Materials Literature
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As the permeability of rubber-like substances to gases stands in relation to the solubility and rate of diffusion of the gases in those materials, these individual values should be known. The permeability of a membrane was measured manometrically and the diffusivity was derived from the time-lag of the permeation. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh dielectric constant ceramicsA. von Hippel, R. G. Breckenridge, F. G. Chesley, and Laszlo TiszaCite this: Ind. Eng. Chem. 1946, 38, 11, 1097–1109Publication Date (Print):November 1, 1946Publication History Published online1 May 2002Published inissue 1 November 1946https:…
Values of the carbon-nitrogen single-bond distance in various compounds are of special interest because of the occurrence of this bond in amino acids, proteins and related substances. Numerous electron diffraction studies of gas molecules have yielded values of about 1.47 Å, which are consistent with the usual table o…
The elastic, piezoelectric, and dielectric constants of sodium chlorate (NaCl${\mathrm{O}}_{3}$) and sodium bromate (NaBr${\mathrm{O}}_{3}$) have been measured over a wide temperature range. The value of the piezoelectric constant at room temperature is somewhat larger than that found by Pockels. The value of the Pois…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction between Ferric Oxide and Barium Carbonate in the Solid Phase. Identification of Phases by X-Ray Diffraction1Michael Erchak Jr., I. Fankuchen, and Roland WardCite this: J. Am. Chem. Soc. 1946, 68, 10, 2085–2093Publication Date (Print):October 1, 1946Publication Histo…
A bstract The dielectric constants and dielectric losses of 104 glasses of a wide range of compositions have been measured at 10‐cm. and 3‐cm. wave lengths by the resonating cavity method (3000 and 10,000 megacycles, respectively). By correlating the power‐factor data with the compositions of these glasses, the author…
Abstract Having previously advocated the use of height to define maturity as a basis for legal control of cutting in young stands, the author now develops the use of height as a factor in the measurement and regulation of growing stock. An equation is offered which may prove to have value in defining upper and lower l…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolytetrafluoroethyleneW. E. Hanford and R. M. JoyceCite this: J. Am. Chem. Soc. 1946, 68, 10, 2082–2085Publication Date (Print):October 1, 1946Publication History Published online1 May 2002Published inissue 1 October 1946https://pubs.acs.org/doi/10.1021/ja01214a062https://d…
Failure of adhesive bonds is attributed to boundary stress concentrations. An analysis of the causes of internal-stress concentrations in rigid adhesive layers leads to the conclusion that stress concentrations can be eliminated in many cases by matching the coefficients of thermal expansion of the component parts. A…
Abstract On the basis of the theory discussed in the preceding parts of this series, a method has been devised for determining the temperature coefficient and hence the activation energy of the process responsible for starting the chains in the thermal reaction between hydrogen and oxygen. The results are consistent w…
Abstract When rubber goods are exposed to the agencies which constitute “weather”, they undergo profound changes. The rubber may lose elasticity, it may split or crack, or the surface may take on a crinkled appearance in a wide variety of designs. Figure 1 shows a small selection of such weathered rubbers. The course…
Comparative measurements at large and small distances have been made on the pressure wave from a small underwater explosion. It is shown that: (1) there is a small departure from the $\frac{1}{r}$ law for the peak pressure, (2) there is no detectable change in shape or "spreading" of the pressure wave with propagation…
Abstract The investigation was undertaken in an attempt to establish the fundamental connections between the physical properties of a typical vulcanized rubberlike polymer and its chemical structure. The structural variables to be considered are the molecular weight of the “primary molecules” entering the vulcanizate,…
The transition in the value of the initial magnetic permeability of iron and nickel from the d.c. permeability \ensuremath{\sim}100 to the infra-red permeability \ensuremath{\sim}1 is known to occur principally in the microwave frequency range. An explanation of the experimental facts is proposed by considering the eq…
A possible structure for kaolinite was first put forward by Pauling (1930) in a paper dealing generally with the structures of layer-type minerals, chlorites, micas, &c. He suggested that the structure consisted of a sheet of Si–O tetrahedra arranged in a hexagonal network with a superposed sheet of Al–(O,OH) octa…
Abstract Squalene containing six isoprene units is more free of end‐group effects and less limited in the range of space‐distributional contortions of its carbon chain than mono‐ and diolefins. Hence it is more comparable with rubber than the latter group where matters of chemical reactivity are concerned. Nevertheles…
A bstract In the course of an investigation that involved a study of pyrochemical reactions, it was necessary to develop a refractory that could be used satisfactorily at temperatures in the range of 1800° to 2200°C. It was found that calcined magnesia (96%, MgO) or electrically fused magnesia (98% MgO) could be bonde…
This paper presents measurements of the forces required to drive a punch into plates of several grades of steel as a function of the distance of penetration, the entire punching operation being conducted in a fluid medium subjected to hydrostatic pressures up to 30,000 kg/cm2. Qualitatively, the effects are similar to…
Abstract The kinetics of the initial stages of the thermal oxidation of ethyl linoleate (by molecular oxygen) have been investigated in the temperature range 35—75° C. From consideration of chemical and kinetic evidence the reaction mechanism has been established: oxidation chains are initiated by thermal decompositio…
1. The natural history in culture of the species of Nitzschia originally isolated from the sea by Allen & Nelson (1910) and grown at Plymouth and elsewhere ever since has been studied. It is shown that three main types of cell exist: normal with two arms (rostra), triradiate with three arms and ovals with none. Bo…