On the shock wave front speed under high-voltage electric discharge in water

© 2017, Pleiades Publishing, Ltd.The pressure wave propagation under high-voltage electric discharge in water was investigated experimentally. The shock wave front speed was determined for the considered range of parameters

Modernization of clamping unit of draft of endosurgical monopolar forceps

© Published under licence by IOP Publishing Ltd. The object of research is the plasma-electrolytic processing, namely the influence of area ratio of the anode and the cathode to the parameters of the process. Defined area ratio anode to cathode, at which the discharge burning occurs on the cathode, on the anode or on the both electrodes simultaneously. Determine the required ratio of the electrodes (S1 ≥ 2 S2) for discharge burning of the electrode S2

The effects of superconductor-stabilizer interfacial resistance on quench of current-carrying coated conductor

We present the results of numerical analysis of a model of normal zone propagation in coated conductors. The main emphasis is on the effects of increased contact resistance between the superconducting film and the stabilizer on the speed of normal zone propagation, the maximum temperature rise inside the normal zone, and the stability margins. We show that with increasing contact resistance the speed of normal zone propagation increases, the maximum temperature inside the normal zone decreases, and stability margins shrink. This may have an overall beneficial effect on quench protection quality of coated conductors. We also briefly discuss the propagation of solitons and development of the temperature modulation along the wire.Comment: To be published in Superconductor Science and Technology. This preprint contains one animated figure (Fig. 6(a)). when asked whether you want to play the content, click "Play". Acrobat Reader (Windows and Mac, but not Linux) will play embedded flash movies. In the printed copy Fig. 6(b) will show the temperature profile at gamma t=15

The vertex coordinates of the Galaxy's stellar systems according to the Gaia DR3 catalogue

We present the results of determining the coordinates of the vertices of various stellar systems, the centroids of which are located in the Galactic plane. To do this, the positions, parallaxes, proper motions, and radial velocities of red giants and subgiants contained in the $Gaia$~DR3 catalogue have been used. When determining the components of the deformation velocity tensors in local coordinate systems, we found the coordinates of the vertices of the stellar systems under study. It turned out that there is a complex dependence of vertex deviations $l_{xy}$ in Galactocentric cylindrical ($R, \theta$) and Galactic rectangular ($X,Y$) coordinates. Based on the approach proposed in this paper, heliocentric distances to vertices have been determined for the first time. The results obtained show that in addition to the fact that the angular coordinates of the Galactic center and the vertices of stellar systems do not coincide, their heliocentric distances do not coincide as well. This presumably indicates that there are structures in the Galaxy that noticeably affect its axisymmetry.Comment: 10 pages, 14 figures, 1 table

Analytical Solution for the Current Distribution in Multistrand Superconducting Cables

Current distribution in multistrand superconducting cables can be a major concern for stability in superconducting magnets and for field quality in particle accelerator magnets. In this paper we describe multistrand superconducting cables by means of a distributed parameters circuit model. We derive a system of partial differential equations governing current distribution in the cable and we give the analytical solution of the general system. We then specialize the general solution to the particular case of uniform cable properties. In the particular case of a two-strand cable, we show that the analytical solution presented here is identical to the one already available in the literature. For a cable made of N equal strands we give a closed form solution that to our knowledge was never presented before. We finally validate the analytical solution by comparison to numerical results in the case of a step-like spatial distribution of the magnetic field over a short Rutherford cable, both in transient and steady state conditions

Frontiers, challenges, and solutions in modeling of swift heavy ion effects in materials

Since a few breakthroughs in the fundamental understanding of the effects of swift heavy ions (SHI) decelerating in the electronic stopping regime in the matter have been achieved in the last decade, it motivated us to review the state-of-the-art approaches in the modeling of SHI effects. The SHI track kinetics occurs via several well-separated stages: from attoseconds in ion-impact ionization depositing energy in a target, to femtoseconds of electron transport and hole cascades, to picoseconds of lattice excitation and response, to nanoseconds of atomic relaxation, and even longer macroscopic reaction. Each stage requires its own approaches for quantitative description. We discuss that understanding the links between the stages makes it possible to describe the entire track kinetics within a multiscale model without fitting procedures. The review focuses on the underlying physical mechanisms of each process, the dominant effects they produce, and the limitations of the existing approaches as well as various numerical techniques implementing these models. It provides an overview of ab-initio-based modeling of the evolution of the electronic properties; Monte Carlo simulations of nonequilibrium electronic transport; molecular dynamics modeling of atomic reaction on the surface and in the bulk; kinetic Mote Carlo of atomic defect kinetics; finite-difference methods of tracks interaction with chemical solvents describing etching kinetics. We outline the modern methods that couple these approaches into multiscale multidisciplinary models and point to their bottlenecks, strengths, and weaknesses. The analysis is accompanied by examples of important results improving the understanding of track formation in various materials. Summarizing the most recent advances in the field of the track formation process, the review delivers a comprehensive picture and detailed understanding of the phenomena.Comment: to be submitte

Analysis on compressor blading conditions of helicopter’s gas-Turbine engine working in polluted environment

© Research India Publications.Working in the dusty air pollution the air-gas channel of the engine is polluted. This results in deterioration of engine power plants. In this paper we present the results of studies of mass, density, thickness and microstructure of deposits on the rotor blades of a helicopter gas-turbine engine compressor having a nominal capacity of 883 kW after working 1500 h. The researches were conducted on ten blades of each stage. The blades were weighed before and after treatment, and then the averaged sludge mass was calculated. The results show that at the latter stages of the compressor deposit density was greater than at the first ones. Mode with full manifestation of roughness for a given engine is implemented in the first six stages of the compressor. It is concluded that the characteristics of the boundary layer and the value of the coefficient of friction on the surface of the blades are mostly influenced by the size of the arithmetic average height of irregularities Rz. The resulting data is used to develop methods of purifying of the compressor flow path