Materials Literature
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The present theories for in-vacuum gap conductance, hs, are compared to existing out-of-pile data. It is concluded that the Mikic theory which has not been previously applied to nuclear applications is most suitable for future development. The additional data necessary to estimate the transition pressure and to confir…
The metal-to-insulator transition in V2O3 is described by a model that is based on the electronic band structure of this material. The vanadium 3d-t 2g band decomposes in the trigonal symmetry into two bands, a 1g and e π. The a 1g band consists of orbitals connecting pairs of c-axis neighbouring atoms, while the e π…
Summary The residua system of chemical weathering is here defined as the chemical sink towards which the bulk of earth's surface materials (i.e. the silicate rocks) trend during weathering. Chemically the system is defined in terms of four major components, SiO 2 –Al 2 O 3 –Fe 2 O 3 –H 2 O, evidence being derived from…
Values for splittings of 3d, 4d and 5d bands in some metals in the range Z=29-93 have been derived from photoelectron energy distributions. Comparisons with free atom experimental and theoretical values are made and evidence for crystal field effects on the splittings presented.
Hydrogen environment embrittlement refers to metals stressed while exposed to a hydrogen atmosphere. Tested in air, even after exposure to hydrogen under pressure, this effect is not observed on similar specimens. Much high purity hydrogen is prepared by evaporation of liquid hydrogen, and thus has low levels for pote…
Abstract The causes of some of the differences in properties between compounded natural rubber and compounded synthetic poly (isoprene) have been traced to the insoluble non-rubber material in natural rubber. This material is mostly denatured proteins and is responsible for the higher modulus, faster scorch time, high…
The corrosion of mild steel in cultures of sulphate-reducing bacteria has been studied and in particular the effect on the corrosion rate of changing from an iron-rich to a minimal-iron growth medium in semi-continuous cultures. The results indicate that the ferrous sulphide produced by the bacteria is the major corro…
Abstract Measurements of the effect of hydrostatic pressure on the first order Raman frequencies of Se and Te are reported. All the frequencies of the Raman active modes decrease with pressure. The valence force field model proposed by Nakayama and Odajima is used to explain this behaviour.
It is shown that the often cited inverse-logarithmic oxidation law, X−1 ∝ −logt, where X is the oxide thickness and t the observation time, is not an asymptotic solution of the rate equation derived by Mott and Cabrera in their theory of low temperature oxidation. Thus whether or not the inverse-logarithmic law is exp…
The nonlinear viscoelastic functions G1′, G1″, G3′, and G3″ were evaluated for disperse systems of polystyrene solution and styrene-divinyl benzene copolymer particles at various temperatures ranging from 10 to 70°C over the frequency range from 12 to 1/256 Hz. In general, frequency dependence curves of all the functi…
Intrinsic coercive force measurements were made on BaFe 12 O 19 in which certain amounts of Fe were substituted by In, Cr, Al, Ga, ZnGe, ZnV, ZnNb or ZnTa. The specimens were prepared by the ordinary powder metallurgy method. X-ray diffraction of the specimens indicated only the presence of the magnetoplumbite phase w…
EVALUATION of the many factors associated with the transfer of heat caused by the evapo[ation of body sweat has been a subject of major interest over the past three decades, Skin wettedness (Ref 7) was early observed as a significant factor associated with the sense C'pleasantness'' and more recently with t'comfort''…
A tight-binding model is presented to study the density-of-states and some other electronic properties of a liquid metal and an amorphous solid composed of atoms with one-atomic orbital per site. A one-electron Green function is expanded in terms of atomic orbitals and described by a perturbation expansion series in p…
The effect of benzotriazole on the corrosion of copper in 3% NaCl at pH3 has been studied by immersion tests, potentiostatic polarization, a.c. impedance measurements and ellipsometric investigations. Results show that a thin layer of BTA forms in neutral solutions but that, in acidic solutions, the film is covered wi…
A mass transport equation which takes into account parallel diffusion paths for both anions and cations was derived and applied to the diffusional creep of polycrystalline ionic solids. From the results of the analysis, several limiting conditions were found for grain‐boundary‐ and lattice‐diffusion‐controlled kinetic…
Abstract An investigation has been carried out to determine the influence of operating conditions on the character of the final product resulting from the polymerization of ethylene in a radio‐frequency discharge. It has been found that low pressures and high ratios of discharge power to gas flow rate lead to the depo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTriplet-state phosphorescence of adsorbed ionic organic molecules at room temperatureEdward M. Schulman and Cheves WallingCite this: J. Phys. Chem. 1973, 77, 7, 902–905Publication Date (Print):March 1, 1973Publication History Published online1 May 2002Published inissue 1 Mar…
Selected-area electron diffraction and x-ray diffraction have been used to study microstructure of spherulites in thin films of isotactic polypropylene crystallized from the melt. Our purpose has been to seek an explanation for a branching habit, unique to this polymer, in which parent and daughter lamellar crystals m…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbon-13 spin-lattice relaxation in benzene and substituted aromatic compoundsGeorge C. Levy, Joseph D. Cargioli, and F. A. L. AnetCite this: J. Am. Chem. Soc. 1973, 95, 5, 1527–1535Publication Date (Print):March 1, 1973Publication History Published online1 May 2002Publishe…
One of the most striking features of recent research on structure/property relationships in two-phase alloys has been the swing towards the establishment of rigorous quantitative theoretical models and the associated attempts to obtain the necessary experimental data to test these models. This compares favourably with…