From Red Cells to Skiing to Soft Lubrication

 

 

 

Qianhong Wu, Ph.D.  Associate Professor

Director, Cellular Biomechanics and Sports Science Laboratory

Department of Mechanical Engineering

Villanova University, USA

 

Abstract ：Biological scientists have wondered, since the motion of red cells was first observed in capillaries, how a red cell, with an 8µm diameter, can move with so little friction in tightly fitting microvessels, only 5-6 µm in diameter, and survive 105 passages through microcirculation during a typical lifetime of 120 days without being damaged or undergoing hemolysis. Recent studies (Feng and Weinbaum, JFM, 2000; Weinbaum et al., PNAS, 2003; Wu et al., PRL, 2004) attributed this frictionless motion to the dramatically enhanced hydrodynamic lifting force generated inside the endothelial glycocalyx layer (EGL), a soft porous layer that covers the inner surfaces of our capillaries, as a red blood cell glides over it. Lift generation inside highly compressible porous media is a new concept for porous media flow. In this talk, a systematic study of this concept is presented. Its diverse applications, from red cells moving in a tightly fitting capillary, to human skiing or snowboarding, to a next generation high speed train that glides on a soft porous track made of goose down pillow will be discussed as examples. These applications are chosen for their novelty, but the basic concepts could have important application in the design of soft porous bearings with greatly increased lubrication pressures and long life.

 

Brief CV ：Dr. Qianhong Wu is an Associate Professor of Mechanical Engineering at Villanova University. He is the founding director of Villanova Cellular Biomechanics and Sports Science Laboratory (CBMSS). Dr. Wu received his Ph.D. in Mechanical and Biomedical Engineering in 2005, from The City College of The City University of New York & New York Center for Biomedical Engineering, working with Dr. Sheldon Weinbaum who is one of the eight living individuals elected to all three U.S. National Academies (National Academy of Science, Engineering and Institute of Medicine) and the only engineer to have received a Guggenheim Fellowship in cell and molecular biology. Before joining Weinbaum’s group in 1999, Dr. Wu had a B.S. in mechanical engineering from Huazhong University of Science and Technology (HUST), and a M.S. in electrical engineering from the Institute of Electrical Engineering, The Chinese Academy of Sciences. In August 2005, Dr. Wu started his faculty career as an Assistant Professor at Villanova University. He was promoted to an Associate Professor with tenure in May 2011.

Dr. Wu applies fundamental principles of fluid dynamics to the bio and bio-inspired applications. His research interests include porous medial flow, fluid dynamic and transport aspects of cardiovascular diseases, cellular mechanisms for mechanotransduction, bone fluid flow, the lift mechanics of skiing, and soft/super lubrication. He has published extensively on these topics. Especially, Dr. Wu’s group is widely recognized for developing a novel experimental and theoretical approach to study the lift generation inside soft porous media. This approach was successfully applied to such diverse problems as the frictionless motion of a red cell in a tightly fitting capillary, the lift forces generated during skiing or snowboarding, the design of a futuristic train track, in addition to classical lubrication theory applications. This research was reported extensively in Science®, Nature®, Scientific American®, PhysicsWeb®, Discover Channel ® and hundreds of public media world widely.

 

主持人：熊春阳  教授

时  间：2012年7月17日（周二）上午9:00

地  点：工学院1号楼212会议室