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Michelle E. Staben |
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Email address: |
michelle.staben at colorado.edu (replace at with @) |
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Undergraduate Institution: |
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Undergraduate Degree: |
B.S. in Chemical Engineering |
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Graduate Degree: |
Ph.D. in Chemical Engineering |
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On graduate school: |
"Graduate
school is as much about discovering truth in science and culture as it is about
discovering truth in ourselves." -Jorge Cham, the creator of "Piled Higher and Deeper”
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Personal
Information: |
How I ended up doing my graduate work at CU |
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My undergraduate education was at North Carolina State University. I ended up there because in high school, I was pretty good at math and science and was directed to an engineering career. I chose chemical engineering because I was interested in the myriad ways that it could be used to help clean up the environment. While I was at NCSU, I immersed myself in a ton of extracurricular activities, participating in every intramural sport (except swimming) and running student groups such as Engineers’ Council and the NCSU chapter of Omega Chi Epsilon (which some friends of mine and I co-founded). The summer after my sophomore year, I was an REU student at the University of Iowa, Iowa City, and spent the summer conducting membrane science research. That experience started me thinking about attending graduate school to pursue a career in research. I graduated from NCSU in May of 1999 and spent that summer conducting research in the Department of Food Science at NCSU. In the fall, I moved 2/3rds of the way across the country to CU to pursue my Ph.D. I chose CU for its strong emphasis on biotechnology and environmental research and for the pristine natural beauty of Boulder. (I just started skiing in my last year of college and liked the idea of living near the slopes for a few years of my life. It also gives my friends a reason to come visit me.) Life in Boulder was great. I successfully defended my Ph.D. in May. Officially I graduated in August, but rather than doing dissertation research (which was completed in the spring), I spent the summer working as an Instructor in the Multicultural Engineering Program’s Summer Bridge Program, a five-week summer course to introduce incoming minority engineering students to the rigors of an engineering education. This program was a good fit with my interests in encouraging the participation of diverse students in engineering careers. I spent much of my free time in graduate school (not that there’s that much free time) skiing and playing Ultimate frisbee. I played on the women’s team here from 1999-2003, when my college eligibility ran out. My last two years we were 3rd in the nation. I got a season pass to the Vail resorts every year to work on my skiing. For summer sports, I’m into hiking and mountain biking and ultimate (of course). This past fall, I returned to Raleigh, NC, to be with my fiancé, LJ, who works for Cisco Systems, traveling the world as a technical marketing engineer. At this point in my career, I’m excited about the chance to apply the skills I learned in graduate school to a rewarding research career, probably in biotechnology or pharmaceuticals. I hope to have the chance to work on interesting problems and then present the results, both in oral and written forms, to various audiences, e.g., co-workers and/or conference attendees, depending on what type of job I find. |
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Dissertation Project Title: |
Low-Reynolds-Number Particle Transport in Narrow Channels for Microfluidics and Other Applications |
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Dissertation Research Overview: |
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Particle transport in low-Reynolds-number flows occurs in many chemical engineering and biological processes, such as suspensions processing, flow cytometry, sedimentation, membrane separations, polymer processing, and blood flow. The Reynolds number compares the relative importance of inertia and viscous forces; in low-Reynolds-number flows, viscous drag dominates over inertia. Interest in low-Reynolds-number transport has only increased with the explosion of research in the relatively new field of microfluidics, which is generally defined as the transport of fluids in microchannels with cross-sectional dimensions on the order of tens to hundreds of microns and lengths of centimeters. Microfluidic devices are being explored for numerous applications, from DNA analysis to biosensors for the detection of pathogens to combinatorial chemistry of potential pharmacological agents. A global goal of microfluidics research is to obtain a disposable, single-use, portable device that would be easy to use and would contain all the necessary unit operations to perform a desired assay. However, a better understanding of the fabrication and functioning of microfluidic devices must be obtained before this goal can be achieved. Our department is now expanding into the broad research area of microfluidics, which is being researched by a number of graduate students. The overall goals include fabrication of polymeric microfluidic devices using photopolymerization techniques, which allow creation of the devices in a variety of geometries and living radical polymerization techniques for surface modifications, where a living radical is a polymer unit with an end that can be reinitiated after the initial reaction to form the polymer is done. Various unit operations, such as fluid flow, filtration, separation, mixing, and reaction, are being designed and fabricated. Experimental measurements of the fluid flow in the devices and connecting channels are being obtained and compared to various simulations developed in our department. The unit operations can then be combined into a single system to perform a complicated biological analysis, such as an ELISA assay. Our department had a three-year DARPA grant (which ended in January 2005) for polymeric microfluidic devices. The overall project goals of the microfluidics work in this department are to: ·
