Induction Vector Research Articles

Modeling of magnetic fields and signals of a ferromagnetic pipe flaw detector induced by a through hole defect

A numerical model has been developed for interaction of the magnetizing field of a short solenoid with a ferromagnetic pipe exhibiting a through hole in the wall, which takes into account nonlinear magnetic properties of the test object. This model was used to calculate spatial distribution of magnetic induction in the pipe wall and spatial distribution of the components of the magnetic induction vector near the pipe surface with a through hole. The validity of the numerical model was confirmed by physical modeling results. The results of theoretical and experimental studies were used to develop a simplified analytical model that describes behavior of the magnetic field of the defect and the electrical signal of the induction transducer of a magnetic flaw detector that implements the method of magnetic flux leakage. It is shown that the dependence of the signal of the induction transducer induced by the through hole on the gap is close to a linear one, and its dependence on the hole diameter is close to a quadratic one. The results obtained in the study can be used for creation, numerical modeling and measurement of magnetic fields.

Accounting of the magnetic field of the power supply system of a power-capacitive technical object

The paper shows the approach and the result of taking into account the mutual influence of on-board subsystems of a complex technical object along the DC power supply circuits. Technical objects are understood as a mobile, energy-intensive vehicle, such as an aircraft, a surface or submarine vessel, or a railway locomotive with strong magnetic fields. The aim of the work is to create a simple and intuitive tool for mathematical modeling of the magnetic field vector at an arbitrarily specified observation point. The task is being solved in order to improve the accuracy of magnetic measurements on board, in particular, in navigation problems. On-board DC networks are considered, to which the approach of mathematical modeling is applied. The disadvantages of commercial programs of a similar purpose are noted. The binding of the objects under consideration to the general coordinate system is described. An analytical algorithm for calculating the magnetic field vector from the on-board cable network with a pronounced 3D trajectory is shown. Examples of visualization of the simulation results are given. An algorithm for calculating the induction vector based on the Biot-Savard law is considered. The algorithm for the analytical solution of the problem is described in detail. A specific power cable of the on-board network is considered. The cable is given by a set of straight conductors with current. The ways of future improvement of the created product with the transition from one observation point to the field map in a given three-dimensional zone of arbitrary position, volume and orientation are outlined. The obtained result is considered as an element of the procedure for achieving electromagnetic compatibility of energy-intensive and highly sensitive subsystems of a modern complex technical object.

Modeling of electrodynamic processes by means of mechanical analogies

AbstractThis study continues the line of earlier research in mechanical models of electrodynamic processes suggested in previous works. The basic steps we take to construct these models are: to formulate equations of a special type Cosserat continuum, and then to suggest analogies between quantities characterizing the stress–strain state of the continuum and quantities characterizing electrodynamic processes. In addition to the previously introduced mechanical analogies of the electric field vector and the magnetic induction vector, in this paper we provide mechanical analogies of the magnetic field vector, the electric induction vector, the electric current density and the electric charge density. In the framework of the suggested model, we obtain a set of differential equations that coincide with the first Maxwell's equation (the one with the displacement current term), the Gauss law for electric field and the charge conservation law. As a debatable question, we discuss the possibility of modifying the Maxwell–Faraday equation and the Gauss law for magnetic field.

