Approximate approach of research and assessment of crack resistance of cylindrical housings

In this work, we propose a procedure that allows us to quickly, without involving finite-element packages at the execution stage, evaluate the state of postulated cracks in cylindrical structural elements with internal anticorrosion cladding under pressure and unsteady temperature loading. The procedure contains three components. The first component of the procedure is based on the analytical solution of the unsteady thermal conductivity problem. The second component of the procedure is also analytical relations specifying circumferential and longitudinal stresses in a two-layer cylinder as a function of internal pressure and temperature distribution along the depth of the wall. In the third stage of the procedure, the coefficients of stress intensity along the crack front are determined by the method of influence functions using the known distribution of stresses. To implement this part of the procedure, the influence functions must first be calculated by the finite element method. In this work the example of calculating the functions of influence for longitudinal semi-elliptical cracks of 1/8 wall thickness depth and with the ratio of the principal half-diameters 0.3 and 0.7 is presented. As an example of the implementation of the procedure, comparative calculations were carried out and the elastic-plastic calculation of a cylindrical shell containing longitudinal cracks was given. Stress intensity coefficients along the part of the front located in the base metal were calculated. The results of analytical calculations were conservative until plastic deformations developed in the cladding. At significant plastic strains, the values of the stress intensity coefficients calculated by the proposed procedure, on the contrary, are significantly inferior. This demonstrates once again the fact that calculations in the framework of linear fracture mechanics are not always conservative in relation to calculations in the elastic-plastic formulation. The paper gives an explanation of the reason for the obtained effect

Hall-like effect induced by spin-orbit interaction

The effect of spin-orbit interaction on electron transport properties of a cross-junction structure is studied. It is shown that it results in spin polarization of left and right outgoing electron waves. Consequently, incoming electron wave of a proper polarization induces voltage drop perpendicularly to the direct current flow between source and drain of the considered four-terminal cross-structure. The resulting Hall-like resistance is estimated to be of the order of 10^-3 - 10^-2 h/e^2 for technologically available structures. The effect becomes more pronounced in the vicinity of resonances where Hall-like resistance changes its sign as function of the Fermi energy.Comment: 4 pages (RevTeX), 4 figures, will appear in Phys. Rev. Let

A mathematical model of the rear-trailed top harvester and an evaluation of its motion stability

Received: October 7th, 2021 ; Accepted: December 10th, 2021 ; Published: December 10th, 2021 ; Correspondence: [email protected] the quality of sugar beet harvesting to a great extent depends on the first operation in the process, which involves cutting and harvesting sugar beet tops. This technological process is performed with the use of either the haulm harvesting modules of beet harvesters or top harvesting machines as separate agricultural implements, which are aggregated with a tractor. At the same time, front-mounted harvesters are as widely used as trailed asymmetric implements, in which case the aggregating tractor moves on the already harvested area of the field. The purpose of this work is to determine the optimal design and kinematic parameters that would improve the stability in the performance of the technological process of harvesting sugar beet tops by means of developing the basic theory of the plane-parallel motion performed by the rear-trailed asymmetric top harvester. As a result of the analytical study, an equivalent scheme has been composed, on the basis of which a new computational mathematical model has been developed for the plane-parallel motion of the asymmetric top harvester in the horizontal plane on the assumption that the connection between the wheeled tractor and the rear-trailed top harvester is made in the form of a cylindrical hinge joint. Using the results of mathematical modelling, the system of linear second-order differential equations that determines the transverse movement of the centre of mass of the aggregating wheeled tractor and the rotation of its longitudinal symmetry axis by a certain angle about the said centre of mass as well as the angle of deviation of the rear-trailed asymmetric top harvester from the longitudinal symmetry axis of the tractor at an arbitrary instant of time has been obtained. The solving of the obtained system of differential equations provides for determining the stability and controllability of the motion performed by the asymmetric machine-tractor unit, when it performs the technological process of harvesting sugar beet tops

Health-saving technologies in the educational process

The main task of implementing health-saving technologies – such organization the educational process at all levels so that bigh-schooling and upbringing wald not bi education harmpl for students healthГлавная задача реализации здоровьесберегающих технологий - такая организация образовательного пространства на всех уровнях, при котором качественное обучение, развитие, воспитание обучающихся не сопровождается нанесением ущерба их здоровь

Bound states in the continuum in open Aharonov-Bohm rings

Using formalism of effective Hamiltonian we consider bound states in continuum (BIC). They are those eigen states of non-hermitian effective Hamiltonian which have real eigen values. It is shown that BICs are orthogonal to open channels of the leads, i.e. disconnected from the continuum. As a result BICs can be superposed to transport solution with arbitrary coefficient and exist in propagation band. The one-dimensional Aharonov-Bohm rings that are opened by attaching single-channel leads to them allow exact consideration of BICs. BICs occur at discrete values of energy and magnetic flux however it's realization strongly depend on a way to the BIC's point.Comment: 5 pgaes, 4 figure

Dynamical spin-electric coupling in a quantum dot

Due to the spin-orbital coupling in a semiconductor quantum dot, a freely precessing electron spin produces a time-dependent charge density. This creates a sizeable electric field outside the dot, leading to promising applications in spintronics. The spin-electric coupling can be employed for non-invasive single spin detection by electrical methods. We also consider a spin relaxation mechanism due to long-range coupling to electrons in gates and elsewhere in the system, and find a contribution comparable to, and in some cases dominant over previously discussed mechanisms.Comment: 4 pages, 2 figure

TECHNOLOGIES AND EQUIPMENT FOR RECYCLING AND INCINERATION OF WASTE, RDF FUEL

В работе рассмотрено различное оборудование Японии, России и Европейских стран для переработки, сжигания и утилизации ТБО и RDF топлива. Проанализировано развитие технологий различного рынка. Выявлены оптимальные показатели оборудования.The paper considers various equipment of Japan, Russia and European countries for processing, combustion and disposal of solid waste and RDF fuel. The development of retail market technologies is analyzed. The optimal parameters of the equipment are revealed

WASTE MANAGEMENT METHODS AND ENERGY PRODUCTION IN EUROPE AND IN RUSSIA

В работе представлен аналитический обзор ситуации в секторе «управление отходами» в Европе и в России. Составлена классификация способов утилизации отходов в разрезе энергоэффективности и экологической безопасности. Рассмотрены лучшие практики удаления отходов. Проведен анализ метода получения энергии из отходов и его роль в иерархии пирамиды управления отходами.The paper presents an analytical overview of the situation in the sector of "waste management" in Europe and in Russia. A classification of waste disposal methods in terms of energy efficiency and environmental safety has been compiled. The best practices of waste disposal are considered. An analysis is also made of the method of obtaining energy from waste and its role in the hierarchy of the waste management pyramid