Full Factorial Design Approach Research Articles

Electro-Chemical Impedance Spectral (EIS) Study of Patinated Bronze Corrosion in Sulfate Media: Experimental Design Approach

The aim of the present investigation was to model the experimental conditions of tin bronze patination using full factorial experimental design. In this sense, a full factorial design approach was developed to model the corrosion behavior of patinated tin bronze alloy in sulfate electrolyte. Three experimental factors (the immersion time in the chloride electrolyte, the potential limit for the anodic sweep Elim, and the potential scan rate) were chosen to identify the significant factor on the patina growth process at the bronze substrate. The experimental responses were the kinetic parameters extracted from the electro-chemical spectra (EIS) for eight different experiments. An equivalent electrical circuit containing an electrolyte resistance (Re), a double layer capacitance (CPEdl), a charge transfer resistance (Rt) and Gerischer element (G), was developed to model the patinated bronze corrosion process. The electro-chemical spectra (EIS) show that the corrosion process of the patinated bronze alloy occurred from a chemical reaction is followed by an electrochemical one. Analysis of the experimental responses showed that while the scan rate is the most influent factor for the corrosion potential (Ecorr), the electrolyte resistance (Re), and the double layer capacitance CPEdl variation, the potential limit is the significant factor for charge transfer resistance Rt, reciprocal of the admittance parameter Y0 and the effective transfer rate of the chemical reaction k variation.

Magnetic field-assisted photochemical machining (MFAPCM) of SS316L

ABSTRACTIn this paper, a new technique of photochemical machining (PCM) process has been described. The objective of this study is to investigate the effect of applying a magnetic field on the PCM of AISI 316 L stainless steel. The experiments were planned and conducted using a Full Factorial Design (FFD) approach. The control parameters selected were magnetic field, temperature, concentration and time. The analysis of the results shows significant improvement in the etch rate due to the application of a magnetic field. The highest etch rate was achieved at a concentration of 700 g/l, at the temperature of 60°C in a static magnetic field. The improvement of the etch rate is 2.5 times with the application of magnetic field as compared to the conventional PCM process.

An artificial immune algorithm for ergonomic product classification using anthropometric measurements

Abstract Product classification using anthropometric measurements leads to ergonomic product design and user satisfaction. We propose an effective artificial immune algorithm (AIA) to classify ergonomic products with multi-criteria anthropometric measurements and tune the AIA parameters with a full factorial experimental design approach. We demonstrate the applicability and efficacy of the proposed algorithm by considering the anthropometric measurements of the hand, developing an ergonomic computer mouse, and classifying consumers into three categories. The resulting classifications are compared with expert opinions to facilitate the conformity of the computer mouse to user requirements.

Artificial neural network and regression-based models for prediction of surface roughness during turning of red brass (C23000)

In this study, models based on artificial neural networks (ANN) and regression analysis were developed to predict the surface roughness during the turning of red brass (C23000), using a high-speed steel (HSS) tool. The full factorial design approach was used for experimentation to achieve a high level of confidence. The influence of cutting parameters (cutting speed, feed rate and depth of cut) on the surface roughness was also investigated using ANOVA. The ANN model having hyperbolic tangent sigmoid (tansig) and linear (purelin) transfer functions was used for the hidden and output layers respectively. The regression model based on the power law was also developed. It was found that at a speed of 840 m/sec and depth of cut of 0.1 mm, the surface roughness changed by 11.3% when changing the feed rate by 5.6%. However, the surface roughness changed by only 6.8% when changing the velocity by 6% at the feed rate of 0.12 mm and depth of cut 0.1 mm. A similar trend was observed for different feed rates, speeds and depths of cut. It was concluded that the feed rate was the most significant factor influencing the surface roughness, followed by the depth of cut and cutting speed. The models developed were compared using statistical methods: coefficient of determination (R 2 ) and mean absolute percentage error (MAPE). R 2 was found to be 0.99784 and 0.9969 for the ANN and regression models, respectively. Similarly, MAPE was found to be 1.4243% and 4.8161% for the ANN and regression models respectively. It was concluded that the ANN model is a superior choice over the multiple regression model for the prediction of surface roughness. The accuracy of the ANN can be attributed to its ability to capture the nonlinearities involved in the turning operation.

