• Title/Summary/Keyword: Cause of failure

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Toxicological Profiles of Poisonous, Edible, and Medicinal Mushrooms

  • Jo, Woo-Sik;Hossain, Md. Akil;Park, Seung-Chun
    • Mycobiology
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    • v.42 no.3
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    • pp.215-220
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    • 2014
  • Mushrooms are a recognized component of the human diet, with versatile medicinal properties. Some mushrooms are popular worldwide for their nutritional and therapeutic properties. However, some species are dangerous because they cause toxicity. There are many reports explaining the medicinal and/or toxic effects of these fungal species. Cases of serious human poisoning generally caused by the improper identification of toxic mushroom species are reported every year. Different substances responsible for the fatal signs and symptoms of mushroom toxicity have been identified from various poisonous mushrooms. Toxicity studies of mushroom species have demonstrated that mushroom poisoning can cause adverse effects such as liver failure, bradycardia, chest pain, seizures, gastroenteritis, intestinal fibrosis, renal failure, erythromelalgia, and rhabdomyolysis. Correct categorization and better understanding are essential for the safe and healthy consumption of mushrooms as functional foods as well as for their medicinal use.

Slope stability associated with construction (건설공사와 사면 안정성)

  • Baek, Yong;Kim, Gyo-Won;Koo, Ho-Bon
    • The Journal of Engineering Geology
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    • v.10 no.2
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    • pp.1-17
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    • 2000
  • In this study, 270 cut-slopes are investigated and statistical analyses are performed. More than 84% of unstable slopes are rock slopes or rock-soil mixed slopes, and 72% of the slopes have 10 to 30 meter in height. And in order to clarify the cause of failure, 3 slopes which have been failed are back-analysed by using the computer programs such as DIPS, UDEC and PCSTABL5M. A heavy rainfall during rainy season is a main cause of slope failure, and a blasting vibration during construction could also give a significant influence on the slope instability.

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Assessment of Internal Leak on RCS Pressure Boundary Valves (원자로냉각재계통 압력경계밸브 내부누설 평가)

  • Park, Jun-Hyun;Moonn, Ho-Rim;Jeong, Ill-Seok
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.322-327
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    • 2001
  • The internal leaks of RCS pressure boundary valves may cause thermal fatigue crack because of the TASCS in RCS branch line. After experienced unisolable piping failures in several PWR plants, many studies have peformed to understand these phenomena and various methods were applied to ensure the structural integrity of piping. In this paper, the cause of unisolable piping failures and the alternatives to prevent recurrence of failure were reviewed. Also, the severity of piping failure including susceptibility of valve leaks was evaluated for the Westinghouse 2-loop plant. The length of turbulent penetration on RHR inlet piping was measured and, thermal fluid analysis and fatigue analysis was performed for this piping. As a means of ensuring the structural integrity, temperature monitoring and specialized UT and other alternatives were compared for the further application.

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Thermal Stress Analysis of Brake Drum by Using Finite Element Analysis (유한요소법을 이용한 브레이크 드럼의 열응력 해석)

  • 박영철;박동성
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.3
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    • pp.77-84
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    • 2000
  • Nonlinear transient analysis is executed to obtain the temperature distribution, and to evaluate the thermal stress of brake drum by using FEA(finite element analysis). The result induces the reason why hair crack and the cause of drum failure occurs and the way how stress of drum decreases. The temperature of drum is in proportion to the drum thickness and it processes nonlinear changes at every points of drum. The higher bulk temperature raises, the more stress difference between inner surface and outer surface makes and the highest bulk temperature is at the corner section. It is necessary for the diminishment of the drum stress to make air flow, between drum and rim, move lively and use the materials of higher conductivity. The hair crack and the cause of drum failure seem to be started at the near corner section.

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Laparoscopic Surgery for Intussusception in Children (소아 장중첩증에 대한 복강경 수술의 경험)

  • Yoon, Doo Hwan;Nam, So-Hyun
    • Advances in pediatric surgery
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    • v.19 no.2
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    • pp.66-72
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    • 2013
  • Intussusception is common cause of intestinal obstruction in children. Most of intussusceptions can be treated with non-operative reduction using air or barium. However, about 10% patients need operative treatment due to failure of reduction, peritonitis, and recurrence after reduction. We introduce our experience of laparoscopic surgery for intussusception. From April 2010 to March 2013, we reviewed 57 children who diagnosed intussusception. Twelve patients underwent an operation. The cause of operation was 7 of failure of air reduction and 5 of recurrence after air reduction. Median age was 21.5 months (range: 5.0~57.7 months) and 11 children (91.7%) underwent successful laparoscopic reduction. Median operating time was 50 minutes (range: 30~20 minutes) and median hospital days was 4.5 days (range: 3~8 days). One patient had a leading point as a heterotopic pancreas and underwent bowel resection through conversion. There was neither intra-operative nor postoperative complication. Laparoscopic reduction for intussusception can bring an excellent cosmetic effect with high success rate.

