Specific loss power in superparamagnetic hyperthermia: nanofluid versus composite

Currently, the magnetic hyperthermia induced by nanoparticles is of great interest in biomedical applications. In the literature, we can find a lot of models for magnetic hyperthermia, but many of them do not give importance to a significant detail, such as the geometry of nanoparticle positions in the system. Usually, a nanofluid is treated by considering random positions of the nanoparticles, geometry that is actually characteristic to the composite nanoparticles. To assess the error which is frequently made, in this paper we propose a comparative analysis between the specific loss power (SLP) in case of a nanofluid and the SLP in case of a composite with magnetic nanoparticles. We are going to use a superparamagnetic hyperthermia model based on the improved model for calculating the Neel relaxation time in a magnetic field oblique to the nanoparticle magnetic anisotropy axes, and on the improved theoretical model LRT (linear response theory) for SLP. To generate the nanoparticle geometry in the system, we are going to apply a Monte Carlo method to a nanofluid, by minimising the interaction potentials in liquid medium and, for a composite environment, a method for generating random positions of the nanoparticles in a given volume

The Néel magnetic relaxation dynamics in nanoparticle systems - phenomenological approach versus stochastic approach

In nanomagnetism, the studies of magnetic nanoparticle systems are of particular interest from both experimental and theoretical points of view. Experimentally, the measurements made on such a system are hard to interpret. It is very difficult to distinguish the effect of the magnetic dipole interactions from the effects of size distribution or effective magnetic anisotropy constants. In this respect, the simulation models can help. This paper presents a study comparing the two conventional approaches, using simulation models for the magnetic relaxation dynamics of nanoparticle systems, i.e. a phenomenological Ising-type approach, on two levels, and a stochastic approach. The paper also shows a way of using these approaches in creating a model to simulate the Néel magnetic relaxation time for aligned magnetic nanoparticle systems

Relaxation Times in Magnetic Nanoparticles System and Memory Effects

Some memory effects in nanoparticle systems, similar to those seen in spin glass systems, may have important device applications, by tuning the interaction and the particle size. Recently, this subject provoked a special interest in nano-sciences. In this work we present a study, by simulation of the mode in which the behavior of a magnetic nanoparticle system is influenced by the superposition of the dimensions' distribution, the effective anisotropy constants and the disposal of nanoparticles in the sample, if we take into account the dipolar magnetic interaction

Relaxation Times in Magnetic Nanoparticles System and Memory Effects

Some memory effects in nanoparticle systems, similar to those seen in spin glass systems, may have important device applications, by tuning the interaction and the particle size. Recently, this subject provoked a special interest in nano-sciences. In this work we present a study, by simulation of the mode in which the behavior of a magnetic nanoparticle system is influenced by the superposition of the dimensions' distribution, the effective anisotropy constants and the disposal of nanoparticles in the sample, if we take into account the dipolar magnetic interaction

About the Possibility of Power Controlling in the Three-Phase Electric Arc Furnaces Using PSCAD EMTDC Simulation Program

The electric arc is a nonlinear element. For this reason it must be used special techniques of modeling the electric arc that should reflect as closely as possible the behavior of the real electric arc. In this paper, the modeling of the functioning of the electrical installation of the electric arc furnace was done using the PSCAD-EMTDC simulation program. The electric arc furnaces do not absorb sinusoidal currents and generally consume reactive power. These two phenomena produce some disturbances like the dysfunction of the equipment in the worst cases. It is perform a study of the possibilities of controlling the electric arc power, in order to obtained maximum of the active power and reducing the reactive and distorted power