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Conferences, Lectures, & Seminars
Events for September
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NANOTECHNOLOGY AND THE DEVELOPMENT AND ANALYSIS OF ENERGETIC MATERIALS
Fri, Sep 09, 2005 @ 02:30 PM - 04:00 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Presented by:Professor Richard A. YetterMechanical Engineering, Pennsylvania State UniversityAbstract:Over the next decade, nanotechnology is expected to produce significant advancements in the development of energetic materials. Much of the highly desirable traits of nano-sized ingredients (e.g., metal powders and crystalline oxidizers) in energetic materials have been attributed to their high specific surface area (high reactivity), lower melting temperatures, increased catalytic activity, and potential ability to store energy in surface defects. In addition, the nano dimensions of these materials result in small characteristic transport times for mass and energy between fuel and oxidizer.
Metal additives have long been used in energetic materials to increase energy densities. Although the addition of micron-sized metal particulate has been successful in many applications, their size generally limits overall combustion times, requires high ignition temperatures, and generates condensed phase products also of micron size. The possibility of increasing the reactivity of metal particulate, thereby lowering ignition temperatures and shortening reaction times, as well as increasing densities and overall energy, could greatly enhance existing uses and even generate new usage of metals in reactive systems. In the presentation, the oxidation and combustion characteristics of metal nanoparticles are reviewed and compared with micron-sized particles. In addition, their application in various fuels, propellants, and explosive systems are summarized.
While usage of nano-ingredients in current energetic materials has demonstrated considerable benefits that can be attributed to the characteristics of the nano-material, much of the anticipated benefits have not been realized due to the use of conventional fabrication techniques in integrating the nano-material into the formulations. The presentation also examines new ways to assemble nano-energetic materials, including self-assembly of components with sizes in the nm to mm range, to provide concurrent increases in performance and managed energy release while providing reduced sensitivity and ease of processing and handling. Refreshments will be served at 2:30p.m.Location: Vivian Hall of Engineering (VHE) - 217
Audiences: Everyone Is Invited
Contact: Petra Pearce
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Lyman Handy Colloquium
Thu, Sep 15, 2005
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Programmable molecular sensors and switches: applications in metabolic engineering, intelligent therapeutics, and bbiosensorsPresented By:Professor Christina D. SmolkeDivision of Chemistry and Chemical Engineering, California Institute of TechnologyABSTRACTCells employ a variety of different sensor biomolecules to dynamically evaluate their environments and trigger appropriate metabolic responses. The ability to program cells with engineered molecules that can sense structural and chemical events is a critical technology for many of the challenges that face us in biotechnology and medical research. Recent progress in the design of tailor-made molecular switches and sensors is rapidly advancing our ability to engineer smart systems that will perform information processing or signal integration within cells or complex biological samples. I will discuss our work in the design a new class of nucleic acid-based molecular sensors that transform different types of informational input into biological function and their application in regulating complex cellular behavior. In particular, the application of these devices to metabolic engineering strategies for microbial alkaloid synthesis, targeted molecular therapies, and diagnostic devices will be addressed. **All first year materials science graduate students are required to attend**
Location: Olin Hall of Engineering (OHE) - 122
Audiences: Everyone Is Invited
Contact: Petra Pearce
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Materials Science Program Seminar
Fri, Sep 30, 2005
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
THE MORK FAMILY DEPARTMENT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE PRESENTS A SEMINAR
BYProfessor Adri van Duin Materials and Process Simulation Center, Beckman Institute
Caltech, Pasadena, CAA transferable computational method for atomistic-scale dynamical simulations of chemical reactionsAbstractCoupling the structures, compositions, and properties at the atomistic level to predictions of macroscopic properties and processes provides an enormous technical challenge for computational chemistry, physics, materials science, and engineering. This lecture will provide an overview of the applications and background of the ReaxFF reactive force field, which provides a method for incorporating chemical reactions in atomistic simulations. ReaxFF is a bond-order dependent force field method that includes a geometry-dependent polarizable charge distribution, allowing reactive, atomistic scale dynamic simulations at a computational expense magnitudes lower than quantum mechanical (QM) simulations. While initially developed for first-row elements, over the last years we found the method to be highly transferable, allowing us to develop ReaxFF descriptions for covalent, metallic, ionic and mixed systems all across the periodic system.Ongoing projects involving ReaxFF include:- Reactions on Ni/Pt/Ru anodes and cathodes in fuel cells
- Hydrogen and oxygen transfer through fuel cell electrolytes
- Carbon deposition and nanotube growth catalyzed by transition metals
- Hydrogen storage in magnesium and magnesium fluorides
- Stress-induced cracking in silicon and aluminium oxides
- Temperature and chemistry-induced failure of silicon polymers
- Nitramine and peroxide-based high-energy material sensitivity
- Energy release of nitramine/metal/metal oxide composite materials
- Enzyme catalysis
- Iron melting at the temperatures and pressures of the Earth's core
- Dielectric breakdown in silicon-based semiconductors
-This lecture will address the highlights from this research and will discuss the concepts behind ReaxFF and its relation to other computational simulation methods, including its implementation in a multiscale simulation environment (CMDF) that allows coupling of different length- and time scales.
Location: Vivian Hall of Engineering (VHE) - 217
Audiences: Everyone Is Invited
Contact: Petra Pearce