bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical aspects of the production of television tube screen. III. The dry screen
Authors: Lines F. 
Published: July 2010

AbstractThe adhesion of phosphor to glass in the dried screen has been measured. It was found to depend on the quantity and composition of the solution left in the screen pores after removal of the bulk of the settling liquid. Adhesion was produced by drying of the solute. Delay between draining and drying allowed gelation to proceed, thereby reducing the quantity of dry binder available.Migration of solution through the screen towards the drying patch, if allowed to proceed for too long a time, caused uneven binder distribution.Measurement of the light output of screens under electron excitation confirmed the usual effect of variation in screen thickness on screen luminescence. Whilst controlling screen thickness, factors in settling were varied, but these factors were found to be irrelevant as long as good screen structure was maintained. Type and purity of potassium silicate had no effect within the usual settling range. Flocculation or very high silicate concentration depressed light output, but could be easily avoided.
Grafting of methyl methacrylate on isoprene rubber
Authors: Waterman J. A. , la Heij G. E. , van Hoorn H. 
Published: July 2010

AbstractMethyl methacrylate has been grafted on artificial isoprene rubber (IR) latex, with use of redox initiation. The properties of latices containing up to 40 phrParts per hundred parts of rubber.
methyl methacrylate (MMA) as well as solid products containing up to 80 phr of this compound were studied. Compared with ungrafted IR latex with the same solids content, the grafted IR latices had a lower viscosity, owing to their particle size being larger. Vulcanised films obtained from the grafted latices showed a considerably higher modulus, particularly at large deformations, than those based on IR or blends of IR with polymethyl methacrylate. by incorporation of certain reinforcing white fillers in the MMA‐grafted IR latices, a further increase in the modulus of the latex films was effected.
Thermosetting resins curing by the arbuzov reaction
Authors: Stark B. P. , Duke A. J. , Martin R. J. 
Published: July 2010

AbstractThe usefulness of the ‘catalytic’ Arbuzov reaction as a curing mechanism for thermosetting polymerisation has been examined, using a range of bis‐(cyclic phosphites). Such a cure is strongly catalysed by Lewis bases.
The reaction of kaolin with fluorides. III. Hydrolysis of silicon tetrafluoride by kaolinite at elevated temperatures
Authors: Semmens B. 
Published: July 2010

AbstractThe reaction between kaolinite and silicon tetrafluoride has been studied over the temperature range 300–700°. Above the dehydroxylation temperature of kaolinite the formation of metakaolinite was accompanied by an increase in sample weight rather than a loss. In the presence of an excess of SiF4 the reaction products showed signs of interaction with one another, possibly to form a fluoroaluminate.
The examination of disperse crystalline phases in polyvinyl chloride
Authors: Michell E. W. J. , Pearson D. G. 
Published: July 2010

AbstractThe examination by microscopy and X‐ray diffraction, of fine crystalline powders embedded in polyvinyl chloride is described. These techniques are applied to an investigation of the stabilising reaction of white lead during thermal degradation of PVC. It is shown that the white lead reacts as a compound, being completely converted to lead chloride by the time hydrogen chloride gas is evolved from the PVC specimen. An unidentified intermediate crystalline phase is also formed. Both this phase and the final lead chloride, nucleate at sites away from the white‐lead stabiliser particles, which indicates that lead compounds must have a solubility in hot PVC plastic. During the thermal degradation neither normal lead carbonate nor gas bubbles have been detected.The PVC fabrication processes cause the stabiliser crystallites to take up preferred orientation and this makes microscopic examination of the crystallites easier, but can cause difficulty in identification by X‐ray diffraction.
Determination of bound styrene in insoluble emulsion polymerised styrene‐butadiene copolymers
Authors: Post Mildred A. 
Published: July 2010

