MECHANICAL ENGINEERING DEPARTMENT SEMINARS
Spring Seminar Series 2005
Fridays 2:30-3:30 PM, Room: 3-370
| February
4 |
|
Towards high-speed ocean vessels: the experimental investigations
of fish-like swimming hydrodynamics
Abstract: Future design and operation of high-speed surface and underwater vessels depends on accurate modeling of complex unsteady hydrodynamic phenomena at high Reynolds numbers. The challenges of identifying the underlying physics for these hydrodynamic processes are equally impressive for both numerical and experimental approaches to such unsteady three dimensional problems. Recent underwater vehicle designs mimic fish swimming to achieve high maneuverability and effective propulsion. Ongoing experiments aim to determine kinematics parameters for enhanced vehicle performance, often drawing inspiration from live fish: flapping foils yield high thrust and offer enhanced maneuvering capabilities; undulating body motions tend to decrease local near-body turbulence levels; and live fish reveal complex three-dimensional ring-like vertical structures in their wake. Hydrodynamic characteristics will be discussed for problems ranging from flapping foil propulsors, undulating hull-forms, and live fish swimming to the energy extraction from unsteady flows by flexible membranes.
|
Short-bio: Prof. Alexandra Techet is currently an Assistant Professor of Mechanical and Ocean Engineering at MIT. She received her B.S.E. in Mechanical and Aerospace Engineering in 1995 from Princeton University and then graduated from the MIT/WHOI Joint Program in Oceanographic Engineering with a M.S. in 1998 and a Ph.D. in 2001. Prof. Techet specializes in experimental unsteady marine hydrodynamics at high Reynolds numbers, and her research interests include fish swimming hydrodynamics, flow-structure interactions in offshore systems, and complex free-surface hydrodynamics, including ship hydrodynamics and the impact of objects on a water surface.
|
| February
11 |
|
Tissue Engineering-From the Bench to the Bedside & Back
Abstract: The most well recognized applications of tissue engineering involve new therapies for an array of clinical problems; from diabetes and liver failure to bone can cartilage repair. The goal is to create new tissue either directly in the patient via cell transplantation or directed growth from nearby healthy tissue, or by growing tissue outside the body for transplantation into the patient. In the future, engineered tissues ‘on a chip’ could greatly accelerate the development of new drugs that may cure patients, eliminating the need for organ transplants altogether. This talk will highlight the integration of molecular and macroscopic design principles in tissue engineering, with an emphasis on the new frontiers including bench-scale physiological models of human tissue using liver as a paradigm.
|
Short-bio:
LINDA GRIFFITH is a Professor of Mechanical and Biological Engineering at MIT and is Director of the NSF-funded Biotechnology Process Engineering Center, an engineering research center that focuses on gene therapy and stem cells. She received a Bachelor's Degree from Georgia Tech in 1982 and a PhD degree from the University of California at Berkeley in 1988, both in chemical engineering. Following a postdoc with Robert Langer and Joseph Vacanti at MIT and Children's Hospital, she joined the faculty at MIT in Jan. 1991, teaching at MIT and Harvard Medical School. Dr. Griffith is a co-founder of Therics, Inc. and has served as consultant or scientific advisory board member for Advanced Tissue Sciences, AstraZeneca, Biohybrid Technologies, Corning, Cytotherapeuctics (Stem Cells, Inc.), DuPont, Schroeder Ventures, Therics, The Whitaker Foundation, Harvard School of Dental Medicine, and the Illinois Institute of Technology Pritzker Institute of Medical Engineering. Her work has been featured on several television documentary shows including Scientific American Frontiers hosted by Alan Alda. Her awards include the Popular Science Brilliant 10 award, NSF Presidential Young Investigator Award, MIT Class of ’60 Teaching Innovation Award, along with named lectures at academic institutions and societies. She is a Fellow in the Cambridge-MIT Institute. She has served as Co-Chair of the Materials Research Society Annual Spring Meeting, the Keystone Tissue Engineering Meeting, and the joint NSF-NIH Workshop on Bioengineering and Bioinformatics Training and Education, and is a member of the Advisory Council for the National Institute for Dental and Craniofacial Research at NIH. At MIT she chairs the Undergraduate Programs Committee for Biological Engineering, and led development of MIT’s new SB in Biological Engineering, which was approved in 2005 as MIT’s first new undergraduate “course of study” in 29 years.
