Dans le domaine des transports maritimes de Gaz Naturel Liquide (GNL), une problématique majeure est le risque de rupture mécanique liée à une température trop froide des parois du méthanier. Ainsi le dimensionnement des navires nécessite la connaissance précise des champs de températures. L’obtention de ces champs de température peut nécessiter de nombreuses heures de calculs et encore plus en prenant en compte les phénomènes radiatifs. L’objectif de cette thèse est de présenter une méthode permettant la résolution de ce problème en quelques minutes en tenant compte des phénomènes de thermiques (conduction, convection et radiation). La méthode de réduction modale utilisée ici consiste à créer un modèle réduit composé de champs de température particuliers appelés modes. On a pu démontrer que la résolution est quasi instantanée pour une erreur minime sur une portion de navire et il est envisagé de développer la méthode à l’ensemble d’un navire. / In the sector of maritime transport of Liquid Natural Gas (LNG), a major issue is the risk of mechanical failure linked to too cold vessel walls. Thus, the design of LNG carrier requires precise expertise of temperatures fields. These are complex structures made up of a large number of enclosures. To obtain these fields it may require many hours of calculations,particularly if we take in account the radiations. The aim of this thesis is to present a method to solve in a few minutes all of thermal phenomena (conduction, convection and radiation) on a big structure and obtain transient temperature’s fields.The method of modal reduction used here consist to create a reduced model composed of individual temperature fields called modes allowing a very quick resolution with minor error. It has been shown the truth of the method on a vessel portion and there are plans to develop the method to the entire ship.

No description available.

In this thesis, Giddens' theory of structuration is employed in an analysis of the ghetto of ex-psychiatric patients in Hamilton, Ontario. A review of the main concepts of of structuration theory forms the basis for a theoretical model of the structuration of urban space that considers both the individual agent and the social system as equal partners in the production and reproduction of the urban built environment. From this general model, methodologies are developed for institutional analysis and an analysis of strategic conduct. The institutional analysis enables an understanding of the ghetto as the unintended outcome of deinstitutionalization policy. An examination of the city of Hamilton's attempt to dismantle the ghetto focuses on the strategic conduct of the actors in the policy-making process, and provides insight as to why the city's attempt has thus far proved unsuccessful in halting the ghettoization of ex-patients. The study demonstrates the theoretical and empirical utility of structuration theory in providing an analysis that considers the complex interrelationships of system, structure, agency, time and space. / Thesis / Master of Arts (MA)

Dans cette thèse nous présentons différents motifs formés par auto-organisation de matériaux azopolymères soumis à un rayonnement lumineux. Nous avons montré que de nombreux réseaux de surface photoinduits, jusqu'à 10, peuvent êtreenregistrés sur la même zone d’un film azopolymère pourvu que la polarisation du faisceau d'écriture soit bien choisie. Cet effet a permis la création d'une grande variété de motifs complexes. Dans cette thèse, nous montrons de telles structures complexes formées à la surface de couches minces d'azopolymère via un ensemble de réseaux superposés (jusqu'à 16 sur la même zone). Nous créons ainsi des structures dites quasi-cristal à 2 dimensions. La surface d'azopolymère est alors utilisée comme un moule afin d'être répliquée avec un élastomère. La couche d’élastomère ainsi produite possède la même structure que le moule enazopolymère. Cette couche est flexible, transparente et étirable et nous l'avons utilisé pour le dépôt de nano-objets uniques. Les caractéristiques de deux surfaces photoinduites de deux azopolymères chiraux ont été comparées: une surface aléatoire de type gaussien et une surface avec des réseaux quasi-aléatoires. Ces motifs ont été obtenus avec une technique simple de type ‘bottom-up’ en éclairant la couche mince d'azopolymère avec un seul faisceau laser. La surface avec des réseaux quasi-aléatoires peut être utilisée pour le couplage de la lumière dans plusieurs directions dans un film ultra-mince. Ces deux surfaces ont été utilisées comme moule et répliquées sur un élastomère transparent. Elles montrent un très bon piégeage de la lumière. Plus précisément, le piégeage de la lumière est 20% meilleur avec les réseaux quasialéatoires qu'avec la surface aléatoire de type gaussien et il est de l'ordre de 40%. / In this thesis we present various patterns formed by self-organization of azopolymer materials subjected to light radiation. We have shown that many photoinduced surface gratings, up to 10, can be recorded on the same area of an azopolymer film, provided that the polarization of the writing beam is well chosen. This effect allowed the creation of a wide variety of complex patterns. In this thesis, we show such complexstructures formed on the