Special Issue "Advances in Computational Electromagnetics"

A special issue of Magnetochemistry (ISSN 2312-7481).

Deadline for manuscript submissions: closed (30 December 2020).

Special Issue Editor

Dr. Valerio De Santis
E-Mail Website
Guest Editor
DIIIE, University of L’Aquila, L'Aquila, Italy
Interests: computational electromagnetics; numerical dosimetry; biological effects of electromagnetic fields; EMF compliance of emerging technologies and medical devices
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Complex magnetic materials, such as superconducting materials, composite or nanomaterials, rare-earth free permanent magnets and so on are becoming more and more popular in next-generation technologies. The experimental characterization of these materials is often too costly or even not applicable, while fast and efficient computational electromagnetic (CEM) methods are currently available to understand and fully characterize the behavior of such materials.

This Special Issue of Magnetochemistry aims at publishing a collection of research contributions illustrating the recent advances in computational electromagnetic techniques needed to model and characterize complex magnetic materials, namely in the topics listed below.

Dr. Valerio De Santis
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Magnetochemistry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Computational methods for electromagnetics
  • Numerical techniques for solving static and quasi-static fields
  • Material modeling
  • Nanomagnetics modeling
  • Nano-electromagnetic computation
  • Bio-electromagnetic computation
  • Multiscale modeling and homogenization
  • Electromagnetic inverse problems
  • Optimization and design of electromagnetic devices
  • Novel computational methods for machines and devices

Published Papers (8 papers)

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Editorial

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Editorial
Special Issue: Advances in Computational Electromagnetics
Magnetochemistry 2021, 7(6), 89; https://doi.org/10.3390/magnetochemistry7060089 - 21 Jun 2021
Viewed by 385
Abstract
Recent advances in computational electromagnetics (CEMs) have made the full characterization of complex magnetic materials possible, such as superconducting materials, composite or nanomaterials, rare-earth free permanent magnets, etc [...] Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)

