Uncertainty in Operational Modal Analysis of Hydraulic Turbine Components

Gagnon, Martin,Tahan, S.-Antoine,Coutu, Andre Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.4

Operational modal analysis (OMA) allows modal parameters, such as natural frequencies and damping, to be estimated solely from data collected during operation. However, a main shortcoming of these methods resides in the evaluation of the accuracy of the results. This paper will explore the uncertainty and possible variations in the estimates of modal parameters for different operating conditions. Two algorithms based on the Least Square Complex Exponential (LSCE) method will be used to estimate the modal parameters. The uncertainties will be calculated using a Monte-Carlo approach with the hypothesis of constant modal parameters at a given operating condition. In collaboration with Andritz-Hydro Ltd, data collected on two different stay vanes from an Andritz-Hydro Ltd Francis turbine will be used. This paper will present an overview of the procedure and the results obtained.

The Effect of Exchange Rates on Prices, Wages, and Profits: A Case Study of the United Kingdom in the 1990's.

Gagnon, Joseph E.,Costas Karfakis,Zhang, Shuo 한국국제경제학회 2006 International Economic Journal Vol.20 No.2

New insights about ice friction obtained from crushing-friction tests on smooth and high-roughness surfaces

Gagnon, Robert E. The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.3

Ice crushing occurs in many situations that involve a sliding frictional component such as sports involving ice-contact, ice interaction with ship hulls, and ice-on-ice sliding/crushing within glaciers and between interacting sea ice floes. Ice crushing-friction tests were conducted in the lab at $-10^{\circ}C$ using a set of acrylic ice-crushing platens that included a flat smooth surface and a variety of high-roughness surfaces with regular arrays of small prominences. The experiments were part of Phase II tests of the Blade Runners technology for reducing ice-induced vibration. Ice was crushed against the platens where the ice movement had both a vertical and a horizontal component. High-speed imaging through the platens was used to observe the ice contact zone as it evolved during the tests. Vertical crushing rates were in the range 10-30 mm/s and the horizontal sliding rates were in the range 4.14-30 mm/s. Three types of freshwater ice were used. Friction coefficients were extraordinarily low and were proportional to the ratio of the tangential sliding rate and the normal crushing rate. For the rough surfaces all of the friction coefficient variation was determined by the fluid dynamics of a slurry that flowed through channels that developed between leeward-facing facets of the prominences and the moving ice. The slurry originated from a highly-lubricating self-generating squeeze film of ice particles and melt located between the encroaching intact ice and the surfaces.

신라 금관의 조형성을 응용한 에스닉 주얼리 형태의 디자인 개발 연구

게그논옥숙 ( Gagnon Ok-suk ),안일훈 ( Ahn Il-hoon ) 한국디자인트렌드학회 2016 한국디자인포럼 Vol.52 No.-

연구배경 신라 금관의 양적 풍부선과 분포의 집중선, 질적 독창성, 그리고 형상의 상징성을 고려하면 우리나라를 대표할 수 있는 조형물로 인식 할 수 있다. 또한 금관의 역사적 배경은 궁극적으로는 민족성의 반영과 그 특색 및 형성은 또한 그 시대를 대변한다. 전통적인 요소의 현대적 활용 방안에 관한 논의는 이전에도 이루어져 왔지만 포스트모더니즘의 영향과 에스닉 스타일의 유행을 배경으로 더욱 확대되어 다양한 디자인 분야에서 전통 문화의 활용 방안이 모색되어지고 있다. 연구방법 신라 금관의 조형적 특징과 가치를 분석 후, 신라 금관을 형태적 재해석을 통해 에스닉 디자인적 요소들의 특성을 알아보고자 하며, 이를 바탕으로 분석된 표현들을 통해 신라 금관의 현대적 디자인에 초점을 맞추고자 하였다. 디자인적인 시각적 즐거움과 장신구의 원상의 복제, 동일개체의 조합, 반복에 의한 프랙탈 이미지 작업을 통해 기존의 신라 금관의 조형 형태에 중점을 둔 디자인 전개로 기존 신라 금관의 조형 형태를 변형한 작품을 제작하였고, 고정된 정형적인 모습에서 벗어나 신라 금관의 조형에 대한 새로운 착용방법과 조형성을 디자인 하였다. 연구결과 다양화되고 차별화된 취향과 감각을 가지고 있는 주얼리 소비자들을 위해 보다 차별화된 컨셉으로 신라 금관의 주얼리 디자인 주제로 충분히 활용가능 하였다. 결론 우리 고유의 전통문화를 응용한 창조적 발전·활용 가능성 제시할 수 있어 주얼리 디자인 분야의 새로운 디자인 소재로도 충분히 활용 가능 하다는 것을 도출할 수 있었다. Background The use of traditional elements in contemporary jewelry design has been widely discussed previously but the attention to the postmodernism`s effects have increased just recently. Ethnic style jewelry brings diversity to a world of design, tolerance of ambiguity, mixing of styles, and acceptance of innovation and change which are distinct to modernism forms. Such effects are thought to be a result of changes in the consumers` values for their own lifestyles. Methods In the world of design, consumer preferences and ideas on creative design should be reflected. Design is about putting aesthetics in a particular item and by aesthetics it signifies the cultural artistic element. In the modern world, it is not sufficient to compete only with cost benefits or functional elements. Both economical and esthetical aspects should be considered in order to satisfy a wide range of consumers` needs. The selection of traditional elements with new approach to jewelry design and the utilization capacity is necessary to become a world famous design. Result This study was able to draw on the fact that it is possible for the Shilla Dynasty Gold Crown to be a design subject which would satisfy consumers in the modern generation with a large variety of tastes. Furthermore, ethnic jewelry can be used for new jewelry design in the future. A framework in bringing the new spotlight to Shilla Dynasty Gold Crown was established through redesigning jewelry to fit modern preferences. Conclusion In the future, the jewelry design should not only emphasize its formative characteristics, but also allow spiritual consensus.

