Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and ...Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and non-linear. In this paper, the effects of charging ratio, inclination angle, and heat input and their interaction effects on heat transfer performance of a looped copper-water OHP are analyzed. First, suppose that the relationship between the response and the variables approximates a second-order model. And use the central composite design to arrange the ex- periment. Then, the method of least squares is used to estimate the parameters in the second-order model. Finally, multi- variate variance analysis is used to analyze the model. The results show that the assumption is right, that is to say, the re- lationship is well modeled by a second-order function. Among the three main effect variables, the effect of inclination angle is the most significant, but their interaction effects are not significant. In the range of the considered factors, both the optimum charging ratio and the optimum inclination angle increase as the heating water flow rate increases.展开更多
This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a l...This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a lab scale thickener for dewatering of tailing in the flotation circuit.Four thickener operating variables,namely feed flowrate,solid percent,flocculant dosage and feedwell height were changed during the tests based on CCRD.The ranges of values of the thickener variables used in the design were a feed flowrate of 9–21 L/min,solid percent of 8%–20%,flocculant dosage of 1.25–4.25 g/t and feedwell height of 16–26 cm.A total of 30 thickening tests were conducted using lab scale thickener on flotation tailing obtained from the Sarcheshmeh copper mine,Iran.The underflow solid percent and bed height were expressed as functions of four operating parameters of thickener.Predicted values were found to be in good agreement with experimental values(R2values of 0.992 and 0.997 for underflow solid percent and bed height,respectively).This study has shown that the RSM and CCRD could effciently be applied for the modeling of thickener for dewatering of flotation tailing.展开更多
[Objectives] The research aimed to optimize extraction process of Clerodendrum philippinum Schauer var. simplex Mlodenke total flavonoids( CPTF),and provide reference for its development and utilization. [Methods] Bas...[Objectives] The research aimed to optimize extraction process of Clerodendrum philippinum Schauer var. simplex Mlodenke total flavonoids( CPTF),and provide reference for its development and utilization. [Methods] Based on single-factor test,ethanol concentration,extraction temperature and extraction time were taken as independent variables,and total flavonoids yield was taken as dependent variable. The test was conducted according to central composite design principle. Multivariate linear regression and binomial equation fitting of the result were conducted,and extraction process of CPTF was optimized by using response surface methodology. [Results]The optimal extraction process of CPTF was as below: ethanol concentration 54. 76%,extraction temperature 83. 92℃,extraction time 102. 64 min,solid-liquid ratio 1:20,extraction for twice. [Conclusions] The extraction process of CPTF by central composite design-response surface methodology was simple and feasible,with reliable prediction result,which was suitable for industrial production.展开更多
The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulf...The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.展开更多
Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simu...Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simultaneously to transform sulphide minerals into useful by-products. To achieve desirable sulphur removal rate and efficiency, central composite design was adopted as a response surface methodology for the optimization and evaluation of the process. A full-quadratic polynomial equation between the sulphur removal and the studied parameters was established to assess the behaviour of sulphur removal as a function of the factors and to predict the results in various conditions. The optimum conditions were obtained based on the variance tests and response surface plots, from which the optimized ranges for each factor resulting in the best response （corresponding to the highest percentage of desulphurization） could be then achieved. The results show that most desirable conditions are atmospheric leaching in 1.39 mol/dm3 nitric acid and 0.88 mol/dm3 sulphuric acid for 47 h. The designed process under the optimized desulphurization conditions was applied to a real iron ore concentrate. More than 75% of the total sulphur was removed via the leaching process. In addition to the desulphurization, the conversion of sulphide-bearing minerals into useful by-products, extraction of valuable metals, and executing the process under atmospheric conditions are the other advantages of the proposed method.展开更多
Central composite design(CCD),together with multiple linear regression,was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography(MEKC) for the determinatio...Central composite design(CCD),together with multiple linear regression,was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography(MEKC) for the determination of albiflorin,paeoniflorin,liquiritin,and glycyrrhizic acid in the traditional Chinese medicine(TCM) prescription,Yangwei granule.Concentrations of sodium deoxycholate(SDC) and borate,and proportions of ammonia,acetonitrile,and methanol were optimized.The total resolutions of peaks between the analytes and their adjacent peaks in real samples were integrated into the evaluation index of separation efficiency.The optimum electrophoretic buffer contained 80 mmol/L SDC,20 mmol/L borate,5%(v/v) methanol,0.5%(v/v) ammonia,and 5%(v/v) acetonitrile.The correlation coefficients(R 2 ) between the peak areas and the corresponding concentrations of analytes were greater than 0.9956.The limits of detection(LODs) (S/N=3) of the analytes were 0.97-4.00μg/ml.The results indicate the superiority of CCD in optimizing the separation conditions of complex samples such as TCM prescriptions.展开更多
