[pt] A preocupação com o esgotamento de recursos naturais, acrescida de legislações cada vez mais restritivas no descarte de materiais, fez com que modelos de negócio baseados na reutilização de itens ganhassem força em comparação aos baseados em descarte. Nas cadeias de distribuição do tipo closed-loop, a gestão de itens retornáveis permanece como ponto de grande preocupação para seus gestores, dados os altos investimentos realizados nestas populações, contrastando com a relativa baixa atenção dada ao desenvolvimento de técnicas de gestão. O controle individual de itens retornáveis com a utilização de tecnologias como identificação por radiofrequência (RFID) mostra-se como a solução para alguns destes desafios. O objetivo deste trabalho é avaliar a viabilidade desta aplicação dado o atual estágio de maturidade da tecnologia RFID, identificar os fatores críticos de sucesso através da análise de estudos de caso envolvendo aplicações similares, e propor uma abordagem integrada para a indústria de distribuição de gás liquefeito de petróleo (GLP) no mercado brasileiro. Tendo a tecnologia atingido um grau adequado de maturidade, com soluções integradas disponíveis no mercado, os principais desafios deste tipo de aplicação passam a envolver questões organizacionais, como a gestão da mudança, similarmente à implantação de tecnologias bastante maduras, como sistemas de gestão integrados. / [en] Concerns with the exhaustion of natural resources, combined with growing legal restrictions on waste disposal, has drawn attention to business models based on the reutilization of items, in comparison with the disposal-based models. In closed-loop supply chains, the management of returnable items remains as a major challenge for its leaders, due to the significant investments made on these populations, contrasting with the relatively low attention given to the development of management practices in this area. The individual control of returnable items with the use of the radio frequency identification (RFID) technology emerges as a possible solution for these challenges. The objectives of this research are to evaluate the current maturity level of the RFID technology, identify critical success factors through the analysis of related case studies, and propose an integrated approach for the liquefied petroleum gas (LPG) distribution industry in Brazil. Having reached a satisfactory maturity level, with integrated solutions available in the marketplace, the main challenges of such applications move towards organizational issues, as change management, similar to the implementation of more mature technologies, such as enterprise resource planning systems.

This thesis deals with the construction proposal of the combustion chamber of Stirling engine. The introduction briefly describes the history and practical application of Stirlinova engine today. The following section explains the differences between theoretical and real cycle and the principle of beta Stirling engine modifications. The next section is devoted to the calculation of fuel and air consumption and fuel compared to each other. The proposed design is based not only on the calculation of fuel and air, but also heat transfer between flue gas and preheated air. The last part is devoted to calculating the flow of LPG and flow model of the combustion chamber.

Mit der Dissertation wird eine Periodisierung der Landwirtschaft der SBZ/DDR von 1945 bis 1990 vorgestellt und der LPG-Entwicklung speziell von 1960 bis 1969 vorgenommen. Dabei werden Etappen und Phasen abhängig von Zäsuren unterschieden. Es wird der Weg der drei LPG-Typen von der anfangs z. T. noch großbäuerlichen Wirtschaftsweise bis zur „sozialistischen Kooperation“ aufgezeigt. Dabei kam es zu Formen der Konzentration und Spezialisierung der Produktion. In der Dissertation wird auf sächsische Besonderheiten und Abweichungen von der Staatspolitik eingegangen. Bei der Darstellung der Ergebnisse der LPG werden Vergleiche zwischen den sächsischen Bezirken und der DDR gezogen. Die Arbeit enthält umfangreiche Ausführungen zu den beiden Wegen zur Betriebsvergrößerung der LPG. Als wichtig wurde angesehen, die Entwicklung aller drei LPG-Typen herauszuarbeiten. Die LPG als „sozialistische“ Genossenschaften werden als nicht identisch mit dem deutschen Genossenschaftsgesetz und auf dem „Leninschen Genossenschaftsplan“ fußend charakterisiert. Die Arbeit geht auf „sozialistische Experimente“ in der Agrarpolitik der DDR ein. Der Untersuchungszeitraum für das LPG-Modell in Sachsen fällt mit dem Ergebnis der gescheiterten Wirtschaftsreform der DDR, des NÖSPL, zusammen. Das LPG-Modell, auch in den sächsischen Bezirken, zwischen 1960 und 1970 war der westdeutschen Landwirtschaft hinsichtlich der Versorgungssicherheit nicht überlegen.

