•Comparative study of water-cooled cooler block arrangements led to optimized PVT-III layout using Response Surface Methodology (RSM).•Introduction of 0.3 wt% TiO2/nanofluid, notably enhancing ...electrical efficiency in PVT systems.•Positive correlation identified between rising nanofluid concentration and improved system performance.•Peak electrical efficiencies were attained under elevated solar irradiance and flow rates.
The current study presents a partitioned rectangular-shaped heat sink for improving the PVT system performance. The experiment was examined under various experimental parameters. Five cooler block types with different dimensions were arranged to share the same total contact area with the panel back surface. These cooler blocks were placed in different arrangements, namely (PVT-I, PVT-II, PVT-III, PVT-IV, PVT-V), and studied comparatively using water. The dimensions and numbers of each cooler block arrangement were altered, while maintaining the same surface area in contact with the photovoltaic panel. Through the response surface methodology (RSM) optimization, the optimal arrangement with the best performance was determined, and then TiO2/nanofluid was applied to that arrangement with different volumetric concentrations. Using water, the highest electrical and thermal efficiencies were obtained by case PVT-III with values of 19.39 % and 63.72 %, respectively. This was followed by PVT-II, PVT-V, PVT-I, and PVT-IV in that order for electrical efficiency; and at the same time by PVT-II, PVT-I, PVT-IV, and PVT-V in that order for thermal efficiency. The RSM method recommended the optimal arrangement case as case PVT-III. By using nanofluid in that case arrangement, the highest electrical efficiency value was recorded upon using 0.3 wt% and operating the system at 1.5 L/m and 900 W/m2. Regarding the thermal efficiency results, in that case, the highest and lowest values were recorded upon using 0.3 wt% and 0.1 wt%, respectively, with values of 72.49 % and 31.19 %. Increasing the volumetric concentrations positively reflected on the system's performance, resulting in high efficiencies being achieved. In addition, the highest electrical efficiencies were obtained at high levels of solar irradiance and flow rates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Cellulose, hemicellulose, and lignin constitute the basic components of biomass. Knowledge of the interactions between cellulose and lignin during pyrolysis is crucial for unraveling the pyrolysis ...characteristics of biomass. In this study, for the co-pyrolysis of cellulose and lignin to produce biochar, three influencing factors were selected: pyrolysis temperature (400–800 °C), residence time (5–30 min), and lignin percentage (0–100 %). Pyrolysis experiments were conducted in a vertical tube furnace and the impact of these three factors on the characteristics of biochar was comprehensively explored employing response surface methodology. The results revealed obvious differences between actual values and theoretical values. Specifically, the results showed that the interaction between cellulose and lignin increased the biochar yield, oxygen content, volatile content, and ash content by 6.14 %, 22.85 %, 30.95 %, and 46.75 %, respectively. In contrast, the carbon content, fixed carbon content, and HHV of biochar were relatively reduced by 9.38 %, 11.80 %, and 3.3 %, respectively. Furthermore, Raman spectra of biochar showed that the actual value of graphitization degree of biochar was higher than the theoretical value. This was further corroborated by XPS analysis, wherein owing to the interactions between cellulose and lignin, the actual C-C bond content decreased in contrast to the theoretical value. However, the contents of C-O, CO, COOH functional groups, and aromatic rings increased. Finally, the summary of the co-pyrolysis rules of cellulose and lignin provided a reference for optimal pyrolysis conditions and understanding the mechanism of co-pyrolysis.
•Biochar preparation method from co-pyrolysis of cellulose and lignin is proposed.•Effect of temperature, time, and mass ratio on the biochar property is investigated.•The synergistic effect of cellulose and lignin promotes biochar yield.•Best fitting models for yield and HHV of biochar are quadratic regression equations.•The properties of biochar are further analyzed by FTIR, Raman spectroscopy, and XPS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
There is always uncertainty in industrial manufacturing. These uncertainties have an undesirable impact on the products if deterministic optimization approaches are employed. In order to have ...products as desired, uncertainties must be quantified in the design process. This paper presents a robust design optimization of an outer rotor surface mounted permanent magnet motor with particular application in the hybrid vehicle using the design for six-sigma methodology. Due to very long computational time of robust optimization, a ten high-dimensional surrogate model of the system using the Box-Behnken response surface methodology (RSM) is integrated with the particle swarm optimization (PSO). This causes a significant improvement in the effectiveness and efficiency of optimization. The results acquired from RSM are verified by their simulation using the finite-element method, and the accuracy of RSM is proved. Finally, the deterministic and robust optimized motors are simulated in mass production using Monte Carlo analysis, and six-sigma quality achievements are demonstrated.
