Numerical analysis of the compressive and shear failure behavior of rock containing multi-intermittent joints

The failure behavior of intermittent jointed rocks is dependent on joint configurations. Joint inclination angle and continuity factor determined the joint arrangement in a rectangular numerical sample that was established by using the particle flow code approach. To identify the differences in the failure processes of identical intermittent jointed samples, uniaxial compressive and shear loads were applied on each sample. The crack growth path presented the four typical crack coalescence patterns identified via compressive and shear numerical tests. The crack coalescence pattern was associated with joint slant angle and continuity factor. The observed crack coalescence patterns of every sample with the same inclination angle and continuity factor were partially identical under compressive and shear loading. The differences in the crack patterns of the compressive and shear failure processes were described and compared. Typical compressive and shear failure processes were illustrated. Four compressive and three shear failure modes were identified. The cracking location and number of cracks in each failure mode were different. Additionally, the contact force evolution among particles during shear and compressive loading was different and likely accounted for the differences in cracking patterns. Under compressive or shear loading, the contact force concentration in each sample underwent the following stages: uniform distribution before loading, concentrated distribution, and scattered distribution after failure.     

肥胖儿童间歇性周期运动下的心肺耐力反应建模分析

当前对肥胖儿童间歇性周期运动下的心肺耐力反应建模分析方法,一般是在运动形式保持不变的情况下,搭建二维动态建模,无法准确给出间歇性周期运动对肥胖儿童的重要性,建模分析准确性较低,且有效性与实用性差。因此,提出准确性和有效性较高的肥胖儿童间歇性周期运动下的心肺耐力反应三维建模分析方法,利用该方法,在不同运动形式的情况下,对肥胖儿童间歇性周期运动下的心率、肺活量指数和最大摄氧量进行三维动态建模,给出三维动态建模分析式,确定间歇性周期运动对肥胖儿童心肺健康的重要性。实验通过对比分析方式,证明所提方法拥有较高的建模分析准确性和有效性。     

扬水曝气贫营养生物膜组合技术净化微污染原水中试研究

在扬水曝气条件下,模拟原位条件进行了贫营养生物膜技术净化微污染原水的试验研究,分析测定其对氮源污染物及有机污染物的去除效果。试验结果表明,扬水曝气-贫营养生物膜组合技术用于净化微污染原水是可行的;在水温为10~23 ℃,溶解氧浓度为4.0~6.0 mg/L、NH +4-N 0.230 mg/L、NO -2-N 0.010 mg/L、NO -3-N 1.125 mg/L、TN 2.010 mg/L、CODMn 3.140 mg/L、TOC 3.012 mg/L和BOD5 1.540 mg/L的条件下,系统稳定运行时的氨氮、硝氮、总氮及TOC去除率范围分别为82%~100%、62%~79%、71%~80%和73%~80%,亚硝氮已基本检测不到,BOD5/CODMn比值在0.05~0.20之间,说明该组合系统的脱氮效果可满足地表水环境Ⅲ类水体的质量标准要求,且生物稳定性可得到明显提高。另外,还考察了运行过程中生物膜上贫营养反硝化细菌数量及生物相的变化情况,并探讨了贫营养生物膜系统的净水机理。     

充气包装机及气体置换机理的研究

本文根据理想状态下气体方程式,导出了在密闭容器中按任意质量比例进行混合不同气体的计算公式,在此基础上设计了相应的执行机构,以确切实现气体置换的目的。     

浅谈污水生物处理AB法

介绍了AB法的由来,分析了AB法工艺的主要特征和处理机理,就该工艺的适用范围、优缺点以及发展方向进行了探讨。     

厌氧膜床-曝气生物滤池处理低浓度污水脱氮

通过日处理量为 5 0 0m3·d- 1的中试试验研究了影响厌氧膜床 (SAFB) -曝气生物滤池 (BAF)组合工艺处理低浓度生活污水脱氮性能的关键因子 :曝气量与进水水质 .发现在气水比大于 2∶1时 ,TN和NH4 + N的平均去除率分别为 2 7.84 %和 83.39% ;而在气水比小于 2∶1时 ,TN和NH4 + N的平均去除率分别为 2 9.15 %和 70 .88% ,所以组合工艺的气水体积比宜控制在 2∶1到 3∶1之间 .当SAFB进水的BOD5/TN比大于 4时 ,反硝化作用不受碳源影响 ;而当BAF进水的CODcr/TN比大于 5时 ,硝化作用受抑制 .     

Phytoremediation of industrial effluent containing azo dye by model up-flow constructed wetland

This study assessed the treatment of azo dye Acid Orange 7(AO7)containing wastewater by laboratory-scale up-flow constructed wetland(UFCW)with and without supplementary aeration.The supplementary aeration could effectively control the ratio of anaerobic and aerobic zones in the UFCW reactor.The results dearly show the supplementary aeration boosted the biodegradation of organic pollutants and mineralization of intermediate aromatic amines formed by AO7 degradation.     

文丘里曝气器布置对循环水体增氧效率的影响

为实现封闭循环水养殖系统中溶解氧的动态平衡,运用"对冲流动"理念与文丘里曝气器的自吸气增氧原理,设定15种工况,探究文丘里曝气器的对冲方式对水体增氧的影响.结果表明:氧体积传质系数与循环水体流量成正比;在同一流量条件下,氧体积传质系数与文丘里曝气器淹没深度成反比.结合增氧效果与对冲循环流场特性,建议在养殖初期与后期将文丘里曝气器安装为A—B层错层对冲,而在养殖中期调整为A—C层错层对冲.     

具有学习效应和遗忘效应的间歇批生产的单机排序问题

本文研究具有Dejong学习效应和遗忘效应的间歇批生产的单机排序问题,考虑了批与批之间没有学习效应的传递、有部分学习效应的传递和有总的学习效应传递的三种模型.对目标函数为最大完工时间的情形,指出机器在批与批之间没有学习效应的传递和有部分学习效应传递的情形下是多项式可解的,并进一步对机器在批与批之间有总的学习效应传递的两种特殊情形给出了多项式时间算法.     

RBF methods for solving laterally averaged Saint Venant equations: application to eutrophication prevention through aeration

A vertical 2D_xz laterally averaged hydrodynamic model is presented in this paper to study the aeration process in lakes. The system exhibits highly nonlinear behaviour due to the phenomena involved such as stratification, air concentration, and convective terms. The suggested model is used to simulate mechanical aeration to overcome and prevent the eutrophication in lakes. The multiquadric radial basis functions are used to solve numerically the governing partial differential equations. Because of the difficulty and the complexity when choosing a suitable shape parameter in radial basis functions, an alternative way is introduced in this work to overcome these difficulties. A validation study is carried out using several test examples, including Poisson, Navier–Stokes and transport equations. Finally, the proposed model is first applied to simulate a squared domain aeration problem and then a real test case has been considered. The obtained results are in good agreement with the results reported in the literature.