Currently, the Russian agricultural sector is experiencing an acute shortage in tractor power means, especially, general-purpose tractors. The production of a domestic universal tractor and the justification of its compatible machine train requires identifying the options of its coupling with implements, taking into account the attachment mounting capacity of its hydraulic systems and the bearing capacity of the running gear. The study aimed to assess the load capacity of a general-purpose tractor of the integrated design (class 2-3 LTI-162.5) for various coupling options of agricultural machinery and operation in the inter-row distance of various crops. The analysis of the maximum ground pressure indicator of the LTI-162.5 chassis system showed its dependence on the vertical load on the wheel, the tire size of the wheel, and the internal tire pressure. As a result of the research, the permissible mass of agricultural implements attached to the front and rear mounting units was found based on the condition of the permissible load on the LTI-162.5 tractor movers on all declared tire sizes. In addition, the study established its compliance with the technical specifications for the load capacity of the mounting unit. It was determined that the coupling of the LTI-162.5 tractor in both single-operation and combined versions is ensured without losing the unit controllability in the short-range transport position on all tire sizes, within the limits of permissible loads, and does not require additional ballasting with loads. When coupling the LTI-162.5 tractor in a combined version, an attachment weighing 1,900 kg can be mounted on the front mounting unit, while the rear mounting unit can take a weight of up to 2,600 kg, which is limited by the load capacity of the tractor’s attachment systems. At the same time, in the short-range transport position, the unit can be controlled without additional ballasting. The results obtained will make it possible to equip a general-purpose tractor with various implements and a train of machines.

Methodology for the theoretical determination of the parameters of the pneumatic system for the uniform distribution of fertilized hydrogel when planting potatoes under irrigation can reduces the number of watering operations. To determine the pneumatic system parameters, the authors took an example of the pneumatic system of a potato planter that can evenly distribute granules of hydrogel and fertilizers in the soil. The Bernoulli equation describing the continuity of a liquid of gas flow was taken as the theoretical basis for the determination of the parameters of the pneumatic system. Based on the obtained relationships, the authors determined the values of air velocities in various sections of the pneumatic system, found the dependencies of overpressure in the system, as well as the parameters of the injector and the radius of the nozzle for mixing fertilizer granules and hydrogel. To solve the obtained complex dependencies, use was made of a developed algorithm and the Mathcad software. It was established that the pneumatic system introducing hydrosorbent and a fertilizer mixture below the potato-planting furrow should make optimal pressure from 0.22 to 0.28 N/m³. In this case, the nozzle radius varies between 3∙10^-3 m and 3.5∙10^-3 m, the average value of the radius being 3.25∙10^-3 m. The obtained values can optimize the potato planter operation.

The use of a contemporary sowing machinery unit – Nardi Dora (DORA 600) air drill for sowing wheat at the Tselot farm in Eritrea revealed a wide range of characteristics that trigger the assessment of the movement precision of the unit. They include uneven inter-row distances and visible over-seeded and skipped zones. Inaccurate seeding results in repeated and missed (unsown area) sowing patterns that lead to the rise of monetary expenses owing to the overconsumption of seed and fuel while lowering production. The study sought to assess the rate of repetition and rate of miss operations to evaluate the sowing precision of the Nardi Dora Air drill and compare it with the modern automated systems. The experiment was conducted in Eritrea on a wheat-sown area of around 107 ha. Sowing precision evaluation was based on the tracked routes on a mobile phone using the Locus GIS offline land survey application version 1.17.0. Deviations of the actual working width from the required values were determined from the track records. The movement precision of the unit was compared with the auto-driving systems of the modern driving systems: Autopilot, Autopilot™, AutoTrac™, SteerCommand with GPS7500, AGI-4, GPS PILOT, Autosteer, Auto-Steer, F100 Auto Steer System and IntelliSteer™. An operating speed range of 10-12 km/h provided an acceptable range of the working width. Statistical analysis showed a high level of superiority of GPS-guided seeders over the conventional sowing units. Consequently, the authors recommend using advanced automated technologies in Eritrea.

