The article presents a study of the kinetics of heat transfer using experimental data on the moisture exchange of thin flat ceramic, asbestos and felt wet plates based on the drying kinetics equation. The drying process was studied at a temperature of 90, 120, 150 degrees C and an air speed of 3, 5, 10 m/s. The relationships between moisture and heat exchange were established based on the drying kinetics equation, the Rehbinder number and the drying temperature coefficient. Based on the relative drying rate, equations for the heat flux density for the second drying period are established. Equations for the heat flux density for the second drying period based on the relative drying rate, equations for calculating average temperatures in the period of decreasing drying rate based on the drying temperature coefficient and the ratio of drying time by drying periods are determined. Relationships were established between complex variables, between the ratios of drying time by periods and the current moisture content to the critical one. It is demonstrated that cross-processing of experimental data on drying of specific materials allows to determine the critical moisture content of materials. A method for processing experimental data is presented for determining the critical moisture content of the material, experimental drying curves for ceramics, asbestos, and felt under different drying conditions. A formula is presented for determining the relative drying rate as a function of the ratio of the current moisture content to the critical one. The results of calculating heat flux densities, relative drying rates and average integral temperatures for the period of decreasing drying rate in the drying processes of ceramics, asbestos, and felt are presented, and a comparison of the calculated values with experimental data is provided. The error in the values lies within the error zone of the experimental data processing.
A passive device, the heat pipe has the capacity to transfer massive volumes of heat over small cross-sectional areas at extremely small temperature differentials heat pipes are extensively employed in many engineering applications owing to their exceptional efficiency in heat transfer, enabling the transmission of heat over considerable distances while minimizing temperature fluctuations. It is a heat transmission technique that is becoming more and more useful. The fundamental design of a heat pipe consists of an empty chamber placed after a cylinder or square filled with a vaporizable working fluid. This technique of heat transfer is used in solar water heaters, computers, solar power boards, laptops, mobile devices, and electronic circuits. Devices that require a large volume of heat transformations and heat management greatly benefit from the usage of heat pipes. This study investigates the influence of working fluid and pipe material on the performance of heat pipes. The researchers developed a complete experimental configuration to examine the performance attributes of heat pipes, encompassing thermal conductivity, heat transfer coefficient, and overall efficiency. The study examined a range of working fluids, including water, aceton, and ethnol, as well as different pipe materials such as copper, aluminium, and brass. The findings demonstrate notable disparities in performance indicators depending on the selection of the working fluid and pipe material. The entire heat transfer capability is significantly influenced by the thermal conductivity of the working fluid, whereby specific fluids demonstrate higher performance compared to others. The heat transfer efficiency is significantly influenced by the thermal conductivity and surface characteristics of the pipe material. Furthermore, the compatibility between the working fluid and pipe material significantly influences the long-term reliability and durability of heat pipes. Corrosion, material degradation, and phase change characteristics are critical factors that must be carefully considered when selecting the optimal combination of working fluid and pipe material. This study provides valuable insights into the design and optimization of heat pipes for various thermal management applications, highlighting the importance of selecting appropriate working fluids and pipe materials to enhance performance and reliability.
The relevance of research in the field of supply chain resilience has increased dramatically due to global crises such as the COVID-19 pandemic, geopolitical tensions and climate change. The article examines specific aspects of practical application of the methodology for quantitative assessment of the fault tolerance of supply chains, taking into account transport and logistics activities. A strategic adaptation model has been developed, which logically completes the development of a comprehensive QSCR methodology, transforming it from a passive analysis tool into an active tool for proactive management. It allows companies to quantify and compare various scenarios for the development of their supply chains; economically justify investments in improving reliability and digitalization; and move from a “firefighting” mode to systematic risk management, which is a factor in survival and competitiveness in the new economic reality. The implementation of this approach at the level of enterprises in the Republic of Belarus and the EAEU will improve the resilience of their business models, reduce their dependence on external shocks, and strengthen their position in regional and global value chains. Practical recommendations have been developed, grouped into three levels: corporate, industry (within the EAEU), and national.
