Response Surface Plots Research Articles

Enhanced conditions for anthocyanin extraction from blackberry pomace under ultrasound irradiation

AbstractThe recovery of bioactive compounds from agro‐industrial residues with green solvents in ultrasound‐assisted extraction (UAE) processes represents an interesting alternative from environmental and economical perspectives. Here we investigated optimal conditions to improve the extraction of anthocyanins from blackberry pomace. The experimental data were fitted to the second‐order polynomial model to obtain the regression coefficients, and three‐dimensional (3‐D) response surface plots were considered to represent the relationships between each variable on the response of total monomeric anthocyanin (TMA) content. The ultrasound‐assisted process at an ultrasound amplitude of 40% for 10 min and a concentration of 25 mg/L resulted in the maximum TMA concentration of 1.39 ± 0.02 mgCy3GlE/g. At these extraction conditions, the extract presented total polyphenol and flavonoid contents of 44.12 ± 0.17 mgGAE/g and 63.25 ± 0.53 mgQE/g, respectively. A total of 31 individual compounds, including anthocyanins, flavonols, and phenolic acids, were identified in the extract. Concentrations of cyanidin‐3‐glucoside and caffeic, gallic, and ellagic acids were 2.38 ± 0.09, 0.47 ± 0.01, 0.55 ± 0.01, and 0.48 ± 0.01 mg/g, respectively. Compared to the conventional extraction, the UAE represented an increase of 20.87% in total anthocyanins. Thus, the UAE at suitable conditions is suggested to recover bioactive compounds from blackberry pomace.Practical ApplicationsThe use of blackberry pomace to extract bioactive compounds is promising because it uses a by‐product from the fruit processing industry. This study presents an innovative proposal of optimal process conditions to recover anthocyanins from blackberry pomace under ultrasound irradiation. The use of green solvents, as water, in ultrasound‐assisted extraction (UAE) processes, represents an interesting alternative from environmental and economical perspectives, UAE process is a favorable, fast, efficient, and environmentally friendly method. The obtained blackberry pomace powder is an interesting ingredient to food and pharmaceutical industries, mainly due to the elevated concentration of added‐value compounds. Besides the high amount of anthocyanins content, which could be used as a dye and as antioxidant compounds in several types of food.

Modeling and optimization of friction stir stitching of AISI 201 stainless steel via Box-Behnken design methodology

Abstract The paper investigates the modelling and optimization of the notch-repaired/friction stir stitched AISI 201 stainless steel welds via the use of a non-consumable tool-based repair process. The repair process employs a sequential hopping-stitching approach. This approach involves the application of two intercepted and completely overlapped plunging actions of a probe-less titanium carbide tool to create an effective refilling and repair of the notched zone. Box-Behnken design (BBD) was employed for the experimental planning, modelling, and optimization of the notch-repair process. Tool rotational speed, penetration depth and dwell time of the tool were the studied process parameters while tensile strength was the response variable. A quadratic model was identified as the best model for the notch-repaired welds based on the combination of a low sequential P-value of 0.008216, a high lack of fit P-value of 0.931366, and a close to unity adjusted and predicted R-square values. The process parameter and their interaction effects on the tensile strength of the repaired notch were identified via the ANOVA analysis. Plunge depth (main effect) and interaction effect of tool rotational speed and dwell time had significant influences on the notch-repair process and the resultant tensile strength of the AISI 201 stainless steel. The visual representations of these effects were shown through the 2D elliptical contour and 3D response surface plots. The optimized process parameters were identified as 1215.9795 rpm, 0.40262212 mm, and 5.98706376 s while the resultant notch-repaired joint yielded a tensile strength of 886 MPa, which is close to the predicted value.

