bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulp and paper from corn stalks
Authors: Amine Abou‐State M. , Zimaity Tawfik , El‐Masry Ahmed M. 
Published: July 2010

AbstractThe whole corn plant was successfully used for the production of pulp and paper by employing comparatively simple procedures of atmospheric pressure digestion followed by multi‐stage bleaching. Water pre‐treatment was found necessary to remove the dust particles. However, the use of boiling water was not recommended. The effects of the amount of active chlorine in the hypochlorite step on the optical and the physical‐strength properties of paper were investigated. One‐and two‐stage pulping were compared and the effect of depithing after the first stage was studied.
Investigation of the energetics of methane‐utilising bacteria in methane‐ and oxygen‐limited chemostat cultures
Authors: Nagai Shiro , Mori T. , Aiba S. 
Published: July 2010

AbstractA special apparatus was used to establish methane‐ and oxygen‐limited chemostat cultures of a methane‐utilising bacterium, at 30 °C, pH = 7.0, respectively. Although total growth yields with respect to methane and oxygen were hardly affected by dissolved oxygen concentration in the medium, provided dilution rate was kept nearly at 0.1 h−1, these values appeared to increase slightly with the increase of dilution rate. Assuming that no metabolites other than carbon dioxide and water were produced during bacterial growth, maintenance coefficients and true growth yields were assessed from specific rates of methane uptake and respiration. These energetic constants, nearly independent of the limiting substrates, either methane or oxygen, were compared with those from published data on facultative and obligate aerobes, including a mixed culture of methane‐utilising bacteria.
The vapour—liquid equilibria of the binary, ternary and quaternary systems formed by acetone, methanol, propan‐2‐ol, and water
Authors: Verhoeye Lucien , De Schepper Herman 
Published: July 2010

AbstractThe vapour‐liquid equilibrium data of the binary, ternary and quaternary systems that may be formed by combination of the components acetone, methanol, propan‐2‐ol and water, have been determined at 760 mmHg by means of an equilibrium still based on the principle of circulation of both phases. The binary data have been correlated by means of the Margules and of the Wilson equation. The data of the ternary and quaternary systems have been predicted by these equations. The results of both equations are discussed and compared.
The choice of sampling tube material in the determination of nitrogen oxide concentrations in products of combustion
Authors: White Alan , Beddows Linda M. 
Published: July 2010

AbstractIt has been confirmed that when hot products of combustion containing traces of nitrogen oxides are sampled through metal tubes the concentration falls. The mechanism is in part due to the conversion of nitrogen dioxide to nitric oxide. Glass tubing may be used as a substitute at high sampling temperatures and PTFE is suitable at lower temperatures; nylon, EVA and PVC tubing should not be used since significant losses may occur in these materials even at room temperature.
Changes in south‐east anatolian bitumens and their main fractions under various oxidative conditions
Authors: Tüzün C. , Yaǧiz F. 
Published: July 2010

AbstractFractional analyses of South‐East Anatolian bitumens were made using Marcusson's method and changes in fractional compositions and in functional groups under oxidative conditions were investigated. A more detailed study was carried out on the asphaltic resins fraction of bitumen of Maǧrip origin, since, of those tested, this bitumen proved to be the most susceptible to oxidative conditions.
A simple high‐temperature infrared cell and its application to the dehydroxylation of kaolinite
Authors: Mackenzie Kenneth J. D. 
Published: July 2010

AbstractA simple method is described for making infrared measurements on solids at temperatures up to the melting point of KBr by using a fine nichrome heating coil wound directly on to the KBr disc containing the sample either in suspension or sedimented on to the surface. The usefulness of the method is illustrated by intensity measurements of the hydroxyl stretching bands in kaolinite as a function of temperature, which are compared with results obtained by the more conventional quenching method.
Oxidation of ferrous hydroxide suspensions. I
Authors: Prasad T. P. , Ramasastry V. V. 
Published: July 2010

