One of the ways to reduce the cost of heating production facilities in animal husbandry is the use of regenerative heat recovery plants. However, the existing designs of heat exchangers have a number of design flaws affecting their functionality, in particular, the uneven distribution of the air flow over the surface of a heat exchanger. This, in turn, does not provide for a more complete utilization of exhaust air heat. Using the example of a recuperative heat recovery unit UT‑3000, the authors consider the possibility of retrofitting it with an aerodynamic grid to evenly distribute the exhaust air flow over the heat exchanger surface and reduce energy costs for its operation. To do this, they analyzed the applicability of the aerodynamic grid. The size of a blade chord was taken into account as an optimisation parameter. The pressure losses calculated on the “fan – pallet – heat exchanger” section showed that the use of an aerodynamic grid with a “normal” number of blades would create a minimum airflow pressure loss of 0.73 Pa minimum airflow pressure loss of 0.73 Pa, which is 58% less than in the version without an aerodynamic grid. Further experimental study of the uniform airflow distribution over the heat exchanger surface aimed at improving the energy efficiency of the heat recovery unit requires a new design of a heat exchanger with an aerodynamic grid, taking into account the recommended range of “normal” number of blades from 16 to 21, the blade circumference arc of 95° and the blade pitch angle ranging between 68 and 82°.

To predict the thermal characteristics of an air solar collector mounted on the outer walls of the cowshed, the authors proposed a mathematical model based on the linear dependence of the change in the temperature of the heat-receiving surface during the day, taking into account variable environmental factors. The present study proposes to apply a quadratic dependence of the ambient temperature on the time of day. The ambient temperature and the flux density of solar energy reaching the vertical surface, depending on the time of day, differs for different regions of the country, seasons, as well as within the same season. The study aims to establish these dependences for the conditions of the Bryansk region based on the materials of actinometric observations of meteorological stations with a period of at least 5 years. The study measured direct solar radiation reaching the cowshed surface perpendicular to the sunlight. Equations were obtained for both clear sky and medium cloudiness conditions for the middle day of each month of the year assuming that the dependences would be characteristic of all days of a given month. As a result of the research, regression dependences describing the diurnal course of air temperature and solar radiation intensity for the median months of the seasons (January, April, July, and October) were obtained. The obtained results may help increase the accuracy of calculations of the temperature of the heat-receiving surface of ventilation and heating panels taking into account environmental factors and to provide forecasting of the thermal characteristics of the natural ventilation system of the cowshed.

Automatic brushing devices that improve the sanitary-hygienic condition of animal skin and create comfortable conditions are becoming widespread in modern dairy farms. To verify the developed mathematical model of cow skin cleaning, the authors carried out experimental studies on ten animals on a dairy farm. On the lateral surface of each animal three zones with the area of 10×10 cm2 were selected: the first area was not cleaned; the second area was cleaned “dry” with a brush; the third area was subjected to “wet” cleaning with a brush and detergent (soap solution). The temperature of the skin areas was determined for 15 minutes by the non-contact method using a pyrometer. The study results confirmed the effect of skin cleaning on the intensity of animal heat exchange due to increased convection and evaporation under heat stress. It was found that wet cleaning is the most effective method, when the skin temperature decreases by 4.1°C due to the increase in heat transfer by evaporation, while after dry cleaning it is 0.7°C. The developed mathematical model of cow skin cleaning establishes the relationship between the parameters of the brush bristle impact on the contaminated skin surface, the brush device and cleaning modes. The received dependences determine technical requirements and rational design and mode parameters of the brushing device to develop an automatic station of cow skin cleaning on farms.

