodium salts of N-bromo-benzenesulphonamide and N-bromo-4-methylbenzenesulphonamide. The reactions show zero-order kinetics in [oxidant], fractional order in [Fru/Glu] and nearly first order in [OH-]. Rates of oxidation of fructose are higher than those for glucose with the same oxidant. Similarly, values for glucose oxidations are higher than those for fructose. The results are explained by a suitable mechanism and the related rate law is deduced. The effective oxidising species in the reactions of N-bromo-arylsulphonamides is Br+. The oxidative strengths of the latter therefore depend on the ease with which Br+ is released from them. The ease with which Br+ is released from Nbromo- arylsulphonamides depends on the electron density on the nitrogen atom of the sulphonamide group, which in turn depends on the nature of the substituent on the benzene ring. The validity of the Hammett equation has also been tested for oxidation of both fructose and glucose. Enthalpies and entropies of activations of the oxidations by all the N-bromo-arylsulphonamides correlate well. The effect of substitution on and log of the oxidations is also considered.

  8. Growth of uniform lath-like {alpha}-(Fe,Al)OOH and disc-like {alpha}-(Fe,Al){sub 2}O{sub 3} nanoparticles in a highly alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Krehula, Stjepko, E-mail: krehul@irb.hr [Division of Materials Chemistry, Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Music, Svetozar [Division of Materials Chemistry, Ruder Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia)

    2010-09-01

    The effects of aluminium (Al{sup 3+})-dopant on the precipitation of uniform lath-like {alpha}-FeOOH particles, the obtention and growth of {alpha}-(Fe,Al)OOH and {alpha}-(Fe,Al){sub 2}O{sub 3} solid solutions, particle size and shape were investigated using X-ray powder diffraction, Moessbauer and Fourier transform infrared spectroscopies, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Acicular {alpha}-FeOOH particles, precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH), were used as reference material. The influence of Al-dopant was investigated by adding varying amounts of Al{sup 3+} ions to the initial FeCl{sub 3} solution. In the presence of lower concentrations of aluminium ions (up to 11.11 mol%) {alpha}-(Fe,Al)OOH as a single phase was formed, whereas higher concentrations led to an additional obtention and growth of {alpha}-(Fe,Al){sub 2}O{sub 3}. Al-for-Fe substitution in the {alpha}-FeOOH and {alpha}-Fe{sub 2}O{sub 3} structures was confirmed by a decrease in the unit-cell dimensions, a decrease in the hyperfine magnetic field and an increase in the wave number of the infrared absorption bands. The presence of lower concentrations of aluminium ions (up to 11.11 mol%) in the precipitation system did not affect the size and shape of the {alpha}-(Fe,Al)OOH particles, whereas higher concentrations influenced a decrease in the length and aspect ratio. In the presence of 42.86 mol% Al{sup 3+} ions fairly uniform disc-shaped {alpha}-(Fe,Al){sub 2}O{sub 3} were formed.

  9. Hidróxido de níquel suportado em carbono: um catalisador de baixo custo para a eletro-oxidação de alcoóis em meio alcalino Carbon supported nickel hydroxide: a low cost catalyst for alcohol electro-oxidation in alkaline medium

    OpenAIRE

    Marcelo Rodrigues da Silva; Antonio Carlos Dias Ângelo; Luiz Henrrique Dall'Antonia

    2010-01-01

    The present manuscript shows the synthesis of nickel hydroxide supported in carbon (Ni(OH)2/C) as a alternative material for catalytic alcohol oxidation in alkaline medium. The Ni(OH)2/C was synthesized in different percentage using a sonic bath. No current densities variation during successive cyclic voltammetry experiments was observed. The Ni(OH)2/C electrodes exhibit a potent and persistent electrocatalytic activity towards the oxidation of different alcohols. In addition, alcohols electo...

  10. ALP (Alkaline Phosphatase) Test

    Science.gov (United States)

    ... Also known as: ALK PHOS; Alkp Formal name: Alkaline Phosphatase Related tests: AST ; ALT ; GGT ; Bilirubin ; Liver Panel ; Bone Markers ; Alkaline Phosphatase Isoenzymes; Bone Specific ALP All content on ...

  11. Inlfuence of Mixed Alkali-Alkaline Earth Effect on Alkali Resistance of Medium Temperature Fritted Glaze%混合碱/碱土金属效应对中温熔块釉耐碱性的影响

    Institute of Scientific and Technical Information of China (English)

    秦立邦; 卢希龙; 曹春娥; 陈云霞; 沈华荣; 黄钢

    2014-01-01

    In order to improve the alkali resistance of medium temperature fritted glaze, a large number of experiments were carried out to get a better base fritted glaze. Then, inlfuence of mixed alkali metal effect and mixed alkaline earth metal effect on alkali resistance of the glaze was studied. Results show that mixed alkali effect existed in two alkali metal oxides-Li2O and Na2O. When the Li+/Na+molar ratio was equal to 1, the frit had the best alkali resistance. Calcium oxide had obvious suppression effect on alkali metal oxides. When the CaO/(Li2O+Na2O) molar ratio was equal to 1.22, the frit had the best alkali resistance. For binary mixed alkali metal oxides, when both the molar ratios of CaO/BaO and CaO/MgO were equal to 8.2, the frit had the best alkali resistance, but BaO worked better than MgO. For ternary mixed alkali metal oxides, when the molar ratio of CaO:MgO:BaO was equal to 14:3.3:1, both the frit and fritted glaze had the best alkali resistance.%为了提高中温熔块釉的耐碱性,通过大量实验得到较好的基础熔块釉组成,在此基础上,探讨混合碱金属效应、混合碱土金属效应对熔块耐碱性的影响。结果表明:Li2O和Na2O两种碱金属氧化物存在“混合碱金属效应”,其摩尔比为1时,熔块耐碱性最佳。氧化钙对碱金属(Li2O+Na2O)的压制效应明显,当CaO/(Li2O+Na2O)为1.22时,熔块耐碱性最好。二元碱土金属混合时,CaO/BaO、CaO/MgO摩尔比均为8.2时耐碱性最好,但BaO的效果要大于MgO;三元碱土混合中, CaO∶MgO∶BaO摩尔比为14∶3.3∶1时,熔块耐碱性最高,且此时釉的耐碱性也最强。

  12. 人羊膜移植联合自体角膜缘干细胞移植治疗中重度眼部碱烧伤%Amniotic Membrane Transplantation and Combination Stem Cell of Self-limbal Graft for Medium and Severe Ocular Alkaline Burn

    Institute of Scientific and Technical Information of China (English)

    丁明红; 李兴珍; 李成霞; 胡亚丽

    2001-01-01

    目的观察人羊膜移植联合自角膜缘干细胞移植治疗中重度眼部碱烧伤的临床效果。方法对8眼中重度眼部碱烧伤早期进行人羊膜移植联合自体角膜缘干细胞移植。结果 8眼中,7眼眼表面重建成功,4眼角膜透明,3眼角膜半透明,仅1眼发生轻度睑球粘连。结论人羊膜移植联合自体角膜缘干细胞移植治疗中重度眼部碱烧伤。对于重建眼表面,提高视功能,早期应用疗效较好。%ObjectiveTo observe the clinical effects of amniotic membrane transplantation and combination stem cell of self-limbal graft for medium and severe ocular alkaline burn.Methods 8 eyes in patients who had early medium or severe ocular alkaline burn were treated with amniotic membrane transplantation and ocular stem cell of self-limbal graft.Resulsts Among 8 eyes,the epithelia healed with stability without neovascularization in 7 eyes,there was corneal thansparency in 4 eyes,there was semitransparency in 3 eyes,and there was a little adhesion between eyetid and eyeball in 1 eye.Conclusion The clinical effects of amniotic membrane transplantation and combination stem cell of self-limbal graft for medium and severe ocular alkaline burn is satisfactory.

  13. Hidróxido de níquel suportado em carbono: um catalisador de baixo custo para a eletro-oxidação de alcoóis em meio alcalino Carbon supported nickel hydroxide: a low cost catalyst for alcohol electro-oxidation in alkaline medium

    Directory of Open Access Journals (Sweden)

    Marcelo Rodrigues da Silva

    2010-01-01

    Full Text Available The present manuscript shows the synthesis of nickel hydroxide supported in carbon (Ni(OH2/C as a alternative material for catalytic alcohol oxidation in alkaline medium. The Ni(OH2/C was synthesized in different percentage using a sonic bath. No current densities variation during successive cyclic voltammetry experiments was observed. The Ni(OH2/C electrodes exhibit a potent and persistent electrocatalytic activity towards the oxidation of different alcohols. In addition, alcohols electooxidation occurs in less positive potential compared with noble metal catalyst.

  14. Alkaline flocculation of Phaeodactylum tricornutum induced by brucite and calcite

    OpenAIRE

    Vandamme, Dries; Pohl, Philip I.; Beuckels, Annelies; Foubert, Imogen; Brady, Patrick V.; Hewson, John C.; Muylaert, Koenraad

    2015-01-01

    Alkaline flocculation holds great potential as a low-cost harvesting method for marine microalgae biomass production. Alkaline flocculation is induced by an increase in pH and is related to precipitation of calcium and magnesium salts. In this study, we used the diatom Phaeodactylum tricornutum as model organism to study alkaline flocculation of marine microalgae cultured in seawater medium. Flocculation started when pH was increased to 10 and flocculation efficiency reached 90% when pH was 1...

  15. Alkaline earth cation extraction from acid solution

    Science.gov (United States)

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  16. Absorbing materials of thin film for photovoltaic structures prepared by the process of pyrolytic spraying; Materiales absorbedores en pelicula delgada para estructuras fotovoltaicas preparados por el proceso de rocio pirolitico

    Energy Technology Data Exchange (ETDEWEB)

    Calixto Rodriguez, Manuela

    2006-11-15

    In this thesis work thin semiconducting films were grown with the following compounds: In{sub 2}S{sub 3}, Ag{sub 2}S, AgInS{sub 2}, SnS{sub 2} and SnS with the pyrolytic spray technique. The structural, optical and electrical proposals of these films were analyzed to determine the set of deposit parameters in which are obtained the physical properties for the applications of the same in photovoltaic structures. It was found that the molar relation in solution of the departing compounds and the deposit temperature are the same dominant parameters in the process of growing the films. For the deposit of thin films of Indio acetate were used and N, N-dimetil tiourea as precursory compounds of In and S, respectively. Polycrystalline films were obtained from the compound In{sub 2}S{sub 3} using underlying temperatures, Ts, between 400 and 450 degrees Celsius, and Indio acetate solutions and N, N-dimetil tiourea with molar relations (In:S) of 1:8 and 1:1. The energy breach, Eg, of these films varies from 2.04 to 2.67 eV, and the value of the conductivity in the darkness, D varies from 10-7 to 1(cm)-1 in function of the molar relation in solution. It was found that the deposited films using a molar relation of In:S=1:8 are of intrinsic nature independently of Ts, while the ones deposited using a molar relations of In:S=1:1 and Ts 400 degrees Celsius posses type-n conductivity. Using the molar relation of I:S=1:1 and Ts=500 degrees Celsius the compound polycrystalline of In{sub 2}O{sub 3} is obtained whose optical and electrical properties are Eg {approx} 3 eV and D=11 (cm)-1, with electrical conductivity type-n. The deposited films using a molar relation of In:S=1:1 and Ts=450 degrees Celsius are the ones that keep the appropriate characteristics for their use as type-n material in photovoltaic structures (Eg=2eV and D=1?-1 com-1). [Spanish] En este trabajo de tesis se crecieron peliculas delgadas semiconductoras de los compuestos: In{sub 2}S{sub 3}, Ag{sub 2}S, Ag

  17. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    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 10-3M) of sodium azide (NaN3) 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 M2

  18. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    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.

  19. 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 recyclability is…

  20. Reaction of dissolved ozone in hydrogen peroxide produced during ozonization of an alkaline medium in a bubble column - doi: 10.4025/actascitechnol.v36i1.11834

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Cremasco

    2014-01-01

    Full Text Available The effect of a reaction of dissolved ozone in an alkaline water solution with hydrogen peroxide was evaluated. Assays were conducted in a bubble column with a gaseous ozone concentration (mixed with oxygen at 21 and 27 g m-3. Concentration curve of dissolved ozone in the liquid revealed an ozone concentration peak in the liquid phase, subsequent decreasing concentration and constant maintenance in the stationary phase. Highest concentration was not detected for the lowest ozone concentration in the gaseous phase. Peak was due to the self-decomposition of ozone in the liquid phase and the production of hydrogen peroxide. The latter reacted with molecular dissolved ozone and decreased ozone concentration after maximum concentration.

  1. Alkaline battery operational methodology

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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.

  3. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    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

  4. Alkaline quinone flow battery.

    Science.gov (United States)

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy. PMID:26404834

  5. Alkaline broadening in Stars

    CERN Document Server

    De Kertanguy, A

    2015-01-01

    Giving new insight for line broadening theory for atoms with more structure than hydrogen in most stars. Using symbolic software to build precise wave functions corrected for ds;dp quantum defects. The profiles obtained with that approach, have peculiar trends, narrower than hydrogen, all quantum defects used are taken from atomic database topbase. Illustration of stronger effects of ions and electrons on the alkaline profiles, than neutral-neutral collision mechanism. Keywords : Stars: fundamental parameters - Atomic processes - Line: profiles.

  6. Alkaline quinone flow battery

    OpenAIRE

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise Ann; Valle, Alvaro West; Hardee, D.; Gordon, Roy Gerald; Aziz, Michael J.; Marshak, M

    2015-01-01

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe f...

  7. Measurement and calculation of dynamic coefficients in hydrodynamic bearings of gas films; Medicion y calculo de coeficientes dinamicos en cojinetes hidrodinamicos de peliculas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Rafael O.; Di Liscia, Marcelo H.; Diaz, Sergio E. [Universidad Simon Bolivar, Sartendejas, Baruta (Venezuela)

    2007-11-15

    dynamic coefficients. [Spanish] La identificacion de los coeficientes dinamicos en cojinetes de aire es fundamental para un adecuado analisis rotodinamico. El presente trabajo muestra el desarrollo de un algoritmo que permite la obtencion directa de los coeficientes dinamicos en cojinetes hidrodinamicos de aire tanto de forma numerica como experimental. El banco de pruebas utilizado consta de dos cojinetes magneticos, los cuales soportan al rotor en sus extremos y a su vez funcionan como actuadores permitiendo inducir orbitas controladas en el rotor. El cojinete de prueba se encuentra ubicado entre los cojinetes magneticos. Las fuerzas dinamicas generadas en el cojinete de aire se registran a partir de tres celdas de carga. El algoritmo fue desarrollado en un codigo comercial de programacion grafica, a traves del cual se pueden colectar, controlar y procesar las senales. El comportamiento no lineal de este tipo de cojinetes dificulta el calculo de los coeficientes dinamicos, por esta razon el procesamiento de las senales en espacio frecuencial facilita de cierta manera su manejo. Por otra parte, el modelo numerico se comparo con los resultados experimentales obteniendo aproximaciones aceptables tanto en magnitud como en comportamiento. El calculo de los coeficientes dinamicos numericos se realizo resolviendo la ecuacion diferencial de Reynolds para un fluido compresible en el espesor de la pelicula de gas, tomando en consideracion el flujo masico del fluido que se introduce, asi como la perdida de presion que sufre el mismo al pasar a traves de los orificios de alimentacion. Los metodos numericos utilizados incluyen la resolucion de la ecuacion diferencial de Reynolds por diferencias finitas, el calculo del perfil de presiones realizando iteraciones sucesivas y el calculo de las fuerzas hidrodinamicas a traves de una integracion numerica de Simpson. Los coeficientes dinamicos numericos fueron hallados aplicando una tecnica de minimos cuadrados a las fuerzas hidrodinamicas

  8. Alkaline Phosphatase in Stem Cells

    Directory of Open Access Journals (Sweden)

    Kateřina Štefková

    2015-01-01

    Full Text Available Alkaline phosphatase is an enzyme commonly expressed in almost all living organisms. In humans and other mammals, determinations of the expression and activity of alkaline phosphatase have frequently been used for cell determination in developmental studies and/or within clinical trials. Alkaline phosphatase also seems to be one of the key markers in the identification of pluripotent embryonic stem as well as related cells. However, alkaline phosphatases exist in some isoenzymes and isoforms, which have tissue specific expressions and functions. Here, the role of alkaline phosphatase as a stem cell marker is discussed in detail. First, we briefly summarize contemporary knowledge of mammalian alkaline phosphatases in general. Second, we focus on the known facts of its role in and potential significance for the identification of stem cells.

  9. 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.

  10. Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

    Science.gov (United States)

    Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  11. Bifunctional alkaline oxygen electrodes

    Science.gov (United States)

    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

  12. Silica in alkaline brines

    Science.gov (United States)

    Jones, B.F.; Rettig, S.L.; Eugster, H.P.

    1967-01-01

    Analysis of sodium carbonate-bicarbonate brines from closed basins in volcanic terranes of Oregon and Kenya reveals silica contents of up to 2700 parts per million at pH's higher than 10. These high concentrations of SiO 2 can be attributed to reaction of waters with silicates, and subsequent evaporative concentration accompanied by a rise in pH. Supersaturation with respect to amorphous silica may occur and persist for brines that are out of contact with silicate muds and undersaturated with respect to trona; correlation of SiO2 with concentration of Na and total CO2 support this interpretation. Addition of moredilute waters to alkaline brines may lower the pH and cause inorganic precipitation of substantial amounts of silica.

  13. Modulators of intestinal alkaline phosphatase.

    Science.gov (United States)

    Bobkova, Ekaterina V; Kiffer-Moreira, Tina; Sergienko, Eduard A

    2013-01-01

    Small molecule modulators of phosphatases can lead to clinically useful drugs and serve as invaluable tools to study functional roles of various phosphatases in vivo. Here, we describe lead discovery strategies for identification of inhibitors and activators of intestinal alkaline phosphatases. To identify isozyme-selective inhibitors and activators of the human and mouse intestinal alkaline phosphatases, ultrahigh throughput chemiluminescent assays, utilizing CDP-Star as a substrate, were developed for murine intestinal alkaline phosphatase (mIAP), human intestinal alkaline phosphatase (hIAP), human placental alkaline phosphatase (PLAP), and human tissue-nonspecific alkaline phosphatase (TNAP) isozymes. Using these 1,536-well assays, concurrent HTS screens of the MLSMR library of 323,000 compounds were conducted for human and mouse IAP isozymes monitoring both inhibition and activation. This parallel screening approach led to identification of a novel inhibitory scaffold selective for murine intestinal alkaline phosphatase. SAR efforts based on parallel testing of analogs against different AP isozymes generated a potent inhibitor of the murine IAP with IC50 of 540 nM, at least 65-fold selectivity against human TNAP, and >185 selectivity against human PLAP. PMID:23860652

  14. Alkaline battery, separator therefore

    Science.gov (United States)

    Schmidt, George F. (Inventor)

    1980-01-01

    An improved battery separator for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The separator is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in separator coatings. When the separator is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.

  15. Studies on Fast Remediation of Soda Meadow Alkaline Soil

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lianren; SUN Yankun; LI Dawei

    2010-01-01

    Researches on models of remediation quickly in soda meadow alkaline soil, and dynamic variation of water-salt in saline soil of Zhaozhou County were studied systematically from 2001 to 2006. Realize the vegetation cover of those years through the artificial planting, mixed seeding lymc grass (Elymus dahuricus Turcz) and melilot in the mode of rotary tillage and deep loosening in lower and medium saline soils. The results showed that there was remarkable relationship between net evaporation (difference of precipitation and evaporation) and total salt content in the soil. The net evaporation could be used as a new method to forecast the dynamics variation of salt to ensure the pasture optimum sowing time. Realize the autumnal vegetation cover of those years through direct planting on the bourgeon layer of soda meadow alkaline soil, on the other hand, the covered pasture made the function of restraining salt and alkaline content to realize the biology reverse succession quickly. Forage seeds were seeded directly on the seeding bed of soda alkaline meadow at the end of July. In fall of the same year, a certain amount of biomass was obtained. The model, which has remarkable economical efficiency and use widely, represented the innovative model for the fast vegetation restoration on the soda alkaline meadow soil.

  16. Characterization of Human Bone Alkaline Phosphatase in Pichia Pastoris

    Science.gov (United States)

    Malone, Christine C.; Ciszak, Eva; Karr, Laurel J.

    1999-01-01

    A soluble form of human bone alkaline phosphatase has been expressed in a recombinant strain of the methylotrophic yeast Pichia pastoris. We constructed a plasmid containing cDNA encoding for human bone alkaline phosphatase, with the hydrophobic carboxyl terminal portion deleted. Alkaline phosphatase was secreted into the medium to a level of 32mg/L when cultured in shake flasks, and enzyme activity was 12U/mg, as measured by a spectrophotometric assay. By conversion to a fermentation system, a yield of 880mg/L has been achieved with an enzyme activity of 968U/mg. By gel electrophoresis analysis, it appears that greater than 50% of the total protein in the fermentation media is alkaline phosphatase. Although purification procedures are not yet completely optimized, they are expected to include filtration, ion exchange and affinity chromatography. Our presentation will focus on the purification and crystallization results up to the time of the conference. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  17. The alkaline and alkaline-carbonatite magmatism from Southern Brazil

    Science.gov (United States)

    Ruberti, E.; Gomes, C. D. B.; Comin-Chiaramonti, P.

    2015-12-01

    Early to Late Cretaceous lasting to Paleocene alkaline magmatism from southern Brazil is found associated with major extensional structural features in and around the Paraná Basin and grouped into various provinces on the basis of several data. Magmatism is variable in size, mode of occurrence and composition. The alkaline rocks are dominantly potassic, a few occurrences showing sodic affinity. The more abundant silicate rocks are evolved undersaturated to saturated in silica syenites, displaying large variation in igneous forms. Less evolved types are restricted to subvolcanic environments and outcrops of effusive suites occur rarely. Cumulatic mafic and ultramafic rock types are very common, particularly in the alkali-carbonatitic complexes. Carbonatite bodies are represented by Ca-carbonatites and Mg-carbonatites and more scarcely by Fe-carbonatites. Available radiometric ages for the alkaline rocks fit on three main chronological groups: around 130 Ma, subcoveal with the Early Cretaceous flood tholeiites of the Paraná Basin, 100-110 Ma and 80-90 Ma (Late Cretaceous). The alkaline magmatism also extends into Paleocene times, as indicated by ages from some volcanic lavas. Geochemically, alkaline potassic and sodic rock types are distinguished by their negative and positive Nb-Ta anomalies, respectively. Negative spikes in Nb-Ta are also a feature common to the associated tholeiitic rocks. Sr-Nd-Pb systematics confirm the contribution of both HIMU and EMI mantle components in the formation of the alkaline rocks. Notably, Early and Late Cretaceous carbonatites have the same isotopic Sr-Nd initial ratios of the associated alkaline rocks. C-O isotopic Sr-Nd isotopic ratios indicate typical mantle signature for some carbonatites and the influence of post-magmatic processes in others. Immiscibility of liquids of phonolitic composition, derived from mafic alkaline parental magmas, has been responsible for the origin of the carbonatites. Close association of alkaline

  18. Carbon nanotubes-gold nanohybrid as potent electrocatalyst for oxygen reduction in alkaline media.

    Science.gov (United States)

    Morozan, Adina; Donck, Simon; Artero, Vincent; Gravel, Edmond; Doris, Eric

    2015-11-01

    A carbon nanotube-gold nanohybrid was used as catalyst for the reduction of molecular oxygen in acidic and alkaline media, the relevant cathode reaction in fuel cells. In alkaline medium, the nanohybrid exhibits excellent activity with a dominant 4e(-) reduction of O2 and low overpotential requirement compared to previously reported nano-gold materials. This property is linked to its capability to efficiently mediate HO2(-) dismutation. PMID:26439282

  19. Production of Alkaline Cellulase by Fungi Isolated from an Undisturbed Rain Forest of Peru

    OpenAIRE

    Karin Vega; Gretty K. Villena; Sarmiento, Victor H.; Yvette Ludeña; Nadia Vera; Marcel Gutiérrez-Correa

    2012-01-01

    Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an ap...

  20. Formation of magnetite in highly alkaline media in the presence of small amounts of ruthenium

    OpenAIRE

    Krehula, Stjepko; Musić, Svetozar

    2007-01-01

    The effect of small amounts of ruthenium on the formation of magnetite in highly alkaline media was investigated using X-ray powder diffraction (XRD), Mossbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Acicular alpha-FeOOH particles precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as a reference material. Initial addition of small amounts of Ru(NO)(...

  1. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank; Mogensen, Mogens Bjerg; Møller, Per; Hilbert, Lisbeth R.; Nielsen, Peter Tommy; Mathiesen, Troels; Jensen, Jørgen; Andersen, Lars; Dierking, Alexander

    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...

  2. Transcriptome Analysis of Enterococcus faecalis in Response to Alkaline Stress

    Directory of Open Access Journals (Sweden)

    Ran eshujun

    2015-08-01

    Full Text Available E. faecalis is the most commonly isolated species from endodontic failure root canals; its persistence in treated root canals has been attributed to its ability to resist high pH stress. The goal of this study was to characterize the E. faecalis transcriptome and to identify candidate genes for response and resistance to alkaline stress using Illumina HiSeq 2000 sequencing.We found that E. faecalis could survive and form biofilms in a pH 10 environment and that alkaline stress had a great impact on the transcription of many genes in the E. faecalis genome. The transcriptome sequencing results revealed that 613 genes were differentially expressed (DEGs for E. faecalis grown in pH 10 medium; 211 genes were found to be differentially up-regulated and 402 genes differentially down-regulated. Many of the down-regulated genes found are involved in cell energy production and metabolism and carbohydrate and amino acid metabolism, and the up-regulated genes are mostly related to nucleotide transport and metabolism. The results presented here reveal that cultivation of E. faecalis in alkaline stress has a profound impact on its transcriptome. The observed regulation of genes and pathways revealed that E. faecalis reduced its carbohydrate and amino acid metabolism and increased nucleotide synthesis to adapt and grow in alkaline stress. A number of the regulated genes may be useful candidates for the development of new therapeutic approaches for the treatment of E. faecalis infections.

  3. Alkaline Protease Production by a Strain of Marine Yeasts

    Institute of Scientific and Technical Information of China (English)

    WANG Ping; CHI Zhenming; MA Chunling

    2006-01-01

    Yeast strain 10 with high yield of protease was isolated from sediments of saltern near Qingdao, China.The protease had the highest activity at pH 9.0 and 45 ℃.The optimal medium for the maximum alkaline protease production of strain 10 was 2.5 g soluble starch and 2.0 g NaNO3 in 100 mL seawater with initial pH6.0.The optimal cultivation conditions for the maximum protease production were temperature 24.5 ℃, aeration rate 8.0 L min -1 and agitation speed 150 r min-1.Under the optimal conditions, 623.1 Umg-1 protein of alkaline protease was reached in the culture within 30 h of fermentation.

  4. Development of alkaline fuel cells.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari [Colorado School of Mines, Golden, CO; Horan, James L. [Colorado School of Mines, Golden, CO; Caire, Benjamin R. [Colorado School of Mines, Golden, CO; Ziegler, Zachary C. [Colorado School of Mines, Golden, CO; Herring, Andrew M. [Colorado School of Mines, Golden, CO; Yang, Yuan [Colorado School of Mines, Golden, CO; Zuo, Xiaobing [Argonne National Laboratory, Argonne, IL; Robson, Michael H. [University of New Mexico, Albuquerque, NM; Artyushkova, Kateryna [University of New Mexico, Albuquerque, NM; Patterson, Wendy [University of New Mexico, Albuquerque, NM; Atanassov, Plamen Borissov [University of New Mexico, Albuquerque, NM

    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 Atanassov's research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herring's 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.

  5. Influence of Oil Viscosity on Alkaline Flooding for Enhanced Heavy Oil Recovery

    Directory of Open Access Journals (Sweden)

    Yong Du

    2013-01-01

    Full Text Available Oil viscosity was studied as an important factor for alkaline flooding based on the mechanism of “water drops” flow. Alkaline flooding for two oil samples with different viscosities but similar acid numbers was compared. Besides, series flooding tests for the same oil sample were conducted at different temperatures and permeabilities. The results of flooding tests indicated that a high tertiary oil recovery could be achieved only in the low-permeability (approximately 500 mD sandpacks for the low-viscosity heavy oil (Zhuangxi, 390 mPa·s; however, the high-viscosity heavy oil (Chenzhuang, 3450 mPa·s performed well in both the low- and medium-permeability (approximately 1000 mD sandpacks. In addition, the results of flooding tests for the same oil at different temperatures also indicated that the oil viscosity put a similar effect on alkaline flooding. Therefore, oil with a high-viscosity is favorable for alkaline flooding. The microscopic flooding test indicated that the water drops produced during alkaline flooding for oils with different viscosities differed significantly in their sizes, which might influence the flow behaviors and therefore the sweep efficiencies of alkaline fluids. This study provides an evidence for the feasibility of the development of high-viscosity heavy oil using alkaline flooding.

  6. Characterization of an Aspergillus flavus alkaline protease and its role in the infection of maize kernels

    Science.gov (United States)

    A 33 kDa protein present in Aspergillus flavus infected maize embryo tissue was identified as a fungal alkaline protease (ALP). This protein became one of the major extracellular proteins of A. flavus in potato dextrose broth medium cultural filtrate after 3 days, but was expressed at low levels or ...

  7. Influence of salivary enzymes and alkaline pH environment on fatigue behavior of resin composites

    NARCIS (Netherlands)

    H. Mirmohammadi; C.J. Kleverlaan; M.N. Aboushelib; A.J. Feilzer

    2011-01-01

    Purpose: To evaluate the effect of enzymatic activity and alkaline medium on flexural strength and rotary fatigue resistance of direct and indirect resin composite restorative materials. Methods: Three direct resin composite materials Filtek Z100, Filtek Z250 and Filtek Silorane (3M ESPE), and two i

  8. Measurement of respiratory CO2 production of roots in an aquatic medium

    International Nuclear Information System (INIS)

    Changes in pH, total alkalinity and O2 concentration were followed in an aquatic medium with excised wheat roots (Tritkum aestivum L.). Concentrations of total inorganic carbon and free CO2 were calculated from total alkalinity and pH according to carbonate equilibria. The total inorganic carbon was estimated by flow-injection infra-red gas analysis. Total alkalinity increased in the root medium during incubation. Respiratory CO2 production was estimated best from the increase in total inorganic carbon measured with an infra-red gas analyser

  9. Alkaline fuel cell performance investigation

    Science.gov (United States)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more that two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  10. Solvent extraction of dibutylphosphate bearing alkaline wastes from purex process

    International Nuclear Information System (INIS)

    In the Purex process tributylphosphate undergoes chemical and radiolytic attack leading to the formation of acidic degradation products, mainly dibutylphosphate (DBP) and to a lesser extent monobutylphosphate (MBP). These alkylphosphoric compounds are extractants and may also give insoluble complexes with several cations of fission products. Thus their elimination from the organic phase by alkaline scrubbing of the solvent is necessary. The alkaline solution is generally made of carbonate, in order to keep uranium and plutonium, which can be present in small quantities, under a soluble form. The destination of this aqueous solution is usually the high or the medium activity wastes. Recycling actinide values from these effluent solutions in the process is to be considered to lower alpha-activity in the wastes. In this paper is studied the tri-iso-octylamine for extracting the disturbing organophosphorous compounds from neutral or alkaline solutions where they are under an anionic form. The actinides will stay in these aqueous solutions which can be concentrated and recycled without any risk of precipitation

  11. Alkaline flocculation of Phaeodactylum tricornutum induced by brucite and calcite.

    Science.gov (United States)

    Vandamme, Dries; Pohl, Philip I; Beuckels, Annelies; Foubert, Imogen; Brady, Patrick V; Hewson, John C; Muylaert, Koenraad

    2015-11-01

    Alkaline flocculation holds great potential as a low-cost harvesting method for marine microalgae biomass production. Alkaline flocculation is induced by an increase in pH and is related to precipitation of calcium and magnesium salts. In this study, we used the diatom Phaeodactylum tricornutum as model organism to study alkaline flocculation of marine microalgae cultured in seawater medium. Flocculation started when pH was increased to 10 and flocculation efficiency reached 90% when pH was 10.5, which was consistent with precipitation modeling for brucite or Mg(OH)2. Compared to freshwater species, more magnesium is needed to achieve flocculation (>7.5mM). Zeta potential measurements suggest that brucite precipitation caused flocculation by charge neutralization. When calcium concentration was 12.5mM, flocculation was also observed at a pH of 10. Zeta potential remained negative up to pH 11.5, suggesting that precipitated calcite caused flocculation by a sweeping coagulation mechanism. PMID:26310384

  12. Grace DAKASEP alkaline battery separator

    Science.gov (United States)

    Giovannoni, R. T.; Lundquist, J. T.; Choi, W. M.

    1987-01-01

    The Grace DAKASEP separator was originally developed as a wicking layer for nickel-zinc alkaline batteries. The DAKASEP is a filled non-woven separator which is flexible and heat sealable. Through modification of formulation and processing variables, products with a variety of properties can be produced. Variations of DAKASEP were tested in Ni-H2, Ni-Zn, Ni-Cd, and primary alkaline batteries with good results. The properties of DAKASEP which are optimized for Hg-Zn primary batteries are shown in tabular form. This separator has high tensile strength, 12 micron average pore size, relatively low porosity at 46-48 percent, and consequently moderately high resistivity. Versions were produced with greater than 70 percent porosity and resistivities in 33 wt percent KOH as low as 3 ohm cm. Performance data for Hg-Zn E-1 size cells containing DAKASEP with the properties shown in tabular form, are more reproducible than data obtained with a competitive polypropylene non-woven separator. In addition, utilization of active material is in general considerably improved.

  13. 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.

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

    International Nuclear Information System (INIS)

    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)

  15. Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease.

    Directory of Open Access Journals (Sweden)

    Hongxia Cui

    Full Text Available While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production.

  16. Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease.

    Science.gov (United States)

    Cui, Hongxia; Yang, Muyang; Wang, Liping; Xian, Cory J

    2015-01-01

    While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production. PMID:26716833

  17. Behaviour of alkaline cement mortars reinforced with acrylic and polypropylene fibres

    OpenAIRE

    Puertas, P.; Amat, T.; Vázquez, T.

    2000-01-01

    In the present work, the behaviour of alkaline cement mortars reinforced with fibres of different nature (acrylic and polypropylene fibres) is studied. Also the chemical stability of those fibres in strong alkaline medium has been investigated. Three different matrixes have been used: glass blast furnace slag activated with NaOH 2M (room temperature, 22 ºC); fly ash activated with NaOH 8M, cured at 85ºC during 24 hours and 50% fly ash / 50% slag activated with NaOH 8M, room temperature. The f...

  18. Broth medium for enrichment of Vibrio fluvialis from the environment.

    OpenAIRE

    Nishibuchi, M; Roberts, N C; Bradford, H B; Seidler, R J

    1983-01-01

    A medium was designed for the enrichment and enumeration of Vibrio fluvialis from environmental samples. The medium contains 1% peptone plus 4% sodium chloride and 5 micrograms of novobiocin per ml, pH 8.5. This V. fluvialis enrichment medium (FEM) was tested, in comparison with alkaline peptone (AP), in field samplings. A total of 177 samples (estuarine waters and sediment, sewage, and crabs) collected over a 14-month period were examined with FEM and with AP broth. Results showed that FEM w...

  19. Optimization and partial characterization of culture conditions for the production of alkaline protease from Bacillus licheniformis P003

    OpenAIRE

    Sarker, Palash Kumar; Talukdar, Saimon Ahmad; Deb, Promita; Sayem, SM Abu; Mohsina, Kaniz

    2013-01-01

    Proteolytic enzymes have occupied a pivotal position for their practical applications. The present study was carried out under shake flask conditions for the production of alkaline protease from Bacillus licheniformis P003 in basal medium containing glucose, peptone, K2HPO4, MgSO4 and Na2CO3 at pH 10. The effect of culture conditions and medium components for maximum production of alkaline protease was investigated using one factor constant at a time method along with its characterization. Ma...

  20. In vitro alkaline pH resistance of Enterococcus faecalis.

    Science.gov (United States)

    Weckwerth, Paulo Henrique; Zapata, Ronald Ordinola; Vivan, Rodrigo Ricci; Tanomaru Filho, Mário; Maliza, Amanda Garcia Alves; Duarte, Marco Antonio Hungaro

    2013-01-01

    Enterococcus faecalis is a bacterial species often found in root canals with failed endodontic treatment. Alkaline pastes are widely used in Endodontics because of their biocompatibility and antimicrobial activity, but this microorganism can resist alkalinity. The purpose of this study was to evaluate in vitro the alkaline pH resistance of E. faecalis for different periods up to 14 days. Samples were obtained from the oral cavity of 150 patients from the Endodontic clinic. The pH of the experimental tubes (n=84) was first adjusted with 6M NaOH to pH values of 9.5, 10.5, 11.5 and 12.5 (21 tubes per pH). Twenty clinical isolates and the ATCC 29212 strain were tested. The 5 positive controls and experimental tubes of each pH were inoculated with 10 µL of bacterial suspension and incubated at 36 °C for 24, 48 and 72 h, 7 and 14 days. For each period, the turbidity of the medium was visually compared with a 0.5 McFarland standard. The presence of the microorganism was confirmed by seeding on M-Enterococcus agar. Four tubes containing BHI broth adjusted to the tested pHs were incubated for 14 days to verify if pH changes occurred. The pH of inoculated BHI broth was also measured on day 14 to determine if the microorganism acidified the medium. The growth of all E. faecalis strains occurred at pH 9.5 to 11.5 in all periods. Although turbidity was not observed at pH 12.5, there was growth of 13 and 2 strains at 24 and 48 h, respectively, on M-Enterococcus agar. No tube showed growth at pH 12.5 after 72 h. It was concluded that E. faecalis can survive in highly alkaline pH, and some clinical isolates require 72 h at pH 12.5 to be killed. PMID:24474287

  1. Alkaline sorbent injection for mercury control

    Science.gov (United States)

    Madden, Deborah A.; Holmes, Michael J.

    2003-01-01

    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.

  2. Alkaline rocks and the occurrence of uranium

    International Nuclear Information System (INIS)

    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

  3. TiO{sub 2} obtained by laser ablation and it response in alkaline medium for the oxygen detachment reaction; TiO{sub 2} obtenido por ablacion laser y su respuesta en medio alcalino para la reaccion de desprendimiento de oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez B, J.; Escobar A, L.; Fernandez V, S.M. [ININ, 52750 La Marquesa, Ocoyoacac (Mexico)]. e-mail: jjb@nuclear.inin.mx

    2007-07-01

    The performance of the photo electrocatalysts materials depends on one hand of the it structures of the crystalline lattice and of their surface properties, those which in turn are determined by the material preparation method. In this work the laser ablation technique to obtain thin films of titanium dioxide on recovered glass with tin oxide is presented. The carried out analyses showed homogeneous films, one of amorphous titanium oxide with a band width of 3.43 eV and the other one with anatase structure with a band energy of 3.41 eV. The photoresponse for the oxygen detachment it was better for the anatase. In a 0.1M KOH medium it was found corrosion in the films. (Author)

  4. Alkalinity in oil field waters - what alkalinity is and how it is measured

    International Nuclear Information System (INIS)

    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

  5. Heterologous expression, biochemical characterization, and overproduction of alkaline α-amylase from Bacillus alcalophilus in Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Li Jianghua

    2011-10-01

    Full Text Available Abstract Background Alkaline α-amylases have potential applications for hydrolyzing starch under high pH conditions in the starch and textile industries and as ingredients in detergents for automatic dishwashers and laundries. While the alkaline α-amylase gains increased industrial interest, the yield of alkaline α-amylases from wild-type microbes is low, and the combination of genetic engineering and process optimization is necessary to achieve the overproduction of alkaline α-amylase. Results The alkaline α-amylase gene from Bacillus alcalophilus JN21 (CCTCC NO. M 2011229 was cloned and expressed in Bacillus subtilis strain WB600 with vector pMA5. The recombinant alkaline α-amylase was stable at pH from 7.0 to 11.0 and temperature below 40°C. The optimum pH and temperature of alkaline α-amylase was 9.0 and 50°C, respectively. Using soluble starch as the substrate, the Km and Vmax of alkaline α-amylase were 9.64 g/L and 0.80 g/(L·min, respectively. The effects of medium compositions (starch, peptone, and soybean meal and temperature on the recombinant production of alkaline α-amylase in B. subtilis were investigated. Under the optimal conditions (starch concentration 0.6% (w/v, peptone concentration 1.45% (w/v, soybean meal concentration 1.3% (w/v, and temperature 37°C, the highest yield of alkaline α-amylase reached 415 U/mL. The yield of alkaline α-amylase in a 3-L fermentor reached 441 U/mL, which was 79 times that of native alkaline α-amylase from B. alcalophilus JN21. Conclusions This is the first report concerning the heterologous expression of alkaline α-amylase in B. subtilis, and the obtained results make it feasible to achieve the industrial production of alkaline α-amylase with the recombinant B. subtilis.

  6. Technetium recovery from high alkaline solution

    Science.gov (United States)

    Nash, Charles A.

    2016-07-12

    Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

  7. Alkaline tolerant dextranase from streptomyces anulatus

    Science.gov (United States)

    Decker, Stephen R.; Adney, William S.; Vinzant, Todd B.; Himmel, Michael E.

    2003-01-01

    A process for production of an alkaline tolerant dextranase enzyme comprises culturing a dextran-producing microorganism Streptomyces anulatus having accession no. ATCC PTA-3866 to produce an alkaline tolerant dextranase, Dex 1 wherein the protein in said enzyme is characterized by a MW of 63.3 kDa and Dex 2 wherein its protein is characterized by a MW of 81.8 kDa.

  8. Alkaline Water and Longevity: A Murine Study

    Science.gov (United States)

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models. PMID:27340414

  9. Hydration of Hybrid Alkaline Cement Containing a Very Large Proportion of Fly Ash: A Descriptive Model

    Directory of Open Access Journals (Sweden)

    Inés Garcia-Lodeiro

    2016-07-01

    Full Text Available In hybrid alkaline fly ash cements, a new generation of binders, hydration, is characterized by features found in both ordinary portland cement (OPC hydration and the alkali activation of fly ash (AAFA. Hybrid alkaline fly ash cements typically have a high fly ash (70 wt % to 80 wt % and low clinker (20 wt % to 30 wt % content. The clinker component favors curing at ambient temperature. A hydration mechanism is proposed based on the authors’ research on these hybrid binders over the last five years. The mechanisms for OPC hydration and FA alkaline activation are summarized by way of reference. In hybrid systems, fly ash activity is visible at very early ages, when two types of gel are formed: C–S–H from the OPC and N–A–S–H from the fly ash. In their mutual presence, these gels tend to evolve, respectively, into C–A–S–H and (N,C–A–S–H. The use of activators with different degrees of alkalinity has a direct impact on reaction kinetics but does not modify the main final products, a mixture of C–A–S–H and (N,C–A–S–H gels. The proportion of each gel in the mix does, however, depend on the alkalinity generated in the medium.

