Response Surface Experimental Design Research Articles

Optimization of the Subcritical Butane Extraction of Tung Oil and Its Mechanism Analysis

Tung oil is an important dry grease. In order to overcome the deficiencies of traditional processes in oil production, the preparation of tung oil was carried out by the butane-subcritical method. A response surface optimization experiment was carried out based on Design-Expert software, and the best process parameters were obtained. The extraction temperature was 42.98 °C, the extraction time was 43.77 min, the particle size of the raw material was 38.88 mesh, and the oil yield of tung oil under this condition reached 67.437%. The fatty acid composition of tung oil was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS): the content of α-oleostearic acid was 74.99%, linoleic acid content was 8.83%, oleic acid content was 7.42%, palmitic acid content was 2.02%, and stearic acid content was 4.35%. Through the analysis of the oil sample obtained, five indicators showed that the process of obtaining oil products met the requirements of the national standard. By simulating the subcritical n-butane/tung oil dissolution equilibrium model, the miscible dynamic equilibrium of tung oil in subcritical n-butane was studied at temperatures in the range of 35–50 °C and an equilibrium time of 40 min, and the kinetic equations of oil extraction at different temperatures were obtained, with a coefficient of determination (R2) greater than 0.99. The oil extraction rate was up to 67.12 ± 0.05% under optimal extraction conditions through the optimization of univariate and response surface experimental design. Using 1stOpt data processing software, the data of tung oil extraction rate at different times were fitted, and it was found that the Patricelli model accurately elucidated the kinetic process of tung oil extraction through subcritical n-butane, with R2 greater than 0.99.

Decolorization of colored wastewaters with Turquoise Blue dye by the native Colombian fungus Leptosphaerulina sp. - Influence of operational parameters

Synthetic dyes are highly stable, offer a wide range of colors, and have easy industrial applications. Nevertheless, dyes become a problem in aqueous environments due to their long permanence and low biodegradability. White-rot fungi are useful to degrade dyes through their ligninolytic enzymes and/or biosorption. This work evaluated the effect of 2,5-dimethylaniline, glucose, ammonium tartrate, copper sulfate, pH, and temperature on the degradation of Turquoise Blue (TB) dye in aqueous solutions by Leptosphaerulina sp. (Colombian native fungus). Assays were developed applying a response surface experimental design, which found that the ammonium tartrate and pH are the most influential variables on TB removal. Leptosphaerulina sp. decolorizes aqueous solutions with TB (99%, at day 8), mainly through sorption (89%). Therefore, one of the significant findings from this study is that the Leptosphaerulina sp. biomass is a promising alternative as biosorbent, in comparison to physical-chemical traditional methods, for treating wastewaters polluted with dyes

Novel Self-Adaptive Shale Gas Production Proxy Model and Its Practical Application.

Recently, production optimization has gained increasing interest in the petroleum industry. The most computationally intensive and critical part of the production optimization process is the evaluation of the production function performed by the numerical reservoir simulator. Employing proxy models as a substitute for the reservoir simulator is proposed for alleviating this high computational cost. In this study, a new approach to construct adaptive proxy models for production optimization problems is proposed. An adaptive difference evolution algorithm (SaDE) optimized least-squares support vector machine (LSSVM) is used as an approximation function, while training is performed using a self-adaptive response surface experimental design (SaRSE). SaDE selects the optimal hyperparameters of LSSVM during the training process to improve the prediction accuracy of the proxy model. Cross-validation methods are used in the recursive training and network evaluation phases. The developed method is used to optimize the production of block gas reservoir models. Computational results confirm that the developed adaptive proxy model outperforms traditional regression methods. It is further verified that when the experimental data are updated, the alternative model still has high prediction accuracy when performing the objective function evaluation. The results show that the proposed proxy modeling approach enhances the entire optimization process by providing a fast approximation of the actual reservoir simulation model with better accuracy.

