2019-20 Distinguished Seminar Series

Abstract

I studied engineering in college, because folks told me that engineering was for people who liked math and science and who wanted to do something with these subjects. In my career, I have had the pleasure of tackling big problems as an engineer at two national laboratories and at the White House. In my current job, I lead technical initiatives and oversee core scientific capabilities as the Deputy Director for Science and Technology at the Lawrence Livermore National Laboratory (LLNL). LLNL is a large ($2B budget with about 7000 employees) multi-disciplinary scientific laboratory located in northern California that provides solutions to the nation’s most important national security challenges through innovative science, engineering and technology. Engineering has provided me with a toolset that I continue to hone with each new challenge. 

Bio

Patricia Falcone is the Deputy Director for Science and Technology at the Lawrence Livermore National Laboratory in Livermore, California. She is the principal advocate for the Lab’s science and technology base and oversees the strategic development of the lab’s capabilities. She is responsible for the lab’s collaborative research with academia and the private sector as well as its internal investment portfolio. Falcone joined LLNL in 2015 after six years at the White House Office of Science and Technology Policy where she served as the Senate-confirmed Associate Director for National Security and International Affairs. Earlier, Falcone served in a variety of technical and management positions at the Sandia National Laboratories in Livermore, California, including as a Distinguished Member of the Technical Staff. Falcone received a BSE in aerospace and mechanical sciences from Princeton University and MS and PhD degrees in mechanical engineering from Stanford University.

Abstract

Mollusk shells are an ideal model system for understanding the morpho-elastic basis of morphological evolution of invertebrates' exoskeletons. During the formation of the shell, the mantle tissue secretes proteins and minerals that calcify to form a new incremental layer of the exoskeleton. Most of the existing literature on the morphology of mollusks is descriptive. The mathematical understanding of the underlying coupling between pre-existing shell morphology,

de novo surface deposition and morpho-elastic volume growth is at a nascent stage, primarily limited to reduced geometric representations. Here, we propose a general, three-dimensional computational framework coupling pre-existing morphology, incremental surface growth by accretion, and morpho-elastic volume growth. We exercise this framework by applying it to explain the stepwise morphogenesis of seashells during growth: new material surfaces are laid down by accretive growth on the mantle whose form is determined by its morpho-elastic growth. Calcification of the newest surfaces extends the shell as well as creates a new scaffold that constrains the next growth step. We study the effects of surface and volumetric growth rates and of previously deposited shell geometries on the resulting modes of mantle deformation and therefore of the developing shell's morphology. Connections are made to a range of complex shells ornamentations. This is joint work with Shiva Rudraraju (U Wisconsin), Regis Chirat (U Lyons), Derek Moulton and Alain Goriely (U Oxford).

Bio

Krishna Garikipati obtained his BS degree from the Indian Institute of Technology, Bombay, in 1991, a MS and PhD from Stanford University in 1992 and 1996 respectively. After a few years of post-doctoral work, he joined the faculty at University of Michigan in 2000 where since 2012 he has been a professor in the Departments of Mechanical Engineering and of Mathematics. His research draws on applied mathematics and numerical methods to explain phenomena in biophysics and materials physics. A recent interest is in using data-driven methods to enhance our ability to solve computational physics problems. In 2016, he was appointed the Director of the Michigan Institute for Computational Discovery and Engineering (MICDE), a research institute focused on developing new paradigms of computational science that cut across application areas. He has been awarded the DOE Early Career Award, the Presidential Early Career Award for Scientists and Engineers and a Humboldt Research Fellowship.

Abstract

In moving toward a more sustainable future, we must develop more efficient means to convert and utilize energy. This presentation will highlight the recent work of Dr. Schaefer’s lab on a number of energy systems which are unified through the application of rigorous thermofluid modeling, both on the small scale and at the systems level. An overview will be presented of the lattice Boltzmann method (LBM), including its ability to capture particle interactions without high computational complexity. The mesoscopic particle distribution functions of the LBM allow for simulation of the multiphase, multicomponent thermal flows that are common in a range of energy systems. Improvements to the LBM will also be discussed, along with the challenges in extending the method to capture higher-order behavior. Finally, examples will be presented on how the LBM, along with more conventional CFD and heat transfer approaches, can be useful in designing and implementing advanced energy systems.