AbstractFerrous hydroxide suspensions, obtained by the addition of calcium hydroxide to ferrous sulphate solution have been oxidised at room temperature (28 ± 3 °C). The extent of oxidation and the rate of oxidation were studied as a function of time by varying the air flow rate, concentration of calcium hydroxide (stoichiometry) and the concentration of ferrous sulphate. Expressions have been obtained giving the relation between velocity constant, k, and the air‐flow rate as well as between k and concentration of ferrous sulphate.
Anion exchange of uranium from aqueous sulphuric acid solutions: Diffusion kinetics
Authors: Barnes C. D. , Da Silva Neves R. A. , Streat M. 
Published: July 2010

AbstractThe ion exchange kinetics of uranium sorption from acidic sulphate solutions onto weak and strong base resins has been studied. In order to facilitate experimentation and analysis, isotopic redistribution experiments of uranyl sulphate ions (with U‐235 as a tracer) under conditions of particle diffusion control have been performed. Also, self‐diffusion experiments for sulphate ions (with S‐35 as a tracer) and counter diffusion measurements involving uranyl sulphate‐sulphate exchange have been performed. The ion exchange of uranium is a slow reaction and appears to be particle diffusion controlled at all solution conditions of practical interest. For a weak base resin (Relite MG‐1), the self‐diffusion coefficient of uranyl sulphate ions changes with particle size, increasing from 1.49 to 4.88 × 10−9 cm2/s as the particle diameter is reduced from 0.146 to 0.054 cm. With a strong base resin (Dowex‐1×8), the self‐diffusion coefficient of uranyl sulphate ions remains reasonably constant with varying particle diameter at a value of 1.76 × 10−9 cm2/s. Sulphate ion self‐diffusion coefficients were also constant with particle size (2.50 × 10−7 cm2/s) and the counter exchange diffusivity lies between the values for the individual species; a typical value is 1.53 × 10−8 cm2/s. It is argued that resin matrix structure has a significant effect on uranium kinetics and that a knowledge of the relevant diffusion coefficients will provide a rational basis for the design of ion exchange processes and plant equipment.
1,2‐Asymmetric induction when grignard reagents are added to α‐aminoketones. II. Structural effects. Application to the stereoselective synthesis of α‐aminoalcohols
Authors: Gaset Antoine , Audoye Paul , Lattes Armand 
Published: July 2010

AbstractThe best conditions for obtaining selectively diastereoisomeric aminoalcohols have been determined in an example where the combination of environmental and structural effects has controlled the addition of Grignard reagents to α‐aminoketones.
Extraction of some mineral acids by high molecular weight quaternary ammonium chloride
Authors: Sato Taichi , Watanabe Hiroshi , Kikuchi Shoji 
Published: July 2010

AbstractThe distribution equilibria of hydrochloric, nitric, perchloric, sulphuric and phosphoric acids between aqueous solutions and a solution of tricaprylmethyl‐ammonium chloride in organic solvent have been investigated. The organic phases have been studied by infra‐red and nuclear magnetic resonance spectroscopy. As a result, it is found that at low aqueous acidity the extraction of these acids is governed by the ion exchange reaction, forming the mono‐quaternary ammonium salts of monobasic acids and the mono‐, di‐ (and tri‐) quaternary ammonium salts of di‐ (and tri‐) basic acids, and at higher acidity by the formation of the adducts to quaternary ammonium salts with additional acids.
Variations in gypsum and the reactivity of its product of calcination
Authors: Ridge Mayhew J. , King George A. , Molony Bruce C. 
Published: July 2010

AbstractFive samples of Australian gypsum and one from Thailand were analysed chemically and subjected to comparable degrees of grinding and calcination. During hydration of the products considerable differences were found in the periods of induction and other kinetic parameters. Both differences in nucleation, and in the transport of calcium sulphate from the grains of hemihydrate to the growing crystals of dihydrate, seemed to contribute to the variations in reactivity. The variations did not seem to be related to the content of sodium sulphate, but a connection with that of chloride was indicated. The samples of gypsum varied in their susceptibility to transformation to orthorhombic calcium sulphate.
A new method for the preparation of acicular goethite crystals
Authors: Derie R. , Ghodsi M. , Hourez R. J. 
Published: July 2010

