Abstract: An apparatus (100) for mixing a fluid (F) comprises a mixing container (10) with a container wall (11) for holding the fluid (F). One or more acoustic transducers (21, 22) are arranged on the container wall (11) and configured to generate respective acoustic waves (W1, W2) directed into the fluid (F) for causing a respective flow pattern (F1, F2) in the fluid (F) by acoustic streaming. A controller (15) is configured to control the acoustic transducers (21, 22) to automatically switch between generation of different acoustic waves (W1, W2) for causing switching between different flow patterns (F1, F2).

Abstract: Methods and systems for subsurface imaging of nanostructures buried inside a plate shaped substrate are provided. An ultrasonic generator at a side face of the substrate is used to couple ultrasound waves (W) into an interior of the substrate. The interior has or forms a waveguide for propagating the ultrasound waves (W) in a direction (X) along a length of the substrate transverse to the side face. The nanostructures are imaged using an AFM tip to measure an effect (E) at the top surface caused by direct or indirect interaction of the ultrasound waves (W) with the buried nanostructures.

Abstract: A cantilever (30) for an ultrasound acoustic microscopy device is provided comprising a transmission tip (31) to contact a sample (11) to therewith transmit an ultrasound acoustic signal as an ultrasound acoustic wave into the sample. The cantilever further comprises a reception tip (32) separate from the transmission tip (31) to contact the sample to receive an acoustic signal resulting from reflections of the ultrasound wave from within the sample.

Abstract: The document relates to a method of performing subsurface imaging of embedded structures underneath a substrate surface, using an atomic force microscopy system. The system comprises a probe with a probe tip, and a sensor for sensing a position of the probe tip. The method comprises the steps of: positioning the probe tip relative to the substrate: applying a first acoustic input signal to the substrate; applying a second acoustic input signal to the substrate; detecting an output signal from the substrate in response to the first and second acoustic input signal; and analyzing the output signal. The first acoustic input signal comprises a first signal component and a second signal component, the first signal component comprising a frequency below 250 megahertz and the second signal component either including a frequency below 2.5 megahertz or a frequency such as to provide a difference frequency of at most 2.

Abstract: Ultrasonic measurements of fluid properties are performed with the aid of an optical fiber or a package of optical fibers by exciting ultrasound waves at a first location along the optical fiber in the fluid by means of light from the optical fiber and detecting an effect of the ultrasound waves on light reflection or propagation in the optical fiber and/or a further optical fiber in the package at a second location along the optical fiber or at the end of the optical fiber.

Abstract: A method and system for performing subsurface atomic force microscopy measurements, the system comprising: a signal source for generating an drive signal; a transducer configured to receive the drive signal for converting the drive signal into vibrational waves and coupling said vibrational waves into a stack comprising a sample for interaction with subsurface features within said sample; cantilever tip for contacting the sample for measuring surface displacement resulting from the vibrational waves to determine subsurface features; wherein the system includes a measurement device for measuring a measurement signal returning from the transducer during and/or in between the subsurface atomic force microscopy measurements.

Abstract: Methods and systems for measuring a fluid flow comprise a plurality of transceivers disposed at predetermined locations distributed along a perimeter around the fluid flow. The transceivers transmit and receive acoustic signals through the fluid flow there between. A plurality of different acoustic paths through the fluid flow are formed between different transceiver pairs. Different time intervals are measured between respective times of transmitting and receiving the acoustic signals; and along the plurality of different acoustic paths. A velocity map of the fluid flow is calculated by fitting the measured different time intervals to a model of the fluid flow. The model of the fluid flow defines a velocity map with different flow velocities in a cross-section plane transverse to the fluid flow.

