Made available in DSpace on 2015-03-05T14:01:21Z (GMT). No. of bitstreams: 0 Previous issue date: 17 / Universidade do Vale do Rio dos Sinos / Este trabalho apresenta o Global uma infra-estrutura descentralizada de educação ubíqua, baseada em sistemas multi-agentes. O Global disponibiliza agentes de software que executam tarefas comuns ao processo de aprendizagem ubíqua. A partir da extensão desses agentes ou adição de novos ele é especializado para a criação de ambientes de educação ubíqua. Além de apresentar a arquitetura geral da infra-estrutura, descrevendo seus agentes e componentes auxiliares, é apresentada a modelagem do Global na metodologia Prometheus, uma metodologia para especificação de sistemas multi-agentes. A dissertação também descreve o protótipo desenvolvido a partir da especificação do Global e apresenta três aplicações desenvolvidas utilizando o protótipo, com finalidade de avaliar o Global. / This work presents Global, a decentralized, ubiquitous learning infrastructure based on multi-agent systems. Global provides software agents that execute tasks related to ubiquitous learning. By extending these agents, or adding new agents, Global can be customized to create ubiquitous learning environments. We present a complete scheme of the general architecture, describing its agents and auxiliary components. We also fully model the system throught the Prometheus methodology, which is used to specify multi-agent systems. We developed a prototype based on the Global specification. Furthermore, we present three applications developed using this prototype, with the goal to perform an evaluation of our approach.

Développer de nouveaux fluorophores ayant une forte section efficace d’absorption à deux photons (ADP) et des propriétés d'émission dans le rouge lointain est important, en particulier pour l’imagerie in-vivo profonde. Cette gamme de longueur d'onde correspond en effet à la fenêtre de transparence optique des tissus. Cette thèse étudie le potentiel de nouveaux fluorophores émettant dans rouge construits sur un noyau fluorène pour la microscopie à deux photons in-vivo, en privilégiant l'imagerie du système vasculaire, d'une part, et la mesure optique de la pression d'oxygène dissous, d'autre part.Ainsi, une famille de chromophores asymétriques a été conçue et synthétisée. La plupart des chromophores présentent une forte émission dans le proche IR, induite par l'agrégation. De plus, une stratégie de co-protection basée sur un système micellaire / silice a été utilisé pour préparer des nanoparticules avec un intérieur apolaire et conserver les propriétés optiques des chromophores dipolaires en solution aqueuse. Des mesures de fluorescence excitée à deux photons ont été menées en solvant organique et en suspension aqueuse. Les agrégats et les nanoparticules ont été utilisés avec succès en imagerie biphotonique du système vasculaire sur petit animal en utilisant un modèle de tumeur à l'intérieur de la peau de l'oreille de la souris. Les nanoparticules de silice montrent une coloration exceptionnelle du système vasculaire qui en fait de parfaits marqueurs du système vasculaire.Dans un deuxième temps, quatre nouveaux chromophores, absorbant à deux photons, ont été synthétisés et leurs propriétés photo physiques à un et à deux photons ont été étudiées. Le chromophore le plus adapté a ensuite été greffé de manière covalente par chimie click, à un complexe de palladium avec un ligand porphyrine, cœur phosphorescent dont l’émission est sensible à la présence d’oxygène. Deux composés contenant quatre ou huit absorbeur à deux photons ont été obtenus et étudiés. Les résultats démontrent que l'incorporation d'un chromophore ADP approprié peut effectivement augmenter les propriétés d’ADP du système, ce qui permet une sensibilité efficace vis-à-vis de l'oxygène. / The development of fluorophores with efficient two-photon absorption (TPA) and emission properties in the far red/NIR is important, especially for in depth in-vivo optical imaging as this wavelength range corresponds to the optical transparency window of tissues. This thesis investigates the potential of new red emitting fluorophores containing a fluorene ring for in-vivo two-photon microscopy focusing on vascular imaging on one hand and on oxygen pressure measurement on the other hand.A new series of asymmetrical fluorene-based chromophores were designed and synthesized. Their structure-property relationships were systematically investigated. It was found that most of chromophores exhibit aggregation-induced emission behaviors in the NIR region. In addition, a micelle/silica coprotection strategy was proposed to prepare nanoparticles with a less polar interior, which can be used to conserve optical properties of dipole chromophores in aqueous solution. The two-photon excited fluorescence (TPEF) measurements indicate that they all display obvious TPA activities in organic solvent and aqueous suspension. Both the NIR-emissive aggregates and nanoparticles have been successfully used for TPEF imaging of blood vessels inside mouse ear skin. The silica nanoparticles show outstanding staining of the vascular system making them perfect blood pool markers.On a second part, four new fluorene-based two-photon absorbing chromophores have been synthesized and their one- and two-photon photophysical properties were investigated. The optimum chromophore was successfully attached covalently to an oxygen responsive phosphorescent Pd-porphyrin complex by click chemistry. Two new compounds contain four or eight TPA chromophores donor connected to the phosphorescent core. The result demonstrate that the incorporation of a suitable TPA chromophore can effectively enhance the TPA of the system, allowing efficient sensitivity towards oxygen.

