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    The comparison of levitation and lateral force of bulk and cut-pasted bulk GdBCO samples at different temperatures
    (Elsevier Science Sa, 2020) Guner, Sait Baris; Abdioglu, Murat; Ozturk, Kemal; Celik, Sukru
    In this work, in the first time, we have investigated the levitation and lateral force properties of bulk and cut-pasted bulk GdBCO samples at different temperatures and different cooling heights (CH) to determine the effect of cut-pasted process on the magnetic levitation force behaviour. The measurements of superconducting characteristics indicated that the attractive and repulsive force values of cut-pasted GdBCO sample are slightly lesser than those of GdBCO bulk sample. The maximum repulsive and attractive force values obtained as 15.45 N and -4.56 N for GdBCO bulk and as 14.78 N and -3.92 N for cut-pasted GdBCO samples at 37 K. Although there are many fabrication methods as melt-textured growth (MTG), top seeded infiltration growth (TSIG) and TSMG to produce large HTS samples, the desired large sample size and the sample shape compatible with the superconducting magnetic bearing systems are not still sufficient for the technological applications. In this study, the performed cut-pasted process and obtained magnetic levitation force data can be using for the increment sample size and the desired sample shape in the needed different geometry and size for superconducting magnetic bearing systems. (C) 2020 Elsevier B.V. All rights reserved.
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    Enhancing magnetic levitation and guidance force and weight efficiency of high-temperature superconducting maglev systems by using sliced bulk YBCO
    (Wiley, 2023) Abdioglu, Murat; Ozturk, U. Kemal; Guner, Sait Baris; Ozturk, Mehmet; Mollahasanoglu, Hakki; Yanmaz, Ekrem
    We aimed to enhance the magnetic force efficiency of Maglev systems without increasing total weight. For this aim, we divided YBCO bulks into three slices horizontally to utilize the YBCO-permanent magnetic guideway (PMG) interaction surface as much as possible. We used whole YBCO above PMGs with different magnetic pole directions (PMG-A and PMG-B) in two lying positions of transversal and longitudinal and investigated levitation and guidance force performances. It is determined that levitation and guidance forces by using YBCO in transversal lying mode are bigger compared to the longitudinal mode. For sliced YBCO, the maximum levitation force increased by 69% and 78%, while the guidance force enhancements are determined as 212% and 91%, compared to the whole YBCO above PMG-A and PMG-B, respectively. The levitation and guidance force density with respect to the total mass of unit a set of slices YBCO increased by 92% and 106%, respectively, compared to the whole YBCO above PMG-B in transversal mode. Since the higher levitation force and the lower total weight of the onboard unit are important parameters in point of the energy efficiency in Maglev and other levitation applications, the result of this study supplies useful data for the engineers and industrial partners.
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    Magnetic levitation force and trapped field properties of multiseeded YBCO with triangular arrangement of seeds
    (Wiley, 2022) Abdioglu, Murat; Guner, Sait Baris; Ozturk, Kemal; Yang, Chiaming; Chen, Ingann; Celik, Sukru
    Although there are studies in literature using different number of seeds with different arrangements, especially line and rectangular, it is seen that there is no detailed study handling the levitation force together with trapped field properties of triangular arrangement of seed in YBCO. Therefore, to further investigate the magnetic properties of seeded YBCO superconductors, we have fabricated cylindrical YBCO (YBa2Cu3O7) superconductors with triangular arrangement of the seeds with different seed distances. Maximum levitation force values were obtained as 39.4 N and 57.1 N, while the maximum guidance force values were obtained as -4.6 N, and -8.7 N, respectively, with single-seeded and triangular-seeded samples with seed distance of 14 mm. It was determined that the trapped field, levitation force, and guidance force firstly decreased from the single-seeded sample to the triangular-seeded sample with small seed distance and then increased with increasing seed distance. Increased field trapping and levitation force performances in the triangular-seeded samples with suitable seed distance indicate that the triangular arrangement of seeds is an eligible method to produce larger dimension YBCO samples with bigger shielding current radius and bigger averaged trapped field values.
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    Superconducting and levitation force characterisation of pyrene added MgB2 bulk superconductors
    (Elsevier Sci Ltd, 2020) Erdem, Ozge; Guner, Sait Baris; Celik, Sukru; Kucukomeroglu, Tayfur
    This research presents the influence of pyrene (C16H10) addition (0, 2, 4, 6, 8, 10 wt%) on the superconducting properties of bulk MgB2. For C16H10 added MgB2 samples, a shrinkage in a-lattice parameters was determined, whereas c-lattice parameters remained practically unchanged. The (110) peak observed at 2 theta approximate to 59.9 degrees slightly shifted to higher angles, the lattice strain increased and the crystallite size reduced after C16H10 addition. By virtue of induced stronger pinning force, the in-field critical current density (J(c)) increased after C16H10 addition. The J(c) value at 20 K and 4 T was obtained about two times higher (8.54 x 10(3) A/cm(2)) for 4 wt% C16H10 added MgB2 sample than that of the pure one. In addition, the variation of levitation force characteristic of MgB2 with increasing C16H10 content was determined at 20, 25 and 30 K. The best vertical levitation force performance in zero-field-cooled regime was obtained as 7.09 N/g at 20 K for 4 wt% C16H10 added MgB2 sample with 13 mm in diameter.