Contribuições ao método de rastreamento de máxima potência para sistemas fotovoltaicos

The scarcity of natural resources and the search for alternative energy sources promote a rapid change in the energy world. Among the renewable energy sources, solar energy is the most promising, presenting technology of greatest growth rate nowadays. Researchers around the world are seeking ways to facilitate their progress, developing technologies with higher efficiency and lower cost. As a contribution to global progress, this master thesis proposes the development of a strategy of maximum power tracking based on perturbation and observation method for photovoltaic systems. The proposed control strategy is based on active power balance of the system, with a reduced number of sensors. It also allows the PV system to act as a regulator of the power quality at the point of commom coupling (PCC), compensating the harmonic distortion and power factor of the current netw

Implementação paralela escalável e eficiente do algoritmo simplex padrão em arquitetura multicore

This work presents a scalable and efficient parallel implementation of the Standard Simplex algorithm in the multicore architecture to solve large scale linear programming problems. We present a general scheme explaining how each step of the standard Simplex algorithm was parallelized, indicating some important points of the parallel implementation. Performance analysis were conducted by comparing the sequential time using the Simplex tableau and the Simplex of the CPLEXR IBM. The experiments were executed on a shared memory machine with 24 cores. The scalability analysis was performed with problems of different dimensions, finding evidence that our parallel standard Simplex algorithm has a better parallel efficiency for problems with more variables than constraints. In comparison with CPLEXR , the proposed parallel algorithm achieved a efficiency of up to 16 times better

Controle automático para injeção otimizada de gás em poços de petróleo equipados para funcionamento com gás lift contínuo

The continuous gas lift method is the main artificial lifting method used in the oil industry for submarine wells, due to its robustness and the large range of flow rate that the well might operate. Nowadays, there is a huge amount of wells producing under this mechanism. This method of elevation has a slow dynamics due to the transients and a correlation between the injected gas rate and the of produced oil rate. Electronics controllers have been used to adjust many parameters of the oil wells and also to improve the efficiency of the gas lift injection system. This paper presents a intelligent control system applied to continuous gas injection in wells, based in production s rules, that has the target of keeping the wells producing during the maximum period of time, in its best operational condition, and doing automatically all necessary adjustments when occurs some disturbance in the system. The author also describes the application of the intelligent control system as a tool to control the flow pressure in the botton of the well (Pwf). In this case, the control system actuates in the surface control valve

Dinâmica Estocástica e Cosmologia: alguns resultados analíticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Evolução top-hat hidrodinâmica em campos de velocidades peculiares primordiais

We investigate the cosmology of the vacuum energy decaying into cold dark matter according to thermodynamics description of Alcaniz & Lima. We apply this model to analyze the evolution of primordial density perturbations in the matter that gave rise to the first generation of structures bounded by gravity in the Universe, called Population III Objects. The analysis of the dynamics of those systems will involve the calculation of a differential equation system governing the evolution of perturbations to the case of two coupled fluids (dark matter and baryonic matter), modeled with a Top-Hat profile based in the perturbation of the hydrodynamics equations, an efficient analytical tool to study the properties of dark energy models such as the behavior of the linear growth factor and the linear growth index, physical quantities closely related to the fields of peculiar velocities at any time, for different models of dark energy. The properties and the dynamics of current Universe are analyzed through the exact analytical form of the linear growth factor of density fluctuations, taking into account the influence of several physical cooling mechanisms acting on the density fluctuations of the baryonic component of matter during the evolution of the clouds of matter, studied from the primordial hydrogen recombination. This study is naturally extended to more general models of dark energy with constant equation of state parameter in a flat Universe

Aplicações da q-Álgebra em física da matéria condensada

We address the generalization of thermodynamic quantity q-deformed by q-algebra that describes a general algebra for bosons and fermions . The motivation for our study stems from an interest to strengthen our initial ideas, and a possible experimental application. On our journey, we met a generalization of the recently proposed formalism of the q-calculus, which is the application of a generalized sequence described by two parameters deformation positive real independent and q1 and q2, known for Fibonacci oscillators . We apply the wellknown problem of Landau diamagnetism immersed in a space D-dimensional, which still generates good discussions by its nature, and dependence with the number of dimensions D, enables us future extend its application to systems extra-dimensional, such as Modern Cosmology, Particle Physics and String Theory. We compare our results with some experimentally obtained performing major equity. We also use the formalism of the oscillators to Einstein and Debye solid, strengthening the interpretation of the q-deformation acting as a factor of disturbance or impurity in a given system, modifying the properties of the same. Our results show that the insertion of two parameters of disorder, allowed a wider range of adjustment , i.e., enabling change only the desired property, e.g., the thermal conductivity of a same element without the waste essence

