Scientific Journal of KubSAU

This article continues the works [1,2], devoted to the theoretical study of the basic laws of electroconvection caused by natural or artificial inhomogeneous conductivity of ion-exchange membranes in a smooth rectangular channel electrodialysis desalination unit. For this purpose, a mathematical model was created for a binary electrolyte electroconvection at overlimiting current modes in the form of a boundary value problem for a coupled system of the Nernst-Planck-Poisson and Navier-Stokes equations. We have studied the influence of heterogeneity on the ion-exchange membranes and ion transport electroconvection salt, calculated currentvoltage characteristic. The possibility of intensification of mass transfer due to the surface modification of ion exchange membranes was also shown

In this article, the author's approach for research of financial and economic crisis of the enterprises with use of canonical catastrophe of a fold and assemblage is offered. Mathematical models of development of crisis at the enterprise at different levels of detailed elaboration: 1) at an estimation of liquidity and solvency, financial stability, business activity, profitability; 2) at an estimation of the general financial and economic condition of the enterprise; 3) for construction of potential of development of enterprise are offered

In this article, a mathematical model of the dynamics of the efficiency of arbitration courts of Russian Federation in the form of the Cauchy problem for systems of difference and differential equations is built. The main regularities of the dynamics of the efficiency of arbitration courts are found

The article’s conclusion is that for adequate and effective inflation modeling in Russia by means of modern neuronet technologies it is necessary to consider tendencies of economic development. For training and forecast, it is necessary to use only those periods of time within the limits of which identical economic tendencies work. The article uses modern tool means, such as neuronet, which is offered to technology, for approximation and forecasting of rates of inflation

An analysis of the experimental data obtained by the authors, as well as reference books, allowed to hypothesize about the essential role of gravitational convection in electromembrane systems with ampholytes even in underlimiting current regimes. The article is devoted to the development of the mathematical model of ion transport in a flow elecrtomembrane system during electrodialysis of ampholyte-containing solutions with taking into account a possible appearance of gravitational convection, in particular, due to nonisothermal protonation–deprotonation reactions of ampholytes. The article presents the boundary value problem that is the new mathematical model for diffusion, convection and electromigration of four components of the solution (ions of sodium, dihydrogen phosphate and hydrogen, as well as molecules of orthophosphoric acid) in a half of an electrodialysis desalination channel, adjacent to an anion-exchange membrane. The membrane is considered as ideally selective and homogeneous. The system of partial differential equations, that is the base of the model, also includes equations of Navier-Stokes, material balance, convective heat conduction and the electroneutrality condition. The system of equations is supplemented by a number of natural and original boundary conditions. A distinctive feature of this study is the absence of assumptions about the equilibrium of chemical reactions in a diffusion layer. The results of the study can be used for the development of environmentally rational and resource saving membrane technologies for a processing of products of agro-industrial complex

The article is devoted to the numerical solution of boundary value problem of the binaryelectrolyte model of transport in membrane systems in the approximation of Ohm's law. Different numerical methods are offered. The main regularities of transfer are established

The phenomenon of electro convection in membrane systems is of considerable interest, because it is, according to many authors, the main mechanism of overlimiting mass transfer. A great number of theoretical and experimental works, in which, as a rule, dimensional values were used, are devoted to electro convection study. Because of that, in actual fact, there is investigated the influence of individual factors on the transfer process. For example, the influence of voltage jumps, the average speed of a forced stream of the solution, the geometric characteristics of the channel, the initial concentration, etc. However, the influence of these factors appears not separately, at the same time. Thus, there is the problem of introducing dimensionless complexes of dimensional values that have a physical meaning and that allow to evaluate the inner links of the process. As it is known, for solving that problem, there is applied a theory of similarity, based on the transition towards dimensionless parameters in equations and formulas describing the process, and using values, typical of the system under study. This work is devoted to the determining of physical meaning of similarity criteria of salt ions processes, taking into account electro convection in the desalting channel of electro dialysis apparatus. The channel is bounded with perfectly selective, homogeneous anion-exchange and cation-exchange membranes. The introduced similarity criteria are used so as to conduct the theoretical study of the effect of a number of parameters of a desalting process on electro convection

The article provides an overview of the basic rating methodologies, describes an algorithm of the own methodology for estimation the creditworthiness and investment attractiveness of the agricultural enterprises of Krasnodar region, using modern mathematical models. The rating of 30 agricultural enterprises of various patterns of ownership and scale is presented. The rating of 30 agricultural enterprises of various patterns of ownership and scale is presented

In the article, the reasons of occurrence and development of electro convection in electro membrane systems are analyzed. The basic rules of occurrence and development of process of electro convection in the channel desalination of electro dialysis apparatus are revealed

The review of the basic techniques of rating agencies of the Russian Federation and the algorithm of own technique of an estimation of credit status and investment appeal of regions Russian Federations with use of the device of the multivariate statistical analysis is described in this article