February 21-27, 2016 marks Engineers Week. Take this time to step back and consider the amazing things engineers do for our society, and to watch the video below that highlights some of the impressive things going on at UConn Engineering.
Events and Seminars
Analysis of Convection in the Presence of Apparent Slip
Friday, November 6 • 2:30 PM – UTEB, Rm. 175
Analysis of Convection in the Presence of Apparent Slip
Marc Hodes
Associate Professor of Mechanical Engineering Tufts University, Medford, Massachusetts
Abstract: A liquid flowing over a structured surface in the form of, e.g., ridges parallel to the flow, may be suspended in the unwetted (Cassie) state. I will introduce the physical principles and micro/nanotechnology that are exploited to trap a liquid in this state, where the no-slip boundary condition does not apply. This complicates the solution of the Stokes (or Navier-Stokes) equations for the velocity profile as it imposes different types of boundary conditions along the solid-liquid interface and the liquid-gas interface (meniscus). The vast majority of previous research on such flows considered them adiabatic. We study them in the presence of heat transfer, where the thermal energy equation is too subjected to non-standard boundary conditions. We have solved a variety of diffusive “inner” problems in the vicinity of the structures, where a boundary condition that the flow or temperature field is 1-dimensional infinitely far away from the structures may be imposed. These yield expressions for the apparent hydrodynamic and thermal slip lengths that manifest themselves as Robin boundary conditions on the outer problems that span the whole domain, e.g., a parallel plate channel. Additionally, in the outer thermal problems, advection must be considered. I will present our conformal map and convolution theory-based analytical solution to an inner thermal problem that captures the effects of evaporation and condensation along menisci. Then, I will discuss our analytical results for the Nusselt number (Nu) governing an outer thermal problem where arbitrary and asymmetric hydrodynamic and thermal (apparent) slip are imposed on a thermally-developing Couette flow. Nu is in the form of Airy and exponential function-containing infinite series, where the first term corresponds to the thermally-developed flow limit. Lastly, I will discuss our present work on the effects of thermocapillary stress and meniscus curvature on both types of apparent slip lengths.
Biographical Sketch: Marc Hodes received his M.S. in Mechanical Engineering from the University of Minnesota, where he performed research on dielectric liquid cooling of microelectronics. In 1998, he received his Ph.D. in Mechanical Engineering from the Massachusetts Institute of Technology, where his research addressed salt deposition (fouling) in supercritical water oxidation reactors used for the destruction of hazardous organic wastes. After holding a succession of appointments from Postdoctoral Member of Technical Staff to Manager over a 10 year period at Bell Labs, he joined the Mechanical Engineering Department at Tufts University in the Fall of 2008 as an Associate Professor. Professor Hodes’ research interests are in heat and mass transfer and, over the course of his career, four thematic areas have been addressed, i.e., 1) the thermal management of electronics, 2) mass transfer in supercritical fluids, 3) analysis of thermoelectric modules and 4) analysis of convection in the presence of apparent slip. Current research is in two areas. First, analytical solutions for apparent hydrodynamic and thermal slip lengths for liquid flows over diabatic structured surfaces that capture the effects of curvature, thermocapillary stress or evaporation and condensation at menisci are being developed. Secondly, enhanced aircooled heat sinks are being developed by deriving semi-analytical optimization formula for longitudinal-fin geometry heat sinks that capture the effects of non-uniform heat transfer coefficients and by developing manufacturing methods for novel “three-dimensional” geometries. Students conducting research with Professor Hodes enroll in part of all of his 4 course sequence of undergraduate fluid mechanics, undergraduate heat transfer, thermal management of electronics and graduate heat transfer. Since joining Tufts University in the fall of 2008 Professor Hodes’ research has been supported by the Department of Energy, NSF, DARPA, Science Foundation Ireland, the Wittich Energy Sustainability Research Initiation Fund, Tufts University and domestic and foreign industrial partners.
