Xia, Rogers, and Henry Receive NSF CAREER Awards
Three Woodruff School faculty members recently won NSF CAREER Awards. These faculty members include Shuman Xia, Jonathan Rogers, and Asegun Henry. In addition, Assistant Professor of Aerospace Engineering Wenting Sun, who holds a joint appointment in the Woodruff School, was recently selected for an AFOSR Grant. Below you will find further information on each of these projects that have been awarded.
In Situ Nanomechanics of High-Performance Anode Materials for Sodium-Ion Batteries
Energy storage and release of sodium-ion battery electrodes involves a complex set of mechanical and electrochemical processes, including deformation, stress generation, mass transport, phase transformation, and chemical reaction. A fundamental understanding of the mechanics and its strong coupling with other physical phenomena is required to achieve breakthroughs in the sodium-ion battery technology. The research objective of this award is to develop an in situ nanomechanical testing platform for the constitutive characterizations of sodium-ion battery electrode materials. The experimental framework will be employed to investigate the in situ mechanics of sodiated/desodiated germanium and germanium-tin alloys, which are two promising high-performance anode materials for advanced sodium-ion batteries. The space- and time-resolved constitutive behaviors from experimental measurements will be incorporated into a continuum computational model for predictive simulations of the mechanical degradation and morphological evolution in solid electrode materials.
Causation in Dynamical Systems: Bridging the Gap Between Data Analytics and System Identification
Engineering Heat Conduction Through Alloys and Interfaces
The PGM was born out of the behaviors observed for perfectly pure crystalline materials, where all of the collective vibrations look like sine waves, and it does a remarkable job at explaining a wide range of experimental measurements for thermal conductivity and thermal interface conductance. However, when a material becomes disordered, i.e., either compositionally (e.g., an alloy) or structurally (e.g., high defect density or an amorphous material), the collective vibrations change from looking like sine waves to vibrations in seemingly randomized directions. As a result, the PGM breaks down and there are a myriad of interesting unanswered scientific questions associated with how heat transfer occurs in collective vibrations that do not look like sine waves.
Professor Henry’s proposal delves deeply into the underlying physics of the collective vibrations that occur in alloys and at interfaces and specifically seeks to illustrate that it may be possible to achieve properties previously unimaginable based on PGM based intuition. Furthermore, the proposal includes several outreach efforts including the development of a mobile app that will allow the general public to interface with the research being conducted. Specifically, the mobile app will allow users to listen to sonified data from the studies being conducted in addition to the sounds of the elements of the periodic table. Since every substance is composed of atoms and atoms are always moving, it is possible to simply treat the time dependent motions of atoms as time varying audio signals (i.e., by scaling the time axis of the vibrations down by ~ 1 billion times). The app will therefore also serve as a teaching tool so users can learn the periodic table of elements by hearing the sounds they make.
See Professor Henry’s website (http://www.ase.gatech.edu/sonification-overview/) for example sounds of semiconductors and a recent gizmodo article (http://gizmodo.com/this-scientist-is-turning-every-element-in-the-periodic-1759423993) about sonifying the periodic table.
Sun's research team will focus on both the experimental and numerical investigation of explosive ozonolysis reactions - the spontaneous reactions between ozone and unsaturated hydrocarbons. The goal is to use his findings to control combustion for hypersonic vehicles.
Ultimately, Sun points out, his research will give engine designers a new arsenal of tools to produce hypersonically propelled aircraft - vehicles able to travel at speeds in excess of five times the speed of sound. "The Air Force is interested in this because it will allow them to reach any place on earth in two hours or less. There are lots of reasons why that is an important goal, worth the expense", Sun stated.