No abstract

There is found no significant difference between male and female in all the variables. SV-stroke volume, LVMI-left ventricular mass index. ANPatrial natriuretic peptide, BNP-brain natriuretic peptide, Table 2 ANP, BNP, BUN, Cre, echocardiographic parameters and others according to aging Both ANP and BNP were elevated in the older 3 age groups, mild renal dysfunction in the older age groups may partially have contributed in these elevation.

We developed the new method for predicting a region of compressive residual stress on the weld surface after water jet peeing (WJP), which is a preventive maintenance technology for nuclear power plants. A cavitating jet is impinged on the weld surfaces of structures in a nuclear reactor. Bubble collapse impact causes plastic deformation of the weld surface, and changes the residual stress from tensile to compressive. Compressive residual stress prevents the occurrence of stress corrosion cracking (SCC) on the weld surface. A cavitating jet vertically injected into a submerged flat plate was investigated. Tensile stress was introduced onto the surface of the stainless steel plate by grinding before WJP in the experiment. We numerically simulated impulsive bubble pressure that varied by microseconds in the cavitating jet with the “bubble flow model”. The bubble flow model simulates the abrupt time-variations in the radius and inner pressure of bubbles based on the Rayleigh-Plesset equation in a cavitating flow. The cavitation collapse energy was estimated based on the bubble pressure. The cavitation collapse energy was compared with the measured compressive residual stress on the flat plate after WJP. The radial range of the compressive residual stress from the jet center axis is one of the most important measures of performance of WJP. The radial range of the cavitation collapse energy corresponded to that of compressive residual stress with a prediction error of +/− 20% under different conditions of jet velocity and the distance between the jet nozzle and plate surface. The results confirmed that the method we developed for predicting the region of compressive residual stress after WJP was valid.

No abstract

Water Jot P 弸 血 g ( WJP ) is跏 effective techn ゆ e for reducing tensile residual stress and for mitigating stress corroslon cracking ( SCC ) gene 耐 ion on the mate 貞als of nucl 。ar power plants ， Thls paper summarizes the effects of W 亅 P on SCC mitigation and desc 面 es the devdopment of 丘eldapplication technologics to BWR core suppS ) rt structures f ( ) r SCC mi 廿 ga 亘on ．