• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.95-102
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• 1999

The objective of this paper was the development of boards made from waste newspapers. The boards were produced from particle ONP(old newspaper) to reduce energy consumption in the board production process. ONP boards bonded with polyurethan adhesives(PU) were produced on a laboratory scale, and their physical and mechanical properties were examined. The average density of the ONP was $0.48g/cm^3$, and the densities of the boards were $0.50-0.90g/cm^3$. Therefore, th compaction ratios of the boards were in the range of 1.04-1.88. The results obtained were as follows: 1) An increase in board density results in a corresponding improvement in bending properties. 2) An increase in board density results in increased thermal conductivity. 3) In this research, ONP board can be used only for interior applications. To gain exrerior applications, the dimensional stability properties(thickness swelling and water absorption) need to be improved.

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.470-480
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• 2023

This study aimed to develop a sound-absorbing composite using sugarcane bagasse (SB) and coffee silver skin (CS) as raw materials. The composite boards were manufactured by bonding the fibers with Melamine Urea-Formaldehyde adhesive, ensuring a consistent thickness of 30 mm. Various densities were employed, namely 380, 450, and 520 kg/m³. The samples were fabricated with different fiber ratios, including SB100%, SB75% with CS25%, and SB50% with CS50%. The sound absorption coefficient (SAC) and noise reduction coefficient (NRC) were measured using the impedance tube method within a frequency range of 63-6,300 Hz. The experimental results revealed that the mixing ratio of CS exerted a notable influence on enhancing the SAC, while the density of the composite board exhibited a significant impact on increasing both the SAC and NRC. Among the densities tested, the optimal value was observed at 520 kg/m³, yielding a SAC value of 0.65 at a frequency of 1,000 Hz and an NRC value of 0.55 for the SB50-CS50 composite plate. These findings underscore the importance of considering the CS mixing ratio and composite board density when aiming to optimize sound absorption properties.

• Journal of the Korean Wood Science and Technology
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• v.31 no.5
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• pp.15-22
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• 2003

This study was carried out to investigate the properties of sawdust board impregnated with phenol resin according to the density and resin content of board. The sawdust board were manufactured to target densities of 0.4, 0.5, 0.6, 0.7 g/cm³ and resin content of 5, 10, 15, 20% made from Pinus densiflora S. et Z., Larix. kaemferi C. and Pinus koraiensis S. et Z. The impregnation process were executed in two ways, the application of vacuum pressure then followed by atmospheric pressure, and the application of vacuum pressure with ultrasonic vibration then followed by atmospheric pressure. The density of impregnated sawdust board increased as density and resin content of sawdust board increased, but impregnation rate decreased. The density, impregnation rate, bending strength and brinell hardness of sawdust board in impregnated vacuum pressure with ultrasonic vibration then nonpressure were higher than those of vacuum pressure then nonpressure. In this results, the impregnation rate is increased in vacuum pressure with ultrasonic vibration then nonpressure, it has affected the properties of sawdust board impregnated with phenol resin.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.56-63
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• 1996

This study was to manufacture thinned wood of Larix leptolepis Gordon into Oriented Strand Board(OSB) with Urea-Formaldehyde Resin. The OSB was made of four kinds of strand in slenderness ratio 150 ; thickness $0.3{\pm}0.05mm$, $0.4{\pm}0.05mm$, $0.5{\pm}0.05mm$ and $0.6{\pm}0.05mm$, respectively length 45mm, 60mm, 75mm and 90mm. Target densities were 0.65gr/$cm^3$, 0.75gr/$cm^3$ and 0.85gr/$cm^3$. The stepwise 9 minutes-multi-pressing schedule in the maximum pressure 40kgf/$cm^2$, the minimum pressure 10kgf/$cm^2$ was applied for $400mm{\times}390mm{\times}12mm$ board at the temperature of $150^{\circ}C$ in a hot press. In MOR The OSB of thin strand thickness $0.3{\pm}0.05mm$(length 45mm) and density 0.85gr/$cm^3$ was the highest. The strand thickness had more effect on MOR than the strand length. In strand thickness $0.4{\pm}0.05mm$(length 60mm) and density 0.85gr/$cm^3$ was the highest MOE. The strand thickness and length had adverse effects on MOE each other. At internal bonding. The OSB of strand thickness $0.3{\pm}0.05mm$(length 45mm) and board density 0.75gr/$cm^3$ showed the highest value. OSB had higher IB value with thinner strand thickness. The thinner strand thickness showed the lower thickness swelling in turn $0.3{\pm}0.05mm$(length 45mm), $0.4{\pm}0.05mm$(length 60mm), $0.5{\pm}0.05mm$(length 75mm). $0.6{\pm}0.05mm$(length 90mm). Target densities 0.75gr/$cm^3$ 0.65gr/$cm^3$, 0.85gr/$cm^3$ showed in turn lower value. Finally, The OSB made of thinned wood of Larix leptolepis Gordon showed good results in laboratory experiment.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.163-171
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• 2014

