Development of a multi-component water quality sensor

点击翻译按钮获取中文摘要

Coastal water may contain various substances like turbid matters discharged from adjacent land area and those like phyto-planktons produced internally with ample nutrients. Therefore existing sensors cannot be applied to precise multi-component estimation, because they are based on a principal assumption that there exists only one component concerned in the water. In this study, for overcoming this difficulty, we have attempted to develop a new type sensor, "multi-component water quality sensor" as follows.l) The new sensor is based on the methodology recently developed by Miyazaki ＆ Nadaoka for remotely sensed image analysis. Since it is for 1-D optical transmission and for the present purpose, on the other hand, a 3-D optical path should be considered, four flux model may not be applied. Therefore, in this study, we have developed a simulation model based on a Monte Carlo method for the optical design of the sensor.2) By performing a laboratory experiment, we have confirmed the fundamental validity of the model in terms of spectral attenuation and scattering characteristics.3) Based on this optical simulation model, we have developed an algorithm to inversely estimate the multi-substance concentration.4) We have examined the fundamental design and specifications of the optical assembly unit, memory unit, and power unit. We have paid special attention on the durability and compactness of the sensor for long-term use in the fields under severe conditions.5) Based on these efforts, we have developed a pilot "multi-component water quality sensor", and confirmed its fundamental performance.