1000 resultados para Athena


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In this graduate work we will perform the dimensional reduction of particles of spin s=0, s=1 and s=2 via Kaluza Klein mechanism. The method of Kaluza-Klein dimensional reduction is introduced by the dimensional reduction from D to D

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Ce document présente l'analyse de la qualité de l'énergie dans une centrale solaire photovoltaïque - avec une capacité installée de 1 MWpico, relié au réseau de distribution d’électricité en 11,9 kV, qui a comme but connaître et également de comparer à la norme nationale actuelle, les effets de la qualité de l'énergie électrique résultant de l'utilisation de cette type matrice génératrice. Le rapport a été basé sur des niveaux spécifiés dans le module 8 des Procédures de distribution d'électricité dans le réseau national d'électricité - PRODIST, qui précise les directrices sur la question de la qualité de l'énergie électrique sur le territoire brésilien. Il a été considéré aussi les recommandations internationales 929 et 1547, qui proposent des pratiques recommandées concernant des systèmes de génération de l'énergie solaire PV (photovoltaïque), et également des normes pour le raccordement de ces types de sources au réseau de distributions d'électricité, tous deux établis par l'Institut des ingénieurs électriciens et électroniciens, largement connu comme IEEE. Le développement et le travail sur le terrain a eu lieu de manière continué, et non dans des moments spécifiques, assurant de cette manière, la fiabilité des données obtenues

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In this work we make an introduction to Lattice Gauge Theory, focusing on the Elitzur Theorem about the expected value of not gauge invariant local observables. Finally, after the exposure of the main facts of the theory, we make an extension to semilocal models

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Distribution networks are formed by long lines that carry electricity substations to homes and industries. These lines have associated impedance and depending on operating conditions of the network these impedances may vary. This paper provides a detailed analysis of the effects observed in studies of voltage drop, short circuit and electrical losses, when considered the drivers sequence impedances used in primary distribution network at different temperatures. Therefore, it is initially presented a calculation methodology and details the factors that influence the final values. The methodology presented tackles in a practical way the main factors that directly or indirectly influence the values of the impedances as an emblematic example and will be properly dealt with throughout the paper is the effect of temperature on the values of the sequence impedances. More specifically is dealt with the case of XLPE cables protected, by having a higher maximum operating temperature than the operating temperature of the network. The effects observed in the power flow generated when considering the impedance values at both temperatures were analyzed. The impedance drivers tend to increase with increasing temperature. Thus the impedance of the conductor XLPE protected will tend to be greater for the maximum operating temperature for which the operating temperature of the network, resulting in greater voltage drop and higher electrical losses

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In this work we have developed an apparatus in order to study the capture of asteroids by planets surrounded by a gas envelope during y-by, to do this we have brought an innovation by using a hydrodynamical gas. We began such project by studying particles trajectories with a code based on the analytical gas. After being used to this model we have started a process to elaborate a code which uses the gas in a numerical way. The hydrodynamical gas is described by equations which are not solved analytically. Therefore, it was used an algorithm able to model the gas by keeping all information of the gas in cells. Thus we have made a code to read such cell`s information and then to solve all calculations. Once this process is done, the program inform us all date about the simulated trajectories

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This work consists of a semiotic analysis of the animation motion picture The Lion King (1994), by the Walt Disney Animation Studios, describing its intertextual relation with Hamlet, by Shakespeare, considering Disney’s individuality, its style. In order to study style in texts, we use discursive semiotics theory, highlighting Discini’s work (2013) and the concept of discursive settings. Hence, a deep discussion about The Lion King’s style, compared to the Shakespeare’s play, is established. The movie, once a syncretic text, requires advanced studies on Expression Plane, its plastic, musical and verbal/phonic aspects. We find these studies in the work of José Luiz Fiorin (2009), Lúcia Teixeira (2009), Ana Claúdia de Oliveira (2009), Jean-Marie Floch (2009) and Antônio Vicente Pietroforte (2008). We note how a syncretic text makes the discursive settings more complex by assembling plastic and sonorous materials in semissimbolic relation. Once defined The Lion King’s style, we analyze the way it justifies the intense popularity of this kind of animation features. Finally, it is important to understand how Disney uses in its style not only discursive settings, but also passional settings, revealing its own way to stir emotions on the spectator

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Introduces technical, economic and environmentally competitive solutions in the energy market is a great challenge for society. This work examines each of these aspects considering the production of electrolytic hydrogen with energy from wind power, solar and hydropower, in order to ensure an overview of this energy carrier. Initially, an assessment of the technical aspects is made addressing existing electrolysers technologies, its main characteristics and differences. The geographical distribution of wind, solar and hydroelectric potential in Brazil is also mapped, and a configuration scheme of a hydrogen production system is discussed. Subsequently, the economic analysis calculates the cost of investment in the alkaline electrolyser of 60 Nm³ / h, similar to the Brazilian bus powered by hydrogen project, coordinated by EMTU. Since the main input of electrolysis is electricity, is analyzed the latest energy auctions of each primary source and it is calculated the cost of production of the wind, solar and hydropower hydrogen. Postponed to this, are investigated the intrinsic environmental impacts of electricity generation process, proposing a readjustment of an indicator of ecological efficiency for the production of hydrogen. Finally, the work discusses the concept of externalities and demonstrates how the incorporation of external costs can leverage the hydrogen economy. In short, it is evident that the wind and hydroelectric hydrogens are more promising compared to solar hydrogen, whether in the economic aspect, because it achieved lower costs, whether in the environmental aspect, because it reached the highest ecological efficiency

