bluuebunny/crossref_metadata_2025_split huggingface dataset:
Foam separation of active carbon
Authors: Grieves R. B. , Chouinard E. F. 
Published: July 2010

AbstractAn experimental investigation is presented of the foam separation of powdered active carbon, equilibriated with an aqueous, synthetic waste water containing phenol and a cationic (ethylhexadecyldimethylammonium bromide (EHDA‐Br)), anionic (dodecyl sodium sulphate), or non‐ionic (alkyl phenoxy polyethoxy ethanol) surfactant. The effect of surfactant, of pH, of initial carbon concentration, and of initial surfactant concentration on the flotation of carbon is investigated. At pH 3, 7, and 10, the cationic surfactant yields the best flotation of carbon, which increases with increasing pH. At pH 7, a suspension containing 800 mg/1 carbon can be reduced to 24 mg/1 in 10 min. with 0·37 mM EHDA‐Br. The relative concentrations of carbon and of surfactant must be controlled carefully to yield sufficient free surfactant to obtain a foam but not excessive free surfactant to impair the foam separation process. Foam volumes are controlled by free (non‐adsorbed) surfactant.
An infra‐red frequency shift method for the determination of the high‐temperature phases of aluminosilicate minerals
Authors: Mackenzie K. J. D. 
Published: July 2010

AbstractShifts in the frequency of certain peaks in the i.r. spectrum of kaolinite during mullite formation were correlated with X‐ray analysis data for the high‐temperature phases. The method provides a means of following the high‐temperature reactions of these minerals, and is rapid, requires only small amounts of sample (mg), and is accurate even for samples of low crystallinity.
Formation and reactivity of borides, carbides and silicides. II. Production and sintering of boron carbide
Authors: Glasson D. R. , Jones J. A. 
Published: July 2010

AbstractThe principal methods of boron carbide production are compared and their thermodynamics are examined. Mechanism of carbide formation and sintering of the products are discussed and investigated further. High‐purity stoicheiometric B4C of submicron size was produced on a semi‐technical scale by reduction of diboron trioxide with carbon and magnesium. Rates of sintering were determined from changes in surface areas and average crystallite and aggreagte sizes.Sintering of boron carbide was enhanced by increased temperature and time of calcination. Addition of chromium accelerated sintering at temperatures above 1600° and especially at 1800°. For more extensive sintering, submicron powders from the magnesium reduction process were more suitable than the coarser samples given by the electro‐thermal carbon reduction; the latter required ballmilling to provide suitable grain size composition for effective hot pressing.
Note on stability of p‐nitrophenol in aqueous solutions
Authors: Rao S. R. , Ramakrishna V. 
Published: July 2010

AbstractIt has been shown that p‐nitrophenol (PNP) solution is stable only at pH ≥ 9 when PNP is in the completely ionised form. In benzene, PNP exists in a neutral molecular form. These considerations are important in the estimation of surface areas of solids by adsorption of PNP from solution.
An impact test for road binders
Authors: Briggs D. K. H. 
Published: July 2010

AbstractA study has been made of the energy absorbed in rupturing a road binder film in a pendulum impact machine. At high temperatures the energy is absorbed by viscous traction, at low temperatures by elastic strain energy, and in the intermediate visco‐elastic region the energy rises to a marked maximum providing optimum conditions for stone retention by the binder.A standard test at − 10° gives an energy value, under conditions of brittle fracture, which is demonstrated to be suitable for comparing tars of known equiviscous temperatures and which reflects the width of the visco‐elastic peak, giving a measure of resistance to brittle failure of the binder.
Crystallisation processes in aluminium hydroxide gels. IV. Factors influencing the formation of the crystalline trihydroxides
Authors: Aldcroft D. , Bye G. C. , Hughes C. A. 
Published: July 2010

