bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the pulping of egyptian cotton linters by the nitric acid process
Authors: Abou‐State M. Amine , El‐Megeid Fouad F. Abd 
Published: July 2010

AbstractEgyptian cotton linters were pulped by the nitric acid process. In order to reduce the high ash and silica contents of the resulting pulps it was found necessary to apply hot refining with sodium hydroxide solution. Different conditions of concentration, temperature, and pressure in the refining step were investigated. Refining before and during bleaching were compared.
Study of solvents for butadiene extraction by gas chromatography
Authors: Rawat B. S. , Mallik K. L. , Gulati I. B. 
Published: July 2010

AbstractSix solvents have been studied by GLC for separation of 1,3‐butadiene from C4‐olefins having close boiling points. Infinite dilution activity coefficients and partition coefficients of five olefins have been determined in these solvents by conventional GLC‐technique at 30 °C. Relative volatilities of olefins in solvents have been calculated and on this basis the solvents have been compared.
The use of PVC powder as a subtractive agent in gas chromatography
Authors: Jamieson I. L. 
Published: July 2010

AbstractAn investigation is described in which subtraction “loops” filled with PVC powder have been used to study the affinity between the powder and model compounds. Optimum temperature conditions are 70 °C. The study reveals that the PVC has a strong affinity for aromatic compounds and compounds containing functional groups although this is qualified by the configuration of the molecule. It is shown that in view of these properties PVC can be used in subtraction “loops” as an aid to the identification of aromatics in mixtures of aromatics, n‐, iso‐ and cycloparaffins and also that its effectiveness in differentiating between aromatics and n‐paraffins is comparable with molecular sieve 5A. Its behaviour is different, however, in that it removes aromatics whereas the molecular sieve 5A removes the n‐paraffins. It is as effective as molecular sieve 5A in removing hydrocarbons containing functional groups. The PVC is cheap, requires no preparation prior to use and when “exhausted” it can be readily replaced.
Ternary vapour‐liquid equilibria of the system acetone+chloroform+tetrachloroethylene
Authors: Dakshinamurty P. , Rao P. Venkateswara , Chiranjivi C. 
Published: July 2010

AbstractIsobaric vapour‐liquid equilibrium data of the ternary system acetone + chloroform + tetrachloroethylene were determined at 760 mmHg total pressure using a modified Colburn still. The activity coefficient data were satisfactorily tested for their thermodynamic consistency by the method of McDermott and Ellis and a satisfactory correlation was also obtained through Wohl's three suffix Margules ternary equations without a ternary constant. No ternary azeotrope was observed.
Effect of dialdehydes on the viscosity and optical rotation of gelatin
Authors: Courts A. , Homan P. 
Published: July 2010

AbstractMonoaldehydes, other than formaldehyde, do not increase the viscosity of gelatin. Dialdehydes can increase viscosities, the order of efficiency being.Glutaraldehyde increases the specific rotation of gelatin sols and gels but this effect usually requires a maturing time before it becomes apparent. After 18 h the increase is about 8%. Hence molecular order can adjust within gel structure. Cross‐linking gelatin does not improve the mechanical hardness of the film produced, as shown by indentation measurements.The specific rotation of gelatin film is about one‐third the value of gelatin in the sol state.
Significance of the solubility of hydrocarbon gases in liquids in relation to the intermolecular structure of liquids and the essential pattern of data for all gases
Authors: Gerrard William 
Published: July 2010

AbstractSolubility data expressed as mole ratio, xRH (moles of RH per mole of liquid S) have been measured for propane and n‐butane in a number of type‐representative organic liquids, S, at different temperatures, t °C, and pressures, pRH ≤ 760 mm. These data, and those for methane, ethane and radon, afford support in the development of the essential pattern of data for all gases, A, and all liquids, S. This pattern indicates that the first factor determining the solubility of any gas, A, in any liquid, S, is its tendency to condense to a liquid at the operational temperature, t °C (e.g. 0 °C to 25 °C), shown by its vapour pressure p°A over liquid A (or its equivalent for a gas above the critical temperature) at t °C. Since p°A emerges from the b.p. of A at 1 atm, and b.p. data are readily seen in text‐books, the b.p. may be taken as an initial index of the first factor. In the NA–pA diagram for a given gas A and different liquids, S, at a fixed t °C, NA being the mole fraction of A, the straight line joining p°A with pA = 0 is herein called the reference line, the R‐line, of A; it is a real property of A, and it represents the plot of NA–pA for a hypothetical liquid, S, having in effect an overall inter‐molecular structure equivalent to liquid A, in imagination, A itself. The NA–pA plot for another liquid, S, involves a second and a third factor, the second being the intermolecular structure of S, in a dynamic sense, and the third, the inevitable interaction of A with S. These factors are deemed to emerge from changes in electron density, designated for the present as acid‐base functions. The spread of xRH values is indicated by xPrH = 0.322, xBuH = 5.25, for di‐n‐octyl ether; xPrH = about 0.000042, xBuH = about 0.000040, for water, for 5 °C and PRH = 760 mmHg.
A multilayer thickness relationship applicable to pore size analysis of silica gel
Authors: Girgis Badie S. 
Published: July 2010

