• Journal of the Korea Furniture Society
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• v.23 no.3
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• pp.324-331
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• 2012

The domestic pine was used to investigate the change of specific gravity, moisture contents, color and anatomical structure by accelerated weathering test (AWT). According to visual inspection, a few knot separation and looseness as well as considerable surface discoloration was found out. However, the crack and split of surface texture have been never occurred till the last step of AWT. On the whole, as the time of accelerated weathering test has increased, the specific gravity has decreased. Finally, after the 9th week of AWT, the specific gravity was 0.38 that reached to 82% compared to the control specimen. In case of moisture content (MC), it showed rising trend in its early stages, however, after 3th week of AWT it have displayed steady state. A deterioration of cell-wall components was not remarkably observed by scanning electron microscope (SEM), however the ray fractures of AWT specimen were observed more than those of control specimen. The full fracture of epithelial cell around resin canal was observed by optical microscope. The fracture of ray of 2th cycle AWT specimen was first, followed by 1th week and control group. A distortion of tracheid for early spring wood and fracture of epithelial cell were generally observed by a similar level, regardless of duration time of AWT. Therefore, it is obvious that increasing duration time of AWT does not affect the deterioration of micro-structure for wood members from this study. Although a considerable change of anatomical properties was not found, there is a need of further research to understand how will the changes of specific gravity and MC on the physical properties of wood member.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.114-120
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• 2009

The bark of Populus alba ${\times}$ glandulosa was collected, air-dried and extracted with 70% aqueous acetone. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography and preparative TLC on the EtOAc soluble fraction gave a grandidentatin isomer. The structure was elucidated as grandidentatin A (cis-2-hydroxycyclohexyl 6-O-p-coumaroyl-${\beta}$-D-glucopyranoside) on the basis of spectroscopic evidences such as $^1H$-NMR, $^{13}C$-NMR, 2D-NMR and MALDI TOF-MS spectrum followed by acid hydrolysis. Grandidentatin A was identified here for the first time in Populus alba ${\times}$ glandulosa bark, and to the bset of our knowledge it has not been reported in any other literature.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.300-309
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• 2009

The effective utilization of wood structure is encouraged to preserve natural resources and the global environment. Long-span and large-scale structures are preferred to promote demand for wood. This study attempts to develop new Fire-resistance Composite Material composed of Structural steel and Structural glued laminated timber for long-span and large-scale structures. Prior to take a fire-resistance test, compare properties of bending strength with Composite material composed of Structural steel and Structural glued laminated timber, structural steel and structural provides the stability of the structure, but the structural glued laminated timber has high value elasticity of bending. Using the Composite material will improve structural stability and Eco-friend construction environment.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.330-339
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• 2009

The material properties of Cedar (Cryptomeria japonica) were evaluated according to heat treatment conditions. The special focus was made on the color control of cedar wood by heat treatment. The difference of color between sapwood and heartwood could be reduced by heat treatment at a temperature above $170^{\circ}C$. Long heating time was more effective in reducing the difference. The Equilibrium Moisture Content (EMC) of heat-treated wood was as low as 50 percent. The result obviously indicates that heat-treated wood is more dimensionally stable in the change of moisture condition than the control. The heat-treated wood was also effective in increasing the durability against wood rotting fungi. However, more study is required to develop heat treatment as an environmentally-friendly technology for wood preservation without chemical. The mechanical properties of heat-treated wood showed relatively higher performance than the control in general. Meanwhile the dramatic decrease in impact bending stress due to the loss of ductility may limit uses of heat-treated wood in certain cases. There were no significant changes in microscopic structure which may cause changes in mechanical properties. Further study on the chemical analysis of heat-treated wood is needed to scrutinize the causes of changes of material properties.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.555-562
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• 2014

Characteristics of carbonized fiberboard such as chemical materials absorption, electromagnetic shielding, and electrical and mechanical performance were determined in previous studies. The carbonized board therefore confirmed that having excellent abilities of these characteristics. In this study, the effect of density on physical properties and sound absorption properties of carbonized fiberboards at $800^{\circ}C$ were investigated for the potential use of carbonized fiberboards as a replacement of conventional sound absorbing material. The thickness of fiberboards after carbonization was reduced 49.9%, 40.7%, and 43.3% in low density fiberboard (LDF), medium density fiberboard (MDF), and high density fiberboard (HDF), respectively. Based on SEM images, porosity of carbonized fiberboard increased by carbonization due to removing adhesives. Moreover, carbonization did not destroy structure of wood fiber based on SEM results. Carbonization process influenced contraction of fiberboard. The sound absorption coefficient of carbonized low density fiberboard (c-LDF) was higher than those of carbonized medium density fiberboard (c-MDF) and carbonized high density fiberboard (c-HDF). This result was similar with original fiberboards, which indicated sound absorbing ability was not significantly changed by carbonization compared to that of original fiberboards. Therefore, the sound absorbing coefficient may depend on source, texture, and density of fiberboard rather than carbonization.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.172-182
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• 2014

Extraction is a necessary element in the bioconversion of lignocellulosics to fuels and chemicals. Although various forms of chemical pretreatment of cellulosic materials have been proposed, their effectiveness varies depending on the treatment conditions and substrate. In this study, mixed hardwood (MH) and loblolly pine (LP) were pretreated with dilute acid in a 100 mL accelerated solvent extraction (ASE) at the predetermined optimal conditions: temperature: $170^{\circ}C$, acid concentration: 0.5% (w/v), and reaction time: 2~64 min. This method was highly effective for extracting the hemicellulose fraction. Total xmg (defined as the sum of xylose, mannose, and galactose) can be extracted from milled MH and LP through pressurized dilute acid treatment in maximum yields of 12.6 g/L and 15.3 g/L, respectively, representing 60.5% and 70.4% of the maximum possible yields, respectively. The crystallinity index increased upon pretreatment, reflecting the removal of the amorphous portion of biomass. The crystalline structure of the cellulose in the biomass, however, was not changed by the ASE extraction process.

