Abstract This paper describes a new crack tip diffraction approach using a set of angle beam and direct contact transducers. In this approach, a crack height is calculated from a time di fference from two echoes of a tip-diffracted longitudinal wave, which arise after an incident wave from the angle beam transducer impinges the crack. The two echoes are detected by the d irect contact transducer which lies on the opposite surface of and over the crack. One echo is related to the wave traveling directly fro...
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Proposal of Concise Crack Sizing Approach in Ultrasonics

Atom probe tomography (APT) has been performed on Fe-1.4Mn0.6Ni (at%) model alloy to study solute elements behavior under 2.8 MeV Fe ions at 400 0C. Orientation imaging microscopy (OIM) analysis is applied on the detector hit map to determine the pole figure supporting for orientation calculation. The three-dimensional images show that Mn and Ni solute atoms are distributed close to some certain planes, namely <111> and <100> families. This arrangement of solute atoms on the habit planes of interstitial loo...
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Anisotropic distribution of solute elements in ion － irradiated reactor pressure vessel model alloy

The authors have already proposed microwave nondestructive testing (NDT) method on detecting both location and degree of a pipe wall thinning (PWT) inside a metal pipe. However, problems caused by iofouling inside metal pipes are also frequ ently reported in recent years. As the existence of biofilm inside a aveguide will change its wave impedance and also cause microwave reflections, the characteristic signals of iofilm defects are studied here to distinguish the biofilm and PWT defects. A pair of coaxial...
英字タイトル:
Application of Microwaves on Remote and Nondestructive Testing of both Biofouling and Wall Thinning inside a Metal Pipe

Respiratory motion can induce the limit in the accuracy of area irradiated during lung cancer radiation therapy. Many methods have been introduced to minimize the impact of healthy tissue irradiation due to the lung tumor mot ion. The purpose of this research is to develop an algorithm for the improvement of image guided radiation therapy by the prediction of motion images. We predict the motion images by using principal component analysis (PCA) a nd multi-channel singular spectral analysis (MSSA) method. ...
英字タイトル:
Development of motion image prediction method using principal componentanalysis

本研究では、PWRプラント運転を想定した熱時効初期の残留応力緩和メカニズム解明の一環として、LP、WJP、バフ研磨の三工法および機械加工を施した600合金について、熱時効時の組織変化を明確にすることを目的とした。各工法の施工材についてEBSD解析を行うことにより、応力緩和過程に関与すると考えられる組織学的因子の検討を実施した。...
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Microstructural Investigation of Residual Stress Relaxation Process of Ni-based Alloy by EBSD Analysis

The present study discusses electromagnetic characteristics of modeling thermal fatigue crack in numerical simulation from view point of eddy current testing. Two thermal fatigue cracks introduced into SUS304 stainless steel plates are investigated. Eddy current signals are gathered by a differential plus point probe with several frequencies, 50 kHz, 100 kHz and 400 kHz. In the numerical simulation thermal fatigue crack is modeled as a region with constant width, true profile revealed by results of destruc...
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Investigation on electromagnetic characteristics numerical simulation by eddy current testing

This paper evaluated the probability of detection(POD) of austenitic stainless steel welds from the viewpoint of ultrasonic testing. It presents results of simulation-based POD curves of ultrasonic NDT. The simulation model based on a three-dimensional Finite Element Method (FEM) is presented to perform the data generation. Results of conventional POD considering the depth of flaw are given and the requirement of taking the length of flaw into considered is determined....
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Probability of detection analysis of ultrasonic NDT applied to austenitic stainless steel welds

Image guided radiation therapy (IGRT) has played a major role in the precision of radiation therapy especially while tracking moving tumors. The IGRT units are capable of 2D planar imaging, fluoroscopy etc. As lung tumor tends to move and deform during respiration, it also undergoes a sudden phase change in motion due to sudden cough or sneezing during the treatment which leads to the treatment beam missing the target. In this study we propose an algorithm for tracking moving tumors during radiation t...
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Sudden change detection in moving tumors for dynamic tracking in lung cancer radiation therapy

Suppressing the stress corrosion cracking by reducing carbon contents in austenitic stainless steels seems to be not effective on core shrouds used in boiling water reactor in Japan. Trans-granul ar cracking was found out in the shrouds. To clarify a mechanism of the cracking, stress measurement on specimens under stretched condition in hot water has been attempted in the present study. A n in-situ device for diffraction measurements in synchrotron radiation facility has been developed by the present autho...
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Effect of Surface Grinding on Residual Stress in Low Carbon Austenitic Stainless Steel SUS316L

In order to prevent primary water stress corrosion cracking (PWSCC), water jet peening (WJP) has been used on the welds of Ni-based alloys in pressurized water reactors (PWRs). However, the compressive residual stresses induced by WJP might be relaxed during the actual operation because of the elevated temperature environment. Therefore, the stability of the compressive residual stresses caused by WJP has been investigated during thermal aging. The result shows that the compressive residual stresses has...
英字タイトル:
Relaxation behavior of residual stress generated by water jet peening under operation temperature environment ― Evaluation for long term stability of residual stress improving treatment on Ni base alloy (report 1) ―