Abstract: A dual frequency ultrasonic and sonic actuator with constrained impact mass is presented. According to one aspect, displacement of the impact mass is constrained by cavity to which ultrasonic stress from the tip of a horn is applied. According to another aspect, the displacement of the impact mass is constrained by a spring attached to the tip of the horn. According to another aspect, the displacement of the impact mass is constrained by a flexure. The constrained impact mass converts the ultrasonic stress to lower frequency sonic stress that is coupled to a transmitting element for transmission through a surface. According to one aspect, the transmitting element is a longitudinal probe. According to another aspect, the transmitting element is a drill bit used to penetrate though the surface. According to another aspect, the transmitting element is a thumper used to transmit elastic waves though the surface.

Abstract: An ultrasonic actuator with increased radiating surface is presented. The increased radiating surface is provided by a plurality of piezoelectric stacks that are each compressed by action of a respective bolt against a common backing structure of the actuator. According to one aspect, each of the stacks includes a plurality of stacked piezoelectric rings with the respective bolt arranged through the central opening of the rings. According to another aspect, one or both of the backing structure and the horn of the actuator include tuning grooves and/or tuning slots to produce amplitude uniformity of displacement through the actuator. According to another aspect, the radiating surface has a symmetrical shape about an axial direction of the actuator with a lateral dimension that is in a range between one quarter and one half of the wavelength of operation of the actuator.

Abstract: A flow energy harvesting system including a nozzle-diffuser defining a spline-shaped flow channel and a flow energy harvesting device in the spline-shaped flow channel of the nozzle-diffuser. The spline-shaped flow channel includes a converging portion, a diverging portion, and a constriction section between the converging and diverging portions. The flow energy harvesting device includes a flextensional member having a frame and a cantilever extending outward from the frame, and a stack of piezoelectric elements housed in an interior cavity defined in the frame. The cantilever is a non-piezoelectric material. The frame of the flextensional member is in the converging portion and the cantilever is in the constriction section of the spline-shaped flow channel. The frame is configured to deform and elongate the piezoelectric elements to generate a current based on the piezoelectric effect when a fluid flows through the spline-shaped flow channel and generates unbalanced forces on the cantilever due.

Abstract: An ultrasonic actuator with increased radiating surface is presented. The increased radiating surface is provided by a plurality of piezoelectric stacks that are each compressed by action of a respective bolt against a common backing structure of the actuator. According to one aspect, each of the stacks includes a plurality of stacked piezoelectric rings with the respective bolt arranged through the central opening of the rings. According to another aspect, one or both of the backing structure and the horn of the actuator include tuning grooves and/or tuning slots to produce amplitude uniformity of displacement through the actuator. According to another aspect, the radiating surface has a symmetrical shape about an axial direction of the actuator with a lateral dimension that is in a range between one quarter and one half of the wavelength of operation of the actuator.

Abstract: A high temperature ultrasonic probe and a mounting fixture for attaching and aligning the probe to a steam pipe using blind alignment. The high temperature ultrasonic probe includes a piezoelectric transducer having a high temperature. The probe provides both transmitting and receiving functionality. The mounting fixture allows the high temperature ultrasonic probe to be accurately aligned to the bottom external surface of the steam pipe so that the presence of liquid water in the steam pipe can be monitored. The mounting fixture with a mounted high temperature ultrasonic probe are used to conduct health monitoring of steam pipes and to track the height of condensed water through the wall in real-time.

Abstract: A multi-probe system for real-time measurement of a fluid level in a pipe with steady-state and turbulent flow conditions is presented. The multi-probe system includes a plurality of multiplexed transducers attached in a non-destructive fashion to walls of the pipe. Multiplexing of the transducers activate and deactivate the transducers in sequence to generate independent pairs of transmit and receive wave signals through the pipe. Each transmit and receive signal pair can be used to independently establish a time-of-flight from the transducer and back to the transducer as reflected by a surface of the fluid. The transducers can be arranged as longitudinal and/or circumferential arrays on the walls of the pipe. An algorithm that determines the time-of-flight eliminates received signals having an energy level lower than or equal to a predefined minimum energy level and eliminates any time-of-flight that is shorter than a minimum threshold time.

Abstract: A dual frequency ultrasonic and sonic actuator with constrained impact mass is presented. According to one aspect, displacement of the impact mass is constrained by cavity to which ultrasonic stress from the tip of a horn is applied. According to another aspect, the displacement of the impact mass is constrained by a spring attached to the tip of the horn. According to another aspect, the displacement of the impact mass is constrained by a flexure. The constrained impact mass converts the ultrasonic stress to lower frequency sonic stress that is coupled to a transmitting element for transmission through a surface. According to one aspect, the transmitting element is a longitudinal probe. According to another aspect, the transmitting element is a drill bit used to penetrate though the surface. According to another aspect, the transmitting element is a thumper used to transmit elastic waves though the surface.

Abstract: An arterial blockage percussive drill having a guiding sleeve, a drilling wire slidably coupled to the guiding sleeve and a percussive actuator coupled to the drilling wire to longitudinally oscillate the drilling wire into an arterial blockage.