Studies on Modeling and Physicochemical Properties of Oil Extracted from Moringa stenopetala Seed

Moringa stenopetala, locally known as Shiferraw, is an indigenous vegetable tree native to southern Ethiopia and grown mainly for its food value. This study deals with the investigations of physicochemical characteristics of Moringa stenopetala seeds’ oil extracted using solvent extraction with food-grade hexane as a solvent and Analysis of Variance (ANOVA) of the extraction parameters. The seeds were collected from Adama located in Oromia, East Shewa Zone of Ethiopia, and they exhibit the average moisture, ash, fiber, protein, and oil contents of 6.3, 4.2, 2.3, 27.5, and 40.2%, respectively. Temperature, extraction time, and particle size had a significant p < 0.05 effect on the oil yield. According to the Experimental Design Response Surface Methodology (RSM) and ANOVA analysis, the optimum process parameters’ combination to find the highest oil yield was particle size of 0.83 mm, the temperature at 78.82°C, and extraction time of 5.13 hours. The model predicted oil yield was 39.7 ± 0.32%. The oil from Moringa stenopetala seed exhibits physiochemical characteristics of refractive index (40°C), 1.4625; viscosity 49.4 Cp; density at 25 °C, 0.9317 g/cm−3; saponification value, 191.4; peroxide value, 11.52 millieq O2/kg; iodine value of 89.21; and Acid Value (AV) 2.21 mg KOH/g. Fourier-transform infrared spectroscopy (FT-IR) analysis shows that the oil contains both ester carbonyl (C=O) functional groups saturated and unsaturated fatty acid. The physicochemical properties of Moringa stenopetala seeds were compared with other edible oil properties such as sesame, groundnut, olive, and sunflower seeds. The result shows that in the future Moringa stenopetala could be used as a substitute for other oil-bearing seeds sources, such as soybean, sunflower, and groundnut.

Esterification of Free Fatty Acid in Palm Oil Mill Effluent using Sulfated Carbon-Zeolite Composite Catalyst

Free fatty acid esterification (FFA) in palm oil mill waste (POME) was carried out using a sulfonated carbon-zeolite composite catalyst. The catalyst is synthesized with carbon precursor obtained from molasses, which is adsorbed on the surface of the zeolite and then carbonized and sulfonated with concentrated H2SO4 to form a sulfonated carbon-zeolite catalyst composite, which will be used for the esterification catalyst and the optimization process for the esterification reaction is carried out using the response surface methodology (RSM) and experimental central composite design (CCD). Importantly, the observed independent variables were temperature, catalyst weight, and reaction time to produce fatty acid methyl ester (FAME) products. The catalyst was successfully synthesized, which was shown from the SEM characterization strengthened by the presence of a sulfate group in the FTIR results and the calculation results of high acidity properties. Optimization of FFA esterification with SCZ catalyst obtained optimal conditions with a temperature of 79oC, a catalyst weight of 3.00 g, and a reaction time of 134 minutes with a FAME product of 93.75%, considering that the viscosity of biodiesel is below that required by the API.

Multiple objective optimization of a diesel engine fueled with Karanja biodiesel using response surface methodology

This study optimizes the fuel quality of a diesel fuel while using biodiesel blends as fuel. Using the response surface Design of Experiments and Taguchi approach, the effects of load, compression ratio, and mixture on thermal efficiency (BTE) and nitrogen oxides (NOx) were statistically investigated. All input parameter is examined. at four specific levels. The findings shows that the highest values for BTE and NOx were discovered when the load was at its highest level, while the optimum values for the other two input parameters were obtained at various levels. As an outcome, the response surface technique is utilized in addition to the Taguchi method to reduce variance. In this study, engine performance is optimised for Kusum Oil in terms of thermal efficiency (BTE) and nitrogen oxides (NOx) Using Taguchi's method, an optimised dataset of the input parameters, such as Engine Load (percent), Blend (percent), and Fuel CR, is generated, which is then input into the prediction methods, such as response surface methodology and multiple regressions. Based on the evidence collected, these approaches are also evaluated in terms of accuracy.Mathematical Regression model created using RSM-based design of experiments. Effects of operational conditions on CI engine emissions and performance the fuel for the analysis was biodiesel blends. RSM's desirability technique is used to optimise input parameters. Optimal process Engine Load (%) 100, Blend (%) 20 and CR18 with their proper effects parameters obtained are BTE (%) 27.3264, NOx (ppm). = 550.5.

