OPTIMIZING THE PIPELINE DIAMETER OF A CIRCULAR SPRINKLER ACCORDING TO THE MINIMUM ENERGY CONSUMPTION CRITERION

The authors have determined the conditions for the eff ective use of modern electrifi ed circular sprinklers in the central part of Russia. Their designs are chosen depending on the agrotechnical requirements for irrigation, including the change in the diameter of the water distribution pipeline. However, when the diameter of the pipeline changes, the load on the electric drive of the support trolleys of the sprinkler changes too, which leads to a corresponding change in energy consumption. In turn, this also changes the load of the water supply pump. The paper sets the task of determining the optimal change in the diameter of pipelines according to the criterion of minimum energy consumption, taking into account a number of assumptions. The authors have analyzed the relationship between the change in the load on the electric drive of the sprinkler support trolley and the change in the diameter of one sprinkler section pipeline. It has been found that a decrease in the diameter by 27% (for example, the transition of the diameter of 219 mm to the diameter of 159 mm) leads to a decrease in the load on the electric drive by 38%. However, this also leads to an increase in the head loss in the water supply pump motor and, respectively, to an increase in the load and energy consumption by 0.8…3.8%. The eff ect is initially obvious, but the power of the electric motor of the water supply pump is 10…25 times higher than that of the electric motor of the sprinkler support trolley. Based on the similarity coeffi cients of the irrigation components (water supply and water distribution), the relationship beteween the total energy consumption and the change in the diameter of the water distribution pipeline has been obtained. By diff erentiating the obtained function, the dependence of the value of the optimal diameter for specifi c operating conditions is also obtained. Graphs of the relationship between energy consumption and the change in diameter have been determined, taking into account some restrictions: pump supply, static pressure, and the number of the sprinkler sections.

ENGINEERING ANALYSIS OF THE THREE-PHASE SHORT CIRCUIT MODE IN THE 10 KV ELECTRIC NETWORK TAKING INTO ACCOUNT THE INFLUENCE OF LOAD CURRENTS

The load current aff ects the value of the short-circuit current in the electric network and, consequently, the voltage value. In some cases, this infl uence must be taken into account for the correct choice of switching devices, remote monitoring the operating modes of electric networks, and determining the modes. It is possible to disconnect loads connected through magnetic starters and contactors. Failure to consider the infl uence of the load current can lead to an incorrect interpretation of the identifi ed grid operating modes during remote monitoring and, as a result, incorrect dispatcher’s decisions. In addition, it is also insuffi cient to specify the choice of switching devices in the 10 kV feed network. The article describes a method for analyzing the three-phase short circuit mode in a 10 kV feed network, taking into account the infl uence of load currents. The method is exemplifi ed by the case of an actual electric network – the 10 kV ring feed network containing reclosers and receiving power from diff erent sections of lowvoltage buses of the “Kulikovskaya” 110/35/10 kV substation, belonging to the Branch of PJSC «DGC of Center”-“Orelenergo.” For this network, the values of the three-phase short-circuit currents at points with diff erent distances from the substation buses have been determined. The authors have fi guredout the values of the load currents and their shares in the total short-circuit current. The voltage values at different points of the network in the case of short circuits have also been determined. The research proves that the effect of the load current on the total short-circuit current should be taken into account for the case of remote short circuits.