The central composite design in the modeling and optimization of catalytic dehydration of ethanol to ethylene was performed to improve the ethylene yield.A total of 20 experiments at random were conducted to investiga...The central composite design in the modeling and optimization of catalytic dehydration of ethanol to ethylene was performed to improve the ethylene yield.A total of 20 experiments at random were conducted to investigate the effect of reaction temperature,Si/Al ratios of H-ZSM-5 catalyst and liquid hourly space velocity(LHSV) on the ethylene yield.The results show that the relationship between ethylene yield and the three significant independent variables can be approximated by a nonlinear polynomial model,with R-squared of 99.9%and adjusted R-squared of 99.8%.The maximal response for ethylene yield is 93.4%under the optimal condition of 328 ℃,Si/Al ratio 85,and LHSV 3.8 h-1.展开更多
Objective:To explore the best extraction technology of safflower polysaccharide by central composite design response surface methodology and evaluate its quality.Methods:Taking the extraction rate of Carthamus tinctor...Objective:To explore the best extraction technology of safflower polysaccharide by central composite design response surface methodology and evaluate its quality.Methods:Taking the extraction rate of Carthamus tinctorius polysaccharide as the index,taking the ratio of solid to liquid,extraction time,extraction temperature and extraction times as the investigation factors,based on the single factor experiment,the central composite design-response surface methodology was used to optimize the optimum extraction process of Carthamus tinctorius polysaccharide and verify it.Results:The response surface model was established with the extraction rate of Carthamus tinctorius polysaccharide as dependent variable Y,the ratio of solid to liquid,extraction time and extraction temperature as independent variables X,P<0.0001.The optimum extraction process was as follows:the ratio of solid to liquid was 1:16.69,the extraction temperature was 91.39℃,and the extraction working time was 89.78min.Under these conditions,the extraction rate of safflower polysaccharide can reach 7.45%,The experimental results show that RSD is 1.05%,and the model can well predict the experimental results.Conclusion:Central Composite Design-Response Surface Methodology has the advantages of high extraction rate,simple,effective and reasonable process operation,high stability and high precision,which can be fully applied to the resource management and utilization of safflower polysaccharide.展开更多
The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibratio...The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity （ETC） of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design （CCD） is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.展开更多
The performances of the response surface methodology(RSM)in connection with the Box–Behnken,face central composite or full factorial design(BBD,FCCD or FFD,respectively)were compared for the use in modeling of the Na...The performances of the response surface methodology(RSM)in connection with the Box–Behnken,face central composite or full factorial design(BBD,FCCD or FFD,respectively)were compared for the use in modeling of the NaOH-catalyzed sunflower oil ethanolysis.The influence of temperature,catalyst loading,and ethanol-to-oil molar ratio(EOMR)on fatty acid ethyl esters(FAEE)content was evaluated.All three multivariate strategies were efficient in the statistical modeling and optimization of the influential process variables but BBD and FCCD realization involved less number of experiments,generating smaller costs,requiring less work and consuming shorter time than the corresponding FFD.All three designs resulted in the same optimal catalyst loading(1.25%of oil)and EOMR(12:1).The reduced two-factorinteraction(2 FI)models based on the BBD and FCCD defined a range of optimal reaction temperature(25℃–75℃)and 25℃,respectively while the same model based on the 33 FFD appointed 75℃.The predicted FAEE content of about 97%–98.0%was close to the experimentally obtained FAEE content of about 97.0%–97.6%under the optimal reaction conditions.Therefore,the simpler BBD or FCCD might successfully be applied for statistical modeling of biodiesel production processes instead of the more extensive,more laborious and more expensive FFD.展开更多
The primary aim of this study is inert COD removal from leachate nanofiltration concentrate because of its high concentration of resistant organic pollutants.Within this framework,this study focuses on the treatabilit...The primary aim of this study is inert COD removal from leachate nanofiltration concentrate because of its high concentration of resistant organic pollutants.Within this framework,this study focuses on the treatability of leachate nanofiltration concentrate through Fenton oxidation and optimization of process parameters to reach the maximum pollutant removal by using response surface methodology(RSM).Initial pH,Fe2+concentration,H_(2)O_(2)/Fe^(2+)molar ratio and oxidation time are selected as the independent variables,whereas total COD,color,inert COD and UV254 removal are selected as the responses.According to the ANOVA results,the R^(2) values of all responses are found to be over 95%.Under the optimum conditions determined by the model(pH:3.99,Fe^(2+):150 