bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple method for the estimation of purine and pyrimidine bases in n‐alkane grown yeasts
Authors: Erskine Richard L. , Steedman Thoma S. A.
Published: July 2010

A method is described for the estimation of purine and pyrimidine bases on n‐alkane yeasts which employs a simple hydrolysis step with hot 72% perchloric acid followed by separation of the bases by ion‐exchange chromatography. The level of RNA in a sample can be calculated from the amounts of the bases present. The method is believed to be more precise and reliable than other methods employing extraction and u.v. spectrophotometric measurements.
Reactions of acetylene and ammonia in a continuous‐flow microwave discharge reactor
Authors: Brooks Brian W. , Spearot Rebecca M.
Published: July 2010

Both pure acetylene and mixtures of acetylene and ammonia have been passed continuously through a microwave discharge reactor. The reaction products from the gas mixtures were hydrogen cyanide, hydrogen and nitrogen. When the input reactant ratio (ammonia to acetylene) was below a critical value, the extent of reaction was negligible. When the critical ratio was exceeded, high conversions were obtained. When reaction did occur, the conversions of both reactants were linear functions of the power absorption in the discharge. The conversion of acetylene to hydrogen cyanide varied linearly with the input volumetric flow rate. Comparison of the present work with previous studies shows that hydrogen cyanide is not produced exclusively by the route

when mixtures of benzene and ammonia react in a microwave discharge.
Arylmercury compounds. III. Poly(arylmercury) compounds via symmetrisation reaction
Authors: Halpern Yuval , Garti Nissim
Published: July 2010

Dimercurated aryl compounds [Ar(HgX)2] are converted either to linear or cyclic poly(arylmercury) compounds. The reaction is carried out in a mixture of water and organic solvent via the symmetrisation process in which ethylene‐diaminetetraacetic acid (EDTA) and ammonia serve as chelating agent and auxiliary ligand, respectively. Similarly, mercury‐crosslinked polystyrene is obtained by applying the process for polymercurated polystyrene.
Conductance studies on sodium silicates
Authors: Lee C. K. , Dent Glasser L. S.
Published: July 2010

Sodium 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

The 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

Several 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

In 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

Vapour 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

A 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

New 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

A 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

By 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

α‐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

Surface 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

The 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

Five 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

Specific 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

An 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

The 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

Two 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

The 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

The 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

Specific 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

It 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

Quantitative 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

The 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

The 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

The 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

New 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

Bagasse 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

A 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.
Ion‐exchange properties of some brown seaweeds from the indian coast
Authors: Mehta B. R. , Baxi D. R.
Published: July 2010

Ion‐exchange properties of five marine algal species, viz. Sargassum tenerrimum J. Ag., S. swartzii (Turner) C. Ag., Cystoseira indica (Thivy et Doshi) Mairh, Tur‐binaria conoides (Kuetz) and Padina pavonica (L) (Thivy et Taylor) have been studied and compared with those of alginic acid. The ion‐exchange property of these samples is found to be due mainly to their alginic acid and fucoidin content. Uptake of calcium ions from different solutions and pH titration studies have revealed that the ionogenic groups present in the samples are dissociated to the extent of 35–50% even in neutral media. When subjected to continuous use, the ion‐exchange capacity of the weeds at first decreases but attains a constant value after a few cycles. The rate of exchange (H+→Na+ and H+→Ca2+) on these samples has also been investigated. Distribution coefficients (Kd) of some of the metal ions for the said species have also been determined and the affinity sequence of the metal ions for each of the samples has been given. Na+→Ca2+ and Na+→Mg2+ exchange equilibria gave abnornal exchange isotherms. However the separation factor 7alpha;Ca2+ is found to be an exponential function of the concentration ratio of the Na+/Ca2+ in the solution.
Improved power supply unit and current regulator for glow discharge electrolysis
Authors: Denaro Alfred R. , Davies Norman J. , Wood Alexander , Almubarak Mehdi A.
Published: July 2010

An improved combined rectifier and current regulator circuit for use in glow discharge electrolysis is described. Initiation of electrolysis will be obtained normally by switching on the primary high voltage supply and restricting the initial discharge current to less than 750 μA. As soon as this current is indicated, the required preset stabilised current can be switched on and accurately timed. Precise stabilisation of the current enabled the quantity of electricity passed in very short electrolyses to be measured with accuracy.
Thermal decomposition of iron sulphates. II. Mechanism of isothermal decomposition of FeSo4·H2O in carbon monoxide
Authors: Huuska Matti , Koskenlinna Markus , Niinistö Lauri
Published: July 2010

