Harvesting potatoes and vegetable crops coincides with the seasonal peak of precipitation. As a result, the factor complicates the cleaning of marketable products from highly humid soil impurities, which cause the working surface sticking of cleaning devices and decrease their performance. To eliminate this problem, the authors carried out theoretical studies of the separation system working on thermal energy for cleaning the exhaust gases of the power plant. The goal was to determine the design and technological parameters of its individual functioning elements. Relationships were established to determine the separating surface area of slotted cleaning units - a bar elevator and a cleaning sprocket. The analysis helped determine the inter-axial distance between the deflectors, the inter-deflector distance, the inter-conveyor distance, and the translational speed of the rod elevator. The authors obtained the heat flow distribution pattern of exhaust gases on the separating units of root crop and potato harvesters. The study outcomes - the operating modes and technological parameters of the separating system using the heat of exhaust gases for harvesting root crops and potatoes and the heat flow distribution pattern of exhaust gases over the separating surface - will be helpful for further experimental research to improve individual units for harvesting root crops.

Constantly increasing requirements to reduce the energy efficiency of technological processes in crop production call for designing new mechanization means capable of cutting and performing surface tillage in one pass of a unit. The study of modern scientific and patent literature has revealed that the existing individual models of such machines are not used in agricultural production. The work aims to theoretically justify a new hybrid unit designed for simultaneous cutting and soil rotatilling based on the system approach. Theoretical studies showed that the initial requirements for removing low-value and weedy vegetation with simultaneous soil surface rotatilling. The authors considered a model of combining these technological processes, taking into account the requirements for fodder harvesting technology. A provision was made that during soil preparation it is necessary to undercut the vegetation completely with the least energy inputs without reducing its quality for further impacts. In mathematical designing of the working unit, rheological properties of cultivation objects - soil layer and vegetative material - were taken into account. Based on these research outcomes, the authors developed the effective design of a working unit combining cutting with soil rotatilling. Comparative analyses of the agro-energy intensity of the combined operation showed a reduction of specific energy consumption by 10...12% on average.

General recommendations of manufacturers refer, as a rule, to the selection of potato harvesters in terms of operational and design characteristics. Many brands and models of potato harvesters from various manufacturers are consistent with these recommendations. The final choice of an agricultural producer is determined by various quality indicators of a potato harvester. To develop recommendations for selecting a potato harvester, it is necessary to know these indicators and be able to rank them by importance. The article presents the research results related to the development and testing of a methodology for systematizing and ranking quality indicators of potato harvesters. As a result of approbation of the developed methodology, data were collected from 20 farm producers and a Pareto Chart of quality indicators affecting the choice of potato harvesters was constructed. ABC-analysis helped identify the most important quality indicators of potato harvesters for the consumer. The selected indicators were grouped to build a hierarchical tree of properties. To rank the selected quality indicators, the authors proposed to use the method of comparing pairwise hierarchies. As a result of the study, it was found that when choosing a potato harvester, the most significant indicators are the economic ones; they are followed by harvesting quality indicators; the group of operational reliability indicators comes third; and finally we have the group of indicators of the harvester's productivity. The weighting ratios of single indicators obtained as a result of ranking can be used to assess the quality level of potato harvesters using a complex indicator. Taking all these factors into account, agricultural producers will make an informed decision on the purchase of new and used harvesters

Determining the level of permissible grain loss during the operation of combine harvesters is associated with the difficulty of taking a sample from under the working combine harvester according to all the GOST requirements and its further processing. To determine grain losses, the authors carried out theoretical studies of the technological operation of separators and considered the theory of separating the mixture components by specific gravity. The results of previous studies, as well as some information from the relevant research reports were used. Three factors influencing the calculation accuracy were taken into account: the nature of forces acting on individual particles in the separator layer; the aerostatic field exerting an aerostatic influence on the individual particles, which ensures their separation at operating speeds of the separator air flow; the mixing of particles in the sample layer and their separation by specific gravity. It was determined that when the air flow passes through a layer of bulk sample, an aerostatic field is formed inside the layer. It has a large static pressure gradient, in which the particles (grains) are separated only by their specific gravity, regardless of their size, absolute weight or shape. During the separator operation, of air flow has both the aerostatic and aerodynamic effect on the particles, which negatively affects grain separability. As a result of studies, the authors found that the optimal operation mode of the separator has the minimal speed of air flow through a layer of bulk sample, and the air pressure difference at the layer boundaries balances the grain layer.

