The article considers one of the approaches to modeling the process of mixing of polydisperse powders, which includes three main fractions of different sizes, the shape of which is close to spherical. The work is aimed at reducing material costs at the stage of development of mixing processes by reducing the number of experiments. Aiming to obtain the most uniform mixing with the minimum time of the technological process, the model is based on the target function for a certain number of iterations of mixing of the composition to obtain the required (maximum possible) density of the package of mixed solid particles.

To develop a model of the mixing process, one of the heuristic algorithms – the “metal annealing method” – was used. As a representative element of the model, an elementary cell in the form of several hexagonal densely. Packed particles around one introduced into the composition of the composite material (in a small amount, from 5 to 15 %) as a modifier was adopted. The mo del is formalized with the condition of averaging the particle sizes within each fraction, as well as the morphology of their surface. The number of particle repackaging iterations is calculated by the probability of obtaining the minimum amount of voids in the representative element and the uniformity of distribution of the modifying element.

Comparison of the values obtained during the simulation with the measured values of the mixing results on a specific mixer will form a scale of compliance of the simulation results with the operating modes of the process equipment. This will make it possible to predict the appropriate mixing modes at the stage of development of the technological process with the possible system of fluctuations in the characteristics of the supplied raw materials and, thereby, to create a methodological basis for the formation of quality management of manufacturing heterogeneous composite material. The model can be adapted for polydisperse powders with the content of the main fractions of more than three.

The structure and microhardness of an aluminum alloy with additives of nanostructured cubic boron nitride (cBN) after treatment under high pressure and temperature are investigated. А nanostructured powder of cBN with primary particles within 50–200 nm is used as a filler. A preliminary chemical-thermal modifying of the nanostructured cBN, which consists in its high-temperature annealing in the temperature range of 750–950 °C in a medium of aluminum-contai ning compounds, is carried out to increase the chemical affinity of the nanostructured cBN to the aluminum matrix. It is shown that the modifying of nanostructured cBN with aluminum increases the strength of the additives retention in the aluminum matrix. At the same time the increase in the concentration of BN additives from 1.5 to 5 wt.% as well as the increase in the treatment temperature at a fixed pressure promotes the increase in the microhardness of the material by a factor of 1.5 to 2 as compared with the base aluminum alloy without the addition of a modifier. An increase in the cBN concentration to 5 % by weight results in an increase in the fraction of smaller particle conglomerates (1–5 μm) in the material and in a decrease in the size of large inclusions to 10–20 μm. In this case, the distribution of BN particles in the aluminum matrix is more uniform in comparison with a material with a cBN content of 1.5 wt.%. In the material with the growth of temperature up to 1000 °С, cBN in aggregates is recrystallized with the formation of single-crystal (polycrystalline) particles with the size of 1–10 μm  with faceting specific for cBN micron particles.

Using a hybrid method of cathodic arc (PVD) and chemical (CVD) deposition from the gas phase, a new type of coatings containing high amount of sp3 bonds of carbon, capable of absorbing effectively light has been developed.

This thin film material is a promised one for optical devices operating in open space environment as antireflective coating  for photoreceiver bodies. The hybrid method permits to obtain effective light absorbing coatings having excellent mechanical and tribological properties and is able to sustain temperature cycling in a range from plus 150 to minus 100 oC.  The optical characteristics of DLC coatings were studied depending on the content of sp2bound content. The combined physical and chemical deposition of DLC coatings allows to achieve a sufficiently high light absorption (a~10 5 cm–1) and low reflection with a relatively small coating thickness about 1 mm. It has been established that the antireflective properties of such coatings depend on the conditions for their preparation, first of all on hydrocarbon gas pressure

The results of studying of the structure and properties of the In – 42 at.% Sn alloy in the form of foil obtained by the method of rapid solidification with a cooling rate of the melt of at least 10⁵ K/s are presented. X-ray diffraction analysis showed that the phase composition of the alloy corresponds to the equilibrium state diagram. Foils consist of an InSn₄ compound (γ-phase) and an In₃Sn compound (β-phase). The grain structure of foil was studied by electron backscatter diffraction technique. It is established that the foil have a microcrystalline structure. The parameters of the microstructure are determined by the method of random linear secants: the volume fraction of the phases, average chord length of the random linear secant on the inclusions of each phase, the specific surface of the interface. Microstructure and distribution of components was also studied for both foil surfaces. The texture of both phases of the polycrystalline foils was studied by the method of inverse pole figures. It is established that the initial foils of the investigated alloy are in an unstable state. It is shown that an increase in the microhardness of the alloy during aging and annealing caused by change in the parameters of the grain structure.

