Abstract Liquid hydrogen (LH2) is a potential coolant of high-temperature superconducting (HTS) devices. However, owing to the high flammability of hydrogen and the risk of hydrogen embrittlement in ...materials, studies on LH2-cooled superconducting devices are rare. We developed an LH2 test apparatus to analyze the basic characteristics of LH2 as a coolant and evaluate the energizing characteristics of LH2-cooled superconducting wires. A REBCO external field coil was designed and manufactured for conducting cooling stability tests on various HTS coils cooled by LH2. The field coil, comprising eight single pancake coils of 4 mm wide REBCO wires, with inner diameter 106 mm and outer diameter 250 mm was divided into upper and lower sections. The test coil was placed in the central space. A magnetic field perpendicular to the test coil’s wire surface was generated by running currents in opposite directions through the upper and lower sections. Each double pancake coil was securely placed in a stainless-steel housing to withstand repulsive electromagnetic forces. The manufactured field coil was cooled using LH2, energized to 150 A, and successfully generated the intended magnetic field of 1.75 T. No increase in voltage was observed in any of the double pancake coils, and there was no mechanical degradation due to electromagnetic forces. Subsequently, we initiated thermal runaway tests on various HTS coils using the manufactured field coil to assess the cooling stability of LH2-cooled HTS coils. The study will facilitate the development of explosion-proof designs and safety technologies for LH2-cooled superconducting devices and cooling systems.
Evidence of the association between chronic low-grade inflammation, as reflected by C-reactive protein (CRP) measurements, and cancer risk is equivocal. Specifically, few studies have examined this ...in uncommon cancers and Asian populations.
We utilised a case-cohort design consisting of multi-types of cancer (N = 3608), and a random subcohort (N = 4432) in a Japanese large population-based study, with a median follow-up time of 15.6 years, and measured baseline plasma CRP using high sensitivity assay. The hazard ratios (HRs) were estimated using weighted Cox proportional hazards methods.
The multivariable-adjusted HR (95% confidence interval) for the top quartile of CRP was 1.28 (1.11‒1.48) (P
< 0.001) for overall cancer compared to the bottom quartile of CRP. Among site-specific cancers, higher CRP levels were associated with an increased risk of colorectal, lung, breast, biliary tract, and kidney cancer, and leukaemia. These positive associations remained among participants after >3 years' follow-up. Furthermore, subgroup analyses for overall cancer robustly showed a positive association with CRP levels, regardless of sex and obesity.
Our consistent findings suggested that chronic low-grade inflammation measured by CRP is associated with the risk of cancer.
Objectives
Extending healthy life expectancy (HALE), defined as the average number of years that a person can expect to live in “full health” by taking into account years lived in less than full ...health due to disease and/or injury, is a common topic worldwide. This study aims to clarify the relationships between the Mediterranean diet score (MDS) and life expectancy (LE) and HALE globally using publicly available international data.
Setting
Analyses were conducted on 130 countries with populations of 1 million or more for which all data were available. Individual countries were scored from 0 to 9 to indicate adherence to the Mediterranean diet according to the MDS scoring method. The supply of vegetables, legumes, fruits and nuts, cereals, fish, and olive oil per 1,000 kcal per country was calculated based on the Food and Agriculture Organization Corporate Statistical Database, with a score of 1 for above the median and 0 for below. The same method was used to calculate scores of presumed detrimental components (meat and dairy), with consumption below the median given a value of 1, and consumption above the median given a value of 0. For ethanol, a score of 1 was given for 10g to 50 g of consumption. We investigated the cross-sectional associations between the MDS and LE and HALE at birth in 2009, and the longitudinal associations between the MDS in 2009 and LE and HALE between 2009 and 2019, controlling for covariates at baseline using linear mixed models.
Results
In the cross-sectional analysis, the MDS was significantly positively associated with LE (β=0.906 95% confidence interval, 0.065–1.747, p=0.037) and HALE (β=0.875 0.207–1.544, p=0.011) after controlling for all covariates. The longitudinal analysis also revealed significantly positive associations between the MDS and LE (0.621 0.063–1.178, p=0.030) and HALE (0.694 0.227–1.161, p=0.004) after controlling for all covariates.
Conclusion
The present study, based on an analysis using 10 years of international data, showed that countries with a higher MDS showed a positive association with HALE.
Our research group has been researched for developing MgB2 superconducting energy apparatus in liquid hydrogen immersion cooling, such as superconducting generators. In this study, two-pole MgB2 ...race-track coil, which was a model for a few tens kVA superconducting generator field magnet, was designed and made. This coil consists of two pieces of a similar MgB2 race-track coil which has 529 turn with straight section of 150 mm, bending diameter in the end of section of 100 mm and thickness of 34 mm. We carried out excitation tests of the coil immersed in liquid hydrogen at the temperature of 21 K to 32 K, and the load line of the coil was obtained. The critical current under self-field was obtained for various temperatures. The normal zone propagation behavior of the coil at the quench was also investigated using several potential taps installed in the coil.
