Materials Literature
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ZrO 2 powder was prepared by a sol–emulsion–gel method at temperatures below 140°C from ZrO(NO 3 ) 2 · n H 2 O. The asprepared powder was amorphous, but crystallized into the tetragonal structure by 600°C. The metastable tetragonal powder (600°C) was comprised of ultrafine 4‐ to 6‐nm size particles. On heat treatment,…
SUMMARY The dissolution rates of feldspars in the presence of naturally occurring organic solutes were compared at pH 5.1. Natural silt or ground feldspar minerals were suspended in water, streamwater, soil water, water extracts of peat and mor and a citrate solution for approximately 100 d. The increase of major cati…
The glass quality, physical properties, and thermal stability of fluorozirconate and fluorozirco‐hafnate glasses were investigated as a function of the AIF 3 content. The AlF 3 concentration varied from 2 to 3.25 mol%. The ratio of the other components was constant, except for 50% substitution of ZrF 4 by HfF 4 in the…
Abstract Multiple crevice assemblies (MCAs) have been used for over a dozen years to assess the crevice corrosion resistance of stainless-type alloys in seawater and other chloride-containing environments. This paper provides a review of the technique's development, modification, and present usage and discusses its li…
Abstract Molecular weight distributions of poly(dimethyl diallyl ammonium chloride) were determined from sedimentation velocity measurements. After a presentation of the experimental basis for the evaluation of distribution curves, molecular weight distribution curves for different samples were discussed and compared…
A mushy region (a two-phase zone) between the solid and liquid phases occurs often in the process of solidification of a binary melt. An analysis of the structure of the mushy region, which includes the liquid, solid particles, and dendrites extending from the bulk solid surface, is suggested. The processes of heat an…
Abstract Systematic thermal degradation studies of PVC solutions have been carried out in the presence of different metal carboxylates (Pb‐, Cd‐, Ba‐, Ca‐ and Zn‐ stearates). ZnSt 2 markedly accelerates degradation of the polymer. Significant induction periods ( t i ) for the appearance of free HCI are obtained in the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of alkaline-earth indium sulfidesD. O. Kipp, C. K. Lowe-Ma, and T. A. VanderahCite this: Chem. Mater. 1990, 2, 5, 506–511Publication Date (Print):September 1, 1990Publication History Published online1 May 2002Published inissue 1 September 1990h…
The ideas of the electron theory of chemisorption are applied to the behaviour of H, B, C, N, and 0 atoms segregated on and in iron. The general theory can be divided naturally into two branches depending on whether the valence levels of the embedded atoms ‘float’ at the Fermi level, as in the case of B, C, and N; or…
Abstract The angular distributions of elastically reflected electrons from an evaporated gold film surface are measured at primary energies 400, 600, and 800 eV for different angles of incidence between 0° and 75°, and the influence of 2 keV Ar + ion bombardment is investigated. By means of Monte Carlo simulations the…
Abstract A systematic study was conducted to determine the optimum polyvinylchloride (PVC) molecular weight and impact modifier concentration blend for the construction or outdoor application. This application called for a material with superior impact and weathering properties as well as cost efficiency. Three differ…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThree Pentacyclic Triterpenoids from the Leaves of Plumeria obtusaSalimuzzaman Siddiqui, Bina Shaheen Siddiqui, Akhtar Naeed, and Sabira BegumCite this: J. Nat. Prod. 1990, 53, 5, 1332–1336Publication Date (Print):September 1, 1990Publication History Published online1 July 2…
The kinetics of oxidation of potassium iodide by hydrogen peroxide in aqueous perchloric acid has been studied both in the absence and in the presence of sodium molybdate by means of the initial-rates method. The law found for the total initial reaction rate is[Formula: see text]The activation energies associated with…
Abstract In contrast to expectations from rheometer studies of vulcanization behavior, the NMR technique has demonstrated that blends of NR and NBR vulcanized with sulfur/TMTM show a marked distribution of crosslinks in favor of the NR phase. The presence of even a minor proportion of NBR is sufficient to reduce the d…
Wood fibers and nonpolar thermoplastics, e.g. polystyrene, are not the ideal partner for the preparation of composites because of a wide difference in their polarity. In the present study, polarity of the polystyrene was modified by the introduction of a—COOH group, through the reaction with maleic anhydride (MA) in t…
Abstract The relative intensities ratios for the determination of the relative amounts of alpha and beta phases in silicon nitride and the relative amounts of delta yttrium disilicate (Y 2 Si 2 O 7 ) and nitrogen apatite [Y 5 (SiO 4 ) 3 N] are reported. These constants were determined using an iterative method applica…
Abstract 1. The small-deformation-viscoelastic response of elastomers containing nonreinforcing filler has been investigated. Nonlinear viscoelastic behavior was observed as a pronounced strain-amplitude dependence. The degree of this dependence was quantified using a power-law representation as a single nonlinear par…
In this paper spheroidal VC carbide was produced by rare earth (RE) + N complex modification of white cast iron and the mechanism of modification was investigated. Primary crystallisation of VC in the melt, required for its independent growth into spheroids, was prompted by high V content of the alloy and heterogeneou…
Abstract Phase phenomena in mixtures containing any combination of aliphatic and aromatic polyamides can be formulated by the application of a mean‐field binary interaction model. This has been achieved by the quantitative analysis of the solubility of an aromatic polyamide, denoted as nylon 3Me6T, in a homologous ser…
Scanning acoustic microscopy (SAM) has allowed observation of the microscopic details of the attack by cathodic alkaline corrosion products on a model organic coating on steel. Attack of the polymer by the alkaline corrosion products occurs at numerous localized regions resulting in mechanical degradation of the coati…