surface of thin layers of azopolymer, via a set of superimposed networks (up to 16 on the same zone). We thus create so-called quasicrystal structures with 2 dimensions. The azopolymer surface is then used as a mold to be replicated with an elastomer. The elastomer layer produced has the same structure as the azopolymer mold. This layer is flexible, transparent and stretchable and we used it for the deposition of unique nano-objects. The characteristics of two photoinduced surfaces of two chiral azopolymers were compared: a Gaussian type random surface and a surface with quasi-random lattices. These patterns were obtained with a simple bottom-up technique, by illuminating the thin layer of azopolymer with a single laser beam. The surface with quasi-random lattices can be used for the coupling of light in several directions in an ultra-thin film. These two surfaces were used as molds and replicated on a transparent elastomer. They show a very good trapping of light. More precisely, the trapping of the light is 20% better with the quasi-random gratings than with the random surface of the Gaussian type and it is of the order of 40%.

Esta pesquisa objetiva compreender o processo de estruturação das redes sociais virtuais organizacionais, as quais são espaços de colaboração, interação e compartilhamento de conhecimentos, ideias e projetos. As redes foram estudadas a partir da Teoria da Estruturação, de Giddens (2009), destacando-se a dualidade da estrutura e as reflexões quanto ao contexto de ação (dimensões tempo e espaço). A pesquisa compreendeu um estudo de caso em uma Instituição de Ensino Superior, tendo três redes sociais virtuais organizacionais, denominados “Fóruns”, como unidades de análise. A organização está distribuída geograficamente em 10 Campi localizados em diferentes cidades, de modo que essas redes têm o papel de integrar os atores e possibilitar as trocas de experiências, auxiliando no processo de construção da identidade das áreas e da Universidade. Os Fóruns têm como propósito discutir e deliberar sobre assuntos relacionados aos cursos de graduação em diferentes níveis de conhecimento, sendo caracterizados pelas diversas áreas do conhecimento e possibilitando a participação espontânea dos atores em qualquer tempo. A investigação deu-se através de observação participante, entrevistas e análise de documentos. Os resultados apontam que as redes constituem-se à medida que os grupos determinam os seus objetivos de trabalho, o que remete à definição de uma agenda de trabalho, de recursos, papéis e estruturas. Cada rede possui um coordenador responsável, que se configura como o mediador e o incentivador das interações que ocorrem presencial e virtualmente. As ferramentas virtuais, também, são determinadas pelos atores com base nas atividades a serem desenvolvidas, podendo abranger tecnologias de comunicação ou instrumentais como editores de texto colaborativos. Foram elencados os elementos constituintes das redes sociais virtuais organizacionais, os quais não são estanques e podem alterar-se conforme os Fóruns mudam os seus propósitos de ação. Percebe-se que, a cada encontro, ou quando determinados novos objetivos e tarefas, ou nas inserções de novos membros, a rede reconfigura-se, reproduzindo outras características, alterando a sua composição, emergindo novas estruturas, novos papéis e novas regras, os quais são definidos pela coletividade. Os resultados apontam que a rede é um espaço participativo de integração e de construção da identidade dos cursos, das áreas de conhecimento e da Universidade. Para que a rede tenha significado para os atores é necessária à existência de elementos que sirvam como elo entre os atores e que justifiquem o trabalho coletivo. A rede torna os atores mais reflexivos e é um espaço de reflexão sobre a Universidade e a atuação docente, desenvolvendo as interações pela lógica do debate. Os participantes utilizam os seus conhecimentos e as experiências para reforçar os discursos, assim como as normas norteiam e justificam as ações dos atores. A rede dá acesso a todos os níveis hierárquicos da organização e a recursos materiais, financeiros, informacionais e de conhecimentos. Portanto, a rede é um ambiente de articulação e legitimação das decisões e das normas organizacionais, dando substancialidade para a organização. Dessa forma, as redes consolidam-se a partir da rotinização das práticas, formando estruturas, construindo uma identidade compartilhada que serve de elemento agregador para o grupo. / This research aims to understand the structuration process of organizational virtual social networks, which are opportunities for collaboration, interaction and sharing of knowledge, ideas and projects. The networks were studied based on the Theory of Structuration, Giddens (2009), highlighting the duality of structure and reflections on the action context (time and space dimensions). This research is a case study performed in a Higher Education Institution, and the analysis units were three organizational virtual social networks, called ‘Forums’. The organization is geographically distributed in 10 campi located in different cities, and the networks have the role to integrate the actors and enable the sharing of experience, assisting in the process of the identity construction of the