Materials Literature
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We present the design and performance of a temperature- and pressure-controlled sample cell for the small-angle x-ray diffraction analysis of lyotropic liquid crystalline materials. The particular requirements for such a system of high resolution, high intensity, and control on sample homogeneity can be particularly w…
Abstract Thermal expansion coefficients were measured for a cancrinite from Bancroft, Ontario, Canada. Measurements of cell parameters and unit-cell volumes were obtained at room temperature and at heating intervals of 50°C over the temperature range from 50 to 1400°C. The unit-cell parameters for cancrinite increase…
The first stages of the electrochemical oxidation of Zircaloy‐4 are investigated using simple electrochemical tests and modeling the passive film modifications occurring as a result of contact with the electrolyte. Variations in electrode potential (open‐circuit conditions) or current density (potentiodynamic scans) c…
Abstract Differential scanning calorimetry (DSC) was used to investigate the crystallinity of crude PVC powders and annealed PVC compounds. Crude PVC powder exhibited a broad crystallite fusion endotherm ranged from 110°C to 220°C. High degree of polymerization of PVC showed high degree of crystallinity both for powde…
The aim of this work is to understand the molecular structural properties which may justify the great observed stability of doped alkoxy polythiophenes. Infrared frequency and intensity spectroscopy and Raman spectroscopy are used as probes. Suitably synthesized oligomers with increasing chain length and preassigned c…
Abstract The dielectric properties of hexagonal lithium iodate (α‐LiIO 3 ) single crystals have been studied at frequencies 10 −2 Hz⩽ v ⩽10 9 Hz and temperatures 100K ⩽ T ⩽ 500 K. Pure and iron doped crystals were investigated. Below approximately 10 kHz, the electric response of the LiIO 3 crystals is almost entirely…
A method is presented that positions polar hydrogen atoms in protein structures by optimizing the total hydrogen bond energy. For this goal, an empirical hydrogen bond force field was derived from small molecule crystal structures. Bifurcated hydrogen bonds are taken into account. The procedure also predicts ionizatio…
Abstract The magnetic properties of a valence delocalized mixed valent Fe(II)‐Fe(III) complex have been investigated. On the basis of magnetic susceptibility measurements and NIR absorption spectroscopy the double exchange parameter was determined to B = 940cm −1 while for the isotropic exchange interaction an antifer…
A Monte Carlo simulation of secondary electron emission from Be (atomic number Z =4), Mg ( Z =12), Al ( Z =13), Mo ( Z =42) and W ( Z =74) due to 100 eV–4 keV electron impacts is performed in order to understand the primary energy ( E p ) dependence of the yield and the energy distribution of secondary electrons. The…
A series of new poly(1, 3, 4-oxadiazole-amide)s have been synthesized by solution polycondensation of aromatic diamines containing preformed 1, 3, 4-oxadiazole rings with phenoxyterephthalic diacid chloride or by the reaction of the same diacid chloride with p-aminobenzhydrazide resulting in a polyhydrazide-amide whic…
The energy level schemes of the neodymium oxyhalides (NdOX, X = F, Cl, and Br) were studied and simulated with a phenomenological model accounting simultaneously for both the free ion interactions and the crystal fleld effect. The former included the electrostatic and interconfigurational interactions as well as the s…
Abstract PVC foamed building products have seen good growth lately because of their favorable properties and economics. Continued good growth is seen for the future. Expanding application areas, especially in the U.S. market, have created a need for knowledge on formulation and processin prarameters. Application areas…
Abstract Various size fractions of several samples of glauconitic clay and illite were heated stepwise under vacuum for extended periods to: 1) evaluate radiogenic-argon (Ar) yields in relation to composition and size range; and 2) investigate the kinetics of radiogenic-Ar release. Each sample was heated at 250, 375,…
Three POY yarns of 80/100, 80/48, and 80/34 denier/filament are textured with four variables at five levels. The Box-Hunter statistical experimental design is used to produce thirty-six samples in each case. The effects of texturing variables—draw ratio, disc surface speed to yam speed ratio ( D/Y ratio), first heater…
Abstract Formation of Fe-coatings or segregation at the expense of quartz grains is a common process in the tropical environment. Limited information is available about their internal structure at the submicroscopic level. The transmission electron microscope (TEM) and energy dispersive X-ray microprobe analyses (EDXR…
Abstract A novel heterogeneous polymerization process for synthesizing particulate with a wide range of properties has been developed. This process, which is called semi ‐ suspension polymerization (SSP), consists of two steps. In the first step a mixture of monomer, polymer, initiator, and other required ingredients…
Abstract The diprotonated, bishydroperchlorate forms of three isomeric β‐octaalkyl‐substituted tetrapyrrolic macro‐cycles, namely, etioporphyrin II (1) , etio porphycene (2) , and etiocorrphycene (3) , have been characterized both in chloroform solution, by UV/visible spectroscopy and 1 H and proton‐correlated 2D 15 N…
Crack faces in solids are modelled as non-standard patterns whose standard parts are self-affine fractals. The morphological and mechanical features of brittle and ductile fracture are discussed. A concept of equivalent traction is employed to obtain the asymptotic stress fields near the crack tip, which in turn used…
The use of natural zirconolites to assess the effect of α-decay damage and geochemical alteration on the release of actinides from HLW wasteforms is critically examined. There is evidence that the natural zirconolites provide a good chemical and radi-ation damage analogy for the HLW wasteforms, but additional work is…
Abstract Ammonia present in the product gas from coal gasification may increase NO x emissions from IGCC systems. A fixed bed reactor was used to study the effect of calcined limestone (CaO) on NH 3 decomposition and reaction of NH 3 and NO. Reactions at temperatures to 900°C in helium and in gas compositions typical…