Journal of Advanced Materials in Engineering (Esteghlal)

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Process optimization is one of the most important activities in today's competitive industries. the rather high cost of research and development has necessitated the development of experimental methods by which the factors affecting processes could be determined with minimum number of experiments. Over the last two decades, various types of experimental designs have been used. Among the different methods of experimental design such as complete and partial factorial and Latin squares design, the Taguchi method has found wide applications in some industrial divisions because of its comprehensive nature. In this paper, the laboratory scale flotation of the Sarcheshmeh copper ore which mainly consists of chalcocite was studied using the Taguchi method. The effects of seven factors namely collectors, Z11 (Xanthate) and R407 (Methyl isoboutyl carbonyl), frothers, pine oil and A65 (Polypropylene glycol), particle size, pH and flotation time were investigated. In addition to a significant reduction in cost and time of experimentation, the results indicated that a 5% increase in copper recovery could be obtained if all the factors are tested at their high experimental levels, as suggested by the Taguchi method. The optimal flotation time was also found to be 11 minutes.

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Reductive leaching was used to dissolve metals, especially cobalt, present in Fars Tidar mine,. In this paper, cobalt ore was leached with sulphuric acid in the presence of phenol to determine the effects of various factors on leaching. These factors included temperature, acid concentration, time, phenol content, pulp density, and interaction between some of the parameters. The results indicated that temperature was more effective on SN ratio (Signal to Noise ratio) which was found to be about 80%. The effecst of time and acid concentration on SN ratio were also determined at about 8% and 4 %, respectively. Although the effect of phenol content on cobalt leaching was too low but dissolution of cobalt decreased in the absence of phenol. Therefore, it was concluded that phenol was one of the factors in effective the leaching process. Anyway, three parameters including temperature, acid concentration, and time were selected as more effective parameters. Consequently optimum conditions can be obtained with high levels content of temperature, acid concentration, and time with low levels of phenol and pulp density.

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In this study, the parameters affecting the synthesis of silver nanoparticles were optimized by green chemical reduction method to make a conductive pattern. The raw materials used in this study, include silver nitrate as a source of
silver ions, polyvinylpyrrolidone as surface stabilizer, and glucose as the reducing agent. Effective parameters were investigated
by Taguchi statistical design, to determine the optimum conditions and achieve the smallest average particle size. Silver nanoparticles were characterized by X-ray diffraction and field emission scanning electron microscopy. The smallest particle size can be applied by solution adding rate of 0.1 ml/min, temperature 90 ^°C, weight ratio of glucose to silver nitrate 3 g/g and weight ratio of Polyvinylpyrrolidone to silver nitrate 3.2 g/g. According to.our expectation 20 nm silver nanoparticles were obtained in this condition. FE-SEM confirmed the above results and showed nanoparticles with a size of 25 nm. Finally, A conductive pattern was printed on a glass substrate with synthesized powder. The electrical resistance of the printed pattern was 0.088× 10 ^-4 Ω.cm.

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This research investigated the bonding properties of AISI 321 austenitic stainless steel from microstructural, mechanical, and corrosion points of view. To obtain the optimal parameters of pulsed current gas tungsten arc welding (PCGTAW), the Taguchi method was used. A cyclic potentiodynamic polarization test evaluated the corrosion resistance of the welded samples. The optimal conditions were achieved when the background current, the pulse current, the frequency, and the percentage of the pulse on time were 50 amps, 140 amps, 5 Hz, and 50, respectively. On the other hand, the analysis of variance showed that the percentage of pulse on time equal to 36 and the background current equal to 46 amperes were the most influential factors on the surface current density of the austenitic stainless steel 321 connection using the PCGTAW process. The mechanical properties were assessed using punch shear testing. In the optimal condition, the maximum shear force and strength were 3200 N and 612 MPa, respectively. The results showed that the most critical factor affecting the bonding properties of 321 steel was the heat input.