This study investigates the manifestation of geometric features of turbine blades in signatures of non-optical time of arrival (ToA) probes. The approach enables an evaluation of the various signal characteristics used for defining ToA for a range of airfoil geometries and provides knowledge about additional waveform characteristics. The objective of this research is to increase the accuracy of microwave ToA probes by gaining a better understanding of the microwave signals in five steps. Firstly, ToA definitions used in the past are compared. Considering accuracy, computational effort, and versatility, the constant fraction crossing definition is found to be the most accurate. Secondly, an experimental apparatus capable of measuring airfoil ToA with microwave probes and optical probes as a reference is designed and built. As a third step, a catalog of 16 turbine blade geometries is developed. Fourthly, the signatures of these turbine blades are acquired using both the optical and the microwave probes. Finally, the impact of the geometric effects on the signatures is evaluated. The quality of the microwave results is found to be highly dependent on the polarization of the microwaves. Analysis of the time domain signal shows that decreasing the blade width, increasing the chord angle, or incorporating a blade tip pocket or a varying cross-section leads to a decrease in the amplitude of the peak caused by the blade. Increasing the blade width and incorporating a chord angle leads to an increase in peak width. A frequency domain analysis is conducted on the microwave signals and verified using a synthetic signal. This analysis confirms the findings from the time domain analysis. The time domain analysis of the laser measurements shows that the spatial resolution of the laser is much higher than that of the microwave sensor. Consequently, the signal acquired with the optical setup provides a good means of defining the blade ToA. The knowledge gained in this study about the sensor and its interaction with passing blade tips of varying geometry can be used to enhance the understanding of microwave ToA measurements. This knowledge provides further insight into airfoil and engine health.

Thesis (Ph.D.)--Aerospace Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dr. Vitali Volovoi; Committee Co-Chair: Dr. Massimo Ruzzene; Committee Member: Dr. Andrew Makeev; Committee Member: Dr. Dewey Hodges; Committee Member: Dr. Peter Cento

Nos recherches se sont orientées vers l'étude des niveaux correspondant aux dernières phases du Moustérien de deux sites en grotte, Grotta del Cavallo et Grotta Mario Bernadini, situées sur le versant ionique des Pouilles dans la province de Lecce . Les deux sites en question ont fait l'objet de nombreuses études à partir des années 1960 (Palma Di Cesnola, 1963 ; Borzatti, 1970). Le choix de se concentrer spécifiquement sur les phases finales de cette période a été d'abord motivée par la nécessité de combler un vide de connaissance dans l'aire prise en compte concernant les aspects technologiques. L'objectif premier a été par conséquence de reconstituer les éléments liés à la production afin d'en comprendre la spécificité technologique et, dans une certaine mesure, les comportements techno-économiques. Ensuite, le choix des collections s'inscrit dans la volonté d'établir le point de départ pour évaluer à travers une confrontation entre les séries, les rapports phylogénétiques entre les dernières phases du Moustérien et les industries uluzziennes qui dans les deux sites succèdent à la séquence moustérienne. Enfin, le choix des deux sites repose sur une raison d'ordre géographique. Si les Pouilles constituent déjà un contexte particulier lié à l'isolement de l'extrême sud-est de l'Italie, la région de Salento qui est située dans sa partie méridionale se présente comme une insularité dans l'insularité. Cette position géographique singulière pourrait avoir revêtu un rôle d'isolement potentiel par rapport aux autres régions limitrophes et avoir comme conséquence laconstitution de phénomène locaux qui se sont traduit dans l'expression de caractères culturels, au sens plus large du terme, originaux. / The puzzles arising from the fragmentation of the Mousterian expressions in their late phases, as emerged fromthe archaeological evidence, have always been of interest for prehistoric research, as far as they are concerned with both cultural and biological aspects of human evolution. The cultural complexity that can be observed between 40.000 and 28.000 years ago in Europe depends onthe variety of Neanderthal economic and symbolic attitudes, in relation to both the advent of new technical expressions (Castelperronian, Uluzzian and sensu lato, transitional complexes) and to the persistente of productions that are still rooted in to the traditional variability of theMousterian groups. At the same time the appearing of techno-complexes attributed to the Upper Palaeolithic has been related by some authors to the emergence of particolar cognitive abilities, ascribed to the arrival of the anatomically modern humans (AMH) in Europe. In the last years the recognition of blades and bladelets productions in Mousterian context in France, Italy and in the Near East has mitigated this hypothetical relationship between these productionsand the spread of the AMH. This paper reports the results of the study of Mousterian lithic industries of Grotta del Cavallo and Grotta Mario Bernardini (Nardò, Lecce). The technological study shows the development of an autonomous schèma opératoire (along with other types of productions) oriented in the direction of blades and bladelets production bymeans of a volumetric exploitation. The recognition of this type of production - not recorded until now in the Salentin area - gives us the possibility to review the production systems that we can attribute at the Mousterian terminal phases of the southern Italy.