For additional information, please contact Prof. Michael T. Pettes at (860) 486-2855, pettes@engr.uconn.edu or Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu
The Science and Engineering of Developing Reliable Electronic Systems
Friday, October 30 • 2:30 PM – UTEB, Rm. 175
The Science and Engineering of Developing Reliable Electronic Systems
Prof. Abhijit Dasgupta Jeong H. Kim
Professor of Mechanical Engineering Center for Advanced Life Cycle Engineering (CALCE)
University of Maryland, College Park, MD 20742
Abstract: This presentation will focus on some of the interesting lessons learned at the CALCE Center over the past 30 years in the science and technology of material aging mechanisms and system degradation modes in complex electronic systems. Modern engineering systems are becoming extremely electronics-rich where the electronics are intrinsically multi-functional systems with highly multi-physics aging and degradation mechanisms under complex life-cycle environmental and operational stress combinations. At the same time, ever-increasing demands for miniaturization have extended the degradation physics into the nano-to-micro length scales, requiring rigorous multi-scale approaches. A few interesting examples of such multi-physics multi-scale degradation mechanisms include creep-fatigue in high-temperature interconnect metal alloys, ‘cold-welding’ in gold-gold interconnects by solid-state diffusion, leakage currents due to the electro-chemistry of dendritic growth in metallization, and dielectric breakdown due to quantum tunneling effects. This pressure for miniaturization, combined with the need for increased functionality and increased affordability, have placed tremendous pressure on the science and technology of achieving and assuring reliability in complex electronic systems. Conducting this type of application-driven fundamental and applied research in a university setting, within the context of graduate thesis and dissertation research, poses unique challenges and imparts special training and skills to the student researchers, to equip them for a very diverse employment landscape. An overview and a few selected examples will be provided during this presentation, with particular emphasis on important lessons that graduate students can take away on how to prepare for the modern-day multi-disciplinary work-place and research environment.
Biographical Sketch: Dr. Abhijit Dasgupta, Jeong H. Kim Professor of Mechanical Engineering, has been teaching at University of Maryland since he obtained his Ph.D. in Theoretical & Applied Mechanics from the University of Illinois in Urbana-Champaign in 1988. His expertise is in the multi-physics, multi-scale constitutive behavior and damage mechanics of engineered materials, for applications in reliability assessment, for real-time health monitoring, and for accelerated stress testing of electronic/photonic systems, ‘smart’ structures, MEMS, and nanoscale structures. This research is funded by an international consortium of leading electronics manufacturers as well as by government funding agencies as NSF, ARL and ARO. He is an ASME Fellow and the current Chair of the Electronic and Photonics Packaging Division of ASME.
For additional information, please contact Prof. Xinyu Zhao at (860) 486-0241, xinyuz@engr.uconn.edu or Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu
A Quest for the Ideal Solution in engineering design. Five challenges of BTIPS.
Friday, October 23 • 2:30 PM – UTEB, Rm. 175
A Quest for the Ideal Solution in engineering design. Five challenges of BTIPS.
Dr. Zbigniew M. Bzymek, University of Connecticut, Mechanical Engineering
Abstract: The nature of engineering is problem solving. The process starts with the problem definition and is followed by the search of a solution that satisfies the most requirements. Such a solution is an End Solution of the process and it changes into an Ideal Solution which determines the success of the design. So the starting point of the design process is the conceptual solution. Finding the right conceptual solution determines the success of the product. If the concept is not right, even the most sophisticated geometry and the most precise analyses will not lead to a successful product. Evident concepts are not hard to find. The real challenge occurs when engineers have to solve the problem with conflicting constraints that are described by antonyms as for example: “is there and is not there”, “close and far”, “hard and soft” and so on. BTIPS – a Brief Theory of Inventive Problem Solving is a method of conceptual design that is helpful in solving such conflicting constraints. BTIPS originated from Altshuller’s TRIZ1 and Invention Machine TIPS2 . It was developed from these two methods at the University Connecticut by introducing abbreviations, changes and additions based on the newest theoretical and practical achievements of Science and Technology. BTIPS was developed mainly for teaching but it is powerful enough to be applied in engineering practice. BTIPS, similar to IM TIPS, contains three modules: Principles, Effects and Prediction. During the research at UConn three were new principles were added to the PRINCIPLES module, several effects to the EFFECTS module and virtual elements to the PREDICTION module. In the solution process algorithm improvements of the sequence of modules was introduced. To confirm the Ideal Solution two tests of the End Solution were established. Five challenges were also added. as the introduction to BTIPS. The five challenges are: “Solve Impossible”,” Isolate Properly”, “Choose the Right Solution Tool”:”Separate Functions” and “Point the Ideal Solution”. Overcoming all five challenges would allow the designer to accomplish the Quest for the Ideal Solution. TRIZ1 – /ˈtriːz/; Russian: теория решения изобретательских задач, teoriya resheniya izobretatelskikh zadach, literally: “theory of solving of inventive problems”); TIPS2 – Theory of Inventive Problem Solving.
