On a cloudy spring day in Atlanta, Rich Simmons, director of research and studies at the Georgia Tech Strategic Energy Institute (SEI), led a group of a dozen student volunteers to the roof of the Carbon Neutral Energy Solutions Laboratory (CNES). The students were part of the nearly 300 student volunteers participating in Georgia Tech Beautification Day and visited CNES to clean the building’s rooftop solar array made of photovoltaic (PV) panels. The CNES building entered operation in 2011 and its panels have accumulated grime over the years, impacting their efficiency.

Simmons explained the importance of this project, emphasizing how cleaning the panels restores their efficiency and contributes to ongoing research. "We've used this project to better understand PV efficiency in an urban environment and have instrumented the newly cleaned arrays to continue monitoring. An initial study last year suggested efficiency could increase by 10-20% just from a thorough cleaning. This project is both a handy research tool, an educational conduit, and a means of campus engagement related to sustainability," he shared.

Safety was paramount, and proactive communication between the research, health and safety, and infrastructure and sustainability teams ensured a successful event. Equipped with hard hats, eye protection, and high-visibility safety vests, the students scrubbed the panels with sponges and bristle brushes. The hands-on experience was both educational and rewarding.

After cleaning, Simmons led the group to the inverter room, where the DC electricity generated by the panels is converted into AC so that it can be consumed within the building or exported to the campus grid. He explained that excess solar power can also be stored in the newly installed 150-kWh Stryten battery system or used to charge campus vehicles through the newly installed EV chargers in the building’s parking lot. He demonstrated how magnetic monitoring devices measure the electricity produced by the arrays, allowing for a comparison of the efficiency of panels that were just cleaned, to those that were cleaned last year, and those that have never been cleaned in the 13 years since their installation.

Through initiatives like this, Georgia Tech continues to lead in research and education, inspiring the next generation of innovators and problem-solvers.

This article was written with the assistance of Microsoft Copilot (Apr. 9, 2025) and edited by Georgia Tech EPIcenter's Gilbert X. Gonzalez and Rich Simmons.

For centuries, innovations in structural materials have prioritized strength and durability — often at a steep environmental price. Today, the construction industry accounts for approximately 10% of global greenhouse gas emissions, with cement, steel, and concrete responsible for more than two-thirds of that total. As the world presses for a sustainable future, scientists are racing to reinvent the very foundations of our built environment.

Paradigm Shift in Construction

Now, researchers at Georgia Tech have developed a novel class of modular, reconfigurable, and sustainable building blocks — a new construction paradigm as well-suited for terrestrial homes as it is for extraterrestrial habitats. Their study, published in Matter, demonstrates that these innovative units, dubbed eco-voxels, can reduce carbon footprints by up to 40% compared to traditional construction materials. These units also maintain the structural performance needed for applications ranging from load-bearing walls to aircraft wings.

“We created sustainable structures using these eco-friendly building blocks, combining our knowledge of structural mechanics and mechanical design with industry-relevant manufacturing practices and environmental assessments,” said Christos Athanasiou, assistant professor at the Daniel Guggenheim School of Aerospace Engineering.

Housing Affordability Solutions

Their work offers a potential solution to the growing housing affordability crisis. As climate-driven disasters such as hurricanes, wildfires, and floods increase, homes are damaged at higher rates, and insurance costs are skyrocketing. This crisis is fueled by rising land prices and restrictive development regulations. Meanwhile, the growing demand for housing places an increasing strain on global resources and the environment. The modularity and circularity of the developed approach can effectively address these issues. 

The New Building Blocks

Eco-voxels — short for eco-friendly voxels, the 3D equivalent of pixels — are made from polytrimethylene terephthalate (PTT). PTT is a partially bio-based polymer derived from corn sugar and reinforced with recycled carbon fibers from aerospace waste (scrap material lost during the manufacturing of aerospace components). Eco-voxels can be easily assembled into large, load-bearing structures and then disassembled and reconfigured, all without generating waste. Consequently, they offer a highly adaptable, sustainable approach to construction.

