• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.40-45
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• 2008

This paper describes the effects of fly ash replacement on the water tightness of antiwashout underwater concrete, which replaced the cement with fly ash from 0% to 30%. The experimental work was performed to find out the depth of permeation of concrete specimens cast in air and cured in 23 $^{\circ}C$ tap water using an open center pressure type of water permeation tester. The results showed that the permeation depth values of antiwashout underwater concrete were deeper than normal concrete, but that an admixture using fly ash during antiwashout underwater concrete casting in air made it more watertight than normal concrete according to the water permeation testing. SEM observations of the specimens of fly ash antiwashout underwater concrete showed that it wasmore packed with structures because of the pozzolan reaction of the fly ash and cement.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.754-755
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• 2006

In order to develop the SUS304L housing by powder metallurgy for an optical device useful for the FTTH communication system, the optimum compacting pressure and sintering temperature were investigated using granulated powder as the material to satisfy high air-tightness and high laser-weldability. Then the laser-welding test of specimen made under the optimum condition was carried out to observe welding sputters.

• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.65-71
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• 2008

The purpose of this study is to investigate an airtightness of typical Korean detached houses with field measurements. Air leakage testings by means of blower door test in accordance with ASTM E79-8 were measured in 22 detached dwellings in Daejeon and Geumsan. The results showed that detached dwellings have an average airtightness with ACH50/20 (air chang per hour at a pressure difference of 50 Pa between inside outside) of 0.82 $hr^{-1}$ which is a higher range than for typical apartments and leakage class G by normalized leakage area of ASHRAE.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.782-789
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• 2020

The demand for the development of rolling stock technology to maintain the best performance in various climatic environments has increased to expand the overseas market of rolling stock. In this study, international and domestic standards that must be applied to build a harsh climatic environment test system were investigated and compared. The way of improvement for domestic standards is proposed. The wind velocities and temperatures are specified in the UIC, EN, and IEC standards for climatic wind tunnel, and EN 50125-1 provides the velocity test up to 180km/h, the largest wind speed. UIC and EN provide the lowest temperature of -45℃, and IEC 62498-1 provides the highest temperature 55℃. The solar radiation test was specified up to 1200W/m2 in the UIC, EN, and IEC. The IEC, EN, and KS R 9145 provide the water tightness standards, which are different from each other in water capacity, pressure, and methods. The snow test method was not well specified. KRTS-VE-Part 31 provides pressurization test methods. The airtightness standards for high-speed rolling stock are defined and regulated for internal pressure change rate in UIC 660 and 779-11. The domestic standard for the wind tunnel test was not well prepared, and the solar radiation test and snow test do not exist in Korea. Therefore, it is necessary to improve domestic standards to an international level for the climatic wind tunnel test of rolling stock.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.11 s.158
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• pp.1531-1537
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• 2006

This study was conducted to investigate the relation between clothing pressure and subjective sensation exerted by foundation. Nineteen females volunteered as subjects. Experimental foundations were brassiere with 70B, 70C, 75B and 75C size which were widely distributed in pilot test and two types of girdle of which size were 64, 70 and 76. Clothing pressure with an air pack system and subjective sensation were measured at 5 points in brassiere and 7 points in the girdle. As the result of this study, brassiere's band and girdle's waist line, of which clothing pressure are high, is needed to improve. Generally the more pressure makes the more tightness, however, in some regions more or less pressure can give comfort. The tightness rating may not only related to clothing pressure, but also related to factors such as body size, body fat, resilience of muscle and bone structure. Other subjective sensation such as tactile feeling, hot/wet feeling, etc. in addition to the study with consideration of these factors could be used in future research to evaluate the effectiveness of foundation.