mmol/L,H_(2)O_(2)/Fe^(2+):3.27 and oxidation time:84.8 min),the maximum COD removal efficiency is determined as 91.4%by the model.The color,inert COD and UV254 removal efficiencies are determined to be 99.9%,97.2%and 99.5%,respectively,by the model,whereas the total COD,color,inert COD and UV254 removal efficiencies are found respectively to be 90%,96.5%,95.3%and 97.2%,experimentally under the optimum operating conditions.The Fenton process improves the biodegradability of the leachate NF concentrate,increasing the BOD5/COD ratio from the value of 0.04 to the value of 0.4.The operational cost of the process is calculated to be 0.238€/g COD_(removed).The results indicate that the Fenton oxidation process is an efficient and economical technology in improvement of the biological degradability of leachate nanofiltration concentrate and in removal of resistant organic pollutants.展开更多
Food-grade tracers have been developed as an identification technology for grain traceability from original harvest to final destination for transportation.The characteristics of food-grade tracers must be able to sat...Food-grade tracers have been developed as an identification technology for grain traceability from original harvest to final destination for transportation.The characteristics of food-grade tracers must be able to satisfy the environmental demands for grain traceability.To optimize the food-grade tracer production process,the effects of direct compression formulation and load on the mechanical characteristics were studied using response surface methodology(RSM)with central composite design(CCD).Among the four tested formulations,Formulations#2(consisting of 35.00%lactose 100 mesh,64.50%microcrystalline cellulose 102 and 0.50%magnesium stearate)and#4(consisting of 38.00%lactose 100 mesh,50.00%microcrystalline cellulose 102,11.00%pregelatinized starch and 1.00%magnesium stearate)were selected for tracer production based on their physical properties as powders.The value of Carr’s flowability index was 68 for both Formulations#2 and#4,which was the highest among all the formulations.Therefore,Formulations#2 and#4 also had the best powder flowability.The magnesium stearate ratio(1.00%-3.00%)and pressure(6.00-16.00 kgf)were used as independent variables to detect changes in the breaking rate,peak shear force and friction coefficient of tracers compressed by the selected formulations.The optimal production parameters could be achieved at a magnesium stearate ratio of 2.25%and pressure of 16.00 kgf for Formulation#2 and at a magnesium stearate ratio of 1.02%and pressure of 16.00 kgf for Formulation#4.Under these optimal conditions,the tracers had good impact characteristics(breaking rate),compression characteristics(peak shear force)and frictional characteristics(friction coefficient).Moreover,Formulation#2 was more suitable for production because compared to Formulation#4,its breaking rate and friction coefficient values were lower,and its peak shear force value was higher.展开更多
The mathematical models are developed to evaluate the ultimate tensile strength( UTS) and hardness of CNTs / Al2024 composites fabricated by high-energy ball milling. The effects of the preparation variables which are...The mathematical models are developed to evaluate the ultimate tensile strength( UTS) and hardness of CNTs / Al2024 composites fabricated by high-energy ball milling. The effects of the preparation variables which are milling time,rotational speed,mass fraction of CNTs and ball to powder ratio on UST and hardness of CNTs / Al2024 composites are investigated. Based on the central composite design( CCD),a quadratic model is developed to correlate the fabrication variables to the UST and hardness. From the analysis of variance( ANOVA),the most influential factor on each experimental design response is identified. The optimum conditions for preparing CNTs / Al2024 composites are found as follows: 1. 53 h milling time,900 r / min rotational speed,mass fraction of CNTs 2. 87% and Ball to powder ratio 25 ∶ 1. The predicted maximum UST and hardness are 273.30 MPa and 261.36 HV,respectively. And the experimental values are 283.25 MPa and256.8 HV,respectively. It is indicated that the predicted UST and hardness after process optimization are found to agree satisfactory with the experimental values.展开更多
A response surface method was utilized for the finite element model updating of a cable-stayed bridge in this paper to establish a baseline finite element model(FEM)that accurately reflects the characteristics of the ...A response surface method was utilized for the finite element model updating of a cable-stayed bridge in this paper to establish a baseline finite element model(FEM)that accurately reflects the characteristics of the actual bridge structure.Firstly,an initial FEM was established by the large-scale finite element software ANSYS,and the modal analysis was carried out on the dynamic response measured by the actual bridge structural health monitoring system.The initial error was obtained by comparing the dynamic characteristics of the measured data with those of the initial finite element model.Then,the second-order complete polynomial was selected to construct the response surface model;the corrected parameters were chosen using the sensitivity method.The response surface model(RSM)was fitted under the test cases designed using the central composite design method.After constructing the objective function,the RSMwas optimized and iterated by the sequential quadratic programmingmethod to obtain the corrected FEM.Finally,the dynamic characteristics of the modified FEM were compared with those of the actual bridge to get the final error.The results show that the modified FEM simulates the dynamic characteristics of the actual cable-stayed bridges more accurately.展开更多
