In this study, two quasi-isotropic carbon fiber-reinforced polyimide material systems, IM7/K3B and IM7/PETI-5, were thermally aged at 163°C for up to 3000 hours under a static compressive load. The future goal of this study is to determine the effect of 10,000 hours (currently underway) and possibly seven years of aging on these materials. The compressive load was applied using steel fixtures supplied by The Boeing Company. Back-to-back gages on the aging panels monitored compressive strain as well as bending strain. Following aging at 1500 and 3000 hours, ambient residual compression properties were assessed using the IITRI compression test method. Unexposed specimens were also tested to obtain baseline properties for comparison. These results showed that 3000 hours of stressed isothermal aging did not significantly affect the compressive properties of the two composite systems. A slight increase in scatter of the residual strength numbers was observed. Statistical evaluation of the results was used to compute design allowables and quantify changes in scatter. Differential scanning calorimetry (DSC) was used to monitor any changes in glass transition temperature as a result of the aging. Only small changes were observed in the DSC scans. Dynamic thermogravimetric analysis (TGA) tests were used to compare weight loss rate versus temperature results for the different age materials. Results show different rates of degradation occurring in the different K3B polymer aging histories. In addition to establishing the effect of isothermal aging under load on the compressive moduli and strength of two polymer-matrix composites, this experiment links increasing scatter in residual strength measurements to changing thermogravimetric results. / Master of Science

Este trabalho apresenta um estudo dos processos de prensagem e sinterização do politetrafluoretileno (PTFE) com o objetivo principal de investigar a influência dos parâmetros desses processos na microestrutura e nas propriedades mecânicas do material após sinterização. O PTFE faz parte do grupo dos termoplásticos, mas assim como outros polímeros de alto peso molecular, apresenta elevada viscosidade no estado fundido que impede sua utilização em moldagem por injeção, e seu processamento é realizado por compactação a frio do pó polimérico seguida de sinterização. No processo de sinterização é aplicado um tratamento térmico acima da temperatura de fusão do material que é responsável por grandes deformações anisotrópicas que, por sua vez, são dependentes do histórico de carregamentos induzidos na fase de compactação. Com o objetivo de desenvolver modelos de comportamento termomecânicos para realizar simulações computacionais dessas etapas de fabricação, ensaios experimentais foram realizados para se investigar os diferentes mecanismos de evolução microestrutural e de deformações nas etapas de compactação e sinterização. O estudo experimental do processo de compactação compreendeu a realização de ensaios de compactação uniaxial (oedométrico), de compactação hidrostática em prensa isostática e ensaios triaxiais verdadeiros em um dispositivo original acoplado numa prensa triaxial com seis atuadores eletrohidráulicos. Através dos resultados obtidos dos ensaios de compactação foi possível identificar os parâmetros do modelo de Drucker-Prager/cap, disponível na biblioteca de leis de comportamento do programa de cálculo pelo método dos elementos finitos ABAQUSTM, que permitiu de simular numericamente alguns casos simples. O estudo experimental do processo de sinterização foi realizado com o auxílio de ensaios de termogravimetria (TGA), calorimetria exploratória diferencial (DSC) e ensaios de dilatometria em corpos-de-prova isótropos e anisótropos com diferentes índices de vazios. Através dos resultados obtidos destes ensaios foi possível identificar que a deformação global de sinterização é composta por uma deformação térmica reversível, uma deformação devido à mudança de fase cristalina em fase amorfa -ou vice-versa-, uma deformação devido ao fechamento dos vazios e uma deformação de recuperação. Este estudo foi realizado em dois tipos de materiais, sendo o PTFE puro e o PTFE reforçado com 5wt% de EkonolTM e 5wt% de fibras de carbono, respectivamente comercializados pelos nomes de TeflonTM 6407 e TeflonTM 6507. / The main objective of this work is to study the influence the process parameters on the microstructure and the mechanical properties of components manufactured by compaction at room temperature and sintering of polytetrafluorethylene (PTFE). Similary to other High Molecular Weight Polymers and although it belongs to the group of thermoplastic polymers, since it cannot be processed in the melt state because its very high viscosity, PTFE, is powder processed -that consists in sintering compacted powder-. Sintering corresponds to a heat treatment up to temperatures higher than the melting temprature, inducing finite deformations that are generally anistropic and dependent on the mechanical loading the material has been submitted to during the pre-compaction at room temperature. In order to develop thermo-mechanical constitutive equations that could be used during predictive numerical simulations of the whole process, different tests have been performed to study the different mechanisms that are responsible for microstructural evolutions and deformations during compaction and sintering. The experimental study of the compaction has been performed via uniaxial (oedometric) compaction tests, hydrostatic compaction tests that were made with an isostatic hydraulic press and triaxial tests that were made with and original device installed on an electrohydraulic testing machine six actuators. A \"Drucker-Prager/cap\" type elasto-plastic model -as available in the constitutiveequations library of ABAQUSTM industrial finite element software- has been identified from the results of these tests, so that a few simple cases have been numerically simulated. The experimental study of the sintering process has been performed via Thermo-Gravimetric Analyses (TGA), Differential Scanning Calorimetric analyses (DSC) and dilatometry tests that were performed on isotropic or anisotropic specimens with different values of the porosity From the results of these tests it has been possible to decompose the sintering deformation into different mechanisms, viz. a reversible thermal expansion, a strain that is linked to the transition from the crystalline phase to the amorphous phase -or vice versa-, a pore closure strain and a recovery strain. This study has been performed on a powder made of pure PTFE and a powder of PTFE filed with 5wt% EkonolTM and 5wt% of carbon fibres, respectively available as TeflonTM 6407 and TeflonTM 6507.

