Sensoriamento óptico quase-distribuído aplicado ao monitoramento de trocadores de calor de usinas hidrelétricas

This work aims to develop optical sensors for temperature monitoring in hydroelectric power plant heat exchangers. The proposed sensors are based on the Fiber Bragg Gratings technology. First of all, a prototype with three sensors inscribed in a same fiber was developed. This fiber was then fixed to a conventional Pt100 sensor rod and inserted in a thermowell. The ensemble was then calibrated in a workbench, presenting a maximum combined uncertainty of 2,06 °C. The sensor was installed in one of the heat exchangers of the Salto Osório’s hydroelectric power plant. This power plant is situated in the Iguaçu river, at the Paraná state. Despite the satisfactory results, the sensor was improved to a second version. In this, fifteen optical Bragg sensors were inscribed in a same fiber. The fixation with a conventional sensor was no longer necessary, because the first version results comproved the efficiency and response time in comparison to a conventional sensor. For this reason, it was decided to position the fiber inside a stainless steel rod, due to his low thermal expansion coefficient and high corrosion immunity. The utilization of fifteen fiber Bragg gratings aims to improve the sensor spatial resolution. Therefore, measurements every ten centimeters with respect to the heat exchanger’s height are possible. This provides the generation of a thermal map of the heat exchanger’s surface, which can be used for determination of possible points of obstruction in the hydraulic circuit of the heat exchanger. The heat exchanger’s obstruction in hydroelectric power plants usually occur by bio-fouling, and has direct influence in the generator’s cooling system efficiency. The obtained results have demonstrated the feasibility in application of the optical sensors technology in hydroelectric power plants.

Sistema de emulação de aerogeradores para aplicação em geração distribuída de energia elétrica

Power generation from alternative sources is at present the subject of numerous research and development in science and industry. Wind energy stands out in this scenario as one of the most prominent alternative in the generation of electricity, by its numerous advantages. In research works, computer reproduction and experimental behavior of a wind turbine are very suitable tools for the development and study of new technologies and the use of wind potential of a given region. These tools generally are desired to include simulation of mechanical and electrical parameters that directly affect the energy conversion. This work presents the energy conversion process in wind systems for power generation, in order to develop a tool for wind turbine emulation testing experimental, using LabVIEW® software. The purpose of this tool is to emulate the torque developed in an axis wind turbine. The physical setup consists of a three phase induction motor and a permanent magnet synchronous generator, which are evaluated under different wind speed conditions. This tool has the objective to be flexible to other laboratory arrangements, and can be used in other wind power generation structures in real time. A modeling of the wind power system is presented, from the turbine to the electrical generator. A simulation tool is developed using Matlab/Simulink® with the purpose to pre-validate the experiment setup. Finally, the design is implemented in a laboratory setup.

Controle de uma microrrede ilhada baseada em geração eólica-diesel com alto nível de inserção de geração eólica

The insertion of distributed generation units in the electric power systems have contributed to the popularization of microgrid concepts. With the microgrids, several potential benefits can be achieved in regard to power quality and supply reliability. However, several technical challenges related to the control and operation of microgrids, which are associated with high insertion of generation systems based on static converters, must be overcame. Among the opportunities in the context of microgrids, there is the islanded operation of microgrids temporarily disconnected from the electric power systems and also the autonomous operation of geographically isolated microgrids. The frequency in large power systems is traditionally controlled by the generation units based on traditional synchronous generator. The insertion of distributed generation units based on static power converters may bring difficulties to the frequency control in microgrids, due to the reduction of the equivalent inertia of conventional synchronous generators present in islanded and isolated microgrids. In this context, it becomes necessary the proposition of new operational and control strategies for microgrids control, taking into account the presence of distributed generation units based on full-rated converter. This paper proposes an operational and control strategy for the islanded operation of a winddiesel microgrid with high insertion level of wind generation. The microgrid adopted in this study comprises of a wind energy conversion system with synchronous generator based on full rated converter, a diesel generator (DIG) and a dump load. Due to the high insertion level of wind generation, the wind unit operates in Vf mode and the diesel generator operates in PQ mode. The diesel generator and the dump load are used to regulate the DC-link voltage of the wind generation unit. The proposed control allows the islanded operation of the microgrid only with wind generation, wind-only mode (WO), and with wind-diesel generation, wind-diesel mode (WD). For the wind-only mode, with 100% of penetration level of wind generation, it is proposed a DC-link voltage control loop based on the use of a DC dump load. For the winddiesel mode, it is proposed a DC-link voltage control loop added to the diesel generator, which is connected to the AC side of the microgrid, in coordinated action with the dump load. The proposed operational and control strategy does not require the use of batteries and aims to maximize the energy production from wind generation, ensuring the uninterrupted operation of the microgrid. The results have showed that the operational and control strategy allowed the stable operation of the islanded microgrid and that the DC-link voltage control loop added to the diesel generator and the dump load proved to be effective during the typical variations of wind speed and load.

Uma contribuição para a medição de distorções harmônicas e inter-harmônicas em instalações de geração fotovoltaica

Dissertação (mestrado)— Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2015.

Uma abordagem dirigida a modelo para a geração de casos de teste baseada na detecção de cenários implícitos

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2015.

