The different morphologies of CuCo2S4 have a significant effect on the electrocatalytic activity. However, the reasons for the activity difference of catalysts with multiple morphologies have raised little concern. Herein, we put forward the concept of “active edge perimeter” to evaluate the relative number of active sites. The morphologies are regulated by arranging NH4F from 0 to 3 mmol to prepare microsheet, tight‐binding microsheet, hybrid microsheet/wire, long microwire and short wire morphologies. The long‐perimeter microsheets can achieve a low Tafel slope (89 mV dec−1) and overpotential (283 mV) to reach a current density of 20 mA cm−2 for the oxygen evolution reaction. For microsheets, the charge‐transfer resistance is well under 50 % of the average values. The electrochemical surface area is above average area, owing to the high double‐layer capacitance. Therefore, for two‐dimensional microsheets, the long active perimeter is the main reason it ensures the high activity required for hierarchical catalysts.
The main canal of the middle route of the South-to-North Water Diversion Project has the risk of excess head loss in crossing water-conveyance structures, but the assessment of this risk faces difficulties such as the lack of sufficient monitoring points inside the structures, the current water-conveyance flow rate being lower than the design maximum flow rate, and the lack of verification of monitoring data. Monitoring data of the main canal were collected in 2022, prototype observations were carried out, the monitoring data were verified, and a method for calculating the head loss using the combined head loss coefficient was proposed. The assessment of 143 structures showed that 40 structures had excess head losses, including 31 inverted siphons, four aqueducts, four underdrains, and one culvert. The 143 structures had a total residual head of 3.05 m, accounting for 9% of the distributed head. In addition to natural aging, freshwater mussel and algal attachment, sediments, and undesirable flow regimes were all important influencing factors that caused the head loss to increase. It is recommended to take measures such as regular removal of sediments and algae and freshwater mussel attachments, optimization of inlet and outlet shapes, and application of roughness-reducing materials.
The behavior of electron transfer and ion transport plays as ignificant role in the electrocatalytic activity. However,t he improvemento fC uCo 2 S 4 electrocatalytic activity has been ad ifficult problem owing to lack of effective electron transfer and ion transport. Herein, the unique structure connected CuCo 2 S 4 nanosheets andc arbon cloth (CC) with Fe 2 O 3 nanoparticles to form CuCo 2 S 4 /Fe 2 O 3 /CC. Comparedw ith CuCo 2 S 4 /CC, the resistances of electron transfer and ion transport were decreased by 65 and 84 %, respectively.T he electrochemical surfacea rea of CuCo 2 S 4 / Fe 2 O 3 /CC was2 .76 times larger than that of CuCo 2 S 4 /CC due to the high double-layerc apacitance. For the oxygen evolution reaction, CuCo 2 S 4 /Fe 2 O 3 /CC could achieve an overpotential of 273 mV and aT afel slope of 67 mV dec À1 in alkaline solution.
The extreme shallow-water waves during a tropical cyclone are often simplified to solitary waves. Considering the lack of simulation tools to effectively and efficiently forecast wave forces on coastal box-girder bridges during tropical cyclones, this study investigates the impacts of solitary waves on box girders and accordingly develops a fast prediction model for solitary wave forces. Computational fluid dynamics (CFD) simulations are used to simulate the hydrodynamic forces on the bridge deck. A total of 368 cases are calculated for the parametric study by varying the submergence coefficients (Cs), relative wave heights (H/h) and deck aspect ratios (W/h). With the CFD simulation results as the training datasets, an artificial neural network (ANN) is trained utilizing the back-propagation algorithm. The maximum wave forces first increase and then decrease with the Cs, while they monotonically increase with H/h. For relatively large H/h and small Cs values, the relationship between the maximum wave forces and W/h presents strong nonlinearities. The observed correlation coefficients between the ANN predictions and the CFD results for the vertical and horizontal wave forces are 98.6% and 98.1%, respectively. The trained ANN-based model shows good prediction accuracy and could be used as an efficient model for the tropical cyclone risk analysis of coastal bridges.
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