The Influence of the Parameters of a Ferromagnetic Shield on the Efficiency of a Linear Induction-Dynamic Converter

The influence of the geometrical parameters of a ferromagnetic shield on the operation of a linear induction-dynamic converter was investigated with the help of the integral efficiency parameter. Values of geometrical parameters of the shield with the best converter performance for different means of determining key indicators were obtained by the local optimization method. Experiments have proven that, depending on the geometrical parameters, the ferromagnetic shield increases the armature speed up to 47%, decreases the maximum current in the inductor down to 35%, and increases the time to peak current up to 21% as com pared with the converter without the ferromagnetic shield. Satisfactory concurrence was obtained between experimentally measured and calculated parameters of the linear induction-dynamic converter

The Thermal State of an Electromechanical Induction Converter with Impact Action in the Cyclic Operation Mode

A mathematical model is developed for an electromechanical induction converter of impact action, and its operation modes are investigated. It is shown that stabilization of exceeding the temperature of active elements at a significant number of operation cycles can be provided by intense cooling of the steel work of the inductor winding and an increase in the pulse period

Temperature field in the vacuum chamber of a ballistic gravimeter

A mathematical model for the temperature field of a ballistic gravimeter is developed based on a thermal conductivity boundary value problem to be solved by the finite element method. Genetic algorithms and the Nelder-Mead method are used to develop a way for synthesizing the parameters of electric heaters to reduce the temperature gradients inside the vacuum chamber of a ballistic gravimeter and to improve its technical parameters

Concept of an induction-dynamic catapult for a ballistic laser gravimeter

A design is proposed for an inductive-dynamic catapult in a ballistic laser gravimeter with a fixed inductor and an electrically conducting armature that moves together with the test object along a vertical axis. The catapult ensures improved accuracy of the gravimeter through direct conversion of electrical into kinetic energy. The electrical circuit of the catapult provides two successive current pulses to the inductor for launching and braking of the armature during the operating cycle

Influence of External Electromagnetic Screen on Efficiency of Impact Electromechanical Converter of Disk Configuration

Based on a mathematical model, the influence of the disk and cylindrical parts of the outside of the electromagnetic screen on the efficiency of a given electromechanical converter taking into consideration the electrodynamics that acts on them is revealed. The basic theoretical concepts and reliability of the math ematical model are confirmed by experimental research

A ballistic laser gravimeter for a symmetrical measurement method with the inductive-dynamic catapult and auto-seismic vibration preventing

A ballistic laser gravimeter (BLG) with a symmetrical measurement method of the gravity acceleration (GA) is considered. Special treatment is given to the problem of eliminating the measurement error due throw of the catapult when it speeds up the test body (TB). It is possible to decrease the indicated errors thanks to the use of the induction and dynamic catapult. However, a short-term boost catapult generates vibrations of the basement (i.e. a pillar) and the mechanical elements of the gravimeter, what causes auto-seismic (i.e. recoil-related) component of the measurement error. To reduce them it is proposed to launch the TB with the help of a massive platform, installed on a light spring. It is shown, that the considered BLG can provide auto-seismic component of the measurement error of less than 1 μGal. With the reduction of the light spring constant the auto-seismic component of GA measurement uncertainty is reduced. The value of this measurement error can be reduced by the use of damping in the system of BG protection from auto-seismic fluctuations. A concept of BLG with induction-dynamic catapult for symmetric method of gravitational acceleration measuring is presented. The concept is based on using electromagnetic compensator of stiffness

Effect of self-seismic oscillations of the foundation on the readout of a ballistic gravimeter with an induction-dynamic catapult

A mathematical model is developed for the vertical oscillations produced in the base–foundation system of a laser ballistic gravimeter with an induction-dynamic catapult and a symmetric configuration for measuring the acceleration of gravity. Analytic expressions are obtained for the force pulse acting on the foundation during acceleration of the test body that describe the oscillations in the mechanical system of the ballistic laser gravimeter. The effects of the measurement duration and the damping coefficient of the foundation on the results of measurements of the acceleration of gravity are studied

ИССЛЕДОВАНИЕ ЛИНЕЙНОГО ИМПУЛЬСНО-ИНДУКЦИОННОГО ЭЛЕКТРОМЕХАНИЧЕСКОГО ПРЕОБРАЗОВАТЕЛЯ ПРИ РАЗЛИЧНЫХ СХЕМАХ ПИТАНИЯ ИНДУКТОРА

Purpose. The goal of the paper is to investigate the influence of the power circuits of the linear pulse-induction electromechanical converters (LPIEC), which form the current pulse of excitation of the inductor from the capacitive energy storage (CES), to its electromechanical parameters. Methodology. A circuit mathematical model of LPIEC was developed, on the basis of which recurrence relations were obtained for calculating the interrelated electromagnetic, mechanical, and thermal parameters of the LPIEC. This model makes it possible to calculate the LPIEC parameters for various power circuits, the inductor of which is excited by the CES. Results. It is established that electromechanical LPEC parameters with power circuit forming an aperiodic current excitation pulse of an inductor are better than in LPIEC with excitation of an inductor by an unipolar current pulse, but worse than in LPIEC with excitation of an inductor by a vibrationally damped current pulse. In this converter, during operation, the inductor is heated most, and the armature is heated least. It is established that in LPIEC with power circuit that forms an aperiodic current pulse of excitation of an inductor with the connection of an additional CES, all electromechanical parameters are higher in comparison with the LPIEC with a power circuit that forms a vibrationally damped current excitation pulse of the inductor. However, in this LPIEC the excess of the temperatures of the active elements increases, especially strongly in the inductor, and the efficiency of the converter decreases. Originality. For the first time, the LPIEC has been investigated using the power circuit that forms an aperiodic current pulse of excitation of an inductor with the connection of an additional CES. It is established that in this LPIEC all electromechanical parameters are higher than for LPIEC with power circuits forming an unipolar or oscillating-damped current excitation pulse of the inductor. Practical value. In the LPIEC with power circuit that forms an aperiodic current pulse of excitation of the inductor with the connection of an additional CES, the electromechanical LPIEC parameters increase. This increases the temperature rise of the inductor, and the temperature rise of the armature decreases. The effectiveness of this LPIEC is also reduced.На основе разработанной цепной математической модели получены рекуррентные соотношения для расчета взаимосвязанных электромагнитных, механических и тепловых параметров линейного импульсно-индукционного электромеханического преобразователя (ЛИИЭП). Показано, что электромеханические показатели ЛИИЭП со схемой питания индуктора, формирующей апериодический токовый импульс возбуждения, лучше, чем у ЛИИЭП с возбуждением индуктора однополярным токовым импульсом, но хуже, чем у ЛИИЭП с возбуждением индуктора колебательно-затухающим токовым импульсом. В данном преобразователе в процессе работы наиболее сильно нагревается индуктор и наименее нагревается якорь. Показано, что в ЛИИЭП со схемой питания индуктора, формирующей апериодический токовый импульс возбуждения с подключением добавочного емкостного накопителя энергии, все электромеханические показатели выше по сравнению с ЛИИЭП со схемой питания индуктора, формирующей колебательно-затухающий токовый импульс возбуждения. Однако в этом ЛИИЭП возрастают превышения температур активных элементов, особенно сильно – индуктора и снижается КП

KrioBlastTM as a new technology of hyper-fast cryopreservation of cells and tissues. Part 2. Kinetic vitrification of human pluripotent stem cells and spermatozoa

Pilot experiments on kinetic vitrification of human pluripotent stem cells and spermatozoa using a KrioBlastTM-2 without penetrating cryoprotectants have shown high survival of cells (75-85% in both cases