bluuebunny/crossref_metadata_2025 huggingface dataset:
A routine method for measuring the efficiency of ferric oxide as an extractor of hydrogen sulphide from air
Authors: Sebborn Walter S.
Published: July 2010

Measurement of the absorptive efficiency of ferric oxide is made by passing a measured volume of air containing a known low concentration of H2S through the sample at a known constant velocity, and measuring the residual H2S which has not been extracted. This last measurement is carried out by passing the air through a paper impregnated with silver nitrate, and measuring the optical transmission density of the stain formed. Concentrations are calculated from the sulphide stain densities and the volumes of air passed through the papers. The calibration technique forms the basis of a method of measurement of trace amounts of H2S in the atmosphere, and is unaffected by the presence of SO2.
The bromate oxidation of thioglycollic acid
Authors: Mapstone George E.
Published: July 2010

The oxidation of thioglycollic acid (TGA) by bromate is an autocatalytic reaction which is further catalysed by the presence of soluble ferric iron. The reaction rate decreases at increasing pH but, in the presence of ferric iron, there is an optimum pH of about 9.0. When the pH is below 7.0 the reaction rate is again increased due to the liberation of free bromine.
Cation exchange removal of copper from aqueous ammonia solutions
Authors: Bull Patrick S. , Evans John V.
Published: July 2010

Stability constants for copper—ammine species absorbed on sulphonated polystyrene cation‐exchange resin have been estimated by the method of Bjerrum. The following values are obtained; log k1 = 4.5, log k2 = 3.7, log k3 = 3.1, log k4 = 2.5, log k5 = 1.9. There is evidence that in the resin environment the fifth coordination position on copper(ii) is equivalent to the first four, contrary to the situation in aqueous solution. Ion‐exchange column experiments show that ammonia dosing of steam power plant feed‐water will not affect the ability of ion‐exchange condensate polishing plant to remove copper from the feed‐water.
Hardened slag‐cement pastes of various porosities I. Compressive strength, degree of hydration and total porosity
Authors: Mikhail R. Sh. , Abo‐El‐Enein S. A. , Gabr N. A.
Published: July 2010

Hardened blast‐furnace slag‐cement pastes were prepared from cements of different Blaine areas, and mixed with various water/cement ratios in the range 0.20–0.70. The pastes were cured for various periods ranging from 1 to 365 days, and the degree of hydration, total porosities, and compressive strengths were determined. It is recommended in this investigation that the compressive strength values be compared at either constant total porosities or constant degree of hydration. The results obtained could indicate that the total porosity plays a more dominant role in affecting the strength than the degree of hydration.
Copper complexes of Di‐, Tri‐ and hexapeptides containing N2, N4‐diaminobutyric acid
Authors: Salem E. M. S. , El‐Naggar A. M. , Zewail M. A.
Published: July 2010

Sixteen copper complexes of di‐, tri‐ and hexapeptides containing N2, N4‐diaminobutyric acid are studied spectrophotometrically. The λmax, and colour of the complex is independent of the sequence of the amino acid in any of these peptides.

The N4‐amino group of the A2bu‐residues do not participate in complex formation. However, the hydrazide group of di‐ and tripeptide hydrazides participates in complex formation.
1,2‐Asymmetric induction when grignard reagents are added to of‐aminoketones. I. The influence of different factors and mechanisms of induction
Authors: Gaset Antoine , Maurette Marie‐Thérèse , Lattes Armand
Published: July 2010

The problem of 1,2‐asymmetric induction has been studied as Grignard reagents were added to α‐aminoketones. The experimental factors have been modified in terms of the hypothesis of an interaction between the amino function and the Grignard reagents. The variations resulting from these changes have enabled an interpretation to be put forth of the phenomena depending on the equilibrium between a dipolar and a cyclic model.
1,2–Asymmetric induction when grignard reagents are added to α‐aminoketones. III. A highly selective preparation of R*S* α‐aminoalcohols
Authors: Audoye Paul , Gaset Antoine , Lattes Armand
Published: July 2010

In order to prepare selectively α‐aminoalcohol R*S* diastereoisomers by adding Grignard reagents to the corresponding α‐aminoketones, the influence of the following factors has been studied successively: permutation of substituents: reagents–substrates, complexing nature of the solvent, addition of magnesium salts, and nature of the halogen. In this way a list has been drawn up of experimental conditions leading to selective or specific preparation of aminoalcohols.
Production of acidified active carbon by wet oxidation and its carbon structure
Authors: Matsumura Yoshimi
Published: July 2010

