Mathematical Models and Numerical Simulation in Electromagnetism

Abstract

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3D models of proximity effects in large FeSi and FeMn furnaces

“…Hence, the electric field E(r,t) (V/m), which generally depends on time and space, can be written E(r,t) = Re(e i t E(r)), where Re denotes the real part of its argument, E(r) is the time-independent complex amplitude, and = 2 f. In the following, all electromagnetic fields are denoted in terms of their complex amplitude fields. The electromagnetic fields inside the furnace are accurately described by the low-frequency approximation of the time-harmonic Maxwell's equations (Bermúdez, Gómez, and Salgado, 2014;Rodríguez and Valli, 2010):…”

“…, one finds that the electromagnetic fields and currents decay inside conductors, such that the currents effectively accumulate on the surface of the conductor (Bermúdez, Gómez, and Salgado, 2014;Ramo, Whinnery, and van Duzer, 1994), i.e., the so-called skin effect, which is particularly evident at higher frequencies and for thicker conductors of high electrical conductivity or relative magnetic permeability. To exhibit an appreciable skin effect, the conductor must be large enough to accommodate significant amounts of self-induced eddy currents.…”

Lowest order Virtual Element approximation of magnetostatic problems

“…Figs. 8 and 9 show a qualitative comparison between the solution provided in [13] (left), and that obtained by the present method (right). More specifically, in Fig.…”

“…In this subsection we consider a typical benchmark problem, see e.g. [13,14,20]. The geometry consists in a ferromagnetic cylindrical core, C, surrounded by a toroidal coil with a rectangular cross section, T , with air, A, around these two structures.…”

Innovative Theoretical Approaches Used for RF Power Amplifiers in Modern HDTV Systems

“…This means expensive and specialized setups capable of performing the necessary measurements [36][37][38][39][40][41][42][43][44][45]. In Section 5, we present a high performance and low-cost setup designed for test and characterization of RF high-power amplifiers, capable of generate reports that will help the operator to decide about the conformity of the equipment with other ones tested, as we can see in the characterization of a power drawer [46][47][48][49][50][51][52].…”