La perforation èlectrique dans l’exploitation des carrières
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Breakage of Carbon-Rubber Networks by Applied Stress
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBreakage of Carbon-Rubber Networks by Applied StressA. F. Blanchard and D. ParkinsonCite this: Ind. Eng. Chem. 1952, 44, 4, 799–812Publication Date (Print):April 1, 1952Publication History Published online1 May 2002Published inissue 1 April 1952https://pubs.acs.org/doi/10.10…
XXXVIII. Twin formation, in cadmium
Summary Experiments on the formation of twins in single crystal wires of cadmium under tension demonstrate the essentially discontinuous nature of the process of twin growth, and produce evidence in favour of a critical resolved shear stress law for twinning. Twinning can contribute to creep at room temperature but no…
Dielectric Constant in Perovskite Type Crystals
Slater's theory of the dielectric constant in BaTi${\mathrm{O}}_{3}$ has been extended by treating the ionic polarizability quantum mechanically instead of classically. This leads to an expression for the dielectric constant which is good at all temperatures and shows a deviation from the Curie-Weiss law at low temper…
The reaction between carbon monoxide and oxygen on cuprous oxide at room temperature
Abstract The catalytic reaction has been studied on a granular surface of the metal coated with cuprous oxide. The nature of the adsorbed species in the stationary state of the reaction has been investigated by measurements of heats of adsorption and by B. E. T. measurements. The adsorption characteristics of cuprous…
The thermal decomposition of lithium aluminium hydride
Abstract Lithium aluminium hydride on heating decomposes in three stages: (a) an initial surface reaction during the induction period, followed by (b) an interface reaction giving an S-shaped pressure against time curve, corresponding to LiAlH4 → LiAlH2 + H2, and (c) a slow process during which a third hydrogen atom i…
The Viscosity and Rigidity of Gelatin in Concentrated Aqueous Systems. I. Viscosity
The viscosity of gelatin solutions at concentrations between 100 and 500 g./l. has been studied as a function of pH, ionic strength, and temperature. In these concentrated systems the predominant factor determining the viscosity appeared to be Coulombic forces between ionized groups on adjacent chains.
Growth and crystallography of deformation of β-phase uranium single crystals
Single crystals of the tetragonal fl-phase of uranium were grown in material containing small amounts of chromium by a 7 --> fl phase-transformation method. These crystals could be retained in a metastable condition for long periods following their quenching from normal fl-phase temperatures into water at room tempera…
Mechanics of Elastic Performance of Textile Materials
Graphs have been developed to simplify the study of fabric geometry. A simultaneous plot of the mathematical relations developed by Peirce aids in visualizing dimensional changes in fabrics and gives accurate values of the various parameters without lengthy calculations and interpolations from tables. The use of the g…
On the Theory of the Dielectric, Piezoelectric, and Elastic Properties of NH4H2PO4
The theory of KH2PO4 developed by Yomosa and the present writer can be applied to the upper phase of NH4H2PO4 without any alteration. All the experimental data can be represented by the formulas of this theory. It is shown that this theory has a more general character than it appears as based upon Slater's model of KH…
The Polymorphism of MgSiO3and Solid-State Equilibria in the System MgsiO3-CaMgSi2O6
The investigation is divided into two parts: the first is concerned primarily with stability relations among the various crystalline phases of $$MgSiO_{3}$$. Contrary to results given in previous published investigations, experimental evidence favors the stability of rhombic enstatite and protoenstatite. Clinoenstatit…
A Review: Chemical Treatment to Mitigate Corrosion
A review of surface active and ionic type corrosion inhibitors, methods of neutralization and buffering, removal of corrosive agents, self-repairing coatings and bactericides are discussed. Anodic and cathodic agents are considered at length and the various factors incident to the use of these types of inhibitors desc…
Copolymerization theory of the vulcanization of rubber. VI. Hydrogen sulfide effects and some self‐limiting features
Abstract Vulcanization with sulfur is ascribed to the formation of sulfur radicals which are believed to copolymerize with the rubber molecule double bonds. Hydrogen sulfide is proposed as necessary for chain initiation but when formed in sufficient amounts serves as a chain terminator. This is believed to lead to num…
The Principles of Textile Finishing
The historical relationship between the science and the technique of textile finishing is illustrated herein by a description of the principles of indigo dyeing. This ingenious technique was developed thousands of years ago, but it has been understood only recently. The rapid progress of polymer and colloid science ha…
Physical Structure and Magnetic Anisotropy of Alnico 5. Part I
It is concluded from electron metallographic results that the high coercive force and anisotropy of Alnico 5 are caused by a very finely divided precipitate produced by the permanent magnet heat treatment. This precipitate is a transition structure rich in cobalt and is face-centered cubic with a0 = 10A and appears as…
Shape and Movement of Mesenchyme Cells as Functions of the Physical Structure of the Medium
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
A STUDY OF FIXATION FOR ELECTRON MICROSCOPY
Osmium tetroxide fixation of tissue blocks, as usually effected, is preceded by an acidification of the tissue. This acidification is probably responsible for morphological alterations which are notably disturbing in electron microscopy. The acidification and the resulting morphological alterations cannot be prevented…
Lattice Parameters, Coefficients of Thermal Expansion, and Atomic Weights of Purest Silicon and Germanium
Lattice parameter determinations of 99.97 percent pure silicon (containing 0.03 percent carbon) were carried out using the asymmetric method, a 64-mm precision camera in a thermostat at constant temperatures (10, 20, 30, 40, and 50°C). The powder mounts, about 0.12-mm in diameter, were translated and rotated during th…
Adsorption of Water Vapor by Montmorillonite. II. Effect of Exchangeable Ions and Lattice Swelling as Measured by X-Ray Diffraction
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdsorption of Water Vapor by Montmorillonite. II. Effect of Exchangeable Ions and Lattice Swelling as Measured by X-Ray DiffractionR. W. Mooney, A. G. Keenan, and L. A. WoodCite this: J. Am. Chem. Soc. 1952, 74, 6, 1371–1374Publication Date (Print):March 1, 1952Publication H…
Intrinsic Magnetization in Alloys
The intrinsic magnetization of alloys among the iron transition group of metals has been explained using a Heitler-London model for the $3d$ electrons. The magnetic moment associated with each atom is determined by the principle of maximum spin and the sign of the interaction between neighboring pairs from the overlap…