AbstractThe formation of crystalline aluminium trihydroxides from aqueous suspensions of pseudoboehmite, obtained by the hydrolysis of aluminium s‐butoxide, has been examined by X‐ray diffractometry, nitrogen adsorption and dilatometry.The results obtained have been interpreted in terms of a mechanism involving dissolution of the pseudoboehmite. For those suspensions with which the recrystallisation was followed dilatometrically, first‐order kinetics were found, suggesting that random nucleation of trihydroxide crystals is involved. The rate of recrystallisation was decreased by the addition of organic solvents to the aqueous suspension and also, initially, by an increase in temperature. At the same time the proportion of gibbsite produced in admixture with bayerite was reduced and that of nordstrandite increased. It is concluded that the retardation is due, at least in part, to an increase in the crystallinity of pseudoboehmite which has been found to accompany the introduction of the organic solvents. The increased crystallinity must result in a decrease in the solubility and rate of solution of pseudoboehmite; under these conditions nordstrandite formation appears to be promoted.Neutron activation and spectroscopic analysis of hydroxide samples showed that storage of aqueous suspensions in glassware resulted in pick‐up of sodium and silica at the ppm level. The changes in these levels as recrystallisation occurred suggested that retention of the products of glass dissolution was occurring in a way which depended on the surface area of the hydroxide. No variation related to the phase composition of the trihydroxide mixtures was observed.
Formation and reactivity of nitrides. IV. Titanium and zirconium nitrides
Authors: Glasson D. R. , Jayaweera S. A. A. 
Published: July 2010

AbstractThe reactivities of the interstitial titanium and zirconium nitrides have been compared. Samples of these nitrides have been converted to oxides by being calcined in air. Changes in phase composition, surface area, crystallite and aggregate sizes have been correlated with oxidation time and temperature.Crystallites of rutile, TiO2, split off from the remaining titanium nitride before they sinter, and inhibit further oxidation. Zirconium nitride oxidation is complicated by formation of tetragonal ZrO2 at higher temperatures, particularly over 1200°, and monoclinic ZrO2 at lower temperatures. The nitride initially forms the so‐called ‘amorphous’ cubic ZrO2, notably between 400–600°, which may be stabilised somewhat by the remaining cubic ZrN. Subsequently, there is a further fractional volume increase while formation of monoclinic ZrO2 is being completed.
Arsenical creosote. VII. Structures of reaction products of arsenic trioxide with some hydroxyaromatic compounds
Authors: Johanson R. 
Published: July 2010

AbstractArsenic derivatives of aromatic compounds having vicinal hydroxyls have been prepared by reacting the compounds with arsenic trioxide in paraffin oil or by fusion of the reactants. The derivatives have been studied by various methods, including i.r., n.m.r. and mass spectrometry, and it is suggested that they are bis(o‐phenylenedioxy arsenic) ethers, with H, CH3 and OH substituted in the 3 and 4 positions of both benzene rings symmetrically, depending on which dihydroxybenzene derivative was used in their preparation.
Fischer–tropsch waxes. III. Indications of molecular order in molten wax
Authors: le Roux J. H. 
Published: July 2010

AbstractAlthough paraffins cannot form liquid crystals, evidence of the existence of some kind of molecular order at temperatures above their melting points can be found in the literature. When the infra‐red spectra of certain Fischer–Tropsch waxes were recorded at different temperatures, it was noticed that the intensity of the 1303 cm−1 band (A1303), which is due to methylene groups in amorphous regions, was abnormally low just above the melting points of the waxes. At higher temperatures the intensity rose to a maximum followed by the normal decline. This effect was shown most strikingly by super‐hard wax, which has a high crystallinity and high average molecular weight.A dilatometric experiment with super‐hard wax showed that the specific volume rises linearly from the melting point (111°) to ∼ 125°. At higher temperatures, although the volume continues to rise linearly, the slope is reduced by 11%. The explanation presented for both phenomena is that bundles of molecules are present above the melting point. They are remnants from crystallites and disappear at ∼ 125°. in the case of super‐hard wax. Upon cooling, however, the ordering of molecules only starts taking place near the congealing point. This is borne out by the linear changes in A1303 and specific volume that have been observed.
Fischer‐tropsch waxes. IV. Qualitative and quantitative investigation of chain branching
Authors: le Roux J. H. 
Published: July 2010

AbstractThe degree of branching of waxes, expressed as the number of branches per 100 carbon atoms, is important because it determines crystallinity, which in its turn influences physical properties. Among several methods available for the study of branching, an infra‐red spectrometric method was chosen. It consisted of the determination of methyl groups. It was also necessary to determine molecular weight.The most serious problem encountered was the variation of the specific absorbance at the chosen frequency (1379 cm−1) with the structural position of the methyl group, which necessitated a thorough qualitative investigation of the branches, using infra‐red, nuclear magnetic resonance and mass spectrometry. It was shown that branches in the Fischer‐Tropsch waxes are almost entirely methyl and that the branching is seemingly distributed statistically along the chains. Calibration was effected with pure n‐ and mono‐methyl paraffins, making the determination of degree of branching possible. This method can be applied to other materials provided that certain structural features about them are known.
Surface area and pore structure of talc‐magnesite
Authors: Girgis B. S. , Girgis L. G. 
Published: July 2010

