•The effect of the condenser temperature was studied on the thermal performance.•A cryogenic heat pipe could be utilized even in the local dry-out state as a heat-transfer device.•The operation of a ...cryogenic heat pipe in local dry-out state resulted in large heat transfer capability.•The cryogenic parallel heat pipe system with Ne-, N2-, and Ar-heat pipes was experimented.•The cryogenic parallel heat pipe system can expand the operating temperature range.
In this study, we experimentally investigated the thermal behavior of a cryogenic parallel heat pipe system, which comprises a parallel arrangement of an N2-heat pipe and Ar-heat pipe or an N2-heat pipe and Ne-heat pipe. The heat pipes in the parallel system have common evaporator and condenser sections. We conducted preliminary experiments to investigate the individual thermal performance of heat pipes considering three working fluids, which formed the basis for analyzing the parallel heat pipe system. The experiments were performed at several condenser temperatures between 27 and 110 K for a wide range of heat loads considering various heat pipe operating states, such as the normal heat pipe operation, local dry-out, and locally frozen states. Although the tested heat pipes, manufactured by Fujikura Electronics (Thailand) ltd., were commercial heat pipes for room temperature applications, which use water as a working fluid, the working fluid was replaced with nitrogen, argon, or neon in the present experiments. The heat pipes used a composite wick comprising axial grooves and sintered metal powders. The experimental results verify that the heat pipe can be utilized even in the local dry-out state or locally frozen state. Moreover, the parallel heat pipe system can enhance the thermal performance with respect to the maximum heat transport capability, which was 29 W at an operating temperature of 87 K, and expand the operating temperature range to 24–150 K. The proposed parallel heat pipe system can be used to improve the cooling system of superconducting magnets and in other cryogenic applications.
To evaluate the effect of overfeeding on fatty acid distribution and metabolism, especially stearoyl-CoA desaturase-1 (SCD-1) indices, 8 cats in the experimental and control groups (4 per group) were ...evaluated in this study. The experiments involved feeding the experimental group cats twice their daily energy requirement with a commercial diet for 4 weeks. The control group was fed the estimated daily energy requirement with the same diet. Body weight, feline body mass index, body condition score, several zoometry measurements, and plasma metabolites/hepatic injury markers were measured in all the cats before and after the experiment. In addition, the fatty acid profiles in the liver and subcutaneous adipose tissue were measured after the experiment. After 4 weeks of overfeeding, the experimental group demonstrated significant increases in hepatic C18:1, plasma triglyceride, and nonesterified fatty acid (NEFA) concentrations and in alanine aminotransferase activity. Furthermore, hepatic SCD-1 indices were positively correlated with body weight, feline body mass index, body condition score, and plasma NEFA concentration, although subcutaneous adipose tissue did not demonstrate any increase in SCD-1 indices in this study. The increase in hepatic SCD-1 indices might be enhanced by the inflow of plasma NEFA into the liver, and NEFA toxicity might stimulate C18:1 synthesis by SCD-1.
Cryogenic mirrors have been introduced to the KAGRA gravitational wave telescope in Japan and are also planned to be used in next-generation gravitational wave telescopes to further improve their ...sensitivity. Molecular gases inside vacuum chambers adhere to cold mirror surfaces because they lose their kinetic energy when they hit cryogenic surfaces. Finally, a number of adsorbed molecules form an adlayer, which will grow with time. The growing adlayer functions as an optical coating and changes the properties of the underlying mirror, such as reflectance, transmittance, and absorption, which are carefully chosen to maximize the detector sensitivity. The adlayer possibly affects the gravitational wave detector sensitivity. To characterize these changes, a high-finesse Fabry-Perot cavity was introduced to a KAGRA cryostat, and the finesse of the cavity was monitored for 35 days under cryogenic conditions. We confirmed that the molecular adlayer was formed on a cold mirror and caused an oscillation in the finesse. The real and imaginary parts of the refractive index of the adlayer were 1.26 ± 0.073 and 2.2 × 10−7 ± 1.3 × 10−7, respectively. These are considered to be those of H2O molecules. The formation rate of the molecular adlayer was 27 ± 1.9 nm/day . In this paper, we describe theoretical and experimental studies of the formation of a molecular adlayer on cryogenic mirrors. Furthermore, the effects of a molecular adlayer on the quantum noise and the input heat to the test mass are also discussed.
Multidrug resistance has been a critical issue in current chemotherapy. In Escherichia coli, a major efflux pump responsible for the multidrug resistance contains a transporter AcrB. Crystallographic ...studies and mutational assays of AcrB provided much of structural and overall functional insights, which led to the functionally rotating mechanism. However, the drug uptake pathways are somewhat controversial because at least two possible pathways, the vestibule and the cleft paths, were suggested. Here, combining molecular simulations and site-directed mutagenesis experiments, we addressed the uptake mechanism finding that the drug uptake pathways can be significantly different depending on the properties of drugs. First, in the computational free energy analysis of drug movements along AcrB tunnels, we found a ligand-dependent drug uptake mechanism. With the same molecular sizes, drugs that are both strongly hydrophobic and lipophilic were preferentially taken in via the vestibule path, while other drugs favored the cleft path. Second, direct simulations realized totally about 3500 events of drug uptake by AcrB for a broad range of drug property. These simulations confirmed the ligand-dependent drug uptake and further suggested that a smaller drug favors the vestibule path, while a larger one is taken in via the cleft path. Moreover, the direct simulations identified an alternative uptake path which is not visible in the crystal structure. Third, site-directed mutagenesis of AcrB in E. coli verified that mutations of residues located along the newly identified path significantly reduced the efflux efficiency, supporting its relevance in in vivo function.
