Devido ao processo de urbanização sem planejamento adequado, as cidades costeiras sofrem com as inundações e erosão das praias com a elevação do nível do mar e ação de ondas. Entre as estruturas mais utilizadas para proteção de praias destacam-se os quebra-mares segmentados. Para estudar e prever as respostas praiais à presença destas estruturas, podem ser empregados modelos numéricos, capazes de calcular os processos complexos deste ambiente. Este trabalho teve como objetivo o estudo da resposta hidrodinâmica e sedimentar de uma praia com a implantação de quebra-mares segmentados. O modelo hidrodinâmico utilizado é o MIKE21FM acoplado ao modelo de ondas SW e sedimentos ST e SM. Primeiramente, foram impostas condições hidrodinâmicas simplificadas e diferentes arranjos de quebra-mares segmentados. As áreas erodidas e acrescidas após a implantação da obra foram comparadas e priorizou-se minimizar a área erodida. Em seguida, foram considerados os cenários de condições hidrodinâmicas variadas com uma das estruturas. Os resultados são apresentados em termos de altura significativa e potência de onda para 18 casos de condições hidrodinâmicas constantes, as quais foram feitas variar em nível e características da onda. Para a condição hidrodinâmica mais crítica, obteve-se uma redução de 0,4m da altura significativa média e 2kW/m da potência média da onda. Através desses resultados é possível aquilatar a proteção da região da praia da ação das ondas após a implantação da estrutura. Além disso, foram feitas duas simulações com 3 a 4 meses de evolução do fundo em condições hidrodinâmicas reais, com o intuito de apresentar qualitativamente as áreas de erosão e acreção do fundo da praia. Resultados mostraram que a deriva litorânea local tem direção sudeste, para a Ponta da Praia. Foi observada sedimentação no tardoz dos segmentos e na região de sombra e erosão nas áreas entre segmentos e a frente destes. Com isso, este trabalho colabora com o gerenciamento costeiro na região de Santos, apresentando o início de uma pesquisa para uma possível solução para os problemas de inundação e erosão da região da Ponta da Praia. / Erosion and flooding are common problems faced by coastal cities as a consequence of urbanization process without previous planning, with the sea level rise and the wave action. In order to mitigate these problems, shoreline protection structures are constructed along the coastlines, such as segmented breakwaters. Numerical models are tools frequently used in these studies because of its capacity of calculating the complex processes on a coastal environment. This study aim is to present a study based on the hydrodynamic and sediment transport response of a curved beach to the presence of segmented emerged breakwaters. The numerical model used is the MIKE21FM coupled with wave spectral and sediment transport modules. Firstly, constant boundary conditions were applied for the period of one year in order to understand the response of the beach to five different designs of coastal breakwaters. One of these structures were chosen to continue the study based on the area and length of the beach eroded and accreted. Secondly, eighteen different scenarios of wave and water level were applied to the selected structure and the protection of wave action were compared and analyzed. To the most critical hydrodynamic condition, the structure reduced 0,4 m of the mean significant wave height and 2 kW/m of the mean wave power. Finally, two real hydrodynamic conditions were applied and the sediment transport was qualitatively analyzed. Results show that the littoral drift in the studied area is directed to the southeast end of the beach, straight to the Ponta da Praia, without the spur breakwater, the sediment would end inside the navigation channel. Besides that, it shows the sedimentation and erosion patterns at the beach generated by the presence of the breakwater. The sediment is accumulated at the shadow area and at the lee, whereas the erosion is located at the front of the breakwaters and between the segments, as expected. Therefore, this study collaborates with the management of Santos, by presenting herewith a possible solution for the inundation and erosion problems of this area.

The ability to detect and quantify presence and concentration of unknown gasses is sought for applications ranging from environmental monitoring to medical analysis. Metal oxide based chemical sensing technology currently exists but the ability to provide a compositional gas breakdown reliably within a short time frame is not readily available. A very small sensor that can differentially identify the type and concentration of a gas is required. Novel methods of creating low cost and easily tuned one and two-dimensional gas sensing elements are explored. Tungsten trioxide has been thoroughly documented as an electrochromic coating, but highly sensitive WO3 elements with beam and nanowire structures have yet to be explored. Research of WO3 as a gas sensor encompasses three major components: A suitable sensing chamber with accurate analyte gas flow control and temperature control, a reliable method for WO3 deposition, and a high yield fabrication process. This thesis explores all three of these technologies. Chapter two starts with a summary of existing tungsten trioxide fabrication methods. An overview of WO3 processing follows. A comprehensive setup was designed and created to test the gas sensing response of a series of metal oxide based resistive elements through conductimetric analysis. Chapter three provides an in depth account of gas sensor test chamber design and testing. Critical test chamber aspects such as temperature control, precise gas flow control, highly efficient analyte gas switching and ease of use are presented. Chapter four outlines WO3 electrodeposition and the fabrication of beam structures for testing, while chapter five explores the templated electrodeposition of WO3 segments intercalated between gold nanowire segments. Finally, chapter six provides a summary of the research presented in this thesis as well as future directions and options available for further exploration of WO3 gas sensing elements. / Micro-Electro-Mechanical Systems (MEMS) and Nanosystems

