A scroll compressor having an orbiting scroll and an Oldham ring is disclosed. According to various embodiments of the present invention, if an orbiting scroll and an Oldham ring are made from the same material, the orbiting scroll has a first key made from a material different therefrom to improve friction characteristics, wherein the first key is accommodated so as to be slidable along a slot formed at the Oldham ring. The first key can be press-fitted into and coupled to the orbiting scroll. Therefore, the first key is supported by the orbiting scroll without a reduction in size of the cross sectional area thereof, and thus the support stiffness of the first key can be reinforced.

Disclosed is a vertical axis wind turbine air concentration tower with reduced radar cross section. The air concentration tower has a polygonal outer perimeter, a pivot located at each vertex of the polygonal outer perimeter, and an inwardly-positioned rudder blade operatively connected at each pivot. Each inwardly positioned rudder blade has a first wind-neutral position, and is pivotable through a plurality of angles that adjust based on an incoming wind direction, such that the incoming wind is channeled to the vertical axis wind turbine, which is located approximately at a center area of the polygonal outer perimeter. A radar absorbent material is applied to the vertical axis wind turbine air concentration tower to reduce the radar cross section. The air concentration tower is designed to provide higher wind speed to the vertical axis wind turbine than the surrounding ambient air.

Disclosed is a vertical axis wind turbine air concentration tower with reduced radar cross section. The air concentration tower has a polygonal outer perimeter, a pivot located at each vertex of the polygonal outer perimeter, and an inwardly-positioned rudder blade operatively connected at each pivot. Each inwardly positioned rudder blade has a first wind-neutral position, and is pivotable through a plurality of angles that adjust based on an incoming wind direction, such that the incoming wind is channeled to the vertical axis wind turbine, which is located approximately at a center area of the polygonal outer perimeter. A radar absorbent material is applied to the vertical axis wind turbine air concentration tower to reduce the radar cross section. The air concentration tower is designed to provide higher wind speed to the vertical axis wind turbine than the surrounding ambient air.

An integral ring gear and torque arm for a wind turbine gearbox and method of manufacturing same includes forming the ring gear and the associated gear housing as a single part using the same material, e.g., using a casting process. Further, the ring gear defines an inner circumferential surface having a plurality of gear teeth. Thus, the method also includes applying a coating material to the gear teeth of the ring gear via an additive manufacturing process, such as cold spraying, so as to increase a hardness of gear teeth.

An integral ring gear and torque arm for a wind turbine gearbox and method of manufacturing same includes forming the ring gear and the associated gear housing as a single part using the same material, e.g., using a casting process. Further, the ring gear defines an inner circumferential surface having a plurality of gear teeth. Thus, the method also includes applying a coating material to the gear teeth of the ring gear via an additive manufacturing process, such as cold spraying, so as to increase a hardness of gear teeth.

A wind turbine blade for a wind turbine is a shell structure of a fiber-reinforced composite and comprises a root region and an airfoil region. The root region has a ring-shaped cross section and comprises a cylindrical insert 7 embedded in the fiber-reinforced polymer so as to substantially follow the circumference of the root region. The cylindrical insert is provided with a number of mutually spaced threaded bores 12, 15 in a first end 9 thereof being accessible from the outside.

A scroll compressor includes a fixed scroll, an orbiting scroll, a rotating shaft, an Oldham ring, and a plurality of first keys. The orbiting scroll is configured to engage the fixed scroll. The rotating shaft is eccentrically coupled to the orbiting scroll and configured to operate the orbiting scroll. The Oldham ring has a ring body that defines a plurality of slots. The plurality of first keys are coupled to the orbiting scroll and inserted to the plurality of slots, respectively. The plurality of first keys are configured to slide at the plurality of slots in a radial direction and include a material different from a material of the Oldham ring.