• Journal of the Korean Wood Science and Technology
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• 제29권3호
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• pp.14-20
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• 2001

On the bending process, metal-strap plays an important role in dispersing the stress generated in wood. Therefore, the metal-strap has more influence on the property of bentwood materials. The effect of the metal-strap thickness for bentwood was examined. The effect of metal-strap on the bending properties of Korean red pine(Pinus densiflora Sieb. et Zucc.)was investigated in this research. The metal-strap thickness is divided into 4 kinds such as 1.0, 0.8, 0.6, 0.4 mm. The specimens were selected by grain such as annual ring angles, flat grain and half-edge grain specimens. As a result of this study, the bending ability of 1.0, 0.8 mm, thickness of half-edge grain specimens was better than flat grain specimens but the result of 0.6, 0.4 mm were reversed. The bending ability of half-edge grain was better than flat grain and the grade was higher. When the processed specimens were dried, the radius of curvature(ROC) was decreased became drying-stress was not perfectly dispersed. An optimum drying-condition would deminish this phenomenon.

• Journal of the Korean Wood Science and Technology
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• 제44권5호
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• pp.617-621
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• 2016

본 연구는 규제해충(이하 해충이라 칭함) 검출 건수 상위 3개국인 말레이시아, 인도네시아, 중국의 집성재 생산업체에 대한 현장실사를 통해 해충 검출 원인을 파악하여 검역 안전성 확보를 위한 적정 집성재 생산공정을 제시하고자 수행되었다. 현장실사 결과, 수입 집성재로부터 해충 검출은 생산공정상의 문제(층재의 천연건조 또는 미흡한 열기건조, 건조 층재의 부적절한 보관, 집성재의 불완전 포장)로 확인되었다. 특히 중국은 오동나무 층재를 전적으로 천연건조하는 점을 비롯하여 생산공정이 전반적으로 가장 불량하였다. 향후 수입 집성재의 검역 안전성을 확보하기 위해서는 수입업체 스스로 해외 생산업체에 층재에 기 서식하던 해충의 구제가 가능하면서 동시에 건조 층재나 완제품인 집성재에 대한 해충 가해를 예방할 수 있는 타당한 집성재 생산공정(층재의 적절한 열기건조, 집성접착 전까지 건조 층재의 밀봉 보관, 집성재의 밀봉 포장)의 적용을 요구하여 수입 집성재로부터 해충이 검출되지 않도록 해야 할 것이다.

• Journal of the Korean Wood Science and Technology
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• 제14권1호
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• pp.45-54
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• 1986

A study was conducted to determine the physical properties related to drying characteristics, the seasonal air drying curves and the kiln drying schedule for taun lumber imported and utilized. This kiln drying schedule was found by oven drying and developed by pilot testing of green lumber and partially air dried lumber. The results of this study were as follows; 1. Average green specific gravity and standard deviation of heartwood lumber were 0.60${\pm}$0.03 and those of sapwood lumber were 0.64${\pm}$0.02. 2. Radial shrinkage from green to air dry and from green to oven dry were 3.05 percent and 5.96 percent respectively, and tangential shrinkage from green to air dry and to oven dry were 5.49 percent and 8.74 percent respectively. 3. Drying time for 25mm thick green lumber (50 percent moisture content) air dried to 30 percent moisture content were 14 days in springtime. 6 days in summertime, and 12 days in autumntime, whereas for 50mm thick lumber in 36 days in springtime, 18 days in summertime, 38 days in autumntime. 4. Kiln drying schedules developed by oven drying were T8-B3 for 25mm thick lumber and T5-B2 for 50mm thick lumber. 5. Kiln drying curves of green 25mm and 50mm thick lumber were similar to those of partially air dried lumber from the level of 30 percent average moisture content. Green 25mm thick lumber (55.7 percent moisture content) was dried to 9.3 percent moisture content in 101.5 hours and green 50mm thick lumber (65.6 percent moisture content) was dried to 11.5 percent moisture content in 526 hours. 6. End checking for green 25mm thick lumber occured in 49.6 percent moisture content and reached maximum amount in 27.6 percent moisture content and closed in 15.8 percent moisture content. 7. End checking for green 50mm thick lumber and partially air dried lumber developed and reached maximum amount earlier then for 25mm thick lumber. 8. Final moisture content of surface layer for 50mm thick lumber was one half of that of core, and moisture content equalized in the lumber after nine days of room conditioning. 9. Casehardening for 50mm thick lumber was slight and was conditioned after nine days of room stroage. 10. Drying defects, such as end checking and surface checking, were not observed and the quality of dry lumber was first.

