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Enhancing low-frequency induction heating effect of ferromagnetic composites : Toward medical applications

Abstract : Ferromagnetic composites, polymer matrix mixed with ferromagnetic particles show good potential in medical applications. In this thesis, we especially focus on the Low Frequency Induction Heating (LFIH) of ferromagnetic catheters as an alternative process for varicose veins ablation. The LFIH effect appears as soon as the composite is exposed to an alternating magnetic field. This phenomenon is mainly due to the so-called "microscopic" eddy currents generated by the magnetic domain wall motions. By inserting the catheter through a damaged varicose vein, and exciting it with a low frequency, high amplitude magnetic field, it is conceivable to reach a temperature high enough to properly heal the damaged area without injuring the surrounding healthy ones. Compared to the existing treatments, the LFIH method is accurate, cost competitive and simple. By transferring heat in a non-conductive way, the catheter bulkiness is reduced and the method is applicable even in tortuous veins. Ferromagnetic composites with different shapes and particle volume fractions were built and tested in a specific experimental bench. Different parameters (frequency, particle fraction …) were analyzed to reach the best thermal answer. The physical properties (permeability, electrical and thermal conductivities) were also characterized. A Comsol® model combining ferromagnetic behavior and thermal transfer properties was designed to improve the understanding of the phenomena. For a better efficiency, specimens with anisotropic magnetic behaviors were built by curing them under the influence of a static magnetic field. Finally, a commercial extrusion-type 3D printer was used to print samples with catheter shapes. Isotropic and anisotropic specimens were built. Interesting LFIH behavior were observed and for the later ones directional answers potentially interesting in alternative medical applications like the electromagnetic tracking (surgery navigation).
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Contributor : Abes Star :  Contact
Submitted on : Thursday, May 20, 2021 - 3:36:08 PM
Last modification on : Monday, November 29, 2021 - 11:12:02 AM
Long-term archiving on: : Saturday, August 21, 2021 - 6:49:05 PM


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  • HAL Id : tel-03231248, version 1


Ziyin Xiang. Enhancing low-frequency induction heating effect of ferromagnetic composites : Toward medical applications. Materials. Université de Lyon, 2021. English. ⟨NNT : 2021LYSEI022⟩. ⟨tel-03231248⟩



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