Fundamental role of local curvature of crystal structure in plastic deformation and fracture of solids

It is shown that strain-induced defects of all kinds are nucleated in local curvature zones of the interfaces between 3D-crystals and 2D-planar subsystem similar to a laser pumping mechanism. Mobile curvature solitons are generalized wave structural carriers of plastic flow. Fracture is the structural phase decay of a crystal in the zones of very high curvature

Search for glitches of gamma-ray pulsars with deep learning

The pulsar glitches are generally assumed to be an apparent manifestation of the superfluid interior of the neutron stars. Most of them were discovered and extensively studied by continuous monitoring in the radio wavelengths. The Fermi-LAT space telescope has made a revolution uncovering a large population of gamma-ray pulsars. In this paper we suggest to employ these observations for the searches of new glitches. We develop the method capable of detecting step-like frequency change associated with glitches in a sparse gamma-ray data. It is based on the calculations of the weighted H-test statistics and glitch identification by a convolutional neural network. The method demonstrates high accuracy on the Monte Carlo set and will be applied for searches of the pulsar glitches in the real gamma-ray data in the future works.Comment: 4 pages, 5 figure

Dynamic recrystallization of Ti-based materials at crack surfaces at elevated temperatures –hybrid cellular automata simulation

In the study a Hybrid discrete-continuum Cellular Automata approach (HCA) based on coupling classical thermomechanics and logics of CA-switching to simulate new phase generation and grain growth is proposed. On the basis of the HCA the numerical experiments on thermal-activated recrystallization of pure titanium in the vicinity of crack edges were conducted. In doing so the 3D cellular automaton simulates the behavior of the V-notched specimen region that imitates the crack tip vicinity. Numerical experiments are aimed at calculating heat expansion in the material under study through taking into account thermal stresses accumulation and microrotation initiation. The latter gives rise to generation of new defects and increasing the local entropy

Effect of surface modification of 5KHV2S steel on the mechanism and intensity of contact wear

The paper presents the experimental study of the contact wear of 5KHV2S steel after surface modification. It is shown that without hardening of the surface layer, 5KHV2S steel is capable of satisfactory operation when a pulsating contact stress of 970 MPa is applied. The most qualitative type of surface modification is the hardening of the surface layer by nitrocementation carried out before quenching and tempering. The proposed technology of volumetric- surface hardening, including forging in a new forging tool, chemical-thermal treatment, quenching and lowtemperature tempering, provided the possibility of increasing the pulsating contact stress to 1 100 MPa, and the operation period during the first 13 000 loading cycles gives wear of the working surface no more than 0,1 mm