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.

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.

Copper smelter slag treatment by ammonia solution:Leaching process optimization

The feasibility of copper smelter slag processing by ammonia solution treatment was investigated. The central composite rotatable design(CCRD) and approximation method were used to determine the optimum conditions of zinc and copper recovery to a solution. The experimental design was done at five levels of the four operating parameters which were the initial concentration of NH–3, the initial Cl ions concentration, leaching time and solid/liquid ratio. Two mathematical models describing dependence of metal recovery on the operating parameters were obtained. The models are successful in predicting the responses. It was found that optimal parameters for zinc and copper recovery are as follows(values for copper are given in brackets): initial CNH3 17.1%(19.9%), initial CCl– 160 g/L(160 g/L), leaching process duration 4.56 h(4.13 h), solid/liquid ratio 0.39(0.53). The maximum Zn and Cu recoveries to solution, obtained experimentally under the conditions, are 81.16% and 56.48%, respectively.

Optimization of compression formulation and load of food-grade tracers for grain traceability using central composite design

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.

Isolation of Cordyceps ophioglossoides L2 from Fruit Body and Optimization of Fermentation Conditions for Its Mycelial Growth

A strain isolated from the fruiting body of a fungus parasitized on Elaphomyces was identified as Cordyceps ophioglossoides based on the morphological characteristics and the analysis of ITS-5.8s rDNA sequence.The optimal medium composition(g·L-1),containing sucrose 66.0,yeast powder 10.0,silkworm chrysalises digest 30.0,MgSO4·7H2O 0.4,and KH2PO4 0.4,was found using fractional factorial design and a central composite design,and the optimization of cultural conditions obtained a result of seed age 6 days,inoculum size 6%(by volume),initial pH 5.6,temperature 24°C,shaking speed 160 r·min-1 by one-factor-at-a-time method.The maximum biomass reached about 20.2 g·L-1 after 90 hours culture under the optimal conditions.Elementary pharmacological activities showed that mycelia of C.ophioglossoides L2 from submerged culture promoted uterus growth in estrogendepleted mice.In the 15-litre scale-up fermentation,the mycelial biomass was around 19.1 g·L-1,indicating a promising prospect for this biotechnology and the potency to develop its medical value.

Improved elastase production by Bacillus sp. EL31410—further optimization and kinetics studies of culture medium for batch fermentation

An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K2HPO4, MgSO4·7H2O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, KEHPO4 0.206 g/100 ml and MgSO4·7H2O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth.

Activated Carbons Based on Shea Nut Shells (<i>Vitellaria paradoxa</i>): Optimization of Preparation by Chemical Means Using Response Surface Methodology and Physicochemical Characterization

In this study, shea residues (Vitellaria paradoxa) dumped in the wild by the units processing almonds into butter were used in the production of activated carbons. Shea nut shells harvested in the locality of Baktchoro, West Tandjile Division of Chad were used as a precursor for the preparation of activated carbons by chemical activation with phosphoric acid (H3PO4) and sulphuric acid (H2SO4). Central Composite Design (CCD) was used to optimize the preparation conditions, and the factors used were concentration of activating agent (1 - 5 M), carbonization temperature (400°C - 700°C) and residence time (30 - 120 min). The studies showed that at optimal conditions the yield was 51.45% and 42.35%, while the iodine number (IN) was 709.45 and 817.36 mg/g for CAK-P (phosphoric acid activated carbon) and CAK-S (sulphuric acid activated carbon) respectively. These two activated carbons (ACs) which were distinguished by their considerable iodine number, were variously characterized by elementary analysis, pH at the point of zero charge (pHpzc), bulk density, moisture content, Boehm titration, Fourier transform infrared spectroscopy, BET adsorption and scanning electron microscopy. These analyses revealed the acidic and microporous nature of CAK-P and CAK-S carbons, which have a specific microporous surface area of 522.55 and 570.65 m2·g−1 respectively.