Bio

Dr. Laura Schaefer is Chair of the Department of Mechanical Engineering at Rice University as well as a Burton J. and Ann M. McMurtry Chaired Professor. Dr. Schaefer received a BS in Mechanical Engineering (1995) and a BA in English (1995) from Rice University, and her MS (1997) and Ph.D. (2000) degrees in Mechanical Engineering from Georgia Tech. She was a faculty member in Mechanical Engineering at the University of Pittsburgh from 2000-2015 where she was also Deputy Director of the Mascaro Center for Sustainable Innovation and Associate Director of the Center for Energy. Dr. Schaefer’s research has received over $12 million in funding by organizations such as NSF, AFOSR, ASHRAE, PITA and NCIIA. She is a Fellow of the American Society of Mechanical Engineers, the Editor-in-Chief of the Elsevier journal Sustainable Energy Technologies and Assessments, an Associate Editor of the ASME Journal of Heat Transfer and a past Chair of the Advanced Energy Systems Division of ASME.

Abstract

The prospect of developing materials with the energy density of batteries and the power density and cycle life of electrical double-layer capacitors is an exciting direction that has yet to be realized. With these materials, there is the promise of achieving charging in minutes to storage levels comparable to battery electrode materials. One pathway which offers the possibility for achieving this combination of properties is pseudocapacitance.

An underlying assumption with pseudocapacitive materials is that charge-storage kinetics are not characterized by semi-infinite diffusion. Instead, the ion diffusion length l and the diffusion coefficient D are considered to be related by l << (Dt)^1/2, where t is diffusion time. There has been considerable success in creating nanoscale materials which exhibit pseudocapacitive properties. One reason for this is that when the thickness of the material is very small, i.e. less than the characteristic diffusion length, diffusion of redox reactions is governed by thin-layer electrochemistry. Under these conditions, faradaic reactions occur within a finite diffusion space and redox kinetics begin to resemble capacitive processes. We consider such materials to be ‘extrinsic pseudocapacitors’ in that materials which exhibit battery-type behavior as bulk solids, change their electrochemical characteristics and exhibit pseudocapacitive responses when reduced to nanoscale dimensions. This mechanism change has been associated with decreasing ionic and electronic diffusion distances, suppressing phase transitions, and increasing the number of available surface sites for Li⁺.  In this paper, we will review extrinsic pseudocapacitive behavior for several nanoscale materials systems including MoO₂, LiMn₂O₄ and MoS₂ and show how their fast kinetics and pseudocapacitive responses arise from thin layer electrochemistry considerations. Pseudocapacitive materials fill an important gap in the energy storage field, namely having solids that possess the energy density of battery materials with the power density of capacitive materials. It is certain that interest in these materials will continue to expand as their unique combination of properties will meet the needs of several of the expected growth areas for energy storage.

Bio

Bruce Dunn is the Nippon Sheet Glass Professor of Materials Science and Engineering at UCLA. Prior to joining UCLA, he was a staff scientist at the General Electric Research and Development Center. His research interests concern the synthesis of inorganic and organic/inorganic materials and characterization of their electrical, optical, biological and electrochemical properties. A continuing theme in his research is the use of sol-gel methods to synthesize materials with designed microstructures and properties. His recent work on electrochemical energy storage includes three-dimensional batteries and pseudocapacitor materials. Among the honors he has received are a Fulbright research fellowship, the Orton Lectureship from the American Ceramic Society, awards from the Department of Energy and invited professorships in France, Japan and Singapore. He is a Fellow of the Materials Research Society, the American Ceramic Society and a member of the World Academy of Ceramics. In addition to the Board of Reviewing Editors at Science, he is a member of the editorial boards of the Journal of the American Ceramic Society, Advanced Energy Materials, Solid State Ionics and Energy Storage Materials.