|
| February
18 |
|
Small-scale gaseous hydrodynamics and the breakdown of
the Navier-Stokes description
Abstract:
The recent interest in systems and devices operating at small scales (MEMS, NEMS) has resulted in a need to expand our ability to model gaseous hydrodynamics at small scales. Of particular interest to us is a number of theoretical challenges which arise from the breakdown of the Navier-Stokes description when the characteristic flow length-scales approach the fluid internal scale (in this case the molecular mean free path). In this talk we will discuss recent progress in the theoretical modeling and simulation methods for small-scales gaseous flows in regimes where the Navier-Stokes description is expected to fail. On the simulation front we will present a recently developed simulation method for solving the Boltzmann equation which governs gaseous hydrodynamics beyond the Navier-Stokes description; the method presented here is significantly more computationally efficient compared to existing methods. On the flow-physics front we will discuss solutions to basic flow problems which extend our understanding of transport in gaseous systems beyond the Navier-Stokes limit. Both fluid flow and convective that transfer will be considered. Finally we will present a recently developed second-order
slip model that extends the applicability of the Navier-Stokes description to length-scales approaching the mean free path scale. Such models are very desirable since analytical and numerical solutions of the Navier-Stokes description are significantly easier to obtain than solutions of the more general Boltzmann equation. |
Short-bio: Professor Nicolas Hadjiconstaninou is an Associate Professor in the department of Mechanical Engineering at MIT. He received his B.A. in Engineering from Cambridge University in 1993, and his Ph.D. in Mechanical Engineering from MIT in 1998. After spending a year at Lawrence Livermore National Laboratory as a Lawrence Fellow, he joined the faculty at MIT. His interests include molecular modeling and simulation of complex hydrodynamics, and characterization and extension of the limits of continuum theories. |
| February 25 |
|
Experts Methods for Control
Abstract:
We consider control problems where a decision-maker must choose actions sequentially, to maximize cumulative rewards that are functions of his actions and of "states" of an underlying system. "Experts algorithms'' constitute a methodology for dealing with this situation, when an accurate model for how the system's state evolves is not available. An experts algorithm has access to a set of strategies ("experts''), each of which recommends an action. Traditional experts algorithms are motivated by prediction problems and learn how to combine recommendations of individual experts so that, in the long run, for any fixed sequence of states of the system, it does as well as the best expert would have done relative to the same sequence. This methodology may not be suitable for control problems, where the evolution of states of the system depends on past chosen actions. We present a general exploration-exploitation experts method that is suitable for control problems. The method is shown to asymptotically perform as well as the best available expert. Several variants are analyzed from the viewpoint of the exploration-exploitation tradeoff, and complexity and performance bounds are proven. This is joint work with Nimrod Megiddo.
|
Short-bio: Daniela Pucci de Farias received the B.S. in Computer Engineering and the M.S. in Electrical Engineering in 1997 and 1998, both from the State University of Campinas, Brazil, and the Ph.D. in Management Science and Engineering in 2002, from Stanford University. She joined the department of Mechanical Engineering at MIT in 2003, after spending a year as a postdoctoral associate at IBM Almaden. Her research interests lie in decision-making in large-scale systems, with current focus on approximate dynamic programming and games. Daniela is the recipient of an IBM Research Fellowship, the 2002 INFORMS Dantzig Dissertation Award and a 2004 IBM Faculty Award, and current holds an Edgerton Faculty Career Development chair.
