• Journal of the Korean Wood Science and Technology
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• v.15 no.2
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• pp.26-52
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• 1987

Among the diffuse-porous woods which arc dominant in Korea and used as construction materials due to their wood quality, ten species of six genus involving seven species of three genus in Betulaceae were studied on the radial variation of structural demenb. The species studied were Betula platyphylla var. japonica, B. ermanii, B. davurica, B. scstata, B. schmidtii, Carpinus laxifora, Alnus japonica, Prunus sargentii. Acer mono and Diospyros kaki. Wood fiber, vessel elements and ray increased rapidly in size from pith to a certain annual ring. After then the radial variation in size of the main structural elements seemed to be divided into three types; levelled off curve pattern indicating constant size(type I), continuously increasing curve pattern showing ever increase in size (type II) and parabolic curve pattern showing the gradual decrease after the maximum (type III), but the variation types by structural dements were different even in the same species. Based on the results from this study, it appears to be reasonable to consider the stabilized age of wood fiber, vessel elements and ray rather than considering wood fiber length in distinguishing mature woods from juvenile woods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.237-242
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• 2008

The tunic of Styela clava(SCT) consists of a proteoglycan network. Regenerated cellulose films were prepared by solution casting and coagulation of SCT in N-methylmorpholine-N-oxide(NMMO)/$H_2O$(87/13 wt%). The crystalline structure of powdered SCT was primarily that of cellulose I. The crystalline structure of SCT films exhibited a cellulose II structure, similar to that of viscose rayon. Physical characterization of SCT films and fibers revealed an intrinsic viscosity($\eta$) of 6.35 dL/g, average molecular weight($M_w$) of 423,000 g/M, and fiber density of 1.50 $g/cm^3$ with a moisture regain and water absorption of 10.20% and 365%, respectively. The results were similar to those of cellulose films regenerated from wood pulp. Films prepared with 6 wt% SCT exhibited strong tensile strength, high water absorption, and a greater degree of elongation. Scanning electron micrographs(SEM) of film cross-sections showed a layered, sponge-like structure.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.3
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• pp.17-22
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• 2005

The cleaning efficiency of papermaking felt which is contaminated with fiber fines and various micro-materials was investigated and compared between the application of enzyme and commercial detergent. It was found that the cleaning efficiency by the treatment of acidic-based detergent was more efficient than that of alkaline-based one in the conventional commercial detergent. it was also observed that the treatment design of first acidic-based detergent treatment to second alkaline-based detergent procedure was better in the cleaning efficiency, compared to alkaline based-to-acidic based one. The cleaning property of felt with enzyme was resulted in good cleaning efficiency, without any addition of surfactant. Especially, the enzyme treatment under alkaline condition (pH 10) showed a better cleaning result than that under acidic condition(pH 5). The addition of nonionic surfactant to the enzyme increased the cleaning efficiency of felt and decreased the cationic demand of wastewater. These results showed more favour than the application of conventional commercial detergent.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.28-34
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• 1998

Polyvinyl acetate emulsion has been widely used as adhesives for wood and paper, paint additives and binders for fiber, leather, and other materials because it is an excellent adhesive with many advantages including low in toxicity risks and manufacturing cost. It is expected the consumption of polyvinyl acetate emulsion as adhesives will increase in cigarette industry as well as in paperboard coating industry. Recently the operation speed of the cigarette tip wrapper increased so substantially that improvement of the emulsion properties is required including good wet tack development, narrow and controlled particle size distribution, low viscosity, etc. In this study the effects of such polymerization conditions as the type and amount of emulsifier, internal or external plasticizing, and emulsification methods on the viscosity and particle size of polyvinyl acetate emulsions were examined. Results showed that polyvinyl alcohol with a high degree of hydrolysis and low molecular weight and nonionic surfactants are superior to anionic surfactant in improving adhesion and emulsion stability. They also tend to produce emulsions with smaller particle size. External plasticization with dipropylene glycol dibenzoate was more effective in improving flexibility than internal plasticization with butyl acrylate. Monomer emulsification under high shear was more effective in decreasing the particle size.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.5
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• pp.17-25
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• 2003

The influence of base paper properties and fiber type on coating penetration was studied in terms of characterization of coating holdout using two types of hand sheets as the base paper which were prepared from thermomechanical pulp (TMP) and hardwood bleached kraft pulp(KP) sized internally with alkyl ketene dimmer (AKD). Laboratory rod draw down coater was used for surface sizing and coating application. Characterization of coating penetration was done by measuring the roughness of the backside of coating layer. The backside of the coating was exposed by dissolving the fibers in a solution of cupriethylenedimine (CEO). Data show that internal sizing of base paper is effective and surface sizing is more effective to prevent coating penetration. Comparing between the two types of base papers, backside roughness of coating layer of TMP sheet is much larger and sizing is more effective to reduce coating penetration than those of KP sheet. From the result of water absorption and sizing degree after surface sizing, it seems that internal sizing slows down molecular diffusion much more than capillary penetration, but surface sizing reduces the capillary penetration. Furthermore, predominant mechanism of water into paper of TMP sheet seems to be capillary penetration, but it is molecular diffusion in the case of KP sheet.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.04a
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• pp.113.1-113
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• 1979

