Orthogonal Array Method Research Articles

Development of high biomass and lipid yielding medium for newly isolated Rhodotorula mucilaginosa

Conversion of plant-based biomass into biofuels has been singled out as a way to achieve economically viable production chains. Over past few decades development in yeast oil production have been witnessed, which includes isolation of high lipid accumulating strains, understanding the metabolic pathways for oil production, genetic engineering strategies for overproduction of lipids and optimization of cultivation processes for converting lignocellulose biomass to oil. In the present investigation, screening, isolation and characterization of novel oleaginous yeast from oil refinery was carried out. The strain was identified as Rhodotorula mucilaginosa by 26s rRNA sequencing (Accession Number: KX533469). Glucose and peptone were identified as best carbon and nitrogen source for high biomass induction. Further, two-stage optimization using taguchi orthogonal array method and multi objective optimization using genetic algorithm was applied for the development of an optimized medium. Malt extract was found to be a key influencing factor in both biomass and lipid induction with high S/N ratio, followed by peptone and glucose. Batch bioreactor studies revealed that the lipid productivity follows mixed growth associated pattern with the higher lipid accumulation of 0.25 g/g biomass.

Investigation of the stability on boring tool attached with double impact dampers using Taguchi based Grey analysis and cutting tool temperature investigation through FLUKE-Thermal imager

This article focuses on the investigation of machining characteristics of double impact dampers attached with boring tool and grey relational analysis (GRA) based multi-objective optimization for lower tool wear and better cutting force. Taguchi based orthogonal array method was exploited to formulate the experimental plan for the boring operation. Considering impact damper positions, speed and depth of cut as the input control factors, the output responses such as cutting force and tool wear were obtained from the L27 orthogonal array. ANOVA results exposed that damper position and speed had more effect on tool wear and cutting force respectively than depth of cut. Based on the obtained output response for cutting force and tool wear a comprehensive mathematical model was developed. The developed mathematical model for tool wear and cutting force predicted values similar to that of experimental results. The obtained result was corroborated clinched Fluke thermal image analyzer. Thermal imaging result showed that the optimized cutting conditions gives low tool temperature there by reduced tool wear can be obtained. Multi-objective criteria optimization was done through GRA technique and the recommended optimum parameters set provides better cutting force (Cf) of 342.47 N and less tool wear (Tw) of 0.22 mm.

Performance Evaluation of Carbon-based Heterogeneous Acid Catalyst Derived From Hura crepitans Seed Pod for Esterification of High FFA Vegetable Oil

Efficient and recyclable heterogeneous catalysts from low-cost material is a research target in biodiesel industry to reduce production cost and minimize waste generation. The performance of carbon-based heterogeneous acid catalysts prepared from Hura crepitans seed pod via partial carbonization and sulfonation was evaluated in this study. Different catalysts, 0HuSO3H, 30HuSO3H, 60HuSO3H, 90HuSO3H, and 120HuSO3H, obtained by varying preparation conditions were characterized using emission scanning electron microscope, Fourier transform infrared spectroscopy, X-ray powder diffraction, and thermogravimetric and titrimetric analyses. The activity of the catalysts towards esterification of high free fatty acid-containing H. crepitans seed oil was assessed. Effects of process parameters, temperature, catalyst load, methanol/oil ratio, reaction time, and their various optimum levels on the esterification reaction, were investigated using Taguchi L9 orthogonal array method of optimization. The results showed that the H. crepitans seed pod-derived solid acid catalysts exhibited superior catalytic properties primarily due to high acid density (2.0 mmol/g). The resident time of carbonization before sulfonation showed a strong influence on the acid site density, pore sizes, hydrophobicity, and acid site retention capacity. The optimum process conditions as predicted by the optimization model gave 94.81% ester conversion. The catalyst was effective up to four cycles with only 1.44% decrease in activity.

Parametric Analysis of Magnetorheological Strut for Semiactive Suspension System Using Taguchi Method

Magnetorheological (MR) strut is among the leading advanced applications of semi-active suspension systems. The damping force of MR damper is controlled by varying the viscosity of MR fluid. In this work, the viscosity of MR damper varies by changing the current from 0.5A to 0.7A. The design of experiments is taken into account in concert with the product/process development as one completely advanced tool. The parameters used for ride comfort optimization are sprung mass, spring stiffness, tire pressure, current, and cylinder material with two levels of each. Taguchi orthogonal array method is used to select the best results by parameter optimization with a minimum number of test runs. In this paper, from Taguchi L16 array and S/N ratio analysis, it is observed that the cylinder material with Al and CS for damper cylinder is a key parameter for performance measure of semi-active suspension system. From regression analysis, a linear mathematical model is developed for Al and CS as cylinder materials. The interaction of cylinder materials with all four parameters is plotted. The methodology implemented for measurement of acceleration as a ride comfort is as per IS 2631-1997. The more economical model of magnetorheological damper will motivate Indian auto industry to broader applications.

