Superconducting neutron transmission imaging for investigating a sequential change in phase separations of low-melting Wood’s metalDang Vu, The; Shishido, Hiroaki; Aizawa, Kazuya; Oku, Takayuki; Oikawa, Kenichi; Harada, Masahide; Kojima, Kenji M.; Miyajima, Shigeyuki; Soyama, Kazuhiko; Koyama, Tomio; Hidaka, Mutsuo; Suzuki, Soh Y.; Tanaka, Manobu M.; Machida, Masahiko; Kawamata, Shuichi; Ishida, Takekazu
doi: 10.1088/1742-6596/2545/1/012019pmid: N/A
We built a new cryostat system for a current-biased kinetic inductance detector (CB-KID) to be able to place a sample at room temperature for conducting the neutron transmission imaging experiments with pulsed neutrons. A Wood’s metal alloy sample (Bi 50wt.%, Pb 25wt.%, Sn 12.5wt.%, Cd 12.5wt.%) of melting temperature 75.2°C was used to check a practical test by observing fine microstructures under beam power of 812 kW at beamline BL10 of J-PARC (MLF). The Wood’s metal is composed of four phases, of which one is a Cd-rich needle-like phase of an average width of 25 µm and length of 5 mm. Since Cd is a strong neutron absorber, it is suitable for observing the fine mosaic structure contrastingly in neutron transmission imaging. After neutron-transmission imaging with the Wood’s metal in the initial state, we subsequently melted the Wood’s metal sample and solidified it again by slow cooling during the same beam time. We were successful in observing an impressive change in morphology of the phases by neutron-transmission imaging. Room-temperature sample imaging is very convenient for possible users, and is expected to be very useful for applying our CB-KID system to versatile different materials of interests.
Demonstration and thermal equilibrium analysis of a 10 kJ capacity energy storage coil made of MgB2 with liquid hydrogen indirect coolingInomata, R; Onji, T; Yagai, T; Makida, Y; Shintomi, T; Komagome, T; Hirano, N; Hamajima, T
doi: 10.1088/1742-6596/2545/1/012025pmid: N/A
We have demonstrated an advanced superconducting power conditioning system, in which a superconducting magnetic energy storage (SMES) device, a generator based on a fuel cell (FC), and an electrolyzer are used to compensate for electricity fluctuations over a wide frequency range, combined with a liquid hydrogen storage system to both cool the SMES and provide pure hydrogen gas to the FC and other gas-dependent systems. To manufacture the coils for the SMES, we used MgB2, whose critical temperature is below the boiling temperature of hydrogen. We developed a 10 kJ SMES coil system indirectly cooled by liquid hydrogen using thermosyphon passive heat exchange to isolate the flammable hydrogen from the electrical components. We performed a successful demonstration of this system for both DC and AC currents ramped at different rates. In the present study, we use computer simulations involving heat balance equations to evaluate the stability of the system. The results obtained are expected to lead to the design of future large-capacity energy storage systems, such as the MJ class, which offer comparable performance to conventional NbTi SMES devices.
Peer Review Statementdoi: 10.1088/1742-6596/2545/1/011002pmid: N/A
All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.1. Type of peer review: Single anonymous2. Conference submission management system: Morressier3. Number of submissions received: 344. Number of submissions sent for review: 345. Number of submissions accepted: 336. Acceptance Rate (Submissions Accepted / Submissions Received × 100): 97.1 %7. Average number of reviews per paper: 2.158. Total number of reviewers involved: 319. Contact person for queries:Name: Hirofumi YamasakiAffiliation: Secretariat of International Symposium on SuperconductivityEmail: [email protected]* means value has been edited
Turbulent Structure and Characterization of ‘11’-type Iron-based Superconductors by Magneto-optical ImagingRen, T; Sun, Y; Pyon, S; Tamegai, T
doi: 10.1088/1742-6596/2545/1/012006pmid: N/A
Magneto-optical imaging is employed to investigate the vortex penetration modes in ‘11’-type iron-based superconductors (IBSs) Fe(Te0.6Se0.4) and FeSe single crystals. In Fe(Te0.6Se0.4), vortices penetrate mostly homogeneously from all edges, forming an unstable turbulent interface with pre-existing anti-vortices, where ‘Meissner hole’ emerges as those have been reported in ‘122’-type IBSs. In FeSe, however, the penetration is restricted to numerous mesoscopic stripe-like regions. Further experiments revealed an inhomogeneous vortex propagation pattern, where vortices are most likely to be channeled along the twin boundaries.
Removal of SUS304 fine particles transformed into martensite by the high gradient magnetic separation under dry conditionChen, H; Yang, Y; Miura, O
doi: 10.1088/1742-6596/2545/1/012031pmid: N/A
The interfusion of impurities such as metallic wear debris has been a major issue in the manufacturing process of foods, medicines and industrial products. Such debris originates with wearing of stainless-steel pipe joints or mechanical moving parts. Since the debris shows ferromagnetic properties by undergoing the strain-induced martensitic transformation of non-magnetic SUS304 (X5CrNi18-10), the magnetic separation system is much efficient to remove such debris from raw materials. In order to study the magnetic separation properties for the martensitic transformation fine particles, the several kinds of magnetic powder with different magnetization were prepared by controlling the amount of martensitic transformation by heat-treating SUS304 powders. The magnetic separation performance was evaluated by the high gradient magnetic separation (HGMS) experiments using the multilayer unidirectional magnetic wire filter under dry condition. The experimental results and FEM particle trajectory simulations revealed that the SUS304 powders transformed into martensite were removed at high speed of 0.1 m/s by the superconducting HGMS in a relatively low magnetic field.