Este trabalho buscou analisar dois materiais para fabricação de navalhas para corte de sucata, de forma a identificar aquele que melhor atenda às solicitações de desgaste dentro de um custo competitivo. Foram realizados testes comparativos de desempenho entre navalhas de aço AISI S1 e SAE 4340, sendo este último o material base utilizado atualmente para a fabricação de navalhas para corte de sucata na Gerdau Aços Especiais Charqueadas. O estudo foi realizado durante o processamento de sucata em uma Prensa Tesoura Harris BSH 1123, sendo que as medições de desgaste foram realizadas nas arestas de corte com a utilização de um relógio comparador. Os resultados mostram que o aço ferramenta, apesar de seu elevado custo e necessidade de maior controle durante o tratamento térmico, é superior em todos os aspectos, apresentando a metade do desgaste do aço ligado quando utilizado nas mesmas condições e trazendo benefícios operacionais como a redução do tempo de troca das navalhas, sendo o material mais indicado para este fim. / Performance trials were carried out to identify the most suitable material for the manufacturing of blades for scrap cutting considering resistance for wear specifications as well as competitive cost. The materials tested were AISI S1 and SAE 4340, being the latter the material currently used for this application at Gerdau Aços Especiais Charqueadas. The study was conducted during scrap processing in a Harris BSH 1123 shearing press. In order to measure the cutting edge wear, a dial gauge was employed. The results show that the tool steel, despite its higher cost and more complex heat treatment process, is superior for all analyzed aspects, presenting less than half of the wear shown by the low alloyed steel when processing scrap under the same conditions. Other additional operational benefits also were obtained as a decrease in the set up time, being the material of choice for this task.

Wind energy, one of the most promising sources of clean energy, has developed rapidly over the last two decades. Wind turbines (WT) are arguably clean during operation, offering minimal pollution and zero CO2 emissions, but significant amounts of energy are used and CO2 emitted during their manufacture, and, furthermore, the turbines are environmentally problematic at end-of-life (EoL), especially the blades. WT blades are mainly made with composite materials comprising thermosetting resin and glass fibre. They are lightweight and strong but problematic to recycle. Large volumes of waste will be generated when these WT blades are decommissioned and environmental concerns have been raised. The main aim of this study is to understand the environmental impact of wind turbine blades and to find solutions to reduce it. A quantitative method is adopted, first evaluating the WT blade waste inventory then calculating its environmental impact, and finally analysing the differences between all possible EoL options in terms of environmental and financial performance. The results firstly identify the global wind turbine blade waste inventory with detailed generation time and location which could help policy makers to gain an understanding of the size and severity of this problem. Secondly, the outputs indicate where most impact is generated and identify what to prioritise to reduce waste and reduce environmental impact, which is of value to blade manufacturers and other stakeholders. Moreover, this work highlights previous incorrect assumptions and provides findings to build on for future work. Thirdly, ‘optimal’ EoL options for the WT blade waste have been characterized: the current ‘optimal’ EoL option is life extension; mechanical recycling is the current ‘optimal’ recycling option; chemical recycling will be the ‘optimal’ option for the future. Future research is suggested as aiming to improve the performance of recycled fibre or to reduce the energy consumption of recycling processes.