Abstract: A flow energy harvesting system including a nozzle-diffuser defining a spline-shaped flow channel and a flow energy harvesting device in the spline-shaped flow channel of the nozzle-diffuser. The spline-shaped flow channel includes a converging portion, a diverging portion, and a constriction section between the converging and diverging portions. The flow energy harvesting device includes a flextensional member having a frame and a cantilever extending outward from the frame, and a stack of piezoelectric elements housed in an interior cavity defined in the frame. The cantilever is a non-piezoelectric material. The frame of the flextensional member is in the converging portion and the cantilever is in the constriction section of the spline-shaped flow channel. The frame is configured to deform and elongate the piezoelectric elements to generate a current based on the piezoelectric effect when a fluid flows through the spline-shaped flow channel and generates unbalanced forces on the cantilever due.

Abstract: A multi-probe system for real-time measurement of a fluid level in a pipe with steady-state and turbulent flow conditions is presented. The multi-probe system includes a plurality of multiplexed transducers attached in a non-destructive fashion to walls of the pipe. Multiplexing of the transducers activate and deactivate the transducers in sequence to generate independent pairs of transmit and receive wave signals through the pipe. Each transmit and receive signal pair can be used to independently establish a time-of-flight from the transducer and back to the transducer as reflected by a surface of the fluid. The transducers can be arranged as longitudinal and/or circumferential arrays on the walls of the pipe. An algorithm that determines the time-of-flight eliminates received signals having an energy level lower than or equal to a predefined minimum energy level and eliminates any time-of-flight that is shorter than a minimum threshold time.

Abstract: An arterial blockage percussive drill having a guiding sleeve, a drilling wire slidably coupled to the guiding sleeve and a percussive actuator coupled to the drilling wire to longitudinally oscillate the drilling wire into an arterial blockage.

Abstract: A high temperature ultrasonic probe and a mounting fixture for attaching and aligning the probe to a steam pipe using blind alignment. The high temperature ultrasonic probe includes a piezoelectric transducer having a high temperature. The probe provides both transmitting and receiving functionality. The mounting fixture allows the high temperature ultrasonic probe to be accurately aligned to the bottom external surface of the steam pipe so that the presence of liquid water in the steam pipe can be monitored. The mounting fixture with a mounted high temperature ultrasonic probe are used to conduct health monitoring of steam pipes and to track the height of condensed water through the wall in real-time.

Abstract: A high temperature ultrasonic probe and a mounting fixture for attaching and aligning the probe to a steam pipe using blind alignment. The high temperature ultrasonic probe includes a piezoelectric transducer having a high temperature. The probe provides both transmitting and receiving functionality. The mounting fixture allows the high temperature ultrasonic probe to be accurately aligned to the bottom external surface of the steam pipe so that the presence of liquid water in the steam pipe can be monitored. The mounting fixture with a mounted high temperature ultrasonic probe are used to conduct health monitoring of steam pipes and to track the height of condensed water through the wall in real-time.

Abstract: A flow energy harvesting device having a harvester pipe includes a flow inlet that receives flow from a primary pipe, a flow outlet that returns the flow into the primary pipe, and a flow diverter within the harvester pipe having an inlet section coupled to the flow inlet, a flow constriction section coupled to the inlet section and positioned at a midpoint of the harvester pipe and having a spline shape with a substantially reduced flow opening size at a constriction point along the spline shape, and an outlet section coupled to the constriction section. The harvester pipe may further include a piezoelectric structure extending from the inlet section through the constriction section and point such that the fluid flow past the constriction point results in oscillatory pressure amplitude inducing vibrations in the piezoelectric structure sufficient to cause a direct piezoelectric effect and to generate electrical power for harvesting.

Abstract: A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

Abstract: A flow energy harvesting device having a harvester pipe includes a flow inlet that receives flow from a primary pipe, a flow outlet that returns the flow into the primary pipe, and a flow diverter within the harvester pipe having an inlet section coupled to the flow inlet, a flow constriction section coupled to the inlet section and positioned at a midpoint of the harvester pipe and having a spline shape with a substantially reduced flow opening size at a constriction point along the spline shape, and an outlet section coupled to the constriction section. The harvester pipe may further include a piezoelectric structure extending from the inlet section through the constriction section and point such that the fluid flow past the constriction point results in oscillatory pressure amplitude inducing vibrations in the piezoelectric structure sufficient to cause a direct piezoelectric effect and to generate electrical power for harvesting.

Abstract: A high temperature ultrasonic probe and a mounting fixture for attaching and aligning the probe to a steam pipe using blind alignment. The high temperature ultrasonic probe includes a piezoelectric transducer having a high temperature. The probe provides both transmitting and receiving functionality. The mounting fixture allows the high temperature ultrasonic probe to be accurately aligned to the bottom external surface of the steam pipe so that the presence of liquid water in the steam pipe can be monitored. The mounting fixture with a mounted high temperature ultrasonic probe are used to conduct health monitoring of steam pipes and to track the height of condensed water through the wall in real-time.

Abstract: A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

Abstract: Piezoelectric compounds of the formula xNamBinTiO3-yKmBinTiO3-zLimBinTiO3-pBaTiO3 where (0<x?1), (0?y?1), (0?z?1), (0.3?m?0.7), (0.3?n?0.7), (0<p?1) (0.9?m/n?1.1) as well as to doped variations thereof are disclosed. The material is suitable for high power applications.

Abstract: Piezoelectric compounds of the formula xNamBinTiO3-yKmBinTiO3-zLimBinTiO3-pBaTiO3 where (0<x?1), (0?y?1), (0?z?1), (0.3?m?0.7), (0.3?n?0.7), (0<p?1) (0.9?m/n?1.1) as well as to doped variations thereof are disclosed. The material is suitable for high power applications.