Developing new uses of CO2 and renewable energy technology is crucial for CO2 mitigation, which can be realized simultaneously through the synthesis of advanced functional carbon materials using CO2 as a carbon source. Herein, an oxygenated alkynyl carbon material (OACM) was synthesized via the solvent-free mechanochemical reaction of CaC2 and CO2 under mild conditions, and its electrochemical performance as a supercapacitor electrode was investigated. The gas–solid reaction here is efficient and cost effective owing to the mechanical activation of CaC2. The resultant nanosized OACM features a 3D structure with alkynyl-linked oxygenated carbon chains, hierarchical porosity, numerous defects, high oxygen content, and polycrystalline state. The OACM exhibits high electrochemical performance, including a high specific capacitance (121.8 F g–1 under 0.15 A g–1), superior electrical conductivity (1522 S m–1), and excellent cycling stability (above 96.6% in 5000 cycles) due to its unique structure. This work provides a new CO2 use and an innovative synthesis approach for high-performance alkynyl carbon materials.

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A semi–implicit numerical model with a linear solver is proposed for the free-surface and pressurized mixed flows in hydraulic systems. It solves the two flow regimes within a unified formulation, and is much simpler than existing similar models for mixed flows. Using a local linearization and an Eulerian–Lagrangian method, the new model only needs to solve a tridiagonal linear system (arising from velocity-pressure coupling) and is free of iterations. The model is tested using various types of mixed flows, where the simulation results agree with analytical solutions, experiment data and the results reported by former researchers. Sensitivity studies of grid scales and time steps are both performed, where a common grid scale provides grid-independent results and a common time step provides time-step-independent results. Moreover, the model is revealed to achieve stable and accurate simulations at large time steps for which the CFL is greater than 1. In simulations of a challenging case (mixed flows characterized by frequent flow-regime conversions and a closed pipe with wide-top cross-sections), an artificial slot (A-slot) technique is proposed to cope with possible instabilities related to the discontinuous main-diagonal coefficients of the linear system. In this test, a slot-width sensitivity study is also performed, and the suitable slot-width ratio (ε) for the linear solver is suggested to be 0.05–0.1.

Spillway is an important flood control facility for hydraulic architectures, whether the design and layout of the spillway are reasonable or not can directly affect the safety of hydraulic architectures and the investment of the entire project. To discuss the rationality of the designed reinforcement scheme for spillway of Goushuipo Reservoir in China, this paper employed the Computational Fluid Dynamics (CFD) methods, Volume of Fluid (VOF) model and Re-Normalization Group (RNG) model to simulate the water surface line of spillway under different verified flood standard conditions based on the measured data of water surface line of spillway of the Goushuipo Reservoir. By comparing with the test values, it’s verified that the simulation results are of high accuracy; then on this basis, this paper analyzed the relationship between water level and water flow of spillway under different conditions and other hydraulic performance such as the water flow state. Moreover, according to the simulation results, this paper analyzed the problems with the original design scheme and further proposed an optimized scheme: the two-step water-drop energy dissipation scheme for the Goushuipo Reservoir, and performed numerical simulation on the optimized scheme. At last, the simulation results proved the rationality of the optimized scheme, and the research findings of this paper provide useful references for the reinforcement project of the target reservoir in the future.