• Title/Summary/Keyword: Cause of failure

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Non-destructive Leakage Location Analysis Method in Substrate Behavior Response Testing of Waterproofing Membrane Systems using Thermal Emission Camera

  • Oh, Kyu-Hwan;Jiang, Bo;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.11a
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    • pp.47-48
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    • 2017
  • The substrate behavior response testing outlined in KS F 2622 evaluates the leakage cause of waterproofing membrane systems when subjected to the concrete joint load behaviors by removing the waterproofing layer after testing, relying mostly on visual observation and subjective analysis. A non-destructive leakage cause and failure type analysis method is proposed currently in this study by the means of detecting leakage paths using thermal emission imaging systems. Test specimens are placed in varying temperature conditions after the concrete joint movement testing and are scanned using the thermal emission camera to determine the location and dimension of the adhesion failure/leakage path beneath the waterproofing membranes.

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CURRENT ISSUES ON PRA REGARDING SEISMIC AND TSUNAMI EVENTS AT MULTI UNITS AND SITES BASED ON LESSONS LEARNED FROM TOHOKU EARTHQUAKE/TSUNAMI

  • Ebisawa, Katsumi;Fujita, Masatoshi;Iwabuchi, Yoko;Sugino, Hideharu
    • Nuclear Engineering and Technology
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    • v.44 no.5
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    • pp.437-452
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    • 2012
  • The Tohoku earthquake (Mw9.0) occurred on March 11, 2011 and caused a large tsunami. The Fukushima Dai-ichi NPP (F1-NPP) were overwhelmed by the tsunami and core damage occurred. This paper describes the overview of F1-NPP accident and the usability of tsunami PRA at Tohoku earthquake. The paper makes reference to the following current issues: influence on seismic hazard of gigantic aftershocks and triggered earthquakes, concepts for evaluating core damage frequency considering common cause failure with correlation coefficient against seismic event at multi units and sites, and concepts of "seismic-tsunami PSA" considering a combination of seismic motion and tsunami effects.

Clinical study on Renal Replacement Therapy for Acute Renal Failure following Cardiopulmonary Bypass (체외순환후 급성 심부전에 대한 신대체요법의 임삼적 검토)

  • 서경필
    • Journal of Chest Surgery
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    • v.25 no.3
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    • pp.232-239
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    • 1992
  • Acute renal failure is a well known serious complication following open heart surgery and is associated with a significant increase in morbidity and mortality rate. From 1984 to 1990, 33 patients who had acute renal failure following cardiopulmonary bypass received renal replacement therapy. PD[Peritonial dialysis] was employed in 11 patients and CAVH[continous arteriovenous hemofiltration] was employed in 22 patients. Their age ranged from 3 months to 64 years[mean 25.5$\pm$7.8 years]. The disease entities included congenital cardiac anomaly in 18, valvular heart disease in 15 and aorta disease in 2 cases. Low cardiac output was thought as a primary cause of ARF except two redo valve cases who showed severe Aemolysis k depressed renal function preoperatively. Mean serum BUN and creatinine level at the onset renal replacement therapy were 65$\pm$8 mg/dl and 3.5$\pm$0.4 mg/dl respectively, declining only after reaching peak level 7&10 days following the onset of therapy. Overall hospital mortality was 72.7%[24/33]; 81%[9/11] in PD group and 68.2% [15/22] in CAVH group respectively. The primary cause of death was low cardiac output & hemodynamic depression in all the cases. The fatal complications included multiorgan failure in 7, disseminated intravascular coagulation and sepsis in 6, neurologic damage in 4 and mediastinitis in 3 cases. No measurable differences were observed between CAVH and PD group upon consequence of acute renal failure and disease per se. The age at operation, BUN/Cr level at the onset of bypass and highest BUN/Cr level and the consequence of low output status were regarded as important risk factors, determining outcome of ARF and success of renal replacement therapy. Thus, we concluded that althoght the prognosis is largely determined by severity of low cardiac output status and other organ complication, early institution of renal replacement therapy with other intensive supportive measures could improve salvage rate in established ARF patients following CPB.

