It is proposed to refine the calculation of Nusselt numbers by considering the mass transfer coefficient in the evaporation zone, which is significantly larger than the molecular mass transfer coefficient of vapour. This refinement aims to address the discrepancy between the elevated Nusselt criteria observed during drying and the criteria determined by the thickness of the boundary layer, which provides more accurate results.
The process of mass transfer during the dissolution of boric acid spheres in water was investigated in the temperature range from 293 K to 323 K, and at stirring rotation rates from 1.67 to 6.67 s-1. The study aimed to determine the dependence of the dissolution rate on the stirring rotation rate and water temperature. The analysis of the experimentally obtained results revealed that the most significant factor affecting the intensification of the dissolution process is an increase in the solution temperature.
The sorption capacity of polymer blends was analyzed on the basis of absorption kinetics. The study was carried out in an adsorption-active medium with different degrees of deformation. Heptane and butanol were used as adsorption-active media. The influence of the chemical nature of the adsorbate on the sorption process was studied. The free volume fractions for each sample of the composition were calculated. The ability of materials to absorb different amounts of substances allows us to identify the behavior peculiarities of the interfacial regions of different chemical compositions.
This article presents the results of studies of the structure of the emulsion formed in the wastewater of edible oil production. The process of refining edible oils produces stable emulsions that are released into wastewater and pose a threat to the hydrosphere. The main pollutants in these wastewaters are organic substances, mainly of a fatty nature, which existing wastewater treatment plants are unable to treat to the level of sanitary requirements. This creates a significant environmental problem as it causes pollution of surface waters with organic substances.
Normal solutions of the Enskog–Vlasov–Landau kinetic equation were obtained within the model of positively and negatively charged solid spheres for the system ion solution – porous medium. The Chapman–Enskog method was applied. Analytical expressions for coefficients of viscosity, thermal conductivity, diffusion of ions in the system ionic solution – porous medium were derived by constructing the equations of hydrodynamics on the basis of normal solutions of the kinetic equation.
Modeling of the impurity diffusion process in a layer under the action of a system of random point sources is carried out. Mass sources of different power are uniformly distributed in a certain internal interval, that may also coincide with the entire region of the layer. The statistics of random sources is given. The solution of the initial-boundary value problem is found as the sum of the homogeneous problem solution and the convolution of the Green's function with the system of the random point sources. Averaging of the solution is performed on the internal subinterval and in the ent
In this paper, we suggest a diffusive and delayed IS-LM business cycle model with interest rate, general investment and money supply under homogeneous Neumann boundary conditions. The time delays are respectively incorporated into capital stock and gross product. We first demonstrate the model's sound mathematical and economic posing. By examining the corresponding characteristic equation, the local stability of the economic equilibrium and the existence of Hopf bifurcation are proved.
In this article, we study the global stability of fractional partial differential equations applied to the biological system modeling a viral infection. The reaction in the proposed biological system is described by the new generalized Hattaf fractional (GHF) derivative. However, the diffusion is modeled by the Laplacian operator.
The model of the impurity diffusion process in the layer where a system of random point mass sources acts, is proposed. Mass sources of various power are uniformly distributed in a certain internal interval of the body. Statistics of random sources are given. The solution of the initial-boundary value problem is constructed as a sum of the homogeneous problem solution and the convolution of the Green's function and the system of the random point mass sources. The solution is averaged over both certain internal subinterval and the entire body region. Simulation unit
The purpose of this research is to suggest and analyze a spatiotemporal of an IS-LM model with two delays, interest rate, liquidity preference and general investment function. The first delay into the proposed model refers to the time delay between the decision of investment and his implementation. However, the second one represents the delay in investment production. The well posedness of the model is proved. The stability analysis and the existence of Hopf bifurcation are obtained. Furthermore, numerical examples that confirm the analytical results are shown.