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This paper presents a study based on literature and examples found on literature of the potential of petroleum gas to be used as a primary source to generate electricity. The steady increase electricity demand in Brazil makes desirable an effective use of all available primary sources, combined with this need the momentum of the country with the discovery of the presalt reserves becomes interesting the use of this gas, often wasted, for generating electricity. The electricity generation in this work is illustrated by the cogeneration in oil refining plants that have the combined cycle thermal operation. The ultimate goal is to provide a text to identify the advantages, disadvantages and trends of this type of generation

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The automobile industry is increasingly interested in reducing vehicle weight for greater speed, lower fuel consumption and emissions, through innovation of materials and processes. One way to do this is to seek the replacement of conventional processes by the use of structural adhesives. Structural adhesives are highly resistant materials, which can replace rivets, bolts and welds allowing the substrate / adhesive assemble is stronger than the substrate itself. One of the major advantages of gluing with respect to welding is its esthetic appearance, since it does not leave marks. For this reason, parts to be soldered require a minimum thickness so that the marks do not appear, since the pieces from gluing have no restriction as to the thickness. By replacing the vibration welding process for gluing process of the instrument panel parts of an automobile, one obtains a reduction of the thickness of the parts and therefore it decreases the weight of the car. This work aims to study the various structural adhesives that already exist on the market to be applied on the instrument panel. The mechanical test performed to measure the maximum adhesive strength was the Lap Shear Test at 23°C (room temperature), -35°C and 85°C. The types of adhesives used were the hot-melt and the bi-component. By the results obtained, it is in favor using the bi-component for application to the union of instrument panel parts

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The flight quality describes the skills of the pilot realize a given task and its difficulty to perform it. Flight quality criteria provide a valuable reference for the designers during the requirements definitions phase and to develop them during the phase of flight testing. These criteria were taken important for the development of a fly-by-wire system. There are several flight quality criteria and this work analyzes the bandwidth criteria, this is evaluated according to a model an aircraft using the SIMULINK/MATLAB. In addition, the paper also describes in detail what is a flight quality criteria and shows an overview of the bandwidth criteria

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When materials for application in aircraft structural components are studied, it must be considered that they will be submitted to cyclic loading, and this is an important parameter to design the study in fatigue life of the materials. Whereas, for example, a landing gear operation, the study of fatigue life and corrosion in the materials used in it is essential, especially when you want to use new techniques for surface treatments. The objective is to study the influence of surface treatment of immersion ion implantation nitrogen plasma, in axial fatigue of Stainless steel 15-5 PH in 39-42 HRC condition. Stainless steel 15-5 PH was tested in axial fatigue and corrosion in salt spray. It was also performed microindentation tests, optical microscopy for microstructural analysis and scanning electron microscopy for fractographic analysis. It was observed that the 3IP had no effect on the thickness of the material and not the hardness of it, and still provided a significant increase in fatigue life of the material

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Energy efficiency is an increasingly important issue due to the current scenario where increasing demand is growing faster than the energy supplied. It is important, therefore, analyze and minimize electrical system losses. This study conducts a comparison of a system formed by a photovoltaic generator feeding an LED lamp directly without steps DC-AC -DC conversion, and a system using these conversion steps for the same lamp power. Losses in conversion steps are quantified and the degradation of power quality occurred due to conversion is evaluated

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Seeking to meet the requirements: relatively low cost of materials and wide applicability in the automotive industry. The best option was the steel Dual Phase (DP), because that is lighter, have high formability, meet the cost requirements and applicability, steel Dual Phase (DP) came to meet these requirements with its two-phase microstructure, ferrite and martensite microstructure who claim to respect and mechanical properties. In this context, the aim of this study was to correlate the microstructure revealed in metallography to the mechanical properties observed in hardness and tensile tests. The microstructure is revealed by etching in 2% nital and then captured images of the sample were processed in ImageJ software to aid in determining the volume fraction of the phases present. Therefore, the mechanical properties were evaluated with respect to volume fraction of the steel layers and analyzed DP 600 together with the mechanical properties obtained by Rockwell hardness test and tensile test. With the values of the mechanical properties calculated and tested, it was possible to describe the method of metallography, as the attack phase and counts, so that it can use this relationship tested/calculated property as a qualitative analytical tool. The method used for the correlation between the microstructure and mechanical properties confirmed the importance of the phases present in the Dual Phase steel to obtain the desired mechanical properties in the application of the steel