Thermal loading of explosives--finite difference method with time step reduction.
The method of simulation of heat transfer during thermal loading of energetic materials is introduced. The combination of the simple finite difference method with a time step reduction enables the quick and precise calculation of ignition times. The results are in accordance with published model data. The method was also used to simulate heat transfer during the slow cookoff test and the result agrees very well with experimental data.
Dynamic characteristics and damage recognition of blast-induced ground vibration for natural gas transmission pipeline and its integrated systems
Abstract Natural gas pipeline network is a highly integrated network that moves natural gas throughout the continental and global services. Pipelines play a major role for the onshore and offshore gas transport, maintaining the record levels built up in recent years. However, once a rupture appears on a pipeline, the consequences of blast-induced incidents can pose a deadly threat in the vicinity of the failure location. Blast-induced ground vibration is the most significant impact that can seriously affect the surrounding parallel pipelines. In the present study, an experiment combined with a numerical investigation on the effect of blast-induced ground vibration of gas pipeline was undertaken. Dynamic characteristics such as peak vibration velocity, ground vibration acceleration, frequency response of blast-induced ground vibration were analyzed. Further, the modified prediction equations for blast-induced ground vibrational characteristics with distance were proposed. Ultimately, blast-induced displacement with the parallel pipeline was simulated, with a focus on risk vulnerability of gas pipeline. The main purpose of this paper is to facilitate a better understanding of the mechanical systems and dynamic characteristics governing the blast-induced ground vibration when the gas pipeline bursts, which is expected to be reliable for the safety spacing of buried integrated pipeline systems.
Phase relations in the MgMoO4Mg3V2O8 system and crystal structure of Mg2.54V1.08Mo0.92O8
Abstract The phase relationships in the pseudobinary MgMoOMg3V2O8 system have been determined by differential thermal analysis and X-ray diffraction analysis. The intermediate compound Mg2.5VMoO8 was found to exhibit a considerable solid solution Mg2.54V1.08Mo0.92O8 (−0.05 ≤ x ≤ 0.05) at 1100°C in air. Single crystals with composition of Mg2.54V1.08Mo0.92O8 were successfully grown from the MgVMo-Oxide flux, Mg2.54V1.08Mo0.92O8 crystallizes in the orthorhombic system, space group Pnma with a = 5.058(1) A , b = 10.307(3) A , c = 17.402(4) A , Z = 6 . The vanadium and molybdenum cations remain in their highest oxidation states and charge neutrality associated with the variation of the V Mo atomic ratio is balanced by an increase or decrease in the number of magnesium cations in the crystal.