MEAM Seminar Series Spring 2018

For Fall 2017 Seminars, click here.

Seminars are held on Tuesday mornings beginning at 10:45 am in Wu and Chen Auditorium, in Levine Hall (unless otherwise noted).

To be added to the MEAM Events mailing list (which sends notifications regarding all departmental seminars and events) please email us at meam-events@lists.seas.upenn.edu.

January 16

Joel D. Boerckel, Assistant Professor of Orthopaedic Surgery and Bioengineering, University of Pennsylvania

“Reverse-Engineering Skeletal Development”

Abstract:

Reverse engineering is the practice of disassembling a product to understand how it was made and how it works, to enable replication and manufacture of a similar object. My laboratory is interested in understanding the molecular mechanisms by which mechanical stimuli influence morphogenesis and growth in development; and, using this knowledge, we are developing tissue engineering strategies that reproduce developmental programs for postnatal tissue regeneration. In this talk, I will share two data stories that exemplify this crosstalk in bone development and regeneration. In the first, we solved a long-standing controversy in bone regarding the combinatorial roles of the mechanosensitive transcriptional co-activators, YAP and TAZ. In the second, we demonstrated that mechanical stimuli are essential to mimic the process of endochondral bone development for regeneration of large bone defects.

Bio:

Joel Boerckel received his Ph.D. in mechanical engineering from the Georgia Institute of Technology and postdoctoral training in cellular and molecular medicine as an NIH Ruth L Kirschstein postdoctoral fellow at the Cleveland Clinic. He recently moved his laboratory to the University of Pennsylvania from the University of Notre Dame, and is currently an Assistant Professor of Orthopedic Surgery and Bioengineering.

January 18 (Thursday): SPECIAL PHD SEMINAR

Boyang Qin, Ph.D. Candidate, University of Pennsylvania
Advisor: Paulo Arratia

“Elastic Turbulence & Ciliary Kinematics in Viscoelastic Fluids: Nonlinearity at Low Reynolds Number”

1:00 p.m., Raisler Lounge (Room 225), Towne Building

Abstract:

Fluids with microstructures often display complex and nonlinear physical behaviors that cannot be found in simple fluids like water. One example that is ubiquitous in nature and industry is viscoelastic fluid which contain macromolecules or polymers dissolved in an otherwise Newtonian fluid. In this talk, I report experimental results of two such nonlinear phenomena associated with fluid viscoelasticity that are relevant to industrial polymer processing and human health. First, by conducting high-speed velocimetry on the flow of polymeric fluid in a micro-channel, we report evidence of elastic turbulence in a parallel shear flow where the streamline is without curvature. We found “turbulent” pipe drag increase and enhanced mixing associated with the polymeric flow. Moreover, the spectral characteristics and spatial structure of the velocity fluctuation are different from that in a curved geometry. Second, by analyzing the ciliary swimming of the green algae Chlamydomonas reinhardtii in viscoelastic fluid, we show that fluid elasticity alters the beating pattern of the cilia and adversely hinders the swimmer motility. This result suggests the complex coupling between fluid rheology and ciliary beating in biological processes such as muco-clearance in mammalian airways.


January 23

Aaswath Raman, Assistant Professor of Electrical and Systems Engineering, University of Pennsylvania

"Thermal Nanophotonics: Controlling the heat and light that surrounds us"

Abstract:

Nanoscale photonic structures, by their small length scales, can manipulate light and heat in unprecedented ways, thereby enabling new possibilities for energy efficiency and generation. In this talk, I will show how controlling the electromagnetic fields associated with thermal radiation using nanophotonic structures can enable fundamentally new technological capabilities by allowing us to harness an unexploited, renewable thermodynamic resource: the cold of space.

I will present our body of work on radiative sky cooling, whereby sky-facing, thermal photonic structures can passively cool themselves below their surroundings by emitting their heat as thermal radiation at wavelengths where Earth's atmosphere is most transparent. I will show how this cooling effect can persist during the day and, remarkably, with selective thermal emitters passively reach as much as 45°C below ambient. I will discuss related work on using such thermal photonic approaches to passively maintain solar cells at lower temperatures, while maintaining their solar absorption, to improve their operating efficiency. I will also highlight recent work on using this approach to cool fluids passively and integrate such a system with conventional air conditioning and refrigeration systems to improve their operating efficiency. Exciting new prospects for harnessing this effect for other energy and water-conservation applications will also be introduced.

Finally, I will highlight new fundamental and applied research directions for controlling light, and thermal radiation in particular, at mid-infrared wavelengths. Given decades of progress in nanoscale photonics, we now have the opportunity to tackle important energy and environmental challenges by better controlling the radiative heat transfer happening around us everyday.

Bio:

Aaswath Raman is Assistant Professor of Electrical and Systems Engineering at the University of Pennsylvania. His research interests include nanophotonics, metamaterials, thermal sciences, computational methods and energy systems. He is also Co-Founder of SkyCool Systems, a startup commercializing technology related to radiative sky cooling that he originally developed as a Research Associate at Stanford University beginning in 2013.

Aaswath received his Ph.D. in Applied Physics from Stanford University in 2013, and his A.B. in Physics and Astronomy, and M.S. in Computer Science from Harvard University in 2006. Prior to obtaining his Ph.D. he was a Program Manager at Microsoft. He is the recipient of the Sir James Lougheed Award of Distinction from the Government of Alberta, Canada, the SPIE Green Photonics Award for his work on solar cell research and the Stanford Postdoctoral Research Award. In recognition of his work on radiative sky cooling, in 2015 Aaswath was named one of MIT Technology Review’s Innovators Under 35 (TR35).


