Simulation of Extraction from a Capillary-Porous Particle with Bidisperse Structure

A mathematical model of extraction from a capillary-porous particle with bidisperse structure is described. Results of numerical simulations are presented together with the criterial equation for calculating the effective diffusion coefficient, obtained on processing these results. A criterion is established for selecting the optimal oscillation frequency. The criterion is tested on a physical model, with the obtained numerical results qualitatively confirmed.     

Formation of BiFeO<Subscript>3</Subscript> Nanoparticles Using Impinging Jets Microreactor

The influence of the reactants mixing in an impinging jets microreactor of the formation of singlephase nanocrystals of bismuth orthoferrite has been studied. The 30–100 nm amorphous particles are formed under the impinging jets microreactor conditions, which are converted in bismuth orthoferrite with mean crystallite size 17 nm at 420°С.     

Intensification of heterogeneous catalytic gas-fluid interactions in reactors with a multichannel monolithic catalyst

The review discusses the present-day state of research, industrial experience, and prospects for application of reactors with a multichannel catalyst for gas-fluid catalytic reactions.     

Hydrodynamics and mass exchange in gas-liquid slug flow in microchannels

The present state of hydrodynamics and mass transfer studies in segmented gas-liquid flow in microchannels has been analyzed. It has been shown that such parameters as gas bubble velocity, gas hold-up, relative gas bubble length, pressure drop, mass transfer coefficients from gas bubbles to liquid slugs and to liquid film, as well as mass transfer coefficient from liquid to channel wall can be satisfactorily predicted. Nevertheless, some correlations were obtained under definite conditions and should be summarized. The purpose of further research is to develop reliable methods for calculation of mass transfer coefficients as functions of channel geometry, phase properties, and phase velocities in mini- and microchannels.     

Modern state and perspectives of microtechnique application in chemical industry

A brief review of application of microtechnique, design and technologies of its manufacturing, methods of process intensification, and use for diagnostic purposes is presented. The main physical factors promoting heat- and mass-transfer intensification are described.     

On the evolution of invariant Riemannian metrics on one class of generalized Wallach spaces under the influence of the normalized Ricci flow

The paper is devoted to the study of the evolution of invariant Riemannian metrics on the special class of generalized Wallach spaces corresponding to the case of a₁ = a₂ = a₃ = 1/4. We prove that the normalized Ricci flow evolves all generic invariant Riemannian metrics into metrics with positive Ricci curvature.     

Synthesis of superparamagnetic GdFeO3 nanoparticles using a free impinging-jets microreactor

Russian Chemical Bulletin - Gadolinium orthoferrite GdFeO3 nanoparticles were synthesized by co-precipitation of gadolinium and iron(m) hydroxides in a free impinging-jets microreactor followed by...     

On the Ricci curvature of solvable metric lie algebras with two-step nilpotent derived algebras

We prove that the Ricci operator of any nonunimoular solvable metric Lie algebra having a two-step nilpotent derived Lie algebra of dimension 6 has at least two negative eigenvalues.