No / Advances in micromoulding technology are now allowing mass production of complex, three-dimensional functional products having sub-milligram masses and carefully tailored surface finishes. In order to create a viable manufacturing process for these components, accurate process monitoring and product evaluation are essential in order to highlight process problems and production of substandard parts. The present study describes work implementing a suite of sensors on a commercial micromoulding machine for detailed process interrogation. Evaluation of demoulded products is performed with a single camera based system combined with custom software to allow for three-dimensional characterisation of products during the process.

No / The effect of matrix polymer and filler content on the rheological behavior of hydroxyapatite-filled injection molding grade high-density polyethylene (HDPE) has been studied. Studies of the flow curves revealed that the matrix and the composite exhibit three distinct regions in the flow curve, namely, a pseudoplastic region at low to moderate shear rates, a plateau and a second pseudoplastic region at high shear rates. The shear stress corresponding to the plateau (Tc) is dependent on both the filler concentration and the melt temperature. Addition of HA in the HDPE matrix increases the value of Tc and decreases compressibility of the melt. An increase in temperature also raises the value of Tc. From the nature of flow curves it is concluded that the matrix polymer largely decides the rheology of the composite.

L’objectif de ce mémoire de maîtrise est de développer des outils de diagnostics non-invasifs et de caractériser in-situ les dérives de procédé dans un réacteur industriel utilisé en production pour la gravure profonde du silicium par le procédé Bosch. Ce dernier repose sur l’alternance d’un plasma de SF6 pour la gravure isotrope du Si et d’un plasma de C4F8 pour la passivation des parois dans l’optique d’obtenir des tranchées profondes et étroites. Dans un premier temps, nous avons installé une sonde courant-tension sur la ligne de transmission du signal rf au porte-substrat pour l’étude de son impédance caractéristique et un spectromètre optique pour l’étude de l’émission optique du plasma. Nos travaux ont montré que l’évolution temporelle de l’impédance constitue un excellent moyen pour identifier des changements dans la dynamique du procédé, notamment une gravure complète de la photorésine. De plus, à partir des spectres d’émission, nous avons pu montrer que des produits carbonés sont libérés du substrat et des parois lors de l’alternance passivation/gravure et que ceux-ci modifient considérablement la concentration de fluor atomique dans le plasma. Dans un second temps, nous avons développé un réacteur à « substrat-tournant » pour l’analyse in-situ des interactions plasma-parois dans le procédé Bosch. Nos travaux sur ce réacteur visaient à caractériser par spectrométrie de masse l’évolution temporelle des populations de neutres réactifs et d’ions positifs. Dans les conditions opératoires étudiées, le SF6 se dissocie à près de 45% alors que le degré de dissociation du C4F8 atteint 70%. Le SF6 est avant tout dissocié en F et SF3 et l’ion dominant est le SF3+ alors que le C4F8 est fragmenté en CF, CF3 et CF4 et nous mesurons plusieurs ions significatifs. Dans les deux cas, la chaîne de dissociation demeure loin d’être complète. Nous avons noté une désorption importante des parois de CF4 lors du passage du cycle de passivation au cycle de gravure. Un modèle d’interactions plasmas-parois est proposé pour expliquer cette observation. / The purpose of this master thesis is to develop non-invasive diagnostic tools for in-situ characterization of process drifts in an industrial reactor used in production for deep silicon etching by the Bosch process. This process alternates between a SF6 plasma for isotropic Si etching and a C4F8 plasma for sidewall passivation to achieve deep and narrow trenches. In this context, a current-voltage probe was installed on the rf transmission line to the substrate holder for impedance studies and an optical spectrometer for plasma optical emission spectroscopy. We have shown that the time evolution of the impedance represents an excellent tool for monitoring changes in the process dynamics, including the complete removal of the photoresist due to process drifts. In addition, based on emission spectroscopy, we have demonstrated that carbon products are released from the substrate and reactor walls during etching. A « spinning-wall » reactor was also developed for in-situ analysis of plasma-wall interactions. The main objective of our work on this reactor was to characterize the time evolution of the population of reactive neutrals and positive ions by plasma sampling mass spectrometry. Over the range of experimental conditions investigated, the percent dissociation of SF6 was 45%, while the one of C4F8 was 70%. SF6 was mostly dissociated in F and SF3, with SF3+ as the dominant ion. C4F8 is essentially fragmented in CF, CF3 and CF4 with many significant ions. In both cases, the dissociation chain remained incomplete. An important desorption of CF4 from the reactor walls was observed when going from passivation to etching cycles. A plasma-wall interaction model was proposed to explain such observation.