Removal of Pb(II) from Aqueous Solution by Ceramsite Prepared from Isfahan Bentonite and γ-Alumina

Removal of lead from aqueous solutions was studied using nanocomposite absorbent of bentonite/-alumina. The novel absorbent was characterized using XRD, FT-IR and SEM-EDX. Absorption process optimization using response surface methodology (RSM) and experimental design was performed with central composite design technique. The effects of Pb(II) initial concentration, adsorbent dosage, and composite percentage on Pb(II) removal percentage and adsorption capacity were examined. The adsorption capacity of 166.559 mg/g and removal % of 82.9887 with desirability equal to 0.763 were obtained for optimal initial concentration of 200 mg•l-1, adsorbent dosage of 0.5 mg•l-1, and composite percentage of 7.08 % determined using RSM design. The equilibrium adsorption data were investigated by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. It was found that Freundlich isotherm model fits better compared with other models.

Optimization of Bacterial Nano-Cellulose Production in Bench-Scale Rotating Biological Contact Bioreactor by Response Surface Methodology

The main challenge in bacterial cellulose nanofibers production is low yield and high cost. The aim of this work is to optimize bacterial nano-cellulose production in the bench-scale rotating biofilm contact (RBC) bioreactor using experimental design. At all of experiments the Acetobacter Xylinum BPR2001 and culture medium molasses – CSL were used. Three effective factors in the three levels including rotation (10, 13 and 16 rpm), aeration (0.2, 0.5 and 0.8 vvm) and disk distance (1, 1.5 and 2 cm) were optimized by response surface experimental design. The optimum conditions of biocellulose production were rotation rate 13 rpm, aeration 0.5 vvm and disk distance 1.5 cm. The maximum dry weight of bacterial cellulose production reached 11.65 g/l in the 7th day, Which is one of the highest amounts of bacterial cellulose ever reported. Reduced quadratic models were used to final dry weight and moisture content of bacterial cellulose responses. ANOVA results showed the p-values were less than 0.05 that are significant models.

Response surface design of a thiol-ene polymer sealant to model adhesive strength

Commercial aircraft fuel tanks require sealants applied at contact points to prevent leakage or moisture contamination, but cure times for conventional sealants range from hours to days. Thiol-ene ultraviolet (UV) curable sealants have been a proposed material for these applications. However, selecting proper monomers and optimizing synthesis conditions for a figure of merit is an arduous process. Therefore, modeling the adhesive strength of a thiol-ene sealant was performed using a response surface design of experiment (DoE). Two separate crosslinking alkenes were separately combined with a thiol monomer, and a 6 mm thick polymer was synthesized at different cure temperatures, cure times, and with various solid filler material on an aluminum substrate according to a response surface design. The samples were then peeled off the substrate at a 180° angle, and peel strength was measured. The DoE utilized the peel data to derive a multivariable numeric function for the peel strength. Resulting contour data shows the system has not been fully optimized, but trends in the data show that future experiments should lean toward higher cure times and temperatures to maximize peel strength. Additionally, the resulting model equation can predict adhesive strengths near the studied conditions.

Optimization of Extraction and Purification of Polysaccharides from Veronicastrum axillare, and Evaluation of Their Biological Activities.

Veronicastrum axillare polysaccharides (VAP) were isolated by cellulase-assisted digestion. The optimum conditions (2 % cellulase, 47 °C for 2.5 h, then, 95 °C for 2.5 h, pH 4.1, solid/liquid ratio 1 : 7.6) were identified by a combination of single factor optimization and response surface DOE (design of experiment) methods, and achieved a yield of 4.7 %. Treatment with 1 % TCA for 10 min, then, 2 % DEAE-cellulose removed protein and colored impurities. Purified VAP retained most of the radical-scavenging activities and GES-1 cell protection capability in vitro, indicating VAP were the key active components of V. axillare. Some molecular features were identified by FT-IR and NMR analyses. The molecular weight was estimated from DOSY NMR experiments to be around 21 kDa. There were 6.3 % uronic acid residues in the VAP. The constituent sugars after TFA hydrolysis were identified by HPLC to include glucose, arabinose, rhamnose, galactose, and xylose in a molar ratio of 405 : 259 : 82 : 42 : 1.

