Esta pesquisa analisa o comportamento variável das oclusivas dentais /t/ e /d/ seguidas de [i] na fala de informantes das comunidades linguísticas de Santa Vitória do Palmar e Chuí, de acordo com os parâmetros da Teoria da Variação Linguística de Labov (1972). A amostra é proveniente do corpus pertencente ao projeto “Coleta de corpus nos municípios de Santa Vitória do Palmar e Chuí”, da Universidade Federal do Rio Grande – FURG. Os dados coletados foram submetidos a tratamento estatístico com o uso do programa de análise multivariada Goldvarb, nas versões 2001 e 2005. Este estudo tornou possível a conclusão de que a ocorrência da Africada Alveolar, variante bastante produtiva nos referidos municípios e frequente na fala das mulheres mais velhas e de baixa escolaridade, é uma regra variável, sujeita a condicionamentos linguísticos e extralinguísticos. / This research analyzes the variable behavior of dental stops /t/ e /d/ followed by [i] in the speech of informants of the language communities of Santa Vitória do Palmar and Chuí, according to the parameters of the Theory of Linguistic Variation (Labov, 1972). The sample is from the corpus belonging to the project “Coleta de corpus nos municípios de Santa Vitória do Palmar e Chuí”, from Universidade Federal do Rio Grande – FURG. The data collected were analyzed statistically with the use of the multivariate analysis program Goldvarb, versions 2001 and 2005. This study made possible the conclusion that the occurrence of alveolar affricate, very productive variant in these cities and often in the speech of older women with low education, is a variable rule, subject to linguistic and social conditioning.

There is a current requirement for technologies that store heat for both domestic and industrial applications. Phase-change materials (PCMs) represent an important class of materials that offer potential for heat storage. Heat-storage systems are required to undergo multiple melt/freeze cycles without any change in melting-crystallisation point and heat output. Salt hydrates are attractive candidates on account of their high energy densities, but there are issues associated with potential crystallisation of lower-hydrates, long-term stability, and reliable nucleation. An extensive review of the PCMs in the literature, combined with an evaluation of commercially available PCMs led to the conclusion that many of the reported PCMs, lack at least one of the key requirements required for use as a heat-storage medium. The focus of this research was therefore to identify and characterise new PCM compositions with tailored properties. New PCM compositions based of sodium acetate trihydrate were developed, which showed improved properties through the use of selective polymers that retard the nucleation of undesirable anhydrous sodium acetate. Furthermore, the mechanism of nucleation of sodium acetate trihydrate by heterogeneous additives has been investigated using variable-temperature powder X-ray diffraction. This study showed that when anhydrous Na2HPO4 was introduced to molten sodium acetate trihydrate at 58°C the hydrogenphosphate salt is present as the dihydrate. On heating to temperatures in the range 75-90°C the dihydrate was observed to dehydrate to form anhydrous Na₂HPO4. This result explains the prior observation that the nucleator is deactivated on heating. The depression of melting point of sodium acetate trihydrate caused by the addition of lithium acetate dihydrate has also been investigated using differential scanning calorimetry and powder X-ray diffraction. It has been possible to tune the melting point of sodium acetate trihydrate thereby modifying its thermal properties. Studies of the nucleation of sodium thiosulfate pentahydrate, a potential PCM, led to the structural characterisation of six new hydrates using single crystal Xray diffraction. All of these hydrates can exist in samples with the pentahydrate composition at temperatures ranging from 20°C to 45°C. These hydrates are: α-Na₂S₂O₃·2H₂O, which formed during the melting of α-Na₂S₂O₃·5H₂O; two new pentahydrates, β-Na₂S₂O₃·5H₂O and γ-Na₂S₂O₃·5H₂O; Na₂S₂O₃·1.33 H₂O, β-Na₂S₂O₃·2H₂O and Na₂S₂O₃·3.67 H₂O, which formed during the melting of β- Na₂S₂O₃·5H₂O. Furthermore, new PCMs in the 75-90°C range were identified. The commercial impact and route to market of several of the PCMs are discussed in the final chapter.

