The steady-state natural convection heat transfer from vertical rectangular fins extending perpendicularly from vertical rectangular base was investigated experimentally. The effects of geometric parameters and base-to-ambient temperature difference on the heat transfer performance of fin arrays were observed and the optimum fin separation values were determined. Two similar experimental set-ups were employed during experiments in order to take measurements from 30 different fin configurations having fin lengths of 250 mm and 340 mm. Fin thickness was maintained fixed at 3 mm. Fin height and fin spacing were varied from 5 mm to 25 mm and 5.75 mm to 85.5 mm, respectively. 5 heat inputs ranging from 25 W to 125 W were supplied for all fin configurations, and hence, the base and the ambient temperatures were measured in order to evaluate the heat transfer rate from fin arrays. The results of experiments have shown that the convection heat transfer rate from fin arrays depends on all geometric parameters and base-to-ambient temperature difference. The effect of these parameters on optimum fin spacing was also examined, and it was realized that for a given base-to-ambient temperature difference, an optimum fin spacing value which maximizes the convective heat transfer rate from the fin array is available for every fin height. The results indicated that the optimum fin spacings are between 8.8 mm and 14.7 mm, for the fin arrays employed in this work. Using the experimental results of present study and experimental results in available literature [2,3,9,10,11,12,14], a correlation for optimum fin spacing at a given fin length and base-to-ambient temperature difference was obtained as a result of scale analysis.

Zugl.: Hamburg, Univ., Diss., 2005

Berlin, Freie Univ., Diss., 2004. / Dateiformat: zip, Dateiein im PDF-Format

This thesis examines the representation of glass in French and Belgian poetry associated with the Symbolist and Decadent movements. It incorporates a number of authors, particularly focussing on Baudelaire, Mallarmé, Laforgue, Rodenbach, and Maeterlinck, but also encompassing more minor writers where appropriate, as well as some writers on the periphery of Symbolism and Decadence. The thesis investigates how the growing use of glass in architecture, technology, and visual art influenced late-nineteenth-century poets, providing these writers with a means by which to understand their social context as well as a multi-faceted metaphor through which to interrogate their own poetic mechanisms. Glass, in its various manifestations - windows, lenses, hothouses, aquariums, Exhibition halls, Art Nouveau glasswork, and stained glass - prompts meditation on such questions as: the interaction between subject and object; the relationship between fiction and reality; the infinite; poetic form; nature and artifice; and aesthetic identity. Ultimately, I combat the traditional understanding of this poetry as being solely concerned with the pure realm of dreams, the soul, and the 'Idée'. Instead, I insist on the material world as a starting point for this poetry, demonstrating that it is not immune to environmental factors, but rather that it uses its environment as a route towards the elusive 'Idée'. Glass is key to this process because its very ambiguity makes it a suitable embodiment of the tension between the material and the unknown, invisible, or ideal.

Ce travail doctoral a pour objectif de mettre en place des méthodes permettant de quantifier les efforts subits par le nageur avec palme, lors de la pratique de 3 activités (Natation, Randonnée Aquatique et Body-Board). Pour ce faire, un modèle utilisant des procédures de dynamique inverse a été mis en place. Dans la première phase de cette étude, la cinématique tridimensionnelle des 3 segments du membre inférieur gauche a été analysée. Il en résulte 3 cinématiques fondamentalement différentes. Avec un modèle type Bottum-Up, la mesure d’efforts distaux est nécessaire. Un robot palmeur a donc été développé, afin de reproduire la cinématique du pied pour chacune des ces pratiques et ainsi permettre une mesure fiable des forces et moments au centre articulaire de la cheville. Ainsi, nous avons quantifié via le modèle, les moments au genou et à la hanche. Ainsi, via le robot nous pouvons quantifier l’effet d’un design de palme sur les efforts subit par l’utilisateur à la cheville, et s’assurer par le modèle que les efforts ne sont pas répercutés sur le genou ou la hanche. En plus de cette étude biomécanique, une analyse de l’activité musculaire a été réalisée sur les principaux muscles moteurs du membre inférieur, pour différentes cinématiques et différents designs de palme. Les résultats nous ont prouvé que le design de la palme a un effet non uniforme sur l’ensemble des muscles, et que pour chacune des pratiques, les demandes musculaires ne sont pas similaires. / The present work had in objective to develop some methods to quantify the joint torque endured by a fin swimmer during is activity for 3 sports (Swimming, Snorkeling, Body-Board). In this way, a model using inverse dynamic methods has been done. During the first step of this study, the 3D kinematic of each activity was mad on the 3 segments of the lower limbs, and this allows defining 3 specifics motions. For a Bottom-Up model, a forces measurement on distal segment is needed to make the calculation. So, a swimming fin robot has been develop to reproduce the foot kinematics for each activity and measure all forces and torques on the ankle joint. By this way, with all this inputs, by the model we can quantify the demands on knee and hip. With this robot, we measure the effect of design modification on muscular request on the joint ankle, and by the model we assure torques are not postpone on knee or hip. In addition to this biomechanical study, a muscular activities study has been realise on the main muscle, and this for different kinematics and different fin blade shapes. The results acknowledge that the fin designs differentiate the effect on specific muscles, and that for each activity the muscular requests are not the same.

