bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conductance studies on sodium silicates
Authors: Lee C. K. , Dent Glasser L. S. 
Published: July 2010

AbstractSodium silicate solutions with silicon dioxide: sodium monoxide mole ratios of 3.41 : 1 and 3.98 : 1 were dried to form gels. Some conductance studies were carried out on the sodium silicate as it dried, and when the dried material was heated up to 160 °C. The results suggest that conduction is mainly due to sodium ions both in the solution and in the gel; to this extent the mechanism of con, duction is similar to that in sodium silicate glasses. However, the gel has a much higher conductance than a glass of similar Na2O : SiO2ratio, and this is probably because the gel contains hydroxyl ions and hydrated silicate ions, whereas the glass does not; moreover, the gel has a much less tightly packed structure than does the glass.
Flotation of α‐iron(III) oxide by cetyltrimethylammonium bromide and its activation by phosphates
Authors: Yousef Aziza A. , Bibawy Talaat A. , Malati Mounir A. 
Published: July 2010

AbstractThe zero point of charge, z.p.c., of chemically prepared α‐Fe2O3 was found at pH 6.9. The adsorption isotherms of cetyltrimethylammonium bromide, CTAB, had a Langmuir shape and shifted to higher adsorption density as the pH increased above the z.p.c. The variation of the adsorption plateau with pH could be correlated with the change in ζ potential accompanying the adsorption of CTAB. The graphs of the recovery of α‐Fe2O3 floated by CTAB plotted against its equilibrium concentration exhibited maxima, which became higher as the pH increased from 6 to 10. The adsorption capacity of α‐Fe2O3 for phosphate ions markedly decreased and their desorption increased as the pH increased. The drop in ζ potential of α‐Fe2O3 in phosphate solution became smaller as the pH increased. In presence of phosphate ions, the adsorption capacity of α‐Fe2O3 for CTAB markedly increased at pH 6, the enhancement becoming less marked as the pH increased. The enhancement paralleled the phosphate adsorption. In presence of phosphate ions, the recovery of α‐Fe2O3 floated by CTAB was higher, the activation decreasing as the pH increased. The maximum recovery was shifted to lower CTAB concentration compared to the recovery of unactivated α‐Fe2O3.
Control of well‐mixed biological reactors subject to variations in feed concentration and flow rate
Authors: Klei Herbert E. , Sundstrom Donald W. , Molvar Allen E. 
Published: July 2010

AbstractSeveral types of controllers on biological reactors were optimised to adjust the biomass recycle flow rate in response to step and sine changes in the feed concentration and feed flow rate. All controllers eliminated the error in the effluent substrate concentration except near the mid‐range frequency of 0.5 cycles residence time. Relay controllers gave results comparable with the more sophisticated types and are recommended for plant operation due to their simplicity.
Further studies on miscible oil
Authors: Souza Decio A. , Piedade José R. 
Published: July 2010

AbstractIn continuation of a previous paper some properties of the same type of miscible oil are studied. The subjects considered are: determination of the constant K (which is characteristic of the emulsifier); mixture of two miscible oils; exposure of the miscible oil to the atmosphere; liquids with which miscible oil could not be obtained and, finally, miscible oil containing an insecticide for use in agriculture.
Vapour synthesis: A new technique in synthetic chemistry
Authors: Young Dennis , Green Malcolm L. H. 
Published: July 2010

AbstractVapour synthesis is the use, as reagents, of vapours which are formed at high temperatures. Typically, vapours, such as those of transition metal atoms, are brought into contact on a cold surface with a substrate, for example an unsaturated hydrocarbon. The ensuing reaction can form compounds, typically organo‐transition metal complexes. The principles and methodology are discussed critically to show the applicability of this technique to synthesis and research. A review of recent research illustrating the scope of vapour synthesis is given.
Location of sodium incorporated in crystals of gypsum
Authors: King George A. , Ridge Mayhew J. , Walker Graham S. 
Published: July 2010

AbstractA study was made of the effects of variations in concentration (0.125–0.75 saturated) and temperature (3–50°C) on the amounts of sodium incorporated in crystals of calcium sulphate dihydrate formed by the hydration of calcium sulphate hemihydrate in solutions of sodium chloride. The incorporation of sodium was favoured by reducing the temperature and increasing the concentration of sodium chloride. Samples of dihydrate containing sodium gave X‐ray diffraction patterns with additional peaks that were attributed to the presence of a compound of calcium sulphate containing sodium but resembling the hemihydrate crystallographically. This compound appeared to occur as inclusions within the grains of dihydrate.
A new preparative method for cyclohexenyl alkenyl ketones
Authors: Watanabe Shoji , Fujita Tsutomu , Suga Kyoichi , Yokoyama Toshiro 
Published: July 2010

