Dissertations / Theses on the topic 'CASCADE CYCLE'

Le manuscrit présente la conversion du dioxyde de carbone en sucres C3 et C4 à l'aide de réactions en cascade chimio-enzymatiques stéréocontrôlées. Le processus repose sur une stratégie en deux étapes avec (i) la réduction catalytique et sélective à 4 électrons du CO2 en un dérivé bis(boryl)acétal suivi (ii) de couplage enzymatique C-C stéréocontrôlé du dérivé bis(boryl)acétal en sucres C3 et C4. La stratégie développée est sans précédent et représente une nouvelle approche pour l'utilisation du CO2 comme source Cn pour la synthèse de biomolécules énantiomériquement pures importantes sur le plan industriel. Le premier chapitre est une étude bibliographique décrivant (i) une introduction à la chimie des sucres avec un focus particulier dédié à la production de sucres à partir de CO2 et de formaldéhyde comme sources C1 et (ii) la réduction sélective et catalytique à quatre électrons du CO2 à l'aide d'hydroborane et d'hydrosilane utilisés comme réducteur pour la formation de dérivés bis(boryl)acétal et bis(silyl)acétal ainsi que leur utilisation comme sources de formaldéhyde ou substituts de formaldéhyde pour la synthèse de produits à haute valeur ajoutée. Le deuxième chapitre présente la synthèse et la réactivité des dérivés bis(boryl)acétal et bis(silyl)acétal. Notamment, un nouveau dérivé bis(boryl)acétal a été synthétisé avec succès et isolé à l'échelle du gramme. Le troisième chapitre décrit la bioconversion stéréocontrôlée du dérivé bis(boryl)acétal synthétisé à partir du CO2 en sucres. Notamment, une réaction enzymatique en cascade a été réalisée pour la production d'un sucre C4 énantiomériquement pur en utilisant le CO2 comme seule source de carbone
The manuscript presents the conversion of carbon dioxide into C3 and C4 carbohydrates using stereocontrolled chemo-enzymatic cascade reactions. The process relies on a two-step strategy with (i) the catalytic and selective 4-electron reduction of CO2 into a bis(boryl)acetal derivative followed by (ii) the stereocontrolled bio-catalyzed C-C coupling of the bis(boryl)acetal derivative into carbohydrates. The strategy developed is unprecedented and represents a new exciting approach for the use of CO2 as a Cn source for the synthesis of valuable industrially relevant enantiomerically pure biomolecules. The first chapter is a bibliographic study describing (i) an introduction to carbohydrate chemistry with a special focus dedicated to the production of carbohydrates from CO2 and formaldehyde as C1 sources and (ii) the selective and catalytic four-electron reduction of CO2 using hydroborane and hydrosilane as reductants for the formation of bis(boryl)acetal and bis(silyl)acetal derivatives and their use as formaldehyde sources or formaldehyde surrogates for the synthesis of value-added product. The second chapter presents the synthesis and reactivity of bis(boryl)acetal and bis(silyl)acetal derivatives. Notably, a new isolable bis(boryl)acetal derivative was successfully synthesized and isolated on a gram scale. The third chapter describes the stereocontrolled bioconversion of the bis(boryl)acetal derivative synthetized from CO2 into carbohydrates. Notably, an enzymatic cascade reaction was performed for the production of an enantiomerically pure C4 carbohydrate using CO2 as the only carbon source

Ces travaux de thèse s’intéressent à une stratégie de fin de vie naissante : le repurposing. Nous le définissons comme un processus industriel par lequel des produits en fin d’usage sont réutilisés dans des applications distinctes. À la fin de leur premier usage, les produits sont réintégrés dans la chaine industrielle en vue d’une nouvelle utilisation dans une autre application. On parle également d’utilisations en cascade. Le but avoué est la conservation de la valeur-ajoutée des produits, aussi longtemps que possible. Cette stratégie s’inscrit aux côtés d’autres stratégies de réutilisation plus connues telles que le réemploi et le remanufacturing.L’illustration principale de la littérature, qui constitue également notre terrain d’étude, concerne les batteries au lithium. Utilisées initialement dans les véhicules électriques, elles sont aujourd’hui recyclées lorsque leurs capacités de stockage diminuent de 20 à 30%. Prolonger leur durée de vie par une seconde application, e.g. un usage stationnaire, permettrait de différer les étapes de recyclage tout en maximisant le maintien de la valeur ajoutée lors de la fabrication. Malgré ces avantages, les exemples de transformations de produits pour des applications en cascade restent à l’état de démonstrateurs, en particulier parce qu’aujourd’hui ces produits et leur chaine de valeur ne sont pas conçus avec des stratégies supportant leur réutilisation.L’objectif de ces travaux est d’apporter aux équipes de conception une vision claire de ce qu’est la stratégie de réutilisation en cascade, de comment l’intégrer lors des étapes amont du processus de conception et de guider l’évaluation environnementale correspondante, afin de les accompagner pour une réelle industrialisation des produits repurposés. En ce sens, nous émettons trois propositions.La première consiste en une classification des caractéristiques propres aux solutions en cascade selon trois axes : le produit, le processus de (re)fabrication et le modèle d’affaire envisagé. À travers ce cadre, nous décrivons les dimensions et les caractéristiques des offres de produits repurposés. Elles sont alors utilisables pour l’établissement de compromis dès les phases amont de conception. Celles-ci sont issues d’une étude bibliographique couplée à des études de terrain.Notre deuxième proposition concerne le processus de conception de tels produits. En effet, plusieurs spécificités sont à prendre en compte en comparaison d’une activité de conception classique : récupération du produit en fin d’usage, applications ultérieures pas ou peu définies, besoins flous, usage influençant les performances, etc. Une étape de conception pour les produits repurposés devra donc être intégrée en amont du processus de repurposing afin d’optimiser les solutions ultérieures. En complément, plusieurs recommandations pour la conception d’un produit repurposé sont formulées. Intégrées au plus tôt, elles visent à faciliter la réutilisation des produits en tenant compte des parties-prenantes, des phases du cycle de vie, des aspects temporels et en gérant mieux l’information.Enfin, un cadre générique structurant la réalisation d’analyses du cycle de vie de ces solutions est proposé. Les ACVistes pourront ainsi plus facilement tenir compte des spécificités de ces stratégies, car la complexité des modélisations ACV pour les produits aux applications en cascade nécessite davantage de rigueur et de précision que pour des produits à application unique. Pour supporter ce cadre, trois recommandations à destination des équipes de conception sont émises. Elles permettent la formalisation d'éléments de contexte pour améliorer la comparaison avec d’autres études et d’informations en vue des analyses de sensibilité.Ces trois propositions sont implémentées sur deux cas d’étude ‘batterie’, au cours de séances de travail regroupant des parties-prenantes de l’ensemble du cycle de vie : commanditaire, équipes de conception, logisticiens, recycleur, etc
This PhD dissertation focuses on an innovative end-of-life strategy: repurposing. We define ‘repurposing’ as a manufacturing process through which products nearing their end-of-life are reused in different applications. At the end of their intended use, products are reintegrated into the manufacturing chain and adapted for their next application. We also refer to this strategy as cascading application reuse (CAR). The main purpose of CAR is the preservation of the added-value of such products. This strategy is in line with other reuse strategies such as direct reuse and remanufacturing.The central illustration in our case study addresses lithium-ion batteries used in electric vehicles, which are recycled when the battery’s charging capacity falls below 80%. Extending the component lifespan with a second application, e.g. stationary application, postpones introduction into the waste stream, retaining the added-value from the original manufacturing process. Despite these advantages, examples of product adaptation for CAR remain at a proof-of-concept scale - currently these products and their value chains are not yet designed with strategies supporting reuse.The objective of this research is to provide a clear vision to design teams about repurposing strategies, how to integrate the strategies during the upstream stages of the design process and how to facilitate the corresponding lifecycle assessment. The objective is to support designers during the manufacturing of repurposed products. We make three proposals.The first consists of classifying the characteristics specific to the repurposing strategy according to three axes: the product, the (re)manufacturing process and the business model. Through this framework, we describe the dimensions and characteristics of what the repurposed product offers, which are integral during the design activity. These attributes are the result of a study of the relevant literature coupled with several field investigations.Our second proposal concerns the design process for such products. Indeed, several differences with classical design practices appear: the need for product recovery at the end of use, subsequent applications and needs not fully defined, which affect performance, etc. A design stage for repurposed products must therefore be integrated before subsequent applications in order to optimise redesign solutions. Integrated as early as possible, they aim to facilitate product reuse by taking into account stakeholders, life cycle phases, time aspects and better information management.Finally, a generic framework structuring the carrying out of life cycle analyses of repurposing is proposed. This will simplify the inclusion of their specificities for life cycle assessments (LCA) practitioners. Indeed, the complexity of LCA modelling for cascading applications products requires more rigour and precision than single application products. To support this framework, three recommendations for design teams are made, the objective of which is to better formalise the information from the design process. These recommendations support the formalisation of contextual elements to improve comparison with other studies and the organisation of information for sensitivity analyses.These three proposals are implemented on two battery case studies, during working sessions involving stakeholders representing the complete life cycle: sponsor, design teams, logisticians, recycler, etc