FEATURES OF USING A GROUND LASER PROFILER TO ASSESS THE QUALITY OF SOIL CULTIVATION ON AGRICULTURAL SLOPE LANDSCAPES

The authors analyze an extensive set of data for measuring the daily surface profi le of the cultivated soil to assess its agrotechnical parameters. The research was carried out on a small agricultural catchment area of the Orininsky rural settlement, which is located in the Morgaushy district of the Chuvash Republic. Three agricultural fi elds were selected, ranging from 25 ha to 53 ha. The studied areas were cultivated in various ways: plowing with harrowing, disking the soil and winter plowing. The profi les of the studied elementary sections were measured using a developed ground-based circular laser profi lometer. Data on the state of the profi le were used to determine the main agrotechnical parameters - clumping, cloddiness, surface slope, and deviation of the travel trajectory of a machine and tractor unit from the line of equal height. A software tool for processing and analyzing data received from sensors has been developed. The results established that the deviation of the projection of the greatest elevation line changes (measured by the slope) from the travel trajectory of a unit with an angle of 62, a slope of 6.5, and in a quantitative size distribution soil aggregates of 1…4 inches in diameter prevail. The weighted average diameter of the clods was 3.99 cm. The research results have determined the use of recommend methods for stating the agrotechnical parameters of the daylight surface to evaluate the cultivated soil in accordance with agrotechnical requirements.

TEACHING CAPABILITIES OF ROBOTIC VR- CONSTRUCTORS IN THE TRAINING PROGRAMS OF AGRICULTURAL ENGINEERS FOR THE DOMESTIC FARM INDUSTRY

The paper discusses the didactic advantages and features of the use of such immersive technologies as “virtualconstructor” in the practical training of BSc students (training area 35.03.04 “Agricultural Engineering”) for the domestic farmindustry. VR-constructors are software products that fully emulate a virtual environment with a 360° view, the distinctive featureof which is to maximize the possibilities for interacting with virtual objects in terms of their study, movement and transformationof the object system. As applied to the training of agricultural engineers such systems of virtual objects can be represented by properlydesigned training mechanisms of engines, various irrigation systems in hydroponic installations or a specifi c soil profi le with itsindividual horizons. The authors conducted analysis of scientifi c literature, refl ecting the practice of the application of virtualreality technology to be used in the training of university students. The study has revealed the lack of precedents comprehensiveintroduction of VR technology as an eff ective learning tool in higher agricultural education in Russia and abroad. After conductingthe experiment based on a number of expert assessment methods, two VR software products of the “VR-constructor” type wereidentifi ed, which are recommended for implementation in course syllabi for BSc training in agricultural engineering in: “3D-cardfi le of soil sections” and “VR-atlas of agricultural machinery”. The study of the teaching capabilities of these curricula has statedthe need to change the traditional roles of the teacher and the student and the necessity for further scientifi cally-based introductionof university course syllabi of various levels to train more competitive and highly qualifi ed personnel for the innovative agriculture of Russia.

OPTIMIZATION OF GAS-DIESEL ENGINE REGULATION AS A METHOD OF IMPROVING ITS ECOLOGICAL CHARACTERISTICS

The paper shows some ways to improve the environmental characteristics of a diesel engine using gaseous hydrocarbon fuel and operating the engine in a gas-diesel cycle mode. Some possibilities to reduce toxic components of exhaust gases in a gas-diesel engine operating on liquefi ed propane-butane mixtures have been studied. Experiments carried out in a wide range of load from 10 to 100% and speed from 1400 to 2000 rpm showed that the gas-diesel engine provides a suffi ciently high level of diesel fuel replacement with gas hydrocarbon fuel. The authors indicate some eff ective ways to reduce the toxicity of exhaust gases. The engine power should be adjusted by the simultaneous supply of fuel, gas and throttling the air charge in the intake manifold. This method enriches the fi rst combusting portions to reduce nitrogen oxides and maintains the depletion of the main charge within the fl ammability limits of the gas-air charge to reduce carbon monoxide and hydrocarbons. The authors found that when the engine operates in a gas-diesel cycle mode, the power change provides a decrease in nitrogen oxide emissions of gas-diesel fuel only due to gas supply in almost the entire load range as compared to the pure diesel. At high loads (more than 80%) stable engine operation is ensured up to 90% of diesel fuel replaced by gas. Even at 10% of diesel fuel used the concentration of nitrogen oxides decreases by at least 15…20% as compared with a diesel engine in the entire load range. However, there is an increased emission of hydrocarbons and carbon monoxide in the exhaust gases. Further experimental studies have shown that optimization of the gas diesel regulation can reduce the mass emission of nitrogen oxides contained in exhaust gases in 2…3 times and greatly reduce the emission of incomplete combustion products – carbon monoxide and hydrocarbons.

