Numerical study of the transfer of shock-wave loading to a screened flat wall through a layer of a powdered medium and a subsequent air gap

The two-velocity, two-temperature model with two stresses in a mixture of a gas and solid particles contacting each other is used to numerically study the dynamic effect of an air shock wave incoming onto a solid wall with a screening layer of a porous powdered medium at some distance from the wall. The process is described for the case of one-dimensional planar motion of the gaseous and disperse phases under the assumption of a viscoelastic behavior of the powder skeleton. The effect of stepwise shock waves onto the porous powdered screen is considered. The influence of parameters of the screening layer and the air gap on the dynamics of loading of the screened solid wall is analyzed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 1, pp. 132–142, January–February, 2007.     

Solid-Fuel Combustion in the Sintering of Siderite Ore

Two technologies are considered for the preparation of solid fuel used in sintering: crushing with portions of roasted siderite ore whose strength is less than that of the fuel; or crushing of the fuel alone and subsequent mixing with the ore portions. On the basis of derivatographic data, kinetic equations are written for the high-temperature combustion of coke fines in a fuel–ore mixture obtained by the two methods. The most flammable fuel fraction in sintering is established. The results indicate that crushing of the fuel mixed with weaker additives is more effective in terms of decreasing the content of fines in the fuel and hence intensifying the combustion of large pieces.     

Modification of aluminum alloys in a solar furnace

The processes of the modification of the D16 aluminum alloy at the focus of a solar furnace are studied experimentally. The surface heat treatment at the solar furnace focus was performed without melting the surface. The experiment showed that the grain size decreases from 10 to 3 microns with the exposure of the specimens at the focal spot for 35 seconds, and small regions with the grain size 0.3 micron appear. Grains of dimension 0.3 micron are observed with the exposure of the specimen at the solar furnace focus for 40 seconds, and the microhardness is H _v = 74.8 kg/mm². The repeat measurement of the microhardness after 40 days corresponds to H _v = 104.8 kg/mm², i.e., the microhardness after modification in the solar furnace and natural aging increases by 16%.     

Spin Waves Interference under Excitation by Focusing Transducers: Logic and Signal Processing

Semiconductors - Micro-focused Brillouin–Mandelstam light scattering technique and micromagnetic simulations were used to study surface (SSW) and backward volume (BVSW) spin waves (SW)...     

Obtaining spherical powders of aluminomagnesia spinel using high-frequency heating in a cold crucible

Conclusions The method of direct induction heating in a cold crucible with periodic draining of part of the melt through a side aperture in the wall of the cold crucible, and spraying the jet with compressed air, can be used to obtain spherical powders of aluminomagnesia spinel suitable for plasma spraying of protective coatings.Translated from Ogneupory, No. 1, pp. 20–22, January, 1992.