Ce travail est centré sur l'étude des mécanismes d'induction et de répression des signaux mitogènes et de motilité des hépatocytes. Le blocage de la prolifération et de la survie des cellules transformées représente un enjeu important dans le développement de traitement anti-cancéreux. Cet objectif, nous a conduit à : 1/ préciser l'implication de la voie MEK/ERK dans l'équilibre prolifération / motilité et démontrer l'incidence de MLCK dans l'intégration des signaux mitogènes dans les hépatocytes normaux ; 2/ analyser les mécanismes MEK/ERK dépendants, régulant la motilité et la prolifération des cellules issues d'hépatocarcinomes ; 3/ appréhender plusieurs techniques d'imagerie afin de visualiser au mieux la tumeur induite suite à l'injection de cellules cancéreuses en ectopique et en orthotopique. Toutes les informations obtenues à l'issue de ces différentes approches devraient nous permettre un meilleur suivi de la croissance tumorale in vivo et de définir de nouvelles cibles thérapeutiques.

Ces travaux de thèse ont permis dans un premier temps, d'aborder différentes voies de synthèse d'un nouvel antipsychotique potentiel (F17464) proposé par les laboratoires Pierre Fabre. Trois stratégies basées sur des synthèses convergentes ont été initiées. La première stratégie repose sur une étape clé de métathèse croisée, la seconde sur une réaction de Sonogashira et la troisième aborde une nouvelle méthodologie d'alkylation des chromones en position 3. Ces méthodes nous ont permis d'accéder à des intermédiaires de synthèse originaux, utiles pour préparer la molécule F17464 en respectant les contraintes industrielles.Dans un deuxième temps, différents types de molécules polycycliques complexes ont été synthétisés par cascades réactionnelles palladocatalysées. Une série de naphtalènes condensés a été préparée par réaction domino palladocatalysée issue de cyclocarbopalladations successives suivies d'une activation C(sp2)-H. Plusieurs types de cycles à sept atomes de carbone condensés ont été synthétisés en une seule étape, à partir de substrats faciles d'accès, via des cascades réactionnelles cyclocarbopalladations/activation C(sp2) ou C(sp3)-H.Finalement, des cyclooctatriènes et des fenestradiènes ont été obtenus à partir du même substrat,en une seule étape, via des réactions en cascade débutant par une cyclocarbopalladation 4-exodigsuivie d'un couplage de Stille puis d'une addition d'alcynes sur une triple liaison s'achevant par des réactions d'électrocyclisations. La température est le seul paramètre réactionnel qui diffère dans la synthèse de ces deux polycycles complexes, à partir du même substrat
This PhD thesis allowed us in the first part to develop different synthesic pathways to a new potential antipsychotic (F17464) invented by Pierre Fabre laboratories. Three strategies based on convergent syntheses are initiated. The key step of the first strategy is olefin cross metathesis. The second strategy rests on Sonogashira coupling and the third one involves a new methodology ofchromones alkylation in position 3. These methods allowed us access to novel synthetic intermediates, useful in the preparation of the F17464 molecule by following industrial confines.ln the second part, different types of polycyclic molecules were synthesized by palladium-catalyzed cascade reactions. A set of fused naphthalenes was prepared by palladium-catalyzed dominoreaction including cyclocarbopalladations followed by C(sp2)-H bond activation. Several types of fused seven-membered carbocycles were synthesized in a one-pot reaction from convenient substrates, via cascade reactions including cyclocarbopalladations followed by C(sp2 or sp3)-Hbond activation. Finally, cyclooctatrienes and fenestradienes were obtained also in a one-pot reaction from the same substrate via cascade reactions involving 4-exo-dig cyclocarbopalladation, followed by Stille coupling, alkyne addition onto a triple bond, finishing by electrocyclization reactions. Temperature is the only parameter that differs in the synthesis ôf the two complex polycycles starting from the same substrate