Biographical Sketch: Zbigniew M. Bzymek, Ph.D., Associate Professor of Mechanical Engineering at UConn is a contributor to Design Theory, Designer and Constructor of Structures, Researcher and Educator of Engineers. He has received PhD in 1968, M.Sc. from Warsaw University of Technology in 1959 and M.Sc. from University of Michigan, Ann Arbor, Michigan in 1961. As a result of extensive research in Poland he put together several packages of computer programs for stress and deflection analysis of structures. He has published the first book in Polish on computer analysis of structures (translated to Hungarian), which also was one of the first in Eastern Europe. He has delivered over 50 invited lectures and seminars on the design and CAD of structures at universities, at computational centers as well as in design and consulting offices in Poland, Hungary, Czechoslovakia, Soviet Union, Germany, UK, US, China, Australia, Dubai, Mexico and Canada. He modernized the CAD and Manufacturing Automation courses taught at UConn and developed a CAD &CAM Laboratory – one of the most unique and significant on the East coast. For contribution to computer multicolor, multi-thickness line drawing he was awarded the title of Computer Graphics Pioneer in the United States. He has contributed to the conceptual design by introducing several principles. Together with his students he has received several recognitions and industrial design awards as well as the Second National ASME Design Award. He has published over 150 articles, conference papers, books and chapters. His conference papers were presented in the US, Canada, Japan, Australia, Mexico, New Britain, Poland and other European countries. He is an Associate Member of Engineering Committee of the Polish Academy of Science and Member of the New York Academy of Science. He has been awarded an ASME medal and is an ASME Fellow.
For additional information, please contact Prof. Xinyu Zhao at (860) 486-0241, xinyuz@engr.uconn.edu or Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu
Learning-based High-speed Motion Control: Application to Scanning Probe Microscopy
Friday, October 16 • 2:30 PM – UTEB, Rm. 175
Learning-based High-speed Motion Control: Application to Scanning Probe Microscopy
Prof. Qingze Zou
Rutgers University
Abstract: Iterative learning control (ILC) has demonstrated its superior efficiency, efficacy, and robustness in a broad variety of applications including high-speed, broadband motion control. A fundamental limitation of ILC framework, however, is that the applied operations need to be of repetitive nature with the desired motion (trajectory) fixed and known a priori. As a result, ILC cannot be applied in non-repetitive applications such as probe-based nanomanufacturing and nanomanipulation where the desired trajectory is not completely known a priori. Existing efforts to extend ILCs beyond repetitive operations to general motion control, however, are challenged by the limited applications and limited types of trajectories that can be tracked. In this talk, I will first use scanning probe microscope (SPM) as an example to illustrate a suite of recently-developed inversion-based iterative learning control algorithms in achieving high-speed SPM imaging, rapid broadband nanomechanical quantifications of soft and live biological materials, and high-speed probe-based nanofabrication. Second, I will present our efforts in extending the ILC beyond repetitive applications, by combining offline a priori learning via ILC with online synthesis, first for linear systems, and then for simultaneous hysteresisdynamics compensation in systems such as smart actuators.
Biographical Sketch: Dr. Qingze Zou is an Associate Professor in the Department of Mechanical and Aerospace Engineering of Rutgers, the State University of New Jersey. Priorly he had taught in the mechanical engineering department of Iowa State University. He obtained his Ph.D. in Mechanical Engineering from the University of Washington, Seattle, WA in 2003. His research interests include learning-based output tracking and control, control tools for high-speed scanning probe microscope imaging, probe-based nanomanufacturing, micromachining, and rapid broadband nanomechanical measurement and mapping of soft and live biological materials. He received the NSF CAREER award in 2009, and the O Hugo Schuck Best Paper Award from the American Automatic Control Council in 2010. He is the representative of the IEEE Control Systems Society in the IEEE Nanotechnology Council, a former Associate Editor of ASME Journal of Dynamic Systems, Measurement and Control, and currently a Technical Editor of IEEE/ASME Transactions on Mechatronics.