AbstractNew cyclohexenyl alkenyl ketones are prepared by the reaction of various methyl cyclohexenyl carboxylates and vinylmagnesium chloride; for example, 1‐(4′‐methyl‐3′‐cyclohexene‐1′‐yl)‐1‐oxo‐4‐pentene is obtained from methyl 4‐methyl‐3‐cyclohexene‐1‐carboxylate and vinylmagnesium chloride.
Synthesis of dipropylaniline from aniline and n‐propanol
Authors: Nandi Dilip K. , Bhattacharyya Asish K. 
Published: July 2010

AbstractA systematic study has been made of the synthesis of dipropylaniline from aniline and n‐propanol using H2SO4 and HCl as catalysts. With both catalysts, the optimum temperature, pressure, residence period, mole ratio of aniline to n‐propanol and mole ratio of aniline to H+ (catalyst) for the synthesis are 245°C, 600 lb/in2, 2 h, 1:3 and 1:0.305 respectively. Very high pressure has practically no influence on the reaction and it helps only to form undesirable tarry matter. The maximum conversions of aniline to dipropylaniline under these optimum conditions are 45.53 and 46.57% with H2SO4 and HCl respectively. The conversion of aniline to propylaniline is always found to be greater than conversion to dipropylaniline. At the optimum conditions for the synthesis of dipropylaniline, conversions of aniline to propylaniline are 47.75% with H2SO4 and 51.55% with HCl.
Inhibition of penicillin production by carbon dioxide
Authors: Pirt S. John , Mancini Biagio 
Published: July 2010

AbstractBy means of chemostat culture and automatic control of pH and dissolved oxygen tension the penicillin fermentation was controlled so that the partial pressure of carbon dioxide (Pco2) in the gas phase was the only variable. This reveals that under the conditions used carbon dioxide strongly inhibits penicillin production. The synthesis rate (units/mg dry mycelium x h) was decreased about 50% by a Pco2 of 0.08 atm.
Effect of alteration of aeration and temperature on production of α‐amylase by Bacillus subtilis
Authors: Markkanen Pertti H. , Bailey Michael J. 
Published: July 2010

Abstractα‐Amylase production by Bacillus subtilis in fermentation was markedly increased by reduction of aeration at the end of the exponential growth phase. The resultant decrease in pH seems to be a limiting factor and without pH control the aeration rate could be reduced from 1 litre/litre/min to 0.2 litre/litre/min for optimum α‐amylase production. Alteration of temperature at the same stage did not result in improved yields.
Surface area and pore structure of stannic oxide gel from organic vapour adsorption
Authors: Selim Suzy A. , Zeidan Farouk I. 
Published: July 2010

AbstractSurface area measurements were performed on stannic oxide gel and its thermal dehydration products obtained both in vacuo and in presence of air in the temperature range 100–600°C by benzene and carbon tetrachloride adsorption at 35°C. The presence or absence of air is found to impose changes in the surface area and consequently vary the pore structure of the solid material. Pore size analyses for both micro‐ and mesopores are performed. The low temperature samples are characterised by the presence of micropores only. At 350°C widening of pores commences and at higher temperatures the results indicate the existence of pores of “submicro” dimensions together with the mesopores. These changes in pore structure go in parallel with the gradual development of the crystalline cassiterite structure.
Crystallisation of pentaerythritol ii. growth inhibiting impurities
Authors: Clatworthy Brian , Rehmatullah Sikandra , Wahab Adnan B. A. , Creasy Dennis E. 
Published: July 2010

