Response Surface Central Composite Design Research Articles

Superior decomposition of xenobiotic RB5 dye using three-dimensional electrochemical treatment: Response surface methodology modelling, artificial intelligence, and machine learning-based optimisation approaches

The highly efficient electrochemical treatment technology for dye-polluted wastewater is one of hot research topics in industrial wastewater treatment. This study reported a three-dimensional electrochemical treatment process integrating graphite intercalation compound (GIC) adsorption, direct anodic oxidation, and ∙OH oxidation for decolourising Reactive Black 5 (RB5) from aqueous solutions. The electrochemical process was optimised using the novel progressive central composite design–response surface methodology (CCD–NPRSM), hybrid artificial neural network–extreme gradient boosting (hybrid ANN–XGBoost), and classification and regression trees (CART). CCD–NPRSM and hybrid ANN–XGBoost were employed to minimise errors in evaluating the electrochemical process involving three manipulated operational parameters: current density, electrolysis (treatment) time, and initial dye concentration. The optimised decolourisation efficiencies were 99.30%, 96.63%, and 99.14% for CCD–NPRSM, hybrid ANN–XGBoost, and CART, respectively, compared to the 98.46% RB5 removal rate observed experimentally under optimum conditions: approximately 20 mA/cm2 of current density, 20 min of electrolysis time, and 65 mg/L of RB5. The optimised mineralisation efficiencies ranged between 89% and 92% for different models based on total organic carbon (TOC). Experimental studies confirmed that the predictive efficiency of optimised models ranked in the descending order of hybrid ANN–XGBoost, CCD–NPRSM, and CART. Model validation using analysis of variance (ANOVA) revealed that hybrid ANN–XGBoost had a mean square error (MSE) and a coefficient of determination (R2) of approximately 0.014 and 0.998 respectively, for the RB5 removal efficiency, outperforming CCD–NPRSM with MSE and R2 of 0.518 and 0.998, respectively. Overall, the hybrid ANN–XGBoost approach is the most feasible technique for assessing the electrochemical treatment efficiency in RB5 dye wastewater decolourisation.

Urinary biomonitoring of fuel ether oxygenates using a needle trap device packed with a novel molecularly imprinted polymer surface modified Zeolite Y

This study introduces an innovative needle trap device (NTD) featuring a molecularly imprinted polymer (MIP) surface-modified Zeolite Y. The developed NTD was integrated with gas chromatography-flame ionization detector (GC-FID) and employed for analysis of fuel ether oxygenates (methyl tert‑butyl ether, MTBE, ethyl tert‑butyl ether, ETBE, and tert‑butyl formate, TBF) in urine samples. To optimize the key experimental variables including extraction temperature, extraction time, salt concentration, and stirring speed, a central composite design-response surface methodology (CCD-RSM) was employed. The optimal values for extraction in the study were found to be 51.2 °C extraction temperature, 46.2 min extraction time, 27 % salt concentration, and 620 rpm stirring speed. Under the optimized conditions, the calibration curves demonstrated excellent linearity within the range of 0.1–100 μg L−1, with correlation coefficients (R2) exceeding 0.99. The limits of detection (LODs) for MTBE, ETBE, and TBF were obtained 0.06, 0.08, and 0.09 μg L−1, respectively. Moreover, the limits of quantification (LOQs) for MTBE, ETBE, and TBF were obtained 0.18, 0.24, and 0.27 μg L−1, respectively. The enrichment factor was also found to be in the range of 98–129.The NTD-GC-FID procedure demonstrated a high extraction efficiency, making it a promising tool for urinary biomonitoring of fuel ether oxygenates with improved sensitivity and selectivity compared to current methods.

