• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.112-122
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• 2001

Laccase enzymes from Cerrena unicolor and Trametes versicolor were immobilized on the activated glass beads (CPG), silica gel (SG) and soil (SL). The heterogeneous matrices were activated by ${\gamma}$-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA), and their surfaces were coated by keratin (KER) on activated or non-activated CPG, SG and SL. The laccase activities were tested in the aqueous solution for the native and immobilized preparations using different pH and temperature conditions. By keratin coating on supports, in the cases of CPG-KER and SL-KER, the immobilization yield was increased from about 80% to 90%. Moreover, much less protein was immobilized in keratin coated matrices than in inorganic ones alone (e.g. on CPG-KER 57.6%, whereas on CPG alone 80.6%). Laccase immobilization on keratin coated inorganic matrices was generally more effective than that of non-coated matrices. Concerned to pH dependency, the optima pH for immobilized laccases generally shifted towards to higher values, 5.5-5.8 and even 5.9 in the case of keratin for C. unicolor and from 5.3 to 5.7 for T. versicolor, respectively, and decreased less gradually both in acidic and alkaline regions. The immobilized laccase was more stable against thermal denaturation. This seems particularly true at $75^{\circ}C$ in the case of C. unicolor, where the activity of immobilized enzyme is > 50% higher than that of the free enzyme. For T. versicolor the respective values were $65^{\circ}C$, and 50%.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.52-58
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• 2004

Oak is one of major species in this country as well as pine, but has been less utilized because of its refractory properties. The purpose of this study is to develope an effective method for drying the boards and disks of Quercus variabilis. Among four end-coaters used in this study thick coating with polyvinyl acetate chrolide glue (PVAc) was proved as the most effective. The average air-drying rate of boards was 1.2%MC/day, which did not exceed the safe drying rate recommended by United States Department of Agriculture (USDA). The kiln drying schedule used in this study gave a good result in drying the air-dried boards to 8%MC without any internal checks. An attempt to prevent oak disks from V-cracking during air-drying using special pallet-type stickers was not successful.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.440-449
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• 2015

Pine wood nematode (PWN), Bursaphelenchus xylophilus is one of the most serious pests of pine tree. Trunk injection of some nematicides in tree is well known as an effective control method. However there are some limitating factors which hindering the efficacy of trunk injection in field or potted tree. In this study we suggested easy and useful alternative screening methods of nematicides against PWN. Reproduction of PWN was influenced by tree twig moisture (high reproduction in high moisture trig) and paraffin coating was 78.6% reduced moisture loss in tested twig. There were no reproduction different in up and down site from infection site of twig at 1 month after inoculation of PWN and also distance (5 and 10 cm) from inoculation site of PWN did not influence the reproduction of PWN. Numbers of reproduced PWN were higher with decreasing diameter of twig. Numbers of reproduced PWN were similar to P. thunbergii and P. densiflora. However reproduction was increased depending on high inoculation density and longer propagation period. When inoculation of PWN on cut twig injected with emamectin benzoate 2.15% EC and morantel tartrate 8% SL in trunk of Pinus thunbergii in the field, PWN number were significantly reduced than untreated control. We suggest this screening method for PWN control agents.

• Journal of the Korean Wood Science and Technology
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• v.2 no.2
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• pp.5-7
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• 1974

