Proposição de um modelo para análise de fluxo de carga, curto-circuito e simulação de relés de produção

The objective of the present work is develop a model to simulate electrical energy networks in transient and stead states, using the software ATP (Alternative Transient Program), able to be a way to join two distinct themes, present in classical methodology planning networks: short circuit analysis and load flow theory. Beyond that, using a tool for relay simulation, this paper intend to use the new developed model to investigate the influence of transient phenomenon in operation of protection relays, and calibrate the enterprise's protections relays. For testing the model, some relays, actually, installed at COSERN were used

Modelagem linear e identificação do modelo dinâmico de um robô móvel com acionamento diferencial

This work presents a modelling and identification method for a wheeled mobile robot, including the actuator dynamics. Instead of the classic modelling approach, where the robot position coordinates (x,y) are utilized as state variables (resulting in a non linear model), the proposed discrete model is based on the travelled distance increment Delta_l. Thus, the resulting model is linear and time invariant and it can be identified through classical methods such as Recursive Least Mean Squares. This approach has a problem: Delta_l can not be directly measured. In this paper, this problem is solved using an estimate of Delta_l based on a second order polynomial approximation. Experimental data were colected and the proposed method was used to identify the model of a real robot

História da ciência como estratégia didática no ensino médio: um breve olhar de conteúdos da óptica

From a critique of aspects of the current teaching of physics, we propose in this paper an investigation into the conceptions of Nature of Science (NOS) submitted by students from the high school level, as well as the inclusion of discussions about some elements of NOS, through the History and Philosophy of Science, understanding them as facilitating strategy for more effective learning of Physics and, more specifically, the contents of optics. Based on the historical period corresponding to Greek antiquity to the mid-nineteenth century, built and applied a teaching unit to a high school class at the Federal Institute of Education, Science and Technology of Rio Grande do Norte (IFRN) Ipanguaçu campus. Our teaching unit involved the reading and interpretation of texts with historical content, observation and assembling five experimental activities, among other activities. Data analysis occurred through questionnaires investigative applied before and after the completion of the teaching unit, as well as questionnaires for content present in the texts. Although not significant, the results indicated that the application of the teaching unit allowed the (re) construction of some conceptions about NOS targets students present in our work, and contribute to a better learning content and greater optical science approach and its nature

Utilizando as ciências espaciais e a astronáutica na construção de atividades práticas em ensino de física

In this work we consider the use of new technologies fron the Space Science and Astronautical, in the learning process, incorporating technical and conceptions of physics Spatial what can take on the response of some problems what there are a lot insistent in populate the mind of professors and followers regarding agreement of these conceptions into the level Average. Intending to bring another contribution to Physics teaching practice, especially Classical Mechanics, but introducing many introductory concepts from Modern Physics, since this topic is considered of great interest for teachers and students, for it involves high technology. It s advanced manufacturing demand certain processes that make possible the application of those concepts

Helena de Machado de Assis; Imagens literárias e a retórica da morte da nação inconclusa

Helena is the romance of perishable and discontinuous title character denominator of a dialectic that does not consume and build the narrative by sequential fragmentation combined with episodic frame. The novel is a lightning stroke to the romantic literary project. Therefore, this study aims to find "objective" elements of the novel that would constitute a conception of literary nation proposed by Machado de Assis, as in classical writing, where women are engaged as a metaphor for the nation by a non-cultural heroism, as the example of the Greek myth of Helena, where the feminine represents a mythical image of the nation. The paper's theoretical conception of the history of Walter Benjamin, that is, that is constructed as an allegorical appeal, the conclusions about the disciplinary society of nineteenth century of Michel Foucault, the construction of the nation as a subtle game to remember and forget of Wander Miranda and the rhetoric of death and loss reflected in the speeches of the cultural heritage of José Reginaldo Santos Gonçalves, which allow you to analyze the work permeated by subjectivity and existential conflicts by Machado, who has it arranged in dialectic with the avant-garde literary romanticism and realism. In this relationship with the Greek myth of Helen, explained that characters with the nickname of Helena in Machado's work are not uncommon. As in classical Helena, Machado s Helena uses three rhetorical are the cause of the seizure of the nation. In this game of remembering and forgetting, in the daily plebiscite, Machado draw ideal images that forged our mythical past and commitment to the future. The suffering love of Helena is suffering from failure of the nation which would have led the author to the use of allegorical language, seeking a balance in the chaos generated by the opposition between cruelty and pity widespread view in an area where only left the character's confession guilt for the death. It is a simulacrum of unfinished nation, the space for the game of remembering and forgetting, while the rhetoric of negotiation of our Brazilianness

