Maia Abiani¹

Undergraduate Class of 2026
Principal Investigator: Michael Mueller¹

¹ Department of Mechanical and Aerospace Engineering

Evaluating Ammonia Combustion Concepts

Abstract
Ammonia is a promising zero-carbon alternative fuel, however, compared to hydrocarbon fuels, ammonia has poor combustion characteristics. The primary challenge associated with ammonia combustion is minimizing emissions of nitrogen oxides and nitrous oxides. This project hypothesized that these emissions could be minimized by partially cracking ammonia into a mixture of ammonia, hydrogen, and nitrogen prior to combustion. Other factors were also varied with a primary focus on exploring the sensitivity of the reaction to the Zeta and Lambda scalar dissipation rates. Results indicated that the presence of ammonia in the oxidizer stream aided in the reduction of NO and NO₂ emissions, however, the reduction was accompanied by a slight increase in N₂O emissions. These findings are significant, demonstrating the potential to minimize emissions of reactive nitrogen compounds under specific conditions. Recommendations for future work include investigating peak emissions across varying oxidizer and fuel temperatures, to gain further insight into how ammonia combustion may be optimized.

Bio
Abiani is a junior pursuing a bachelor’s degree in mechanical and aerospace engineering and a minor in computer science. Her research interests include renewable energy and sustainable aviation. She hopes to pursue a career at the intersection of these fields, focusing on innovative solutions for reducing fossil fuel dependence in the aerospace industry.

Arpit Bhardwaj¹

Postdoctoral Research Associate 
Principal Investigator: Ryan Kingsbury^1,2

With Sui Tay³, Kerry Rippy⁴, Bell Robert⁴, Ivy Wu⁴, Irene Walker⁴     

¹ Andlinger Center for Energy and the Environment
² Department of Civil and Environmental Engineering
³ Department of Mechanical and Aerospace Engineering
⁴ National Renewable Energy Laboratory

Analysis of Carbonate Precipitation from Alkaline Mine Waste using First Principles, Multi-element Pourbaix Diagrams

Abstract
CO₂ emissions must be reduced by 18 Gt annually by 2030 to limit global warming to 1.5°C above pre-industrial levels. Alkaline mining waste streams can sequester up to 7.5 Gt of CO₂, with an additional 3.7 Gt possible through producing mineralized products like cement and concrete aggregates. Specifically, reacting CO₂ with Ca- and Mg- containing wastes such as alkaline mine tailings can form target minerals such as dolomite or calcite that can be utilized as concrete aggregates or in cement manufacturing, respectively. Using electrochemistry to mineralize carbonates provides key benefits, including net-zero carbon emissions when powered by clean energy and precise control over precipitation conditions. Pourbaix diagrams (potential-pH plots) are useful tools in this context which indicate the most thermodynamically stable precipitate at specific pH levels, applied potentials, and ion concentrations in the solution. However, existing Pourbaix modeling tools are unable to fully analyze these wastes because of their complex chemistry. We overcome these limitations by carrying out a comprehensive, quantitative analysis of electrochemical mineralization and leverage first-principles DFT calculations to estimate the formation and surface energies of relevant mineral phases and use these results to construct multi-element Pourbaix diagrams for complex alkaline mining wastes.

Bio
Bhardwaj earned a bachelor’s and master’s degree in civil engineering from Indian Institute of Technology (BHU) and a Ph.D. in civil and environmental engineering from Georgia Institute of Technology. His research includes carrying out high throughput Density Functional Theory (DFT) simulations for a variety of applications. These include elastic, electronic and spintronic properties of transition metal dichalcogenide (TMD) nanotubes. Bhardwaj also collaborates with scientists from National Renewable Energy Laboratory (NREL) to study electrochemical mineralization of alkaline mine tailings to form calcite and dolomite. Bhardwaj has published seven research articles in journals such as Nanotechnology. Bhardwaj has been working as a postdoctoral research associate at the Andlinger Center for Energy and Environment since July 2023.

Austin Booth¹

3rd year Ph.D. candidate 
Principal Investigator: Kelsey Hatzell^2,3

¹ Department of Chemical and Biological Engineering
² Andlinger Center for Energy and the Environment
³ Department of Mechanical and Aerospace Engineering

Exploring Competitive Ion Transport Behavior in Ti3C2Tx MXene Membranes

Abstract
Membrane nanofiltration is a growing technology with the potential to enable efficient, selective recovery of high-demand metal ions from wastewater and brine. Most membrane technologies utilize porous materials which are prone to fouling and degradation in highly acidic or basic environments. Using inorganic materials may provide a pathway for separating high value minerals/elements from complex waste streams. Herein, we examine an inorganic membrane comprised of low-dimensional Ti3C2Tx flakes. Ti3C2Tx membranes have rarely been studied in complex ion mixtures, which often yield different ion transport behavior from simple single-salt solutions (especially for 2D-material-based membranes). Herein, we investigated multi-ion transport through MXene membranes by comparing cation permeation in single-salt and mixed solutions of LiCl, NaCl, and CaCl₂. All ion combinations’ permeability and selectivity are significantly reduced in mixed-ion solutions, indicating that competitive transport likely occurs. To further probe the mechanisms behind competitive transport, we applied X-ray diffraction to track the MXene nanoscale structure as a function of the local ionic environment.

Bio
Booth earned a bachelor’s degree in chemical engineering from the University of Notre Dame in 2022. His research interests include membrane separations for energy and environmental applications, as well as designing materials to reduce the energy intensity of carbon capture. Booth hopes his research will help reduce the impact of chemical separations on the environment, improve energy efficiency, and reduce CO₂ emissions. Booth also collaborates with researchers at Argonne National Lab and Northwestern University. He has published in Environmental Science and Technology Letters as a co-author, and he is currently working on a first-author publication. Booth will conduct research at Argonne National Lab in summer 2025 as part of the DOE Office of Science Graduate Student Research (SCGSR) program. After graduation, he hopes to pursue a career at the U.S. National Laboratories or in industry.

Blake Brown¹

Undergraduate Class of 2027
Principal Investigator: Claire Gmachl¹

With Emmanuel Ishola², Manuel Gallego¹

¹ Department of Electrical and Computer Engineering
² Department of Mechanical and Aerospace Engineering

Investigating Emissivity of Stealthy-Hyperuniform Materials Using Mid-IR Thermography and Power Measurements

Abstract
Understanding the emissivity of materials is crucial for various applications in thermal science and engineering. Emissivity is defined as the ratio of the energy emitted by a material to that emitted by a perfect blackbody at the same temperature. It plays a pivotal role in determining the accuracy of temperature measurements using infrared (IR) thermography, where emissivity affects the thermal radiation emitted and detected by the IR camera. By measuring the impact and change in emissivity across Stealthy-Hyperuniform structures, it not only reveals critical information about the materials quasi-makeup, but also provides insight into how these materials react under IR stimulation such as heat and light for its potential use in more delicate and IR-based technology.

Bio
Brown is a sophomore pursuing a bachelor’s degree in electrical and computer engineering, with a minor in computer science and a certificate in robotics and AI technology. His research interests lie at the intersection of hardware and software, where he seeks to integrate both in innovative ways. Brown continues to collaborate with researchers in Princeton’s Department of Physics and Department of Electrical and Computer Engineering to supplement his knowledge and hands-on experience. On campus, he is an active member of the Princeton University Robotics Team, the National Society of Black Engineers (NSBE), HackPrinceton, and other STEM-focused organizations. He aspires towards a career in robotics technology, with a particular focus on leveraging machine learning to optimize the interaction between robotic systems and physical environments.

Anherutowa Calvo¹

Undergraduate Class of 2027
Principal Investigator: Jonathan Conway¹

With Hansen Tjo¹

¹ Department of Chemical and Biological Engineering

Engineering Extremely Thermophilic Cellulolytic Organisms and Enzymes for Biofuel Production

Abstract
Caldicellulosiruptor bescii, an extremely thermophilic anaerobe, is studied for its potential in biomass saccharification due to its ability to degrade lignocellulose without pretreatment. Genetic modifications, including targeted deletions of specific sugar transport proteins, have provided insights into carbohydrate uptake mechanisms, focusing on the transport of diverse sugars across the cell membrane. Enzymes from C. bescii and related thermophiles have been evaluated for their roles in breaking down complex carbohydrates into fermentable sugars. This research enhances the understanding of sugar transport and enzymatic breakdown, contributing to the development of strains optimized for converting biomass into biofuels and other valuable biochemicals. These findings support the metabolic engineering of C. bescii for applications in sustainable bioenergy production.

