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    Article

    Development and testing of a surface roughness measurement device based on aerial ultrasonic reflections

    Repairs of concrete irrigation channels in Japan are guided to a large extent by the degree to which their walls have degraded over decades of use. Current methods of estimating Manning roughness coefficients ...

    Kenji Okajima, Seiya Nagaoka, Mohammad Raihanul Islam… in Paddy and Water Environment (2020)

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    Article

    Development of a measurement method for abrasion irrigation channel using underwater ultrasonic wave

    Japan has many concrete irrigation channels with total length of about 400,000 km. Most of these channels are now too old for continued use. It would be too costly to reconstruct these channels. The concrete s...

    Seiya Nagaoka, Kenji Okajima, Ryoei Ito, Ken Watanabe… in Paddy and Water Environment (2019)