bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of yttrium ions from aqueous solution by ion flotation
Authors: Rose M. W. , Sebba F. 
Published: July 2010

AbstractConditions for the concentration of yttrium from aqueous solution by ion flotation using α‐sulphonated fatty acids were studied. The effects of change of collector and colligend concentration and pH, as well as the effect of interfering ions, were investigated. Maximum recovery was 99·5%.
Some aspects of the behaviour of potassium sulphate in aqueous solutions
Authors: Halstead W. D. 
Published: July 2010

AbstractThe solubility of potassium sulphate in sulphuric acid at 293°K has been determined. The effects of traces of Fe2+, Fe3+ and Cr3+ ions on the recrystallisation of potassium sulphate from both neutral and acidic solutions have been studied. While Fe2+ ions had no significant effect, concentrations of 0.07 g Fe3+ or 0.02 g Cr2+ per 100 g H2O inhibited crystallisation of potassium sulphate from 100% supersaturated solutions. A method for purifying potassium sulphate contaminated with Fe3+ and Cr3+ ions, by means of fractional crystallisation, is outlined.
Absorption of oxygen by 2‐ethylhexaldehyde
Authors: Ladhabhoy M. E. , Sharma M. M. 
Published: July 2010

AbstractThe kinetics of absorption of oxygen by 2‐ethylhexaldehyde dissolved in 2‐ethylhexanoic acid at concentrations up to 1.38 × 10−3 mole/cm3 (20 wt.‐%), in the presence of manganese acetate, was studied in a stirred cell and in bubble and packed bubble columns. Diffusion of oxygen was found to play a major role. The reaction was first order in oxygen and second order with respect to the aldehyde, and the overall third‐order rate constant was found to be 2.98 × 107 cm6 mole−2 sec−1 at 30°. The effect of cobaltous acetate on the specific rate of absorption of oxygen was also studied and manganese acetate was found to be the better catalyst.
Mathematical models of fermentations and a simulation of the griseofulvin fermentation
Authors: Calam C. T. , Ellis S. H. , McCann M. J. 
Published: July 2010

AbstractA number of models which have recently appeared in the microbiological literature are described and discussed. A simulation of the griseofulvin fermentation is also reported.Models described range from simple models involving curve‐generating equations providing parameters which describe fermentation phenomena adequately for optimisation purposes, to more elaborate mechanistic models which involve the quantity of substrate required to produce cells and products. Beyond this are complex models capable of describing biochemical mechanisms and able to elucidate a fermentation at a deeper level.The construction of the model for griseofulvin fermentation and its comparison with actual results have shown how a model can bring to light new ideas about the way fermentations behave and point to the most useful areas of investigational work.
Composition of the gases formed in electrical insulating oils
Authors: Davies I. 
Published: July 2010

AbstractThe composition of the gases formed in electrical insulating oils can be used to detect the onset of faults in the plant. A number of methods of analysis are in use. This paper describes a method of expressing the results of an analysis which shows that most samples fall into a pattern from which deviations are assumed to indicate the presence of a fault.The procedure is described and some examples given which illustrate its use in practice.
Factors affecting the skid‐resistance of calcined bauxite
Authors: Dews S. J. , Bishop R. J. 
Published: July 2010

AbstractCalcined bauxite (RASC Grade from Guyana) has been demonstrated as an excellent, albeit expensive, aggregate material for road surfacing which has unique properties with regard to its performance under traffic. Its high wear resistance and anti‐skid properties have resulted in a dramatic decrease in the number of accidents wherever the surface has been laid. This paper discusses results from an examination of certain physical and chemical properties of this heterogeneous material and relates them to its outstanding performance as a surfacing aggregate.
Structural changes of flavylium salts
Authors: Harper Kevi N. A. 
Published: July 2010

AbstractA general discussion is presented of the effects of hydroxylation pattern upon the structural changes of flavylium salts and their stability at different pH levels. The discussion is based upon the results of spectrometric and polarographic investigations of flavylium salts and incorporates hitherto unpublished data for the anthocyanidin, cyanidin chloride.
Equilibrium distribution data for salicylic acid + water + solvent systems
Authors: Sinha Rathindranath , Rao R. Jagannadha 
Published: July 2010

