Materials Literature
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A study of the velocity autocorrelation function for hard spheres over the entire fluid density region shows that deviations from exponential behavior are small. At very low density a small positive deviation is found which is accounted for in the Boltzmann theory of the self-diffusion coefficient. At higher densities…
Abstract The thermal degradation of polypropylene was investigated in the presence of polyglycidyl methacrylate (PGMA) by the use of an extruder under a nitrogen atmosphere. PGMA was found to be effective as an accelerator for the thermal degradation of polypropylene. The accelerating effect of PGMA was attributed to…
The purpose of the persent work is to evaluate the heat of formation of uranium sesquinitride, U2N3. The U2N3 phase is known to form a single solid solution with UN2, while the U2N3 compound with minimum N/U ratio is in equilibrium mith UN under a given condition of temperature. The heat of formation for the terminal…
The galvanomagnetic parameters ρ123, ρ1111, ρ1133, ρ1131, and ρ1122 have been measured at 77°K for two samples of p-type (Bi2Te3)5(Bi2Se3)1 (Sb2Te3)18 and the results fitted to a six-ellipsoid model similar to that proposed for Bi2Te3. An anomalous rise in the Hall coefficient with temperature and an apparent change i…
The design of an electron velocity analyser, based on an electrostatic einzellinse which incorporates a fine mesh in the centre electrode, is described. Measurements made on a low-energy electron beam show no sign of any broadening of the emission velocity spectrum, i.e. of the so-called `Boersch effect'.
Calcium aluminate and calcium silicate hydrates were formed in mixtures of bentonite with water and various types of lime which had been sealed and cured for up to three years at 23°± 2°C and 100% relative humidity. Methods of analysis were X‐ray diffraction and electron microscopy. Hydrothermal treatment of the cured…
Abstract Die Korrosionsgeschwindigkeiten von 13/1‐CrNi‐, 13/4‐CrNi‐, 12/5/1‐CrNiMo‐ und 14/5/1‐CrNiMo‐Stahlguß werden in 3%iger NaCl‐Lösung, Meerwasser und in 2 n H 2 SO 4 mit bis zu 0,35 n NaCl auf elektrochemischem Wege durch Messung der Steigung der Stromdichte‐Potential‐Kurve beim Korrosionspotential sowie chemisc…
Investigating polymers irradiated under various conditions provides information on many of the processes occurring between initial energy absorption and final physical and chemical change. Among factors which can modify these reactions are the type of radiation, presence of oxygen and of additives, degree of crystalli…
Abstract The stratigraphy and age relationships of certain rock formations of Mysore are reviewed and the following points made out. (1) The Peninsular Gneisses as a whole are not intrusive into Dharwars. (2) The existing three fold classification of Dharwars has not taken into consideration the Dharwarian succession…
Abstract From the conversion–composition data of Gruber and Elias, the reactivity ratios of styrene (M 1 ) and methyl methacrylate (M 2 ) were calculated to be r 1 = 0.55 ± 0.02 and r 2 = 0.58 ± 0.06 at 90°C. The least‐squares method was then used on these and literature values at other temperatures to obtain the Arrh…
Abstract The radiation‐induced grafting to cellulose of styrene, methyl methacrylate, vinyl acetate, 2‐vinylpyridine, and 4‐vinylpyridine in methanol has been studied. All monomers exhibit appreciable grafting at room temperature in either vacuum or air for total doses up to 10 Mrad and at dose rates as high as 1.4 Mr…
Hall-effect measurements have been made on Te-doped GaAs crystals diffused with known amounts of 64Cu sufficient to convert the crystals to p-type. Energy levels are found above the valence band at 0.123±0.005 eV, 0.145±0.005 eV, 0.166±0.005 eV, 0.19±0.005 eV, and 0.43±0.01 eV. An analysis of the Hall data has been ma…
The effects are described of supersaturation, temperature, and relative motion of solution and crystal on the rate of sucrose crystal growth from aqueous solutions containing a wide range of impurities. The results are consistent with the conclusion, drawn from data in pure sucrose solution, that two main steps, neith…
The structure of hemimorphite, Zn 4 Si 2 O 7 (OH) 2 · H 2 O has been redetermined with three-dimensional data obtained both photographically and with a counter-diffractometer. R values of 7.1% and 4.0% were obtained for the two sets of data. There are no significant differences between the Si–O bond lengths (mean 1.62…
Abstract Acrylonitrile grafts readily to granular corn starch in aqueous slurry when initiated by hydrogen peroxide plus activator. Prime evidence for grafting lies in the ease of separating PAN from starch in high yield when the initiator is azobisisobutyronitrile rather than peroxide. Grafting efficiencies are deter…
Abstract Warp‐knitted velour fabrics of Dacron, nylon, polypropylene, and Rayon have been backed with Silastic to form a laminate. Prior to heat curing, the composite can be molded into many shapes and has been successfully used to line the luminal side of blood pumps and vascular grafts. Prosthetic heart valves are b…
The metabolism of collagen was studied by injecting proline-14C into rats and determining the specific activities and total activities of hydroxyproline-14C in the collagen fractions of the skin and in the urine, (a) When proline-14C was injected into thyroxine-treated rats, the total activity of hydroxyproline-l4C in…
Devitrification occurs near the cathode when reconstructed high‐silica glasses and fused quartz undergo electrolysis at 900°C. The crystalline phase is cristobalite and results from a concentration of alkali ions. Subsequent and more superficial crystallization around the alkali‐rich spot is caused by interaction of t…
Abstract The separation nozzle process is based on the partial spatial separation of components of different mass in an expanding supersonic jet stream. The process is of especial interest for the separation of uranium isotopes. Details of a systematic experimental determination of the most favorable operating conditi…
Methods of producing a fibre web for needle-punching on a laboratory machine are described: a parallel-laid card web was suitable for most purposes, though a cross-laid web was less anisotropic. Methods of operation and testing are described; the effects of specimen shape and size on tensile-test results were studied.…