• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.533-540
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• 2012

Rubber laminated bearings with lead core are highly affected by changes in temperature because key materials which are rubber and lead have temperature dependencies. In this study, two full scale LRB(D800, S=5) are manufactured and temperature dependency tests on shear properties are accomplished. The shear properties at the 3rd cycle are used at $-10^{\circ}C$, $0^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$, $40^{\circ}C$ respectively. The double shear configuration, simultaneously testing two pieces, is applied for compression shear test in order to minimize the friction effects due to the test machine, described in ISO 22762-1:2010. Characteristic strength, post-yield stiffness, effective stiffness, equivalent damping ratio are estimated and presented coefficient due to the temperature changes.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.7-13
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• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.43-51
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• 2017

As per current seismic design codes, diagonally reinforced coupling beams are restricted to coupling beams having aspect ratio below 4. However, a grouped diagonally reinforcement detail makes distribution of steel bars in the beam much harder, furthermore it may result in poor construction quality. This paper describes the experimental results of concrete coupling beam reinforced with high-strength steel bars (SD500 & SD600 grades). In order to improve workability for fabricating coupling beams, a headed large diameter steel bar was used in this study. Two full-scale coupling beams were fabricated and tested with variables of reinforcement details and aspect ratio. To reflect real behavior characteristic of the beam coupling shear walls, a rigid steel frame system with linked joints was set on the reaction floor. As a test result, it was noted that cracking and yielding of reinforcement were initially progressed at the coupling beam-to-shear wall joint, and were progressed to the mid-span of the coupling beam, based on the steel strain and failure modes. It was found that the coupling beams have sufficient deformation capacity for drift ratio of shear wall corresponding to the design displacement in FEMA 450-1. In this study, the headed horizontal steel bar was also efficient for coupling beams to exhibit shear performance required by seismic design codes. For detailed design for coupling beam reinforced with high-strength steel, however, research about the effect of variable aspect ratios on the structural behavior of coupling beam is suggested.

• Korean Journal of Heritage: History & Science
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• v.55 no.3
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• pp.46-58
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• 2022

This study analyzed the documentation trend of garden components such as plants, infrastructure, unit facilities, and structures, based on 188 measurement drawings of 94 old houses in a report on the documentation of the national folklore cultural heritage. The findings are as follows. First, it was found that plants and structures continuously appeared as the subject of measurement drawings, while infrastructure was often omitted. It was confirmed that unit facilities, which are smaller than other components, were frequently excluded from the documentation subject as well due to frequent changes such as movement, loss, and expansion. Second, the level of expression in measurement drawings showed different aspects for each component. The unit facilities showed a large change over time with respect to the level of documentation, and the level of documentation was somewhat polarized, particularly toward the latter stage. This suggests that the level of documenting the drawings limited to specific facilities improved, but the overall level of drawings did not improve, such as a lack of diversification of expression techniques suitable for various unit facilities. On the other hand, it was confirmed that the level of documenting the drawings for plants, infrastructure and structures did not change to a significant degree, implying that no improvements were made to the expression of components. Third, as for the technique of detailed expression, in the case of plants, vegetation status was prepared without distinction of old or protected trees that have historical value. Above all, there was no record of the vegetation structure that could help grasp the vegetation landscape of the outer area. As for the infrastructure, there was no consistent expression technique to systematically convey topographic changes such as the height and slope of the land. In addition, since there was no subtype classification defined for unit facilities and structures, there was no subject or method of documentation. This study is meaningful in that it expanded the category of documentation, which has been concentrated on buildings in old houses, to gardens, and called attention to the need for documenting the gardens for the preservation and management of old houses as an integration of the building and outer area.