FACTORS IDENTIFICATION FOR COAL BRIQUETTES MANUFACTURING USING STATISTICAL EXPERIMENTAL DESIGN APPROACH

Coal briquettes are mostly manufactured through conventional methods in developing countries including Pakistan. Shortages of energy resources across the globe have pushed companies to manufacture those products with least possible costs by using signifcant factors. Indeed, the role of statistical design of experiment in general and factorial design in particular is vital in identifying these signifcant factors in comparison to the conventional techniques. This paper provides a statistical approach towards manufacturing of coal briquettes in Northern Province of Pakistan. Binder composition, pressure, particle size, and coal type are analyzed for higher calorifc value and compressive strength simultaneously. Experiments are conducted in order to obtain the response of desired variables for the given three levels of each factor. Full factorial design approach with analysis of variance (ANOVA) is deployed to get the optimum values of the response variables under the given conditions.

Regenerated cellulose capsules for controlled drug delivery: Part III. Developing a fabrication method and evaluating extemporaneous utility for controlled-release

In this article, we describe a method to utilize cellulose dissolved in dimethyl sulfoxide and paraformaldehyde solvent system to fabricate two-piece regenerated cellulose hard shell capsules for their potential use as an oral controlled drug delivery a priori vehicle. A systematic evaluation of solution rheology as well as resulting capsule mechanical, visual and thermal analysis was performed to develop a suitable method to repeatedly fabricate RC hard shell capsule halves. Because of the viscoelastic nature of the cellulose solution, a combination of dip-coating and casting method, herein referred to as dip-casting method, was developed. The dip-casting method was formalized by utilizing two-stage 22 full factorial design approach in order to determine a suitable approach to fabricate capsules with minimal variability. Thermal annealing is responsible for imparting shape rigidity of the capsules. Proof-of-concept analysis for the utility of these capsules in controlled drug delivery was performed by evaluating the release of KCl from them as well as from commercially available USP equivalent formulations. Release of KCl from cellulose capsules was comparable to extended release capsule formulation.

Hydrothermal liquefaction of a wastewater native Chlorella sp. bacteria consortium: biocrude production and characterization

ABSTRACTAlong the recent developments of biofuel production, the hydrothermal liquefaction (HTL) of microalgae appears as a major process step which could take advantage of converting the whole microalgae content instead of only extracting its lipid content. This study presents the HTL conversion of a microalgae Chlorella sp. bacteria consortium using a batch type reactor. The experiments were carried out using a full factorial experimental design approach, where the main chosen factors were the temperature, the residence time at maximum temperature and the dry-matter-to-water ratio. The biocrude oil is the targeted product characterized along this work; its production and its composition were studied. The yields of biocrudes approach other microalgae studies using pure strains of microalgae and batch-type reactors. Maximum yields (37%daf) and lowest O/C ratio (0.167) were obtained at the highest severity conditions (310 °C for 55 min and 0.15 dry-matter-to-water ratio). The energy return on energy invested (EROEI) of the process has been determined. The simulated distillation by thermogravimetric analysis (Sim-Dis-TGA) was conducted on the different obtained biocrude and no significant effect was observed with respect to five evaporation ranges among the studied conditions. GC-MS characterization of biocrude presents the 10 relatively most abundant components for each studied condition.

Mechanical Characterization and Machinability Behavior of Annealed AISI D6 Cold Working Steel

Tool steels in metal forming industry are exposed to complex and aggressive conditions due to multiple effects (mechanical, thermal, or tribological loading) and require defined mechanical properties. Also machining of tool steel with poor machinability like AISI D6 to manufacture form tools is an extremely difficult task. This paper investigates the microstructural, mechanical, and machining behavior of AISI D6 steel in annealed and hardened conditions. Various mechanical tests indicated good hardenability, improved surface hardness, and phenomenal improvement in tensile strength but extremely poor resistance to impact in both annealed and hardened condition for this steel. The machining characteristics of AISI D6 steel were evaluated using a 2k unreplicated full factorial design approach and statistical techniques have been used to assess and identify the significant factors, namely, cutting speed, feed, depth of cut, and approach angle, in minimizing surface roughness and main cutting force while machining this steel with a carbide tool. It was found that the depth of cut, feed, and approach angle are the most significant factors affecting the surface roughness and depth of cut and feed affect the main cutting force. Cutting speed has no effect on surface roughness and main cutting force in machining of the steel in annealed condition.

