•The nanoliquid flow over a wedge is modeled using the modified buongiorno model.•The heat transfer rate is optimized using response surface methodology (RSM).•Sensitivity of the heat transfer rate ...towards pertinent parameters is evaluated.•Exponential and thermal-based heat sources are scrutinized in the model.•The thermo-migration and haphazard motion of nanoparticles is examined.
Sensitivity analysis of the heat transfer rate in the flow of the hybrid nanoliquid C2H6O2−H2O (base liquid) +MoS2−Ag (nanoparticles) over a wedge using the Response Surface Methodology (RSM) is carried out. The nanomaterial is modeled using the modified Buongiorno nanofluid model (MBNM) that considers the major slip mechanisms and the effective properties of the hybrid nanoliquid. Two distinct heat sources- linear thermal heat source and an exponential space-dependent heat source are taken into account. The governing nonlinear two-point boundary-layer flow problem is treated numerically. The effects of pertinent parameters on the flow fields in the boundary layer region are represented graphically with suitable physical interpretations. The exponential heat source and slip mechanisms are used to study the sensitivities of the heat transfer rate. Both heat source mechanisms lead to an improvement in the temperature profile, in which the effect of the exponential space-related heat source is predominant. The Brownian motion parameter was found to be the most sensitive to the heat transfer rate.
Lead is used in many industries such as refining, mining, battery manufacturing, smelting. Releases of lead from these industries is one of the major public health concerns due to widespread ...persistence in the environment and its resulting poisoning character. In this work, the castor seed shell (CSS) waste was exploited for preparing a beneficial bio-adsorbent for removal of Pb(II) ions from water. The raw CSS was modified with H3PO4 at different acid concentrations, impregnation ratios, activation times, and temperatures. An optimum adsorption capacity was observed for CSS modified with 2 M acid, 5 mL g−1 solid to liquid ratio, treated at 95 °C for 160 min. Exploiting acid modification, the SEM, XRD, and FTIR analyses show some alterations in functional groups and the surface morphology of the biomass. The impacts of physiochemical variables (initial lead ions concentration, pH, adsorbent dose and adsorption time) on the lead removal percentage were investigated, using response surface methodology (RSM). Maximum removal of 72.26% for raw CSS and 97.62% for modified CSS were obtained at an initial lead concentration (50 mg L−1), pH (5.7), adsorption time (123 min) and adsorbent dosage (1.1 g/100 mL). Isothermal and kinetics models were fitted to adsorption equilibrium data and kinetics data for the modified CSS and the adsorption system was evaluated thermodynamically and from the energy point of view. Isothermal scrutinization indicated the mono-layer nature of adsorption, and the kinetics experimental outcomes best fitted with the pseudo-second-order, implying that the interaction of lead ions and hot acid-treated CSS was the rate-controlling phenomenon of process. Overall, results illustrated that the hot acid-treated biomass-based adsorbent can be considered as an alternative bio-adsorbent for removing lead from water media.
Castor seed shell wastes (A) was treated with hot phosphoric acid to prepare a beneficial bio-adsorbent (B) for Pb (II) removal from waters and a comprehensive study was conducted on the adsorption properties. Display omitted
•Hot phosphoric acid was used for treatment castor seed shell wastes.•The acid-treated biomass was exploited for lead ion removal from waters.•Kinetic and equilibrium studies demonstrated high potential of the adsorbent for this goal.•Thermodynamic consideration revealed spontaneity and feasibility of the process.
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•Membrane cleaning was optimized using response surface methodology.•A model was developed to successfully predict flux recovery after cleaning.•Fouling was characterized by SEM-EDS, ...sodium was the main foulant.•Optimal cleaning is performed for 60 min, with 0.8 wt% Ultrasil 110 at 40 °C.•16% of the cleaning costs can be saved by optimizing membrane cleaning.
Better understanding of membrane fouling and cleaning can help implementation of membrane filtration processes in the pulp and paper industry. The aim of this study was to optimize membrane cleaning in the nanofiltration of kraft black liquor ultrafiltered permeate for the recovery of lignin. This work wants to assess whether the cleaning process removes the main foulants; as well as the economic viability of the optimized cleaning compared to a standard cleaning in a nanofiltration membrane plant on industrial scale.