Solid seeding should ensure uniform distribution of seeds over the cultivated area. The experimental seeder SV‑0.9, developed and improved by the authors, is equipped with a coil type seed-feeding device. It provides variable seed supply from each pair of coils of the seed-feeding device and ensures uniform seeding when following a straight path and a curved path. For solid sowing, it is necessary to provide uniform seed distribution over the cultivated area. For this purpose, two indicators can be used: the seeding uniformity factor and the average feeding area of a plant. The Gazon Bystriy lawn grass mixture was used to test the experimental seeder for determining the indicators of seed distribution uniformity. The tests were carried out under laboratory conditions. During the experiment, seeds were fed into the seed box and the seeding rate was set at 3.5 kg/100 m². Paper tape was marked into 10x10 cm squares and further divided into centimetre cells. The prepared tape was covered with glue. The seeds were sown on the sticky tape while the seeder was moving. The uniformity of seed distribution over the area was evaluated by counting the seeds in the square cells. According to the experiment results, it was found that the seeding uniformity factor ranged between 0.92 and 0.96, which corresponds to the indicators of GOST 31345‑2017, and the average feeding area per plant was 0.48 to 0.56 cm². The laboratory results prove the possibility of solid sowing by the SV‑0.9 seeder at a seeding rate of 3.5 kg/100 m².

The production of bionutrients in the conditions of industrial production and agricultural enterprises requires the development of technology and a production line for the production of bionutrients of stable quality without the use of chemical reagents. To this end, the authors have developed a technology and a technological line for the production of bionutrients based on the processing of animal waste into coprolites and the use of cavitation to increase their biological efficiency. The article presents the methodology and technological scheme of the production of bionutrients. The technology and the obtained bionutrient ABT-Plant were tested in the Belgorod region on sugar beet LMS-94. In the control sample, the seeds were moistened with water. In four variants, ABT-Plant bionutrient was treated: in the fi rst – seeds; in the second – spraying of vegetative sugar beet plants in the phase of 6-8 real leaves (20 g·t^-1); in the third – spraying of vegetative plants (15 g·ha^-1) before closing the leaves in the row spacing of sugar beet; in the fourth – seed treatment (20 g·t^-1) and spraying of vegetative plants (15 g·ha^-1) before closing the leaves in the row spacing of sugar beet. The positive effect of the bionutrient ABT-Plant on the productivity of sugar beet has been established. The best results were achieved when the ABT-Plant preparation was used twice during seed treatment (20 g·t^-1) and the vegetation period of plants in the phase of closing beet leaves in row spacing (15 g·ha^-1) provided an increase in the yield of sugar beet of 3.5 t·ha^-1. The sugar content of sugar beet increased by 5.5-6% compared to the control, the sugar harvest by 0.85 t/ha or by 11.2%.

Both the actual size of the part and measurement errors influence the results of tolerance control in repair production. For this purpose, the authors developed the mathematical model of reject estimation by probabilistic characteristics of parts sorting, taking into account the specifics of repair production and the shift of the distribution center relative to the tolerance field. They tested and evaluated the mathematical model of rejects estimation at machining for repair size of crankshaft main journals of the YaMZ‑238 engines. In case of incorrect rejection and incorrect acceptance of main bearing journals, the character of reject losses will be different. Incorrectly rejected crankshafts with journals having irreparable rejects will be sent for recycling. New crankshafts will be purchased to replace them, and there will be reject losses to the left of the scatter zone. Incorrectly rejected crankshafts with journals that have reparable rejects will be sent for remanufacturing. In this case, the loss per crankshaft is determined by the cost of rework, which is the loss to the right of the scatter zone. Incorrect crankshafts with journals having defects to the left and right of the scatter zone will be sent for reassembly. If the largest size limit is exceeded, the liners may rotate and the engine must be rebuilt, which increases losses significantly. In case of violation of the lower size limit, the shaft life will be reduced and losses will occur only for the consumer. In contrast to the existing methodology for calculating the sorting parameters, where the scatter zone coincides with the middle of the tolerance field, the developed methodology for assessing rejects when the scatter zone is displaced relative to the tolerance allowed to form a more differentiated and refined methodological approach to the assessment of losses in disassembly of parts when performing machining operations in repair production.

