The Japan Proton Accelerator Research Complex (J-PARC) is a world-class accelerator facility for particle and nuclear physics experiments such as the rare kaon decays experiment (KOTO), the T2K ...long-baseline neutrino experiment, and future projects such as COMET. A new stretcher ring (SR) comprising a combined function superconducting magnet is proposed to run all of the facilities at the same time, which can improve beam efficiency and increase operating time. In order to achieve the field quality requirements on the magnet aperture, it is critical to identify an optimum pole shape. Dipole, quadrupole, and sextupole fields are required for the combined function magnet. To find the best design parameters for this analysis, we employed singular value decomposition. The singular value decomposition (SVD) technique resulted in a solution to the desired parameters and a quick process to obtain a 2D pole profile.
Ultra-thin A15 composite wires with a diameter of 0.03-0.05 mm are being developed by National Institute for Materials Science (NIMS) to realize flexible Rutherford cables for high field ...superconducting accelerator magnets. Since the bending strain is approximately proportional to the wire diameter, a cable composed of thin wires can be bent to a smaller bending diameter without the degradation of critical current ( I c ). Thus, react-and-wind cables with ultra-thin Nb 3 Sn wires are expected to be realized. In our previous study, the basic mechanical properties including fracture strength and Young's modulus of 0.05-mm-thick bronze-processed Nb 3 Sn wires were evaluated by a single- fiber tensile test. As a next step, in this study, a tensile test was conducted for a twisted cable with 19 0.05-mm-thick wires at room temperature to confirm whether the mechanical strength of the twisted cable can be predicted from that of the single wire. The stress tolerance of the single wire and twisted cable was assessed by measuring I c at 4.2 K after applying various uniaxial tensile loads at room temperature. The tensile stress limit of I c was compared between the single wire and twisted cable.
Flexible Rutherford cables are needed to realize high field superconducting magnets with A15 conductors based on the react-and-wind (R&W) technology. Aiming such an application, ultra-thin A15 ...composite wires with a diameter of 0.03-0.05 mm have been developed by the National Institute for Materials Science (NIMS). Mechanical properties of such ultra-thin Nb 3 Sn wires were evaluated to determine the cabling parameters and mechanical analysis of twisted cables. Tensile tests were performed at room temperature for 0.05 mm-thick Nb 3 Sn wires before and after heat treatment for the first time. Basic mechanical parameters such as 0.2% proof strength and fracture strength were evaluated from a stress-strain curve. Young's modulus of such a thin wire was determined from unlading and reloading slopes of a load-stroke curve for the specimens with different gauge lengths. Fracture strain was estimated without using extensometers and strain gauges by correcting for machine deformation. Based on these results, we concluded that a simple technique to measure stress-strain curves for ultra-thin Nb 3 Sn wires was able to be established.
Summary
Background
Cepharanthine (CEP), a compound extracted from the vine Stephania cephalantha, is commonly prescribed to treat alopecia areata; however, the scientific evidence for its efficacy is ...limited.
Aim
To investigate the effect of CEP and its structural analogues on human hair growth in vitro.
Methods
The effects of CEP and three of its structural analogues on the proliferation of human dermal papilla cells (hDPCs) and human outer root sheath cells (hORSCs) were investigated. Their effects on vascular endothelial growth factor (VEGF) expression were also assessed by real‐time PCR. Activation of pathways leading to VEGF expression, such as intracellular Ca2+ mobilization and hypoxia‐inducible factor (HIF) expression, was also characterized.
Results
CEP and two of its structural analogues significantly stimulated the growth of hDPCs but not hORSCs. Moreover, CEP and all three structural analogues significantly induced the expression of VEGF in hDPCs. CEP increased the intracellular Ca2+ concentration in hDPCs. CEP also increased the expression of HIF‐1α and HIF‐2α and induced the expression of HIF‐responsive genes in hDPCs, even under normoxia.
Conclusions
These results suggest that CEP and its structural analogues have the potential to restore hair growth by promoting the proliferation of hDPCs and increasing their expression of VEGF.
A varistor is a non-linear <inline-formula><tex-math notation="LaTeX">V</tex-math></inline-formula>-<inline-formula><tex-math notation="LaTeX">I</tex-math></inline-formula> resistor and its feature ...helps to extract stored energy of the magnet quickly while suppressing the magnet voltage. High Energy Accelerator Research Organization (KEK) decided to install the varistor for the test facility in order to conduct quench training of a superconducting magnet safely. The new energy extraction (EE) system consists of varistors made of silicon carbide (SiC) disks and is designed to extract energy up to 5 MJ. These varistors were installed prior to the test of the HL-LHC D1 magnet in 2023 and validated throughout the power test. A current imbalance and turn-on time (<inline-formula><tex-math notation="LaTeX">t_\text{ON}</tex-math></inline-formula>) among the varistor units, which could affect performance of the magnet protection, are monitored and measured to be within <inline-formula><tex-math notation="LaTeX">\pm \text{4}\%</tex-math></inline-formula> and 300 µs, respectively.