The team tested eco-voxels and found they can handle the pressure that buildings usually face. They also used computer simulations to show that changing the shape of eco-voxels makes them suitable for many different building needs.

The researchers compared the eco-voxel approach to other emerging construction methods like 3D-printed concrete and cross-laminated timber (CLT), finding that eco-voxels offer significant environmental advantages. While traditional and alternative materials are often heavy and carbon-intensive, the eco-voxel wall had the lowest carbon footprint: 30% lower than concrete and 20% lower than CLT.

These results highlight eco-voxels as a promising low-carbon, high-performance solution for sustainable and affordable construction, opening new possibilities for faster, more sustainable building solutions. In addition to residential uses, emergency shelters built with eco-voxels could be used for disaster-relief scenarios, where quick assembly, modularity, and minimal environmental impact are crucial.

In July 2024, the Strategic Energy Institute (SEI), in partnership with the Georgia Tech Research Institute (GTRI), launched the Energy and National Security Initiative through a campuswide workshop. The event attracted over 100 participants from units across Georgia Tech and GTRI. John Tien, SEI distinguished external fellow, professor of the practice, and former deputy secretary for the Department of Homeland Security, along with Tom Fanning, former CEO at Southern Company, kicked off the workshop with a discussion on the role of energy in national security and the opportunities for Georgia Tech to align its research with this critical topic. 

The event concluded with the announcement of two rounds of seed funding, offering up to $500,000 annually for three years. The first round, announced in September 2024, provided planning grants to six teams to support their initiatives in the fall.  

Recipients of the second phase of seed funding have now been announced. This phase will provide research support in the spring, with an option for additional funding through the 2025-26 academic year. 

“This seed funding initiative by SEI and GTRI is a significant step toward advancing national security through innovative energy solutions. We believe this support will empower the funded teams to explore critical intersections between energy infrastructure and security, fostering groundbreaking advancements for a safer energy future,” said Christine Conwell, SEI’s interim executive director.  

Seven interdisciplinary projects by team members from Georgia Tech and GTRI have been selected for the second phase, also known as Category B. The projects include:

“The seed grant initiative is supporting energy and national security collaboration among researchers from multiple units across the Georgia Tech campus,” said William H. Robinson, interim chief technology officer and deputy director for Research in GTRI’s Information and Cyber Sciences Directorate. “We are very pleased to see the teamwork of these faculty members as they address important issues facing our nation.”

A follow-up workshop will be held this summer to bring together the awardees of the seed grant program. Additionally, a lunch and learn seminar series is planned in the fall to showcase the research progress of the seed grant program. For updates, visit the Strategic Energy Institute event webpage.

When the International Maritime Organization enacted a mandatory cap on the sulfur content of marine fuels in 2020, with an eye toward reducing harmful environmental and health impacts, it left shipping companies with three main options.

They could burn low-sulfur fossil fuels, like marine gas oil, or install cleaning systems to remove sulfur from the exhaust gas produced by burning heavy fuel oil. Biofuels with lower sulfur content offer another alternative, though their limited availability makes them less feasible.

While installing exhaust gas cleaning systems, known as scrubbers, is the most feasible and cost-effective option, there has been a great deal of uncertainty among firms, policymakers, and scientists as to how “green” these scrubbers are.

Through a novel lifecycle assessment, researchers from Georgia Tech, MIT, and elsewhere have now found that burning heavy fuel oil with scrubbers in the open ocean can match or surpass using low-sulfur fuels, when a wide variety of environmental factors is considered.

The scientists combined data on the production and operation of scrubbers and fuels with emissions measurements taken onboard an oceangoing cargo ship.

They found that, when the entire supply chain is considered, burning heavy fuel oil with scrubbers was the least harmful option in terms of nearly all 10 environmental impact factors they studied, such as greenhouse gas emissions, terrestrial acidification, and ozone formation.