Bio
Calvo is a sophomore pursuing a degree in chemical and biological engineering. He leads the Bionics Project in Princeton Robotics, where they are developing a myoelectric prosthetic hand to improve the lives of individuals with limb differences, and is also a machine learning enthusiast, working on AI models for breast cancer detection. As an EcoRep Leader, Calvo is committed to solving global environmental challenges and has gained insight into non-model bacteria and their role in sustainability. In Professor Jonathan Conway’s lab, he researches thermophilic microbes for biofuel production, aspiring to pursue a career at the intersection of machine learning, biotechnology, and pharmaceutical research to make medical treatments more accessible and equitable for all.

Eric Chen¹

Undergraduate Class of 2025 
Principal Investigator: Minjie Chen^1,2

With Glaucio Paulino³, Yifan Rao², Tuo Zhao³, Konstantinos Manos¹, Calvin Nyguen¹

¹ Department of Electrical and Computer Engineering
² Andlinger Center for Energy and the Environment
³ Department of Civil and Environmental Engineering

Designing and Building a Large-scale Helmholtz Coil to Manipulate Complex Origami Robot Structures with Improved Control Granularity and Range of Motion

Abstract
Most robotics systems currently in use rely on either an internal battery that is intermittently charged, or direct charging to provide power to local systems. As robots become smaller and approach micrometer or nanometer scales, sustaining battery technology to fit these size constraints become increasingly challenging. Paulino’s laboratory is currently working on magnetic origami robots which give two major benefits. By integrating permanent magnetics within origami structures, magnetic fields can be used to extend or contract these robots and achieve both control and power transmission wirelessly.  My research revolves around constructing a 3-dimensional Helmholtz coil project that can manipulate magnetic objects such as foldable origami robots without direct contact. The current design is limited in space and ease of use. The project consisted of designing and building an improved coil system to test larger, more complex structures and improve the granularity of control by isolating certain origami robots for movement while others remain set or moving the entire structure as one object.

Bio
Chen is a senior pursuing a bachelor’s degree in electrical and computer engineering, and a certificate in robotics and intelligent systems. His research interests include mechanical designs of robots, efficient power electronics, and wireless power transfer and communications. Chen currently collaborates with researchers in the Department of Electrical and Computer Engineering, the Andlinger Center for Energy and the Environment, and the Department of Civil and Environmental engineering. He hopes to apply these interests to pursue a career in applying robotics to various fields such as agriculture, construction, and medicine. 

Abigail Cheng¹

Undergraduate Class of 2027
Principal Investigator: Jesse Jenkins^2,3

With Qian Luo²

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment
³ Department of Mechanical and Aerospace Engineering

Estimate Impacts of EPA Greenhouse Gas Standards for Power Plants on Retail Electricity Prices

Abstract
In April 2024, the EPA announced regulations to address greenhouse gas emissions from fossil fuel-fired electric generating units. These rules will impact retail electricity prices due to mandated retrofits with low-emission technologies and a shift towards natural gas and renewables. By 2040, estimates suggest that a New Rules scenario will increase prices by an average of 0.33% versus a Benchmark scenario. Variation in this price difference happens due to the range of electricity market structures across all U.S. regions.

Bio
Cheng is a sophomore pursuing a bachelor’s degree in the civil and environmental engineering department with a concentration on energy and policy and a minor in the Program in Sustainable Energy.  Her research interests include developing models for the power sector to inform future policy. At Princeton, Cheng is an Officer in the Princeton University Energy Association and does a cappella. She hopes to pursue a career in policy to make decisions about where and how to focus efforts to maintain a clean, reliable, cost-effective, and equitable power system.

Aaron Dantzler¹

Undergraduate Class of 2025
Principal Investigator: Ronnie Sircar¹

¹ Department of Operations Research and Financial Engineering

Operational Risk Financialization of Electricity Under Stochasticity

Abstract
Our research focused on the integration of batteries into the electric power grid. We first focused on the current simple strategies that batteries use to bid for wholesale electricity and ancillary services in the Texas ERCOT power grid, mainly bidding in hours where load consumption was forecasted to be the highest and focusing on ancillary services. We then projected the revenues of these batteries and implemented strategies that batteries could use to take advantage of energy pricing arbitrage. These strategies will encourage increased battery penetration and lessen the strain on the grid during peak hours.

Bio
Dantzler is a senior pursuing a bachelor’s degree in operations research and financial engineering and certificates in computer science and cello performance.  His research interests include optimization of the power grid and machine learning for diabetes management. Dantzler is a member of the Princeton University Orchestra, La Vie En Cello and Opus Chamber Music. He hopes to pursue a career in energy, particularly optimization and decarbonization of the power grid.

Claire DeGuzman¹

Undergraduate Class of 2027
Principal Investigator: Jose Avalos¹

¹ Department of Chemical and Biological Engineering

Microbial Engineering for Energy and the Environment

Abstract
The goal of this project was to optimize the purification process of the Erg20 enzyme as well as a condensing form of the enzyme which is attached to the intrinsically-disordered protein Laf1. ERG20 enzyme purification can be optimized through one wash through a metal-affinity column followed by two runs through a size-exclusion column. The Laf1 fused with Erg20 can be purified through a series of salt washes and centrifuge steps. When Laf1-Erg20 fusion is washed and spun in 0.5M NaCl followed by 1M NaCl, the protein appears in the second supernatant with relatively high purity.

Bio
DeGuzman is a sophomore pursuing a bachelor’s degree in chemical and biological engineering with a concentration in bioengineering and biotechnology. Her research interests include developing sustainable energy systems and technologies. She hopes to pursue a career in the energy industry where she hopes to bring large-scale clean energy technologies to the market.

Austin Fan¹

3rd year Ph.D. candidate
Principal Investigator: Kelsey Hatzell^2,3

With Zhuo Li²

¹ Department of Chemical and Biological Engineering
² Andlinger Center for Energy and the Environment
³ Department of Mechanical and Aerospace Engineering

Visualization of Lithium Growth in Zero-Excess-Lithium Solid-State Batteries Enabled by a Novel Optical Microscopy Cell

Abstract
Growing demands for electric vehicles motivate the need for energy-dense battery technologies that can enable enhanced driving ranges on a single charge. Zero-excess-lithium solid-state batteries operate with no excess lithium at the anode, instead fully cycling all the lithium within the cell during each cycle. Removing excess lithium significantly increases the specific and volumetric energy density, improves battery safety, and reduces manufacturing costs.  However, zero-excess-lithium solid-state batteries suffer from poor coulombic efficiency and lithium dendrite formation resulting from non-uniform lithium deposition onto the anodic current collector. In this work, we investigate the lithium nucleation and growth behavior on a current collector substrate using a custom cell conducive to operando optical microscopy. In particular, quantifying the dynamic in-plane lithium growth as a function of operating conditions such as current density, temperature, and thermal gradients provides crucial insight into the lithium growth mechanism. These results enable comprehensive characterization of lithium growth regimes, including in-plane-growth dominant and vertical-growth dominant regimes, at successive capacities of lithium plated. Understanding these lithium growth regimes guides strategies to attain more lateral, uniform lithium deposition, with long-term implications in achieving stable, high-capacity zero-excess-lithium solid-state battery operation.

Bio
Fan earned his bachelor’s degree in chemical and biomolecular engineering from Georgia Institute of Technology. His research interests include understanding the lithium deposition process in solid-state batteries to improve their performance as an important sustainable energy technology. He has recently presented his work at ECS PRiME and hopes to continue researching solid-state battery technology for the remainder of his Ph.D. candidacy and beyond.

Luc Harbers¹

Undergraduate Class of 2025
Principal Investigator: Egemen Kolemen^1,2,3

With Yufan Xu², Brian Wynne¹

¹ Department of Mechanical and Aerospace Engineering
² Princeton Plasma Physics Laboratory
³ Andlinger Center for Energy and the Environment

Laser Profiling for Liquid Metal Fast Channel Flow Surface Wave Diagnostics

Abstract
Liquid-metal plasma facing components show greater efficacy for managing the high heat flux and radiative damage present in a tokamak in comparison to their solid counterparts. However, surface waves in the flow can degrade performance. Existing methods for measuring surface waves lack resolution and consistency. Experiments on the Liquid Metal eXperiment Upgrade investigated surface wave formation in a flow of Galinstan. Novel diagnostics for surface waves using a Keyence LJ-8080X laser profiler are demonstrated. A mount was designed to facilitate replicable diagnostics. Surface wave measurements are taken at various interaction parameters, processed with spectral analysis, and compared to high-speed camera observations.

Bio
Harbers is a senior pursuing a bachelor’s degree in mechanical and aerospace engineering. He is interested in fusion technology, with a focus on applications of liquid metals. He is a member of the Princeton University Lightweight Rowing Team, where he serves as a coxswain. Harbers hopes to work in the energy industry, specifically in oil and gas.