Nous avons initialement réalisé une étude prospective évaluant l’intérêt de la TEP-TDM au FDG pour le diagnostic de récidive infra-clinique des carcinomes épidermoïdes des voies aéro-digestives supérieures. Nos résultats ont montré d’excellentes performances de l’examen en surveillance systématique, permettant notamment le diagnostic de récidive chez environ 1/3 des patients cliniquement asymptomatiques 1 an après la fin du traitement. Nous avons ensuite étudié le bénéfice d’une évaluation thérapeutique précoce par TEP-TDM au FDG à 2 cures d’une chimiothérapie néoadjuvante par TPF précédant une radiochimiothérapie sur une cohorte de sujets porteurs d’un cancer localement avancé (stade IIIIVA). Nos résultats ont montré une corrélation statistiquement significative entre la réponse métabolique et la survie sans récidive, suggérant l’intérêt d’un examen intermédiaire pour cibler de façon précoce les patients réfractaires au traitement. Nous avons ensuite analysé prospectivement l’impact pronostique de la TEP-TDM au FDG réalisée en situation préthérapeutique dans le but de sélectionner encore plus précocement cette population à risque de récidive. Les résultats de nos 2 études ont prouvé que l’utilisation de paramètres volumétriques ou cinétiques de la captation intra-tumorale du FDG était prédictive de la survie globale, avec une valeur pronostique indépendante et supérieure à celle du SUVmax. Cette thèse ouvre ainsi des perspectives de nouvelles indications de la TEP-TDM au FDG dans la prise en charge des carcinomes épidermoïdes des VADS, soulève des problématiques de recherche avec notamment l’émergence des nouveaux traceurs permettant de caractériser au mieux la cellule tumorale et s’inscrit dans une volonté actuelle d’une médecine préventive et prédictive personnalisée. / We initially conducted a prospective study evaluating diagnostic interest of FDG PET-CT for head and neck squamous cell carcinomas subclinical recurrence. Our results showed FDG PET-CT high performance in systematic monitoring, especially for the diagnosis of recurrence in about one third of clinically asymptomatic patients 1 year after the end of treatment. Secondly, we studied the benefits of early treatment evaluation by FDG PET-CT after 2 cycles of neoadjuvant chemotherapy by DCF (docetaxel, cysplatin, 5-fluorouracil) before chemoradiotherapy in a cohort of patients with locally advanced cancer (stage III-IVA). Our results showed a statistically significant correlation between metabolic tumor response and recurrence-free survival, suggesting the interest of an interim PETscan to early target patients refractory to treatment. Then, we prospectively analyzed the prognostic impact of FDG PET-CT performed at initial staging in order to select earlier this population at risk for recurrence. The results of our two studies proved that the use of volumetric or kinetic parameters of intratumoral FDG uptake was predictive of overall survival, with an independent prognostic value and a higher performance to SUVmax. Thus, this thesis opens new perspectives indications of FDG PET-CT in the management of head and neck squamous cell carcinoma, raises research issues such as the emergence of new tracers to characterize at best the tumor cell and falls within a current commitment to move towards a personalized preventive and predictive medicine.

