• Animal Bioscience
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• v.34 no.6
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• pp.949-956
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• 2021

Objective: This study was focused on the estimation of parameters of Wood's model and description of the lactation curve using the cows which were lactated over 24 months on the first lactation. Methods: The database included 1,333 pure-bred dairy Simmental primiparous cows which lactated for 24 months (732 days). The initial dataset entering the procedure of assessment of parameters of Wood's function included 35,826 milk yield records. Milk yield was recorded throughout lactation, with the earliest record taken on day 6 and the latest on day 1,348 of lactation. This dataset was used for the assessment of parameters a, b, c of Wood's model using the non-linear statistical procedure. These parameters were estimated for different length of lactation. The assessed parameters were used for calculation of some characteristics of lactation curves. Results: The lowest value of a parameter (15.2317) of Wood's model of lactation curve was found out in lactations up to 305 days long, contrary to b and c parameters which were highest in those lactations (0.1029 and 0.0015, respectively). The maximum value of a parameter (17.4329) was found out in lactations up to 640 days long, unlike b and c parameters which were minimal in those lactations (0.0603 and 0.0010, respectively). Conclusion: It can be concluded that the parameters of Wood's model and the shape of lactation curve are changing with the growing number of milk yield records. Also, the assessed parameters revealed a significant milk production potential after 305 days of lactation.

• Journal of the Korea Furniture Society
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• v.24 no.3
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• pp.273-285
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• 2013

The bent wood technique has been used for making the bow, the musical instruments and the wagon wheel, The Winsor chair of England in 1730's was the first Lfurniture product by using this method. This method was spread out by Michael Thonet in Austria after the Industrial Evolution. Early making technique of Winsor chair was relatively easy, but Michael Thonet's bent chair was mass produced by the machine and launched the revolution in the industrial furniture. 20th-Century European furniture designers applied the method of layering and forming plywood to bent chairs, enhanced the function and conformability. The bent chair had a big impact on modern chair design. The bent chair has the formative beauty and convenience from the character of softness and colors of wooden materials and has been developed variously by furniture designers. This study is a new approach to use Dyed-Gathered Wood with various colors and patterns as a material of the bend wood. First, bent wood with the Dyed-Gathered Wood enhances a close texture of wooden material textures instead of coating the surface. Second, flexibility of the bent wood with the Dyed-Gathered Wood enables wood bending techniques. Lastly, the Dyed-Gathered Wood is made with relatively cheap woods, replaces expensive imported woods which cause product price rise. This method enables a material cost saving and a stable supply of material.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6959-6968
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• 2015

This study aims to update the supply-demand model of wood products(FOSMO-2013) and to forecast mid and long run supply and demand for each products. The subjects of the study include sawnwood, plywood, particle board, fiberboard(MDF), and pulp. The updated partial equilibrium model is composed of supply function, import demand function, demand function, price relation function. The long run outlooks of world prices of wood and wood products are imported from the results of Buongiorno(2012). This study also adopt Buongiorno's scenarios, which includes three scenarios of IPCC(A1B, A2, B2) and the other one with assumption of increasing fuelwood consumption of A1B scenario. The result says that the domestic productions of wood products are expecting to decrease while the imports of them increase even there are some differences among the products as well as scenarios.

• Journal of the Korean Wood Science and Technology
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• v.31 no.3
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• pp.24-29
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• 2003

This research was performed to investigate the diffusivity of borate rods in radiata pine (Pinus radiata D. Don) conditioned to 40 percent moisture content (MC). The deepest penetration of boron were observed in the longitudinal direction, followed by the radial and the tangential directions. The boron loading on the wood face adjacent to the borate rod tended to increase with diffusion time in all directions. To mathematically quantify boron diffusion, the diffusion coefficient of boron was determined using Boltzmann's transformation by assuming that it was a function of concentration only. The values of the longitudinal diffusion coefficients were between 1.3×10^-8 cm²/sec and 9.2×10^-8 cm²/sec. The radial diffusion coefficients were between 1.4×10^-8 cm²/sec and 9.5×10^-8 cm²/sec, and the tangential diffusion coefficients were between 5.2×10^-9 cm²/sec and 1.3×10^-8 cm²/sec. The differences of diffusion coefficients between the longitudinal direction and the radial direction were slight, although their concentration profiles were markedly different. This indicates that the amount of boron loading on the wood face adjacent the borate rod is one of the most important factor for boron penetration in wood with low MC.