The research results described in the article are devoted to issues of optimizing scheduled maintenance and necessary repairs of passenger cars. The paper assesses the availability of mobile infrastructure that can ensure timely and highquality repairs, enabling the efficient and effective use of motor vehicles for public needs. Currently, scheduled maintenance and repairs of vehicles are carried out at stationary stations, which requires time and material costs from owners. This article describes a study exploring the feasibility of using mobile service stations. It presents the results of the conducted assessment of demand for services and types of work required, as well as a market study of the use of such stations. The effective radius of the station's use is presented, its main capabilities and the target audience of clients who wish to service their cars at and use of mobile service stations as a means of improving the infrastructure for servicing passenger cars. This article provides a calculation of the expected costs of operating a mobile station, justifies the cost of work, and determines the minimum effective cost of calling a mobile technical service station. Practical recommendations are given for the effective use of a mobile service station for passenger cars.
A frequency-dependent ceramic material with high temperature stability of the resonant frequency has been obtained, which guarantees stable operation of devices based on it when temperatures change. The article presents the results of the influence of the production conditions on the microstructure and dielectric properties, as well as on the microwave parameters of ceramics. The solid-phase synthesis method was used to obtain the material. The synthesis was carried out at a temperature of 1000 degrees C for 2 h with subsequent thermal firing. It is shown that the optimal microwave properties of BaSm2Ti4O12 ceramics are obtained at sintering temperatures in the range of 1360-1380 degrees C. It is established that by changing the sintering temperature, the dielectric permeability of the ceramic material can be increased almost twice. The resonant frequencies of ceramics for various sintering temperature regimes were determined experimentally. The resonant frequencies of the materials range from 6.7 to 8.9 GHz. It is found that the quality factor of the ceramic material near the resonant frequencies significantly depends on the operating temperatures. At operating temperatures above 40 degrees C, a decrease in the quality factor of the ceramic material by 22-30 % is observed. By studying the frequency dependencies of the real and imaginary parts of the dielectric permittivity of the ceramics under study, possible polarization mechanisms were established. It is shown that the resonant nature of the dielectric permittivity dispersion is characteristic of the 100-900 MHz frequency range. At gigahertz frequencies, dipole and migration polarization prevail. Due to their properties in the gigahertz frequency range, the ceramics obtained can be used for the manufacture of substrates for microstrip antennas and microwave circuits, as well as for dielectric resonator antennas and components of satellite and mobile communication systems.
The Anti-lock Braking System (ABS) has become an essential safety feature in modern vehicles due to its capability to prevent wheel lock during braking, thereby preserving vehicle stability and steering controllability. As a typical mechatronic system, ABS integrates hydraulic, mechanical, and electronic subsystems governed by an electronic control unit (ECU). This study proposes a multidisciplinary co-simulation framework for investigating the braking performance of a passenger vehicle equipped with ABS. The hydraulic behavior of the system is modeled using AMESim Simcenter, while the vehicle longitudinal dynamics and control strategy are implemented in MATLAB Simulink. In the AMESim environment, a four-channel hydraulic ABS modulator is developed, where the ECU control signal serves as the input and the brake circuit pressure is generated as the output. This pressure signal is subsequently transmitted to the Simulink model, which utilizes it to evaluate wheel slip behavior under braking conditions at a specified tire-road adhesion coefficient, forming a closed-loop simulation architecture. To enhance braking efficiency under varying slip conditions, a hybrid control strategy combining a conventional PID controller with fuzzy logic is introduced. The proposed co-simulation structure enables real-time bidirectional interaction between the physical hydraulic subsystem and the control module: pressure outputs from AMESim are fed into Simulink, while control signals generated in Simulink are used to actuate the solenoid valves within the AMESim model. An experimental test rig was established to validate the proposed model and to assess the effectiveness of the control algorithm under real operating conditions. Experimental results demonstrate that the vehicle can decelerate from an initial speed of 90 km/h to a complete stop without wheel lock in approximately 2.54 seconds, corresponding to a braking distance of 30.48 meters. Compared with a conventional hydraulic ABS, the proposed control strategy reduces braking time and stopping distance by approximately 8.5 % and 6.5 %, respectively. Furthermore, a close agreement between simulation and experimental results is observed, with deviations of 4.4 % in braking time, less than 0.5 % in stopping distance, and 3.9 % in deceleration, confirming the accuracy and reliability of the developed model. The results indicate that the integration of PID control with fuzzy logic significantly enhances ABS performance, ensuring stable and effective braking under emergency conditions across varying road adhesion scenarios.