Made available in DSpace on 2014-12-17T15:41:46Z (GMT). No. of bitstreams: 1 StevieHLpdf.pdf: 1475886 bytes, checksum: e83c49569bddebb612701e2de7e607bc (MD5) Previous issue date: 2009-08-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In last years it has talked a lot about the environment and the plastic waste produced and discarded. In last decades, the increasing development of research to obtain fuel from plastic material, by catalytic degradation, it has become a very attractive looking, as these tailings are discarded to millions worldwide. These materials take a long time to degrade themselves by ways said natural and burning it has not demonstrated a viable alternative due to the toxic products produced during combustion. Such products could bring serious consequences to public health and environment. Therefore, the technique of chemical recycling is presented as a suitable alternative, especially since could be obtain fractions of liquid fuels that can be intended to the petrochemical industry. This work aims to propose alternatives to the use of plastic waste in the production of light petrochemical. Zeolites has been widely used in the study of this process due to its peculiar structural properties and its high acidity. In this work was studied the reaction of catalytic degradation of high-density polyethylene (HDPE) in the presence HZSM-12 zeolites with different acid sites concentrations by thermogravimetry and pyrolysis coupled with GC-MS. The samples of the catalysts were mixed with HDPE in the proportion of 50% in mass and submitted to thermogravimetric analyses in several heating rates. The addition of solids with different acid sites concentrations to HDPE, produced a decrease in the temperature of degradation of the polymer proportional the acidity of the catalyst. These qualitative results were complemented by the data of activation energy obtained through the non-isothermal kinetics model proposed by Vyazovkin. The values of Ea when correlated to the data of surface acidity of the catalysts indicated that there is a exponential decrease of the energy of activation in the reaction of catalytic degradation of HDPE, in function of the concentration of acid sites of the materials. These results indicate that the acidity of the catalyst added to the system is one of the most important properties in the reaction of catalytic degradation of polyethylene / Nos ?ltimos anos tem-se falado muito sobre o meio ambiente e sobre o lixo pl?stico produzido e descartado. Nas ?ltimas d?cadas, o crescente desenvolvimento de pesquisas com o intuito de obter combust?veis a partir de material pl?stico, via degrada??o catal?tica, tem-se tornado uma busca muito atrativa, j? que esses rejeitos s?o descartados aos milh?es em todo mundo. Esses materiais levam muito tempo para se degradar por meios ditos naturais e sua incinera??o n?o tem se demonstrado uma alternativa vi?vel devido aos produtos t?xicos produzidos durante sua combust?o. Tais produtos conseq?entes poderiam trazer s?rios problemas de sa?de p?blica e ambiental. Logo, a t?cnica da reciclagem qu?mica apresenta-se como uma alternativa adequada, inclusive porque podemos obter fra??es leves do petr?leo que podem ser destinadas ao setor petroqu?mico. Este trabalho tem como objetivo propor alternativas para o aproveitamento de lixo pl?stico na produ??o de combust?veis l?quidos. Ze?litas tem sido amplamente utilizada no estudo desse processo devido ?s suas propriedades estruturais peculiares e sua alta acidez. Neste trabalho, investigou-se a rea??o de degrada??o de Polietileno de Alta Densidade (PEAD) na presen?a de HZSM-12, com diferentes concentra??es de s?tios ?cidos, atrav?s da termogravimetria e pir?lise acoplada ? cromatografia ? g?s e ao espectr?metro de massa (Py-GC-MS). As amostras de catalisadores foram misturadas com PEAD na propor??o de 50% em massa e submetidas a an?lises em diferentes taxas de aquecimento. A adi??o de catalisadores com diferentes concentra??es de s?tios ?cidos produziu uma diminui??o na temperatura de degrada??o do pol?mero proporcional ? acidez do catalisador. Estes resultados qualitativos foram complementados por dados da energia de ativa??o (Ea) obtidos atrav?s do modelo cin?tico n?o-isot?rmico proposto por Vyazovkin. Os valores das Ea quando correlacionados com os dados da acidez superficial dos catalisadores, indicaram que h? uma redu??o exponencial da Ea da rea??o catal?tica de degrada??o em fun??o da concentra??o dos s?tios ?cidos dos materiais, indicando que esta propriedade ? significativa neste tipo de rea??o

