• Journal of the Korean Wood Science and Technology
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• v.13 no.3
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• pp.27-33
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• 1985

Air-drying tests were carried out on green taun (Pometia pinnata f glabra) for 25-mm and 50-mm thickness to elucidate drying characteristics on air-drying rate, time and defects in spring and air-drying calendar. The results of this study were as follows: 1. The air-dried lumber for 25-mm thickness from an initial average moisture content (MC) of $58.3{\pm}3.5$ percent reached 30 percent MC in 17 days, 25 percent MC in 24 days, 20 percent MC in 38 days and 15 percent MC in 84 days. 2. The air-dried lumber for 50-mm thickness from an initial average MC of $59.6{\pm}5.0$ percent reached 30 percent MC in 39 days, 25 percent MC in 55 days and 20 percent MC in 84 days. 3. Air-drying calendar that could be useful in estimating drying times for each month developed by the use of climatological data for Suwon. Total number of effective air-drying days during a year were 243.5 days and the major determinant of the effect air-drying days was temperature. 4. The air-drying rates for 25-mm and 50-mm coated lumber were slight1y slower than those of uncoated lumber. The number and total length of both end checks and surface checks for end coated lumber were less severe than those of uncoated lumber.

• Journal of the Korean Wood Science and Technology
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• v.16 no.4
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• pp.10-39
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• 1988

This study investigated the temperatures and relative humidities in the semi-greenhouse type solar dryer with a black rock-bed heat storage and without heat storage and outdoor temperature and relative humidity at 9 a.m. and 2 p.m.. A comparison was made of the drying rates, final moisture contents, moisture content distributions, casehardening stresses, drying defects, volumetric shrinkage of dried lumber for solar- and air-drying from the green condition of mixtures of Douglas-fir, lauan, taun, oak and sycamore 25mm- and 50 mm-thick lumber during the same period for four seasons, and heat efficiencies for solar dryer with and without the heat storage for saving of heat energy and the cost of lumber drying using the solar energy. The results from this study were summarized as follows: I. The mean weekly temperatures in the solar dryers were 3 to $6^{\circ}C$ at 9 a.m. and 9 to $13^{\circ}C$ at 2 p.m. higher than mean outdoor temperature during all the drying period. 2. The mean weekly relative humidities in the solar dryers were about 1 to 19% at 9 a.m. higher than the outdoor relative humidity. and the difference between indoor and outdoor relative humidity in the morning was greater than in the afternoon. 3. The temperatures and relative humidities in the solar dryer with and without the heat storage were nearly same. 4. The overall solar insolation during the spring months was highest and then was greater in the order of summer, atumm, and winter month. S. The initial rate of solar drying was more rapid than that of air drying. As moisture content decreased, solar drying rate became more rapid than that of air drying. The rates of solar drying with and without heat storage were nearly same. The drying rate of Douglas-fir was fastest and then faster in the order of sycamore, lauan, taun and oak. and the faster drying rate of species, the smaller differences of drying rates between thicknesses of lumber. The drying rates were fastest in the summer and slowest in the winter. The rates of solar drying during the spring were more slowly in the early stage and faster in the later stage than those during the autumn. 6. The final moisture contents were above 15% for 25mm-thick air dried and about 10% for solar dried lumber, but the mean final MCs for 50mm-thick lumber were much higher than those of thin lumber. The differences of final MC between upper and lower course of pile for solar drying were greater than those of pile for air drying. The differences of moisture content between the shell and the core of air dried lumbers were greater than those of solar dried lumber, smallest in the drying during summer and greatest in the drying during winter among seasons. 7. Casehardening stresses of 25mm- and 50mm-thick dried lumber were slight, casehardening stress of solar dried lumber was severer than that of air dried lumber and was similar between solar dried lumber with and without heat storage, Casehardening stresses of lumber dried during spring were slightest and then slighter in the order of summer, autumn, and winter. Casehardening stresses of Douglas -fir, sycamore and lauan were slight, comparing with those of taun and oak. 8. Maximum initial checks of 25mm-thick lumber occurred above and below fiber saturation point and those of 50mm-thick lumber occurred in the higher moisture content than thin lumber. As the moisture content decreased, most of checks were closed and didn't show distinct difference of the degree of checks among drying methods. The degree of checks were very slight in case of Douglas-fir and lauan, and severe in case of taun and oak. The degree of checks for 50mm-thick lumber were severer than those for 25mm-thick lumber. 9. The degree of warpage showed severe in case of oak and sycamore lumber, but no warping was found in case of Douglas-fir, lauan and taun. 10. The volumetric shrinkages of taun and oak were large and medium in case of Douglas-fir, lauan and sycamore. 11. Heat efficiencies of solar dryer with heat storage were 6.9% during spring, 7.7% during summer, 12.1% during autumn and 4.1% during winter season. Heat efficiency of solar dryer with heat storage was slightly greater than that of without heat storage. As moisture content of lumber decreased, heat efficiency decreased.

