This article presents experimental and computational results of electroporation in rat liver. The experiments were performed using different forms of electrodes and waveforms of applied electric pulses. For the numerical simulation, the electroporation model proposed by Ramos and Weinert in a previous publication was used. Dynamic adjustments were used for obtaining a good modeling of the electric current. A single set of model parameters was obtained to fit the simulated current response for different waveforms and electrodes. These parameters were obtained with the use of a genetic algorithm that minimized the error between the simulated and experimental currents. The electroporation model with dynamic adjustment proved to be an appropriate simulation tool to predict the tissue conductivity during stimulation by intense electrical fields.
The paper describes an approach to teaching mutually-coupled circuits CAD techniques to undergraduate students pursuing a degree course in electrical engineering or physics, and explains how a series of simulated experiments may be incorporated into the existing subjects. The simulated experiments make use of a two-dimensional open-access software based on the finite-element method. At the laboratory meetings, the students learn how to set up field problems for solution, and how to examine the results. Simulation tasks based on three axisymmetric open-boundary problems are used to introduce different numeric techniques to compute inductance and magnetic forces. The paper takes the reader to a step-by-step simulation journey, and provides all the basic elements required for further exploration of axially-symmetric systems.
The paper describes an approach to teaching low-frequency electromagnetic CAD techniques to undergraduate students pursuing a degree course in electrical engineering. The simulated experiments make use of a two-dimensional open-access software based on the finite-element method. At the laboratory meetings, the problems are initially solved analytically. Upon this, students learn how to create the numeric model and how to define the sequence of field problems that lead to the required solution. Simulation tasks based on a force-producing electromagnet are used to introduce numeric techniques to determine magnetic field distribution, evaluation of energy storage and generation of magnetic forces. The nature of the magnetic force generated in the air gaps of the C-core electromagnet is explained in detail. Magnetic forces are calculated by the classical and weighted versions of the method of Maxwell stress tensor. The paper provides all the basic elements required for further exploration of devices with longitudinal symmetry. Journal of Electromagnetic Analysis and Applications involving non-homogeneous, non-linear and time-dependent problems has been determinant in the choice of this numerical method. The manuscript takes the reader to a step-by-step simulation journey that provides all the basic elements required for the analysis of electromagnetic devices with longitudinal symmetry.A. F. L. Nogueira et al.
Resumo -Este artigo apresenta um circuito Gerador de Marx (GM) bipolar, capaz de gerar pulsos com parâmetros elétricos destinados à eletropermeabilização biológica. Este procedimento consiste em aplicar campos elétricos intensos em tecidos vivos para a criação de poros em suas membranas celulares, e com isso otimizar procedimentos como introdução de medicamentos, transferência genética, fusão molecular e até acelerar a morte de um conjunto celular. É desenvolvido um GM bipolar capaz de obter tensão pulsada de 1200 V a partir de uma entrada em 300 V. O multiplicador de tensão se baseia em um sistema com capacitores conectados ora em paralelo e ora em série. Testes práticos foram realizados com uma amostra vegetal, a fim de analisar o funcionamento do gerador, explorando os múltiplos parâmetros ajustáveis proporcionados pelos circuitos.
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