Development of Polymethylmethacrylate Based Composite for Gas Sensing Application

Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring and process control. Conductive polymer composites have various industrial applications. The composite prepared by mixing carbon black with polymethylmethacrylate (PMMA) has very good gas sensing applications. The gas sensors based on carbon nanotube/polymer, ceramic and metal oxide composites such as epoxy, polyimide, PMMA / Barium titanate and tin oxide have also been developed. In the present work, a new composite has been prepared by using PMMA and ammonium dihydrogen phosphate (ADP). The PMMA/Ammonium dihydrogen phosphate (PMADP) composites PMADP 1 and PMADP 2 were characterized by using Powder XRD. The thick films of the composite on glass plates were prepared by using a spin coating unit at 9000 rpm. The application of the thick film as gas sensor has been studied between 0 and 2000 seconds. The results reveal that the thick film of PMADP composite can function as a very good gas sensor

COMPARISON OF PUSH-PULL AND NON-ISOLATED HIGH STEP – DOWN DC TO DC CONVERTERS

<p>This paper deals with comparison of Non-isolated buck converter and push- pull converter. Here 48V DC is converted into high frequency AC and it is stepped down to 12V level. The push-pull converter has advantages like reduced switching losses, stresses and EMI. The power output of push-pull converter seems to be of high value compared to the non-isolated buck converter. The simulation results of Non-isolated converter and Push-Pull converter are compared.</p

ORIENTAL JOURNAL OF CHEMISTRY Sensing of Acetone Vapours using Polymer Composite

AbSTRACT People may develop a headache, fatigue and even narcosis when the concentration of acetone in air is higher than 10,000 ppm. Hence, detecting and measuring acetone concentrations in the workplace or human body are necessary for our safety and health. Gas sensors play vital role in detecting, monitoring and controlling the presence of hazardous and poisonous gases in the atmosphere at very low concentrations. In the present work, a thick film of composite was prepared by using PMMA and TiO 2 (PMTi). Then, the composite&apos;s gas sensing behaviour for acetone vapour was tested by measuring the resistance change of the composite at room temperature. An increase in resistance has been observed with a response time of about ten seconds. The PMMA/ TiO 2 (PMTi) composites were characterized by using PXRD, FTIR and SEM. The results show that the thick film of PMTi composite can function as a very good gas sensor for acetone vapours