La culture de l'honneur, notion primordiale dans la structuration de la société médiévale, fait ici l'objet d'un développement particulier au travers de l'angleterre des xive-xve siècles. cette analyse tente de dresser un tableau global des représentations sociales liées à l'honneur, en particulier dans le contexte de l'affirmation de l'état. sont ainsi explorés les mécanismes d'hybridation ou de rejet entre les diverses appréciations de l'honneur, en analysant notamment l'impact des efforts d'encadrement de l'honneur de la part de l'état ou de l'église dans l'émergence de nouvelles conceptions de l'honneur. dans cette optique, de nombreux développements mettent en lumière la façon dont les individus ou les groupes conçoivent et expriment à leurs niveaux la notion d'honneur, ainsi que les comportements, les attitudes attendues, notamment aux travers des violences d'honneur, qui permettent de s'affirmer dans le regard des autres comme un « homme honorable ». en outre, le cas plus spécifique de la noblesse y est naturellement largement exprimé, en particulier dans la perspective des changements profonds qui affectent ce groupe dans l'Angleterre des XIV-XV siècles, liés à l'affaiblissement des liens de loyauté, à l'émergence des réseaux de clientèle et à l'ouverture de la gentry à de nouveaux membres, dans le cadre du « féodalisme bâtard ». au sein de cette noblesse, une attention spécifique est aussi accordée aux références spécifiques des magnats. / The culture of honor, a vital concept in the structure of medieval society, here is the subject of a particular analysis through england in the late middle age. This analysis attempts to provide a comprehensive overview of social representations of honor, within the main groups in society. In this regard, many developments highlight how individuals and groups perceive and express the concept of honor. This study also aims to show how individuals or groups trying to assert their honorable character, including through violence. In addition, the more specific case of the aristocracy is naturally well treated, in particular in view of the profound changes that have affected this group in england during the fourteenth and fifteenth centuries, related to the phenomenon of "bastard feudalism" and decline in military experience. In addition, this study explains the operating principle of honor, particularly as regards the ties between the honor and social status. This thesis also highlights the impact of state formation on the culture of honor, especially on the honor of the nobles and gentlemen.