Response surface methodology for the optimization of CO2 uptake using waste concrete powder

The novelty of this study is to find out the CO2 uptake of waste concrete powder (WCP) derived from construction and demolition (C&D) waste recycling plant. The CO2 uptake of WCP was determined by the response surface methodology (RSM) considering the influence of carbonation time (t) and water-to-solid (w/s) ratio so as to realize the optimal condition to maximize the CO2 uptake via mineral carbonation of WCP. A regression model was developed and validated with experiments for the optimization of CO2 uptake. The response surface plot and analysis of variance show that increase in carbonation time increased the WCP CO2 uptake irrespective of w/s ratios. At carbonation time of 90 h and 0.4 w/s ratio, the optimum CO2 uptake was 2.81% considering the carbonation and energy efficiencies. The physio-chemical changes in WCP after carbonation were characterized together with heavy metal leaching performance. The blended cement mortar with carbonated WCP has a strength activity index of more than 75, which proves the feasibility of applying WCP as supplementary cementitious material for CO2 sequestration.

Adsorption of CdII by synthetic zeolite under multi-factor using response surface methodology

The remediation of heavy metal contamination was urgent owing to their toxicity and non-biodegradability. In this study, a synthetic zeolite originated from natural low-grade molybdenum ore (NMO) was used to adsorb CdII from wastewater under simulated multi-environmental factors. X-ray diffraction spectroscopy proved that faujasite was successfully synthesized. The specific surface area of the synthetic zeolite was up to 652.3 m2/g, based on the nitrogen adsorption and desorption isotherms. X-ray photoelectron spectroscopy confirmed that ion-exchange was a major mechanism of CdII adsorption. Batch adsorption experiments showed that synthetic zeolite has an excellent adsorption capacity for CdII at pH above 4. The theoretical maximum adsorption capacity was 249.63 mg/kg, as evidenced by the adsorption model fitting. Systematic adsorption experiments showed that the quadratic regression model can be used to predict the CdII adsorption amount of synthetic zeolite (predicted r² = 0.9027) under six environmental factors. The fitted results showed a decreasing influence on adsorption capacity in the following order: CdII concentration > adsorbent dosage > CaII concentration > NaI concentration > pH > Temperature. In all, the synthetic zeolite has a great potential for treating CdII-containing wastewater. Especially the application could be optimized with the predicted adsorption based on the response surface plots.

The optimization of welding hardfacing on wear resistance of FC-25 grey cast iron steel substrate by response surface methodology (RSM)

This paper aimed to identify the optimal conditions for welding hardfacing by applying the Response Surface Methodology (RSM). The welding heat input, electrode type, and hardfacing layer on wear resistance of welding hardfacing were all optimized using the Box-Behnken experimental design. The findings revealed that these three variables had an impact on the volume loss of welding hardfacing. Because of the high coefficient of determination, the experimental data obtained were to a quadratic equation (96.90%). The ideal condition was determined using a 3D response surface plot and a contour map produced from mathematical models. The following were the ideal welding conditions: With a welding heat input of 1.58 J, a filler metal type of DFA2-600-B, and a third layer of hardfacing, the lower volume loss of the weld was 1.29 mm3.

Low-Velocity Impact and Compression after Impact Properties of Hemp and Jute Fiber Reinforced Epoxy Composites

ABSTRACT This paper presents an experimental study on the low-velocity impact behavior of hemp and jute fiber-reinforced epoxy composite. The Compressive After Impact (CAI) properties of composites post-impact are used for analysis. The type of damage and area of damage is used to analyze the effectiveness of composites for variation in impact energy. The impacted composite specimens were subjected to Compression After the Impact (CAI) test. A two-factor, five-level Central Composite Design (CCD) model of response surface methodology (RSM) is used to analyze the effect of input variables on ultimate load and thereby obtain the optimized input conditions for damage. The experimental results were optimized using Derringer’s Desirability function. The results indicate that jute laminates show a better impact energy absorption capability than hemp laminate composites. From the study, it was observed that the CAI strength of jute/epoxy composite was high compared to hemp/epoxy composite and the jute/epoxy composite exhibited enhanced CAI properties of the composite. From the regression equations and the three-dimensional response surface plots obtained from CCD, optimized ramp values were obtained. The optimized ultimate load of hemp and jute fiber laminate was 5.90 MPa and 10.68 MPa, respectively.

