Abstract: Properties of a medium, such as its particle size distribution, are characterized using a measurement cell containing a medium between walls of the cell, with ultrasound transducers on opposite walls. Ultrasound is transmitted from the ultrasound transducers on both sides and transmission and reflection responses are detected. An ultrasound frequency dependent ratio of a Fourier transform value of a product of signals obtained from transmission responses in opposite directions and a Fourier transform value of a product of signals obtained from reflections at the transducers is computed. Preferably, the first received reflected and transmitted pulses in response to pulse excitation are used to compute the ratio. Ultrasound frequency dependent ultrasound speed and/or attenuation data of ultrasound in the medium are computed as a function of the ultrasound frequency from the ratio. This eliminates the effect of the walls.

Abstract: A portable device for inspecting a weld of metal tubes, comprises: at least one clamp formed from two jaws, each jaw including a circularly arcuate void defining, once the clamp has been closed, a substantially circular slot suitable for receiving a tube the weld of which is to be inspected; at least two multielement ultrasound probes that are mounted to be movable relative to the inspecting device and to be able to rotate relative to an axis passing through the center of the two lateral portions of the substantially circular slot of a clamp; a means configured to drive the ultrasound probes to rotate to pass around the entire circumference of the weld to be inspected; and an angular sensor configured to deliver a signal representative of the angular position of at least one sensor relative to an initial position.

Abstract: Properties of a medium, such as its particle size distribution, are characterized using a measurement cell containing a medium between walls of the cell, with ultrasound transducers on opposite walls. Ultrasound is transmitted from the ultrasound transducers on both sides and transmission and reflection responses are detected. An ultrasound frequency dependent ratio of a Fourier transform value of a product of signals obtained from transmission responses in opposite directions and a Fourier transform value of a product of signals obtained from reflections at the transducers is computed. Preferably, the first received reflected and transmitted pulses in response to pulse excitation are used to compute the ratio. Ultrasound frequency dependent ultrasound speed and/or attenuation data of ultrasound in the medium are computed as a function of the ultrasound frequency from the ratio. This eliminates the effect of the walls.