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1
Caldeira, Miguel António Barreto. "Projecto e implementação de FBGs para aplicações em telecomunicações." Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/3566.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesNum contexto de grande desenvolvimento e massificação das telecomunicações, provocada pela necessidade intrínseca de serviços inerentes ao contacto permanente e global de um grande número de indivíduos, têm surgido vários dispositivos que tentam responder a este novo contexto, aumento de largura de banda e processamento totalmente óptico. Um dos dispositivos importante neste cenário, nomeadamente em operações de filtragem e compensação de dispersão cromática no domínio óptico, é a rede de Bragg em fibra óptica. Como tal o objectivo principal deste trabalho é produzir FBGs para aplicações em telecomunicações e aperfeiçoar a plataforma que permite estas implementações. Inicialmente apresenta-se o princípio de funcionamento e tipos de redes Bragg. De modo a simular a resposta em amplitude e fase de redes de Bragg desenvolveu-se um software com base no método da matriz transferência. Seguidamente, estudaram-se métodos de implementação de redes de Bragg com perfil de sinc e com perfil de chirp equivalente, que permitissem obter FBGs com respostas adequadas respectivamente à filtragem óptica em sistemas multicanal, e à compensação de dispersão Procedeu-se ao estudo do sistema de gravação implementado no Instituto de Telecomunicações – Pólo de Aveiro e dos algoritmos de implementação já desenvolvidos, em especial o método de stitching. Por fim, de modo a poder caracterizar-se e retirar conclusões das redes de Bragg implementadas, efectuaram-se projectos, simulações, e gravações de redes e compararam-se as respostas das redes Bragg gravadas com as simuladas, confirmando-se a validade do procedimento suportado pela plataforma disponível.
In the subject of great development and growing field of telecommunications provoked by intrinsic necessity of inherent services of permanent contact and globally, a large number of individuals have suggested various devices that attempt to respond to this new subject, increased bandwidth and all optical processing. One of important devices in this scenario, namely in operations of filtering and compensation of chromatic dispersion in optical domain, is Bragg gratings in optical fiber. As such the main objective of this work is produce FBGs for applications in telecommunications and improve the platform that allows these implementations. Initially presents the principle function and types of Bragg’s gratings. In order to simulate the response amplitude and phase developed software based on the matrix method of transfer. Next, we studied methods of implementation of Bragg’s gratings with sinc profile and chirp equivalent profile, which would allow for FBGs with appropriate responses respectively to the optical filtering in multichannel systems, and the dispersion compensation. In this sense, recording the gratings were proceeded the study the recording system to be incorporated in the Institute of Telecommunications-Pólo de Aveiro, and in the implementation algorithms already developed, especially for the stitching method. Lastly, in characterizing and drawing conclusions of the applied gratings, simulations, projects, and recordings of Bragg’s gratings were carried out, in comparing the results of the recordings to the simulations, confirming the validity of the procedure supported by the available platform.
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Santos, João Miguel Sarabando. "FBGs avançadas para sistemas de comunicação em fibra óptica." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2135.
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Mestrado em Engenharia Electrónica e TelecomunicaçõesIniciou-se este trabalho com o estudo das redes de Bragg em fibra óptica, propriedades espectrais e espaciais, identificando os seus principais parametros físicos e o impacto que estes têm na sua resposta em amplitude e fase. Coincidente com esta fase, desenvolveu-se um algoritmo de simulação de redes Bragg baseado no método da matriz de transferência, com o objectivo de uma melhor compreensão das redes Bragg em fibra óptica. De seguida, procedeu-se ao estudo do sistema de gravação implementado no Instituto de Telecomunicações – Pólo de Aveiro e dos algoritmos já desenvolvidos, com especial atenção para um algoritmo de implementação de redes de Bragg através do método de stitching. De seguida, iniciou-se o desenvolvimento do software. Efectuaram-se simulações, projecto e gravações de redes Bragg e compararam-se as respostas das redes Bragg gravadas com as simuladas. Finalmente, caracterizaram-se e analisaram-se algumas redes de Bragg implementadas, utilizando um simulador de sistemas de comunicações ópticas.
This work started with the study of the Fiber Bragg Gratings and their spectral and spatial properties, as well as the identification of the main physical parameters associated and their impact in the amplitude and phase response. Simultaneously, a FBG simulation algorithm was developed based on the transfer function method, for a better understanding of the FBGs characteristics. Then, we proceed to the study of the recording system at the Instituto de Telecomunicações - Pólo de Aveiro, as well as the study of the developed algorithms, with particular attention to an implementation algorithm considering the stitching method. The development of the software followed. Several simulations, designs and FBG recordings were performed and the responses of the recorded FBGs were compared to the expected ones. Finally, a number designed FBGs were characterized and tested, using an optical communication system simulator.
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Hole, Erik Lillebø. "Optical Fiber sensing of acoustic waves using overlapping FBGs." Thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-37779.
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The objective of this thesis was to investigate if an optical fiber sensing method with the use of two overlapping fiber Bragg gratings to measure Lamb wave $S_0$ modes in a steel plate, and how it would compare to traditional PZT transducers. A solution was proposed where the use of an optical fiber sensing system was built and took advantage of the strain dependence of a fiber Bragg grating mounted to a steel plate. Together with an overlapping reference fiber Bragg grating, the system can translate strain to light intensity. A method of controlling the Bragg wavelength of the reference fiber Bragg grating to optimize the overlap between the two fiber Bragg gratings, enabling the system to compensate for drift in the sensing fiber Bragg grating. Testing of the system was performed and yielded promising results, being able to measure the Lamb wave signal from the steel plate. The system showed some sensitivity limitations and signal to noise ratio, as well as the software created to compensate for the drift. With the improvement proposed for further work with the system in terms of improving the system's sensitivity, signal to noise ratio and drift control should make the system able to perform at levels as traditional PZT transducers.
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Santos, Ana Vanessa Guindeira dos. "Implementação de FBGs para sistemas de comunicação em fibra óptica." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/1924.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesO presente trabalho tem por objectivo o desenvolvimento de um algoritmo de apoio à gravação de redes de Bragg em fibra óptica, baseado no método de stitching, por sobreposição e interferência de secções de perturbação do índice de refracção com um comprimento (step) definido. Começou por se efectuar uma abordagem teórica ao funcionamento das redes de Bragg, identificando-se os principais parâmetros físicos da perturbação referida, que têm impacto na sua resposta em amplitude e fase. Posteriormente, analisou-se o sistema implementado para a gravação de redes de Bragg, e desenvolveu-se um algoritmo de apoio a essa gravação. Finalmente, para um perfil de apodização definido, procedeu-se à gravação de redes de Bragg com diferentes steps, suportada pelo software implementado, e compararam-se as respostas medidas e simuladas em cada caso. Analisou-se também, por simulação, o impacto do step e resposta correspondente no desempenho de um sistema de comunicações ópticas.
This work focuses on the development of an algorithm to support a Bragg gratings’ recording system, based on the stitching method, by overlapping sections of perturbed refraction index with a defined length (step). First, we made a theoretical approach to the operation of Bragg gratings, identifying the main physical parameters of the referred perturbation that impact their response, both in amplitude and phase. Subsequently, we analyzed the implemented system, and developed an algorithm to support it. Finally, for a defined profile of apodization, we proceeded to the Bragg filters implementation, with different recording steps, supported by the developed software, and compared to the measured and simulated responses in each case. Finally, we simulated an optical communications system and analyzed the impact of the recording step and consequent response in the system’s performance.
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Batista, Fabio Júnio Alves. "Sistema embarcado para detecção e determinação da posição dos picos de bragg em FBGs." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1551.
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Neste trabalho foi desenvolvido um software para ser embarcado em um sistema autônomo baseado em arquitetura ARM, como o objetivo de detecção da posição de picos de um espectro refletido por uma rede de Bragg gravada em fibra óptica (FBG) e interrogadas pelo Interrogador comercial I-MON. O software foi desenvolvido para ser embarcado em uma plataforma pcDuino o qual permite o monitoramento em tempo real e os dados podem ser visualizados em uma interface gráfica. Para detecção da posição dos picos foi aplicado um algoritmo que aproxima os dados experimentais por uma função gaussiana através do método dos mínimos quadrados. O sistema foi caracterizado a partir do monitorado da temperatura sobre a superfície de uma célula termoelétrica, as leituras foram realizadas entre 0°C e 100°C. Comparando a posição do pico de Bragg registrada com o sistema desenvolvido e com o software Ext_Evaluation disponibilizado pelo fabricante do interrogador I-MON, verifica-se diferença média de aproximadamente 0,010 nm. A diferença média na posição do pico de Bragg é superior a resolução de 0,5 pm informada pelo fabricante do interrogador I-MON. Contudo, geralmente interessa saber a variação na posição do pico de Bragg e não a sua posição absoluta no espectro. Assim, pode-se concluir que o algoritmo desenvolvido é eficiente na detecção da variação na posição do pico do espectro refletido por um sensor FBG.This work developed a software to be embedded in an autonomous system based on ARM architecture, as the goal of detecting the peak position of a spectrum reflected by a Bragg grating written to optical fiber (FBG) and interrogated by the commercial Interrogator I-MON 512 E. The software was developed for the ARM architecture using the pcDuino platform which allows real-time monitoring and the data can be viewed in a graphical interface. For detecting the position of the peaks was applied to an algorithm that approximates the experimental data by a Gaussian function by the method of least squares. The system is characterized from the monitored temperature on the surface of a thermoelectric cell readings were made between 0°C and 100°C. Comparing the position of the Bragg peak registered with the system developed and the Ext_Evaluation software provided by the manufacturer of the interrogator I-MON it appears the average difference is approximately 0,010 nm. The mean difference in the position of the Bragg peak is less than 0.5 pm resolution is informed by the manufacturer of the interrogator I-MON. However, usually interested in changes in position of the Bragg peak instead of on absolute position in the spectrum. Thus, it can be concluded that the proposed algorithm is effective detecting the variation in position of Bragg peaks using FBG sensors.
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Barrera, Vilar David. "Diseño, fabricación y caracterización de FBGs e interferómetros en fibra óptica para la monitorización en ambientes adversos." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/33399.
