A discrete-event system simulation and animation program was developed to enhance the efficiency of a truck-excavator operation and reduce the environmental impact of haulage in an open-cut coal mine with multiple-pit...A discrete-event system simulation and animation program was developed to enhance the efficiency of a truck-excavator operation and reduce the environmental impact of haulage in an open-cut coal mine with multiple-pit operations. In any mine, a key objective is to have sufficient equipment for production and not to have excess to where it becomes counterproductive. Due to the advent of responsible mining,environmental regulations, and eco-friendly practices, these factors must also be considered in the analysis. Simulation studies can be financially advantageous for both the optimization of existing mine operations and new development phases in a mine. This study is a new approach to use discrete-event system simulation for mine systems, in order to investigate and possibly reduce environmental impact considering mining haulage performance and production target. A hypothetical layout of a surface coal mine with two pit operations was used for the simulation and animation model. The simulation model includes the animation of the operation. Animation is helpful to enhance the benefit of a mine simulation model. GPSS/Hòand Proof Professionalòwere the software used for the investigation.展开更多
The passive flight of large numbers of mitospores ensures propagation and survival of many fungal species. Moreover, many fungi have a surplus DNA context which allows for easier manipulation and tampering, especially...The passive flight of large numbers of mitospores ensures propagation and survival of many fungal species. Moreover, many fungi have a surplus DNA context which allows for easier manipulation and tampering, especially when inserting eukaryotic genes and translation systems. These facts taken together suggest a high prominence of the sporogonic airborne fungi in biosecurity/biodefence priority lists, but due to the low virulence and mortality of the fungal pathogens, they do not figure high, or, sometimes, not at all. The disruptive effect of biosecurity fungal threats is important per se and genetic manipulations are to further it. Novel, long range and high-persistence sampling methods, using robotics and unmanned systems already fielded in other applications may extend surveillance and responsive sampling. Effects-based, proteomic approaches may provide a solution for deliberate incidents, while polyphasic taxonomy may resolve spontaneous incidents and assist medical diagnosis, but in the biosecurity context, where mass collection and processing of samples and speed in producing robust results are vital, complex approaches might be proved more of a hindrance than an asset.展开更多
Harmful algal blooms, which frequently occur in different tributaries, have become a serious water quality problem of the Three Gorges Reservoir (TGR) since its initial filling. A three-year monitoring campaign from 2...Harmful algal blooms, which frequently occur in different tributaries, have become a serious water quality problem of the Three Gorges Reservoir (TGR) since its initial filling. A three-year monitoring campaign from 2008 to 2010 was conducted to identify the controlling factors of algal blooms and effective preventive measures. The following results were obtained: 1) Layered and bidirectional currents, called intrusive density currents, dominate the tributary bays of the TGR year round; 2) continuously increasing water level can make the intruding density current shift from the middle to the surface, and surface intrusive water can reduce the surface water temperature and break the stable stratification of the tributary; 3) the appearing or fading away of algal blooms is closely associated with fluctuations in the TGR water level. Thus, the water level fluctuation patterns of different "tide-types" may prevent the occurrence of algal blooms in the spring and summer, and the "stair-type" tides may control autumn blooms during the impounding period. These methods were feasible and effective throughout the actual TGR's operation in 2009 2011. These patterns formed an eco-environmentally friendly operation (EEFO) to mitigate algal blooms. As an in situ treatment with easier operation and less negative impact and loss, compared with chemical and filter-feeding fish methods, the EEFO is currently considered as the most feasible remedial measure to remit the eco-environmental problems at the Three Gorges Dam (TGD).展开更多
Bees are the main contributors of pollination and it is predicted that disruption of pollination causes some serious problems in economics, agriculture and ecology. It has been reported that honeybee colony collapse h...Bees are the main contributors of pollination and it is predicted that disruption of pollination causes some serious problems in economics, agriculture and ecology. It has been reported that honeybee colony collapse has increased dramatically for some time in different parts of the world. In order to investigate the causes of colony collapse, we establish a fractional multi-order honeybee colony population model. Two different models with Caputo and Caputo-Fabrizio differentiation operators have been compared. We justify the existence and uniqueness of the solution. Stability analysis has been presented. We find the numerical values of the fractional order （p, q） so that the numerical results are close to the experimental findings more than the integer-order case.展开更多