“In our collaboration with Oldendorff Carriers to broadly explore reducing the environmental impact of shipping, this study of scrubbers turned out to be an unexpectedly deep and important transitional issue,” said Neil Gershenfeld, an MIT professor, director of the Center for Bits and Atoms (CBA), and senior author of the study.

“Claims about environmental hazards and policies to mitigate them should be backed by science. You need to see the data, be objective, and design studies that take into account the full picture to be able to compare different options from an apples-to-apples perspective,” added lead author Patricia Stathatou, an assistant professor at Georgia Tech, who began this study as a postdoc in the CBA.

Stathatou is joined on the paper by Michael Triantafyllou and others at Naias Laboratories, the National Technical University of Athens in Greece, and the maritime shipping firm Oldendorff Carriers. The research appeared recently in Environmental Science and Technology.

Slashing sulfur emissions

Heavy fuel oil, traditionally burned by bulk carriers that make up about 30 percent of the global maritime fleet, usually has a sulfur content around 2 to 3 percent. This is far higher than the International Maritime Organization’s 2020 cap of 0.5 percent in most areas of the ocean and 0.1 percent in areas near population centers or environmentally sensitive regions.

Sulfur oxide emissions contribute to air pollution and acid rain, and can damage the human respiratory system.

In 2018, fewer than 1,000 vessels employed scrubbers. After the cap went into place, higher prices of low-sulfur fossil fuels and limited availability of alternative fuels led many firms to install scrubbers so they could keep burning heavy fuel oil.

Today, more than 5,800 vessels utilize scrubbers, the majority of which are wet, open-loop scrubbers.

“Scrubbers are a very mature technology. They have traditionally been used for decades in land-based applications like power plants to remove pollutants,” Stathatou explained.

A wet, open-loop marine scrubber is a huge, metal, vertical tank installed in a ship’s exhaust stack, above the engines. Inside, seawater drawn from the ocean is sprayed through a series of nozzles downward to wash the hot exhaust gases as they exit the engines.

The seawater interacts with sulfur dioxide in the exhaust, converting it to sulfates — water-soluble, environmentally benign compounds that naturally occur in seawater. The washwater is released back into the ocean, while the cleaned exhaust escapes to the atmosphere with little to no sulfur dioxide emissions.

But the acidic washwater can contain other combustion byproducts like heavy metals, so scientists wondered if scrubbers were comparable, from a holistic environmental point of view, to burning low-sulfur fuels.

Several studies explored toxicity of washwater and fuel system pollution, but none painted a full picture.

The researchers set out to fill that scientific gap.

A “well-to-wake” analysis

The team conducted a lifecycle assessment using a global environmental database on production and transport of fossil fuels, such as heavy fuel oil, marine gas oil, and very-low sulfur fuel oil. Considering the entire lifecycle of each fuel is key, since producing low-sulfur fuel requires extra processing steps in the refinery, causing additional emissions of greenhouse gases and particulate matter.

“If we just look at everything that happens before the fuel is bunkered onboard the vessel, heavy fuel oil is significantly more low-impact, environmentally, than low-sulfur fuels,” Stathatou said.

The researchers also collaborated with a scrubber manufacturer to obtain detailed information on all materials, production processes, and transportation steps involved in marine scrubber fabrication and installation.

“If you consider that the scrubber has a lifetime of about 20 years, the environmental impacts of producing the scrubber over its lifetime are negligible compared to producing heavy fuel oil,” she noted.

For the final piece, Stathatou spent a week onboard a bulk carrier vessel in China to measure emissions and gather seawater and washwater samples. The ship burned heavy fuel oil with a scrubber and low-sulfur fuels under similar ocean conditions and engine settings.

Collecting these onboard data was the most challenging part of the study.

“All the safety gear, combined with the heat and the noise from the engines on a moving ship, was very overwhelming,” she said.