AbstractA new method of preparation of goethite (α‐FeO(OH)) is described. It involves simultaneous oxidation and precipitation from a solution of FeSO4 by means of the addition of a mixture of sodium hypochlorite and sodium carbonate. It is possible to use other oxidants and other alkaline substances. One can also coprecipitate various heteroelements. A brief description is given of the effect of these foreign elements on the magnetic properties of the oxides of the type γ‐Fe2O3 obtained after subsequent reduction and reoxidation.
A dry electrochemical cell containing cupric chloride supported by γ‐alumina
Authors: Aharoni Chaim , Inbar Jonathan , Roker Moshe , Rosenzweig Nahum 
Published: July 2010

AbstractAn electrochemical cell was formed by enclosing a commercial catalyst containing cupric chloride supported by γ‐alumina between electrodes of copper and iron. The voltage obtained is a logarithmic function of the vapour pressure of the water sorbed by the support. Voltages of a few hundred millivolts are obtained at relative pressures between 0.1 and 0.8 and temperatures between 25 and 170°C.
Ultraviolet absorption spectra: Some substituted benzoic acids
Authors: Kamath B. V. , Mehta J. D. , Bafna S. L. 
Published: July 2010

AbstractThe u.v. absorption spectra of 22 monosubstituted and 19 disubstituted benzoic acids have been studied in water or aqueous dioxan over a pH range of about 1–8. The isosbestic points have been measured and the results are discussed.
Densities of urea–ammonia–water–carbon dioxide solutions in chemical equilibrium at and above urea synthesis conditions
Authors: Broers Jan N. , Lemkowitz Saul M. , Van Berg Pieter J. Den 
Published: July 2010

AbstractThe densities of the urea synthesis solution in chemical equilibrium have been measured over the ranges 2.04 ⪕ NH3/CO2 ⪕ 6.3, H2O/CO2=0, 150 ⪕ T ⪕ Tcritical and Pbuble–point ⪕ P ⪕ 900 atm. In the temperature and composition range of, respectively, 150 ⪕ T ⪕ (Tcritical–20°C) and 2.7 ⪕ NH3/CO2 ⪕ 6.3, it is possible to describe accurately the experimental results by means of an empirical equation based on regression analysis. Experiments suggest that at high temperatures near critical conditions the chemical composition of the urea synthesis solution becomes a strong function of pressure.
Removal of radioactive strontium from water by coagulation–flocculation with ferric hydroxide
Authors: Bull Patrick S. , Evans John V. , Knight Ronald J. 
Published: July 2010

AbstractA systematic study of the removal of the radioactive fission product strontium from aqueous solution by ferric hydroxide flocs has shown that strontium can be removed effectively, in contrast to caesium which is poorly removed (⩽5%) under all conditions examined. Removal of strontium was enhanced by raising pH to a maximum of 10.5, increasing the iron/strontium ratio, or by adding phosphate ion, provided the phosphate/iron mole ratio did not exceed 0.33. In the absence of phosphate the optimum conditions for strontium removal, over the range of iron and strontium concentrations examined, were pH 10 and strontium/iron mole ratio 0.08. Addition of phosphate reduced the pH at which significant removal was obtained to about 8. The mechanism of removal has been identified as an ion‐exchange reaction at the surface of the ferric hydroxide particles; consequently, when considering the process for the removal of stron‐tium‐90 from hard natural or process waters competitive effects from the larger concentrations of calcium and magnesium present in the water would become important.
Some quantitative studies on light fading of after‐treated direct dyes
Authors: Shah Champaklal D. , Srinivasan Rajagopalan , Venkateshmurthy J. 
Published: July 2010

AbstractQuantitative measurements of increase in lightfastness of direct dyes on cellophane on after‐treatment with different metallic salts, e.g. sulphates of copper, cobalt, nickel, chromium and (ferrous) iron have been carried out. Copper sulphate has been found to be the best of all these salts. About 2% copper sulphate is found to cause considerable increase in the lightfastness. Measurements of y/x ratios of dyed and after‐treated cellophane and also slopes of CF curves have shown that the higher fastness is due to higher aggregation of the dye in the fibre on after‐treatment with copper sulphate. Metal complex formation with dye structures of the type o‐hydroxy‐o′‐methoxy (or o′‐hydroxy or ethoxy) azo has been found to be more useful for copper after‐treatment than complex formation with dyes with a salicylic acid residue.
Effect of pH on the retention of inorganic fillers
Authors: Jaycock Michael J. , Pearson Joseph L. 
Published: July 2010