AbstractThe effect of thermal treatment on talc‐magnesite in the presence of air in the temperature range 500–1000°, was studied by nitrogen adsorption and followed by t.g.a., d.t.a. and X‐ray analysis. From the nitrogen adsorption isotherms, the specific surface area as well as pore‐size distribution was estimated. The surface area increased with temperature, to reach a maximum at 600°. On immersion of the calcination products in water, magnesium hydroxide was formed. Decomposition of the hydration products in air at 450° resulted in solids of relatively higher surface areas, whereas decomposition in vacuo at the same temperature produced more active solids. Surface area of the products produced in vacuo decreased only slightly with the primary decomposition temperature, and they are characterised by sharp pore‐size distribution curves. Surface areas of the products produced in air were dependent on the primary calcination temperature, although they showed pore‐size spectra similar to those of the other products. Products obtained by direct decomposition in air showed wider pore spectra that shifted towards higher pore radii with rise of temperature.
Synthesis of benzoic acid from chlorobenzene under pressure
Authors: Palit S. K. , Tripathy N. 
Published: July 2010

AbstractConversions as high as 76·26% and 80·85% of chlorobenzene to benzoic acid were obtained when chlorobenzene was carboxylated with carbon monoxide and water at high pressure with nickel iodide‐silica gel catalyst (Ni:SiO2 = 50:50) and without any catalyst (thermal) respectively, at the optimum temperature and pressure; these optima were much higher for the latter than for the former process. The lower yield in the catalytic process could be improved to some extent if the catalytic reaction was carried out at a pressure, reached by introducing nitrogen in addition to the usual input of carbon menoxide, almost equal to the optimum pressure of the thermal process.
Dehydration and rehydration behaviour of zinc and magnesium sulphate heptahydrates
Authors: Razouk R. I. , Mikhail R. Sh. , Ghorab H. Y. 
Published: July 2010

AbstractThe kinetics of the isothermal dehydration of zinc and magnesium sulphate heptahydrates were studied both in vacuo and in the presence of air. Decomposition in vacuo followed a first‐order mechanism, while that in the presence of air followed an interfacial mechanism obeying the Avrami–Eroféev equation. In the case of zinc sulphate decomposing in air, the fusion of the salt in its water of crystallisation interfered with the observed phenomena. The energy of activation in both cases was calculated to be comparable to the latent heat of vaporisation of water, and it is suggested that this would measure the heat of desorption of water from the surface of the dehydration product. When decomposition was carried out in vacuo at comparatively elevated temperatures, the process changed to an activated diffusion or surface diffusion. Dehydration in vacuo yielded an amorphous intermediate, as well as final products, whereas dehydration in the presence of air yielded crystalline products. Differential thermal analysis proved the stepwise nature of the dehydration process.The rehydration from the vapour phase was also studied on the dehydration products of both zinc and magnesium sulphate heptahydrates, and it was shown that the rehydration isotherms could be significantly affected by both the extent and the nature of the surface of the dehydration product. The specific surface areas were measured by low temperature adsorption of nitrogen.
Nuclear magnetic resonance cryoscopy. I. A method of purity control
Authors: Herington E. F. G. , Lawrenson I. J. 
Published: July 2010

AbstractA cryoscopic method of purity control is described which uses nuclear magnetic resonance to measure the fraction of liquid molten at a temperature below that at which the sample is completely molten. This method, which offers several advantages over other cryoscopic procedures for purity determination, is demonstrated by measurements on several systems, including phenol containing water or one of the three cresols as impurity.
Nuclear magnetic resonance cryoscopy. II. A method for the determination of solid‐liquid phase diagrams
Authors: Herington E. F. G. , Lawrenson I. J. 
Published: July 2010

AbstractThe study of solid‐liquid phase diagrams by nuclear magnetic resonance cryoscopy is demonstrated by measurements on the systems phenol‐m‐cresol, phenol‐o‐cresol and 1‐methylnaphthalene‐2‐methylnaphthalene. This method enables the true position of the equilibrium solidus to be found, even when the two components are not uniformly distributed in the solid and total equilibrium is not achieved.
Effect of high‐temperature direct‐current electrolysis on properties of hydrous aluminosilicates
Authors: Mackenzie K. J. D. 
Published: July 2010