Thermal decomposition of FeSO4·H2O in carbon monoxide has been studied at 400–550°C by isothermal experiments. The reaction intermediates and products were identified by X‐ray diffraction and Mössbauer spectrometry and determined quantitatively by chemical analyses. In addition to the primary reduction of iron(II) sulphate to sulphide, a competing solid‐state reaction between FeS and FeSO4 takes place, leading to a loss of sulphur which amounts to about 25% at 420–460°C and to over 60% at 550°C. The final reaction products consist mainly of iron(II) sulphide and elemental iron. Enthalpies of the decomposition reactions are also briefly discussed.
The low gas flow rate foam separation of cerium (III) from dilute aqueous solutions
Authors: Shakir Kamal , Aziz Mourad
Published: July 2010

Two low gas flow rate foam separation techniques, ion and precipitate flotation, have been investigated for the separation of trivalent cerium from solutions with initial cerium concentrations ranging from 1 × 10−8 to 1 × 10−4M in the pH range of 1.8–12 using the anionic collector sodium lauryl sulphate and the cationic surfactant cetyl trimethyl ammonium bromide. In addition to the type of collector, the pH and the cerium ion concentration, and other factors which can affect flotation results, viz. the time period of bubbling, the rate of gas flow, the ageing of both the cerium and the collector ions, the ionic strength, and the concentration of the collector ions have been investigated and optimum conditions have been established. Under optimum conditions removals as high as 98.5% can be achieved.
Thermal treatment of Aerosil OX50: Pore structure and heats of immersion
Authors: Mikhail R. Sh. , Khalil A. M. , Nashed S.
Published: July 2010

Degussa Aerosil OX50 was thermally treated in vacuo, in the temperature range 20–1000°C. Effects of thermal treatment on the water contents, specific surface areas, pore structure and heats of immersion in water were investigated and discussed. Thermogravimetric analysis was used to select the temperatures of thermal treatment which reflect the various textural changes resulting from the heat effects. It could be shown that the heats of immersion in water depend on both the water content of the sample (molecular water and/or surface hydroxyls) and on the surface texture of the silica gel, that is, the pore structure. The interesting result obtained is that the heat of immersion in water is partly proportional to the mesopore fraction of the surface. Micropores lead to a decrease in the heat of immersion in water.
Grindability of some additions and its significance in the production of mixed cements
Authors: Hanna Kaissar M. , Afify Aly
Published: July 2010

Grinding tests were conducted in a laboratory steel ball mill, to investigate the grind‐ability of some natural and artificial materials as “additions” for incorporation in Portland cement. Strength tests were performed on mixed cements composed of 71% Portland cement clinker, 25% addition and 4% gypsum. In one series of experiments, the components of the mixed cement were separately ground and in another one they were simultaneously ground. It was found from surface production curves and from compressive strength data that when materials which are harder to grind than clinker such as sand are interground with clinker, the resulting cement develops higher early strength than a corresponding cement in which the pozzolanic addition is softer than clinker. For materials which are softer to grind than clinker, separate grinding of the cement components is better than combined grinding, particularly for the development of early strength.
Effect of moisture content of raw materials on the viscosity of limestone–marl slurry
Authors: Hanna Kaissar M. , Gamal Ahmed El
Published: July 2010

Viscosity measurements were performed to investigate the effect of moisture contained in Portland cement raw materials on the flow characteristics of limestonemarl slurry. Under conditions of constant total water content, the fluidity of the slurry increased as the moisture content of the raw materials decreased. The effect of moisture content of the raw materials becomes significant on reducing the water content of the slurry. In the presence of slurry thinners, the extent of deflocculation is greater with the raw materials of lower moisture content.
Studies on sodium silicate solutions by the method of trimethylsilylation
Authors: Glasser Lesley S. Dent , Lachowski Eric E. , Cameron G. Gordon
Published: July 2010

The method of trimethylsilylation was used to study anion distributions in sodium silicate solutions with Na2O: SiO2 ratios of 1:1 and 1:3.41 at various concentrations. The polysiloxanes produced were characterised, mainly by g.l.c., g.p.c. and C and H analyses, to give a picture of the anion distribution in the original solution. The results were compared with those from previous studies. The observations of earlier workers—that the degree of polymerisation increases with increasing concentration and decreasing soda:silica ratio—were confirmed.
Production of food yeast from whey ultrafiltrate by dialysis culture
Authors: Lane Alan G.
Published: July 2010