  10. Production of Alkaline Cellulase by Fungi Isolated from an Undisturbed Rain Forest of Peru

    Directory of Open Access Journals (Sweden)

    Karin Vega

    2012-01-01

    Full Text Available Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL−1 with higher specific productivities (>30 U g−1 h−1. Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry.

  11. Stability and selectivity of alkaline proteases in hydrophilic solvents

    DEFF Research Database (Denmark)

    Pedersen, Lars Haastrup; Ritthitham, Sinthuwat; Pleissner, Daniel

    2008-01-01

    substitution. Some of the most abundant hexoses were all substituted at the primary hydroxyl group at the C-6 position in processes catalysed by different alkaline proteases [3,4,5]. However by adding DMSO to the reaction medium the regio-selectivity in a Streptomyces sp protease catalysed reaction was shifted...... was 10 minutes. The activity was effected by the solvation of the enzyme in both DMSO and DMF [11]. Literature   [1]           H. Ogino, H. Ishikawa, J. Biosci. Bioeng. 2001, 91, 109. [2]           K. Watanabe, S. Ueji, Biotechnol. Lett. 2000, 22, 599. {3]           M. Kitagawa, H. Fan, T. Raku, S...

  12. Key role of alkaline phosphatase for development of human-derived nanoparticles in vitro

    OpenAIRE

    Hunter, Larry W.; Shiekh, Farooq A; Pisimisis, George T.; Kim, Sung-Hoon; Edeh, Samuel N.; Miller, Virginia M.; Lieske, John C.

    2010-01-01

    Alkaline phosphatase (ALP) is an enzyme critical for physiological and pathological biomineralization. Experiments were designed to determine if ALP participates in formation of calcifying nanometer-sized particles (NPs) in vitro. Filtered homogenates of human calcified carotid artery, aorta and kidney stones were inoculated into cell culture medium containing 10% fetal bovine serum in the absence or presence of inhibitors of ALP or pyrophosphate. Calcific NP biofilm developed within one week...

  13. 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...

  14. Production of extracellular alkaline protease from Bacillus subtilis RSKK96 with solid state fermentation

    Directory of Open Access Journals (Sweden)

    Nurullah Akcan

    2011-09-01

    Full Text Available The production of extracellular alkaline protease by producing Bacillus subtilis RSKK96 was studied with solid state fermentation (SSF. Different agro residues as substrate were studied for enzyme production. The highest enzyme production was expressed with lentil husk as units per mass of dry substrate (3937.0 U/mg. Production parameters were optimized as incubation time 120 h, extraction medium Triton-X100 1%, initial moisture content 30%, initial pH 9.0. The high level of alkaline protease was obtained in the medium containing arabinose followed by lactose, galactose, and fructose. Among various nitrogen sources, beef extract was found to be the best inducer of alkaline protease, while other nitrogen sources repressed enzyme production. Among metal salts FeSO4.7H2O and MgSO4.7H2O was found to increase protease production. The maximum enzyme production (5759.2 U/mg was observed with lentil husk in 1000 mL of fermentation medium volume.

  15. Chromatographic transport of alkaline buffers through reservoir rock

    International Nuclear Information System (INIS)

    Use of relatively low-pH alkaline buffers, such as sodium carbonate or sodium silicate, is explored as a means for overcoming sodium/hydrogen ion-exchange delay in alkaline waterflooding. A local-equilibrium chromatographic model is outlined to describe the concentration velocities for injection of alkaline buffers into a linear porous medium that exhibits reversible sodium/hydrogen exchange. The theory predicts a buffer ion-exchange wave that is substantially faster than that for equivalent-pH sodium hydroxide solutions. New experimental displacement data are presented for NaOH over a pH range from 11 to 13 and for 0.1, 0.5, and 1.0 wt% Na/sub 2/CO/sub 3/ flowing through a 1 wt% NaCl brine saturated Berea sandstone core at 500C [1220F]. To permit a complete description of the system, column effluent concentrations are measured for sodium ions, hydroxide ions, H/sup 3/-tagged water, and /sup 14/C-tagged carbonate. The experiments confirm that Na/sub 2/CO/sub 3/ propagates through the Berea sand at a higher rate than NaOH. For example, at pH=11.4, Na/sub 2/CO/sub 3/ migrates with a velocity that is 3.5 times faster than NaOH. Comparison of experiment with the ion-exchange chromatography theory shows good agreement. The authors successfully model the concentration histories of tritium-labeled water, total carbon, sodium, and hydroxide, all with no adjustable parameters. This work establishes with both theory and experiment that buffered alkali significantly increases the propagation speed of hydroxide in reservoir sands in comparison with unbuffered alkali at equivalent sodium and hydroxide concentrations. Because lower-pH buffered alkali can also protect against rock dissolution loss, the validated reduction of buffer ion-exchange lag considerably improves the promise of the alkaline flooding process for field application

  16. 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

    2012-01-01

    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

  17. Hadrons in medium

    Indian Academy of Sciences (India)

    U Mosel

    2006-04-01

    In these lectures I first give the motivation for investigations of in-medium properties of hadrons. I discuss the relevant symmetries of QCD and how they might affect the observed hadron properties. I then discuss at length the observable consequences of in-medium changes of hadronic properties in reactions with elementary probes, and in particular photons, on nuclei. Here I put an emphasis on new experiments on changes of the - and -mesons in medium.

  18. pH recovery from intracellular alkalinization in Retzius neurones of the leech central nervous system.

    Science.gov (United States)

    Frey, G; Schlue, W R

    1993-03-01

    1. Neutral-carrier pH-sensitive microelectrodes were used to investigate intracellular pH (pHi) recovery from alkalinization in leech Retzius neurones in Hepes- and in CO2-HCO3(-)-buffered solution. The Retzius neurones were alkaline loaded by the addition and subsequent removal of 16 mM acetate, by changing from 5% CO2-27 mM HCO3- to 2% CO2-11 mM HCO3- or by changing from CO2-HCO3(-)- to Hepes-buffered solution. 2. In Hepes-buffered solution (pH 7.4) the mean pHi was 7.29 +/- 0.11 and the mean membrane potential -44.7 +/- 5.9 mV (mean +/- S.D.; n = 83). 3. The rate of pHi recovery from alkalinization increased with decreasing pH of the bathing medium (pHb). pHi changed about 0.30 pH units for a pHb unit change. 4. A decrease of extracellular buffer concentration (Hepes concentration lowered from 20 to 5 mM) caused an acidification of extracellular and intracellular pH and an acceleration of pHi recovery from alkalinization. 5. A depolarization of the Retzius cell membrane-induced by increasing the K+ concentration of the bathing medium from 4 to 20 mM (delta Em = 16.5 +/- 5.5 mV) or from 4 to 40 mM (delta Em = 24.8 +/- 3.5 mV)--evoked a decrease of pHi and an acceleration of pHi recovery from alkalinization. 6. The H+ current blocker Zn2+ (0.5 mM) inhibited pHi recovery from alkalinization at resting membrane potential as well as during depolarization. The inhibition was more pronounced during depolarization. 7. In Cl(-)-free, CO2-HCO3(-)-buffered solution pHi recovery from an alkaline load by changing from 5% CO2-27 mM HCO3- to 2% CO2-11 mM HCO3- was slowed by 48-71%. The rate of pHi recovery from an alkaline load induced by changing from CO2-HCO3- to Hepes buffer was reduced by 33-56% in Cl(-)-free solution. The removal of external Cl- did not affect pHi recovery in Hepes-buffered solution. 8. The pHi recovery from alkalinization was DIDS-insensitive in CO2-HCO3(-)- as in Hepes-buffered solutions and was not slowed in the absence of external Na+. 9. It is

  19. Specific Examples of Hybrid Alkaline Cement

    OpenAIRE

    Fernández-Jiménez Ana; García-Lodeiro Inés; Donatello Shane; Maltseva Olga; Palomo Ángel

    2014-01-01

    Hybrid alkaline cements are obtained by alkali-activating cementitious blends in the Na2O-CaO-SiO2-Al2O3-H2O system. The present paper discusses the results of activating different cementitious blends containing a low OPC clinker content ( 15MPa a 2 days) different alkaline activators were used (liquid and solid). The reaction products obtained were also characterised by XRD, SEM/EDX and 27Al and 29Si NMRMAS. The results showed that the main reaction product was a mix of cementitious gels C-A...

  20. 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.

  1. Alkaline Capacitors Based on Nitride Nanoparticles

    Science.gov (United States)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  2. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    C L Aravinda; S M Mayanna; V R Muralidharan

    2000-10-01

    A search for non-cyanide plating baths for copper resulted in the development of alkaline copper complex baths containing trisodium citrate [TSC] and triethanolamine [TEA]. Voltammetric studies were carried out on platinum to understand the electrochemical behaviour of these complexes. In TSC solutions, the deposition of copper involves the slow formation of a monovalent species. Adsorption of this species obeys Langmuir isotherm. In TEA solutions the deposition involves the formation of monovalent ions obeying the non-activated Temkin isotherm. Conversion of divalent to monovalent copper is also slow. In TEA and TSC alkaline copper solutions, the predominant species that undergo stepwise reduction contain only TEA ligands

  3. 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.

  4. The Alkaline Diet: Is There Evidence That an Alkaline ph Diet Benefits Health?

    International Nuclear Information System (INIS)

    This review looks at the role of an alkaline diet in health. Pub med 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

  5. Purification and Characterization of a Maltotetraose-Forming Alkaline (alpha)-Amylase from an Alkalophilic Bacillus Strain, GM8901

    OpenAIRE

    Kim, T U; Gu, B. G.; Jeong, J Y; Byun, S. M.; Shin, Y. C.

    1995-01-01

    An alkalophilic bacterium, Bacillus sp. strain GM8901, grown at pH 10.5 and 50(deg)C, produced five alkaline amylases in culture broth. At an early stage of the bacterial growth, amylase I (Amyl I) was produced initially and then, as cultivation progressed, four alkaline amylases, Amyl II, Amyl III, Amyl IV, and Amyl V, were produced from proteolytic degradation of Amyl I. A serine protease present in the culture medium was believed to be involved in Amyl I degradation. We purified Amyl I fro...

  6. Potentiometric assay for acid and alkaline phosphatase

    International Nuclear Information System (INIS)

    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

  7. 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...

  8. Enhanced production of alkaline protease by a mutant of Bacillus licheniformis N-2 for dehairing

    Directory of Open Access Journals (Sweden)

    Muhammad Nadeem

    2010-10-01

    Full Text Available The purpose of the present investigations was to improve the yield of alkaline protease for leather dehairing by subjecting the indigenous proteolytic strain Bacillus licheniformis N-2 to various mutagenic treatments viz. UV irradiations, NTG (N-methyl-N-nitro-N-nitrosoguinidine and MMS (methyl methane sulfonate. After screening on skim milk agar plates, a total of nine positive mutants were selected for shake flask experiments. Among these, the best proteolytic mutant designated as UV-9 showed 1.4 fold higher alkaline protease activity in preoptimized growth medium than the parent strain. The fermentation profile and kinetic parameters such u(h-1, Yp/s, Yp/x, Yx/s, q s, Qs, q p and Qp also indicated the superiority of the selected mutant UV-9 for alkaline protease production over the parent strain and rest of the mutants. The dehairing capability of mutant UV-9 alkaline protease was analyzed by soaking goat skin pieces for different time intervals (3-15 h at 40 º C. A complete dehairing without degradation of collagen was achieved after 12 h, indicating its commercial exploitation in leather industry.

  9. Organophilic clay suspension medium

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, G.G.; Parlman, R.M.; Stewart, W.

    1989-10-24

    This patent describes an improved liquid suspension medium for particulate solids. The suspension medium having been formed by admixing an organophilic clay wherein the clay is selected from the group consisting of bentonite, attapulgite, sepiolite and hectorite and admixtures thereof present in the quantity of about 0.5-8 weight percent with a liquid hydrocarbon present in the quantity of about 99-70 weight percent and at least one activator selected from the group consisting of phenyl hydroxyalkyl ethers.

  10. Concept medium programme

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program......The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program...

  11. 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....

  12. Alkaline magmatism in the eastern of Paraguay.Generals characteristics

    International Nuclear Information System (INIS)

    This paper deals with the distribution of alkaline occurrences in Paraguayan territory and their assemblage into different provinces. Also draws the attention to the petrographic and geochemical characteristics showed by the alkaline rock-types. (author)

  13. Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium using Nonionic Surfactants

    Czech Academy of Sciences Publication Activity Database

    Zukalová, Markéta; Rathouský, Jiří; Zukal, Arnošt

    2003-01-01

    Roč. 68, č. 10 (2003), s. 2019-2031. ISSN 0010-0765 Institutional research plan: CEZ:AV0Z4040901 Keywords : mesoporous SiO2 * sodium metasilicate * nonionic surfactants Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.041, year: 2003

  14. Preparation of nickel nanowire arrays electrode for urea electro-oxidation in alkaline medium

    Science.gov (United States)

    Guo, Fen; Ye, Ke; Cheng, Kui; Wang, Guiling; Cao, Dianxue

    2015-03-01

    Fully metallic nickel nanowire arrays (NWAs) electrode is prepared by electrodepositing nickel within the pores and over-plating on the surface of polycarbonate template (PCT) with subsequent dissolution of the template in dichloromethane. The as-prepared electrode is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Urea electro-oxidation reaction in KOH solution on the nickel NWAs electrode is investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) tests. The results show that the nickel NWAs electrode achieves an onset oxidation potential of 0.25 V (vs. Ag/AgCl) and a peak current density of 160 mA cm-2 in 5 mol L-1 KOH and 0.33 mol L-1 urea accompanied with considerable stability.

  15. Characterization of Pt-Pd/C Electrocatalyst for Methanol Oxidation in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    S. S. Mahapatra

    2011-01-01

    Full Text Available The Pt-Pd/C electrocatalyst was synthesized on graphite substrate by the electrochemical codeposition technique. The physicochemical characterization of the catalyst was done by SEM, XRD, and EDX. The electrochemical characterization of the Pt-Pd/C catalyst for methanol electro-oxidation was studied over a range of NaOH and methanol concentrations using cyclic voltammetry, quasisteady-state polarization, chronoamperometry, and electrochemical impedance spectroscopy. The activity of methanol oxidation increased with pH due to better OH species coverage on the electrode surface. At methanol concentration (>1.0 M, there is no change in the oxidation peak current density because of excess methanol at the electrode surface and/or depletion of OH− at the electrode surface. The Pt-Pd/C catalyst shows good stability and the low value of Tafel slope and charge transfer resistance. The enhanced electrocatalytic activity of the electrodes is ascribed to the synergistic effect of higher electrochemical surface area, preferred OH− adsorption, and ad-atom contribution on the alloyed surface.

  16. NMR investigation of aniline oligomers produced in the oxidation of aniline in alkaline medium

    Czech Academy of Sciences Publication Activity Database

    Kříž, Jaroslav; Konyushenko, Elena; Trchová, Miroslava; Stejskal, Jaroslav

    2011-01-01

    Roč. 60, č. 9 (2011), s. 1296-1302. ISSN 0959-8103 R&D Projects: GA ČR GA203/08/0686; GA AV ČR IAA400500905 Institutional research plan: CEZ:AV0Z40500505 Keywords : anilin e oligomers * polyaniline * anilin e oxidation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.902, year: 2011

  17. Guest-host interactions in the cleavage of phenylphenyl acetates by -cyclodextrin in alkaline medium

    Indian Academy of Sciences (India)

    V Raj; T Chandrakala; K Rajasekaran

    2008-05-01

    Kinetics of cleavage of phenylphenyl acetates (PPA) and several para-substituted PPAs in basic aqueous sodium carbonate-bicarbonate buffer containing -cyclodextrin (CD) have been studied. The reaction exhibits saturation type kinetics and CD accelerates the rate of cleavage by the formation of 1G : 1H inclusion complex. The kinetic results indicate that aryloxy moiety of PPA is included in the hydrophobic cavity of CD. The overall rate constants for the cleavage of the [CD-ester] complex correlate with the Hammett -constants and Hansch hydrophobicity parameters . At higher concentrations of CD, there is an additional catalysis due to the formation of weak 1G : 2H complex.

  18. Enhanced Production of Extracellular Alkaline Lipase by an Improved Strain of Pseudomonas aeruginosa MTCC 10,055

    Directory of Open Access Journals (Sweden)

    Deepali Bisht

    2012-01-01

    Full Text Available Problem statement: Lipases are industrially important enzymes having applications in numerous industries. For easy commercialization it is necessary to produce lipases at industrial level which could be achieved by strain improvement and medium formulation. Approach: In the present study strain improvement of Pseudomonas aeruginosa MTCC 10,055 was done by chemical mutagenesis using mutagen 4-nitroquinoline1-oxide for alkaline lipase production. Different fermentation parameters affecting lipase production were optimized using one-variable-at-a-time approach. Results: The selected mutant (M-05 exhibited 3.6-fold higher productivity over wild type. Maximum alkaline lipase was produced when culture was incubated at 35°C with initial medium pH 9.0 in 28 h with inoculum density 0.5% (v/v (Abs610-1.0. Supplementation of production medium with combination of castor oil and starch as carbon source and Triton-X-100 as surfactant significantly influenced the alkaline lipase production. The composition of fully optimized medium was determined to be (g L-1: (NH42SO4, 1.0; KH2PO4, 0.6; MgSO4, 0.4; yeast extract, 0.2; castor oil, 2.0; starch 20.0; gum arabic, 5.0; Triton-X-100, 1.0. An overall 14-fold enhanced production was achieved after complete medium optimization. Conclusion/Recommendations: The improved strain was capable to produce high titer of alkaline lipase at flask level, which can be examined at fermentor level to obtain sufficient enzyme yield to meet the world wide industrial demand.

  19. Polyhydroxyflavones as extractants. Communication 7. Solvent extraction of europrium complexes with morin from alkaline media

    International Nuclear Information System (INIS)

    This paper studies the analytical application of europium (III)-morin complex which is formed in alkaline medium and has an intense color. The extent of europium extraction was determined by adding to the extract a morin solution in isoamyl alcohol in a 50-100-fold excess with respect to europium. The dependence of the optical density of the extracts on the ph in the system europium (III)-morin-water-organic solvent for different excesses of the reagent is shown: this indicates formation of two extractable complexes, one being dominant in the pH range 4-7, the other at pH greater than or equal to 8.5. The extraction of the europium (III)-morin complex from alkaline solution is used for direct extraction-photometric determination of europium(III) in compounds of elements having amphoteric properties or forming amines (Zns, Mo03)

  20. PdNi hollow nanoparticles for improved electrocatalytic oxygen reduction in alkaline environments.

    Science.gov (United States)

    Wang, Meng; Zhang, Weimin; Wang, Jiazhao; Wexler, David; Poynton, Simon D; Slade, Robert C T; Liu, Huakun; Winther-Jensen, Bjorn; Kerr, Robert; Shi, Dongqi; Chen, Jun

    2013-12-11

    Palladium-nickel (PdNi) hollow nanoparticles were synthesized via a modified galvanic replacement method using Ni nanoparticles as sacrificial templates in an aqueous medium. X-ray diffraction and transmission electron microscopy show that the as-synthesized nanoparticles are alloyed nanostructures and have hollow interiors with an average particle size of 30 nm and shell thickness of 5 nm. Compared with the commercially available Pt/C or Pd/C catalysts, the synthesized PdNi/C has superior electrocatalytic performance towards the oxygen reduction reaction, which makes it a promising electrocatalyst for alkaline anion exchange membrane fuel cells and alkali-based air-batteries. The electrocatalyst is finally examined in a H2/O2 alkaline anion exchange membrane fuel cell; the results show that such electrocatalysts could work in a real fuel cell application as a more efficient catalyst than state-of-the-art commercially available Pt/C. PMID:24199836

  1. Anaerobic digestion of the microalga Spirulina at extreme alkaline conditions: biogas production, metagenome and metatranscriptome

    Directory of Open Access Journals (Sweden)

    Vimac Nolla-Ardevol

    2015-06-01

    Full Text Available A haloalkaline anaerobic microbial community obtained from soda lake sediments was used to inoculate anaerobic reactors for the production of methane rich biogas. The microalga Spirulina was successfully digested by the haloalkaline microbial consortium at alkaline conditions (pH 10, 2.0 M Na+. Continuous biogas production was observed and the obtained biogas was rich in methane, up to 96 %. Alkaline medium acted as a CO2 scrubber which resulted in low amounts of CO2 and no traces of H2S in the produced biogas. A hydraulic retention time of 15 days and 0.25 g Spirulina L-1 day-1 organic loading rate were identified as the optimal operational parameters. Metagenomics and metatranscriptomics analysis showed that the hydrolysis of the supplied substrate was mainly carried out by Bacteroidetes of the ML635J-40 aquatic group while the hydrogenotrophic pathway was the main producer of methane in a methanogenic community dominated by Methanocalculus.

  2. Specific Examples of Hybrid Alkaline Cement

    Directory of Open Access Journals (Sweden)

    Fernández-Jiménez Ana

    2014-04-01

    Full Text Available Hybrid alkaline cements are obtained by alkali-activating cementitious blends in the Na2O-CaO-SiO2-Al2O3-H2O system. The present paper discusses the results of activating different cementitious blends containing a low OPC clinker content ( 15MPa a 2 days different alkaline activators were used (liquid and solid. The reaction products obtained were also characterised by XRD, SEM/EDX and 27Al and 29Si NMRMAS. The results showed that the main reaction product was a mix of cementitious gels C-A-S-H and (N,C-A-S-H, and that their relative proportions were strongly influenced by the calcium content in the initial binder

  3. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    Alkaline electrolyzers have proven to operate reliable for decades on a large scale, but in order to become commercially attractive and compete against conventional technologies for hydrogen production, the production and investment costs have to be reduced. This may occur by increasing the...... operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... SrTiO3 was used for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen...

  4. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    radiation raises the necessity to store the produced energy. Hydrogen production by water electrolysis is one of the most promising ways to do so. Alkaline electrolyzers have proven to operate reliable for decades on a large scale (up to 160 MW), but in order to become commercially attractive and compete...... and oxygen with a new type of alkaline electrolysis cell at high temperatures and pressures. To perform measurements under high pressure and at elevated temperatures it was necessary to build a measurement system around an autoclave which could stand high temperatures up to 250 °C and pressures up to...... 200 bar as well as extremely caustic environments. Based on a literature study to identify resistant materials for these conditions, Inconel 600 was selected among the metals which are available for autoclave construction. An initial single atmosphere high temperature and pressure measurement setup...

  5. CARINA alkalinity data in the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    A. Velo

    2009-08-01

    Full Text Available Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Arctic, Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic.

    These data have gone through rigorous quality control (QC procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA data base were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; Arctic, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 98 were conducted in the Atlantic Ocean and of these, 75 cruises report alkalinity values.

    Here we present details of the secondary QC on alkalinity for the Atlantic Ocean part of CARINA. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the alkalinity values for 16 of the cruises in the Atlantic Ocean region. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s. Based on our analysis we estimate the internal accuracy of the CARINA-ATL alkalinity data to be 3.3 μmol kg−1. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.

  6. Alkaline leaching of iron and steelmaking dust

    OpenAIRE

    Stafanova, Anna; Aromaa, Jari

    2012-01-01

    Steel production generates significant quantities of dust and sludge in blast furnaces (BF),basic oxygen furnaces (BOF), and electric arc furnaces (EAF). These dusts contain toxicelements, such as heavy metals, and are thus classified as harmful waste making the disposalof them expensive. In addition, direct recycling of dust back to steel production is hindered dueto the presence of zinc. In this literature survey the alkaline leaching of zinc from iron and steelmaking dusts isreviewed. T...

  7. Bifunctional Catalysts for Alkaline Fuel Cells

    Czech Academy of Sciences Publication Activity Database

    Klápště, Břetislav; Vondrák, Jiří; Velická, Jana

    Vol. 1. Brno : Akademické nakladatelství CERM, 2000 - (Vondrák, J.; Sedlaříková, M.), s. 24.1-24.4 ISBN 80-214-1614-9. [Advanced Batteries and Accumulators /1./. Brno (CZ), 28.08.2000-01.09.2000] R&D Projects: GA MŠk ME 216 Institutional research plan: CEZ:AV0Z4032918; CEZ:MSM 262200010 Keywords : alkaline * catalysts * electrochemistry Subject RIV: CG - Electrochemistry

  8. The Interstellar Medium

    CERN Document Server

    Lequeux, James

    2005-01-01

    Describing interstellar matter in our galaxy in all of its various forms, this book also considers the physical and chemical processes that are occurring within this matter. The first seven chapters present the various components making up the interstellar matter and detail the ways that we are able to study them. The following seven chapters are devoted to the physical, chemical and dynamical processes that control the behaviour of interstellar matter. These include the instabilities and cloud collapse processes that lead to the formation of stars. The last chapter summarizes the transformations that can occur between the different phases of the interstellar medium. Emphasizing methods over results, "The Interstellar Medium" is written for graduate students, for young astronomers, and also for any researchers who have developed an interest in the interstellar medium.

  9. Heavy water production by alkaline water electrolysis

    International Nuclear Information System (INIS)

    Several heavy water isotope production processes are reported in literature. Water electrolysis in combination with catalytic exchange CECE process is considered as a futuristic process to increase the throughput and reduce the cryogenic distillation load but the application is limited due to the high cost of electricity. Any improvement in the efficiency of electrolyzers would make this process more attractive. The efficiency of alkaline water electrolysis is governed by various phenomena such as activation polarization, ohmic polarization and concentration polarization in the cell. A systematic study on the effect of these factors can lead to methods for improving the efficiency of the electrolyzer. A bipolar and compact type arrangement of the alkaline water electrolyzer leads to increased efficiency and reduced inventory in comparison to uni-polar tank type electrolyzers. The bipolar type arrangement is formed when a number of single cells are stacked together. Although a few experimental studies have been reported in the open literature, CFD simulation of a bipolar compact alkaline water electrolyzer with porous electrodes is not readily available.The principal aim of this study is to simulate the characteristics of a single cell compact electrolyzer unit. The simulation can be used to predict the Voltage-Current Density (V-I) characteristics, which is a measure of the efficiency of the process.The model equations were solved using COMSOL multi-physics software. The simulated V-I characteristic is compared with the experimental data

  10. The fate of added alkalinity in model scenarios of ocean alkalinization

    Science.gov (United States)

    Ferrer González, Miriam; Ilyina, Tatiana

    2014-05-01

    The deliberate large-scale manipulation of the Earth's climate (geo-engineering) has been proposed to mitigate climate change and ocean acidification. Whilst the mitigation potential of these technologies could sound promising, they may also pose many environmental risks. Our research aims at exploring the ocean-based carbon dioxide removal method of alkalinity enhancement. Its mitigation potential to reduce atmospheric CO2 and counteract the consequences of ocean acidification, risks and unintended consequences are studied. In order to tackle these questions, different scenarios are implemented in the state-of-the-art Earth system model of the Max Planck Institute for Meteorology. The model configuration is based on the 5th phase of the coupled model intercomparison project following a high CO2 future climate change scenario RCP8.5 (in which radiative forcing rises to 8.5 W/m² in 2100). Two different scenarios are performed where the alkalinity is artificially added globally uniformly in the upper ocean. In the first scenario, alkalinity is increased as a pulse by doubling natural values of the first 12 meters. In the second scenario we add alkalinity into the same ocean layer such that the atmospheric CO2 concentration is reduced from RCP8.5 to RCP4.5 levels (with the radiative forcing of 4.5 W/m² in 2100). We investigate the fate of the added alkalinity in these two scenarios and compare the differences in alkalinity budgets. In order to increase oceanic CO2 uptake from the atmosphere, enhanced alkalinity has to stay in the upper ocean. Once the alkalinity is added, it will become part of the biogeochemical cycles and it will be distributed with the ocean currents. Therefore, we are particularly interested in the residence time of the added alkalinity at the surface. Variations in CO2 partial pressure, seawater pH and saturation state of carbonate minerals produced in the implemented scenarios will be presented. Collateral changes in ocean biogeochemistry and

  11. Efficient Distributed Medium Access

    CERN Document Server

    Shah, Devavrat; Tetali, Prasad

    2011-01-01

    Consider a wireless network of n nodes represented by a graph G=(V, E) where an edge (i,j) models the fact that transmissions of i and j interfere with each other, i.e. simultaneous transmissions of i and j become unsuccessful. Hence it is required that at each time instance a set of non-interfering nodes (corresponding to an independent set in G) access the wireless medium. To utilize wireless resources efficiently, it is required to arbitrate the access of medium among interfering nodes properly. Moreover, to be of practical use, such a mechanism is required to be totally distributed as well as simple. As the main result of this paper, we provide such a medium access algorithm. It is randomized, totally distributed and simple: each node attempts to access medium at each time with probability that is a function of its local information. We establish efficiency of the algorithm by showing that the corresponding network Markov chain is positive recurrent as long as the demand imposed on the network can be supp...

  12. Radon in geological medium

    International Nuclear Information System (INIS)

    The paper presented deals with behavior of the radon in geological medium and with some results of the radon survey in Bratislava and Kosice regions. 1) The av has been detected in the holes 0.80 m deep. The density of observations - 3 reference areas (one represents 20 stations) per 1 km2. The radon risk maps in 1:25000 and 1:50000 scales have been compiled. The 56.8% of the project area lies in low radon risk, 37.6% in medium radon risk and 5.6% in high radon risk. Follow-up monitoring of the equivalent volume radon activity (EVRA) at the flats, located in the areas with high radon risk of the surface layer, has showed values several times higher than Slovak limits (Marianka, Raca, Vajnory). The evidence that neotectonic is excellent medium for rising up emanation to the subsurface layer, is shown on the map. The tectonic zone of Liscie udolie in Bratislava-Karlova Ves area has been clearly detected by profile radon survey (av > 50 kBq/m3). 2) At present, northern half of the area of Kosice in question was covered by radon survey. The low and medium radon risks have been observed here, while localities with high radon risk are small in extent. The part of radon risk and soil permeability map from northern Kosice area is shown. (J.K.) 3 figs., 2 refs

  13. Mechanistic investigation on the oxidation of kinetin by Ag(III) periodate complex in aqueous alkaline media: A kinetic approach

    Indian Academy of Sciences (India)

    S D Lamani; A M Tatagar; S T Nandibewoor

    2010-11-01

    The oxidation of amino acid, kinetin (KNT) by diperiodatoargentate(III) (DPA) in alkaline medium at a constant ionic strength of 0.5 mol dm-3 was studied spectrophtometrically. The reaction between KNT and DPA in alkaline medium exhibits 1 : 3 stoichiometry (KNT : DPA). Intervention of free radicals was observed in the reaction. Based on the observed orders and experimental evidences, a mechanism involving the monoperiodatoargentate(III) (MPA) as the reactive oxidant species has been proposed. The products, furon-2-methanol and para-nitro-purine were identified by spot test and characterized by spectral studies. The rate constants and associated activation parameters for the proposed mechanism as well as the thermodynamic quantities for different equilibrium steps are reported and discussed.

  14. Hf-Nd isotopic and trace element constraints on the genesis of alkaline and calc-alkaline lamprophyres

    International Nuclear Information System (INIS)

    Major and trace element, Nd and for the first time Hf isotopic compositions of Central European Hercynian and Alpine alkaline (nephelinites) and calc-alkaline (minettes) lamprophyres are reported. The alkaline dikes have significantly higher initial εNd values (+3.9 to +5.2) than the calc-alkaline dikes (-1 to -7). Their initial εHf values range between +1.9 and +6.0. Both groups show the typical high level of incompatible-element enrichment. In addition the calc-alkaline lamprophyres are characterized by an overabundance of Cs relative to Rb, high Ba/La and Ba/Sr ratios as well as depletion in Nb, Ti and Ta. Covariations between initial εHf-εNd and trace elements suggest that crust-mantle mixing processes were involved in the formation of the calc-alkaline mafic magmas. These data give way to a general, refined model of lamprophyre genesis and provide information about enrichment processes in the subcontinental lithospheric mantle. It is suggested that alkaline and calc-alkaline lamprophyres originate from similar mantle segments. Alkaline lamprophyres can be generated by 10% partial melting of a metasomatically enriched garnet peridotite. Calc-alkaline lamprophyres, however, can be generated in subduction related environments by mixing of 5-15% sedimentary melts, strongly enriched in K, Rb, Zr, Hf, Y and REE, produced by partial melting of subducted oceanic sediments, with a metasomatically enriched mantle source similar to that suggested for the ultramafic alkaline dikes. (orig.)

  15. How Should an Increase in Alkaline Phosphatase Activity Be Interpreted?

    International Nuclear Information System (INIS)

    Low-level laser therapy, commonly known as LLLT, is the application of low power, monochromatic, and coherent light to injuries and lesions to stimulate healing and give pain relief. There are conflicting reports in the literature regarding the role of ALP. Objective: this study aimed to compare the cellular responses of wounded human skin fibroblasts exposed to doses of 0.5 J/cm2, 2.5 J/cm2, 5 J/cm2, or 16 J/cm2 using LLLT with a Helium-Neon laser (632.8 nm, 18.8 mW power output, 2.07 mW/cm2 power density, and 3.4 cm diameter spot size or area 9.1?cm2) to elucidate the role of alkaline phosphatase (ALP) in cell proliferation. Methods: cellular responses to laser irradiation were evaluated using ALP enzyme activity, LDH membrane integrity, neutral red for cell proliferation, optical density at 540?nm, and basic fibroblast growth factor (bFGF) expression. Results: results suggest that an increase in ALP is negatively correlated with cell growth depending on the concentration of growth factors in the medium. Results also indicate that an increase in ALP may be related to cellular damage. Conclusion: since the exact role of ALP is unknown, the ALP enzyme activity assay should be considered in conjunction with other cell proliferation assays such as neutral red, optical density, or more specifically bFGF expression.

  16. Removal of uranium, plutonium and americum particles from alkaline colloidal solution by froth flotation

    International Nuclear Information System (INIS)

    Fine particulate oxides of actinide elements can be separated from other oxidized material - in particular, Mg(OH)2 -by froth flotation in slightly alkaline media. The flotation medium contains sodium bicarbonate and the frother, a cationic surfactant such as cetyl trimethyl ammonium bromide. A series of small batch flotation tests used to characterize the process is described. In a typical good run, 99% of the uranium can be removed in 30% of the initial water. About 25% of the Mg(OH)2 is recovered in the same type of experiment. (author)

  17. Studies of corrosion behaviour in alkaline environment of binary Mg-Li alloys for plastic forming

    OpenAIRE

    M. Żmudzińska; A. Białobrzeski; K. Saja

    2011-01-01

    The article discusses studies and corrosion tests of binary Mg-Li alloys for plastic forming examined in an alkaline medium (5% NaClsolution) for the time of 0-144 hours. In short it can be stated that the increase of Li content in magnesium alloys from 3% to 9% increasesthe corrosion resistance of alloy (the lowest susceptibility to corrosion in NaCl solution showed Mg- Li9 alloy). Increasing the content ofLi in alloy to over 9% resulted in a significant increase of the susceptibility to cor...

  18. Studies of corrosion behaviour in alkaline environment of binary Mg-Li alloys for plastic forming

    Directory of Open Access Journals (Sweden)

    M. Żmudzińska

    2011-07-01

    Full Text Available The article discusses studies and corrosion tests of binary Mg-Li alloys for plastic forming examined in an alkaline medium (5% NaClsolution for the time of 0-144 hours. In short it can be stated that the increase of Li content in magnesium alloys from 3% to 9% increasesthe corrosion resistance of alloy (the lowest susceptibility to corrosion in NaCl solution showed Mg- Li9 alloy. Increasing the content ofLi in alloy to over 9% resulted in a significant increase of the susceptibility to corrosion.

  19. The Detection of Alkaline Phosphatase Using an Electrochemical Biosensor in a Single-Step Approach

    OpenAIRE

    Chung-Chiun Liu; Kevin Wang; Wang, Joanne H.; Brandon Bartling

    2009-01-01

    A one-step, single use, disposable Alkaline Phosphatase (ALP) biosensor has been developed. It is based on the detection of phenol produced by an ALP enzymatic reaction. It can operate at 25 °C in a pH 10 medium. It measures ALP of 0–300 IU/L. The permissible concentrations of glucose, ascorbic acid and urea without interference are 10 mM/L, 5 mg/L and 400 mg/L, respectively. Experimental results are compared to those obtained by spectrophotometric measurements in bovine serum. Excellent line...

  20. Solid alkaline membrane fuel cell : what are they advantages and drawbacks compared to proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Coutanceau, C.; Baranton, S.; Simoes, M. [Univ. de Poitiers, Poitiers (France). Laboratoire de Catalyse en Chimie Organique, UMR CNRS

    2010-07-01

    Low temperature fuel cells such as proton exchange membrane fuel cells (PEMFCs) and direct alcohol fuel cells (DAFCs) are promising power sources for portable electronics and transportation applications. However, these fuel cells require high amounts of platinum at the anodes to achieve high cell performance. Although alkaline membrane fuel cells (AFCs) may be an alternative to PEMFCs, the technology of low temperature fuel cells is less developed than that of fuel cells working with a solid acid electrolyte. Interest in solid alkaline membrane fuel cells (SAMFCs) has increased in recent years because it is easier to activate the oxidation and reduction reactions in alkaline medium than in acidic medium. Fewer platinum based catalysts are needed due to higher electrode kinetics. The development of hydroxyl conductive membrane makes this technology available, but the fuel to be used in the system must be considered. Pure hydrogen or hydrogen-rich gases offer high electric efficiency, but their production, storage, and distribution are not sufficient for a large-scale development. This paper discussed the relatively good electroreactivity of polyols such as glycerol and ethylene glycol in a SAMFC, as well as sodium borohydride (NaBH{sub 4}) as an alternative. The working principle of SAMFCs was also presented along with considerations regarding the electrochemical reactions occurring at the electrodes, and requirements concerning the catalysts, the triple phase boundary in the electrode and the anionic membrane. Palladium based catalysts were found to be an interesting alternative to platinum in SAMFCs. In situ FTIR measurements and oxidation products analysis was used to determine the electrooxidation pathways of alcohol and NaBH{sub 4}in alkaline medium. The study also included a comparison with oxidation mechanisms in acid medium. 8 refs.

  1. PRODUCTION AND PARTIAL CHARACTERIZATION OF ALKALINE PROTEASE FROM BACILLUS TEQUILENSIS STRAINS CSGAB0139 ISOLATED FROM SPOILT COTTAGE CHEESE

    OpenAIRE

    Aruna.K; Jill Shah; Radhika Birmole

    2014-01-01

    An alkaline protease producing strain was isolated from spoilt cottage cheese sample which was identified as Bacillus tequilensis strain SCSGAB0139 on the basis of morphological, cultural, biochemical characteristics and 16S rRNA sequence analysis. Primary screening for protease production was carried out by observing for zone of hydrolysis on skim milk agar, GYEA milk agar and gelatin agar plates. Physicochemical parameters like pH of the medium, incubation time and temperature, aeration and...

  2. 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...

  3. 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.

  4. The Local Interstellar Medium

    CERN Document Server

    Redfield, S

    2006-01-01

    The Local Interstellar Medium (LISM) is a unique environment that presents an opportunity to study general interstellar phenomena in great detail and in three dimensions. In particular, high resolution optical and ultraviolet spectroscopy have proven to be powerful tools for addressing fundamental questions concerning the physical conditions and three-dimensional (3D) morphology of this local material. After reviewing our current understanding of the structure of gas in the solar neighborhood, I will discuss the influence that the LISM can have on stellar and planetary systems, including LISM dust deposition onto planetary atmospheres and the modulation of galactic cosmic rays through the astrosphere - the balancing interface between the outward pressure of the magnetized stellar wind and the inward pressure of the surrounding interstellar medium. On Earth, galactic cosmic rays may play a role as contributors to ozone layer chemistry, planetary electrical discharge frequency, biological mutation rates, and cl...

  5. Medium of Blood

    Directory of Open Access Journals (Sweden)

    Eddie Glenn

    2012-06-01

    Full Text Available Blood quantum, the measurement of American Indian ancestry possessed by members of America’s Indigenous nations, is most often considered a rubric utilized by the federal government in an oppressive form, or by tribal nations themselves as standards of tribal citizenship requirements. In this essay, the authors recontextualize blood as a medium of national identity within the context of the Cherokee Nation of Oklahoma. Such decentering, as presented here, illuminates Cherokee nationhood in ways that have significant political import.

  6. The Local Interstellar Medium

    OpenAIRE

    Ferlet, R.

    2006-01-01

    The Local Interstellar Medium (LISM) is a unique environment that presents an opportunity to study general interstellar phenomena in great detail and in three dimensions. In particular, high resolution optical and ultraviolet spectroscopy have proven to be powerful tools for addressing fundamental questions concerning the physical conditions and three-dimensional (3D) morphology of this local material. After reviewing our current understanding of the structure of gas in the solar neighborhood...

  7. Concept medium program

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    The present essays is an attempt to dertermine the architecural project of the 21st century in realation to a modern conception of space as the medium of architecture, and of society as its program. This attempt adopts the internal point of view of an architect in describing a modern architectural...... project within the framework: concept - program, these notions being concieved as spatial representations primarily and immediately "given" to architecture....

  8. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    International Nuclear Information System (INIS)

    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

  9. 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.

  10. Inhibition of Alkaline Flocculation by Algal Organic Matter for Chlorella vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Vandamme, Dries; Beuckels, Annelies; Vadelius, Eric; Depraetere, Orily; Noppe, Wim; Dutta, Abhishek; Foubert, Imogen; Laurens, Lieve; Muylaert, Koenraad

    2016-01-01

    Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. An addition of 30–50 mg L-1 alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. Furthermore, these results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time.

  11. 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.