|
| March 4 |
|
The Structural Design of Electrode Materials for High-Energy- and
High-Power Lithium Batteries
Abstract: Since their introduction to the market in 1990, rechargeable lithium batteries have made a phenomenal impact in powering consumer electronic devices such as cell phones and laptop computers. The market size for these batteries is now $4-5 billion. The need for new electrode materials that will provide additional energy, power and a superior cycle life to satisfy the increasing demands for reliable, high-energy/high-power batteries by the transportation, medical, space, and defense sectors will ensure that lithium battery research will continue for many more years to come. This presentation will highlight the critical role that structure plays in the design of battery electrodes and the recent advances that have been made in developing two-component, structurally-integrated electrode systems to achieve performance objectives. The presentation will be made in the context of the advantages and limitations of other battery systems.
|
Short-bio: Michael Thackeray is a group leader and senior scientist in the Battery Department of the Chemical Engineering Division at Argonne National Laboratory. He received his Ph.D. from the University of Cape Town, South Africa and studied as a post-doctoral student at Oxford University, UK. He was manager of the Battery Unit at the Council of Scientific and Industrial Research, South Africa before taking up his current position at Argonne in 1994.
|
| March
11 |
|
Power Mems and Mechanical Engineering:
Old Problems Made New
Abstract: Po wer micro electrical and mechanical systems (Powers MEMS) is an emerging field which focuses on the application of micro systems technology to heat engines. With length scalesof microns to millimeters, these small machines have applications such as propulsion, power production and cooling. The potential utility of such an approach can be appreciated by noting that modern large scale mechanical engineering triumphs such as a large gas turbine engines can produce 100s of MW, enough to power a city. Thus, an engine with a millionth the airflow capacity (about the size of a shirt button) could produce 10-100W (a power level of great interest for powering portable electronics), all else being the same. Of course, all else is not the same when scaling machines down by a factor of a million (in linear scale). While the thermodynamics do not change at micro scale, mechanics do. Fluid, structural, and electro mechanics can be considerably different at micro scales leading to much different design approaches. This talk discusses engineering challenges and research opportunities in power MEMS. System level design is discussed and engineering issues are reviewed in the disciplines of fluids, heat transfer, structures, materials, rotor- dynamic, and electro mechanics. Much of the focus will be on lessons learned in the MEMS gas turbine generator, pump and rocket engine projects ongoing at MIT. These projects teach that the heat engine design problems do not change at micro scale, but that the comfortable engineering solutions of old new longer suffice. Emphasis is on the contrast between conventional and micro approaches to design an disciplinary challenges.
|
Short-bio: Dr. Alan H. Epstein is the R.C. Maclaurin Professor of Aeronautics and Astronautics. He received all of his degrees in Aeronautics and Astronautics from MIT and has been on the faculty there since 1980. In addition to serving as Director of the MIT Gas Turbine Laboratory, Dr. Epstein leads the MIT MicroEngine Project, an interdisciplinary team developing shirt button sized gas turbine generators, rocket engines, and chemical lasers based on microsystem technology. He has over 100 technical publications in the fields of energy conversion, aero and rocket propulsion, instrumentation, and microsystems. Dr. Epstein is a member of the National Research Council Board on Army Science and Technology and a member of the DRAPA Defense Science Research Council. He has received 4 ASME best paper awards, the ASME Gas Turbine Award, and the International Gas Turbine Institute Scholar Award. Professor Epstein is a fellow of the AIAA and a member of the National Academy of Engineering.