AbstractA single multilayer curve was arrived at for the adsorption of nitrogen on silica gel. An empirical equation, fitted to the curve, proved to be suitable in the pore size analysis of 26 samples of silica gels; specific surface areas from 178 to 814 m2/g, mean pore radii of 12.6 up to 74.4 Å, and total pore volumes of 0.5126 to 0.8613 ml/g. Cumulative surface areas were evaluated by the procedures of BJH, Cranston and Inkley, and Roberts; the values obtained were generally in agreement with specific surface areas obtained by the BET equation, SBET, within ± 5%. The empirical equation is completely independent of the structural characteristics of the material. Comparison was made with data obtained by the use of the method of Mingle and Smith, for evaluating multilayer thickness, and which depends on both mean pore radius, and BET‐C value, for each single solid. Good concordance appears between the cumulative surface areas, as well as the pore size distributions, calculated by employing either this latter t‐estimate or the empirical equation.
Separation of uin‐ and multivalent cations and selective de‐ionisation by a phosphonic cation exchanger
Authors: Kadlec Václav , Matějka Zdeněk 
Published: July 2010

AbstractThe phosphonic cation exchanger in its free acid form is able to remove multivalent cations even from neutral and medium acidic solutions of salts of strong acids completely, and is regenerated by a stoichiometric amount of a regenerating agent. It is therefore possible to separate multivalent cations from univalent cations in a simple way by means of a phosphonic cation exchanger, followed by a weakly basic anion exchange resin. This results in a selective or partial de‐ionisation of solutions with an eventual recovery of multivalent cations using an economical regeneration dosage and with a minimum of waste.
An empirical thermodynamic model for the ammonia—water—carbon dioxide system at urea synthesis conditions
Authors: Lemkowitz Saul M. , De Cooker Mario G. R. T. , Van Den Berg Pieter J. 
Published: July 2010

AbstractAn empirical thermodynamic model for the NH3–H2OCO2 system at equilibrium at urea synthesis conditions (140 ≤ T ≤ 200 °C, 50 ≤ P ≤ 250 atm, 2.4 ≤ NH3/CO2 ≤ 6, H2O/CO2 ≤ 0.5) is presented. This model can quantitatively or semi‐quantitatively describe a number of important phenomena in the urea synthesis, such as the bubble‐point and gas—liquid equilibrium conditions and the effect of excess ammonia and water on the conversion to urea in the liquid phase. The model also sheds light on the problem of the conversion to urea at high temperatures (T > 190–200 °C).
Carnallite decomposition into magnesia, hydrochloric acid and potassium chloride: A thermal analysis study; formation of pure periclase
Authors: Ashboren David 
Published: July 2010

AbstractA thermal analysis study of the one‐stage decomposition of small (mg) quantities of carnallite, KCl. MgCl2, 6H2O → KCl + MgO + 5H2O ↑ + 2HCl ↓, showed that dehydration and hydrolysis require temperatures above 300 °C. Decomposition of greater amounts, and analysis of the products, showed that at 450 °C, 88 to 90% of the magnesium occurs as chloride‐free high‐purity periclase. At higher temperatures increasing amounts of chlorides remain in the periclase and are difficult to separate. Unglazed porcelain is a suitable material for the decomposition vessel.
A study of the reaction of dry hydrogen chloride with white lead suspended in di—2—ethyl hexyl phthalate at 182 °C
Authors: John Michell E. W. 
Published: July 2010