Les émissions du CO2 sont en hausse, provoquant vraisemblablement une augmentation de la température du Globe; ceci a conduit au Protocole de Kyoto qui vise à élaborer des politiques de limitation des émissions de gaz à effet de serre dont le CO2. De nombreuses options existent pour limiter les émissions de CO2 liées à la production d'énergie dont l'une fait l'objet de cette thèse, la capture du CO2 sur les fumées. Les techniques usuelles de capture du CO2 sont analysées assez rapidement. La plus grande partie du travail vise à élaborer cette nouvelle méthode de capture basée sur le givrage du CO2 à basse température. Le givrage du CO2 est accompli par un système frigorifique, dit en cascade intégrée, offrant des températures d'évaporation inférieures à la température de givrage du CO2. Plusieurs architectures sont étudiées afin de choisir celle qui apparaît la plus efficace énergétiquement. Une maquette prototype a été conçue et réalisée pour valider l'ensemble des concepts sur le givrage et le dégivrage du CO2. Le dimensionnement des composants a été réalisé à l'aide de modèles informatiques développés pour modéliser des cascades intégrées multi-étagées. Le système possède 2 évaporateurs basse température fonctionnant alternativement en givrage et dégivrage afin de permettre un fonctionnement continu du système. L'énergie "froide" du dégivrage est récupérée par le mélange de fluides frigorigènes, ce qui permet d'améliorer l'efficacité énergétique du système
Missions of CO2 are increasing, leading to temperature increase of Earth. This led to the Kyoto Protocol which aims at the elaboration of policies of limitation of the emissions of greenhouse gases among which CO2. A large number of options exist to limit CO2 emissions associated with energy production, one of them is developed in this dissertation, the CO2 capture from flue gases. Usual techniques of CO2 capture are briefly analyzed. The major part of this work concerns the development of a new CO2 capture based on the CO2 frosting at low temperature. The CO2 frosting is performed by a refrigerating system composed of an integrated cascade, which offers evaporating temperatures lower than the CO2 frosting temperature. Several architectures are analyzed in order to choose the most energy efficient one. A prototype mock-up has been designed and realized for the validation of the global concepts of the CO2 frosting and defrosting. The components have been sized using computerized tools developed for the modeling of multi-stage integrated cascades. The system includes two low-temperature evaporators operating alternatively in frosting and defrosting modes to permit continuous system operation. The "cold" energy from defrosting is recovered by the refrigerant blend, which permits to improve the energy efficiency of the system

Etude experimentale et simulation dynamique de systemes de pompe a chaleur a adsorption solide. Les systemes methanol-charbon actif et eau-zeolite sont etudies. Les conditions de temperature des composants (adsorbeur, condenseur et evaporateur) doivent etre homogenes pour la simulation. On considere les cycles intermittents (simple effet), a double effet et a triple effet (cycle a cascades). Determination d'un coefficient de performance pour la production du froid

The master's thesis deals with district heat exchangers in a thermal steam cycle of combined heat and power plants and with types of condensate cascades in the multilevel heating systems. Calculation of the thermal efficiency of electricity generation is provided for the investigated thermal cycle, which was modified for three different types of cascades. Besides that, a comparison of useful electric power and electricity generation through one year period of working is made. A significant part of the work is devoted to the design of district heat exchangers, including the calculation of thermal power and heat transfer area. Main dimensions are proposed for each exchanger together with a basic drawing.

Die vorliegende Arbeit beschäftigt sich nach der Analyse und Optimierung der Stromzuführungen auf Flüssigstickstoff-Temperaturniveau, hauptsächlich mit der Untersuchung einer Gemisch-Stickstoff-Kaskade als Kälteversorgungssystem eines resistiven HTSL-Kurzschlussstrombegrenzers. Unter einem Kurzschlussstrombegrenzer versteht man einen veränderlichen elektrischen Widerstand, welcher, gegebenenfalls in Serie mit konventionellen, mechanischen Stromunterbrechern, direkt in den zu schützenden Stromkreis eingebaut ist. Als veränderlicher elektrischer Widerstand kann z.B. ein supraleitendes Element verwendet werden. Im normalen Betriebsfall setzt dieser dem fließenden Strom praktisch keinen Widerstand entgegen. Die Dimensionierung wird so gewählt, dass im Falle eines Überstroms ein rascher Übergang in den normalleitenden Zustand erfolgt. Durch den nun vorhandenen Widerstand wird der Stromfluss sehr effektiv begrenzt, bis beispielsweise nachgeschaltete mechanische Schutzeinrichtungen ansprechen. Sobald dies erfolgt ist, kann der Supraleiter regenerieren und in den Ausgangszustand zurückkehren. Die Verwendung von HTSL-Material als Supraleiter erscheint hier höchst vorteilhaft, da damit ein Arbeiten auf Flüssigstickstoff-Temperaturniveau erlaubt wird. Ein entscheidender Punkt für die erfolgreiche Einführung der HTSL-FCL ist die Bereitstellung einer geeigneten Kälteversorgung. Dies kann entweder durch regelmäßiges Nachfühlen mit flüssigem Stickstoff oder durch den Einsatz einer Kältemaschine zur Stickstoffrekondensation realisiert werden. Beim Einsatz einer Kältemaschine hat man einen von der Stickstoffnachlieferung unabhängigen Betrieb mit geschlossenem Kühlsystem. Die Energiedissipation in dem HTSL-Element selbst ist unter Normalbedingungen vernachlässigbar klein. Für die Auslegung des Kühlsystems ist von Bedeutung, dass der größte Teil der Wärmelast durch die metallischen Stromzuführungen verursacht wird. Die Auslegung des Kühlsystems muss sich daher an der thermodynamischen Analyse der Stromzuführungen orientieren. Das Ziel dieser Arbeit bestand in der Analyse von Kühlmethoden für solche Stromzuführungen hinsichtlich ihrer Effektivität und Wirtschaftlichkeit. Ein neues Kühlsystem auf der Basis einer Gemisch-Stickstoff-Kaskade wird vorgeschlagen als Alternative zu den derzeit in Frage kommenden Kühltechniken. Es wurde folgende Vorgehensweise gewählt: 1. Verschiedene Kühlmethoden zur Kühlung von SZF werden aufgeführt und thermodynamisch bewertet. 2. Kühlsysteme, basierend auf einer Gemisch-Stickstoff-Kaskade, werden vorgeschlagen und deren Charakteristika mittels numerischer Simulation bestimmt. 3. Ein auf der Basis einer Gemisch-Kältemaschine gebauter Stickstoffverflüssiger wird in Betrieb genommen und getestet. 4. Die Funktion und die Effektivität der Gemisch-Stickstoff-Kaskade zur Kühlung der Stromzuführungen werden bewertet. 5. Zugehörige Kühlsysteme auf der Basis verschiedener Kühltechniken werden analysiert 6. In einer Wirtschaftlichkeitsbetrachtung werden die Kühlsysteme einander gegenübergestellt Insgesamt kann als Ergebnis festgehalten werden, dass der Einsatz der vorgestellten Gemisch-Stickstoff-Kaskadenanlagen zur Kälteversorgung im vorgestellten Anwendungsfall eine durchaus wettbewerbsfähige, voraussichtlich sogar überlegene Alternative zu den sonst verfügbaren Methoden darstellt.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Dr. Srinivas Garimella; Committee Member: Dr. Samuel Graham; Committee Member: Dr. Sheldon Jeter. Part of the SMARTech Electronic Thesis and Dissertation Collection.

