Viabilidade econômica da implantação de compensadores série dinâmicos em redes de distribuição de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Análise numérica de uma geometria de coletor solar para sistemas de aquecimento de água

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dinâmica não linear e controle de um sistema vibratório modelado com memória de forma e, excitado por fontes de energia do tipo ideal e não ideal

Pós-graduação em Engenharia Mecânica - FEB

Análise matemática da potência gerada por sistemas fotovoltáicos e suas aplicações

A radiação solar constitui-se numa inesgotável fonte energética, havendo um enorme potencial de utilização por meio de sistemas de captação e conversão em outra forma de energia. Para a conversão direta da energia solar em elétrica, são utilizadas células fotovoltaicas constituídas, que associadas constituem um módulo fotovoltaico, sendo que também quando agrupados, formam painéis fotovoltaicos. Estes painéis associados a outros equipamentos que transformam ou armazenam energia elétrica para que ela possa ser utilizada é chamado de sistema fotovoltaico. Neste trabalho, foram determinadas analiticamente formas de obtenção de curvas de corrente e potência fotovoltaicas, e também o ponto de potência máxima. Tais métodos foram aplicados no sistema fotovoltaico localizado na FCA/UNESP, sendo utilizado um sistema constituído por três módulos fotovoltaicos. Para o desenvolvimento das equações que regem a potência dos sistemas fotovoltaicos, procurou-se estudar o circuito elétrico de células fotovoltaicas, sendo necessária também a aplicação de métodos numéricos iterativos para a determinação de alguns parâmetros elétricos. De acordo com os teoremas apresentados, foi possível determinar as expressões analíticas da resistência série e do ponto de potência máxima de uma célula fotovoltaica, possibilitando a geração dos gráficos de tais funções com os dados obtidos experimentalmente. Comparando-se os valores obtidos pelas funções com os valores padrões do sistema fotovoltaico instalado, o valor calculado apresentou um erro de 1,03% em relação ao dado pelo fabricante, representando uma excelente aproximação. Desta forma, pode-se concluir que os métodos e teoremas dos sistemas fotovoltaicos apresentados podem servir de auxílio a futuros dimensionamentos para aplicações destes sistemas.

Eficiência energética de sistemas de produção de mamona no Estado de Minas Gerais

The objective of this study is to determine the economical and energetic efficiency of the castor bean culture in "Zona da Mata" and South of Minas Gerais. Through the method of simulation "Monte Carlo", we verified the probabilities of occurrence of the economical, cultural and energetic efficiency indexes. In relation to the production systems of castor bean in Minas Gerais in the season 2005/2006, we established that the variables price and productivity were the most noticeable for the producers from "Zona da Mata", while in the South of Minas it was productivity. We verified that the probability of the economical efficiency index to be lower than one was 43,26% for the producers from "Zona da Mata" and 39,57% for the ones from the South of Minas. The medium price received covered the medium costs of production. However, we observed that the medium costs in these regions of Minas Gerais, were over the minimum price. Regarding the energetic analysis, the results showed that the systems in the regions studied in Minas Gerasi, presented average of cultural efficiency indexes of 8,26 and 18,89. We concluded that despite the result being favorable from the energetic point of view, from the economical sustainability point of view there is the need of a more effective support policy for the castor bean, taking into consideration that the expectations of the producers with PNPB were not confirmed.

Avaliação energética econômica do agroecossistema algodão: uma abordagem entre sistemas familiares de produção do Paraguai e do Brasil

The objective of this work was to evaluate the energy and economic efficiency indexes per unit of cotton agro-ecosystem area in family production systems of Paraguay and Brazil; and, to establish a relationship between the energy and economic. Typologies presented by the Program to Support Small Cotton Holdings (Paraguay), and by the National Program for Strengthening Family Agriculture (Brazil). Family systems of the two countries were identified; these are located from Paraguay (San Juan–CA) and from Brazil (Leme–SP). To construct the energy expenditure structure of the cotton agro-ecosystem, as well as to assess the economic efficiency, the mean values obtained were considered, when they presented similarities in production systems and they were within the typology proposed in this study. From the technical itinerary observed the Paraguayan agro-ecosystem depended (fossil fuel 56.76%) and industrial source (35.99%). Thus, the energy balance of the agricultural stage was established, which attained a value of 17,740.69 MJ ha-1; an energy efficiency of 5.28, and a cultural efficiency of 3.04. The Brazilian agro-ecosystem depended on energy from industrial source (insecticides 39.82%) and from fossil fuel (33.59%); it reached an energy balance of 19,547.88 MJ ha-1; an energy efficiency of 2.12, and a cultural efficiency index of 0.71. In the economic and energy indicator ratio, with regard to the months referring to the harvest time, that is to say, March, April, and May, the maximum economic efficiency indicator of paraguay was attained in the month of May (1,00), and from Brazil in the month of May (1,71). Both production systems analyzed were presented efficient, however, dependent of external circumstances and non-renewable energy sources.

