An egg‐shaped diagram and its discrepancies in switched reluctance machines

Recently, switched reluctance motors have attracted attention from industries. It is a common practice to develop several test machines for performance evaluation. One way to make a comparison among several test machines is to draw an efficiency map in a speed and torque plane, but this is rather complicated. For an easy comparison, a machine parameter measurement with an egg‐shaped diagram has been proposed by the authors. In this method, it is possible to measure an inductance ratio, which indicates the saliency of switched reluctance machines. In this paper, a calculation of tolerance between theoretical egg‐shaped curves and measured powers is proposed. It is found that the tolerances are within 4% as a result of several test machines. Although discrepancies in instantaneous current waveforms and voltage phase angles are seen, the obtained machine parameters indicate an exact relation between input power and required apparent power. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(1): 61–71, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10286     

Epidemiological study of prevalence of genogroup II human calicivirus (Mexico virus) infections in Japan and Southeast Asia as determined by enzyme-linked immunosorbent assays

Mexico virus (MXV) is a genogroup II human calicivirus (HuCV). We conducted an epidemiological study to determine the prevalence of MXV infection in infants and adults in Japan and Southeast Asia by enzyme-linked immunosorbent assays (ELISAs) developed by using baculovirus-expressed recombinant MXV (rMXV) capsids. Of 155 stool specimens obtained from children younger than 10 years old with acute clinical gastroenteritis (diarrhea and vomiting) associated with small, round-structured viruses in Japan from 1987 to 1989, only 2 were positive for MXV antigen. In 42 outbreaks of acute gastroenteritis in Japan from 1986 to 1994, 1 in an infant home and 1 among adults were positive for MXV antigen. The pattern of acquisition of antibody to rMXV was different from that of acquisition of antibody to group A rotavirus, the prototype HuCV Sapporo virus, and Norwalk virus. The prevalence of antibody to rMXV remained low for the first 3 years of life, showed a steep rise during nursery school age, reaching a prevalence of 50%, and another steep rise during adolescence, reaching 80%; and steadily increased thereafter. A high prevalence of antibody (82 to 88%) was observed in adult populations in Japan and Southeast Asia, suggesting that MXV infection is common in these areas. The discrepancy between the high prevalence of antibody to MXV and a low rate of detection of MXV antigen may be explained by a high specificity of the antigen ELISA for the prototype and closely related MXV strains while serological responses can detect responses to a broader group of viruses.     

Quantitation of hepatitis G virus RNA in allogeneic bone marrow transplant recipients. Stem Cell Transplantation Team

In thermolysin, tryptophan 115 seems to be at the S2 subsite. Trp-115 was replaced with tyrosine, phenylalanine, leucine, and valine during site-directed mutagenesis in order to evaluate the role of Trp-115 in the proteolytic activity of thermolysin. The mutant enzymes with Tyr-115 or Phe-115 had as much proteolytic activity as the wild-type enzyme, but the other two mutant enzymes had no activity. We found earlier that the substitution of Trp-115 with alanine, glutamic acid, lysine, and glutamine causes the enzyme to lose all activity, so an aromatic amino acid at position 115 seems to be essential for thermolysin.     

Desorption of water adsorbed on iron oxide by laser irradiation

Desorption of water adsorbed on iron oxide by laser irradiation was studied by means of a time-of-flight (TOF) technique. The wavelength of the laser for desorption was varied from 355 to 600 nm. The energy threshold of the water desorption ranged around 2.0-2.3 eV. Based on the fact that this energy threshold approximately corresponds to the bandgap of Fe₂O₃, the initial process of water desorption is considered to be the electronic excitation of the iron oxide from the valence band to the conduction band. Analysis of the velocity distribution of the desorbed water suggests that following the electronic excitation of the iron oxide the desorption is caused by both thermal and nonthermal processes. The thermal process is caused by the rise of the surface temperature that occurs after the scattering and de-excitation of the excited electron in the iron oxide. In the case of the laser at λ = 355 nm, the desorption was mainly caused by the thermal process. On the other hand, in the case of the laser at λ = 430 nm, the desorption was mainly caused by the nonthermal process. The desorption caused by the nonthermal process is attributed to the transfer of the electron excited in the iron oxide to the adsorbed hydroxyl.     

A simple method for estimating carbonyl content in peroxide-containing oils

A simple method is described for the estimation of carbonyl content in peroxide-containing oils. In this method, peroxides, which interfere with carbonyl determination, are reduced with triphenyl phosphine prior to carbonyl determination. Carbonyl content is measured by a colorimetric 2,4-dinitrophenyl hydrazone procedure. Neither triphenyl phosphine nor triphenyl phosphine oxide, oxidation products of triphenyl phosphine by reaction with peroxides, interfere with the measurement of carbonyl content. The method is applicable to several kinds of oxidized oils in any oxidation stage.     

Upper and lower critical solution temperatures in polyethylene solutions

Upper and lower critical solution temperatures have been determined for solutions of polyethylene in n-butyl acetate and n-amyl acetate over the molecular weight range of M_η = 1·36 × 10⁴ to 17·5 × 10⁴. Polyethylene solution in n-butyl acetate displays a smaller miscibility region than that of the polyethylene/n-amyl acetate system, as indicated by the relative positions of their upper and lower critical solution temperatures. Contributions of the energy and the equation of state terms to the χ1 parameter have been examined by an application of the Patterson-Delmas corresponding state theory to the experimental results of the polyethylene solutions.