High Energy Research Organization (KEK) has engaged in development of the beam separation dipole, MBXF, toward the HL-LHC project. The magnet has a full length of 7 m and generates a magnetic field ...of 5.6 T in the magnet center at nominal operating condition of 12 kA and 1.9 K. Optimization of the magnetic model is performed through two and three dimensional studies and iterated until resultant field quality is within required tolerance. Field quality of the first full-scale prototype of MBXF (a.k.a. MBXFP1) is measured first at room temperature on the premises of the manufacturer, Hitachi Ltd. This result is used for comparison with the numerical models and the first validation of our design methodology. After then a further model tuning is considered for the magnetic design of the first series. The final validation of our design methodology is performed after the cold test of MBXFP1 in the vertical cryostat in KEK facilities. Finally we determine a magnetic design of the first series production with an expected sextupole integral and decapole integral, which are major systematic contributions to the field quality of MBXF, estimated to be <inline-formula><tex-math notation="LaTeX">0.0 \pm 1.6</tex-math></inline-formula> units and <inline-formula><tex-math notation="LaTeX">1.1 \pm 0.2</tex-math></inline-formula> units, respectively.
High Energy Accelerator Research Organization (KEK) is developing Nb-Ti based beam separation dipole (MBXF) for the high-luminosity Large Hadron Collider (HL-LHC) upgrade within the framework of ...CERN-KEK collaboration. This magnet produces field integral of 35 T*m in a 150 mm bore at 12 kA and 1.9 K. KEK has fabricated and tested three 2 m-long model magnets as in-house activities. After the technologies cultivated in these model magnet development was transferred from KEK to a manufacture, construction of the first full-scale prototype (MBXFP1) started in Hitachi. This paper reports test result of cold test for MBXFP1 including training, mechanical behavior, magnetic field quality and quench protection.
High luminosity upgrade of the Large Hadron Collider (HL-LHC) project has been launched to attain a ten times higher integrated luminosity than the current LHC that has been in operation for over ten ...years. For this goal, the quadruple and dipole magnets around two interaction points, the ATLAS and the CMS, will be upgraded. High Energy Accelerator Research Organization (KEK) is in charge of developing the new superconducting beam separation dipole magnet (D1). The main dipole field of 5.6 T in a large aperture of 150 mm is generated using a cos-theta coil wound with Nb-Ti cables at nominal operating current of 12.0 kA at 1.9 K corresponding to 75% of the load line ratio. The main challenges for the D1 are larger aperture, a high level of iron saturation, radiation resistance, and tight constraints on field quality. This article summarizes the results of a detailed analysis on field error. Electromagnetic simulation with ROXIE was carried out for the 2-D model of the new D1. As possible design changes, a diameter and position of heat exchanger holes in the iron yoke, and shape of the cryostat were considered. To reveal the influence on systematic error, packing factor of iron yoke, relative permeability of the stainless steel collar, and coil deformation during yoking were reflected to the baseline design. In addition, random geometric error was also estimated. Based on these results, contribution of each factor to field quality is studied.
Background and Objective
Periodontitis is the most common inflammatory disease caused by oral biofilm infection. For efficient periodontal treatment, it is important to enhance the outcome of ...existing regenerative therapies. The physical action of an ultrasound may be able to deliver a therapeutic gene or drugs into the local area of the periodontium being treated for periodontal regeneration. Previously, we developed “Bubble liposomes” as a useful carrier for gene or drug delivery, and reported that delivery efficiency was increased with high‐frequency ultrasound in vitro and in vivo. Hence, the aim of the present study was to examine the possibility of delivering genes into gingival tissues using Bubble liposomes and ultrasound.
Material and Methods
We attempted to deliver naked plasmid DNA encoding luciferase or enhanced green fluorescent protein (EGFP) into the lower labial gingiva of Wistar rats using Bubble liposomes, with or without ultrasound exposure. Ultrasound parameters were optimized for intensity (0‐4.0 W/cm2) and exposure time (0–120 s) to establish the most efficient conditions for exposure. The efficacy and duration of gene expression in the gingiva were investigated using a luciferase assay and fluorescence microscopy.
Results
The strongest relative luciferase activity was observed when rats were treated under the following ultrasound conditions: 2.0 W/cm2 intensity and 30 s of exposure time. Relative luciferase activity, 1 d after gene delivery, was significantly higher in gingiva treated using Bubble liposomes and ultrasound than in gingiva of the other treatment groups. Histological analysis also showed that distinct EGFP‐expressing cells were observed in transfected gingiva when rats were treated under optimized conditions.
Conclusion
From these results, the combination of Bubble liposomes and ultrasound provides an efficient technique for delivering plasmid DNA into the gingiva. This technique can be applied for the delivery of a variety of therapeutic molecules into target tissue, and may serve as a useful treatment strategy for periodontitis.
