Three-Dimensional Aero-Thermal Optimization of Film Cooling in a High Pressure Turbine

Development of effective discrete film cooling is recognized as an essential task in gas turbine design since it has been shown necessary to ensure an acceptable turbine component life-time. Traditional design of film cooling schemes is driven by a single objective, maximizing the cooling performance. The aerodynamic penalty resulting from the coolant injection is generally neglected. Achieving an aero-thermal design of film cooling is a challenging task as it is based on two competing objectives; attaining a high thermal protection of the airfoil from the hot mainstream gas usually results in deteriorating the aerodynamic efficiency. The present research addresses this challenge and investigates the complex flow underlying the aero-thermal interaction on a film cooled airfoil. The simultaneous effects of film coolant flow parameters and film hole geometric variables on the aerodynamic loss and the cooling effectiveness are examined. Trends in design variations to minimize the aerodynamic penalty, while maintaining a high cooling performance are established. The research objective is achieved by implementing an automated optimization procedure that consists of a non-dominated sorting genetic algorithm coupled with an artificial neural network. The latter is used to provide prediction of the objective function at every optimization iteration and reduces computation time. It is constructed based on numerical flow simulations where the three dimensional Reynolds-Averaged Navier-Stokes equations are solved. The optimization methodology is applied on a typical high-pressure turbine with two staggered rows of discrete film cooling on the suction side. The Pareto front of optimal solutions is generated. The thermal, aero-thermal, and aerodynamic optimums are identified and investigated numerically. A subsonic wind-tunnel facility available in Concordia University is used to re-create experimentally the optimum design points. Measured experimental data allowed verification of the CFD model, and substantiated the optimization methodology as a reliable design tool for film cooling in turbomachinery applications

Les récepteurs aux imidazolines dans le coeur : identification, distribution et fonction

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Patrón reproductivo y fecundidad de la merluza (Merluccius merluccius (Linnaeus, 1758)) en el Mediterráneo occidental

12 pages, 12 figures[EN] The spawning cycle of the European hake (Merluccius merluccius, (Linnaeus, 1758)) was studied in two western Mediterranean areas, the Catalan Sea and the northern Tyrrhenian Sea, including observation of the monthly seasonal variation of the gonad maturity and the gonadosomatic index (GSI). The estimation of the maturity stages by GSI gave similar values in the two study areas: the spawning stage (IV) was easily distinguished from the other maturity stages and its range of variation showed a low overlap with stage III and no overlap with other stages. Although in both study areas active females were present during all the sampled months, the peak of reproductive activity was concentrated from February to May in the northern Tyrrhenian Sea but from August to December in the Catalan Sea, which was subjected to winter cascading events. Batch fecundity gave similar values in the Catalan and northern Tyrrhenian Seas: 204 and 202 eggs per gonad-free female gram, respectively. An asynchronous oocyte development is suggested for M. merluccius in the western Mediterranean[ES] Se ha estudiado el ciclo reproductivo de la merluza (Merluccius merluccius, (Linnaeus, 1758)) en dos áreas del Mediterráneo occidental, el Mar Catalán y el norte del Mar Tirreno, analizando la evolución mensual de la madurez en las gónadas y el índice gonadosomático (GSI). La estimación del estadio de madurez mediante el GSI dio resultados parecidos en ambas áreas de estudio: el estadio de puesta (IV) resultó fácil de distinguir de los otros estadios de madurez y su rango de variación mostró poca superposición con el estadio III y ninguna con los otros estadios. Aunque en ambas áreas de estudio se encontraron hembras activas durante todos los meses muestreados, el pico de actividad reproductiva se concentró entre febrero y mayo en el norte del Mar Tirreno, mientras que en el Mar Catalán es entre agosto y diciembre, esta última área sujeta en invierno a fenómenos de cascadas submarinas. La fecundidad relativa presentó valores similares en los mares Catalán y Tirreno norte: 204 huevos por gramo de hembras sin gónada y 202, respectivamente. Se sugiere un desarrollo ovocitario asíncrono para M. merluccius del Mediterráneo occidentalThis work was supported by the EU LLUCET Project (FAIR CT-97-3522)Peer reviewe

