• Journal of the Korean Wood Science and Technology
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• 제42권2호
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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.

• 한국세라믹학회지
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• 제46권3호
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• pp.301-305
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• 2009

The novel carbon coating process for interlayer of fiber reinforced ceramic composites between fiber and matrix was performed by carbonizing phenolic resin solution that coated on fiber surface in $N_2$ atmosphere at $600^{\circ}C$ to improve the strength and fracture toughness of CMC(ceramic matrix composite). 160 nm carbon layer was coated on fiber surface with 5 vol% of phenolic resin solution. Since the process temperature ($600^{\circ}C$) is lower than chemical vapor deposition($900{\sim}1000^{\circ}C$), the strength and toughness could be preserved. Furthermore the coating thickness uniformity was improved to 8% of deviation along the stacking sequence. Therefore, prevention from fiber degradation during coating process and controlling coating thickness uniformity along the preform depth were achieved by coating with phenolic resin carbonizing method.

• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.130-137
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• 2014

Nondestructive evaluation (NDE) method by using a resonance frequency mode was carried out for ceramics made from particle boards with different phenol resin impregnation ratios (30, 40, 50, 60%) at carbonizing temperature of $800^{\circ}C$. The material for ceramics was Miscanthus sinensis var. purpurascens board. Dynamic modulus of elasticity increased with increasing impregnation ratio. There was a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to modulus of rupture (MOR). However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of ceramics made from Miscanthus sinensis var. purpurascens particle boards by different phenol resin impregnation ratios.

• 농업생명과학연구
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• 제44권4호
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• pp.21-27
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• 2010

인피섬유로 한지를 제조하고 남은 닥나무 목질부를 고부가치화 하기 위하여 닥나무 목질부로 제조된 파티클보드를 이용하여 탄화온도 변화에 따른 닥나무재료 우드세라믹을 제조하여 물성을 검토하였다. 밀도, 휨강도성능, 브리넬 경도, 압축강도 등은 탄화온도가 증가할수록 증가하였으며 밀도와 휨강도성능, 경도, 압축강도사이에는 유의성이 인정되는 밀접한 상관관계를 나타내었다.

• Carbon letters
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• 제15권4호
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• pp.277-281
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• 2014

A series of high capacity soft carbons with different phosphorus contents were successfully prepared by carbonizing petroleum cokes treated with hypophosphorous acid at $900^{\circ}C$. The effect of phosphorus content on the electrochemical performance of the soft carbons was extensively investigated. The P-doped soft carbons exhibited greatly enhanced discharge capacities and outstanding rate capabilities with increasing phosphorus content. In addition, the influence of temperature on the electrochemical behaviors of the soft carbons was investigated in a wide temperature range of $25^{\circ}C$ to $50^{\circ}C$. Surprisingly, the electrochemical properties of the pristine and P-doped soft carbons were highly sensitive to the operating temperature, unlike conventional graphite. The pristine and P-doped soft carbons exhibited significantly high discharge capacities of 470 and 522 mAh/g, respectively, at a high temperature of $50^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• 제35권4호
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• pp.9-13
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• 2007

소나무로 제조된 톱밥보드를 수지함치율을 달리하여 함침한 후 $650^{\circ}C$로 탄화하여 우드세라믹을 제조하고 통전하여 이들의 전기적 성질 및 표면온도를 측정하였다. 고정저항이 작을수록 낮은 전압으로 통전하여도 우드세라믹의 표면온도가 높음을 알 수 있었으며, 저항이 클수록 표면온도를 $70^{\circ}C$ 이상 올리기 위해서는 전압을 높게해야 할 것으로 판단된다. 또한 전압을 높게 했을 때 우드세라믹에 흐르는 전류, 전력 및 표면온도는 높게 나타났으며, 동일 전압 하에서는 목표온도가 높을수록 도달시간, 전류 및 전력을 증가하였다.

• 헤리티지:역사와 과학
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• 제35권
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• pp.138-158
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• 2002

To compare and analyze technical system related to manufacturing of ironware during the period of the Three Kingdoms, an analysis was conducted on the minute system of metalwork, as study objects, of the remains of the Mt. Wolpyeong fortress wall in Daejeon in the period of capital during the era of the Three Kingdoms in the 5th century, the Sanwol-ri remains in the 6th century in Gunsan and the remains of ironware excavated from the great ancient tomb of Hwangnam of the Silla dynasty in the 5th century. The result of analysis shows that in the most of the casting products, the minute system of white cast iron were contained. While the iron part of decarbonization was in the system by casting as white cast iron in the central part, on the surface layer it was turned out that comparatively uniform 100% pearlite system of about 1~2mm degree was existing. The part of pearlite on the surface layer was caused by decarbonization, which appears in all the parts of blade front end and handle. Therefore, it was found that the iron part of decarbonization was manufactured by casting, and then was processed at the high temperature by decarbonization. For the products of forging, after processing the products on the basis of pure iron for materials, they manufactured the ironware that raises the strength by carbonizing that keeps carbon infiltrated on the necessary part, by the method of black smith welding that add pure iron to steel, or by varying the method of heat processing onto the part required of strength. Though limited, we could understand that the technical systems for manufacturing skill of ironware in the areas of Baekje and Silla were different each other. In the technical system for Hwangnam great ancient tomb in the Silla area, it is found that they had raised the strength on the necessary part by applying the steelmaking method of carbonizing in the last stage of production of products, in the meantime in Baekje area, it appears that they had produced steel in advance in the first stage of production of the products, and used the produced steel only to the necessary part.