areas and the University. The Forums aimed to discuss and deliberate on issues related to undergraduate courses at different levels of knowledge. They were characterized by different areas of knowledge and allowed the spontaneous participation of the actors at any time. The investigation was carried out through participant observation, interviews and document analysis. The results show that networks are formed as the groups determine their work objectives, which lead to the definition of a work schedule, resources, roles and structures. Each network has a coordinator responsible for being the mediator and the instigator of the interactions that occur in person and virtually. The virtual tools are determined by the actors based on the activities to be developed, and they may include communication or instrumental technologies such as collaborative text editors. We listed the elements constituent of organizational virtual social network, which are not steady and may change as they change their Forum purposes of action. Therefore, it is clear that at each meeting, when some new goals and tasks are determined, or in the insertion of new members, the network reconfigures itself, reproducing other features, changing its composition, and bringing out new structures, roles and rules, which are defined by the community. The results show that the network is a participative space of integration and identity construction of courses, areas of knowledge and the University. The network is meaningful if the actors identify elements that serve as a link between them and justify the collective work. The network makes the actors more reflective and is a reflection about the University and the teaching practice, developing the interactions by the logic of the debate. Participants use their knowledge and experiences to strengthen the speeches. The norms guide and justify the actions of actors. The network gives access to higher levels of the organization as well as to material, financial, informational, and knowledge resources. Therefore, the network is an environment of articulation and legitimation of decisions and organizational norms, giving substantiality to the organization. Networks are consolidated from the routinization of practices, forming structures and the establishment of a shared identity that serves as an aggregating element to the group.

Le sujet de thèse concerne la maîtrise de la texturation de milieux granulaires par l'étude des dynamiques de structuration et de consolidation et l'application aux poudres céréalières réactives. La démarche s'appuie sur la confrontation d'approches scientifiques complémentaires (physique, physico-chimiques, génie des procédés et technologiques) pour étudier les dynamiques (i.e. évolutions cinétiques sous contraintes mécaniques) de structuration, de croissance, de rétraction et de consolidation. La méthodologie s'appuie sur la mise en œuvre d'une approche multi échelles. (i) À l'échelle des procédés, avec une approche technologique (basée sur une étude paramétrique avec des expérimentations à l'échelle pilote) et avec la construction d'un modèle de description des processus. (ii) À l'échelle des mécanismes pour étudier la génération de contacts (i.e. mécanismes de croissance) et la consolidation des interfaces (i.e. mécanismes de solubilisation & de séchage), avec des approches physico-chimiques expérimentales et le développement de modèles mécanistiques. (iii) À l'échelle de la structure : description de la microstructure interne (distribution de la compacité) et des caractéristiques texturales locales des structures formées. La thèse de doctorat prend en compte la réactivité des poudres pour la construction de modèles mécanistiques de croissance et de consolidation des milieux granulaires. Ces travaux trouvent des applications évidentes pour la filière céréales. / The PhD thesis subject concerns the control of the structures of granular matters, by the study of the dynamics of structuring and consolidation, and the application in reactive cereal powders. The approach leans on the confrontation of complementary scientific approaches (physical, physico-chemical, process engineering and technological) to study the dynamics (i.e. kinetic evolutions under mechanical stresses) of structuring, growth, shrinkage and consolidation. The experimental methodology is based on a multi-scales approach. (i) On the scale of the processes, with a technological approach (based on a parametric study with experiments using pilot scales equipments) and with the construction of a descriptive model of the reactions. (ii) On the scale of mechanisms, to study the generation of contacts (i.e. mechanisms of growth) and the consolidation of the interfaces (i.e. mechanisms of solubilization and drying), with experimental physico-chemical approaches and development of mechanistic models. (iii) On the scale of the structure, with the description of the intern microstructure (distribution of the compactness) and the measurement of local characteristics of the structures. The PhD thesis takes into account the reactivity of powders for the construction of mechanistic models to describe the growth and the consolidation mechanisms of the granular matter. These works find obvious applications for the cereal sector.

