bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pullulanase synthesis in klebsiella aerogenes growing at high biomass levels in maltose‐limited chemostat culture
Authors: Hope Geoffrey C. , Dean Alastair C. R. 
Published: July 2010

AbstractThe effect of increasing the culture biomass on pullulanase synthesis in Klebsiella aerogenes NCIB 5938 was studied. Provided adequate aeration was supplied the steady‐state pullulanase specific activity and the biomass could both be maintained at their optimum levels but the higher the biomass the smaller the proportion of enzyme which remained firmly cell‐bound. A sudden change from aerobic to anaerobic conditions caused the release of more enzyme from the organisms but on continued anaerobic culture both the total enzyme activity and the proportion which remained cell‐bound returned to their aerobic values. In contrast, neither cell‐bound nor cell‐free pullulanase was induced when anaerobiosis was maintained from the start.
Kinetics of gaseous reduction of ilmenite
Authors: Jones David G. 
Published: July 2010

AbstractNatural Australian beach sand ilmenites and their preoxidised derivatives were reduced to metallic iron and titanium oxides by carbon monoxide at temperatures in the range 800–1200 °C. Particular care was taken to maintain a constant driving force for reduction using small samples and high gas flow rates. Over the entire temperature range studied, the natural minerals were found to reduce more rapidly than the corresponding preoxidised materials, although preoxidation was found to improve the extent of metallisation of the product. Heating the natural minerals in an inert atmosphere prior to reduction decreased their reactivities by approximately 70%. It is suggested that at temperatures below about 900 °C the reduction is controlled by the chemical reaction rate, but that a transport‐controlled mechanism gradually takes over as the temperature is increased. At 1000 °C the reduction is apparently controlled by diffusion of carbon monoxide through the external gas film. With increasing temperature above about 1050 °C, when the reaction mass begins to sinter, the reduction rate decreases.
Thermal decomposition of nickel hydroxide
Authors: Sato Taichi , Nakamura Takato , Ozawa Fusazi 
Published: July 2010

AbstractThe thermal decomposition of nickel hydroxides prepared from aqueous nickel chloride solution on addition of alkali under various conditions has been examined by thermogravimetry, differential thermal analysis, X‐ray diffraction study, visible and infrared spectrophotometry, magnetic susceptibility measurement and electron spin resonance spectroscopy. As a result, it is concluded that the thermal decomposition of nickel hydroxide proceeds in the following sequence:
Diffusivity of chromium salts and alums in aqueous solutions
Authors: El‐Abd Mohamed Z. , Sedahmed Gomaa H. , Zatout Ahmed A. , Negm Ahmed H. , Khalil Rida S. 
Published: July 2010

AbstractThe diffusion coefficients of potassium aluminium sulphate, ferric ammonium sulphate, chromium potassium sulphate and chromium sulphate were determined using the porous disc technique. For all salts studied linear relations were found between the diffusion coefficient and the square root of the salt concentration:

The effect of temperature on the diffusion coefficient of the salts was studied. The data were found to fit the Arrhenius equation. The activation energies for the diffusion of potash alum, ferric alum, chrome alum and chromium sulphate were found to be 1.8, 7.4, 2.8 and 3.4 kcal/mol respectively.
Gold and platinum catalysed oxidation of methanol
Authors: Hodges Colin N. , Roselaar Leonard C. 
Published: July 2010

AbstractA comparative study was made of the vapour phase oxidation of methanol in presence of gold and platinum, using a flow system at temperatures below 500°C. Over gold there is a stoichiometric conversion to formaldehyde and water. In presence of platinum, the reaction is the same up to 200°C, but at higher temperatures other oxidation products appear. Mechanisms are suggested involving interaction between chemisorbed oxygen and methanol fragments.
Fibreboard from exotic raw materials. I. Hardboard from rice straw pulps
Authors: Mobarak Fardous , Nada Abd‐Alla M. , Fahmy Yehia 
Published: July 2010

AbstractThe suitability of rice straw for hardboard making was studied. Both the mechanical and semichemical pulping methods were investigated. It was found that addition of a relatively high amount of resin (2–3 %) is essential if hardboard—comparable to average commercial samples made from wood—is to be made from mechanically prepared rice straw pulp. Mild chemical treatment of the mechanical straw pulp by sodium hydroxide at optimum conditions, however, enabled the amount of resin added to be reduced and improved the bending strength and water resistance of the board considerably. Treatment with calcium hydroxide or sulphuric acid was, generally, less successful. This was accounted for by changes in pulp chemical composition. On the other hand, when the straw was first subjected to mild chemical pretreatment followed by the mechanical defibration, many fines were formed and the resulting semichemical pulp was not suitable for hardboard.
Fibreboard from exotic raw materials. Ii. Hardboard from undebarked cotton stalks
Authors: Mobarak Fardous , Nada Abd‐Alla M. 
Published: July 2010

