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Among many machining operations, drilling has become one of the important machining operations performed in polymer composites. The quality of the drilled hole is closely associated with the drilling parameters and conditions. The current work focuses on the optimization of multiple response characteristics during drilling of hybrid glass fiber reinforced polymeric nanocomposites. Taguchi's L25, orthogonal array is used to conduct the experiments and for optimization of the process parameters. The machining parameters such as spindle speed, feed rate, and drill diameter are optimized for the response which includes delamination, thrust force and torque via grey relational analysis technique. From the grey relational grade analysis, it is clear that the drill diameter is the most influencing factor followed by the feed rate and the spindle speed. The optimized process parameter settings were found as spindle speed of 2700 rpm, the feed rate of 30 mm/ min and drill diameter of 4 mm, respectively, for lower delamination, torque and thrust force. Among the various modeling techniques used, ANN is found to be suitable for the process with minimum error percentage of 0.526.

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Abstract-The paper presents, analyzes and comments on the findings for different type of nano-additives used in painted coatings against the corrosion behavior for steel pipe lines, used in petroleum industry of Oman. The examination for the rate of corrosion in low alloy steel pipelines included a range of coated samples that includes organic paint, metallic paint, Aluminum, Zinc and electroless ones. After the samples were coated, the surface roughness was checked and the coating thickness maintained.

Electroless nickel boron coatings were prepared from thallium and lead-free alkaline bath. The influence of surfactants on the properties of electroless nickel boron coatings was studied. Three surfactants namely sodium dodecyl sulfate, cetyltrimethyl ammonium bromide and 3-(N, N-Dimethylmyristylammonio) propanesulfonate were used. Morphology, microhardness, surface finish, topography and corrosion resistance of the coatings were evaluated. Electroless nickel boron coatings with addition of surfactant sodium dodecyl sulfate, cetyltrimethyl ammonium bromide and 3-(N, N-Dimethylmyristylammonio) propanesulfonate results in a smooth surface, with an average roughness value (R a) of 0.220 mm for cetyltrimethyl ammonium bromide, 0.198 mm for sodium dodecyl sulfate and 0.174 mm for 3-(N, N-Dimethylmyristylammonio) propanesulfonate which are less than the R a without surfactant addition (0.256 mm). The deposits had a microhardness value of 590 and 743 HV in the as-plated and heat-treated conditions, respectively. With addition of sodium dodecyl sulfate, cetyltrimethyl ammonium bromide and 3-(N, N-Dimethylmyristylammonio) propanesulfonate, a significant improvement in the microhardness is observed. Potentiodynamic polarization tests were carried out in 3.5 wt% NaCl to determine the real anticorrosion performance of the electroless nickel boron deposits. The entire experimental procedure, the results achieved, and their investigation are presented in this paper.

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