A fractal derivative model to quantify bed-load transport along a heterogeneous sand bed

Environmental Fluid Mechanics - Bed-load transport is a complex process exhibiting anomalous dynamics, which cannot be efficiently described using the traditional advection–diffusion...     

落地油泥土壤性质对超声除油效果的影响

落地油泥是油田产生的一类危险固体废弃物,其无害化处理是目前各大油田所面临的重大挑战之一。为了深入认识超声处理过程中油泥土壤性质与超声处理除油效果之间的关系,以不同油田典型落地油泥为研究对象,超声处理后对其土壤残留含油量、土壤颗粒级配、土壤化学组成等进行分析。结果表明:油泥中土壤颗粒粒径较大的大庆、大港落地油泥经超声处理后的除油效果均在60%以上,而土壤颗粒粒径较小的冀东落地油泥超声除油率仅为11%;同时,超声除油效果较好的大庆、大港落地油泥中的钙氧化物含量较低(分别为4.84%和5.94%),而超声除油效果差的冀东落地油泥中的钙氧化物含量较高(11.57%)。进一步的模拟实验结果表明,钙氧化物含量高的土壤对原油的吸附量大、吸附强度高、超声除油效果差,而钙氧化物含量低的土壤吸附量小、吸附强度低、超声除油效果好。以上结果可为油田落地油泥超声处理技术的开发及规模化应用提供指导。     

某基岩区工业固体废物填埋场地递进式场地环境调查实例

针对某基岩区简易封场后的固体废物填埋场,采用多层次、递进式调查策略,配合使用地球物理探测、直压式土壤快速取样、现场快速检测等技术,分3个阶段开展填埋场及其周边环境调查。第1阶段,调查地质环境特征,开展地球物理探测;第2阶段,调查填埋物、渗滤液主要组分及对周边积水、农田土壤、民用井水的污染情况;第3阶段,划定重点污染区域,开展土壤和地下水污染调查。调查结果显示,填埋区已发生明显渗漏,对邻近区域土壤、地下水及地表积水造成了一定污染,但未对周边农用地土壤、民用井水质等产生不利影响,总体处于可控范围。提出,通过削减污染源,切断污染物迁移、暴露途径,消除已有污染影响,长期跟踪监测等多项管控治理措施进行综合整治。     

磁浮列车电磁辐射仿真与验证评估技术研究

磁浮列车正常行进过程中对外部环境的电磁辐射安全性近年来受到各科技强国的广泛重视。本文采用多线传输线MTL方法,对磁浮列车电磁辐射场进行了电磁建模与仿真分析,并基于IEEE-Std-C95.1-2005、IEEEStd-C95.6-2002和ICNIP-2010以及GB8702-2014,标准,采用传感器法和接收天线法,现场测试验证了磁浮列车在不同运行状态下的电磁辐射场,开展电磁环境评估工作。研究表明:50～110 kHz,磁浮列车12 m处的辐射磁场呈周期性结构分布,仿真的最大值为69.4 dBuA/m;1～120 kHz频段内,磁浮列车的辐射磁场测量值小于90 mA/m;在9 kHz～18 GHz频段内,磁浮列车的辐射电场均小于110 dBuV/m(0.316 V/m),磁浮列车对外电磁辐射量值比相关国际标准限值至少低30 dB。本论文的研究工作可为我国新型高速磁浮列车电磁安全性研究奠定基础。     

How does “the Belt and Road” and the Sino-US trade conflict affect global and Chinese CO2 emissions?

Environmental Science and Pollution Research - In the context of the rapid development of the Belt and Road (B&R) Initiative, the continuous transfer of Sino-US trade to the B&R...     