Their results showed that scrubbers reduce sulfur dioxide emissions by 97 percent, putting heavy fuel oil on par with low-sulfur fuels according to that measure. The researchers saw similar trends for emissions of other pollutants like carbon monoxide and nitrous oxide.

In addition, they tested washwater samples for more than 60 chemical parameters, including nitrogen, phosphorus, polycyclic aromatic hydrocarbons, and 23 metals.

The concentrations of chemicals regulated by the IMO were far below the organization’s requirements. For unregulated chemicals, the researchers compared the concentrations to the strictest limits for industrial effluents from the U.S. Environmental Protection Agency and European Union.

Most chemical concentrations were at least an order of magnitude below these requirements.

In addition, since washwater is diluted thousands of times as it is dispersed by a moving vessel, the concentrations of such chemicals would be even lower in the open ocean.

These findings suggest that the use of scrubbers with heavy fuel oil can be considered as equal to or more environmentally friendly than low-sulfur fuels across many of the impact categories the researchers studied.

“This study demonstrates the scientific complexity of the waste stream of scrubbers. Having finally conducted a multiyear, comprehensive, and peer-reviewed study, commonly held fears and assumptions are now put to rest,” said Scott Bergeron, managing director at Oldendorff Carriers and co-author of the study.

“This first-of-its-kind study on a well-to-wake basis provides very valuable input to ongoing discussion at the IMO,” said Thomas Klenum, executive vice president of innovation and regulatory affairs at the Liberian Registry, emphasizing the need “for regulatory decisions to be made based on scientific studies providing factual data and conclusions.”

Ultimately, this study shows the importance of incorporating lifecycle assessments into future environmental impact reduction policies, Stathatou said.

“There is all this discussion about switching to alternative fuels in the future, but how green are these fuels? We must do our due diligence to compare them equally with existing solutions to see the costs and benefits,” she concluded.

In addition to Georgia Tech and MIT, Mario Tsezos' team from Naias Labs in Greece contributed significantly to the research. This study was supported in part by Oldendorff Carriers. 

- Written by Adam Zewe, MIT News Office

Many communities rely on insights from computer-based models and simulations. This week, a nest of Georgia Tech experts are swarming an international conference to present their latest advancements in these tools, which offer solutions to pressing challenges in science and engineering.

Students and faculty from the School of Computational Science and Engineering (CSE) are leading the Georgia Tech contingent at the SIAM Conference on Computational Science and Engineering (CSE25). The Society of Industrial and Applied Mathematics (SIAM) organizes CSE25, occurring March 3-7 in Fort Worth, Texas.

At CSE25, the School of CSE researchers are presenting papers that apply computing approaches to varying fields, including:                   

• Experiment designs to accelerate the discovery of material properties
• Machine learning approaches to model and predict weather forecasting and coastal flooding
• Virtual models that replicate subsurface geological formations used to store captured carbon dioxide
• Optimizing systems for imaging and optical chemistry
• Plasma physics during nuclear fusion reactions

[Related: GT CSE at SIAM CSE25 Interactive Graphic] 

“In CSE, researchers from different disciplines work together to develop new computational methods that we could not have developed alone,” said School of CSE Professor Edmond Chow. 

“These methods enable new science and engineering to be performed using computation.” 

CSE is a discipline dedicated to advancing computational techniques to study and analyze scientific and engineering systems. CSE complements theory and experimentation as modes of scientific discovery. 

Held every other year, CSE25 is the primary conference for the SIAM Activity Group on Computational Science and Engineering (SIAG CSE). School of CSE faculty serve in key roles in leading the group and preparing for the conference.

In December, SIAG CSE members elected Chow to a two-year term as the group’s vice chair. This election comes after Chow completed a term as the SIAG CSE program director. 

School of CSE Associate Professor Elizabeth Cherry has co-chaired the CSE25 organizing committee since the last conference in 2023. Later that year, SIAM members reelected Cherry to a second, three-year term as a council member at large. 

