Microstreaming

Dorai, R. and Kushner, M.J. (2003) Consequences of unburned hydrocarbons on microstreamer dynamics and chemistry during plasma remediation of NOx using dielectric barrier discharges, J. Phys. D Appl. Phys. 36, 1075-83. 

Cleaning and sweeping of the Ti02 surface due to acoustic microstreaming allows for an access to more active catalyst sites at any given time. 

It has been generally observed that the mechanical effects due to cavitational events are more responsible for the microbial disinfection and the chemical and heat effects play only a supporting role [56]. Microstreaming resulting from stable cavitation has been shown to produce stresses, sufficient to disrupt cell membranes... 

On the other hand stable cavitation (bubbles that oscillate in a regular fashion for many acoustic cycles) induce microstreaming in the surrounding liquid which can also induce stress in any microbiological species present [5]. This type of cavitation may well be important in a range of applications of ultrasound to biotechnology [6]. An important consequence of the fluid micro-convection induced by bubble collapse is a sharp increase in the mass transfer at liquid-solid interfaces. In microbiology there are two zones where this ultrasonic enhancement of mass transfer will be important. The first is at the membrane and/or cellular wall and the second is in the cytosol i. e. the liquid present inside the cell. 

At an appropriate intensity level of ultrasound, intracellular microstreaming has been observed inside animal and plant cells with rotation of organelles and eddying motions in vacuoles of plant cells [9]. These effects can produce an increase in the metabolic functions of the cell that could be of use in both biotechnology and microbiology, especially in the areas of biodegradation and fermentation. 

Microstreaming is an event in which large amounts of vibrational energy are put into a small volume with little heating. Furthermore, microstreaming constitutes an unusual type of fluid flow associated with velocity, temperature, and pressure gradients (Laborde et al., 1998). 

Mixer 10 [M 10] Acoustic Microstreaming Micro Mixer, Version 1... 

Mixer type Acoustic microstreaming micro mixer, version 1 Mixing chamber, version (c) width, length, depth 12 mm,15 mm, 125 pm... 

Figure 1.27 Schematic of flow patterns, being part of acoustic microstreaming, induced by an air bubble resting on a solid wall and actuated by a piezoelectric disk [23]...

Figure 1.28 Photographs showing acoustic microstreaming in a micro chamber (with 300 pm depth and 15 mm diameter) which has four air pockets (300 pm depth and 2 mm diameter) at time (a) 0, (b) 10, (c) 25 and (d) 45 s [23] (by courtesy of RSC).

M 10a] [P 9] By one-bubble microstreaming mixing, the dye completely fills the micro chamber within about 110 s [23]. 

M 11] [P 9] Increasing the peak-to-peak amplitude further enhances mixing. By multiple-bubble microstreaming mixing at 5 kHz and 40 V, the dye completely fills the micro chamber within about 6 s (see Figure 1.29) [24]. Mixing based on pure diffusion in the same volume would have taken about 8 h. 

Liu, R. H., Lenigk, R., Druyor-Sanchez, R. L., Yang, J., Grodzinski, P., Hybridization enhancement using cavitation microstreaming, Anal. Chem. 2003, 75, 1911-1917. 

In fact, depending on particle size, simultaneous microstreaming and microjetting or some other effect can determine the efficiency of US-assisted digestion to a variable extent. 

The efficiency and limitations of US-assisted cleaning have been classified into two different categories [76], One involves enhancing mass transport via acoustic streaming and microstreaming, which accelerates the dissolution of soluble contaminants. The other... 

---