Vol 30, No 4 (2020)

Introduction. For cultivated crops, the optimal form of spacing is square form, which is provided by the square cluster method of planting. Currently, due to the high metal consumption and low productivity, this method of planting has been replaced with a single-seed planting one. But this does not solve the problem of rational distribution of seeds in the field, so the problem of plant spacing with the use of the optimal square form of spacing is relevant. 
Materials and Methods. A programmable square cluster planting using local coordination of the seeding apparatus and an algorithm for its realization are considered. The article describes the construction of a simulation model of sowing planting in Simulink Matlab with justification of its elements. 
Results. The graphs of the distance traveled, positions coordinates of the flap opening and control signals depending on the time are constructed. The analysis of the encoder settings is carried out. When varied the plant spacing and the coordinates of the first flap opening, the dimension of the last seed cluster changes in the range from –2.6 ∙ 10–3 to 2.7 ∙ 10–3 m. 
Discussion and Conclusion. The analysis of the simulation model of the square cluster planting showed that the algorithm for controlling executive mechanisms together with the local coordination system works adequately and provides high precision of placing seed clusters in the field. The dependences of the optimal number of pulses per an encoder shaft revolution on the specified seed spacing and radius of the track measuring wheel are determined. It was determined that the maximum dimension of the last seed cluster does not exceed 2.7 mm per 1 000 m (for x = 0.3 m and t = 0.7 m).

Introduction. Currently, in various technology areas, bronze, cast iron and other antifriction metals are replaced by polymer composites, which extend significantly service life of tribocoupling. The study deals with determining the optimal specific energy consumption for the mechanical activation of the polymer dry mixed powders and nanomodifiers in the planetary ball mill Pulverisette 7, which ensure the best complex of physico-mechanical and rheological properties of nanocomposites.
Materials and Methods. In this work, we used GUR 4120 Ticona ultra-high-molecularweight polyethylene with a molecular weight of 5 million, a Tuball Matrix Beta concentrate of activated carbon nanotubes at a concentration of 0.1%, calculated with reference to carbon nanotubes, and hydrophobic nanocrystalline silicon dioxide with a dispersion of 20 nm at the same concentration. Mechanical co-activation of polymer powders and nanomodifiers, when varying the specific energy consumption, was carried out in the planetary ball mill Pulverisette 7. The production of films from powders, for studying the elasticstrength and rheological characteristics of nanocomposites, was carried out with the use of the hydraulic press Gibitre. Tests were carried out respectively on the tensile testing machine UAI-7000 M and the rheometer Haake MARS III.
Results. It has been established that the best physico-mechanical and rheological properties of nanocomposites are with specific energy consumption for mechanical activation of 3,000‒3,200 J/g that allows us to consider them optimal. The mechanical activation of ultra-high molecular weight polyethylene powder, reducing slightly the elasticity modulus and tensile strength of thermally pressed samples, does not affect the dynamic viscosity of melts at an energy consumption of 650‒4,550 J/g.
Discussion and Conclusion. The use of carbon nanotubes and nanocrystalline silicon dioxide at a concentration of 0.1% can significantly improve the physical-mechanical and rheological properties of the polymer with energy costs of 3,000‒3,200 J/g for mechanical activation in planetary ball mills. 

Introduction. Improving the efficiency of agricultural operations and off-road logistics require new highly efficient non-road machinery with low pressure on road surface. The versatility of the use of this machinery imposes additional requirements on its design, including those related to road traffic safety on public roads. Changes in brake design are required to ensure safe braking performance when larger diameter wheels are used for the reason that to produce standard braking force according to the technical regulations for the safety of wheeled vehicles, requires more braking torque when using larger diameter wheels.
Materials and Methods. The article proposes a model for calculating the braking parameters of transport and technological agricultural machines equipped with ultra-low pressure wheels. The model differs from those used earlier in that its output parameter is not the braking efficiency, but the time difference between the front and rear axle locks.
Results. Fulfilling the condition of the front axle advance locking ensures the stability of the tractor motion during emergency braking that has a positive effect on road traffic safety. The results of the study suggest that to ensure the safe motion of the machines equipped with ultra-low pressure tires on public roads, it is necessary that the ratio of the distance from the center of mass to the front axle is at least not less than the distance from the center of mass to the road surface.
Discussion and Conclusion. The obtained mathematical dependencies allow us to justify different technical solutions for ensuring safe road movement of transport and technological agricultural machines equipped with ultra-low pressure tires. Thus, the maximum permissible height of the center of mass can be assumed to be equal to 90% of the distance from the location of the center of mass of an agricultural transport and technological machine to its front (controlled) axis.

