SUNMONTUEWEDTHUFRISAT
Conferences, Lectures, & Seminars
Events for March
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Inside Polymer Nanocomposites - Interphases and Percolation
Wed, Mar 05, 2008 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
L. Cate BrinsonMechanical Engineering and Materials Science and
EngineeringNorthwestern UniversityAbstract:Polymeric nanocomposites made by incorporating small amount of nanoscale inclusions into polymer matrices exhibit dramatic changes in thermomechanical properties over the pure polymers. The properties of the nanoscale fillers can be extraordinary, yet the significant changes observed cannot be due to the nanofillers alone. Enhancing their effect is the extremely significant role that the interphase plays in these systems. Given the enormous surface to volume ratio for nanoparticles, the interphase volume fraction can dwarf that of the inclusions themselves and percolate through the composite. In this talk, experimental evidence of the existence of this interphase region is presented for several nanofiller types via local and global glass transition changes and microscopy. We show that by properly controlled functionalization of the nanoscale inclusions, we can impact the properties of the interphase region and consequently control the properties of the nanocomposites. In conjunction with the experimental results, the viscoelastic behavior of multi-phase polymeric nanocomposites is modeled using a novel hybrid numerical-analytical approach that can effectively take into account the existence of the interphase region and be used to elucidate experimental results and aid in materials design. To investigate the concept of percolated interphase, a finite element approach is developed to study the impact of interphase zones on the overall properties of composite. The results have impact on potential commercial applications for nanocomposites including transparent conducting films, wear resistant coatings and hybrid systems for multifunctional performance including sensing and damage toleranceLocation: Seaver Science Library, Rm 150
Audiences: Everyone Is Invited
Contact: April Mundy
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Development of Upconversion Nanophosphors for Bioimaging and
Wed, Mar 12, 2008 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Yiguang JuDepartment of Mechanical and Aerospace
Princeton UniversityPrinceton, USAAbstractUpconversion nanophosphors provide new opportunities for bioapplications because of their stable optical property, increased light penetration depth in tissue, low toxicity, and reduced background scattering compared to conventional markers. First, the seminar will give a review of the recent progress of synthesis of rare-earth (erbium and ytterbium) doped upconversion nanophosphors by using combustion and in-solution thermolysis methods. Second, the particle morphology and the luminescence properties with infrared excitation are investigated. The correlations between the nanoparticle fluorescence, particle crystal structure, synthesis temperature, and precursor conditions are summarized. The dynamic dependence of particle luminescence time on particle size and phonon energy will be analyzed. The kinetic mechanism of the non-linear dependence of the luminescence intensity on the excitation power is discussed. Third, the ability of specific targeting of functionalized upconversion nanophosphors on surfaces coated by biotins will be demonstrated. Finally, the efficacy of photodynamic therapy by using upconversion nanophosphors on singlet oxygen production and lung cancer tissue growth are presented.
Location: Seaver Science Library, Rm 150
Audiences: Everyone Is Invited
Contact: April Mundy
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Micro and Miniature Technologies of Advanced Energy and Thermal Systems
Fri, Mar 14, 2008 @ 12:00 PM - 01:00 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Amir FaghriUnited Technologies Endowed Chair Professor in
Thermal-Fluids EngineeringUniversity of ConnecticutAbstract:The 21st century will see the development of a wide range of active miniaturized energy devices with application in energy management and power sources, electronic cooling, energy storage and bioengineering. Although these active devices are effective, they are often cumbersome and inefficient considering the auxiliary supporting devices such as pumps, fans, and other moving parts they require for operation. A more efficient and novel approach involves use of passive small energy and thermal devices with no moving parts. Two research thrusts will be presented in this talk. We propose a new miniature passive direct methanol fuel cell (DMFC) that includes a fuel cell stack and ancillary systems with no moving parts. This system uses passive approaches for fuel storage and delivery, air breathing, water management, CO2 release, and thermal management. The performance characteristics of the passive miniature DMFC system will be presented.Increasing component densities of the integrated circuit (IC) and packaging level have led to serious challenges in thermal management problems in electric cooling. Micro heat pipes are one of the promising cooling devices because of their high efficiency, reliability and cost effectiveness. Theoretical and experimental analysis performed on micro and miniature heat pipe arrays reveals a 300% improvement in effective thermal conductivity at high heat fluxes over conventional approaches.BiographyDr. Faghri is currently the United Technologies Endowed Chair Professor in Thermal-Fluids Engineering. He was the Dean of the School of Engineering from 1998-2006, and the Head of the Mechanical Engineering Department from 1994-1998 at the University of Connecticut. Dr. Faghri developed major initiatives and incentives to promote quality research and graduate education, including establishing the Connecticut Global Fuel Cell Center with significant support from the federal and state governments, as well as the private sector. Dr. Faghri has authored seven books and edited volumes, more than 260 archival technical publications (including 160 journal papers), and 11 U.S. patents. His latest textbook, Transport Phenomena in Multiphase Systems, was published by Elsevier in 2006. He has served as a consultant to several major research centers and corporations, including Los Alamos and Oak Ridge national laboratories, ExxonMobil, and Intel Corporation as well as serving on the boards of directors of both publicly-traded and private companies. Dr. Faghri has served as a principal investigator conducting research in the area of thermal management and multiphase transport phenomena for applications ranging from advanced cooling systems to alternative energy systems including fuel cells, solar energy systems and thermal energy storage devices. Dr. Faghri has received numerous external research contracts and grants from the National Science Foundation, National Aeronautics & Space Administration, Department of Defense, Department of Energy, and various industries. Dr. Faghri has received many honors and awards, including the 1998 American Institute of Aeronautics & Astronautics (AIAA) Thermophysics Award, the 1998 American Society of Mechanical Engineering (ASME) Heat Transfer Memorial Award and the 2005 ASME James Harry Potter Gold Medal.Dr. Faghri received his M.S. and Ph.D. degrees from the University of California at Berkeley, and a B.S. with highest honors from Oregon State University.Friday, Mar. 14, 2008KAP14412:00 pm
Lunch will be servedPlease RSVP to: amundy@usc.eduLocation: Kaprielian Hall (KAP) - 144
Audiences: Everyone Is Invited
Contact: April Mundy