• Journal of the Korean Geotechnical Society
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• v.31 no.5
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• pp.5-21
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• 2015

An energy pile is a novel type of ground heat exchangers (GHEX's) which sets up heat exchange pipes inside a pile foundation, and allows to circulate a working fluid through the pipe for exchanging thermal energy with the surrounding ground stratum. Using existing foundation structure, the energy pile can function not only as a structural foundation but also as a GHEX. In this paper, six full-scale energy piles were constructed in a test bed with various configurations of the heat exchange pipe inside large-diameter cast-in-place piles, that is, three parallel U-type heat exchangers (5, 8 and 10 pairs), two coil type heat exchangers (with a 500 mm and 200 mm pitch), and one S-type heat exchanger. During constructing the energy piles, the constructability of each energy pile was evaluated with consideration of the installation time, the number of workers and any difficulty for installing. In order to evaluate the thermal performance of energy piles, the thermal performance tests were carried out by applying intermittent (8 hours operating-16 hours pause) artificial cooling operation to simulate a cooling load for commercial buildings. Through the thermal performance tests, the heat exchange rates of the six energy piles were evaluated in terms of the heat exchange amount normalized with the length of energy pile and/or the length of heat exchange pipe. Finally, the economic feasibility of energy pile was evaluated according to the various types of heat exchange pipe by calculating demanded expenses per 1 W/m based on the thermal performance test results along with the market value of heat exchange pipes and labor cost.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.97-97
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• 2011

현대사회에서 화재에 의한 물적 피해는 물론 인적피해가 현저하게 증가하고 있으며 희생자의 사망원인이 종래에는 화재시 발생한 열에 의한 화상을 중심으로 하는 소사였지만, 최근에는 화염보다 독성가스로 인하여 사망하는 경우가 많아졌고, 희생자는 거의 화상을 확인할 수 없거나 화상자이더라도 혈액 중에서 일산화탄소를 중심으로 한 유독가스가 확인되기 때문에 이들 유독가스의 흡입으로 인하여 행동불능상태 이후 열의 영향으로 사망한 것으로 추정되는 사례가 증가하는 추세이다. 따라서 대규모 건축물에 있어서는 화재발생시 유독가스가 건물 전체로 연소 확대되는 것을 방지하기 위하여 넓은 면적을 일정한 면적으로 구획하거나 계단실 등과 다른 부분 또는 층별 등으로 구획하고 있으며, 국내의 방화구획은 크게 다른 층으로 화재전파를 막기 위한 층간 방화구획, 연소면적을 제한하기 위한 면적별 방화구획, 다른 용도로 인한 화재 위험성 감소를 위해 용도별 방화구획으로 3가지를 법에서 채택하고 있다. 방화구획은 방화문 또는 자동방화셔터를 이용하거나, 내부구조의 바닥, 벽, 각종 방화문으로 구획할 것을 정하고 있다.(피난방화규칙 제14조) 본 연구에서는 철제방화셔터 대체용으로 직물방화셔터용의 실리카 소재를 이용하여 제직한 직물에 내열/차연 기능성 코팅의 공정 조건을 변화하여 최종 방화시험을 거치기 전 내열성 테스트중 하나인 불꽃열 통과량 실험을 실행하여 방화 직물의 내열성을 비교 분석하였다. 이러한 결과를 토대로 본 연구는 고내열/차연성 방화 제품 기술을 개발하는데 필요한 연구를 수행하는데 목적이 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.361-375
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• 2015

An energy pile is one of the novel ground heat exchangers (GHEX's) that is a economical alternative to the conventional closed-loop vertical GHEX. The combined system of both a structural foundation and a GHEX contains a heat exchange pipe inside the pile foundation and allows a working fluid circulating through the pipe, inducing heat exchange with the ground formation. In this paper, a group of energy piles equipped with parallel U-type (5, 8 and 10 pairs) heat exchange pipes was constructed in a test-bed by fabricating in large-diameter cast-in-place concrete piles. In addition, a closed-loop vertical GHEX with 30m depth was constructed nearby to conduct in-situ thermal response tests (TRTs) and to compare with the thermal performance of the cast-in-place energy piles. A series of thermal performance tests was carried out with application of an artificial cooling and heating load to evaluate the heat exchange rate of energy piles. The applicability of cast-in-place energy piles was evaluated by comparing the relative heat exchange efficiency and heat exchange rate with preceding studies. Finally, it is concluded that the cast-in-place energy piles constructed in the test-bed demonstrate effective and stable thermal performance compared with the other types of GHEX.