A Geração de inovação na carcinicultura do RN: Uma análise a partir da imersão social

This dissertation examines the organizational innovation as a nonlinear process, which occurs in a social and political context and, therefore, socially immersed. Examines the case of shrimp in the state of RN, starting from the following problem: although the norteriograndense shrimp occupies the largest producer of farmed shrimp from Brazil, has a series of bottlenecks concerning the generation of industry innovation, concerning the social relationships and policies between the various actors in the network, whether private or public, and its consequences in terms of opportunity and limits generated for the innovative dynamics. The objective of the research is to understand how the social embeddedness of political actors affects norteriograndense shrimp within the context of structural relations, the industry generation of innovation, throughout its technological trajectory . The approach of social embeddedness balances atomised perspectives, undersocialized and oversocialized, of economic action, considering both the human capacity to act as sources of constraint, whose mechanisms are analyzed the structural and political. In methodological terms this is a case study, analyzed from the research literature, documentary and experimental. Primary data were collected through semi-structured interviews and analyzed in depth by the technique of content analysis. Was adopted a longitudinal approach, seeking to understand the phenomenon from the perspective of the subjects, describing it in an inductive process of investigation. After characterizing the sector and defining their technological trajectory, the analysis of the results followed its four stages: (1) Introduction of Technology: 1973-1980, (2) Intensification of Research: 1981-1991, (3) Technological Adaptation, 1992 -2003, (4) Technological Crisis: 2004-2009. A cross-sectional analysis along the evolutionary trajectory revealed the character of structural changes and policies over time, and implications on the generating process of innovation. Note that, the technological limit to which the sector reached requires changes in technology standards, but is more likely that the potiguar shrimp is entering a new phase of his career in technology rather than a new technological paradigm

A influência das redes sociais na perceção e escolha de um destino turístico na Geração Y

As redes sociais têm potencial para influenciar os indivíduos nas suas escolhas. O objetivo deste estudo é perceber se as redes sociais têm influência na perceção e escolha de um destino turístico por parte dos utilizadores. No sentido de entender todo o processo de partilha de conteúdos por parte dos utilizadores online, no que toca à divulgação de destinos turísticos, foi escolhida como referência a maior rede social a nível mundial - o facebook. Foi adotada uma metodologia quantitativa, assente na construção de um questionário colocado online a cerca de 250 pessoas, utilizadores de facebook, de ambos os sexos, e com idades compreendidas entre os 16 e os 32 anos – Geração Y ou geração Millennium. Os dados recolhidos foram tratados e analisados com o auxílio do software SPSS e do Google Forms. Foi possível, nesta investigação, identificar a sensibilidade dos indivíduos face à partilha de conteúdos turísticos realizados por amigos, familiares e ícones nas redes sociais. Este estudo é importante no sentido em que as empresas ligadas ao sector podem incentivar os utilizadores a partilhar as suas férias e conteúdos na página da empresa e tornar-se, assim, numa estratégia de marketing potenciando quer a sua visibilidade organizacional, quer a do destino em causa.

Jovens terena na cidade de Campo Grande (MS): política e geração

Research with indigenous in urban context are gaining steam in recent years, particularly with the intensification of migration resulting from problems such as lack of land for subsistence. However, in relation to Terena, subjects in this study, the contemporary anthropological research aimed at residents in cities still are not privileged, especially to youth. Thus, the dissertation has as main objective the discussion around some axes, among them indigenous youth Terena ethnicity politics, - indigenous movement - and racism. These themes appeared during fieldwork where privileged six trajectories of young Terena who migrated to Campo Grande (MS) and have different ways to mean the city and experiencing everyday life

Políticas de geração distribuída e sustentabilidade do sistema elétrico

Tese (doutorado)—Universidade de Brasília, Centro de Desenvolvimento Sustentável, 2015.

Escalonamento de tripulações : geração de cadeias de voo para uma frota de médio curso

Mestrado em Métodos Matemáticos para Gestão de Empresas

Prevalencia de anemia, asociada a coeficiente intelectual en escolares de 6 a 12 años de Cuenca, 2007

Objetivo: Determinar la prevalencia de anemia en escolares de 6 a 12 años del área urbana de la ciudad de Cuenca y su relación con el coeficiente intelectual. Diseño: Se realizó un estudio transversal durante los meses de noviembre y diciembre de 2007 en el área urbana de la ciudad de Cuenca del austro ecuatoriano. Se eligieron 4 escuelas aleatoriamente hasta completar el tamaño muestral de 261 niños. Se recogieron los datos antropométricos (peso y talla); se determinaron los valores de hemoglobina y se realizó un test psicológico. Resultados: La prevalencia general de anemia fue de 9,6, y de los escolares afectados el 77,77tenían anemia por déficit de hierro. El parámetro antropométrico que mostró la mayor asociación con la presencia de anemia fue la relación entre la estatura y la edad (OR: 1,35 IC: 1,33 - 9,21). La variable anemia se asoció significativamente al coeficiente intelectual en un 17. El porcentaje de niños con desnutrición crónica fue de 11,9y riesgo de desnutrición del 15,7El tipo de escuela se asoció levemente al coeficiente intelectual (p= 0.03) (OR: 1,87 IC: 1,05 - 3,39). No se encontró ninguna relación entre la prevalencia de anemia por un lado, y el sexo por el otro. Tampoco existió relación entre la variable sexo y el coeficiente intelectual. Conclusiones: La anemia en general y la anemia ferropénica en particular, no constituyen un problema de salud pública en la población estudiada. Los escolares con talla alta tienen menor riesgo de desarrollar anemia. La anemia se asoció significativamente al coeficiente intelectual

Avaliação econômica do sistema de produção de mudas de seringueira (Hevea brasiliensis) com copas enxertadas resistentes ao Mal-das-Folhas.

O objetivo deste trabalho foi avaliar o custo unitário da produção de mudas de seringueira tricomposta, como possibilidade de diversificação de cultura e geração de renda entre os agricultores.

Avaliação do desempenho econômico e do potencial de geração de renda da estrutura produtiva de pequena escala de dendezeiro híbrido interespecífico na mesorregião metropolitana de Belém, Pará.

2016