• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.929-934
• /
• 1997

In the present industry, there are necessary to cut not only iron metals but also non-ferrous metals such as aluminum, brass, plastic and wood(Paulownia).therefore it had been made the studies of non-ferrous metals by many scientists. we hope this kind of study will continue. The purpose of this study is to conduct the basic experiment about influencing of the feedrate adjustment and the change of the side rake angle at turning of non-ferrous metals. As the results, the surface roughnesses and Cutting force adjustments were on the decrease with a side-rake angle and feedrate diminution in the case of the plastic, brass, aluminum, and paulownia

• Journal of the Korean Wood Science and Technology
• /
• v.24 no.1
• /
• pp.75-80
• /
• 1996

The purpose of this study is to clarify the mechanism of moisture transfer depend on the thickness of the spruce(Picea sitchensis Carr.). Therefore, as the basic research of moisture transmission, the amount of moisture transmission and the moisture distribution in specimens and temperature of it's surfaces in vapor transmission process were investigated. The experiment was conducted in a steady state. and the moisture distribution was measured by knife cutting and weighing the specimens. The following conclusions were obtained ; 1. It can be found that distribution of moisture in the specimen can be approximated by two different straight lines intersecting at nine or ten percent moisture content. The amount of moisture movement defends on the gradient of moisture in the wood. 2. It is investigated that the wood surface moisture contents(MCs) are less for thinner specimens than for thick ones on the absorption side. On the other hand, the wood surface MCs are greater for thinner specimens than for thick ones on the desorption side. The main factor that affects the EMC of wood would be temperature when the relative humidity of atmosphere is constant. The specimen generate heat with the absorption and desorption process. In addition, the velocities of moisture transmission varied with the thicknesses of specimens. If the temperature of wood becomes greater, its MC decreases. Then the difference between surface MC and EMC of adsorption and desorption side becomes greater for thinner specimens. Therefore it is considered that the coefficients of moisture transfer decreases with the increases of the specimens' thicknesses.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.3
• /
• pp.45-54
• /
• 2014

The average injury rate in sawmilling industry for the last 5 years is 4.99%, which means that more than 200 injuries have occurred in that industry every year. Because the first step in risk assessment is the hazard identification, it is very important to know how to define the hazard and nature of harm. We analyzed 643 accident records of three years(2010-2012) and carried out site survey for the same cases. As a result, the most common types of work at the time of injury in sawmilling industry were removing jammed wood 81(12.8%), wood carrying task 52(8.1%), wood cutting 49(7.6%), travelling table log band saw 41(6.4%), maintenance 37(5.8%) etc. In addition, there were statistically significant differences in some analysis factors such as injured body parts, employment size, and handling material among different working places. Therefore, it is concluded that differentiated prevention efforts are necessary in each workplace.

• Journal of Forest and Environmental Science
• /
• v.33 no.4
• /
• pp.355-360
• /
• 2017

This study was aimed to analyze the increased forestry incomes by combining timber production and wood processing, which is one of 6th industrialization types in Korean forestry. The selected household has been engaged in forestry for two generations and they produce timber and associated wood products in their own facility. The wood products include dimension lumber, interior wood material, cutting board, and cube chips, the household also utilize logging and sawmill residues as well as seed and seedlings as by-products. Incomes and expenses that have been incurred on individual processes of the sequential timber production and wood processing were surveyed, and we analyzed the economic outcomes of entire business. The results of this study indicate that the gross income of the household is 122.3 million Korean won and the net income is 93.6 million Korean won. The net income of the household is approximately 2.8 times higher than the average net income of whole households in the forestry of Korea in 2016, which is approximately 4.3 times higher than that of households that have been particularly engaged in timber production over the country. We found that the 6th industrialization by combining the two sequential processes creates approximately 3.2 times as much added value compared to the case relying on timber production only.

• Journal of the Korea Furniture Society
• /
• v.18 no.4
• /
• pp.317-323
• /
• 2007

Almost all the people, particularly the rural people are directly dependent on the continued productivity of natural resources, like water, soils, forests and fisheries. But the overuse by the extremely high population pressures has degraded the natural resources into severe widespread deforestation. The degradation of natural resources, particularly the plant resources has been a great concern for socio-economic and sustainable development of the country. The Forests in Bangladesh have been depleted and degraded in volume, area, and quantity, thus requiring urgent forest protection by identifying the causes of forest loss. There are so many causes of deforestation and loss of genetic resources such as; the timber industry, which, legal or not, are cutting too many trees; indigenous forest dwellers, having their own types of problems; migrants, who, because of problems in their places of origin, have decided to move to the forests and the government through its Forest Department which is not able or willing to implement suitable policies to regulate the cutting trees and to prevent illegal cutting. Because it is a time consuming task to mitigate the first and second sets of factors, we recommend involving forest dwellers in forestry practices as much as possible and taking necessary steps to alleviate the third and fourth sets and thereby reduce the rate of forest depletion. Accordingly, a number of strategies that should be adopted to halt the loss of remaining forest cover are discussed.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.3 s.131
• /
• pp.1-10
• /
• 2005

Tree-ring chronologies can be used to date historical buildings or furnitures by matching them with chronologies of living trees. Tree-ring dating gives a calendar year to each tree ring and produces the cutting dates of logs or woods. In this study, we intend to extend our tree-ring dating applications to Korean furnitures. As a case study, we examined two traditional furnitures, one cabinet 'Jang' and the other chest, 'Bandaji'. The cutting date of the cabinet woods was A.D. 1839. The date of the outmost ring in the chest was A.D. 1904. Due to no bark present, the cutting date of the chest was only estimated as $1930{\pm}10$ by 'sapwood rings' estimation method. Ring-width pattern of the latter one also indicated that the origin of the chest must be Kangwon province. This case study suggests that tree-ring dating would be a useful and accurate method to identify the critical dates for the chronicles of Korean traditional furnitures.