This thesis focuses on addressing some important aspects of the life cycle of interstellar clouds through observational submillimeter and millimeter-wave studies of star formation and molecular cloud environments and the development of instrumentation to enable these studies.We examine the influence of star formation on parent molecular clouds through a case study of protostellar sources in the Mon OB1 northern cloud complex. An energetics analysis of these star forming regions and associated molecular outflows was carried out, suggesting that the cloud complex maintains its overall integrity, except along outflow axes and that the coupling between outflow kinetic energy and cloud turbulent energy is weak, < ~0.5%. In order to study the larger picture of cloud formation and disruption, this work was expanded to explore the molecular environment at cloud boundaries. To this end, acloud edge survey was undertaken consisting of multi-transition strip scan observations of CO and 13CO toward molecular clouds with a broad range of stellar and star forming characteristics. Our work supports the interpretation that cloud formation is taking place along the southeastern edge of Heiles Cloud 2, and the results will be used as a framework for guiding the analysis of other surveyed cloud edges.Achieving observational capabilities enabling effective studies of life cycles of the ISM is becoming possible through a new generation of heterodyne spectroscopic instruments. Here, we report on characterization measurements of a prototype mixer unit for the 64-pixel SuperCam array, an instrument commissioned to mapover 500 square degrees of the Galactic Plane with very high resolution at 345 GHz. These measurements were crucial to verifying the overall array design and anticipating its performance. Spectroscopic capabilities at THz (< 300 microns) frequencies permits access to a host of diagnostic tools (e.g., high-J CO, CI, NII, & CII) uniquely suited to probe crucial properties of the ISM. The development of heterodynetechnology at these frequencies is largely limited by availability of compact, powerful sources of local oscillator power. We explore the use of waveguide spatial filters in conjunction with Quantum Cascade Lasers, a promising power source at frequenciesabove ~ 2 THz.

Die vorliegende Arbeit beschäftigt sich nach der Analyse und Optimierung der Stromzuführungen auf Flüssigstickstoff-Temperaturniveau, hauptsächlich mit der Untersuchung einer Gemisch-Stickstoff-Kaskade als Kälteversorgungssystem eines resistiven HTSL-Kurzschlussstrombegrenzers. Unter einem Kurzschlussstrombegrenzer versteht man einen veränderlichen elektrischen Widerstand, welcher, gegebenenfalls in Serie mit konventionellen, mechanischen Stromunterbrechern, direkt in den zu schützenden Stromkreis eingebaut ist. Als veränderlicher elektrischer Widerstand kann z.B. ein supraleitendes Element verwendet werden. Im normalen Betriebsfall setzt dieser dem fließenden Strom praktisch keinen Widerstand entgegen. Die Dimensionierung wird so gewählt, dass im Falle eines Überstroms ein rascher Übergang in den normalleitenden Zustand erfolgt. Durch den nun vorhandenen Widerstand wird der Stromfluss sehr effektiv begrenzt, bis beispielsweise nachgeschaltete mechanische Schutzeinrichtungen ansprechen. Sobald dies erfolgt ist, kann der Supraleiter regenerieren und in den Ausgangszustand zurückkehren. Die Verwendung von HTSL-Material als Supraleiter erscheint hier höchst vorteilhaft, da damit ein Arbeiten auf Flüssigstickstoff-Temperaturniveau erlaubt wird. Ein entscheidender Punkt für die erfolgreiche Einführung der HTSL-FCL ist die Bereitstellung einer geeigneten Kälteversorgung. Dies kann entweder durch regelmäßiges Nachfühlen mit flüssigem Stickstoff oder durch den Einsatz einer Kältemaschine zur Stickstoffrekondensation realisiert werden. Beim Einsatz einer Kältemaschine hat man einen von der Stickstoffnachlieferung unabhängigen Betrieb mit geschlossenem Kühlsystem. Die Energiedissipation in dem HTSL-Element selbst ist unter Normalbedingungen vernachlässigbar klein. Für die Auslegung des Kühlsystems ist von Bedeutung, dass der größte Teil der Wärmelast durch die metallischen Stromzuführungen verursacht wird. Die Auslegung des Kühlsystems muss sich daher an der thermodynamischen Analyse der Stromzuführungen orientieren. Das Ziel dieser Arbeit bestand in der Analyse von Kühlmethoden für solche Stromzuführungen hinsichtlich ihrer Effektivität und Wirtschaftlichkeit. Ein neues Kühlsystem auf der Basis einer Gemisch-Stickstoff-Kaskade wird vorgeschlagen als Alternative zu den derzeit in Frage kommenden Kühltechniken. Es wurde folgende Vorgehensweise gewählt: 1. Verschiedene Kühlmethoden zur Kühlung von SZF werden aufgeführt und thermodynamisch bewertet. 2. Kühlsysteme, basierend auf einer Gemisch-Stickstoff-Kaskade, werden vorgeschlagen und deren Charakteristika mittels numerischer Simulation bestimmt. 3. Ein auf der Basis einer Gemisch-Kältemaschine gebauter Stickstoffverflüssiger wird in Betrieb genommen und getestet. 4. Die Funktion und die Effektivität der Gemisch-Stickstoff-Kaskade zur Kühlung der Stromzuführungen werden bewertet. 5. Zugehörige Kühlsysteme auf der Basis verschiedener Kühltechniken werden analysiert 6. In einer Wirtschaftlichkeitsbetrachtung werden die Kühlsysteme einander gegenübergestellt Insgesamt kann als Ergebnis festgehalten werden, dass der Einsatz der vorgestellten Gemisch-Stickstoff-Kaskadenanlagen zur Kälteversorgung im vorgestellten Anwendungsfall eine durchaus wettbewerbsfähige, voraussichtlich sogar überlegene Alternative zu den sonst verfügbaren Methoden darstellt.

Orientador: Jose Vicente Hallak D'Angelo
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: O comércio de gás natural liquefeito apresenta um crescente interesse por parte tanto de países exportadores como dependentes desta fonte energética. Apesar de o transporte por gasoduto ser muito menos suscetível a perdas, ele se torna inviável a longas distâncias ou a demandas variáveis. A liquefação do gás natural também proporciona o armazenamento desta fonte energética numa forma estável e de alto potencial energético,evidenciando o caráter estratégico do processo. Desde a década de 60 a tecnologia para liquefação do gás natural é utilizada, porém, apenas há alguns anos os países iniciaram o comércio desta fonte energética em larga escala e isto acarretará um aumento mundial tanto no número de terminais exportadores (plantas de liquefação) quanto importadores (terminais de regaseificação). O processo de liquefação do gás natural ocorre através de uma sequência de ciclos termodinâmicos de refrigeração, e estes, por sua vez, precisam trabalhar de forma otimizada para reduzir perdas. A análise exergética é uma ferramenta muito útil para avaliar estas perdas e pode ser essencial na instalação de uma nova planta ou melhoria de uma já existente. O presente trabalho realizou uma análise exergética de um ciclo de refrigeração utilizado para a liquefação de gás natural, o qual é do tipo multiestágio em cascata, padrão utilizado atualmente, sendo o mais conhecido e difundido entre as indústrias da área. Primeiramente, o processo foi simulado em software comercial Hysys (versão 3.2 da Aspen Technology). O resultado obtido da simulação foi validado através de comparação com dados da literatura, mostrando-se adequado. Em seguida, a simulação foi testada em diferentes condições operacionais, seguindo um planejamento fatorial completo, o qual teve como objetivo verificar a influência da variação das pressões de seis pontos específicos do ciclo sobre a variável resposta, que é a taxa de exergia total destruída no processo, visando sua minimização. Os resultados obtidos levaram a uma nova condição de operação para o ciclo de refrigeração com redução de aproximadamente 48% da taxa de exergia destruída com relação aos dados do caso obtido da literatura. Tal resultado evidencia o potencial da metodologia termodinâmica utilizada, demonstrando sua aplicação em estudos de melhoria do desempenho de ciclos de refrigeração para a indústria de liquefação de gás natural
Abstract: The liquefied natural gas trade shows a growing interest either from countries which are exporters or countries which depend on this kind of energetic source. Although gas pipelines are less susceptible of transportation losses, they become impracticable when distances are too long or when demands are highly variable. The liquefaction of natural gas also enables its storage in a stable way, in which energetic potential is high, expressing the strategic purpose of the process. Since the 1960 decade natural gas liquefying technology is been used, but only a few years ago countries have started the trade of this kind of energetic source on a large scale. Consequently, the number of exporter terminals (liquefaction industries) and importer terminals (regasification plants) will increase worldwide. The natural gas liquefaction process is based on a sequence of refrigeration thermodynamics cycles, which need to work in an optimized way in order to reduce losses. The exergy analysis is a very useful tool to evaluate these losses and can be crucial in a new plant installation or in a current one improvement. This dissertation performed an exergy analysis of a multistage cascade refrigeration cycle applied in natural gas liquefaction. The multistage cascade cycle is currently the standard type, being the most known and diffused among industries. Firstly, the process was simulated in commercial software Hysys (version 3.2 of Aspen Technology). The result obtained from the simulation was validated by comparison with the literature data and showed a very adequate similarity. After that, the simulation was checked in different operational conditions, according to the complete factorial design of experiments. The design of experiments¿ objective was to verify the pressure influence of six specific points of the cycle over the response variable, which is the rate of total exergy destroyed in the cycle, in order to reach its minimal value. The results showed a new operational condition to the refrigeration cycle, in which the destroyed exergy rate was reduced by approximately 48% in comparison with literature data. This result provides evidence of the high potential of the thermodynamic tool used, showing its application in studies of performance improvements for refrigeration cycles in industries of natural gas liquefaction
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química