Acid-catalyzed esterification of castor (Ricinus communis) oil: optimization through a central composite design approach

The present investigation emphasizes the dynamic modeling and optimization of acid esterification of non-edible castor (Ricinus communis) oil towards reduction of free fatty acid (FFA) content considering four process parameters, namely reaction time (0–4 h), reaction temperature (40–80°C), catalyst concentration (0.25–3.25 w/w) and molar ratio of methanol to oil (1:1–20:1) by the response surface methodology 24 full factorial central composite design approach. A quadratic model was developed to evaluate considerable interactive effects on FFA. Reaction temperature exhibited the most significant effect among all of the process variables. Optimal conditions during which the FFA was reduced from 4.04 to 1.08% were: 1% w/w concentrated H2SO4, 15:1 molar ratio of methanol to oil, reaction temperature 50°C and reaction time 2.09 h. Experimental verification of the predicted condition ensured an actual FFA of 1.14%. The small error (0.0634) between the predicted and actual FFA values ascertained the validity and accuracy of the model in representing the experimental data and predicting conversion at any condition within the studied range. Hence, this pre-treatment under optimized conditions could overcome the major constraint of high FFA, thereby rendering suitability for base transesterification.

Development of a model for the prediction of hydrodynamics of a liquid–solid circulating fluidized beds: A full factorial design approach

Hydrodynamics of a liquid–solid circulating fluidized bed (LSCFB) system has a significant impact on the reactor design. In the present study, statistical design approach was adopted to model the hydrodynamic behavior of an LSCFB in terms of average solids holdup and solids circulation rate. Primary liquid velocity, auxiliary liquid velocity, solids inventory and liquid viscosity are the input variables, called factors, which affects the system. Average solids holdup and solids circulation rate are called responses of the system. A full factorial design approach with four factors and three levels of the factors were considered. Various models such as linear, two factor interaction, quadratic, and cubic models were tested for the adequacy. Within the range of experiments conducted, for both responses, the quadratic regression model is suggested. The model shows that some of the interaction effects between the factors are dominant. The developed model was verified by using various statistical tests. Also, the model was validated using various experimental data sets chosen at different conditions. Results based on ‘R’ value, and deviations in parity plot were falling within agreement level. This suggests that the proposed model can be adopted for various processing applications in the LSCFB unit.

Effect of iron oxide nanocluster on enhanced removal of molybdate from surface water and pilot scale test

Abstract A novel combination of magnetic adsorptive and coagulative strategy which was applied to remove molybdenum (Mo) ions from surface water was investigated in this study. The ferromagnetic nanoclusters and ferromagnetic nanoclusters-ferric flocs composite coagulant were characterized in terms of typical properties, structure and morphological analysis (TEM, XRD, M – H hysteresis curves, particle size distribution). Different removal agents of Mo was investigated that the removal rate of Mo was ferromagnetic nanoclusters-FeCl 3 > FeCl 3 > AlCl 3 > TiCl 4 . Jar tests were employed to evaluate the removal performances. The coagulation performances of ferromagnetic nanoclusters-ferric flocs were compared under different pH conditions and dosages. Various factors influencing the removal of Mo(VI), e.g. pH, the dose of ferromagnetic nanoparticle, FeCl 3 , were conducted using a 3 3 full factorial design approach. The results show that the newly addition of ferromagnetic nanoparticles obviously had a trend to form cluster, especially magnetic force acted as a key role that may promote the formation of ferromagnetic nanoclusters. The better removal performance of Mo could be attributed to the co-effect of ferromagnetic nanoclusters and ferric flocs. Meanwhile, in order to satisfy the national drinking water criterion, the reinforce effect of ferromagnetic nanoclusters on reducing the concentration of ferric (Fe) ions in effluent makes sure that the content of ferric ions under 0.3 mg/L. The experimental results indicated that mechanism of the molybdate removal was a physical surface adsorption which might combine with chemical action.

Combined effects of reduced malaxation oxygen levels and storage time on extra-virgin olive oil volatiles investigated by a novel chemometric approach

Combined effects of oxygen level reduction in the malaxation headspace and storage time up to 6months on the volatile composition of a monovarietal extra-virgin olive oil (EVOO), obtained from cv. Carboncella olives, were investigated by applying a full factorial design approach (4 oxygen levels×4 storage times) on EVOOs extracted on an industrial scale in two mills, equipped with “two-phase” and “three-phase” centrifugation systems, respectively. The outcoming data were analysed by the chemometric technique called ANOVA-simultaneous component analysis (ASCA).Both reduction of oxygen malaxation levels and storage time significantly affected the volatile profile of the extracted EVOOs. Reduction of oxygen malaxation levels hindered the formation of lipoxygenase derived volatiles (hexanal, 1-hexanol, (Z)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-penten-1-ol, 2,4-hexadienals), whereas prolonged storage times were associated with increased levels of autoxidation products (octane, hexanal, C10 hydrocarbons) and other compounds that could originate from exogenous microbial activity (1-octen-3-ol, 6-methyl-5-hepten-2-one, benzaldehyde, methyl salicylate).

