45 resultados para Energia vital

em Universidade Federal do Rio Grande do Norte(UFRN)


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Energy is a vital resource for social and economic development. In the present scenario, the search for alternative energy sources has become fundamental, especially after the oil crises between 1973 and 1979, the Chernobyl nuclear accident in 1986 and the Kyoto Protocol in 1997. The demand for the development of new alternative energy sources aims to complement existing forms allows to meet the demand for energy consumption with greater security. Brazil, with the guideline of not dirtying the energy matrix by the fossil fuels exploitation and the recent energy crisis caused by the lack of rains, directs energy policies for the development of other renewable energy sources, complementing the hydric. This country is one of the countries that stand out for power generation capacity from the winds in several areas, especially Rio Grande do Norte (RN), which is one of the states with highest installed power and great potential to be explored. In this context arises the purpose of this work to identify the incentive to develop policies of wind energy in Rio Grande do Norte. The study was conducted by a qualitative methodology of data analysis called content analysis, oriented for towards message characteristics, its informational value, the words, arguments and ideas expressed in it, constituting a thematic analysis. To collect the data interviews were conducted with managers of major organizations related to wind energy in Brazil and in the state of Rio Grande do Norte. The identification of incentive policies was achieved in three stages: the first seeking incentives policies in national terms, which are applied to all states, the second with the questionnaire application and the third to research and data collection for the development of the installed power of the RN as compared to other states. At the end, the results demonstrated hat in Rio Grande do Norte state there is no incentive policy for the development of wind power set and consolidated, specific actions in order to optimize the bureaucratic issues related to wind farms, especially on environmental issues. The absence of this policy hinders the development of wind energy RN, considering result in reduced competitiveness and performance in recent energy auctions. Among the perceived obstacles include the lack of hand labor sufficient to achieve the reporting and analysis of environmental licenses, the lack of updating the wind Atlas of the state, a shortfall of tax incentives. Added to these difficulties excel barriers in infrastructure and logistics, with the lack of a suitable port for large loads and the need for reform, maintenance and duplication of roads and highways that are still loss-making. It is suggested as future work the relationship of the technology park of energy and the development of wind power in the state, the influence of the technology park to attract businesses and industries in the wind sector to settle in RN and a comparison of incentive policies to development of wind energy in the Brazilian states observing wind development in the same states under study.

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Offshore wind power emits low amounts of gases, is renewable and has better performance than onshore due to its greater stability and higher wind power density, less visual and noise impact, among others. Brazil has a high capacity of generation, but has not yet developed any offshore projects. High costs are a strong impediment. This study is an effort towards pricing offshore resources through Livelized Cost of Energy - LCOE, which represents the minimum return to cover the costs of development, production and maintenance of a wind project. Initially LCOE was calculated for all Brazilian onshore wind farms listed at Bloomberg New Energy Finance R○, accounting for 71 farms. Then hypothetical offshore wind farms were created from the onshore farms, tripling the cost of generation, which is consistent with the literature, and estimating the offshore energy for two locations off the Brazilian coast using satellite data extracted from National Oceanic and Atmospheric Administration. The results demonstrate that offshore resources have the potential to significantly reduce the energy price due to the better performance of the wind at sea

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The Tungsten/copper composites are commonly used for electrical and thermal objectives like heat sinks and lectrical conductors, propitiating an excellent thermal and electrical conductivity. These properties are dependents of the composition, crystallite size and production process. The high energy milling of the powder of W-Cu produces an dispersion high and homogenization levels with crystallite size of W very small in the ductile Cu phase. This work discusses the effect of the HEM in preparation of the W-25Cu composite powders. Three techniques of powder preparation were utilized: milling the dry with powder of thick Cu, milling the dry with powder of fine Cu and milling the wet with powder of thick Cu. The form, size and composition of the particles of the powders milled were observed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) was used to analyse the phases, lattice parameters, size and microstrain of the crystallite. The analyse of the crystalline structure of the W-25Cu powders milled made by Rietveld Method suggests the partial solid solubility of the constituent elements of the Cu in lattice of the W. This analyse shows too that the HEM produces the reduction high on the crystallite size and the increase in the lattice strain of both phases, this is more intense in the phase W