Shu Hayashi¹

Postdoctoral Research Associate
Principal Investigator: Craig B. Arnold²

With Marco Rupp², Jason X. Liu³, Joseph W. Stiles⁴, Ankit Das², Amelia Sanchirico², Samuel Moore³

¹ Princeton Materials Institute
² Department of Mechanical and Aerospace Engineering
³ Department of Chemical and Biological Engineering
⁴ Department of Chemistry

Laser Upcycling of Hemoglobin Protein Biowaste into Engineered Graphene Aerogel Architectures for 3D Energy Storage Applications

Abstract
Graphene aerogels (GAs) with engineered architectures are a promising material for applications such as energy storage/conversion. However, current preparation approaches involve the combination of multiple intrinsically different methodologies to achieve graphene-synthesis and architecture-engineering, complicating the entire procedure. Here, we demonstrate the direct preparation of architecture-engineered GAs through the laser-upcycling of hemoglobin protein sourced from animal blood biowaste. Laser scanning achieves graphene-synthesis concurrently with architecture-engineering through the localized graphitization of a bed of freeze-dried hemoglobin powder along the laser-scan path. By leveraging the high electrical-conductivity and unique structural-morphology, the laser-upcycled GAs are applied as electrodes of symmetrical 3D-supercapacitors. The fabricated supercapacitors exhibited exceptional performance despite the large electrode-thickness, attributable to the laser-engineered architecture facilitating ion diffusion.

Bio
Shu earned his bachelor’s, master’s, and doctorate degrees in electronics and electrical engineering from Keio University, Japan. His research interest includes laser materials processing, with particular emphasis on light-induced structural evolutions and 2D/3D-patterning of functional materials for electrical and optical applications. He hopes his research will aid in developing new techniques to upgrade low-value materials as sustainable alternatives for current material options. Shu actively collaborates with researchers in the Department of Chemical and Biological Engineering and the Department of Chemistry. Shu has published in various journals, including Nano Letters, Optics & Laser Technology, and Optical Materials Express. After his postdoctoral journey, Shu hopes to continue his academic career by joining a university as a faculty member.

Ashley Holmes¹

Undergraduate Class of 2026 
Principal Investigator: Rania Bashar²

¹ Department of Civil and Environmental Engineering
² Moonshot Missions

Investigation into Climate-related Vulnerabilities and Potential Solutions in Oconto, Wisconsin Wastewater Facilities

Abstract
The Great Lakes region is vulnerable to the climate risks associated with extreme weather events like flooding and storms. This presents a challenge to the infrastructure in the area. Water and wastewater utilities will have to deal with both maintenance costs for repairing damage after extreme weather events as well as adaptation costs like building sea walls. Oconto, Wisconsin was used as a case study for this topic. Overall, the Oconto Wastewater Facility’s main climate related issues are that they are at risk of flooding, and they need a source of reliable backup energy for lift stations. Also, the city is looking to implement major capital upgrade projects to replace aging infrastructure for which they are looking to incorporate climate considerations to ensure long-term sustainability.

Bio
Holmes is a junior pursuing a bachelor’s degree in civil and environmental engineering. Her research interests lie in water quality and biological wastewater treatment. Holmes is also involved in Engineers without Borders and Outdoor Action on campus. She hopes to pursue a career in water resources and waste management. 

Jisu Hong¹

Postdoctoral Research Associate
Principal Investigator: Barry P. Rand^1,2

With Zhaojian Xu¹,Tuo Hu¹, Sujin Lee¹, Antoine Kahn¹

¹ Department of Electrical and Computer Engineering
² Andlinger Center for Energy and the Environment

Evaporated Organic-MoO₃ Composite Hole Transport Layers toward Stable Perovskite Solar Cells

Abstract
The release and diffusion of corrosive iodine species limits the stable operation of perovskite solar cells (PSCs). In this study, molybdenum trioxide (MoO3) is employed for efficient oxidation (p-doping) of organic hole transport layers (HTLs), replacing the conventional dopant lithium bis(trifluoromethane)sulfonimide (LiTFSI) which compromises stability. Co-deposition of 2,2′,7,7′-tetra(N,N-di-p-tolyl)amino-9,9-spirobifluorene (spiro-TTB) and MoO3 via thermal evaporation produces an HTL with appropriate ionization energy, electrical conductivity, and homogeneous morphology. To investigate the stability of PSCs using the composite HTL, three types of PSCs with different HTLs are fabricated; the 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD) control HTL with conventional dopants, the spiro-TTB:MoO3 composite HTL, and the double HTL with doped spiro-OMeTAD and spiro-TTB:MoO3 layers. The most efficient PSC with a power conversion efficiency of 21.3% is achieved by the double HTL. Since the efficient oxidation of spiro-TTB by MoO3 and stable morphology under thermal stress mitigate iodine diffusion through the spiro-TTB:MoO3 HTL, the PSC employing the composite HTL demonstrates superior thermal stability, retaining 81% of the initial efficiency after 200 h aging at 85 °C.

Bio
Hong is a postdoctoral research associate in the Department of Electrical & Computer Engineering. Her research focuses on halide perovskite solar cells, particularly in understanding device degradation mechanisms and developing charge carrier transport layers that mitigate the diffusion of corrosive species and enhance charge carrier transport to the electrodes for efficient and stable solar cells. She earned her Ph.D. in chemical engineering from Pohang University of Science and Technology (POSTECH) in South Korea, followed by postdoctoral research at POSTECH, before joining Princeton for interdisciplinary work. She aims to pursue a career in academia, advancing research in sustainable energy and electronics.

Vishva Ilavelan¹

Undergraduate Class of 2026
Principal Investigator: Z. Jason Ren^2,3

With Junjie Zhu²

¹ Department of Computer Science
² Department of Civil and Environmental Engineering
³ Andlinger Center for Energy and the Environment

Large Language Model Applications for Environment, Sustainability, and Energy

Abstract
The creation of artificial intelligence tools to answer questions about specific environmental engineering topics can be challenging, necessitating large datasets. However, LLMs (Large Language Models) act as a natural groundwork for developing environmental AI tools. Open-source LLMs created by companies like Meta have been trained for understanding human language and are thus highly versatile. In turn, fine-tuning such models using environmental training materials acts as an accessible pathway for creating environmental engineering AI tools. This project pursues this methodology, fine-tuning some base LLMs and presenting some accuracy metrics for environmental question answering tasks.

Bio
Ilavelan is a junior concentrating in computer science with a minor in statistics and machine learning. His primary research interests include machine learning, particularly the subfields of computer vision and natural language processing. He is highly interested in generative artificial intelligence, particularly LLMs and their applications in different academic domains. Ilavelan also enjoys developing full-stack applications and has experience with various front and backend frameworks and libraries, including Flask, JQuery, Express.js, and React.js. He hopes to pursue a career in machine learning and software engineering.

Hui Taou Kok¹

2nd year Ph.D. candidate
Principal Investigator: Barry Rand^2,3

With Chiao-Jung Su³

¹ Department of Physics
² Andlinger Center for Energy and the Environment
³ Department of Electrical and Computer Engineering

Crystallization and Epitaxy in Chiral Molecular Systems

Abstract
The integration of organic semiconductors in display technology offers innovative alternatives to traditional inorganic, primarily silicon-based, semiconductors. These materials provide new applications scopes and are particularly promising for diffuse lighting and thin, light, curved, and/or flexible displays. Unlike inorganic systems, which rely on strong covalent bonds and are constrained by lattice matching due to their atomic structure, organic systems interact through much weaker van der Waals forces, potentially allowing them to accommodate more significant lattice mismatch but still allow for coherent crystalline growth. However, previous research suggests that the lattice-matched crystal face must also be the lowest surface energy face for successful epitaxy, complicating interpretation. To better resolve the influence of crystal lattice mismatch on growth, we are investigating stereoisomers of the same molecule, specifically R- and S-BINAP; the pure enantiomers of these molecules have unique crystal structures in comparison to their racemic mixture, but surface energies are similar. This approach aims to enhance understanding of epitaxial growth in organic semiconductors and support their technological applications.

Bio
Kok earned a bachelor’s and master’s degree in physical natural sciences from the University of Cambridge, UK. Her research interests focus on organic semiconductors, aiming to provide innovative alternatives to traditional silicon-based semiconductors. Kok’s research is centered on identifying factors that influence homo and hetero epitaxy in molecular systems, with a specific interest in using chiral molecules to enhance understanding of epitaxial growth. She hopes her research will contribute to the fundamental aspects governing the success of epitaxy in molecular systems. Looking (very far) ahead, Kok plans to expand her research into entrepreneurial ventures. She aims to continue bridging interdisciplinary fields to foster technological innovations.

