bluuebunny/crossref_metadata_2025_split huggingface dataset:
Density and viscosity of ammonium nitrate, ammonium nitrate–potassium chloride and ammonium nitrate—ammonium phosphate melts
Authors: Booth D. H. , Vinyard V. C. 
Published: July 2010

AbstractThe results of density and viscosity measurements are given for ammonium nitrate and the salt mixtures ammonium nitrate—potassium chloride and ammonium nitrate‐ammonium dihydrogen phosphate. The latter system is complicated because of the formation of non‐ortho phosphates and the results obtained refer to the equilibrium mixture obtained after heating for 3 h at 180°c. After this treatment, about 40% of the phosphate was converted to non‐ortho forms.The density of ammonium nitrate is given by:

for values of t between 170°c and 190°c. Similar relationships can be deduced for the solutions.The viscosity of ammonium nitrate, in centipoises, is given approximately by:

for values of T between 443° and 453° k. Similar relationships hold for the nitrate—phosphate solutions.
Reduction of the calcite content of ground shale by liquid—liquid particle transfer
Authors: Coleman R. D. , Sutherland J. P. , Capes C. E. 
Published: July 2010

AbstractThe removal of calcite from a naturally occurring shale is described. The technique used involves making the calcite particles hydrophobic by ball‐milling the shale in aqueous suspension in the presence of sodium oleate conditioner. The calcite particles are then selectively absorbed by a viscous petroleum oil which is brought into contact with the suspension. Calcite removal was improved by increasing conditioner concentration, time of grinding and oil/suspension contact time. Some of the advantages and disadvantages of the process are pointed out.
Reactivity of lime and related oxides. XVII. Sulphating of lime with magnesium and aluminium sulphates
Authors: Glasson D. R. , O'Neill P. 
Published: July 2010

AbstractLime water and solid hydrated lime have been sulphated with magnesium and aluminium sulphate solutions. Changes in phase composition and sulphating rates are followed from pH (glass electrode) and conductivity measurements. The crystallinities of the products have been compared with calcium sulphate dihydrate precipitated directly from solution by double decomposition and subsequently aged.The reactions with the solid hydrated lime are not appreciably impeded by the insoluble products, magnesium and aluminium hydroxides, which are very finely divided. These compounds provide additional surface on which most of the gypsum can form a gel when the gypsum solution saturation ratios have become sufficiently high.The small amounts of gypsum ultimately separating out from the lime water have crystallinity inferior to the larger amounts formed from the solid hydrated lime. Both are still inferior to gypsum from acid‐sulphated lime, and are more comparable with gypsums precipitated from calcium nitrate in acidic media containing concentrations (±0.1 %) of albumen, or from calcium chloride in neutral media. Slower gypsum precipitation from calcium chloride with sulphuric acid (as in the manufacture of ‘Pearl hardening’) gives a more consistent degree of crystallinity.
Extraction of tar acids from tar oils by aqueous acetamide
Authors: Nair C. S. B. , Sen D. K. , Basu A. N. 
Published: July 2010

AbstractAqueous acetamide has been found to be a good solvent for the extraction of tar acids from low temperature carbonisation tar oils. Saturated acetamide solution at 15–30° in the molar ratio acetamide/tar acids of 3 : 1 effects a recovery of about 90% of tar acids originally present in the oil in two extraction stages. The tar acids are obtained in 77% purity, the impurities consisting of neutral oils and tar bases. Re‐extraction with light petroleum can raise the purity of tar acids to 94%. Tar acids can be separated from the purified acetamide extract by suitable dilution with water.The system tar acids—(bases + neutral oils)—saturated aqueous acetamide has been studied. It has been shown that three theoretical counter‐current extraction stages are required to effect a recovery of 95% of tar acids from a feed oil containing 45% tar acids. 98% recovery of the tar acids could be achieved in four stages.
The characterisation of aluminium hydroxide gels by nitrogen adsorption
Authors: Bye G. C. , Robinson J. G. , Sing K. S. W. 
Published: July 2010