January 30

Gretar Tryggvason, Charles A. Miller, Jr. Distinguished Professor and Department Head, Department of Mechanical Engineering, Johns Hopkins University

"Direct Numerical Simulations of Complex Multiphase Flows”

Abstract:

Direct numerical simulations (DNS), where every continuum length and time scale are fully resolved, allow us to follow the evolution of complex flows for sufficiently long time so that meaningful statistical quantities can be gathered. Results for relatively simple multifluid and multiphase systems with bubbles and drops in turbulent flows are now available, but new challenges are emerging. First of all, DNS of very large systems are yielding enormous amount of data that, in addition to providing physical insights, opens up new opportunities for the development of lower order models that describe the average or large-scale behavior. Recent results for bubbly flows and the application of machine learning tools to extract closure models from the data suggest one possible strategy. Secondly, success with relatively simple systems calls for simulations of more complex problems. Multiphase flows often produce features such as thin films, filaments, and drops that are much smaller than the dominant flow scales and are well-described by analytical or semi-analytical models. Recent efforts to combine semi-analytical models for thin films using classical thin film theory, and to compute mass transfer in high Schmidt number bubbly flows using boundary layer approximations, in combination with fully resolved numerical simulations of the rest of the flow, are described.

Bio:

Gretar Tryggvason is the Charles A. Miller, Jr. Distinguished Professor at the Johns Hopkins University and the head of the Department of Mechanical Engineering. He received his PhD from Brown University in 1985 and was on the faculty of the University of Michigan in Ann Arbor until 2000, when he moved to Worcester Polytechnic Institute as the head of the Department of Mechanical Engineering. Between 2010 and 2017 he was the Viola D. Hank professor at the University of Notre Dame and the chair of the Department of Aerospace and Mechanical Engineering. Professor Tryggvason is well known for his contributions to computational fluid dynamics; particularly the development of methods for computations of multiphase flows and for pioneering direct numerical simulations of such flows. He served as the editor-in-chief of the Journal of Computational Physics 2002-2015, is a fellow of APS, ASME and AAAS, and the recipient of several awards, including the 2012 ASME Fluids Engineering Award.

February 1 (Thursday): MEAM SPECIAL SEMINAR

Justin W. Wilkerson, Donald D. Harrington Faculty Fellow, Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, and
Assistant Professor & James J. Cain Fellow, Department of Mechanical Engineering, Texas A&M University

“The Role of Crystallographic Defects in Impact Failure”

10:30 a.m., Room 307, Levine Hall

Abstract:

Over the past five decades there has been an intense effort to understand and control the thermomechanical response of materials in extreme environments. A number of technologies critical to our safety and well-being stand to benefit from such understanding including armor and defense systems, next-generation fission and fusion reactors, spacecraft shielding, vehicular crashworthiness, and advanced manufacturing. Materials in such extreme environments often exhibit complex, somewhat non-intuitive mechanical behavior that is difficult to predict with empirical or phenomenological models. Here we discuss our development of a number of multiscale, mechanism-based models that help unravel this inherent complexity. This seminar will focus primarily on the development of an atomistically-informed crystal plasticity framework for deformation and failure of shock compressed single crystals and polycrystals. We further utilize this multiscale modeling framework to provide key insights into the development of reduced-order models, which are helpful in guiding the microstructural design of advanced light-weight armor and shielding materials.

Bio:

Professor Wilkerson’s research and teaching interests lie at the interface of solid mechanics, material science, and physics. His research is focused on multiscale modeling and fundamental experiments that shed light on the nature of the mechanical behavior of materials subject to the kinds of extreme conditions generated in armor and defense applications, nuclear reactors, hypersonic aircraft, rocket motors, as well as the cores and surfaces of planets and asteroids. Presently, Wilkerson is a Donald D. Harrington Faculty Fellow with the Department of Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin. In 2017, Wilkerson joined the Department of Mechanical Engineering at Texas A&M University as an assistant professor and the James J. Cain Faculty Fellow II. From 2015 to 2017, Wilkerson was an assistant professor in the Department of Mechanical Engineering at the University of Texas at San Antonio. Wilkerson obtained his B.S. with highest honors from Texas A&M, followed by an M.S.E and Ph.D. from Johns Hopkins University. While at Hopkins he worked with Dr. KT Ramesh in the Hopkins Extreme Materials Institute (HEMI). Wilkerson’s academic achievements have been recognized and supported by a number of honors and awards, including the AFOSR Young Investigator (YIP) Award, the Ralph E. Powe Junior Faculty Award, the National Science Foundation (NSF) Graduate Research Fellowship, the National Defense Science and Engineering Graduate (NDSEG) Fellowship, and the Ammon S. Andes Award presented annually to recognize the nation’s top aerospace engineering graduate.


February 6

NO SEMINAR

February 13

NO SEMINAR

February 20

Hadi T. Nia, Postdoctoral Fellow, Massachusetts General Hospital and Harvard Medical School

"Solid Stress and Elastic Energy as New Measures of Tumor Mechanopathology”

Abstract:

Solid stress and tissue stiffness affect tumor progression, metastasis and treatment. Unlike stiffness, which can be precisely mapped in tumors, the measurement of solid stresses is challenging. In this seminar, I will present three distinct and quantitative techniques to obtain two-dimensional spatial mappings of solid stress and the resulting elastic energy in excised or in situ tumors with arbitrary shapes and wide size ranges. I will present major findings from the application of these methods in mouse models of primary tumors and metastasis including: (i) solid stress generation depends on both cancer cells and their microenvironment; (ii) solid stress increases with tumor size; and (iii) mechanical confinement by the surrounding tissue significantly contributes to intratumoral solid stress. Finally, I will discuss my more recent work on neurological and vascular impairments induced by solid stress from primary and metastatic brain tumors, and potential pharmacological remedies to counter these effects.

