Issue № 3(19) Vestnik of Tver State Technical University. Series «Technical Science»

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• STRUCTURAL FEATURES AND APPLICATIONS OF MATERIALS FORMED IN ELECTROLYTE PLASMA
  Authors: V.V. NOVIKOV, Cand. Sc., O.O. NOVIKOVA, Cand. Sc., A.N. BOLOTOV, Dr Sc.
  Abstract: The factors influencing the structure and tribological properties of materials and coatings formed in an electrolyte plasma are determined. The main directions of microplasma modification of the friction surface of parts are considered: increasing its hardness and wear resistance, obtaining corrosion-resistant and decorative coatings, reducing the material consumption of the friction unit as a whole and replacing expensive materials. A multiple increase in the service life of hardened tribo-couplings is shown. Examples are given of obtaining ceramic materials with a solid lubricating filler that successfully operate under conditions of dry friction or limited lubricant supply. The basics of the original technology for obtaining a mineral-ceramic material, which is a matrix of aluminum oxide and dispersed diamond inclusions, are outlined and its properties are shown. Examples of the implementation of ceramic composite materials formed by microplasma oxidation in real tribodevices and the results of experimental studies of their tribotechnical characteristics are given.
  Keywords: microplasma electrolytic oxidation, microarc oxidation, coating, friction, wear.

• STUDYING THE CONTACT OF CONSTRUCTIONAL METALS UNDER THE CONDITIONS OF SEIZURE AT ELEVATED TEMPERATURES
  Authors: V.V. IZMAILOV, Dr. Sc., A.F. GUSEV, Cand. Sc., A.A. MITYUREV, Cand. Sc.
  Abstract: The conditions for the occurrence of seizure of metal surfaces under static contact and shear are studied. The effect of mechanical load and elevated temperatures on the process of formation of an adhesive joint in a contact has been studied. The description of experimental device and experimental technique is given. Quantitative values of the strength of adhesive joints are obtained and a theoretical analysis of the obtained dependences is carried out. It is shown that the shear of the contacting surfaces affects both the “seizure threshold” and the value of the adhesion coefficient at a given temperature and load. At that the values of temperatures and loads of seizure begining decrease, and the adhesion coefficients increase.
  Keywords: metal contact, adhesion, seizure, temperature, contact area, contact electrical resistance.

• SEALING WITH MAGNETIC FLUIDS
  Authors: A.N. BOLOTOV, Dr. Sc., G.B. BURDO, Dr. Sc.
  Abstract: Magnetofluidic seals for sealing gas media have found wide application in various industries due to their undeniable advantages. Nevertheless, such seals are not yet able to reliably seal liquid media with different polarities. The paper analyzes the physico-chemical processes that lead to the destruction of the magnetic fluid in the seal under the influence of the liquid medium in contact with it. The results of experimental studies of the sealing process based on the use of magnetic liquids based on siloxanes and triethanolamine, as well as non-magnetic liquids with different polarities are presented. It is concluded that for sealing polar liquid media, it seems promising to use oleophobic magnetic liquids containing a large amount of filler in the form of strong magnetic particles with a dispersion of 0.1...1 microns. It is shown that the magnetic fluid must have the smallest possible contact area with the sealed liquid and maintain the laminar flow regime.
  Keywords: magnetic fluid, seal, liquid medium.

• ON THE METHODOLOGY OF A FRICTION CONNECTION RESOURCE EVALUATION FOR COATED PARTS BY LIMITING WEAR CRITERION
  Authors: V.V. IZMAILOV, Dr. Sc., L.E. AFANASIEVA, Cand. Sc., M.V. NOVOSELOVA, Cand. Sc.
  Abstract: Analytical dependencies are proposed to predict the wear of coated parts, the hardness of which differs from the hardness of the base material. To describe the dependence of the material hardness on the distance to the friction surface, a formula was used that was obtained using the energy method for estimating the force of indenter penetration into a plastic material. The calculation of the resource of the friction unit according to the wear criterion is based on the J. Archard equation known in tribology, generalized to the case of a nonlinear (power-law) dependence of the wear rate on the hardness of the wear material and the applied normal load. It is shown that in this case, ignoring the hardness gradient when estimating the resource of a friction unit leads to an even more significant error than in the case of a linear dependence of the wear rate on hardness. Depending on the ratio of the hardness of the coating and the substrate, the resource of the friction unit is either overestimated or underestimated, which negatively affects the reliability and efficiency of the equipment. In the first case, the probability of a failure increases, in the second, part of the resource remains unused.
  Keywords: friction, wear, coating, hardness, resource, prediction.

