Nanostructures and Lego® Bricks

Ludovico Cademartiri (right foreground), assistant professor of materials science and engineering, and his research team use an interdisciplinary approach to tackle a wide range of challenges in materials science
Ludovico Cademartiri (right foreground), assistant professor of materials science and engineering, and his research team use an interdisciplinary approach to tackle a wide range of challenges in materials science

Advancing technology through practical and radical materials science

Materials science, chemistry, physics and life. These are the driving forces behind the research in Ludovico Cademartiri’s laboratory at Iowa State.

Cademartiri, assistant professor of materials science and engineering and associate scientist with the U.S. Department of Energy Ames Laboratory, says he and his graduate students work to go beyond understanding materials to exploring what’s happening at the edge of the discipline.

“The general approach of our lab is that we try to use our skills at making materials to answer fundamental questions, whether they are related to materials science, another discipline, or some space between,” Cademartiri explains.

The result is a good mix of interesting scientific problems, each with its own potential.

One project involves a big breakthrough but is also facing significant experimental challenges. The group wants to create a ceramic that behaves like a plastic. Combining the properties of these two classes of materials typically requires mixing them together in composites, which are difficult to process. No single material combines the properties of ceramics and plastics. Cademartiri says that while it’s considered fundamentally impossible, the group has evidence to the contrary.

“We’ve seen similarities between plastics and crystals when crystals are very thin, 50 thousand times thinner than a human hair. Plastics are composed of an entangled mess of thin strands, molecules specifically. These strands are very flexible in plastics, which allows them to behave the way they do. We have clear evidence that some extremely thin crystal strands are similarly flexible. Determining exactly how similar they are is important to apply these materials but is also extremely challenging.”

In another research program, the group has made significant headway in controlling microstructures in ceramics. The team has helped resolve an issue that had previously prevented making materials by selecting their individual components and then assembling and processing those components to create a material.

Cademartiri says in the past building a material from the bottom up has resulted in the material disintegrating during processing, making it hard to apply in devices. His team has found a new approach to avoid this issue entirely, thereby enabling an entirely new way of manufacturing materials with nearly complete control over their composition and structure. The findings will be published soon in two back-to-back articles in the journal Advanced Materials.

In a less traditional project, Cademartiri’s team has been working to use LEGO® bricks to simulate an ecosystem in the lab to study how plants interact with their environment. “We can control and understand pretty well a plant in isolation, but there’s so much more involved when you include the ecosystem wherein the plant exists,” he says. “If we can simulate this environment, and understand and predict how plants will respond to it, we should be able to improve the reliability of our food supply.”

While the group’s overall focus is to provide solutions for global problems (like improving food supply) and to resolve issues at the foundation of modern materials engineering (such as programming material properties, replacing extremely rare elements in materials, translating materials and processes from the lab to the outside world, and understanding what happens at the interface of two materials), Cademartiri says he encourages his team to think outside the box.

“Materials are, in most cases, the bottleneck in the development of new technology and new solutions,” he says. “Therefore, controlling materials or, in other words, knowing how to build things atom-by-atom, is one of the safest ways to have an impact on the world.”

Engineering better health

Surya Mallapragada, Carol Vohs Johnson Chair in Chemical and Biological Engineering
Surya Mallapragada, Carol Vohs Johnson Chair in Chemical and Biological Engineering

Polymeric biomaterials combined with nanoscale delivery devices can improve preventative medicine

Surya Mallapragada knows the value an engineering perspective can add to advancing the biomedical field.

For years, Mallapragada, the Carol Vohs Johnson Chair in Chemical and Biological Engineering, has been researching the best ways to synthesize copolymers and nanoscale delivery devices to treat illnesses. Now, she’s looking at ways to prevent disease.

“When we were focused on treatment technologies, we wanted to minimize the immune response to the drugs that were being delivered to a patient, creating an environment that would allow the medicine to be effective in fighting against a disease,” she explains.