Michael Lau¹

3rd Year Ph.D. candidate
Principal Investigator: Jesse Jenkins^1,2

¹ Department of Mechanical and Aerospace Engineering
² Andlinger Center for Energy and the Environment

Modelling to Generate Continuous Alternatives

Abstract
Decarbonization and its shift towards highly-renewable energy systems is creating a new opportunity to incorporate public preferences in energy system planning. The transition provides new opportunities to plan energy systems for improved health, resilience, equity, and environmental outcomes, but challenges in siting and social acceptance of transition goals and targets threaten progress. Modelling to Generate Alternatives (MGA) provides an optimization method for capturing many near-cost-optimal system configurations, and thus can provide insights into the tradeoffs between objectives and flexibility available in the system. However, MGA is currently limited in interactive applicability to these problems due to a lack of methods for allowing users to explore near-optimal feasible spaces. In this paper, we introduce a novel MGA post-processing algorithm, Modelling to Generate Continuous Alternatives (MGCA). MGCA provides the ability to explore the interior of the near-optimal feasible set, including metric values, extremely rapidly using all the tools of linear programming by introducing an exploratory optimization problem on a reduced dimension subspace of the original capacity expansion model. We demonstrate that this problem can be leveraged to explore the discovered near-optimal feasible space with other optimization tools, including multi-objective optimization and the imposition of new constraints. Finally, we demonstrate that these interpolates can be exported to a full capacity expansion model to evaluate their operational outcomes with least-cost dispatch. All MGCA capabilities can be implemented on personal computers and evaluated in fractions of a second, making them perfectly suited for live, interactive applications including decision support, negotiations, siting discussions, community engagement, and preference gathering.

Bio
Lau is a Ph.D. candidate in mechanical and aerospace engineering at Princeton University and a researcher in the ZERO Lab, where he focuses on methods to explore the near-optimal feasible region of energy systems planning problems and provide decision support on trade-offs and options in the transition to net-zero emissions. He is also an HMEI-STEP Graduate Fellow in science, technology and environmental policy.

Peteris Lazovskis¹

2nd year Ph.D. candidate 
Principal Investigator: Forrest Meggers^1,2

With Ariane Adcroft³

¹ School of Architecture
² Andlinger Center for Energy and the Environment
³ Department of Mechanical and Aerospace Engineering

Extracting Thermal Mass Sizing Parameters from an Existing Trombe Wall System

Abstract
Trombe wall systems use south-facing structural mass to store heat and cool in a way that can reduce a building’s operational energy consumption through radiant and convective energy transfer. However, such systems are rarely implemented in buildings due to a lack of easily accessible design guidance and a lack of empirical performance studies of full-scale systems. Here, we perform an empirical study of an existing, full-scale, Trombe wall system over five months by gathering ambient and radiant surface temperature, as well as solar irradiance and convective airflow data. Using these, we develop a parametric model for correlating the dimensions of the structural wall with its capacity to exchange energy with the building interior and exterior.

Bio
Lazovskis earned a bachelor’s degree in architecture from Carleton University (Canada) and a master’s degree in architecture from the Harvard University Graduate School of Design. His research interests include developing novel techniques for integrating low-energy climate-control systems into building facades. Lazovskis has practiced architecture professionally for over five years and holds a patent for a building dehumidification device. He hopes to continue his career in professional architecture or in building façade technology.

Christina Li¹

Undergraduate Class of 2026 
Principal Investigator: Doug Roe²

¹ Department of Operations Research and Financial Engineering
² Federal Energy Regulatory Commission

Deriving Locational Value from Distributed Energy Resources in Compliance with FERC Order No. 2222: A Comparison of NYISO, PJM, and ISO-NE

Abstract
This paper analyzes how NYISO, PJM, and ISO-NE are complying with FERC Order No. 2222, which aims to integrate Distributed Energy Resources (DERs) into wholesale markets. It compares their approaches to locational value and technical requirements, highlighting the trade-offs between aggregation broadness versus operational and cost-reflective feasibility, and granular metering versus cost barriers. The study finds that while all three organizations have made strides, challenges remain, particularly in balancing the integration of smaller DERs with the need for precise metering and aggregation strategies. The findings underscore the importance of modern metering infrastructure and cost-reflective pricing in unlocking DER locational value.

Bio
Li is a junior pursuing a bachelor’s degree in operations research and financial engineering with minors in art history and French language and culture. Her research interests include energy markets, energy systems engineering, and optimization. Li is interested in the sociotechnical problems at the heart of the clean energy transition. At Princeton, Li is a member of the Women’s Openweight Rowing team and plays the cello. Li is undecided about her future plans but hopes to continue exploring the intersection of energy and other fields.

Summer Li¹

2nd year Ph.D. candidate
Principal Investigator: Z. Jason Ren^1,2

With Cuihong Song¹  

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment

The Impact of the Clean Grid Transition on the Greenhouse Gas Emissions of Water Resource Recovery Facilities

Abstract
Wastewater treatment is an essential part of modern infrastructure, safeguarding public health and protecting the environment. However, it is also an energy-intensive process. This study examines the spatial and temporal impacts of the U.S. clean energy grid transition on the related greenhouse gas (GHG) emissions from wastewater resource recovery facilities (WRRFs). By analyzing data from 17,156 WRRFs and state-specific grid decarbonization scenarios, the results project a 62.82% reduction in Scope 2 emissions by 2050, driven by the national shift to renewable energy. However, regional disparities are prominent, with Northeastern and Western states achieving the most significant reductions, while the Ohio Valley and Rockies are likely to experience higher emissions due to reliance on fossil fuels. This study offers the first assessment of clean grid impacts on the WRRFs, and highlights the need for targeted, region-specific strategies across different emission scopes. This research provides insights for policymakers and stakeholders in the wastewater sector, emphasizing the critical role of grid decarbonization in achieving GHG reduction goals.

Bio
Li earned her bachelor’s degree in civil and environmental engineering from Zhejiang University and her master’s degree in civil and environmental engineering from Stanford University. Her research encompasses climate change, focusing on modeling renewable energy recovery and sustainable development within the water and wastewater industries. Through her work, Li aims to inform the development of meaningful stakeholder engagement strategies, ultimately enhancing decision-making processes in energy and water resource assessments.

Zixi Li¹

3rd year Ph.D. candidate 
Principal Investigator: David Wentzlaff¹

¹ Department of Electric and Computer Engineering

LUCIE: A Universal Chiplet-Interposer Design Framework for Plug-and-Play Integration

Abstract
Multi-chip modules, recently also known as chiplets, are a promising approach to building large-scale silicon in the post-Moore’s Law era. While chiplet-based designs offer advantages like averting manufacturing yield issues and enabling heterogeneous integration, there has not been a standard for seamless communication and integration of chiplets. This paper proposes LUCIE, a Lightweight Universal Chiplet-Interposer Ecosystem that provides a universal, modular, and reconfigurable framework for plug-and-play integration of chiplets. The key ideas behind LUCIE include a flexible 2D grid-based interposer design and a placement tool to aid chiplet integration. Its lightweight design and direct connection between chiplets allowed designs to fit into the LUCIE framework with minimal effort while achieving great performance. Performance analysis showed that LUCIE’s performance is comparable to custom interposers, up to twice as fast as NoC-on-NoP designs in certain scenarios, and around 20% more power efficient than NoC-on-NoP designs. Compared to using custom interposers, cost analysis showed that LUCIE saves up to 18.9% of manufacturing cost, $60,000 of Non-Recurring Engineering cost, and 30 weeks less time-to-market. The LUCIE framework is more flexible and ideal for more topologies, such as 2D mesh and star topology. With the development of a novel, graph-based placement algorithm, LUCIE significantly reduces design complexity compared to monolithic and custom interposer-based chiplet systems while providing a high degree of modularity and reconfigurability.

Bio
Li is a third-year graduate student pursuing a Ph.D. in electrical and computer engineering. He earned a bachelor’s degree in computer engineering at the University of Illinois Urbana-Champaign. Li is interested in research on chiplets, including computer architecture for chiplets, advanced packaging techniques, demystifying and simplifying ASIC design with chiplets, reusability of chiplet systems, and sustainability and cost analysis of chiplet ecosystems. Li hopes his research can lower the barrier of entry into the chiplet manufacturing landscape and promote a sustainable, efficient circular economy with chiplet mass chiplet reconfiguration and reusing.

