Vitebsk State  Technological University
  • Vitebsk, Vitebsk State Technological University, Belarus
Recent publications
A technology for producing sound-insulating materials from textile and light industry waste has been developed. Due to the unique arrangement of fibres and uniformity, the resulting material retains the shape and size of the formed plates during operation. The introduction of ground fabric edge waste and waste in the form of regenerated fibres into the composition of sample mixtures made it possible to increase their mass, density and rigidity. In order to increase the breaking strength along the materials length, it is proposed to laminate the developed samples.
The best parameters of knitted fabrics with combined electroconductive yarns for achieving the desired antistatic effect are determined. The results of investigation of the effect of electroconductive yarns on the physicomechanical and electrophysical properties of the fabrics are presented. The composition and choice of the type of knitting of the fabrics are described and the results of experimental investigation of the dependence of the density of fabric cells on their antistatic and shielding properties are presented.
The article is devoted to the development of a methodology for assessing the performance properties of composite textile materials for waterproof clothing. The existing normative and instrumental base for research of properties of materials for waterproof clothes is criticised, and a new methodological approach to the research and estimation of indicators determining the quality of waterproof clothes is substantiated. It consists in creation of such methods and means, which allow simulation of operating conditions for making a decision on suitability/unsuitability of a material for manufacturing clothes by a chosen method and for use in a designated field of application on the basis of results of comparative analysis of material properties be-fore and after such simulation. This approach is based on the analysis of manufacturing and operating con-ditions of a particular garment model. A concept, algorithm, methods and means of investigating the proper-ties of composite textile materials for waterproof clothing have been developed. The prospects of application of the developed methodology are outlined.
The functional properties of composite textile materials based on polyamide threads for shoes depending on the drying method are investigated. The drying and heat treatment of the material has carried out using hot air under stepwise heating from 120 to 180°C, as well as under microwave radiation at the generator power and frequency of 600 W and 2450 MHz, respectively. The experimental studies have revealed that using microwave heating improves the physical and mechanical properties at a lower concentration of water dispersion of the polymer binder and faster heat treatment.
The results of processing experimental data on heat treatment in drying processes of thin thermal insulation materials are presented. As a result of processing the experimental data by generalized complex variables, formulas for determining the heat flux density, average integral temperatures, the intensity of moisture evaporation, and the duration of the heat treatment process of materials were obtained. Based on the elements of the thermal regular regime theory, formulas for determining the rate of heating of the wet body and the rate of loss of moisture content have been established by processing experimental data using the least squares method. The conditions of the drying process in the regular mode are considered. Processing experimental data with generalized complex variables allows you to move from one coordinate system to another, from one variable to another, without performing additional time-consuming experiments. Based on the equation of drying kinetics and the generalized drying curve, the relationship between the dimensionless heat flux and the relative drying rate is given. For the single-zone method of calculating the drying rate curve, an approximate relationship for determining the relative drying rate is given. The relationship between material surface temperature and the relative drying rate in the heat treatment processes of ceramic tiles, asbestos sheets, wool felts was established. All of the above formulas were used to check the reliability of the obtained dependencies, as well as to compare the calculated values of the main parameters of the drying kinetics with the experiment.
The paper describes a technology for preparing a fibrous product for the formation of composite materials. The developed technology ensures maximum use of the strength characteristics of natural fibers in the formation of composite materials. The structure of a self-optimizing production system for the preparation of a fibrous product to form composite materials for various purposes is described.
Experimental samples of knitted goods from new promising types of polymer threads were produced and their properties were investigated. Warp knitted fabrics were chosen as the objects of the investigation. Different linear densities and numbers of filaments, out of which these fabrics are made, are a characteristic feature of these fabrics. Knitted fabric made from threads with maximum number of filaments has the minimum surface density, thickness, and air permeability. This makes it possible to reduce material content of the designed knitted goods with a set air permeability. Use of the obtained results is recommended for designing and manufacture of filter materials.
The results of the study of heat and mass transfer in the processes of heat treatment and drying processes of thermal insulating materials when the values of the Biot heat exchange criterion are less than one and the main factor is the interaction of the evaporation surface of the material with the environment (external problem) are presented. It was assumed that at low temperature gradients over the cross section of a wet body, thermal transfer of matter can be neglected, and phase transformations are absent (Posnov's criterion is equal to zero). By processing the experimental data on convective heat treatment of materials carried out by the least squares method, experimental equations for calculating the kinetics of drying have been obtained. Equations are given for determining the duration of drying, material temperature, heat flux density. On the basis of the theory of regular thermal regime, equations for the rate of heating of a solid and the rate of decrease in moisture content have been obtained. The verification of the reliability of the obtained equations and comparison of the calculated values of the parameters with the experimental ones are presented. An experimental dependence of the relative drying rate on the dimensionless moisture content has been established. The dependence of the generalized drying time on the relative moisture content is given. Also, based on the analysis of the experimental data on the thermal conductivity coefficients for wet thermal insulation materials, the dependences of the thermal conductivity coefficients on moisture content and temperature have been established. As a result of solving the criterion heat transfer equation, the values of the heat transfer coefficients for the period of the decreasing drying rate are obtained. The values of the Biot criterion in the processes of drying porous ceramics and asbestos are determined, too. It has been determined that the ratio of the moisture content loss rate to the drying rate in the first period does not depend on the drying mode and is a function of the initial moisture content.
