Next Article in Journal
Fe-Doped Sol-Gel Glasses and Glass-Ceramics for Magnetic Hyperthermia
Next Article in Special Issue
Structure and Electromagnetic Properties of Cellular Glassy Carbon Monoliths with Controlled Cell Size
Previous Article in Journal
One-Step Preparation of Large Area Films of Oriented MoS2 Nanoparticles on Multilayer Graphene and Its Electrocatalytic Activity for Hydrogen Evolution
Article Menu
Issue 1 (January) cover image

Export Article

Open AccessArticle
Materials 2018, 11(1), 169; https://doi.org/10.3390/ma11010169

Effect of Aspect Ratio on the Permittivity of Graphite Fiber in Microwave Heating

1
Department of Applied Chemistry, Tohoku University, 6-6 Aoba, Aramaki, Aoba, Miyagi 980-8579, Japan
2
Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Ōokayama 2-12-1, Meguro, Tokyo 152-8552, Japan
3
Faculty of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
4
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
5
Department of Mechanical Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
6
National Institute of Technology, Okinawa College, 905 Henoko, Nago-city, Okinawa 903-0213, Japan
*
Author to whom correspondence should be addressed.
Received: 21 November 2017 / Revised: 11 January 2018 / Accepted: 17 January 2018 / Published: 22 January 2018
(This article belongs to the Special Issue Electromagnetic Wave Absorbing Structures)
View Full-Text   |   Download PDF [3083 KB, uploaded 22 January 2018]   |  

Abstract

Microwave (MW) heating has received attention as a new heating source for various industrial processes. Some materials are expected to be a more effective absorber of MW, and graphite is observed as a possible candidate for high-temperature application. We investigated the dependence of the aspect ratio of graphite fibers on both their heating behavior and permittivity under a 2.45 GHz MW electric field. In these experiments, both loss tangent and MW heating behavior indicated that the MW absorption of conductive fibers increases with their aspect ratio. The MW absorption was found to be well accounted for by the application of a spheroidal model for a single fiber. The absorption of graphite fibers decreases with increasing aspect ratio when the long axis of the ellipsoid is perpendicular to the electric field, whereas it increases with the aspect ratio when the long axis is parallel to the electric field. The analytical model indicated that MW heating of the conductive fibers is expected to depend on both the shape and arrangement of the fibers in the electric field. View Full-Text
Keywords: microwave heating; electrical permittivity; graphite; shape effect microwave heating; electrical permittivity; graphite; shape effect
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

  • Externally hosted supplementary file 1
    Doi: 249650
SciFeed

Share & Cite This Article

MDPI and ACS Style

Fukushima, J.; Tsubaki, S.; Matsuzawa, T.; Kashimura, K.; Mitani, T.; Namioka, T.; Fujii, S.; Shinohara, N.; Takizawa, H.; Wada, Y. Effect of Aspect Ratio on the Permittivity of Graphite Fiber in Microwave Heating. Materials 2018, 11, 169.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top