Shifting her focus to preventative medicine like vaccines, Mallapragada says her team wants to maximize immune responses to different drugs so the patient is protected against a variety of diseases and stays healthy. “We have a good understanding of which chemistries will elicit the right response given the different applications,” she adds.

That information is being put to use within nanoscale drug-delivery devices Mallapragada’s team is designing. Her group is focusing on vaccines that carry just the proteins or DNA from pathogens, a change from traditional vaccines that have been created using live, or attenuated, pathogens.

“When we use attenuated pathogens, we have to consider a number of factors, including growing a virus somewhere like chicken eggs and transporting and storing the virus,” she says. “Since our work is using only part of a pathogen in a nanoscale delivery device made of a polymer, we can design materials that are more robust without having to worry about the disadvantages of working with live viruses.”

Mallapragada’s work is part of the polymers and materials research going on within the Nanovaccine Initiative at Iowa State. The initiative includes several researchers who are developing nanoparticle platforms that can be used in disease prevention.

“The platform technologies we are creating aren’t necessarily disease specific. It’s a bigger picture plan to improve both the effectiveness and accessibility of vaccines,” Mallapragada adds. One example would be having a team look at using proteins or pieces of pathogens to create a combination vaccine that fights both influenza and pneumonia since those diseases can often occur together.

The projects involve interdisciplinary teams that include researchers and medical professionals both on and off campus. “Immunologists are learning about materials science, and students and post docs in engineering are learning about cell cultures and animal models,” Mallapragada says. “The collaborative environment has allowed us to thrive, and we’re looking forward to seeing these projects eventually head to human clinical trials.”

ATHENA Lab augments human capabilities

Tom Schnieders and Rick Stone
Tom Schnieders (left) and Richard Stone

Engineering ideas and technologies enhance human performance, preserve safety and quality of life

Developing telerobotics control systems, applying biomechanics for improved sports performance, creating visualization tools that improve battle space awareness. These projects and more are going on within the Augmentation and Training of Humans with Engineering in North America Lab.

The lab, known as ATHENA Lab for short, is one of four labs of its kind in the world. And the only one the Augmented Human International Conference Series recognizes in North America.

“We want to make humans more capable and safer, and we’re using a mix of ergonomics, augmented reality and cutting-edge technologies to accomplish our goals,” says Richard Stone, an associate professor of industrial and manufacturing systems engineering, co-director and co-founder of the lab.

The ATHENA Lab evolved from the Human Performance and Cognitive Engineering Lab that Stone started when he came to Iowa State in fall 2008. Fast forward to 2015 and bring in Thomas Schnieders, a Ph.D. student in industrial engineering and the other co-director and co-founder of the lab, who talked with Stone about the potential of having a recognized human augmentation lab on campus.

“The ATHENA Lab takes what we were already doing and gives us more focus. It also shows us other areas where we could be adding value with our work,” explains Schnieders. “A lot of labs do great work individually in biomechanical, biomedical and cognitive science, but our lab tries to merge all these aspects to see how they work together.”

No two days at the ATHENA Lab are similar. The researchers are constantly running new experiments, testing body armor one day and the next they might be focused on figuring out what technologies could make wound suturing more consistent.

“Our setup is always changing, and we’re moving equipment around all the time,” Stone adds. “At any time you might see boxes of basketball shoes stacked to the ceiling or maybe robots tucked away on a shelf. It just depends on what problem we are working to solve.”

The ATHENA Lab is also equipped with a large variety of sensors, cameras, hardware and software the researchers use to gather data.

Stone says the students who work in the lab bring a lot of energy and excitement to the projects. “The work we are doing is very focused. They get to work on projects they can apply to their everyday life, and they get to see the end results of their time and effort,” he explains. “It’s fun to see young students come in and show them a different side of engineering.”

Leadership in multiphase flow discovery, education and practice

Multiphase flow scienceA cohesive group of researchers at Iowa State has joined together to accelerate discoveries in multiphase flow science and their transfer to industry.