Esta pesquisa objetiva compreender o processo de estruturação das redes sociais virtuais organizacionais, as quais são espaços de colaboração, interação e compartilhamento de conhecimentos, ideias e projetos. As redes foram estudadas a partir da Teoria da Estruturação, de Giddens (2009), destacando-se a dualidade da estrutura e as reflexões quanto ao contexto de ação (dimensões tempo e espaço). A pesquisa compreendeu um estudo de caso em uma Instituição de Ensino Superior, tendo três redes sociais virtuais organizacionais, denominados “Fóruns”, como unidades de análise. A organização está distribuída geograficamente em 10 Campi localizados em diferentes cidades, de modo que essas redes têm o papel de integrar os atores e possibilitar as trocas de experiências, auxiliando no processo de construção da identidade das áreas e da Universidade. Os Fóruns têm como propósito discutir e deliberar sobre assuntos relacionados aos cursos de graduação em diferentes níveis de conhecimento, sendo caracterizados pelas diversas áreas do conhecimento e possibilitando a participação espontânea dos atores em qualquer tempo. A investigação deu-se através de observação participante, entrevistas e análise de documentos. Os resultados apontam que as redes constituem-se à medida que os grupos determinam os seus objetivos de trabalho, o que remete à definição de uma agenda de trabalho, de recursos, papéis e estruturas. Cada rede possui um coordenador responsável, que se configura como o mediador e o incentivador das interações que ocorrem presencial e virtualmente. As ferramentas virtuais, também, são determinadas pelos atores com base nas atividades a serem desenvolvidas, podendo abranger tecnologias de comunicação ou instrumentais como editores de texto colaborativos. Foram elencados os elementos constituintes das redes sociais virtuais organizacionais, os quais não são estanques e podem alterar-se conforme os Fóruns mudam os seus propósitos de ação. Percebe-se que, a cada encontro, ou quando determinados novos objetivos e tarefas, ou nas inserções de novos membros, a rede reconfigura-se, reproduzindo outras características, alterando a sua composição, emergindo novas estruturas, novos papéis e novas regras, os quais são definidos pela coletividade. Os resultados apontam que a rede é um espaço participativo de integração e de construção da identidade dos cursos, das áreas de conhecimento e da Universidade. Para que a rede tenha significado para os atores é necessária à existência de elementos que sirvam como elo entre os atores e que justifiquem o trabalho coletivo. A rede torna os atores mais reflexivos e é um espaço de reflexão sobre a Universidade e a atuação docente, desenvolvendo as interações pela lógica do debate. Os participantes utilizam os seus conhecimentos e as experiências para reforçar os discursos, assim como as normas norteiam e justificam as ações dos atores. A rede dá acesso a todos os níveis hierárquicos da organização e a recursos materiais, financeiros, informacionais e de conhecimentos. Portanto, a rede é um ambiente de articulação e legitimação das decisões e das normas organizacionais, dando substancialidade para a organização. Dessa forma, as redes consolidam-se a partir da rotinização das práticas, formando estruturas, construindo uma identidade compartilhada que serve de elemento agregador para o grupo. / This research aims to understand the structuration process of organizational virtual social networks, which are opportunities for collaboration, interaction and sharing of knowledge, ideas and projects. The networks were studied based on the Theory of Structuration, Giddens (2009), highlighting the duality of structure and reflections on the action context (time and space dimensions). This research is a case study performed in a Higher Education Institution, and the analysis units were three organizational virtual social networks, called ‘Forums’. The organization is geographically distributed in 10 campi located in different cities, and the networks have the role to integrate the actors and enable the sharing of experience, assisting in the process of the identity construction of the areas and the University. The Forums aimed to discuss and deliberate on issues related to undergraduate courses at different levels of knowledge. They were characterized by different areas of knowledge and allowed the spontaneous participation of the actors at any time. The investigation was carried out through participant observation, interviews and document analysis. The results show that networks are formed as the groups determine their work objectives, which lead to the definition of a work schedule, resources, roles and structures. Each network has a coordinator responsible for being the mediator and the instigator of the interactions that occur in person and virtually. The virtual tools are determined by the actors based on the activities to be developed, and they may