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Research Spotlights

Contact with contaminated surfaces is one of the most common ways for illness to spread. A person carrying a pathogen touches something, like a doorknob, then another person touches that object and they can be infected by that pathogen. In between these contacts, the pathogen has to survive on the object, and in a large enough quantity to infect another person. Dustin Gilbert, assistant professor of materials science and engineering, wants to make it impossible, or at least unlikely, for pathogens to survive on a surface.

“If you come into contact with a surface containing pathogens, you could get sick from it, so it’s important to have surfaces that are inhospitable environments for pathogens so they just die quickly rather than being picked up and infecting another person,” said Gilbert.

Most commonly used surfaces are not good at killing pathogens. Pathogens on stainless steel, for example, can take up to five days to die on the surface; on cloth surfaces the timeframe is closer to weeks. However, there are a variety of metals that do a great job killing pathogens. Historically, colloidal silver and brass have both been used for their anti-pathogenic properties. Gilbert’s team wants to leverage the naturally occurring anti-pathogenic properties of these metals to create a more thoroughly inhospitable surface.

“Our idea was to take several of these bioactive metals and put them together into an alloy so effective that whatever pathogen lands on the surface will be attacked my multiple modes of action thanks to the properties of the individual metals,” said Gilbert. “Our goal is to protect against a broader spectrum of pathogens and kill them faster.“

Traditionally, testing these alloys would be a lengthy, laborious process in which each composition is fabricated one piece at a time and tested individually. To overcome this issue Gilbert leveraged his experience in nanotechnology to develop a nanoscale film, enabling him to test thousands of compositions in a single sample.

His team collaborated with Thomas Denes, assistant professor in the Department of Food Science at UTIA, and Anne Murray, a postdoc in Ecology and Environmental Biology, to conduct pathogen testing on the various alloy compositions. Once complete, the team came together to develop an understanding of the ways in which materials science and biology can work together to address pathogens. The results have been promising and the teams have a joint publication in progress.

Gilbert has also worked with his ORNL collaborators, Ying Yang and Easo George in the Alloy Behavior and Design Group, to develop a better understanding of high entropy alloys like those used in his project. Next, he wants to determine which of the alloys that most effectively kill pathogens can be manufactured in bulk. Additionally, Gilbert is generating a proposal for NSF based on the preliminary findings from this work.

Subhadeep ChakrabortyDriver inattention is the leading cause of traffic accidents in the U.S., resulting in thousands of deaths per year. Inattention can be the result of driver fatigue, texting, loud music, or even daydreaming. Whatever the cause, when a driver’s focus strays, lives are put at risk. Associate Professor of Mechanical, Aerospace, and Biomedical Engineering Subhadeep Chakraborty’s work with biometric sensing could help minimize that risk. 

Biometric sensing is the process of gathering information about a human, in this case the driver of a vehicle, such as where they are looking or their heartrate. Data gathered from a driver can subsequently be cross referenced with information about the vehicle itself and its surroundings to assess the situation and determine if the driver is behaving normally.  

“Our physiological responses are tied to what the vehicle is doing and what is going on around the vehicle at the same time,” said Chakraborty. “Looking at these three things simultaneously will allow us to determine if a driver’s behavior is normal or something that could become dangerous. We can then act upon that by sounding an alarm for a sleepy driver or vibrating the steering wheel to return a distracted driver’s attention to the road.”  

He cautions that for this technology to be effective, it must be accurate enough to avoid regular false alarms. Chakraborty’s team has developed a headmount containing a series of sensors capable of collecting biometric data as well as information about a driver’s gaze. The next step is to integrate that headmount with a driving simulator and begin building a data set, which will use both UT and ORNL equipment. 

“Our lab setup is drawn from high-end gaming systems and uses a head mounted display. We can control the environment and get immediate data from the simulations. We can use this to gather driving data and safely simulate distractions by asking participants to solve puzzles or play memory games,” said Chakraborty.  

From there, his team hopes to also gather data via a state-of-the-art simulator located in ORNL’s Connected and Autonomous Vehicle Environment (CAVE) Laboratory. This simulator mimics the experience of driving by removing a vehicle’s wheels and mounting the hub directly to four dynamometers. The full steering capability with torque feedback based on the current simulated vehicle dynamics make the simulation feel more realistic. This could translate to more accurate biometric data and fewer false alarms for potentially distracted drivers.  

Chakraborty was previously the recipient of Science Alliance funding for his work on connected vehicle technology. That work involved several cross-disciplinary collaborations on campus that now, in addition to being applied to his StART project, have created opportunities for approaching his work from a holistic perspective.  

“I don’t think these kinds of projects have any boundaries anymore. It’s a mechanical engineering topic, it’s a computer science topic, it’s a civil engineering topic,” said Chakraborty. “Ultimately, we are trying to address a safety issue, and that issue is multi-dimensional and needs to be looked at from a variety of perspectives. Fortunately, we have built a community capable of doing that.” 

Francisco BarreraNeuromorphic computing is the use of the human brain as design inspiration for computer systems, and has been steadily gaining interest since the 1980’s. Its potential to improve both speed and energy efficiency in computing, and subsequently supercomputing, make neuromorphic computing a thriving area of interest. 

While not attempting to directly copy the human brain, neuromorphic computing draws inspiration from neurons and synapses to develop new means of computation and information transfer. Innovation is an important part of the field of neuromorphic computing, and Francisco Barrera, associate professor of Biochemistry & Cellular and Molecular Biology, is bringing a new approach to chip development. 