The purpose of this research was to achieve the best performance, combustion and emission characteristics of a marine engine fueled with hydrogen (5%, 10% and 15% energy fraction), water (2, 4 and ...6 wt%) and rapeseed methyl ester (RME) blend fuel by the multi-objective optimization. Based on the experimental results of the engine at 50%, 75% and 100% loads, the computational fluid dynamics (CFD) model was developed, and an improved chemical kinetic mechanism was developed to simulate the fuel combustion process. The response surface methodology (RSM) was used to optimize the combustion and emission characteristics of the marine diesel engine. The result showed that the hydrogen and water can improve the combustion and emission characteristics of the marine engine. The best solution was to select the desirable value of 0.632, and the engine achieves the best state by fueling R + 15H + 2.5W at 74.69% load. At the point, the optimum values of brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), nitrogen oxide (NOx), hydrocarbon (HC) and carbon monoxide (CO) emissions were 208.31 g/kW·h, 39.22%, 941.21 ppm, 325.86 ppm and 1073.4 ppm, respectively. For this study, adding appropriate hydrogen and water to biodiesel can achieve efficient, low carbon and clean combustion in marine engine.
•Effects of hydrogen/biodiesel/water blend fuels on combustion and emission characteristics are compared.•Optimum blend fuel is obtained for diesel engine.•An improved 3D model and chemical kinetics mechanism are developed.•The performance optimization was carried out by the response surface methodology.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Phenolics were extracted from MOLs using customised deep eutectic solvents (DES).•DES-based ultrasonic-assisted extraction (UAE) conditions were optimized by RSM.•DES-based UAE exhibited high ...efficiency for the extraction of the phenolic compounds.•DES-based UAE showed strong antioxidant activities.•Phenolic constituents in the MOLs extracts were analyzed.
In this study, an ultrasonic-assisted extraction (UAE) procedure with selected deep eutectic solvents (DES) as solvent was first designed to simultaneously optimize the total phenolic/flavonoid content (TPC/TFC) and antioxidant activities of Moringa oleifera L. leaves (MOLs) by using response surface methodology (RSM). The key factors for RSM were selected based on the design of the experimental results along with a three-factors-five-level, central composite design (CCD), including 20 experimental runs. The analysis of variance (ANOVA) results revealed that the water content in DES had a significant influence on all responses, while the ultrasonic time and the ratio of liquid to solid had no statistically significant effects on the total phenolic content. The optimal conditions of the combination of TPC/TFC and antioxidant activities were obtained as follows: 37% water content in DES, 144 W ultrasonic power, and 40 °C ultrasonic temperature. The measured parameters corresponded with the predicted results. Moreover, a comparative study confirmed that the optimized DES-based UAE yielded further higher TPC, TFC, and antioxidant activities than other extraction methods. The results of HPLC analysis in optimized conditions verified that the MOLs extracts with DES-based UAE included 14 phenolic compounds with high concentrations of vicenin-2 (17.6 mg/g) and orientin (23.6 mg/g). The present study supplied a green and high-efficient method for extracting high levels of anti-oxidative phenolic compounds from MOLs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Good activity of Fe(II)-NClin-CPE for indirect voltammetric determination of dichromate.•Strong effect of pH on the electrode response based on RSM experimental design ...results.•Decrease in oxidation peak current of Fe(II) by adding dichromate to the solution.
A novel, simple, cheap and very sensitive modified carbon paste electrode (CPE) was used for indirect determination of dichromate in aqueous solution. Peak current of Fe(II) redox system exited form Fe(II)-exchanged clinoptilolite nanoparticles modifier (Fe(II)-NClin) at the surface of CPE was decreased in the presence of dichromate. Hence, this decrease in peak current was used for indirect determination of dichromate. Raw and modified zeolite and CPE were characterized by XRD, FT-IR, SEM-EDX, BET, X-ray map, electrochemical impedance spectroscopy (EIS) and TEM techniques. EIS results confirm that the Fe(II)-NClin/CPE has the best charge transfer efficiency with respect to raw CPE and NClin/CPE. To study the effects of more influencing experimental variables (such as modifier% and loaded of Fe(II), solution pH and scan rate) and reducing numbers of experiments experimental design was applied by response surface methodology (RSM). Under optimum conditions, the current response of Fe(II)-NClin/CPE was inversely proportional to Cr2O72− in the concentration range from 2.0×10−9–4.0×10−3molL−1 with a DL of 1.1×10−11molL−1.