• Korean Journal of Remote Sensing
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• v.15 no.2
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• pp.175-181
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• 1999

A recurring eddy which located at the terminal end of the Korean East Warm Current was captured on ocean color and sea surface temperature imagery from satellite in spring and autumn. During late April, 1997 thermal infrared imagery from the NOAA AVHRR sensor and ocean color data from the Japanese ADEOS-I OCTS sensor, revealed this feature. The cold core had elevated chlorophyll concentrations, based on OCTS estimates, of greater than 3 mg/m$^3$ while the warmer surrounding waters had chlorophyll concentrations of 1 mg/m$^3$ or less. The elevated cholophyll accociated with this eddy has not been previously described. The eddy is also evident in SST images from autumn, but the SST in the core is warmer than in spring, and the warm jet flowing to the west of the eddy is also warmer is autumn compared to spring. A reccurring eddy and the high chlorophyll_a concentration area which surround around the eddy show on NOAA and SeaWiFS images in March 2, 1998. The eddy forms at the northern extent of the Korean East Warm Current as those waters collide with the cold, south-flowing Liman Current over a topographic shelf about 1500 m deep. This region of the eddy formation appears to have a strong connection with the dynamics of the western part of the polar front eddy field that dominates surface mesoscale structure in the central East (Japan) Sea. Interaction of the eddy with ARGOW tracked drifters, and evidence for its persistence are discussed.

• Ecology and Resilient Infrastructure
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• v.11 no.1
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• pp.11-22
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• 2024

A fishway is an artificial waterway or device used to resolve difficulties in the movement of fish in a river. Most existing fishways are made of concrete and emit toxic substances, which has a negative impact on the river environment. Accordingly, there is a need to develop fishway construction technology that is eco-friendly and can increase movement efficiency. The technology presented in this study is an integrated porous structure that combines the aggregate with a biopolymer material extracted from castor oil, a non-toxic material. It is a fishway construction technology using eco-friendly materials that can allow vegetation to grow on the surface. In this study, an eco-friendly fishway mixed with biopolymer and aggregate was built on a real scale and the fish movement efficiency was tested and analyzed. As a result of the experiment, a total of 201 fish of 14 species were released with tags inserted, and the detection rate of released fish was confirmed to be 82.6% on average. A total of 40 fish of 6 species were transported upstream through the fishway, and the average passage rate was confirmed to be 21.7%. As a result of checking the circadian migration pattern, it was found that all fish mainly migrate during the day. It was confirmed that there was no significant functional difference between a fishway using biopolymer and a concrete fishway. It is believed that a fishway using biopolymer can be used as a replacement for a concrete fishway.

• Journal of Environmental Impact Assessment
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• v.28 no.5
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• pp.492-506
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• 2019

Heavy metal contaminants in the shooting range are mostly present in a warhead circle or a metal fragment present as a particle, these fine metal particles are weathered for a long period of time is very likely that the surface is present as an oxide or carbon oxide. In particular, lead which is a representative contaminant in the shooting range soil, is present as more fine particles because it increases the softness and is stretched well. Therefore, by physical washing experiment, we conducted a degree analysis, concentration of heavy metals by cubic diameter, composition analysis of metallic substances, and assessment of applicability of gravity, magnetism and floating selection. The experimental results FESEM analysis and the measurement results lead to the micro-balance was confirmed thatthe weight goes outless than the soil ofthe same size in a thinly sliced and side-shaped structure according to the dull characteristics it was confirmed that the high specific gravity applicability. In addition, the remediation efficiency evaluation results using a hydrocyclone applied to this showed a cumulative remediation efficiency of 71%,twice 80%, 3 times 91%. On the other hand, magnetic sifting showed a low efficiency of 17%,floating selection -35mesh (0.5mm)target soil showed a relatively high efficiency to 39% -10mesh (2mm) efficiency was only 16%. The target treatment diameter of soil washing should be 2mm to 0.075mm, which is applied to the actual equipment by adding an additional input classification, which would require management as additional installation costs and processes are constructed. As a result, it is found that the soilremediation of shooting range can be separately according to the size of the warhead. The size is larger than the gravel diameter to most 5.56mm, so it is possible to select a specific gravity using a high gravity. However, the contaminants present in the metal fragments were found to be processed by separating using a hydrocyclone of the soil washing according to the weight is less than the soil of the same particle size in a thinly fragmented structure.