Comparison of the Non-Interaction and Differential Schemes in predicting the Effective Elastic Properties of Fractured Media

The non-interaction approximation (NIA) formulated in compliances and the differential effective media (DEM) schemes are believed to be the most accurate theories for predicting the effective elasticity of fractured solids. While their predictions are always plausible, the DEM yields consistently softer effective properties than does the NIA. Here I compare these two theories with the finite element (FE) modeling for arrays of randomly located, parallel, penny-shaped cracks. I perform FE simulations by applying the homogeneous strain and homogeneous stress boundary conditions that establish the upper and lower bounds for the effective stiffness tensor. These numerically derived bounds demonstrate that the NIA is more accurate than the DEM.     

Effect of a number of sulfur-containing radioprotective agents on the evacuatory function of the stomach in mice

Tests staged on mongrel albino mice demonstrated that sulphur-containing radioprotectors used in doses two orders below those exercising a radioprotective action with their peroral administration are apt to significantly modify the evacuative function of the stomach. This properties of the sulphur-containing radioprotectors depends upon their chemical structure. A particularly strong influence on the evacuative function of the stomach in mice exerts cystamine dichlorohydrate, aminoalkylamino-alkylthiophosphates and mercaptoamidines. This property is less pronounced in cystaphos and cysteamine chlorhydrate. The least effect on the delayed evacuation was found in cysteamine bitartrate and in the disodium salt-4, 4(1)-trithiobis (butane-sulphonate). These data allow it to explain the specificity of the toxic and radioprotective action produced by diverse drugs with their peroral administration.     

High-speed shaping of a clad graphite powder

Conclusions High-speed shaping with single-ended load application enables parts of improved quality to be obtained from clad graphite granules. Within the working speed range investigated (from 0.3·10^–3 to 25 m/sec) the uniformity of density distribution over the compact height increases with increasing speed. Increasing the speed of loading in the high-speed working of clad graphite granules to more than 15 m/sec is not recommended because at these speeds the improvement in the uniformity of density distribution over the compact height is accompanied by the layering of the material.The work was carried out under the supervision of Professor V. G. Kononenko.Translated from Poroshkovaya Metallurgiya, No. 3(231), pp. 21–25, March, 1982.