Utility Computing is one of the most discussed business models in the context of Cloud Computing. Service providers are more and more pushed into the role of utilities by their customer's expectations. Subsequently, the demand for predictable service availability and pay-per-use pricing models increases. Furthermore, for providers, a new opportunity to optimise resource usage offers arises, resulting from new virtualisation techniques. In this context, the control of service quality and profit depends on a deep understanding of the representation of the relationship between business and technique. This research analyses the relationship between the business model of Utility Computing and Service-oriented Computing architectures hosted in Cloud environments. The relations are clarified in detail for the entire service life cycle and throughout all architectural layers. Based on the elaborated relations, an approach to a delivery framework is evolved, in order to enable the optimisation of the relation attributes, while the service implementation passes through business planning, development, and operations. Related work from academic literature does not cover the collected requirements on service offers in this context. This finding is revealed by a critical review of approaches in the fields of Cloud Computing, Grid Computing, and Application Clusters. The related work is analysed regarding appropriate provision architectures and quality assurance approaches. The main concepts of the delivery framework are evaluated based on a simulation model. To demonstrate the ability of the framework to model complex pay-per-use service cascades in Cloud environments, several experiments have been conducted. First outcomes proof that the contributions of this research undoubtedly enable the optimisation of service quality and profit in Cloud-based Service-oriented Computing architectures.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Estado do Paraná (FA)
Considering the theor etical and political aspects present in the Scholarship Programs for Beginner Teachers (PIBID), the current paper aims to present a panoramic view of the Teachers Education Policy in Luis Inácio Lula da Silva (2003 - 2010), and Dilma Rousseff (2014/Michel Temer) government, regarding to understand the moviments that are intertwined in a contradictory way in the current reality, as remnants of the previous governments. In relation to the PIBID, as na educational policy for teacher seducation, we seek to analyzeifthe policies that support the program explain some doctrine, thusunderlining a the oreticaland political-pedagogical orientation; how the PIBID was implemented at UNIOESTE Cascavel campus, in order tounderstand the ways, the limits, the existing contradictions, as well as the meanings that are produced by this policy focused on teachers education. In methodological terms for the realization of this research we will firstest ablish the accomplishment of a bibliograp hicre search, ming besides the definition of themost important concepts, the necessary basist o the ful fillmento the first objectives. The before, the theoretical-methodological consideration swere guided through “the political-cycle approach”by Stephen Ball, who chis opposed to a traditional analysis. This approach is in tended to understand the structuring movement scarried out by the policy, identifying the element that constituteit so that we can understand eachoftho se elements particular lyrelated to the historical conjuncture materialisati on of Brazilian public educational policy. As in instrument of data collection for the accomplishment of this research semi-structured interviews were used, as well as a structured questionnaire, hosted on Google Forms platform, through na access link. For the analisy sof the obtained data, the oreticaland political aspects were considered whichin fluenced in a director indirect manner the objective of this work, thus allowing to discuss the practical work conditions that directly influence in the program effectiveness.
Considerando os aspectos teóricos e políticos presentes no Programa de Bolsas de Iniciação a Docência (PIBID), o presente trabalho tem por finalidade apresentar uma visão panorâmica da Política de Formação de Professores no governo Luis Inácio Lula da Silva (2003 a 2010), e Dilma Rousseff (2014/ Michel Temer), a fim de que possamos compreender os movimentos que se entrelaçam de forma contraditória na realidade atual, como resquícios dos governos anteriores. Em relação ao PIBID, enquanto política educacional de formação de professores, buscamos analisar se as políticas que fundamentam o programa explicitam alguma doutrina, demonstrando dessa forma uma orientação teórica e político-pedagógica; como o PIBID foi implementado na UNIOESTE campus Cascavel, a fim de compreender os caminhos, descaminhos, os limites, as contradições existentes, bem como os sentidos que são produzidos por essa política voltada a formação de professores. Em termos metodológicos para a efetivação desta pesquisa primeiramente nos pautaremos na realização de uma pesquisa bibliográfica visando além da definição dos conceitos mais importantes, o embasamento necessário ao cumprimento dos primeiros objetivos. Nesse sentido pautamos nossas considerações teórico-metodológicas, na “abordagem do ciclo de políticas” de Stephen Ball, a qual é apresentada como uma contraposição a uma análise tradicional tendo como intenção compreender os movimentos de estruturação realizados pela política, identificando os elementos que a constituem de forma que compreendamos cada um destes elementos especificamente relacionados à conjuntura histórica da materialização da política pública educacional brasileira. Como instrumento de coleta de dados foram utilizadas entrevistas semiestruturadas, bem como um questionário estruturado, hospedado na plataforma Google Forms, por meio de um link de acesso. Para a análise dos dados obtidos, foram considerados aspectos teóricos e políticos que influenciaram de maneira direta ou indireta o objetivo deste trabalho, permitindo assim discutir as condições objetivas de trabalho que influenciam diretamente na efetivação do programa.

