Plackett-Burman和Central Composite Design试验设计法优化石榴皮中熊果酸的SFE-CO_2萃取工艺

目的:探讨应用SFE-CO2萃取石榴皮中熊果酸的最佳工艺。方法:以熊果酸得率为考察指标,通过Plackett-Burman(PB)试验设计筛选影响熊果酸得率的显著性因素,最陡爬坡试验逼近熊果酸得率最大区域,Central Composite Design(CCD)试验设计对显著性因素进行响应面优化得到影响熊果酸得率的二阶数学模型,进而得出最佳工艺条件。结果:SFE-CO2萃取石榴皮中熊果酸的最佳工艺条件为:萃取温度46.29℃,萃取时间91.6 min,萃取压力34.49 MPa,在此条件下,验证试验测得熊果酸得率为12.508 mg/g,与模型预测值12.645 mg/g接近。结论:将PB试验和CCD试验设计联合应用于优化石榴皮中熊果酸SFE-CO2萃取工艺,筛选结果具有统计学意义,工艺操作具有可行性。

Analysis of Heat Transfer Performance of Oscillating Heat Pipes Based on a Central Composite Design

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.

Application of response surface methodology and central composite rotatable design for modeling the influence of some operating variables of the lab scale thickener performance

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.

Modeling and Optimization of Catalytic Dehydration of Ethanol to Ethylene Using Central Composite Design

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.

Optimization of Extraction Process of Clerodendrum philippinum Schauer var. simplex Mlodenke Total Flavonoids(CPTF) by Central Composite Design-Response Surface Methodology

[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.

Calibration of Discrete Element Heat Transfer Parameters by Central Composite Design

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.

Modeling of biodiesel production: Performance comparison of Box–Behnken, face central composite and full factorial design

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.

Extraction Process Optimization of Total Flavonoids from Mallotus apelta Stems by Central Composite Design/Response Surface Method

[Objectives] To optimize the extraction process of total flavonoids in stems of Mallotus apelta. [Methods]On the basis of singlefactor test,with volume fraction of ethanol,extraction time and ratio of solvent as independent variables,the content of total flavonoids as dependent variables,the completely secondary response surface regression fitting was conducted on the independent and dependent variables,and the Response Surface Method was used to optimize the optimum extraction process of total flavonoids in Mallotus apelta stems and predict the optimum process. [Results] The optimum extraction process of total flavonoids in Mallotus apelta was determined as follows: ethanol concentration of 71. 5%; extraction time of 154. 6 min; solid-liquid ratio of 1∶19. 2; total flavonoids content of 7. 060 mg/g; fitted binomial squared correlation coefficient R^2= 0. 8751.[Conclusions]Composite Design/Response Surface Method could be used in the extraction process optimization of total flavonoids in Mallotus apelta stems,the mathematical model established had high prediction accuracy,the method was simple and operability was good.

Optimization of extraction technology of safflower polysaccharide based on central composite design-response surface methodology

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.

Optimization of Extraction Process of Total Flavonoids from Akebia trifoliata (Thunb.) Koidz. by Central Composite Design-Response Surface Methodology

[Objectives]To optimize extraction process of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,so as to provide references for development and use of Akebia trifoliata( Thunb.) Koidz. [Methods]The extraction rate of total flavonoids of Akebia trifoliata( Thunb.)Koidz. was taken as observation indicator. On the basis of single factor experiment,central composite design( CCD) was used to evaluate the effects of the extraction temperature,extraction time,and ethanol concentration on the extraction process. Multiple linear regression and binomial fitting were used,and response surface methodology( RSM) was used to select the optimum extraction process. [Results] The optimum extraction process conditions for total flavonoids of Akebia trifoliata( Thunb.) Koidz. was extraction temperature: 83. 92 ℃; extraction time:96. 47 min; ethanol concentration: 63. 92%; extraction times: two times; solid to liquid ratio: 1 ∶ 20; extraction rate of total flavonoids:4. 55%. [Conclusions] The central composite design-response surface methodology( CCD-RSM) is simple,convenient,and feasible for extraction of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,and the prediction results are reliable.

