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In Japan, the total length of the main concrete agriculture irrigation canals is estimated to beabout 50,000 km. These canals deteriorate over time and most of the canal surface has become rough. Onemethod of measurement of the roughness of the concrete surface is by the aerial ultrasonic sensor. As far asthe literature is concerned, no study of the use of 42-kHz sensors for the evaluation of ultrasonic attenuationduring air propagation has been conducted. The aim of this study is to evaluate and correct the attenuated valuesof an ultrasonic wave. In this paper, the reflected wave of the ultrasonic wave was measured under differentconditions of temperature, humidity, and atmospheric pressure with a smooth board and a rough board. Thesewere corrected by using the ISO9613-1 equation. It is concluded that the relative error of the corrected valueis small when compared with the measured value. The results of this study reveal that correction using theISO9613-1 equation for attenuation of the 42-kHz ultrasonic wave is an effective method.
Nagaoka Seiya (Fri,) studied this question.