  12. Dissolution kinetics of smectite under alkaline conditions

    International Nuclear Information System (INIS)

    Extensive use of cement for encapsulation, backfilling, and grouting purposes is envisaged in radioactive waste disposal. Degradation of cement materials through contact with groundwater can produce a high pH pore fluid initially ranging from pH 13.0 to 13.5. The pore fluid pH eventually decreases to moderately alkaline ranges due to formation and evolution of subsequent materials. The high pH pore fluids can migrate outwards where it will chemically react with the host rock, and the bentonite utilized to enhance the repository's integrity. These chemical reactions degrade the host rocks' and bentonite ability to absorb radionuclides. Smectites comprising the bulk of bentonite can lose some of their desirable properties during the early stages of bentonite-cement-pore fluid interaction. This has been a key research issue in the performance assessment of radioactive waste disposal system. Elucidating the effects of high pH pore fluid on the physical and chemical properties of smectites (i.e. especially dissolution behavior and rates) is of utmost importance. Stirred-flow-through dissolution experiments were utilized to derive reliable dissolution rates for smectites under neutral to highly alkaline conditions. The effects of pH and temperature on smectite dissolution rates were also investigated. (author)

  13. Biological alkalinity generation in acid mine drainage

    International Nuclear Information System (INIS)

    Ecological Engineering and Biological Polishing technologies are a decommissioning approach to inactive coal, uranium and base metal mining operations. To improve acid mine drainage water, some fundamental aspects of wetland ecology and sediment microbiology are combined. The combination provides conditions which allow biomineralization of the contaminants. The authors report here the first records of microbial alkalinity generation in acid mine drainage, through the utilization of the ARUM (Acid Reduction Using Microbiology) process. Increases in pH are brought about by alkalinity-generating microbes such as sulfate reducers, iron reducers, methanogens, or denitrifiers. The ARUM process has been successful in increasing pH from 2.5 to 7.0 in laboratory-scale flow-through reactors operated continuously for more than 120 days. Ni was also reduced from 13 mg/l to < 0.01 mg/l. Batch ARUMators in the field have also performed well. Design parameters are being developed for low flow rates of 5 l/min in a pilot-scale system receiving seepage from mine tailings

  14. The effect of alkaline agents on retention of EOR chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, P.B.

    1991-07-01

    This report summarizes a literature survey on how alkaline agents reduce losses of surfactants and polymers in oil recovery by chemical injection. Data are reviewed for crude sulfonates, clean anionic surfactants, nonionic surfactants, and anionic and nonionic polymers. The role of mineral chemistry is briefly described. Specific effects of various alkaline anions are discussed. Investigations needed to improve the design of alkaline-surfactant-polymer floods are suggested. 62 refs., 28 figs., 6 tabs.

  15. Guest-host interactions in the alkaline bleaching of triphenylmethane dyes catalysed by -cyclodextrin

    Indian Academy of Sciences (India)

    V Raj; A Sarathi; T Chandrakala; S Dhanalakshmi; R Sudha; K Rajasekaran

    2009-07-01

    The rates of alkaline bleaching of triphenylmethane dyes crystal violet (CV), malachite green (MG) and rosaniline (RA) have been measured spectrophotometrically in an aqueous medium at 30°C in the presence of -cyclodextrin (CD). At lower concentrations of CD, CV forms productive 1 : 1 (G : H) complex. At higher concentrations of CD, it forms unproductive 1 : 2 (G : H) complex. For the bleaching of MG, CD accelerates or decelerates the rate depending on pH of the medium by forming 1 : 1 (G : H) inclusion complex. Analysis of rate data shows that MG undergoes fading by mixed order process. CD decelerates the water reaction and accelerates hydroxide ion reaction. In the case of RA, both water reaction as well as hydroxide ion reaction are retarded by CD by the formation of inclusion complex.

  16. Nuclear medium effects in $\

    CERN Document Server

    Haider, H; Athar, M Sajjad; Vacas, M J Vicente

    2011-01-01

    We study the nuclear medium effects in the weak structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ in the deep inelastic neutrino/antineutrino reactions in nuclei. We use a theoretical model for the nuclear spectral functions which incorporates the conventional nuclear effects, such as Fermi motion, binding and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. The calculations have been performed using relativistic nuclear spectral functions which include nucleon correlations. Our results are compared with the experimental data of NuTeV and CDHSW.

  17. A newly high alkaline lipase: an ideal choice for application in detergent formulations

    Directory of Open Access Journals (Sweden)

    Cherif Slim

    2011-11-01

    Full Text Available Abstract Background Bacterial lipases received much attention for their substrate specificity and their ability to function in extreme environments (pH, temperature.... Many staphylococci produced lipases which were released into the culture medium. Reports of thermostable lipases from Staphylococcus sp. and active in alkaline conditions are not previously described. Results A newly soil-isolated Staphylococcus sp. strain ESW secretes an induced lipase in the culture medium. The effects of temperature, pH and various components in a detergent on the activity and stability of Staphylococcus sp. lipase (SL1 were studied in a preliminary evaluation for use in detergent formulation solutions. The enzyme was highly active over a wide range of pH from 9.0 to 13.0, with an optimum at pH 12.0. The relative activity at pH 13.0 was about 60% of that obtained at pH 12.0. It exhibited maximal activity at 60°C. This novel lipase, showed extreme stability towards non-ionic and anionic surfactants after pre-incubation for 1 h at 40°C, and relative stability towards oxidizing agents. Additionally, the crude enzyme showed excellent stability and compatibility with various commercial solid and liquid detergents. Conclusions These properties added to the high activity in high alkaline pH make this novel lipase an ideal choice for application in detergent formulations.

  18. Dolomite Dissolution in Alkaline Cementious Media

    Science.gov (United States)

    Mittermayr, Florian; Klammer, Dietmar; Köhler, Stephan; Dietzel, Martin

    2010-05-01

    Chemical alteration of concrete has gained much attention over the past years as many cases of deterioration due to sulphate attack, thaumasite formation (TSA) or alkali silica reactions (ASR) have been reported in various constructions (Schmidt et al, 2009). Much less is known about the so called alkali carbonate reaction (ACR). It is believed that dolomite aggregates can react with the alkalis from the cement, dissolve and form calcite and brucite (Katayama, 2004). Due to very low solubility of dolomite in alkaline solutions this reaction seems doubtful. In this study we are trying to gain new insides about the conditions that can lead to the dissolution of dolomite in concrete. Therefore we investigated concrete samples from Austrian tunnels that show partially dissolved dolomite aggregates. Petrological analysis such as microprobe, SEM and Raman spectroscopy as well as a hydrochemical analysis of interstitial solutions and ground water and modelling with PhreeqC (Parkhurst and Appelo, 1999) are carried out. In addition a series of batch experiments is set up. Modelling approaches by PhreeqC show a thermodynamically possibility in the alkaline range when additional Ca2+ in solution causes dolomite to become more and more undersaturated as calcite gets supersaturated. Interacting ground water is enriched in Ca2+and saturated with respect to gypsum as marine evaporites are found in situ rocks. Furthermore it is more likely that Portlandite (Ca(OH)2) plays a more important role than Na and K in the cement. Portlandite acts as an additional Ca2+ source and is much more abundant than the alkalies. Some interstitial solutions are dominated mainly by Na+ and SO42- and reach concentrations up to 30 g/l TDS. It is believed that solutions can even reach thenardite saturation as efflorescences are found on the tunnel walls. In consequence dolomite solubility increases with increasing ionic strength. pH > 11 further accelerate the process of dedolomitization by the removal

  19. Binary and ternary palladium based electrocatalysts for alkaline direct glycerol fuel cell

    Science.gov (United States)

    Geraldes, Adriana Napoleão; da Silva, Dionisio Furtunato; e Silva, Leonardo Gondim de Andrade; Spinacé, Estevam Vitório; Neto, Almir Oliveira; dos Santos, Mauro Coelho

    2015-10-01

    Pd/C, PdAu/C 50:50, PdSn/C 50:50, PdAuSn/C 50:40:10 and PdAuSn/C 50:10:40 electrocatalysts are prepared using an electron beam irradiation reduction method and tested for glycerol electro-oxidation in alkaline medium. X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Transmission electron Microscopy (TEM) and Cyclic Voltammetry (CV) are used to characterize the resulting materials. The activity for glycerol electro-oxidation is tested in alkaline medium at room temperature using Cyclic Voltammetry and Chronoamperometry (CA) and in a single alkaline direct glycerol fuel cell (ADGFC) at temperature range of 60-90 °C. EDX analysis demonstrate that Pd:Au:Sn atomic ratios are very similar to the nominal ones. X-ray diffractograms of PdAuSn/C electrocatalysts evidence the presence of Pd (fcc), Au (fcc) and SnO2 phases. TEM analysis demonstrates a good dispersion of the nanoparticles on the carbon support with some agglomerates. Cyclic Voltammetry experiments suggest that PdAuSn/C electrocatalysts demonstrate better results. In single fuel cell tests, at 85 °C, using 2.0 mol L-1 glycerol in 2.0 mol L-1 KOH solutions, the electrocatalyst PdAuSn/C 50:40:10 demonstrate highest power density (51 mW cm-2) and the 120 h durability tests demonstrate a 210 μV h-1 degradation rate.

  20. Hot interstellar medium

    International Nuclear Information System (INIS)

    In view of that the diffuse component of soft X-rays is emitted mainly by extended supernova remnants and the hot interstellar medium produced thereby, the following three points are discussed. (1.) In the early stage of supernova remnants expanding in low density media, neither the equipartition of energy between electrons and ions nor the ionization equilibrium holds. The shock structure is modified by the pressure of hot plasma. X-ray features of the North Polar Spur are interpreted by taking these points into account. (2.) Several compilations of X-ray line emission are compared. Those by Kato and by Raymond and Smith are different in the equilibrium ion abundances and the collisional excitation rates for some important lines. The origins of differences are shown for some examples. It is demonstrated how the difference affects astrophysical interpretations. (3.) The solar system is surrounded by a hot, tenuous interstellar medium extended in the direction of 1 -- 1500 in the northern hemisphere. In other directions X-rays emitted farther than absorbing clouds are appreciable. (author)

  1. The Local Interstellar Medium

    Science.gov (United States)

    Redfield, S.

    2006-09-01

    The Local Interstellar Medium (LISM) is a unique environment that presents an opportunity to study general interstellar phenomena in great detail and in three dimensions. In particular, high resolution optical and ultraviolet spectroscopy have proven to be powerful tools for addressing fundamental questions concerning the physical conditions and three-dimensional (3D) morphology of this local material. After reviewing our current understanding of the structure of gas in the solar neighborhood, I will discuss the influence that the LISM can have on stellar and planetary systems, including LISM dust deposition onto planetary atmospheres and the modulation of galactic cosmic rays through the astrosphere --- the balancing interface between the outward pressure of the magnetized stellar wind and the inward pressure of the surrounding interstellar medium. On Earth, galactic cosmic rays may play a role as contributors to ozone layer chemistry, planetary electrical discharge frequency, biological mutation rates, and climate. Since the LISM shares the same volume as practically all known extrasolar planets, the prototypical debris disks systems, and nearby low-mass star-formation sites, it will be important to understand the structures of the LISM and how they may influence planetary atmospheres.

  2. DENSE MEDIUM CYCLONE OPTIMIZATON

    Energy Technology Data Exchange (ETDEWEB)

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  3. Alkaline pulping of some eucalypts from Sudan.

    Science.gov (United States)

    Khristova, P; Kordsachia, O; Patt, R; Dafaalla, S

    2006-03-01

    Four eucalypts (Eucalyptus camaldulensis, Eucalyptus microtheca, Eucalyptus tereticornis and Eucalyptus citriodora) grown in Sudan were examined for their suitability for pulping and papermaking with different alkaline methods. Their physical, morphological and chemical characteristics are reported. The pulping trials with E. citriodora and E. tereticornis were carried out using the kraft-AQ, soda-AQ, modified AS/AQ (ASA), ASAM and kraft methods. For the other two species, only the ASAM and the kraft process were applied. ASAM pulping gave the best results in terms of yield, degree of delignification, mechanical and optical pulp properties. The best pulps, obtained in kraft and ASAM cooking of E. citriodora, were bleached to 88% ISO brightness in a totally chlorine free bleaching sequence (OQ1O/PQ2P). The bleached pulps, especially the ASAM pulp, showed good papermaking properties and would be suitable for manufacture of writing and printing grades of paper. PMID:15935655

  4. Corrosion of copper in alkaline chloride environments

    International Nuclear Information System (INIS)

    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 Cu2O/Cu(OH)2 film. The corrosion potential will be determined by the equilibrium potential for the Cu2O/Cu(OH)2 couple under oxic conditions, or by the Cu/Cu2O 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 O2 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 CuCl2 - and of the reduction of O2. The development of anoxic conditions and an increase in pore-water sulphide concentration will result in

  5. Hydrogen in aluminum during alkaline corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, Saikat; Ai, Jiahe [Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Hebert, Kurt R., E-mail: krhebert@iastate.ed [Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Ho, K.M.; Wang, C.Z. [US DOE, Ames Laboratory, Ames, IA 50011 (United States)] [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)

    2010-07-30

    The thermodynamic state of hydrogen in aluminum during alkaline corrosion was investigated, using a two-compartment hydrogen permeation cell with an Al/Pd bilayer membrane. The open-circuit potential of the Pd layer in a pH 7.0 buffer solution was monitored to sense the hydrogen chemical potential, {mu}{sub H}. At pH 12.5-13.5, the measurements established a minimum {mu}{sub H} of 0.55 eV relative to the ideal gas reference, equivalent to a H{sub 2} gas pressure of 5.7 GPa. Statistical mechanics calculations show that vacancy-hydrogen defects are stable in Al at this condition. A dissolution mechanism was proposed in which H at very high {mu}{sub H} is produced by oxidation of interfacial aluminum hydride. The mechanism explains the observed rapid accumulation of H in the metal by extensive formation of vacancy-hydrogen defects.

  6. Alkaline lixiviation of uranium in granitic pegmatite

    International Nuclear Information System (INIS)

    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 Na2CO3/NaHCO3 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 700C for a 24 hour time period. (author)

  7. Polyvinyl alcohol membranes as alkaline battery separators

    Science.gov (United States)

    Sheibley, D. W.; Gonzalez-Sanabria, O.; Manzo, M. A.

    1982-01-01

    Polyvinly alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the separator and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of separator screening tests and cell tests for several variations of PBA films are discussed.

  8. Retention of alkaline earth elements in man

    International Nuclear Information System (INIS)

    The data on human metabolism and long-term retention of alkaline earth elements (133Ba injected into six healthy male volunteers at age 25-81 y and 45Ca and 85Sr received by one healthy male volunteer) are presented. Excreta were collected for 2-3 weeks after injection of the tracer into an antecubital vein. Activity in urine, ashed faeces and early samples of blood plasma was determined by gamma-ray scintillation spectrometry. Whole body retention has been assessed through serial measurements of body radioactivity. The injected 133Ba apparently became mainly skeletal within several days, much earlier than predicted by the ICRP model. The whole-body retention at 32 d ranged from 5 to 14%, the rate of loss correlating with the excretory plasma clearance rate. No age-related trends were identified in the metabolism of Ca and Sr. 2 refs, 2 figs

  9. 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  |

  10. Production of alkaline protease from Cellulosimicrobium cellulans

    OpenAIRE

    Luciana Ferracini-Santos; Sato, Hélia H

    2009-01-01

    Cellulosimicrobium cellulans is one of the microorganisms that produces a wide variety of yeast cell wall-degrading enzymes, β-1,3-glucanase, protease and chitinase. Dried cells of Saccharomyces cerevisiae were used as carbon and nitrogen source for cell growth and protease production. The medium components KH2PO4, KOH and dried yeast cells showed a significant effect (p

  11. Facilitated transport of alkaline and alkaline earth metals through liquid membranes with acidic extractants

    International Nuclear Information System (INIS)

    The removal of radioactive Cs and Sr from the liquid waste of nuclear plants is an important problem for both the defense arid the energy industries. Experiments with bulk liquid membranes and liquid membranes, immobilized on porous support, demonstrated the applicability of these systems for active transport of alkaline cations and Sr from alkaline to acidic solution against the concentration gradient of the metal. The mechanism of transport facilitated by fatty acids for alkali metals, or by di-2-ethylhexyl phosphoric acid for Sr in the presence of Ca and EDTA, corresponds to the open-quotes big carrouselclose quotes model, according to which the carrier is distributed between the membrane and aqueous solutions, where metal/H+- ion exchange takes place. The rate limiting step is the reextraction of Sr from the membrane into the acceptor (acidic) solution and is determined by the diffusion of the protonated carrier from the stripping acidic solution through the corresponding unstirred layer

  12. Nucleotide and amino acid sequences of human intestinal alkaline phosphatase: close homology to placental alkaline phosphatase

    International Nuclear Information System (INIS)

    A cDNA clone for human adult intestinal alkaline phosphatase (ALP) [orthophosphoric-monoester phosphohydrolase (alkaline optimum); EC 3.1.3.1] was isolated from a λgt11 expression library. The cDNA insert of this clone is 2513 base pairs in length and contains an open reading frame that encodes a 528-amino acid polypeptide. This deduced polypeptide contains the first 40 amino acids of human intestinal ALP, as determined by direct protein sequencing. Intestinal ALP shows 86.5% amino acid identity to placental (type 1) ALP and 56.6% amino acid identity to liver/bone/kidney ALP. In the 3'-untranslated regions, intestinal and placental ALP cDNAs are 73.5% identical (excluding gaps). The evolution of this multigene enzyme family is discussed

  13. Human placental alkaline phosphatase in liver and intestine

    International Nuclear Information System (INIS)

    Three distinct forms of human alkaline phosphatase, presumably isozymes, are known, each apparently associated with a specific tissue. These are placental, intestinal, and liver (kidney and bone). The authors have used a specific immunoassay and HPLC to show that placental alkaline phosphatase is also present in extracts of liver and intestine in appreciable amounts

  14. Space-time variability of alkalinity in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    G. Cossarini

    2014-09-01

    Full Text Available The paper provides a basin assessment of the spatial distribution of ocean alkalinity in the Mediterranean Sea. The assessment is made using a 3-D transport-biogeochemical-carbonate model to integrate the available experimental findings, which also constrains model output. The results indicate that the Mediterranean Sea shows alkalinity values that are much higher than those observed in the Atlantic Ocean on a basin-wide scale. A marked west-to-east surface gradient of alkalinity is reproduced as a response to the terrestrial discharges, the mixing effect with the Atlantic water entering from the Gibraltar Strait and the Black Sea water from Dardanelles, and the surface flux of evaporation minus precipitation. Dense water production in marginal seas (Adriatic and Aegean Seas, where alkaline inputs are relevant, and the Mediterranean thermohaline circulation sustains the west-to-east gradient along the entire water column. In the surface layers, alkalinity has a relevant seasonal cycle (up to 40 μmol kg−1 that is driven both by physical and biological processes. A comparison of alkalinity vs. salinity indicates that different regions present different relationships. In regions of freshwater influence, the two measures are negatively correlated due to riverine alkalinity input, whereas they are positively correlated in open seas. Alkalinity always is much higher than in the Atlantic waters, which might indicate a higher than usual buffering capacity towards ocean acidification, even at high concentrations of dissolved inorganic carbon.

  15. Comparative Detection of Alkaline Protease Production in Exiguobacterium acetylicum

    International Nuclear Information System (INIS)

    Alkaline protease is one of the most important enzymes in industry, medicine, and research. In the present work, a comparative detection for alkaline protease activity was established for instant detection of enzyme activity. Eight different alkalophilic bacterial isolates were compared based on the clear zone they produced on skim milk agar. One strain gave an absolute clear zone in 16 hours and was used for alkaline protease detection. The result of Phenotypic identification using Biology Microlog 3 identified the isolate as Exiguobacterium acetylicum. The isolate under study showed slightly different characteristics from a known Exiguobacterium acetylicum strain. The isolate tolerated alkaline conditions up to ph 11, while good growth was evident at ph 7, the maximum alkaline protease activity was observed at ph 9 which reached up to 109.01 U/ml. The alkaline activity assay using alkaline protease enzyme assay were coordinating with those obtained by conductivity; there was a relevant decrease in conductivity at the maximum increase in enzyme activity, which proved the cell membrane conductivity has a close relation to alkaline protease production. This isolate has tolerated gamma radiation, the increase in dose (up to 4 Gy) gave wider clear zones in terms of diameter and this was relevant to the conductivity measurements

  16. Geochemical aspects of alkaline massif of Banhadao, PR, Brazil

    International Nuclear Information System (INIS)

    The alkaline massif of Banhadao, located near Cerro Azul, State of Parana, southern Brazil, occupies an area of about 8 Km2 and is constituted by three magnetic associations: a group of mesocratic to leucocratic coarse nepheline syenites (NeS) (melanite NeS, NeS I, and light reddish and grey varieties of NeS II); a second group of medium to fine-grained ultrabasic to basic rocks (phlogopite melteigites and petrologically related malignites and feldspar-melanite ijolites); and a group of fine-grained to aphanitic phonolotic dikes, cutting NeS. The rocks of the complex are miaskitic, showing low concentrations of trace elements (V, Th and mainly REE), lack of rare metal silicates, and relative abundance of apatite and sphene. NeS are distinguished by a differentiation trend in which highly differentiated end members are enriched in alkalis and Al2O3, with decrease in MgO, FeO (total), CaO and TiO2. The less differentiated melanite-rich rocks show higher concentrations in Zr, Nb, Y and V. Phlogopite melteigites and associated rocks show the highest contents of MgO, FeO (total), CaO and TiO2, and the lowest concentration of alkalis and Al2O3; they are significantly enriched in Ba and are the only rocks with detectable amounts of Ni, Cu and Cr. The phonolites are chemically similar to NeS. The Banhadao rocks were probably formed during successive intrusions of two different magmas types. The source of NeS and phonolites was probably a nephelinitic magma, while phlogopite melteigites and related rocks were probably derived from an alkali-enriched ferromagnesian magna. Both parent magmas probably derived by melting of rocks of the lower crust or upper mantle. (author)

  17. Perfect Dispersive Medium

    CERN Document Server

    Gupta, Shulabh

    2015-01-01

    Dispersion is at the heart of all ultrafast real-time signal processing systems across the entire electromagnetic spectrum ranging from radio-frequencies to optics. However, following Kramer-Kronig relations, these signal processing systems have been plagued with the parasitic amplitude distortions due to frequency dependent, and non-flat amplitude transmission of naturally dispersive media. This issue puts a serious limitation on the applicability and performance of these signal processing systems. To solve the above mentioned issue, a perfect dispersive medium is proposed in this work, which artificially violates the Kramer-Kronig relations, while satisfying all causality requirements. The proposed dispersive metamaterial is based on loss-gain metasurface pairs and exhibit a perfectly flat transmission response along with arbitrary dispersion in a broad bandwidth, thereby solving a seemingly unavoidable issue in all ultrafast signal processing systems. Such a metamaterial is further shown using sub-waveleng...

  18. Spiegel. Medium. Kunst

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    to human talent, came the millennia of untiring labours and the play of art and science and thought. The human love-affair with reflection (to cite Mark Pendergast’s subtitle - Mirror/Mirror: A History of the Human Love Affair with Reflection [New York 2003]) has always been a platonic one and I hold...... that this is what has assured its multifarious prolongation in art, the humanities, the sciences. This affair was definitely also a narcissistic one, but notwithstanding, that aspect does not constitute the major subject of this book for various reasons. Investigation of the mirror phenomenon in humanities research...... has hitherto focussed on the generation of the sense of self and of ‘consciousness’ – explicitly and primarily so. As a medium of self-knowledge, the mirror’s self-reference set the limit to its scholarly apprehension – self-reference as the great subject of all psycho-analytically informed approaches...

  19. Nuclear medium effects in $\

    CERN Document Server

    Haider, H; Athar, M Sajjad; Vacas, M J Vicente

    2011-01-01

    Nuclear medium effects in the weak structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ have been studied for deep inelastic neutrino/antineutrino reactions in iron nucleus by taking into account Fermi motion, binding, pion and rho meson cloud contributions, target mass correction, shadowing and anti-shadowing corrections. The calculations have been performed in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations. Using these structure functions we have obtained the ratio $R_{F2,F3}^A(x,Q^2)= \\frac{2F_{2,3}^A(x,Q^2)}{AF_{2,3}^D(x,Q^2)}$, the differential scattering cross section $\\frac{1}{E}\\frac{d^2\\sigma}{dxdy}$ and the total scattering cross section $\\sigma$. The results of our numerical calculations in $^{56}Fe$ are compared with the experimental results of NuTeV and CDHSW collaborations.

  20. Synergistic degradation of konjac glucomannan by alkaline and thermal method.

    Science.gov (United States)

    Jin, Weiping; Mei, Ting; Wang, Yuntao; Xu, Wei; Li, Jing; Zhou, Bin; Li, Bin

    2014-01-01

    The application of konjac glucomannan (KGM) in the food industry is always limited by its high viscosity. Hereby, low-viscosity KGM was prepared by alkaline-thermal degradation method. This process was demonstrated by the changes of average molecular weight and a kinetic model was developed. The results revealed that high alkalinity and high temperature had a synergetic effect on degradation. The structure of hydrolysates was evaluated by periodate oxidation and their fluidly properties were researched by rheology measurements. The degradation was divided into two regimes. The rate of the first regime (within 1h) is higher than that of the second one (last 1h). It is found that alkaline hydrolysis and deacetylation have a synergistic effect on the degradation under high alkalinity (pH 9.2) and low temperature condition (25 °C). Finally, rheology parameters showed alkaline-thermal degradation is a promising way that can be applied in practice to degrade KGM. PMID:24274506

  1. Phosphatidylinositol anchor of HeLa cell alkaline phosphatase

    International Nuclear Information System (INIS)

    Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either 3H-fatty acids or [3H]ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the 3H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of [3H]ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from 3H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the 3H-fatty acid and the [3H]ethanolamine label from purified alkaline phosphatase. Subtilisin was also able to remove the [3H]ethanolamine label from the purified alkaline phosphatase. The 3H radioactivity in alkaline phosphatase purified from [3H]ethanolamine-labeled cells comigrated with authentic [3H]ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the 3H-fatty acid and [3H]ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase

  2. Phosphatidylinositol anchor of HeLa cell alkaline phosphatase

    Energy Technology Data Exchange (ETDEWEB)

    Jemmerson, R.; Low, M.G.

    1987-09-08

    Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either /sup 3/H-fatty acids or (/sup 3/H)ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the /sup 3/H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of (/sup 3/H)ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from /sup 3/H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the /sup 3/H-fatty acid and the (/sup 3/H)ethanolamine label from purified alkaline phosphatase. Subtilisin was also able to remove the (/sup 3/H)ethanolamine label from the purified alkaline phosphatase. The /sup 3/H radioactivity in alkaline phosphatase purified from (/sup 3/H)ethanolamine-labeled cells comigrated with authentic (/sup 3/H)ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the /sup 3/H-fatty acid and (/sup 3/H)ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase.

  3. The Effect of Alkaline Material Particle Size on Adjustment Ability of Buffer Capacity

    Directory of Open Access Journals (Sweden)

    Girts Bumanis

    2015-09-01

    Full Text Available The pH control in biotechnological processes like anaerobic digestion is one of the key factors to ensure high efficiency in the biogas production process. The decrease of pH level in the digestion process occurs due to the rapid acid formation during metabolic processes of bacteria which leads to the inhibition of the methane producing bacteria; therefore further digestion process is limited. The efficiency of anaerobic digestion reactor decreases dramatically if the pH level falls under pH 6.6. This problem is common for single-stage continuous digesters with a high organic solid content; therefore the active pH controlling method is commonly used. By creating inorganic alkaline material, the passive pH controlling system could be created. Soluble alkalis are enclosed in the matrix of material during the activation process thus providing slow leaching of free alkalis from the material structure in water medium and ensuring pH increase. In this research a porous alkaline composite material was developed as a pH controlling agent for the biogas production. Two mixture compositions with a different Si/Al and Si/Na ratio were created. The effect of particle size of the material was investigated in order to provide different leaching rates for the described material. Granular material with particle fractions 1/2 mm, 2/4 mm and 4/8 mm and a cubical specimen with dimensions 20×20×20 mm were tested. The pH level of water medium increased up to pH 11.6 during the first day and final pH value decreased to 7.8 after 20-day leaching. Alkali leaching can be increased by 19-32% changing the mixture composition by adding glass powder to the alkaline material. The particle size factor was negligible for leaching rate of alkaline material due to the high porosity of material. Research results show that this composite material has a potential to be applied in pH control for biotechnological purposes.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7325

  4. Changes in Expression of Connexin 32, Bile Canaliculus-Like Structures, and Localization of Alkaline Phosphatase in Primary Cultures of Fetal Rat Hepatocytes

    International Nuclear Information System (INIS)

    We devised an experimental design in primary cultures of fetal rat hepatocytes for studying hepatocyte differentiation over a short period. In the present study, hepatocytes were first cultured for 3 days in dexamethasone-supplemented medium and then for an additional 3 days in dexamethasone- or epidermal growth factor-supplemented medium. In hepatocytes cultured continuously in dexamethasone-supplemented medium, the expression of connexin 32 increased and bile canaliculus-like structures and localization of alkaline phosphatase in the plasma membrane around bile canaliculus-like structures were maintained. Few cells incorporated bromodeoxyuridine. On the other hand, in most of the hepatocytes cultured in epidermal growth factor-supplemented medium, the expression of connexin 32 was minimally recognized, bile canaliculus-like structures were shortened or eliminated, and alkaline phosphatase was localized as numerous fine spots throughout the cytoplasm. More than 20% of all hepatocytes incorporated bromodeoxyuridine. The present study suggests that in hepatocytes, there is a close relationship among connexin 32 expression, the maintenance of bile canaliculus-like structures, and the localization of alkaline phosphatase to the plasma membrane around the bile canaliculus-like structures, and this indicates that the present experimental model is useful for studying hepatocyte differentiation over a short period

  5. The Intergalactic Medium

    CERN Document Server

    Madau, P

    2000-01-01

    About half a million years after the Big Bang, the ever-fading cosmic blackbody radiation cooled below 3000 K and shifted first into the infrared and then into the radio, and the smooth baryonic plasma that filled the Universe became neutral. The Universe then entered a ``dark age'' which persisted until the first cosmic structures collapsed into gravitationally-bound systems, and evolved into stars, galaxies, and black holes that lit up the Universe again. Some time between redshift of 7 and 15, stars within protogalaxies created the first heavy elements; these systems, together perhaps with an early population of quasars, generated the ultraviolet radiation that reheated and reionized the cosmos. The history of the Universe during and soon after these crucial formative stages is recorded in the all-pervading intergalactic medium (IGM), which is believed to contain most of the ordinary baryonic material left over from the Big Bang. Throughout the epoch of structure formation, the IGM becomes clumpy and acqui...

  6. Titratable Acidity and Alkalinity of Red Soil Surfaces

    Institute of Scientific and Technical Information of China (English)

    SHAOZONG-CHEN; HEQUN; 等

    1993-01-01

    The surfaces of red soils have an apparent amphoteric character,carrying titratable acidity and titratable alkalinity simultaneously.The titratable acidity arises from deprotonation of hydroxyl groups of hydrous oxide-type surfaces and dissociation of weak-acid functional groups of soil organic matter,while the titratable alkalinity is derived from release of hydroxyl groups of hydrous oxide-type surfaces.The titratable acidity and titratable alkalinity mainly depended on the composition and content of iron and aluminum oxides in the soils.The results showed that the titratable acidity and titratable alkalinity were in significantly positive correlation not only with the content of amorphous aluminum oxide(Alo) and iron oxide(Feo) extracted with acid ammonium oxalate solution,free iron oxide(Fed) extracted with sodium dithionite-citrate-bicarbonate(DCB) and clays,but also with the zero point of charge (ZPC) of the samples.Organic matter made an important contribution to the titratable acidity.the titratable alkalinity was closely correlated with the amount of fluoride ions adsorbed.The titratable acidity and titratable alkalinity of red soils were influenced by parent materials,being in the order of red soil derived from basalt> that from tuff> that from granite.The titratable acidity and titratable alkalinity ware closely related with origination of the variable charges of red soils,and to a certain extent were responsible for variable negative and positive charges of the soils.

  7. 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

    The overall purpose of this project has been to contribute to this load management by developing a 2{sup nd} generation of alkaline electrolysis system characterized by being compact, reliable, inexpensive and energy efficient. The specific targets for the project have been to: 1) Increase cell efficiency to more than 88% (according to the higher heating value (HHV)) at a current density of 200 mA /cm{sup 2}; 2) Increase operation temperature to more than 100 degree Celsius to make the cooling energy more valuable; 3) Obtain an operation pressure more than 30 bar hereby minimizing the need for further compression of hydrogen for storage; 4) Improve stack architecture decreasing the price of the stack with at least 50%; 5) Develop a modular design making it easy to customize plants in the size from 20 to 200 kW; 6) Demonstrating a 20 kW 2{sup nd} generation stack in H2College at the campus of Arhus University in Herning. The project has included research and development on three different technology tracks of electrodes; an electrochemical plating, an atmospheric plasma spray (APS) and finally a high temperature and pressure (HTP) track with operating temperature around 250 deg. C and pressure around 40 bar. The results show that all three electrode tracks have reached high energy efficiencies. In the electrochemical plating track a stack efficiency of 86.5% at a current density of 177mA/cm{sup 2} and a temperature of 74.4 deg. C has been shown. The APS track showed cell efficiencies of 97%, however, coatings for the anode side still need to be developed. The HTP cell has reached 100 % electric efficiency operating at 1.5 V (the thermoneutral voltage) with a current density of 1. 1 A/cm{sup 2}. This track only tested small cells in an externally heated laboratory set-up, and thus the thermal loss to surroundings cannot be given. The goal set for the 2{sup nd} generation electrolyser system, has been to generate 30 bar pressure in the cell stack. An obstacle to be

  8. Anodic stripping voltammetry of technetium alkaline media

    International Nuclear Information System (INIS)

    A method of direct determination of technetium in 0.1 M NaOH by anodic stripping voltametry at glassy carbon electrode has been elaborated. The peak height of anodic TcO2(OH)2 dissolution was found to be linearly dependent on preconcentration time, and the concentration of technetium in the range 5.0 * 10-8 -6 M. The detection limit for the Tc determination by ASV technique under study was found to be 5.0 * 10-8 M with standard deviation 5-7% (p2(OH)2 anodic dissolution peak current. Addition of 1.0* 10-6 M U(UI) to the sample solution was found to shift the peak of the TcO2(OH)2 100 mV towards negative direction and disturb the linearity of the calibration curve. Therefore; for a successful application of the developed ASV technique for Tc determination in the alkaline media, uranium should be removed from the analyte before determination

  9. Response of Desulfovibrio vulgaris to Alkaline Stress

    Energy Technology Data Exchange (ETDEWEB)

    Stolyar, S.; He, Q.; He, Z.; Yang, Z.; Borglin, S.E.; Joyner, D.; Huang, K.; Alm, E.; Hazen, T.C.; Zhou, J.; Wall, J.D.; Arkin, A.P.; Stahl, D.A.

    2007-11-30

    The response of exponentially growing Desulfovibrio vulgarisHildenborough to pH 10 stress was studied using oligonucleotidemicroarrays and a study set of mutants with genes suggested by microarraydata to be involved in the alkaline stress response deleted. The datashowed that the response of D. vulgaris to increased pH is generallysimilar to that of Escherichia coli but is apparently controlled byunique regulatory circuits since the alternative sigma factors (sigma Sand sigma E) contributing to this stress response in E. coli appear to beabsent in D. vulgaris. Genes previously reported to be up-regulated in E.coli were up-regulated in D. vulgaris; these genes included three ATPasegenes and a tryptophan synthase gene. Transcription of chaperone andprotease genes (encoding ATP-dependent Clp and La proteases and DnaK) wasalso elevated in D. vulgaris. As in E. coli, genes involved in flagellumsynthesis were down-regulated. The transcriptional data also identifiedregulators, distinct from sigma S and sigma E, that are likely part of aD. vulgaris Hildenborough-specific stress response system.Characterization of a study set of mutants with genes implicated inalkaline stress response deleted confirmed that there was protectiveinvolvement of the sodium/proton antiporter NhaC-2, tryptophanase A, andtwo putative regulators/histidine kinases (DVU0331 andDVU2580).

  10. Magic wavelengths in the alkaline earth ions

    CERN Document Server

    Kaur, Jasmeet; Arora, Bindiya; Sahoo, B K

    2015-01-01

    We present magic wavelengths for the $nS$ - $nP_{1/2,3/2}$ and $nS$ - $mD_{3/2,5/2}$ transitions, with the respective ground and first excited $D$ states principal quantum numbers $n$ and $m$, in the Mg$^+$, Ca$^+$, Sr$^+$ and Ba$^+$ alkaline earth ions for linearly polarized lights by plotting dynamic polarizatbilities of the $nS$, $nP_{1/2,3/2}$ and $mD_{3/2,5/2}$ states of the ions. These dynamic polarizabilities are evaluated by employing a relativistic all-order perturbative method and their accuracies are ratified by comparing their static values with the available high precision experimental or other theoretical results. Moreover, some of the magic wavelengths identified by us in Ca$^+$ concurs with the recent measurements reported in [{\\bf Phys. Rev. Lett. 114, 223001 (2015)}]. Knowledge of these magic wavelengths are propitious to carry out many proposed high precision measurements trapping the above ions in the electric fields with the corresponding frequencies.

  11. Solubility of pllutonium in alkaline salt solutions

    International Nuclear Information System (INIS)

    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

  12. Radioimmunoassay of human intestinal alkaline phosphatase

    International Nuclear Information System (INIS)

    A new method of radioimmunoassay using the double antibody method for human intestinal alkaline phosphatase (ALP) was first elaborated. The following results were obtained: 1) In this system, the optimal antibody concentration is 10,000 times the dilution of the original anti-serum, and the optimal assay range is 0.5 to 25 ng. Enzymatic activity of 1 ng intestinal ALP is 4.1 King-Armstrong units. 2) In this system, the sera including intestinal ALP are divided to two groups. One group shows a dose response curve similar to that of purified intestinal ALP, and the other shows a lesser one. This reason is not clear. Hepatic ALP, osseous ALP and placental ALP in the sera show no response in this system. 3) In this system, the B/T value of 50 μg of purified human placental ALP is almost equal to 1 ng of purified human intestinal ALP. Similarly, the B/T value of 50 μg of purified human intestinal ALP is equal to almost 5 ng of purified human placental ALP. This shows that cross-reaction exists between intestinal and placental ALPs at high concentrations. (J.P.N.)

  13. Revisiting zinc passivation in alkaline solutions

    International Nuclear Information System (INIS)

    Highlights: • Zinc passive films were characterised by electrochemical tests coupled with cross sectional FIB-SEM. • Passive layers at pH > 12 comprised of an outer precipitated layer and inner compact oxide. • The electrolyte pH influences the nature/stability of the outer precipitated layer and this impacts the passive state on zinc. • The precipitated layers on zinc at pH 12 support cathode reactions and catalyse oxide growth. -- Abstract: Passive films nominally consist of an inner compact oxide and the outer precipitated layer. In the case of zinc (Zn), the outer layer is mainly precipitated ZnO/Zn(OH)2. Electrolyte pH controls the stability of the outer precipitated layer. In a pH 13 solution, formation of soluble Zn(OH)3− and Zn(OH)42− phases render the precipitated layer unstable increasing zinc corrosion, whereas at pH 12, the precipitated layer (ZnO/Zn(OH)2) is more stable making it an effective anodic barrier upon zinc. These precipitated oxides formed at pH 12 support cathodic reactions on their surface which in turn catalyse further oxide growth by a cathodically driven process. Focused ion beam-scanning electron microscopy (FIB-SEM) was used to support some of the electrochemical assertions, revealing the form and morphology of the passive layers that grow upon zinc exposed to alkaline solutions

  14. Alkaline lipase of glyoxysomes is a glycoprotein

    International Nuclear Information System (INIS)

    In castor bean endosperm, the glyoxysomal alkaline lipase is an intrinsic membrane protein. At four days post-germination, the enzyme is also present in the endoplasmic reticulum where it accounts for approximately 15% of total activity. The active enzyme was purified by Maeshima and Beevers from isolated glyoxysomes. Specific antibodies to the 62 kD subunit were raised in rabbits. The anti-lipase has been used in preliminary experiments to determine the relationship between the lipase of the glyoxysomal membrane and the ER. Results indicate the presence of 3 cross-reacting antigens in carbonate-washed ER and glyoxysomal membranes. The 62 kD subunit, found predominantly in glyoxysomes, was eluted form Con-A Sepharose by 0.5 M α-methylglucoside. An 86kD form present in 2-d ER (but not in 4-d ER) and glyoxysomes did not bind Con-A Sepharose. This form appears to be an unglycosylated precursor or the 62 kD subunit. A 67 kD form was the only species seen in 4-d ER. In a time course experiment, the 67 kD form appeared on the glyoxysomal membrane

  15. The aluminum chemistry and corrosion in alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jinsuo [International Nuclear System Engineering, MS-K 575, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)], E-mail: jszhang@lanl.gov; Klasky, Marc; Letellier, Bruce C. [International Nuclear System Engineering, MS-K 575, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2009-02-15

    Aluminum-alkaline solution systems are very common in engineering applications including nuclear engineering. Consequently, a thorough knowledge of the chemistry of aluminum and susceptibility to corrosion in alkaline solutions is reviewed. The aluminum corrosion mechanism and corrosion rate are examined based on current experimental data. A review of the phase transitions with aging time and change of environment is also performed. Particular attention is given to effect of organic and inorganic ions. As an example, the effect of boron is examined in detail because of the application in nuclear reactor power systems. Methods on how to reduce the corrosion rate of aluminum in alkaline solutions are also highlighted.

