Sharif Digital Repository

The orthogonal array design has been used to determine the optimum conditions for gold recovery from Zarshuran refractory gold sulflde ore (Iran) by direct cyanidation and roasting-cyanidation. The Taguchi method was used as the experimental design to determine the optimum conditions of dissolution behavior of gold with cyanidation and roasting-cyanidation from Zarshuran refractory gold ore. The experimental conditions were studied in the range of 10-12 for pH, 20-40 for time(h), 400-1200 for cyanide content (g/ton) and 30 -40 for percent solid(%). Orthogonal array (OA) L9 (34) consisting of four parameters each with three levels, was chosen. From this study for direct cyanidation the total... 

A hydrophilic macromolecular network is prepared by performing graft opolymerization of poly (sodium acrylate) chains onto salep and silica gel. The reaction parameters affecting the water absorbency of the superabsorbent composite were optimized using Taguchi method. FT-IR spectroscopy and Thermo Gravimetric Analysis (TGA) were used for confirming the structure of the final product and morphology of the synthesized superabsorbent composite was examined by SEM. The swelling behavior of optimum superabsorbent composite was measured in various swelling media. In addition, swelling kinetics and on-off switching behavior were investigated. In order to evaluate the controlled release potential of... 

A novel biopolymer-based composite hydrogel was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the carboxymethyl cellulose (CMC). The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with five factors and four levels. In the synthesis of the composite superabsorbent, N,N'-methylene bisacrylamide (MBA) as crosslinker, ammonium persulfate (APS) as initiator, acrylic acid (AA) as monomer, CMC/Celite weight ratio and neutralization percent (NU) were used as... 

The present research work is based on finding the optimum conditions for pressure oxidative leaching of the molybdenite concentrate to produce technical-grade molybdic oxide (MoO 3) with high recovery through further treatment of the filtrate solution. The Taguchi method was used to design and minimize the number of experiments. By using Taguchi orthogonal (L 25) array, five parameters (time, temperature, oxygen pressure, pulp density and acid concentration) at five levels were selected for 25 experiments. The experiments were designed and carried out in a high-pressure reactor in the presence of nitric acid as solvent and oxidizing agent for the molybdenite concentrate and its ReS 2... 

The biological oxidation of ferrous ion by iron-oxidizing bacteria is potentially a useful industrial process for removal of H2S from industrial gases, desulphurization of coal, removal of sulfur dioxide from flue gas, treatment of acid mine drainage and regeneration of an oxidant agent in hydrometallurgical leaching operations. The main purpose of this study was to find optimum values of the process parameters on the ferrous biooxidation rate by immobilization of a native Sulfobacillus species on the surface of low density polyethylene (LDPE) particles in a packed-bed bioreactor using Taguchi method. Five control factors, including temperature, initial pH of feed solution, dilution rate,... 

A hybrid algorithm of a particle swarm optimization and a fuzzy rule-based classification system is proposed in this study to diagnose breast cancer. Two orthogonal and triangular types of fuzzy sets are applied to represent the input variables. In additional, different input membership functions are considered to increase the classification accuracy. The performance of the proposed hybrid algorithm is studied using a classification accuracy measure on the Wisconsin breast cancer dataset. The results of the comparison using different training data sets show the higher performance of the proposed methodology  

A novel biopolymer-based hydrogel composite was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the hydrolyzed collagen. The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with five factors and four levels. In the synthesis of the composite superabsorbent, N,N′-methylene bisacrylamide (MBA) as crosslinker, ammonium persulfate (APS) as initiator, acrylic acid (AA) as monomer, neutralization percent (NU), and collagen/kaolin weight ratio were used as... 

Gelatin is a denatured protein derived from collagen by thermohydrolysis and has a rheological property of thermo reversible transformation between sol & gel. Gelatin is one of the most important biopolymers, with widespread applications in the food, pharmaceutical, cosmetic and photographic industries. Gelatin is commercially made from skins and skeletons of bovine and porcine and mammalian gelatin has been intensively studied. However, mammalian gelatin is at risk for contamination with bovine spongiform encephalopathy and increase in demand for kosher and halal foods have created a demand for fish gelatin for food applications. Therefore, the objective of this study was to extract gelatin... 

In this paper, a robust design method is developed for reducing cost and improving quality in aluminium recycling. An experimental investigation into the process parameter effects is presented to determine the optimum configuration of design parameters for performance, quality and cost. The Taguchi method is applied initially to plan a minimum number of experiments. Orthogonal array techniques are used to investigate the simultaneous variation of several parameters and the investigation of interactions between parameters. Matrix experiments using standard L4 and L9 orthogonal arrays are employed to evaluate the effects of parameters in recycling of aluminium dross and scrap materials. A... 

