GIS技术在城市地下水重金属浓度识别与分级中的应用（英文）

Groundwater is the most appropriate and widely used source of drinking water,which is increasingly threatened by pollution from industrial and agricultural activities.To check the severity of the problem,156 groundwater samples were collected from various depths(60-110 ft) of 52 different localities in Faisalabad city,the third largest metropolis in Pakistan,and analyzed for the metals(Zn,Cu,Cd,Ni,Pb,Mn and Fe) concentration in 2009.Quantification was done by using Flame Atomic Absorption Spectrophotometer technique and the results were compared with WHO standards for drinking water quality.Results showed that the levels of Cu,Mn and Fe were below the WHO standards while the concentrations of Zn,Cd,Ni and Pb were above the recommended levels of safe drinking water.Correlation analysis among the occurrence of these heavy metals revealed a highly significant and positive correlation of Mn with Zn and Fe.A significant and positive correlation of Cd was also found with Cu and groundwater depth showing that there is strong association between Cu-Cd pair and that the Cd concentration varies with depth of groundwater in the study area.Regional patterns of heavy metals occurrence were mapped using Geographical Information System(GIS) for the identification and demarcation of risk areas.The concentration maps may be used by policymakers of the city to mitigate groundwater pollution.     

Relationship between Agricultural Land Use and Spatial Heterogeneity in Quality of Water Resources in Haean Basin of Korea

Water Resources - In the Republic of Korea, Haean basin is the largest agricultural area in Soyang watershed which is drinking water source for more than 20 million people residing in Seoul...     

Hypsometric properties of mountain landscape of Hunza River Basin of the Karakoram Himalaya

Within Karakoram Himalaya, Hunza River Basin(study area) is unique for a number of reasons: 1) potential impacts of highly concentrated highpitched mountains and glacial ice; 2) the glaciated portions have higher mean altitude as compared to other glaciated landscapes in the Karakoram; 3) this basin occupies varieties of both clean and debriscovered glaciers and/or ice. Therefore, it is imperative to understand the stability of topographic surface and potential implications of fluctuating glacial-ice causing variations in the movement of material from higher to lower elevations. This paper advocates landscape-level hypsometric investigations of glaciated landscape lies between 2280–7850 m elevation above sea level and non-glaciated landscape between 1461–7570 m. An attempt is made to understand intermediate elevations, which disguise the characteristics of glaciated hypsometries that are highly correlated with the Equilibrium Line Altitude(ELA). However, due to data scarcity for high altitude regions especially above 5000 m elevation, literature values for climatic conditions are used to create a relationship between hypsometry and variations in climate and ELA. The largest glaciated area(29.22%) between 5047 to 5555 m lies in the vertical regime of direct snow-accumulation zone and in the horizontal regime of net-accumulation zone(low velocity, net freezing, and no-sliding). In both landscapes, the hypsometric curves are ‘slow beginning' followed by ‘steep progress' and finally reaching a ‘plateau', reflecting the rapid altitudinal changes and the dominance of fluvial transport resulting in the denudation of land-dwelling and the transport of rock/debris from higher to lower altitudes. Reported slight differences in the average normalized bin altitudes against the cumulative normalized area between glaciated and non-glaciated landscapes are an indicator of slightly different land-forms and landform changes.     

Spatial modeling of Dengue prevalence and kriging prediction of Dengue outbreak in Khyber Pakhtunkhwa (Pakistan) using presence only data

Stochastic Environmental Research and Risk Assessment - During the span of August–October, 2017 a major outbreak of Dengue fever happened in Khyber Pakhtunkhwa province of Pakistan. Cases...     

