The Waldemar T. Ziegler Award Winners 2016

Sullivan, Sylvia; Han, Rebecca

Title:

The Waldemar T. Ziegler Award Winners 2016 Importance of Updraft Velocity to Cloud Ice Crystal Formation Computational Characterization of Disorder and Heterogeneity in Bulk MOF Structures

dc.contributor.author	Sullivan, Sylvia
dc.contributor.author	Han, Rebecca
dc.contributor.corporatename	Georgia Institute of Technology. School of Chemical and Biomolecular Engineering	en_US
dc.date.accessioned	2016-11-02T20:26:04Z
dc.date.available	2016-11-02T20:26:04Z
dc.date.issued	2016-10-26
dc.description	Presented on October 26, 2016 from 4-5 p.m. in room G011 of the Molecular Science and Engineering Building on the Georgia Tech campus.	en_US
dc.description	Runtime: 47:24 minutes	en_US
dc.description.abstract	Importance of Updraft Velocity to Cloud Ice Crystal Formation, Sylvia Sullivan - The number and size of ice crystals and liquid droplets within a cloud determine its radiative impact on the Earth. To reduce the uncertainty associated with this cloud radiative forcing, simulations were performed with two global climate models to understand which inputs to the cloud system are most influential on crystallization therein: the updraft velocity, as a source of supersaturation and equivalent to a temperature ramp, or the aerosol number, as a sink of supersaturation and equivalent to a seed loading. In particular, attribution metrics are calculated using an efficient and robust automatic differentiation technique. These metrics show that updraft velocity is the controlling factor for realistic formulations and that predictions of cloud ice crystal number will be improved by more frequent updraft measurements at low latitudes and altitudes.	en_US
dc.description.abstract	Computational Characterization of Disorder and Heterogeneity in Bulk MOF Structures, Rebecca Han - Metal organic frameworks (MOFs) are an important class of microporous materials used in sieving, separations, and catalysis. Despite offering tunable pore size and functionalization, MOFs are limited in industrial applications by their tendency to degrade in humid and acid gas environments. We aim to characterize disorder and heterogeneity in bulk MOF structure based on the hypothesis that degradation begins at defect sites, as occurs in zeolites and metals. Two representative systems are considered, zeolitic imidazolate frameworks (ZIFs) and Zn2(1,4-BDC)2 (Dabco) (DMOF), because their ideal structures are wellstudied without much knowledge of the realistic materials. We establish evidence for thermodynamically favorable stacking faults in hypothetical ZIF polymorphs and correlate defect density to XRD spectra. We can also use simulations to elucidate the short range order in a threecomponent ZIF system and predict impact of linker distribution on pore window size or molecular diffusion. In comparison, DMOF is a mixed-linker framework inherently constructed of two ligand species. Our goal is to identify energetically accessible defects in the bulk structure and estimate their prevalence. This understanding will allow us to interpret literature observations of DMOF stability where the precise mechanisms remain unknown.
dc.format.extent	47:24 minutes
dc.identifier.uri	http://hdl.handle.net/1853/56001
dc.language.iso	en_US	en_US
dc.publisher	Georgia Institute of Technology	en_US
dc.relation.ispartofseries	School of Chemical and Biomolecular Engineering Seminar Series	en_US
dc.relation.ispartofseries	School of Chemical and Biomolecular Engineering Seminar Series
dc.relation.ispartofseries	Ziegler Awards
dc.subject	Attribution analysis	en_US
dc.subject	Climate modeling	en_US
dc.subject	Clouds	en_US
dc.subject	Computation	en_US
dc.subject	Defect	en_US
dc.subject	Degradation	en_US
dc.subject	DFT	en_US
dc.subject	Ice crystals	en_US
dc.subject	MOF	en_US
dc.subject	ZIF	en_US
dc.title	The Waldemar T. Ziegler Award Winners 2016	en_US
dc.title	Importance of Updraft Velocity to Cloud Ice Crystal Formation
dc.title	Computational Characterization of Disorder and Heterogeneity in Bulk MOF Structures
dc.type	Moving Image
dc.type.genre	Lecture
dspace.entity.type	Publication
local.contributor.corporatename	School of Chemical and Biomolecular Engineering
local.contributor.corporatename	College of Engineering
local.relation.ispartofseries	School of Chemical and Biomolecular Engineering Seminar Series
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