AbstractThe application of a d.c. potential to kaolinite and halloysite pellets during firing under reduced pressure has been found to produce significant improvements in the hardness, tensile strength, and density of the product. Studies of these properties as a function of voltage, electrolysis time and temperature, and firing atmosphere are reported. X‐Ray and i.r. studies of mullite formation at the electrode faces indicate enhanced crystallinity at the negative electrode. The electrolysis mechanism is thought to involve the removal of residual protons normally present even at high temperatures.
Physicochemical studies on the water‐yeast cells‐gas‐oil system
Authors: Srivastava S. P. , Singh H. D. , Baruah J. N. , Krishna P. V. , Iyengar M. S. 
Published: July 2010

AbstractPhysical characteristics of the hydrocarbon fermentation broth obtained during the microbial synthesis of protein concentrates from mineral oil have been studied. The effect of pH and the action of electrolytes and various organic compounds on the stability of the emulsion were investigated. It has been possible to obtain a fairly stable emulsion containing more than 85% of oil in the internal phase by the use of dry yeast cells. The strong hydrophilic character of the yeast cell membrane and the lowering of interfacial tension between the mineral oil and water are responsible for the unique stability.
Solubilisation of some bituminous coals in quinoline by ultrasonic irradiation
Authors: Kessler T. , Friedel R. A. , Sharkey A. G. 
Published: July 2010

AbstractThe solubilisation of 4 hvab and 1 hvbb coals by ultrasonic irradiation of coal‐quinoline systems at ambient temperature was investigated. The amount of coal solvated was found to be a function of time and particle size. The use of a char prepared at the temperature of maximum coal fluidity increased the amount of material solubilised. There was little difference in the amounts of coal solubilised at 36° and 80°. There was a decrease in the sulphur and ash content of the solubilised coal compared with the starting coal. Quinoline can be re‐used as a solvent with no decrease in solubilisation efficiency.Based on high‐resolution mass spectrometric and infra‐red spectroscopic investigations and particle size measurements of the solubilised material, it appears that the increased solubilisation of coal in quinoline results from a grinding action and not a chemical action.
Epoxidation of ethylenic linkages by chromic acid IV. Oxidation of triaryl olefins by chromium trioxide
Authors: Moussa G. E. M. , Abdalla S. O. 
Published: July 2010

AbstractThe oxidation of 1,1,2‐triphenylbut‐1‐ene by chromium trioxide in acetic anhydride gives 1,2‐epoxy‐1,1,2‐triphenylbutane with fission products and 1,1,2‐triphenylacetylethylene. Cis‐ and trans‐1‐p‐chlorophenyl‐1,2‐diphenylprop‐1‐ene yield crystalline epoxides in satisfactory yields under similar conditions. The epoxides are stable towards aqueous sulphuric acid. 1,1,2‐Triphenylethylene, 1,1‐di‐(p‐chlorophenyl)‐2‐phenylethylene and 1,1‐di‐(p‐bromophenyl)‐2‐phenylethylene are similarly oxidised but the epoxides are hydrated to the glycols by the action of aqueous sulphuric acid.Chromic acid in aqueous sulphuric acid brings about oxidative fission of the double bond without any rearrangement.
Course of oxidation of 1, 1‐disubstituted ethylenes by chromic acid
Authors: Moussa G. E. M. , Eweiss N. F. 
Published: July 2010

AbstractThe oxidation of 1,1‐diphenylethylene by chromic acid gives a fair yield of diphenylacetic acid. 1,1‐Di‐(p‐chlorophenyl)ethylene and 2‐phenylprop‐1‐ene are similarly oxidised to acids which have the same number of carbon atoms as the original olefins. 2‐Phenyl‐3,3‐dimethylbut‐1‐ene and 1,1‐di‐(p‐tolyl)ethylene give abnormal fission products on chromic acid oxidation. The significcane of these results is discussed.
Kinetics of the oxidation of carbon monoxide on a supported ferric oxide catalyst
Authors: Goodridge F. , Nicholson P. J. , Nadim M. 
Published: July 2010