Introduction. In agricultural production during transportation of goods it is accepted to allocate transport and transport-technological processes with the corresponding methods of rationing works. The peculiarity of the processes is the sequential execution of cyclic operations, providing transportation of technological material to the destination directly or with preliminary collection (subsequent distribution) on the field. 
Materials and Methods. The performance standards were identified by the extrapolation, interpolation or approximation methods based on their estimated performance. The classical method of differentiating functions was used to find the extrema.
Results. At length of fertilizer transportation by direct-flow technology LГ = 9 km and application dose U = 0.06 kg/m2, the following values of transport and technological facilities performance have been obtained: a) for vehicles to deliver fertilizers to fertilizer storehouses by Ural-432065 truck (body) W = 9.1 t/h, W = 6.3 t/h for tractor with MTZ-82 trailer. 1+2PTS-6; b) for transport and technological facilities to transport and distribute fertilizers by Ural-432065 (Amazone spreader) W = 5.5 t/h, W = 3.9 t/h for tractor with MTZ-82.1+RUM-6 trailer.
Discussion and Conclusion. Based on the analysis of methods, the authors have made the case for the unification of calculating the standardized volumes of works, choice of composition, and comparison of the effectiveness of using vehicles, if they are used as transport and transport-technological facilities. A mathematical model and algorithm fora uniform calculation of the performance of different transport and technological facilities are presented. The way to determine the approximate rate of generation of funds that do not have standard indicators of work. The explanation of the innovations is accompanied by a formula device, which is based on the conclusion of the dependencies of out- and incycle components of the shift time balance on the engine power of the mobile device. 

Introduction. Rational recycling of agricultural machinery, which has reached the end of its service life, is an urgent problem of the modern agro-industrial complex. In this regard, using the physical model for recycling agricultural machinery, reached its service life, is a solution to the problem of resource recycling.
Materials and Methods. The paired linear regression analysis method was used to conduct statistical research of experimental data and develop a regression model. The authors calculated the recyclability rate values for the entire agricultural machinery nomenclature and its average value through using regression equation.
Results. Based on the analysis of indicators for technical condition of being recycled products, it was established that for developing a conceptual model of agricultural machinery recycling, it is preferable to use four main groups of indicators: technical condition, material capacity, manufacturability, and safety of components. The proposed group of indicators determines the possibility of recycling the machinery units. The results of researching the influence of indicators of design complexity, technical performance, condition, nomenclature and quantitative composition of agricultural machinery on the recyclability are presented.

Discussion and Conclusion. According to the research results, a conceptual physical model for recyclability of agricultural machinery was developed that allows planning more effectively measures for recycling various types of agricultural machinery when conducting a comparative analysis of the entire nomenclature composition. The adopted restrictions allow estimating the technical condition and recyclability of agricultural machinery using the conceptual physical model of recyclability. The relationships between the storage time, complexity of technical performance, material capacity, quantitative composition (volume of recycling) and recyclability rate of agricultural machinery are revealed.

Introduction. The earth cutter resource depends on the characteristics of the materials they are made from. In particular, the important parameters that directly affect the tillage tool parts efficiency and durability are the values and ratios of the coefficients of relative wear resistance of the two-layer parts materials. It is established that the characteristics of the relative wear resistance of the materials for earth cutter parts vary depending on the treated soil properties. The objectives of the study are to consider the influence of soil conditions on the values of the relative wear resistance coefficients of two-layer earth cutter part materials and to carry out a comparative assessment of their resource and use efficiency.
Materials and Methods. The authors gave a generalized dependence of the wear proportionality to the existing specific pressures values. The characteristics of soil abrasion were given. The scientific substantiation of the changes in the characteristics of the materials wear resistance at various values of specific pressures was given.
Results. The results of the operational resource tests and the studies of two-layer and monometallic earth cutters are presented. The influences of the values of the operating specific pressures on the coefficients of the relative wear resistance of the materials for the tillage machine parts are determined.
Discussion and Conclusion. The authors have found out that the coefficients of relative wear resistance of materials are not constant, but vary depending on the current surface specific pressures. The correlation of the specific pressure values with the parameters of the tillage operation, in particular with the furrow slice hardness was established. It has been found that while increasing the cultivated soil hardness, the coefficients of various materials relative wear resistance get closer to each other. The difference varies from 1.80 to1.85 times.