The article describes a method for calculating the composition of cement-based aerated concrete with a micro-aggregate made of granite rock for prefabricated and monolithic construction, including construction using 3D concreting technology. The method is designed for calculating the compositions of aerated concrete for thermal insulation and thermal insulation and structural purposes (in the range of axial compression strength classes: B0.5-B5, and average density grades D200-D900) using casting technology, with the aerated concrete mixture expanding in the cavities of molds, removable and non-removable formwork, including wall structures built using 3D concrete technology, without vibration. The developed and experimentally and productionally tested methodology is based on the use of fine-grained fractions extracted from granite screenings, a technological waste from the production of granite crushed stone at State Unitary Enterprise Granit in Mikashevichi. In the article, the proposed methodology is presented using the example of calculating the composition of structural and thermal insulation aerated concrete with a class of axial compression strength of B0.5 and a medium density of D400, in accordance with the provisions of STB [Standards of the Republic of Belarus] 1570-2005. The technique is an integral part of the author's development of an energy-saving technology for cellular cement aerated concrete without autoclave hardening, which makes it possible to eliminate energy-consuming, technically complex and expensive autoclave equipment in the manufacture of prefabricated products. Due to the possibility of hardening such aerated concrete in natural conditions, it ensures the use of heat-insulating aerated concrete obtained from it in monolithic construction, including heat and sound insulation of building walls, constructed using 3D concreting technology, as well as the installation of building structures in removable and non-removable formwork using aerated concrete for structural and thermal insulation purposes. The Belarusian National Technical University is ready to cooperate with interested enterprises and organizations in terms of using the article's material and in other areas of construction.
It is noted that in practice, the determination of the residual service life of units is performed either subjectively, or this indicator is not assessed at all due to the lack of necessary methods and means, while a large number of units are written off or sent for labor-intensive repairs with a significant portion of unused service life. The objective of this study was to develop a method for assessing the residual service life of an individual unit using the values of structural parameters associated with the measured diagnostic parameters by vibroacoustic methods, as well as assessing the total residual service life of a group of similar units. Based on the examination of a batch of engines, a method for assessing the residual service life of automotive units is proposed, which includes: the selection of the main structural parameter of the unit under study, of the probability density of its distribution, the total service life, the probability density of the distribution of the residual service life, and the total residual service life. It has been established that the probability density function of the total service life obeys the Weibull law, while the residual service life obeys the exponential law. It has been shown that the loss of the total service life of units before their decommissioning, write-off, or sending them for labor-intensive repairs amounts to 20-40% on an industry or enterprise scale. The obtained data allows us to provide an economic assessment of the conservation of the remaining service life of operating units. If repair work is scheduled using preliminary diagnostic studies, the range of replaceable parts included in connections whose condition is close to the ultimate limit will be determined.
