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•Successfully synthesized BAFPcPDIL heterogeneous photocatalysts and characterized.•Photo-catalytic esterification of alcohols with LA successfully carried out.•The catalyst shows ...admirable photocatalytic activity in the presence of 12 W LED light.•The numerical optimization examines the design expert software using RSM method.•Diesel blended with OL achieved admirable physical and emission properties.
NovelBrønsted acid functionalized phthalocyanine on perylene diimide framework knotted with ionic liquid (BAFPcPDIL) was synthesized and confirmed by instrumentation techniques. DRS-spectrum and Hammett value has been determined to confirm band-gap and proton levels of photo-catalyst respectively. The photo-catalytic performance was evaluated by production of octyl levulinate (OL) using levulinic acid (LA) with n-octyl alcohol (OA) under visible light irradiations. Response surface methodology (RSM)with Box–Behnken design (BBD) with 29 experiments was applied to explore consequences of four crucial process variables: catalyst loading (A), molar ratio of reactants (B) andpower of visible light (C), duration in hour (D) on OL yield. From the model, the optimum conditions for the utmost conversion were found as: 10 mg catalyst with (1:1) alcohol to LA molar ratio under 12 W lamp, in 12 h for completing esterification reaction with 95.58% yield of OL. With optimum conditions, various alkyl esters such as methyl levulinate 92.14%, ethyl levulinate 93.12%, n-propyl levulinate 91.45%, iso-propyl levulinate 92.38%, n-butyl levulinate 85.13%, n-pentyl levulinate 86.35%, n-hexyl levulinate 89.57%, tert-butyl levulinate 91.58%, were successfully synthesized with excellent yields. The plausible photocatalytic mechanismof the esterification reaction was also described. The study was extended on blending of OL with diesel sample in 10–30%, found comparable result of density, kinematic viscosity, calorific values, cetane number, flash, fire and pour point of the blended samples with blank diesel sample and appreciable changes in exhaust gases of 25% blended diesel sample. Additionally, BAFPcPDIL displayed good recyclability without loss of photo reactivity after four runs.
Microwave-steam activation (MSA), an innovative pyrolysis approach combining the use of microwave heating and steam activation, was investigated for its potential production of high grade activated ...carbon (AC) from waste palm shell (WPS) for methylene blue removal. MSA was performed via pyrolytic carbonization of WPS to produce biochar as the first step followed by steam activation of the biochar using microwave heating to form AC. Optimum yield and adsorption efficiency of methylene blue were obtained using response surface methodology involving several key process parameters. The resulting AC was characterized for its porous characteristics, surface morphology, proximate analysis and elemental compositions. MSA provided a high activation temperature above 500 °C with short process time of 15 min and rapid heating rate (≤150 °C/min). The results from optimization showed that one gram of AC produced from steam activation under 10 min of microwave heating at 550 °C can remove up to 38.5 mg of methylene blue. The AC showed a high and uniform surface porosity consisting high fixed carbon (73 wt%), micropore and BET surface area of 763.1 and 570.8 m2/g respectively, hence suggesting the great potential of MSA as a promising approach to produce high grade adsorbent for dye removal.
•Microporous activated carbon (AC) is made via microwave steam activation (MSA).•MSA shows short process time, fast heating rate, low temperature to produce AC.•Optimal yield and adsorption efficiency of AC at 550 °C and 10 min of heating.•85 wt% yield with 38.5 mg of dye/g of AC of adsorption efficiency were obtained.•Low production cost of AC (RM 2.90/kg) suggests the economical feasibility of MSA.
•Microencapsulated of lauric acid with a polystyrene shell was prepared.•A renewable and non-toxic phase change materials has been used for the process.•Emulsion polymerization has been applied as a ...microencapsulated technique.•Response surface method was applied to the statistical design.•The microencapsulated PCM had a good potential for energy storage system.