Spatial-temporal change of the geomagnetic field: environmental aspect

The geomagnetic field, along with other environmental factors, is a necessary component of life on the Earth. Currently, there are relevant ecological standards for the values of constant and variable fields. Taking them into account, it is possible to determine the conditions necessary for the normal functioning of biological objects in general and humans in particular. In a number of regulations, certain limit values for a constant magnetic field are introduced, as well as the maximum permissible time of a human being stay in such fields. In this regard, the article considers the spatiotemporal change in induction B on the Earth’s surface using the example of its main magnetic field according to the international model IGRF-13 for the time interval 1950—2020. In more detail for this time interval, the induction module B and its perturbation were analyzed for geomagnetically different regions that are, namely, the territories of Ukraine, of Yamal (Russia) and around the Ukrainian Antarctic Akademik Vernadsky station. For the planet in whole, a significant decrease in the geomagnetic field is shown, against the background of which its sharp jumps are observed (in 1960—1965, 1980—1985 and in 2000—2005), and after 2005 to the present, a deceleration in the decrease of the geomagnetic field is observed. Against the background of a decrease in the geomagnetic field of the planet, areas with extreme changes both in the direction of increase (Ukraine, Yamal) and decrease (AV station) are distinguished. The spatiotemporal changes in the geomagnetic field detected on the Earth’s surface determine the structure and dynamics of its magnetosphere, which by-turn affects the nature of the interaction with it of solar wind substance and of cosmic radiation, as well as the flow altitudes of magnetospheric and ionospheric currents. According to the distribution of the geomagnetic field anomalies on the surface of the planet, as well as to their changes over the studied time interval, regions with different (as compared with proposed ecological norms) values of the constant magnetic field and its disturbances are distinguished. In particular, for the epoch of 2020, for the territory in the vicinity of the AV station, the induction vector module B is on average 15,000 nT less than its value for the territory of Ukraine and 25,000 nT — of Yamal. Significant changes in the geomagnetic field were determined: an increase of 1765 nT for Ukraine, 1418 nT for Yamal and a decrease of — 7081 nT in the vicinity of AV station. At the same time, the perturbation of the geomagnetic field of the territory of Ukraine is within its ecological norm, deviates from it in the direction of increase on the Yamal Peninsula, and near the AV station it will soon go beyond its limits in the direction of decrease, while maintaining modern field changes.

Oblique magnetic field influence on the wakefield in complex plasmas

abstractThe results of an investigation of the wakefield around a stationary charged grain in an external magnetic field with non-zero transverse component with respect to the ion flow direction is presented. In contrast to the previously reported significant suppression of the wake oscillations due to the magnetic field applied along the flow, the wake potential exhibits long range recurrent oscillations in the presence a of transverse flow to the magnetic field. Extensive analysis for a wide range of parameters elucidate a strong dependence of the wake on the orientation of the magnetic field in the sonic and supersonic regimes by manifesting sensitivity to even a meager deviation of magnetic field from the longitudinal direction. The impact of the orientation and strength of magnetic field on the wake behavior is assessed. The deviation of the magnetic field induction vector from the longitudinal to ion flux direction leads to the wakefield with two positive peaks split in the transverse to ion flow direction in the downstream region; similar to that of the ultracold ions wake without magnetic field [(2020) New J. Phys. 22 033028].

Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications

The northern part of the Fennoscandian shield records several Palaeoproterozoic phases of rifting, crustal shortening, metamorphism and structural reactivation. The geologic history has left behind a complex crustal geoelectric structure as evidenced by magnetotelluric (MT) data from the central Finnish Lapland acquired in the context of the MaSca-project in 2014. The data are characterized by strong 3-D effects such as high phase tensor skew values and anomalous induction vectors. Interestingly, however, at the same time a dominant E-W principal direction from the phase tensor data can be inferred. 3-D conductivity models derived using the ModEM code display high crustal conductance (> 10,000 S) in the vicinity of the Central Lapland Greenstone Belt, the Peräpohja Belt and the Kuusamo Belt. Conductors in the northern and southern part of the study area are separated by a resistor coinciding with the Central Lapland Granitoid Complex. A remarkable feature is an arc-shaped conductor inside the northern part of the Central Lapland Granitoid Complex, which continues into the Central Lapland Greenstone Belt in the north. The conductor is associated with a major induction vector anomaly and also coincides with extreme responses (negative phase tensor principal values), which are discussed in an accompanying paper. The conductive structures in the models are interpreted as deeply buried graphite and sulphide bearing metasedimentary rocks or as reactivated Archaean shear zones. The revealed geoelectric structures also partly correlate with seismic reflection and other geophysical data from the area. A possible explanation for the observed pervasive E-W principal direction of the phase tensor data could be the aulacogen (failed rift) suggested in recent tectonic evolution models.