Submitted by Fernanda Ciolfi (fernanda.ciolfi@puc-campinas.edu.br) on 2016-08-11T13:11:54Z No. of bitstreams: 1 Jo?o Paulo Coelho.pdf: 2583131 bytes, checksum: 2bd7fac9f5b05dee931c7c7819a4348a (MD5) / Made available in DSpace on 2016-08-11T13:11:54Z (GMT). No. of bitstreams: 1 Jo?o Paulo Coelho.pdf: 2583131 bytes, checksum: 2bd7fac9f5b05dee931c7c7819a4348a (MD5) Previous issue date: 2016-06-03 / The high rate of global population growth of recent decades has been concentrated in large urban centers. As a result of such growth it is observed that the occupation of these urban areas often occurs in a disorderly manner and without planning, especially as regards the provision of suitable urban infrastructure systems; imposing the population a low quality of life. Thus, this work was intended to evaluate the quality of life in the city of Campinas adapting the method of evaluation of environmental impact of Battelle Columbus. The determination of quality of life indicators is a fundamental tool to direct public actions in the pursuit of sustainability in urban areas. In developing the work objective indicators were used to obtain as a result the outlook on the quality of life in the city. The application and considered indicators chosen method is obtained for the city of Campinas a classification considered Bad as regards the quality of life. / A alta taxa de crescimento populacional mundial das ?ltimas d?cadas tem-se concentrado em grandes centros urbanos. Como resultado de tal crescimento observa-se que a ocupa??o dessas ?reas urbanas muitas vezes se d? de forma desordenada e com planejamento inadequado, especialmente no que se refere ao provimento de sistemas de infraestrutura urbana adequados; impondo ? popula??o uma baixa qualidade de vida. Assim, com este trabalho, pretendeu-se avaliar a qualidade de vida do munic?pio de Campinas adaptando o m?todo de avalia??o de impacto ambiental de Battelle Columbus. A determina??o de indicadores de qualidade de vida ? ferramenta fundamental para direcionar a??es p?blicas na busca da sustentabilidade das ?reas urbanas. No desenvolvimento do trabalho foram utilizados indicadores objetivos para obter-se como resultado o panorama relativo a qualidade de vida na cidade. Da aplica??o do m?todo escolhido e dos indicadores considerados obteve-se para o munic?pio de Campinas uma classifica??o final considerada Ruim no que se refere a qualidade de vida.

Submitted by Fernanda Ciolfi (fernanda.ciolfi@puc-campinas.edu.br) on 2016-08-11T14:09:31Z No. of bitstreams: 1 OSVALDO PISSOLATO JR.pdf: 2291678 bytes, checksum: e7217ede7cd8cccdee8affcb06011624 (MD5) / Made available in DSpace on 2016-08-11T14:09:31Z (GMT). No. of bitstreams: 1 OSVALDO PISSOLATO JR.pdf: 2291678 bytes, checksum: e7217ede7cd8cccdee8affcb06011624 (MD5) Previous issue date: 2016-06-06 / Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo - FAPESP / The large disposal of construction waste, due to the renovations and demolitions as well as the waste generated by the low quality of labor, makes the construction industry one of the major polluters of the environment. In recent decades, comes to forcing organized gathering of rubble and its recycling through the enforcement of environmental laws, so that the construction industry there have disciplining towards self-manage their disposal. Studies have been intensifying to rethink the reuse of construction waste, through the recycling process, to develop standards for production, evaluation and use of recycled aggregates in order to increase their consumption, making it economically feasible to produce. This research assumes that the fine aggregate derived from the crushing of construction and demolition waste can replace the natural fine aggregate in the production of mortars for coatings. However, the issue that was faced was to what extent it would be possible to replace these materials so that the result in practice was technically and economically feasible, thereby increasing the chance of use of these recycled aggregates. In order to analyze the influence of fine aggregates