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Over the past decade, underground power distribution has become increasingly popular due to its reliability, safety, aesthetic characteristics, as well as the ever increasing focus on the environmental impacts of the various stages of power generation and distribution. With the technological advances in this area, the process of running these cables have become more economical and efficient. This thesis explores the practice of grouping multiple three phase cables in a common conduit, using the duct bank process, and analyzes the thermal and ampacity consequences on the individual lines. This analysis is done in an effort to better define and understand the various limitations of the practice and explore future possibilities in its expansion.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

The aim of this thesis is the stiffness analysis of cable-driven parallel robots. Cable-driven parallel robots have drawn considerable attention because of their unique abilities and advantages such as the large workspace, light weight of cable actuators, easy disassembly and transportation of the robot. The mobile platform of a cable-driven parallel robot is attached to the base with multiple cables. One of the parameters that should be studied to make sure a robot is able to execute a task accurately is stiffness of the robot. In order to investigate the stiffness behaviour of a robot, the stiffness matrix can be calculated as the first step. Because cables act in tension, keeping the positive tension in cables becomes a challenge. In order to have a fully controllable robot, an actuation redundancy is needed. These complexities are addressed in the thesis and simulations. In this thesis, the complete form of the stiffness matrix is considered without neglecting any terms in calculation of the stiffness. Some stiffness indices such as single-dimensional stiffness based on stiffness ellipse, directional stiffness and condition number of the stiffness matrix are introduced and calculated and stiffness maps of the robot are developed. In addition, the issue of unit inconsistency in calculating the stiffness index is addressed. One of the areas which is also addressed in this thesis is failure analysis based on the stiffness of robot. The effect of the failure in one or more cables or motors is modelled and stiffness maps are developed for the failure situation. It is shown that by changing the anchor position and mobile platform orientation, the lost stiffness after failure of a cable or motor can be retrieved partially. Optimum anchor position and mobile platform orientation are identified to maximize the area of the stiffness map. Condition number of the stiffness matrix while robot is following a trajectory is optimized. In addition, when one cable fails during the path planning, the recovery of the robot is studied. Finally, these analyses on stiffness and failure provide the designer with the necessary and valuable information about the anchor positions and actuator toques. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2013-04-27 08:47:26.297

Electrical power transmission companies have been inspecting underground power cables in a time consuming and destructive way. The current methodology used by Manitoba Hydro, is to remove the conductive material in the center of the cable, cutting the cable into wafers leaving behind the insulating polymer material known as XLPE, the area where many faults occur, and inspect the wafers manually with a microscope. The main goal of this work was to find a methodology to detect these cable faults in a non-destructive way so that the quality of the cable may be assessed, and its remaining lifetime be estimated and return it to use if possible. Two XLPE power cable samples were tested. Three small holes were drilled in one XLPE cable. A capacitive transducer with center frequency of 802.8 kHz was applied for transmitting receiving signal. For each sample, 48 scans were collected. Based on ultrasound images, we were able to detect these faults in this XLPE material from the peaks of the samples corresponding to the XLPE area by setting a threshold to 0.08 volts. Also, this detection technique was improved by using fourth-order cumulants. / May 2016

