Numerical simulation of particle motion in vibrated fluidized bed

The particle motion in vibrated fluidized bed was examined by using numerical simulation. A two-dimensional fluidized bed was used, and discrete element method (DEM) was used as for calculating the particle motion in vibrated fluidized bed. Geldart group B particle, which is regarded to have no effect of agglomerate, was used as the fluidizing particle. The vibration directions (vertical and horizontal) and vibration parameters (frequency and amplitude of vibration) were changed.In the case with vertical vibration, large bubbles caused by vibration gap (defined as the gap between particle bed and wall caused by vibration) appear in bed. When the vibration strength is high and the vibration frequency is low, it is difficult to fludize the particle bed in the case with horizontal vibration because the vibration gap acts like the channel. When the vibration frequency increases at the same vibration strength, the effect of vibration on the particle motion becomes small. The effect of vibration on the pressure loss in particle bed is large in the case with horizontal vibration.     

Self‐Organized Superlattice and Phase Coexistence inside Thin Film Organometal Halide Perovskite

Organometal halide perovskites have attracted widespread attention as the most favorable prospective material for photovoltaic technology because of their high photoinduced charge separation and carrier transport performance. However, the microstructural aspects within the organometal halide perovskite are still unknown, even though it belongs to a crystal system. Here direct observation of the microstructure of the thin film organometal halide perovskite using transmission electron microscopy is reported. Unlike previous reports claiming each phase of the organometal halide perovskite solely exists at a given temperature range, it is identified that the tetragonal and cubic phases coexist at room temperature, and it is confirmed that superlattices composed of a mixture of tetragonal and cubic phases are self‐organized without a compositional change. The organometal halide perovskite self‐adjusts the configuration of phases and automatically organizes a buffer layer at boundaries by introducing a superlattice. This report shows the fundamental crystallographic information for the organometal halide perovskite and demonstrates new possibilities as promising materials for various applications.     

Human aldolase B: liver-specific properties of the isozyme depend on type B isozyme group-specific sequences

A series of chimeric enzymes between two human aldolases A,B or C were constructed to identify the molecular regions responsiblefor isozyme-specific functions. Chimeras constructed betweenaldolases A and B were AB34 (an AB chimera connected at position34), ABA34–306 and ABA212–306 (the ABA chimeras).Those between aldolases B and C are BC243, BC263 and BC306 (theBC chimeras connected at positions as indicated), as well asCB55, CB243, CB263 and CB306 (the CB chimeras connected at positionsas indicated), CBC55–263 (a CBC chimera), and BCB55–193,BCB55–306, BCB79–193 and BCB79–306 (the BCBchimeric enzymes). Through the analysis of the properties ofthese chimeras, it was found that for aldolase B, isozyme Bgroup-specific sequences (IGSs)-l and-4 were required for exertingtype B-specific functions, while the IGSs-2 and -3 enhanced,in collaboration with the IGS-1, the catalytic activity of aldolaseB. In addition, the /ß-barrel and the restricted stretches,which were not specified but occupied two distinct regions spanningthe amino acid positions 108–137 (designated connector1) and 243–306 (designated connector 2), were found tobe indispensable for showing full catalytic activity of aldolaseB.     

Development of a short-term emergency assessment system of the marine environmental radioactivity around Japan*

The Japan Atomic Energy Agency (JAEA) has, for many years, been developing a radionuclide dispersion model for the ocean, and has validated the model through application in many sea areas using oceanic flow fields calculated by the oceanic circulation model. The Fukushima Dai-ichi Nuclear Power Station accident caused marine pollution by artificial radioactive materials to the North Pacific, especially to coastal waters northeast of mainland Japan. In order to investigate the migration of radionuclides in the ocean caused by this severe accident, studies using marine dispersion simulations have been carried out by JAEA. Based on these as well as the previous studies, JAEA has developed the Short-Term Emergency Assessment system of Marine Environmental Radioactivity (STEAMER) to immediately predict the radionuclide concentration around Japan in case of a nuclear accident. Coupling the STEAMER with the emergency atmospheric dispersion prediction system, such as Worldwide version of System for Prediction of Environmental Emergency Dose Information version II (WSPEEDI-II), enables comprehensive environmental pollution prediction both in air and the ocean.     

Performance and maximum load capacity of uninterruptible power system using double‐layer capacitor

Power service interruptions cause problems in various facilities. Even an instantaneous voltage drop may give rise to serious problems in computer systems or electronic equipment. The uninterruptible power system (UPS) has been used to compensate for the power service interruptions. Also, the instantaneous voltage drop compensator using the electrolytic capacitor has been developed for the instantaneous voltage drop. Recently, the double‐layer capacitor has been considered as a new energy storage element. This capacitor has many advantages such as no maintenance, long lifetime, and quick charge/discharge characteristics with large current and it has higher energy density than the electrolytic capacitor. Therefore, we developed the UPS using the double‐layer capacitor. In this paper, the performance of the UPS using the double‐layer capacitor is shown by simulated and experimental results. Furthermore, the discharge characteristics of the double‐layer capacitors are investigated on the basis of the equivalent circuit including the capacitors and a voltage booster. Finally, the maximum load capacity to compensate is clarified for the system. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(3): 73–81, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20190     