Yeast (Kluyveromyces fragilis) concentrations up to 90 g dry weight/litre were obtained by dialysis culture in an 8 litre fermenter and the concentrations of lactose in the whey ultrafiltrate reservoirs were reduced to 5–8 g/litre during the cultivation period. A marked and progressive fall in cell yield was observed as the concentration of yeast increased. Modelling experiments indicated that this fall was consistent with the effects of maintenance energy requirements and that the effect could be minimised by a four‐fold increase in the rate of dialysis. The feasibility of achieving the required increase with improved membranes was confirmed in experiments in which the rate of dialysis using existing membranes was shown to be doubled by either prior enzymic hydrolysis of the lactose or by doubling the membrane area.
Electrogenerative chloro‐ and bromo‐fluorination of olefins from aqueous media; the electrogenerative cell as a chemical reactor
Authors: Langer Stanley H. , Miller Alan D. , Pietsch Stephen
Published: July 2010

Fluoride ion can be discharged in conjunction with chloride and bromide ions under electrogenerative conditions at catalytic porous platinum electrodes to give dihaloalkanes. The cell C2H4(g), Pt black|KF, KCl (aq, barrier electrolyte)|Pt black, Cl2(g) gave 2‐chloroethanol, 1,2‐dichloroethane and 1‐chloro‐2‐fluoroethane (I); a similar cell gave 1‐bromo‐2‐fluoroethane (II) and analogous products with a platinum or carbon black anode and fluoride‐bromide electrolyte. While the yield of fluorinated compounds is low, they are prepared under very mild conditions. The electrogenerative cell can be operated to yield a variety of halogenated products in addition to (I) and (II).
Estimation of productivities in repeated fed batch cephalosporn fermentation
Authors: Trilli Antonio , Michelini Verardo , Mantovani Vera , Pirt S. John
Published: July 2010

The theory of fed batch culture was tested on the cephalosporin C fermentation. In repeated fed batch culture a constant fraction of the culture volume is removed at fixed intervals. Since the productivity (output rate/unit volume) and specific rate of product formation may vary throughout the fed batch cycle, an “average productivity” and “average specific rate of product formation” which describe the overall behaviour of the system over several cycles are introduced. The test shows that the quasi‐steady state of cephalosporin production predicted by fed batch theory can be maintained during at least 3.6 culture volume changes. The fed batch method of culture increased the productivity of the culture about 1.3 times with respect to that of simple batch culture whilst the cephalosporin C concentration was about the same in each type of culture.
Study of thermochromic behaviour of some indolinobenzospiropyrans by infrared spectroscopy
Authors: Bertoluzza Alessandro , Concilio Carlo , Finelli Paola
Published: July 2010

The thermochromic behaviour of some indolinobenzospiropyrans was studied by heating solid compounds in K Br. Changes in i.r. spectra are interpreted as being due to the formation of a pseudoquinonic structure, (V).
Thermal conductivity and viscosity of normal C2–C6 aliphatic carboxylic Acids
Authors: Kynaston Walter , Martin John F.
Published: July 2010

Equipment for measurements of thermal conductivity and viscosity of liquids in the temperature range 273–350 K and at atmospheric pressure is described. The thermal conductivity and viscosity of acetic, propionic, butyric, valeric and hexanoic acids in the liquid state have been measured. The values obtained are compared with published data and the ratio of thermal conductivity, λ, to viscosity, η, is examined in the form of the dimensionless quantities, Mλ/Rη and cpη/λ (Prandtl number).
A phase model for the gas–liquid equilibria in the ammonia–carbon dioxide–water–urea system in chemical equilibrium at urea synthesis conditions. II. Experimental verification
Authors: Lemkowitz Saul M. , Vet Eric , van den Berg Pieter J.
Published: July 2010

Bubble‐ and critical‐points in the ammonia–carbon dioxide plane and ammonia–urea system are presented as well as bubble‐points in the carbon dioxide–urea system. In order to confirm the form of a previously presented phase model a large number of bubble‐ and dew‐points were measured at various ammonia–carbon dioxide–water–urea compositions (including those most important to the urea industry) in the range of 140 ⩽T⩽ 200°C and 15 <P< 400 atm. All of the measurements were carried out under conditions of complete chemical equilibrium. The results are in agreement with the ternary phase model presented in a previous article.
A phase model for the gas‐liquid equilibria in the ammonia‐carbon dioxide‐water‐urea system in chemical equilibrium at urea synthesis conditions. III. Comparison of the phase model with an empirical thermodynamic model
Authors: Lemkowitz Saul M. , Verbrugge Peter , van den Berg Pieter J.
Published: July 2010

