832 resultados para Geração de corrente


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

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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

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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.

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The rural electrification is characterized by geographical dispersion of the population, low consumption, high investment by consumers and high cost. Moreover, solar radiation constitutes an inexhaustible source of energy and in its conversion into electricity photovoltaic panels are used. In this study, equations were adjusted to field conditions presented by the manufacturer for current and power of small photovoltaic systems. The mathematical analysis was performed on the photovoltaic rural system I- 100 from ISOFOTON, with power 300 Wp, located at the Experimental Farm Lageado of FCA/UNESP. For the development of such equations, the circuitry of photovoltaic cells has been studied to apply iterative numerical methods for the determination of electrical parameters and possible errors in the appropriate equations in the literature to reality. Therefore, a simulation of a photovoltaic panel was proposed through mathematical equations that were adjusted according to the data of local radiation. The results have presented equations that provide real answers to the user and may assist in the design of these systems, once calculated that the maximum power limit ensures a supply of energy generated. This real sizing helps establishing the possible applications of solar energy to the rural producer and informing the real possibilities of generating electricity from the sun.

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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

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

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Mestrado em Métodos Matemáticos para Gestão de Empresas

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The production of water has become one of the most important wastes in the petroleum industry, specifically in the up stream segment. The treatment of this kind of effluents is complex and normally requires high costs. In this context, the electrochemical treatment emerges as an alternative methodology for treating the wastewaters. It employs electrochemical reactions to increase the capability and efficiency of the traditional chemical treatments for associated produced water. The use of electrochemical reactors can be effective with small changes in traditional treatments, generally not representing a significant additional surface area for new equipments (due to the high cost of square meter on offshore platforms) and also it can use almost the same equipments, in continuous or batch flow, without others high costs investments. Electrochemical treatment causes low environmental impact, because the process uses electrons as reagent and generates small amount of wastes. In this work, it was studied two types of electrochemical reactors: eletroflocculation and eletroflotation, with the aim of removing of Cu2+, Zn2+, phenol and BTEX mixture of produced water. In eletroflocculation, an electrical potential was applied to an aqueous solution containing NaCl. For this, it was used iron electrodes, which promote the dissolution of metal ions, generating Fe2+ and gases which, in appropriate pH, promote also clotting-flocculation reactions, removing Cu2+ and Zn2+. In eletroflotation, a carbon steel cathode and a DSA type anode (Ti/TiO2-RuO2-SnO2) were used in a NaCl solution. It was applied an electrical current, producing strong oxidant agents as Cl2 and HOCl, increasing the degradation rate of BTEX and phenol. Under different flow rates, the Zn2+ was removed by electrodeposition or by ZnOH formation, due the increasing of pH during the reaction. To better understand the electrochemical process, a statistical protocol factor (22) with central point was conducted to analyze the sensitivity of operating parameters on removing Zn2+ by eletroflotation, confirming that the current density affected the process negatively and the flow rate positively. For economical viability of these two electrochemical treatments, the energy consumption was calculated, taking in account the kWh given by ANEEL. The treatment cost obtained were quite attractive in comparison with the current treatments used in Rio Grande do Norte state. In addition, it could still be reduced for the case of using other alternative energy source such as solar, wind or gas generated directly from the Petrochemical Plant or offshore platforms

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The thermoelectric energy conversion can be performed directly on generators without moving parts, using the principle of SEEBECK effect, obtained in junctions of drivers' thermocouples and most recently in semiconductor junctions type p-n which have increased efficiency of conversion. When termogenerators are exposed to the temperature difference (thermal gradient) eletromotriz a force is generated inducing the appearance of an electric current in the circuit. Thus, it is possible to convert the heat of combustion of a gas through a burner in power, being a thermoelectric generator. The development of infrared burners, using porous ceramic plate, is possible to improve the efficiency of heating, and reduce harmful emissions such as CO, CO2, NOx, etc.. In recent years the meliorate of thermoelectric modules semiconductor (TEG's) has stimulated the development of devices generating and recovery of thermal irreversibility of thermal machines and processes, improving energy efficiency and exergy these systems, especially processes that enable the cogeneration of energy. This work is based on the construction and evaluation of a prototype in a pilot scale, for energy generation to specific applications. The unit uses a fuel gas (LPG) as a primary energy source. The prototype consists of a porous plate burner infrared, an adapter to the module generator, a set of semiconductor modules purchased from Hi-Z Inc. and a heat exchanger to be used as cold source. The prototype was mounted on a test bench, using a system of acquisition of temperature, a system of application of load and instrumentation to assess its functioning and performance. The prototype had an efficiency of chemical conversion of 0.31% for electrical and heat recovery for cogeneration of about 33.2%, resulting in an overall efficiency of 33.51%. The efficiency of energy exergy next shows that the use of primary energy to useful fuel was satisfactory, although the proposed mechanism has also has a low performance due to underuse of the area heated by the small number of modules, as well as a thermal gradient below the ideal informed by the manufacturer, and other factors. The test methodology adopted proved to be suitable for evaluating the prototype

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In questa tesi vengono analizzati i principi fisici che stanno alla base dei dispositivi ottici di misura di tensioni e di correnti e, in particolare, vengono presentate le differenti soluzioni tecnologiche investigate dai produttori. La trattazione si concentra principalmente sulle tecniche di misura polarimetriche, che riguardano mutamenti indotti nello stato di polarizzazione della luce, mentre essa viaggia attraverso una fibra ottica, a causa di fenomeni esterni di interesse (come campi magnetici o elettrici). Le tecniche ottiche di misura, in futuro, avranno ruoli sempre più predominanti nel settore della fornitura di energia elettrica, dove offrono miglioramenti in sensibilità e prestazioni, rispetto ai convenzionali sistemi, riducendo inoltre i costi grazie alla minima richiesta di isolamento. Esistono, però, ancora dei problemi da risolvere come l'influenza della temperatura ambientale nella misura o l'affidabilità dei dispositivi per lunghi funzionamenti.

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1998