AbstractEquilibrium distribution data have been presented at 30 °C for the distribution of salicylic acid between water and each of the solvents benzene, toluene, xylene and kerosene. The equilibrium distribution plots reveal that except in the case of kerosene, the acid favours the solvent layer more than the aqueous phase at higher concentrations, i.e., above 0.04 wt‐ % acid content. At lower concentrations the acid prefers more the aqueous phase. In the case of kerosene, the acid favours only the aqueous phase uniformly at all concentrations. The lower hydrocarbons seem to be better suited for the extraction of salicylic acid from the aqueous phase.
Transient behaviour of encapsulated enzyme reactor systems
Authors: Choi Paul S. K. , Fan Liang T. 
Published: July 2010

AbstractMathematical models are developed for the transient behaviour of encapsulated enzyme reactor systems such as the continuous stirred tank reactor (CSTR) and the packed bed tubular reactor. The rate processes taking place in the encapsulated enzyme bed are approximated by using a combined rate control model of enzyme reaction and membrane diffusion. The change in transient substrate concentration is obtained by using the developed rate expression in the material balance over the substrate as a function of time for the CSTR and as a function of time and position for the packed bed tubular reactor. The effects of various parameters such as the enzymic reaction rate constant, Michaelis constant, diffusional resistance of membranes, and Peclet number on the substrate concentration distribution, which varies with respect to operating time, are investigated. This study affords insight into the transient operating characteristics of the encapsulated enzyme reactor system. The results should be useful in understanding the start‐up performance of the reactor systems and to control such reactor systems at desired operating conditions.
Hydration of calcium sulphate hemihydrate in the presence of calcium hydroxide
Authors: Ridge Mayhew J. , King George A. 
Published: July 2010

AbstractA study has been made of the effects of calcium hydroxide on the hydration of calcium sulphate hemihydrate in accelerated, inhibited and unmodified systems, using techniques developed in this laboratory. The results were interpreted in terms of an equation developed earlier, and the parameters k (which is related to the transport of matter in the system) and α0 (which is a measure of heterogeneous nucleation) determined. A small addition of calcium hydroxide leads in all cases to a sharp increase in k. Further additions lead only to effects caused by dilution of the system. Calcium hydroxide has complex effects on α0. These are large in inhibited systems. The basic effects of calcium hydroxide are to increase the concentration of hydroxyl ions which have specific effects, increase the concentration of Ca2+ ions, adsorb inhibitors and extend the system as an inert diluent.
Effect of the method of preparation and pretreatment on the texture of alumina and related catalysts
Authors: Ravindram Maddury , Murty Koganti S. 
Published: July 2010

AbstractThe effect of the method of preparation and pretreatment on catalyst texture was investigated in the case of alumina, silica‐alumina, 10 × molecular sieve and thoria catalysts. All the catalysts were characterised with respect to their specific surface area, surface acidity, pore size distribution and pore volume. The above properties were found to reflect the textural changes that might have been undergone by the catalyst surface as a result of the method of preparation and pretreatment. The method of preparation was found to influence markedly the acidity of the surface and to a lesser extent the surface area and pore size distribution. Acid‐treatment was found to increase selectively the acidity of the catalyst while heat‐treatment was found to decrease proportionally the acidity as well as surface area of the catalyst.
Adsorption of dyestuffs from aqueous solutions with activated carbon I: Equilibrium and batch contact‐time studies
Authors: McKay Gordon 
Published: July 2010

AbstractThe ability of one activated carbon to remove dyestuffs from aqueous solutions has been investigated. The range of dyestuffs includes acidic, basic, disperse and direct dyes, and several factors have been studied, namely, agitation, initial dye concentration, adsorbent concentration, adsorbent particle‐size range, dye solution temperature, pH of solution and salt concentration.
Kinetics and mechanism of slag cement hydration
Authors: Abo‐El‐enein S. A. , Ata A. A. , Hassanien A. , Sh. Mikhai R. 
Published: July 2010

AbstractGranulated blastfurnace slag and Portland cement were first ground separately into samples of different fineness, covering the range 2500 to 6000 cm2 g−1 in Blaine areas. For each sample, various slag‐cement mixtures were prepared using Portland cement with the same Blaine area. Paste‐hydration of the various slag‐cement mixtures was carried out at room temperature for different curing periods; the initial W/C ratios used were 0.30 and 0.40. From the results of combined (non‐evaporable) water, free slag and free lime contents of the hardened pastes at various hydration ages, and their relation to the development in compressive strength, the mechanism of the hydration process could be specified. The suggested mechanism includes six hydration stages; these are (i) pre‐dormant, (ii) first dormant, (iii) first acceleration, (iv) second dormant, (v) second acceleration and (vi) diffusion period. The beginning and duration of each hydration period depended primarily on the fineness and the constitution of the slag‐cement dry mixture.
Lightfastness and flash photolysis of hydroxyanthraquinones
Authors: Allen Norman S. , McKellar John F. , Moghaddam Bahram M. 
Published: July 2010