AbstractThe growth rate of pentaerythritol crystals from carefully purified aqueous solution has been measured in a fluidised bed. Very high growth rates were obtained of nearly the same order of magnitude as the estimated diffusion control limit of 10−6 m/s at 30°C and 0.025 mass fraction supersaturation. The growth rate was also measured in cells containing static purified solution to which specific impurities had been added. The only impurity which had significant effect in low concentrations was formaldehyde and it was found that 10 parts/106 reduced the growth rate by over two orders of magnitude. It was found that all the samples of commercial pentaerythritol analysed contained ≤20 parts/106 which on solution was more than enough to cause very serious growth inhibition. Chemical scavengering of this trace of formaldehyde is essential if reasonable growth rates are to be achieved in industrial crystallisers.
Studies on β‐alkoxypropionitriles as solvents for extractive distillation
Authors: Kuchhal Rakesh K. , Mallik Kanai L. 
Published: July 2010

AbstractFive solvents of the β‐alkoxypropionitrile series have been studied by gas‐chromatographyin order to examine their potential usefulness as solvents for extractive distillation. Four isomers of C4‐olefin and a diene were used as solutes for the determination of activity coefficients at infinite dilution at 30°C. Relative volatilities were calculated for these solvents and compared with those for other commercial solvents used currently. Relative volatilities of seven C4‐hydrocarbons in two solvents were also studied and compared with the existing literature data for β‐methoxypropionitrile containing 5% antisolvent. The present g.c. studies show that besides the well‐studied β‐methoxypropionitrile, the second member of the series, β‐ethoxypropionitrile, also has the potential for use as a selective solvent.
Variation of the specific surface area and porosity of anhydrous zinc oxalate with water vapour pressure
Authors: Mikhail Raouf S. H. , Guindy Nabila M. , Ali Ismail T. 
Published: July 2010

AbstractSpecific surface areas and pore structure studies were carried out on two sets of samples of anhydrous zinc oxalate prepared from the dihydrate by heating at 130 and 180°C in various atmospheres of differing water vapour pressure. The two sets of samples were freshly prepared and aged samples. The variation of specific surface areas with water vapour pressure was found to behave in accordance with the Smith‐Topley effect, with a minimum SBET value located at 3.0 mmHg of water vapour. Analysis of the nitrogen adsorption isotherms by the t‐method revealed the existence of both micropores and mesopores in the freshly prepared samples heated both at 130 and 180°C in 8.0 mmHg water vapour, and also in the aged samples prepared at 130°C in vacuo, and at 180°C in 8.0 mmHg water vapour. The rest of the samples possess only wide pores. Complete pore structure analysis for both micro‐ and mesopores was carried out for all samples investigated, and an attempt was made to correlate the factors affecting the development of surface area and pore structure, both in the presence and absence of water vapour, with those affecting the dehydration rate, and which occasionally lead to the Smith‐Topley effect.
A rapid attenuated total reflectance infrared method for tolylene diisocyanate isomer ratio determination
Authors: Corbett J. K. 
Published: July 2010

AbstractAn attenuated total reflectance (ATR) infrared method is described for the determination of the 2,4‐/2,6‐isomer ratio in tolylene diisocyanate. The absorption band intensity ratio at 1076 cm−1 (2,4‐isomer) and 780 cm−1 (2,6‐isomer) is measured.
Purification of carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae
Authors: Abou‐Zeid Abou‐Zeid A. , Shehata Yousef M. , Madi Ahmad G. , El‐Sherbiny Adel , El‐Nagar Ahmad A. , El‐Hafez Kamal Abd 
Published: July 2010

AbstractThe impurities present in carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae were mainly acetaldehyde and butyraldehyde. 2,4‐DNP reagent was sensitive to these impurities and they were precipitated as hydrazones. The soluble volatile organic compounds were completely removed in washers (I and II). The other impurities present in carbon dioxide were removed by treating the gas with potassium permanganate and activated charcoal to obtain pure gas. The system used in the purification of carbon dioxide in the factory was efficient when washing water was sufficient (2400 litres of running water/h) and the potassium permanganate solution was changed when it was exhausted.
Polyol surfactants derived from moringa seed oil for potential use in the pharmaceutical industry
Authors: Sengupta Anupam , Basu Saumyapriya P. 
Published: July 2010

AbstractTwo polyol surfactants ((a) a crude product of 60% monoglyceride content and (b) a homogeneous sorbitan ester) have been prepared by alcoholysis from the not well known edible Moringa concanensis seed oil. These products constituted mainly oleic acid, which will be suitable for utilisation in the pharmaceutical industry. The optimum conditions of glycerolysis of the moringa seed oil have also been found.
Long‐chain alkyl phthalic acids and their derivatives
Authors: Carson Phillip A. , Lapper Mark 
Published: July 2010

