Optimization of Photo-Fenton Catalyst Preparation Based Bamboo Carbon Fiber by Response Surface Methodology

In this paper,the residue from bamboo factory has been used to design photo-Fenton catalyst,which has the advantages of low cost and magnetic recycling.The photo-Fenton catalytic performance of the biocarbon-based catalyst was excellent and its optimal preparation process was also explored by response surface methodology.First,bamboo-carbon fiber was selected as the photo-Fenton catalyst carrier.Subsequently,the surface of the car-bon fiber was modified,with which dopamine,nano-Fe_(3)O_(4) and nano-TiO_(2) were successively loaded by hydro-thermal method.After the single factor tests,four factors including dopamine concentration,ferric chloride mass,P25 titanium dioxide mass and liquid-solid ratio were selected as the characteristic values.The degradation efficiency of photo-Fenton catalyst to methylene blue(MB)solution was treated as the response value.After the analysis of the response surface optimization,it was shown that the significance sequence of the selected 4 factors in terms of the MB degradation efficiency was arranged as follows:dopamine concentration>liquid-solid ratio>P25 titanium dioxide quality>ferric chloride quality.The optimal process parameters of fiber-carbon catalyst were affirmed as follows:the 1.7 mg/mL concentration of dopamine,the 1.2 g mass of ferric chloride,the 0.2 g mass of P25 titanium dioxide and the liquid-solid ratio of 170 mL/g.The experiment-measured average MB degra-dation efficiency performed by the optimized catalyst was 99.3%,which was nearly similar to the model-predicted value of 98.9%.It showed that the prediction model and response surface model were accurate and reliable.The results from response surface optimization could provide a good reference to design bamboo-based Fenton-like catalyst with excellent catalytic performance.

Response Surface Optimization of Ultrasound-assisted Aqueous Two-phase Extraction of Sweet Potato Leaf Polysaccharides

[Objectives]The ultrasound-assisted aqueous two-phase extraction of sweet potato leaf polysaccharides was studied.[Methods]With the yield of sweet potato leaf polysaccharides as the index,the aqueous two-phase extraction system was determined,and the optimal extraction conditions were optimized by single-factor experiments and response surface methodology.[Results]The optimal parameters were ethanol concentration 25.68%,liquid-to-material ratio 55.83,and ultrasonic treatment time 38.33 min.Under these conditions,the yield of sweet potato leaf polysaccharides could reach 20.646 mg/g.[Conclusions]The ethanol/ammonium sulfate aqueous system is a rapid and efficient method for extracting sweet potato leaf polysaccharides,which is of great significance for the application of sweet potato leaf extract as a natural food additive.

Optimization of Formula of Matsutake Highland Barley Biscuit by Response Surface Methodology

Taking refined flour,matsutake powder,and highland barley powder as main raw materials,this experiment studied the optimal formula of matsutake highland barley biscuit. Besides,single factor experiment was carried out for the amount of highland barley powder,white granulated sugar,and shortening. Then,the response surface optimization analysis was made on crispness and sensory score of the biscuit. The experiment indicates that taking the refined flour as the base 100 g( 100%),the formula of 20% highland barley powder,25% white granulated sugar,and 26% shortening can bake crisp biscuit with complete shape,pure flavor and high quality.

Optimization of the Ultrasonic-assisted Extraction Process for Protocatechuic Acid from Emilia sonchifolia DC by Response Surface Methodology

[Objectives] This study was conducted to optimize the extraction process of protocatechuic acid from Emilia sonchifolia DC. [Methods] The optimal extraction conditions were determined by single factor,response surface analysis and variance analysis,and the content of protocatechuic acid was determined by HPLC. [Results] The protocatechuic acid standard curve equation was: y = 1 435 x + 8 403,R^2= 0. 999 8,indicating a good linear relationship. The optimal extraction conditions were as follows: a temperature at 80 ℃,an extraction time of 1 h,a material-to-liquid ratio at 1:10 and an ultrasonic power of 600 W,and the content of protocatechuic acid extracted was 1. 93 mg/g. The method showed a RSD of 0. 41%,less than 2%,and the detection limit was 0. 0000047261 g/ml.The experimental sample X1 was the low-level 0. 1 mg/ml standard solution,which showed recovery of protocatechuic acid between 100.8% and 105.2%,with a RSD of 0. 013%;and the sample X2 was the high-level 1. 0 mg/ml standard solution,which exhibited recovery between 100. 6% and 102. 2%,with a RSD of 0.076%. Thus,the recovery was high,and the requirements of the performance index were met. [Conclusions] The detection method is stable and reliable and can produce satisfactory results.