AbstractAluminium hydroxide gels with a range of textures have been prepared by the hydrolysis of aluminium s‐ butoxide with water, aqueous ethanol and aqueous glycerol. Crystallisation was permitted to take place to varying extents by ageing of precipitates in their mother liquors at room temperature.Adsorption isotherms on the outgassed gels were of Types II and IV of the Brunauer classification. An examination of the data by plotting reduced isotherms (V/Vm versus P/Po) revealed the existence of reversible capillary condensation on some of the hydroxides, although the isotherms were of Type II.The Lippens de Boer t method has been found useful in locating the onset of capillary condensation in an adsorption isotherm, but the t‐plot can be misleading with samples that have a spread of pore dimensions extending into both the micro‐ and transitional‐pore regions. This situation appears to arise in pseudoboehmites aged for extended periods so that cementation is extensive.The principal factors influencing the texture of the gels appear to be the extent of crystallisation and the amount of inter‐particle cementation. Thus amorphous material prepared in water was found to be porous whereas that precipitated in glycerol, which apparently protects the surface of the primary particles, was non‐porous (or macro‐porous). Transitional pore systems with the best definition were obtained with pseudoboehmites, especially with those formed by ageing in aqueous ethanol. In water, the ready conversion of pseudoboehmite to low‐area, non‐porous, bayerite is a complicating factor.
Aliphatic hydrocarbons in a low‐temperature tar
Authors: Spence J. A. , Vahrman M. 
Published: July 2010

AbstractThe total aliphatic hydrocarbons from a low‐temperature tar were separated into four groups, each consisting of a similarly wide range of molecules (approximate boiling range of each, 175°–500°): (a) n‐alkanes; (b) branched‐chain alkanes and cycloalkanes; (c) straight‐chain alkenes; and (d) branched‐chain alkenes and cycloalkenes. In (a), n‐alkanes, and in (c), alk‐1‐enes, trans‐alk‐2‐enes and cis‐alk‐2‐enes from C10 to C37 were identified and quantitatively estimated. Group (b) contained pristane and phytane among the few predominant branched‐chain species present, and molecules with isopropyl groups and single and condensed saturated rings. Group (d) was predominantly mono‐olefinic, the double bonds probably being in the terminal position in alkyl chains; isopropyl groups were also present.
Stability of ferrous hydroxide in aqueous suspension at 300°c
Authors: Castle J. E. , Thompson R. G. 
Published: July 2010

AbstractThe decomposition of ferrous hydroxide in aqueous suspension at 300° and in PTFE containers has been studied. The reaction rate is slow but is catalysed by nickel and platinum. This explains the results of earlier workers who have found the decomposition of ferrous hydroxide supported in metallic containers to be rapid.
H2s in natural gas: tolerance of some national acceptance tests
Authors: Williams A. F. , Lom W. L. 
Published: July 2010

AbstractTraditionally, limits on H2S concentration in town gas have been fixed on the basis of non‐discoloration of lead acetate paper when this is exposed to the gas in a specified manner. Most countries specify their own particular apparatus and conditions for carrying out this test. The limiting concentration of H2S which produces a positive discoloration of the lead acetate paper was investigated with special reference to the U.K., French and German national gas acceptance tests, using Dutch natural gas in both the saturated and dry condition in every case.H2S was introduced into the gas at a controlled rate by a dynamic line blending procedure. The actual concentration of H2S present was checked by an automated version of the methylene blue colorimetric procedure.The U.K. tests gave borderline fails at 1.3 and 1.2 ppm for dry and saturated gas, respectively. These results differ markedly from those obtained with the French and German test methods. It may be inferred, therefore, that the maximum acceptable H2S concentration in gas is best fixed by a numerical limit, which is in line with true technical needs, rather than by a qualitative procedure which can be different for different parts of the same distribution system.
Humidity control in the laboratory using salt solutions—a review
Authors: Young J. F. 
Published: July 2010

AbstractThe relative humidities maintained over saturated and unsaturated salt solutions and of some salt hydrate mixtures have been collated from the literature over a wide range of temperature. Results are presented for 38 saturated salt solutions, and details listed for salts which are recommended as suitable for humidity control. The control of humidity in the laboratory by the use of salt solutions is critically discussed.
Non‐ideal kinetics in free‐radical polymerisation
Authors: Smith D. G. 
Published: July 2010