Isolation and optimization of extracellular PHB depolymerase producer Aeromonas caviae Kuk1-(34) for sustainable solid waste management of biodegradable polymers

Bioplastics, synthesized by several microbes, accumulates inside cells under stress conditions as a storage material. Several microbial enzymes play a crucial role in their degradation. This research was carried to test the biodegradability of poly-β-hydroxybutyrate (PHB) utilizing PHB depolymerase, produced by bacteria isolated from sewage waste soil samples. Potent PHB degrader was screened based on the highest zone of hydrolysis followed by PHB depolymerase activity. Soil burial method was employed to check their degradation ability at different incubation periods of 15, 30, and 45 days at 37±2°C, pH 7.0 at 60% moisture with 1% microbial inoculum of Aeromonas caviae Kuk1-(34) (MN414252). Without optimized conditions, 85.76% of the total weight of the PHB film was degraded after 45 days. This degradation was confirmed with Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscope (SEM) analysis. The presence of bacterial colonies on the surface of the degraded film, along with crest, holes, surface erosion, and roughness, were visible. Media optimization was carried out in statistical mode using Plackett Burman (PB) and Central Composite Design (CCD) of Response Surface Methodology (RSM) by considering ten different factors. Analysis of Variance (ANOVA), Pareto chart, response surface plots, and F-value of 3.82 implies that the above statistical model was significant. The best production of PHB depolymerase enzyme (14.98 U/mL) was observed when strain Kuk1-(34) was grown in a media containing 0.1% PHB, K2HPO4 (1.6 gm/L) at 27 ℃ for seven days. Exploiting these statistically optimized conditions, the culture was found to be a suitable candidate for the management of solid waste, where 94.4% of the total weight of the PHB film was degraded after 45 days of incubation.

Artificial Neural Network Modeling of Abrasion Loss and Surface Roughness of Crab Carapace Impregnated Coir Vinyl Ester Composites

Roughness plays an important role in determining how an object would be related with its environment. In tribology, rough surfaces easily obtain wear more quickly and have higher friction coefficients than smooth surfaces. Roughness is often a good analyzer of the performance of a mechanical component. This investigation is aimed to study the abrasion loss and surface roughness behaviors in crab carapace-filled coir fiber reinforced vinyl ester composites. The development of filler-impregnated fiber-polymer composites in recent years necessitated the evaluation and prediction of tribological behaviors in fiber reinforced composites. The composite fabrication was planned by varying the three fabrication parameters with three levels such as fiber length (10 mm, 30 mm, and 50 mm), fiber diameter (0.1 mm, 0.18 mm, and 0.25 mm), and content of crab carapace fillers (0%, 2%, and 4%) as per Design of Experiments (DOEs) in this current investigation. Low velocity integrated wear loss tests on composite samples were carried out, and also the average surface roughness is measured in the fabricated composites. Nonlinear regression equations were developed to study the correlation between tribological behaviors and fabrication parameters. The interaction effect of fabrication parameters was studied using ANOVA two-tail test and validated using response surface plots. In order to forecast abrasion loss and surface roughness behaviors, artificial neural network (ANN) models were constructed, and it was discovered that the produced ANN models effectively predicted the abrasion loss as well as surface roughness behavior within the given ranges.

Optimization Extraction and Antioxidant Activity of Crude Polysaccharide from Chestnut Mushroom (Agrocybe aegerita) by Accelerated Solvent Extraction Combined with Response Surface Methodology (ASE-RSM).

The present work is conducted to investigate the optimal extraction technology of polysaccharide from chestnut mushroom (Agrocybe aegerita) using a new method based on accelerated solvent extraction combined with response surface methodology (ASE-RSM). The conventional reflux extraction (CRE) method and ultrasonic-assisted extraction (UAE) method were also carried out. Additionally, the in vitro antioxidant activities, including ABTS and DPPH assay, were evaluated. The RSM method, based on a three level and three variable Box–Behnken design (BBD), was developed to obtain the optimal combination of extraction conditions. In brief, the polysaccharide was optimally extracted with water as extraction solvent, extraction temperature of 71 °C, extraction time of 6.5 min, number of cycles of 3, and extraction pressure of 10 MPa. The 3D response surface plot and the contour plot derived from the mathematical models were applied to determine the optimal conditions. Under the above conditions, the experimental value of polysaccharide yield was 19.77 ± 0.12%, which is in close agreement with the value (19.81%) predicted by the model. These findings demonstrate that ASE-RSM produce much higher polysaccharide and consumed environmentally friendly extraction and solvent systems, have less extraction discrimination and shorter time and provide scientific basis for industrialization of polysaccharide extraction. Moreover, it was proved that the polysaccharide had the potential ability to scavenge ABTS and DPPH.

