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Author Zhao, Y.; Li, X.; Lei, L.; Chen, L.; Luo, Z. url  openurl
  Title Permeability evolution mechanism and the optimum permeability determination of uranium leaching from low-permeability sandstone treated with low-frequency vibration Type Journal Article
  Year 2023 Publication Journal of Rock Mechanics and Geotechnical Engineering Abbreviated Journal  
  Volume 15 Issue 10 Pages 2597-2610  
  Keywords Chemical reactive rate, Low-frequency vibration, Low-permeability sandstone, Optimum permeability, Permeability evolution mechanism, Uranium migration  
  Abstract Low-frequency vibrations can effectively improve natural sandstone permeability, and higher vibration frequency is associated with larger permeability. However, the optimum permeability and permeability evolution mechanism for uranium leaching and the relationship between permeability and the change of chemical reactive rate affecting uranium leaching have not been determined. To solve the above problems, in this study, identical homogeneous sandstone samples were selected to simulate low-permeability sandstone; a permeability evolution model considering the combined action of vibration stress, pore water pressure, water flow impact force, and chemical erosion was established; and vibration leaching experiments were performed to test the model accuracy. Both the permeability and chemical reactions were found to simultaneously restrict U6+ leaching, and the vibration treatment increased the permeability, causing the U6+ leaching reaction to no longer be diffusion-constrained but to be primarily controlled by the reaction rate. Changes of the model calculation parameters were further analyzed to determine the permeability evolution mechanism under the influence of vibration and chemical erosion, to prove the correctness of the mechanism according to the experimental results, and to develop a new method for determining the optimum permeability in uranium leaching. The uranium leaching was found to primarily follow a process consisting of (1) a permeability control stage, (2) achieving the optimum permeability, (3) a chemical reactive rate control stage, and (4) a channel flow stage. The resolution of these problems is of great significance for facilitating the application and promotion of low-frequency vibration in the CO2 + O2 leaching process.  
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  ISSN (down) 1674-7755 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ zhao_permeability_2023 Serial 198  
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Author Hdeib, R.; Aouad, M. url  openurl
  Title Rainwater harvesting systems: An urban flood risk mitigation measure in arid areas Type Journal Article
  Year 2023 Publication Water Science and Engineering Abbreviated Journal  
  Volume 16 Issue 3 Pages 219-225  
  Keywords Rainwater harvesting, Urban floods, Flood map, Hydrodynamic model, Built environment, Arid areas  
  Abstract Rainwater harvesting (RWH) systems have been developed to compensate for shortage in the water supply worldwide. Such systems are not very common in arid areas, particularly in the Gulf Region, due to the scarcity of rainfall and their reduced efficiency in covering water demand and reducing water consumption rates. In spite of this, RWH systems have the potential to reduce urban flood risks, particularly in densely populated areas. This study aimed to assess the potential use of RWH systems as urban flood mitigation measures in arid areas. Their utility in the retention of stormwater runoff and the reduction of water depth and extent were evaluated. The study was conducted in a residential area in Bahrain that experienced waterlogging after heavy rainfall events. The water demand patterns of housing units were analyzed, and the daily water balance for RWH tanks was evaluated. The effect of the implementation of RWH systems on the flood volume was evaluated with a two-dimensional hydrodynamic model. Flood simulations were conducted in several rainfall scenarios with different probabilities of occurrence. The results showed significant reductions in the flood depth and flood extent, but these effects were highly dependent on the rainfall intensity of the event. RWH systems are effective flood mitigation measures, particularly in urban arid regions short of proper stormwater control infrastructure, and they enhance the resilience of the built environment to urban floods.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN (down) 1674-2370 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Hdeib2023219 Serial 242  
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Author Akter, A.; Tanim, A.H.; Islam, M.K. url  openurl
  Title Possibilities of urban flood reduction through distributed-scale rainwater harvesting Type Journal Article
  Year 2020 Publication Water Science and Engineering Abbreviated Journal  
  Volume 13 Issue 2 Pages 95-105  
  Keywords Low-impact development (LID), SWMM, HEC-RAS, Remote sensing, Urban flooding, Inundation depth  
