• Earthquakes and Structures
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• v.9 no.4
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• pp.767-788
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• 2015

A steel shear wall with double-tapered links and in-plane reference was developed for assisting the assessment of the structural condition of a building after an earthquake while maintaining the original role of the wall as a passive damper device. The double-tapered link subjected to in-plane shear deformation is designed to deform torsionally after the onset of local buckling and works as an indicator of the maximum shear deformation sustained by the shear wall during an earthquake. This paper first examines the effectiveness of double-tapered links in the assessment of the structural condition under various types of loading. A design procedure using a baseline incremental two-cycle loading protocol is verified numerically and experimentally. Meanwhile, in-plane reference links are introduced to double-tapered links and greatly enhance objectivity in the inspection of notable torsional deformation with the naked eye. Finally, a double-layer system, which consists of a layer with double-tapered links and a layer with rectangular links made of low-yield-point steel, is tested to demonstrate the feasibility of realizing both structural condition assessment and enhanced energy dissipation.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.238-241
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• 1989

Double wall corrugated paperboard box are almost used for package of agricultural and fishery products in Korea. Flaps of the double wall corrugated paperboard box are consist of the three linerboard and two corrugating medium. But these flaps which are not affected to the compression strength for storage and distribution results in the reasonable cost-up of the packed box. Compared the strengths and economical evaluations between double wall and single wall corrugated paperboard box results as follows. Compression strength of single wall box is higher 49.3% to 98.0% than that of the double wall corrugated paperboard box and its cost are down 5% to 8%. Effect of the cost down on the saving materials of flap and corrugating medium is 13.9%.

• Journal of the Korean Solar Energy Society
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• v.39 no.5
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• pp.65-78
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• 2019

In this study, we investigated the paraffin encapsulation using double-walled encapsulation technique. The first encapsulation used methyl methacrylic acid as the main component in acrylic polymer and the second encapsulation used melamine polymer. Particles size and distribution of the capsules were analyzed using scanning electron microscopy. In the first encapsulation, the stable capsules were obtained at 67% of phase change material ratio to methyl methacrylic acid monomer and the size of the capsule was from 0.2 to $0.3{\mu}m$. In the second encapsulation, the size of the capsules was almost the same with those capsules prepared in the first encapsulation. The particle size of single wall and double wall was about $0.3{\mu}m$. As a result of the encapsulation of paraffin using double-walled encapsulation technique, it was confirmed that the particle size was determined in the process of encapsulating using the acrylic polymer at the first wall material, and the physical and thermal stability of the capsules were imparted using melamine at the secondary wall material.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1217-1225
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• 2010

The possibility of a sodium-water reaction occurring in a conventional single-wall-tube steam generator in an SFR is a major problem. To improve the reliability of a steam generator, a double-wall-tube steam generator that can reduce the possibility of the occurrence of a sodium-water reaction is being developed. Current developments are focusing on improving the heat-transfer capability of a double-wall tube; further, the development of a leak-detection method to detect the occurrence of a sodium-water reaction during the reactor operation is also underway. In this study, new concepts, which will solve the above-mentioned problems, have been developed. Accordingly, a double-wall tube has been designed, fabricated, and mechanically tested for the purpose.

• Structural Engineering and Mechanics
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• v.27 no.4
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• pp.501-521
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• 2007

This study presents a model to better understand the shear behavior of reinforced concrete walls subjected to lateral load. The scope of the study is limited to squat walls with height to length ratios not exceeding two, deformed in a double-curvature shape. This study is based on limited knowledge of the shear behavior of low-rise shear walls subjected to double-curvature bending. In this study, the wall ultimate strength is defined as the smaller of flexural and shear strengths. The flexural strength is calculated using a strength-of-material analysis, and the shear strength is predicted according to the softened strut-and-tie model. The corresponding lateral deflection of the walls is estimated by superposition of its flexibility sources of bending, shear and slip. The calculated results of the proposed procedure correlate reasonably well with previously reported experimental results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.256-257
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• 2013

Roof and exterior wall of general formal buildings are designed and constructed through design focused exterior wall system and drainage and waterproof roof system. However, there are no classification of exterior wall and roof in freeform buildings and they are integrated as a surface of freeform buildings. Therefore it is necessary to develop the dry roof construction method using double skin roof system satisfying the design and function of the envelope. In this study, we have an effort to develop construction method of double-skin roof system using metal panel and PV.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.269-270
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• 2012

This study discussed the applicability of double layered bubble sheet(BS) to the concrete for retaining wall to verify the insulation effect as well as prevention of condensation. The BS was applied to the surface of retaining wall, which is contacted with ground. Temperature profile was monitored since placement of concrete. As expected, the application of BS helps the concrete keeping favorable heat insulating, preventing condensation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.29 no.4
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• pp.117-123
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• 1987

This study was conducted to develop an automatic insulation system to reduce the heat loss through the wall of greenhouses during the nighttime in winter. A double covered model vinyl house was constructed, and blowers were used to fill or remove styrene pellets automatically the inside of the double-wall of the double covered vinyl house. The effects of insulation of the double covered vinyl house insulated with the styrene pellets were analyzed by comparing with the single covered vinyl house. The results obtained from this study can be summarized as follows : 1. The optimum thickness of the double-wall of the double covered vinyl house was found to be 5 to 10 cm. 2.When the outside temperature varied in the range of -8.3 to -1.5$^{\circ}C$ during the nighttime, the inside temperature of the double covered vinyl house insulated with the styrene pellets showed 7.7 to 11.7$^{\circ}C$ and the inside temperature of the single covered vinyl house showed -5.8 to 2.3$^{\circ}C$. Therefore, the effects of insulation of the double covered vinyl house insulated with the styrene pellets were confirmed to be excellent. 3. Also, the excessive increase of the inside temperature in the vinyl house was prevented by the shading effect of the double covered vinyl house insulated with the styrene pellets during the daytime. 4. When the outside temperature varied in the range of 17.7 to 30.0$^{\circ}C$ during the daytime, it was possible to keep the inside temperature at 30${\pm}$4$^{\circ}C$ in the double covered vinyl house by operating the insulation system. 5. The transmissivity of the double covered vinyl house with the styrene pellets removed was 52.4 % on the average.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.21-32
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• 2022

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.225-226
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• 2023

This study examined the lateral deformation of double deck plate wall formworks against the lateral pressure of fresh concrete and then compared with the construction specification.