Nusrat Molla¹

Distinguished Postdoctoral Fellow
Principal Investigator: Elke Weber^1,3,4, Simon Levin²

With Savannah Reese¹

¹ Andlinger Center for Energy and the Environment
² Department of Ecology and Evolutionary Biology
³ Department of Psychology
⁴ School of Public and International Affairs

Beyond Extraction: Modeling and Narratives for Post-Extractive Futures in Appalachia

Abstract
Sustainability transitions such as the energy transition will inevitably reshape rural communities long dominated by extractive industries. A history of underinvestment and weak institutions have left these communities the least prepared to adapt to social and economic change. This study explores the challenges of overcoming entrenched dynamics of extractive industries in Central Appalachia’s coal mining communities using a combination of systems modeling and interviews and participant observation. The qualitative findings highlight divergent visions for Appalachia’s future, ranging from transitions fueled by external investments to transformative approaches emphasizing regional economies based on local autonomy and collective ownership of natural resources. Additionally, a growing movement seeks to reframe Appalachian values and history as compatible with a green economy. Systems modeling is employed to examine these varying future visions and the pathways to achieve them, considering the impact of extractive legacies on the region’s institutions, infrastructure, and natural resources. This study aims to provide insights into how entrenched power structures influence transition pathways while exploring fundamentally different futures for the region.

Bio
Molla earned a Ph.D. in hydrologic sciences, with a focus on water policy and management, from UC Davis. Her work focuses on combining complexity science and qualitative methods to understand mechanisms of sustainability transformations in regions impacted by extractive industries.

Malini Nambiar¹

6th year Ph.D. candidate
Principal Investigator: Denise Mauzerall^1,2

With Jesse D. Jenkins^3,4, Rahul Tongia⁵, Aneesha Manocha⁶

¹ School of Public and International Affairs
² Department of Civil and Environmental Engineering
³ Andlinger Center for Energy and the Environment
⁴ Department of Mechanical and Aerospace Engineering
⁵ Center for Social and Economic Progress, Delhi, India
⁶ Energy Resources Group, University of California Berkeley

The Value of Flexible Coal in a Decarbonizing Indian Grid

Abstract
India has adopted ambitious clean energy targets that are expected to be met in large part by deployment of variable renewable energy resources (VREs). However, greater system flexibility than currently exists in India is required to integrate VRE capacities at the pace and scale anticipated. Here we comprehensively study the long-term and system-wide value of retrofitting coal units for enhanced operational flexibility and assess optimal strategies for deploying flexible coal, VRE, and energy storage. We show that flexible coal retrofits offer modest cost and emissions benefits and are most valuable in cases with high solar-to-wind deployment ratios. Contrary to current government policy mandating retrofits for the entire coal fleet, system-wide cost reductions are maximized when only a subset of younger subcritical units take up flexibility enhancements.

Bio
Nambiar earned a bachelor’s degree in earth and environmental engineering from Columbia University. Her Ph.D. research interests include considerations for emerging economies like India for electricity decarbonization strategies, electricity markets and regulation, and balancing competing stakeholder priorities. She also collaborates with researchers in the Andlinger Center for Energy and Environment on the Net-Zero India project. Prior to Princeton, Nambiar was a senior consultant at Ramboll, where she managed technical assistance projects related to air pollution modeling and GHG accounting/mitigation. After her Ph.D., Nambiar plans to pursue a career in domestic decarbonization policymaking at state or federal agencies.

Ouriel Ndalamba¹

2nd year Ph.D. candidate
Principal Investigator: Ryan Kingsbury^{1, 2}

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment

Advancing Resource Recovery by Understanding Salt Partitioning into Ion Exchange Membranes

Abstract
Ion exchange membranes (IEMs) are filtration materials that enable a variety of water and wastewater treatment applications, including water desalination and resource recovery from waste. These applications typically involve complex mixtures (such as seawater and industrial wastewater) characterized by the presence of multiple salts. However, membrane properties are usually measured in single salts solutions. The complex mixtures of interest for IEM application have been shown to reduce the selectivity of membranes in ways that are difficult to predict based only on single salt performance measurements. Therefore, we seek to identify the fundamental principles by which IEMs separate ions from a complex mixture by evaluating the partition coefficient. In this work we investigate how the partition coefficient varies with changing the composition of salt solutions for two cation exchange membranes.

Bio
Ndalamba earned a bachelor’s degree in chemical engineering from the University of Maryland, Baltimore County. Her research interests include understanding fundamental principles of ion exchange membranes for applications in water treatment and resource recovery. Ndalamba hopes that the outcome of her research will contribute to the development of more efficient membrane separation processes. Ndalamba will take her general examination in Spring 2025 after which she will work toward completing her Ph.D. dissertation.

Calvin Nguyen¹

Undergraduate Class of 2025
Principal Investigator: Minjie Chen^1,2

With Konstantinos Manos¹

¹ Department of Electrical and Computer Engineering
² Andlinger Center for Energy and the Environment

Magnetic Actuation of Objects aided by Computer Vision

Abstract
We demonstrate a novel method for precise magnetic manipulation using three pairs of Helmholtz coils arranged along the X, Y, and Z axes to generate a customizable magnetic field. By employing this rotating magnetic field, we can induce torque on a magnetically responsive cube, enabling controlled movement within a defined space. The cube’s position is tracked using ArUco markers placed on both the object and the maze environment. This setup allows for accurate navigation and positioning of the cube to a target location.

Bio
Nguyen is a senior pursuing a bachelor’s degree in electrical and computer engineering and a minor in statistics and machine learning. His research interests include developing novel methods of actuation in robotics. Nguyen collaborates with researchers in the Power Electronics Laboratory in these endeavors. Nguyen is also a part of the Princeton Electric Speedboating team, dedicated to making high-performance electric boats. He hopes to pursue a master’s in electrical engineering.

Chirayu Nimonkar¹

Undergraduate Class of 2026
Principal Investigator: Chris Greig²

With Dominic Davis²

¹ Department of Computer Science
² Andlinger Center for Energy and the Environment

Adaptive Scheduling and Optimization of Net-Zero Infrastructure Deployment Pathways

Abstract
The goal of this project is to better model and schedule the individual projects needed to help the United States reach net-zero carbon emissions by 2050. We modeled representative net-zero asset types using domain knowledge and data to inform modeling assumptions. We then scheduled these assets using mixed integer linear programming optimization. With this approach, we can simulate interventions in the plan. Finally, we plan to adaptively improve the calculated plans using learned data. The end-goal is to use scheduling as an ongoing process that aids in the deployment strategy over a long-term horizon instead of a one-time task.

Bio
Nimonkar is a junior pursuing a bachelor’s degree in computer science and certificates in applied and computational mathematics and statistics and machine learning. His research interests include unsupervised reinforcement learning, computer vision, and computational cognitive science. Nimonkar also collaborates with researchers in the Department of Computer Science and the Computational Cognitive Lab. Nimonkar has published a paper in an IEEE journal on novel brain phantoms and holds a patent in the manufacturing process and is currently working on two machine learning papers.

August Ning¹

5th year Ph.D. candidate
Principal Investigator: David Wentzlaff¹

¹ Department of Electrical and Computer Engineering

Carbon Characterization of a Megawatt-scale Research Data Center

Abstract
Sustainability has become an emerging design metric for computer systems and chip designers as companies and institutions aim to reduce their environmental impact. In existing work from industry data centers, this may involve optimizing job scheduling and server design to reduce operational and embodied carbon emissions respectively. However, large cloud providers and their users have different constraints, motives, and incentives compared to research data centers. In this work, we characterize Princeton’s High Performance Computing Research Center (HPCRC), a 5 Megawatt heterogenous research cluster with multiple systems used by Princeton researchers. Combining data from over 175 million core-hours of computer workloads, hourly solar/grid energy consumption rates, and carbon estimate models, we present a fine-grained analysis of HPCRC’s operational and embodied carbon emissions. From our characterization, we propose optimizations spanning the software/hardware stack for reducing emissions, as well as evaluating potential performance and cost trade-offs.

Bio
Ning earned a bachelor’s degree in electrical and computer engineering from Duke University and a master’s degree from Princeton University. His research interests span computer architecture under broad economic constraints such as semiconductor manufacturing supply chains, trade policies, cost-aware large language model inference, and sustainability. He has published in top computer architecture and circuits conferences including ISCA, HPCA, and CICC. He is in the job market for industry research and academic postdocs.

Daniel Paluku¹

2nd year Ph.D. candidate 
Principal Investigator: Craig Arnold¹

With M. Shaharyar Wani¹, Joseph W. Stiles², Maha Yusuf³, Jonah Erlebacher⁴ 

¹ Department of Mechanical and Aerospace Engineering
² National Renewable Energy Laboratory
³ Andlinger Center for Energy and the Environment
⁴ Department of Materials Science and Engineering, John Hopkins University

Low Energy Synthetic Graphite from Natural Gas as Anode Material for Li-ion Batteries

Abstract
Synthetic graphite is the industry standard anode material in lithium-ion batteries (LIBs). It offers several advantages such as long battery cycle life and high theoretical capacity. However, the production of synthetic graphite is energy-intensive, resulting in increased greenhouse gas emissions and carbon footprint. Therefore, alternative low-energy carbon synthetic routes to graphite manufacturing are crucial to minimize the carbon footprint of battery making.  In this work, we present electrochemical viability of synthetic graphite (SG) obtained by the removal of metal from metal-carbon composites synthesized from the reduction of natural gas with metal chloride.  We evaluate the electrochemical behavior of SG under a range of cycling rates (C/10, C/2, 1C, 2C, 10C), and compare its behavior with that of a wide range of commercial synthetic graphite materials. Our results demonstrate the viability of SG as an alternative low energy-intensive carbon anode material for LIBs showing favorable performance as compared to commercial synthetic graphite produced through high energy methods.