  16. Kinetic and Mechanistic Studies of Oxidation of an Antiallergic Drug with Bromamine-T in Acid and Alkaline Media

    International Nuclear Information System (INIS)

    Cetrizine dihydrochloride (CTZH) is widely used as an anti-allergic drug. Sodium N-bromo-p-toluenesulfonamide or bromamine-T (BAT) is the bromine analogue of chloramine-T (CAT) and is found to be a better oxidizing agent than CAT. In the present research, the kinetics of oxidation of CTZH with BAT in acid and alkaline media was studied at 313 K. The experimental rate laws obtained are: -d[BAT]/dt = k[BAT] [CTZH]0.80[H+]-0.48 in acid medium and -d[BAT]/dt = k[BAT][CTZH]0.48[OH-]0.52[PTS]-0.40 in alkaline medium where PTS is p-toluenesulfonamide. Activation parameters and reaction constants were evaluated. The solvent isotope effect was studied using D2O. The dielectric effect is positive. The stoichiometry of the reaction was found to be 1:1 and the oxidation products were identified as 4-chlorobenzophenone and (2-piperazin-1-yl-ethoxy)-acetic acid in both media. The rate of oxidation of CTZH is faster in acid medium. Suitable mechanisms and related rate laws have been worked out

  17. Kinetic, mechanistic and spectral investigation of ruthenium (III)-catalysed oxidation of atenolol by alkaline permanganate (stopped-flow technique)

    Indian Academy of Sciences (India)

    Rahamatalla M Mulla; Gurubasavaraj C Hiremath; Sharanappa T Nandibewoor

    2005-01-01

    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 (atenolol : KMnO4). The reaction shows first-order dependence on [permanganate] and [ruthenium (III)] and apparently less than unit order on both atenolol and alkali concentrations. Reaction rate decreases with increase in ionic strength and increases with decreasing dielectric constant of the medium. Initial addition of reaction products does not affect the rate significantly. A mechanism involving the formation of a complex between catalyst and substrate has been proposed. The active species of ruthenium (III) is understood as [Ru(H2O)5OH]2+. The reaction constants involved in the different steps of mechanism are calculated. Activation parameters with respect to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated.

  18. Nordic Seas total alkalinity data in CARINA

    Directory of Open Access Journals (Sweden)

    A. Olsen

    2009-08-01

    Full Text Available Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic. The data have been subject to rigorous quality control (QC in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS, the Atlantic (ATL and the Southern Ocean (SO. With the adjustments the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004 and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. The Arctic Mediterranean Seas includes the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. This contribution presents an account of the quality control of the total alkalinity (ALK data from the Nordic Seas in CARINA. Out of the 35 cruises from the Nordic Seas included in CARINA, 21 had ALK data. The data from 6 of these were found to be of low quality and should not be used. Of the others, 3 were found to be biased low and were subject to adjustment. Thus the final CARINA data product contains ALK data from 15 cruises from the Nordic Seas, and these data appear consistent to ±3 μmol kg−1.

  19. Chlorine solubility in evolved alkaline magmas

    Directory of Open Access Journals (Sweden)

    M. R. Carroll

    2005-06-01

    Full Text Available Experimental studies of Cl solubility in trachytic to phonolitic melts provide insights into the capacity of alkaline magmas to transport Cl from depth to the earth?s surface and atmosphere, and information on Cl solubility variations with pressure, temperature and melt or fluid composition is crucial for understanding the reasons for variations in Cl emissions at active volcanoes. This paper provides a brief review of Cl solubility experiments conducted on a range of trachytic to phonolitic melt compositions. Depending on the experimental conditions the melts studied were in equilibrium with either a Cl-bearing aqueous fluid or a subcritical assemblage of low- Cl aqueous fluid + Cl-rich brine. The nature of the fluid phase(s was identified by examination of fluid inclusions present in run product glasses and the fluid bulk composition was calculated by mass balance. Chlorine concentrations in the glass increase with increasing Cl molality in the fluid phase until a plateau in Cl concentration is reached when melt coexists with aqueous fluid + brine. With fluids of similar Cl molality, higher Cl concentrations are observed in peralkaline phonolitic melts compared with peraluminous phonolitic melts; overall the Cl concentrations observed in phonolitic and trachytic melts are approximately twice those found in calcalkaline rhyolitic melts under similar conditions. The observed negative pressure dependence of Cl solubility implies that Cl contents of melts may actually increase during magma decompression if the magma coexists with aqueous fluid and Cl-rich brine (assuming melt-vapor equilibrium is maintained. The high Cl contents (approaching 1 wt% Cl observed in some melts/glasses from the Vesuvius and Campi Flegrei areas suggest saturation with a Cl-rich brine prior to eruption.

  20. The Martian ocean: First acid, then alkaline

    Science.gov (United States)

    Schaefer, M. W.

    1992-01-01

    In Mars' distant past, carbon dioxide and water may have been plentiful. Values of total outgassed CO2 from several to about 10 bar are consistent with present knowledge, and this amount of CO2 implies an amount of water outgassed equal to an equivalent depth of 500 to 1000 m. It is quite reasonable, therefore, to envision an early Mars in which there was a body or bodies of liquid water, perhaps in the northern plains, and a dense carbon dioxide atmosphere. Under such conditions, the pH of the water will be low, due to the dissolution of carbon dioxide in the water to form carbonic acid. This acidic water is capable of weathering the available rock quite intensely, particularly because this rock is likely to be heavily fractured (from meteorite bombardment) or even consist of fine particles (such as pyroclastic deposits). As time goes on, however, the carbon dioxide atmosphere will rapidly pass through the ocean to form carbonate deposits. As the density of the atmosphere decreases, so will the flux of carbonic acid into the ocean. Without this input of carbonic acid, the effect of the dissolved weathering products will be to increase the pH of the water. The ocean will then become alkaline. To study this process, I have developed a geochemical cycle model for the atmosphere-hydrosphere-regolith system of Mars. The treatment of geochemical cycles as complex kinetic chemical reactions has been undertaken for terrestrial systems in recent years with much success. This method is capable of elegantly handling the interactions between the simultaneous chemical reactions needed to understand such a system.

  1. Sulfate—Exchange Alkalinity of Ferralsol Colloid

    Institute of Scientific and Technical Information of China (English)

    ZHANGGANGYA; ZHANGXIAONIAN

    1999-01-01

    The amount of OH- replaced by sulfate,i.e.,sulfate-exchange alkalinity,from the electric double layer of ferralsol colloid was measured quantitatively in different conditions with an automatic titration equipment.The amount of OH- release increased with the amount of Na2SO4 added and decreased with raising pH in the suspension of ferralsol colloid.The exchange acidity was displayed as pH was higher than 5.6,If the negative effect of sodium ions was offset,the amount of OH- replaced by sulfate was larger than the original amount of OH- released in the pH range of lower than 5.8.The amount of OH- released decreased rapidly as pH was higher than 6.0 and dropped to zero when pH reached 6.5.In the solution of 2.0molL-1 NaClO4,the amount of OH- repleaced by sulfate from the surface of ferralsol colloid could be considered as the amount of OH- adsorbed by ligand exchange reaction.The amount of OH- released in the solution of NaClO4 concentration below 2.0mol L-1 from which the amount of OH- adsorbed by ligand exchange reaction was subtracted could be conidered as the OH- adsorbed by electrostatic force,The OH- adsorbed by electrostatic force decreased with increases in the concentration of NaClO4 and pH and increased almost linearly with the increasing amount of Na2SON4 added.The percentages of OH- adsorbed by electrostatic force in water and in the electrolyte solutions of 0.05 and 0.5mol L-1 NaClO4 in the total OH- released were calculated,respectively.

  2. Upper medium segment cooling down

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The sluggish growth of the passenger car market in top provinces was also reflected in a depression of the upper medium segment. In Jan-Apr, 2008, the top 3 upper medium models accounting for nearly 40% of this segment performed poorly, with the Passat-Lingyu and the Accord decreasing. The Camry also saw a decrease in three top provinces: Guangdong,

  3. Mesons in the nuclear Medium

    OpenAIRE

    Kotulla, Martin

    2006-01-01

    We discuss recent experimental results on the modification of hadron properties in a nuclear medium. Particular emphasis is placed on an $\\omega$ production experiment performed by the CBELSA/TAPS collaboration at the ELSA accelerator. The data shows a smaller $\\omega$ meson mass together with a significant increase of its width in the nuclear medium.

  4. Concentration and separation of vanadium from alkaline media by strong alkaline anion-exchange resin 717

    Institute of Scientific and Technical Information of China (English)

    HUANG Jinwen; SU Peng; WU Wenwei; LIAO Sen; QIN Huiquan; WU Xuehang; HE Xiaohu; TAO Liujia; FAN Yanjin

    2010-01-01

    With strong alkaline anion-exchange resin 717 as the sorbent and NaOH solution as the eluent, a study on the sorption from alkaline solution and elution of vanadium(Ⅴ), silicon(Ⅳ), and aluminium(Ⅲ) was carried out. Different parameters affecting the sorption and elution process,including temperature, pH values as well as the ratio of resin to solution, were investigated. The results show that sorption degree of vanadium(Ⅴ) increases with a decrease of pH values, and V(Ⅴ) ions are easier sorbed than Si(Ⅳ) and Al(Ⅲ) ions under the same conditions. The sorption degree of V(Ⅴ), Si(Ⅳ), and Al(Ⅲ) at pH 9.14 for 15 min are 90.6%, 33.5%, and 21.6%, respectively. Si(Ⅳ), Al(Ⅲ), and V(Ⅴ) ions sorbed on 717 resin were eluted by use of 2 mol.L-1 NaOH solution; the desorption degree of V(Ⅴ), Si(Ⅳ), and Al(Ⅲ) for 5 min are 81.7 %,99.1%, and 99.3%, respectively.

  5. Enhanced Thermostability of a Fungal Alkaline Protease by Different Additives

    OpenAIRE

    Nilesh P. Nirmal; R. Seeta Laxman

    2014-01-01

    A fungal strain (Conidiobolus brefeldianus MTCC 5184) isolated from plant detritus secreted a high activity alkaline protease. Thermostability studies of the fungal alkaline protease (FAP) revealed that the protease is stable up to 50°C with 40% residual activity after one hour. Effect of various additives such as sugars, sugar alcohols, polyols, and salts, on the thermostability of FAP was evaluated. Among the additives tested, glycerol, mannitol, xylitol, sorbitol, and trehalose were found ...

  6. A study of extracting uranium by intensified alkaline heap leaching

    International Nuclear Information System (INIS)

    A new technique of extracting uranium by intensified alkaline heap leaching was presented to treat a uranium ore of high carbonate content. A lixiviant, high concentration of alkaline solution, reacts with the ore prior to heap making for some time at a certain temperature,reducing the leaching time remarkably. With this technique, the leaching rate of uranium increased from 50% to 90% or above and the leaching time decreased from 64 days to 12 days. (authors)

  7. Enhanced alkaline hydrolysis and biodegradability studies of nitrocellulose-bearing missile propellant

    Science.gov (United States)

    Sidhoum, Mohammed; Christodoulatos, Christos; Su, Tsan-Liang; Redis, Mercurios

    1995-01-01

    Large amounts of energetic materials which have been accumulated over the years in various manufacturing and military installations must be disposed of in an environmentally sound manner. Historically, the method of choice for destruction of obsolete or aging energetic materials has been open burning or open detonation (OB/OD). This destruction approach has become undesirable due to air pollution problems. Therefore, there is a need for new technologies which will effectively and economically deal with the disposal of energetic materials. Along those lines, we have investigated a chemical/biological process for the safe destruction and disposal of a double base solid rocket propellant (AHH), which was used in several 8 inch projectile systems. The solid propellant is made of nitrocellulose and nitroglycerin as energetic components, two lead salts which act as ballistic modifiers, triacetin as a plasticizer and 2-Nitrodiphenylamine (2-NDPA) as a stabilizer. A process train is being developed to convert the organic components of the propellant to biodegradable products and remove the lead from the process stream. The solid propellant is first hydrolyzed through an enhanced alkaline hydrolysis process step. Following lead removal and neutralization, the digested liquor rich in nitrates and nitrites is found to be easily biodegradable. The digestion rate of the intact ground propellant as well as the release of nitrite and nitrate groups were substantially increased when ultrasound were supplied to the alkaline reaction medium compared to the conventional alkaline hydrolysis. The effects of reaction time, temperature, sodium hydroxide concentration and other relevant parameters on the digestion efficiency and biodegradability have been studied. The present work indicates that the AHH propellant can be disposed of safely with a combination of physiochemical and biological processes.

  8. A fungal pathogen secretes plant alkalinizing peptides to increase infection.

    Science.gov (United States)

    Masachis, Sara; Segorbe, David; Turrà, David; Leon-Ruiz, Mercedes; Fürst, Ursula; El Ghalid, Mennat; Leonard, Guy; López-Berges, Manuel S; Richards, Thomas A; Felix, Georg; Di Pietro, Antonio

    2016-01-01

    Plant infections caused by fungi are often associated with an increase in the pH of the surrounding host tissue(1). Extracellular alkalinization is thought to contribute to fungal pathogenesis, but the underlying mechanisms are poorly understood. Here, we show that the root-infecting fungus Fusarium oxysporum uses a functional homologue of the plant regulatory peptide RALF (rapid alkalinization factor)(2,3) to induce alkalinization and cause disease in plants. An upshift in extracellular pH promotes infectious growth of Fusarium by stimulating phosphorylation of a conserved mitogen-activated protein kinase essential for pathogenicity(4,5). Fungal mutants lacking a functional Fusarium (F)-RALF peptide failed to induce host alkalinization and showed markedly reduced virulence in tomato plants, while eliciting a strong host immune response. Arabidopsis plants lacking the receptor-like kinase FERONIA, which mediates the RALF-triggered alkalinization response(6), displayed enhanced resistance against Fusarium. RALF homologues are found across a number of phylogenetically distant groups of fungi, many of which infect plants. We propose that fungal pathogens use functional homologues of alkalinizing peptides found in their host plants to increase their infectious potential and suppress host immunity. PMID:27572834

  9. Anaerobic digestion of the microalga Spirulina at extreme alkaline conditions: biogas production, metagenome, and metatranscriptome

    Science.gov (United States)

    Nolla-Ardèvol, Vímac; Strous, Marc; Tegetmeyer, Halina E.

    2015-01-01

    A haloalkaline anaerobic microbial community obtained from soda lake sediments was used to inoculate anaerobic reactors for the production of methane rich biogas. The microalga Spirulina was successfully digested by the haloalkaline microbial consortium at alkaline conditions (pH 10, 2.0 M Na+). Continuous biogas production was observed and the obtained biogas was rich in methane, up to 96%. Alkaline medium acted as a CO2 scrubber which resulted in low amounts of CO2 and no traces of H2S in the produced biogas. A hydraulic retention time (HRT) of 15 days and 0.25 g Spirulina L−1 day−1 organic loading rate (OLR) were identified as the optimal operational parameters. Metagenomic and metatranscriptomic analysis showed that the hydrolysis of the supplied substrate was mainly carried out by Bacteroidetes of the “ML635J-40 aquatic group” while the hydrogenotrophic pathway was the main producer of methane in a methanogenic community dominated by Methanocalculus. PMID:26157422

  10. Molecular characterization of alkaline protease of Bacillus amyloliquefaciens SP1 involved in biocontrol of Fusarium oxysporum.

    Science.gov (United States)

    Guleria, Shiwani; Walia, Abhishek; Chauhan, Anjali; Shirkot, C K

    2016-09-01

    An alkaline protease gene was amplified from genomic DNA of Bacillus amyloliquefaciens SP1 which was involved in effective biocontrol of Fusarium oxysporum. We investigated the antagonistic capacity of protease of B. amyloliquifaciens SP1, under in vitro conditions. The 5.62 fold purified enzyme with specific activity of 607.69U/mg reported 24.14% growth inhibition of F. oxysporum. However, no antagonistic activity was found after addition of protease inhibitor i.e. PMSF (15mM) to purified enzyme. An 1149bp nucleotide sequence of protease gene encoded 382 amino acids of 43kDa and calculated isoelectric point of 9.29. Analysis of deduced amino acid sequence revealed high homology (86%) with subtilisin E of Bacillus subtilis. The B. amyloliquefaciens SP1 protease gene was expressed in Escherichiax coli BL21. The expressed protease was secreted into culture medium by E. coli and exhibited optimum activity at pH8.0 and 60°C. The most reliable three dimensional structure of alkaline protease was determined using Phyre 2 server which was validated on the basis of Ramachandran plot and ERRAT value. The expression and structure prediction of the enzyme offers potential value for commercial application in agriculture and industry. PMID:27294522

  11. Nicotine inhibits collagen synthesis and alkaline phosphatase activity, but stimulates DNA synthesis in osteoblast-like cells

    International Nuclear Information System (INIS)

    Use of smokeless tobacco is associated with various oral lesions including periodontal damage and alveolar bone loss. This study was performed to test the effects of nicotine on bone-forming cells at concentrations that occur in the saliva of smokeless tobacco users. Confluent cultures of osteoblast-like cells isolated from chick embryo calvariae were incubated for 2 days with nicotine added to the culture medium (25-600 micrograms/ml). Nicotine inhibited alkaline phosphatase in the cell layer and released to the medium, whereas glycolysis (as indexed by lactate production) was unaffected or slightly elevated. The effects on medium and cell layer alkaline phosphatase were concentration dependent with maximal inhibition occurring at 600 micrograms nicotine/ml. Nicotine essentially did not affect the noncollagenous protein content of the cell layer, but did inhibit collagen synthesis (hydroxylation of [3H]proline and collagenase-digestible protein) at 100, 300, and 600 micrograms/ml. Release of [3H]hydroxyproline to the medium was also decreased in a dose-dependent manner, as was the collagenase-digestible protein for both the medium and cell layer. In contrast, DNA synthesis (incorporation of [3H]thymidine) was more than doubled by the alkaloid, whereas total DNA content was slightly inhibited at 600 micrograms/ml, suggesting stimulated cell turnover. Morphologic changes occurred in nicotine-treated cells including rounding up, detachment, and the occurrence of numerous large vacuoles. These results suggest that steps to reduce the salivary concentration of nicotine in smokeless tobacco users might diminish damaging effects of this product on alveolar bone

  12. New alternative processes for the treatment of the alkaline solvent wash waste

    International Nuclear Information System (INIS)

    The separate treatment of the solvent wash alkaline waste (ASWW) from the other low and medium level liquid wastes generated during reprocessing operations has been investigated through the development of three alternative processes dealing with solvent extraction, chemical precipitation combined with ultrafiltration and inorganic ion exchange. On the basis of lab-scale experiments performed on the same genuine ASWW sample, a comparison has been made between the respective performances of each of these processes in terms of selectivity, decontamination and volume reduction factors. From this assessment, it evolved that solvent extraction and chemical precipitation combined with utrafiltration processes are good competitors for implementing such kind of treatment although for the alpha DF, solvent extraction appears more flexible. To be really attractive, inorganic ion exchange should exhibit better VRF and DF possibly by pretreating the ASWW. 10 refs

  13. The Detection of Alkaline Phosphatase Using an Electrochemical Biosensor in a Single-Step Approach

    Directory of Open Access Journals (Sweden)

    Chung-Chiun Liu

    2009-10-01

    Full Text Available A one-step, single use, disposable Alkaline Phosphatase (ALP biosensor has been developed. It is based on the detection of phenol produced by an ALP enzymatic reaction. It can operate at 25 °C in a pH 10 medium. It measures ALP of 0–300 IU/L. The permissible concentrations of glucose, ascorbic acid and urea without interference are 10 mM/L, 5 mg/L and 400 mg/L, respectively. Experimental results are compared to those obtained by spectrophotometric measurements in bovine serum. Excellent linearity between the biosensor outputs and the ALP concentrations exists. The agreement between the measurements of this biosensor and the spectrophotometer is also outstanding.

  14. Alkaline protease production from industrial wastes by bacillus subtilis ML-4

    International Nuclear Information System (INIS)

    The influence of various culture conditions on protease production by Bacillus subtilis ML-4 was studied in the presence of growth medium containing poultry feed waste (5%), K/sub 2/HPO/sub 4/ (0.3%), CaCl/sub 2/ (0.03%) and MgSO/sub 4/ (0.015%). Maximum protease production (264.25 +- 1.86 U/ml) was observed at initial pH 9 with 3% (v/v) of inoculum size after 48 h of incubation at 37 degree C. The alkaline protease was stable over a broad range of temperature (30 to 60 degree C) and pH (8 to 11). However, maximum activity (155.45 U/ml) was observed at temperature 50 degree C and pH 10. (author)

  15. Comparative study of polypyrrole films electrosynthesized in alkaline and acid solutions

    International Nuclear Information System (INIS)

    The influence of the pH of electropolymerization solutions on the properties of polypyrrole films has been studied using potentiodynamic techniques and faradaic impedance spectroscopy. Scanning electron microscopy (SEM), IR and Raman spectroscopies, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were also used for products characterization. Results indicate that, contrary to what happen with the polymer electrogenerated in acid solutions, the films prepared in alkaline media are stable and present good electrochemical activity in basic solutions. Possible explanations for the observed differences are discussed and it is proposed that the pH of electropolymerization medium directly affects chains organization. Electrosynthesis in solutions of increased basicity results in a more compact and closed polymer structure.

  16. A Constructed Alkaline Consortium and Its Dynamics in Treating Alkaline Black Liquor with Very High Pollution Load

    OpenAIRE

    Yang, Chunyu; Cao, Guangchun; Li, Yang; Zhang, Xiaojun; Ren, Hongyan; Wang, Xia; Feng, Jinhui; Zhao, Liping; Xu, Ping

    2008-01-01

    Background Paper pulp wastewater resulting from alkaline extraction of wheat straw, known as black liquor, is very difficult to be treated and causes serious environmental problems due to its high pH value and chemical oxygen demand (COD) pollution load. Lignin, semicellulose and cellulose are the main contributors to the high COD values in black liquor. Very few microorganisms can survive in such harsh environments of the alkaline wheat straw black liquor. A naturally developed microbial com...

  17. Amylase produced by Bacillus sp. SI-136 isolated from sodic-alkaline soil for efficient starch desizing

    OpenAIRE

    Sarethy, Indira P; Yashi Saxena; Aditi Kapoor; Manisha Sharma; Rohan Seth; Harsh Sharma; Sharma, Sanjeev K; Sanjay Gupta

    2012-01-01

    Bacillus sp. SI-136, isolated from sodic-alkaline soil, showed 94% similarity to B. cereus group based on 16S rDNA sequence. It produced α-amylase of 26 kDa with maximum activity at pH 10.0, stable up to pH 12.0 and 80oC. Mn2+ enhanced its activity as also 10% NaCl in medium. Agricultural waste substrates supported growth and enzyme activity was enhanced by 30% with sugarcane bagasse. The partially purified enzyme showed efficient desizing of cotton fabric at 50oC (40-60 min) or 70oC (...

  18. 21 CFR 862.1050 - Alkaline phosphatase or isoenzymes test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alkaline phosphatase or isoenzymes test system... Test Systems § 862.1050 Alkaline phosphatase or isoenzymes test system. (a) Identification. An alkaline phosphatase or isoenzymes test system is a device intended to measure alkaline phosphatase or its...

  19. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Science.gov (United States)

    2010-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... alkaline cleaning baths to remove mineral and animal fats or oils from the steel, and those...

  20. Kinetics and mechanism of oxidation of L-leucine by alkaline diperiodatocuprate(III)—A free radical intervention, deamination and decarboxylation

    Indian Academy of Sciences (India)

    Keerti M Naik; Sharanappa T Nandibewoor

    2012-07-01

    The kinetics of oxidation of L-leucine by diperiodatocuprate (III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.10mol dm-3 was studied spectrophotometrically. The reaction between L-leucine and DPC in alkaline medium exhibits 1:4 stoichiometry (L-leucine: DPC). The reaction is of first order in [DPC] and has less than unit order in both [L-leucine] and [alkali]. However, the order in [Lleucine] and [alkali] changes from first order to zero order as their concentration increase. Intervention of free radicals was observed in the reaction. Increase in periodate concentration decreased the rate. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate (III) - L-leucine complex, which decomposed slowly in a rate-determining step followed by other fast steps to give the products. The main oxidative products were identified by spot test and GC-MS. The reaction constants involved in the different steps of the mechanism were calculated.

  1. Evaluation of some bean lines tolerance to alkaline soil

    Directory of Open Access Journals (Sweden)

    Abeer A. Radi

    2012-01-01

    Full Text Available Introduction: In less arid climates, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. The development and identification of salt-tolerant crop cultivars or lines would complement salt management programs to improve the productivity and yields of salt stressed plants.Materials and methods: This work was to study the evaluation of alkalinity tolerance of some bean lines grown under different levels of sodium carbonate (Na2CO3 to select the most alkalinity tolerant lines versus the most-sensitive ones out of 6 lines of the test plants.Results: The symptoms induced by alkalinity included reduction in root, shoot growth, and leaf area which were more severe in some bean lines. Potassium leakage was severely affected by alkalinity in some lines at all tested levels, while in some others a moderate damage was manifested only at the higher levels. The increase in Na2CO3 level was associated with a gradual fall in chlorophyll a and b biosynthesis of all the test bean lines. However, alkalinity at low and moderate levels had a favorable effect on the biosynthesis of carotenoids in all the test bean lines. The increase in Na2CO3 supply had a considerable stimulatory effect on sodium accumulation, while potassium accumulation fluctuated in organs of bean lines.Conclusion: Assiut 1104 out of all the different lines investigated was found to display the lowest sensitivity to alkalinity stress, while Assiut 12/104 was the most sensitive one.

  2. Serum alkaline phosphatase screening for vitamin D deficiency states

    International Nuclear Information System (INIS)

    Objective: To determine whether serum vitamin D levels are correlated with serum levels of alkaline phosphatase or not. Study Design: Cross-sectional, observational study. Place and Duration of Study: Multi-centre study, conducted at Liaquat National Hospital and Medical College, National Medical Centre and Medicare Hospital, Karachi, from January to October 2009. Methodology: Patients attending the Orthopaedic OPDs with complaints of pain in different body regions and serum vitamin D/sub 3/ levels of greater or equal to 30 ng/ml were included in the study. Patients with vitamin D deficiency were further categorized into mild deficiency or insufficiency (vit. D/sub 3/ = 20-29 ng/ml), moderate deficiency (vit. D/sub 3/ = 5 - 19 ng/ml) and severe deficiency forms (vit. D/sub 3/ < 5 ng/ml). Pearson correlation was applied to test the correlation of serum alkaline phosphatase levels with serum vitamin D/sub 3/ levels. P-value < 0.05 was considered to be significant. Results: Out of 110 samples, 26 had mild (23%), 61 had moderate (55%) and 21 had severe (19.1%) vitamin D deficiencies. All of the patients in the three groups had alkaline phosphatase with in normal limits and the total mean value of the enzyme was 135.97 +- 68.14I U/L. The inter group comparison showed highest values of alkaline phosphatase in the moderate vitamin D deficiency group. The correlation coefficient of alkaline phosphatase and serum vitamin D/sub 3/ levels was r =0.05 (p =0.593). Conclusion: Serum vitamin D/sub 3/ levels may not be correlated with increased serum alkaline phosphatase levels. Therefore, alkaline phosphatase may not be used as a screening test to rule out vitamin D deficiency. (author)

  3. 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.

  4. Quantum tunneling in thermal medium

    OpenAIRE

    Matsumoto, Sh.; Yoshimura, M.

    2000-01-01

    Time evolution of tunneling phenomena in medium is studied using a standard model of environment interaction. A semiclassical formula valid at low, but finite temperatures is derived in the form of integral transform for the reduced Wigner function, and the tunneling probability in thermal medium is calculated for a general tunneling potential of one dimensional system. Effect of dissipation, its time evolution in particular, depends on the behavior of the potential far beyond the barrier.

  5. Properties of the nuclear medium

    OpenAIRE

    M. BaldoINFN sezione di Catania, Italy; Burgio, G.F.

    2011-01-01

    We review our knowledge on the properties of the nuclear medium that have been studied, along many years, on the basis of many-body theory, laboratory experiments and astrophysical observations. First we consider the realm of phenomenological laboratory data and astrophysical observations, and the hints they can give on the characteristics that the nuclear medium should possess. The analysis is based on phenomenological models, that however have a strong basis on physical in...

  6. Production and Characterization of Alkaline Protease from a High Yielding and Moderately Halophilic Strain of SD11 Marine Bacteria

    Directory of Open Access Journals (Sweden)

    Hongxia Cui

    2015-01-01

    Full Text Available A marine bacterium SD11, which was isolated from sea muds (Geziwo Qinhuangdao Sea area, China, was used to produce thermostable alkaline serine nonmetal protease in the skim milk agar plate medium with 10% NaCl. The optimal temperature about the manufacture of the extracellular protease was ~60°C. The crude enzyme was stable at 20–50°C. The activity was retained to 60% and 45% after heating for 1 h at 60 and 70°C, respectively. The protease was highly active in a wide pH scope (8.0–10.0 and maximum protease activity exhibited at pH 10.0. The activity was restrained by phenylmethylsulfonyl fluoride (PMSF but mildly increased (~107% in the presence of ethylenediaminetetraacetic acid (EDTA, indicating that the production contains serine-protease(s and nonmetal protease(s. Moreover, the crude alkaline protease was active with the 5 mM Ca2+, Mn2+, Zn2+, Cu2+, Na+, and K+ that existed separately. In addition, the protease showed superduper stability when exposed to an anionic surfactant (5 mM SDS, an oxidizing agent (1% H2O2, and several organic solvents (methanol, isopropanol, and acetone. These results suggest that the marine bacterium SD11 is significant in the industry from the prospects of its ability to produce thermally stable alkaline protease.

  7. ADVANCES IN THE MODEL OF CYLINDRICAL ALKALINE CELLS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The advancement of a systematic investigation on the modeling of cylindrical alkaline cells is presented.Initial analysis utilizes thermodynamic and kinetic information to predict alkaline cell performance under low discharge rates.Subsequent modling has taken into consideration detailed information on the chemistry of electrode reactions,mass tranport of dissolved species,physical and chemical properties of the electrolyte and solid phases,and internal geonetry of cell systems.The model is capable of predicting alkaline cell performance under a variety of dicharge conditions.The model also provides information regarding internal cell changes during discharge.The model is the basis of a rational approach for the optimal design of cells.

  8. POLYETHER POLYURETHANE FROM MODIFIED WHEAT STRAW OXYGEN-ALKALINE LIGNIN

    Institute of Scientific and Technical Information of China (English)

    Quanxiao Liu; Huaiyu Zhan; Beihai He; Shuhui Yang; Jianhua Liu; Jianlu Liu; Zhenxing Pang

    2004-01-01

    Polyether polyurethane was synthesized from modified wheat straw oxygen-alkaline lignin,polyethylene glycol and two different diisocyanates (diphenylemethane-4, 4′-diisocyanate, tolulene diisocyanate) by solution casting method, its properties were investigated. The results show that modified wheat straw oxygen-alkaline lignin can substitute part of polyethylene glycol to react with diisocyanate to synthesize polyurethane. The molar ratio of NCO to OH and modified wheat straw oxygen-alkaline lignin content affect the properties of lignin-based polyether polyurethane respectively. The addition of plasticizer in the polyurethane synthesis process improves the properties of synthesized polyurethane, especially the elasticity of polyurethane. The synthesized polyurethane from modified wheat straw oxygen-alkali lignin can be used as both engineering plastic and hard foam plastic in future.

  9. POLYETHER POLYURETHANE FROM MODIFIED WHEAT STRAW OXYGEN-ALKALINE LIGNIN

    Institute of Scientific and Technical Information of China (English)

    QuanxiaoLiu; HuaiyuZhan; BeihaiHe; ShuhuiYang; JianhuaLiu; JianluLiu(1); ZhenxingPang

    2004-01-01

    Polyether polyurethane was synthesized from modified wheat straw oxygen-alkaline lignin, polyethylene glycol and two different diisocyanates (diphenylemethane-4, 4'-diisocyanate, tolulene diisocyanate) by solution casting method, its properties were investigated. The results show that modified wheat straw oxygen-alkaline lignin can substitute part of polyethylene glycol to react with diisocyanate to synthesize polyurethane. The molar ratio of NCO to OH and modified wheat straw oxygen-alkaline lignin content affect the properties of lignin-based polyether polyurethane respectively. The addition of plasticizer in the polyurethane synthesis process improves the properties of synthesized polyurethane, especially the elasticity of polyurethane. The synthesized polyurethane from modified wheat straw oxygen-alkali lignin can be used as both engineering plastic and hard foam plastic in future.

  10. Transient species produced in irradiated alkaline aqueous solutions containing oxygen

    International Nuclear Information System (INIS)

    The spectra and decay kinetics of the optical absorption in the UV region and at 430nm (maximum of the ozonide ion absorption), were investigated in oxygenated neutral, slightly and strongly alkaline aqueous solutions. It is assumed that the initial absorption after the pulse in oxygenated alkaline solutions is due to the ozonide ion O3-, superoxide radical ion O2- and ozone O3. The long-living absorption in these solutions cannot be excluded as to be probably caused by the ozone O3 or some product formed from O2- or an alkaline stabilized form of this radical-ion. The advantage of applying additional non-optical measurements of the system is shown on the example of H2O2 role played in the mechanism. (author)

  11. Alkaline direct alcohol fuel cells using an anion exchange membrane

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Koji; Iriyama, Yasutoshi; Abe, Takeshi; Ogumi, Zempachi [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Matsuoka, Masao [Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan)

    2005-10-04

    Alkaline direct alcohol fuel cells using an OH-form anion exchange membrane and polyhydric alcohols were studied. A high open circuit voltage of ca. 800mV was obtained for a cell using Pt-Ru/C (anode) and Pt/C (cathode) at 323K, which was about 100-200mV higher than that for a DMFC using Nafion{sup R}. The maximum power densities were in the order of ethylene glycol>glycerol>methanol>erythritol>xylitol. Silver catalysts were used as a cathode catalyst to fabricate alkaline fuel cells, since silver catalyst is almost inactive in the oxidation of polyhydric alcohols. Alkaline direct ethylene glycol fuel cells using silver as a cathode catalyst gave excellent performance because higher concentrations of fuel could be supplied to the anode. (author)

  12. Geology and petrology of Lages Alkaline District, Santa Catarina State

    International Nuclear Information System (INIS)

    A 1:100.000 geological map shows the main outcrops, covering about 50 Km2, of the leucocratic alkaline rocks, ultra basic alkaline rocks, carbonatites and volcanic breccias which intruded the Gondwanic sedimentary rocks within a short time interval and characterize the Alkaline District of Lages. Chemical analyses of 33 whole-rock samples confirm the petrographic classification, but the agpaitic indexes, mostly below 1.0, do not reflect the mineralogical variations of the leucocratic alkaline rocks adequately. Partial REE analyses indicate that the light as well as the heavy rare earth contents decrease from the basic to the more evolved rocks, the La/Y ratio remaining approximately constant. Eleven new K/Ar ages from porphyritic nepheline syenites porphyritic phonolites, ultra basic alkaline rocks and pipe-breccias, together with six already available ages, show a major concentration in the range 65 to 75 Ma, with a mode at ca. 70 Ma. But one Rb/Sr whole-rock reference isochron diagram gives an age of 82+-6 Ma for the agpaitic phonolites of the Serra Chapada, which are considered younger than the miaskitic porphyriric nepheline syenites. The 87 Sr/86 Sr ratios of 0.705-0.706 are compatible with a sub continental mantelic origin, devoid of crustal contamination. A petrogenetic model based on subtraction diagrams and taking into consideration the geologic, petrographic, mineralogic and petrochemical characteristics of the alkaline rocks of Lages consists of limited partial melting with CO2, contribution of the previously metasomatized upper mantle, in a region submitted to decompression. (author)

  13. Effectiveness of the squeezing out and final squeezing out of petroleum of an increased viscosity by alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Begnazarov, T.

    1979-01-01

    The remaining petroleum in the flooded zone is determined by the ratio of viscosity forces to the forces of the surface tension, which are expressed by the coefficient Ka. With this, for each kind of porous medium, there exists a natural cricial value Ka. For the purpose of studying the effect of the given parameters on the value of the remaining petroleum, experiments were carried out on artificial specimens. In the tests, using petroleum of the Mishkin deposit, the surface tension on the boundary of the petroleum with the distilled water and alkaline solutions were respectively equal to 37.1 and 1.33 dynes per centimeter. The experiments showed, that the squeezing out of the petroleum with water or alkaline solutions leads to similar results. This means, that the composite parameter Ka does not affect the value of the remaining petroleum saturation. The effectiveness of the final squeezing out of the petroleum of increased viscosity was also studied. These experiments were carried out in two variations of the injection of the squeezed out agent: in the first variation, the petroleum was squeezed out with water in the first stage, and in the second stage it was squeezed out by an alkaline solution, and in the subsequent stages, a change in the squeezing out agent took place. By finishing the first stage, the attained values of the coefficients of the squeezing out were practically similar (0.72). In the second stage, the final squeezing out of the petroleum with a solution of alkaline, provided a major effect.

  14. Medium-assisted vacuum force

    CERN Document Server

    Tomas, M S

    2005-01-01

    We discuss some implications of a very recently obtained result for the force on a slab in a planar cavity based on the calculation of the vacuum Lorentz force [C. Raabe and D.-G. Welsch, Phys. Rev. A 71, 013814 (2005)]. We demonstrate that, according to this formula, the total force on the slab consists of a medium-screened Casimir force and, in addition to it, a medium-assisted force. The sign of of the medium-assisted force is determined solely by the properties of the cavity mirrors. In the Lifshitz configuration, this force is proportional to 1/d at small distances and is very small compared with the corresponding van der Waals force. At large distances, however, it is proportional to 1/d^4 and is comparable with the Casimir force, especially for denser media. The exponents in these power laws decrease by 1 in the case of a thin slab. The formula for the medium-assisted force also describes the force on a layer of the cavity medium, which has similar properties. For dilute media, it implies an atom-mirro...

  15. Direct Promotion of Collagen Calcification by Alkaline Phosphatase

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Alkaline phosphatase promotes hydrolysis of phosphate containing substrates, causes a rise in inorganic phosphate and, therefore, enhances calcification of biological tissues. In this work, the calcification of collagen in a model serum was used as a model of collagenous tissue biomaterials to study the possible calcification promotion mechanism of alkaline phosphatase. In the enzyme concentration range of 0.10.5mg/mL, the enzyme shows a direct calcification promoting effect which is independent of the hydrolysis of its phosphate containing substrates but proportional to the enzyme concentration. Potassium pyrophosphate somewhat inhibits the calcification promotion.

  16. Plasma acid and alkaline phosphatase in patients with breast cancer.

    Science.gov (United States)

    Nguyen, M; Bonneterre, J; Hecquet, B; Desoize, B; Demaille, A

    1991-01-01

    Acid and alkaline phosphatase were determined in 107 breast cancer patients to study their potential value in case of bone metastases. The patients were divided into 4 groups: A, patients without metastases (n = 34); B, metastatic patients without bone lesions (n = 37); C, patients with metastases in and outside of bones (n = 24), D, patients with bone-only metastases (n = 12). Tartrate resistant acid phosphatase (TR-ACP), and bone alkaline phosphatase (bone-ALP) were significantly higher in patients with metastases than in patients without. However, no difference in TR-ACP was observed between subgroups of metastatic patients. PMID:2064338

  17. Alkaline solution absorption of carbon dioxide method and apparatus

    Science.gov (United States)

    Hobbs, D.T.

    1991-01-01

    Disclosed is a method for measuring the concentration of hydroxides (or pH) in alkaline solutions, using the tendency of hydroxides to adsorb CO{sub 2}. The method comprises passing CO{sub 2} over the surface of an alkaline solution in a remote tank before and after measurements of the CO{sub 2} concentration. Comparison of the measurements yields the adsorption fraction from which the hydroxide concentration can be calculated using a correlation of hydroxide or pH to adsorption fraction. A schematic is given of a process system according to a preferred embodiment of the invention. 2 figs.

  18. Effect of alkaline treatment on the ultrastructure of starch granules

    International Nuclear Information System (INIS)

    Starch is a plant polysaccharide that occurs as discrete and partially crystalline microscopic granules. The development of different extraction methods to isolate granules with high purity and well-defined physical properties has increased due to the wide utilization of starch as an ingredient in the food industry. Alternatives to the pattern alkaline extraction protocol have been investigated in order to improve the extraction yield while maintaining the functional properties of the starch granules. In this work, we focused our efforts on the evaluation of the effect of alkaline treatments on the ultrastructure of Araucaria angustifolia (pinhao) starch granules during their extraction. (author)

  19. Suitability of Sudanese Cotton Stalks for Alkaline Pulping with Additives

    Directory of Open Access Journals (Sweden)

    Tarig Osman Khider

    2012-01-01

    Full Text Available The fibre characteristics and chemical composition of Gossypium Hirsutum, Sudanese cotton stalks were assessed for their suitability for papermaking. Soda-anthraquinone (soda-AQ, alkaline sulphite-anthraquinone (AS-AQ and ASAM (alkaline sulphite-anthraquinone- methanol cookings were carried out with different alkali charges and pulps with acceptable to good yields and mechanical properties were obtained. ASAM pulping gave the best results in yields, degree of delignification, mechanical pulp properties. AS-AQ pulping cooking with ratio (70: 30 as NaOH: Na2SO3 gave better results compared to (60: 40 ratio.

  20. Zeolites as structure formation products of alkalineous cements hydration

    OpenAIRE

    Kryvenko, Р. V.; Runova, R. F.; Rudenko, I. I.

    2014-01-01

    The paper concerns analysis of theoretical and experimental studies, according to which, in conditions of artificial stone making for buildings purposes (cement, concrete), synthesis of alkaline aluminosilicates similar to natural minerals of zeolitic group occurs. Presence of such new formations in hydration products of standartized type alkaline cements provides their high running abilities and durability. Наведено аналіз теоретичних і експериментальних досл...

  1. Research on Alkaline Filler Flame-Retarded Asphalt Pavement

    Institute of Scientific and Technical Information of China (English)

    HU Shuguang; ZHANG Houji; WANG Jiaolan

    2006-01-01

    Used as flame retardant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, and the flame-retarded asphalt mixtures were produced. Experimental results show that these asphalt mixtures are smoke restrained; the performances and construction technology of asphalt pavement are not influenced; also the alkaline filler is of low-price. So this kind of flame-retarded asphalt mixtures is suitable for tunnel pavement.

  2. Surface-treatment of Alkaline Earth Sulfides Based Phosphor

    Institute of Scientific and Technical Information of China (English)

    GUO Chong-feng; CHU Ben-li; XU Jian; SU Qiang

    2004-01-01

    A series of alkaline earth sulfides based phosphors Ca0.8Sr0.2S∶Eu2+, Tm3+ were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH4HF2 at elevated temperatures. The coatings were characterized by means of XRD and SEM. The optical properties of the coated phosphors and the influences of the coating on their properties have been discussed extensively. The stabilities of the coated and uncoated phosphors have been compared.

  3. Recovery of manganese oxides from spent alkaline and zinc-carbon batteries. An application as catalysts for VOCs elimination.