EXPERIMENTAL STUDIES ON THE DEVELOPMENT OF AN AUTOMATED SYSTEM FOR REGULATING THE SOIL DENSITY USED IN A SEEDING MACHINE

Research on the development of an automatic control system for the rolling-in working units is aimed at establishing the reliability and analytical relationships, determining the quality indicators of work in real conditions of the rolling-in working units of a seeding machine, and checking the patterns obtained in the fi eld and identifi ed theoretically. Research on the development of an automatic control system for the rolling implements was carried out when sowing dragee seeds of table beet of the Bordeaux variety with a seeding unit consisting of a Belarus-4235 tractor and a Monopil S15/12 precision seeding machine. The system for automatic control of soil density includes the main hardware and software: actuators for maintaining and deepening the rolling working units, microcontrollers, motor drivers, a non-contact ultrasonic sensor, a power supply unit and a sensor for measuring soil density. The paper presents the results of a study to determine the soil density when sowing seeds of table beet, depending on the moisture content of the soil in the sowing layer. The authors describe research methodology, provide graphical relationships between changes in soil density and the depth of seeding, and comment on the main obtained statistical characteristics of the experiment. As a result of the study, structural, echnological and functional diagrams of a rolling rink with an automatic control system using electronically controlled electric cylinders (linear actuators) have been developed. The optimal parameters of the linear drive of the press roller have been established: power - 50W, power supply - 12V, rod stroke - 200…600 mm, speed - 10…45 mm/s, load - 200…900 N. Experimental studies have shown the applicability of the presented system of the automatic control of soil density, which ensures the optimum density of the seedbed of 1.3…1.4 g/cm³. The described technique can be used to develop a soil density control system when sowing seeds of other vegetable crops.

COMPARATIVE TECHNICAL AND ECONOMIC ESTIMATION OF THE SMALL-SCALE ON-FARM COMPOUND FEED PLANTS

On-farm compound feed production from self-produced raw materials is favorable to agricultural enterprises under present-day conditions. The authors carried out a comparative technical and economic study of the conventional and modular small-scale on-farm compound feed plants with a capacity of 2 tons per hour, designed for agricultural enterprises with an average livestock population of 6…8 thousand pigs. The proposed modular plant consists of two modules – the operative storage of raw materials and the main module of grinding and mixing. Modules with installed equipment are delivered and placed on a light foundation, connected by transport equipment and with tanks for raw materials and fi nished products. The conventional factory is a technological line housed in a hangar and used for crushing, metering, and mixing raw materials. It consists of a separator, a hammer mill, weighing equipment, a mixer, containers for raw materials and fi nished products, transport, and aspiration equipment. The technical and economic analysis has shown that the erection and operation of the on-farm modular enterprise require 41% less capital investments than a traditional compound feed plant of the same capacity. The use of a small-scale modular plant will reduce operating costs by 23.8% (from 3094 to 2358 thousand rubles), increase the specifi c economic eff ect from the compound feed production by 1.6% (from 8.64 to 8.78 thousand rubles per ton) and return on margin by 4% (from 10.2 to 10.6%), reduce the payback period by 42% (from 0.8 to 0.46 years), and increase the net present value by 3% (from 66167 to 68216 thousand rubles), as compared to a conventional enterprise. The modular on-farm plants producing loose compound feed with a productivity of up to 3 tons per hour are profi table and economically sound as they can increase production effi ciency of compound feeds for farm animals.`