Lo studio descritto in questa tesi riguarda l’analisi di diverse soluzioni di layout per lo sfruttamento di un cascame termico, al fine di produrre potenza elettrica. Questa sorgente di calore è rappresentata da una corrente di prodotti di combustione emessa da una turbina a gas, con temperatura superiore a 550 °C. Tale condizione ha indotto a prendere in considerazione innovative applicazioni della tecnologia ORC (Organic Rankine Cycle), da tempo impiegata nel mercato del recupero di calore, ma che trova il suo principale limite nella massima temperatura di esercizio dei fluidi di lavoro. Infatti, tradizionalmente gli impianti ORC sono adottati in abbinamento a sorgenti di calore con temperature inferiori a 500 °C, quindi il caso proposto in questo studio rappresenta una sfida per la tecnologia ORC e per i fluidi impiegati. Pertanto, all’interno di questa tesi viene mostrato un confronto, sia dal punto di vista prestazionale sia dal punto di vista di parametri attinenti al costo e alla complessità impiantistica, tra un sistema energetico di nuova concezione configurato con due cicli in cascata, che implementa la cosiddetta tecnologia VHT-ORC (Very High Temperature ORC), e altre soluzioni da più tempo disponibili sul mercato.

Increasing the efficiency of conventional power plants is a crucial aspect in the quest of reducing the energy consumption of the world and to having sustainable energy systems in the future. Thus, within the scope of this thesis the possible efficiency improvements for the Wärtsilä 18V50DF model gas engine based combine power generation options are investigated by recovering waste heat of the engine via Organic Rankine cycle (ORC).  In order to this, four different ORC models are simulated via Aspen Plus software and these models are optimized for different objective functions; power output and price per unit of electricity generation. These ORC models are: regenerative Organic Rankine cycle (RORC), cascaded Organic Rankine cycle with an economizer (CORCE), cascaded Organic Rankine cycle with two heat sources (CORC2) and cascaded Organic Rankine cycle with three heat sources (CORC3). In the cascaded cycle models there are two loops which are coupled with a common heat exchanger that works as a condenser for the high temperature (HT) loop and as a preheater for the low temperature (LT) loop. By using this common heat exchanger, the latent heat of condensation of the HT loop is utilized. The engine’s hot exhaust gases are used as main heat source in all the ORC models. The engine’s jacket water is utilized in the CORC2 models as an additional heat source to preheat the LT working fluid. In the CORC3 models engine’s lubrication oil together with the jacket water are used as additional sources for preheating the LT loop working fluid. Thus, the suitability of utilizing these two waste heat sources is examined. Moreover, thermodynamic and economic analyses are performed for each model and the results are compared to each other. The effect of different working fluids, condenser cooling water temperatures, superheating on cycles performance is also evaluated. The results show that with the same amount of fuel the power output of the engine would be increased 2200 kW in average and this increases the efficiency of the engine by 6.3 %. The highest power outputs are obtained in CORC3 models (around 2750 kW) whereas the lowest are in the RORC models (around 1800 kW). In contrast to the power output results, energetic efficiencies of the RORC models (around 30 %) are the highest and CORC3 models (around 22 %) are the lowest. In terms of exergetic efficiency, the highest efficiencies are obtained in CORC2 (around 64.5 %) models whereas the lowest in the RORC models (around 63 %). All the models are found economically feasible since thermodynamically optimized models pay the investment costs back in average of 2 years whereas the economically optimized ones in 1.7. The selection of the working fluid slightly affects the thermodynamic performance of the system since in all the ORC configurations Octamethyltrisiloxane (MDM) working fluid cycles achieve better thermodynamic performances than Decamethyltetrasiloxane (MD2M) working fluid cycles. However, the choice of working fluid doesn’t affect the costs of the system since both working fluid cycles have similar price per unit of electricity generation. The CORC2 models obtain the shortest payback times whereas the CORC3 models obtain the longest Thus the configuration of the ORC does affect the economic performance. It is observed from the results that increasing the condenser cooling water temperature have negative impact on both thermodynamic and economic performances. Also, thermodynamic performances of the cycles are getting reduced with the increasing degree of superheating thus superheating negatively affects the cycle’s performances. The engine’s jacket water and lubrication oil are found to be sufficient waste heat sources to use in the ORC models.

Orientador: Caio Glauco Sanchez
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica.
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Resumo: Hoje no mundo há uma grande rejeição de matériais, resíduos e outros compostos orgânicos que podem ser aproveitados como fontes de energia. Exemplos podem ser observados em todo o mundo e principalmente em regiões onde a pobreza impera e que a energia elétrica pode ser de grande ajuda ou mesmo como um salva vidas. O emprego de pequenas centrais de geração de potencia integradas a um gaseificador comum motor de combustão interna (Integrated Gasefication Combustion EngineI GCE) do ciclo OTTO e adaptado para operar com gás de baixo poder calorífico, constitui uma alternativa interessante e economicamente viável,que possibilita a produção independente de energia elétrica e térmica (Marcelo,2004). Para o aproveitamento de resíduos de BIOMASSA,como a casca de arroz, utilizou-se um processo de gaseificação,que é uma técnica que possibilita o uso energético da biomassa através da obtenção de um gás de baixo poder calorífico (4a6 MJ/Nm33). Utilizou-se um gaseificador de leito fluidizado do Laboratório de combustão da FEM,onde foi instalado um motor de 5965 litros de cilindrada total e 6 cilindros, com taxa de compressão 12:1, do ciclo OTTO, que originalmente é utilizado em veículos movidos a gás natural comprimido. Obteve se os seguintes valores nos ensaios: Potência (kW)=40.7@ 1800 rpm, Avanço(Graus do virabrequim )=30;Temperatura de Escapamento (°C) =596; Lambda =1,12; Pressão Máxima de Combustão (PA) =4000000. Como funcionamento do motor, verificou se a necessidade de algumas alterações em seus componentes, como também mudanças nas regulagens de avanço. É necessário um sistema para aumentar a pressão do gás proveniente do gaseificador e um sistema de partida inicial. Dessa maneira teríamos um motor para operar como grupo gerador e fazer parte de uma planta piloto para geração de energia elétrica por gaseificação de biomassa
Abstract: Nowadays there is a great waste of organic matters, residues and other substances that could be used in a power plant. Examples can mainly be observed in the whole world and in regions where the poverty reigns and where the electric energy could be of great aid.The use of small power generation plants integrated to a gasification with an internal combustion engine (Integrated Gasification Combustion Engine-GCE) of cycle OTTO and adapted to operate with low power heat rate gas, consists an interesting and economical viable alternative, that makes possible the independent production of electric and thermal energy. For the exploitation of residues of BIOMASS, as the rice husk, we used a gasification process that is a form to increase the energy use of the biomass. The gasification can generate thermal energy and electric energy. It was used gasifier of fluidized bed from UNICAMP, where it was installed an engine with of 5,965 liters and 6 cylinders, with compression rate 12:1(cycle OTTO),which was originally used in vehicles powered by compressed natural gas, to running with the gas of low power heat rate (46 MJ/Nm3) produced by gasifier. Typical experimental result. Power (kW)=40,7@1800rpm; Advance (Degrees)=30; Exhaust gas temperature(°C)=596; Lambda=1,12; Maximum Combustion Pressure (PA)=4000000. During the running of the engine, the necessity of some alterations in some components was verified as well changes in the advance regulations. A system to increase the pressure of the gas proceeding from the gasifier and a system of start are necessary. In this way we would have an engine to operate as generating group and to be part of a pilot plant for generation of eletric energy for gasification of biomass in agricultural and interior cities
Mestrado
Termica e Fluidos
Mestre em Engenharia Mecânica