AbstractIn order to test certain ideas which have recently been formulated on the way in which basic lead compounds stabilise polyvinyl chloride against thermal decomposition, the reaction of dry hydrogen chloride with a suspension of white lead in hot di‐2‐ethyl hexyl phthalate was studied by withdrawing samples and examining the solids by X‐ray diffraction. Normal lead phthalate, and an uncharacterised substance which has been called “basic lead chloride X”, were formed initially. Subsequently, this basic lead chloride X was converted to normal lead chloride.The continuous formation of normal lead phthalate in this experiment contrasts with observations made on the crystalline products of stabilising reactions in PVC blends containing basic lead carbonates, and suggests that there are fundamental differences between the reaction mechanisms which prevail in these two systems. It is proposed that the results obtained with PVC blends are best explained in terms of free‐radical mechanisms for thermal decomposition and stabilisation of this polymer, whereas the results obtained in the present experiment can be explained by a simple acid—base type reaction.X‐ray powder diffraction data are tabulated for normal lead phthalate.
Dimethyl sulphoxide as a solvent for amylose in the determination of amylolytic activity
Authors: Griffin Patrick J. , Fogarty William M. 
Published: July 2010

AbstractAmylose readily dissolves in dimethyl sulphoxide (DMSO) to give clear colourless solution which is stable and forms a convenient stock amylose solution for amylase determinations. Dimethyl sulphoxide has no inhibitory effect on different amylolytic enzymes at the concentrations required for enzyme assay.
Production of cyclodextrin glycosyltransferase by batch and chemostat culture of Bacillus macerans in chemically defined medium
Authors: Lane A. G. , Pirt S. J. 
Published: July 2010

AbstractA chemically defined medium for cultivation of Bacillus macerans is reported. Growth rates and cyclodextrin glycosyltransferase (CGT) titres obtained were similar to those obtained using media containing potato extract. The proteins in supernatant fluids from a batch culture were separated by disc electrophoresis and results obtained showed that CGT was produced after growth ceased, in agreement with results of activity measurements. The maximum growth rate in the chemostat considerably exceeded that in batch culture; this anomalous effect is unexplained. High CGT titres were produced at low dilution rates (0.03 to 0.05 h−1) but residual starch was present at higher dilution rates and CGT synthesis was repressed. Enzyme titres obtained in chemostat cultures at D = 0.03 h−1 using defined medium containing 13 g starch/1 were 2.75 times greater than the maximum obtainable by batch cultivation and about 20 times greater than those reported by other workers using medium containing diced potato and CaCO3. A two‐stage chemostat cultivation was performed using dilution rates of 0.1 h−1 and 0.033 h−1 in the first and second stages, respectively. The CGT activity in the second stage increased by 57 per cent when a maintenance feed of starch was supplied at 0.08 g g−1 dry biomass h−1. Only negligible CGT titres were obtained when a dilution rate of 0.5 h−1 was used in the first stage. For reasons not understood, DM medium would not support biomass yields greater than 5 g 1−1. This limitation was not due to production of an inhibitor, or to deficiency of N, Fe, Zn, Mn, thiamine or biotin.
Loss of copper from oxychlorination catalysts
Authors: Aharoni Chaim , Inbar Jonathan 
Published: July 2010

AbstractDuring the oxychlorination process, there are losses of copper from the catalyst as a result of a reaction with the walls of the reactor: the cupric ions are reduced to metallic copper and deposited on the walls. We have observed rates of deposition of the order of 10−2 g of copper per cm2 of walls per year, for walls of pure iron. The deposited copper was detected and estimated by electron‐probe microscopy. Attrition does not appreciably change the concentration of copper in the catalyst particles.
A quantitative theory of the action of microbes attached to a packed column: Relevant to trickling filter effluent purification and to microbial action in soil
Authors: Pirt S John 
Published: July 2010