Central Composite Design Method for the Preparation, Stability and Properties of Water-in-Diesel Nano Emulsions

Water in diesel nano-emulsion (WiDNE) due to their nano size, kinetically stable gives its beneficial in commercial and environmental aspects. However, the capability of this fuel strongly depends on the method of preparation, stability and their physic-chemical properties. Central composite design (CCD) method was used to optimize variable interactions in order to obtain maximum stability. Methodology RSM method with six independent variables was selected in order to understand the impacts on droplet size. The response surface and 3D plots of the quadratic polynomial model were created for studying the combination effect on response. Dynamic light scattering DLS technique was used for measuring of droplet sizes. The analysis result by ANOVA was with 95% confidence displaying F value model was 52.82. The results displayed model was fulfilled with the assumptions of ANOVA. This study has relied on Design Expert software to locate the optimum droplet size situations. The measured diameter is 26 nm, with 0.0297 errors between actual conditions and measured value. The optimum blend properties of prepared WiDNE fuel were compared with conventional diesel. Improvements in physical properties were observed in presence of water in WiDNE.

Central-Composite Design响应面实验设计用于金盏菊提取工艺的研究

目的:确定金盏菊最佳提取工艺条件。方法:以金盏菊中总黄酮含量及浸膏得率为考察指标,应用中心组合(Central composite design,CCD)响应面实验设计,考察药材与提取溶剂的比例(料液比)、乙醇浓度、提取时间对金盏花提取效率的影响。结果:根据二项式拟合方程,确定金盏花最佳提取工艺条件为药材与溶剂的比例为1∶12,乙醇浓度为68%,提取时间为1.8 h,提取两次。结论:中心组合响应面实验设计能够对金盏菊的提取工艺进行优化筛选。

Central Composite Design响应面法优化厚裂凤仙花总黄酮提取工艺研究

为厚裂凤仙花中总黄酮资源的开发利用,本文采用单因素与星点-效应面法相结合的方式,考察提取溶剂浓度、料液比、提取时间、提取次数对厚裂凤仙花中总黄酮提取率的影响。优选出厚裂凤仙花总黄酮最佳提取方法为:甲醇体积分数80%,料液比为1︰64,提取时间为50 min;提次数为3次;验证实验结果表明,总黄酮平均提取率为5.51 mg/g,与实验模型RSD值为0.79%。建立的模型与实际方案有较高拟合度,可作为苗药厚裂凤仙花总黄酮提取工艺参数。

Elaboration of a Promising Design of the HTS Conductor for the Central Solenoid of a Compact Thermonuclear Reactor TRT

The results of the preliminary development of the HTS conductor based on the VS-type design and parallel stacks for the central solenoid of the compact thermonuclear reactor TRT are presented. One of the main problems that need to be solved for the successful implementation of such projects is the creation of high-current high-temperature superconducting (HTS) conductors for Toroidal Field coils (TF) and Central Solenoid (CS) sections. The conductor must have a high engineering current density of at least 90 A/mm2. The induction of the magnetic field in the central solenoid reaches 14 T, which leads to the occurrence of large mechanical stresses due to the influence of Lorentz forces. Like many large magnets, CS has a lot of stored energy. For the safe withdrawal of stored energy from the magnet, it requires the inclusion of elements in the conductor that provide an acceptable level of electrical voltage and heating of the conductor insulation. Thus, a sufficient amount of stabilizing and reinforcing materials should be placed in the conductor. In addition, the “cable-in-conduit” type of conductor must have channels for pumping the refrigerant. Two fundamentally different versions of the conductor based on radially arranged REBCO tapes and on the basis of pre-assembled tape packages are considered. Based on the analysis of the magnetic field distribution in the conductor by finite element method, the design characteristics of the proposed conductors under various operating modes of the electromagnetic system (EMS) of the tokamak TRT was evaluated. The results of the evaluation of the current carrying capacity of the conductor and the estimation of energy losses in a changing magnetic field in comparison with known methods are also presented.

Six-Element Yagi Array Designs Using Central Force Optimization with Pseudo Random Negative Gravity

A six-element Yagi-Uda array is optimally designed using Central Force Optimization (CFO) with a small amount of pseudo randomly injected negative gravity. CFO is a simple, deterministic metaheuristic analogizing gravitational kinematics (motion of masses under the influence of gravity). It has been very effective in addressing a wide range of antenna and other problems and normally employs only positive gravity. With positive gravity the six element CFO-designed Yagi array described here exhibits excellent performance with respect to the objectives of impedance bandwidth and forward gain. This paper addresses the question of what happens when a small amount of negative gravity is injected into the CFO algorithm. Does doing so have any effect, beneficial, negative or neutral? In this particular case negative gravity improves CFO’s exploration and creates a region of optimality containing many designs that perform about as well as or better than the array discovered with only positive gravity. Without some negative gravity these array configurations are overlooked. This Yagi-Uda array design example suggests that antennas optimized or designed using deterministic CFO may well benefit by including a small amount of negative gravity, and that the negative gravity approach merits further study.

