Tin oxide sensors for insect infestation detection
Type of Degreethesis
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Agriculture suffers a significant loss every year due to pests. Early detection of insect infestation is important to reduce that kind of loss. Plants emit volatile organic compounds whose composition will change after the infestation of pests. Detection of such change can provide the critical information for pest control. In this research thick film hotplate type tin oxide sensors are used to detect Methyl Jasmonate, an important plants’ defense relating volatile chemical. The tests are performed by a gas flowing system. For the concentration dependence study of the sensors different partial flow rate (0.02L/min, 0.04L/min, 0.06L/min, 0.08L/min, 0.10L/min, 0.12L/min, 0.16L/min, 0.20L/min) of Methyl Jasmonate at 25°C in dry air flow is tested. Gas chromatography is used to determine the exact concentration of Methyl Jasmonate at different partial flow rate. The sensors’ relative sensitivity is found to be from 2 to 5 and follow the power law relationship with the concentration of Methyl Jasmonate. For the temperature dependence study of the sensors the tests are performed in dry air flow at different temperature (-22°C, -12°C, -2°C, 7°C, 17°C, 22°C, 27°C, 32°C, 37°C). The sensor’s relative sensitivity is found to be relatively low about 4 around 20°C and increases with decreasing ambient temperature below 10°C. For humidity dependence study the tests are performed at 25°C with different relative humidity (20%, 64%, 70%, 82%, 94%). The relative sensitivity of the sensor is decreasing with increasing relative humidity, but still above 3 in high relative humidity. According to the performance of the sensors to different concentration of Methyl Jasmonate at different temperature and relative humidity the capability of tin oxide sensors in detecting insect infestation is discussed.