Active carbon was oxidised in several oxidising solutions and measured for its surface acidity, specific surface area, X‐ray diffraction patterns, ESR spectra and gas adsorption isotherms. The favourable oxidising conditions for acidifying active carbon were speculated. Three kinds of steam activated coconut‐shell carbon were treated by solutions of nitric acid, alkaline permanganate, acidic permanganate with nitrate, acidic dichromate and of chlorate in fuming nitric acid. Graphite was similarly treated as a control. When the carbon was oxidised by all the above mentioned reagents except the acidic dichromate, its surface acidity increased unavoidably accompanied by the surface area reduction in almost a linear relation. However, the surface area reduction was extensive in the carbons oxidised by acidic dichromate. Neither the crystalline nor the amorphous carbon fraction was selectively oxidised by any of the oxidants to a significant extent when observed by X‐ray diffraction, probably because of the lower levels of crystallisation in the micelles. On the other hand, the change of free radicals was observed by most of the oxidations which indicated the conformational change of the carbon at molecular level. The improved adsorption of ammonia was observed on the oxidised carbon up to 20 times and that of sulphur dioxide and water vapour to a few times. The adsorption of n‐hexane was negatively affected by the oxidations.
Strength of autoclaved portland blast furnace cement
Authors: Kamel Abdel‐Aziz H.
Published: July 2010

The optimum autoclaving conditions for Portland blast furnace cement of 35% slag content, in the absence as well as in the presence of fine quartz, have been investigated. It was found that maximum strengths were developed in an autoclaving period of 4 h at 230 lb/in2; the strength values obtained for vibrated mortar cubes were 470 kg/cm2 for 1 : 3 (W) cement–standard sand mix, and 904 kg/cm2 for 1 : 0.5 : 2.5 cement–fine sand–standard sand mix. Strength values for various autoclaving pressures and times are given.
Development of a technique for measuring the degree of dispersion of chrysotile fibre in aqueous systems
Authors: Jaffé Daniel , Kuntze Richard A.
Published: July 2010

Chrysotile asbestos, when dispersed in an aqueous solution of a soap or a detergent by high shear mixing, results ultimately in a colloidal dispersion consisting of fibrils of approximately 30 nm in diameter and very high aspect ratio. In the intermediate stages of the dispersion process, slurries are produced which are represented by a wide range of colloidal concentrations and conversely a wide range of undispersed, macroscopic fibre concentrations. The degree of dispersion in these slurries and the dispersion mechanism cannot be assessed by existing methods of analysis. A new method capable of estimating the degree of fibre dispersion has been developed and has been termed Load Impulse Analysis. In the dispersion process, the disappearance of macroscopic fibres may be estimated and the development and destruction of a colloidal structure has been illustrated through this type of analysis. The meaning of the viscosity of a fibre dispersion measured at a low shear rate is also made clearer.
Comments on the thermodynamics of urea synthesis
Authors: Barański Andrzej , Fuliński Andrzej
Published: July 2010

The thermodynamics of urea synthesis from ammonia and carbon dioxide is discussed. It is pointed out that Van't Hoff's rule cannot be applied to this process because of the pressure dependence of the equilibrium constant.
Reaction of hydroxymethylanthraquinones with thionyl chloride
Authors: Metwally Saoud A. M.
Published: July 2010

The reaction of thionyl chloride with some hydroxymethylanthraquinone derivatives was investigated. The reaction product was found to be dependent on other ring substituents and on the reaction temperature. In the case of amino derivatives and at lower temperatures, chlorosulphinylmethylanthraquinones were obtained; while at higher temperatures, chlorination of the anthraquinone nucleus occurred. Hydroxy derivatives gave only chloromethyl compounds.
Isomerisation of xylenes over a silica–alumina catalyst
Authors: Bhattacharya Rabindra Nath , Rao Hejamadi Shreepathi
Published: July 2010

