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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 28, Issue 4 - Dec 2000
Volume 28, Issue 3 - Sep 2000
Volume 28, Issue 2 - Jun 2000
Volume 28, Issue 1 - Mar 2000
Selecting the target year
Distribution of Moisture Content in Wood with Vapor Transmission Conditions
Lee, Weon-Hee ; Bae, Hyun-Mi ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 3~9
This study concerns the distribution and dependence of moisture content(MC) in wood for same thickness in different vapor transmission conditions. The specimens were disks of 70-mm in diameter and 20-mm in thickness from quartersawn lumber of Korean red pine(Pinus densiflora S. et Z.). The experiments were conducted in ten different conditions on the difference of the vapor pressures by the JIS Z-0208. The distribution of moisture content in wood can be illustrated by two straight lines intersecting at the point of about ten percent Me. On the other hand, when more or less than about 10 percent, the distribution of the Me can be illustrated by one straight lines. Therefore, it is considered that the values of 10 percent Me has no relation to the wood and experimental conditions. It's assumed that 10 percent is the boundary point at which the moisture sorption energy changes. In a previous study, diffusion coefficient is almost constant with no relation to a thickness of the woods for the constant experimental conditions. But, in this study, it seems that diffusion coefficient from the moisture gradient vary with the Me of wood in different vapor transmission conditions.
Effects of Moisture Content and Slope of Grain on Ultrasonic Transmission Speed of Wood
Jang, Sang-Slk ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 10~18
Nondestructive testing(NDT) by using ultrasonic sound is widely applied to wood for grading, moisture and defect detecting, estimating degree of decay, etc. Before practicing such application, basic relationships between ultrasonic transmission and wood properties shall be studied first. In this study, ultrasonic NDT was applied to larch and red pine to investigate the effects of moisture content and slope of grain on ultrasonic transmission speed. Specimens for testing about moisture content were prepared to have moisture content of green state, 30%, 20%, 10% and oven-dry state. Specimens for testing about slope of grain were prepared to have grain angle of 0, 15, 30, 45, 60, 75 and 90 degree in the tangential direction. Ultrasonic transmission speed was inversely proportional to moisture content in low range of moisture content under around 30% that was considered to be close to fiber saturation point. In high moisture content range above 30%, the ultrasonic transmission speed was almost constant. The same trend was observed in the relationships between compressive strength and moisture content. Slope of grain also had inversely proportional relationship with ultrasonic transmission speed and compressive strength. The relationship between compressive strength and ultrasonic transmission speed could be expressed by a linear equation.
Effects of Cross-Sectional Dimension and Moisture Profile of Small Specimens on Characteristics of Ultrasonic Wave Propagation
Kang, He-Yang ; Lee, Kwan-Young ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 19~24
Effects of the cross-sectional dimension and moisture profile of wood specimens on the ultrasonic sound velocities of radiata pine heartwood and sapwood. Each moisture profile model specimen was made by composing five wood pieces with various moisture contents. As the cross-sectional dimensions decreased the ultrasonic velocities of both heartwood and sapwood decreased by 4~8%. In the ultrasonic signals transmitted through the specimens low frequency components more dominated than high frequency components as the dimension of cross section increased. The specimens with the same average MCs and different moisture profiles showed different ultrasonic velocities. By plotting the ultrasonic velocities against the average moisture contents of the inner three pieces of the moisture profile model specimens it was revealed that three distinct plot patterns existed.
Effects of Polyethylene Addition in Particleboard
Oh, Yong-Sung ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 25~31
Low-density polyethylene (LDPE) powder was investigated as a hydrophobic additive component in particleboard (PB). PBs were manufactured using southern pine particles with a liquid phenolic resin binder at two press temperatures. LDPE at three application rates was used. PBs were tested for physical properties and water soak dimensional stability per the procedure ASTM D 1037. The results indicated that as the LDPE addition level and hot-press temperature were increased, the panel water absorption and thickness swell values decreased. However, the panel's physical properties were affected negatively by increased LDPE application rates. These results indicated that LDPE could be used only in limited amounts to improve the panel's water soak dimensional properties.
Studies on Biological Activity of Wood Extractives(II) - Antimicrobial and antioxidative compound isolated from heartwood of Zelkova serrata -
Lee, Sung-Suk ; Choi, Don-Ha ; Lee, Hak-Ju ; Kang, Ha-Young ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 32~41
Antimicrobial and antioxidative activities on heartwood extractives from Zelkova serrata were investigated to develop a natural fungicide or preservative. The ethanol extract from Z. serrata was fractionated in the order of petroleum ether, diethylether and ethylacetate to determine antimicrobial activity. The highest antimicrobial activity against the tested microorganisms was found in the petroleum ether soluble fraction. An active antimicrobial compound was isolated from petroleum ether soluble fraction, and identified as 7-hydroxy-3-methoxycadalene by
-NMR and EI-MS spectrometry. This compound showed higher antifungal activity, but lower antibacterial activity than hinokitiol(
-thujaplicin), strong antimicrobial compound isolated from Thujopsis dolabrata. Antioxidative activity was also higher than
-tocopherol and similar to BHT(butylated hydroxytoluene), one of the strongest synthetic antioxidant. As a result, it was concluded that 7-hydroxy-3-methoxycadalene isolated from Z. serrata had strong antifungal and antioxidative activities.
