Modeling a New Design for Heat Transfer System and Electrical Generator

Traditional heat transfer techniques have become inadequate for many applications today and innovation of new technologies has become an urgent necessity. From another angle, securing electrical power remote areas in unconventional ways is receiving widespread attention. In this study, we present a new technique to dissipate heat, which is suitable in narrow and slanted places, as well as, generate electricity. The system consists of a permanent magnet (PM) and a spring where they act as opposing forces on a ferromagnetic disk moving in a specific space. Above the Curie temperature (Tc) of the ferromagnet, spring force (Fspring) overcomes the strength of the PM due to loss the magnetic susceptibility of the ferromagnet. PM’s force is gradually increasing and overcomes the Fspring due to the cooling of the ferromagnetic. Thermally, the system consists of high and low temperature zones and the ferromagnetic works as an active heat carrier. The opposing forces of the PM and the spring make the ferromagnetic moves in two opposite directions. COMSOL Multiphysics 5.2a software is used to get the simulation results in this study. This technique is suitable for many applications especially when heat transfer is required in the horizontal or oblique direction. This technique provides clean energy using only a waste heat from anywhere as a source.

Spin-transfer torque in nonuniform magnetic structures

This chapter defines a magnetic domain wall (DW) as the transition region where the direction of magnetic moments gradually change between two neighbouring domains. It has been pointed out that ferromagnetic materials are not necessarily magnetized to saturation in the absence of an external magnetic field. Instead, they have magnetic domains, within each of which magnetic moments align. The formation of the magnetic domains is energetically favourable because this structure can lower the magnetostatic energy originating from the dipole–dipole interaction. A magnetic vortex realized in a ferromagnetic disk is a typical example of nonuniform magnetic structure. In very small ferromagnetic systems, where a curling spin configuration has been proposed to occur in place of domains, the formation of DWs is not energetically favored.