Maraviroc Oral Disintegration Tablet: Analytical Design of Experiments (DoE) for Assessment and Comparison of In vitro Dissolution Profiles

Background: The bioavailability of a drug in a solid oral dose depends on its release from the drug product and its balance in dissolution. Compared with a reference drug, the newly developed formulation needs to establish bioequivalence by comparing the dissolution profile. Objective: To compare dissolution profiles of a newly developed maraviroc oral disintegration tablet and the reference Axentri® tablet. The current research was designed to establish and validate an integral analytical consistency by Quality by Design (QbD) approach to quantify maraviroc from dissolution samples using the RP-HPLC method. Methods: Maraviroc was formulated into an orally disintegrating tablet using a direct compression technique at different concentrations of sodium starch glycolate as super disintegrants and talc and magnesium stearate as glidants. The dissolution test in 0.1N HCl was performed according to standard procedures to predict bioequivalence. The results of dissolution tests were analyzed using the QbD Box Behnken Design multivariate RP-HPLC method. Results: The optimized formulation (F2) was selected as it showed 90% drug release in 5 min and a disintegration time of 22 sec with dissolution profiles to the marketed reference to meet the FDA requirements of f2 similarity factor statistics. The integrated analytical QbD method was statistically analyzed by ANOVA, counter-plot, and 3D response surface plots, which demonstrated that the model is statistically significant. The developed method was validated as per ICH guidelines Q2 (R1). Conclusion : In conclusion, maraviroc oral disintegrating tablets have been well prepared, and superior statement consistency is established by the implementation of the QbD analytical method for orally disintegrating tablet excellence and adoption.

Quality by Design Enabled Development and Optimization of the Nanoparticulate System of Cabazitaxel

Cabazitaxel (CTX), a novel taxane derivative, has proven effective in many solid tumors. It is also approved in many countries for multiple uses in solid tumors. The current marketed formulation lacks the tumortargeting ability, and its uneven distribution in the body causes toxicity to normal tissues. Further, it is a surfactant (polysorbate 80) based micellar formulation composed of ethanol as a co-solvent to improve the solubility of CTX, which causes severe and life-threatening side effects. Hence, to avoid the problem associated with this conventional CTX formulation, the nanoparticulate drug delivery system of CTX was developed by employing the Quality by Design (QbD) approach. The CTX nanoparticulate system was developed by employing a bottom-up followed by a top-down approach. The size reduction was obtained by High-Pressure Homogenizer (HPH). The formulation optimization was done using QbD approach. Design of experiments (DoE) was used to understand the effect of various formulation and process variables on a dependent variable like particle size distribution. The stabilizer concentration, concentration of solubilizer, HPH pressure, and passes were selected as independent factors while particle size distribution was selected as a dependent factor for evaluation. The nanoparticulate system was developed using PEG-400 as solubilizing agents, while Soya Phosphatidylcholine (SPC) was used as a surface stabilizer. Response surface plots revealed a decrease in particle size with increasing concentration of SPC and PEG 400. Similarly, a decrease in particle size with increased HPH passes and pressure was found. The optimum concentrations of SPC and PEG 400 were found to be 20% and 2.5%, respectively. 20 KPSI pressure and 5 HPH passes were derived as optimized processing parameters from DoE. The optimized formulation had a size of 43.5 nm, with PDI is less than 0.4. Due to its narrow particle size distribution, the formulation did not show any increase in particle size or aggregation up to 24 hours. The present research confirms the feasibility of developing the nanoparticulate system of CTX using the bottom-up followed by the top-down technique. The formulation was systematically optimized using QbD approach. The optimum concentration of PEG 400 as solubilizer and concentration of SPC as stabilizer was obtained from DoE, yielding optimum particle size and stability

Experimental Study on Lateral Resolution of Phased Array Ultrasonic Testing of Irregular Structure Weld Defects

