Abstract: Methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

Abstract: A coupler for coupling an RF connector to an ultrasound sensing element. The coupler includes a conductive coupler body with a first end and a second end. The first end includes a pad retaining recess with a compressible conductive pad positioned in and protruding from the pad retaining recess. The second end either includes an opening for receiving a male pin of a radio frequency (RF) connector or is shaped to be press-fitted into the female pin opening of an RF connector, to conductively connect the pin with the coupler body. A sensor connector is also disclosed.

Abstract: Disclosed is an equivalent acceleration method of creep loads based on a consistent failure mode. The equivalent acceleration method includes obtaining corresponding tensile strengths; obtaining corresponding creep rupture time; establishing rupture time law, minimum creep rate law and rupture strain law; calculating the value of parameter p in creep damage accumulation model; and dividing the failure mode consistency interval of creep load under variable temperature and variable load. The damage caused by the creep load in the failure mode consistency interval is calculated by using the multi-grade variable temperature and variable load creep nonlinear damage accumulation model, the damage is accelerated to the maximum creep load state in the failure mode consistency interval according to the principle of damage equivalence, and finally the equivalent acceleration of creep load is realized.

Abstract: Described are various embodiments of an ultrasonic structural health monitoring device, system and method. In one embodiment, an ultrasonic structural health monitoring device is described to monitor a structure. The device comprises a bottom electrode disposable on the structure; a piezoelectric medium disposed on the bottom electrode; a top electrode disposed on the piezoelectric medium; an acoustic insulation layer; and a connector to bring electrical excitation for the piezoelectric medium and to collect a generated electric response therefrom representative of structural health.

Abstract: A method of controlling a permanent magnet synchronous electric machine (PMSM) drive using a Deadbeat Predictive Current Control (DBPCC) scheme is provided. The method comprises: determining d-axis and q-axis stator current values (id, iq) representative of a measured PMSM current; determining d-axis and q-axis reference current values (id*, iq*); based on the stator current values (id, iq) and the reference current values (id*, iq*), determining d-axis and q-axis current correction values (Cd, Cq); determining corrected reference current values (id**, iq**) as a sum of the reference current values (id*, iq*) and the current correction values (Cd, Cq); and controlling the PMSM drive using the corrected reference current values (id**, iq**) as reference current inputs of the DBPCC scheme. A controller for performing the method; a system comprising the controller, a PMSM and associated power electronics; and a computer program for performing the method are also provided.

Abstract: A method of monitoring both liner wear and charge impact in an industrial mill uses a sensor mounted on an elongated element deployed through a shell into a liner of the mill. The elongated element wears at a same rate as the liner under conditions within the shell. Liner wear is related to a reduction in length of the elongated element as measured by travel time of an ultrasound wave, while location and strength of charge impact is related to change in amplitude of vibrations caused by the charge impact. Liner wear measurement can be improved by using shear ultrasound waves instead of conventional longitudinal ultrasound waves. A mill monitoring apparatus has a means for acquiring ultrasonic waves and audible sound waves using the same digitizer; a means for determining the angular position of the monitoring apparatus; and a means for supplying electric power to the apparatus.

Abstract: Disclosed is a method for predicting creep damage and deformation evolution behavior with time, which comprises the following steps: obtaining tensile strength ?b through high-temperature tensile test; obtaining the strain curve, minimum creep rate {dot over (?)}m and life tƒ through creep test; obtaining the threshold stress ?th at different temperatures; establishing the relationship between the tensile strength ?b, the threshold stress ?th and the temperature T; establishing the prediction formulas of the minimum creep rate ?th and creep life ?b based on the threshold stress {dot over (?)}m and the tensile strength tƒ; establishing a creep damage constitutive model, including strain rate formula and damage rate formula; obtaining the evolution behavior of strain and deformation with time; obtaining the evolution behavior of damage with time.

Abstract: Methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

Abstract: Disclosed is a method for compiling an equivalent acceleration spectrum of creep under variable temperatures and loads. The method includes following steps: respectively carrying out a material high-temperature tensile test, material high-temperature creep tests and creep tests under two-stage variable temperatures and loads, and calculating values of a parameter p in a creep damage accumulation model under two-stage variable temperatures and loads; based on a nonlinear damage accumulation model under multi-stage variable temperatures and loads, calculating a damage D caused by a multi-stage variable temperatures and loads creep load spectrum by utilizing values of parameter p; based on the principle of consistency of damage D, transforming the multi-stage variable temperatures and loads creep load spectrum into an equivalent acceleration spectrum of a first-order maximum creep load, and finally compiling the equivalent acceleration spectrum of creep under variable temperatures and loads.

Abstract: A methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

Abstract: The present disclosure discloses a method for calculating the service life of a material under the action of a thermal shock load. The method includes steps of obtaining test results at different thermal shock temperatures and a thermal shock cycle number according to a thermal shock test, and calculating a temperature rise rate to temperature drop rate ratio Rv; calculating a corresponding stress intensity factor ?K according to a crack length a measured in the test; calculating a thermal stress ? at the notch and a notch stress concentration coefficient kt of the test specimen; calculating a stress intensity factor threshold ?Kth according to the crack length a measured in the test; and substituting the obtained the stress intensity factor ?K, stress intensity factor threshold ?Kth and temperature rise rate to temperature drop rate ratio Rv into a thermal fatigue crack growth model.

