• Journal of the Korean Institute of Gas
• /
• v.10 no.1 s.30
• /
• pp.32-37
• /
• 2006

Major components of refinery plants are exposed to various damage mechanisms depending on the operation condition, material selection and kinds of internal fluid. Inspection techniques and damage monitoring methods should be selected considering the damage mechanisms of the components. Hence, it is quite necessary to have an information system with a standardized database on the various damage mechanisms. In this study a damage information system with contents on the damage mechanisms included in API 571 code was developed. Concept of the screening table employed in USA and Japan was also adopted to identify the probable damage mechanisms from the information on operating temperature, internal fluid, metal used for the component and stress condition. This system can be used before the risk based inspection planning to identify key damage mechanisms involved.

• Journal of radiological science and technology
• /
• v.33 no.2
• /
• pp.93-96
• /
• 2010

This study evaluates usefulness of the developed assistant device by taking projection of patellofemoral joint in emergency patients who were doubt posterior cruciate ligament injury in knee joint. The subjects of experiment were patients who visited Eul-Ji University Hospital due to knee injury from January 2006 to December 2006. Seventeen patients, who took the Knee post stress view, Knee merchant view, Knee Seo's view to use assistant device and Knee MRI. To make assistant device of $170{\times}50{\times}70\;cm$, we evaluated its usefulness by measuring posterior dislocation of tibia. Seo's view is more accurate to make judgment of posterior cruciate ligament injury than original knee post stress view. Interval difference of posterior dislocation of original knee post stress view is $6.17{\pm}3.04$ and Seo's view is $8.74{\pm}4.47$. The results show injury of patellofemoral joint, vertical fracture of patella and posterior cruciate ligament injury by taking a projection using Seo's view. Therefore, it is useful to take projection earlier than talometer and MRI in emergency patients who were doubt posterior cruciate ligament injury in knee joint.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2009.01a
• /
• pp.467-472
• /
• 2009

최근 장애인에 대한 사회적 배려 및 관심이 높아지면서 장애인을 위한 각종 보조기구가 많이 개발되고 있다. 대부분의 청각, 시각, 정아 장애인들은 정자, 수화 등을 통해 타인과의 의사소통이 가능하며, 또한 이들을 위한 많은 보조기구가 개발되어 큰 도움을 받고 있지만 척수 손상 환자들을 위한 보조기구는 전무한 실정이다. 이에 본 논문에서는 척수 손상 환자를 위해 들숨, 날숨 기반으로 각종 기기(컴퓨터, 휠체어, 콘센트 등)들을 작동시키며, 또한 입력된 분자를 음성으로 출력할 수 있는 시스템을 설계하고 구현하여 척수 손상 환자들이 최소한의 도움으로 독립적인 활동이 가능하도록 하였다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05c
• /
• pp.311-316
• /
• 1996

제어봉이탈사고시의 핵연료봉 거동을 연구로에서의 반응도사고 모사실험 결과와 기존의 핵연료 손상기준을 비교하여 분석하였다. 반응도사고시 고연소도 핵연료의 손상은 주로 PCMI 기구로 발생하는데, 고연소도에서의 피복관의 부식 및 수소화 그리고 방사선조사에 의한 연성감소와 산화층 박리로 인한 수소화합물의 국부적인 집중화로 인한 피복관의 현저한 연성감소가 주요 원인이었다. 기존의 핵연료 손상 기준에서 DNB가 일어날때 핵연료 손상이 발생한다는 가정은 낮은 핵연료엔탈피에서 핵연료 손상이 일어나는 것과 동일함을 확인하였으며, 현재까지 발표된 실험자료와 핵연료손상기구의 분석을 통해 연소도에 따른 반응도사고시의 핵연료손상기준을 예비적으로 유도하였다. 핵연료손상은 낮은 연소도에는 DNB로 발생하고 고연소도에서는 PCMI로 발생할수 있기 때문에, 과도상태에서의 고연소도 핵연료의 건전성 유지를 위해서는 피복관 산화층의 박리로 인한 수소화합물의 집중화로 피복관의 연성이 감소되는 것을 방지할 필요가 있다.