This study was performed with the objective of assessing the effects of direct inclusion of 0%, 1%, 1.5% and 2% of the alga Lithothamnium calcareum in the diet, the age hen and interaction between these variables on the production and egg shell quality of laying hens in the second cycle. A completely randomized design was used with subdivided portions (inclusion level: 0%, 1%, 1.5% and 2% x age: 112, 114, 116 and 118 weeks of age) with 6 replications, 10 hens per experimental unit. Each replications of the experiment involved use of 10 Dekalb White hens lines with an age of 110 weeks, four eggs being collected during each period. Percentage of eggs, percentage of broken eggs, percentage of cracked eggs, egg weight; yolk weight, white weight, eggshell weight, specific gravity, percentage eggshell, shell thickness ; number of shell pores; percentage of mineral matter eggshell, percentage of calcium and phosphorus in eggshell were measured and means were compared by Scott-Knott 5% test. The inclusion level of the alga increased the percentage of egg, shell thickness, percentage of mineral matter eggshell and calcium and decreased percentage of cracked eggs and number of pores in the shell. The increasing age of the laying hens decreased eggs shell quality. It was concluded that inclusion levels of Lithothamnium calcareum increased production and egg shell quality.
Objetivou-se avaliar os efeitos da inclusão direta na ração de 0, 1%, 1,5% e 2% da alga Lithothamnium calcareum, a idade da ave e a interação entre eles sobre a produção e a qualidade da casca de ovos de poedeiras comerciais de segundo ciclo. O experimento foi realizado em delineamento inteiramente casualizado em esquema de parcelas subdivididas (nível de inclusão: 0, 1%, 1,5% e 2% x idades: 112, 114, 116 e 118 semanas de idade) com seis repetições. Cada repetição foi composta de 10 aves da linhagem Dekalb White alojadas com 110 semanas de idade. Em cada idade foram coletados quatro ovos de cada repetição. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Scott-Knott 5%. As características avaliadas foram: percentagem de postura, ovos trincados e quebrados, peso dos ovos, gravidade especifica, percentagem de casca, peso da gema, clara e casca, matéria mineral da casca, espessura da casca, número de poros da casca, percentagem de cálcio e fósforo da casca. O nível de inclusão da alga aumentou a percentagem de postura, a espessura da casca, a percentagem de matéria mineral e de cálcio da casca, e diminuiu percentagem de ovos trincados e número de poros da casca. O aumento da idade das aves determinou a diminuição da qualidade da casca dos ovos. Conclui-se que os diferentes níveis de inclusão da alga Lithothamnium calcareum melhoram a produção e a qualidade externa dos ovos.
Mestre em Ciências Veterinárias

A thermodynamic analysis is done for cascade cycle which is a combination of vapour compression system with vapour absorption system. The objective of the work is to determine the effects of different parameters on the performance of the cycle. Equations used follow the first law of thermodynamics. Capacity of the cascade cycle is taken as 50 kw. Refrigerants used in the cycle are lithium bromide-water in the absorption cycle and R134a in the vapour compression cycle. EES has been used to find out the results through doing simulation in it. The result of the simulation is to study the relationship between different components of the cycle such as generator, condenser, heat exchanger evaporator on the cop of the cycle. The outcome can be used to enhance the performance and determine the parameters for better working of the cascade cycle.

Comprehension of eruptive histories is critical in understanding the evolution of magmatic systems at arc volcanoes and may supply evidence to the petrogenesis of intermediate and evolved magmas. Within the 300 ka eruptive history of Mount St. Helens, Washington, the Kalama Eruptive Period, 1479- ~1750 CE was bracketed by interludes of quiescence (Hoblitt et al., 1980) and thus likely represents an entire eruptive cycle within a span of 300 years. Study of the magmatic evolution during this short time period provides key information regarding inputs and the plumbing system of Mount St. Helens. This research aims to enhance comprehension of processes leading to the petrogenesis of intermediate magmas by providing whole rock and phase geochemical data of an eruptive cycle, thereby providing constraints on the magmatic evolution of the Kalama Eruptive Period. The eruptive sequence is divided into early, middle and late subperiods. The early Kalama began with two dacitic plinian eruptions and continued with smaller eruptions of dacite domes (64.4-66.5 wt% SiO₂) that included quenched mafic inclusions (53.7-57.7 wt% SiO₂). The middle Kalama signified the onset of basaltic andesite and andesite eruptions ranging between 55.5-58.5 wt % SiO₂. Subsequently, summit domes that began as felsic andesite (61-62.5 wt% SiO₂) and transitioned to dacite (62.5-64.6 wt% SiO₂) dominated the late Kalama. Previous work on Kalama-aged rocks suggests magma mixing is an integral process in their production. Compositions and textures of crystal phases, in addition to the presence of xenocrysts in middle and late Kalama rocks, confirm mechanical mixing of magmas likely produced many of the sampled compositions. New petrographic observations were integrated with new whole rock and phase EMP and LA-ICP-MS data and the known stratigraphy in order to constrain the magmatic and crustal components active during the Kalama Eruptive Period. New findings include: 1. Two populations of quenched mafic inclusions, one olivine-rich and one olivine-poor, are identified from the early Kalama based on mineralogy, textures, and major and trace element chemistry. Major element modeling shows crustal anatexis of plutonic inclusions found in early Kalama dacites could produce the felsic magma source of the olivine-poor population. The olivine-rich population incorporated cumulate material. 2. Four distinct lava populations erupted during the early part of the middle Kalama (X lavas), including two found exclusively in lahar deposits: M-type lahars are the most mafic, B-type lahars are more mixed, the Two Finger Flow was previously grouped with other middle Kalama-age lavas, and the X lava (in situ) has unique geochemical and textural character. X tephras likely correlate with the lavas. 3. There were at least three mafic source contributions at Mount St. Helens during the eruptive period: the parent to the X deposits, the cumulate material in the olivine-rich QMIs, and the calc-alkaline parent to the MKLV and SDO. The magma reservoir at Mount St. Helens has been modeled as a single, elongate chamber (Pallister et al., 1992). Multiple coeval basaltic or basaltic andesite parents fluxing into the magmatic system beneath the volcano could indicate a more complex magma chamber structure.
Graduation date: 2011

The automobile industry is moving fast towards Electric Vehicles (EV); however this paradigm shift is currently making its smooth transition through the phase of Hybrid Electric Vehicles. There is an ever-growing need for integration of hybrid energy sources especially for vehicular applications. Different energy sources such as batteries, ultra-capacitors, fuel cells etc. are available. Usage of these varied energy sources alone or together in different combinations in automobiles requires advanced power electronic circuits and control methodologies. An exhaustive literature survey has been carried out to study the power electronic converter, switching modulation strategy to be employed and the particular machine to be used in an EV. Adequate amount of effort has been put into designing the vehicle specifications. Owing to stronger demand for higher performance and torque response in an EV, the Permanent Magnet Synchronous Machine has been favored over the traditional Induction Machine. The aim of this thesis is to demonstrate the use of a multi level inverter fed Brush Less Direct Current (BLDC) motor in a field oriented control fashion in an EV and make it follow a given drive cycle. The switching operation and control of a multi level inverter for specific power level and desired performance characteristics is investigated. The EV has been designed from scratch taking into consideration the various factors such as mass, coefficients of aerodynamic drag and air friction, tire radius etc. The design parameters are meant to meet the requirements of a commercial car. The various advantages of a multi level inverter fed PMSM have been demonstrated and an exhaustive performance evaluation has been done. The investigation is done by testing the designed system on a standard drive cycle, New York urban driving cycle. This highly transient driving cycle is particularly used because it provides rapidly changing acceleration and deceleration curves. Furthermore, the evaluation of the system under fault conditions is also done. It is demonstrated that the system is stable and has a ride-through capability under different fault conditions. The simulations have been carried out in MATLAB and Simulink, while some preliminary studies involving switching losses of the converter were done in PSIM.