Les matériaux ferroélectriques sont caractérisés par l'existence d'une polarisation électrique spontanée, dont l'orientation peut être inversée par l'application d'un champ électrique adéquat. Permettant de coder l'information sous la forme d'un domaine ferroélectrique, i.e. une région du matériau avec une certaine orientation de la polarisation, les ferroélectriques ouvrent la voie au stockage de masse de très haute densité (>10 Tbit/in ²). Dans ce contexte, nous avons employé la Piezoresponse Force Microscopy (PFM), un mode particulier de Microscope à Force Atomique (AFM), permettant la manipulation et la détection des domaines ferroélectriques à l'échelle du nanomètre. Avec pour objectif d'étudier les mécanismes de formation des domaines par l'intermédiaire d'une pointe AFM, nos travaux ont mis en valeur la cinétique de croissance des domaines dans des films minces monocristallins de LiTaO3, avec une approche complémentaire de celle thermodynamique, dépendante du champ électrique et soulignant le rôle de l'humidité dans une possible conduction de surface. En parallèle, les films de LiTaO3 ont permis d'appréhender davantage la nature électro-mécanique de la réponse PFM, pour notamment relier l'amplitude du signal mesuré à la géométrie du domaine sous pointe. PFM et domaines ferroélectriques se sont en effet révélés tour à tour, objet d'étude et outil de caractérisation. / Ferroelectric materials are characterized by their spontaneous polarization, whose direction can be reversed by the application of a suitable electric field. Using domains, i.e. regions of uniform polarization orientation, as information bits, ferroelectrics opens the pathway towards ultrahigh storage densities (>10 Tbit/in²). In this respect, Piezoresponse Force Microscopy (PFM), a technique derived from Atomic Force Microscopy (AFM), was used to manipulate and detect ferroelectric domains on the nanometer scale. Our study was focused on the domains formation mechanism in the local electric field of a nanosized tip. Within an approach complementary to the thermodynamic one, we underlined the kinetics of domains growth in single-crystal LiTaO3 thin films, and the role of humidity in a possible surface conduction. In parallel, the LiTaO3 thin films were used to better understand the PFM response, in particular the relation between the measured signal and the geometry of the domain below the tip. This way, PFM and ferroelectrics domains alternately appeared as object of study and characterization tool.

No description available.

The objective of my work was to develop HDPE clay nanocomposites for packaging with superior barrier (gas and water) properties by economical processing technique. This work also represents a comparative study of thermoplastic nanocomposites for packaging based on linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and Nylon12. In this study properties and processing of a series of linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and Nylon 12 nanocomposites based on Na-MMT clay and two different aspect ratio grades of kaolinite clay are discussed.