derived from civil construction waste (CCW), replacing fine aggregate in the production of hydraulic and mixed mortars for wall coverings and ceilings, we used the experimental methodology to verify the influence of fines content of recycled aggregate in the mortar properties in fresh and hardened state. The prepared mortars were also classified according to NBR 13281: 2005 and evaluated for adhesion, cracking and permeability after application on masonry of concrete blocks. Therefore, we chose to study the replacement of natural aggregate by the CCW in rates of 30%, 60% and 100%, in proportions of admixture and mixed hydraulic mortar, whose purpose would be to apply as monolayer coating mortar. As analysis and discussion of the results could be seen that, in tests, both plastic and hardened state, the mortar produced with recycled aggregate, the three mixing ratios in the study had a satisfactory performance in relation to admixture reference. However, the results were not satisfactory in applicability tests, since its performance was below the minimum rate set by the standard. The results, however, suggest referral to further studies in order to continue rethinking the paradigm of industrial production so that it is founded on a model of sustainable development in favor of environmental preservation. / O grande descarte de rejeitos da constru??o civil, em fun??o das reformas e demoli??es como tamb?m do desperd?cio gerado pela baixa qualidade da m?o de obra, faz da ind?stria da constru??o civil uma das grandes poluidoras do meio ambiente. Nas ?ltimas d?cadas, vem-se obrigando o recolhimento organizado dos entulhos e sua reciclagem por meio da imposi??o das leis ambientais, de modo que a constru??o civil, paulatinamente, tem-se disciplinando no sentido de autogerir os seus descartes. Estudos v?m se intensificando com o objetivo de se repensar o reaproveitamento dos res?duos da constru??o civil, por meio do processo de reciclagem, no sentido de desenvolver normas para produ??o, avalia??o e utiliza??o dos agregados reciclados, de modo a aumentar seu consumo, tornando economicamente vi?vel a sua produ??o. Esta pesquisa parte do pressuposto de que o agregado mi?do proveniente da britagem de res?duo de constru??o e demoli??o pode substituir o agregado mi?do de origem natural na produ??o de argamassas para revestimentos. Todavia, a quest?o com a qual se deparava era at? que ponto seria poss?vel fazer a substitui??o destes materiais de modo que o resultado na pr?tica fosse vi?vel t?cnica e economicamente, aumentando assim, a chance de emprego desses agregados reciclados. Com o objetivo de analisar as influ?ncias dos agregados mi?dos oriundos dos res?duos de constru??o civil (RCC), em substitui??o ao agregado mi?do natural na produ??o de argamassas hidr?ulica e mista para revestimentos de paredes e tetos, empregou-se a metodologia experimental para verificar a influencia do teor de finos do agregado reciclado nas propriedades das argamassas no estado fresco e endurecido. As argamassas preparadas tamb?m foram classificadas conforme a NBR 13281:2005 e avaliadas quanto a ader?ncia, fissura??o e permeabilidade ap?s aplica??o em alvenaria de bloco. Para tanto, optou-se por estudar a substitui??o do agregado natural pelo de RCC nas propor??es de 30%, 60% e 100%, em propor??es de mistura de argamassa mista e hidr?ulica, cuja finalidade seria a aplica??o como embo?o paulista. Conforme an?lise e discuss?o dos resultados p?de-se constatar que, nos ensaios, tanto no estado pl?stico quanto no estado endurecido, as argamassas produzidas com reciclado, nos tr?s tra?os em estudo, tiveram um desempenho satisfat?rio, em rela??o ao tra?o refer?ncia. Entretanto, os resultados n?o foram satisfat?rios nos ensaios de aplicabilidade, visto que sua performance ficou abaixo do ?ndice m?nimo estabelecido pela norma. Os resultados, todavia, sugerem encaminhamento para novos estudos no sentido de continuar repensando o paradigma da produ??o industrial para que este seja alicer?ado num modelo de desenvolvimento sustent?vel favor?vel ? preserva??o ambiental.