Thermal Design Optimization of the Printed Circuit Board through Area Reduction

The dimensions of an electronic control unit are extremely important in the developing of any new product design. It is well known that a large area of the printed circuit board (PCB) increases thermal performance. For any developed product, when the PCB area is enlarged, the volume, the mass, and the surroundings also increase. This article presents how the shape is more important than the area and the way in which the area of the PCB can be reduced but still has similar or even better thermal performance. An response surface methodology (RSM) of the design of experiments (DOE) quality tool from optimization phase of design for six sigma concept was developed using MINITAB statistical software. The results for each DOE combination of length and width were simulated as a parametric run by the ICEPAK version 19.1 commercial software, which is based on the finite volume method. Numerical analyzes check the obtained transfer function for other dimensions than those analyzed in response surface DOE and it is extrapolated for different areas. With the obtained and numerically checked RSM transfer function, it is recognized a significantly better thermal performance for the same area of the PCB, but with a smaller dimension in the airflow direction.

Exploring the design space of AAV transient-transfection in suspension cell lines.

The safety and utility of adeno-associated virus (AAV) to modulate target gene expression has been well demonstrated, and AAV vectors are a leading gene therapy platform. However, manufacturing presents challenges in terms of productivity and scalability as compared to incumbent therapeutic modalities. In particular, a pivot from adherent cell- to suspension culture-based AAV manufacturing processes requires enhanced study of the transfection step. For the method proposed herein, a Response Surface Design of Experiments is suggested to explore the role of five transfection factors-cell density at transfection, DNA concentration, ratio of complexing reagent to DNA, and molar ratios of the transfecting plasmids-influencing viral genome titer and biological potency. Additionally, an AAV categorical factor matrix is presented for developing a workflow to interrogate the impact of AAV permutations for different capsid serotypes, harbored genes of interest, and inverted terminal repeat configurations on transfection process parameters.

Development of strain-hardening cementitious composites utilizing slag and calcium carbonate powder

Strain-Hardening Cementitious Composites (SHCCs), utilizing slag to replace fly ash and a calcium carbonate powder to replace silica sand, were developed in this study. The underlying motivations were to reduce the variation in SHCC’s mechanical properties caused by the inherent variation in fly ash properties and to investigate the influence of using calcium carbonate powder along with slag on these properties. A response surface design of experiments was used to systematically investigate the effects of the two ingredients – slag and calcium carbonate powder – on the mechanical properties of SHCC and determine the optimum mixture composition. These two ingredients showed significant independent effects as well as interaction effects on the properties of SHCC. The best-performing SHCCs developed in this study exhibited mechanical properties similar to conventional SHCCs but with reduced variability in mechanical properties and improved material sustainability.

OFAT versus DOE as two optimization protocols for the chromatographic analysis of some OTC pharmaceuticals carrying negative cardiovascular effects and administered by pregnant and breast-feeding females: Application to dose dependent effect

