It is of great significance to study shale apparent permeability under the action of multiple flow mechanisms and factors because shale reservoirs possess complex pore structures and flow mechanisms. In this study, the confinement effect was considered, with the thermodynamic properties of gas being modified, and the law relating to the conservation of energy adopted to characterize bulk gas transport velocity. On this basis, the dynamic change of pore size was assessed, from which shale apparent permeability model was derived. The new model was verified by three steps: experimental and molecular simulation results of rarefied gas transport, shale laboratory data, and comparison with different models. The results revealed that, under the conditions of low pressure and small pore size, the microscale effects became obvious, which significantly improved gas permeability. Through comparisons, the effects of surface diffusion and matrix shrinkage, including the real gas effect, were obvious in the smaller pore sizes; nevertheless, the stress sensitivity effect was stronger in larger pore sizes. In addition, shale apparent permeability and pore size decreased with an increase in permeability material constant and increased with increasing porosity material constant, including internal swelling coefficient. The permeability material constant had the greatest effect on gas transport behavior in nanopores, followed by the porosity material constant; however, the internal swelling coefficient had the least effect. The results of this paper will be important for the prediction and numerical simulation of apparent permeability relating to shale reservoirs.

The environment of coal reservoirs is complex and variable, with various factors, not independent, but interlocking and coupled. However, their coupling effects have rarely been considered in previous theoretical studies. In addition, when a fractal theory was applied to analyze the permeability of coal, the linkage between fractal dimensions and the pore radius under external factors has usually been ignored. In this study, two parameters, pore compressibility and dynamic water saturation, were introduced to quantitatively represent the internal interactions between stress and water. Based on the results, dynamic fractal dimensions under the coupling actions of stress and water were obtained by considering variation in the pore radius and the assignment status of gas and water, following which an apparent permeability model of coal, with dynamic fractal dimensions, was established. The newly developed model was verified by reference to published experimental data. The results showed that stress dominated changes in the fractal dimension for pore-size distribution under the coupling actions of stress and water; however, changes in the fractal dimension for tortuosity was dominated, in turn, by stress and water. Subsequently, it was found that the fractal apparent permeability model could match the experimental data well. It revealed that the newly developed model could predict the evolution of coal permeability under dynamic changes in stress and water. Further, under the coupling actions of stress and water, the apparent permeability of coal possessed a positive correlation with the fractal dimension for pore-size distribution or water-dominated fractal dimension for tortuosity, while it was negatively correlated with the critical capillary radius or stress-dominated fractal dimension for tortuosity. In addition, the evolution of the apparent permeability was consistent with specific fractal dimensions and dynamic fractal dimensions, but the evolution of the slippage factor revealed an opposite result. Consequently, this initiates a new analytical perspective into investigating change mechanisms relating to coal permeability.

TiP 2 O 7 and carbon-coated TiP 2 O 7 were successfully synthesized via a rapid microwave method and were electrochemically tested in 1 M Li 2 SO 4 aqueous electrolyte. Physical properties were characterized through X-ray diffraction, thermal gravimetric analysis, scanning electron microscopy, and transmission electron microscopy. The relationship between processing parameters (graphite concentration, ball mill duration, microwave energy input, heating duration) and the final products' electrochemical performance was studied. Full cell tests with LiMn 2 O 4 cathode materials were also tested to obtain cycling stability and rate performance results. The highest specific capacity of C-TiP 2 O 7 was 109 mAh g-1 (90.1% of the theoretical capacity) from the cyclic voltammetry test with the scan rate of 0.3 mV s-1. After 200 cycles under the rate of 0.5C, the C-TiP 2 O 7 's capacity still maintained 92% of the initial capacity. These results suggested that the rapid microwave synthesis method is a promising process to synthesis the electrode materials with excellent electrochemical performances. K E Y W O R D S anode material, aqueous rechargeable lithium-ion batteries, energy storage, rapid processing technology 1 INTRODUCTION Lithium-ion batteries are playing a significant role in electronic products like smartphones, laptops, digital cameras, portable music players. [1] Rüetschi has come up with the "three E" criteria: Energy, Economics, and Environment, [2] in which batteries need to be designed to improve the wellness of the environment and to store energy with a safe, efficient, and convenient method. The Aqueous Rechargeable Lithium-ion Battery (ARLB) This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.