This study examines the efficacy of Avicennia marina(AM)leaves as an environmentally sustainable biosorbent for the extraction of methylene blue(MB)dye from wastewater.A hybrid approach of Response Surface Methodology...This study examines the efficacy of Avicennia marina(AM)leaves as an environmentally sustainable biosorbent for the extraction of methylene blue(MB)dye from wastewater.A hybrid approach of Response Surface Methodology(RSM)and Artificial Neural Networks(ANN)was implemented to assess,optimize,and forecast biosorption effectiveness across different operating parameters.The experimental design employed a Central Composite Design(CCD)methodology,focusing on critical parameters including pH,initial dye concentration,temperature,and biosorbent dosage.The ideal biosorption parameters were identified as a temperature of 44.3℃,pH 7.1,a biosorbent dosage of 0.3 grams,and an initial dye concentration of 48.4 mg/L,resulting in a maximum removal efficiency of 84.26%.The ANN model exhibited significant prediction accuracy,so confirming its appropriateness for predicting and enhancing intricate biosorption processes.The findings underscore that AM leaves constitute a cost-efficient,plentiful,and ecologically sustainable resource for wastewater treatment purposes.Furthermore,the amalgamation of RSM and ANN shown significant efficacy in process optimization and forecasting.These findings provide significant insights into the advancement of eco-friendly solutions for the treatment of dye-contaminated water.Subsequent study must prioritize the amplification of the procedure for industrial applications,the execution of ongoing system assessments,and the evaluation of the enduring environmental and economic ramifications of utilizing AM leaves as a biosorbent.展开更多
The objectives of this present investigation were to develop and formulate nimesulide bilayer tablets by using different polymer combinations and fillers, to optimize the formulations for different drug release variab...The objectives of this present investigation were to develop and formulate nimesulide bilayer tablets by using different polymer combinations and fillers, to optimize the formulations for different drug release variables by orthogonal design and central composite design-surface methodology and to evaluate drug release pattern of the optimized product. The bilayer tablet containing a fast release layer（FRL） and a sustained release layer（SRL） provided an initial burst release of nimesulide, followed by the sustained release for a period of time. The optimal formulation obtained was as follows：（I） the formulation of FRL： nimesulide, 50 mg; lactose, 92 mg; starch, 22 mg; CCMC-Na, 14 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; magnesium stearate, 0.9 mg; and iron oxide red, 0.1 mg; and（II） the formulation of SRL： nimesulide, 150 mg; HPMC K100LV, 26 mg; HPMC K4M, 33 mg; lactose, 54 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; and magnesium stearate, 0.9 mg. According to the optimal formulation, the biphasic type of release was identified. The in vitro drug dissolution from the bilayer tablets was sustained for about 16 h after releasing 15% of drug in the first 10 min. The developed nimesulide bilayer tablets with improved efficacy can perform therapeutically better than the conventional tablets.展开更多
The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was use...The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was used for the optimization.Independent variables were extraction temperature,extraction pressure and entrainer flow rate.Dependent variable was yield ratio of icariin from Herba Epimedii.A two-order polynomial equation was fitted to the data.The results showed that the optimum extraction conditions were as follows:extraction temperature 46.5℃,extraction pressure 30.6 MPa,entrainer flow rate 3.3 mL/min.CCD/ RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.展开更多
To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based gen...To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental(CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model(RSM) was set up and the results of the analysis of variance(ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the "trial and error" procedure.展开更多
Different multidisciplinary design optimization （MDO） problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the...Different multidisciplinary design optimization （MDO） problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the referred vehicle, three disciplines have been considered, which are trajectory, propulsion and aerodynamics. A special design structure matrix is developed to assist data exchange between disciplines. This design process uses response surface method （RSM） for multidisciplinary optimization of the rocket. The RSM is applied to the design in two categories： the propulsion model and the system level. In the propulsion model, RSM determines an approximate mathematical model of the engine output parameters as a function of design variables. In the system level, RSM fits a surface of objective function versus design variables. In the first MDO problem formulation, two design variables are selected to form propulsion discipline. In the second one, three new design variables from geometry are added and finally, an optimization method is applied to the response surface in the system level in order to find the best result. Application of the first developed multidisciplinary design optimization procedure increased accessible altitude （performance index） of the referred sounding rocket by twenty five percents and the second one twenty nine.展开更多
基金Supported by the Natural Science Foundation of Ministry of Education of Jiangsu Province (02KJB470001).