• Journal of Biosystems Engineering
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• 제37권1호
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• pp.36-43
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• 2012

Purpose: Drying characteristics of the sliced carrot and green pumpkin were investigated by using the waste heat dryer. Methods: The effects of drying temperature ($T$) and slice thickness affecting drying time were analyzed. Mathematical models for the drying curves were determined with statistical analysis of drying data. Effective diffusivity was determined for the slices of carrot and green pumpkin under various drying conditions. Results: Drying time was reduced at the drying conditions of thinner slice and higher drying temperature. Moisture ratio ($MR$) according to drying time ($t$) was well presented as an exponential function at all of drying conditions for the slices of carrot and green pumpkin with the determination coefficient ($r^2$) of >0.99. The values of effective diffusivity ($D_{ff}$) of the slices for carrot and green pumpkin were increased with increasing the drying temperature. The relationship between Ln($D_{ff}$) and $1/T$ was linear with the determination coefficient ($r^2$) of >0.97. Conclusions: Drying model was well established as an exponential function at all of drying conditions for drying samples.

• Journal of Biosystems Engineering
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• 제24권6호
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• pp.487-492
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• 1999

One of effective utilization method of rice husk is to utilize it as culture material by carbonizing the rice husk. As a second part of a series to investigate the effective and continuous production of carbonized rice husk by a cyclone combustor, a non-slagging vertical cyclone combustor without vortex collector pocket was introduced. Isothermal and mixed firing with LPG and rice husk were undertaken in order to characterize the system. Inert rice husk was used during the isothermal test to find mass of rice husk collected. It was impossible to ignite rice husk itself over the experimental conditions considered in this experiment. Cyclone combustor was operated at temperatures of 1,273~1,473K. Detailed combustion data were obtained from a pilot unit with the air flow rate of 70m$^3$/h and rice husk feed of 2kg. The equivalence ratio ranged from 0.66 to 3.48. The auxiliary gas flow rate was varied from 3.22 to 12.86$\ell$/min. The weight reduction, pH and particle size distribution of carbonized rice husk were measured to evaluate the quality of carbonized rice husk. An analysis of exhaust gas emission was conducted to characterize the combustor. The required carbonized rice husk could be obtained at equivalence ratio of 1.68~2.17, combustor temperature of 1,273~1,373K and auxiliary gas flow rate of 3.22~6.43$\ell$/min. A method to reduce CO emissions should be employed.

• Journal of the Korean Wood Science and Technology
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• 제33권3호통권131호
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• pp.45-52
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• 2005

북양젓나무(Abies sibirica Ledeb)의 목분, 목섬유, 수피를 탄화하여 획득한 목탄의 물성과 흡착특성을 탄화온도별로 조사하였다. 전체적으로 탄화온도가 상승할수록 탄화수율은 감소하였다. 목탄의 탄소함량은 탄화온도의 상승과 함께 증가하였으나, 수소나 산소의 함량은 감소하였다. 수피탄화물은 목분 또는 목섬유 탄화물과 비교하여 탄화수율이 높게 나타났으며, 수피탄화물 내 회분함량도 상당히 높았다. 목질탄화물의 요오드흡착능은 탄화온도가 높을수록 향상되었으며, 목분이나 섬유 탄화물이 수피탄화물보다 상대적으로 높았다. 기상의 톨루엔에 대한 흡착능은 목탄 종류에 관계없이 $600^{\circ}C$에서 탄화하였을 경우 가장 높게 나타났으며, 이러한 결과는 $600^{\circ}C$에서 생산한 목탄이 비표면적과 총세공용적이 가장 크다는 사실로 쉽게 설명되어진다. 초산가스제거율은 고온탄화물일수록 크고, 암모니아 가스 제거율은 $400^{\circ}C$와 같은 저온에서 탄화한 탄화물이 높은 경향을 나타내었다. 이는 고온탄화물일수록 알칼리성을 나타내는 반면 저온탄화물은 산성을 나타내는 것에 기인하는 것으로 보인다. 따라서 목탄의 pH가 산 또는 염기성 가스 흡착능력에 큰 영향을 주는 것으로 생각된다.