Submitted by Fernanda Ciolfi (fernanda.ciolfi@puc-campinas.edu.br) on 2016-08-12T18:10:18Z No. of bitstreams: 1 Wando Roberto Trentin.pdf: 2886501 bytes, checksum: f29c34d3f59deacdcef391203fdd9c33 (MD5) / Made available in DSpace on 2016-08-12T18:10:18Z (GMT). No. of bitstreams: 1 Wando Roberto Trentin.pdf: 2886501 bytes, checksum: f29c34d3f59deacdcef391203fdd9c33 (MD5) Previous issue date: 2016-06-24 / This paper presents the diagnosis of urban infrastructure of the Santo Antonio de Posse / SP, with emphasis on aspects related to economic, environmental and social. It made state literature review of the art of planning concepts applicable to urban infrastructure systems. The detailed diagnosis is the main premise of the methodology, covering the topics of use and occupation, sanitation, urban mobility, environment and telecommunications. The Plan county Director served as a starting point to identify, through the intersection of the data collected, the evaluation of guidelines and strategies proposed in the medium and long term. The diagnosis led to the development of considerations in the context of prospective evaluations, which served to outline the expected product, which is the region's sustainable development and territorial planning in urban and rural levels. / Este trabalho apresenta o diagn?stico da infraestrutura urbana do Munic?pio de Santo Ant?nio de Posse/SP, com ?nfase nos aspectos relacionados a sustentabilidade econ?mica, ambiental e social. ? feita revis?o bibliogr?fica do estado da arte dos conceitos de planejamento aplic?veis aos sistemas de infraestrutura urbana. O diagn?stico detalhado ? a principal premissa da metodologia utilizada, abrangendo os t?picos de uso e ocupa??o do solo, saneamento b?sico, mobilidade urbana, meio ambiente e telecomunica??es. O Plano Diretor do munic?pio serviu como ponto de partida para identificar, atrav?s do cruzamento dos dados coletados, a avalia??o das diretrizes e estrat?gias propostas a m?dio e longo prazo. O diagn?stico propiciou a elabora??o de considera??es no ?mbito das avalia??es prospectivas, que serviram para delinear o produto esperado, que ? o desenvolvimento sustent?vel da regi?o e seu ordenamento territorial, nos n?veis urbano e rural.

A infra-estrutura existente no Brasil, assim como em diversos outros países de economia emergente, é geralmente caracterizada pela ineficiência e pela qualidade inferior dos serviços em comparação a serviços semelhantes prestados por entidades do setor privado. Além disso, o setor público notadamente possui restrições orçamentárias, cujos efeitos incluem a desistência de projetos e postergação de investimentos de grande importância para a sociedade. Esse contexto acaba por limitar o desenvolvimento sócio-econômico do País, visto que reduz ou mesmo inibe a criação de vantagens competitivas nos mais diversos setores da economia. Dessa forma, nota-se a necessidade de adoção de novas formas de contratação e prestação de serviços que permitam inovações e soluções alternativas a tal problema. Dentro desse contexto, surge a Parceria Público-Privada como um instrumento que reconhece as habilidades e capacitações, tanto do setor privado quanto do setor público, com o intuito de se obter parcerias que gerem as maiores sinergias possíveis entre as partes. Internacionalmente, esse tipo de parceria tem sido utilizado há algum tempo, havendo diversas experiências bem-sucedidas em países europeus como Inglaterra, Irlanda, Portugal, Austrália, Canadá, EUA e Chile. No Brasil, o tema é recente, tendo em vista as datas de aprovação das leis federal e estaduais referentes ao assunto e a não-existência de projetos implantados sob essa forma de parceria. No entanto, percebe-se um elevado interesse, tanto por parte do setor público como por parte de entidades do setor privado, de utilizar esse instrumento em prol da melhoria da infra-estrutura do País. Atualmente, há no País três projetos em fase avançada de implantação, a saber: um projeto de transporte metroviário no Estado de São Paulo (Projeto da Linha 4 do Metrô de São Paulo), um projeto de transporte rodoviário no Estado de Minas Gerais (Projeto da Rodovia MG-050) e um projeto de saneamento básico no Estado da Bahia (Projeto do Sistema de Disposição Oceânica do Jaguaribe). Nesses casos, há editais de licitação publicados, sendo o objetivo dos três governos estaduais envolvidos a escolha e o início da operação da PPP ainda este ano. Tendo em vista a grande polêmica em