Effects of reciprocal hybridization on cadmium accumulation in F1 hybrids of two Solanum photeinocarpum ecotypes

In this study, farmland and mining ecotypes of Solanum photeinocarpum (a potential cadmium (Cd) hyperaccumulator plant) were reciprocally hybridized each other, and the Cd accumulation characteristics of the F1 hybrids were studied. In pot experiments, higher biomasses and Cd extraction abilities were found for two S. photeinocarpum F1 hybrids than for the parents, but the Cd contents in various organs were lower in the hybrids than the parents. However, the differences between the Cd contents in the two hybrids were not significant. The antioxidant enzyme (superoxide dismutase and peroxidase) activities were higher for the S. photeinocarpum F1 hybrids than the parents. Less DNA methylation was found in the hybrids than the parents because more demethylation occurred in the hybrids than the parents. The biomass, Cd content, and Cd extraction ability effects in field experiments were similar to the effects in the pot experiments. It was concluded that reciprocally hybridizing different S. photeinocarpum ecotypes improved the ability of S. photeinocarpum to be used to phytoremediate contaminated land.

     

Little Egrets (Egretta Garzetta) and Trace-Metal Contamination in Wetlands of China

The rapidly developing Asian countries may face threatening environmental contamination, that however remains largely unassessed. We studied persistent trace elements in three wetlands, Poyang Lake, relatively unpolluted, and Tai Lake, and Pearl River Delta, selected as hotspots of pollution in Central China. We adopted as indicator the Little Egret, a widespread colonial waterbird, and during 1999 and 2000 we collected and analysed the same samples as for a parallel study we conducted in Pakistan, e.g. eggs, body feathers of chicks, prey spontaneously regurgitated by the chicks, and sediments at the areas most used by foraging egrets. The levels of trace-metals at our three study areas were similar, or within the range, of those found in the few other studies for East Asia, with few exceptions. The concentrations of the various elements were below the threshold that may affect the survival or reproduction of the birds, and even the highest concentrations relative to background, i.e. Se in eggs, and Hg in feathers at Pearl Delta, do not pose toxic hazards. In sediments, the levels of trace elements were lower than the critical levels assumed for contaminated soil, except for alarming high levels of As at Poyang. These results do not confirm our expectation, that Poyang was relatively uncontaminated, while Tai and Pearl were polluted. Although trace metal concentration differed significantly among the three study areas, these differences were minor and were not consistent among elements and samples. The bioaccumulation ratios from sediments through prey, feather and egg, were consistent with our previous findings for Pakistan. Only Hg exhibited high bioaccumulation, while Se and Zn had low accumulation, and the other elements no accumulation. This reasserts that feathers of predators such as egrets, may be more sensitive indicators of environmental contamination for the elements subject to bioaccumulation, whereas the sediments or the organisms low in the food chain are better indicators for the other elements.     

基于可拓物元模型的安全经济开采评价指标体系的构建及应用

首先根据安全经济开采的内涵,建立以人员安全、设施设备安全、开采环境安全、安全投资和安全管理为主要制约因素的安全经济开采评价模型,并运用改进的层次分析法确定人员可靠度对安全经济开采水平影响最大,开采环境可靠度影响最小。其次,采用函数拟合法、专家打分法、标准化打分法量化安全经济开采水平指标,并将安全经济开采水平划分为3个等级。最后,运用可拓物元模型方法,得出某铁矿安全经济开采水平为二级,无重大经济损失,与实际吻合。     

扎哈淖尔露天煤矿南帮压煤回采边坡稳定性分析

针对露天矿边帮普遍存在的压煤问题,基于极限平衡及强度折减理论,从控制边坡稳定性角度出发,结合扎哈淖尔露天煤矿南帮软岩边坡工程实际,通过定量计算与定性分析,提出横采内排压帮开采方式。采用二维刚体极限平衡与三维数值模拟相结合的方法分析了横采深部开挖角度及内排跟踪距离对边坡稳定性的影响及其程度,优化设计了扎哈哈淖尔露天矿横采南帮边坡形态。结果表明:南帮边坡滑坡模式为以IVC煤层底板弱层为底界面的切层-顺层滑动;横采内排压帮开采方式可借助边坡三维效应提高露天矿边坡角度及其自身稳定性,进而达到安全、高效地回收边帮压煤,提高露天矿煤炭资源回收率;扎哈淖尔露天煤矿横采南帮边坡稳定性随内排跟踪距离增大呈负指数降低;最终确定横采开挖位置为+908水平,内排跟踪距离为100 m,深部开挖角度为42°,可累计为扎哈淖尔露天煤矿多采出IV煤4 701.39万t,经济效益显著。