Accelerated ‘relaxation’ or direct solution? Future prospects for fem

‘Dynamic’ or ‘viscous’ relaxation procedures have not gained much popularity in finite element analysis in which the direct (Gaussian elimination) solution dominates. Reasons for this are various—the most important being the rather slow convergence generally achieved for such procedures. However, it is possible to accelerate this quite dramatically and a method of doing so is shown in this paper. With the use of such acceleration and the inherent advantages of greatly reduced storage requirements and simplicity of programming, relaxation procedures promise an exciting possibility for the solution of large two- and three-dimensional problems in both linear and nonlinear ranges.     

Effect of HZSM zeolite in a catalyst on the indexes of hydroconversion of vacuum distillate

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 25–26, March, 1991.     

Esophageal stimulation by hydrochloric acid causes neurogenic inflammation in the airways in guinea pigs

To investigate whether tachykinins are released in the airways in response to stimulation of the esophagus, we studied the airway plasma extravasation induced by intraesophageal HCl in the presence or absence of neutral endopeptidase inhibitor phosphoramidon and NK1-receptor antagonist FK-888 in anesthetized guinea pigs. The airway plasma leakage was evaluated by measuring extravasated Evans blue dye in the animals pretreated with propranolol and atropine. Infusion of 1 N HCl into the esophagus significantly increased plasma extravasation in the trachea. Phosphoramidon significantly potentiated plasma extravasation in the trachea and main bronchi, whereas FK-888 significantly inhibited that extravasation in a dose-related manner. In the capsaicin-treated animals, airway plasma extravasation was completely inhibited even in the presence of phosphoramidon. Tracheal plasma extravasation potentiated by phosphoramidon was significantly inhibited in the bilateral vagotomized animals. These results suggest that 1) tachykinin-like substances are released to cause plasma extravasation in the airways as a result of intraesophageal HCl stimulation and 2) there are neural pathways communicating between the esophagus and airways, including the vagus nerve.     

Cementation of gold by magnesium in cyanide solutions

Contact deposition of gold by a magnesium powder in a hydrodynamic mode in 0.001–0.005 M solutions of the system [Au(CN)₂]^?-CN^? is investigated. It is found that the cementation rate of gold (V _c ) is directly proportional tot he concentration of the [Au(CN)₂]^? complex and the area of the cementing agent. As the temperature is increased in the ranges 20–30 and 30–40°C, the increase in V _c is 20–25 and 8–10%, respectively. The time dependence of degree of gold extraction on magnesium has an extreme character due to the increasing rate of the inverse process of leaching. In an ultrasonic field, the cementation rate and degree of gold extraction increase. This phenomenon is conditioned by destruction of the hydroxide film on the magnesium surface. The deposited gold has a film nature.     

Investigation and simulation of foam aluminum obtained from secondary aluminum raw materials by mechanical doping

The structure and phase composition of the samples of foam aluminum based on the AMg6 alloy (Al-6%Mg-0.7%Mn) obtained in a high-energy planetary mill are investigated. Mechanical doping provides high dispersity and homogeneity of all structural components including particles of the foam agent TiH₂, which allows one to obtain foam aluminum with a pore size of 1–5 mm at a density of 1.20–0.80 g/cm³. Mechanical properties of foam aluminum were estimated based on the results of compression tests. Based on preliminary investigations, an imitation model of foam formation is suggested that well describes the process of foam formation.     

Construction of the TUK-84 shipping assembly

The construction and basic technical characteristics of the TUK-84 assembly are described. The materials used to fabricate the vessel parts and sealing components are presented, and the composition and operation of the system which monitors the technical parameters are described. The construction of the rolled layers (courses) is discussed and their advantages are shown. __________ Translated from Atomnaya énergiya,Vol. 100, No. 6, pp. 419–422, June, 2006.     

Effect of the particle size ratio on the conductivity of conductor-insulator powder composites: Numerical simulation

A theoretical method for determining the percolation limit and effective conductivity of composites based on polydisperse mixtures of insulator and conductor powders is proposed. The effect of the particle size ratio between the insulator and conductor on the percolation limit and effective conductivity is studied. Numerical simulation of the microstructure, effective properties, and percolation limit in composites is discussed. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 31–40, 2007.     

Physicochemical materials research

For alloys in the range Os-OsAl₂-IrAl_2.7-Ir, as-cast and annealed at 1400 °C (Os-OsAl-IrAl-Ir) and 1250°C (OsAl-OsAl₂-IrAl_2.7-IrAl), phase equilibria are studied by powder x-ray diffraction (PXRD), differential thermal analysis (DTA), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX). Between isostructural aluminides OsAl and IrAl there exists a continuous solid solution (Os,Ir)Al. Other unary and binary phases form terminal solid solutions: (Os), (Ir), (OsAl₂), and (IrAl_2.7).     

Genotypic relationships among strains classified under the (Pasteurella) haemolytica-complex as indicated by ribotyping and multilocus enzyme electrophoresis

Two-hundred and one strains classified under the (Pasteurella) haemolytica-complex isolated from cattle, sheep, deer, pigs, hares and rabbits were investigated by ribotyping. Fifty-nine of these strains were selected for further studies using multilocus enzyme electrophoresis (MEE). A correlation between the clusters identified by ribotyping and MEE was demonstrated and the results furthermore indicated that a genetic basis exists for most clusters previously outlined by the use of quantitative evaluation of phenotypic data. The taxonomic relevance of ornithine decarboxylase and fermentation of L-arabinose, D-sorbitol and glucosides for taxonomic delineation within the (P.) haemolytica-complex was supported. A taxonomic importance was further indicated for ONPG, ONPX, ONPF, meso-inositol, D-xylose, maltose, dextrine and NPG in relation to some of the taxa. Within the porcine taxon 15, however, differences in ornithine decarboxylase did not correspond to genetic clusters. Six lineages were revealed by MEE. Lineage A contained electrophoretic types (ETs) representing biogroups 1, 3A-3H, 8A and 9, indicating a genetic relationship between these groups--an observation which was supported by ribotyping. Lineage B included biogroup 8D, 3 strains from biogroup 10 and a single strain from biogroup 1 and taxon 18/biovar 1. Lineage C contained strains allocated to biogroup 6 from ruminants and the porcine taxon 15. The similarity between these two groups was accentuated by ribotyping. Lineage D and the single isolate in lineage E contained strains allocated to biogroups 7, 10, 8B and 8C, in addition to single strains from biogroups 6 and 9. The same strains were found in the heterogenous ribotype cluster 17. Lineage F contained strains representing the leprine taxon 20 and the ruminant (P.) granulomatis. Ribotyping indicated that the ruminant biogroup 3J was affiliated with both taxon 20 and (P.) granulomatis.