Propagação de danos para o modelo Ising em uma rede quadrada totalmente frustrada

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Desempenho e efeitos agudos da espirometria de incentivo volume-orientada sobre os volumes pulmonares em pacientes após AVC e sujeitos saudáveis

O Acidente Vascular Cerebral (AVC) é uma síndrome clínica caracterizada por uma perturbação focal da função cerebral. Geralmente ocasiona quadro de disfunção motora acompanhada de prejuízo da função respiratória. Tendo em vista tal quadro e suas possíveis repercussões, a fisioterapia respiratória tem sido amplamente requisitada com o intuito reverter ou minimizar as complicações. Dentre os recursos utilizados para este fim, os espirômetros de incentivo são utilizados com o objetivo de restaurar os volumes pulmonares, modificando o padrão respiratório e de ventilação pulmonar, prevenindo a incidência das complicações pulmonares. O objetivo do presente estudo foi comparar o desempenho na realização da espirometria de incentivo volume-orientada (EI) e seus efeitos agudos sobre os volumes pulmonares em pacientes após AVC e sujeitos saudáveis. Foram selecionados 40 voluntários, de ambos os gêneros, divididos em grupo experimental (GE), composto por 20 pacientes após AVC e grupo controle (GC) composto por 20 sujeitos saudáveis, pareados quanto à idade, gênero e Índice de Massa Corpórea (IMC). A coleta dos dados foi realizada em duas etapas: (1) Avaliação cognitiva e neurofuncional (Mini Exame do Estado Mental, National Institute Stroke Scale, Medida de Independência Funcional, teste de desempenho da aprendizagem) (2) Avaliação Respiratória (espirometria, manovacuometria e cinemática tóraco-abdominal, através da Pletismografia Opto-eletrônica). A análise estatística foi realizada através do software Graphpad Prism 4.0, em que foram utilizados os testes t Student e ANOVA two-way para comparação intergrupos e adotado nível de significância de 5%. Os resultados mostraram que os pacientes apresentam desempenho inferior na aprendizagem da espirometria de incentivo, com uma média de erros maior 2,95 ± 1,39, quando comparados aos sujeitos saudáveis, 1,15 ± 0,98. Em relação à prática observacional utilizada não foi encontrada diferença entre a aprendizagem através do vídeo ou do terapeuta. Em relação aos efeitos agudos da espirometria de incentivo volume-orientada, os pacientes após AVC apresentaram valores de volume corrente 24,7%, 18% e 14,7% inferiores quando comparados aos sujeitos saudáveis nos momentos pré-EI, EI e pós-EI, porém a espirometria de incentivo induziu incrementos de volume similares em ambos os grupos estudados, com 75, 3% para os pacientes e 73,3% para os sujeitos saudáveis. A espirometria de incentivo promove ganhos significativos no volume corrente da parede torácica, tanto em pacientes acometidos por AVC como em sujeitos saudáveis, no entanto o desempenho da aprendizagem é inferior para os pacientes, para ambas as práticas com vídeo ou terapeuta

Influência da adição de carga na marcha em esteira de crianças com paralisia cerebral hemiparética espástica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Caracterização da dinâmica ambiental da região costeira do município de Galinhos, litoral setentrional do Rio Grande do Norte