The degradation of astronomical images caused by atmospheric turbulence will be much more severe in the next generation of terrestrial telescopes and its compensation will require deformable mirrors with up to tens-of-thousands of actuators. Current designs for these correctors consist of scaling up the proven technologies of flexible optical plates deformed under the out-of-plane action of linear actuators. This approach will lead to an exponential growth of cost with the number of actuators, and in very complex mechanisms. This thesis proposes a new concept of optical correction which is modular, robust, lightweight and low-cost and is based on the bimorph in-plane actuation. The adaptive mirror consists of segmented identical hexagonal bimorph mirrors allowing to indefinitely increase the degree of correction while maintaining the first mechanical resonance at the level of a single segment and showing an increase in price only proportional to the number of segments. Each bimorph segment can be mass-produced by simply screen-printing an array of thin piezoelectric patches onto a silicon wafer resulting in very compact and lightweight modules and at a price essentially independent from the number of actuators. The controlled deformation of a screen-printed bimorph mirror was experimentally achieved with meaningful optical shapes and appropriate amplitudes; its capability for compensating turbulence was evaluated numerically. The generation of continuous surfaces by an assembly of these mirrors was numerically simulated and a demonstrator of concept consisting of 3 segments was constructed.

This dissertation examines the adaptation of Christian refugees from Southern Sudan—primarily Dinkas and mostly educated—to living in Ottawa, Canada, not historically a gateway immigrant city. The discussion is based on sustained observation, documentation and analysis of South Sudanese refugees between 2005 and 2009, including 32 recorded interviews of adults, as well as a focus group held with young adults. It examines the findings through the lenses of social capital, with its focus on trust and reciprocity, and segmented assimilation to study the South Sudanese refugees’ integration through their most important groupings: ethnic, gendered, racial and religious. The study also focuses on the cultural, gender and language dynamics of a nascent South Sudanese-focused congregation and a related East African congregation. The experiences of Anglican and Catholic congregations with Christian Sudanese refugees were also examined. The research suggests that inter-culturally competent ethnic and religious leadership is central to the ability of migrant groups in the Global North to have enough bonding social capital to mediate the adaptation process and to bridge or link to other groups. First-wave, mostly male, educated refugees often have the inter-cultural skills and agency to set up effective organizations, but a continued focus on their region of origin, facilitated by the Internet and cell phones, makes a sustained emphasis on organizational-supported living in Canada difficult. While the values of many Sudanese-born women and their children converge with those of mainstream Canadian society, men living within patriarchal value systems, supported by literal interpretations of Holy Scriptures, face challenges, and the resulting conflicts threaten family cohesion. Both the denominational and the ethnic churches, in supporting new migrants spiritually and socially, are caught between denominational parameters and goals of ethnic identity, culture and values maintenance, made more difficult by the Sudanese not having a common language. The dissertation also begins to analyze the impact for recent African Christian immigrants of a culture that emphasizes individual rights, including the effects of the increasing presence of openly gay leaders in the Canadian but not in the African Church. / Cette dissertation se penche sur l’adaptation des réfugiés chrétiens originaires du Sud du Soudan, en majorité d’ethnie Dinka et scolarisés, vivant à Ottawa, Canada. Les résultats de la recherche sur 5 ans suggèrent qu’une gestion adéquate des dynamiques ethniques et religieuses au niveau interculturel est capitale dans la capacité des groupes de migrants dans les pays développés pour générer suffisamment de capital social et faciliter le processus d’adaptation pour se lier à d’autres groupes. Les églises confessionnelles et les églises ethniques, en aidant les immigrants spirituellement et socialement, sont coincées entre des paramètres confessionnels et des objectifs d’identification ethnique, de maintien de valeurs et de culture, compliqués par l’absence d’une langue commune parmi les Soudanais. Cette dissertation tente aussi d’analyser l’impact pour les immigrants africains de fraîche date, d’une culture qui valorise les droits individuels, y compris l’émergence de chefs de file ouvertement homosexuels dans les églises canadiennes mais non dans les églises africaines. / University of Ottawa

