توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقالههای نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده میشوند.
اطلاعات انتشار: اولین کنفرانس بین المللی بحران آب، سال ۱۳۸۷
تعداد صفحات: ۹
An integrated novel, two–dimensional, numerical groundwater–surface flow model has been developed to simulate hydro–environmental interactions between wetland areas, the neighbouring coastal waters and the groundwater passages. For free surface flow modelling, an existing widely used two–dimensional, unsteady mathematical model, DIVAST (developed originally by Falconer 1976) has been refined. However, in order to simulate the flow and solute transport in porous media, a two–dimensional model, GWK (Ground Water Key), has been developed to include an aquifer influenced by tidal currents. The GWK model is based on the transient flow Boussinesq equation as the governing equation for groundwater flow, and the advection–diffusion equation is used as the governing equation for contaminant transport. A physical model has been constructed to provide experimental data of the groundwater transport between a wetland and the adjacent coastal waters. In the physical model the aim has been to study seepage behavior through the sand embankment by recording water levels on both sides of the sand, point velocity measurements, and the studies of a conservative dye tracer (a solute of 5g\l concentrations potassium permanganate) for constant water levels on one side of the embankment while running tidal cycle on the other side of the embankment. Comparison between the experimental data and the simulated physical model, involving integrated model, showed that the integrated model was capable of simulating groundwater and free surface water, with a high level of accuracy. An overview of the study is reported in this paper.<\div>
اطلاعات انتشار: International Journal Of Environmental Research، پنجم،شماره۱، Winter ۲۰۱۱، سال ۰
تعداد صفحات: ۱۰
The objective of this study is to develop a novel methodology integrating remote sensing, geographic information system technology and local spatial autocorrelation geo–computation for quick drought assessment. One group of drought indices, based on the condition of the vegetation, includes the Normalized Difference Vegetation Index (NDVI), Anomaly of Normalized Difference Vegetation Index (NDVIA) and Standardized Vegetation Index (SVI). The other group, based on the moisture conditions, includes the Normalized Difference Moisture Index (NDMI) and Standardized Moisture Index (SMI). The local G–statistic (Gi*) provides insight into the spatial relationships of the drought indices for drought risk assessment. Specifically, locations with significant Gi* values indicate spatial clusters where there are differences between the vegetative and hydrological drought indices. The results of spatial co–occurrence analysis indicate the existence of hot spots where the drought indices are spatially stable. This spatial information can be used to identify high drought risk areas as a first step towards helping local administrators improve the allocation of local water resources in arid environments. Finally, the novel methodology, integrating remote sensing, geocomputation and geographic information techniques, is demonstrated. The results indicate its effectiveness for quick drought assessment.
اطلاعات انتشار: International Journal Of Environmental Research، نهم،شماره۲، Spring ۲۰۱۵، سال ۰
تعداد صفحات: ۸
The study aimed to investigate the adsorption mechanism of di–n–butyl phthalate (DBP) on brown soil and red soil in Shenyang and Hunan province, respectively, China. Adsorption kinetics and isotherms experiments were conducted at 288, 298 and 308 K, respectively. Results of kinetics showed that adsorption of DBP exhibited a two–step process in both brown and red soil. Different models were used to simulate adsorption isotherms and the linear form of Freundlich model fitted to the data best. Sorption capacity was larger and sorption intensity was weaker on the brown soil than the red at same temperature. Sorption capacity decreased and sorption intensity enhanced with temperature increased on both soils. In addition, the thermodynamic data were analyzed which suggested that the process was a spontaneous and exothermal process on the two soils. The values of enthalpy changes were around 40 kJ\mol in the two soils, indicating that the dominant affection was physical adsorption. Furthermore the main forces were hydrogen bond and ion exchange proved by thermodynamic data and infrared spectral analyses.
۴Removal of Chelated Copper by TiO2 Photocatalysis: Synergetic Mechanism Between Cu (II) and Organic Ligands
اطلاعات انتشار: Iranian Journal of Chemistry and Chemical Engineering (IJCCE)، سي و دوم،شماره۱(پياپي ۶۵)، ۲۰۱۳، سال ۰
تعداد صفحات: ۱۰
UV\TiO2 photocatalysis of chelated copper in aqueous solutions has been performed starting from Cu(II)–tartaric acid, Cu(II)–citric acid, Cu(II)–EDTA and Cu(II)–DTPA, in the presence of oxygen and at acidic pH. The photocatalytic reaction obeys first–order kinetic equation. The inﬂuence of Cu(II) on photocatalytic oxidation of organic ligands and how the various organics will affect the treatment of Cu(II) were described. A significant synergistic effect was observed between the reduction of Cu(II) and oxidation of organic ligands. The results prove that TiO2 photocatalysis is an effective approach for removing chelated copper from wastewater.
اطلاعات انتشار: Iranian Journal of Chemistry and Chemical Engineering (IJCCE)، سي و سوم،شماره۱(پياپي ۶۹)، ۲۰۱۴، سال ۰
تعداد صفحات: ۸
An efficient method for purification of Yard–Glass Shaped Boron Nitride NanoTubes (YG–BNNTs) fabricated via a Chemical Vapour Reaction (CVR) route has been developed. Impurities including carbon, Boron Nitride (BN), and Fe species in the pristine YG–BNNT sample are removed by a combined physical and chemical procedure which involves ultrasonication, high temperature oxidation, hot–water washing and acid washing. The samples at different stages of the purification process are monitored using X–Ray powder Diffraction (XRD), X–ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The results reveal that the carbon and BN impurities could be easily eliminated. However, the catalyst nanoparticles (Fe3C) encaged in the tubes prove to be effectively shielded from oxidation and acid corrosion. Although the content of catalyst nanoparticles could be satisfactorily reduced to about 1.0 wt% by prolonged ultrasonication and acid washing, a small number of such magnetic nanoparticles are still left in the final purified YG–BNNTs. The YG–BNNTs exhibit a typical ferromagnetic behavioureven after a longtime oxidizing and acid washing treatment, indicating that they could be potentially used for harsh–environment magnetic devices.
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