文摘A discrete-event system simulation and animation program was developed to enhance the efficiency of a truck-excavator operation and reduce the environmental impact of haulage in an open-cut coal mine with multiple-pit operations. In any mine, a key objective is to have sufficient equipment for production and not to have excess to where it becomes counterproductive. Due to the advent of responsible mining,environmental regulations, and eco-friendly practices, these factors must also be considered in the analysis. Simulation studies can be financially advantageous for both the optimization of existing mine operations and new development phases in a mine. This study is a new approach to use discrete-event system simulation for mine systems, in order to investigate and possibly reduce environmental impact considering mining haulage performance and production target. A hypothetical layout of a surface coal mine with two pit operations was used for the simulation and animation model. The simulation model includes the animation of the operation. Animation is helpful to enhance the benefit of a mine simulation model. GPSS/Hòand Proof Professionalòwere the software used for the investigation.
文摘The passive flight of large numbers of mitospores ensures propagation and survival of many fungal species. Moreover, many fungi have a surplus DNA context which allows for easier manipulation and tampering, especially when inserting eukaryotic genes and translation systems. These facts taken together suggest a high prominence of the sporogonic airborne fungi in biosecurity/biodefence priority lists, but due to the low virulence and mortality of the fungal pathogens, they do not figure high, or, sometimes, not at all. The disruptive effect of biosecurity fungal threats is important per se and genetic manipulations are to further it. Novel, long range and high-persistence sampling methods, using robotics and unmanned systems already fielded in other applications may extend surveillance and responsive sampling. Effects-based, proteomic approaches may provide a solution for deliberate incidents, while polyphasic taxonomy may resolve spontaneous incidents and assist medical diagnosis, but in the biosecurity context, where mass collection and processing of samples and speed in producing robust results are vital, complex approaches might be proved more of a hindrance than an asset.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51179095, 51179205, 51009081 and 51209123)
文摘Harmful algal blooms, which frequently occur in different tributaries, have become a serious water quality problem of the Three Gorges Reservoir (TGR) since its initial filling. A three-year monitoring campaign from 2008 to 2010 was conducted to identify the controlling factors of algal blooms and effective preventive measures. The following results were obtained: 1) Layered and bidirectional currents, called intrusive density currents, dominate the tributary bays of the TGR year round; 2) continuously increasing water level can make the intruding density current shift from the middle to the surface, and surface intrusive water can reduce the surface water temperature and break the stable stratification of the tributary; 3) the appearing or fading away of algal blooms is closely associated with fluctuations in the TGR water level. Thus, the water level fluctuation patterns of different "tide-types" may prevent the occurrence of algal blooms in the spring and summer, and the "stair-type" tides may control autumn blooms during the impounding period. These methods were feasible and effective throughout the actual TGR's operation in 2009 2011. These patterns formed an eco-environmentally friendly operation (EEFO) to mitigate algal blooms. As an in situ treatment with easier operation and less negative impact and loss, compared with chemical and filter-feeding fish methods, the EEFO is currently considered as the most feasible remedial measure to remit the eco-environmental problems at the Three Gorges Dam (TGD).
文摘Bees are the main contributors of pollination and it is predicted that disruption of pollination causes some serious problems in economics, agriculture and ecology. It has been reported that honeybee colony collapse has increased dramatically for some time in different parts of the world. In order to investigate the causes of colony collapse, we establish a fractional multi-order honeybee colony population model. Two different models with Caputo and Caputo-Fabrizio differentiation operators have been compared. We justify the existence and uniqueness of the solution. Stability analysis has been presented. We find the numerical values of the fractional order （p, q） so that the numerical results are close to the experimental findings more than the integer-order case.