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This work a studied the high energy milling effect in microstructure and magnetic properties of the WC-10wt.%Co composite. The composite powders were prepared by mechanical mixed and milled at 2 hours, 100 hours, 200 hours and 300 hours in planetary milling. After this process the composite were compacted in stainless steel die with cylindrical county of 10 mm of diameter, at pressure 200 Mpa and sintered in a resistive furnace in argon atmosphere at 1400 oC for 5 min. The sintered composite were cutted, inlaid, sandpapered, and polished. The microestrutural parameters of the composite was analyzed by X-ray diffraction, scanning electronic microscopy, optical microscopy, hardness, magnetic propriety and Rietveld method analyze. The results shows, with milling time increase the particle size decrease, it possibility minor temperature of sintering. The increase of milling time caused allotropic transformation in cobalt phase and cold welding between particles. The cold welding caused the formation of the particle composite. The X-ray diffraction pattern of composite powders shows the WC peaks intensity decrease with the milling time increase. The X-ray diffraction pattern of the composite sintered samples shows the other phases. The magnetic measurements detected a significant increase in the coercitive field and a decrease in the saturation magnetization with milling time increase. The increase coercitive field it was also verified with decrease grain size with milling time increase. For the composite powders the increase coercitive field it was verified with particle size reduction and saturation magnetization variation is relate with the variation of free cobalt. The Rietveld method analyze shows at milling time increase the mean crystalline size of WC, and Co-cfc phases in composite sintered sample are higher than in composite powders. The mean crystallite size of Co-hc phase in composite powders is higher than in composite sintered sample. The mean lattice strains of WC, Co-hc and Co-cfc phases in composite powders are higher than in composite sintered samples. The cells parameters of the composite powder decrease at milling time increase this effect came from the particle size reduction at milling time increase. In sintered composite the cells parameters is constant with milling time increase

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In this work, was studied the formation of a composite of the refractory metal niobium with copper, through the process of high-energy milling and liquid phase sintering. The HEM can be used to synthesize composite powders with high homogeneity and fine size particle distribution. It may also produce the solid solubility in immiscible systems such as Nb-Cu, or extend the solubility of systems with limited solubility. Therefore, in the immiscible system Cu-Nb, the high-energy milling was successfully used to obtain the composite powder particles. Initially, the formation of composite particles during the HEM and the effect of preparation technique on the microstructure of the material was evaluated. Four loads of Nb and Cu powders containing 20%wt Cu were synthesized by MAE in a planetary type ball mill under different periods of grinding. The influence of grinding time on the metal particles is evaluated during the process by the withdrawal of samples at intermediate times of milling. After compaction under different forces, the samples were sintered in a vacuum furnace. The liquid phase sintering of these samples prepared by HEM produced a homogeneous and fine grained. The composite particles forming the sintered samples are the addition of a hard phase (Nb) with a high melting point, and a ductile phase (Cu) with low melting point and high thermal and electrical conductivities. Based on these properties, the Nb-Cu system is a potential material for many applications, such as electrical contacts, welding electrodes, coils for generating high magnetic fields, heat sinks and microwave absorbers, which are coupled to electronic devices. The characterization techniques used in this study, were laser granulometry, used to evaluate the homogeneity and particle size, and the X-ray diffraction, in the phase identification and to analyze the crystalline structure of the powders during milling. The morphology and dispersion of the phases in the composite powder particles, as well the microstructures of the sintered samples, were observed by scanning electron microscopy (SEM). Subsequently, the sintered samples are evaluated for density and densification. And finally, they were characterized by techniques of measuring the electrical conductivity and microhardness, whose properties are analyzed as a function of the parameters for obtaining the composite

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Magnetic ceramics have been widely investigated, especially with respect to intrinsic and extrinsic characteristics of these materials. Among the magnetic ceramic materials of technological interest, there are the ferrites. On the other hand, the thermal treatment of ceramic materials by microwave energy has offered various advantages such as: optimization of production processes, high heat control, low consumption of time and energy among others. In this work were synthesized powders of Ni-Zn ferrite with compositions Ni1- xZnxFe2O4 (0.25 ≤ x ≤ 0.75 mols) by the polymeric precursor route in two heat treatment conditions, conventional oven and microwave energy at 500, 650, 800 and 950°C and its structural, and morphological imaging. The materials were characterized by thermal analysis (TG/ DSC), X-ray diffraction (XRD), absorption spectroscopy in the infrared (FTIR), scanning electron microscopy (SEM), X-ray spectroscopy and energy dispersive (EDS) and vibrating sample magnetometry (VSM). The results of X-ray diffraction confirmed the formation of ferrite with spinel-type cubic structure. The extrinsic characteristics of the powders obtained by microwave calcination and influence significantly the magnetic behavior of ferrites, showing particles ferrimagnéticas characterized as soft magnetic materials (soft), is of great technological interest. The results obtained led the potential application of microwave energy for calcining powders of Ni-Zn ferrite

