• Transactions of Materials Processing
• /
• v.28 no.5
• /
• pp.266-274
• /
• 2019

Metal sealing is used to connecting the parts between valves and fuel pipes for a FCEV which utilizes hydrogen gas of 700 bar. Instead of general carbon steel, stainless steel is the primary material used to manufacture fuel pipes due to hydrogen embrittlement. The shape of deformation between metals is an important factor on the air-tightness of the metal to metal contact. Since the stainless steel pipe is hardened using the plastic forming during the tip shaping stage, this work hardening could have an effect on the deformed shape and characteristics of contact surfaces in fastening of pipes. In this paper, the deformation history of the pipe model was considered in order to analyze the hydrogen-tightness on the metal sealing part. The contact distance and the forward displacement for fastening were compared using experimental results and the simulation results. The simulation of the effect of material change on the fitting body demonstrated that the hardness or the strength of the formed tip of the pipe was designed to a proper valued level since the characteristics of the contact surface was exhibited better when the strength of the pipe was lower than that of the fitting body.

• Journal of the Korean Ceramic Society
• /
• v.27 no.7
• /
• pp.833-840
• /
• 1990

For the development of multi-functional materials which has water reducing power, air entraining power and waterproofing power as well as blending additive in cement mortar the coal ash was modified with asphalt-stearic acid or asphalt-boiled oil mixtures by mechanical treatment. And the physical properties of cement mortar blended with modified coal ashes were compared with those of the water-tightness-cement mortar and the ordinary-portland-cement mortar added with AE.water reducing agent. The mortar of coalash-blend-cement modified with asphalt-stearic mixture was increased acid about 20% in initial strengths and decreased about 20% in water absorption ratio than those of ordinary coalash-blend-cement. The mortar of coalash-blend-cement modified with asphalt-bolied oil mixture was similar to the cement mortar added with AE.water reducing agent in water reduction ratio, air entraining conents and the initial strengths, also was similar to the water-tightness-cement mortar in water absorption and water permeability ratios.

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

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.10a
• /
• pp.296-297
• /
• 2013

We have investigated correlation between airtightness measured by blower door and airborne sound insulation measured in the upper and lower units. We consist of two cases : all windows sealed(CASE 1) and not sealed(CASE 2). As a result, CASE 1 is tighter than CASE 2 in airtightness, but CASE 1 is lower than CASE 2 in sound level difference. This is because of big wind on measuring CASE 1. Thus we are going to measure them at another fields considering this factor. Finally we ought to find out the correlation between airtightness and sound insulation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.2
• /
• pp.63-68
• /
• 2016

To study the effect of installation and the shapes of filling pieces used for windows on the infiltration rate, infiltration tests were performed with two types of sliding windows and two shapes for the filling pieces. Infiltration occurred most at the top and bottom parts of the center location where two windows overlap, indicating the necessity of a filling piece to be installed at these locations. Infiltration velocity is proportional to the square root of the pressure difference, complying well with the theoretical correlation. Infiltration is reduced about 50% by the filling piece installation. This study shows that filling pieces are essential and their shapes play significant roles in reducing the infiltration of windows.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.1445-1446
• /
• 2010

• Tunnel and Underground Space
• /
• v.19 no.2
• /
• pp.77-85
• /
• 2009

Flexible and lined segment air-tight tunnelling technology for Compressed Air Energy Storage-Gas Turbine(CAES-G/T) power generation was introduced. The distinguished characteristics of the air-tight tunnel system can be summarized by two facts. One is that the high inner pressure due to compressed air is sustained by surrounding rock mass with allowing sufficient displacement of lining segment. The other is that the air-tightness of storage tunnel was enhanced by adopting a specially designed rubber sheet. The flexible lined air-tight underground tunnel can be constructed at a comparatively shallow depth and near urban area so that the locally distributed CAES-G/T power generation can be accomplished. In addition, this air-tight tunnelling technology can be applied to a variety of energy underground storage tunnels such as Compressed Natural Gas(CNG), Liquifed Petroleum Gas(LPG), DeMethyl Ether(DME) etc.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2356-2361
• /
• 2003

Proteome research in the medical field is expected to accelerate the understanding of disease mechanism, and to create new diagnostic concept. For protein profiling, this paper proposes a new methodology named CPDIB (Crude Protein Direct Blotting). In the CPDIB procedure, crude protein sample is directly immobilized on a membrane and the expression of protein molecules in the sample are analyzed quantitatively by using a special device called ImmobiChip, where the membrane is used as a field of the immune reaction. The over-all structure of the ImmobiChip is based on the conventional Slot blot device. Mechanical improvement in the air-tightness of the case holding the membrane realizes the direct blotting and results in high performance of stability in the immune reaction. In the measurement of multiple proteins, a dispensing robot is used for increasing the efficiency of handling of liquid. Cooperation of the dispensing robot with the ImmobiChip for immobilizing proteins realizes automated and stable performance of the CPDIB procedure. This paper shows the evaluation of the air-tightness of the ImmobiChip, the ability of analyzing proteins using the CPDIB procedure and the performance of the automated equipment.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.102-107
• /
• 2009

Window system is an essential component for lighting, ventilation and thermal environment in buildings. Moreover, as balcony extension in apartment houses become legalized, the performance requirements of window systems in balcony space are getting complicated. However, at this moment, five properties of the windows are used to represent the performance aspects of the system, including wind resistance, air tightness, water tightness, sound insulation, thermal resistance. And such single properties are not capable to express the performance of a space with the window systems in terms of performance concept. A performance analysis with wholistic approach is required to see the effect of the window system in built environment. Thus, performance-based approach should be established, which will be able to evaluate the goal/function and comfort of occupants/owners. As the first step to develop the performance indicator for the window systme for balcony space, this study conducts a survey to find the required performance aspects. A complete set of performance-based indicators will be developed with verification methods in the later stage of research.

• International Journal of High-Rise Buildings
• /
• v.1 no.2
• /
• pp.99-105
• /
• 2012

The higher the building height and the larger the temperature difference between the outdoor and indoor space, the more remarkable is the draft driven by the stack effect in high-rise buildings. Moreover, the stack effect can bring about the deterioration of habitability and the degradation of the performance of the indoor control system in high-rise buildings. In this study, as a measure to attenuate the stack effect, the E/V shaft cooling method was proposed and its performance was compared with the conventional stack effect control method for strengthening the air-tightness of the building using a numerical simulation method. The total decreasing ratios on the stack effect in a building were compared, and the probabilities of the secondary problems were analyzed. The results show that the E/V shaft cooling is very effective to decrease the stack effect in a high-rise building in terms of the reduction performance and application. Moreover, this method does not cause secondary problems, such as stack pressure transition to other walls, unlike the conventional stack effect mitigation method.