Development of magnesium composite alloy by a new method combining B2O3 addition and melt stirring

For developing high performance magnesium alloys, a new method in combination of B2O3 addition and melt stirring was applied. When 0.3%, 6% and 12%（ mass fraction） B2O3 was added into pure Mg, many twins were produced in each alloy. The average grain size of Mg was about 200 μm. In Mg-6Al alloy, the grain size is decreased from 50 to 35 μm by B2O3 addition. In Mg-6RE （rare earth） alloys, the grain size is decreased from 35 to 15 μm. The grain size of Mg-9Al- 6Ti-3B2O3 alloy is about 5 μm. The hardness of pure Mg does not change by B2O3 addition. In Mg-6Al alloy, the hardness is increased by addition of 3% B2O3, however, the hardness of Mg-6RE alloy is decreased by B2O3 addition. Addition of B2O3 into Mg-Al, Mg-RE and Mg-Al-Ti alloys makes the fine grain structures, the hardness of Mg-RE alloy is decreased. This strange behavior may be interpreted with existence of many fine pores in the alloy. The mechanical properties of composite Mg-9Al-6Ti with 3?O3 are higher than those of AZ91C. The present results demonstrate the potential of this new method for developing high performance magnesium alloys.     

Winding Method to Reduce Vibration and Loss Caused by Fractional Slot of Synchronous Machine

Fractional‐slot windings are widely used in rotating machines in order to improve the output voltage waveform, increase the design flexibility, and gain many other advantages. However, fractional‐slot windings are known to produce different harmonic components such as an even order and/or fractional number of space flux harmonics compared to integral‐slot windings. These harmonics may increase stray losses and cause stator core vibration. This paper describes an analysis of space flux harmonics and proposes new winding methods such as “novel interspersed windings” to reduce these harmonic components. The proposed winding methods were verified by numerical analysis and model tests.     

Enlargement of Claw Pole Motor Using SMC Cores Divided in the Circumferential Direction

Clawtooth motors have the feature that they can be made thin in the axial direction. This makes them suitable for appliances, automobile accessories, and small‐sized industrial motors. On the other hand, there is a need for thinner HEV and elevator motors and large‐sized industrial motors. In this study, we examined ways of increasing the output of clawtooth motors. We arrived at the following conclusions. (1) The optimal stator structure was determined and the prospects of attaining the target specification of 123 N‐m were determined. (2) Three important manufacturing tasks, assurance of core assembly accuracy, thin coil manufacture, and rotator insertion, were identified. (3) Experimental results and the results of analysis were in agreement with respect to the EMF. (4) The experimental cogging torque results and finite element analysis (FEA) results were in agreement with the FEA results at sixth order but not at second and fourth order. (5) Although the core needed to be divided in the circumferential direction in order to increase its size, it was clear that the influence on the torque was small. (6) Use of a divided core is a good solution for enlargement of clawtooth motors.     

Simple evaluation of aortic arch calcification by chest radiography in hemodialysis patients

Vascular calcification is associated with a poor prognosis in dialysis patients. It can be assessed with computed tomography but simple inoffice techniques may provide useful information. We compared the results obtained with a simple noninvasive technique with those obtained using multidetector computed tomography for aortic arch calcification volume (AoACV) in chronic hemodialysis (HD) patients. The enrolled study subjects were 63 (32 men and 31 women) maintenance HD patients. Calcification of the aortic arch was semiquantitatively estimated with a AoAC score (AoACS) on plain chest radiology. The AoACV was increased, with a mean value of 6.6 ranging from 0% to 36.5%. The coefficient of intraobserver variation was less than 2.5%. Aortic arch calcification score was highly correlated with AoACV (r=0.635, P<0.001). Multiple regression analysis showed age (F value=12.62, P<0.001) and pulse pressure (F value=4.54, P=0.037) to be significant independent determinants of AoACS. In conclusion, a simple measurement of AoACS may be useful for inoffice imaging to choose a therapeutic regimen in HD patients.     

Influence of sub-micrometer notches on the fracture of single crystal silicon thin films

The influence of notches on the fracture of single crystal silicon thin films was investigated. The tests were conducted on notched and smooth tensile specimens micromachined on a silicon wafer. The specimen geometry was 100 μm long, 50 μm wide and 5 μm thick. For the notched specimen, a V‐shaped sub‐micrometer notch was introduced on one edge of it by using a focused ion beam (FIB) process. The notch lengths ranged from 0.07 to 1.3 μm. Four types of specimens with different surfaces and tensile orientations were tested. The smooth specimens showed scattered fracture strengths and ‘collapsed’ fractures. For the restrictive‐shaped notches, the critical length was 0.5 μm. The short‐notched (<0.5 μm) specimens also showed ‘collapsed’ fractures, and the stress concentrations on notch tips decreased their fracture strengths. For the long‐notched (>0.5 μm) specimens, the notch was equivalent to a crack in the Griffith model and the crack mainly propagated on {111} cleaved planes.     

