Abstract: Described are methods, systems, and apparatus for reducing storage system polling when collecting and providing storage system state data. A plurality of poll requests for storage system state data is received. For each poll request of the plurality of poll requests, a poll request arrival time associated with the poll request is stored. A first poll is initiated to collect first storage system state data for a first poll request of the plurality of poll requests. A first poll start time associated with the first poll is stored. The first poll is completed, forming the first storage system state data. For each poll request of the plurality of poll requests, the first storage system state data is provided for the poll request provided that the poll request arrival time is before the first poll start time.

Abstract: Rectangular bleed ports (24) are circumferentially arranged. Each port has an average radius (r) greater than 30 percent of the port width (W) throughout the reactant surface of the upstream facing edge (30), thereby avoiding flow separation from the surface. A tangent point (36) at the junction of the reactant surface (36) and the inside surface of casing (12) is located a distance (x) upstream to blades (18) greater than 40 percent of the spacing between the blades. This reduces flow losses in the ports caused by blade upwash.

Abstract: A flow directing assembly 14 having an airfoil section or shape 28 of the type adapted for use in an axial flow gas turbine engine is disclosed. The cambered meanline MCL of the airfoil shape is formed of a front circular arc FA and a rear circular arc RA. A thickness distribution TD is applied to the meanline to form the convex suction surface 20 and the concave pressure surface 22. The airfoil section exhibits good aerodynamic performance as compared with an equivalent circular arc airfoil in a transonic flow field. A method for making the airfoil shape is disclosed. The method includes the steps of: forming a cambered meanline of two circular arcs; forming a thickness distribution about the conical chord line B.sub.t ; and applying thickness distribution to the cambered meanline such that a portion of the suction surface is stretched and a portion of the pressure surface is compressed.

Abstract: An airfoil tip seal structure for an axial flow rotary machine is disclosed. Various concepts relating to seal designs and their influence on tip sealing effectiveness are discussed. In accordance with the teaching contained herein, one seal geometry includes a circumferentially extending groove in the stator which circumscribes the tips of the blades of a corresponding rotor stage. Another seal geometry applicable to machines having cantilevered stator vanes includes a circumferentially extending groove in the rotor which circumscribes the tips of the vanes of a corresponding stator stage. The tips of the blades and the tips of the cantilevered stator vanes run over the corresponding groove in line on line relationship with the adjacent flow path wall at the design operating condition of the machine in which the seal structure is incorporated.