This article is devoted to new approaches to modeling pneumatic processes occurring in the brake system of a train. Various methods are used to model pneumatic processes in various elements of the brake system. Thus, the Navier–Stokes equation is commonly used to model changes in the pressure in the brake line. At the same time, the models of non-stationary processes occurring in the brake line do not take into account the influence of processes in the main reservoir. Indicator diagrams or thermodynamic equations are usually used to model the operation of the air distributor. This approach has insufficient accuracy when compared with experimental studies. To date, the mathematical models used to calculate pneumatic systems have an error of 12–15
Authors research the task of aluminum plate geometric parameters at excision of surface layer material on both sides of considering billet. This allows us to use the hypothesis of the identity of the areas of the regions of considering stresses. The authors propose a nonstandard approach to residual stresses identification for different variants of removing the surface layer with researching billet into account transformations in the residual stress diagram. They take into account the transformation of the residual stress diagram type at changing the thickness of the aluminum billet. The known theoretical provisions on the type of residual stress diagram and the standard integral mathematical apparatus are the basis of the proposed approach. This allows us to build a mathematical model of changing the type of residual stress diagram depending on the thickness of the surface layer removal of the research aluminum plate. The authors research the change in the geometry of the studied workpiece taking into account the correction of the parameters of the residual stress diagram. This makes it possible to use the hypothesis of the equality of the areas of compressive and tensile residual stresses. The obtained results clarify the known theoretical provisions on changing the residual stress diagram after mechanical processing of the studied workpieces made of aluminum alloys.
The issues of measuring the parameters of angular movements of a cargo rope of load-lifting machines with a suspended load for building a system for automatic control of cargo movement are considered on the example of cargo movement by a bridge crane along one horizontal axis. Two components are distinguished in the angular movement of the cargo rope. The first refers to the free pendulum oscillations of the load caused by transients. It is necessary for the control system to generate control actions aimed at quenching these oscillations. The second component is determined by the external force acting on the load, for example, the wind. With a constant external force and no oscillatory movements, this leads to an aperiodic deviation of the cargo rope from the vertical. The need for information about this component is determined by the need to compensate for the movement of the cargo when it is positioned relative to the target delivery point, as well as safety issues. As information sources it is suggested to use micromechanical combined sensor, including accelerometers and sensors of angular speed, located on the cargo rope near the point of fixation of the latter on the crane lifting mechanism. Information on the linear acceleration of the crane trolley is also used. It is proposed to use as such information an estimate of the specified variable built on the basis of an aperiodic link. It is proposed to use a complementary filter or the Kalman filter to estimate the specified components of the angular motion of the cargo rope, as well as its angular velocity. A distinctive property of such a solution from the widely used extended Kalman filter method is the global convergence of estimates. This adds practical value to the proposed approach. Examples of computer simulations are also given.
This article examines the contributions of Doctor of Historical Sciences and Professor Sergey Ilyich Kuznetsov to historical scholarship, education, and the development of international relations at Irkutsk State University. The authors highlight key stages in Kuznetsov's development as an orientalist, drawing the reader's attention to his most important publications. The article outlines the main areas of Kuznetsov's research and his results, recognized in the Russian and international academic community. It also describes Sergey Ilyich's contribution to the development of the Irkutsk State University History Department as a lecturer, administrator (dean and department head), and chairman of the dissertation council for historical sciences.