Historically Barrera’s work has focused on the plasma membrane, a protective barrier between individual cells and their external environments, which also regulate cell signaling or communication between cells. For this StART project, Barrera is using his expertise in collaboration with Pat Collier, staff researcher at ORNL.  

“The Collier laboratory is working to recreate how neurons work using a system called droplet interface bilayer,” said Barrera. In a droplet interface bilayer, DIB, system there are small membranes that closely mimic the membranes of neurons. When connected, these membranes have been shown to do some promising computing. 

Barrera’s team’s work could improve the function and connectivity of these membranes. They have designed a peptide that, when added into the membranes, canb change how currents move across the membranes, which is important for communication.  

“What I think is very exciting is that I believe we can make an important contribution, because we try to understand, at a very deep level, how our peptides interact with lipids in the membrane,” said Barrera. “This is the kind of basic knowledge that allows you to understand a system and predict how it will respond.” 

Barrera hopes the discoveries made with this StART project will ultimately lead to increased power and flexibility in chips for neuromorphic computing. 

Sindhu JagadammaCarbon is the foundation of all life on planet Earth and is a central component of climate, food production, and energy creation. Carbon cycling is the way carbon is recycled or moved around from the atmosphere, into organisms and soil, and back out again. Changes to each of these components have the ability to impact the carbon cycle, but the potential effects of soil composition are not well understood. Assistant Professor of Biosystems Engineering and Soil Science Sindhu Jagadamma hopes to improve that understanding. 

Plants pull carbon dioxide from the air and, through photosynthesis, convert it to plant biomass, which ultimately ends up in soil as soil carbon. Soil carbon is critical to sustainable food production, playing a vital role in soil, water and air quality. Securely storing carbon in soil is also important for reducing the concentration of carbon dioxide in the atmosphere.   

Soil composition plays an important role in soil carbon cycling. For example, manganese content in soil can impact carbon cycling by influencing photosynthesis and litter decomposition. Jagadamma’s StART project is focusing on the impact of manganese on the balance of carbon within agricultural soil systems. 

“It is really important to understand the different drivers of carbon cycling in soil in order to build healthy soils and promote sustainability,” said Jagadamma. “The role of manganese in influencing carbon decomposition is relatively unknown, especially in agricultural soils.” 

Jagadamma points out that nitrogen fertilizers may create more acidic soil, which increases manganese availability. While manganese is an essential nutrient for plants, excess manganese in soil can inhibit plant growth and lead to lower crop yields. However, a comprehensive study determining the link between manganese, carbon cycling, and the impact on crop lands has yet to be completed. 

Jagadamma’s ORNL collaborator, Staff Scientist in Environmental Sciences Elizabeth Herndon, has begun this work with laboratory and field experiments in forested ecosystems. The knowledge these experiments have generated is being used by Jagadamma’s team to extend the research into the agricultural field.  

“We are going to manipulate different levels of manganese in soil, grow plants, and see if the different levels of manganese are influencing plant growth and litter decomposition, and how it is ultimately going to influence the carbon cycle,” said Jagadamma.  

Her project, like so many others this year, was delayed due to COVID-19 precautions but she hopes to move into the experimental phase next spring. In the meantime, she and her team have focused on literature review and a lab-scale pilot study to assist in developing the most meaningful field experiment for the Spring. 

Jagadamma’s StART project will have obvious implications for agriculture. If soil manganese is altered by nitrogen fertilization and other human-induced changes, and if those altered manganese levels change soil carbon storage, cropland systems can be developed for better crop growth and carbon storage. This work will also have broader implications for global carbon cycling by helping to curb carbon dioxide levels in the atmosphere. 

Hugh MedalThe Materials Genome Initiative, MGI, was announced in 2011 as a multi-agency initiative intended to increase the speed of advanced materials development and production. Since that time the federal government has invested more than $250 million in new research and innovation infrastructures to help achieve that goal. Assistant Professor of Industrial and Systems Engineering Hugh Medal hopes his StART project will also contribute to the goals of the MGI. 

The Materials Project was announced as a key program of the MGI with the goal of providing open access to a registry of known and predicted materials. Since it’s inception, the Materials Project has amassed a database of hundreds of thousands of materials with their predicted properties, information that would normally require repeated experimentation to discover. 

However, knowing the material can exist is not the same thing as successfully creating it. While the simulations contributed to the Materials Project may be able to point toward potential new materials, figuring out how best to grow those materials is left to experimentation. 

“Making a material is a lot more complicated than just putting components together,” said Medal. “Think about steel. It’s not just a matter of adding different elements from the periodic table. It requires applying a lot of different processing actions in order to get the material to its final state, or phase.” 

The question of how best to develop these predicted materials is a large one in material science. Medal is attempting to make inroads of this problem with his StART project. His team in collaborating with Haixuan Xu, associate professor of materials science and engineering and former Science Alliance JDRD awardee, to create a simulation to predict how to grow these materials. 

“We’re working together to come up with a technique that can tell us how, given a predicted material that’s really interesting, what processing do we need to apply over time to be able to grow that material,” said Medal. 

Leveraging Xu’s expertise in modeling the kinetic behavior of materials and Medal’s work with machine learning, the team hopes to develop a tool to serve as a guide for experimentalists as they work toward creating predicted materials. 

“Our hope is that our tool that will simplify the process. Rather than having experimentalists sift through a large number of combinations of processing actions, we want our tool to point toward the processes that would most likely be successful,” said Medal.