Re-examination of Eulerian-Lagrangian turbulence relationships

Eulerian-Lagrangian relationships calculated from Monte Carlo simulation of particle movements are compared with estimates from analytical approximations based on Lagrangian kinematic relationships. Results of a one-dimensional numerical simulation and a three-dimensional analytical approximation for isotropic homogeneous turbulence are discussed. The Monte Carlo simulation is mathematically and physically similar to the analytical approximation despite the fact that the numerical simulation is fundamentally incorrect for three-dimensional turbulence.     

生物法处理含油钻井废水的影响因素研究

以含油钻井废水原浆为处理对象,研究了生物法处理过程中的相关影响因素.实验结果表明,氮、磷源是影响钻井废水中石油烃降解的重要因素,最佳氮、磷源及其加入量分别为(NH4)2SO4100 mg/L和KH2PO460 mg/L.在30～36℃,接种量15%,pH=6～8条件下处理72 h后可使钻井废水中的石油烃含量由805.6 mg/L下降到17.6 mg/L.     

论中国环境预警制度的法治化--以行政权力的规制为核心

环境预警制度蕴含了一项使行政权力合法扩张的"对应性架构",即预警级别与"强制型"或"限制型"措施之间的充分必要关系。在制度运行过程当中,环境行政权力却出现了"选择性失语"和"运动式肆意"的问题,具体表现为:一是预警级别发布时的"隐匿"与"从轻",从而对公民健康权益保护不足;二是预警状态下环境行政权力的扩张过度,使得对个人自由与企业经济自由侵害过度。由于环境治理领域"被害人-加害人"二元对立关系的模糊化、趋同化甚至同一化,传统公法学体系中的权力制约理论无法对预警状态下多样化和多层次性的行政权力进行有效地规制。那么,便有必要对现有的环境预警制度进行修正与纠偏。因此,可以从"对应性架构"的载体及其前后两端入手,对环境预警制度进行法治化建构。具体而言,对环境预警的载体"应急预案"进行形式改造,提高环境应急预案的规范层级,完善环境应急预案制定、修改等程序性规定;明确不同预警级别设定的规范层级,将作为被宪法所保护的客观利益——生态环境利益与经济利益的边界——通过"前端"预警标准予以划分;对预警状态下行政权力的"外部"制约程序予以完善。基于预警级别标准体系的划分,可以通过司法程序对"后端"环境应急预案进行"附带性审查",同时,赋予私主体直接针对预警状态下具有"外化"法效力的内部行政行为提起行政诉讼的诉权。     

单块集尘板振打加速度的有限元分析

采用有限元分析软件ABAQUS,对单块集尘板振打加速度进行了分析计算。并将计算结果与解析法和实测法结果进行对比。对比结果表明,有限元计算值更接近于实测值。用有限元法对某厂实际运行的电除尘器加速度进行求解,计算结果与实际基本吻合。由于有限元法能非常方便地处理各种复杂板型、不同的悬挂方式、振打锤的大小以及振打方式,因此,有限元法对于现有极板的分析与新型极板的研究均具有重要的实际意义。     

Comparison of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in airborne particulates collected in downtown and suburban Kanazawa,Japan

In this study, airborne particulates were collected at three sites, two in a downtown area and the other in a suburban area of Kanazawa, Japan in each season for 7 years. Two polycyclic aromatic hydrocarbons (PAHs), pyrene (Py) and benzo[a]pyrene (BaP) and four nitropolycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (NP) and 1,3-, 1,6-, and 1,8-dinitropyrenes (DNP) were determined by high-performance liquid chromatography with fluorescence and chemiluminescence detection. At the downtown sites, the mean concentration of each DNP was about two orders of magnitude lower than that of 1-NP and more than three orders of magnitude lower than those of Py and BaP. This tendency reflected the composition of PAHs and NPAHs in diesel-engine exhaust particulates. Concentrations of these PAHs and NPAHs were higher at the downtown sites than at the suburban site, suggesting the dilution of these compounds during the transportation from the downtown to the suburban area. The concentration ratios of NPAHs to PAHs were larger at the downtown sites than at the suburban site. Studies using UV light and sunlight showed that degradation of NPAHs was faster than that of PAHs. Thus, the lower concentrations of NPAHs in the suburban sites may be due to their being photodegraded faster than PAHs during the atmospheric transportation from the downtown area to the suburban area.     

