Ce manuscrit de thèse présente la synthèse et l’optimisation d’un nouveau matériau d’électrode adapté aux biopiles enzymatiques et hybrides qui sont des systèmes capables de convertir de l’énergie chimique en énergie électrique en utilisant des catalyseurs enzymatiques. Ce matériau est constitué de nanofibres de carbone fabriquées par la technique d’electrospinning à partir d’une solution de polyacrylonitrile, suivi de traitements thermiques appropriés. Les propriétés structurales et électriques des nanofibres de carbone les rendent très intéressantes en tant que matériaux d’électrode tridimensionnels pour développer des systèmes de conversion d’énergie. Dans ce travail, afin d’améliorer ces propriétés, les nanofibres de carbone ont été synthétisées en les modifiant soit avec des nanotubes de carbone, soit in situ avec des particules d’or. D’autre part, l’influence de l’organisation spatiale des fibres a été étudiée avec la synthèse de fibres alignées et non alignées. La morphologie et la structure des fibres ont été caractérisées puis ces fibres ont été utilisées en tant que matériaux d’électrode modifiés par des enzymes oxydoréductases pour la réduction électrocatalytique de l’oxygène à la cathode. Des enzymes ont été encapsulées dans des matrices de Nafion, polypyrrole ou chitosan pour réaliser soit du transfert médiaté, soit du transfert direct. Pour la première fois, ces matériaux d’électrode ont été utilisés pour construire des biopiles enzymatiques et hybrides utilisant comme combustible soit de l’éthanol ou du glucose. Les résultats obtenus dans ce travail ont démontré les perspectives prometteuses des matériaux 3D à surface spécifique élevée pour améliorer les performances électriques des biopiles par rapport à des matériaux denses. / This thesis manuscript presents the synthesis and optimization of a new electrode material suitable for enzymatic and hybrid biofuel cells, which are systems capable of converting chemical energy into electrical energy by using enzymatic catalysts. This material is composed of carbon nanofibers fabricated by the electrospinning of a polyacrylonitrile solution, followed by appropriate thermal treatments. Carbon nanofibers structural and electrical properties make them very suitable for application as tridimensional electrode materials for the development of energy conversion systems. In this work, aiming to improve these properties, carbon nanofibers were synthesized and modified either with carbon nanotubes, or in situ with gold particles. In a different strategy, the influence of the fibers spatial organization was studied through the synthesis of aligned and randomly organized fibers. Fibers structure and morphology were characterized, and then the fibers were employed as electrode materials modified with oxidoreductase enzymes for the reduction of oxygen at the cathode compartment. Enzymes were entrapped in matrixes composed of Nafion, polypyrrole or chitosan in order to realize either mediated or direct electron transfer. For the first time, these electrode materials were employed for the construction of enzymatic or hybrid biofuel cells, with ethanol or glucose as fuels. The results obtained in this work were able to demonstrate the promising perspectives of 3D materials with high specific surface to enhance the performance of biofuel cells, if compared to dense materials.