Research

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Article
Oscillatory Copper Deposition on Conical Iron Electrodes in a Nonuniform Magnetic Field
Magnetochemistry 2021, 7(4), 46; https://doi.org/10.3390/magnetochemistry7040046 - 28 Mar 2021
Cited by 1 | Viewed by 659
Abstract
We report the effect of a magnetic field on the deposition of copper ions on a conically shaped iron probe. In our setup, the magnetic forces and buoyancy are the key factors influencing the electrolyte flow and the mass transfer. Without external current, [...] Read more.
We report the effect of a magnetic field on the deposition of copper ions on a conically shaped iron probe. In our setup, the magnetic forces and buoyancy are the key factors influencing the electrolyte flow and the mass transfer. Without external current, a spontaneous reduction of copper on the iron cone occurs, known as electroless deposition. Mach–Zehnder and differential interferometry indicate a variation in the concentration of copper ions near the cone. After an initial transient of about 60 s, temporal oscillations in the copper concentration are found under the effect of a magnetic field. In galvanostatic conditions, a similar oscillatory behavior of the concentration of the electrolyte is observed. Numerical simulations show that the oscillations are caused by the magnetic gradient, Lorentz force, and buoyancy force counteracting one another, and the oscillation frequency is estimated analytically based on this mechanism. Furthermore, we present a study on the oscillation frequency for both electroless and galvanostatic conditions with different current densities. The results of this study may stimulate future research aimed at the local control of the deposition rate and the realization of miniaturized, regularly structured deposits using magnetic fields. Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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Article
Numerical Computation and Analysis of Electromagnetic Field in Magnetic Suspension and Balance System
Magnetochemistry 2021, 7(3), 33; https://doi.org/10.3390/magnetochemistry7030033 - 26 Feb 2021
Cited by 1 | Viewed by 676
Abstract
The magnetic suspension wind tunnel balance (MSBS) is an entirely new device for aerodynamic measurement, and it makes the best of the electromagnetic force to suspend the aircraft model in the wind tunnel without contact. Compared with conventional wind tunnel balance, it absolutely [...] Read more.
The magnetic suspension wind tunnel balance (MSBS) is an entirely new device for aerodynamic measurement, and it makes the best of the electromagnetic force to suspend the aircraft model in the wind tunnel without contact. Compared with conventional wind tunnel balance, it absolutely abandons the model support and airflow interference. Therefore, the aerodynamic measurement environment is more authentic and the aerodynamic measurement results are more accurate. The electromagnetic field in MSBS plays a major role in bearing the force of wind. The numerical computation and finite element numerical analysis are performed to investigate key factors of electromagnetic force under different conditions. The calculation results based on finite element method (FEM) have revealed that the diameter and the spacing of of the axial coil, the number of segments and the pitch angle of the suspension model are key factors of electromagnetic force. Based on the above key factors, the structure of the magnetic suspension balance is optimized to maximize the electromagnetic force under multiple constraints. Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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Article
Chassis Influence on the Exposure Assessment of a Compact EV during WPT Recharging Operations
Magnetochemistry 2021, 7(2), 25; https://doi.org/10.3390/magnetochemistry7020025 - 07 Feb 2021
Cited by 2 | Viewed by 570
Abstract
In this study, the external magnetic field emitted by a wireless power transfer (WPT) system and the internal electric field induced in human body models during recharging operations of a compact electric vehicle (EV) are evaluated. The magneticfield is calculated with a hybrid [...] Read more.
In this study, the external magnetic field emitted by a wireless power transfer (WPT) system and the internal electric field induced in human body models during recharging operations of a compact electric vehicle (EV) are evaluated. The magneticfield is calculated with a hybrid scheme coupling the boundary element method with the surface impedance boundary conditions in order to fit the multiscale open-boundary characteristics of the problem. A commercial software is then used to perform numerical dosimetry. Specifically, two realistic anatomical models, both in a driving position and in a standing posture, are considered, and the chassis of the EV is modeled either as a currently employed aluminum alloy and as a futuristic carbon fiber composite panel. Aligned and misaligned coil configurations of the WPT system are considered as well. The analysis of the obtained results shows that the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels are exceeded in the driving position, especially for the carbon fiber chassis, whereas the system is compliant with the basic restrictions, at least for the considered scenarios. Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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Article
Identification of Material Properties and Optimal Design of Magnetically Shielded Rooms
Magnetochemistry 2021, 7(2), 23; https://doi.org/10.3390/magnetochemistry7020023 - 06 Feb 2021
Cited by 1 | Viewed by 863
Abstract
In this paper, we propose an optimal design procedure for magnetically shielded rooms. Focusing on multi-layer ferromagnetic structures, where inner layers operate at very low magnetic field, we propose an identification method of the magnetic material characteristic in the Rayleigh region. A numerical [...] Read more.
