Optimization of Electro Discharge Machining Parameters on Mg / SiC P-Metal Matrix Composites by Response Surface Methodology
Metal Matrix Composites (MMCs) are present engineer ing materials which have more advantages when compare to conventional materials. Magnesium based MMCs among the MMCs have become an important resear ch subject because of their low density and high stren gth/weight ratio in recent years. The aim of this s tudy is to find out the most influence factors of the electro-disch arge machining (EDM) process parameters. The specim ens were used as Mg/SiCp metal matrix composites. The specim ens were prepared by the powder metallurgy techniqu es. Brass tool with diameter of 10mm was used to machin e the specimens. Experiments were conducted under d iff rent conditions of pulse on time (Ton), pulse off time ( Toff), current (I). The output responses measured w re material removal rate (MRR) and Tool wear rate (TWR). Mathem atical models are proposed for the above responses using response surface methodology (RSM). The analysis of variance (ANOVA) was carried out to study the effe ct of process parameters on process performance.
ESTABLISHING EMPIRICAL RELATION TO PREDICT TEMPERATURE DIFFERENCE OF VORTEX TUBE USING RESPONSE SURFACE METHODOLOGY
Vortex tube is a device that produces cold and hot air simultaneously from the source of compressed air. In this work an attempt has been made to investigate the effect of three controllable input variables namely diameter of the orifices, diameter of the nozzles and inlet pressure over the temperature difference in the cold side as output using Response Surface Methodology (RSM). Experiments are conducted using central composite design with three factors at three levels. The influence of vital parameters and interaction among these are investigated using analysis of variance (ANOVA). The proposed mathematical model in this study has proven to fit and in line with experimental values with a 95% confidence interval. It is found that the inlet pressure and diameter of nozzle are significant factors that affect the performance of vortex tube.
Preparation of hydrophilic poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation
Abstract Hydrophilic microporous hollow fiber membranes were prepared via thermally induced phase separation (TIPS). Poly(vinyl butyral) (PVB) and three kinds of polyethylene glycols (PEG) with the molecular weight of 200, 400 and 600 were used as polymer and diluents. In all cases, liquid–liquid (L–L) phase separation occurred and asymmetric cellular structures with the smaller pores at the outer surface were obtained. The properties of membranes such as pore size, water permeability, solute rejection and intensity were investigated by changing molecular weight of PEG, concentration of PVB, composition of the bath and air gap distance. The smaller molecular weight of PEG, the more PEG in the bath and the shorter air gap distance resulted in the higher water permeability, the lower solute rejection property and the lower mechanical strength.