AbstractThe reasons for polymerisation rates not conforming to mathematically predicted relationships are reviewed. Such non‐ideal kinetics may result from one or more of the following causes: invalid basic assumptions, degradative transfer, effect of monomer concentration on rate of initiation, diffusion control of termination, and formation of electron‐donor/acceptor complexes. Details of the characteristics of each effect are given.
Thermal dissociation of Ca(OH)2 at elevated pressures
Authors: Samms J. A. C. , Evans B. E. 
Published: July 2010

AbstractThe equilibrium Ca(OH)2 ⇌ CaO+H2O has been studied at pressures of steam up to 50 bars and at temperatures of up to 800° C. The dissociation pressures determined are in agreement with the data derived by some previous workers at pressures of less than one bar but they conflict with data published for higher pressures. The results can be expressed by the relation
equation image
over the range 530–800°c.
Estimation of the effective thermal conductivities of two‐phase media
Authors: Ratcliffe E. H. 
Published: July 2010

AbstractA nomogram scaled in logarithmic units, and a chart are provided for estimation of the effective thermal conductivities of two‐phase media. The former is useful for precise prediction, and the latter as an approximate guide to probable limiting values. The basis is a logarithmic equation proposed by Woodside & Mesmer, biased empirically following the study of about 150 experimental results for two‐phase media. The practical uses are numerous, e.g. estimations of the conductivities of filled plastics, filled rubbers; metal, ceramic and other powders in fluids or gases; ocean sediment; waterlogged and frozen soil, and other materials.
Ion‐exchange properties of brown algae I. Determination of rate mechanism for calciumhydrogen ion exchange for particles from Laminaria hyperborea and Laminaria digitata
Authors: Myklestad S. 
Published: July 2010

AbstractAlgal particles from Laminaria hyperborea stipes and Laminaria digitata were exposed to a stream of hydrochloric acid in a continuous flow apparatus, and the ion‐exchange process Ca/H was investigated. The exchange rate was shown to depend upon such factors as acid concentration, particle size, agitation and time of acid residence.The results show that the exchange rate followed a first‐order reaction in the conditions used, and the exchange velocity was proportional to the logarithm of the hydrochloric acid concentration. Evidence is given which indicates that the exchange process is governed by a film‐diffusion mechanism, and the diffusion of calcium across a thin liquid film enveloping the particle is suggested to be the rate‐determining step. Exchange experiments with particles from Ascophyllum nodosum show that another rate mechanism has to be considered in this case.
Hydrophilation of glass surfaces II Reaction of quaternary ammonium compounds with surface hydroxyl groups
Authors: Blackman L. C. F. , Harrop R. 
Published: July 2010

AbstractThe reaction mechanism for the adsorption of hexadecyltrimethylammonium bromide (HTAB) on silica was investigated. Although measurements of the effects of pH and concentration of HTAB tended to support a cation exchange mechanism, infra‐red analysis suggested that the adsorption was associated with a charge‐transfer type of reaction.
Thermodynamic properties of methanol–benzene mixtures at elevated temperatures
Authors: Butcher K. L. , Medani M. S. 
Published: July 2010

AbstractThe total pressure and the compositions of the vapour and liquid phases of the methanol–benzene system have been determined under equilibrium conditions at 100°, 120°, 140°, 160°, 180°, 200° and 220° for ten levels of concentration. The corresponding activity coefficients of methanol and benzene are reported; their values indicate that the equilibrium data are thermodynamically consistent.An azeotrope is found at all temperatures, its methanol content increasing as the temperature is increased. The relationship log Paz = 6·5098—(1,766/T) expresses the interdependence of the azeotrope vapour pressure Paz(lb/in2 abs.) and temperature T(°K).Estimates of integral heat of mixing (HE) and entropy change due to mixing (SE) as functions of liquid composition (xmeth) have been made from the excess free energy of mixing GE,(T) xmeth functions. Both HE and SE at a given x are positive increasing functions of temperature. These phenomena are discussed in terms of the dissociation of methanol ‘polymer’ and the formation of benzene–methanol ‘complexes’.
Novel process cycle for para‐substituted benzene derivatives
Authors: le Count D. J. , Reid J. A. W. 
Published: July 2010

