When separating (cleaning) lightweight seed mixtures with the help of vibratory machines, there is an issue related to the harmful effect of air movement in the gaps between parallel working surfaces of vibratory machine units. This factor is particularly harmful to seed material, which is sensitive to air movement (some medicinal and vegetable crops). To address this issue, the design of vibratory machines is changed while their operational regimes are configured accordingly. This requires many full-scale experiments and (or) time-consuming personal computer-based simulation of the working processes of the vibrational motion of such seed mixtures. This paper proposes several regression models that make it possible to replace time-consuming numerical modeling with simple analytical expressions (regression equations). These equations are used for a quantitative assessment of the degree of influence of aerodynamics on the kinematic parameters of the vibrational motion of particles of seed mixtures. The assessment is derived depending on the geometric characteristics of the aerodynamic screen, the design of the unit, and the amplitude of oscillations of the working surfaces of a vibratory machine. The models take the form of equations of multiple linear regression of the second order, obtained on the basis of a series of numerical experiments. The processes of vibration movement of the seed material of parsnips, lettuce, and fragrant dill were investigated. The coefficient of determination equaled 0.956...0.967. The results reported here are useful for the construction of algorithms to optimize the design and adjust the operating modes of vibratory separators according to the criterion of minimizing the harmful effects of the aerodynamic factor

The present paper is aimed at improving minimization methods in traffic flows, particularly reducing the costs of civil transportation through sections of the transport network by giving priority to public transport in densely developed areas. In cities with a radial and radial–circular planning scheme of the road network, where arterial traffic flows converge in the central part, the challenge of street congestion with traffic often arises. As a result, delays of all types of vehicles increase, which causes excessive travel time for users of private and public transport. In this regard, it is proposed to divide the sections of the transport network into eight types based on their geometric parameters and traffic conditions. This differentiation of sections improves the existing methods for determining the spatial delay of traffic flows on sections of the transport network with different parameters. It was achieved by considering the duration of vehicles passing signalized intersections and pedestrian crosswalks and the sections of streets between them, while simultaneously recording the duration of public transport movement, as well as the time they spend at stopping points, using GPS receivers. The results of onsite monitoring and further computations revealed that there are particular urban sections with specific, different distances between adjacent stop lines that are critical for public transport operation. Furthermore, based on the delay criterion, there were three different passage modes proposed to improve the efficiency of the traffic.

In this article the structural features of friction pairs of brakes are analyzed. Heat transfer processes with new boundary conditions are described analytically with the addition of flow conditions and the appearance of a boundary thermal layer to convective heat transfer. The joint action of heat conduction and convection fields is presented. The release of heat during friction is due to the destruction of adhesive bonds in the actual contact zones, and the stress–strain state of micro-roughnesses. It should be said that due to the presence of accompanying transfer processes, complex heat transfer is much more complex compared to purely conductive, convective, and radiative heat transfer, which significantly complicates its analytical and experimental study. In this regard, the processes of complex heat transfer are currently studied little. From the point of view of non-equilibrium thermodynamics, the main task of describing the transfer process is to establish a relationship between the magnitude of the specific flux and the surface-volume temperatures that it causes in the metallic friction elements of the brakes. Additionally, as a result, an assessment of conductive and convective heat transfer in friction pairs of brake devices was made.

Maritime transportation is the essence of the international economy. Today, about ninety percent of world trade is carried out by sea through 50,000 merchant ships. Most of these vessels are powered by mainline diesel engines due to their reliability and fuel efficiency. Reliability of system elements in general depends on random failures, significant wear during operation, additional wear during start-up. Accidental damage to diesel engine components is a major hazard during operation, as some parts (such as cylinder liners and pistons) are usually replaced during repairs. On the other hand, preventive service does not eliminate random malfunctions. Therefore, in the general problem of assessing the reliability of a diesel engine, there is a mathematical problem of assessing the reliability and durability, taking into account only the random failures of its elements, which are of the greatest practical importance. The purpose of the work is a mathematical study of the reliability of parts of the cylinder-piston group of the main engines of dry cargo ships. Using a systematic approach and a probabilistic statistical method, it was established that the most common and difficult case is the simultaneous action on a system element (for example, a cylinder sleeve) of factors that cause wear during the period of operation (including during the start-up period) and accidental failures. It was determined that the quality of the cylinder-piston system in ships of the "Ostriv Rosiyskiy" type is higher than in the ships of the "Simferopol" and "Murom" types. Empirical formulas for estimating the probability of emergency failure of main engine system elements during the period of operation between factory repairs were obtained, where the main danger during the period of operation was carried by accidental failures. Based on the results of the study, it is possible to establish a schedule for the periodicity of maintenance of the ship's main engine and the cost of losses due to ship downtime due to failures, and can also be used in the reliability study of other types of ship's main engines. The results make it possible to determine the reliability of the parts of the cylinder-piston group of the main engines of dry cargo ships. and, in particular, to establish the maintenance schedule of the ship's main engine and the cost of damages due to ship downtime due to failures, and can also be used in the study of the reliability of other types of main engines of other series of ships

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