Design and
fabricate polymeric microfluidic devices using living radical
photopolymerization, ·
Perform
biofluidic transport modeling, characterization, and experimental evaluation
of microfluidic devices, ·
Develop,
demonstrate and characterize molecular recognition and biofluidic interfacing
for selected model applications. A main area of interest in microfluidics research is the transport of particles (e.g., cells in a bioassay) in microfluidic channels. The high surface-area-to-volume ratio of the channels in the devices means that the influence of the surface properties on transport processes is much greater than in macroscale processes. Low-Reynolds-number flows preclude turbulence as a mixing phenomenon, so that mixing of suspensions and fluids (e.g., a sample and reagents for chemical reaction) must be performed using a mixing unit operation or by diffusion across the channel. Channels in the device usually have large-aspect-ratio cross sections, so transport phenomena can be successfully modeled with a parallel-plate model. Fluids and particles are pumped through the devices using pressure-driven methods, such as hydrogel micropumps (yielding Poiseuille flow), or by application of an electric field (yielding electrokinetic flows). In my work, I have focused on pressure-driven flows. Understanding low-Reynolds-number fluid mechanics is motivated by a need for both a fundamental picture of the fluid-mechanics phenomena and by real-world applications, such as microfluidics. The overall objective of my project is to gain a quantitative understanding of the transport of particles in low-Reynolds-number flows in large-aspect-ratio channels, with specific applications to Poiseuille flows and inclined settling in quiescent fluids. My dissertation confronts this problem from both theoretical and experimental standpoints, with a numerical simulation and related analytics developed to describe the transport of spherical and spheroidal particles and experimental verification of the model at low Reynolds number. Of particular interest are narrow channels, in which the smallest dimension of the channel (i.e., height or width) is not much larger than the particle size. The specific goals of my research are: 1. Development of a quasi-steady boundary-integral simulation of the Poiseuille transport of neutrally-buoyant spherical and spheroidal particles between two infinite plane walls, 2. Extension of the model to close spacings of the particle from the wall(s) for neutrally-buoyant spherical and spheroidal particles, 3. Videomicroscopy of neutrally-buoyant spherical particle transport in a large-aspect-ratio microchannel to experimentally verify results from the simulation for the translational velocity for a range of sphere sizes in Poiseuille flow and to ascertain the effects of entrance geometry on particle location distribution across the narrow dimension of the microchannel, 4. Utilization of the quasi-steady boundary-integral simulation as the basis for dynamic simulations of neutrally-buoyant spheroidal particle transport in Poiseuille flow between two parallel plane walls, 5. Application of quasi-steady boundary-integral results for the lubrication formulations for a sphere between two plane walls to the dynamic simulation of a sphere transported by a Poiseuille flow in a horizontal channel or by gravity-induced settling in a quiescent fluid in an inclined channel, 6. Theoretical analysis of contact forces on the motion of microscopically-rough heavy spheres in a horizontal-channel Poiseuille flow or in a quiescent fluid in an inclined channel, and 7. Experimental verification of the contact-force model for heavy spheres in a Poiseuille flow in a horizontal channel or in a quiescent fluid in an inclined channel.
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Link to pdf of dissertation |
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Publications: |
Kodzwa,
M.G., M.E. Staben, and D.G. Rethwisch, "Photoresponsive control of
ion-exchange in leucohydroxide containing hydrogel membranes," Journal
of Membrane Science, 158 (1-2), 85-92 (1999). Staben, M.E., A.Z.
Zinchenko, and R.H. Davis, “Motion of a particle between two parallel plane
walls in low-Reynolds-number Poiseuille flow,” Physics of Fluids, 15,
1711-1733 (2003). Staben, M.E., and R.H. Davis, “Particle transport in Poiseuille flow in narrow channels”, International Journal of Multiphase Flow (in press). Staben, M.E., A.Z. Zinchenko, and R.H. Davis, “Dynamic simulation of a spheroid between two parallel plane walls in low-Reynolds-number Poiseuille flow”, Journal of Fluid Mechanics (accepted). Staben, M.E., K.P. Galvin, and R.H. Davis, “ Low-Reynolds-number motion of a heavy sphere between two parallel plane walls”, Chemical Engineering Science (under review). |
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Presentations: |
Posters: “Polymer Based Microfluidic Devices for Biological
Applications,” Gordon Research Conference on Gravitational Effects in
Physicochemical Systems, Colby-Sawyer College, New London, NH, July 8-13,
2001. (Authors: M. E. Staben, K.S.
Anseth, R.H. Davis) “Living Radical Photopolymerization of 3D Microfluidic
Devices for Biofluidic Transport,” 2002 BioExpo, Fitzsimmons Bioscience Park,
Aurora, CO, December 4, 2002.
(Authors: Christopher Brotherton, Brian Good, Tommy Haraldsson, J.
Brian Hutchison, Sirish Reddy, Robert Sebra, Michelle E. Staben, Kristi S.
