Щодо розрахунку деформацій зсуву в призматичних стержнях із полімерних матеріалів за умов розтягу з крученням

The process of creep of prismatic rods made of linear-viscoelastic polymeric materials under combined loading is considered. Defining equations that determine the relationship between strains, stresses and time are given in the form of a superposition of shear and bulk strain. The object of study is prismatic bars made of fiberglass ST-1. The area of linearity of the model is substantiated on the basis of the hypothesis of the existence of the creep function, which is built on the yield curves, a single diagram of long-term deformation and the statistical value of the quantile of statistics. The region of linear-elastic deformation is recognized based on the fulfillment of the condition of existence of a single creep function. The defining equations of the model contain a set of functions and coefficients determined from the basic experiments. On the basis of the relations between the kernels of the one-dimensional stress state, the parameters of the kernels under the condition of a complex stress state are determined. The linearity of viscoelastic properties is given by the Boltzmann-Voltaire equations. The fractional-exponential kernels of heredity are chosen as the kernels of heredity. The obtained values of the core parameters are used to calculate the creep deformations of prismatic bars made of ST-1 fiberglass under conditions of simultaneous tensile tension. Pages of the article in the issue: 115 - 118 Language of the article: UkrainianРозглядається процес повзучості призматичних стержнів з лінійно-в’язкопружних полімерних матеріалів за умов комбінованого навантаження. Визначальні рівняння, що описують залежність між деформаціями, напруженнями і часом, задаються у вигляді суперпозиції зсувної і об’ємної деформації. Об’єктом дослідження являються призматичні стержні зі склопластику СТ-1. Обґрунтовується область лінійності моделі, виходячи з гіпотези існування функції повзучості, побудованої по кривим податливості, єдиної діаграми довготривалого деформування і статистичного значення квантиля статистики. Визначається область лінійно-пружного деформування, виходячи з виконання умови існування єдиної функції повзучості. Визначальні рівняння моделі містять набір функцій і коефіцієнтів, що знаходяться з базових експериментів. На підставі співвідношень між ядрами одновимірного напруженого стану визначаються параметри ядер за умови складного напруженого стану. Лінійність в'язкопружних властивостей задається рівняннями Больцмана-Вольтера з дробово-експоненціальним ядром спадковості. Отримані значення параметрів ядер використовуються для розрахунку деформацій повзучості призматичних стержнів зі склоапластика СТ-1 за умов одночасної дії розтягу з крученням

Pозробка методу контролю елементів конструкції планеру повітряних суден в умовах експлуатації

The paper proposes to use a method of infrared pulse-echo inspection to control airframe designelements, made of polymeric composite materials under operators` conditions. The following is described:skeleton operation diagram of the given method, device structure and results of the preliminary researchesconfirming operation capacity of the method offeredПредложено использовать инфракрасный эхо-импульсный метод для контроля элементов конструкции планера, изготовленного из полимерных композицитных материаловЗапропоновано використовувати інфрачервоний ехо-імпульсний метод для контролю елементів конструкціїпланера, виготовленого з полімерних композитних матеріалі

Control Systems Depending on a Parameter

A nonlinear control system depending on a parameter is considered in a finite-dimensional Euclidean space and on a finite time interval. The dependence on the parameter of the reachable sets and integral funnels of the corresponding differential inclusion system is studied. Under certain conditions on the control system, the degree of this dependence on the parameter is estimated. Problems of targeting integral funnels to a target set in the presence of an obstacle in strict and soft settings are considered. An algorithm for the numerical solution of this problem in the soft setting has been developed. An estimate of the error of the developed algorithm is obtained. An example of solving a specific problem for a control system in a two-dimensional phase space is given.This research was supported by the Russian Science Foundation (project no. 19-11-00105)

How to restrain Auger recombination predominance in the threshold of asymmetric bi-quantum-well lasers

Both radiative and nonradiative processes which occur in the active region of GaInAs–GaInAsP–InP asymmetric multiple quantum-well (AMQW) heterolasers with two quantum wells of different width (4 and 9 nm) are described. Several possible processes of non-radiative Auger recombination which affect the temperature sensitivity of the lasing threshold are analyzed and the temperature dependencies of the investigated processes are presented. For the above-mentioned AMQW heterostructure, it is shown that the influence of the Auger recombination processes on the temperature behaviour of the lasing threshold can be restrained by operation at temperatures lower than 340 K and the cavity losses which do not exceed 60 cm-1

Auger Recombination Processes and Threshold Conditions in Asymmetric-Multiple-Quantum-Well Heterostructure Lasers

