A device for measuring the power and wavelength of laser radiation via the photoacoustic effect, includes a cell containing at least one gas having an absorption line with a central wavelength .sub.c, an electro-acoustic transducer arranged within the cell and suitable for generating a signal representative of the photoacoustic signal in the cell, means for processing the signal generated by the electro-acoustic transducer, wherein an estimate of the concentration of the one or more gases is stored, at least one laser source suitable for emitting, into the cell, laser radiation at a wavelength suitable for exciting at least one gas contained in the cell, the laser radiation having a wavelength that is variable in an oscillatory manner about an average wavelength .sub.moy at a modulation frequency (f.sub.1), such that an interaction between the laser radiation and at least one gas contained in the cell induces generation of a photoacoustic signal at a detection frequency of the electro-acoustic transducer, the cell being sealed by a membrane so as to be impermeable to the one or more gases contained in the cell and having an optical aperture transparent to the laser radiation, the processing means being configured to determine a variation in the phase (t) of the photoacoustic signal based on the photoacoustic signal, the processing means being suitable for measuring the wavelength of the radiation based on the photoacoustic signal.

A crack detecting system includes a tool movable along a conduit or structure and having at least one sensing device for sensing cracks in a wall of the conduit or structure. The sensing device includes a fluid emitter and the fluid emitter includes at least one orifice configured to emit fluid. In response to the orifice emitting fluid, the emitted fluid excites the conduit or structure and the sensing device senses a response from the excitation of the conduit or structure. A processor is operable to process the response sensed by the sensing device and responsive to the processing, the processor determines flaws present at the wall of the conduit or structure.

A fluid sensor includes a housing and a thermal emitter in the housing to emit first thermal radiation into a detection volume of the housing at a first power level during a measurement interval and emit the first thermal radiation at a reduced first power level or not emit said first thermal radiation at all during an intermediate interval disposed outside of the measurement interval. The fluid sensor includes a measuring element in the detection volume to receive a radiation signal during the measurement interval. The fluid sensor includes a second thermal emitter in the housing to emit second thermal radiation at a second power level into the detection volume during the intermediate interval such that a thermal oscillation of thermal radiation in relation to an overall power level of the thermal radiation in the detection volume is at most 50% during the measurement interval and the intermediate interval.

An electronic device includes air input sensors that gather air input from a user's fingers, a stylus, or other object in a volume of air near the electronic device. The air input sensors include ultrasonic transducers that emit ultrasonic signals towards the volume of air and that detect the ultrasonic signals after the signals reflect from the external object. Using time-of-flight measurement techniques, control circuitry tracks the movement of the external object in the volume of air near the electronic device. A display provides visual feedback of the air input, such as shadows that preview where the input will be directed to on the display. The volume of air where input is detected is divided into multiple input zones that trigger different actions from the electronic device. The ultrasonic transducers include acoustic lenses.

A non-contact non-destructive testing method includes spatially and/or temporally controlling a laser excitation light based on a predetermined pattern. The laser excitation light is projected onto a surface of a test object to generate acoustic waves on the test object. The acoustic waves apply stress loading to the test object. The method also includes imaging the test object with and without stress loading using shearography imaging, and analyzing shearography imaging data to determine a presence of a defect in the test object.

Method and system are disclosed for characterizing and quantifying composite laminate structures. The method and system take a composite laminate of unknown ply stack composition and sequence and determine various information about the individual plies, such as ply stack, orientation, microstructure, and type. The method and system distinguishes between weave types that exhibit similar planar stiffness behaviors, but which produce different failure mechanisms. Individual ply information then is used to derive the laminate bulk properties from externally provided constitutive properties of the fiber and matrix, including extensional stiffness, bending-extension coupling stiffness, bending stiffness, and the like. The laminate bulk properties are then used to generate a probabilistic failure envelope for the composite laminate. This provides the ability to perform non-destructive QA to ensure that individual lamina layup was accomplished according to specifications, and results are used to identify numerous laminate properties beyond purely structural ones.

A single channel scanning acoustic microscope that increases the throughput of the acoustic imaging system by connecting a multi-transducer assembly in parallel to a single channel electronic circuit. The single channel scanning acoustic microscope includes multiple transducers configured to generate a time delay for individual ultrasonic waves generated by each transducer, wherein a pulse generator simultaneously sends a pulse signal to the multi-transducer assembly.

According to an embodiment, a linear-scan ultrasonic inspection apparatus comprises: an ultrasonic array probe having ultrasonic elements aligned in a first direction; a delay-time calculator configured to calculate, referring to the surface shape of the test object, values of delay time of at least one of transmitting and receiving ultrasonic wave; an overlapping-region adjustor configured to set conditions for generating an image of an overlapping region; and an integrated-image generator configured to generate first image data of a region including the overlapping region. The overlapping-region adjustor is configured to set the conditions of the surface shape to be referred to the delay-time calculator in calculating the values of the delay time at either the first-probe setting position or the second-probe setting position as both of a first acquired shape obtained at the first-probe setting position and a second acquired shape obtained at the second-probe setting position.

In accordance with a method for characterization of particles in a fluid-filled hollow structure, an ultrasound signal with a frequency spectrum, which exhibits a local maximum at a variable measurement frequency, is emitted in the direction of a part area of the hollow structure and reflected components are detected. The measurement frequency is tuned in a predetermined measurement interval, and depending on the detected reflected components, a spectral response curve is acquired as a function of the measurement frequency. Depending on the response curve, at least one characteristic property for a part of the particles located in the part area of the hollow structure is determined. The characteristic property includes a measure for an adhesion of the particles of the part of the particles located in the part area of the hollow structure.

Methods and devices for imaging wells using ultrasound is described. The devices include a modular imaging device having a telemetry module and a radial imaging module and/or forward imaging module. The radial imaging module includes a ring shaped phased array ultrasonic transducer array for generating images on the length of a wellbore. Various lens and housing configurations for the radial imaging module are described. The forward imaging module includes an ultrasonic transducer comprising one or more elements and having an adjustable viewpoint for generating images of obstructions found in a wellbore. Advanced imaging modes for a radial imaging module include multiple aperture and spiral wave imaging mode.