En vue d’éviter ou de diminuer l’importance des dégâts causés par les accidents majeurs, il convient de modéliser les fonctions et les relations entre les composants d’un système industriel. Pour cela, dans cette thèse, on utilise la démarche de modélisation par la méthode STAMP (Systems-Theoretic Accident Model and Processes) pour représenter la structure hiéarchique du système, ainsi que les mécanismes de contrôle nécessaire pour préserver la sécurité d’un processus industriel. Afin de traiter les problématiques liées aux contrôles de la sécurité industrielle, on propose l’utilisation de l’outil de simulation Anylogic. Cet outil, permet modéliser et de simuler le comportement du système en fonction du temps en mode normal et en mode dégradé.L’objectif de ces travaux est donc de proposer une démarche basée à la fois sur la modélisation et la simulation pour analyser les risques et prévenir les accidents d’un site de stockage et distribution de GPL (Gaz Pétrole liquéfié). / System thinking concepts and simulation tools are used to model the risk prevention plan and operational modes designed to enforce safety constraints at a French liquefied petroleum gas (LPG) storage and distribution facility. In France, such facilities are classified and the subject of special legislation and safety regulations. Their supervision is the responsibility of a control and regulatory body. A technological risk and prevention plan is provided, where all the dangerous phenomena likely to occur in addition to the safety control measures are listed in the safety report. Safety is therefore addressed through rules, and control mechanisms ensure that the system complies with safety constraints. Taking this facility as a case study, we use the STAMP theoretical framework together with AnyLogic simulation software to model technical elements and human and organizational behavior. We simulate how the system evolves over time and the strategies that are deployed in a loss of control scenario. The aim is to assess whether the prescribed safety program covers all of the system's phases; namely operations and audits. The results enrich other research that focuses on the contribution of system dynamics to risk analysis and accident prevention.

Este trabalho apresenta o estudo, a implementação e a caracterização de transdutores compostos por uma estrutura formada por grades de Bragg (FBG, Fiber Bragg Gratings) e grades de período longo (LPG, Long Period Gratings) em fibra óptica com cobertura metálica autoaquecida para medição da condutividade térmica e da difusividade térmica de materiais baseado no método do fio quente (HWM, Hot-Wire Method) convencional. O autoaquecimento da fibra óptica do dispositivo desenvolvido neste trabalho é provocado pela luz de espectro infravermelho injetada por um laser de bombeamento, que é espalhada por uma LPG e absorvida por um filme fino metálico depositado na superfície da fibra. Os transdutores apresentados são compactos, simples, robustos e imunes a interferências eletromagnéticas. O arranjo experimental utilizando o dispositivo híbrido LPG-FBG foi capaz de medir as condutividades térmicas do ar atmosférico e da água comum com precisões de 27% e 14%, respectivamente. Foram identificados vários fatores que afetam a precisão e a exatidão das medidas realizadas, sendo propostas diversas formas de correções de modo a melhorar o desempenho do arranjo. Foi demonstrada com sucesso a viabilidade da aplicação original do arranjo experimental utilizando o dispositivo híbrido LPG-FBG em fibra óptica autoaquecida para a medição de propriedades térmicas de fluidos (ar e água). / This work presents the study, implementation, and characterization of transducers composed of a structure formed by Fiber Bragg Gratings (FBG) and Long Period Gratings (LPG) in optical fiber with self-heating coverage for measurement of thermal conductivity and thermal diffusivity of materials based on the Hot-Wire Method (HWM). The self-heating fiber optic device developed in this work is caused by the light of infrared spectrum injected by a pumping laser, which is spread by an LPG and absorbed by a thin metallic film deposited on the surface of the fiber. The transducers are compact, simple, robust and immune to electromagnetic interference. The experimental arrangement using the optical fiber sensor based on LPG-FBG hybrid structure was able to measure the thermal conductivity of atmospheric air and water with accuracies of 27% and 14%, respectively. Several factors were identified that affect the precision and the accuracy of the measures carried out, whereby various forms of corrections are being proposed to improve overall performance. The viability of the original application of the experimental arrangement using the LPG-FBG hybrid device in self-heating optical fiber for the measurement of thermal properties of fluids (air and water) has been successfully demonstrated.