碱激发电解锰渣制备水泥掺合料

电解锰渣是湿法冶炼金属锰的残渣,为降低其对环境的浸出毒性影响并提高其在水泥产品中的掺入量,利用碱激发技术处理电解锰渣制备水泥掺合料是一种可行的方法。主要研究了碱激发剂种类、掺量对电解锰渣的激发效果,并将碱激发电解锰渣用作水泥掺合料与水泥按不同比例混合研究对水泥抗压强度和浸出毒性的影响。结果表明：碱激发电解锰渣活性显著提高,NaOH中Na2O当量为10%时试件M-SH10的3、7、28 d抗压强度最高,分别为7.15、9.46、10.03 MPa;将此条件下激发的电解锰渣按质量比取15%与85%的水泥混合制得的掺合料其抗压强度较净水泥试件有一定程度的提高;浸出毒性结果显示Cd、Cr、Pb、Ni、Mn和Zn浓度均下降,且低于GB 8978-1996限值。     

Anammox-HAP颗粒污泥型膨胀床反应器的氮磷同步去除能力及污泥特性

为实现集成、高效的氮磷处理,提高厌氧氨氧化工艺的运行稳定性及功能集成性,搭建了一种新型的anammox-HAP颗粒污泥型膨胀床反应器。设置了3个不同温度条件下的反应器,通过控制进入反应器中的钙、磷元素,以及调控反应器pH,探究了膨胀床反应器对氮、磷的同步去除能力,并对污泥特性进行了分析。结果表明：anammox-HAP颗粒污泥型膨胀床反应器在35、25、15℃条件下均可稳定运行,并能分别实现(44.90±0.32)、(17.12±0.97)、(8.79±0.14 ) g·(L·d)⁻¹的氮去除速率,且总氮去除率稳定维持在85%以上;磷元素以HAP核的形式聚集在anammox颗粒内部,可在随剩余污泥排出的同时进行回收;anammox-HAP反应器中颗粒污泥的沉降性能明显高于一般厌氧或anammox工艺中的颗粒污泥,并与颗粒中的磷含量正相关。本研究阐释了anammox-HAP颗粒污泥型膨胀床反应器的特点,可为废水中氮磷的处理提供参考。     

Experimental study on static and dynamic mechanical properties of phosphogypsum

Environmental Science and Pollution Research - Phosphogypsum (PG) is a solid waste product of the wet-process phosphoric acid industry that accumulates in large amounts on the ground, forming PG...     

表面活性剂CMC对石油烃污染土壤的增溶

研究了表面活性剂羧甲基纤维素钠（carboxyl methyl cellulose,CMC）对土壤中石油污染物的增溶作用。通过批实验,对比研究了CMC和十二烷基苯磺酸钠SDBS 2种表面活性剂的增溶效果,探究了CMC浓度、pH、盐度及回用次数对土壤中石油烃增溶效果的影响。研究结果表明,当CMC浓度为0.5%,增溶时间为24 h时,对TPHs浓度为17 695 mg·kg-1的污染土样,TPHs洗脱率高达60%以上。碱性环境有利于石油烃的洗脱,酸性体系会抑制石油烃的洗脱;增溶作用随盐度的增大而显著增大。在利用CMC对污染土壤进行增溶洗脱时,对于TPHs高浓度污染土壤,可以选择将其洗脱液回用1次或者2次;对于TPHs较低浓度污染土壤,可以选择将其洗脱液回用于较高浓度的污染土壤。     

Thermodynamic investigation and hydrate inhibition of real gas flow through orifice during depressurization

A thermodynamic procedure has been proposed which can be used to predict the gas pressure, temperature and flow rate through orifice upon chock flow condition, using equation of state (EOS). The procedure applied for emergency depressurization operation incorporating the Peng-Robinson EOS and validated by comparing flow rates of a multi-component hydrocarbon gas mixture for thirteen experimental cases. The average absolute deviations of the predicted flow rates for orifice discharge coefficients of 0.85 and 0.9, are 7.36% and 2.03%, respectively. The corresponding error for API 520 (American Petroleum Institute Recommendation Practice 520) method is 6.91%. In this work, the hydrate formation temperature and hydrate inhibitor type and its required weight fraction for preventing the hydrate formation upon orifice and its upstream conditions are evaluated by the EZ-Thermo software using the Moshfeghian–Maddox method. The results qualitatively show that the hydrate prevention is essential for the safety of the operation due to low temperature condition.