Complex plasma in a stratified glow discharge in a strong magnetic field

A dusty plasma was created in a stratified glow discharge in longitudinal magnetic fields above 1 T. Experimental conditions were selected and dust structures were first created in the neon working gas in the magnetic field range B = 1.1–2.2 T. Under realized conditions, the electron cyclotron radius is close to the dust particle radius, and the ion cyclotron radius is less than the Debye screening length. Images of dust structure cross sections perpendicular to the magnetic field were obtained. They contain about 10 particles. The dependence of the angular velocity of the dust structure rotation for its widest cross section on magnetic field was measured. The direction of the angular velocity vector coincides with the direction of the magnetic induction vector. In contrast to the previously obtained dependence of the rotation velocity on magnetic field in the region B < 1 T, at B > 1 T the rotation angular velocity ceases to grow, reaching a value of about 3 rad s−1. To explain the experimental results on the dust structure rotation velocity, an analytical model of the rotation mechanism is proposed. The model is based on the concept of eddy currents in striations and the influence of the magnetic field on the striation length. The obtained estimates of the rotation velocity are in a good agreement with the experimental data.

On the influence of magnetic field on electrodeposition of Ni–TiO2 composites from a citrate baths

In this paper, we present the results of the study on the influence of electrolysis conditions including external magnetic field on the properties of Ni–TiO2 composite materials synthesized from a citrate bath. The influence of electrode potential, TiO2 concentration in the electrolyte, as well as the value of magnetic field induction vector on the deposition rate, composition, current efficiency, structure, surface states and morphology of the synthesized coatings is reported. The obtained results indicate possibilities of synthesis of composites containing up to 1.39 wt % of TiO2. Dependent on the applied electrolysis condition current efficiency amounts to from 38.1 to 45.5% for B = 0 T and from 46.3 to 53.1 for B = 1 T. The results of electrochemical studies as well as further characterization of synthesized materials indicate that the presence of the magnetic field strongly influenced the kinetics of the processes responsible for materials formation. Voltammetric, XRD and XPS analyses indicate simultaneous formation of hydrides and hydroxides during electrolysis.

Finite deformation analysis of isotropic magnetoactive elastomers

In this study, the large deformation analysis of the magnetoactive elastomers based on continuum mechanics approach has been conducted. First, the governing differential equations for the spatial configuration are presented. Stored energy density function defined with respect to the invariants of the right or left Cauchy–Green deformation tensor and the magnetic field induction vector is adopted to develop a material model for finite deformation of isotropic magnetoactive elastomers (MAEs). An isotropic magnetoactive sample with 15% iron particle volume fraction is then fabricated, and a test setup has been designed to measure its magnetic permeability. Using an advanced magnetorheometer, quasi-static tests are then carried out on MAE circular cylindrical samples to find their torque-twist response under various magnetic fields. The experimental results are then effectively utilized to identify the unknown parameters in the proposed material model. The accuracy of the proposed constitutive model in predicting the response behavior of the MAE is then demonstrated through comparison of theoretical results with those obtained experimentally.

Threshold Behavior of Volume Dust Cluster Untwisting in a Magnetic Field

The action of a magnetic field on the behavior of a bulk dust cluster formed in the strata of a glowing discharge has been studied. The cluster that consists of seven chains of particles and is a hexagonal cell in the horizontal cross-section has been studied. It has been found that the rotation of a dust cluster arises in nonzero magnetic field unlike the dusty structure containing many particles in the horizontal cross-section. Moreover, it has been found that the threshold behavior of the occurrence of rotation in the cluster is affected by the discharge current and plasma-forming gas pressure. The enhancement of the ionization inside a dust cluster is suggested as an interpretation. The radial ion flux that moves in the longitudinal magnetic field from the dusty structure to the discharge tube wall additionally twists the structure with the negative projection of an angular velocity on the magnetic induction vector.

Anisotropy of Isobaric Instability in a Partially Ionized Plasma in a Magnetic Field

Linear equations describing the dynamics of small perturbations in partially ionized heat-releasing plasma in an external magnetic field with an arbitrary induction vector are obtained. Using these equations, a dispersion relation for condensation modes is derived, and their time increments are calculated in the case of isobaric instability in the presence of anisotropy of the plasma thermal conductivity.

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.

