Abstract: A transducer for non-invasive measurement includes: at least one first piezoelectric element; a second piezoelectric element; and a base material mountable to a wall of a vessel that contains a liquid. The base material has a planar portion and an angular shaped portion. The angular shaped portion has a plurality of outer faces, a first face of the plurality of outer faces of the angular shaped portion being connected to (or part of) a first face of the planar portion, a second face of the planar portion opposite to the first face of the planar portion being mountable to the wall of the vessel, at least one second face of the plurality of outer faces of the angular shaped portion being angled to the first face of the angular shaped portion at an angle less than an angle of 90 degrees internal to the base material.

Abstract: A transducer for non-invasive measurement includes: a shear-type piezoelectric element; and a host material. The shear-type piezoelectric element is mounted to a first face of the host material. A second face of the host material is mountable to a wall of a vessel that holds a liquid. When the second face of the host material is mounted to the wall of the vessel, the transducer when activated at an activation frequency launches a Lamb wave into the wall of the vessel. The transducer is designed such that a phase velocity of the Lamb wave in the wall of the vessel is greater than a speed of sound in the liquid held by the vessel.

Abstract: A method of determining a mixing state of a medium in a container includes: transmitting a plurality of acoustic signals at least partly through the medium and receiving the plurality of acoustic signals after at least partly traversing the medium; determining at least one propagation value of at least one propagation quantity for each of the plurality of received acoustic signals to provide determined propagation values, each at least one propagation quantity being indicative of an interaction of the acoustic signals with the medium; determining at least one fluctuation value of at least one fluctuation quantity based on the determined propagation values to provide a determined at least one fluctuation value, each at least one fluctuation quantity being indicative of and/or correlating with a variance of the determined propagation values and/or with a state of a mixture; and determining the mixing state of the medium.

Abstract: A transducer for non-invasive measurement includes: a piezoelectric element; a base plate; and driver electronics. The piezoelectric element is mounted to a first face of the base plate. A second face of the base plate is mountable to a wall of a vessel that holds a liquid. The driver electronics drive the piezoelectric element at a plurality of activation frequencies. When the second face of the base plate is mounted to the wall of the vessel, the transducer when activated excites acoustic waves in the base plate and to launch an acoustic wave into the liquid. The transducer is designed such that an angular divergence of the acoustic wave launched into the liquid varies as a function of at least the activation frequency and a dimension of an emitter.

Abstract: A transducer for non-invasive measurement includes: at least one first piezoelectric element; a second piezoelectric element; and a base material mountable to a wall of a vessel that contains a liquid. The base material has a planar portion and an angular shaped portion. The angular shaped portion has a plurality of outer faces, a first face of the plurality of outer faces of the angular shaped portion being connected to (or part of) a first face of the planar portion, a second face of the planar portion opposite to the first face of the planar portion being mountable to the wall of the vessel, at least one second face of the plurality of outer faces of the angular shaped portion being angled to the first face of the angular shaped portion at an angle less than an angle of 90 degrees internal to the base material.

Abstract: A transducer for non-invasive measurement includes: a shear-type piezoelectric element; and a host material. The shear-type piezoelectric element is mounted to a first face of the host material. A second face of the host material is mountable to a wall of a vessel that holds a liquid. When the second face of the host material is mounted to the wall of the vessel, the transducer when activated at an activation frequency launches a Lamb wave into the wall of the vessel. The transducer is designed such that a phase velocity of the Lamb wave in the wall of the vessel is greater than a speed of sound in the liquid held by the vessel.