AbstractA novel cyclic process produces p‐cresol from toluene; toluene with iodosotoluene (derived from iodo‐toluene) gives the intermediate ditolyliodonium salt converted by catalysed hydrolysis into cresol and iodotoluene (which is recycled as ‘catalyst’.) In the final product, o‐cresol content is low and m‐cresol is undetectable. The process reaches a steady state independent of the o‐/p‐isomer ratio of the iodotoluene ‘catalyst’. In a similar way, p‐chloronitrobenzene can be made by reaction of di‐(p‐chlorophenyl)iodonium salt (derived from chlorobenzene and chloro‐iodosobenzene) with nitrite ions.
Precipitate Flotation II. Separation of palladium from platinum, gold, silver, iron, cobalt and nickel
Authors: Mahne E. J. , Pinfold T. A. 
Published: July 2010

AbstractPalladium is completely removed from 5 × 10−5 M‐PdCl2 solutions using the new technique of precipitate flotation of the second kind, in which no surfactant is used to float precipitates. Recoveries were best at pH 1–2 and were not markedly dependent on temperature. Increase in ionic strength had no deleterious effect, unlike conventional precipitate flotation. Palladium can be completely separated from a 400‐fold excess of nickel, a 100‐fold excess of platinum, iron and cobalt, a 10‐fold excess of gold but not from silver in the presence of chloride ions. Equimolar amounts of palladium, nickel and platinum were completely separated from each other by successive flotations. Photographs taken of the bubbles during flotation showed that, at a flow‐rate of 3.1 litre/hour, a mean surface area of 2.07 metre2 passed through the cell per minute.
Production of Escherichia coli as a source of nucleic acids
Authors: Elsworth R. , Miller G. A. , Whitaker A. R. , Kitching D. , Sayer P. D. 
Published: July 2010

AbstractPresent‐day chemical and physical studies of the nucleic acid system of bacteria frequently call for quantities of cells which are beyond the capacity of traditional culture methods such as that of the shake flask. The case is therefore argued for an increased use of stirred deep cultures because a greater rate of output, at a higher cell concentration and with improved control of cultural conditions can be achieved. For the isolation of deoxyribonucleic acid and transfer ribonucleic acid, low growth‐rate cells should be the most prolific source: whereas for ribosomes, ribosomal ribonucleic acid and messenger ribonucleic acid, high growth cells should give bigger yields. It is concluded that the information is somewhat obscure on what are the best growth conditions for the production of the related‐enzymes.A batch method for producing low growth‐rate cells of Escherichia coli, in lots of 1 kg dry wt., is then described, followed by a continuous method for producing high growth‐rate cells, with an output of 3 kg of dry cells per day. Both cultures have been designed to give maximum yield of cells by promoting maximum assimilation of the carbon substrate. From the point of view of designing a culture, the section dealing with the continuous process discusses the rationale of medium formulation, the calculation of aeration requirements and briefly reviews earlier work on the kinetics of continuous culture.
Development of a graphite (HX30) with improved gas diffusional characteristics
Authors: Longstaff B. , Jenkins T. R. , Morris J. B. , Graham L. W. 
Published: July 2010

AbstractThe specification of a graphite suitable for DRAGON fuel tubes which operate on the ‘back‐sweep’ purge principle includes the two requirements: (i) the viscous permeability constant B0 < 3 × 10−11 cm2, and (ii) the fission‐gas transmission coefficient D' < 1 × 10−6 cm2/sec at 20 atm., 7500, and 2 psi pressure drop. Calculations, based on the results of a study of the counter‐diffusion of gases in graphite, suggested that, providing the first criterion was satisfied, the second requirement would be met by a material whose pores were on the average at least 5·5 μm in diameter.A series of experimental graphites based on grists of scrap nuclear‐grade graphite was made with the object of producing artefacts whose pore sizes were in the region of 10 μm, without exceeding the specified limit on permeability. After several adjustments to the size distribution of the grist, one was obtained which yielded an artefact which, after subsequent pitch impregnation, satisfied the reactor specification. The family of graphites based on this particular grist is known as HX30. A second series of experiments demonstrated that this material could be made in full‐sized rods 8 ft long by 3·25 in. dia. Any of four baking routes was possible, depending on whether the primary bake and the re‐bake after impregnation were carried out under atmospheric pressure or at 100 psig. An appropriate number (1 to 3) of impregnations yielded an acceptable graphite.The superior properties of HX30 are considered to be due chiefly to the exclusion of fines (below 300 BSS mesh) from the grist but the nature of the grist (graphite and not coke) and the use of re‐extrusion are probably also significant. The original theoretical approach appeared to be largely vindicated by the pore‐size distribution of the successful product.
FOrmation and reactivity of oxides and basic salts. I. Basic magnesium chlorides and sulphates
Authors: Glasson D. R. , O'Neill P. , Sheppard Margaret A. 
Published: July 2010

