Abstract: Recently, bianisotropic media again received
increasing importance in electromagnetic theory because of advances
in material science which enable the manufacturing of complex
bianisotropic materials. By using Maxwell's equations and
corresponding boundary conditions, the electromagnetic field
distribution in bianisotropic solenoid coils is determined and the
influence of the bianisotropic behaviour of coil to the impedance and
Q-factor is considered. Bianisotropic media are the largest class of
linear media which is able to describe the macroscopic material
properties of artificial dielectrics, artificial magnetics, artificial chiral
materials, left-handed materials, metamaterials, and other composite
materials. Several special cases of coils, filled with complex
substance, have been analyzed. Results obtained by using the
analytical approach are compared with values calculated by
numerical methods, especially by our new hybrid EEM/BEM method
and FEM.
Abstract: This work focuses on analysis of classical heat transfer equation regularized with Maxwell-Cattaneo transfer law. Computer simulations are performed in MATLAB environment. Numerical experiments are first developed on classical Fourier equation, then Maxwell-Cattaneo law is considered. Corresponding equation is regularized with a balancing diffusion term to stabilize discretizing scheme with adjusted time and space numerical steps. Several cases including a convective term in model equations are discussed, and results are given. It is shown that limiting conditions on regularizing parameters have to be satisfied in convective case for Maxwell-Cattaneo regularization to give physically acceptable solutions. In all valid cases, uniform convergence to solution of initial heat equation with Fourier law is observed, even in nonlinear case.
Abstract: The optimal control problem for the viscoelastic melt
spinning process has not been reported yet in the literature. In this
study, an optimal control problem for a mathematical model of a
viscoelastic melt spinning process is considered. Maxwell-Oldroyd
model is used to describe the rheology of the polymeric material, the
fiber is made of. The extrusion velocity of the polymer at the spinneret
as well as the velocity and the temperature of the quench air and the
fiber length serve as control variables. A constrained optimization
problem is derived and the first–order optimality system is set up
to obtain the adjoint equations. Numerical solutions are carried out
using a steepest descent algorithm. A computer program in MATLAB
is developed for simulations.
Abstract: The stability of Newtonian and Non-Newtonian extending films under local or global heating or cooling conditions are considered. The thickness-averaged mass, momentum and energy equations with convective and radiative heat transfer are derived, both for Newtonian and non-Newtonian fluids (Maxwell, PTT and Giesekus models considered). The stability of the system is explored using either eigenvalue analysis or transient simulations. The results showed that the influence of heating and cooling on stability strongly depends on the magnitude of the Peclet number. Examples of stabilization or destabilization of heating or cooling are shown for Pe
Abstract: An innovative tri-axes micro-power receiver is
proposed. The tri-axes micro-power receiver consists of two sets 3-D
micro-solenoids and one set planar micro-coils in which iron core is
embedded. The three sets of micro-coils are designed to be orthogonal
to each other. Therefore, no matter which direction the flux is present
along, the magnetic energy can be harvested and transformed into
electric power. Not only dead space of receiving power is mostly
reduced, but also transformation efficiency of electromagnetic energy
to electric power can be efficiently raised. By employing commercial
software, Ansoft Maxwell, the preliminary simulation results verify
that the proposed micro-power receiver can efficiently pick up the
energy transmitted by magnetic power source.
As to the fabrication process, the isotropic etching technique is
employed to micro-machine the inverse-trapezoid fillister so that the
copper wire can be successfully electroplated. The adhesion between
micro-coils and fillister is much enhanced.
Abstract: This paper presents the study of induced currents and
temperature distribution in gear heated by induction process using 2D
finite element (FE) model. The model is developed by coupling
Maxwell and heat transfer equations into a multi-physics model. The
obtained results allow comparing the medium frequency (MF) and
high frequency (HF) cases and the effect of machine parameters on
the evolution of induced currents and temperature during heating.
The sensitivity study of the temperature profile is conducted and the
case hardness is predicted using the final temperature profile. These
results are validated using tests and give a good understanding of
phenomena during heating process.
Abstract: The present work deals with the calculation of
transport properties of Hg0.8Cd0.2Te (MCT) semiconductor in
degenerate case. Due to their energy-band structure, this material
becomes degenerate at moderate doping densities, which are around
1015 cm-3, so that the usual Maxwell-Boltzmann approximation is
inaccurate in the determination of transport parameters. This problem
is faced by using Fermi-Dirac (F-D) statistics, and the non-parabolic
behavior of the bands may be approximated by the Kane model. The
Monte Carlo (MC) simulation is used here to determinate transport
parameters: drift velocity, mean energy and drift mobility versus
electric field and the doped densities. The obtained results are in
good agreement with those extracted from literature.