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The magnetic field source is the most expensive element of a magnetic refrigeration device. The design of an efficient magnet with high and low field regions, using reduced volumes of permanent magnets, is of paramount importance for the practical application of this new technology. A two-pole rotary magnet formed by sectors of oriented hard magnets and soft iron pieces is optimized in angular width and magnetization direction of each sector. A quadratic approximation is used for the optimization of the defining angles. This procedure provides the parameters that result in extreme values of a given functional F, defined as an efficiency variable of the working device. The procedure also gives the correlation between parameters and the relative importance of the deviations with respect to their mathematical optimal values. An optimized magnet has also been built, and the resulting calculated fields are compared with experimental measurements in the real system.

Graded anodes for anode-supported solid oxide fuel cells are fabricated by tape casting and subsequent cold lamination of plates using different compositions. Rheological parameters are adjusted to obtain stable suspensions for tape casting. The conditions for the tape casting and lamination will be described. Flexural strength of the reduced cermets measured using three-point bending configuration is 468 ± 37 MPa. The graded anode supports are characterized by scanning microscope observations, intruded mercury porosimetry, and resistivity measurements, showing an adequate and homogeneous distribution nickel, zirconia, and pores. The laminated samples showed a total porosity of 18.7 % (in vol%) and a bimodal pore size distribution centered in 20 and 150 nm, and the measured electrical resistivity of this sample was 120 ± 12 μΩ cm. The novelty of the present work is the lamination of tapes at room temperature without using plasticizers. This is made by the combination of two different binders with varying T (glass transition temperature) which resulted in plastic deformation at room temperature. Those results indicate that the