Materials Literature
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Role of local viscosity in the dynamics of melt spinning of a polymer crystallizing under tensile stress are investigated using mathematical modeling methods. The viscosity is assumed to be dependent on local temperature and degree of crystallinity along the spinning axis. Role of the polymer viscosity is studied for…
EMPLOYMENT OF PEROVSKITE -TYPE OXIDE IN THE PROPANE AND CO OXIDATIONS.Simultaneous oxidation/coprecipitation of an equimolar mixture of La(III) and Co(II) nitrates and La(III) nitrate and Mn(II) chloride afforded a hydroxide gel, which was converted to LaCoO 3 and LaMnO 3 on calcination at 600 °C.After calcination, th…
The temperature dependency of the second overtone band assigned to an OH stretching vibration of water has been investigated by means of spectrum decomposition. The absorption bands of water and ice were decomposed into five and three Gaussian components, respectively, which were assigned to the vibration motion of mo…
Abstract Ultrasound‐induced cavitation is known to enhance chemical reactions as well as mass transfer at ambient pressures. Ultrasound is rarely studied at higher pressures, since a high static pressure hampers the growth of cavities. Recently, we have shown that pressurized carbon dioxide can be used as a medium for…
A limited selection of ring modified diphenyldiacetylenes of the type where A=, Y=C n H2n+1, CF3, F, COMe, NH2, and NMe2, and A=, trans and cis with Y=F and trans with Y=C3H7, were synthesized. Mesomorphic properties were determined by hot stage polarizing microscopy and DSC. These properties were generally poorer tha…
The solubility of nalidixic acid in water-ethanol mixtures has been determined at 25 degrees C. The generated solubility data sets have been used to assess the accuracy of different numerical analyses for the excess free energy model and a new numerical method for solubility prediction in water-ethanol mixtures based…
The Si L 2, 3 x-ray absorption near-edge structure (XANES) spectra of porous silicon nanomaterials and nanostructures with epitaxial silicon layers doped by erbium or containing germanium quantum dots are measured using synchrotron radiation for the first time. A model of photoluminescence in porous silicon is propose…
Polyaniline, polypyrrole, poly( N-ethyl aniline), poly( O-anisidine) and their composite coatings were electrodeposited on Al-2024 alloy. The electrodeposited films were characterised using IR spectroscopy. The peel test (ASTM 3359-97), the lap joint test (ASTM D1002) and electrochemical impedance spectroscopy were us…
Nous avons resolu la structure cristalline de l'analogue synthetique de la radtkeite, Hg 2 + 3S 2 ClI [monoclinique, groupe spatial C2/m, Z = 8, a 16.827(4), b 9.117(1); c 13.165(5) A, β 139.17(2)°, V 1543.2(7) A 3 ], par methodes directes, et nous l'avons affine jusqu'a un residu R de 5.27%, en utilisant 1498 reflexi…
Abstract The Markovian model of mixed-layering that has been used until now for the modeling of X-ray diffraction (XRD) patterns of 2:1 phyllosilicates describes the mixed-layer crystals as stacks of ‘layer units’ (LUs) that associate a 2:1 layer with an interlayer content. This model is not consistent when it is appl…
A mode of cracking termed Type IIIa has been found to occur in the welds of ½CrMoV pipework systems in the UK. This cracking mechanism is not as well documented as the more familiar Type IV cracking, which occurs on these and other ferritic steel systems, but is likely to increase in importance as plant ages. This pap…
Three effects of nano-particles on the toughness of nano-composite ceramics, namely, nano-particle clustering, crack pinning, and transgranular fracture, are identified from both the experimental and analytical studies. It is found that crack pinning toughens the nano-composite ceramics because a higher stress intensi…
Zinc phosphate and related compounds have achieved wide application as suitable replacements for toxic and pollutant zinc Chromates and lead oxides which were employed as anticorrosive pigments for paints. The behaviour of inorganic phosphates and tripolyphosphates may be improved by a suitable selection of complement…
Complex phase (CP) steels have very high ultimate tensile strengths, resulting from the use of specific alloying elements, which improve the hardenability but cause difficulties when applying a zinc coating by means of continuous hot‐dip galvanizing. The galvanizability of a cold rolled 1000MPa complex phase steel was…
Görgeyite, K 2 Ca 5 (SO 4 ) 6 ·H 2 O, is a very rare monoclinic double salt found in evaporites related to the slightly more common mineral syngenite. At 1 atmosphere with increasing external temperature from 25 to 150 °C, the following succession of minerals was formed: first gypsum and K 2 O, followed at 100 °C by g…
The stresses of laminate structures obtained by joining single layers of pure alumina (A), pure yttria‐stabilized tetragonal zirconia, 3Y‐TZP (Z), and an intimate mixture of alumina and zirconia (AZ) have been determined by fluorescence (in alumina) and Raman (in zirconia) piezospectroscopy. Three symmetrical stacking…
The formation of water-soluble coordination polymers was studied for a bifunctional monomer consisting of two terpyridin groups bridged by a poly(ethylene oxide) spacer. The complex formation between the terpyridin ligand groups and Cd 2+ ions was demonstrated using UV/vis spectroscopy and potentiometric titration. Vi…
Abstract Amorphous Se was converted into fibrous crystals of hexagonal Se or polyhedral crystals of α-monoclinic Se when exposed to organic fluids at room temperature for several days. The growth phase was dependent upon the dielectric constant of the organic liquids. It is notable that hexagonal Se and α-monoclinic S…
Abstract The properties of Si-associated goethite from sediments in the Atlantis II and Thetis Deeps in the Red Sea have been investigated in order to determine the effect of Si on the mineral. Two types of morphologies dominate in most samples: multi-domain crystallites, probably due to elevated Na concentration in t…
Abstract Summary: Dielectric cyclosiloxane bearing polysilsesquioxanes (CS‐PSSQs) were prepared by acid catalyzed polymerization using 2,4,6,8‐tetramethyl‐2,4,6,8‐tetra(trimethoxysilylethyl)cyclotetrasiloxane. The molecular weight, and content of the functional end‐groups of the CS‐PSSQs were found to be dependent on…