Les produits high-tech sont couramment utilisés dans de nombreux secteurs industriels ainsi que dans nos vies de tous les jours. Ils améliorent notre qualité de vie, mais à quel prix ? En effet, la fabrication, l’utilisation et la fin-de-vie de ces produits high-tech génèrent des impacts environnementaux, économiques et sociaux importants. Ces impacts proviennent principalement des matériaux utilisés, de l’énergie consommée pour leur fabrication et pendant leur utilisation et des mauvaises conditions de travail pour l’extraction des matières premières et leur transformation. L’étape de fin-de-vie des produits high-tech contribue également à une grande partie des impacts, car cette phase est souvent négligée lors du processus de conception.Certaines études ont été faites afin de réduire l’impact environnemental des produits, mais ne considèrent qu’une partie des étapes de cycle de vie (par ex. la fabrication) et excluent d’autres étapes comme la fin-de-vie. D’autres études essayent d’intégrer les contraintes de toutes les étapes de cycle de vie mais négligent l’intégration des enjeux environnementaux et ne considèrent que les enjeux classiques de la conception (coûts, qualité, performance, etc.). D’autres études encore visent à intégrer les contraintes de toutes les étapes de cycle de vie et les enjeux environnementaux, mais ne sont pas adaptées à l’évolution rapide des développements dans le cas des produits high-tech (nouvelles technologies, nouveaux matériaux, etc.).Nous proposons donc un outil d’aide à la conception de produits high-tech, qui a pour objectif la prise en compte de toutes les étapes de cycle de vie — et notamment de la fin-de-vie — pour mieux considérer les enjeux environnementaux en plus des enjeux classiques de la conception. Il s’agit d’un modèle-produit agile pour l’écoconception : le MPAE, capable de guider les concepteurs tout au long du processus de conception sur les questions environnementales, malgré les nombreuses alternatives de conception envisagées lors de la conception des produits high-tech.Dans cette thèse, l’outil est appliqué sur un cas théorique de conception avec l’exemple des batteries Li-ion utilisées dans les véhicules électriques. Le modèle développé permet de cibler les paramètres de conception et les acteurs du cycle de vie à l’origine des impacts environnementaux, pour mieux considérer et tenter de les réduire.En résumé, cette thèse réinterroge l’application du concept de modèle produit dans le cas de la prise en compte des impacts environnementaux en conception afin d’aboutir à leur intégration efficace. / High-tech products are widely used in many industrial sectors as well as in our everyday lives. They improve our quality of life, but with a high price to pay? The manufacture, use and end-of-life of these products cause strong environmental, economic and social impacts. These impacts are mainly due to the materials and to the energy used for the manufacturing, to their use, but also to bad working conditions to obtain raw materials. The end-of-life stage for high-tech products is a huge source of impacts because not considered during the design.Some researches have been conducted to reduce the environmental impact of high-tech products, but they only consider partially the life cycle stages (eg. The manufacturing phases) and exclude other stages, such as the end-de- life. Further studies are trying to integrate all the life cycle constraints but neglect the integration of environmental issues and they only consider the classical design constraints (cost, quality, performance, etc.). Other studies aimed at integrating the al the life cycle constraints and the environmental issues, but they are not adapted to quick features evolutions during the design process of high-tech product (new technologies, new materials, etc.We therefore propose a tool to guide the design of high-tech products, which aims to integrate all life-cycle stages including the end-of-life and environmental issues in addition to classic design issues. This is an agile product model for eco-design (APME), which considers the rapid evolution of the solutions during the development of high-tech products.In this thesis, the model is theoretically applied in a case study related to Li-ion batteries for electric automotive applications. The developed model is able to highlight the main design parameters and the main actors of the product life cycle which induce high environmental impacts to try to reduce them.This thesis considers the use of the product model concept when taking into account environmental impacts during the design process, for their efficient integration.

O presente trabalho apresenta um estudo numérico do escoamento laminar em cavidade quadrada aletada sob o efeito de convecção mista. O escoamento proposto é assumido bidimensional, laminar e permanente. Objetiva-se através do “Constructal Design” a obtenção de geometria ótima da aleta de forma a maximizar a transferência de calor entre o fluido que escoa no interior da cavidade e a aleta aquecida cuja base está localizada no centro da base da cavidade. Para isto é fixada a relação das dimensões externas da cavidade (H/L) = 1 e variada a relação entre altura e comprimento da aleta (H1/L1) para otimização da troca térmica. A área da aleta apresenta 5% da área total da cavidade e este valor é mantido fixo. O fluido que escoa no inteiror da cavidade possui as propriedades termofísicas do ar para Pr = 0,7. A variação das forças de empuxo no escoamento é realizada através do uso de diferentes números de Rayleigh no intervalo Ra= 10³ a 106. As diferentes magnitudes das forças inerciais serão aplicadas ao escoamento através da variação do número de Reynolds variando entre ReL = 10 e 1000. Para solução numérica das equações de conservação de massa, quantidade de movimento e energia é utilizado o método de volumes finitos (VFM), programa comercial Fluent®, sendo o acoplamento entre velocidade e pressão realizado através do algoritmo SIMPLEC e a discretização espacial pelo método upwind de primeira ordem. Os resultados apresentam um acréscimo significativo na transferência de calor entre a aleta e o fluido a medida que o número de Rayleigh aumenta. Considerando o caso de maior influência do mecanismo de transferência de calor por convecção mista houve um aumento de 779% em comparação com o mesmo caso considerando apenas convecção forçada, o que comprova a importância da convecção natural na maximização da transferência de calor entre cavidade e fluido para os casos analisados. / The present work shows a numerical study of laminar flow inside C-shaped lid-driven square cavity under mixed convection effect. The flow is assumed to be two-dimensional, laminar and permanent. The main objective of this work is by means of Constructal Design to maximize the heat transfer between the fluid and the heated central fin intruded in the bottom of the cavity. The aspect ratio of the cavity is fixed and the fin aspect ratio (H1/L1) varies from 0.1 to 10 ranges in order to maximize heat transfer. The ratio area between fin and cavity (H/L) = 1 is kept fixed at 5%. The thermophysical properties of fluid the air are set at Pr = 0,71. To vary the magnitude of buoyancy forces the Rayleigh number is ranged between Ra=10³ and 106.The inertial forces of flow are ranged by the use of different Reynolds numbers between ReL=10 and 1000. In order to solve the proposed problem, the commercial software Fluent® based on finite volume method was used to solve mass, momentum and energy equations, making the pressure-velocity couple using SIMPLEC method and the spatial discretization using first order upwind scheme. The results showed a significant increase of heat transfer between fin and fluid as consequence of Rayleigh number increase. Considering the mixed convection most influenced case, an increase of 779% was sense in comparison with the same case with forced convection mechanism only, which makes evident the importance of natural convection in the maximization of heat transfer inside cavity in the analized cases.

