The study of surface morphology of a silicon target after laser exposure, the formation and study of nanoparticles, obtained by laser ablation by ultrashort infrared pulses, were conducted. The material was processed using a yttrium aluminum garnet laser (LS-2134D) with a wavelength of 1064 nm, generating in a two-pulse mode (pulses are separated by a time interval of 3 μs, pulse duration is 10 ns, pulse repetition rate is 10 Hz, single pulse energy ~ 0.05 J). Alcohol solutions of silicon nanoparticles were obtained by laser ablation. It is shown that an ensemble of particles of different sizes (from 20 nm to 2.5 μm) is formed, which have no faceting. Using the method of scanning electron microscopy, the features of the morphology of the surface of the crater of polycrystalline silicon, which is in ethyl alcohol during pulsed laser processing in the double pulse mode, have been established. It is shown that the structure of the crater consists of silicon grains separated from each other by grooves; the material evaporates along the grain boundaries, and wide thermal etching grooves are formed. These results can be used to create solar cells.

The purpose of this work is to consider the problems of applying some standards containing reference scales of structures: 1763-68, 1778-70, 5640-68, 9391-80, 10 243-75, 13938.13-93, 22 838-77, 3443-87 (materials: oxygenated copper, pipe and structural steels, cast iron). It is shown that the normative base of standards for metallographic analysis is morally outdated. The main problem is the discrepancy between the increase in standards and real modern structures. Basically, microstructure standards use a magnification of 100 times, in particular, for the analysis of oxygenated copper, banding of the rolled metal structure, Widmanstätt structure, phosphide eutectic. The analysis of modern materials requires an increase of about 500...800 times. The magnification of 360…400 times, used in some scales, is also insufficient, in particular, for the analysis of structurally free cementite. Also, the quality of images of structures makes them difficult to use. A common disadvantage of the considered standard scales of structures is the absence of metrics in photographs, which does not correspond to the modern level of metallurgy and causes certain inconveniences when comparing structures. It is necessary to revise the standards governing the structure of metals and alloys. Research should be carried out to develop a new generation of standards based on the real structures of modern industrial alloys. It is also necessary to develop new methods of structure analysis. This applies primarily to analysis in image processing programs.

This article describes a device developed and manufactured on the basis of the Physical-Technical Institute of the National Academy of Sciences of Belarus, an induction hardening complex, and a range of parts suitable for processing. In addition, the article provides an example of the development of a technology for hardening parts from the moment a drawing of a part is obtained, indicating the required parameters of the hardened layer, until the determination of the technology of hardening, determining the type of inductor used and determining the necessary parameters of hardening, such as: size of the heating zone, size of the cooling zone, speed of mutual movement of the part and inductor, as well as the type and pressure of the quenching fluid. The article also presents examples of simulation results, various processes of heating and cooling parts using the UNIVERSAL 2D program, and offers an example of analysis of the data and possible ways to adjust the heating parameters in order to obtain the desired result, which allows to obtaining hardened layers of parts of the desired size and hardness. The importance of the stage of modeling of heating modes, especially in the case of large workpieces, is noted. Thus, the insufficient cooling rate of such parts can lead to warping, especially at a too high quenching temperature and heating depth. Self-tempering significantly affects the hardness values of the deep layers. Various combinations of heating modes for one type of parts are selected individually, according to the requirement of a customer and the type of generator used. The higher the depth of the heating zone, the higher the effect of self-tempering on the deeper layers is.

The phase transformations in alloyed iron-carbon alloys is largely related to diffusion of components, foremost to the carbon. For the analysis of diffusive processes in alloy steels, it is possible to use the mathematical methods of non-equilibrium thermodynamics. The equation for the diffusive fluxes of the system contains unknown in general case of coefficients activity of elements and vacancies, and their derivatives for to the concentrations, that extraordinarily makes it difficult being of values of cross coefficients. In the article a non-equilibrium thermodynamics methodology of calculation of diffusive fluxes at presence of two phases in alloy steels is described. It allows one to calculate both direct- and cross coefficients in the Onsager equations. Formulas for calculation of thermodynamics forces in the alloy steel – for iron, alloying element of substitution – chrome, of element of introduction – carbon and vacancies, are presented. Common expressions are suggested for calculation of cross-factors, motive forces and fluxes in the Onsager’s equations for a multicomponent thermodynamic system. The example of using the developed model to find changes in concentrations and diffusion fluxes over time is given. For the model system used, it was established that at the stage of predominant diffusion of carbon in the alloy steel, cementite inclusions with a size of about 18 nm are formed rather quickly (within ~ 200 s). The technique developed in the article allows one to perform diffusion kinetics calculations in multicomponent thermodynamic systems, which are also iron-carbon alloys and to control the size of the phases formed, for example, of carbide nanoparticles.