AbstractThe synthesis of alkyl phthalic acids by the oxidation of alkyl ortho‐xylenes is described. The evaluation of their derivatives as detergent actives (surfactants), builders (water softeners), fabric‐softeners and as PVC plasticisers is discussed. A brief mention is made of some aspects of their biodegradation.
Thermal decomposition and pore structure of pure and doped stannic oxide gel
Authors: Mikhail Raouf S. H. , Selim Suzy A. , Zeidan Farouk I. 
Published: July 2010

AbstractThe surface properties of a stannic oxide gel and its thermal dehydration products obtained both in vacuo and in the presence of air in the temperature range 100–600°C have been examined by N2 adsorption. Phase and structural changes have been followed by differential thermal analysis and X‐ray diffractometry. Complete pore structure analysis showed that samples dehydrated at or below 250°C were microporous. Above 250°C the pores were found to widen with increase of temperature, the widening occurring concurrently with the crystallisation process. Doping with cations of lower valency (Li+ and Al3+) than the host cation (Sn4+) had little effect on the pore structure and specific surface area for the low temperature samples (≥250°), whereas at higher temperatures, e.g. 600°C, it increased the specific area remarkably. The dope ions produce oxygen vacancies and hinder or retard sintering in SnO2.
Variation of the specific surface area and porosity of zinc oxide prepared in various atmospheres
Authors: Mikhail Raouf SH. , Guindy Nabila M. , Ali Ismail T. 
Published: July 2010

AbstractSpecific surface area and pore structure studies were carried out on zinc oxide samples prepared from zinc oxalate dihydrate by heating at 330 and 370°C and in various atmospheres of water vapour, oxygen and hydrogen. The variation of SBET with water vapour pressure for the samples heated at 330°C was found to show a behaviour which can be compared with the Smith‐Topley effect. For the samples prepared at 370°C, rapid sintering occurred, and the Smith‐Topley effect was not followed in this case. Zinc oxide prepared in an oxygen atmosphere gave higher surface area values than that prepared in a hydrogen atmosphere, which is thought to be due to the oxidation of the carbon impurities on the surface. Analysis of nitrogen adsorption isotherms by the t‐method revealed the existence of micropores in the sample prepared at 330°C in vacuo. The rest of the samples have wide pores.
Impurity deposition from an evaporated solvent and its effect on steel oxidation
Authors: Emsley Alan M. , Hill Malcolm P. 
Published: July 2010

AbstractIt is shown that the evaporation of an organic solvent from a solid surface can result in the concentration of dissolved or suspended impurities at specific sites. Concentric ring patterns of the contaminant, which remain on the surface when evaporation is complete, can be explained by analogy with the spreading of liquid films. Trace hydrocarbon impurities can be concentrated on mild steel surfaces in this way, giving similar ring patterns in the early stages of the oxidation reaction in high pressure carbon dioxide atmospheres. Excessive localised oxidation occurs leading to the early development of oxide nodules.
Infrared measurement of total fatty acids in blood serum
Authors: Quintard Bernadette , Desbals Pierrette , Quintard Pierre 
Published: July 2010

AbstractQuantitative determination of total fatty acids in rabbit blood serum is achieved using the infrared absorption band, associated with the C = O stretching vibration at 1713 cm−1 (5.84 μm). Different tests are described to show the validity of this method for a wide range of variation in total concentration and in individual percentages of any one fatty acid. The results are treated by statistical methods, and it is found that infrared analysis is five times more sensitive than methods described previously. This accurate technique, which can be applied to other serums has, for example, been applied to disclose a systematic error in the preparation of total fatty acid samples when nitrogen flushing is not used.
A kinetic study of the reaction between terephthalic acid and ethylene oxide at atmospheric pressure
Authors: Bhatia Subhash , Rao M. Gopala , Rao M. Someswara 
Published: July 2010

AbstractThe kinetics of the reaction of terephthalic acid with ethylene oxide, in n‐butanol solvent, catalysed by triethyl amine, were investigated in a semi‐batch reactor under atmospheric conditions. It was found that the reaction occurred in the liquid phase and that mass transfer effects were absent. The reaction was found to be pseudo‐zero order in terephthalic acid and first order in ethylene oxide and in catalyst concentration. The effects of reaction temperature, catalyst concentration, particle size of terephthalic acid, ethylene oxide flow rate, stirrer speed and terephthalic acid to ethylene oxide ratio were studied. Particle size of terephthalic acid, stirrer speed and flow rate of ethylene oxide did not affect the reaction rate. The Arrhenius activation energy of the reaction was found to be between 19.2 and 23.5 kcal/mol.
An examination of sodium substitution in tricalcium aluminate by infrared absorption spectroscopy
Authors: Varma Satya P. 
Published: July 2010

