Materials Literature
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A fatigue cut growth evaluation for thermoplastic polyurethanes is pre sented. The results from an experimental design study that included four different polyol types, the effect of the molecular weight of the polyol and three different urethane contents are discussed. The polycarbonate polyol showed the lowest fatigu…
Computerized image analysis was used to obtain Fourier contour parameters and the fractal dimension of insulin zinc crystals (IZC). These methods are capable of characterizing and identifying small changes in the morphological and surface parameters of IZC with different crystal habits during dissolution. The Fourier…
Improved thermal stability of adhesion for an epoxy resin and a polyimide to copper has been achieved by pretreating the copper surface with polybenzimidazole solution. The adhesion strength for modified specimens was found to be twice of that for unmodified after aging at 250°C for 30 min. The coupling mechanism and…
Detailed two-dimensional plane strain analysis results for a reactor pressure vessel (RPV) with a shallow inner-surface axial flaw subject to a postulated pressurized thermal shock (PTS) transient are presented. The PTS transient simulates the pressure-fluid temperature history of an RPV in a pressurized water reactor…
The characteristics of rotary transformers can be successfully simulated by axisymmetric finite element analysis. Stator and rotor inductances, combinational inductances, leakage inductances, and coupling coefficients are calculated and compared with data measured from a commercial product. The calculated data are in…
Reaction of acetone oxime with [NBun4]4[α-Mo8O26] in refluxing methanol yielded [NBun4]2[Mo4O12(Me2CNO)2]1 while that with [MoO2(acac)2](acac = acetylacetonate) at room temperature resulted in the formation of [Mo4O10(OMe)4(Me2CNHO)2]2. The crystal structures of 1 and 2 have been determined [1, space group P, a= 9.009…
No presente estudo, foi avaliada a introdução de métodos de análises de micro-estrutura de fibras celulósicas. O algodão utilizado, proveniente das variedades IAC 17, IAC 19 e IAC 20, foi colhido em dez localidades do ensaio regional de variedades do Estado de São Paulo, no ano agrícola de 1985/86. Amostras de fibras…
The stress corrosion cracking (SCC) behavior of alloy 718 is known to be controlled by the microstructure of the material. By evaluating the SCC susceptibility of alloy 718 as a function of thermal treatment and by characterizing the microstructure produced during various thermal treatments, it has been possible to id…
The positive temperature coefficient of resistivity (PTCR) behavior of semiconductive BaTiO 3 is well explained by the Heywang model, which predicts the resistivity behavior above the Curie point based on the acceptor state density at the grain boundaries, the charge carrier density, and the energy gap, E s , between…
Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML ...Read More
The spectroscopic properties of octahedrally coordinated ${\mathrm{Ni}}^{2+}$ ions in ${\mathrm{Gd}}_{3}$${\mathrm{Ga}}_{5}$${\mathrm{O}}_{12}$ garnet are described with a five-parameter model in the framework of the adiabatic approximation. The effect of spin-orbit coupling on the vibronic potentials due to the fully…
Based on experience gained from processing samples from the Cenozoic basins of south-west Ecuador, a composite procedure for the processing of fossil diatoms from lithified or partially consolidated sediments is presented. The procedure is divided into four stages: (I) initial sample breakdown. (II) cemented rock brea…
The movement of dislocations in response to a finite-amplitude shear stress is treated as a quantum-mechanical process in which the dislocations tunnel through the lattice potential barriers and transit into adjacent potential wells. For simple potential barriers, the predicted dislocation velocity and macroscopic pla…
Highly-dense spherical particles of thorium-based oxides, ThO2 and (Th, U)O2, prepared by the sol-gel method were subjected to dissolution with nitric acid containing 0–0.05 mol/l NaF at high temperatures above 120°C. The dissolution rate depended upon temperature, fluoride concentration and UO2 content. High-temperat…
The new compound [VO(H2O)5][Cu2(bipym)2(H2O)(SO4)3]·7H2O 1(bipym = 2,2′-bipyrimidine) has been synthesised and its crystal structure determined by single-crystal X-ray diffraction [monoclinic, space group P21/c, a= 9.944(3), b= 13.928(6), c= 26.275(6)Å, β= 99.59(2)° and Z= 4]. Its structure consists of anionic alterna…
Abstract Accuracy, or how well a measurement conforms to the true value of a parameter, is important in XRD analyses in three primary areas, 1) 26 position or d-spacing; 2) peak shape; and 3) intensity. Instrumental factors affecting accuracy include zero-point, axial-divergence, and specimen- displacement errors, ste…
The effects of heat treatments of the industrial type: 8 h hold times at temperatures comprised between 600°C and lOOO’C, on the structural, mechanical and corrosion resistance characteristics of weld alloy 625 have been studied. During the heat treatments, the mean concentration ratios of Nb, MO, Si, Cr, Ni and Fe el…
The efficiency of additives against photoageing of poly(vinyl chloride) was evaluated by means of a combination of spectroscopic and chromatographic methods. IR and UV-VIS spectroscopy reveal the formation of chemical groups (such as carbonyl or polyene) that are characteristic products of the early stages of photodeg…
Thin-slice accelerated aging methodologies have not been ag gressively pursued because of concerns about the reliability and applicability of the results. The use of gases such as helium, nitrogen and carbon dioxide, which diffuse rapidly and are only sparingly soluble in the polymer, may be used to obtain a diffu sio…
A number of new DMIT derivatives have been synthesized and their structures have been determined. Among them only chiral BNPT-DTO has significant powder SHG efficiency which varies strongly with the crystal growth solvent and the crystalline temperature; this corresponds to its variability in molecular configuration.…