Code-Division Multiple-Access (CDMA) is one of the leading digital wireless communication methods currently employed throughout the world. Third generation (3G) and future wireless CDMA systems are required to provide services to a large number of users where each user sends data burst only occasionally. The preferred approach is packet based CDMA so that many users share the same physical channel simultaneously. In CDMA, each user is assigned a pseudo-random (PN) code sequence. PN codephase synchronization between received signals and a locally generated replica by the receiver is one of the fundamental requirements for successful implementation of any CDMA technique. The customary approach is to start each CDMA packet with a synchronization preamble which consists of PN code without data modulation. Packets with preambles impose overheads for communications in CDMA systems especially for short packets such as mouse-clicks or ATM packets of a few hundred bits. Thus, it becomes desirable to perform PN codephase synchronization using the information-bearing signal without a preamble. This work uses a segmented matched filter (SMF) which is capable of acquiring PN codephase in the presence of data modulation. Hence the preamble can be eliminated, reducing the system overhead. Filter segmentation is also shown to increase the tolerance to Doppler shift and local carrier frequency offset. <p>Computer simulations in MATLAB® were carried out to determine various performance measures of the acquisition system. Substantial improvement in probability of correct codephase detection in the presence of multiple-access interference and data modulation is obtained by accumulating matched filter samples over several code cycles prior to making the codephase decision. Correct detection probabilities exceeding 99% are indicated from simulations with 25 co-users and 10 kHz carrier frequency offset or Doppler shift by accumulating five or more PN code cycles, using maximum selection detection criterion. Analysis and simulation also shows that cyclic accumulation can improve packet throughput by 50% and by as much as 100% under conditions of high offered traffic and Doppler shift for both fixed capacity and infinite capacity systems.

This dissertation examines the adaptation of Christian refugees from Southern Sudan—primarily Dinkas and mostly educated—to living in Ottawa, Canada, not historically a gateway immigrant city. The discussion is based on sustained observation, documentation and analysis of South Sudanese refugees between 2005 and 2009, including 32 recorded interviews of adults, as well as a focus group held with young adults. It examines the findings through the lenses of social capital, with its focus on trust and reciprocity, and segmented assimilation to study the South Sudanese refugees’ integration through their most important groupings: ethnic, gendered, racial and religious. The study also focuses on the cultural, gender and language dynamics of a nascent South Sudanese-focused congregation and a related East African congregation. The experiences of Anglican and Catholic congregations with Christian Sudanese refugees were also examined. The research suggests that inter-culturally competent ethnic and religious leadership is central to the ability of migrant groups in the Global North to have enough bonding social capital to mediate the adaptation process and to bridge or link to other groups. First-wave, mostly male, educated refugees often have the inter-cultural skills and agency to set up effective organizations, but a continued focus on their region of origin, facilitated by the Internet and cell phones, makes a sustained emphasis on organizational-supported living in Canada difficult. While the values of many Sudanese-born women and their children converge with those of mainstream Canadian society, men living within patriarchal value systems, supported by literal interpretations of Holy Scriptures, face challenges, and the resulting conflicts threaten family cohesion. Both the denominational and the ethnic churches, in supporting new migrants spiritually and socially, are caught between denominational parameters and goals of ethnic identity, culture and values maintenance, made more difficult by the Sudanese not having a common language. The dissertation also begins to analyze the impact for recent African Christian immigrants of a culture that emphasizes individual rights, including the effects of the increasing presence of openly gay leaders in the Canadian but not in the African Church. / Cette dissertation se penche sur l’adaptation des réfugiés chrétiens originaires du Sud du Soudan, en majorité d’ethnie Dinka et scolarisés, vivant à Ottawa, Canada. Les résultats de la recherche sur 5 ans suggèrent qu’une gestion adéquate des dynamiques ethniques et religieuses au niveau interculturel est capitale dans la capacité des groupes de migrants dans les pays développés pour générer suffisamment de capital social et faciliter le processus d’adaptation pour se lier à d’autres groupes. Les églises confessionnelles et les églises ethniques, en aidant les immigrants spirituellement et socialement, sont coincées entre des paramètres confessionnels et des objectifs d’identification ethnique, de maintien de valeurs et de culture, compliqués par l’absence d’une langue commune parmi les Soudanais. Cette dissertation tente aussi d’analyser l’impact pour les immigrants africains de fraîche date, d’une culture qui valorise les droits individuels, y compris l’émergence de chefs de file ouvertement homosexuels dans les églises canadiennes mais non dans les églises africaines. / University of Ottawa