  Abstract Urban flooding in Chittagong City usually occurs during the monsoon season and a rainwater harvesting (RWH) system can be used as a remedial measure. This study examines the feasibility of rain barrel RWH system at a distributed scale within an urbanized area located in the northwestern part of Chittagong City that experiences flash flooding on a regular basis. For flood modeling, the storm water management model (SWMM) was employed with rain barrel low-impact development (LID) as a flood reduction measure. The Hydrologic Engineering Center’s River Analysis System (HEC-RAS) inundation model was coupled with SWMM to observe the detailed and spatial extent of flood reduction. Compared to SWMM simulated floods, the simulated inundation depth using remote sensing data and the HEC-RAS showed a reasonable match, i.e., the correlation coefficients were found to be 0.70 and 0.98, respectively. Finally, using LID, i.e., RWH, a reduction of 28.66% could be achieved for reducing flood extent. Moreover, the study showed that 10%–60% imperviousness of the subcatchment area can yield a monthly RWH potential of 0.04–0.45 m3 from a square meter of rooftop area. The model can be used for necessary decision making for flood reduction and to establish a distributed RWH system in the study area.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN (down) 1674-2370 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Akter202095 Serial 247  
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Author Rajfur, M.; Kłos, A.; Wacławek, M. url  openurl
  Title Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water Type Journal Article
  Year 2010 Publication Bioelectrochemistry Abbreviated Journal  
  Volume 80 Issue 1 Pages 81-86  
  Keywords Biomonitoring, Heavy metal ions, Algae sp., Sorption kinetics, Langmuir isotherm  
  Abstract Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions – Mn2+, Cu2+, Zn2+ and Cd2+ – were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30min, with 90-95% of metal ions sorbed in first 10min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30min of exposition to contaminated water, the concentration of heavy metal ions in the algae, which initially contained small amounts of these metal ions, increased proportionally to the concentration of metal ions in solution. The presented results can be used for elaboration of a method for classification of surface waters that complies with the legal regulations.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1567-5394 ISBN Medium  
  Area Expedition Conference  
  Notes A Selection of Papers presented at the 4th International Workshop on Surface Modification for Chemical and Biochemical Sensing (SMCBS 2009) Approved no  
  Call Number THL @ christoph.kuells @ Rajfur201081 Serial 283  
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Author Uugulu, S.; Wanke, H. url  openurl
  Title Estimation of groundwater recharge in savannah aquifers along a precipitation gradient using chloride mass balance method and environmental isotopes, Namibia Type Journal Article
  Year 2020 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal  
  Volume 116 Issue Pages 102844  
  Keywords Chloride mass balance, Groundwater recharge, Isotopic values, Precipitation gradient  
  Abstract The quantification of groundwater resources is essential especially in water scarce countries like Namibia. The chloride mass balance (CMB) method and isotopic composition were used in determining groundwater recharge along a precipitation gradient at three sites, namely: Tsumeb (600 mm/a precipitation); Waterberg (450 mm/a precipitation) and Kuzikus/Ebenhaezer (240 mm/a precipitation). Groundwater and rainwater were collected from year 2016–2017. Rainwater was collected monthly while groundwater was collected before, during and after rainy seasons. Rainwater isotopic values for δ18O and δ2H range from −10.70 to 6.10‰ and from −72.7 to 42.1‰ respectively. Groundwater isotopic values for δ18O range from −9.84 to −5.35‰ for Tsumeb; from −10.85 to −8.60‰ for Waterberg and from −8.24 to −1.56‰ for Kuzikus/Ebenhaezer, while that for δ2H range from −65.6 to −46.7‰ for Tsumeb; −69.4 to −61.2‰ for Waterberg and −54.2 to −22.7‰ for Kuzikus/Ebenhaezer. Rainwater scatters along the GMWL. Rainwater collected in January, February and March are more depleted in heavy isotopes than those in November, December, April and May. Waterberg groundwater plots on the GMWL which indicates absence of evaporation. Tsumeb groundwater plots on/close to the GMWL with an exception of groundwater from the karst Lake Otjikoto which is showing evaporation. Groundwater from Kuzikus/Ebenhaezer shows an evaporation effect, probably evaporation occurs during infiltration since it is observed in all sampling seasons. All groundwater from three sites plot in the same area with rainwater depleted in stable isotopic values, which could indicates that recharge only take place during January, February and March. CMB method revealed that Waterberg has the highest recharge rate ranging between 39.1 mm/a and 51.1 mm/a (8.7% – 11.4% of annual precipitation), Tsumeb with rates ranging from 21.1 mm/a to 48.5 mm/a (3.5% – 8.1% of annual precipitation), and lastly Kuzikus/Ebenhaezer from 3.2 mm/a to 17.5 mm/a (1.4% – 7.3% of annual precipitation). High recharge rates in Waterberg could be related to fast infiltration and absence of evaporation as indicated by the isotopic ratios. Differences in recharge rates cannot only be attributed to the precipitation gradient but also to the evaporation rates and the presence of preferential flow paths. Recharge rates estimated for these three sites can be used in managing the savannah aquifers especially at Kuzikus/Ebenhaezer where evaporation effect is observed that one can consider rain harvesting.  
