Conférence de Chen-li SUN (National Taiwan University)


 AHLeGall    15/06/2017 : 21:55

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Le jeudi 15 juin 2017 à 11h00, ans la Salle des Thèses (Bât.2A, Université Rennes 1, Campus Beaulieu) Chen-li SUN propose un séminaire intitulé "On the locomotion of planktonic micro-organisms in a microfluidic environment"

Le jeudi 15 juin 2017 à 11h00, ans la Salle des Thèses (Bât.2A, Université Rennes 1, Campus Beaulieu) Chen-li SUN propose un séminaire intitulé "On the locomotion of planktonic micro-organisms in a microfluidic environment"

Abstract
Planktonic micro-organisms play an important role in marine ecology, fishery, and the ocean
carbon cycle. As the foundation of the oceanic food chain, phytoplankton and zooplankton form
a complex food web, and their trophic interaction is vital to the prosperity of other marine life.
In this talk, I will demonstrate how microfluidic devices can be employed to gain a better
understanding of marine ecosystem in a single-cell level.
Focusing on studying the locomotion of plankton K. veneficum (CCMP426), we design a
microcavity device to investigate the effects of different microflow conditions: stationary f/2-Si
medium, steady flow, and oscillatory flow. After measuring the local flow field, we are able to
determine the absolute and relative velocities of individual plankton cells, from which their
rheotaxis can be derived. The probability density function, the expected value and the standard
deviation are calculated in order to statistically represent the locomotion of the planktonic
community. The experimental results show that when the plankton reside in stationary and
homogeneous nutrient medium, the swimming velocity and the acceleration are 52.7±43.5 μm s-1
and 878±820 μm s-2, respectively. In addition, K. veneficum is capable of maneuvering in a flow
speed up to 150 μm s-1. Once the current is too strong, their locomotion is dominated by the flow.
Under the condition of oscillatory flow, K. veneficum exhibits positive rheotaxis. In the strong
flow field region, planktonic cells can not directly cross the streamlines. Rather, they tend to cut
through streamlines with small angle in order to reach the weak flow field region. The outcome
of this study helps us clarify the interaction between the behavior of plankton and the
microfluidic environment.


Biography
Chen-li Sun is Professor of Mechanical Engineering at National Taiwan University (NTU). She
teaches in the areas of thermodynamics, heat transfer, energy engineering, two-phase flow, and
thermal management for electronic devices. She is Visiting Professor at l’École normale
supérieure de Rennes (Summer 2017) and l’Université Paris-Sud (Winter 2016). Prior to joining
NTU, she was on the faculty of National Taiwan University of Science and Technology from
2003 to 2011. Prof. Sun received her B.S. degree from National Central University, Taiwan in
1994, M.S. from Stanford University in 1996, and Ph.D. from the University of California at
Berkeley in 2002, all in Mechanical Engineering. In 2002-03, she was a postdoctoral researcher
for Prof. Al P. Pisano in the Berkeley Sensor and Actuator Center (BSAC). Prof. Sun is the 2012
recipient of the Ta-You Wu Memorial Award, which recognizes young Taiwanese PIs dedicated
to long-term outstanding research work. She is also the 2014 recipient of the Distinguished
Young Scholar Award from the Society of Theoretical and Applied Mechanics. Dr. Sun’s research
interest focuses on near-interface microscale transport phenomena and phase-change heat
transfer in energy systems. Specifically, she is interested in exploring innovative measurement
techniques for studying microscale transport in microfluidics.

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Contacts OSUR
Céline Thébault (IPR) / @