No panorama energético brasileiro, a geração de água quente e fria, pelos métodos convencionais, utilizando energia elétrica, implica em mais um fator de sobrecarga no sistema de geração, transporte e distribuição, potencializando os conhecidos picos de energia, onde o sistema de geração de energia elétrica de nosso país tem que estar dimensionado por apenas seis horas por dia e que para continuar garantindo esta energia exige pesados investimentos públicos, com grandes impactos. A energia elétrica é uma forma de energia de alta qualidade, devendo assim ser destinada a aplicações nobres, onde não é possível substituí-la. Maior importância tem sido dada ao estudo dos sistemas de refrigeração por absorção, devido às peculiaridades desses sistemas em relação aos ciclos por compressão e também pelo aproveitamento dos rejeitos térmicos. O objetivo desta pesquisa é contribuir para a redução do consumo de energia elétrica no setor comercial, mais especificadamente em hotelaria, situação esta que encontramos no consumo simultâneo de fonte de calor quente e fria. No entanto como fonte de energia alternativa a energia elétrica busca-se o gás LP, devido a sua capilaridade de distribuição de grande acesso aos empreendimentos em qualquer local do país e alto poder calorífico. O sistema de ar condicionado a gás LP é uma opção para sistemas de climatização. Proporciona uma significativa redução de consumo de energia quando se busca um equilíbrio nas demandas de fonte quente e fria / The Brazilian energy landscape, the generation of hot and cold water, by conventional methods, using electricity, implies an additional overhead factor in system generation, transmission and distribution, leveraging the familiar \"power surges\", where the system electric power generation in our country have to be sized for only six hours a day and to continue ensuring that energy demands heavy public investment, with major impacts. Electricity is a form of high quality power and should therefore be applicable for nobles, where you cannot replace it. Greater importance has been given to the study of the absorption refrigeration systems, due to the peculiarities of these systems in relation to the cycles of compression and also the utilization of waste heat. The objective of this research is to contribute to reducing electricity consumption in the commercial sector, more specifically in hotels, we found this situation in simultaneous consumption of heat source hot and cold. However as an alternative energy source to power up the search LPG, due to its capillary distribution of large enterprises access to anywhere in the country and high calorific value. The air conditioning system LPG is an option for air conditioning systems. Provides a significant reduction of energy consumption when it seeks to balance the demands of hot and cold source.

No panorama energético brasileiro, a geração de água quente e fria, pelos métodos convencionais, utilizando energia elétrica, implica em mais um fator de sobrecarga no sistema de geração, transporte e distribuição, potencializando os conhecidos picos de energia, onde o sistema de geração de energia elétrica de nosso país tem que estar dimensionado por apenas seis horas por dia e que para continuar garantindo esta energia exige pesados investimentos públicos, com grandes impactos. A energia elétrica é uma forma de energia de alta qualidade, devendo assim ser destinada a aplicações nobres, onde não é possível substituí-la. Maior importância tem sido dada ao estudo dos sistemas de refrigeração por absorção, devido às peculiaridades desses sistemas em relação aos ciclos por compressão e também pelo aproveitamento dos rejeitos térmicos. O objetivo desta pesquisa é contribuir para a redução do consumo de energia elétrica no setor comercial, mais especificadamente em hotelaria, situação esta que encontramos no consumo simultâneo de fonte de calor quente e fria. No entanto como fonte de energia alternativa a energia elétrica busca-se o gás LP, devido a sua capilaridade de distribuição de grande acesso aos empreendimentos em qualquer local do país e alto poder calorífico. O sistema de ar condicionado a gás LP é uma opção para sistemas de climatização. Proporciona uma significativa redução de consumo de energia quando se busca um equilíbrio nas demandas de fonte quente e fria / The Brazilian energy landscape, the generation of hot and cold water, by conventional methods, using electricity, implies an additional overhead factor in system generation, transmission and distribution, leveraging the familiar \"power surges\", where the system electric power generation in our country have to be sized for only six hours a day and to continue ensuring that energy demands heavy public investment, with major impacts. Electricity is a form of high quality power and should therefore be applicable for nobles, where you cannot replace it. Greater importance has been given to the study of the absorption refrigeration systems, due to the peculiarities of these systems in relation to the cycles of compression and also the utilization of waste heat. The objective of this research is to contribute to reducing electricity consumption in the commercial sector, more specifically in hotels, we found this situation in simultaneous consumption of heat source hot and cold. However as an alternative energy source to power up the search LPG, due to its capillary distribution of large enterprises access to anywhere in the country and high calorific value. The air conditioning system LPG is an option for air conditioning systems. Provides a significant reduction of energy consumption when it seeks to balance the demands of hot and cold source.

