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The principles of the conversion of heat energy directly into electrical energy by use of a ferroelectric material heat cycled in the neighborhood of its Curie point are described. A simplified expression for the energy conversion efficiency is derived, and reasonable values for appropriate parameters are used to obta…
Measurements of the packing of spherical particles poured into a cylindrical container show that the intensity of deposition, the height of drop and the elasticity of the particle material influence the packing equally. Minor departures from perfect sphericity tend to mask the influence of elasticity. Optimum packing…
Discrepant interpretations regarding the frequency of the C=S stretching mode are reviewed and assignments of frequencies for the vibrational modes of the xanthate group, [Formula: see text] are presented.A band at 1020–1070 cm −1 is assigned to the C=S stretching mode. Bands at 1200 cm −1 and 1110–1140 cm −1 are ascr…
Abstract A study of the thermal conductivity of some amorphous and partially crystalline polymers as a function of temperature (0–100°C.) is described. Experiments have been carried out, with the use of a thermal conductivity cell with cylindrical geometry, on polyethylene, polytetrafluoroethylene, polystyrene, polyhe…
In this study the effect of additions of 0.0015 to 0.0030 mole fraction of rare‐earth oxides on the d.‐c. resistivity of sintered barium titanate was investigated. The substitution may be represented by ( X 2 O 3 ) M (BaTiO 3 ) 1‐M where X is the rare earth. The rare earths samarium, gadolinium, and holmium were intro…
A spin-Hamiltonian approach to the theory of spin-lattice relaxation in paramagnetic salts is developed in which the orbit-lattice interaction is treated as a perturbation connecting states of the overall spin-Hamiltonian. The approach is much simpler than previous treatments where the spin-orbit and Zeeman effects we…
Abstract The crosslinking efficiencies of several curing agents have been determined from swelling measurements. The results indicate that dicumyl peroxide is a quantitative crosslinking agent for natural rubber, as was previously found to be true of dimethyloctadiene. As one molecule of dicumyl peroxide is able to fo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhysical Chemistry of Surfaces.Herman E. Ries Jr.Cite this: J. Am. Chem. Soc. 1961, 83, 8, 2028–2029Publication Date (Print):April 1, 1961Publication History Published online1 May 2002Published inissue 1 April 1961https://pubs.acs.org/doi/10.1021/ja01469a073https://doi.org/1…
Long- and short-range interactions of dislocations and the likely result of dislocation intersections in fcc lattices are assessed. Of the 24 possible secondary glide systems which could interact with a primary system, 12 promote work hardening by providing strong blocks to primary glide propagation, while 12 provide…
Calculations show that, under concentrated load, ratio of pressures and deflections along beam are constant if beam has infinite length; when analysis of beams of infinite length, resting on elastic-isotropic half-space, is based on coefficient k of subgrade, reaction bending moments are overestimated, contact pressur…
Abstract Expressions are derived from free volume considerations which predict the concentration dependence of viscosity and glass temperature for polymer‐diluent systems. Experimental data for several systems were examined and general agreement with theory was found over broad ranges of concentration. Particular emph…
Abstract Wholly aromatic polybenzimidazoles were synthesized from aromatic tetraamines and difunctional aromatic acids and characterized as new thermally stable polymers. The melt polycondensation of aromatic tetraamines and the diphenyl esters of aromatic dicarboxylic acids was developed as a general procedure of wid…
Abstract The solubility constants for thirteen permanent gases were measured within the temperature range 5–55°C. in a linear and a branched polyethylene, hydrogenated polybutadiene, and natural rubber. Equilibrium and time lag solubility determinations were made, the latter being indirectly obtained as the ratio of t…
Abstract Diffusion and permeability constants for twelve permanent gases have been measured in a linear and a branched polyethylene, hydrogenated polybutadiene, and natural rubber over the temperature range 5–55°C. The Barrer time lag apparatus has been used in these determinations. For all gas–polymer pairs investiga…
The thermal conductivities of single-crystal bars of several ferrites have been measured over the temperature range 1.4\ifmmode^\circ\else\textdegree\fi{} to 25\ifmmode^\circ\else\textdegree\fi{}K in both zero external magnetic field and in a field of about 9.4 kilo-oersteds. For each speciment the zero-field conducti…
Results are reported of a study of the contribution of spin or exchange polarization to the magnetic interaction of a rare earth ion with its neighbors and with its own conduction electrons. The rare earth ions carry a paired electron spin density which is negative in their outer reaches and these ions may even appear…
Sodium-ion vacancies are introduced into sodium chloride crystals by the addition of the following divalent cation impurities: ${\mathrm{Mg}}^{++}$, ${\mathrm{Mn}}^{++}$, ${\mathrm{Ca}}^{++}$, ${\mathrm{Zn}}^{++}$, ${\mathrm{Cd}}^{++}$, and ${\mathrm{Sr}}^{++}$. Below 150\ifmmode^\circ\else\textdegree\fi{}C, the virtu…
In an anisotropic ferromagnet the Curie temperature is a function of the direction of the magnetization. The Curie temperature is high in easy directions, and can drop quite low in harder directions for large ratio of anisotropy to exchange energy. Magnetization curves as a function of temperature also depend upon the…
Previous calculations of the instability threshold have been based on a plane-wave analysis which is strictly applicable only in an infinite medium. This paper describes a more rigorous theory in which the boundary conditions at the surface of the sample are taken into account. The refined theory admits instabilities…
Solid solutions based on sodium niobate with limited amounts of lead and zirconium or lead and titanium solute ions have been investigated with respect to their dielectric constant versus temperature at 1 kc. per second from −175° to 300°C. Lead zirconate additions to sodium niobate up to 15 mole % cause an increase i…