Abstract: A nondestructive method of monitoring scale buildup in a section of pipe includes: transmitting, from a first transducer at a first location of the pipe, axisymmetric torsional ultrasonic guided waves (UGWs) to propagate along the pipe, the torsional UGWs spanning a frequency band comprising multiple higher order modes; receiving, by a second transducer at a second location of the pipe, the propagated torsional UGWs; and determining a thickness of the scale buildup in the pipe between the first location and the second locations using the received torsional UGWs. The determining step comprises: measuring attributes from the received torsional UGWs, the attributes being first arrival times or mode cutoff frequencies; comparing the measured attributes to sets of computed said attributes, each set representing a different scale buildup thickness; and selecting the compared set of computed attributes that is closest to the measured attributes.

Abstract: A method of performing atomic force microscopy (AFM) measurements, uses an ultrasound transducer to transmit modulated ultrasound waves with a frequency above one GHz from the ultrasound transducer to a top surface of a sample through the sample from the bottom surface of the sample. Effects of ultrasound wave scattering are detected from vibrations of an AFM cantilever at the top surface of the sample. Before the start of the measurements, a drop of a liquid is placed on a top surface of the ultrasound transducer. The sample is placed on the top surface of the ultrasound transducer, whereby the sample presses the liquid in the drop into a layer of the liquid between the top surface of the ultrasound transducer and a bottom surface of the sample. The AFM measurements are started after a thickness of the layer of the liquid has stabilized.

Abstract: Atomic force microscopy system comprising an atomic force microscopy device and a substrate carrier having a carrier surface carrying a substrate. The substrate has a substrate main surface and a substrate scanning surface opposite the substrate main surface. The atomic force microscopy device comprises a scan head including a probe. The probe comprises a cantilever and a probe tip arranged on the cantilever. The atomic force device further comprises an actuator cooperating with at least one of the scan head or the substrate carrier for moving the probe tip and the substrate carrier relative to each other in one or more directions parallel to the carrier surface for scanning of the substrate scanning surface with the probe tip. A signal application actuator applies, during said scanning, an acoustic input signal to the substrate, said acoustic input signal generating a first displacement field in a first displacement direction only.

Abstract: Methods and systems for subsurface imaging of nanostructures buried inside a plate shaped substrate are provided. An ultrasonic generator at a side face of the substrate is used to couple ultrasound waves (W) into an interior of the substrate. The interior has or forms a waveguide for propagating the ultrasound waves (W) in a direction (X) along a length of the substrate transverse to the side face. The nanostructures are imaged using an AFM tip to measure an effect (E) at the top surface caused by direct or indirect interaction of the ultrasound waves (W) with the buried nanostructures.

Abstract: A fluid density measuring device uses a pipe with a pipe wall that has an inner wall surface with a non-circular cross-section at least in an axial segment of the pipe. Preferably, the inner wall surface comprises one or more protrusions extending inwardly into the pipe and along the axial direction of the pipe. An ultrasound transducer located on the pipe wall is used to generate local motion of the pipe wall with a circumferential direction of motion. Preferably, the ultrasound transducer is located between successive protrusions. An ultrasound receiver located on the pipe wall receives an ultrasound torsion wave generated by the local motion after the torsion wave has traveled through the axial section wherein the inner wall surface has a non-circular cross-section. The fluid density is determined from the propagation speed of the torsion wave.

Abstract: A method of performing atomic force microscopy (AFM) measurements, uses an ultrasound transducer to transmit modulated ultrasound waves with a frequency above one GHz from the ultrasound transducer to a top surface of a sample through the sample from the bottom surface of the sample. Effects of ultrasound wave scattering are detected from vibrations of an AFM cantilever at the top surface of the sample. Before the start of the measurements a drop of a liquid is placed on a top surface of the ultrasound transducer. The sample is placed on the top surface of the ultrasound transducer, whereby the sample presses the liquid in the drop into a layer of the liquid between the top surface of the ultrasound transducer and a bottom surface of the sample. The AFM measurements are started after a thickness of the layer of the liquid has stabilized.