The use of variable profiles in engineering is the most effective way to reduce metal consumption and improve performance, increase the lifetime, reliability of machines and mechanisms, and reduce costs for their production, repair and operation. The purpose of the present work is to systematize the blanks of machine-building industries obtained by methods of plastic deformation and to develop general principes of the con cept of creating single-stage rolling mills on the basis of analysis of their design and operation. Three main classes of profiles are distinguished, differing in the type of the initial workpiece: strip, shaped and tube periodic billets. All these types of blanks can be used as semi-finished products for the production of the main parts of suspension and chassis of cars. Strip billets are widely used for the manufacturing of elastic suspension elements, tubular – for manufacturing of hollow body parts with increased requirements for strength and rigidity, in particular, driving axle housing, semi-axles of cars and trailers, jet engine casings. Shaped periodic profiles of various shapes are used as blanks for hot volumetric stamping. Mills and automatic lines for the rolling of blanks of low-spring springs, under-springs, guide bearings of air suspension, rolling of the bars of the front axle beam, manufacturing of protective elements and semi-axes of agricultural machinery developed under the guidance or with the direct participation of the author are presented. General requirements for the deformation equipment of machine-building industries are formulated. Recommendations to use induction heating and high-temperature thermomechanical treatment are justified. It is not recommended to change the direction of movement of the workpiece in the process chain. As a power drive equipment it is better to take electromechani cal, rather than hydraulic systems. It is also advisable to choose separate drives for each working element of the equipment.

Experimental investigation of the radial distributions of tangential and longitudinal velocities, total and static pressures in the vortex zone of a cyclone-bed chamber of diameter 0.21 m has been carried out. The experiments were carried out at various regime parameters (fraction of bottom blast, total air volume flow) and geometric parameters (diameter and shape of the outlet) of the chamber, and also in the presence of a fixed or fluidized bed of granular material. The influence of nonisotherm of bottom and tangential blast on the distribution pattern of velocity and pressure in the vortex zone of the cyclone-bed chamber is investigated. There was determined the influence of bottom blast temperature on the longitudinal velocity of air in the central part of the vortex zone chamber.  It is shown that the diameter of the outlet has a significant effect on the pressure in the chamber. The longitudinal velocity in the central part of the chamber is practically independent of the shape of the outlet. The presence of the fluidized bed has an effect on the hydrodynamics of the cyclone-bed chamber vortex zone. In the presence of the fluidized bed there has been a violation of the self-similarity of hydrodynamic dimensionless parameters distribution in the vortex zone. The obtained experimental data were summarized within the framework of the similarity theory with the use of a dimensionless quantity characterizing the hydrodynamics of an inhomogeneous fluidized bed – the Froude number (Fr). The use of the Froude number makes it possible to take into account the effect of the fluidized bed hydrodynamics on the features of air velocity and pressure distributions in the vortex zone, and also takes into account the influence of such an important factor as the fraction of bottom blast.

An algorithm of finding polynomial solutions of boundary-value problems on nonstationary heat conduction with a time-dependent boundary condition of the secondary kind for bodies having a plane geometry, a cylindrical symmetry, or a spherical symmetry is presented. Thе algorithm is based on the introduction into consideration of the boundary characteristics in the form of a definite set of k-fold derivatives and n-fold integrals with respect to the time function of the heat flow on the surface of a body representing a boundary condition. Two stages of the heat-conduction process were considered separately: 1) the temperature front does not reach the center of a body and 2) the temperature front reaches the center of the body, and it is heated throughout its thickness. By the example of symmetric heating of a lengthy plate with a constant and variable heat flows, a very high accuracy of the proposed approach based on the integral method of boundary characteristics (BChIM) was demonstrated. As compared to the method of additional boundary characteristics, the BChIM makes it possible to de crease the relative approximation error (at one and the same polynomial degrees N) by  three to five orders of magnitude and by larger values and brings it to a negligibly low level (0.00028 %  at N = 11 and 0.000025 % at N = 14). It was established that, with each next approximation (with addition of three degrees into the polynomial), the approximation error decreases by an order of magnitude for the first stage of the process. An efficient algorithm of finding the eigenvalues of a boundary-value problem on heat conduction, based on the introduction into consideration of an additional function corresponding to the largest, in sequence order, boundary integral characteristic, is prtsented for the second stage of the process. Thе algorithm makes it possible to transform the integro-differential equation obtained on the basis of the BChIM into the ordinary differential equation with zero initial conditions. The calculations of the temperature at the center of the plate have shown that the approximation accuracy of the approach proposed is very high.