In the context of increasing congestion on the road network of large cities, the most effective measure, according to domestic and foreign experts, is the development of urban passenger transport, and especially the creation of priority conditions for its movement. However, in today's conditions, it is quite difficult to assess the effectiveness of this measure, especially when the creation of a whole system of dedicated lanes is planned. Taking this into account, the purpose of this work is to develop methods for predicting the speed of urban passenger transport within the framework of creating priority conditions for traffic. To solve this problem, the author has reviewed existing methods and proposed his own methods. The first method for predicting message speed is based on analyzing the speed of passenger traffic during off-peak periods. Such a forecast can be carried out both by means of the counters located inside the rolling stock, and by means of the navigation systems installed inside the bus. The second method of forecasting is based on the data of the geoinformation system "Yandex traffic jams". The essence of the method is to obtain data on the speed of the traffic flow on the network and its recalculation for bus traffic, taking into account the time losses at stopping points. The results of the study showed that the implementation of measures to allocate separate lanes for passenger transport in the city of Yekaterinburg will allow to increase the average speed of urban passenger transport on the network during peak hours by 27 %. At the same time, the average travel time of a passenger during peak hours will decrease by 35 %. The results obtained can be used in cities of various sizes, and it is especially effective to apply such methods when developing transport planning documents, such as the "& Scy;omprehensive Traffic Management Scheme" and "Comprehensive Transport Scheme".
A solution for optimizing a rectangular reinforced concrete slab with a rib-reinforced technological opening is proposed. The static analysis was performed using the Sturm computer program, written in the Pascal (Delphi) algorithmic language. This article presents an effective method for parametric optimization using a 2D elastoplastic finite element model. The load is applied to the finite element model through the nodes connecting the elements. Considering the properties of concrete, a nonlinear constitutive law for the deformation of finite elements with changing stiffness before and after crack formation was adopted. Accordingly, the Seidel approximation method is used to determine the stress-strain state of the slab. The cost of concrete and reinforcement used in manufacturing the slab is taken as the objective function. The solution is constrained by the slab thickness, rib height, maximum deflection, stress, and bending moment. The optimal solution is determined in a discrete space constructed on the optimization variables: slab thickness, rib height, and reinforcement area. Initially, based on scanning results on a grid of a selected individual layer, built on the hpl and hreb parameters, a “forbidden” region of the space constrained by the limits is established. The search for the optimal solution is performed on the “permitted” part of the space. Then the next subsequent layer is considered, and the optimal solution is likewise determined within it. The process continues until all layers of the search space have been examined. The global minimum of the objective function is selected from all found solutions. This method guarantees that the found solution is absolute.
The article examines the problematic issues of the existing methodology for evaluating the effectiveness of the implementation of scientific and technology policy (STP) of the Republic of Belarus, particularly regarding indicators reflecting the degree of technological independence of the state (technological sovereignty). It is concluded that the current approaches and the system of STP evaluation indicators do not align with state leadership requirements for ensuring technological sovereignty and require adjustment and modernization. The author has conducted a comparative analysis of international experience and approaches to STP evaluation in the context of the technological sovereignty across OECD countries, the EU, China, and Russia, identifying potential areas for methodological adaptation applicable to Belarusian conditions. A proprietary methodology for quantitative and qualitative assessment of technological sovereignty is proposed, based on an integral index of effectiveness of scientific and technology policy. This methodology accounts for the specificities of Belarus, the Union State framework, and prioritizes the security of technological chains in key economic sectors. The expected motivational impact of the new indicator system on scientific development, business attraction, and human capital enhancement is substantiated.
Supply chain management (SCM) has its own characteristics depending on its type, the process entities involved in the chain, external and other factors. Supply chain management in transport requires special attention due to the high degree of mobility, dynamics, routing, the need for synchronization and multimodality, geographical and geopolitical factors and, in essence, complexity. This approach makes management flexible (Agile SCM is a flexible supply chain or a more dynamic type of management that quickly responds to changes in demand and external factors, using the principles of flexibility, adaptability and short iterations). The article examines issues of digitalization and supply chain management, taking into account transport and logistics activities. The uniqueness of supply chain management in transport is highlighted, the connecting role of transport in supply chains of different types is shown, and their possible subjects are described. A multi-criteria classification of modifications of transport-oriented supply chains has been developed based on six criteria (geographical coverage, structural complexity, level of digitalization, management strategy, mode of transport, type of freight flow), including 20 typical modifications with a detailed description of their features, advantages, disadvantages and the role of transport. The proposed classification is the basis for developing differentiated management strategies aimed at increasing the resilience and efficiency of supply chains. The novelty of this approach lies in the systematization of supply chains, which allows for their comprehensive diagnosis, more accurate identification of risks, and the determination of adequate management and digital transformation strategies for each specific modification. For the first time, the level of digitalization has been identified as an independent classification criterion, reflecting current trends in the digital transformation of the industry. Digital transformation is shown to be a two-pronged factor: it improves operational efficiency and acts as a key tool for ensuring resilience through end-to-end real-time visibility, predictive risk analysis, and flexible reconfiguration of logistics processes in the event of disruptions.