AbstractA packed column with microorganisms attached is regarded as a series of “theoretical compartments” each separated by a “theoretical film” of biomass. Liquid medium is supposed to pass down the column so that it remains for an equal time in each compartment. The theoretical film of biomass is assumed to have an active layer in contact with the liquid medium, the thickness of the active layer of biomass is estimated from the kinetics of diffusion of the limiting substrate. The efficiency of the column is represented by the number of theoretical compartments per unit length of column. In aerobic processes it is supposed that oxygen will be the rate‐limiting nutrient. Expressions are derived for the amounts of substrate that will be consumed in aerated and non‐aerated columns. The theory is applied to calculate some of the parameters of a trickling filter for effluent purification. The theory may be readily tested since it involves only measurable and meaningful parameters of a microbial culture.
The effect of temperature, light and some transitional metal ions on the sorption of sulphur dioxide by paper
Authors: Atherton James B. , Hudson F. Lyth , Hockey John A. 
Published: July 2010

AbstractThe sorption of sulphur dioxide by a series of laboratory‐made paper handsheets of typical furnishes was investigated. The gas phase SO2 concentrations used approached those found in city atmospheres. It was found that at fixed gas phase SO2 concentration, increase in temperature decreased the “pick‐up” rate. Copper and manganese ions were found to catalyse the fixation of sulphur dioxide but iron ions were found to be much less effective in this respect. Experiments conducted to assess the effect of light indicated that the rate of “pick‐up” was increased when the samples were exposed to sunlight; an effect most marked in the samples containing groundwood.
The use of a membrane electrode to study the crystallisation of calcium sulphate from aqueous solution: I. The relation between calcium ion activity and crystallisation rate
Authors: Ching William , McCartney Eric R. 
Published: July 2010

AbstractA semipermeable membrane of sulphonated polyvinylidene fluoride was used as the basis of a membrane electrode for the measurement of the activity of calcium ions in solution. By following the change in calcium ion activity as calcium sulphate dihydrate crystallised from aqueous solution, an equation for the rate of crystallisation was derived.
Anodic behaviour and passivation of tin in alkaline—stannate plating solutions
Authors: Azzam A. M. , Abd Rehim S. S. El , Fawzy M. H. 
Published: July 2010

AbstractThe electrochemical behaviour of tin was studied in sodium hydroxide solutions as well as in alkaline—stannate plating solutions using potential—time and current—time measurements. Cyclic cathodic and anodic polarisation, as well as anodic decay curves were traced. Results indicate that the galvanostatic potential—time curves consisted of three main parts: an initial linear instantaneous rise of potential caused by the charging of the double layer, an intermediate rise caused by stannous and stannic hydroxides and oxides formation at their respective thermodynamic potentials, and a final steady potential associated with oxygen evolution.Current‐time measurements show that tin could be passivated in all solutions used and at different current densities. In all cases oxygen evolution was noticed at the end of passivation. Free surface area of tin electrode in various solutions used was calculated using the Müller formula. The porosity of the surface film was found to depend on the composition of the solution.
Thermal high pressure hydrogenolysis II. The thermal high pressure hydrocracking of fluorene
Authors: Oltay Ernst , Penninger Johannes M. L. , Konter Willem A. N. 
Published: July 2010

AbstractThe thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2‐methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low concentrations of diphenylmethane were detected at the highest temperature. This indicates that the opening of the phenylCH2 bond in fluorene is much faster than the splitting of the phenyl—phenyl bond. The splitting of the phenyl—phenyl bond in biphenyl, however, proceeded with a rate equal to the splitting of the phenylCH2 bond in fluorene and the phenylCH3 bond in 2‐methylbiphenyl.
Ageing of some high surface area solids
Authors: Bye Gerald C. , Chigbo Gilbert O. 
Published: July 2010

AbstractThe ageing (fall in surface area) of samples of aluminium hydroxide has been studied by observing the changes in surface area and porous texture revealed by nitrogen adsorption. Ageing was carried out over phosphorus pentoxide and at 33% r.h. The effect of this change in r.h. depended on the texture of the aluminium hydroxide. Ageing was faster at 33% r.h. in the amorphous form which contained discrete flocs. Pseudoboehmite behaved as a true xerogel and some samples even increased in surface area by swelling when stored at the higher humidity.Some data for calcium silicate hydrates and samples of a commercial pyrogenic silica are included for comparison. The former were prepared in powder and paste (xerogel) form. The two forms responded differently to the two humidities but in the opposite sense to the corresponding aluminium hydroxide textures: thus the surface area of pastes fell more rapidly at the higher r.h. The surface area of samples of the silica fell when they were stored normally in air tight containers. They eventually reached steady values and a reduction of a similar magnitude could be produced rapidly by agglomerating the spherical particles in hot water.Mechanisms of ageing involving simple adhesion and its reverse depending on r.h., hydroxyl group condensation, and sintering aided by dissolution or surface diffusion are discussed.
Salts in gypsum and calcined gypsum
Authors: King George A. , Ridge Mayhew J. , Walker Graham S. 
Published: July 2010

