Date: Tuesday, September 1, 2026
Time: 2:00 – 4:00 PM EST
Location: Caddell Building, Conference Room 212 & Microsoft Teams
Microsoft Meeting Link:
https://teams.microsoft.com/meet/275012286837302?p=tYjHzReQ3Ao5blaC1O
Meeting ID: 275 012 286 837 302
Passcode: fg7aW3gx
Committee:
Title: Performance Evaluation of Geopolymer Mixes with Alternative Precursors: Mechanical, Microstructural, Durability, and Sustainability Insights
Abstract
Geopolymers, synthesized through the alkali activation of aluminosilicate precursors, have emerged as promising alternatives to ordinary Portland cement (OPC) because of their potential for lower carbon emissions, competitive mechanical and durability performance, and enhanced resistance to elevated temperatures. Geopolymer are a family of alumino-silicate binders, which is the result of an inorganic polycondensation reaction; a so-called geopolymerisation. Such reaction yields an amorphous to semicrystalline three-dimensional aluminosilicate frameworks with the general empirical formula of Mn{−(SiO2)z–AlO2−}n. wH20 - where M is a charge-balancing cation (e.g., Na⁺, K⁺, or Ca²⁺), n is the degree of polycondensation, and z is the Si/Al molar ratio governing geopolymer concrete properties – similar to conventional cement. Although established geopolymer cement commonly rely on aluminosilicate precursors such as fly ash (FA), ground-granulated blast-furnace slag (GGBFS), and metakaolin (MK), each precursor presents distinct limitations related to reactivity, material availability, compositional variability, cost, as well as environmental sustainability and optimization. For instance, FA shows source-dependent compositional variability - reporting up to 25% variation in strength across FA sources, and slow ambient-cured strength development, while GGBFS, despite high reactivity, can exhibit drying shrinkage 2–3 times that of OPC. MK provides more consistent reactivity but has high liquid demand and requires energy-intensive calcination (600–900 °C). Supply is also increasingly constrained: U.S. FA production declined by ~68% from 2002 to 2024, while the shift toward electric-arc-furnace steelmaking reduces availability of GGBFS. These limitations motivate hybrid geopolymer systems combining abundant natural and industrial precursors to exploit complementary physicochemical properties while mitigating individual precursor deficiencies. Analogous to the multi-component strategy of limestone calcined clay cement (LC3), optimized precursor combinations could achieve competitive engineering performance with reduced environmental and economic burdens. Therefore, this study establishes a pathway for translating alternative geopolymer precursors into construction-ready concrete, beginning with precursor reactivity and reaction mechanisms, followed by systematic mixture design, performance and durability validation, and environmental and economic evaluation. Ultimately, these efforts aim to identify a technically robust, low-impact, and cost-competitive binder with demonstrated potential for field implementation.
Toward this goal, a state-of-the-art review was first conducted to synthesize recent advances in the selection and application of commonly used geopolymer precursors, including FA, GGBFS, and MK, with particular emphasis on their chemical composition and reactivity, geopolymerization mechanisms, microstructural evolution, engineering performance, and system-level sustainability, as well as the key physicochemical factors governing their early-age behavior and long-term durability. The findings showed that performance is particularly governed by the combined effects of precursor chemistry, activator composition, and curing conditions, with FA- and GGBFS-based systems exhibiting distinct reaction pathways dominated by N–A–S–H and C–A–S–H generations, respectively. While both systems demonstrated mechanical and durability performance comparable to or better than OPC, GGBFS-based geopolymer generally exhibited lower energy demand and emissions. Importantly, the review highlighted the role of calcium-rich chemistry in GGBFS-based geopolymer promote C–A–S–H formation and strength development. Together with the need to reduce dependence on conventional precursors, this finding motivated the exploration of alternative calcium-rich industrial materials such as calcium carbide residue (CCR).
