Biomedical Engineering Reference
In-Depth Information
500
µ
m
(a)
Base
Cycle 3
Cycle 2
Indicator
Cycle 1
Re
12
Re
70
Cycle 1
Cycle 2
Cycle 3
(b)
Plate 13 Microfl uidic components. (a) A passive check valve in a multilayer structure of polydimethylsiloxane (PDMS). The upper
schematic shows the valve in the closed position: pressure applied from the right presses the fl exible diaphragm against a post, blocking
fl ow through the hole in the center of the diaphragm. The lower schematic shows the valve in the open position: pressure applied from
the left lifts the diaphragm off the post and allows fl ow through the diaphragm hole. The image on the right shows fl ow of a fl uorescent
fl uid through the valve. (b) The design of this chaotic advection mixer exploits the character of laminar fl ow in a three-dimensional
serpentine channel to mix adjacent streams in a single fl ow. A solution of pH indicator runs adjacent to a stream of basic solution and
reveals the progress of mixing. As the two solutions mix, the indicator becomes red. Mixing is effi cient even at low Reynolds num-
bers. Although the fl ow is laminar, there are weak eddies in the corners [163, 167]. Source: http://www.niherst.gov.tt/scipop/sci-bits/
microfl uidics.htm (see Figure 11.33).
Search WWH ::




Custom Search