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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Wood Science and Technology
Journal Basic Information
Journal DOI :
The Korean Society of Wood Science Technology
Editor in Chief :
Volume & Issues
Volume 29, Issue 4 - Dec 2001
Volume 29, Issue 3 - Sep 2001
Volume 29, Issue 2 - Jun 2001
Volume 29, Issue 1 - Mar 2001
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Relationship between Softwood Lumber Thicknesses and Drying Rate and Drying Time Factor in Vacuum-Press Drying
Jung, Hee-Suk ; Lee, Jun-Ho ; Kang, Wook ; Lee, Nam-Ho ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 1~8
Red pine (Pinus densiflora), white pine (Pinus koraiensis), larch (Larix leptolepis) and Western hemlock (Tsuga heterophylla) lumber were vacuum-press dried under three drying schedules to investigate current moisture contents (MC), drying rates and drying time factors related to five lumber thicknesses of 3, 5, 7, 9 and 11cm. Current MC could be estimated by drying factors such as lumber thickness, initial Me and drying time. Average drying rate from 30% to 15% Me was the highest for Western hemlock below fiber satuartion point, red pine, white pine and larch in the order of their magnitude. Drying rate curvilinearly decreased as lumber thickness increased. Drying time factor curvilinearly increased as lumber thickness increased.
Energy Consumption in Vacuum-Press Drying of Some Softwood Lumbers of Different Thicknesses
Jung, Hee-Suk ; Lee, Jun-Ho ; Kang, Wook ; Lee, Nam-Ho ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 9~15
Specific energy curves for water removal in vacuum-press drying of different thick softwoods of red pine (Pinus densiflora), white pine (Pinus koraiensis), larch (L. leptolepis) and Western hemlock (Tsuga heterophylla) were split into three sections: increased slowly, fairly constant, and increased rapidly. Calculated specific energy for 3, 5, 7, 9 and 11cm thick lumber was a value of 0.483, 0.649, 0.814, 0.977 and 1.138kWh/kg of water, respectively. Specific energy almost linearly increased as lumber thickness increased, and specific energy for severe schedule was less than that for mild schedule. Average specific energy was 0.712kWh/kg and vacuum-press drying consumed less energy as compared with any other drying methods.
Improvement of Sound Absorption Capability of Wood and wood-based Board by Resonant Absorption
Kang, Chun-Won ; Park, Hee-Jun ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 16~21
Improvement of sound absorption capability of wood and wood-based board by resonant absorption was attempted. Sound absorption coefficients of wood and wood-based board which contain normal, simple perforation and stair type perforation had been estimated by the tube method using standing wave ratio. Sound absorption coefficients of wood specimens of simply perforated and perforated with stair were higher than that of normal specimens. Especially, in case of stair type perforation, it was about 50 to 60% higher than that of normal specimen in the frequency of 3 to 4KHz. It was considered that the cavity which had been formed by perforation with stair type behaved as a single resonator. Wood-based board showed good sound absorption coefficients in the frequency from 125Hz to 2KHz and that of perforated board showed a little higher in the frequency from 300Hz to 500Hz than that of normal board. The computed data of resonant frequencies at several sizes of cavity showed good accordance with the estimated data of those.
A Study on Mechanical Properties of Strand/Particle Composites (II) - Measuring of Young's Moduli and Estimating of Anisotropy Using an Ultrasonic Method -
Kim, Yu-Jung ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 22~30
Composites with various layer constructions involving the ratio of S/P were produced from wood strands(S) and particles(P) (Cryptomeria japonica D.Don) to measure various Young's moduli and anisotropy by ultrasonics. As a result, static Young's moduli of composites were almost same as dynamic Young's moduli obtained from natural frequency. However, these were smaller than those evaluated from ultrasonic wave propagation velocity. The differences between propagation velocity of the parallel(
) and perpendicular(
) in-plane direction resulted in a tendency of anisotropy. The tendency of anisotropy was larger in three-layer constructions than in seven-layer constructions. The differences of strand surface layers showed larger values than those of particle surface layers. Also, composites with higher weight ratio of strand had a tendency to propagate rapidly in each direction. In contrast to these results, the propagation velocity in the thickness direction had a tendency to propagate rapidly in composites with particle surface layers and the lower weight ratio of strand.
