Influence of accelerator energy parameters and silicon carbide microparticle sizes on the changes in magnetic field induction during their acceleration

This article contains the microparticle accelerator scheme, the methods, and the results of practical study of magnetic field induction and electromagnetic radiation formed during explosion product ionization and energy accumulation during explosive charge detonation, as well as the influence of some process parameters on its change. The purpose of this work is to study the influence of accelerator energy parameters and silicon carbide microparticle sizes on the change in magnetic field induction during their acceleration. The influence of technological parameters on the electrodynamic properties of the ionization process of a complex chemical system, which is condensed EXPLOSIVES, was studied by the developed method based on the Hall effect with the use of the developed semiconductor Hall sensors and a special measuring complex. The average magnetic field induction value is 48 MT. The influence of the energy parameters of the accelerator (explosive charge mass), as well as of the size of microparticles introduced into the explosion products (PV) on the electrodynamic properties of the processes of ionization and acceleration of microparticles was determined by measuring and calculating magnetic field induction. Practical results were obtained and confirmed the particle size influence on the plasma state. With an increase in the particle size from 20 to 100 microns, the induction value increases to 50 MT and decreases sharply with a change in the size from 150 to 300 microns. The obtained dependences are the technological characteristics of the process of processing materials by high-speed flows of microparticles with the use of explosion energy, which can be adjusted to make the process manageable.

Mathematical Model of Tubular Linear Induction Motor

Problem of calculation of distribution of magnetic field induction in clearance of tubular linear induction motor (TLIM) is considered. Mathematical model is represented by Fredholm integral equations of second kind for complexes of electric field strength and density of coupled magnetization currents at interface of environments. Algorithm of calculation of distribution of magnetic field induction in TLIM clearance has been developed. Dependence of magnetic field induction in motor clearance on value of pole division is investigated. There is area of optimum pole pitch. Reliability of results of calculations on mathematical model is confirmed by their comparison with results obtained on physical model. Calculated dependence of induction on thickness of runner's iron circuit also has extreme character. Given model can be used at design stage of TLIM. Model allows calculating its optimal geometric dimensions based on criterion of maximum induction in motor clearance, taking into account physical properties of applied materials.