Este trabalho apresenta o estudo, a implementação e a caracterização de transdutores compostos por uma estrutura formada por grades de Bragg (FBG, Fiber Bragg Gratings) e grades de período longo (LPG, Long Period Gratings) em fibra óptica com cobertura metálica autoaquecida para medição da condutividade térmica e da difusividade térmica de materiais baseado no método do fio quente (HWM, Hot-Wire Method) convencional. O autoaquecimento da fibra óptica do dispositivo desenvolvido neste trabalho é provocado pela luz de espectro infravermelho injetada por um laser de bombeamento, que é espalhada por uma LPG e absorvida por um filme fino metálico depositado na superfície da fibra. Os transdutores apresentados são compactos, simples, robustos e imunes a interferências eletromagnéticas. O arranjo experimental utilizando o dispositivo híbrido LPG-FBG foi capaz de medir as condutividades térmicas do ar atmosférico e da água comum com precisões de 27% e 14%, respectivamente. Foram identificados vários fatores que afetam a precisão e a exatidão das medidas realizadas, sendo propostas diversas formas de correções de modo a melhorar o desempenho do arranjo. Foi demonstrada com sucesso a viabilidade da aplicação original do arranjo experimental utilizando o dispositivo híbrido LPG-FBG em fibra óptica autoaquecida para a medição de propriedades térmicas de fluidos (ar e água). / This work presents the study, implementation, and characterization of transducers composed of a structure formed by Fiber Bragg Gratings (FBG) and Long Period Gratings (LPG) in optical fiber with self-heating coverage for measurement of thermal conductivity and thermal diffusivity of materials based on the Hot-Wire Method (HWM). The self-heating fiber optic device developed in this work is caused by the light of infrared spectrum injected by a pumping laser, which is spread by an LPG and absorbed by a thin metallic film deposited on the surface of the fiber. The transducers are compact, simple, robust and immune to electromagnetic interference. The experimental arrangement using the optical fiber sensor based on LPG-FBG hybrid structure was able to measure the thermal conductivity of atmospheric air and water with accuracies of 27% and 14%, respectively. Several factors were identified that affect the precision and the accuracy of the measures carried out, whereby various forms of corrections are being proposed to improve overall performance. The viability of the original application of the experimental arrangement using the LPG-FBG hybrid device in self-heating optical fiber for the measurement of thermal properties of fluids (air and water) has been successfully demonstrated.