include communication or instrumental technologies such as collaborative text editors. We listed the elements constituent of organizational virtual social network, which are not steady and may change as they change their Forum purposes of action. Therefore, it is clear that at each meeting, when some new goals and tasks are determined, or in the insertion of new members, the network reconfigures itself, reproducing other features, changing its composition, and bringing out new structures, roles and rules, which are defined by the community. The results show that the network is a participative space of integration and identity construction of courses, areas of knowledge and the University. The network is meaningful if the actors identify elements that serve as a link between them and justify the collective work. The network makes the actors more reflective and is a reflection about the University and the teaching practice, developing the interactions by the logic of the debate. Participants use their knowledge and experiences to strengthen the speeches. The norms guide and justify the actions of actors. The network gives access to higher levels of the organization as well as to material, financial, informational, and knowledge resources. Therefore, the network is an environment of articulation and legitimation of decisions and organizational norms, giving substantiality to the organization. Networks are consolidated from the routinization of practices, forming structures and the establishment of a shared identity that serves as an aggregating element to the group.

Les vidéos sont de plus en plus utilisées dans un contexte pédagogique, mais les formats de présentation sur les plateformes spécialisées (e.g., MOOC) sont variés et peu analysés. Il paraît cependant nécessaire de s’intéresser aux processus à l’oeuvre lors des tâches d’apprentissage et de recherche d’information (RI) pour adapter au mieux les environnements vidéo aux besoins et ressources cognitifs des individus. Au cours de ces deux tâches (RI et apprentissage), la littérature scientifique fait apparaître l’importance de la qualité du modèle mental de l’individu. Pour favoriser la construction d’un modèle mental pertinent par l’individu, deux types d’étayage sont envisagés au cours de cette thèse : la segmentation de la barre de navigation et la structuration du contenu de la vidéo par une table des matières. Les trois premières études ont permis de montrer que la présence conjointe des deux niveaux d’étayage a favorisé la performance en RI (étude 1), mais qu’elle n’a pas permis la construction d’un modèle mental efficace du contenu de la vidéo (étude 2). Au cours de l’étude 3, différents formats de présentation ont été comparés : le format pop-up a permis de diminuer la difficulté perçue de la tâche de RI. Les deux dernières études se sont centrées sur les effets de l’étayage lors d’une tâche d’apprentissage. La présence d’étayage n’a pas amélioré la qualité de l’apprentissage (étude 4). Néanmoins, lorsque l’apprenant est rendu actif, grâce à une tâche de RI par exemple, la mémorisation du contenu de la vidéo a été améliorée (étude 5). Les résultats sont discutés en termes de rôle organisateur de l’étayage permettant une récupération efficace de l’information. L’étayage organiserait l’information entrante dans l’environnement vidéo ou la mémoire de l’individu selon la tâche. / Videos are more and more used in pedagogical contexts, but presentation formats on specific platforms (e.g., MOOC) are varied and not so much analyzed. However, it seems necessary to focus on processes involved during learning and information seeking (IS) tasks to adapt video-based environments to individuals’ needs and cognitive resources. During learning and IS, scientific literature highlights the importance of individuals’ mental models. To encourage the construction of a relevant mental model, two types of scaffolding are considered in this thesis: the segmentation of the timeline and the structuration of the video content using a table of contents. The first three studies showed that the conjoint use of the two levels of scaffolding enhanced IS performance (study 1), but it did not promote the construction of a relevant mental model of the video content (study 2). During study 3, several presentation format were compared: the pop-up format reduced perceived difficulty of the IS task. The last two studies focused on the effects of scaffolding during a learning task. The presence of scaffolding did not enhanced learning performance (study 4). Nevertheless, when the learner was made active, thanks to an IS task for example, memorization of the video content was improved (study 5). Results are discussed in terms of organizing role of scaffolding enabling effective recovery of information. Scaffolding is here thought to organize incoming information in the video-based environment or in individual’s memory according to the task.

