Failure characteristics and control technology of surrounding rock during roadway passing collapse column.

The collapse column may result in failure of the surrounding rock during roadway excavation. It is of considerable importance to elucidate the failure characteristics and develop the corresponding control technologies for the surrounding rock. A discrete fracture mesh (DFN) and a strain-softening constitutive model are employed to simulate the properties of a collapse column.

Modelling of enhanced gas extraction in low permeability coal seam by controllable shock wave fracturing.

The controlled shock wave (CSW) fracturing is an effective method for enhancing permeability of coal seam to promote gas extraction. Based on Fick's law, Darcy's law, the ideal gas law and the Langmuir equation, a damage-seepage-deformation coupling mathematical model of CSW fracturing in coal seam combined with the maximum tensile stress and the Mohr-Coulomb criterion is established. This model is implemented into COMSOL Multiphysics to simulate the coal seam CSW fracturing and subsequent gas extraction.

A Long-Term Outcome of Symptomatic Middle Cerebral Artery Undergoing Intracranial Angioplasty or Stenting.

Objective: For symptomatic stenosis in the middle cerebral artery (MCA), intracranial angioplasty and stenting are frequently employed. However, limited data exist regarding their long-term impact. Our study demonstrates the long-term advantages in preventing ischemic events through a 5-year follow-up period.

Simulation on Harmful Gas Control by Balanced Pressure Ventilation in the Fully Mechanized Caving Face under Sealed Fire Area of Small Coal Mine.

The harmful gas in the sealed fire area of a small coal mine rushes into the mining face of the lower coal seam, which restricts the efficient promotion of the working face. In this paper, based on the evolution law of caving coal rock dilatation coefficient, the characteristics of the heterogeneous distribution of permeability and voidage in goaf were obtained, and the mathematical model of gas migration in goaf is constructed. The numerical solution of gas migration in goaf under the sealed fire area of a small coal mine was realized by using the Free and Porous Media Flow module and the Transport of Dilute Matter in Porous Media module in COMSOL Multiphysics, and the corresponding measure was proposed.

Influence of magma intrusion on coal geochemical characteristics: a case study of Tiefa Daxing coal mine.

Magma intrusion has an important influence on the physical and mechanical properties of coal and rock. In the area of magma intrusion, disasters such as gas outburst are prone to occur. Revealing its invasion law will be conducive to disaster management and energy development.

A Functional Electrolyte Containing P-Phenyl Diisothiocyanate (PDITC) Additive Achieves the Interphase Stability of High Nickel Cathode in a Wide Temperature Range.

The lithium-ion batteries (LIBs) with high nickel cathode have high specific energy, but as the nickel content in the cathode active material increases, batteries are suffering from temperature limitations, unstable performance, and transition metal dissolution during long cycling. In this work, a functional electrolyte with P-phenyl diisothiocyanate (PDITC) additive is developed to stabilize the performance of LiNi Co Mn O (NCM811)/graphite LIBs over a wide temperature range. Compared to the batteries without the additive, the capacity retention of the batteries with PDITC-containing electrolyte increases from 23 % to 74 % after 1400 cycles at 25 °C, and from 15 % to 85 % after 300 cycles at 45 °C.

Scale Effect on Uniaxial Compressive Properties of the Outburst-Prone Coal.

Coal is a naturally discontinuous, heterogeneous, and anisotropic brittle material. The uniaxial compressive strength of coals is significantly affected by the sample size-dominated microstructure of minerals and fractures. The scale effect of the mechanical properties of coal is a bridge connecting the mechanical parameters of laboratory-scale coal samples and engineering-scale coal.

Supporting optimization of thick seam roadway with top coal based on orthogonal matrix analysis.

Aiming at the problem of large deformation and difficulty in surrounding rock control of the top coal roadway in thick seam, theoretical analysis, theoretical analysis, numerical simulation, orthogonal matrix analysis and other methods were used to study the roof deformation and support parameter optimization of the top coal roadway in thick seam. Firstly, the structural model and roof mechanical model of the top coal roadway in thick seam were established, and the deformation coefficient T was defined based on the relationship between curvature radius and bending moment, maximum bending moment and ultimate tensile strength of beam. According to the ratio of deformation rate between T and beam to determine the roof deformation mode of top coal roadway, the discriminant conditions of roadway roof stability under two deformation conditions are obtained.

Bolt-Cable-Mesh Integrated Support Technology for Water Drenching Roadway in Thick Coal Seam.

Aiming at the problems of large deformation and difficult control of the mining roadway water drenching in a thick coal seam, the principle of double-arch zoning cooperative surrounding rock control is studied by using the combined method of theoretical analysis, numerical simulation, and industrial experiment. The water-rock interaction of the surrounding rock of water-drenching roadway is proposed, taking into account the damage to the mechanical parameters of the surrounding rock caused by soaking water. The water-mechanical-damage coupling model for surrounding rock of a coal seam roadway is constructed, and is numerically solved by the code development using the FISH language.

Numerical simulation of roadway deformation and failure under different degrees of dynamic disturbance.

Deformation and failure of the roadway surrounding rock under dynamic disturbance were explored, which is essential for the control of the surrounding rock. The impact of dynamic disturbance on the deformation and failure of the roadway surrounding rock was studied from a single factor perspective using numerical simulation software. The disturbance intensity, frequency, and time were determined to affect the deformation and plastic zone of the surrounding rock.

1,2,3,4-Tetrakis(2-cyanoethoxy)butane (TCEB)-Assisted Construction of Self-Repair Electrode Interface Films to Improve the Performance of 4.5 V Pouch LiCoO/Artificial Graphite Full Cells Operating at 45 °C.

1,2,3,4-Tetrakis(2-cyanoethoxy)butane (TCEB) is first evaluated as a functional electrolyte additive to increase the charge cutoff voltage and energy density of pouch LiCO (LCO)/artificial graphite (AG) lithium-ion batteries (LIBs) at a high temperature of 45 °C. The charge (0.7 C) and discharge (1 C) tests show that TCEB effectively improves the cycle stability of cells under a high charge cutoff voltage of 4.