• 한국가구학회지
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• 제17권3호
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• pp.79-85
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• 2006

Temperature of board surface was monitored during drying using an IR image measurement system. Boards were water-saturated and dried at the levels of four temperatures and three air velocities. At higher DB the surface temperature increased more steeply and level off period was significantly short. At the DB temperatures of 70, 80, $90^{\circ}C$ the period where the surface temperature was equivalent to WB temperature was constant regardless of air velocity while at $60^{\circ}C$ it decreased as air velocity increased. It was confirmed that a surface transfer coefficient increased with DB temperature. Variation of temperature profile on a wood surface increased with DB temperature and air velocity.

• Journal of the Korean Wood Science and Technology
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• 제18권4호
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• pp.41-52
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• 1990

Experimental external collector type solar lumber dryer with $1.6m^2$ of collector area and $1.0m^3$ of maximum dryer capacity was designed and constructed to investigate the conditions inside and outside the dryer and collector. The efficiency of collector was calculated and numbers of drying-days and collector areas required to dry $0.2m^3$ and $1.0m^3$ of pine and oak at various an flow rate inside collector were estimated for eight cities in Korea. Average temperatures of collector-inlet and -outlet air and heat absorber were $52.5^{\circ}C$ $57.9^{\circ}C$, and $71.1^{\circ}C$. respectively at 4m/sec of an flow rate inside collector on sunny day in summer. Overall heat transfer coefficient of collector was 4.875W/$m^2^{\circ}C $ and collector efficiency was 52%. Estimated numbers of drying-days required to dry $0.2m^3$ of pine and oak from 80% to 15% moisture content at various air flow rate inside collector were 38 and 66 days. respectively. Areas of collector required to dry $1.0m^3$ of lumber at desired safe drying rate were estimated as $13.7m^2$ for pine and $16.0m^2$ for oak.

• 박물관보존과학
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• 제11권
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• pp.49-52
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• 2010

광주 신창동 저습지 출토 목제 빗은 강화제로서 세틸알콜을 이용하여 보존처리되었다. 보존처리 과정은 목제유물을 제3가부틸 알콜로 치환하고 세틸알콜을 40% 농도까지 함침시킨 후 진공동결건조하여 처리하였다. 그 결과 주목할 만한 표면결함은 없었다. 또한 54%의 중량잔존율과 길이방향 3.3%, 폭방향 2.1%, 두께방향 3.1%의 수축률을 나타내었다. 따라서 세틸알콜을 이용한 수침고목재의 보존처리가 치수안정화와 중량 잔존율 면에서 효과적이었다.

• Journal of the Korean Wood Science and Technology
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• 제21권1호
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• pp.21-38
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• 1993