The catalytic vapour phase isomerisation of m‐xylene into o‐ and p‐xylenes was studied in a flow system in the temperature range 460–700 °C, and over a wide range of space velocities on a silica–alumina catalyst. The isomeric distribution of the products, as determined by a combination of spectroscopic and chromatographic methods, was found to be consistent with calculated equilibrium values. Reduced pressures tended to suppress undesirable side reactions such as disproportionation and favoured the isomerisation. First order kinetics appeared to be applicable and the overall activation energy for both isomerisation reactions (i.e. meta‐ to para‐, and meta‐ to ortho‐) was found to be close to 25 kcal/mol, being of the same order of magnitude in both cases. Isomerisation of o‐, m‐ and p‐xylenes failed to occur even at 600 °C under non‐catalytic thermal treatment, although formation of polynuclear ring systems (“coke”) in small quantities was observed. The results appear to indicate that the mechanism of isomerisation of xylenes over acidic catalysts involves essentially ionic intermediates. Based on the evidence obtained, it is concluded that the vapour phase isomerisation of xylenes apparently proceeds via the formation of a localised π‐complex, leading to a 1,2‐intramolecular shift of the methyl group.
Mechanism of photocontact dermatitis due to an anthraquinone disperse dye
Authors: Davies A. Keith , Hamblett Ian , McKellar John F. , Phillips Glyn O.
Published: July 2010

The photochemistry of an anthraquinone‐based disperse dye that gives rise to photocontact dermatitis in workers engaged in its manufacture has been investigated. The main photochemical reaction of the dye is that of efficient production of singlet oxygen which sensitises the oxidation of both tryptophan and lecithin. It is suggested that a similar mechanism is responsible for the photodermatitic activity in human skin and the significance of this mechanism is discussed in relation to lysosome membrane damage.
Effect of copper and oxygen on the yields of individual nitroalkanes in the vapour phase nitration of paraffin hydrocarbons
Authors: Mladenov Ivan , Toromanova‐Petrova Pepa
Published: July 2010

The effect of copper, oxygen and their combined effect on the yields of individual nitroparaffins in the vapour phase nitration of gas propane–butane with nitric acid is studied. It is found that the presence of copper or copper and oxygen in the reactor does not change the total yield of nitrocompounds, while in the presence of oxygen higher yields are obtained. All the additives investigated move the proportion of single nitroparaffins in the product mixture towards higher molecular species, while in the case of nitration without additives this proportion moves in the direction of the nitromethane. With regard to the primary and secondary nitroalkanes, copper does not change their yields, but oxygen increases the yield of secondary ones.
Standard vapour mixtures by means of a multi‐capillary flow‐proportioner
Authors: Szeri Levente S.
Published: July 2010

A dynamic method is described for the preparation of standard gaseous mixtures of condensable vapours such as water vapour, gas odorants or hydrocarbons with an accuracy of better than ·5%. The possible concentration range is from a few parts per miliion to saturation level. The method is also suitable for the preparation of multi‐vapour mixtures.
A comparison of surface tension data for aqueous dodecylammonium salt solutions
Authors: Finch James A. , Smith Gordon W.
Published: July 2010

Literature data for natural solutions is compared and a wide spread of surface tension values is shown. A comparison of three techniques, capillary rise, drop weight and maximum bubble pressure failed to indicate that the technique alone was responsible. Repeating the determinations at pH 9.5 did indicate marked dependence on the technique employed. Wetting problems coupled with a pronounced time dependence of the surface tension were responsible. The bubble pressure method is shown to be the most suitable, being versatile enough to handle the dynamics. A comparison of critical micelle concentration (c.m.c.) data as a function of pH with the calculated solubility limit of dodecylamine as a function of pH revealed an interesting incompatibility; at pH greater than 9, the indicated c.m.c. was greater than the solubility limit.
Kinetics of utilisation of a highly polymerised carbon source (starch) in a chemostat culture of klebsiella aerogenes: Pullulanase and α‐amylase activities
Authors: Hernandez Eovaldo , Pirt S. John
Published: July 2010

Starch and amylose utilisation by K. aerogenes under chemostat conditions were studied as models of polymer degradation in the chemostat. The effects of growth rate on the process and upon cellular concentrations of α‐amylase and pullulanase were determined. The debranching enzyme (pullulanase) activity was greatest when the highly branched polymer (starch) limited growth. The pullulanase activity varied inversely with the dilution rate when starch limited growth but increased with dilution rate when nitrogen limited growth. Pullulanase seems to be the enzyme controlling growth rate. The polymer substrate affinities (Ks values) expressed on a molar basis were about the same as the values observed for monomers.
Simulation of growth of methane‐utilising bacteria in batch culture
Authors: Shoda Makoto , Nagai Shiro , Aiba Shuichi
Published: July 2010

