THE worst year on record for rhino poaching in South Africa＇s history makes 2013 a dismal period for the endangered animal. Figures released by the South African Department of Environmental Affairs in January show th...THE worst year on record for rhino poaching in South Africa＇s history makes 2013 a dismal period for the endangered animal. Figures released by the South African Department of Environmental Affairs in January show that in 2013, just over 1,000 rhinos were illegally killed in South Africa - the equivalent of nearly three animals a day. The figure is more than 1.5 times the official figure of 668 rhinos killed for their horns in 2012. This brings South Africa＇s white rhino population ever closer to the tipping point, where deaths outnumber births and the population begins a serious decline.展开更多
A model roadway with a cross-sectional area of 80 mm 80 mm and a length of 100 m was used to estimate the overpressure, the temperature, the density, and the combustion rate during an explosion. Auto-ReaGas software w...A model roadway with a cross-sectional area of 80 mm 80 mm and a length of 100 m was used to estimate the overpressure, the temperature, the density, and the combustion rate during an explosion. Auto-ReaGas software was used for the calculations and the initial temperatures were 248, 268, 308, or 328 K. The methaneair mixture had a fuel concentration of 9.5% and the tunnel had a filling ratio of 10%. The results show that the safe distance necessary to avoid harm from the shock wave increases with increasing initial temperature. The distance where the peak overpressure begins to rise, and where the maximum value occurs, increases as the initial temperature increases. These are almost linear functions of the initial temperature. At locations before shock wave attenuation has occurred increasing the initial temperature linearly increases the maximum temperature at each point following along the tunnel. At the same time, the peak overpressure, the maximum density, and the maximum combustion rate decrease linearly. How-ever, after the shock wave has attenuated the attenuation extent of the peak overpressure decreases with an increase in initial temperature. The influence of the initial temperature on the explosion propagation depends on the combined effects of inhibiting and enhancing factors. The research results can provide a theoretical guidance for gas explosion disaster relief and treatment in underground coal mines.展开更多
文摘THE worst year on record for rhino poaching in South Africa＇s history makes 2013 a dismal period for the endangered animal. Figures released by the South African Department of Environmental Affairs in January show that in 2013, just over 1,000 rhinos were illegally killed in South Africa - the equivalent of nearly three animals a day. The figure is more than 1.5 times the official figure of 668 rhinos killed for their horns in 2012. This brings South Africa＇s white rhino population ever closer to the tipping point, where deaths outnumber births and the population begins a serious decline.
基金provided by the National Basic Research Program of China (No. 2011CB201205)the National Natural Science Foundation of Youth Science Foundation of China(No. 51004048)the Open Fund Program of the State Key Laboratory of Explosion Science and Technology (No. KFJJ10-19M)
文摘A model roadway with a cross-sectional area of 80 mm 80 mm and a length of 100 m was used to estimate the overpressure, the temperature, the density, and the combustion rate during an explosion. Auto-ReaGas software was used for the calculations and the initial temperatures were 248, 268, 308, or 328 K. The methaneair mixture had a fuel concentration of 9.5% and the tunnel had a filling ratio of 10%. The results show that the safe distance necessary to avoid harm from the shock wave increases with increasing initial temperature. The distance where the peak overpressure begins to rise, and where the maximum value occurs, increases as the initial temperature increases. These are almost linear functions of the initial temperature. At locations before shock wave attenuation has occurred increasing the initial temperature linearly increases the maximum temperature at each point following along the tunnel. At the same time, the peak overpressure, the maximum density, and the maximum combustion rate decrease linearly. How-ever, after the shock wave has attenuated the attenuation extent of the peak overpressure decreases with an increase in initial temperature. The influence of the initial temperature on the explosion propagation depends on the combined effects of inhibiting and enhancing factors. The research results can provide a theoretical guidance for gas explosion disaster relief and treatment in underground coal mines.
