• 한국항공운항학회지
• /
• 제14권3호
• /
• pp.51-59
• /
• 2006

The air purity-sterilizer was developed and the CFD and experimental studies were carried out in order to investigate the performance of a air purity-sterilizer. Overhaul and exchange efficiency were increased by the modularization of the air purity-sterilizer. The good performance was validated by the hot-wire measurements and flow simulations in the room. Mean velocities at the exit of the air purity-sterilizer were 0.91, 1.62, 1.99, and 6.14 m/sec according to the fan mode. And the flow visualization of pured air was shown by using CFD flow simulation in the room of 24, 50 pyeong. The results show that the air purity-sterilizer has a high performance enough to produce air purity-sterilizer on a commercial scale.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.578-578
• /
• 2002

Thermal infrared imaging is a highly promising technology for condition monitoring and predictive maintenance of electronic, electrical and mechanical elements in nuclear power plants. However, conventional low-cost infrared imaging systems suffer from poor spatial resolution compared to commercial CCD cameras. This paper describes an approach to enhance inspection performances for calandria reactor area of Wolsung nuclear power plant through the technique of superimposing thermal infrared image into real CCD image. In the occurrence of thermal abnormalities on observation points and areas of calandria reactor area, unusual hot image taken from thermal infrared camera is mapped upon real CCD image. The performance of the technique has been evaluated in the experiment carried out at Wolsung nuclear power plant in the overhaul period. The results show that localizations of thermal abnormalities on calandria reactor face can be estimated accurately.

• Nuclear Engineering and Technology
• /
• 제48권6호
• /
• pp.1404-1411
• /
• 2016

Pipe wall thinning in the secondary piping system of a nuclear power plant is currently a major problem that typically affects the safety and reliability of the nuclear power plant directly. Regular in-service inspections are carried out to manage the piping system only during the overhaul. Online thickness monitoring is necessary to avoid abrupt breakage due to wall thinning. To this end, a transducer that can withstand a high-temperature environment and should be installed under the insulation layer. We propose a thin plate type of embedded ultrasonic transducer based on magnetostriction. The transducer was designed and fabricated to measure the thickness of a pipe under a high-temperature condition. A number of experimental results confirmed the validity of the present transducer.

• 한국정밀공학회지
• /
• 제15권9호
• /
• pp.25-32
• /
• 1998

The forced cooling system is designed to shorten the overhaul time of steam turbine, which is important in view of economic concern of utility companies, Forced cooling of the hot turbine is achieved by suction of air flow into the turbine after the turbine shuts down. The heat transfer process by suction of air flow can cause thermal stress due to the thermal gradients. In this paper, the analysis of heat transfer is performed to calculate the air flow rate. Based on the prediction of cyclic fatigue damage and the experience, the cooling equipment is designed for shortening the cooling time of steam turbine.

• International Journal of Reliability and Applications
• /
• 제5권2호
• /
• pp.47-57
• /
• 2004

The market for used products is becoming more competitive and dealers of used products use warranty to promote sales as well as to provide assurance to customers. Offering warranty results in additional costs associated with warranty servicing. This cost can be reduced through actions such as overhaul and upgrade that improves the reliability of the item. This is worthwhile only if the cost of improvement is less than the reduction in the warranty servicing cost. This paper deals with two models to decide on the reliability improvement strategies for used items sold with FRW policy.

• 항공우주시스템공학회지
• /
• 제14권6호
• /
• pp.36-43
• /
• 2020

The purpose of this study is to present the internationalization of South Korea's aircraft maintenance certificate for mutual recognition of aircraft maintenance license qualifications among various countries in preparation for an internationalization of the work conducted by the aviation industry. To achieve this objective, this study reviews the aircraft maintenance license training system and compares the standards for aircraft maintenance certification established by the Convention on International Civil Aviation with the standards for issuing domestic aircraft maintenance licenses. This comparative analysis shows that the domestic curriculum of aircraft maintenance licenses differs from international standards. As a result of this study, an improvement plan of the education content was proposed to enable the licensing qualifications of domestic aircraft maintenance licenses to be mutually recognized among different countries.