AbstractThe effect of pH on the retention of various inorganic fillers has been studied. It is found that the isoelectric point of the filler has no effect on its retention characteristics with our particular sulphate bleached pulp. This is due to the fact that the surface of the filler is modified by either the adsorption of or the flocculation with the fines and colloidal material originating from the fibre surface. This surface modification produces a shift of the apparent isoelectric point of the fillers and in many cases gives rise to heteroflocculation of the fibres and filler particles only when the pH is at more acid values than 4.0.
Hardened slag–cement pastes of various porosities. III. Surface area in relation to pore structure
Authors: Mikhail Raouf Sh. , Abo‐El‐Enein Salah A. , Abd‐El‐Khalik Mohamed 
Published: July 2010

AbstractThe total surface areas, total pore volumes, and the distribution of pore surface and pore volume in pores of different sizes were determined on the hardened slag‐cement pastes. Adsorption isotherms of four different adsorbates, namely water, methanol, nitrogen and cyclohexane, were used for surface area and pore structure determinations. The results obtained indicated that water can penetrate into the total pore system, namely both the micropores and the wide pores; whereas methanol can measure wide pores and some of the micropores; moreover, nitrogen and cyclohexane molecules tend to measure only wider groups of pores. The indication gained from this result is that the molecular sieve property plays the most significant role in surface area and pore structure determinations of the hardened cement pastes. The polarity of the molecules seems to be important at low relative vapour pressures, and at high pressures it causes expansion of the pastes.
Alkane sulphonate preparation by the sulphitation of long chain olefins
Authors: Bright Samuel C. , Stubbs Christopher E. , Thompson Laurence 
Published: July 2010

AbstractThe free radical addition of sodium bisulphite to linear olefins (sulphitation) has been investigated. It was observed that the kinetic consequences of the probable mechanism of sulphitation were consistent with the experimental results. Thus sulphitation is first order with respect to olefin concentration and above a critical level is independent of bisulphite concentration. In the sulphitation of 1‐dodecene an undesirable alkane–sulphonate–sulphinate forms, the proportion of which, as expected, varies with sulphitation pH; the higher the pH the less the proportion of sulphonate–sulphinate. To prepare alkane sulphonates optimally thereby restricting the sulphonate–sulphinate proportion to an acceptable minimum (15% w/w) sulphitation pH should be the maximum at which the critical bisulphite concentration can exist. Further minimisation of sulphonate–sulphinate formation requires a new approach. It was found that whereas linear olefins give rise to this product, as does 1‐hexyne, vinylidene olefins, styrene and 1,3–hexadiene do not. These observations have been rationalised in terms of the relative thermal stabilities of the intermediate sulphone–sulphonate radicals.
Metallurgical characterisation of high resilience stainless steel orthodontic wires
Authors: Williams David W. , von Fraunhofer Joseph A. , Davies Edward H. 
Published: July 2010

AbstractNominally 0.4 mm diameter high resilience stainless steel orthodontic spring wires, as used in appliances (or braces) for the correction of children's malaligned teeth, are notoriously inconsistent in their clinical behaviour. This is principally due to a lack of compositional control and to the severe work hardening of the wire drawing process. A selection of the spring wires in clinical use has been investigated here to characterise them by means of spectrochemical analysis, tensile testing, potentiostatic polarisation, and ferromagnetic measurements. The study of these interrelating factors is suggested as a method of characterisation for the wires to ensure greater clinical consistency. The effects of bending and low temperature heat treatment on the wires have also been investigated.
Prediction of isobaric and isothermal vapour–liquid equilibria from limited experimental data
Authors: Khanna Ashok , Mukhopadhyay Mamata 
Published: July 2010