AbstractThe photostability of the commercially important dye 1,2‐dihydroxyanthraquinone (alizarin) is compared with that of four other structurally related hydroxyanthraquinones in both solution and polymer substrates. In solution the flash photolysis experiments showed that in a polar solvent, 2‐propanol, the 1,2‐hydroxy derivative is the least reactive. A similar trend in lightfastness (LF) is found when the dyes are applied to the highly polar substrate nylon‐6,6.
Adsorption from aqueous solution by δ‐manganese dioxide II. Adsorption of some heavy metal cations
Authors: Gray Malcom J. , Malati Mounir A. 
Published: July 2010

AbstractThe adsorption isotherms of M2+ ions (M2+ = Ni2+, Co2+, Cd2+, Zn2+ and Mn2+) on the K+‐form of δ‐MnO2, at pH 6 and at different temperatures, fitted the Langmuir equation and an apparent heat of adsorption, Q, was found to be ‐ 78, ‐ 33, ‐ 34, ‐ 19 and ‐ 15 kJ mol−1 respectively. The adsorption capacity of δ‐MnO2 increased in the series: Ni2+ < Co2+ < Cd2+ ± Zn2+ < Mn2+. This was nearly the order of decrease in the radii, r′, of the hydrated ions, estimated from hydration enthalpies. An ionexchange mechanism between hydrated K+ ions in the outer Helmholtz layer and hydrated M2+ ions in the solution, suggests positive entropy contributions which offset the endothermic Q. The proposed mechanism is in agreement with the observed sequence of adsorption capacity and with the decrease in Q in the above series, except for Co2+ adsorption (possibly complicated by the oxidation of Co2+ by δ‐MnO2). The adsorption of the cations is probably accompanied by the exchange with Mn ions from the solid. There was evidence of specific adsorption below the point of zero charge (pH 3.3). The adsorption isotherms of Mn2+ ions at pH 7 were higher than those at pH 6 and Q was found to be ‐ 19 kJ mol−1. As the ionic strength increased, the adsorption isotherm of Mn2+ ions at pH 7 and 298 K shifted to lower values. Adsorption isotherms of Cu(II)ions at pH 3.5 and of Fe(III) at pH 2 represent specific adsorption and Q was found to be ‐ 74 and ‐ 13 kJ mol−1 respectively.
The density of an ammonia cloud in the early stages of atmospheric dispersion
Authors: Haddock S. R. , Williams R. J. 
Published: July 2010

AbstractThe variation of the density of a cloud of ammonia vapour and droplets as it mixes with dry or wet air has been examined. This has involved a consideration of the possible chemical and physical interactions of the cloud with the components of the atmosphere, the thermal effects associated with these interactions and the competing processes of evaporation and precipitation of any drops of liquid ammonia that may be present in the cloud. It has been concluded that although pure ammonia vapour even at its normal boiling point is less dense than air under ambient atmospheric conditions, there are circumstances in which a cloud of ammonia dispersing in the atmosphere may be become denser than the surrounding air.
The difficulty of reducing nitrogen oxides in the presence of oxygen
Authors: Van Den Bleek Cornelis M. , Van Den Berg Pieter J. 
Published: July 2010

AbstractA hypothesis is made, based on the literature, which makes it very unlikely that NO can be selectively reduced by any reducing agent other than ammonia. The hypothesis is based upon the very fast reduction of NO2, even in the presence of oxygen, and an easy reoxidation of NO to NO2which are both preferential to NO reduction in the presence of oxygen. The particular feature of ammonia originates from the fact that in parallel with this reaction, both reactants, under limiting conditions (defined by temperature), participate in a second scheme which leads to the formation of surface complexes dissociating into N2and/or N2O. These surface complexes are most probably NH4NO2and NH4NO3. In the presence of oxygen only this second scheme leads to the formation of N2and or N2O and is even accelerated by the re‐oxidation of NO to NO2.
Fermentation patterns of gramicidin S formation by Bacillus brevis ATCC 9999 in high‐yielding synthetic medium
Authors: Vandamme Erick J. , Leyman Dirk 
Published: July 2010

