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Characteristics of radio-frequency/vacuum combined with mechanical press drying of heavy softwood timbers with longitudinal kerf

Xuefeng Zhao and Changjin Lee
From the journal Holzforschung

Abstract

The aim of this study was to evaluate the characteristics of radio-frequency/vacuum combined with mechanical press (RF/VP) drying on three softwood timbers (Douglas fir, Hemlock, and Radiata pine) with longitudinal kerfs. The results were as follows: Due to the dielectric permittivity of wood, RF/VP drying at a fixed frequency of 13.56 MHz significantly influenced the moisture content (MC) distribution, the number of surface checks, shrinkage, and warp. These observations were attributed to the formation of a temperature gradient along the charge plate during the drying. The presence or absence of pith, more affected an occurrence of surface checks than that of the stresses within the wood during drying. The longitudinal kerf reduced the number of surface checks, but did not affect the MC distribution or the twist after drying.


Corresponding author: Changjin Lee, Department of Wood Science and Technology, College of Agriculture and Life Sciences, Jeonbuk National University, Jeonju 54896, Korea, E-mail:

Funding source: Business for Cooperative R&D between Industry, Academy, and Research Institute Korea Small and Medium Business Administration

Award Identifier / Grant number: C0103823

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: This work was supported by Business for Cooperative R&D between Industry, Academy, and Research Institute Korea Small and Medium Business Administration (no. C0103823).

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.

  5. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

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Received: 2019-10-23
Accepted: 2020-04-07
Published Online: 2020-06-24
Published in Print: 2021-01-26

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