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Surface sediments and sediment cores in a shallow eutrophic lake, Chaohu Lake, were analyzed by P-31-NMR to reveal the phosphorus (P) species and their effects on upper water quality. Total P (TP) in the NaOH-EDTA extracts was dominated by inorganic phosphate (P-i), with higher levels being observed in the heavily eutrophic western lake (79.1 +/- 1.7%) than in the eastern lake (68.1 +/- 2.4%). These findings were opposite to those for organic phosphorus (P-o). P-i (ortho-phosphate and pyrophosphate) and P-o (phosphonates, ortho-phosphate monoesters and phospholipids, DNA) were detected in the NaOH-EDTA extracts of the sediments by P-31-NMR. The majority of P-o consisted of ortho-phosphate monoesters (80.2 +/- 2.7%). For sediment cores, the contents of phospholipids and DNA declined more rapidly than that of ortho-phosphate monoesters and pyrophosphate as sediment depth increased, with these compounds primarily occurring in the top 10 cm of sediment. The positive relationship between P-o in sediment and TP in the water showed that P-o compounds in the sediment would be released to the water. These compounds of P-o will be mineralized to P-i and potentially bioavailable for recycling to surface water, supporting further growth of aquatic organisms and leading to algal blooms.

Bulge forming (BF) processes as a metal working operation has received comprehensive investigation. The process and its products have been widely used in many areas. However, there are few papers published to deal with plastic BF (the application of BF technique to polymer processing, PBF). Compared to conventional polymer processing such as extrusion, injection moulding and blow moulding processes, the PBF process is relatively new, and therefore, there is no extensive knowledge base for tool and process design. This paper reviews the progress and features of the BF process and discusses the feasibility and necessity of PBF. In addition, the relationship between process variables and achievable part geometry and mechanical performance are investigated.

Obtaining two-dimensional distributions of reactive phosphorus in sediment porewater is very important for understanding fine-scale phosphorus mobilization and sequestration processes in sediments. In this study, the diffusive equilibrium in thin films (DET) measurement based on computer imaging densitometry (CID) was studied in detail with optimal conditions described. This study focuses on evaluating the two-dimensional colorimetric DET method coupled with CID (DET-CID method) for porewater labile phosphate measurements.The result shows that the red channel filter is the optimum channel for sensitivity to process the image. Additionally,staining time and temperature have great influence on the method, and 20 min staining time and ≥25 ◦C staining temperature were recommended. The minimum detection limit of labile phosphate of this method was0.300 mg P/L, and the maximum detection limit could reach 50.00 mg P/L. The DET-CID technique can be used to measure labile phosphate in a wide range of acidic and alkaline water bodies (pH = 2–10 and water hardness from 0 to 2000 mg/L as CaCO3). The linear regression analysis shows that this technique presents very similar results compared with other two existing methods (R2 = 0.999). Our results would give insights into the precisely measurements of labile phosphate in field applications Refereed/Peer-reviewed

Evaluation of in situ capping with biochar (BC) to control ammonia nitrogen (NH₄⁺-N) release from the sediments of Baiyangdian Lake, the largest freshwater lake in northern China, was performed after 10 months of field and mesocosm experiments. The concentration of NH₄⁺-N in pore water and its resupply from native sediments and capped sediments were determined using the technique of diffusive equilibrium in thin films (DET) and the technique of diffusive gradients in thin films with CMI-7000 cation ion exchange membrane (CMI-DGT) binding layer. The results showed a low concentration of NH₄⁺-N in pore water and a low resupply from the sediment or capping materials after BC capping. The concentration of bioavailable NH₄⁺-N measured by DGT of the top 4 cm layer in BC capping layer was only 12.8%−29.2% of the native sediments. Flux DET-NH₄⁺-N, could be reduced from 12.74 to 3.44 mg·m⁻²·d−1 and Flux DGT-NH₄⁺-N was further reduced from 13.38 to 1.59 mg·m⁻²·d−1. The calculated concentration gradient at the sediment-water interface following the capping treatment was lower than the control. These results implied that BC capping reduced the release of NH₄+-N from the sediments. The low resupply from the sediments was further demonstrated by the smaller ratio of CDGT- to CDET (R) in the BC capping layer, which their average values were 0.48, 0.59, 0.68 in the BC capping layer, BC/soil layer and native sediments, respectively. The physical, chemical and microbiological effects were attributed to inhibit the NH₄⁺-N release from sediments by the BC capping. Refereed/Peer-reviewed