To study the law of gas dilatation energy release of rock cross-cut coal uncovering face, according to the analysis of the physical parameters distribution features of coal and rock mass in front of crosscut face,the ...To study the law of gas dilatation energy release of rock cross-cut coal uncovering face, according to the analysis of the physical parameters distribution features of coal and rock mass in front of crosscut face,the equations of elastic potential of coal and gas dilatation energy theory were set up to process a contrast calculation of the sizes of two kinds of energy. The results show that gas dilatation energy is the uppermost energy source causing outburst occurrence. Furthermore, the mathematical model of spherical flow field gas dilatation energy release was established and MATLAB software was applied to make a numerical calculation analysis on the law of gas dilatation energy release. The results indicate that the gas dilatation energy is closely related to gas parameters and its energy index does reflect the possibility of coal seam outburst.展开更多
Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional part...Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional particle method is employed, which was successfully used for flow simulations of impulse-type and open cross-flow-type nano-hydraulic turbines in the authors＇ previous works. When the clearance Hc is smaller than a critical value, the simulated turbine performance decreases with decreasing Hc, in good agreement with the experiment. The simulations make it clear that such a reduction of turbine performance is attributable to an increase in the circumferential component of the water velocity at the rotor outlet. The simulations also demonstrate that the effect of the tip speed ratio of the rotor on the relation between Hc and turbine performance can be analyzed.展开更多
With the development of the offshore deep water oil industry many researchers are focusing on the vortex-induced vibrations （VIV） of deep risers. In the present work, Reynolds-averaged Navier-Stokes （RANS） equatio...With the development of the offshore deep water oil industry many researchers are focusing on the vortex-induced vibrations （VIV） of deep risers. In the present work, Reynolds-averaged Navier-Stokes （RANS） equations were combined with the SST κ-ω turbulent model to simulate the stream-wise and transverse motion of an elastically mounted cylinder with a low mass-ratio, a natural frequency ratio of fx/fy = 1 and an Re number between 5 300 and 32 000, The four-order Runge-Kutta method was applied to solve the oscillating equation of the cylinder. The relationship between reduced velocity and parameters of the cylinder, including the lift coefficient, the drag coefficient, displacement and the vortex structure were then compared with recent experimental results and discussed in detail. The present numerical simulation reproduced effects have been observed in experiments, such as the lock-in phenomenon, the hysteretic phenomenon and beating behavior.展开更多
In the agricultural industry, the importance of transportation costs increases considerably as fuel and labor costs climb. Logistic cooperation is an important strategic alternative to reduce transportation costs and ...In the agricultural industry, the importance of transportation costs increases considerably as fuel and labor costs climb. Logistic cooperation is an important strategic alternative to reduce transportation costs and increase efficiencies. Georgia＇s ornamental industry is characterized by producers that share clients, routes and origins; however, each producer has an independent transportation system. This paper analyses a case study to determine if a transportation alliance, through a horizontal cooperation and routing junction among ornamental producers in Georgia, would reduce shipping costs, increase distribution efficiencies and reduce carbon dioxide emissions. Routing and cost analysis were conducted followed by a sensitivity analysis for each constraint. Results showed that with the use of the GIS ArcLogistics 9.3 software, transportation alliances in the ornamental industry are profitable in terms of transport efficiencies and internal and external costs. Total cost savings per shipping cycle ranged from 1.0% to 13.2%, miles driven savings ranged from 1.1% to 13.6%, total number of trucks required savings ranged from 2.5% to 10% and driving hours savings ranged from 1.0% to 18.4%. CO2 emission reductions were also achieved ranging from 1.2% to 8.4% per shipping cycle.展开更多
We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entan...We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entangled optical states.Indeed,the decoherence effect is exploited positively here to generate such kind of quantum channels.Next,the amplitude damping and the entanglement amount of these produced channels are enhanced thereafter by a probabilistic quasi amplification process using again a 50 : 50 beam splitter.展开更多
文摘To study the law of gas dilatation energy release of rock cross-cut coal uncovering face, according to the analysis of the physical parameters distribution features of coal and rock mass in front of crosscut face,the equations of elastic potential of coal and gas dilatation energy theory were set up to process a contrast calculation of the sizes of two kinds of energy. The results show that gas dilatation energy is the uppermost energy source causing outburst occurrence. Furthermore, the mathematical model of spherical flow field gas dilatation energy release was established and MATLAB software was applied to make a numerical calculation analysis on the law of gas dilatation energy release. The results indicate that the gas dilatation energy is closely related to gas parameters and its energy index does reflect the possibility of coal seam outburst.
文摘Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional particle method is employed, which was successfully used for flow simulations of impulse-type and open cross-flow-type nano-hydraulic turbines in the authors＇ previous works. When the clearance Hc is smaller than a critical value, the simulated turbine performance decreases with decreasing Hc, in good agreement with the experiment. The simulations make it clear that such a reduction of turbine performance is attributable to an increase in the circumferential component of the water velocity at the rotor outlet. The simulations also demonstrate that the effect of the tip speed ratio of the rotor on the relation between Hc and turbine performance can be analyzed.
文摘With the development of the offshore deep water oil industry many researchers are focusing on the vortex-induced vibrations （VIV） of deep risers. In the present work, Reynolds-averaged Navier-Stokes （RANS） equations were combined with the SST κ-ω turbulent model to simulate the stream-wise and transverse motion of an elastically mounted cylinder with a low mass-ratio, a natural frequency ratio of fx/fy = 1 and an Re number between 5 300 and 32 000, The four-order Runge-Kutta method was applied to solve the oscillating equation of the cylinder. The relationship between reduced velocity and parameters of the cylinder, including the lift coefficient, the drag coefficient, displacement and the vortex structure were then compared with recent experimental results and discussed in detail. The present numerical simulation reproduced effects have been observed in experiments, such as the lock-in phenomenon, the hysteretic phenomenon and beating behavior.
文摘In the agricultural industry, the importance of transportation costs increases considerably as fuel and labor costs climb. Logistic cooperation is an important strategic alternative to reduce transportation costs and increase efficiencies. Georgia＇s ornamental industry is characterized by producers that share clients, routes and origins; however, each producer has an independent transportation system. This paper analyses a case study to determine if a transportation alliance, through a horizontal cooperation and routing junction among ornamental producers in Georgia, would reduce shipping costs, increase distribution efficiencies and reduce carbon dioxide emissions. Routing and cost analysis were conducted followed by a sensitivity analysis for each constraint. Results showed that with the use of the GIS ArcLogistics 9.3 software, transportation alliances in the ornamental industry are profitable in terms of transport efficiencies and internal and external costs. Total cost savings per shipping cycle ranged from 1.0% to 13.2%, miles driven savings ranged from 1.1% to 13.6%, total number of trucks required savings ranged from 2.5% to 10% and driving hours savings ranged from 1.0% to 18.4%. CO2 emission reductions were also achieved ranging from 1.2% to 8.4% per shipping cycle.
文摘We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entangled optical states.Indeed,the decoherence effect is exploited positively here to generate such kind of quantum channels.Next,the amplitude damping and the entanglement amount of these produced channels are enhanced thereafter by a probabilistic quasi amplification process using again a 50 : 50 beam splitter.