The optimization of membrane cleaning was investigated using the response surface methodology. The factors studied were time, temperature, and cleaning agent (Ultrasil 110) concentration, and flux recovery was used to evaluate the success of cleaning. Experiments were performed on laboratory scale where flat-sheet polymeric membranes were fouled with kraft black liquor ultrafiltered permeate and cleaned using various combinations of the three factors.
The model developed predicted a flux recovery of 88 % when cleaning was performed for 60 min with a solution of 0.8 wt% Ultrasil 110 at 40 °C. The flux recovery measured experimentally with these cleaning parameters was 80 %. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy analysis confirmed that the optimized cleaning removed the main foulants from the membrane surface. Moreover, increasing the cleaning agent concentration or the cleaning temperature did not always lead to a higher flux recovery. The techno-economic evaluation revealed that 16 % of the cleaning costs could be saved by optimizing the cleaning process.
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•Pervaporation increased esterification conversion by about 16%.•After 5 cycles, the tall oil fatty acids conversion rate is still above 87%.•Under the optimized conditions, the ...esterification conversion was 99.56 ± 0.23 %.•The concentration and rate were simulated by the computational fluid dynamics.
In this study, a solid acid catalyst SO42−/TiO2/ZSM-5 (STZ) was prepared. Biodiesel was synthesized from tall oil fatty acid (TOFA) by the ethanol esterification. The fixed bed and pervaporation (PV) coupling increased the esterification conversion of TOFA and ethanol by about 16 %. The spherical STZ catalyst’s appearance, composition, and catalytic activity were assessed through TGA, XRD, SEM, BET, FTIR, NH3-TPD and XPS analyses. The reaction parameters of ethanol/TOFA molar ratio (10:1–20:1), reaction temperature (75–85 ℃), catalyst dosage (6–12 g) and flow rate (0.3–0.9 mL/min) were optimized by the response surface method (RSM). Under RSM optimization, the TOFA esterification reaction achieved a conversion rate of 99.56 ± 0.23 %. After five cycles of esterification, TOFA conversion remained above 87 %. A computational fluid dynamics (CFD) model was established to predict the esterification reaction behavior in the reactor, and the TOFA conversion rate was found to be close to the experimental results through systematic simulation, by reaction kinetics equation, continuity equation, Navier-Stokes equation, and Brinkman equation. In addition, the TOFA biodiesel prepared by this study complies with EN 14214 and ASTM D6751 standards.
► Successful preparation of ACF-LaFe by SolmeteX for effective phosphate removal. ► Phosphorus adsorption capacity of ACF-LaFe is 29.44mg/g. ► The adsorption mechanisms were investigated by SEM, ...FT-IR and pH analysis. ► Anions had adverse effect on adsorption with the order of F−>SO42->NO3->Cl−.
Rare earth, typical lanthanum, has attracted significant attention due to its high phosphate adsorption capability, but the high price and scarcity of the resources hinder its practical application. In this study, Lanthanum(III) was mixed with Iron(III) to obtain the composite metallic (hydr)oxide which are doped onto activated carbon fiber (ACF), named as ACF-LaFe, for phosphate adsorption. Single-factor and response surface methodology (RSM) were used to optimize the preparation. The phosphate adsorption capacity of ACF-LaFe was calculated to be 29.44mg/g, which is much higher than that of ACF-LaOH or ACF-HFO in our previous reports. Adsorption kinetics and isothermal adsorption studies showed that the pseudo-first-order model and the Langmuir isotherm fitted the experimental data quite well, indicating that the phosphate adsorption onto ACF-LaFe should be monolayer and chemical adsorption with the surface reaction. The phosphate adsorption mechanism was investigated by means of pH study, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR). Ionic competition study showed that the presence of concomitant anions had profounder adverse effect on phosphate adsorption onto ACF-LaFe with the order of F−>SO42->NO3->Cl−. The present study demonstrated that ACF-LaFe would achieve the dual aims of high phosphate removal and low running cost.