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En esta tesis doctoral se presenta el diseño, la implementación y la caracterización de sensores
en fibra óptica para la monitorización de diversas magnitudes en ambientes adversos. Se
entiende como ambientes adversos aquellas condiciones ambientales externas a los sensores
que por su naturaleza dificultan el uso y la fiabilidad a largo plazo de los sistemas de
monitorización. Existe una gran variedad de ambientes adversos tales como temperaturas
extremas, altas presiones, ambientes químicos o ionizantes, vibraciones o impactos mecánicos,
entre otros. Este trabajo de tesis, realizado en el Grupo de Comunicaciones Ópticas y Cuánticas
(GCOC) del Instituto de Telecomunicaciones y Aplicaciones Multimedia (ITEAM) de la
Universitat Politècnica de València así como el trabajo realizado durante la estancia en la
School of Engineering and Applied Science de la Aston University, contempla algunos de estos
escenarios, por lo que en el diseño e implementación de los sensores ópticos se han empleado
distintas tecnologías ópticas, como las redes de difracción de Bragg (FBGs) o los
interferómetros ópticos, con el fin de optimizar las prestaciones de los sensores.
En primer lugar, se ha realizado un estudio exhaustivo de las redes de difracción de Bragg
regeneradas (RFBGs) para la medida de temperaturas extremas, cercanas a los 1300ºC en
algunos casos. Este estudio comprende desde el proceso de fabricación de estos dispositivos
fotónicos hasta la caracterización como sensores de temperatura y el estudio de la estabilidad
térmica a largo plazo. Se ha realizado también un estudio teórico y experimental sobre la
multiplexación de interferómetros modales que, por su sensibilidad y robustez, son muy
apropiados para su uso en condiciones ambientales adversas. La técnica de multiplexación
desarrollada permite multiplexar los interferómetros modales en distintas configuraciones
minimizando la interferencia entre ellos. Por último, se muestra la implementación de un
sistema de inscripción de FBGs en fibras ópticas de polímeros y el uso de los dispositivos
obtenidos para el diseño, la implementación y la caracterización de sensores ópticos para la
medida de curvaturas, grandes deformaciones y deformaciones dinámicas.Barrera Vilar, D. (2013). Diseño, fabricación y caracterización de FBGs e interferómetros en fibra óptica para la monitorización en ambientes adversos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/33399
TESIS
Premiado
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McCausland, Jeffrey A. "Effects Of Applying Longitudinal Magnetic Fields To Fibers Containing Bragg Gratings." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1375109817.
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Hervás, Peralta Javier. "Design of photonic sensors based on cavities and new interrogation techniques." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/119754.
Full textAbstract:
[ES] Los sensores ópticos son dispositivos fotónicos sensibles a determinadas magnitudes que se usan precisamente para medir, ya sea de forma absoluta o relativa, esas magnitudes. Medir la temperatura, la presión, la tensión, la humedad o la presencia de un determinado gas son algunas de las funcionalidades que llevan a cabo estos sensores. A lo largo de las últimas décadas multitud de sensores y técnicas de interrogación han sido desarrolladas, lo que ha tenido un increíble impacto en multitud de áreas. Uno de los ejemplos más claro es la arquitectura civil, donde los sensores fotónicos juegan un papel fundamental en la monitorización del estado de las estructuras.
A pesar de los buenos resultados conseguidos por los sensores ópticos hasta la fecha, las técnicas de interrogación desarrolladas hasta ahora muestran algunas desventajas. Tiempos de medida altos, baja resolución o una gran complejidad son algunas de ellas. En esta tesis doctoral se presenta el diseño y caracterización de diversos sensores fotónicos basados en las ya conocidas redes de difracción de Bragg así como la implementación de nuevas técnicas de interrogación de dichos sensores para intentar eliminar o reducir esas desventajas. Las técnicas de interrogación desarrolladas en este trabajo se basan en la fotónica de microondas, donde la interacción entre las señales ópticas y eléctricas se usa para detectar en este caso los cambios en una determinada magnitud.
Las técnicas desarrolladas en este trabajo buscan ser lo más versátiles y escalables posibles para así poder adaptarse a los requerimientos de diferentes escenarios. Encontramos así técnicas que permiten interrogar a miles de sensores con una gran resolución y sensibilidad así como también técnicas de interrogación de sensores puntuales con una enorme sensibilidad y simplicidad tanto en la interrogación como en el sistema usado para ello. También están presentes los resultados obtenidos mediante la colaboración con el instituto de investigación sueco ACREO para el desarrollo de un sensor de campo eléctrico basado en fibras polarizadas donde se han fabricado varias redes de difracción de Bragg.[CAT] Els sensors òptics son dispositius fotònics sensibles a determinades magnituds que s'usen precisament per a mesurar, ja siga de forma absoluta o relativa, aquestes magnituds. Mesurar la temperatura, la pressió, la tensió, la humitat o la presència d'un determinat gas són algunes de les funcionalitats que realitzen aquestos sensors. Al llarg de les últimes dècades multitud de sensors i tècniques d'interrogació han sigut desenvolupades, i això ha tingut un impacte increïble a multitud d'àrees. Un dels exemples més clar es l'arquitectura civil, on aquestos sensors juguen un paper fonamental en la monitoratge de l'estat de les estructures. Encara que els resultats aconseguits han sigut bons, les tècniques d'interrogació desenvolupades fins ara mostren alguns desavantatges. Temps de mesurament alt, baixa resolució o una gran complexitat són algun d'ells. A aquesta tesi doctoral es presenta el disseny i caracterització de diversos sensors fotònics basats en les ja conegudes xarxes de difracció de Bragg així com l'implementació de noves tècniques d'interrogació per a intentar eliminar o reduir aquestos inconvenients. Les tècniques d'interrogació desenvolupades en aquest treball es basen en la fotònica de microones, on l'interacció entre les senyals òptiques i elèctriques s'usa per a detectar en aquest cas els canvis en una determinada magnitud. Les tècniques desenvolupades en aquest treball busquen ser el més versàtils i escalables possibles per a poder adaptar-se als requeriments dels diferents escenaris. Trobem així tècniques que permeten interrogar milers de sensors amb una gran resolució i sensitivitat però també tècniques que permeten interrogar sensors puntuals amb una increïble sensitivitat mostrant una gran simplicitat en el seu disseny. També estan presents els resultats obtinguts mitjançant la col¿laboració amb l'institut d'investigació suec ACREO per al desenvolupament d'un sensor de camp eléctric basat en FBGs i en fibres polaritzades.
[EN] Optical sensors are photonic devices sensitive to different magnitudes that are used precisely to measure, in an absolute or a relative way, these magnitudes. These optical sensors are nowadays used to measure temperature, pressure, strain, humidity or the presence of a particular gas. In the past few decades a multitude of photonic sensors and different interrogation techniques have been developed, which had a great impact in dozens of different fields. One of the best examples is civil architecture, in which photonic sensors play a fundamental role in order to monitor the condition of the structures. Despite of the good results showed by photonic sensors, the interrogation techniques used show different drawbacks. A large measurement time, low resolution or great complexity are some of them. In this doctoral thesis the design and characterization of a set of different photonic sensors based on the already known fiber Bragg gratings, along with the implementation of new interrogation techniques, are used in order to eliminate or at least reduce these problems. The interrogation techniques developed in this work are based on Microwave Photonics techniques, in which the interaction between optical and electrical signals is used to detect in this case the changes in a particular magnitude. The techniques showed in this work have been designed in order to be as versatile and scalable as possible to have the opportunity to adapt to any requirement in different scenarios. In this work techniques that are able to interrogate hundreds or even thousands of sensors with great sensitivity and resolution can be found in addition to techniques that are developed to interrogate individual sensors with an enormous sensitivity. The work carried out in collaboration with the Swedish research institute ACREO, based on the development of an electric field sensor based on poled fibers together with FBGs is also present.
Hervás Peralta, J. (2019). Design of photonic sensors based on cavities and new interrogation techniques [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/119754
TESIS
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Graziano, Maria. "Updating of Finite Element Models using static and dynamic optical strains with application to damage assessment." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
Find full textAbstract:
In the recent years, vibration-based structural damage identification has been subject of significant research in structural engineering. The basic idea of vibration-based methods is that damage induces mechanical properties changes that cause anomalies in the dynamic response of the structure, which measures allow to localize damage and its extension. Vibration measured data, such as frequencies and mode shapes, can be used in the Finite Element Model Updating in order to adjust structural parameters sensible at damage (e.g. Young’s Modulus). The novel aspect of this thesis is the introduction into the objective function of accurate measures of strains mode shapes, evaluated through FBG sensors.
After a review of the relevant literature, the case of study, i.e. an irregular prestressed concrete beam destined for roofing of industrial structures, will be presented. The mathematical model was built through FE models, studying static and dynamic behaviour of the element.
Another analytical model was developed, based on the ‘Ritz method’, in order to investigate the possible interaction between the RC beam and the steel supporting table used for testing.
Experimental data, recorded through the contemporary use of different measurement techniques (optical fibers, accelerometers, LVDTs) were compared whit theoretical data, allowing to detect the best model, for which have been outlined the settings for the updating procedure.
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A, Meckstroth Gregory. "FBCs for NBDs in Cincinnati, Ohio." Cincinnati, Ohio : University of Cincinnati, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1243302122.
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Thesis (Master of Community Planning)--University of Cincinnati, 2009.Advisor: Menelaos Triantafillou. Title from electronic thesis title page (viewed Aug. 12, 2009). Includes abstract. Keywords: Form Based Codes; Cincinnati, Ohio; FBC; NBD; Neighborhood Business District. Includes bibliographical references.
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Meckstroth, Gregory A. Jr. "FBCs for NBDs in Cincinnati, Ohio." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1243302122.
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Gray, Shani P. "Faith-based organizations (FBOs) and community crime control initiatives." [Bloomington, Ind.] : Indiana University, 2005. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3185394.
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Thesis (Ph. D.)--Indiana University, 2005.Source: Dissertation Abstracts International, Volume: 66-08, Section: A, page: 3101. Chair: Steven Chermak. Title from dissertation home page (viewed Oct. 5, 2006).
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Ricchiuti, Amelia Lavinia. "Design and fabrication of customized fiber gratings to improve the interrogation of optical fiber sensors." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/66343.
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[EN] Fiber grating sensors and devices have demonstrated outstanding capabilities in both telecommunications and sensing areas, due to their well-known advantageous characteristics. Therefore, one of the most important motivations lies in the potential of customized fiber gratings to be suitably employed for improving the interrogation process of optical fiber sensors and systems.