Two-step electrochemical anodization was used for obtaining matrices based on porous anodic alumina (MPAA). Three series of experimental samples were made: 1 – PAAM with thickness 1.3–2.5 μm and 70 nm diameter, 2 – 70.0 μm thickness and 50–75 nm diameter and 3 – 13.5–60.0 μm thickness and 100–200 nm diameter. The pore filling of MPAA was realized using electrochemical deposition. As a result Ni nanopillars, Ni and multilayered Cu/CoNi nanowires were formed. The scanning electron microscopy, vibrating magnetometry, voltammetry techniques and four-probe method were used for experimental samples investigations. The magnetic characteristics of Ni nanowires showed that nanowires in MPAA have ferromagnetic properties, since the coercitivity riches up to 750 kOe and squareness ratio up to 0.65. The study of the electrochemical behavior of the Ti/Al2O3/Ni nanocomposite material in the potential range from –450 to +450 mV in 0.9 % NaCl aqueous solution demonstrated its high corrosion resistance properties. The correlation of the GMR of multilayered Cu/CoNi nanowires to the topological parameters of MPAA, the number of layers, the MPAA and partial layers thickness, and chemical purity has been determined. Thus, it has been demonstrated the prospects of use of matrices based on porous anodic alumina as a base material for the template synthesis of functional ferromagnetic nanomaterials for various practical applications.

The article presents the results of a study of composite materials based on diamond-lonsdaleite abrasive (DLA) and various binders (Fe–Ti mechanocomposite, silicon carbide SiC). A metal-matrix composite material with a multimodal nano- and microlevel structure, characterized by increased adhesion of diamond grains to the binder, is obtained on the basis of impact diamonds and a Fe–Ti nano-mechanical composite. It is shown that the use of impact diamonds in comparison with synthetic diamonds makes it possible to reduce the pressure of thermobaric treatment by 30–50 % at the same sintering temperatures. The use of Fe–Ti–DLA composites in the process of magnetic-abrasive polishing (MAP) makes it possible to increase the removal rate of material based on silicon by 1.5–2 times and reduce the processing time by 30 % compared to ferroabrasive powder (FAP) based on synthetic diamonds. The effect of adding of silicon carbide on the process of obtaining a superhard composite material impact diamond – SiC is investigated. It is found that adding of SiC helps to reduce the defectiveness of the material and increase the homogeneity of its structure in comparison with the material without adding of a binder. In this case, an increase in the content of SiC and Si also leads to an inversion of the structure type of the superhard composite from polycrystalline to matrix. It is found that the additional use of amorphous soot and boron affects the refinement of the matrix structure of the composite material due to the formation of boron carbide and secondary finely dispersed silicon carbide.

The experience of using known and new steels to improve the manufacturability and strength of the main parts of machines, hardened by nitriding, is generalized. New approaches to manufacture of gear wheels hardened by nitriding, both when using aluminum-containing steels and a new material, steel 40ХМФА, are considered. To improve the efficiency and man ufacturability of parts production from aluminum-containing steel 38Х2МЮА, widely used in mechanical engineering, a fundamentally new technology of preliminary heat treatment of workpieces of parts – “incomplete hardening” has been developed, which provides both an increase in the machinability and accuracy of large-sized gear wheels, and an increase in strength due to the elimination of the brittleness of nitrided layer. The high hardness of the nitrided surface of the parts – up to 900 HV – also ensures high wear resistance of the parts. Gear wheels made of new aluminum-containing steel 20ХН4МФЮА solidified at the nitriding stage, have strength characteristics equal to cemented parts, which allows not only increasing the bearing capacity of a number of products, but significant simplification of the technology of manufacturing precise parts that are complex in shape, replacing carburizing with nitriding, thereby eliminating the necessary after-carburizing finishing operation – grinding. Steel 40ХМФА, which does not contain aluminum, has increased heat resistance, hardenability and machinability of parts, as well as the characteristics of their hardened layer. The nitrided layer of gears 0.5–0.7 mm thick does not contain brittle components, which, with a core hardness of 300–320 HB, excludes its “flaking” and subsequent destruction of parts. The use of 40ХМФА steel makes it possible to solve the problems of reliability and service life of large-sized nitrided gears, but it is also promising for the entire range of gears with internal gearing, as well as parts of movable spline gearings. These characteristics also in some cases allow replacing the carburizing of gears (modulus less than 4 mm) by nitriding when using 40ХМФА steel.