• Journal of the Korean Wood Science and Technology
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• v.20 no.1
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• pp.72-78
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• 1992

지진과 관련있는 하중 속도에서 damping을 측정하기 위하여 합판과 목재 사이에 한개의 못을 사용한 접합에 대하여 조사 했다. 조사된 하중은 sine function 의 15Hz와 ASTM하중 속도 사이에서 행했다. Damping 율은 4Hz까지의 하중 속도에서는 증가를 보였으며 그후 15Hz 까지는 점진적으로 감소하였다. 강성은 높은 하중 범위에서 slip moduli가 지속적으로 증가 하였다. 낮은 하중 범위에서 2.5Hz까지 증가 하였으며 그후는 감소 하였다. Damping 율과 slip modulus는 하중 속도와 상관 관계가 낮은 반면 work capacity와 dissipated energy는 높은 상관 관계를 보았다.

• Journal of the Korean Wood Science and Technology
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• v.50 no.5
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• pp.365-374
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• 2022

Today, commercialized Hinoki cypress cubes are used for fragrance, humidification, and pillows in Korea. In this study, the sound absorption ability of Hinoki cypress (Chamaecyparis obtusa) cubes was examined. The three groups of Hinoki cypress cubes were prepared depending on their dimension (L: 9 × 9 × 9, M: 7 × 7 × 7, S: 4 × 4 × 4 mm). Their sound absorption coefficient was examined after filling 6, 8, 10, and 12 cm height in impedance tubes, respectively. Overall, the sound absorption ability depending on dimension was superior in the M group compared to the L and S groups. Also, as the filling height increased, the sound absorption capacity increased. In sum, noise reduction coefficients (NRC) of all Hinoki cypress cubes were 0.41-0.59. Thus, this research found that Hinoki cypress cubes have a sound-absorbing function.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.836-845
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• 2017

Gravimetric method is usually used to evaluate air-dry density, which is governing physical or mechanical properties of wood. Although it had high evaluation accuracy, the method is time consuming process. Thus, this study was conducted to estimate air-dry density of wood with high accuracy by using polychromatic X-ray and digital detector as alternative of gravimetric method. To quantify polychromatic X-ray projection for evaluating air-dry density, Lambert-Beer's law with the integral value of probability function was used. The integral value was used as weighting factor in the law, and it was determined by conducting simple test at various penetration depths and tube voltage. Mass attenuation coefficient (MAC) of wood also calculated by investigating polychromatic X-ray projection according to species, penetration depth and tube voltage. The species had not an effect on change of MAC. Finally, an air-dry density of wood was estimated by applying the integral value, MAC and Lambert-Beer's law to polychromatic X-ray projection. As an example, the relation of the integral value (${\alpha}$) according to penetration depth (t, cm) at tube voltage of 35 kV was ${\alpha}=-0.00091t{\times}0.0184$ while the regression of the MAC (${\mu}$, $cm^2/g$) was ${\mu}=0.5414{\exp}(-0.0734t)$. When calculation of root mean squared error (RMSE) was performed to check the estimation accuracy, RMSE at 35, 45 and 55 kV was 0.010, 0.013 and $0.009g/cm^3$, respectively. However, partial RMSE in relation to air-dry density was varied according to tube voltage. The partial RMSE below air-dry density of $0.41g/cm^3$ was $0.008g/cm^3$ when tube voltage of 35 kV was used. Meanwhile, the partial RMSE above air-dry density of $0.41g/cm^3$ decreased as tube voltage increased. It was conclude that the accuracy of estimation with polychromatic X-ray and digital detector was quite high if the integral value and MAC of wood were determined precisely or a condition of examination was chosen properly. It was seemed that the estimation of air-dry density by using polychromatic X-ray system can supplant the gravimetric method.