Performance evaluation of superconductive-assisted machining (SUAM) with superconducting tape and two permanent magnetsIwasaki, S; Ishii, H; Kinoshita, Y; Otabe, E S; Matsuo, K; Nakasaki, T; Suzuki, K
doi: 10.1088/1742-6596/2545/1/012012pmid: N/A
In this study, the repulsive force causing magnetic levitation for superconductive-assisted machining (SUAM) is calculated using the finite element method. Although bulk superconductors have been used for SUAM, here, we propose a magnetic levitation tool that uses superconducting tape. To obtain a stronger repulsive force, various models of a SUAM are designed and calculated. The results show that a strong repulsive force can be obtained by using two permanent magnets. In addition, even if the superconducting tape is rotated during stacking due to stacking errors, the repulsive force is not affected, indicating that there is no need to optimize the stacking method. Therefore, we expect that increasing the number of layers will generate a repulsive force that is greater than that obtained with bulk superconductors.
Two-dimensional Superconductivity in Misfit Layered Compound (BiSe)1.10NbSe2Matsuzawa, S; Kitano, H; Pyon, S; Tamegai, T
doi: 10.1088/1742-6596/2545/1/012002pmid: N/A
Novel two-dimensional superconductivity in a misfit layered compound (BiSe)1.10NbSe2 with a critical temperature Tc of 2.7 K is reported. The temperature dependence of Hc2 is linear close to Tc for both H ∥ c-axis and H ∥ ab-plane, suggesting that the superconductivity is three-dimensional with some anisotropy. However, the angular dependence of Hc2 clearly reveals a cusp-like behavior, which can be explained by Tinkham model, indicating that the system is two-dimensional. In order to clarify the relationship between stripe structures on the surface and the two-dimensional superconductivity, we also performed the same measurement on a uniform microbridge sample. We found similar two-dimensional behavior even in a microbridge without linear defects, indicating that the origin of two-dimensional superconductivity in (BiSe)1.10NbSe2 is not related to the stripe structure.
The in- and out-of-plane magnetisation of highly underdoped YBa2Cu3O6+x single crystalsKokanović, I; Cooper, J R
doi: 10.1088/1742-6596/2545/1/012004pmid: N/A
Previously we have shown how measurements of static magnetic susceptibility χc(T) of YBa2Cu3O6+x single crystals for magnetic fields applied along the c-axis, and χab(T) for fields in the ab-plane, can give useful information about their thermodynamic properties which are still being hotly debated. SQUID magnetometry above the superconducting (s/c) transition temperature Tc is used for larger crystals, while piezolever torque magnetometry gives χc(T)-χab(T) for tiny crystals. Here we present new data for more heavily under-doped crystals with hole concentrations per CuO2 plane, p =0.058 to 0.073. We again find that the T-dependent anisotropy well above Tc arises from the pseudogap and the g-factor anisotropy, while at lower T there are Gaussian s/c fluctuations with a strong cut-off. This is possibly a different region where neutron scattering studies give evidence for competition between incommensurate magnetic short-range order and superconductivity. We have studied crystals with three values of x, measuring χc(T) and χab(T) immediately after fixing x by quenching on to a copper block and again after allowing sufficient time at room temperature for the Cu-O chains to order. Thus, we report data for three pairs of underdoped (UD) crystals with Tc ranging from 13 to 36 K, namely UD13 and UD20, UD15 and UD30, UD23 and UD36. As found previously for polycrystalline samples, ordering the Cu-O chains increases Tc and substantially reduces the Curie term. These are isotropic, in contrast to the Pauli-like susceptibility from the CuO2 planes where there is g factor anisotropy, and this allows us to make a powerful novel analysis. At higher T, χc(T)- χab(T) varies as a + bT where the bT term arises from the pseudogap. At lower T, deviations from this behaviour are analysed in terms of 2D or 3D Gaussian s/c fluctuations to obtain in-plane coherence lengths and upper critical fields as T→0.
Fundamental Study of the Removal of Microplastic Fibers Using Swirling Flow and Magnetic FieldFujii, Satoshi; Akiyama, Yoko; Manabe, Yuichiro; Sato, Fuminobu
doi: 10.1088/1742-6596/2545/1/012032pmid: N/A
Microplastic fibers (MPFs) derived from laundry wastewater and fishing nets, etc. have been found in the environment around the world, raising concerns about their ecological impact. Particularly for laundry wastewater, some of the MPFs are not removed by sewage plants, and are discharged into the environment. We have studied the removal method of MPFs by magnetic separation in sewage plants, but there were some problems for practical applications such as the desorption of magnetite from MPFs and blockage of magnetic filters. To solve the problems, we proposed a novel magnetic separation system combining swirling flow and opposing magnets. In this study, we investigated whether MPFs can be concentrated by particle trajectory simulations and lab-scale experiments. The simulations and experiments showed similar trends that MPFs can be concentrated by the proposed magnetic separation system. The magnetic separation performance will be improved by using a higher magnetic field of opposed superconducting bulk magnets.