    Science.gov (United States)

    Gallegos, María V; Falco, Lorena R; Peluso, Miguel A; Sambeth, Jorge E; Thomas, Horacio J

    2013-06-01

    Manganese, in the form of oxide, was recovered from spent alkaline and zinc-carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO4 solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnOx synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn2O3 in the EMO and the CMO samples, together with some Mn(4+) cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn3O4. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200°C, while heptane requires more than 400°C. The CMO has the highest oxide selectivity to CO2. The results show that manganese oxides obtained using spent alkaline and zinc-carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs. PMID:23562448

  4. Study on Effect and Catalytic Mechanism of the Catalysts for Coal Oxidation in Alkaline Medium%Study on Effect and Catalytic Mechanism of the Catalysts for Coal Oxidation in Alkaline Medium

    Institute of Scientific and Technical Information of China (English)

    刘怀有; 吕经康; 赵永刚; 周尉; 印仁和

    2011-01-01

    Coal electro-oxidation in sodium hydroxide solution with catalysts, K3Fe(CN)6, sodium hypochlorite and sup- ported FeS, were investigated, respectively. Gas produced from electro-analysis of coal slurry was collected by drainage-method and l-t curves were recorded to testify the catalysis of each catalyst for coal oxidation. The results show that the three kinds of catalysts can obviously improve the coal oxidation current. Furthermore, K3Fe(CN)6 and sodium hypochlorite played an indirect oxidation role in the electrolysis process. Catalysts bridge the coal par- ticles and the solid electrode surface, thus increase the coal oxidation rates. The changes of catalyst content during the electrolysis were further determined by quantitative titration to discuss the catalytic Mechanism. The dynamic transition of K3Fe(CN)6/K4Fe(CN)6 and ClO^-/Cl^- are proposed by iodometric method.

  5. Recovery of manganese oxides from spent alkaline and zinc–carbon batteries. An application as catalysts for VOCs elimination

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos, María V., E-mail: plapimu@yahoo.com.ar [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina); Falco, Lorena R., E-mail: mlfalco@quimica.unlp.edu.ar [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina); Peluso, Miguel A., E-mail: apelu@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas, “Dr. J. Ronco” CINDECA (CONICET CCT La Plata), 47 N°257, La Plata, Buenos Aires (Argentina); Sambeth, Jorge E., E-mail: sambeth@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas, “Dr. J. Ronco” CINDECA (CONICET CCT La Plata), 47 N°257, La Plata, Buenos Aires (Argentina); Thomas, Horacio J. [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina)

    2013-06-15

    Highlights: • Manganese oxides were synthesized using spent batteries as raw materials. • Spent alkaline and zinc–carbon size AA batteries were used. • A biohydrometallurgical process was employed to bio-lixiviate batteries. • Manganese oxides were active in the oxidation of VOCs (ethanol and heptane). - Abstract: Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO{sub 4} solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnO{sub x} synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn{sub 2}O{sub 3} in the EMO and the CMO samples, together with some Mn{sup 4+} cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn{sub 3}O{sub 4}. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200 °C, while heptane requires more than 400 °C. The CMO has the highest oxide selectivity to CO{sub 2}. The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs.

  6. Recovery of manganese oxides from spent alkaline and zinc–carbon batteries. An application as catalysts for VOCs elimination

    International Nuclear Information System (INIS)

    Highlights: • Manganese oxides were synthesized using spent batteries as raw materials. • Spent alkaline and zinc–carbon size AA batteries were used. • A biohydrometallurgical process was employed to bio-lixiviate batteries. • Manganese oxides were active in the oxidation of VOCs (ethanol and heptane). - Abstract: Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO4 solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnOx synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn2O3 in the EMO and the CMO samples, together with some Mn4+ cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn3O4. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200 °C, while heptane requires more than 400 °C. The CMO has the highest oxide selectivity to CO2. The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs

  7. Properties of the nuclear medium

    International Nuclear Information System (INIS)

    We review our knowledge on the properties of the nuclear medium that have been studied, over many years, on the basis of many-body theory, laboratory experiments and astrophysical observations. Throughout the presentation particular emphasis is placed on the possible relationship and links between the nuclear medium and the structure of nuclei, including the limitations of such an approach. First we consider the realm of phenomenological laboratory data and astrophysical observations and the hints they can give on the characteristics that the nuclear medium should possess. The analysis is based on phenomenological models, that however have a strong basis on physical intuition and an impressive success. More microscopic models are also considered, and it is shown that they are able to give invaluable information on the nuclear medium, in particular on its equation of state. The interplay between laboratory experiments and astrophysical observations is particularly stressed, and it is shown how their complementarity enormously enriches our insights into the structure of the nuclear medium. We then introduce the nucleon–nucleon interaction and the microscopic many-body theory of nuclear matter, with a critical discussion about the different approaches and their results. The Landau–Fermi liquid theory is introduced and briefly discussed, and it is shown how fruitful it can be in discussing the macroscopic and low-energy properties of the nuclear medium. As an illustrative example, we discuss neutron matter at very low density, and it is shown how it can be treated within the many-body theory. The general bulk properties of the nuclear medium are reviewed to indicate at which stage of our knowledge we stand, taking into account the most recent developments both in theory and experiments. A section is dedicated to the pairing problem. The connection with nuclear structure is then discussed, on the basis of the energy density functional method. The possibility of

  8. Pions in the nuclear medium

    CERN Document Server

    de Melo, J P B C; El-Bennich, Bruno; Rojas, E; Frederico, T

    2014-01-01

    Using the light-front pion wave function based on a Bethe-Salpeter amplitude model, we study the properties of the pion in symmetric nuclear matter. The pion model we adopt is well constrained by previous studies to explain the pion properties in vacuum. In order to consistently incorporate the constituent up and down quarks of the pion immersed in symmetric nuclear matter, we use the quark-meson coupling model, which has been widely applied to various hadronic and nuclear phenomena in a nuclear medium with success. We predict the in-medium modifications of the pion lectromagnetic form factor, charge radius and weak decay constant in symmetric nuclear matter.

  9. Soil alkalinization and irrigation in the sahelian zone of Niger : 2. Agronomic consequences of alkalinity and sodicity

    OpenAIRE

    Marlet, S.; Barbiéro, Laurent; Valles, V.

    1998-01-01

    Soils of the terraces of the Niger River have locally undergone, prior to irrigation, a process of alkalinization. The use of the resulting nonsaline sodic soils [pHs 8.5-9.8 (s is "on saturated paste"), ECs = 2.2-3.2 dS/m, SAR = 12-28 (mmol/L)(at the power 1/2), exchangeable sodium percentage (ESP) = 5-40] is greatly limited because of their alkalinity and sodicity. The mechanisms of degradation affecting the soil physicochemical properties, the water supply, and the mineral nutrition of cro...

  10. Fabrication of a novel PtPbBi/C catalyst for ethanol electro-oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Highlights: ► Pb atoms were imbedded into Pt lattice by the microwave action. ► PtPb/C surface was modified by Bi via an irreversible chemisorption approach. ► Addition of both Pb and Bi facilitates the formation of oxygenated species. ► The ethanol oxidation current on PtPbBi/C is 4.1 times higher than that on Pt/C. ► Ethanol dehydrogenation and removal of CO-like species on PtPbBi/C are greatly enhanced. - Abstract: This work presents a general strategy to fabricate a new type of ternary intermetallic PtPbBi/C nano-catalyst. X-ray diffraction, transmission electron microscope and X-ray photoelectron spectroscopy data demonstrate that some Pb atoms are imbedded into Pt lattice to form PtPb alloy particles in the microwave action. The PtPb/C catalyst surface is further modified by Bi via a spontaneous and irreversible chemisorption approach. Ethanol oxidation peak current on PtPbBi/C (217.9 mA cm−2) is about 4.1 times higher than that on Pt/C (53.6 mA cm−2) in cyclic voltammograms. Tafel plots show that both ethanol dehydrogenation and removal of CO-like species are greatly enhanced on the novel PtPbBi/C catalyst. Constant potential and linear current sweep tests indicate that the addition of Pb and Bi causes the formation of abundant oxygenated species on the catalyst surface at low potential. These oxygenated species can react with poisonous intermediates formed during ethanol oxidation, and help the release of free Pt active sites for further adsorption and electro-oxidation of ethanol molecules.

  11. Nitrogen-doped graphene supported highly dispersed palladium-lead nanoparticles for synergetic enhancement of ethanol electrooxidation in alkaline medium

    International Nuclear Information System (INIS)

    Highlights: • A novel N-doped graphene supported PdPb nanocatalyst was prepared. • N-doped graphene facilitates more uniform dispersion of metal particles than graphene. • Current for ethanol oxidation of PdPb/NG (152.3 mA cm−2) is 4 times higher than Pd/G. • PdPb/NG catalyst shows excellent catalytic durability among the catalysts. • Catalytic performance was enhanced by the bifunctional mechanism and electronic effect. - Abstract: In this work, a series of palladium and palladium-lead nanoparticles supported on active carbon, graphene and nitrogen-doped graphene are synthesized via a one-step reduction method. Atomic absorption spectroscopy, X-ray powder diffraction, transmission electron microscope and X-ray photoelectron spectroscopy are used to characterize the catalysts. The results indicate that metal nanoparticles are more uniformly dispersed on the surface of N-doped graphene than those on graphene, without any aggregation. Various electrochemical techniques are carried out to evaluate the electrocatalytic ethanol oxidation activity and durability. The peak current for ethanol electrooxidation of Pd/N-doped graphene increases to 70.2 mA cm−2, obviously higher than that of Pd/Graphene (38.0 mA cm−2) and even surpasses that of Pd/C (51.9 mA cm−2). N-doped graphene support not only possesses faster dehydrogenation but provides an electron effect to Pd. Introduction of Pb into the catalyst causes the formation of abundant oxygenated species on the catalyst surface at low potential. Based on the synergistic effect of N and Pb towards Pd particles, the PdPb/N-doped graphene catalyst (Pd:Pb = 8:1.0) exhibits remarkably enhanced activity up to 152.3 mA cm−2 for ethanol oxidation, which is 4.0 and 2.9 times higher than that of Pd/Graphene and Pd/C, respectively. The catalytic durability and stability are also greatly improved

  12. Bi-modified Pd/C catalyst via irreversible adsorption and its catalytic activity for ethanol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Highlights: • Pd-Bi/C catalysts were easily prepared by irreversible adsorption of Bi on Pd/C surface. • The adsorption of Bi increases the oxygen-containing species obviously on Pd-Bi/C surface. • Only a little amount of Bi on Pd-Bi/C can play a significant role in ethanol oxidation reaction (EOR). • Current density of EOR on Pd-Bi/C (20:1) is 2.4 times higher than that on Pd/C. • Anti-poisoning ability and durability of Pd-Bi/C (20:1) is greatly enhanced. -- Abstract: A facile approach to promote ethanol electro-oxidation on Pd-based catalysts is presented by the modification of Bi on Pd/C catalyst via irreversible adsorption. X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) measurements show that the modification of Bi has no significant effect on the Pd morphology and particle size distribution. Bi(III) and Pd(0) are the dominant forms in Pd-Bi/C catalyst. Electrochemical tests show that the modification of the appropriate amount of Bi on Pd/C catalyst can remarkably enhance activity toward ethanol oxidation reaction (EOR) up to about 2.4 times higher compared to Pd/C catalyst. The Pd-Bi/C (20:1) catalyst exhibits excellent stability and enhances CO tolerance. The enhanced electrochemical performance of Pd-Bi/C catalyst is attributed to the electronic effect and the bifunctional mechanism. The high exchange current density and the low apparent activation energy on Pd-Bi/C (20:1) catalyst reveal its faster kinetics and higher intrinsic activity compared to Pd/C catalyst

  13. Pt- and Ru-Doped SnO2–Sb Anodes with High Stability in Alkaline Medium

    OpenAIRE

    Berenguer Betrián, Raúl; Sieben, Juan Manuel; Quijada Tomás, César; Morallón Núñez, Emilia

    2014-01-01

    Different Pt- and Ru-doped Ti/SnO2–Sb electrodes were synthesized by thermal decomposition. The effect of the gradual substitution of Sb by Ru in the nominal composition on the physicochemical and electrochemical properties were evaluated. The electrochemical stability of the electrodes was estimated from accelerated tests at 0.5 A cm–2 in 1 M NaOH. Both as-synthesized and deactivated electrodes were thoroughly characterized by scanning electron microscopy (SEM), energy-dispersive X-ray micro...

  14. MnxCu1-xCo2O4 used as bifunctional electrocatalyst in alkaline medium

    International Nuclear Information System (INIS)

    Composite film electrodes containing mechanically mixed MnxCu1-xCo2O4 (0 ≤ x ≤ 1) particles, carbon black Vulcan XC72R and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) were formed on the glassy carbon disk surface of a rotating ring-disk electrode (RRDE) and studied for the oxygen reduction and evolution reactions (ORR and OER, respectively) in 1 M KOH solution. The electrocatalytic activities for both reactions were observed to depend strongly on the Mn content in CuCo2O4. An opposite trend was observed for the apparent and intrinsic electrocatalytic activities for the ORR; the simultaneous presence of Cu and Mn was found to be detrimental to the intrinsic charge density, but beneficial to the geometric charge density with a maximum for Mn0.6Cu0.4Co2O4. The latter was characterized by the highest total number of electrons exchanged per O2 molecule, n, close to 4, greater k1 (4e- process)/k2 (2e- process) ratios, and by a unique and low Tafel slope (-41 mV dec-1). The results obtained for the OER showed that the intrinsic electrocatalytic activity is determined by the number of active sites (Co4+) electrochemically formed at the oxide surface prior to the OER, from Co3+ cations. The partial substitution of Cu by Mn in CuCo2O4 was found to decrease the OER activity

  15. Poly(L-lactic acid scaffold: in vitro degradation in alkaline medium, phosphate buffer solution and osteoblast morphology

    Directory of Open Access Journals (Sweden)

    Samuel Hilsdorf Barbanti

    2006-01-01

    Full Text Available Poli(L-ácido láctico (PLAL es un biodegradable y bioreabsorbible polímero ampliamente estudiado para las aplicaciones biomédicas como una alternativa para el tratamiento de lesiones y la pérdida de tejido. Como biomaterial temporal, la degradación del PLAL ocurre por la hidrólisis. Los productos de degradaci ón (dióxido del carbono y agua son metabolizados por el organismo. El objetivo de este trabajo fue obtener, caracterizar y evaluar la degradación in vitro de membranas de PLAL densas y porosas. Las membranas densas fueran preparadas por la disolucion del polímero en cloroformo 10 % (m/v, a temperatura ambiente. La disolución fue transferida a una placa de vidrio para secarla. Lás membranas porosas se prepararon de forma similar a la previamente descrita. El citrato de sodio fue incluido [50 % (m/v] con diámetro de grano < 45 mm, 180 a 250 mm y 250 a 350 mm . Después de secada, la membrana se sumergió en agua destilada. Membranas de masas molares diferentes (Mw = 300 000 y 100 000 fueron estudiadas por Microscopia Electrónica (ME y Calorimetría Diferencial de Barrido. El efecto del medio de degradación [disolución reguladora de fosfato (PBS y alcalina (NaOH] también fue estudiado. La cultura de los osteoblastos se evaluó por ME. Los resultados permitirón concluir que el medio alcalino acelera significativamente el proceso de degradación del PLAL, observando un efecto mayor en las estructuras densas. La morfología del proceso de degradación confirma los efectos auto-catalizadores de los poli(alfa-hidroxiácidos en que la degradación se acentúa más en las estructuras densas debido a la concentración de los productos ácidos dentro del material. Los datos de cultura de los osteoblastos mostraron una morfología semejante al control. Las membranas de PLAL pueden ser usadas en los casos donde la lesión exija un material con prolongado tiempo de degradaci ón, sirviendo como apoyo físico para las células y mecánico para el tejido.

  16. Degradation of Poly(L-Lactic Acid) and Bio-Composites by Alkaline Medium under Various Temperatures

    Science.gov (United States)

    Ribbons of poly(lactic acid) (PLA) and PLA containing 10 or 25 % Osage orange (OO) biocomposites of various sized heartwood particles were exposed to non-composting soil conditions either outdoors or in a greenhouse. No appreciable degradation was evident even after 208 day treatments. An artifici...

  17. Utilization of white rot fungi for textile dye decolourisation under alkaline condition and high salt concentration in solid medium

    OpenAIRE

    Ottoni, C. A.; Santos, Cledir; Lima, Nelson

    2010-01-01

    A large amount of azo dyes are used for dyeing textiles. However, the dyes contaminate wastewaters and need to be treated. This is important because of the aesthetic, toxic and carcinogenic effects of the affected waters. Recently there has been an increase in interest in using white rot fungi (wrf) which degrade xenobiotic compounds including azo dyes. Wrf degrade lignin and others recalcitrant molecules using nonspecific extracellular enzymes. Four white rot fungi...

  18. On the variation of alkalinity during phytoplankton photosynthesis

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available The alkalinity of the organic constituents of marine phytoplankton and their participation in the total alkalinity (TA change of seawater during photosynthesis are carefully assessed. Quantification of the contribution of phytoplankton chlorophyll, proteins and phosphorus compounds to the hydrogen ion balance of seawater in terms of total inorganic nitrogen (∆[NT] = ∆[NH4 +] + ∆[N2] + ∆[NO2 –] + ∆[NO3 –] and total inorganic phosphorus (∆[PT] changes during photosynthesis yielded that the organic components of marine phytoplankton are alkaline by –0.06 × ∆[NT] – 0.49 × ∆[PT], and that the potential total alkalinity (TAP during photosynthesis is TAP = TA – [NH4 –] + 0.93 × [NO2 –] + [NO3 –] + 0.08 × [NT] + 0.23 × [PT] for unfiltered seawater samples and TAP = TA – [NH4 –] + 0.93 × [NO2 –] + [NO3 –] + 0.02 × [NT] + 0.26 × [PT] for filtered seawater samples. These equations correct the traditionally used expression TAP = TA + [NO3 –]. The TAP anomalies are produced, in order of increasing importance, by N2 fixation, DMSP production and CaCO3 fixation.

  19. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...

  20. Mixed alkaline earth effect in sodium aluminosilicate glasses

    DEFF Research Database (Denmark)

    Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Mauro, John C.;

    2013-01-01

    While the mixed alkali effect has received significant attention in the glass literature, the mixed alkaline earth effect has not been thoroughly studied. Here, we investigate the latter effect by partial substitution of magnesium for calcium in sodium aluminosilicate glasses. We use Raman and NMR...

  1. Process of treating cellulosic membrane and alkaline with membrane separator

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    The improvement of water-soluble cellulose ether membranes for use as separators in concentrated alkaline battery cells is discussed. The process of contacting membranes with an aqueous alkali solution of concentration less than that of the alkali solution to be used in the battery but above that at which the membrane is soluble is described.

  2. Triethanolaminelaurylsulfate as a collector for alkaline earth metal ions

    International Nuclear Information System (INIS)

    Basic features of flotation isolation of magnesium, calcium, strontium and barium ions, collected with the help of triethanolaminelaurylsulphate (TEALS) are described. The efficiency of the process depends on the nature of alkaline earth ions, on their concentration, on pH and temperature

  3. Soil salinity and alkalinity in the Great Konya Basin, Turkey

    NARCIS (Netherlands)

    Driessen, P.M.

    1970-01-01

    In the summers of 1964 to 1968 a study was made of soil salinity and alkalinity in the Great Konya Basin, under the auspices of the Konya Project, a research and training programme of the Department of Tropical Soil Science of the Agricultural University, Wageningen.The Great Konya Basin, some 300 k

  4. Modelling the crystallisation of alkaline earth boroaluminosilicate glass ceramics

    DEFF Research Database (Denmark)

    Svenson, Mouritz Nolsøe; Agersted, Karsten; Holm, Paul Martin

    2014-01-01

    To investigate the potential use of a thermochemical software package (FactSage 6.2), in the design of alkaline earth boroaluminosilicate glass ceramics, experimental and modelled results on four glass ceramics were compared. Initially large discrepancies were found. These are described and related...

  5. Novel alkaline polymer electrolyte for water electrolysis with enhanced conductivity

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Bouzek, B.; Paidar, M.; Schauer, Jan

    Praha : Process Engineering, 2010. s. 110-111. ISBN 978-80-02-02246-6. [International Congress of Chemical and Process Engineering CHISA 2010 /19./ and European Congress of Chemical Engineering ECCE-7 /7./. 28.08.2010-01.09.2010, Praha] Institutional research plan: CEZ:AV0Z40500505 Keywords : novel alkaline polymer * polyelectrolytes Subject RIV: CD - Macromolecular Chemistry

  6. Alkaline polymer electrolyte fuel cells: Principle, challenges, and recent progress

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polymer electrolyte membrane fuel cells (PEMFC) have been recognized as a significant power source in future energy systems based on hydrogen. The current PEMFC technology features the employment of acidic polymer electrolytes which, albeit superior to electrolyte solutions, have intrinsically limited the catalysts to noble metals, fundamentally preventing PEMFC from widespread deployment. An effective solution to this problem is to develop fuel cells based on alkaline polymer electrolytes (APEFC), which not only enable the use of non-precious metal catalysts but also avoid the carbonate-precipitate issue which has been troubling the conventional alkaline fuel cells (AFC). This feature article introduces the principle of APEFC, the challenges, and our research progress, and focuses on strategies for developing key materials, including high-performance alkaline polyelectrolytes and stable non-precious metal catalysts. For alkaline polymer electrolytes, high ionic conductivity and satisfactory mechanical property are difficult to be balanced, therefore polymer cross-linking is an ultimate strategy. For non-precious metal catalysts, it is urgent to improve the catalytic activity and stability. New materials, such as transition-metal complexes, nitrogen-doped carbon nanotubes, and metal carbides, would become applicable in APEFC.

  7. Solvent Extraction of Alkaline Earth Metals with Alkylphosphorus Acids

    Institute of Scientific and Technical Information of China (English)

    XUXin; ZHUTun

    2002-01-01

    Solvent extraction equiliria of four main alkaline earth metals (magnesium, calcium, strontium and barium) with di(2-ethylhexyl) phosphoric acid (DEHPA), 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester, di(2,4,4-tri-methylpentyl) phosphinic acid and IR spectra of the extracts have been studied. The selectivity order is dependent of the e/r value and hydration energy of the metal ions. The minor shift of the P→O in IR absorption of the alkaline earth metal extracts indicates that the interaction between the metal ions and P→O is much weaker for alkaline earth metals than for transitional metals. The distribution of the four alkaline earth elements between aqueous solutions and solutions of DEHPA and neutral organophosphorus compunds, tri-n-butyl phosphate (TBP) or tri-octyl phosphine oxide (TOPO) in kerosene have been determined at varying ratio of TBP or TOPO to DEHPA and the positive synergism is observed. The synergic effects is explained by using IR spectra of the loaded organic phase.

  8. A physiologic function for alkaline phosphatase : Endotoxin detoxification

    NARCIS (Netherlands)

    Poelstra, Klaas; Bakker, W.W; Klok, P.A; Hardonk, M.J; Meijer, D.K F

    1997-01-01

    Alkaline phosphatase (AP), a common enzyme present in many species including humans, has been studied extensively. Although the enzyme is routinely applied as a marker for liver function, its biologic relevance is poorly understood. The reason for this is obvious: the pH optimum of AP in vitro, as m

  9. Chemical aspects of coal liquefaction by oxygen in alkaline slurries

    Energy Technology Data Exchange (ETDEWEB)

    Andreozzi, R.; Caprio, V.; Insola, A.

    1988-03-01

    Coal liquefaction by oxygen in alkaline slurries is reviewed from the chemical point of view. Available information is considered in the light of questions relating to coal liquefaction. A lack of chemical knowledge in this area is noted, especially on model compounds. 72 refs.

  10. Qualitative aspects of the degradation of mitomycins in alkaline solution.

    Science.gov (United States)

    Beijnen, J H; den Hartigh, J; Underberg, W J

    1985-01-01

    The major degradation product in alkaline solution of mitomycin A, mitomycin C and porfiromycin is the corresponding 7-hydroxymitosane. The isolation and the physico-chemical and analytical properties of these compounds and their derivatized analogues are discussed. Data are presented on the degradation of mitomycin C at extremely high pH values. PMID:16867711

  11. Field screening of cowpea cultivars for alkaline soil tolerance

    Science.gov (United States)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  12. Yield performance of cowpea genotypes grown in alkaline soils

    Science.gov (United States)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  13. A green method of graphene preparation in an alkaline environment

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Henych, Jiří; Bludská, Jana; Ecorchard, Petra; Kormunda, M.

    2015-01-01

    Roč. 24, MAY (2015), s. 65-71. ISSN 1350-4177 R&D Projects: GA ČR(CZ) GA14-05146S Institutional support: RVO:61388980 Keywords : Alkaline environment * Exfoliation * Graphene * Ultrasound Subject RIV: CA - Inorganic Chemistry Impact factor: 4.321, year: 2014

  14. Fibre optic humidity sensor designed for highly alkaline environments

    OpenAIRE

    Bremer, K; Wollweber, M; Guenther, S.; Werner, G.; Sun, T.; Grattan, K. T.; Roth, B.

    2014-01-01

    This paper presents the design of a sensor packaging for a Fibre Bragg Grating (FBG) based fibre optic humidity sensor. The evaluation of the developed fibre optic sensor was performed under experimental conditions and verified its capability to withstand highly alkaline environments. Therefore, the sensor can be applied to monitor the concrete humidity level and thus to indicate the maintenance of concrete structures.

  15. The catalytic properties of alkaline phosphatases under various conditions

    Science.gov (United States)

    Atyaksheva, L. F.; Chukhrai, E. S.; Poltorak, O. M.

    2008-11-01

    A comparative study was performed to examine the catalytic properties of alkaline phosphatases from bacteria Escherichia coli and bovine and chicken intestines. The activity of enzyme dimers and tetramers was determined. The activity of the dimer was three or four times higher than that of the tetramer. The maximum activity and affinity for 4-nitrophenylphosphate was observed for the bacterial alkaline phosphatase ( K M = 1.7 × 10-5 M, V max = 1800 μmol/(min mg of protein) for dimers and V max = 420 μmol/(min mg of protein) for tetramers). The Michaelis constants were equal for two animal phosphatases in various buffer media (pH 8.5) ((3.5 ± 0.2) × 10-4 M). Five buffer systems were investigated: tris, carbonate, hepes, borate, and glycine buffers, and the lowest catalytic activity of alkaline phosphatases at equal pH was observed in the borate buffer (for enzyme from bovine intestine, V max = 80 μmol/(min mg of protein)). Cu2+ cations formed a complex with tris-(oxymethyl)-aminomethane ( tris-HCl buffer) and inhibited the intestine alkaline phosphatases by a noncompetitive mechanism.

  16. Potentiodynamic characteristics of cadmium and silver in alkaline solutions

    International Nuclear Information System (INIS)

    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.)

  17. Determination of the density of zinc powders for alkaline battery

    Institute of Scientific and Technical Information of China (English)

    Beatriz Ares Tejero; David Guede Carnero

    2007-01-01

    The density of zinc powder for alkaline battery was determined using a pyknometer.The results showed that powders made before the end of 2003 could reach relative densities above 99% of the theoretical density.Investigating the relative volume swelling of electrolysed gels of zinc powders,no evident relation between swelling and pyknometer density was found.

  18. Review of hadrons in medium

    International Nuclear Information System (INIS)

    I review the present status in the theoretical and phenomenological understanding of hadron properties in strongly interacting matter. The topics covered are the EMC effect, nucleon structure functions in cold nuclear matter, spectral properties of light vector mesons in hot and cold nuclear matter, and in-medium properties of heavy flavored hadrons

  19. Glasma Evolution in Partonic Medium

    CERN Document Server

    Nazarenko, A V

    2010-01-01

    We examine a scenario of the abelianized Glasma evolution with accounting for back-reaction of partonic medium in ultrarelativistic heavy-ion collisions. We announce that such a generalization leads to the instabilities and the presence of negative color conductivity in the system.

  20. The Medium is the Message

    DEFF Research Database (Denmark)

    Ørum, Tania

    2016-01-01

    Danish avant-garde artists did not have the access to professional sound studios and public radio open to their colleagues in Swede, but they were equally interested in working with sound as a medium and in gaining acces to the electronic mass media. This essay examines one of the few experimental...

  1. Hadron photoproduction at medium energy

    International Nuclear Information System (INIS)

    Results from measurements of multibody photoproduction at medium incident photon energy (2.8 to 4.8 GeV) are presented and discussed. Particular emphasis is placed on topics which are not well understood and which therefore motivate experiments with the upgraded electron accelerator and storage ring ELSA at the University of Bonn, FR Germany. (author)

  2. Influence of acid and alkaline sources on optical, structural and photovoltaic properties of CdSe nanoparticles precipitated from aqueous solution

    Science.gov (United States)

    Coria-Monroy, C. Selene; Sotelo-Lerma, Mérida; Hu, Hailin

    2016-06-01

    CdSe is a widely researched material for photovoltaic applications. One of the most important parameters of the synthesis is the pH value, since it determines the kinetics and the mechanism of the reaction and in consequence, the optical and morphological properties of the products. We present the synthesis of CdSe in solution with strict control of pH and the comparison of ammonia and KOH as alkaline sources and diluted HCl as acid medium. CdSe formation was monitored with photoluminescence emission spectra (main peak in 490 nm, bandgap of CdSe nanoparticles). XRD patterns indicated that CdSe nanoparticles are mainly of cubic structure for ammonia and HCl, but the hexagonal planes appear with KOH. Product yield decreases with pH and also decreases with KOH at constant pH value since ammonia has a double function, as complexing agent and alkaline source. Changes in morphology were observed in SEM images as well with the different alkaline source. The effect of alkaline sources on photovoltaic performance of hybrid organic solar cells with CdSe and poly(3-hexylthiophene) as active layers was clearly observed, indicating the importance of synthesis conditions on optoelectronic properties of promising semiconductor nanomaterials for solar cell applications.

  3. Role of dust alkalinity in acid mobilization of iron

    Directory of Open Access Journals (Sweden)

    A. Ito

    2010-04-01

    Full Text Available Atmospheric processing of mineral aerosols by acid gases (e.g., SO2, HNO3, N2O5, and HCl may play a key role in the transformation of insoluble iron (Fe2O3 to soluble forms (e.g., Fe(II, inorganic soluble species of Fe(III, and organic complexes of iron. However, mineral dust particles also have a potential of neutralizing the acidic species due to the alkaline buffer ability of carbonate minerals (e.g., CaCO3 and MgCO3. Here we demonstrate the impact of dust alkalinity on the acid mobilization of iron in a three-dimensional aerosol chemistry transport model, which is incorporated with a mineral dissolution scheme. In our model simulations, most of the alkaline dust minerals cannot be entirely consumed by inorganic acids during the transport across the North Pacific Ocean. As a result, the inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution in aerosol solution during the long-range transport. Over the North Pacific Ocean, only a small fraction (<0.2% of iron dissolves from hematite in the coarse-mode dust aerosols, when assuming internally mixed with carbonate minerals. However, if the iron-containing minerals are externally mixed with carbonate minerals, a significant amount (1–2% of iron would dissolve from the acid mobilization. It implies that the alkaline content in dust aerosols might help to explain the inverse relationship between aerosol iron solubility and particle size.

  4. On the apparent CO2 absorption by alkaline soils

    Directory of Open Access Journals (Sweden)

    X. Chen

    2014-02-01

    Full Text Available Alkaline soils in the Gubantonggut Desert were recently demonstrated socking away large quantities of CO2 in an abiotic form. This demands a better understanding of abiotic CO2 exchange in alkaline sites. Reaction of CO2 with the moisture or dew in the soil was conjectured as a potential mechanism. The main goal of this study is to determine the extent to which the dew deposition modulates Land–Atmosphere CO2 exchange at highly alkaline sites (pH ~ 10. Experiments were conducted at the most barren sites (canopy coverage 2 fluxes were measured using a micro-lysimeters and an automated flux system (LI-COR, Lincoln, Nebraska, USA, respectively. There is an evident increase of dew deposition in nocturnal colder temperatures and decrease in diurnal warmer temperatures. Variations of soil CO2 flux are almost contrary, but the increase in diurnal warmer temperatures is obscure. It was shown that the accumulation and evaporation of dew in the soil motivates the apparent absorption and release of CO2. It was demonstrated that dew amounts in the soil has an exponential relation with the part in Fc beyond explanations of the worldwide utilized Q10 model. Therefore dew deposition in highly alkaline soils exerted a potential CO2 sink and can partly explain the apparent CO2 absorption. This implied a crucial component in the net ecosystem carbon balance (NECB at alkaline sites which occupies approximately 5% of the Earth's land surface (7 million km. Further explorations for its mechanisms and representativeness over other arid climate systems have comprehensive perspectives in the quaternary research.

  5. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  6. Electromigration in molten salts and application to isotopic separation of alkaline and alkaline-earth elements

    International Nuclear Information System (INIS)

    The separation of the isotopes of the alkaline-earth elements has been studied using counter-current electromigration in molten bromides. The conditions under which the cathode operates as a bromine electrode for the highest possible currents have been examined. For the separation of calcium, it has been necessary to use a stable CaBr2 - (CaBr2 + KBr) 'chain'. In the case of barium and strontium, it was possible to employ the pure bromides. Enrichment factors of the order of 10 for 48Ca and of the order of 1.5 for the rare isotopes of barium and strontium have been obtained. In the case of magnesium the method is slightly more difficult to apply because of material loss due to the relatively high vapour pressure of the salt requiring the use of electrolyte chains, MgBr2 - CeBr3. A study has been made that has led to a larger-scale application of the method. These are essentially the inhibition of reversible operation of the cathode by traces of water, limiting the intensity which can be tolerated; evacuation of the heat produced by the Joule effect, in the absence of which the separation efficiency is reduced by thermal gradients; corrosion of the materials by molten salts at high temperature. Several cells capable of treating a few kilograms of substance have been put into operation; none of these has lasted long enough to produce a satisfactory enrichment. The method is thus limited actually to yields of the order of a few grams. (author)

  7. Isolation of a Sulfur-oxidizing Bacterium That can Grow under Alkaline pH, from Corroded Concrete.

    Science.gov (United States)

    Maeda, T; Negishi, A; Oshima, Y; Nogami, Y; Kamimura, K; Sugio, T

    1998-01-01

    To study the early stages of concrete corrosion by bacteria, sulfur-oxidizing bacterium strain RO-1, which grows in an alkaline thiosulfate medium (pH 10.0) was isolated from corroded concreate and characterized. Strain RO-1 was a Gram negative, rod-shaped bacterium (0.5-0.6×0.9-1.5 μm). The mean G+C content of the DNA of strain RO-1 was 65.0 mol%. Optimum pH and temperature for growth were 8.0. and 30-37°C, respectively. When grown in thiosulfate medium with pH 10.0, growth rate of the strain was 48% of that observed at the optimum pH for growth. Strain RO-1 used sulfide, thiosulfate, and glucose, but not elemental sulfur or tetrathionate, as a sole energy source. Strain RO-1 grew under anaerobic conditions in pepton-NO3 (-) medium containing sodium nitrate as an electron acceptor, and had enzyme activities that oxidized sulfide, elemental sulfur, thiosulfate, sulfite, and glucose, but not tetrathionate. The bacterium had an activity to assimilate (14)CO2 into the cells when thiosulfate was used as an energy source. These results suggest that strain RO-1 is Thiobacillus versutus. Strain RO-1 exuded Ca(2+) from concrete blocks added to thiosulfate medium with pH 9.0 and the pH of the medium decreased from 9.0 to 5.5 after 22 days of cultivation. In contrast, Thiobacillus thiooxidans strain NB1-3 could not exude Ca(2+) in the same thiosulfate medium, suggesting that strain RO-1, but not T. thiooxidans NB1-3, is involved in the early stage of concrete corrosion because concrete structures just after construction contain calcium hydroxide and have a pH of 12-13. PMID:27388643

  8. Major discrepancies between results obtained with two different methods for evaluating DNA damage: alkaline elution and alkaline unwinding. Possible explanations.

    Science.gov (United States)

    Taningher, M; Bordone, R; Russo, P; Grilli, S; Santi, L; Parodi, S

    1987-01-01

    The fluorometric assay of DNA alkaline unwinding, developed by Birnboim and Jevcak (Cancer Res 41: 1889-1892, 1981) was applied to rat liver DNA, after treatment in vivo. N-nitrosodimethylamine, for which DNA damage in rat liver has been extensively investigated, was tested as a standard compound. The results were in complete agreement (both in terms of damage and repair) with data from the literature and with our own results obtained with other methods of detecting DNA alkaline fragmentation. Sensitivity was also of the same order of that of usual methods, with the effect of 0.3 mg/Kg of N-nitrosodimethylamine being detectable. Other DNA damaging carcinogens such as 1,2-dimethylhydrazine, 2-naphthylamine and dacarbazine were also correctly detected. Compounds like nitrofurantoin, benzoin and caprolactam, which appeared clearly positive with the alkaline elution technique, but for which genotoxicity and carcinogenicity are doubtful (nitrofurantoin) or most likely negative (benzoin and caprolactam), gave negative results with this method. This is also in agreement with previous results, observed using a different approach to measuring DNA unwinding. On the basis of these and other observations, we suggest that, under certain conditions, the alkaline elution technique is perhaps not only sensitive to DNA breaks but also to changes in chromatin conformation. Unwinding methods could be more specific in the detection of DNA fragmentations. PMID:3674758

  9. Estrogen and phenol red free medium for osteoblast culture: study of the mineralization ability.

    Science.gov (United States)

    de Faria, A N; Zancanela, D C; Ramos, A P; Torqueti, M R; Ciancaglini, P

    2016-08-01

    To design an estrogen and phenol red free medium for cell culture and check its effectiveness and safety on osteoblast growth it is necessary to maintain the estrogen receptors free for tests. For this purpose, we tested some modifications of the traditional culture media: estrogen depleted fetal bovine serum; estrogen charcoal stripped fetal bovine serum and phenol red free α-MEM. The aim of this work is to examine the effects of its depletion in the proliferation, differentiation, and toxicity of mesenchymal stromal cells differentiated into osteoblasts to obtain an effective interference free culture medium for in vitro studies, focused on non-previously studied estrogen receptors. We performed viability tests using the following techniques: MTT, alkaline phosphatase specific activity, formation of mineralized matrix by Alizarin technique and analysis of SEM/EDX of mineralized nodules. The results showed that the culture media with estrogen free α-MEM + phenol red free α-MEM did not impact viability, alkaline phosphatase activity and mineralization of the osteoblasts culture compared to control. In addition, its nodules possess Ca/P ratio similar to hydroxyapatite nodules on the 14th and 21st day. In conclusion, the modified culture medium with phenol red free α-MEM with estrogen depleted fetal bovine serum can be safely used in experiments where the estrogen receptors need to be free. PMID:25634598

  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. Holographic Renormalization in Dense Medium

    International Nuclear Information System (INIS)

    The holographic renormalization of a charged black brane with or without a dilaton field, whose dual field theory describes a dense medium at finite temperature, is investigated in this paper. In a dense medium, two different thermodynamic descriptions are possible due to an additional conserved charge. These two different thermodynamic ensembles are classified by the asymptotic boundary condition of the bulk gauge field. It is also shown that in the holographic renormalization regularity of all bulk fields can reproduce consistent thermodynamic quantities and that the Bekenstein-Hawking entropy is nothing but the renormalized thermal entropy of the dual field theory. Furthermore, we find that the Reissner-Nordström AdS black brane is dual to a theory with conformal matter as expected, whereas a charged black brane with a nontrivial dilaton profile is mapped to a theory with nonconformal matter although its leading asymptotic geometry still remains as AdS space

  12. Medium modifications with recoil polarization

    Energy Technology Data Exchange (ETDEWEB)

    Brand, J.F.J. van den [Nationaal Instituut voor Kernfysica en Hoge Energiefysica, Amsterdam (Netherlands); Ent, R. [CEBAF, Newport News, VA (United States)

    1994-04-01

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He({rvec e},e{prime},{rvec p}){sup 3}H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium.

  13. Medium modifications with recoil polarization

    International Nuclear Information System (INIS)

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He(rvec e,e',rvec p)3H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium

  14. Passive advection in nonlinear medium

    CERN Document Server

    Chertkov, M

    1998-01-01

    Forced advection of passive tracer, $\\theta $, in nonlinear relaxational medium by large scale (Batchelor problem) incompressible velocity field at scales less than the correlation length of the flow and larger than the diffusion scale is considered. Effective theory explaining small scale scalar fluctuations is proven to be linear, asymptotic free (downscales from the scale of the pumping) and universal. Only three parameters are required to decribe exhaustively the small scale statistics of scalar difference: two velocity-dependent ones, average and dispersion ($\\bar{\\lambda}$ and $\\Delta $ respectively) of the exponential stretching rate of a trial line element, and fluctuations. $\\alpha $ is an explicit functional of potential chracterized medium nonlinearity and amplitude of $\\theta ^{2}$ flux pumped into the system. Structure functions show an extremely anomalous, intermittent behavior: $ \\sim r^{\\xi_{q}}, \\xi_{q} = \\min {q,\\sqrt{[

  15. Screening of Alkaline Protease-Producing Streptomyces diastaticus and Optimization of Enzyme Production

    Directory of Open Access Journals (Sweden)

    Elham Dawoodi

    2014-12-01

    Full Text Available Background and Aim: Alkaline proteases are used in pharmaceutical, film and photography, silk production and food, leather and detergent industries. Actinomycetes are gram positive bacteria that produce different enzymes such as proteases. The aims of this research were isolation of native alkaline protease-producing Actinomycete spp. from different soil samples as well as optimizing the conditions for enzyme production. Materials and Methods: The different soil samples were collected from different locations of the provinces of Khouzestan, Chahar Mahalo Bakhtiari and Isfahan, Iran. After determining of the best alkaline protease producing species using Lowry method, the optimization of alkaline protease was performed. Results: The alkaline protease producing Actinomycete spp. was isolated from soil. The most enzyme activity was measured in S.diastaticus. The best concentration of sucrose as the carbon source for the highest production of alkaline protease was 10 g/l. The optimum pH and temperature for the alkaline protease production by S. diastaticus were 10 and 30°C respectively. The maximum activity of alkaline protease was measured at 200 rpm as the best aeration speed. Conclusions: This is the first report of alkaline protease production by Streptomyces diastaticus in Iran. The accomplished examinations in this research confirmed the previous theories of alkaline protease production by Actinomycetes relatively. Regarding the immense applications of alkaline proteases in several industries and isolation of a native alkaline protease producing Actinomycete, The production potential of this enzyme in our country could be accessible in the near future.

