• Energy Research

A range of optical fibre-based sensors for the measurement of ethanol, primarily in aqueous solution, have been developed and are reviewed here. The sensing approaches can be classified into four groups according to the measurement techniques used, namely absorption (or absorbance), external interferometric, internal fibre grating and plasmonic sensing. The sensors within these groupings can be compared in terms of their characteristic performance indicators, which include sensitivity, resolution and measurement range. Here, particular attention is paid to the potential application areas of these sensors as ethanol production is globally viewed as an important industrial activity. Potential industrial applications are highlighted in the context of the emergence of the internet of things (IoT), which is driving widespread utilization of these sensors in the commercially significant industrial and medical sectors. The review concludes with a summary of the current status and future prospects of optical fibre ethanol sensors for industrial use.

Abstract A fibre-optic sensor for the monitoring of hazardous exhaust gases is described. The sensor based on ultraviolet (UV) differential optical absorption spectroscopy (DOAS) was developed for the simultaneous monitoring of several exhaust gases from passenger cars. Experimental results describing the operation of this sensor with calibrated cylinder gases as well as in a full-size engine are presented. The sensor has been developed to operate within an exhaust environment and have low susceptibility to interferences from other gases present. The lower limit of detection for the sensor was found to be 5 ppm for nitric oxide (NO), 1 ppm for both nitrogen dioxide (NO2) and sulphur dioxide (SO2) and response time was found to be 3.4 s.