INITIATION AND GROWTH OF SMALL CRACKS IN DIRECTIONALLY SOLIDIFIED MAR-M247 UNDER CREEP-FATIGUE. PART I: EFFECT OF MICROSTRUCTURE

This paper deals with the initiation and growth of small cracks in a directionally solidified superalloy, Mar-M247.     

Image-transmission of radiotherapy planning using 64kbps-ISDN videophone

We carried out the image-transmission using the 64kbps-ISDN and two terminals of the videophone installed in Osaka Teishin Hospital and Department of Radiation Oncology, Biomedical Research Center, Osaka University Medical School. The frame speeds (sec./frame) of the videophone are 1.2 for standard resolution with 320 x 200 matrix and 5.0 for high resolution with 640 x 400 matrix. Although the image with 640 x 400 matrix is not enough for the radiation diagnosis such as the chest radiogram, the image is useful for the radiation therapy planning. This system is easy to operate, and will be widely distributed in near future.     

JTE-607, an inflammatory cytokine synthesis inhibitor, attenuates ischemia/reperfusion-induced renal injury by reducing neutrophil activation in rats

Renal ischemia/reperfusion (I/R) injury is one of the main causes of postoperative renal failure. Activated neutrophils are implicated in the development of I/R-induced renal failure. JTE-607 has been reported to be a potent inhibitor of the multiple inflammatory cytokines in the endotoxic shock mouse model and heart Langendorff perfusion model. In this study, we examined whether JTE-607 attenuates I/R-induced renal injury by reducing neutrophil activation. Male wistar rats were intravenously administered JTE-607 (JTE group, 30 mg/kg) or 5% mannitol (control group) 30 min before ischemia. JTE-607 reduced the I/R-induced increases in the serum concentrations of blood urea nitrogen and creatinine, and improved the histopathologic changes, including acute tubular necrosis. I/R-induced an increase in neutrophil activation, reflected by increases in renal cytokine-induced neutrophil chemoattractant (CINC)-1 and myeloperoxidase (MPO) concentrations which were significantly reduced by JTE-607. These findings indicate that JTE-607 attenuates I/R-induced acute renal injury, probably by inhibiting neutrophil activation. JTE-607 might be a novel therapeutic strategy for the protection of postoperative renal failure in surgery associated with renal ischemia as well as renal transplantation.     

Pressure apparatus of split-octahedron type for x-ray diffraction studies

An apparatus of split-octahedron type has been developed for the study of x-ray diffraction at high pressure. The apparatus consists of a cylinder, a sphere, and an octahedron, all split up and assembled in a multistaged arrangement. Three ways of splitting the innermost octahedron are utilized in matching the cell geometry to the standard camera method. High pressures in excess of 220 kilobars can be generated in the center of the split octahedron by using a composite mixture of diamond powder and epoxy resin as a pressure-transmitting medium. The pressures required for the semiconductor-to-metal transitions of ZnTe, ZnS, GaAs, and GaP are determined by simultaneously monitoring the electrical resistance of the semiconductors and the lattice parameter of sodium chloride.     

Preparation and the catalytic activity of novel Pd nanocluster catalysts utilizing an oligosilsesquioxane ligand

Palladium acetate together with a newly synthesized silsesquioxane- pyridyl ligand showed excellent catalytic activity towards the aerobic oxidation of benzyl alcohol to benzaldehyde. TEM measurements revealed the in situ formation of Pd nanoclusters during the reaction period.     

Strain rate dependency on stress–strain relations of polypropylene

True constant strain rate tensile tests of polypropylene up to 2% initial strain were performed to investigate the strain rate dependency of the initial stress–strain gradient dσ/dε with the aid of “slack grip.” The experimental results fairly agree with even the simplest mechanical model analysis with three parameters, showing the conspicuous strain rate dependency on the initial stress–strain gradient dσ/dε. The limiting cases corresponding to zero strain rate and strain rate of infinite magnitude, both predicted by the analysis, were experimentally verified.     

Basic investigation for life assessment technology of modified 9Cr–1Mo steel

In order to develop life assessment techniques for aged components made of modified 9Cr–1Mo steel, specimens were artificially deteriorated by aging, creep and fatigue tests at elevated temperatures, and associated changes in the microstructure and mechanical properties were examined. It was observed that aging resulted in formation of Laves phase causing a decrease in toughness. The creep damage in base metal could be correlated with decrease in hardness, while creep damage in weldments could be correlated with the area fraction and density of creep voids. Creep rupture in weldments occurred in the fine-grained heat affected zone by the formation and growth of creep voids. The fatigue damage in base metal correlated to the maximum length of a crack among micro-cracks initiated during fatigue cycles.     

Transmission capacity of longitudinal power systems and SVC voltage control

Power transfer between systems is important due to uneven distribution of generating plants. This paper investigates the relation between the transfer capacity of a longitudinal power system and voltage control of static var compensators. The transfer capacity is basically limited by the thermal capacity of transmission lines. However, the practical systems, it is much restricted by stability and the power transfer level is considerably lower than the thermal capacity. In this paper, we consider a basic case in which SVCs are applied to all buses except generator terminals. In this case, it is possible to transfer power up to the reciprocal of the transmission reactance. Two modifications are then applied to the basic case. One is removal of SVCs on the high-voltage sides of the generator transformers. In this case, generator damping torques deteriorate, and the local oscillation mode becomes unstable. The other is removal of SVCs at intermediate buses on the trunk system. In this case, the shapes of the oscillation modes change greatly, and the global mode becomes unstable. The voltage control of SVCs maintains the generator damping torques and prevents deformation of mode shapes. By investigating different system sizes and transmission circuits, we show that the system transfer capacity is determined by the capacities of the individual transmission lines. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(3): 49–60, 1997     

Fast acquisition system for digital holograms and image processing for three-dimensional display with data manipulation

A three-dimensional (3D) digital holographic display system with image processing is presented. By use of phase-shifting digital holography, we obtain the complex amplitude of a 3D object at a recording plane. Image processing techniques are introduced to improve the quality of the reconstructed 3D object or manipulate 3D objects for elimination and addition of information by modifying the complex amplitude. The results show that the information processing is effective in such manipulations of 3D objects. We also show a fast recording system of 3D objects based on phase-shifting digital holography for display with image processing. The acquisition of 3D object information at 500 Hz is demonstrated experimentally.