This article presents the results of an experimental research on the thermal efficiency (TE) of an evacuated tube solar collector (ETSC) working with a nano-suspension of carbon nanotubes dispersed ...in distillated water. The efficacy of filling ratio (FR) of the heat pipes; the tilt angle (TA) of the collector, and the dispersion mass fraction of the carbon nanotubes within the distillated water on the TE of the collector was investigated. A model was developed based on the response surface methodology (RSM) to optimize the operating conditions in order to maximize the TE of the collector. The accuracy of the RSM model was verified with some additional experiments. It was found that the RSM model is able to optimize the TE of a collector with the accuracy of 1.6%. Also, it was found that the presence of carbon nanotubes inside the evaporator of the heat pipes can promote the nucleate boiling mechanism which in turn increased the TE of the solar collector. Also, the optimum filling ratio value and the installation angle were identified which were 0.6 and 55°, respectively. This was ascribed to a trade-off trend identified between the exist region inside the thermosyphon heat pipe and the amount of the vapor transported between the condenser and evaporator units, and also a trade-off between the residence time of the carrying fluid and the gravity effect, respectively.
•Response surface methodology was used to optimize the performance of a collector.•Statistical Pareto chart was used to find the effective parameters.•Optimum filling ratio and installation angle were calculated.•Relationship and interactions between the parameters were identified.•Nanofluid’s stability was examined using time-settlement experiments.
This study aimed to evaluate the sous-vide cooking and ficin treatment effects on the tenderness of beef steak and optimize it for the elderly using response surface methodology (RSM). The M. ...semitendinosus (ST) from Chikso cattle was shaped into 5 × 5 × 2.54 cm pieces. Ficin solution was injected into the ST steak at 10% of the meat weight, and sous-vide cooked in a water bath at 65 °C for 6 or 12 h. As ficin concentration increased, L*- and a*-value, shear force, and hardness decreased, while soluble peptides increased (P < 0.05). As cooking time increased, cooking loss and collagen solubility of the steak increased (P < 0.05). An interaction effect between ficin and sous-vide cooking was found in L*- and a*-value, shear force, hardness, and soluble peptides (P < 0.05). A model to optimize the hardness for elderly people was established (R2 = 0.7991). Optimization conditions by RSM were 0.86 U/L with 8.87 h (23 N/cm3) for tooth intake (grade 1), 16.31 U/L with 13.24 h (3 N/cm3) for gums intake (grade 2), according to KS H 4897 and Universal Design Foods concept for the elderly. These optimized conditions enable the production of customized products tailored to the oral conditions of elderly people.
This work deals with the optimization of the culture conditions of Bacillus invictae AH1 in order to increase the production level of the proteolytic activity. Response‐surface methodology (RSM) was ...applied for the most significant fermentation parameters (concentration of wheat bran and K2HPO4/KH2PO4) that were earlier identified by Plackett–Burman Design from seven possible factors. A central composite design was used and the quadratic regression model of producing active protease was built. A maximum protease activity was reached and validated experimentally, using a maximum wheat bran concentration (50 g/L) with increased K2HPO4/KH2PO4 concentration (2.275 g/L). Protease production obtained experimentally coincident with the predicted value and the model was proven to be adequate. Interestingly, the use of RSM increased the protease production by four times (7,000 U/mL) using a low‐cost substrate and a culture time of 40 hr, as compared to the standard culture conditions. In the second part of this study, a H2O2‐tolerant alkaline protease produced from B. invictae AH1 with a molecular mass of about 41 kDa, noted P3, was purified by successive steps of ultrafiltration, gel filtration and ion exchange chromatography. The K
m and Vmax values of the purified protease using casein, as substrate, were about 4 mg/mL and 27 μM/min, respectively. The highest enzyme activity was found at pH 9.0 and a temperature of 60°C. In addition, the enzyme showed a quasi‐total stability against H2O2 (5% for 1 hr) and against most of the tested solid and liquid detergents, suggesting its eventual use in bio‐detergent formulations.
In the present analysis 15 experiments were performed in conjunction with the Box-Behnken architecture matrix based on the machining parameter's effect, like spindle speed, feed rate, and cutting ...width., A surface roughness mathematically framework was designed using the surface reaction methods of this model to aid a genetic algorithm. Which is used to decide the optimum machining parameters. Response surface methodology has been used in this paper due to certain advantages as compare to other methodology such as it needs fewer experiments to study the effects of all the factors and the optimum combination of all the variables can be revealed. Finally, a genetic algorithm was used to determine the optimum setting of process parameters that maximize the rate of content removal. The best surface roughness response value obtained from single-objective genetic algorithm optimization was 1.19 μm.