Environmental issues about indoor air quality have been increased and focused on volatile organic compounds (VOCs) caused cancer, asthma, and skin disease. Reducing VOCs has been attempted in many different methods such as using environmentally friendly materials and air cleaner or purifier. Charcoal is well known material for absorbing VOCs. Therefore, carbonized board from medium density fiberboard has been developed. We assumed that the source of carbonized boards can be any type of wood-based panels. In this study, carbonized boards were manufactured from oriented strand board (OSB) at 400, 600, 800, and $1000^{\circ}C$. Each carbonized OSB (c-OSB) was evaluated and determined physiomechanical characteristics such as exterior defects, dimensional shrinkage, modulus of elasticity, and bending strength. No external defects were observed on c-OSBs at all carbonizing conditions. As carbonizing temperature increased, less porosity between carbonized wood fibers was observed by SEM analysis. The higher rate of dimensional shrinkage was observed on c-OSB at $1000^{\circ}C$ (66%) than c-OSB at 400, 600, and $800^{\circ}C$ (47%, 58%, and 63%, respectively). The densities of c-OSBs were lower than original OSB, but there was no significant different among the c-OSBs. The bending strength of c-OSB increased 1.58 MPa (c-OSB at $400^{\circ}C$) to 8.03 MPa (c-OSB at $1000^{\circ}C$) as carbonization temperature increased. Carbonization temperature above $800^{\circ}C$ yielded higher bonding strength than that of gypsum board (4.6 MPa). In conclusion, c-OSB may be used in sealing and wall for decorating purpose without additional artwork compare to c-MDF which has smooth surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.509-516
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• 2008

Multi-layer circuit card for semiconductor inspection was fabricated by LTCC technology. After a proper impedance design without electrical interference, ceramic tapes with the composition of $CaO-Al_2O_3-SiO_2-B_2O_3$ glass and $Al_2O_3$ were prepared. The electrode with silver paste printed on the tape. Printed ceramic sheets were then laminated and sintered. Densities and dielectric properties were measured. The microstructure, fracture surface of the region of via and matching state of substrate-electrode were observed. The durability of plated outside electrode were examined by hardness and scratch test.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.313-319
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• 1999

The properties of natural fiber filter are evaluated using laboratory experiments to find out the possibility of natural fiber drain as a substitute material of plastic board drain Experiments performed for natural fiber filter are effective opening size, permeability and clogging, Three filters were used in the experiment, which are constituted with the filter of different densities encircled with wefts and warps. The results were compared with those for the filter of MD88-80.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.1-4
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• 2008

Fuel cells have the potential of providing several times higher energy storage densities than those possible using current state-of-the-art lithium-ion batteries, but current energy density of fuel cell system is not better than that of lithium-ion batteries. To achieve the high energy density, volume and weight of fuel cell system need to be reduced by miniaturizing system components such as stack, fuel tank, and balance-of-plant. In this paper, the thin flexible PCB (Printed circuit board) is used as a current collector to reduce the stack volume. Two end plates are made from light weight aluminum alloy plate. The plate surface is wholly oxidized through the anodizing treatment for electrical insulation. The opening rate of cathode plate hole is optimized through unit cell performance measurement of various opening rates. The performances are measured at room temperature and ambient pressure condition without any repulsive air supply. The active area of MEA is 10.08 $cm^2$ and active area per a unit cell is 1.68 $cm^2$. The peak power density is about 210 mW/$cm^2$ and the air-breathing planar stack of 2 Wis achieved as a small volume of 18 cc.

• Ocean and Polar Research
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• v.35 no.1
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• pp.15-26
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• 2013

The toxic, Harmful Algal Blooms (HABs) caused by the Cochlodinium polykrikoides have a serious impact on the coastal waters of Korea. In this study, the acoustic detection system was developed for rapid HABs detection, based on the acoustic backscattering properties of the C. polykrikoides. The developed system was mainly composed of a pulser-receiver board, a signal processor board, a control board, a network board, a power board, ultrasonic sensors (3.5 and 5.0 MHz), an environmental sensor, GPS, and a land-based control unit. To evaluate the performance of the system, a trail was done at a laboratory, and two in situ trials were conducted: (1) when there was no red tide, and (2) when there was red tide. In the laboratory evaluation, the system performed well in accordance with the number of C. polykrikoides in the received level. Second, under the condition when there was no red tide in the field, there was a good correlation between the acoustic data and sampling data. Finally, under the condition when there was red tide in the field, the system successfully worked at various densities in accordance with the number of C. polykrikoides, and the results corresponded with the sampling data and monitoring result of NFRDI (National Fisheries Research & Development Institute). From the laboratory and field evaluations, the developed acoustic detection system for early detecting HABs has demonstrated that it could be a significant system to monitor the occurrence of HABs in coastal regions.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.223-230
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• 2014

This study examined emission characteristics of far-infrared ray, formaldehyde, volatile organic compounds and deodorization rate of particleboard prepared at different target board densities and resin content levels, using the xylem part of Broussonetia Kazinoki Sieb. The deodorization rate increased, as the target density of board and resin content increased. Emission rates of the far-infrared ray and total volatile organic compounds (TVOCs) were 0.892~0.899, and $0.074mg/m^2{\cdot}h$ for particleboard prepared with the resin content of 13% and target density of $0.6g/cm^3$ while the deodorization rate was 80~90% for the same particleboard. The formaldehyde emission factor ranged from $0.004mg/m^2{\cdot}h$ to $0.006mg/m^2{\cdot}h$ for all particleboard fabricated at different resin content and target densities. These results indicate that particleboard prepared from the xylem part of Broussonetia Kazinoki Sieb have a potential as a building construction material.