Articles

ABSTRACT: This article examines one of the most important strokes in tennis sport, namely, service strokes. The study covers three types of strokes: flat, slice, and kick service strokes. A specially made program has been compiled in the area of MatLab, with the help of which the strongly nonlinear differential equations are integrated. These equations […]

ABSTRACT: The article considers the impact interaction of a railway vehicle with a fixed barrier. The movement of the vehicle is carried out at different velocities. A dynamic model of a buffer is offered, which includes an elastic element, a damper, and a friction mechanism. The elastic element has a nonlinear characteristic. The damper is

ABSTRACT: Bipolar Plates (BPPs) are the most crucial component of the Polymer Electrolyte Membrane (PEM) fuel cell system. To improve fuel cell stack performance and lifetime, corrosion resistance and Interfacial Contact Resistance (ICR) enhancement are two essential factors for metallic BPPs. One of the most effective methods to achieve this purpose is adding a thin

ABSTRACT: Modern tennis sport is characterized by constant change in several directions. The most significant of these changes are connected to the design of tennis rackets. The composite material of the rocket’s frame is continuously improved. It is also working hard on improving the tennis strings. Tennis balls are also being modified. All these innovations

ABSTRACT: The oscillations of a pendulum suspended on an elastic beam are examined. The mathematical pendulum is a material point suspended on an ideal rigid and massless rod. The upper end of the rod is connected by a joint with an elastic beam on two supports. The beam is considered to be perfectly elastic and

ABSTRACT: Modern tennis players use a variety of strokes. From the physical point of view, these shots can be classified into eight main groups depending on the way the racket interacts with the tennis ball. These are strokes with top, bottom, side, top-side, and bottom-side rotation, as well as strokes without rotation. These eight interactions

ABSTRACT: The article examines the three-dimensional vibrations of an elliptical disk. It is rigidly connected to a horizontal cylindrical shaft. The normal axis to the plane of the disk makes an acute angle with the axis of the shaft. The shaft is considered to be a cylindrical perfectly elastic and weightless rod with stiffness of

ABSTRACT: The purpose of the study is to examine the adaptation of coal mining enterprises to the requirements of the Climate Agenda and the prospects for a low-carbon future in the Kuzbass region. The subject of the research is the impact of coal mining on the conservation of the region’s biocapacity and the future “green”

ABSTRACT: The purpose of the study is to examine the issues of assessing the anthropogenic impact on the ecosystem and sustainable development of a region using the example of Kuzbass. The subject of the study is to substantiate the need to improve the measurements of sustainable development of the regional economy from the point of

ABSTRACT: Small vibrations of a cylindrical shaft caused by inertial excitations are studied in this paper. The shaft is vertically situated. It consists of two sections with different cross sections. It is supported by a spherical and a cylindrical joint. The two supporting devices have horizontal elasticity. Between the two supports, and also at the

ABSTRACT: In this article, new equations called Condensed Lagrange equations (CLEs) are defined. With their help, the rigid body’s absolute general motion is studied. The rigid body is considered to be homogeneous and unsymmetrical. CLEs are similar in structure to the classical Lagrange equations from the second type, applied in vector-matrix form, but CLEs are

ABSTRACT: In this article, a rigid body’s absolute general motion is studied. The rigid body is assumed as homogeneous and unsymmetrical. New additional kinetic characteristics are used. The most important of these are the following: the vector-real generalized velocity of the rigid body, the vector generalized impulse of the rigid body, and the vector-real generalized

ABSTRACT: The absolute motion of an arbitrary asymmetric rigid body is studied. This motion is determined after its relative motion has been obtained. The most important peculiarity in this dynamical rigid body model is that the selected pole does not coincide with its mass center. Seven new kinematic characteristics have been defined. The first ones

ABSTRACT: The relative motion of an arbitrary asymmetrical rigid body in this article is studied. Three new additional kinematic characteristics are defined, namely, vectors-real absolute, transmissive, and relative generalized velocity. A new theorem for summation of the rigid body’s real generalized velocities, with these new additional kinematic characteristics, is formulated. Using the final differential equations

ABSTRACT: In this paper, the trajectories of a soccer ball for the most important kicks in the football game – a corner kick and a direct free kick are studied. The soccer ball is modeled as an ideal rigid hollow spherical body with six degrees of freedom, which performs a general motion in an immovable