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This work contributes two novel modified Taguchi techniques to the optimal parametric setting for minimum water absorption in epoxy composites. Taguchi method, using ASTM standards was applied with factors (initial weight, final weight, length, sample thickness and time of immersion) and four levels in the experimental design. The analysis of variance (ANOVA) evaluates the significance and individual contributions of the parameters. The optimal parametric setting was A1B4C3D4E1 (initial weight, 2.61 g; final weight, 2.69 g; length, 62.73 mm; thickness, 3.88 mm; time, 15.65 hrs). The ANOVA identifies time and length as dominant parameters (98.98 and 1.02 % contributions, respectively). Taguchi-Pareto analysis found only factor-level from the time and length parameters economical to optimality. The Taguchi-ABC analysis revealed the individual weights and contributions of the factor-level irrespective of its initial groupings. The new Taguchi techniques highlighted the importance of time and length of sample in obtaining minimum water absorption of composites.

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Ceramic matrix composites reinforced with metals have been developed to overcome the intensive brittleness and lack of reliability of monolithic ceramics, with a view to introduce ceramics in structural parts used in severe environments such as rocket and jet engines, gas turbines for power plants, heat shields for space vehicles, fusion reactor first wall, aircraft brakes, heat treatment furnaces. In view of these the effects of Al-6%Si alloy particles on the ascast microstructure and properties of Tin Tailings ceramics matrix composites produced by powder metallurgy method have been studied. 5-30 weight percent Al-6%Si alloy particles were added. The results revealed that, addition of Al-6%Si alloy reinforcement increased the linear shrinkage, strength and impact energy with a decreased in density, porosity and hardness value. These increases in strength and impact energy are attributed to the uniform distribution and strong bonding of the soft metal phase in the hard ceramic matrix. These results show that better properties are achievable by addition of Al-6%Si alloy to Tin Tailings.

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Physical properties such as apparent density, bulk density, compressibility index and particle sizes of carbonized and uncarbonized coconut shell nanoparticles produced through top down approach have been studied. Percentage composition of the coconut fruit was determined using five different coconut fruit samples. Results revealed that coir occupies the highest percentage; coconut shells account for 15 % while the flesh and liquid occupy 30 % of the whole coconut fruit. The apparent densities of the uncarbonized and carbonized coconut shell nanoparticles obtained at 70 hours of milling are 0.65 g/cm3 and 0.61 g/cm3 respectively. Their respective compressibility indices and average particle sizes are 46.4 % and 69.7 %; 50.01 nm and 14.29 nm. The difference in the particle sizes of the carbonized and uncarbonized coconut shell nanoparticles can be linked with reduction in the moisture content and volatiles of the carbonized coconut shell nanoparticles due to carbonization process. The reduction in the moisture and volatiles results in the enhanced hardness and brittleness of the carbonized coconut shells which facilitate their breakage during the course of milling than that of the uncarbonized coconut shells. Kathmandu University Journal of Science, Engineering and Technology Vol. 12, No. I, June, 2016, Page: 63-79