  16. Mass spectra of alkaline earth salts with a FAB source. Complexation with crown ethers

    International Nuclear Information System (INIS)

    With a liquid desorption FAB source it is possible to obtain alkaline earth metal ions complexed by a crown ether. Conditions for formation of these complexes ions are examined for selection of the complexing agent in function of cation size. Behaviour of alkaline and alkaline earth compounds are compared allowing the differentiation of ion extraction phenomena by liquid desorption ion source and solvent extraction

  17. 40 CFR 434.40 - Applicability; description of the alkaline mine drainage subcategory.

    Science.gov (United States)

    2010-07-01

    ... alkaline mine drainage subcategory. 434.40 Section 434.40 Protection of Environment ENVIRONMENTAL..., BCT LIMITATIONS AND NEW SOURCE PERFORMANCE STANDARDS Alkaline Mine Drainage § 434.40 Applicability; description of the alkaline mine drainage subcategory. The provisions of this subpart are applicable...

  18. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the...

  19. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  20. Heavy meson in nuclear medium

    CERN Document Server

    Tolos, L; Garcia-Recio, C; Molina, R; Nieves, J; Oset, E; Ramos, A

    2010-01-01

    The properties of charmed mesons in dense matter are studied using a unitary coupled-channel approach in the nuclear medium which takes into account Pauli-blocking effects and meson self-energies in a self-consistent manner. We obtain the open-charm meson spectral functions in this dense nuclear environment, and discuss their implications on hidden charm and charm scalar resonances and on the formation of $D$-mesic nuclei at FAIR.

  1. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    International Nuclear Information System (INIS)

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N2 adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation

  2. 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.

  3. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    Energy Technology Data Exchange (ETDEWEB)

    Costarrosa, L. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Calvino-Casilda, V. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Ferrera-Escudero, S. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Duran-Valle, C.J. [Dpto. de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071 Badajoz (Spain); Martin-Aranda, R.M. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain)]. E-mail: rmartin@ccia.uned.es

    2006-06-30

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N{sub 2} adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation.

  4. Lithuanian Quarry Aggregates Concrete Effects of Alkaline Corrosion Tests

    Directory of Open Access Journals (Sweden)

    Aurimas Rutkauskas

    2016-02-01

    Full Text Available Aggregate alkaline corrosion of cement in concrete is going to respond in sodium and potassium hydroxide (lye with active SiO2 found in some aggregates. During this reaction, the concrete has resulted in significant internal stresses which cause deformation of the concrete, cracking and disintegration. The reaction is slow and concrete signs of decomposition appear only after a few months or years. The study used two different aggregates quarries. Studies show that Lithuania gravel contaminated with reactive particles having amorphous silicon dioxide reacting with cement in sodium and potassium hydroxide and the resulting alkaline concrete corrosion. It was found that, according to AAR 2 large aggregates include Group II – potentially reactive because of their expansion after 14 days, higher than 0.1%.

  5. Development of Hydrogen Electrodes for Alkaline Water Electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín

    gas based infrastructure. Alkaline water electrolysis (AWE) is the current standard (stat of the art) for industrial large-scale water electrolysis systems. One of the main criteria for industrial AWE is efficient and durable electrodes. The aim of the present PhD study was to develop electrode...... nickel hydrides in electrode metal lattice. The material degradation was considerably more severe at the anode compared to the cathode. The durability single-cell measurements indicate no deactivation of electrodes after shut-downs. Microstructure investigations on the PVD Al-Ni diffusion couples at 610......Ni3 phase. The diffusion mechanism can be the key to good properties of the developed PVD Al/Ni electrodes. Electrodes produced with shorter time of diffusion, 10-30 minutes, are found to be more prone to alkaline aluminium leaching and only 4-5 wt.% of aluminium residue is found in the leached...

  6. A new electrochemical oscillatory system of bromate in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new electrochemical oscillatory system of bromate in alkaline solution is reported. In PtBromate-Alkaline solution system, two different types of electrochemical oscillations (Type Ⅰ and Type Ⅱ) can be observed. Type Ⅰ appears before hydrogen evolution and Type Ⅱ involves periodic hydrogen evolution. Type Ⅰ relates to the adsorption/desorption of the hydrogen on platinum electrode, and Type Ⅱ with periodic oscillation stems from the coupling of electrochemical reactions (the reduction of bromate and evolution hydrogen reaction) with mass transfer (diffusion and convection). More over, under the right conditions, the two types appear in different oscillatory modes, for example,simple periodical mode and mixed one, etc,, Crossed cycle in the cyclic voltammograms, which is the basiccharacteristics for electrochemical oscillatory systems, has also been observed as expected.

  7. Chemical degradation mechanisms of membranes for alkaline membrane fuel cells

    International Nuclear Information System (INIS)

    Chemical degradation mechanisms of membranes for alkaline membrane fuel cells have been investigated using density functional theory (DFT). We have elucidated that the aryl-ether moiety of membranes is one of the weakest site against attack of hydroxide ions. The results of DFT calculations for hydroxide initiated aryl-ether cleavage indicated that the aryl-ether cleavage occurred prior to degradation of cationic functional group. Such a weak nature of the aryl-ether group arises from the electron deficiency of the aryl group as well as the low bond dissociation energy. The DFT results suggests that removal of the aryl-ether group in the membrane should enhance the stability of membranes under alkaline conditions. In fact, an ether fee poly(phenylene) membrane exhibits excellent stability against the attack from hydroxide ions

  8. Chemical degradation mechanisms of membranes for alkaline membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Yoong-Kee [National Institute of Advanced Industrial Science and Technology, Umezono 1-1-1, Tsukuba (Japan); Henson, Neil J.; Kim, Yu Seung [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2015-12-31

    Chemical degradation mechanisms of membranes for alkaline membrane fuel cells have been investigated using density functional theory (DFT). We have elucidated that the aryl-ether moiety of membranes is one of the weakest site against attack of hydroxide ions. The results of DFT calculations for hydroxide initiated aryl-ether cleavage indicated that the aryl-ether cleavage occurred prior to degradation of cationic functional group. Such a weak nature of the aryl-ether group arises from the electron deficiency of the aryl group as well as the low bond dissociation energy. The DFT results suggests that removal of the aryl-ether group in the membrane should enhance the stability of membranes under alkaline conditions. In fact, an ether fee poly(phenylene) membrane exhibits excellent stability against the attack from hydroxide ions.

  9. Methanol oxidation on Pd/Pt(poly) in alkaline solution

    Science.gov (United States)

    Maksic, A.; Rakocevic, Z.; Smiljanic, M.; Nenadovic, M.; Strbac, S.

    2015-01-01

    Bimetallic electrodes prepared by Pd nanoislands spontaneously deposited on polycrystalline platinum, Pt(poly), at submonolayer coverage were explored for methanol oxidation in alkaline media. Characterization of obtained Pd/Pt(poly) nanostructures was performed ex situ by AFM imaging, spectroscopic ellipsometry and by X-ray photoelectron spectroscopy. In situ characterization of the obtained electrodes and subsequent methanol oxidation measurements were performed by cyclic voltammetry in 0.1 M KOH. Platinum surface with 35% Pd coverage exhibited the highest catalytic activity for methanol oxidation in alkaline media, exceeding those of bare Pt and Pd. Both synergistic and electronic effects are responsible for such enhanced catalysis. The origin of the synergistic effect and possible reaction pathways for methanol oxidation were discussed taking into account the activity of obtained bimetallic electrodes for the oxidation of CO and formaldehyde, as the most probable reaction intermediates.

  10. Alkaline-earth metal compounds. Oddities and applications

    International Nuclear Information System (INIS)

    This book contains the following six topics: heavy alkaline-earth metal organometallic and metal organic chemistry: synthetic methods and properties (Ana Torvisco, Karin Ruhlandt-Senge); Heavier group 2 Grignard reagents of the type aryl-ae(l)n-x post-Grignard reagents (Matthias Westerhausen, Jens Langer, Sven Krieck, Reinald Fischer, Helmar Goerls, Mathias Koehler); stable molecular magnesium(I) dimers: A fundamentally appealing yet synthetically versatile compound class (Cameron Jones, Andreas Stasch); Modern developments in magnesium reagent chemistry for synthesis (Robert E. Mulvey, Stuart D. Robertson); Alkaline-earth metal complexes in homogeneous polymerization catalysis (Jean-Francois Carpentier, Yann Sarazin); homogeneous catalysis with organometallic complexes of group 2 (Mark R. Crimmin, Michael S. Hill); Chiral Ca, Sr and Ba-catalyzed asymmetric direct-type aldol, Michael, and Mannich and related reactions (Tetsu Tsubogo, Yasuhiro Yamashita, Shu- Kobayashi).

  11. Alkaline magmatism age of Pariquera Acu Massif, SP, Brazil

    International Nuclear Information System (INIS)

    This paper presents Rb-Sr isotopic data concerning the understanding of the origin, age and emplacement of the Pariquera Acu massif, a small occurrence (3,5 x 2,5 km) of mafic ultramafic alkaline rocks discovered by aeromagnetic interpretation in 1979. The massif is situated in Sao Paulo - southeastern Brazil - near the Jacupiranga and Juquia alkaline complexes in the low Ribeira de Iguape river valley. Rb-Sr data and the K/Ar available ages in the literature of nearby complexes are discussed the characteristic aeromagnetic pattern of Pariquera Acu body and related intrusives, as well as its geology, rock types distribution and age and its relationships to the nearby complexes. (author)

  12. Bose-Einstein condensation of alkaline earth atoms: ;{40}Ca.

    Science.gov (United States)

    Kraft, Sebastian; Vogt, Felix; Appel, Oliver; Riehle, Fritz; Sterr, Uwe

    2009-09-25

    We have achieved Bose-Einstein condensation of ;{40}Ca, the first for an alkaline earth element. The influence of elastic and inelastic collisions associated with the large ground-state s-wave scattering length of ;{40}Ca was measured. From these findings, an optimized loading and cooling scheme was developed that allowed us to condense about 2 x 10;{4} atoms after laser cooling in a two-stage magneto-optical trap and subsequent forced evaporation in a crossed dipole trap within less than 3 s. The condensation of an alkaline earth element opens novel opportunities for precision measurements on the narrow intercombination lines as well as investigations of molecular states at the ;{1}S-;{3}P asymptotes. PMID:19905493

  13. Uranium distribution in dikes of alkaline and ultrabasic rocks

    International Nuclear Information System (INIS)

    Peculiarities of uraium distribution in dikes of alkaline and ultrabasic rocks of the Ukranian crystalline shield have been considered. Its behaviour in the processes of crystallization and postmagmatic change is shown on the basis of studying the substance composition and uranium distribution peculiarities in dikes. To study the uranium distribution in dikes the fragment radiography method was used. Evolution of rock structure and forms of uranium presence in the course of crystallization of subvolcanic dikes of alkaline and ultrabasic compositions has been established. At the early crystallization stage uranium concentrated in main glassy mass. With the crystallization the uranium redistribution and increase of amount of fixed uranium take place. A main part of uranium is fixed in accessories at the end crystallization stage in holocrystalline structures. Subvolcanic dikes bear traces of superimposed albitization. Uranium enrichment of albitized dikes and the character of superimposed uranium distribution testify to an earlier dike formation as compared with the sodium metasomatism process

  14. WHEAT STRAW ALKALINE LIGNIN AND ITS DERIVATIVES AS RETENTION AID

    Institute of Scientific and Technical Information of China (English)

    QuanxiaoLiu; BeihaiHe; HuaiyuZhan; ShuhuiYang; JianluLiu; ZhenxingPan; JianhuaLiu

    2004-01-01

    In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated lignin, sulfited lignin and lignin-based phenol-formaldehyde resin. The first pass retention of newsprint slurry and the properties of handsheet are improved by using the system. The results indicate that a new application field for lignin has been exploited.

  15. Alkaline Anion-Exchange Membranes Containing Mobile Ion Shuttles.

    Science.gov (United States)

    Ge, Xiaolin; He, Yubin; Guiver, Michael D; Wu, Liang; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2016-05-01

    A new class of alkaline anion-exchange membranes containing mobile ion shuttles is developed. It is achieved by threading ionic linear guests into poly(crown ether) hosts via host-guest molecular interaction. The thermal- and pH-triggered shuttling of ionic linear guests remarkably increases the solvation-shell fluctuations in inactive hydrated hydroxide ion complexes (OH(-) (H2 O)4 ) and accelerates the OH(-) transport. PMID:26972938

  16. The Origin of Life in Alkaline Hydrothermal Vents.

    Science.gov (United States)

    Sojo, Victor; Herschy, Barry; Whicher, Alexandra; Camprubí, Eloi; Lane, Nick

    2016-02-01

    Over the last 70 years, prebiotic chemists have been very successful in synthesizing the molecules of life, from amino acids to nucleotides. Yet there is strikingly little resemblance between much of this chemistry and the metabolic pathways of cells, in terms of substrates, catalysts, and synthetic pathways. In contrast, alkaline hydrothermal vents offer conditions similar to those harnessed by modern autotrophs, but there has been limited experimental evidence that such conditions could drive prebiotic chemistry. In the Hadean, in the absence of oxygen, alkaline vents are proposed to have acted as electrochemical flow reactors, in which alkaline fluids saturated in H2 mixed with relatively acidic ocean waters rich in CO2, through a labyrinth of interconnected micropores with thin inorganic walls containing catalytic Fe(Ni)S minerals. The difference in pH across these thin barriers produced natural proton gradients with equivalent magnitude and polarity to the proton-motive force required for carbon fixation in extant bacteria and archaea. How such gradients could have powered carbon reduction or energy flux before the advent of organic protocells with genes and proteins is unknown. Work over the last decade suggests several possible hypotheses that are currently being tested in laboratory experiments, field observations, and phylogenetic reconstructions of ancestral metabolism. We analyze the perplexing differences in carbon and energy metabolism in methanogenic archaea and acetogenic bacteria to propose a possible ancestral mechanism of CO2 reduction in alkaline hydrothermal vents. Based on this mechanism, we show that the evolution of active ion pumping could have driven the deep divergence of bacteria and archaea. PMID:26841066

  17. Radiation damage and photochromism in the alkaline earth fluorides

    International Nuclear Information System (INIS)

    Detailed mechanisms are proposed for the defect reactions occurring in irradiated alkaline earth fluorides. Both pure and doped crystals are considered. For the former, the models rationalise much of the experimental data, particularly the studies of Hayes and Lambourn. The discussion of doped crystals explains the origin of the pronounced effects of trivalent impurities. The mechanism of formation of photochromic centres is discussed and the observed temperature dependence of the stability of these defects is explained successfully. (author)

  18. Alkaline phosphatase for immunocytochemical labelling: problems with endogenous enzyme activity.

    OpenAIRE

    Bulman, A. S.; Heyderman, E

    1981-01-01

    Alkaline phosphatase may be used as a label for immunocytochemistry and can be demonstrated in tissue sections using the single step naphthol phosphate method. Endogenous enzyme activity may not be destroyed by fixation in formalin, formol alcohol, Carnoy's or Baker's solutions and should be inhibited before results are assessed. Either Bouin's solution or periodic acid followed by potassium borohydride are satisfactory inhibitor and do not adversely affect immunocytochemical results.

  19. In vitro fermentation response to alkaline treated sorghum grain

    Directory of Open Access Journals (Sweden)

    FARHAD PARNIAN

    2014-04-01

    Full Text Available Effects of three alkaline treatments: NaOH, NaHCO3 and wood ash on the crude protein (CP, condensed tannin (CT, neutral detergent fiber (NDF, in vitro gas production kinetics and dry matter (DM digestibility of sorghum grain were determined. The NaOH (2% w/v, NaHCO3 (2% w/v and wood ash (5% w/v treatments were completed by soaking of sorghum grain with treatment solutions in the proportion of 1 L of solution to 1 kg of grain for 12 h. Gas production was measured at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h post incubation. Alkaline treatment decreased significantly the CT (P<0.001 and NDF content (P<0.05 of sorghum grain, where it had no effect on the CP content. Treated grain with wood ash extract showed the highest (P<0.05 maximum gas production (A, and NaOH treatment trended (P<0.06 to the fastest fractional fermentation rate. Fractional rate of gas production and cumulative gas production overall incubation times except of 48 h (P<0.05 were not changed by NaHCO3 and wood ash treatment. Maximum (P<0.01 in vitro DM digestibility of alkaline treatment of sorghum grain was observed by NaOH. Cumulative volatile fatty acids concentration was increased (P<0.01 at 4h for NaOH treated compared to untreated sorghum and then decreased (P<0.001 at 48 h post incubation. Alkaline treatment of sorghum grain may become attractive due to raise in nutritive values of sorghum and hide the negative effects of its tannin in the future if the costs of other processing continue to rise.

  20. Interaction of alkali and alkaline earth ions with Ochratoxin A

    Energy Technology Data Exchange (ETDEWEB)

    Poor, Miklos [Institute of Laboratory Medicine, University of Pecs, Pecs H-7624 (Hungary); Kunsagi-Mate, Sandor; Matisz, Gergely; Li, Yin; Czibulya, Zsuzsanna [Department of General and Physical Chemistry, University of Pecs, Pecs H-7624 (Hungary); Janos Szentagothai Research Center, Pecs H-7624 (Hungary); Peles-Lemli, Beata [Department of General and Physical Chemistry, University of Pecs, Pecs H-7624 (Hungary); Koszegi, Tamas, E-mail: koszegit@freemail.hu [Institute of Laboratory Medicine, University of Pecs, Pecs H-7624 (Hungary)

    2013-03-15

    The effect of alkali and alkaline earth ions on the chemical equilibrium of mono- and dianionic forms of the mycotoxin Ochratoxin A (OTA) and their bonding onto the surface of Bovine Serum Albumin (BSA) have been investigated by fluorescence spectroscopy and fluorescence polarization techniques. Our results show that alkali metal ions shift the chemical equilibrium towards formation of dianionic form of OTA. Furthermore, the alkaline earth ions can compete with BSA for binding to OTA when these ions are present in millimolar concentrations. Our data also highlight the possibility that the 'free' fraction of OTA (not bound onto the surface of albumin) or at least a part of it is present in cation-bound form in body fluids. These observations are supported by stability constants and quantum-chemical calculations. Among the studied alkaline metal ions magnesium showed the highest affinity towards OTA under physiological conditions. Further research is required to analyze the potential significance of Mg{sup 2+}-OTA complex in cellular uptake and/or elimination of the toxin in the human body. - Highlights: Black-Right-Pointing-Pointer Fluorescence spectroscopy reveals cation-Ochratoxin A (OTA) interactions. Black-Right-Pointing-Pointer Alkali ions shift the equilibrium of OTA to formation of a dianionic structure. Black-Right-Pointing-Pointer Alkaline earth ions directly bind to OTA in the order: Mg{sup 2+}, Ca{sup 2+}, Ba{sup 2+}. Black-Right-Pointing-Pointer Quantum chemical calculations and logK values support our experimental data.

  1. Modeling diffusion of an alkaline plume in a clay barrier

    OpenAIRE

    Gaucher, Eric C.; Blanc, Philippe; Matray, Jean-Michel; Michau, Nicolas

    2004-01-01

    The design of clay plugs used for sealing access galleries to a radioactive waste repository built with concrete structures in a deep clayey formation must take into consideration their chemical evolution over time. Diffusion of an alkaline plume from concrete into bentonite was therefore modeled over a 100 ka period with the PHREEQC geochemical code in order to determine, as a function of time, modifications to mineral surfaces, dissolution of existing minerals and precipitation of new miner...

  2. Heavy metals quantification on alkaline batteries incineration emissions

    OpenAIRE

    Xará, Susana; Almeida, Manuel Fonseca; Costa, Carlos; Silva, Margarida

    2000-01-01

    Heavy metals emissions associated with municipal solid waste (MSW) incineration is a point of discussion and care due to the known harmful effects of these metals on humans and environment. Batteries are appointed as one of the main contributors for those emissions, particularly for mercury, cadmium, zinc and lead. In this paper, results for heavy metals emissions from alkaline batteries obtained in a laboratorial incinerator are presented. The incineration process took place in a tubular ove...

  3. Long range interactions between alkali and alkaline-earth atoms

    CERN Document Server

    Jiang, Jun; Mitroy, J

    2013-01-01

    Dispersion coefficients between the alkali metal atoms (Li-Rb) and alkaline-earth metal atoms (Be-Sr) are evaluated using matrix elements computed from frozen core configuration interaction calculations. Besides dispersion coefficients with both atoms in their respective ground states, dispersion coefficients are also given for the case where one atom is in its ground state and the other atom is in a low lying excited state.

  4. Laboratory study on the leaching potential of spent alkaline batteries

    OpenAIRE

    Xará, Susana M.; Delgado, Julanda N.; Almeida, Manuel F.; Costa, Carlos A.

    2009-01-01

    Four different leaching tests were carried out with spent alkaline batteries as an attempt to quantify the environmental potential burdens associated with landfilling. The tests were performed in columns filled up with batteries either entire or cross-cut, using either deionized water or nitric acid solution as leachant. In a first set of tests, the NEN 7343 standard procedure was followed, with leachant circulating in open circuit from bottom to top through columns. These tests w...

  5. Radioimmunoassay for human placental alkaline phosphatase and clinical significance

    International Nuclear Information System (INIS)

    A radioimmunoassay specific for placental alkaline phosphatase (PALP) has been performed. Sera from blood donnors contain less than 15 μg of PALP per liter. The amounts of PALP found in sera of pregnant women are higher, as soon as the first trimester of the pregnancy, increasing untill delivery (50-600 μg of PALP/l). Only 3,5% of the patients with various cancer diseases have amounts higher than 25 μg PALP/l

  6. Purification and characterization of alkaline protease from Lysinibacillus fusiformis

    OpenAIRE

    Suppiah S*; Sendeshkannan K; Prabakaran P; Rajkumar G; Yasothkumar N

    2012-01-01

    A novel alkaline protease producing bacterium was isolated from the gut of an estuarine fish Etroplus suratensis. The strain was identified by sequencing the fragment of their bacterial 16s rRNA and its homology was 97% closest to the Lysinibacillus fusiformis. An extracellular protease from this organism was purified by acetone precipitation, ion exchange chromatography and gel filtration chromatography methods and the specific activity of the purified enzyme was found to be 20.39 U/mg, 169....

  7. Co-mineralization of alkaline-earth carbonates and silica

    OpenAIRE

    Kellermeier, Matthias

    2011-01-01

    This thesis is concerned with the manifold interactions that occur when alkaline-earth metal carbonates are crystallized in the presence of dissolved silica as an additive. The described work subdivides into two main lines of research. On the one hand, an understanding of the potential roles of silica during crystallization was sought on a fundamental level. That is, the mineral - in this case calcium carbonate - was directly precipitated from silica-containing solutions and the effect on gro...

  8. Associations between Renal Hyperfiltration and Serum Alkaline Phosphatase

    OpenAIRE

    Oh, Se Won; Han, Kum Hyun; Han, Sang Youb

    2015-01-01

    Renal hyperfiltration, which is associated with renal injury, occurs in diabetic or obese individuals. Serum alkaline phosphatase (ALP) level is also elevated in patients with diabetes (DM) or metabolic syndrome (MS), and increased urinary excretion of ALP has been demonstrated in patients who have hyperfiltration and tubular damage. However, little was investigated about the association between hyperfiltration and serum ALP level. A retrospective observational study of the 21,308 adults in t...

  9. Cyanobacterial diversity in alkaline marshes of northern Belize (Central America)

    Czech Academy of Sciences Publication Activity Database

    Komárek, Jiří; Ventura, S.; Turicchia, S.; Komárková, Jaroslava; Mascalchi, C.; Soldati, E.

    2005-01-01

    Roč. 158, č. 117 (2005), s. 265-278. ISSN 0342-1120. [Symposium of the International Association for Cyanophyte Research /16./. Luxembourg, 30.08.2004-03.09.2004] R&D Projects: GA AV ČR(CZ) IAA6005309; GA AV ČR KSK6005114; GA MŠk(CZ) ME 653 Institutional research plan: CEZ:AV0Z6005908 Keywords : Cyanobacteria * alkaline marshes * Central Amerika Subject RIV: EF - Botanics

  10. Activation of Calf Intestinal Alkaline Phosphatase by Trifluoroethanol

    Institute of Scientific and Technical Information of China (English)

    曹志方; 徐真; 朴龙斗; 周海梦

    2001-01-01

    Alkaline phosphatase is a stable enzyme which is strongly resistant to urea, guanidine hydrochloride, acid pH, and heat. But there have been few studies on the effect of organic cosolvents on the activity and structure of alkaline phosphatase. The activity of calf intestinal alkaline phosphatase (CIAP) is markedly increased when incubated in solutions with elevated trifluoroethanol (TFE) concentrations. The activation is a time dependent course. There is a very fast phase in the activation kinetics in the mixing dead time (30 s) using convential methods. Further activation after the very fast phase follows biphasic kinetics. The structural basis of the activation has been monitored by intrinsic fluorescence and far ultraviolet circular dichroism. TFE (0 - 60%) did not lead to any significant change in the intrinsic fluorescence emission maximum, indicating no significant change in the tertiary structure of CIAP. But TFE did significantly change the secondary structure of CIAP, especially increasing α-helix content. We conclude that the activation of ClAP is due to its secondary structural change. The time for the secondary structure change induced by TFE preceds that of the activity increase. These results suggest that a rapid conformational change of ClAP induced by TFE results in the enhancement of ClAP activity, followed by further increase of this activity because of the further slightly slower rearrangements of the activated conformation. It is concluded that the higher catalytic activity of ClAP can be attained with various secondary structures.

  11. Mechanism of zinc electroplating in alkaline zincate solution

    Institute of Scientific and Technical Information of China (English)

    PENG Wen-jie; WANG Yun-yan

    2007-01-01

    The cathodic deposition properties and mechanism of Zn in alkaline zincate solution were studied by electrochemical techniques. The results show that Zn2+ exists in the alkaline solution in the form of Zn(OH)42-. The apparent activation energy of the electrode reaction is 38.93 kJ/mol, which indicates that the discharge of Zn(OH)42- on cathode is controlled by electrochemical polarization, and accompanied by a preceding chemical reaction. The diflusion coefficient of Zn(OH)42- is 2.452×10~cm2/s. Zn(OH)2 is the species directly discharged on the cathode surface. Based on the above results the mechanism of zinc electroplating in alkaline zincate solution was put forward.The discharged species is Zn(OH)2 formed from the preceding chemical reaction, which becomes Zn(OH)ad when gaining one electron, and then gaining the second electron to become Zn.The first electron gaining step is rate determining one.

  12. Mechanism of gold dissolving in alkaline thiourea solution

    Institute of Scientific and Technical Information of China (English)

    CHAI Li-yuan; WANG Yun-yan

    2007-01-01

    Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods, such as cyclic voltammetry, chronopotentiometry, AC impedance, linear sweep voltammetry. Apparent activation energy of anodic process of gold electrode dissolving in alkaline thiourea solution is 14.91 kJ/mol. Rate determining step is the process of gold thiourea complex diffusing away from electrode surface to solution. The results of AC impedance and chronopotentiometry indicate that thiourea adsorbs on gold electrode surface before dissolving in solution. There does not exist proceeding chemical reactions. Formamidine disulfide, the decomposed product of thiourea, does not participate the process of gold dissolution and thiourea complex. Species with electro-activity produced in the process of electrode reaction adsorbs on the electrode surface. In alkaline thiourea solution, gold dissolving mechanism undergoes the following courses: adsorption of thiourea on electrode surface; charge transfer from gold atom to thiourea molecule; Au[SC(NH2)2]ads+ receiving a thiourea molecule and forming stable Au[SC(NH2)2]2+; and then Au[SC(NH2)2]2+diffusing away from the electrode surface to solution, the last step is the rate-determining one.

  13. Alkaline static feed electrolyzer based oxygen generation system

    Science.gov (United States)

    Noble, L. D.; Kovach, A. J.; Fortunato, F. A.; Schubert, F. H.; Grigger, D. J.

    1988-01-01

    In preparation for the future deployment of the Space Station, an R and D program was established to demonstrate integrated operation of an alkaline Water Electrolysis System and a fuel cell as an energy storage device. The program's scope was revised when the Space Station Control Board changed the energy storage baseline for the Space Station. The new scope was aimed at the development of an alkaline Static Feed Electrolyzer for use in an Environmental Control/Life Support System as an oxygen generation system. As a result, the program was divided into two phases. The phase 1 effort was directed at the development of the Static Feed Electrolyzer for application in a Regenerative Fuel Cell System. During this phase, the program emphasized incorporation of the Regenerative Fuel Cell System design requirements into the Static Feed Electrolyzer electrochemical module design and the mechanical components design. The mechanical components included a Pressure Control Assembly, a Water Supply Assembly and a Thermal Control Assembly. These designs were completed through manufacturing drawing during Phase 1. The Phase 2 effort was directed at advancing the Alkaline Static Feed Electrolyzer database for an oxygen generation system. This development was aimed at extending the Static Feed Electrolyzer database in areas which may be encountered from initial fabrication through transportation, storage, launch and eventual Space Station startup. During this Phase, the Program emphasized three major areas: materials evaluation, electrochemical module scaling and performance repeatability and Static Feed Electrolyzer operational definition and characterization.

  14. Alkaline autoclave leaching of refractory uranium-thorium minerals

    International Nuclear Information System (INIS)

    This paper deals with the study of an innovative method for processing the Oman placer ores by alkaline leaching in ball mill autoclaves, where grinding and leaching of the refractory minerals take place simultaneously. This was followed by the selective separation of thorium and uranium from lanthanides by autoclave leaching of the hydroxide cake with ammonium carbonate-bicarbonate solutions. The introduced method is based on the fact that thorium and uranium form soluble carbonate complexes with ammonium carbonate, while lanthanides form sparingly soluble double carbonates. It was found that a complete alkaline leaching of Oman placer ores (98.0Percent) was attained at 150 and 175degreeC within 2.5 and 2h, respectively. Oman placer ores leaching was intensified and accelerated in a ball mill autoclaves as a result of the grinding action of steel balls, removal of the hydroxide layer covering ores grains and the continuous contact of fresh ore grains with alkaline solution. The study of selective carbonate processing of hydroxide cake with ammonium carbonate-bicarbonate solutions on autoclave under pressure revealed that the complete thorium recovery (97.5Percent) with uranium recovery (90.8Percent) and their separation from the lanthanides were attained at 70-80degreeC during l-2h. The extraction of lanthanides in carbonate solution was low and did not exceed 4.6Percent.

  15. Alkaline protease from Thermoactinomyces sp. RS1 mitigates industrial pollution.

    Science.gov (United States)

    Verma, Amit; Ansari, Mohammad W; Anwar, Mohmmad S; Agrawal, Ruchi; Agrawal, Sanjeev

    2014-05-01

    Proteases have found a wide application in the several industrial processes, such as laundry detergents, protein recovery or solubilization, prion degradation, meat tenderizations, and in bating of hides and skins in leather industries. But the main hurdle in industrial application of proteases is their economical production on a large scale. The present investigation aimed to exploit the locally available inexpensive agricultural and household wastes for alkaline protease production using Thermoactinomyces sp. RS1 via solid-state fermentation (SSF) technique. The alkaline enzyme is potentially useful as an additive in commercial detergents to mitigate pollution load due to extensive use of caustic soda-based detergents. Thermoactinomyces sp. RS1 showed good protease production under SSF conditions of 55 °C, pH 9, and 50 % moisture content with potato peels as solid substrate. The presented findings revealed that crude alkaline protease produced by Thermoactinomyces sp. RS1 via SSF is of potential application in silver recovery from used X-ray films. PMID:24122212

  16. Optimization and partial characterization of culture conditions for the production of alkaline protease from Bacillus licheniformis P003.

    Science.gov (United States)

    Sarker, Palash Kumar; Talukdar, Saimon Ahmad; Deb, Promita; Sayem, Sm Abu; Mohsina, Kaniz

    2013-01-01

    Proteolytic enzymes have occupied a pivotal position for their practical applications. The present study was carried out under shake flask conditions for the production of alkaline protease from Bacillus licheniformis P003 in basal medium containing glucose, peptone, K2HPO4, MgSO4 and Na2CO3 at pH 10. The effect of culture conditions and medium components for maximum production of alkaline protease was investigated using one factor constant at a time method along with its characterization. Maximum level of enzyme production was obtained after 48h of incubation with 2% inoculum size at 42°C, under continuous agitation at 150 rpm, in growth medium of pH 9. Highest enzyme production was obtained using 1% rice flour as carbon source and 0.8% beef extract as organic nitrogen source. Results indicated that single organic nitrogen source alone was more suitable than using in combinations and there was no significant positive effect of adding inorganic nitrogen sources in basal medium. After optimization of the parameters, enzyme production was increased about 20 fold than that of in basal medium. The crude enzyme was highly active at pH 10 and stable from pH 7-11. The enzyme showed highest activity (100%) at 50°C, and retained 78% relative activity at 70°C. Stability studies showed that the enzyme retained 75% of its initial activity after heating at 60°C for 1h. The enzyme retained about 66% and 46% of its initial activity after 28 days of storage at 4°C and room temperature (25°C) respectively. Mn(2+) and Mg(2+) increased the residual activity of the enzyme, whereas Fe(2+) moderately inhibited its residual activity. When pre-incubated with Tween-20, Tween-80, SDS and H2O2, each at 0.5% concentration, the enzyme showed increased residual activity. These characteristics may make the enzyme suitable for several industrial applications, especially in leather industries. PMID:24133650

  17. Evaluation of hydraulic conductivities of bentonite and rock under hyper alkaline and nitrate conditions

    International Nuclear Information System (INIS)

    The chemical conditions of TRU waste repository were estimated as alkaline conditions effected by cementitious materials. And, some TRU wastes include soluble nitrate salt, we have to consider the repository conditions might be high ionic strength condition leaching of nitrate salt. In this study, experimental studies were carried out to evaluate hydraulic conductivities of bentonite and rock under hyper alkaline and nitrate conditions. The followings results were obtained for bentonite. 1) In the immersion experiments of bentonite in hyper alkaline fluids with and without nitrate, the disappearance of montmorillonite of bentonite was observed and CSH formation was found after 30 days. In hyper alkaline fluid with nitrate, minerals at θ=37 nm by XRD was identified. 2) Significant effects of hyper alkaline on hydraulic conductivity of compacted bentonite were not observed. However, hydraulic conductivities of hyper alkaline fluid with nitrate and ion exchanged bentonite increased. In hyper alkaline with nitrate, more higher hydraulic conductivities of exchanged bentonite were measured. The followings results were obtained for rock. 1) In the immersion experiments of crushed tuff in hyper alkaline fluids with and without nitrate, CSH and CASH phases were observed. 2) The hydraulic conductivity of tuff in hyper alkaline fluids decreased gradually. Finally, hyper alkaline flow in tuff stopped after 2 months and hyper alkaline flow with nitrate stopped shorter than without nitrate. In the results of analysis of tuff after experiment, we could identified secondary minerals, but we couldn't find the clogging evidence of pores in tuff by secondary minerals. (author)

  18. Production and partial characterization of alkaline protease from bacillus subtilis mutant induced by gamma radiation

    International Nuclear Information System (INIS)

    Fourteen bacterial isolates belonging to B.subtilis were locally isolated from soil and screened for alkaline protease production. Only one strain, the highly potent one, was selected as alkaline protease producer and subjected to further studies to optimize its production. Alkaline protease production was maximum at 35 degree C after 72 h of incubation and at ph 10.0. molasses as a carbon source and combination of peptone and yeast extract as a nitrogen source enhanced greatly alkaline protease production. The mutant strain induced by gamma radiation showed higher alkaline protease production by 1.97 fold as compared with the parent strain. The alkaline protease enzyme was active at 40 degree C and ph 10. It was compatible with many commercial detergents and showed high stability (84 %) of its original activity with Ariel detergent. Moreover, alkaline protease enhanced the washing performance, and retained 95 % of its activity in the formulated dry powder.

  19. GEOLOGICAL MEDIUM AND UNDERGROUND HYDROSPHERE

    Directory of Open Access Journals (Sweden)

    S. V. Alekseev

    2015-09-01

    Full Text Available  The article informs about the history, the staff, researches and scientific activities of the Laboratory of Hydrogeo­logy and the Laboratory of Engineering Geology and Geoecology of the Institute of the Earth’s Crust, SB RAS. It reviews the major results of scientific research projects implemented from 2009 to 2013, which provided for determination of characteristics of the geological medium and hydrosphere of East Siberia and Mongolia in natural and technogenic conditions and mo­deling of the evolution of natural, natural-technogenic hydrogeological and engineering geological systems in regions with contrasting climate conditions and specific geological settings.  

  20. Charmed hadrons in nuclear medium

    CERN Document Server

    Tolos, L; Garcia-Recio, C; Molina, R; Nieves, J; Oset, E; Ramos, A

    2009-01-01

    We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances.

  1. Medium Theory and Social Systems

    DEFF Research Database (Denmark)

    Tække, Jesper

    The  paper  first  gives  a  tentative  theoretical  explanation  of  the  concept  of media,  based  on  the  dichotomies  of  actual/potential  (meaning),  form/medium  (appearance),  and  substratum/material  content  (extension  in  time  and  space).  This  theoretical  explanation  presents...

  2. Discrimination of alkalinity in granitoid Rocks: A potential TIMS application

    Science.gov (United States)

    Ruff, Steven W.

    1995-01-01

    In mineral exploration, the ability to distinguish and map petrochemical variations of magmatic rocks can be a useful reconnaissance tool. Alkalinity is one such petrochemical parameter and is used in the characterization of granitoid rocks. In quartz normative plutonic rocks, alkalinity is related to the composition and abundance of feldspars. Together with quartz abundance, knowledge of feldspar modes allows the classification of these igneous rocks according to the Streckeisen diagram. Alternative classification schemes rely on whole rock geochemistry instead of mineral identifications. The relative ease of obtaining whole rock analyses means that geochemical classifications tend to be favored in exploration geology. But the technique of thermal infrared spectroscopy of rocks yields information on mineralogy and is one that can be applied remotely. The goal of the current work then is to establish whether data from TIMS can be used to distinguish the mineralogical variations that relate to alkalinity. An ideal opportunity to test this thesis arises from the work presented in a paper by Dewitt (1989). This paper contains the results of mapping and analysis of Proterozoic plutonic rocks in north-central Arizona. The map resulting from this work delineates plutons according to alkalinity in an effort to establish a trend or polarity in the regional magmatism. Also contained within this paper are brief descriptions of the mineralogy of half of the region's plutons. This combination of mineralogical and geochemical information was the rationale behind choosing this area as a site for TIMS over flights. A portion of the region centered on the northern Bradshaw Mountains was selected because it contains plutons of all three alkalinity classifications (alkali-calcic, calc-alkalic, and calic) present on DeWitt's map within a relatively small area. The site was flown in August of 1994 and the data received a few days before the writing of this manuscript. Most of this

  3. Role of dust alkalinity in acid mobilization of iron

    Directory of Open Access Journals (Sweden)

    A. Ito

    2010-10-01

    Full Text Available Atmospheric processing of mineral aerosols by acid gases (e.g., SO2, HNO3, N2O5, and HCl may play a key role in the transformation of insoluble iron (Fe in the oxidized or ferric (III form to soluble forms (e.g., Fe(II, inorganic soluble species of Fe(III, and organic complexes of iron. On the other hand, mineral dust particles have a potential of neutralizing the acidic species due to the alkaline buffer ability of carbonate minerals (e.g., CaCO3 and MgCO3. Here we demonstrate the impact of dust alkalinity on the acid mobilization of iron in a three-dimensional aerosol chemistry transport model that includes a mineral dissolution scheme. In our model simulations, most of the alkaline dust minerals cannot be entirely consumed by inorganic acids during the transport across the North Pacific Ocean. As a result, the inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during the long-range transport to the North Pacific Ocean: only a small fraction of iron (<0.2% dissolves from hematite in the coarse-mode dust aerosols with 0.45% soluble iron initially. On the other hand, a significant fraction of iron (1–2% dissolves in the fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model quantitatively reproduces higher iron solubility in smaller particles as suggested by measurements over the Pacific Ocean. It implies that the buffering effect of alkaline content in dust aerosols might help to explain the inverse relationship between aerosol iron solubility and particle size. We also demonstrate that the iron solubility is sensitive to the chemical specification of iron-containing minerals in dust. Compared with the dust sources, soluble iron from combustion sources contributes to a relatively marginal effect for deposition of soluble iron over the North

  4. Change in Localization of Alkaline Phosphatase and Mannosidase II by Colchicine Treatment of Primary Cultures of Fetal Rat Hepatocytes

    International Nuclear Information System (INIS)

    We examined the changes in localization of alkaline phosphatase (ALP) and mannosidase II (man II), a Golgi marker, after colchicine treatment of primary cultures of fetal rat hepatocytes, using double immunofluorescence staining and confocal laser microscopy. In hepatocytes cultured in basal medium, ALP was localized in the perinuclear cytoplasm, and man II was observed in the Golgi region of the cytoplasm. When hepatocytes were cultured in dexamethasone-supplemented medium, ALP was also localized in the plasma membrane surrounding the bile canaliculus-like structure that was formed between adjacent cells. In hepatocytes cultured in the same medium containing colchicine, the structure of microtubules in the cytoplasm was lost, man II exhibited granular distribution scattering throughout the cytoplasm, and ALP was localized in coarse granular sites of the cytoplasm. However, ALP was not colocalized at the same sites as man II. The present study indicated that colchicine inhibits the dexamethasone-promoted translocation of ALP to the plasma membrane surrounding the bile canaliculus-like structure in primary cultures of fetal rat hepatocytes by disassembling microtubules and discomposing the Golgi complex

  5. NEW RSW & Wall Medium Fully Tetrahedral Grid

    Data.gov (United States)

    National Aeronautics and Space Administration — New Medium Fully Tetrahedral RSW Grid with viscous wind tunnel wall at the root. This grid is for a node-based unstructured solver. Medium Tet: Quad Surface Faces=...

  6. Anomalous energy losses in fractal medium

    OpenAIRE

    Panyukov, Sergey; Leonidov, Andrei

    2010-01-01

    We derive equation describing distribution of energy losses of the particle propagating in fractal medium with quenched and dynamic heterogeneities. We show that in the case of the medium with fractal dimension $2

  7. The Electrochemical Behavior of Al Alloys Containing Tin and Gallium in Alkaline Electrolytes%含镓、锡的铝合金在碱性溶液中的阳极行为

    Institute of Scientific and Technical Information of China (English)

    李振亚; 秦学; 余远彬; 陈艳英; 易玲; 杨林

    1999-01-01

    The major reason of Al anode activation is that Ga can plate out on the aluminum surface and form activated points.The Al-Sn,Al-Ga binary alloys can′ t be activated in alkaline medium.During the dissolution of the Al-Sn-Ga ternary anode,Sn and Ga dissolove solution aions as ions.After Sn ions deposit on the surface of Al anode,Ga ions will underpotentially deposit on Sn.The higher activation of the polycomponent alloy anode is caused by much more new activated points being continually formed.The activation mechanism for the polycomponent Al-alloy anode in alkaline medium is abided by the "dissolution-deposition".