The group known as CoMFRE initially started out in 2002 as an informal way for faculty to share insights about related research projects. Now, the team is more formally organized with a mission to bring ideas together to make computational and experimental multiphase flow research more cohesive and connected.

Shankar Subramaniam, professor of mechanical engineering, and Rodney Fox, distinguished professor in chemical and biological engineering, lead the group of 18 faculty members who make up CoMFRE. The group also collaborates with a number of experts in industry, academia and national laboratories.

Subramaniam says having a large number of faculty and experts involved has helped the group expand its impact. “We aren’t working on just one problem. We’re working on a set of techniques that can be rapidly realigned to various problems. I anticipate that over the next 20-25 years we can continuously reinvent ourselves to solve whatever the hard multiphase flow problem of the day happens to be.”

One major initiative within CoMFRE is biofuels. As biomass, such as corn stover, is heated to create fuel, multiphase flow researchers can analyze how changes in the composition of biomass and flow impact the reaction.

The team develops simulations of biomass reactors, analyzes computational data gathered during the process, and evaluates the economics of the facilities used to generate biomass and biofuels, effectively performing an entire life-cycle analysis that focuses on efficiency and sustainability.

“From a computational perspective, all of our work involves a variety of statistical and mathematical methods and visualization,” Subramaniam says. “While it’s relatively easy to compute large amounts of data, we take our research beyond information. We provide insight into the processes occurring and look for answers to research questions.”

As the long-term applications and science research being developed under the umbrella of CoMFRE continues to grow, Subramaniam says the group’s industry outreach will also expand. CoMFRE facilitates training, seminar and networking opportunities for industry collaborators, where the group shares rich knowledge and diverse expertise to advance research in the multiphase flow field.

Collaborators come from a variety of industries including energy, healthcare, materials design, advanced manufacturing, sustainability and infrastructure.

The team also incorporates training and workforce development for graduate students, providing them with skills that can be applied across industries to investigate multiple challenges. CoMFRE is even proposing to break away from the traditional Ph.D. structure to act as more of a learning community, where graduate students work with peer groups and a whole group of faculty members acting as advisers. In addition to refining their technical skills, the students will be trained on entrepreneurship, which would prepare them to adapt to changes that can occur in the research landscape over time.

“We want our graduates to be cognizant of how to connect their work to societal issues,” Subramaniam says. “We think we’ve set up CoMFRE to prepare these students to be industry leaders while we also make advancements in our research.”

New heights for materials science

With his plans to develop an open-source manufacturing platform, Peter Collins is determined to make additive manufacturing a mainstream technology.

Collins, who is an associate professor in materials science and engineering, says the advantages of additive manufacturing—using fewer resources, improving material performance and creating one-of-a-kind products—can be a game changer for manufacturers of all sizes.

nanoscale materialsThat’s why he’s working on a program that will reduce the amount of testing involved with the additive manufacturing process.

“When we look at creating a better material, additive manufacturing is a great place to start,” he explains. “Rather than taking a huge piece of material and sizing it down to fit within the parameters we have, researchers add small amounts of powder to specific areas of a material to achieve desired characteristics and geometries. It’s simply a more efficient and effective approach.”

Collins wants to tailor materials to exact specifications, such as designing high strength on one side of the material and high stiffness on the opposite side. He says being able to change composition of a material is useful for many industries, including energy, aerospace and automobile markets.

But testing materials created through additive manufacturing is a significant investment and a big part of why the process isn’t commercially available. “Manufacturers spend sizable amounts of money to create a large piece of material, then section it into smaller pieces to send off for mechanical, fatigue and composition tests,” Collins says. “As you can imagine, it’s expensive, and if something doesn’t meet the desired performance, you have to create a new piece of material and do it all over again.”