Efficient Optimum Design of Metal with Strong Adhesion to Ceramics with a Combination of Orthogonal Array and Response-Surface Method

Efficient Optimum Design of Metal with Strong Adhesion to Ceramics with a Combination of Orthogonal Array and Response-Surface Method

Experimental analysis on tribological behavior of fiber reinforced composites

The use of fiber reinforced composites are widely used in many application such as automobile, aircraft manufacturing because they are cost effective and offers high strength, availability and weight ratio compared to other composites with similar applications. In this work, polyester was selected as a matrix material to prepare a composite specimen reinforced with sisal, banana, kenaf, carbon fiber and rice husk with different compositions. Composite specimen is prepared and Taguchi’s L9 orthogonal array method is used to study the Tribological behavior. The test specimen of composite material had been prepared using compression molding method and the same was tested using experimentally to determine the mechanical properties. The equipment used for the experimental work is pin on disc. The weight was measured before and after the experiment is conducted. The effects of the Tribological operating parameters applied load, sliding velocity and sliding distance on the frictional and wear performance of fiber reinforced composites are demonstrated. It was observed that the wear response of the specimens is influenced by the applied load, sliding distance and the speed.

Improvement of delta-endotoxin production from local Bacillus thuringiensis Se13 using Taguchi’s orthogonal array methodology

Abstract Objective The insecticidal activity of Bacillus thuringiensis directly depends on the yield of delta-endotoxins. In this study, various nutritional and cultural parameters influencing delta-endotoxin synthesis by a local isolate of B. thuringiensis Se13 were investigated using Taguchi methods. Methods In the first experiment, four factors, incubation period, incubation temperature, initial pH and medium, each at four levels, were selected and an orthogonal array layout of L16 was carried out. In the second experiment, Taguchi’s orthogonal array method of L27 was used to evaluate the effects of the different concentration of medium components. Taguchi’s signal–noise ratio and variance analysis were applied to determine the effect of the factors. After each experiment, verification studies were carried out using determined optimum conditions. Results The optimum conditions for incubation period, incubation temperature, initial pH, and medium determined as 72 h, 30°C, pH 9, and M4 medium, respectively. In the second experiment, soybean flour (5%), glucose (5%), KH2PO4 (0.3%), K2HPO4 (0.1%), MgSO4 (0.4%) were determined as the optimum conditions. The delta-endotoxin yield was elevated to 1559.25 μg mL−1 when the factors were adjusted to optimum level. Conclusion Optimization using the Taguchi method appeared to be a good choice for the overproduction of delta-endotoxin.

A New Model for RF Ablation Planning in Clinic.

Numerical simulations provide effective way to acquire detailed temperature field during radiofrequency ablation (RF). Based on the patient's real electrical resistance and RF power, we have designed a theoretical model suitable for clinical treatment planning. The human body is assumed to be two cylinders with the inner cylinder simulating the liver with real liver electrical conductivity, while the electrical conductivity of the out cylinder adjusted to match the real resistance recorded when treated with RFA. The orthogonal-array method has been applied to analyze the impact of the main geometric parameters. Results show that a limited range of model parameters with the same resistance and power condition results in similar prediction of ablation range. In addition, RF heating experiments have been performed in the liver of a live pig to validate this model. The simulated temperature fits well with the real temperature. The comparison of the results predicted using the proposed model and previous models finds that the previous uniform-electrical-conductivity model would significantly underestimates or overestimates the ablation range based on the magnitude of the electrical resistance recorded.

Processing of alumina ceramics by abrasive waterjet- an experimental study

Abrasive water jet machining (AWJM) is a non-conventional material removal process. It is superior to any other cutting techniques for processing various materials, particularly in processing difficult to cut materials. It is highly recommended for machining ceramics and composite materials. This paper attempts to investigate abrasive water jet machining of alumina ceramics, which finds its wide application in industries, owing to its striking mechanical properties such as high strength, corrosion and wear resistance. Experiments are designed according to Taguchi’s orthogonal array method. Analysis of variance (ANOVA) and regression equations were developed to evaluate the significant process parameters affecting the kerf characteristics. Here in this work, the input parameters include water pressure, abrasive flow rate, and traverse speed whereas the output responses include taper angle, surface roughness, and material removal rate. The results affirmed that all the three input parameters significantly affected the output responses. Optimum value of MRR, surface roughness and taper angle were measured as 62.02mm3/sec, 5.01µm and 0.2080, respectively.

