The possibility of using finite atomic functions of Kravchenko-Rvachev for description of the laws of distribution of the refractive index of the troposphere,the intensity of the scattering from the sea,seasonal behav...The possibility of using finite atomic functions of Kravchenko-Rvachev for description of the laws of distribution of the refractive index of the troposphere,the intensity of the scattering from the sea,seasonal behavior unit radar cross section(RCS)of land areas with vegetation covering,as well as the spectrum of electromagnetic spikes of lithospheric origin is considered.展开更多
Mercury concentration in water, sediments and two aquatic plants were measured in the Tigris River for the period in 2013 Hg concentrations in water between 0.18-0.74 μg/g, however, in sediments ranged between 0.66-0...Mercury concentration in water, sediments and two aquatic plants were measured in the Tigris River for the period in 2013 Hg concentrations in water between 0.18-0.74 μg/g, however, in sediments ranged between 0.66-0.73 lag/g. The concentrations of accumulated mercury in aquatic plants ranged in Ceratophyllum demersum and Phragmitus australis were 0.035-0.022, 0.028-0.023 μg/g, respectively. The concentration bioconcentration factor B.C.F range between 0.331-0.209 μg/g and B.S.F 0.043-0.011 μg/g. These results indicate the ability of the aquatic plants of Tigris River to accumulate elements in their tissues more than water consequently, mercury concentrations in the food chain path way could cause health problems on public health by transfer through aquatic organisms to human. The studied plants could be considered as bioindicator for elements flow to the river from natural and anthropogenic sources. The study showed there is an increase in the concentration of this element in the Tigris River and due to the low rate of discharge of river water, which leads to high concentrations of ions dissolved and effect divorced industrial waste and sewage and irrigation water, especially in the area of Zafaraniyah a result of the large number of events industrialized as well as the impact of the Diyala River on the River Tigris.展开更多
An armored face conveyor(AFC) is a key piece of equipment for a fully mechanized long-wall mining system and is currently the only means for transporting bulk material in hard coal mines. To date, the AFC power train ...An armored face conveyor(AFC) is a key piece of equipment for a fully mechanized long-wall mining system and is currently the only means for transporting bulk material in hard coal mines. To date, the AFC power train design has mainly been based on heuristics obtained via experience, coupled with simple calculations, which cannot take the dynamic behaviors and coupling effects of the components into consideration. Therefore, model-based and simulation-driven design is preferred. In this paper, a new design and analysis methodology for an AFC power train is presented to achieve the optimal dynamic characteristics and transmission performance. A preliminary design procedure for a power train is first introduced. Then, a system-level hydro-mechatronic model of the power train is built to evaluate and optimize the preliminary scheme. Sub-models, including those for the motors, fluid couplers, gearboxes, and chain, are obtained according to their individual disciplines and assembled to form the system-level model. The chain sub-system is discretized into multiple finite elements. Governing equations are established for each element based on the Newton Euler approach and assembled according to the topological structure of the chain system. In order to make the new approach applicable for engineers, a design and analysis software is developed, with a graphical user interface that involves the whole design process. MATLAB/SIMULINK is used as the computational engine, and Visual C++ is adopted to develop the interactive software framework. Simulations for the SGZ1000/2000 type AFC are provided as an illustrative case study to validate the effectiveness and practicality of the model and software package.展开更多
文摘The possibility of using finite atomic functions of Kravchenko-Rvachev for description of the laws of distribution of the refractive index of the troposphere,the intensity of the scattering from the sea,seasonal behavior unit radar cross section(RCS)of land areas with vegetation covering,as well as the spectrum of electromagnetic spikes of lithospheric origin is considered.
文摘Mercury concentration in water, sediments and two aquatic plants were measured in the Tigris River for the period in 2013 Hg concentrations in water between 0.18-0.74 μg/g, however, in sediments ranged between 0.66-0.73 lag/g. The concentrations of accumulated mercury in aquatic plants ranged in Ceratophyllum demersum and Phragmitus australis were 0.035-0.022, 0.028-0.023 μg/g, respectively. The concentration bioconcentration factor B.C.F range between 0.331-0.209 μg/g and B.S.F 0.043-0.011 μg/g. These results indicate the ability of the aquatic plants of Tigris River to accumulate elements in their tissues more than water consequently, mercury concentrations in the food chain path way could cause health problems on public health by transfer through aquatic organisms to human. The studied plants could be considered as bioindicator for elements flow to the river from natural and anthropogenic sources. The study showed there is an increase in the concentration of this element in the Tigris River and due to the low rate of discharge of river water, which leads to high concentrations of ions dissolved and effect divorced industrial waste and sewage and irrigation water, especially in the area of Zafaraniyah a result of the large number of events industrialized as well as the impact of the Diyala River on the River Tigris.
基金supported by the National Natural Science Foundation of China(Grant No.51375330)the Leading Talent Project of Guangdong Province
文摘An armored face conveyor(AFC) is a key piece of equipment for a fully mechanized long-wall mining system and is currently the only means for transporting bulk material in hard coal mines. To date, the AFC power train design has mainly been based on heuristics obtained via experience, coupled with simple calculations, which cannot take the dynamic behaviors and coupling effects of the components into consideration. Therefore, model-based and simulation-driven design is preferred. In this paper, a new design and analysis methodology for an AFC power train is presented to achieve the optimal dynamic characteristics and transmission performance. A preliminary design procedure for a power train is first introduced. Then, a system-level hydro-mechatronic model of the power train is built to evaluate and optimize the preliminary scheme. Sub-models, including those for the motors, fluid couplers, gearboxes, and chain, are obtained according to their individual disciplines and assembled to form the system-level model. The chain sub-system is discretized into multiple finite elements. Governing equations are established for each element based on the Newton Euler approach and assembled according to the topological structure of the chain system. In order to make the new approach applicable for engineers, a design and analysis software is developed, with a graphical user interface that involves the whole design process. MATLAB/SIMULINK is used as the computational engine, and Visual C++ is adopted to develop the interactive software framework. Simulations for the SGZ1000/2000 type AFC are provided as an illustrative case study to validate the effectiveness and practicality of the model and software package.