• Journal of Environmental Science International
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• v.14 no.6
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• pp.521-524
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• 2005

We introduce a simplified crossing wood drain disperses rain water concentration and is used to protect the road surface from erosion due to flooding over the unpaved road. The efficiency of a simplified crossing wood drain was also investigated. A structure of simplified crossing wood drain can be produced within 10 minutes and installed within 18 minutes. The cost of the this product is 1/5 of that of the existing crossing drain product. The production and installation cost can be reduced according to dexterity. In the context of such applications, the degrees of damage for a rubber pad, which preventing the rain overflow, were varied according to their materials. A type of 8.2mm thick fabric rubber was the most suitable in this study.

• Journal of the Korean Wood Science and Technology
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• v.48 no.1
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• pp.12-21
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• 2020

For quantitative evaluation of wooden structures, the mechanical performance of members has undergone outdoor exposure tests. A year-long monitoring was conducted using an SPF species. Test groups were divided into twelve (each month) to measure the moisture content, density and ultimate load. Starting from May when moisture content of the test group was at the lowest, simple failure modes were observed more frequently during the first half of the experiment, whereas complex failure modes took over during the second half. Starting from June when moisture content of the test group was the highest, ultimate load decreased by 30% in the second half compared to the first half. A multiple regression analysis confirmed that moisture content of the test group was the variable with most effect on ultimate load of various outdoor variables, and an estimation equation of a simple regression analysis revealed that moisture content and ultimate load formed an inversely proportionate relationship. It is thought that correlational relationships of variables other than moisture content could be applied with the increase in added data amount by longer periods of outdoor exposure tests.

• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.369-381
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• 2017

The objective of this study was to compare the wood anatomical characteristics of local tree species in Moluccas, Indonesia i.e., Moluccan ironwood (Intsia bijuga), linggua (Pterocarpus indicus), red meranti (Shorea parvifolia), and gofasa (Vitex cofassus). Qualitative evaluation was conducted by observing the anatomical structure in cross, radial, and tangential sections of each sample. For the quantitative evaluation, the dimensions of vessels, rays, and fibers were measured. Qualitative evaluation showed that crystals were observed in Moluccan ironwood, linggua, and gofasa, while resin canals were only observed in red meranti. Tyloses were frequently observed in gofasa but infrequently observed in linggua and red meranti. Quantitative evaluation showed that Moluccan ironwood with the higher density had thicker fiber wall, higher quantity of ray number, and wider rays than the other species. Red meranti had higher values of ray height and fiber length than the other three species. The results also revealed that linggua showed the highest values of relative crystallinity and crystallite width. Red meranti and gofasa showed similar values of relative crystallinity and crystallite width, while Moluccan ironwood showed the lowest values. The basic qualitative and quantitative anatomical characteristics discussed could provide useful information for further utilizations of such wood species.

• Journal of the Korean Wood Science and Technology
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• v.15 no.3
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• pp.34-43
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• 1987

This study was performed to find out the types of linkage of carbohydrates in wood cell walls. To study the structure of linkage of carbohydrates in wood cell walls, we have attempted to find out the method holocellulose preparation and optimum condition of enzyme hydrolysis in holocellulose, and fractionate oligosaccharide with products that hydrolized partly by acetolysis and deacetylation in holocellulose. We have achieved four results. These results as follow; 1. At first. we reacted in wood meal $NaClO_2$ 1g per lignin lg for one hour and then the same of quantity $NaClO_2$ for four hours. Through these experiments, we have developed new holocellulose preparation method which had low loss of carbohydrates and high effect of the delignification. 2. The optimum condition of enzyme hydrolysis of holocellulose which had lignin was 0.005M sodium acetate buffer (pH 5.0). We have achieved 7.2% reducing sugar through the procedure that reactioned 0.01g holocellulose putting enzyme 0.03g for 72 hours. It may be supposed that 5.5% of lignin contained in holocellulose prevented enzyme contaction from holocellulose and so this lignin has resulted in the low efficiency of enzyme hydrolysis. 3. We did not fractionated from oligosaccharides which were preparated by the method of acetolysis and deacetylation in holocellulose. The reason is that holocellulose having a lot of lignin prevented prefectly partial hydrolysis from the method of acetolysis and deacetylation. 4. We attempted analysis of six standard substances through HPLC apparatus having sugar pak 1 column which we have changed flow rate and the column temperature variably. These six standard substances were D-glucose, D-mannose, D-xylose, D-galactose and L-rhamnose, L-arabinose, But sugar pak 1 column was not fitted analysis of four substances because D-galactose, D-mannose, D-xylose, L-rhamnose were agreement with elution time. And so, we could not analize four standard substances with sugar pak 1 column.