Robust Optimal Operation of AC/DC Hybrid Microgrids Under Market Price Uncertainties

Energy management system (EMS) is responsible for the optimal operation of microgrids. EMS adjusts its operational schedule for near future by using the available information. Market price signals are generally used for the operation of microgrids, which are obtained by using estimation/ forecasting methods. However, it is difficult to precisely predict the market prices due to the involvement of various complex factors like weather, policy, demand, errors in forecasting methods, and fuel cost. Therefore, in this paper, the uncertainties associated with the real-time market price signals (buying and selling) are realized via a robust optimization method. In addition to market price signals, uncertainties associated with renewable power sources and forecasted load values are also considered. Initially, a deterministic model is formulated for an ac/dc hybrid microgrid. Then a min–max robust counterpart is formulated by considering the worst-case uncertainties. Finally, an equivalent mixed integer problem is formulated by using linear duality and other optimality conditions. The developed model can provide feasible solutions for all the scenarios if the uncertainties fluctuate within the specified bounds. The effect of market price uncertainties on internal power transfer and external power trading, operation cost, the state-of-charge of energy storage elements, and unit commitment of dispatchable generators is analyzed. Taguchi’s orthogonal array (OA) method is used to find the worst-case scenario within the specified uncertainty bounds. Then, Monte Carlo method is used to generate various scenarios within the uncertainty bounds to evaluate the robustness of the selected scenario via Taguchi’s OA method. Finally, a violation index is formulated to evaluate the robustness of the proposed approach against the deterministic model. Simulations results have validated the robustness of the proposed optimization strategy.

Design of Ceramic Materials with Strong Adhesion to Resin with a Combination of Orthogonal Array and Response-Surface Method

Design of Ceramic Materials with Strong Adhesion to Resin with a Combination of Orthogonal Array and Response-Surface Method

Optimization in resistance spot welding of CR3 sheets by embedding WC powder at the lap joint

In this work Tungsten Carbide (WC) powder has been embedded at the interface of Lap joint through Resistance Spot Welding (RSW). The idea of using WC powder at the interface is to make composite in the nugget as WC has good wetting ability with Iron(Fe). The factors that could influence the Tensile Shear Load(TSL) are welding current, Electrode pressure, weld time and number of pulse. All other factors like squeeze time, hold time, off time are kept constant. The influence of current, electrode pressure, weld time and number of pulse on the nugget diameter and TSL were studied using L9 orthogonal array and Taguchi method. From the results we could infer that the influence of weld current, weld time and number of pulse are significant.

Efficient parameter estimation of software reliability growth models using harmony search

The primary challenge of software reliability growth model is to find the unknown model parameters that are used to validate on software failure dataset. Though, numerical estimation technique plays a vital role in parameter estimation of software reliability growth models, they are not optimal as they suffer from constraints sucha as sample size, biasing, and initialisation of parameters. In this study, a parameter estimation of software reliability growth model that utilises a variant of harmony search is proposed. Extensive experiments are conducted on seven different software datasets of varying complexity. A robust experimental setup is developed employing an orthogonal array and Taguchi method. Two-fold performance comparisons are performed. First, the authors tested their proposed approach against Cuckoo search and numerical method (least square estimation) considering mean square error and Theil's statistics as a quality measure. Second, the authors applied statistical tests are performed that demonstrate the superiority of their approach over the others. The underlying motivation to conduct this study is to motivate researchers to utilise their approach for a better estimation of model parameters.

Investigation of various process parameters on the solubility of carbon dioxide in phosphonium-based deep eutectic solvents and their aqueous mixtures: Experimental and modeling

This research presents the application of predictive regression model such as quadratic regression for estimation of CO2 solubility in deep eutectic solvents namely allyltriphenylphosphonium bromide-triethylene glycol (ATPPB-TEG) into different molar ratios and their aqueous solutions. In doing so, a design of experiment (DOE) was applied based on Taguchi L18 orthogonal array method. Four factors, namely pressure, temperature, molar ratio and water/DES concentration in mixture were selected as input parameters of model. The output parameter of model was the CO2 solubility in terms of mole fraction of CO2 (XCO2). A quadratic regression model was developed after validation and confirmation through several strong approaches. The results disclose that the prediction of developed quadratic regression model is in acceptable agreement with experimental solubility data. The overall R-squared (R2) and absolute relative error (ARE) values of proposed quadratic regression model were 0.9966 and 0.0725, respectively. Moreover, analysis of variance (ANOVA) indicates that pressure is the most significant factor influencing the XCO2. Finally, the signal to noise (S/N) ratio shows that the highest levels for pressure, concentration of DES in mixture, and molar ratio, and lowest level for temperature are the optimal levels of input parameters to obtain the highest CO2 solubility in this system. The developed quadratic regression model and correlation are effective and provide quick, reliable and accurate predictions of CO2 solubility in DESs without carrying out any time consuming, difficult and expensive experimental measurements. To the best of our knowledge, this is the first time a regression model was developed for prediction of CO2 solubility in DESs and their aqueous solutions.

