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981.
V. Sh. Shagapov S. A. Lepikhin M. N. Galimzyanov 《Journal of Engineering Physics and Thermophysics》2007,80(6):1206-1209
A steady flow of a bubble gas-liquid mixture in a nozzle having a circular cross section has been investigated. The possibility
of realization of superhigh temperatures and pressures in the gas phase of the mixture in the region near the smallest cross
section of the nozzle has been analyzed. The influence of the initial radius of the flow and the volume content of bubbles,
determining the volumetric rate of flow of the liquid supplied to the nozzle, on the pattern of the flow has been considered.
__________
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 6, pp. 134–137, November–December, 2007. 相似文献
982.
V. P. Beskachko O. A. Golovnya A. E. Korenchenko 《Journal of Engineering Physics and Thermophysics》2007,80(1):132-135
The results of a numerical solution of the problem of vibrations of a torsion viscosimeter filled with an incompressible viscoplastic
liquid are presented. It has been shown that in the vicinity of the rotation axis there appears a dead zone, whose boundary
changes in the process of vibrations. The influence of plastic properties of the liquid on the characteristics of viscosimeter
vibrations has been determined. A method for identifying viscoplastic properties by the observed parameters of vibrations
is proposed.
__________
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 1, pp. 124–127, January–February, 2007. 相似文献
983.
É. M. Kartashov 《Journal of Engineering Physics and Thermophysics》2007,80(1):166-175
A number of problems concerning the Griffith criterion for brittle polymers have been considered. A general formula for the
energy of deformation of a stressed sample with surface and internal cracks has been derived. This energy was calculated simultaneously
for the plane and plane-deformed states of this sample. The commonly accepted view that the Griffith criterion determines
a quasi-safe stress that differs markedly from the athermal-fracture criterion was verified.
__________
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 1, pp. 156–165, January–February, 2007. 相似文献
984.
In wintertime, the use of studded tyres is common in the Nordic countries, steeply in creasing road wear. Apart from reducing surface quality and durability, the airborne dust presents a potential health hazard. To reduce road wear and dust release, there is a tendency to use harder and more wear-resistant aggregate materials.On the roads in and around Trondheim, mid-Norway, three types of aggregate material are common: greenstone, jasper and ‘mylonite’, in fact a cataclasite. Extensive laboratory testing suggests that cataclasite aggregate has better wear resistance than greenstone, but less than jasper [Erichsen E, Schiellerup H, Gautneb, H, Ottesen RT, Broekmans M. Road dust in Trondheim — analysis of the mineral content of airborne dust. (In Norwegian.) Geological Survey of Norway, NGU-report 2004. 037; 2004. p. 73]. However , observations on fluorescence-impregnated plane and thin sections demonstrate that in practice, cataclasite wears faster than greenstone, which may be attributed to its oriented fabric, as opposed to the random fabric in greenstone and jasper. The original article by Rosiwal from 1896 [Rosiwal A. Neue Untersuchungser gebnisse über die Härte von Mineralien und Gesteine. Verhandlungen der kaiserlich-königlichen geologischen Reichsanstalt, vol. 17/18; 1896. p. 475–491] on abrasion hardness and anisotropy provides an elegant explanation for the field observations. 相似文献
985.
M. V. Filipskii S. T. Surzhikov 《Journal of Engineering Physics and Thermophysics》2007,80(2):284-291
A method and results of numerical modeling of radiative heating of the back surface of the MSRO (Mars Sample Return Orbiter)
space vehicle of the European Space Agency are presented. To determine radiation heat fluxes, the method of discrete ordinates
on unstructured tetrahedral grids is used. The radiative model is based on the radiation-transfer equation in a multigroup
approximation. Numerical calculation has been performed for the most thermally stressed point of the assumed trajectory of
the entry of an MSRO-type space vehicle into the Mars atmosphere. A comparison with the discrete ordinates method on structured
grids is made. Good agreement between the results of calculations on structured and unstructured grids is demonstrated. The
level of radiation heat fluxes to the back surface of the MSRO space vehicle is predicted.
__________
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 71–78, March–April, 2007. 相似文献
986.
Analytical expressions for the shape of a charged drop of an incompressible liquid nonlinearly oscillating upon multimode
initial deformation have been obtained for the first time to within the third order of smallness. The second-order corrections
to oscillation frequencies are calculated depending on the spectrum of modes determining the initial deformation. The third-order
calculations show that the fundamental mode amplitude may increase due to the energy exchange with higher modes in a large
number of possible four-mode resonance interactions. 相似文献
987.
988.
Melissa Kurtz 《Journal of Failure Analysis and Prevention》2007,7(3):175-178
Fuel system assemblies used on recreational watercraft failed after a short time in service in a seawater environment. Examination
of the assemblies revealed significant degradation of the polyacetal connectors of the wire subassemblies. Optical and microscopic
evaluations indicated the complete loss of connector material implying decomposition of the resin, along with mud-cracking
and a rough surface morphology signifying chemical attack. An elemental analysis performed on both an intact connector and
degraded connector suggested a potential chemical agent in the form of zinc chloride. At elevated temperatures, concentrated
zinc chloride solutions are known to decompose polyacetal resins. The source of the zinc chloride was established as corrosion
products that resulted during the dezincification of the internal brass connector through exposure to saltwater in the application. 相似文献
989.
Sang C. Park 《The Visual computer》2003,19(1):38-49
A sweeping operation called polygonal extrusion is defined to improve the modeling power of CSG-based modeling. It is assumed that a 2D cross-sectional polygon (sweeping
polygon) moves in space while its containing plane is kept orthogonal to the tangent direction of the trajectory curve, a planar
polygonal chain having no self-intersections. The objective of the paper is to compute the boundary of the swept volume of
the sweeping polygon as a set of polygons (or triangles). The most significant challenge to accomplishing this objective is
the problem of trimming the swept volume. To solve the trimming problem, 2D-curve offsetting methods are employed. Two algorithms
are presented for polygonal extrusion that are based on different offsetting methods, the Voronoi diagram and PWID offset.
The proposed algorithms have been implemented and tested with various examples.
Published online: 28 January 2003 相似文献
990.
J. R. Díaz-Estrada E. Camps L. Escobar-Alarcón J. A. Ascencio 《Journal of Materials Science》2007,42(4):1360-1368
Deposition of Ti was carried out by laser ablation onto hydroxyapatite porous discs in an Ar atmosphere. Ti nanoparticles
were deposited onto HAp surface in order to modify its roughness and morphology as it is observed by scanning electron microscopy
(SEM) and scanning probe microscopy (SPM). A homogeneous distribution of Ti over the disc surface was corroborated by elemental
mapping. A comparison of the hydroxyapatite hardness before and after deposition was performed using SPM nanoindentation.
Transmission Electron Microscopy (TEM) showed that the Ti nanoparticles obtained were covered by an oxygen shell. It is shown
that surface modifications of the covered HAp by Ti result in better mechanical properties, reducing the possible damage to
the HAp ceramic by friction or impacts as it often happens in meniscus, bone junctions and the inclusion of prosthesis for
human treatments. 相似文献