Telomeres are the repeated sequences at the chromosome ends which undergo shortening with cell division. The telomere shortening of the peripheral leukocytes is also facilitated by enhanced oxidative ...stress in various kinds of disease including ischemic heart disease, diabetes mellitus, apoplexy, and Alzheimer's disease. Telomere shortening in Parkinson's disease (PD) has not yet been reported. The pathogenesis for PD is also regarded to be associated with oxidative stress. We investigated 28 Japanese male PD patients ages 47–69. Although we could not find a statistical difference in the mean telomere length of peripheral leukocytes between the PD patients and the control participants, we found the mean telomere lengths to be shorter than 5 kb in only the PD patients and a significant PD-associated decrease in the telomeres with a length ranging from 23.1 to 9.4 kb in the patients in their 50s and 60s. These observations suggest that telomere shortening is accelerated in PD patients in comparison to the normal population.
•Optimization of the quench protection for our HTS-based model magnet of the rotating gantry.•Dependence of the protection scheme on temperature/current is estimated on the simulation base.•Maximum ...elapsed time after the magnet quench is independent from the operation temperature.•Protection resistor and detection voltage must be <4 Ω and <50 mV, respectively, at I = 300 A.
We studied quench protection criteria for high transition-temperature superconducting (HTS) model magnet that was fabricated to demonstrate the possibility of HTS-based gantry. We aim to evaluate the frequency of “flux jump” events of this model magnet with varying operating temperature (TOP), which was observed during previous excitation tests. Therefore, we investigated the operation margin for various TOPs based on simulation and developed the quench protection system of this model magnet. A short sample of rare-earth barium copper oxide coated conductor, which was used for winding the HTS coil, was prepared and its current-voltage characteristics were measured between the temperature range of 40–83 K. The obtained results were then implemented to our stand-alone simulation to perform the quench study. The maximum allowed elapsed time after the magnet quench was investigated for different operating currents and TOPs by varying the detection voltages (Vdets). Then, a protection circuit was integrated into our simulation to optimize the size of dump resistor (Rdump) and Vdet. Finally, it was observed that Rdump must not be above 4 Ω and Vdet must be kept below 50 mV to protect the HTS model magnet.
We have compared the mechanical properties and the degradation of the critical current after uniaxial tensile loading at room temperature (RT) and at 77 K of ex situ and in situ MgB 2 wires. The ...strain that the wires can withstand without degradation is at 77 K substantially higher than at RT. In order to explain the mechanical behavior of the wires, the lattice distortions of the different wire constituents and their texture have been measured simultaneously with the composite wire stress and strain in a high-energy synchrotron beamline. The different MgB 2 microstructure in both wire types is revealed in filament cross sections prepared by the focused-ion-beam technique and in fracture surfaces.
In this study, the fatigue behavior of Ti-15-3 alloy thin plate specimens with two different microstructures was determined. Two kinds of specimens were prepared with different heat treatments: ...solution treatment (S) and solution treatment followed by aging (S+A). The effects of the microstructures on the fatigue properties and fatigue crack growth behavior were significant in both specimens. The fatigue crack in both specimens propagated in transgranular mode. In the specimen S+A, crack propagation has occurred on non-crystallographic and was closely connected with the configuration of the α-phase platelet, which was caused by the heat treatment. The damage was characterized by dislocation debris clustering ahead of the crack tip.
A large aperture beam separation dipole (D1 magnet) is required to generate a field integral of 35 Tm at 12 kA and 1.9 K for the high luminosity upgrade of the large hadron collider (HL-LHC). ...High-energy accelerator Research Organization (KEK) fabricated the first 2 m model (MBXFS1) and a magnet test was performed in 2015-2016. Although the quench current reached the nominal operating current, training performance was not satisfactory. The measured azimuthal coil pre-stress was completely released below the nominal current, and this was suggested to be the main reason for the insufficient training performance. After the magnet test, MBXFS1 was disassembled and reassembled as MBXFS1b after increasing the coil pre-stress. In this paper, we report the reassembly of the magnet and test results focusing on the training performance.
The electromechanical properties of different cuprate high-temperature superconductors, notably two ReBCO tapes, a reinforced and a nonreinforced Bi-2223 tape, and a Bi-2212 wire, have been studied. ...The axial tensile stress and strain, as well as the transverse compressive stress limits at which an irreversible critical current degradation occurs, are compared. The experimental setup has been integrated in a high-energy synchrotron beamline, and the self-field critical current and lattice parameter changes as a function of tensile stress and strain of a reinforced Bi-2223 tape have been measured simultaneously. Initially, the Bi-2223 filaments exhibit nearly linear elastic behavior up to the strain at which an irreversible degradation is observed. At 77 K, an axial Bi-2223 filament precompression of 0.09% in the composite tape and a Bi-2223 Poisson ratio ν = 0.21 have been determined.
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