This doctorate thesis concerning on the Characterization of the Environmental Dynamics of the Coastal Area of the Municipal district of Galinhos, Septentrional Coast of Rio Grande do Norte State, is located in the influence area of the Guamaré Petroliferous Pole, having as general objective the understanding of the active coastal dynamics in the region of Galinhos, whose specific objectives were: To study the variation of the coast line in the decades of 1954, 1967,1988, 1996, 2000, from remote sensing products; To elucidate the hypothesis of the region of Galinhos to have been an old system of islands barriers, using as basic tool the penetration radar in the soil - GPR; To monitor and to characterize the coastal dynamics of the study area starting from monthly data of beach profiles, sedimentological analysis, hydrodynamic data and environmental characterization data; which were used to feed the database of the N-NE network of Environmental Monitoring of Areas under Influence of the Petroliferous Industry;(REDE05/FINEP/CNPq/CTPETRO/ PETROBRAS). This research is justified, of the environmental point of view, by involving the mangrove ecosystem considered one of the most delicated environments of the State. From the viewpoint of the petroleum exploration, the systems of islands barriers are favorable for hydrocarbons reservoirs and, consequently important targets to the oil and gas industry, becoming this region attractive in comparison with similar lithified environments. With the results of the variability study in the position of the coast line in the Municipal district of Galinhos/RN from the analysis of remote sensing images, it was possible to investigate the changes in the coast line in temporal scale; the use of directional filters allowed to emphasize linings in the direction NE and to identify submerged features such as sandwaves. The use of GPR enabled the confirmation of paleochannels existence and thus confirmed the hypothesis that the Galinhos spit was formed from an old system of islands barriers. The results of the granulometric analyses indicated that in the summer period the sediments in the profiles A and B in the foreshore portion were classified with the granulometry of sand with scattered gravel and in the shoreface were constituted by sand, but in the winter period these same morphologic compartments were constituted by sand with sparse gravel and siltic sand respectively. In the profile C, in the summer and in the winter, the shoreface and foreshore compartments presented predominantly constituted by sand with sparse gravel. The hydrodynamic results showed that the largest wave heights were registered in the month of February (62 cm) and the highest period of 1,00 m/s in the month of May, the sense of the coastal currents was kept among the quadrants SW and NW, and the winds coming from NE were predominant. The analysis of the beach profiles demonstrated that in the profile A, although it had occurred erosion and deposition during the monitored months, the morphology of the referred profile was kept constant. In the profiles B and C, there were abrupt changes in the morphology, during the monitored months, having been identified a cyclic pattern in the features of the foreshore zone sometimes forming longitudinal sandy bars and in other times forming berm. These results evidenced, therefore, that studies of this nature are of fundamental importance for the coastal zoning, aiming subsidies to the organs managers in the closing of decisions as for the implantation of enterprises in the area, and for the industry of the petroleum through generation of information that subsidize the implementation and location of petroliferous structures adequate to this environment

Termodinâmica de um gás de fótons no contexto de eletrodinâmicas não-lineares

The objective of this dissertation is the development of a general formalism to analyze the thermodynamical properties of a photon gas under the context of nonlinear electrodynamics (NLED). To this end it is obtained, through the systematic analysis of Maxwell s electromagnetism (EM) properties, the general dependence of the Lagrangian that describes this kind of theories. From this Lagrangian and in the background of classical field theory, we derive the general dispersion relation that photons must obey in terms of a background field and the NLED properties. It is important to note that, in order to achieve this result, an aproximation has been made in order to allow the separation of the total electromagnetic field into a strong background electromagnetic field and a perturbation. Once the dispersion relation is in hand, the usual Bose-Einstein statistical procedure is followed through which the thermodynamical properties, energy density and pressure relations are obtained. An important result of this work is the fact that equation of state remains identical to the one obtained under EM. Then, two examples are made where the thermodynamic properties are explicitly derived in the context of two NLED, Born-Infelds and a quadratic approximation. The choice of the first one is due to the vast appearance in literature and, the second one, because it is a first order approximation of a large class of NLED. Ultimately, both are chosen because of their simplicity. Finally, the results are compared to EM and interpreted, suggesting possible tests to verify the internal consistency of NLED and motivating further developement into the formalism s quantum case

Estudo da estrutura subsuperficial da província Borborema com correlação de ruído sísmico