Valiação energética e econômica do agroecossistema algodão: uma abordagem entre sistemas familiares de produção do Paraguai e Brasil

The objective of this work was to evaluate the energy and economic efficiency indexes per unit of cotton agro-ecosystem area in family production systems of Paraguay and Brazil; and, to establish a relationship between the energy and economic. Typologies presented by the Program to Support Small Cotton Holdings (Paraguay), and by the National Program for Strengthening Family Agriculture (Brazil). Family systems of the two countries were identified; these are located from Paraguay (San Juan–CA) and from Brazil (Leme–SP). To construct the energy expenditure structure of the cotton agro-ecosystem, as well as to assess the economic efficiency, the mean values obtained were considered, when they presented similarities in production systems and they were within the typology proposed in this study. From the technical itinerary observed the Paraguayan agro-ecosystem depended (fossil fuel 56.76%) and industrial source (35.99%). Thus, the energy balance of the agricultural stage was established, which attained a value of 17,740.69 MJ ha-1; an energy efficiency of 5.28, and a cultural efficiency of 3.04. The Brazilian agro-ecosystem depended on energy from industrial source (insecticides 39.82%) and from fossil fuel (33.59%); it reached an energy balance of 19,547.88 MJ ha-1; an energy efficiency of 2.12, and a cultural efficiency index of 0.71. In the economic and energy indicator ratio, with regard to the months referring to the harvest time, that is to say, March, April, and May, the maximum economic efficiency indicator of paraguay was attained in the month of May (1,00), and from Brazil in the month of May (1,71). Both production systems analyzed were presented efficient, however, dependent of external circumstances and non-renewable energy sources.

Perda de matéria seca em grãos de milho submetidos a sistemas de secagem natural e artificial.

The permanence of the corn grain in the field, after physiological maturity, is an important cause of crop losses, both in quantitative and qualitative aspect. By ceasing the supply of assimilated substances to grains, due to physiological maturity, the synthesis reactions are overcome by breathing, responsible for the maintenance of the living tissues of the grains, which occur at the expense of reserves accumulated during grain formation. In addition, there are losses from fungus and insects attack due to adverse weather conditions. Technological advances in recent decades, the develop of grain dryers with different capacities and efficiencies, has led to the early withdrawal of the product from the field, still damp, reducing spoilage. Moreover, the use of artificial drying systems can represent a significant cost to the producer. Thus, the present work aimed to study the effect of natural and artificial methods of drying on maize dry matter losses, for Botucatu, city of Sao Paulo state, Brazil. The cornfield production was conducted at the Experimental Farm “Lageado” and the experimental treatments were conducted in the Laboratory of Agricultural Products Processing, in the Department of Rural Engineering, where the drying systems were tested. The treatments were: shade (control), artificial with heated air, artificial unheated air and, drying attached to the plant. The following analyzes for quality monitoring were performed: weight test, thousand-grain weight test and, grain dry weight. The results showed significant loss in quality of drying beans attached to the plant, by assessing the dry matter loss and by the variation of the grain weight. The weight test showed that the worst performance was the artificial with heated air treatment. We used mathematical modeling techniques to describe the dry matter loss and adjusted the mathematical model to the experimental data analyzed. From the experimental data obtained during drying the grain attached to the plant, it was still possible to fit a regression model that estimates the loss of grain dry matter under the climate from Botucatu during the 2011/2012 harvest period.

Caracterização do uso da terra em diferentes épocas na bacia hidrográfica do ribeirão paraíso- são manuel sp, por meio de sistemas de informações geográficas

This study aimed to evaluate a period of 38 years, the use and soil occupation of the Paradise River watershed, inserted in the citys of São Manuel and Areiópolis-SP using aerial photographs for the year 1972 and TM image (Thematic Mapper) obtained by the Landsat-5 satellite, in 2010, using geoprocessing techniques. The watershed in question is very important for the city of São Manuel-SP, because its urban area is inserted in its divisors which part of it belongs to the Environmental Protection Area (APA) Perimeter Botucatu-SP, considered a recharge area of the aquifer Guarani. Today, the development of agriculture faces challenges, which is to produce more food without impacting the environment. Allied to this concern, research institutions have sought new technologies that allow the detection and quantification of human actions, enabling interventions in order to minimize possible damage to the environment. Among these technologies can be cited Geographic Information Systems (GIS), which a large volume of data and information stored in a region at different times can be evaluated in the same time, suggesting different approaches to the planning of land use. The results of the mapping of areas of use and soil occupation result nine classes in 1972, and the coffee culture showed the biggest occupation (37.94%) of the total area. The 2010 mapping formulated twelve classes of use, which demonstrated the predominance of sugar cane (37.94%), on the areas occupied by coffee and pasture before. The land use maps of 1972 and 2010 showed results that show intense human activity in the modification of natural landscape.

