Materials Literature
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A simple and effective route to preparing bulk nanocrystalline (NC) pure Mg with an average grain size of 20 nm is first proposed by hydrogenation-disproportionation-desorption-recombination (HDDR) followed by spark plasma sintering (SPS) and hot extrusion (HE) techniques. NC Mg is thermodynamically super-stable again…
Siliceous hollow helicoids (Archimedian screw shapes) with spiraling mesoscale channels are the result of a new way of controlling the growth and form of hexagonal mesoporous silica. These novel helicoids (see Figure) are produced when a patch of the hexagonal silicate liquid-crystal film contracts on hydrolytic polyc…
A novel series of poly(arylidene-ether)s containing cyclopentanone was synthesized by polycondensation of 4, 4′-diformyl-α, ω-diphenoxyalkane and 4, 4′-diformyl-2, 2′-dimethoxy-α, ω-diphenoxyalkane with cyclopentanone. The polymers were characterized by elemental and spectral analyses, inherent viscosity, solubility a…
The structure and magnetostriction of (Tb1−xNdx)(Fe0.4Co0.6)1.9 (0<x<1) alloys have been investigated at room temperature and the magnetic properties determined over the temperature range 1.5–300 K. It was found that the matrix of (Tb1−xNdx)(Fe0.4Co0.6)1.9 is essentially that of a (Tb,Nd) (Fe,Co)2 phase…
In this paper, the crystal growth of sodium nitrate and potassium nitrate from aqueous solutions, in a perfectly stirred batch crystallizer, has been studied considering the effect of temperature, supersaturation degree, and the size of seed crystal growth rate. The mass transfer coefficients obtained correlated with…
Abstract Itoigawaite, SrAl 2 Si 2 O 7 (OH) 2 ·H 2 O, is a new member of the lawsonite group found in the Itoigawa-Ohmi district, central Japan. It is orthorhombic, Cmcm , a = 6.031(2), b = 8.945(2), c = 13.219(4) Å, Z = 4. The strongest lines in the X-ray powder diffraction pattern are 4.68 (s) (111), 4.26 (vs) (021),…
Abstract Intercalation of amino acids into 10.0-Å hydrated kaolinite was studied by powder X-ray diffraction (XRD), differential thermal analysis-thermal gravimetry (DTA-TG), and infrared (IR) spectroscopy. Intercalation was found to be dependent on the chain-length, pH, and the concentration of the amino acid zwitter…
Abstract Thermal dehydrochlorination of trans ‐6(4)‐chloro‐4(5)‐tetradecenes, models for PVC degradation, was studied by NMR spectroscopy both alone and in the presence of alkyl and zinc phosphites. The implications of these results on PVC degradation and stabilization are discussed.
Two chemical treatments were applied to hemp, sisal, jute and kapok natural fibres to create better fibre to resin bonding in natural composite materials. The natural fibres have been treated with varying concentrations of caustic soda with the objective of removing surface impurities and developing fine structure mod…
Abstract Sandstones and mudstones of the Skagerrak Formation from the Danish Sub-basin have been studied to assess the origin of the clay minerals, their diagenesis and their transformation/ conversion temperatures (compared to modelled maximum burial temperatures). Detrital smectite and vermiculite occur only at shal…
Thermal conversion of poly(anthranilic acid) (PANA) to polyaniline (PAn) has been studied by means of thermogravimetric/mass (TG/MS) and Fourier transform infrared (FTIR) spectroscopy. The electrical conductivity of the chemically prepared PANA was 3.5 × 10−2 S/cm, which is caused by the self-doping of the polaronic n…
Perhaps one of the most surprising results in the past 10 years was the prediction of Brand et al. [1] that fluid biaxial smectics made from comopunds without asymmetric carbons could, by symmetry, have a spontaneous polarization, P, in the layer plane. They called this construct, which can be either ferroelectric or…
Ongoing studies of the CsHSO(4)-CsH(2)PO(4) system, aimed at developing novel proton conducting solids, resulted in the new compound Cs(2)(HSO(4))(H(2)PO(4)) (dicesium hydrogensulfate dihydrogenphosphate). Single-crystal X-ray diffraction (performed at room temperature) revealed Cs(2)(HSO(4))(H(2)PO(4)) to crystallize…
Abstract The mechanical behavior of polycarbonate (PC) coextruded as microlayers with a brittle polymer, either poly(styrene‐ co ‐acrylonitrile) (SAN) or poly(methyl methacrylate) (PMMA), was examined. Adhesion between layers was measured with the T‐peel method. The much higher interfacial toughness of PC/PMMA microla…
As propriedades tênseis de compósitos de matriz poliéster, reforçados por fibras curtas de sisal foram determinadas em função do comprimento, teor e orientação das fibras. Os resultados mostram que, para os compósitos investigados, a resistência à tração aumentou com o comprimento das fibras (5 – 45 mm), atingiu um pl…
Crystallization behavior of potassium niobium silicate (KNS) glasses having compositions expressed by the general formula x K 2 O· x Nb 2 O 5 ·(1 ‐ 2 x )SiO 2 , with x = 0.167, 0.182, 0.200, 0.220, and 0.250, has been studied by DTA, X‐ray diffraction, second harmonic optical generation (SHG), and electron microscopy.…
Thin amorphous and polycrystalline tungsten oxide films were prepared by chemical vapour deposition at atmospheric pressure from a metalorganic precursor — tungsten hexacarbonyl. The dependence of the structural and optical properties of tungsten oxide films on the technological conditions has been investigated by XRD…
The nonlinear dynamics of a spherical bubble cloud with nuclei size distribution are studied numerically. The spectrum of nuclei is assumed uniform initially. The simulations employ a nonlinear continuum bubbly mixture model with consideration of the presence of bubbles of different sizes. This model is then coupled w…
The interaction and adhesion between the fiber and matrix has a significant effect in determining the mechanical and physical behavior of fiber composites. The effect of the interface and interphase depends on several factors such as chemical composition (functional groups), molecular structure characteristics (branch…
This paper deals with two different types of composite insulating materials for HV outdoor insulation technology. For outdoor applications fiberglass reinforced polymer (FRP) are used mainly as transmission line insulators (composite long rods),and as power apparatus housings (composite hollow core insulators). During…