Att en byggnadsdel kan vara i behov av en förstärkning är inte ovanligt i dagsläget. Det kan handla om ett bjälklag som kommer utsättas för mer last då verksamheten ändras från bostad till kontorslandskap. Alternativa lösningar till att förstärka en sådan konstruktion skulle antingen vara att införa stålbalkar och pelare eller gjuta på det befintliga bjälklaget. Det som få konstruktörer och entreprenörer tänker på är att en kolfiberlösning kan vara ett smidigare alternativ. Examensarbetes syfte är att undersöka om kolfiberförstärkningar kan konkurrera med traditionella förstärkningsmetoder. Lyfta fram för-och nackdelar för samtliga förstärkningsmetoder och väga dem mot varandra utifrån en beräkningssynpunkt och utförandemässigt. Metoder för att få en bra förståelse för hur kolfiber höjer böjmomentkapaciteten är laboration med provtryckningar samt beräkningar på ett verkligt broprojekt. I båda fallen har kolfiberlösningen jämförts med traditionella lösningar. Arbetets resultat visar att kolfiberförstärkningar kan, i många fall, ersätta traditionella förstärkningsmetoder. Detta på grund av sin lätta vikt och höga draghållfasthet som gör det möjligt att på ett effektivt sätt höja böjmomentkapaciten hos byggnadsdelar. Enligt laborationen gav kolfiberförstärkningen ungefär samma procentuella ökning i hållfasthet som en plattstålförstärkning. / A building part could need a reinforcement. It could be a system of joists that are soon going to be loaded with heavier loads when business is changing from residence to an office. The alternate solution to reinforce that kind of construction would be with steel beams and columns or increase the height of the floor with more concrete. What few constructors and contractors know are the solution with carbon fiber reinforcement could be a better alternative. The purpose of the thesis is to study if carbon fiber reinforcement could compete with traditional reinforcement methods. From a calculating and a work-related perspective the project will underline the pro and cons with all of the reinforcement methods. To demonstrate how carbon fiber increase the bending moment capacity have lab and calculation of a real bridge project been executed. In both cases have a carbon fiber solution been compared with traditional reinforcement methods. The result of the thesis shows that carbon fiber reinforcement could replace traditional methods in many cases. The pros with the carbon fiber reinforcement is the light weight and high tensile strength that makes it possible, on an efficient way, increase the bending moment capacity in a building part. The thesis lab result shows that a carbon fiber reinforcement does have the same percentage increase in strength as a flat steel reinforcement.

[pt] Este trabalho experimental tem como objetivo estudar a ductilidade de vigas retangulares de concreto armado reforçadas à flexão utilizando compósitos com tecido de fibras de carbono. No estudo realizado são apresentados os conceitos clássicos de ductilidade e é proposta uma nova sistemática para obtenção do índice de ductilidade, baseada nas considerações da energia elástica e da energia inelástica. A ductilidade é determinada por meio de um índice energético, que se caracteriza como uma forma mais eficiente para a determinação e análise da ductilidade em elementos estruturais. O programa experimental consistiu no ensaio de sete vigas bi-apoiadas, sendo uma viga de referência e as demais reforçadas à flexão com tecido de fibras de carbono. Todas as vigas possuem as mesmas características mecânicas e geométricas e foram dimensionadas de modo a garantir a ruptura por flexão. A viga de referência, a primeira ensaiada, não foi reforçada e serviu para comparações de incremento de rigidez e resistência após a aplicação do reforço. As vigas reforçadas foram divididas em dois grupos. O grupo A é constituído de duas vigas, reforçadas inicialmente com uma e duas camadas de tecido de fibra de carbono. O grupo B é constituído por quatro vigas que foram reforçadas após um carregamento inicial. Neste grupo, duas vigas foram reforçadas com uma camada de tecido de fibra de carbono e as outras duas foram reforçadas com duas camadas de tecido de fibras de carbono, correspondendo à mesma área total de reforço das anteriores. Todas as vigas foram concretadas, instrumentadas e ensaiadas no Laboratório de Estruturas e Materiais da PUC-Rio. Os ensaios das vigas do grupo B foram realizados com as vigas pré-ensaiadas, reforçadas sob deformação constante e em seguida levadas à ruptura. A deformação foi mantida constante durante a aplicação e o período de cura do reforço. Os resultados obtidos em termos de carga, flecha, momento, curvatura, ductilidade energética e rotação plástica foram analisados. Os estudos realizados mostraram que o reforço com compósitos de fibras de carbono é uma técnica eficaz, que as vigas apresentam ductilidade adequada e que os índices energéticos propostos são adequados para este tipo de estudo. / [en] The objective of this experimental work is to study the ductility of reinforced concrete beams strengthened in flexure using externally bonded carbon fiber fabric composites. This study presents the classic concepts of ductility and proposes a new systematic to obtain the ductility index, which is based on the considerations of elastic and inelastic energy. The ductility was determined by an energetic index, which has seen to be a more efficient method to establish and analyze the ductility of structural elements. The experimental program consisted of seven beams