This PhD thesis presents investigations of perovskite-related compounds in systems of interest for applications in components in solid oxide fuel cells. The compound compositions derive from substitutions in the parent compounds LaCoO3, LaCrO3 and SrFeO3. Novel phases La2Co1+z(MgxTi1-x)1-zO6 were synthesized and investigated with regard to structure, thermal expansion, electronic and magnetic properties. The study focused on the composition lines La2Co(MgxTi1-x)O6 (z=0), where the oxidation state of Co nominally changes from +2 (x=0.0) to +3 (x=0.5), and La2Co1+z(Mg0.5Ti0.5)1-zO6, with a varying fraction of Co3+ ions. XANES data show that the Co ions in the system have discrete oxidation states of +2 and +3. The TEC increases with increasing x due to an increasing contribution from spin state transitions of the Co3+ ions. Novel compounds La2Cr(M2/3Nb1/3)O6 with M=Mg, Ni, Cu were synthesized and characterized with respect to structure and magnetic properties. XRPD and NPD data indicate Pbnm symmetry; however, SAED patterns and HREM images indicate a P21/n symmetry for M=Mg, and Cu. The magnetic measurements results were rationalized using the Goodenough-Kanamori rules. Oxygen-deficient phases with x≥0.63 in SrxY1-xFeO3-δ and Sr0.75Y0.25Fe1-yMyO3-δ (M=Cr, Mn, Ni and y=0.2, 0.33, 0.5), were synthesized and characterized with respect to structure, oxygen content, thermogravimetry, TEC, conductivity and magnetic properties. Powder patterns of phases agree with cubic  perovskite structures. NPD data for x=0.75 reveal anisotropic displacement for the O atom, related to local effects from Fe3+/Fe4+ ions. SAED patterns for x=0.75 reveal the presence of an incommensurate modulation. The compounds start to lose oxygen in air at ~ 400°C. The TEC up to ~400°C for x=0.75 is ~10.5 ppm/K and increase to ~17.5 ppm/K at higher temperatures. The conductivity for x=0.91 is 164 S/cm at 400°C. Partial substitution of Fe by Cr, Mn or Ni does not increase the conductivity or decrease TEC.