This Ph.D. dissertation is focused on the study, design, fabrication and performance evaluation of customized fiber Bragg gratings (FBGs) and long period gratings (LPGs) with the double aim to present novel sensing technologies and to enhance the response of existing sensing systems. In this context, a technique based on time-frequency domain analysis has been studied and applied to interrogate different kind of FBGs-based sensors. The distribution of the central wavelength along the sensing structures has been demonstrated, based on a combination of frequency scanning of the interrogating optical pulse and optical time-domain reflectometry (OTDR), allowing the detection of spot events with good performance in terms of measurand resolution. Moreover, different customized FBGs have been interrogated using a technology inspired on the operation principle of microwave photonics (MWP) filters, enabling the detection of spot events using radio-frequency (RF) devices with modest bandwidth. The sensing capability of these technological platforms has been fruitfully employed for implementing a large scale quasi-distributed sensor, based on an array of cascaded FBGs. The potentiality of LPGs as fiber optic sensors has also been investigated in a new fashion, exploiting the potentials of MWP filtering techniques. Besides, a novel approach for simultaneous measurements based on a half-coated LPG has
been proposed and demonstrated. Finally, the feasibility of FBGs as selective wavelength filters has been exploited in sensing applications; an alternative approach to improve the response and performance of Brillouin distributed fiber sensors has been studied and validated via experiments. The performance of the reported sensing platforms have been analyzed and evaluated so as to characterize their impact on the fiber sensing field and to ultimately identify the use of the most suitable technology depending on the processing task to be carried out and on the final goal to reach.[ES] Los sensores y dispositivos en fibra basados en redes de difracción han mostrado excepcionales capacidades en el ámbito de las telecomunicaciones y del sensado, gracias a sus excelentes propiedades. Entre las motivaciones más estimulantes destaca la posibilidad de fabricar redes de difracción ad-hoc para implementar y/o mejorar las prestaciones de los sensores fotónicos. Esta tesis doctoral se ha enfocado en el estudio, diseño, fabricación y evaluación de las prestaciones de redes de difracción de Bragg (FBGs) y de redes de difracción de periodo largo (LPGs) personalizadas con el fin de desarrollar nuevas plataformas de detección y a la vez mejorar la respuesta y las prestaciones de los sensores fotónicos ya existentes. En este contexto, una técnica basada en el análisis tiempofrecuencia se ha estudiado e implementado para la interrogación de sensores en fibra basados en varios tipos y modelos de FBGs. Se ha analizado la distribución de la longitud de onda central a lo largo de la estructura de sensado, gracias a una metodología que conlleva el escaneo en frecuencia del pulso óptico incidente y la técnica conocida como reflectometria óptica en el dominio del tiempo (OTDR). De esta manera se ha llevado a cabo la detección de eventos puntuales, alcanzando muy buenas prestaciones en términos de resolución de la magnitud a medir. Además, se han interrogado varias FBGs a través de una técnica basada en el principio de operación de los filtros de fotónica de microondas (MWP), logrando así la detección de eventos puntuales usando dispositivos de radio-frecuencia (RF) caracterizados por un moderado ancho de banda. La capacidad de sensado de estas plataformas tecnológicas ha sido aprovechada para la realización de un sensor quasi-distribuido de gran alcance, formado por una estructura en cascada de muchas FBGs. Por otro lado, se han puesto a prueba las capacidades de las LPGs como sensores ópticos según un enfoque novedoso; para ello se han aprovechados las potencialidades de los filtros de MWP. Asimismo, se ha estudiado y demostrado un nuevo método para medidas simultáneas de dos parámetros, basado en una LPG parcialmente recubierta por una película polimérica. Finalmente, se ha explotado la viabilidad de las FBGs en cuanto al filtrado selectivo en longitud de onda para aplicaciones de sensado; para ello se ha propuesto un sistema alternativo para la mejora de la respuesta y de las prestaciones de sensores ópticos distribuidos basados en el scattering de Brillouin. En conclusión, se han analizado y evaluado las prestaciones de las plataformas de sensado propuestas para caracterizar su impacto en el ámbito de los sistemas de detección por fibra y además identificar el uso de la tecnología más adecuada dependiendo de la tarea a desarrollar y del objetivo a alcanzar.
[CAT] Els sensors i dispositius en fibra basats en xarxes de difracció han mostrat excepcionals capacitats en l'àmbit de les telecomunicacions i del sensat, gràcies a les seus excel¿lents propietats. Entre les motivacions més estimulants destaca la possibilitat de fabricar xarxes de difracció ad-hoc per a implementar i/o millorar les prestacions de sensors fotònics. Esta tesi doctoral s'ha enfocat en l'estudi, disseny, fabricació i avaluació de les prestacions de xarxes de difracció de Bragg (FBGs) i de xarxes de difracció de període llarg (LPGs) personalitzades per tal de desenvolupar noves plataformes de detecció i al mateix temps millorar la resposta i les prestacions dels sensors fotònics ja existents. En este context, una tècnica basada en l'anàlisi temps-freqüència s'ha estudiat i implementat per a la interrogació de sensors en fibra basats en diversos tipus i models de FBGs. S'ha analitzat la distribució de la longitud d'ona central al llarg de l'estructura de sensat, gràcies a una metodologia que comporta l'escaneig en freqüència del pols òptic incident i la tècnica coneguda com reflectometria òptica en el domini del temps (OTDR). D'esta manera s'ha dut a terme la detecció d'esdeveniments puntuals, aconseguint molt bones prestacions en termes de resolució de la magnitud a mesurar. A més, s'han interrogat diverses FBGs a través d'una tècnica basada en el principi d'operació dels filtres de fotònica de microones (MWP), aconseguint així la detecció d'esdeveniments puntuals utilitzant dispositius de ràdio-freqüència (RF) caracteritzats per un moderat ample de banda. La capacitat de sensat d'aquestes plataformes tecnològiques ha sigut aprofitada per a la realització d'un sensor quasi-distribuït a llarga escala, format per una estructura en cascada de moltes FBGs. D'altra banda, s'han posat a prova les capacitats de les LPGs com a sensors òptics segons un enfocament nou; per a això s'han aprofitat les potencialitats dels filtres de MWP. Així mateix, s'ha estudiat i demostrat un nou mètode per a mesures simultànies de dos paràmetres, basat en una LPG parcialment recoberta per una pel¿lícula polimèrica. Finalment, s'ha explotat la viabilitat de les FBGs pel que fa al filtrat selectiu en longitud d'ona per a aplicacions de sensat; per això s'ha proposat un sistema alternatiu per a la millora de la resposta i de les prestacions de sensors òptics distribuïts basats en el scattering de Brillouin. S'han analitzat i avaluat les prestacions de les plataformes de sensat propostes per a caracteritzar el seu impacte en l'àmbit dels sistemes de detecció per fibra i a més identificar l'ús de la tecnologia més adequada depenent de la tasca a desenvolupar i de l'objectiu a assolir.
Ricchiuti, AL. (2016). Design and fabrication of customized fiber gratings to improve the interrogation of optical fiber sensors [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/66343
TESIS
Premiado
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Morali, Ekrem Mehmet. "Mathematical Modeling Of Fbcs Co-fired With Lignite And Biomass." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608552/index.pdf.
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Increasing environmental legislations on pollutant emissions originated from fossil fuel combustion and intention of increasing the life of existing fossil fuels give rise to the use of renewable sources. Biomass at this juncture, with its renewable nature and lower pollutant emission levels becomes an attractive energy resource. However, only seasonal availability of biomass and operation problems caused by high alkaline content of biomass ash restrict its combustion alone. These problems can be overcome by co-combustion of biomass with lignite. With its high fuel flexibility and high combustion efficiency, fluidized bed combustion is the most promising technology for co-firing. To improve and optimize the operation of co-firing systems a detailed understanding of co-combustion of coal and biomass is necessary, which can be achieved both with experiments and modeling studies. For this purpose, a comprehensive system model of fluidized bed combustor, previously developed and tested for prediction of combustion behaviour of fluidized bed combustors fired with lignite was extended to co-firing lignite with biomass by incorporating volatile release, char combustion and population balance for biomass.
The model predictions were validated against experimental measurements taken on METU 0.3 MWt AFBC fired with lignite only, lignite with limestone addition and about 50/50 lignite/olive residue mixture with limestone addition. Predicted and measured temperatures and concentrations of gaseous species along the combustor were found to be in good agreement. Introduction of biomass to lignite was found to decrease SO2 emissions but did not affect NO emissions significantly.
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Xu, Xingyuan. "Improving the performance of FBG sensing system." Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20070110.144936/index.html.
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Sethuraman, Gopakumar. "Fiber Bragg Grating (FBG) Based Chemical Sensor." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1575.
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In this work, reagentless fiber optic-based chemical sensors for water quality testing were fabricated by coating fiber Bragg gratings with the glassy polymer cellulose acetate. With this polymeric matrix capable of localizing or concentrating chemical constituents within its structure, immersion of the coated grating in various chemical solutions causes the rigid polymer to expand and mechanically strain the glass fiber. The corresponding changes in the periodicity of the grating subsequently result in altered Bragg-reflected responses. A high-resolution tunable fiber ring laser interrogator is used to obtain room temperature reflectance spectrograms from two fiber gratings at 1550 nm and 1540 nm wavelengths. Rapidly swept measurements of the full spectral shapes yield real-time chemical detection and identification. With deionized water as a reference, wavelength shifts in the reflectivity transition edge from –82 pm to +43 pm and changes in response bandwidth from –27 pm to +42 pm are used to identify uniquely a diverse selection of chemical analytes.
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Kuna, Kranthi. "Mix design considerations and performance characteristics of foamed bitumen mixtures (FBMs)." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28857/.