AbstractThe replacement of CaO by Na2O in C3A has been studied by infrared spectroscopy. At up to 2.06% Na2O, C3A bands are slightly displaced indicating the existence of a solid solution. From 3.9 to 4.8% Na2O, the spectrum is largely modified and a different pattern with vibrations at 730, 790 and 872 cm−1 is observed. At 4.8–6.0% Na2O there is little further change, but the band at 872 cm−1 is broadened. It is proposed that modifications with 3.9–6% Na2O can be represented more adequately by the formula NC14A5 (4.57% Na2O) rather than NC8A3 (7.59% Na2O). Above 6% Na2O, other compounds such as free CaO, N2C3A5 and NA are also formed.
Electrolytic oxidation of chromium salts
Authors: Kuhn Anselm T. , Clarke Robert 
Published: July 2010

AbstractThe electrolytic oxidation of chromium salts is a reaction of both real and potential importance, both in the chemical process industries and also in the metal finishing and electronic industries. The literature, which is mainly of Russian origin, has now been made available in English for the first time. Published work is critically reviewed, and largely reinterpreted in the light of recent advances in the theory of mass‐transport together with experimental data in this field now available. The effects of electrode material, temperature, concentration, as well as foreign ions are considered in turn. Modern cell design has resulted in higher throughputs and lower energy costs. These are discussed. The mechanistic implications of the findings are considered.
Studies on cyanine dyes. III. Synthesis of 2‐styryl‐5‐cyanonaphthoxazole cyanine dyes
Authors: Osman Abdel‐Megied , Khalil Zarif H. , Kalaf Ali Ali , Ibrahim Ahmed 
Published: July 2010

AbstractNew types of styryl cyanine dyes (V) containing two different heterocyclic nuclei were prepared through the reaction of 5‐cyanonaphth[1,2‐]‐oxazole‐2‐carboxaldehyde (IV) with α‐picoline and quinaldine ethiodides. Other styryl bases (III) were also obtained as reaction products between 2‐methyl‐5‐cyanonaphth[1,2‐d]oxazole (I) and aromatic aldehydes in the presence of anhydrous zinc chloride. Structural configurations of the synthesised compounds were identified by u.v. and i.r. spectra determination.
Bagasse pulping by the soda‐nitrobenzene process
Authors: Saleh Tharwat M. , Fadl Mohammed H. , El‐Ashmawy Ahmed E. , El‐Meadawy Soheir A. 
Published: July 2010

AbstractBagasse was pulped by soda‐nitrobenzene liquor with various cooking parameters. High alkali charges and cooking temperatures caused the delignification reaction to proceed very rapidly, particularly during the initial phase which terminated in 15 min. The most advantageous effect of nitrobenzene addition was the stabilisation of the carbohydrate fraction against the peeling off reaction. All nitrobenzene pulps were characterised by increased pulp yield and decreased lignin content. The strength properties of all nitrobenzene pulps were function of temperature. Only at lower temperatures were the nitrobenzene pulps superior to the corresponding soda pulps.
Nitration of 1‐dodecene with nitric acid
Authors: Gregory Donald P. , Martens Rudolf J. , Stubbs Christopher E. , Wagner John D. 
Published: July 2010

AbstractA refluxing, heterogeneous mixture of l‐dodecene with aqueous 30% nitric acid leads to a mixture of closely related nitroproducts in greater than 90 % yield within 3 h. Similarly various types of readily available olefins easily undergo nitration with nitric acid. The nitration of l‐dodecene with nitric acid is initiated by nitrous acid, exhibits free‐radical character and is believed to proceed through the agency of nitrogen dioxide although the manner of its propagation is not fully clear. However, a rate‐determining oxidation step apparently determines both the variation of nitration time with change in olefin structure and also the temperature dependence of the rate of nitroproduct formation. Emulsifying agents increase the nitration rate and the slow addition of sufficient nitrous acid obviates the reaction's temperature dependence.