Este trabalho buscou analisar dois materiais para fabricação de navalhas para corte de sucata, de forma a identificar aquele que melhor atenda às solicitações de desgaste dentro de um custo competitivo. Foram realizados testes comparativos de desempenho entre navalhas de aço AISI S1 e SAE 4340, sendo este último o material base utilizado atualmente para a fabricação de navalhas para corte de sucata na Gerdau Aços Especiais Charqueadas. O estudo foi realizado durante o processamento de sucata em uma Prensa Tesoura Harris BSH 1123, sendo que as medições de desgaste foram realizadas nas arestas de corte com a utilização de um relógio comparador. Os resultados mostram que o aço ferramenta, apesar de seu elevado custo e necessidade de maior controle durante o tratamento térmico, é superior em todos os aspectos, apresentando a metade do desgaste do aço ligado quando utilizado nas mesmas condições e trazendo benefícios operacionais como a redução do tempo de troca das navalhas, sendo o material mais indicado para este fim. / Performance trials were carried out to identify the most suitable material for the manufacturing of blades for scrap cutting considering resistance for wear specifications as well as competitive cost. The materials tested were AISI S1 and SAE 4340, being the latter the material currently used for this application at Gerdau Aços Especiais Charqueadas. The study was conducted during scrap processing in a Harris BSH 1123 shearing press. In order to measure the cutting edge wear, a dial gauge was employed. The results show that the tool steel, despite its higher cost and more complex heat treatment process, is superior for all analyzed aspects, presenting less than half of the wear shown by the low alloyed steel when processing scrap under the same conditions. Other additional operational benefits also were obtained as a decrease in the set up time, being the material of choice for this task.

Submitted by PAULO SILAS OLIVEIRA (paulo_pso@hotmail.com) on 2017-09-21T18:32:52Z No. of bitstreams: 1 DISSERTAÇÃO PSO.pdf: 2528233 bytes, checksum: 9afc1a3039409fe2145077515d301f3d (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-09-26T13:50:38Z (GMT) No. of bitstreams: 1 oliveira_ps_me_soro.pdf: 2563476 bytes, checksum: 6fbd8ead3546cb380f44253aa8dd8ac3 (MD5) / Made available in DSpace on 2017-09-26T13:50:38Z (GMT). No. of bitstreams: 1 oliveira_ps_me_soro.pdf: 2563476 bytes, checksum: 6fbd8ead3546cb380f44253aa8dd8ac3 (MD5) Previous issue date: 2017-09-20 / Dentre as diversas maneiras de se obter energia limpa, a energia eólica é o setor que esta em grande expansão, pois apresentou no Brasil, em 2015 um crescimento de 77,1% em comparação ao ano de 2014. Este crescimento acelerado traz juntamente uma enorme quantidade de resíduos gerados no processo de fabricação dos conjuntos geradores de energia. Um dos componentes dos conjuntos geradores é a pá eólica, confeccionada basicamente de uma estrutura, envolta por resina epóxi, fibra de vidro, madeira e cola. Uma empresa localizada na cidade de Sorocaba, fabricante de pás eólicas, têm capacidade de produção de 200 pás/mês que gera uma quantidade considerável de resíduos. Este trabalho visa incorporar a resina epóxi misturada com fibra de vidro, que é um resíduo gerado na produção das pás eólicas, em argamassa fabricada com cimento Portland CPII F32, com o objetivo de utilizar o resíduo substituindo parcialmente a areia empregada, pois desta forma há possibilidade de redução do descarte em aterros, e também diminuição da utilização de recursos naturais. Inicialmente o resíduo coletado na forma sólida, foi transformado em pó através do processo de torneamento, este pó foi caracterizado pelas técnicas de ângulo de contato, massa específica, teor de inorgânicos, granulometria, Difração de Raios X (DRX), Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Raios X por Dispersão em Energia (EDS). Posterior às caracterizações, foram confeccionados corpos de prova cimentícios com diversas proporções de substituição da areia pelo resíduo, além de um corpo de prova (CP) sem adição. Seguido da confecção dos CP foram realizados ensaios de tração na flexão, compressão, absorção de água, índice de vazios, microscopia ótica e massa específica das argamassas. Os resultados atestaram aprovação nos critérios de resistência mecânica (8 MPa), quando o resíduo substitui até 15% da areia, além de apresentar redução de massa específica, sendo vantajosa a aplicação na construção civil. / Among the various ways to obtain clean energy, wind power has been growing rapidly. In Brazil, the use of wind power grew 77.1% in 2015 compared with the previous year. This growth results in an enormous additional amount of residue produced during the manufacture of wind power generators. Wind turbine blades, which play an important role in the whole system, are made of a structure covered with epoxy resin, fiberglass, wood and glue. A company that manufactures wind power generators located in Sorocaba can produce up to 200 wind blades per month, which produces a considerable amount of residue. This project aims to incorporate epoxy resin together with fiberglass, which is also used in the production of such blades, into mortar made with Portland CPII F32 cement; that is to substitute residue for part of the sand used in this process, so that the quantity of residue (waste) can be reduced, and consequently also reduce the use of natural resources. Initially, this residue was collected in its solid form, and then turned into powder using the turning process for milling. This powder was characterized by contact angle and specific mass measurements, determination of inorganic elements, granulometry, X-ray diffraction, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). After the characterizations, some cement specimens were made with different quantities of residue substituting the sand, as well as a specimen (CP) without any substitution. Tests were then carried out, including resistance to bending traction and compression; determination of water absorption, void indices and of specific mass. The specimens showed positive results, having passed the mechanical resistance test (8MPa), when residue substituted up to 15% of the sand was substituted. In addition, the tests showed that the specific mass was also reduced, making it advantageous in applications in Civil Engineering.