Abstract: A method of controlling a permanent magnet synchronous electric machine (PMSM) drive using a Deadbeat Predictive Current Control (DBPCC) scheme is provided. The method comprises: determining d-axis and q-axis stator current values (id, iq) representative of a measured PMSM current; determining d-axis and q-axis reference current values (id*, iq*); based on the stator current values (id, iq) and the reference current values (id*, iq*), determining d-axis and q-axis current correction values (Cd, Cq); determining corrected reference current values (id**, iq**) as a sum of the reference current values (id*, iq*) and the current correction values (Cd, Cq); and controlling the PMSM drive using the corrected reference current values (id**, iq**) as reference current inputs of the DBPCC scheme. A controller for performing the method; a system comprising the controller, a PMSM and associated power electronics; and a computer program for performing the method are also provided.

Abstract: Disclosed is an equivalent acceleration method of creep loads based on a consistent failure mode. The equivalent acceleration method includes obtaining corresponding tensile strengths; obtaining corresponding creep rupture time; establishing rupture time law, minimum creep rate law and rupture strain law; calculating the value of parameter p in creep damage accumulation model; and dividing the failure mode consistency interval of creep load under variable temperature and variable load. The damage caused by the creep load in the failure mode consistency interval is calculated by using the multi-grade variable temperature and variable load creep nonlinear damage accumulation model, the damage is accelerated to the maximum creep load state in the failure mode consistency interval according to the principle of damage equivalence, and finally the equivalent acceleration of creep load is realized.

Abstract: Disclosed is a method for compiling an equivalent acceleration spectrum of creep under variable temperatures and loads. The method includes following steps: respectively carrying out a material high-temperature tensile test, material high-temperature creep tests and creep tests under two-stage variable temperatures and loads, and calculating values of a parameter p in a creep damage accumulation model under two-stage variable temperatures and loads; based on a nonlinear damage accumulation model under multi-stage variable temperatures and loads, calculating a damage D caused by a multi-stage variable temperatures and loads creep load spectrum by utilizing values of parameter p; based on the principle of consistency of damage D, transforming the multi-stage variable temperatures and loads creep load spectrum into an equivalent acceleration spectrum of a first-order maximum creep load, and finally compiling the equivalent acceleration spectrum of creep under variable temperatures and loads.

Abstract: A connector assembly is configured to connect a first circuit board and a second circuit board. The connector assembly includes a board-to-board connector, a buckle pressing plate and a pressing and covering piece. The buckle pressing plate and the board-to-board connector which is spaced from the buckle pressing plate are arranged on the second circuit board, and the board-to-board connector is connected with the first circuit board to enable the first circuit board to be electrically connected with the second circuit board. The pressing and covering piece includes a covering portion and a buckling portion extending from a first end of the covering portion. The buckling portion is connected to the buckle pressing plate in a buckling manner. The covering portion presses and covers the board-to-board connector to fix the board-to-board connector on the second circuit board. A power supply assembly and an electronic device are also provided.

Abstract: A mobile terminal is provided. The mobile terminal includes: a rear cover; a circuit board; a battery connector; and a fixing member including a first holder arranged on the rear cover and a second holder arranged on the circuit board. The first holder has two first elastic arms, the second holder has two second elastic arms, and each of the two second elastic arms is fastened to each of the two first elastic arms to define a receiving space for receiving the battery connector.

Abstract: An electronic device is provided. The electronic device includes a frame, a sliding seat, and a receiver accommodated in the sliding seat. The frame includes a pair of side walls oppositely disposed and a top wall. The top wall defines an accommodating groove. The accommodating groove extends through the pair of side walls. The sliding seat is slidably disposed in the accommodating groove of the frame. The sliding seat defines a first receiving hole, and the receiver is sealed and covers the first receiving hole of the sliding seat, whereby a sound signal of the receiver is transmitted to outside through the first receiving hole when the sliding seat extends from the accommodating groove. In addition, a terminal device and a method for controlling an electronic device are provided.

Abstract: Disclosed herein is a converter for converting an AC voltage to a DC voltage, the converter comprising: a first H-bridge circuit comprising a first AC terminal for receiving an AC voltage, a second AC terminal, a first DC terminal and a second DC terminal; a second H-bridge circuit comprising a first AC terminal for receiving an AC voltage, a second AC terminal, a first DC terminal and a second DC terminal; an isolation block arranged between the second AC terminal of the first H-bridge circuit and the second AC terminal of the second H-bridge circuit; and a DC voltage output of the converter with a first terminal and a second terminal; wherein: the first terminal of the DC voltage output is connected to the first DC terminal of the first H-bridge circuit and the first DC terminal of the second H-bridge circuit; and the second terminal of the DC voltage output is connected to the second DC terminal of the first H-bridge circuit and the second DC terminal of the second H-bridge circuit.

Abstract: An electrical converter (203) having an active diode-clamped multilevel topology is shown. Each clamping diode is connected in antiparallel with a switch (S5A, S5B). The converter comprises polyphase supply phases (A, B, C) each of which are connected via a respective phase leg (401, 402, 403) to dc rails (301, 302) and a dc-link capacitor. The dc-link capacitor includes a plurality of series-connected capacitors (404, 405). A controller is configured to, in response to an event signal, for each phase leg, activate a combination of switches therein to form a pair of parallel conduction paths to a midpoint (406) between two capacitors in the dc-link capacitor, thereby connecting each phase to the same node.

Abstract: An electronic device is provided. The electronic device includes a frame, a sliding seat, a guiding mechanism, a drive mechanism, and multiple functional components accommodated in the sliding seat. The frame includes a pair of side walls oppositely disposed and a top wall. The top wall defines an accommodating groove. The accommodating groove extends through the pair of side walls. The sliding seat is slidably connected with the frame in the accommodating groove via the drive mechanism, and the guiding mechanism is disposed between the sliding seat and the frame, whereby the sliding seat driven by the drive mechanism extends from or is accommodated in the accommodating groove along a guiding direction of the guiding mechanism. The sliding seat is provided with at least one functional portion, whereby the multiple functional components are able to transmit a signal through the at least one functional portion.