Synthesis,Mechanism, and Performance Assessment of Zero‐Valent Iron for Metal‐Contaminated Water Remediation: A Review

Recently, increased industrial and agriculture activities have resulted in toxic metal ions, which has increased public concern about the quality of surface and groundwater. Various types of physical, biological, and chemical approaches have been developed to remove surface and groundwater metal ions contaminants. Among these practices, zero‐valent iron (ZVI) is the most studied reactive material for environmental clean‐up over the last two decade and so. Although ZVI can remove the contaminants even more efficiently than any other reactive materials. However, low reactivity due to its intrinsic passive layer, narrow working pH, and the loss of hydraulic conductivity due to the precipitation of metal hydroxides and metal carbonates limits its wide‐scale application. The aim of this work is to document properties, synthesis, and reaction mechanism of ZVI for the treatment of metal ions from the surface and groundwater in recent 10 years (2008–2018). So far, different modified techniques such as conjugation with support, bimetal alloying, weak magnetic field, and ZVI/oxidant coupling system have been developed to facilitate the use of ZVI in various environmental remediation scenarios. However, some challenges still remain to be addressed. Therefore, development and research in this field are needed to overcome or mitigate these limitations.     

无人机组网遥感实时任务观测的冗余容错控制方案

中小型无人机（UAV）越来越多地应用于各种实时静态和动态任务中,已成为对人类非常有用的辅助工具。适合无人机在各种条件下进行监视和测量的因素有很多,但无人机在执行不同的实时任务时仍会受到各种挑战,且一旦在任务执行过程中任何一个约束的及时响应缺失,将会影响任务的总体结果,导致整个任务部分或完全失败,在实际中很难建立完美系统。因此,在系统中引入冗余容错来最小化故障概率并增强其鲁棒性非常重要。其中,根本问题是随着系统复杂性的增加,除非对其采取补偿措施,否则其可靠性会急剧下降。冗余容错是通过添加一个或多个模块（通常采用并行配置）作为备份来引入冗余。为了提高极端条件下航空遥感任务无人机网络系统的鲁棒性和成功率,本文将基于冗余的容错控制技术引入无人机网络设计中,确定了不同限制条件下的最佳网络解决方案。组网设计是在不同观测条件下的遥感任务如“大尺度生态监测”、“中尺度洪灾监测”、“小尺度安全监测” 中,通过同步监控进行主动合作的包括多个无人机的网络。多无人机网络作为冗余容错体系结构时可以通过添加多个无人机作为备份使得系统可以容错,而无人机在不同极端条件下的位置和视角则可以作为冗余容错的场景设置。当组网方案中的无人机位置和视角超过设定的阈值时可以被认为是故障的,其将被分离并不考虑进一步分析。通过以上方式,无人机网络可以在极端条件下得到组网控制方案的有效输出,进而保证遥感观测任务的顺利进行。     

Influence of drainage and root biomass on soil mechanical behavior in triaxial tests

Acta Geotechnica - This paper presents a study in which triaxial tests were performed on loess soil reinforced with natural roots. Triaxial compression tests were performed on soil specimens with...     

Geoelectrical resistivity survey for the evaluation of hydrogeological condition of Bagerhat Sadar and the adjacent areas, Bangladesh

This study has been conducted to find out the aquifer characteristics of Bagerhat Sadar and adjacent areas in Bangladesh using geoelectrical resistivity method and borehole logs. The interpretation of resistivity soundings (14 nos.) shows that the sub-surface lithological sequence can be divided into four geoelectric units. The deepest geoelectric unit (with resistivity from 8 Ohm-m to 18 Ohm-m) represents the deep aquifer with usually fresh water. Resistivity values of 12 ?m or more for this unit may indicate formation water as acceptable for coastal people. In the study area, the shallow aquifer inferred is not suitable for groundwater development.     

Evaluation of coal as adsorbent for phosphate removal

This paper reports the adsorption of phosphate ions on coal, charcoal, and coal ash. The influences of factors such as contact time, and initial adsorbate concentration have been studied. Adsorption of phosphate ions on virgin coal was significant compared to charcoal, coal and coal ash evacuated at 200°C. The significant adsorption capability of coal is due to the porosity as well as due to organic carbon and inorganic elements present in coal. The evacuation of coal proved to be ineffective in enhancing its capability for phosphate ions retention. The adsorption behaviors of all the three adsorbent used was conformed using Freundlich’s adsorption model. The results suggest that coal could be used as an efficient adsorbent for removing phosphate ions from wastewater.