bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of the exchange between battery‐active manganese dioxides and manganese(II) ions in aqueous solution
Authors: Rophael Magdy W. , Malati Mounir A. 
Published: July 2010

AbstractThe initial rate and the extent of exchange between 56Mn‐labelled dioxides and 0.1M MnSO4 solution at 25°C and pH 5.4 were found to increase in the series: β‐MoO2 (R4), <γ‐MnO2 (R2), < ϵ‐MnO2. The rate of exchange between R2 and 0.1M MnSO4 solution at pH 2.0 was higher than the corresponding results at pH 5.4 but the results were similar at the two pH values when R2 was washed with dilute acid (pH 2.0) prior to the exchange at pH 2.0. The results of the exchange for the size fraction −120 to + 300 mesh of R2 were similar to those for the unsieved R2 under the same conditions. When either R2 or R4 were partially reduced with N2H4·H2O solution prior to the exchange, the results were appreciably higher than those obtained for the unreduced solids—especially in the case of R2. When different concentrations of Mn(NO3)2 solution were used with R2, the percentage exchange increased to a small extent as the concentration increased ten‐fold. The variation of the solid: solution ratio had a minor effect on the extent of exchange between R2 and 0.1M MnSO4 solution.
Adaptation of the liquid chromatograph as a micro‐reactor; immobilised lactase kinetics
Authors: Melton H. Rodger , Bailey David C. , Langer Stanley H. 
Published: July 2010

AbstractA catalytic, micro‐reactor system has been developed using a modified liquid chromatograph with an ultraviolet spectrophotometer detector. The continuous flow, micro‐reactor method has been adapted to the measurement of the activity of enzyme catalysts immobilised on porous glass beads. The system offers advantages over other systems in terms of convenience and provisions for steady‐state analysis and control. The speed and ease of obtaining reproducible data make it feasible to study the efficacy of immobilisation techniques systematically and to explore liquid chromatographic reactor methods further. The kinetic data obtained were compatible with those found with other methods for the hydrolysis of o‐nitrophenyl‐β‐D‐galactopyranoside with immobilised lactase from the fungus Aspergillus niger.
Conversion of waste plastics to single‐cell protein by means of pyrolysis followed by fermentation
Authors: Karthigesan Jeevajothy , Brown Bernard S. 
Published: July 2010

AbstractWaste plastics (e.g. polyethylene, polystyrene and polypropylene) have been converted to single‐cell protein using pyrolysis followed by fermentation. Conversion efficiencies of plastics to pyrolysate were 75–90% for polyethylene, 10–56% for polystyrene and 40–50% for polypropylene. Unpyrolysed residues were formed with polystyrene (6–14%) and polypropylene (14–30%), but not with polyethylene. Polyvinyl chloride produced hydrogen chloride fumes, together with 33–39% unpyrolysed residue, no fermentable pyrolysis products being formed. Polyethylene pyrolysate was fermented by the yeast, Candida tropicalis. Batch fermentation was carried out at 31°C and pH 5.5 on polyethylene pyrolysate in shaken flasks (100 cm3 culture) and in an aerated fermenter (500 cm3 culture). Maximum growth rate was 0.168 h−1, cell yield was 0.47 ± 0.02 g g−1 pyrolysate used (n = 3) and doubling time was 4–5 h, after 72 h growth on 1.0g pyrolysate 100 cm−3 culture. Continuous culture (dilution rate 0.10 h−1) gave a dry cell yield of 0.39 g g−1 pyrolysate utilised. Utilisation of pyrolysate was 49.0% in batch culture and 33.0% in continuous culture. The efficiency of conversion of polyethylene to biomass was 34–42% in batch culture. Emulsification and pristane‐solubilisation were studied as a means of dispersing waxy pyrolysates in culture media. Pristane did not support growth whereas the emulsifier [lecithin, Tween 85 and sodium glycocholate (1:2:2 by weight)] could support up to 27% of the growth observed on polyethylene pyrolysate. Although growth would occur without either emulsifier or pristane, use of pristane increased both dry cell yield (g g−1 pyrolysate used) and pyrolysate utilisation by 1.3 times in flask cultures. Crude protein content of cells cultured on polyethylene pyrolysate was 46.7 ± 2.4% (n = 3) for batch culture cells, and 43.8 ± 0.3% (n = 4) for continuous culture cells. The true protein content of Candida cells was about 17%. The protein had a favourable nutritional quality as judged by in‐vitro chemical tests.
Studies on the dehydrocyclisation of n‐octane and gasoline over chromia—alumina—potassium oxide catalyst
Authors: Hassan Shawky M. , Abdou Ismil K. , Roushdi Mohamed I. , Elkadi Gamal M. 
Published: July 2010