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The sustainability issues in pavement materials and design form a strong incentive for the present work. Using recycled materials in pavements is a sustainable practice that is gaining adoption, particularly for flexible (bituminous) pavements. One approach is to incorporate large quantities of Reclaimed Asphalt Pavement (RAP) into base and sub-base applications for pavement construction. Numerous studies have reported that RAP can be reused as an aggregate in Hot Mix Asphalt (HMA) as well as in cold mix asphalt, granular base, sub-base, and subgrade courses. Cold recycling technology, like hot mix technology, has also become popular in various countries for rehabilitation of damaged bituminous pavements. RAP stabilized with bitumen emulsion and foamed bitumen has been used as a base layer. The present study focuses on Foamed Bitumen treated Mixes (FBMs). Most of the agencies which use FBMs have their own mix design procedures which are the result of numerous efforts over decades. In spite of all these efforts, Foamed Bitumen application in cold recycling in the United Kingdom suffers from the lack of a standardised mix design procedure. To overcome this, the present research objective was to develop a mix design procedure by identifying critical mix design parameters. The mix design parameters that were optimised were Foamed Bitumen content, mixing water content (MWC), and compaction effort. Special attention was given to the simplest yet crucial mix design consideration of FBMs; curing. The thesis also attempted to simulate what should be expected in terms of the performance of flexible pavements containing FBMs as road base. The mix design parametric study was initially carried out on FBMs with virgin limestone aggregate (VA) without RAP material and a mix design procedure was proposed. Optimum MWC was achieved by optimising mechanical properties such as Indirect Tensile Stiffness Modulus (ITSM) and Indirect Tensile Strength (ITS-dry and ITS-wet). A rational range of 75-85% of Optimum Water Content (OWC) obtained by the modified Proctor test was found to be the optimum range of MWC that gives optimum mechanical properties for FBMs. The proposed methodology was also found to apply to FBMs with 50% RAP and 75% RAP. It was also found that the presence of RAP influenced the design FB content, which means that treating RAP as black rock in FBM mix design is not appropriate. This work also evaluated the validity of the total fluid (water + bitumen) concept which is widely used in bitumen-emulsion treated mixes. The present work was also intended to better understand the curing mechanism of FBMs and to lessen the gap between laboratory curing and field evolution of these mixtures. This was achieved by evaluating different curing regimes that are being followed by different agencies and researchers, as well as identifying important parameters that affect curing. In achieving this, a link was established between laboratory mix design and field performance by evaluating applicability of the maturity method. The curing regime study provided a valid investigation into the behaviour of FBM taking into account the effect of temperature, curing conditioning (Sealed or Unsealed), curing duration and the influence of cement with different curing regimes. It was found that the temperature is as important a parameter as time, as temperature has a greater influence on curing rate and also on bitumen properties. Moreover, higher curing temperatures resulted in higher rate of stiffness gain. This trend is not only because of rapid water loss but also implies an increase in binder stiffness at higher curing temperatures. Though the presence of RAP improved the early stage stiffness of FBMs, it slowed down the rate of water loss from the specimens which resulted in smaller stiffness values at a later stage. The experimental results also indicated that cement addition has no influence on water loss trends, but improved the stiffness significantly during all stages of curing. The study also evaluated the applicability of the maturity method as a tool to assess the in-situ characteristic of FBM layers in the pavement. It was found that replacing the time term with an equivalent age term in the maturity function aided in estimating stiffness rather than relative stiffness. This was possible because of the characteristic curing of FBM in which the limiting stiffness these mixtures reach strongly depends on the curing temperature at least for the length of the curing stages considered in the present study. A strong correlation was found between maturity and the stiffness values obtained from the laboratory tests which resulted in development of maturity-stiffness relationships. The application of the method to assess the in-situ stiffness was presented using three hypothetical pavement sections. The results showed the influence of ambient temperature and the importance of cement addition to FBMs. The permanent deformation resistance was assessed by performing RLAT tests on cylindrical specimens compacted by gyratory compactor. The RLAT test results indicate that both test temperature and stress level have significant influence on permanent deformation characteristics as expected. The effect of stress on permanent deformation was increased with increase in test temperature. It was also found that from limited tests and mixture combinations, RAP content has only a slight influence on permanent deformation of FBMs. However, the presence of cement led to significant improvement. FBMs were also found to be less temperature susceptible than HMA in terms of permanent deformation and, within FBMs, mixtures with cement were found to be more sensitive than FBMs without any cement. For assessing the fatigue performance of FBMs, the ITFT was initially used to investigate the effect of cement on the fatigue life. The ITFT tests results showed that the FBMs without cement (50%RAP-FBM) have lower fatigue life than HMA (DBM90) at any initial strain level. Nevertheless, similar to permanent deformation, the fatigue life was improved with the addition of 1% cement to FBMs. However, the above discussion was not found to be completely valid when uniaxial tests were carried out. In stress controlled uniaxial tests, a sinusoidal load of 1Hz frequency was applied axially to induce tensile strain in the radial direction. The failure criterion considered in the study was the number of cycles to reach 50% stiffness and this was plotted against the measured initial strain values. Results indicated that there was not much difference in fatigue life among different mixtures and also between FBM and HMA. However, stiffness evolution curves showed that FBMs fail in a different pattern compared to HMA. Unlike HMA, which showed a three stage evolution process, for FBMs the stiffness actually increased initially to reach a maximum and decreased at a slower rate until failure. It was also found that by plotting curves according to Hopman et al.,(1989) which identifies the fatigue failure transition point, use of the 50% stiffness criterion for fatigue life evaluation is not a conservative approach. Uniaxial tests also revealed that, although in fatigue the FBMs were found to behave differently from HMA, in terms of permanent deformation, FBMs behave similarly to HMA in that a steady state strain rate was achieved.
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Yeo, Jackson Teck Leong. "Application of FBG-based sensors in built environment." Thesis, City University London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440691.
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Lopes, Pedro José Ramos. "Aplicação de sensores FBG em modelos para injeção." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/12548.
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Mestrado em Engenharia MecânicaCom o interesse crescente em analisar detalhadamente o comportamento do material fundido no processo de moldação por injeção, procedeu-se à aplicação de sensores de Bragg em fibra ótica (FBG) para medir temperaturas no interior do molde. Ainda hoje é uma incógnita precisar o comportamento do material polimérico no momento da injeção, principalmente a distribuição de temperaturas no perfil da frente de enchimento. Para cumprir o objetivo da dissertação foram gravadas 12 redes de Bragg em 4 fibras óticas distintas com o objetivo de criar uma malha 2D no interior da placa fixa do molde, a 3 mm do plano de partição. As redes foram gravadas de forma estratégica a coincidir com a superfície moldante que está em contacto com as peças que são injetadas. Para que as redes de Bragg ficassem operacionais, foram necessárias algumas etapas. A rede de Bragg é inscrita no núcleo da fibra ótica através de um método de gravação por laser. Com o intuito de conhecer o comportamento térmico de cada sensor de Bragg às variações de temperatura, procedeu-se a um ensaio de caracterização térmica em ambiente controlado. De seguida, foram instaladas no molde de injeção plástica as fibras óticas com os sensores e sequentemente elaborados alguns ensaios de injeção, cada um com aproximadamente 40 ciclos de moldação. Os resultados das experiências foram muitos semelhantes, e indicam que os sensores detetaram valores máximos de temperatura próximos dos 57 °C. Em cada ciclo de moldação as variações registadas nos sensores eram praticamente constantes e aproximadamente 3 ou 2 °C, conforme o sensor em causa. Antes dos ensaios no molde de injeção, foi realizada uma simulação numérica no software Autodesk Moldflow Synergy 2012. Esta serviu para prever os comportamentos térmicos do ciclo de moldação e também para determinar os valores de alguns dos parâmetros de operação na máquina de injeção. Esta tecnologia baseada em redes de Bragg é única, pois permite a disposição de inúmeros sensores de temperatura ao longo de uma fibra ótica, ocupando assim um volume muito reduzido. Estas vantagens aliadas à excelente resolução na aquisição de dados e à rápida resposta a impulsos térmicos fazem dos sensores FBG uma alternativa a ser tida em conta para futuros trabalhos relacionados com aplicações térmicas.
With the growing interest in thoroughly analyzing the behavior of the melted material in the process of injection molding, Fiber Bragg Gratings (FBG) were applied to measure temperatures in the mold interior. Still today it’s unknown to precise the polymeric material behavior in the fill time, especially the temperature distribution in the front flow profile. To fulfill the purpose of the dissertation12 Bragg gratings were recorded in 4 different optical fibers with the purpose of creating a two-dimensional mesh in the injection mold’s interior, 3 mm apart from the parting line. The gratings were inscribed in a strategic way to be placed over the molding surface which is in contact with the test specimens that are being injected. For the Bragg gratings become operational, several steps were required. The Bragg grating is written in the fiber’s core throughout a method using laser. An experience of thermal characterization in a controlled environment was mandatory to obtain the thermal behavior of each Bragg sensor. Then, the optical fibers with the gratings were inserted in the injection mold molding and sequent were made a few injection tests, each one with approximately 40 molding cycles. The results from the experiments were very similar and indicate that the sensors detect maximum values of temperature circa 57 °C. In each molding cycle the temperature variations were practically constant and were about 2 or 3 °C, depending on the sensor in use. Before the molding tests, a numeric simulation was made using software Autodesk Moldflow Synergy 2012. This was made to preview the thermal cycle behaviors and also to determinate the values of some particular input operational parameters for the injection molding machine. This technology based on Brag gratings is unique, because it allows the provision of numerous temperature sensors along a single optical fiber, thus occupying a very small volume. These advantages combined with the excellent resolution in the data acquisition and the quick response to thermal impulses make the FBG sensors an alternative to be taken in good advice for future investigations or tasks applied to the thermal field.
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Jacobsson, Fredrik. "DPSK modulation format for optical communication using FBG demodulator." Thesis, Linköping University, Department of Science and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2307.
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The task of the project was to evaluate a differential phase shift keying demodulation technique by replacing a Mach-Zehnder interferometer receiver with an optical filter (Fiber Bragg Grating). Computer simulations were made with single optical transmission, multi channel systems and transmission with combined angle/intensity modulated optical signals. The simulations showed good results at both 10 and 40 Gbit/s. Laboratory experiments were made at 10 Gbit/s to verify the simulation results. It was found that the demodulation technique worked, but not with satisfactory experimental results. The work was performed at Eindhoven University of Technology, Holland, within the framework of the STOLAS project at the department of Electro-optical communication.
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Parker, Steven W. "FBS free culture of porcine umbilical cord matrix cells." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2319.
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Abeywickrema, Haburugala Vithanage Ujitha A. "Behavior Of Linearly Polarized (LP) Modes in Fibers Containing Bragg Gratings in the Wide Temperature Range." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1313801169.
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Narayanan, Madhavan. "Study of photoinduced electron transfer in fluorescent nucleobase analogues (FBAs) and DNA photolyase." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/119151.
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ChemistryPh.D.