MOBILE MAGNETOMETER FOR RAPID TEST OF SATURATION MAGNETIZATION OF MAGNETIC NANOFLUIDS

Работа направлена на создание магнитометрического прибора для точного определения намагниченности насыщения магнитных наножидкостей и подобных по свойствам функциональных дисперсных материалов. В основе прибора лежит магнитометрический метод с холловскими преобразователями индукции, усовершенствованный с учетом особенностей физико-механических свойств жидкостей. Измерительная магнитная система прибора построена таким образом, чтобы с помощью постоянных магнитов можно было создавать однородное намагничивающее поле величиной до (2 ÷ 4)⋅10 А/м в рабочем зазоре, где установлена кювета с изучаемой магнитной наножидкостью. Под кюветой с магнитной наножидкостью в среднем ее сечении располагается преобразователь Холла, который служит для измерения напряженности намагничивающего магнитного поля. Второй преобразователь Холла, предназначенный для измерения индукции магнитного поля в веществе, установлен в канавке прямоугольного сечения и располагается по центру магнитной наножидкости в кювете. Относительная ошибка измерения намагниченности на приборе не превышала 2 % для магнитных наножидкостей с намагниченностью в диапазоне от 10 кА/м до 50 кА/м. Созданный прибор может использоваться для экспресс - измерений в лабораторных и промышленных условиях и не требует специальных профессиональных навыков. Показано, что аддитивная составляющая инструментальной погрешности измерений зависит от значений остаточного напряжения (ЭДС неэквипотенциальности), побочных гальваномагнитных эффектов и термо-ЭДС измерительного преобразователя. Мультипликативная составляющая связана с временной и температурной нестабильностью коэффициента преобразования и тока или напряжения питания. Методическая погрешность магнитометра вызвана тем, что для измерений индукции магнитного поля используется не полностью замкнутая магнитная цепь. Показано, что по своим метрологическим параметрам прибор отвечает международным стандартам на магнитные измерения магнитомягких материалов. Прибор позволил определить намагниченность коллоидных систем в магнитных полях начала парапроцессов, индивидуальную намагниченность наночастиц дисперсной фазы, агрегативную устойчивость коллоидов в магнитных и гравитационных полях, оценить размеры сольватной оболочки наночастиц. The work is aimed at creating a magnetometric device for accurate determining the saturation magnetization of magnetic nanofluids and similar properties of functional dispersed materials. The device is based on a magnetometric method with the Hall induction transducers, improved taking into account the peculiarities of the physical and mechanical properties of liquids. The measuring magnetic system of the device is designed in such a way that with the help of permanent magnets it is possible to create a uniform magnetizing field up to (2÷4)⋅10 A/m in a working gap where the cuvette with the studied magnetic nanofluid is installed. Under the cuvette with a magnetic nanofluid in its middle section is a Hall Converter, which serves to measure the strength of the magnetizing magnetic field. The second Hall Converter, designed to measure the magnetic field induction in a substance, is installed in a rectangular groove and is located in the center of the magnetic nanofluid in the cuvette. The relative error of measuring the magnetization on the device did not exceed 2% for magnetic nanofluids with a magnetization in the range from 10 kA/m to 50 kA/m. The created device can be used for Express measurements in laboratory and industrial conditions and does not require special professional skills. It is shown that the additive component of the instrumental measurement error depends on the values of the residual voltage (nonequipotential EMF), side galvanomagnetic effects and thermo - EMF of the measuring Converter. The multiplicative component is related to the time and temperature instability of the conversion coefficient and the current or voltage supply. The methodic error of the magnetometer is caused by the fact that not a fully closed magnetic circuit is used for measuring the magnetic field induction. It is shown that the device meets international standards for magnetic measurements of soft magnetic materials in terms of their metrological parameters. The device allowed us to determine the magnetization of colloidal systems in magnetic fields of a start paraprocess, individual magnetization of nanoparticles of the dispersed phase, the aggregative stability of colloids in magnetic and gravity fields to estimate the size of the solvation shell of the nanoparticles.

DEVELOPING AND CREATION OF GROUND TESTING SIMULATOR FOR ORIENTATION AND STABILIZATION SYSTEM OF POLYITAN NANOSATELLITES

The article under the heading "Developing and creation of ground testing simulator for orientation and stabilization system of PolyITAN nanosatellites" is devoted to the research of methods of developing of the specialized simulator for the nanosatellite orientation and stabilization system ground testing. This problem is showed on the example of simulator developed in the National Technical Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”. Ground testing of the orientation and stabilization system is critically important phase of the pre-flight preparation of the nanosatellite. In order to provide precise tests, the simulator described in this article was developed. Objective of the simulator is to create targeted magnetic field in assured volume, where flight of the nanosatellite is imitated, stabilization and orientation performances are tested. The introduction describes experience of the PolyITAN team in developing of nanosatellites, the tasks of the first two nanosatellites - PolyITAN-1 and PolyITAN-2 are revealed, the actuality of this research is highlighted. The main part reveals the order of development of the simulator for orientation and stabilization system ground testing in gradual and sector-wise way. First part shows construction decisions in the simulator’s configuration to ensure accomplishment of the simulator’s objective. Second part describes calculation of the number of turns and the diameter of the wire to provide required value of the modulus of the vector of magnetic field induction, which is created by the simulator. Next part is devoted to calculation of power required for power sources, increment of magnetic field induction as a function of the current increment is provided, what is very important for power source selection. Next part is a research of the uniformity sphere - working space of the simulator, which must provide enough volume for testing of the 3U nanosatellites of CubeSat format. Final part describes control system of the simulator.

Modeling of strain kinetics of damping viscoelastic magnetically controlled materials in creep mode

The results of experimental studies of strain kinetics of composite magnetically controlled materials in the creep mode with preliminary exposure and without exposure are described by the Burgers model with two elastic and two viscous parameters, which is a combination of viscoelastic Kelvin–Voigt and Maxwell models connected in series. The dependence of the model parameters on the magnetic field induction is determined. The values of elastic and viscous parameters increase with increasing magnetic field induction in the range up to 500 mT by one or two orders of magnitude. It was determined that the value of the viscous Maxwell parameter does not change after preliminary exposure in the field. The values of the other two elastic and viscous Kelvin–Voigt parameters increase with exposure in a magnetic field.