Selection of performance indicators on dielectric strength and viscosity for chlorinated polyvinyl chloride with N-Methyl-2-pyrrolidone: Optimization using central composite design-response surface methodology

N-methyl-2-pyrrolidone is a highly polar aprotic solvent that is frequently utilized across a broad range of applications in industry. The composition of chlorinated polyvinyl chloride is commonly flame-resistant and mechanically strong. In this research, the central composite design technique uses response surface methodology to perform a parametric study. The effect of the input variables wt.% (16%, 20%, 24%), stirring speed (300, 600, 900 r/min), and stirring time (20 min, 30 min, 40 min) on the output responses (dielectric strength kV/mm, and viscosity Pascal) were examined. The output responses were recorded during the experiments according to the experimental design. The factors impacting the response were identified through analysis of variance. According to the predicted vs. actual diagram, the confirmed experiments fit well with the predictions. Based on the response surface, the parameter interaction profile was analyzed. According to the contour plots related to each interaction, the maximum value can be achieved within different stirring parameters. Based on the result of optimization, the optimum values of dielectric strength and viscosity were found in (wt.% of chlorinated polyvinyl chloride—18.101%), (stirring speed—664 r/min), (stirring time—21.860 min). The output response obtained from the response surface methodology is the dielectric strength (18.5 kV/mm) and viscosity (37.67 Pa).

Impacts of synthesis variables on spectroscopics evaluation of biobased fatty amide as alkylammonium salt’s precursor for perovskite

Ammonium salts are widely used in chemical industries as additives in cement industries, phase change materials in thermal cooling, ionic materials in electrochromic window and multifunction medium/precursor/catalyst in solar cells to improve the efficiency and stability. This work introduces a procedural enhancement by incorporating a liquid-liquid extraction purification process, resulting in a high-purity biobased fatty amide (FA) with tri-substitution and high-purity biobased tetraalkylammonium ammonium salt (TAS). Biobased FA derived from renewable sources was synthesized via an amidation reaction between fatty acids from vegetable oil with tris(3-aminopropyl)amine under reflux conditions, producing a precursor for TAS used in perovskite solar cell (PSC). This study aimed to optimize and determine the reaction condition of biobased FA at various key synthesis variables by investigating the effects of solvent selection, reaction and crystallization, temperature, catalyst, mole ratio, and dehydrating agent on synthesis yield. A multiple liquid-liquid extraction process was employed to enhance the purity of biobased FA by tunning the selection of solvent based on its relative polarity of the reactant and products. Response surface methodology (RSM) and central composite design (CCD) were utilized to optimize the total yield and the three key variables (reaction time, crystallization time, catalyst amount) respectively. The experimental model developed in this study demonstrated a high degree of fitness with the experimental data (F-value = 27.34), p-value < 0.05) and nonsignificant lack of fit. The model predicted a maximum synthesis yield percentage of 52.62 % under optimal conditions (reaction and crystallization time of 12 and 28 hours), respectively with 4.47 % catalyst). The coefficient of determination of R2 = 0.98 shows a high correlation with the predicted values and in good agreement with the experimental values. Physicochemical properties analysis using spectroscopies techniques, confirmed improved purity with 100% abundance yield of tri-substitution biobased FA and enhanced TAS’s purity up to 60%. The optimization study sheds light on the impact of key synthesis variables on the synthesis yield and percentage abundance (purity), advancing the development of more efficient and tailored sustainable construction materials. These findings highlight the potential of using biobased FA as a sustainable source for TAS production, contributing to a more environmentally friendly approach in PSC development.

Construction of Maize Threshing Model by DEM Simulation

This paper proposes a modeling method of maize in threshing. The static friction coefficient and rolling resistance coefficient of the maize grain were measured using the slope method. The maize grain stacking angle test was designed using the central composite design response surface test. A regression model was established based on the simulation results to find the best combination. The results suggested that the modeling method proposed in this paper was effective in improving the accuracy of maize grain simulation compared with previous methods. Furthermore, this paper presents a method to verify the feasibility and reliability of the maize grain cob discrete element model using the distribution of grain in the granary and the final removal rate as the verification method. The results of the actually simulated threshing test were analyzed using a Wilcoxon signed-rank test, heat map analysis, and the Spearman’s rank correlation coefficient. It was found that the DEM model of maize cob is suitable for simulating the maize threshing process. This can aid in further research on the subject.