AbstractA non‐acidic chromia‐alumina‐potassium oxide catalyst has been prepared which possesses high thermal stability and stable dehydrocyclisation activity for n‐octane and gasoline. Thermal sintering of the catalyst greatly influences its selectivity. The effect of reaction temperature and space velocity on the product distribution has been studied. At optimum conditions, about 90% (w/w) of n‐octane is converted into aromatics, of which 94% are ethylbenzene and o‐xylene. Of the gasoline fraction (50–130°C), about 75% (w/w) has been converted into aromatics. Octenes and C8‐alkylcyclohexanes detected after dehydrocyclisation of n‐octane are not intermediates in the reaction.
Distribution of trace metals in petroleum and its heavy refinery products
Authors: Abu‐Elgheit Mohamed A. , Elkholy Ibrahim S. , Barakat Assem O. 
Published: July 2010

AbstractThe distribution of trace metals between crude petroleum and its heavy products has been studied by emission spectrography. The highest concentration of V, Ni, Sb and Mg was associated with the asphaltic fraction. A correlation has been established between the V/Ni, V/Sb and Ni/Sb indices and the geologic age of petroleum. Examination of gas and diesel oils for suitability as catalytic cracking feedstocks has been made on the basis of their Ni equivalent. Lubricating oil was found to retain little or no trace metals from the parent crude oil. The relatively high V content of fuel oil can affect refinery equipment, distillation units and linings of industrial furnaces. Other trace metals are non‐destructive or only slightly destructive.
Liquid‐liquid equilibria for toluene‐heptane‐N‐methyl pyrrolidone and benzene‐heptane solvents
Authors: Nagpal Jag M. , Rawat Bachan S. 
Published: July 2010

AbstractThe liquid‐liquid equilibria for toluene‐n‐heptane‐N‐methyl pyrrolidone containing 10 and 20% water at 298 and 313 K, and of benzene‐n‐heptane with N‐methyl pyrrolidone‐ethylene glycol and γ‐butyrolactone‐ethylene glycol, which is a new solvent combination, have been determined at 303 K.
Biosynthesis of carbomycin, its extraction, purification and mode of action on Bacillus subtilis NRRL B‐543
Authors: Baghlaf A. O. , Abou‐Zeid A. Z. A. , El‐Diwzny A. I. 
Published: July 2010

AbstractA fermentation medium containing (g dm−3)—glucose, 10.0; soyabean meal, 10.0; NaCl, 5.0 and CaCO3, 1.0 in distilled water—was used in the biosynthesis of the macrolide antibiotic carbomycin. Maximum yield of carbomycin was obtained after 120 h fermentation. Carbomycin was extracted by different organic solvents adjusted to different pH values. Extraction of the antibiotic was possible when the pH of the fermentation broth was neutral (6.5–7.5) with all organic acids used, but the most efficient organic solvent suitable for extraction of carbomycin was chloroform at a pH of 6.5. Further purification was carried out by preparative thin layer chromatography. The most efficient separation into carbomycin A and carbomycin B was obtained using a solvent system of ethanol‐hexane‐water [90:10:0.15 (v/v)]. Carbomycin inhibited the biosynthesis of the anabolising cellular constituents phosphoprotein, ribonucleic and deoxyribonucleic acids in Bacillus subtilis NRRL B‐543.
Experimental examination of the room temperature hydrodynamics and electrochemical current‐voltage behaviour of the Bi‐terminated vibrating wire electrode
Authors: Moorhead Edward D. , Bhat Gajanana A. , Stephens Michael M. 
Published: July 2010

AbstractAn experimental study was made of the room temperature hydrodynamics and current‐voltage (I‐V) behaviour of a bi‐terminated transverse oscillating resonant electrode using an adaptation of the electromagnetically‐driven vibrating wire technique recently developed for precise viscosity measurements of cryogenic fluids. For argon, nitrogen, as well as dilute electrolytes, the shapes of the in‐phase and quadrature resonance lines agreed with lines obtained by computer simulation. Although such peaks exhibited shorter heights than predicted (probably due to dispersion or some energy loss to the end terminations), observed peak areas agreed with theory. Use of either 50‐μm diameter platinum or tungsten wires as working electrodes in three‐electrode voltammetry yielded quite well‐defined I‐V curves for reduction of dilute ferricyanide and iodate as test systems, with Fe(CN)6−3 exhibiting near‐Nernstian reversibility at the tungsten wire. Well‐shaped I‐V curves were also obtained for lead (II) reduction on oxide‐free platinum. Resonant platinum wires clad with lead films produced by controlled potential deposition yielded, as expected, an advantageous negative shift in potential for H+ reduction. Because the mechanical properties of soft or low tensile strength metals deny their direct use as resonant electrodes, clad wires, on the other hand, should enable electrochemical, corrosion, and surface studies of such materials to be accomplished under rather precisely controlled conditions.
The pyrolysis of propane. II. Effect of hydrogen sulphide
Authors: Trimm David L. , Turner Christopher J. 
Published: July 2010

