Papers by Keyword: Response Surface Methodology

Abstract: ’This study investigates the mechanical performance of concrete reinforced with recycled polyethylene terephthalate (PET) fibers obtained from discarded plastic bottles, aiming to promote sustainable waste reuse in construction materials. Previous studies on PET fiber reinforced concrete have mainly examined the influence of fiber length and content separately, without considering their combined effects on mechanical properties. In this work, the interactions between fiber length, volume fraction, and mechanical behavior were systematically analyzed using a Central Composite Design (CCD) within the framework of Response Surface Methodology (RSM). Concrete incorporating recycled PET fibers was evaluated at three volume fractions (0.3%, 0.8%, and 1.3%) and three lengths (20 mm, 40 mm, and 60 mm), while maintaining a constant water-to-cement ratio. Sixty specimens were tested to assess both fresh and hardened properties. The greatest loss of workability occurred for the mix containing 1.3% fibers with a length of 60 mm, corresponding to about a 25% reduction compared with the control. Response Surface Methodology (RSM) based on a Central Composite Design (CCD) identified 0.3% fiber content and 40 mm length as the optimal combination, representing the mix that simultaneously maximized both compressive (26 MPa) and tensile strengths (3 MPa) according to the predictive model.

Abstract: Azolla pinnata extract and iron chloride were combined under optimized conditions using Response Surface Methodology (RSM) to synthesize Azolla pinnata-iron oxide nanoparticles (AP-IONPs). The study investigated the effects of three key parameters mixing ratio of iron chloride to Azolla pinnata extract (v/v), solution pH, and mixing temperature on the removal efficiency of nickel (Ni²⁺) ions from aqueous solutions. A Central Composite Design (CCD) was employed to develop two-factor interaction (2FI) and quadratic models describing the influence of these variables on nanoparticle synthesis and adsorption performance. Analysis of Variance (ANOVA) was used to determine the most significant factors affecting Ni removal. The optimal synthesis conditions were identified as a mixing ratio of 2.5:1, solution pH of 2.5, and a temperature of 70 °C. Under these conditions, the predicted and experimental Ni removal efficiencies were 98.1% and 97.1%, respectively, with a prediction error of just 1.02%. Keywords: Green synthesis; Response surface methodology; Azolla pinnata; Nanoparticles Heavy metals; Nickel; Adsorption.

Abstract: In this study, silver nanoparticles (S-AgNPs) were synthesised using S. amaranthoides leaf extract through a green synthesis approach, and their synthesis conditions were optimised using Response Surface Methodology (RSM) based on a Box–Behnken Design (BBD). The model was statistically significant (F-value = 12.21, p < 0.0017) and showed strong predictive capability (adjusted R² = 0.8631). Optimal synthesis was achieved with 1 mL of 1 mM AgNO₃, 20 minutes of extract exposure, and a reaction temperature of 70 °C. Characterisation techniques, including UV–Vis, FTIR, XRD, SEM, and TEM, confirmed the formation of spherical, crystalline S-AgNPs capped with phytochemicals from the plant extract. Antibacterial analysis revealed potent activity, with the optimised S-AgNPs showing a maximum zone of inhibition of 25.8 mm against MRSA, outperforming the standard antibiotic ceftriaxone. These results demonstrate the efficacy of RSM in fine-tuning synthesis parameters to produce bioactive S-AgNPs using an eco-friendly and sustainable approach.

Abstract: Concrete is the most widely used construction material, but its environmental impact and reliance on finite resources have driven the need for more sustainable solutions. This research paper presents the optimization of bamboo fiber and wood ash as supplementary materials in concrete to enhance its mechanical performance and sustainability. A powerful statistical technique known as Response Surface Methodology was employed to systematically investigate the effects of varying bamboo fiber and wood ash content on the compressive and flexural strengths of concrete. The optimal combination of 0.36% bamboo fiber and 13.43% wood ash resulted in a flexural strength of 3.227 MPa and a compressive strength of 18.444 MPa, demonstrating the significant potential of these sustainable materials to improve concrete's mechanical properties. The findings of this study provide valuable insights for the construction industry, highlighting the feasibility of utilizing bamboo fiber and wood ash to develop more durable and environmentally friendly concrete mixtures that can contribute to a more sustainable built environment.