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The aim of the present study was to assess the effectiveness and adverse effects on dental enamel caused by nightguard vital bleaching with 10% carbamide peroxide. This was accomplished through the interaction of researchers from different areas such as dentistry, materials engineering and physics. Fifty volunteers took part in the doubleblind randomized controlled clinical trial. They were allocated to an experimental group that used Opalescence PF 10% (OPA) and a control group that used a placebo gel (PLA). Fragments of human dental enamel from the vestibular surface of healthy premolars, extracted for orthodontic reasons, were fixed to the vestibular surface of the first upper molars of the volunteers for in situ observation. Bleaching was performed at night for 21 days. The observation periods included Baseline (BL), T0 (21 days), T30 (30 days after treatment) and T180 (180 days after treatment, only for the OPA group). Tooth color was assessed by comparing it with the Vita® scale and by the degree of satisfaction expressed by the volunteer. We also assessed adverse clinical effects, dental sensitivity and gingival bleeding. The study of adverse effects on enamel was conducted in vivo and in situ, using the DIAGNOdent® laser fluorescence device to detect mineral loss. Scanning electron microscopy (SEM) was used to check for superficial morphological alterations, energy dispersive spectrophotometry (EDS) to semiquantitatively assess chemical composition using the Ca/P ratio, and the x-ray diffraction (XRD) technique to observe alterations in enamel microstructure. The results showed that nightguard vital bleaching with 10% carbamide peroxide was effective in 96% of the cases, versus 8% for the PLA group. Dental sensitivity was present in 36% (9/25) of the cases. There was no significant association between gingival bleeding and the type of gel used (p = 1.00). In vivo laser fluorescence analysis showed no difference in values for the control group, whereas in the OPA group there was a statistically significant difference between baseline values in relation to the subsequent periods (p<0.01), with lower mean values for post-bleaching times. There was a significant difference between the groups for times T0 and T30. Micrographic analysis showed no enamel surface alterations related to the treatment performed. No significant alteration in Ca/P ratio was observed in the OPA group (p = 0.624) or in the PLA group (p = 0.462) for each of the observation periods, nor between the groups studied (p=0.102). The XRD pattern for both groups showed the presence of three-phase Hydroxyapatite according to JCPDS files (9-0432[Ca5(PO4)3(OH)], 18-0303[Ca3(PO4)2.xH2O] and 25-0166[Ca5(PO4)3(OH, Cl, F)]). No other peak associated to other phases was found, independent of the group analyzed, which reveals there was no disappearance, nucleation or phase transformation. Neither was there any alteration in peak pattern location. With the methodology and protocol used in this study, nightguard vital bleaching with 10% carbamide peroxide proved to be an effective and safe procedure for dental enamel

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The drug targeting has been the subject of extensive studies in order to develop site-specific treatments that minimize side effects and become more effective anticancer therapy. Despite considerable interest in this class, drugs like antibiotics also have limitations, and have been neglected. Using new pharmaceutical technologies, the use of magnetic vectors appear as promising candidate for drug delivery systems in several studies. Small magnetic particles bound to the drug of interest can be modulated according to the orientation of a magnet outside the body, locating and holding in a specific site. In this work, we propose the use of High Energy Milling (HEM) for synthesis of a magnetic vector with characteristics suitable for biomedical applications by intravenous administration, and for the formation of an oxacillin-carrier complex to obtain a system for treating infections caused by Staphylococcus aureus. The results of the variation of milling time showed that the size and structural properties of the formed material change with increasing milling time, and in 60 hours we found the sample closest to the ideal conditions of the material. The vector-drug system was studied in terms of structural stability and antimicrobial activity after the milling process, which revealed the integrity of the oxacillin molecule and its bactericidal action on cultures of Staphylococcus aureus ATCC