|
| March 18 |
|
The Elusive Cure for Alzheimer's Disease: A Bioengineering Perspective
Abstract: Alzheimer’s Disease currently afflicts 50% of all individuals over the age of 85, so as our population grows, so too, will the personal suffering and cost to our society due to this affliction. While no cure has yet been found, several promising approaches are currently the focus of intense research. One theory proposes that the early aggregates, oligomers or protofibrils, of amyloid-beta protein are toxic to neurons because they fuse with the cell membrane, increasing its permeability and ultimately causing cell death. Treatments consequently focus on ways to break down or otherwise "neutralize" these neurotoxic species. This seminar will show how a bioengineering approach that combines molecular dynamic simulation and experiment might contribute to our understanding of Alzheimer's Disease and potential strategies for a cure . |
Short-Bio: The Kamm Lab works on a variety of projects from the fundamental mechanisms by which cells sense and respond to mechanical stimulus, to the role of scaffold biophysical properties in initiating an aniogenic response, to the molecular mechanisms of Alzheimer's sidease. Kamm received his PhD from MIT in 1977, and is currently a member of the MIT Mechanical Engineering and Biological Engineering faculties. He is a Fellow of the American Society of Mechanical Engineers and the American Institute of Medical and Biological Engineers. He is recognized for his contributions to biomedical fluid mechanics, respiratory mechanics, and most recently, the mechanics of single cells. |
| April 1 |
|
Photovoltaics and the Epoch of Renewable Energy
Abstract: Our technology-rich civilization is founded on the assumption of a continuous and abundant supply of energy. Yet, over the next few decades, this assumption will be challenged and our response will define a new epoch. At the present time, we are in the epoch defined by Fossil Fuel, which began in the late 1800's when coal overtook wood as the primary energy source. Oil became our primary source of energy in the 1950's and remains so today with large contributions from nuclear and hydro. Yet, we know that the Fossil Fuel Epoch will draw to a close within decades due to a combination of issues including fundamental availability, political instability of supplier nations and concerns about global climate change. Developing sustainable primary energy sources is one of the grand challenges that civilization faces today. Photovoltaics (PV), the direct conversion of sunlight to electricity using semiconductor devices, has the potential to be a foundation stone for an epoch based on renewable sources. This talk will begin by scaling the energy requirements and the solar resource. The status of the PV industry will be presented with a summary of the development of technology as well as progress in cost/performance. The author's own work on String Ribbon will be described. String Ribbon is a manufacturing process for the direct production of tin crystalline silicon substrates in a continuous ribbon directly from a melt ( www.evergreensolar.com). By eliminating the need to slice wafers |
Short-Bio: |
| April 8 |
|
Assembly of Nanotubes: a Mechanical Way
Abstract: A method for nanoassembly has been developed. Current efforts of guided growth or self-assembly of carbon nanotubes (CNTs) cannot integrate nanostructures to micro/macro structures in a long range order. Direct mechanical assembly of CNTs have been envisioned by many researchers, but not reported yet. Nanopelleting is to make CNTs assemblable firstly, and then have them assembled. This new concept allows mechanical assembly of nanostructures by embedding nanostructures in micro-scale blocks that can be transplanted, oriented and bonded readily. This technique includes vertical growth of carbon nanotubes, pellet casting, planarization, pellet separation, transplantation and bonding. A specific manufacturing process is developed and tested with favorable results. This talk will highlight the transplantation of CNT's with an emphasis on the new functionalities of nanoprobes enabled by this manufacturing technique. |