O uso de materiais inteligentes em problemas de controle de vibração tem sido investigado em diversas pesquisas ao longo dos últimos anos. Apesar de que diferentes materiais inteligentes estão disponíveis, o piezelétrico tem recebido grande atenção devido à facilidade de uso como sensores, atuadores, ou ambos simultaneamente. As principais técnicas de controle usando materiais piezoelétricos são os ativos e passivos. Circuitos piezelétricos passivos são ajustados para uma frequência específica e, portanto, a largura de banda efetiva é pequena. Embora os sistemas ativos possam apresentar um bom desempenho no controle de vibração, a quantidade de energia externa e hardware adicionado são questões importantes. As técnicas SSD (Synchronized Switch Damping) foram desenvolvidas como uma alternativa aos controladores passivos e controladores ativos de vibração. Elas podem ser técnicas semi-ativas ou semi-passivas que introduzem um tratamento não linear na tensão elétrica proveniente do material piezelétrico e induz um aumento na conversão de energia mecânica para energia elétrica e, consequentemente, um aumento no efeito de amortecimento. Neste trabalho, o controle piezoelétrico semi-passivo de uma pá piezelétrica engastada é apresentado e comparado com outros controladores. O modelo não linear electromecânico de uma pá com piezocerâmicas incorporados é determinado com base no método variacional-assintótico (VAM). O sistema rotativo acoplado não linear é resolvido no domínio do tempo, utilizando um método de integração alfa-generalizado afim de garantir a estabilidade numérica. As simulações são realizadas para uma vasta gama de velocidades de rotação. Em primeiro lugar, um conjunto de resistências (variando desde a condição de curto-circuito para a condição de circuito aberto) é considerada. O efeito da resistência ótima (que resulta em máximo amortecimento) sobre o comportamento do sistema é investigado para o aumento da velocidade de rotação. Mais tarde, a técnica SSDS é utilizada para amortecer as oscilações da pá com o aumento da velocidade de rotação. Os resultados mostram que a técnica SSDS pode ser um método útil para o controle de vibrações de vigas rotativas não lineares, tais como pás de helicóptero. / The use of smart materials in vibration control problems has been investigated in several researches over the last years. Although dierent smart materials are available, the piezoelectric one has received great attention due to ease of use as sensors, actuators, or both. The main control techniques using piezoelectric materials are the active and passive ones. Passive piezoelectric networks are adjusted for specic target frequencies and, therefore, the eective bandwidth of such systems is small. Although active systems can achieve good vibration control performance, the amount of external power and added hardware are important issues. The synchronized switch damping (SSD) technique was developed in order to address the issues of passive damping methodologies as well as the issues of active control systems. The SSD can be classied as semi-passive technique or semi-active technique that introduce the nonlinear treatment of the piezoelectric element voltage output and induce an increase in mechanical to electrical energy conversion and, consequently, the shunt damping eect. In this work, the semi-passive piezoelectric control of a rotating cantilever beam response is presented and compared with other controllers. The nonlinear electromechanical model of a rotating beam with embedded piezoceramics is derived based on the variational-asymptotic method (VAM). The coupled non-linear rotary system is solved in the time-domain by using a generalized-alpha integration method in order to guarantee numerical stability. The simulations are performed for a wide range of rotating speeds. First, a set of load resistances (ranging from short circuit condition to open circuit condition) is considered. The eect of optimum load resistance (for maximum damping) on the elastic behavior of the beam is investigated for increasing rotating speed. Later, the synchronized switch damping on short (SSDS) technique is employed to damp the nonlinear oscillations of the rotating beam with increasing rotating speed. Results show that the SSDS technique can be a useful method of control for nonlinear rotating beams such as helicopter blades.

