| 1. |
- Arsenlis, Athanasios, et al.
(författare)
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Enabling strain hardening simulations with dislocation dynamics
- 2007
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Ingår i: Modelling and Simulation in Materials Science and Engineering. - : IOP Publishing. - 0965-0393 .- 1361-651X. ; 15, s. 553-595
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Tidskriftsartikel (refereegranskat)abstract
- Numerical algorithms for discrete dislocation dynamics simulations areinvestigated for the purpose of enabling strain hardening simulations of singlecrystals on massively parallel computers. The algorithms investigated includethe O(N) calculation of forces, the equations of motion, time integration,adaptive mesh refinement, the treatment of dislocation core reactions and thedynamic distribution of data and work on parallel computers. A simulationintegrating all these algorithmic elements using the Parallel DislocationSimulator (ParaDiS) code is performed to understand their behaviour in concertand to evaluate the overall numerical performance of dislocation dynamicssimulations and their ability to accumulate percent of plastic strain.
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| 2. |
- Xu, Jingzhe, et al.
(författare)
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Geochemistry of soils derived from black shales in the Ganziping mine area, western Hunan, China
- 2013
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Ingår i: Environmental Earth Sciences. - : Springer Science and Business Media LLC. - 1866-6280 .- 1866-6299. ; 70:1, s. 175-190
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Tidskriftsartikel (refereegranskat)abstract
- The geochemistry of major and trace elements (including heavy metals and rare earth elements) of the fresh and weathered black shales, and the soils derived from black shales in the Ganziping mine area in western Hunan province (China) were studied using the following techniques: X-ray fluorescence (XRF), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray diffraction (XRD). The results show that the black-shale soils are significantly enriched with Al2O3 and Fe2O3, and depleted of mobile elements CaO, Na2O and K2O. The soils are also highly enriched with heavy metals U, V, Ni, Ba, Cu, Zn and Pb, that may cause potential heavy-metal contamination of the soils. Composition of the soils is homogeneous compared to the weathered black shales, for which the concentrations of major elements except CaO and Na2O, and trace elements except heavy metals (U, V, Ni, Ba, Cu, Zn and Pb) as well as the mobile Sr, show lower variations than in the weathered black shales. Ratios of Zr/Hf, Ta/Nb, Y/Ho, Nd/Sm, and Ti/(Ti + Zr), of the soils are also less variable, with values constantly similar to that of the fresh and weathered black shales correspondingly. Thus, components of the soils are believed to be contributed from the parent black shales through weathering and pedogenesis. It is concluded that the soils were formed by at least two stages of geochemical processes: the early stage of chemical differentiation and the later stage of chemical homogenization. The chemical differentiation that was taken during black-shale weathering might have caused the depletion of CaO and Na2O, and the enrichment of Al2O3 and Fe2O3; while the chemical homogenization that was taken during pedogenesis led to the depletion of SiO2 and K2O, and to the further enrichment of Al2O3 and Fe2O3. The heavy-metal enrichment (contamination) of the soils was then genetically related to the enrichment of Al2O3 and Fe2O3 in the soils.
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