Characterizetion of Flexural Strength, Warpage and Shrinkage of Polypropylene-Nanoclay-Nanocomposites Blend with Gigantochloa Scortechinii.

This paper presents the characterization of Flexural Strength, Warpage and Shrinkage of reinforcement gigantochloa scortechinii fibre. The content of fiber were fixed at 0 wt.%, 3 wt.% and 6 wt.% in uniform increased. The selected injection moulding processing conditions were packing pressure, melt temperature, screw speed and filling time. The quality factors that need to be improved upon the characterization were flexural strength, warpage and shrinkage. This research started by drying the Gigantochloa Scortechinii fibres at 120°C. After that, 3 wt.% of the fibres were mixed with 81 wt.% of polypropylene, 15 wt.% of polypropylene grafted maleic anhydride (compatibilizer) and 1 wt. % of nanoclay. Samples with 6 wt.% of fibers were also prepared for comparison purpose. The mixing process was performed by using Brabender Lab-Compounder KETSE 20/40 and the pallets were produced using used Brabender® pelletizer with diameters of 1 to 4 mm. The optimisation process was accomplished by adopting the Taguchi L9 orthogonal array method. According to the results, for 0 wt.% GS, the flexural strength is 30.0082 MPa, the warpage is 0.0030000 mm and the shrinkage is 0.0003830 mm at packing pressure 40%, melt temperature 165°C, filled time 2 seconds and screw speed 35%. For the result 3 wt.% GS, the flexural strength is 32.2477 MPa, the warpage is 0.006670 mm and the shrinkage is 0.0003830 mm at packing pressure is 35%, melt temperature 165°C, filled times is 1 seconds and screw speed is 30%. While for the 6 wt.% GS, the results of the flexural strength is 36.9084 MPa, the warpage is 0.0066700 mm and the shrinkage is 0.0003830 mm at packing pressure is 35%, melt temperature 165°C, filled time is 2 seconds and screw speed is 30%. The existence of Gigantochloa Scortechinii fibre was also proven to effect significantly towards flexural strength with 6% increasing value ordering from 0 wt.% GS to 6 wt.% GS. while, the warpage value increasing from 0.003000 mm to 0.00667 mm and the shrinkage was state remain same value for 0, 3 and 6 wt.% of GS causes the result difference 0.000001 for each. In conclusion, the charactization of the flexural strength, the warpage and the shrinkage of the polypropylene-nanoclay-Gigantochloa Scortechinii had been achieved, and the existence of fibre obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products.

Optimization Analysis of Process Parameters of Friction Stir Welded Dissimilar Joints of Aluminium Alloys

Friction stir welding (FSW) is one of the new technique for welding materials in solid state welding process. In this proposed work we are using FSW to join the two dissimilar alloys of aluminium. The 6mm thick aluminum plates of aluminium 5086 and aluminum 7075 plates are considered for welding. These have been considered due to their application in various fields. In this experimental process Taguchi’s L9 orthogonal array method is used for optimizing the three process parameters namely rotational speed, axial force and welding speed. To produce a better joint the tensile strength is predicted for the optimum welding parameters and also their percentage of contribution is calculated, by applying the effect of analysis of variance. Depends upon the experimental study, the rotational speed is found better over the other process parameters, which enhances the quality of the weld. The tensile strength has been found for the optimum parameters and the result found during the experiment was 290Mpa which was higher than the base metal strength of aluminium 5086 alloy. The SEM fractograph analysis was done on the optimum parameters welded joints to show the fracture behaviour of tensile test which justifies the visual inspection results of brittle and ductile failures.

