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Recently, the significant peak effect was observed in the CeO 2 doped Y-Ba-Cu-O (YBCO) bulk materials grown using the infiltration growth (IG) method. The peak effect was attributed to the compositional fluctuations in the matrix, (Y,Sm)BCO. However, it was found that the peak effect was strongly spatially dependent. The inductively coupled plasma mass spectrometry (ICP-MS) results show that the concentration of Sm ranges from 5.8 3 10 À2 to 7.0 3 10 À3 wt% within the bulk. Notably, the peak effect is only observed in specimens where the concentration of Sm is higher than 1.5 3 10 À2 wt%. The spatial distribution of Sm dissolved from the SmBCO seed is the result of the way in which the liquid (BaCuO 2 and CuO) flows during the melting process of the IG technique. To suppress the variation in the composition, nano-sized Sm 2 O 3 particles are added to the precursor powders in this study. Microstructural analysis demonstrates that with the addition of nano-sized Sm 2 O 3 , the concentration of Sm can be enhanced to be higher than 1.5 3 10 À2 wt% within the bulk. Therefore, the peak effect can be observed throughout the bulk material. Besides, more symmetrical trapped magnetic field profiles can be obtained. P. Paranthaman-contributing editor Manuscript No. 30973.

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Abstract:In designing a horizontal-axis wind turbine (HAWT) blade, system integration between the blade design and the performance test of the generator is important. This study shows the aerodynamic design of a HAWT blade operating with an axial-flux permanent magnet (AFPM) generator. An experimental platform was built to measure the performance curves of the AFPM generator for the purpose of designing the turbine blade. An in-house simulation code was developed based on the blade element momentum (BEM) theory and was used to lay out the geometric shape of the turbine blade, including the pitch angle and chord length at each section. This simulation code was combined with the two-dimensional (2D) airfoil data for predicting the aerodynamic performance of the designed blades. In addition, wind tunnel experiments were performed to verify the simulation results for the various operating conditions. By varying the rotational speeds at four wind speeds, the experimental and simulation results for the mechanical torques and OPEN ACCESSEnergies 2014, 7 7774 powers presented good agreement. The mechanical power of the system, which maximizes at the best operating region, provided significant information for designing the HAWT blade.