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Stringent emission regulations and the depletion of conventional fuel sources drive research on green fuels, additives, and the optimization of fuel injection and exhaust gas recirculation. This study analyzes the impact of butanol additives in diesel and cashew shell liquid biodiesel (CSLB) blends under optimal operating conditions. CSLB was produced with an 85.43% yield from waste cashew nut shell liquid under optimal conditions: a methanol/CSL molar ratio (MR) of 20:1, a process temperature (PT) of 70 °C, and a 4 wt% industrial waste-derived heterogeneous catalyst (IC), using the desirability function approach in the RSM-CCD model. The catalyst was characterized using XRD, FTIR, and BET analyses to confirm its catalytic activity. Engine performance improvements were achieved with specific modifications, including 4° CA timing retardation, 15% split injection, and a 20% exhaust gas recirculation rate when using CSLB blends. In common rail direct injection (CRDI) experimental investigations, diesel and CSLB blends were combined with butanol additives (2.5%, 5%, and 10%) and compared to the baseline test. Incorporating 10% butanol, with its higher latent heat, resulted in a lower combustion temperature, reducing NO x emissions by 47.09% in CSLB10. Additionally, the additive’s lower viscosity and higher oxygen content enhanced atomization, reducing CO (33%) and smoke (23.02%) emissions. However, a slight increase in CO 2 (8.92%) and a decrease in HC emissions (27.14%) were observed in CSLB10. Improved combustion characteristics, reflected in higher peak pressure and heat release rate, resulted in a 4.75% increase in brake thermal efficiency and a 13.92% reduction in brake-specific energy consumption compared to ideal conditions. Overall, this study explores the impact of butanol additives on the performance and emissions of CRDI engines fuelled with CSLB blends derived from waste cashew nut shell liquids, providing insights for sustainable fuel optimization.

The rising demand for alternative fuels stems from fossil fuel depletion, rising crude oil prices, and environmental concerns. Diesel engines, valued for efficiency and durability, contribute to resource depletion and pollution. Biofuels offer a sustainable alternative, with waste lemon peels presenting a viable feedstock for biofuel production. Using a steam distillation process, lemon peel waste oil (LPWO) is extracted from waste lemon peels and test fuel blends of LPWO and conventional diesel have been created in ratios of 5%, 10%, 15%, and 20%. According to the ASTM standards, the properties of LPWO and its blends, along with diesel, have been assessed. The characteristics of LPWO were determined by FTIR, GC-MS, and TG/dTG analysis. The performance, combustion, and emission parameters have been evaluated for neat LPWO and LPWO blends in a variable compression ratio (VCR) engine by varying BP between 0 kW and 5.2 kW and compression ratio from 16:1 to 18:1. From experimental analysis, optimum results are observed while using the blend 5% LPWO, BP 5.2 kW and CR 18:1. LPWO5 showed an increase in BTE and EGT by 2.168% and 3.09% while minimizing BSFC by 6.54%, also improved HRR and in-cylinder pressure; a decrease of CO, NO x , and smoke emissions by 59.42%, 30.99%, and 7.89% whereas 9.14% and 0.201% increase in HC and CO 2 when compared to diesel fuel. To model and optimize the engine responses, a multiple regression model was developed using response surface methodology (RSM) with a desirability function approach (DFA). The optimal operating conditions predicted were 6.51% LPWO blend, 1.42 kW load, and CR 18:1, which closely aligned with experimental findings. The RSM-CCD design coupled with the DFA model yielded a combined desirability value of 0.8997. The VCR engine results were validated with the RSM predictions and DFA optimization, showing an error margin of less than 5%. These outcomes indicate that the LPWO5 blend holds strong potential as a viable alternative fuel for VCR engine applications.

The synthesis of chiral amines is crucial since they are a key component in nearly 40% of top-selling drugs. ω-transaminases are promising biocatalysts for producing these chiral amines. This study reports the isolation of a wild-type Bacillus strain ( Bacillus inaquosorum AGSP2) from a contaminated site at the Amlakhadi river, Gujarat, India. We optimized ω-transaminase production using both One Factor at a Time and Response Surface Methodology- Central Composite Design (RSM-CCD) techniques, with further model validation via an Artificial Intelligence (AI) tool, Support Vector Machine. The optimal medium, called Modified Luria–Bertani, contains fructose (12 g/L), NaCl (7.5 g/L), yeast extract (7.5 g/L), peptone (12 g/L), and α-methylbenzylamine (5 mM). Optimization increased ω-transaminase production 2.8 times, reaching an activity of 6121.88 ± 42 U/ml at 37 °C, pH 7, 120 rpm, with 2% (v/v) inoculum. The RSM-CCD model had R2 = 0.95, predicted R2 = 0.78, RMSE = 0.2327, while SVM achieved R2 = 0.99, predicted R2 = 0.96, RMSE = 0.1327. AGSP2 catalyzed the biotransformation of acetophenone with (S)-α-methylbenzylamine, resulting in a 53.32% conversion rate. These findings demonstrate the potential of combining statistical and AI tools to improve biocatalyst production and applications, presenting a sustainable approach for chiral amine synthesis and highlighting ω-transaminase’s role in green biocatalysis.