For additional information, please contact Prof. Xinyu Zhao at (860) 486-0241, xinyuz@engr.uconn.edu or Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu
PV, EV and Your Home: How Transportation and Grid Infrastructures Work Together
Friday, October 9 • 2:30 PM – UTEB, Rm. 175
Joint ME & CBE Seminar
PV, EV and Your Home: How Transportation and Grid Infrastructures Work Together
Dr. James Fenton
Director of Solar Energy Center University of Central Florida
Abstract: There are over 20 models of electric vehicles (EV) (350,000 vehicles on the road) that are so efficient that they cost the gasoline equivalent of $0.99 a gallon to operate, based on the national residential electricity average of 11.88¢/kWh. The levelized cost for residential “rooftop” photovoltaics (PV) in much of the U.S. is the same as the cost of electricity “out of the wall.” PV electricity is at cost parity with grid energy, and gasoline parity is a long distance in the rearview mirror. As prices for solar and EVs continue to decrease, consumer adoption rates for both technologies will increase dramatically, resulting in an integration of solar energy and electric transportation infrastructure. Will we get out in front and surf the wave created by the solar and EV tsunami or will we drown? This presentation will introduce the concepts that allow the transportation and grid infrastructures to work together, so that PV, EVs and energy efficient buildings can significantly decrease our dependency on fossil fuels, mitigate climate change, provide mobile backup power, and increase energy and transportation security. The seminar is largely based on articles that examine EVs, energy efficient homes, photovoltaics, the smart grid and EV charging; published in the Spring 2015 Interface magazine “PV, EV and Your Home” of the Electrochemical Society.
Biographical Sketch: Professor James M. Fenton is the Director of the University of Central Florida’s Florida Solar Energy Center (FSEC), where he leads a staff of 100 in the research and development of energy technologies that enhance Florida’s and the nation’s economy and environment and educate the public, students and practitioners on the results of the research. FSEC leads national programs funded by the U.S. Departments’ of Energy and Transportation in: “Building America” energy efficient homes, Photovoltaic Manufacturing, Hot-Humid PV testing of large-scale PV to show bankability, train-thetrainers education for solar installations, programs to decease the soft-costs of PV installation, Electric Vehicle Transportation (U.S. DOT’s only EV Transportation Center) and “Clean Cities” (alternative fuel transportation). Florida Utilities have funded FSEC’s SunSmart program which has placed 10 kW of PV with battery back-up at more than 100 schools to provide power to emergency shelters and education demonstrations for students. Prior to joining FSEC, Dr. Fenton spent 20 years as a Chemical Engineering Professor at the University of Connecticut. He received his PhD in Chemical Engineering from the University of Illinois in 1984 and his BS from UCLA in 1979. He is an Electrochemical Society Fellow and received the Research Award of the Electrochemical Society’s Energy Technology Division in May 2014 for his work on Automobile Proton Exchange Membrane Fuel Cells. He is the author of over 200 publications.
For additional information, please contact Prof. Xinyu Zhao at (860) 486-0241, xinyuz@engr.uconn.edu or Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu
Thermofluidic and interfacial dynamics of spark-ignited metallic droplets
Friday, October 2 • 2:30 PM – UTEB, Rm. 175
Thermofluidic and interfacial dynamics of spark-ignited metallic droplets
Dr. Sukalyan Bhattacharya
Texas Tech University
Abstract: In the first part of this talk, an intriguing experimental observation is discussed where highspeed imaging captures thermofluidic dynamics of spark-ignited nano Aluminum powder. The phenomenon consists of initial detachment, subsequent pulsation, occasional fragmentation and eventual explosion of molten metallic masses separated from the original bulk resting on a copper plate. We provide a phenomenological description elucidating every aspect of the entire process. The key consideration in constructing the explanation is recognition of the anomalous frequency value of interfacial oscillation of the metallic droplets revealing important details of their opaque interior. This leads to the second part of the talk where a novel theory shows how wave features at a drop surface can be exploited to quantify size and position of bubbles or solid particles inside the liquid domain. Such in-vivo diagnostic capability has similarity to atomic spectroscopy or application of Bragg’s law in crystallography, and can be useful in a wide range of fields including combustion technology and material processing. •
Biographical Sketch: Dr. Bhattacharya received his Ph.D. in Mechanical Engineering from Yale University in 2005. Prior to that, he obtained his Bachelor’s degree from Jadavpur University in 1997, and obtained his Master’s degree at University of Connecticut in 2000. Upon Ph. D. graduation, he joined the Department of Mechanical Engineering at Texas Tech University as an assistant professor, and became an associate professor in 2011. His research interest includes low Reynolds number hydrodynamics, turbulence, turbulent scalar transport, and statistical mechanics.