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•Potential of biodiesel production from fresh water macroalgae, Rhizoclonium sp. was investigated.•The oil was extracted using hexane solvent extraction method.•Oil extraction ...optimization process done by RSM.•This study signifies that the biodiesel produces from fresh water macroalgae.
Optimization of biodiesel production from freshwater macroalgae, Rhizoclonium sp. was investigated in this study. Biodiesel production process parameters such as chemical solvent extraction, hexane:ether and different extraction techniques were optimized by using the response surface methodology based on the central composite design. Optimization of the transesterification process was conducted by varying two factors each at three different levels and this required a total of thirteen runs. A quadratic model was created to predict the biodiesel yield where the R2 value was found to be 0.97, which indicates the satisfactory accuracy of the model. Based on the results, the optimum process parameters for transesterification of the macroalgae Rhizoclonium sp. oil mixture at an agitation speed of 300 rpm over a period of 180 min was found to be a hexane:ether molar ratio 1:1(40 mL), NaOH catalyst concentration of 1 wt% and reaction temperature of 45 °C. Finally, a process optimization found highest macroalgae oil by simple treatment was 0.376 ± 0.14 g and ultrasonic treatment was 6.044 ± 0.81 g is the highest of biodiesel weight. For transesterification reaction from macroalgae oil, a triglyceride was mixed with 0.25 g methanol converted to biodiesel into methyl esters. The biodiesel weight 0.174 ± 0.034 g and 82.2% of the total fatty acid methyl esters (FAME) were confirmed from gas chromatography (GC) analysis. The biodiesel properties were characterized and the results obtained. Design-Expert Version 11 was used to draw both 3D surface plots and 2D contour plots to predict the optimum biodiesel yield.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The extraction of active ingredients from traditional Chinese medicine has received considerable attentions. In this study, 16 kinds of natural deep eutectic solvent (NADES) with ultrasonic were ...selected to extract saponins from purple yam root and the extraction mechanism was investigated. The results showed that chloride/acrylic acid (1:2; n/n) had the highest extraction yield for saponins. The optimal extraction process parameters were 24% water content, 20 mL/g liquid-solid ratio, and ultrasonic extraction for 85 min (81 °C, 600 W). The extraction rate (ER) of purple yam saponins was 0.935%, close to the fitted result of 96.5 mg/g. Molecular dynamics simulations and FT-IR results showed that the NADES may extract the saponin constituents from purple yam through hydrogen bonding. Compared with traditional extraction methods and molecularly imprinted polymer methods, NADES has a higher ER and lower cost (1.53 $/g), which provides a reference for subsequent industrial quantitative production.
•NADES benefits over traditional solvents: green, efficacy, cost, sustainability.•ChCl/AA-based NADES efficiently extracted saponins with extraction rates >90%.•The extraction mechanism of NADES was demonstrated by DFT and MD simulations.•Hydrogen bonds play vital roles between NADES and target molecules.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Tmax and ∆T in the present hybrid cooling system are significantly lower than both the single liquid cooling and liquid cooling with encapsulant.•Single-factor analysis and sensitivity analysis are ...conducted to identify the effects of influence parameters.•Multi-objective optimization is conducted on structure of hybrid cooling for cylindrical battery module.•The optimized PCM amount is higher than the engineering estimation due to the existence of unmelting portion.•Local optimization of thermal columns can further reduce ∆T and mts of the present hybrid cooling system.
In this work, the advantages of a novel hybrid cooling for a battery module are demonstrated over the single liquid cooling and the encapsulant cases, and then a structural optimization for the hybrid cooling system is conducted based on the response surface methodology (RSM) and numerical modeling. The cooling structure consists of a minichannel cold plate at the bottom, which is also connected to the lateral sides of the batteries in parallel through the thermal columns and heat spreading plate, with high latent heat PCM filled among batteries. Comparing with the single liquid cooling case without PCM, the maximum temperature and temperature difference of the present hybrid cooling system (baseline case) are reduced by about 42.67% and 38.27%, respectively. Single factor analysis is first conducted to identify the significance of different structural parameters based on the sensitivity analysis. Then, the multi-objective optimization is conducted to achieve a balanced design with reduced maximum temperature, temperature difference and thermal system mass by using the central composite design (CCD) combined with RSM. Moreover, a local optimization can further reduce the temperature difference of the battery module. The optimization results show that the final optimized solution (Design 5) can control the temperature difference and thermal system mass of the battery module at the lowest level of 3.7 °C and 107.1 g by maintaining the maximum temperature below 48.5 °C at the high discharge rate of 4C.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
