• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.9
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• pp.449-454
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• 2015

In this study, the effects of lock operations on the infiltration rates for the two window types sliding and lift sliding (LS) are investigated through experiment and simulation. The airtightness levels of the two window types-with locks both on and off-were measured according to the KS F 2292 Test method of airtightness that is used for windows and doors. The air-flow rates of both window types with the locks on for a pressure differential of 10 Pa are $1.98m^3/(m^2h)$ and $1.68m^3/(m^2h)$, respectively; with the locks off, the air-flow rates of the sliding and LS windows are $2.64m^3/(m^2h)$ and $5.83m^3/(m^2h)$, respectively, whereby the air-flow rates are 33% higher for sliding and 247% higher for LS. The air change per hour (ACH) was calculated using the ventilation-simulation software CONTAM. For the sliding window, the ACH changed from 0.45 to 0.57 when the lock was operated from on to off, representing an increase of 27%. For the LS window, the ACH changed from 0.29 to 0.81, showing an increase of 179%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.147-148
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• 2023

Steel doors, which are common in general buildings, do not seal the gap between the door and the floor, so drafts, noise, dust, and lights flow from the outside, and shielding devices are installed in various materials and methods, such as adding magnetic gate paper to the side of the door or installing a gasket under the door, but performance is limited. Accordingly, in order to fundamentally solve these problems, we researched and developed a double gap blocking device that can improve fire resistance and airtightness performance in steel doors. Unlike general products, the double gap blocking device has the advantage of maximizing airtight performance by forming an air layer in the center when the door is closed, as well as greatly improving the fire resistance performance, which is the basic performance of the fire door.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.6-12
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• 2000

We have developed a new split tee which can be used to effectively branch into a main gas steel pipelines without losing any gas pressure or having to shut down a line. The split tee has been designed considering the locations of branch connection to the pipelines. Therefore, we could keep the depth of buried pipelines which used to be the problem of the conventional split tees. Test results of the developed split tee showed that the performance of the tightness, hydraulic strength, sealing, welding, bending, and compatibility were excellent. The application of the split tee can provide the advantage of eliminating cost and time, and easy field pipeline coatings.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.331-336
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• 2003

The advanced spent fuel conditioning process(ACP) was proposed to reduce considerably the overall volume and radioactivity for effective management of the PWR spent fuel in respects on safety and economy. The ACP is under research and development, and have scheduled to perform hot test for demonstration of the ACP after several years. For hot test, hot cell facility of ${\alpha}{\gamma}$ type possess conservative safety is required essentially. A existing hot cell of ${\beta}{\gamma}$ type will be refurbished to minimize construction expenditures of hot cell facility. In this study, the design requirements are established, and the process detail work flow was analysed for the optimum arrangement to ensure effective process operation in hot cell. And also, the basic and detail design of hot cell facility and process and safety analysis was peformed to secure conservative safety of hot cell facility and process.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.1
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• pp.38-44
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• 2003

Performance demonstration with real flawed specimens has been strongly required for nondestructive evaluation of safety class components in nuclear power plant. Mechanical or thermal fatigue crack and intergranular stress corrosion cracking could be occured in the in-service nuclear power plant and mechanical fatigue crack was selected to study in this paper. Specimen was designed to produce mechanical fatigue flaw under tensile stress. The number of cycles and the level of stress were controlled to obtain the desired flaw roughness. After the accurate physical measurement of the flaw size and location, fracture surface was seal-welded in place to ensure the designed location and site. The remaining weld groove was then filled by using gas-tungsten are welding(GTAW) and flux-cored arc welding(FCAW). Results of radio graphic and ultrasonic testing showed that fatigue cracks were consistent with the designed size and location in the final specimens.

• The Journal of Engineering Geology
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• v.12 no.1
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• pp.35-51
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• 2002

This study aims to establish the methodology for design of an optimum water curtain system of the unlined underground oil storage cavern satisfying the requirements of hydrodynamic performance in a volcanic terrain of the south coastal area. For the optimum water curtain system in the storage facility, the general characteristics of groundwater flow system in the site are quantitatively described, i.e. distribution of hydraulic gradients, groundwater inflow rate into the storage caverns, and hydrogeologic influence area of the cavern. In this study, numerical models such as MODFLOW, FracMan/MAFIC and CONNECTFLOW are used for calculating the hydrogeological stability parameters. The design of a horizontal water curtain system requires considering the distance between water curtain and storage cavern, spacing of the water curtain boreholes, and injection pressure. From the numerical simulations at different scales, the optimum water curtain systems satisfying the containment criteria are obtained. The inflow rates into storage caverns estimated by a continuum model ranged from about 120 m$^3$/day during the operation stage to 130~140m$^3$/day during the construction stage, whereas the inflow rates by a fracture network model are 80~175m$^3$/day. The excavation works in the site will generate the excessive decline of groundwater level in a main fracture zone adjacent to the cavern. Therefore, the vertical water curtain system is necessary for sustaining the safe groundwater level in the fracture zone.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.832-835
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• 2009

