Liquid and gas flows in porous media with allowance for induced anisotropy

The changes in the permeability of a porous medium resulting from the reorientation of the solid matrix particles under the influence of the percolating flow are considered. The mathematical model also contains the angular momentum equation, including the moment of the viscous flow forces. The state of the elastic matrix is characterized not only by the repacking strains but also by the particle orientation vector. The latter determines the anisotropy of the permeability tensor. The effective stress, strain, pore pressure and orientation vector fields in the neighborhood of an operating well are constructed. The effect of the induced permeability anisotropy on well productivity is noted.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.3, pp. 96–103, May–June, 1992.The authors are grateful to G. A. Zotov and V. A. Chernykh for their interest and support.     

Plug flow of a fibrous suspension

A model of a fibrous suspension with plug flow is constructed. A solution to the problem of the flow of a suspension in a straight round tube is obtained for two partial cases and is compared with experiment. With the flow of a fibrous suspension in a round tube, several sets of flow conditions can be distinguished [1–3]. If the flow rate is relatively small, the so-called plug flow is established. It is characterized by the fact that two flow regions are formed in the tube: the core of the flow, or the plug [1–3], in which the mass of the fibers is concentrated, and a layer near the wall in which only the liquid phase of the suspension flows. When the suspension has attained a determined velocity, the plug starts to break down, and the flow ceases to be of the plug type.Petrozavodsk. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 65–71, July–August, 1972.     

A search for radially excited charmonium states in experiments with low-energy antiproton beams

A spectrum of radially excited charmonium states is calculated for the model of relativistic spherically symmetric top for decay products. Within the integral formalism, the widths of these states are calculated for hadron resonance decay. Mass and width values obtained are in good agreement with the results of experiments. Six new radially excited charmonium states are predicted above the D-pair generation threshold equal to 3.73 GeV/s; three of them are experimentally confirmed. The possibility of application of antiproton beams with momentum from 1 to 15 GeV/s for charmonium spectroscopy is discussed, especially for masses exceeding the threshold of D-pair generation. The advantage of antiproton beams is that intensive generation of particle-antiparticle pairs is observed during antiproton-proton annihilation. This fact allows spectroscopic investigations to be performed with sufficient statistics and good accuracy. Therefore, masses and widths of scalar and vector charmonium states can be measured with high accuracy. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 66–73, December, 2007.     

Quantitative study of antioxidant properties of phenolcarboxylic acids from <Emphasis Type="Italic">Larix sibirica</Emphasis> bark

Antioxidant properties of caffeic, ferulic, vanillic, and 4-hydroxybenzoic acids isolated from Larix sibirica Ledeb. bark were studied using model radical-chain reactions for oxidation of propan-2-ol and 1,4-dioxane under kinetic control. Quantitative characteristics of the antioxidant activities were determined as effective rate constants fk_In for oxidation chain termination of the phenolcarboxylic acids. It was found that caffeic acid had the highest antioxidant activity among the investigated natural compounds. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 124–127, March–April, 2008.     

Optical interferometry in phase separated He---He mixture films

We report on interferometric studies of ³He---⁴He liquid mixtures. Anomalous wetting phenomena were observed in phase separated mixture films: the upper ³He-rich phase did not wet the lower ⁴He-rich phase under a small continuous feed of ⁴He atoms to the vapor phase. Instead, under this dynamic situation, floating pools of the ³He-rich phase were stabilized with a contact angle on the order of 10 mrad. In equilibrium, the concentrated ³He-rich phase was found to nucleate uniformly on the free surface, consistent with Antonow's rule.