Abstract: A method for determining a rotational frequency of a positive displacement motor positioned in a downhole portion of a drill string, the method including: providing at least one measurement device for measuring a property of a part of the drill string; providing a processor for processing a signal output by the at least one measurement device; operating the positive displacement motor whilst the part of the drill string is in a non-driven state; receiving the signal at the processor; determining, using the processor, a frequency spectrum of the signal; and determining the rotational frequency of the positive displacement motor by: identifying a peak in the frequency spectrum in a pre-determined frequency range associated with an expected rotational frequency of the positive displacement motor; and/or identifying a peak in the frequency spectrum having a pre-determined peak width associated with an expected rotational frequency of the positive displacement motor.

Abstract: A rendering process and system that may be used to composite virtual objects in panoramic video to provide a virtual reality and augmented reality experience. The process includes receiving low dynamic range (LDR) video data, e.g. 360° video; generating radiance maps, such as diffuse and specular maps, from the LDR data; inverse tone mapping the LDR data of the maps to generate high dynamic range (HDR) data for the maps; and receiving at least one virtual object and applying image based lighting (IBL) to the virtual object using the HDR data of the maps. A perceptually based threshold is also applied to radiance maps to detect prominent pixels, and using the prominent pixels as salient lights for image based shadowing (IBS) associated the virtual object. Objects are composited 360° video in real time using IBL and IBS without precomputation allowing user interaction with the objects.

Abstract: An apparatus and method for controlling a drilling system in a manner that reduces stick-slip by receiving a desired rotation speed v0 of the drive system to rotate the drillstring, receiving property measurements of the drilling system, and deriving therefrom a rotation speed vup of upgoing rotational waves of the drillstring associated with upgoing rotational energy in the drillstring. An actual rotation speed v of the drive system to rotate the drillstring is determined by representing downgoing energy in the drillstring as a mathematical expression containing a sum of downgoing rotational energy produced by the drive system and downgoing rotational energy caused by the upgoing rotational waves that are reflected downwardly at an upper end of the drillstring, and then optimizing the mathematical expression, which is then used for controlling the drive system to rotate the drillstring at v.

Abstract: Apparatus and methods for optimizing a stick-slip algorithm for controlling a driver of a drill string. A method may include commencing operation of a control system for controlling the driver. The control system may have a processor and a memory storing a computer program code, which may include the stick-slip algorithm. The operating control system may receive a plurality of different numerical parameters, and for each of the different numerical parameters, incorporate the numerical parameter into the stick-slip algorithm and execute the stick-slip algorithm to determine a control command that causes the driver to rotate the drill string to perform drilling operations while reducing amplitude of rotational waves travelling along the drill string.

Abstract: Methods and apparatus pertaining to scaling of the proportional gain and the integral gain in PI controllers of an autodriller based on drilling context. For example, a proportional gain and an integral gain are each determined for utilization by a PI controller of an autodriller controlling operation of equipment to be utilized for a drilling operation to drill a borehole into a subterranean formation. During the drilling operation, the integral gain is updated in real-time utilizing current values of drilling parameters that change with respect to time.

Abstract: Apparatus and methods automate selection of patient interface(s) according to their size, such as with processing in a processor(s) or in a server(s). Image data captured by an image sensor may be received. The captured image data may contain facial feature(s) of an intended user of the patient interface. The facial features may be captured in association with a predetermined reference feature of known dimension(s). The user's facial feature(s) and the reference feature may be detected in the captured image data. Image pixel data of the image may be processed to measure an aspect of the detected facial feature(s) based on the reference feature. A patient interface size may be detected from standard patient interface sizes based on a comparison between the measured aspect of the facial feature(s) and a data record relating sizing information of the standard patient interface sizes and the measured aspect of the facial feature(s).

Abstract: A system and method for operating a mud motor in a wellbore. The method includes running the mud motor into the wellbore. A threshold rate of a pressure increase over time is selected. A rate of a pressure increase over time is measured across the mud motor in the wellbore. A flow rate of a fluid being pumped into the wellbore is varied when the measured rate is greater than or equal to the threshold rate.

Abstract: Boron nitride nanotube (BNNT)-magnesium (Mg) alloy composites and methods of fabricating the same are provided. The BNNT-Mg alloy composites can have a sandwich structure and can be fabricated by high-pressure spark plasma sintering. A mat of BNNTs can be sputter-coated with Mg, and then sandwiched between Mg alloy particles, followed by a sintering step. The BNNTs can include a hexagonal boron nitride phase.

Abstract: Methods and apparatus for controlling drill string rotation. The apparatus may be a control system for controlling a driver operable to rotate a drill string to form a wellbore extending into a subterranean formation. The control system may include a first controller operable to control rotation of the driver and a second controller communicatively connected with the first controller.

Abstract: A method for changing a set point of a system where period of a dominant resonance of the system is determined, a change profile for the set point change is processed; a time period for the set point change based on the period of the dominant resonance in order to minimize excitation of the dominant resonance is also processed; and the set point change is actioned according to the processed change profile and the time period.

