Impact of phase composition on water adsorption on inorganic hybrids "salt/silica"

The effect of a "guest-host" interaction on the phase composition and sorption properties of the composite sorbents "salt in a porous host matrix" has been studied. The matrix was a mesoporous silica of KSK type, while the confined salts were CaCl(2), CuSO(4), MgSO(4), and Na(2)SO(4). Both structure and properties of the composites were studied by X-ray diffraction, titration in the pH range of 2-9, differential dissolution, and TG techniques. Chemical interaction between the silica surface and the salt during preparation results in the formation of the salt surface complexes and stabilization of the dispersed salt in two phases, namely, a crystalline phase and an X-ray amorphous phase. The water sorption properties of the composites depend on the phase composition and can be intently modified by using variation of the preparation conditions.     

Self-oscillations in an underexpanded jet flowing into a barrier

The distribution of the phases and amplitudes of the static pressure fluctuations with self-oscillations of an underexpanded jet flowing into a barrier is obtained experimentally in the present paper. The distribution of the Mach number in the compressed layer and in the subsonic flow in front of the barrier is shown. The results of the measurements of the characteristics of the self-oscillation process are discussed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 38–43, November–December, 1977.     

Dynamics of water vapor sorption in a CaCl2/Silica Gel/Binder bed: The effect of the bed pore structure

The dynamics of water vapor sorption in a compact, binder-containing bed of a CaCl₂-in-silica-gelpores sorbent has been investigated by NMR microscopy. The procedure suggested for the preparation of this bed allows the porous structure of the bed to be modified in a wide range. The bed pore structure and water transfer in the bed have been studied in relation to the particle size of the initial silica gel, the size of mesopores in the sorbent particles, and the binder content. By varying these parameters, it is possible to optimize the ratio of the diffusion resistance of the interparticle macropores to that of the internal mesopores of the particles. If sorption is controlled by water diffusion in the macropores, a sorption front forms in the sample to move inside the bed. The distance traveled by the front is proportional to the sorption time to the power 1/2. The effective diffusion coefficient of water in the macropores is estimated from the front motion dynamics to be between 0.8 × 10^?9 and 3.0 × 10^?9 m²/s, depending on the porous structure of the bed.     

Inverse feedback mechanism in self-oscillations in flow of an underexpanded supersonic jet against a planar obstacle

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 59–63, July–August, 1991.     

Influence of nonadsorbable component on the dynamics of water sorption on composite adsorbent

Experimental data are analyzed on water adsorption in the presence of a nonadsorbable component on the composite adsorbent silica gel impregnated with calcium chloride for different partial pressures of water and air. It is established that the mass-transfer mechanism inside the grain is Knudsen diffusion. It is shown that a dynamic structure is formed in the system, with increased concentration of the nonadsorbable component close to the external surface of the grain, causing externally diffusive resistance. The coefficients of heat exchange between the grain and the gas phase are defined.     

Effect of the face dimensions of a flat barrier on the self-oscillations generated in the interaction with a supersonic underexpanded jet

Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.6, pp. 164–168, November–December, 1992.     

Hartmann Effect. Region of Existence and Oscillation Frequencies

Data of experiments on determining the region of existence for autooscillations (Hartmann effect) with a frequency of approximately 450 Hz with variation in the distance from the nozzle to the resonator. Results of these experiments differ from the wellknown results of Hartmann and his followers obtained for shallow resonators. It is shown that the region of autooscillations exists for large distances between the nozzle and the resonator. The results obtained are explained using the modern knowledge of the gasdynamic structure of a supersonic underexpanded jet. It is shown that in determining the frequency of lowfrequency oscillations, it suffices to allow for the resonator length and its added mass.