Bio:

Hadi T. Nia is an NIH postdoctoral fellow at Massachusetts General Hospital and Harvard Medical School, supervised by Dr. Rakesh Jain. His research interests include multiscale cancer mechanobiology, and the development of innovative tools and model systems to investigate the physical microenvironment of tumors. He received his Ph.D. under Profs. Alan Grodzinsky and Christine Ortiz at MIT, investigating the molecular origin of solid-fluid interactions in cartilage and its association with osteoarthritis. Hadi has been awarded fellowships from the National Cancer Institute (F32), Fund for Medical Discovery, and Whitaker Health Sciences Fund.

February 21 (Wednesday): MEAM SPECIAL SEMINAR IN FLUIDS

Ismail Hameduddin, Ph.D. Candidate, Department of Mechanical Engineering, Johns Hopkins University

“The Theoretical Approach in Viscoelastic Turbulence”

10:30 a.m., Room 337, Towne Building

Abstract:

Turbulence in viscoelastic flows is a fascinating phenomenon with important technological implications, e.g. drag reduction at high Reynolds numbers and increased mixing efficiencies at low Reynolds numbers. The dynamics of these flows have been extensively studied experimentally over the last seventy years and more recently, in direct numerical simulations (DNS). However, theoretical progress in viscoelastic turbulence has been hindered by the fundamental challenges posed by the need to account for both the velocity as well as the elastic deformation history, encapsulated in the positive--definite conformation tensor. Due to the positivity constraint, the latter tensor is not a vector space quantity and thus classical approaches used to quantitatively analyze turbulence in Newtonian flows cannot be directly extended to viscoelastic flows. For example, classical weakly nonlinear expansions and also the Reynolds decomposition are both problematic. In this talk, I will present an approach we have developed to address this problem. Our approach is based on two principles: one must (a) decompose the elastic deformation rather than the conformation tensor itself, and (b) use the non-Euclidean Riemannian geometry of the set of positive-definite tensors whenever a notion of distance or shortest path is needed. I will illustrate the theory using direct numerical simulations of viscoelastic (FENE-P) channel flow. Several important insights are gleaned from these simulations, demonstrating the efficacy of the proposed approach. The fundamental contributions I present will pave the road for theoretical modelling and analysis of viscoelastic turbulence.

February 27

Michael Ortiz, Frank and Ora-Lee Marble Professor of Aeronautics and Mechanical Engineering, California Institute of Technology

"The Anomalous Yield Behavior of Fused Silica Glass"

Abstract:

We develop a critical-state model of fused silica plasticity on the basis of data mined from molecular dynamics (MD) calculations. The MD data is suggestive of an irreversible densification transition in volumetric compression resulting in permanent, or plastic, densification upon unloading. The MD data also reveals an evolution towards a critical state of constant volume under pressure-shear deformation. The trend towards constant volume is from above, when the glass is overconsolidated, or from below, when it is underconsolidated. We show that these characteristic behaviors are well-captured by a critical state model of plasticity, where the densification law for glass takes the place of the classical consolidation law of granular media and the locus of constant-volume states defines the critical-state line. A salient feature of the critical-state line of fused silica, as identified from the MD data, that renders its yield behavior anomalous is that it is strongly non-convex, owing to the existence of two well-differentiated phases at low and high pressures. We argue that this strong non-convexity of yield explains the patterning that is observed in molecular dynamics calculations of amorphous solids deforming in shear. We employ an explicit and exact rank-$2$ envelope construction to upscale the microscopic critical-state model to the macroscale. Remarkably, owing to the equilibrium constraint the resulting effective macroscopic behavior is still characterized by a non-convex critical-state line. Despite this lack of convexity, the effective macroscopic model is stable against microstructure formation and defines well-posed boundary-value problems.

Bio:

Professor Ortiz received a BS degree in Civil Engineering from the Polytechnic University of Madrid, Spain, and MS and Ph.D. degrees in Civil Engineering from the University of California at Berkeley. From 1984-1995 he held a faculty position in the Division of Engineering of Brown University, where he carried out research activities in the fields of mechanics of materials and computational solid mechanics. He is currently the Frank and Ora Lee Marble Professor of Aeronautics and Mechanical Engineering at the California Institute of Technology, where he has been in the faculty since 1995 and where he has served as the director of Caltech’s DoE/PSAAP Center on High-Energy Density Dynamics of Materials from 2008-2013. Professor Ortiz has been a Fulbright Scholar, a Sherman Fairchild Distinguished Scholar at Caltech, Midwest and Southwest Mechanics Seminar Series Distinguished Speaker, an elected member-at-large of the US Association for Computational Mechanics and a Hans Fischer Senior Fellow of the Institute of Advanced Studies of the Technical University of Munich. He is a Fellow of the US Association for Computational Mechanics, elected Fellow of the American Academy of Arts & Sciences and an elected Member of the US National Academy of Engineering. Professor Ortiz is the recipient of the Alexander von Humboldt Research Award for Senior US Scientists, the IACM International Computational Mechanics Awards for Research, the USACM Computational Structural Mechanics Award, the ISI Highly Cited Researcher Award, the inaugural 2008 Rodney Hill Prize conferred every four years by the IUTAM and 2015 Timoshenko Medal of the ASME. Professor Ortiz has served in the University of California Office of the President Science and Technology Panel, the Los Alamos National Laboratory T-Division Review Committee, the Lawrence Livermore National Laboratory Predictive Science Panel, the Sandia National Laboratories Engineering Sciences External Review Panel, the Lawrence Livermore National Laboratory Chemistry, Materials, Earth and Life Sciences Directorate Review Committee, in the Lawrence Livermore National Laboratory Engineering Directorate Review Committee and in the National Research Council Panel for the Evaluation of QMU. He has been editor of the Journal of Engineering Mechanics of ASCE and of the Journal of Applied Mechanics of the ASME and is presently associate editor of the Journal of the Mechanics and Physics of Solids, the Archive for Rational Mechanics and Analysis, the International Journal for Numerical Methods in Engineering and of Computer Methods in Applied Mechanics and Engineering Journal.

