Department Events

Events

  • Nov
    16-30

    Weekly ChBE Seminar Series (Sossina Haile)

    McCormick-Chemical and Biological Engineering

    9:00 AM M345, Technological Institute

    EVENT DETAILS

    Title: Extracting Material Properties from Relaxation Experiments

    Abstract: Redox active oxides, with mixed ionic and electronic conductivity (MIEC), are critical components in a wide range of energy technologies, serving as electrodes in fuel cells and batteries, and as reactive substrates in solar-driven thermochemical reactors. Accurate knowledge of the surface reaction rate constant, , is essential for both optimal design of components using existing materials and rational discovery of new materials with enhanced catalytic activity. A variety of relaxation methods have been used extensively to determine . Such approaches rely on the change in some measurable property, most commonly conductivity, upon application of a step change in gas-phase oxygen partial pressure. Under the appropriate experimental conditions, the rate at which the property changes in response to the change in gas-phase oxygen chemical potential provides a direct measure of the material kinetic parameters. Here, we present several considerations relevant to accurate extraction of these parameters, with particular focus on identifying relaxation occurring due to thermodynamic rather than material kinetic reasons. Furthermore, while the electrical conductivity relaxation (ECR) method is one of the most widely employed relaxation techniques because of the ease with which high precision conductivity measurements can be made using samples of almost arbitrary dimensions, ECR is impractical for the evaluation of a material in which the change in conductivity in response to change in oxygen partial pressure is extremely small. For such materials mass relaxation emerges as a viable alternative measurement approach. To this end, we describe a high temperature mass relaxation apparatus based on a gallium phosphate piezocrystal microbalance that enables measurements at temperatures as high 700 °C.

    Sossina M. Haile is the Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University, a position she assumed in 2015 after serving 18 years on the faculty at the California Institute of Technology. She earned her Ph.D. in Materials Science and Engineering from the Massachusetts Institute of Technology in 1992. Haile’s research broadly encompasses solid state ionic materials and electrochemical devices, with particular focus on energy technologies. She has established a new class of fuel cells with record performance for clean and efficient electricity generation, and created new avenues for harnessing sunlight to meet rising energy demands. She has published more than 160 articles and holds 12 patents on these and other topics. Amongst her many awards, in 2008 Haile received an American Competitiveness and Innovation (ACI) Fellowship from the U.S. National Science Foundation in recognition of “her timely and transformative research in the energy field and her dedication to inclusive mentoring, education and outreach across many levels.”

    more less

    TIME Thursday, November 16, 2017 at 9:00 AM - 10:00 AM

    LOCATION M345, Technological Institute    map it

    ADD TO CALENDAR SHARE

    CONTACT Elizabeth Rentfro    elizabeth.rentfro@northwestern.edu EMAIL

    CALENDAR McCormick-Chemical and Biological Engineering

  • Nov
    29

    BTP Seminar Series, Dana Andersen

    McCormick-Chemical and Biological Engineering

    12:00 PM ITW Classroom, Ford Motor Company Engineering Design Center

    EVENT DETAILS

    TIME Wednesday, November 29, 2017 at 12:00 PM - 1:00 PM

    LOCATION ITW Classroom, Ford Motor Company Engineering Design Center    map it

    ADD TO CALENDAR SHARE

    CONTACT Emily Kocevar    e-kocevar@northwestern.edu EMAIL

    CALENDAR McCormick-Chemical and Biological Engineering

  • Nov
    30

    Weekly ChBE Seminar Series (Michael Wong)

    McCormick-Chemical and Biological Engineering

    9:00 AM M345, Technological Institute

    EVENT DETAILS

    TIME Thursday, November 30, 2017 at 9:00 AM - 10:00 AM

    LOCATION M345, Technological Institute    map it

    ADD TO CALENDAR SHARE

    CONTACT Elizabeth Rentfro    elizabeth.rentfro@northwestern.edu EMAIL

    CALENDAR McCormick-Chemical and Biological Engineering

  • Dec
    9

    Northwestern Engineering PhD Hooding and Master's Recognition Ceremony

    McCormick School of Engineering and Applied Science

    10:30 AM Ryan Family Auditorium, Technological Institute

    EVENT DETAILS

    TIME Saturday, December 9, 2017 at 10:30 AM - 12:00 PM

    LOCATION Ryan Family Auditorium, Technological Institute    map it

    ADD TO CALENDAR SHARE

    CONTACT Paula Straaton    p-straaton@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science