Identification of Optimum Operational Parameter Levels for Plain Basin, Corrugated Basin and Compartmental Basin Solar Stills

This study aimed at optimizing or maximizing the distillate production in plain basin, corrugated basin and compartmental basin solar stills by integrating them with optimum level of the four operational parameters - Mass of Heat Storage Material, Basin Water Depth, Basin Cover Thickness and External Mirror Position. The efficiency of the parameters is not uniform and it differs from still to still due to variation in the structure of the basin. Further, the most efficient level in a parameter differs from still to still. A particular basin water depth which is highly productive in plain basin still may not suit well for corrugated or compartmental basin still. To find out the optimum parameter levels, the 4 operational parameters and the four levels of each parameter were combined as per L16 orthogonal array and the distillate production under different combination of operational parameter levels were analyzed using S/N ratio analysis, mean response method, analysis of variance and regression analysis. The analysis revealed that the optimum mass of heat storage material was 16 kg in plain basin, 12 kg in corrugated basin and 10 kg in compartmental basin still. The efficiency of corrugated basin and compartmental basin solar stills was maximum at a lower basin water depth of 15 mm and 10 mm respectively. But plain basin still efficiency was maximum at a higher basin water depth of 20 mm. The optimum basin cover thickness was 4 mm in all the solar stills, in spite of a difference in the structure of the basin. In the same way, the distillate production was maximum when the external mirrors were positioned on the two sloping sides of the solar still (east and west direction). The expected production from the solar stills integrated with the optimum parameter levels was estimated using regression analysis and mean response method. The average distillate production which was 3304, 3493 and 3629 ml/m2.day in the modified (not with optimum parameter levels) plain basin, corrugated basin and compartmental basin solar stills respectively, improved to 6414, 7153 and 7629 ml/m2.day respectively when they were modified with optimum parameter levels and the increase in production was 94 %, 105 % and 110 % respectively.

Experimental Investigation on Laser Transmission Welding of Polycarbonate and Acrylic

This chapter presents the effect of various process parameters, namely laser power, pulse frequency, and welding speed, on the weld shear strength and weld width using a diode laser system. Here, laser transmission welding of transparent polycarbonate and black carbon filled acrylic each of 2.8 mm thickness have been performed to create lap joint by using low power laser. Response surface methodology is applied to develop the mathematical model between the laser welding process parameters and the responses of weld joint. The developed mathematical model is tested for its adequacy using analysis of variance and other adequacy measures. It has been observed that laser power and welding speed are the dominant factor followed by frequency. A confirmation test has also been conducted to validate the experimental results at optimum parameter setting. Results show that weld strength of 34.3173 N/mm and weld width of 2.61547 mm have been achieved at optimum parameter setting using desirability function-based optimization technique.

DESIGN AND EXPERIMENTAL OPTIMIZATION OF AIRFOIL-TRIANGLE SIEVE FOR HAMMER MILL

The performance of a hammer mill is affected by the formation of a circulation layer. In this paper, an airfoil-triangle sieve was designed to destroy the circulation layer and improve the performance of the hammer mill. To determine the optimal design parameters of the airfoil-triangle sieve, three-factor and three-level tests were carried out by using the productivity and output per kW•h as the evaluation indexes and the airfoil camber, angle of attack and isosceles angle as the influencing factors. The order of the influences on the productivity was airfoil camber>angle of attack>isosceles angle. The order of the influences on the output per kW•h was angle of attack>airfoil camber>isosceles angle. The optimum combination after parameter optimization was determined to be as follows: airfoil camber of 0.15, angle of attack of 10° and isosceles angle of 113°. A test was carried out with to the optimum parameter combination. The results showed that the productivity and output per kW•h were 1101.56 kg/h and 188.97 kg/kW•h, respectively, which were consistent with the predicted results. The regression model was reliable.