Abstract: The geometric dimension error of plastic parts is one of the common defects in plastic injection molding (PIM). The main reason for this defect is the uniformity of the cooling of the molten plastic. The conformal cooling channel is widely used in injection mold processing due to its excellent cooling effect. However, complex injection molding processes can affect the quality of plastic parts. An optimization model for injection molding process parameters was proposed based on Grey Relational Analysis (GRA) and Response Surface Methodology (RSM). Seven important molding parameters were determined, including injection time, holding pressure, mold temperature, injection pressure, holding time, melt temperature, and mold opening time. The X, Y, and Z directions of plastic part warping deformation were selected as quality indicators. An L18 orthogonal design experiment was established based on the signal-to-noise ratio, calculated the grey relational coefficient and relational degree, and conducted the qualitative analysis to screen and evaluate the influencing factors with high relational degree of holding pressure, holding time, and melt temperature. A second-order polynomial regression model was established using RSM, and a quantitative analysis of warping deformation was conducted. The results showed that when the holding pressure was 110 MPa, the melt temperature was 250 °C, the mold opening time was 6 seconds, the X, Y, and Z direction warping deformations of the optimized product were 0.4354 mm, 0.1411 mm, and 0.2951 mm, respectively, which were reduced by 51.60%, 43.67%, and 45.02% compared to before optimization. The research results have verified the accuracy and reliability of the optimization of injection mold process parameters derived from qualitative and quantitative analysis. It is worth noting that this method has significant advantages in qualitatively identifying the primary and secondary relationships between different conditional parameters and quantitatively determining the optimal combination level for each parameter. This method will provide a framework for optimizing the design parameters of injection molding processes and improve the efficiency of identifying the optimal target combination.

Abstract: The thermal swing adsorption process has been demonstrated as a promising technology for the biogas upgrading process, with ease of integration into renewable electricity sources. This study examined the influence of particle radius, regeneration temperature, and purge-to-feed flow rate ratio on the biogas upgrading process. A dynamic simulation model was developed to study the carbon dioxide capture process. Activated carbon pellets derived from coconut shells were used as the adsorbent material. The adsorption and desorption processes were based on single-component methane and carbon dioxide adsorption isotherms fitted to the Langmuir-Freundlich model. The developed simulation model was validated against experimental data. A particle radius, regeneration temperature, and purge-to-feed flow rate ratio range of 1 to 9 mm, 77 to 227 °C, and 0.1 to 0.7, respectively, were adopted for the parametric analysis. Multi-objective numerical optimization was performed using the response surface methodology. The results indicated that the purge-to-feed flow rate ratio had the highest contribution to the methane purity and recovery models of 92.37 % and 99.90 %, respectively. The optimal methane purity and recovery values obtained were 82.12 % and 37.21 %, respectively, achieved at a particle radius of 9 mm, a regenerating temperature of 227 °C and a purge-to-feed flow rate ratio of 0.4152.

Abstract: Iron tailings are the main component of industrial solid waste. The long-term storage and landfill of iron tailings have caused great pressure on the environment. In this paper, Anshan type high-silicon iron tailings and fly ash were used as the main raw materials to prepare geopolymer. The activity of raw materials was determined by XRD, and geopolymer was prepared by high temperature water culture. The effect of iron tailings content, liquid-solid ratio and curing temperature on geopolymer mechanics was studied. The optimal ratio was determined by regression equation analysis with compressive strength as index. The reaction process of geopolymer was studied through microscopic analysis (XRD, SEM, FTIR), and the changes before and after the reaction of geopolymer were compared to prove the reaction degree of geopolymer, and representative specimens were selected to verify the strength changes under different ratios. The durability of the prepared polymers was tested, and the relevant parameters were determined. The gelling material with good freezing resistance and chemical corrosion resistance was successfully prepared, and the industrial waste was transformed into treasure.