“Mixed” calcium rare-earth aluminate laser host crystals Ca(Gd,Lu)AlO4 (CALGLO) with up to 10.8 at.% Lu codoped with Tm³⁺ and Ho³⁺ ions are grown by the Czochralski method along the [001] direction. The segregation of rare-earth ions is studied. The crystal structure is refined by the Rietveld method. Tm,Ho:Ca(Gd,Lu)AlO4 crystallizes in the tetragonal system (sp. gr. I4/mmm) exhibiting a K2NiF4 type structure. The lattice constants are a = 3.6585(6) Å and c = 11.9660(9) Å for a crystal with a composition of CaGd0.8947Lu0.0551Tm0.0448Ho0.0054AlO4. The stability of Ca(Gd,Lu)AlO4 solid-solutions is discussed. The polarized Raman spectra are measured, revealing a most intense mode at 311 cm⁻¹ and a maximum phonon frequency of ∼650 cm⁻¹. The polarized absorption spectra are measured. The transition intensities for the Ho³⁺ ion are analyzed using the modified Judd-Ofelt theory accounting for configuration interaction.
Formulation-technological options are offered for production of fiber-filled materials and products for shoe bottom based on use of production wastes. The technologies and the produced materials are analyzed and composition of the material for making shoe soles is determined. The properties of the produced soles are close to the properties of the products currently used in the shoe industry.
An account is given of the results of solving the differential equation of unsteady-state heat conduction with constant thermophysical coefficients for calculating the temperature of natural leather in the process of its drying, when pasted on a plate. A method for simplifying the solution of a nonlinear equation by the method of piecewise-stepwise approximation of transfer coefficients is considered. The possibility is shown for using the solutions of the equations of unsteady-state heat conduction for low-intensity processes of drying flat thin materials.
In this paper, a comparative analysis out of the physical and mechanical prop-erties of banana fiber produced in the Indian state of Tamil Nadu and properties ofscutched flax fiber produced in Belarus was carried out. The analysis is based onthe Big Data of the current quality control of long scutched flax fiber, accumulatedin the information quality control system of "Orsha Linen Mill".
The methods of approximation of the curve of the drying rate of fabrics according to the methods of A. V. Lykov and V. V. Krasnikov are described. The results of processing experimental data on convective tissue drying are presented. Equations are given for determining the drying time of fabrics, the density of heat flows and the temperature of fabrics during the drying process. The equations for determining the drying coefficient and the relative drying rate are given. An analytical method for determining the temperature for the period of falling drying rate is considered. The comparison of the temperature values according to the results of analytical solutions with the values obtained by the experimental formula is given. It is shown that the number of Bio during drying of fabrics is less than one, and the main limiting factor is the external heat and moisture exchange of the evaporation surface from the surface of the material with the environment. Verification of the reliability of the calculated values obtained with experimental ones is presented. The discrepancy between the values is within 5 % of the accuracy of the experiment and processing.
In modern conditions, the main goal of the organization activity is not only to obtain a commercial effect in the form of profit, but also its stable development, which depends on the health of people and the quality of the environment. Understanding this forms a new look at the organization only a moderate consumption of resources, the preservation of the natural environment for the sake of future generations can allow it to become effective in the long term. This requires a transition from the traditional economic understanding of efficiency to the socio-ecological and economic one, which is based on the balance of its aspects. The aim of the study is to develop the author’s definitions of the categories “socio-ecological and economic efficiency”, “balance”; as well as an assessment of the balance of aspects of efficiency based on the dynamic standard method. The objectives of the study include: a) to develop the author’s definitions of the categories of socio-ecological and economic efficiency and balance; b) consider approaches to assessing the balance at the micro and meso levels; c) form a system of indicators for assessing the effectiveness of the organization; d) develop a normative series of growth rates of performance indicators and compare with the actual one using the example of a particular organization. Materials and methods. In preparing the article, methodological approaches to assessing the balance at the micro and meso levels were studied, namely: the essence, content, statistical tools underlying them, their shortcomings and the ability to assess the balance of aspects of the effectiveness of the organization activity were identified. The assessment was carried out using the dynamic standard method, for which the normative order of subordination of the indicators included in it was determined. For the assessment, we used data from the industrial organization, the main activity of which is the production of outerwear (Republic of Belarus, Vitebsk region). Results. As a result of writing the paper, the author’s definitions of the studied categories were developed, a system of indicators for certain aspects of the effectiveness of the organization activity was formed, priorities in growth rates were determined and the normative ranks of the selected indicators were established. Based on the data of a specific organization, a comparison was made between the normative and actual modes of functioning based on the calculation of the Spearman’s rank correlation coefficient and Kendall’s rank correlation coefficient. The conclusion is made, theoretical directions of increasing the consistency of tempo characteristics are proposed. Conclusion. The article points out the degree of balance of certain aspects of efficiency (social, environmental and economic) on the example of a real business entity, which made it possible to form theoretical directions for eliminating their imbalance.