tests. One was used as a control beam without external reinforcement and the others were strengthened with carbon fibers in order to resist flexural load. All the beams had the same mechanical and geometrical characteristics and were designed to fail in flexure. The control beam was not strengthened and its purpose was to compare the stiffness increase and resistance after the strength. The strengthened beams were divided in two groups. Group A was constituted by two beams, initially strengthened by one and two layers of carbon fiber fabric. Group B was formed by four beams which were strengthened after the application of an initial load. In this group, two beams were strengthened by one layer of carbon fiber fabric and the other two were strengthened by two layers, which corresponded to the same area of the others. All the beams were cast, instrumented and tested in the Structural and Materials Laboratory at PUC-Rio. Group B tests were performed with the pretested beams strengthened under constant strain, and then loaded up to rupture. The strain was kept constant during the application and cure of the external reinforcement. The results obtained in terms of load, deflection, resistant moment, curvature, energetic ductility indexes and plastic rotation were analyzed. The study showed that the reinforcement using carbon fiber fabric composites is an efficient technique, the beams presented adequate ductility and the proposed energetic ductility indexes are consistent formulae for this kind of study.

The main aim of this work id to provide integral methods to predict and characterize the properties of composite structures based on hybrid polymers and reinforcements, that could lead to useful results from an industrial point of view. This is addressed, if possible, by theoretical predictions of the effective properties by using the available experimental data. The first part is focused on the scientific achievements of the author that allowed a quantitative characterization of the main effective properties of several composite architectures from hybrid polymers and reinforcements, based on bio matrices, tailor-made matrices and different theoretical and simulation methods using computer software to allow good comparison. The second part defines the future research lines to continue this initial investigation. The main objectives are clearly defined to give the reader a sound background with the appropriate concepts that are specifically discussed in the following chapters. As a main objective, this research work makes a first attempt to provide a systematic analysis and prediction of composite hybrid structures. / El objetivo general del trabajo es proporcionar medios integrales para predecir y caracterizar las propiedades de las estructuras de compuestos basados en polímeros y refuerzos híbridos, principales que pueden producir resultados de utilidad práctica simultáneamente. Esto se logra comparando, siempre que sea posible, las predicciones teóricas de las propiedades efectivas con los datos experimentales disponibles. Una primera parte se ocupa de los logros científicos del autor que permitieron caracterizar cuantitativamente las principales propiedades efectivas de las arquitecturas de compuestos basados en polímeros y refuerzos híbridos, basados en matrices bio, auto-desarrollados y diferentes métodos teóricos y de simulación por ordenador utilizados para la comparación. La segunda parte identifica las orientaciones futuras para la evolución y desarrollo de la ciencia y la investigación. Los objetivos generales fueron subrayados y concisos para dar al lector una visión previa de los conceptos que serán discutidos específicamente en los siguientes capítulos. Indirectamente, apuntan hacia uno de los objetivos principales de este trabajo, a saber, proporcionar una dirección para el análisis sistemático de materiales compuestos a base de refuerzos híbridos. / L'objectiu general d'aquest treball es proporcionar els mitjos integrals per tal de predir i caracteritzar les propietats d'estructures de compòsits basats en polímers i reforçaments híbrids, que poden produir resultats amb utilitat pràctica simultàniament. Aquest objectiu s'aconsegueix comparant, sempre que és possible, les prediccions teòriques de les propietats efectives amb les dades experimentals disponibles. Una primera part es centra en els temes científics en què ha treballat l'autor que han permès caracteritzar quantitativament les principals propietats efectives de les arquitectures de compòsits basades en polímers i reforçaments híbrids, derivats de matrius bio, auto-desenvolupats i diferents mètodes teòrics i de simulació informàtica per a una correcta comparació. La segona part identifica les orientacions futures per tal d'establir l'evolució i desenvolupament de la ciència i investigació lligada a la temàtica de la tesi. Els objectius generals han sigut clarament definits per tal de donar-li al lector una visió prèvia i sòlida dels conceptes que es discuteixen en capítols venidors. Indirectament, apunten cap a un dels objectius principals d'aquest treball, a saber, proporcionar una direcció per a l'anàlisi sistemàtica de materials compòsits a base de polímers i reforçaments híbrids. / Motoc, D. (2017). Development of green composites based on epoxidized vegetable oils (EVOs) with hybrid reinforcements: natural and inorganic fibers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90399 / TESIS

