The article discusses the prospects for the use of biofuels as an alternative fuel for marine diesel engines. The results of the analysis of applied technologies for the production of biodiesel are presented. The expediency of using a hydrodynamic mixer as a device that ensures the intensity of the transesterification reaction in the production of biodiesel is substantiated. A technological scheme of a laboratory plant for the production of biodiesel has been developed. The results of laboratory studies to determine the optimal material balance of the transesterification reaction for the production of biodiesel in a plant equipped with a hydrodynamic mixer are presented. The main indicators of the interesterification reaction (viscosity, flash point, sediment height) for a plant equipped with a hydrodynamic mixer have been determined. The optimal mass ratio of the transesterification reaction has been established, which ensures the best quality indicators of the resulting biodiesel and allows evaluating the efficiency of the hydrodynamic mixer used in the plant. Recommendations are given on the ratio of vegetable oil and methanol in the production of biodiesel. The best oil/methanol ratio, in terms of biodiesel yield and quality, is 7.5:1. The use of traditional petroleum fuels mixed with biodiesel can be seen as an effective way to reduce air pollution from ships and ensure compliance with the rules of the International Maritime Organization

Nowadays the trend of development of combined units and devices for implementation of specified technological processes is widely spread. The use of combined working organs for graded subsurface tillage allows to reduce the energy and labor costs and to improve the technological process. Based on the comparison methods and monographic survey of existing designs of working organs, their shortcomings when using in arid conditions are revealed. It has been established that in such conditions it is advisable to apply graded subsurface tillage. The analysis of designs of working organs for graded tillage is performed, it allows to establish the advantage of curved elements for surface tillage. A number of shortcomings of subsurface cultivating working organs that have been revealed during years of researches allows for the conclusion about the prospects of replacing blades on curvilinear rippers for surface tillage. The data of content of valuable soil aggregates as a percentage of absolute dry chernozemic soil are given. Based on the analysis of the data, it is established that layer structure can be improved through the use of an element for surface tillage to the depth down to 16 cm in design of chisel working organ. The expediency of mounting of elements for deep and surface tillage on the same tine for graded subsurface tillage is proved. The scheme of a combined working organ is proposed: a chisel for deep tillage and a curvilinear ripper for surface tillage are mounted on its tine, which provides the required crumbling of layer.

The final verification of the performed calculations on the adequacy of the stated hypothesis on the phenomenon being studied is the experiment. Using the method of monographic examination of known bearing systems, the design of an experimental setup for conducting field experimental studies of the working organs of tillage machines was developed. When conducting experimental studies, methods of energy assessment, estimation of technical parameters in accordance with state standards, and methods of full-scale experiment using modern computer diagnostic tools and software are used. The experimental installation for studying the working organs of soil-cultivating machines of the proposed construction includes a frame, support wheels with the possibility of adjusting the depth of soil cultivation by means of a screw mechanism, the attachment mechanism, a hinged mechanism with the fastening of the test organ, the fixing mechanism of the measuring sensor and rigidly fixed to the frame of the apparatus working body to create conditions for the real technological process of functioning. When the system moves through the experimental section, the analog data of the traction resistance read from the measuring sensor is transmitted to the amplifier, from where it is fed through the channel to the analog-to-digital converter board, then the digitized data is fed to the personal computer. It is established that the relative error in the data of the experimental determination of the parameters and indices of the technological process of the working organs of soil-cultivating machines when using the proposed experimental installation with a measuring complex does not exceed 4 % of the results of theoretical studies. The experimental installation allows to carry out investigations in the field conditions with imitation of the real process of operation of the designed tiller machine.

The larger the cross-sectional area of the formation can be processed in a single pass, the less energy is needed to carry out the process. The cross-sectional area of the treated formation is determined by the perimeter of the working body. The circle of all figures of equal perimeter has the largest area. It is advisable to make the working organ ring-shaped. When designing a ring on the plane of the smallest cutting force, an ellipse is formed. From the point of view of physical mathematics, the ellipse is the best curve possessing the minimum property. The optimal shape of the working body is an elliptical ring. The parameter of the ellipse corresponds to the angle of soil displacement in the longitudinal-vertical plane. The elliptical working body carries out the crumbling and separation of the layer with the removal of more solid macroaggregates of soil on the surface and the erosion-hazardous particles that remain inside the formation in the gap between them. Stresses on the working body are determined by interaction with the soil. On the base of the ellipse, the normal stress caused by the backing of the soil layer acts, and the pressure of the cutting edges of the working body affects the cylindrical surfaces. The intensity of stresses arising on the surface of the cylinder is determined on the internal crack of an elliptical shape located in a solid body under the action of a load. The greatest intensity of stresses is localized at the ends of the minor axis of the ellipse, and the smallest at the ends of the major axis. As the cracking angle increases, the stress intensity increases, and then decreases. With an elliptical shape of the working element, the stress intensity zone is wider than that of the circular cutting edge, while deformation of stretching and bending is created in the zone of lateral rounding, which is absent in the plane, and the traction resistance is reduced by 0,5 ... 1,3 kN. The degree of crumbling of elliptical working organs is 87,1 ... 98,5 % of fractions up to 50 mm, combing 1 ... 2 cm, reduction of erosion-hazardous particles 15...22 %.