Anseth, Christopher N. Bowman, Robert H. Davis) “Biofluidic Transport and Molecular Recognition in Polymeric Microdevices,” DARPA Principal Investigators’ Meeting, Santa Barbara, CA, February 6, 2003. (Authors: Christopher Brotherton, Brian Good, Tommy Haraldsson, Brian Hutchison, Sirish Reddy, Robert Sebra, Michelle Staben, Kristi S. Anseth, Christopher N. Bowman, Robert H. Davis) “Modeling and Experimental Analysis of Particle
Transport in Microfluidic Devices,” 2003 AAAS Annual Meeting, Denver, CO,
February 15, 2003. (Authors: Michelle E. Staben, Brian
T. Good, Alexander Z. Zinchenko, Kristi S. Anseth, Christopher N. Bowman, Robert H. Davis)
“Modeling and Experimental Analysis of Particle Transport in Microfluidic Channels,” Gordon Research Conference on The Physics and Chemistry of Microfluidics, Big Sky Resort, Big Sky, MT, August 24-29, 2003. (Authors: Michelle E. Staben, Alexander Z. Zinchenko, Robert H. Davis, Kristi S. Anseth)
Oral Presentations: “Modeling of Particle Transport in Microfluidic
Devices”, Student Annual Research Symposium, Department of Chemical
Engineering, University of Colorado, Boulder, CO, April 15-16, 2002. (Authors: M.E. Staben, A.Z. Zinchenko,
R.H. Davis) “Modeling of Particle Transport in Narrow Microfluidic
Channels”, Low Reynolds Number Hydrodynamics Session of the 2002 American
Institute of Chemical Engineers Fall Annual Meeting, Indianapolis, IN,
November 3-8, 2002. (Authors: M.E.
Staben, A.Z. Zinchenko, R.H. Davis) “Dynamic Simulation of Particle Transport in Narrow Microfluidic Channels”, Low-Reynolds-Number and Microfluidic Flows Session of the 2003 American Institute of Chemical Engineers Fall Annual Meeting, San Francisco, CA, November 16-21, 2003. (Authors: Michelle E. Staben, Alexander Z. Zinchenko, Robert H. Davis) “Particle Transport in Poiseuille Flow in Narrow Microfluidic Channels”, Microscale Flows Session of the 2004 American Institute of Chemical Engineers Fall Annual Meeting, Austin, TX, November 7-12, 2004. (Authors: Michelle E. Staben, Robert H. Davis) |
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Brief
work summary: |
Research Experience: ·
Graduate research assistant/Ph.D. candidate at the University of
Colorado Dept. of Chemical and Biological Engineering, August 1999-2005 ·
Summer Research Intern at Caliper Technologies, Summer 2000 ·
Research Assistant at NCSU Dept. of Food Science ·
Co-op Student in Process Development at Glaxo Wellcome, Spring 1997,
Fall 1997, Summer 1998 ·
Participant in the NSF Research Experience for Undergraduates Program
at the University of Iowa, Summer 1996 Teaching Experience: ·
Instructor of the Projects Course in the Summer Bridge Program,
Summer 2005 ·
Head Graduate Teaching Assistant (TA) for two ChemE courses, Fall
2000 and Fall 2002 ·
TA/Grader for two ChemE courses, Fall 1998, Spring 1999 ·
College mathematics tutor for courses through third-semester
Calculus, Fall 1996 |
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Selected
awards: |
Graduate: National
fellowships: -
NASA Graduate Student Researchers Program (GSRP) Fellowship, awarded
in 2000, 2003 (for three-year periods) -
National Science Foundation Graduate Research Fellowship, awarded in
2000 (for three-year period) Rresearch-related awards
and grants: Intl. J. Multiph. Flow article listed #1 on “Top
25 Hottest Articles” within the journal for the period April-June 2005 Honorable Mention in
Student Poster Competition at the 2003 Annual Meeting of the American
Association for the Advancement of Science (AAAS), February 15, 2003 Beverly Sears Graduate
Student Grant Award, November 2001, March 2003 Biotechnology and RNA
Technology Small Grant, Colorado RNA Center, November 2000 Other fellowships and
grants: Graduate Assistance in
Areas of National Need (GAANN) Fellowship, 1999-2001, 2002-2003 CSEMS (Computer Science,
Engineering and Math Students) Scholarship, University of Colorado-Boulder,
2001-2002 Chemical Engineering
Excellence Fund Award, Department of Chemical Engineering, February 2001 University Fellowship,
Graduate School, University of Colorado-Boulder, 1999-2000 Undergraduate: Major awards: Finalist for Leader of the
Pack at North Carolina State University (NCSU), Fall 1997: annual award for
leadership, scholarship and service in the campus community John F. Miller Award from
Department of Intramural and Recreational Sports, NCSU, 1997-98 academic
year: award given to a single student each year for exceptional contributions
given to the IM-REC Dept. over the prior four years |
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Volunteer
Work: |
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