torno do tema e os potenciais efeitos desse instrumento para a infra-estrutura do País, é importante verificar se esses primeiros projetos estão sendo implantados conforme os princípios internacionais estabelecidos em experiências semelhantes bem-sucedidas, já que isso minimiza a ocorrência de determinados erros de implantação que incorram em custos adicionais. Dessa forma, o presente trabalho se propõe a analisar como se deu a estruturação de dois desses três projetos: o Projeto-Piloto de PPP da Rodovia MG-050 e o Projeto-Piloto de PPP do Sistema de Disposição Oceânica do Jaguaribe. Ressalta-se que o intuito desta análise é a verificação da presença dos princípios das PPPs bem-sucedidas em experiências internacionais semelhantes. Contudo, isso não implica necessariamente o sucesso das primeiras experiências em PPPs no Brasil. Procura-se então minimizar a probabilidade de insucesso a partir de uma implantação adequada dos princípios das PPPs para que, no futuro, quando tais projetos estiverem em plena operação, seja possível verificar se as PPPs estão atendendo às expectativas da sociedade e se realmente representam inovações e a melhor forma de estruturação para os projetos analisados. / The infra-structure existing in Brazil, like in other developing economy countries, is usually characterized by its inefficiency and poor quality of its services in comparison to similar services provided by private sector entities. Besides, the public sector clearly has budget restrictions which effects include the desistance of projects and the postponement of relevant investments for society. This context ends up restricting the socio-economic development of a country since it reduces or even inhibits the creation of competitive advantages in many different industries. Therefore, one can realize the necessity of adopting new forms of procurement that allow innovation and alternative solutions for this problem. Considering those circumstances the Public-Private Partnership comes as an instrument that recognizes the abilities both from the private sector and the public sector with the objective of achieving partnerships that create the greatest sinergies between the parties. Internationally, this kind of partnership has been used for a long time and there are many successful experiences in European countries such as England, Ireland and Portugal, Australia, Canada, USA and Chile. In Brazil, the subject is recent considering the approval dates of federal and state laws regulating it and the absence of on-going projects under this form of procurement, nevertheless, one can notice that there is a lot of interest both from the public sector and entities from private sector on the use of this instrument on behalf of the improvement of the infra-structure in this country. Nowadays, there are three projects in Brazil in the bidding stage: a subway project in the state of São Paulo (Line 4 of São Paulo Subway Project), a road project in the state of Minas Gerais (Road MG-050 Project) and a sanitation project in the state of Bahia (Jaguaribe System of Oceanic Disposal Project). In all of these cases there are published biddings and the goal of all of these three state governments is to put the partnership into operation this year. Considering the intense discussion around this subject and the potential effects of this instrument to the infra-structure of this country it is important to find out if these first PPP projects are being implemented according to the established international principles for successful PPPs, since by doing this one can minimize the occurrence of certain mistakes which consequently provoke additional costs. Therefore, this study offers an analysis of how was the structuring of two out of the three existing projects in Brazil: the Road MG-050 Project and the Jaguaribe System of Oceanic Disposal Project. One should stand out that the main objective of this analysis is the examination of the presence of successful PPP principles noted in similar international experiences, but this does not necessarily imply in the success of these first experiences in PPP in Brazil. The idea is to minimize the probability of failure by an adequate implementation of the PPP principles, so, in the future, when these projects will be on a on-going basis, it will be possible to verify if the PPPs are meeting the expectations and if they really represent innovation and the best form of procurement for the analyzed projects.