Superconducting Fault Current Limiters (SFCLs) are installed in the electric power system, and expected to limit fault current and improve system stability. In this paper, we focus on the transformer ...magnetic shielding type SFCL made of REBCO wires. This SFCL limits fault current mainly with reactance for small fault current. When fault current gets larger, resistance component is added and a larger impedance is generated. In this time, we fabricated the transformer type SFCL composed of pancake coils and investigated the basic characteristics. The pancake coil type has the advantage that the amount of superconducting wire is less and the size of SFCL becomes smaller than solenoid coil type. As the results of experiment, it was confirmed that SFCL limits fault current with reactance and resistance properly. Regarding the current limiting impedance, it almost agreed with the designed value, and confirmed the current limiting operation as expected.
We have been developing a conduction cooled 3T HTS(REBCO)-MRI system. The prototype system of 100 mm DSV (diameter spherical volume) was designed and made.The MRI image of a mouse fetus (25 mm long) ...was obtained successfully with 2.9 T under a power supply driven operation. However, the HTS(ReBCO)-MRI magnet still had a considerable magnetic field fluctuation for clear MRI imaging due to a long-lasting attenuation of screening current induced on the superconducting tapes. To solve this problem, we introduced a power supply system consists of a exciter power supply and a small trimming current supply, which compensates the magnetic field deviation due to the screening current, in parallel. We measured and evaluated the magnetic field stability of a commercial 3T-LTS-MRI magnet under both the power supply driven operation with proposed system and the persistent current operation. The availability of the power supply system was discussed using an experimental HTS-MRI system.
We present high stability of semi-transparent methyl ammonium (MA) lead triiodide perovskite (MAPbI3) solar cells with sputter–deposited polycrystalline NiOx hole transport layer (HTL) and indium tin ...oxide (ITO) back contact. We have demonstrated high thermal stability of the MAPbI3 perovskite devices with the NiOx HTL and glass encapsulations, showing no performance degradation at 85 °C over 1000 h in dark. They showed instability, however, under 1 sun illumination at ∼30 °C. Here, we demonstrate that the combination of the NiOx HTL and the ITO for both top and bottom electrodes of the perovskite solar cells can solve this instability problem. This approach resulted in highly stable semitransparent devices with the average visible light transmittance (AVT) above 11% and the power conversion efficiency (PCE) of 12.5%, showing steady power output nearly 4000 h of continuous operation at MPPT under 1 sun illumination. While the use of polybis(4-phenyl)(2,4,6-trimethylphenyl) (PTAA) HTL resulted in the semitransparent devices with higher PCE of 13.6%, their device stabilities were much inferior to the NiOx HTL based devices. These results indicated that a rather classical MA based perovskite, MAPbI3, is indeed a stable photovoltaic material with the proper choice of the interface layers and electrode materials, and the use of the sputter–deposited NiOx HTL together with the ITO back contact is one of the key elements to overcome the stability problem in the lead halide perovskite solar cells.
●Low-temperature processed semi-transparent perovskite (MAPbI3) solar cells were prepared using sputter deposited NiOx hole transport layer and ITO back contact.●Encapsulated solar cells maintain operational stability for 4000 h at the maximum power point tracking (MPPT) under 1 SUN illumination (no UV-light filtering) at 30 °C.●Side-by-side comparisons of the interface materials (NiOX or PTAA) and counter electrode materials (Ag or ITO) revealed that the combination of the NiOx and ITO was indispensable for attaining the high stability.
The operating temperature of a high-temperature superconducting (HTS) coil is desired to be 15-40 K from the viewpoint of specific heat of the material and the operating current. Development of ...relatively small-capacity coils with gas helium cooling or refrigerator cooling in this temperature range is underway. Here, refrigerant cooling is desirable for large-capacity coils and liquid hydrogen, which has 20.7 K atmospheric pressure saturation temperature, is a candidate refrigerant. However, due to the difficulty of handling hydrogen, there have been few studies on the HTS coil cooled by liquid hydrogen. And in the HTS coil, the heat generated in the normal conducting region causes a chain of temperature rise and decrease of the critical current, which leads to an irreversible increase in coil temperature beyond the balance with the cooling conditions, and so-called thermal runaway is a problem. In this study, we report on the observation of thermal runaway phenomena in Bi2223 coils under liquid hydrogen immersion cooling. The coils were energized twice at saturated condition of 950 kPa pressure and 30 K temperature. We observed thermal runaway in both energizations and the coil tap voltage before thermal runaway was several tens of mV. From this test, it could be said that the liquid hydrogen cooling has a potential to protect HTS coils.
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