A kinetic model for batch growth of a methane‐utilising bacterium is presented, using data from previous experimental work on the specific rates of growth, respiration and methane consumption of the bacterium. A two‐substrate model with respect to methane and oxygen was employed to represent the specific rate of methane consumption. Employing the various coefficients assessed previously, the bacterial growth was simulated in relation to changing partial pressures and mass‐transfer coefficients for both gases. The simulated results are discussed in light of the experimental data published by other workers on both pure and mixed populations of methane‐utilising bacteria. The optimal partial pressures of oxygen and methane derived from the model were found to play a decisive role in connection with inflammability.
Solubility and distribution data for benzene and toluene between aqueous and organic phases
Authors: Hanson Carl , Ismail Hamed A. M.
Published: July 2010

Solubilities of benzene and toluene in mixtures of nitric and sulphuric acids of various compositions have been measured and also distribution coefficients. Correlations are presented to allow distribution coefficients to be predicted in acid mixtures of compositions typically used for aromatic nitration in industry.
Correct estimation of thermal transpiration effect for krypton
Authors: House William A. , Jaycock Michael J.
Published: July 2010

The thermal transpiration effect for krypton is investigated using a number of models previously suggested. Past workers have found that for small diameter tubes, the low pressure region may not be satisfactorily represented by the semi‐empirical Liang equation. The data obtained in this work show that using αHe = 160.3 (N–2 m2) and βHe = 59.1 (1 — Rm)(N–1 m), the Liang equation fits the whole pressure range with a value of the constant, Φg = 3.7. In this equation Rm = (T1/T2)1/2 and the values of the constants are applicable when T1 = 77.7 K and T2 = 293.3 K. It is discussed how the temperature dependence of the constants may be allowed for.
Kinetics of leaching of asbestos minerals at body temperature
Authors: Chowdhury Sudarshan
Published: July 2010

Leaching of three commercially used asbestos (chrysotile, crocidolite and amosite) was carried out in water at 37 °C under both static and dynamic conditions. True equilibrium was not established in the maximum time allowed (2 months). After a certain time which varied from sample to sample, metal ions were released at a steady rate. The high pH recorded in the case of leaching of chrysotile and crocidolite (10 and 9 respectively) suggested the presence of some mineral impurities, later identified as brucite in chrysotile and ankerite in crocidolite. Since most chrysotiles are contaminated with some magnesium impurities which are impossible to remove without changing the chemical nature of chrysotile itself, it is virtually impossible to study the actual leaching kinetics of pure stoichiometric and natural chrysotile.
Assessment of fluidised bed ion exchange equipment
Authors: Slater Michael J.
Published: July 2010

Continuous countercurrent fluidised bed ion exchange equipment has certain advantages over moving packed bed or fixed bed equipment. The treatment of high flow rate dilute waste streams containing particulate matter and the processing of uranium ore unfiltered pulps are considered in the application of fluidised bed systems. Methods of obtaining design data are outlined and techniques for calculating the performance of continuous counterflow systems are proposed for various situations.
Preparation and study of some alkali metal salts of gluconic acid including lithium gluconate
Authors: Dutt Sadhan Kumar , Bhattacharyya Asit
Published: July 2010

A general method for preparation of the alkali metal salts of gluconic acid by electrolysing glucose in a 1% alkali bromide electrolytic solution containing alkali carbonate/bicarbonate is described.
Kinetics of the methane–steam reaction over nickel catalyst in a continuous stirred tank reactor
Authors: Quach Thi Quy Phung , Rouleau Denis
Published: July 2010

The kinetics of steam‐methane reforming over a supported nickel catalyst have been investigated in a continuous stirred tank reactor, under isothermal conditions between 350 and 450 °C at 1–2 atm. The rate data obtained have been analysed by the Hougen–Watson method. Linear as well as non‐linear least squares analysis combined with other statistical considerations were used to discriminate among forty reaction rate models. The following Hougen–Watson type rate equation has been proposed:

The constants in the rate equation have been expressed as functions of temperature.
Treatment of tannery effluents by surface adsorption
Authors: Wang Lawrence K. , Dahm Douglas B. , Baier Robert E. , Ziegler Robert C.
Published: July 2010

A promising technique emphasised in the proposed tannery waste treatment system is surface adsorption. Specific surface adsorption processes studied were foam separation without additives, adsorbing colloid flotation, carbon adsorption, and adsorption flotation. Results show that foam separation without additives is not a feasible process for the removal of either dissolved organics or suspended solids from tannery wastes. Adsorbing colloid flotation is feasible for the primary treatment of tannery wastes, provided that dimethyldihydro‐genated‐tallow ammonium chloride or the like is used as a collector. Secondary treatment of tannery effluent by carbon adsorption alone is not sufficient. However, by combining carbon adsorption and flotation into a single process (adsorption flotation) a high fractional removal of both dissolved and suspended pollutants can be achieved.
Adsorption of dissolved organics from industrial effluents on to activated carbon
Authors: Wang Lawrence K. , Leonard Richard P. , Goupil Dennis W. , Wang Mu Hao
Published: July 2010