文摘Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and non-linear. In this paper, the effects of charging ratio, inclination angle, and heat input and their interaction effects on heat transfer performance of a looped copper-water OHP are analyzed. First, suppose that the relationship between the response and the variables approximates a second-order model. And use the central composite design to arrange the ex- periment. Then, the method of least squares is used to estimate the parameters in the second-order model. Finally, multi- variate variance analysis is used to analyze the model. The results show that the assumption is right, that is to say, the re- lationship is well modeled by a second-order function. Among the three main effect variables, the effect of inclination angle is the most significant, but their interaction effects are not significant. In the range of the considered factors, both the optimum charging ratio and the optimum inclination angle increase as the heating water flow rate increases.
基金supported by the National Iranian Copper Industry Co.
文摘This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a lab scale thickener for dewatering of tailing in the flotation circuit.Four thickener operating variables,namely feed flowrate,solid percent,flocculant dosage and feedwell height were changed during the tests based on CCRD.The ranges of values of the thickener variables used in the design were a feed flowrate of 9–21 L/min,solid percent of 8%–20%,flocculant dosage of 1.25–4.25 g/t and feedwell height of 16–26 cm.A total of 30 thickening tests were conducted using lab scale thickener on flotation tailing obtained from the Sarcheshmeh copper mine,Iran.The underflow solid percent and bed height were expressed as functions of four operating parameters of thickener.Predicted values were found to be in good agreement with experimental values(R2values of 0.992 and 0.997 for underflow solid percent and bed height,respectively).This study has shown that the RSM and CCRD could effciently be applied for the modeling of thickener for dewatering of flotation tailing.
基金Supported by Special Item for Guangxi Bagui Scholars(Guicaijiaohan [2017]143)
文摘[Objectives] The research aimed to optimize extraction process of Clerodendrum philippinum Schauer var. simplex Mlodenke total flavonoids( CPTF),and provide reference for its development and utilization. [Methods] Based on single-factor test,ethanol concentration,extraction temperature and extraction time were taken as independent variables,and total flavonoids yield was taken as dependent variable. The test was conducted according to central composite design principle. Multivariate linear regression and binomial equation fitting of the result were conducted,and extraction process of CPTF was optimized by using response surface methodology. [Results]The optimal extraction process of CPTF was as below: ethanol concentration 54. 76%,extraction temperature 83. 92℃,extraction time 102. 64 min,solid-liquid ratio 1:20,extraction for twice. [Conclusions] The extraction process of CPTF by central composite design-response surface methodology was simple and feasible,with reliable prediction result,which was suitable for industrial production.
基金supported by the National Science and Technology Council of Mexico(CONACYT)(No.192118)
文摘The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.
文摘Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simultaneously to transform sulphide minerals into useful by-products. To achieve desirable sulphur removal rate and efficiency, central composite design was adopted as a response surface methodology for the optimization and evaluation of the process. A full-quadratic polynomial equation between the sulphur removal and the studied parameters was established to assess the behaviour of sulphur removal as a function of the factors and to predict the results in various conditions. The optimum conditions were obtained based on the variance tests and response surface plots, from which the optimized ranges for each factor resulting in the best response （corresponding to the highest percentage of desulphurization） could be then achieved. The results show that most desirable conditions are atmospheric leaching in 1.39 mol/dm3 nitric acid and 0.88 mol/dm3 sulphuric acid for 47 h. The designed process under the optimized desulphurization conditions was applied to a real iron ore concentrate. More than 75% of the total sulphur was removed via the leaching process. In addition to the desulphurization, the conversion of sulphide-bearing minerals into useful by-products, extraction of valuable metals, and executing the process under atmospheric conditions are the other advantages of the proposed method.
基金Project supported by the National Science and Technology Major Project of Ministry of Science and Technology of China(No. 2009ZX09313-036)the Program for New Century Excellent Talents in University of Ministry of Education of China(No.NCET-06-0515)
文摘Central composite design(CCD),together with multiple linear regression,was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography(MEKC) for the determination of albiflorin,paeoniflorin,liquiritin,and glycyrrhizic acid in the traditional Chinese medicine(TCM) prescription,Yangwei granule.Concentrations of sodium deoxycholate(SDC) and borate,and proportions of ammonia,acetonitrile,and methanol were optimized.The total resolutions of peaks between the analytes and their adjacent peaks in real samples were integrated into the evaluation index of separation efficiency.The optimum electrophoretic buffer contained 80 mmol/L SDC,20 mmol/L borate,5%(v/v) methanol,0.5%(v/v) ammonia,and 5%(v/v) acetonitrile.The correlation coefficients(R 2 ) between the peak areas and the corresponding concentrations of analytes were greater than 0.9956.The limits of detection(LODs) (S/N=3) of the analytes were 0.97-4.00μg/ml.The results indicate the superiority of CCD in optimizing the separation conditions of complex samples such as TCM prescriptions.