  8. Neoproterozoic alkaline magmatism in Ilha do Cardoso, southeastern coast of Sao Paulo State, Brazil

    International Nuclear Information System (INIS)

    This work focuses on the geology and geochronology of rocks cropping out on Cardoso Island, on the southeastern coast of Sao Paulo State, close to the boundary with Parana State. The island, with an area of about 151 km2 is a protected area administered by the Forest Institute of the Secretariat for the Environment of the State of Sao Paulo. It is mountainous, with a peak at 814 m, and is covered by dense Atlantic Forest vegetation. The island is made up mainly of an igneous complex with light grey leucocratic, inequigranular, medium to coarse-grained syenites. The Tres Irmaos Syenite (STI), composed of pyroxene, hornblende, and perthitic to mesoperthitic microcline, predominates has magmatic flow structures, and it cut by the pinkish grey, leucocratic medium-grained Cambriu alkali-feldspar granites (GC). Geochemical analysis of STI and GC demonstrate their metaluminous alkaline nature and late orogenic to anorogenic character. The bodies formed between 620 and 570 Ma according to U-Pb dating of zircons and cooled between 597 and 531 Ma (K-Ar in amphiboles). Whole rock Sm-Nd analyses yield Meso- and Paleoproterozoic TDM ages (1,500 - 2,200 Ma). A belt of low-grade metasedimentary rocks occurs in the northern part of the island. Quartz schist, quartz-mica schist and mica-quartz schist, often-containing andalusite and cordierite, predominate. Geochemical and geochronological data suggest that the sources of the metasediments were continental arc andesites of whose protoliths separated from the mantle between 1,800 and 2,200 Ma during the Paleoproterozoic. These metasediments probably continue on the continent in the Taquari region and extend southwards in narrow strips between the granitoids of the Paranagua Domain. (author)

  9. Optimizing production of hydroxyapatite from alkaline residue for removal of Pb2+ from wastewater

    International Nuclear Information System (INIS)

    Highlights: • The solid waste from Soda Ash Plants was firstly converted into the high-efficiency adsorbent (O-HAP). • The response surface methodology was used to optimize the preparation conditions of O-HAP. • The O-HAP showed excellent immobilization ability for Pb2+ in both aqueous and soil medium. • The maximum adsorption capacity for Pb2+ (1429 mg/g) was considerably greater than other familiar adsorbents. - Abstract: Alkaline residue, a common solid waste generated from the ammonia-soda process for the production of soda ash, has been converted into hydroxyapatite for Pb2+ removal from wastewater. Response surface methodology was used to optimize the preparation conditions which were Ca/P (molar ratio), reaction temperature and reaction time, with the Pb2+ removal percentage as targeted response. The optimum conditions were identified to be Ca/P of 1.29, reaction temperature of 165.87 °C and reaction time of 14.5 h. Batch tests were conducted to evaluate the adsorption performance of optimum adsorbent (O-HAP), and the adsorption data were analyzed with different kinetic and isotherm models. The results showed that the pseudo-second order kinetic model and Langmuir isotherm model could best describe the adsorption of Pb2+ on O-HAP. The maximum adsorption capacity calculated from Langmuir equation was 1429 mg/g, which was greater than other familiar adsorbents. The MINTEQ results predicted that the formation of different Pb precipitates was the main mechanism in Pb2+ removal process, which was in good agreement with the kinetic and thermodynamic studies and were confirmed by the SEM-EDS and XRD analysis. In addition to aqueous medium, the O-HAP also could efficiently immobilize Pb2+ from contaminated soil

  10. Gravitational lensing in plasmic medium

    International Nuclear Information System (INIS)

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered

  11. Unsaturated medium hydrocarbons pollution evaluation

    International Nuclear Information System (INIS)

    When the so called porous unsaturated medium, that's the vertical subsoil section between both the ground and water-table level, is interested by a hydrocarbons spill, the problem to evaluate the pollution becomes difficult: considering, essentially, the natural coexistence in it of two fluids, air and water, and the interactions between them. This paper reports that the problems tend to increase when a third fluid, the pollutant, immiscible with water, is introduced into the medium: a three-phases flow, which presents several analogies with the flow conditions present in an oil-reservoir, will be established. In such a situation, it would be very useful to handle the matter by the commonly used parameters in the oil reservoirs studies such as: residual saturation, relative permeability, phases mobility, to derive a first semiquantitative estimation of the pollution. The subsoil pollution form hydrocarbons agents is one of the worldwide more diffused causes of contamination: such events are generally referable to two main effects: accidental (oil pipeline breakdowns, e.g.), and continuous (underground tanks breaks, industrial plants leakages, e.g.)

  12. High performance nano-Ni/Graphite electrode for electro-oxidation in direct alkaline ethanol fuel cells

    Science.gov (United States)

    Soliman, Ahmed B.; Abdel-Samad, Hesham S.; Abdel Rehim, Sayed S.; Ahmed, Mohamed A.; Hassan, Hamdy H.

    2016-09-01

    Ni/Graphite electrocatalysts (Ni/G) are successfully prepared through electrodeposition of Ni from acidic (pH = 0.8) and feebly acidic (pH = 5.5) aqueous Ni (II) baths. The efficiencies of such electrodes are investigated as anodes for direct alkaline ethanol fuel cells through their ethanol electrooxidation cyclic voltammetric (CV) response in alkaline medium. A direct proportionality between the amount of the electrodeposited Ni and its CV response is found. The amounts of the deposited Ni from the two baths are recorded using the Electrochemical Quartz Crystal Microbalance (eQCM). The Ni/G electrodes prepared from the feebly acidic bath show a higher electrocatalytic response than those prepared from the acidic bath. Surface morphology of the Ni particles electrodeposited from feebly acidic bath appears in a nano-scale dimension. Various electrochemical experiments are conducted to confirm that the Ni/G ethanol electrooxidation CV response greatly depends on the pH rather than nickel ion concentration of the deposition bath. The eQCM technique is used to detect the crystalline phases of nickel as α-Ni(OH)2/γ-NiOOH and β-Ni(OH)2/β-NiOOH and their in-situ inter-transformations during the potentiodynamic polarization.

  13. Palladium and palladium-tin supported on multi wall carbon nanotubes or carbon for alkaline direct ethanol fuel cell

    Science.gov (United States)

    Geraldes, Adriana Napoleão; Furtunato da Silva, Dionisio; Martins da Silva, Júlio César; Antonio de Sá, Osvaldo; Spinacé, Estevam Vitório; Neto, Almir Oliveira; Coelho dos Santos, Mauro

    2015-02-01

    Pd and PdSn (Pd:Sn atomic ratios of 90:10), supported on Multi Wall Carbon Nanotubes (MWCNT) or Carbon (C), are prepared by an electron beam irradiation reduction method. The obtained materials are characterized by X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Transmission electron Microscopy (TEM) and Cyclic Voltammetry (CV). The activity for ethanol electro-oxidation is tested in alkaline medium, at room temperature, using Cyclic Voltammetry and Chronoamperometry (CA) and in a single alkaline direct ethanol fuel cell (ADEFC), in the temperature range of 60-90 °C. CV analysis finds that Pd/MWCNT and PdSn/MWCNT presents onset potentials changing to negative values and high current values, compared to Pd/C and PdSn/C electrocatalysts. ATR-FTIR analysis, performed during the CV, identifies acetate and acetaldehyde as principal products formed during the ethanol electro-oxidation, with low conversion to CO2. In single fuel cell tests, at 85 °C, using 2.0 mol L-1 ethanol in 2.0 mol L-1 KOH solutions, the electrocatalysts supported on MWCNT, also, show higher power densities, compared to the materials supported on carbon: PdSn/MWCNT, presents the best result (36 mW cm-2). The results show that the use of MWCNT, instead of carbon, as support, plus the addition of small amounts of Sn to Pd, improves the electrocatalytic activity for Ethanol Oxidation Reaction (EOR).

  14. OPTIMIZATION OF THE PRODUCTION AND PARTIAL CHARACTERIZATION OF AN EXTRACELLULAR ALKALINE PROTEASE FROM THERMO-HALO-ALKALOPHILIC LONAR LAKE BACTERIA

    Directory of Open Access Journals (Sweden)

    Sandhya D Tambekar

    2013-01-01

    Full Text Available LONAR Lake, an impact crater located in the Buldhana district of Maharashtra State, India is occupied by saline water and harbors various unidentified, unique haloalkaliphilic bacterial bacillus species which produces thermo-halo-alkaliphilic proteases. The present study deals with the isolation, production dynamics, purification, characterization and optimization of a protease from Bacillus pseudofirmus, Cohnella thermotolerans and Bacillus odysseyi isolated and identified by 16S rRNA ribotyping from the Alkaline Lonar Lake. The Bacillus pseudofirmus, Cohnella thermotolerans and Bacillus odysseyi produced protease at maximum rate after 72 h of incubation at 370C with agitation speed of 120 rpm and 5% of starter culture. The best carbon sources for this Bacillus pseudofirmus, Cohnella thermotolerans and Bacillus odysseyi were fructose, maltose, starch and lactose respectively where as the best nitrogen sources were yeast extract, soy tone and soyabean cake respectively. While the most effective inorganic nitrogen sources was ammonium carbonate for Bacillus pseudofirmus, Cohnella thermotolerans and urea for Bacillus odysseyi. Supplementation of the culture medium with amino acid L-glutamic acid for Bacillus pseudofirmus and L-glycine for Cohnella thermotolerans and Bacillus odysseyi and metal ion Mg2+ for all the three bacillus species improved the protease production substantially. Under these conditions, newly isolated Bacillus pseudofirmus, Cohnella thermotolerans and Bacillus odysseyi strain were found to produce alkaline proteases at a maximum rate of optimum pH 10 and temperature at 750C.

  15. Mapping of moveout in a TTI medium

    KAUST Repository

    Stovas, A.

    2012-01-01

    To compute moveout in a transversely isotropic medium with tilted symmetry axis is a very complicated problem. We propose to split this problem into two parts. First, to compute the moveout in a corresponding VTI medium. Second, to map the computed moveout to a TTI medium.

  16. 27 CFR 19.914 - Medium plants.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Medium plants. 19.914... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Distilled Spirits For Fuel Use Permits § 19.914 Medium plants. Any person wishing to establish a medium plant shall make application for and obtain...

  17. Tin passivation in alkaline media: Formation of SnO microcrystals as hydroxyl etching product

    International Nuclear Information System (INIS)

    The mechanism of the electrochemical passivation on Tin electrodes in 0.1 M NaOH is studied at low scan rates in a wide potential range. To this aim, tin oxide layers were grown on a polycrystalline tin surface under potentiostatic conditions in both the active and passive electrochemical potential ranges, and characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that the first anodic process in the active region corresponds to the formation of a SnO·nH2O prepassive layer that is removed upon increasing the applied potential due to surface etching occurring at the metal/oxide interface. During the etching process, Sn2+ ions supersaturate at the electrode vicinity thus forming a SnO crystalline phase on top of the electrode surface in the presence of the alkaline medium. At higher anodic potentials, near the passive plateau, the etching process ceases and the current drops due to the formation of a n-type Sn(IV)-based oxide at the metal/SnO interface that provides an efficient electronic passivation of the electrode

  18. Influence of Initial Alkalinity of Lignocellulosic Waste on Their Enzymatic Degradation

    Directory of Open Access Journals (Sweden)

    Wołczyński Marcin

    2014-07-01

    Full Text Available The presented results of research on the effectiveness of enzymatic hydrolysis of lignocellulosic waste, depending on their initial depolymerisation in alkaline medium were considered in the context of the possibility of their further use in the fermentation media focused on the recovery of energy in the form of molecular hydrogen. The aim of this study was to determine the appropriate dose and concentration of a chemical reagent, whose efficiency would be high enough to cause decomposition of the complex, but without an excessive production of by-products which could adversely affect the progress and effectiveness of the enzymatic hydrolysis and fermentation. The effect of treatment on physical-chemical changes of homogenates’ properties such as pH, COD, the concentration of monosaccharide and total sugars and the concentration of total suspended solids and volatile suspended solids was determined. The enzymatic decomposition of lignocellulosic complex was repeatedly more efficient if the sample homogenates were subjected to an initial exposure to NaOH. The degree of conversion of complex sugars into simple sugars during enzymatic hydrolysis of homogenates pre-alkalized to pH 11.5 and 12.0 was 83.3 and 84.2% respectively, which should be sufficient for efficient hydrogen fermentation process.

  19. Tolerance of Chemoorganotrophic Bioleaching Microorganisms to Heavy Metal and Alkaline Stresses

    Science.gov (United States)

    Monballiu, Annick; Cardon, Nele; Tri Nguyen, Minh; Cornelly, Christel; Meesschaert, Boudewijn; Chiang, Yi Wai

    2015-01-01

    The bioleaching potential of the bacterium Bacillus mucilaginosus and the fungus Aspergillus niger towards industrial residues was investigated by assessing their response towards various heavy metals (including arsenic, cadmium, cobalt, chromium, nickel, lead, and zinc) and elevated pH. The plate diffusion method was performed for each metal to determine the toxicity effect. Liquid batch cultures were set up for more quantitative evaluation as well as for studying the influence of basicity. Growth curves were prepared using bacterial/fungal growth counting techniques such as plate counting, optical density measurement, and dry biomass determination. Cadmium, nickel, and arsenite had a negative influence on the growth of B. mucilaginosus, whereas A. niger was sensitive to cadmium and arsenate. However, it was shown that growth recovered when microorganisms cultured in the presence of these metals were inoculated onto metal-free medium. Based on the findings of the bacteriostatic/fungistatic effect of the metals and the adaptability of the microorganisms to fairly elevated pH values, it is concluded that both strains have potential applicability for further research concerning bioleaching of alkaline waste materials. PMID:26236176

  20. Tolerance of Chemoorganotrophic Bioleaching Microorganisms to Heavy Metal and Alkaline Stresses

    Directory of Open Access Journals (Sweden)

    Annick Monballiu

    2015-01-01

    Full Text Available The bioleaching potential of the bacterium Bacillus mucilaginosus and the fungus Aspergillus niger towards industrial residues was investigated by assessing their response towards various heavy metals (including arsenic, cadmium, cobalt, chromium, nickel, lead, and zinc and elevated pH. The plate diffusion method was performed for each metal to determine the toxicity effect. Liquid batch cultures were set up for more quantitative evaluation as well as for studying the influence of basicity. Growth curves were prepared using bacterial/fungal growth counting techniques such as plate counting, optical density measurement, and dry biomass determination. Cadmium, nickel, and arsenite had a negative influence on the growth of B. mucilaginosus, whereas A. niger was sensitive to cadmium and arsenate. However, it was shown that growth recovered when microorganisms cultured in the presence of these metals were inoculated onto metal-free medium. Based on the findings of the bacteriostatic/fungistatic effect of the metals and the adaptability of the microorganisms to fairly elevated pH values, it is concluded that both strains have potential applicability for further research concerning bioleaching of alkaline waste materials.

  1. Quiescent human lymphocytes do not contain DNA strand breaks detectable by alkaline elution

    International Nuclear Information System (INIS)

    On the basis of qualitative assays, quiescent lymphocytes have previously been reported to have numerous DNA strand breaks, which are thought to be repaired after mitogenic stimulation by a process associated with poly(ADP-ribosyl)ation. Using alkaline elution, a very sensitive assay for quantifying DNA single-strand breakage, the authors found no evidence for a high frequency of DNA strand breaks in unstimulated human peripheral blood lymphocytes. No differences in elution profiles were observed between unstimulated lymphocytes and lymphocytes 4 or 48 h after addition of the mitogen phytohemagglutinin (PHA). In contrast to reported studies of mouse splenic lymphocytes, they found that human lymphocytes were able to replicate and divide in the presence of the ADP-ribosylation inhibitor. Human lymphocytes were also capable of proliferating n nicotinamide-free medium, with or without 3AB, indicating that ADP-ribosylation is not a requirement for lymphocyte differentiation. They therefore consider it unlikely that peripheral human lymphocytes contain significant numbers of strand breaks that play any role in their stimulation of differentiation in response to PHA

  2. Amylase produced by Bacillus sp. SI-136 isolated from sodic-alkaline soil for efficient starch desizing

    Directory of Open Access Journals (Sweden)

    Indira P. Sarethy

    2012-12-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Bacillus sp. SI-136, isolated from sodic-alkaline soil, showed 94% similarity to B. cereus group based on 16S rDNA sequence. It produced α-amylase of 26 kDa with maximum activity at pH 10.0, stable up to pH 12.0 and 80oC. Mn2+ enhanced its activity as also 10% NaCl in medium. Agricultural waste substrates supported growth and enzyme activity was enhanced by 30% with sugarcane bagasse. The partially purified enzyme showed efficient desizing of cotton fabric at 50oC (40-60 min or 70oC (60 min with Tegewa rating 7-8, and at 95oC (20 min with Tegewa rating 9, properties enabling utility in textile industries.

  3. Effect of different carbon sources on decolourisation of an industrial textile dye under alkaline-saline conditions.

    Science.gov (United States)

    Ottoni, Cristiane; Lima, Luis; Santos, Cledir; Lima, Nelson

    2014-01-01

    White-rot fungal strains of Trametes versicolor and Phanerochaete chrysosporium were selected to study the decolourisation of the textile dye, Reactive Black 5, under alkaline-saline conditions. Free and immobilised T. versicolor cells showed 100 % decolourisation in the growth medium supplemented with 15 g l(-1) NaCl, pH 9.5 at 30 °C in liquid batch culture. Continuous culture experiments were performed in a fixed-bed reactor using free and immobilised T. versicolor cells and allowed 85-100 % dye decolourisation. The immobilisation conditions for the biomass and the additional supply of carbon sources improved the decolourisation performance during a long-term trial of 40 days. Lignin peroxidase, laccase and glyoxal oxidase activities were detected during the experiments. The laccase activity varied depending on carbon source utilized and glycerol-enhanced laccase activity compared to sucrose during extended growth. PMID:23982200

  4. 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.

  5. Conductivities in an anisotropic medium

    CERN Document Server

    Khimphun, Sunly; Park, Chanyong

    2016-01-01

    In order to imitate anisotropic medium of a condensed matter system, we take into account an Einstein-Maxwell-dilaton-axion model as a dual gravity theory where the anisotropy is caused by different momentum relaxations. This gravity model allows an anisotropic charged black hole solution. On this background, we investigate how the linear responses of vector modes like electric, thermoelectric, and thermal conductivities rely on the anisotropy. We find that the electric conductivity in low frequency limit shows a Drude peak and that in the intermediate frequency regime it reveals the power law behavior. Especially, when the anisotropy increases the exponent of the power law becomes smaller. In addition, we find that there exist a critical value for the anisotropy at which the DC conductivity reaches to its maximum value.

  6. Zirconium behaviour in nitric medium

    International Nuclear Information System (INIS)

    Zirconium in nitric solutions exhibits an excellent corrosion resistance in the passive state, and a mediocre corrosion resistance in the unpassive state with risk of stress corrosion cracking. Results of the influence of some parameters (medium, potential, temperature, stress, friction, metallurgical structure and surface state) on zirconium passivation are presented. Zirconium remains passive in a large range of HNO3 concentration (at least up to 14.4N), in the presence of oxidizing ions (Cr4, Ce4), in a spent fuel dissolution solution. Zirconium is depassived by friction at high speed and pressure, by platinum coupling in boiling 14.4N HNO3 with or without stress, or by imposed deformation speed under high potential. (A.B.). 8 figs., 2 tabs

  7. Cushioning medium for discarding radioactive waste

    International Nuclear Information System (INIS)

    A cushioning medium for discarding radioactive wastes is disposed in a discarding hole formed underground. The cushioning medium is formed by drying and solidifying a mixture of clays and sands. A lower cushioning medium has a cylindrical containing hole at the central portion of a cylindrical bottomed cushioning medium main body. A cylindrical metal overpack containing radioactive wastes such as glass solidification materials is contained in the containing hole. An upper cushioning medium situated above the lower cushioning medium has an communication hole having a circular cross section at the central portion of the cylindrical buffer main body. A protection member formed of a metal plate is disposed on the inner surface of the containing hole of the lower cushioning medium and the communication hole of the upper cushioning medium. A plug cushioning medium situated in the upper cushioning medium is formed of a solid cylindrical body, and fitted into the communication hole of the upper cushioning medium to close the communication hole, being situated above the overpack. (I.N.)

  8. Purification and characterization of alkaline proteases from aspergillus terreus

    International Nuclear Information System (INIS)

    Proteases belong to an important class of enzymes known as hydrolases and catalyze hydrolysis of proteins. They act primarily to degrade proteins that are used for energy production and as biosynthetic precursors. In the following study, protease produced from Aspergillus terreus was found to be thermo stable and included in the category of alkaline serine and metallo protease. During partial purification, presence of enzyme in 60% (NH/sub 4/)/sub 2/SO/sub 4/ indicated small molecular weight polypeptide; later purification with Sephadex G-75 fractionation yielded a single proteolytic active molecule. At final purification step, the increase in specific activity of the enzyme was 7.5 fold with 23% yield. SDS-PAGE analysis revealed that alkaline protease of Aspergillus terreus is a monomer with approximate molecular weight of 35 kDa. Optimum pH for protease activity was found in the range of 7.5-11.0 (maximum at pH 8.5), thus apparently classified as an alkaline protease. The enzyme was thermo stable towards high temperature (60 deg. C), however it denatured irreversibly at 70 deg. C showing 80% loss of activity. The maximum proteolytic activity was found at 40 deg. C. The enzyme was effectively inhibited by PMSF, EDTA and urea whereas iodoacetamide and thiourea did not result in any loss in activity while cysteine was found to be activator molecule. The study with metal ions Mg/sup +2/, Mn/sup +2/ and Fe/sup +3/ (1 mM each) showed minute stimulatory effects on enzyme activity. Co/sup +2/ and Ca/sup +2/ (1 mM) had neither excitatory nor inhibitory effect while Hg/sup +2/ and Cu/sup +2/ (1 mM) slightly reduced the enzyme activity. (author)

  9. Growth of microbial mixed cultures under anaerobic, alkaline conditions

    International Nuclear Information System (INIS)

    Cement and concrete are the most important engineered barrier materials in a repository for low- and intermediate-level waste and thus represent the most significant component of the total disposal inventory. Based on the chemical composition of the concrete used in the repository and the groundwater fluxes in the modelled host rock, it is to be expected that the pH in the near vicinity of the repository could exceed a value of 10.5 for more than a million years. The groundwater in the repository environment also has a limited carbon concentration. Since microorganisms will be present in a repository and can even find suitable living conditions within the waste itself, investigations were carried out in order to establish the extent to which microbial activity is possible under the extreme conditions of the repository near-field. For the investigations, alkalophilic cultures were enriched from samples from alkaline habitats and from Valanginian Marl. Anaerobic bacteria with fermentative, sulfate-reducing and methanogenic metabolism were selected. The growth and activity of the mixed cultures were studied under alkaline conditions and the dependence on pH and carbon concentration determined. All the mixed cultures investigated are alkalophilic. The optimum growth range for the cultures is between pH 9.0 and pH 10.0. The activity limit for the fermentative mixed culture is at pH 12, for the sulfate-reducers at pH 11 and for the methanogens at pH 10.5. Given the limited supply of carbon, the mixed cultures can only grow under slightly alkaline conditions. Only the fermentative cultures are capable of surviving with limited carbon supply at pH 13. (author) 24 figs., 18 tabs., 101 refs

  10. 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

  11. Rapid, Effective DNA Isolation from Osmanthus via Modified Alkaline Lysis.

    Science.gov (United States)

    Alexander, Lisa

    2016-07-01

    Variability of leaf structure and presence of secondary metabolites in mature leaf tissue present a challenge for reliable DNA extraction from Osmanthus species and cultivars. The objective of this study was to develop a universal rapid, effective, and cost-efficient method of DNA isolation for Osmanthus mature leaf tissue. Four different methods were used to isolate DNA from 8 cultivars of Osmanthus. Absorbance spectra, DNA concentration, appearance on agarose gel, and performance in PCR were used to analyze quality, quantity, and integrity of isolated DNA. Methods were ranked in order, based on total quantity, quality, and performance points as the following: 1) solid-phase extraction (SPE), 2) modified alkaline lysis (SDS), 3) cetyltrimethylammonium bromide (CTAB) with chloroform (CHL), and 4) CTAB with phenol/chloroform (PHE). Total DNA, isolated via SPE, showed the least contamination but the lowest mean quantity (9.6 ± 3.4 μg) and highest cost. The highest quantity of DNA was isolated via SDS (117 ± 54.1 μg). SPE and SDS resolved the most individuals on agarose gel, whereas the 2 CTAB methods had poorly resolved gels. All methods except PHE performed well in PCR. Additions to the modified alkaline lysis method increased A260:A230 by up to 59% without affecting yield. With the use of SDS, an average of 1000 μg/g DNA was isolated from fresh leaf tissue of 18 samples in ∼1.5 h at a cost of 0.74 U.S. dollars (USD)/sample. We recommend improved alkaline lysis as a rapid, effective, and cost-efficient method of isolating DNA from Osmanthus species. PMID:26816495

  12. Pyroxenes of the Khibiny alkaline pluton, Kola Peninsula

    Science.gov (United States)

    Yakovenchuk, V. N.; Ivanyuk, G. Yu.; Pakhomovsky, Ya. A.; Men'shikov, Yu. P.; Konopleva, N. G.; Korchak, Yu. A.

    2008-12-01

    Seven pyroxene varieties were identified in nepheline syenites and foidolites of the Khibiny pluton: enstatite, ferrosilite, diopside, hedenbergite, augite, aegirine-augite, and aegirine. Enstatite and augite are typical of alkaline and ultramafic rocks of dike series. Ferrosilite was found in country quartzitic hornfels. Diopside is a rock-forming mineral in alkaline and ultramafic rocks, alkali gabbroids, hornfels in xenoliths of volcanic and sedimentary rocks and foyaite, melteigite-urtite that assimilate them, and certain hydrothermal pegmatite veins. Hedenbergite was noted in hornfels from xenoliths of volcanic and sedimentary rocks and in a hydrothermal pegmatite vein at Mount Eveslogchorr. Aegirine-augite is the predominant pyroxene in all types of nepheline syenites, phonolites and tinguaites, foidolites, alkaline and ultramafic rocks of dike series, fenitized wall rocks surrounding the pluton, and xenoliths of Devonian volcanic and sedimentary rocks. Aegirine is an abundant primary or, more often, secondary mineral in nepheline syenites, foidolites, and hydrothermal pegmatite veins. It occurs as separate crystals, outer zones of diopside and aegirine-augite crystals, and homoaxial pseudomorphs after Na-Ca amphiboles. Microprobe analyses of 265 pyroxenes samples allowed us to distinguish ten principal trends of isomorphic replacement and corresponding typomorphic features of pyroxenes. Compositional variations in clinopyroxenes along the sampled 35-km profile from the margin of the Khibiny pluton to its center confirm the symmetric zoning of the foyaite pluton relative to semicircular faults of the Minor Arc and the Main (Central) Ring marked by Devonian volcanic and sedimentary rocks, foidolites, and related metasomatic rocks (rischorrite, albitite, and aegirinite). Changes in the composition of pyroxenes are explained mainly by the redistribution of elements between coexisting minerals of foyaites in the process of their intense differentiation under the

  13. HYDROGEN SULFIDE ADSORPTION BY ALKALINE IMPREGNATED COCONUT SHELL ACTIVATED CARBON

    Directory of Open Access Journals (Sweden)

    HUI SUN CHOO

    2013-12-01

    Full Text Available Biogas is one type of renewable energy which can be burnt to produce heat and electricity. However, it cannot be burnt directly due to the presence of hydrogen sulfide (H2S which is highly corrosive to gas engine. In this study, coconut shell activated carbon (CSAC was applied as a porous adsorbent for H2S removal. The effect of amount of activated carbon and flow rate of gas stream toward adsorption capacity were investigated. Then, the activated carbons were impregnated by three types of alkaline (NaOH, KOH and K2CO3 with various ratios. The effects of various types of alkaline and their impregnation ratio towards adsorption capacity were analysed. In addition, H2S influent concentration and the reaction temperature on H2S adsorption were also investigated. The result indicated that adsorption capacity increases with the amount of activated carbon and decreases with flow rate of gas stream. Alkaline impregnated activated carbons had better performance than unimpregnated activated carbon. Among all impregnated activated carbons, activated carbon impregnated by K2CO3 with ratio 2.0 gave the highest adsorption capacity. Its adsorption capacity was 25 times higher than unimpregnated activated carbon. The result also indicated that the adsorption capacity of impregnated activated carbon decreased with the increment of H2S influent concentration. Optimum temperature for H2S adsorption was found to be 50˚C. In this study, the adsorption of H2S on K2CO3 impregnated activated carbon was fitted to the Langmuir isotherm. The fresh and spent K2CO3 impregnated activated carbon were characterized to study the adsorption process.

  14. Separator Materials Used in Secondary Alkaline Batteries Characterized and Evaluated

    Science.gov (United States)

    1996-01-01

    Nickel-cadmium (Ni/Cd) and nickel-hydrogen (Ni/H2) secondary alkaline batteries are vital to aerospace applications. Battery performance and cycle life are significantly affected by the type of separators used in those batteries. A team from NASA Lewis Research Center's Electrochemical Technology Branch developed standardized testing procedures to characterize and evaluate new and existing separator materials to improve performance and cycle life of secondary alkaline batteries. Battery separators must function as good electronic insulators and as efficient electrolyte reservoirs. At present, new types of organic and inorganic separator materials are being developed for Ni/Cd and Ni/H2 batteries. The separator material previously used in the NASA standard Ni/Cd was Pellon 2505, a 100-percent nylon-6 polymer that must be treated with zinc chloride (ZnCl2) to bond the fibers. Because of stricter Environmental Protection Agency regulation of ZnCl2 emissions, the battery community has been searching for new separators to replace Pellon 2505. As of today, two candidate separator materials have been identified; however, neither of the two materials have performed as well as Pellon 2505. The separator test procedures that were devised at Lewis are being implemented to expedite the search for new battery separators. The new test procedures, which are being carried out in the Separator Laboratory at Lewis, have been designed to guarantee accurate evaluations of the properties that are critical for sustaining proper battery operation. These properties include physical and chemical stability, chemical purity, gas permeability, electrolyte retention and distribution, uniformity, porosity, and area resistivity. A manual containing a detailed description of 12 separator test procedures has been drafted and will be used by the battery community to evaluate candidate separator materials for specific applications. These standardized procedures will allow for consistent, uniform

  15. Medium-Based Design: Extending a Medium to Create an Exploratory Learning Environment

    Science.gov (United States)

    Rick, Jochen; Lamberty, K. K.

    2005-01-01

    This article introduces "medium-based" design -- an approach to creating "exploratory learning environments" using the method of "extending a medium". First, the characteristics of exploratory learning environments and medium-based design are described and grounded in related work. Particular attention is given to "extending a medium" --…

  16. A description of alkaline phosphatases from marine organisms

    Science.gov (United States)

    Tian, Jiyuan; Jia, Hongbing; Yu, Juan

    2015-12-01

    Alkaline phosphatases (APs) are non-specific phosphohydrolases, and they are widely used in clinical diagnostics and biological studies. APs are widespread in nature and exhibit different structural formulations. Based on the diversity of biogenetic sources, APs exhibit temperature-propensity traits, and they are classified as psychrophilic, mesophilic, and thermophilic. In this article, the characteristics of psychrophilic APs from marine organisms were described, accompanied by a simple description of APs from other organisms. This review will facilitate better utilization of marine APs in the biotechnology field.

  17. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Gary M. Blythe

    2001-11-06

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period April 1, 2001 through September 30, 2001. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO{sub x} selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. During the current period, American Electric Power (AEP) joined the project as an additional co-funder and as a provider of a host site for testing. This is the fourth reporting period for the subject Cooperative Agreement. During this period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Station. These tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Station), and a byproduct magnesium hydroxide slurry (both Gavin Station and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70 to 75% sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Station, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NO

  18. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Gary M. Blythe

    2002-04-29

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period October 1, 2001 through March 31, 2002. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO{sub X} selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, American Electric Power (AEP) and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. This is the fifth reporting period for the subject Cooperative Agreement. During the previous (fourth) period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Plant. Those tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Plant) and a byproduct magnesium hydroxide slurry (at both Gavin and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70-75% overall sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NO{sub X} control than at removing SO{sub 3} formed in the furnace. The SO{sub 3} removal results were presented

  19. Chromatographic separation of alkaline phosphatase from dental enamel

    DEFF Research Database (Denmark)

    Moe, D; Kirkeby, S; Salling, E

    1989-01-01

    Alkaline phosphatase (AP) was prepared from partly mineralized bovine enamel by extraction in phosphate buffer, centrifugation and various chromatographic techniques. Chromatofocusing showed that the enamel enzyme possessed five isoelectric points at the acid pH level ranging from pH 5.7 to pH 4.......4. Three enzyme peaks were eluted using low pressure chromatography with a Bio-gel column. With a HPLC gel filtration column the separation of the enamel extract resulted in only one peak with AP activity. The fractions of this peak were used to produce an antibody against bovine AP....

  20. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...... cell. In the present work we demonstrate the application of hydrophobic, porous, and electro-catalytically active gas diffusion electrodes. PTFE particles and silver nanowires as electro-catalysts were used in the gas diffusion electrodes. Impedance spectroscopy and cyclic voltammetry were performed to...

  1. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into chemical energy in the form of hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and a liquid immobilized electrolyte allow the operation of...... the newly designed electrolysis cell as a fuel cell, but condensation of steam may lead to blocked pores, thereby inhibiting gas diffusion and decreasing the performance of the cell. In the here presented work we present the application of a hydrophobic, porous, and electro-catalytically active layer...

  2. ALKALINE PHOSPHATASE ACTIVITY AS A MARKER OF DOG SEMEN FREEZABILITY

    Directory of Open Access Journals (Sweden)

    KOSINIAK-KAMYSZ K.

    2007-01-01

    Full Text Available The investigation was performed to evaluate the dog semen freezability and itsquality after thawing allowing its use for artificial insemination (AI. On the basis ofsperm motility, concentration and alkaline phosphatase (AP activity in semenplasma it was possible to establish that AP activity corresponds with the basic factorof semen examination. Significant statistical differences occurred between thequality of ejaculates which were qualified or disqualified to deep freezing and AI.These results show that AP activity in raw dog semen plasma can be used as amarker for the dog semen qualification for deep freezing and AI with 95%probability of the prognosis of the results.

  3. Structural variations in layered alkaline earth metal cyclohexyl phosphonates

    Indian Academy of Sciences (India)

    Ramaswamy Murugavel; Nayanmoni Gogoi

    2009-06-01

    Two series of alkaline earth metal cyclohexyl phosphonates, M(C6H11PO3H)2(H2O) (M = Ca, Sr and Ba) (1–3) and M(C6H11PO3)(H2O) (M = Mg, Ca, Sr, and Ba) (4–7) have been synthesized under mild reaction conditions. All new compounds have been characterized using elemental analysis, IR, TGA and powder X-ray diffraction techniques. The molecular structure of compound 2 determined using single crystal X-ray diffraction technique reveals a layered polymeric structure.

  4. Lyoluminescence of luminol in aqueous alkaline metal hydroxides

    International Nuclear Information System (INIS)

    The lyoluminescence emission spectra of luminol, induced by γ-irradiated NaCl in aqueous alkaline earth metal hydroxides, are recorded. Continuous emission bands are observed in the visible region from 390 to 535 nm. These emission bands on resolution showed two peaks at 430 and 460 nm, respectively in all hydroxides. An additional band of 490 appears in the case of calcium hydroxide. The colour centres released during disintegration of irradiated NaCl crystals in aqueous solution react with luminol to produce various excited molecular species, which are responsible for observed lyoluminescence of luminol. (author) 26 refs.; 7 figs.; 1 tab

  5. Chemical degradation of fluoroelastomer in an alkaline environment

    DEFF Research Database (Denmark)

    Mitra, S.; Ghanbari-Siahkali, A.; Kingshott, P.;

    2004-01-01

    We have investigated the time-dependent chemical degradation of a fluoroelastomer, FKM (Viton((R)) A), in an alkaline environment (10% NaOH, 80 degreesC). Optical microscopy and SEM analysis reveal that degradation starts with surface roughness right from the earliest stage of exposure (e.g., 1...... week) and finally results in cracks on the surface after prolonged exposure. Initially the extent of degradation is mainly confined to the surface regions (a few nanometers) but with longer exposure (e.g., 12 weeks) it extends to below the subsurface region of the fluoroelastomer. The extent of this...

  6. Combined wet oxidation and alkaline hydrolysis of polyvinylchloride

    DEFF Research Database (Denmark)

    Sørensen, E.; Bjerre, A.B.

    1992-01-01

    In view of the widespread aversion to burning polyvinylchloride (PVC) together with municipal waste, we have attempted an alternative approach to its decomposition. This paper describes a combined wet oxidation/alkaline hydrolysis yielding water soluble, biodegradable products. Experiments were...... carried out at temperatures from 180-260 degree C and reaction times of 8-24 min. The chloride liberated provides information on the rate constants. Considering the measured Cl- and Chemical Oxygen Demand (COD) values, we find hydrolysis and oxidation processes to be interdependent. The main products are...

  7. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL; SEMIANNUAL

    International Nuclear Information System (INIS)

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period October 1, 2001 through March 31, 2002. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO(sub X) selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, American Electric Power (AEP) and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. This is the fifth reporting period for the subject Cooperative Agreement. During the previous (fourth) period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Plant. Those tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Plant) and a byproduct magnesium hydroxide slurry (at both Gavin and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70-75% overall sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO(sub 3) formed across the SCR system installed on the unit for NO(sub X) control than at removing SO(sub 3) formed in the furnace. The SO(sub 3) removal results were presented in the

  8. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL; SEMIANNUAL

    International Nuclear Information System (INIS)

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period April 1, 2001 through September 30, 2001. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO(sub x) selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. During the current period, American Electric Power (AEP) joined the project as an additional co-funder and as a provider of a host site for testing. This is the fourth reporting period for the subject Cooperative Agreement. During this period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Station. These tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Station), and a byproduct magnesium hydroxide slurry (both Gavin Station and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70 to 75% sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Station, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO(sub 3) formed across the SCR system installed on the unit for NO(sub x

  9. Porous poly(perfluorosulfonic acid) membranes for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Aili, David; Hansen, Martin Kalmar; Andreasen, Jens Wenzel;

    2015-01-01

    Poly(perfluorosulfonic acid) (PFSA) is one of a few polymer types that combine excellent alkali resistance with extreme hydrophilicity. It is therefore of interest as a base material in separators for alkaline water electrolyzers. In the pristine form it, however, shows high cation selectivity. To...... increase its ion conductivity in aqueous KOH, a method for the preparation of porous PFSA membranes was developed. It was based on an approach where PFSA was co-cast with poly(vinylpyrrolidone) (PVP) at different ratios to give transparent and colorless blend membranes. The PVP was subsequently dissolved...

  10. A description of alkaline phosphatases from marine organisms

    Science.gov (United States)

    Tian, Jiyuan; Jia, Hongbing; Yu, Juan

    2016-07-01

    Alkaline phosphatases (APs) are non-specific phosphohydrolases, and they are widely used in clinical diagnostics and biological studies. APs are widespread in nature and exhibit different structural formulations. Based on the diversity of biogenetic sources, APs exhibit temperature-propensity traits, and they are classified as psychrophilic, mesophilic, and thermophilic. In this article, the characteristics of psychrophilic APs from marine organisms were described, accompanied by a simple description of APs from other organisms. This review will facilitate better utilization of marine APs in the biotechnology field.

  11. In vitro fermentation response to alkaline treated sorghum grain

    OpenAIRE

    FARHAD PARNIAN; AKBAR TAGHIZADEH; HAMID PAY; BABAK BAGHBANZADEH NOBARI

    2014-01-01

    Effects of three alkaline treatments: NaOH, NaHCO3 and wood ash on the crude protein (CP), condensed tannin (CT), neutral detergent fiber (NDF), in vitro gas production kinetics and dry matter (DM) digestibility of sorghum grain were determined. The NaOH (2% w/v), NaHCO3 (2% w/v) and wood ash (5% w/v) treatments were completed by soaking of sorghum grain with treatment solutions in the proportion of 1 L of solution to 1 kg of grain for 12 h. Gas production was measured at 2, 4, 6, 8, 12, 16, ...

  12. Development of a pressurized bipolar alkaline water electrolyzer

    Energy Technology Data Exchange (ETDEWEB)

    Neves Junior, Newton Pimenta; Pinto, Edgar A. de Godoi Rodrigues; Silva, Ennio Peres da; Rapelli, Rubia; Pinto, Cristiano da Silva [Universidade Estadual de Campinas (DFA/ IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Dept. de Fisica Aplicada], Email: nevesjr@unicamp.br; Marin Neto, Antonio Jose; Lopes, Daniel Gabriel; Camargo, Joao Carlos; Ferreira, Paulo F.P. [Hydrogen Technology (HyTron), Campinas, SP (Brazil); Furlan, Andre Luis [Universidade Estadual de Campinas (DE/FEC/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica

    2010-07-01

    This paper reports the actual development status of a bipolar alkaline water electrolyzer with maximum production capacity of 1 m3/h of hydrogen and controlled by a PLC (Programmable Logic Controller), which also interfaces the electrolytic system with operators and other equipment, such as gas storage tanks, fuel cells and photovoltaic panels. The project also includes the construction of an electrolysis test bench to record electrical parameters (cathode, anode, separator and electrolyte potentials), the amount of produced gases and gas quality determined by gas chromatography. (author)

  13. Processing of Malaysian xenotime using the alkaline leaching method

    International Nuclear Information System (INIS)

    Apart from being used as a red phosphor in colour television tubes, yttrium is also used as an oxygen detector, optical lenses, advance ceramic materials as well as in the manufacturing of superconductor. Xenotime is a main source of yttrium and is obtained as an industrial by product from tin mining. The present work shows how xenotime is processed by the alkaline leaching method. The results points that the method is comparatively superior than the conventional, namely sulfuric acid leaching. Some of the advantages of the process are purer product, more economics, an environmental friendly by-products and process

  14. A double antibody radioimmunoassay specific for placental alkaline phosphatase

    International Nuclear Information System (INIS)

    Placental alkaline phosphatase (PLAP) is normally found in enzymically measurable amounts in second and third trimester pregnancy serum. Its occurrence in sera and tumours from patients with malignant disease has led to the development of methods to specifically identify and quantitate the enzyme. Recently immunological techniques have been used, employing antibodies raised to purified PLAP; these include solid phase radioimmunoassays and enzyme-immunoassay. The development of a sensitive, specific, automated double-antibody radioimmunoassay for the measurement of PLAP in serum is reported. (Auth.)