Avaliação de sistemas de manejo de palhiço de cana-de-açúcar no campo e na indústria

This work presents and it evaluates the systems of crop of sugar-cane trash for energy ends, through studies accomplished in three industries of sugar and alcohol, of the State of São Paulo, as withdrawal in the field and crop partially integral with separation of the trash in the industry (cleaning the dry). it is Treated of a development of opportunities, because only when there is pulp shortage it is that remembers the energy use of the trash, which presents a larger cost for equivalent ton in energy again that the pulp of the sugar-cane, that already has a very spread trade in the section the sugar and alcohol. Another factor that should be outstanding is the environmental, because the Environmental Protocol exists, sanctioned by most of the producing of sugar-cane, that reduces the period for elimination burned of the sugar-cane before the crop implanted by the Law 11.241 of 2002. However it is important to highlight that the crop of the sugar-cane without it burns her previous, it increases the difficulty in the combat the pest denominated “cigarrinha-da-raiz”, turning necessary the retreat of part of the trash non beneficial for the soil, contributing like this, with the practice of removal of the trash for energy use. Of the obtained results it is ended that the most interesting modality economically, was the separation of the trash in the industry and that for better efficiency, the sugar-cane should go by a double process of blowing for cleaning, pointing out, however, that there was reduction of the capacity of transport of the sugar-cane as adult was the amount of trash partially in the crop integral.

Aplicação da teoria fuzzy no controle de sistemas de geração de energias alternativas

This paper presents the application and use of a methodology based on fuzzy theory and simulates its use in intelligent control of a hybrid system for generating electricity, using solar energy, photovoltaic and wind. When using a fuzzy control system, it reached the point of maximum generation of energy, thus shifting all energy generated from the alternative sources-solar photovoltaic and wind, cargo and / or batteries when its use not immediately. The model uses three variables used for entry, which are: wind speed, solar radiation and loading the bank of batteries. For output variable has to choose which of the batteries of the battery bank is charged. For the simulations of this work is used MATLAB software. In this environment mathematical computational are analyzed and simulated all mathematical modeling, rules and other variables in the system described fuzzy. This model can be used in a system of control of hybrid systems for generating energy, providing the best use of energy sources, sun and wind, so we can extract the maximum energy possible these alternative sources without any prejudice to the environment.

Métodos de determinação da densidade do solo em diferentes sistemas de manejo

Soil bulk density is an attribute often used to characterize soil physical structure, being an indicator of soil compaction. The objective of this study was to compare the values ​​of bulk density measured by the paraffin sealed clod and volumetric ring methods in conventional, no-tillage and minimum tillage systems on a Dystroferric Red Nitosol, clayey, in Botucatu, SP. The experiment design was a 3x2 factorial arrangement in randomized block with four replications. The density values ​​obtained by the paraffin sealed clod method were statistically higher than those obtained by the volumetric ring method. There was no difference between the managements when comparing the values ​​of soil density obtained by the paraffin sealed clod method. The soil under conventional management showed lower density when comparing the values ​​of soil density obtained by the volumetric ring. The volumetric ring method was more sensitive to show differences between the management systems than the paraffin sealed clod method.

Características agronômicas e demanda energética de cultivares de soja sob efeito dos sistemas de preparo do solo

The aim of this study was to evaluate the influence of preparation: intermediate grade, minimum tillage and no-till on the agronomic characteristics and energy demand of transgenic soybean cultivars and non-GMO soybeans. Soil preparation aims at improving physical, chemical and biological conditions, aiming at good emergence and plant development. The different types of tillage may interfere with the agronomic characteristics and productivity of plants, and in energy use which can cause variation in production costs. Genetically modified plants can be one of the alternatives for reduction of production costs in crops by reducing pesticide applications, enabling higher productivity with less environmental impact. The test was conducted in 2010/2011 at the agricultural Experimental Farm Lageado, belonging to the Faculty of Agronomic Sciences – UNESP, located in the city of Botucatu, SP in an area using no-till systems for the past 12 years. The experiment was carried out in a 3 x 2 factorial, randomized treatments were comprised of three soil preparation systems, minimum cultivation, intermediate grade preparation and no-till, with two cultivars of soybeans: MGBR-46 Conquest (conventional), Valuable RR (Transgenic). The data obtained was submitted to variance analysis using Tukey test at a 5% probability. With the results analyzed it might be observed that there was no significant difference between treatments, in the variables, the percentage of soil cover, final soybean plant population, grain yield and plant height. The results obtained show that the no-till system resulted in higher productivity than conventional tillage and minimum cultivation. The higher specific energy use per area was observed in minimum cultivation with a chisel plough, when compared to the preparation across the grid. The greatest fuel consumption was to treat minimum cultivation with chisel plough. The highest values were found in the skating system of minimum cultivation, being greater in conventional tillage system. It is more satisfactory for the producer to sow transgenic soy using a no-till system, because productivity retrieved from that system compensates for fuel expenditure.

Desenvolvimento de um sistema de proteção e metodologia para localização de faltas em sistemas de distribuição

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese e caracterização de hidrogéis nanoestruturados contendo nanoargila e zeólita com potencialidade de aplicação em sistemas de liberação controlada de fármacos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)