The development and achievements of modern coal mining with stowing are discussed in this paper. The necessity of developing coal mining with stowing is briefly summarized and internal damage within the strata and ext...The development and achievements of modern coal mining with stowing are discussed in this paper. The necessity of developing coal mining with stowing is briefly summarized and internal damage within the strata and external damage on surface induced by longwall working with caving are discussed. Technological features of coal mining with pneumatic stowing in Germany, and fully mechanised coal mining with solid dense stowing in China, are discussed. In German hard coal mining stowing technologies are for technical, infrastructural and economical reasons not applicable. The discussion includes the stowing material transportation system, the stowing machine, and processes at the face. Progressiveness and application universality of China's fully mechanised coal mining with solid dense stowing are illustrated through practical examples with different conditions. Obviously, the fully mechanised coal mine with solid dense stowing can be improved by automaion systems. This paper discusses further developmental potential of the technology.展开更多
Drag reduction features in the transition regime of channel flow with fibre suspension were analyzed in terms of the linear stability theory. The modified stability equation was obtained based on the slender-body theo...Drag reduction features in the transition regime of channel flow with fibre suspension were analyzed in terms of the linear stability theory. The modified stability equation was obtained based on the slender-body theory and natural closure approximation. Results of the stability analysis show attenuating effects of fibre additives to the flow instability. For the cases leading to transition, drag reduction rate increases with the characteristic parameter H of fibres. The mechanism of drag reduction by fibres is revealed through the variation of velocity profile and the decrease of wall shear stress. The theoretical results are qualitatively consistent with some typical experiments.展开更多
The global demand for renewable and affordable feed-stocks,combined with the worldwide targets for reduc-ing carbon emissions,is the driving force behind a breakthrough in resource revolution and GreenTech innovations...The global demand for renewable and affordable feed-stocks,combined with the worldwide targets for reduc-ing carbon emissions,is the driving force behind a breakthrough in resource revolution and GreenTech innovations[1].Owing to the vast reserves and short growing cycle,utilizing lignocellulosic biomass as an alternative to petroleum and environmentally friendly feedstock to furnish bioenergy and biomaterials is key to building a more sustainable future.Lignocellulose mainly contains three biopolymers,i.e.,cellulose,hemicellulose and lignin.Over the centuries,utilization of lignocellu-lose has crossed its possible molecular scale ranging from 101 m,as the original matrix,to 10-10 m,as a mono-meric molecule.展开更多
文摘The development and achievements of modern coal mining with stowing are discussed in this paper. The necessity of developing coal mining with stowing is briefly summarized and internal damage within the strata and external damage on surface induced by longwall working with caving are discussed. Technological features of coal mining with pneumatic stowing in Germany, and fully mechanised coal mining with solid dense stowing in China, are discussed. In German hard coal mining stowing technologies are for technical, infrastructural and economical reasons not applicable. The discussion includes the stowing material transportation system, the stowing machine, and processes at the face. Progressiveness and application universality of China's fully mechanised coal mining with solid dense stowing are illustrated through practical examples with different conditions. Obviously, the fully mechanised coal mine with solid dense stowing can be improved by automaion systems. This paper discusses further developmental potential of the technology.
基金the National Natural Science Foundation of China (No. 10372090 and No. 10102017).
文摘Drag reduction features in the transition regime of channel flow with fibre suspension were analyzed in terms of the linear stability theory. The modified stability equation was obtained based on the slender-body theory and natural closure approximation. Results of the stability analysis show attenuating effects of fibre additives to the flow instability. For the cases leading to transition, drag reduction rate increases with the characteristic parameter H of fibres. The mechanism of drag reduction by fibres is revealed through the variation of velocity profile and the decrease of wall shear stress. The theoretical results are qualitatively consistent with some typical experiments.
文摘The global demand for renewable and affordable feed-stocks,combined with the worldwide targets for reduc-ing carbon emissions,is the driving force behind a breakthrough in resource revolution and GreenTech innovations[1].Owing to the vast reserves and short growing cycle,utilizing lignocellulosic biomass as an alternative to petroleum and environmentally friendly feedstock to furnish bioenergy and biomaterials is key to building a more sustainable future.Lignocellulose mainly contains three biopolymers,i.e.,cellulose,hemicellulose and lignin.Over the centuries,utilization of lignocellu-lose has crossed its possible molecular scale ranging from 101 m,as the original matrix,to 10-10 m,as a mono-meric molecule.