Photoinduced electron transfer (PET) plays a crucial role in a wide array of biological pathways. These electron transfer reactions happen from or to the excited state of a chromophore upon absorption of light. Hence understanding the properties of excited states is necessary in elucidating the details of such pathways. The work presented in this thesis deals with PET in two systems: Fluorescent Nucleobase Analogues (FBAs) and DNA photolyase. The introductory chapter (Chapter 1) presents some background information about the two systems and sets up the stage for the reasoning behind the problems addressed in this thesis. FBAs are fluorescent analogues of naturally occurring, weakly fluorescent native nucleic acid bases. When incorporated into single stranded (ss) or double stranded (ds) DNA, the FBA fluorescence is significantly quenched. PET has been implicated to be the cause for the observed quenching. Here we have presented our attempt to correlate the quenching behavior of free FBA: nucleic acid monophosphate (NMP) pairs with the free energies associated with excited state electron transfer delta GET. Based on the delta GET values, we have tried to assign the direction of electron transfer. The quenching behavior of the FBA:NMP pairs were studied through Stern-Volmer (SV) quenching and time-resolved fluorescence studies. The above described analysis has been applied on FBAs: 4-amino-6-methyl-8-(2'-deoxy-beta-D-ribofuranosyl)-7(8H)-pteridone (6MAP), 4-amino - 2, 6 - dimethyl - 8 - (2'-deoxy-beta-d-ribofuranosyl) -7(8H) - pteridone (DMAP), 3-methyl-8-(2'-deoxy-beta-D-ribofuranosyl) isoxanthopterin (3MI) and 6-Methyl-8-(2'-deoxy-β-D-ribofuranosyl) isoxanthopterin (6MI) (Chapter 3), 2-Aminopurine (2AP) (Chapter 4), 8-Vinyl Adenosine (8VA) (Chapter 5). The final part of this thesis (Chapter 6) is on understanding the mechanistic details of a DNA repair process that is due to photoinduced electron transfer in DNA photolyase, a flavoprotein. Before the electron reaches the damaged site in the DNA, the initial electron acceptor in this repair process has been speculated to be the adenine of the flavin adenine dinucleotide (FAD). We have tested this hypothesis by measuring and comparing the various kinetic parameters associated with this process by reconstituting into apo-photolyase the natural cofactor of photolyase (FAD) and an adenine modified flavin (Etheno FAD, epsilon FAD).
Temple University--Theses
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Petermann, Ann Britt [Verfasser]. "Optische Sensorsysteme auf Polymerbasis : neuartige FBG- und WGM-Strukturen / Ann Britt Petermann." Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/113716400X/34.
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Perazzini, Matteo. "Evaluation of FBG strain sensor reliability through analytical, numerical and experimental results." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22947/.
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The fiber Bragg grating (FBG) sensor is one of the most suitable sensors for structural health monitoring (SHM) of aircraft structures. In principle, the FBG, with adequate sampling and signal processing techniques, is usually more accurate than classical electrical resistive strain gauge. However, since the most common installation method is surface bonding, some significative differences between the strain in the host structure and the one experienced by the fiber may be observed.
The aim of this work is the evaluation of the fiber Bragg grating optical fiber sensor reliability for strain detection in non-uniform strain conditions. A FBG sensor is surface bonded on a rectangular specimen with a centered hole under tensile loading. A multi device method for the strain detection is created with the use of optical fiber, strain gauge and DIC technologies at the same time. In addition, based on microscopic observations, a 3D finite element model of the bonded optical fiber is created to simulate the behavior of the test specimen and to have an insight into the strain transfer between the host material and the optical fiber core. Lastly, being the test specimen a well-known case in literature, the strain is also computed with closed-form expressions. All the experimental, numerical, and analytical results are then compared.
Taking into account the possible sources of error, the comparison shows coherence between the different results. The optical fiber strain sensor reliability is verified through the multiple device method which represents the starting point for future research activities.
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Boudou, Olivier Jean-Christian. "Método para o gerenciamento ágil de projeto com mapas mentais e FBS." Instituto Tecnológico de Aeronáutica, 2012. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2110.
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O sucesso de um projeto de software que utiliza o método ágil Scrum depende fortemente da modelagem e gestão do Product Backlog. O Scrum é um método ágil amplamente utilizado para o desenvolvimento de softwares, que oferece diversos artefatos que auxiliam no gerenciamento de projetos. O Product Backlog é uma lista de itens priorizados pelo dono do projeto, que serão desenvolvidos no sistema. Uma ferramenta auxiliar no gerenciamento de projetos é os mapas mentais que permitem a associação de ideias de forma dinâmica, podendo ser gerados em programas de computador voltados para sua criação que possibilitam alterações e modificações rápidas em seu escopo. O presente trabalho apresenta um método para o gerenciamento e modelagem do Product Backlog por meio do uso de Mapas Mentais e da técnica FBS (Feature Breakdown Structure) dentro da estrutura do Scrum, possibilitando a criação de modelos visuais do Product Backlog e uma melhor gestão dos elementos do modelo durante o projeto. O método proposto apresenta vantagens e limitações que serão exploradas na discussão do estudo de caso que possibilitou a avaliação do método em um projeto de desenvolvimento de um software.
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Wang, Yujuan. "Instrumentação optoeletrônica em hardware: implementação de algoritmos otimizados em sensoriamento a FBG." Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/2073.
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Previous issue date: 2012-12-17Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work presents the development of an FPGA-based optical interrogation system of multiplexed FBG sensors. The Fabry-Perot filter is used to implement the tunable filter method, as a demodulator for FBG sensors. The tuning signal generation for Fabry-Perot filter and the data aquisition are implemented and syncronized em FPGA. Peak-detection algorithms, based on centroid and FIR filter, are implemented em FPGA. The peak displacement detected of FBG reflected spectrum is used to refer sensed elements, such as variation of temperature and refractive index. Besides, other auxiliary digital circuits are implemented for the system configuration, visulization of the detected peak information and the serial communication to monitor entire spectra in computer. All these digital circuits are working on their own duty at the same time, synchronised by the crystal clock of FPGA. The system was used to monitor the fabrication process of an refractive index sensor. The fabricated sensor was tested by measuring the refractive index of water and sucrose. In another experiment, the system was tested by measuring the temperature of a water sample. In addition, a method to calibrate the tuning signal generator is proposed, which can also be employed in other applications that uses DA converters. Finally, the developed system was packaged to facilitate its transportation.
Este trabalho descreve a implementação de um sistema de interrogação óptico para FBGs multiplexadas, com o controle dos processos implementado em FPGA. A interrogação das FBGs é realizada por meio do método de filtro sintonizável, com o uso de filtro Fabry-Perot. Um FPGA é utilizado para gerar sinal de sintonia para o filtro Fabry-Perot e realizar a leitura do sinal espectral refletido pelas FBGs. Algoritmos de detecção de pico (centroide e filtro FIR) foram implementados no FPGA para processar os sinais refletidos por cada FBG, com o objetivo de inferir as propriedades sensoreadas, como variação de temperatura ou índice de refração. Além destes circuitos digitais, são implementados outros circuitos digitais para a configuração do sistema, para a visualização do pico detectado do sinal espectral e para o monitoramento do espectro inteiro via comunicação serial. Todos circuitos cumprem a própria função paralelamente em virtude do paralelismo do FPGA, sincronizado pelo clock do oscilador cristal do FPGA. O sistema desenvolvido foi utilizado no monitoramento do processo de fabricação de sensor de índice de refração e então na leitura do índice de refração de amostras de sacarose e água. O sistema também foi utilizado para a leitura da temperatura de amostras de água, onde foi estimada a sensibilidade e a resolução do sistema. Também foi proposto um método para a calibração do sistema, que pode ser utilizado também em outros trabalhos. O sistema final foi colocado em uma maleta para facilitar o seu transporte para o local de uso.
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Zhang, Po. "High-resolution Photon Counting OTDR based Interrogation of Multiplexing Broadband FBG Sensors." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11064.
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Fiber-optic Bragg grating (FBG) sensors are a very attractive technology for the measurement of strain and temperature. They have many advantages over conventional sensors in sensing applications such as sensitivity, immunity to electromagnetic interferences,large bandwidths,capability of remote operation and the potential power to sense micro strain at high temperature. They can be directly embedded into many structures such as concrete to evaluate the material deformation.
FBGs are fabricated by photo-inscribing through a phase mask technology on a photosensitive fiber. A periodic refractive index is formed in the fiber core, introducing a reflection at the Bragg wavelength. Since the FBG is characterized by a low insertion loss and controllable reflectance, it has the potential to be multiplexed in very large numbers.
The major purpose of this dissertation research is to develop an innovative, high- resolution fiber Bragg grating sensing system using photon-counting optical time domain reflectometry (pc-OTDR) based multiplexing technology. The system uses a Fresnel reflection OTDR with a zero deadzone to detect FBG sensors, which improves both the system detection ability and spatial resolution.
A low reflectance FBG with broad bandwidth has been developed that is appropriate for the pc-OTDR measurement. Hundred of multiplexed sensors have been implemented in this system. Two theoretical analyses and preliminary results are presented. The greatest advantage of the system is to increase the maximum multiplexing sensor number to one thousand within a short fiber range.
Self-referencing demodulation is necessary to eliminate multiplexed system noise caused by the source power fluctuation and fiber bending effects. A referencing FBG with a different wavelength from the sensing FBG has to be introduced to achieve compensation of disturbances in the measurement. The spectral properties of the FBGs and the combination of WDM/TDM are also discussed to evaluate multiplexing sensor performance. The sensor crosstalk and other noise performances are assessed to evaluate the possibility of large scale multiplexing.Ph. D.
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Triana, Infante Cristian Andrés. "Enoding optial FBG sensors to enhance the capacity of optial sensing systems." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/114824.
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Esta tesis investiga la aplicación de conceptos de codificación al diseño de sensores ópticos basados en redes de difracción de Bragg de Bragg (FBG). Específicamente, se presenta el diseño, la caracterización y la validación experimental de dispositivos de detección codificados personalizados que se pueden diseñar y fabricar como dispositivos FBG súper estructurados (SSFBG).
El objetivo de esta tesis es mejorar la capacidad y el rendimiento general de los sistemas de detección óptica basados en sensores FBG convencionales. Para ello, se han propuesto tres metodologías de codificación de dispositivos de detección SSFBG, con el objetivo de dotar a cada sensor con información adicional útil para la identificación de cada sensor incluso en condiciones de superposición. Un sensor codificado basado en FBGs es una estructura FBG cuya forma se ha adaptado a una palabra-código ortogonal, de tal manera que su longitud de onda central se puede distinguir inequívocamente de otras señales en el espectro.
El diseño de los sensores SSFBG codificados se realiza modificando el espectro de reflexión de dispositivos FBG multibanda, esto se logra traduciendo las palabras-código ortogonales en los términos de amplitud y fase de los sensores FBG.