March 6

SPRING BREAK - NO SEMINAR

March 13

SEMINAR POSTPONED TO APRIL 12

March 20

Mahesh M. Bandi, Assistant Professor, Collective Interactions Unit, Okinawa Institute of Science and Technology Graduate University

“Applying Higher-order Turbulence Spectra from Energy to UAV”

Abstract:

Kolmogorov’s 1941 theory elucidating the spectrum of turbulent velocity fluctuations forms the cornerstone of contemporary turbulence research. This result requires one to measure the velocity everywhere within the turbulent flow at the same time instant. However, many situations exist where measurements are needed over time at one or few fixed spatial (Eulerian) locations, often involving higher powers of velocity. The physical interpretation of such measurements strongly diverges from the Kolmogorov framework. In this talk, I will review the revised theoretical framework and support it with evidence from our experiments in two and three dimensional flows. I will then explain how this revised framework provides a toolkit to address a diverse range of questions in Energy, UAV mechanics, Environmental Sciences, and even Life Sciences.

Bio:

Mahesh Bandi received his Bachelors’ in Computer Engineering from the University of Madras, India in 1998. After a 2 year stint in the Indian software industry, he returned to academia to pursue further studies. He earned his MS Electrical Engineering in 2002, MS Physics in 2004, and PhD Physics in 2006, all from the University of Pittsburgh. Following postdoctoral stints at Los Alamos National Laboratory (2006 - 2009) and Harvard University (2009 - 2011), Mahesh was appointed to the founding faculty of OIST Graduate University in 2011, where he is currently an Assistant Professor heading the Collective Interactions Unit. He was a visiting faculty with the Brown University’s School of Engineering for the academic year 2011 - 2012, Simons visiting faculty at the National Centre for Biological Sciences, India in summer 2013, and is a visiting Staff Associate with ICTP, Italy starting 2018. Mahesh’s primary research interests lie in the nonlinear and non-equilibrium physics of complex systems with current focus on interfacial fluid dynamics, mechanics of disordered granular solids, fluctuations in renewable energy, and Biomechanics.

March 27

David L. McDowell, Carter N. Paden Jr. Distinguished Chair in Metals Processing and Regents' Professor of Mechanics of Materials, Georgia Institute of Technology

"Microstructure-sensitive Multiscale Crystal Plasticity Modeling"

Abstract:

Crystal plasticity models are useful for considering the influence of anisotropy of elastic and plastic deformation on local and global responses in crystals and polycrystals. This talk considers multiple crystal plasticity model constructs to address evolution of dislocation structures over a broad range of length and time scales. The utility of crystal plasticity in applications for strain rates ranging from quasistatic fatigue under cyclic loading to shock wave propagation in heterogeneous polycrystalline metals. Emphasis is placed on the forms of the internal state variable structure of the models, with dislocation and other defect densities as a basis. Given its mesoscale character, contrasts are drawn between bottom-up (simulations and experimental observations) and top-down (experimental) information in assembling the constitutive relations and informing their parameters. Alternative forms of bottom-up crystal plasticity models are considered that are sensitive to structure of interfaces and lattices, including adaptive quasi-continuum and concurrent atomistic-continuum methods.

Bio:

Regents’ Professor and Carter N. Paden, Jr. Distinguished Chair in Metals Processing, Dave McDowell joined Georgia Tech in 1983 and holds appointments in both the GWW School of Mechanical Engineering and the School of Materials Science and Engineering. He served as Director of the Mechanical Properties Research Laboratory from 1992-2012. In August 2012 he was named Founding Director of the Institute for Materials (IMat), a Georgia Tech interdisciplinary research institute charged with cultivating cross-cuttting collaborations in materials research and education. IMat (see http://www.materials.gatech.edu) has initiatives in both campus materials user facilities and in accelerating materials discovery and development by building on materials data science and informatics approaches.

McDowell's research focuses on the development of physically-based, microstructure-sensitive constitutive models for nonlinear and time-dependent behavior of materials, with emphasis on wrought and cast metals. Topics of interest include finite strain inelasticity and defect field mechanics, microstructure-sensitive computational approaches to deformation and damage of heterogeneous materials, with emphasis on metal fatigue, atomistic and coarse-grained atomistic simulations of dislocations, dynamic deformation and failure of materials, irradiation effects on materials, and multiscale modeling. He has contributed to schemes for computational materials science and mechanics to inform systems design of materials (Integrated Design of Multiscale, Multifunctional Materials and Products, Elsevier, 2009, ISBN-13: 978-1-85617-662-0). Applications of current interest span lightweight structural materials, materials for hot sections of aircraft gas turbine engines, titanium alloys, armor and blast resistant systems, irradiated ferritic and austenitic alloys, and nanocrystalline materials, among others. McDowell currently serves on the editorial boards of the International Journal of Plasticity, npg Computational Materials, and several other journals. He is co-Editor of the International Journal of Fatigue.

March 29 (Thursday): JOINT ESE-MEAM SEMINAR

Marc Miskin, Kavli Institute Postdoctoral Fellow in Nanoscale Science, Cornell University

"Making Machines the Size of Cells"

11:00 a.m., Room 337, Towne Building

Abstract:

This talk outlines a new approach for fabricating cell-sized machines that can freely explore space, interact with their environment, be manufactured en masse, and carry the full power of modern information technology. We start by identifying origami inspired fabrication as a scalable approach to building 3D machines, and miniaturize to the ultimate limit of folding atomically thin sheets. To do so, we turn atomically thin materials, like graphene, into actuators capable of bending elastically to micron radii of curvature. By patterning rigid panels on top of these actuators, we can localize bending to produce folds, and scale down existing origami patterns to produce a wide range of machines. These machines change shape in fractions of a second in response to environmental changes, can carry a range of electronic, chemical, and photonics payloads, and perform useful functions on time and length scales comparable to microscale biological organisms. Beyond simple stimuli, we demonstrate how to fabricate voltage responsive actuators that can be powered with onboard photovoltaics. Finally, we demonstrate that these mechanical technologies can be combined with silicon-based electronics, moving towards a complete platform for autonomous robotics at the cellular scale.

