Permanent Magnets
Mostrando 25-36 de 37 artigos, teses e dissertações.
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25. Generated voltage variation and permanent magnet magnetic condition analysis. / Análise da variação da tensão gerada e do estado de magnetização em um gerador com ímãs permanentes.
Aiming to analyze the performance of a permanent magnet generator, operating under variable load and quantifying the corresponding condition of its magnets, we have developed a prototype adaptable to wind generators. As one of the purposes of this work is to study the magnetic performance of the permanent magnets in several points of load, we have chosen fer
Publicado em: 2007
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26. Optimization of biplanar gradient coils for magnetic resonance imaging
"Open" magnetic resonance imaging (MRI) scanners are frequently based on electromagnets or permanent magnets, and require self-shielded planar gradient coils to prevent image artifacts resulting from eddy currents in metallic parts of the scanner. This work presents an optimization method for the development of self-shielded gradient coils with biplanar geom
Brazilian Journal of Physics. Publicado em: 2006-03
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27. "Estudo da influência do zircônio e gálio nas propriedades magnéticas e na microestrutura dos imãs permanentes à base de praseodímio" / STUDY OF THE INFLUENCE OF ZIRCONIUM AND GALLIUM ON THE MAGNETIC PROPERTIES AND MICROSTRUCTURES OF PRASEODYMIUM-BASED PERMANENT MAGNETS
Nesse trabalho estudou-se a influência da adição de 0,5 % at. de zircônio (Zr) e gálio (Ga) nos ímãs permanentes à base de praseodímio (Pr) HD sinterizados obtidos por uma mistura de ligas. As ligas utilizadas foram: Pr12,6Fe68,3Co11,6B6Zr0,5Ga1, Pr16Fe75,5B8Zr0,5 e Pr13Fe80,5B6Zr0,5. A investigação foi realizada a partir das medidas das proprieda
Publicado em: 2006
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28. Contribuições para melhoria do desempenho e viabilidade de fabricação de scanners indutivos / Contributions to improve the performance, and the manufacture viability of inductive scanners
Scanners are devices that deftects a light beam and converts a spot light in a well controlled amplitude and frequency scan line. Several applications uses the generated pattem to code or decode data, common examples ar,e barcode readers, and laser printers. A light beam can be deftected by different means. In this work, the scanner deftects the light by ref
Publicado em: 2006
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29. A study of Pr-Fe-B magnets produced by a low-cost powder method and the hydrogen decrepitation process
Sintered Pr-based magnets were produced using a new laboratory technique for powder handling. Unlike the conventional procedure for preparing sintered permanent magnets in the laboratory, the powder technique used in this investigation does not require a glove box. The effects of processing parameters on the magnetic properties of Pr-based sintered magnets p
Materials Research. Publicado em: 2005-06
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30. Single axis controlled attraction type magnetic bearing
This paper presents a new type of magnetic bearing with active control only in axial direction. The bearing uses two pairs of permanent magnets working in attraction mode to restrict the radial motion and a control system composed of two electromagnets, a gap sensor and a controller to keep the axis in a fixed axial position. The principle, the dynamic model
Journal of the Brazilian Society of Mechanical Sciences. Publicado em: 2002-11
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31. Mean field J C estimation for levitation device simulations in the bean model using permanent magnets and YBCO superconducting blocks
This work presents a mean field estimation of JC as a bulk characteristic of YBCO blocks. That average JC allows a good fitting of the finite-element-method (FEM) simulation of the levitation forces to experimental results. That agreement is quite enough for levitation requirements of device projects, at short gaps and zero field cooling process, within the
Brazilian Journal of Physics. Publicado em: 2002-09
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32. Analise eletromagnetica do motor de partida atraves da aplicação do metodo de elementos finitos
This work has the aim of making an electromagnetic analysis of the Starting Motor using a two-dimension Finite Element Method application. For computer calculation, a commercial magnetic analysis software called FLUX 2D is employed. The Starting Motor is a direct current motor with permanent magnets on the stator and its nominal power is 1.1 KW. The method e
Publicado em: 1997
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33. Investigações sobre o processo de deposição de filmes em plasmas de organometalico
Thin films were deposited by plasma polymerization from plasmas of mixtures of tetramethylsilane (TMS), He and Ar with oxygen and with nitrogen. Both the discharges and the films were studied. Three deposition systems were used. In the first, a direct current plasma was maintained between circular parallel-plate electrodes mounted in a Pyrex reactor. In the
Publicado em: 1995
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34. Quantitative Modeling and Optimization of Magnetic Tweezers
Magnetic tweezers are a powerful tool to manipulate single DNA or RNA molecules and to study nucleic acid-protein interactions in real time. Here, we have modeled the magnetic fields of permanent magnets in magnetic tweezers and computed the forces exerted on superparamagnetic beads from first principles. For simple, symmetric geometries the magnetic fields
The Biophysical Society.
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35. Characterisation of respiratory health and exposures at a sintered permanent magnet manufacturer.
Sintered permanent magnets are made from the powdered metals of cobalt, nickel, aluminium, and various rare earths. During production, exposure to respirable crystalline silica and asbestos may also occur. Reported here is a cross sectional study of 310 current and 52 retired hourly employees who worked 10 or more years making sintered magnets. Each particip
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36. Curvature Induced by Amyloplast Magnetophoresis in Protonemata of the Moss Ceratodon purpureus1
After gravistimulation of Ceratodon purpureus (Hedw.) Brid. protonemata in the dark, amyloplast sedimentation was followed by upward curvature in the wild-type (WT) and downward curvature in the wwr mutant (wrong way response). We used ponderomotive forces induced by high-gradient magnetic fields (HGMF) to simulate the effect of gravity and displace th
American Society of Plant Physiologists.