Medicina filosófica: as relações entre medicina e filosofia na Grécia antiga e em Kant

This work deals with the relationship between medicine and philosophy, which has existed since Antiquity, and will also be discussed here from Kant s perspective. It presents the historical context formed by reciprocal influences of common notions regarding health/disease, balance/justice, and just measure, which are present in the medical discourse as much as in the philosophical one. It considers that Hippocratic medicine emerges from concerns about dietetics, thus creating the link between philosophy and medicine, which is important for our analysis on Kant s contributions to Hippocratic legacy. Taking into account these considerations, the work distinguishes between two aspects which are associated within the dietetics presented by Kant in his work The conflict of the faculties, studied here in the light of his Doctrine of virtue, particularly the duties to oneself in regard the care of one s body and the teleological conception. In this sense, the work indicates the role of Kantian thinking not only to enrich medical dietetics, by lending to it moral value, but also to enrich philosophy by highlighting its therapeutic effects

Eleutheria: a noção de liberdade na ética de Epicuro

Épicure de Samos (341-270 a.C) fut l'un des plus importants penseurs de l'Antiquité. Le philosophe du Jardin, comme il a été connue, aurait écrit au moins 300 volumes. Ayant vécu dans une Grèce sans l'autonomie des temps passés, a vu l'atténuation du sens de liberté (eleutheria) dans le domaine social. En outre, la théorie atomiste que lui précédée et lui a influencée postulais un déterminisme qui avait entraîné la fatalité et l'élimination des eleutheria aussi dans le domaine de la nature (physis). Dans ce contexte, il donne, de la physiología, une forme originale à l'étude de la physis, afin de postuler l'existence du hasard (tychè) agissant dans le monde phisique et de la liberté, dans l‟action humaine. S‟il fait cela, c‟est parce qu‟il croit que être libre est condition du bonheur et celle-ci réside dans le plaisir. Pour cela, Épicure va présenter l'indéterminisme dans le domaine de la physiologie, garantissant l'existence d'un mouvement de déclinaison de l'atome - le parênklisis. Ainsi, dans ce travail, nous allons effectuer une analyse de la façon de se montrer le sens d‟eleutheria développé dans la pensée de ce maître et comment il interagit avec son projet d'éthique. En particulier, nous discutons de comment, de la physiología, Épicure pense un éthos-llibre tourné vers la réalisation du plaisir, de la vie heureuse. Pour cela, nous utilisons la Lettre à Hérodote, la Lettre à Pítocles, la Lettre à Ménécée, 81 Sentences Vaticanes, 40 Maximes Fondamentales et les rapports doxographie

Agostinho e o ceticismo: um estudo da crítica agostiniana ao ceticismo em Contra Acadêmicos

The assent of the Truth: here's a formula that seems to have puzzled philosophers since antiquity. The possibility of apprehending truth was defended by some philosophers who have been called dogmatic, due to their haste to judge appearances as representations of reality, and refuted by those who chose to continue questioning rather than engage with his predicament. These thinkers were called skeptics. Among those who defended the consent of the truth, is highlighted by St. Augustine in this research, which aims to combat the widespread skepticism in the ancient doctrine of the Academy of Plato in his work Against Academicos. Thus, to conduct this research we ask: What are the main arguments made by St. Augustine against the scholarly skepticism? In order to address the problem identified, we propose to investigate the critical skepticism of St. Augustine, identifying and analyzing the main rebuttals he built. For this purpose, we conducted a survey of aspects of both the skepticism about the life and thought of St. Augustine about this doctrine