Face à un environnement concurrentiel de plus en plus ardu et la montée en force de la réglementation environnementale dans certains secteurs industriels, la supply chain traditionnelle du fabricant d'origine (OEM) devient graduellement insuffisante pour assurer la survie de la firme. En effet, dans certains secteurs industriels, tels que ceux des photocopieurs et des ordinateurs, les firmes ne peuvent plus se contenter d'une unique chaîne de création de valeur. Ces firmes ont mis en place, ou essayent de mettre en place, une seconde chaîne de création de valeur, qui est la reverse supply chain. Cette innovation organisationnelle est fondée principalement sur la création de valeur par le remanufacturing des produits en fin de vie. Bien que les avantages d'une reverse supply chain à des fins de remanufacturing soient démontrés par la recherche académique et des expériences industrielles, le nombre des entreprises, qui sont arrivées à faire émerger une reverse supply chain viable, reste très limité.Cette thèse s'est déroulée dans le cadre d'un projet de recherche multidisciplinaire visant à élaborer une méthodologie d'aide à la conception des systèmes de remanufacturing, à partir d'une recherche intervention chez un industriel intéressé par le remanufacturing de ses produits en fin de vie.Outre notre contribution dans l'élaboration de cette méthodologie, nous avons profité de ce contexte afin d'explorer les facteurs stratégiques qui conditionnent l'émergence d'une reverse supply chain. / As competitiveness increases and environmental legislation toughens, companies can no longer solely rely on traditional supply chain OEM to remain competitive. Indeed for some companies such as copy machine or computer manufacturers, a unique value creation chain is no longer sufficient. These companies have created, or are trying to create, a second valuecreation chain, the reverse supply chain. This organizational innovation is mainly based on creating value through remanufacturing of end of the life products. The benefits of a reverse supply chain clearly emerge in academia and industrial test studies. Yet the number of companies that have been able to create and sustain a viable reverse supply chain is rather limited.This dissertation has been conducted under a multidisciplinary research project. The goal of the project was to create a methodology to facilitate the development of remanufacturing systems based on an intervention research conducted with a company seeking to promote the remanufacturing of its end of life products. This intervention also allowed us, beside to ourcontribution to the development of the remanufacturing methodology, to look into the strategic factors which influence the emergence of a reverse supply chain

Les durcissements réglementaires relatifs à la gestion environnementale et à la responsabilité écologique forcent de plus en plus les industriels à respecter l’environnement dans leur déploiement et développement. A l’heure où on parle de la diminution de la durée de vie des produits de consommation et des biens durables, ces industriels ont désormais la mission de mettre en place des processus de valorisation de leurs produits en fin de vie et des dérivés de leur productions. Cela a été notamment le cas des équipements informatiques et électroniques qui cherchent à concevoir des réseaux logistiques qui répondent aux besoins de gestions des flux de leurs retours comme les DEEE1. En effet, ils sont soumis à des fortes sollicitations (maîtrise des destinations de valorisation de produits en fin de vie, réduction des coûts de traitement, réduction de l’impact des activités logistiques associées sur l’environnement, …). Ce travail s’intéresse à la conception des réseaux logistiques des flux de retours qui sont soumis naturellement aux contraintes économiques mais aussi à celles environnementales. Quelques-uns des facteurs complexifiant du problème comme : l’état de retour, la fluctuation de la demande en produits valorisés, … sont pris en compte dans la recherche de la configuration du réseau logistiques qui répond au mieux aux besoins / Regulatory tightening on environmental management and environmental responsibility increasingly forces industrialists to respect the environment in their deployment and development. At a time when we are talking about the shortening of the life span of consumer products and durable goods, these manufacturers now have the task of putting in place processes for the valorization of their end-of-life products and derivatives of their products productions. This has been the case in particular for computer and electronic equipment which seeks to design logistic networks that meet the management needs of the flows of their returns such as WEEE1. Indeed, they are subject to strong demands (mastery of destinations for valorisation of end-of-life products, reduction of processing costs, reduction of the impact of associated logistical activities on the environment, etc.). This work deals with the design of logistic networks of returns flows which are naturally subject to economic constraints but also to environmental ones. Some of factors of the problem such as: return status, fluctuations in the demand for valued products, etc. are taken into account in the search for the configuration of the logistics network that best meets the needs