Materials Literature
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Drawn and undrawn nylon 66 filaments were exposed to oxygenated aqueous systems, and the extent of chemical degradation was studied as a function of time. Degradation was estimated by measuring the changes in both chemical and physical properties. At the same time, oxygen absorption measurements were made and these we…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolyoxamides. II. Polymerization of Cyclic DiamidesO. Vogl and A. C. KnightCite this: Macromolecules 1968, 1, 4, 315–318Publication Date (Print):July 1, 1968Publication History Published online1 May 2002Published inissue 1 July 1968https://pubs.acs.org/doi/10.1021/ma60004a00…
Abstract Temperature dependence of dielectric loss, mechancial loss, and dynamic modulus were measured to study polymer blending. Results were as follows: Dielectric loss and dynamic modulus of NR—BR blends showed two peaks corresponding to NR and BR, indicating that the blends were microheterogeneous. A single, broad…
A literature survey on thermal stresses during welding and buckling after welding is described. From the analyses found, a computer program was developed to calculate thermal stresses and resulting residual stresses due to a moving heat source. This program is included in the appendix. Studies at Marshall Space Flight…
The infrared absorption spectra of the four zinc halides have been investigated by the low-temperature matrix-isolation technique. The spectral range 800–35 cm−1 has been covered. Four absorption regions have been observed in all cases. The highest energy region is structured and represents the antisymmetric stretchin…
The input admittance of a circular waveguide opening onto an infinite flange with a homogeneous lossy dielectric coating is derived using integral transforms and assuming the dominant TE11mode as the trial field at the aperture. Admittance calculations for low-loss dielectric sheets of various thicknesses are given an…
The structure of aluminum chloride hexahydrate, A1C13.6H20, has been studied with X-ray and neutron diffraction techniques. Precise values for the dimensions of the hexagonal unit cell have been obtained: a= 11-827 + 0.006, c= 11.895 + 0.003/~. Single-crystal X-ray data have been used to confirm the space group, R3c,…
The transition region analysis of an abrupt heterojunction is extended to include the effects of mobile carriers‘ charge in the space charge regions. Deviations from the depletion model are obtained when the wide band-gap semiconductor is heavier-doped-This is due to a non-negligible potential drop across the narrow b…
Measurements have been made of the recoilless fraction and broadening of Mössbauer γ rays Rayleigh scattered from glycerol and sec-butyl benzene in the supercooled liquid, glassy and polycrystalline states, and from polycrystalline benzene. It is concluded that the vibration amplitude (possibly rotational in origin) i…
The bending behaviour of square plain-weave fabrics spun and woven from nineteen different fibres, each in a range of cover factors, has been studied. It is shown how this behaviour is determined by the mechanical properties of the fibre and the frictional and geometrical restraints within and between yams in the fabr…
The elastic Gibbs function at zero stress has been derived for ferroelectric crystals with point symmetry 4/mmm in the paraelectric phase, and the possible ferroelectric states have been examined. For the special case of bismuth titanate, recent optical data are used to derive the absolute orientation and the temperat…
Abstract Specimens of poly(methyl methacrylate) (PMMA) were compressed at nominally constant strain rates ranging from 10 −5 to 10 3 in./in./sec. at 0, 22, 50, and 115°C. A plot of stress at a small fixed strain (2%) and constant temperature versus logarithm of strain rate is sigmoidal in shape and, furthermore, time‐…
The crystallization of amorphous selenium is shown to occur by the formation of lamellas in which the molecular axis lies across the wide face and perpendicular to the growth direction. Below about 200°C the lamellas grow radially from a common nucleus branching noncrystallographically to produce a spherical crystalli…
The metal ions in CoFe2O4 when fired in air are probably randomly distributed over the cation sites of the spinel structure. The parameters (u is the coordinate of the O ions and l is the fraction of the tetrahedral sites occupied by Fe ions) of CoFe2O4 samples are: for a firing temp. of 1350 Deg and quenched in air,…
Index-of re fra ction ve rs us time iso th e rm s ha ve bee n esta bli shed for ge rmania glass. Us in g th e c rosso ve r te c hniqu e with air-q ue nc hed sampl es and app lyin g th e two relaxatio n tim e mod el pre viou s ly reported for borosilicate glass, it was found that th e width of th e spec tr~m of re laxa…
The crystal structures of ferroelectric and paraelectric (Glycine) 2 HNO 3 were determined by X-ray as well as by neutron diffraction methods at -150°C and at room temperature, respectively. One of the glycine molecules has the zwitter-ion configuration and another is mono-protonated. Thus the chemical formula should…
Abstract The angular dependence of scattering intensity of drawn polyethylene (PE) was investigated with a small‐angle Kratky camera. At constant drawing temperature the intensity drops drastically with increasing draw ratio; however, the position and the half‐width of the first maximum remain nearly unchanged. The dr…
The detection and identification of a surface compound formation on a steel surface was made using a backscatter Mössbauer effect technique. The compound was identified as β-FeOOH from Mössbauer effect parameters of iron oxide and oxy-hydroxide compounds. An estimate of the compound thickness is given based on a calcu…
A stochastic model has been developed that relates the stress-strain and the dilation-strain behavior of filled elastomers to the formation and growth of vacuoles which cause strain-induced volume dilatation in these materials. Both the cumulative and instantaneous frequencies of vacuole formation are simply derived f…
The phase boundaries of subliquidus immiscibility in the lithium, sodium, potassium, rubidium, and cesium borate systems were determined. Two‐phase structures were developed in thermal gradients and examined by direct‐transmission electron microscopy. No opalescence was observed. Microstructures were of the order of a…