• Journal of the Korean Wood Science and Technology
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• v.50 no.2
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• pp.81-92
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• 2022

To analyze the relationship between climatic factors (mean monthly temperature and total precipitation) and tree-ring growths of Pinus densiflora S. et Z. from National Parks (according to region) of the Korea, 20 trees were sampled from 13 National Parks. Only trees that were successfully cross-dated were used for dendrochronological analysis, and at least 11 trees were included. The tree-ring chronology of Mt. Bukhan (covering the shortest period of 1917 - 2016 [100 years]) was assessed, as well as that of Mt. Seorak (covering the longest period of 1687 - 2017 [331 years]). After cross-dating, each ring width series was double-standardized by first fitting a logarithmic curve and then a 50-year cubic spline. The relationships between climate and tree-ring growth were calculated with response function analysis. The results show a significant positive correlation between a given year's February-March temperature, May precipitation levels, and tree-ring growth. It indicates that a higher temperature in early spring and precipitation before cambium activity are important for radial growths of Pinus densiflora in the Korea.

• Journal of the Korean Wood Science and Technology
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• v.33 no.1 s.129
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• pp.63-76
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• 2005

Wood-culture is new paradigm which is substituted for the cement culture, and the study of wood-culture should keep pace with not only the study of a engineering science but also a sociological study to form a theory system. The purpose of this study is to suggest the method of sociological approach of the wood culture which have not yet tried at home and abroad; in view of structural-functionalism, systemical-functionalism, conflict theory, social-change theory by analyzing cases in Korea. In view of structural-functionalism, social system consists of cognition system, institution system, life system and technology system. These sub-systems fulfill the function of what-should-be, reasonability, reality and development. In view of systemical-functionalism, according to the acknowledgment and spreading proccess of the wood usefulness, wood culture system consists of the individual system, organizational system and the social system. In view of conflict theory, the society which has the wood culture can be classified into three types. The one is society which the traditional wood culture is declining and the cement culture is spreading. The other one is society which the cement culture is declining and the traditional wood culture is spreading. Another is Finally the society which the two type balance with. In view of social-change theory, the society can be classified into three types. The one is society which the wood culture is proceeding to the cement culture. The other is society which the cement culture is proceeding to the wood culture. Another is society which the wood culture changes itself. Finally, from a view of changing level, the society can be classified into three types: the micro-change, the middle-level-change, and the macro-change. It's need to study wood culture systemically in view of engineering and sociological science. And then it will be possible to make 'wood culture theory system'.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.370-377
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• 2012

This study was conducted to investigate the color change of heat-treated wood made of Korean pine (Pinus koraiensis S. et Z.), and lodgepole pine (Pinus contorta Dougl). The wood samples were heat-treated at 9 different treatment combinations of temperature (170, 180, 200, 220, and $230^{\circ}C$), and time (90, 120, 180, 240, 270 min.) set up by a response surface method. Wood color was measured using a colorimeter, and the samples were installed for evaluating the resistance of termite in the field test sites set up in Jinju. The lightness decreased with the increase of treatment temperature and treatment time. The color differences were evaluated by the method of National Bureau of Standards (NBS), and response surface models to predict the color change were fitted as a function of treatment temperature and treatment time. The $R^2$ values of the fitted models of heat-treated Korean pine and lodgepole pines were 0.92, and 0.88, respectively, showing the potential way for the prediction of color changes. Severe damage was found from the samples in the field test site, which means that the manufactured heat-treated wood did not show the termite resistance enough for the outdoor use.