La codificación en amplitud de los sensores SSFBG consiste en traducir las palabras-código \textit{"Optical Orthogonal Codewords"} (OOC), desarrolladas para sistemas de comunicaciones de acceso múltiple por división de código óptico (OCDMA), en el patrón de reflexión de los dispositivos.
La codificación en amplitud y fase se ha propuesto mediante dos enfoques diferentes: en el primero, palabras-código de amplitud y fase personalizadas ($ a_ {k} $, $ f_ {k} $) fueron diseñadas específicamente para exhibir un comportamiento ortogonal obtenido por la combinación de dos palabras-código. La técnica de interrogación basada en una fuente dual sintonizable fue específicamente diseñada para recuperar la medición diferencial de los sensores y decodificar efectivamente su información. El segundo enfoque utiliza las secuencias \textit{"Discrete Prolate Spheroidal Sequences"} (DPSS), que son secuencias mutuamente ortogonales desarrolladas para sistemas de comunicaciones. Se demostró el uso de estas estructuras como elementos de detección ortogonales con patrones específicos de fase y amplitud.
La fabricación y validación experimental de los dispositivos SSFBG propuestos se realizaron para demostrar el rendimiento de los sensores inclusive en condiciones de superposición espectral. La longitud de onda central de los sensores se recupera con éxito en las tres metodologías, además, el error del sistema de detección se caracterizó en términos de los parámetros de diseño.Esta tesi investiga l'aplicació de conceptes de codificació al disseny de sensors òptics basats en xarxes de difracció de Bragg de Bragg (FBG) . Específicament, es presenta el disseny, la caracterització i la validació experimental de dispositius de detecció codificats personalitzats que es poden dissenyar i fabricar com a dispositius FBG súper estructurats (SSFBG) . L'objectiu d'esta tesi és millorar la capacitat i el rendiment general dels sistemes de detecció òptica basats en sensors FBG convencionals. Per a això, s'han proposat tres metodologies de codificació de dispositius de detecció SSFBG, amb l'objectiu de dotar a cada sensor amb informació addicional útil per a la identificació de cada sensor inclús en condicions de superposició. Un sensor codificat basat en FBGs és una estructura FBG la forma de la qual s'ha adaptat a una paraula-codi ortogonal, de tal manera que la seua longitud d'ona central es pot distingir inequívocament d'altres senyals en l'espectre. El disseny dels sensors SSFBG codificats es realitza modificant l'espectre de reflexió de dispositius FBG multibanda, açò s'aconseguix traduint les paraules-codi ortogonals en els termes d'amplitud i fase dels sensors FBG. La codificació en amplitud dels sensors SSFBG consistix a traduir les paraules-codi extit \textit{"Optical Orthogonal Codewords"} (OOC) , desenrotllades per a sistemes de comunicacions d'accés múltiple per divisió de codi òptic (OCDMA) , en el patró de reflexió dels dispositius. La codificació en amplitud i phase s'ha proposat per mitjà de dos enfocaments diferents: en el primer, paraules-codi d'amplitud i fase personalitzades ($ a_ {k} $, $ f_ {k} $) van ser dissenyades específicament per a exhibir un comportament ortogonal obtingut per la combinació de dos paraules-codi. La tècnica d'interrogació basada en una font dual sintonizable va ser específicament dissenyada per a recuperar el mesurament diferencial dels sensors i descodificar efectivament la seua informació. El segon enfocament utilitza les seqüències \textit{"Discrete Prolate Spheroidal Sequences"} (DPSS), que són seqüències mútuament ortogonals desenrotllades per a sistemes de comunicacions. Es va demostrar l'ús d'estes estructures com a elements de detecció ortogonals amb patrons específics de fase i amplitud. La fabricació i la validació experimental dels dispositius SSFBG proposats es van realitzar per a demostrar el rendiment dels sensors inclusivament en condicions de superposició espectral. La longitud d'ona central dels sensors es recupera amb èxit en les tres metodologies, a més, l'error del sistema de detecció es va caracteritzar en termes dels paràmetres de disseny.
This thesis investigates the application of encoding concepts to the design of optical sensors based on fiber Bragg grating (FBG) devices. Specifically, we present the design, characterization and experimental validation of custom encoded sensing devices that can be designed and manufactured as super-structured FBG (SSFBG) devices. The aim of this thesis is to enhance the capacity and the overall performance of the optical sensing systems based on conventional FBG sensors. To do so, three encoding methodologies of SSFBG sensing devices have been proposed, aiming to endow each sensor with additional information useful to identify each sensor even under overlapping conditions. An encoded FBG-based sensor is a FBG structure whose shape has been tailored after an orthogonal codeword in such a way that their central wavelength can be distinguished unequivocally from other signals in the spectrum. The design of encoded SSFBG sensors is performed by modifying the reflection spectrum of multi-band FBG devices, this is achieved by translating orthogonal codewords into the amplitude and phase terms of the FBG sensors. Amplitude encoding of SSFBG sensors consists in translating the binary optical orthogonal codewords (OOCs), developed for optical-code division multiple-access (OCDMA) communications systems, into the reflection pattern of the devices. Amplitude $\&$ phase encoding has been proposed in two different approaches: in the first one, custom amplitude and phase codewords ($a_{k}$, $f_{k}$) were specifically devised to exhibit orthogonal behavior by combining the two codewords. The dual-wavelength tunable interrogation technique was also specifically designed to retrieve the differential measurement of the sensors and effectively decode their information. The second approach uses the discrete prolate spheroidal sequences (DPSS), which are mutually orthogonal sequences developed for communications systems. We demonstrated the use of this structures as orthogonal sensing elements with definite phase and amplitude patterns. The manufacturing and experimental validation of the proposed SSFBG devices were carried out to prove the overlap-proof performance of the devices. The central wavelength of the sensors is successfully retrieved in the three methodologies, additionally, the error of the sensing system was characterized in terms of the design parameters.
Triana Infante, CA. (2018). Enoding optial FBG sensors to enhance the capacity of optial sensing systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/114824
TESIS
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Deng, Fodan. "Corrosion Risk Assessment System For Coated Pipeline System." Diss., North Dakota State University, 2018. https://hdl.handle.net/10365/31713.
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Steel is widely used as building material for large-scale structures, such as oil and gas pipelines, due to its high strength-to-weight ratio. However, corrosion attack has been long recognized as one of the major reasons of steel pipeline degradation and brings great threat to safety in normal operation of structure. To mitigate the corrosion attacks, coatings are generally applied to protect steel pipelines against corrosion and improve durability of the associated structures for longer service life. Although have higher corrosion resistance, coated pipelines will still get corroded in a long run, as coatings may subject to damages such as cracks. Cracks on coatings could lower the effectiveness of protection for associated structures. Timely updates of up-to-date corrosion rate, corrosion location, and coating conditions to the pipeline risk management model and prompt repairs on these damaged coatings would significantly improve the reliability of protected structures against deterioration and failure. In this study, a corrosion risk analysis system is developed to detect and locate the corrosion induced coating cracks on coated steel using embedded fiber Bragg grating (FBG) sensors. The coatings investigated include high velocity oxygen fuel (HVOF) thermal sprayed Al-Bronze coating, wire arc sprayed Al-Zn coating, and soft coating. Theoretical models of corrosion risk assessment system were carried out followed by systematic laboratory experiments, which shows that the developed system can quantitatively detect corrosion rate, corrosion propagations, and accurately locate the cracks initialized in the coating in real time. This real-time corrosion information can be integrated into pipeline risk management model to optimize the corrosion related risk analysis for resource allocation. To place the sensing units of the system in the most needed locations along the huge pipeline systems for an effective corrosion risk assessment, an example case study is conducted in this study to show how to locate the most critical sensor placement locations along the pipeline using worst case oil and gas discharge analysis. Further applications of the developed system can be integrated with pipeline management system for better maintenance resource allocations.USDOT-PHMSA
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Owens, Ashby. "FBOs in Central America: A Critique of Power, Religion and Social Development in Maurice Echeverría’s Diccionario esotérico." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/33244.
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Latin American literature has a rich tradition of translating recreated realities and social commentaries into fictional works. In Central America, especially in Guatemala, El Salvador, and Nicaragua, these commentaries often speak to the plight of the people and the unjust actions of many governments during and after their still fresh civil wars. One Guatemalan author, Maurice Echeverría, stays within the broader trajectory of Central American literature with his novel Diccionario esotérico by creating a fictional work that speaks to a reality and asserts social commentary. This text differs from the corpus, though, by moving beyond the war and the postwar eras to a very current and prominent reality. This novel, which presents a critique of abuses of power in all of their manifestations, gives way to a striking commentary on evangelical organizations. This study will focus on extrapolating this critique to an actual evangelical organization working in Central America, thereby drawing connections between Echeverría’s critical/theological stance and real systems of power.Master of Arts
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Simonet, Vincent. "Inférence de flots d'information pour ML : formalisation et implantation." Paris 7, 2004. http://www.theses.fr/2004PA077167.
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Chagas, Adalberto Francisco. "Influência da taxa de recirculação de lodo no processo de nitrificação em sistema de FBAS precedido de reator UASB." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-13122006-162435/.