1. This study indicates that above the fiber saturation point the drying rate can be increased with increasing the velocity of the air circutation, i.e., the drying rate of sample boards is proportional to the air velocity, but below the fiber saturation point, the effect of the velocity of air circulation is very low as shown in Figs. 1 and 2. 2. Under the controlled temperature and humidity in the kiln, the more the sample boards have moisture, the higher drying rate of it can be obtained. In other words, this means that even though in the case of drying various moisture content of wood, at the final drying stage, approximately the same percentage of moisture content of wood can be secured by employing the higher velocity of air circulation. 3. This study shows that the rate of drying in kiln changes distinctly at the fiber saturation point, i, e., above the fiber saturation point, the drying curve shows concave aginst the X axsis, but below the fiber saturation point, in the range from 30 percent of moisture content to 20 percent of moisture content, the curve shows convex as shown in Fig. 3. As the drying progresses, however, the drying curve shows concave again below 20 percent of moisture content. This means that inflection point of drying curve may be located clearly at the fiber saturation point, i.e., 30 percent of moisture content. As mentioned above, the 30 percent of moisture content of wood at which the inflectional point appears can be recognized as a critical point, i. e., the fiber saturation point at which all free water was removed from wood. The existence of inflectional point indicates that the evaporation of hygroscopic water in a cell wall is more difficult than the evaporation of free water in a cell cavity and the minor space of cell wall. The convex curve in the range of moisture content from 30 percent to 20 percent means that the evaporation of capillary condensed water has a tendency of the same rates of drying approximately, but as approaching to the 20 percent of moisture, the transfusion of moisture from wood becomes difficult because of having less moisture in cell wall. Below 20 percent of moisture content, the drying curve shows concave again, which means that it is difficult to remove the moisture located nearer to the surface of cellulose molecules and the surface bound water. These relations were revealed in Fig. 4. In comparison AC curve which does not have the two inflection points with BD curve which has two inflection points, i.e., Band D, they are mentioned already, by existence of the inflection points, the curve BD shows that the change of drying rate in the interval from 20 percent of moisture content to 30 percent of moisture content is not greater than in the case of the curve AC in the same interval. At the inflection point of 30 percent of moisture content, it can be noticed that the changing of the drying rate is very conspicuous. This phenomenon also can be recognized, as it is noticed by the Fig. 3, the drying rate from green to 30 percent of moisture content is very great. But the inclination of the curve is very slow from 30 percent of moisture content to 20 percent of moisture content, i.e., the inclination of the curve becomes almost horizontal lines. Acknowledgments Gratitude is expressed to Fred E. Dickinson, Professor of 'Wood Technology, School of Natural Resources, University of Michigan, USA for his suggestion to carry out this study.

• 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.

• KIEAE Journal
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• v.10 no.6
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• pp.115-121
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• 2010

This paper is an outgrowth of many years of practicing real interior work projects and one of my responses to the question not only about the actual dimension of interior work surface but also about the classification of contemporary finishing materials in basic interior project of high-rise apartment houses. For this purpose, 8 conventional apartment units which are already-built or designed have been surveyed and the results are interpreted in the form of proportion of space and finishes. The data can be applied to make up a schematic design in the selection of environment-friendly interior works and assessment of the degree of sustainability. For further study, the basic data provided here can be used as an index to differentiate the occupants' desire toward green interior design for their own apartment spaces, comparing to the conventional interior work in the Korean market. Not surprisingly, wall paper is dominated to make the interior surface in apartment houses. In the percentile of the utilization of finishing materials, wood-flooring and coating materials like wet paint also ranked at the upper position.

• Fire Science and Engineering
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• v.29 no.1
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• pp.12-18
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• 2015

This study has conducted an experiment of comparing the flame resistant performance and combustion characteristics according to flame resistant treatment using the Cypress Luba and particle board that is commonly used for interior decoration and furniture. As a result of testing the flame resistant performance of Cypress Luba, the Cypress Luba injected with flame resistant resin using the vacuum pressure treatment has shown to have better performances (carbonized area 9.55% and carbonized length 22.91%) than the Cypress Luba treated with flame resistant coating having rubberized plastic components on its surface. For particle board, the specimen attached with fireproof film was identified to be better (carbonized area 40.10% and carbonized length 43.40%) than the specimen with non-fireproof film. For the results of combustion characteristics using the Cone Calorimeter, the specimen treated with flame resistant coating on the surface had faster ignition than the Cypress Luba injected with fire resistant resin using vacuum pressure treatment, and in the total release of calories, the Cypress Luba injected with fire resistant resin using vacuum pressure had $68.2MJ/m^2$, and the specimen treated with fire resistant coating on the surface had $111.52MJ/m^2$. For the particle board, the ignition time had a little difference but in the total release of calories, the specimen attached with fireproof film had $90.1MJ/m^2$ and the specimen with non-fireproof film had $107.6MJ/m^2$.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.18-24
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• 2020

