Probabilistic analysis of ultimate seismic bearing capacity of strip foundations

This paper presents a reliability analysis of the pseudo-static seismic bearing capacity of a strip foundation using the limit equilibrium theory. The first-order reliability method (FORM) is employed to calculate the reliability index. The response surface methodology (RSM) is used to assess the Hasofer–Lind reliability index and then it is optimized using a genetic algorithm (GA). The random variables used are the soil shear strength parameters and the seismic coefficients (k_h and k_v). Two assumptions (normal and non-normal distribution) are used for the random variables. The assumption of uncorrelated variables was found to be conservative in comparison to that of negatively correlated soil shear strength parameters. The assumption of non-normal distribution for the random variables can induce a negative effect on the reliability index of the practical range of the seismic bearing capacity.     

Optimization of Ozonation Process for a Composting Leachate-Contaminated Soils Treatment Using Response Surface Method

The ozonation process has become one of the most favorable processes among soil remediation technologies nowadays. Ozone, which has an oxidation potential of 2.07 V and acts as a powerful oxidizer, is capable of degrading organic pollutants of soil in a short period of time without producing any toxic residuals. In this study the capability of ozone, as an ex-situ method of soil treatment, in remediating the leachate-contaminated soil has been investigated. To maximize the removal efficiency of organic content of soil, design of experiments using the response surface method (RSM) and central composite design (CCD) have been employed. To select the range of effective parameters several experiments were performed at laboratory scale. Results showed a range of effective parameters on the ozonation process, including pH, humidity, and initial soil pollution. Present research shows that acid-washed ozone greatly enhanced the removal efficiency. According to the developed model, the maximum removal efficiency using acid-washed ozone was obtained by setting the parameters as pH = 10.8, humidity of 5% and initial organic content of soil to be 7720 mg/kg. Confirmation experiments showed that RSM could be effectively utilized for the optimization of the ozonation process. Analysis of variance also showed that pH was the most significant factor affecting removal efficiency.     

响应曲面优化法合成聚丙烯酰胺类共聚物

采用响应曲面优化法(Response surface methodology)以丙烯酰胺(AM)和二甲基二烯丙基氯化铵(DMDAAC)为共聚单体,通过自由基聚合对聚丙烯酰胺类共聚物(PDA)进行制备研究。探讨了3个主要因子单体摩尔比、聚合体系p H、引发剂用量的最佳水平及各自变量间的交互作用对PDA得率的影响,通过该法设计得到了最佳优化条件:单体摩尔比n(AM)∶n(DMDAAC)=2.5∶1,聚合体系p H6.00,引发剂用量为单体总质量的1.00%。在模型提供的最优水平下PDA得率89.807%,与预测值91.6944%相吻合,表明所选模型准确、可靠。该方法为聚丙烯酰胺类共聚物的合成及应用提供了依据。     

基于响应面的天然气三甘醇脱水装置用能优化

运用流程模拟软件HYSYS建立三甘醇(TEG)脱水装置的工艺模型,选择循环量qV、再生温度tr和三甘醇富液进塔温度ti作为主要参数,基于响应面方法(RSM)建立脱水装置能耗的二次显式模型。对响应面模型的显著性和三维图进行分析,结果表明:循环量、再生温度和富液进塔温度对装置能耗影响显著,影响程度为:循环量富液进塔温度再生温度;在对能耗的共同影响中,循环量和再生温度、循环量和富液进塔温度交互作用显著而再生温度和富液进塔温度间交互作用可以忽略。以吸收塔出口气体水露点满足GB17820—2012为约束条件,对模型进行最优化求解得到最优操作条件为:循环量400 L/h、再生温度199.8℃、富液进塔温度130℃,在此条件下理论能耗可下降48.3%,具有显著的节能效果。     

循环旋风分离器内气液两相流动数值模拟

采用雷诺应力模型RSM对循环旋风分离器内气液两相流动的情况进行了数值模拟研究,讨论了循环旋风分离器内切向速度、轴向速度、径向速度、压力场、雷诺应力的分布特点以及相同入口速度下分离器内液滴运动轨迹与分离器的分离效率。数值模拟结果表明,循环旋风分离器切向速度呈现明显的驼峰状,轴向速度上行流和下行流明显,径向速度相对较小,压力由轴心向外逐渐升高,雷诺应力分布复杂且无明显规律,分离器对小直径液滴分离效率较低,入口速度对分离效率的影响比较明显。     