Ambient seismic noise has traditionally been considered as an unwanted perturbation in seismic data acquisition that "contaminates" the clean recording of earthquakes. Over the last decade, however, it has been demonstrated that consistent information about the subsurface structure can be extracted from cross-correlation of ambient seismic noise. In this context, the rules are reversed: the ambient seismic noise becomes the desired seismic signal, while earthquakes become the unwanted perturbation that needs to be removed. At periods lower than 30 s, the spectrum of ambient seismic noise is dominated by microseism, which originates from distant atmospheric perturbations over the oceans. The microsseism is the most continuous seismic signal and can be classified as primary – when observed in the range 10-20 s – and secondary – when observed in the range 5-10 s. The Green‘s function of the propagating medium between two receivers (seismic stations) can be reconstructed by cross-correlating seismic noise simultaneously recorded at the receivers. The reconstruction of the Green‘s function is generally proportional to the surface-wave portion of the seismic wavefield, as microsseismic energy travels mostly as surface-waves. In this work, 194 Green‘s functions obtained from stacking of one month of daily cross-correlations of ambient seismic noise recorded in the vertical component of several pairs of broadband seismic stations in Northeast Brazil are presented. The daily cross-correlations were stacked using a timefrequency, phase-weighted scheme that enhances weak coherent signals by reducing incoherent noise. The cross-correlations show that, as expected, the emerged signal is dominated by Rayleigh waves, with dispersion velocities being reliably measured for periods ranging between 5 and 20 s. Both permanent stations from a monitoring seismic network and temporary stations from past passive experiments in the region are considered, resulting in a combined network of 33 stations separated by distances between 60 and 1311 km, approximately. The Rayleigh-wave, dispersion velocity measurements are then used to develop tomographic images of group velocity variation for the Borborema Province of Northeast Brazil. The tomographic maps allow to satisfactorily map buried structural features in the region. At short periods (~5 s) the images reflect shallow crustal structure, clearly delineating intra-continental and marginal sedimentary basins, as well as portions of important shear zones traversing the Borborema Province. At longer periods (10 – 20 s) the images are sensitive to deeper structure in the upper crust, and most of the shallower anomalies fade away. Interestingly, some of them do persist. The deep anomalies do not correlate with either the location of Cenozoic volcanism and uplift - which marked the evolution of the Borborema Province in the Cenozoic - or available maps of surface heat-flow, and the origin of the deep anomalies remains enigmatic.

O político nas imagens de A missão de Heiner Müller e O homem que era uma fábrica de Augusto Boal

Augusto Boal (Brasil) y Heiner Müller (Alemania) son dramaturgos del siglo XX que vivieron en países y contextos evidentemente distintos. Sin embargo, con la crisis del teatro burgués y de las condiciones de legitimidad del régimen de producción de este teatro, ambos presentan puntos de contacto en sus líneas y vectores teatrales que, frente a la universalidad cuestionable de la dramatización, llevan a la concepción de un teatro múltiple y perturbador del orden de lo sensible. Los procesos de escenificación contemporánea exige un adelantamiento del sentido político, desviando del juego de representaciones sociales, para dar lugar al trabajo deconstructor de imágenes como cisión entre la palabra y lo representado, entre lo legible y lo visible. Frente al expuesto, las escritas escénicas y, por eso, literarias de estos autores, sitios de singularización – no con ausencia de paradojas – capaces de movilizar manifestaciones e impases cuanto a las imágenes que ordenan o desordenan los textos dramáticos, traen para la contemporaneidad tensiones que llevan al teatro mismo, tanto a interpelarse como, en su fuerza plural, a encontrar pasajes para el nuevo. Llevar a la superficie aspectos políticos en las imágenes de los textos dramáticos, considerándolos en su inscripción literaria: “La misión: recuerdos de una revolución”, de Heiner Müller, y de “El hombre que era una fábrica”, de Augusto Boal, se hace un desafío, una vez que las imágenes pretendidas son aquellas con formas o materialidades todavía no visibles en la escena, podríamos decir, en estado virtual. Como imágenes pensantes, ellas suceden en el plan de inmanencia del lenguaje (Deleuze y Guattari). Siendo lo “político” una perturbación en lo sensible, contrario a la política (Rancière), la dramaturgia se abala en multiplicidades, desplazando y desnaturalizando las funciones de autor/dramaturgo y lector/actor, teatro/literatura. Dramaturgia simultánea, imagen, fragmento y colaje se muestran como procedimientos artísticos y literarios creativos que se encuentran apropiados sea en la teoría del teatro del oprimido (Boal), sea en el teatro pos-dramático (Hans-ThiesLehmann), a pesar de que, al confrontarlas, sobresalían en desentendimientos: la primera coincide con la lógica de la identidad y la segunda, esta se desarticula, movida por la diáfora, contestación, o desacuerdo. Tales relaciones – no apriorísticas – se suceden en cuanto acontecimiento de la lectura o de la literatura como acontecimiento en que lo político en las imágenes se da, antes, en las lagunas y obscuridades, aludiendo a lo que está más allá de lo sentido, de la escena del gesto y de la palabra. El lector no se para para atribuir sentido, se interroga frente a las metamorfosis y formas oblicuas de acontecimientos insospechables que componen lo político estableciendo la gestión colectiva de la enunciación. En este caso, el texto de Boal y el texto de Müller se inscriben en la producción de una literatura menor, o de un teatro menor, o que los califica como agentes de devenires revolucionarios, agitando, a través de la política en las imágenes, e irrumpiendo contra el problema del poder en las artes.