On the possibility of controlling the induced electromagnetic field caused by the movement of a charged ball in seawater

Современные вычислительные средства с помощью новейших компьютерных технологий дают возможность производить моделирование и расчёт научных и прикладных задач в самых разных сферах деятельности. Новые возможности, позволяют ставить и решать многие комплексные научные и технические задачи морской гео- и гидрофизики, среди которых особенно актуальны в настоящее время следующие: создание аппаратуры для изучения и измерения электрического и магнитного полей в воде; исследование электрических явлений в море для определения их связи с другими физическими процессами; изучение магнитогидродинамических процессов, возникающих из-за движения морской воды в магнитном поле Земли и многие другие. Некоторые прикладные задачи требуют физически верного описания движения заряженного твёрдого тела, как в проводящей среде, так и на границе раздела сред, например, «газ–жидкость». Кроме того, подобного рода движения могут происходить при наличии изменчивости физических (например, геомагнитного) полей, которые необходимо учитывать. Решение подобных задач стало возможным с помощью современных вычислительных комплексов. Однако при этом следует иметь в виду, что сложный характер взаимодействия гидродинамического и электромагнитного полей обуславливает необходимость рассмотрения достаточно упрощенных моделей, описывающих основные закономерности изучаемых явлений. В настоящей работе представлены результаты численного моделирования генерации индуцированного магнитного поля, вызванной колебательным движением твёрдого шара, с помощь вычислительного комплекса ANSYS.CFX. Заряженный шар совершает колебания в приповерхностном слое границы раздела «морская вода – воздух». Модельная постановка задачи позволяет лучше понять механизм генерации магнитного поля, обусловленный движением твёрдого заряженного тела в проводящей среде. Modern computing facilities with the help of the latest computer technologies make it possible to simulate and calculate scientific and applied problems in a variety of fields of activity. New opportunities make it possible to pose and solve many complex scientific and technical problems of marine geo- and hydrophysics, among which the following are especially relevant at present: the creation of equipment for the study and measurement of electric and magnetic fields in water; study of electrical phenomena at sea to determine their relationship with other physical processes; the study of magnetohydrodynamic processes arising from the movement of sea water in the Earth's magnetic field and many others. Some applied problems require a physically correct description of the motion of a charged solid, both in a conducting medium and at the interface between media, for example, “gas – liquid”. In addition, such movements can occur in the presence of variability of physical (for example, geomagnetic) fields, which must be taken into account. The solution of such problems has become possible with the help of modern computing systems. However, it should be borne in mind that the complex nature of the interaction of hydrodynamic and electromagnetic fields necessitates the consideration of rather simplified models that describe the basic laws of the studied phenomena. This paper presents the results of numerical simulation of the generation of an induced magnetic field caused by the oscillatory motion of a solid ball using the ANSYS.CFX computer complex. The charged ball vibrates in the near-surface layer of the "sea water - air" interface. The model formulation of the problem makes it possible to better understand the mechanism of magnetic field generation caused by the motion of a solid charged body in a conducting medium.

Conducting Medium Electrical Conductivity at High Current Density

The experimental research example of electrical characteristics of structurally heterogeneous thinlayer conductors (nickel, copper) at high current density (108--109 А/m2) is shown. This current density in conditions of the samples intensive cooling is sufficient for the process of irreversible, nonthermally activated deformation. The experiment results show that the conducting medium at high current density has essential nonlinearities expressed in nonlinear dependence of the samples electrical resistance from current density. With repeated current treatments of the samples the conductors' electrical resistivity decreases. The number of defects removed from the volume of material as a result of nickel foil treatment by electric current is estimated. It is shown that under conditions of highdensity direct electric current flow in microvolumes of homogeneous and inhomogeneous conducting media a volume charge can appear. The appearance of the volume charge in a conducting medium can be caused by interaction forces during the motion of electrons and ions. Due to the interaction forces between ions and electrons of basic material and impurities, additional local ionization occurs which is realized in nano-volumes of a conductor. In the case of heterogeneous medium, the volume charge depends on the nature of the specific conductivity distribution. In a homogeneous conductor the volume charge is proportional to the square of the current density in the sample

Optimal frequency for magnetic resonant wireless power transfer in conducting medium

In this article, we investigated the efficiency of a magnetic resonant wireless power transfer (MR-WPT) in conducting medium and found out an optimal frequency for designing the system. In conducting environment, the eddy current loss is generated by the high-frequency alternating currents in the coils. It is manifested by increased radiation resistance of resonator coil leads to decrease the quality factor (Q-factor), which reduces the wireless power transfer (WPT) efficiency in conducting medium. The Q-factor of the resonator coil strongly depending on the conductivity, frequency, and thickness of conducting block. Two MR-WPT systems operating at 10.0 MHz and 20.0 MHz are implemented to study the effect of conducting medium on efficiency. The achieved results indicated that the 20.0 MHz system has higher efficiency at a conductivity smaller than 6.0 S/m. However, at the larger conductivity, the 10.0 MHz system is more efficient. The results provide a method to determine the optimal frequency of a WPT system operating in the conducting medium with various conductivities and thickness blocks. This method can be used to design MR-WPT systems in numerous situations, such as autonomous underwater vehicles and medical implants.