[pt] Este trabalho de natureza experimental tem como objetivo estudar o comportamento de vigas de concreto submetidas à torção e reforçadas externamente com compósitos de fibras de carbono (CFC). Treze vigas de concreto com 2,0 m de comprimento e seção transversal de 30 cm х 60 cm foram testadas no Laboratório de Estruturas e Materiais do Departamento de Engenharia Civil (LEM/DEC) da Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio). As vigas foram divididas em quatro séries, sendo uma de referência, composta por quatro vigas sem reforço externo, e outras três séries constituídas por três vigas que foram reforçadas externamente com taxas crescentes de estribos de CFC. Com o propósito de estudar a contribuição do concreto e do reforço de CFC na resistência à torção de vigas, a armadura interna só foi colocada na região de aplicação de cargas e nos apoios para evitar a ruptura local e possibilitar o estudo da região central sem a parcela resistente devida à armadura interna de aço. Os resultados dos ensaios mostraram que as vigas reforçadas apresentaram aumento de carga de fissuração entre 16 por cento e 56 por cento e um acréscimo de resistência à ruptura entre 19 por cento e 47 por cento quando comparadas às vigas de referência. A rigidez das vigas na ruptura aumentou proporcionalmente ao crescimento da taxa de reforço como observado em outros ensaios encontrados na literatura. / [en] This research is an experimental study of torsion strengthening of concrete beams with carbon fibers composites. Thirteen concrete beams with 2.0 long and 30 x 60 cm cross section were tested in the Structures and Materials Laboratory of the Civil Engineering Department (LEM/DEC) of Pontifical Catholic University of Rio de Janeiro (PUC-Rio). The beams were divided in four series, the first one was called the reference series and consisted of four beams without external strengthening and each of the other three series was composed of three beams strengthened with increasing rates of external carbon fibers composites stirrups. In oder to allow the study of the central region without the contribution of the steel reinforcement, the internal steel reinforcement was placed only at points of loads application and supports to prevent the local rupture. The tests results showed that the strengthened beams had an increase of the cracking load between 16 per cent and 56 per cent, and an increase of the rupture load between 19 per cent and 47 per cent when compared to the reference beams. The ultimate resistance of the beams increased proportionally to the rate of external carbon fibers composites strengthening, as was observed by other researchers.

Current insulation solutions across multiple industries, especially the commercial sector, can be bulky and ineffective when considering their volume. Aerogels are excellent insulators, exhibiting low thermal conductivities and low densities with a porosity of around 95%. Such characteristics make aerogels effective in decreasing conductive heat transfer within a solid. These requirements are crucial for aerospace and spaceflight applications, where sensitive components exist among extreme temperature environments. When implemented into insulation applications, aerogel can perform better than existing technology while using less material, which limits the amount of volume allocated for insulation. The application of these materials into composites can result in enhancing a material's thermal and mechanical properties when exposed to mechanical testing. The main objective of this study was to perform theoretical and experimental analysis on a corrugated composite sandwich structure integrated with aerogel insulation by studying its effective thermal conductivity. The aerogel material used was Pyrogel XT-E, a silica aerogel-based fiberglass insulation manufactured by Aspen Aerogels. Theoretical models of the corrugated composite sandwich structure were constructed in ANSYS Workbench based on geometry from a previous study. The main goal of the theoretical models was to analytically and computationally study the effective thermal conductivity of this sample; the conditions of these simulations were modeled after the experimental setup. Additionally, two insulation studies were performed using the thermal models. The first study was performed on a flat plate structure to determine the optimal thickness of Pyrogel XT-E in a flat plate orientation. The second study compared multiple types of common insulation materials to Pyrogel XT-E when integrated into the corrugated composite sandwich structure model. As expected, aerogel particles and Pyrogel XT-E outperformed all insulation materials and had the lowest effective thermal conductivity. Experimental data was obtained using a test enclosure and a heating element source with an integrated temperature control circuit that was designed and built for this study. This experimental data was compared to the theoretical data obtained from the thermal model simulations. The corrugated composite sandwich structure did not perform as well as expected due to thermal bridging along the composite corrugation. Its effective thermal conductivity was much higher than that of the flat plate structure, even though the effective Pyrogel XT-E layer in the corrugated composite sandwich structure was more than twice as thick as the layer in the flat plate structure. Despite thermal bridging, the corrugated composite sandwich structure exhibits superb thermal resistance, which adds to its impressive strength. Thermal conductivity results from this study can be used to design efficient materials for high structural and thermal stress applications.