Abstract

Ulaanbaatar, the capital of Mongolia, is commonly ranked among the worst cities in the world for outdoor particulate matter air pollution. Air quality conditions are particularly poor during the wintertime because of the extreme climate and high demand for energy to satisfy space heating needs. A major source of pollution is coal combustion in residential heating stoves with these activities centered in the ger districts of the city. The U.S. Millennium Challenge Corporation, through a compact with the Mongolian Government, funded a residential stove replacement program and within a few years more than 100,000 stoves were sold which represents about half of the stoves in the city. This presentation will focus on Ulaanbaatar’s air quality conditions in general and an impact assessment conducted to quantify the benefits of this investment. The assessment instruments included a household survey to determine fuel consumption and stove usage patterns, household stove emissions testing and indoor air quality measurements, and outdoor air quality measurements and modeling. In a separate study the impact assessment findings were placed in a broader context by projecting air pollution health impacts to 2024 for a suite of emission control scenarios. Health impacts were estimated using the latest measures from the Comparative Risk Assessments of the Global Burden of Disease Project. In addition to these two projects, our current work in Mongolia will also be outlined.

Bio

Jay Turner is a Professor of Energy, Environmental and Chemical Engineering, and Vice Dean for Education in the James McKelvey School of Engineering at Washington University in St. Louis. His research primarily focuses on air quality characterization with emphasis on field measurements and data analysis to support a variety of applications in the atmospheric science, regulation and policy, emissions estimation, exposure assessment, and health studies arenas. He is currently PI for a UNICEF-funded project in Mongolia to develop air quality monitoring systems for children’s health and is Co-PI for three NIH-funded projects to: examine relationships between air pollution and neurodegenerative disease; conduct passive and mobile platform measurements to assess the air quality impacts of a neighborhood-scale greening intervention; and to develop and deploy a high time resolution monitor for mobile mapping of VOC compounds. In the last two years, he was also PI for a FHWA/DOT-funded project to quantify the efficacy of an engineered vegetative buffer to attenuate near-road air pollution. Dr. Turner currently serves on the USEPA’s chartered Science Advisory Board (SAB). He is a past president of American Association for Aerosol Research (AAAR) and currently Air Group Coordinator for the Air & Waste management Association (A&WMA).

Abstract

While the characteristic times scales associated with fire propagation/suppression and high-speed reacting flows differ by orders of magnitude, the same fundamental transport and finite-rate chemical kinetic principles can be applied to address challenging issues in both systems. During this presentation, the breadth of fundamental reacting flow investigations supported by the NSF Combustion and Fire Systems Program will be highlighted. More importantly, often overlooked collaborative and cross-cutting funding opportunities available for researchers in engineering will be discussed.

Bio

Harsha Chelliah is the Program Director of the Combustion and Fire Systems at the National Science Foundation since November of 2018. He is also a Professor of Mechanical and Aerospace Engineering at the University of Virginia (UVa). Prior to joining UVa, he received his PhD in Mechanical and Aerospace Engineering from Princeton University in 1988. His research is focused on fundamental interactions between finite-rate kinetics and fluid flow using both experimental and modeling approaches. He was the Director of the Commonwealth Center for Aerospace Propulsion Systems (from 2011-2014) established by the Commonwealth of Virginia and Rolls-Royce. In addition, he also served as Director of the Graduate Studies in Mechanical and Aerospace Engineering (from 2011-2015). He is an active member of the American Institute of Aeronautics and Astronautics (AIAA), the American Society of Mechanical Engineers (ASME), and the Combustion Institute. He is a Fellow of ASME, an Associate Fellow of AIAA and a Visiting Fellow at Peterhouse College, Cambridge University. He currently serves on the editorial board of the Journal on Combustion Theory and Modeling.