Different possible processes of non-radiative Auger recombination which occur in the active region of quantum-well lasers are analyzed and the temperature dependence of the lasing threshold in the GaInAs-GaInAsP-InP bi-quantum-well heterolasers with different widths of the quantum wells (4 and 9 nm) is determined. Activated behavior of the Auger recombination is mentioned and respective effective parameters of the processes are calculated. For described asymmetric quantum-well heterostructure lasers, it is shown that the influence of the Auger recombination processes on the temperature behavior of the lasing threshold is not essential until the temperature of the active region is lower than 360 K and the cavity losses do not exceed 80 cm-

Temperature dependence of the threshold and Auger recombination in asymmetric quantum-well heterolasers

The temperature dependence of the lasing threshold in the GaInAs-GaInAsP-InP bi-quantum-well heterolasers with different widths of the quantum wells (4 and 9 nm) has been determined. Processes of non-radiative Auger recombination which occur in the active region of the quantum-well lasers have been included into consideration. The analytical approach for the evaluation of the characteristic temperature of the lasing threshold is presented. For described asymmetric quantumwell heterostructure lasers, it is shown that the influence of Auger recombination processes on the temperature behavior of the lasing threshold is not essential until the temperature of the active region is lower than 360 K and the cavity losses do not exceed 80 cm-

Geomagnetic storms and the occurrence of phase slips in the reception of GPS signals

We have investigated a dependence of the relative density of GPS phase slips on the geomagnetic disturbance level. The study is based on using Internet-available selected data from the global GPS network, with the simultaneously handled number of receiving stations ranging from 160 to 323. The analysis used four days from the period 1999-2000, with the values of the geomagnetic field disturbance index Dst from 5 to – 300 nT. During strong magnetic storms, the relative density of phase slips on mid-latitudes exceeds that for magnetically quiet days by one-two orders of magnitude as a minimum, and reaches a few percent of the total density of observations. Furthermore, the level of phase slips for the GPS satellites located on the sunward side of the Earth was by a factor of 5-10 larger compared with the opposite side of the Earth. The level of slips of L 1 phase measurements at the fundamental GPS frequency is at least one order of magnitude lower than that in L 1 – L 2 measurements. The slips of L 1 – L 2 measurements are most likely to be caused by the high level of slips of L 2 phase measurements at the auxiliary frequency. As an alternative, we developed and tested a new method for determining TEC variations using only data on the pseudo-range and phase measurements at fundamental frequency L 1 . The standard deviation of the TEC variations which were obtained in phase measurements at two frequencies, L 1 – L 2 , and at fundamental frequency L 1 , does not exceed 0.1 TECU, which permits this method to be used in strong disturbance conditions when phase slips at auxiliary frequency L 2 are observed

Design of Pre-Dumping Ring Spin Rotator with a Possibility of Helicity Switching for Polarized Positrons at the ILC

The use of polarized beams enhance the possibility of the precision measurements at the International Linear Collider (ILC). In order to preserve the degree of polarization during beam transport spin rotators are included in the current TDR ILC Lattice. In this report some advantages of using a combined spin rotator/spin flipper are discussed. A few possible lattice designs of spin flipper developed at DESY in 2012 are presented.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS15), Whistler, Canada, 2-6 November 201

Suppression of magnetism under pressure in FeS: A DFT+DMFT study

We investigate the evolution of the magnetic properties in FeS under pressure and show that these cannot be explained solely in terms of the spin-state transition from a high to low spin state due to an increase of the crystal field. Using a combination of density functional theory and dynamical mean-field theory (DFT+DMFT), our calculations show that at normal conditions the Fe2+ ions are in the 3d6 high-spin (S=2) state, with some admixture of a 3d7L (S=3/2) configuration, where L stands for the ligand hole. Suppressing the magnetic moment by uniform compression is related to a substantial increase in electron delocalization and occupation of several lower spin configurations. The electronic configuration of Fe ions cannot be characterized by a single ionic state, but only by a mixture of the 3d7L,3d8L2, and 3d9L3 configurations at pressures ∼7.5GPa. The local spin-spin correlation function shows well-defined local magnetic moment, corresponding to a large lifetime in the high spin state at normal conditions. Under pressure FeS demonstrates a transition to a mixed state with small lifetimes in each of the spin configurations. © 2017 American Physical Society

Molecular packing, piezo- and pyroelectric properties of tert-butyl N-(tert-butoxycarbonyl)-(S)-prolinamide

The work was financially supported by the Russian Foundation for Basic Research (grant no. 16-33-60122). The equipment of the Ural Centre for Shared Use “Modern Nanotechnologies” UrFU and Centre for Joint Use “Spectroscopy and Analysis of Organic Compounds” was used