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A Study on the Failure Cause of Large Scale Rock Slope in Limestone Quarries (석회석 광산에서 발생한 대규모 암반사면의 붕괴원인 분석에 관한 연구)

  • Lee, Sang-Eun;Kim, Hak-Sung;Jang, Yoon-Ho
    • Tunnel and Underground Space
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    • v.24 no.4
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    • pp.255-274
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    • 2014
  • The target of this study is large scale rock slope collapsed by around 7 pm on August, 2012, which is located at ${\bigcirc}{\bigcirc}$ limestone quarries of Gangneung city, Gangwondo. The slope prior to the collapse is formed as the height of about 200 m and the average inclination of $45^{\circ}$. The estimated amount of the collapse is about $1,500,000m^3$ with respect to the slope after the collapse. Geotechnical and field investigations such as boring, geophysical prospecting, surface geological survey, geological lineaments, borehole imaging, metric 3D imaging, experimental and field test, mining work by year, and daily rainfall were performed to find the cause of rock slope failure. Various analyzes using slope mass rating, stereonet projection, limit equilibrium method, continuum and non-continuum model were conducted to check of the stability of the slope. It is expected that the cause of slope failure from the results of various analysis and survey is due to the combined factors such as topography, rainfall, rock type and quality, discontinuities, geo-structural characteristics as the limestone cavity and fault zones, but the failure of slope in case of the analysis without the limestone cavity is not occurred. Safe factor of 0.66 was obtained from continuum analysis of the slope considering the limestone cavity, so the ultimate causes of slope failure is considered to be due to the influence of limestone cavity developed along fault zone.

A Cause Analysis of the Construction Incident Using Causal Loop Diagram : Safety Culture Perspective (인과지도를 활용한 건설 안전사고 원인 분석 : 안전문화 관점)

  • Choi, Yun Gil;Cho, Keun Tae
    • Journal of the Korean Society of Safety
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    • v.35 no.2
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    • pp.34-46
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    • 2020
  • Unlike research focused on existing technologies and individual errors to analyze the causes of incidents, this study approached them from an organization and culture. And this study is not a one way study but cyclical study what can track cause down using causal loop diagram methodology. Four diagnostic criteria for the negative state of the safety culture : secretive, blame, failure to learning, and incremental learning, combine literature study and expert opinion to derive 41 variables. Connecting these variable make 4 causal loop diagrams and total causal loop diagram. Case accumulation in secretive, accident report in blame, knowledge accumulation in failure to learning, near miss discovery in incremental learning are the main variables. Safety incident is the objective variable by classifying them into 4 stages in total loop, leading track as the most affect is case accumulation, and Step 4 as you can see accident report and near miss discovery are the result of tracking down the cause. This study can be used as a basis for improving the management priority and the system in incident prevention.

New paradigm of common cause human behavior error domain in human-software interation

  • Park, P.;Lee, K.S.
    • Proceedings of the ESK Conference
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    • 1992.10a
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    • pp.84-89
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    • 1992
  • This study is to develop a cognitive paradigm including a new model of common cause human behavior error domain and to analyze their causal factors and their properties of common cause huamn error characteristics in software engineering.l A laboratory study was performed to analyze the common causes of human behavior domain error in software develoment and to indentify software design factors contributing to the common cause effects in common cause failure redundancy. The results and analytical paradigm developed in this resuarch can be applied to reliability improvement and cost reduction in software development for many applications. Results are also expected to provide training guideliness for software engineers and for more effective design of ultra-high reliabile software packages.

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Recent Insights from the International Common-Cause Failure Data Exchange Project

  • Kreuser, Albert;Johanson, Gunnar
    • Nuclear Engineering and Technology
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    • v.49 no.2
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    • pp.327-334
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    • 2017
  • Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE) project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) framework and has successfully been operated over six consecutive terms (the current term being 2015-2017). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers) and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.

