Systems and methods are provided to control operational parameter(s) of a spin-on process based on a localized fluid velocity of a processing liquid dispensed onto a surface of a spinning semiconductor substrate. In the present disclosure, a perturbation is introduced within a processing liquid dispensed onto the spinning semiconductor substrate. Movement of the perturbation is tracked over time, as the perturbation flows along with the processing liquid across the spinning substrate surface, to determine a localized fluid velocity of the processing liquid at one or more radial positions on the substrate surface. The localized fluid velocity is then used to control one or more operational parameters of a spin-on process.

The disclosure relates to a reflection unit applied to an ultrasonic anemometer and used to reflect ultrasonic waves from a transmitter, wherein the reflected ultrasonic waves are received by a receiver. The reflection unit comprises a reflection plate and further comprises a mesh cover layer structure covering on the upper surface of the reflection plate. In an embodiment of the present disclosure, the mesh cover layer is provided on the reflection plate, so that the raindrops/water droplets falling on the reflection unit can be quickly scattered on the surface of the reflection unit, thereby eliminating the irregular shape and high liquid accumulation formed on the surface of the reflection unit, ensuring the accuracy of ultrasonic anemometer measurements in wind and rain conditions.

A method for determining a flow speed of a liquid in a fluid conduit is provided. During a signal-generating phase, an impulse signal is applied to a first ultrasonic transducer. A response signal is then received at a second ultrasonic transducer. A measuring signal is later derived from the response signal, wherein the derivation comprises reversing a signal portion with respect to time. During a measurement phase, a liquid moves with respect to the fluid conduit. The measuring signal is then applied to one of the two transducers and a response signal of the measuring signal is measured at the other transducer. A flow speed is derived from the response signal of the measuring signal.

A gases humidification system includes a measuring chamber and a mixing chamber. The mixing chamber has one or more mixing elements that improve a mixing of gases before reaching the measuring chamber. Ultrasonic sensing is used to measure gases properties or characteristics within the measuring chamber. A baffle or a vane may be used to control and direct the gases flow through the mixing chamber as the gases flow moves into the measuring chamber.

A method for determining waveguide temperature for at least one waveguide of a transceiver utilized for generating a temperature map. The transceiver generates an acoustic signal that travels through a measurement space in a hot gas flow path defined by a wall such as in a combustor. The method includes calculating a total time of flight for the acoustic signal and subtracting a waveguide travel time from the total time of flight to obtain a measurement space travel time. A temperature map is calculated based on the measurement space travel time. An estimated wall temperature is obtained from the temperature map. An estimated waveguide temperature is then calculated based on the estimated wall temperature wherein the estimated waveguide temperature is determined without the use of a temperature sensing device.

A method of determining a measure of wave speed or intensity in a fluid conduit uses ultrasound measurements to determine the conduit diameter and fluid velocity in a volume element, each as a function of time, and each at a same longitudinal position of the conduit. The ultrasound measurement to determine fluid velocity is effected by tracking objects within the fluid flow in successive frames sampling the volume element, and obtaining displacement vectors for the objects. A wave speed may be determined from a ratio of the change in fluid velocity at the longitudinal position as a function of time and the change in a logarithmic function of the conduit diameter as a function of time. A measure of wave intensity may be determined as a function of change in determined conduit diameter and corresponding change in fluid velocity.

A transducer system. The system comprises a transducer and circuitry for applying an excitation waveform to excite the transducer during an excitation period. The circuitry for applying has: (i) circuitry for applying a first waveform at a first frequency; and (ii) circuitry for applying a second waveform at a second frequency differing from the first frequency.

An ultrasonic airspeed and direction sensor system comprising an ultrasonic sensor array including an elongate base member for mounting to a vehicle, such as a helicopter, so as to extend outwardly from the vehicle. A number of radially extending support members are connected to the base member. The support members carry ultrasonic transducers arranged to define at least four bidirectional ultrasonic paths between respective pairs of the transducers, the ultrasonic paths being arranged into at least three non-coplanar sets. A processing system monitors the passage of ultrasonic signals along the paths to generate corresponding time of flight data, making a weighted selection containing at least one path from each of at least three sets, and processing the time of flight data for the selected paths, proportionate to the determined weighting, to generate airspeed and direction information.

Techniques for a chamber, such as gas turbine engine (100), surrounding a heated fluid include a sensor (150) mounted in a first wall (228b, 229b) of the chamber to detect phenomenon inside the chamber and a processor (702). The processor is in electrical communication with the sensor and is configured to receive first data, determine a first temperature of the first wall, determine a current path length, determine properties of the fluid flow, and operate a device based on the properties. First data indicates a value of the phenomenon along a path between the first wall and a different wall of the chamber. The current path length (268b) is based on a nominal path length (268a) and thermal expansion of the first wall due to the first temperature. The property of fluid flow in the chamber is based on the first data and the current path length.

A method for determining a flow speed of a liquid in a fluid conduit is provided. During a signal-generating phase, an impulse signal is applied to a first ultrasonic transducer. A response signal is then received at a second ultrasonic transducer. A measuring signal is later derived from the response signal, wherein the derivation comprises reversing a signal portion with respect to time. During a measurement phase, a liquid moves with respect to the fluid conduit. The measuring signal is then applied to one of the two transducers and a response signal of the measuring signal is measured at the other transducer. A flow speed is derived from the response signal of the measuring signal.