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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 36, Issue 6 - Nov 2008
Volume 36, Issue 5 - Sep 2008
Volume 36, Issue 3 - May 2008
Volume 36, Issue 2 - Apr 2008
Volume 36, Issue 4 - Apr 2008
Volume 36, Issue 1 - Jan 2008
Selecting the target year
Decay Resistance of Borate-Modified Oriented Strandboard: A Comparison of Zinc and Calcium Borate
Lee, Sun-Young ; WU, Qinglin ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 1~10
Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwood and southern yellow pine was investigated in this study. Brown rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolar were used to examine the decay resistance of the OSB. The OSB test specimens were colonized by brown and white rot fungal mycelium in both the brown and white-rot culture bottles after 8 and 12 weeks, respectively. The wood species and fungus type had the significant effects on the decay resistance. Brown rot decay was evident for all untreated southern pine and mixed hardwood controls. The white-rot decay, however, did not show significant weight loss at both species control samples. The incorporation of ZB and CB composites provides suitable protection against brown-and white-rot fungi. No significant weight loss was observed from the borate treated OSB.
Mechanical and Physical Properties of Zinc Borate-Modified Oriented Strandboard (OSB)
Lee, Sun-Young ; WU, Qinglin ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 11~23
The mechanical and physical properties of zinc borate (ZB)-modified oriented strandboard (OSB) from southern wood species were investigated in this study. OSB panels treated with ZB were not significantly weaker than the untreated samples in terms of specific modulus of elasticity (SMOE) and specific modulus of rupture (SMOR). ZB showed the negative effect on specific internal bond (SIB) strength, since some of ZB would persist as a powder state on the flake surfaces, thereby reducing the bonding efficiency of the adhesive. The ZB level did not show significant effect on thickness swelling (TS). ZB-modified OSB showed the suitable mechanical and physical properties for the structural wood composites.
Effect of Brown-rotted Wood on Mechanical Properties and Ultrasonic Velocity
Lee, Sang-Joon ; Kim, Gyu-Hyeok ; Lee, Jun-Jae ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 24~32
Artificial brown-rot decay was induced to two wood species, Pinus densiflora and Pinus radiata. A modified direct inoculation method was used and the decay indicators of mass loss and two compressive mechanical properties, maximum compressive strength (MCS) and compressive stiffness, were estimated over the period of 8 weeks of fungal exposure. Measurable mass loss occurred 2 weeks after the fungal attack, with 15% to 22% of the loss occurring 8 weeks after fungal exposure with Fornitopsis palustris and Gloeophyllurn trabeurn. Mechanical properties proved to be far more sensitive than mass loss detection: approximately five to six times by quantity. Of the two mechanical properties, MCS was more sensitive to and consistent with progressive brown-rot decay. An ultrasonic test was performed to determine the feasibility and accuracy of this method for nondestructive detection of brown-rot decay. The ultrasonic test is highly sensitive at qualitative detection of the early stages of brown-rot decay.
Development of Knot Quantification Method to Predict Bending Strength Using X-ray Scanner
Oh, Jung-Kwon ; Kim, Kwang-Mo ; Lee, Jun-Jae ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 33~41
This study was aimed to develop the knot quantification method to predict bending strength, using x-ray scanner. The bending strength prediction model was proposed in this paper. The model was based on Knot Depth Ratio (KDR) and closely-spaced knot was taken into account. The previous paper reported that KDR is the ratio of the knot and transit zone to the lumber thickness. Even though KDR involves transit zone, it was verified that the ratio of the moment of inertia for knot to gross cross section (
) based on KDR was a good predictor for bending strength of lumber. To take closely-spaced knot into account, a projection method was also proposed. This projection method improved the predictive accuracy significantly. It showed coefficient of determinant of 0.65 and root mean square error (RMSE) of 9.17.
Effects of Hardener and Extender Contents on Curing Behavior of Urea-Melamine-Formaldehyde Resin
Eom, Young-Geun ; XU, Guang-Zhu ; Lee, Young-Kyu ; Kim, Hyun-Joong ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 42~48
This study was conducted to discuss the effects of hardener and extender contents on peak temperature, reaction enthalpy (
), gelation time, viscosity change, and pH value in three types of UMF (urea-melamine- formaldehyde) resin with the help of perpHecT LogR meter, differential scanning calorimetry (DSC), and advanced rheometric expansion system (ARES), The results indicated that the pH value of Control A steeply decreased to 5,2 in the early stage but relatively remained constant thereafter as in Synthesis 1 and Synthesis 2, The peak temperature and time decreased as well, whereas
and viscosity increased with the increase of hardener content. On the other hand,
was not changed up to the extender content of 5% and then decreased with its further addition, And the pH value and peak temperature showed no change with the increase of extender content at the hardener content of 5% in three types of UMF resin, The effect of hardener content in this experiment, however, appeared more conspicuous in Control A than in the other two types of Synthesis 1 and Synthesis 2, These results might be caused by higher molecular weight with longer chains of methylene (
) and methylene (
) ether bridges or much more branched chains in Control A.
Effect of Drying Methods on Longitudinal Liquid Permeability of Korean Pine
Lee, Min-Gyoung ; Lu, Jianxiong ; Jiang, Jiali ; Kang, Ho-Yang ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 49~55
This study was carried to investigate the effects of steaming and four different drying methods on the longitudinal liquid permeability of Korean pine (Pinus koraiensis Sieb.et Zucc.) board. Four drying methods were air drying, conventional kiln drying, microwave-vacuum drying and high temperature drying. Darcy equation was used for calculating the specific permeability of the small sapwood specimens taken from the treated boards while capillary rising method was used for the heartwood specimens. The sapwood specimens were extracted with water and benzene-alcohol solution to examine the mechanism of liquid flow in treated wood. No significant correlation was found between specific permeability and the number of resin canals of the sapwood specimens. Extraction decreased the differences of specific permeabilities of the sapwood specimens between the five treatment methods. The effects of extraction on the longitudinal permeability are different between five treatments. The fluid path in heartwood was observed by dynamic observation method.
Rheological Properties and Particle Size Distribution of Northeast Mixed Hardwood for Enzymatic Saccharification Processing with High Substrates Loading
Um, Byung-Hwan ;
Journal of the Korean Wood Science and Technology, volume 36, issue 5, 2008, Pages 56~65
In this paper experimental results are presented for the rheological behavior of high-solids saccharification of mixed northeast hardwood as a model feedstock. The experimental determination of the viscosity, shear stress, and shear rate relationships of the 10 to 20 percent slurry concentrations with constant enzyme concentrations were performed under variable rotational speed of a viscometer (2.0 to 200 RPM) at combined temperatures (50 to
) for the initial four hours. The viscosities of saccharification slurries observed were in the ranges of 0.024 to 0.028, 0.401 to 0.058, and 0.840 to 0.087 Pa s for shear rates up to 100 reciprocal seconds at 10, 15, and 20 percent initial solids (w/v) respectively. The fluid behavior of the suspensions was modeled using the power-law, the Herschel-Bulkley, the Casson, and the Bingham model. The results showed that broth slurries were pseudoplastic with a yield stress. The model slope increased and the model intercept decreased with increasing fermentation time at shear rates normal for the fermentor. The broth slurries exhibited Newtonian behavior at high and low shear rates during initial saccharification process. The solid particle size ranged from 57.8 to
and from 44.0 to 57.5 11m for combined temperatures at 10, 15, and 20 percent initial solids (w/v) respectively.