Tesis para optar al grado de Magíster en Marketing / En la actualidad las empresas tienen múltiples alternativas de medios de comunicación en los cuales realizar sus actividades de marketing las que van desde medios tradicionales como la TV Abierta, Radio, Prensa Escrita y Vía Pública, hasta medios emergentes como la TV de Pago, los Medios Online y Cine. En este mercado, en el que la TV es el líder, ha visto la ocurrencia de varios fenómenos nuevos. Hace un par de años la Televisión Abierta, el principal medio de comunicación en términos de resultados publicitarios y de volumen de inversión, ha visto disminuir su participación en el mercado publicitario y actualmente se encuentra sumida en una crisis que ha llevado a reestructuraciones y despidos. En este contexto, las señales de TV de Pago en el país asoman como un medio alternativo interesante al poseer características comunicacionales similares a la TV Abierta (desde ser consumido en el mismo aparato, el Televisor; hasta que los mensajes publicitarios pueden ser en los mismos formatos de audio y video, integraciones en programas, entre otros), pero con características particulares al tener menores tarifas promedio, mayor fragmentación de las audiencias al tratarse de una gran cantidad de señales que se traduce en una alta capacidad de segmentación del público objetivo para la comunicación de las diferentes empresas y sus marcas. Por su volumen y hegemonía, la TV abierta ha sido frecuente objeto de estudio, respecto de las determinantes de la inversión en ese medio. Sin embargo, no ha ocurrido lo mismo con la TV de pago. Hasta ahora no existen estudios en el país que permitan identificar qué variables determinan la inversión publicitaria en las señales de esta plataforma, por lo que en la presente investigación se examinará qué variables asociadas a la inversión publicitaria son determinantes de este medio de forma de poder predecir sus resultados y determinar sus atributos versus la TV Abierta. Para ello se realizaron dos estudios mediante regresión lineal múltiple considerando datos mensuales desde Enero 2005 hasta Diciembre 2014 para ver el efecto de las variables en la inversión total del medio y respecto del total de inversión en TV. En primer lugar, se identificó que la Audiencia de la Televisión de Pago es significativa y positiva tanto para el monto total de inversión en señales de este tipo como en el share respecto a TV Abierta, lo que reafirma el hecho de que un medio de comunicación es válido como plataforma publicitaria a medida que éste tiene una audiencia relevante. En segundo lugar, se encontró que la Televisión de Pago, contrario a lo que indica la literatura sobre la publicidad, se comporta de forma anticíclica respecto de la situación económica (medida en base a la variación del IMACEC promedio de los últimos 12 meses) al dar una relación significativa pero negativa en ambos estudios (Estudio 1: β = -0,368, p0,001; Estudio 2: β = -0,039, p0,05). En tercer lugar, se determinó que las empresas toman sus decisiones de inversión publicitaria en base a la situación económica de mediano plazo y no en relación a la situación económica inmediata. En base a lo anterior se puede afirmar que las señales de Televisión de Pago funcionan como un medio de comunicación distinto a la TV Abierta, al ser más atractivas en periodos donde la TV Abierta languidece. Probablemente esto está asociado al nivel de tarifas más bajo y alta segmentación del medio, lo que permite emitir un mayor número de spots a lo largo de un mayor número de señales, logrando un mayor alcance y frecuencia de la comunicación pero sin lograr necesariamente un Rating Total (GRP) similar a la Televisión Abierta. Lo que hace destacar a la TV de Pago para determinados objetivos de marketing asociados a branding y alcance de la comunicación, especialmente en periodos donde las marcas necesitan más de este tipo de actividades.

Este trabalho apresenta a implementação computacional do elemento finito de cabo deslizando sem atrito, em ambiente MATLAB®, com a finalidade de modelar os cabos de borda não-aderentes das estruturas de membrana. Este novo elemento foi incluído no programa de análise de estruturas retesadas SATS, já previamente desenvolvido. Esta ferramenta é capaz de gerar resultados em deslocamentos, tensões e deformações em estruturas retesadas. São apresentadas as formulações utilizadas para a análise de estruturas de membrana, como a formulação do Método de Newton-Raphson para a resolução de equações não-lineares, as formulações do Elemento Finito de Treliça e do Elemento Finito de Cabo Ideal. É proposta, neste trabalho, a generalização da formulação do elemento de cabo de três nós para o super-elemento de cabo ideal de n nós. São desenvolvidas verificações da eficiência dos elementos finitos de cabo, por meio de exemplos simples de aplicação, nos quais são comparados os resultados obtidos com soluções analíticas. Por fim, é estudado o desempenho dos elementos de cabo, associados a elementos de membrana, por meio da análise da estrutura de cobertura do Memorial dos Povos de Belém do Pará. São comparados os resultados obtidos a partir da implementação das duas formulações apresentadas para os cabos, avaliando a influência da discretização e as diferenças em relação aos resultados obtidos em análises tradicionais usando elementos de treliça. Demonstra-se que a consideração do escorregamento nos cabos de borda é importante para a correta representação das tensões e deslocamentos em estruturas retesadas. / This work presents the implementation of a cable finite element, developed in MATLAB® environment, with the aim of modeling the cables at the boundary of membrane structures. It was added to a software named SATS (System for the Analysis of Taut Structures), which is able to give accurate results on displacements, stress and strains. This work also presents formulations used for the analysis of membrane structures, such as, the Newton-Raphson Method for solving non-linear equations, the Truss Finite Element and the Cable Finite Element. A generalization of the formulation from the three node cable element to an n-node cable super-element is proposed. The efficiency of the cable finite element has been verified by applying simple examples, comparing numerical results to analytical solutions. Finally, it has been studied the performance of these cable elements, along with the membrane finite elements, through the analysis of the membrane roof of the amphitheater of the Memorial dos Povos de Belém do Pará. The results from the implementation of both cable formulations and the traditional analysis using truss elements were compared. It has been shown that the consideration of the cable sliding is important for the accurate stress and displacements analysis.

