Light sheet visualization

For examination of mixing behavior, light sheet visualization is important, particularly in multiple-impeller systems, to help the experimentahst think about suitable points of addition to study a mixing system, possible choice of feed location, and an initial estimate of suitable probe locations for mixing time experiments. Further tests should be performed to provide more detailed information on suitable choices of probe location. 

Figure 8.8 Skimming, Interference Flow and Isolated Roughness Flow visualizations using Laser light sheet (Chang and Meroney, 2003 [111, 112]).

A thin light sheet is shone into an area of interest and enables the flow in that area to be visualized. 

Keller, P.J., Ahrens, M.B. Visualizing Whole-Brain Activity and Development at the Single-Cell Level Using Light-Sheet Microscopy. Neuron 85(3), 462-483 (2015)... 

At visualization of flows, the measurement depth and field of view define the measurement volume. The extension of the measurement volume in the direction of the camera is the measurement depth. If volume illumination is used, the measurement depth is dependent on the depth of field of the camera optics. Otherwise, when illuminating with a light sheet, the measurement depth is... 

FIG. 4. Visualization of streamwise vortices by laser light sheet technique. 

Laser Gas Light source for optical fiber probe Sheet lighting for visualization IR laser for contact-free heating (CO2 laser) Horio et al. (1988) Horio and Kuroki (1994) Yamada et al. (1996)... 

Liquid lens showing electrode embedded at each contact circle. Photo on right was taken with thin laser light sheet illuminating liquid lens from above. For visualization, fluorescein dye at 4 ppm concentration was dissolved in double-distilled water. Illumination was from a 488 nm line of an argon ion laser. Yellow fQter was used on the camera lens. (Source Lopez, C.A., C.C. Lee, and A.H. Hirsa. 2005. Applied Physics Letters, 87(13), 134102. With permission.)... 

The small length scales involved in micro- and nanofluidics do not allow for the convenient production of a light sheet to visualize distinct planes of fluid. Instead, imaging was typically limited to volumetric flood illumination as the only visualization technique, which used the depth of focus (DOF) of the microscope objective to designate distinct fluid planes [3]. The DOF is generally described by... 

Yang, W. J. 2001. Handbook of Flow Visualization, 2nd ed. New York Taylor Francis. Covers techniques used to visualize flow in liquids and gasses. Includes both underlying theory and experimental applications. Techniques presented include Schlieren, shadowgraph, speckle, interferometry, light sheet, and plasma fluorescence. Numerous applications are given in subsequent chapters medical, aerospace, wind tunnels, turbines, and indoor airflow. 

In order to visualize the mixing or penetration, Rhodamin B with a concentration of 200 mg/kg was added to liquid feed of one droplet train. Activated by a laser beam the droplets glow with fluorescent light. The laser light sheet was created by a LEXEL laser 3500 with 5 W power (wavelength = 475 nm), and its width was expanded to 15 mm at the collision point. The thickness of the sheet was around 2 mm. 

Fig. 7.1 The tetramer of eco bound to a serine protease. Visualized as a cartoon of the canonical protease and eco interaction (a), and (b), as two views of the three dimensional solution of D102N trypsin in complex with eco [3]. Each eco molecule has three protein-protein interaction surfaces. The C-terminus forms an anti-parallel p ribbon to complete the ecotin dimer interface. The 80 s and 50 s loops form the primary binding site by interacting with the protease at the active site cleft in a sub-strate-like y -sheet conformation. The 60 s and lOO s loops of eco form the secondary binding site by interacting with the C-termi-nal a-helix of the protease. Note that each eco molecule contacts both of the protease molecules. Two eco molecules (black and medium grey) form a pair of interactions each with two protease molecules (light grey). The catalytic triad residues Ser-195, Asp-102 and His-57 are in black ball and stick representation. This figure was made with Molscript [37] and Raster 3D [38].

---