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Abstract: The 3–11 Earthquake occurred in Japan last year had greatly damaged the lives and properties and also caused the core meltdown accident in the Fukushima nuclear power plant followed by the leakage of radioactive materials into biosphere. In order to protect against the detriment of radiation from foods which were imported from Japan, the Institute of Nuclear Energy Research (INER) in Taiwan started to conduct radioactivity inspection of food products from Japan after the accident. A total of about 20,000 samples had been tested from March 24 2011 to March 31 2012. [Copyright &y& Elsevier]

• The evolutionary process of pipe jacking method in Japan was reviewd. • The classification system provided by the Japan Microtunneling Association was introduced. • The application status of this method is investigated based on survey data from JSTT. • SPJ and HDSPJ have better performance for the ultra-long pipe jacking construction. • Curved pipe jacking projects account for 40% of total jacking projects, and HDSPJ is most adopted for curved pipe jacking. Pipe-jacking is one of the trenchless methods being widely used for the construction and maintenance of urban underground pipelines. As an eco-friendly construction method, it has the capacity for the installation of pipelines with diameters from 100 mm (4 in.) to 5000 mm (200 in.) covering the majority needs of municipal pipeline construction and is considered the most widely used trenchless method in Japan. However, there is little English literature that systematically introduces the research and application status of pipe jacking technology in Japan, resulting in a serious underestimation of Japanese research achievements in this field. This paper briefly reviews the origin, evolutionary stages, and classification system of the pipe jacking method in Japan, and representative technological advances are also introduced through case statistics. Meanwhile, the deficiencies in the current classification system of the International Society of Trenchless Technology (ISTT) are discussed as well. In addition, the application status of this method is investigated based on survey data from the Japan Society for Trenchless Technology (JSTT). According to the survey data from 5232 projects, a systematic analysis is carried out on the selection of pipe jacking equipment, the scale of jacking construction, the profile of curved projects, and the geological adaptability of the pipe jacking method in Japan. The emphasis of this paper is to introduce the current technical situation and analyze the development trends of the pipe-jacking method based on Japan's experience, and to popularize this method in other countries that need this simple, effective, and economical construction technique under the background of climate change. [ABSTRACT FROM AUTHOR]

Observations of ocean currents are important information in the fields of ocean science and engineering. Reciprocal acoustic transmissions have the potential to operationally measure tidal currents in coastal seas. This study investigates the capability of the reciprocal transmissions to measure tidal currents, particularly in relation to high-frequency variations. We conducted a reciprocal acoustic transmission experiment in an area of complex coastlines in the Seto Inland Sea, Japan, in October 2019. During this experiment, a burst transmission was used, and the system performed six transmissions with 1-min intervals between them every 10 min. The estimated path-averaged currents agreed with the currents obtained from a shipboard acoustic Doppler current profiler (ADCP) on an hourly basis and had captured high-frequency variations that were not captured by the hourly ADCP observations. The measurement noise of the estimated currents, which was determined as the variation within the six transmissions, was 2.5 cm s−1 and was small enough to trace the variations in the currents over the time series even for the variations with periods considerably shorter than M2 tide. The reciprocal transmission's capability to capture high-frequency variations will improve the capability to reproduce current velocity fields when inversion or data assimilation methods are applied. • We conducted a reciprocal acoustic transmission experiment with burst transmission. • Observed path-averaged currents agreed with ADCP; RMS difference is about 10 cm/s. • Measurement noise was estimated at 2.5 cm/s as the variations over a short period. • Observed currents had high SNR; the variations can be traced over the time series. [ABSTRACT FROM AUTHOR]