MATHEMATICAL MODEL FOR SOLVING THE NAVIGATION PROBLEM AND ANGULAR ORIENTATION SPACECRAFT

Currently, there is an increased interest in the creation of strapdown inertial navigation systems (SINS), which make up the information core of modern airborne systems for the orientation and navigation of spacecraft (SC). An urgent problem arises, which is associated with the development of high-precision algorithms for estimating and filtering data from the sensors of the SC motion parameters, the mathematical model of the SINS, calculating its errors and analyzing the effect of errors on the characteristics of the navigation system and orientation of the SC. A mathematical model is proposed for solving the problem of navigation and angular orientation of a small SC equipped with electromagnetic control elements, taking into account the filtering of “noisy” magnetometer data. The requirements are set for the accuracy of the angular orientation and stabilization of the SC in the mode of maintaining the triaxial orientation of the SC in the orbital coordinate system (OCS) and for the duration of the damping mode of the angular velocities obtained by the SC during separation from the launch vehicle (LV), and the mode of the initial construction of the triaxial orientation of the SC in OCS. The mathematical model includes: a model of the motion of the center of mass of the SC in the osculating elements of the orbit with specified parameters, a model of the angular motion of the SC around the center of mass, a model of the Earth’s magnetic field (EMF) and a model of filtering magnetometer data. As an arithm for filtering data from a magnetometer on the components of the magnetic induction vector of the EMF, a one-parameter algorithm of exponential smoothing (exponential moving average) is used, which belongs to the class of first-order filters with an infinite impulse response. The results of numerical simulation of the dynamic processes of navigation and the angular orientation of the SC after separation from the LV taking into account the filtering of magnetometer data by the method of exponential smoothing using mathematical models are presented, and the accuracy of the angular orientation and stabilization of the SC is estimated.

Theoretical Analysis of Experimental Thermoelectric Characteristics of Silicon-Based Whiskers

It is shown that when a conductive crystal with electric field strength and a temperature gradient is placed in a magnetic field with an induction vector , processes of charge and heat carriers transport occur, and they can be described by known generalized electrical conduction and heat conduction equations. The tensors and scalar coefficients that make up these equations are the kinetic properties of crystals. They describe the nature of actual properties of crystals and have a wide pragmatic application in modern solid-state electronics. The process of spatial quantization of the spectrum and its influence on the kinetic properties of crystals is also analyzed.

Detecting BHP Flood Attacks in OBS Networks: A Machine Learning Prospective

The Optical Bust Switching (OBS) network has become the most promising switching technology for building the next generation of internet backbone infrastructure. However, an OBS network still faces a number of security and Quality of Service (QoS) challenges, particularly from Burst Header Packet (BHP) flood attacks. If a source node (ingress) becomes compromised by an attacker, overloading the network with malicious BHPs, the network resources will be reserved without proper utilization. This prevents legitimate BHPs from reserving the required resources, and can lead to severe issues, such as burst loss and Denial of Service (DoS) among others. One way to prevent a BHP flood attack is to detect the misbehaving edge nodes overloading the network with malicious BHPs, and taking the proper action to secure and sustain the QoS performance in an OBS network. A powerful and promising approach in identifying misbehaving edge nodes causing BHP flooding attacks is Machine Learning (ML), and in particular, classification techniques. A classification technique learns models by applying them to a large historical data set derived from an edge node’s performance during a simulation run. The data set contains behavior traces from a number of edge nodes, with respect to input data characteristics, sensitivity, efficiency performance, predictive performance, and model content. The learned model can then be utilized to single out (classify) misbehaving edge nodes based on their future performance as accurately as possible, hence disciplining them. In this paper, we investigate the BHP flood attack problem by evaluating a number of ML techniques in classifying edge nodes, and determine the most suitable method to prevent this type of attack. Specifically, we evaluate Decision Tree (C4.5), Bagging, Boosting (AdaBosst), Probabilistic (Naïve Bayes), Rule Induction (RIppleDOwn Rule Learner- RIDOR), Neural Network (NN-MultilayerPerceptron), Logistic Regression, and Support Vector Machine-Sequential Minimal Optimization (SVM-SMO) on a real dataset to identify the method(s) most appropriate to combat the BHP flood attack problem in OBS networks.