The objective of this study is to establish the force range of applicability of the Hertz's contact theory in the mechanics of dense sandy soils by developing and testing a methodology for calculating the microcontact strength of mineral particles. A force analysis of the elastic contact of soil particles within a unit cell modeled by microspheres with a diameter equal to the average diameter of particles of the fractional composition under consideration was performed. The particle packing in the unit cell was assumed to be a body-centered cube. The frictional interaction between the particles was described by the Amontons-Coulomb friction law. Contact interaction parameters were determined using Hertz formulas, taking into account the difference in the mechanical properties of the surface layer from similar indicators of standard samples. A model for converting loads in a single cell to the nominal pressure on the soil mass is proposed. The calculated force acting on a particle was determined as the product of the nominal pressure in the particle mass and the cross-sectional area of the unit cell. Analytical relationships are provided for calculating the forces arising in the particle contact zone, as well as the maximum pressures at the contact areas. An assessment was made of the external pressures on the soil mass at which the equivalent microcontact pressures, calculated using the second theory of strength, reach the compressive strength limit of the material of the surface layer of mineral particles. It is proposed to consider these pressures as a limitation on the applicability of Hertz's theory to solving contact problems in sandy soils. The research results can be used in educational programs for training specialists in construction and chemical engineering specialties, as well as in scientific research practice.
The paper presents the equipment of an installation for restoring the productivity of water intake wells through longitudinal circulation-reagent treatment of the filter and the filter-adjacent zone. The equipment includes a reagent tank, a diaphragm pump placed above the water level in the well, a pipeline system, and a resistance element placed with an annular gap inside the filter being cleaned, ensuring uniform filter declogging along its entire length. The treatment technological process is described, which involves the continuous circulation of the reagent by the pump in the annular channel formed by the inner impermeable walls of the corrugated element and the outer permeable walls of the filter. Through the filter's openings, the reagent penetrates into the filter-surrounding zone and ensures uniform decolmatation of the gravel pack. The key advantages of the proposed solution are substantiated: increased efficiency of filter and filter-surrounding zone decolmatation, reduced energy consumption, and the ability to use a wide range of reagents, including sodium dithionite. Furthermore, the proposed solution reduces the labor intensity of technological operations performed by personnel when treating wells with decreased flow rates. Calculated flow schemes for two operational modes of the equipment are provided: 1) continuous reagent circulation in the system "diaphragm pump-injection pipeline-well filter-suction pipeline-diaphragm pump"; 2) pum-ping of the waste solution from the well into the tank. For these modes, equations of motion for the reagent and reaction products were compiled and solved using a graphoanalytical method. The presented hydraulic calculation methodology allows to obtain values of circulation flow rate and flushing velocity depending on the static water level in the well, the geometric dimensions of the filter and pipelines, and to select the necessary technological equipment. An example of calculation is given.