AbstractIt was possible to obtain hardboard of acceptable properties by mechanical pulping of undebarked cotton stalks previously soaked in water at room temperature. Pretreatment of the undebarked cotton stalks with 10–15% NaOH or Ca(OH)2 at atmospheric pressure for 4 h at 100°C, before mechanical defibration, results in considerable improvement in properties of the hardboard and less added resin requirement. The improvement due to chemical pretreatment is attributed to fibre softening. The semichemical pulps prepared from undebarked cotton stalks had remarkably high freeness compared with rice straw. Bending strength and water resistance are better than those obtained from rice straw and average samples of wood wastes.
The complete dissolution of goethite
Authors: Cornell Rochelle M. , Posner Ala N. M. , Quirk James P. 
Published: July 2010

AbstractThe dissolution of all except one sample of goethite obeyed the cube root kinetic law which implies a uniform rate of disappearance of the crystals. However, the electron microscope showed that this was only true in some cases and that there could be some compensation between size distribution in the sample and the increase in surface area through hole formation in the crystal.
Oxygen transfer coefficients by the dynamic method
Authors: Dunn Irving J. , Einsele Arthur 
Published: July 2010

AbstractModels useful in the dynamic method for KLa measurements are developed and compared. Particular attention is given to the gas phase dynamics and the oxygen electrode response time. Comparisons and error calculations are based on computer simulations. Correction factors are presented for a range of dimensionless parameters. In general, the errors resulting from neglecting the gas phase dynamics and the electrode response can be expected to be large.
Surface studies on catalysts used for deuterium exchange between hydrogen and water vapour
Authors: El‐Nour Farid H. Abou , El‐Khalik Mohamed Abd , Hassan Salah A. 
Published: July 2010

AbstractPlatinum/charcoal and nickel/chromium oxide catalysts for the isotopic exchange of deuterium between hydrogen and water vapour were prepared under optimum experimental conditions. The catalytic activity determination of both indicated higher activity for Pt/charcoal than for Ni/Cr2O3. BET measurements of the specific surface area and pore structure showed higher values for Pt/charcoal than for Ni/chromia. Chemisorption data of both catalysts allowed the determination of the specific metallic surface area, the degree of dispersion and the average particle size of the supported metals. A comparison between the results of the catalytic activity, BET measurements and chemisorption was made and indicated close agreement.
Effect of aluminium sulphate on the retention of inorganic fillers
Authors: Jaycock Michael J. , Pearson Joseph L. 
Published: July 2010

AbstractThe effect of aluminium sulphate on the retention of inorganic fillers during the process of papermaking has been investigated. It is found that increased filler retention is achieved mainly in the pH range 4–9, this increase being attributed to the fact that adsorption of charged aluminium species occurs in this pH range giving rise to a decrease in mobility, and hence ζ potential, of the fibres and a reversal of ζ potential of the filler particles. The filter is then retained by heteroflocculation of the fibres with the filler particles.
Hardened slag–cement pastes of various porosities. II. Water and nitrogen adsorption
Authors: Mikhail Raouf Sh. , Abo‐El‐Enein Salah A. , Abd‐El‐Khalik Mohamed 
Published: July 2010

AbstractSpecific surface areas and pore structure studies were carried out on hardened slag‐cement pastes. Water and nitrogen adsorption isotherms were measured, and the derived parameters were critically compared. Nitrogen areas and total pore volumes were found to be much smaller than water values. For water vapour adsorption, the specific surface areas derived from the adsorption branches are found to be lower than those derived from the resorption isotherms. Some evidence is presented in this paper that the surface area values derived along the adsorption branches are underestimated values, and that the resorption values might be considered to be nearer to the actual areas of the various pastes. Calculations of the hydraulic radii refute the hypothesis that the areas inaccessible to nitrogen are interlayer areas.
Studies on electrosynthesis of organic compounds. I. Electrolytic esterification in aqueous solutions
Authors: Osman Abdel M. , Khodair Ahmed , El‐Cheikh Fathallah , Swelim Ahmed , Aly Ibrahim 
Published: July 2010

