Materials Literature
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Therecentobservation of orthorhombic α'‐Ca 2 Si0 4 (bredigite) at all temperatures between about 850° and 1450°C. leads to a rational interpretation of the polymorphism of this substance, which is very satisfactory from the crystal‐chemical point of view. The so‐called β phase, of as yet unknown, complex structure, ex…
ADVERTISEMENT RETURN TO ISSUEArticleNEXTThe Penetration of Cellulose Fibers.Alfred J. Stamm and Harold. TarkowCite this: J. Phys. Chem. 1950, 54, 6, 745–753Publication Date (Print):June 1, 1950Publication History Published online1 May 2002Published inissue 1 June 1950https://doi.org/10.1021/j150480a001RIGHTS & PERMISS…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Gelation of Sodium Silicate. Effect of Sulfuric Acid, Hydrochloric Acid, Ammonium Sulfate, and Sodium Aluminate.Reynold C. Merrill and Robert W. SpencerCite this: J. Phys. Chem. 1950, 54, 6, 806–812Publication Date (Print):June 1, 1950Publication History Published online…
The subject of this paper is treated mainly from the standpoint of cotton cellulose. The concept of crystallinity is discussed not simply in the narrow sense of degree of crystallinity but in the broader sense, which involves the whole fine structure of cellulose. With respect to crystallinity in the latter sense, the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPeriodate Oxidation of DextranAllene Jeanes and C. A. WilhamCite this: J. Am. Chem. Soc. 1950, 72, 6, 2655–2657Publication Date (Print):June 1, 1950Publication History Published online1 May 2002Published inissue 1 June 1950https://pubs.acs.org/doi/10.1021/ja01162a086https://…
Like the chemical properties of the elements, the work function φ is a periodic function of atomic number, as shown clearly by a new compilation of published data for 57 elements. The progressive rise and fall of work function values throughout the table of the elements appears to be sufficiently regular to permit app…
Models, largely based on the assumptions introduced by Peierls and Nabarro in dealing with a single dislocation, are used in calculations on three types of intercrystalline boundaries, namely, (I) a boundary due to a difference of atomic spacing, (II) a twist boundary, and (III) a symmetrical tilt boundary. With these…
Dilatometric and viscometric data on fractionated polystyrenes containing diethylbenzene end groups are presented over wide temperature ranges. The second-order transition temperature, viscosity-temperature coefficient, and specific volume all change rapidly with increasing molecular weight toward asymptotic limits wh…
Abstract In the first part of this paper, simple approximate methods have been developed for evaluating the electrical conductivity of films and wires of a size comparable with the mean free path of the conduction electrons. In the second part, a rigorous theory has been given of the electrical conductivity of a thin…
Evidence is presented for three new, light neptunium isotopes formed by deuteron bombardments of ${\mathrm{U}}^{233}$, ${\mathrm{U}}^{235}$, and ${\mathrm{U}}^{238}$. The isotope ${\mathrm{Np}}^{231}$ has a half-life of 50\ifmmode\pm\else\textpm\fi{}3 min. and emits alpha-particles of 6.28-Mev energy; the proportion o…
When a crystal of magnetite has been cooled through the low temperature transition (near -164\ifmmode^\circ\else\textdegree\fi{}C) in a demagnetized state, the magnetization undergoes a large and abrupt increase in the three principal crystallographic directions [100], [110], and [111] upon warming. The behavior of th…
The microwave resonance absorption technique, at both 1.25 and 3.3 cm wave-lengths, was used to study the ferromagnetic crystalline anisotropy characteristics and $g$-factor of magnetite ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$. The experiments were performed on single crystals, both synthetic and natural, from room temp…
An objective method for determining fiber irregularities is suggested wherein it is recog nized that there are many instances of crimpiness which cannot be defined in terms of frequency and amplitude measurements. An attempt was made to arrive at a simple correlation between roving diameters and single-fiber propertie…
Published differential thermal‐analysis curves for aragonite have not shown the transition to calcite near 450 °C. This inversion is clearly seen in curves presented for six samples of aragonite, and the transition is confirmed by X‐ray diffraction patterns.
The volatility of plutonium dioxide has been measured in the temperature range 1320°C to 1790°C by a modification of the Knudsen effusion method. The plutonium dioxide was heated in vacuum in a tantalum oven. Under these conditions the dioxide was reduced to a lower oxide, or oxides, which maintained a constant reprod…
(1950). 9—THE RELATION BETWEEN FIBRE AND YARN FLEXURAL RIGIDITY IN CONTINUOUS FILAMENT VISCOSE YARNS. Journal of the Textile Institute Transactions: Vol. 41, No. 4, pp. T159-T172.
A method is described by which the surface tension of surfaces occurring in the systems copper-hydrogen or argon and copper-lead-hydrogen or argon is determined. At temperatures round 850° C the surface tension between copper grains is 640 dyne/cm. and between copper and the equilibrium lead-copper liquid phase 340 dy…
The temperature dependence of F-absorption bands has been theoretically studied. It has been concluded that the main cause of the shift of the absorption peak is the thermal expansion of the lattice. As to the half-breadth of the band we calculated its temperature dependence by using the Einstein's model of lattice vi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory, Scope, and Methods of RecrystallizationR. S. TipsonCite this: Anal. Chem. 1950, 22, 5, 628–636Publication Date (Print):May 1, 1950Publication History Published online1 May 2002Published inissue 1 May 1950https://pubs.acs.org/doi/10.1021/ac60041a002https://doi.org/10.…
The importance of crimp in natural wools is discussed. Wear and coverage of crimped vs. uncrimped materials are demonstrated. A method of crimping wool artificially is shown and production equipment is discussed schematically. Theoretical expressions are developed for stress-concentration effects and are compared with…