# mass transfer

## Фрактальна модель тепло- та масоперенесення у капілярно-пористих матеріалах

Розглянуто фрактальну модель тепло- та масоперенесення у капілярно-пористих матеріалах, що описується системою диференціальних рівнянь у частинних похідних з дробовим порядком. Різницевим методом отримано числовий розв’язок задачі для різних значень дробової похідної.

There was considered fractal model of heat and mass transfer in capillary-porous materials which is described by the system of differential equations in partial derivatives with fractional order. The difference method receives the numerical decision of a problem at various orders of a fractional derivative.

## MHD Nanofluid boundary layer flow over a stretching sheet with viscous, ohmic dissipation

The objective of this research is to examine the steady incompressible two-dimensional hydromagnetic boundary layer flow of nanofluid passing through a stretched sheet in the influence of viscous and ohmic dissipations.  The present problem is obtained with the help of an analytical technique called DTM-Pade Approximation.  The mathematical modeling of the flow is considered in the form of the partial differential equation and is transformed into a differential equation through suitable similarity transformation.  The force of fixed parameters like thermophoresis number

## Kinetic Regularities and Mathematical Modelling of Potassium Chloride Dissolution

The dissolution process of potassium chloride particles in the apparatus with two-blade mechanical stirrer was investigated and the mass transfer coefficient was determined. The experimental results were generalized by criterion dependence. The independence of the mass transfer coefficient from the solid particles diameter was confirmed. A countercurrent process of potassium salt dissolution in two apparatuses with a mechanical stirring was considered. A mathematical model for countercurrent dissolution was developed and the efficiency of this process was determined.

## EVALUATION OF CONTRACTION STRESS IN CEMENT CONCRETE OF ROAD PAVEMENT

The mathematical solution for determining the contraction stresses in the cementconcrete or other cemented layers of road clothing is proposed in the article.

## Acid Hydrolysis and Ethanol Precipitation for Glucomannan Extraction from Crude Porang (Amorphophallus Oncophyllus) Tuber Flour

Extraction of glucomannan from crude porang flour by acid hydrolysis and ethanol precipitation was studied. Effects of acid concentration, temperatures and time were investigated, kinetics model of the process was developed and the parameters were evaluated based on experimental data. New data on yield and purity of glucomannan under various conditions were obtained.

## Методика розрахунку прямотечійного та протитечійного екстракторів для екстрагування цільових компонентів з шару пористих структур

This paper is devoted to the method of extraction unit calculation of periodical action for direct flow and return flow of extraction processes based on an analysis of the kinetics of extraction of components of the porous structures of minerals and seeds plant material under a constant driving force. Запропонована методика розрахунку прямотечійного та протитечійного екстракторів безперервної дії на основі аналізу кінетики екстрагування цільових компонентів з пористих структур мінеральної сировини та насіння рослинної сировини в умовах постійної рушійної сили.

## Modelling of Hydrocarbons Catalytic Conversion Process

A new experimental-computational method for designing the catalytic converters for gases purification contaminated with hydrocarbons based on researched mechanism of heterogeneous catalytic process which stages are described by mathematical models is developed.

## Development of Mathematical Models of External Mass Exchange under Conditions of Vibroextraction from Vegetable Raw Materials

We present results of development of mathematical models of external mass exchange in extraction of desired products from vegetable raw materials and mathematical models for the determination of the minimum time of achievement of the equilibrium state of the system and the current concentration of a soluble substance for their using in the optimization of operation of solid-phase extraction equipment.

## Mass Exchange of Dispersed Materials Encapsulating in Quasi-Liquefaction State

Experimental and analytical investigations of mass exchange during dispersed materials encapsulating in quasi-liquefaction state are presented. The mass transfer coefficients during encapsulating have been determined for different dispersed materials depending on air rate.