Informed by this review, the first research work investigates CCR, a high-calcium by-product of acetylene production, as a supplementary precursor to partially replace GGBFS and MK in binary and ternary geopolymer binder systems. The goal is to develop a blended geopolymer using an abundant Ca-rich precursor to reduce GGBFS demand while enhancing precursor reactivity and engineering performance while minimizing reliance on FA and MK. Findings showed that selected CCR replacement levels, particularly at lower dosage, achieved strengths comparable to the GGBFS control, while ternary CCR–MK blends retained 96–99% of the control 28-day strength. Microstructural analysis revealed that CCR promoted the formation of hybrid reaction products, while its combination with MK facilitated matrix densification and the development of a more refined geopolymer microstructure. At 20% CCR replacement, embodied carbon decreased from 574.6 to 560.6 kg CO₂-e/m³, while material cost decreased by approximately 6%. These findings demonstrated that CCR can be valorized as a Ca-rich supplementary material to reduce GGBFS consumption, embodied carbon, and material cost while maintaining performance. However, CCR availability is inherently linked to calcium-carbide-based acetylene production, resulting in regional supply constraints and potentially higher transportation costs and motivating the investigation of more widely available natural precursors. More fundamentally, the changes in reaction products and microstructural development observed with alternative precursor substitution demonstrate that replacing conventional precursors can significantly alter geopolymerization pathways. This highlights a critical knowledge gap in how precursor chemistry controls dissolution kinetics and, consequently, gel formation and long-term network development.
Furthermore, a second mechanistic study, guided by computational modeling, was conducted to establish the relationship between precursor dissolution rate and kinetics and the subsequent evolution and reorganization of the geopolymer network. Real-time measurements using inductively coupled plasma mass spectrometry (ICP-MS) showed rapid early dissolution of Al and Si, with initial rates of approximately 0.605 and 4.697 μmol L⁻¹ s⁻¹, respectively, followed by a transition toward polycondensation. Multiscale characterization further revealed progressive gel growth and surface densification, with surface roughness decreasing by approximately 39% by 7 days and the Si/Al ratio stabilizing at about 1.7 – 1.8 as a dense and chemically stable N–A–S–H network developed. These findings showed that early dissolution behavior directly influences subsequent gel chemistry and structural development, providing reaction-level insight for selecting and combining precursors in the hybrid system.
This understanding motivated a hybrid precursor system combining highly reactive MK with lower-energy pumice and limestone powder (LP) as the third research objective. MK provides readily available Si and Al, while pumice supplies additional aluminosilicates for continued polycondensation and LP contributes Ca alongside filler and nucleation effects. Their complementary chemistry promotes interactions between N–A–S–H and Ca-containing gels, providing a basis for optimizing reaction kinetics, microstructural development, engineering performance, and overall binder sustainability. To systematically evaluate precursor interactions across the ternary composition space, a full-range augmented simplex lattice design was deployed to establish composition–property relationships for flowability, compressive strength, sorptivity, and drying shrinkage. Multi-response optimization identified a balanced mixture containing approximately 7.4% MK, 75.6% pumice, and 17.0% LP. Experimental validation yielded 106.25% flowability, 3.62 ksi 28-day compressive strength, 0.0447 mm/√s sorptivity, and 0.056% drying shrinkage. Life-cycle assessment showed a GWP of ~374 kg CO₂-e/m³, compared with 543 and 689 kg CO₂-e/m³ for MK-based GPC and OPC, respectively, demonstrating the environmental benefit of increased pumice and LP substitution. However, transport and dimensional-stability responses were highly composition-dependent, with sorptivity varying by >13-fold (0.0062–0.0823 mm/√s) and drying shrinkage by >3-fold (0.042–0.134%), contributing to larger prediction errors during model validation.
To reduce variability and prediction errors in the initial optimization, the composition space around the initial optimized mixture composition was refined to 5–20% MK, 70–85% pumice, and 10–25% LP, leading to the fourth research goal focused on refining and validating the optimized ternary system. This constrained optimization targets <10% deviation between predicted and experimental responses while identifying a mixture with improved overall performance, including the flowability, compressive strength, sorptivity, and drying shrinkage. The optimized system subsequently undergo integrated life-cycle and techno-economic assessments (LCA- TEA), benchmarked against conventional geopolymer systems to evaluate its environmental impact, production cost, and circular economy. The optimized mixture (9.8% MK, 77.1% pumice, 13.1% LP) achieved 105.48% flowability, 3.83 ksi 28-day strength, 0.042 mm/√s sorptivity, and 0.057% drying shrinkage, with prediction errors of 0.30–5.80%. XRD, FTIR, and SEM-EDS attributed this balanced performance to a dense, silica-rich hybrid C-(N)-A-S-H matrix with moderate Ca incorporation. Compared with conventional geopolymer systems, the mixture demonstrated competitive engineering performance while reducing cost to $286.30/m³ (58.8% below MK-based GPC) and GWP to 378.3 kg CO₂-eq/m³ (30.4% and 10.9% below MK- and slag-based systems, respectively). Strength-normalized analysis further demonstrated improved cost and carbon efficiency relative to MK- and FA-based systems.