AbstractThe anodic oxidation of methyl alcohol in the presence of different carboxylic acids was found to give the methyl ester of these acids as the main product. Neither Kolbe products nor formaldehyde were formed. These results are interpreted in terms of a free radical mechanism which involves attack of the carboxylic acids by methoxyl radicals to give the ester.
Drop size and rates of flow of water and molten ammonium nitrate through steel nozzles
Authors: Bradley John K. 
Published: July 2010

AbstractRates of flow of water have been determined through 0.079 cm bore, 1.27 cm length stainless steel nozzles under wetting and non‐wetting conditions. For a given liquid head, the rates of flow are reduced when the nozzles are non‐wetting, for example, when treated with silicones. Increasing head increases flow rate, but decreases mean particle size of the droplets formed and widens the spread in the size distribution curve. Comparative measurements for water and molten ammonium nitrate show the former to be acceptable for the study of ammonium nitrate.
Preparation and application of some new disperse anthraquinone dyes
Authors: Metwally Saoud A. M. 
Published: July 2010

Abstract(Hydroxymethyl)anthraquinones behave as primary alcohols and were used as alkylating agents for different aromatic compounds in the presence of Friedel‐Crafts catalysts. The mechanism of the reaction was studied and the position of coupling was elucidated using the mass spectrometric technique. The resulting products are free from water‐solubilising groups and were found to be valuable for dyeing synthetic fibres with different degrees of fastness properties.
A versatile and inexpensive apparatus for slab electrophoresis
Authors: Barald Pamela F. , Polanshek Mark M. , Jeter Jr James R. , 
Published: July 2010

AbstractAn apparatus for vertical slab gel electrophoresis of proteins is described. Up to four slabs of variable thickness may be used in a single run for the analysis of as many as 80 samples if the apparatus is used for one‐dimensional electrophoresis; alternatively, the slabs may be used for a second‐dimension separation of proteins previously discriminated in tubular gels or slab gel strips. The apparatus is simple in design, easy to use, and inexpensive to construct.
A problem with hydrated lime
Authors: Ridge Mayhew J. , King George A. 
Published: July 2010

AbstractA problem has occurred with hydrated lime accelerating the hardening of gypsum plaster retarded to an initial set of about 5 h. Acceleration was so severe that application by trowel was very difficult or even impossible. A sample of such lime and two samples of purified calcium hydroxide have been studied by techniques developed in this laboratory. The order of adding the lime and calcium sulphate hemihydrate to water affects the rate of hydration of the hemihydrate. Calcium hydroxide has a specific accelerating effect. The excessive acceleration produced by the lime was due to the presence of soluble salts, mainly sodium and potassium sulphates. However, a detailed study of the effects of the hydrated lime on the kinetics of hydration also revealed the actions of a nucleating agent and other impurities with inhibiting effects.
The oxidation and self‐heating of metal sulphides as an electrochemical corrosion phenomenon
Authors: Tributsch Helmut , Gerischer Heinz 
Published: July 2010

AbstractExperiments with a representative number of technically interesting metal sulphides trace out hydrogen peroxide as the reactive intermediate of sulphide oxidation. It is formed through an electrochemical reduction of molecular oxygen. The formation of sulphur or sulphate as the final state of oxidation is determined by consecutive reactions which are critically dependent on the catalytical properties of the surface and the solution for hydrogen peroxide decomposition. The individual steps of the reaction are discussed in some detail. Conclusions with respect to a possible control of the autogeneous heating are drawn.
Studies on cyanine dyes. IV. Synthesis of new styryl oxa‐cyanine dyes
Authors: Osman Abdel‐Megied , Youssef Mohamed Salah K. , Khalil Zarfi H. 
Published: July 2010

AbstractThe condensation reaction of benzoxazole‐2‐carboxaldehyde (I) with quaternary salts of heterocyclic compounds, in the presence of piperidine as a catalyst, afforded styryl cyanines (II). Interaction of (I) with the non‐quaternised heterocyclic compounds at a longer time gave the corresponding dimethine bases (III). On the other hand, benzoxazole‐2‐carboxaldehyde‐3‐ethiodide (IV) interacted with quaternised and non‐quaternised heterocyclic compounds achieved styryl cyanines of the type (V) and (VI), respectively. Absorption spectra for these compounds in EtOH are discussed.
Studies on cyanine dyes II. Preparation of ferrocene cyanines
Authors: Osman Abdel Megied , Hassan Khairy M. , Khali Zarif H. , Turin Vlademir D. 
Published: July 2010

