June 2013 - Msepostdoc-list

FW: Seminar Notice: Y. Wang PhD Prelim Pt I, 6/27/13 8:45 am, ARMS 3109
by Stacey, Lisa A 20 Jun '13

20 Jun '13

MATERIALS SCIENCE AND ENGINEERING SEMINAR Minimal Tortuosity Rechargeable Batteries: a Critical Analysis By: Yunbo Wang Ph.D. Prelim Exam - Part I Advisor: Prof. R. E. Garcia ABSTRACT In this prelim 1, existing and emerging microstructural science aspects that aim to describe the transport properties of the random porous structure of currently used commercial rechargeable lithium-ion batteries are reviewed. Most of the existing work is based on the Bruggeman relationship, which underestimates the transport resistance in porous electrodes due to the particle shape anisotropy and randomness in orientation. A two-dimensional OOF model was developed to quantify the transport for various electrode morphologies. Two possible electrode microstructure-optimizing approaches are presented to lower the lithium-ion transport resistance: a) Preparation of perfectly spherical LiMn2O4 particles through an emulsion-gel method. Here, a manganese acetate-based precursor will be heat-treated and further cast into 13mm diameter disk-shaped electrodes; and b) Centrifugal slip casting of morphologically anisotropic particles to orient the active material in the low tortuosity direction. The anisotropic slurry of LiMn2O4 will be cast into straight channel architectures to provide minimal tortuosity in the direction of lithium-ion transport. Date: Thursday, June 27, 2013 Time: 8:45 A.M. Place: ARMS 3109 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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FW: Seminar Notice: D. Chung, MS Final Exam, Tue. 6/25/13, 1:30 pm, ARM 1021
by Stacey, Lisa A 18 Jun '13

18 Jun '13

MATERIALS SCIENCE AND ENGINEERING SEMINAR The Effect of Microstructure on the Performance of Li-Ion Porous Electrodes By: Ding-Wen Chung Master of Science Final Examination Advisor: Prof. R. E. Garcia ABSTRACT By combining X-ray tomography data and computer-generated porous electrodes, the impact of microstructure on the energy and power density of lithium-ion batteries is analyzed. Specifically, for commercial LiMn2O4 electrodes, results indicate that a broad particle size polydispersity of active material delivers up to two times higher energy density than monodisperse-sized particles for low discharge rates, and a monodisperse particle size distribution delivers the highest energy and power density for high discharge rates. The limits of traditionally used microstructural properties such as tortuosity, reactive area density, particle surface roughness, morphological anisotropy were tested against degree of particle size polydispersity thus enabling the identification of optimal porous architectures. The effects of critical battery processing parameters, such as layer compaction and carbon black were also rationalized in the context of electrode performance. While a monodisperse particle size distribution exhibits the lowest possible tortuosity and three times higher surface area per unit volume with respect to an electrode conformed of polydisperse particle size distribution, comparable performance can be achieved by polydisperse particle size distributions with degrees of polydispersity less than one fifth of the average particle size. The use of non-spherical particles raises the tortuosity by as much as three hundred percent, which considerably lowers the power performance. However, the use of favorably aligned particles can maximize power performance, particularly for high C-rate applications. Date: Tuesday, June 25, 2013 Time: 1:30 P.M. Place: ARMS 1021 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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Fwd: Snacking and Blood Pressure Study
by Donna Bystrom 07 Jun '13

07 Jun '13

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REMINDER: Seminar Notice: E. Walker, PhD Prelim Pt I, Thur. 6/6/13, 9:00 am, ARMS 3115
by Stacey, Lisa A 05 Jun '13

05 Jun '13

MATERIALS SCIENCE AND ENGINEERING SEMINAR Surface Modification of Nitinol Medical and Dental Implants for Improved Biocompatibility and Corrosion Resistance By: Emily K. Walker Ph.D. Prelim Exam - Part I Advisor: Prof. J. P. Allain ABSTRACT The use of metal alloys in dental, orthopedic, and vascular implants is ubiquitous. Metals have many advantages over ceramics and polymers in terms of mechanical properties, however corrosion is a persistent problem. Nickel-titanium alloys, which go by the trade name of Nitinol, are of particular interest in the medical and orthodontic fields due to their unique mechanical properties, good biocompatibility, and good corrosion resistance. Ion leaching is a major concern with any metallic implant, however, and nickel in particular is especially harmful to cell metabolism. In addition, Nitinol is also susceptible to localized corrosion, such as pitting. In order to prevent nickel leaching and localized corrosion of Nitinol implants, many surface modifications have been explored. Chemical modification, ion implantation, coating deposition, and electropolishing have all been explored with varying degrees of success. The results in the literature from these studies are somewhat inconsistent, so a reliable technique for improving the implant surface without affecting its mechanical properties is desired. Date: Thursday, June 6, 2013 Time: 9:00 A.M. Place: ARMS 3115 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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Updated Emergency Contact Info
by Stacey, Lisa A 04 Jun '13

04 Jun '13

MSE Department, If you have any changes or updates to your confidential Emergency Contact Information Sheet which we keep on file here in the department, please contact me. Also, if you have not completed a form since your arrival, please let me know that as well. I will be happy to leave a blank form in your mailbox. Thank you, Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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