AbstractAddition of the gramicidin S (GS)‐constituent amino acids, other than the limiting precursor L‐phenylalanine, to the high‐yielding chemically defined F3/6 and G3/6 media, enhanced growth and volumetric GS‐production by Bacillus brevis ATCC 9999 considerably, but did not yield a higher specific GS‐production level. L‐Leucine alone could duplicate this stimulatory effect in G3/6 medium. Replacing the fructose component of F3/6 medium by these four amino acids yielded a high specific GS‐production level, but resulted in poor growth and low volumetric antibiotic production. Nutrient‐utilisation patterns in F3/6 medium revealed that B. brevis initially grew at the expense of L‐glutamine and L‐arginine. After a diauxic lag period, D‐fructose was consumed together with L‐histidine. L‐Proline was mainly used during the stationary phase. L‐Methionine was broken down gradually throughout the whole fermentation cycle. L‐Phenylalanine was metabolised only after GS formation started, and its disappearance was proportional to the amount of GS produced. Lowering the aeration rate caused an acidification of the medium, resulting in a slower and incomplete, although similar, nutrient‐utilisation pattern. At a controlled pH of 7.3, under lowered aeration, utilisation patterns were again comparable with those of a fully aerated fermentation, but GS levels were enhanced considerably (0.220 mg of GS mg−1 dry cell wt). Depending on environmental culture conditions, B. brevis also excreted different amino acids (L‐lysine, L‐alanine, L‐valine, L‐serine), which were in turn metabolised during late growth and differentiation stages. The onset of GS synthesis occurred on depletion of L‐glutamine and L‐arginine. Soluble GS synthetase 1 and 2 peaks coincided with ‘diauxic’ lag phases; this supported the idea that a high growth rate is incompatible with GS synthetase formation.
Antibiotics from the newly isolated Streptomyces elizabethii. I. Production of a polyene antifungal agent (Elizabethin) and actinomycin in shake flask cultures
Authors: Pirt S. John , Pickett Susan M. A. , Pickett Andrew M. , Vandamme Erick J. , Bird Clive W. 
Published: July 2010

AbstractA new streptomyces strain, designated Streptomyces elizabethii, was isolated from a soil sample using a method which selected antifungal antibiotic producers. S. elizabethii produces an antifungal polyene (elizabethin) and antibacterial actinomycins. Optimal conditions were elucidated for sporulation of the streptomycete in bottle cultures and for polyene production in shake flask cultures. High sugar concentrations were found to repress actinomycin biosynthesis and increase polyene production. Excess potassium phosphate inhibited polyene production.
Separation of close boiling substituted phenols by dissociation extraction
Authors: Wadekar Vishwas V. , Sharma Man Mohan 
Published: July 2010

AbstractSome mixtures of substituted phenols, which are difficult to separate by established methods such as distillation, crystallisation, etc., have been separated by dissociation extraction. Di‐n‐butyl ether was found to be an excellent solvent for the systems: phenol‐o‐chlorophenol; p‐chlorophenol‐2,4‐dichlorophenol; o‐cresol‐6‐chloro‐o‐cresol. In the case of m‐cresol‐2,6‐xylenol and p‐cresol‐2,6‐xylenol, benzene was found to be a good solvent. For the system: 4‐chloro‐m‐xylenol‐2,4‐dichloro‐m‐xylenol dissociation extraction in a solid‐liquid system without a solvent gave higher values of separation factor than a liquid‐liquid system. In all the cases, agreement between the experimental and theoretical values of separation factors was found to be reasonable.
Bioleaching of copper from a low‐grade chalcopyrite ore
Authors: Deepak Desh , Das Kumudeswar 
Published: July 2010

AbstractExperiments conducted in this study provide good evidence that the rate of oxidation of chalcopyrite can be increased many fold by the action of the iron‐oxidising, chemoautotrophic bacteria, Thiobacillus ferrooxidans. Studies were made between the range 28–48°C and between pH 2.0 and 3.5. The optimum temperature and pH were found to be 35°C and 2.7, respectively. Particle sizes of chalcopyrite ore used in the study were between 60 and 190 μm in diameter. The rate of leaching was found to be directly proportional to the decrease in particle size. Supply of air to the system had a pronounced effect on the leaching of chalcopyrite by T. ferrooxidans. During the same period of 48 days, the conversion of copper obtained was 17.8, 58 and 54.4% in stationary, a shake flask and a percolator system, respectively.
Disproportionation of toluene over a metal‐supported type L‐zeolite catalyst
Authors: Halgeri A. B. 
Published: July 2010