AbstractA simple HPLC technique has been utilized for rapid and sensitive quantitative analysis of two mixtures of drugs that are used during pregnancy and lactation. Drugs of the first mixture are used to manage gastrointestinal tract illness that are common during early stages of pregnancy, while pharmaceutical agents of the second mixture are administered over the counter as galactagogues or to overcome postpartum depression. Mixture I includes famotidine (FMT), ranitidine (RNT), nizatidine (NZT), and pantoprazole (PNT), which were separated on a C18 column using a mobile phase composed of methanol: 0.02 M sodium dihydrogen phosphate (60:40, v/v) of pH 6.9, adopting UV detection at 240 nm at a flow rate of 1 mL/min. Mixture II on the other hand, consists of domperidone (DOM), metoclopramide (MET), and sulpiride (SUL). These drugs were eluted using the same column and flow rate as those in mixture I, using a mobile phase consisting of acetonitrile: 0.075 M sodium dihydrogen phosphate (30:70, v/v) of pH 6 adopting a detection wavelength 270 nm. Two optimization protocols were utilized to optimize the chromatographic separation conditions, namely one factor at a time (OFAT) and design of experiments (DOE) where face centered cube response surface experimental design was chosen for this investigation. Comparison of the results obtained from both protocols reveals the accordance between them.Full validation procedure under guidance of United States Pharmacopoeia (USP) was applied to the proposed methods which enabled their application to separate the drugs of both mixtures in spiked rat whole blood samples and in vivo analysis of rat heart blood.

Development of dietary fibre incorporated tuna sausage employing response surface methodology and quality evaluation during chilled storage using multivariate control charts

In the present study, dietary fibre incorporated functional sausage was prepared by optimising the ingredients viz. tuna mince, wheat and oats dietary fibre using response surface methodology. D-optimal mixture response surface experimental design with 13 runs was formulated for the development of dietary fibre incorporated tuna sausage. The optimum combinations of sausage were found to be 62.5% fish mince, 2.5% wheat and 5% oats fibre and 66.8% fish mince and 1.6% of oats and wheat fibre each. The quality evaluation of combination sausage prepared at optimum conditions along with control sample was carried out based on biochemical, physical and sensory parameters during storage in chilled condition at 2°C. Storage stability studies of the optimised sausage samples indicated a shelf life of 14 days under chilled conditions. Multivariate statistical control charts based on T2 and PSE statistics were developed to monitor quality variations during storage.

Development and characterization of edible films based on native cassava starch, beeswax, and propolis

Cassava starch has received research focus due to its low cost, and excellent film-forming ability. However, cassava starch films with relatively strong hydrophilicity greatly limits its application in industries. Therefore, the aim of this study was to develop native cassava starch-based films incorporated with beeswax and ethanolic propolis extract (EPE), to improve the barrier and antimicrobial properties of cassava starch. The films were characterized in terms of physical properties including thickness, moisture content, solubility (water, acidic and alkaline), color, microstructure (FTIR), and water vapor permeability (WVP). The film-forming solutions composed of cassava starch (2-4%w/v), beeswax (0.5–0.9%w/w), and ethanolic propolis extract (1–4%v/v) were prepared according to a three-factor Box-Behnken response surface experimental design. Antifungal activity of films with 4.0 mL of EPE was assessed against Aspergillus niger. The results showed that higher concentrations of beeswax produced films with the lowest WVP and moisture content values. An increase in EPE content reduced the lightness, producing opaque and yellow-colored films. EPE showed antifungal activity against Aspergillus niger. In conclusion, it could be said that cassava starch-based films incorporated with beeswax and propolis have the potential to be used food packaging applications, and coatings for fresh and minimally processed products, mainly in non-acidic fruits and vegetables.

Preclinical optimization of an enterotoxigenic Escherichia coli adjuvanted subunit vaccine using response surface design of experiments

Enterotoxigenic E. coli (ETEC) is a leading cause of moderate-to-severe diarrhoea. ETEC colonizes the intestine through fimbrial tip adhesin colonization factors and produces heat-stable and/or heat-labile (LT) toxins, stimulating fluid and electrolyte release leading to watery diarrhoea. We reported that a vaccine containing recombinant colonization factor antigen (CfaEB) targeting fimbrial tip adhesin of the colonization factor antigen I (CFA/I) and an attenuated LT toxoid (dmLT) elicited mucosal and systemic immune responses against both targets. Additionally, the toll-like receptor 4 ligand second-generation lipid adjuvant (TLR4-SLA) induced a potent mucosal response, dependent on adjuvant formulation. However, a combination of vaccine components at their respective individual optimal doses may not achieve the optimal immune profile. We studied a subunit ETEC vaccine prototype in mice using a response surface design of experiments (DoE), consisting of 64 vaccine dose-combinations of CfaEB, dmLT and SLA in four formulations (aqueous, aluminium oxyhydroxide, squalene-in-water stable nanoemulsion [SE] or liposomes containing the saponin Quillaja saponaria-21 [LSQ]). Nine readouts focusing on antibody functionality and plasma cell response were selected to profile the immune response of parenterally administered ETEC vaccine prototype. The data were integrated in a model to identify the optimal dosage of each vaccine component and best formulation. Compared to maximal doses used in mouse models (10 µg CfaEB, 1 µg dmLT and 5 µg SLA), a reduction in the vaccine components up to 37%, 60% and 88% for CfaEB, dmLT and SLA, respectively, maintained or even maximized immune responses, with SE and LSQ the best formulations. The DoE approach can help determine the best vaccine composition with a limited number of experiments and may accelerate development of multi-antigen/component ETEC vaccines.