The presented thesis deals with FDM 3D printing method with emphasis on printing carbon fiber reinforced plastic (CFRP). The aim of this thesis is to engineer the FDM 3D printer designed for printing CFRP and to execute the experiment targeted on comparison of CFRP material properties against commonly used 3D printing plastics such as PLA, ABS, PET etc. The device designed in this work has printing area of 200 x 200 mm with maximum height of the object of 200 mm. The printing bed is heated and the whole device is enclosed. There are two kinds of experiments carried out within the thesis. The first one is focused on tensile strength and Young's modulus of selected materials, while the second experiment compares Charpy's impact strength of specimen with different infill percentage on two selected materials, PET and PET filled with chopped carbon fiber.

The fuel system is a very important part of the vehicle and the engine. The main function is to deliver the fuel- air mixture into the engine cylinder. This thesis describes the design of the Formula student car fuel system. The first part is an introduction to Formula Student competitions. The next section describes the options of the fuel systems structure and options for individual components. Those rules limit the possibilities for us FSAE that in the next chapter. The following parts are major chapters dealing with the actual design of the fuel system and analysis of selected components. The last part are chapters that deal with the production possibilities of parts and subsequent incorporation into the fuel system of the car.

Im Rahmen dieser Arbeit ist eine neuartige, innovative und vielseitig einsetzbare Mikrowellenplasmaquelle entstanden. Die wesentlichen Leistungsmerkmale dieser Plasmaquelle sind deren beliebige Längenskalierbarkeit, sowie der weite Arbeitsdruckbereich vom Feinvakuum bis Atmosphärendruck. Auf der Basis von Voruntersuchungen, sowie umfangreichen Simulationsrechnungen zur Ausbreitung der Mikrowellenfelder, wurde eine Kavität mit einem Querschnitt von 100 mm Breite und 120 mm Höhe entwickelt, welche um ein Vielfaches der Hohlleiterwellenlänge R = 122 mm skalieren lässt. In dieser Arbeit wurde ein Demonstrator mit einer Länge von 720 mm aufgebaut. Die Eigenmodeanalyse ergab, dass die geforderte Feldverteilung bis zu einer Frequenz von 2,48368 GHz erhalten bleibt. Die Einkopplung der Mikrowellenleistung erfolgt über mehrere Hohlleiter, welche gegenüber und nebeneinander an der Kavität angeordnet sind. Umfangreiche Untersuchungen hinsichtlich der verlustfreien Leistungseinkopplung haben ergeben, dass eine phasensynchrone Mikrowelleneinkopplung zwingend erforderlich ist, da sich ansonsten der Wirkungsgrad der Plasmaquelle stark reduziert. Um dem Anspruch der phasensynchronen Einkopplung sowie der notwendigen verlustfreien Mikrowellen–Leistungsverteilung gerecht zu werden, wurden 2–fach und 4–fach Mikrowellenleistungsverteiler entwickelt. Weiterhin wurde erstmalig das Konzept des „injected–Phase–locking“ zur Ansteuerung der Plasmakavität, mittels mehreren gepulsten Mikrowellengeneratoren, erfolgreich evaluiert. Zudem konnte das synchronisierte Pulsen bis zu 20 kHz