Explore the vast range of titles available.

This paper discusses the issues of creating a ballistic facility for use in laboratory conditions and achieving throwing speeds of up to 2000 m/s for massive objects. The design of the facility was proposed and the results of the analytical calculation of the achieved speeds were presented. The verification of the analytical calculation and the results of experiments on the prototype ballistic facility was done.

This article discusses the application of a mathematical model of heat transfer during welding to create an algorithm for choosing the welding mode parameters during programming of automatic welding systems. The results of the industrial implementation of a robotic welding system equipped with a developed algorithm for choosing a welding mode are presented.

Modern quality management systems for welding products are based on procedures to minimize the likelihood of typical defects. The reasons for deviations of the energy parameters of the welding process include disturbances along the length of the arc or its breaks associated with a spasmodic change in the electrode wire feed speed, violation of the power circuit with the welded product, mains voltage, and shielding gas consumption. To establish a connection between deviations of the welding parameters with the quality indicators of the welded joints, a model for the formation of a weld seam under the conditions of technological disturbances has been developed. It is shown that the formation of the crater depends not only on the duration of the arc break, but also on the welding parameters. It has been established that in the presence of lateral oscillation of the electrode, an arc break significantly increases the undercut, the maximum depth of which movesto the center of the groove to the cutting center as the break duration increases. Whereas an increase in the amplitude of lateral oscillation of the electrode causes a significant increase in the depth of the crater.

The increase of the welding productivity is still of immediate interest, which in turn requires the development and implementation of more high-performance welding methods that ensure a consistently high quality of welded joints. One of the ways to further increase the productivity of arc welding processes in the construction of tanks is the industrial use of automatic double-sided arc welding with multiple electrodes in separate weld pools. To establish the relationship between the parameters of the welding mode, energy characteristics, as well as the distance between the torches and their angle of inclination relative to the groove, a physical and mathematical model of the production of the welding joint when four arcs participate in pairs from both sides of the joint has been developed. Thus, computer modeling showed that during weld formation with the movement of the electrode down (vertical down), the possibility of supplying each pair of arcs with pulsed current should be taken into account. During groove filling with the movement of the electrodes up (vertical up), their lateral oscillations and delays at the edges should be carried out according to an aperiodic law in order to minimize the effects of 'magnetic blow'.

The results of Global Navigational Satellite System (GNSS) observations in the regions of large earthquakes are analyzed. The characteristics of the Earth’s surface deformations before, during, and after the earthquakes are considered. The obtained results demonstrate the presence of anomalous deformations close to the epicenters of the events. Statistical estimates of the anomalous strains and their relationship with measurement errors are obtained. Conclusions are drawn about the probable use of local GNSS networks to assess the risk of the occurrence of strong seismic events.

Abstract—This paper reports the results of numerical modeling of the stress–strain state of the epicentral area before and after the August 24, 2014 earthquake in Napa, California, USA, compared to calculated data obtained in instrumental studies in the dilatation areas based on GPS observation results. Numerical modeling has made it possible to calculate the stress–strain state of the epicentral area affected by the tectonic fault system. GPS observation data on the epicentral area of the earthquake and the results of numerical modeling of the stress–strain state before and after the considered earthquake have been analyzed. A trend toward localization of earthquake epicenters in the region of high stress intensity concentration has been confirmed. It has been proved that aftershock development is due to the drop in stress caused by a new fracture and that the aftershock cluster that occurred was localized in the area of decreased stress intensity.

The normal interaction of ice particles with a composite orthotropic organoplastic plate is modeled scientifically. The range of interaction velocities from 80 to 500 m/s is considered. To develop a mathematical model and numerical algorithm, a coordinated series of physical and numerical experiments have been conducted on impact loading of the composite plate with steel spheres. The behavior and fracture of the composite and ice are described by the elastic-brittle model taking into account their different strengths in compression and tension. Numerical simulation is carried out by the finite element method using the software complex EFES developed by the authors. The composite plate fracture under simultaneous impact by a group of particles and sequential impact by a particle stream is investigated.

The use of potential (integral) representations is studied when computing Green's functions for boundary value problems stated for Laplace and biharmonic equations over regions of complex configuration in two dimensions. The emphasis is on the non-traditional potentials, whose observation and source points occupy different sets. Such potentials reduce the original boundary value problems to functional (integral) equations with smooth kernels. Special integral representations are studied, the ones whose kernels are built not of the fundamental solutions of governing differential equations but of the Green's functions for simply shaped regions, which are associated with boundary value problems under consideration. Such integral representations are called here the modified potentials, to the contrary of the standard potentials that are referred to as the classical potentials. Computability of different existing forms of Green's functions is discussed. Computational experiments have been conducted to analyze the relative effectiveness of both types of potentials when solving test problems.

Objectives. To assess the efficacy of Reslip (doxylamine) in acute insomnia in comparison with Donormyl. Materials and methods. A multicenter, open, randomized trial was conducted at six medical centers in the Russian Federation. The trial included 60 patients with acute insomnia aged 30–59 years, who were randomized into two groups. Patients of one group received Reslip and those of the other received Donormyl at the same dose and regime. Results. Most patients in both groups experienced improvements in the clinical signs of acute insomnia. The severity of insomnia, daytime drowsiness, and reductions in quality of sleep in both groups showed highly significant decreases. Side effects from the drugs were rare and in most cases did not require treatment termination. There were no significant differences in treatment results with Reslip and Donormyl. Conclusions. Short-term treatment with doxylamine formulations had marked positive clinical effects in acute insomnia, combined with satisfactory tolerance by the patients. The Russian doxylamine formulation Reslip had clinical efficacy and tolerance which were no different from those of Donormyl and can be used in clinical practice for the treatment of acute insomnia.

The production of tinplate (thickness <0.18 mm) by single-pass rolling is introduced. Measures for improving its surface quality and mechanical properties are developed.