Approaches to suppressing shaft voltage in brushless DC motor driven by PWM inverter

This paper describes the approaches to suppressing the shaft voltage and bearing current by electrostatically shielding the stator end windings of the brushless DC motor driven by PWM inverter. At first, measured shaft voltage and bearing current are compared with those calculated waveforms to verify the common mode equivalent circuit of the brushless DC motor. Next, the relationship between shaft voltage and stator winding to rotor capacitance is calculated using the common mode equivalent circuit. Finally, the electrostatic shielding of the stator end windings is evaluated to reduce the shaft voltage by experiments and calculations. ©2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 73–79, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20701     

Thermal degradation of carboxylate‐based polyurethane anionomers

With the purpose of elucidating the thermal degradation process of carboxylated polyurethane anionomers (PUAs), characterization of PUAs containing potassium and magnesium salts was conducted using thermogravimetry and FTIR spectroscopy. Potassium salt in PUA induced pronounced acceleration on the thermal degradation of urethane linkage in the hard segment as well as ester and carbonate linkages in the soft segment. The absorption bands of ν(N? H), ν(C=O), δ(N? H), ν (C? N), and ν(C? O? C) in FTIR spectra of PUAs recorded as a function of increasing temperature demonstrated abrupt changes around the initial thermal decomposition temperature, making possible comprehensive studies of the thermal degradation process of PUAs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 573–579, 2006     

Effects of fullerene derivatives on the gas permeability of thermoplastic polyurethane elastomers

In an effort to improve the gas barrier properties of thermoplastic polyurethane (TPU) elastomers, fullerene derivatives were added as fillers, and the resulting O₂ and CO₂ permeabilities were analyzed. The addition of 5 wt % polyhydroxylated fullerene {fullerenol [C₆₀(OH)_n] mixture, where n = 6–12} decreased the gas permeability by approximately 10–20%. According to the hole volumes computed with the results from positron annihilation lifetime spectroscopy, the addition of fullerene derivatives did not produce any changes in the hole volumes of the TPUs. Thus, the reduction in the TPU gas permeability was not caused by changes in the hole volumes. Instead, an inhibited diffusion of gas molecules by fullerene particles was deduced as the cause of the decrease in gas permeability from changes in the diffusion coefficient with temperature. The addition of urethanized fullerene, prepared through the chemical modification of fullerenol, markedly affected the TPU gas barrier properties. As compared to fullerenol addition, the gas barrier properties improved approximately fourfold for O₂ and approximately fivefold for CO₂. These results suggest that the dispersability of urethanized fullerene in TPU was higher than that of fullerenol. We found that the gas barrier properties were independent of the structure of polyol. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39986.     

Quantitative analysis of the influence of conductors and ferromagnetic structures in power facilities on an ELF magnetic field environment using the finite element method

Recently, electric power transmission/substation systems need to be extended and they tend to be more compact. From the backgrounds of electromagnetic field environment, especially the magnetic field environment in and around electric power facilities becomes more important. However, many factors must be considered when investigating it, such as complicated current conditions, configurations of conductors and ferromagnetic structures, and so on. For more precise investigation of magnetic field environments, we must understand the quantitative influence of conductors and ferromagnetic structures. In this paper we describe how conductive and ferromagnetic materials influence the ELF magnetic field distribution. We carried out the measurement and finite element analysis of magnetic flux density distribution around an aluminum plate, a soft magnetic iron plate, and a 1/40 reduced model of an actual transmission tower. Based on the results, we clarified the influence of conductors and ferromagnetic substances on the magnetic flux density distribution around them. Finally, we showed the effectiveness of finite element analysis for evaluating the magnetic field around actual power facilities. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 44–52, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10021     

Superconducting compact synchrotron light source

A superconducting compact synchrotron light source, the NIJI-III, has been completed. The development of the NIJI-III was assigned to Sumitomo Electric Industries Ltd. by the Research Development Corporation of Japan and was deemed successful in October 1991 with the attainment of the design goal of the stored beam current of 200 mA at the final beam energy of 600 MeV. The lattice has a four-sector configuration: four superconducting bending magnets and eight quadrupole magnets, achieving the optimum beam characteristics for lithography. The world's first superconducting bending magnet was developed and adapted, and was characterized by a cosθ type without an iron, a large bore of 200 mm, and a strong curvature of 0.5 m. Furthermore, a newly developed vacuum system and an rf system were installed. The high-speed electron-beam wobbling method was investigated at a 20-Hz triangular wave for the exposure of the vertical field of synchrotron light. It was demonstrated that the expansion of the vertical exposure area agreed with the theoretical calculation, and that there was no effect on the beam lifetime. The achievement of the NIJI-III can be expected to contribute much to the development of various research applications of synchrotron light.