Finally, future work will advance the final optimized binder toward field and application-scale validation as a repair or overlay /concrete pavement. Bond performance with existing concrete will be evaluated through pull-off testing in accordance with ASTM C1583 and slant-shear testing based on ASTM C882, together with other durability testing, to determine its suitability for practical repair and overlay applications. Overall, this research progresses from understanding conventional and alternative precursor behavior to mechanism-informed, sustainability-guided mixture development, optimization, and application-scale validation, with the goal of advancing technically viable, lower-carbon geopolymer binders for practical construction applications.
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Ngoc Phuong Dung Ho
School of Chemistry and Biochemistry
Advisor: Advisor: James C. Gumbart (School of Physics)
Open to the Community
Across Scales of Regulation: Decoding How Small Molecules Reshape Protein Dynamics, Assembly, and Phase Separation
Tuesday, September 1, 2026, at 2:00 pm
Howey Physics Building, Room W401
Committee Members:
Jeffrey Skolnick (School of Biological Sciences)
Andrew McShan (School of Chemistry and Biochemistry)
Nael A. McCarty (Emory University)
Abstract:
Small molecules modulate essential biological processes across diverse spatial and temporal scales, from regulating intramolecular channel gating to remodeling dynamic oligomeric interfaces and dictating the mesoscale material properties of biomolecular condensates. Although structural biology has resolved numerous therapeutic binding pockets, static structures alone cannot explain how ligand binding alters the dynamic conformational ensembles that govern functional outcomes. This thesis establishes an integrated computational and biophysical framework which combines all-atom molecular dynamics, machine-learning-assisted conformational sampling, coarse-grained modeling, and experimental validation to decode small-molecule regulation across distinct biological hierarchies. By elucidating potentiator-driven gating in cystic fibrosis transmembrane conductance regulator (CFTR) channels, targeting transient dimer interfaces in tumor necrosis factor alpha (TNF-α), and resolving drug-induced single-chain collapse in fused in sarcoma (FUS) condensates, this work connects atomistic conformational shifts to emergent mesoscale organization, providing rational principles to accelerate targeted therapeutic discovery.
]]>Committee:
Dr. Alexandros Daglis, CS, Chair, Advisor
Dr. Moinuddin Qureshi, ECE
Dr. Ada Gavrilovska, CoC
Dr. Richard Vuduc, CSE
Dr. Jovan Stojkovic, UT Austin
]]>Committee:
Dr. Ali Adibi, ECE, Chair, Advisor
Dr. Stephen Ralph, ECE
Dr. Benjamin Klein, ECE
Dr. John Cressler, ECE
Dr. Phillip First, Physics
]]>Committee:
Dr. Matthieu Bloch, ECE, Chair, Advisor
Dr. John Barry, ECE
Dr. Viveck Cadambe, ECE
Dr. Yanbao Zhang, ORNL
Dr. Robert Clark, Physics
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will propose a doctoral thesis entitled,
Structure–Property Relationships in Lead Halide Perovskites: From Phase Stability to Collective Optical Phenomena
On
Friday, August 28 at 10:00 a.m.
MRDC Room 4211
and/or
Virtually via MS Teams
https://teams.microsoft.com/meet/248586010524518?p=mgQvgezgjq0Ntoto7X
Committee
Prof. Juan-Pablo Correa-Baena – School of Material Science and Engineering (advisor)
Prof. Natalie Stingelin – School of Material Science and Engineering
Prof. Matthew Sfeir – School of Material Science and Engineering
Prof. Guoxiang (Emma) Hu – School of Material Science and Engineering
Prof. Ajay Ram Srimath Kandada – Wake Forest University, Department of Physics
Prof. Seth Marder – University of Colorado Boulder, School of Chemical and Biological Engineering
Abstract
Lead halide perovskites (LHPs) exhibit highly tunable structural and optical properties, yet their performance remains limited by phase instability in 3D systems and exciton–phonon interactions in low‑dimensional analogues. This thesis proposes to investigate how targeted chemical modifications at the organic–inorganic interface govern the ground‑state structural stability and excited‑state lattice response across perovskite dimensionalities. In Objective 1, molecular modulations of phosphonic acids will be used to probe how hydrogen‑bonding interactions stabilize the α‑FAPbI3 phase and suppress formation of the non‑perovskite phases. Objectives 2 and 3 will extend this framework to low‑dimensional perovskites, where the structure and dynamic motion of spacer cations dictate octahedral distortions, lattice flexibility, and exciton–phonon coupling. Objective 2 will establish how monodentate versus bidentate binding modalities and the chemical nature of the anchoring groups modulate the rigidity of the inorganic lattice and its susceptibility to photoinduced deformation, thereby tuning exciton dressing and the scattering pathways that govern dephasing. Building on these insights, Objective 3 will examine how lattice flexibility influences the emergence of superfluorescence by comparing phenethylammonium, chlorinated‑phenethylammonium, and benzene‑based bidentate cations, determining whether molecular control over lattice dynamics can modulate coherence decay and the conditions required for cooperative emission. Together, these proposed studies aim to reveal how organic–inorganic interactions regulate structural stability and photoinduced lattice dynamics, establishing molecular‑level design principles for advancing the optoelectronic and quantum photonic capabilities of lead halide perovskites.
