Abstract: A database stores a document as a plurality of encrypted records, where each record is indicative of an incremental change to the state of the document, and encrypted using a document key. The document key is stored with encryption decryptable using a group key, and the group key is stored with encryption decryptable using a first access key. In response to a request to rotate from the first access key to a second access key, the database decrypts the group key using the first access key, a stores a group key re-encrypted with the second access key.

Abstract: The present disclosure is directed to a method for responding to a friction coefficient signal of a pitch bearing of a pitch drive mechanism of a wind turbine and/or for controlling the pitch drive mechanism(s) and/or a bank of ultracapacitors. The method and system include: accessing high-frequency measurement data of the at least one pitch bearing; estimating, via a torque balance model implemented by a controller, a frictional torque of the at least one pitch bearing based, at least in part, on the high-frequency measurement data; estimating, via the controller, a friction coefficient signal of the at least one pitch bearing based, at least in part, on the frictional torque; comparing the friction coefficient signal with a friction threshold; determining whether the friction coefficient signal deviates from the friction threshold based, at least in part, on the comparison; and, if so, acting.

Abstract: The present disclosure is directed to a method for responding to a friction coefficient signal of a pitch bearing of a pitch drive mechanism of a wind turbine and/or for controlling the pitch drive mechanism(s) and/or a bank of ultracapacitors. The method and system include: accessing high-frequency measurement data of the at least one pitch bearing; estimating, via a torque balance model implemented by a controller, a frictional torque of the at least one pitch bearing based, at least in part, on the high-frequency measurement data; estimating, via the controller, a friction coefficient signal of the at least one pitch bearing based, at least in part, on the frictional torque; comparing the friction coefficient signal with a friction threshold; determining whether the friction coefficient signal deviates from the friction threshold based, at least in part, on the comparison; and, if so, acting.

Abstract: A controller for operating a rod pumping unit at a pump speed. The controller includes a processor configured to operate a pump piston of the rod pumping unit at a first speed. The processor is further configured to determine a pump fillage level for a pump stroke based on a position signal and a load signal. The processor is further configured to reduce the pump speed to a second speed based on the pump fillage level for the pump stroke.

Abstract: A controller for operating a prime mover of a rod pumping unit includes a processor configured to operate the prime mover over a first stroke and a second stroke. The controller is further configured to compute a first motor torque imbalance value for the first stroke and engage adjustment of a counter-balance. The controller is further configured to estimate a second motor torque imbalance value for the second stroke. The controller is further configured to disengage adjustment of the counter-balance during the second stroke upon the second motor torque imbalance value reaching a first imbalance range.

Abstract: A controller for operating a rod pumping unit at a pump speed. The controller includes a processor configured to operate a pump piston of the rod pumping unit at a first speed. The processor is further configured to determine a pump fillage level for a pump stroke based on a position signal and a load signal. The processor is further configured to reduce the pump speed to a second speed based on the pump fillage level for the pump stroke.

Abstract: A controller for operating a rod pumping unit includes a processor configured to operate the rod pumping unit at a pumping profile speed. The processor is further configured to compute a first downhole dynamometer card from surface measurements at the rod pumping unit. The processor is further configured to compute a second downhole dynamometer card from the surface measurements. The processor is further configured to validate at least one of the first downhole dynamometer card and the second downhole dynamometer card based on a rod pumping unit condition.

Abstract: A controller for operating a prime mover of a rod pumping unit includes a processor configured to operate the prime mover over a first stroke and a second stroke. The controller is further configured to compute a first motor torque imbalance value for the first stroke and engage adjustment of a counter-balance. The controller is further configured to estimate a second motor torque imbalance value for the second stroke. The controller is further configured to disengage adjustment of the counter-balance during the second stroke upon the second motor torque imbalance value reaching a first imbalance range.

Abstract: A controller for operating a rod pumping unit at a pump speed. The controller includes a processor configured to operate a pump piston of the rod pumping unit at a first speed. The processor is further configured to determine a pump fillage level for a pump stroke based on a position signal and a load signal. The processor is further configured to reduce the pump speed to a second speed based on the pump fillage level for the pump stroke.

Abstract: A controller for operating a rod pumping unit includes a processor configured to operate the rod pumping unit at a pumping profile speed. The processor is further configured to compute a first downhole dynamometer card from surface measurements at the rod pumping unit. The processor is further configured to compute a second downhole dynamometer card from the surface measurements. The processor is further configured to validate at least one of the first downhole dynamometer card and the second downhole dynamometer card based on a rod pumping unit condition.

Abstract: A controller for operating a rod pumping unit at a pump speed. The controller includes a processor configured to operate a pump piston of the rod pumping unit at a first speed. The processor is further configured to determine a pump fillage level for a pump stroke based on a position signal and a load signal. The processor is further configured to reduce the pump speed to a second speed based on the pump fillage level for the pump stroke.

Abstract: A pressure relief device which is responsive to physical change in the end of a pressure vessel is formed by coining the end of the vessel. The device is self-regulating because the activation point automatically varies with vessel wall thickness.

Abstract: Apparatus for cutting and notching beams to predetermined specification comprising spaced parallel loading and discharge stations for receiving and discharging beams to be treated, transfer jaws operable to seize a beam at the receiving station and move it therefrom to the discharge station in a direction at right angles to its length, operating instrumentalities for performing one or more cutting operations on the beams at different places longitudinally thereof, trolleys supporting the operating instrumentalities intermediate the loading and discharge station at a level above the path of travel of the beams from the loading station to the discharge station such that the transfer jaws move the beams into engagement with all of the operating instrumentalities as they move the beams from the loading station to the discharge station and drive means for effecting reciprocation of the transfer jaws and operating instrumentalities.

Abstract: Apparatus for surface cutting logs to provide a finished surface corresponding to the natural surface contour of the log or to impart a predetermined distinctive surface contour thereto and a method of effecting such surface contouring; said apparatus comprising log guiding and feeding means for moving a log planed at diametrically opposite sides to have spaced parallel top and bottom surfaces and diametrically opposed debarked side surfaces or a log planed on all four sides so as to have spaced parallel top and bottom surfaces and spaced parallel side surfaces, cutting instrumentalities located at longitudinally spaced intervals along the path of movement of the log at different peripheral positions which collectively remove material from the side surfaces and guides associated with the cutting instrumentalities operable to control movement of the cutting instrumentalities in accordance with deviations in the surface of the log or according to a predetermined programmed pattern.