  15. ALKALINE PHOSPHATASE ACTIVITY AS A MARKER OF DOG SEMEN FREEZABILITY

    Directory of Open Access Journals (Sweden)

    K. KOSINIAK-KAMYSZ

    2013-12-01

    Full Text Available The investigation was performed to evaluate the dog semen freezability and itsquality after thawing allowing its use for artificial insemination (AI. On the basis ofsperm motility, concentration and alkaline phosphatase (AP activity in semenplasma it was possible to establish that AP activity corresponds with the basic factorof semen examination. Significant statistical differences occurred between thequality of ejaculates which were qualified or disqualified to deep freezing and AI.These results show that AP activity in raw dog semen plasma can be used as amarker for the dog semen qualification for deep freezing and AI with 95%probability of the prognosis of the results.

  16. Kinetics studies of oxidation of niacinamide by alkaline potassium permanganate

    OpenAIRE

    Sandipsingh Gour; Sayyed Hussain; Mazahar Farooqui

    2012-01-01

    The oxidation of niacinamide in alkaline media is carried out using potassium permanganate as a oxiding agent. The reaction was monitored using UV-Visible spectrophotometer at 525 nm. It was found to be zero order with respect to oxidant,, fractional order with respect to hydrogen ion concentration and first order with respect to substrate. The thermodynamic parameters(were determinied . The average (?G#) was found to be 87.60 KJ/mol. The values ?S# was found to be -0.2132 K...

  17. Hyper production of alkaline protease by mutagenized bacillus subtilis

    International Nuclear Information System (INIS)

    The purpose of this work was to augment the alkaline protease production from Bacillus subtilis by using chemical mutagen (MMS) and UV mutagenesis. A number of mutants were isolated which produce high levels of extra cellular proteases. Analysis of culture supernatants of these mutants had shown that the total amounts of proteolysis activity were increased from 1 to 2 fold over the wild strain. Clones showing promote response were further characterized by analyzing different parameters; like of Temperature, pH substrate concentration and incubation period, to study the activity of protease enzyme. (author)

  18. Mechanistic studies of the alkaline degradation of cellulose in cement

    International Nuclear Information System (INIS)

    The alkaline degradation of cellulose-based materials under conditions simulating those of a deep underground radioactive waste repository has been investigated. A number of key degradation products, of which 2-C-(hydroxymethyl)-3-deoxy-D-pentonic acid (isosaccharinic acid) is the most important, have been synthesised, and the solubilities of their plutonium complexes have been determined. Analysis of leachates of anaerobically degraded cellulose has shown concentrations of organic acids which are broadly consistent with the enhanced plutonium solubilities found in these leachates. Reaction mechanisms have been identified that can lead to isosaccharinic acid production by non-oxidative transformations, which may be catalysed by some divalent cations. (Author)

  19. Bose-Einstein condensation of alkaline earth atoms: $^{40}${Ca}

    OpenAIRE

    Kraft, Sebastian; Vogt, Felix; Appel, Oliver; Riehle, Fritz; Sterr, Uwe

    2009-01-01

    We have achieved Bose-Einstein condensation of $^{40}$Ca, the first for an alkaline earth element. The influence of elastic and inelastic collisions associated with the large ground state s-wave scattering length of $^{40}$Ca was measured. From these findings, an optimized loading and cooling scheme was developed that allowed us to condense about $2 \\cdot 10^4$ atoms after laser cooling in a two-stage magneto-optical trap and subsequent forced evaporation in a crossed dipole trap within less ...

  20. Alkalinity and trophic state regulate aquatic plant distribution in Danish lakes

    DEFF Research Database (Denmark)

    Vestergaard, Ole Skafte; Sand-Jensen, Kaj

    2000-01-01

    distinct differences in the distribution of species and growth forms among the lakes. The lakes separated into five groups of characteristic species compositions. Alkalinity was the main factor responsible for the species distribution. Lakes of high alkalinity were dominated by vascular plants......Main distribution patterns of submerged macrophytes in a large number of Danish lakes were determined and relationships to environmental variables evaluated by different multivariate analysis techniques. The lakes varied greatly in location, size, depth, alkalinity and trophic status. There were...... of the elodeid growth form, lakes of intermediate alkalinity contained a variety of elodeids and vascular plants of the isoetid growth form, while lakes of low alkalinity and low pH had several isoetids and bryophytes, but very few elodeids. Alkalinity is a close descriptor of the bicarbonate concentration...

  1. Stability for a novel low-pH alkaline slurry during the copper chemical mechanical planarization

    International Nuclear Information System (INIS)

    The stability of a novel low-pH alkaline slurry (marked as slurry A, pH = 8.5) for copper chemical mechanical planarization was investigated in this paper. First of all, the stability mechanism of the alkaline slurry was studied. Then many parameters have been tested for researching the stability of the slurry through comparing with a traditional alkaline slurry (marked as slurry B, pH = 9.5), such as the pH value, particle size and zeta potential. Apart from this, the stability of the copper removal rate, dishing, erosion and surface roughness were also studied. All the results show that the stability of the novel low-pH alkaline slurry is better than the traditional alkaline slurry. The working-life of the novel low-pH alkaline slurry reaches 48 h. (semiconductor technology)

  2. Bone mineralisation in premature infants cannot be predicted from serum alkaline phosphatase or serum phosphate

    DEFF Research Database (Denmark)

    Faerk, J; Peitersen, Birgit; Petersen, S; Michaelsen, K F

    2002-01-01

    BACKGROUND: The bone mineral content of premature infants at term is lower than in mature infants at the same postconceptional age. Serum alkaline phosphatase and serum phosphate are often used as indicators of bone mineralisation. OBJECTIVE: To analyse the association between bone mineral content...... and serum alkaline phosphatase and serum phosphate. METHODS: Serum alkaline phosphatase and phosphate were measured at weekly intervals during admission in 108 premature infants of gestational age below 32 weeks (mean (SD) gestational age 29 (2) weeks; mean (SD) birth weight 1129 (279) g). Bone...... alkaline phosphatase (p = 0.8), peak serum alkaline phosphatase (p = 0.5), or mean serum phosphate (p = 0.2) at term. CONCLUSION:Routine measurements of serum alkaline phosphatase and serum phosphate are of no use in predicting bone mineralisation outcome in premature infants....

  3. A constructed alkaline consortium and its dynamics in treating alkaline black liquor with very high pollution load.

    Directory of Open Access Journals (Sweden)

    Chunyu Yang

    Full Text Available BACKGROUND: Paper pulp wastewater resulting from alkaline extraction of wheat straw, known as black liquor, is very difficult to be treated and causes serious environmental problems due to its high pH value and chemical oxygen demand (COD pollution load. Lignin, semicellulose and cellulose are the main contributors to the high COD values in black liquor. Very few microorganisms can survive in such harsh environments of the alkaline wheat straw black liquor. A naturally developed microbial community was found accidentally in a black liquor storing pool in a paper pulp mill of China. The community was effective in pH decreasing, color and COD removing from the high alkaline and high COD black liquor. FINDINGS: Thirty-eight strains of bacteria were isolated from the black liquor storing pool, and were grouped as eleven operational taxonomy units (OTUs using random amplified polymorphic DNA-PCR profiles (RAPD. Eleven representative strains of each OTU, which were identified as genera of Halomonas and Bacillus, were used to construct a consortium to treat black liquor with a high pH value of 11.0 and very high COD pollution load of 142,600 mg l(-1. After treatment by the constructed consortium, about 35.4% of color and 39,000 mg l(-1 (27.3% COD(cr were removed and the pH decreased to 7.8. 16S rRNA gene polymerase chain reaction denaturant gradient gel electrophoresis (PCR-DGGE and gas chromatography/mass spectrometry (GC/MS analysis suggested a two-stage treatment mechanism to elucidate the interspecies collaboration: Halomonas isolates were important in the first stage to produce organic acids that contributed to the pH decline, while Bacillus isolates were involved in the degradation of lignin derivatives in the second stage under lower pH conditions. CONCLUSIONS/SIGNIFICANCE: Tolerance to the high alkaline environment and good controllability of the simple consortium suggested that the constructed consortium has good potential for black liquor

  4. Dreams of a New Medium

    Directory of Open Access Journals (Sweden)

    Aden Evens

    2009-01-01

    Full Text Available Problematic at best, the desire for a transparent interface nevertheless drives much of digital culture and technology. But not the Web; or at least, not Web 1.0. Thoroughly commercialized, comfortably parsed into genres, serving billions of pages of predigested content to passive consumers, the World Wide Web as developed in the '90s unabashedly embraces its role as medium. While so many digital technologies work to hide their mediacy--drawing in the user with a total simulated sensorium, dematerializing the resistances of size and weight, untangling the knots of cables tying user to machine and machine to cubicle, minimizing the interface--Web 1.0 proudly clings to the browser as a glaring reminder of its medial character. While Web 2.0 has not forsaken the browser altogether, it nevertheless seems to offer a different sort of mediation. Arising alongside the atomization of browser functions, the ubiquitization of connectivity, and the coincidence of producer and user, Web 2.0 retains the form of a medium while reaching for the experiential logic of immediacy. This is not the immediacy of the transparent interface; rather, Web 2.0 effects an immediate relationship between the individual and culture. The interface does not disappear, but its mediacy is subsumed under the general form of cultural participation. Focusing on the "version upgrade" from Web 1.0 to 2.0, this essay will explore the implications for mediacy of this transition, noting that the fantasy of immediacy which drives Web 2.0 is layered and complex. The typical account of immediacy proposes to eliminate the interface and so construct a virtual reality (VR. But Web 2.0 mostly sidesteps the virtual, propelled instead by a fantasy of intuition in which the Web already knows what you want because it is you. Crucially, fantasies about the digital are effective: the computer's futurity inhabits our world, finding its expression in politics, advertising, budgeting, strategic planning

  5. Hydrothermal alkaline stability of bentonite barrier by concrete interstitial wastes

    International Nuclear Information System (INIS)

    At present, the main source of High Level radioactive Waste (HLW) is the electrical energy production during all the steps of developing. In almost all the countries with nuclear programs, the option for the final management of HLW is the Deep Geological Repository (DGR) based on the concept of multi barrier. According to this concept, the waste is isolated from biosphere by the interposition of confinement barriers. Two of the engineering barriers in the Spanish design of DGR in granitic rock are compacted bentonite and concrete. The bentonite barrier is the backfilling and sealing material for the repository gallery, because of its mechanical and physico-chemical properties. The main qualities of concrete as a component of a multi barrier system are its low permeability, mechanical resistance and chemical properties. With regard to chemical composition of concrete, the alkaline nature of cement pore water lowers the solubility of many radioactive elements. However, structural transformation in smectite, dissolution or precipitation of minerals and, consequently, changes in the bentonite properties could occurs in the alkaline conditions generated by the cement degradation. The main objective of the present work is to evaluate the effect of concrete in the stability of Spanish reference bentonite (La Serrata of Nijar, Almeria, Spain) in conditions similar to those estimated in a DGR in granitic rock. Because of the main role of bentonite barrier in the global performance of the repository, the present study is essential to guarantee its security. (Author)

  6. Digestibility Improvement of Sorted Waste with Alkaline Hydrothermai Pretreatment

    Institute of Scientific and Technical Information of China (English)

    WANG Hao; WANG Hongtao; LU Wenjing; ZHAO Yan

    2009-01-01

    The digestibility of sorted municipal solid waste (MSW) is often limited by the high content of structured green waste. The objectives of this study are to investigate the effect of alkaline hydrothermal pretreatment on the anaerobic digestion of sorted waste and to analyze the biogas production of different parts of the waste. The waste was hydrothermally pretreated in a dilute alkali solution. The hydrolysis product was then incubated in a 500 mL saline bottle to determine the biochemical methane potential (BMP) under mesophilic anaerobic conditions. The optimum hydrothermal condition was 170℃ at 4 g NaOH/100 g solid for one hour. The concentration of chemical oxygen demand (COD) was 13 936 mg/L and the methane yield was 164 mL/g volatile solid (VS) for 6 days incubation at the optimum conditions. The biogas production was increased more than 50% over the control, with the methane conversion ratio on a carbon basis enhanced to 30.6%. The organic part of the sorted waste was mainly kitchen garbage and leaves. Model kitchen garbage completely liquified at 130℃ for one hour had a methane yield of 276 mL/g VS. The alkali addition slightly enhanced the hydrolyzation rate and methane yield. The biogas potential of leaves was improved by pre-treatment at above 150℃ under alkaline conditions.

  7. Alkaline earths as main group reagents in molecular catalysis.

    Science.gov (United States)

    Hill, Michael S; Liptrot, David J; Weetman, Catherine

    2016-02-21

    The past decade has witnessed some remarkable advances in our appreciation of the structural and reaction chemistry of the heavier alkaline earth (Ae = Mg, Ca, Sr, Ba) elements. Derived from complexes of these metals in their immutable +2 oxidation state, a broad and widely applicable catalytic chemistry has also emerged, driven by considerations of cost and inherent low toxicity. The considerable adjustments incurred to ionic radius and resultant cation charge density also provide reactivity with significant mechanistic and kinetic variability as group 2 is descended. In an attempt to place these advances in the broader context of contemporary main group element chemistry, this review focusses on the developing state of the art in both multiple bond heterofunctionalisation and cross coupling catalysis. We review specific advances in alkene and alkyne hydroamination and hydrophosphination catalysis and related extensions of this reactivity that allow the synthesis of a wide variety of acyclic and heterocyclic small molecules. The use of heavier alkaline earth hydride derivatives as pre-catalysts and intermediates in multiple bond hydrogenation, hydrosilylation and hydroboration is also described along with the emergence of these and related reagents in a variety of dehydrocoupling processes that allow that facile catalytic construction of Si-C, Si-N and B-N bonds. PMID:26797470

  8. Neutralization potential as an assay of alkalinity of environmental solids

    International Nuclear Information System (INIS)

    The method to determine neutralizing equivalence of agricultural limestone has been applied to quantify the amount of bases present in a broad diversity of mineral materials, solid reagents, and products involved in environmental processes. The capacity to neutralize native or imposed acidity must be known in many processes in order to preserve near-neutral material. The standard method for assaying agricultural limestones was adapted to quantify native alkalinity in calcareous rocks exposed by coal surface mining. Data from these analyses continue to provide the surface mining industry and regulating agencies with a measure of the extent to which acidic mine drainage may be neutralized by the natural components of surrounding rock strata and disturbed materials. This approach to determine base content has also been applied to commercially available industrial byproducts added to soils or wastes. Kiln dust, fly ash, sludge, and other additives have been evaluated routinely to measure their alkalinity contribution and also batch-to-batch uniformity. The application of this technique to monitor amounts of reagents added to neutralize acid waste materials by adding alkalis is discussed. Use of this procedure to evaluate different materials is documented with exemplary data. Results of analyses of a broad variety of rock and soil materials, amended soils, soil additives or amendments, industrial waste byproducts, sludge, and treated wastes are presented. Utility of the procedure for routine quality control in soil treatment, amendment uniformity, and product analysis is discussed

  9. Enhanced Thermostability of a Fungal Alkaline Protease by Different Additives

    Directory of Open Access Journals (Sweden)

    Nilesh P. Nirmal

    2014-01-01

    Full Text Available A fungal strain (Conidiobolus brefeldianus MTCC 5184 isolated from plant detritus secreted a high activity alkaline protease. Thermostability studies of the fungal alkaline protease (FAP revealed that the protease is stable up to 50°C with 40% residual activity after one hour. Effect of various additives such as sugars, sugar alcohols, polyols, and salts, on the thermostability of FAP was evaluated. Among the additives tested, glycerol, mannitol, xylitol, sorbitol, and trehalose were found to be very effective in increasing the stability of FAP, which was found to be concentration dependent. Fivefold increase in residual activity of FAP was observed in the presence of trehalose (50% and sorbitol (50% at 50°C for 4 h, compared to FAP without additive. Other additives like calcium at 20 mM and 10–15% ammonium sulphate showed lower stability improvement than trehalose and sorbitol. NaCl, MgCl2, K2HPO4, and glycine were found to be poor stabilizers and showed only a marginal improvement. PEG 6000 did not show any increase in stability but was found to be slightly inhibitory.

  10. Evaluation of high solids alkaline pretreatment of rice straw.

    Science.gov (United States)

    Cheng, Yu-Shen; Zheng, Yi; Yu, Chao Wei; Dooley, Todd M; Jenkins, Bryan M; VanderGheynst, Jean S

    2010-11-01

    Fresh-harvested, air-dried rice straw was pretreated at a water content of 5 g H(2)O/g straw using sodium hydroxide (NaOH) and compared to pretreatment at 10 g H(2)O/g straw by hydrated lime (Ca(OH)(2)). Full factorial experiments including parallel wash-only treatments were completed with both sources of alkali. The experiments were designed to measure the effects of alkaline loading and pretreatment time on delignification and sugar yield upon enzymatic hydrolysis. Reaction temperature was held constant at 95 degrees C for lime pretreatment and 55 degrees C for NaOH pretreatment. The range of delignification was 13.1% to 27.0% for lime pretreatments and was 8.6% to 23.1% for NaOH pretreatments. Both alkaline loading and reaction time had significant positive effects (p lime-pretreated and unwashed biomass and were 142.3 mg/g dried biomass (39.2% conversion efficiency of total glucose) in NaOH-pretreated and unwashed biomass. PMID:20440580

  11. Proposal for Laser Cooling of Alkaline Earth Monoalkoxide Free Radicals

    Science.gov (United States)

    Baum, Louis; Kozyryev, Ivan; Matsuda, Kyle; Doyle, John M.

    2016-05-01

    Cold samples of polyatomic molecules will open new avenues in physics, chemistry, and quantum science. Non-diagonal Franck-Condon factors, technically challenging wavelengths, and the lack of strong electronic transitions inhibit direct laser cooling of nonlinear molecules. We identify a scheme for optical cycling in certain molecules with six or more atoms. Replacing hydrogen in alcohols with an alkaline earth metal (M) leads to alkaline earth monoalkoxide free radicals (MOR), which have favorable properties for laser cooling. M-O bond is very ionic, so the metal orbitals are slightly affected by the nature of R on the ligand. Diagonal Franck-Condon factors, laser accessible transitions, and a small hyperfine structure make MOR molecules suitable for laser cooling. We explore a scheme for optical cycling on the A - X transition of SrOCH3 . Molecules lost to dark vibrational states will be repumped on the B - X transition. Extension to larger species is possible through expansion of the R group since transitions involve the promotion of the metal-centered nonbonding valence electron. We will detail our estimations of the Franck-Condon factors, simulations of the cooling process and describe progress towards the Doppler cooling of MOR polyatomics.

  12. Alkaline volcanic rocks from the Columbia Hills, Gusev crater, Mars

    Science.gov (United States)

    McSween, H.Y.; Ruff, S.W.; Morris, R.V.; Bell, J.F., III; Herkenhoff, K.; Gellert, Ralf; Stockstill, K.R.; Tornabene, L.L.; Squyres, S. W.; Crisp, J.A.; Christensen, P.R.; McCoy, T.J.; Mittlefehldt, D. W.; Schmidt, M.

    2006-01-01

    Irvine, Backstay, and Wishstone are the type specimens for three classes of fine-grained or fragmental, relatively unaltered rocks with distinctive thermal emission spectra, found as float on the flanks of the Columbia Hills. Chemical analyses indicate that these rocks are mildly alkaline basalt, trachybasalt, and tephrite, respectively. Their mineralogy consists of Na- and K-rich feldspar(s), low- and high-Ca pyroxenes, ferroan olivine, Fe-Ti (and possibly Cr) oxides, phosphate, and possibly glass. The texture of Wishstone is consistent with a pyroclastic origin, whereas Irvine and Backstay are lavas or possibly dike rocks. Chemical compositions of these rocks plot on or near liquid lines of descent for most elements calculated for Adirondack class rocks (olivine-rich basalts from the Gusev plains) at various pressures from 0.1 to 1.0 GPa. We infer that Wishstone-, Backstay-, and Irvine-class magmas may have formed by fractionation of primitive, oxidized basaltic magma similar to Adirondack-class rocks. The compositions of all these rocks reveal that the Gusev magmatic province is alkaline, distinct from the subalkaline volcanic rocks thought to dominate most of the planet's surface. The fact that differentiated volcanic rocks were not encountered on the plains prior to ascending Husband Hill may suggest a local magma source for volcanism beneath Gusev crater. Copyright 2006 by the American Geophysical Union.

  13. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL; SEMIANNUAL

    International Nuclear Information System (INIS)

    This document summarizes progress on the Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period April 1, 2000 through September 30, 2000. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid will also be determined, as will the removal of arsenic, a known poison for NOX selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), First Energy Corporation, and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. This is the second reporting period for the subject Cooperative Agreement. During this period, the first of four short-term sorbent injection tests were conducted at the First Energy Bruce Mansfield Plant. This test determined the effectiveness of dolomite injection through out-of-service burners as a means of controlling sulfuric acid emissions from this unit. The tests showed that dolomite injection could achieve up to 95% sulfuric acid removal. Balance of plant impacts on furnace slagging and fouling, air heater fouling, ash loss-on-ignition, and the flue gas desulfurization system were also determined. These results are presented and discussed in this report

  14. 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.

  15. Potential control flotation of galena in strong alkaline media

    Institute of Scientific and Technical Information of China (English)

    顾帼华; 胡岳华; 邱冠周; 王晖; 王淀佐

    2002-01-01

    The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below 0.17 V, the oxidation products of galena are elemental sulfur and HPbO-2. Elemental sulfur was present on the mineral surface in excess of oxidized lead species due to dissolution of HPbO-2, which is beneficial to the flotation of galena. Under the same conditions, sphalerite and pyrite were depressed as a result of significant surface oxidation. Diethyldithiocarbamate (DDTC) was found to be the most suitable collector for galena flotation in strongly alkaline media. The very potential produced hydrophobic PbD2-the surface reaction product of DDTC with galena, is 0 to 0.2 V. Meantime DDTC can depress the surface over-oxidation of galena. Investigations also indicate that, in the range of -0.9 V to 0.6 V, hydrophobic PbD2 can be firmly adsorbed on galena.

  16. Combined alkaline and ultrasonic pretreatment of sludge before aerobic digestion

    Institute of Scientific and Technical Information of China (English)

    JIN Yiying; LI Huan; MAHAR Rasool Bux; WANG Zhiyu; NIE Yongfeng

    2009-01-01

    Alkaline and ultrasonic sludge disintegration can both be used as pretreatments of waste activated sludge (WAS) for improving the subsequent anaerobic or aerobic digestion. The pretreatment has been carried out using different combination of these two methods in this study. The effect was evaluated based on the quantity of soluble chemical oxygen demand (SCOD) in the pretreated sludge as well as the degradation of organic matter in the following aerobic digestion. For WAS samples with combined pretreatment, the released COD was in high level than those with ultrasonic or alkaline treatment. When combined with the same ultrasonic treatment, NaOH treatment resulted in more solubilization of WAS than Ca(OH)2. For combined NaOH and ultrasonic treatments with different sequences, the released COD were in the order: simultaneous treatment > ultrasonic treatment following NaOH treatment > NaOH treatment following ultrasonic treatment. For simultaneous treatment, low NaOH dosage (100 g/kg dry solid), short duration (30 min) of NaOH treatment, and low ultrasonic specific energy (7 500 kJ/kg dry solid) were beneficial for sludge disintegration. Using combined NaOH and ultrasonic pretreatment with the optimium parameters, the degradation efficiency of organic matter was increased from 38.0% to 50.7%, which is much higher than with ultrasonic (42.5%) or with NaOH pretreatment (43.5%) in the subsequent aerobic digestion at the same retention time.

  17. Synthesis of Zeolites by Alkaline Activation of Fly Ash

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In terms of mineral transformation, and chemical composition of acid-soluble component as a function of reaction time, the effect of alkaline solution on zeolite-like fly ash was studied by employing fly ash and NaOH solution as starting materials. When fly ash and 1€? 0mol/L NaOH solution were processed at 100℃ for 24h with 1:10 W/S rat io in a relatively closed system, powder XRD patterns of resulting pro ducts indicated the formation of various zeolites. Zeolite P crystalli zed early at low alkaline concentration, which was replaced then by ze olites X and A. At high concentration, hydroxy sodalite was the only n ew phase. Quartz, in fly ash and NaOH solution system, gradually disso lved, and mullite, however, remained stable. It was concluded that, wi th Al/Si and Na/Si finally reaching equilibrium in molar ratio, compos ition of starting mixtures affects the crystallization of zeolite from fly ash.

  18. Processes determining the marine alkalinity and carbonate saturation distributions

    Directory of Open Access Journals (Sweden)

    B. R. Carter

    2014-07-01

    Full Text Available We introduce a composite tracer, Alk*, that has a global distribution primarily determined by CaCO3 precipitation and dissolution. Alk* also highlights riverine alkalinity plumes that are due to dissolved calcium carbonate from land. We estimate the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk* in the Arctic surface and particularly near river mouths. Strong net carbonate precipitation lowers basin mean Indian and Atlantic Alk*, while upwelling of dissolved CaCO3 rich deep waters elevates Northern Pacific and Southern Ocean Alk*. We use the Alk* distribution to estimate the carbonate saturation variability resulting from CaCO3 cycling and other processes. We show regional variations in surface carbonate saturation are due to temperature changes driving CO2 fluxes and, to a lesser extent, freshwater cycling. Calcium carbonate cycling plays a tertiary role. Monitoring the Alk* distribution would allow us to isolate the impact of acidification on biological calcification and remineralization.

  19. Recent advances in Rydberg physics using alkaline-earth atoms

    Science.gov (United States)

    Dunning, F. B.; Killian, T. C.; Yoshida, S.; Burgdörfer, J.

    2016-06-01

    In this brief review, the opportunities that the alkaline-earth elements offer for studying new aspects of Rydberg physics are discussed. For example, the bosonic alkaline-earth isotopes have zero nuclear spin which eliminates many of the complexities present in alkali Rydberg atoms, permitting simpler and more direct comparison between theory and experiment. The presence of two valence electrons allows the production of singlet and triplet Rydberg states that can exhibit a variety of attractive or repulsive interactions. The availability of weak intercombination lines is advantageous for laser cooling and for applications such as Rydberg dressing. Excitation of one electron to a Rydberg state leaves behind an optically active core ion allowing, for high-L states, the optical imaging of Rydberg atoms and their (spatial) manipulation using light scattering. The second valence electron offers the possibility of engineering long-lived doubly excited states such as planetary atoms. Recent advances in both theory and experiment are highlighted together with a number of possible directions for the future.

  20. ALKALINE PEROXIDE MECHANICAL PULPING OF NOVEL BRAZILIAN EUCALYPTUS HYBRIDS

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho dos Santos Muguet,

    2012-07-01

    Full Text Available Eucalyptus wood is among the most important biomass resource in the world. Wood mechanical defibration and fibrillation are energy-intensive processes utilized not only to produce pulp for papermaking, but also to produce reinforcement fibers for biocomposites, nanocellulose, or pretreat lignocellulosic material for biofuels production. The structural features of different Eucalyptus hybrids affecting the refining energy consumption and produced fiber furnish properties were evaluated. The defibration and fiber development were performed using an alkaline peroxide mechanical pulping (APMP process, which included chelation followed by an alkaline peroxide treatment prior to wood chip defibration. Despite the similar wood densities and chemical compositions of different Eucalyptus hybrids, there was a clear difference in the extent of defibration and fibrillation among the hybrids. The high energy consumption was related to a high amount of guaiacyl lignin. This observation is of major importance when considering the optimal wood hybrids for mechanical wood defibration and for understanding the fundamental phenomena taking place in chemi-mechanical defibration of wood.

  1. Transpassive electrodissolution of depleted uranium in alkaline electrolytes

    International Nuclear Information System (INIS)

    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 UO3·2H2O, 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

  2. [DNA degradation during standard alkaline of thermal denaturation].

    Science.gov (United States)

    Drozhdeniuk, A P; Sulimova, G E; Vaniushin, B F

    1976-01-01

    Essential degradation 8 DNA (up to 10 per cent) with liberation of acid-soluble fragments takes place on the standard alkaline (0,01 M sodium phosphate, pH 12, 60 degrees, 15 min) or thermal (0.06 M sodium phosphate buffer, pH 6.8, 102 degrees C, 15 min) denaturation. This degradation is more or less selective: fraction of low molecular weight fragments, isolated by hydroxyapatite cromatography and eluted by 0.06 M sodium phosphate buffer, pH 6.8 is rich in adenine and thymine and contains about 2 times less 5-methylcytosine than the total wheat germ DNA. The degree of degradation of DNA on thermal denaturation is higher than on alkaline degradation. Therefore while studying reassociation of various DNA, one and the same standard method of DNA denaturation should be used. Besides, both the level of DNA degradation and the nature of the resulting products (fragments) should be taken into account. PMID:999984

  3. Nb-TiO{sub 2} supported platinum nanocatalyst for oxygen reduction reaction in alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Elezovic, N.R., E-mail: nelezovic@tmf.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, Belgrade (Serbia); Babic, B.M. [Vinca Institute of Nuclear Sciences, Belgrade (Serbia); Radmilovic, V.R. [National Center for Electron Microscopy, LBNL University of California, Berkely (United States); Vracar, Lj.M.; Krstajic, N.V. [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia)

    2011-10-30

    Highlights: > Nb doped TiO{sub 2} catalyst support was successfully synthesized. > Synthesized support surface area was much higher comparing with sub-stoichiometric titanium oxides as supporting material. > The Nb-TiO{sub 2} supported Pt catalyst was successfully prepared and characterized by TEM technique. > Nb doped TiO{sub 2} support seems to be more suitable than carbon based support. > The change in the rate-determining step was proposed for reaction mechanism explanation. - Abstract: Platinum based nanocatalyst at home made Nb-TiO{sub 2} support was synthesized and characterized as the catalyst for oxygen reduction reaction in 0.1 mol dm{sup -3} NaOH, at 25 deg. C. Nb doped TiO{sub 2} catalyst support, containing 5% of Nb, has been synthesized by modified acid-catalyzed sol-gel procedure in non-aqueous medium. BET and X-ray diffraction (XRD) techniques were applied for characterization of synthesized supporting material. XRD analysis revealed only presence of anatase TiO{sub 2} phase in synthesized support powder. Existence of any peaks belonging to Nb compounds has not been observed, indicating Nb incorporated into the lattice. Nb-TiO{sub 2} supported Pt nanocatalyst synthesized, using borohydride reduction method, was characterized by TEM and HRTEM techniques. Platinum nanoparticles distribution, over Nb doped TiO{sub 2} support, was quite homogenous. Mean particle size of about 4 nm was found with no pronounced particle agglomeration. Electrochemical techniques: cyclic voltammetry and linear sweep voltammetry at rotating disc electrode were applied in order to study kinetics and estimate catalytic activity of this new catalyst for the oxygen reduction reaction in alkaline solution. Two different Tafel slopes were found: one close to -90 mV dec{sup -1} in low current density region and other approximately -200 mV dec{sup -1} in high current density region, which is in good accordance with literature results for oxygen reduction at Pt single crystals, as

  4. Identification of Listeria monocytogenes Genes Involved in Salt and Alkaline-pH Tolerance

    OpenAIRE

    Gardan, Rozenn; Cossart, Pascale; Labadie, Jean

    2003-01-01

    The capacity of Listeria monocytogenes to tolerate salt and alkaline stresses is of particular importance, as this pathogen is often exposed to such environments during food processing and food preservation. We screened a library of Tn917-lacZ insertional mutants in order to identify genes involved in salt and/or alkaline tolerance. We isolated six mutants sensitive to salt stress and 12 mutants sensitive to salt and alkaline stresses. The position of the insertion of the transposon was locat...

  5. Trichoderma harzianum transformant has high extracellular alkaline proteinase expression during specific mycoparasitic interactions

    Directory of Open Access Journals (Sweden)

    Goldman Maria Helena S.

    1998-01-01

    Full Text Available The mycoparasite Trichoderma harzianum produces an alkaline proteinase that may be specifically involved in mycoparasitism. We have constructed transformant strains of this fungus that overexpress this alkaline proteinase. Some of the transformants were assessed for alkaline proteinase activity, and those with higher activity than the wild type were selected for further studies. One of these transformant strains produced an elevated and constitutive pbr1 mRNA level during mycoparasitic interactions with Rhizoctonia solani.

  6. Decrease in dynamic viscosity and average molecular weight of alginate from Laminaria digitata during alkaline extraction

    OpenAIRE

    Vauchel, Peggy; Arhaliass, Abdellah; Legrand, Jack; Kaas, Raymond; Baron, Regis

    2008-01-01

    Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1-4 h in duration were determined, i...

  7. Geology and petrology of alkaline Massif from Ilha de Vitoria, Sao Paulo State

    International Nuclear Information System (INIS)

    Geological and petrological studies of the Vitoria Island Alkaline Complex, State of Sao Paulo, have been carried out by means of photo interpretation; field work, thin section studies, whole-rock chemical analysis, x-ray diffractometry, EPMA mineral analysis, and K-Ar and Rb-Sr dating. Radiometric dating indicates a late Cretaceous age for the Vitoria Island Alkaline Complex, which is concordant with the ages of other neighbouring alkaline bodies. (author)

  8. Hydrolysis of pyridoxal-5'-phosphate in plasma in conditions with raised alkaline phosphate.

    OpenAIRE

    Anderson, B B; O'Brien, H.; Griffin, G E; Mollin, D. L.

    1980-01-01

    Hydrolysis of pyridoxal phosphate in plasma was demonstrated in patients with liver disease and other conditions with raised alkaline phosphatase, and this usually closely paralleled the alkaline phosphatase level, whether of liver or bone origin. The endogenous plasma pyridoxal phosphate was inversely related to the alkaline phosphatase, and plasma hydrolysis of pyridoxal phosphate may at least in part be responsible. Very large doses of vitamin B6 may be necessary to compensate for this hyd...

  9. Studies in medium energy physics

    International Nuclear Information System (INIS)

    This document constitutes the (1991--1992) technical progress report and continuation proposal for the ongoing medium energy nuclear physics research program supported by the US Department of Energy through special Research Grant DE-FG05-88ER40444. The experiments discussed are conducted at the Los Alamos National Laboratory's (LANL) Clinton P. Anderson Meson Physics Facility (LAMPF) and the Alternating Gradient Synchrotron (AGS) facility of the Brookhaven National Laboratory (BNL). The overall motivation for the work discussed in this document is driven by three main objectives: (1) provide hadron-nucleon and hadron-nucleus scattering data which serve to facilitate the study of effective two-body interactions, test (and possibly determine) nuclear structure, and help study reaction mechanisms and dynamics; (2) provide unique, first-of-a-kind ''exploratory'' hadron-nucleus scattering data in the hope that such data will lead to discovery of new phenomena and new physics; and (3) perform precision tests of fundamental interactions, such as rare decay searches, whose observation would imply fundamental new physics

  10. The interstellar medium in galaxies

    CERN Document Server

    1997-01-01

    It has been more than five decades ago that Henk van de Hulst predicted the observability of the 21-cm line of neutral hydrogen (HI ). Since then use of the 21-cm line has greatly improved our knowledge in many fields and has been used for galactic structure studies, studies of the interstellar medium (ISM) in the Milky Way and other galaxies, studies of the mass distribution of the Milky Way and other galaxies, studies of spiral struc­ ture, studies of high velocity gas in the Milky Way and other galaxies, for measuring distances using the Tully-Fisher relation etc. Regarding studies of the ISM, there have been a number of instrumen­ tal developments over the past decade: large CCD's became available on optical telescopes, radio synthesis offered sensitive imaging capabilities, not only in the classical 21-cm HI line but also in the mm-transitions of CO and other molecules, and X-ray imaging capabilities became available to measure the hot component of the ISM. These developments meant that Milky Way was n...

  11. Enriching the hot circumgalactic medium

    CERN Document Server

    Crain, Robert A; Schaye, Joop; Frenk, Carlos S; Theuns, Tom

    2013-01-01

    Models of galaxy formation in a CDM universe predict that massive galaxies are surrounded by a hot, quasi-hydrostatic circumgalactic corona of slowly cooling gas, predominantly accreted from the IGM. This prediction is borne out by the cosmological hydrodynamical simulations of Crain et al., which reproduce scaling relations between the X-ray and optical properties of nearby disc galaxies. Such coronae are metal poor, but observations of the X-ray emitting circumgalactic medium (CGM) of local galaxies typically indicate enrichment to near-solar iron abundance, potentially signalling a shortcoming in galaxy formation models. We show here that, while the hot CGM of galaxies formed in the simulations is metal poor in a mass-weighted sense, its X-ray luminosity-weighted metallicity is often close to solar. This bias arises because the soft X-ray emissivity of a typical 0.1 keV corona is dominated by collisionally-excited metal ions that are synthesised in stars and recycled into the hot CGM. We find that these me...

  12. Turbulence in the Intergalactic Medium

    CERN Document Server

    Evoli, Carmelo

    2011-01-01

    We study supernova-driven galactic outflows as a mechanism for injecting turbulence in the intergalactic medium (IGM) far from galaxies. To this aim we follow the evolution of a 10^13 Msun galaxy along its merger tree, with carefully calibrated prescriptions for star formation and wind efficiencies. At z~3 the majority of the bubbles around galaxies are old (ages >1Gyr), i.e. they contain metals expelled by their progenitors at earlier times; their filling factor increases with time reaching about 10% at z<2. The energy deposited by these expanding shocks in the IGM is predominantly in kinetic form (mean energy density of 1 \\mu eV cm^-3, about 2-3 x the thermal one), which is rapidly converted in disordered motions by instabilities, finally resulting in a fully developed turbulent spectrum whose evolution is followed through a spectral transfer function approach. The derived mean IGM turbulent Doppler parameter, b_t, peaks at z~1 at about 1.5 km/s with maximum b_t = 25 km/s. The shape of the b_t distributi...

  13. Eco-physiological Characteristics of Alfalfa Seedlings in Response to Various Mixed Salt-alkaline Stresses

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Soil salinization and alkalization frequently co-occur in nature, but little is known about the mixed effects of salt-alkaline stresses on plants. An experiment with mixed salts (NaCl, Na2SO4, NaHCO3 and Na2CO3) and 30 salt-alkaline combinations(salinity 24-120 mmol/L and pH 7.03-10.32) treating Medicago sativa seedlings was conducted. The results demonstrated that salinity and alkalinity significantly affected total biomass and biomass components of seedlings. There were interactive effects of salt composition and concentration on biomass (P ≤ 0.001). The interactions between salinity and alkalinity stresses led to changes in the root activity along the salinity gradient (P ≤ 0.001). The effects of alkalinity on seedling survival rate were more significant than those of salinity, and the seedlings demonstrated some physiological responses(leaf electrolyte leakage rate and proline content) in order to adapt to mixed salt-alkaline stresses. It was concluded that the mixed salt-alkaline stresses, which differ from either salt or alkali stress, emphasize the significant interaction between salt concentration (salinity) and salt component (alkalinity). Further, the effects of the interaction between high alkalinity and salinity are more severe than those of either salt or alkali stress, and such a cooperative interaction results in more sensitive responses of ecological and physiological characteristics in plants.

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

    International Nuclear Information System (INIS)

    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

  15. Medium-induced multi-photon radiation

    OpenAIRE

    MA, Hao; Salgado, Carlos A.; Tywoniuk, Konrad

    2011-01-01

    We study the spectrum of multi-photon radiation off a fast quark in medium in the BDMPS/ASW approach. We reproduce the medium-induced one-photon radiation spectrum in dipole approximation, and go on to calculate the two-photon radiation in the Moli\\`{e}re limit. We find that in this limit the LPM effect holds for medium-induced two-photon ladder emission.

  16. Medium-induced multi-photon radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ma Hao; Salgado, Carlos A [Departamento de Fisica de PartIculas, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Tywoniuk, Konrad [Lund University (Sweden)

    2011-01-01

    We study the spectrum of multi-photon radiation off a fast quark in medium in the BDMPS/ASW approach. We reproduce the medium-induced one-photon radiation spectrum in dipole approximation, and go on to calculate the two-photon radiation in the Moliere limit. We find that in this limit the LPM effect holds for medium-induced two-photon ladder emission.

  17. Selective medium for isolation of Actinobacillus actinomycetemcomitans.

    OpenAIRE

    Slots, J

    1982-01-01

    A selective medium, TSBV (tryptic soy-serum-bacitracin-vancomycin) agar, was developed for the isolation of Actinobacillus actinomycetemcomitans, TSBV agar contained (per liter) 40 g of tryptic soy agar, 1 g of yeast extract, 100 ml of horse serum. 75 mg of bacitracin, and 5 mg of vancomycin. The TSBV medium suppressed most oral species and permitted significantly higher recovery of A. actinomycetemcomitans than nonselective blood agar medium. The distinct colonial morphology and positive cat...

  18. Molecular collisions in the interstellar medium.

    OpenAIRE

    Flower, D

    2007-01-01

    In the interstellar medium - the space between the stars in galaxies - new stars are born from material that is replenished by the debris ejected by stars when they die. This book is a comprehensive manual for studying the collisional and radiative processes observed in the interstellar medium. This second edition has been thoroughly updated and extended to cover related topics in radiation theory. It considers the chemistry of the interstellar medium both at the present epoch and in the earl...

  19. Pion structure function in nuclear medium

    OpenAIRE

    Suzuki, Katsuhiko

    1995-01-01

    We study the pion structure function in nuclear medium using the Nambu and Jona-Lasinio model, and its implication for the nuclear pion enhancement of the sea quark distribution in nuclei. By using the operator product expansion, medium effect of the nuclear matter is incorporated in calculations of the twist-2 operators. We find density dependence of the pion structure function is rather weak around the nuclear matter density. We also discuss how the medium modification of the pion structure...

  20. Chemically defined medium and Caenorhabditis elegans

    Science.gov (United States)

    Szewczyk, Nathaniel J.; Kozak, Elena; Conley, Catharine A.

    2003-01-01

    BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.