Each year, vast amount of agricultural crop residues are produced (about 60 percent of the total crop production), which have not been effectively utilized because they are bulky and lignocellulosic, thus having little fuel energy per unit volume. Using treated plant residues as animal feeds could result in an ultimate saving of fossil fuel energy and a more effective utilizat ion of products created by the photosynthetic process. Feeding the residues to animals would decrease the pollution potential, but these residues are difficult for even a ruminant animal to digest. If cellulosic wastes produced from cereal grain straw and wood could be digested, land now used for producing forage add grain cnuld be shifted to food crops for humans. During the past decade, considerable efforts were made to utilize crop residues. These utilization methods can be broadly grouped into for categories: (1) direct uses, (2) mechanical conversions, (3) chemical conversions and (4) biological conversions. Agricultural crop residues consist mainly of cellulose, hemicellulose, lignin, pectin, andother plant carbohydrates. The nature of the constituents of these residues can be best utilized as one of the five FS: Fuel, Fiber, Fertilizer, Feed and Food. Many processes have teen proposed and some are in industrial production stage. However, economics of the process depend on the location where availability of other competitive products are different.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.1
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• pp.29-43
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• 1998

This study was to investigate the effect of .compressive load and cyclic humidity(2$0^{\circ}C$, 65% and 90% RH) on the physical and mechanical properties of corrugated board. Corrugated boards in the study were under compressive load and under cyclic humidity, and their properties were compared to those without load. Results were summarized as follows ; 1 Statistically significant correlation was shown between the ring crush of the boards and the compressive strength of cylinder specimen made from the boards. So we could study the compressive behavior of board with cylinder specimen. 2. The boards under the compressive load increased their moisture content and thickness much more than those without load both in constant and in cyclic RH. 3. The compressive and tensile strength of board samples were inversely and closely proportional to the sheet moisture content regardless of their load and humidity history. 4. The moisture content did not show any significant proportionality to the change of burst strength of boards within this experiment. 5. Board reconditioning in standard condition led to the recovery of the strength loss that had occurred under various load and humidity condition. 6. The handsheets prepared from the boards that had experienced compressive load and cyclic humidity, and those with no-load and 65% RH did not show any significant difference in strength properties. No physical damage or load-carrying properties of the wood fiber were observed by the compressive load and cyclic humidity history.

• Journal of Korean Society of Forest Science
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• v.82 no.1
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• pp.7-11
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• 1993

The swollen tissue of wound origin formed after nailing ㄷ-shaped fastener to a stem of Platanus occidentalis L. was compared with normal tissue in the qualitative and quantitative anatomical aspects. The swollen tissue appeared to differ from normal tissue in irregular cell orientation, occurrence of tyloses in vessel element, less common appearance of pore multiples, narrower and shorter vessel element, lower vessel frequency, shorter and highly thick-walled wood fiber, greater number of bars per scalariform perforation plate in vessel element, larger ray frequency, larger ray width and lower ray height.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.3
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• pp.55-62
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• 2015

Paper mulberry fibers have been used as fibrous raw materials for manufacturing traditional handmade paper, hanji for a long time. Compared to wood pulp fibers, pulp fibers from mulberry bast tissue have some benefits in physical and chemical properties due to their high D.P (degree of polymerization), M.W (molecule weight) and long fiber length. Specially, Korean handmade hanji shows outstanding characteristics in mechanical tensile strength, folding endurance, flexibility and long sustainable conservation properties. Therefore, hanji is widely applied to daily supplies, hygienic goods, medical supplies, clothing industries and so on. Recently, the potential demand of mulberry pulp fibers is more and more increased on the strength of high application fields. This study was focused on the possibility of wastewater recycling in unit operation systems for the development of automated mass production line. The properties and environmental loads of wastewater from debarking, cooking, bleaching and screening process were analyzed by means of COD, conductivity, turbidity and solid materials. The wastewater from debarking and cooking process was comparatively high in pollution load, and would be treated by additional approaches of chemico-physical method.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.21-24
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• 2014

In this study, we have investigated the maximum smoke density and the initial stage smoke density in order to see the characteristics of smoke release of the architectural surface materials and the architectural adhesives, using smoke density chamber. As a result of the study, polyurethane foam showed the highest smoke density index, 206.55 within 10 min. In the case of the other samples, reinforced styrofoam was followed as 39.90, general styrofoam 33.73, and glass fiber 5.40, respectively. In the intial stage of a fire, it is forecasted actually to give hardship at the clear visibility. In the case of architectural adhesives, the highest ranking was those for windows and doors 509.64, stone 275.63, wood 232.25, tile 18.65, and styrofoam 6.44 were followed, respectively. This result is an early research to show characteristics of smoke release through experiment. However, it is meaningful that this study can be used as a basic for further study on architectural fire hazard prediction.