Kishio Arita

Nondestructive Inspection of a Wooden Pole Using Ultrasonic Computed Tomography

Ultrasonic computed tomography is discussed as a means of accomplishing the nondestructive inspection of wooden poles. With this tomography, propagation time of ultrasound is used in a wooden pole as the measured data for the computed tomographic reconstruction because of its measurement ease, unlike the conventional technique. As a result, it has been found that ultrasonic computed tomographic imagings of a wooden pole can be done easily by the method proposed herein and are sufficient for the nondestructive inspection of such poles. Therefore it is concluded that the proposed method will become generally used for such inspection applications.

Corrosion resistant composite layer on magnesium-alloy

A new surface treatment has been developed for Mg-alloys that combines anodizing with thermosetting resin film formation to improve corrosion resistance and electrical insulation. This surface treatment can be followed by metal ion plating to produce superior surface conductivity. This treatment should find extensive applications for Mg-products used in aerospace, electronics and other fields where products must be light and have a high damping capacity.

Electrical Resistivity of Internally Oxidized Cu–Al Alloys

The electrical resistivities at room temperature have been investigated precisely after partial and complete internal oxidation. The internal oxidation rates obtained through electrical resistivity measurements are always smaller than the real rates which are obtained metallo-graphically. This suggests that the resistivities of subscales after partial internal oxidation are greater than those after complete internal oxidation, and that it is wrong to estimate internal oxidation rates through resistivity measurements. After complete internal oxidation, deviations from Matthiessens rule (DMR) are observed in the internally oxidized Cu–Al alloys. The DMRs at 20°C have the same magnitudes as those of the residual resistivities and are nearly proportional to the volume fraction of dispersed Al2O3 particles. The DMR at 20°C in the Cu–1.0 vol%Al2O3, alloy is 0.037 µΩ-cm. The origin of the DMR is attributed to dispersed oxide particles.

Non-Destructive Inspection of Rotted or Termite-Damaged Wooden Poles by Ultrasound

The purpose of this paper is to develop a method for non-destructive inspection of a wooden pole. Two methods are investigated: one uses the propagation characteristics of ultrasound peculiar to a rotted wooden pole, and the otter uses the technique of ultrasonic computed tomography. The former method has a special merit in its simplicity and the latter is expected to become a method for general use.