Optimization of Inactivation Conditions of High Hydrostatic Pressure Using Response Surface Methodology

Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the optimum response values was verifiedeffectively by the validation data. Effects of temperature, pressure, and pressureholding time on HHP inactivation of Escherichia coli ATCC 8739 were explored. Byanalyzing the response surface plots and their corresponding contour plots as well assolving the quadratic equation, the optimum process parameters for inactivation E. coliof six log cycles were obtained as: temperature 32.2℃, pressure 346.4 MPa, and pressureholding time 12.6min.

Springback Prediction and Optimization of Variable Stretch Force Trajectory in Three-dimensional Stretch Bending Process

Most of the existing studies use constant force to reduce springback while researching stretch force. However, variable stretch force can reduce springback more efficiently. The current research on springback prediction in stretch bending forming mainly focuses on artificial neural networks combined with the finite element simulation. There is a lack of springback prediction by support vector regression（SVR）. In this paper, SVR is applied to predict springback in the three-dimensional stretch bending forming process, and variable stretch force trajectory is optimized. Six parameters of variable stretch force trajectory are chosen as the input parameters of the SVR model. Sixty experiments generated by design of experiments（DOE） are carried out to train and test the SVR model. The experimental results confirm that the accuracy of the SVR model is higher than that of artificial neural networks. Based on this model, an optimization algorithm of variable stretch force trajectory using particle swarm optimization（PSO） is proposed. The springback amount is used as the objective function. Changes of local thickness are applied as the criterion of forming constraints. The objection and constraints are formulated by response surface models. The precision of response surface models is examined. Six different stretch force trajectories are employed to certify springback reduction in the optimum stretch force trajectory, which can efficiently reduce springback. This research proposes a new method of springback prediction using SVR and optimizes variable stretch force trajectory to reduce springback.

Combined Size and Shape Optimization of Structures with DOE,RSM and GA

In this paper,size and shape optimization problem of a machine gun system is addressed with an efficient hybrid method,in which a novel and flexible mesh morphing technique is employed to achieve fast parameterization and modification of complexity structure without going back to CAD for reconstruction of geometric models or to finite element analysis（ FEA） for remodeling. Design of experiments（ DOE） and response surface method（ RSM） are applied to approximate the constitutive parameters of a machine gun system based on experimental tests. Further FEA,secondary development technique and genetic algorithm（ GA） are introduced to find all the optimal solutions in one go and the optimal design of the demonstrated machine gun system is obtained. Results of the rigid-flexible coupling dynamic analysis and exterior ballistics calculation validate the proposed methodology,which is relatively time-saving,reliable and has the potential to solve similar problems.

Saponins Content in Fibrous Roots of Pseudostellaria heterophylla and Optimization of the SEP Extraction Technology

[Objectives]To explore the saponins resources in fibrous roots of Pseudostellaria heterophylla and optimize the SEP technology for extracting saponins.[Methods]Saponins contents in fibrous roots and root tubers of P.heterophylla were compared;with the fibrous roots as host materials,this experiment applied Box-Behnken design to analyze the influence of steam pressure,maintenance pressure time,moisture content of host materials on the content of saponins extracts.[Results]Saponins content was higher in fibrous roots than in tuberous roots of P.heterophylla;the response surface optimization showed that SEP(steam explosion pretreatment)promoted the contents of saponins and extracts in fibrous roots,and the optimal extracting conditions were stream pressure 1.50 Mpa,maintenance pressure time 54 s,and moisture content of host materials 30%.Under this extracting conditions,the verification value of saponins content experiment was 0.441%,36.53%higher than the untreated control group.[Conclusions]This research offered a new method of exploring saponins resources from fibrous roots of P.heterophylla,and provided a reference for developing new medicinal parts of P.heterophylla.

Mathematical Modeling and Optimization of the Microwave Assisted Extraction of the Natural Polyphenols and Flavonoids from the Raw Solid Waste of the Orange Juice Industry

Orange pomace is the solid waste of the orange juice industry which accounts for approximately 50%of the quantity of the fruits processed into juice and is a good raw material for production of high added value products with diverse uses.Orange pomace is rich in polyphenols and flavonoids which can substitute the potentially hazardous or less desirable chemical antioxidants/antimicrobials used in agro-food and cosmetics industry.In this work,an eco-friendly aqueous microwave assisted extraction of orange pomace was investigated and optimized in order to produce aqueous bioactive antioxidant/antimicrobial extracts.A three factorial Response Surface Optimization methodology with centered Box&Behnken experimental design was used to obtain optimum values of total polyphenols and total flavonoids and build predictive models for their optimal extraction conditions.The three optimization factors in terms of applied process parameters were(a)water/solid ratio,(b)extraction temperature and(c)extraction time.The effectiveness and statistical soundness of the two corresponding models regarding optimal total polyphenols and flavonoids were verified by Analysis of Variance(ANOVA).

