Unformatted text preview: channel. We apply both a pressure and a mystifying body field force (MBFF - a force that is not physical in nature but one that will make the math easier for you to solve). This MBFF is a volumetric body force equal to ρ e Bu , where e is the volumetric charge density, B is a magnetic field in Teslas, and u is a constant velocity in the y direction. What would the nanochannel velocity profile be (v x as a function of y)? Question 4: Two molecules with different mobilities and charges (mobility A = 4.3 x 10-13 , charge A = -2, and mobility B = 2.1 x 10-13 , charge B = -4) are traveling down a 200nm x 200nm square cross-sectional area (and 10mm long) nanochannel that has a nondimensional zeta potential =1 and 10 nm electric double layer thickness. a. What are the approximate time scales for diffusion, electromigration, and advection? b. What if the channel was 20um x 20um? c. Which molecule would travel faster in each case?...
View Full Document
- Spring '08
- Magnetic Field, Electric charge, Fundamental physics concepts, Van der Waals, controllable nanomechanical memory, Nanomechanical Memory element