Short-Bio: Professor Sang-Gook Kim is an Associate Professor of Mechanical Engineering at MIT. He received a B.S. at Seoul National University in 1978, a M.S. at KAIST in 1980 and a Ph.D. at MIT in 1985, all in mechanical engineering. From 1985 to 1986, he was a manufacturing manager manager at Axiomatics Corp., Cambridge, MA. He then joined the Korea Institute of Science and Technology in 1986 as a senior research staff until 1991. He moved to Daewoo Corporation, Seoul, Korea in 1991, as a general manager at the Corporate Chairman's Office. He directed the Central Research Laboratory at Daewoo Electronics since 1994, and was promoted to a corporate director and corporate executive director in 1995 and 1998, respectively. Professor Kim returned to MIT in September 2000 as a faculty of Mechanical Engineering. His current research interests are: PZT MEMS for optical/RF products, energy harvesting for portable energy, carbon nanotubes assembly, and nano-manufacturing in multi-scale systems. |
| April
15 |
|
Thermal Transport Mechanism in Interfacial and Defected Crystalline Materials
Abstract: Established tools for the manufacture of systems with micro-scale features include standard lithography techniques. This talk examines a different method for microscale manufacture called Microscale Robotic Deposition (MRD). This is a solid freeform fabrication technique where by material is deposited to rapidly 'build up' complex 3 dimensional structures. We will introduce a system that focus on the creation of periodic, lattice-like structures with several potential applications. This is a truly interdisciplinary research effort involving Materials Science, Manufacturing, and Controls. Each of these aspects will be highlighted briefly before focusing on the main topic of discussion. The main topic of this talk centers on the control aspects of the MRD problem, particularly the precision motion control problem. The periodic nature of the systems under construction allow for the use of an Iterative Learning Control (ILC) approach to Friday, April 8 (2:30 - 3:30 PM) - Room, 3-370 Professor positioning problem. Iterative Learning Control utilizes information from a previous attempt at a task to update a feed forward signal and better the tracking performance on future attempts at the identical task. Most practical ILC designs incorporate some stabilizing filtering mechanisms to provide robustness to the learning process. In this talk we will extend that approach by introducing time varying and adaptive filtering techniques. The adaptation is based on Time-Frequency analysis. By identifying where high frequency system dynamics are evident, we are able to adjust a stabilizing filtering mechanism so as to circumvent the standard tradeoff between performance and robustness. In addition to presenting the algorithms, this talk will briefly discuss stability guarantees associated with the method. The talk will present several experimental results that validate the analysis.
|
Short-bio: Professor Alleyne received his B.S. in Engineering Degree from Princeton University in 1989 in Mechanical and Aerospace Engineering. He received his M.S. and Ph.D. degrees in Mechanical Engineering in 1992 and 1994, respectively, from The University of California at Berkeley. He joined the Department of Mechanical and Industrial Engineering at the University of Illinois, Urbana-Champaign in 1994 and is also appointed in the Coordinated Science Laboratory of UIUC. He currently holds the Ralph M. and Catherine V. Fisher Professorship in the College of Engineering, was awarded the ASME Dynamics Systems and Control Division’s Outstanding Young Investigator Award in 2003, and was a Fulbright Fellow to the Netherlands where he held a Visiting Professorship in Vehicle Mechatronics at TU Delft. His research interests are a mix of theory and implementation with a broad application focus. He has been active in the ASME, the IEEE, and several other societies where he has contributed extensively as an editor, associate editor, author, reviewer, and organizer. Further information about the toys he and his students play with can be found at the following website: http://mr-roboto.me.uiuc.edu.
|
| April 22 |
|
Thin Film Solid Oxide Fuel Cells
Abstract: After a brief summary of selected research projects in the Mechanical Engineering Department at Stanford, I will discuss experiments exploring the feasibility of low temperature solid oxide fuel cells. One bottleneck is the ease of ion conduction in electrode and electrolyte membranes. Another is the rate of catalytic reactions at anode and cathode. Our research focuses on understanding and reducing the barriers for ionic flux and developing fabrication strategies for building membrane layers with a thickness of only a few hundred atomic layers. Finally, I will draw analogies to 'nature made fuel cells' such as mitochondria and chloroplasts.