Accuracy assessment of microaccelerations simulation on the spacecraft “Foton-M” no. 2 according to magnetic measuring instruments data

The accuracy of modeling the field of microaccelerations of the internal environment of the middle class spacecraft of the Foton type is evaluated. It is assumed that the data of onboard magnetic measuring instruments were used as initial data for modeling micro-accelerations. The analyzed spacecraft do not have large elastic elements. The assessment was performed taking into account the influence of the work of the target and supporting equipment on the accuracy of measuring the components of the Earth’s magnetic field induction vector by airborne means. The presented assessment allows us to draw conclusions about the significance of the influence of the target and supporting equipment on a specific measuring instrument. It can be used in the design of promising technological spacecraft. With its help it is possible to analyze the accuracy of modeling the field of microaccelerations in the operating spacecraft provided that this simulation was based on data from onboard magnetic measuring instruments.

Computer modeling of HMCz Si growth

Abstract Czochralski growth of 300 mm diameter Si crystals with applied horizontal magnetic field is considered. A combined 2D-3D computer model is used for detailed description of thermal convection and oxygen transport in the melt. The model is extended to account for the effect of melt undercooling on the crystallization front and for the effect of soluto-capillary convection on the melt free surface. For a particular crystal growth system with published experimental data of temperature distribution in the melt, modeling results are compared with measurements and other calculations. A new flow structure in the melt is reported, which can explain experimental data with asymmetric melt temperature distribution around the crystal and with quite low temperature values in a small area under the free surface in the cross section orthogonal to the magnetic field induction vector. The effect of the melt flow on oxygen transport and different approaches of turbulence modeling are discussed as well.

An Unsaturated Inductance Reconstruction Based Universal Sensorless Starting Control Scheme for SRM Drives

In this article, an universal sensorless starting scheme considering magnetic saturation effects is proposed to control the switched reluctance motor (SRM) drives. In this approach, the full-cycle unsaturated inductance can be reconstructed by converting the saturated incremental inductance into the unsaturated inductance with a simple mathematical model in the conduction region. Based on the reconstructed three-phase full-cycle unsaturated inductance, the inductance vector coordinate transformation method and the linear region inductance model based method can be applied for estimating the rotor position even under high load starting case. To verify the validity of the proposed methods, experiments have been implemented in a 1-kW three-phase 12/8 structure SRM prototype. The experimental results verify that the unsaturated inductance reconstruction scheme can transfer the nonlinear magnetic saturation problem into an unsaturation problem, and thus the rotor position estimation at the sensorless starting state can be simplified. The method can realize the initial position estimation and reliable sensorless starting control even under load conditions with only very simple initial inductance data acquisition, position partition logics design, and mathematic modeling. In addition, as the back-electromotive force is eliminated indirectly in the inductance calculation process, the adaptable speed range can also be extended.

New look at an old principle: an alternative formulation of the theorem of minimum entropy production

We formulate a direct generalization of the Prigogine’s principle of minimum entropy production, according to a new isoperimetric variation principle by classical non-equilibrium thermodynamics. We focus our attention on the possible mathematical forms of constitutive equations. Our results show that the Onsager’s reciprocity relations are consequences of the suggested variation principle. Furthermore, we show by the example of the thermo-diffusion such reciprocity relations for diffusion tensor, which are missing in Onsager’s theory. Our theorem applied to the non-linear constitutive equations indicates the existence of dissipation potential. We study the forms of general reciprocity with the dissipation potential. This consideration results in a weaker condition than Li-Gyarmati-Rysselberhe reciprocity has. Furthermore, in the case of electric conductivity in the magnetic field, our theorem shows the correct dependence of the Onsager’s kinetic coefficient by the axial vector of magnetic induction. We show in general that the evolution criterion of the global entropy production is a Lyapunov-function, and so the final stationer state is independent of the initial, time-independent boundary conditions.

Dyonic solutions of Maxwell field equations in arbitrary media

In this paper, we report the reformulation of Maxwell equations for dyon in arbitrary media and it’s role in order to obtain the three set of solutions in terms of charge density $$\rho$$ , current density J, polarization P, and magnetization M. Present study determines the electric field E, electric displacement vector D, magnetic induction vector H, and magnetic field B as integrals of retarded charge density $$\rho$$ , current density J, polarization P and magnetization M, and their retarded spatial and temporal derivatives.