• Journal of the Korean Wood Science and Technology
• /
• v.24 no.2
• /
• pp.26-35
• /
• 1996

4군데의 임반에서 선발된 라디에타 소나무를 공시목으로 두께 2.6mm 와 1.4mm의 단판을 제작하였다. 단판을 조합하여 만들어진 합판의 크기는 $1200mm{\times}2400mm{\times}12.5mm$이었다. 단판의 등급과 합판의 강도적 성질은 원목의 성질과 깊은 관계가 있으며, 원목의 밀도는 합판의 성질을 결정하는 중요한 인자가 되었다.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.290-295
• /
• 2000

Mechanical and physical properties of wood fiber for the reinforcement of thin-sheet cement products were investigated. The slurry-dewatering method followed by pressing was used to manufacture the products. Mechanical and physical properties of wood fiber reinforced cement composites were assessed with flexural strength, density, and water absorption. The results obtained in this study were analyzed statistically using the analysis of variance in order to derive statistically reliable conclusions.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.3
• /
• pp.25-32
• /
• 2004

This research work explored physical and mechanical properties of impregnated sawdust boards from three softwood species (P, densifora, L. kaemferi, and P. koraiensis) with phenol-formaldehyde (PF) resin by various vacuum treatment methods of combining pressure, vacuum, and ultrasonic waves. Simultaneous vacuum and ultrasonic wave treatments with no pressure resulted in the greatest increase in resin content, density, dimensional changes (thickness and length), bending strength, and hardness of impregnated board. This result seemed to be attributed to the ultrasonic wave treatment.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.6
• /
• pp.777-783
• /
• 2015

Wood is an anisotropic material that shows the changes in hardness, quality and dimensions depending on the types of cells on three cross sections, size, array and so on. It can also be used in different ways according to its use, which requires a meticulous research, in order to maximize the utilization by understanding the nature and use; and by clarifying the theory and technologies. The research on relationship among wood's physical properties, density, and elasticity of modulus have been studied in Korea and abroad, but those studies were based on correlation gained through standardized specimen. Rather, the study on complete product is rare. Moreover, the previous reports are mostly concentrating on vibration mode and batting, though the wood's physical properties as a material have not been in the main focus. Therefore, this study will carried out for analyzing MOE through figuring material property out and comparing frequency adapting to the Canadian HardMaple bat. For comparison of material properties, we studied the annual ring and density of the bat; calculated the MOE with resonance frequency and formula (ASTM C1259); and verified the repulsive force of this material. As a result, the relevance of the resonance frequency and annual ring is weak, and in comparison in the grain direction in wood, the MOE value is higher when the grain direction in wood is excited horizontally than when is excited vertically, because the material is repulsive when grain direction is horizontal.

• Journal of the Korea Furniture Society
• /
• v.16 no.1
• /
• pp.9-16
• /
• 2005

This study was carried out to displace traditional virgin wood fiber by exploded MDF-waste fiber for the manufacture of medium density fiberboard. MDF waste was exploded in condition of $215^{\circ}C,20$ minutes. The higher the mixing ratio of exploded MDF-waste fiber, the lower the MOR and IB of MDF. There was no difference of formaldehyde emission by desiccator method between virgin wood fiber and exploded MDF-waste fiber. Adding $25^{\circ}C$ of exploded MDF-waste fiber met the KS of MDF 15 type.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.5 s.133
• /
• pp.45-49
• /
• 2005

The sound absorption coefficients of three types commercial fiberboard were experimentally measured under a relatively low frequency range of 50 to 1600 Hz by the two microphone transfer function method. The sound absorption coefficient of 30 mm thick fiberboard was higher than that of 18 mm thick fiberboard at the frequency range of 50 to 1.2 KHz. The sound absorption coefficient of medium density fiberboard was a little higher than that of low density fiberboard.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2007.11a
• /
• pp.21-33
• /
• 2007

CPAM has been applied to the paper industry for the purpose of wet-end improvement for a long time. And molecular weight and charge density have been managed most important quality factors to make CPAM for this application. Recently branched CPAM was developed to improve retention and drainage characteristics and we considered branch degree of CPAM as important factor as molecular weight and charge density. In this experiment, we tried to investigate physical and chemical properties to determine branch degree and flocculation efficiency using Arbocell pulp which was recently developed micro size pulp and finally we applied retention and drainage test under the ONP stock condition.

• Journal of the Korea Furniture Society
• /
• v.17 no.1
• /
• pp.63-71
• /
• 2006

This study was carried out to resplace traditional virgin wood fiber by recycled MDF-waste fiber for the manufacture of high density fiberboard. For the recycling, MDF waste was disintegrated for 10 minutes and beaten for 15 minutes. There was no difference in formaldehyde emission by desiccator method between virgin wood fiber and disintergrated and beaten MDF-waste fiber. Fiberboard which was maded from 100% of disintergrated and beaten MDF-waste fiber showed similar physical and mechanical properties to those of virgin fiber. The yield of recycled fiber from MDF waste was 85%.

• Journal of Forest and Environmental Science
• /
• v.30 no.3
• /
• pp.259-266
• /
• 2014

Stand Density Diagrams (SDD) are average stand-level models which graphically illustrate the relationship between yield, density and mortality throughout the various stages of forest development. These are useful tools for designing, displaying and evaluating alternative density regimes in even-aged forest ecosystems to achieve a desired future condition. This contribution presents an example of a SDD that has been constructed for teak forests of Karnataka in southern India. The relationship between stand density, dominant height, quadratic mean diameter, relative spacing and stand volume is represented in one graph. The relative spacing index was used to characterize the population density. Two equations were fitted simultaneously to the data collected from 27 sample plots measured annually for three years: one relates quadratic mean diameter with stand density and dominant height while the other relates total stand volume with quadratic mean diameter, stand density and dominant height.

• Journal of the Korean Wood Science and Technology
• /
• v.48 no.2
• /
• pp.231-244
• /
• 2020

As a way of finding value-added materials from waste medium density fiberboard (MDF), this study characterized cellulose nanocrystals (CNCs) isolated by ammonium persulfate (APS) oxidation using recycled MDF fibers. Chemical composition of the recycled MDF fibers was done to quantify α-cellulose, hemicellulose, lignin, nitrogen, ash and extractives. The APS oxidation was performed at 60 ℃ for 16 h, followed by ultrasonication, which resulted in a CNC yield of 11%. Transmission electron microscope images showed that rod-like CNCs had an average length and diameter of 167±47 nm and 8.24±2.28 nm, respectively, which gave an aspect ratio of about 20. The conductometric titration of aqueous CNCs suspension resulted in a carboxyl content of 0.24 mmol/g and the degree of oxidation was 0.04. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy clearly showed the presence of carboxyl group on the CNCs prepared by the APS oxidation. The change of pH of the aqueous CNC suspension from 4 to 7 converted the carboxyl group to sodium carboxylate group. These results showed that the APS oxidation was facile and CNCs had a one-step preparation method, and thus suggested an optimization of the oxidation condition in future.