Bio:

Marc Miskin is a Kavli Institute Postdoctoral Fellow in Nanoscale Science at Cornell. His work centers on building cell-sized structures and machines by folding atomically thin sheets of paper. He has been at Cornell since receiving his PhD in physics from the University of Chicago in 2014. His work has won several awards including a Springer Thesis Award and the Grainger Fellowship for excellence in experimental physics, and has been featured in media outlets including Newsweek, Nova Magazine, and Cosmos. Outside of research, he is actively involved in public science education, frequently appearing as a presenter at the local children's science museum.

April 3: JOINT MSE-MEAM SEMINAR

Tim Rupert, Associate Professor of Mechanical and Aerospace Engineering, University of California at Irvine

"Promoting Beneficial Grain Boundary Phase Transitions with Segregation Engineering"

Abstract:

Doped interfaces can have intriguing structures and, in some cases, thermodynamically-stable interfacial states can form. In this talk, we explore the usage of these “complexions” in nanostructured metal alloys, with a focus on how these features can be used to solve long-standing challenges concerning limited ductility and thermal stability. Atomistic simulations are used to identify the effects of chemistry, temperature, and boundary character on grain boundary structural transitions, as well as identify how these features impact plasticity and fracture. Experimental validation is provided by high resolution transmission electron microscopy on specially-designed thin film samples that systematically explore these variables, as well as nanocrystalline alloys produced through powder metallurgy. Micron-scale experiments are then used to quantify the effect of doping on mechanical behavior, showing that strength, strain-to-failure, and failure mode can be controlled with the addition of segregating dopants. Finally, we will discuss how similar features can improve the fabrication and radiation tolerance of nanostructured metals. As a whole, this work lays the foundation for engineering internal interfaces to design better materials.

Bio:

Prof. Tim Rupert is an Associate Professor of Mechanical and Aerospace Engineering at the University of California, Irvine, with a joint appointment in Chemical Engineering and Materials Science. He received a B.S./M.S. in Mechanical Engineering from Johns Hopkins University in 2007 and a Ph.D. in Materials Science and Engineering from MIT in 2011. Prof. Rupert’s research focuses on uncovering new structure-property relationships in nanomaterials for structural and energy applications, as well as increasing the reliability and lifetime of these materials. To achieve their research goals, his lab uses a combination of experimental, characterization, and computational techniques. In recent years, Prof. Rupert has received an NSF CAREER Award, a DOE Early Career Research Program Award, an ARO Young Investigator Program Award, a Hellman Fellowship, and the ASM International Bradley Stoughton Award for Young Teachers. He serves on the editorial boards of Materials Science and Engineering A, Metallurgical and Materials Transactions A, and Scientific Reports.

 

April 5 (Thursday): MEAM SPECIAL SEMINAR

Yufeng (Kevin) Chen, Postdoctoral Fellow, Harvard Microrobotics Laboratory

"Multimodal and Multiphase Locomotion in Biologically Inspired, Insect-scale Robots"

1:30 p.m., Glandt Forum, Singh Center for Nanotechnology

Abstract:

Several insect species, such as diving flies and diving beetles, exhibit remarkable locomotive capabilities in aerial, aquatic, and terrestrial environments, and they inspire the development of similar capabilities in robots at the centimeter scale. In this talk I will present two insect-scale robots capable of multimodal and multiphase locomotion. I will start by presenting a 175mg, flapping wing robot that can hover in air, swim underwater, and impulsively jump out of the water surface through combustion. Experimental and computational studies of flapping wing flight not only improve the vehicle payload and efficiency, but also enable hybrid locomotion in different fluids by modifying the flapping strategies. I will also introduce a 1.6g, quadrupedal robot capable of locomotion on land, on the surface of water, underwater, and between these environments. This robot utilizes electrowetting to modify the surface tension force, which either supports the robot on the surface of water or facilitates controllable transition into water. These results demonstrate that microrobots can achieve novel functions that are absent in larger, traditional robots, thereby showing the unique potential of microrobots in applications such as search-and-rescue and environmental exploration in cluttered spaces.

Bio:

Kevin Chen is a postdoctoral fellow at the Harvard Microrobotics Laboratory. He received his PhD in Mechanical Engineering at Harvard University under the supervision of Professor Robert J. Wood. His work focuses on developing insect-scale robots capable of locomotion and transition between different environments such as air, water, water surface, and ground. His research interests also include investigating mesoscale physics associated with microrobotic systems, such as low Reynolds number flapping wing flight and electrowetting. Kevin received his Bachelor’s degree in Applied and Engineering Physics from Cornell University. He is a recipient of the best student paper award at the International Conference on Intelligent Robots and Systems (IROS) 2015 and a Harvard Teaching Excellence Award.