AbstractHydrogen sulphide has been found to have a significant effect on the rate of carbon formation during the pyrolysis of propane. Studies have been carried out to measure carbon formation on pre‐sulphided foils of nickel, copper, iron and stainless steel, and to measure carbon formation on the metals from a mixture of propane and hydrogen sulphide. No changes could be detected in the gaseous or liquid products of pyrolysis in the presence of sulphides, but carbon formation was either inhibited or accelerated. The formation of stable metal sulphides inhibited carbon formation. The formation and subsequent decomposition of metal sulphides accelerated carbon formation.
Synthesis of antimicrobial heteroaryl‐substituted‐1,2,3‐triazolines via the reaction of diazomethane with anils and mixed azines of thiophenealdehyde and/or isatin
Authors: Youssef Mohamed S. K. 
Published: July 2010

AbstractDiazomethane was reacted with nitro‐substituted anils of thiophenealdehyde and/or isatin and with some unsymmetric azines. 1,2,3‐Triazolines were obtained in all cases. Product constitution is discussed. Some of these were found to inhibit the development of a range of Gram‐positive and Gram‐negative bacteria.
Adsorption of ionic and non‐ionic surfactants by wool charring waste
Authors: Perineau Francis , Gaset Antoine 
Published: July 2010

AbstractThe effect of pH and temperature on the adsorption of anionic, cationic, and non‐ionic surfactants on wool charring waste has been investigated in order to assess the optimum conditions of substrate use in water pollution control. The analysis of adsorption kinetics in aqueous media and in water‐alcohol mixtures, allowed different adsorption mechanisms to be characterised. Plots of the amount of surfactant adsorbed against the square root of time provided information on the diffusion processes. The effect of the chain length on the adsorption of alkylsulphates on wool charring waste corroborated the importance of hydrophobic interactions.
Synthesis of 5‐hydroxymethyl‐2‐furancarboxaldehyde catalysed by cationic exchange resins. Part 1. Choice of the catalyst and the characteristics of the reaction medium
Authors: Mercadier Daniel , Rigal Luc , Gaset Antoine , Gorrichon Jean‐Pierre 
Published: July 2010

AbstractIn this preliminary study, it was shown that strong acid ion exchange resins allowed the dehydration of D‐fructose to 5‐hydroxymethyl‐2‐furancarboxaldehyde at mild temperatures and pressures. Evidence was given that the use of a solvent (i.e. methyl isobutylketone) with high extracting power toward the obtained compound improved the yield of this reaction. In order to take into account the treatment of aqueous solutions of sugars as well as the peculiar use of ion exchange resins, particularly a good hydration mode, a water:solvent ratio of 1:9 was chosen. These conditions were shown to lead to satisfactory yields and conversion rates.
A theoretical analysis of the deactivation of an immobilised enzyme in multi‐enzyme reactions in fixed‐bed and fluid‐bed reactors
Authors: Sadana Ajit 
Published: July 2010

AbstractThe effect of time‐averaging on the selectivity to an intermediate R (yR) and the yield to product S (yR) in a consecutive reaction A→R→S, occurring in a deactivating fixed‐bed reactor, has been examined. Time‐averaging smooths the selectivity and increases the yield for high values of the deactivation (λ) and reaction (δ) parameters. The kinetics and dynamics of yR and yS in a deactivating steady‐state fluid‐bed reactor were also examined. Both non‐selective and selective deactivation are considered. The practical implications of the development are considered in terms of an example, in which the values chosen for parameters are arbitrary though reasonable with respect to experimental values.
Ternary phase equilibrium studies of the system: Tetrahydrofuran‐water‐alcohols
Authors: Patel Amrit N. 
Published: July 2010

AbstractTernary phase equilibrium data for tetrahydrofuran (THF) with water and butan‐1‐ol, 2‐methylpropan‐1‐ol, pentan‐1‐ol, cyclohexan‐1‐ol and benzyl alcohol are presented and used to evaluate the possibility of employing the distribution of THF between water and these alcohols as a means of separation of THF from aqueous solutions. The tie‐line data for the systems have been correlated and the plait‐points have been located.
Thermal characteristics of rice hulls
Authors: Hamad M. A. 
Published: July 2010

