Materials Literature
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We examine the influence of the diverging concentration fluctuations near a spinodal on the dynamics of branched polymer solutions in the vicinity of a sol−gel transition. Dynamic light scattering (DLS) measurements on pregel solutions and gels of methyl methacrylate (MMA) cross-linked with varying amounts of ethylene…
Abstract The absence of a predetermined helical sense in the polyisocyanates causes the formation of helix reversals which enforce a strong cooperativity for the amplification of chiral effects. The helix reversals though also place a limit on this amplification, a limit which would be eliminated by reducing the helix…
Evidence has been found that solid solution of 10 mol% lead titanate in lead magnesium niobate bears strong resemblance to spin and dipolar glasses. The frequency dispersion of the temperature of the permittivity maximum, Tm, has been analyzed using the Vogel-Fulcher relationship. The difference between the solid solu…
The thermal shock fracture mechanism of metal/ceramic functionally graded materials was studied by burner heating test. Dependence of thermal shock crack initiation and propagation on controlled compositional gradients was virtually shown and discussions were made on the basis of fracture mechanics with special refere…
Three homoleptic copper(II) complexes have been prepared which feature 6-halogen-substituted 2-pyridonate ligands [{Cu2(xhp)4}n](n= 1, xhp = 6-chloro- or 6-bromo-2-pyridonate; n= 2, xhp = 6-fluoro-2-pyridonate). X-ray structural analysis of the complexes showed that for the chlorine- and bromine-substituted derivative…
Polymerization of racemic α-methyl-β-propiolactone (MPL) was carried out using Zn-, Sn-, La-, Y-. and Al-based organometallic catalysts. It was found that Zn(C 2 H 5 ) 2 /H 2 O (1/0.6), ( n C 4 H 9 ) 2 Sn(OCH 3 ) 2, Al(O i C 3 H 7 ) 3, and (C 2 H 5 ) 2 AlOC 2 H 5 produced atactic poly(α-methyl-β-propiolactone) (PMPL),…
Abstract The phase separation states of hemicellulose and lignin in their blends were investigated by means of contact angle measurements. The hysteresis behavior in dynamic contact angles suggested that a phase separation of cluster‐state type (not of random dispersion type) took place at hemicellulose‐rich and ligni…
The miscibility of the carbosilane analogue of poly(α-methylstyrene), poly(methylphenylsilylenemethylene), named poly(sila-α-methylstyrene) (PSiαMS) with an M w value of 188 000 and polystyrene (PS) having different molecular weights is investigated using DSC and cloud point measurements. The observed miscibility beha…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Flash Point Value for n-Dodecane Based on the Manual Pensky−Martens Closed Cup Method (ASTM D-93)Janet M. Hughes, Dennis R. Hardy, and Erna J. BealView Author Information Geo-Centers, Inc., Indian Head Highway, Ft. Washington, Maryland 20744 Naval Research Laboratory…
The study of the photooxidation mechanism of crosslinked polyesters used for flat steel coating can be based on the analysis of photoproducts at the molecular scale: these photoproducts are formed in the matrix under exposure in an accelerated photoageing chamber SEPAP 12–24. Hydroxy functionalized aliphatic polyester…
Several thermoplastics and an epoxy were exposed to a variety of conditions to determine the effect of chemical environment on the materials. Weight gain measurements of the samples were made after exposure to low humidity, ambient air, 90/spl deg/C air, ambient transformer oil, and 90/spl deg/C transformer oil. Two m…
Summary The purpose of this study was to investigate effects of aluminium in the Zn coating on electrode life in welding galvanized steel sheet. Three hot‐dip galvanized and one electro‐galvanized steel sheet types were prepared for this study. Aluminium content in the coatings varied within the range 0.26–0.87 mass%…
A series of unsupported nickel–copper catalysts with various Ni/Cu ratios has been prepared by coprecipitation and characterized by thermomagnetometry, (TM), temperature programmed reduction (TPR) and oxidation (TPO) and scanning electron microscopy (SEM). It was found that the magnetization of the nickel–copper catal…
Structure and mechanical properties of the intermetallic compound NiMn alloyed by Ti and Al have been studied using optical and transmission electron microscopy, X-ray diffraction and dilatometry. Alloying has been found to reduce the temperature of β ↔ θ martensitic transformation, the martensite tetragonality and th…
The protonation of 2,3-dimethoxy-5-methyl-1,4-benzoquinone (UQ 0 ) has been determined to improve the quantum efficiency of charge separation between a zinc meso-tetra(4-sulfonatophenyl)porphine (MP) donor and UQ 0 (UQ 0 H + upon protonation) acceptor system. The primary effect of protonation is to increase the drivin…
The cyclo cocondensation of triethylenetetramine with arylpyruvaldehydes is templated by iron(III) chloride, to give a [12]aneN4 type diimine complex intermediate which may be reduced and demetallated in situ with sodium borohydride giving the saturated [12]aneN4 metal-free macrocycle in up to 60% overall yields; phot…
In the coordination field calculation of rare-earth ions, the D 2 point group basis functions were classified and labeled according to the relation of the point group chain R (3)* ⊃ O * ⊃ ⊃ The perturbation matrix elements of the coordination field for the rare-earth complexes in the dihedral field were systematically…
Tribological behavior was evaluated for polyolester base oil and the formulated oils in some HFCs and HCFC refrigerants environment. HFCs as well as R-22 showed the boundary lubricating effect depending upon the solubility of gas in the oil. Thus, higher gas pressure of the refrigerants improved the wear resistance. A…
The phase behavior of ( S )-ovalbumin in aqueous ethanol and (NH 4 ) 2 SO 4 solutions (pH 7.0) was investigated for temperatures ranging from 20 to 90 °C. The various morphologies observed were presented on ternary phase diagrams. At 20 °C, three morphologies were observed in aqueous ethanol: one-phase liquid, one-pha…
Effects of various boride former elements (Ta, W, Nb, Ti, Mo) and/or B on recovery and recrystallization of reverse-transformed austenite were examined in carbon-free Fe-19mass%Ni alloys. The combined addition of Nb and B was found to be the most effective in suppressing them; the recrystallization temperature of the…