Vestnik of Vitebsk State Technological University

9-20

Authors: Aleksandr A. Struk, Alexander V. Medvedev, Konstantin E. Razumeev

The article presents the results of the study investigating the dependence of the density of silica nonwoven fibrous materials on the value of specific load. Nonwoven fibrous materials, in the form of mats, are extensively used across various industries. Among fiber materials, heat-insulating high-temperature silica materials hold a special place. The fibrous canvases are composed of silica fibers (KV-11) with a diameter of 7.5 microns and a length of 60 mm. Needle-punched mats are produced from a portion of these canvases using a needle-punching machine. Canvases produced by the mechanical method exhibit pronounced orientation of fibers. Consequently, samples of mats made from canvases with both longitudinal and longitudinal-transverse fiber orientations were prepared for experiments. The aim of the work is to investigate the dependence of the change in density of silica nonwoven fiber mats on the specific load. The experimental methodology was to determine the thickness of samples when loaded with weights. Needle-punched mats exhibit more stable parameters under compressive loads compared to mats made from mechanically formed canvases. Low initial density of needle-punched mats can lead to additional costs to achieve the specified values of heat shield density. The density of heat shields should be range between 100–200 kg/m3. From the available on the market fiber materials with the above parameters for the thermal screen needle-punching mats Supersilica with density ranging from 120 to 170 kg/m3 were selected. The conducted studies revealed that the correlation coefficient between specific load and thickness change, as a percentage of the initial thickness of the specimens, is higher for the specimens made from Supersilika mats. Therefore, the use of Supersilika needle-punched mats in thermal shields with double-sided silica fabric lining is more preferable.

35-43

Authors: Sergey A. Ignatyev, Valery I. Alshanski

Recent years have seen a growing demand from both researchers and industry for reliable models that can predict human thermophysiological responses. This article outlines scenarios concerning the impact of the environment on human thermal comfort, taking into account the properties of special protective clothing and the functioning of the human thermoregulation system. It provides the overview of the concept of thermal comfort and the thermoregulation system of the human body. The mathematical model should consider the complex behavior of thermophysical processes within the “person – clothing – environment” system. The heat flow between human skin and the inner surface of protective clothing is represented by a system of partial differential equations. The system is nonlinear due to the nature of human thermoregulation. The modeling encompasses both thermal and aerodynamic effects of the environment (such as temperature, air humidity, etc.), the thermal and moisture resistance of clothing, as well as heat and moisture flows to the surface of the human body resulting from internal thermoregulation. A particular challenge lies in the fact that all these processes must be modeled in an interconnected manner. Thus, the task is to move, based on mathematical models and a compartmental approach, to a quantitative assessment of the processes of mass transfer and heat of both individual parts and the human body as a whole. This problem is resolved in the work under consideration. Finite difference methods are applied to approximate spatial partial derivatives, which simplifies the problem to solving a system of nonlinear ordinary differential equations. To solve the problem, a high-precision approximation in the time dimension is used. The model is applied to predict the reaction of a clothed person to various changes in environmental conditions.

53-63

Authors: Nadezhda V. Tsobanova, Vilia D. Borozna, Alexander N. Burkin

Relevance. Footwear, a common consumer product, is subject to increasing demand for quality, comfort and safety. Children's footwear, in particular, requires careful attention as improperly selectin or poor-quality shoes can lead to abnormalities in the development of musculoskeletal system. According to TR TS 007/2011 "On the safety of products intended for children and adolescents" one of the safety requirements for footwear products is the design of the heel part of the shoe. One method to secure the heel part of the foot in shoes is the use of a rigid counter. Currently, the most popular materials frequently used for the frame parts in the footwear industry of Belarus are leather cardboard and thermoplastic materials (TPM). When using TPMs manufactured abroad, Belarusian footwear enterprises often follow manufacturer's recommendations, which are merely advisory. Consequently, the application of TPMs and their performance characteristics, which are almost unknown, has become a pertinent issue. This highlights the need to study the standard physical-mechanical and deformation-strength properties of advanced materials for shoe counters. The purpose of the study is to gather new information about the structure and physical-mechanical, deformation and strength properties of advanced TPMs used in the manufacture of footwear, including children's shoes. Research methods employed are standard methods of evaluation of physical-mechanical, strength and deformation properties for rigid artificial leathers. Results of work propose a list of indicators for assessing the physical-mechanical, strength and deformation properties of TPMs and methods of their evaluation.

71-81

Authors: Maxim V. Silibin, Vadim D. Zhivulko, Yuriy V. Radyush, Siarhei I. Latushka,Dmitry V. Zhaludkevich, Victor N. Shut,Andrei A. Kuzniatsou, Hanna S. Sokalava, Dmitry V. Karpinsky

Abstract The crystal structure of the solid solutions Bi0.65Ba0.35-zSrzFe0.65Ti0.35O3 within the dopant concentration range 0 ≤ z ≤ 0.35 was investigated based on the results of X-ray diffraction, infrared and Raman spectroscopy. The morphology and chemical composition of the solid solutions were studied using scanning electron microscopy and energy-dispersive X-ray spectroscopy. It is shown that all the studied compounds are characterized by high chemical homogeneity; an increase in the concentration of strontium ions leads to a decrease in the average crystallite size, while the morphology of crystallites remains practically unchanged. The obtained structural data allowed to estimate the changes in the crystal structure occurred within the region of the “rhombohedral-cubic” morphotropic phase boundary. The initial compound Bi0.65Ba0.35Fe0.65Ti0.35O3 is characterized by a two-phase structure, assuming a coexistence of the polar rhombohedral and cubic phases. Wherein the cubic phase is dominant in the initial compounds, and an increase in the concentration of Sr ions leads to the structural transition to the single-phase cubic state. An inhomogeneous structural state in the compounds under study has been determined to consist of the main matrix with paraelectric cubic structure, along with polar active nanometer-sized clusters having rhombohedral type of the unit cell. The presence of the nanosize polar clusters is confirmed by the results of dielectric measurements. The obtained data allowed to establish the evolution of the structural parameters during the phase transition from the rhombohedral to the cubic structure, as well as to determine the concentration region of the two-phase structural state and to specify the features of dielectric properties in the region of the morphotropic “rhombohedral-cubic” phase boundary.