Abstract: Atomic force microscopy system comprising an atomic force microscopy device and a substrate carrier having a carrier surface carrying a substrate. The substrate has a substrate main surface and a substrate scanning surface opposite the substrate main surface. The atomic force microscopy device comprises a scan head including a probe. The probe comprises a cantilever and a probe tip arranged on the cantilever. The atomic force device further comprises an actuator cooperating with at least one of the scan head or the substrate carrier for moving the probe tip and the substrate carrier relative to each other in one or more directions parallel to the carrier surface for scanning of the substrate scanning surface with the probe tip. A signal application actuator applies, during said scanning, an acoustic input signal to the substrate, said acoustic input signal generating a first displacement field in a first displacement direction only.

Abstract: The present disclosure concerns a method and apparatus for measuring a sensor (10) comprising multiple optical resonators (11, 12) optically connected to a single optical output interface (16). The optical resonators (11, 12) are interrogated with a light input signal (Si). A light output signal (So) is measured from the optic al output interface (16) to determine a combined spectral response (Sa) covering a wavelength range (W) including a plurality of resonance peaks (?1,i, ?2,j) for each of the optical resonators (11, 12). A Fourier transform spectrum (FT) of the combined spectral response (Sa) is calculated and a harmonic series of periodic peaks (n·f1) is identified in the Fourier transform spectrum (FT). The harmonic series of periodic peaks is filtered to obtain a filtered Fourier transform spectrum (FT1) and a sensor signal is calculated (X1) based on the filtered Fourier transform spectrum (FT1).

Abstract: Methods and systems for measuring a fluid flow comprise a plurality of transceivers disposed at predetermined locations distributed along a perimeter around the fluid flow. The transceivers transmit and receive acoustic signals through the fluid flow there between. A plurality of different acoustic paths through the fluid flow are formed between different transceiver pairs. Different time intervals are measured between respective times of transmitting and receiving the acoustic signals; and along the plurality of different acoustic paths. A velocity map of the fluid flow is calculated by fitting the measured different time intervals to a model of the fluid flow. The model of the fluid flow defines a velocity map with different flow velocities in a cross-section plane transverse to the fluid flow.

Abstract: The present invention relates to a method of performing subsurface imaging of embedded structures in a substrate underneath a substrate surface, the method comprising the steps of applying, using a signal application actuator, an acoustic input signal to the substrate, detecting, using a vibration sensor, a return signal from the substrate and analyzing the return signal for obtaining information on the embedded structures, for enabling imaging thereof wherein the step of applying the acoustic input signal comprises applying a discontinuous signal of an acoustic signal component to the substrate, the acoustic signal component having a frequency above 1 gigahertz, such that the return signal includes a scattered fraction of the discontinuous signal scattered from the embedded structures. The invention further relates to a system.

Abstract: The document relates to a method of performing subsurface imaging of embedded structures underneath a substrate surface, using an atomic force microscopy system. The system comprises a probe with a probe tip, and a sensor for sensing a position of the probe tip. The method comprises the steps of: positioning the probe tip relative to the substrate: applying a first acoustic input signal to the substrate; applying a second acoustic input signal to the substrate; detecting an output signal from the substrate in response to the first and second acoustic input signal; and analyzing the output signal. The first acoustic input signal comprises a first signal component and a second signal component, the first signal component comprising a frequency below 250 megahertz and the second signal component either including a frequency below 2.5 megahertz or a frequency such as to provide a difference frequency of at most 2.

Abstract: The present invention relates to a heterodyne scanning probe microscopy method for imaging structures on or below the surface of a sample, the method including applying, using a transducer, an acoustic input signal to the sample sensing, using a probe including a probe tip in contact with the surface, an acoustic output signal, wherein the acoustic output signal is representative of acoustic surface waves induced by the acoustic input signal wherein the acoustic input signal comprises at least a first signal component having a frequency above 1 gigahertz, and wherein for detecting of the acoustic output signal the method comprises a step of applying a further acoustic input signal to at least one of the probe or the sample for obtaining a mixed acoustic signal, the further acoustic input signal including at least a second signal component having a frequency above 1 gigahertz, wherein the mixed acoustic signal comprises a third signal component having a frequency equal to a difference between the first frequen

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.