地下开采沉陷对滑坡灾害的影响分析

我国西部矿区大部分位于山区及丘岭地区,这种条件下开采往往会导致滑坡灾害的发生。利用FLAC3D模拟地下开采地表沉陷规律,分析开采沉陷对滑坡稳定性的影响。通过GeoStu-dio软件模拟降雨入渗下滑坡暂态渗流场,将计算得到的暂态孔隙水压力分布用于滑坡的极限平衡分析,并考虑基吸力对非饱和土抗剪强度的影响。探讨渗透系数、裂缝位置和深度对滑坡稳定性的影响。研究表明:降雨是诱发黄土层采动滑坡的主要因素,开采沉陷对采动滑坡稳定性的影响受控于采动区滑坡体结构形态、入渗能力、裂缝位置和深度。     

阴离子表面活性剂对微孔曝气氧传质过程影响的研究

阴离子表面活性剂在污水中广泛存在,并对曝气氧传质过程有重要影响.因此,通过试验研究了不同浓度的十二烷基苯磺酸钠(SDBS)对微孔曝气氧传质过程的影响.结果表明,当表面活性剂SDBS的浓度在0～5.74×10-5mol·L-1之间变化时,氧总转移系数(KLa)和水质修正系数(α)先减小后增大,在浓度为1.43×10-5 mol· L-1左右时最低.对于同一SDBS浓度,通气量越大,α值越大,说明大气量可以部分抵消表面活性剂对传质的不利影响.在低表面活性剂浓度(CsDBs＜ 1.43×10-5 mol· L-1)时,表面张力迅速下降,抑制传质作用占主导,此时KLα减小;随着表面活性剂浓度增大,由于气含率增大所带来的促进传质作用逐渐占主导,此时KLa增大.最终建立KLα和表面张力(γ∞)、气含率(b)之间的多元线性关系方程为:KLα =0.00024γ∞+0.094 b+0.044.     

新型三维多孔光热材料制备及其高盐废水处理应用

高盐废水处理存在处理难度大和能耗成本高等问题.近年来发展的界面光蒸汽水处理技术以绿色、高效和低能耗等特点成为了目前水资源回收利用领域的研究热点.本研究以纤维状结构的碳化氮（h-CN）修饰石墨烯（r-GO）,通过水热反应制备了新型三维多孔石墨烯复合材料（3D h-CN/r-GO）,并以硝基苯和苯酚作为模拟污染物,考察了其光热蒸发处理高盐废水的性能.研究结果表明,所制备的3D h-CN/r-GO材料具备宽光谱吸收范围和多级孔道结构,并呈现出快速热响应的特点.在模拟太阳光照条件下,光蒸汽转化效率可达90.4%.并且在处理过程中可实现硝基苯和苯酚等常见挥发性污染物的吸附,其吸附容量分别为67.6 mg·g^-1和57.5 mg·g^-1.而且,3D h-CN/r-GO可实现长时间稳定的光热水体蒸发回收,且对污染物及盐分截留率高达98%左右,冷凝水体达到污水处理的排放标准.因此,本研究为高盐废水的低能耗和低成本处理提供了一种新的技术.     

Urban environmental problems in cities of the Kurdistan region in Iraq

Cities in the Kurdistan region in Iraq – particularly, the capital city of Hewlair (Erbil) – are facing environmental problems such as water, air and noise pollution. Political instability, ethnic tensions, politically motivated decisions, wars and economic sanctions, consumerism, lack of sufficient funds, and tension between the federal and regional governments due to power and wealth sharing are major contributors to the environmental problems; this paper will depict and analyse these. Although these problems are causing serious health issues for the inhabitants and sometimes death, the authorities are unable to solve them. The paper sheds light on the causes and effects of the environmental problems and also draws conclusions and makes suggestions.     

Interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials: A review

The heterogeneous Fenton reaction can generate highly reactive hydroxyl radicals(·OH)from reactions between recyclable solid catalysts and H_2O_2 at acidic or even circumneutral pH.Hence,it can effectively oxidize refractory organics in water or soils and has become a promising environmentally friendly treatment technology.Due to the complex reaction system,the mechanism behind heterogeneous Fenton reactions remains unresolved but fascinating,and is crucial for understanding Fenton chemistry and the development and application of efficient heterogeneous Fenton technologies.Iron-based materials usually possess high catalytic activity,low cost,negligible toxicity and easy recovery,and are a superior type of heterogeneous Fenton catalysts.Therefore,this article reviews the fundamental but important interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials..OH,hydroperoxyl radicals/superoxide anions(HO_2./O_2~-.)and high-valent iron are the three main types of reactive oxygen species(ROS),with different oxidation reactivity and selectivity.Based on the mechanisms of ROS generation,the interfacial mechanisms of heterogeneous Fenton systems can be classified as the homogeneous Fenton mechanism induced by surface-leached iron,the heterogeneous catalysis mechanism,and the heterogeneous reaction-induced homogeneous mechanism.Different heterogeneous Fenton systems catalyzed by characteristic iron-based materials are comprehensively reviewed.Finally,related future research directions are also suggested.     