Este trabalho buscou analisar dois materiais para fabricação de navalhas para corte de sucata, de forma a identificar aquele que melhor atenda às solicitações de desgaste dentro de um custo competitivo. Foram realizados testes comparativos de desempenho entre navalhas de aço AISI S1 e SAE 4340, sendo este último o material base utilizado atualmente para a fabricação de navalhas para corte de sucata na Gerdau Aços Especiais Charqueadas. O estudo foi realizado durante o processamento de sucata em uma Prensa Tesoura Harris BSH 1123, sendo que as medições de desgaste foram realizadas nas arestas de corte com a utilização de um relógio comparador. Os resultados mostram que o aço ferramenta, apesar de seu elevado custo e necessidade de maior controle durante o tratamento térmico, é superior em todos os aspectos, apresentando a metade do desgaste do aço ligado quando utilizado nas mesmas condições e trazendo benefícios operacionais como a redução do tempo de troca das navalhas, sendo o material mais indicado para este fim. / Performance trials were carried out to identify the most suitable material for the manufacturing of blades for scrap cutting considering resistance for wear specifications as well as competitive cost. The materials tested were AISI S1 and SAE 4340, being the latter the material currently used for this application at Gerdau Aços Especiais Charqueadas. The study was conducted during scrap processing in a Harris BSH 1123 shearing press. In order to measure the cutting edge wear, a dial gauge was employed. The results show that the tool steel, despite its higher cost and more complex heat treatment process, is superior for all analyzed aspects, presenting less than half of the wear shown by the low alloyed steel when processing scrap under the same conditions. Other additional operational benefits also were obtained as a decrease in the set up time, being the material of choice for this task.

The typical methodology for analytically designing a wind turbine blade is by means of blade element momentum (BEM) theory, whereby the aerofoil angle of attack is optimized to achieve a maximum lift-to-drag ratio. This research aims to show that an alternative optimisation methodology could yield better results, especially in gusty and turbulent wind conditions. This alternative method looks at increasing the aerofoil Reynolds number by increasing the aerofoil chord length. The increased Reynolds number generally increases the e_ectiveness of the aerofoil which would result in a higher or similar lift-to-drag ratio (even at the decreased angle of attacked require to maintain the turbine thrust coe_cient). The bene_t of this design is a atter power curve which causes the turbine to be less sensitive to uctuating winds. Also, the turbine has more torque at startup, allowing for operatation in lower wind speeds. This research is assumed to only be applicable to small wind turbines which operated in a low Reynolds number regime (<500 000), where Reynolds number manipulation is most advantageous.