The article presents the results of experimental and production studies dedicated to investigating the influence of the surface quality of metal products cleaned using hydro-abrasive technology (based on the use of bentonite clay in a water jet) on the laser cutting speed. To analyze the impact of various hydro-abrasive treatment (HAT) parameters on the efficiency of laser cutting of metal surfaces, production tests were carried out. During these tests, three groups of samples made of St10 structural steel, with dimensions of 200x200 mm and thicknesses ranging from 2 to 12 mm, were used. The choice of this steel grade is due to its widespread use in mechanical engineering for making machines, mechanisms, and welded structures, along with its excellent combination of high strength characteristics with a relatively low cost. The use of bentonite clay with a concentration of K-b = 2-3 % in the working jet leads to an increase in the force impact and the formation of a film coating on the cleaned part; soda ash with a concentration of K-k s = 2-3 % allows the working solution to be kept in suspension; carbon black with a concentration of K-szh= 11-13 % promotes the formation of a film coating with high light-absorbing properties; water eliminates dust formation in the processing zone. The presented study confirms that the HAT method is effective (compared to shot blasting) for increasing the productivity of the laser cutting process (St10) by 15-20 %. The implementation of a modernized technological process based on the use of hydro-abrasive treatment (HAT) instead of traditional shot blasting allows for the complete elimination of the operation previously intended for removing burrs from the part surface. The absence of burrs, along with the increased speed of laser cutting, is directly due to the preliminary processing of the workpiece (in the form of a protective casing) using HAT method, implemented with an innovative patented composition.
The subject of the research is the assessment of the prospects for introducing blockchain technology in the processes of verification of academic achievements and electronic document books, electronic diplomas, grade registers) in the educational process of the Belarusian State University of Informatics and Radioelectronics. The purpose of the article is to empirically assess how students perceive and are prepared to use blockchain services, as well as to identify which factors statistically significantly influence their satisfaction with the educational process using factor, regression and correlation analyses. The study is based on survey data from 200 students, considered as the main group of consumers of the university's digital services; the obtained results are interpreted taking into account the limitations of the sample and the need for subsequent extension of the research to administrative and IT personnel. Data analysis was carried out using Python language libraries. The main aspects of the use of blockchain technology, its impact on student satisfaction and the effectiveness of educational programs are considered. The use of blockchain technology in the university's educational process has significant potential to improve learning efficiency. The analysis of factor loadings showed that the key variables influencing the perception of blockchain technology are "Data Security", "Data Transparency" and "Trust in Technology". Regression analysis showed that "Data Security" and "Data Transparency" have a statistically significant impact on student satisfaction with the educational process, while trust in blockchain technology demonstrates borderline significance. The analysis of the correlation matrix showed that all the variables under study-"Level of Knowledge", "Availability and Reliability of Information", "Trust in Technology" - have a moderate or strong positive correlation with student satisfaction. It is recommended to increase the number of hours allocated to the study of blockchain technology and to conduct regular training sessions for teachers.
High-strength steels are increasingly used to manufacture welded structures in various industries, significantly im-proving the performance characteristics of products. These strength properties can be achieved through specialized alloying systems, thermomechanical processing, and other methods. The higher the strength and the more complex the strengthening system, the less its technological weldability. Currently, high-strength thermomechanically strengthened steel is increasingly used for the manufacture of welded structures. It offers the required armor resistance at relatively thin sheet thicknesses, but at the same time, it is highly susceptible to cracking in the near-weld zone. Cracks form immediately after welding, as well as over time during operation and external loads. The main cause of their formation is high level of internal stress and hardness values near the fusion line in the base metal, caused by the influence of the thermal cycle of welding. This article, based on the results of experimental studies and mechanical tests of welded joints made of high-strength armor-resistant steel 37Y, propo-ses a heat treatment option to reduce the hardness in the heat-affected zone near the fusion line, which significantly reduces the likelihood of crack formation. The essence of the proposed solution consists of heating the heat-affected zone of a welded joint made by consumable electrode arc welding (MIG) in a protective gas environment of 98 % Ar + 2 % O-2 using an auste-nitic welding wire 03-08X20H101-7T, through the deposited weld metal using non-consumable tungsten electrode (TIG) welding technology. Local heating of the weld beads is carried out until a liquid pool mirror appears, and all welded joints are processed by rectilinear movement along the axis of the weld. The features of hardness distribution in the heat-affected zone of welded joints made of high-strength steels and the nature of the effect of local heating on them are studied.