Investigations into a thiol-impregnated CaCO3-based adsorbent for mercury removal: a full factorial design approach

We demonstrated removal of Hg0 vapor by adsorbing it on thiol-impregnated calcium carbonate and assessed the significance of temperature and thiol mass in Hg0 removal.

Preparation, Characterization and Optimization of Poloxamer Solid Dispersions of a Poorly Water Soluble Drug Aprepitant

Aim: The aim of the present investigation was to enhance the dissolution rate of a poorly water soluble drug, aprepitant, by preparation of solid dispersion with hydrophilic carrier, poloxamer 188, using solvent evaporation method. Place and Duration of Study: Department of Pharmaceutical Sciences and Department of Emerging Life Sciences, Guru Nanak Dev University, Amritsar, Punjab, between August 2012 and July 2013. Study Design: Designs of experiments were carried out with two input variables, drug to carrier ratio (X1) and amount of solvent (X2). A total of 7 experiments were performed (4 factorial runs and 3 centre points) as per full factorial design. Percent dissolution efficiency at 60 min (DE60) was selected as the response variable. Pareto chart along with half probability plot were studied for determining the most significant process variables, which were modelled using ANOVA. Methodology: Solid dispersions of aprepitant with poloxamer 188 were prepared using the solvent evaporation method and studied systematically using an optimization technique. A 22 full factorial design approach was used for the optimization of process variables on dissolution characteristics. The optimized solid dispersion was characterized by dissolution studies, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry, X-ray powder Diffraction studies and Scanning Electron Microscopy. Results: The results of the experimental study confirm that the factors like drug to carrier ratio and solvent amount significantly influence the dependent variable DE60. A high level of drug to carrier ratio and low level of solvent amount were found to be suitable for maximum DE60. The use of factorial design approach helped in the optimization of the solid dispersion. The characterization of optimized solid dispersion (F5) demonstrated that the decrease in crystallinity of aprepitant and poloxamer 188 might be responsible for the enhanced dissolution rate. Analysis of dissolution data indicated the best fitting with first-order model. Conclusion: Dissolution enhancement of aprepitant was successfully obtained by preparing its solid dispersion with poloxamer 188 using solid evaporation method.

Experimental Investigations and Study of Tribological Behaviour of Alternate WC Coated Bearing Surfaces

Coated bearing surfaces exhibit relatively better tribological properties compared with non-coated surfaces irrespective of the coating technology used. An attempt is made to study the effectiveness of alternately coated bearing surfaces with hard material. Striped alternate coated bearing surface with hard material ends up with a bearing surface having alternate bands of soft and hard materials. I the current work Tungsten carbide is taken as hard coating material. A Circular MS (2%-C, 1.65%-Mn, 0.6%-Cu, and 0.6%-Si) disc with alternate WC coating has been developed with plasma spray technique and experiments are designed using full factorial design approach. Tribological properties like wear, coefficient of friction and frictional force were found by conducting number of experiments on both uncoated and coated disks. Pin-on-disk apparatus is used for experimentation. Significant factors were identified and models are developed by using regression analysis. ANOVA is used for analysing results. Experimental results for both the alternate coated and uncoated discs were analysed and correlated.

Removal of Cu2+ from copper flotation waste leachant using sepiolite- full factorial design approach

Copper flotation waste which is the product pyrometalurgical production of copper from copper ores contains materials such as iron, alumina, calcium oxide, silica, etc. Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals such as Zn, Co and Pb. A variety of techniques can be used for decontaminating and remediating copper slag. Environmental remediation technologies include in situ or ex situ techniques for decontaminating the polluted fields, such as soil-washing, physical separation, phytoremediation and leaching. The aim of the present study is to investigate the removal of the copper from copper flotation waste leachant using sepiolite. 2 3 full factorial design was employed to study the effect of three factors which are contact time, adsorbent dosage and pH at two levels.