Material characterization, which involves looking at how the atoms and crystals in the material are arranged, can help researchers predict the composition of a material and reduce the expenses associated with testing. “Knowing how materials will respond after they go through specific processes will help us understand what elements we will lose and what characteristics the material we’ve developed will exhibit.”

A large part of his research with groups such as the Defense Advanced Research Projects Agency, National Science Foundation and the Boeing Company focuses on bringing this materials science mindset into additive manufacturing.

He also wants to reduce costs associated with additive manufacturing, which accumulate thanks to the equipment, like lasers and electron beams, used in the process. So he’s developing an open-source manufacturing platform with visions that every town could implement additive manufacturing. “Something like this would mean a farmer could go into town and repair or create a new piece of equipment instead of paying an exorbitant amount to have one made and shipped to them,” he explains.

While he knows there’s a lot of research that needs to be done before this vision becomes reality, he says his approach is definitely a step in the right direction.

“Adding material characterization to the process gives us the information necessary for exploring and creating superior materials for the manufacturing industry much quicker than has been done in the past.”

More data, more vulnerabilities

Protecting and securing data takes on many forms at Iowa State, where researchers in electrical and computer engineering are tackling big threats in the digital world: detecting malware on apps, improving online privacy and eliminating insider threats.

Mathematical abstraction and software reasoning

Suraj Kothari, Richardson Professor of Electrical and Computer Engineering, mixes theoretical ideas and practical application together as he looks for ways to improve the quality and security of software. The tools he has developed utilize visual mathematical models to dissect and conquer larger problems.

Recently, his models have been applied to detecting malware attacks within mobile applications for a Defense Advanced Research Projects Agency project. Kothari’s team designed a tool that gathered important information about an app as it scanned code for malware. This data is then presented in a compact form for a human analyst to review, allowing for more accurate assessments about an app’s intentions than systems currently in place. The tool is flexible enough to be refined and extended to address future malware attacks.

Machine learning to secure information

Morris Chang, associate professor of electrical and computer engineering, wants to make sure data collected by third-parties (think: healthcare workers or employers performing background checks) stays private. He says individuals providing personal information are increasingly exposed to vulnerabilities that may exist within a third-party’s data-collection system.

Through DARPA’s “Brandeis” Program, Chang is creating technology that helps secure privacy over the Internet through distributed algorithms that protect user’s data on mobile devices. Chang’s approach focuses on securing data before it is transmitted via Internet to remote cloud services. These services then use machine learning techniques to process data, allowing the data to be transferred in an irreversible way before reaching the Internet.

The project brings together researchers from several universities and segments the work to propose a solution to addresses the efficiency, privacy, security and flexibility of Internet computation.

Parsing big data to identify threats

Srikanta Tirthapura, associate professor of computer engineering, makes big data more manageable with methods that analyze extremely large data sets, especially data that quickly changes, which are often referred to as data streams.

Part of Tirthapura’s research is applied to cyber security, where he looks at how to convert, store and analyze information to find anomalous user behavior or unauthorized access. One example is insider threat detection, where someone within an organization who has authorized access to some parts of the system misuses his or her access.

He says detecting insider threats adds an extra challenge because the user is familiar with the system. In this case, technology is essential to search through gigabytes of files to identify unusual behaviors. That’s why Tirthapura has created tools that can be used across a variety of datasets and problems to efficiently retrieve and process information.

Engineers, elementary educators and future teachers partner to teach STEM

TrinectAt Iowa State, integrating engineering into K-12 classrooms is a collaborative effort that spans across campus and into surrounding school districts. Trinect, a program funded by the National Science Foundation STEM-C Partnerships, brings together three groups to introduce engineering concepts to young students: engineering graduate students, preservice teacher students and cooperating elementary teachers from Des Moines Public Schools.

“Trinect is about sharing knowledge and helping elementary teachers gain confidence in teaching STEM subjects,” says Adah Leshem, pre-college education program director at the NSF Engineering Research Center for Biorenewable Chemicals located on Iowa State’s campus. Leshem is Trinect’s project co-director and was a driving factor in establishing the program.