THE OPTIMIZATION OF SURFACE ROUGHNESS OF AZ91D MAGNESIUM ALLOY USING ANOVA IN BALL BURNISHING PROCESS

Ball burnishing is a simple, cost-effective and fast finishing process generally applied to better the surface roughness of machine parts. In this study, the Taguchi L18 orthogonal array method is used to find the optimal surface roughness in ball burnishing of AZ91D magnesium alloy. The orthogonal array, the signal-to-noise ratio, and ANOVA (analysis of variance) method is employed to study the performance characteristics in ball burnishing process of AZ91D alloy bars. The purpose of this study is to perform an ANOVA to determine the effects of the (burnishing force, burnishing speed, feed rate and number of passes parameters) on the surface roughness data obtained after the ball burnishing applied to the AZ91D bars. The optimum burnishing parameter was determined based on signal-to-noise (S/N) ratio. Data was analyzed by means of the ANOVA method. The main results of the statistical analysis highlight the great influence of the feed rate, burnishing force and number of passes on surface roughness among the set of factors and their interactions considered.

Optimization of friction and wear behaviour of Al–Si3N4 nano composite and Al–Gr–Si3N4 hybrid composite under dry sliding conditions

The tribological behaviour of gravity die stir cast LM6 alloy with graphite (Gr) and silicon nitride nanoparticles was investigated. Al–Gr–Si3N4 hybrid composite, Al–Si3N4 nanocomposite and Al–Gr nanocomposites were separately fabricated to investigate their frictional and wear characteristics under dry sliding conditions. EDS was used to ensure the uniform presence of nano Si3N4 and graphite in the cast. L9 orthogonal array method was chosen to conduct the experiments to study the effect of different applied loads (20, 30 and 40 N) and sliding distances (1, 2 and 3 km). The results showed that the respective wear rate and coefficient of friction (COF) decreased by 25% and 15% for hybrid composite when compared with those of Al–Si3N4 nanocomposite whereas the wear rate and COF of Al–Gr was found to be very minimal. The micro Vickers hardness of the hybrid composite was 14% more than that of the simple nanocomposite and there was not much notable variation for Al–Gr and Al–Si3N4 nanocomposite materials. Scanning electron microscope was used to analyze the worn surface and subsurface, from which it was noted that the predominant wear mechanisms observed were abrasive for nanocomposite and both abrasive and adhesive mechanism for hybrid composite. Analysis of variance (ANOVA) and F-test were used to check the validity model and to determine the significant parameters affecting the wear rates.

Experimental study of the influence levels of different vehicle seat adjustments on the fore-and-aft modal characteristics using the orthogonal array method

The vehicle seat modal characteristics (in particular, the first resonant frequency and the corresponding modal shape) play important roles in the seat design and the ride comfort. This paper investigated the relationship between the first modal characteristics and the positions of the adjusters on the vehicle seat. There are four adjusters on the vehicle seat to change its position so as to match the driver’s somatotype, the driving and the sitting habits. Different seat positions inevitably cause changes in the resonant frequency. An orthogonal array method was adopted to evaluate the influence levels of the adjusters by using a Pareto chart. It was found that the first modal (fore-and-aft) shape is almost uninfluenced by the variations in the adjuster positions, whereas the first modal frequency is greatly influenced by the changes in the adjuster positions. The first modal frequency is most affected by the variation in the slider position, followed by the variation in the headrest adjuster position, the variation in the recliner position and the variation in the height adjuster position.

Highly biocompatible chitosan with super paramagnetic calcium ferrite (CaFe2O4) nanoparticle for the release of ampicillin

The CaFe2O4 nanoparticles (CFNP) were synthesized using the solution combustion method. The CFNP-chitosan-ampicillin was prepared by the ionic gelation method using tripolyphosphate (TPP). The CFNP, chitosan-CFNP, chitosan-CFNP-ampicillin materials were characterized by XRD, FT-IR and TGA analysis in order to evaluate the particle nature and size, the presence of functional groups and their thermal stability. The FESEM and EDAX analysis were performed to understand the surface morphology of the materials and the presence of CFNP in the material, respectively. The vibrating sample magnetometer (VSM) analysis was performed to analyze the magnetic property of the chitosan-CFNP material. The squareness value of 0.1733 obtained by VSM measurements indicates the super paramagnetic nature of chitosan-CFNP. Taguchi orthogonal array method was applied to identify the significant impacting parameters for maximizing the drug encapsulation of chitosan-CFNP. The drug release studies showed that the drug was released rapidly in acidic medium as compared to the basic or neutral medium. The drug release kinetic data were fitted with different linear kinetic model equations and the best fit was obtained with Korsmeyer-Peppas model. The model drug ampicillin release from chitosan-CFNP was tested against staphylococcus epidermis bacteria through disc diffusion method for checking biocompatibility and antibacterial activity.