Paper presents utilized innovative setup for eddy current tomography and possibility of its utilization in testing oxide materials such as ferrites. Previously reported tests concerned materials with high conductivity which is the most typical usage of eddy current tests. Described tomography setup is designed for testing axisymmetric objects thus typical ferrite ring was selected for exemplary testing. Tests were conducted on ring in original state. Afterwards reference defect was created on element and measurements were repeated. Significant difference between tests results were observed, thus potential for utilization in controlling of ferrite rings manufacturing process was confirmed. Finite element method simulations were applied in order to confirm the measurement results. Calculations were conducted in open-source finite element method software, which solves the Maxwell equations in the A-V form. Modelling results confirm possibility of finite element method-based inverse tomography transformation.
Paper presents utilized innovative setup for eddy current tomography and possibility of its utilization in automotive industry. Described tomography setup is designed for testing axisymmetric objects thus motor valve was selected for exemplary testing. Tests were conducted on motor valve in original state. Afterwards reference defect was created on element and measurements were repeated. Significant difference between tests results were observed, thus potential for utilization in automotive industry was confirmed. Finite element method simulations were applied in order to confirm the measurement results. Calculations were conducted in open-source finite element method software, which solves Maxwell equations in the A-V form. Modelling results confirm possibility of finite element method-based inverse tomography transformation.
A new version of the construction of the extraordinary magnetoresistance effect (EMR) based magnetic sensor has been proposed [2]. The differences between the original three dimensional (3D) construction and proposed 2D (planar) construction are presented. In proposed construction the metallic thin film (shunt) is coplanar with the semiconductor sensitive element. There are advantages of that planar construction like easier way of technological obtaining of the device. Another advantage is its application for EMR sensors based on new electronic materials like graphene and topological insulator thin films. The validity of the planar construction has been experimentally confirmed for model EMR sensors based on InSb/Ag structures. Comparison of the obtained experimental data with computational simulations of the EMR effect on planar model EMR sensors is performed Finite element method (FEM) is used as a tool for obtaining EMR effect simulations.
Bi₅Ti₃FeO₁₅ ceramics belongs to multiferroic class of materials. In this work it was prepared by solid-state sintering method and investigated by X-ray diffraction, Mössbauer spectroscopy, and magnetoelectric effect measurements. As it was proved by X-ray diffraction studies the single-phase Bi₅Ti₃FeO₁₅ compound was obtained. The Mössbauer investigations revealed paramagnetic character of the compound at room temperature as well as at 80 K. Magnetoelectric measurements were carried out at room temperature using lock-in dynamic method and they proved presence of magnetoelectric coupling in this material. Additional magnetoelectric studies were carried out after subsequent electric poling of the sample. It was found that the maximum value of the coupling coefficient was almost twice bigger than in the case without the initial poling and reached a value of α_{ME} ≈ 20.7 mV cm⁻¹ Oe⁻¹.
The present research intends to establish a numerical model, on the basis of a theoretical analysis, for describing and analyzing the electric field of High Voltage Direct Current (HVDC) wall bushing that demonstrates highly nonlinear characteristics. The wall bushing is subjected high voltage with nonlinear electric field and the relationship between the electric field intensity and the resistance of the insulators of the wall bushing is highly nonlinear. With a parameter design language of a Finite Element Analysis software package for carrying out the numerical calculations, the effects of the nonlinearity on the electric field can be well taken into consideration in performing the numerical assessment. A technique utilizing the numerical iteration is developed for quantifying the electric intensity of the electric field. With the model and the iteration technique established, the nonlinear characteristics of the HVDC wall bushing can be investigated with efficiency.
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