• Nuclear Engineering and Technology
• /
• 제54권10호
• /
• pp.3595-3603
• /
• 2022

Nuclear safety-class DCS is used for nuclear reactor protection function, which is one of the key facilities to ensure nuclear power plant safety, the maintenance for DCS to keep system in a high reliability is significant. In this paper, Nuclear safety-class DCS system developed by the Nuclear Power Institute of China is investigated, the model of reliability estimation considering nuclear power plant emergency trip control process is carried out using Markov transfer process. According to the System-Subgroup-Module hierarchical iteration calculation, the evolution curve of failure probability is established, and the preventive maintenance optimization strategy is constructed combining reliability numerical calculation and periodic overhaul interval of nuclear power plant, which could provide a quantitative basis for the maintenance decision of DCS system.

• 대순사상논총
• /
• 제25_2집
• /
• pp.137-176
• /
• 2015

This study intends to focus on feasible measures to take advantage of pilgrimage to inspire adherents of The Fellowship of Daesoonjinri with the ideology of Daesoon and to overhaul existing missionary work. This study addresses preceding researches with regard to pilgrimage as theoretical grounds to review what pilgrimage has been meant to be. Also, this study conducts the survey on the motif and preference of pilgrimage that are expected to affect pilgrim behaviors, and it includes the satisfaction with the pilgrimage as a parametric effect. The survey and analysis results say that the motif and preference of the pilgrimage are the leading variables that significantly correlate to the pilgrimage satisfaction. In addition, the pilgrimage satisfaction is not only a key factor that affects pilgrim behaviors but a parametric effect that strongly relates to the motif and preference of the pilgrimage. Conducted based on empirical analysis, this study offers a diversity of approaches to tourism program development with respect to pilgrimage: customized pilgrimage programs, unique storytelling about the holy places, content development with a range of topics and difficult levels, and evaluation and feedback systems for pilgrimage programs

• 한국컴퓨터정보학회:학술대회논문집
• /
• 한국컴퓨터정보학회 2020년도 제61차 동계학술대회논문집 28권1호
• /
• pp.273-274
• /
• 2020

본 논문에서는 부가가치가 높은 군용 장비류의 해외정비품을 국내정비로 전환하기 위한 절차 중 최종 성능평가 절차를 제안하였다. 기존의 절차는 해외정비품의 성능시험을 위한 정비능력 개발시 개발된 국산화 시험장비의 유효성 검증을 위한 명확한 절차가 마련되지 않아 소요군 혹은 실무자에 따라 최종성능평가의 기준이 다른 점이 발생하였다. 따라서 본 연구에서는 통일화된 절차를 연구하여 제안하였다. 제안한 이 절차는 통일된 기준 마련을 통해 해외도입 시험장비와 국산화된 시험장비의 상호 같음을 검증하여 해외로 나가는 정비대상품을 국내정비로 전환하였을 때 품질면에서 동일함을 보증하기위한 중요한 수단이 될 것이라 기대한다.

• 국제학술발표논문집
• /
• The 9th International Conference on Construction Engineering and Project Management
• /
• pp.694-701
• /
• 2022

This paper introduces a study of concrete structures with a broken tire and a flat tire as a complete overhaul. The materials used to make concrete in this study are solid aggregate, cement, sand, flat tire, broken wheel, drinking water, and Ordinary Portland Cement. A total of 6 main compounds were thrown into solid cylinders and replaced by 0% as a controller followed by 5% and 10%. The cylinder pressure test of the concrete is done by applying the same pressure to the cylinders until a failure occurs. The results of the pressure test show that by applying 5% aggregation the pressure decreases. In Crumb wheel joints, the compression force decreases constantly as the percentage change increases. Therefore, the crumb wheel is not recommended for use as a complete replacement due to its compressive church power.