AbstractMalesinski's method for prediction of isobaric vapour–liquid equilibrium data using a single experimental datum on a T–x isobar has been modified and extended to a more general case where the molar entropies of vaporisation of the components are not necessarily equal and the non‐ideality in the vapour phase is considered. However, it is assumed that the solution behaves like a strictly regular one over the temperature range in question, that is, the constant A in the expression for excess free energy: gE=Ax1x2 is independent of temperature. The method has been illustrated for several systems and is found to be highly satisfactory for non‐polar–non‐polar as well as polar–non‐polar systems in which the boiling points of the pure components are not much different. Incorporating temperature dependence of the constants in the Redlich–Kister equation for excess free energy, a method has been developed for predicting isothermal vapour–liquid equilibrium data at several temperature levels from equilibrium values at a single pressure. For testing the validity of this method, predicted results have been compared with the available experimental data for zeotropic as well as azeotropic systems comprising non‐polar–non‐polar, polar–non‐polar and polar–polar mixtures, and the method has been found to be satisfactory for all systems.
Textural variations of acid‐treated serpentine
Authors: Girgis Badie S. , Mourad Wedad E. 
Published: July 2010

AbstractA natural serpentine deposit was subjected to treatment with hydrochloric acid of different concentrations, and for varying times. Changes in the texture parameters were determined from adsorption isotherms of nitrogen. In general, treatment with increasing acid concentrations (up to 25%) leads to an increase in various characteristics of serpentine, i.e. weight loss, dissolved iron oxide, “free” silica, surface area, and pore volume. Prolonged treatment results in only slight changes in such parameters. Solids of high specific surface areas (up to 300 m2/g) and of microporous character (mean pore radii ca 15–20 Å) are obtained.
Activation of platinum‐alumina catalysts for the hydrogenation of aromatic hydrocarbons
Authors: Aboul‐Gheit Ahmed K. , Cosyns J. 
Published: July 2010

AbstractA white spirit fraction was hydrogenated in a continuous flow microreactor unit, using 0.35% platinum‐alumina catalysts. These catalysts contained 0.0, 0.40 or 0.87% chlorine. Chlorination of the catalysts was carried out during the process of platinum impregnation. This treatment was found to enhance significantly the hydrogenation activity of the catalysts, and may be attributed to an improvement in the dispersion of platinum in the alumina support. Calcination of the catalysts before their reduction proved to be an important preparation step. Increasing the reduction temperature from 200 to 500°C considerably increased the catalytic activity. The activation energies obtained for hydrogenation of aromatics over catalysts reduced at temperatures between 200 and 500°C were found to range between 10.14 and 6.50 kcal mol−1. These energies were found to decrease, in general, with increasing chlorine content of the catalyst and with its reduction temperature. The variation in activation energy with the Arrhenius pre‐exponential factor, as a function of the catalyst reduction temperature, indicates that catalysts containing 0.40 and 0.87% chlorine follow the equation k0 = exp (‐3.25 + 0.001E), and hence their surface uniformity would be identical. However, unchlorinated catalysts, both calcinated before reduction or uncalcinated, exhibit considerably different surface uniformity.
Pressure effects in the infrared vibrational spectra of gaseous molecules
Authors: Corbett John K. 
Published: July 2010

AbstractA new semi‐empirical equation is proposed which predicts the extent of the observed spectral intensity enhancement caused by the effect of foreign gases on many infrared‐active gaseous molecules. The evolved expression has the form:Sv2μ−1=A exp {−B/(F+C)}Where S is a symmetry factor, v is the vibrational frequency (cm−1), μ is the reduced mass of the colliding pair, and F is the spectral enhancement factor for one atmosphere of foreign gas. A is a constant for a particular foreign gas, and B and C are general equation constants with values B = 18.5 and C = 1.5. Predicted and observed values of the enhancement factors are listed for a range of common gaseous molecules in the foreign gases nitrogen and helium. Suggested causes of the discrepancies between the calculated and experimental results are briefly discussed.
Increase of β‐glucanase production by Bacillus subtilis by use of starch feeding during fermentor cultivation
Authors: Markkanen Pertti , Reinwall Anneli , Linko Matti 
Published: July 2010

AbstractThe production of β‐glucanase by Bacillus subtilis VTT 160 was studied. Using a medium containing barley and distiller's grain the concentration of available sugars approached zero at the end of the phase of active production of β‐glucanase. For this reason starch feeding was employed, commencing at this stage of the cultivation. Markedly increased yields of β‐glucanase were obtained when the starch feed was commenced at the correct time.