Esta pesquisa objetiva compreender o processo de estruturação das redes sociais virtuais organizacionais, as quais são espaços de colaboração, interação e compartilhamento de conhecimentos, ideias e projetos. As redes foram estudadas a partir da Teoria da Estruturação, de Giddens (2009), destacando-se a dualidade da estrutura e as reflexões quanto ao contexto de ação (dimensões tempo e espaço). A pesquisa compreendeu um estudo de caso em uma Instituição de Ensino Superior, tendo três redes sociais virtuais organizacionais, denominados “Fóruns”, como unidades de análise. A organização está distribuída geograficamente em 10 Campi localizados em diferentes cidades, de modo que essas redes têm o papel de integrar os atores e possibilitar as trocas de experiências, auxiliando no processo de construção da identidade das áreas e da Universidade. Os Fóruns têm como propósito discutir e deliberar sobre assuntos relacionados aos cursos de graduação em diferentes níveis de conhecimento, sendo caracterizados pelas diversas áreas do conhecimento e possibilitando a participação espontânea dos atores em qualquer tempo. A investigação deu-se através de observação participante, entrevistas e análise de documentos. Os resultados apontam que as redes constituem-se à medida que os grupos determinam os seus objetivos de trabalho, o que remete à definição de uma agenda de trabalho, de recursos, papéis e estruturas. Cada rede possui um coordenador responsável, que se configura como o mediador e o incentivador das interações que ocorrem presencial e virtualmente. As ferramentas virtuais, também, são determinadas pelos atores com base nas atividades a serem desenvolvidas, podendo abranger tecnologias de comunicação ou instrumentais como editores de texto colaborativos. Foram elencados os elementos constituintes das redes sociais virtuais organizacionais, os quais não são estanques e podem alterar-se conforme os Fóruns mudam os seus propósitos de ação. Percebe-se que, a cada encontro, ou quando determinados novos objetivos e tarefas, ou nas inserções de novos membros, a rede reconfigura-se, reproduzindo outras características, alterando a sua composição, emergindo novas estruturas, novos papéis e novas regras, os quais são definidos pela coletividade. Os resultados apontam que a rede é um espaço participativo de integração e de construção da identidade dos cursos, das áreas de conhecimento e da Universidade. Para que a rede tenha significado para os atores é necessária à existência de elementos que sirvam como elo entre os atores e que justifiquem o trabalho coletivo. A rede torna os atores mais reflexivos e é um espaço de reflexão sobre a Universidade e a atuação docente, desenvolvendo as interações pela lógica do debate. Os participantes utilizam os seus conhecimentos e as experiências para reforçar os discursos, assim como as normas norteiam e justificam as ações dos atores. A rede dá acesso a todos os níveis hierárquicos da organização e a recursos materiais, financeiros, informacionais e de conhecimentos. Portanto, a rede é um ambiente de articulação e legitimação das decisões e das normas organizacionais, dando substancialidade para a organização. Dessa forma, as redes consolidam-se a partir da rotinização das práticas, formando estruturas, construindo uma identidade compartilhada que serve de elemento agregador para o grupo. / This research aims to understand the structuration process of organizational virtual social networks, which are opportunities for collaboration, interaction and sharing of knowledge, ideas and projects. The networks were studied based on the Theory of Structuration, Giddens (2009), highlighting the duality of structure and reflections on the action context (time and space dimensions). This research is a case study performed in a Higher Education Institution, and the analysis units were three organizational virtual social networks, called ‘Forums’. The organization is geographically distributed in 10 campi located in different cities, and the networks have the role to integrate the actors and enable the sharing of experience, assisting in the process of the identity construction of the areas and the University. The Forums aimed to discuss and deliberate on issues related to undergraduate courses at different levels of knowledge. They were characterized by different areas of knowledge and allowed the spontaneous