In this paper, a seasonal multi-product multi-period inventory control problem is modeled in which the inventory costs are obtained under inflation and all-unit discount policy. Furthermore, the products are delivered in boxes of known number of items, and in case of shortage, a fraction of demand is considered backorder and a fraction lost sale. Besides, the total storage space and total available budget are limited. The objective is to find the optimal number of boxes of the products in different periods to minimize the total inventory cost (including ordering, holding, shortage, and purchasing costs). Since the integer nonlinear model of the problem is hard to solve using exact methods, a... 

Delamination is a major problem in drilling of fiber-reinforced composite materials. Thrust force is an important factor leading to propagation of delamination during drilling process. One of effective methods to reduce machining forces is application of ultrasonic vibrations. In this study ultrasonic assisted drilling is applied to reduce thrust force in drilling of GFRP laminates. In order to conduct experiments a setup is designed and fabricated to apply both vibrations and rotation to drill bits. Using Taguchi method, a set of experiments is conducted with feed rate, spindle speed, and ultrasonic vibration amplitude as control factors. The results show that applying ultrasonic vibration... 

In this study, some stabilized magnetite based ferrofluids were synthesized using Dextran as a stabilizing agent. In order to achieve optimum experimental conditions for synthesizing ferrofluids as MRI contrast agents, the Taguchi method was used. This approach was employed to design and minimize the number of required experiments. By using the Taguchi orthogonal (L16) array, four parameters including solution temperature and alkalinity, reaction temperature and stirring rate were selected at four predetermined levels for 16 experiments. Synthesizing processes established based on this set of experimental conditions were carried out and the obtained ferrofluids were characterized using PCS,... 

The level and character of noise emitted by exhaust system has significant effect on the overall acoustic performance of vehicle powertrain and sound quality which is received by occupants. In addition to meeting aforementioned objective, the exhaust system must meet exterior noise regulation which is ordered by governments. In this study, acoustic performance of the vehicle exhaust system is investigated. Numerical simulation is applied for this aim that is the fastest and the most economical method in early design stages of vehicle development process. Thickness optimum design is performed in order to improve acoustic performance of exhaust system. Robust parameter design, based on Taguchi... 

In this paper, the effects of different parameters on the hairiness of siro-jet spun yarns, such as the nozzle pressure, the distance between the front roller nip and inlet of the nozzle, and jet structure were investigated. Using the Taguchi method, it was concluded that the factor air pressure has the strongest effect and the factor distance between the front roller nip and inlet of the nozzle does not have a significant effect on the performance of the siro-jet spinning system in reducing yarn hairiness. A computational fluid dynamics model was developed to simulate the airflow pattern inside the jets. The effect of air pressure and the jet structure was simulated using Fluent 6.3... 

In this study, the essential oil of aerial parts species of a plant called Spearmint was extracted by CO 2 to optimize the results of the supercritical extraction process. In order to achieve maximum total yield extraction and SF-CO 2 concentration, tests were done in a laboratorial pilot considering the Taguchi method under following condition: pressure. 90,100,140,170 bar, temperature. of 35, 40, 45, 50 °C, mean particles size: 250,500,710,1000 μm, flow rate 1,3,5,8 ml/s and dynamic time 30,50,90,120 min. The optimizing conditions for SCE and SF-CO 2 concentration are: 90 bar, 45 °C, 500 μm, 5 ml/s, 120 min and 90 bar, 35 °C, 250 μm, 1 ml/s, 30 min. SCE total yield and CO 2 concentration... 

Novel high capacity swelling nanoporous hydrogel (NPH) was synthesized via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) hybrid backbone, after hydrolysis of this system. The Taguchi method as a strong experimental design tool was used for its optimized synthesis. The Taguchi method was applied for the experimental and standard 9 orthogonal array (OA) with four factors and three levels for each factor. A series of NPHs were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of... 

In this study, the artificial neural network (ANN) and the Taguchi method are employed to optimize the radial force and strain inhomogeneity in radial forging process. The finite element analysis of the process verified by the microhardness test (to confirm the predicted strain distribution) and the experimental forging load published by the previous researcher are used to predict the strain distribution in the final product and the radial force. At first, a combination of process parameters are selected by orthogonal array for numerical experimenting by Taguchi method and then simulated by FEM. Then the optimum conditions are predicted via the Taguchi method. After that, by using the FEM... 

The effects of H2O/SiO2, TMAOH/SiO2, Na/(Na+K), and SiO2/Al2O3 ratios in the parent gels on the crystallization of nanoparticles of T-type zeolites were studied. A Taguchi orthogonal experimental design with the above-mentioned parameters (each at three levels) was used to optimize the experiment parameters by the analysis of variances (ANOVA). Applying the Taguchi method significantly reduced the time and cost required for optimization. The synthesized products were characterized by X-ray diffraction and scanning electron microscopy. As a result of the Taguchi analysis, H2O/SiO2 and TMAOH/SiO2 were the most influencing parameters for the synthesis of zeolite T. © 2009 WILEY-VCH Verlag GmbH...