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  ISSN (down) 1474-7065 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ uugulu_estimation_2020 Serial 99  
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Author Alexander, A.C.; Ndambuki, J.M. url  openurl
  Title Impact of mine closure on groundwater resource: Experience from Westrand Basin-South Africa Type Journal Article
  Year 2023 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal  
  Volume 131 Issue Pages 103432  
  Keywords Acid mine drainage, Groundwater quality, Mine closure, Spatio-temporal variation, Westrand Basin  
  Abstract The mining sector is at the edge of expanding to cater for natural resources that are much needed for technological development and manufacturing. Mushrooming of mines will consequently increase the number of mines closure. Moreover, mines closure have adverse impact on the environment at large and specifically on water resources. This study analyses historical groundwater quality parameters in mine intensive basin of Westrand Basin (WRB) to understand the status of groundwater quality in relation to mining activities and mine closure. Geographic information system (GIS) was used to map the spatio-temporal variation of groundwater quality in the basin and groundwater quality index (GQI) to evaluate its status. The coefficient of variation (CV) was applied to understand the stability of groundwater quality after the mine closure. Results indicated unstable and altered trend with increasing levels of acidity and salts concentration around the mines vicinity following the mine closure. The resultant maps indicated a significant deterioration of groundwater quality around the WRB with concentrations decreasing downstream. Obtained average GQI for the study period of 1996–2015 suggested a moderate groundwater quality at a range of GQI = 64–73. The CV indicated varying water quality at CV \textgreater 30% suggesting presence of source of contamination. Observed groundwater quality trends in Westrand basin suggested that mines closure present potential threat on groundwater quality and thus, a need for a robust mine closure plan and implementation.  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ alexander_impact_2023 Serial 134  
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Author Mathuthu, M.; Uushona, V.; Indongo, V. url  openurl
  Title Radiological safety of groundwater around a uranium mine in Namibia Type Journal Article
  Year 2021 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal  
  Volume 122 Issue Pages 102915  
  Keywords Groundwater, ICP-MS, Radiological hazard, Uranium mining  
  Abstract Uranium mining activities produce the main element used in nuclear energy production. However, it can also negatively affect the environment including groundwater by release of residues or effluent containing radioactive elements. The study investigated the concentration and radiological hazard of uranium in groundwater and seepage water from the tailings of a uranium mine in Namibia. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to assess the concentration of uranium in the groundwater and seepage water and the radiological hazards were determined. The radiological hazard indices Radium equivalent activity (Raeq), Absorbed dose (D), Annual Effective Dose equivalent (AEDE), External hazard index (Hex) and Internal hazard index (Hin) were determined and compared to limits recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The calculated average value of D and Hin of groundwater is 108.11nGyh−1 and 1.26, respectively and are above the UNSCEAR values (55 nGyh−1 and 1). Further, the average values of Raeq, AEDE and Hex were below the recommended values. The isotopic ratio of uranium radionuclides in groundwater indicates that the uranium in the sampled groundwater is below 1 suggesting it is not natural uranium present but a possible contamination from the mine seepage. The radiological hazard parameters of the seepage water were above the recommended values and thus pose a radiation risk to human and environment.  
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  ISSN (down) 1474-7065 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ mathuthu_radiological_2021 Serial 160  
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Author Schwiede, M.; Duijnisveld, W.H.M.; Böttcher, J. url  openurl
  Title Investigation of processes leading to nitrate enrichment in soils in the Kalahari Region, Botswana Type Journal Article
  Year 2005 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal  
  Volume 30 Issue 11 Pages 712-716  
  Keywords Nitrate, Arenosol soils, Semi-arid, Kalahari, Cattle, Chloride, Travel time  
  Abstract In Southern Africa elevated nitrate concentrations are observed in mostly uninhabited semi-arid areas. In the Kalahari of Botswana groundwater locally exhibits concentrations up to 600mg/l. It is assumed, that nitrate found in the groundwater originates mainly from nitrogen input and transformations in the soils. Our investigations in the Kalahari between Serowe and Orapa show that cattle raising is an important source for enhanced nitrate concentrations in the soils (Arenosols). But also in termite mounds very high nitrate stocks were found, and under natural vegetation (acacia trees and shrubs) nitrate concentrations were mostly unexpectedly high. This nitrate enrichment in the soils poses a serious threat to the groundwater quality. However, calculated soil water age distributions in the unsaturated zone clearly show that today’s nitrate pollution of the groundwater below the investigation area could originate from natural sources, but cannot be caused by the current land use for cattle raising.  