基金Supported by National Natural Science Foundation of China(No.70671072)
文摘The central composite design in the modeling and optimization of catalytic dehydration of ethanol to ethylene was performed to improve the ethylene yield.A total of 20 experiments at random were conducted to investigate the effect of reaction temperature,Si/Al ratios of H-ZSM-5 catalyst and liquid hourly space velocity(LHSV) on the ethylene yield.The results show that the relationship between ethylene yield and the three significant independent variables can be approximated by a nonlinear polynomial model,with R-squared of 99.9%and adjusted R-squared of 99.8%.The maximal response for ethylene yield is 93.4%under the optimal condition of 328 ℃,Si/Al ratio 85,and LHSV 3.8 h-1.
基金National Natural Science Foundation of China(No.81603418)General Program of Natural Science Foundation of Heilongjiang(No.H201472)Project of Excellent Youth Talents of Heilongjiang(No.2020YQ05)。
文摘Objective:To explore the best extraction technology of safflower polysaccharide by central composite design response surface methodology and evaluate its quality.Methods:Taking the extraction rate of Carthamus tinctorius polysaccharide as the index,taking the ratio of solid to liquid,extraction time,extraction temperature and extraction times as the investigation factors,based on the single factor experiment,the central composite design-response surface methodology was used to optimize the optimum extraction process of Carthamus tinctorius polysaccharide and verify it.Results:The response surface model was established with the extraction rate of Carthamus tinctorius polysaccharide as dependent variable Y,the ratio of solid to liquid,extraction time and extraction temperature as independent variables X,P<0.0001.The optimum extraction process was as follows:the ratio of solid to liquid was 1:16.69,the extraction temperature was 91.39℃,and the extraction working time was 89.78min.Under these conditions,the extraction rate of safflower polysaccharide can reach 7.45%,The experimental results show that RSD is 1.05%,and the model can well predict the experimental results.Conclusion:Central Composite Design-Response Surface Methodology has the advantages of high extraction rate,simple,effective and reasonable process operation,high stability and high precision,which can be fully applied to the resource management and utilization of safflower polysaccharide.
基金Supported by National Natural Science Foundation of China(Grant Nos.51105092,61403106)International Science and Technology Cooperation Program of China(Grant No.2014DFR50250)the 111 Project,China(Grant No.B07018)
文摘The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity （ETC） of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design （CCD） is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.
基金Supported jointly by the Ministry of Education,485 Science and Technological Development of the Republic of Serbia(Project 4Q8614 Ⅲ 45001)a part of the Project 0-14-18 of the SASA Branch in Nis 487(Development,modeling and optimization of biodiesel production from 4Q8815 nonedible and waste feedstocks),Serbia
文摘The performances of the response surface methodology(RSM)in connection with the Box–Behnken,face central composite or full factorial design(BBD,FCCD or FFD,respectively)were compared for the use in modeling of the NaOH-catalyzed sunflower oil ethanolysis.The influence of temperature,catalyst loading,and ethanol-to-oil molar ratio(EOMR)on fatty acid ethyl esters(FAEE)content was evaluated.All three multivariate strategies were efficient in the statistical modeling and optimization of the influential process variables but BBD and FCCD realization involved less number of experiments,generating smaller costs,requiring less work and consuming shorter time than the corresponding FFD.All three designs resulted in the same optimal catalyst loading(1.25%of oil)and EOMR(12:1).The reduced two-factorinteraction(2 FI)models based on the BBD and FCCD defined a range of optimal reaction temperature(25℃–75℃)and 25℃,respectively while the same model based on the 33 FFD appointed 75℃.The predicted FAEE content of about 97%–98.0%was close to the experimentally obtained FAEE content of about 97.0%–97.6%under the optimal reaction conditions.Therefore,the simpler BBD or FCCD might successfully be applied for statistical modeling of biodiesel production processes instead of the more extensive,more laborious and more expensive FFD.