The purpose of this study is to validate thermal hinderance effects, i.e., feasibilities, of fire-proof structure for LPG tank exposed to fire from adjacent burning building. The panel materials suggested for the fire-proof structure are (1) 10 mm-thick wood, (2) wood with fireproof coating, (3) 75 mm-thick Expanded Polystyrene, (4) 75 mm-thick glass wool filled sandwich panel, and (5) 75 mm-thick autoclaved lightweight concrete. The square planar fire source of 1 ㎡, a matrix of nozzles releasing 120-140 g/s of LPG, is used to heat up the wall and the tank beyond, mimicking heat transfer from burning exterior wall finishes. The feasibility is tested by inspecting structural integrity after test, and then by examining temperatures at both sides of panels and tank's front surface as well as heat fluxes. As a result, it can be concluded that, among the suggested sample materials, fire-proof wall with ALC panel only showed the feasibility for explosion prevention with the proven evidences of structural integrity and least increase in temperature of tank.

• Journal of the Korean Wood Science and Technology
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• v.31 no.4
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• pp.81-90
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• 2003

In this study, we investigated the weathering properties of Korean Rhus lacquers containing tung oil and their potential use as exterior coatings. The finished lacquers were prepared with a raw Korean Rhus lacquer or refined Korean Rhus lacquer content of 10, 20, 30 and 40 wt.% (corresponding to ratios of 10/90, 20/80, 30/70 and 40/60 by weight of Korean Rhus lacquer/tung oil, respectively). The curing temperature of the prepared lacquer increased with increasing the content of the raw Korean Rhus lacquer. This increased curing temperature is related to higher proportion of hydroxyl groups in the prepared lacquer, due to the content of the raw Korean Rhus lacquer. In accelerated weathering testing, the changes in the gloss and contact angle of the prepared lacquers showed a similar trend to that of traditional exterior oil stain. In addition, the prepared lacquers containing tung oil showed greater discoloration than traditional exterior oil stain. However, the discoloration of the prepared lacquer with a raw Korean Rhus lacquer content of 40 wt.%, and that of the prepared lacquer with refined Korean Rhus lacquer contents of 30 wt.% and 40 wt.%, showed a similar trend to that of traditional exterior oil stain. Consequentially, these prepared lacquers showed a potential for being used as exterior coatings.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.198-204
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• 2014

BACKGROUND: Caused by cultural environment, the fruit skin stain results in serious damages to pear fruit. Particularly susceptible to this damage, 'Niitaka' pear accounts for 82% of pear cultivation in Korea and many farmers growing the pear trees have suffered economic losses due to fruit skin stain. This study investigated the effect of different treatments of 'Niitaka' pear during growing period on the occurrence of fruit skin stain. METHODS AND RESULTS: The treatments in the field included gibberellin (GA) paste, spraying with amino acid tree fertilizer, functional bagging, and coating of the inner paper bag with agents. The relationships between tree vigor, mineral nutrition concentration and fruit skin stain occurrence were also investigated. The fruit skin stain symptoms occurred from young fruit (May 25) until harvest. There was no exposed fruit flesh. The occurrence of fruit skin stain was significantly reduced in normal tree (shoot length 110 cm), as well as using GA paste treatment, and bagging in calcium and lime sulfur coated bags. However, spraying with amino acid tree fertilizer made no difference in comparison to control. In addition, bags in which the inner paper was coated with lime sulfur and soybean oil resulted in chemical injury to the fruit skin caused by bagging. The K concentration of shoot wood and fruit skin were higher than those of the control. Also, there were lower T-N, K concentration of leaf. CONCLUSION: These results suggest that occurrence of fruit skin stain in 'Niitaka' pear fruits during the growing period can be reduced by GA paste and bagging in calcium and lime sulfur coated bags. The symptoms of chemical injury to the fruit skin caused by bagging in lime sulfur and soybean oil coated inner paper were different compared to skin stain occurring in fruit during the growing period.