participation of the actors at any time. The investigation was carried out through participant observation, interviews and document analysis. The results show that networks are formed as the groups determine their work objectives, which lead to the definition of a work schedule, resources, roles and structures. Each network has a coordinator responsible for being the mediator and the instigator of the interactions that occur in person and virtually. The virtual tools are determined by the actors based on the activities to be developed, and they may include communication or instrumental technologies such as collaborative text editors. We listed the elements constituent of organizational virtual social network, which are not steady and may change as they change their Forum purposes of action. Therefore, it is clear that at each meeting, when some new goals and tasks are determined, or in the insertion of new members, the network reconfigures itself, reproducing other features, changing its composition, and bringing out new structures, roles and rules, which are defined by the community. The results show that the network is a participative space of integration and identity construction of courses, areas of knowledge and the University. The network is meaningful if the actors identify elements that serve as a link between them and justify the collective work. The network makes the actors more reflective and is a reflection about the University and the teaching practice, developing the interactions by the logic of the debate. Participants use their knowledge and experiences to strengthen the speeches. The norms guide and justify the actions of actors. The network gives access to higher levels of the organization as well as to material, financial, informational, and knowledge resources. Therefore, the network is an environment of articulation and legitimation of decisions and organizational norms, giving substantiality to the organization. Networks are consolidated from the routinization of practices, forming structures and the establishment of a shared identity that serves as an aggregating element to the group.

Les « gels attractifs » constituent une catégorie particulière de fluides complexes. Ces gels sont formés à partir d’une suspension de particules attractives en faible concentration volumique. La microstructure du gel est très facilement modifiée par l’application d’une contrainte. Ainsi, il est possible de structurer ces gels par un cisaillement dans une géométrie suffisamment confinée. Nous avons étudié en détail ce phénomène dans des gels de noirs de carbone ainsi que dans des suspensions de billes de verre dans de l’huile rendues attractives par la présence d’une faible quantité d’eau. Nous avons reproduit ce phénomène dans des simulations numériques de dynamique moléculaire, ce qui permet d’étudier les conditions nécessaires à l’apparition de telles structures. Enfin, en géométrie peu confinée, le mécanisme de rupture et d’écoulement de ces gels en volume est complexe puisque leur rupture est en perpétuelle compétition avec leurcinétique de reformation. Nous avons étudié la rupture des gels de noir de carbone en couplant des techniques classiques de rhéologie avec une technique de mesure locale de déplacement par ultrasons. Ces expériences nous ont permis d’établir un lien entre le comportement global du matériau (sa rhéologie macroscopique) et la dynamique locale de fluidification. / Attractive gels are made of weakly aggregated colloidal particles dispersed in a liquid at lowvolume fraction. Their microstructure can easily be modified when submittedto a shear stress. For instance, those gel can form structures in response to flow under strong confinement. This work is a detailed study of this phenomenon in carbon black gels and in glass beads suspensions in oil made attractive by addition of a small amount water. Those structures are also reproduced in molecular dynamics numerical simulations which allow us to study the conditions for such structures to appear. When sheared in a large gap, yielding and flow of those gels is complex due to the competition between shear-induced aggregation and breakup. Yielding of carbon black gels has been studied by coupling global rheological measurements with local ultrasonic velocimetry providing a link between the global (macroscopic) behaviour and the local dynamics.