For additional information, please contact Prof. Xinyu Zhao at (860) 486-0241, xinyuz@engr.uconn.edu or Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu
Combustion: From a Jet Engine to an Exploding Star
Friday, September 25 • 2:30 PM – UTEB, Rm. 175
Combustion: From a Jet Engine to an Exploding Star
Dr. Alexei Poludnenko
Naval Research Laboratory
Abstract: Turbulent reacting flows are pervasive both in our daily lives on Earth and in the Universe. They power the modern society being at the heart of many energy generation and propulsion systems, such as gas turbines, internal combustion and jet engines. On astronomical scales, thermonuclear turbulent flames are the driver of some of the most powerful explosions in the Universe, knows as Type Ia supernovae. These are crucibles, in which most of the elements around us from oxygen to iron are synthesized, and in the last 20 years they have led to one of the most remarkable discoveries in modern science, namely of the existence of dark energy. Despite this ubiquity in Nature, turbulent reacting flows remain poorly understood still posing a number of fundamental questions. In this talk, an overview of the numerical and theoretical work at the Naval Research Laboratory over the recent years is given, aimed at studying both chemical and thermonuclear turbulent flames. Several surprising phenomena that have emerged in the course of this work will be highlighted, in particular, in the context of the intrinsic instabilities of high-speed turbulent reacting flows, as well as some of the outstanding open challenges. Finally, the implications of this work for the development of the next generation of accurate, predictive turbulent flame models required for the design of practical combustion applications will be briefly discussed.
Biographical Sketch: Dr. Poludnenko received his Ph.D. in Physics and Astronomy from the University of Rochester in 2004. Upon graduation, he joined the Department of Energy ASC Flash Center at the University of Chicago as a postdoctoral researcher, where he worked on theoretical studies of astrophysical supernovae explosions and numerical modeling of thermonuclear deflagrations and detonations. Since joining the Naval Research Laboratory in 2007 first as a National Research Council postdoctoral fellow and later as a permanent research staff member, Dr. Poludnenko has been working on a wide range of topics in combustion, numerical algorithm development for hydro- and magnetohydrodynamics, and high-performance computing. In recent years, he has been leading the research program at NRL focused on theoretical and computational studies of turbulent combustion in chemical and astrophysical systems.
Can Other Materials Besides Diamond have Ultrahigh Thermal Conductivity?
Friday, September 18 • 2:30 PM – IMS, Rm. 20
Can Other Materials Besides Diamond have Ultrahigh Thermal Conductivity?
David A. Broido
Professor of Physics Boston College, Chestnut Hill, Massachusetts
Abstract: Diamond and its carbon cousins, graphite and graphene, have long been known to have by far the highest thermal conductivities (κ) of any materials, achieving room temperature values of over 2000 Wm-1 K-1 . Other ‘high κ’ materials such as copper (κ=400 Wm-1 K-1 ) have significantly lower values. In spite of welldefined criteria to guide the search for new high κ materials, little progress has been made over the years. In this talk, I will describe a novel paradigm for achieving high κ that we have recently proposed. This paradigm introduces new criteria, which stem from fundamental vibrational properties that occur in compounds where the constituent atoms have a large mass ratio. We have calculated the lattice thermal conductivities of candidate materials using a first principles theoretical approach that combines an exact solution of the Boltzmann transport equation for phonons with accurate determination of the harmonic and anharmonic interatomic forces from density functional theory. We have demonstrated excellent agreement with the measured thermal conductivities of a wide range of materials, validating the predictive capability of this theory and contributing insight into the nature of thermal transport in materials. Guided by the new paradigm, we have identified one material, cubic boron arsenide, that should have an exceptionally high room temperature κ comparable to the highest known bulk value achieved in diamond. This finding opens opportunities for controlling phonon thermal transport, which may facilitate the design of new high κ materials for thermal management applications.
Biographical Sketch: David Broido is currently a Professor of Physics at Boston College. He received his Ph.D. degree in Theoretical Physics from the University of California at San Diego in 1985. He was a National Research Council Postdoctoral Fellow at the U.S. Naval Research Laboratory before coming to Boston College in 1987. He is a Fellow of the American Physical Society. His research interests include theoretical studies of thermal and thermoelectric transport properties of materials using first principles approaches. https://www.bc.edu/schools/cas/physics/people/david_broido