AbstractThe condensation of ferrocene aldehyde with quaternary salts of 2‐methyl heterocyclic compounds, in the presence of piperidine as a catalyst, afforded ferrocenyl cyanines. Interaction of ferrocene aldehyde with the non‐quaternised heterocyclic compounds, in the presence of pyridine and sodium ethoxide as a condensing agent, afforded styryl ferrocenes.
Energetics of fungal growth: The effect of growth‐limiting substrate on respiration of Penicillium chrysogenum
Authors: Mason Hugh R. S. , Righelato Renton C. 
Published: July 2010

AbstractIn sucrose‐limited culture of Penicillium chrysogenum the growth yields, corrected for maintenance, for sucrose and oxygen, at dilution rates below 0.05 h−1, were 86 g dry biomass/mol hexose and 39 g dry biomass/mol O2. Similar yields have been observed with other moulds and with yeasts. In oxygen‐limited culture the yield from oxygen was two to three times higher and the yield from sucrose about 10% higher than in sucrose‐limited culture. In phosphate‐limited cultures the respiration rate was unaffected by oxygen concentrations between 0.06 and 0.18 bar and by the concentration of sucrose in the medium between 0.1 M and 0.3 M. The excess of sucrose over the growth requirement was metabolised to organic acids, predominantly malate and gluconate. The results suggest that, in the presence of excess oxygen, the respiration rate is controlled by the biosynthetic demand for energy.
Scaling‐up of process for production of antibiotic of myxococcus xanthus TA
Authors: Mizrahi Avshalom , Arnan Joseph , Miller George , Liron Zvi , Manai Moshe , Batus Yedidya , Rosenberg Eugene 
Published: July 2010

AbstractA process for the production of Myxococcus xanthus TA (M. xanthus TA) antibiotic was scaled‐up to bench and pilot plant scales. The process includes the following steps: (a) propagation of M. xanthus TA in cultures of up to 750 litres. After 4 days of growth the maximum antibiotic yield achieved was 24 units/ml supernatant, and the highest titres were obtained at a low oxygen absorption rate of 0.2; (b) processing of the clarified culture supernatant. Two methods were successfully piloted: the chloroform extraction method and the kaolin adsorption method. Both methods were followed by elution with 20% methanol in chloroform. The recoveries of antibiotic activity were 90% and 85% respectively by the two methods. The process described could be used for the large‐scale preparation of the novel antibiotic of M. xanthus TA.
Isolation of fatty acids from an egyptian petroleum
Authors: Khodair Ahmed I. , Abdel‐Wahab Aboel‐Magd A. 
Published: July 2010

AbstractA mixture of straight‐chain fatty acids (from C7 to C19) was isolated from an Egyptian petroleum via extractive crystallisation with urea. Although the total acidic content in Egyptian petroleum is low, the fatty acids constitute at least 32% of the total acids. n‐Pentadecanoic and n‐nonadecanoic acids were isolated for the first time from petroleum acids by a sequence involving fractional distillation of the methyl esters, extractive crystallisation with urea and recrystallisation of amide derivatives.
Synthesis and study of dyeing properties of some new silicon‐containing anthraquinone dyes
Authors: Metwally Saoud A. M. 
Published: July 2010

AbstractSilicon‐containing dyes based on the 2‐methylanthraquinone chromophore have been prepared by interaction of γ‐aminopropyltriethoxysilane with 2‐(substituted methyl) anthraquinones. These dyes are amorphous glass‐like solids and their possible applications, particularly to glass fibres, have been examined.
Thermal decomposition of uranium peroxide hydrates
Authors: Sato Taichi 
Published: July 2010

AbstractThe thermal decomposition of uranium peroxide hydrates, UO4·4H2O and UO4·2H2O, has been investigated by thermal analyses, X‐ray diffraction study and infrared spectroscopy. As a result, it is concluded that the thermal decomposition of uranium peroxide hydrates proceeds in the following sequence:
Analysis of immobilised multi‐enzyme reaction systems with michaelis‐menten kinetics
Authors: Ramachandran P. A. , Krishna R. , Panchal C. B. 
Published: July 2010

