Chemical bonded resin sand mould system has high dimensional accuracy, surface finish and sand mould properties compared to green
sand mould system. The mould cavity prepared under chemical bonded sand mould system must produce sufficient permeability and
hardness to withstand sand drop while pouring molten metal through ladle. The demand for improved values of permeability and mould
hardness depends on systematic study and analysis of influencing variables namely grain fineness number, setting time, percent of resin
and hardener. Try-error experiment methods and analysis were considered impractical in actual foundry practice due to the associated cost.
Experimental matrices of central composite design allow conducting minimum experiments that provide complete insight of the process.
Statistical significance of influencing variables and their interaction were determined to control the process. Analysis of variance
(ANOVA) test was conducted to validate the model statistically. Mathematical equation was derived separately for mould hardness and
permeability, which are expressed as a non-linear function of input variables based on the collected experimental input-output data. The
developed model prediction accuracy for practical usefulness was tested with 10 random experimental conditions. The decision variables
for higher mould hardness and permeability were determined using desirability function approach. The prediction results were found to be
consistent with experimental values.
The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test
rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex
stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment
was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent
parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical
significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the
behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test.
Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further,
the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters
responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface
characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was
obtained for the determined optimal condition by desirability function approach.
A novel methodology was implemented in the present study to concurrently control power conversion efficiency (η) and durability (D) of co-sensitized dye solar cells. Applying response surface methodology (RSM) and Desirability Function (DF), the main influential assembling (dye volume ratio and anti-aggregation agent concentration) and operational (performance temperature) parameters were systematically changed to probe their main and interactive effects on the η and D responses. Individual optimization based on RSM elucidated that D can be solely controlled by changing the ratio of vat-based organic photosensitizers, whereas η takes both effects of dye volume ratio and anti-aggregation concentration into account. Among the studied factors, the performance temperature played the most vital role in η and D regulation. In particular, however, multi-objective optimization by DF explored the degree to which one should be careful about manipulation of assembling and operational parameters in the way maximization of performance of a co-sensitized dye solar cell.