Introduction of sprouted soybean grain into animal diet provides high protein content in feed, increases its nutrition and digestibility. In the technology of preparation of green vitamin forages based on soybean for seed disinfection before sprouting it is proposed to use UV-irradiation. In order to determine the optimal modes of seed pre-sowing treatment according to the presented methodology, UV-irradiation of soybean seeds was carried out on the previously developed experimental unit of belt type. The treated seeds germinated in a closed box with forced ventilation and a built-in phytolamp. The energy illuminance of UV irradiation and the time of UV treatment of seeds before sprouting were selected as the variable factors, and the length of soybean sprouts on the 5th day of sprouting was selected as the response function. The regression equation describing the influence of UV-treatment parameters on sprout length was obtained from experimental data, and graphical dependences of the response function changes in the variation intervals were plotted. Experimental studies have established the optimal mode of UV-treatment of soybean seeds, providing the maximum value of soybean sprouts. At a specific power of 9 W/m² with UV-irradiation exposure from 30 to 90 s the length of sprouts on the 5th day of sprouting was 120 mm (with 109 mm in control samples). The proposed mode is recommended for pre-sowing seed treatment during sprouting of soybean seeds for vitamin feed for animals.

When growing plants in light culture, particularly effective are energy-saving LED irradiators with long service life, low heat dissipation and small size, as well as an ability to be closely located to the plants and possibility of regulating the intensity and spectrum of illumination. To evaluate the effect of irradiation modes on plants and energy expenditure under these regimes, the productivity of plant products of Japanese cabbage variety Mizuna Red and their biochemical composition were studied. Plants were illuminated by specially designed LED lamps produced by VIM with a dynamically adjustable spectral composition in four channels. Experimental studies were conducted under three radiation modes: continuous (control), pulsed and scanning with a total photosynthetic active radiation of 321 μmol/m²s in the proportion of B:G:R:FR ~ 30:26:38:6. Parameters of aboveground mass and dry matter formation were determined twice on the 15th and 30th days of the growing season. It was found that under the pulsed radiation mode the content of dietary fibres in leaves compared to continuous illumination (control) is 64.3% higher, and ash content – 19.1% higher. The increased content of ascorbic acid and choline has also been noted. The application of the pulsed mode of radiation increased the content of carbohydrates in the tissues of Mizuna Red shoots by 71.4% as compared to the scanning mode.

Lighting of livestock buildings affects the productivity of animals. The system of artificial LED lighting provides the reduction of energy costs in the livestock production at agro-industrial enterprises. A mathematical model is presented to substantiate the parameters of the system of artificial LED lighting of livestock premises. The system of artificial LED lighting should provide regulation of illumination depending on breed and light perception channels of an animal, use control programs of radiation spectrum and illumination duration. The results of mathematical analysis determined that illuminance, uniformity of illumination in livestock premises and power consumption of the LED system depends on the mounting height of lighting devices, as well as the type of light intensity curve, which are determined by the geometric features of LED lighting devices. The emission spectrum is determined by the type of LED light sources, while the duration and periodicity of the daylight hours is provided by the LED software devices. The development of new design solutions of lighting devices will increase the livestock productivity and reduce energy costs.

Power transformers 6‑10/0.4 kV feeding 0.4 kV rural electric networks operate with low load factors. This leads to significant electricity losses. Optimization of the load of 6‑10/0.4 kV power transformers will increase their energy efficiency. To assess the load and loss of electricity in power transformers with a higher voltage of 6‑10 kV of rural electric networks in the Orel district of electric networks (DEN) of the branch of PJSC Rosseti Tsentr – Orelenergo, the authors carried out an analysis of statistical data obtained from operational and technological group dispatcher logs on the load of power transformers 6‑10/0.4 kV of electric networks for 2016‑2022. As a result, it was found that 880 power transformers (74% of the total number) operate with a load factor of less than 20%. Among the 6‑10/0.4 kV power transformers with rated powers of 63, 100, 160, and 250 kVA, the load factor of less than 20% accounts for 72‑77%. It is established that in power transformers 6‑10/0.4 kV of the Orel DEN, annual losses of idle power are 1.8‑2.9 times higher than the short circuit losses. It is revealed that the share of idling losses for different nominal capacities of power transformers 6‑10/0.4 kV is 65‑74% of the total annual electricity losses. The assessment of the load of power transformers is necessary to develop a number of measures to reduce electricity losses in the 0.4 kV electrical networks of the Orel DEN: disconnecting transformers with seasonal loads; replacing underloaded and overloaded transformers with transformers of the required capacity; reequipping the fleet of 6‑10 kV power transformers with modern power transformers with energy efficiency of class X2K2 and higher.

