Conferences, Lectures, & Seminars
Events for September
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AME Department
Wed, Sep 07, 2011 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Dr. Katerina Aifantis, European Research Council Grantee, Deptartment of Mechanics; Aristotle University of Thessaloniki, Greece; and Adjunct Assistant Professor Department of Physics Michigan Technological University, Houghton, Michigan
Talk Title: Nanostructured Anodes for Next Generation Li-Ion Batteries - -
Abstract: The current and future applications of secondary Li-ion batteries range from powering cell phones and electric vehicles to biomedical devices. Extensive work is, therefore, being performed on further improving their lifetime and cyclability. Experimental research has yielded that Sn and Si can provide three-to-ten times the capacity of commercially used graphitic anodes. What inhibits the commercialization of such anodes, however, is the 300% volume expansion, and subsequent fracture, that Sn and Si experience upon maximum Li-insertion. This fracture is minimized by embedding nanosized Sn and Si in a matrix. In the present talk it will be shown how electrochemical cycling, transmission electron microscopy, and continuum mechanics can be employed to develop design criteria that predict the most optimum matrix material, as well the Sn particle size and inter-particle spacing, that will significantly limit fracture. Nanostructured Sn-based anodes will be shown that have a 100% capacity retention for 400 cycles.
Host: Andrea Hodge
Location: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: April Mundy
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AME Department
Wed, Sep 21, 2011 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Yen Lin Han, Assistant Professor in Residence, University of Connecticut
Talk Title: Applications of Molecular Gas Dynamics to MEMS Devices
Abstract: Assistant Professor-in-Residence
Department of Mechanical Engineering
University of Connecticut
ABSTRACT:
Continuing advances in MEMS fabrication capabilities have facilitated significant progress in miniature devices. This can be achieved by utilizing molecular gas dynamics phenomena such as mass separation, thermal edge, and thermal creep flows. Besides the better-known Knudsen Compressor, other examples, including a continuous trace gas preconcentrator, and a thermal bimorph micropump will be discussed.
A trace gas preconcentrator is commonly included in gas detection systems to increase the ultra low, yet dangerous trace gas concentration, to the level at which a detection unit can accurately determine the presence of the trace gas. The widely-used adsorption/desorption preconcentrators interrupt gas flows for significant periods, in order to accumulate sufficient number of trace gas molecules, before they are released to the detection unit. The continuous Trace Gas Preconcentrator provides a unique approach, utilizing molecular gas dynamics theory to provide mass separation. In the continuous trace gas preconcentrator, the gas flow is not stopped and the time required to reach the proper concentration is significantly shorter than the adsorption/desorption method.
Using the rarefied gas dynamic phenomenon of thermal edge flow, a micropump with a built-in thermal bimorph microvalve is studied. This micropump contains an isolated heating element, made of thermal bimorph materials, that is serve as a heating element to initiate the flows, and to thermally activated bimorph valve. DSMC (Direct Simulation Monte Carlo) simulation results indicate the flow characteristics, including the maximum pressure ratio and mas flow rate vary with the bimorph valve lengths and the flow channel sizes. Finite element analysis of selected thermal bimorph structures has also demonstrated proper deflections of the thermal bimorph valve. Combining the flow and structural studies, the characteristics of the thermal bimorph micropump can be realized for future fabrication and experimental investigations.
Host: Professor Phil Muntz
More Info: http://ae-www.usc.edu/seminars/9-21-11-han.shtmlLocation: Seaver Science Library (SSL) - Room 150
Audiences: Everyone Is Invited
Contact: April Mundy
Event Link: http://ae-www.usc.edu/seminars/9-21-11-han.shtml
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AME Department Seminar
Wed, Sep 28, 2011 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Denis Phares, Professor, Department of Aerospace & Mechanical Engineering, University of Southern California
Host: Dr. Geoff Spedding
More Info: http://ame-www.usc.edu/seminars/index.shtml#upcomingLocation: John Stauffer Science Lecture Hall (SLH) - 100
Audiences: Everyone Is Invited
Contact: April Mundy
Event Link: http://ame-www.usc.edu/seminars/index.shtml#upcoming