Formula Optimization and Product Design Analysis of Nougat with Purple Sweet Potato (Ipomoea batatas L), Cowpea (Vigna unguiculata L.) and Stevia Leaves (Stevia rebaudiana)

This study aims to determine the priority attributes of nougat with purple sweet potato, cowpea, and stevia leaves, optimize the nougat formulation from the organoleptic aspect, and determine the physicochemical characteristics of nougat. The research method used the Kano model and the central composite design (CCD) response surface methodology (RSM). The results of this study indicate that the attributes that influence consumer satisfaction are purple color, block shape, and low-calorie natural sweeteners. The optimum formulations obtained from purple sweet potato, cowpea, and stevia leaves were 20%, 1.5%, and 0.15% (Formula A14). Nougat products produce a moisture content of 6.09%-7.35%, ash content of 0.73%-1.95%, reducing sugar content of 11.50-17.11%, sucrose content of 35.14-49.38%, total color difference of 38.15-85.40; and hardness 0.357835-10.455 N. All formulations comply with SNI 3547.2-2008 (soft candy not jelly).

Exploring the efficacy of Congo Red dye as a corrosion inhibitor for aluminum in HCl solution: An interdisciplinary study with RSM modeling and theoretical simulations

This study investigates Congo Red Textile Dye (CRD) as a corrosion inhibitor for aluminum in a 1.0 mol/L hydrochloric acid solution. Utilizing a comprehensive suite of analytical techniques, including gravimetric analysis, scanning electron microscopy (SEM), ultraviolet–visible spectrophotometry (UV–Vis), Electrochemical Impedance Spectroscopy (EIS), and Potentiodynamic Polarization curves (PDP), we assessed CRD’s adsorption mechanism and its corrosion inhibition effectiveness. Significant corrosion mitigation was observed, with the efficiency of inhibition EI (%) increasing alongside CRD concentration, achieving a maximum efficiency of 87.5 %. This enhancement in EI (%) decreases with rising temperatures, assessed across a range from 298 to 323 K. Response surface methodology (RSM) and central composite design (CCD) were employed for accurate corrosion rates (Vcorr) and EI (%) prediction. Additionally, theoretical analysis was performed using global and local reactivity descriptors along with molecular dynamics (MD) simulations. Theoretical results confirmed the widespread presence of nucleophilic and electrophilic sites, along with a strong affinity for the Al surface, suggesting CRD’s potential for enhancing corrosion resistance. This study proposes a potential pathway for the valorization of Congo Red dye, utilizing concentrations within non-toxic thresholds, thereby aligning with environmental safety and industrial application considerations.

Investigating the Efficiency of Photo-Fenton (UV/H2O2/Fe2+) in Removing the Indomethacin Antibiotic From Aqueous Solutions

Water pollution caused by antibiotics is one of the major challenges in the world today. The current research aims to investigate the effect of the Photo-Fenton process in removing indomethacin antibiotics from aqueous solutions. This experiment-based study was conducted on a laboratory scale and discontinuous manner. The influential variables affecting the removal efficiency of indomethacin include initial antibiotic concentration, pH, time, hydrogen peroxide concentration, and iron ion. The study was conducted base on standard methods (APHA, AWWA, CFWP, 2005). The Design Expert software was used to analyze the effect of independent variables on the removal efficiency of indomethacin antibiotics in the Photo-Fenton process (UV/H2O2/Fe2+) using response surface methodology (RSM) and central composite design (CCD). To ensure the repeatability of the results, each experiment was repeated three times and the reported the average. The results showed that the optimal removal conditions for indomethacin antibiotics were pH = 4, H2O2 oxidant concentration = 50 ppm, Fe2+catalyst concentration = 50 ppm, time = 75 minutes, and initial antibiotic concentration = 20 ppm, with a removal efficiency of 91.03% . The variables of initial antibiotic concentration, H2O2 concentration, and pH had the greatest impact on the removal efficiency of indomethacin. The results of this study indicate that under optimal conditions, more than 90% of indomethacin antibiotics can be removed from aqueous solutions using the Photo-Fenton process, which is a significant result for removing this pharmaceutical pollutant from aquatic environments.