典型有机物与超滤膜界面作用及膜污染机制研究

对二级出水中典型有机物的膜通量及膜污染变化情况进行分析比较,并应用扩展DLVO(x DLVO)理论分析了有机物超滤过程中的界面作用能对膜污染行为的影响机制.研究表明,海藻酸钠(SA)导致的膜通量下降最为显著,其次为腐殖酸(HA)和牛血清白蛋白(BSA);就3种有机物而言,膜污染均主要发生在粘附阶段,而在粘聚阶段中膜污染程度较小.对比而言,海藻酸钠(SA)主要形成可逆污染,腐殖酸(HA)和牛血清白蛋白(BSA)则以不可逆污染为主.在过滤过程中,极性界面作用能是控制膜污染的主要因素,HA和BSA的极性界面作用能为正值,能抑制膜污染,而SA的极性界面作用能为负值,会加剧膜污染.3种有机物在粘聚阶段的极性界面作用能均大于粘附阶段,说明粘附阶段的膜污染更严重.     

生物型表面活性剂在煤表面润湿吸附规律研究

为了探讨生物型表面活性剂溶液在煤表面的润湿吸附规律,选定茶皂素、蔗糖酯、无患子和脂肽这4种结构性能不同的生物型表面活性剂作为研究对象,通过对4种溶液在煤表面接触角和表面张力进行测定,研究这4种生物型表面活性剂在煤表面的铺展系数、黏附功、黏附张力等润湿吸附参数。研究结果表明:脂肽的表面张力、接触角和黏附功均低于其他3种溶液,而其铺展系数高于其他3种溶液,说明脂肽在煤表面的润湿吸附性要强于茶皂素、蔗糖酯和无患子,但是黏附性则低于茶皂素、蔗糖酯和无患子。脂肽对煤体的润湿吸附性能优于另外3种生物型表面活性剂。     

有机污染物界面行为调控技术及其应用

污染物的多介质/多界面行为影响其赋存状态、迁移转化及生物生态效应.阐明污染物界面行为及其调控技术原理,是准确认识污染物源汇机制、预测其生物有效性、发展污染控制新材料与新技术的重要基础.本文介绍了典型有机污染物的多介质界面行为及其微观机制,表面活性剂调控有机污染物固-液界面分配行为及生物有效性的基本原理,重点阐述了污染物界面行为调控技术在难降解有机废水吸附处理、土壤有机污染缓解与修复中的应用.     

Influence of additives in the end‐use mixes of tebufenozide on deposition,adhesion and persistence in spruce foliage

Abstract

A commercial flowable formulation of tebufenozide, RH‐5992 2F [N'‐t‐butyl‐N'‐(3,5‐dimethylbenzoyl)‐N‐(4‐ethylbenzoyl) hydrazine], was diluted with water, water and canola oil, and water and the methyl ester of canola oil, to provide six end‐use mixes with concentrations of 35 and 70 g of active ingredient (Al) litre^‐1. The mixes were applied at 70 and 140 g Al ha^‐1 over white spruce [Picea glauca (Moench) Voss] seedlings in a laboratory spray chamber and foliar concentrations of tebufenozide were determined over a 60‐d period. At intervals of time post‐spray, seedlings were sprayed with monosized droplets of Sunspray®11N as rainfall, and the amount of tebufenozide knocked off from foliage was determined. The potential energy of adhesion (PEA) of the Al particles on the foliage increased with time and varied according to the type of end‐use mix, its viscosity and the dosage sprayed.

The end‐use mixes were applied over white spruce trees under field conditions and persistence of tebufenozide was investigated. DT₅₀ values were influenced by the type of mix and dosage sprayed. Oil‐containing mixes and higher dosages increased the PEA of tebufenozide particles.     

Hopkinson压杆反射拉伸下PMMA动态破坏现象实验研究

利用Hopkinson压杆系统对PMMA变截面柱锥试样进行冲击加载，研究材料动态拉伸断裂特性和破坏机理。由于PMMA的拉压强度差别不大，采用圆柱状试件难以产生反射拉伸破坏，因此，将试样设计为圆柱锥状，实验时，将试样的圆柱端粘贴于输入杆上。实验结果表明，在一定的撞击速度下，由于应力波的汇聚作用，在试样锥段产生了反射拉伸破坏；当撞击速度较高时，在产生反射拉伸破坏的同时，试件中还产生了银纹区，随着打击速度的提高，银纹区域增大。同时根据断口的SEM观察，研究了材料的破坏机制。