practice_quiz_2

practice_quiz_2 - channel. We apply both a pressure and a...

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ME 125NT Introduction to Nanotechnology P r a c t i c e Q u i z # 2 Question 1: Short Answers a. What are the benefits of nanomechanical systems? b. What are fullerenes? c. What are the properties of nanomaterial that makes it different than the bulk material they come from? d. What are the three different types of Van Der Waals bonds? e. What are zeolites? Question 2: Nanomechanical Memory element Badzey et al (see attached paper) built a controllable nanomechanical memory element. a. What is the drive frequency they must use to get the bi-stable performance? b. What is the resonant frequency? c. From this, what is the spring constant of the beam (assume this beam has the same properties as silicon) d. The authors state a relation for frequency depending on Length and thickness. According to this relation, what would the resonant frequency be is the beanm were only 500 nm long? And what would the spring constant be? Question 3: Imagine a nanometer scale fluidic channel with a ferromagnetic fluid inside the
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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 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?...
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This note was uploaded on 08/06/2008 for the course ME 125 taught by Professor Pennathur during the Spring '08 term at UCSB.

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