Use of superconducting coils for wind turbines and electric aircraft is of interest because of the potential for high power density and weight reduction. Here we test a racetrack coil developed as a ...proof-of-concept for cryogen-free superconducting motors and generators. The coil was wound with 1209 m of 0.7-mm-diameter insulated tube-type Nb3Sn wire. The coil was epoxy-impregnated, instrumented, covered with numerous layers of aluminized mylar insulation, and inserted vertically into a dewar. The system was cooled to 4.2 K, and a few inches of liquid helium was allowed to collect at the bottom of the dewar but below the coil. The coil was cooled by conduction via copper cooling bars were attached to the coil but also were immersed in the liquid helium at their lower ends. Several current tests were performed on the coil, initially in voltage mode, and one run in current mode. The maximum coil Ic at 4.2 K was 480 A, generating 3.06 T at the surface of the coil. The coil met the design targets with a noticeable margin.
In this work we studied the influence of SnO2 doping on the critical fields and temperatures of MgB2 bulk samples. Bulk samples were made by mixing ex-situ MgB2 powder with 5 wt% SnO2 powder and then ...pressing the mixed powders into pellets using a pressure of 2000 psi. The bulk pellets were sintered at 900°C in a furnace under flowing Ar. The samples were quenched to room temperature after dwelling at 900°C for 5h. XRD, SEM, and magnetic measurements were made on doped and control samples. XRD showed a decomposition of the SnO2 and very slight reductions in the a-axis and c-axis lattice parameters of the MgB2 phase. M-T (Magnetization-Temperature) curves showed a decrease in Bc2 of approximately 1 T in the temperature range of 24 K - 39 K with SnO2 additions as compared to the control samples.
Abstract Objective To investigate real-world effectiveness of tumor necrosis factor inhibitors (TNFi) in patients with axial spondyloarthritis (axSpA) and the association with (i) treatment line ...(second and third TNFi-series) and (ii) reason for withdrawal from the preceding TNFi lack of efficacy (LOE) vs adverse events (AE). Methods Prospectively collected routine care data from 12 European registries were pooled. Rates for 12-month drug retention and 6-month remission Ankylosing Spondylitis Disease Activity Score C-reactive protein inactive disease (ASDAS-ID) were assessed in second and third TNFi-series and stratified by withdrawal reason. Results We included 8254 s and 2939 third TNFi-series; 12-month drug retention rates were similar (71%). Six-month ASDAS-ID rates were higher for the second (23%) than third TNFi (16%). Twelve-month drug retention rates for patients withdrawing from the preceding TNFi due to AE vs LOE were similar for the second (68% and 67%) and third TNFi (both 68%), while for the second TNFi, rates were lower in primary than secondary non-responders (LOE <26 vs ≥26 weeks) (58% vs 71%, P < 0.001). Six-month ASDAS-ID rates for the second TNFi were higher if the withdrawal reason was AE (27%) vs LOE (17%), P < 0.001, while similar for the third TNFi (19% vs 13%, P = 0.20). Conclusion A similar proportion of axSpA patients remained on a second and third TNFi after one year, but with low remission rates for the third TNFi. Remission rates on the second TNFi (but not the third) were higher if the withdrawal reason from the preceding TNFi was AE vs LOE.
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