Biodiversity and temporal patterns of macrozoobenthos in a coal mining subsidence area in North China

Coal resources play a strategic role in the long-term development of China. Large-scale mining has a considerable impact on the landscape, and it is a long-term heritage of industrialization unique to the Anthropocene. We investigated the macrozoobenthos and water in nine mining subsidence wetlands at different developmental stages (3–20 years) in North China. A total of 68 species were found, and the macrozoobenthos community in the newly formed wetlands showed high diversity. We believe that this high diversity is not random; rather, the high diversity was because of the special origin and development of the wetland. We used three time slices from the timeline of the development of the newly formed wetlands and compared them. It was found that the macrozoobenthos community was significantly affected by the change in the subsidence history. We emphasize that coal mining subsidence should not be merely identified as secondary man-made disasters, as they are often secondary habitats with high conservation value, and their conservation potential lies in the fact that these secondary habitats can replace rapidly decreasing natural wetlands

Phytoextraction potential of wetland plants for Copper in Water Bodies

Luo, Z., Yuan, X, Chen, X., & Cui, X. (March-April, 2017). Phytoextraction potential of wetland plants for Copper in Water Bodies. Water Technology and Sciences (in Spanish), 8(2), 43-50. Copper is the most common heavy metal contaminant in the environment. Wetland construction engineering and technology have been used to control water pollution due to their low cost and efficiency and the hydrophytes have been the most important constituents of wetland construction. In this experiment, during April of 2014, Cu2+ accumulation content in different parts of Acorus calamus and Phragmites australis were investigated based on hydroponic experiments of different Cu2+ concentration solutions. Cu2+ concentrations in the water body were 0, 10, 25, 60, 100, 200 and 500 mg/l, respectively. The results showed that there were significant Cu2+ concentration differences between the above- and below-ground parts of Acorus calamus and Phragmites australis. Cu2+ content in the above- and belowground parts of wetland plants increased with hydroponic solution Cu2+ concentrations, resulting in a significantly positive correlation between Cu2+ content and concentrations of hydroponic solutions. There was a significant difference in Cu2+ content in the wetland plants under all hydroponic solution Cu2+ concentrations. Acorus calamus exhibited the greatest Cu2+ accumulation in above- and below-ground parts. Acorus calamus and Phragmites australis can be selected for application on the phytoremediation of water polluted by heavy metals due to their excellent Cu2+ accumulation ability

Direct chemical synthesis of L1\u3csub\u3e0\u3c/sub\u3e-FePtAu nanoparticles with high coercivity

We report a facile synthesis of hard magnetic L10-FePtAu nanoparticles by coreduction of Fe(acac)3, Pt(acac)2 (acac = acetylacetonate), and gold acetate in oleylamine. In the current reaction condition, NP sizes are controlled to be 5.5 to 11.0 nm by changing the amount of Au doping. When the Au composition in the NPs is higher than 14%, the hard magnetic NPs are directly obtained without any annealing. The highest coercivity of 12.15 kOe at room temperature could be achieved for the NPs with 32% Au doping, which is much higher than the coercivities reported by the previous studies on solution-synthesized FePt nanoparticles. The reported one-pot synthesis of L10-FePtAu NPs may help to build superstrong magnets for magnetic or data-storage applications

The nonlinear variation of drought and its relation to atmospheric circulation in Shandong Province, East China

Considerable attention has recently been devoted to the linear trend of drought at the decadal to inter-decadal time scale; however, the nonlinear variation of drought at multi-decadal scales and its relation to atmospheric circulation need to be further studied. The linear and nonlinear variations of the Palmer drought severity index (PDSI) in Shandong from 1900 to 2012 and its relations to the Pacific decadal oscillation (PDO), El Niño-Southern Oscillation (ENSO), Siberian high (SH) and Southern Oscillation (SO) phase changes from multi-scale are detected using linear regression, the Mann–Kendall test, ensemble empirical mode decomposition (EEMD) and the Pearson correlation analysis method. The results indicate that the PDSI shows no statistically significant linear change trend from 1900 to 2012; however, before (after) the late 1950s, PDSI shows a significant upward (downward) trend (P < 0.01) with a linear rate of 0.28/decade (−0.48/decade). From 1900 to 2012, the PDSI also exhibits a nonlinear variation trend at the inter-annual scale (quasi-3 and quasi-7-year), inter-decadal scale (quasi-14-year) and multi-decadal scale (quasi-46 and quasi-65-year). The variance contribution rate of components from the inter-annual scale is the largest, reaching 38.7%, and that from the inter-decadal scale and multi-decadal scale are 18.9% and 19.0%, respectively, indicating that the inter-annual change exerts a huge influence on the overall PDSI change. The results also imply that the effect of the four atmospheric circulations (PDO, ENSO, SH, SO) on PDSI at the multi-decadal variability scale are more important than that at the other scales. Consequently, we state that PDSI variation at the inter-annual scale has more instability, while that at the inter-decadal and multi-decadal scale is more strongly influenced by natural factors

Numerical Investigation of Fluid Flow and Performance Prediction in a Fluid Coupling Using Large Eddy Simulation

Large eddy simulation (LES) with various subgrid-scale (SGS) models was introduced to numerically calculate the transient flow of the hydraulic coupling. By using LES, the study aimed to advance description ability of internal flow and performance prediction. The CFD results were verified by experimental data. For the purpose of the description of the flow field, six subgrid-scale models for LES were employed to depict the flow field; the distribution structure of flow field was legible. Moreover, the flow mechanism was analyzed using 3D vortex structures, and those showed that DSL and KET captured abundant vortex structures and provided a relatively moderate eddy viscosity in the chamber. The predicted values of the braking torque for hydraulic coupling were compared with experimental data. The comparison results were compared with several simulation models, such as SAS and RKE, and SSTKW models. Those comparison results showed that the SGS models, especially DSL and KET, were applicable to obtain the more accurate predicted results than SAS and RKE, and SSTKW models. Clearly, the predicted results of LES with DSL and KET were far more accurate than the previous studies. The performance prediction was significantly improved

The evaluation of wetland reconstruction with nature-based solutions for eco-economic sustainable development

Nature-based solutions (NBS) are effective approaches for solving ecological and economic problems related to wetland reconstruction, while emergy and exergy are well suited for evaluating reconstructed eco-economic systems. In this paper, we executed a wetland reconstruction project involving a mulberry-fir woodland and dike-pond complex (MFWDPC) with NBS in the water-level fluctuation zone of the Three Gorges Reservoir (TGR), China. We evaluated the coupling mode of this eco-economic system by using emergy and exergy theories. After wetland reconstruction, the emergy density that entered the MFWDPC was 1.48E + 18 sej yr−1 hm−2, in which the naturally renewable flow accounted for 96.31 % of the emergy inflows, and the emergy sustainability index (ESI) for the eco-economic system was 708.88. The exergy and specific exergy were 2.41E + 14 j yr−1 and 2.08E + 08 j yr−1 kg−1, respectively, and the emergy/exergy ratio was 1.55E + 03 for the MFWDPC. In addition, mulberry trees with strong flooding tolerance provided good economic benefits due to the use of these plants in reconstructed eco-economic systems. Our study of NBS for wetland reconstruction helps in understanding the synergistic symbiosis between ecosystems and economic systems, thereby promoting the reconstruction of degraded wetlands in China and other regions