Calculations using an empirical thermodynamic model for the ammonia‐carbon dioxide‐water‐urea system in chemical equilibrium lead to phase equilibria results consistent and in good agreement with those following from a previously published ternary phase model for this system.
Coating of finished flax particle boards with insoluble gelatin
Authors: Fadl Naim A. , Sefain Magdi Z.
Published: July 2010

Coating of finished flax particle boards with gelatin only, did not improve the resistance of boards to hot water. Coating with gelatin rendered insoluble, however, using hexamine and high temperature produced an insoluble gelatin film on the flax particles, which improved water resistance of the coated boards. Particle boards coated with 5% gelatin and a high concentration of hexamine (10%), improved water resistance to about 50% higher than that of uncoated samples. Higher amounts of gelatin (7.5 and 10%) gave a smaller improvement. The changes in thickness and density of the coated samples were also investigated.
Preparation of tricalcium phosphate by hydrolysis of dicalcium phosphate with calcium hydroxide
Authors: Bhavnagary Haiderali M. , Venugopal Jagadapur S. , Majumder Suvendu K.
Published: July 2010

A hydrolysis reaction between dicalcium phosphate and calcium hydroxide has been investigated for the formation of tricalcium phosphate. It decreased steadily with the increase in aqueous dicalcium phosphate slurry concentration in the range of 0.5 to 1.25% under steam pressures of 5–25 lb/in2 and attained equilibrium at the concentration of 1.25% aqueous dicalcium phosphate. During the initial period of 2 h, the hydrolysis proceeded gradually to the respective maximums at the steam pressures of 15 and 25 lb/in2 and thereupon it was constant. It was also shown that 28.33% excess above the stoichiometric quantity of the hydrolysing agent, calcium hydroxide, was necessary for the complete hydrolysis to occur at the steam pressure of 25 lb/in2 for the aqueous suspensions of 5 and 25% dicalcium phosphate. The effect of increasing steam pressure showed that a complete conversion of dicalcium phosphate to tricalcium phosphate could be obtained at a steam pressure of 51.5 lb/in2 for any concentration of aqueous phosphate slurry.
Determination and correlation of diffusion coefficients of some dyes in organic solvents of high viscosity
Authors: Warren Brian C. H. , Pattle Richard E.
Published: July 2010

Diffusion coefficients of three dyes at low concentrations in a range of liquids of different viscosities have been measured by a capillary method, and the validity of various empirical equations for predicting diffusion coefficients has been assessed. The inverse relationship between diffusion coefficient and viscosity was found to apply only in mobile liquids, the product Dη being greater in viscous liquids. For a given viscosity, the difference between predicted and experimental values was greatest for hydrogen‐bonded liquids. Comparison with other results suggests that the diffusivity varies inversely as some power of the molar volume of the solute, the exponent varying from about 0.7 for mobile liquids, through 1.1 to 1.4 for viscous liquids, to a literature value of 1.7 for solid rubber.
Ce(III), Th(IV) and U(VI) chelates of alizarin viridine, alizarin heliotrope and alizarin maroon
Authors: Idriss Kamal A. , Issa Issa M. , Seleim Mohamed M.
Published: July 2010

The complexes of 7,8‐dihydroxy‐1,4‐di(2′‐sulpho‐4′‐methylanilano)anthraquinone (alizarin viridine); 1,4‐dihydroxy‐2(2′‐sulpho‐4′‐methylanilino)anthraquinone (alizarin heliotrope) and 3‐amino‐1,2‐dihydroxyanthraquinone (alizarin maroon) with Ce(III), Th(IV) and U(VI) have been investigated using spectrophotometric and conductometric methods. The study revealed the formation of complexes having the metal: ligand ratios 1:1 and 1:2. The values of log β* for the different complexes are determined. The structure of the ligands in the solid chelates were studied by i.r. spectrophotometry which showed that chelate formation takes place through the CO and neighbouring OH group and leads to proton displacement.
Effect of various steps of purification on ash content and ash constitution of cellulose. II. Cellulose prepared from sugar‐cane bagasse
Authors: Shahine Salah , El‐Shorbani Salah , El‐Sadani Mohamed
Published: July 2010

The effect of the various steps of purification on the ash content and ash constitution of cellulose prepared from bagasse has been examined. After each step of purification, samples were analysed for total ash, SiO2, Ca, Fe and Mn. Two schemes of purification have been investigated. The first involves acid prehydrolysis, alkaline pulping and bleaching, and the second water prehydrolysis, acid pulping and bleaching. The first scheme has a better effect in diminishing the ash content, and gives a pulp containing 95.8% alpha cellulose with a 90% degree of whiteness.
Controlled pyrolysis of maleic hydrazide
Authors: Smith Walter T. , Mayer Charles F. , Kook Chyung S. , Patterson John M.
Published: July 2010