The unsatisfactory condition of the majority of soil resources of the country is due to the use of agrotechnical methods and technical means of mechanical impact on soil horizons. Energy-consuming moldboard plowing with a soil layer turnover results in a vertical mixing of heterogeneous soil layers and their exposure to photochemical radiant energy of the sun. As a result, aerobic and anaerobic bacteria, microorganisms and mesofauna adapted to live in the soil at a certain depth die; natural processes of humus formation and accumulation are disturbed, soil fertility decreases, soil horizons are overconsolidated and destroyed. This technology results in unproductive losses of organic carbon up to 50%. In order to develop technological processes and technical systems of soil tillage, providing an integrated transition to the natural resource management of agricultural lands, the author analyzed trends in the development of soil tillage techniques, regularities of plant physiology, plant life and soil biocenoses. The studies have established that in-soil treatment with pulses of compressed air by means of pneumatic hydrodrills immersed in the soil provides optimal loosening, aeration and subsequent rational supply of agrochemical solutions into root-inhabited layers. At the same time, this operation stops the processes of degradation and erosion of agricultural lands and increases the humus content in root-inhabited soil layers. The developed method (Patent No. 2830861 of the Russian Federation) and the innovative design of a pneumatic hydrodrill provide conditions for the online scanning of a soil horizon for 10-15 s and express analysis of soil characteristics. Based on the results obtained, we can supply the necessary dose of appropriate reagents to the soil. Transition to the innovative principle of soil treatment reduces significantly the total specific energy inputs.

Automation of a mini feed mill will eliminate the human factor in the management and control of the feed production process. The authors conducted research to improve the efficiency of the mini feed mill through automatic control and regulation of grain crushing. Automation of the control systems for grain crushing is feasible in case of mechanized regulation of grain material supply into a pneumatic hammer mill. The authors proposed a model for a remote automatic control system for the loading device (ejector) of a pneumatic hammer mill. The proposed design takes into account the specified mass of the component according to the feed formulation, the current consumed by the hammer mill, and the comparison of image datasets of the specified components with the video stream of raw materials entering the mill. To implement the proposed model, they developed an ejector with remote control of the air suction window flap via a “Bowden cable”. Experimental testing of its functionality has shown a relationship between the ejector’s performance and the area of the air suction window with an approximation reliability of 0.9985. As a result, the research has proven that the proposed technical solution is capable of automatic regulation of the performance of a pneumatic hammer mill. There are further plans to develop a servo drive for smooth movement of the “Bowden cable” in both forward and reverse directions, as well as instant shutdown of material supply upon reaching the specified component mass or in case of emergency.

Wet granulation of plant-based raw materials is necessary to prepare granulated feed of small diameter for fish and their fry. A basket granulator is a feasible solution for this process. The authors performed experimental studies to establish rational values of factors of wet granulation, providing its low specific energy intensity. Fish fry feed from plant material was pelleted in a basket granulator to get pellets with a diameter of 2 mm and a length of 4 mm. Three most significant factors affecting the process of wet granulation of plant-based raw materials and specific energy intensity of granulation were established after preliminary studies: moisture content of raw materials, grinding modulus of raw materials and rotation speed of the granulator’s operating parts. Specific energy intensity of granulation was accepted as a criterion for optimizing the wet granulation process of plant-based raw materials. The experiment was conducted at the following values of factors: a feed moisture content of 30, 35, and 40%; its grinding modulus 0.82, 1.24, and 1.66 mm; a rotation speed of granulator operating parts of 40, 50 and 60 min^-1. The obtained regression equation adequately describes the process of wet granulation. The established optimal values of specific energy intensity of wet granulation of feeds, equal to 1.9 to 2.3 kW·h·t^-1, are achieved at the following rational values of factors: a raw material moisture content of 40 to 42%; a grinding modulus of 1.6 to 1.7 mm; a rotation speed of the granulators operating parts of 60 to 62 min^-1. Obtaining waterproof granules at the minimum specific energy intensity of granulation is possible on condition that the specified values of factors are observed.