Study on Refining Technique of Raw Lacquer (I) - Properties of Raw Lacquer, Refined Lacquer and Film according as Their Collecting Places and Seasons -
Song, Hong-Keun ; Han, Chang-Hoon ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 31~42
In this study, we obtained fundamental data about Korean raw lacquer's physical and chemical properties to produce high quality lacquer. The tested raw lacquers were obtained from Won-ju in Korea, Shanxishang, Guizhoushang, Anhuishang in China. The drying time of refining lacquers, tensile strengths of dried films and uniformity of films are measured. The refined lacquers were prepared by experimentally scaled refining equipment. Films of lacquer were applied on glasses by film applicator. This films were tested by universal strength test machine. The films were pictured by scanning electron microscopy and confocal microscopy to define the uniformity of them. The refining method were not different among three different kind of raw lacquers which were different their collecting time and places. But the viscosity of them were quite different. When black refined lacquer is made with iron powder, the adding time of iron powder is critical to control the viscosity of it. The refining times, viscosity and tensile strength of refined lacquers were not depended the method of refining condition but the place of collecting of raw lacquer.
Study on Refining Technique of Raw Lacquer (II) - Refining and Mechanical Properties of Refined Lacquer according as Mixing Rate of Components -
Song, Hong-Keun ; Han, Chang-Hoon ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 43~51
When percentages of the component of raw lacquer were changed by adding each components that is urushiol, polysaccharide and glycoprotein, the physical properties of refined lacquer were changed and the period of refining also were changed. When polysaccharide component extracted from raw lacquer was added in raw lacquer, the period of refining was shortened about 1/3 times and this refined lacquer film was dried faster than the refined lacquer which was not added any other components. When urushiol extracted from raw lacquer was added in raw lacquer, the transparency of dried film was improved. A case of Guizhoushang was improved of the tensile strength of dried film. When both urushiol and polysaccharide were added in raw lacquer, the drying time of refined lacquer was shortened and the tensile strength of them also was improved.
Fixation characteristics of CCA and CCFZ in Japanese Red Pine, Japanese Larch, and Ezo Spruce Sapwood
Kim, Gyu-Hyeok ; Kim, Hyung-Jun ; Kim, Jae-Jin ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 52~59
The fixation characteristics of CCA and CCFZ in Japanese red pine, Japanese larch, and ezo spruce sapwood were compared at various temperatures and fixation conditions (drying and nondrying fixation). Fixation was monitored by the rates of reduction of hexavalent chromium to trivalent one, and optimal fixation time was estimated based on the results. The rate of fixation was highly temperature dependent, and the fixation rate of treated wood conditioned under nondrying conditions was much more faster than that under drying conditions, especially when the moisture content of treated wood was below fiber saturation point. Preservative types affected fixation; CCA-Type B had the highest fixation rate, followed by CCA-Type C and then CCFZ. The differences in fixation rates of preservative components were also observed among wood species; Japanese red pine fixed the fastest, followed by Japanese larch and then ezo spruce. Time required to complete fixation according to the fixation temperature could be predicted successfully using the regression equations between the temperatures and fixation time, regardless of conditioning methods, preservative types, and wood species.
Cellulose Structures of Primary and Secondary Tissues in Pinus densiflora S. et Z.
Kim, Nam-Hun ; Lee, Kee-Young ;
Journal of the Korean Wood Science and Technology, volume 29, issue 1, 2001, Pages 60~67
The microscopic characteristics and cellulose structures of primary and secondary tissues in Pinus densiflora S. et Z. were examined. Cells of primary tissue in cross section showed an irregular arrangement and round shape. Fiber lengths were 200 to
in primary tissue, and 1,500 to
in secondary tissue. Cell diameters in primary tissue were larger than those in secondary tissue; 40 to
in former and 10 to
in latter. Crystallite width and d-spacing of (200) in both tissues did not show any significant differences. However, crystallinity indices by Segal's method showed significant differences as 23% in primary tissue and 35% in secondary tissue. In the orientation of cellulose microfibril, primary tissues had a random pattern, whereas, secondary tissues presented an oriented pattern with 20 to 30 degree. The cellulose crystalline of primary tissue was easily transformed into cellulose II by mercerization, but that of secondary tissue hardly transformed. It is considered that the difference of crystal transformation in both tissues could be caused by the difference of lignification.