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will propose a doctoral thesis entitled,
Designing catalysts for electrochemical conversion of waste to value-added products
On
Monday, August 31 at 2:30 p.m.
MRDC Room 3515
Committee
Prof. Marta C. Hatzell – School of Chemical and Biomolecular Engineering, George W. Woodruff School of Mechanical Engineering (advisor)
Prof. Faisal M. Alamgir– School of Materials Science and Engineering (co-advisor)
Prof. Guoxiang (Emma) Hu – School of Materials Science and Engineering
Prof. Preet M. Singh – School of Materials Science and Engineering
Dr. Shawn M. Dirk – Sandia National Laboratories
Abstract
Nitrogen- and carbon-containing species circulate through Earth's ecosystems and play essential roles in sustaining life. Nitrogen is a crucial nutrient, while carbon regulates the climate on Earth. However, anthropogenic activities have disrupted these natural cycles, among other factors, through the widespread application of fertilizers and the extensive use of fossil fuels. As a consequence, water bodies are poisoned due to an increase in nutrient concentration. The chemical industry has disrupted the nitrogen and carbon cycle, which is exemplified by the Haber-Bosch process. The Haber-Bosch process synthesizes ammonia, a key chemical in fertilizer production that relies on fossil-derived feedstocks. The excess of nutrients in fertilizers results in a high nitrogen concentration in wastewater, specifically as nitrate. Wastewater treatment plants process wastewater into sludge, but do not transform the sludge into value-added products. The nitrogen that persists in the sludge after treatment (or digestion) is usually in the form of glycine. The present thesis proposes the synthesis of ammonia through the electrochemical conversion of waste, nitrate and glycine, as a strategy to replace fossil-derived resources with waste-derived feedstocks, thereby contributing to the restoration of a more sustainable and circular nitrogen and carbon cycle.
Nitrate reduction and glycine oxidation may yield several products in addition to ammonia. Thus, achieving an efficient electrochemical conversion of these waste streams requires a fundamental understanding of the reaction mechanisms and rational catalyst design to precisely control the reaction selectivity to ammonia. Regarding nitrate reduction, transition metal hydrides are hypothesized to enhance ammonia selectivity by increasing hydrogen availability at the catalyst surface. However, the role of interstitial hydrogen incorporated within metal lattices remains largely unexplored. However, the role of interstitial hydrogen incorporated within metal lattices remains largely unexplored. This study aims to advance the understanding of interstitial metal hydride catalysts and their potential in catalytic applications. Glycine oxidation can proceed through either C–C or C–N bond cleavage, producing predominantly C₁ or C₂ products, respectively. The factors that govern the competition between these pathways on transition metal surfaces remain poorly understood. Therefore, this work will elucidate the reaction pathway of glycine oxidation on nickel, identify key reaction intermediates associated with C₂ product formation, and evaluate the influence of reaction conditions on C–C and C–N bond cleavage. Overall, this thesis seeks to establish catalyst design principles for the electrochemical conversion of nitrogen-containing waste streams into value-added products, contributing to the remediation of nitrogen and carbon cycles.
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will propose a doctoral thesis entitled,
Fluidic Release and Adaptive Interconnection for Distributed Micromodular Manufacturing
On
Thursday, August 27 at 11 am.