Die Salicylsäure (SA) ist ein wichtiges Signalmolekül bei der Regulation der pflanzlichen Pathogenabwehr. as-1-ähnliche cis-Elemente in den Promotoren von vielen Abwehrgenen vermitteln SA- und auch Auxin-induzierbare Genexpression. Diese Elemente werden vom ASF-1/SARP-Proteinkomplex erkannt, dessen Hauptkomponenten DNA-Bindeproteine aus der TGA-Familie der pflanzlichen bZIP-Transkriptionsfaktoren sind. In dieser Arbeit wurden Fusionsproteine von TGA2.1, TGA2.2 und TGA1a mit GFP unter der Kontrolle des HBT-Promotors transient in Pflanzenprotoplasten oder stabil in transgenen Pflanzen exprimiert und direkt in lebenden Zellen über Fluoreszenz- und konfokale Laser-Scanning-Mikroskopie visualisiert. Bei den mikroskopischen Analysen konnte die Fluoreszenz der drei TGA-GFP-Fusionsproteine überwiegend im Kern (mit Ausnahme des Nukleolus) beobachtet werden. Allerdings ließen sich biochemisch mit Hilfe eines Antiserums gegen die beiden C Termini der TGA-Faktoren auch geringe Mengen von TGA2.1-GFP und TGA2.2-GFP in cytosolischen Extrakten der entsprechenden transgenen Pflanzen nachweisen. Fusionen der C terminalen Anteile von TGA2.2 und TGA1a an den C Terminus von CHS-GFP wurden bei transienter Expression ebenfalls im Cytosol beobachtet. Es konnte nicht abschließend geklärt werden, ob dass auf das Fehlen der NLS oder auf die Anwesenheit einer NES zurück zu führen ist. Die TGA-GFP-Fusionsproteine konnten das as 1-Element in vitro in Gelretardationsanalysen erkennen und in Form von Homo-oder Heterodimeren daran binden. Die TGA-GFP-Fusionsproteine waren auch in der Lage, die Expression des frühen (immediate-early) GST-Gens Nt103 in Blättern nach Induktion mit Salicylsäure oder Auxin zu beeinflussen. TGA2.1-GFP und TGA2.2-GFP zeigten im allgemeinen einen positiven Effekt auf die Nt103-mRNA-Menge (2-4-facher Anstieg verglichen mit dem Wildtyp), wobei sich der Effekt stärker auf die SA-induzierte Expression auswirkte als auf die 2,4-D-Proben. TGA1a-GFP schien die Expression von Nt103 in Blättern in beiden Fällen leicht negativ oder gar nicht zu beeinflussen. Die Mobilitätsparameter der verschiedenen TGA-GFP-Fusionsproteine im Kern wurden mit Hilfe von FCS, kombiniert mit CLMS, untersucht. Während die Mobilität des Kontrollproteins TetR-GFP, dass keine endogenen Interaktionpartner hat, einheitlich war, schienen Subfraktionen der TGA-GFP Fusionproteine in ihrer Mobilität beeinflusst. Generell konnte zwischen einer mobileren und einer weniger mobilen Fraktion unterschieden werden. Bei manchen Messungen waren die TGA-Faktoren im Kern sogar gänzlich immobil. Die relative Anteil von weniger mobilen, bzw. immobilen und mobilen TGA-faktoren unterschied sich in den unterschiedlichen analysierten Zelltypen (längliche und echte Epidermiszellen, Schießzellen, Trichomzellen). Um einen eindeutigen Effekt von Salizylsäure auf die Mobilität der TGA-Faktoren festzumachen, sind wegen der großen Variabilität weitere Messungen nötig.

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Este trabalho apresenta um estudo dos processos de prensagem e sinterização do politetrafluoretileno (PTFE) com o objetivo principal de investigar a influência dos parâmetros desses processos na microestrutura e nas propriedades mecânicas do material após sinterização. O PTFE faz parte do grupo dos termoplásticos, mas assim como outros polímeros de alto peso molecular, apresenta elevada viscosidade no estado fundido que impede sua utilização em moldagem por injeção, e seu processamento é realizado por compactação a frio do pó polimérico seguida de sinterização. No processo de sinterização é aplicado um tratamento térmico acima da temperatura de fusão do material que é responsável por grandes deformações anisotrópicas que, por sua vez, são dependentes do histórico de carregamentos induzidos na fase de compactação. Com o objetivo de desenvolver modelos de comportamento termomecânicos para realizar simulações computacionais dessas etapas de fabricação, ensaios experimentais foram realizados para se investigar os diferentes mecanismos de evolução microestrutural e de deformações nas etapas de compactação e sinterização. O estudo experimental do processo de compactação compreendeu a realização de ensaios de compactação uniaxial (oedométrico), de compactação hidrostática em prensa isostática e ensaios triaxiais verdadeiros em um dispositivo original acoplado numa prensa triaxial com seis atuadores eletrohidráulicos. Através dos resultados obtidos dos ensaios de compactação foi possível identificar os parâmetros do modelo de Drucker-Prager/cap, disponível na biblioteca de leis de comportamento do programa de cálculo pelo método dos elementos finitos ABAQUSTM, que permitiu de simular numericamente alguns casos simples. O estudo experimental do processo de sinterização foi realizado com o auxílio de ensaios de termogravimetria (TGA), calorimetria exploratória diferencial (DSC) e ensaios de dilatometria em corpos-de-prova isótropos e anisótropos com diferentes índices de vazios. Através dos resultados obtidos destes ensaios foi possível identificar que a deformação global de sinterização é composta por uma deformação térmica reversível, uma deformação devido à mudança de fase cristalina em fase amorfa -ou vice-versa-, uma deformação