Short Bowel Syndrome as the Leading Cause of Intestinal Failure in Early Life: Some Insights into the Management

  • Goulet, Olivier;Nader, Elie Abi;Pigneur, Benedicte;Lambe, Cecile
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.22 no.4
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    • pp.303-329
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    • 2019
  • Intestinal failure (IF) is the critical reduction of the gut mass or its function below the minimum needed to absorb nutrients and fluids required for adequate growth in children. Severe IF requires parenteral nutrition (PN). Pediatric IF is most commonly due to congenital or neonatal intestinal diseases or malformations divided into 3 groups: 1) reduced intestinal length and consequently reduced absorptive surface, such as in short bowel syndrome (SBS) or extensive aganglionosis; 2) abnormal development of the intestinal mucosa such as congenital diseases of enterocyte development; 3) extensive motility dysfunction such as chronic intestinal pseudo-obstruction syndromes. The leading cause of IF in childhood is the SBS. In clinical practice the degree of IF may be indirectly measured by the level of PN required for normal or catch up growth. Other indicators such as serum citrulline have not proven to be highly reliable prognostic factors in children. The last decades have allowed the development of highly sophisticated nutrient solutions consisting of optimal combinations of macronutrients and micronutrients as well as guidelines, promoting PN as a safe and efficient feeding technique. However, IF that requires long-term PN may be associated with various complications including infections, growth failure, metabolic disorders, and bone disease. IF Associated Liver Disease may be a limiting factor. However, changes in the global management of IF pediatric patients, especially since the setup of intestinal rehabilitation centres did change the prognosis thus limiting "nutritional failure" which is considered as a major indication for intestinal transplantation (ITx) or combined liver-ITx.

The Effects of Hyeongbangjihwang-tang and Sibimikwanjung-tang in Glycerol-Induced Renal Failure in Rats (형방지황탕(荊防地黃湯)과 십이미관중탕(十二味寬中湯)이 Glycerol로 유발된 흰쥐의 급성신부전에 미치는 영향)

  • Lee, Hyung-Sun;Kim, Il-Hwan;Kim, Hyo-Soo
    • Journal of Sasang Constitutional Medicine
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    • v.17 no.3
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    • pp.103-112
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    • 2005
  • 1. Objective : The present author have examined the comparative effects of Hyeongbangjihwang-tang and Sibimikwanjung-tang in glycerol-induced acute renal failure, a model for myoglobinuric acute renal failure. 2. Methods : Above two prescriptions were applied to rat ad libitum and serum level of creatinine, glucose and blood urea nitrogen(BUN) were measured. And serum level of $Na^+$, $K^+$ and $Cl^-$, too. 50%(vol/vol) glycerol at a dose of 10 ml/kg of rat body weight intramuscularly and 1% concentration of prescriptions were applied to rats for 7 days ad libitum. 3. Results : Serum level of creatinine and $K^+$ significantly increased by glycerol injection, and these showed pre-renal and renal cause of acute renal failure. Hyeongbangjihwang-tang administered group showed decreasing tendency on serum level of creatinine when compared with control groups, but not significant. Sibimikwanjung-tang administered group showed significant increase of serum level of BUN when compared with control groups. 4. Conclusions : Above two prescriptions showed no significant changes on glycerol induced acute renal failure, but Hyeongbangjihwang-tang and Sibimikwanjung-tang showed a little different manner of response.

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Behavior of Failure for Embankment and Spillway Transitional Zone of Agriculture Reservoirs due to Overtopping (농업용 저수지 월류시 제체와 여수토 접속부의 붕괴거동)

  • Noh, Jae Jin;Lee, Dal Won
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.1
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    • pp.71-79
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    • 2014
  • In this study, an experiment with large-scale model was performed according to raising the embankment in order to investigate the behavior of failure for embankment and spillway transitional zone due to overtopping. The pore water pressure, earth pressure, settlement and failure pattern by a rapid drawdown and overtopping were compared and analyzed. The pore water pressure and earth pressure at spillway transitional zone by overtopping increased a rapidly with the expansion of seepage erosion, but the crest showed a smally change due to effect of the inclined core type. And it is considered an useful data that can accurately estimate the possibility of failure of the reservoirs. A settlement at overtopping decreased a rapidly due to failure of crest. The relative settlement difference due to change of the water level at the upstream and downstream slope cause increase largely crack of crest. The behavior of failure by overtopping was gradually enlarged towards reservoirs crest from the bottom of the spillway transition zone, the inclined core after the raising the embankment was influenced significantly to prevent the seepage erosion.