№ 1 (2023)

Based on the results of experimental observations, mathematical models of the impact of the factors under study on repression-wave colmatation are obtained. The values of the factors are established at which mud solutions acquire a higher resistance to sedimentation of the solid phase due to its concurrent dispersion increasing the efficiency of colmatation of absorbing hole sections.

The dynamics of a rotor with a massive disk is considered for the case of interaction with oscillation limiters represented by viscoelastic supports discretely arranged in the disk rotation plane. Differential equations that describe the transverse radial and angular rotor oscillations in the course of rotation are obtained. The solution is presented in the form of a second-kind integral of the Fredholm equation. The supercritical rotor behavior after the Poincaré–Andronov–Hopf bifurcation caused by internal friction in the shaft material is studied. A generalized definition of the rotor precession index has been introduced, making it possible to calculate the frequency and direction of precession based on the information concerning transverse rotor oscillation.

There are two methods developed for determining residual stress in “hard” topocomposites coatings, characterized by the occurrence of an interfacial fracture at the coating–substrate interface during instrumental indenting. The novelty of the techniques lies in the analysis of the pyramidal indenter indentation diagram obtained as a result of a repeated indentation cycle. The results can be used in practice and in scientific research to quantify the type and value of uniaxial residual stresses in thin hard topocomposite coatings, the substrate material of which differs significantly in hardness from the coating material.

A comprehensive study of the EP648 Ni-based superalloy obtained by selective laser melting followed by high-temperature annealing has been carried out. The macro- and microhardness have been studied, and the microstructure has been analyzed, while tests for brittle fracture resistance were carried out. The quantitative and qualitative analyses indicate possible structural deviations affecting the properties of products.

For the first time, it has been shown that the enzymatic hydrolysis of corn and potato starch affected by β-amylase can be intensified using wave resonant effects. It has been established that the concentration of sugary substances formed resulting from the fermentation of corn starch, after two hours of resonant wave treatment is 3.5 times higher than it is in the case of the traditional stirring mode. In addition, the wave treatment technique provides an increase in the yield of sugars in the course of the enzymatic processing of potato starch. The obtained results represent a basis for the development of highly efficient resource-saving wave technologies for the production of sugary substances and porous starches by means of enzymatic hydrolysis.

In this study, practical recommendations for the production of aluminum coatings by the cold gas-dynamic spraying method (CGDS), as well as for the methods of aluminum coating strengthening by a ceramic component with the formation of a gradient structure, have been developed. The resulting ceramic-metal coatings have the following key optimization parameters: high adhesive strength (more than 70 MPa), high Vickers hardness (more than 480 MPa), and low porosity (less than 0.5%). These functionally graded coatings can be used to protect the elements and assemblies of machine-building equipment from wear.

It is proposed to introduce into the structure of FFS machines a drive for the displacement of batcher nozzles with a velocity amounting to the velocity of the belt with molded containers. It is shown that such a drive, owing to the combination of dosing and transport operations at a high level of doses should remove the dosing procedure from the list of limiting operations. This could make it possible to halve the number of necessary batcher channels in the case of batch automatic lines, where the doses are small, with simultaneously increasing the dosing intensity for each channel. A method is given for choosing a dosing pattern based on the elements of a Direct Filling system and on determining the optimal row order that, while maintaining the minimum machine cycle of the line, provides the maximum load of the dosing system.