Talk Abstracts

Mitigating industrial carbon emissions requires technologies that operate efficiently under realistic flow, thermal, and chemical constraints, where separation and reaction processes are often tightly coupled. Many existing approaches rely on powder-based materials and packed-bed reactors, which impose fundamental limitations on pressure drop, heat management, and scalability. In this talk, I will present recent work on monolithic material platforms designed to address these challenges by decoupling structural transport properties from surface chemistry.

The talk will focus on how mesoscale architecture in washcoated monolithic materials governs gas transport, thermal behavior, and reactive performance under integrated capture–reaction conditions. By systematically varying operating parameters such as flow rate, temperature, and feed composition, this work identifies structure–function relationships that emerge in structured reactor environments. These results highlight both the opportunities and constraints of monolithic architectures and illustrate how reactor-relevant material design can enable more efficient and scalable approaches to carbon management across engineering applications.

In this talk, Dr. Khalid K. Osman will reflect on the research mission and evolving body of work of the Osman Lab, which sits at the intersection of infrastructure engineering, environmental justice, and community engaged research. His work is motivated by a central question of how infrastructure systems, particularly water and sanitation, can be designed, evaluated, and governed in ways that address historical harm, center lived experience, and respond to climate and social change. Drawing on projects across multiple U.S. cities, he will discuss how conventional engineering and regulatory frameworks often overlook critical dimensions of equity such as trust, affordability, and everyday experiences with infrastructure. He will highlight how community based participatory research, mixed methods, and sustained partnerships with community based organizations can expand what counts as evidence and lead to more grounded ways of evaluating system performance. The talk will weave together examples from household scale water quality monitoring, affordability and assistance programs, and risk communication during crises to show how social, institutional, and technical factors interact to shape infrastructure outcomes. Dr. Osman will also reflect on what inspired him to pursue this line of research, the commitments that guide his lab, and future directions including climate driven hazards, governance and policy design, and the development of scalable tools to support more equitable infrastructure decision making.

This study examines the effects of microbiome on activation of host regeneration processes. As an injury model, we utilized the Drosophila limb, which does not normally regenerate. We find that supplementing Lactobacillus brevis ATCC 367 promotes activation of regeneration processes in the amputated limb, as characterized by change in wound healing, enhanced tissue survival, and eventually partial regrowth of the limb. To investigate how L. brevis influences host regeneration, we combined genome-scale metabolic modeling with experimental measurements, and found that L. brevis secretes the amino acid ornithine. Flies fed with L. brevis indeed show higher extract levels of ornithine and altered levels of enzymes that metabolize ornithine. Directly administering ornithine to the flies promotes regeneration processes in the limb. In summary, this study presents evidence that supplying a bacteria that secretes ornithine can promote regeneration processes in a host organ that does not normally regenerate. Further, L. brevis supplementation can be performed prior to injury, opening up the possibility of prophylactically improving response to injury.  

Gallium arsenide (GaAs) solar cells offer among the highest photovoltaic efficiencies but remain limited by high manufacturing costs. Reducing cost while maintaining performance is therefore critical for large-scale deployment.

Here we demonstrate a simple, low-cost method to grow a thin gallium nitride (GaN) passivation layer directly on GaAs using ammonium chloride and gallium sources in a standard tube furnace. This approach avoids the complex gas-handling infrastructure required for conventional GaN growth, providing a scalable and economical alternative. Material characterization confirms the formation of a polycrystalline GaN layer that reduces surface recombination.

State-of-the-art devices for the Caltech Space Solar Power Project currently operate at 15.5% efficiency. Modeling suggests that improved surface passivation alone could yield a 1–2% absolute efficiency gain, moving performance toward the ~20% efficiency target required for SSPP viability. Ongoing work focuses on integrating this passivation approach into device structures to evaluate its impact on photovoltaic performance.

As AI-generated synthetic media becomes increasingly indistinguishable from authentic content, understanding how humans perceive and evaluate artificial stimuli is both a scientific and societal imperative. This talk presents findings from neuroimaging and behavioral experiments investigating whether the human brain contains reliable signals that distinguish real from AI-generated faces.

Using fMRI and machine learning-based neural decoding, we show that distinct patterns of brain activity emerge when participants view authentic versus synthetic faces — even when behavioral judgments approach chance. Multivariate classification of neural responses identifies regions involved in authenticity perception, revealing that the brain processes subtle cues related to artificiality that may not reach conscious awareness. Behavioral results further characterize the conditions under which human detection performance degrades, particularly as generative models improve in photorealism.

In the local universe, low-mass irregular galaxies (Mstar ~ 109 Msun) and Milky Way mass (Mstar ~ 1010 Msun) disk galaxies are typically star-forming, while massive, elliptical galaxies (Mstar ~ 1011 Msun) are usually “quenched” or not forming stars. Simulations have shown that supermassive black hole (SMBH) feedback shuts down star formation in these massive galaxies and is required to reproduce the observed galaxy population at low redshift. It is still not fully understood how SMBH feedback corresponds to galaxy morphology in detail. To elucidate the effects of SMBH feedback on galaxy morphology, we analyze a suite of 9 Milky Way-mass galaxies with live SMBH feedback from the “Feedback In Realistic Environments” (FIRE) simulations. Using circularity (𝜖 = Jz/Jc(E)) as a proxy for morphology, we investigate how heating and outflows/winds from SMBH feedback disrupt star formation and the subsequent morphological evolution of galaxies over cosmic time. We find that SMBH feedback reduces star formation across three evolutionary phases corresponding to spheroidal, thick disk, and thin disk morphologies. Notably, SMBH feedback targets the disk formation phase, resulting in a more spheroidal shape

How to track the health of an aquifer we cannot see or directly access? I work at the crossroads of seismology and hydrology to address this challenge.

By analyzing permanent but subtle ground vibrations recorded in California’s Central Valley, I track mechanical weakening driven by hydrologic perturbations (e.g. the water cycle, extreme weather events), to monitor the ever-changing health of aquifer systems. My goal is to quantify small variations in seismic wave propagation velocities (dv/v), which are highly sensitive to changes in effective stress. Leveraging coda wave interferometry methods, I explore how dv/v measurements can serve as proxies for basin-scale effective stress redistribution, poroelastic response and the accumulation or relaxation of subsurface damage. 

I present preliminary results and ways in which my research helps gain better understanding of aquifer systems mechanics.