Code-Division Multiple-Access (CDMA) is one of the leading digital wireless communication methods currently employed throughout the world. Third generation (3G) and future wireless CDMA systems are required to provide services to a large number of users where each user sends data burst only occasionally. The preferred approach is packet based CDMA so that many users share the same physical channel simultaneously. In CDMA, each user is assigned a pseudo-random (PN) code sequence. PN codephase synchronization between received signals and a locally generated replica by the receiver is one of the fundamental requirements for successful implementation of any CDMA technique. The customary approach is to start each CDMA packet with a synchronization preamble which consists of PN code without data modulation. Packets with preambles impose overheads for communications in CDMA systems especially for short packets such as mouse-clicks or ATM packets of a few hundred bits. Thus, it becomes desirable to perform PN codephase synchronization using the information-bearing signal without a preamble. This work uses a segmented matched filter (SMF) which is capable of acquiring PN codephase in the presence of data modulation. Hence the preamble can be eliminated, reducing the system overhead. Filter segmentation is also shown to increase the tolerance to Doppler shift and local carrier frequency offset. <p>Computer simulations in MATLAB® were carried out to determine various performance measures of the acquisition system. Substantial improvement in probability of correct codephase detection in the presence of multiple-access interference and data modulation is obtained by accumulating matched filter samples over several code cycles prior to making the codephase decision. Correct detection probabilities exceeding 99% are indicated from simulations with 25 co-users and 10 kHz carrier frequency offset or Doppler shift by accumulating five or more PN code cycles, using maximum selection detection criterion. Analysis and simulation also shows that cyclic accumulation can improve packet throughput by 50% and by as much as 100% under conditions of high offered traffic and Doppler shift for both fixed capacity and infinite capacity systems.

Gradient Enhanced Piezoelectric Actuators (GEPAC) are thin piezoelectric plates embedded between two composites layers having different thermal properties. Compared to standard unimorph bending actuators, GEPACs offer superior performances for operations at low frequencies. Potential applications are in the area of multifunctional aircraft skins. In practice, delaminations or debonding within the actuator itself can occur, and it is highly desirable to develop an ultrasonic nondestructive method to monitor the integrity of the actuator in real time. For this study, the composite material is unidirectional Kevlar-epoxy, with fibers oriented at 90 and 0 for the upper and lower layers to achieve different coefficient of thermal expansion. A thin PZT plate is inserted between the two layers, and extended copper foil is used for electrodes on the PZT. The first objective of the research is to demonstrate that, by using segmented electrodes, one can simultaneously launch an ultrasonic pulse (1 MHz) for NDE testing while the actuator is undergoing low frequency actuation (less than 100 Hz). The second objective is to show that the ultrasonic signal can be used to detect damage induced during fatigue testing of the actuator. The third objective is to use the technique to monitor the integrity of a composite plate containing several embedded GEPACs.

Transit ridership analysis has been advancing towards the use of disaggregate spatial and boarding data. This study attempts to improve the understanding of factors influencing transit ridership by estimating/comparing ridership models at the route, the segmented route, and the stop level in the Austin area. Spatial and statistic analysis methods are used in this study. The dependent variable is ridership at the transit route, the segmented route, and the stop level, whereas independent variables consist of traveler characteristics, land use, transit service characteristics, and other contextual factors. Spatial analysis is conducted using Geographic Information System (GIS) to compile data within a quarter-mile buffer from each transit stop, each segregated route, and each route. Linear and semi-log models of ridership are estimated using Statistical Analysis System (SAS). Initial analysis confirms the qualitative understanding that traveler demographics such as population and employment densities, ethnic background, and income significantly affect transit ridership. Land use composition, measured by the shares of single-family homes, multi-family homes, commercial, civic uses, as well as the total area of paved parking, all influence transit use. Service qualities such as headway and transfer opportunities also matter. Sensitivity tests of these factors affecting ridership are carried out to compare model performance among the route, segmented route, and the stop level analyses. It is expected that the study findings will help to better inform transit agencies and local communities in optimizing existing transit operations, planning for new services, and developing transit-friendly environments. Primary data were obtained from the Capital Metropolitan Transit Authority and the Census Bureau, and secondary data was processed by GIS analysis. / text

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