A calibration system for a pulsed phase-lock loop ultrasound measurement system comprising an apparatus having a compartment for holding a pressure sensitive liquid. The compartment has an opening by which a flow of the pressure sensitive liquid may be controlled. A sensor arranged relative to the compartment to receive ultrasonic signals that reflect off one or more inner surfaces of the compartment. The system includes a processing device for receiving an integrated error signal output by the sensor based on pressure changes of the pressure sensitive liquid responsive to a change in flow of pressure sensitive liquid between the source and the compartment.

A calibration system for a pulsed phase-lock loop ultrasound measurement system comprising an apparatus having a compartment for holding a pressure sensitive liquid. The compartment has an opening by which a flow of the pressure sensitive liquid may be controlled. A sensor arranged relative to the compartment to receive ultrasonic signals that reflect off one or more inner surfaces of the compartment. The system includes a processing device for receiving an integrated error signal output by the sensor based on pressure changes of the pressure sensitive liquid responsive to a change in flow of pressure sensitive liquid between the source and the compartment.

Methods and systems for measuring pipe parameters using guided acoustic wave modes are provided. The method includes receiving data corresponding to an acoustic signal, wherein the data are obtained by transmitting an excitation pulse at a specified frequency and detecting the resulting acoustic signal using an acoustic transducer attached to the outer surface of the pipe wall. The method includes analyzing the data to identify guided acoustic wave modes including at least two of: a C-SH acoustic wave mode that travels within the pipe wall; a C-LT acoustic wave mode that travels within the near-surface region of the pipe wall; and/or a CA acoustic wave mode that travels within the pipe cavity. The method includes calibrating the parameter measurement using the C-SH acoustic wave mode and determining the parameter measurement based on the phase velocity and/or the amplitude of the C-LT acoustic wave mode and/or the CA acoustic wave mode.

An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).

An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).

An image forming apparatus comprises an ultrasonic sensor and a processor is configured to control the image forming apparatus based on an output signal of the ultrasonic sensor. The processor estimates a barometric pressure based on the output signal of the ultrasonic sensor and determines an image forming condition based on the estimated barometric pressure. The ultrasonic sensor is utilized for controlling the image forming apparatus and for estimating the barometric pressure.

An image forming apparatus comprises an ultrasonic sensor and a processor is configured to control the image forming apparatus based on an output signal of the ultrasonic sensor. The processor estimates a barometric pressure based on the output signal of the ultrasonic sensor and determines an image forming condition based on the estimated barometric pressure. The ultrasonic sensor is utilized for controlling the image forming apparatus and for estimating the barometric pressure.

A method for manufacturing an element forming wafer includes the steps of: forming a thin layer on a semiconductor wafer having a plurality of chip forming regions; and adjusting stress generated in an element forming portion of the thin layer to have a specified value. The thin layer constitutes an element in each of the plurality of chip forming regions. The step of adjusting the stress includes: arranging a resist on the thin layer; exposing the resist to light using a photomask having openings; forming openings in the resist by developing the resist; and performing ion-implantation using the resist as a mask. The photomask used during the step of exposing the resist to light has a ratio of the openings that is adjusted based on the stress generated in the element forming portion.

A method of measuring a pressure of a fluid adjacent a wall of a pipe or vessel. A transducer is attached to the wall of the pipe or vessel. A signal is transmitted by the transducer at a characteristic frequency via a plurality of guided wave modes. The characteristic frequency is a frequency at which the guided wave modes are separated in time from each other when received. The signal is received after the plurality of guided wave modes travel in or through the wall a predetermined number of times. The signal has a signal receipt time after the predetermined number of times. The pressure of the fluid is calculated using the signal receipt time.

Pressure and pressure or displacement variations are measured in a media, such as a fluid (e.g., air, other gases, or other liquid fluids), using ultrasound. The pressure may be sound pressure (e.g., acoustic pressure), pseudo-sound pressure (e.g., hydrodynamic pressure), displacement, and so on. By measuring pressure or displacement, the flow in the fluid can be measured, estimated, parameterized, or otherwise quantified. In this way, measurements of pressure (e.g., acoustic pressure, hydrodynamic pressure) or displacement can be correlated or otherwise converted into a measurement of flow. The pressure measurements can also be converted into audio signals that can be played back to a user.