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Esta pesquisa teve o objetivo de avaliar o pós-tratamento de um Reator UASB com Filtro Biológico Aerado Submerso, no intuito de verificar sua eficácia na nitrificação, submetendo o mesmo a diferentes taxas de recirculação do lodo do decantador final para a entrada do FBAS. A necessidade do pós-tratamento, deve-se ao fato do efluente do reator UASB, mesmo tendo uma boa eficiência na remoção de matéria orgânica, seu efluente não atende a Legislação ambiental brasileira, logo, o pós-tratamento tem o principal papel de completar a remoção de matéria orgânica, e também efetuar a remoção de nitrogênio amoniacal, que de acordo com a Resolução CONAMA Nº 357, de 17 de março de 2005, o padrão de lançamento é de até 20 mgN/L. Esse estudo foi desenvolvido em unidade de escala piloto, em três regimes distintos de operação, situada no Centro Tecnológico de Hidráulica ? CTH, constituída por um FBAS com um volume útil de 605 L, seguido de decantador, tratando o efluente de um reator UASB de 25 m3. Os três regimes de operação tiveram tempo de duração de 75, 80 e 54 dias, respectivamente, com vazões de alimentação de 500 L/h nos dois primeiros regimes e 200 L/h no regime 3. As taxas de recirculação foram respectivamente 0,2, 0,4 e 0,8, para os regimes 1, 2 e 3. Esses três regimes de operação apresentaram as seguintes taxas de aplicação superficial, respectivamente: DQO (35, 40 e 16 g DQO/m2.dia); DBO (16, 14 e 7 g DBO/m2.dia) e NKT (8,8, 8,7 e 3,1 g NKT/m2.dia). Foram realizadas análises de DBO, DQO, sólidos em suspensão, nitrogênio amoniacal e Kjeldahl, nitrito, nitrato e alcalinidade, onde o regime de operação 3 apresentou os melhores resultados, produzindo um efluente final com as seguintes concentrações médias: 78 mg/L (DQO), 28 mg/L (DBO), 27 mg/L (SST), 12 mg/L (NKT), 10 mg/L (NH3/NH4 +) e 23,4 mg/L (NO3 -). As eficiências de remoção observadas foram: 68% (DQO), 76% (DBO), 79% (SST), 75% (NKT) e 75% (NH3/NH4 +).This study aimed at to evaluate the post-treatment of UASB reactor with aerated submerged biological filter, with the objective of verifying your effectiveness in the nitrification process, submitting it to different sludge recirculation rates from the final settling tank to the entrance of FBAS. The necessity of the post-treatment is due to the fact of the UASB reactor effluent, although tends a good efficiency in the removal of organic matter, it doesn't to meet the standards of Brazilian environmental legislation, therefore, the post-treatment has the main paper of completing the organic matter removal, and also to ammonia nitrogen removal, that in agreement with the Resolution CONAMA N. 357, of march 17, 2005, the release pattern for this parameter is 20 mgN/L. This study was developed in a pilot plant with three different operational regimes, located in ?Centro Tecnológico de Hidráulica ? CTH?, constituted by a FBAS with an useful volume at 605 L, following by settling tank, treating the effluent from 25 m3 UASB reactor. The three operation regimes had time of duration of 75, 80 and 54 days, respectively, with feeding flows at 500 L/hour in the first two regimes and 200 L/hour in the regime 3. The sludge recirculation rate were 0,2, 0,4 and 0,8, for the regimes 1, 2 and 3, respectively. The three operation regimes introduced these superficial aplication rates, respectively: COD (35, 40 and 16 g COD/m2.day); BOD (16, 14 and 7 g BOD/m2.day) and NKT (8,8, 8,7 and 3,1 g NKT/m2.day). Analyses of parameters were accomplished as BOD, COD, solids in suspension, ammonia nitrogen and total Kjeldahl nitrogen, nitrite, nitrate and alkalinity, where the operation regime 3 presented the best results, producing a final effluent with these average concentrations: 78 mg/L (COD), 28 mg/L (BOD), 27 mg/L (TSS), 12 mg/L (NKT), 10 mg/L (NH3/NH4 +) and 23,4 mg/L (NO3 -). The observed efficiency removal were: 68% (COD), 76% (BOD), 79% (TSS), 75% (NKT) and 75% (NH3/NH4 +).
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Arceno, Mark Anthony. "On Consuming and Constructing Material and Symbolic Culture: An Anthropology of Pictorial Representations of Food-Based Dietary Guidelines (FBDGs)." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449764020.
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Khalil, Mostafa Khalil. "The contribution of Islamic-based CSOs to poverty reduction in Egypt : the mechanisms, the politics and the lessons." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/the-contribution-of-islamicbased-csos-to-poverty-reduction-in-egypt-the-mechanisms-the-politics-and-the-lessons(85b282bf-6129-460a-9a6c-a0ea6083a55e).html.
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This thesis provides a critical analysis of how Islamic-based Civil Society Organisations (IBCSOs) contribute to poverty reduction in Egypt, through a qualitative study of four Civil Society Organisations (CSOs). The thesis closely examines case study IBCSOs’ organisational structures, their activities and the values that shape their conceptualisation of poverty. It reveals the similarities between IBCSOs’ poverty reduction work and official social protection, and discusses how their approaches to poverty reduction can be understood in terms of the various discourses justifying social protection (risks, rights and needs). The thesis also uses these case studies to examine the validity of Faith-Based Organisations (FBOs) as vehicles for poverty reduction and social protection. Finally, it discusses the relationship between these organisations’ poverty reduction activities and political mobilisation through an examination of the role they played in the recent political rise of the Islamist movement in Egypt, as well as the impact of recent political developments on their operations. A key purpose of this critical investigation of IBCSOs' approaches to poverty reduction is to explore more broadly their wider implications for development theory and practice by assessing whether they can contribute to existing knowledge on the means of civil society’s contribution to poverty reduction and development.
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Martinez, Guadalupe Federico. "Giving It the Old College Try: Understanding Degree Commitment among Division I FBS NFL Aspirants." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/228181.
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Building on sociological studies regarding college choice and persistence, this qualitative study investigates the college and post college experiences of 15 current students with NFL aspirations and 13 former students who held NFL aspirations, all from Division I Football Bowl Series (FBS) programs. A phenomenological design is implemented to explore participants' lived experiences, and awareness of their educational and occupational options. Deil-Amen and Tevis' (2010) Circumscribed Agency frames this study and provides a lens for examining the college choice and departure process. The role of the student exerting agency as circumscribed by context, habitus, and self-efficacy is emphasized with self-perceptions being essential in the process of enacting individual behavior and decisions. Perna's (2006) conceptual college choice model is made up of four contextual layers and is used to further explain students' college choice behaviors. Findings are consistent with Bowen and Schulman (2001) in that students' college decisions are driven by their athletic pursuits. This study also addresses persistence for this group of students. Tinto's (1993) theory on departure is used as a platform from which to examine commitment and social integration. Traditionally, degree commitment has been measured as strong or which severely limits our understanding of persistence. Findings reveal degree commitment to be fluid and contingent upon perceived occupational options, health status, and year in college. The majority of current students express commitment to degree attainment as a priority. However, further investigation reveals degree commitment to exist without a specific time frame set by students. This adds a time dimension to our understanding of degree commitment. This study further extends Tinto's concept of commitment with evidence of two competing goal commitments: degree and occupational. Decisions to leave college early for the NFL are driven by participants' self-perception of their athletic abilities despite where they are on the team's talent roster. This decision is further shaped by their college community integration consisting of teammates, coaches, and the NFL. Former students who stopped out of college reveal unanticipated challenges with re-entry into college. However, in contemplating a return to complete their bachelor’s degree, stop outs articulate a renewed sense of energy and degree commitment given a change in their occupational trajectory and situated context.
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Wang, Lei. "Cloning and characterization of a novel oocyte-specific gene Fbos encoding an F-Box protein in rainbow trout (Oncorhynchus mykiss)." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10786.
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Thesis (M.S.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains vii, 51 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 46-51).
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Fussangel, Kathrin. "Subjektive Theorien von Lehrkräften zur Kooperation : eine Analyse der Zusammenarbeit von Lehrerinnen und Lehrern in Lerngemeinschaften." kostenfrei, 2008. http://elpub.bib.uni-wuppertal.de/edocs/dokumente/fbg/paedagogik/diss2008/fussangel.
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Achterberg, Susanne. "Intime Nachrichten : die geschlechtliche und generationale Ordnung in sexuellen Aufklärungsratgebern für Jugendliche." kostenfrei, 2007. http://elpub.bib.uni-wuppertal.de/edocs/dokumente/fbg/soziologie/diss2008/achterberg.
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Seo, Bo-Kyung. "Ereignis- und bewegungskorrelierte evozierte Potentiale und kognitive Leistung bei der Aufmerksamkeitsdefizit-, Hyperaktivitätsstörung (ADHS) im Erwachsenenalter." kostenfrei, 2008. http://elpub.bib.uni-wuppertal.de/edocs/dokumente/fbg/psychologie/diss2008/seo.
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SANTOS, Adam Dreyton Ferreira dos. "Proposta de gerenciamento de dados para monitoramento de saúde estrutural utilizando redes de sensores ópticos FBG." Universidade Federal do Pará, 2014. http://repositorio.ufpa.br/jspui/handle/2011/5603.
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CVRD - Companhia Vale do Rio Doce
FAPESPA - Fundação Amazônia de Amparo a Estudos e Pesquisas
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Devido às suas características únicas, redes de sensores ópticos têm encontrado aplicação em muitos campos, como em Engenharia Civil, Engenharia Geotécnica, Aeronáutica, Energia e Indústrias de Petróleo & Gás. Soluções de monitoramento baseadas nessa tecnologia têm se mostrado particularmente rentáveis e podem ser aplicadas às estruturas de grande porte, onde centenas de sensores devem ser implantados para medições a longo prazo de diferentes parâmetros mecânicos e físicos. Sensores baseados em Grades de Bragg em fibra (FBGs) são a solução mais comumente utilizada no Monitoramento de Saúde Estrutural (SHM) e as medições são realizadas por instrumentos especiais conhecidos como interrogadores ópticos. Taxas de aquisição cada vez mais elevadas têm sido possíveis utilizando interrogadores ópticos mais recentes, o que dá origem a um grande volume de dados cuja manipulação, armazenamento, gerenciamento e visualização podem demandar aplicações de software especiais. Este trabalho apresenta duas aplicações de software de tempo real desenvolvidas para esses fins: Interrogator Abstraction (InterAB) e Web-based System (WbS). As inovações neste trabalho incluem a integração, sincronização, independência, segurança, processamento e visualização em tempo real, e persistência de dados ou armazenamento proporcionados pelo trabalho conjunto das aplicações desenvolvidas. Os resultados obtidos durante testes em laboratório e ambiente real demonstraram a eficiência, robustez e flexibilidade desses softwares para diferentes tipos de sensores e interrogadores ópticos, garantindo atomicidade, consistência, isolamento e durabilidade dos dados persistidos pelo InterAB e apresentados pelo WbS.
Due to their unique characteristics, optical sensor networks have found application in many fields, such as in Civil and Geotechnical Engineering, Aeronautics, Energy and Oil & Gas Industries. Monitoring solutions based on this technology have proven particularly cost effective and can be applied to large scale structures where hundreds of sensors must be deployed for long term measurement of different mechanical and physical parameters. Sensors based on Fiber Bragg gratings (FBGs) are the most common solution used in Structural Health Monitoring (SHM) and the measurements are performed by special instruments known as optical interrogators. Acquisition rates increasingly higher have been possible using the latest optical interrogators, which gives rise to a large volume of data whose manipulation, storage, management and visualization can demand special software applications. This work presents two real-time software applications developed for these purposes: Interrogator Abstraction (InterAB) and Web-based System (WbS). The innovations in this work include the integration, synchronization, independence, security, processing and real-time visualization, and data persistence or storage provided by joint work of developed applications. The results obtained during tests in laboratory and real environment demonstrate the efficiency, robustness and flexibility of these softwares for different types of sensors and optical interrogators, ensuring atomicity, consistency, isolation and durability of data persisted by InterAB and displayed by WbS.