• CONTROL OF THE MAGNETIZATION OF INDUSTRIAL PERMANENT MAGNETS FOR MAGNETIC-POWER MECHANICAL SYSTEMS
  Authors: A.N. BOLOTOV, Dr. Sc., O.O. NOVIKOVA, Cand. Sc.
  Abstract: A method for controlling the homogeneity of magnetization of magnets is proposed, based on the experimental determination of the magnetic field strength on the polar surface of a magnet of various shapes. If the experimental value of the magnetic field deviates from the calculated value determined by the characteristics specified in the corresponding GOST, the magnets are rejected by more than 10 %. To perform calculations of the magnetosilic properties of mechanisms, it is proposed to use an experimentally determined average value of magnetization. Theoretical formulas for determining the magnetic field of prismatic, cylindrical and annular magnets are obtained using the equivalent solenoid method.
  Keywords: permanent magnets, high-coercivity magnetic, magnetization, magnetic force, magnetic mechanisms.

• INCREASING THE CRACK RESISTANCE OF CARBONATE CONCRETE
  Authors: V.V. BELOV, Dr. Sc., T.R. BARKAYA, Cand. Sc., P.V. KULYAEV, Cand. Sc.
  Abstract: The dependence of mechanical behavior of carbonate concrete on strain rate is considered in the article. It has been established that this dependence is based on two different physical mechanisms: the fracture process, which affects the rate of crack formation, and the viscoelastic deformation of the undamaged (undamaged) cement paste. It is shown that cracking for plain and carbonate concretes should be taken into account when analyzing different aspects of the fracture mechanism and the influence of the deformation rate should be taken into account. It has been revealed that in order to form a complete picture of fracture of these concretes the mechanism of crack formation should be included in the analysis of various aspects of morphology of sample cross-sections and manifestation of crack growth signs.
  Keywords: fine-grained carbonate concretes, deformative properties, crack resistance, influence of limestone microfillers, chemical additives.

• ASSESSMENT IMPACT OF TECHNOLOGICAL PARAMETERS FOR FIELD DRYING OF THE PEAT LAYER DURING ITS EXTRACTION
  Authors: O.V. PUKHOVA, Cand. Sc.
  Abstract: The questions of the influence of technological parameters (water level, weather), which depend on the rate of drying of products, in the development of the peat field “Svyatinskoye”, and, more precisely, in the field drying of peat crumb obtained by milling the deposit, are considered. For the experimental maps of the production site the indicators of seasonal studies are given. For this purpose, the moisture content of the dried layer, indicators of groundwater level fluctuations and the volume of moisture, which was absorbed from the underlying deposit and rainfall, moistening the dried peat layer, were determined. On four maps with an open drainage network, weather conditions as well as groundwater level fluctuations in the map channels were monitored during the season. The complexity of laying of slot drainage and its influence on the water-air regime of the uppermost deposit during the ground water level variation during the season were analyzed. It is shown that slot drainage together with open channels has favorable effect on production site drainage. It has been established that ground waters under the action of gravitational forces, i.e. at the difference of pressures in the peat deposit and drains, seep into the cavity and then under the slope are discharged into the collecting network of open channels and are removed outside the drained production site. It is recommended to use the results of seasonal studies and analysis of moisture movement processes to develop and substantiate measures for improving the water-air regime of the peat deposit with the development of an intensive method of drainage as well as for maintaining the necessary conditions.
  Keywords: peat, peat deposit, peat layer, open drainage network, drainage, meteorological indicators, hydrological regime, groundwater level, drying processes.