An Optimization Study of α-Amylase Production by Aspergillus niger ATCC 16404 Grown on Orange Waste Powder

In this work, sequential optimization strategy, based on statistical designs, was employed to enhance the production of α-amylase by Aspergillus niger ATCC 16404. This statistical study consists of optimizing the factors that influence the production of α-amylase of A. niger ATCC 16404. Indeed, another statistical study has allowed the selection of 5 factors (pH, starch, yeast extract, “corn steep liquor”, CaCl2 and salts) affecting both the development of mould (biomass) and that of the enzyme production. The central composite design allows the determination of the optimum of these selected factors and a quadratic model explains the factor reaction. Thus, the “ridge analysis” method, has led to maximizing the experimental reaction. The results indicate that the production rate of α-amylase is maximized in the presence of starch at 8.97 g/l, yeast extract at 2.86 g/l, CaCl2 at 1.224 g/l, salts (composed of 25% FeSO4, 7H2O, 25% MnSO4 and 50% MgCl2, 6H2O): FeSO4, 7H2O, MnSO4 0.1518 g/l and MgCl2, 6H2O at 0.3036 g/l. As for the pH, it is maintained at the rate of 5.68.

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.

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.

Optimization of Process Parameters for in High-Energy Ball Milling of CNTs/Al2024 Composites Through Response Surface Methodology

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.

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.

骨伤跌打康复凝胶贴膏剂处方优选

目的优选骨伤跌打康复凝胶贴膏剂处方。方法以制剂的初黏力、持黏力、综合感官评分的归一化值为评价指标,以聚丙烯酸钠、甘羟铝、聚维酮K90、酒石酸、甘油、中药粉用量为影响因素,采用Plackett-Burman试验和星点设计-响应面法优选制剂处方,并验证。结果该凝胶贴膏剂制备工艺的关键因素为聚丙烯酸钠、甘羟铝、聚维酮K90的用量,最优处方配比为聚丙烯酸钠5.5 g、聚维酮K902.9 g、甘羟铝0.2 g。制得3批制剂的平均归一化值为0.8044,与理论值(0.817)接近(RSD为1.90%)。结论优化处方后的制剂外观均匀,黏性良好,符合凝胶贴膏剂的质量要求。

基于温度场仿真的塑料感应焊接工艺参数优化

特种热塑性工程塑料的应用对高端制造领域的轻量化、高性能化和环保化起着极其重要的作用。为了研究塑料与金属的感应焊接过程,更好地理解该过程中不同工艺参数对焊接金属表面温度的影响,并探索最适合的塑料感应焊接工艺参数,利用有限元仿真软件ANSYS Maxwell进行电磁场模拟,采用中心复合设计方法完成塑料感应焊接工艺参数方案设计,再通过该有限元仿真软件求解出相应的金属表面温度。基于多元非线性理论,建立了电流强度、电流频率、焊接间隙与金属表面平均温度之间的多元非线性回归模型。采用逐步回归的迭代策略,分析了各工艺参数以及各工艺参数交互作用对金属表面平均温度的影响程度。结果表明:二次拟合模型具有最佳的拟合度,决定系数R^(2)=0.956;电流强度是对金属表面平均温度影响最大的主效应,电流强度与焊接间隙的交互作用是影响金属表面平均温度的主要交互效应;基于该二次拟合模型,在该有限元仿真软件上进行了工艺参数优化并预测了多组最佳工艺参数组合,其仿真试验结果与回归分析结果误差在7%以内,说明该二次拟合模型预测结果准确可靠。相关理论和方法可为塑料在汽车、船舶、航空、航天等高端制造领域的应用提供参考。

Optimization on selenium and arsenic conversion from copper anode slime by low-temperature alkali fusion process

A process was proposed to convert and separate selenium and arsenic in copper anode slime(CAS) by low-temperature alkali fusion process.Central composite design was employed to optimize the effective parameters,in which Na OH/CAS mass ratio,fusion temperature and fusion time were selected as variables,and the conversion ratio of selenium and arsenic as responses.Second-order polynomial models of high significance and 3D response surface plots were constructed to show the relationship between the responses and the variables.Optimum area of >90% selenium conversion ratio and >90% arsenic conversion ratio was obtained by the overlaid contours at Na OH/CAS mass ratio of 0.65-0.75,fusion temperature of 803-823 K and fusion time of 20-30 min.The models are validated by experiments in the optimum area,and the results demonstrate that these models are reliable and accurate in predicting the fusion process.

Media optimization for extracellular amylase production by Pseudomonas balearica vitps19 using response surface methodology

BACKGROUND： In this study, we optimized the process for enhancing amylase production from Pseudomonas balearica VITPS 19 isolated from agricultural lands in Kolathur, India. METHODS： Process optimization for enhancing amylase production from the isolate was carried out by Response Surface Methodology （RSM） with optimized chemical and physical sources using Design expert v.7.0. A central composite design was used to evaluate the interaction between parameters. Interaction between four factors - maltose （C-source）, malt extract （N- source）, pH, and CaCl2 was studied. RESULTS： The factors pH and CaCl2 concentration were found to affect amylase production. Validation of the experiment showed a nearly twofold increase in alpha amylase production. CONCLUSION： Amylase production was thus optimized and increased yield was achieved.