• Composites Research
• /
• v.13 no.4
• /
• pp.1-10
• /
• 2000

SiC particulate reinforced metal matrix composites(MMCs) are emerging as candidate materials for the automobile and aerospace industries due to their significant increase in elastic modulus and strength compared to conventional metallic materials. However, in order to make successful application of MMCs, it is very important to understand micro-failure mechanism under cyclic loading because failure mechanism of MMC is dominated by accumulation of micro-failure due to applied loading. In this study, ultrasonic Lamb wave and acoustic emission(AE) have been used to monitor microscopic damage accumulation under cyclic loading for SiC particulate reinforced metal matrix composite(SiCp/A356). It was found that the change in velocity and attenuation of ultrasonic Lamb wave due to the increase of loading cycles could be characterized by three different stages corresponding to the microscopic fracture processes. The characteristic of AE signal at each stage was analyzed and discussed by comparing with the change of ultrasonic characteristic in MMCs.

• Composites Research
• /
• v.12 no.4
• /
• pp.62-70
• /
• 1999

It was well recognized that damages associated mainly with the aging of civil infrastructrues were one of very serious problems for assurance of safety and reliability. In recent, carbon fiber sheet(CFS) has been widely used for reinforcement and rehabitation of damaged concrete beam. However, the fundamental mechanism of load transfer and its load-resistant for carbon fiber sheet reinforced concrete are not fully understood. In this study, three point bend test has been carried out to understand the damage progress and micro-failure mechanism of CFS reinforced concretes. For these purposes, four kinds of specimens are used, that is, concrete, respectively. Acoustic Emission(AE) technique was used to evaluate the characteristics of damage progress and failure mechanism of specimens. In addititon, two-dimensional AE source location was also performed to monitor crack initiation and propagation processes for four types of these specimens.

• Journal of Chest Surgery
• /
• v.41 no.6
• /
• pp.803-806
• /
• 2008

The Nuss procedure has good cosmetic effects, but it could be cause of bleeding and organ injury during dissection of the anterior mediastinum. We have made an effort to overcome the defects of the traditional method through the anterior mediastinum, thus we developed a transilluminated introducer that made it safer and simpler to operate within a 1cm incision only. A total of 67 patients underwent the Nuss procedure using the transilluminated introducer. Thirty-six patients underwent the procedure with the transilluminated introducer only (age<4 years). Thirty-one patients had an additional thoracoscopy ($age{\geq}14\;years$). There were no major complications, such as massive bleeding or organ injury in the thoracic cavity during or after the Nuss procedure. Our findings demonstrated that the anterior mediastium could be dissected simply and safely by the use of a transilluminated introducer during the Nuss procedure without fatal major complications, such as bleeding and organ injury.

• Proceedings of the KWS Conference
• /
• 2005.06a
• /
• pp.71-72
• /
• 2005

• Journal of the Korean Society for Nondestructive Testing
• /
• v.30 no.4
• /
• pp.380-385
• /
• 2010

The integrity of components and piping of operating nuclear power plants has been identified by in-service inspection(ISI) requirements and activities commensurate with standards and codes such as KEPIC MI or ASME Code Section XI. However, the other various degradation mechanisms not considered during design stage of nuclear power plants have been checked by enhanced ISI. The requirements of enhanced ISI have been voluntarily developed by the industry itself or strickly issued by regulatory body. Even though the requirements were developed by the industry, they should be reviewed by regulatory body for their application in nuclear power plants. The enhanced ISI activities and requirements of non-destructive examination(NDE) which reflect the degradation issues in nuclear power industry will be primarily discussed in this paper.

• Journal of the KSME
• /
• v.35 no.6
• /
• pp.468-480
• /
• 1995

항공기구조는 항상 피로하중에 노출되어 있고 조류충돌과 같은 불시의 상황에 의해 손상을 입을 가능성을 가지고 있어서 이에 대한 대비책을 마련하지 않으면 인명과 재산상에 막대한 손실을 초래할 가능성이 있다. 따라서 항공기가 개발되는 초기의 설계단계부터 항공기의 안전성확보가 중요하며, 이를 위해서는 적절한 피로수명예측과 손상허용설계를 해나아가는 것이 중요하며, 그 내용을 정리하면 다음과 같다. (1) 항상 손상의 가능성을 인정하고, 이 손상이 존재하는 경우에도 항공기의 안전이 보장 되도록 설계한다. (2) 손상이 발생하면 쉽게 발견되도록 설계한다. (3) 한 부재의 손상이 전 구조물의 파괴로 이루어지지 않도록 다중하중 경로로 설계한다. (4) 손상의 가능성이 있는 부품은 특별관리한다. (5) 안전균열성장 및 잔류강도 요구조건이 충족되도록 검사계획을 수립하며, 이 검사계획에 따라 검사를 수행한다.