A metafísica de Isaac Newton

The general objective of this dissertation is to analyze the metaphysical aspects of "rational mechanics" of Isaac Newton, clarifying, by scientific and philosophical discourse, their main elements, with emphasis to the presence of one entity infinitely rational behind all the phenomena of nature, and to the Newton's insight as certain empiricist which, however, accepts deductions metaphysics; a philosopher-scientist. The specific objectives are detailed below: a) brief presentation of the development of modern science, since the Pre-Socratics, seeking to understand the historical conjecture that enabled the rise of Newtonian mechanics; b) presentation of the elements of scientific methodology and philosophical, aimed at comprehension of certain "Newtonian methodology", understanding how this specific methodology able to present empirical aspects, mathematics, philosophic and religious in communion; c) to understand, from the Newtonian concepts, both concerning man's role in the world as the "notional notions" of mass, space, time and movement, necessary for analysis and understanding of certain metaphysical aspects in the Newtonian physics; d) to present the Newtonian concepts related to the ether, to understand why it necessarily assumes metaphysics characteristics and mediation between the bodies; e) to present and understand the factors that lead the empiricist Newton to assume the religion in his mechanics, as well as, the existence and functions of God in nature, to object to the higher content of his metaphysics; f) to highlight the metaphysical elements of his classical mechanics, that confirm the presence of concepts like God Creator and Preserver of the natural laws; g) at last, to analyze the importance of Newton to the modern metaphysics and the legacy to philosophy of science at sec. XVII to science contemporary

Nietzsche e a modernidade: da crítica à metafísica à crítica à democracia

This dissertation presents an interpretation concerning the critical considerations of the German philosopher Friedrich Nietzsche on Modernity, especially Nietzsche s criticism of Modernity, of Christian mores and democracy produced by him in Beyond Good and Evil. Nietzsche attentively analyses details of Modernity, produces a diagnosis of modern man and discovers the sign of decay. We consider that Nietzsche s criticism of modernity is directly linked to the criticism of classic metaphysics. We emphasize questions like: what in us aspires to truth? Christian mores: why and what for? What characterizes modernity? Could it be the appeal to the democratic taste? Is it possible to reinvent Modernity? We stress the relation between the notion of truth, democracy and Christian mores, showing that these mores were also inherited from the Socratic culture. We also intend to clarify Nietzsche s proposal of a new way of doing philosophy, that would be able to surpass the decay which rules in European modern culture. The end of this research points out to the ―philosophers of the future‖ who are able, according to Nietzsche, to claim life beyond the metaphysics opposition, beyond the good and the evil

Fundamentos da filosofia moral de Peter Singer

This research aims to reconstruct and explain the argument proposed by Peter Singer to justify the principle of equal consideration of interests (PECI). The PECI is the basic normative principle according to people should consider the interests of all sentient beings affected when somebody taking a moral decision. It is the join that Singer proposes between universalizability and the principle of equal consideration of interests that constitutes a compelling reason to justify it. The universalizability requires to disregard the numerical differences, putting yourself in other people s shoes, and to consider preferences, interests, desires and ideals of those affected. Singer joins universalizability to normative principle and molds the form and content of his theory. The first chapter introduces the discussion will be developed in this essay. The second chapter deals the historical and philosophical viewpoint from which Singer starts his studies. The third chapter is about the Singer s critiques of naturalism, intuitionism, relativism, simple subjectivism and emotivism. The fourth chapter exposes the design of universal prescriptivism proposed by R. M. Hare. The universal prescriptivism indicates, in the Singer s viewpoint, a consistent way to create the join between the universalizability and PECI. It highlights also the criticism designed by J. L. Mackie and Singer himself to universal prescriptivism. The second part of this chapter shows briefly some of the main points of the classical conception of utilitarianism and its possible relationship with the theory of Singer. The fifth chapter introduces the Singer s thesis about the origin of ethics and the universalizability as a feature necessary to the point of view of ethic, and the way which this argument is developed to form the PECI. The sixth chapter exposes the main distinctions that characterize the PECI. Finally the seventh chapter provides a discussion about the reasons highlighted by Singer for one who wants orient his life according to the standpoint of ethics. This structure allows explaining the main ideas of the author concerning the theoretical foundations of his moral philosophy

