Abstract: A method of modeling a surface of an object using ultrasonic transducers mounted on the surface by: providing a model of the surface comprising a primary set of surface points indicative of the height of the surface, transmitting pulsed waves from a first transducer to one or more second transducers along respective paths along the surface, measuring travel times of the pulsed waves along each path, calculating travel times based on the model of the surface, adjusting the model of the surface in response to any discrepancies between the measured travel times and the calculated travel times. The above steps are repeated until the discrepancies are smaller than a predetermined threshold. The step of calculating the travel times comprises interpolating the primary set of surface points in order to obtain an expanded secondary set of surface points, and the travel times are calculated using the expanded set.

Abstract: Pipeline wall thickness is measured as a function of position using ultrasound propagation. A series of predictive models is used, which define predictions of the ultrasound response signals as a function of different sets of parameters. The different sets that are determine of position dependent ultrasound speed at different sound frequencies and different spatial resolution. Successive iterative fitting process are executed, each fitting a combination of values of a successive set of parameters to the detected ultrasound response signals according to a respective model, using the values fitted values from the previous fitting process to initialize the next set of parameters for iterative fitting.

Abstract: A fluid flow meter is described that uses thermal tracers to measure flow speed. For fluid flowing through a conduit, the fluid is heated at a heating location in the conduit with a time-dependent heating strength. A speed of sound in fluid flowing in the conduit is measured at multiple sensing locations downstream from said heating location. The flow speed of the fluid is determined from a delay with which the time dependence is detected in the sound speeds measured at the sensing locations. A frequency of the variation of heating strength that is used to determine the flow speed is selected automatically based on the flow speed and/or other circumstances.

Abstract: A method of modelling a surface of an object by using ultrasonic waves transmitted along the surface comprises the steps of: transmitting the ultrasonic waves along paths along the surface, and determining travel times of the ultrasonic waves along the paths. At least some of the ultrasonic waves exhibit an S0 mode and have a frequency-dependent velocity. This velocity (c) is relatively high for frequencies up to a first bending point (BP1), decreasing relatively rapidly for frequencies between the first bending point (BP1) and a second bending point (BP2), and relatively low for frequencies beyond the second bending point (BP2). The ultrasonic waves have a frequency range which lies at or below the first bending point (BP1).

Abstract: A method of producing a temperature model of a surface of an object using ultrasonic transducers comprises the steps of iteratively adjusting a temperature model by using measured travel times of ultrasonic waves and their predictions model-based. The ultrasonic waves used for producing the temperature model are preferably substantially non-dispersive ultrasonic waves. The method may further involve a height model of the surface, which height model is produced using substantially dispersive ultrasonic waves and is corrected by using the temperature model.

Abstract: A system for detecting defects in a pipe wall, comprises an ultrasonic transducer which is arranged for emitting, via an exit opening, ultrasonic signals from the interior of the pipe towards its wall and for receiving, via an entrance opening, backscattered signals from the wall. The system is arranged to emit and receive a multitude of signals having their main directions within a plane mainly perpendicular to the pipe axis. The openings are configured to make the ultrasonic transmission signal diverge and/or to receive back signals from a diverging range of angles over a large area of the pipe wall, by using openings with a diameter with magnitude of the wavelength of the ultrasonic signals. Sets of emitted and backscattered signals for different emission and reception positions are processed, in processing means, to form an image based on transmission times between emission and reception of backscattered signals.

Abstract: Fluid flows through a conduit. To measure flow speed the fluid is heated at a heating location in the conduit with a time-dependent heating strength. A speed of sound in fluid flowing in the conduit is measured at a plurality of sensing locations downstream from said heating location. The flow speed of the fluid is determined from a delay with which the time dependence is detected in the sound speeds measured at said sensing locations. In an embodiment a frequency of the variation of heating strength that is used to determine the flow speed is selected automatically dependent on the flow speed and/or other circumstances.

Abstract: In an immersion lithography apparatus, ultrasonic waves are used to atomize liquid on a surface of the substrate.

Abstract: In an immersion lithography apparatus, ultrasonic waves are used to atomize liquid on a surface of the substrate.

Abstract: A method of modelling a surface (3) of an object (2) using ultrasonic transducers (4, 5) mounted on the surface comprises the steps of: providing a model of the surface, the model comprising a primary set of surface points indicative of the height of the surface, transmitting pulsed waves from a first transducer (4) to one or more second transducers (5), the first transducer and each second transducer defining a respective path along the surface, measuring travel times of the pulsed waves along each path, calculating travel times based on the model of the surface, adjusting the model of the surface in response to any discrepancies between the measured travel times and the calculated travel times, and repeating the steps of transmitting, measuring, calculating and adjusting until the discrepancies are smaller than a predetermined threshold.

Abstract: Fluid flows through a conduit. To measure flow speed the fluid is heated at a heating location in the conduit with a time-dependent heating strength. A speed of sound in fluid flowing in the conduit is measured at a plurality of sensing locations downstream from said heating location. The flow speed of the fluid is determined from a delay with which the time dependence is detected in the sound speeds measured at said sensing locations. In an embodiment a frequency of the variation of heating strength that is used to determine the flow speed is selected automatically dependent on the flow speed and/or other circumstances.

Abstract: On the basis of a series of reflection measurements on a liquid, parameters are calculated which describe a particle size distribution of particles in the liquid. In each reflection measurement, a signal beam is generated in the liquid and a value of a property such as the amplitude of a reflection on a particle in the signal beam is measured. Using maximum likelihood estimation, the parameters of the particle size distribution are estimated, on the basis of an expression for a probability of the measured values as a function of the measured values. The expression used contains a first factor for the probability of a reflection measurement of which a reflection with the measured value forms part, corrected with a second factor for the probability that there is not also a reflection with a dominating value of the property, which would mask the measured values, forming part of the reflection measurement.

Abstract: In an immersion lithography apparatus, ultrasonic waves are used to atomize liquid on a surface of the substrate.

Abstract: In an immersion lithography apparatus, ultrasonic waves are used to atomize liquid on a surface of the substrate.

Abstract: A method for characterizing a suspension with particles floating therein, which method comprises the steps of generating an acoustic actuation signal and registering an acoustic reflected signal. Further, a first dataset is calculated on the basis of the reflected signal, the dataset containing information which represents an autocorrelation function as a function of time of the reflected signal. Thereupon, first datasets are combined into a second, cumulated dataset, which represents a sum of the autocorrelation functions which correspond with the first datasets. Finally, a representation of a particle size distribution is determined by solving this representation from an expression for the second, cumulated dataset in terms of the representation of a particle size distribution.