Modelling and optimization of multiple replacement of supplementary cementitious materials for cement composite by response surface method

Supplementary cementitious materials are beneficial in improving performance and lessening the cement consumption with highly lessening CO2 emission. Many researchers used blast furnace slag, bentonite, and active limestone separately or two of them together to improve the performance of cementing materials, however, it is not well known how all react together in cement composite materials. So, the present study used modeling and optimizing the replacement of blast furnace slag, raw bentonite, and active limestone each by the doses of 0 to 20% to maximize strength and minimize the fresh bulk density of cementing materials by central composite design-response surface method (CCD-RSM). The results found, the employment of blast furnace slag, bentonite, and active limestone in the cement composite materials generally lessens the early strength compared to the control mixture. However, the replacement of blast furnace slag and active limestone by 20% significantly improves the 28-days compressive strength while employing raw bentonite by 20% reduced compressive strength by 6.45% compared to the control mixture. However, blending raw bentonite with active limestone by half improved the compressive strength. Besides these, the substitution of bentonite and active limestone reduces the fresh bulk density and flexural strength than the control mixture. Generally, the study optimized depending on the criteria of maximizing strength and minimizing fresh density and found the mix design replacement of blast furnace slag 1.01%, raw bentonite 5.30%, and active limestone 20% that improves 28 days compressive strength simultaneously reduces fresh bulk density in addition to replacing more than 54 different optimized design mix results.

Unveiling the Broad Substrate Specificity of Deoxynivalenol Oxidation Enzyme DepA and Its Role in Detoxifying Trichothecene Mycotoxins.

DepA, a pyrroloquinoline quinone (PQQ)-dependent enzyme isolated from Devosia mutans 17-2-E-8, exhibits versatility in oxidizing deoxynivalenol (DON) and its derivatives. This study explored DepA's substrate specificity and enzyme kinetics, focusing on DON and 15-acetyl-DON. Besides efficiently oxidizing DON, DepA also transforms 15-acetyl-DON into 15-acetyl-3-keto-DON, as identified via LC-MS/MS and NMR analysis. The kinetic parameters, including the maximum reaction rate, turnover number, and catalytic efficiency, were thoroughly evaluated. DepA-PQQ complex docking was deployed to rationalize the substrate specificity of DepA. This study further delves into the reduced toxicity of the transformation products, as demonstrated via enzyme homology modeling and in silico docking analysis with yeast 80S ribosomes, indicating a potential decrease in toxicity due to lower binding affinity. Utilizing the response surface methodology and central composite rotational design, mathematical models were developed to elucidate the relationship between the enzyme and cofactor concentrations, guiding the future development of detoxification systems for liquid feeds and grain processing. This comprehensive analysis underscores DepA's potential for use in mycotoxin detoxification, offering insights for future applications.

Process optimization of superior biosorption capacity of biogenic oyster shells nanoparticles for Congo red and Bromothymol blue dyes removal from aqueous solution: Response surface methodology, equilibrium isotherm, kinetic, and reusability studies

The essential use of natural materials or microbial biomass for effective dye removal from water, combined with simultaneous antimicrobial activity, is crucial for environmental and biomedical applications. Functionalized oyster shell waste nanoparticles (OY-NPs) were synthesized and utilized for efficient biosorption of Congo red (CR) and bromothymol blue (BB) dyes from solution, exhibiting promising antibacterial properties against gram-negative bacteria, specifically Escherichia coli (E. coli), in wastewater. Employing response surface methodology and central composite design, the impact of key process variables; pH, initial concentration, time, and adsorbent doses were investigated. Characterization through scanning electron microscopy, transmission electron microscopy, Fourier transform irradiation, and x-ray diffraction analyses revealed mesoporous crystalline structures rich in CaCO3, featuring prominent functional groups such as C–O, CO, and O-H. Optimization of batch experiments yielded peak efficiency at pH 3.3, initial concentration of 72.34 mg/L, contact time of 84.44 min, and a dosage of 0.1 for CR and BB, achieving a desirability coefficient of 1.0. Equilibrium studies aligned with the Langmuir isotherm model determined coefficient (R2 > 0.977), while kinetic experiments correlated well with the pseudo-second-order model (R2 > 0.9). OY-NPs demonstrated optimal adsorption capacities of 84.77 and 180.61 mg/g for CR and BB, respectively, with spontaneous and endothermic removal. Reusability studies showcased consistently high adsorption efficiency over 5 cycles, highlighting the eco-friendly and recyclable potential of OY-NPs for wastewater treatment applications. The observed antibacterial activity further supports their suitability for antimicrobial applications.