devido ao fechamento dos vazios e uma deformação de recuperação. Este estudo foi realizado em dois tipos de materiais, sendo o PTFE puro e o PTFE reforçado com 5wt% de EkonolTM e 5wt% de fibras de carbono, respectivamente comercializados pelos nomes de TeflonTM 6407 e TeflonTM 6507. / The main objective of this work is to study the influence the process parameters on the microstructure and the mechanical properties of components manufactured by compaction at room temperature and sintering of polytetrafluorethylene (PTFE). Similary to other High Molecular Weight Polymers and although it belongs to the group of thermoplastic polymers, since it cannot be processed in the melt state because its very high viscosity, PTFE, is powder processed -that consists in sintering compacted powder-. Sintering corresponds to a heat treatment up to temperatures higher than the melting temprature, inducing finite deformations that are generally anistropic and dependent on the mechanical loading the material has been submitted to during the pre-compaction at room temperature. In order to develop thermo-mechanical constitutive equations that could be used during predictive numerical simulations of the whole process, different tests have been performed to study the different mechanisms that are responsible for microstructural evolutions and deformations during compaction and sintering. The experimental study of the compaction has been performed via uniaxial (oedometric) compaction tests, hydrostatic compaction tests that were made with an isostatic hydraulic press and triaxial tests that were made with and original device installed on an electrohydraulic testing machine six actuators. A \"Drucker-Prager/cap\" type elasto-plastic model -as available in the constitutiveequations library of ABAQUSTM industrial finite element software- has been identified from the results of these tests, so that a few simple cases have been numerically simulated. The experimental study of the sintering process has been performed via Thermo-Gravimetric Analyses (TGA), Differential Scanning Calorimetric analyses (DSC) and dilatometry tests that were performed on isotropic or anisotropic specimens with different values of the porosity From the results of these tests it has been possible to decompose the sintering deformation into different mechanisms, viz. a reversible thermal expansion, a strain that is linked to the transition from the crystalline phase to the amorphous phase -or vice versa-, a pore closure strain and a recovery strain. This study has been performed on a powder made of pure PTFE and a powder of PTFE filed with 5wt% EkonolTM and 5wt% of carbon fibres, respectively available as TeflonTM 6407 and TeflonTM 6507.

Cette étude s’inscrit dans le cadre du projet MINERVE de la région wallonne quivise notamment à valoriser les anciens centres d’enfouissement technique et leur contenuau travers de la production de matières premières et de sources d’énergie. Plus particulièrement,l’objectif de ce travail est d’étudier un procédé de co-pyrolyse de déchetsplastiques et d’huiles de lubrification usagées, ayant pour finalité la production d’uncombustible alternatif liquide pour l’industrie, en vue d’une future montée en échelledu procédé.Pour ce faire, différentes approches ont été poursuivies. Premièrement, nous avonsmis en place un réacteur de 5 litres, agité et scellé hermétiquement, permettant demener des essais de co-pyrolyse. Des essais de co-pyrolyse d’un mélange de déchetsplastiques excavés et d’huiles de lubrification usagées ont été menés dans le réacteur.L’influence des paramètres clés du procédé, tels que la température maximale, la fractionmassique de plastiques dans le mélange ainsi que la vitesse de refroidissement, surle procédé et la qualité du produit fini a été étudiée. Nous avons été en mesure deproduire un combustible alternatif liquide, possédant un pouvoir calorifique d’environ30 MJ/kg, par la co-pyrolyse d’un mélange contenant 60% de plastiques, en chauffantle mélange durant 13 h, en atteignant une température maximale de 387°C et enlaissant la pression au sein du réacteur monter jusqu’environ 30 bars. Les besoins énergétiquesdu procédé ont été évalués à environ 8 MJ/kg de déchets à pyrolyser, grâce àun modèle de transferts thermiques développé pour le système constitué du réacteur deco-pyrolyse. Ensuite, une méthode a été développée pour déterminer le temps de fonted’une particule de plastique en fonction de sa plus petite dimension. L’application decette méthode nous a permis de déterminer que la plus petite dimension maximale quepeuvent avoir les particules de plastiques dans le mélange plastique/huile, pour queleur fusion ne limite pas le procédé de co-pyrolyse, est d’environ 3 cm. Deux analysesthermiques, la thermogravimétrie isotherme et la calorimétrie différentielle à balayage,ont été combinées pour caractériser le craquage thermique et son influence sur plusieurspolymères. L’influence du craquage thermique sur les polymères a été évaluée sur basede l’analyse de la fusion ou de la transition vitreuse du polymère. Les protocole et dispositifexpérimentaux de co-pyrolyse de déchets plastiques et d’huiles de lubrificationusagées à l’échelle du laboratoire ont été adaptés pour