Subject of research: model of increasing the competitiveness of the national economy. The purpose of the study: develop a model for increasing the competitiveness of the national economy based on a neocluster approach. Research objectives: to develop the concept of a neocluster; to build a logical scheme for the formation of the competitiveness of the national economy on the basis of a neocluster approach. Methodology and research methods. General scientific and special methods of cognition: analysis and synthesis, induction and deduction, a systematic approach were used to conduct the research. A neocluster concept has been developed, which includes the concept of a neocluster, distinctive features, and a structural diagram of a neocluster. A model for increasing the competitiveness of the economy of a country / region has been built on the basis of a neocluster approach and a mechanism for increasing the country's competitiveness has been substantiated. The causal relationships between the sources of competitiveness are identified: (elements of Industry 4.0), directions and factors of increasing competitiveness. The developed theoretical foundations of the neocluster and the logical model for increasing the competitiveness of the national economy based on the neocluster approach can serve as a theoretical and methodological basis for the formation of a neocluster policy.
A transparent “mixed” 7 at.% Er:(Lu,Sc)2O3 sesquioxide ceramic was fabricated by hot isostatic pressing of commercial sesquioxide powders at 1750 °C/200 MPa in argon atmosphere. It exhibited a cubic bixbyite-type structure (a = 10.198 Å), a mean grain size of 5.7 μm and high low-signal transmission of 79.1% in the near-IR. The spectroscopic properties of Er³⁺ ions were studied. For the ⁴I11/2 → ⁴I13/2 transition, the stimulated-emission cross-section σSE is 1.30×10⁻²⁰ cm² at 2719 nm, the corresponding luminescence branching ratio B(JJ') is 19.9% and the radiative lifetime of the ⁴I11/2 state is 4.80 ms, as determined using a Judd-Ofelt theory accounting for intermediate configuration interaction. The crystal-field splitting of Er³⁺ multiplets was studied at 12 K. The ceramic exhibits a significant inhomogeneous broadening of spectral bands. An Er:(Lu,Sc)2O3 ceramic laser generated 342 mW at 2.71 and 2.85 μm with a high slope efficiency of 41.7% (exceeding the Stokes limit) and a laser threshold of 125 mW.
In the context of the world economy globalization, simultaneous increase in flexibility and volatility of the labour market, structural and demographic shifts, special attention should be paid to the employers' risk reduction associated with seasonal labour supply fluctuations. In the economic literature, the analysis of seasonality in the labor market is considered in terms of choosing the optimal time to apply for a job by job seekers However, the problem of optimal timing of recruitment by organizations remains poorly disclosed. The objective of this study is to forecast changes in labor supply at the labor market of Belarus, taking into account intra-annual seasonal fluctuations and occupation. In order to achieve the set goal the following tasks have been solved: search, analysis and selection of the sources of information about condition and dynamics of labour force supply in the labour market of Belarus; collection, purification, and analysis of statistical information about job seekers in Belarus; selection of the method for seasonal labour market analysis and construction of the seasonal wave, determination of the equations of trend; analysis of the obtained results. General scientific, economic method of analysis, method of grouping and graphical representations were used in the research. In the course of the research the authors built seasonal waves and obtained the equations of trends, which allow to make forecasts of labour force activity in the labour market of the Republic of Belarus in accordance with the type of activity. The research will allow the employers to: effectively develop the recruitment strategy; minimize the recruitment budget; choose the month when the job vacancy announcement will be submitted.
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31 members
Alexey A. Kornienko
  • Automation of technological processes and productions
D. B. Ryklin
  • Department of Textile Technology
Andrey Dyagilev
  • Department of Mathematics and Information Technologies
Alena Vankevich
  • vice-rector
S. V. Zhernosek
  • technology and equipment of machine-building production
Information
Address
72, Moskovski Ave, 210035, Vitebsk, Vitebsk State Technological University, Belarus
Head of institution
Andrey Kuznetsov Rector, Professor, Doctor of Technical Sciences
Website
http://vstu.by
Phone
+375 (212) 47-50-26
Fax
+375 (212) 47-74-01