New insights about ice friction obtained from crushing-friction tests on smooth and high-roughness surfaces

Robert E. Gagnon 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.3

Ice crushing occurs in many situations that involve a sliding frictional component such as sports involving ice-contact, ice interaction with ship hulls, and ice-on-ice sliding/crushing within glaciers and between interacting sea ice floes. Ice crushing-friction tests were conducted in the lab at 10 C using a set of acrylic ice-crushing platens that included a flat smooth surface and a variety of high-roughness surfaces with regular arrays of small prominences. The experiments were part of Phase II tests of the Blade Runners technology for reducing ice-induced vibration. Ice was crushed against the platens where the ice movement had both a vertical and a horizontal component. High-speed imaging through the platens was used to observe the ice contact zone as it evolved during the tests. Vertical crushing rates were in the range 10e30 mm/s and the horizontal sliding rates were in the range 4.14e30 mm/s. Three types of freshwater ice were used. Friction coefficients were extraordinarily low and were proportional to the ratio of the tangential sliding rate and the normal crushing rate. For the rough surfaces all of the friction coefficient variation was determined by the fluid dynamics of a slurry that flowed through channels that developed between leeward-facing facets of the prominences and the moving ice. The slurry originated from a highly-lubricating self-generating squeeze film of ice particles and melt located between the encroaching intact ice and the surfaces.

제주도 해군 기지 반대 투쟁의 현황

브루스 개그넌(Bruce Gagnon),최성희(번역자) 노동사회과학연구소 2010 정세와노동 Vol.- No.55

진퇴양난에 빠진 카나다와 퀘벡

알렝가뇽,정지용 서울대학교 불어문화권연구소 1992 불어문화권연구 Vol.2 No.-

Schooling for a Stateless Nation: The Predicament of Education without Consensus for Karen Refugees on the Thailand-Myanmar Border

여수빈,Terese Gagnon,Hayso Thako 서울대학교 통일평화연구원 2020 Asian Journal of Peacebuilding Vol.8 No.1

This article addresses the issue of schooling for refugees, as members of a stateless nation, in the context of Karen refugees in Thailand. The authors used ethnographic methods of in-depth, semi-structured interviews and participant observation with over 250 residents of Mae La refugee camp. Our conceptual framework draws on theories of pedagogy for liberation and grassroots development. We found that, due to overlapping sources of authority with divergent visions of the future for refugee learners, the existential crisis of being members of a stateless nation is the most pressing issue for education to address. We suggest that a top-down approach to refugee education relying on technical solutions, while ignoring issues of history, power, and meaning-making, will ultimately fall short of being fundamentally transformative.

The effect of materials properties on the reliability of hydraulic turbine runners

Thibault, Denis,Gagnon, Martin,Godin, Stephane Korean Society for Fluid machinery 2015 International journal of fluid machinery and syste Vol.8 No.4

The failure of hydraulic turbine runners is a rare event. So in order to assess the reliability of these components one cannot rely solely on the number of observed failures in a given population. However, as there is a limited number of degradation mechanisms involved, it is possible to use physically-based reliability models. Such models are often more complicated but are able to account for physical parameters in the degradation process. They can therefore help provide solutions to improve reliability. With such models, the effect of materials properties on runner reliability can be highlighted. This paper presents a brief review of the Kitagawa-Takahashi diagram which links the damage tolerance approach, based on fracture mechanics, to the stress or strain-life approaches. Using simplified response spectra based on runner stress measurements, we will show how fatigue reliability is sensitive to materials fatigue properties, namely fatigue crack propagation behaviour and fatigue limit obtained on S-N curves. Furthermore, we will review the influence of the main microstructural features observed in 13%Cr-4%Ni stainless steels commonly used for runner manufacturing. The goal is ultimately to identify the most influential microstructural features and to quantify their effect on fatigue reliability of runners.

Fostering life skills development in studentathletes: The experiences of high school sport psychology consultants

Christiane Trottier,Stephanie Gagnon,Penelope Duval-Brassard,Roxane Carriere 한국코칭능력개발원 2023 International Journal of Coaching Science Vol.17 No.2

School sport provides a structured setting for teaching life skills. Although the research has focused mainly on coaches, sport psychology consultants (SPCs) can also foster positive development in student-athletes. The objective of this study was to examine the experiences of SPCs in teaching life skills development and transfer to student-athletes in sport-study programs specific to high school settings. A basic qualitative study consistent with a constructivist paradigm was used. Semi-structured interviews were held with seven SPCs employed in a sport-study program. First, results revealed that all SPCs held a holistic philosophy and aimed for student-athletes’ positive development. Second, SPCs incorporated some life skills development and transfer strategies into their interventions (e.g., workshops, group discussions). Third, SPCs encountered certain challenges in teaching life skills development and transfer, and particularly in following up on life skills transfer and working with other stakeholders (e.g., psychoeducators, social workers). Despite the SPCs’ efforts to teach life skills development and transfer, the results highlight the need for better training in effective interventions.