A new methodology to guarantee the structural integrity of Al2O3/SiC composite using crack healing and a proof test

Structural ceramics are brittle and sensitive to flaws. As a result, the structural integrity of a ceramic component may be seriously affected by inherent flaws. Self-crack-healing is an excellent answer to this problem. At the moment, however, there is no technique to heal embedded flaws. Therefore, a technique to guarantee the reliability of ceramic components is demanded, and thus a technique using crack healing followed by proof test was developed by K. Ando et al. to accomplish this. With this technique, testing the mechanical behaviour of the crack-healed zone is very important for ensuring the structural integrity of a ceramic component. In this study, first Al₂O₃/SiC composite with an excellent crack-healing ability was sintered. Second, a crack was introduced on the sample (3 mm × 4 mm × 36 mm), which reduced the bending strength by about 80%, and subsequently the crack was healed. Third, a proof test was carried out on the crack-healed sample. Last, using the crack-healed and proof-tested sample, a fracture test was carried out up to 1373 K. The measured minimum fracture stress (σ_Fmin) was compared with the theoretical minimum strength (σ_G) from room temperature (R.T.) to 1373 K. It was concluded that σ_G showed good agreement with σ_Fmin up to 1373 K and that the crack healing followed by proof test was an excellent technique to increase the survival probability by administering a proof test and to guarantee the reliability of Al₂O₃/SiC composite.     

Low-Molecular Weight Components in Sarcoplasm Promoting the Color Formation of Processed Meat Products

Possible endogenous components having a promoting effect on the color formation of processed meat products were identified from two subfractions, B and C, in the low-molecular weight sarcoplasm fraction. Thin-layer chromatography indicated that subfraction B contained GSH, ATP and IMP, while subfraction C contained IMP and ribose. The presence of GSH and IMP in subfraction B was confirmed by the ultraviolet absorption spectra. GSH promoted the color formation and the decomposition of nitrite in both aqueous model and meat systems. The promoting effect was remarkable in the former system. ATP, IMP and ribose enhanced CFA when added with GSH to the meat system. This suggests that the combined action of these identified endogenous components contribute to the color formation of processed meat products in the rapid curing process.     

Preventive approach against drug-induced pulmonary fibrosis through the suppression of epithelial-mesenchymal transition

A number of drugs induce pulmonary injury and subsequently lead to serious lung diseases such as pulmonary fibrosis as the adverse drug reactions. However, an effective preventive approach against drug-induced pulmonary fibrosis has not been established due to poor understanding of common preventive targets in a variety of drugs showing pulmonary toxicity. Epithelial-mesenchymal transition (EMT), a cellular phenotypic change of the epithelial to mesenchymal state, contributes to the development of pulmonary fibrosis through the conversion of damaged alveolar epithelium into myofibroblasts. As several drugs with pulmonary toxicity have been reported to induce EMT, EMT serves as a bridge between the drugs and pulmonary fibrosis. Accumulated evidence supports the potential of EMT as a preventive target against drug-induced pulmonary fibrosis. Additionally, since there are mechanistic differences between the main pharmacological effect and EMT induced by the drug, prevention based on EMT suppression would be possible and would contribute to continuous clinical treatment with the drug to avoid EMT-mediated serious pulmonary fibrosis. Furthermore, targeting EMT seems to be adequate for exerting a preventive effect since EMT in damaged alveolar epithelial cells occurs prior to the development of the pathophysiological state of the whole lung in a bleomycin-induced lung injury rat model. This viewpoint deals with the benefits and perspectives of preventive approaches against druginduced pulmonary fibrosis through the suppression of EMT, which has rarely been addressed.     

Dyeing Properties of Reactive Cationic Dyes Containing a Vinyl-sulphonvl Group on Acrylic Fibre Blends

The preparation of reactive azo cationic dyes containing a vinylsulphonyl group derived from 2-aminobenzothiazole and its derivatives is described. Their dyeing properties on blends of acrylic–cellulosic, polyester–cellulosic fibre and on cotton and synthetic fibres are investigated. The relationship between absorption spectra and pH of dye solution is assessed.