文摘The primary aim of this study is inert COD removal from leachate nanofiltration concentrate because of its high concentration of resistant organic pollutants.Within this framework,this study focuses on the treatability of leachate nanofiltration concentrate through Fenton oxidation and optimization of process parameters to reach the maximum pollutant removal by using response surface methodology(RSM).Initial pH,Fe2+concentration,H_(2)O_(2)/Fe^(2+)molar ratio and oxidation time are selected as the independent variables,whereas total COD,color,inert COD and UV254 removal are selected as the responses.According to the ANOVA results,the R^(2) values of all responses are found to be over 95%.Under the optimum conditions determined by the model(pH:3.99,Fe^(2+):150 mmol/L,H_(2)O_(2)/Fe^(2+):3.27 and oxidation time:84.8 min),the maximum COD removal efficiency is determined as 91.4%by the model.The color,inert COD and UV254 removal efficiencies are determined to be 99.9%,97.2%and 99.5%,respectively,by the model,whereas the total COD,color,inert COD and UV254 removal efficiencies are found respectively to be 90%,96.5%,95.3%and 97.2%,experimentally under the optimum operating conditions.The Fenton process improves the biodegradability of the leachate NF concentrate,increasing the BOD5/COD ratio from the value of 0.04 to the value of 0.4.The operational cost of the process is calculated to be 0.238€/g COD_(removed).The results indicate that the Fenton oxidation process is an efficient and economical technology in improvement of the biological degradability of leachate nanofiltration concentrate and in removal of resistant organic pollutants.
基金This work was supported by the National Natural Science Foundation of China(31401610)the Fundamental Research Funds for the Central Universities of China(KJON201557)+1 种基金the Outstanding Youth Foundation Science and Technology Fund of College of Engineering at Nanjing Agricultural University(YQ201603)the Jiangsu Agriculture Science and Technology Innovation Fund(CX(16)1059).
文摘Food-grade tracers have been developed as an identification technology for grain traceability from original harvest to final destination for transportation.The characteristics of food-grade tracers must be able to satisfy the environmental demands for grain traceability.To optimize the food-grade tracer production process,the effects of direct compression formulation and load on the mechanical characteristics were studied using response surface methodology(RSM)with central composite design(CCD).Among the four tested formulations,Formulations#2(consisting of 35.00%lactose 100 mesh,64.50%microcrystalline cellulose 102 and 0.50%magnesium stearate)and#4(consisting of 38.00%lactose 100 mesh,50.00%microcrystalline cellulose 102,11.00%pregelatinized starch and 1.00%magnesium stearate)were selected for tracer production based on their physical properties as powders.The value of Carr’s flowability index was 68 for both Formulations#2 and#4,which was the highest among all the formulations.Therefore,Formulations#2 and#4 also had the best powder flowability.The magnesium stearate ratio(1.00%-3.00%)and pressure(6.00-16.00 kgf)were used as independent variables to detect changes in the breaking rate,peak shear force and friction coefficient of tracers compressed by the selected formulations.The optimal production parameters could be achieved at a magnesium stearate ratio of 2.25%and pressure of 16.00 kgf for Formulation#2 and at a magnesium stearate ratio of 1.02%and pressure of 16.00 kgf for Formulation#4.Under these optimal conditions,the tracers had good impact characteristics(breaking rate),compression characteristics(peak shear force)and frictional characteristics(friction coefficient).Moreover,Formulation#2 was more suitable for production because compared to Formulation#4,its breaking rate and friction coefficient values were lower,and its peak shear force value was higher.
基金Sponsored by the Program for Innovative Research Team in University of Yunnan Province and Major Projects of Yunnan Province(Grant No.2014FC001)
文摘The mathematical models are developed to evaluate the ultimate tensile strength( UTS) and hardness of CNTs / Al2024 composites fabricated by high-energy ball milling. The effects of the preparation variables which are milling time,rotational speed,mass fraction of CNTs and ball to powder ratio on UST and hardness of CNTs / Al2024 composites are investigated. Based on the central composite design( CCD),a quadratic model is developed to correlate the fabrication variables to the UST and hardness. From the analysis of variance( ANOVA),the most influential factor on each experimental design response is identified. The optimum conditions for preparing CNTs / Al2024 composites are found as follows: 1. 53 h milling time,900 r / min rotational speed,mass fraction of CNTs 2. 87% and Ball to powder ratio 25 ∶ 1. The predicted maximum UST and hardness are 273.30 MPa and 261.36 HV,respectively. And the experimental values are 283.25 MPa and256.8 HV,respectively. It is indicated that the predicted UST and hardness after process optimization are found to agree satisfactory with the experimental values.
基金supported by the National Natural Science Foundation of China(NNSFC)(Grant no.12272148).