AbstractReactions of lime and magnesia with magnesium chloride and sulphate have been studied in relation to industrial processes, namely, extraction of magnesium from sea‐water and production of Sorel‐type cements. Variations in phase composition, surface area and crystallite and aggregate sizes of the products have been correlated with experimental conditions.The solid limes react rapidly with the more dilute magnesium salt solutions, and the precipitated magnesium hydroxides are much more finely‐divided. Basic magnesium salts initially formed are decomposed subsequently to hydroxide as the pH becomes stabilised at higher values. Greater concentrations of magnesium chloride give more extensive basic salt formation and prevent all of the lime going quickly into solution. Similar products are given with solid magnesium hydroxide and magnesium chloride and sulphate solutions.The Sorel‐type cements obtained from magnesium oxide and the more concentrated chloride solutions set appreciably, even before loss of surface through final ageing. They show two distinct phases: (a) irregular grains of 10–50 μm diameter, and (b) acicular or tabular crystals up to 20μm long, mainly in radiating growths. By contrast, the magnesium oxysulphate crystals are not so elongated and the cements set with considerable loss of surface area, giving interlocking structures in which 20–50 μm‐diameter grains are often ‘fused’ together as larger 400–500 μm aggregates.
Soot formation in ethylene and propane diffusion flames
Authors: Dearden P. , Long R. 
Published: July 2010

AbstractSmall samples of gas have been withdrawn from the luminous regions of the diffusion flames of ethylene and propane burning on a Wolfhard Parker burner and these have been analysed by gas chromatography.In general, the parent hydrocarbon is rapidly decomposed on approaching and within the luminous region, acetylene being the major hydrocarbon product found. The concentration of acetylene falls rapidly near the interface with the oxidation zone suggesting that the main hydrocarbon oxidised in the latter is acetylene.The rates of soot collection, the uncorrected temperatures in the flames and the concentration of stable hydrocarbon species have also been measured when oxygen, hydrogen and acetylene respectively were added to the fuel stream. Sooting rates and uncorrected flame temperatures have also been measured when the ‘oxygen index’ of the ‘air’ supply was varied, and it has been found that the sooting rate for both fuels increases with an increase in ‘oxygen index,’ the rate of increase falling off, however, at higher values.Oxygen, when introduced into the fuel, leads to increased temperatures and sooting rates in the case of ethylene and to increased temperatures but decreased sooting rates in the case of propane. The sooting rates of flames of ethylene with acetylene or oxygen as additives increase linearly with the area under the acetylene concentration profile in the luminous zone (measured at a height of ∼ 5 mm above the burner). This area is proportional to the amount of acetylene present in the luminous zone at this height, which corresponds roughly with the onset of luminosity. Acetylene thus appears to be the major stable species via which soot is formed in such flames.Propane flames with oxygen as additive to the fuel, however, behave differently in that although there is an increase in temperature and in the amount of acetylene in the luminous zone the sooting rate decreases. This discrepancy remains unexplained and requires further investigation.
Isothermal vapour–liquid equilibria for the binary system benzene–n‐octane
Authors: Elshayal I. M. , Lu B. C.‐Y. 
Published: July 2010

AbstractVapour–liquid equilibrium data were determined at three isothermal conditions for the binary system benzene–n‐octane using a modified Gillespie still. Non‐ideality of the vapour phase was evaluated and log γ values were correlated.
Studies on the preparation of calcium sulphate hemihydrate by an autoclave process
Authors: Combe E. C. , Smith D. C. 
Published: July 2010

AbstractTo enable further work to be carried out on the hydration of hemihydrate plasters, materials purer than the available commercial plasters and with reproducible properties were required. As a first stage in the attempted preparation of such materials, the process variables in the autoclave dehydration of gypsum were investigated. Methods of treating the gypsum to ensure reproducibility of particle size and for removing other hydrates of calcium sulphate from the prepared materials were developed. It was found possible to prepare samples of a purer hemihydrate, and the reproducibility of the properties of this material has been studied.