In recent years, industrial growing of pumpkin has been practeced in the temperate zone. The proportion of varieties and hybrids suitable for cultivation in temperate climates and mechanized harvesting is insignificant. Correct choice of varieties requires the knowledge of the physical and mechanical properties of pumpkin. To determine the varieties with the highest hardness, suitable for cultivation in temperate climates and mechanized harvesting, the authors studied the size and weight parameters (biometric), determined the bark and pulp hardness with a penetrometer and the density of pumpkin fruits by hydrostatic weighing. The research objects included sixteen both domestic and foreign pumpkin varieties and hybrids cultivated in a mechanized way: hard-barked (Spaghetti, Pivdennaya, Mozoleevskaya); large-fruited (Pastila Champagne, Barn, Marine Di Chioggia, No. 119-C); nutmeg (Butternut, No. 19-Pgv, Muscat of Provence, Beauty, Vitamin, No. 13-M, No. 26-Mch, No. 28-Ig); fig-leaved - No. 4480. The studies were carried out in the conditions of the Moscow region. Cultivation technology, setting up field experiments and statistical processing of the obtained results were carried out according to the standard method of B.V. Dospekhov. The research was carried out from 2016 to 2020. Based on the studies, the authors stated that the hard-barked pumpkin of the Spaghetti variety (1.20 and 0.80 kg/mm²), large-fruited - Pastila champagne (1.02 and 0.79), nutmeg - Muscat of Provence (1.10 and 0.65) and fig-leaved specimen No. 4480 (1.25 and 0.97 kg/mm²) feature the highest strength indicators. The total number of pumpkins is subject to the law of distribution in terms of size and weight, the weight of fruits on yearly average ranges from 1.56 to 3.3 kg. The obtained results provide enough grounds to recommend these varieties for cultivation in a temperate climate and mechanized harvesting.

Technological processes of primary processing and storage of livestock products require large volumes of low-potential thermal energy. One of the effective ways to preserve the high quality of milk, reduce the energy consumption of primary processing and storage of livestock products is the use of alternative energy sources. The author has analyzed systems for primary processing and storage of milk based on the use of natural cold, vacuum and thermoelectric modules. The article shows the advantages of such systems as compared with traditional ones and gives the classification of equipment using natural cold. It is noted that when using natural cold, the cost of electricity for cooling milk is reduced to 10...12 kWh/t, and when using a hybrid vacuum-evaporation plant - up to 15...18 kWh/t. The article presents a technological scheme of a thermoelectric installation for milk cooling and pasteurization and recuperative heating of washing water on farms with milking robots. Based on the performed analysis the author makes recommendations on the use of alternative energy sources for milk pre-cooling on farms with milking robots. It is established that the use of alternative energy sources provides for environmentally safe, energy-saving and reliable primary processing and storage of livestock products in the places of its production, and contributes to a significant reduction in losses and preservation of high quality. Studies have proved the effectiveness of using combined cooling and storage systems for livestock products using natural cold in combination with thermoelectric, vacuum, and ground cooling

When analyzing raw milk properties, we should take into account the complexity and ambiguity of the “bacterial contamination” criterion. The authors evaluated the infl uence of physico-chemical and microbiological parameters of milk on its contamination over a year period. Milk testing protocols for 2020 were used as a source of information. The values of acidity, the number of mesophilic aerobic and facultative anaerobic microorganisms (CMAFAnM), the number of somatic cells, the proportion of protein and fat, and the density of milk were studied. To assess the infl uence of environmental parameters, the authors took ionto account the values of air temperature and humidity at the moment of sampling. Sampling was carried out according to GOST 26809.1-2014 “Milk and dairy products. Acceptance rules, sampling methods, and sample preparation for analysis”. The research was carried out on three dairy farms of the Knyaginino district of the Nizhny Novgorod region. They included a dairy farm with tie-up housing for 200 heads with milking in a linear type milk pipeline; a dairy farm with loose housing for 400 heads with milking in a herringbone type milk pipeline; a dairy farm with combined (tie-up and loose) housing for 450 heads with milking in a linear-type milk pipeline. The lowest indicator of QMAFAnM (total viable content) was noticed in March, and the highest – in November. The correlation analysis showed that the greatest infl uence of the studied factors on the level of bacterial contamination is exerted by the number of somatic cells (Pearson correlation coeffi cient R = 0.71 with a confi dence probability P = 0.0619). The authors suppose that this situation may result from improper hygienic condition of the udder, equipment, and premises. There was a weak infl uence on the level of bacterial contamination of milk density (R = –0.18 at P = 0.096) and ambient air temperature (R = –0.18 at P = 0.095), which may be result from insuffi cient cooling of milk before transportation.

