Materials Literature
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Abstract Wet, porous, and semipermeable poly(vinyl chloride) (PVC) membrane prepared from a binary system, PVC and dimethylformamide, by immersing in alcohols or ethers was studied. The pore dimensions of the wet PVC membrane were from 0.01 to 0.05 μm, calculated from hydrodynamic permeability by using experimental va…
Abstract Polyamide microcapsules containing solutions of azo‐bis‐isobutyronitrile (AIBN) were prepared and characterized as regards diameter and wall thickness. Under UV irradiation the AIBN eliminates nitrogen, and this, under suitable conditions, leads to rupture of the capsules. The influence of capsular diameter a…
Abstract A theory explicitly allowing the possibility of aggregation of multistrand biopolymers is proposed. It is found that the same secondary bonds responsible for stabilizing the native structure at low temperature will promote aggregation in the thermal denaturation region for sufficiently long chains. A requirem…
With the aim of beginning a systematic characterization of the magnetoelastic properties of the hexagonal ferrites we measured the room temperature magnetostriction in a number of these materials. The analysis of the experimental results allows us to conclude that: a) the saturation magnetostriction in hexaferrites is…
A systematic approach is presented for obtaining cylindrical distribution functions (CDF's) of noncrystalline polymers which have been oriented by extension. The scattering patterns and CDF's are also sharpened by the method proposed by Deas and by Ruland. Data from atactic poly(methyl methacrylate) and polystyrene ar…
An increase in the fabric- or assembly-heat sensor separation improved protection against convective heat (flames) exposure. Zirpro wool assemblies required a longer exposure time to reach second-degree burns, with a longer pain-alarm time than comparable assemblies of aramid or flame-retardant cotton. An increase in…
The effect of macroscopic surface roughness upon the resistivity of thin metal films has been calculated by computer modelling of the form of these films. It is shown that, as a consequence of the tendency for the films to be islandised, the resistivity as a function of decreasing mean film thickness rises well above…
An area in north-central New Brunswick of approximately 20 km 2 , where tors are common, was found to be undisrupted by glaciation. The soils in this area are developed on grus and appear to be of pre-Wisconsin age. In both residual Podzolic and colluvial Brunisolic soils, gibbsite was found to be present in significa…
An investigation has been performed into the general corrosion behavior of metallic materials in acid containing organic solutions. Media effects were investigated and found to considerably affect the dissolution process of metals. The metals and solvents used in this study were: Metals—Zn, Fe, Al, Cr-Ni steel; solven…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudy of thermal polymerization of styrene by Raman scatteringB. Chu, G. Fytas, and G. ZalczerCite this: Macromolecules 1981, 14, 2, 395–397Publication Date (Print):March 1, 1981Publication History Published online1 May 2002Published inissue 1 March 1981https://pubs.acs.org/…
The effects of composition, temperature, applied field, and duration of the applied field on the dc resistivity of chromium-doped manganese-zinc ferrites have been studied. From the observed temperature variation of resistivity, activation energy of each sample is calculated. The overall results are discussed in light…
Abstract Most ammonia volatilization studies have focused mainly on specific fertilizers, management, and environmental factors associated with N loss. The objective of this study was to evaluate the influence of particle size of both added and native CaCO 3 and the modifying effects of Fe oxides on NH 3 volatilizatio…
Mn-Al-C alloy for permanent magnets has merit for several reasons: a) carbon stabilizes the metallurgical phases, deformation temperature is high enough for plastic transformation to produce anisotropic τ-phase efficiently; b) useful magnetic energy exceeds the best hexaferrites; the alloy can be more efficient than A…
An extension of the classification of the spectra of neutral praseodymium, based on the analysis of high resolution recordings in the IR and visible ranges, provides new levels of the even configurations 4 f 2 5 d 6 s 2 and 4 f 2 5 d 2 6 s . A parametric interpretation of the fine and hyperfine structures is given for…
The d.c. resistance of amorphous red phosphorus has been measured up to pressures of 90 kbar. At 70 kbar, a transition to orthorhombic black phosphorus was observed. The effect of an initially inhomogeneous microstructure is discussed. At a fixed pressure, a time dependence of the resistance was observed, and this is…
Abstract Partial development of the α form crystals in γ nylon 12 has been found to take place by drawing near the melting point. The confirmation of the α form has been made by X‐ray diffraction, infrared absorption, and differential scanning calorimetry. The amount of the α form varies depending upon the temperature…
Abstract The hevea brasiltensis rubber contains, besides the insoluble branched entities, linear and branched molecules in the soluble fraction. The branching characteristics found by analyzing fractions of different molecular weight of rubber coagulated from freshly tapped latex, stabilized with hydroxylamine hydroch…
Among the Y-Ni compounds, four different behaviours, characteristic of the occurrence of d ferromagnetism in intermetallics have been observed : Exchange Enhanced Pauli Paramagnetism in YNi5 and YNi2, Very Weak Itinerant Ferromagnetism in YNi3, Collective Electron Metamagnetism in Y2Ni17 and Thermal Spontaneous Magnet…
The electrical conduction of 20 µm thick polypropylene films with different crystallinities has been studied at 72°C below 400 kV/cm. The field dependence of the current shows that the conduction mechanism in this polymer is ion hopping. The estimated ionic jump distance strongly depends on the polymer crystallinity,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSAXS studies of segmented polyether poly(urethaneurea) elastomersG. L. Wilkes and S. AbouzahrCite this: Macromolecules 1981, 14, 2, 456–458Publication Date (Print):March 1, 1981Publication History Published online1 May 2002Published inissue 1 March 1981https://doi.org/10.102…