Materials Literature
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Summary A hydrated barium pyrochlore (pandaite) has been found at Mrima Hill (Kenya) in a residuum consisting mainly of goethite/limonite and gorceixite. The pandaite occurs as pale yellow or white octahedral crystals, which have a micro-crystalline interior. It is isotropic, the refractive index varies from 2·07 to 2…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure Property Relationships in Polyurethane Elastomers Prepared by One-Step ReactionK. W. Rausch Jr. and A. A. R. SayighCite this: Ind. Eng. Chem. Prod. Res. Dev. 1965, 4, 2, 92–98Publication Date (Print):June 1, 1965Publication History Published online1 May 2002Publish…
The room temperature luminescence spectra of the monoterpyridyl chelates of trivalent samarium, dysprosium and thulium have been studied in solid state by exciting with monochromatic radiation of 3200 Å. The spectra of these chelates show intra f → f fluorescent transitions of the chelated rare earth ions as well as t…
Abstract The effect of ozone on the growth of cuts in rubber strips subjected to repeated tensile deformations has been investigated. At tearing energies below a critical value ozone accounts for all the cut growth, and in this region the rate of growth also occurs due to mechanico‐oxidative rupture, the rate of this…
Abstract Thirteen dimensional parameters are suggested as necessary to describe a sedimentary particle, and a range of form indices is derived from these. The behavior of a particle depends on each form index which defines the particle and a general correlation can only be obtained by examining the performance versus…
The utility of ferrite cores which have the Curie temperature in the vicinity of the room temperature and suddenly change the permeability vs. temperature characteristic near the Curie temperature is described in this paper. Using the characteristics of these ferrite cores, the author made an overcurrent relay and a l…
SUMMARY The following marine chrysomonads, originally described by Carter, are redescribed: Pseudopedinella pyriforme, Ochromonas oblonga, and Pyrmnesium parvum. Parachrysiclalis n.g. is set up for P. estuariale, with a flattened body and 2 equal flagella inserted in the middle of one side. Redescribed Xanthophy‐cean…
Abstract The ordinary methods for obtaining a rapid estimate of the useful life of a plastic, extrapolations from tests conducted at higher temperatures or at lower stabilizer concentrations than those of actual use, lead to serious errors in estimating the useful life of some stabilized polypropylene compositions. Tw…
Plate-like crystals of BaTio 3 , 20 to 140 µ thick, were treated thermally in order to create conditions for the establishment of an equilibruium 180° domain structure corresponding to minimum electrostatic and wall energy. It has been found that with slow cooling of the crystals from the paraelectric phase in a mediu…
Abstract Model substances were prepared of a polyurethane rubber filled with different amounts of various fractions of sodium chloride. Eight filler fractions were used of sizes in the range of 1–480 μm. The amount of filler was varied between 0 and 50 vol.‐%. An experimental method is described by which thermal expan…
Electron optical technique has been used to study the mechanism of the polymorphic transformation in KAlSi3O8. This transition involves a reduction in symmetry from monoclinic (C2/m) to triclinic (CI) with falling temperature and is associated with ordering of the aluminium–silicon distribution on tetrahedrally coordi…
Measurements have been made between 2 and 30°K of the linear thermal expansion of single crystals of Mg, Zn and Cd, both parallel (⌋) and normal (Ι) to the hexad axis. Values have also been obtained at liquid oxygen temperatures and at room temperature which agree with previous data. (i) For Mg, the linear coefficient…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetal Acetylacetonate Catalyzed Epoxidation of Olefins with t-Butyl HydroperoxideNorman IndictorCite this: J. Org. Chem. 1965, 30, 6, 2074–2075Publication Date (Print):June 1, 1965Publication History Published online1 May 2002Published inissue 1 June 1965https://pubs.acs.org…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Crystal Structure and Molecular Stereochemistry of Methoxyiron (III) Mesoporphyrin-IX Dimethyl Ester1J. L. Hoard, M. J. Hamor, T. A. Hamor, and W. S. CaugheyCite this: J. Am. Chem. Soc. 1965, 87, 11, 2312–2319Publication Date (Print):June 1, 1965Publication History Publi…
An unusual form of kaolin mineral filling cracks in weathered prophyritic granite in the county of Piedade, Sao Paulo, Brazil, consists of visibly fibrous material which, in the electron microscope, appears as thin tubular fibers of considerable length; platy particles are almost entirely absent. X-ray rotation diagra…
Abstract The graft copolymerization of acrylate monomers, methyl, ethyl, n ‐propyl, and n ‐ or isobutyl, in cotton fabrics was carried out in the aqueous emulsion system by the ceric ion method. The rate of grafting decreases with increasing length of the ester group. The maximum improvement of dry crease recovery, th…
A simple apparatus and special techniques are described which have been used to purify and to grow single crystals of KCl and KBr. The measured inpurity content of such crystals is lower than that of commonly used, commercially available crystals by a large factor. Residual impurities have fractional concentrations, i…
In the system alkali-oxide-transuranium-oxide-oxygen, ternary oxides containing hexavalent transuranium elements were prepared by reactions in the solid state. Depending on reaction conditions, the following compounds were obtained: Na2Np2O7, α-Na2NpO4, Li4XO5(X Np, Pu, Am), α-Na4XO5(X U, Np, Pu, Am), β-Na4XO5(X …
Abstract The possibility is considered that clay minerals can influence the formation of some kinds of dolomite, either by supplying magnesium ions or serving as membranes that control ionic migration.
Expressions may be derived for the thermal expansion coefficient of polycrystalline graphite in terms of the single-crystal coefficients and the preferred orientation of the sample. Thermal expansion and preferred orientation measurements were performed on pyrolytic, molded, hot-worked, extruded-rod, and extruded-tube…