http://s.uconn.edu/meseminar05.13.22

Abstract: In this seminar, Changjie will give an overview of GE Research first, followed by discussion of additive manufacturing. On the additive manufacturing, he will cover additive designs, additive digital tools, additive process monitoring and control, additive supply chain, and additive applications. He welcomes any individual discussions after the seminar.

Biographical Sketch: Changjie Sun has a Ph.D. in Mechanical Engineering. He is currently a senior principal engineer in the Materials and Mechanical Systems Organization at GE Research. He is the technical focal for structure design/analysis and mechanical synthesis. He has been working on jet engine and gas turbine design and analysis for 16 years involving metals, polymer matrix composites, and ceramic matrix composites. Changjie is active in seeking funding opportunities from funding agencies such as DOE and DOD.

http://s.uconn.edu/meseminar05.06.22

Abstract: In this overview of the Engineering Design & Systems Engineering (EDSE) Program at the National Science Foundation, NSF Program Director Kathryn Jablokow will highlight core themes of the program and new opportunities relevant to the engineering design and systems design communities, along with a few key principles for successful proposal writing. In addition, she will discuss her vision for design research, including the implications of treating design as a system and the prospects that open up when we take things to extremes.

Biographical Sketch: Dr. Kathryn Jablokow is a Professor of Engineering Design and Mechanical Engineering at Penn State University and currently serves the National Science Foundation in the Civil, Mechanical and Manufacturing Innovation Division as Program Director for the Engineering Design and Systems Engineering program. Dr. Jablokow is widely recognized for her expertise in cognitive diversity and its impact in engineering education and practice, including manufacturing education and student design experiences. Her recent research includes the use of rapid manufacturability analysis tools to enhance decision-making in engineering design education, as well as the characterization and mediation of manufacturing fixation in design education and practice (i.e., interventions to address an engineer’s overreliance on a specific manufacturing technique). Dr. Jablokow has received many major teaching and research awards, including the W. M. Keck Foundation Teaching Excellence Award, the American Society of Mechanical Engineers (ASME) Ruth and Joel Spira Outstanding Design Educator Award, and multiple Best Paper Awards. Dr. Jablokow is a Fellow of ASME, a Senior Member of IEEE, and a Member of ASEE, Sigma Xi, and the Design Society. She earned her BS, MS, and PhD degrees in electrical engineering from The Ohio State University in 1983, 1985, and 1989, respectively.

http://s.uconn.edu/meseminar04.29.22

Abstract: Implantable Brain Computer Interfaces appear to be heading towards an inflection point: in the past decade the number and frequency of major technological advances and first in human demonstrations of new capabilities has started increasing significantly. The first generations of commercially available products appear to be imminent. They have the potential to become tangible tools to restore lost function and are serious contenders to address a variety of neurological disorders. The real life settings associated with in home use of these technologies lead to reprioritization of existing as well as the emergence of novel practical and fundamental challenges and opportunities. How do we identify and prioritize user, clinician and caretaker needs? What is possible today and what is a realistic technological roadmap that meets those needs. What should public and private investments be focused on?

Biographical Sketch: Dr. Solzbacher is Professor and Chair of the Department of Electrical and Computer Engineering. He also holds adjunct appointments as Professor in Materials Science and Professor of Biomedical Engineering at the University of Utah. He is a fellow of the American Institute for Medical and Biological Engineers AIMBE and a Fellow of the Institute of Electrical and Electronics Engineers IEEE. He is Co-Founder, President and Executive Chairman of Blackrock Microsystems/Neurotech. His research focuses on harsh environment microsystems and materials, including implantable, wireless microsystems for biomedical and healthcare applications, and on high temperature and harsh environment compatible micro sensors. He is co-founder of several companies and member of a number of company and public private partnership advisory and reviewer boards and conference steering committees in Europe and the US. He is author of over 190 journal and conference publications, 5 book chapters and 16 pending patents.

http://s.uconn.edu/meseminar4.22.22

Abstract: Meta-structures are artificially engineered structures designed to exhibit properties not found in conventional materials. By careful design, one can obtain unprecedented control over various physical properties. Examples in mechanics includes structures having unique static and dynamic properties like negative Poisson’s ratio, zero shear modulus and non-reciprocal wave propagation. 

Waveguides transporting energy and information are widely used in bulk and surface acoustic wave devices. They have stringent requirements of a dispersion bandgap and suffer from losses due to localization and scattering at defects or imperfections. In this talk, I will illustrate how these limitations can be overcome by a new class of meta-structures: symmetry protected waveguides. Inspired by recent developments in quantum condensed matter physics, such waveguides allow for wave propagation along an interface or boundary, immune to the presence of structural defects. I will present three examples of different classes of such waveguides. The first example will show a general design paradigm to localize energy in a structure at a desired frequency, while the second and third examples will illustrate backscattering free wave guiding and wave propagation along a channel in structures without any bandgaps. Such waveguides have potential applications in acoustic signal processing, imaging and vibration isolation..