Modern society has become reliant on battery powered electronic devices such as cell phones and laptop computers. The standard way of recharging these devices is by connecting to a reticulated electricity supply. In situations with no electricity supply some other recharging method is required. Such a possibility is a small, portable, generator based on fuel cell technology, specifically mini-tubular solid oxide fuel cells (MT-SOFC). MT-SOFCs have been developed since the 1990s but there is limited analysis, discussion or research on developing and constructing a portable generator based on MT-SOFC technology. Such a generator, running on a portable gas supply, requires combining the key aspects of cell performance, a heating and fuel reforming system, and cell manifolds. Cell design, fuel type, fuel flow rate, current-collection method and operating temperature all greatly affected MT-SOFCs performance. Segmenting the cathode significantly increased the power output. Maximum power density from an electrolyte supported MT-SOFC was 140 mW/cm2. The partial oxidation reactor (POR) developed provided the required heat to maintain the MT-SOFCs at an operating temperature suitable for generating electricity. The exhaust gas from the POR was a suitable fuel for MT-SOFCs, having sufficient carbon monoxide and hydrogen to generate electricity. Various manifold materials were evaluated including solid metal blocks and folded sheet metal. It was found that manifolds made from easily worked alumina fibre board decreased the thermal stresses and therefore the fracture rate of the MT-SOFCs. The final prototype developed comprised a partial oxidation reactor and MT-SOFCs mounted in alumina fibre board manifolds within a well-insulated enclosure, which could be run on LPG. Calculated efficiency of the final prototype was 4%. If all the carbon monoxide and hydrogen produced by the partial oxidation reactor were converted to electrical energy, efficiency would increase to 39%. Under ideal conditions, efficiency would be 78%. Efficiency of the prototype can be improved by increasing the fuel and oxygen utilisation ratios, ensuring heat from the exhaust gases is transferred to the incoming gases, and improving the methods for collecting current at both the anode and cathode.

[Les capteurs à fibres optiques présentent des qualités intéressantes en termes de tailles et de poids relativement faibles qui permettent de réduire l'intrusivité du capteur dans le matériau (ou dans la structure composite). Ils sont également insensibles aux perturbations électromagnétiques, stables et durables dans le temps, mais aussi sensibles à plusieurs sollicitations comme la température, la déformation et la pression, d'où un besoin essentiel de les discriminer. Parmi eux on distingue les réseaux de Bragg : ceux à courtes périodes (FBG : Fiber Bragg Grating) et ceux à longues périodes (LPG : Long Period Grating). Le travail de thèse reporté dans ce manuscrit, traite du développement d'un capteur à fibre optique basé sur la superposition d'un LPG et d'un FBG afin de mesurer et de discriminer la température et la déformation. De nombreuses approches sont proposées dans la littérature afin de découpler ces deux sollicitations cependant elles ne permettent pas forcément une utilisation en conditions réelles de mesures. C'est pourquoi nous introduisons la notion d'efficacité de découplage avec le paramètre E qui permet de comparer toutes ces approches et met en évidence un très bon potentiel pour la structure à base de réseaux superposés LPG/FBG. La mise en œuvre d'un tel composant est décrite dans ce manuscrit et consiste à inscrire initialement le LPG puis le FBG au même endroit et sur toute la longueur du LPG. De plus ce type de structure permet un multiplexage qui, bien que faible, est néanmoins possible. Les étalonnages en température et en déformation du capteur ont permis de mettre en évidence une erreur de l'ordre de 2% sur la sensibilité à la température et de 3% sur la sensibilité à la déformation, ce qui conduit à une erreur sur l'estimation de la température et de la déformation mesurée de l'ordre de 0.3°C et 3 microdef. Dans un souci applicatif, le capteur à base de réseaux de Bragg superposés est tout d'abord utilisé pour instrumenter une structure métallique soumise simultanément à une variation de température et de déformation. Les valeurs mesurées présentent une incertitude maximale de 0.4°C pour la température et de 3 me pour la déformation ce qui permet de valider notre composant pour le contrôle et la surveillance de structures métalliques. La seconde application étudiée est relative à l'instrumentation de pièces composites stratifiées de type verre/époxy pour le suivi de procédés d'élaboration par voie liquide : VARTM (Vacuum Assisted Resin Transfer Molding) et LRI (Liquid Resin Infusion), pour lesquels l'évolution de la température et de la déformation au cours du procédé est suivie par le capteur à base de réseaux de Bragg superposés LPG/FBG. Des mesures diélectriques (DEA) sont également réalisées au cours de ces procédés et permettent la comparaison et la validation de nos résultats]