Materials Literature
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Hydrogen sulphide has long been associated with causing weight-loss corrosion, blistering, and sulphide stress cracking in low-alloy steels used in oil and gas production. In recent years, new stainless and nickel alloys have been proposed for use in many oilfield applications where corrosion in production environment…
Abstract In 1963 Boyer proposed the existence of a liquid‐liquid transition, T ll , in polystyrene above the glass transition T g . Since that time there has been considerable discussion and disagreement on the existence of this transition. Detailed shear modulus data as a function of temperature in the range 165–215°…
Abstract During direct vapour phase dehydrogenation of ethanol, a copper‐on‐silica catalyst lost much of its activity in 100 h. Analysis with X‐ray diffraction, scanning electron microscopy and X‐ray photoemission showed that both sintering and carbon deposition accompanied the drop in activity. In catalysts in which…
An investigation has been carried out into the development and maintenance of wear-protective oxide on iron-12 per cent chromium-base alloys during sliding in air at 20–600°C, with particular reference to the effects of temperature, of intermittent changes in temperature, and of sliding speed. It has been established…
Abstract The behaviour of a polypyrrole‐modified electrode in an aqueous 0.5 M HCl solution at high anodic potentials was studied. Electrochemical experiments and 13 C‐NMR analysis showed a decrease in conductivity, due to the formation of CCl bonds in the pyrrole ring structure.
L'imitérite, Ag2HgS2, est un nouveau minéral du gîte d'Imiter, Jbel Sarhro, Anti-Atlas, Maroc, d'où il tire son nom. Gris blanc en lumière réfléchie naturelle, avec un pléochroïsme allant du bleuâtre au rosâtre, il présente une forte anisotropie du bleu au brun roux. Le pouvoir réflecteur dans l'air va de 38,3-33,4 %…
Minimum displacement threshold energies for copper atoms in ordered and disordered Cu3Au and CuAu were determined at 20 K by electrical resistivity measurements during high energy electron bombardment: ECu d min, (20 K)=18 eV in all cases. Previously obtained defect production curves are reanalysed. The recovery of da…
Mesure de la conductivite thermique, du module de Young a la compression de la dilatation thermique entre 100 et 350°K de mousses de polyurethanne de densites nominales 32, 64 et 96 kg/m 3
Chlorocobalt(III) protoporphyrin IX dimethyl ester, [CoIIIP(Cl)], releases its chloride immediately on dissolution in methanol, and equilibrates as shown below. Species (2) predominates if no acid [graphic omitted] or alkali is added. [CoIIP] dissolved in methanol, in the presence of air, undergoes oxidation yielding…
The first results on the superconducting properties of ultra-thin epitaxial CoSi2 films are reported. The metal films are obtained by solid phase epitaxy under ultra high-vacuum conditions, with thicknesses ranging from 600 Å down to 50 A. These films are stable against temperature cycling from 350 mK up to room tempe…
The chemical mechanisms responsible for the incorporation of uranium into the silica rich part of the SiO2-Al2O3-K2O and SiO2-Al2O3-Na2O systems, are investigated. Fluorescence and optical absorption spectroscopy indentify UVI, UV and UIV ions, which are stabilized with decreasing oxygen fugacity. Raman spectroscopy s…
The mechanisms of intergranular stress corrosion cracking (I.G.S.C.C.) of sensitized stainless steels in boiling water reactor (BWR) primary coolant are reviewed, with emphasis on the role the environment plays on both the initiation and propagation processes. Environmental factors discussed include oxygen (corrosion…
Some N,N,N′,N′-tetra-alkylfumaramides and alkyl N,N-diethylfumaramates polymerize through an opening of their double bond with a radical initiator, in a similar way to dialkyl fumarates, leading to high molecular weight and semi- or non-flexible polymers consisting of a substituted polymethylene structure.
The reaction of praseodymium trifluoroacetate with 15-crown-5 ether in acetonitrile-methanol (3 : 1) gave a complex formulated as [ Pr(CF3CO2)3]2(C10H20O5). This compound was recrystallised and the X-ray crystal structure determined by the heavy-atom method and refined by least-squares methods to a final R value of 0.…
Abstract We have measured the percentages of cis and trans Gly‐Pro and X‐Hyp peptide bonds in thermally unfolded type I collagen. 13 C‐nmr solution spectra show that 16% of the Gly‐Pro and 8% of the X‐Hyp bonds are cis in unfolded chick calvaria collagen. These results support the hypothesis that cis – trans isomeriza…
The directional solidification of MgO–ZrO2 eutectic has been investigated by the Bridgman type method. The melting was conducted using a Mo crucible in an argon atmosphere at the growth rate of 10–20 mm/h. Colony-free structures were obtained at these growth rates. The lamellar morphology as well as the fibrous morpho…
In order to investigate whether the stagnation of strain hardening upon stress reversal which had been observed in aluminium is a general phenomenon in single phase, fcc and bcc pure metals, the strain-hardening behaviour during reversed straining of prestrained aluminium, copper and iron polycrystals was analyzed usi…
Abstract The NADH models, (1 R )‐1,4‐dihydronicotinamide and (1 R )‐1,4‐dihydroquinoline‐3‐carboxamide ( 1‐4 , R = X‐benzyl or octyl), are readily oxidized by methylene blue ( MB ⊕ ), yielding the corresponding pyridinium ions and leuco‐methylene blue ( MBH ). Under aerobic reaction conditions, molecular oxygen, prese…
Some fundamental aspects of mechanical actions on wood pulp fibers have been studied. Specifically, the objectives of the study were to produce internal fibrillation in pulp fibers, evaluate its influence on paper properties, and establish its importance relative to external fibrillation and fines in terms of paper pr…
Single crystals of Rb 2 [Ga 2 Ge 3 O 10 ] crystallize in space group I 2 with a = 12.767(2) Å, b = 12.767(2) Å, c = 6.727(1) Å, γ = 90° and Z = 4. According to the pseudotetragonal lattice, all investigated crystals are twinned with pseudosymmetry I [unk]. The structure was solved by direct methods and the refinement…