Optimisation of extraction parameters of Aquilaria malaccensis on in vitro antiurolithiatic activities using Response surface methodology (RSM)

The prevalence of urolithiasis has become a concerning issue in Malaysia. Its treatment normally relies on medical processes which are costly and can trigger reoccurrence. Traditional healers have used Aquilaria malaccensis (agarwood) to treat urolithiasis; however, the extraction parameters that result in optimum effectiveness have not been determined. Hence, this research aims to optimise the extraction parameters of A. malaccensis stem on in vitro antiurolithiatic activities by applying response surface methodology (RSM) and central composite design (CCD). The studied parameters were solvent concentration (X1), extraction temperature (X2) and extraction time (X3). Their effects on antiurolithiatic activities (turbidity assay, Y1; titrimetric assay, Y2) were also investigated. The presence of phenols, alkaloids and terpenoids was assessed both qualitatively and quantitatively. The quadratic model was selected for both antiurolithiatic activities as the R2 values achieved were close to 1 and were significantly affected by each studied parameter (p &lt; 0.05). The optimum extraction condition of A. malaccensis stem extract was 100% ethanol, 30.0°C extraction temperature and 30 min extraction time. The extract demonstrated antiurolithiatic activities measured at 83.58 ± 0.75% (turbidity assay) and 86.57 ± 0.80% (titrimetric assay). The phytoconstituents in A. malaccensis stem extracts showed positive correlations with both antiurolithiatic activities. This research has established the reliability of RSM to optimise extraction conditions of A. malaccensis stem to exhibit high antiurolithiatic activities.

Improvement of Cross-linked Alginate Hydrogel Microparticles Loaded with Galangin-β-Cyclodextrin Complex by Response Surface Methodology

AbstractGalangin is a phenolic compound with antioxidant and anti-tyrosinase activity, which makes it highly useful in cosmetics and medicine. However, the poor solubility of galangin in water limits its usefulness in these areas. This study it is aimed to increase the solubility of galangin in water by encapsulation method. Therefore, in this study, ethanolic and methanolic extracts were obtained from Alpinia officinarum Hance, and the phenolic compound profile and content of the extracts were determined by HPLC-DAD. Galangin was purified and fractionated from Alpinia officinarum Hance extracts by column chromatography. Galangin was encapsulated with β-cyclodextrin, and galangin-β-cyclodextrin loaded alginate hydrogel microparticles were developed. The central composite design-response surface methodology was used to develop galangin-β-cyclodextrin loaded alginate hydrogel microparticles under optimum conditions with maximum galangin release. The encapsulation efficiency and release of galangin in galangin-β-cyclodextrin loaded alginate hydrogel microparticles developed under optimum conditions were characterized by HPLC-DAD, surface morphology by SEM, and structural properties by FTIR.

Comparison of an Ultrasound-Assisted Aqueous Two-Phase System Extraction of Anthocyanins from Pomegranate Pomaces by Utilizing the Artificial Neural Network-Genetic Algorithm and Response Surface Methodology Models.

As a by-product of pomegranate processing, the recycling and reuse of pomegranate pomaces (PPs) were crucial to environmentally sustainable development. Ultrasound-assisted aqueous two-phase extraction (UA-ATPE) was applied to extract the anthocyanins (ACNs) from PPs in this study, and the central composite design response surface methodology (CCD-RSM) and artificial neural network-genetic algorithm (ANN-GA) models were utilized to optimize the extraction parameters and achieve the best yield. The results indicated that the ANN-GA model built for the ACN yield had a greater degree of fit and accuracy than the RSM model. The ideal model process parameters were optimized to have a liquid-solid ratio of 49.0 mL/g, an ethanol concentration of 28 g/100 g, an ultrasonic time of 27 min, and an ultrasonic power of 330 W, with a maximum value of 86.98% for the anticipated ACN yield. The experimental maximum value was 87.82%, which was within the 95% confidence interval. A total of six ACNs from PPs were identified by utilizing UHPLC-ESI-HRMS/MS, with the maximum content of cyanidin-3-O-glucoside being 57.01 ± 1.36 mg/g DW. Therefore, this study has positive significance for exploring the potential value of more by-products and obtaining good ecological and economic benefits in the future.