Optimization of Hot Water Temperature Dipping and Calcium Chloride Treatment to the Selected Physico-Chemical Parameters of Keitt Mango and Cavendish Banana Fruits

Mango (Mangifera indica L.) and banana (Musa acuminata) are the most popular fruits in the world and widely cultivated crops in the tropical and subtropical zones. Keitt mangoes and Cavendish bananas are the largest cultivar of these fruits found in the Mozambique market. They are only available for a short period each year mostly during the late summer and early falls. Due to mango and banana fruits high water activity and respiration rate, are perishable foods and require conservation methods for preservation and availability. The aim of this study was to optimize the hot water-calcium chloride concentration treatment regime for improved postharvest handling of mangoes and bananas. The fruits collected were of uniform size, and at greenyellowish maturity stage based on length, diameter, colour and firmness. The process was optimized by experimental central composite design using hot water temperature (50°C - 60°C) and calcium chloride concentration (2% - 4%) with the aid of desirability function. The samples were analyzed for the centesimal composition, firmness, colour, °Brix, Aw, pH, titratable acidity and vitamin C. The results showed that hot water temperature and calcium chloride concentration were influent on the Keitt mangoes b* colour attribute, pH and titratable acidity as well as the Cavendish bananas firmness, ash and vitamin C content. The optimal conditions of the process were stabilized with the desirable function and, coincidentally for both crops, obtained at 55°C of hot water temperature dipping and 3% of calcium chloride concentration. The simulated data were similar to the experimental ones. This is the first time that calcium chloride-hot water treatment is being reported as a means of extending the shelf-life of mangoes and bananas.

Optimization of the Impeller Geometry for an Automotive Torque Converter Using Response Surface Methodology and Desirability Function

Response surface methodology (RSM) based on desirability function approach (DFA) is applied to obtain an optimal design of the impeller geometry for an automotive torque converter. The relative importance of six design parameters including impeller blade number, blade thickness, bias angle, scroll angle, inlet angle and exit angle is investigated using orthogonal design approach. The impeller inlet angle, exit angle and bias angle are found to exert the greatest influence on the overall performance of a torque converter, with two flow area factors being considered, namely 17% and 20%. Then, RSM together with central composite design (CCD) method is used to in-depth evaluate the interaction effect of the three key parameters on converter performance. The results demonstrate that impeller exit angle has the strongest impact on peak efficiency, with larger angles yielding the most favorable results. The stall torque ratio maximization is attainable with the increase of impeller bias angle and inlet angle together with smaller exit angle. In the end, an optimized design for the impeller geometry is obtained with stall torque ratio and peak efficiency increased by 1.62% and 1.1%, respectively. The new optimization method can be used as a reference for performance enhancement in the design process of impeller geometry for an automotive torque converter.

基于AHP-CRITIC混合加权法和星点设计-效应面法的荆防活血乳膏处方优化研究

目的研究并优选荆防活血乳膏剂的制备工艺。方法以荆防活血乳膏剂的离心稳定性、耐热稳定性、涂抹分散性为考察指标,采用层次分析法(AHP)、基于指标相关性的权重确定方法(CRITIC)、AHPCRITIC混合加权法确定各评价指标的权重系数,并结合星点设计(central composite design,CCD)-效应面优化法筛选荆防活血乳膏处方中出对基质质量影响较大的3个因素硬脂酸、甘油、混合乳化剂(平平加、三乙醇胺)的用量,验证优化后的最佳处方。结果按AHP-CRITIC混合加权法得到离心稳定性、耐热稳定性、涂抹分散性的权重系数分别为0.5216,0.3372,0.1412,最佳处方比例为:硬脂酸4.4 g,甘油14.3 g,混合乳化剂4.2 g,单硬脂酸甘油酯2 g,凡士林8.5 g,二甲基硅油10 g,纯化水20 g,冰片1.5 g(2%),苯甲酸钠0.1%,荆防活血方组方药物提取干膏用量7.5 g(每100 g乳膏中含主药量约10 g)。结论优选出的荆防活血乳膏剂制备工艺经验证简单、合理,所得制剂具有良好的外观性状、涂抹分散性和稳定性。