Bio
Paluku earned a bachelor’s degree in mechanical and energy engineering from Kazan State Power Engineering University in Russia. Before joining Princeton, Paluku spent a year at the University of Erlangen-Nuremberg in Germany, where he expanded his knowledge in materials science for energy applications through their master’s program in clean energy processes. His current research focuses on novel materials, such as graphite and aerogels, for battery technology. Paluku hopes his research will contribute to the use of environmentally friendly materials in lithium-ion batteries. His work involves collaboration with researchers in the materials science and engineering department at Johns Hopkins University. Paluku is currently preparing his first first-author publication since joining Princeton University.

Jaeboem Park¹

2nd year Ph.D. candidate
Principal Investigator: Ryan Kingsbury^1,2

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment

Direct Measurement of Low-affinity Ion Binding to Enable Precise Separation of Critical Minerals

Abstract
Diversifying supply chains for critical minerals such as lithium, nickel, cobalt, and rare earth elements is essential to meeting increasing demand for clean energy technologies. Recovery of these minerals frequently requires separating similarly sized, equally charged ions from industrial wastewaters, which is highly challenging for current engineered processes. To make such separations possible, we need to better understand the thermodynamic driving force behind specific ions interacting with chemical functional groups on these materials. Accordingly, we have developed an experimental isothermal titration calorimetry (ITC) technique—validated by density functional theory (DFT)—to quantify low-affinity ion binding to engineered separation materials. Whereas ITC is generally regarded as implausible for accurately quantifying the thermodynamics of low-affinity systems, our methodology aligns well with DFT validation and reference values in cation-cation exchange materials. This approach can be extended to anion binding system and utilized for the systematic estimation of ion-ion binding.

Bio
Park earned bachelor’s and master’s degrees in civil and environmental engineering from Seoul National University, South Korea. His research has focused on membrane and electrochemical separations for selective resource recovery with the aid of computational tools including library development, machine learning, and density functional theory. Park aims to develop integrated computational and experimental workflows for designing ion-selective engineered materials and systems to contribute to a circular economy. 

Eva S. M. Reed¹

Undergraduate Class of 2026
Principal Investigator: Emily C. Davidson¹

With Clement (Chun Lam) Chan¹ and Emily C. Ostermann¹

¹ Department of Chemical and Biological Engineering

Characterization of Chiral Self-Assembly in Sequence-Defined Mesogenic Dimers

Abstract
Liquid crystals (LCs) are phases of matter that possess properties in between those of liquids and crystalline solids. Due to the intrinsic anisotropy of calamitic LC mesogens, they frequently adopt LC and crystalline structures with useful optical, magnetic, and electronic properties. Recently, the Davidson research group has developed a general approach to using orthogonal protection/deprotection reactions to synthesize discrete and sequence defined liquid crystalline oligomers. This work examines the self-assembly of mesogenic dimers synthesized with two different mesogens: a phenyl benzoate core both with (M) and without (N) a methyl-substituted aromatic ring. The two dimers with alternating sequence (MN and NM) and their mixtures are both examined. Both pure oligomers exhibit chiral superstructures composed of ~100 nm nanocylinders; however, their crystalline morphology and phase behavior are divergent as observed via optical, thermal, and X-ray characterization. We find that blends of the two materials assemble to form banded spherulites. Scanning electron microscopy of the alternating dimers grown in the confined melt or in solvent advances our understanding of their chiral self-assemblies and motivates possible applications in chiroptical materials or catalysis via chemical functionalization of the nanostructures.

Bio
Reed is a junior pursuing a bachelor’s degree in chemical and biological engineering with a certificate in materials science and engineering and French language and culture. Her research interests include liquid crystals and block copolymers. She hopes to pursue higher education to continue materials research focusing on sustainable and green materials.

Carson Repins¹

Undergraduate Class of 2027
Principal Investigator: Michele Sarazen¹

With Jun Zhi Tan¹, Cole Hullfish¹  

¹ Department of Chemical and Biological Engineering

Plastic Upcycling on Metal-Free Hierarchical FAU Zeolites: Impacts of Mesopore Identity and Connectivity

Abstract
Traditional (e.g. mechanical) recycling methods are insufficient at addressing the plastic waste crisis. Chemical recycling methods (e.g. catalytic cracking) can convert plastic waste into valuable hydrocarbons, supplementing traditional recycling methods. Microporous zeolites containing Brønsted acid sites are promising catalysts for plastic upcycling, as the confinement effects offered by micropores accelerate C-C bond cleavage rates. However, diffusion of polymers into micropores is typically rate-limiting. Here, we incorporate mesopores into microporous FAU zeolites through different synthesis methods to determine how mesopore identity and connectivity within microporous zeolites affect plastic upcycling rates and product selectivity.

Bio
Repins is a sophomore pursuing a bachelor’s degree in chemical and biological engineering and potentially a minor in materials science and engineering. He is driven by the need to find sustainable solutions to meet energy demands combined with his passion for being at the cutting edge in materials science. Repins is a member of the Princeton University men’s heavyweight rowing team. Still having many years left in his time as an undergraduate, Repins does not have any set post-graduation plans and is open to either joining industry or pursuing further education.

Marco Rupp¹

4th year Ph.D. candidate  
Principal Investigator: Craig Arnold¹

With Shuichiro Hayashi², Ankit Das¹ 

¹ Department of Mechanical and Aerospace Engineering
² Princeton Materials Institute

Multiple-beam Laser Processing for Structural Surface Alteration of Metals

Abstract
Spatially selective melting of metal materials by laser irradiation allows for the precise welding as well as the 3D printing of complex metal parts. However, the simple scanning of a conventional Gaussian beam typically results in a melt track with randomly distributed surface features due to the complex and dynamic behavior of the melt pool. In this study, the implications of utilizing a dynamically oscillating energy input on driving melt track fluctuations are investigated. Specifically, the laser intensity and/or intensity distribution is sinusoidally modulated at different scan speeds, and the effect of modulation frequency on the resulting surface features of the melt track is examined. The formation of periodically oriented surface features indicates an evident frequency coupling between the melt pool and the modulation frequency. Moreover, such a frequency coupling becomes most prominent under a specific modulation frequency, suggesting resonant behavior.

Bio 
Rupp earned a bachelor’s degree in mathematics and mechanical and aerospace engineering from Trinity College and an incidental master’s degree in mechanical and aerospace engineering from Princeton University. His research interests include developing new laser processing techniques for advanced metal manufacturing. Rupp hopes the research will improve manufacturing techniques making them more environmentally friendly. Rupp also collaborates with researchers in the Departments of Electrical and Computer Engineering and Chemical and Biological Engineering at Princeton, as well as the Institute of Photonic Technologies and the Erlangen Graduate School in Advanced Optical Technologies at the Friedrich-Alexander Universität in Erlangen-Nürnberg, Germany. Rupp has published in Applied Physics A and the Journal of Manufacturing Processes. He is planning to continue his research in industry upon graduation.

Arjun Shetty¹

Undergraduate Class of 2027
Principal Investigator: Yiguang Ju¹

With Andy Thawko¹

¹ Department of Mechanical and Aerospace Engineering

Development of a High-pressure Combustor to Enable Ammonia Power Generation within Gas Turbine Engines

Abstract
In the face of the progressively critical issue of climate change, ammonia presents a promising zero-carbon solution for power generation. Ammonia as a hydrogen carrier possesses favorable aspects for combustion, including a high energy density and simplicity for transportation and storage. However, the existing usage of ammonia as a fuel is hindered by the emission of N₂O and NO_X pollutants, which poses a significant challenge for ammonia’s future as a carbon-free energy carrier. By changing the design for the mixing mechanism for our jet stirred reactor, measured emissions of N₂O and NO_X were reduced, which yields results favorable for the continued development of a combustor suitable for ammonia power generation.

Bio
Shetty is a sophomore pursuing a bachelor’s degree in mechanical engineering with a minor in computer science and certificate in the Program in Sustainable Energy. His research interests include combustion physics and chemistry for engines and propulsion, specifically as it relates to synthetic fuels. Shetty is a member of the Princeton University Energy Association’s publication team and a Technical Lead for the Princeton University Robotics Club. He hopes to pursue further research into the energy field, focused on enhancing alternatives to carbon based fuels.

