Mixing in processing of thermoplastics by extrusion

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 9–11, August, 1993.     

Spot welding of metal laminated composites

Composite materials of steel sheets joined by interlayers of zinc or lead- tin, show very good impact and corrosion resistance properties. Resistance spot-weld characteristics of these composite materials made of steel sheets and non-ferrous metals have been tested. Spot welds of composites with both zinc and lead- tin interlayers present good behaviour in peeling tests. Shear tests of the welds also show very high strength, probably as a consequence of simultaneous brazing because of the alloyed layer of non-ferrous material around the weld spot. This good welding behaviour enhances the possibilities of application of this composite.     

Interaction of an arbitrary force with a flexible punch or with an external circular crack

Two mathematically equivalent problems are solved exactly and in terms of elementary functions. An. external circular crack in a transversely isotropic elastic space is interacting with arbitrarily located point forces, applied in such a way, that the tangential displacements in the crack neck vanish. The problem of finding the tangential stress produced by such loading is solved exactly and in closed form. The second problem is that of interaction of an arbitrary point force inside the transversely isotropic elastic half-space and a flexible punch. The method of solution is based on the previously published results of the author. The results are of fundamental value, since they effectively give the Green's functions for solving any relevant problem of interaction.     

Determination of the length of deformation waves in the high-rate deformation of metals

A simple method has been devised for determining the length of a deformation wave in a solid. The method is based on the phenomenon of metalcutting and makes use of the interference of coherent waves. A hypothesis regarding the wave propagation of mechanical and thermal energy is proven experimentally, and it is established that the frequency of these oscillations increases with an increase in deformation rate.Translated from Problemy Prochnosti, No. 3, pp. 88–95, March, 1996.     

Calculation of an electric field in metal-insulator-metal structures

A method is proposed for calculating an electric field in a thin piezoelectric wafer taking into account the injection of electrons from a metal electrode into an insulator. The static current-voltage characteristic of a metal-insulator-metal structure is given, along with the results of a comparison of calculations and experiment. Translated from Izmeritel'naya Tekhnika, No. 1, pp. 46–48, January, 1996.     

Direct algorithms for data analysis in the location of sources of radiation from measured differences in distance: Model experiment

Results are presented from a model (numerical) experiment performed to check the efficiency of three groups of direct data-analysis algorithms to be used in satellite location of ground or ocean sources of radiation. The methodology behind the experiment is also explained. Translated from Izmeritel'naya Tekhnika, No. 12, pp. 40–44, December, 1996.     

A generalized model for the interaction between hydrogen and structural defects of the solid phase

A generalized mathematical model of the interaction between hydrogen and structural defects in metals is analyzed. The temporal dependence of hydrogen permeation flow is examined for three typical cases. The approximations to the general equation for hydrogen permeation flow obtained enable one to determine the interaction from experimental data. The extreme values of permeation flow are analyzed. A method for determining the kinetic parameters of interaction for a given permeation flow is suggested. The conclusion is made that, within the framework of the generalized model, it is possible to establish the mechanism of hydrogen trapping.Dnepropetrovsk Institute of Chemical Engineering, Dnepropetrovsk. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 29, No. 5, pp. 25–29, September–October, 1993.