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Introduction: This study investigates the displacement of two miscible fluids within an inclined porous medium at the pore scale, highlighting how the pore-scale microstructure, inclination angle, and viscosity ratio affect the interfacial instability between two fluids during displacement processes. Methods: The lattice Boltzmann Method (LBM) is employed to solve the governing equations. Two distribution functions are used to simulate the velocity field and the concentration field, respectively. Results and discussion: An increase in inclination angle exacerbates the interfacial instability between fluids and the viscous fingering phenomenon. This viscous fingering expands the sweep range of displacing fluids, which improves the displacement efficiency. When θ≥ 50°, further increase in inclination angle will not cause significant changes in displacement efficiency. In addition, the viscosity ratio is a key factor affecting displacement efficiency. The larger the viscosity ratio, the greater the displacement efficiency. Furthermore, the critical viscosity ratio has been found, and any increase in the viscosity ratio above the critical value will not affect the displacement efficiency. [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) were used as admixtures to modify traditional concrete, and carbon nanofibers reinforced concrete (CNFC) with fiber volume fraction of 0%, 0.1%, 0.2%, 0.3% and 0.5% were prepared. The dynamic splitting tensile tests of concrete with different fiber volume contents under five loading rates were carried out by using the Φ100 mm split Hopkinson pressure bar (SHPB) test device. Based on the observation and analysis of the failure modes of the specimens, combined with the energy change rate of incident wave, the failure characteristics of CNFC under dynamic splitting tensile load are expounded. The results show that: the addition of CNFs has a certain inhibition effect on the dynamic splitting tensile failure of concrete; the failure modes of the specimens are the central failure along the loading direction; with the increase of the energy change rate of incident wave, the damage degree of the specimen is gradually aggravated.

The Electro-Fenton (E-Fenton) technique has shown great potential in wastewater treatment, while the sustainable and continuing supply of Fe2+ remains challenging. Herein, we demonstrate the construction of a novel E-Fenton system by magnetically decorating zero-valent iron (ZVI) onto a RuO2-IrO2/Ti (ZVI-RuO2-IrO2/Ti) electrode for high-efficient treatment of pharmaceutical wastewater, which is considerably refractory and harmful to conventional biological processes. By using ZVI as a durable source of Fe(II) irons, 78.69% of COD and 76.40% of TOC may be rapidly removed by the developed ZVI-RuO2-IrO2/Ti electrode, while the ZVI-RuO2-IrO2/Ti electrode using ZVI only reduces 35.64% of COD under optimized conditions at initial COD and TOC values of 5500 mg/L and 4300 mg/L, respectively. Moreover, the increase in BOD5/COD from 0.21 to 0.52 highlights the enhanced biodegradability of the treated effluent. The analysis of a simultaneously formed precipitation on electrodes suggests that the coagulation process dominated by Fe3+/Fe2+ also plays a non-negligible role in pharmaceutical wastewater treatment. In addition, the monitoring of the evolution of nitrogen elements and the formation of by-products in the E-Fenton process verifies its great capacity toward those organic pollutants found in pharmaceutical wastewater. Our study offers a practical solution for enhancing the performance of E-Fenton systems, and effectively treating refractory pharmaceutical wastewater. [ABSTRACT FROM AUTHOR]

The solid particles with different sizes exist widely, like cell separation, food processing, water treatment, thus, investigating the motion of the solid particles with different sizes is important. This study investigates the motion of a pair of neutrally buoyant circular particles with different sizes in a lid-driven square cavity using the lattice Boltzmann method. The motion of the circular particles with different sizes and that of the circular particles with identical sizes are quite different. The steady trajectories of the circular particles with identical sizes are identical, which is not affected by the Reynolds number. Differently, the circular particles with different sizes orbit along different steady trajectories, namely, the steady trajectory of the small particle is closer to the walls of the square cavity, while that of the large particle shrinks toward the center of the square cavity, which may provide us a possible method to separate them. However, it is not always effective, if the Reynolds number is low, the velocity difference between the circular particles with different sizes is small, which may fail to separate them completely. [ABSTRACT FROM AUTHOR]