Abstract: Churn-aware training of a classifier which reduces the difference between predictions of two different models, such as a prior generation of a classification model and a subsequent generation. A second dataset of labelled data is scored on a prior generation of a classification model, wherein the prior generation was trained on a first dataset of labelled data. A subsequent generation of a classification model is trained with the second dataset of labelled data, wherein in training of the subsequent generation, weighting of at least some of the labelled data in the second dataset, such as labelled data threat yielded an incorrect classification, is adjusted based on the score of such labelled data in the prior generation.

Abstract: A turbine blade has a root portion, a platform and an aerofoil, the aerofoil is mounted on the platform and is formed by a pressure side wall and a suction side wall and has an outer surface, the pressure side wall and the suction side wall meet at a leading edge and a trailing edge, the aerofoil has an axial chord length, the suction side wall defines part of the radially outward surface of the aerofoil, the suction side wall defines an overhang, the overhang has a maximum overhang length that is between 5% and 20% of the axial chord length of the blade and is located between 5% and 50% of the suction surface length from the leading edge.

Abstract: A rotary steering apparatus for a drill string in which a bending section induces a bend in a portion of the bottom hole assembly of the drill string by using the rotation of the drive shaft that drives the drill bit during normal drilling, while operating at a reduced or zero drilling mud flow rate, to drive a reduction gear that rotates a nut or cam so as to place a tension tube into tension. The tension tube abuts a flexible housing and places the flexible housing in compression. The flexible housing has a local weakening formed in it that causes it to preferentially bend in a predetermined direction. Compression in the flexible housing causes the housing to bend, which bends a portion of the bottom hole assembly so as to alter the direction of drilling. Rotation of the drive shaft at reduced or zero mud flow rate also causes the drive shaft to drive rotation of a second reduction gear the output of which rotates the bent portion of the bottom hole assembly thereby altering its tool face angle.

Abstract: A rotary steering apparatus for a drill string in which a bending section induces a bend in a portion of the bottom hole assembly of the drill string by using the rotation of the drive shaft that drives the drill bit during normal drilling, while operating at a reduced or zero drilling mud flow rate, to drive a reduction gear that rotates a nut or cam so as to place a tension tube into tension. The tension tube abuts a flexible housing and places the flexible housing in compression. The flexible housing has a local weakening formed in it that causes it to preferentially bend in a predetermined direction. Compression in the flexible housing causes the housing to bend, which bends a portion of the bottom hole assembly so as to alter the direction of drilling. Rotation of the drive shaft at reduced or zero mud flow rate also causes the drive shaft to drive rotation of a second reduction gear the output of which rotates the bent portion of the bottom hole assembly thereby altering its tool face angle.

Abstract: A turbine blade has a root portion, a platform and an aerofoil, the aerofoil is mounted on the platform and is formed by a pressure side wall and a suction side wall and has an outer surface, the pressure side wall and the suction side wall meet at a leading edge and a trailing edge, the aerofoil has an axial chord length, the suction side wall defines part of the radially outward surface of the aerofoil, the suction side wall defines art overhang, the overhang has a maximum overhang length that is between 5% and 20% of the axial chord length of the blade and is located between 5% and 50% of the suction surface length from the leading edge.

Abstract: A fluid actuated downhole tool for inducing movement of a downhole apparatus is described. The tool comprises a body for coupling to downhole apparatus, the body being adapted to accommodate now of fluid therethrough and including a flow-modifying arrangement for modifying the flow of fluid through the body. The flow-modifying arrangement is configurable in an inactive configuration and in an active configuration. The fluid activated tool is selectively operated from the surface by varying an operating condition which causes the flow through the tool to either bypass or flow through the flow-modifying arrangement to induce movement of the downhole apparatus.

Abstract: A fluid actuated downhole tool for inducing movement of a downhole apparatus is described. The tool comprises a body for coupling to downhole apparatus, the body being adapted to accommodate now of fluid therethrough and including a flow-modifying arrangement for modifying the flow of fluid through the body. The flow-modifying arrangement is configurable in an inactive configuration and in an active configuration. The fluid activated tool is selectively operated from the surface by varying an operating condition which causes the flow through the tool to either bypass or flow through the flow-modifying arrangement to induce movement of the downhole apparatus.

Abstract: A wire line operated shut-in tool for a tubing string of an oil or gas well has a locking mandrel for cooperation with a ported landing nipple disposed below a packer in the tubing string to lock the tool in position, and a mandrel core which passes through the locking mandrel and is axially movable relative thereto, the core having a lower portion which is surrounded by the locking mandrel and is caused to rotate by the engagement of pins projecting inwardly from the locking mandrel with a jay slot assembly machined on the outer surface of the core when the core is moved axially. The arrangement of the jay slot assembly is such that by operating the wire line to move the core axially relative to the locking mandrel, the tool can be cycled between respective positions in which the well can be flowed, the reservoir shut-in, or the tool run out of the well.