 

Biographical Sketch: Raj Kumar Pal received his bachelor’s degree in mechanical engineering from the National Institute of Technology, Trichy, India, followed by his master’s degree in the same field from the Indian Institute of Science, Bangalore, India. He then worked in industry for a year before starting doctoral graduate studies at the University of Illinois, Urbana Champaign. He earned a Ph.D. in Theoretical and Applied Mechanics, followed by postdoctoral appointments in the School of Aerospace Engineering, Georgia Institute of Technology, and in the mechanical and civil engineering department at the California Institute of Technology. Since 2019, he is an Assistant Professor in the mechanical and nuclear engineering department at Kansas State University. He works broadly at the intersection of solid mechanics and dynamics, investigating fundamental wave propagation phenomena with the goal of novel engineering applications. 

http://s.uconn.edu/meseminar04.01.22

Abstract: Matter (https://www.cell.com/matter) is a new materials science journal from Cell Press (our first issue was July ‘19). Matter is the third offering in the physical sciences from Cell Press, after the successful launches of Chem (2016) and Joule (2017), and an expanding physical sciences portfolio. Our goal is to provide a high impact publication in the field on par with Nature Materials. In this talk, the editor-in-chief, Steve Cranford, will outline the aims and scope of Matter, our internal scientific editorial team, describe our assessment process and outline our framing of materials science. We present our novel MAP scale for materials research progress assessment and provide tips in writing high impact papers and common pitfalls. Come learn about physical sciences at Cell Press and Matter!

Bio: A graduate from Memorial University (Canada), Stanford University (USA), and Massachusetts Institute of Technology (USA), Dr. Cranford was faculty at Northeastern University’s College of Engineering prior to accepting a new role as editor-in-chief for Matter. He has over 50 publications in the field of materials sciences in a range of high impact journals, including Nature and Advanced Materials, with expertise in the area of atomistic simulation, computational modeling, and nanomechanics, encompassing a variety of materials systems, from carbyne to copper to concrete. He would have preferred to have published in Matter, but it didn’t exist. Jumping to publishing in 2018, his goal is to not only make Matter a high impact title in materials science, but also be a key thought leader in academic publishing.

http://s.uconn.edu/meseminar4.8.22

Abstract: Overcoming endemic limitations of existing manufacturing processes can have long lasting socio-economic impacts. I will focus on three innovations that have such an impact. First, I will discuss our work on Intense Pulsed Light Sintering of nanoparticles. I will show how this process alleviates the scalability, damage, and device performance limitations that plague state-of-the-art approaches for manufacturing planar, flexible, conformal, and structural electronics. I will also discuss our discovery of an inherent self-damping behavior in the process, unexpected shape-dependent dynamics of nanoparticle sintering, and the first atomistics-informed scalable model of sintering in nanowire ensembles.

Secondly, I will describe a recent breakthrough in overcoming the throughput-resolution tradeoff that plagues material extrusion-based additive manufacturing (MatEx). I will show how coupling a new toolpath approach with our discovery of continuous material retraction and advancement breaks the above tradeoff, while enhancing economical access to diverse part sizes and geometries and enabling unprecedented resilience to tool failure. I will discuss key parametric trends in the process, new thermal models that reveal the unique temperature history, and potential collaborations with researchers in design and synthesis of materials and in machine learning based control.

Finally, I will describe a magnetics-controlled-plasma based approach to laser micromachining that goes beyond the limits of optical diffraction or wavelength specific-material absorption without modifying the substrate or using near-field techniques. I will discuss key considerations for machine design and process design; the wide materials capability of the process; and the potential to build collaborations in machine learning, control, and process monitoring.