At present many remote and Island communities rely solely on diesel powered generators to provide electricity. Diesel fuel is both expensive and polluting and the constant speed operation of the diesel engine is inefficient. In this thesis the use of renewable energy sources to help offset diesel fuel usage and an alternative way of running the diesel generator with the aim of reducing electrical energy costs is investigated. Diesel generators have to be sized to meet peak demand, in one or two diesel generator island grids, these generators will be running at a fraction of maximum output for most of the time. A new variable speed diesel generator allows for a reduction in fuel consumption at part load compared to constant speed operation. Combining the variable speed diesel generator with renewable generation should maximise the diesel fuel offsetting of the renewable source due to the increased efficiency at low loads. The stability issues of maintaining transient performance in a renewable variable speed hybrid system have been modelled and simulated. A control strategy has been developed and the use of energy storage as a buffer for any remaining stability problems has been explored. The control strategy has then been experimentally tested along with one of the possible energy storage solutions. An economic feasibility study has been performed on a case study community to validate the main aim of this research of reducing the cost of electrical energy in diesel generator grids.

A manufatura de produtos customizados resulta em variedade de modelos, redução no tamanho de lotes e alternância frequente de tarefas executadas por trabalhadores. Neste contexto, tarefas manuais são especialmente afetadas por conta do processo de adaptação do trabalhador a novos modelos de produtos. Este processo de aprendizado pode ocorrer de maneira distinta dentro de um grupo de trabalhadores. Assim, busca-se o agrupamento dos trabalhadores com perfis similares de aprendizado, monitorando a formação de gargalos em linhas de produção constituídas por dissimilaridades de aprendizado em processos manuais. A presente dissertação apresenta abordagens para clusterização de trabalhadores baseadas nos parâmetros oriundos da modelagem de Curvas de Aprendizado. Tais parâmetros, os quais caracterizam o processo de adaptação de trabalhadores a tarefas, são transformados através da Análise de Componentes Principais e então utilizados como variáveis de clusterização. Na sequência, testam-se outras transformações nos parâmetros utilizando funções Kernel. Os trabalhadores são clusterizados através do método K-Means e Fuzzy C-Means e a qualidade dos agrupamentos formados é medida através do Silhouette Index. Por fim, sugere-se um índice de importância de variável baseado em parâmetros obtidos na Análise Componentes Principais com o objetivo de selecionar as variáveis mais relevantes para clusterização. As abordagens propostas são aplicadas em um processo da indústria calçadista, gerando resultados satisfatórios quando comparados a clusterizações realizadas sem a transformação prévia dos dados ou sem seleção das variáveis. / Manufacturing of customized products relies on a large menu choice, reduced batch sizes and frequent alternation of tasks performed by workers. In this context, manual tasks are especially affected by workers’ adaptation to new product models. This learning process takes place in different paces within a group of workers. This thesis aims at grouping workers with similar learning process tailored to avoid bottlenecks in production lines due to learning dissimilarities among workers. For that matter, we present a method for clustering workers based on parameters derived from Learning Curve (LC) modeling. Such parameters are processed through Principal Component Analysis (PCA), and the PCA scores are used as clustering variables. Next, Kernel transformations are also used to improve clustering quality. The data is clustered using K-Means and Fuzzy C-Means techniques, and the quality of resulting clusters is measured by the Silhouette Index. Finally, we suggest a variable importance index based on parameters derived from PCA to select the most relevant variables for clustering. The proposed approaches are applied in a footwear process, yielding satisfactory results when compared to clustering on original data or without variable selection.