Studies on Biological Activity of Wood Extractives(III) -On the phenolic compounds isolated from heartwood of M. bombycis-
Lee, Sung-Suk ; Lee, Hak-Ju ; Choi, Don-Ha ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 42~48
Two stilbenoids and two flavonoids were isolated from ethylacetate fraction of ethanol extract of Morns bombycis heartwood. These four compounds were identified 2',3,4',5-tetrahydroxystilbene(oxyresveratrol), 3,4',5-trihydroxystilbene (resveratrol) as stilbenoids, and 2',3,4',5,7-pentahydroxyflavone(morin), 3,4',5,7-tetrahydroxyflavan((+)-afzelechin) as flavonoids by Mass and NMR spectroscopic analysis.
Heavy Metal Adsorption of Untreated Barks by Treatment Conditions of Aqueous Solution
Paik, Ki-Hyon ; Kim, Dong-Ho ; Kim, Seung-Ho ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 49~56
This study was designed to investigate the adsorption of heavy metal ions by untreated bark according to the treatment conditions of aqueous solution. The effect of temperature and pH of aqueous solution, particle size of bark, addition of light metal ions on the adsorption was examined, and the competition in adsorption among heavy metal ions was also evaluated. te The adsorption ratio of
increased with increasing themperature of solution from
however, it was relatively constant at temperatures between
. The adsorption ratio of
increased continuously with increasing the temperature of solution. The maximum adsorption ratio of
was noted at pHs ranged 6 to 7; however, the adsorption ratio declined sharply on either sides of the optimum. The adsorption ratio of
decreased continuously with increasing the pH of solution. The adsorption ratio increased as decreasing the particle size of bark, and there was little differences in adsorption tendency between pine and oak bark. By the addition of
(10~25 ppm), the adsorption ratio of
increased. An increase of the adsorption ratio was higher in oak bark than in pine bark. However, the adsorption ratio of
was not affected by the addition of light metal ions. As the mixed solution of 2 or 3 kinds of heavy metal ions(
) was treated with the untreated bark, the adsorption of
decreased considerably because of the competitive adsorption among heavy metal ions. Also the adsorption of
was more and less reduced. However the adsorption of
was not affected by the presence of other heavy metal ions.
Development of Carbonization Technology and Application of Unutilized Wood Wastes(II) - Carbonization and it's properties of wood-based materials -
Kong, Seog-Woo ; Kim, Byung-Ro ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 57~65
Objective of research is obtain fundamental data of carbonized wood wastes for soil condition, de-ordorization, absorption of water, carrier for microbial activity, and purifying agent for water quality of river. The carbonization technique and the properties of carbonized wood wastes(wood-based materials) were analyzed. Proximate analysis showed the wood-based materials contains 0.37~2.27% ash, 70~74% volatile matter, and 17~20% fixed carbon. As carbonization temperature was increased, the charcoal yield was decreased. However, no difference in charcoal yield was found due to time increase. The specific gravity after the carbonization decreased about 30~40% comparing to green wood. The charcoal had 1.08~4.18% ash, 5.88~13.79% volatile matter, and 80.15~90.94% fixed carbon. The pH of plywood and particleboard(pH 9 at
, pH 10 at
) made charcoals was higher than that of fiberboard. The water-retention capacity was not affected by the carbonization temperature and time. The water-retention capacity within 24h was about 2~2.5 times of sample weight, and the Equilibrium moisture content(EMC) became 2~10% after 24h. EMC of charcoal from the thinned trees were 9.40~11.82%(
, RH 90%), 6.87~7.61%(
, RH 65%), and 1.69~2.81%(
, RH 25%). EMC of charcoal from the wood-based materials under
, relative humidity(RH) 90% was similar to EMC of charcoal from the thinned trees(9~11 %). However, under
, RH 25.65%, EMC of charcoal from the wood-based materials were higher(2~3%) than EMC of charcoal from the thinned trees. Every charcoal from the wood-based materials fulfilled the criteria in JWWA K 113-1947.
Bioactivities of Several Functional Hardwood Trees
Bae, Young-Soo ; Ham, Yeon-Ho ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 66~74
Wood of black locust(Robinia pseudoacacia) and bark of poplar(Populus alba x glandulosa), ash(Fraxinus rhynchophylla) and elm(Ulmus davidiana var. japonica) trees were collected, extracted with acetone-
(7:3. v/v), fractionated with hexane, chloroform, ethylacetate and
. then freeze dried to get some dark brown powder for bioactive tests. Decay-resistant activity was tested using wood block specimens from the hardwood trees and expressed by weight loss rate. Black locust specimens indicated the best anti-decaying property and poplar blocks were the worst. Antimicrobial and antioxidant activities were also investigated against each wood or bark extractives. Antifungal and antibacterial activities did not indicate any significant differences among the tested fractions. In antioxidant activity.
-tocopherol one of natural antioxidants. and BHT, one of synthetic antioxidants, were used as references to compare with the antioxidant activities of the extracted fractions. Ethylacetate fraction of ash bark indicated the highest activity besides BHT in this test and all fractions of black locust extractives also indicated higher activities compared with the other fractions.
Heavy Metals Adsorption by Phosphorylated Wood and Bark
Paik, Ki-Hyon ; Kim, Dong-Ho ; Lee, Dong-Heub ;
Journal of the Korean Wood Science and Technology, volume 28, issue 2, 2000, Pages 75~79
To improve the adsorption of heavy metal ions in aqueous solutions. sawdust and bark of pine (Pinus densiflora) and oak(Quercus accutisima) were phosphorylated. The phosphorylated sawdust and bark contained phosphorous of 1.2~1.3% in the treatment for 1 hr and 1.4~1.7% for 2 hrs regardless of species and tree segments. The sawdust indicated considerable increase in the adsorption ratio of
, however the adsorption of
was a little increased. The pine sawdust was more effective in the adsorption of heavy metal ions than that of oak. While the bark indicated little adsorption efficiency of heavy metal ions.