In the paper, the authors analyzed the solution of the differential equation of non-stationary heat conduction for an unbounded plate during the heat exchange of plate surfaces with the surrounding medium according to Newton’s law at a constant temperature of the medium. To use the results of solving the equations in the drying of thin flat materials, the dependence of the heat transfer coefficients on temperature and moisture content was studied. As a result of studying and analyzing a number of literature sources, the regularities of the change in the heat transfer coefficients during drying are established with high reliability. Studies of drying of thin wet plates of white and red clays with known heat transfer coefficients have shown that for small values of the heat transfer criterion of the Bio and small temperature gradients over the section of a thin material, application of the results of solutions of the heat transfer equations gives completely satisfactory agreement between the calculated and experimental values of the temperatures and the duration of drying. It is established that for small Bio numbers, the main factor is the external heat and mass transfer of the surface of the material with the surrounding medium and the rate of drying depends little on internal mass transfer. It is shown that the use of numerical methods for solving differential equations is possible with varying degrees of approximation only for accurate and reliable dependences of heat and mass transfer coefficients on moisture content and temperature. For a number of materials with known heat transfer coefficients, the use of analytical methods in calculations is of considerable interest and brings the theory closer to the practice of drying.

The work provides the analysis of power characteristics of the industrial equipment – ionic nitriding applications – with different types of vacuum chambers – with hot and cold walls. The calculations results and experimental researches of thermal balance of the system “melt-wall chamber” at the process of plasma nitration for industrial applications are given. The work examines the influence of heat-shielding screens quantity in the applications with cold walls on the internal screen temperature and power of thermal losses at warming up parts melt and at its isothermal endurance. It has been displayed the significant influence of the discharge chamber geometry on the discharge power value which is necessary for the melt warming up and its exposition at the certain temperature – the less are geometrical sizes of the chamber (diameter and height), the smaller is the power of the smoldering discharge which is required for ensuring necessary melt temperature. It is shown that at sufficient melt parts distance from the chamber walls, the voltage drop on the skeleton of the smoldering discharge can be tens volts that causes the decrease of cathodic falling potential and, respectively, the increase of the electric power which is required to maintain necessary melt temperature in comparison to melt which is as close as possible to chamber walls. It leads to the fact that at more dense loading, smaller specific consumption of the electric power to ensure the necessary depth of the nitrated layer is required; at the same time the specific energy consumptions by the melt temperature of 525–530 °C are 0.6–1.6 kW∙h/kg, depending on the loading extent of the chamber. It has been displayed that at ionic nitration, the value of working gas pressure must provide the deviance of the smoldering discharge i. e. the whole area the cathode –melt must be captured by the discharge luminescence.

At present, the technology of diamond blade whetting with nano-sized roughness is widely used at the manufaсturing of metal-optical products, first of all, mirror-reflectors for “transportation” of powerful laser energy flows. Optimum material for mirror-reflectors is an aluminum alloy AMg2, which surface purity, is affected by the quality of preliminary mechanical heat treatment during superfinishing treatment by diamond whetting.

Preliminary machining of the surface with a carbide cutter and finishing with a diamond cutter (with a radius of curvature of the blade less than 0.05 μm) were performed on a precision lathe of the MK 6501 model with a vertical spindle position on an air bearing. Thermal treatment was carried out in the laboratory electric furnace SNOL 58/350. Various modes of preliminary heat treatment, machining with a carbide cutter and finishing with a diamond cutter of substrates (20×20×7 mm³) were tested. The surface state analysis was carried out using the PMT-3 microhardness tester, the SolverPro P47 atomic-force microscope (AFM), and the experimental probe-electrometry device. The control of the electrophysical parameters of the surface was carried out by recording the distribution of the electron work function (RWF) by the contact potential difference with the processing by the microprocessor measuring transducer of electrostatic potentials. The recorded changes in the RWF characterize the physic-chemical and mechanical parameters of the surface of mirrors and indicate the presence of a different type and nature of defects.