Maleic hydrazide (MH) has been pyrolysed at 600°C in our controlled pyrolysis apparatus. During pyrolysis volatile compounds distil out ahead of the moving heated zone and are not extensively repyrolysed, while those substances which are absorbed by pyrolysand or are relatively nonvolatile are repyrolysed. Also, reactive intermediates can react with one another or with unpyrolysed material. Pyrolysis products determined include CO2 (24 wt%), CO (2 wt%), HCN (3 wt%), NH3 (9 wt%) and N2 (3 wt%). The gases identified account for 41 % of the maleic hydrazide pyrolysed. An additional 50% of the material pyrolysed remains as a black solid having the approximate composition C15H15N5O2. Approximately 1 % of the maleic hydrazide is unchanged. Thus, the fate of 92% of the maleic hydrazide can be accounted for. A trace amount of hydrazine could be detected. The results obtained using controlled pyrolysis are compared with results obtained by us and others using different pyrolytic conditions.
Determination of the O2 and CO2KLa values in fermenters with the dynamic method measuring the step responses in the gas phase
Authors: Schneider Kurt , Frischknecht Kurt
Published: July 2010

Simulation studies using the mass balance equations demonstrate that it is possible to determine the KLa values for O2 and CO2 from measurements taken in the gas phase. In order to do this, the step change must be applied to the concentrations in the liquid phase. An injection device was developed to generate these step functions. The KLa values for O2 and CO2 measured in the presented system are of the same size. These values allow the theoretical step responses to be calculated, which are compared to the experimental ones. It is shown that the gas phase dynamic must be taken into account to avoid calculating KLa values with intolerable errors.
Saccharification of bagasse pith
Authors: Nee Charles I. , Yee Wen F.
Published: July 2010

Work is reported here on a process for the saccharification of bagasse pith, as the second part of a study of bagasse processing aimed at establishing an integrated industry. A method for pentose preparation from bagasse pith is designed on the basis of the conclusions reached in the first part of the study. It is preferable to Scholler's process in recovery of sugar and in concentration of the sugar solution. A process for glucose production from pentose‐exhausted cellulosic residue is also developed to avoid the difficulties encountered in the Udic‐Rheinau process. It seems to be a promising continuous process capable of giving a higher yield of glucose with less acid at a higher speed and affording favourable conditions for crystallising the dissolved glucose.
Voltage gradient and resolution in zone electrophoresis
Authors: Ewart J. A. D.
Published: July 2010

A theoretical equation connecting resolution in zone electrophoresis with other variables has been derived, and, in particular, resolution has been shown to be approximately proportional to the square root of the potential gradient. Some common troubles affecting resolution in zone electrophoresis are illustrated.
Aspects of microbial physiology in relation to process control
Authors: Leegwater M. P. M. , Neijssel O. M. , Tempest D. W.
Published: July 2010

The innate ability of microorganisms to respond rapidly to changes in the growth environment has been termed ‘reactivity’ and is a property of most microbial species. This feature of microbial physiology is of importance in the culturing of microbial cells on a large scale where environmental heterogeneity is unavoidable and gradients of temperature, pH, oxygen and nutrient concentration can occur. To assess the consequences of such gradients, a study was made of the influence of a discontinuous addition of glucose to a glucose‐limited chemostat culture of Klebsiella aerogenes. Results revealed a marked and unexpected shift in metabolism with an increased capacity for glucose uptake and respiration. This increased reactivity enhanced the ability of K. aerogenes to compete with other species (e.g. Escherichia coli) in chemostat culture.
Development of downstream processing
Authors: Atkinson Bernard , Sainter Philip
Published: July 2010

Foreseen developments in biotechnology are likely to lead to a proliferation of processes for small‐tonnage products and a number of large‐scale operations providing alternatives to natural and petrochemical‐based products. Product recovery will become increasingly important and, possibly, a dominant factor in the overall cost. The primary stages of the recovery processes must handle dilute slurries from the fermenter at a low cost per unit slurry volume if the overall processes are to be economical. Available unit processes are identified and the type of developments likely to prove economical are discussed. Subsequent recovery stages are much more closely related to established process‐engineering technology and in this area the key decision is likely to be the choice of the most appropriate route from the alternatives which are available. Equipment development to bring some laboratory separation techniques to a production scale will probably be required.