pouvoir co-pyrolyser un mélangecontenant du PVC. Différents essais de co-pyrolyse par étapes ont été menés pour évaluerl’influence des paramètres comme l’évolution de la température pendant l’essai, lecontenu en PVC du mélange et le plastique en mélange avec le PVC (LDPE ou PS).Enfin, les interactions qui prennent place entre le LDPE ou le PS et une huile, lorsde leur co-pyrolyse, ont été mises en évidence à l’aide d’essais de thermogravimétriehaute résolution. Nous avons tenté d’expliquer les interactions mises en évidence, grâceà une combinaison d’analyses thermiques permettant de caractériser, voire d’identifier,les produits de décomposition de l’échantillon, en continu ou en fin de chauffe.This study takes part in the MINERVE (Walloon region) which aims at enhancingthe old landfills and valorize their content through the production of raw materials andenergy sources. Specifically, the objective of this work is to study a co-pyrolysis processof waste plastics and used lubrication oils, whose purpose is the production of a liquidalternative fuel for industry, in order to future scaling up the process.To do so, different approaches have been pursued. First, we set up a 5 liter reactor,stirred and hermetically sealed for performing co-pyrolysis tests. Co-pyrolysis tests ofa mixture of excavated plastic wastes and used lubrication oils were performed in thereactor. The influence of key parameters, such as maximum temperature, the massfraction of plastics in the mixture and the cooling rate, on the process and the qualityof the fuel was investigated. We were able to produce a liquid alternative fuel, witha calorific value of about 30 MJ/kg by co-pyrolyzing a mixture containing 60 % ofplastic, heating the mixture for 13 h, reaching a maximum temperature of 387°C anda maximum pressure of about 30 bar. The energy requirements of the process wereevaluated at about 8 MJ per kg of waste through a heat transfer model developed forthe system consisting of the co-pyrolysis reactor. In addition, a method was developedto determine the time of melting of a plastic particle according to its smallest size.The application of this method allowed us to determine that the maximum smallestsize that can have plastic particles in plastic/oil mixture, so that their melting willnot limit the co-pyrolysis process, is about 3 cm. Two thermal analysis techniques,isothermal thermogravimetry and differential scanning calorimetry, were combined tocharacterize the thermal cracking and its influence on several polymers. The influence ofthermal cracking of the polymers was evaluated based on the analysis of the melting orglass transition of the polymer. The experimental protocol and device of waste plasticsand used lubricating oils co-pyrolysis have been adapted to co-pyrolyze a mixturecontaining PVC. Two-step co-pyrolysis tests were performed to evaluate the influenceof parameters such as the evolution of the temperature during the test, the PVCcontent of the mixture and the plastic that is mixed with PVC (LDPE or PS). Finally,interactions that take place between the LDPE or the PS and an oil, when co-pyrolyzed,have been identified with high resolution thermogravimetry experiments. We tried toexplain the identified interactions through a combination of thermal analyzes thatcharacterized or identified the sample decomposition products, continuously duringthe thermal decomposition or at its end. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

To release energy from chemically stored energy in the biomass was the new investigation in recent years. Utilizing of biomass for this purpose occur in two different ways, directly by burning (combustion) the biomass and indirectly by pyrolysis process which will convert the biomass to three main products, bio- tar, bio- char and synthetic gas. Biomass contains different amount of inorganic compound, especially alkali metals which causes some diverse impacts on combustion, pyrolysis and gasification process such as corrosion, agglomeration and fouling problems. This project aims to investigate the effect of K2CO3 on the pyrolysis and gasification processes of three different types of fuel; wood pellets, forest residue pellets and synthetic waste pellets at three different temperatures, 750 °C, 850 °C and 900 °C respectively. The purpose of this work to study and clarify the influence of K2CO3 on char yield, tar yield and tar compositions and the gasification rate and the reactivity of different fuels char. The pyrolysis process was carried out in a fluidized bed reactor during 2 minutes and the products were tar, char and synthetic gas. In this project interested in char and tar only. Char yield calculated and the results shows the char yield increase with increasing of [K2CO3]. While the tar analysis carried on GC- MS instrument at HB to study the tar yield and compositions. The results showed that potassium carbonate has not so much effect on tar yield and its composition. The last part was gasified the char in TGA with steam and CO2 as oxidizing media to study the influence of [K2CO3] on gasification rate and the reactivity of char samples at different temperatures. The result showed the [K2CO3] has inhibitory effect on gasification rate and the reactivity.