Clinical Evaluation of Thoracoplasty (흉곽 성형술의 임상적 고찰)

  • 김형준
    • Journal of Chest Surgery
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    • v.25 no.1
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    • pp.96-104
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    • 1992
  • The 242 patients were operated due to chronic empyema in Hanyang University Hospital From Jan, 1983 to Aug, 1991, we operated 17 patients by modified.Schede`s thoracoplasty with myoplasty and we concluded to next scentences. 1. The age of patients were varied from 28 to 65[Average 39.1] and male preponderance was seen[more than 3 times]. 2. The preoperative cause of disease were tuberculosis in 14 patients[3 patients were associated with aspergillosis, and 1 patient was associated vrith actinomycosis], lung abscess in 2 patients, and haemophilia in 1 patient. 3. The Preoperative duration of empyema were varied from 1 month to 30 years[Average 49.8 month], and the duration from pulmonary resection to thoracoplasty were 1 month to 13.5 years[Average 55 month] except 3 patients, who were operated pneunectomy with thoracoplasty at the same time. 4. The total number of thoracoplasty were 19, because in 2 patients, we operated 2 steps, and we failed in 6 cases, so the success rate was 68.5%. 5. In failure analysis of 6 cases, the cause were obliteration failure in 3 cases, inadequete drainage in 1 case, and in the other 1 case was mixed type. 6. From 1990 to 1991, there were no death associated with operation and there were 1 failure, so the success rate was greatly improved. 7. The bronchopleural fistula or spontaneous rupture of trachea were seen in 12 cases, and the success rate was high in absent cases.

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Probabilistic Safety Assessment of Nuclear Power Plants Using Alpha Factor Method for Common Cause Failure (알파모수 공통원인고장 평가 기법을 활용한 원자력발전소 안전성 평가)

  • Hwang, Seok-Won
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.10 no.1
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    • pp.51-55
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    • 2014
  • Based on the results of Probabilistic Safety Assessment(PSA) for a Nuclear Power Plant (NPP), Common Cause Failure(CCF) events have been recognized as one of the main contributors to the risk. Also, the CCF data and estimation method used in domestic PSA models have been pointed out as an issue with respect to the quality. The existing method of MGL and non-staggered testing even widely used were considered conservative in estimating the safety and had a limited capability in uncertainty analyses. Therefore, this paper presents the CCF estimation using a new generic data source and Alpha factor method. The analyses showed that Alpha factor and staggered method are effective in estimating the CCF contribution and risk insights of reference plant. This method will be a common bases for the optimization of new design for the construction plants as well as for the updating of safety assessment on the operating nuclear power plants.

Comments on a Case Study on Engineering Failure Analysis of Link Chain

  • Yu, George Y.H.
    • Safety and Health at Work
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    • v.12 no.4
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    • pp.544-545
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    • 2021
  • The article by Tae-Gu Kim et al. conducted elastic FE modeling, which was inappropriate for fracture of elastic-plastic chain material (11.3% of elongation). FE analysis results and the findings in the fracto-graphic analysis did not tally but contradicted each other. The article identified "incorrect installation"/bending forces as the root cause while FE results of the chain under bending forces showed very low stresses at fracture locations but the highest stress in the middle of shank of the chain. The article's "step-like topographies indicating the fracture due to bending moment rather than uniaxial tension" lacked scientific support. The load value carried by each chain section under bending/incorrect installation was only half of that under tension, thus the article using same load value in FE simulation comparison for bending and tension was incorrect. The real cause of the chain fracture was likely improper checking the lifted load or/and using the wrong chain with much lower safety working load.

A Case Study on the Failure Cause Analysis of Power Cables (전력케이블 고장원인 분석에 관한 사례연구)

  • Hwang, Kwang-Su;Choi, Jong-Soo;Jung, Jong-Wook;Jung, Jin-Soo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2007.11a
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    • pp.345-347
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    • 2007
  • This paper describes a case study on the failure cause analysis of power cables and their fittings. For more accurate analysis, electrical and chemical analysis techniques were employed from the macrography stage for the exterior of the cables to the entire disassembly stage. As a result it was confirmed that the power cables failed due to improper fabrication by which electric field was concentrated at the deadend of a shrink tube on the cable.

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Impeller Failure and Pressure Pulsation of Boiler Main Feed Water Pump for Power Plant (발전소 주 급수 펌프의 임펠러 손상과 압력맥동 현상)

  • Kim, Yeon-Whan;Kim, Kye-Youn;Lee, Woo-Kwang;Lee, Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.368-373
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    • 2001
  • A major concern on high-energy centrifugal pump is the potential for interaction of two-phase flow phenomena with mechanical response of the pumping elements. The other concern is the pressure pulsations created from trailing edge of the impeller blade and flow separation and recirculation at partial load in centrifugal pumps. These interactions generating between rotor and casing cause dynamic pulsation on pump and exciting pipeline vibration. The higher severity responses, the more lead to failure of pump and system components. Finally, it cause severe axial vibration of single stage pump due to the hydraulic instability in flow condition below BEP.

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