AbstractBound styrene is determined in insoluble emulsion polymerised styrene‐butadiene copolymers by measurement of the 10.3 μm/13.2 μm absorbence ratio using the baseline method. This ratio is obtained from the infra‐red spectrogram of the copolymer. The styrene content is then determined from a standard curve. The standard curve is constructed from absorbence ratios of 10.3 μm/13.2 μm derived from the infra‐red spectrograms of cast films of styrene‐butadiene latices over a range of compositions in which the bound styrene has been determined by nitration of the isolated and extracted copolymers. Styrene content based on nitration is determined from standard curves relating styrene concentration to spectrophotometric absorbence measurements at wavelengths of 285.0 nm, 273.8 nm and 265.0 nm. The source of the styrene for these curves is NBS standard rubber #1500.
Kinetic study of formation of bisphenol a
Authors: Ghosh P. K. , Guha T. , Saha A. N. 
Published: July 2010

AbstractThe condensation reaction of phenol with acetone in an acidic medium to produce bisphenol A has been studied with and without the use of promoters. The promoters used were thioglycollic acid, ethyl mercaptan, butyl mercaptan and hexyl mercaptan. The kinetic study of the reaction shows a first order dependence of the reaction rate individually on phenol and on acetone. The mercaptans greatly enhance the reaction rate whereas thioglycollic acid appears to be only a moderate promoter. The rate‐controlling step of the reaction has been found to be the formation of the intermediate carbinol, 2‐(4‐hydroxyphenyl)‐propan‐2‐ol.
Equilibria and hysteresis in the system Mn2O3Mn3O4O2
Authors: Shenouda F. , Aziz S. 
Published: July 2010

AbstractIn the light of the present and previous experimental observations, the discrepancy between the dissociation pressures and the thermodynamic results of the system 6 Mn2O3 = 4 Mn3O4+O2 is discussed. The degree of fineness and the related lattice defects of the solid phases, the oxygen content of the Mn2O3 modification and the sintering of the fine solid material are thought to be causes of such inconsistency. Less probable is the effect of the mutual solubility of α‐Mn2O3 and α‐Mn3O4.The thermodynamic results for the association of α‐Mn2O3 are given.At given time intervals during a dissociation run, the pressure values are stable and independent of time and can be reached from both directions when it is a matter of small shifts about the equilibrium state. Higher oxygen pressures are attained on combination when dissociation and combination processes are carried out successively in the same run. The difference in pressure decreases with increase of temperature. The results may indicate a hysteresis phenomenon.
Synthesis of formaldehyde and methanol from methane and water in an electrical discharge two‐phase reactor
Authors: Sergio R. , Thornton J. D. 
Published: July 2010

AbstractThe synthesis of formaldehyde and methanol from methane and water vapour initiated by a d.c. discharge has been carried out in a two‐phase gas‐liquid reactor in which liquid water was present as a pool covering one electrode. Decomposition reactions, responsible for the low energy efficiency, are limited by a shorter residence time of the soluble products in the gas phase. The experimental results, when compared with those obtained in the absence of water, show a considerable increase in the energy yield.
Length change characteristics of Ca(OH)2 compacts on exposure to water vapour
Authors: Ramachandran V. S. , Feldman R. F. 
Published: July 2010

AbstractThe presence of large quantities of Ca(OH)2 in hydrated Portland cement suggests that a study of the length change‐sorption characteristics of Ca(OH)2 in the form of compacts should provide useful information.Length change‐sorption data were obtained for water from 0 to 76% RH and various cycling experiments between 0 to 58 and 0 to 93% RH were performed during which length change data were obtained. Preliminary experiments were also performed in relation to the carbonatation of Ca(OH)2 compacts.Large irreversible shrinkages were observed while repeatedly determining the isotherms during the cycling experiments and it is suggested that these were the result of ionic diffusion from the points of contact of crystallites and the pulling together of these crystallites by van der Waals forces.The carbonatation of calcium hydroxide also produced shrinkage and it is considered that this could also be due to van der Waals surface forces.
Solubility of chlorine in a brine solution at different pH values
Authors: Bott T. R. , Schulz S. 
Published: July 2010

AbstractThe solubilities of chlorine in a solution containing 250 g/litre of sodium chloride, at different pH values (in the range 1–2.5) have been experimentally determined at different chlorine partial pressures and at temperatures of 50° and 75°. The results show some slight divergence from data previously reported in the literature but these were obtained by a different procedure.
Formation and reactivity of nitrides I. Review and introduction
Authors: Glasson D. R. , Jayaweera S. A. A. 
Published: July 2010