Nb 3 Sn superconducting wires are under consideration for producing high field accelerator magnets for the proposed Future Circular Collider (FCC) due to their high critical field. R&D studies are ...ongoing worldwide with a target non-Cu critical current density ( J c ) of 1500 A/mm 2 at 4.2 K, 16 T. As an accomplishment of this R&D, one of the conductor manufacturers, JASTEC, has developed Nb 3 Sn wires with non-Cu J c higher than 1100 A/mm 2 at 16 T, 4.2 K by a distributed-tin (DT) method. In high field Nb 3 Sn magnets, degradation of performance has been frequently reported due to the brittleness of Nb 3 Sn and the high electromagnetic force. To realize more robust Nb 3 Sn accelerator magnets, electro-mechanical properties of the conductors should be deeply understood. In this study, the variation of the critical current with mechanical loading is evaluated for a DT Nb 3 Sn wire in two configurations, i.e. under axial strain and under transverse compression.
New generation accelerators, such as future circular collider (FCC), require superconducting wires with non-copper J c of 1500 A/mm 2 at 16 T and 4.2 K. Kobe Steel Ltd. developed Nb 3 Sn conductors ...with elemental addition to achieve the target J c for FCC. The effect of zinc addition to the copper matrix on the superconducting properties and mechanical strength of the distributed tin (DT) method processed Nb 3 Sn wire is studied. In the present study, the I c -strain characteristics were evaluated using Walters springs (WASP) at 16 T and 4.2 K to investigate the impact of copper (Cu) and brass (Cu-Zn) matrix on further J c improvement and mechanical robustness.
We report the test results of the first series beam separation dipole, MBXF1, for the HL-LHC project. The magnet has a full length of 7 m and is designed to generate a field integral of 35 T ...<inline-formula><tex-math notation="LaTeX">\cdot</tex-math></inline-formula> m at a nominal operating current (<inline-formula><tex-math notation="LaTeX">I_\text{nominal}</tex-math></inline-formula>) of 12.11 kA. The cold test is performed at the test facility in High Energy Accelerator Research Organization (KEK) using a 9-m deep vertical cryostat. The test consists of two test cycles with one thermal cycle. In each of the test cycles MBXF1 is energized in superfluid helium at 1.9 K and subjected to a series of quench training and magnetic field evaluation. The test shows that the magnet has a good training performance as it reaches <inline-formula><tex-math notation="LaTeX">I_\text{nominal}</tex-math></inline-formula> with two quenches and an ultimate operating current (<inline-formula><tex-math notation="LaTeX">I_\text{ultimate}</tex-math></inline-formula>) of 13.231 kA with seven quenches. Furthermore we observe no quench during the training of the second test cycle, indicating MBXF1 has a good training memory. Magnetic measurements of MBXF1 show that the discrepancy between the measured and computed harmonics at the magnetic center is 3.9 units for normal sextupole and less than 0.5 units for the other allowed-normal multipoles. Finally sextupole integral (<inline-formula><tex-math notation="LaTeX">\bar{b}_{3}</tex-math></inline-formula>) and decapole integral (<inline-formula><tex-math notation="LaTeX">\bar{b}_{5}</tex-math></inline-formula>), which are major systematic field errors in MBXF, respectively are estimated to be 2.0 units and 1.7 units for an actual environmental condition with ferromagnetic materials in the LHC accelerator tunnel.
As a Japanese contribution to the High-Luminosity Large Hadron Collider (HL-LHC) upgrade, KEK is in charge of developing the beam separation dipole cold masses. The full-scale prototype magnet ...(MBXFP1) was constructed in Hitachi and powering test at cold was conducted at KEK. After the test, the magnet was returned to Hitachi for the final assembly of the cold mass. The pressure vessel design of the cold mass was carried out by KEK in accordance with ASME code. A new design of bus leads was proposed to satisfy the requirement of flexibility as well as mechanical support and electrical insulation. Welding of the extremity pipes was challenging due to tight position tolerance. This article reports the structure, pressure vessel design, and assembly of the LMBXF prototype cold mass (LMBXFP1) including bus work, instrumentation, and welding works with geometrical measurements.
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