卷 29, 编号 3 (2019)

Introduction. The classical topology optimization leads to structural type and general layout prediction and gives a rough description of the shape of both the external and internal structure boundaries. However, Reliability-Based Topology Optimization (RBTO) model produces multiple reliability-based topologies with high levels of performance. The aim of this work is to study the effect of reliability changes on the obtained topologies.
Materials and Methods. The developed Gradient-Based Method (GBM) has been used efficiently as a general method for several applications (statics and dynamics). When considering several reliability levels, several topologies can be obtained. In order to compare the resulting topologies, a shape optimization is considered as a detailed design aspect.
Results. Numerical applications are carried out on an MBB (Messerschmitt-Bölkow-Blohm) beam subjected to a distributed load. The DTO model is carried out without consideration of reliability concept. However, for the RBTO model, an interval of reliability is considered that produces several topologies. Here, the randomness is applied on geometry and material parameters. The application of the shape optimization algorithm leads to reduced structural volumes when increasing the reliability levels.
Discussion and Conclusion. In addition to its simplified implementation, the developed GBM strategy can be considered as a generative tool to provide the designer with several solutions. The shape optimization is considered as a numerical validation of the importance of the different resulting RBTO layouts.

Introduction. Recently the issue of decentralised (autonomous) power supply of certain rural consumers has been increasingly considered. Various small power generators using local and renewable energy sources can be applied for this purpose. So a consumer must choose the best-suited energy-generating source.
Materials and Methods. The findings of energy audits, which were conducted by the Institute from 2003 to the present day, were used to evaluate energy consumers and determine operation modes of equipment and load schedules. Complex index of the negative impact of heat and electricity generation on the environment was determined using the Spesivtsev ‒ Drozdov method of logical-linguistic modelling based on expert assessments.
Results. Energy sources can be divided into traditional (diesel generators and gas generator plants) or renewable ones (wind turbines, solar collectors, mini hydro systems). Energy source is chosen either with the help of the economic criterion, being the cost of one k·Wh of energy or the criterion of environmental compatibility, or total specific emission of pollutants from energy generation at local generating sources (g/k·Wh). Here, not only the quantity of emissions, but also the harmful effect on the environment is considered.
Discussion and Conclusion. For the choice of energy supply sources, the coefficient of energy-ecological compatibility is proposed, being the product of the cost of one k·Wh of energy generated and specific emission of pollutants. The optimal value of this factor is the smallest, which accounts for both economic and environmental feasibility of energy generating sources.

Introduction. The existing methods of assessing the technical condition of power hydraulic cylinders do not allow one to conclude about the need to restore worn surfaces of parts. The data on limit values of wear of parts (wear and tear value at which a decision is made to repair) in technical requirements to overhaul and other technical documentation of hydraulic cylinders are not currently available. The aim of the study is to determine limit values of wear of working surfaces of hydraulic cylinder parts of C series.
Materials and Methods. To assess the technical condition of hydraulic cylinders used, the authors developed a device on the basis of the stand KI-28097M-GOSNITI, equipped with an independent hydraulic station and load hydraulic cylinder, at which bench tests were carried out in the operation of С series hydraulic cylinders to determine overall efficiency values.
Results. Results of bench and micrometer tests of the former hydraulic cylinders of the C series (C75/30, C90/30, C100/40) are presented. The regression model of the relationship between total efficiency of C series hydraulic cylinders (C75/30, C90/30, C100/40) and wear of working surfaces of parts was obtained. According to this regression model obtained using the method of steep ascent, limit values of wear of the working surfaces of C series hydraulic cylinder parts (C75/30, C90/30, C100/40) were determined.
Discussion and Conclusion. 19,5 % of hydraulic cylinders of C series (C75/30, C90/30, C100/40) were operated in an out-of-limit condition. In case of technical service companies carrying out the input control of to-be-repaired hydraulic cylinders, limit values of wear for hydraulic cylinder surfaces, determined by the method of steep ascent, allow for making proper decisions on the need of their restoration.

Introduction. The article substantiates the need for high-temperature processing of feed ingredients. Principles of operation and design features of the applied methods and equipment for feed production are considered. Phase transitions, along with advantages and energy, technological, and technical drawbacks are highlighted. The aim of the study is to justify a possibility of creating high-efficiency production lines using heat treatment of feeds by application of heat valves ensuring continuous loading of raw materials into a reactor and discharge of the treated feed at high pressures and temperatures.
Materials and Methods. It is proposed to transfer the process of barothermal processing to a higher zone of the phase diagram of the system p,t (pressure and temperature). This is a section of the superheated steam zone with temperature 300–374 °C, pressure 12–21 MPa and treatment exposure 30–60 seconds, which replaces costly processes of normalizing, expansion, extrusion and granulation. The change in enthalpy in the pressure range 0–21 MPa and temperature range 0–600 °C is shown. Thermal modes are presented as formulas which is the basic condition for the use of digital technologies.
Results. The design of the reactor with a thermal gate for loading and unloading, being the main unit of the production line of the feed heat treatment, was proposed. The results of the study are fundamental for the development of the sample flow low-capacity line.
Discussion and Conclusion. The transfer of the process of barothermic processing of feed into the zone of superheated steam allows for the transfer of poorly digestible elements of grain and legumes in easily digestible, pathogen-free feed. Advantages of the reactor and line include the user-friendly design, energy saving and possibility of implementation of advanced digital technologies.

Introduction. The force required for stripping the ear is one of important parameters characterizing the process of stripping. The force varies within certain limits depending on the type of plant, grain moisture, and structural and morphological parameters of the ear. A series of experiments was carried out to determine forces of different types of wheat stripping.
Materials and Methods. Experimental studies were carried out in the Kaluga Oblast in the fields of Kaluga Research Institute of Agriculture. The study dealt with wheat varieties “Kasar”, “Moskovskaya 56”, and “Moskovskaya 40”. Ear parameters were estimated directly before testing as structural and morphological parameters of the ear can change significantly depending on growing conditions. It was suggested that such parameters as the width and thickness of the ear affect the process of the latter interaction with stripping fingers.
Results. Forces of stripping the said wheat varieties were obtained using stripping fingers with a gap of 5–7 mm. Stripping forces of the “Kasar” wheat varied from 17,4 to 24,2 N, under conditions of the gap of 6 mm, and from 13,4 to 16,8, with the gap of 7 mm.
Discussion and Conclusion. Dependence of the stripping force on the gap width of stripping fingers was confirmed by results of our experiments. Forces varied in the range of 16,5–20,6 N when stripping off “Moskovskaya 40” wheat in the case of the gap of 5 mm and 8,1–14 N in the case of the 7-mm gap. The effect of such ear parameters as the width, thickness and density was established.