Pulsfrequenz mit einem minimalen Tastverhältnis von 60 % nachgewiesen werden. Die Stabilisierung von PAN–Fasern mittels Plasma wurde erprobt. Untersuchungen mittels Raman, Dichtemessung sowie Durchmesser wurden durchgeführt. Die Karbonisierung von stabilisierten PAN–Fasern (PANOX, SGL) wurde erfolgreich nachgewiesen. In einem Plasmagasgemisch aus Ar = 0,5 slm und N2 = 0,03 slm, einer Fasergeschwindigkeit von 80 mm/min, einem Prozessdruck 120 – 170 mbar, sowie 2x 3 kW synchronisierter Mikrowellenleistung konnten Fasertemperaturen von bis zu 1100 °C und somit maximale Zugfestigkeiten von 4200 MPa erreicht werden.:1. Einleitung und Motivation 2. Stand der Technik 2.1. Plasmaquellen 2.1.1. RF – Plasma 2.1.2. Corona – Plasma 2.1.3. DBD – Plasma 2.1.4. Mikrowellen – Plasma 2.1.5. Zusammenfassung 2.1.6. Grundlagen Mikrowellenplasma 2.2. Simulationsprogramme 2.3. Konvertierungsverfahren für Kohlenstofffasern 2.3.1. Stabilisierung 2.3.2. Karbonisierung 3. Aufgabenstellung und Zielsetzung 4. Entwicklung der Plasmaquelle 4.1. Konzept der Plasmaquelle 4.2. Resonator 4.2.1. Grundlagen Resonatoren 4.2.2. Analytische Auslegung 4.2.3. Simulation des Resonators 4.3. Mikrowelleneinkopplung 4.3.1. Grundlagen Mikrowellenleitung 4.3.2. Simulation der Einkopplung 4.3.3. Simulation der Plasmakammer 4.4. Mikrowellenleistungsverteilung 4.4.1. Leistungssplitter 4.4.2. synchronisierter und pulsfähiger Mikrowellengeneratorverbund 5. Aufbau einer Demonstrator Plasmaquelle 5.1. Evaluierung der Plasmaquelle 5.1.1. Experimentelle Ermittlung der Parameter für den Betrieb der Plasmaquelle 5.1.2. Optische Emissions–Spektroskopie 5.1.3. Untersuchung der Plasmahomogenität 5.2. Anwendungsbeispiel Faserbehandlung 5.2.1. Aufbau des Faserhandlings 5.2.2. Fasercharakterisierung 5.2.3. Ergebnisse Stabilisierung 5.2.4. Ergebnisse Karbonisierung 6. Zusammenfassung und Ausblick 7. Literaturverzeichnis

Members of the elderly population is disproportionately prone to experiencing mobility impairment due to their aging bodies and as a result have frail bodies that are at a higher risk of grave injury due to falling. In order to combat this assistive mobility devices such as exoskeletons have been developed to help patients enhance their range of motion. With additive manufacturing techniques, such as fused deposition modeling (FDM), becoming a more mainstream form of design, the inclusion of lightweight polymers such as nylon 12 as primary construction materials for these devices has increased. In this thesis computer aided design (CAD) software was used to design a prototype lower body exoskeleton and simulation software was used to give the device the characteristics of Stratasys' nylon 12 carbon fiber FDM material to verify it if could be used as the primary construction material for this device when extruded from a FDM printer on either the XZ or ZX printing plane. From the simulations it was found that the material printed along the XZ plane could create a device that could withstand the weight of an average elderly male patient (200 lbs.) as well as the 35 lbs. of force applied to the device by a linear actuation motor that would be used to extend and contract the exoskeleton leg.