AbstractKinetic studies were made of the oxidation of carbon monoxide to carbon dioxide in a fixed bed of ferric oxide catalyst. It was found that the rate of oxidation, R, is given by the equation R = k1 k1pco/1+(k1/k2)pco where k1, k1 and k2 are constants and pco is the partial pressure of carbon monoxide. This rate law is similar to that derived for the same reaction on a vanadium oxide catalyst. The rate equation reduces to first order for carbon monoxide concentrations < 1 %.
Adhesion test for road surface dressing binders
Authors: Briggs D. K. H. , Croft J. A. 
Published: July 2010

AbstractA study has been made of the adhesion of chippings to a film of road tar, supported on a base plate, under conditions similar to those encountered in surface dressing, but without interlock of stone particles. Chippings are removed by inertial stresses set up in them when a carefully regulated blow is applied to the base plate.A critical adhesion temperature, above which chippings should be applied to road tar, has been shown to be about 32 deg. c below the equiviscous temperature (e.v.t.) for clean, dry basalt chippings; a lower value is shown to apply in the case of PVC‐modified tar.Results indicate that the unit reasonably simulates service conditions and its use is proposed for additional studies.
Formation and surface properties of electron‐emissive coatings V. DTA, ETA and dilatometry studies on some alkaline–earth carbonates
Authors: Judd M. D. , Pope M. I. 
Published: July 2010

AbstractThe decomposition under vacuum of the carbonates of calcium, strontium and barium was investigated by differential thermal analysis (DTA), electrothermal analysis (ETA) and dilatometry.The results indicate that the rates of sintering of the oxide produced by the decomposition of the corresponding carbonate are in the order predicted by their respective Tammann temperatures, i.e. BaO>SrO>CaO. DTA studies on the decomposition of samples of barium carbonate have shown that great care must be taken to ensure that the decomposition is carried out under the highest vacuum attainable, in order to eliminate the formation of a basic carbonate. Further evidence of the formation of free barium by this decomposition process is also reported.
The alleged phospholipid of wool wax
Authors: Morris T. A. , Truter E. V. 
Published: July 2010

AbstractAnalysis of methanolic extracts of wool grease for nitrogen and phosphorus, and laminar chromatography of the ether‐insoluble fraction obtained from the methanol‐soluble portion, showed that wool wax does not contain phospholipids but it does contain traces of polypeptides and inorganic phosphate. These results conflict with the results of other workers, but possible explanations of false conclusions drawn from the latter results are given.
Air‐entraining actions of anionic surfactants in portland cement pastes
Authors: Bruere G. M. 
Published: July 2010

AbstractThe air‐entraining actions of a number of anionic surfactants in cement pastes were studied in order to determine whether precipitated calcium surfactants influence the air‐entrainment process. Air contents of pastes containing both soluble and precipitated calcium surfactants were higher than those containing only soluble calcium surfactants, thus indicating that precipitated material contributed towards air‐entrainment. It was shown further that the precipitated calcium surfactant could re‐dissolve appreciably during mixing and supply additional surfactant ions in solution to replace those adsorbed on cement. It was concluded that these additional ions contributed to air‐entrainment by further adsorption on cement particles and by augmenting the foam capacity of the mixing water.
Sorption of sulphur dioxide by indoor surfaces III.—Leather
Authors: Spedding D. J. , Rowlands R. P. , Taylor J. E. 
Published: July 2010

AbstractThe sorption of sulphur dioxide by a wide range of leather samples has been investigated at a concentration of ∼ 100 μg/m3 using sulphur‐35 dioxide. In general, the sulphur dioxide was sorbed evenly over the leather surfaces, the sorbed sulphur being water‐soluble. The position on the hide from which the leather was taken had no significant effect on the amount of sulphur dioxide sorbed. The total uptake of the gas was reduced by the application of a finish and by dyeing. The penetration of sulphur dioxides into the samples was influenced by the nature of the organic retanning process used, condensed tannins leading primarily to surface sorption. Leather greases were also shown to reduce penetration of sulphur dioxide. Some implications of these results in the degradation of leathers by atmospheric sulphur dioxide are discussed.
Fluidised‐bed fuel‐cell electrodes
Authors: Berent T. , Mason R. , Fells I. 
Published: July 2010

AbstractA study is described of both anodic and cathodic fluidised‐bed fuel‐cell electrodes operating with dissolved reactants. Two different trends were observed. With cathodes, the apparent polarisation decreased with increase in fluidisation and with anodes the apparent polarisation increased with increase in fluidisation. These effects are thought to be due to different reaction mechanisms and the different nature of the bed materials.