This study focuses on optimizing the surface roughness of SiC reinforced Al7039/Cu metal matrix composites (MMCs), crucial for high-precision and durable applications. Using a central composite design (CCD) and response surface methodology (RSM), the research addresses machining challenges posed by MMCs’ abrasive reinforcements and heterogeneous microstructure that typically impair tool performance and surface finish. The authors varied the weight fractions of Al7039, Cu, and SiC in 20 experimental trials, testing compositions of Al7039 (73–91wt. %), Cu (4–12wt. %), and SiC (5–15wt. %). Machining was performed on a Fanuc Series Oi-TF CNC precision lathe, focusing on both rough and finish turning operations to minimize reinforcement particle pullout and optimize surface finish. Surface roughness was quantitatively evaluated using a JB-4C precision roughness meter, and microstructural analysis was conducted on polished and etched specimens under inverted metallurgical microscopy. The study revealed significant effects of compositional variations on surface roughness, with a robust quadratic model (95% confidence) identifying an optimal alloy composition of 91.7% Al7039, 7.2% Cu, and 5% SiC. This composition achieved a predicted average surface roughness of 2.373 µm, closely matching the experimental value of 2.411 µm. These results demonstrate the effectiveness of mechanical and magnetic stirring techniques in promoting homogeneous dispersion of SiC particles and Cu, enhancing both microstructure and machining outcomes. The optimized MMC formulation not only achieves superior surface quality but also opens avenues for further improvements through advanced polishing techniques, making it suitable for demanding industries like aerospace, automotive, and mold tooling.

In this study, we aimed to observe how different operating parameters influenced the photocatalytic degradation of rhodamine B (RhB, cationic dye) and bromophenol Blue (BPB, anionic dye) over ZnO/CuO under visible light irradiation. This further corroborated the optimization study employing the response surface methodology (RSM) based on central composite design (CCD). The synthesis of the ZnO/CuO nanocomposite was carried out using the co-precipitation method. The synthesized samples were characterized via the XRD, FT-IR, FE-SEM, Raman, and BET techniques. The characterization revealed that the nanostructured ZnO/CuO formulation showed the highest surface area (83.13 m2·g−1). Its surface area was much higher than that of pure ZnO and CuO, thereby inheriting the highest photocatalytic activity. To substantiate this photocatalytic action, the investigative analysis was carried out at room temperature, associating first-order kinetics at a rate constant of 0.0464 min−1 for BPB and 0.07091 min−1 for RhB. We examined and assessed the binary interactions of the catalyst dosage, concentration of dye, and irradiation time. The suggested equation, with a high regression R2 value of 0.99701 for BPB and 0.9977 for RhB, accurately matched the experimental results. Through ANOVA we found that the most relevant individual parameter was the irradiation time, followed by catalyst dose and dye concentration. In a validation experiment, RSM based on CCD was found to be suitable for the optimization of the photocatalytic degradation of BPB and RhB over ZnO/CuO photocatalysts, with 98% degradation efficiency.

Austempered ductile iron (ADI) is a hard-to-cut material used for a variety of purposes, including flanges in power plants, oil fields and railway sectors. This article aims to establish a correlation between the surface quality ( R a ), the kerf angle ( K Ta ), and the erosion rate and four critical process variables such as traverse speed ( N S ), abrasive flow rate ( A FR ), water jet pressure ( W JP ), and standoff distance ( S oD ). All of the inferences from the experiments were made using the RSM-CCD response surface methodology and the central composite design. An analysis of variance (ANOVA) was employed to identify which W JP factors had the greatest impact. W JP was shown to be the most influential parameter in the outcomes. The R a and K Ta both fell by 56.7 and 33% when the W JP reached a value of 360 MPa, whereas the MRR increased by 35.46 %. In order to fine-tune the abrasive water jet machining settings of the ADI sample, the desirable analysis is taken to optimize the parameter. Surface morphology and erosion processes of AWJM are studied using a scanning electron microscope and 3D surface roughness analysis.