文摘A response surface method was utilized for the finite element model updating of a cable-stayed bridge in this paper to establish a baseline finite element model(FEM)that accurately reflects the characteristics of the actual bridge structure.Firstly,an initial FEM was established by the large-scale finite element software ANSYS,and the modal analysis was carried out on the dynamic response measured by the actual bridge structural health monitoring system.The initial error was obtained by comparing the dynamic characteristics of the measured data with those of the initial finite element model.Then,the second-order complete polynomial was selected to construct the response surface model;the corrected parameters were chosen using the sensitivity method.The response surface model(RSM)was fitted under the test cases designed using the central composite design method.After constructing the objective function,the RSMwas optimized and iterated by the sequential quadratic programmingmethod to obtain the corrected FEM.Finally,the dynamic characteristics of the modified FEM were compared with those of the actual bridge to get the final error.The results show that the modified FEM simulates the dynamic characteristics of the actual cable-stayed bridges more accurately.
文摘This study examines the efficacy of Avicennia marina(AM)leaves as an environmentally sustainable biosorbent for the extraction of methylene blue(MB)dye from wastewater.A hybrid approach of Response Surface Methodology(RSM)and Artificial Neural Networks(ANN)was implemented to assess,optimize,and forecast biosorption effectiveness across different operating parameters.The experimental design employed a Central Composite Design(CCD)methodology,focusing on critical parameters including pH,initial dye concentration,temperature,and biosorbent dosage.The ideal biosorption parameters were identified as a temperature of 44.3℃,pH 7.1,a biosorbent dosage of 0.3 grams,and an initial dye concentration of 48.4 mg/L,resulting in a maximum removal efficiency of 84.26%.The ANN model exhibited significant prediction accuracy,so confirming its appropriateness for predicting and enhancing intricate biosorption processes.The findings underscore that AM leaves constitute a cost-efficient,plentiful,and ecologically sustainable resource for wastewater treatment purposes.Furthermore,the amalgamation of RSM and ANN shown significant efficacy in process optimization and forecasting.These findings provide significant insights into the advancement of eco-friendly solutions for the treatment of dye-contaminated water.Subsequent study must prioritize the amplification of the procedure for industrial applications,the execution of ongoing system assessments,and the evaluation of the enduring environmental and economic ramifications of utilizing AM leaves as a biosorbent.
基金Important National Science & Technology Specific Projects of China(Grant No.2012ZX09301003-001-009)
文摘The objectives of this present investigation were to develop and formulate nimesulide bilayer tablets by using different polymer combinations and fillers, to optimize the formulations for different drug release variables by orthogonal design and central composite design-surface methodology and to evaluate drug release pattern of the optimized product. The bilayer tablet containing a fast release layer（FRL） and a sustained release layer（SRL） provided an initial burst release of nimesulide, followed by the sustained release for a period of time. The optimal formulation obtained was as follows：（I） the formulation of FRL： nimesulide, 50 mg; lactose, 92 mg; starch, 22 mg; CCMC-Na, 14 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; magnesium stearate, 0.9 mg; and iron oxide red, 0.1 mg; and（II） the formulation of SRL： nimesulide, 150 mg; HPMC K100LV, 26 mg; HPMC K4M, 33 mg; lactose, 54 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; and magnesium stearate, 0.9 mg. According to the optimal formulation, the biphasic type of release was identified. The in vitro drug dissolution from the bilayer tablets was sustained for about 16 h after releasing 15% of drug in the first 10 min. The developed nimesulide bilayer tablets with improved efficacy can perform therapeutically better than the conventional tablets.
文摘The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was used for the optimization.Independent variables were extraction temperature,extraction pressure and entrainer flow rate.Dependent variable was yield ratio of icariin from Herba Epimedii.A two-order polynomial equation was fitted to the data.The results showed that the optimum extraction conditions were as follows:extraction temperature 46.5℃,extraction pressure 30.6 MPa,entrainer flow rate 3.3 mL/min.CCD/ RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.
基金Project(2012ZX04010-081) supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China
文摘To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental(CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model(RSM) was set up and the results of the analysis of variance(ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the "trial and error" procedure.
文摘Different multidisciplinary design optimization （MDO） problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the referred vehicle, three disciplines have been considered, which are trajectory, propulsion and aerodynamics. A special design structure matrix is developed to assist data exchange between disciplines. This design process uses response surface method （RSM） for multidisciplinary optimization of the rocket. The RSM is applied to the design in two categories： the propulsion model and the system level. In the propulsion model, RSM determines an approximate mathematical model of the engine output parameters as a function of design variables. In the system level, RSM fits a surface of objective function versus design variables. In the first MDO problem formulation, two design variables are selected to form propulsion discipline. In the second one, three new design variables from geometry are added and finally, an optimization method is applied to the response surface in the system level in order to find the best result. Application of the first developed multidisciplinary design optimization procedure increased accessible altitude （performance index） of the referred sounding rocket by twenty five percents and the second one twenty nine.