• Journal of the Korean Society for Railway
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• v.5 no.2
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• pp.112-117
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• 2002

Reduction of noise level in the cabin of urban transit unit is an important issue to enhance the comfortability of passengers. It is made clear that a cause of increased noise level in cabin is the imperfect airtightness of entrance doors. In this study, the sliding-plug door system is developed to reduce the noise level of cabins by securing the airtightness of entrance door. The sliding-plug door system is composed of air-driven engine, swing arms, guide rails, guide rollers and locking devices. It is economical owing to using the previous door engine system. It is also adequate for the platform system of our subway station. It was tested to prove the reliability of system and was applied to standard urban transit unit. The effectiveness of noise reduction in cabin resulting form the sliding-plug door system was confirmed by test results.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.814-819
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• 2006

This research is on the design and introducing of integrated thermal performance of super energy saying building, called 3 Liter house which can be sustained with 3 liter oil(kerosene) per $yr.m^2$. 3 liter houses(Passive houses) offer extended living comfort with only 15 to 20% of the space heating demand of conventional new building. To achieve this purpose, the efficiency of building components is improved, such as walls, windows or ventilation system and the construction technology is improved, such as the prevention of thermal bridge and the air tightness. The fuel cell is used as alternative energy. Energy consumption of 3L house is 2.08 [liter/$yr.m^2$] in monitoring result of $2006/2/1{\sim}2/7$ and ACH50 is 0.67 in result of Blow Door Test, therefore 3L House is well- insulated and well- airtighted house.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.343-354
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• 2012

A electro-foaming fusion wrap fitting for polyethylene sewer pipe was built and foaming mechanism has been studied. A foaming sheet, supporting sheet and clamping band is assembled into a all-in-one structured electro-foaming fusion wrap fitting. To specify foaming and fusion of electro-foaming fusion wrap for PE sewer pipe, series of fusion tests were performed in various conditions. A parallel plate compression test up to 50 % of inner diameter deflection has been performed to check integrity of fusion quality and it was found that there were no visible signs of crack in wrapped area of fitting. Also air tightness test based on KS M 3511-2 has been performed to evaluate perfectness of wrap fusion quality and we found there were no pressure drop up to 10 times higher value than KS standard regulation.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.748-753
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• 2008

In modern buildings, the air-tightness and insulation for energy saving resulted in degradation of Indoor Air Quality(IAQ). It has brought out new diseases such as New Building Syndrome(NBS) and Sick Building Syndrome(SBS) to the tenants of such buildings. As a result, researches on the Dynamic Breathing Building(DBB) are being undertaken to minimize energy loss as well as to improve IAQ. DBB is a state-of-the-art technology to build channels inside the wall so that air migrates between indoor and outdoor, which improves insulation performance and IAQ. This study attempts to evaluate the improvement of DBB employed in real buildings. As analyzing tools, IAQ improvement and particle degradation while were evaluated while the required indoor ventilation rate was satisfied. DBB were installed in the twin test cells at Korea Institute of Energy Research(KIER). From the test, IAQ was compared with outdoor air base on the concentration of particle matter(PM10). As a results, the concentration of particle dust (PM10) within the breathing walls was reduced by 80% at 0.7 ACH, 67% at 2 ACH, 63% at 3 ACH respectively. As ACH is higher, Dnamic Isulation(DI) and normal wall permit more PM10 particles being infiltrated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.409-414
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• 2021

Tightness performance that blocks compartments is important for surface ships to achieve superior mission performance and survivability in combat environments. To meet the above requirements, airtightness of the structural elements and the appropriate strength to specific areas are checked during a test run after ship construction. In particular, air tests of compartments adjacent to the water surface are performed. In an air test, air is injected into the compartment up to the test pressure of the test memo. The pressure drop value is checked after 10 minutes to determine if the requirements of the corresponding area are satisfied. In summer, however, when the influence of the outside temperature is large, a phenomenon in which the internal pressure increases during the air test was identified. This phenomenon reduces the reliability of the test result. Therefore, a system was designed to compensate for temperature changes in the compartments through this study. The developed system calculates the amount of pressure change caused by a temperature change in the compartment and outputs a correction value. The pressure change was calculated using the ideal gas equation, reflecting the maintenance, increase, and decrease in temperature during the test process. A comparison of the calculated pressure correction value with the database of NIST REFPROP revealed a difference of 0.126% to a maximum of 0.253%.