“We know there’s a crucial timeframe for engaging young students in STEM fields and there’s often a lack of opportunity for students to experience these subjects. We think Trinect can help fill those gaps.”

Each semester, 10 Trinect Fellows, who are engineering graduate students, work with 3rd-5th grade students and their teachers. The fellows help teachers understand the concepts of the engineering  design process as well as reaffirm common subjects such as math, science and technology.

“Instead of having graduate fellows teach the concepts, they act as a resource for teachers and students. The approach engages teachers as they develop innovative activities focused on STEM subjects,” Leshem explains.

Iowa State’s School of Education’s preservice teachers represent the third partner of Trinect. These students are placed in cooperating teacher classrooms for 16 weeks and participate in teaching STEM concepts. At the end of the program, they are better prepared to independently integrate these types of lessons into their own classrooms once they are in the workforce.

Leshem says an external partner will measure the overall effectiveness of Trinect. The data will evaluate how the triad functions as a team and how the approach the program is using compares to traditional learning methods.

“We’ll be continually improving our program as we receive feedback and looking for additional opportunities to expand collaborations,” Leshem says.

Market-ready solutions

Matt Darr
Matthew Darr, associate professor in agricultural and biosystems engineering

Advanced ag machinery technology developed at ISU transfers to industry

Matthew Darr’s research group strives to make an impact that extends knowledge and scientific development to the marketplace. “Seeing our results ported out to the public sector where we’re able to help agricultural producers with intelligent technologies — that’s our ‘why,’” he says.

Darr, an associate professor in agricultural and biosystems engineering, runs an industry-focused research program at Iowa State, working on innovations in the agricultural equipment and agricultural automation sectors.

“We’ve developed strong relationships with industry partners, which helps us better understand their needs. We then focus our research on addressing applied research questions through targeted applications of advanced technology, science and innovation,” he says.

Much of the group’s work is data driven, with researchers working to both collect and analyze complex data from a range of agricultural systems. Darr says analysis of vehicle sensor networks has become a focal point for the group’s research.

The team develops algorithms for sensors used within agricultural equipment for a range of purposes and then works with industry partners to get that intelligence integrated into a commercial product.

Because the agricultural field relies heavily on telematics to gather data, Darr’s group creates hardware and software solutions that integrate the process. One such project involved assessing the logistics behind cellulosic ethanol supply chains in the Midwest. Industry partners used technology from Darr’s team to gather data and then made informed changes to how the plants operate, saving time and money.

Another area Darr is exploring is unmanned aerial vehicles, which involves remote sensing with UAVs. “We are utilizing this technology to acquire plant health indicators for individual plants.  This allows us to create a quality index that is used to adapt farming operations and make decisions related to crop production,” he explains. “The data from these UAVs can help producers make decisions about everything from water management to fertilizer application.”

While most of the group’s work has a significant impact in the Midwest, Darr says there’s an international component to the team. Test research of the group’s technologies happens on four continents every year, something Darr says provides the group with a greater understanding of how technology could help in the less developed ag markets.

The team’s successful approach in partnering with industry to create transferrable technology is an accomplishment in and of itself. Thanks to Iowa State’s land-grant mission, the university has flexible options for industry partners that address intellectual property concerns and facilitate the process for all parties involved.

He adds that diversity in the research group, which includes computer scientists, researchers from a number of engineering disciplines, ag technologists and students, gives the team a broad perspective for approaching problems.

The team’s work recently contributed to three innovation Silver Medal awards at AGRITECHNICA 2015, a global showcase of ag machinery in Hannover, Germany. The award-winning innovations, which were developed at Iowa State University and licensed to John Deere, involved the operation of harvesting equipment.

“When we see the value our work creates for producers, we know we’re making contributions to the agricultural industry,” Darr says. “Iowa State creates an environment where this is possible, and we are able to make a difference because of it.”

