• 제목/요약/키워드: failure case

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Gurson Model과 Shear Failure Model을 이용한 파쇄튜브의 찢어짐 해석 (Analyses of Fracture Tube Tearing using Gurson Model and Shear Failure Model)

  • 양승용;권태수;최원목
    • 한국철도학회논문집
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    • 제11권3호
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    • pp.280-285
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    • 2008
  • Gurson model과 shear failure model 두 가지 파괴모델을 이용하여 노치인장시험과 초기 균열을 가지는 파쇄튜브의 압축거동을 유한요소법으로 해석하였다. Shear failure model의 파라미터 값은 노치인장시편의 시험 및 해석을 통하여 결정하였다. 항복강도와 파괴전단변형률 등의 파라미터 값을 정한 후, Gurson model과 shear failure model을 파쇄튜브의 해석에 적용하였다. Gurson model과 shear failure model이 인장시편에 대하여는 비슷한 파괴 거동을 보여주지만 파쇄튜브의 압축력과 균열 성장 속도에서는 다른 결과를 보임을 확인하였다. 즉, shear failure model에서는 Gurson model에 비하여 균열이 전파되기 위해 더 큰 압축력이 요구되었다. 이러한 현상은 shear failure model 이 재질의 손상 과정에 대한 고려를 포함하고 있지 않기 때문인 것으로 생각된다. 어느 모델이 튜브의 해석에 적당한 지를 실험을 통하여 검증할 필요가 있다.

강유역의 간흡충 감염양성자를 위한 사례관리 적용효과 (The Effects of Case Management for Clients with Clonorchiasis in Riverside Areas)

  • 김춘미;김희걸;전경자;김숙영
    • 지역사회간호학회지
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    • 제23권4호
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    • pp.427-437
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    • 2012
  • Purpose: In order to lower the infection rate and the reinfection rate of Clonorchiasis in high-risk areas, we performed and analyzed a case management on people with chlonorchisis. Methods: The data was collected from April 2010 to March 2011. A community health practitioner was selected as a case manager based on our training program. The intervention group had 58 participants with three months of case management and the control group had 144 participants handled with traditional methods. Results: the pre and post-test in the intervention group and the control group showed us improved knowledge of Clonorchiasis, attitudes and behavior toward eating freshwater fish. The results of post-test between the intervention group and the control group showed statistically significant differences in all categories, except a hand-washing category. However, one year after a case management, there was no significant difference in the failure rate of treatment. Conclusion: The case management was effective for people infected with Clornorchiasis near riverside areas; however, in order to lower the rates of reinfection and treatment failure, it is necessary to perform continuous monitoring and regular evaluations.

Failure analysis of prestressing steel wires

  • Toribio, J.;Valiente, A.
    • Steel and Composite Structures
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    • 제1권4호
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    • pp.411-426
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    • 2001
  • This paper treats the failure analysis of prestressing steel wires with different kinds of localised damage in the form of a surface defect (crack or notch) or as a mechanical action (transverse loads). From the microscopical point of view, the micromechanisms of fracture are shear dimples (associated with localised plasticity) in the case of the transverse loads and cleavage-like (related to a weakest-link fracture micromechanism) in the case of cracked wires. In the notched geometries the microscopic modes of fracture range from the ductile micro-void coalescence to the brittle cleavage, depending on the stress triaxiality in the vicinity of the notch tip. From the macroscopical point of view, fracture criteria are proposed as design criteria in damage tolerance analyses. The transverse load situation is solved by using an upper bound theorem of limit analysis in plasticity. The case of the cracked wire may be treated using fracture criteria in the framework of linear elastic fracture mechanics on the basis of a previous finite element computation of the stress intensity factor in the cracked cylinder. Notched geometries require the use of elastic-plastic fracture mechanics and numerical analysis of the stress-strain state at the failure situation. A fracture criterion is formulated on the basis of the critical value of the effective or equivalent stress in the Von Mises sense.

엔진케이스의 블레이드 컨테인먼트 (Blade Containment)

  • 김지수;박기훈;성옥석
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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    • pp.414-417
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    • 2011
  • 본 논문에서 Compressor 및 turbine 에서의 Blade failure등의 내부파손이 이를 둘러싸고 있는 케이스 내부에 머무르게 하는 엔진설계의 방법에 대한 이론 및 Simulation 등을 기술 하였다. 가장 무거운 부품 중에 하나인 케이스의 두께 최적화는, 항공기의 안정성뿐만 아니라 항공 효율을 높이기 위한 경량화의 목적을 위해서도 매우 중요한 설계목표 이다. 이러한 목적을 위하여 이론적 접근방법으로 에너지 밸런스 방법을 사용하였으며, 파손된 블레이드의 거동특성 및 영향성 평가를 위한 유한요소해석을 위하여 LS-DYNA가 사용 되어졌다.

