| Records |
| Author |
Hamutoko, J.; Mapani, B.; Ellmies, R.; Bittner, A.; Külls, C. |
Title  |
A fingerprinting method for the identification of uranium sources in alluvial aquifers: An example from the Khan and Swakop Rivers, Namibia |
Type |
Journal Article |
| Year |
2014 |
Publication |
Physics and Chemistry of the Earth, Parts A/B/C |
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| Volume |
72 |
Issue |
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Pages |
34-42 |
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Pergamon |
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THL @ christoph.kuells @ Hamutoko2014fingerprinting |
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19 |
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Naghedifar, S.M.; Ziaei, A.N.; Naghedifar, S.A.; Ansari, H. |
| Title |
A new model for simulation of collection and conveyance sections of Qanat |
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Journal Article |
| Year |
2020 |
Publication |
Journal of Hydrology |
Abbreviated Journal |
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| Volume |
590 |
Issue |
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Pages |
125218 |
| Keywords |
Richards’ equation, Saint-Venant equation, Numerical modeling, Qanat-aquifer system |
| Abstract |
In this paper, a new numerical model has been developed for simulation of Qanat-aquifer system. This model employs quasi-3D mixed-form of Richards’ equation and 1D fully-hydrodynamic form of Saint-Venant equations to simulate subsurface and overland flow, respectively. In order to handle non-orthogonal grids, subsurface flow module benefits from coordinate transformation technique. Using the above-mentioned governing equations, the presented model is able to simulate water flow inside both collection and conveyance sections of the gallery as well as dynamics of groundwater and vadose zone from impermeable bed rock to the soil-air interface. Since measured data corresponding to the hydraulics of Qanats is scarce, the overland and subsurface modules have been validated with analytical, numerical and experimental benchmarks in the literature. Subsequently, the model was employed to simulate ten different hypothetical aquifer-Qanat systems with different properties including the depth of groundwater aquifer, roughness of the gallery and saturated hydraulic conductivity of the gallery-aquifer boundary and the influence of each the parameters was monitored on the outflow rate at the appearance point of each Qanat. Furthermore, the advance of water inside two initially dry galleries were simulated at different time levels up to steady state. Eventually, the streamlines have been shown at the steady state for two Qanat-aquifer systems. Although, the presented study sheds light on some aspects of Qanat-aquifer hydraulics, the validation of the presented model with in-lab or on-field data remains ongoing for the future researches. |
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0022-1694 |
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THL @ christoph.kuells @ Naghedifar2020125218 |
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254 |
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Tan, K.; Li, C.; Liu, J.; Qu, H.; Xia, L.; Hu, Y.; Li, Y. |
| Title |
A novel method using a complex surfactant for in-situ leaching of low permeable sandstone uranium deposits |
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Journal Article |
| Year |
2014 |
Publication |
Hydrometallurgy |
Abbreviated Journal |
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| Volume |
150 |
Issue |
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Pages |
99-106 |
| Keywords |
Complex surfactant, In-situ leaching of uranium mining, Leaching kinetics, Low permeable sandstone uranium deposit, Resin adsorption and elution |
| Abstract |
Applications of a complex surfactant developed in-house to in-situ leaching of low permeable sandstone uranium deposits are described based on results from agitation leaching, column leaching, resin adsorption, and elution experiments using uranium containing solution from the in-situ leaching site. The results of agitation leaching experiments show that adding surfactant with different concentrations into leaching solution improves the leaching rate of uranium. The maximum leaching rate of uranium from agitation leaching reached 92.6% at an added surfactant concentration of 10mg/l. Result of column leaching experiment shows that adding surfactant with varying concentrations into leaching solutions increased the permeability coefficient of ore-bearing layer by 42.7–86.8%. The leaching rate of uranium from column leaching increased by 58.0% and reached 85.8%. The result of kinetic analysis shows that for the extraction of uranium controlled by diffusion without surfactant the apparent rate constant 0.0023/d changed to 0.0077/d for the extraction with surfactant controlled by both diffusion and surface chemical reactions. Results from resin adsorption and elution experiments show that there was no influence on resin adsorption and elution of uranium with an addition of 50mg/l surfactant to production solution from in-situ leaching. The adsorption curve, sorption capacity of resin, recycling of resin remained the same as without adding any surfactant. Introducing complex surfactant to leaching solution increased the peak concentration of uranium in eluents, reduced the residual uranium content in resin, and promoted the elution efficiency. The method of using a complex surfactant for in-situ leaching is useful for low permeable sandstone uranium deposits. |
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0304-386x |
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THL @ christoph.kuells @ tan_novel_2014 |
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201 |
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Heidari, B.; Prideaux, V.; Jack, K.; Jaber, F.H. |
| Title |
A planning framework to mitigate localized urban stormwater inlet flooding using distributed Green Stormwater Infrastructure at an urban scale: Case study of Dallas, Texas |
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Journal Article |
| Year |
2023 |
Publication |
Journal of Hydrology |
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621 |
Issue |
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Pages |
129538 |
| Keywords |
Green stormwater infrastructure, Localized inlet pluvial flooding, Opportunity subwatersheds, Stormwater investment prioritization, Resilient urban watershed planning |
| Abstract |
Mitigation of localized pluvial flooding is one of the major resiliency goals in urban environments, and Green Stormwater Infrastructure (GSI) has the potential to deliver such an outcome. However, there is a lack of systematic approaches to prioritize investment in different candidate areas. This study provides a framework to identify vulnerable stormwater drainage inlets and their contributing areas, prioritize them, identify dominant factors in their selection, assess the potential of GSI in mitigating their overflows, and compare the impact and its cost to gray infrastructure upgrade alternatives. Using SWMM 5.1.013, decision trees, and a volumetric-based assessment of GSI overflow capture, we applied the framework to the City of Dallas, Texas, for three design storms with three GSI practices— bioretention cells, raingardens, and rainwater harvesting tanks. Results showed that there was a significant increase in the number of overflowing stormwater drainage inlets, referred to as hotspots, and their contributing subwatersheds, referred to as opportunity areas, with more intense storms especially in problematic watersheds. Also, prioritization results provided a series of maps to rank the opportunity areas based on overflow severity, recurrence of the overflows, and GSI availability. Moreover, classification results showed that inlet features, especially the inlet depth, were the dominant factors in the identification of the non-problematic inlets. Finally, the GSI impact assessment showed substantial overflow mitigation even at the “very high” severity levels when GSI is comprehensively deployed across opportunity areas. Despite gray infrastructure upgrades yielding higher reduction levels, their cost per cubic meter was higher than GSI. Therefore, a combination of GSI and gray results in maximum overflow reduction at a lower cost compared to common practices. |
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0022-1694 |
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THL @ christoph.kuells @ Heidari2023129538 |
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226 |
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Garvelmann, J.; Külls, C.; Weiler, M. |
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A porewater-based stable isotope approach for the investigation of subsurface hydrological processes |
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Journal Article |
| Year |
2012 |
Publication |
Hydrology & Earth System Sciences |
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16 |
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2 |
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THL @ christoph.kuells @ Garvelmann2012porewater |
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24 |
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