Increased environmental requirements for tractor diesel engines and rising prices for petroleum fuels urge the search for alternative fuels to replace traditional ones, partially or completely. Peanut and palm oils are the most competitive and affordable solutions. The authors conducted the study to assess the possibility of using peanut and palm oils as additives to diesel fuel in tractor engines. Experimental studies were conducted on a D-120 air-cooled tractor engine using mixed fuels with a composition, the physicochemical properties of which were similar to the base diesel fuel. In the first series of experiments, the mixed fuel contained 40% peanut oil, 30% diesel fuel, and 30% kerosene by volume. In the second series of experiments, diesel fuel was mixed with 10 and 20% palm oil. The authors analyzed the effect of oils on fuel consumption, specific effective fuel consumption, and the concentration of toxic components in exhaust gases using pure diesel fuel as a standard. It has been experimentally established that the addition of 40% peanut oil leads to an increase in fuel consumption of 8 to 10% and the concentration of incomplete combustion products (hydrocarbons increases by 25 to 32%, CO – in 1.55 times). The concentration of nitrogen oxides and soot decreases by 10 to 25% depending on the mode. With the addition of 10% palm oil, fuel consumption increases by 0.1 to 0.2 kg/h, with 20% – by 0.2 to 0.3 kg/h. At low and medium loads, a 20% oil addition led to a decrease in the hydrocarbon content of 42% and an increase in CO of 37 to 49%. At high loads, the content of hydrocarbons decreased by 17% and nitrogen oxides by 21% (4550 ppm), the concentration of CO increased in 6-8 times (up to 65 ppm). The soot content in exhaust gases with a 10% additive is reduced by 20 to 30%, with 20% – by 35 to 45%. The study proved that fuel additives – peanut and palm oils – can be used in a diesel engine, but it is necessary to adjust the viscosity and ignition delay period of the fuel.

Volatile corrosion inhibitors, penetrating into gaps and adsorbing on the surface, provide better protection of metal products than other types of inhibitors. In particular, the anticorrosive effect of amino alcohols is due to the formation of complex compounds between nitrogen or oxygen and the metal ion. Boron esters form hard-to-solubilize protective films on the metal surface. Ethanolamine with boric acid can form various products, but there have not been any comprehensive studies on their properties as volatile corrosion inhibitors. The aim of this study was to synthesize products of interaction between ethanolamine and boric acid and to analyze anticorrosion properties of the obtained substances on ferrous and non-ferrous metals. To determine the composition and conditions for obtaining an inhibitor with high anticorrosion properties, the authors conducted experiments with a variable ratio of reagents and reaction temperature. As a result, they developed methods for obtaining volatile corrosion inhibitors. Four products were synthesized: ethanolamine and boric acid adduct, aminoethylborate, di(aminoethyl)borate and tri(aminoethyl) borate. The anticorrosion properties of the inhibitors were checked in accelerated tests. The evaluation of the protective ability was determined by gravimetric method, after which the corrosion rate, corrosion inhibition coefficient and degree of protection were calculated. Anticorrosive effect of volatile corrosion inhibitors was tested on specimen plates made of steel St3, copper M1 and alloys D16, L63. As a result of tests of the obtained inhibitors, di(aminoethyl)borate showed the best protective properties. Its maximum protective effect of 89.9% was observed on steel, the minimum one of 30.3% – on copper. The obtained results will significantly increase the degree of protection of ferrous and non-ferrous metal products from corrosion during operation, transportation and storage while reducing the cost of their maintenance.

Durable operation of the “shaft-seal” joint in agricultural machines affects their service life. The analysis of factors affecting the durability of the “shaft-seal” joint has revealed the need to study the quality of the initial tension range in the “shaft-seal” joint and their compliance with the parameters of dimensional interchangeability, preset in the design documentation. The research purpose is to evaluate the probabilistic characteristics of the dispersion of joints of the inner diameter of the seal and the outer diameter of the flange of the transmission gearbox YAMZ-239. The study involved 100 flanges and 100 seals 1.2-100×125-12. The diameters of shaft ends were measured using a lever bracket SRP 100-0,001. The inner diameter of the seals was determined with a DIP-6 instrument and the NIIK-890 system. The conducted estimation of the dispersion parameters of the surface dimensions of the gearbox output shaft of YAMZ-239 under the 100h10 seal showed that shaft manufacturing provides a technological accuracy above the required level with satisfactory adjustment. However, there is a growing probability of a correctable defect. The study of the inner diameter of the seals showed that the accuracy of forming the inner diameter of the seals is good, the process adjustment is satisfactory; there is a slight shift towards a probability of an uncorrectable defect, but the defect itself is absent. The conducted analysis of tension dispersion showed that the probable percentage of defective joints, as a durability indicator, was 0.01%. The study found that the accuracy of manufacturing the “flange-seal” joint parts meets the specified requirements. The problems with the lubricant leakage from the seals should be solved based on the parameters of wear resistance of these parts, as well the wear analysis of the influencing dimensions that form a dimensional chain. In this chain, the initial closing link is the deviation from alignment and radial runout of the shaft in relation to the seal diameter.

