• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.195-201
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• 2008

When reinforced concrete is subjected to high temperature as in fire, there is deterioration in its properties of particular importance are loss in compressive strength, cracking and spalling of concrete, destruction of the bond between the cement paste and the aggregates and the gradual deterioration of the hardend cement paste. Assessment of fire-damaged concrete usually starts with visual observation of color change, cracking and spalling of the surface. In this paper, it was reported the trends of research and practical use on the Explosive Spalling Properties of the High-Strength Concrete.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.310-315
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• 2008

The objective of design for a post flash-over fire is contain the fire and prevent structural collapse, as necessary to meet the performance requirements. In the post flash-over phase of a fire all of the combustible objects in the compartment are burning and the heat release rate is limited either by the fuel surface area or the available air supply. So for the PBD situations, the process of evaluation method for fire phenomena is very important. It is the aim of this study to investigate and analyze the evaluation method of structural fire resistance in Japan.

• Proceedings of the KSRS Conference
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• v.2
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• pp.567-569
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• 2006

Recently, the terrestrial laser scanner is considered as useful measurement equipment for acquiring a three-dimensional data. In this study, a terrestrial laser scanner which has +/- 2.5cm accuracy is examined whether the terrestrial laser scanner is reliable to present the tendency of landslide movement. The test area is covered by protection blocks, and they are being moved by landslide movement. Landslide movement was detected by measuring the movement of protection blocks. Totally three scenes of test area were acquired during 2004 and 2006. The three scenes of the protection blocks were registered in global coordinate system, then the landslide movement was investigated. The landslide movement detected in the three scenes was evaluated by comparing with landslide movement measured by a total station. Although the measurement accuracy of landslide using the terrestrial laser scanner was worse than the total station, the scanning data showed the tendency of landslide movement of the test area.

• Corrosion Science and Technology
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• v.16 no.5
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• pp.227-234
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• 2017

Reference electrodes are generally implemented for the purpose of monitoring the cathodic protection potentials of buried or immersed metallic structures. In the market, many types of reference electrodes are available for this purpose, such as saturated calomel, silver/silver chloride and copper/copper sulfate. These electrodes contain a porous ceramic junction plate situated in the cylindrical body bottom to permit ionic flux between the internal electrolyte (of the reference electrode) and the external electrolyte. In this work, the copper/copper sulfate reference electrode was modified by replacing the porous ceramic junction plate for a metallic platinum wire. The main purpose of this modification was to avoid the ion copper transport from coming from the inner reference electrode solution into the surrounding electrolyte, and to mitigate the copper plating on the coupon surfaces. Lab tests were performed in order to compare the performance of the two mentioned reference electrodes. We verified that the experimental errors associated with the measurements conducted with developed reference electrode would be negligible, as the platinum surface area exposed to the surrounding electrolyte and/or to the reference electrolyte are maintained as small as possible.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.305-309
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• 2001

Site-specific atmospheric dispersion characteristics have been analyzed. The northwest and the southwest wind prevail on nuclear sites of Korea. The annual isobaric surface averaged for twenty years around Korean peninsula shows that west wind prevails. The prevailing west wind is profitable in the viewpoint of radiation protection because three of four nuclear sites are located in the east side. Large scale field tracer experiments over nuclear sites have been conducted for the purpose of analyzing the atmospheric dispersion characteristics and validating a real-time atmospheric dispersion and dose assessment system FADAS. To analyze the site-specific atmospheric dispersion characteristics is essential for making effective countermeasures against a nuclear emergency.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.139-144
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• 2011

This paper presents a boundary element application to determine the optimal impressed current densities at defect position on the pipe line. In this protection paint, enough current must be impressed to lower the potential distribution on the metal surface to the critical values. The optimal impressed current densities are determined in order to minimize the power supply for protection. This inverse problem was formulated by employing the boundary element method. Since the system of linear equations obtained was ill-conditioned, including singular value decomposition, conjugate gradient method were applied and the accuracies of these estimation. Several numerical examples are presented to demonstrate the practical applicability of the proposed method.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.41-46
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• 2011

In the present work, a new freeze protection method has been proposed for a natural circulation system of solar water heater. Though electrothermal wire is popularly used for the purpose, there are freezing troubles by wire cut-off and excessive electric power consumption. In the experimental device, hot water in a storage tank was circulated by a small pump and used to heat the outdoor pipes if the cold water pipe surface temperature falls lower than a set point. As a result, It was observed that there was no hot water waste while the solar water heating system operated without freeze and burst.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.885-888
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• 2006

Nowaday, High strength concrete(HSC) has been mainly used in high rise building. HSC have superior property as well as improvement in durability compared with ordinary strength concrete. In spite of durability of HSC, explosive spalling in concrete front surface near the source of fire occurs serious problem in structural safety. Thus, this study is concerned with experimentally investigation fire resistance of the inorganic fire protection materials at high temperatures up to $800^{\circ}C$. From the test result, developed inorganic binder becomes general that with rising temperature the compressive strength of the material increases in tendency. Therefore, the results indicate that it is possible to fireproof panels, fire protection of materials, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.1
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• pp.52-56
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• 2006

This paper presents a cross-eye characteristics of multi-path wave scattering. Cross-eye method uses the phase differences of multi signals and is used fur electronic protection. When a signal is propagated from transmitter to receiver on the ground surface, direct wave and reflected wave signals are combined in front of the receiving antenna with different phases. To calculate and control the amplitude and phase of reflected signal, we have developed a cross eye electronic protection method for radar system and studied the variation of electric power density.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.8-14
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• 2018

Recently, serious problems occurred such as insecticide eggs, sanitary pads with carcinogens, radon(Rn) emitting beds in domestic. It had not been establishing the inspection system to evaluate safety and human harmfulness before occurring real accidents. This research was conducted to test preliminary experimental inspection for consideration of safety insensibility. The influence of corrosion of metals and plants was studied through aerosol type spraying of agricultural pesticide products coming into the market. These products contain primary three insecticide ingredients(Flufenoxuron, Etoxazole, Fipronil) in recent accidents. Visual examination, SEM-EDS and optical microscope were used for the analysis for corrosion effect. Results show that a lot of ingredients contain in the crop protection products, and various type of corrosion exist in the surface of metals and plants. Therefore, it is necessary to provide health warning and accurate range of use for crop protection products containing insecticide ingredients.