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RISS 인기검색어
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- 주제어 : Factors of Performance Degradation (검색결과 6 건)
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김현구(Kim Hyun-Goo) 한국태양에너지학회 2013 한국태양에너지학회 논문집 Vol.33 No.4
This paper investigated wind turbine degradation quantitatively by analyzing the short-term operation records of the Shinan Wind Power Plant. Instead of a capacity factor which is needed to be normalized its variability due to monthly wind speed change, this study suggests an analysis method by taking the difference between the theoretical power output calculated from the nacelle wind speed and actual power output as the quantitative index of performance degradation. For three-year SCADA data analysis of the Shinan Wind Power Plant, it was confirmed that power output degradation rate of 0.54% per year. This value is within the average reduction rate 0.4%/year∼0.9%/year of normalized capacity factor of the onshore wind power plants in U.K. and Denmark; however, lower than the rate 2%/year of Canadian wind power plants.
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농업기반시설물 양ㆍ배수장의 성능저하 요인분석 및 성능평가 모델 개발
이종혁,이상익,정영준,이제명,윤성수,박진선,이병준,이준구,최원 한국농공학회 2019 한국농공학회논문집 Vol.61 No.4
Recently, natural disasters due to abnormal climates are frequently outbreaking, and there is rapid increase of damage to aged agricultural infrastructure. As agricultural infrastructure facilities are in contact with water throughout the year and the number of them is significant, it is important to build amaintenance management system. Especially, the current maintenance management system of pumping and drainage stations among the agriculturalfacilities has the limit of lack of objectivity and management personnel. The purpose of this study is to develop a performance evaluation model usingthe factors related to performance degradation of pumping and drainage facilities and to predict the performance of the facilities in response to climatechange. In this study, we focused on the pumping and drainage stations belonging to each climatic zone separated by the Korea geographical climaticclassification system. The performance evaluation model was developed using three different statistical models of POLS, RE, and LASSO. As the resultof analysis of statistical models, LASSO was selected for the performance evaluation model as it solved the multicollinearity problem between variables,and showed the smallest MSE. To predict the performance degradation due to climate change, the climate change response variables were classifiedinto three categories: climate exposure, sensitivity, and adaptive capacity. The performance degradation prediction was performed at each facility usingthe developed performance evaluation model and the climate change response variables.
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가속열화시험에 의한 부품 · 소재 사용수명 예측에 관한 연구
권영일(Young Il Kwon) 한국신뢰성학회 2017 신뢰성응용연구 Vol.17 No.2
Purpose: Accelerated degradation tests can speed time to market and reduce the test time and costs associated with long term reliability tests to verify the required service life of a product or material. This paper proposes a service life prediction method for components or materials using an accelerated degradation tests based on the relationships between temperature and the rate of failure-causing chemical reaction. Methods: The relationship between performance degradation and the rate of a failure-causing chemical reaction is assumed and least square estimation is used to estimate model parameters from the degradation model. Results: Methods of obtaining acceleration factors and predicting service life using the degradation model are presented and a numerical example is provided. Conclusion: Service life prediction of a component or material is possible at an early stage of the degradation test by using the proposed method.
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Park, H.,Lee, J.S.,Kim, W.,Kim, Y. Applied Science Publishers 2013 APPLIED ENERGY Vol.102 No.-
A hybrid ground-source heat pump (HGSHP) is proposed to overcome the decrease in the performance of a ground-source heat pump (GSHP) at the degraded ground thermal condition. In this study, a performance comparison between the GSHP and the HGSHP with parallel and serial configurations was conducted by varying the leaving fluid temperature (LFT) of the ground heat exchanger (GHEX), the fluid flow rate of the supplemental loop, the mean outdoor bin temperature, and the switching temperature of the hybrid operation. At the LFT of the GHEX of 40<SUP>o</SUP>C, the coefficient of performances (COPs) for the HGSHP with the parallel and serial configurations were 18% and 6% higher than that of the GSHP, respectively. The cooling seasonal performance factors (CSPFs) of the HGSHPs with the parallel and the serial configurations were 6.5% and 2.0% higher, respectively, than that of the GSHP for Daegu city in South Korea.
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Effect of Pitting Corrosion on the Stress Intensity Factor Magnitude and Distribution
Shan-Hua Xu,Haijiang Zhang,Biao Nie,Zhexun Zhang 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4
The fracture and fatigue performance of corroded steel components show signifi cant degradation in both the crack initiation and propagation stage. This study is aimed to research the fracture behavior degradation mechanism of corroded steel members through investigating the eff ects of pits on stress intensity factor magnitude and distribution. The numerical simulation method was adopted, and a series of specimens with diff erent sizes and shapes of corrosion pits were modeled. It was found that the pitting-degradation models would show a more intense displacement and stress fi eld. A greater value of stress intensity factor SIF could be observed in model interior when the specimens were attacked by corrosion pits. The SIF distribution characteristic along thickness direction was aff ected by ratios of pit depth to radius. According to SIF numerical results, the premature fracture and shorter fatigue life induced by corrosion pits could be attributed to the higher SIF value compared with non-corrosion one.
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