Cuihong Song¹

Associate Research Scholar
Principal Investigator: Z. Jason Ren^1,2

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment

Recalibrating Global GHG Emissions from the Wastewater Sector in National Inventories

Abstract
Climate policy has shifted from pledge-making to implementation towards the long-term temperature goal of the Pairs Agreement. The first Global Stocktake in 2023 revealed a large gap in progress, highlighting the need for urgent reductions in non-CO₂ greenhouse gas (GHG) emissions by 2030. Wastewater treatment is a major source of non-CO₂ GHGs, primarily CH₄ and N₂O, contributing 411-632 Mt CO₂-eq annually. However, the accuracy of current wastewater GHG inventories is widely questioned due to large variations in CH₄ and N₂O emissions from wastewater treatment and substantial methodological inconsistencies in GHG accounting. Here, we investigate these inconsistencies by examining emission factors, approach tiers, and activity data used across countries, regions, and facilities. We also recalibrate global wastewater GHG emissions by updating outdated data and addressing previously omitted sources. This study aims to improve the accuracy of national GHG inventories and inform more effective mitigation strategies.

Bio
Song earned her Ph.D. degree in civil and environmental engineering from the University of New Hampshire in 2020. Her research focuses on promoting sustainability and resilience of critical infrastructures and innovative technologies. She uses interdisciplinary approaches such as big data analysis, computational models, life cycle assessment, and stakeholder engagement to study water-energy-ecosystem-carbon nexus and inform decarbonization pathways. Song has published in Nature Sustainability, Nature Water, Environmental Science & Technology, Renewable & Sustainable Energy Reviews, Science of the Total Environment, etc.

Hennessy Soto¹

Undergraduate Class of 2027
Principal Investigator: Kelsey Hatzell^1,2

¹ Department of Mechanical and Aerospace Engineering
² Andlinger Center for Energy and the Environment

Tailoring Materials for Electrochemical Separations

Abstract
Traditionally, electrochemical separation used for water treatment has utilized pressure or temperature-based driving forces to create capacitive currents that can harm the environment. Recently, it has been discovered that a new family of 2d nanomaterials called MXenes can be used for electrochemical separation due to its high capacity and ion adsorption properties. This project explores the electrochemical properties of MXenes to understand their capacitive powers.  The impact of hydronium ions on the capacitance of double-layer electrodes is also explored. Studies on the properties of MXene can be used beyond water treatment and into the realm of batteries to further help the environment.

Bio
Soto is a sophomore pursuing a bachelor’s degree in mechanical and aerospace engineering and a minor in robotics and intelligent systems. Her research interests include studying materials and their applications for sustainability efforts and robotic autonomy for space exploration. Soto is a member of the Princeton University Rocketry Club, Robotics Club, and Taekwondo team. She hopes to pursue a career in the aerospace industry, focusing on developing space vehicles for space exploration.

Vibha Srinivasan¹

Undergraduate Class of 2026
Primary Supervisor: Dominic Davis²

With Chris Grieg², Eric Larson²

¹ Department of Electrical and Computer Engineering
² Andlinger Center for Energy and the Environment

Speed Limits of the Energy Transition: Assessing the Capacity of Domestic and International Clean Energy Supply Chains: How Do We Ramp Up?

Abstract
Deep decarbonization of society requires rapid expansion of clean energy supply chains and deployment of clean energy technology capacity across the globe. However, various bottlenecks, constraints, and barriers limit the speed of the required energy transition, both domestically and internationally, risking achievement of net-zero emissions goals. This project, in a broad sense, will attempt to assess the supply chain demands of America’s energy transition and provide solutions in order to speed up the availability of critical energy technologies and resources. Key frameworks we consider include expansion/deployment of electric vehicles (through data analysis and database formation) as well as how capacity models account for inter-annual build constraints (through a literature review).

Bio
Srinivasan is a junior pursuing a bachelor’s degree in electrical and computer engineering as well as a minor in sustainable energy. Her research interests, outside of the renewable energy field, include utilizing optical fibers to bolster medical device scanning and promote earlier detection of neurological diseases. Srinivasan is incredibly interested in visual and performing arts, and leads Princeton’s cultural Bhangra and Bharatanatyam dance groups, as well as its Carnatic vocal ensemble, Swara. She hopes to pursue a career that will enable her to innovate inclusive, interdisciplinary, and eco-friendly technologies to improve the lives of those around her.

Sui Xiong Tay ¹

2nd year Ph.D. candidate
Principal Investigator: Ryan Kingsbury^2,3

¹ Department of Mechanical and Aerospace Engineering
² Andlinger Center for Energy and the Environment
³ Department of Civil and Environmental Engineering

Accelerated Discovery of Ion Selective Electrodes for Industrial Wastewater Refining

Abstract
Heavy metals like lead, cobalt, copper, and nickel are both essential ingredients in clean energy technologies and toxic substances that contribute to environmental harm when they enter the environment. Historically, these metals have been obtained by mining, but a variety of industrial wastewaters also contain significant metal resources that, if captured, would stabilize supply chains and reduce environmental challenges associated with mining. Prussian Blue Analogues (PBAs), a family of ion-adsorptive materials that have shown great promise in aqueous batteries, hold great promise for selectively adsorbing dissolved metals in a process called capacitive deionization (CDI). This work seeks to identify PBA chemistries that are suitable for targeted metal removal by adopting a high throughput density functional theory (DFT) screening process.

Bio
Tay earned a bachelor’s degree in materials science and engineering from Purdue University. His research interests include leveraging both computational and experimental techniques for designing/discovering/developing (3Ds) new materials for electrochemical resource recovery and desalination purposes. Tay hopes this research will lay a solid foundational understanding on the physical and chemical properties of PBAs in aqueous environments. Upon narrowing down promising candidate PBA materials, Tay hopes that these materials can be then tested/verified in lab environments and ultimately, scaled into large-scale production when feasible. As an undergraduate, Tay co-authored articles on lead-free solders in the Journal of Electronic Materials and MRS Advances.

Hansen Tjo¹

4th year Ph.D. candidate 
Principal Investigator: Jonathan Conway¹

With Anherutowa Calvo¹

¹ Department of Chemical and Biological Engineering

Lignocellulosic Oligosaccharide Uptake in the Extreme Thermophile Anaerocellum bescii for Engineered Biofuels Production

Abstract
Lignocellulosic biofuels and biochemicals are the building blocks to sustainable, bio-based supply chains. Anaerocellum bescii, an extremely thermophilic bacterium (Topt ~ 75 C), is a promising metabolic engineering host due to its innate ability to degrade lignocellulose and ferment a broad range of lignocellulosic substrates through its inventory of ATP-Binding Cassette (ABC) sugar transporters. Nevertheless, the potential of A. bescii as a model microbial platform is constrained by a limited understanding of ABC transporter sugar-specificity. Here, we utilize in vitro assays and in vivo genetics to investigate the previously unknown substrate preferences for lignocellulose-relevant ABC transporters. Through biophysical screens and protein crystallography, we identified key transporters underlying xyloglucan and cellodextrin uptake; we are currently studying phenotypic effects of deleting these transporters. Our results clarify how A. bescii utilizes a diverse array of lignocellulosic substrates, lending insights to rewiring its native metabolism for producing renewable fuels and chemicals at elevated yields.

Bio
Tjo is a 4th year Ph.D. student in chemical engineering at Princeton and is advised by Jonathan Conway. Tjo’s work focuses on understanding and engineering sugar transport in the extremely thermophilic, lignocellulose-degrading bacterium Anaerocellum bescii for renewable fuels production. His work is supported by the High Meadows Environmental Institute and the Roberto Rocca Education Program.

Jessica Wang¹

Undergraduate Class of 2027 
Principal Investigator: A. James Link¹

With Toby Johnson¹, Drew Carson¹, Dawood Virk¹

¹ Department of Chemical and Biological Engineering

Engineering of Thermostable Plastic Degrading Enzymes

Abstract
Following the increased production of plastic wastes in recent years, certain types of plastics, such as polyethylene terephthalate (PET), pose significant environmental challenges due to their non-biodegradable nature. Enzymes capable of degrading PET into its monomers, also known as PETases, struggle to meet temperature demands optimal for efficient degradation of untreated postconsumer PET. This project hence proposes the insertion of PETase enzymes into a ribosomally synthesized and post translationally modified peptide (RiPPs) named fuscimiditide, which is shown to install two ester cross-links that may improve the thermostability of PETases. Initial experiments suggest that the formation of cyclic PETase with ester-linkages is possible with the addition of a 6-glycine linker in the pre-fuscimiditide sequence, with the PETase still retaining, and even possibly enhancing, its PET degrading functionality at higher temperatures.