Oxidation of Allura Red AC Using the NaHCO3-activated H2O2 System Catalyzed with Cobalt Supported on Al-PILC

The oxidation of aqueous solutions containing Allura Red AC (AR–AC) using bicarbonate-activated peroxide (BAP) and cobalt-impregnated pillared clay (Co/Al–PILC) as the catalyst was investigated. Using the CCD-RMS approach (central composite design–response surface methodology), the effects of dye, H2O2, and NaHCO3 concentrations on AR–AC degradation were studied. The decolorization, total nitrogen (TN), and total carbon (TC) removals were the analyzed responses, and the experimental data were fitted to empirical quadratic equations for these responses, obtaining coefficients of determination R2 and adjusted-R2 higher than 0.9528. The multi-objective optimization conditions were [dye] = 21.25 mg/L, [H2O2] = 2.59 mM, [NaHCO3] = 1.25 mM, and a catalyst loading of 2 g/L. Under these conditions, a decolorization greater than 99.43% was obtained, as well as TN and TC removals of 72.82 and 18.74%, respectively, with the added advantage of showing cobalt leaching below 0.01 mg/L. Chromatographic analyses (GC–MS and HPLC) were used to identify some reaction intermediates and by-products. This research showed that wastewater containing azo dyes may be treated using the cobalt-catalyzed BAP system in heterogeneous media.

Optimization and Characterization of Adsorbent from Palm Kernel Shell Waste Using H3PO4 Activator

&lt;p class="E-JOURNALHeading1"&gt;Palm kernel shell is solid waste produced from the processing of crude palm oil (CPO). In this context, phosphoric acid (H&lt;sub&gt;3&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;) serves as an essential activator for producing an adsorbent with maximum micropore under operating conditions at a temperature of &amp;lt;450&lt;sup&gt;o&lt;/sup&gt;C. Therefore, this study aimed to determine the optimal adsorbent condition of the palm kernel shell using H&lt;sub&gt;3&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;activator. The production process was optimized using Response Surface Methodology (RSM) and Central Composite Design (CCD) methods with activator concentration variations of 4%, 5%, and 6%, at activation times of 23 hours, 24 hours, and 25 hours, respectively. The quality of the adsorbent produced fulfilled SNI standard 06-3730-1995, characterized by water content of 1.001%, ash content of 5.767%, missing substance level of 18.932%, and fixed carbon content of 75.301%. Furthermore, this work effectively optimized the RSM and CCD adsorbent production process, achieving 4.785% variation in activator concentration and 24.679 hours activation time.&lt;/p&gt;

Optimization for Removal of COD and BOD through RSM-CCD by Activated Sludge Treatment Process for Pharmaceutical Wastewater

Wastewater generated from home and commercial operations is a polluting component of water. One of the main contributors for the production of wastewater by various manufacturing processes is the pharmaceutical industry. The commercial operations of industry are causing an increase in the amount of organic and inorganic contaminants, such as total suspended solids, chemical oxygen demand (COD) and biological oxygen demand (BOD). Activated sludge process reduces COD, BOD and Total Suspended Solids (TSS), with three input variables: pH, time and Mixed Liquor Suspended Solids (MLSS). The Central Composite Design-Response Surface Methodology (CCD-RSM) is used to optimize responses for COD and BOD removal efficiency. To achieve optimization results, numerous sets of trials were conducted for the input variables - pH (4.2–6.5), time (12–30 h) and MLSS (2520–4310 mg/l). The analyzed models were shown to be quadratic and highly significant by the F-value and P-value. The regression coefficients (R2) for the quadratic models developed for removal efficiency, COD, and BOD5 are 0.9996, 0.9995 and 0.9996, respectively. According to CCD-RSM, the optimal matching input factors for the greatest removal efficiency of BOD and COD were: MLLS = 3415 mg/l, time = 21 h and pH = 5.35. Using the traditional method, the maximum removal (95%) of BOD and COD was seen at pH = 6.5, time = 12 h and MLLS = 4310 mg/l.