AbstractThe consecutive sequence of reactions S → P1 → P2 taking place inside a permeable spherical particle is analysed for the case in which the enzyme‐catalysed steps in the reaction follow Michaelis‐Menten type kinetics. The case in which each step in the reaction is inhibited by its product is also considered. The theoretical analysis takes into account both interparticle and intraparticle diffusional limitations and utilises an orthogonal collocation technique to obtain the effectiveness factor and selectivity of the reaction sequence. The orthogonal collocation method is found to be both convenient and simple and the analysis should prove useful in the design of immobilised multi‐enzyme reactors.
Some cultural conditions for the production of puromycin by Streptomyces alboniger
Authors: Shaheen Ahmed B. , Abou‐Zeid Abou‐Zeid A. , El‐Diwany Ahmed I. 
Published: July 2010

AbstractA simple synthetic medium was used in the fermentative production of puromycin to investigate the efficiencies of certain ingredients in stimulating the organism for higher yield. Addition of certain amino acids, especially L‐histidine, L‐glutamic acid, L‐proline, L‐aspartic acid, DL‐methionine, L‐leucine, β‐alanine, L‐isoleucine, DL‐alanine, L‐tyrosine and L‐glycine, increased the antibiotic yield compared with the control. Lactic acid was more suitable for antibiotic production than the other organic acids used, i.e. maleic, acetic, malic, tartaric and fumaric acids. Addition of certain vitamins, namely cobalamin (vitamin B12), nicotinic acid, vitamin B1 and folic acid, did not markedly increase the antibiotic yield. Certain trace elements, such as zinc, copper, iron, manganese and cobalt, played an important role in the biosynthesis of puromycin by Streptomyces alboniger NRRL B‐2403. The optimum concentrations of these trace elements were 0.2000, 0.0020, 0.0005, 0.3000, and 0.0050 g/litre respectively. The optimum concentration of K2HPO4 favouring bio‐synthesis of puromycin was 1.5 g/litre. The amino acids formed in the microbial cells of Streptomyces alboniger NRRL B‐2403 during the production of puromycin in the synthetic medium were determined quantitatively. Generally, all the amino acids recorded appeared in the microbial cells.
Study of some sulphur‐group solvents for aromatics extraction by gas chromatography
Authors: Rawat Bachan S. , Gulati Indar B. , Mallik Kanai Lal 
Published: July 2010

AbstractNineteen organosulphur solvents have been studied by gas chromatography as potential solvents for the extraction of aromatics. The activity coefficients of nine typical hydrocarbon solutes have been determined in these solvents at three temperatures. From the activity coefficient data, the selectivities of all the solvents have been calculated for benzene with respect to each of the other hydrocarbons in order to screen them for extraction studies. Solvent losses in the g.c. column were also studied.
Copper complexes of some tetra‐ and pentapeptides containing polyfunctional amino acids
Authors: El‐Naggar Ahmed M. , Zaher Mahmoud R. , El‐Salam Abd‐Elmonem Abd 
Published: July 2010

AbstractCopper complexes of some tetra‐ and pentapeptides [(I)‐(VI)] containing lysine and ornithine are spectrophotometrically examined. It is shown that all tetra‐ and pentapeptides form red or reddish violet copper complexes with λmax 515–540 nm, and copper‐peptide ratio 1:1. The results achieved confirmed that the N6‐amino group of the lysine residues or the N5‐amino group of the ornithine residues do not participate in complex formation of tetra‐ and pentapeptides even when lysine or ornithine form the N‐terminal amino acid in the peptide.
Hydrodynamic behaviour and oxygen transfer rate in a pilot plant fermenter. I. Influence of viscosity
Authors: Páca Jan , Ettler Petr , Grégr Vratislav 
Published: July 2010

AbstractThe effects of varying impeller speed, aeration rate and viscosity on mixing time, power consumption and oxygen transfer rate were studied in the pilot plant fermenter. The rheological behaviour of erythromycin fermentation broth was simulated by colloidal starch solutions at apparent viscosities of 0.02–0.20 Pa/s. The volumetric oxygen transfer rate coefficient was determined by the sulphite and static method. The experimental results showed that at low viscosities, up to of 0.02 Pa/s, the suitable range of impeller speed is 250–300 min−1 at aeration rate 0.6–0.8 VVM from the point of view of power input (2.6–2.8 kW/m3) and sufficient coefficient KLa (160–200 h−1). At viscosities higher than 0.02 Pa/s (with pseudoplastical character) the suitable range of impeller speed is 300–350 min−1 at the same aeration rate. Then the power input for mixing is 3.0–3.5 kW/m3 and the coefficient KLa ∼ 50 h−1.