Irregular structure welds are used in numerous military industries. This paper is interested in how to utilize phased array ultrasonic testing (PAUT) to identify and locate irregular structure weld defects. In this paper, CIVA simulation results were compared with inspection results of known defects and were found to be in very good agreement. This shows the feasibility of CIVA simulations. The coupling, among process parameters, affects the amplitude drop value from the peak to the trough of defects signal response, which represents the lateral resolution of internal weld defects and affect the imaging quality directly. Thus, the proper setting of detection parameters is critical to improve the testing efficiency and the imaging quality. This paper uses the response surface methodology (RSM) to design the test and conduct a factorial test to analyze the effect of each parameter. Modelling of the parameters and the response is conducted through center composite design (CCD) to analyze the coupling among multiple parameters and the reliability of the model. In the process of PAUT, the response surface plot, contour plot and the initial design domain of process parameters were combined for weld defects to determine the optimal parameters rapidly and correctly. Besides, CIVA simulation could further verify optimized detection parameters and position in industry site. Finally, irregular structure weld defects were identified accurately with PAUT imaging.

FUNDAMENTAL CONCEPTS AND RECENT APPLICATIONS OF FACTORIAL STATISTICAL DESIGNS

Factorial designs have been increasingly used in scientific investigations and technological development. The designs, through the use of matrices with all the treatment combinations, have been capable to effectively characterize the relationships between the variables of multi-factor experiments, assess the experimental variabilities, and derive mathematical functions that represent the behavior of the responses. Factorial designs were fractionalized, which substantially reduced the number of treatments without the loss of relevant information. The addition of central and star points to the factorial arrays has given them the orthogonality and rotatability characteristics, frequently used to fit models with curvature and identify critical regions of interest. Literature reports indicated that factorial designs, also called factorial experiments, were successfully applied in different types of investigations, including in cost evaluations and time-series studies. They were capable to estimate important features of the experiments, like the individual and combined effects of factors, the magnitude of residuals, additionally to express the relationships of the variables in polynomial equations, draw response surface and contour plots, and determine optimal combinations of parameters. In this review, the fundamental aspects of the Complete, Fractional, Central Composite Rotational and Asymmetrical factorial designs were conceptualized, and recent applications of these powerful tools were described.

A systematic study of the production of Monacolin K by solid state fermentation of Monascus ruber

Monacolin K is one of the bioactive substances produced by Monascus ruber during fermentation. The multi-factors and their interactions on the effect of solid-state fermentation of Monascus for high yield of monacolin K were attractive to industrial production. A detailed study of 7 single-factor experiments and a series of experiments with Plackette-Burman and Box-Benhnken design, data fitting and modeling, and analyzing the visual 3D response surface plots for investigation of the key factors for Monacolin K production. The results showed that initial moisture (50 ~ 55%) and bran content (4.5 ~ 5.5%) as the key factors of transport for nutrients and oxygen during the solid-state fermentation (SSF) process of Monascus. Under the optimal conditions, a temperature shifting of the SSF with a higher Monacolin K yield of 14.53 ± 0.16 mg·g− 1 compared with the content of monacolin K in the commercially available functional red yeast rice of 8 mg g− 1.

The Application of the Box-Behnken Design Response Surface Methodology to Study Optimized Formulation Variables on the Drug Release Pattern of Benidipine Hydrochloride Extended-release Matrix Tablet