The results of modeling and experimental study of heat and mass transfer in a dense blown layer of plant materials under cyclic microwave exposure are presented. The two-dimensional mathematical model consists of the equations of conservation of the mass of the gas phase, filtration, heat and mass transfer in phases, which take into account the internal resistance to heat and moisture transfer in the particles when determining the heat and mass transfer coefficients. In this case, the dependences of the heat of the phase transition on the humidity of the particles, their shrinkage during dehydration, and the dependences of the effective coefficients of thermal conductivity of the gas and vapor diffusion on the filtration rate are taken into account. The simulation results of drying chopped potatoes in a dense layer with a cyclic microwave convective energy supply are presented. The possibility of intensifying the process of moisture dehydration and reducing its duration compared with the convective method is shown. Comparison of calculated data with experimental data confirms the adequacy of the model.

A method is presented for obtaining activated carbons (highly porous carbon materials) based on plant (wood) raw materials using a developed and manufactured experimental setup, consisting of a steam generator, a superheater, a pyrolysis and activation chamber and a cooler with a heat exchanger with forced convection. The analysis of the features of chemical and physical activation of charcoal, obtained by pyrolysis of wood raw materials, is carried out, and a conclusion is made about the advantage of physical activation, based on the use of water vapor as an activating agent. A description of the results of experimental studies carried out using the developed installation is given. These results confirm the conclusions of other studies that excessive pressure increases the mass yield of solid products formed during the thermochemical conversion of plant biomass. It was found that an increase in pressure, at which pyrolysis occurs, leads to an increase in the carbon content in charcoal. So, with an increase in pressure at which pyrolysis was carried out, from 1 to 8 atm, the carbon content in charcoal increased from 88.3 to 93.7 wt.%. Data on the efficiency of physical activation of solid products of pyrolysis of woody biomass using water vapor are presented and a conclusion is made that this direction is promising in the development of the foundations for the production of highly porous carbon materials.

In the work, the authors investigated the possibility of using the results of analytical solutions of the linear differential equations of unsteady heat conduction with constant heat transfer coefficients to calculate the temperature of the material during heat treatment of leathers. Heat treatment of natural leathers as heat-sensitive materials is carried out under mild temperature conditions and high air moisture contents, the temperature does not undergo significant changes, and the heat transfer coefficients change almost linearly. When using analytical solutions, the authors made the assumptions that for small temperature gradients over the cross section of a thin body, the thermal transfer of matter can be neglected and for values of the heat and mass transfer Biot criteria less than unity, the main factor, limiting heat and mass transfer, is the interaction of the evaporation surface of the body with the environment; so, in solving the differential heat equation we can restrict ourselves to one first member of an infinite series. In this case, a piecewise stepwise approximation of all thermophysical characteristics with constant values of these coefficients at the calculated time intervals was applied, which made it possible to take into account the change in the transfer coefficients throughout the entire heat treatment process. Processing of experimental data showed that in low-intensity processes with reliable values of the transfer coefficients, it is possible to use the results of solutions of differential equations of unsteady heat conduction in heat transfer calculations. The results of the study of heat transfer during drying of leather confirm the laws of temperature change established experimentally. Together with experimental studies of drying processes, analytical studies are of great practical importance in the development of new methods for calculating heat and mass transfer in wet bodies.

The regularities of the influence of the moisture content of expanded clay on the values of the reflection coefficient of electromagnetic radiation (EMR) of this material in the frequency range of 1–17 GHz have been established. The relationship between the size of fractions (pore size) of expanded clay and the operating frequency range of the EMR screen samples has been determined. It is shown that a twofold increase in the moisture content of expanded clay with fractions of 1…4 and 10…20 mm provides an extension of the operating frequency range of the EMR shield samples made on the basis of this material, with a decrease in the reflection coefficient of the test samples by 1.7 and 3 times, respectively. It was found that an increase in the moisture content of expanded clay from 19 to 40 % with a decrease in the size of its fractions from 10…20 to 1…4 mm and a pore size from 0.1…0.2 to 0.01…0.06 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 7.7–17.0 GHz, and an increase in the size of expanded clay fractions from 1…4 to 10…20 mm with an increase in the size of its pores from 0.01…0.06 to 0.1…0.2 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 1.0–7.7 GHz. It is shown that the practical use of these regularities makes it possible to form EMR screen samples with reflection coefficients from –2.8 to –22.0 dB in the frequency range 1–17 GHz, which makes it possible to recommend them for use when creating shielded rooms.