O presente trabalho foi desenvolvido para avaliar o potencial de utilização de um reator anaeróbico fabricado em PEAD Polietileno de Alta Densidade, produzido pelo processo de rotomoldagem em substituição aos reatores convencionais construídos em concreto e alvenaria, trabalhando em regime de batelada e enterrados no solo. Os estados de tensões e deformações foram avaliados utilizando o programa de Elementos Finitos ABAQUS versão 6.5 e a malha dos nós utilizando o programa MSC PATRAN 2005 formando 7329 nós e 2004 elementos, em uma malha otimizada para as regiões de maior curvatura (pontos concentradores de tensão). O carregamento é formado com uma pressão interna do biogás de 5 kPa acrescido da carga hidrostática de biomassa de 6000 kgf em uma fundação elástica calculada pela razão tensão/recalque a partir do Módulo de Elasticidade equivalente do solo (Esolo). Comparando o estado de tensões avaliado durante o carregamento foi possível constatar que a maior tensão obtida no elemento mais crítico para a utilização mais provável do reator atingiu o valor de 7,46 MPa (não supera 40% do menor valor de resistência à tração e ao cisalhamento do PEAD de 20 MPa) e a maior razão de deformação dR/R foi de 1.0%. O caso mais crítico avaliado foi quando o reator está enterrado, totalmente vazio, em solo com Esolo = 1,55 MPa e o material com EPEAD = 1550 MPa e com uma sobrecarga superficial no terreno de 20kN/m2 gerando uma tensão de 17,80 MPa no elemento 1955 (atingindo 89% do menor valor de resistência à tração e ao cisalhamento do PEAD igual a 20 MPa). Os resultados obtidos comprovam que o reator produzido em PEAD substitui com vantagens os modelos fabricados em concreto ou alvenaria, suportando a pressão interna do biogás e a carga de biomassa. / The present work was developed to evaluate the potential of uses of an anaerobic reactor manufactured in HDPE High Density Polyethylene produced by the rotomolding process in substitution to the conventional reactors built in stonemasonry, working in a batch regime and buried in the soil. The state of tensions and the deformations were assessed using the program of Finite Elements ABAQUS version 6.5 and the mesh of the knots using the program MSC PATRAN 2005 forming 7329 knots and 2004 elements, in an optimized mesh for the areas of larger curvature (tension concentrator points). The loading is formed with an internal pressure of the biogas of 5kPa added of biomass hydrostatic load of 6000 kg in an elastic foundation calculated by the ratio pressure/settling starting from the Module of equivalent Elasticity of the soil (Esolo). Comparing the state of tensions assessed during the loading was possible to verify that the largest tension obtained in the most critical element goes the most probable utilization of the reactor, reached the value of 7, 46 MPa (it doesn't surpass 40% of the smallest resistance value to the traction and to the shearing strain of HDPE of 20 MPa) and the largest ratio of dR/R deformation was of 1.0%. The most critical assessed case was when the reactor is buried in soil with Esolo = 1,55 MPa and material with EPEAD = 1550 MPa, totally empty and with a superficial overload in the land of 20kN/m2 generating a tension of 17,80 MPa in the element 1955 (reaching 89% of the smallest resistance value to the traction and the shearing strain of a 20 MPa HDPE). The obtained results confirmed that the reactor produced in HDPE substitutes with advantages the models manufactured in stonemasonry, supporting the internal biogas pressure and the biomass load.

Cette thèse présente un système bioélectronique prometteur, l’Hynet. Ce Réseau Hybride (vivant-artificiel) est conçu pour l’étude du comportement à long terme des cellules électrogénératrices, comme les neurones et les cellules betas, en deux aspects : l’individuel et en réseau. Il est basé sur une boucle fermée et sur la communication en temps réel entre la culture cellulaire et une unité artificielle (Matériel, Logiciel). Le premier Hynet utilise des Matrices d’électrodes (MEA) commerciales qui limitent les performances spatiotemporelles du Hynet. Une nouvelle Matrice d’électrodes intelligente (iMEA) est développée. Ce nouveau circuit intégré, analogique et mixte, fournit une interface à forte densité, à forte échelle et adaptative avec la culture. Le nouveau système améliore le traitement des données en temps réel et une acquisition faible bruit du signal extracellulaire. / This thesis presents a promising new bioelectronics system, the Hynet. The Hynet is a Hybrid (living-artificial) Network, developed to study the long-term behavior of electrogenic cells (such as Neurons or Beta-cells), both individually and in a network. It is based on real-time closed-loop communication between a cell culture (bioware) and an artificial processing unit (hardware and software). In the first version of our Hynet, we use commercial Multielectrode Arrays (MEA) that limits its spatiotemporal performances. A new Intelligent Multielectrode Array (iMEA) is therefore developed. This new analog/mixed integrated circuit provides a large-scale, high-density, and adaptive interface with the Bioware, which improves the real-time data processing and the low-noise acquisition of the extracellular signal. / Esta dissertação de doutorado apresenta um sistema bioeletrônico auspicioso, o Hynet. Esta Rede Híbrida (viva e artificial), é concebida para o estudo do comportamento à longo prazo de células eletrogeneradoras (como neurônios ou células beta), em dois aspectos : individual e em redes. Ele é baseado na comunicação bidirecional, em laço fechado e em tempo real entre uma cultura celular (Bioware) e uma unidade artificial (Hardware ou Software). Um primeiro Hynet é apresentado, mas o uso de Matrizes de Eletrodos (MEA) comerciais limita a performance do sistema. Finalmente, uma nova Matriz de Eletrodos Inteligente (iMEA) é desenvolvida. Este novo circuito integrado fornece uma interface adaptativa, em alta densidade e grande escala, com o Bioware. O novo sistema melhora o processamento de dados em tempo real e a aquisição baixo ruído do sinal extracelular.

