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

ВЛИЯНИЕ ПАРАМЕТРОВ ЯКОРЯ ЛИНЕЙНОГО ИМПУЛЬСНОГО ЭЛЕКТРОМЕХАНИЧЕСКОГО ПРЕОБРАЗОВАТЕЛЯ НА ЕГО ЭФФЕКТИВНОСТЬ

Purpose. The evaluation of the effect of armature parameters on the efficiency of a linear pulsed electromechanical converter, taking into account the power, speed, constructive and environmental parameters. Methodology. First, the height of the electrically conductive, coil and ferromagnetic armature of a linear pulse electromechanical converter is determined, at which the highest velocity develops. An integral efficiency index is introduced, which takes into account, in a relative way, the power, speed, energy, electrical and field characteristics of the converter. Variants of the efficiency evaluation strategy are used that take into account the priority of each indicator of a linear pulse electromechanical converter using the appropriate weighting factor in the integral efficiency index. Results. A mathematical model of a linear pulsed electromechanical converter is developed. It is established that as the height of the electroconductive, coil and ferromagnetic armature increases, the force pulse increases. The greatest speed develops with the use of a coil armature, and the smallest with an electroconductive armature. In the converter with coil and ferromagnetic armature, practically the same values of the electrodynamic and electromagnetic force pulse are realized, while in the converter the electrodynamic force is 1.52 times smaller in the converter by the electrically conductive armature. It is established that with all efficiency evaluation strategies, the converter with a coil armature is the most effective, even in spite of its constructive complexity, and the converter with a ferromagnetic armature is the least effective, although it is constructively the simplest. Originality. For the first time, using the integral efficiency index, which takes into account the power, speed, energy, electrical and field indices in a relative way, it is established that with all efficiency evaluation strategies, the converter with a coil armature is the most effective, and the converter with a ferromagnetic anchor is the least effective. Practical value. The height of the electrically conductive, coil and ferromagnetic armature of a linear pulse electromechanical converter is determined, at which the highest speed develops. It is shown that when using an electrically conductive armature, the value of the electrodynamic force pulse is lower than when using a coil and ferromagnetic armature. It is established that the converter with a coil armature is the most efficient, and the converter with a ferromagnetic armature is the least effective.Разработана математическая модель линейного импульсного электромеханического преобразователя (ЛИЭП), описывающая быстропротекающие и взаимосвязанные электромагнитные и электромеханические процессы, проявляющиеся при перемещении якоря относительно индуктора. Показано, что при увеличении высоты электропроводящего, катушечного и ферромагнитного якорей ЛИЭП происходит увеличение импульса силы. Наибольшая скорость развивается в ЛИЭП с катушечным якорем, а наименьшая – в ЛИЭП с электропроводящим якорем. В ЛИЭП с катушечным и ферромагнитным якорями реализуются практически одинаковые значения импульса электродинамической и электромагнитной силы, а в ЛИЭП с электропроводящим якорем импульс электродинамической силы в 1,52 раза меньше. Введен интегральный показатель эффективности, который в относительном виде учитывает силовые, скоростные, энергетические, электрические и полевые показатели. Установлено, что при всех стратегиях оценки эффективности наиболее эффективным является ЛИЭП с катушечным якорем, а наименее эффективным является ЛИЭП с ферромагнитным якорем

ЭЛЕКТРОМЕХАНИЧЕСКИЕ ПРОЦЕССЫ В ЛИНЕЙНОМ ИМПУЛЬСНО-ИНДУКЦИОННОМ ЭЛЕКТРОМЕХАНИЧЕСКОМ ПРЕОБРАЗОВАТЕЛЕ С ПОДВИЖНЫМ ИНДУКТОРОМ И ДВУМЯ ЯКОРЯМИ

