Abstract: Being comprised entirely of charged species, ionic liquids (IL) and molten salts (MS) have dramatically different properties compared to conventional molecular liquids and they provide new and unusual environments to test our understanding  of physical chemistry phenomena. We are interested in how IL and MS properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of reactions and product distributions, for example in the areas of primary and applied radiation chemistry, radical chemistry and charge transfer reactions. A key issue in IL radiolysis is the competition between the solvation of the  initially-formed excess electrons and the scavenging of electrons in different states of solvation. Pre-solvated electron scavenging is especially significant in ILs because their relatively high viscosities make their solvation dynamics 100-1000x slower than in conventional solvents. The slower relaxation dynamics of ILs make them excellent media for the general study of fundamental radiolysis processes, in combination with BNL’s Laser-Electron Accelerator Facility (LEAF) for picosecond pulse radiolysis studies. With LEAF we can observe the solvation processes of radiolytically- generated excess electrons and compare and contrast them with the mechanisms of pre-solvated electron scavenging. In molten salts, identifying the primary radiolysis products and characterizing their reactivities is important to understand the chemical evolution of the molten salt fuel over the duration of its lifetime in the reactor. Examples will be given of how the composition of the salt determines the identities and reactivities of the primary radiolysis products. The work on molten salts was supported as part of the Molten Salts in Extreme Environments Energy Frontier Research Center, funded by the U.S. Department of Energy Office of Science. The work on ionic liquids was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, under contract DE-SC0012704.

Biographical Sketch: James Wishart earned his Bachelors degree in Chemistry from the Massachusetts Institute of Technology (1979), and his Ph.D. in Inorganic Chemistry from Stanford University (1985) (Advisor: Henry Taube, Nobel Prize in Chemistry, 1983). Dr. Wishart is currently a Senior Chemist in the Chemistry Division of Brookhaven National Laboratory, where he has worked for 32 years. He has been studying the physical chemistry and radiation chemistry of ionic liquids, and recently molten salts, for 18 years. Dr. Wishart is currently the Director of the Molten Salts in Extreme Environments Energy Frontier Research Center. He is the leader of the BNL Accelerator Center for Energy Research (ACER), including the Laser-Electron  Accelerator Facility (LEAF) for picosecond pulse radiolysis, which he also built in the 1990s. In September 2019, he received the Maria Skłodowska-Curie Medal from the Polish Radiation Research Society, for his distinguished achievements in the field of radiation chemistry and long-lasting and productive cooperation with Polish scientists.

 

Abstract: Electronic and biological systems represent two limiting thermodynamic models in terms of functioning and information processing. By converging the dynamic and self-adaptable features of bio-machinery and the rationally defined/programmed functionalities of electronic components, there is potential to evolve new capabilities to effectively interrogate and direct biologically significant processes, as well as novel bio-inspired systems/device concepts for a range of engineering applications. The intrinsic mismatches in physiochemical properties and signaling modality at biotic/abiotic interfaces, however, have made the seamless integration challenging. In this talk, I will present our recent effort in forging their structural and functional synergy through the design and development of: (1) bio-hybrid electronics, where living transducers, such as functional biomolecules, organelles, or cells, are integrated with electronic transducers using spatially-defined, biocompatible hydrogel as the interfacing material; and (2) biosynthetic electronics, where biogenic electron pathways are utilized to naturally bridge the gap between internal biological and external electrical circuits. Blurring the distinction between livings and non-livings, these efforts have the potential to facilitate the cross-system communication and broadly impact how complex structures/functions may be designed/engineered.

Biographical Sketch: Xiaocheng Jiang is an Assistant Professor in the Department of Biomedical Engineering at Tufts University. He received his Ph.D. in physical chemistry from Harvard University with Professor Charles Lieber, with a focus on the design and application of nanoscale materials and nanoelectronic devices. Prior to joining Tufts, he was an American Cancer Society postdoctoral fellow at Massachusetts General Hospital, where he worked with Prof. Mehmet Toner on functional microfluidics for early cancer diagnostics. His current research concentrates broadly at the interface of materials and biomedical science, with specific interests in bio-inspired/bio-integrable electronics. He is a recipient of NSF CAREER award (2017) and AFOSR young investigator award (2018).

 

Abstract: The water flow through tidal estuaries create a large source of renewable energy that is highly predictable and close to urban centers, yet mostly untapped in the United States.  This presentation gives an overview of recent efforts to develop a hydrokinetic energy harvesting device well-suited for tidal flows, that is based on the oscillating motion of hydrofoils. Inspired from the flapping flight of birds and bats, an oscillating hydrofoil generates energy through lift generation, which is augmented by a large unsteady leading-edge vortex. This talk will highlight the computational efforts that drove prototype development and will examine the flow physics important for energy capture. It will also discuss the formation and downstream trajectory of the leading-edge vortex, which is important for informing the configuration of oscillating foil arrays. Knowing the path and topology of shed vortices can enable downstream foils to be placed strategically and recapture the kinetic energy of vortices, thus boosting the system efficiency of an oscillating foil array.