O presente trabalho foi desenvolvido para avaliar o potencial de utilização de um reator anaeróbico fabricado em PEAD Polietileno de Alta Densidade, produzido pelo processo de rotomoldagem em substituição aos reatores convencionais construídos em concreto e alvenaria, trabalhando em regime de batelada e enterrados no solo. Os estados de tensões e deformações foram avaliados utilizando o programa de Elementos Finitos ABAQUS versão 6.5 e a malha dos nós utilizando o programa MSC PATRAN 2005 formando 7329 nós e 2004 elementos, em uma malha otimizada para as regiões de maior curvatura (pontos concentradores de tensão). O carregamento é formado com uma pressão interna do biogás de 5 kPa acrescido da carga hidrostática de biomassa de 6000 kgf em uma fundação elástica calculada pela razão tensão/recalque a partir do Módulo de Elasticidade equivalente do solo (Esolo). Comparando o estado de tensões avaliado durante o carregamento foi possível constatar que a maior tensão obtida no elemento mais crítico para a utilização mais provável do reator atingiu o valor de 7,46 MPa (não supera 40% do menor valor de resistência à tração e ao cisalhamento do PEAD de 20 MPa) e a maior razão de deformação dR/R foi de 1.0%. O caso mais crítico avaliado foi quando o reator está enterrado, totalmente vazio, em solo com Esolo = 1,55 MPa e o material com EPEAD = 1550 MPa e com uma sobrecarga superficial no terreno de 20kN/m2 gerando uma tensão de 17,80 MPa no elemento 1955 (atingindo 89% do menor valor de resistência à tração e ao cisalhamento do PEAD igual a 20 MPa). Os resultados obtidos comprovam que o reator produzido em PEAD substitui com vantagens os modelos fabricados em concreto ou alvenaria, suportando a pressão interna do biogás e a carga de biomassa. / The present work was developed to evaluate the potential of uses of an anaerobic reactor manufactured in HDPE High Density Polyethylene produced by the rotomolding process in substitution to the conventional reactors built in stonemasonry, working in a batch regime and buried in the soil. The state of tensions and the deformations were assessed using the program of Finite Elements ABAQUS version 6.5 and the mesh of the knots using the program MSC PATRAN 2005 forming 7329 knots and 2004 elements, in an optimized mesh for the areas of larger curvature (tension concentrator points). The loading is formed with an internal pressure of the biogas of 5kPa added of biomass hydrostatic load of 6000 kg in an elastic foundation calculated by the ratio pressure/settling starting from the Module of equivalent Elasticity of the soil (Esolo). Comparing the state of tensions assessed during the loading was possible to verify that the largest tension obtained in the most critical element goes the most probable utilization of the reactor, reached the value of 7, 46 MPa (it doesn't surpass 40% of the smallest resistance value to the traction and to the shearing strain of HDPE of 20 MPa) and the largest ratio of dR/R deformation was of 1.0%. The most critical assessed case was when the reactor is buried in soil with Esolo = 1,55 MPa and material with EPEAD = 1550 MPa, totally empty and with a superficial overload in the land of 20kN/m2 generating a tension of 17,80 MPa in the element 1955 (reaching 89% of the smallest resistance value to the traction and the shearing strain of a 20 MPa HDPE). The obtained results confirmed that the reactor produced in HDPE substitutes with advantages the models manufactured in stonemasonry, supporting the internal biogas pressure and the biomass load.