In this paper, we propose an optimal design procedure for magnetically shielded rooms. Focusing on multi-layer ferromagnetic structures, where inner layers operate at very low magnetic field, we propose an identification method of the magnetic material characteristic in the Rayleigh region. A numerical model to simulate the shielding efficiency of a multi-layer ferromagnetic structure is presented and experimentally tested on different geometries and layer configurations. The fixed point iterative method is adopted to handle the nonlinearity of the magnetic material. In conclusion, the optimization of the design parameters of a MSR is discussed, using the Vector Immune System algorithm to minimize the magnetic field inside the room and the cost of the structure. The results highlight that a linear magnetic characteristic for the material is sufficient to identify the suitable geometry of the shield, but the nonlinear model in the Rayleigh region is of fundamental importance to determine a realistic shielding factor. Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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Article
Vector Hysteresis Processes for Innovative Fe-Si Magnetic Powder Cores: Experiments and Neural Network Modeling
Magnetochemistry 2021, 7(2), 18; https://doi.org/10.3390/magnetochemistry7020018 - 24 Jan 2021
Cited by 2 | Viewed by 552
Abstract
A thorough investigation of the 2-D hysteresis processes under arbitrary excitations was carried out for a specimen of innovative Fe-Si magnetic powder material. The vector experimental measurements were first performed via a single disk tester (SDT) apparatus under a controlled magnetic induction field, [...] Read more.
A thorough investigation of the 2-D hysteresis processes under arbitrary excitations was carried out for a specimen of innovative Fe-Si magnetic powder material. The vector experimental measurements were first performed via a single disk tester (SDT) apparatus under a controlled magnetic induction field, taking into account circular, elliptic, and scalar processes. The experimental data relative to the circular loops were utilized to identify a vector model of hysteresis based on feedforward neural networks (NNs), having as an input the magnetic induction vector B and as an output the magnetic field vector H. Then the model was validated by the simulation of the other experimental hysteresis processes. The comparison between calculated and measured loops evidenced the capability of the model in both the reconstruction of the magnetic field trajectory and the prediction of the power loss under various excitation waveforms. Finally, the computational efficiency of the model makes it suitable for future application in finite element analysis (FEA). Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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Article
A Novel Computational Method to Identify/Analyze Hysteresis Loops of Hard Magnetic Materials
Magnetochemistry 2021, 7(1), 10; https://doi.org/10.3390/magnetochemistry7010010 - 07 Jan 2021
Cited by 1 | Viewed by 980
Abstract
In this study, a novel computational method capable of reproducing hysteresis loops of hard magnetic materials is proposed. It is conceptually based on the classical Preisach model but has a completely different approach in the modeling of the hysteron effect. Indeed, the change [...] Read more.
In this study, a novel computational method capable of reproducing hysteresis loops of hard magnetic materials is proposed. It is conceptually based on the classical Preisach model but has a completely different approach in the modeling of the hysteron effect. Indeed, the change in magnetization caused by a single hysteron is compared here to the change in velocity of two disk-shaped solids elastically colliding with each other rather than the effect of ideal geometrical entities giving rise to so-called Barkhausen jumps. This allowed us to obtain a simple differential formulation for the global magnetization equation with a significant improvement in terms of computational performance. A sensitivity analysis on the parameters of the proposed method has indeed shown the capability to model a large class of hysteresis loops. Moreover, the proposed method permits modeling of the temperature effect on magnetization of neodymium magnets, which is a key point for the design of electrical machines. Therefore, application of the proposed method to the hysteresis loop of a real NdFeB magnet has been proven to be very accurate and efficient for a large temperature range. Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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Article
The Microstructural Model of the Ferromagnetic Material Behavior in an External Magnetic Field
Magnetochemistry 2021, 7(1), 7; https://doi.org/10.3390/magnetochemistry7010007 - 01 Jan 2021
Cited by 3 | Viewed by 887
Abstract
In this paper, the behavior of a ferromagnetic material is considered in the framework of microstructural modeling. The equations describing the behavior of such material in the magnetic field, are constructed based on minimization of total magnetic energy with account of limitations imposed [...] Read more.
In this paper, the behavior of a ferromagnetic material is considered in the framework of microstructural modeling. The equations describing the behavior of such material in the magnetic field, are constructed based on minimization of total magnetic energy with account of limitations imposed on the spontaneous magnetization vector and scalar magnetic potential. This conditional extremum problem is reduced to the unconditional extremum problem using the Lagrange multiplier. A variational (weak) formulation is written down and linearization of the obtained equations is carried out. Based on the derived relations a solution of a two-dimensional problem of magnetization of a unit cell (a grain of a polycrystal or a single crystal of a ferromagnetic material) is developed using the finite element method. The appearance of domain walls is demonstrated, their thickness is determined, and the history of their movement and collision is described. The graphs of distributions of the magnetization vector in domains and in domain walls in the external magnetic field directed at different angles to the anisotropy axis are constructed and the magnetization curves for a macrospecimen are plotted. The results obtained in the present paper (the thickness of the domain wall, the formation of a 360-degree wall) are in agreement with the ones available in the current literature. Full article
(This article belongs to the Special Issue Advances in Computational Electromagnetics)
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