Biographical Sketch: Dr. Jennifer Franck is an expert in computational fluid dynamics (CFD) and is interested in unsteady flow phenomena and flow control of turbulent flows.  She is currently an Assistant Professor in Engineering Physics at University of Wisconsin-Madison. Prior to moving to Madison, she was on the faculty at Brown University’s School of Engineering for seven years where she won numerous teaching and advising awards.  She received her undergraduate degree in Aerospace Engineering from University of Virginia, followed by a M.S. and Ph.D. from California Institute of Technology. She was awarded an NSF Postdoctoral Fellowship to computationally explore flapping flight mechanisms at Brown University from 2009-2011. Dr. Franck is currently interested in problems related to renewable energy, including wind and tidal energy applications.

Abstract: The mission  of AFRL’s Multidisciplinary Science and Technology Center (MSTC) is to discover, assess, and exploit coupled system behavior for optimization of revolutionary aerospace vehicles through the application of multidisciplinary design, analysis, and optimization (MDAO). To this end, MSTC performs  in-house research and sponsors efforts ranging from basic developments in FEA, CFD, design space exploration, physics-based design, and experimental testing through technology demonstration vehicles including the X-56 and XQ-58A. An area of ongoing interest in MSTC is the development of topology optimization (TO) methodologies for the design of efficient aircraft structure. Commercially available tools for TO have successfully been employed for aircraft components such as lightweight brackets and other localized components. However, it remains a challenge to utilize these density-based methods to design aircraft primary structure that is subject to diverse design constraints including aeroelastic deformations, flutter, panel buckling, stress requirements, and control effectiveness criteria. To address this challenge, a biologically-inspired technique based on the production rules governing cellular division of living organisms has been developed and applied to identify optimal topological layouts of air vehicle structure. Preliminary results demonstrate over 10% reductions in structural weight is from TO compared to optimally-sized structure with conventional structural topology. In addition, the performance  of resulting designs has been validated using 3D printing and static/modal testing of subscale models. This talk will provide an overview of ongoing efforts in AFRL’s MSTC and will introduce the bio-inspired method for the topology optimization of aircraft structures.

Biographical Sketch: Joshua Deaton is a Research Aerospace Engineer in AFRL’s Aerospace Systems Directorate’s Multidisciplinary Science and Technology Center (MSTC). In this role Dr. Deaton develops and applies multidisciplinary computational design technologies and leads collaborative efforts with industry, academia, and other government partners to transition multidisciplinary design technology to support the design of next-generation Air Force platforms. His primary research areas include coupled sensitivity analysis, structural and topology optimization, and nonlinear thermoelasticity. Dr. Deaton received his Ph.D. in Engineering with a focus on Computational Design and Optimization as well as his B.Sc. in Mechanical Eng. from Wright State University. He serves on the AIAA Multidisciplinary Design Optimization (MDO) Technical Committee and recently received the Outstanding Technical Contribution – Science Award from the AIAA Dayton-Cincinnati Section for his contributions in multidisciplinary sensitivity analysis for geometrically nonlinear aerospace structures.

 

Abstract: During development, instabilities develop in the brain, giving it its characteristic wrinkled shape. Other soft tissues, including skin, the bladder, and the airway mucosa, also exhibit instabilities and the resulting folds, wrinkles, and creases. Instabilities in these soft tissues, which often contain multiple layers with distinct properties, are very complex and still not well understood. The focus of this talk will be on the unique features of instabilities in soft layered materials, including their sensitivity to different sources of compression, the interactions of adjacent layers and interfaces, the influence of boundary conditions, and the emergence of heterogeneous layer thickness as a result of wrinkling. I will share results from theoretical, computational, physical, and imaging approaches, and discuss their implications for the study of the developing brain.

Biographical Sketch: Maria Holland is the Clare Boothe Luce Assistant Professor of Aerospace and Mechanical Engineering at the University of Notre Dame in Notre Dame, IN. She earned her M.S. and Ph.D. from Stanford University in the Department of Mechanical Engineering with Prof. Ellen Kuhl, and her bachelor’s degree in mechanical engineering from the University of Tulsa, graduating Phi Beta Kappa. Her research is in computational biomechanics, using solid mechanics and computational tools to address important questions about complex soft materials, including the brain. Through collaborations with clinicians and experimentalists, she aims to understand the development of the human brain and how it relates to the brain’s form and function. Additionally, she works to extend the functionality of traditional engineering methods to encompass soft, growing materials.

