Materials Literature
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Abstract The gelation of vinyl plastisols at constant temperature has been found to follow the equation ln [( C − C e )/( U − C e )] = (− π 2 / a 2 ) D τ + ln (8/π 2 ), where C is the resin phase concentration, C e the equilibrium resin phase concentration, U the critical resin phase concentration, a the average parti…
The bidirectional spectral reflectance of a set of V-grooved surfaces has been investigated in an attempt to separate the influences of the mean slope and the peak-to-valley height. The experimental results show good agreement with the theoretical models in both the geometrical optics and diffraction ranges.
A number of binary systems comprising a liquid crystalline Schiff's base, viz. p-acetoxybenzal-p-phenetidine and a non-liquid crystalline Schiff's base are studied. In all these cases, the liquid phase, be it anisotropic or not, is a single homogeneous phase. There is no indication of two distinct liquid phases, one a…
Dislocation measurements obtained after creep of Fe-3·0% Si by Barrett et al. (1966) have been analysed. It is shown that mean mobile dislocation velocity is linearly related to mobile dislocation density in support of a previous model of creep (Webster 1966). Furthermore, the creep curves calculated using these resul…
Abstract Stress relaxation experiments were carried out in a dry nitrogen atmosphere on polydimethylsiloxane and an ethylene‐propylene terpolymer. Relaxation times much longer than expected were observed, and plots of In f ( t )/ f (0) versus time were linear in all cases.
Abstract Volcanic gases from several active volcanoes in Japan have been analyzed for iodine and chlorine: Showashinzan (I=0.025–0.20 mg.I/kg.H2O, Cl=238–1830 mg.Cl/kg.H2O), Iwatesan (I=0.053–0.19, Cl=2720–3360), Issaikyoyama (I=0.030–0.087, Cl=104–213), Nasudake (I=0.16–3.9, Cl=188–9460), Yakedake (I=0.58–0.93, Cl=12…
1. Euplotes daidaleos n. sp. is described as a hitherto unrecognized species. It is a fresh-water form found in Philadelphia, Pa., and appears to be closely related to E. patella, differing from it in shape and size, in the possession of zoochlorellae and possibly in the structure of the peristome. 2. Diagnostic chara…
Abstract The kinetics of the anionic polymerization of octamethylcyclotetrasiloxane (D 4 ) initiated by α‐methylstyrene living polymer in tetrahydrofuran was studied. The following kinetic scheme was postulated: Initiation: equation image Propagation: equation image where S ‐ and M represent the initiator and D 4 , re…
A detailed study was made of the effects of yarn friction on the magnitude of the tensions developed in the knitting zone of the standard weft-knitting machine and the in fluence of these tensions on loop formation and fabric quality. Variations in loop length of ±10% due to changes in yarn friction may be experienced…
Thirteen p-n-alkoxybenzylidene-p-aminobenzoic acids were prepared and their mesomorphic transition temperatures were determined. They exhibit mesophases of greater relative thermal stability than the p-n-alkoxybenzoic and p-n-alkoxycinnamic acids but 4′-n-alkoxydiphenyl-4-carboxylic acids exhibit greater thermal stabi…
A new instrumental method for the analysis of the stress-strain behavior of fabrics in shear has been designed which utilizes the Instron and its automatic recording. It is similar in principle to the laboratory method previously employed by Treloar. A cotton and a spun viscose fabric were investigated for their depen…
Abstract The crystal structure of the α polymorph of nylon 4 has been determined from the x‐ray diffraction patterns of uniaxially oriented monofilaments. In general the crystal structure of α nylon 4 is similar to that of α nylon 6. The unit cell is monoclinic with the following dimensions: a = 9.29 ± 0.05 A., b = 12…
Abstract The dynamic mechanical properties of highly crosslinked epoxyamine polymer networks with nonrandomly distributed crosslinks were investigated. The transition temperatures of these polymers can be correlated with the number of CH 2 groups between crosslink junctions in the aliphatic amine portions of the netwo…
Adiabatic calorimetry was applied to some liquid crystalline substances. Especial reference is made for the first time to the transition between smectic modifications of different types. The enthalpy of transition, including pre-and post-transition effects, is 2100 joules/mole for the smectic B to smectic A transition…
In recent years, glassy systems based on the group VI A elements S, Se, or Te in combination with group IV A and group V A elements or V A elements alone, have been investigated as potential sources for new iroptical materials. The results obtained in the qualitative evaluation of glasses from many systems reported in…
Abstract Within a family of catalyst systems wherein TiCl 3 was made by mixing TiCl 4 and aluminum alkyl solutions, the primary particles of TiCl 3 were usually thin, flat polygons with average diameters ranging from 300 to 1000 A. Even in unused catalyst these primary catalyst particles were bound together into large…
Abstract A series of derivatives of meso ‐tetraphenylporphine, with neutral, acidic and basic functional groups, has been prepared. Several of these compounds were synthesized directly via the Rothemund reaction, under a variety of conditions to obtain optimal yields; others were prepared by interconversions of variou…
Abstract Li 2 SnO 3 tritt in zwei Modifikationen auf, einer α‐Form unterhalb 800°C, welche zu den Raumgruppen C 2h 3 = C2/m oder D 3 3 = C3 1 12 oder der enantiomorphen D = C3 2 12 gehört, und einer oberhalb 1000°C stabilen β‐Form in C = C2/c. Diese Strukturen entsprechen verschiedenen Stapelungen von wabenartigen Sn‐…
Some practical problems associated with the use of beryllium as a mirror substrate material are analyzed, with particular emphasis on nonelastic strains that may affect mirror performance. Present information on the nonelastic behavior of beryllium is summarized.
The paramagnetic relaxation of ClO2 in dilute solution was studied as a function of temperature, viscosity, and solvent system. In paraffin solutions, where the ClO2—solvent interaction is apparently small, the ClO2 electron paramagnetic resonance linewidth is linearly proportional to temperature but essentially unaff…