Foam plugging performance was of great significance for improving oil recovery in reservoir development. In view of the agglomeration phenomenon of SiO2, molecular dynamics simulation was used to verify whether hydrophilic or hydrophobic modification had better dispersion effect on nanoparticles. The effect of SiO2 dispersion was verified by establishing gas–liquid interface model based on molecular dynamics. Meanwhile, SiO2 nanoparticles were modified and the best modification effect was characterized compared with the first modification and the second modification. The dispersion effect of SiO2 nanoparticles was researched by measuring the particle size, observing the morphology by the TEM test and measuring the specific surface area. The foam performance stabilized by SiO2 was evaluated in terms of single factor and multi-factor experimental design through RSM/CCD. According to the result analysis, the modification effect represented hydrophilic was more suitable considering dispersion. Good dispersion of SiO2 nanoparticles was beneficial to slow the decay of foam dispersions and limit the diffusion of water molecules due to interfacial interaction. The effects of second modification were more hydrophilic than the first through FT-IR and TGA. The interfacial tension test showed that the hydrophilic foam dispersion had better foam stability. The optimum foaming condition for single factor was respectively achieved at hydrophilic SiO2 1.5 wt.%, the pH values with 7 and the temperature of 30 °C. The optimum conditions of the foaming volume for multi-factors were 1.506 wt.% hydrophilic SiO2, pH of 8.220 and 31.306 °C, respectively. The best conditions for the half-life were presented to be 1.352 wt.% hydrophilic SiO2, the pH of 7.884 and 26.139 °C, respectively. The maximum foam volume and foam half-life predicted by design 10.0 were 750.241 mL and 358.474 min. Therefore, it was significant to modify the surface of SiO2 nanoparticles (5–25 μm) for improving the dispersion and strengthening the foam stability in high permeability reservoir.

Dark fermentative biohydrogen production (DFBHP) has potential for utilization of rice starch wastewater (RSWW) as substrate. The hydrogen production of Enterobacter aerogenes MTCC 2822 and Clostridium acetobutylicum MTCC 11274, in pure culture and co-culture modes, was evaluated. The experiments were performed in a 2 L bioreactor, for a batch time of 120 h. The co-culture system resulted in highest cumulative hydrogen (1.13 L H2/L media) and highest yield (1.67 mol H2/mol glucose). Two parameters were optimized through response surface methodology (RSM)—substrate concentration (3.0–5.0 g/L) and initial pH (5.5–7.5), in a three-level factorial design. A total of 11 runs were performed in duplicate, which revealed that 4.0 g/L substrate concentration and 6.5 initial pH were optimal in producing hydrogen. The metabolites produced were acetic, butyric, propionic, lactic and isobutyric acids. The volumetric H2 productions, without and with pH adjustments, were 1.24 L H2/L media and 1.45 L H2/L media, respectively.

The present study aims to employ an electrocoagulation reactor containing concentric-aluminum-tubes as electrodes for total organic carbon (TOC) removal from real oily wastewater released from drilling sites located in West Qurna-Iraq. Applied current ranges from 0.5 to 2.0 Amps and contact time ranges from 10 to 40 min had selected as the operational variables. Response surface methodology (RSM) type central composite design (CCD) and MINITAB-statistical soft program had performed to design experiments and analysis of the obtained results. The results showed significant removal of TOC (83.91%) at the optimal values of the operational parameters (1.606 Amps and 40 min). Moreover, the present design of the electrocoagulation reactor was more reliable and cost-effective that could be used in practice efficiently.

Iron-doped hydrochar can effectively remove the methyl orange dye (MO). In this study, iron-doped hydrochar (5% Fe@BC) was successfully synthesized through a two-step hydrothermal carbonization (HTC) process, using FeSO 4 .7H 2 O and sawdust. It was subsequently employed for MO removal. The characterization of the synthesized Fenton-like catalyst (5% Fe@BC) was conducted, using scanning electron microscopy, Fourier-transform infrared and X-ray diffraction techniques to confirm the presence of iron species. The effects of different operating parameters such as catalyst mass, H 2 O 2 concentration, solution pH, organic pollutant concentration, and reaction temperature have been examined. The Box-Behnken design combined with three factors: catalyst mass X 1 , temperature X 2 , organic pollutant concentration X 3 . The response surface methodology coupled with Box-Behnken Design was used to optimize the key variables and response. With this approach, an exhaustive assessment of the variables influencing the optimization process was performed. A significant quadratic model was generated through analysis of variance with a P -value of 0.0001 and an R 2 of 0.99. This confirms a strong relationship between the variables and the response, as well as a high level of model predictability. The optimum conditions were achieved with a catalyst mass of 0.5 g/L, a temperature of 35.5 °C, and an MO concentration of 50 mg/L. The result indicates that 93% of the discoloration efficiency was achieved within 60 min under the optimal conditions. Iron doping in the (5% Fe@BC) plays a crucial role in the degradation and removal of MO. Therefore, the 5% Fe@BC prepared from sawdust and iron salts (FeSO 4 ·7H 2 O) through a two-step HTC process is an inexpensive and effective catalyst for removing organic pollutant from aqueous solutions, using heterogeneous Fenton-like process. Article Highlights Novel iron-doped hydrochar (5%Fe@BC) was synthesized by two-step HTC method. 5%Fe@BC demonstrated excellent performance in degrading and removing MO. Characterized catalyst using SEM, FTIR, and XRD, confirming iron species presence. Explored effects of catalyst mass, H 2 O 2 concentration, pH, MO concentration, and temperature. Employed BBD and RSM for optimization, yielding a significant quadratic model (P = 0.0001, R 2  = 0.99). MO removal efficiency achieved 93% under optimal conditions.