bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some observations on calcium silicate brick specimens in the autoclave
Authors: Walker Richard C. , Purton Michael John 
Published: July 2010

AbstractAn autoclave with an externally generated steam supply and fitted with windows has been used to observe calcium silicate brick specimens with varying initial moisture contents during the autoclaving cycle. In particular, gains and losses in weight due to condensation and evaporation of water were recorded.Tests on the autoclaved specimens indicated that bulk density, compressive and transverse strength varied with initial water contents of the mix within the range 4 to 14%. Specimens with high water contents expanded and cracked during autoclaving. C2SH(A) rather than CSH(II) was formed in mixes with low water contents at short autoclaving times.
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

AbstractMeasurement 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

AbstractThe 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

AbstractStability 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

AbstractHardened 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

AbstractSixteen 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

AbstractThe 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

AbstractIn 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

AbstractActive 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

AbstractThe 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

AbstractChrysotile 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.
Reaction of hydroxymethylanthraquinones with thionyl chloride
Authors: Metwally Saoud A. M. 
Published: July 2010

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractA 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

AbstractLiterature 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

AbstractStarch 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

AbstractA 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

AbstractSolubilities 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

AbstractThe 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

AbstractLeaching 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

AbstractContinuous 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.
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

AbstractThe 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

AbstractA 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

AbstractIndustrial 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

AbstractThis 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.