Power management in smart robots

Ran Dai and student team
Ran Dai, foreground, an assistant professor in aerospace engineering and Black and Veatch Faculty Fellow is working to develop technologies that will help robots manage their energy use to improve efficiency and battery life

Designing solar-powered vehicles for long-duration, high-efficiency missions

Using renewable energy to power aerial and ground vehicles could change the way we handle aspects of environmental monitoring, search and rescue missions, surveillance, and agricultural practices.

To navigate these sorts of dynamic environments, Ran Dai, an assistant professor in aerospace engineering and Black and Veatch Faculty Fellow, says a solar-powered robotic system offers a lot of promise.

During her first year at Iowa State, she and undergraduate research assistants manufactured the first prototype of a solar-powered ground vehicle in her Automation and Optimization Laboratory.

The vehicle was capable of designing an efficient path to harvest energy from the environment while simultaneously allocating its available power among electric components. The team also created an indoor solar simulator to have a static environment for evaluating the robot’s performance.

Now, confident her ideas will work, Dai has moved forward with a second- and third-generation robot, adding real-time power tracking to record the vehicle’s power intake and consumption, along with a solar-powered unmanned aerial vehicle.

The project is supported by a $500,000 grant provided by the National Science Foundation’s CAREER program, which is designed to support the research and teaching of junior faculty, and will expand the usefulness of these unmanned vehicles even more with advancements that will improve their endurance and capability.

Dai says her biggest obstacle in this work is the weather. “Our algorithms can help the robot make decisions based on available solar energy, but if it’s cloudy, the robot could go into sleep mode to conserve energy, resulting in a delay in completing a mission.”

She says those sorts of delays could be offset with cooperative, back-up vehicles that harvest energy while the other robots are doing work. When the working robots need to recharge, the second group could step in to realize a persistent operation.

“The key to being able to make a system like this work is to find out how to make a robot energy-aware and autonomous,” she says. “That way it could recognize changing solar conditions and make necessary adjustments.”

Dai also plans to develop an open-source software program everyone can use. She hopes this will lead people who are interested in the technology to create their own solar-powered robots.

In the end, it’s the big picture that drives Dai forward — she wants to contribute to the country’s economic vitality, public health and security with these robots.

Soil and water samples illuminate antibiotic resistance

Michelle SoupirStudies of manure application reveal antibiotic resistance movement

While using manure as an organic source of fertilizer has helped the agricultural industry maintain balance in integrated crop and livestock systems, there is some risk the manure contains bacteria that may contaminate water bodies if transported off the field by rain.

Michelle Soupir, an associate professor in the Department of Agricultural and Biosystems Engineering, and her team of researchers are examining the transport of two pathogen indicators: E. coli and enterococci. Both are identified by the EPA as indicators of potential fecal contamination of water resources. She also looks for relationships between the traditional pathogen indicators and antibiotic resistance.

Soupir says identifying the resistance is incredibly difficult. “When you monitor environmental systems, you can be on a fishing trip of sorts when determining what resistance might be out in the environment. In our study, we targeted tetracycline and tylosin.” Both are antibiotics. Tetracycline treats bacterial infections like acne and genital or urinary infections, whereas tylosin isn’t prescribed to humans but is in the same class as other common human antibiotics like erythromycin.

The fieldwork is conducted at the North East Iowa Research Farm (NERF), near Nashua, Iowa. A different land-use treatment is applied to one-acre plots of crops, separated from other plots by berms and curtain drains to reduce cross-contamination from either above or below the surface. Manure is injected into some of the plots in bands close to the root system before the first hard frost.

“It’s applied in the fall so ammonia doesn’t volatilize, and we don’t lose the nitrogen we’re applying,” says Soupir. “It’s always a gamble, because you want to do it right before the soil freezes.” The manure is then held in the soil all winter at cold temperatures, which is a benefit to water quality as the cold temperatures tend to kill off some of the pathogens and resistant bacteria.

