MEDIASTINAL cavernous hemangioma is a kind of primary mediastinal mesenchymal tumor that occurs rarely in any age. It was first reported by Shennon in 1914. In this study we reported a case of mediastinal cavernous he...MEDIASTINAL cavernous hemangioma is a kind of primary mediastinal mesenchymal tumor that occurs rarely in any age. It was first reported by Shennon in 1914. In this study we reported a case of mediastinal cavernous hemangioma with abnormal vessel originating from left brachiocephalic vein.展开更多
In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic eff...In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic effect during its rotation at a high speed. A blade must have the maximum output and resist to aerodynamic loads distributed over its length, which are related to its geometrical characteristics and the speed of the wind. For that, the authors wrote the relations whom determine these loads according to the flow speed of the wind, then, the authors integrated them in the laws of structure mechanics to obtain the motion equations of the blade. This process was applied to a twisted blade with a length of 1.9 m, built out of pressed aluminum sheet with a profile of the type NACA; this profile gives the best aerodynamic output. This blade is an element of a three-bladed propeller for wind turbine of maximum power 5 kW. Finally, we visualized its deformations and then the authors checked its holding in service.展开更多
文摘MEDIASTINAL cavernous hemangioma is a kind of primary mediastinal mesenchymal tumor that occurs rarely in any age. It was first reported by Shennon in 1914. In this study we reported a case of mediastinal cavernous hemangioma with abnormal vessel originating from left brachiocephalic vein.
文摘In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic effect during its rotation at a high speed. A blade must have the maximum output and resist to aerodynamic loads distributed over its length, which are related to its geometrical characteristics and the speed of the wind. For that, the authors wrote the relations whom determine these loads according to the flow speed of the wind, then, the authors integrated them in the laws of structure mechanics to obtain the motion equations of the blade. This process was applied to a twisted blade with a length of 1.9 m, built out of pressed aluminum sheet with a profile of the type NACA; this profile gives the best aerodynamic output. This blade is an element of a three-bladed propeller for wind turbine of maximum power 5 kW. Finally, we visualized its deformations and then the authors checked its holding in service.
