β-聚苹果酸/明胶微胶囊的制备

文章对β-聚苹果酸(β-poly malic acid,β-PMA)和明胶(gelatin)通过复凝聚法制备微胶囊进行了描述.在常温常压下,通过Plackett-Burman设计得出主要的影响因素是β-PMA和明胶的浓度、明胶的pH、反应时间.根据Box-Behnke设计得出了较好的制备条件,在该模型下优化得出的最佳条件为:PMLA浓度0.1％,明胶浓度0.13％,明胶pH4.0,反应时间25min时,微胶囊粒径为288.37nm.     

杜仲籽油混合脂肪酸制备工艺优化及脂肪酸组成分析

以杜仲籽油为原料,在常压下皂化水解并用正己烷萃取制备杜仲籽油混合脂肪酸.在单因素超碱量、KOH-乙醇溶液/油的比例、皂化温度、皂化时间和酸化pH研究的基础上,选取超碱量、皂化温度、皂化时间和酸化pH四个因素,应用响应面设计中的Box-Behnken设计对皂化工艺进行优化并得到回归模型,通过气质联用仪分析杜仲籽油脂肪酸的组成.结果表明,制备杜仲籽油混合脂肪酸的优化工艺条件为:超量碱52％,皂化温度77℃,皂化时间82min,酸化pH2.7,在此优化条件下,测得混合脂肪酸的酸值为159.19mg KOH/g.气质联用仪分析结果显示杜仲籽油混合脂肪酸中α-亚麻酸的相对含量可达60.14％,可以作为进一步分离提取杜仲籽油α-亚麻酸的原料.     

A Comparative Study on a Vertical Stirred Mill Agitator Design for Fine Grinding

Comminution is an energy intensive process. A small change in efficiency can lead to substantial benefits in an overall economy of the process plant. This study focused on the comparison of vertical stirred mill agitator designs. A double helical screw agitator was designed for this purpose. A series of stirred mill experiments were performed with two types of agitator designs a standard pin type and CSIRO’s designed double helical screw stirrers. The effects of operating parameters such as grinding time, stirrer speed, and pulp density on grinding performance was investigated using a magnetite concentrate. Grinding performance was analyzed by considering the product fineness and the energy consumption. The test results show that the grinding time and stirrer speed played a significant role; however, the pulp density had little impact on grinding performance in both cases of agitator designs. The 80% passing target product size of 38 μm was obtained with double helical screw agitator in 20 min of grinding with an expend of 10.53 kWh/t specific energy, whereas, the target product size of 38 μm was achieved with the pin type stirrer at the rate of 21.73 kWh/t. It is evident that grinding in a vertical stirred mill with a double helical screw is more efficient than that using a pin type stirrer in terms of the product size distribution and the specific energy consumption. It is concluded that the double helical screw design provides better energy efficiency compared to the pin type stirrer design. The models were developed for the responses P₈₀ and E_cs. Both models show high regression coefficients thus ensuring a satisfactory of models with experimental data. The model equations developed were then optimized using a quadratic programming to minimize the P₈₀ size at minimum specific energy.     

响应面法优化P.acidipropionici产酸发酵培养基

利用响应面分析法优化产酸丙酸杆菌发酵产酸培养基.在单因素试验的基础上,采用Box-Behnken试验设计,选定甘油、混合氮源(酵母提取物:胰酶大豆肉汤=2∶1)和磷酸氢二钾3个关键因子为响应因子,以丙酸产量为响应值建立多元二次回归方程,在分析各个因素的显著性和交互作用后,确定了产酸丙酸杆菌发酵产酸的最优培养基为:甘油44.4g/L、混合氮源(酵母提取物:胰酶大豆肉汤=2∶1)27.0g/L、K2HPO4 2.0g/L,丙酸产量最大预测值为20.75g/L.经过优化,丙酸产量提高了151％,实验值与预测值基本相符.     

利用Box-Behnken法分析CO2置换CH4效果

基于CO2置换CH4理论,综合考虑影响CO2置换CH4效果的3个因素,运用Box-Be-hnken实验设计方法,建立CO2置换CH4的数学模型。通过Design Expert软件生成曲面反应图,并对曲面反应图进行单因素及双因素解吸效果分析,得出各参数对CO2置换CH4效应影响的强弱顺序及交互影响的显著性,其结果依次为渗透率、含水率、含气量,进而对CO2置换CH4效果进行分析。该研究为煤层气提高采收率提供了一个省时有效的分析方法。     

Combination of Ozonation and Hydrogen Peroxide Bleaching for Linen Fabrics: Optimization of the Process Using Experimental Design Technique

It is well known that ozone can be used as a bleaching agent for cellulosic textile materials. In the context of this study, investigations were undertaken to optimize bleaching of linen fabrics using Box-Behnken Experimental Design. The bleaching process involved two distinct steps where linen fabrics were ozonated under different treatment times then the latter in a subsequent step were subjected to hydrogen peroxide bleaching under a variety of conditions. As a result of study, three optimum recipes were achieved and pretreatment with ozone for 15 min before peroxide bleaching supplies time and chemical savings.     

响应面法优化郫县豆瓣制曲工艺

本实验采用Box-Behnken法分析优化郫县豆瓣制曲工艺。在单因素试验的基础上,选取曲精量、制曲温度、制曲时间为响应因素,以成曲质量指标（蛋白酶活力和α-淀粉酶活力）综合评分为响应值,建立回归模型,并结合实际操作情况,得出郫县豆瓣最佳制曲工艺条件为：曲精量0.28%、制曲温度33.50 ℃、制曲时间32.50 h,此时成曲质量指标综合评分为98.23。     

红曲霉固态发酵产生淀粉酶培养基的优化

研究碳源、氮源、无机盐对红曲霉M2固态发酵产生淀粉酶的酶活性影响。在单因素试验的基础上,采用响应面试验设计对红曲霉固态发酵产生淀粉酶的培养基进行优化,并建立乳糖、(NH4)2SO4、K2HPO4变化的二次回归方程,探讨各因素对生淀粉酶酶活力的影响。在固态发酵基础培养基中,最终确定适宜的培养基条件为：乳糖添加量为8.18%、(NH4)2SO4添加量为6.36%、K2HPO4添加量为0.91%;在该条件下可得到红曲霉M2产生淀粉酶的最大酶活力,预测值为680.29 U/g,对实验结果进行验证,得到生淀粉酶酶活力为662.21 U/g。     

Optimization of microwave-assisted extraction for picroside I and picroside II from Picrorrhiza kurroa using Box-Behnken experimental design

The response surface methodology was employed to study the optimization of microwave-assisted extraction of picroside I and picroside II from Picrorrhiza kurroa Royle rhizomes. The effects of solid to solvent ratio, and extraction temperature, time and solvent on the yields of picroside I and picroside II have been investigated using Box-Behnken experimental design. The experimental data were fitted to second-order polynomial equations using multiple regression analysis and analyzed using the appropriate statistical method. By solving the regression equation and analyzing 3-D plots, the optimum extraction conditions were found to be: solid to solvent ratio, 10 : 90 (w/v); temperature, 60 °C; and extraction time, 60 s. Under the optimal conditions, the yields of picroside I and picroside II are 41.23 and 6.12 mg·g^–1 feed respectively, which are in good agreement with the predicted values. The ratio of solid to solvent significantly affects the yields of picroside I and picroside II. Application of microwave-assisted extraction of picroside I and picroside II from P. kurroa would dramatically reduce extraction time and solvent consumption.