Materials Literature
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One of the unanswered questions in the study of fatigue is how cracks nucleate at stresses far below the static fracture strength. Previous theories show possible qualitative mechanisms that may operate in a crystal at room and low temperatures but none provides a quantitiative theory of this phenomenon. We show here…
The existing literature on UAl2-Al dispersions is surveyed and a comparison with similar data for UAl3-Al dispersions is attempted. The experimental work included the preparation of a practically single-phase UAl2 compound by induction-melting and its grinding to a predetermined particle size. The blending of UAl2 and…
It is demonstrated by means of freely corroding total immersion tests and anodic and cathodic polarization experiments, that small amounts of arsenic in solid solution in α-brass, effectively prevent dezincification even in the most agressive media. On the other hand, the addition of relatively large amounts of arseni…
The thermal diffusivity of the ThO2-UO2 system in solid solution was measured by laser pulse method at temperatures ranging from 20° to 500°C. Reproducibility of the data was confirmed to be within 3%. The compositions of the samples were ThO2, ThO2-1%UO2, ThO2-5%UO2 and ThO2-10%UO2. The thermal conductivity was calcu…
The effects of Y and Bi substitutions on spin reorientation in ErFeO3 have been studied through optical absorption and magnetization measurements. Below the reorientation temperature Tr, optical absorption lines from low-lying Er3+ levels show splittings of several cm−1. The splittings decrease above Tr. With addition…
The mature akinete coat of a Cylindrospermum species contains laminar layers, not present in immature akinetes, and a thickened intermediate layer.
The effect of micrestructure on the glass temperature Tg of poly (α-methyl styrene) has been investigated. It has been observed that Tg increases as the syndiotacticity of the molecule increases-thus Tg = 446 ± 2°K for polymer with 67% syndiotactic placements, while a value of Tg = 453 ± 2°K is found for a sample with…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterpretation of the kinetics of thermogravimetric analysisEli S. Freeman and Benjamin CarrollCite this: J. Phys. Chem. 1969, 73, 3, 751–752Publication Date (Print):March 1, 1969Publication History Published online1 May 2002Published inissue 1 March 1969https://pubs.acs.org…
The compound Gd2CoMnO6 crystallizes with the orthorhombic perovskite structure and is isomorphous with GdFeO3. A crystal structure refinement shows that the Mn3+-O2−-Mn3+ bond angles are ∼ 145° and that the distortion from cubic symmetry is considerable. A spontaneous moment of 5 e.m.u./g develops below 115°K due to t…
An electron microscope investigation has been made of the decomposition of ⅓〈1120〉 slip dislocations when they penetrate {1012} deformation twin boundaries in polycrystalline zinc specimens. The results show that the decomposition can result in the formation of stacking faults in deformation twins and that these fault…
A processing programme is outlined in which yarn pre-twist, applied air-pressure, and supply-yarn overfeed are systematically varied in the air-jet bulking process to investigate their effects on air-textured nylon 6.6 continuous-filament yarns. Optical magnification of the air-textured yarns enables the average loop…
Summary It is pointed out with the help of the Independent Domain Theory, that a fraction of the pore‐water constituting a volume Δ V is contained in pores not common to both the wetting and drying states and that this volume in a wetting state is contained in pores whose draining radii are greater than those of the p…
Single crystals of α-manganese were grown by the distillation method. These weigh about 300 mg. Crystallographic parameters which define the positions of manganese atoms have been determined by x-ray diffraction. The magnetic structure was determined with better accuracy than that determined by the powder method. It i…
Polyethylene single crystals from dilute solutions usually have a density ρ which is less than that of the ideal crystal lattice (ρc = 1.000 g/cm3). This density defect can be formally assigned to an “amorphous” component (1-α) = (ρc-ρ)/(ρc-ρa) and may be caused by vacancies in the crystal lattice and/or by the surfac…
Abstract The density, congealing point, and hardness were considered in relation to crystallinity, determined by an infra‐red spectrometric method, of a series of waxes which are fractions from crude Fischer–Tropsch wax. Values ranging between 65 and 93, expressed as molecular percentages of crystalline material prese…
Abstract An analog computer‐polymerizer system is described which polts continually the rate of polymerization in percent per hour and the total percent conversion. Computer components and their functions are briefly described and the polymerization vessel with its control instruments are shown. Methods of calibration…
The optimum conditions are discussed for generating channelling patterns (i.e. orientation dependent lines and bands of contrast) in the scanning electron microscope. From considerations of the electron optics it is shown that patterns of highest angular resolution may be obtained by establishing a compromise between…
Cold-rolled-(110)[001]-oriented single crystals of 3% silicon iron containing AlN in solution develop a doublet {111} 〈110〉−oriented primary recrystallization texture consisting of grains with diameter of 0.5 to 1 mm after anneal at 550°C for 40 h followed by anneal at 1200°C. At the first anneal, very fine needle-lik…
This paper invokes the combined action of the crystalline field and exchange in an attempt to explain theoretically why the susceptibility χ of cubic Eu2O3 is found by experimenters to be 30% higher than that for the free Eu3+ ion at temperatures below 50°K. The crystalline field is known approximately from optical st…
A vibrating-coil magnetometer used in conjunction with a helium-gas pressure-generating system has proved to be a versatile new means of studying the effects of hydrostatic pressure on magnetic properties. The sensitivity of this system permits the measurement of paramagnetic susceptibilities on powder samples of the…