Técnicas como a harmonização da velocidade procuram gerir e controlar o tráfego com base nas condições de tráfego das rodovias em tempo real. A harmonização da velocidade utiliza limites de velocidade variáveis (L.V.V.) para fornecer aos condutores uma velocidade de operação mais apropriada, normalmente inferior ao limite de velocidade estático indicado, em resposta as condições dinâmicas das vias. O L.V.V. tem demonstrado capacidade de melhorar a mobilidade e a segurança nas rodovias. Com isso, modelos de avaliação de risco de colisão em tempo real são frequentemente adotados para quantificar os riscos de ocorrência de colisões em estudos de implantação do L.V.V. Na maioria dos estudos sobre L.V.V., modelos de probabilidade de colisão são adotados apenas para mensurar o desempenho do sistema. Estes algoritmos de controle de L.V.V. não levam em conta o risco de colisões em períodos futuros, e assim não usam impactos do L.V.V. para escolher o plano de controle com relação à segurança. No Brasil, estratégias de harmonização da velocidade não são empregadas. Como as condições de tráfego nas rodovias brasileiras não são homogêneas, e cada faixa de tráfego normalmente possui médias de velocidades, intensidades de fluxo e composições de tráfego diferentes, técnicas como o L.V.V Podem oferecer benefícios ao harmonizar as velocidades entre as faixas e assim retardar o aparecimento de congestionamentos, reduzir o número de ultrapassagens e o risco de colisões. Dessa forma, este trabalho busca avaliar a relação entre as características do tráfego e a probabilidade de ocorrer conflitos entre veículos, para assim desenvolver um modelo matemático capaz de expressar tal relação – usando como estudo de caso um trecho da rodovia BR-290/RS, situada na região metropolitana da cidade de Porto Alegre. Este modelo matemático alimenta um algoritmo L.V.V., empregado em um micro simulador de tráfego, para controlar o tráfego com o objetivo de aumentar a segurança. Resultados indicam que o modelo proposto classificou corretamente 87% dos conflitos efetivamente ocorridos em campo. Os resultados de simulação indicam que o emprego do sistema L.V.V. contribuiu significativamente para a redução da probabilidade de conflitos. Ainda, o L.V.V. aumentou as velocidades médias nos períodos de fluxo elevado, e também reduziu o desvio padrão das velocidades – oferecendo um tráfego mais homogêneo – que contribui para a redução do número de trocas de faixa e, consequentemente, para um aumento da segurança. / Techniques such as speed harmonization seek to manage and control traffic based on road traffic conditions in real time. Speed harmonization uses variable speed limits (VSL) to provide drivers with a more appropriate speed, usually below the stated static speed limit, in response to dynamic road conditions. The VSL has demonstrated its ability to improve mobility and road safety. Thus, real-time collision risk assessment models are often adopted to quantify the risk of collisions occurring in VSL implantation studies. In most VSL studies, collision probability models are utilized only to measure the system performance. These VSL control algorithms do not take into account the risk of collisions in future periods, and thus do not use the VSL impacts to choose the control plan concerning safety. In Brazil, Speed harmonization strategies are not employed yet. As the traffic conditions on Brazilian highways are not homogeneous, and each traffic range usually has different average speeds, flow intensities, and traffic compositions, VSL techniques can offer benefits by harmonizing speeds between lanes, slowing down congestion, reducing the number of overtaking and the risk of collisions.( Continue) Thus, this work seeks to evaluate the relationship between traffic characteristics and the probability of conflicts between vehicles, in order to develop a mathematical model capable of expressing such a relation - using as a case the BR-290/RS freeway, located in the Porto Alegre metropolitan area. This mathematical model will then feed a VSL algorithm, employed in a micro traffic simulator, to control traffic and increase safety. Results indicate that the proposed model correctly classified 87% of the conflicts actually occurred in the field. The simulation results indicate that the VSL contributed significantly to reducing the conflicts likelihood. Even more, the VSL increased the average speeds for high flow periods, and also reduced the standard deviation of speeds - offering a more homogeneous traffic - which contributes for reduction in the number of lane changes and, consequently, to an increase in safety.