Performance optimization design of trapped vortex combustion chamber with a sand dune blunt body

In an effort to enhance the performance of the trapped vortex combustion chamber, this paper improved the trapped vortex combustion chamber and proposed a sand dune trapped vortex combustion chamber. Firstly, the effects of different inlet velocities and equivalence ratios on the performance of the two combustion chambers were analyzed. The results showed that under the same operating conditions, the performance of the sand dune trapped vortex combustion chamber was better than that of the trapped vortex combustion chamber. Then, a central composite design (CCD) response surface experimental method was adopted to optimize the structure of the sand dune trapped vortex combustion chamber in detail. The windward angle (α), leeward angle (θ), and rear blunt body height (h) were used as influencing factors. The combustion efficiency (η), pressure loss (δ*), and NOx emissions were used as response variables. Quadratic polynomial regression equations for η, δ*, and NOx emissions were established respectively. Subsequent to this, the expected value function method was employed for multi-objective optimization of the three regression equations. After optimization, compared with the original trapped vortex combustion chamber, the combustion efficiency of the sand dune trapped vortex combustion chamber increased from 87.56 % to 95.41 %, NOx emissions decreased from 747.94 ppm to 386.35 ppm, the outlet temperature distribution factor (OTDF) decreased from 0.21 to 0.07, and field synergy β diminished from 83.11 to 76.60. Although the pressure loss increased from 2.30 % to 3.50 %, this is within an acceptable range.

Enhancing strategies for the activity and H2O resistance of MnCo-CMS flexible SCR catalysts and hydrophobic modification by modulating the surface energy

Melamine sponge is a flexible organic rubber-plastic foam characterized by its highly porous three-dimensional mesh structure. By optimizing the carbonization process of the melamine sponge, NH3-SCR catalysts with enhanced flexibility were developed. In this study, MnCo-CMS (Carbonized melamine sponge) catalysts were synthesized using the impregnation method. Response surface methodology (RSM) and central composite design (CCD) were employed to investigate the effects of impregnation time, loading, and calcination temperature on the mass reaction rate and N2 selectivity. The results showed that loading had the most significant influence, followed by calcination temperature and impregnation time. Under the optimal preparation conditions of 32.5 wt% loading, the calcination temperature at 420 °C, and the impregnation time for 342 min, the mass reaction rate could reach 11.02 cm3min-1g−1, and the N2 selectivity could achieve 87.4 %. Experimental validation confirmed that various preparation processes resulted in catalysts with high SCR activity (rate constant k > 9.5 cm3min-1g−1 and N2 selectivity > 80 %). The Mn-Co loading should be within the range of 28–36 wt%, the calcination temperature within the range of 380–420 °C, and the impregnation time should be 150 min or more. Materials with low surface energy could result in excellent hydrophobicity. In this study, it was found that melamine sponges could be modified into low surface energy carbon foams by temperature modulation. The change in surface energy was utilized as a modification approach to enhance the water resistance of the NH3-SCR catalyst. Importantly, the optimized process significantly improved the stability and water resistance of the catalysts.

Synthesis and optimization of nanoparticles from Phragmites karka improves tomato growth and salinity resilience

Halophytes contain many secondary metabolites that can facilitate the capping and stabilizing of nanoparticles. Synthesis and optimization of zinc oxide nanoparticles from Phragmites karka were performed for the first time in this study to assess the salinity resilience of tomato seedlings in 100 mM NaCl using biotechnological applications and growth analysis. Response surface methodology and central composite design data revealed that ZnO NPs were stable at a 2:1 ratio of plant and salt concentration (pH of 6.5 at 37.5 °C). The peak obtained at 331 nm from UV–Vis spectroscopy confirmed the synthesis of ZnO NPs and these NPs have multiple functional groups. The chemical bond formation of the prepared ZnO NPs (assessed using FTIR and XRD) confirmed the crystalline structure of ZnO NPs that were derived from halophyte P. karka. The SEM images revealed that ZnO NPs have a particle size of 23.5 nm and are spherical, while DLS revealed the size (32.6 nm) and zeta-potential (−6.43 mV) of nanoparticles. Plants treated with ZnO NPs increase the overall tomato growth parameters under salt stress, including shoot length (3-fold), especially at T20 (50 mgL−1 ZnO NPs + 100 mM NaCl) treatment among all growth weeks. The number of leaves increased at T16 (20 mgL−1 ZnO NPs + 100 mM NaCl). The numbers of nodes and internodes were increased at T20 (50 mgL−1 ZnO NPs + 100 mM NaCl) in both parameters. Halophytic nanoparticles could be beneficial sources of biostimulants to improve salt resilience of tomato plants undergoing salt stress.