Industrial effluents usually include multicomponent organic solutes. The optimum pH for adsorption of a specific industrial effluent on activated carbon should be determined experimentally because, in general, more than one mechanism is involved. A series of experiments was conducted to establish the influence of the initial hydrogen ion concentration on carbon adsorption of organic solutes. For these studies, powdered activated carbon was used, and the water systems studied included both single component pure organic compounds as well as multicomponent organic wastes. Results indicate that the pH effect upon the effectiveness of carbon adsorption mainly depends upon the nature of the adsorbed substance. In general, the degree of ionisation is the controlling factor for adsorption of ionic organic solutes on activated carbon. Adsorption reaches a maximum at the point of least ionisation of the adsorbate. As the organic compounds become more complex (i.e. longer hydrocarbon chains, higher molecular weights, increased branching), the electrical adsorption forces between activated carbon and ionic organic solutes will govern. Anionic surfactants meet with decreased electronegative repulsive forces at low pH levels, which increase the effectiveness of carbon adsorption. However, the adsorption of a cationic surfactant is increased by an increase in the electronegative carbon surface at high pH levels. When ionic organic solutes become much more complex, like a polymer, the effects of both ionisation and electrical adsorption forces become less important. Instead, the adsorption rate will be controlled by the extent of hydrolysis caused by the pH adjustment. For non‐ionic organic solutes, chemical reaction(s) between the adsorbate and the added chemical (acid or base) for pH adjustment is an important controlling factor. Again, hydrolysis is responsible for the breakdown of larger size molecules to smaller sizes. Then an increase in adsorption rate with decreasing molecular weight of adsorbate is expected.
Analysis of alloys and salt solutions by β‐ray backscattering
Authors: Bahadur Aruna , Maji Krishna Das , Kumar Rajendra
Published: July 2010

This investigation reports the results of a study undertaken to assess the suitability of using the GM counter for measuring the intensity of β‐backscattered radiation to determine the chemical composition of binary solid alloys, and aqueous salt solutions containing a metallic radical. The results indicate that the technique is not suitable for the determination of the composition of binary alloys since the error is in the range of 1.2–2.3 wt‐% metal. The technique can be conveniently adapted for aqueous salt solutions where the maximum error is approximately 0.2 wt‐% metal for metallic elements with atomic number greater than 20.
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

The 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

Natural 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

The 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

The 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

A 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

The 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

It 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

The 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

Models 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

Platinum/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

The 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

Specific 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

The 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

Rates 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

(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

An 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

A 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

Experiments 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

The 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

The 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.
Model studies on mixtures of particles
Authors: Scully D. B.
Published: July 2010

The proportional standard deviation for a number of binary mixtures has been calculated. The mixtures are taken to have a basic cubic structure, each cube containing particles of one kind only. As the cubes contain progressively increasing numbers of particles, the mixture becomes less well mixed and the proportional standard deviation increases to a limiting value.
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

In 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

A 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

A 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

Silicon‐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

The 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

The 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

A 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

Nineteen 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

Copper 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

The 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.
Influence of some compounds on gentamicin formation by Micromonospora purpurea
Authors: Abou‐Zeid Abou‐Zeid A. , Eissa Abd El‐Wahab I. , Salem Hassan M.
Published: July 2010

Production of gentamicin antibiotics by Micromonospora purpurea was carried out successfully on a synthetic medium which contained the following ingredients (g/litre): glucose 10.0, NaNO3 2.0, KH2PO4 1.0, and CaCO3 1.0. The initial pH value of the fermentation medium was adjusted to 7.2. Effects of certain amino acids, organic acids, vitamins, purine and pyrimidine bases on the fermentative production of gentamicins were revealed. The ingredients which increased the antibiotic yields were phenylalanine, isoleucine, lysine, methionine, leucine, arginine, glycine, β‐alanine, cystine, tryptophan, malic acid, maleic acid, cobalamin, folic acid, riboflavin, vitamin B1, vitamin B6, biotin, nicotinamide, uracil, adenine, guanine and adenosine. Trace elements (Co, Mo, Fe, Cu, Zn and Mn) exhibited their important role on the biosynthesis and formation of gentamicins by Micromonospora purpurea.