Seung Won Oh

Properties of Sawdust-Rice Husk Mixed Ceramic According to The Rice Husk Mixing Ratios

제재과정에서 발생되는 톱밥과 농업부산물인 왕겨의 활용방안을 찾고자 왕겨의 혼합비율에 따라 혼합보드를 제조하고 수지함침 및 탄화과정을 거쳐 혼합세라믹을 제조하여 왕겨의 혼합비율에 따라 물성을 조사하였다. 같은 수지함침율에서 왕겨혼합비율이 증가함에 따라 탄화 후 밀도 및 휨강도는 증가하였으나 중량감소율은 감소하였다. 또한 같은 탄화온도에서 밀도와 휨강도는 왕겨혼합비율이 40%일 때 가장 큰 것으로 나타났다.

Effect of the knife-incising pretreatment on the surface checks occurrence of red pine heavy timber after drying

The aim of this study was to investigate the effect of the knife-incising pretreatment on the surface checks occurrence of red pine heavy timber after drying. The effect of knife-incising was evaluated by comparison with surface checks which occurred in the control and kerfed material. The results revealed that the knife-incising treatment was effective compared with control in the prevention of surface checks, and the effect is similar to that of the kerfing treatment. In addition, the combination of incising and kerfing was most effective in preventing surface checks.

Electrical Properties and Far-infrared Ray Emission of Ceramics Manufactured with Sawdust and Rice Husk

This study investigated electrical properties and far-infrared ray emission according to the carbonizing temperature and phenol-formaldehyde (PF) resin impregnation ratio of ceramics manufactured using sawdust and rice husk. The far-infrared ray emission values and emission energy values decreased as the carbonizing temperature increased. The far-infrared ray emission values of the ceramics manufactured using a carbonizing process at and a board with a PF resin impregnation ratio of 60 percent was 0.930; the emission energy presented the highest value of . The electric resistance decreased as the carbonizing temperature increased. For the increase in the carbonizing temperature above , ceramics was very close to a conductor due to the small resistance. The power consumption increased by the decrease of electric resistance and increase of the electric current in the case of a higher resin impregnation ratio.

Emission Characteristics of Far-infrared Ray, Formaldehyde, Volatile Organic Compounds, and Deodorization Rate of Particleboard Prepared from Xylem Part of Broussonetia Kazinoki Sieb

ABSTRACT This study examined emission characteristics of far-infrared ray, formaldehyde, volatile organic compounds and deodor-ization rate of particleboard prepared at different target board densities and resin content levels, using the xylem part ofBroussonetia 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 0.074 mg/m 2 ⋅h for particleboard prepared with the resin content of 13% and target density of 0.6 g/cm 3 while the deodorization ratewas 80∼90% for the same particleboard. The formaldehyde emission factor ranged from 0.004 mg/m 2 ⋅h to 0.006 mg/m 2 ⋅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. Keywords : Broussonetia Kazinoki

The Manufacture of High-Density Woodceramic through the Secondary Carbonization

ABSTRACT A repeated impregnation and carbonization process was performed to prepare high-density woodceramics using MDF. The physical properties were estimated to further confirm morphologically structurally occurred changes of one-time and two-time phenolic resin treated and carbonized woodceramics. As compare one-time and two-time carbonized woodceramics, the increasing rate of weight and density declined after second carbonization as the resin impregnation ratio grew higher, and when the resin impregnation ratio was 40 percent, the weight and density of the second carbonization increased more than in the first step by 20.5% and 33.9% respectively which were the highest rates. Keywords : MDF, carbonization, resin impregnation, woodceramics 1. INTRODUCTION Woodceramics are porous carbon materials produced by high temperature carbonization of woody materials impregnated with phenol-for-maldehyde (PF) resin. The useful properties in-clude low density, hardness, and corrosion resis-tance. They process far-infrared ray emission and thermal characteristics. In addition, they are ex-pected to be used as new material for industrial purpose because they have a woody structure (Hokkirigawa et al., 1996; Oh, 2005; Oh and Byeon, 2006; Oh et al., 2000; Okabe et al., 1996; Suda et al., 1999). The properties of woodceramics are affected by a variety of factors such as the density of the wood or wood-bases materials, the carbonizing temperature, the temperature rise rate, and the cooling temperature. Moreover, resin impregna-tion ratio has an important influence on the pro-perty of woodceramics, converting the material into glassy carbon during the process of carbonization.Therefore, for the development of various ap-plications of woodceramic, it is required to re-form its intensity as much as it can be put to practical use. This is intended as a basic study of the manufacture of high-density woodceramic. For this study, first of all, MDFs (medium-den-sity fiberboards) were impregnated in liquid phe-nolic resin by the resin impregnation ratio, and