复方麝香黄芪滴丸成型工艺优选及挥发性成分含量测定

目的优选复方麝香黄芪滴丸成型工艺,并完善该复方的质量标准。方法通过单因素实验筛选复方麝香黄芪滴丸的基质种类、基质和药液比例、滴距的最佳考察范围;以外观性状、丸重差异、溶散时限等作为评价指标,采用星点设计-效应面法优选复方麝香黄芪滴丸最佳成型工艺条件;以3批复方麝香黄芪滴丸为检测样品,采用气相色谱法测定龙脑、麝香酮和藁本内酯含量;色谱柱为HP-5石英毛细管柱,进样口温度260℃,程序升温,检测器温度300℃,分流比10:1,载气为氮气,流速为1.0 mL·min^(-1)。结果复方麝香黄芪滴丸的最佳成型工艺条件为基质:基质=0.99、药物:基质=0.55、滴距=6.00,综合评分为0.8452;龙脑、麝香酮和藁本内酯与相邻成分色谱峰均达到基线分离;3种成分的线性范围依次为0.327~1.962、0.140~0.840、0.7105~4.263μg(均r>0.999);平均加样回收率依次为92.30%(RSD=1.65%,n=6)、101.28%(RSD=0.81%,n=6)、98.99%(RSD=0.65%,n=6);3种成分的平均含量依次为0.2017、0.0847、1.3829 mg·g^(-1)。结论该成型工艺稳定可行,可为复方麝香黄芪滴丸的开发及应用提供参考;建立的气相色谱法能同时测定复方麝香黄芪滴丸中龙脑、麝香酮和藁本内酯的含量,可用于复方麝香黄芪滴丸的质量控制。

定点零售药店参与集中采购与集中结算研究

当前,零售药店参与集中采购的积极性不高。对此,基于现有的药品集中采购经验,提出零售药店集中采购的两种新模式——零售药店联盟开展集中带量采购和自主联合开展集中带量采购,并总结新模式采购流程、采购方式、采购特点、供应保障、集中结算等方面特点。零售药店参与集中采购、集中结算能够在一定程度上规范药品价格形成,但目前存在处方流转难、采购品种供需不匹配的问题,应完善处方流转机制,增强对零售药店采购行为和医保基金使用行为的管控,确保医保基金安全有效运行。

黄芩提取物磷脂复合物自微乳给药系统的制备与体外释放度评价

目的:基于磷脂复合物(PC)研究黄芩提取物(BA)自微乳给药系统(SMEDDS)的处方设计及制备工艺,并进行体外质量评价。方法:以BA-PC为中间体,通过溶解度实验、绘制伪三元相图和星点设计-效应面法确定BA-PC-SMEDDS的最佳处方;优化制备工艺并对其理化性质、稳定性、体外释放度进行评价。结果:BA-PC-SMEDDS最优处方为油酸乙酯为油相,吐温-80为乳化剂,二乙二醇单乙醚为助乳化剂;油相质量分数14.39%,Km值2.71,为简化处方,将处方修定为油相质量分数14.5%,混合乳化剂Km2.7;平均粒径为(16.83±0.04)nm,多分散系数(PDI)为(0.127±0.002),Zeta电位为(-12.02±0.03)mV,载药量为(16.75±0.09)mg/g;BA-PC-SMEDDS在pH为1.2、5.0、7.4的缓冲盐溶液中具有良好的体外释放效果。结论:BA-PC-SMEDDS粒径小,载药量高,外观良好,性质稳定,提高了难溶性成分黄芩苷的溶解度及体外释放度,具有增加口服生物利用度的潜力。

Effect of Variable Selection on Multidisciplinary Design Optimization:a Flight Vehicle Example

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.

Steam Pretreatment of Rice Hulls to Release Fermentable Saccharides:An Approach to Improve Recovery of(Hemi)Cellulosic Sugars Through Multivariate Design

The conversion of rice hulls into fermentable saccharides was explored through steam pretreatment employing 2.5% SO_(2).The in teraction between temperature and time was assessed by means of the response surface method to achieve optimum contents of C6-sugars in water-insoluble solids(WIS)and C5-sugars in the liquor.Pretreatment carried out at 218℃ for 2.3 min released liquor containing 55.4 g/L of sugars(29.1 g/L of xylose).In parallel,the WIS was subjected to enzymatic saccharification using different solid and enzyme loads via an experimental design:assays using 22.0% WIS and 20.0 filter paper units(FPU)/g led to 90.6 g/L of glucose,corresponding to a yield of 86.4% and an overall yield of 72.4%.The data reported are the highest ever found for such raw material,making it attractive to compete with conventi on al lig no cellulosic biomass.