Love Building Room 210
and/or
Virtually via MS Teams
Join: https://teams.microsoft.com/meet/2544541598578?p=fO1Hkfy2luTTnpDsv7
Meeting ID: 254 454 159 857 8
Passcode: BX26Mq2n
Committee
Dr. Michael Filler- School of Chemical and Biomolecular Engineering (Advisor)
Dr. Eric Vogel - School of Materials Science and Engineering (Co-advisor)
Dr. Victor Breedveld - School of Chemical and Biomolecular Engineering
Dr. Anju Toor - School of Materials Science and Engineering
Dr. Juan-Pablo Correa-Baen - School of Materials Science and Engineering
Abstract
The semiconductor industry has achieved extraordinary control over device performance at the wafer scale, but no existing route reconciles that performance with the substrate flexibility, accessibility, speed, and heterogeneous integration needed for on-demand fabrication of application-specific microelectronics. Fluidic release and adaptive interconnection enable microchiplets, individually fabricated semiconductor devices, to be released into suspension, deposited stochastically, identified by computer vision, and interconnected according to their realized position. However, widespread implementation is limited by challenges in substrate-dependent electrical performance, microchiplet misalignment, scalable release, and control over microchiplet design across the integrated process. Addressing these challenges requires a comprehensive approach spanning substrate compatibility, adaptive interconnection, scalable release and transport, and integrated process design, pursued through four research aims. The first determines which interfacial properties govern adhesion after transfer, establishing design rules for microchiplet transfer across substrate classes. The second addresses microchiplet misalignment through automated, computer-vision-based detection and adaptive routing that wires microchiplets into functional circuits. The third establishes scalable microchiplet release and transport, identifying process conditions that balance release completeness against mechanical integrity. The fourth applies design-space variation across microchiplet size, shape, and process conditions, controlling release, placement, and orientation within the now-integrated flow. By integrating substrate characterization, adaptive interconnection, scalable release, and integrated process design, this work establishes a systematic framework for distributed, fluidic microelectronic manufacturing. The outcomes will provide practical design rules for microchiplet transfer, release, and deposition, enabling scalable, application-matched heterogeneous electronics.
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Student Name: Vanessa N. Psarras-Román
Thesis Title: Exploring Carbon Molecular Sieves (CMS) Capabilities and Performance as a Carbon Host for Lithium-Sulfur Battery Cathodes
Thesis Advisor: Dr. Ryan Lively
Thesis Co-Advisor: N/A
Committee Members: Dr. Julia Yang (ChBE), Dr. William Koros (ChBE), Dr. Paul Kohl (ChBE), Dr. Matthew McDowell (ME, MSE)
Date: 8/25/2026
Time: 10 AM
Location: Ford ES&T L1120
]]>Student Name: Haeyeon Choi
Thesis Title: Reduced-Space Global Optimization Algorithms for Flowsheet Models of CO2 Removal and Ammonium Recovery
Thesis Advisor: Joseph K. Scott
Thesis Co-Advisor: N/A
Committee Members: Nikolaos V. Sahinidis (ChBE, ISyE), Matthew Realff (ChBE), Fani Boukouvala (ChBE), Micah S. Ziegler (ChBE)
Date: 8/28/2026
Time: 10 a.m.
Location: Ford ES&T 2229
]]>Travis Harrison-Rawn
School of Chemistry and Biochemistry
Advisor: Lynn Kamerlin (School of Chemistry and Biochemistry)
Open to the Community
Loop dynamics of metabolically critical enzymes in mycobacterium tuberculosis
Tuesday, August 25, 2026 at 11:00am
Molecular Science and Engineering (MoSE), Room 1226
Committee Members:
JC Gumbart (School of Physics)
Raquel Lieberman (School of Chemistry and Biochemistry)
Andrew McShan (School of Chemistry and Biochemistry)
Abstract:
Tuberculosis (TB) is the most lethal infectious disease on the planet, taking more than 1.2 million lives per year. While the disease is curable, the pathogenic bacterium mycobacterium tuberculosis, is extremely durable and prone to developing multidrug resistance. The persistence of these variants is an ongoing threat to human health globally and the development of novel therapeutics is urgent.
We propose to computationally characterize enzymes with critical metabolic functions within the bacterium. We will perform physics-based simulations to model the conformational landscapes of triosephosphate isomerase (TPI) and indole-3-glycerol phosphate synthase (IGPS) which take part in glycolysis and tryptophan biosynthesis respectively.
Structurally, these proteins share a TIM-barrel fold with mobile loops that facilitate ligand coordination required for catalysis. To model these complex conformational changes, we will utilize enhanced sampling simulations in parallel with a dimensionality-reduction technique called time-lagged independent component analysis (tICA). Together, these tools allow us to sample and quantify rare loop transitions at an atomistic resolution. Alongside this approach, we will characterize the allosteric networks that govern these dynamics. Identifying critical allosteric hotspots will enable the screening of selective small molecules aiming to disrupt the loop dynamics essential for catalysis.
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