Nina C. Shapley
Rm 817 Mudd, Mail Code: 4721
Phone: +1 212-854-1095
Fax: +1 212-854-3054
Email:
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Education:
A.B. Physics, Harvard University, 1993.
Ph.D. Chemical Engineering, Massachusetts Institute of Technology, 2000.
Research interests:
Our research focuses on multiphase fluid mechanics and biomedical applications. Flows of dispersions are encountered frequently in current bioprocessing, medical imaging, and drug delivery applications. A typical dispersion can take the form of an emulsion of liquid droplets or a suspension of cells, solid particles, or bubbles. In many such biological applications, dispersion microstructure and flow properties play critical roles. However, the dispersions often lack optimal physical properties and flow behavior for their intended functions. Understanding of the detailed structure and dynamics of biological flow processes is needed to optimize the dispersion properties and the choice of operating conditions. In addition, the fascinating flow properties of emulsions and suspensions known from prior research can be utilized in novel ways.
It has been observed that particulate suspensions readily redistribute their microstructure in response to variations in shear and normal stresses in a flow. In dispersions where there is a density difference between the particles (or droplets) and surrounding liquid, even small concentration variations can strongly affect the flow patterns. Blood is an example of a concentrated suspension, with typically 45% volume fraction blood cells, where there is also a density difference between the cells and plasma. Previous work has demonstrated that flow-induced, nonuniform blood cell distributions have been observed in the microcirculation. What happens in larger vessels? Also, when we inject particulate contrast agents such as fluorocarbon droplets for MRI, microbubbles for ultrasound, or drug delivery microspheres in the circulation, we need to know how these “other” particles are distributed. We are interested in these questions and also in potentially developing dispersions for detection of atherosclerosis risk and preventive measures. Many prior studies have correlated enhanced risk of developing atherosclerosis (vascular wall thickening) in certain regions of the arterial wall with fluid mechanical factors. We aim to understand the role of the particulate nature of blood in this process, and in the possible engineering of particulates detectable by MRI that would identify atherosclerosis–prone regions by accumulation. Another related area of interest is monitoring mixing and stress during tissue growth in rotating-wall vessel bioreactors.
Noninvasive measurement techniques we use to follow flowing particulates include nuclear magnetic resonance imaging (NMRI) and optical methods such as video imaging and laser Doppler velocimetry. These techniques are complementary in that NMR imaging is a technique well-suited to measuring concentration and velocity profiles in opaque systems and in vivo, while optical methods provide high-resolution measurements in model systems. From the combination of these techniques, we can “see” into biological flows in new ways.
Selected Publications:2008 C. Xi and N.C. Shapley, “Comparison of flows of concentrated suspensions through bifurcations with equal and unequal branches,” submitted, Physics of Fluids.
2008 C. Xi and N.C. Shapley, “Flows of concentrated suspensions through an asymmetric bifurcation,” Journal of Rheology 52: 625-647.
2007 T. Moraczewski and N.C. Shapley, “Pressure drop enhancement in a concentrated suspension flowing through an abrupt axisymmetric contraction-expansion,” Physics of Fluids 19: 103304.
2007 H.J. Hester-Reilly and N.C. Shapley, “Imaging contrast effects in alginate microbeads containing trapped emulsion droplets,” Journal of Magnetic Resonance 188: 168–175.
2007 M.U. Larsen and N. C. Shapley, “Stream spreading in multilayer microfluidic flows of suspensions,” Analytical Chemistry 79: 1947-1953.
2006 T. Moraczewski and N.C. Shapley, “The effect of inlet conditions on concentrated suspension flows in abrupt expansions,” Physics of Fluids 18: 123303.
2006 M.A. d'Avila, N.C. Shapley, J.H. Walton, R.J. Phillips, R.L. Powell and S.R. Dungan, “A novel gravity-induced flow transition in two-phase fluids,” Physics of Fluids 18: 103305.
2005 T. Moraczewski, H. Tang, and N.C. Shapley, “Flow of a concentrated suspension through an abrupt axisymmetric expansion measured by nuclear magnetic resonance imaging,” Journal of Rheology 49: 1409-1428.
2004 Leonard, E.F., West, A.C., Shapley, N.C. and Larsen, M.U. "Dialysis without membranes: How and why?" Blood Purification 22: 92-100