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Characteristics of the Radio-Frequency/Vacuum Drying of Heavy Timbers for Post and Beam of Korean Style Housings Part II: For Korean Red Pine Heavy Timbers with 250 × 250 mm, 300 × 300 mm in Cross Section and 300 mm in Diameter, and 3,600 mm in Length

https://research.thinkwood.com/en/permalink/catalogue1508
Year of Publication
2011
Topic
Moisture
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Author
Lee, Nam-Ho
Zhao, Xue-Feng
Shin, Ik-Hyun
Park, Moon-Jae
Park, Jung-Hwan
Park, Joo-Saeng
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2011
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Topic
Moisture
Keywords
Radio-Frequency/Vacuum Drying
Moisture Gradient
Shrinkage
Case Hardening
Surface Checks
Compressive Load
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
This study examined the characteristics of radio-frequency/vacuum dried Korean red pine (Pinus densoflora heavy timbers with 250 × 250 mm (S), 300 × 300 mm (L) in cross section and 300 mm in diameter, and 3,600 mm in length, which were subjected to compressive loading after a kerf pretreatment. The following results were obtained : The drying time was short and the drying rate was high in spite of the large cross section of specimens. The moisture gradient inall specimens was gentle in both longitudinal and transverse directions owing to dielectric heating. The shrinkage of the width in the direction perpendicular to was 21 percent ~ 76 percent of that of the thickness of square timbers in the direction parallel to the mechanical pressure. The casehardening for all specimens was very slight because of significantly reduced ratio of the tangential to radial shrinkage of specimens and kerfing. The surface checks somewhat severely occurred although the occurrence extent of the surface checks on the kerfed specimens was slight compared withthat on the control specimen.
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Effect of Reserve Air-Drying of Korean Pine Heavy Timbers on High-Temperature and Low-Humidity Drying Characteristics

https://research.thinkwood.com/en/permalink/catalogue1506
Year of Publication
2014
Topic
Moisture
Material
Solid-sawn Heavy Timber
Author
Lee, Chang-Jin
Lee, Nam-Ho
Park, Moon-Jae
Park, Joo-Saeng
Eom, Chang-Deuk
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2014
Format
Journal Article
Material
Solid-sawn Heavy Timber
Topic
Moisture
Keywords
Moisture Content
Temperature
Humidity
Pine
Air Drying
Shrinkage
Internal Checks
Twist
Case Hardening
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
The pre-air-drying of Korean pine before the high-temperature and low-humidity drying was shown to be effective in uniform moisture content distribution and prevention of surface check. Our results suggest that initial moisture content of the timber also plays important role in high-temperature and low-humidity drying method. The pre-air-drying also helps in the reduction of surface checks in Korean pine when compared to the Korean pine dried by only high-temperature and low-humidity. End-coating was not effective in the prevention of twist, shrinkage, case hardening and internal checks. The pre-air-drying reduces the internal tension stresses which occur during high-temperature and low-humidity drying thus decreasing case hardening and also preventing internal checks. The pre-air-drying decreases the moisture content and causes shrinkage which leads to increased twist in the Korean pine.
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Free
Resource Link
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