In order to investigate the influence of recycling, a laboratory method simulating the papermaking process was used for assessing the effects of recycling on fiber properties. Sw-BKP, Hw-BKP and BGP were disintegrated and beaten to about 42$^{\circ}$SR-44$^{\circ}$SR by a valley beater. After beating, these pulps were dewatered by centrifuge and dried at 90$^{\circ}C$ for 72hrs. This recycling process(sequence of wetting, defiberating, dewatering and drying) was repeated seven times. Physical, mechanical and optical properties of recycled pulps were evaluated by TAPPI Standards. Morphological changes occurred through recycling process was observed by SEM. Sheet density decreased with recycling. The largest drop in density occurred during the first recycling. The porosity values decreased with recycling. Mechanical properties such as tensile, burst strength and folding endurance, decreased with recycling. However tear strength of Sw-BKP and mixtured pulp increased at the first recycling. Optical properties such as brightness, opacity and light scattering coefficient, increased with recycling. However, brightness of mixtured pulp gradually decreased with recycling. Fibrillated outer layer of the fiber was gradually removed from the surface with recycling. As a result of recycling, crinkles on the fiber surface were found to be more folded.

• Journal of the Korean Wood Science and Technology
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• 제29권1호
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• pp.9-15
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• 2001

침엽수 4수종(소나무, 잣나무, 낙엽송, 웨스턴 햄록)의 가열판 압체식 진공건조에서 소요되는 비에너지 곡선은 함수율 감소에 따라 서서히 증가, 거의 일정, 급속 증가 등 3단계의 증가 패턴을 나타내었고, 제재두께별 계산된 비에너지는 3cm 제재 0.483, 5cm 제재 0.649, 7cm 제재 0.814, 9cm 제재 0.977 및 11cm 제재 1.138kWh/kg로서 두께가 증가함에 따라 거의 직선적으로 증가하였고, 강한 건조스케줄을 적용한 비에너지는 약한 건조스케줄의 것보다 적었으며, 가열판 진공건조의 평균 비에너지는 0.712kWh/kg으로서 다른 건조법의 것보다 적었다.

• Journal of the Korean Wood Science and Technology
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• 제32권4호
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• pp.18-26
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• 2004

변장 14 cm 재장 2.4 m인 대단면재의 전도가열, 고주파가열 및 복합가열에 의한 진공건조특성을 조사하였다. 건조속도는 복합가열에서 가장 컸고, 고주파가열에서 가장 적었다. 비에너지는 고주파가열에서 가장 컸고, 전도가열에서 가장 적었다. 진공건조목재의 횡단방향 함수율분포는 전도가열과 복합가열의 경우 불록한 형태를 나타냈으나, 고주파가열의 경우는 한쪽 표층에서 반대쪽 표층으로 향해 증가하는 경향을 나타내었다. 건조목재의 재장방향 함수율은 전도가열과 복합가열의 경우 횡단면이 중심부위보다 낮았고 고주파가열의 경우 횡단면이 중심보다 높았다. 표면할렬과 횡단면할렬은 전도가열진공건조에서 가장 심하였다. 내부할렬은 어떠한 가열방법에 의한 건조에서도 발생하지 않았다. 복합가열 진공건조 특성은 전도가열과 고주파가열간의 절충된 중간적 경향을 나타냈다.

• Journal of the Korean Wood Science and Technology
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• 제31권1호
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• pp.10-15
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• 2003

본 연구는 주요 국산 활엽수재 원반에서 채취한 원주상(圓周狀)슬라이스를 오-븐에서 급속건조하면서 각 원반내 함수율의 방사방향 분포추이를 조사하기 위하여 수행하였다. 느티나무의 경우 변재부 또는 심변재경계부가 이미 섬유포화점 이하의 함수율에 도달하였으나, 최내측슬라이스는 아직도 약 40% 정도의 높은 함수율을 나타내었다. 벚나무의 경우 최내측 슬라이스와 바로 인접한 슬라이스간의 수분경사가 건조시간이 경과하면서 더욱 심해지는 경향을 보였다. 음나무 원반에서는 생재상태에서는 심재부의 함수율이 변재부보다 약 23% 정도 더 높은 분포를 보였으며, 이러한 분포유형이 평균함수율 약 15%일 때까지도 지속되었다. 참중나무의 경우 전(全)건조기간에 걸쳐 외주측의 심변재혼합 슬라이스들과 최내측 슬라이스의 함수율이 나머지 부위의 함수율보다 낮은 값을 나타내었다.