Supercritical carbon dioxide (sCO2) power cycles have transitioned from the kilowatt level pilot facilities to the megawatt level demonstration plants. Theoretical studies and commercial benefits associated with sCO2, such as high efficiency, compact turbomachinery, fuel agnostic heat source, zero or minimum water usage, reduced footprint, cost, etc., have been comprehensively documented. Currently, with renewable energy gaining traction, the baseload steam and gas turbines are forced to operate as peak load plants with the need for increased operational flexibility. Therefore, the industrial power production segment (< 150 MW) is slowly gaining increasing attention worldwide, emphasizing the utilization of sCO2 technology. Waste Heat Recovery (WHR) is another important segment receiving wide attention as it contributes to energy efficiency in an increasingly climate-conscious world. Industrial WHR such as those from steel, cement, process plants, and gas turbine (GT) exhaust is equivalent to 63% of global primary energy consumption. sCO2 plays a significant role in WHR due to higher cycle efficiency, smaller footprint, and eventual lower capital cost than alternate waste heat to power conversion systems. A significant number of the sCO2 cycle studies and pilot plants have focused on low ambient conditions (32 °C compressor inlet) and higher turbine inlet temperature 'TIT' (>600 °C) for renewable energy applications. The ambient temperature influence is not trivial in real gas cycles such as sCO2. A greater focus is placed in previous studies on GT exhaust heat for sCO2 WHR and almost insignificant work in Industrial WHR. This thesis addresses the crucial gaps by proposing a Recompression cycle for renewable power generation and a Simple Recuperated cycle for WHR with higher ambient temperature (>40 °C) and TIT within 600 °C. Despite the reduction in thermal efficiency, limiting TIT has significant benefits. It enables leveraging cost-effective industrial steam turbine technology while still addressing large segments of renewable energy and industrial WHR. The second part of the thesis focuses on sCO2 turbomachinery development and testing, with emphasis on the sCO2 turbine. Kilowatt level pilot facilities have focused on radial turbines that are not scalable above 5 MW, where axial turbines are needed. Presently, there is very little published research on megawatt-scale axial sCO2 turbine due to their proprietary nature. Additionally, the focus on axial turbine development has been mainly for high-temperature applications requiring a range of new technologies and materials to be proven. The work presented in this thesis is among the initial publications to describe in detail the sCO2 axial turbine and blade development. Best in class sCO2 turbine blade profiles have been developed by employing novel optimization methods and Q3D, 3D solvers. This is followed by validation of blade performance in a linear cascade Wind Tunnel (WT) test at Politecnico di Milano, Italy. Subsequently, CFD-based 3D loss tuned using experimental data is utilized in the in-house developed mean-line code coupled to an industry-standard throughflow solver to generate the turbine flowpath. The last part of the thesis proposes a new analytical optimization model for sCO2 Brayton cycles utilizing Jacobian transformations and real gas thermodynamics. The analytical model has vital utility in transient dynamic analysis and real-time control of power and refrigeration cycles. In summary, the research comprehensively covers sCO2 cycles, turbomachinery development, and analysis by considering practical conditions, including comparisons with operating steam turbine power plants. The research culminates with case studies describing the development of sCO2 cycle and turbomachinery for a 10 MW renewable power generation and a 15 MW steel coke oven plant industrial WHR.

Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
Portugal enfrenta enormes desafios impostos por metas ambientais e pela atual situação económica e social da Europa. Neste contexto, a eco-edificação assume um papel importante no sector da construção. Apesar do recurso a materiais sustentáveis não ser novo, continua a existir uma enorme oportunidade tecnológica na otimização e caracterização de sistemas construtivos que potenciem o máximo benefício destes materiais. Por outro lado, há necessidade de verificar a capacidade de industrializar estas técnicas que, até ao momento, apresentam uma utilização pouco sistemática. Com este trabalho, pretendeu-se desenvolver uma solução de painel de parede inovadora (eco-painel), composta por madeira e palha ou casca de arroz, orientada para o mercado da eco-edificação. Previsivelmente, a utilização destes materiais possibilitará a definição de um produto sustentável, com impacte ambiental inferior ao de produtos concorrentes, e com propriedades de isolamento térmico e acústico adequadas. O estudo experimental foi conduzido nas instalações laboratoriais do ITeCons – Instituto de Investigação e Desenvolvimento Tecnológico em Ciências da Construção, recorrendo a um conjunto de equipamentos adequados à determinação da condutibilidade térmica e do índice de isolamento sonoro da solução construtiva. O eco-painel estudado foi também sujeito a uma avaliação de ciclo de vida. Os sistemas compostos por palha e casca de arroz foram comparados com os de soluções construtivas equivalentes constituídas por diferentes lãs de rocha, sendo os resultados obtidos indicadores de níveis de isolamento térmico e acústico adequados aos objetivos de aplicação. De salientar, ainda, que a solução construtiva estudada integra na sua estrutura subprodutos do setor agrícola, mais concretamente da região do Baixo Mondego, acrescentando assim um novo significado à ecoeficiência da solução proposta.
Portugal faces enormous challenges imposed by environmental goals and by the current economic and social situation that Europe is experiencing. In this context, the eco-edification assumes an important role in the construction sector. Although the use of sustainable materials isn’t new, still exists a huge technologic opportunity in the optimization and characterization of constructive systems that potentiates the maximum benefit of this materials. In the other hand, there is a need to verify the ability to industrialize these techniques which, until now, show a less systematic use. With this work, it was intended to develop an innovative solution of wall panel (eco-panel), composed by wood and rice straw or husk, oriented for the market of eco-edification. Predictably, the use of these materials will allow the definition of a sustainable product with an environmental impact lower than the concurrent products, and with appropriate thermic and acoustic properties. The experimental study was conducted in the laboratory facilities of ITeCons - Institute for Research and Technological Development in Construction Sciences, using a set of proper equipment for determining the thermal conductivity and sound isolation index of the constructive solution. The eco-panel study was also subject to an assessment of the life cycle. The systems composed of rice straw and rice husk systems were compared to those of an equivalent constructive solutions composed of different rock wool, and the results obtained were indicators of levels of thermal and acoustic isolation appropriate to the objectives of the application. To point, also, that constructive solution integrates in its structure sub products of the agricultural sector, more specifically of the region of “Baixo Mondego”, adding a new meaning to the eco-efficiency of the proposed solution