The aim of this study was to evaluate butyrate supplementation of antibiotic‐free milk replacer and starter on growth performance in male Holstein calves. Twenty‐nine calves were divided into two ...groups. Group C (n = 13) was fed antibiotic‐free milk replacer without supplementation, and Group B (n = 16) was fed antibiotic‐free milk replacer supplemented with butyrate (1.6 % DM of Gustor BP70®). Starter in Group B contained 0.3 % DM of Gustor BP70®. The intake of milk replacer was lower in group B than in C (p = 0.07 for the treatment x week interaction). Body weight (BW) and heart girth (HG) in group B was higher than in C during the experimental period (p = 0.07 and 0.01 for the treatment × week interaction, respectively). The duration of the weaning period in group B was shorter than in group C (p = 0.02). β‐hydroxybutyrate (BHBA) was higher in group B than in C (p = 0.04). Insulin like growth factor‐1 (IGF‐1) concentrations tended to be higher in group B than in C (p = 0.07 for treatment × week interaction). Our results show that butyrate supplementation in antibiotic‐free milk replacer and starter exerted positive effects on growth performance in suckling calves.
In collaboration with CERN, High Energy Accelerator Research Organization (KEK) has designed and developed short-scale model magnets of the beam separation dipole, MBXF, which will be installed for ...the High Luminosity Large Hadron Collider, HL-LHC. A new quench protection heater for MBXF was designed and tested during the cold test of the short-scale models. Combining data taken since the test of the 1st model magnet, we confirmed the maximum hotspot temperatures are well below 300 K in the case of the low field (1 T) and high field (5 T) quenches, respectively. In addition, a simulation model was developed and tuned with the obtained data for the full-scale prototype magnet. The hotspot temperature after quench initiation was then computed with the new heater circuit and found to be below 300 K even for the case of failure in firing the heater.
Nb-Ti based large-aperture beam separation dipoles (MBXFs) will be installed on both sides of two interaction points, ATLAS and CMS, for the high-luminosity LHC upgrade. The most important ...requirements for MBXF is a coil aperture of 150 mm and the field integral of 35 T·m. Nominal dipole field is 5.6 T at 12 kA and 1.9 K. KEK is in charge of developing MBXF within a framework of CERN-KEK collaboration. This study reports training performance of three 2-m long model magnets (MBXFS1-3) assembled under different mechanical support conditions. Azimuthal pre-stress both in the straight section and at coil end, and axial pre-load were controlled to counteract Lorentz force. In MBXFS2 and 3, wet-winding was also applied but solely to the coil end. Quench start locations for the model magnets are compared to validate the effectiveness of each support method.
In the present study, the production of propylene oxide (PO) from propylene via gas-phase epoxidation was investigated using various catalysts. Although Ag is known to be a highly active catalyst for ...the epoxidation of ethylene, it was not active in the present reaction. Both Al and Ti showed high levels of activity, however, which resulted in confusion. The present study was conducted to solve such confusion. Although the employment of MCM-41 modified with Ti and/or Al was reported as an active catalyst for epoxidation, the combination resulted in the formation of PO at a less than 0.1% yield. Since this research revealed that the acidic catalyst seemed favorable for the formation of PO, versions of ZSM-5 that were both undoped and doped with Na, Ti, and Ag were used as catalysts. In these cases, small improvements of 0.67% and 0.57% were achieved in the PO yield on H-ZSM-5 and Ti-ZSM-5, respectively. Based on the results of the Ti-dopant and acidic catalysts, Ag metal doped on carbonate species with a smaller surface area was used as a catalyst. As reported, Ag‒Na/CaCO3 showed a greater yield of PO at 1.29%. Furthermore, the use of SrCO3 for CaCO3 resulted in a further improvement in the PO yield to 2.17%. An experiment using CO2 and NH3 pulse together with SEM and TEM examinations for Ag‒Na/CaCO3 revealed that the greatest activity was the result of the greater particle size of metallic Ag rather than the acid‒base properties of the catalysts.
KEK has been developing a beam separation dipole magnet for the high luminosity large hadron collider upgrade. The magnet has a coil aperture of 150 mm and uses NbTi superconducting cable. A dipole ...magnetic field of 5.6 T is generated at 12 kA at 1.9 K to provide a field integral of 35 T·m. KEK has started the development of the first 2-m-long model magnet to evaluate the design and performance of the beam separation dipole magnet. The excitation test at 1.9 K of the first 2-m-long model magnet was performed from April to June 2016 at KEK. This paper presents the results of the magnetic field measurements of the first 2-m-long model magnet by a rotating coil probe.
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