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  ISSN (down) 1474-7065 ISBN Medium  
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  Notes Integrated Water Resources Management (IWRM) and the Millennium Development Goals: Managing Water for Peace and Prosperity Approved no  
  Call Number THL @ christoph.kuells @ Schwiede2005712 Serial 276  
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Author Jana, A.; Unni, A.; Ravuru, S.S.; Das, A.; Das, D.; Biswas, S.; Sheshadri, H.; De, S. url  openurl
  Title In-situ polymerization into the basal spacing of LDH for selective and enhanced uranium adsorption: A case study with real life uranium alkaline leach liquor Type Journal Article
  Year 2022 Publication Chemical Engineering Journal Abbreviated Journal  
  Volume 428 Issue Pages 131180  
  Keywords In-situ polymerization, Layered double hydroxide, Leach liquor, Uranium adsorption, Uranium recovery  
  Abstract Uranium is used as a fuel for nuclear power plant and can be extracted from different ores, mainly acidic (silicious ore) and alkaline (carbonate ore). Recovery of uranium through acid leaching from silicious ore is well established, whereas, alkaline leaching from carbonate ore is challenging due to the excessive salinity of leach liquor and high concentration of carbonate, bicarbonate and sulphate. Herein, two monomers, acrylic acid (AA) and N, N-methylene bisacrylamide (BAM), selective towards uranyl were intercalated in-situ into the interlayer, followed by their polymerization and cross-linking to form novel polymer intercalated hybrid layered double hydroxide (LDH). The LDH acts as a backbone to overcome coiling and swelling of polymer and anchors them as free-standing. Various parameters, like, the type of metal ions, monomer ratio (AA: BAM) and metal ion ratio (M2+:M3+), were studied to determine the optimum conditions for effective intercalation and polymerization of monomers. Magnesium aluminum (MgAl) LDH with a cross-linked polymer having a monomer ratio of 3:2 (AA: BAM) as intercalating species showed maximum efficiency of uranyl adsorption (1456 mg/g at 30 °C) with highest capacity so far. The distribution coefficient (Kd, l/mg) in the order of 105 suggested that the adsorbent was highly selective for uranyl in the presence of different cations, anions and humic acid. The adsorbent extracts uranium effectively and selectively from a real-life alkaline leach liquor with an efficiency of 96% at 5 g/l dose. Uranium can be recovered from the adsorbent in the form of sodium di-uranate using 2(M) NaOH and was reused for eight cycles.  
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  ISSN (down) 1385-8947 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ jana_-situ_2022 Serial 209  
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Author Rossetto, R.; Filippis, G.D.; Borsi, I.; Foglia, L.; Cannata, M.; Criollo, R.; Vázquez-Suñé, E. url  openurl
  Title Integrating free and open source tools and distributed modelling codes in GIS environment for data-based groundwater management Type Journal Article
  Year 2018 Publication Environmental Modelling & Software Abbreviated Journal  
  Volume 107 Issue Pages 210-230  
  Keywords Free and Open Source Software, FREEWAT, Groundwater management, ICT, MODFLOW, QGIS  
  Abstract Integrating advanced simulation techniques and data analysis tools in a freeware Geographic Information System (GIS) provides a valuable contribution to the management of conjunctive use of groundwater (the world’s largest freshwater resource) and surface-water. To this aim, we describe here the FREEWAT (FREE and open source software tools for WATer resource management) platform. FREEWAT is a free and open source, QGIS-integrated interface for planning and management of water resources, with specific attention to groundwater. The FREEWAT platform couples the power of GIS geo-processing and post-processing tools in spatial data analysis with that of process-based simulation models. The FREEWAT environment allows storage of large spatial datasets, data management and visualization, and running of several distributed modelling codes (mainly belonging to the MODFLOW family). It simulates hydrologic and transport processes, and provides a database framework and visualization capabilities for hydrochemical analysis. Examples of real case study applications are provided.  
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  Series Volume Series Issue Edition  
  ISSN (down) 1364-8152 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ rossetto_integrating_2018 Serial 92  
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