Solid Phase Extraction of Trace Elements in Water and Tissue Samples on a Mini Column with Diphenylcarbazone Impregnated Nano‐TiO2 and Their Determination by Inductively Coupled Plasma Optical Emission Spectrometry          下载免费PDF全文

Sıtkı Baytak  Zikri Arslan 《洁净——土壤、空气、水》2015,43(6):822-829

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Chelant‐assisted Phytostabilization of Paint‐contaminated Residential Sites     

Syam S. Andra  Dibyendu Sarkar  Sumathi K. M. Saminathan  Rupali Datta 《洁净——土壤、空气、水》2010,38(9):803-811

Following the basic incubation study, a greenhouse experiment was conducted to elucidate the efficiency of vetiver grass (Vetiveria zizanioides L.), with or without chelating agents, in remediating lead (Pb)‐contaminated soils from actual residential sites where Pb‐based paints were used. Because the primary factor affecting Pb phytoavailability in soils is soil pH, we used two soil types widely varying in pH that have total Pb concentrations above 1500 mg kg^?1 soil. Lead‐contaminated, low pH, acidic soils were collected from residential sites in Baltimore, MD and high pH, alkaline soils were collected from residential sites in San Antonio, TX. Based on the soil characterization results, two most appropriate soils (one from each city, having similar Pb levels but variable soil physico‐chemical properties) were selected for this study. Ethylenediaminetetraacetic acid (EDTA) and [S,S′]ethylenediaminedisuccinate (EDDS) were applied at 5, 10, and 15 mmol kg^?1 soil. Lead uptake and translocation in vetiver was determined on day 10 after chelants addition. Plant and soil analysis show that EDTA treated soils have maximum Pb uptake and lower total soil Pb levels. Prediction models developed for exchangeable Pb show a strong correlation for total Pb accumulated in vetiver grass. Results of the sequential chemical extraction of the soils at both initial and final time‐points, indicates a significant mobilization of Pb by the two chelants from carbonate‐bound fraction to exchangeable pool. Information on physico‐chemical properties of contaminated residential soils help in predicting Pb phytoextraction and thus further help in calibrating a successful chelant‐assisted phytoremediation model.  相似文献   

新型复合胶无粘土冲洗液研究及应用     

吴飞  陈礼仪  朱宗培  费立  吴丽 《煤田地质与勘探》2003,31(5):57-59

针对松散覆盖层、强风化破碎层取心率低,岩心松散破碎,孔壁稳定性差等问题,进行了以天然植物胶为主原料的处理剂复配改性研究和冲洗液优化配方研究。主要研究方法是通过有机聚合物和无机交联剂的作用,对羟丙基瓜尔胶(GRJ)进行交联改性,以此获得新型复合胶无粘土冲洗液优化配方,并进行了现场应用。应用效果表明,该冲洗液密度低,粘度可调范围大,流变性和润滑性好,成膜护心、护壁作用强,完全满足第四系覆盖层、胶结差的砂卵石层和强风化破碎地层取心钻进要求。   相似文献   

Modelling the spatial evolution of map objects by map agents     

Shen Ying  Wan Wen  Yuan Wan  Xinqiao Duan 《国际地球制图》2016,31(4):408-427

To overcome the weakness of modelling the relationships between map objects that represent the same geographic entities or phenomena at different times and scales, an agent-based approach is presented to modelling of the spatial evolution of map objects for better understanding of the evolutional process of different maps. Map agents are used to establish and manage the many-to-many corresponding relationships between map objects, and they render map objects active rather than traditionally passive. The evolutions of map objects are modelled by map agents using association and generation relationships to model the connectivity between map objects. This effort reduces the workload of multi-scale map updating by avoiding update of the entire map; instead, it simply allows map agents to detect, perceive and choose suitable behaviours on which to operate and update a spatially evolving object. Experiments of specific examples are presented to demonstrate the feasibility and the effectiveness of our approach.  相似文献   

微晶白云母活性填料的铝酸酯表面改性研究   总被引：5，自引：0，他引：5  

叶巧明  汪灵  刘菁  林金辉  邓苗 《矿物岩石》2005,25(3):83-87

以微晶白云母为研究对象,铝酸酯DL-411-D为改性剂,研究探讨微晶白云母铝酸酯表面改性工艺务件及其表征方法。经粘度和红外光谱研究证实粘度测试法是确定铝酸酯改性微晶白云母偶联剂用量的有效方法;铝酸酯偶联剂改性微晶白云母工艺简单,偶联剂用量低,不需使用稀释剂,成本低,效果好;改性后的微晶白云母在有机介质中的分散性得到显著提高,因而可大幅度提高其在高聚物中的填充量,降低复合材料的成本。实验结果还表明,铝酸酯改性微晶白云母后,没有发现化学结合的新证据,而更多地显示出物理包覆的特征。  相似文献   