The team is getting data from three points in the system. Samples of the manure that is applied to specific plots tells them how much antibiotic resistant bacteria and pathogen indicators are going onto the plots. Measurements of the soil show how long the organisms survive. This leads the research team to take samples of water, which tells them what organisms are moving off site and could potentially be moving into surface water.

But the results of this have not been as expected. “We rarely see statistically significant differences between the manure amended and control plots in the tile drainage water,” says Soupir. “It’s been surprising that there aren’t more statistical differences. For the most part, it’s been pretty good news for pork producers because the method of manure application (injection in the fall) seems to be a good management strategy for preventing pathogens and resistant bacteria from moving into the tile drains.”

The project is on its fourth year, and while most of the results are on swine manure, the researchers have begun to look at a poultry-amended site as well as a beef-amended site. Soupir says these research sites are novel because they have received manure application for long periods of time. “It’s really made me appreciate the need for long-term studies.”

Materials under extreme conditions

Illustration of a sample being compressed and sheared in a rotational diamond anvil cell
Illustration of a sample being compressed and sheared in a rotational diamond anvil cell

Search for new materials and phases under high pressure and large plastic shear

When you look at the properties and strength of a diamond, which is created under intense heating and pressure, it’s clear there’s value in understanding how it’s synthesized. Phase transformations under high pressure, like when graphite is formed into a diamond, are at the heart of the theoretical work Valery Levitas has been conducting throughout his extensive international career.

Levitas, Iowa State’s Schafer Professor and faculty member of aerospace engineering and of mechanical engineering, conducts fundamental research to predict and discover new phases of materials under high pressure. His work can be translated into engineering applications, including synthesizing superior materials for new technologies and products.

A significant part of his research investigates ways to retain high-pressure phases after pressure is released. To do this, he uses plastic shear, or an irreversible deformation that is applied with a rotational diamond anvil cell (DAC). He explains that plastic deformation not only changes the shape of a sample, it also changes the sample’s microstructure and generates new defects and phase transformations.

More importantly, the shear drastically decreases the pressure necessary to create desired phase transformations. “Near the defects we create, there are regions with concentrations of large stresses, which can be considered as pressures in different directions,” he says. “Instead of applying external high pressure, we apply a lower value of pressure coupled with large plastic shear to generate new defects.”

Using a rotational DAC in place of a traditional DAC has required Levitas to develop a new multiscale theory to explain the interactions between phase transformations and plastic flow under pressure. He says this is because unlike traditional high-pressure physics, which operates with the single parameter of pressure, he has to understand the effect of six components of stresses and six components of plastic strains, as well as the effect of evolving defects.

The corresponding analytical and computational approaches he developed to support his theory explain mechanisms of strain-induced phase transformations at the nanoscale as well as the complex behavior of a sample in rotational DAC.

His research group has been able to predict and confirm new phenomena through experiments. Notably, the team has proven the possibility to reduce transformation pressure by an order of magnitude to transform boron nitride from graphite-like to superhard, which may serve as a precursor of new technologies. Experiments have also revealed a new amorphous phase of silicon carbide that may shed a light on how armor ceramics are damaged under projectile penetration.

Levitas began his work in Kiev, Ukraine, and brought his high-pressure theories and technology to the U.S. in 1999. It took him eight years to obtain his first federal grant on this topic from the Defense Threat Reduction Agency, but now this work is supported by the Defense Advanced Research Projects Agency, National Science Foundation and Army Research Office.

“As the only team in the world working on this topic theoretically and the only one in the U.S. performing experiments with rotational DAC, I’m encouraged to see interest growing,” Levitas says. “Having an understanding of materials, including how they behave in natural and technological processes like earthquakes, friction and wear, surface treatment, military applications, and mechanochemical processes like ball milling, will lead to ways of controlling these processes and creating even greater materials.”