AbstractEvaluation of the thermal characteristics of rice hulls is described. Decomposition was negligible below 200°C, but on heating above 200°C, the amount of volatile matter evolved increased steadily with increasing temperature up to 450°C, where > 90 % of the total volatile matter was separated. Decomposition is rapid and is temperature dependent. The effect of temperature on the composition of the residues is also described. The carbon content of the residues increased while the oxygen and hydrogen content decreased sharply when the temperature of pyrolysis was increased.
Semiconductor‐electrochemical aspects of bacterial leaching. Part 2. Survey of rate‐controlling sulphide properties
Authors: Tributsch H. , Bennett J. C. 
Published: July 2010

AbstractSixteen metal sulphides with widely differing solid state, chemical and electrochemical properties have been investigated with respect to their suitability as an energy source for Thiobacillus ferrooxidans. The most critical rate‐determining parameter for bacterial oxidation (in the absence of any electron acceptors, e.g. Fe3+) was the solubility product of the sulphide. Deviations from the systematic dependence are, however, observed when a large concentration of the holes are present in the semiconducting sulphide (p‐type conduction), or when holes are generated through electron extraction from the sulphide surface (e.g. by Fe3+). The experimental results are consistent with a mechanism in which Th. ferrooxidans utilises H+ and Fe3+ as catalytic agents which break surface bonds by chemical and electrochemical mechanisms, respectively. They are subsequently recycled while the bacterium oxidises the generated surface products, — SHδ and So, etc., to sulphate. On the basis of the derived mechanism it should be possible to estimate and predict the suitability of sulphides for bacterial oxidation and to analyse the influence of crystalline quality and impurities, as well as the composition of the solution, on the rate of oxidation.
Hydrogenation of benzene to cyclohexene on an unsupported ruthenium catalyst: Effect of poisons
Authors: Odenbrand C. U. Ingemar , Lundin Sten T. 
Published: July 2010

AbstractThe influence of poisoning of ruthenium catalysing the selective hydrogenation of benzene to cyclohexene has been studied. Both the yield of cyclohexene and the rate of hydrogenation are greatly affected by the degree of poisoning (e.g. FeSO4, FeCl3, TiCl3 and oxygen), and may also be optimised. A reproducible catalyst has been prepared by precipitating the catalyst precursor, as the hydroxide, in a glass vessel at 353 K without influence of corrosion products from the reactor material. The influence of the hydrogen pressure on activity has also been investigated. An optimum pressure for maximum yield of cyclohexene was obtained and a rate expression was formulated which could account for reaction orders varying with hydrogen pressure.
The adsorption of lithium onto alumina from solutions of mixed chlorides: Effects of temperature and electrolyte control
Authors: Ding‐Xue Kang , Xiang‐Mu Shen , Xue‐Yuan Wan 
Published: July 2010

AbstractThe effects of temperature, type and concentration of electrolyte on the adsorption of lithium into amorphous hydroxide have been investigated. As a consequence of this phase change lithium was desorbed. In the presence of NaCl and, more particularly, of MgCl2 both the processes of lithium adsorption and the alumina phase change can be considerably modified.
Microcrystalline waxes. 1. Investigations on the structure of waxes by proton nuclear magnetic resonance spectroscopy
Authors: Agrawal Krishna M. , Joshi Girish C. 
Published: July 2010

AbstractInformation on the degree and type of branching in ten different microcrystalline waxes, their saturated and aromatic fractions has been obtained by proton nuclear magnetic resonance. The branches present in these waxes are of the long‐chain type with a terminal methyl group and an average of about 1.3 branches per molecule.
Liquid phase oxidation of substituted toluenes by air for the production of pharmaceutical intermediates
Authors: Borgaonkar Hemant V. , Chandalia Sampatraj B. 
Published: July 2010

AbstractLiquid phase oxidation of several substituted methyl aromatic compounds by air in an acetic acid medium, using cobalt acetate as a catalyst and sodium bromide or paraldehyde as a promoter, has been investigated with a view to developing manufacturing processes for the production of various pharmaceutical intermediates. In most cases carboxylic acids and aldehydes were the major products of oxidation. The process parameters such as temperature, period of reaction, and concentrations of the substrate, catalyst and promoter were chosen to obtain a high proportion of the desired oxidation product.
Ternary phase equilibrium studies of furfural‐water‐solvent systems
Authors: Patel Amrit N. 
Published: July 2010

