No abstract

The thermal decomposition behaviors of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowutrzitane (TEX) were studied by using accelerating rate calorimetry to achieve the hazard assessment of TEX explosive, and the kinetic parameters were studied from the measured selfheating rate data by assuming a zero-order reaction. Moreover, the specific heat capacity date of TEX was obtained from differential scanning calorimetry. These results could be contributed to improve the safety in the reaction, transportation, and storage processes of TEX.Keywords TEX Á Thermal stability Á Accelerating rate calorimetry (ARC) Á Explosive Abbreviations UThermal inertia factor T 0 /°C Initial self-heat temperature T f /°C Final decomposition temperature DT ad /°C Adiabatic temperature rise m 0 /°C min -1 Initial temperature rise rate m m /°C min -1 Maximum temperature rise rate T m /°C Temperature of maximum temperature rise rate H m /min Time of maximum temperature rise rate E a /kJ mol -1

A reasonable width of the coal pillar is very important to the surrounding rock control of the gob-side roadway. An unreasonable width of the coal pillar will make the roadway to be located within the range of strong mining influence, leading to severe deformation of the roadway. Severe subsidence at the coal pillar side of the roof and serious coal pillar deformation are problems caused by strong dynamic pressure due to mining in the gob-side coal roadway. This paper studies the surrounding rock instability mechanism and rational coal pillar width of the gob-side coal roadway under the influence of intense dynamic pressure. The results show that: (1) Under the condition of large mining height, the roadway overburden is a hinged structure, and an unreasonable coal pillar width makes the gob-side coal roadway to be located below the main roof fracture line. The rotary movement of the key block of the main roof is the main reason for the roadway deformation. (2) According to the evolution law of stress field, displacement field and plastic zone of surrounding rock of roadway under different coal pillar widths during roadway driving and mining were studied, and it is concluded that a 6-m-width coal pillar is the most reasonable. (3) Based on the stress distribution and plasticizing range of surrounding rock in a narrow pillar roadway, the combined support scheme of "anchor cable + grouting + single prop" is proposed and applied to engineering practice. The practice results show that the roadway deformation is well controlled, and the safe mining of the working face is realized.

Although NTO is unquestionably acidic, its potential to corrode weaponry and associated reaction mechanisms remains puzzling. Here, ab initio molecular dynamics (AIMD) with explicit solvation and “slow-growth” sampling approaches are...

Due to their tense mining succession relationship, gob-side roadways may undergo significant deformation under multi-mining pressure. In this article, many methods, such as on-site research, a theoretical analysis, a numerical simulation and an industrial experiment, are used to research the mechanism of asymmetric floor heave in a gob-side coal roadway affected by mining pressure during the mining of extra-thick coal seams. Our main research is as follows: (1) By monitoring the floor deformation in the roadway on site, it is concluded that the roadway floor shows asymmetry, indicating that the floor displacement near the coal pillar side is relatively large. (2) Based on a lateral overburden structure model of the roadway, the calculation formulas of the horizontal vertical stress caused by the roadway excavation and the excavation of the upper working face are derived separately, and the vertical stress coupling curves on both sides of the roadway during the mining of the upper working face are obtained through a numerical simulation. It is concluded that the cause of the asymmetric floor heave in the roadway is an uneven distribution of vertical stress. (3) The numerical simulation shows a symmetrical distribution of the floor displacement curve during the roadway excavation with a max. displacement of 49.5 mm. The floor displacement curve during the mining of the upper working face is asymmetric with a max. displacement of 873 mm at a distance of 1 m from the central axis near the coal pillar side. The range of the plastic zone in the roadway gradually expands with the mining of the upper working face, and the maximum depth of floor failure is 5.5 m. (4) According to the cooperative control principle of “roof + two sides + floor”, an asymmetric floor heave joint control scheme of “floor leveling + anchor cable support + concrete hardening” is proposed. The floor deformation monitoring results indicate that the max. floor heave at the measurement point near the coal pillar in the roadway is 167 mm, and the floor heave is effectively controlled.