Stroboscopic image

A classic self-light stroboscopic image of a premixed flame undergoing a tulip inversion in a closed tube. There is an interval of 4.1 ms between the images of a water vapor saturated CO/Oj flame arranged to have a flame speed comparable with that of a stoichiometric methane/air flame. The tube is 2.5 cm in diameter and 20.3 cm long. (Adapted from Ellis, O.C. de C. and Wheeler, R.V., /. Chem. Soc., 2,3215,1928.)... 

Franz von Uchatius (1811-1881), who used a magic lantern to cast stroboscopic images onto a wall. These were essentially cartoons, since they were animated drawings. 

Fig. 5 Stroboscopic images of microcapsule formation via midair collision between two component liquids (scale bar = 100 pm) (A) and bright-field microscope images of microcapsules (B). The left and streams are 0.25% alginate solution and 4% PLGA solution, respectively. The nozzle orifice diameter d = 60 pm volumetric flow rate Q = 0.6 ml/min and forcing frequency / = 10.6 kHz. (From Ref...

Before we finish this subsection, we would like to discuss the practical limitations of the Poincare sections, which require Lagrangian particle tracking for extended times. In reality. Fig. 2 presents stroboscopic images of the same four particles passing through thousands of mixing block boundaries. This has two basic implications. First, numerical calculation of the Poincare sections requires either analytical solutions or high-order accurate discretizations of the velocity field. Otherwise, the results may suffer from numerical diffusion and dispersion errors, and the KAM boundaries may not be identified accurately. Second, it is experimentally difficult, if not impossible, to track particles (in three-dimensions) beyond a certain distance allowed by the field of view of the microscopy technique. Despite these... 

A stroboscopic image of drops being ejected is shown in Figure 6.12. The nozzle is indicated by a dashed line. The reflection of the drop that is being ejected can be seen in the nozzle plate to the left in the figure. Drops that have been ejected can be seen on the right. 

Fig. 9.2.3. A stroboscopic image of the eye of the vortex core precessing along the cyclone wall...

For periodic flow especially in vibrated systems, stroboscopic images are useful [6-10,12,13,34,66,146,147,201-204]. Stroboscopic imaging is especially useful when the images can be phase synchronized as well [6-10,34,66,201-204]. With phase synchronization, the frequency of the strobe is locked to a phase reference, which can be adjusted to view the motion at any phase relative to the reference. 

A rather ideal droplet formation of ethylene glycol is shown as a sequence of stroboscopic images in Figure 9. First, a liquid column of ink is ejected from the nozzle, which will immediately adapt to a spherical shape due to the surface tension of the liquid. The liquid remains attached to the nozzle by a fluid filament, which can form a secondary filament, shown in... 

Figure 17(b) shows the typical droplet formation for a 2 wt.% PS solution in butyl acetate (i) and a 2 wt.% PS solution in toluene (ii) as stroboscopic images, where the time between each droplet is 100 ps. It can be seen that after approximately four droplets in time, the droplet has reached a steady shape, thus equilibrium. Hence, printing should be performed at least from a height where the final equilibrium velocity has been reached. In the experiments, the first data point that was recorded with the minimal printing height was, therefore, neglected. 

Viscosity tj) is calculated using the Staudinger equation, whereas surface tension (y), density (p), and contact angle (0) are measured. The droplet s velocity (i and in-flight diameter (do) are calculated irom the stroboscopic images. From these values, the Reynolds (Re), Weber (We), and Z-numbets were calculated. 

Fig. 8.7.2 The 48-pulse sequence used for imaging with phase and frequency encoding. For second averaging the phases of the rf pulses are shifted in small increments (phase shifter). The signal is observed stroboscopically during (2- Adapted from [Corl3] with permission from Wiley-VCH.

The Multichannel ("Stroboscopic") Optical Spectrum Analyser (MOSA) allows us to carry out spatial Fourier analysis of the images of a ruffled water surface. One can show (see, Appendix) that the frequency spectrum s(co) = < i cof > (<...> denotes statistical averaging) of the MOSA signal i t) can be written in the form... 

The detection zone can be interrogated by a beam ID scanning approach during rotation which can be extended by a radial translation stage to 2D. Also, imaging systems have been employed which usually require low-exposure time image capture in a stroboscopic fashion or even stopping of the disc. 

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