Abstract: Pangasius catfish, also known as striped catfish, is a high-fat fish compared to other freshwater fish like snakehead fish and carp. The oil extracted from this fish contains unsaturated and polyunsaturated fatty acids that are beneficial for health. The quality of the oil is affected by the extraction method, especially the preliminary heating temperature for the extraction. Pangasius catfish oil contains omega-3 fatty acids (EPA and DHA) that have the potential to inhibit inflammation, hyperpigmentation, accelerate skin healing for topical applications, and act as a skin permeation enhancer and oil base for nanoemulsion due to its high oleic acid content. In this research, an experimental design was conducted on pangasius catfish oil extraction using the pressing method to optimize predetermined parameters using Response Surface Methodology (RSM). The factors considered for optimization included the quantity of water and extraction temperatures, with water content ranging from 50% to 150% (w/v) and extraction temperatures ranging from 25°C to 55°C. These ranges were intended to yield results and characterization values of oxidation parameters are tested according to the International Fish Oil Standard (IFOS) through tests including Acid Value (AV), Peroxide Value (PV), Anisidine Value (p-AnV), and Total Oxidation (TOTOX). Subsequently, the optimal conditions were confirmed to obtain the best fish oil results, which were achieved at 1.5 times the amount of pre-treatment water and a pre-treatment temperature of 55°C. The pangasius catfish oil obtained from the confirmation of optimal conditions is used as a raw material for producing nanoemulsions. The D-Optimal Mixture Design of Design Expert approach is utilized to formulate the nanoemulsion. The nanoemulsion formula containing 0.5% pangasius catfish oil was determined as the optimal formula according to the range of physical characteristics of the referenced nanoemulsion preparations with a desirability value of 0.974. This study has demonstrated the potential utility of pangasius catfish oil as a prominent base oil in nanoemulsion products.

Abstract: A pressure-induced autoclave foaming assisted by supercritical CO₂ of degradable polylactide (PLA) has been developed. A central composite design (CCD) of response surface methodology (RSM) is used to optimize three distinct process conditions: foaming temperature, pressure, and time. The mathematical model built for examining the effect of process conditions on the foam density and volume expansion ratio was verified and determined to be acceptable with an R-square value derived from the regression model of 0.930 and 0.934, respectively. The experimental and statistical results showed that of the three factors examined, the foaming pressure had the greatest impact on the density and volume expansion ratio of the PLA foams. The foaming temperature and time also had significant interaction impacts on both responses. It was observed that the following conditions are optimal for foaming of PLA, with a maximum VER of 10.107 and a minimum foam density of 0.123 g/cc: foaming temperature of 165.86 °C and foaming pressure of 152.4 bar for 2.38 h of foaming time.

Abstract: Friction Stir Welding (FSW) is an innovative technique that enhances the conventional method of joining metals. Notably ecofriendly due to its energy efficiency, FSW involves minimal energy input, reduces pollution, and saves time and costs. It finds applications in diverse sectors such as automotive, aerospace, and industry. Each material requires specific process parameters, which leads to this study focusing on identifying suitable parameters for AA7075 aluminum with a 6mm thickness. Using a tool featuring a tapered cylindrical thread pin and a flat shoulder, the study aims to investigate the influence of FSW process parameters, rotation speed, and traverse speed on the mechanical strength of butt joint connections. The study's experimental design varies these parameters and evaluates the joints through tensile strength testing, hardness testing, and macrostructural analysis. Utilizing Response Surface Methodology (RSM), the data highlights the impact of rotation and traverse speed on tensile strength. Hardness test results present variations within heat zones, analyzing the effects of the mentioned variables. The findings demonstrate minimal flash and successful surface outcomes but also identify wormholes within the stir zone (SZ). Tensile strength testing reveals a definite correlation between RPM and traverse speed with joint strength. In contrast, hardness testing indicates that these parameters do not significantly affect joint hardness. Macrostructure examination suggests RPM and traverse speed have negligible effects on the heat-affected zone. In conclusion, FSW presents a sustainable and effective welding approach with implications for multiple industries, and this research provides insights into optimizing its parameters for specific aluminum materials.