Portfolio selection theory, developed by Markowitz (1952), is one of the best known and widely applied methods for allocating funds among possible investment choices, where investment decision making is a trade-off between the expected return and risk of the portfolio. Many portfolio selection models have been developed on the basis of Markowitz's theory. Most of them assume that complete investment information is available and that it can be accurately extracted from the historical data. However, this complete information never exists in reality. There are many kinds of ambiguity and vagueness which cannot be dealt with in the historical data but still need to be considered in portfolio selection. For example, to address the issue of uncertainty caused by estimation errors, the robust counterpart approach of Ben-Tal and Nemirovski (1998) has been employed frequently in recent years. Robustification, however, often leads to a more conservative solution. As a consequence, one of the most common critiques against the robust counterpart approach is the excessively pessimistic character of the robust asset allocation. This thesis attempts to develop new approaches to improve on the respective performances of the robust counterpart approach by incorporating additional investment information sources, so that the optimal portfolio can be more reliable and, at the same time, achieve a greater return.

A operação de adubação responde por parte significativa dos custos de produção agrícola. Melhorar a qualidade dessa operação acarreta benefícios econômicos e ambientais. O processo de adubação normalmente é realizado a uma taxa média, representativa de uma área, no entanto, propriedades químicas do solo podem variar consideravelmente dentro dessa área. Desse modo, alguns locais poderão receber fertilizantes e/ou corretivos em excesso, enquanto outros poderão receber quantidades insuficientes. A alternativa à taxa média é a realizar a aplicação à taxa variada, que se caracteriza por aplicar os insumos de acordo com as necessidades específicas dentro da área. Para que essa aplicação aconteça, mecanismos dosadores controlam a aplicação. O objetivo deste estudo é avaliar os mecanismos dosadores de uma carreta adubadora de arrasto, comportas e esteiras, atendem as prescrições de doses previstas no mapa de recomendação de adubação. Para avaliar a uniformidade da operação utilizou-se o controle estatístico do processo. De acordo com os resultados obtidos pode-se afirmar que os mecanismos dosadores não atenderam a condição de realizar a aplicação à taxa variável de maneira uniforme. / The operation fertilization accounts for a significant portion of the costs of agricultural production. Improve the quality of this operation entails economic and environmental benefits. The process of fertilization is usually performed at an average rate representative of an area, however, the chemical properties of soil can vary considerably within the area. Thus, some locations may receive fertilizer and / or lime in excess, while others may receive insufficient amounts. The alternative is to average the application to perform variable rate, characterized by applying inputs according to the specific requirements within the area. For this application happens, metering mechanisms control the application. The aim of this study is to evaluate the dosing mechanisms of a truck hauling fertilizer, locks and mats, meet the requirements of the prescribed dose map fertilizer recommendation. To evaluate the uniformity of operation used the statistical process control. According to the obtained results it can be stated that the meter mechanism did not meet the condition to perform variable rate application to uniformly.

A proposta do modelo computacional (DIMREDE) para dimensionamento de redes coletoras de esgotos sanitários de grande porte, a partir de um traçado conhecido, fundamenta-se na sua importância sanitária e ambiental, e na necessidade de minimizar os custos totais de tais sistemas. O modelo é destinado a microcomputadores, atendendo, portanto, aos requisitos de portabilidade. As redes de esgoto são projetadas para o regime de escoamento livre, embora em alguns casos, seja necessária a introdução de estações elevatórias em determinados pontos do sistema. O modelo prevê a incorporação dessas elevatórias, quando necessário, adicionando os respectivos custos no cômputo dos custos totais. As funções de custos utilizadas são baseadas em dados de redes executadas por companhias de saneamento do país. O DIMREDE permite também que, a equação governante da hidráulica de Hazen-Williams modificada, seja empregada. Trata-se de uma expressão que contempla fatores como a lâmina e velocidade de escoamento, diâmetro, declividade, material empregado no revestimento do conduto e viscosidade do fluido, na determinação do coeficiente de rugosidade, apresentando, desta forma, resultados mais condizentes com a realidade. / A computational model (DIMREDE) is proposed for design of large sewer networks whose layouts whose layouts are defined, based on their sanitary and environmental importance, as well as the costs minimization. The model is designed for microcomputers satisfying the portability criterion. In spite of the sewer networks being designed under free flow, many times the introduction of pump stations in such systems is necessary. The model evaluates costs of pump stations as part of the total cost function in terms of sewer networks already implemented by sanitation companies in Brazil. The DIMREDE program employs the modified Hazen-Williams equation for the system hydraulics, admiting that factors like depth, velocity, diameter, slope, lining material and fluid viscosity be considered in the determination of the coefficient of roughness, for obtaining more realistic results.