At Georgia Tech, Chow serves as the associate chair of the School of CSE. Cherry, who recently became the associate dean for graduate education of the College of Computing, continues as the director of CSE programs. 

“With our strong emphasis on developing and applying computational tools and techniques to solve real-world problems, researchers in the School of CSE are well positioned to serve as leaders in computational science and engineering both within Georgia Tech and in the broader professional community,” Cherry said. 

Georgia Tech’s School of CSE was first organized as a division in 2005, becoming one of the world’s first academic departments devoted to the discipline. The division reorganized as a school in 2010 after establishing the flagship CSE Ph.D. and M.S. programs, hiring nine faculty members, and attaining substantial research funding.

Ten School of CSE faculty members are presenting research at CSE25, representing one-third of the School’s faculty body. Of the 23 accepted papers written by Georgia Tech researchers, 15 originate from School of CSE authors.

The list of School of CSE researchers, paper titles, and abstracts includes:
Bayesian Optimal Design Accelerates Discovery of Material Properties from Bubble Dynamics
Postdoctoral Fellow Tianyi Chu, Joseph Beckett, Bachir Abeid, and Jonathan Estrada (University of Michigan), Assistant Professor Spencer Bryngelson
[Abstract]

Latent-EnSF: A Latent Ensemble Score Filter for High-Dimensional Data Assimilation with Sparse Observation Data
Ph.D. student Phillip Si, Assistant Professor Peng Chen
[Abstract]

A Goal-Oriented Quadratic Latent Dynamic Network Surrogate Model for Parameterized Systems
Yuhang Li, Stefan Henneking, Omar Ghattas (University of Texas at Austin), Assistant Professor Peng Chen
[Abstract]

Posterior Covariance Structures in Gaussian Processes
Yuanzhe Xi (Emory University), Difeng Cai (Southern Methodist University), Professor Edmond Chow
[Abstract]

Robust Digital Twin for Geological Carbon Storage
Professor Felix Herrmann, Ph.D. student Abhinav Gahlot, alumnus Rafael Orozco (Ph.D. CSE-CSE 2024), alumnus Ziyi (Francis) Yin (Ph.D. CSE-CSE 2024), and Ph.D. candidate Grant Bruer
[Abstract]

Industry-Scale Uncertainty-Aware Full Waveform Inference with Generative Models
Rafael Orozco, Ph.D. student Tuna Erdinc, alumnus Mathias Louboutin (Ph.D. CS-CSE 2020), and Professor Felix Herrmann
[Abstract]

Optimizing Coupled Systems: Insights from Co-Design Imaging and Optical Chemistry
Assistant Professor Raphaël Pestourie, Wenchao Ma and Steven Johnson (MIT), Lu Lu (Yale University), Zin Lin (Virginia Tech)
[Abstract]

Multifidelity Linear Regression for Scientific Machine Learning from Scarce Data
Assistant Professor Elizabeth Qian, Ph.D. student Dayoung Kang, Vignesh Sella, Anirban Chaudhuri and Anirban Chaudhuri (University of Texas at Austin)
[Abstract]

LyapInf: Data-Driven Estimation of Stability Guarantees for Nonlinear Dynamical Systems
Ph.D. candidate Tomoki Koike and Assistant Professor Elizabeth Qian
[Abstract]

The Information Geometric Regularization of the Euler Equation
Alumnus Ruijia Cao (B.S. CS 2024), Assistant Professor Florian Schäfer
[Abstract]

Maximum Likelihood Discretization of the Transport Equation
Ph.D. student Brook Eyob, Assistant Professor Florian Schäfer
[Abstract]

Intelligent Attractors for Singularly Perturbed Dynamical Systems
Daniel A. Serino (Los Alamos National Laboratory), Allen Alvarez Loya (University of Colorado Boulder), Joshua W. Burby, Ioannis G. Kevrekidis (Johns Hopkins University), Assistant Professor Qi Tang (Session Co-Organizer)
[Abstract]

