Percorrer por autor "Margato, Elmano"
A mostrar 1 - 8 de 8
Resultados por página
Opções de ordenação
- Comparing the Power Losses of Power Supplies for Fast-Field Cycling Nuclear Magnetic Resonance EquipmentPublication . Lima, Marco; Pereira, Bruno; Sousa, Duarte M.; Roque, António; Margato, ElmanoThe main feature of the Fast-Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) power supplies is to drive a controlled current fulfilling the requirements of this technique. This feature allows fast switching the current of the FFC magnet and performing accurate and repetitive current cycles. When designing this equipment the power losses is not a fundamental parameter of the optimization process but are estimated in order to validate the topology of the final solution giving that the efficiency of the power solution influences the power consumption, and therefore the operational costs, which should be minimized. Under this context, from the power efficiency viewpoint, the power losses of two possible solutions are compared and discussed in this paper. Typical FFC current cycles are used as reference in order to balance the pros and cons of both solutions.
- Comparing two Power Supplies for Fast-Field Cycling Nuclear Magnetic Resonance Relaxometers: Power Losses and PerformancePublication . Lima, Marco; Pereira, Bruno; Sousa, Duarte M.; Roque, António; Margato, Elmano
- Control of a Power Supply with Cycling Current Using Different ControllersPublication . Roque, António; Maia, José; Margato, Elmano; Sousa, Duarte M.; Marques, GilFast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometers require controlled current sources in order to get accurate flux density with respect to its magnet. The main elements of the proposed solution are a power semiconductor, a DC voltage source and the magnet. The power semiconductor is commanded in order to get a linear control of the flux density. To implement the flux density control, a Hall Effect sensor is used. Furthermore, the dynamic behavior of the current source is analyzed and compared when using a PI controller and a PD2I controller.
- FFC NMR Relaxometers on Education Topologies, control techniques and electromagnetic devicesPublication . Roque, António; Sousa, Duarte M.; Margato, Elmano; Marques, Gil; Sebastião, Pedro José
- Flux density distribution of a magnet with axial symmetry to be used in FFC-NMRPublication . Roque, António; Sousa, D. M.; Margato, Elmano; Machado, M.; Maia, José
- Magnetic Flux Density Distribution in the Air Gapof a Ferromagnetic Core With SuperconductingBlocks: Three-Dimensional Analysis andExperimental NMR ResultsPublication . Roque, António; Sousa, Duarte M.; Margato, Elmano; Machado, Vítor; Sebastião, Pedro; Marques, G.D.The design of magnetic cores can be carried out bytaking into account the optimization of different parameters inaccordance with the application requirements. Considering thespecifications of the fast field cycling nuclear magnetic resonance(FFC-NMR) technique, the magnetic flux density distribution,at the sample insertion volume, is one of the core parametersthat needs to be evaluated. Recently, it has been shown that theFFC-NMR magnets can be built on the basis of solenoid coilswith ferromagnetic cores. Since this type of apparatus requiresmagnets with high magnetic flux density uniformity, a new typeof magnet using a ferromagnetic core, copper coils, and supercon-ducting blocks was designed with improved magnetic flux densitydistribution. In this paper, the designing aspects of the magnetare described and discussed with emphasis on the improvement ofthe magnetic flux density homogeneity(ΔB/B0)in the air gap.The magnetic flux density distribution is analyzed based on 3-Dsimulations and NMR experimental results.
- Reversible Current Power Supply for Fast-Field Cycling Nuclear Magnetic Resonance EquipmentPublication . Lima, M.; Sousa, Duarte M.; Roque, António; Margato, Elmano
- Superconductivity and their applicationsPublication . Roque, António; Sousa, Duarte M.; Fernão Pires, Vítor; Margato, ElmanoThe research in the field of superconductivity has led to the synthesis of superconducting materials with features that allow you to expand the applicability of this kind of materials. Among the superconducting materials characteristics, the critical temperature of the superconductor is framing the range and type of industrial applications that can benefit from them. Some examples of industrial applications incorporating superconducting materials stand out in this paper. Among other possibilities, the nuclear magnetic resonance, the magnetic levitation train, the transport processing of electrical energy (motors, generators, transformers and power lines) and superconducting magnetic energy storage (SMES) systems are already solutions contributing to the nowadays daily life, but more than that, are solutions that will contribute to improve the quality of life of many human beings in the near future. In addition to these solutions, in this paper are presented and discussed the pros and cons of a solution designed for the fast field cycling nuclear magnetic resonance technique that benefits of the usage of superconducting blocks.