• Journal of the Korean Wood Science and Technology
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• v.14 no.2
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• pp.36-42
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• 1986

Both the control and heated specimen of oak, hornbean, alder, poplar, red pine and pitch pine among domestic commercial species and taun imported were used for radial and tangential shrinkage and movement that occurred on changing the relative humidity of the atmosphere from 90 percent to 60 percent at $25^{\circ}C$. The results of this study were as follows. 1. The radial and tangential shrinkage of the control and heated hornbean and oak wood, except alder, of high specific gravity showed greater than species with low specific gravity. The ratio of tangential to radial shrinkage was 1.46 for taun to 2.70 for alder. Green volume specific gravity of the heated and soaked specimen of all species except poplar decreased 1.5 to 3.1 percent. Shrinkage of the heated specimen increased more than that of the control specimen, and antishrink efficiency of all timbers except alder had negative value. Shrinkage from green to air dry of treated specimens increased more than case of total shrinkage, and radial shrinkage of those specimen increased greater than tangential shrinkage. 3. The movement of the heating specimen for 120 hours decreased than those of the control and the heating specimen for 240 hours. The movement of heating oak, poplar, red pine and pitch pine (or 240 hours increased rather than those of the control specimen.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.66-71
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• 1994

To increase drying rate and reduce drying degradation, pretreatments such as prefreezing and presteaming have been widely used in wood industries. Presteaming lumbers prior to kiln drying is known positively to improve its permeability, to increase diffusion coefficient and to reduce discoloration, but negatively to increase collapse. Prefreezing lumbers prior to kiln drying is also known to reduce significantly its drying defects and its shrinkages. Thus it is no doubt that the pretreated lumbers shrink diversely from the untreated. In this study the shrinkage behaviors of the pretreated specimens are investigated by drying two tropical hardwoods (Apitong and Taun) in three different dying conditions: high temperature and slow drying rate (drying in a closed cylinder), high temperature and rapid drying rate (drying in an oven) and low temperature and slow drying rate(drying at room temperature). The prefrozen specimens show the least volumetric shrinkages in most drying conditions. The specimens dried in cylinders shrink most among all drying conditions. In general the pretreated specimens reached the 30 % moisture content faster than the untreated by about 30 %.

• Journal of the Korea Fashion and Costume Design Association
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• v.8 no.3
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• pp.73-85
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• 2006

The purpose of this study is to consider the characteristics of beauty culture in the latter period of Chosun Dynasty from the viewpoint of public morals and find out how characteristic beauty culture was developed along with traditional culture. Therefore, the clothes, the make-up, the style of beard and hair were examined and the beauty culture of women in the latter period Chosun Dynasty was considered. The changes of the beauty culture on the genre painting and the characteristics of the latter period Chosun Dynasty were analyzed. Conclusions are as follows ;First, in case of woman dress, the Korean Jergori was short and the Chima was too long. Due to the diversification of wearing, the underpants play as a decorations. Second, the hair which focus on the cleanness and the sanitation and the skin maintenance method were important. The make-up focus on make-up with powder which emphasis on the slim and round eyebrow, the small and thick lips for the beauty look of the latter period Chosun Dynasty. Third, a unmarried woman did the braids('Taun Muri') and a feme covert did 'Unseen Muri'. As people cling to the big and head of hairs gradually, the chignon('Terae Muri') was in fashion. The beauty culture in the latter period of Chosun Dynasty clothes and cosmetic treatment style were generalized through nobility, common people, lowly people. The imitation mentality which follow after Gisaeng style that led the fashion of that period was shown up. With understanding the beauty culture of the latter period of Chosun Dynasty, the study on the traditional beauty culture should be revitalized. This study help to uplift the pride on Korea traditional culture and to promote the globalization of Korean culture.

• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.8-14
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• 1997

Stress wave velocity, wave impedance, and stress wave elasticity of small, clear bending specimens of five domestic softwoods (Pinus densiflora, Pinus koraiensis, Chamaecyparis obtusa, Cryptomeria japonica, and Larix leptolepis) and four tropical hardwoods(Kempas, Malas, Taun, and Terminalia) were correlated with static bending modulus of elasticity(MOE) and modulus of rupture(MOR). The degree of correlation between stress wave parameters and static bending properties was dependent on wood species tested. Stress wave elasticity and wave impedance were better predictors for static bending properties than stress wave velocity for each species individually and for softwood or hardwood species taken as a group, even though elasticity and impedance were nearly equally correlated with static bending properties apparently. Based upon the correlation coefficient between stress wave parameters and static properties, stress wave elasticity and wave impedance were found as stress wave parameters which can be used for the purpose of the reliable and successful prediction of bending properties. The degree of correlation between static MOE and MOR was also different according to wood species tested. Static MOE was nearly as well correlated with MOR as was stress wave elasticity. The results of this research are encouraging and can be considered as a basis for further work using full-size lumber. From the results of this study, it was concluded that stress wave measurements could provide useful predictions of static bending properties and was a feasible method for machine stress grading of domestic softwoods and tropical hardwoods tested in this study.

• Journal of the Korean Wood Science and Technology
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• v.14 no.1
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• pp.45-54
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• 1986

A study was conducted to determine the physical properties related to drying characteristics, the seasonal air drying curves and the kiln drying schedule for taun lumber imported and utilized. This kiln drying schedule was found by oven drying and developed by pilot testing of green lumber and partially air dried lumber. The results of this study were as follows; 1. Average green specific gravity and standard deviation of heartwood lumber were 0.60${\pm}$0.03 and those of sapwood lumber were 0.64${\pm}$0.02. 2. Radial shrinkage from green to air dry and from green to oven dry were 3.05 percent and 5.96 percent respectively, and tangential shrinkage from green to air dry and to oven dry were 5.49 percent and 8.74 percent respectively. 3. Drying time for 25mm thick green lumber (50 percent moisture content) air dried to 30 percent moisture content were 14 days in springtime. 6 days in summertime, and 12 days in autumntime, whereas for 50mm thick lumber in 36 days in springtime, 18 days in summertime, 38 days in autumntime. 4. Kiln drying schedules developed by oven drying were T8-B3 for 25mm thick lumber and T5-B2 for 50mm thick lumber. 5. Kiln drying curves of green 25mm and 50mm thick lumber were similar to those of partially air dried lumber from the level of 30 percent average moisture content. Green 25mm thick lumber (55.7 percent moisture content) was dried to 9.3 percent moisture content in 101.5 hours and green 50mm thick lumber (65.6 percent moisture content) was dried to 11.5 percent moisture content in 526 hours. 6. End checking for green 25mm thick lumber occured in 49.6 percent moisture content and reached maximum amount in 27.6 percent moisture content and closed in 15.8 percent moisture content. 7. End checking for green 50mm thick lumber and partially air dried lumber developed and reached maximum amount earlier then for 25mm thick lumber. 8. Final moisture content of surface layer for 50mm thick lumber was one half of that of core, and moisture content equalized in the lumber after nine days of room conditioning. 9. Casehardening for 50mm thick lumber was slight and was conditioned after nine days of room stroage. 10. Drying defects, such as end checking and surface checking, were not observed and the quality of dry lumber was first.