Student Number : 0400486V - MSc (Eng) dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / The Voltage Dip Test Facility at the University of the Witwatersrand utilises a resistive load during testing of variable speed drives. This method produces valuable results regarding the performance of drives under dip conditions. It has been shown that load type does influence the performance of drives and this variation cannot be tested under current conditions as only linear loading is attainable with resistive loads. This thesis proposes a programmable load based on the concept of field-oriented control of an induction motor. The concepts involved with field-oriented control are discussed and shown to be suitable for this application. An implementation strategy utilising custom-designed software and an off-the-shelf VSD is developed and executed. The performance of the programmable load is analysed under both steady-state and dynamic conditions.

O total de gasto social do governo somou cerca de R$800 bilhões em 2009, quase 25% do PIB brasileiro. Dado este volume crescente e expressivo, esta dissertação apresenta uma análise do efeito do gasto social sobre a pobreza no Brasil das três instâncias de governo: federal, estadual e municipal. Para tanto, foram estimados três modelos com dados em painel de 20 anos (1987 a 2009) analisando os gastos estaduais e federais. Adicionalmente, estimou-se o efeito da despesa municipal utilizando dados de 1991, 2000 e 2010 para 5.058 municípios. Procurou-se tratar o viés de simultaneidade entre o gasto do governo e a pobreza aplicando-se o modelo de mínimos quadrados em dois estágios, utilizando variáveis de ideologia política como instrumento. Os resultados mostraram que o gasto das três instâncias de governo tem efeito sobre a queda da pobreza no Brasil. Particularmente, as funções orçamentárias de gasto que apresentaram maior efetividade sobre a queda da pobreza foram: gasto federal e municipal com saúde e saneamento e gastos agregados estaduais e municipais. Analisou-se também o efeito da interação do gasto estadual com dados das condições iniciais de cada estado em 1980 - renda familiar per capita, desigualdade, proporção de pobres, grau de educação e mortalidade infantil. Concluiu-se que tanto as condições iniciais de cada estado como suas características específicas influenciam o grau em que o seu gasto afeta a pobreza. / The total public social spending in Brazil reached about R$800 billion in 2009, almost 25% of Brazilian GDP. Giving this increasing and expressive volume, this dissertation analyzes the effect of the three levels of government social spending on poverty in Brazil - federal, state and municipal. Three models were estimated with a 20 year\'s state panel data (1987 to 2009) analyzing the federal and state spending effect. We also estimated the municipal expenditure effect on poverty using data from 1991, 2000 and 2010 in 5.058 municipalities. The simultaneity bias between government spending and poverty was treated by applying the two stages least squares method, using the political ideology as instrumental variables. The results showed that the spending of the three levels of government reduce poverty in Brazil. Particularly, the spending budget functions with higher effectiveness on reduce poverty are: federal and municipal spending on health and sanitation, state and local aggregated spending. In addition, we also analyzed the effect of the state spending data interacting with its initial conditions in 1980 - per capita income, inequality, poverty, level of education and infant mortality. We concluded that the states initial conditions as well as its specific characteristics influence the extent to which their spending affects poverty.