956 resultados para Densidade eletrônica


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Pós-graduação em Ensino de Física - FCT

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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A large number of metal alloys are used in Dentistry for the manufacture of fixed and removable dentures. In the oral cavity, these structures are exposed to a chemically aggressive medium, like saliva and mechanical efforts, like mastication. In addition, acidic solutions containing fluoride ions are also frequently used in dental treatments to prevent dental plates and decays development. In this context, it was considered important to investigate the influence that a fourth element could exert when added to the ternary alloy Ni-Cr-Mo, largely used in Brazil. Therefore, electrochemical tests were done to evaluate the resistance to corrosion of quaternary alloy 65Ni-25Cr-5Mo-5Ta and 65Ni-25Cr-5Mo-5W in NaF solution 0,08mol / L, pH = 4.7. For greater understanding the microstructure and morphology of alloys were studied, through metallographic analysis, using optics microscopy and electron microscopy scanning. For the electrochemical tests were applied techniques traditionally used in corrosion researches, such as: potential measures in open circuit (OCP) and cyclic polarization (CP). It was found that both quaternary alloys showed very similar results. Comparing these quaternary alloys with the ternary 65Ni-25Cr-10Mo, it was found that the quaternary alloys exhibit greater resistance to corrosion, in other words, less passivation current density than the ternary alloy, showing that it is advantageous to add a fourth element in the alloy

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This study aims to develop a computer program based on VBA programming language, using Microsoft Excel, for designing pumping systems of water. The program allows the user to determine the economical diameter, using the equation of Bresse, for a given installation, since the geometric elevation, the material of the tube, the accessories along the line and the volumetric flow are known. In addition, the program estimates the total annual cost of the installation for three different diameters, in order to compare which diameter is more advantageous from an economical perspective. The program interface is designed to be simple and intuitive with the intention of being didactic and offering to engineering students an advantageous tool to analyze this type of project. Microsoft Excel was chosen for this work because is present in virtually all personal computer, and is an indispensable tool for educational purposes

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In this work, we address the informational Density Index (IDI) a methodological Option How To be used on the Research Procedures Analysis of Commerce Geography. The IDI and an indicator of Technological Complexity level of economic activities and a review and made a database from CNEFE / NCEA, where the first signifies the National Register of Establishments for statistical purposes and the second means a National Classification Economic Activities. Elaborated with emphasis on discussion of between center and centrality relations, wish to present a constitution of a data base on level sampling with an analysis elaboration do IDI from the criteria: home-page and e - commerce. This methodology helps us understand how polycentric structures, locational enterprise well as a reflection on the middle cities using a through the analysis on city of São Carlos/SP. Where we see the establishments with greater and lesser content as well as its geographical distribution, noting of according to the criteria listed number of establishments with IDI 0 very relevant. Our analysis as well as such divisions that meet greater index, so, IDI 2 like to financial activities. Also present at methodological level the city of São José do Rio Preto/SP paragraph seizure of care when working there in database

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A large number of metal alloys are used in Dentistry for the manufacture of fixed and removable dentures. In the oral cavity, these structures are exposed to a chemically aggressive medium, like saliva and mechanical efforts, like mastication. In addition, acidic solutions containing fluoride ions are also frequently used in dental treatments to prevent dental plates and decays development. In this context, it was considered important to investigate the influence that a fourth element could exert when added to the ternary alloy Ni-Cr-Mo, largely used in Brazil. Therefore, electrochemical tests were done to evaluate the resistance to corrosion of quaternary alloy 65Ni-25Cr-5Mo-5Ta and 65Ni-25Cr-5Mo-5W in NaF solution 0,08mol / L, pH = 4.7. For greater understanding the microstructure and morphology of alloys were studied, through metallographic analysis, using optics microscopy and electron microscopy scanning. For the electrochemical tests were applied techniques traditionally used in corrosion researches, such as: potential measures in open circuit (OCP) and cyclic polarization (CP). It was found that both quaternary alloys showed very similar results. Comparing these quaternary alloys with the ternary 65Ni-25Cr-10Mo, it was found that the quaternary alloys exhibit greater resistance to corrosion, in other words, less passivation current density than the ternary alloy, showing that it is advantageous to add a fourth element in the alloy

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This study aims to develop a computer program based on VBA programming language, using Microsoft Excel, for designing pumping systems of water. The program allows the user to determine the economical diameter, using the equation of Bresse, for a given installation, since the geometric elevation, the material of the tube, the accessories along the line and the volumetric flow are known. In addition, the program estimates the total annual cost of the installation for three different diameters, in order to compare which diameter is more advantageous from an economical perspective. The program interface is designed to be simple and intuitive with the intention of being didactic and offering to engineering students an advantageous tool to analyze this type of project. Microsoft Excel was chosen for this work because is present in virtually all personal computer, and is an indispensable tool for educational purposes

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In this work, we address the informational Density Index (IDI) a methodological Option How To be used on the Research Procedures Analysis of Commerce Geography. The IDI and an indicator of Technological Complexity level of economic activities and a review and made a database from CNEFE / NCEA, where the first signifies the National Register of Establishments for statistical purposes and the second means a National Classification Economic Activities. Elaborated with emphasis on discussion of between center and centrality relations, wish to present a constitution of a data base on level sampling with an analysis elaboration do IDI from the criteria: home-page and e - commerce. This methodology helps us understand how polycentric structures, locational enterprise well as a reflection on the middle cities using a through the analysis on city of São Carlos/SP. Where we see the establishments with greater and lesser content as well as its geographical distribution, noting of according to the criteria listed number of establishments with IDI 0 very relevant. Our analysis as well as such divisions that meet greater index, so, IDI 2 like to financial activities. Also present at methodological level the city of São José do Rio Preto/SP paragraph seizure of care when working there in database