Electric Section
Mostrando 13-24 de 34 artigos, teses e dissertações.
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13. Avaliação de betas por fundamentos: uma análise de empresas do setor elétrico na América Latina / Estimating betas from fundamentals: an analysis of Latin American electric sector companies
It is necessary to calculate the cost of equity which effectively shows the intrinsic business risk. The most used method to estimate the cost of equity encompasses the use of average of traded stocks betas. Although, the number of electrical power companies with different activities: generation, distribution, transmission and trading, and the percentage tha
Publicado em: 2008
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14. A PolÃtica de atraÃÃo de investimentos industriais no Cearà e o impacto no emprego: Uma anÃlise do perÃodo 2002 - 2005 / The policy to attract industrial investments of CearÃ, and the impact on jobs: an analysis of period 2002 - 2005
This study aims to empirically assess the effectiveness of the Fund for Industrial Development (FDI) in the generation of employment, including the period from 2002 to 2005. Through the database of information from companies that received tax incentives to install, upgrade or relocate their investments in the State, were estimated two models: the first uses
Publicado em: 2008
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15. Migrações ascendentes de peixes neotropicais e hidrelétricas: proteção a jusante de turbinas e vertedouros e sistemas de transposição. / Upstream migrations of neotropical fishes and hidroelectric dams: protection downstream from turbines and from spillways and fish passages.
This work aims to examine engineering, mainly hydraulic engineering, aspects related to the effects of hydroelectric dams on upstream fish migration, identifying possible measures for the reduction of fish mortality, inside turbines draft tubes and in the region downstream from spillways, and describing the most common upstream fish passages, mainly vertical
Publicado em: 2008
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16. USO DE GERADORES EÓLICOS DE PEQUENO PORTE PARA IRRIGAÇÃO NO SEMI-ÁRIDO DO ESTADO DE SERGIPE. / USE OF WIND GENERATORS SMALL FOR IRRIGATION IN SEMI-ARID STATE SERGIPE.
The renewable sources of energies are shown as an interesting alternative to minimize the problem of the electric power lack faced by the rural man, mainly in the remote places where the difficulties of distribution of the electrification lines, above all in the economical aspect, they are big being shown unviable. The energy eolic besides other purposes, ca
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/04/2007
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17. Fotoionização de atomos relativisticos / Photoionization of relativistic atoms
In this work we present photoionization results for the valence s-electrons of Sodium, Potassium, Rubidium and Cesium atoms including relativistic effects. In our calculations we consider the photoionization of a non-polarized atom by linearly polarized light, using half occupation transition states, within the electric dipole approximation and the Local Den
Publicado em: 2007
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18. CONTRIBUTIONS TO STUDY OF WIND FARM CONNECTION TO THE UTILITY / CONTRIBUIÇÕES AO ESTUDO DE CONEXÃO DE GERAÇÃO EÓLICA À REDE ELÉTRICA
Distribution systems have not been designed to receive distributed generation (DG) units. The electric energy injection in these systems is safe and reliable if the characteristics regarding of DG interconnection in distribution power systems are considered: (i) Protection; (ii) Stability; (iii) Electric energy market; (iv) Quality of energy. In this work, a
Publicado em: 2007
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19. Silicon nano-oxidation using AFM tips. / Nano-oxidação do silício utilizando sonda de AFM.
Local anodic oxidation of silicon using Atomic Force Microscopy (AFM) was investigated by applying a negative voltage between silicon nitride tip and Si surfaces. All samples were cleaned with an ammonium-based solution known in literature as standard cleaning 1 (SC1) or a dip in a diluted hydrofluoric acid solution followed by SC1 or, also, boiling in isopr
Publicado em: 2007
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20. Effects of the geometrie, of the axial force and of the rotation in the friction welding repair / Efeitos da geometria, da força axial e da rotação no reparo por atrito
Interventions made in the oil industry for repairs in structures and mechanical components, represents nowadays high financial costs. It is even worse since the operations are made in explosion risk areas. The electric arc welding is one of the most common techniques in this kind of repair. However, this technique has many inconveniences, some of them are: h
Publicado em: 2007
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21. Níveis de salinidade e manejo da fertirrigação sobre o cultivo do tomateiro (Lycopersicon esculentum Mill) em ambiente protegido / Salinity control and fertigation management on the cultivation of tomato (Lycopersicon esculentum Mill) in greenhouse
Due to the need of increasing the productivity in the agricultural section the use of fertilizers in the production of food was increased, causing among other things the salinization of the soil, the consequences for the humankinds health and the environmental impact that are not totally known. This work had as objective evaluate the effect of different leve
Publicado em: 2007
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22. Evaluation of the hydraulic potential in hydrographic basins by using the geographical information systems / Avaliação do potencial hidráulico em bacias hidrográficas por meio de Sistemas de Informações Geográficas
The hydroelectric resources in the Country, either in terms of the capacity already installed and its potential still unexplored rather represent greatly strategic and economically important assets. In generation of the decentralized electric power, the hydroelectric minicentrals (MCHs) are distinguished within an environmental management and preservation co
Publicado em: 2007
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23. Hydrostatic pressure and electric-field effects on the shallow donor impurity states in GaAs-Ga0.7Al0.3As quantum-well wires
Using a variational procedure within the effective-mass approximation, we have made a theoretical study of the effects of hydrostatic pressure and applied electric fields on the binding energy of a shallow-donor impurity in square-transversal section GaAs-Ga0.7Al0.3As quantum-well wires. The electric field is applied in a plane of the transversal section of
Brazilian Journal of Physics. Publicado em: 2006-09
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24. Estudo da obtenção de imagens de tomografia de impedância elétrica do pulmão pelo método de otimização topológica. / Study of electrical impedance tomography image reconstruction of lungs by topology optimization method.
The Electrical Impedance Tomography (EIT) is a recent monitoring technique on biological tissues. The EIT allows us to obtain images representing a transversal plane of any section of human body (head, thorax, thigh, etc). Each image pixel is related to its corresponding value of electrical impedance (or resistivity). The images are generated from voltage va
Publicado em: 2006