Parametric Optimization of Heat Transfer from Triangular Fin Array Within a Rectangular Enclosure Using Design of Experiment (DOE): A Comparative Analysis

The increasing numbers of thermal management problems in the various electronic and computing equipments, emphasize the need of effective cooling systems. Although attachment of extended surfaces (fins) is the most proposed way to enhance the heat transfer rate but sometimes addition of fins may deteriorate the heat transfer rate. So, it becomes imperative to optimize the control parameters for maximum heat transfer enhancement. Numerous experimental investigations reveal the Rayleigh number, fin height, and fin spacing are the major influencing design parameters that affect the system performance. Determination of optimum parameters depends on the proper selection of suitable design of experiments at the product development phase. This paper compares and contrasts the general full factorial design approach with Taguchi’s design of experiments used for determination of optimum parametric design. These statistical approaches have been applied to the results of an experimental parametric study conducted to investigate the effect of influencing parameters on free convective heat transfer from triangular fin arrays in a horizontally oriented rectangular enclosure.

Optimum Design Parameters for Heat Transfer from Triangular Fin Array within a Rectangular Enclosure

This article outlines the evaluation of optimum parametric design for heat transfer analysis through triangular fin array within a vertically oriented rectangular enclosure using general full factorial design approach. This statistical approach has been applied to the conclusions of an experimental analysis conducted to explore the effects of fin height (L), fin spacing (S) and Rayleigh number (Ra) on free heat transfer from triangular fins attached to the heated bas plate within an air filled rectangular enclosure. The analysis of variance (ANOVA) technique has been used to find the significant effect of control parameters on response. The control parametric combination L=37.5 mm; S= 50mm; and Ra=773410 has been reported as the optimum parametric combination yielding maximum heat transfer rate for present study.

Bench-scale evaluation of drinking water treatment parameters on iron particles and water quality

Discoloration of water resulting from suspended iron particles is one of the main customer complaints received by water suppliers. However, understanding of the mechanisms of discoloration as well as role of materials involved in the process is limited. In this study, an array of bench scale experiments were conducted to evaluate the impact of the most common variables (pH, PO4, Cl2 and DOM) on the properties of iron particles and suspensions derived from the oxygenation of Fe(II) ions in NaHCO3 buffered synthetic water systems. The most important factors as well as their rank influencing iron suspension color and turbidity formation were identified for a range of water quality parameters. This was accomplished using a 24 full factorial design approach at a 95% confidence level. The statistical analysis revealed that phosphate was found to be the most significant factor to alter color (contribution: 37.9%) and turbidity (contribution: 45.5%) in an iron-water system. A comprehensive study revealed that phosphate and chlorine produced iron suspension with reduced color and turbidity, made ζ–potential more negative, reduced the average particle size, and increased iron suspension stability. In the presence of DOM, color was observed to increase but a reverse trend was observed to decrease the turbidity and to alter particle size distribution. HPSEC results suggest that higher molecular weight fractions of DOM tend to adsorb onto the surfaces of iron particles at early stages, resulting in alteration of the surface charge of iron particles. This in turn limits particles aggregation and makes iron colloids highly stable. In the presence of a phosphate based corrosion inhibitor, this study demonstrated that color and turbidity resulting from suspended iron were lower at a pH value of 6.5 (compared to pH of 8.5). The same trend was observed in presence of DOM. This study also suggested that iron colloid suspension color and turbidity in chlorinated drinking water systems could be lower than non-chlorinated systems.

MICRO-SCALE METHOD FOR SEPARATION AND QUANTIFICATION OF ATENOLOL AND HYDROCHLOROTHIAZIDE BY SEQUENTIAL INJECTION CHROMATOGRAPHY

A microscale stopped-flow separation manifold, which is termed sequential injection chromatograph (SIC), was exploited for separating and quantifying atenolol and hydrochlorothiazide. A short C18 separation column (4.6 × 25 mm) with a monolithic structure was used to offer a rapid and sufficient separation. Microscale fiber optic spectrometric devices were coupled with the SIC manifold for UV detection at 220 nm. The proposed SIC method was optimized, validated, and applied to both formulations single and binary mixture. The mobile phase composition (MPC) was optimized using the 23 full-factorial design approach while other conditions were optimized using the univariate approach. The optimum MPC was 40 µmol/L phosphate:methanol:acetonitrile (85:7.5:7.5, v/v/v) at pH 3.0. Other optimum conditions were 40 µL/s for flow rate and 40 µL for sample volume. Satisfactory separation with a resolution of 1.6 and numbers of theoretical plates of more than 630 was achieved. The interesting features of the proposed SIC method are the microliter-scale of the consumed volume of mobile phase (3.50 mL) and high sample frequency (23 samples/hr).