Dielectric properties of bark of Japanese cedar with high moisture content
2019
Miyoshi, Y. (Forestry and Forest Products Research Institute (Japan)) | Suzuki, Y.
In this study, the relationship between moisture content and the dielectric constant ε' of the bark of Japanese cedar (Cryptomeria japonica) was investigated. Specimens of the xylem, inner bark, outer bark and inner bark, and from outer bark to xylem, with high moisture contents were measured during drying under a frequency of 20 Hz - 2 MHz at 20℃. The ε' of the specimen with outer bark was higher than that of the xylem specimen when moisture content was above 180%. The ε' of the inner bark specimen was lower than that of the xylem specimen when moisture content was above 180%. The inner bark specimen has a large amount of resin, which was extracted using methanol. The ε' of the inner bark specimen after resin extraction increased when moisture content was above 50%. This indicates the dielectric properties of the bark are different from those of the xylem, and the ε' of the inner bark is low because of its resin composition.
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