Biographical Sketch: Dr. Rajiv Malhotra obtained his PhD in Mechanical Engineering from Northwestern University and joined Oregon State University as an assistant professor in 2014. He has been an assistant professor at Rutgers University since 2017 where he has established the Advanced Manufacturing Sciences Laboratory, funded by both federal and industry sources. His work has yielded 73 publications including in diverse journals such as Journal of Materials Processing Technology, Journal of Manufacturing Processes, Applied Materials and Interfaces, Advanced Functional Materials, Additive Manufacturing, Nanotechnology, and Sustainable Energy and Fuels. He has been a guest-editor for special issues in ASME and SME journals and is currently an associate editor for Manufacturing Letters, Journal of Manufacturing Processes, and Nature Scientific Reports. He is also a track chair in the ASME Manufacturing Science and Engineering Conference and a scientific committee member in the North American Manufacturing Research Conference. His research and service efforts were recognized by the 2017 Young Manufacturing Engineer Award from the Society of Manufacturing Engineers and the 2018 Associate Editor of the Year Award from the Society of Manufacturing Engineers. Dr. Malhotra is also passionate about integrating sustained mentorship with challenging research opportunities to create a systemic pipeline of students from the undergraduate to the graduate levels.

http://s.uconn.edu/meseminar4.15.22

Abstract: Two-phase internal flows in microgaps with passage hydraulic diameters of 100 um – 1,000 um are of interest in three-dimensional heterogeneous electronics, transport electrification, and portable microsystems.  To enhance heat transfer coefficients in these configurations, structured surfaces are often employed.  Understanding of two-phase flow and thermal transport in such configurations continues to be an active area of research.  This talk will present recent computational and experimental results from investigations of two-phase forced convection, capillary assisted transport, and capillary flow driven passive transport in structured microgaps.  Experimental results include the use of high speed visualizations to elucidate flow regimes, and temperature measurements for heat transfer characterization.  Computations of two-phase flows have been performed using the volume of fluid approach.  While many challenges remain, experimentally validated modeling of such two-phase flows presents a promising approach for understanding the thermal transport in these configurations, and employing them in thermal management in emerging applications.

Biographical Sketch: Yogendra Joshi is Professor and John M. McKenney and Warren D. Shiver Distinguished Chair at the G.W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology.  His research interests are in multi-scale thermal management.  He is the author or co-author of nearly four hundred and fifty publications in this area, including nearly two hundred journal articles. He received his B. Tech. in Mechanical Engineering from the Indian Institute of Technology (Kanpur) in 1979, M.S. in Mechanical Engineering from the State University of New York at Buffalo in 1981, and Ph.D. in Mechanical Engineering and Applied Mechanics, from the University of Pennsylvania in 1984.  He has held visiting faculty appointments at Stanford University, Katholieke Universiteit Leuven, and Xi’an Jiaotong University.  He is an elected Fellow of the ASME, the American Association for the Advancement of Science, and IEEE. He was a co-recipient of ASME Curriculum Innovation Award (1999), Inventor Recognition Award from the Semiconductor Research Corporation (2001), the ASME Electronic and Photonic Packaging Division Outstanding Contribution Award in Thermal Management (2006), ASME J. of Electronics Packaging Best Paper of the Year Award (2008), IBM Faculty Award (2008), IEEE SemiTherm Significant Contributor Award (2009), IIT Kanpur Distinguished Alumnus Award (2011), ASME InterPack Achievement Award (2011), ITherm Achievement Award (2012), ASME Heat Transfer Memorial Award (2013), and AIChE Donald Q. Kern Award (2018).

http://s.uconn.edu/meseminar3/11/22

Abstract: The extracellular matrix (ECM) guides cells through mechanical and soluble signals among others. We guide cell behaviors using these two aspects of ECM.  Even the bone ECM is soft after de-mineralization. Thus, we are interested in soft polymeric materials. Many tissues in our body are elastic including blood vessels, our target tissue. We design elastomers for vascular grafts. The hosts transform the degradable grafts into autologous vascular conduits within a few months, performing the duties of a native artery. On soluble factors, we mimic the anchorage of cytokines in the ECM with heparin-based coacervate. The coacervate extends the bioactivity of many cytokines and growth factors. This controlled release platform shows promise in promoting angiogenesis and controlling immune activities. We are currently exploring how these materials perform in preclinical models, with robust rodent data and early large animal data.

Biographical Sketch: Yadong Wang is the McAdam Family Foundation Professor of Heart Assist Technology at Cornell University. He obtained his Ph.D. degree at Stanford University in 1999, performed his postdoctoral studies at MIT, and joined the Georgia Institute of Technology in 2003 as an assistant professor. He was recruited to University of Pittsburgh in 2008 and subsequently to Cornell in 2017. He has published on topics ranging from Chemistry, Materials Science to Biomedical Engineering in journals including Science, Nature Biotechnology, Nature Medicine, and PNAS.  Several of his inventions are licensed, one polymer he invented is now commercially available and approved for clinical use. He co-founded three companies to translate the technologies developed in his laboratory. His research focuses on creating biomaterials for unmet clinical needs in soft tissues. His team enjoys collaboration with others who share the same passion for translational research.