Mathematical Modeling and Optimization of the Microwave Assisted Extraction of the Solid Waste of the Pomegranate Juice Industry

Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approximately 50%of the quantity of the fruits,which is processed into juice and is a good raw material for production of high added value products with diverse uses.Pomegranate pomace is rich in polyphenols and flavonoids which could substitute the potentially hazardous synthetic antioxidants/antimicrobials used in agro-food and cosmetics sectors.In this work,eco-friendly aqueous microwave assisted extraction of pomegranate pomace was investigated and optimized in order to produce effectively novel natural antioxidant/antimicrobial extracts.A three-factorial response surface optimization methodology with centered Box&Behnken experimental design was used to obtain the predictive models and the maximum values of total polyphenols,total flavonoids and total antioxidant capacity(TAC).The three optimization factors involved were:(a)water/solid ratio;(b)extraction temperature;(c)extraction time and the effectiveness and robustness of the three models were statistically verified by ANOVA.

Experimental Design Technique on Removal of Hydrogen Sulfide using CaO-eggshells Dispersed onto Palm Kernel Shell Activated Carbon：Experiment,Optimization,Equilibrium and Kinetic Studies

This study presents the use of chicken eggshells waste utilizing palm kernel shell based activated carbon（PKSAC） through the modification of their surface to enhance the adsorption capacity of H2S. Response surface methodology technique was used to optimize the process conditions and they were found to be： 500 mg/L for H2S initial concentration, 540 min for contact time and 1 g for adsorbent mass. The impacts of three arrangement factors（calcination temperature of impregnated activated carbon（IAC）, the calcium solution concentration and contact time of calcination） on the H2S removal efficiency and impregnated AC yield were investigated. Both responses IAC yield（IACY, %） and removal efficiency（RE, %） were maximized to optimize the IAC preparation conditions. The optimum preparation conditions for IACY and RE were found as follows： calcination temperature of IAC of 880 ℃, calcium solution concentration of 49.3% and calcination contact time of 57.6 min, which resulted in 35.8% of IACY and 98.2% RE. In addition, the equilibrium and kinetics of the process were investigated. The adsorbent was characterized using TGA, XRD, FTIR, SEM/EDX, and BET. The maximum monolayer adsorption capacity was found to be 543.47 mg/g. The results recommended that the composite of PKSAC and Ca O could be a useful material for H2S containing wastewater treatment.

Pseudomonas sp.ZXY-1,a newly isolated and highly efficient atrazine-degrading bacterium,and optimization of biodegradation using response surface methodology

Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly to keep a safe environment. In the present study, a new atrazine-degrading strain ZXY-1, identified as Pseudomonas, was isolated. This new isolated strain has a strong ability to biodegrade atrazine with a high efficiency of 9.09 mg/L/hr.Temperature, p H, inoculum size and initial atrazine concentration were examined to further optimize the degradation of atrazine, and the synthetic effect of these factors were investigated by the response surface methodology. With a high quadratic polynomial mathematical model（R^2= 0.9821） being obtained, the highest biodegradation efficiency of 19.03 mg/L/hr was reached compared to previous reports under the optimal conditions（30.71°C, pH 7.14, 4.23%（V/V） inoculum size and 157.1 mg/L initial atrazine concentration）.Overall, this study provided an efficient bacterium and approach that could be potentially useful for the bioremediation of wastewater containing atrazine.

Investigation of colloidal biogenic sulfur flocculation:Optimization using response surface analysis

The colloidal properties of biogenic elemental sulfur（S^0）cause solid–liquid separation problems,such as poor settling and membrane fouling.In this study,the separation of S^0 from bulk liquids was performed using flocculation.Polyaluminum chloride（PAC）,polyacrylamide（PAM）and microbial flocculant（MBF）were compared to investigate their abilities to flocculate S^0 produced during the treatment of sulfate-containing wastewater.A novel approach with response surface methodology（RSM）was employed to evaluate the effects and interactions of flocculant dose,pH and stirring intensity,on the treatment efficiency in terms of the S^0 flocculation and the supernatant turbidity removal.The dose optimization results indicated that the S^0 flocculation efficiency decreased in the following order PAC〉MBF〉PAM.Optimum S^0 flocculation conditions were observed at pH 4.73,a stirring speed of 129 r/min and a flocculant dose of 2.42 mg PAC/mg S.During optimum flocculation conditions,the S^0f locculation rate reached 97.53%.Confirmation experiments demonstrated that employing PAC for S^0 flocculation is feasible and RSM is an efficient approach for optimizing the process of S^0 flocculation.The results provide basic parameters and conditions for recovering sulfur during the treatment of sulfate-laden wastewaters.

