Various embodiments provide dye-doped polystyrene microspheres generated using dispersion polymerization. Polystyrene microspheres may be doped with fluorescent dyes, such as xanthene derivatives including Kiton Red 620 (KR620), using dispersion polymerization. Certain functionalities, such as sodium styrene sulfonate, may be used to shift the equilibrium distribution of dye molecules to favor incorporation of the dye into the particles. Polyelectrolyte materials, such as poly(diallyldimethyl ammnonium chloride), PolyDADMAC, may be used to electrostatically trap and bind dye molecules within the particles. A buffer may be used to stabilize the pH change of the solution during dye-doped polystyrene microsphere generation and the buffer may be selected depending on the pKa of the dye being incorporated. The various embodiments may provide dye-doped polystyrene microspheres, such as KR620-doped polystyrene microspheres that are non-toxic and non-carcinogenic. These non-toxic and non-carcinogenic dye-doped polystyrene microspheres may be suitable for use in wind tunnel testing.

Provided are a particle image velocimetry and a method of controlling the particle image velocimetry. The particle image velocimetry includes a light source unit including two or more light sources that generate lights of different colors, wherein each of the light sources irradiates tracking particles in a flow field with a predetermined time difference; a camera that captures an image of the tracking particles; a controller that calculates migration distances of the tracking particles by splitting an image of the tracking particles captured by using the camera, into an image of each color, and calculates a velocity of the flow field by using the time difference at which the light of each of the light sources is irradiated and the migration distances of the tracking particles; and a display unit that receives velocity information of the flow field from the controller to display the velocity information.

Provided are a particle image velocimetry and a method of controlling the particle image velocimetry. The particle image velocimetry includes a light source unit including two or more light sources that generate lights of different colors, wherein each of the light sources irradiates tracking particles in a flow field with a predetermined time difference; a camera that captures an image of the tracking particles; a controller that calculates migration distances of the tracking particles by splitting an image of the tracking particles captured by using the camera, into an image of each color, and calculates a velocity of the flow field by using the time difference at which the light of each of the light sources is irradiated and the migration distances of the tracking particles; and a display unit that receives velocity information of the flow field from the controller to display the velocity information.

A method includes irradiating a target droplet in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with light from a droplet illumination module. Light reflected and/or scattered by the target droplet is detected. Particle image velocimetry is performed to monitor one or more flow parameters inside the extreme ultraviolet light source.

A method includes irradiating a target droplet in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with light from a droplet illumination module. Light reflected and/or scattered by the target droplet is detected. Particle image velocimetry is performed to monitor one or more flow parameters inside the extreme ultraviolet light source.

Radiation curable compositions for additive fabrication processes, the components cured therefrom, and their use in particle image velocimetry testing methods are described and claimed herein. Such compositions include compounds which induce free-radical polymerization, optionally compounds which induce cationic polymerization, a filler constituent, and a light absorbing component, wherein the compositions are configured to possess certain absorbance values at wavelengths commonly utilized in particle image velocimetry testing. In another embodiment, the compositions include a fluoroantimony-modified compound. Such compositions may be used in particle imaging velocimetry testing methods, wherein the test object utilized is created via additive fabrication and is of a substantially homogeneous construction.

Radiation curable compositions for additive fabrication processes, the components cured therefrom, and their use in particle image velocimetry testing methods are described and claimed herein. Such compositions include compounds which induce free-radical polymerization, optionally compounds which induce cationic polymerization, a filler constituent, and a light absorbing component, wherein the compositions are configured to possess certain absorbance values at wavelengths commonly utilized in particle image velocimetry testing. In another embodiment, the compositions include a fluoroantimony-modified compound. Such compositions may be used in particle imaging velocimetry testing methods, wherein the test object utilized is created via additive fabrication and is of a substantially homogeneous construction.

A measuring method enabling simple and accurate measurement of a flow velocity distribution in a flow field inside a flow passage of an optical cell and a particle size-measuring method using the measuring method are provided. In a device including a laser light irradiation unit irradiating laser light at a wavelength into the flow passage, a camera capturing an inside of the flow passage to which the laser light is irradiated, and an analysis unit obtaining a flow velocity distribution in the flow field from at least a plurality of images captured in a light exposure time at each predetermined time interval t, providing a tracer particle of a smaller size than the wavelength of the laser light into the flow passage and capturing a bright spot attributed to the light scattering from tracer particles by the camera, and obtaining the flow velocity distribution by the analysis unit by obtaining an amount of movement of each tracer particle from movement of the bright spot and correcting a Brownian motion component from a correlation between an average value of variations of the amount of movement and Brownian motion are performed. In addition, obtaining the particle size of a measurement target particle by obtaining a corrected displacement obtained by removing a movement component of the flow field caused by the flow velocity distribution from a displacement of the measurement target particle is performed.

The invention relates to a method for determining a charge characteristic (K) of electrical charges of particles (16) in a fluid stream comprising the steps (a) directing the fluid stream, which contains particles (16), through a fluid line (20), (b) spatially-resolved determination of a measuring field-less particle velocity (v) in a measurement area without an electrical measuring field, (c) applying an electrical measuring field transverse to the flow direction (S) in the measurement area, (d) spatially-resolved determination of a midfield particle velocity (v.sub.E) in the measurement area and (e) determining the at least one charge characteristic (K), which denotes an electrostatic charge of the particles (16), from the spatially-resolved particle velocities.

Systems and methods are provided for making in-situ measurements of the sea bed 3 component fluid velocity field and sediment motion across a range of real ocean conditions using particle image velocimetry (PIV). A PIV system in accordance with an embodiment of the present disclosure can include a camera to capture images of the particles in motion, a laser to generate a laser sheet for illuminating the particles, and a synchronizer to act as an external trigger for the laser and the camera.