径向入口结构的旋风分离器内三维流场的数值研究

采用雷诺应力模型(RSM)对径向入口结构的旋风分离器内气相流场进行了数值模拟。不同于传统的切向入口结构,径向入口设计使得新型旋风分离器在保证较高分离效率的同时更能适应高压下的作业,且降低了工程焊接难度。通过模拟结果与实验值的对比发现,RSM模型能很好地预测新型旋风分离器内部气相流场,且模拟结果表明:旋风分离器内部流场呈现非轴对称性,主要表现为沿轴向气流的旋转中心与旋风分离器的几何中心不重合,且在分离空间内各轴截面出现具有周期性的摆动涡核。分离空间内切向速度场以0.8倍升气管直径为边界,呈现自由涡与强制涡结合的兰金涡形式,随着入口角度和升气管直径比(dr=dr/D)的减小,切向速度增大,内外旋流区也随之变化。此外,升气管内切向速度呈"U"形分布,由于速度分布中心不断发生变化,亦存在摆动涡核且摆动频率较分离空间的大。     

应用响应面法分析絮凝效果

利用响应面法（RSM）分析聚合氯化铝（PAC）和新生态二氧化锰（MnO2）在不同投配比,相同配水和水力条件下的最佳絮凝效果。主要考察了絮凝反应后的浊度去除率、沉淀结束后的浊度去除率和颗粒总数去除率。通过RSM法计算得到聚合氯化铝（PAC）和新生态二氧化锰（MnO2）的最佳投药范围。     

组合实验设计用于黄曲霉毒素污染控制的研究

为控制黄曲霉毒素主要产生菌寄生曲霉 AS3.4407在粮食储藏环境中的产毒污染,采用组合实验设计策略,考察了五个模拟环境因子对菌株产毒的影响。首先,利用 Plack-ett-Burman 试验筛选出三个对毒素产量影响显著的因子(转速、温度、pH),在此基础上,采用CCD 实验设计法(Central Composite Design,CCD)研究了这三个因子对寄生曲霉 AS3.4407产毒影响的交互作用,并根据毒素曲面方程和二次多项回归方程得到该菌的最低产毒条件。在环境通风良好(转速240rpm),储藏温度较低(18℃),pH 为弱碱性(pH8)条件下,寄生曲霉AS3.4407产毒量最低,验证试验证实了该方程的预测值与实际值之间具有较好的拟合度。为粮库采取相应措施,改变储藏环境条件以降低毒素污染提供了很好依据。     

Linear Programming and Response Surface Methodology to Optimize Surimi Gel Texture

A formulation optimization study was conducted on surimi gels prepared with starch, and/or raw egg white employing the stepwise method (SM), linear programming (LP), and response surface methodology (RSM). At 78% moisture, the greatest gel strengthening and reduction of expressible moisture occurred at 8% starch, 6% egg white, or a combination of 5% starch and 5% egg white for SM, 5.33% starch and 4.33% egg white for LP, and 3.5% starch and 5% egg white for RSM. RSM resulted in gels with the greatest strength (compressive and penetration forces), followed by LP and SM. The RSM enabled more accurate prediction of textural behavior of final product at various ingredient combinations than the SM or LP.     

酶法水解牛胎盘下脚料

以牛胎盘下脚料为原料，试验5种蛋白酶对其进行水解，根据水解液综合效果确定中性蛋白酶为最适单酶，其最佳水解条件为温度40℃，pH7．5，酶添加量4000u／g，料水比1：3，水解时间4h；响应面分析方法知，中性蛋白酶与胰蛋白酶混合水解牛胎盘下脚料的最佳水解条件为：温度46．4℃，pH值为8．17，酶比1：1(酶量为4000u／g)，料水比为1：3。氨基酸分析结果表明：混合酶水解液的游离氨基酸2483.6mg／L，而中性酶水解液的游离氨基酸493.8mg／L。