• Journal of the Korea Furniture Society
• /
• v.16 no.1
• /
• pp.17-23
• /
• 2005

European maple is famous for the optimum solid wood for making bridge which is the most important part in violin acoustics. This study was carried out to investigate the variation of main features, i. e. annual ring width and cutting direction of costly imported violin bridge blanks and to examine the effect of these features of the blanks on the vibrational characteristics of bridge blanks. Imported violin bridge blanks had somewhat large variation in major macroscopical and physical properties and there was little relationship between annual ring density and weight of maple blanks. Resonant frequency of violin bridge blanks had some positive correlation with weight, however, damping having negative relationship with frequency was seldom affected by any physical properties of the maple blanks. Deviation from the radial cutting of tail side(ray direction from top toward feet on the edge of bridge blank) lowered the resonant frequency. Consequently, weight and ray direction should be taken for the critical quality decisive factors(QDF) of incoming bridge blanks by not only inspectors also luthiers who tune the bridge by shaping and are responsible for the final timbre quality of this complicate instrument.

• Journal of the Korean Wood Science and Technology
• /
• v.18 no.4
• /
• pp.65-78
• /
• 1990

For the purpose of Improving the sounding boards for the conventional GAYAKUM, I was making approximately 202 specimens of radial board, 371 specimens of tangential board by cutting along the grain and the part of stem and 31 specimens of the disjointed traditional GAYAKUM made in Paulownia coreana. And it was conducted to measure specific gravity, dynamic Young's modulus, internal friction, resonant frequency, velosity of sound and width of annual ring by the method of the frexural vibration in a free-free bar in the audio frequency range. And it confirmed the juvenile wood by measuring wood fiber length of specimens. It was also conducted to investigate dynamic properties and moisture absorption by various heat-treatment and to test dynamic Young's modulus and internal friction for the disjointed conventional GAYAKUM. The results obtained were summarized as follow: 1. The Juvenile wood is located within about 7 annual rings from the pith in Paulownia coreana. 2. As increased with the specific gravity, the dynamic Young's modulus had more and more increased, but the internal friction had slightly decreased. 3. I think that radial board would be good for sounding board wood. because radial board is higher than tangential board in dynamic Young's mudulus and internal friction is lower than tangential board. 4. The value of mean dynamic Young's modulus on the conventional GAYAKUM, radial board and tangential board of 604 samples is $0.4283\pm0.037(\times10^{11}dyne/cm^2)$, $0.4316\pm(\times10^{11}dyne/cm^2)$ and $0.4234\pm0.112(\times10^{11}dyne/cm^2)$ respectively. The value of the radial board showed little higher than that of conventional GAYAKUM, but It had a similar tendency between conventional GAYAKUM and tangential board. 5. The annual ring width by four aspect is more narrow in north and west than that of others. 6. The values of specific gravity and dynamic Young's modulus in the mature wood showed higher than those of juvenile wood. 7. As the grain angle in the butt wood more increased to bark from pith, the dynamic Young's modulus were low. Then it was not good for sounding board. 8. It appeared that the heat-treatment for sounding board wood had a more effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature. 9. As increased with the temperature, the rate of moisture absorption of heat-treatment wood had decreased. In conclusion, I thought that the sounding board wood for GAYAKUM would had the most effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature using the radial board of mature wood.

• Journal of the Korea Furniture Society
• /
• v.20 no.4
• /
• pp.274-280
• /
• 2009

The purpose of this study was to identify the species of coffin woods excavated at Mundangdong in Gimcheon and to date this coffin by using tree-ring method. All coffin woods were identified as red pines, most possibly, Pinus densiflora S. et Z. Tree-ring dating provided absolute years of 3 among 19 coffins. Both I-9 and II-22 coffins were estimated to be made in the mid-seventeenth century, and I-65-1 in the mid-sixteenth century. Others possessed too few rings to be dated.

• Journal of the Korea Furniture Society
• /
• v.21 no.5
• /
• pp.424-431
• /
• 2010

Yungneung is the royal tomb of King Jangjo (the Crown Prince Sado, 1735~1762) and his wife, Hyegyeonggung-the Lady Hong (1735~1815). King Jangjo was the second son of the 21st King Yeongjo of the Joseon Dynasty. The tomb of King Jangjo was originally established at Yangju near Seoul in 1762 and moved to Whaseong near Suwon in 1789. We examined tree-ring (dendrochronological) dates of Jeongjagak, the ceremonial hall and Bigak, the tombstone house of Yungneung. We obtained tree-ring dates of 54 wood elements. The dates of bark rings were A.D. 1785, 1786, and 1787 with completed latewoods. These tree-ring dates were well matched with the historically recorded date of two buildings, A.D. 1789 when two or three year-storage after cutting logs was considered. The results indicated that the present buildings of Yungneung was built when the royal tomb of King Jangjo was moved from Yangju to Suwon. A historical record about the construction of Yungneung, 'Hyeonyungwon-eugye' confirmed the majority of woods was moved from 'Manrichang', an official storage office in Seoul through Han river and Yellow Sea to Suwon.