Modeling and multi-response optimization of machining performance while turning hardened steel with self-propelled rotary tool

There are many advanced tooling approaches in metal cutting to enhance the cutting tool performance for machining hard-to-cut materials. The self propelled rotary tool （SPRT） is one of the novel approaches to improve the cutting tool performance by providing cutting edge in the form of a disk, which rotates about its principal axis and provides a rest period for the cutting edge to cool and allow engaging a fresh cutting edge with the work piece. This paper aimed to present the cutting performance of SPRT while turning hardened EN24 steel and optimize the machining conditions. Surface roughness （Ra） and metal removal rate （rMMR） are considered as machining perfor- mance parameters to evaluate, while the horizontal incli- nation angle of the SPRT, depth of cut, feed rate and spindle speed are considered as process variables. Initially, design of experiments （DOEs） is employed to minimize the number of experiments. For each set of chosen process variables, the machining experiments are conducted on computer numerical control （CNC） lathe to measure the machining responses. Then, the response surface method- ology （RSM） is used to establish quantitative relationships for the output responses in terms of the input variables. Analysis of variance （ANOVA） is used to check the adequacy of the model. The influence of input variables on the output responses is also determined. Consequently, these models are formulated as a multi-response optimi- zation problem to minimize the Ra and maximize the rMMR simultaneously. Non-dominated sorting genetic algorithm-II （NSGA-II） is used to derive the set of Pareto-optimal solutions. The optimal results obtained through the pro- posed methodology are also compared with the results of validation experimental runs and good correlation is found between them.

Optimization of microwave-assisted extraction of wedelolactone from Eclipta alba using response surface methodology

An efficient microwave-assisted extraction tech- nique was used to extract wedelolactone from Eclipta alba. To optimize the effects of the microwave-assisted extraction （MAE） processing parameters on the yield ofwedelolactone, a response surface methodology with a central composite rotatable design was employed. Four independent variables were investigated： microwave power, ethanol concentration, extraction time and the solvent-to-solid ratio. The optimum conditions were： microwave power, 208 W; ethanol con- centration, 90%; extraction time, 26.5 min; and solvent-to- solid ratio, 33 mL.g-~. Under the optimal conditions, the extraction yield of wedelolactone was （82.67±0.16）%, which is in close agreement with the value predicted by the statistical model. MAE was also compared to other conventional methods, including ultrasonic assisted extrac- tion, extraction at room temperature and heat reflux extraction. MAE has distinct advantages for the extraction of wedelolactone in terms of both time and efficiency. Therefore, MAE is a reliable method for the extraction of wedelolactone from Eclipta alba.

Stochastic structural optimization using particle swarm optimization, surrogate models and Bayesian statistics

This paper focuses on a method to solve structural optimization problems using particle swarm optimization （PSO）, surrogate models and Bayesian statistics. PSO is a random/stochastic search algorithm designed to find the global optimum. However, PSO needs many evaluations compared to gradient-based optimization. This means PSO increases the analysis costs of structural optimization. One of the methods to reduce computing costs in stochastic optimization is to use approximation techniques. In this work, surrogate models are used, including the response surface method （RSM） and Kriging. When surrogate models are used, there are some errors between exact values and approximated values. These errors decrease the reliability of the optimum values and discard the realistic approximation of using surrogate models. In this paper, Bayesian statistics is used to obtain more reliable results. To verify and confirm the efficiency of the proposed method using surrogate models and Bayesian statistics for stochastic structural optimization, two numerical examples are optimized, and the optimization of a hub sleeve is demonstrated as a practical problem.