April 9 (Monday): MEAM Ph.D. Thesis Defense

Chen Lin, Ph.D. Candidate, University of Pennsylvania
Advisor: Igor Bargatin

10:30 a.m., Room 307, Levine Hall

"Microstructures and Mechanical Metamaterials for Energy Conversion and Other Applications"

Abstract:

Mechanical metamaterials, a novel class of cellular solids, have recently received much attention since they provide an innovative path to the realization of materials with both low density and high stiffness. They typically have carefully architected periodic structures at the micro/nano-scale, which have unique mechanical properties defined by their architecture instead of their composition. Past research has concentrated on the architectural designs (e.g. bending-dominated and stretching-dominated), fabrication techniques (e.g. self-propagating photopolymer waveguide, direct write lithography and printing, and self-assembly) and mechanical characterizations (e.g. stiffness, strength, and recoverability) of three-dimensional truss-like bulk mechanical metamaterials. Their underlying parent material creates an interconnected periodic structure which can be easily penetrated by gas. In contrast, we recently proposed the concept of plate mechanical metamaterials, which are cellular plates with carefully engineered and tightly controlled periodic architectures. Standard micro/nano-fabrication processes were developed to fabricate ultra-lightweight, stiff, robust, flat and scalable single/two-layer continuous plates and nanocardboard hollow sandwich plates out of ultrathin insulating alumina films formed by atomic layer deposition. These standard optical lithography based fabrication techniques enable the mass production of these plate mechanical metamaterials by generally patterning nearly arbitrary geometry in the vertical direction of a plate. Similar to the shape-recovering property of bulk mechanical metamaterials under large shear or compression deformations, the plate mechanical metamaterials could recover their original shapes after extreme bending deformations, which is explained by the elastic shell buckling of ultrathin features. A nanocardboard sandwich plate—analog of corrugated cardboard—with nanoscale plate thickness, microscale plate height and macroscale lateral dimensions was first made which can achieve the highest ratio of bending stiffness to areal density, outperforming all other reported materials. These plate mechanical metamaterials can be potentially used in many fields, such as serving as the spacer in a high-efficiency thermionic energy converter. The thermal and mechanical properties of the spacers were characterized, and showed excellent thermal insulation and mechanical robustness.

 

April 10

Evelyn Wang, Gail E. Kendall Professor of Mechanical Engineering, Massachusetts Institute of Technology

"Nanoengineered Structures for Advanced Energy and Water Technologies"

Abstract:

Nanoengineered structures and materials have exciting, untapped potential to improve energy and water technologies. In this talk, I provide a few examples of how we leverage nanoscale manipulation capabilities to develop advanced thermal management, solar thermal energy conversion and water harvesting devices. First, I discuss our recent work that harnesses novel surface designs to control and manipulate phase-change processes. Low surface tension condensates pose a unique challenge since they often form a film, even on hydrophobic coatings. Lubricant infused surfaces (LIS) represent a potential solution, where a lubricant immiscible with the low surface tension condensate is infused into a rough structure on the condenser surface to repel the condensate. We used LIS to demonstrate a 5x improvement in heat transfer for low surface tension fluids compared to filmwise condensation and provide detailed designed guidelines for LIS. Next, I discuss how nanoengineered materials can also be used to increase the efficiency of solar thermal devices. In solar thermophotovoltaics, we show that engineering the spectral properties and defining the active area of the emitter with respect to the absorber, we achieve solar-to-electrical conversion efficiencies of 6.8%, exceeding that of the underlying cell. Finally, I discuss a new water harvesting device that takes advantage of the unique properties of metal organic frameworks to address water scarcity challenges in arid climates.

Bio:

Evelyn N. Wang is the Gail E. Kendall Professor and the Associate Department Head in the Mechanical Engineering Department at MIT. She is the Associate Director of the Solid State Solar Thermal Energy Conversion (S3TEC) Center, a DOE Energy Frontiers Research Center. She received her BS from MIT, and MS and PhD from Stanford University in Mechanical Engineering. From 2006-2007, she was a postdoctoral researcher at Bell Laboratories. Her research interests include fundamental studies of micro/nanoscale heat and mass transport and the development of efficient thermal management, solar thermal energy conversion, and water harvesting systems. Her work has been honored with several awards including the 2012 ASME Bergles-Rohsenow Young Investigator Award, the 2016 ASME EPPD Women Engineer Award, and the 2017 ASME Gustus L. Larson Award. She is an ASME Fellow.

April 12 (Thursday)

Yu Sun, Professor, Department of Mechanical and Industrial Engineering, University of Toronto

1:30 p.m., Raisler Lounge (Towne 225)

"Robotic Manipulation of Cells, Molecules, and Nanomaterials"

Abstract:

The capability of manipulating micro and nanometer-sized objects, such as cells/molecules and nanomaterials opens new frontiers in robotic surgery, disease diagnostics, industrial applications and enables new discoveries in many disciplines such as biology, medicine, and materials science. The past two decades has witnessed spurred development of micro-nano robotic systems and technologies with common hallmarks of precision instrumentation, sensing, actuation, and control. This presentation will first provide a brief overview of challenges, opportunities, and recent advances made in the field of micro-nano robotics. Next, I will introduce our micro-nano robotic and device techniques for realizing a ‘nanofactory’ inside scanning electron microscopes with unique capabilities of automated nanomanipulation and multimodal measurement of nano-scaled materials. I will then discuss our work in robotic cell manipulation, including recent progress in clinical trial of our robotic cell surgery technologies, drug screen for the management of cardiovascular diseases enabled by robotic cell manipulation, and if time permits, robotic characterization of voided urine cells to bolster clinical bladder cancer diagnostics. I will end the talk by sharing our most recent activities that shift the paradigm of robotic cell manipulation from single-cell manipulation to intracellular navigation and measurement.

Bio:

Yu Sun is a Professor in the Department of Mechanical and Industrial Engineering, with joint appointments in the Institute of Biomaterials and Biomedical Engineering and the Department of Electrical and Computer Engineering at the University of Toronto. He was elected Fellow of ASME (American Society of Mechanical Engineers), IEEE (Institute of Electrical and Electronics Engineers), AAAS (American Association for the Advancement of Science), and CAE (Canadian Academy of Engineering) for his work on micro-nano devices and robotic systems. His Advanced Micro and Nanosystems Laboratory specializes in developing innovative technologies and instruments for manipulating and characterization of cells, molecules, and nanomaterials, and collaborates with an extensive collaborative network that includes clinician scientists, industry partners, biologists, physicists, material scientists, and engineers.