Background: In this research study, an attempt has been made using Box-Behnken de-sign (BBD) Response Surface Methodology to find optimized formulation variables at 3 levels (low, medium, and high) to affect the dependent response, which is the % drug release pattern at different time intervals in extending drug release of Benidipine Hydrochloride(BH) matrix tablets. BH extended-release tablets reduce the side effects of multiple dosing used during conventional tab-lets. Methods: As in the preliminary work, we have found the most profound formulation factors for ex-tending drug release of BH matrix tablets are Eudragit RS 100 amount (X1), HPMC K 100 M (X2), chitosan amount (X3), which we selected as independent factors at their low and high levels for this study considering % drug release at three different time intervals i.e., R1 (% of drug release in 2 hours), R2 (% of drug release in 15 hours) and R3 (% of drug release in 18 hours) as dependent variables using a dissolution media of phosphate buffer pH of 6.8 with 75rpm. Results: From the experimental runs of prepared tablets as predicted by the Design-Expert software, the model shows a quadratic equation due to less p-value, and a very less difference was observed between adjusted R2 and predicted values R2 in all selected responses, which we considered as the % drug release. Conclusion: Therefore, by using the graphical response surface plot of BBD software, the opti-mized formulation of BH extended-release tablet of Eudragit RS 100, HPMC K 100 M, and Chi-tosan containing an amount of 45mg, 105 mg, and 45.71 mg, respectively shows an extended drug release of more than 18 hours. To construct a satisfying fit of the model for the optimized formula-tion, a result analysis was carried out for the internally studentized residuals versus the experimental runs indicating all data points were placed within limits, and the values of the predicted and actual response of each run were normally distributed near a straight line.

Optimization of Valine Production Using Bacillus Cereus Isolated from Soil

The Production of amino acids such as valine by fermentation has become an essential technology of Industrial microbiology. Valine has extensive industrial applications, which is used as intermediate for the synthesis of agricultural pesticides and semi-synthetic veterinary antibiotics. This research work was aimed to isolate Bacillus cereus from the soil capable of valine production and optimize the condition for maximum yield. The valine production was optimized initially by one factor at a time (OFAT) and response surface methodology (RSM). Optimum valine yield (3.53mg/ml) was obtained at pH 7.5, temperature of 40℃ incubation time of 58hrs and 125rpm agitation rate, the response surface plots (3D and contour) revealed a significant interactions between pH, temperature and incubation time to valine yield. The results of the characterized valine produced using Bacillus cereus shows similar properties with the commercially produced valine by using Fourier transform infrared spectroscopy (FTIR) and boiling point. Based on the study, the isolated Bacillus cereus could have a potential for industrial production of valine under optimized conditions.

Response surface optimization of enzymatic hydrolysis and ROS scavenging activity of silk sericin hydrolysates

Context Sericin, a protein found in wastewater from the silk industry, was shown to contain a variety of biological activities, including antioxidant. The enzymatic conditions have been continuously modified to improve antioxidant effect and scavenging capacity against various free radicals of silk sericin protein. Objective Variables in enzymatic reactions, including pH, temperature and enzyme/substrate ratio were analysed to discover the optimum conditions for antioxidant activity of sericin hydrolysates. Materials and methods Hydrolysis reaction catalysed by Alcalase® was optimized through response surface methodology (RSM) in order to generate sericin hydrolysates possessing potency for % inhibition on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, ferric-reducing power and peroxyl scavenging capacity. Flow cytometry was performed to evaluate cellular ROS level in human HaCaT keratinocytes and melanin-generating MNT1 cells pre-treated either with 20 mg/mL RSM-optimized sericin hydrolysates or 5 mM N-acetyl cysteine (NAC) for 60 min prior exposure with 1 mM hydrogen peroxide (H2O2). Results Among these three variables, response surface plots demonstrate the major role of temperature on scavenging capacity of sericin hydrolysates. Sericin hydrolysates prepared by using Alcalase® at RSM-optimized condition (enzyme/substrate ratio: 1.5, pH: 7.5, temperature: 70 °C) possessed % inhibition against H2O2 at 99.11 ± 0.54% and 73.25 ± 8.32% in HaCaT and MNT1 cells, respectively, while pre-treatment with NAC indicated the % inhibition only at 30.26 ± 7.62% in HaCaT and 51.05 ± 7.14% in MNT1 cells. Discussion and conclusions The acquired RSM information would be of benefit for further developing antioxidant peptide from diverse resources, especially the recycling of waste products from silk industry.

Optimizing PET Glycolysis with an Oyster Shell-Derived Catalyst Using Response Surface Methodology.