AbstractMethods of nitride production are summarised and their thermodynamics surveyed. Crystal structures and types of bonding in binary and ternary nitride compounds are classified and discussed. Kinetics of nitride formation are related to structural changes in the materials, which control diffusion of metals and nitrogen and cause nitride scaling. Metal nitridation with ammonia and nitride formation during ammonia synthesis are discussed.Information so far available on the sintering of nitrides and its effect on their chemical reactivity is reviewed. This effect is influenced by additives or impurities such as oxides formed by partial nitride hydrolysis and oxidation. Sintering and hot pressing increase the resistance of nitrides to hydrolysis and oxidation, so that they become more suitable for use as refractories. Often, corrosion resistance of nitride layers on metal surfaces is impaired by poor scaling resistance in air or oxygen at comparatively low temperatures. The kinetics and products of oxidation of nitrides so far studied, notably AlN, TiN and UN, depend mainly on the intrinsic reactivity of the material and the available surface at which oxidation can occur.Subsequent work will be concerned with changes in phase composition, surface area and crystallite and aggregate sizes and their correlation with production, sintering, hydrolysis and oxidation conditions for single and mixed nitrides. Suitable experimental techniques are summarised in this paper.
Measurement of the permeability of thick membranes to liquefied hydrocarbons by a radioactive tracer technique
Authors: Evans R. 
Published: July 2010

AbstractA radioactive tracer technique has been devised to measure the permeability of thick membranes and layers of synthetic rubbers and glass‐fibre laminates to liquefied hydrocarbons. The technique involves the use of the tritium‐labelled hydrocarbon, prepared by treating the appropriate Grignard reagent with tritiated water. The labelled hydrocarbon is transferred to a thermostatted permeability cell. Permeate is trapped in a vial which contains liquid scintillation phosphor and is cooled in liquid air. The trapped permeate is measured by liquid scintillation counting of the sealed vial. Such measurements, made over an appropriate period, allow permeability constants to be calculated.Propane transfer rates down to 10−10 g/h have been measured, with membranes of thickness ranging from about 0·5 to 1·5 mm, giving permeability constants of the order of 10−11 g cm−1 h−1 atm−1. Abnormal rate/time curves have been found for some membranes.Factors affecting the accuracy of the measurements, and the safety precautions necessary, are discussed. Finally, extension of the technique to the study of hydrocarbons of low boiling point such as methane is considered.
Mechanism of the carbonatation shrinkage of lime and hydrated cement
Authors: Swenson E. G. , Sereda P. J. 
Published: July 2010

AbstractCarbonatation of hydrated lime compacts produces shrinkage and changes in mechanical properties comparable with those found in similarly treated compacts of bottle‐hydrated cement and samples of hardened Portland cement paste. From experimental results obtained with the simpler lime system a mechanism for carbonatation shrinkage is proposed that postulates a through‐solution reaction and induced cycles of wetting and drying.Experiments on compacts of bottle‐hydrated cement show that carbonatation of the ‘combined lime’ is at least as rapid and extensive as the carbonatation of the ‘free lime,’ and that contrary to current opinion the former reaction results in even greater carbonatation shrinkage. The mechanism for carbonatation shrinkage of this system is considered to be connected with dehydration and polymerisation of the hydrous silica product of carbonatation.
Some molten ionic oxides as chemical reagents
Authors: Araten D. 
Published: July 2010

AbstractMolten ionic oxides possess important desirable properties: thermal stability, and useful chemical properties resulting from their acid or basic behaviour, i.e., from their capacity to accept or donate an oxygen ion, and, in several cases, relatively low melting points, well below 1000°c.Bismuth trioxide was found to effect a two‐temperature decomposition of ammonium chloride, yielding ammonia and hydrogen chloride. Molten antimony trioxide was found to attack rock phosphate and convert part of the phosphate to a water‐soluble form. Molten lead monoxide was found to dissolve calcium oxide readily, to dissolve chromic sesquioxide, to decompose chromite ore and to permit an extraction of iron‐free lead chromate into an upper layer of molten alkali chloride. Addition of lead sulphide to a lead monoxide melt caused formation of elemental lead and lead sulphate.Vanadium pentoxide was found to decompose ammonium chloride, yielding first, hydrogen chloride and then, ammonia. The reaction of a vanadium pentoxide melt with rock phosphate, studied in some detail, resulted in water‐solubilisation of the phosphate. The product formed in the melt is probably a calcium phosphate vanadate, from the aqueous solution of which calcium can be precipitated by ammonium carbonate; the ensuing ammonium phosphate and vanadate solution can be separated by known methods, permitting recovery of the vanadium pentoxide, and yielding ammonium phosphate.
New low‐density ceramic material for packing fractional distillation columns
Authors: Castellucci N. T. , Krouskop N. C. 
Published: July 2010

