Feb
12

Materials Engineering Seminar

12:00 PM - 01:00 PM
Speare Hall
Address:
1008 Bullock Blvd, Socorro, NM

Laura de Sousa Oliveira, of the University of Wyoming, will present the Materials Engineering seminar. Her talk is "Atomistic Modeling of Phonon Transport."  

Noon Friday, Feb. 12, in Speare 113

Zoom Link:

https://zoom.us/j/91641115122?pwd=WWJLRmJZVXJFTVBXSE1Gd3RiNFZrZz09

The ability to control and manipulate heat goes hand in hand with human progress. This was the case in pre-history"when we mastered fire for cooking, heating and defense"and it continues to be true today. As devices get smaller and our ability to nanostructure materials improves, to predict and control heat transport in next-generation materials and devices, it becomes essential to develop an atomistic-level understanding of thermal transport. My research to date has focused on thermal transport at the atomistic scale, including classical molecular dynamics, ab initio approaches and heuristic models in a variety of materials. In this talk, I will discuss thermal transport in three types of bulk materials with a wide array of functionalities, applications and transport properties: graphite, nanoporous silicon, and metal"organic frameworks. Applications for these materials range from nuclear engineering, as is the case with graphite, to energy generation, and storage, among others. Classical molecular dynamics is especially useful to evaluate thermal transport in defect-laden structures. For instance, to advance our knowledge of the evolution of the microstructure of graphite while in service in a graphite-moderated nuclear reactor, I investigate how various point defects and concentrations thereof affect thermal transport. While a high thermal conductivity is ideal for a nuclear moderator, thermoelectric applications require very low thermal conductivities. Thermoelectric devices, which convert temperature differences into an electrical current and vice-versa, are a promising technology for waste heat recovery" approximately two-thirds of all the energy that is generated is lost as waste heat! The introduction of nanopores drastically reduces a material’s thermal conductivity, but there is not yet a clear understanding of why that is. Using large-scale molecular dynamics simulations (of hundreds of thousands of atoms), I study the effect of pore configuration on thermal transport to identify the most important mechanisms for thermal conductivity reduction in porous materials. Finally, we take a brief look at thermal transport in metal"organic frameworks (MOFs). MOFs are highly modular and have large surface areas and are therefore promising for numerous applications, including hydrogen storage and carbon sequestration. A simple geometric model of thermal conductivity is proposed as a heuristic for the quick evaluation of thermal transport in flexible MOFs, and a quantum-based approach is implemented to explore deviations from the heuristic, resulting in the discovery of emergent rattler modes and heat-focusing properties that can be switched on and off.