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Safety and effectiveness of early cardiac rehabilitation in a stroke patient with heart failure and atrial fibrillation: a case report

  • Lee, Sang Cheol;Ko, Eun Jae;Lee, Ju Yeon;Hong, Ae Lee
    • Journal of Yeungnam Medical Science
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    • 제38권4호
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    • pp.361-365
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    • 2021
  • Stroke patients have reduced aerobic capacity. Therefore, intensive structured exercise programs are needed. We report the case of a patient with stroke and cardiac disease who underwent early inpatient cardiac rehabilitation (CR). A 38-year-old male patient with atrial fibrillation, heart failure, and cerebral infarction underwent a symptom-limited exercise tolerance test (ETT) without any problems on day 45 after admission. He completed a 2-week inpatient program and an 8-week home-based CR program. Follow-up ETT showed increased exercise capacity. The present case might be the first to report a safely performed CR program in a patient with stroke and cardiac comorbidity in Korea. Systematic guidance is needed for post-stroke patients to receive safe and effective CR for the secondary prevention of stroke and cardiovascular risk.

Parallel Venovenous and Venoarterial Extracorporeal Membrane Oxygenation for Respiratory Failure and Cardiac Dysfunction in a Patient with Coronavirus Disease 2019: A Case Report

  • Eun Seok Ka;June Lee;Seha Ahn;Yong Han Kim
    • Journal of Chest Surgery
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    • 제57권2호
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    • pp.225-229
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    • 2024
  • Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a lifesaving technique for patients experiencing respiratory failure. When VV ECMO fails to provide adequate support despite optimal settings, alternative strategies may be employed. One option is to add another venous cannula to increase venous drainage, while another is to insert an additional arterial return cannula to assist cardiac function. Alternatively, a separate ECMO circuit can be implemented to function in parallel with the existing circuit. We present a case in which the parallel ECMO method was used in a 63-year-old man with respiratory failure due to coronavirus disease 2019, combined with cardiac dysfunction. We installed an additional venoarterial ECMO circuit alongside the existing VV ECMO circuit and successfully weaned the patient from both types of ECMO. In this report, we share our experience and discuss this method.

구내고정원을 이용한 교정 치료중 miniscrew 탈락에 관한 연구 (A CLINICAL STUDY ON SKELETAL ANCHORAGE SYSTEM USING MINISCREW)

  • 우순섭;정순태;허영성;황경균;유임학;심광섭
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제29권2호
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    • pp.102-107
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    • 2003
  • At orthodontic treatment, we have made every effort to get rigid anchorage which is not stirred when teeth move. As a result, the miniscrew that is rigid anchorage was invented recently, and now it is used widely. Concerning the advantage of miniscrew, it is reduced dependence of extraoral anchorage and it shortens treatment time for rapid tooth movement. In contrast, the defect of miniscrew is falling off it resulted from increasing of the mobility. So the purpose of this research is to be of help to prognose clinical use of miniscrew, which is inserted for intraoral anchorage, by investigating and comparing the failure rate of miniscrew for loading time. This study researches the failure rate of miniscrew for teeth movement at the orthodontic treatment. The failure rate of miniscrew in mid course, after inserting 147 miniscrews in 51 patients, is 13%(20/147). It showed no statistically significant differences as compared man with woman, maxilla with mandible, double-head with uni-head miniscrew, and drilling and non-drilling before inserting the miniscrew. In comparison below twenties with over twenties and the times that we give load to miniscrew, it produced that the failure rate of miniscrew is 9.7% higher in the case of below the twenties than over the twenties. Also, the failure rate of loading immediately is 10.8% higher than loading after 7 days. According to using driver for the insertion of miniscrew, the failure rate of miniscrew is higher in the case of using machined driver than in the case of using hand driver when the level of significance is 95%. According to the research, we can suppose that the failure rate has no concern with using miniscrew on man or woman, maxilla or mandible, the shape of head, and drilling or non-drilling before insertion of miniscrew. Therefore, we can choose eclectic miniscrew as demands. In addition, we must notify the patient, below twenties, to be possibility of high failure rate. And It is strongly recommended to give load after $1{\sim}2$ weeks for healing of the insertion area.

