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Water is often present in fuel tanks due to night and day temperature changes, resulting in a build-up of condensed water within the inner surface of the tank. The expectancy of water infiltration in fuel tanks is even higher in flooding prone areas. Water settlement at the bottom of the tank causes internal corrosion. In this work, a simple, low cost and accurate microwave reflection type system for detection of water in fuel tanks has been developed. A module consisting of a microwave generator and a detecting diode is used to measure the microwave reflection coefficient at various positions through the fuel tank. In the course of the study, a motion control and data acquisition system has been developed. Software written using the LabVIEW programming language is used to control the movement of the sensor and for the data acquisition. Theoretical and experimental results show the ability of the system to detect the presence of a water level down to approximately 1 mm. A simple theoretical model for power prediction of the reflected signal at various positions of the sensor in the tank is also presented.

Temperature variation causes errors in all indirect moisture measurement methods. To increase the accuracy of moisture content determination and to reduce the influence of temperature, a two-parameter measurement is used. The method uses the magnitude of reflected waves at two microwave frequencies in the X-band region. A dual frequency sensor system is developed to measure moisture content of dielectric-lossy liquids. The experiment is based on measurements of far-field reflection magnitudes at two different frequencies 8.48 GHz and 10.69 GHz using circular microstrip antennas. A calibration equation is sought that instantly gives temperature-independent moisture content of the samples under consideration. The sensor is integrated with a data acquisition card to record the detected reflection signals. The data analysis and error-correction technique are implemented using custom designed software. The system is tested using diluted rubber latex with moisture content ranging from 39.8% to 91.2% wet basis. The moisture content was predicted with a standard error less than 1.3% for the temperature range of 25 °C to 63 °C compared to the standard oven-drying technique

The suitability of a single-access approach involving a pulsed laser technique for non-contact and non-destructive measurement of thermal diffusivity is further examined. It was used to measure the thermal diffusivity of black and metallic graphite paint coatings. The values obtained in the present work are and for black and metallic graphite paint coatings respectively. All measurements were performed at room temperature.