Purpose. The purpose of the paper is to determine the influence of the height of the mobile and stationary disk electrically conductive armatures covering the movable inductor on the electromechanical processes of linear pulsed-induction electromechanical converter (LPIEC). Methodology. With the help of the developed mathematical model that describes electromechanical and thermal processes of LPIEC, the influence of the heights of the armatures on electromechanical processes, the values of the electrodynamic forces acting on the inductor and armature, and the moving speed of the movable armature (MA) is established. Results. It is shown that if the height of the stationary armature (SA) is twice the height of the MA, then the inductor at the initial instant of time is acted upon by electrodynamics forces pressing it to the SA, and the displacement of the inductor begins with a delay of 0.35 ms. If the height of the MA is twice the height of the SA, then the electrodynamics forces act on the inductor at the initial instant of time, repelling it from the SA, and its movement begins with a delay of 0.1 ms. If the heights of the SA and the MA are equal, then until the time 0.15 ms on the inductor, the electrodynamics forces practically do not act and the inductor moving relative to the SA begins with a delay of 0.25 ms. Originality. The effect of the geometric parameters of the SA and MA on the velocity of the inductor moving relative to the SA, MA relative to the inductor and the MA relative to the SA is established. It has been established that the highest velocity of the MA relative to the SA develops the lowest MA, and the height of the SA does not affect it practically. However, with the increase in the height of the MA, the effect of SA begins to affect. In this case, it is expedient to select the height of the SA to be 0.4-0.42 of the height of the inductor. Practical value. It is shown that as the weight of the actuating element increases, the currents in the active elements of the LPIEC increase, the induction velocities of the inductor relative to the SA and the MA decrease relative to the inductor. At the same time, the maximum the electrodynamic forces values acting on the inductor decrease, and the armatures increase. Moreover, the maximum the electrodynamic forces acting on the MA are less than similar forces acting on the SA.Разработана математическую модель, которая описывает электромеханические процессы в линейном импульсно-индукционном электромеханическом преобразователе с подвижным индуктором, взаимодействующим со стационарным якорем (СЯ) и подвижным якорем (ПЯ), ускоряющим исполнительный элемент. Установлено влияние высот якорей на электромеханические процессы в преобразователе. Если высота СЯ в два раза больше высоты ПЯ, то на индуктор в начальный момент времени действуют электродинамические усилия (ЭДУ), прижимающие его к СЯ и перемещение индуктора начинается с задержкой 0,35 мс. Если высота ПЯ в два раза больше высоты СЯ, то на индуктор в начальный момент времени действуют ЭДУ, отталкивающие его от СЯ, и его перемещение начинается с задержкой 0,1 мс. Если высоты СЯ и ПЯ равны, то до момента времени 0,15 мс на индуктор практически не действуют ЭДУ и перемещение индуктора начинается с задержкой 0,25 мс. Установлены комбинации геометрических параметров якорей, при которых действуют как наибольшие, так и наименьшие импульсы ЭДУ. Наибольшие скорости развивает наиболее низкий ПЯ, причем высота СЯ на них практически не влияет. С увеличением массы исполнительного элемента происходит увеличение токов в активных элементах преобразователя и уменьшение скоростей индуктора и ПЯ. При этом максимальные значения ЭДУ, действующих на индуктор, уменьшаются, а на якоря – увеличиваются

INVESTIGATION OF LINEAR PULSE ELECTROMECHANICAL CONVERTER OF INDUCTION TYPE WITH DOUBLE ARMATURE INTENDED FOR DESTROYING INFORMATION ON SSD STORAGE DEVICE