Thermal energy storage (TES) plays an important role in the development of an efficient solar energy system by storing the solar energy when available during the daytime and use it at night when required. The main component of a TES system is encapsulated phase change materials in macro, micro and nano sacles. Microencapsulated lauric acid (LA) as a renewable (obtained from vegetable oils) and non-toxic Phase Change Material (PCM) with a polystyrene shell was prepared using an emulsion polymerization technique. The individual and interactive effects of operating variables including lauric acid to styrene mass ratio, sodium dodecyl sulfate (SDS) to styrene (St) mass ratio, stirring rate and temperature on the microencapsulation ratio (ME.R) were investigated. Response surface method was applied to the statistical design, analysis of experiments and process optimization. Analysis of Variance (ANOVA) showed that the interaction between the stirring rate and temperature had non-significant effects on ME.R (%). The maximum achieved value of ME.R was 92.3% in the process optimization. It was enhanced compared with microencapsulation ratio of lauric acid in previous studies. By using the optimal values, LA/St mass ratio of 0.42, emulsifier (SDS) to styrene mass ratio of 0.01, stirring rate of 1076 rpm and the temperature of 55 °C, ME.R of 91.64% was obtained. Thermal properties, morphology and thermal stability of the optimal microcapsules were studied using DSC thermograms, Scanning Electron Microscopy (SEM) and thermogravimetry analysis (TGA), respectively. The results showed that microencapsulated renewable PCM with a melting point of 43.77 °C and latent heat of 167.26 kJ/kg has a good potential for utilizing renewable solar energy.
The thermoelectric generator (TEG) can directly convert heat to electricity. However, its efficiency is low, so optimizing TE systems to maximize output power is necessary. Many review papers have ...focused on this technology. However, there has not been a comprehensive review of TEG optimization by a statistical approach. This study reviews thermoelectric generator optimization by the Taguchi method, analysis of variance (ANOVA), and the response surface methodology (RSM) to identify the major optimization findings and tendencies for this technology. Three optimization paths are identified: operating conditions, geometrical configuration, and TE materials for thermoelectric generators (TEGs). Although there is no “one-size-fits-all” combination of characteristics that a TEG system should have, some tendencies based on the results of previous studies have been identified. The key parameters that show the most significant effect on the TEG system for each optimization path are the heat source temperature for the operating conditions and the TE leg height for the geometrical configuration. However, there are no distinctly recognized parameters for TE materials. Thus, these results show that optimizing the heat source conditions of a TEG system will yield the best possible results, and optimizing the TE leg height in the TE module would further improve the system. About 70% of the studies optimizing thermoelectric generators utilized the Taguchi method; thus, the Taguchi method remains the most popular statistical tool for TEG analysis. Finally, the perspectives and challenges of optimizing thermoelectric generators using statistical approaches are underlined.
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•This study reviewers thermoelectric generator optimization by the Taguchi method, ANOVA, and RSM.•Three optimization paths via operating conditions, geometry, and materials are identified.•The review shows that hot-side temperature and TE leg length are the most influential parameters.•No tendency for the optimization of the thermoelectric material properties has been identified.•Mixing different optimization methods gives the most complete analysis of a given system.
► AB1 dye biosorption was studied onto three brown macroalgae. ► Response surface methodology was employed to optimize the experimental conditions. ► Biomass dose, dye concentration and solution pH ...were found to be the main controlling parameters. ► The maximum dye removal efficiency was observed at pH 2.0.
Response surface methodology (RSM) based on three-variable-three-level Box–Behnken design was employed to interpret the adsorption characteristics of Acid Black 1 (AB1) dye onto three brown macroalgae viz.,
Nizamuddin zanardini,
Sargassum glaucescens and
Stoechospermum marginatum. The effects of three independent variables, viz. biomass dosage, dye concentration, and initial solution pH were studied for the removal of AB1 dye by the three macroalgae. A second-order polynomial model successfully described the effects of independent variables on the AB1 dye removal. The maximum experimental dye removal efficiency of 99.27, 98.12 and 97.62% for
N. zanardini,
S. glaucescens and
S. marginatum, respectively, was obtained, which was in agreement with the calculated values. The results of the present study suggest that these macroalgae can be used as an efficient biosorbents for dye removal from aqueous solution.
Big Data applications are typically associated with systems involving large numbers of users, massive complex software systems, and large-scale heterogeneous computing and storage architectures. The ...construction of such systems involves many distributed design choices. The end products (e.g., recommendation systems, medical analysis tools, real-time game engines, speech recognizers) thus involve many tunable configuration parameters. These parameters are often specified and hard-coded into the software by various developers or teams. If optimized jointly, these parameters can result in significant improvements. Bayesian optimization is a powerful tool for the joint optimization of design choices that is gaining great popularity in recent years. It promises greater automation so as to increase both product quality and human productivity. This review paper introduces Bayesian optimization, highlights some of its methodological aspects, and showcases a wide range of applications.
•TBPB and TOPB ILs as demulsifiers are used in breaking water in crude oil emulsions.•Four models for the prediction of demulsification efficiencies are created by RSM.•Temperature, pH, water ...content, concentration, and settling time are optimized.•TBPB and TOPB show acceptable results for light and medium oil emulsion separation.•Crude oil emulsions are completely broken by TOPB at the optimal conditions.