It is proved that the main prospects for improving the insulating means of respiratory protection are related to the chemical method of oxygen reservation. To increase the efficiency of its use, it is necessary to use the resource of the dead layer of the chemosorbent and prevent the sintering of the granules of the oxygen-containing product under the action of exothermic heat. This is achieved by faster pulsed passage of exhaled air through the frontal layers of the chemosorbent and its slow filtration through the rest of the regenerative cartridge. To evaluate the effectiveness of such a technical solution, a mathematical model of air regeneration in an insulating breathing apparatus with an uneven rate of exhalation filtration through a regenerative cartridge is constructed. The dependencies on the time and coordinate of the concentration of CO2 molecules in the air stream and the share of the use of the protective resource of the regenerative cartridge are obtained. Using numerical experiments, the optimal coordinate of the air flow filtration rate jump was determined to prevent sintering of the granules. Depending on the amount of pressure damping on exhalation and inspiration for the RHS respirator, an increase in the protective effect of the device was determined and a decrease in the power of exothermic heat sources in the frontal layers of the oxygen-containing product was calculated. The results obtained confirm the effectiveness of the considered improvements of the design, which make it possible to increase the reliability of insulating breathing apparatus on chemically bound oxygen and to increase the efficiency of using their protective resource.

The article explores the syndrome invariants of АГ-group of automorphisms of Reed–Solomon codes (RS-codes) that are a joint group of affine and cyclic permutations. The found real invariants are a set of norms of N Г-orbits that make up one or another АГ-orbit. The norms of Г-orbits are vectors with 2 1 Cδ− coordinates from the Galois field, that are determined by all kinds of pairs of components of the error syndromes. In this form, the invariants of the АГ-orbits were cumbersome and difficult to use. Therefore, their replacement by conditional partial invariants is proposed. These quasi-invariants are called norm-projections. Norm-projection uniquely identifies its АГ-orbit and therefore serves as an adequate way for formulating the error correction method by RS-codes based on АГ-orbits. The power of the АГ-orbits is estimated by the value of N2, equal to the square of the length of the RS-code. The search for error vectors in transmitted messages by a new method is reduced to parsing the АГ‑orbits, but actually their norm-projections, with the subsequent search for these errors within a particular АГ-orbit. Therefore, the proposed method works almost N2 times faster than traditional syndrome methods, operating on the basic of the “syndrome – error” principle, that boils down to parsing the entire set of error vectors until a specific vector is found.

Problems of architectural and functional construction and a heterogeneous network structure of intelligent control system of technological and industrious assignment have been considered. Complex research of the intelligent system is based on the modern paradigm of convergence of technical, algorithmic and software solutions. The concept of convergence of system solutions in the technology of construction of intelligent systems presupposes digitizing of physical values at sensor measurements, as well as uniform depiction and successive conversion of values of each controlled parameter with a certain set of scales. For solution of this task a functionally full set of scales; natural values of measured physical parameters; results of sensor conversions of physical values; results of parameters measurement in the format of integer valued binary codes; parameter values in the format of real scaled binary numbers were proposed. Unified algorithms of digitizing results of direct measurements of continuous parameters and their representation in the format of ρ-bit integer valued binary codes, as well as conversions of measured parameters in the format of real scaled binary numbers and their depiction in the scale of natural values of physical parameters were built with this set of scales. Operations with digitized physical parameters were specified in tracts of the intelligent system: calibration of results of indirect measurements; digitizing of discrete sensor signals; digital filtration of measurement results; adjustment of measuring tracts; intellect control of executive mechanisms. The consequence of application of convergence provisions is similarity of morphological construction, as well as schematic uniformity of implementation of information processes and cycles of control in the systems. The results of analysis of the functional construction of the intelligent system may be used, for example, for construction of hybrid systems of industrial automation.