Abstract: An apparatus and method for controlling a drilling system in a manner that reduces stick-slip by receiving a desired rotation speed v0 of the drive system to rotate the drillstring, receiving property measurements of the drilling system, and deriving therefrom a rotation speed vup of upgoing rotational waves of the drillstring associated with upgoing rotational energy in the drillstring. An actual rotation speed v of the drive system to rotate the drillstring is determined by representing downgoing energy in the drillstring as a mathematical expression containing a sum of downgoing rotational energy produced by the drive system and downgoing rotational energy caused by the upgoing rotational waves that are reflected downwardly at an upper end of the drillstring, and then optimizing the mathematical expression, which is then used for controlling the drive system to rotate the drillstring at v.

Abstract: A method for detecting an influx and/or loss of circulation in a wellbore, comprising measuring a condition in the wellbore using a downhole sensor; determining that a positive displacement pump is shut off or turned on; predicting pit volume and/or gas concentration at a plurality of time points after the positive displacement pump is shut off or turned on using the measured condition in the wellbore prior to the positive displacement pump is shut off or turned on, wherein the measured condition correlates with the pit volume and/or gas concentration; measuring pit volume and/or gas concentration at the plurality of time points; comparing the predicted and the measured pit volumes and/or gas concentrations at the plurality of time points; and producing a warning signal if the difference between the predicted and the measured pit volumes and/or gas concentrations is greater than a pre determined value.

Abstract: An electronic device and a plurality of electronic devices can provide for database management systems and related methods. The database management system can provide a secure, verifiable record of saved information. The database management system can prevent post-fact tampering of the verified record, and can provide for access to the verified record.

Abstract: Methods and apparatus for controlling drill string rotation. The apparatus may be a control system for controlling a driver operable to rotate a drill string to form a wellbore extending into a subterranean formation. The control system may include a first controller operable to control rotation of the driver and a second controller communicatively connected with the first controller. During the drilling operations the first and/or second controller may be operable to generate a rotational speed command based on status information indicative of operational status of the drill string, and thereby cause the driver to rotate the drill string based on the rotational speed command.

Abstract: A social networking system determines common location information included in a set of posts between a set of users. Using the determined common location information, the social networking system generates a message interface for grouping a set of messages into a conversation thread. For example, the messages may be grouped into a conversation thread based on common location information in the messages and being associated with participants sharing a social relationship. When a group conversation is created, the social networking system presents a message interface containing the conversation thread to one or more participants of the thread. The social networking system adds the set of messages to the conversation thread based on social information about the social relationships among the participants of the conversation thread. The social networking system then presents the message interface for display to one or more of the participants.

Abstract: A method of manufacturing a patient interface for sealed delivery of a flow of air at a continuously positive pressure with respect to ambient air pressure to an entrance to the patient's airways includes collecting anthropometric data of a patient's face. Anticipated considerations are identified from the collected anthropometric data during use of the patient interface. The collected anthropometric data is processed to provide a transformed data set based on the anticipated considerations, the transformed data set corresponding to at least one customised patient interface component. At least one patient interface component is modeled based on the transformed data set.

Abstract: A pressure sensing retractor device and method is provided for measuring orbital compartment pressure of an eye. The device uses nested claw-like retractors where the inner claw retractor is capable of pulling an eyelid of the eye of a patient, and the outer claw retractor is capable of sensing the orbital compartment pressure of the eye. The pressure sensing retractor outputs the force sensor signal as a continuous signal of the orbital compartment pressure of the eye. Embodiments of the invention can be applied towards analysis of orbital compartment syndrome, retrobulbar hemorrhage (RBH), and canthotomy/cantholysis. Unlike applanation tonometry, retractor placement with the retractor provided herein requires no specialized training. Ease of use can help facilitate appropriate clinical decision, especially in environments without immediate access to ophthalmic consultation.

Abstract: A method for changing a set point of a system where period of a dominant resonance of the system is determined, a change profile for the set point change is processed; a time period for the set point change based on the period of the dominant resonance in order to minimize excitation of the dominant resonance is also processed; and the set point change is actioned according to the processed change profile and the time period.

Abstract: A method of manufacturing a patient interface for sealed delivery of a flow of air at a continuously positive pressure with respect to ambient air pressure to an entrance to the patient's airways includes collecting anthropometric data of a patient's face. Anticipated considerations are identified from the collected anthropometric data during use of the patient interface. The collected anthropometric data is processed to provide a transformed data set based on the anticipated considerations, the transformed data set corresponding to at least one customised patient interface component. At least one patient interface component is modelled based on the transformed data set.

Abstract: A method and autodriller for drilling a wellbore with a drill rig by rotating a drillstring and a drill bit with a drill rig drive system; applying an initial weight of the drillstring on the drill rig WOB; measuring drill rig properties to derive an anticipated drill bit rotation speed; and changing the weight of the drillstring on the drill rig WOB so that a corresponding change to the downhole weight on the drill bit occurs approximately simultaneously with a change in the anticipated drill bit rotation speed.