Filtros acústicos em cristais fonônicos

In this work, we have studied the acoustic phonon wave propagation within the periodic and quasiperiodic superlattices of Fibonacci type. These structures are formed by phononic crystals, whose periodicity allows the raise of regions known as stop bands, which prevent the phonon propagation throughout the structure for specific frequency values. This phenomenon allows the construction of acoustic filters with great technological potential. Our theoretical model were based on the method of the transfer matrix, thery acoustics phonons which describes the propagation of the transverse and longitudinal modes within a unit cell, linking them with the precedent cell in the multilayer structure. The transfer matrix is built taking into account the elastic and electromagnetic boundary conditions in the superllatice interfaces, and it is related to the coupled differential equation solutions (elastic and electromagnetic) that describe each model under consideration. We investigated the piezoelectric properties of GaN and AlN the nitride semiconductors, whose properties are important to applications in the semiconductor device industry. The calculations that characterize the piezoelectric system, depend strongly on the cubic (zinc-bend) and hexagonal (wurtzite) crystal symmetries, that are described the elastic and piezoelectric tensors. The investigation of the liquid Hg (mercury), Ga (gallium) and Ar (argon) systems in static conditions also using the classical theory of elasticity. Together with the Euler s equation of fluid mechanics they one solved to the solid/liquid and the liquid/liquid interfaces to obtain and discuss several interesting physical results. In particular, the acoustical filters obtained from these structures are again presented and their features discussed

Um estudo na teoria do movimento brownianno com viscosidade variável

In this work we investigate the stochastic behavior of a large class of systems with variable damping which are described by a time-dependent Lagrangian. Our stochastic approach is based on the Langevin treatment describing the motion of a classical Brownian particle of mass m. Two situations of physical interest are considered. In the first one, we discuss in detail an application of the standard Langevin treatment (white noise) for the variable damping system. In the second one, a more general viewpoint is adopted by assuming a given expression to the so-called collored noise. For both cases, the basic diffententiaql equations are analytically solved and al the quantities physically relevant are explicitly determined. The results depend on an arbitrary q parameter measuring how the behavior of the system departs from the standard brownian particle with constant viscosity. Several types of sthocastic behavior (superdiffusive and subdiffusive) are obteinded when the free pamameter varies continuosly. However, all the results of the conventional Langevin approach with constant damping are recovered in the limit q = 1

Estudos de modelos Estocásticos: processo de contato, séries aleatórias e processos difusivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Montagem e construção de um magnetômetro a efeito Kerr magneto-óptico

n this master s dissertation a Kerr Magneto Optic s magnetometer effect was set up to do characterization of samples type films fine and ultra thin, these samples will be grown after the implementation of the sputtering technique at the magnetism laboratory of of this department. In this work a cooled electromagnet was also built the water and that it reaches close values to 10kOe with a gap of 22 mm including an area of uniform field of 25mm of diameter. The first chapter treats of the construction of this electromagnet from its dimensioning to the operation tests that involve measures of reached maximum field and temperature of the reels when operated during one hour. The second chapter is dedicated to the revision of the magnetism and the magnetization processes as well as it presents a theoretical base regarding the magnetic energies found in films and magnetic multilayer. In the sequence, the third chapter, is especially dedicated the description of the effects magneto opticians the effect kerr in the longitudinal, traverse and polar configurations, using for so much only the classic approach of the electromagnetism and the coefficients of Fresnel. Distinguished the two areas of observation of the effect regarding thickness of the film. The constructive aspects of the experimental apparatus as well as the details of its operation are explained at the room surrender, also presenting the preliminary results of the measures made in one serializes of permalloy films and concluding with the results of the characterization of the first films of iron and permalloy grown here at the theoretical and experimental physics department at UFRN