Heat-Exchange Surface Calculation of Heat-Conducting Medium and Grain Trashed Heap

Для энергосбережения при сушке зерна в контактно-конвективной сушилке предлагается использовать тепло охлаждающей жидкости двигателя внутреннего сгорания. Жидкость поступает в трубки контактно-конвективной сушилки. Трубки теплоносителя расположены наклонно под углом 40° параллельно друг другу по всей ширине сушилки. Над ними, в шахматном порядке – паросборники. Над паросборниками установлен плавающий разравнивающий транспортёр, который изменяет своё положение в зависимости от объёма зерна в контактно-конвективной сушилке. Рассмотрена отдельная зерновка, движущаяся по поверхности трубки теплоносителя. В результате нагрева зерновки происходит её отпотевание – появление влаги на поверхности зерновки. Произведён теплотехнический расчёт поверхности теплообмена теплоносителя и зернового вороха, определено количество тепла, передающегося зерновому вороху в результате контактного теплообмена. Установлено, что использование тепла охлаждающей жидкости двигателя внутреннего сгорания в контактно-конвективной сушилке приводит к энергосбережению при сушке зерна. For energy saving at grain drying in contact-convection drier it is proposed to use heat of cooling liquid of internal combustion engine. The liquid enters the tubes of the contact-convection drier. Heat carrier tubes are set at an angle of 40 ° parallel to each other along the full width of the drier. There are steam headers staggering above them. An amphibious leveling carrier is installed above the steam headers which changes its position depending on the volume of grain in the contact-convection drier. Separate caryopsis moving along surface of heat-conducting medium tube is considered. As a result of the heating of the caryopsis its sweating occurs – the appearance of moisture on the surface of the caryopsis. Thermotechnical calculation of heat-exchange surface of heat-conducting medium and grain trashed heap is performed, amount of heat transferred to grain trashed heap as a result of contact heat exchange is determined. It has been found that using the cooling liquid heat of the internal combustion engine in the contact-convection drier leads to energy saving when drying grain.

Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell

Triethylenetetramine (TETA) and thiourea complexed Cobalt(II) (Co(II)) ions are used as cathode catalysts for proton exchanged membrane fuel cells (PEMFCs) under the protection of polyaniline (PANI) which can become a conducting medium after calcination. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra clearly reveal the presence of typical carbon nitride and sulfide bonds of the calcined Nitrogen (N)- or Sulfur (S)-doped co-catalysts. Clear (002) and (100) planes of carbon-related X-ray diffraction patterns are found for co-catalysts after calcination, related to the formation of a conducting medium after the calcination of PANI. An increasing intensity ratio of the D to G band of the Raman spectra reveal the doping of N and S elements. More porous surfaces of co-catalysts are found in scanning electronic microscopy (SEM) micropictures when prepared in the presence of both TETA and thiourea (CoNxSyC). Linear sweep voltammetry (LSV) curves show the highest reducing current to be 4 mAcm−2 at 1600 rpm for CoNxSyC, indicating the necessity for both N- and S-doping. The membrane electrode assemblies (MEA) prepared with the cathode made of CoNxSyC produces the highest maximum power density, close to 180 mW cm−2.

Influence of the probe dimensions on the display of the low-frequency dispersion of the earth’s electromagnetic properties for measure-ments in marine waters up to 100 m deep

The purpose of the study is to show the effect of the probe dimensions on the display of the low-frequency dispersion of the geological formations’ electromagnetic properties in transient measurements by electric lines in the axial area of the source for the water areas up to 100 m deep. The study analyzes the change in the transient signal, the finite difference, and the transform (the ratio of the above two) as a function of the length of the source (a horizontal grounded electric line (AB) 50 to 2,000 m), the receiver (a three-electrode electric line (MON) 50 to 2,000 m), and the distance between their centers (spacing) 100 to 4,000 m. The values obtained from the conductive and conductive polarizing models are compared for the identical probes installed at the same depth. The grounded electric line is located within the conducting medium with a conductive polarizable base. The conducting medium is associated with the seawater thickness in the marine shelves up to 100 m deep. The conductive polarizable base is a geological environment (earth) covered with a layer of water. The polarizability of the base is registered by introducing frequency-dependent electrical resistivity by the Cole-Cole formula. The calculations show the display of different transient components associated with the transient buildup and the earth’s low-dispersion properties caused by both galvanic and eddy currents. These components manifest themselves differently for the probes with different dimensions of the source line, receiving line, and spacing. Based on the calculations, it can be argued that in the time range from 1 ms to 16 s, at the probes that have different dimensions and are immersed in the water layer up to 100 m thick, the signal changes depending on the immersion depth for “small” installations (AB of 50 and 100 m), while there is no such dependence for the rest of the probes used in the calculations (AB of 250, 500, 1,000, and 2,000 m).