In the present study, the performance of two ionic liquids namely Tetrabutylphosphonium bromide (TBPB) and Tetraoctylphosphonium bromide (TOPB) as the demulsifying compounds are investigated in the demulsification operation of water in light and medium crude oil emulsions for the first time. The response surface methodology (RSM) is employed to evaluate the impact of temperature, pH, water content, demulsifier concentration, and settling time on the demulsification efficiencies of studied demulsifiers. In order to design the requisite experiments and optimize the effective factors on the water removal efficiency, the central composite design (CCD) is applied. To determine the optimal conditions of input parameters, four exact models are created by utilizing the responses of 184 experiments to predict the demulsification efficiencies of two demulsifiers for two types of crude oils based on statistical tests of different models using the analysis of variance (ANOVA). High R2 coefficient values imply that the developed models could reproduce the experimental results of the studied demulsifiers appropriately. At the optimal conditions, the water in light and medium crude oil emulsions are completely broken in the samples containing TOPB. Moreover, TBPB agent presents high and acceptable demulsification efficiencies for both types of crude oils at the optimal values of process parameters i.e. 98.078% and 96.025% for light and medium crude oil emulsions, respectively. The superior demulsification performance of TOPB with respect to TBPB can be ascribed to the longer alkyl chain length of TOPB.
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•ZIF-8 MOF-derived CaO/ZnO nanocatalyst used for transesterification of soybean oil.•RSM-CCD enables efficient optimization of reaction parameters.•A high biodiesel yield of 97.4 % ...was obtained under microwave irradiation.•Catalyst reusability is displayed in up to 5 reaction cycles achieving 87.8 % yield.•According to life cycle cost analysis price of 1 kg of biodiesel is merely $1.11.
In this study a novel, high surface area, and recyclable nano-size solid basic catalyst is developed for the first time from ZIF-8 MOF-derived CaO/ZnO for the high-yielding transesterification of soybean oil (SO) to biodiesel with methanol under microwave irradiation. The chemical composition, texture and morphology of the catalyst were comprehensively characterized by FT-IR, SEM-EDS, XRD, TGA, XPS and BET. In addition, 1H NMR analyses were performed to confirm the conversion of soybean oil to biodiesel, whereas, GC–MS spectrum provide information about the chemical composition of the produced biodiesel. Kinetic studies are performed for the optimized catalyst and it follows the pseudo-first-order reaction. Thermodynamic analyses show that the transesterification of soybean oil to biodiesel reaction is endothermic and not spontaneous. By using Response surface methodology (RSM), the optimization of parameters that affect the biodiesel yield is studied. The transformation of 1:20 soybean oil with methanol using CaO/ZnO catalyst (7 wt%) gives 97.4 % biodiesel yield for the transesterification at 90 °C for 50 min. The catalyst shows good reusability after 5 successive cycles demonstrating its industrial-scale applications. According to Life cycle cost analysis (LCCA) the estimated price of 1 kg of biodiesel produced in this work is merely $1.11 showing high commercial applicability.
Response surface methodology (RSM) is used to optimize the process parameters in casting, welding and machinability studies of composite materials. Response surface methodology is commonly used to ...design the experiments and it minimizes the numbers of experiments for specific number of factors and its levels. It has many advantages over Taguchi method of design. Experiments are conducted as per the experimental design and the responses such as output is recorded. Analysis of variance is used to identify the factors which significantly influence the response. Regression equations are developed to predict the response and the process parameters are optimised for obtaining a specific objective function.
•Optimization of process parameters utilizing response surface methodology.•The optimized processing efficiency achieved 1.56 cm/h, with a roughness of 0.76 µm.•Successful machining of 4-inch diamond ...substrates.
Microsecond-pulsed fiber laser was employed for the surface planarization processing of large-scale freestanding polycrystalline diamond. The effects of process parameters, including rotational processing speed, pulse duration, duty cycle, and line spacing, on the processing outcomes were investigated using statistical approach, specifically, response surface methodology (RSM). As for surface roughness (R), the influence of pulse width was more important than duty cycle and line spacing, while rotational processing speed hardly presented significant influence; however, for material removal rate (S), the impact of line spacing is most pronounced. The laser processing of diamond led to a graphitization, while the observed sputtering of small particles at the laser focus identified as the primary cause for high removal rates. The developed high-energy laser planarization system demonstrated capability in processing of large 4-inch diamond wafers, presenting an effective technology for achieving both higher-quality surfaces and elevated removal rates simultaneously in comparison to mechanical grinding methods.
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