• FIELD AMMONISATION OF PEAT
  Authors: E.Yu. CHERTKOVA, Cand. Sc.
  Abstract: The results of research related to the application of ammonia to peat to produce a peat-ammonia fertilizer are presented. The method of introducing ammonia water solution in the field before the swathing operation is proposed. For this purpose, constructive changes are made to the rake, which is used at the peat field in the technology of milled peat extraction.
  Keywords: peat, aqueous ammonia, nitrogen, absorption capacity acidity, fertilizer, modernization, application method.

• MODELING OF GREEN TEA DRYING PROCESS
  Authors: K.B. FAM, Postgraduate, P.M. MURASHEV, Postgraduate, V.N. BOGATIKOV, Dr. Sc.
  Abstract: The paper describes the design and simulation using MatLab and Simulink process of drying green tea in a conveyor belt dryer with fuzzy approximation of the dependence of the equilibrium moisture content of tea on its relative humidity and temperature. On the basis of comparison of calculated curves for the developed model, as well as on the basis of available experimental data on drying of green tea in a conveyor dryer the conclusion about their satisfactory convergence was made. The obtained models are recommended for practical application.
  Keywords: green tea drying, fuzzy set theory, drying mathematical model, equilibrium moisture, green tea moisture.

• INFRARED SEMICONDUCTOR GAS DETECTOR RESEARCH
  Authors: L.V. ILYASOV, Dr. Sc.
  Abstract: The results of experimental studies of an infrared semiconductor gas detector, created on the basis of a commercially available semiconductor converter of the PP-1 type, whose principle of operation is based on measuring the electrical conductivity of a semiconductor sensing element heated to a temperature of 400…450 °C when it comes into contact with flammable gases, are presented. It has been established that the change in the electrical conductivity of this element is accompanied by infrared radiation, which makes it possible to use the measurement of the intensity of this radiation by an infrared photodiode to obtain measuring information about the concentration of the analyzed gas. The designs of the detector and the laboratory installation for its research are described. The dependences of the detector signal on its main operating parameters are given, namely: on the concentration of the analyzed gases (hydrogen, propane) in the carrier gas (air) flow, on the supply voltage of the semiconductor sensing element, on the distance between the sensitive.
  Keywords: : infrared, semiconductor, detector, gas, experiment, concentration, radiation, metrology.

• ABSTRACT MODEL OF THE RELATIONSHIP BETWEEN EXISTING INFORMATION SYSTEM MODELING METHODS AND A SET OF IDEAS
  Authors: D.I. PRIKHODKO, Master, A.V. MOKRYAKOV, Cand. Sc., V.V. GORSHKOV, Dr. Sc.
  Abstract: The question of the interconnection of existing methods of modeling information systems is considered. Advantages of conceptual, mathematical, natural modeling are considered and described. It was shown that the original version of everything is ideological modeling, by which the authors mean an abstract semantic assumption. The difference between the idea and the concept was demonstrated. Several interaction options were built: linear, linear-variable, block diagram of a detailed option. At the same time, it was indicated for the latter that the transition function can be implemented on the basis of the necessary mathematical or logical apparatus. It has been shown that the simplest version of the model is the intersection between sets of each type of modeling.
  Keywords: mathematical modeling, conceptual modeling, natural modeling, ideological modeling, the relationship of modeling methods.

• EXPANDED INTERNAL STRUCTURE OF COMPUTER SYSTEM INTENDED FOR OPERATION IN EXTREME ENVIRONMENTAL CONDITIONS
  Authors: D.I. PRIKHODKO, Master, A.V. MOKRYAKOV, Cand. Sc., V.V. GORSHKOV, Dr. Sc.
  Abstract: The article discusses the issue of a detailed representation of the mechanisms of a computer system from the point of view of a system approach, which as a result allows you to determine the necessary criteria and a set of regulations for the development and operation of computer systems. Maintenance structure is considered for proposed structure of computer system.
  Keywords: structure of the computer system, extreme environmental conditions.