Sun obtained his Ph.D. from the University of Minnesota in 2003 and did his postdoctoral research at ETH-Zürich. He is presently a McLean Senior Faculty Fellow at the University of Toronto and a Tier I Canada Research Chair. In 2012-2013, he directed the University of Toronto Nanofabrication Center. Sun has served and serves on the editorial boards of several IEEE journals (IEEE Trans. Robotics, IEEE Trans. Automation Science and Engineering, and IEEE Trans. Mechatronics), J. Micromechanics Microengineering, Scientific Reports, and Microsystems & Nanoengineering. Among the awards he received were the IEEE Robotics and Automation Society Early Career Award; a dozen best paper awards and finalists at major conferences; six times University of Toronto Connaught Innovation Award; the McLean Award; the First Prize in Technical Achievement of ASRM (American Society for Reproductive Medicine); an NSERC E.W.R. Steacie Memorial Fellowship; and the IEEE C.C. Gotlieb Computer Award.


April 17

Nikolas Martelaro, Ph.D. Candidate, Center for Design Research, Stanford University

“The Needfinding Machine: Understanding Users with Interactive Devices and Designers in the Loop”

Abstract:

Interactive physical systems present new opportunities for creating products that satisfy people's needs. These opportunities require designers and engineers to anticipate how future products such as autonomous cars, personal robots, and digital assistants will interact with users. In this presentation, I will discuss the Needfinding Machine, a method that lets designers use interactive devices to do remote user observation, interaction prototyping, and needfinding from anywhere with a network connection. I show two collaborations with practicing designers who used the Needfinding Machine to understand the interaction design needs for autonomous systems; 1) engineers and designers at Renault exploring currently available advanced driving assistance features and 2) human-agent interaction researchers at Spotify exploring in-car music assistants. I also discuss a current project focused on gathering real-world user-centered data for developing appropriate speech interaction for in-car agents. By observing and understanding people's lived experience, designers and engineers can create better interactions with future autonomous systems.

Bio:

Nik Martelaro is a Ph.D. candidate in Mechanical Engineering at Stanford’s Center for Design Research. His work looks at how to design, build, and test systems that help designers create human-centered interactive physical products. He collaborates with industry designers to understand how new tools and methods improve design practice. Nik blends a hands-on background building steam engines, Baja cars, robotic furniture, and interactive device prototyping systems with a focus on understanding what makes for great interaction with everyday intelligent products.

April 23 (Monday): MEAM-ESE SPECIAL SEMINAR

Cunjiang Yu, Bill D. Cook Assistant Professor, Department of Mechanical Engineering, University of Houston

11:00 a.m., Raisler Lounge, Towne 225

"Manufacturing, Materials, and Device Innovations for Soft and Curvy Electronics "

Abstract:

Innovative manufacturing technologies and materials are critical in building next-generation electronics devices, especially when we are migrating from conventional electronics to emerging electronics with unique form factors, such as those flexible, stretchable and wearable and curvilinear electronics, which hold promise in a broad range of areas such as healthcare, robotics, human-machine interfaces, etc.
In this talk, I will present some of our recent research progress on manufacturing, materials, and device innovation for stretchy and curvy electronics. Existing strategies to enable mechanical stretchability in soft electronics heavily rely on special mechanical architectures, which impose a heavy burden on sophisticated fabrication and associated cost. I will show our recent results on developing a completely new set of stretchable electronics, namely “fully rubbery electronics”. Fully rubbery electronics are constructed completely based on elastomeric electronic materials and therefore intrinsically stretchable. The fully rubbery electronics in thin sheets mimics the format and functionalities of our elastic human skin. I will then show our recent progress on developing 3D curvilinear electronics, a class of overlooked electronics with 3D curvilinear form factors. A new manufacturing approach, namely conformal additive transfer printing, will be presented. Different type of 3D curvilinear devices such as smart contact lenses with integrated sensors and electronics for multi-functionalities will be demonstrated.

Bio:

Dr. Cunjiang Yu is the Bill D. Cook Assistant Professor of Mechanical Engineering at the University of Houston, with joint appointments in Electrical and Computer Engineering, Materials Science and Engineering, and Biomedical Engineering. He got B.S. in Mechanical Engineering and M.S. Electrical Engineering in 2004 and 2007, respectively, from Southeast University, Nanjing, China. He then received his Ph.D. in Mechanical Engineering at Arizona State University in 2010. Following the completion of his PhD, he was trained as a postdoc at the University of Illinois at Urbana-Champaign before joining UH in Oct. 2013. His research focuses on fundamental and application aspects of soft, curvy electronics. His recent research outcomes have been reported or highlighted by many media outlets, such as Time, Discovery, BBC News, NBC News, Science News, USA Today, etc.

He is a recipient of NSF CAREER Award, ONR Young Investigator Award, MIT Technology Review 35 Top Innovators under the age of 35 - TR35 China, ACS Petroleum Research Fund Doctoral New Investigator Award, American Vacuum Society Young Investigator Award, 3M Non-Tenured Faculty Award, UH University level Award of Excellence in Research & Scholarship, UH College of Engineering Junior Faculty Research Excellence Award.