Uma das marcas da passagem de uma sociedade tradicional, pessoalista, para uma sociedade moderna é o desenvolvimento da impessoalidade nas relações de sociabilidade. A cidade moderna se caracterizou por ampliar essas relações, que deixam de ser restritas aos espaços privados e passam a ocorrer também nos espaços públicos. Um dos lugares nos quais se desenvolvia a sociabilidade era nos bondes. Por terem existido no Brasil desde final do século XIX até a década de 1970, os bondes marcaram, do ponto de vista do transporte coletivo, um momento significativo do desenvolvimento do país, uma vez que estiveram presentes durante o processo de crescimento de muitas cidades, constituindo-se como um dos principais elementos indutores do crescimento urbano e de integração de diferentes espaços, como, por exemplo, entre os arrabaldes, mais adiante bairros, e o centro das cidades. A tese desenvolvida neste estudo é a de que os bondes, além de terem contribuído para o desenvolvimento urbano, integrando espaços físicos e expandindo a cidade, contribuíram também para a inserção do indivíduo na cidade moderna pelo exercício cotidiano de sociabilidade que as viagens propiciavam. Essa sociabilidade não acontecia apenas no interior dos bondes, na relação indivíduo e espaço, as aberturas laterais, que permitiam subir e descer praticamente em qualquer lugar, depois as janelas grandes e abertas, também possibilitavam que o indivíduo estivesse mais próximo do espaço físico da cidade e das pessoas que caminhavam ou se assomavam nas janelas para ver o bonde passar rente às suas calçadas. A pesquisa teve como objetivo geral investigar as representações sociais e o imaginário coletivo construído sobre as viagens de bonde e sobre a cidade durante as viagens. A partir dessas representações, buscou-se, primeiro, compreender qual o papel dos bondes como elementos estruturadores da cidade para depois analisar as interações sociais que ocorriam em seu interior e discutir a relação indivíduo-espaço. O recorte urbano temporal foi a cidade de Porto Alegre, capital do Rio Grande do Sul, entre 1890 e 1945, no alcance físico das suas linhas de bonde. A escolha por este recorte temporal deu-se pela importância que teve este período para o desenvolvimento e modernização da cidade, especialmente na área de transporte, como a construção da Av. Borges de Medeiros, Av. Farrapos e a canalização do Arroio Ipiranga, entre outras obras relevantes para a cidade. / One of the marks of the passage from a traditional society, personalistic, to a modern society is the development of impersonality in sociability relationships. The modern city is characterized by expanding these relations, which are no longer restricted to private spaces but also begin to occur in public ones. One of the places in which sociability where developed was the cable cars. According to the commom point of view, the cable cars marked a significant moment in the development of the country for having existed in Brazil since the late 19th century until the 1970s, once they were present in the growth process of many cities, establishing itself as one of the driving elements of urban growth and integration of different areas, such as, between the suburbs, further neighborhoods, and the city centers. The thesis developed in this study is that the cable cars, not only having contributed to the urban development, by integrating physical spaces and expanding the city, but also contributed to the insertion of the individual in the modern city by the daily sociability exercise which the trips provided. This sociability did not just happened inside the cable cars, the individual and space relationship, the side openings, which allowed passengers to get on and off almost anywhere, and the big and open windows also made it possible for the individual to be close to the physical space of the city and the people who walked or loomed by the window to see the cable car pass close to its sidewalks. The research aimed to investigate the social representations and the collective imaginary built on the cable car rides and the city during these trips. From these representations, it was sought to first understand which role the cable cars had, as structural elements of the city, and then analyse the social interactions that took place inside it and the relationship between individual and space. The temporal urban range was Porto Alegre, the capital of Rio Grande do Sul, between 1890 e 1945, in its cable car extension lines. The choice for this time range was given by the importance this period had for the city development and modernization, especially in the transport area, such as the construction of Borges de Medeiros Ave., Farrapos Ave. and the canalization of Arroio Ipiranga, among other relevant works for the city.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH / Bibliography: leaves 80-81. / by Marsha Regenstein. / M.C.P.

This dissertation poses that the digital transition is best understood as simultaneously a technological and cultural phenomena. As a physical change in the means of distribution, transmission, and reception of media content, the digital transition is an important factor in changing technological, aesthetic, and legal norms. As a cultural form, the digital is positioned as a moderator between continuity and discontinuity. Through a reading strategy inspired by Walter Benjamin this dissertation reads the physical and cultural implications of the digital transition in television in the United States through political categories. The chapters are case studies in the adoption of digital televisions for home use, digital television production technologies, digital transmission technologies, and digital distribution systems. Each case study examines the tenuous production of publics in the context of the dialectical pressures of the digital. By taking this approach I intend to contribute to the rhetorical dimension of television studies, the digital turn in rhetorical and public sphere studies, and the legal and aesthetic dimensions of production studies. The dialectical approach to the digital allows the study of television to theorize the trajectory of emerging media and the political implications of that movement.