Modified preliminary mechanical-thermal treatment allowed to improve the cleanliness of surface treatment of substrates. Finishing nanoscale diamond blade processing, including the complete removal of the surface layer that was disturbed by previous operations, bring to the greatest possible improvement in the quality of the surface in terms of the uniformity of the distribution of its electrophysical properties. As a result, according to the values and changes of the RWF, achievement of the specified performance characteristics of the product surface was monitored in order to optimize the technological processing modes in accordance with the functional designations of the devices.

The methods for increasing the efficiency of nanoscale diamond blade processing and performing researches of the electrophysical properties of the surface to control defects in the manufacture of metal reflector mirrors with high reflectivity and radiation strength for operation under extreme conditions.

The results of calculations of a nonlinear model of a tunable frequency gyrotron on a cone-shaped waveguide and the main wave TE01 are presented. It is shown that the adjustment range can reach 2.8 %. To extend this band, it is necessary to lengthen the cone-shaped part of the waveguide without changing the angle of increase in the radius of the waveguide.

The wave efficiency of a waveguide expanding along the axis is 21 % at a working frequency of 10 GHz. To achieve these parameters, it is necessary to divide the gyrotron electromagnet into two parts – the main electromagnet and auxiliary one, which has a limited length and can move along the waveguide. The second magnet can be made in the form of a set of individual electromagnets of limited length the set of electromagnets must fill the entire length of the cone-shaped waveguide. The fulfillment of this condition will allow to move the resonant magnetostatic field along the waveguide by switching the current in the coils of this set of electromagnets, which will exclude the mechanical movement of the auxiliary electromagnet. At a frequency of 200 GHz, the wave efficiency is reduced to 15 %, while the ohmic losses in the walls of the waveguide are 3 % of the power of the electron beam.

The dependence of the gyrotron efficiency on the initial angular spread of electron velocities was investigated. It was concluded that the initial angular spread of the electron velocities has very little effect on the efficiency of the tunable gyrotron.

The wave efficiency of a waveguide narrowing in length can reach 29 % at a frequency of 200 GHz, ohmic losses in the walls of a copper waveguide amount to 4 % of the power of the electron beam. Calculations have shown that a lamp backward wave gyrotron with a waveguide narrowing along the axis is more efficient than the version of the gyrotron traveling wave tube. However, in both cases, the synchronous value of the magnetostatic field must be displaced along the axis, depending on the required operating frequency, otherwise there occurs either a rearrangement of the electron beam or a return of the energy to the high-frequency field by the electron beam.

The article describes an approach to ensuring stability and controllability of unmanned aerial vehicle (UAV) with unknown aerodynamic characteristics by computer simulation of the airplane flight along a given route in the meteorological standard atmosphere. This computer model takes into account the programmed flight of an unmanned aerial vehicle in the meteorological atmosphere along a given route with waypoints. For this purpose the model incorporates 5 feedback systems (FS) with autopilot (AP) that ensure the stability and controllability of an airplane. Besides the autopilot and the airplane glider the control system encompasses the Kalman filter and a strapdown inertial navigation system. The appropriate structure and parameters of the control system of the model were chosen on the basis of practical technical solutions of the de veloped UAVs. The closed control systems of the model are developed according to the equations considering generation of aerodynamic forces and moments, a model of the standard atmosphere, the routing scheme and the feedback system with autopilot. The stability and controllability of  the model were analyzed according to  the theory of feedback systems with the graphic plotting of Bode magnitude plot and Bode phase plot. With a view to the assessment of dynamic and fluctuation errors of the control systems the model is represented by stochastic differential control system with the Kalman filter and the strapdown inertial navigation system in quaternions. The results of the computer simulation showed that the Kalman filter estimates the measured parameters with the noise reduction under 10 dB. The strapdown inertial navigation system influences the general dynamics of the control system during the assessment of its stability and controllability. Changing the band of the control system at the expense of external perturbations affecting the plane can lead to instability, and in order to avoid it the robust autopilot is recommended.