AbstractChloride in a number of samples of gypsum and calcined gypsum has been determined by Surkevicius's method and by nephelometry. Results from the former method are confirmed. Sodium was determined by atomic absorption spectroscopy and the content found to be considerably greater than the equivalent of the chloride. Two of the samples appeared to contain close to 0.1% of Na2SO4 and it is suggested that standards for the quality of gypsum should specify the determination of sodium as well as that of chloride.
Hydration of tricalcium silicate at elevated temperatures
Authors: Odler Ivan , Skalny Jan 
Published: July 2010

AbstractThe early hydration of tricalcium silicate, Ca3SiO5, has been studied at temperatures of 25, 50, 75 and 100 °C. Changes in the chemical composition of hydration products formed at different temperatures were followed by means of chemical, thermal and X‐ray analyses, and correlated with surface area and pore structure measurements reported previously.
Oxidation of ferrous sulphate in presence of sodium carbonate
Authors: Prasad T. P. , Suryanarayana A. 
Published: July 2010

AbstractIsothermal oxidation of ferrous sulphate heptahydrate in presence and absence of sodium carbonate has been carried out in the temperature range 205 to 265 °C. The oxidation proceeds in two steps. The rate constants for the oxidation at various temperatures have been calculated. The results indicate that the low temperature mechanism of oxidation proposed earlier does not hold good at higher temperatures.
Determination of oxygen‐to‐metal ratios in metal oxide nuclear fuels
Authors: Gurumurthy Coimbatore V. 
Published: July 2010

AbstractMethods for the determination of O/M ratios in uranium and uranium‐plutonium oxide nuclear fuels are reported based on an extensive literature survey. The salient features, as well as the merits and drawbacks of each method are critically reviewed. The need for a fast direct method, by which the simpler indirect methods may be checked, is met by the carbon‐reduction method.
Kinetics of the decomposition of perpropionic acid
Authors: Gurumurthy Coimbatore V. 
Published: July 2010

AbstractThe decomposition of perpropionic acid, in the presence of manganese propionate catalyst is studied by the capacity‐flow method. The reaction is found to be second order with respect to peracid concentration and first order with respect to catalyst concentration. The activation energy is 10.2 kcal/mol. The mechanism of the reaction is discussed along with the possible modes of by‐product formation.
Formation of a glass‐ionomer cement based on an lon‐leachable glass and polyacrylic acid
Authors: Crisp Stephen , Wilson Alan D. 
Published: July 2010

AbstractThe chemistry of the cement‐forming reaction between a fluorine‐containing calcium aluminosilicate glass and aqueous solutions of poly(acrylic acid) has been studied using infrared spectroscopy and classical chemical procedures. It was concluded that calcium, aluminium and fluoride ions were leached from the glass leaving a relict of silica gel. These ions migrated into the polyelectrolyte phase where the cations cross‐linked polyanionic chains causing the system to gel. Initial set, which takes place within 10 minutes, was attributed to the formation of the calcium salt, the aluminium salt forming later and contributing to the hardening of the cement. Reactions continued for at least 48 h. The role of ion‐binding in the reaction is discussed.
Extraction of titanium dioxide (TiO2) from ilmenite and titaniferous slag
Authors: Easteal Allan J. , Udy David J. 
Published: July 2010

AbstractSolutions of ilmenite (FeTiO3) and a titaniferous slag, in fused Li2O. 2B2O3 and Li2O. 4B2O3, yield on cooling compounds tentatively identified as LiFe2.5Ti3O9 and Li2Fe3Ti2.5O9 respectively. Both compounds are orthorhombic, and have the pseudobrookite structure.The ilmenite solutions yield, in addition, rutile (TiO2). The yield of rutile increases from about 1 to 24% (w/w) of the products, when the solvent is changed from Li2O. 2B2O3 to Li2O. 4B2O3. Substitution of K2O. 4B2O3 for the latter solvent decreases the yield of rutile to c. 10%. The yield of rutile is approximately in inverse proportion to the Lux—Flood basicity of the borate solvent.