• Explosives and Blasting
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• v.27 no.2
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• pp.26-32
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• 2009

Although the number of blasting operations in urban area are growing, lesser attentions have been paid to the effects of impact load on nearby concrete structures. In this study, the properties of concrete were obtained by both the sonic velocity and Schmidt rebound tests, and the degree of damage in concrete material was evaluated by measuring the sonic velocity in sample before and after applying the impact load. The test results shows that the sonic velocity decreases with the increase of intensity of impact load, and the degree of damage in concrete samples is lower when the samples have higher strength and sonic velocity.

• Solar Energy
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• v.18 no.3
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• pp.63-69
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• 1998

The heat conduction and the water vapour diffusion flow through heat insulators between hygroscopical moist building materials were measured by means of the plate method. It was found that the heat transport increases with a moisture motion occuring in the temperature drop. On his basis of simplified assumptions, the increase in the thermal conductivity was calculated from the rate of diffusion flow per unit area, which generally resulted in values inferior to the measured values. The Increase in the heat transport due to water vapour diffusion measured at a large-scale wall specimen was inferior to the one measured by means of the plate method by using a comparable arrangement of layers. The overall heat transfer caused by moisture motion is not a characteristic value of the material, but a property of the whole wall structure

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.23-32
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• 2010

The purpose of this study is to quantify human energy budgets for different structures of outdoor spatial surfaces affecting thermal comfort, to analyze the impacts of tree shading on building energy savings, and to suggest desirable strategies of urban greenspace planning concerned. Concrete paving and grass spaces without tree shading and compacted-sand spaces with tree shading were selected to reflect archetypal compositional types for outdoor spatial materials. The study then estimated human energy budgets in static activity for the 3 space types. Major determinants of energy budgets were the presence of shading and also the albedo and temperature of base surfaces. The energy budgets for concrete paving and grass spaces without tree shading were $284\;W/m^2$ and $226\;W/m^2$, respectively, and these space types were considerably poor in thermal comfort. Therefore, it is desirable to construct outdoor resting spaces with evapotranspirational shade trees and natural materials for the base plane. Building energy savings from tree shading for the case of Daegu in the southern region were quantified using computer modeling programs and compared with a previous study for Chuncheon in the middle region. Shade trees planted to the west of a building were most effective for annual savings of heating and cooling energy. Plantings of shade trees in the south should be avoided, because they increased heating energy use with cooling energy savings low in both climate regions. A large shade tree in the west and east saved cooling energy by 1~2% across building types and regions. Based on previous studies and these results, some strategies including indicators for urban greenspace planning were suggested to improve thermal comfort of outdoor spaces and to save energy use in indoor spaces. These included thermal comfort in construction materials for outdoor spaces, building energy savings through shading, evapotranspiration and windspeed mitigation by greenspaces, and greenspace areas and volume for air-temperature reductions. In addition, this study explored the application of the strategies to greenspace-related regulations to ensure their effectiveness.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.2
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• pp.53-67
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• 2008

In this study, seismic control performance of friction dampers installed in a reinforced concrete shear wall-moment frame system, of which main lateral force resisting system is a shear wall, is investigated. Three configurations of friction dampers are investigated. One is a diagonal brace type reinforcing the shear wall directly, another is a diagonal brace type reinforcing the moment frame without the shear wall, and the other one is a vertical boundary element type installed at both ends of the shear wall. In addition, various levels of the total friction force and its distribution methods are examined. Time history analysis considering material nonlinearity is conducted for seismic loads increased by the enhanced design code compared to the initial design loads, and energy dissipation, lateral loads and structural member damages are analyzed. As a result, the shear wall-reinforcing diagonal brace type with the total friction force of 30 % of the reference friction force gives the best performance on the whole, and the distribution methods of the friction force do not have remarkable difference in effects. Also, concentrated installation in adjacent four stories shows just a little compromised control performance compared to the entire story installation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.523-528
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• 2011

Ok-Cheon catholic church has been changed 4 times since it's first construction in 1955. Prior three changes were small ones of windows, doors, roof finish etc. but the last alteration was the extension of it's plan from 一 shape to long cross shape and along with it the size, structure and form of it changed. This history of the church has not been recorded in drawing but only in text with indistinct features not documented. This study makes a new 2D CAD files using layers matched the changes and 3D digital models, these have not only present information but also change informations of the church. They are useful data for effective management, conservation restoration or possible reuse of it.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.8-14
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• 2019