One of the effective ways to restore the serviceability of the “shaft-seal” joint is the use of thin-walled repair bushings. When installed on shafts, they restore the joint tightness without disassembling the unit in shortest time and field conditions. The team of authors have produced thin-walled repair bushings with a wall thickness of 0.25 mm. They have made research to choose a surface hardening method for thin-walled bushing to achieve a microhardness of above 21,000 MPa. This value exceeds that of quartz abrasive and aluminum oxide, which are the main components of dust. Having analyzed the methods of surface hardening, the authors approved the applicability of electrolytic chromium plating and physical vapor deposition of coatings (the PVD method) for thin-walled repair bushings. Thin-walled bushings were surface hardened by electrolytic chromium plating (Хтв 21 (Cr hard)) at a temperature of 45 to 55°C, titanium nitride (TiN) coating was obtained by the PVD method at a temperature of 200 to 450°C. The coating thickness was measured with a Konstanta K5 electromagnetic thickness gauge used for protective coatings. The microhardness of the hardened surface was determined with a PMT-3M device. The roughness of hardened working surfaces of thin-walled repair bushings was measured with a MarSurf M400 profilometer (a surface finish gauge). After surface hardening of thin-walled bushings, the thickness of chrome coating was 21to 30 microns, and that of titanium nitride – 4.2 to 5.2 microns. Electrolytic chromium plating resulted in a microhardness of bushing surface of 11,000 to 12,000 MPa, while the PVD method provided a microhardness of 18,900 to 21,700 MPa. The profile diagram of the hardened working surface of a bushing showed that the roughness value decreased by one degree of fineness. The research results have proved the applicability of the chosen methods of hardening thin-walled repair bushings with a thickness from 0.25 mm.

It is a common practice to treat soil against pests and pathogens of agricultural crops to ensure its disinfection using alternative methods, which include electromagnetic radiation of various spectrums: ultraviolet (UV), infrared (IR), microwave (microwave), and high frequency (HF). The authors have developed an IR irradiator to disinfect soil mixtures placed in a thin layer on a conveyor belt. In order to optimize soil mixture disinfection with IR irradiation, the task was set to obtain regression equations of the irradiator operation modes. The authors studied different modes of the IR irradiation of soil mixture layer placed on the conveyor belt at the layer thickness of 10 to 50 mm, the IR irradiator hanger height of 50 to 250 mm, and the IR irradiator power of 9.5 to 47.5 W. The authors studied three main relationships describing the working process. 1. Dependency of soil mixture temperature on layer thickness at the constant IR irradiator power, constant height of the IR irradiator hanger, and constant speed of the conveyor belt. 2. Dependency of the travel speed of the conveyor belt on the hanger height of the IR irradiator at its constant power, constant soil mixture thickness, and fixed temperature range (T = 95±5°C). 3. Dependency of the conveyor belt travel speed on the IR irradiator power at a constant height of its hanger, constant soil mixture thickness, and fixed temperature range (T = 95±5°C). The obtained regression equations Obtained regression equations with an approximation accuracy of 0.976 to 0.999 can facilitate the calculation of the operating modes of various-size irradiators, optimizing the disinfection of soil mixtures with IR irradiation and integrate it with an automatic control system.

When predicting power consumption and power shortages in rural power grids, it is necessary to take into account the seasonality of emergency outages. However, the necessary data on the effect of seasonality on the reliability indicators of power grids are not available. Moreover, the regulatory and technical documentation fails to cover the issues of seasonality in the electric power industry. The study aimed to determine the seasonality coefficients for the failure flow and restoration time, taking into account the causes of outages in rural 0.4 kV power grids. Using statistical data from one of the central regions of Russia for the period between 2018 and 2023, the author identified the most significant causes of emergency outages in rural 0.4 kV power grids: consumer-caused outages, fuse blowing, wire splicing, wire breakage, and others. For each cause, the seasonality coefficients for the flow of failures and restoration time were calculated. The study found that the highest probability of emergency outage falls on the period from May to August; the seasonality coefficient for this period ranges between 1.15 and 1.83. In other periods, the coefficients are lower: from September to December – 0.71 to 1.06, from January to April – 0.54 to 0.67. The highest value of the seasonality coefficient by the restoration time was recorded in the period from May to August (1.27 to 2.03), the minimum – in January-February (0.44 to 0.52). Taking into account the seasonality coefficients for specific reasons will make it possible to forecast indicators of power supply reliability and plan better and more efficient measures to improve power grid reliability.