Purpose. The goal of the paper is to determine the influence of the linear pulse electromechanical converter (LPEC) parameters with a double armature on its electrical, power and temperature indices and experimental verification of the proposed design for an information destruction device in a flat SSD storage device. Methodology. Using the mathematical model that takes into account interrelated electrical, magnetic, thermal and mechanical processes, the influence of geometric parameters on the electrodynamic characteristics and the indices of the induction type LPEC with a double armature spanning the inductor from opposite sides is investigated. Results. It is shown that the currents in the inductor and armature change in accordance with the oscillation-damping law practically in antiphase. The maximum value of the current density in the inductor is 215.8 A/mm2, and in each of the identical parts of the double armature it is 299.7 A/mm2. The maximum value of electrodynamic forces (EDF) acting in opposite directions on the front and rear of the double armature is 11.99 kN, and the value of the EDF pulse is 4.59 N∙s. Originality. It is established that with axial removal of the rear part of the armature from the inductor, the maximum current densities in the inductor decrease, in the front part of the armature increase, and in the rear part of the armature decrease. The maximum value and the pulse of the EDF between the armature parts decrease. With an increase in the number of turns in the inductor and a decrease in the thickness of the copper bus, all the basic indicators of the LPEC increase. With an increase in the number of turns of the inductor from 26 to 56, the maximum EDF value acting between the parts of the armature increases almost 3 times, and the magnitude of the EDF pulse is 3.3 times. With an increase in the width of the copper bus and the width of the inductor, the main indicators of the LPEC decrease. With an increase in the width of the inductor from 10 mm to 20 mm, the maximum EDF between the armature parts decreases by 1.3 times, and the value of the EDF pulse decreases by 1.2 times. Practical value. Based on the conducted studies, an induction-type LPEC model with a double armature was designed and tested experimentally, designed to destroy information located on a solid-state digital SSD storage device

The Period Changes of the Cepheid RT Aurigae

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit.Comment: Accepted for publication in PASP (November 2007

A search for W bb and W Higgs production in ppbar collisions at sqrt(s)=1.96 TeV

We present a search for W b \bar{b} production in p \bar{p} collisions at sqrt{s}=1.96 TeV in events containing one electron, an imbalance in transverse momentum, and two b-tagged jets. Using 174 pb-1 of integrated luminosity accumulated by the D0 experiment at the Fermilab Tevatron collider, and the standard-model description of such events, we set a 95% C.L. upper limit on W b \bar{b}$production of 6.6 pb for b quarks with transverse momenta p_T^b > 20 GeV and b \bar{b} separation in pseudorapidity-azimuth space Delta R_bb > 0.75. Restricting the search to optimized b \bar{b} mass intervals provides upper limits on$WH$production of 9.0$-$12.2 pb, for Higgs-boson masses of 105$-$135 GeV.Comment: 7 pages, 4 figures, 1 table, submitted to Physical Review Letter

Measurement of the Ratio of B+ and B0 Meson Lifetimes

The ratio of B+ and B0 meson lifetimes was measured using data collected in 2002-2004 by the D0 experiment in Run II of the Fermilab Tevatron Collider. These mesons were reconstructed in B -> mu+ nu D*- X decays, which are dominated by B0, and B ->mu+ nu D0bar X decays, which are dominated by B+. The ratio of lifetimes is measured to be t+/t0 = 1.080 +- 0.016(stat) +- 0.014(syst).Comment: 7 pages, 2 figures, LaTeX, to be submitted to Physical Review Letter

A Search for the Flavor-Changing Neutral Current Decay B0_s -> mu^+mu^- in pp(bar) Collisions at \sqrt{s} = 1.96 TeV with the D0 Detector

We present the results of a search for the flavor-changing neutral current decay B0_s -> mu+ mu- using a data set with integrated luminosity of 240 pb^{-1} of pp(bar) collisions at sqrt{s}=1.96 TeV collected with the D0 detector in Run II of the Fermilab Tevatron collider. We find the upper limit on the branching fraction to be Br(B0_s -> mu+ mu-) \leq 5.0 x 10^{-7} at the 95% C.L. assuming no contributions from the decay B0_d -> mu+ mu- in the signal region. This limit is the most stringent upper bound on the branching fraction B0_s -> mu+ mu- to date.Comment: 7 pages, 3 figures, LaTeX, to be submitted to Physical Review Letters, minor changes to text, reference adde

ОСОБЕННОСТИ ПОЛУЧЕНИЯ ЩЕЛОЧНО-СИЛИКАТНЫХ ТЕПЛОИЗОЛЯЦИОННЫХ МАТЕРИАЛОВ

The paper presents investigation results pertaining to peculiar features of thermal insulation material production and description of their property study. The production process presupposes  swelling of alkaline-silicate raw materials at temperature 300–500 °C of mixes, are presented. Представлены результаты исследований особенностей получения теплоизоляционных материалов, создаваемых вспучиванием при температуре 300–500 °С щелочно-силикатных сырьевых смесей, и изучения их свойств