One of the technologies for obtaining and storing high-quality silage and haylage is the use of silo towers. The authors propose to manufacture silo towers from high-strength and corrosion-resistant steel sheets, coated with glass enamel, which has a lower coefficient of sliding friction than steel and concrete, as well as high resistance to aggressive environments. The aim of the study was to determine the properties of the glass-enamel coating of steel parts for the manufacturing of tower-type storages. A glass-enamel coating from a frit of glass-enamel brand MK-5 was applied to prepared sheets of steel 09G2S using a spray gun. The total thickness of the enameled coating ranged from 200 to 350 nm. Steel sheets were baked at a temperature of 850°C for 30 minutes. The thickness of the enamel coating was determined with an Olympus GX51 microscope. The roughness was determined using a TAYLOR HOBSON Surtronic 25 profilometer. The adhesive properties of the coating were studied using a Positest AT-M adhesive meter. Each test piece was tested twice. The tests were carried out on a sheet of 0.06 m². The coefficient of sliding friction was determined on an adapted test bench. Laboratory tests with silage mass were carried out according to the developed methodology. Studies of the steel surface with a glass-enamel coating showed that the average thickness of the enameled layer was 690 nm, the roughness was 0.01 urn, and the adhesion was 5.25 MPa. The sliding friction coefficient of sliced plant materials on the enameled steel surface was 0.15, which is 2.6 and 3.2 times lower than that of non-enamelled steel and concrete, respectively. The authors have made conclusions about the possibility of using steel 09G2S in silo towers as a suitable sustitute for steel 65G and the sufficient efficiency of the chosen enameling technology.

Searching for new eff ective ways of increasing the wear resistance of power transmissions and improving their durability, the authors propose a device for enriching the lubrication system of power transmissions with copper-alloying elements. The tribochemical processes have been studied and the components of the lubricating composition have been selected to provide for the self-organized selective transfer in the “steel-steel” friction couples accompanied by the formation of a servovit fi lm. The authors developed a utility model for enriching the lubricating system oil with copper-alloying elements for power transmission. For testing the eff ectiveness of the proposed additive and the method of forming the servovit fi lm during operation, a roller test bench was used. It provided for synchronous measurement of the wear rate and the friction force moment during the whole experiment without disconnecting the friction zone. The friction zone (test contact) was formed by the cyclic surfaces of a roller with a diameter of 70.0 ± 0.1 mm made of steel 45 (HRs 50) and a homogenized pad with a radius of 35.0 ± 0.1 mm and dimensions (plan view) of 2.01 mm (along the sliding line) and 7.27 mm (across the sliding line). The friction area was 0.1461 cm2 . A set of normal forces: 730; 925; and 1130 N – was experimentally determined to ensure that there was no seizure. The shaft speed of 100 min-1 (a linear velocity of 0.37 m) was experimentally chosen under the condition of guaranteed absence of the hydrodynamic lubrication mode. The presented method of cladding additive production is easily implemented in the transmission units and also prevents the sedimentary instability of the lubricating composition. The device for enriching the lubricating system oil with copper alloying elements in the process of operation provides for a stable and self-organized mode of selective transfer. The results of tribological studies have shown the high effi ciency of the cladding additive – the wear rate in the range of the normal force of 720 to 1130 N has reduced in 2.8…7 times.

The main methods of surface hardening during electromechanical processing (EMP) include finishing-hardening electromechanical processing (FHEMP) and electromechanical surface hardening (EMSH). EMSH, as compared with the FHEMP modes, features a slow processing speed (0.6...1.4 m/min), a long contact width of up to 5 mm, a significant electric current strength of the secondary circuit - 1200...3000 A. The article presents a three-dimensional model for predicting and determining the temperature fields of the hardened layer of U8 steel bushings during EMSH made in the ANSYS Workbench program. The authors carried out finite element modeling of the EMSH process consisting of successive transient structural strength analysis and transient thermal analysis. During EMSH, the thermomechanical cycle "heating - keeping - deformation - cooling" is carried out in the closed contact zone of the tool and the workpiece in hundredths of a second. It was found that during EMSH a temperature gradient is formed along the depth of the hardened zone as there is intensive cooling of the surface layer heated to 1559°C, as a result of heat removal by the underlying metal layers. After EMSH a fine-dispersed martensite is formed in the hardened zone. The study results are useful for developing the EMSH processing technology of the surface layer of bushings made of U8 steel based on the hardening mode with the following parameters: hardening speed of 1.2 m/min, the current strength in the secondary circuit of 1600 A, the secondary circuit voltage of 3 V; the width of the contact electric effect of 4 mm; the pressing force of the tool roller of 400 N.