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Lammi, Matthew D. "Characterizing High School Students' Systems Thinking in Engineering Design Through the Function-Behavior-Structure (FBS) Framework." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/849.
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The aim of this research study was to examine high school students' systems thinking when engaged in an engineering design challenge. This study included 12 high school students that were paired into teams of two to work through an engineering design challenge. These dyads were given one hour in their classrooms with access to a computer and engineering sketching paper to complete the design. Immediately following the design challenge, the students participated in a post hoc reflective group interview.
The methodology of this study was informed by and derived from cognitive science's verbal protocol analysis. Multiple forms of data were gathered and triangulated for analysis. These forms included audio and video recordings of the design challenge and the interview, computer tracking, and student-generated sketches. The data were coded using Gero's FBS framework. These coded data were analyzed using descriptive statistics. The transitions were further analyzed using measures of centrality. Additionally, qualitative analysis techniques were used to understand and interpret systems and engineering design themes and findings.
Through the qualitative and quantitative analyses, it was shown that the students demonstrated thinking in terms of systems. The results imply that systems thinking can be part of a high school engineering curriculum. The students considered and explored multiple interconnected variables, both technical as well as nontechnical in nature. The students showed further systems thinking by optimizing their design through balancing trade-offs of nonlinear interconnected variables. Sketching played an integral part in the students' design process, as it was used to generate, develop, and communicate their designs. Although many of the students recognized their own lack of drawing abilities, they understood the role sketching played in engineering design. Therefore, graphical visualization through sketching is a skill that educators may want to include in their curricula. The qualitative analysis also shed light on analogical reasoning. The students drew from their personal experience in lieu of professional expertise to better understand and expand their designs. Hence, the implication for educators is to aid the students in using their knowledge, experience, and preexisting schemata to work through an engineering design.
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Salinas, Silvia M. "The Academic and Athletic Experiences of African-american Males in a Division I (Fbs) Football Program." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407844/.
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This study investigated the academic and athletic experiences of African-American males in a Division I football bowl subdivision football program. Critical race theory, identity development model, and social learning model were the theoretical frameworks used as the critical lenses in a qualitative design to examine the participants. The participants’ responses were analyzed and interpreted using thematic analysis. A qualitative research design, which included individual interviews with 10 second year African-American male football players, was used to address this research problem. The goal was to bring together both the psychological and sociological perspectives and to challenge participants to candidly describe their academic and athletic experiences and attitudes toward obtaining an undergraduate degree. Four themes were determined in the data analysis: differential treatment and determining oneself, time management, relationships, and career aspirations. In relation to the theoretical frameworks, the development of self-confidence and knowledge of balancing their academic and athletic schedules was critical for all participants. The sense of feeling different and challenged because of the differences in culture and experience was evident. From this study, university and collegiate athletics administrators may better understand the backgrounds, challenges, and learning needs of this population. As a result, higher education personnel may improve the services they provide these young men in hopes of educating and developing whole persons—physically, emotionally, intellectually, socially, and spiritually—to become well-rounded and functional in contemporary society.
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Colon-Mollfulleda, Wanda I. "Public Issues or Private Concerns: Assessing the Impact of Charitable Choice on Private Donations to Faith-based Organizations." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1208784329.
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Chanadang, Sirichat. "Tolerance testing for cooked porridge made from a sorghum based fortified blended food." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/18829.
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Master of ScienceDepartment of Human Nutrition
Kadri Koppel
Products must be tolerant to many conditions, particularly when those products are prepared by consumers. Consumers may not measure added ingredients, they may add or leave out ingredients specified in recipes, or change cooking and holding times for foods. Fortified blended food (FBFs) are used as a source of nutrition for disaster or famine relief in developing countries and sorghum is looked at as a potential alternative to wheat and corn based products that are currently being used as FBFs. Porridge products are the most common dishes prepared from FBFs with a wide range of solids content, cooking times and variations in added ingredients such as sugar and fruit. This study was intended to evaluate the tolerance to preparation variations for a porridge product made as a FBF intended for food aid. Whole Sorghum Soy Blend (WSSB), a fortified, extruded, ground cooked cereal was selected as the FBF for this study. Descriptive sensory analysis was performed to evaluate the tolerance of porridge products made from variations in ingredients and cooking procedures. In this study, most sensory properties were only marginally affected by variations in ingredients or procedures. However, as expected, large differences occurred in some properties such as thickness when solids content varied or sweetness and fruit flavor when fruit was added. Tolerance testing showed that the sensory properties of WSSB had high tolerance to variations in cooking procedures, a positive aspect for product use and development. This means that the product can be modified during preparation by consumers without having a major impact on most sensory properties.
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Smoleniec, John Stefan. "Preterm fetal behavioural states and the risk of sudden infant death syndrome." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324366.
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Ting, Song. "Expert vs. Novice: Problem Decomposition/Recomposition in Engineering Design." DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/3104.
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The purpose of this research was to investigate the differences of using problem decomposition and problem recomposition among dyads of engineering experts, dyads of engineering seniors, and dyads of engineering freshmen. Fifty participants took part in this study. Ten were engineering design experts, 20 were engineering seniors, and 20 were engineering freshmen. Participants worked in dyads to complete an engineering design challenge within an hour. The entire design process was video and audio recorded. After the design session, members participated in a group interview.
This study used protocol analysis as the methodology. Video and audio data were transcribed, segmented, and coded. Two coding systems including the FBS ontology and “levels of the problem” were used in this study. A series of statistical techniques were used to analyze data. Interview data and participants’ design sketches also worked as supplemental data to help answer the research questions.
By analyzing the quantitative and qualitative data, it was found that students used less problem decomposition and problem recomposoition than engineer experts in engineering design. This result implies that engineering education should place more importance on teaching problem decomposition and problem recomposition. Students were found to spend less cognitive effort when considering the problem as a whole and interactions between subsystems than engineer experts. In addition, students were also found to spend more cognitive effort when considering details of subsystems. These results showed that students tended to use dept-first decomposition and experts tended to use breadth-first decomposition in engineering design. The use of Function (F), Behavior (B), and Structure (S) among engineering experts, engineering seniors, and engineering freshmen was compared on three levels. Level 1 represents designers consider the problem as an integral whole, Level 2 represents designers consider interactions between subsystems, and Level 3 represents designers consider details of subsystems. The results showed that students used more S on Level 1 and 3 but they used less F on Level 1 than engineering experts. The results imply that engineering curriculum should improve the teaching of problem definition in engineering design because students need to understand the problem before solving it.
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Bond, Justin Matthew. "Status Monitoring Of Inflatables By Accurate Shape Sensing." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/677.
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The use of inflatable structures in aerospace applications is becoming increasingly widespread. In order to monitor the inflation status and overall health of these inflatables, an accurate means of shape sensing is required. To this end, we investigated two existing methods for measuring simple curvature, or curvature in one-dimension. The first method utilizes a pair of strain sensing Fiber Bragg Gratings (FBGs) separated by a known distance; dividing the difference in strain by the separation distance yields an experimental value for the one-dimensional curvature at a point. The second method makes use of conductive ink-based flex sensors, which give a variable resistance based on curvature. We used the latter was in a design for a Curvature-Based Inflation Controller (CBIC). While the controller successfully inflated a test body, its overall utility is limited by the simplicity of its sensors. To improve the shape sensing capabilities of the controller, we investigated the use of FBGs in a multidimensional array.
We fabricated a curvature-sensing FBG pair on an inflatable membrane and tested its accuracy as the membrane was shaped into a known radius of curvature. This work reports on the assembly of three such curvature-sensing FBG pairs into a two-dimensional Curvature-Sensing Rosette (CSR). The goal is to use this rosette to measure the curvature of a surface in multiple directions at a single point. A 3-D printed surface with saddle geometry was used to calibrate the curvature-sensing rosette. Presented will be methods of extracting values for the tensor of curvature for the surface at a point using the curvature-sensing rosette, along with experimental verification. This essentially defines the local geometry about the rosette, measured in real time. By employing an array of such rosettes across the surface of an inflatable structure, the local curvature of the inflatable could be known at every point. Combining these curvature measurements can yield an accurate depiction of the global geometry. Thus, the inflation status of the inflatable space structure could be monitored in real time.
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Vitikainen, Rudelene Nanette. "Communicating Faith-Identity in Development: A case study of three Faith-Based Organisations (FBOs) in the Mindanao Island of Southern Philippines." Thesis, Malmö universitet, Fakulteten för kultur och samhälle (KS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22745.
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This research paper is a case study on the identity of three Faith-Based Organisations (FBOs) located in the Mindanao Island of Southern Philippines. The empirical data was collected employing qualitative semi-structured interviews through virtual interactions. The research captures the journey of the three local FBOs as they continue to sustain their identity amidst the changes in the development world where they function. Identity is a complex issue, especially when FBOs have to experience the pressure to conform to how the world thinks who they are. So what does faith identity mean to these FBOs? How is this identity communicated in practice?The aim of this research is to acquire a better understanding of these FBOs; their faith- identity and its values; and how faith provides direction for actions which shape and characterise these organisations. Moreover, considerations were taken that faith is manifested in different ways. In studying these FBOs, the researcher was provided with another perspective on why FBOs held on to their identity regardless of the constant pressure to conform to the changing world and the opportunities the changing world has to offer. Moreover, to acquire knowledge on the importance of their identity helps to bridge communication gaps among the many actors in development and to know what to expect in development partnership.According to the modernists, religion will disappear. For the international development actors, religion will be less important as the communities modernise. However, faith is still significant to the FBOs in this research. Faith is not an add-on to the development work they do. Faith is the reason for their existence. For these FBOs, faith-identity means their development activities are inspired and guided by God to have compassion for the poor and marginalised people. For them, faith is communicated in practice by providing genuine care and by being inclusive in their development commitments.
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Colpo, Fabiano. "Residual stress characterization in a single fibre composite specimen by using FBG sensor and the OLCR technique /." [S.l.] : [s.n.], 2006. http://library.epfl.ch/theses/?nr=3533.
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