 

April 24

Mark Alan Fogel, Professor of Pediatrics, Children's Hospital of Philadelphia

Title TBA

Abstract:

TBA

Bio:

TBA

April 25 (Wednesday): MEAM SPECIAL SEMINAR

Angela Pitenis, Postdoctoral Associate, The Tribology Laboratory and Soft Matter Engineering Center, University of Florida

11:00 a.m., Towne 337

“Soft Matter Engineering: Cells, Gels, and Shear”

Abstract:

Almost everything in the human body -- excluding teeth and bone -- is soft, squishy, and nearly free-form in geometric construction and structural organization. While soft biological systems (e.g., cells, tissues, and organs) may seem the antithesis of traditional engineering materials, they often carry significant stresses under large strains, perform complex mass and heat transport functions, and continuously remodel and rebuild in response to engineering-like challenges. Soft Matter Engineering is an emerging field that focuses on challenges in the design, manufacturing, and use of structures, assemblies, and devices that are “soft” or interface with “soft matter”. This talk will discuss the development of ultra-low contact pressure instrumentation for probing delicate interfaces during contact and sliding. These instruments were custom-built onto microscope frames to enable in situ optical microscopy and confocal imaging. A wide range of experiments were performed to explore models of hydrogel lubricity based on theories of viscous dissipation within a surface region estimated to be on the order of a single polymer mesh size. The applied focus of this research is towards biocompatibility and comfort in soft contact lenses.

Bio:

Dr. Angela A. Pitenis is a researcher in the Soft Matter Engineering Center in the Department of Mechanical and Aerospace Engineering at the University of Florida. Her research is in interfacial engineering, with a particular focus on soft, biological, and biologically-inspired material systems. Current activities are focused on the tissue and tumor microenvironment, and this research uses contact mechanics, soft condensed matter physics, surface science, and biomedicine. Angela’s work has ranged from exploring the mechanochemistry of fluoropolymer interfaces during sliding, to hydrogel lubricity, to recently uncovering the mechanisms of friction-induced inflammation by gently rubbing hydrogels against human corneal epithelial cells in vitro.

 

April 27 (Friday): MEAM SPECIAL SEMINAR

Zdenek P. Bazant, McCormick Institute Professor and Walter P. Murphy Professor of Civil and Environmental Engineering, Mechanical Engineering and Material Science and Engineering, Northwestern University

4:00 p.m., LRSM Auditorium

"Design of New Materials and Structures to Maximize Strength at Probability Tail: A Neglected Challenge for Quasibrittle and Biomimetic Materials"

Abstract:

In developing new materials, the research objective has been to maximize the mean strength (or fracture energy) of material or structure and minimize the coefficient of variation. However, for engineering structures such as airframes, bridges of microelectronic devices, the objective should be to maximize the tail probability strength, which is defined as the strength corresponding to failure probability 10-6 per lifetime. Optimizing the strength and coefficient of variation does not guarantee it. The ratio of the distance of the tail point from the mean strength to the standard deviation depends on the architecture and microstructure of the material (governing the safety factor) is what should also be minimized. For the Gaussian and Weibull distributions of strength, the only ones known up to the 1980s, this ratio differs by almost 2:1. For the strength distributions of quasibrittle materials, it can be anywhere in between, depending on material architecture and structure size. These materials, characterized by a nonnegligible size of the fracture process zone, include concretes, rocks, tough ceramics, fiber composites, stiff soils, sea ice, snow slabs, rigid foams, bone, dental materials, many bio-materials and most materials on the micrometer scale. A theory to deduce the strength distribution tail from atomistic crack jumps and Kramer’s rule of transition rate theory, and determine analytically the multiscale transition to the representative volume element (RVE) of material, is briefly reviewed. The strength distribution of quasibrittle particulate or fibrous materials, whose size is proportional to the number of RVEs, is obtained from the weakest-link chain with a finite number of links, and is characterized by a Gauss-Weibull grafted distribution. Close agreement with the observed strength histograms and size effect curves are demonstrated. Discussion then turns to new results on biomimetic imbricated (or scattered) lamellar systems, exemplified by nacre, whose mean strength exceeds the strength of constituents by an order of magnitude. The nacreous quasibrittle material is simplified as a fishnet pulled diagonally, which is shown to be amenable to an analytical solution of the strength probability distribution. The solution is verified by million Monte-Carlo simulations for each of fishnets of various shapes and sizes. In addition to the weakest-link model and the fiber-bundle model, the fishnet is shown to be the third strength probability model that is amenable to an analytical solution. It is found that, aside from its well-known benefit for the mean strength, the nacreous microstructure provides a significant additional strengthening at the strength probability tail. Finally it is emphasized that the most important consequence of the quasibrittleness, and also the most effective way of calibrating the tail, is the size effect on mean structural strength.

Bio:

Born and educated in Prague (Ph.D. 1963), Bažant joined Northwestern in 1969, where he has been W.P. Murphy Professor since 1990 and simultaneously McCormick Institute Professor since 2002, and Director of Center for Geomaterials (1981-87). He was inducted to NAS, NAE, Am. Acad. of Arts & Sci., Royal Soc. London; to the academies of Italy (lincei), Austria, Spain, Czech Rep., India.and Lombardy; to Academia Europaea, Eur. Acad. of Sci. & Arts. Honorary Member of: ASCE, ASME, ACI, RILEM; received 7 honorary doctorates (Prague, Karlsruhe, Colorado, Milan, Lyon, Vienna, Ohio State); Austrian Cross of Honor for Science and Art 1st Class from President of Austria; ASME Timoshenko, Nadai and Warner Medals; ASCE von Karman, Newmark, Biot, Mindlin and Croes Medals and Lifetime Achievement Award; SES Prager Medal; RILEM L’Hermite Medal; Exner Medal (Austria); Torroja Medal (Madrid); etc. He authored seven books: Scaling of Structural Strength, Inelastic Analysis, Fracture & Size Effect, Stability of Structures, Concrete at High Temperatures, Concrete Creep and Probabilistic Quasibrittle Srength. H-index: 119, citations: 62,500 (on Google Feb..2018, incl. self-cit.), i10 index: 565. In 2015, ASCE established ZP Bažant Medal for Failure and Damage Prevention. He is one of the original top 100 ISI Highly Cited Scientists in Engrg. (www.ISIhighlycited.com). His 1959 mass-produced patent of safety ski binding is exhibited in New England Ski Museum.