3D printing technologies are used to make spare parts for agricultural machinery. Among other things, the use of 3D printing in this area is restrained due to insufficiently high mechanical properties of the resulting parts, which occurs due to poor adhesion between plastic layers during printing. To eliminate this problem, the author proposes to carry out vacuum impregnation of 3D-printed parts in epoxy resin. The aim of this work is to assess the change in the tensile strength and the impact strength between the 3D-printed polymer samples and the 3D-printed samples impregnated in a polymer compound, as well as to reveal the behavior of these properties depending on the structure of the 3D-printed frame. The frames of the samples were made of polylactide on a 3D printer using the FDM technology with different percentages of filling (20, 33, and 50%). During the printing process, layers of plastic were stacked in longitudinal and transverse directions relative to the sample axis. Subsequent impregnation was carried out in a vacuum chamber. As a result of the tests, it was found that for any geometry the mechanical properties of the impregnated samples are higher than those of the non-impregnated ones, and the anisotropy of the strength properties for the impregnated samples with different directions of layers was found significantly reduced (the anisotropy coefficient decreased from 2-5.5 to 1). The material destruction type is fragile. For samples of the longitudinal type, an increase in mechanical properties is observed with an increase in the percentage of 3D printing filling. On the contrary, samples of the transverse type have a tendency to decrease their level of properties. In this regard, for structures experiencing loads in different directions during operation, it is recommended to use an intermediate ratio between the base plastic and the impregnating composition (33:77%, respectively).

The main problem of modern internal combustion engines at present is the growing shortage of fuel and the increase in environmental safety requirements. To solve this problem, the authors suggest adding alcohol to diesel fuel. This additive - ethanol or methanol - will help reduce harmful emissions of combustion products into the atmosphere and increase the efficiency of the internal combustion engine in the main operating modes. The method of feeding the mixture into the combustion chamber will have a great effect on the combustion process of the fuel-air mixture with alcohol. There is a large number of ways to supply alcohol to the engine, but their comparative characteristics have not been fully studied yet. To evaluate various methods of introducing alcohol into a diesel engine, an experimental installation including an electric brake balanced machine and a diesel engine has been developed. The installation allows the diesel engine to be loaded to the required torque value and makes it possible to record the main mechanical parameters of the engine. In this study, the authors considered the supply of alcohol in the diesel engine cylinders with two methods: in the form of an emulsion with fuel and with air on the intake stroke (in the intake manifold). The unit will quantify at different engine operating modes and the proportion of alcohol delivered both as an emulsion and with air. The research will help assess the feasibility of using alcohol additives and adjust the theoretical justification of the processes occurring during the combustion of the fuel-alcohol mixture in the cylinder

The development of technical means of production contributes to the improvement of technological modes of the economy. To establish trends of updating technical means and form technological modes of the country’s economy, and their interrelation and interdependence, the author has identified and characterized key periods of formation and development of technology, identified key factors of formation and improvement of the technological modes of production, and advanced technical and technological development trends of modern production. It has been established that the acceleration of scientific and technological progress under modern conditions is accompanied by the implementation of scientific achievements in the vital activity of society in the process of the gradual transfer of individual human functions and complex production operations to technical means, transformation of technologies and machinery. Ultimately, machinery is transformed into a machine system. The perfection of the machine system as a whole and coordinated change of each link provide for automation and digitalization of production at the qualitatively new technical and technological level, realizing progressive, innovative methods of organization and management of production. The evolution of technology stimulates the activities of the scientific community in the technical and technological segment, and promotes the formation of new technological modes in the national economy. It has been determined that in the process of the historical improvement of production, innovative technical means and technologies become the “driver” of the emergence of new technological modes. A change in the technological mode results from technological progress, accompanied by radical changes in the development of productive forces, renewal of the workforce with competences that meet the requirements of the new technological mode. The country’s transition to the sixth technological mode will ensure the rapid development of all spheres of social production, and at the same time will increase the profitability and competitive advantages of domestic agricultural production.