Materials Literature
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Abstract Crystal defects in calcite containing Na and K ions were investigated by means of a model based on statistical thermodynamics and measurements of thermoelectric power. The varying amount of Na and K ions in the crystal was interpreted on an assumption of ideal solution of the ions as Ca1−x−y\squarex+y[Na2x, K…
The nature of fibre migration, the number of fibres in yarn cross-section and the factors that influence the strength of rotorand ring-spun yarns have been studied. Rotor yarn comprised 15%less fibres in yarn cross-section than the corresponding ring yarn. Fewer fibres in ~arn cross-section in rotor yarn result in les…
The radial packing density of rotor-spun yarn was measured on the basis of the theory reported earlier by the author [J ndian J Text Res, 11 (1986) 26]. The effect of yarn twist and count on the fibre packing density of rotor-spun yarn in comparison with tbat of ring-spun yarn was studied. The packing density of both…
Abstract A supplementary device to a scanning electron microscope allows the simultaneous taking of wide‐angle interferences in the directions of transmission and back reflection of identical specimen areas. A developed computer program simulates the complete reflex system so that the identity with the pattern is obta…
A novel laser-induced CVD apparatus with a direct pattern writing ability by a pyrolytic decomposition of SiH 4 has been developed. With this equipment, a CW argon laser with an output power of 20 W was used. The argon laser beam, which provides localized heating of the substrate, was utilized to decompose gas-phase m…
Electron microscope studies of as-ultraquenched and subsequently crystallized isotactic polybutylene (PB) are described in this paper. Cold shadowing of the as-quenched samples reveals no distinct structure larger than 30 Å in the amorphous PB. When rapidly warmed to room temperature PB crystallizes as microcrystals o…
Despite the availability of several commercial suspension formulations of metronidazole benzoate, there is no official method for its analysis. The conventional analytical method requires extensive extraction following each extraction with evaporation then non-aqueous titration with perchloric acid. The method is time…
011-in-glycerol/water emulsions at various ratios of water to glycerol in the external phase were prepared with Tween 80 and either light mineral oil or soybean oil. A minimum in the droplet size was observed at about 15% w/w water in the external phase of the emulsions. At the same water concentration, a clouding of…
Detailed investigations of the pyroelectric and dielectric properties were performed on PbZrO3 single crystals grown from PbO + ZrO2 + PbF2 + B2O3 flux. Virgin samples possessed a spontaneously developing transient phase. The influence of space charge polarization, in particular connected with the special role of vaca…
Transformation‐range viscosity and thermal expansion measurements were made for five series (Li‐Na, Li‐K, Li‐Cs, Na‐Cs, and K‐Rb) of mixed‐alkali borate glasses containing 30 mol% total alkali oxide. In each case, negative deviations from additivity were observed in the isokom and glass transformation temperatures. Po…
Structural parameters determined for crystalline iron, fayalite and aegirine agree closely with X-ray crystallograhic data. A glass of NaFeSi2O6 composition has Fe predominantly present as Fe3+ in tetrahedral coordination i.e. as a network former. CaFeSiO4 and CaFeSi2O6 glasses have about 1/3 of the total Fe in octahe…
The behavior of isoprene and styrene polymerizations initiated by the complex of n-butylsodium and n-,s-dibutylmagnesium (sodium tributylmagnesiate) has been examined. The styrene-benzene system was found to yield stable active centers and polymers of predictable molecular weight and narrow molecular weight distributi…
Parabariomicrolite _BaTa401O(OHh.2H20 is rhomb,9hedral, spac~ group R3m, with a 7.4290(6), c 18.505(2) A, V 884.5(1) A, Z = 3. The ~trongest six lines in the X-ray powder pattern [d in A(I)(hkl)] are 6.18(50)(00.3), 3.172(65)(02.1), 3.085(41)(00.6), 3.040(10.0)(20.2), 2.641(50)(02.4), 1.591(42)(22.6). Electron-micropr…
Abstract Samples of PVC, plasticized with a range of aliphatic and aromatic esters, were naturally weathered by exposure for one year in Arizona. Standard weathering tests involve inclining the plasticized PVC sheets at 45 degrees to the horizontal facing south. In this way, the greatest exposure to sunlight is achiev…
Abstract New donors, “TTF-dimer”s in which two TTF units are perpendicularly fixed have been synthesized. Redox potentials indicate that their donor abilities are somewhat reduced compared with those of corresponding “TTF-monomer”s. Present donors form CT complexes with DDQ.
SUMMARY Ten naturally acidic Scottish soils have been limed with CaCO 3 at 0,0.25, 0.50, 0.75, 1.00 and 1.25 times the recommended lime requirement, and then subjected to three cycles of alternate wetting to field capacity at 20°C for 1 month and drying for 1 month. The Zn, Cu, Fe and Mn extracted by DTPA solution, bo…
Isotactic polybutene (PB) can be quenched into a completely glassy state by quenching molten films into a solid-liquid mixture of isopentane, Freon, or ethanol. The crystallization of PB from the glass form was studied by x-ray scattering, differential scanning calorimetry (DSC), and dynamic mechanical spectroscopy (t…
Abstract Polymers having oxide network chains are produced by hydrolytic polycondensation of metal alkoxides and alkoxysilanes. Molecular morphology and molecular size distribution of these inorganic polymers are strongly affected by certain nonchemical parameters. Included among these parameters is the molecular sepa…
One of the unit operations in foam technology is foam generation in a liquid/gas mixer. The foaming process of an aqueous liquid system with a surface‐active agent in a rotor‐stator mixer has been studied, and it was found that it could be represented by a mixing characteristic relating the liquid flow rate to the max…
The theory of the Lifshitz point, a triple point in the phase diagram of systems with incommensurate phases, is extended to systems in which the direct para-ferro transition is first order. The structure of the phase diagram is shown to be considerably more complex than in the usual case of a second-order direct trans…