Preparation and Characterization of Active SiO2 from Cymbopogon citratus Ash Calcined at Different Temperature

Cymbopogon citratus or lemon grass, is a potential renewable herbaceous biomass alternative. Lemon grass contains silica, which is available for extraction as a filler for various applications. Lemon grass ash is produced at calcination temperatures of 0, 400, 525, 600, and 700 ˚C. The silica content of the lemon grass ash was characterized by X-ray fluorescence (XRF), X-ray powder diffraction (XRD), scanning electron microcopy (SEM), and Fourier transform infrared (FTIR) analysis. The shape and texture of the lemon grass ash were studied by SEM. The highest silica content recorded was 24.00% for lemon grass calcined at 400 °C. The porosity of the lemon grass ash increased as the calcination temperature increased from 0 °C to 700 °C. XRD analysis showed that the crystallinity of silica in the lemon grass ash increased with increasing calcination temperature. FTIR analysis confirmed the presence of organic structure in lemon grass without calcination and the inorganic structure of siloxane and silanol bonds present in lemon grass calcined at different temperatures

Warpage Optimisation Using Recycled Polycar-bonates (PC) on Front Panel Housing

Many studies have been done using recycled waste materials to minimise environmental problems. It is a great opportunity to explore mechanical recycling and the use of recycled and virgin blend as a material to produce new products with minimum defects. In this study, appropriate processing parameters were considered to mould the front panel housing part using R0% (virgin), R30% (30% virgin: 70% recycled), R40% (40% virgin: 60% recycled) and R50% (50% virgin: 50% recycled) of Polycarbonate (PC). The manufacturing ability and quality during preliminary stage can be predicted through simulation analysis using Autodesk Moldflow Insight 2012 software. The recommended processing parameters and values of warpage in x and y directions can also be obtained using this software. No value of warpage was obtained from simulation studies for x direction on the front panel housing. Therefore, this study only focused on reducing the warpage in the y direction. Response Surface Methodology (RSM) and Genetic Algorithm (GA) optimisation methods were used to find the optimal processing parameters. As the results, the optimal ratio of recycled PC material was found to be R30%, followed by R40% and R50% materials using RSM and GA methods as compared to the average value of warpage on the moulded part using R0%. The most influential processing parameter that contributed to warpage defect was packing pressure for all materials used in this study