Accurate Discretizations and Efficient AMG Solvers for Extremely Anisotropic Diffusion Via Hyperbolic Operators
Golo Wimmer, Ben Southworth, Xianzhu Tang (LANL), Assistant Professor Qi Tang 
[Abstract]

Randomized Linear Algebra for Problems in Graph Analytics
Professor Rich Vuduc
[Abstract]

Improving Spgemm Performance Through Reordering and Cluster-Wise Computation
Assistant Professor Helen Xu
[Abstract]

Jud Ready first visited Beaverbrook Park for an adopt-a-stream event as a graduate student. When he moved to the northwest Atlanta neighborhood, he got involved with improvement efforts at the park. 

“It was a muddy mess back then. Over time, we added an exercise trail, playgrounds, a gazebo, and ball fields, but we didn't have a place where you could just walk through the woods,” Ready said. The problem? A creek prevented easy passage, and the park lacked a bridge to cross it.

Despite receiving a grant from Park Pride, a nonprofit that helps residents improve their parks, Ready realized it wasn’t nearly enough money to build a bridge over the rushing waters. Then Ready, a principal research engineer at the Georgia Tech Research Institute with a joint appointment in the School of Materials Science and Engineering, learned that one of his colleagues was using decommissioned wind turbine blades for bridges.

For eight years, Russell Gentry, a professor in the School of Architecture and a member of the Re-Wind Network, has explored how to upcycle wind turbine blades into functional infrastructure. Re-Wind, an international organization, has constructed two bridges in Ireland, where wind energy is more prevalent. The Beaverbrook bridge is the first in the U.S., but building it hasn’t been a simple copy-and-paste process from across the Atlantic Ocean.

“It's not recycling because we're not taking the material back to its original state; it's really adaptive reuse,” explained Gentry. “Think of it as the difference between wood and paper. You can take a tree and grind it up finely for paper, but if you leave it in its original form, you have wood. It’s a much more capable material from a structural perspective.” 

Like almost everything in America, the blades are bigger than their European counterparts.  The 15-meter blade weighs around 7,000 pounds, so moving it from its first home in a Colorado wind farm to a Georgia public park was no easy feat. With funding from the National Science Foundation, the Department of Energy, and wind turbine manufacturer Siemens Gamesa, Ready and Gentry established a team of a dozen Georgia Tech students, researchers, and alumni to bring the blade to Beaverbrook Park. 

Cayleigh Nicholson (architecture), Sakshi Kakkad (computing and architecture), who both graduated in 2024, and fourth-year civil engineering student Gabriel Ackall made sure the bridge was engineered well and that it complied with city regulations. Nicholson spent a semester surveying Beaverbrook to determine the best path and placement of the bridge. Kakkad developed software to better understand the geometry of the blade and position it in the bridge. Ackall was involved in the design process, working with the foundation contractor, Cantsink, to calculate stresses and deflections in the BladeBridges.  

“We’ve essentially had to design the entire structural system of the bridge from scratch, as existing building and bridge codes do not have much information about either the composite materials used in wind turbine blades or in adaptive reuse for new construction,” Ackall noted. “We used advanced modeling software combined with the knowledge we’ve gained from over a half dozen years of wind turbine blade testing and prototyping to make the bridge a reality and ensure their safety.” 

Even alumnus Tierson Boutte, CE 2002, who owns the tree company Boutte Tree, helped make the installation possible. “We’re grateful to be able to give back to the community by pruning the trees for the crane to be able to lift the turbine blades,” he said. 

On a sunny day in mid-March, the bridge was installed with a combined crew of 16 from Chappell Construction, led by alumnus  Wade Chappell, IE  2000; Williams Erection Company, owned by alumnus Art Williams, CE 1983; and ironworkers from Local 387. Finally, with a little help from an unusual source, a neighborhood can fully enjoy its park.

Video by Maxwell Guberman 
Photos by Allison Carter