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Electrical energy today is an essential element in the life of any human being. Through the access to electrical energy it is possible to enjoy dignified conditions of life, having in mind the possibility of making use of minimal material conditions of life. The lack of access to electricity is directly linked to poverty and degrading conditions of life, in which are some communities in Brazil, especially the more isolated from urban centers. Access to the electric service is a determining factor for the preservation of human dignity, constitutional principle inscribe in the art.1 of the Federal Constitution, and the promotion of development, being a right of everyone and a duty of the State to promote universal access. For that reason, focuses mainly on the analysis of their setting as a fundamental social right and its importance for national development. For this, the theoretical and descriptive method was used, with normative and literary analysis, in particular the Constitution of 1988. This study also discusses the form of action of the State in the energy sector, to give effect to the fundamental social right of access to electricity, the characteristics of public service and the principles that guide it, in addition to the role of public policies in universalization of access, in particular the analysis of the Program Luz para Todos, and the function of regulation in the implementation of these policies and the provision of adequate public services.

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A conformação do desenvolvimento propugnado pela Constituição Federal de 1988 como objetivo fundamental da república, certamente perpassa pela racionalização das questões energéticas e pela diversificação da matriz nacional enquanto estratégia de aprovisionamento. O desenvolvimento energético em toda a sua complexidade deve ser alicerçado não em uma relação de contraposição à sustentabilidade, mas cooperativismo normativo e de projetos sociais que objetivam a melhorias para a população nestes dois seguimentos. O advento das energias renováveis nesse contexto se consolida como uma alternativa viável, apesar do tratamento dado pela Lei Maior ao tema ter sido apenas com relação à geração em pequena escala. A interpretação sistemática dos postulados da ordem econômica e as exigências da sociedade estimulam o aproveitamento dos potenciais renováveis em escala comercial e regional, além do fortalecimento nos segmentos de autoprodução e produção independente. Dentre as energias tratadas como prioritárias neste contexto, a eólica revela-se como carecedora de aprofundamento das estruturas dogmáticas de sua positivação, que envolve um vasto manancial de regras pulverizadas na regulação econômica do setor elétrico e no controle ambiental. Esta textura submete os empreendimentos elioelétricos aos instrumentos da política nacional do meio ambiente e às determinações do poder concedente dos serviços de energia elétrica, responsável pela pormenorização da geração, transmissão, distribuição e comercialização de energia, independentemente da fonte primária utilizada no processo de transformação. Tratar destas questões com o compromisso na formulação de raciocínios críticos e propositivos, especialmente acerca de temas como a liberdade energética e controle de mercado, é imperioso para superar juridicamente as limitações presentes inclusive no discurso da delimitação de marcos normativos adequados. Havendo vantagens ambientais, tecnológicas e comerciais na exploração da energia cinética do vento como propulsora do desenvolvimento no modelo civilizatório estabelecido, cumpre também ao Estado dar a sua contribuição setorial na forma de incentivos, desburocratização e aprimoramento do modelo concorrencial. O estudo adota os métodos histórico-evolutivo, dialético e sistêmico de abordagem, encarando as hipóteses formuladas no aspecto das consequências multilaterais que as soluções encontradas apontam, exigindo que a estabilização de expectativas sociais por parte do ordenamento jurídico não ignorem o sentido material cognitivamente aberto do desenvolvimento. Hodiernamente, a perspectiva de desenvolvimento energético alia tendências econômicas e tecnológicas em favor das fontes alternativas mais eficientes, revelando a energia eólica como uma representante adequada em termos pragmáticos de normatização e preservação ambiental

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A modeling of criterias and alternatives is through and applied a questionnaire based on method AHP to proprietors of gas stations. The considered alternatives had been the maintenance of the current state with electric energy of the deliverer and the generation in small scale based on the natural gas. The used criteria had been Cost of the Investment, Final Cost of the Energy, Operational cost, Ambient Benefits, Risk and Variation of Costs. The study it was carried through in the city of Natal, RN in ranks that make use of the natural as for resale, where the generation alternative on the basis of the available gas is present. The main results evidence in a dimension the viability of use of method AHP with questionnaire by means of validation of the judgments with analysis of variance beyond proper the normal mechanisms of analysis of consistency to the method. The main results of the analysis help to show that in this in case that the profile of models of criteria and judgments of the actors is similar, with the final evidence of that it has a dominance of the maintenance of the energy of the deliverer. The main criterion to influence this decision was the risk

