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Events for October 23, 2018
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PhD Defense
Tue, Oct 23, 2018 @ 11:00 AM - 12:00 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Speaker: Mr. Anyi Zhang , PhD Student, CHE
Talk Title: 'Nanostructure Design of Sulfur Cathodes and Lithium Metal Anodes for Lithium Ion Batteries
Abstract: Lithium ion batteries (LIBs) have been successfully used in portable electronics and electric vehicles for many years. Although the demand for high energy density keeps increasing, the existing commercial LIB systems are getting close to their theoretical capacity limits. In order to push the energy density to an even higher level, lithium sulfur (Li-S) batteries attract a lot of attention due to their high energy density and low cost. In this thesis, I will discuss the current challenges we are facing in Li-S battery development and our proposed solutions to address those issues using nanostructure design.
I will first present our accomplishment to enhance the S cathode performance. We have developed a scalable and inexpensive design for S cathode by capping a flexible gel polymer / carbon nanofiber (CNF) composite membrane onto a free-standing and binder-free CNF + Li2S6 cathode, thus forming a three-dimensional (3D) structural design. While the CNF network was used as the current collector and S holder to overcome the insulating nature and volume expansion of S, the composite membrane composed of a gel polymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and CNF additive was used as an interlayer to trap polysulfides and recycle remaining S species, leading to high specific capacity and long cycle life.
Next, I will talk about our achievement for stable Li metal anodes. We have demonstrated a distinctive design for dendrite-free deposition of Li by modifying the Cu current collector with a 3D CNF network. Due to the large surface area and high conductivity of the CNF network, Li metal can insert into and deposit onto CNF directly and no dendritic Li metal was observed, leaving a flat Li metal surface. The scalable preparation method and impressive results achieved here demonstrated the potential of applying our design in the development of dendrite-free Li metal anodes in future.
In addition, I will also present my research to further improve the performance of Li metal anodes. We have proposed a novel design of 3D interconnected graphene (IG) framework synthesized with the help of nickel (Ni) microspheres for stable Li metal anodes. The as-prepared IG framework consisted of multiple stacks of two-dimensional (2D) graphene layers and plenty of hollow graphene microspheres in between, and thus provided protective layers on the top to suppress lithium dendrites, sufficient surface area to reduce the effective current density, as well as ion channels for fast Li transport. This strategy of vertically stacking 2D materials provides a novel approach towards dendrite-free Li metal anodes for the next-generation energy storage systems.
Host: Dr. Chongwu Zhou
Location: Ronald Tutor Hall of Engineering (RTH) - 306
Audiences: Everyone Is Invited
Contact: Karen Woo/Mork Family
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Resume Lab - Bring your Laptop!
Tue, Oct 23, 2018 @ 01:00 PM - 02:00 PM
Viterbi School of Engineering Career Connections
Workshops & Infosessions
Labs are an activity where you can work on your resume in the presence of a career advisor to get tips on the spot.
Bring your Laptop!
For more information about Labs & Open Forums, please visit viterbicareers.usc.edu/workshops.Location: Ronald Tutor Hall of Engineering (RTH) - 211
Audiences: Everyone Is Invited
Contact: RTH 218 Viterbi Career Connections
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Epstein Institute Seminar - ISE 651
Tue, Oct 23, 2018 @ 03:30 PM - 04:50 PM
Daniel J. Epstein Department of Industrial and Systems Engineering
Conferences, Lectures, & Seminars
Speaker: Dr. Julie Swann, Professor and Dept. Chair, North Carolina State University
Talk Title: Engineering Modeling to Assist in Eradication of Guinea Worm
Host: Dr. Sze-chuan Suen
More Information: October 23, 2018.pdf
Location: Ethel Percy Andrus Gerontology Center (GER) - 206
Audiences: Everyone Is Invited
Contact: Grace Owh
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CS Colloquium: Ioannis Mitliagkas (University of Montréal) - Negative Momentum for Improved Game Dynamics
Tue, Oct 23, 2018 @ 03:30 PM - 04:50 PM
Thomas Lord Department of Computer Science
Conferences, Lectures, & Seminars
Speaker: Ioannis Mitliagkas, University of Montréal
Talk Title: Negative Momentum for Improved Game Dynamics
Series: Computer Science Colloquium
Abstract: Games generalize the single-objective optimization paradigm by introducing different objective functions for different players. Differentiable games often proceed by simultaneous or alternating gradient updates. In machine learning, games are gaining new importance through formulations like generative adversarial networks (GANs) and actor-critic systems. However, compared to single-objective optimization, game dynamics are more complex and less understood. In this talk, I will present recent research on the momentum dynamics of differentiable games. We will see an analysis of a simple differentiable game, which suggests that a negative momentum term can sometimes improve convergence. Then we will see empirical results that alternating gradient updates with a negative momentum term achieves convergence on the notoriously difficult to train saturating GANs.
This lecture satisfies requirements for CSCI 591: Research Colloquium.
Biography: Ioannis Mitliagkas is an assistant professor in the department of Computer Science and Operations Research (DIRO) at the University of Montréal, and member of MILA. Before that, he was a Postdoctoral Scholar with the departments of Statistics and Computer Science at Stanford University. He obtained his Ph.D. from the department of Electrical and Computer Engineering at The University of Texas at Austin. His research includes topics in statistical learning and inference, focusing on optimization, efficient large-scale and distributed algorithms, statistical learning theory and MCMC methods. His recent work includes methods for efficient and adaptive optimization, studying the interaction between optimization and the dynamics of large-scale learning systems as well as understanding and improving the performance of Gibbs samplers. In the past he has worked on high-dimensional streaming problems and fast algorithms and computation for large graph problems.
Host: Fei Sha
Location: Henry Salvatori Computer Science Center (SAL) - 101
Audiences: Everyone Is Invited
Contact: Computer Science Department
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Deepcurrent Hands-on Machine Learning Series Lesson #2
Tue, Oct 23, 2018 @ 07:30 PM - 08:30 PM
Viterbi School of Engineering Student Organizations
Workshops & Infosessions
RSVP: https://goo.gl/forms/stHImLYaTPvWdEl22
In Lesson #2, we will continue to delve deeper into the problem of predicting taxi fares in NYC. If you haven't already, you can download the lesson notebooks from this GitHub repo.
*This series is in high demand, so we encourage you to RSVP as soon as possible.Location: Montgomery Ross Fisher Building (school Of Social Work) (MRF) - 340
Audiences: Everyone Is Invited
Contact: AAAI at USC