|
Short-bio: Prof. Friedrich B. Prinz is Chair, Department of Mechanical Engineering, Stanford University. Since 1994, he has been the Rodney H. Adams Professor of Engineering, Stanford University, with dual appointments as Professor of the Departments of Mechanical Engineering and Materials Science and Engineering. From 1994 to 2003, he was Co-Director of the Alliance for Innovative Manufacturing (AIM) at Stanford. Before joining Stanford University in 1994, he had been on the faculty of Carnegie Mellon University for nearly 14 years and was Professor of Mechanical Engineering from 1987 to 1994, as well as Director of the Engineering Design Research Center (NSF-ERC) from 1989 to 1994. He has published over 100 papers, among which the recent ones focus on ionic conductivity at nanoscale, and on the performance of novel fuel cell structures. Prof. Prinz was invited to deliver the Sir Christopher Hinton Lecture, Royal Academy of Engineering, UK, in 1991, and awarded Engineer-of-the-Year (1991-1992), American Society of Mechanical Engineers, Pittsburgh, PA Section. In 1996, he was elected Austrian Academy of Science (foreign member), Vienna, Austria. He holds a PhD degree (1975) in Physics from the University of Vienna, and has been active in synergistic activities with organizations like the National Research Council Committees, the Japanese Technology Evaluation Center and World Technology Evaluation Center, as well as Portuguese Science and Technology Foundation.
|
| April 29 |
|
Experimental investigations of 2D separation
Abstract:
Unsteady separation is an unsolved, yet technologically important, problem. The goal of this research is to provide the first experimental verification of a new, rigorous, analytical criteria for identifying the location and geometry of unsteady separation based on measurable surface quantities, such as skin-friction and pressure. This makes the criteria practical for real-world implementation, where surface information is the only quantitative data realistically attainable.The experimental arrangement is a so-called rotor-oscillator flow, comprising a cylinder rotated about its long axis in a box filled with viscous fluid. Rotation of the cylinder induces separation from the sidewall boundary, which is uniform along the length of the cylinder and therefore nominally two-dimensional. The flow separation is made unsteady by left-and-right translational motion of the cylinder. Shear-stress data is obtained using thermal sensors and the location of separation determined from analytic criteria. The predictions based on surface data are then compared with dye visualizations of the separating flows.
|
Short-bio: Thomas Peacock received B.Sc. from Manchester University (1994) and D. Phil. from Oxford University in 1998. In 2000 he joined Massachusetts Institute of Technology and currently he is an Assistant Professor at Mechanical Engineering department (at MIT). His current research interests include Nonlinear Dynamics, Fluid Dynamics, Experimental Methods and Applied Mathematics. |
| May 6 |
|
Design and Control of a Liquid-Fueled
Actuator for Self-Powered Robots
Abstract:
The most common power supply and actuation system for self-powered human-scale robots is an electrochemical battery and DC motor combination. The energy and power density provided by this type of system, however, falls far short of that which would be required to provide an acceptable level of energetic autonomy. Operation times on the order of 15 to 25 minutes are common in self-powered position or force controlled human-scale robots. As such, the energetic limitations of state-of-the-art power supply and actuation systems represent a major technological roadblock for designing human-scale actuated mobile robots that can operate power-autonomously for a useful period of time. This presentation describes the design of a power supply and actuation system that offers a high energy-density alternative to standard battery-powered DC motor actuated position or force controlled human-scale robots. The proposed approach utilizes a liquid monopropellant, which is decomposed on-demand and injected directly into a pneumatic cylinder. The presentation describes the evolution of the design approach, trade-offs between efficiency and complexity, the development of force controllers, and efforts toward the energetic characterization of the system.
|
Short-bio: Michael Goldfarb received the B.S. degree in mechanical engineering from the University of Arizona in 1988, and the S.M. and Ph.D. degrees in mechanical engineering from the Massachusetts Institute of Technology in 1992 and 1994, respectively. In 1994 he joined the Department of Mechanical Engineering at Vanderbilt University, where he is currently an Associate Professor. His current research interests include the design of high-energy-density robotic actuators, the control of fluid-powered actuators, and the design and control of haptic interfaces and telemanipulator systems. |
[ If you have any questions with regard to the seminar series, please contact Professor Yang Shao-Horn at 617-253-2259 or shaohorn@MIT.EDU ]