Polyethylene terephthalate (PET) waste was depolymerized into bis(2-hydroxyethyl) terephthalate (BHET) through glycolysis with the aid of oyster shell-derived catalysts. The equilibrium yield of BHET was as high as 68.6% under the reaction conditions of mass ratios (EG to PET = 5, catalyst to PET = 0.01) at 195 °C for 1 h. Although biomass-derived Ca-based catalysts were used for PET glycolysis to obtain BHET monomers, no statistical analysis was performed to optimize the reaction conditions. Thus, in this study, we applied response surface methodology (RSM) based on three-factor Box–Behnken design (BBD) to investigate the optimal conditions for glycolysis by analyzing the independent and interactive effects of the factors, respectively. Three independent factors of interest include reaction time, temperature, and mass ratio of catalyst to PET under a fixed amount of ethylene glycol (mass ratio of EG to PET = 5) due to the saturation of the yield above the mass ratio. The quadratic regression equation was calculated for predicting the yield of BHET, which was in good agreement with the experimental data (R2 = 0.989). The contour and response surface plots showed the interaction effect between three variables and the BHET yield with the maximum average yield of monomer (64.98%) under reaction conditions of 1 wt% of mass ratio (catalyst to PET), 195 °C, and 45 min. Both the experimental results and the analyses of the response surfaces revealed that the interaction effects of reaction temperature vs. time and temperature vs. mass ratio of the catalyst to the PET were more prominent in comparison to reaction time vs. mass ratio of the catalyst to the PET.

Structural Analysis and Optimization of Heavy Vehicle Chassis Using Aluminium P100/6061 Al and Al GA 7-230 MMC

A chassis is one of the vital parts of a heavy motor vehicle, which provides rigidity to the vehicle and improves structural stability and rigidity for accurate handling. The design and material of a chassis structure significantly affects its strength and weight. Optimization techniques can be used in systematic design improvement of chassis to meet industry requirements. The current research is intended to optimize the design of chassis using the Box–Behnken design scheme and the material tested is P100/6061 Al and Al GA 7-230 MMC. Different design points were generated using the design of the experiments. Equivalent stress, deformation and mass were evaluated for each design point. The variable selected for optimization using the Box–Behnken scheme was cross member width. The CAD modelling and FE simulation of the heavy motor vehicle chassis were conducted using ANSYS software. From the optimization conducted on the chassis design, response surface plots of equivalent stress, deformation and mass were generated, which enabled to determine the range of dimensions for which these parameters are maximum or minimum. The sensitivity plots of different variables were generated, which has shown that cross member 2’s width has a maximum effect on equivalent stress and cross member 3’s width has a minimum effect on equivalent stress, whereas for total deformation, cross member 3 shows the maximum sensitivity percentage, which signifies that cross member 3 has the maximum effect on total deformation, and vice versa. The use of the aluminium metal matrix composites P100/6061 Al and Al GA 7-230 MMC aided to reduce the weight of the chassis by 68% and 70%, respectively, without much reduction in the strength of the chassis.

Self-assembling of 3D layered flower architecture of BiOI modified MgCr2O4 nanosphere for wider spectrum visible-light photocatalytic degradation of rhodamine B and malachite green: Mechanism, pathway, reactive sites and toxicity prediction

In this study, 3D BiOI nanoparticle (BOI NPs) modified MgCr2O4 nanoparticle (MCO NPs) was fabricated by simple sonochemical and coprecipitation method for the enhanced photocatalytic activity. The morphological structure of the MgCr2O4–BiOI nanocomposite (MCO-BOI NCs) was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–visible diffuse reflectance spectroscopy (DRS), electron impedance spectroscopy (EIS) and photo luminescence (PL). The lower in the PL intensity and small arc in EIS for NCs shows the effective charge separation and lower in rate of recombination of charge carriers in NCs than the pure MCO and BOI NPs. The degradation efficiency of Rhodamine B (RhB) and malachite green (MG) by MCO-BOI NCs was found to be 99.5% and 98.2% receptivity. In addition, the photocatalytic degradation of RhB and MG was studied under various environmental parameters (different pH, varying the concentration of NCs and dyes) and response surface (RSM) plot was performed. The complete mineralization of RhB and MG by MCO-BOI NCs was determined by TOC. In addition, the photocatalytic degradation pathway was elucidated based on GC-MS results and Fukui function. In addition, the toxicity of intermediate formed during the degradation of RhB and MG was predicted by ECOSAR. The present work highlights the application of MCO-BOI NCs in environmental remediation for toxic pollutant removal.