Artificial Intelligence in Green Management and the Rise of Digital Lean for Sustainable Efficiency

Artificial intelligence (AI) is a powerful management technology that offers analyzes and insights superior to those made by humans. It cuts costs and saves time by automating repetitive processes, forecasting customer demand and optimizing supply chains while taking into consideration their impact on sustainability and the environment. Organizations become more efficient through the integration of AI, which increases performance and decision-making. This essay examines the use of AI in management and the advent of digital lean, which combines lean manufacturing with technological innovation. The environmental benefits of AI, including energy efficiency and sustainable manufacturing, are also advocated. To realize the environmental sustainability benefits of AI, issues such as data privacy and scalability, as well as the need for responsible AI cooperation and practices, are highlighted

Mechanical effect of friction and stretching on endothelium denudation

Peer reviewed: NoNRC publication: Ye

An unusual giant serpiginous lesion of secondary syphilis.

Syphilis is a worldwide sexually transmitted infection caused by Treponema pallidum subspecies pallidum. Its association with other STIs, including HIV, demands early diagnosis and immediate treatment of patients. We herein report an unusual serpiginous form of secondary syphilis

Acquired pure megakaryocytic aplasia successfully treated with cyclosporine

Acquired pure megakaryocytic aplasia is a rare hematological disorder characterized by thrombocytopenia with absent or markedly reduced megakaryocytes in the bone marrow. We report a case of a 25-year-old male diagnosed as acquired pure megakaryocytic aplasia. Treatment with prednisone and intravenous immunoglobulin failed, but he was successfully treated with cyclosporine, with complete remission after 90 days and normal platelet count maintained thereafter

Contribution à la dépollution des eaux usées de textile par électrocoagulation et par adsorption sur des composés à base de fer et d’aluminium

Les ressources hydriques au monde sont rares et la demande en eau connaît une croissance continue en liaison avec l’évolution démographique et les activités consommatrices en eau, notamment les industries de textiles se voient dans l’obligation de recycler les eaux résiduaires et en particulier celles colorées. Dans ce travail, nous nous sommes intéressés à l’étude de l’élimination des matières organiques et colorantes de deux rejets provenant des industries de textile, un de teinture du tissu de polyester à pH acide et l’autre de teinture du tissu de coton à pH basique. Ces rejets ont été traités de deux manières. La première est par électrocoagulation en utilisant des plaques de fer et/ou d’aluminium. La deuxième est par adsorption sur des composés synthétiques à base de fer et d’aluminium préparés par électrocoagulation. Dans le cas du traitement par le procédé d’électrocoagulation, nous avons constaté que le rendement d’élimination en demande chimique en oxygène (DCO) du rejet de polyester atteint un rendement de DCO de 60% pour un temps de 7 min de réaction. Pour le rejet de coton, le rendement d’élimination, par les plaques de fer/aluminium et l’élimination des matières colorantes, atteint une valeur de 45% en terme de DCO, et ceci en utilisant des plaques d’aluminium seul et de fer/aluminium pour un temps de 12 et 15 min respectivement. Dans le cas du traitement par ajout des coagulants synthétiques préparés au laboratoire, nous pouvons observer que le meilleur rendement d’élimination en DCO du rejet de polyester est obtenu pour une valeur de 48%, pour la faible granulométrie avec une concentration de 5 g/l du composé à base de fer /aluminium. Le rendement d’élimination en DCO du rejet de coton augmente jusqu'à une valeur de 60% avec une concentration de 5 g/l de coagulants appliqués à base d’aluminium seul. Les résultats de la dépollution de ces rejets, ont montré que le rendement d'élimination des matières organiques et colorantes par le procédé d'électrocoagulation est important, et la durée de traitement est courte, mais l'inconvénient de ce procédé c'est la saleté des plaques après chaque utilisation et la fabrication d'une grande quantité des boues par rapport à l’adsorption sur des composés à base de fer /aluminium où on utilise des poudres peu solubles et stables avec un bon rendement d’élimination et faibles quantités de fer et d'aluminium dans le surnageant traité.Keywords: Colorant textile, électrocoagulation, adsorption, dépollution, fer, aluminiu