Species Identity and Initial Size Rather Than Neighborhood Interactions Influence Survival in a Response-Surface Examination of Competition.

To measure intraspecific and interspecific interaction coefficients among tree species is the key to explore the underlying mechanisms for species coexistence and biodiversity maintenance in forests. Through the response surface experimental design, we established a long-term field experiment by planting 27,300 seedlings of four tree species (Erythrophleum fordii, Pinus massoniana, Castanopsis fissa, and Castanopsis carlesii) in 504 plots in different species combinations (six pairwise combinations of four species), abundance proportions (five abundance proportions of two species, i.e. A: B = 1:0, 3:1, 1:1, 1:3, 0:1), and stand densities (25, 36, 64, and 100 seedlings per plot). In this initial report, we aimed to quantify the relative importance of biotic and abiotic factors on seedling survival at the early stage of growth, which is a critical period for seedling establishment. We found that plot-level seedling survival rate was determined by species combination and their abundance proportion rather than stand density. At the individual level, individual survival probability was mainly explained by species identity, initial seedling size, and soil conditions rather than neighborhood competition. Our study highlights that the seedling intrinsic properties may be the key factors in determining seedling survival rate, while neighborhood effects were not yet prominent at the seedling life stage.

Optimal design of the gear transmission system based on the modal response surface method

In order to conduct the lightweight optimization design of the gear transmission system, this paper uses the experimental design response surface method to construct the modal response explicit function of the gear transmission system based on the modal analysis results. Furthermore, the optimized design model of the gear transmission system (including gears, gear shafts, and bearings) is established on the base of the results of the modal response surface, and the optimized design model is solved and optimized through the Fmincon toolbox of MATLAB. By comparing the optimized results, it is shown that the optimization design method proposed in this paper can achieve the optimal design of the gear transmission system, which is of great significance to the optimization design of mechanical engineering.

Optimization and prediction of volume shrinkage and warpage of injection-molded thin-walled parts based on neural network

Warpage and volume shrinkage are important indicators of the quality of thin-walled parts during injection molding. In this study, the optimization goals are warpage and volume shrinkage. Design parameters include mold temperature, melt temperature, injection time, holding time, cooling time, and holding pressure. Based on the orthogonal experimental design and response surface experimental design, the MoldFlow software is applied to the simulation of the thin-walled part injection molding process. The importance of various parameters on warpage and volume shrinkage was analyzed by using analysis of variance. Based on the simulation results, a two-layer hidden-layer back propagation (BP) neural network model is established and the genetic algorithm (GA) is used to optimize the weights and thresholds of the back propagation neural network (BPNN) model to reduce warpage and volume shrinkage by optimizing the design parameters significantly. A support vector machine (SVM) combined with GA-BP was used to build a prediction model for predicting warpage and volume shrinkage. Taking the automobile wire harness protection frame as an example, and verified by numerical simulation, the GA-optimized two-layer hidden-layer BP neural network combination method is an effective method for injection molding to reduce warpage and volume shrinkage of thin-walled parts. SVM-BP-GA can accurately provide predictions for optimization goals; the amount of warpage and the volume shrinkage were 0.93% and 1.9%, respectively.