Geospatial Agents, Agents Everywhere . . .   总被引：1，自引：0，他引：1  

Raja Sengupta  Renée Sieber 《Transactions in GIS》2007,11(4):483-506

The use of the related terms “agent‐based”, “multi‐agent”, “software agent” and “intelligent agent” have witnessed significant growth in the Geographic Information Science (GIScience) literature in the past decade. These terms usually refer to both artificial life agents that simulate human and animal behavior and software agents that support human‐computer interactions. In this article we first comprehensively review both types of agents. Then we argue that both these categories of agents borrow from Artificial Intelligence (AI) research, requiring them to share the characteristics of and be similar to AI agents. We also argue that geospatial agents form a distinct category of AI agents because they are explicit about geography and geographic data models. Our overall goal is to first capture the diversity of, and then define and categorize GIScience agent research into geospatial agents, thereby capturing the diversity of agent‐oriented architectures and applications that have been developed in the recent past to present a holistic review of geospatial agents.  相似文献   

    

Yu Xing  Dai Jin  Jiang Weimei  Fan Peng 《大气科学进展》2000,17(4):617-635

It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three–dimensional puff trajectory model incorporating a mesoscale nonhydrostatic model has been formulated, and is applied to simulating the transporting and diffusive characteristics of multiple line sources of seeding agents within super–cooled stratus. Several important factors are taken into consideration that affect the diffusion of seeding materials such as effects of topography and vertical wind shear, temporal and spatial variation of seeding parameters and wet deposition. The particles of seeding agents are assumed to be almost inert, they have no interaction with the particles of the cloud or precipitation except that they are washed out by precipitation. The model validity is demonstrated by the analyses and comparisons of model results, and checked by the sensitivity experiments of diffusive coefficients and atmospheric stratification. The advantage of this model includes not only its exact reflection of heterogeneity and unsteadiness of background fields, but also its good simulation of transport and diffusion of multiple line sources. The horizontal diffusion rate and the horizontal transport distance have been proposed that they usually were difficult to obtain in other models. In this simulation the horizontal diffusion rate is 0.82 m s⁻¹ for average of one hour, and the horizontal average transport distance reaches 65 km after 1 h, which are closely related to the background fields.  相似文献   

The second law of geography for a spatially enabled economy     

《International Journal of Digital Earth》2013,6(10):979-995

ABSTRACT

Location has proven axiomatic as an economic variable throughout human history. Tobler’s first law of geography introduced the importance of location; in that, near things are more related than far things. In an age of digital economies, a new research frontier exists where everything is more related to everything else and has an increased economic value from spatially enabled technology. The accessibility of digital-spatial information has brought economic geographers to a new understanding of markets within a Digital Earth framework. The importance of location to economic value can be expected to grow as the Internet of Things develops in sophistication. New business models enter and disrupt established markets with innovative spatially enabled approaches. A successful penetration of established markets suggests a new business model for financial and functional utility by engaging spatially enabled assets. The second law of geography is introduced as a conceptual framework to comprehend the economic potential of spatially enabled information. A comparative analysis of non-spatial versus spatial web agents provides a quantitative framework to demonstrate the benefits of the Digital Earth economy.  相似文献   

Exploring Obstacles toEducational Reform: Observations from Finding a Way     

《The Professional geographer》2013,65(4):578-585

This paper examines teachers' expressions of concerns and resistance to the idea of making their classrooms gender equitable. The observations made here arose in the context of the National Science Foundation-funded National Council for Geographic Education Finding A Way project. During Finding A Way summer institutes, teachers were asked to look critically at themselves and reflect on their classroom practices. From their journal entries and personal narratives, it was found that teachers frequently experience powerful emotional responses and cognitive dissonance when asked to address issues of equity in their classrooms. Dissonance, ambivalence, and resistance surfaced most often over the “request” that they become proactive. We found that Finding A Way was most successful with those teachers who were willing to assume the role of “change agents” and who were personally invested in the outcome. Heretofore, professional development research in geography has been remarkably silent on the issue of teacher resistance to educational reform initiatives.  相似文献   

Development and testing of a new protocol for evaluating the effectiveness of oil spill surface washing agents   总被引：1，自引：0，他引：1  

Karen Miller Koran  Albert D. Venosa  Christopher C. Luedeker  Keith Dunnigan  George A. Sorial 《Marine pollution bulletin》2009,58(12):1903-1908

As defined by the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), a surface washing agent (SWA) is a product that removes oil from solid surfaces, such as beaches, rocks, and concrete, through a detergency mechanism and that does not involve dispersing or solubilizing the oil into the water column. Commercial products require testing to qualify for listing on the NCP Product Schedule. Such testing is conducted both for toxicity and effectiveness. Protocols currently exist for bioremediation agents and dispersants, but not SWAs. The US Environmental Protection Agency (EPA) is developing a laboratory testing protocol to evaluate the effectiveness of SWAs in removing crude oil from a solid substrate. This paper summarizes some of the defining research supporting this new protocol. Multiple variables were tested to determine their effect on SWA performance. The protocol was most sensitive to SWA-to-oil ratio and rotational speed of mixing. Less sensitive variables were contact time, mixing time, and SWA concentration when total applied mass of active product was constant. EPA recommendations for the testing protocol will be made following round robin testing.  相似文献