폐기물의 감량화 및 자원화 기술 중 가장 대표적인 기술로 폐기물의 가스화 용융 기술을 들 수 있다. 폐기물 가스화 용융 기술은 폐기물 내의 탄소 및 수소 성분은 가스화 하여 CO, $H_2$가 주성분인 합성가스(synthesis gas, syngas)로 전환하고, 불연물은 용융하여 환경적으로 무해한 슬래그 또는 금속으로 회수하는 기술이다. 본 연구에서는 고발열량폐기물과 탈수슬러지 혼합가스화를 통하여 생산된 합성가스를 합성가스 압축기를 통하여 유용한 원료물질을 제조하는 공정인 수성가스 전환 반응(water gas shift reaction)과 가스화 반응기의 보조연료로 투입하기 위한 합성가스 압축, 이송 시스템의 운전 특성을 고찰하였다. 그 결과 고발열량폐기물과 탈수슬러지 혼합가스화에서 합성가스는 안정적으로 발생하였으며, 합성가스 압축, 이송시스템을 위한 정제설비에서의 분진제거는 99.07 %의 효율을 얻었고, 또한 합성가스 재순환 장치의 성능시험을 통하여 대기 중의 산소가 유입이 안 되는 기밀성을 확인하였다. 합성가스 압축, 이송 공급 유량 제어 실험 결과로는 합성가스 압축기 기동 시 합성가스 압축압력과 공급유량은 비례적으로 증감하는 것을 알 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.672-675
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• 2013

FTP(File Transfer Protocol)는 호스트에서 다른 호스트로 파일을 전송하기 위한 프로토콜로써, 데이터를 평문으로 전송하기 때문에 기밀성이 보장되지 않는다. 현재 보안 기능이 제공되는 FTP로 FTPS(FTP over SSL)가 있다. FTPS는 TLS(Transport Layer Security)와 SSL(Secure Socket Layer) 암호화 프로토콜 기반에서 동작하는 FTP 이다. 따라서 FTPS는 TLS와 SSL과 같은 추가적인 시스템이 반드시 필요한 단점이 있다. 본 논문에서는 추가적인 암호화 프로토콜 없이 FTP 내에서 보안 기능을 제공하는 Secured FTP를 제안하였다. 본 논문에서 제안한 Secured FTP 는 FTP 내에서 Diffie-Hellman 알고리즘을 이용하여 비밀 키를 교환하고 AES(Advanced Encryption Standard)-Counter 알고리즘을 이용하여 FTP 데이터를 암호화 및 복호화하도록 설계하였다. 본 논문에서 제안한 Secured FTP를 Linux 운영체제에서 구현하였고 시험을 통하여 비밀 키가 정상적으로 교환되고, FTP 데이터가 암호화되어 전송되는 것을 확인하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.4
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• pp.47-58
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• 2002

The pressure regulator has been developed as a pressure-control device of propellant tank in KSR-III. The pressurization system of KSR-III is a basic pressurization system composed of pressurant, He tank and propellant tank. The pressure-control regulator is the most important part of gas-pressurized feed system along with He tank, pyrovalve and He fill valve. The first model of the regulator is tested to satisfy in leakage, strength and basic performance. The second model is tested in the overall test of the KSR-III propulsion system using water. From the test result of the second model, we conclude that the capacity of valve(Cv) must be increased in real system. The third model is modified and tested in the overall test of KSR-III propulsion system using propellant. Finally, the pressure-control regulator is qualified from firing test.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.1-6
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• 2023

PE piping, which has advantages in terms of construction convenience and economy, is widely used for underground burial in the domestic urban gas field. These PE pipes use squeeze-off in many sites to block gas flow during maintenance and repair work. Squeeze-off refers to a method of compressing a PE pipe to block fluid flow, and damage may occur due to the nature of construction in which the pipe is deformed by physical force. In order to prevent damage to PE pipes due to squeeze-off, the main points to be reflected in the squeeze-off operation procedures such as proper compression range, use pressure, and diameter were derived through damage assessment and confidential test according to the compression rate. The compression experiment for PE pipe damage assessment was conducted while changing the compression rate (20%~40%), the pressure of use (2.8 kPa, 25 kPa, 70 kPa), and the pipe diameters (63 mm, 90 mm, 110 mm). As a result of damage assessment according to the compression rate, damage occurred in pipes with compression rates of 45%(110mm) and 73%(63mm), which are for analyzing the effect of excessive compression. In addition, the leakage test was conducted using Ar(argon) during the squeeze-off, and as a result of the experiment, leakage occurred under the conditions of 70kPa and 110mm of pipe. As a result of this study, it was confirmed that squeeze-off for airtightness should be carried out in pipes within a range not exceeding 25 kPa and 90 mm pipes, and the appropriate compression rate to prevent damage to PE pipes is 30%.