Low efficiency of equipment for heat treatment, disinfection and removal of unpleasant odour of substandard mucous by-products urges the development of an installation that provides for the complex effect of ultra-high frequency electromagnetic field, ozone and bactericidal flow of ultraviolet rays. The paper presents the technology and describes the installation developed by the authors. The installation ensures electromagnetic safety and uniformity of loading according to the penetration depth of the wave. The duration of raw material treatment is matched with the specific power of the microwave generator, the power of the lamps and with the rotation frequency of the compartment disc. The electric field strength has been studied in the CST Microwave Studio program. The developed installation contains a resonator in the form of a flattened spheroid with diameters of the main axes multiple of half the wavelength. Magnetrons are placed on the upper surface of the spheroid along the perimeter. On the inner surface of the spheroid, where there are corona needles, ring electro-gas-discharge lamps powered from pulsed modeled high-frequency generators are uniformly installed along the perimeter through the gap. The source of radiation in the bactericidal lamp is an electric discharge in a mixture of mercury vapour and argon. A fluoroplastic perforated disc is installed at the level of the large diameter of the spheroid, on which mucous by-products are treated. The conducted research shows that the intrinsic factor of quality of the spheroid resonator is 9000. The heat treatment and disinfection of raw materials is most effective at the plant productivity of 50 kg/h, electric field strength of 3 to 4 kV/cm, disc rotation frequency of 0.17 to 0.2 rpm and a specific power of the microwave generator of 1.2 W/g. Power consumption amounted to 6.6 kW, while energy costs were 0.132 kW∙h/kg.

The requirements for the level of theoretical and practical knowledge and skills of agricultural specialists are increasing every year. Chemical subjects form the basis of natural science education of future agricultural specialists. To improve the effectiveness of the educational process, the practice of teaching introduces many different teaching methods. The authors analyzed didactic opportunities of project-based learning and case technology in the context of methodological psychological and pedagogical concepts, in particular, the structure of activity and the logic of personality development. It is established that these methods used in the teaching of chemistry activate all the components of the structure of learning activity: cognitive, value-oriented, communicative, transformative, physical, and aesthetic. The article outlines the ways of using project-based learning and case technologies in the study of chemical subjects by agricultural engineering students. Given as an example is a case study on determining the quality of drinking water by titrimetric and potentiometric analysis methods and selection of a household filter for drinking water purification. The authors dwell on the methodology of performing tasks and define the criteria for evaluating the learning outcomes. Project-based learning and case technologies should meet a number of requirements, have a system of evaluation criteria, certain goals and practice-oriented task, which will enable and motivate students to solve practical problems in their future professional activities.

Intellectual education is an activity aimed at personal development, including such intellectual qualities as competence, creativity, a unique mindset, self-regulation, etc. Intellectual education is an integral part of the education process. The tasks of intellectual education are determined based on students’ intelligence, the level of their compliance with the requirements of professional activity. The authors conducted an empirical study of the peculiarities of mental experience of agricultural engineering students to assess the development of operational characteristics of thinking, determine the relationship between the parameters of intelligence and the level of self-regulation, the correlation of empirical data with the criteria of intellectual education. The study involved 97 students of the Institute of Mechanics and Power Engineering named after V.P. Goryachkin of Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. The results of the empirical study demonstrated a direct relationship between the levels of development of thinking operations and components of volitional regulation of activity. The peculiarity of intellectual development of future agricultural engineers is insufficient formation of a number of intellectual skills, which hinders the formation of intellectual qualities of a professional. To ensure effective and successful engineering activity of graduates (training area 35.03.06 Agroengineering), it is necessary to expand students’ outlook, enrich general mental experience and form a set of professional knowledge, as well as train basic thinking operations.