Abstract: A variable geometry turbine comprise a housing; a turbine wheel supported in the housing for rotation about a turbine axis; and an annular inlet passage upstream of said turbine wheel defined between respective inlet surfaces defined by an annular nozzle ring and a facing annular shroud. The nozzle ring and shroud are axially movable relative to one another to vary the size of the inlet passage; the nozzle ring having a circumferential array of inlet vanes extending across the inlet passage. The shroud covers the opening of a shroud cavity and defines a circumferential array of vane slots, each vane slot corresponding to an inlet vane, the vane slots and shroud cavity being configured to receive said inlet vanes to accommodate axial movement of the nozzle ring.

Abstract: Optical and electronic mechanisms for establishing bi-directional line-of-sight optical links between neighboring nodes to maintain continuous, error-free operation of a network are disclosed. The system provides operational status indication signals for operators and for data communication devices that are attached to nodes. The system provides decision-making logic systems to reconfigure the network path instantly and automatically to a hot standby path if an optical link between neighboring nodes becomes impaired. The system operates without a central controller and at the physical level of the Open System Interconnection reference model without modification to the Medium Access Control or Logical Link Control. Operation is transparent to all common network standards.