AbstractThis paper presents a general comparison between glass beads and new low‐density ceramic spheres as packing materials for fractional distillation columns. The light‐weight ceramic spheres have higher through‐puts, lower pressure drops, better separating power and higher wettability than glass beads.
Sorption of sulphur dioxide by paper
Authors: Edwards C. J. , Hudson F. Lyth , Hockey J. A. 
Published: July 2010

AbstractSulphur dioxide is sorbed by paper and slowly converted to sulphuric acid; the presence of this severely reduces the useful life of the material. The sorption (‘pick‐up’) of sulphur dioxide has been investigated for a representative range of papers for exposures lasting many months at concentrations approaching those found in polluted urban atmospheres.It was found that the relative humidity does not significantly affect the long‐term pick‐up rate and that this rate remains constant for prolonged exposures, being proportional to the square root of the gas phase sulphur dioxide concentration. Rosin size increases markedly the long‐term rate while certain other paper additives, e.g. Turkey Red Oxide and Anatase, have no such effect.
Continuous multistage fractional crystallisation I. laboratory investigation
Authors: Betts W. D. , Freeman J. W. , McNeil D. 
Published: July 2010

AbstractThe application of a laboratory scale rotating helix crystalliser to the separation of a number of organic and aqueous systems is described. The results show separations equivalent to several stages with systems exhibiting the phenomenon of solid solution and the recovery of components in high purity from multi‐eutcetic systems.
Distribution of hydrochloric acid between tri‐n‐butyl phosphate and water
Authors: Hanson C. , Patel A. N. 
Published: July 2010

AbstractThe distribution of hydrochloric acid between water and 40 vol.‐% solutions of tri‐n‐butyl phosphate (TBP) in six diluents and also between water and 20. 40 and 60 vol.‐% solutions of TBP in odourless kerosene and pure TBP at 20°, 30° and 50° has been studied to find the effects of temperature, diluent and TBP concentration on the extractability of hydrochloric acid and on third‐phase formation.
Kinetics of deposit formation from hydrocarbons. III. Heterogeneous and homogeneous metal effects
Authors: Taylor W. F. 
Published: July 2010

AbstractThe nature of metal surfaces (‘heterogeneous’ metals) and the presence of metal complexes (‘homogeneous’ metals) both markedly influence the rate of formation of deposits from hydrocarbon jet fuels at 200 to 500° F in the presence of oxygen. Copper surfaces and titanium alloy surfaces which contain vanadium were found to be particularly deleterious. The addition of 50 ppm metal using various metal acetylacetonates to the hydrocarbon fuel increased the rate of deposit formation by a factor of from 40 to 120 at 300° F. Copper acetylacetonate produced a higher rate of deposit formation than iron, nickel or cobalt acetylacetonates. The relative rate of deposit formation depended on the square‐root of both the vanadium content of the titanium alloys and the concentration of a ferric acetylacetonate in the fuel.
Surface chemistry of the calcination of gelatinous and crystalline aluminium hydroxides
Authors: Aldcroft D. , Bye G. C. , Robinson J. G. , Sing K. S. W. 
Published: July 2010

