Title: Modified Equation Analysis for Temporal Oscillation Removal in the Nonlinear Heat Equation
Abstract: We first review the mimetic finite difference (MFD) method for discretizing the governing parabolic equation. This method discretely mimics desired properties of the continuous partial differential equation (PDE). Applications of this equation arise
in heat conduction and in geophysical subsurface flows. We consider the numerically challenging case, where the diffusion coefficients or permeabilities tend towards zero. Results of various averages, including harmonic and arithmetic, as well as newly
developed ones are then compared. Furthermore, in this talk, we will discuss the temporal oscillations formed with nonlinear permeabilities and sharp pressure gradients. These temporal oscillations occur, even though there are no visible oscillations on the
spatial scale. We consider the case where the permeabilities are a low-degree monomial of the pressure. Modified Equation Analysis is used to correct for the oscillations present in the harmonic average case. Lastly, we examine discontinuous and nonlinear
permeabilities, where a newly developed average, which utilizes the shock position removes the temporal oscillations.
Time: 4:30-5:20 p.m.
Location: Hewlett 102
TUESDAY, JANUARY 24, 2017 CME 300: First Year Seminar Series Speaker: Marco Pavone, Assistant Professor of Aeronautics and Astronautics and, by courtesy, of Electrical Engineering
Bio: Dr. Marco Pavone is an Assistant Professor of Aeronautics and Astronautics at Stanford University, where he also holds courtesy appointments in the Department of Electrical Engineering, in the Institute for Computational and Mathematical Engineering, and in the Information Systems Laboratory. He is a Research Affiliate at the NASA Jet Propulsion Laboratory (JPL), California Institute of Technology. Before joining Stanford, he was a Research Technologist within the Robotics Section at JPL. He received a Ph.D. degree in Aeronautics and Astronautics from the Massachusetts Institute of Technology in 2010. Dr. Pavone’s areas of expertise lie in the fields of controls and robotics.
Dr. Pavone is a recipient of an NSF CAREER Award, a NASA Early Career Faculty Award, a Hellman Faculty Scholar Award, and was named NASA NIAC Fellow in 2011. At JPL, Dr. Pavone worked on the end-to-end optimization of the mission architecture for the Mars sample return mission. He has designed control algorithms for formation flying that have been successfully tested on board the International Space Station.
Dr. Pavone is the Director of the Autonomous Systems Laboratory (ASL). The goal of ASL is the development of methodologies for the analysis, design, and control of autonomous systems, with a particular emphasis on large-scale robotic networks and autonomous aerospace vehicles. The lab combines expertise from control theory, robotics, optimization, and operations research to develop the theoretical foundations for networked autonomous systems operating in uncertain, rapidly-changing, and potentially adversarial environments. Theoretical insights are then used to devise practical, computationally-efficient, and provably-correct algorithms for field deployment. Applications include robotic transportation networks, sensor networks, agile control of spacecraft during proximity operations, and mobility platforms for extreme planetary environments. Collaborations with NASA centers are a key component of the research portfolio.
Time: 12:30-1:20 p.m.
Location: Y2E2-105 *note change in room
THURSDAY, JANUARY 26, 2017 CME 510: Linear Algebra and Optimization Seminar Speaker: Alberto Pepe, Authorea
Title: Open Science, Data-Driven Scholarship, and the Future of Academic Publishing
Abstract: Most tools that scientists use for the preparation of scholarly manuscripts, such as Microsoft Word and LaTeX, function offline and don't account for the born-digital nature of research objects. Further, most authoring tools in use today are not designed for collaboration. As scientific collaborations grow in size, research transparency and the attribution of scholarly credit are at stake. I will show how Authorea allows scientists to write rich data-driven manuscripts on the web; articles that natively offer readers a dynamic, interactive experience with an article's full text, images, data, and code, paving the way to increased data sharing, research reproducibility, and Open Science. I will also demonstrate how Authorea differs from Overleaf and ShareLaTeX.
Time: 4:30-5:30 p.m.
Location: Y2E2-101
OTHER ICME RELATED SEMINARS: Applied Math Seminar Wednesday, January 25, 2017 Speaker: Mark Alber, UC Riverside and University of Notre Dame
Title: Combined Multi-scale Computational and Experimental Studies of Bacterial Swarming and Blood Clot Formation
Abstract: Surface motility such as swarming is thought to precede biofilm formation during infection. Population of bacteria P. aeruginosa, major infection in hospitals, will be shown to efficiently propagate as high density waves that move symmetrically as rings within swarms towards the extending tendrils. Multi-scale model simulations suggest a mechanism of wave propagation as well as branched tendril formation at the edge of the population that depend upon competition between the changing viscosity of the bacterial liquid suspension and the liquid film boundary expansion caused by Marangoni forces. This collective mechanism of cell-cell coordination was shown to moderate swarming direction of individual bacteria to avoid antibiotics. In the second half of the talk, a novel three-dimensional multi-scale model will be described for simulating receptor-mediated adhesion of deformable platelets at the site of vascular injury under different shear rates of blood flow. The modeling approach couples submodels at three biological scales crucial for the early clot formation: novel hybrid cell membrane submodel to represent physiological elastic properties of a platelet, stochastic receptor–ligand binding submodel to describe cell adhesion kinetics and lattice Boltzmann submodel for simulating blood flow. Predictive model simulations revealed that platelet deformation, interactions between platelets in the vicinity of the vessel wall as well as the number of functional GPIbα platelet receptors played significant roles in platelet adhesion to the injury site. Lastly, macro- scale model of blood clot deformation and deformation of blood vessel will be described. The model represents clot as a ternary complex fluid made of heterogeneously distributed platelets, fibrin network and plasma phases and takes into account mechanical properties of different phases.
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