Optimization and evaluation of fish oil rnicrocapsules

Fish oil microcapsules were prepared using two natural polysaccharides, alginate and chitosan, as the wall materials. A response surface methodology （RSM） was used to optimize the conditions for fish oil encapsulation efficiency （FOEE）. The FOEE was investigated with respect to three key-variables in the RSM： ratio of inner oil phase to aqueous phase （X1 w/w）; concentration of the aqueous phase （X2, wt%）; and ratio of the aqueous phase to outer oil phase （X3, v/v）. The optimal formulation obtained from the RSM model, i.e., 2.7：1 （X1）, 1.6 wt% （X2）, and 11.5：1 （X3）, gave a FOEE of 28%. The model was validated and the fish oil microcapsules prepared under the optimized conditions were characterized in terms of particle size, polydispersity index （PDI）, zeta potential, surface morphology, and in vitro release. The average droplet size, PDI, and zeta potential were 915 nm, 0.038, and ＋5.2 mV, respectively. The fish oil microcapsules were highly uniform microspheres, and had an accumulative release rate of 77.7% in 270 min in a gastrointestinal model, indicating their potential as an alternative carrier for the controlled release of fish oil. In conclusion, formulating optimal microencapsulation conditions by the RSM can be applied to the microencapsulation of various oil-soluble nutrients for food applications.

Optimization of residence time distribution in RCDG and an assessment of its applicability in continuous manufacturing

Knowledge of residence time is a critical aspect in developing control and material diversion strategies for continuous manufacturing processes in pharmaceutical manufacturing.Dry granulation is a promising continuous granulation technique as it is fast and economical.In this study,a step-change method to determine residence time in roll compaction/dry granulation is introduced.The factors roll speed and rotational speed of the impeller in the powder inlet unit of the compactor were evaluated using a central composite circumscribed statistical design of experiments in order to optimize the residence time.The fill volume in the compactor was varied exemplarily.It was found that high roll speed,low rotational speed of the impeller and low fill volume in the compactor are beneficial to generate fast transition through the compactor.The impact of roll speed increase was estimated.It can be concluded that despite fast residence time in the process,high roll speed and its subsequent high material throughput can generate a large amount of material that has to be discarded if material diversion is required.

Removal of Cd^(2+) from aqueous solution using graphene oxide modified activate carbon derived from peanut shell

Graphene oxide(GO)was prepared by a modified Hummers method using peanut shells and natural graphite,and graphene oxide modified peanut shells activated carbon composites(GO-AC)were synthesized by co-pyrolysis.The optimal preparation conditions of AC were screened by response surface methodology(RSM)to optimize the preparation process.The results showed that the surface of GO-AC had more micropores and larger specific surface area,increased the surface adsorption sites and had more oxygen-containing functional groups.The adsorption process was mainly based on chemisorption,and the adsorption capacity was 3.45 and 1.30 times higher than that of BC(45.16 mg/g)and AC(119.21 mg/g),respectively.After six adsorption-desorption cycle tests,the adsorption amount of Cd^(2+)by GO-AC was still as high as 89.26 mg/g,with a percentage increase of 93.5%and 365%compared to BC(19.18 mg/g)and AC(46.13 mg/g),respectively,with good reusability.The research can provide a useful reference for the high value-added conversion of waste biomass,and GO-AC loading modified with significant adsorption of Cd2+has good potential for application as a novel and low-cost adsorbent.

Optimized production of a novel bioflocculant M-C11 by Klebsiella sp. and its application in sludge dewatering

The optimized production of a novel bioflocculant M-C11 produced by Klebsiella sp. and its application in sludge dewatering were investigated. The optimal medium carbon source,nitrogen source, metal ion, initial pH and culture temperature for the bioflocculant production were glucose, NaNO3, MgSO4, and pH 7.0 and 25°C, respectively. A compositional analysis indicated that the purified M-C11 consisted of 91.2% sugar, 4.6% protein and 3.9% nucleic acids（m/m）. A Fourier transform infrared spectrum confirmed the presence of carboxyl, hydroxyl,methoxyl and amino groups. The microbial flocculant exhibited excellent pH and thermal stability in a kaolin suspension over a pH range of 4.0 to 8.0 and a temperature range of 20 to 60°C.The optimum bioflocculating activity was observed as 92.37% for 2.56 mL M-C11 and 0.37 g/L CaCl2 dosages using response surface methodology. The sludge resistance in filtration（SRF）decreased from 11.6 × 1012 to 4.7 × 1012m/kg, which indicated that the sludge dewaterability was remarkably enhanced by the bioflocculant conditioning. The sludge dewatering performance conditioned by M-C11 was more efficient than that of inorganic flocculating reagents,such as aluminum sulfate and polymeric aluminum chloride. The bioflocculant has advantages over traditional sludge conditioners due to its lower cost, benign biodegradability and negligible secondary pollution. In addition, the bioflocculant was favorably adapted to the specific sludge pH and salinity.