Bio
Wang is a sophomore pursuing a bachelor’s degree in chemical and biological engineering with minors in material science and computer science. Her research interests focus on developing sustainable chemical and biological solutions to plastic materials, such as polyethylene (PE) and polyethylene terephthalate (PET). She is passionate about improving sustainability in plastic industries and hopes to apply her engineering knowledge about materials in a practical, industrial setting in the future.

Kaya Unalmis¹

Undergraduate Class of 2025
Principal Investigator: Egemen Kolemen^2,3,4

With Rahul Gaur³, Rory Conlin⁵, D. Dudt⁶, D. Panici³, Y. Elmacioglu³, K. Orr³

¹ Department of Electrical and Computer Engineering
² Andlinger Center for Energy and the Environment
³ Department of Mechanical and Aerospace Engineering
⁴ Princeton Plasma Physics Laboratory
⁵ University of Maryland
⁶ Thea Energy

Stellarator Optimization Using Proxies for Neoclassical Transport and Energetic Particle Confinement

Abstract
To confine a stellarator plasma, a magnetic field must be created where the field lines form nested surfaces by twisting around a toroidal shape. For such a three-dimensional field, particles with low speed parallel to the magnetic field are lost by an unoptimized stellarator. The resulting particle orbits caused by such particles lead to neoclassical transport, which can become the dominant transport in unoptimized stellarators. We have developed and implemented an automatically-differentiable algorithm to compute optimization metrics such as the effective ripple for neoclassical transport, and fast particle confinement in the DESC optimization suite.

Bio
Unalmis is pursuing a bachelor’s degree in electrical engineering with minors in engineering physics, mathematics, and computer science. He is interested in plasma physics and optimization, especially in the context of fusion. He is working on stellarator optimization (fusion reactors that confine plasma with magnetic fields) in the Plasma Control group. He hopes to continue his studies in physics for fusion research.

David Wang¹

Undergraduate Class of 2027
Principal Investigator: Egemen Kolemen^2,3

With Azarakhsh Jalalvand³, Andy Rothstein³

¹ Department of Electrical and Computer Engineering
² Andlinger Center for Energy and the Environment
³ Department of Mechanical and Aerospace Engineering

Machine Learning Surrogate Model for Real-Time ECH Deposition Profiles in Nuclear Fusion Reactors

Abstract
The DIII-D tokamak employs gyrotrons to emit microwave beams that heat up the plasma, in a process called Electron Cyclotron Heating (ECH). It is important to understand how these ECH beams affect both the temperature and current drive of the plasma in order to control heating and mitigate plasma instabilities such as Tearing Modes and ELMs. Currently, researchers use a physics-based ray-tracing code to calculate these heating profiles, but the model is slow and inadequate for advanced real-time ECH profile optimization. The goal of the project is to build a machine learning surrogate to predict the full temperature and current drive profiles in the plasma, adjusting quickly and accurately for plasma instabilities. The input features to the model involve plasma equilibria geometry data along with electron density and temperature profiles. By reducing the dimensionality of the ECH profiles using Gaussian curve fitting, we create an efficient data pipeline for the model. We optimize the hyperparameters for a multilayer perceptron neural network, steadily improving the accuracy of its predictions.

Bio
Wang is a sophomore pursuing a bachelor’s degree in electrical and computer engineering and a minor in the Program in Sustainable Energy. His research interests include developing machine learning models to address environmental needs. Wang also collaborates with researchers in the Department of Mechanical and Aerospace Engineering and the Princeton Plasma Physics Laboratory. Wang is a member of the Princeton Rocketry SA Cup Team. He hopes to pursue a career in technology or aerospace engineering, focused on exploring the applications of AI and machine learning.

Andrew Yang¹

Undergraduate Class of 2026
Principal Investigator: Chris Greig²

With Dominic Davis²

¹ Department of Operations Research and Financial Engineering
² Andlinger Center for Energy and the Environment

Optimal Development Sequences for Energy Assets via Critical Path Model

Abstract

Optimizing the development sequences of energy assets is essential for advancing the energy transition and the ultimate goal of reaching net zero emissions by 2050. This project applies a critical path model to identify key activities and bottlenecks that could delay asset deployment. By developing a Python script, we calculate the earliest and latest start and finish times for each task, determining the slack and pinpointing critical paths. While current limitations arise from

assets having to wait for previous ones to fully finish, future work will explore more flexible deployment strategies. These insights will aid policymakers and stakeholders in enhancing the efficiency of energy transitions and navigating policy impacts.

Bio

Yang is a junior pursuing a bachelor’s degree in operations research and financial engineering and a minor in computer science. His research interests lie at the intersection of machine learning, convex optimization, and stochastic finance. Yang also collaborates with researchers in the Andlinger Center for Energy and the Environment. Yang is a member of the Princeton University Sinfonia and badminton team. He is also an active member of Annex Capital Partners, a student-run long/short investment fund. He hopes to pursue a career in finance, focused on utilizing machine learning techniques and technology to ensure market efficiency.

Meiqi Yang¹

5th year Ph.D. candidate
Principal Investigator: Z. Jason Ren^1,2

with Fernando Temprano-Coleto², Hongxu Chen¹

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment

Efficient Lithium Extraction from Oilfield Brines with an Advanced Evaporative Process

Abstract
Lithium is a critical mineral with a rapidly growing global market, and oilfield brines are recognized as promising sources for lithium supply. However, current extraction techniques, such as evaporation ponds and direct lithium extraction methods, face significant challenges due to low lithium concentrations and limited selectivity between lithium and other monovalent ions. These issues make lithium extraction from oilfield brines inefficient and economically discouraging. In this study, we demonstrate a novel lithium extraction process with top-down configuration for gravity-facilitated capillarity flow. The process achieves evaporation rates three orders of magnitude higher (341 vs. 0.12 kg h^-1 m^-2) than traditional evaporation ponds under same environmental condition, significantly reducing processing time to a few hours. During the process, lithium concentration is enriched from 96 to 52,768 ppm. Additionally, this process demonstrates high selectivity between Li⁺ and Na⁺ ions (selectivity = 3,523), presenting a potential game changer for lithium extraction from oilfield brines.

Bio
Yang earned her bachelor’s degree in environmental science from Shandong University and a master’s degree in environmental engineering from Yale University. Her research interests lie at the water-energy nexus, focusing on wastewater treatment and applying advanced separation processes to improve resource recovery. Specifically, she works on the development, evaluation, and implementation of evaporation processes and membrane technology. Her research includes laboratory development, AI/machine learning analysis, and system assessment and optimization. She aims to not only advance the science of separation technologies but also to offer more efficient and cost-effective solutions for resource recovery, pollution reduction, and human health protection.

Anita Zhang¹

4th year Ph.D. candidate
Principal Investigator: Claire E. White^1,2

¹ Department of Civil and Environmental Engineering
² Andlinger Center for Energy and the Environment

Impact of Reduced Sodium Concentration and Addition of Alkali Earth Oxide/Hydroxide on the Permeability of Alkali-activated Metakaolin

Abstract
Alkali-activated metakaolin (AAMK), a product of combining calcined kaolinite clay with an alkali activator such as a sodium silicate solution, is a promising type of sustainable alternative cement that emits 40-80% less CO₂ than ordinary Portland cement. Currently, in a standard AAMK mix design, most of its costs and remaining emissions come from the activator, so lowering the alkali concentration of the activator is of interest. However, the question remains as to what can be added to mix designs with low activator concentrations to minimize both short-term and long-term performance loss while maintaining a lower carbon footprint. In this study, using various pore size characterization techniques and three-point beam bending permeability tests, we show that two cation sources, calcium hydroxide (Ca(OH)₂) and magnesium oxide (MgO), may help offset the performance loss associated with lower activator concentrations. The mechanism through which they helped was then studied using Fourier transform infrared spectroscopy and isothermal conduction calorimetry. Findings from our work can aid in the design and optimization of future AAMK formulations to achieve both low CO₂ emissions and good performance properties.

Bio
Zhang graduated from Cornell University with a bachelor’s degree in December 2020, majoring in civil engineering and minoring in applied math. Before Princeton, she worked at a sustainability-minded civil engineering B-Corp, Taitem Engineering, in Ithaca, NY and completed two internships with Arup’s Advanced Technology and Research team in New York City. At Princeton, she focuses on understanding and optimizing the durability of alkali-activated metakaolin using a variety of material characterization techniques. She is also the recipient of the High Meadows Environmental Institute’s Science, Technology, and Environmental Policy fellowship. She is currently working on her first manuscript, and she hopes her work can lead to wider adoption of sustainable cement.