정책실패의 반복과 관성에 관한 연구: 양양국제공항 사례를 중심으로 (Repetition and Inertia of Policy Failure -Focusing on the Case of Yangyang International Airport)

  • 허혁;최선미
    • 한국콘텐츠학회논문지
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    • 제18권12호
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    • pp.456-467
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    • 2018
  • 본 연구는 양양국제공항 사례를 중심으로 정책실패의 반복 원인에 대하여 분석하였다. 2002년 개항한 양양국제공항은 약 3,600억원을 들여 건설하였으나, 공항 이용 객수 확보 실패 및 활성화 실패로 지방공항의 대표적 실패사례로 거론되고 있다. 정책실패 이론에 따라 합리주의적 관점, 정치적 관점, 환경복잡성 관점에 따라 양양국제공항의 실패요인을 분석한 결과 첫째, 합리주의적 관점에서 양양공항은 이용객 확보와 지역경제 활성화라는 정책목표 달성에 실패하였으며, 이는 정치권의 압력에 의한 사업추진과 지리적 인프라 부족에 기인한 것으로 나타났다. 둘째, 정치의 흐름에서의 이해관계자들의 갈등 조정 실패 양상은 항공사와 공항 간 갈등과 저가항공인 플라이양양 허가 및 지원금에 대한 정부와 공항 간의 갈등 조정 실패로 볼 수 있다. 셋째, 환경복잡성 관점에서 양양국제공항은 주변 고속도로, 철도 노선 개통과 한한령으로 인한 중국인 관광객 급감이라는 환경변화에 적응 실패로 볼 수 있다. 즉, 양양국제공항은 정책계획단계에서부터 합리적인 분석에 의해 무산된 사업임에도 불구하고 정치적으로 선거결과에 따라 지리적 인프라가 부족한 지역에 건설되었으며 운영 과정에서 항공사 및 정부 간의 갈등 조정에 실패하였고, 주변 교통시설 확충과 외부 환경적 요인에 적응하지 못한 것으로 볼 수 있다. 본 연구를 통해, 대규모 국책사업의 경우 정책결정자의 무리한 사업 추진을 막을 수 있는 독립적 기구의 설치, 공항이나 철도와 같은 교통시설의 경우 주변 인프라 및 관련 사업과의 연계 및 고려를 통한 사업 추진, 이해관계자들 간의 갈등조정을 위한 협력적 거버넌스의 제도화 등을 제언하였다.

실패지식을 활용한 리더십 실패 특성 도출에 관한 연구 (A Study of the Trait of Leadership Failure Using Failure Knowledge)

  • 심형석;홍선관
    • 지식경영연구
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    • 제15권3호
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    • pp.1-12
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    • 2014
  • It is tried to draw the failure traits of leadership by extracting leadership parts from previous failure studies and including some parts which mention failure leadership among leadership-related books. All of 5 patterns are drawn through total 13 types of study data. From 'insensitive to change' and authoritarianism which is mentioned 8 times in such 13 studies, to 'interpersonal problem', which is mentioned five times, traits which are mentioned at least five times are selected. There are drawn 5 traits including ${\Delta}$ authoritarianism ${\Delta}insensitive$ to change ${\Delta}lack$ of executive ability ${\Delta}populism$ and ${\Delta}interpersonal$ problem. As being examined in these 5 types of failure traits, the failure of leadership is ultimately happened because of communication heading for the inside without any communication(exchange) to the outside. That is, it is understood that authoritarian leaders don't perceive change correctly but make a wrong communication (populism) or break down communication. Additionally, the executive ability is to perform actually one's idea and to be achieved through incessant communication with members. Compared with other various studies to draw failure factors, these leadership traits have something in common. In the previous researches conducted the study of general failure factors, ${\Delta}adherence$ to preexisting business and resistance to change ${\Delta}unfeasible$ expansion strategy ${\Delta}blind$ faith in successful technology and innovation and ${\Delta}insufficiency$ to grasp competitor(consumer) are pointed out as the failure factors. It is deemed that these are happened because organizational management is headed for the inside without any communication (exchange) to the external environments. Matters unfolded through this paper until now are an attempt to apply the failure knowledge to a leadership part which is an individual field in business administration. It is considered that this study will be complemented through additional case study or quantitative analysis in the future.

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