AbstractThe disproportionation of toluene was studied using KHL zeolite, with and without metal supports. Incorporation of Ni and Pt to KHL increases significantly the surface acidity and catalytic activity. Their change in surface acidity due to metal‐zeolite interactions predominantly influences disproportionation activity. The performance of metal‐loaded zeolites is also better than that of KHL in terms of initial activity and stability. The effects of the metal, temperature and the carrier gas have been investigated. The bifunctional nature of metal zeolites as represented by the hydrogenation activity of the metallic component and disproportionation activity of acidic zeolites has been established.
The dielectric behaviour of lithium acetylacetonate
Authors: Molokhia N. M. , El‐Shahat M. F. 
Published: July 2010

AbstractThe dielectric constant and loss tangent of lithium acetylacetonate [Li(ac.ac)] have been measured at different frequencies for different temperatures. The results show that the dielectric behaviour of Li(ac.ac) is different from that of Na(ac.ac) and K(ac.ac) which exhibit a ferroelectric‐like behaviour. The activation energy of Li (ac.ac) was found to be 0.54 eV, nearly half the value for K(ac.ac). The infrared absorption spectra of Li(ac.ac) shows that in this compound the lithium metal resembles group II rather than group I.
Physico‐mechanical characteristics of hydrating tetracalcium aluminoferrite system at low water: Solid ratios
Authors: Ramachandran Vangipuram S. , Beaudoin James J. 
Published: July 2010

AbstractTetracalcium aluminoferrite (C4AF) mixed with gypsum in amounts of 0, 5, 10, 20 and 30% was hydrated at 25 or 80°C, either as discs (formed at pressures of 140 and 690 MPa to obtain an effective water:solid ratio of 0.08 and 0.13, respectively) or in powder form at water:cement ratios of 0.5 and 1.0. Hydration products formed at periods ranging from a few minutes to 7 days were identified and estimated. The sequence of hydrate formation and the accompanying length changes were also determined. The formation of hexagonal hydrate, cubic hydrate, ettringite, low sulphoaluminate series and their interconversions was primarily dependent on gypsum content, temperature, and initial water:solid (w/s) ratio. The study indicates that ettringite need not necessarily be a precursor of the formation of low sulphoaluminate hydrate when hydration is carried out at a very low w/s ratio at 80°C. The microhardness and porosity characteristics of the hydrated products were compared after 2 days of hydration. The relative contribution of low sulphoaluminate, ettringite, and other hydrated phases on strength development were assessed.
Oxidation products of secondary butyltoluene — a 1H‐n.m.r. study
Authors: Kulsrestha Girendra N. , Joshi Girish C. 
Published: July 2010

Abstractα‐Primary‐ and α‐tertiary‐hydroperoxides and alcohols, methylacetophenone, s‐butylbenzaldehyde, s‐butylbenzyl ether, and 2‐tolylbut‐2‐ene were identified in s‐butyltoluene oxidates. The quantitative estimates of hydroperoxides and acetophenone by 1H‐n.m.r. compared within ca 2% with those obtained by chemical methods and gas‐liquid chromatography respectively. Unlike chemical methods, the procedure is quick, non‐destructive and unaffected by structural complications.
Study of the heterogeneous reaction between iron and lead oxides
Authors: Vetere Vicente F. , Romagnoli Roberto 
Published: July 2010

AbstractDifferent theories are proposed in the literature to explain passivation mechanisms of iron by means of the use of lead compounds. In some cases the protective action is related to the formation of lead soaps with vegetable oils or oleoresinous binders. These soaps are partially dissolved from the film, acting at the interface metallic substrate/paint film. In the case of inert binders (those corresponding to vinyl resins), red lead acts as a passivating agent. The protection of iron plates in the presence of suspensions of red lead, lead monoxide and lead dioxide in a 0.5M sodium perchlorate solution as electrolyte is studied in this paper. Polarisation curves were traced and measurements of voltage at open circuits were made. Only two of the lead oxides tested (red lead and lead monoxide) have corrosion inhibiting action, both showing a similar behaviour.