Center for Fluid Mechanics
And
The Fluids, Thermal And Chemical Processes Group
Of
The Division of Engineering
Seminar Series
Department of Mechanical Engineering, Polytechnic University, Brooklyn, NY | |
Abstract: Flow in the human body is designed to be laminar and regular. A few exceptions where turbulence plays a role are speech production and pathological flow in the circulatory system. Speech production involves unsteady pulsatile flow and turbulent structures that affect the aeroacoustics. Examples of pathological blood flow in which unsteadiness, separation and turbulence are important include regurgitant heart valves, stenoses or blockages, and branches and bifurcations. Pulsatile unsteady phenomena, coherent vortical structures and transitional flow or turbulence occurring at low Reynolds numbers are common to these biological flows. An overarching motivation for studying hemodynamics and speech production is to facilitate surgical planning, i.e. to enable physicians to assess the outcomes of surgical procedures by using faithful computer simulations. Such simulations are on the horizon with the advent of increasingly more powerful high performance computing and cyberinfrastructure, but they still lack all the appropriate models. This seminar will emphasize our cardiovascular-flow-related research program, where the goal is to investigate the fluid dynamics stimuli of pathological flows on the endothelial cells lining the intima of the arteries. The motivation is to understand the cycle of plaque formation that occurs in the disease atherosclerosis. A multidisciplinary effort with colleagues in Biomedical Engineering enables study of the fluid dynamics in the presence of live cells. Because actual cells are subjected to the flow and then analyzed for biochemical and genetic response, the facility cannot be scaled-up. Thus, techniques such as micro-PIV and MEMS-based wall shear stress sensors are required to characterize the flow. Another important objective is to enable computations with realistic inlet and boundary conditions. Our work on perturbations addresses the sensitivity of pulsatile flow in arteries to changes in inlet conditions such as curvature and velocity profile distortion.
Biographical Sketch: Dr. Michael W. Plesniak is the Eugene Kleiner Professor for Innovation in Mechanical Engineering at Polytechnic University in Brooklyn, NY and an Adjunct Professor of Mechanical Engineering at Purdue University. He recently completed a term as the Director of the Fluid Dynamics & Hydraulics program at the National Science Foundation. Prof. Plesniak earned his Ph.D. degree from Stanford University, and his M.S. and B.S degrees from the Illinois Institute of Technology; all in Mechanical Engineering. Dr. Plesniak was elected a Fellow of ASME in 2006. His current research interests include: bio fluid mechanics, turbulence transport and mixing enhancement, cavitation, three-dimensional boundary layers, gas turbine cooling, environmentally-benign consumer aerosol sprays, and entrainment control. Dr. Plesniak has authored one hundred refereed archival publications and conference papers, over fifty non-refereed publications and presentations, and has presented numerous invited seminars and keynote addresses. He has served as an Associate Editor for the ASME Journal of Fluids Engineering.
Special Scientific Computing Seminar
Abstract: The simplest form of the photonic crystal is a one-dimensional periodic structure, such as a multilayer film (a Bragg mirror). A prominent example of the photonic crystal phenomenon is the naturally occurring gemstone opal. Its play of colors is essentially a photonic crystal phenomenon based on Bragg diffraction of light on the crystal's lattice planes. In this presentation, we propose a new stochastic model for general spatially incoherent sources with applications to photonic crystal spectrometer design. The model naturally incorporates the incoherent property and leads to stochastic Maxwell equations. We propose fast numerical methods based on Wiener Chaos Expansions (WCE), which converts the random equations into system of deterministic equations, so that they can be solved using efficient deterministic methods. Comparing to the Monte Carlo methods for stochastic PDE's, the WCE methods are more efficient and have better error control. In addition, they do not require random number generation. In applications to the photonic crystal, the new method provides up to two orders of magnitude improvement in the speed of computations as compared to the standard methods. This is a joint work with S.N. Chow, Ali Adibi and M. Badiei.
Brown University -
Center for Computational Molecular Biology Seminar Series
Albert Williams Professor of Biomedical Informatics, Molecular Biophysics & Biochemistry, Computer Science Yale University | |
Abstract: My talk will be concerned with topics in proteomics, in particular predicting protein function on a genomic scale. We approach this through the prediction and analysis of biological networks -- both of protein-protein interactions and transcription-factor-target relationships. I will describe how these networks can be determined through integration of many genomic features and how they can be analyzed in terms of various simple topological statistics. I will discuss the accuracy of various reconstructed quantities.
http://bioinfo.mbb.yale.edu
http://topnet.gersteinlab.org
Brown University -
Division of Applied Mathematics,
TRANSATLANTIC SEMINARS
Brown University - Graduate School,
Division of Applied Mathematics,
Dissertation
PDE Seminar
Abstract: I will explain how a system of coupled massive quantum particles can be thought of as a device for elementary quantum computations. The mathematical context is the study of temporal scattering for a system of Schrodinger equations and the resulting entanglement of the states.
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