Ce travail de thèse porte sur l'étude par spectrophotométrie de phénomènes de couplage entre un émetteur photonique discret et une cavité optique dont les propriétés sont adaptées à l'émetteur. Nous nous sommes intéressés à l'interaction de boîtes quantiques semiconductrices InAs/GaAs avec des microcavités optiques dont la géométrie originale diffère selon les propriétés dont on veut tirer partie. Ainsi, nous partirons de la fabrication de ces systèmes par épitaxie par jets moléculaires, pour nous focaliser sur trois grands types de microcavités, dont nous décrirons à la fois les étapes de fabrication, mais aussi les études optiques réalisées par spectrophotométrie Infra-rouge. Ainsi, les microdisques reportés sur saphir par collage moléculaire ont montré un important potentiel pour la réalisation de microlasers, grâce à de très bonnes propriétés de dissipation thermique. Sur les micropiliers à miroirs de Bragg, nous avons expérimentalement montré pour la première fois la co-existence de modes de galerie et de modes de micropiliers, ainsi que la possibilité d'exploiter l'effet laser sur ces modes, ce qui ouvre de nouvelles perspectives en termes de systèmes photoniques. Nous avons également développé une technique originale et reproductible de métallisation à l'or des flancs et démontré son innocuité sur les propriétés optiques de ces modes, ce qui permet d'envisager son application à d'autres dispositifs. Enfin, nous terminons par la fabrication et l'étude de nano-fils photoniques à boîtes quantiques uniques, dont les capacités prometteuses permettent de conclure à une concurrence sérieuse vis-à-vis des micropiliers en tant que source de photon unique.

Les hydrates de ciment (C-S-H) obtenus par dissolution/précipitation du ciment anhydre, constituent la matrice donnant au matériau ses propriétés mécaniques et sont structurellement analogues de la tobermorite, un calcio-silicate lamellaire naturel. La compréhension de la cohésion du ciment passe donc par la compréhension de la cohésion entre feuillets tobermoritiques. La structure lamellaire de différents échantillons de CSH tobermoritiques synthétisés par "chimie douce" a été mise en évidence ; les échantillons avec un rapport Ca/Si égal à 0.9 étant particulièrement bien cristallisés. L'étude du processus de déshydratation pour ces échantillons a permis d'identifier 3 phases et de montrer la similarité de comportement vis à vis du "vrai" ciment. Nous montrons que la transition 14-11 Å est irréversible. Se pose alors la question du rôle de l'eau interfoliaire dans la cohésion du matériau en relation avec les deux structures possibles décrites dans la littérature pour la tobermorite naturelle 11 Å : la proposition d'Hamid (1981) décrivant un ensemble de feuillets indépendants et celle de Merlino et al (1999) décrivant des feuillets chimiquement liés. La confrontation entre résultats expérimentaux (29Si-RMN et spectroscopie infra-rouge) et numériques (calculs ab-initio et minimisation d'énergie) indique que la structure d'Hamid est un modèle acceptable pour les C-S-H tobermoritiques. La nature des liaisons inter-feuillets est d'origine coulombienne au sens de l'énergie de réseau des solides ioniques.

Les enjeux actuels pour la valorisation de dérivés de la biomasse donnent à la catalyse hétérogène basique un intérêt nouveau. Dans la mesure où des relations complexes peuvent exister entre la performance d'un catalyseur hétérogène basique et sa force déprotonante, une étude des critères qui influencent la réactivité des solides dans des réactions modèles de basicité et dans une réaction modèle de transestérification a été entreprise. Il apparaît que les réactions faisant intervenir des réactifs faiblement acides (dans notre cas, un alcène), ne peuvent être réalisées que sur des sites qui peuvent interagir fortement avec les acides de Brønsted. Ces sites ne peuvent pas être caractérisés par la force de leur interaction avec une sonde CO2, car nous avons montré que les échelles de basicité selon Lewis et selon Brønsted étaient différentes. En revanche, dans le cas de réactions faisant intervenir des acides plus forts, tels des alcools, plusieurs facteurs sont à considérer. Par exemple, dans la catalyse de la transestérification, la présence de sites pouvant réagir selon une voie acide peut augmenter la puissance catalytique des solides. Par ailleurs, cette étude a permis de dégager des tendances générales sur la structure et la réactivité basique de l'oxyde de magnésium en fonction de son recouvrement en adsorbats hydroxyles et carbonates. Quatre types de carbonates adsorbés ont pu être identifiés, ce qui a permis de mettre en évidence la formation de plans (110) après certains prétraitements. Ces plans, très réactifs, sont particulièrement intéressants pour la catalyse hétérogène basique.