Analysis of magnetic bearing using inductive levitation by relative motion between magnet and conductor

In chemical plants, an anticorrosion magnetic drive pump is commonly used to deliver corrosive chemical liquids because of its high anticorrosion performance. However, when bubbles enter the chemical pump and accumulate between the shaft and the bearing, the shaft is often broken by thermal shock. The magnetic bearing which holds the rotor in noncontact has the advantage of avoiding thermal shock and keeping the rotor in a stable state by restoring force induced from the eddy current in the conductor. A model of magnetic bearing was analyzed using the three‐dimensional finite element method. In this model, a restoring force of 68.6 N and a braking torque of 8.7 N‐m were found. The locus of the rotation axis was also estimated using a radial load and a drag coefficient. The rotor may be located inside the movable range. ©2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 80–87, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20652     

Development of an identification system for location of free metallic particles in GIS based on analysis of Lamb waves

We investigated propagation properties of Lamb waves in a gas‐insulated switchgear (GIS) tank to diagnose insulation performance of GIS. The acoustic signals excited by a free metallic particle colliding with the tank sheath were measured using AE sensors. The wavelet transform was applied to decompose the wave data into its time–frequency components. As a result, difference of propagation properties of Lamb waves is clearly seen with different sizes of GIS tank. Based on the characteristics of Lamb waves, algorithms for location identification of a free metallic particle were examined in model GIS using two AE sensors. Herein, we propose a new system for location identification of a free metallic particle in GIS. Moreover, it is verified that the new identification system is suitable as a diagnostic technique for GIS. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(3): 28–35, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20676     

The Oxidation of Methane at Low Temperatures Over Zirconia-Supported Pd,Ir and Pt Catalysts and Deactivation by Sulfur Poisoning

Abstract  

The oxidation of methane over zirconia-supported Pd, Ir, and Pt catalysts at low temperatures under an oxidizing atmosphere and the effect of SO₂ on this reaction were investigated. An Ir–Pt/ZrO₂ catalyst exhibited high activity and low deactivation by SO₂. Characterization of the catalyst indicated the presence of a highly oxidized Pt species that was stabilized by the addition of Ir.     

Partially Coherent Imaging of a Straight-edged Object Associated with Periodic Structures of Acoustically Modified Spatial Coherence

Abstract

Spatial coherence of laser light can be modified by a progressive ultrasonic wave. The resultant optical mutual intensity has lateral and longitudinal periodicities in the near field behind the ultrasonic cell. Over the near field the longitudinal periodicity is lost in any plane parallel to the output plane of the cell but the lateral periodicity still remains. Such a plane serves as an object plane for partially coherent imaging. The imaging characteristics of an edge object, depending on various ultrasonic parameters, are described. Ringing suppression and contrast enhancement occur satisfactorily in the image if the ultrasonic parameters are properly controlled. Theoretical predictions are in good agreement with the experimental results.     

Immunostimulatory effect of β-cryptoxanthin in vitro and in vivo

Beta-cryptoxanthin (β-Crp), a mono-hydroxylated β-carotene, is a major dietary provitamin A xanthophyll. The immunostimulatory effect of β-Crp was examined using human hybridoma HB4C5 cells and mouse primary lymphocytes in vitro and using mice in vivo. IgM production by the HB4C5 cells and both IgA and IgG productions by mouse primary lymphocytes from mesenteric lymph node and spleen were accelerated in vitro by the treatment of β-Crp in dose-dependent manners. Afterwards 6-week-old female BALB/c mice were administered with a low or high dose of β-Crp for 14 days, mesenteric lymph node and spleen were excised and the immunoglobulin production levels were evaluated using lymphocytes from mesenteric lymph node and spleen in vivo. Results exhibited that all of IgA, IgG, and IgM productions by lymphocytes from mesenteric lymph node were increased. Especially, the IgG production increased with statistically significant differences in both of the low and high dose groups against the control group. The immunostimulatory effect on splenocytes was also observed although not as clear as on lymphocytes from mesenteric lymph node. Overall results suggest that β-Crp may stimulate the humoral immunity in mammals. Hence, β-Crp might have a potentially significant impact on human health and on prevention of diseases.     

Performance of graphite filled composite based on benzoxazine resin

In this study, we aimed to prepare and characterize graphite filled composites based on benzoxazine resin for the bipolar plate in fuel cell. Three kinds of graphite (synthetic graphite, natural graphite, and expanded graphite) were used for the preparation of the graphite filled composites. The composites were prepared by means of the compression molding of mixtures of graphite and benzoxazine resin. The properties of the graphite filled composites based on benzoxazine resin were estimated by mechanical property, gas permeability, and electrical conductivity. As a result, it was found that graphite filled composites based on benzoxazine resin showed good gas impermeability, electrical conductivity and mechanical property compared with those of the graphite filled composites based on the conventional phenolic resin. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Glass fiber‐reinforced composite based on benzoxazine resin

In this study, we aimed to prepare and characterize glass fiber‐reinforced composites (GFRP) based on benzoxazine resins. Therefore, the molten resin from benzoxazine and bisoxazoline with the latent curing agent was used as the matrix resin, and the properties of GFRP based on the molten resins were investigated. The properties of GFRP were estimated by mechanical properties, heat resistance, and flame resistance. As a result, it was found that GFRP based on the molten resins from benzoxazine and bisoxazoline with the latent curing agent showed good heat resistance, flame resistance, and mechanical properties compared with those of the conventional GFRP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preliminary studies for interaction of a cyclobutane thymine dimer region with its cognate antibody

A monoclonal antibody (TDM-2) specific to a UV-induced cyclobutane pyrimidine dimer has previously been established. We investigated here the structural requirements of antigen recognition by the antibody using chemically synthesized antigen analogs. TDM-2 bound to the cis-syn, but not the trans-syn thymine dimer, and recognized not only the cyclobutane ring but also the 5'- or 3'-side phosphate groups flanking the cyclobutane dimer site. The antibody showed strong binding to photodimer-containing single stranded DNA but indicated little binding to double stranded DNA.     

Subcutaneous loperamide prevents gastric lesions induced by necrotizing agents in rats

The effects of subcutaneous loperamide on gastric lesions induced by necrotizing agents were investigated in the rat. Loperamide produced a dose-dependent increase of gastric fluid volume and inhibition of gastric lesions caused by 0.6 N HCl or absolute ethanol. Pretreatment with naloxone almost completely blocked both fluid pooling effect and mucosal protective effect of loperamide. Omeprazole reduced the acidity of the gastric fluid in rats treated with loperamide without significantly decreasing the fluid volume. Various volumes of acid, given orally immediately before 0.6 N HCl, volume-dependently prevented gastric lesions. We conclude that subcutaneous loperamide protects the gastric mucosa against necrotizing agents through luminal dilution of irritants, which is mediated by naloxone-sensitive opiate receptors.