Abstract: The rapidly expanding interest in molten salt reactors (MSRs), particularly as small modular reactors, is resulting in the generation of multiple design concepts with efforts at a variety of early developmental stages. Various companies and organizations in a number of countries are looking at such systems to be safe, economical, and rapidly deployable power systems. For efficient design, operation, and regulation of MSRs it will be necessary to have the ability to simulate reactor behavior across the spectrum from neutronics and fluid dynamics to corrosion and salt phase behavior. MSRs have not been considered since the original prototype, the Molten Salt Reactor Experiment, that ran successfully from 1965-1969 at Oak Ridge National Laboratory, and thus there is little legacy of useful information. Aspects of potential modeling and simulation of future molten salt reactors will be discussed with respect to the unique challenges they present. Among the current needs are extensive thermophysical and thermochemical properties describing salts and other reactor materials. In particular, the ability to compute chemical and phase equilibria (e.g., potential solid phase precipitation) throughout the molten salt loop(s). Activities and opportunities in these areas will be discussed as contributing to development of a knowledge base for molten salt reactor technology.

Biographical Sketch: Ted Besmann is Professor and SmartState Chair for Transformational Nuclear Technologies, directing the General Atomics Center at the University of South Carolina. Dr. Besmann received his B.E. in chemical engineering from New York University, M.S. in nuclear engineering from Iowa State University, and Ph.D. in nuclear engineering from the Pennsylvania State University. In 1975 he joined ORNL and subsequently became a Group Leader and Distinguished Member of the Research Staff. Besmann’s nearly 40 years at Oak Ridge National Laboratory included a joint appointment in the Nuclear Engineering Department at the University of Tennessee. Besmann has over 160 refereed publications, and is a Fellow of both the American Ceramic Society and the American Nuclear Society. He is chair of the Organization for Economic Cooperation and Development-Nuclear Energy Agency (OECD-NEA) Working Party on Multi-Scale Modeling of Nuclear Fuels and Structural Materials and is vice-chair of their Thermodynamics of Advanced Fuels-International Database program. Dr. Besmann is also Co-Director of the DOE Energy Frontier Research Center led by USC, the Center for Hierarchical Waste Form Materials.

Abstract: In this talk, I will discuss work related to mechanically “programming” soft sensors to respond to a particular mechanical deformation. Advances in 3D-printing, soft polymer fabrication, and other rapid fabrication processes have made the vision of conformal and stretchable mechanical sensors for wearable devices and soft robotics possible. One limitation of these sensors is their low selectivity between different modes of mechanical deformation, such as strain, torsion, and bending.

I will present recent work in enhancing the selectivity of stretchable sensors by using non-planar sensor morphology to bias the sensor towards a particular deformation mode. I will discuss projects including designing a sensor with electrically-tunable sensitivity and the fabrication origami-patterned, deformation-selective flexible sensors.

Biographical Sketch: Kris Dorsey is an assistant professor of engineering in the Picker Engineering Program at Smith College. She was a President’s Postdoctoral Fellow at the University of California, Berkeley and University of California, San Diego. Dr. Dorsey graduated from Carnegie Mellon University with a Ph.D. in Electrical and Computer Engineering and earned her Bachelors of Science in Electrical and Computer Engineering from Olin College.

She founded The MicroSMITHie Lab at Smith College to investigate micro- and miniature-scale sensor design and to prepare undergraduates for graduate study in engineering. Her current research interests include strain-stable, hyperelastic components, novel morphology soft sensors, and sensors for soft robots and wearable devices.

Dr. Dorsey has co-authored several publications on hyperelastic strain sensors, novel soft lithography processes, and the stability of gas chemical sensors. In 2019, she received the NSF CAREER award.

Abstract: Biofilms are surface-attached communities of bacteria that can cause problems including medical infections, fouling, and clogging in industrial applications. By contrast, beneficial biofilms are crucial in applications including waste-water treatment and microbial fuel cells. In this talk, I will discuss about our recent progress in using Vibrio cholerae as a model biofilm former to reveal the mechanical principles underlying biofilm formation, both at the single cell level and at the continuum level. I will first present a new methodology to image living, growing bacterial biofilms at single-cell resolution, and demonstrate how cell-cell adhesion and cell-surface adhesion balance each other to cause V. cholerae to form an ordered, three-dimensional cluster. Next, I will show how extracellular polysaccharides, proteins, and cells function together to define biofilm mechanical and interfacial properties. Finally, I will present various mechanical instabilities that take place when biofilms grow on soft substrates, and how such instabilities, together with interfacial properties, define the morphogenesis process of bacterial biofilms.

Biographical Sketch: Dr. Yan obtained his bachelor’s degree from the College of Chemistry and Molecular Engineering at Peking University in China. As a graduate student, he studied soft matter physics in the Department of Materials Science and Engineering at the University of Illinois, Urbana-Champaign. During his Ph.D., he developed a series of non-equilibrium colloidal materials with dynamic structures controlled by electromagnetic fields. He transitioned to biology for his postdoctoral training, working at Princeton University jointly in the Department of Molecular Biology and the Department of Mechanical and Aerospace Engineering. His current research focus is on bacterial biofilm formation. Dr. Yan received the Career Award at the Scientific Interface from Burroughs Welcome Fund in 2016. He moved to Yale as an Assistant Professor in the Department of Molecular, Cellular and Developmental Biology and Quantitative Biology Institute at Yale University in 2019.