AbstractThe surface properties of a range of aluminas, obtained by calcination of crystalline and gelatinous aluminium hydroxides at temperatures from 300° to 1000° and characterised by X‐ray powder diffractometry, have been examined by nitrogen adsorption.On calcination the hydroxides exhibited two distinct types of behaviour which can be related to their texture. Crystalline hydroxides underwent a pronounced activation, the increased surface area being almost wholly confined to the small pores (micro and transitional pores) formed on dehydration. Gelatinous hydroxides, on the other hand, had high surface areas before calcination and these underwent a progressive diminution in the temperature range studied.The structures obtained on calcination depended to a marked degree on the crystallinity of the starting materials. Between 500° and 800°, the amorphous hydroxide and poorly organised pseudoboehmites gave ill‐defined γ‐aluminas whereas the crystalline trihydroxides gave well‐defined η‐ and θ‐aluminas. At 1000°, the product from the amorphous hydroxide still retained a surface area of 132 m2/g, this high residual area being in character with the slowness of the conversion to δ‐and α‐alumina.An empirical approach is used to analyse the adsorption data in terms of three mechanisms of adsorption: monolayer‐multilayer coverage, capillary condensation, and micropore filling.
Oxidation of thiols in gas‐liquid systems. I. Reaction in the absence of added metal catalysts
Authors: Cullis C. F. , Hopton J. D. , Trimm D. L. 
Published: July 2010

AbstractStudies have been made of the kinetics of the reaction with oxygen of several simple aliphatic and aromatic thiols in alkaline solution and in the absence of added metal catalysts. The results have been shown to be markedly affected by trace amounts of impurities, and the kinetics of the reaction have been measured under conditions of the minimum impurity levels obtainable. Under these conditions in the early stages of reaction, the rate law with, for example, ethanethiol has been found to be:
equation image
which after ≈ 10–30% of reaction changes approximately to:
equation image
Values of the energies of activation and pre‐exponential factors for the oxidation of ethanethiol have been determined and investigations have been made of the effect on the reaction kinetics of the efficient removal, and of the addition of trace quantities of metals.
Observations on calcium sulphate dihydrate formed in media rich in phosphoric acid. II. Derived calcium sulphate hemihydrate
Authors: Adami A. , Ridge M. J. 
Published: July 2010

AbstractA study was made of the properties of calcium sulphate hemihydrate prepared by the calcination of dihydrate formed in a medium containing finally 29·4% P2O5 and 5·6% H2SO4. When the original dihydrate had been precipitated in uncontaminated acid, hydration of the hemihydrate seemed to be normal. However, when the medium of precipitation contained hydrofluoric acid and salts of iron and aluminium, the calcination product was not susceptible to a retarder that markedly affected the hydration of commercial calcined gypsum. The presence of P2O5 did not appear to be responsible for this type of defect.The bulk volume and water requirement seemed to be normal when the crystal forms of the component grains were normal.Observations are made on the strengths of the derived cast gypsum.
Brittle point of road tar
Authors: Briggs D. K. H. , Croft J. A. 
Published: July 2010

AbstractAn automated version of the Fraass brittle‐point test has been constructed which gives easier operation and better reproducibility than either an earlier modification or the original test.The brittle‐point data for road tars have been shown to vary linearly with the equiviscous temperature of the materials. The use of the test to study the modification of road tar is illustrated, and it is proposed for the examination of the effects of weathering.
Ageing of some commercial oxide powders on storage
Authors: Giles C. H. , Easton I. A. , Trivedi A. S. 
Published: July 2010

AbstractSome samples of technical grade silica and titania on storage for several years at room temperature show loss of apparent surface. The loss is attributed to dehydration of surface hydroxy‐groups. This can cause adhesion and aggregation of particles whereby the surface measured both by nitrogen and by dyes decreases, and, in some cases, causes a loss of surface reactivity.With heating at temperatures up to 250°, the loss of apparent surface of silica is increased, but that of titania is partly restored. It is suggested that these effects may influence specific surface measurements made by vapour phase adsorption if high temperature out‐gassing is employed.
Ultra‐violet absorption spectra: 4‐hydroxy coumarins
Authors: Mehta M. J. , Hegde R. S. , Bhatt R. A. , Patel D. J. , Bafna S. L. 
Published: July 2010

AbstractThe ultra‐violet absorption, in the range 250 mμ—350 mμ, of twelve 4‐hydroxy coumarins in methanol and in 10% aqueous methanol over a range of pH, has been studied and discussed.