http://s.uconn.edu/meseminar2/25/22

Abstract: Energy conversion and propulsion systems operating with a lean, premixed mode of combustion are advantageous in terms of both emissions and economics. This is because fully premixing fuel and oxidizer prior to combustion can reduce harmful exhaust levels, while operating fuel lean ensures complete fuel consumption, providing superior fuel economy. In fact, it is often preferred to operate a system as lean as possible; however, there is a limit to how little fuel must be added to a system to facilitate self-sustained combustion. This limit is termed lean blow off (LBO). One mechanism for avoiding LBO is to generate a recirculating flow, which provides 1) a low-velocity region for flames to reside in, and 2) a constant ignition source for the injected reactants. Flow obstructions, like bluff bodies, are often used to produce such recirculating flows. While the LBO limits of premixed bluff-body stabilized flames have been extensively explored, such studies have primarily considered flames operating at atmospheric pressures. Yet, most combustion systems operate at elevated pressures. Thus, there is a need to assess the influence of elevated pressure on the LBO limits of turbulent premixed bluff-body stabilized flames.

This work addresses that need by measuring the LBO limits of such flames while they were operated within an optically accessible pressure chamber. In this study, the operating pressures and bulk flow velocities (U) ranged between 1 and 3 bar and 5 and 50 m/s, respectively. Key observations included the discovery of two stability regimes: one at atmospheric conditions and those with elevated pressure and U < 20 m/s (regime-a), and another at elevated pressures with U < 20 m/s (regime-b). Flames in regime-a were found to be more stable (i.e., their LBO limits occurred at lower fuel-to-air ratios) than those in regime-b. Yet, within both regimes, the LBO limits were found to be insensitive to operating pressure. To elucidate the reason for these observations, advanced laser-based diagnostics were implemented to probe the flames’ structure and to visualize the turbulent flow fields interacting with them. Ultimately, such results provide a phenomenological explanation for the observed behaviors and highlight the fact that explanations and scaling laws derived from measurements at atmospheric conditions cannot always be extrapolated to those at elevated pressures.

Biographical Sketch: Aaron Skiba is an Aerospace Research Engineer in the Combustion Branch of the Turbine Division at the Air Force Research Laboratory (AFRL) in Dayton, Ohio. His current research efforts focus on the experimental assessment of combustion processes occurring under conditions relevant to practical propulsion systems. Such efforts include fundamental studies of liquid-fueled flames subjected to large turbulences levels, the optimization of advanced optical diagnostics to enable such studies, and the development of algorithms to facilitate fair comparisons between experimental and numerical results.

Prior to joining AFRL, Aaron was a postdoc at the Naval Research Laboratory (NRL) where his research efforts focused on experimental studies high-speed spray flames. Such studies included high-speed (>50 kHz) droplet imaging measurements to assess atomization and breakup processes, as well as coherent anti-Stokes Raman spectroscopy (CARS) to obtain temperature profiles. Additionally, while at NRL, Aaron utilized rotational Raman scattering of H2 to measure the temperature of the exhaust issuing from a micro-thruster that was operated within a large vacuum chamber.

Before his postdoc at NRL, Aaron served as a Research Associate in Professor Epaminondas Mastorakos’ group in the Department of Engineering at the University of Cambridge. There, he was involved in an array of experimental studies that included: 1) assessing the lean blow-off (LBO) limits of turbulent premixed bluff-body stabilized flames with either complex fuels at atmospheric conditions or with simple fuels at elevated pressures; 2) exploring the dynamics of ignition and LBO of premixed flames in a full annular combustor; and 3) employing laser-based imaging techniques to elucidate the effects that turbulence, fuel-type, and dilution levels have on the production and oxidization of soot within model aero-engines.

Aaron received his Bachelors, Masters, and Ph.D. degrees from the Department of Aerospace Engineering at the University of Michigan. During his Ph.D., which was supervised by Professor James F. Driscoll, Aaron studied the effects extreme turbulence levels have on the structure and dynamics of premixed flames. Furthermore, a significant portion of his dissertation research was carried out in collaboration with Dr. Campbell D. Carter at AFRL. During those collaborations, Aaron assisted Dr. Carter with the application of an array of state-of-the-art, laser-based diagnostics to highly turbulent premixed flames, the most notable of which involved the simultaneous acquisition of stereo-PIV data with PLIF images of CH2O and OH at a rate of 20 kHz.

Overall, Aaron’s interests lie in optimizing and utilizing advanced laser-based and imaging diagnostics to understand the fundamental physics of flow-chemistry interactions. Ultimately, this understanding will facilitate the development of accurate yet computationally tractable models for predicting the dynamics of turbulent reacting flows.