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Meaning fuel and renewal energy source s derivative additives, the term biodiesel exists in Brazil since 1980, when it was signed its first patent by Expedito Parente. Since then, its importance has grown gradually due to the worsening of the ambient problems, since its use has became a highly promising alternative to the pollution decrease, as in the carbon dioxide issue as with the smoke and sulfur oxide. In Brazil, it was created the National Program of Production, whose objective is to insert the new product in the country s energy matrix, strengthening the economy and creating new employment opportunities, being an important product to the national energetic independence, since Brazil still imports diesel to its domestic consumption. This study aims to identify the ambient, social and economic perception of the teachers from the Technology Center of Natal city (CTGÁS-RN) to the biodiesel. For that, it was used a questionnaire closed questions, organized in the likart scale, directed to the tree spheres of the research analysis, the biodiesel and its social, ambient and economic nuances, totaling 31 questionnaires full answered. In its objectives, the research was descriptive and in its approach it was qualitative. To the data analysis it was used statistical tools (Statistic software, 6.1 version and Microsoft Excel 2003). The research revealed the predominance of the ambient aspect in the sight of the teachers, followed by the social ones. The economic factors represent a minor percentage in the analysis when compared to other

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This thesis treats of a avaliation of a laboral gimnastics program of a electrical energy enterprise from Rio Grande do Norte. The leading aim of this work is to analyse the laboral gimnastics program with emphasis on functional performing and personal changes of staff of different categories. The work shows two divisions: at first, it was carried out the bibliographic study approaching the concepts and historic about the ergonomy and the main focus of study, the laboral gimnastics , performing factors and lifestyle.The second time , it was carried out the field study where was used a questionnaire to a 160 staff population which participate of laboral gymnastics program; then the data were analysed through three statistics analyses: multivaried__ clusters, qui-quadrado and multiple linear regression. The results aim to the confirmation that the laboral gymnastics program developed two years ago on enterprise proposes to the white-collar and operational workers an improving on their functional performing and also, to the changes in some aspects of lifestyle, like the food, leisure and stress level. In conclusion, it was checked that the investiment in life quality programs offer benefits both to the staff and the enterprise which will account with good services and satisfaction of customer. Therefore, it was concluded that the laboral gymnastics while a ergonomic tool and a physical activity, it is an investiment which needs more and more to be strengthened and inserted by many segments of society

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Performance measurement in highly competitive markets is a necessary measure for those who aim the top positions. The business performance measurement approach have reached relevant results in the literature, however, a different approach has recently appeared that broadened the perception of competition, where companies do not seek the competition among companies only, but also among supply chains. Brazilian Wind energy supply chain is living a structuring and expanding moment, with the major global players in the industry making investments in the country. This research aims to answer which are the key performance indicators that must be considered by the Brazilian wind energy sector companies, which are part in a broad perspective of supply chain competition. The research was executed in two steps: exploratory (literature review and a field research in the companies) and later a survey was conducted with the Brazilian Wind energy companies workers with the purpose to validate the performance indicators found in the exploratory step. The survey evaluated 40 performance indicators distributed among five major activities: Project prospection, building/execution, operation and maintenance, logistics and transverse processes, which summarize the performance of the entire supply chain, pointing the sinergy and the competitive level of the supply chain. The selected performance indicators reflect the high relevance of the costs dimension in the Brazilian energy companies performance, acting as a key performance indicator, is also indicates the limited performance management integration throughout the Brazilian wind energy supply chain

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The natural gas perform a essential paper, not only in primary sectors of energy, but also in others sectors of economy. The use natural gas will have expansion in Brazil, motivated by governmental decision to increase the participation of this fuel in the Brazilian energy matrix from 4% to 12% up until 2010. in order to reach the objective related to increase the consumption of natural gas in the energy matrix and to propose solutions to attend the electric requirements of heart and refrigeration, using natural gas as primary power plant. This thesis has a main objective to analysis the perception of businessmen of hotel sector about the feasability of investment with micro-cogeneration system by natural gas in their hotel in turistic sector, in Natal/RN. It s show a case for the hotels selected analyzing the actual knowledge of businessmen about alternative of new technology in generation of owner energy. There was make a interview using a standard form researching information about this topic. In this interview has shown 4 (four) canaries for businessmen with different configurations of investment in micro-cogeneration. Two of this canaries uses the project finance like option to make fasible this projects. The resulteis showed who businessmen has insecurity to make decision to put in office alone, or with a local company, and perhaps with a national company to perform for a alternative energy system, justifying, the alone feasability and without information by local businessmen. Apart from that, they are receptive for a option to put in office in micro-cogeneration configured in the settings using project finance