In Korean traditional wooden architecture, joint performance varies with the material characteristics of timber, the form of joint, the precision of timber-trimming and the like. Case studies prove that the beam-to-column joint type has large influence on the degrees of deformation and spacing. This is not only true of single-story buildings, but also of large-scale multi-story buildings more apparently. Therefore, this study followed the process of examining to joint types, producing their specimens and testing their structural performance. As a consequence of structural test, the dovetail joint specimen showed the best outcomes of the maximum load and rigidity. Synthesizing the structural performances by respective forms of joints, the Doraegeoji dovetail joint specimen showed the higher performance, followed in order by the Doraegeoji mortise joint specimen and the Tongneoko dovetail joint specimen. The structural performance of a building varies with the characteristics by the shouldering forms of penetrating beams and with the joint types within the columns. This should be considered for the new construction or restoration of multi-story buildings, and be continuously researched henceforth.

• Explosives and Blasting
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• v.28 no.2
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• pp.59-68
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• 2010

Building demolition and blasting work in urban areas has a possibility which has an effect on the structural stability of nearby structures. In this study, the compressive strength and chemical composition of decrepit concrete materials were estimated by Schmidt rebound test and XRD phase analysis. The damage index of the concrete materials was calculated by measured P-wave velocities. It was revealed that the constituents of the concrete materials affect on the compressive strength. The damage index decreases with increasing compressive strength and decreasing impact energy.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.124-129
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• 2000

산업현장의 건물, 설비 등의 보온 및 단열을 위해 우레탄폼, 스치로폼 등 다양한 종류의 프라스틱류 단열재를 사용하고 있다. 이들은 착화 및 연소속도가 빠르고 연소시 유독가스를 다량 발생시켜 심각한 재산 및 인명피해를 초래하고 있다. 그러나, 이들 발포플라스틱들은 연소하기 쉬운 재료로서 급속한 화염전파, 높은 열방출율, 많은 양의 연기발생 등 화재의 위험성이 상대적으로 높다는 문제점을 안고 있다. (중략)

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.320-324
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• 2000

Nonlinear stress analysis of nuclear containment building is carried out using microscopic concrete material model. The present study mainly focuses on the evaluation of the ultimate pressure capacity of idealized containment building in nuclear power plant. For this purpose, an eight-node degenerated shell element it adopted and an imaginary opening in the apex of containment building is allowed in FE model. From numerical analysis, the adopted concrete material model performs well and has a good agreement with the result obtained by using ABAQUS. Finally, we propose the present study as a benchmark test for nonlinear analysis of containment building.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.4
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• pp.289-294
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• 2008

This experiment was conducted at college of Agriculture and Life Science in Chungnam National University from September, 2004 to June, 2007 in order to evaluate the mixture possibility between barley and rye in the area of Daejeon. Rye (cultivar; Koolgrazer) and barley (cultivar; Daeyeon Bori) were set for the experiment. The experiment was arranged in four treatments: R100 (rye 100%), R60 + B40(rye 60% + barley 40%), R50% + B50% (rye 50% + barley 50%), and R40% + B60% (rye 40% + barley 60%). The experiment was repeated three times in the randomized complete block. The average dry matter (DM) yield for three years of R100 weighed 9,282 kg and its DM yield was higher than any other DM yield. The higher the barley seed rates are, the lower the DM yield is (p<0.05). As the barley seed rates increased 40%, 50%, and 60% respectively, its vegetative percentage tended to increase 30%, 41%, and 47%, but the barley vegetative percentage against its seed rates did bring forth somewhat low results. Compared with R100, the contents of crude protein (CP) and in vitro dry matter digestibility (IVDMD) got higher as the barley seed rates became higher, while the contents of NDF, ADF, cellulose, and lignin were lower (p<0.05). Compared with R100, the yields of crude protein dry matter (CPDM) and digestible dry matter (DDM) showed lower in the any mixed barley (p<0.05). Thus, in case of using barley mixed with rye in the area of Daejeon, it seems to be quite difficult, unless the supply of high-productive barley variety is followed, to enhance the yields of DM, CPDM, and DDM.