Alcione Roberto Jurelo

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Superconducting fault current limiters (SCFCLs) represent a promising solution to the problem of increasing short- circuit currents in the grid. The SCFCL is based on the fast transition from the superconducting state to the normal state, causing a sudden increase in the impedance of the network. In this paper, we simulate the behavior of resistive-type(More)
We have experimentally studied the electrical conductivity near the normal-superconducting transition of two Y<sub>0.25</sub>Gd<sub>0.25</sub>Er<sub>0.25</sub>Nd<sub>0.25</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-&#x03B4;</sub> polycrystalline samples with different oxygen contents. The oxygen content for one of the samples is close to the optimum. The(More)
Since the discovery of the high Tc superconductors, many researches have been carried out on the different properties of these materials, especially on the transition temperature into the superconducting state. The rutheno-cuprates belong to a new class of composites, which were synthesized for the first time by Bauernfeind in 1995. Bernhard and(More)
We studied the effect of superconducting fluctuations on the electrical conductivity of granular samples of Y1−xPrxBa2Cu3O7−δ superconductors, with x =0.01, 0.03, 0.05, 0.07 and 0.10. Samples were prepared by the standard solid-state reaction technique, with two different types of calcination process, in air at 900 ̊ C ( x ≤ 0.07 ) and in vacuum at 850 ̊ C(More)
Since the discovery of the high Tc superconductors, many researches have been carried out on the different properties of these materials, especially on the transition temperature into the superconducting state. The rutheno-cuprates belong to a new class of composites, which were synthesized for the first time by Bauernfeind in 1995. Bernhard and(More)
The mechanical properties of REBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-&#x03B4;</sub> super conductor samples produced by different processing routes are compared, where RE corresponds to a natural mixture of rare-earth (RE) elements extracted from xenotime mineral. Xeno time can be used as a precursor for RE oxides that are used to produce electrotechnical(More)
Systematic conductivity measurements near TC in granular Ag-doped YBa2Cu3O7−δ superconductors are presented. Silver doped YBa2Cu3O7−δ samples were produced by different routes and characterized by X-ray diffraction, dc magnetization and electrical resistivity. The results were analyzed in terms of the temperature derivative of the resistivity and of the(More)
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