93-104

Authors: Karina O. Buzhinskaya, Tatyana M. Borisova, Alexander N. Burkin

Recently, there has been an increase in the return of used shoes by consumers due to defects in the main insole. These defects include cracking, sagging, and breaks in the area where the molded sole grids are located. The shoe industry predominantly uses cardboard, an artificial material composed of glued short cellulose fibers, for the main insoles. The purpose of the work is to evaluate the effect of humidification on the properties of shoe cardboards and to verify the compliance of the quality assessment tests stipulated by the standards for insole cardboards with the actual operating conditions of shoes. Standard methods were employed to study the physical and mechanical properties of cardboard in a dry state and after exposure to water for 2 hours and 24 hours. Parameters such as moisture transfer and hygroscopicity, wetness, and changes in linear dimensions during moistening and drying were determined. An electron microscope was used to analyze the structure of the cardboards under study. The study indicates that the tests prescribed by the standards for assessing the quality of insole boards do not fully account for the real impacts on shoes during operation. Despite cardboard properties meeting the standards (with the exception of wetness), consumers report delamination and deformation of the main insole. Therefore, tt is necessary to develop new methods for assessing the quality of shoe cardboards that more closely resemble the operating conditions of shoes. It has been determined that during the moistening of cardboards, the adhesive bonds between the fiber and the impregnation weaken (Cellsan) or are partially destroyed (Flexan, Flexan 10, Texon, Konitex), which leads to a decrease in their strength characteristics. A high degree of wetness, coupled with a minimal moisture release, results in the destruction of cardboard. This is because everyday shoes are worn for extended periods throughout a day, and significant moisture accumulates in the cardboard from which the main insoles are made. A solution to this problem could be the development of a material for the main insoles that is more resistant to moisture and retains its strength when wet. Future research should assess the strength of shoeboards after repeated wetting and drying cycles. The results of this study are applicable to the shoe industry.

122-140

Authors: Iryna N. Kalinouskaya

The article presents the results of a study examining the digitalization processes of the human resource management system at the organizational level in the Vitebsk region. The relevance of research is proved by the rapid development of digital technologies, which have a significant impact on the field of human resource management. The objective of the research was to investigate the use of digital tools and the degree of automation of human resources functions in organizations within the Vitebsk region. This was done to ascertain the necessary competencies of human resource management specialists. The methodological basis of the study is based on a general scientific approach, employing methods of synthesis and comparative analysis. The information base of the study comprises materials obtained from a questionnaire survey conducted among heads of personnel services and directors of organizations in the Vitebsk region. The study determined that large private businesses in the region are leading digital transformation. The priority areas of automation include personnel accounting and administration, organization of staff training, evaluation and certification of employees. The demanded competencies of specialists in the field of human resource management include analytics, online training, and the use of VR/AR technologies. The data obtained reflect the regional specifics of digitalization of human resource management and can be used to develop measures for the development of human capital at the regional level. The scientific novelty of the research lies in the acquisition of new empirical data on the regional features of the digital transformation process within the human resource management system of organizations. This is crucial for development of measures aimed at enhancing human capital in the Vitebsk region. The practical results of the research make it possible to determine priorities in the introduction of digital technologies in the HR field for different types of organizations. The identified discrepancies between the available and desirable automation serve as the basis for the formation of plans and strategies for digital transformation by regional enterprises. Data on the necessary updating of HR specialists' competencies are useful for adjusting training and retraining programs by educational institutions, The results can be leveraged by IT companies to develop strategies for promoting HR automation technologies in organizations within the Vitebsk region.

158-174

Authors: Liubou V. Grintsevich, Lada M. Bullo

In today's economy, design is increasingly becoming a key factor in developing business models and launching innovative products to market. Design is relevant for both tangible and intangible products, serving as a means of communication between consumers and products. The scope of application of design is constantly expanding, and global trends in the implementation of design principles in enterprises show a positive impact on economic growth. The purpose of the research is to systematize knowledge about methods of implementation and commercialization of design innovations at enterprises and organizations in Belarus, with the goal to enhance the competitiveness of manufactured products. The article proves the influence of design on the competitiveness of products, the organization of processes and communications in enterprises. It provides an analysis of the types of design developments at the stages of the product life cycle and considers organizational options for integrating design into the design activities of enterprises. The importance of design in assessing the competitiveness of goods and services necessitates the consideration of intellectual property protection for design solutions. The article analyzes methods for protecting and transferring intellectual property rights, thereby expanding the possibilities of interaction between organizations and the design community. In conclusion, the article proposes measures that will contribute to the acceleration and development of design-related communications, the implementation of new design developments, and material and moral stimulation of the activities of designers.