Materials Literature
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An apparatus is described to measure volumetrically the amount of gas adsorbed by a catalyst at constant pressure and at exposure times as short as 0.1 min. The volumes of oxygen adsorbed by a technical silver catalyst at pressures of 200, 400, and 700 mm. and in the temperature range of 180° to 300°C. have been measu…
During neutron irradiation at 100°c alpha uranium creeps slowly (e.g. 10−−7 per hour) under external stresses of order of one-hundredth of the normal yield stress of the metal at that temperature. This effect is predicted as a consequence of the phenomenon of “radiation-growth” which occurs in uranium, and is then con…
The magnetization of some rare-earth orthoferrites and related compounds, and of some iron-group cyanides, has been investigated at temperatures between room temperature and 1.3\ifmmode^\circ\else\textdegree\fi{}K. Some are ferromagnetic, some antiferromagnetic, and some paramagnetic following the Curie-Weiss law.The…
Journal Article Clays and Clay Minerals Get access Clays and Clay Minerals, Edited byAdaSwinepord, Norman Plummer, Proceedings of the Second National Conference on Clays and Clay Minerals. National Academy of Sciences-National Research Council, Washington, D. C, 1954. viii pp. Illus., index, bibl. R A Heindl R A Heind…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Plutonium-Hydrogen System. II. Solid Solution of Hydrogen in Plutonium Dihydride1Robert N. R. Mulford and Gladys E. SturdyCite this: J. Am. Chem. Soc. 1956, 78, 16, 3897–3901Publication Date (Print):August 1, 1956Publication History Published online1 May 2002Published in…
The' linear t he rm a l ex pa nsion of fOlll samples of T eflo n was de termined . The' res ults for an neil. lecl T eflon m'e indi cated in a plot of t he ex pa nsion vel s us te m perature and in iI. table li st in g t he average coeffi cLCnts of lincar expa ns io n from -J 90 to + 300 C. The eff ect of internal r e…
Abstract The tear properties of natural rubber and GR‐S vulcanizates containing carbon black are compared with those of gum vulcanizates, using a method developed in a previous paper. The distinctive features in the tear behavior of the filed vulcanizates are noted and discussed. The results indicate that there are tw…
A phenomenological theory of the time dependence of mechanical breakdown phenomena is presented which is applicable to creep failure of oriented polymeric filaments under tensile stresses. In using the theory, one makes assumptions about the distribution of breaking times in ensembles of filaments which are bearing co…
Abstract Increasing the degree of crystallization of unoriented 66 or 610 nylon increases the stiffness, yield point, tensile strength, and hardness, but reduces the impact strength, particularly in the high crystallinity range. The impact strength was increased by increasing the molecular weight, but the other proper…
Abstract The bands due to stretching of OH groups of all four crystalline modifications of cellulose have been measured using a deuteration technique which enables crystalline regions to be studied independently of amorphous regions. Cellulose III prepared from cellulose I (III I ) was found to be different from cellu…
The reduction in the ionization loss of charged particles due to the polarization of the medium has been calculated using the mean excitation potentials recently determined by Caldwell. Values of the coefficients of an approximate analytic expression for the density effect correction have been obtained for a number of…
The propagation of short mechanical pulses along rods of three polymers, polythene, polystyrene and polymethylmethacrylate, has been investigated experimentally. The pulses were produced by the detonation of small quantities of explosive at one end of a rod and a condenser microphone was employed to record the displac…
The switching time ts and the switching current imax have been measured as a function of applied field E and of the size of the sample. It has been observed that the ``activation field'' α for the nucleation of new domains is inversely proportional to the thickness of the sample. This behavior can be explained by assu…
Descemet's membrane, previously thought to be "structureless," has been found to be characterized by a fine structure of great regularity. Sections perpendicular to the plane of the membrane surface appeared to be cross-striated, with narrow dark bands separated by wide light bands traversed by fine filaments. Tangent…
Activation cross sections for about thirty products of high-energy proton-induced disintegration of ${\mathrm{U}}^{238}$ and ${\mathrm{Th}}^{232}$ have been measured by the radiochemical method. These products range from polonium ($Z=84$) to neptunium ($Z=93$). The energy dependence of some of these cross sections has…
Abstract Results of earlier investigations of dynamic yield phenomena are reviewed. Experiments are described in which a mild steel specimen is subjected a to compressive impact load causing yield in 25 to 30μs. Stress-time curves are obtained and analyzed in terms of wave propagation, and a dynamic stress-strain rela…
Abstract The oxidation of electrolytically polished aluminium single-crystal surfaces, presenting (100), (110) and (111) faces, has been studied in dry oxygen at 20° C and 760 mm Hg and in 80% saturated oxygen at 25° C and 760 mm Hg; three methods (anodic polarization, electron diffraction and capacity) have been empl…
Abstract Thin crystals of copper and platinum phthalocyanine have been studied in the transmission electron microscope. The (20T) planes of the crystal lattice have been resolved and the distance between them (12.0 + 0.2 A) is in close agreement with the X-ray value of 11.94 A. Imperfections in the lattice have been d…
Abstract In dealing with this problem, the cause of stress must be considered, and whether the stress remains constant, decreases, or increases as yield or creep occurs as a result of high stress. A qualitative analysis of the stress due to a maintained temperature differential in a flat bar is given for both free and…
Fluorine and iodine compounds, both organic and inorganic, were tested as flame retardants for cotton. Comparison with bromine and chlorine compounds showed that the effectiveness of the halogens, on an equal weight basis, increases in the order. fluorine, chlorine, bromine, iodine, with the last two about equally eff…