A numerical solution is proposed for a contact problem for a stamp located on an elastic foundation in the form of a half-plane with a broken shape. Contact stresses are determined using B. N. Zhemochkin's method. However, the coefficients of the force method in the resolving equations of the mixed method are determined using a variational-difference method. For this purpose, the computational domain of the elastic foundation is divided into rectangular cells of varying areas and the strain energy is determined for each cell. The functional of the total energy of the elastic foundation and the applied external load is obtained by summing the strain energies of each cell and the work of external forces and is a quadratic function of the nodal displacements of the computational domain of the elastic foundation. Differentiating the total energy functional with respect to each nodal displacement allows us to form a system of linear algebraic equations whose solutions are the nodal displacements. To form the displacement matrix of the section centers using B. N. Zhemochkin's method, the external unit load was specified as two forces applied to the boundary of each section. This allowed us to obtain a matrix symmetrical with respect to the main diagonal in the equations of the mixed method of forces. Thus, a system of equations was formed for the method of B. N. Zhemochkin for calculating a stamp applied to the boundary of a half-plane during its translational movement. After solving the system of equations of B. N. Zhemochkin's method, the forces in the contact constraints between the stamp and the elastic foundation and the linear displacement of the stamp, were found. This allowed us to determine the distribution of contact stresses and the position of the external force causing the translational movement of the stamp.
The installation of a vertical barrier in the path of surface wave propagation in soil, in the form of an open trench or a trench filled with various materials is considered an effective method of vibration isolation against explosive, seismic, industrial, and transportation-induced vibrational impacts. In this work, based on the finite element method, numerical modeling of dynamic wave propagation in soil with a vertical wave barrier in their path was performed. The soil medium was considered as a spatial elastic inertial array with a specified damping of oscillations according to Rayleigh theory, limited by non-reflective boundaries. The dynamic load was applied in the form of a sinusoid. The change in surface vibration parameters behind the barrier was studied depending on the material of the latter. The calculation results are presented in dimensionless quantities for the geometric parameters of the barrier and its dynamic properties. It has been found that the main parameter of the barrier material determining the effectiveness of vibration isolation is the dynamic modulus of elasticity of the barrier material. Its increase or decrease in relation to the elastic modulus of the soil leads to a reduction in vibrations behind the barrier in the direction of propagation of dynamic waves in the soil. Formulas have been obtained describing the relative reduction of soil vibrations behind the barrier depending on the coefficient of relative reduction in the dynamic modulus of elasticity of the barrier material. The most effective option is a composite structure consisting of alternating layers of materials with the highest and lowest dynamic moduli of elasticity relative to the surrounding soil. The reduction of vibration amplitudes in the soil behind the barrier for this composite structure reaches 87.7 % at a barrier depth equal to the Rayleigh wave length.
One of the key operating bands for wireless communication is the VHF (Very High Frequency) band. This band accommodates a variety of applications within its operational frequency range, such as Land Mobile, FM/TV Broadcast, amateur radio etc. Consequently, it is essential to explore Antenna designs that are suitable for this band. This paper concentrates on the dipole folded antenna design at 100 MHz frequency. Simulations, fabrication, and testing have been conducted. This paper presents a novel model, along with the implementation of a folded dipole antenna optimized for military vehicular applications in the VHF band (30-300 MHz). The proposed antenna achieved a measured resonant frequency of 98 MHz, a return loss of-28 dB, and a VSWR of 1.07, which closely corresponds with both simulated and theoretical results. Furthermore, the antenna demonstrates a wide operational bandwidth of 12 MHz while maintaining a compact structure suitable for vehicles (similar to 2.9 m). This combination of enhanced impedance matching, stable bandwidth, and field-ready fabrication distinguishes it from traditional folded dipole designs used in the VHF range. We have compared the S-11 plots of the simulated results and the fabricated results. The characteristics of a folded dipole antenna are comparable to those of a dipole Antenna, and HFSS software can be utilized to design and assess it. At the conclusion of the investigation, the simulated return loss result for the folded dipole antenna aligns well.
