| 2. |
- Faisal, Ayad A. H, et al.
(author)
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Controlling metal ion migration in contaminated groundwater with Iraqi clay barriers for water resource protection
- 2023
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In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 13:24, s. 16196-16205
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Journal article (peer-reviewed)abstract
- This study investigates the effectiveness of using Iraqi clay as a low-permeability layer to prevent the migration of lead and nickel ions in groundwater-aquifers. Tests of batch operation have been conducted to determine the optimal conditions for removing Pb2+ ions, which were found to be 120 minutes of contact time, a pH of 5, 0.12 g of clay per 100 mL of solution, and an agitation of 250 rpm. These conditions resulted in a 90% removal efficiency for a 50 mg L−1 initial concentration of lead ions. To remove nickel ions with an efficiency of 80%, the optimal conditions were 60 minutes of contact time, a pH of 6, 12 g of clay per 100 mL of solution, and an agitation of 250 rpm. Several sorption models were evaluated, and the Langmuir formula was found to be the most effective. The highest sorption capacities were 1.75 and 137 mg g−1 for nickel and lead ions, respectively. The spread of metal ions was simulated using finite element analysis in the COMSOL multiphysics simulation software, taking into account the presence of a clay barrier. The results showed that the barrier creates low-discharge zones along the down-gradient of the barrier, reducing the rate of pollutant migration to protect the water sources.
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| 3. |
- Henriksson, Mikael, 1996-, et al.
(author)
-
An Architecture for Grant-Free Random Access Massive Machine Type Communication Using Coordinate Descent
- 2020
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In: Proceedings of Fifty-Fourth Asilomar Conference on Signals, Systems and Computers. - Pacific Grove, CA, USA : IEEE. - 9781665447072 - 9780738131269 ; , s. 1112-1116
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Conference paper (peer-reviewed)abstract
- An implementation of activity detection for grant-free massive machine type communication is presented. The implemented algorithm is based on coordinate descent which shows a rapid convergence time. A number of modifications to the original algorithm is proposed to allow efficient implementation in hardware. In addition, the implementation is based on fixed-point representation, and, hence, exhaustive word length simulations have been performed for the different processing steps.
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