IMPROVING DEGRADED AGRICULTURAL MOUNTAIN LANDSCAPES BY THE SLITTING METHOD

The article examines a laboratory sample of a maneuverable unit for slitting mountain meadows and pastures. Its design is adapted for work in a mountainous agricultural landscape with degraded soils having a slope of cultivated areas up to 15°. The study object is the structural, technological, operational, and agrotechnical parameters of the laboratory sample and the graphic-analytical rationalization of the working process of slitting on the slope. The technical tests of the laboratory model were carried out in Dargavs, RNO-Alania, at an altitude of 1540 meters above sea level with a slope steepness of up to 15°. The authors determined the indicators of test conditions and functional operation in accordance with GOST 33687-2016. The laboratory sample of a slitter (paraplow) mounted on the “Fenshaw-180” mini-tractor was adapted to a mountain zone with a reverse (obtuse) angle of penetration into the soil. The authors off er an optimal scheme for the arrangement of the working tools of the slitter. They determined the technology of its traveling along the slope and the design of the working tools providing the distance between the slits of 1000 ± 5 mm, the slitting depth of 200…220 mm, the slit width of 10…30 mm ± 5 mm. The considered sample of the unit for slitting mountain meadows and pastures will improve the moisture and air supply of the lower soil layers; reduce the degradation processes of slope areas, increase labor productivity, environmental sustainability, and grassland farming effi ciency.

RESEARCH RESULTS OF THE MODIFIED WORKING TOOL OF THE COMBINED ROTARY MOWER

Currently, there are practically no mechanization tools on the market that combine grass removal (mowing) and the levelling loosening of the upper soil layer, while cutting the root systems contained in the soil in one pass. The purpose of the study was to provide a theoretical rationale of the modifi ed design of the working tool of the combined rotary mower, as well as to conduct its laboratory and fi eld studies. Complex theoretical, laboratory and fi eld studies were carried out using the equipment of the Department of Technological and Transport Machines and Complexes, the Department of Technology of Processing and Storage of Agricultural Products of Tver State Agricultural Academy and recognized methods of experimental research. In the course of theoretical studies, the main parameters of the new working tool were determined, which enabled two technological processes to be carried out in one pass: grass mowing and cutting with loosening of the top soil layer (0…10 cm). On the basis of the obtained data, a workable model of the working tool was designed. When tested in laboratory conditions, regardless of the operating modes and the initial state of the cultivated soil, improved agrophysical properties were observed in terms of absolute humidity and saturation with root residues. It was found that the most optimal level of absolute humidity for the impact of the working tool on soils of light-loamy granulometric composition was 20%, while the best structural and density indicators were observed at all values of soil saturation with root residues; thgey averaged 2.24 units and 1.26 g/cm3. It has been established that at low operating speeds, it is advisable to use a higher rotation speed of the working tool (at 150 rpm), at the same time, with an increase in speed, the speed of rotation should be reduced (to 110 rpm). As a result of fi eld experiments, convincing data were obtained on the feasibility of using a new working tool that provides eff ective mowing of grassland vegetation (the purity of the stem cut is 95.6%) and loosening of the surface layer of the soil (0…10 cm), increasing the structural coeffi cient by 26.8% while optimizing the density and grinding of root systems. The next stages of the study include developing and manufacturing a workable design of a combined rotary mower prototype that ensures the optimal energy intensity of performance and the required quality of technological processes.

TECHNOLOGIES AND MACHINES FOR MAKING PHYSICAL IMPACT ON SOIL, SEEDS, AND PLANTS

Getting a high-quality yield depends on a signifi cant number of factors: soil and climatic conditions, the quality of seed or planting material, cultivation technologies, the level of technical equipment, etc. In addition, the effi ciency of agricultural production depends primarily on the use of chemicals to treat various biological objects (soil, seeds, and plants). In turn, they contribute to the “pollution” of chemical compounds and their components used in the treatment of soil, soil waters, rivers, and reservoirs, as well as crops grown. To prevent the negative eff ect of chemicals on biological objects, it is necessary to use alternative treatment methods, which can include a physical infl uence, carried out by various types of radiation, gaseous media, etc. The authors outline tasks to be solved in the machine design. They include ensuring physical infl uence on biological material, using basic design principles to solve the problems of forming a system of agricultural machines and technologies to ensure high productivity, environmental safety, and obtaining healthy food by completely or partially replacing chemical infl uence with the physical one. The paper proposes designs of devices to process the soil, seeds, and plants by physical methods aimed at combating weeds, pests, and diseases, as well as stimulating the germination and intensive development of seed and planting material cultivated both in open and protected ground.