AbstractPhase equilibrium and tie line data determined at 298 K for the ternary system comprising furfural, water and organic solvents (benzene, cyclohexane, pentan‐1‐ol, cyclohexanol and benzyl alcohol) are presented. The tie‐line data for the systems have been correlated by Hand's method. Among the five solvents studied, cyclohexane showed the highest selectivity followed by benzene, benzyl alcohol, pentan‐1‐ol and cyclohexan‐1‐ol, in that order.
Chemistry of the reduction of Ellman's reagent by ascorbic acid
Authors: Baker W. L. 
Published: July 2010

AbstractEllman's reagent is reduced in two stages by ascorbic acid in the presence of copper ions. The first stage involves some reversible steps and is associated with the formation of dehydroascorbic acid. In this stage, the disulphide compound probably accepts electrons in place of oxygen. The reducing power of 2,3‐diketogulonic acid, formed by delactonisation of dehydroascorbic acid, probably effects the second stage of reduction. This is only observed upon addition of EDTA at specified intervals. Two moles of sulphydryl anions are formed per mole of disulphide. The reaction is useful for following the copper catalysed oxidation of low concentrations of ascorbic acid, but is complicated by the effects of copper ion and the hydrogen peroxide formed on the coloured anion.
A study of the Pd/C catalyst for synthesis of hydroxylamine
Authors: Chang Kung R. , Chen Hwei W. , Wan Chi C. 
Published: July 2010

AbstractPalladium dispersed on active carbon (Pd/C) is used as a catalyst in the synthesis of hydroxylamine. Alkaline precipitation was used to prepare the catalyst. It was found that the controlling factor was the size of palladium crystal, which in turn was chiefly determined by the PdCl42‐/Pd(OH)2 conversion stage. The sintering and crystal growth of Pd was the main reason for the decay of the catalyst. The sintering mechanism was found to follow the Ostwald ripening model.
Studies on the adsorption of caesium, thallium, strontium and cobalt radionuclides on activated carbons from aqueous solutions
Authors: Rivera‐Utrilla José , Ferro‐Garcia Maria A. , Mata‐Arjona Andrés , González‐Goméz Cecilio 
Published: July 2010

AbstractIndividual adsorption studies of Cs+, Tl+, Sr2+ and Co2+ on activated carbons from aqueous solutions are reported. The carbon samples were characterised using different techniques. The surface area and the micro‐, meso‐ and macropore volumes of all samples have been calculated. The chemical nature of the surface of the activated carbons was also studied. Optimal conditions for the adsorption of the metal ions have been identified. The adsorption of these cations by the carbon samples was also determined in the presence of a number of different anions. The data suggest the possible use of activated carbons for the preconcentration and separation of some cations.
Time‐dependent properties of colloidal dispersions of ferric‐hydroxy polycations
Authors: Segal David L. 
Published: July 2010

AbstractThe variation of pH, unpolymerised iron(III) concentration and optical density with time after preparation for colloidal dispersions of ferric‐hydroxy polycations has been measured. Changes in these parameters are sensitive to the extent of hydrolysis of the Fe(III) ion while counter‐ions and initial ferric ion concentration affect the stability of the dispersions with respect to the formation of hydrous oxide precipitates.
The decomposition of high grade bleaching powder (calcium hypochlorite)
Authors: Bibby David M. , Milestone Neil B. 
Published: July 2010

AbstractThe decomposition of commercial calcium hypochlorite (termed here High Grade Bleaching Powder, HGBP) has been studied by X‐ray diffraction, differential thermal analysis, thermogravimetry and isothermal calorimetry, after storage at various temperatures and humidities. It was found that Ca(OCl)2 can decompose by at least three main routes. These include disproportionation to give Ca(ClO3)2 and CaCl2, and with the evolution of Cl2 or O2 depending on the presence or absence of water. The heat output of HGBP between 15 and 70°C differed considerably between samples and was found to increase after exposure to water vapour; some metal oxides also had a positive effect on the heat output. At 65°C the heat output oscillated, showing that both exothermic and endothermic reactions were taking place. At room temperature and in the absence of water HGBP appears to be stable.
Unperturbed dimensions and intrinsic viscosity‐molecular weight relationship of copolyesters poly(ethylene terephthalate‐co‐ethylene isophthalate)
Authors: Uglea Constantin V. , Mihaescu Adraiana 
Published: July 2010

AbstractThe relationship [η] = KMa and unperturbed dimensions of the copolyesters poly(ethylene terephthalate‐co‐ethylene isophthalate) with 7.5% and 25% isophthalic structures in the main chain were determined. The experimental data proved the influence of the amount of isophthalic structures upon the values of K and a from the relation between intrinsic viscosity and molecular weight and on the values for unperturbed dimensions.