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Former JDRD Faculty Receive Federal Career Awards

   David Donovan

This month, two faculty members in the Tickle College of Engineering were the recipients of Early Career Awards from the Department of Energy.

Assistant professors Haixuan Xu and David Donovan, both previous participants in the Science Alliance JDRD program, will receive $750,000 over the course of 5 years to fund their research.

Xu’s research focuses on structural materials for nuclear energies, while Donovan’s work is in the area of nuclear fusion. The grants will also help to support graduate students and post-docs working with the faculty members.

Professor Developing Device to Administer Cancer Drug

A new device under development by a nuclear engineering professor will allow doctors to dispense accurate dosages of a drug made with actinium-225, an isotope that has been shown to be effective in treating—and curing—myeloid leukemia.

Eric Lukosi

The device, devised by Assistant Professor Eric Lukosi and fabricated by master’s student William Gerding, is currently in production. Once it is built, it will go through testing at Oak Ridge National Laboratory.

“We’re slowly moving toward the demonstration of the device. It’s been fabricated; now we just need to package it and make sure it works,” Lukosi said. “This could help save lives.”

Lukosi’s device would act as a critical quality assurance measure, guaranteeing that patients receive treatments exactly as recommended by their physicians.

Myeloid leukemia can spread quickly and affect lymph nodes, organs, and the central nervous system. Acute myeloid leukemia is found most often in adults over the age of 45 and is frequently fatal for patients 60 and older.

Actinium-225 is an isotope extracted from thorium-229, a waste byproduct of the fuel that was used for ORNL’s molten salt reactor experiment in the 1960s. In 1994, ORNL began purifying thorium-229 in order to extract actinium-225.

Since then, ORNL has sent approximately 900 shipments of actinium-225 to hospitals, clinics, and research institutions. The isotope has been studied as a treatment for cancer for a number of years and recently gained attention as a possible cure for myeloid leukemia.

As with many medical treatments, particularly radiation therapies, quality control issues that could jeopardize patient health are a concern. Support technologies play an important role in ensuring patient safety. For example, modern insulin pumps assist in diabetes treatment by monitoring blood sugar levels so appropriate levels of insulin can be delivered to a patient throughout the day.

Actinium-based therapies could specifically benefit from support technology because current control methods can be time-consuming and costly.

“Right now, the method of finding out what is inside the sample requires an external detector,” Lukosi said. “There are a lot of factors that need to be taken into account to get an accurate measurement of the activity inside the sample.”

Initially, Lukosi conceived of the device to use in spent nuclear fuel reprocessing.

“There are a whole host of applications for this technology, including environmental sampling,” he said.

CONTACT:

Megan Boehnke (mboehnke@utk.edu, 865-974-3242)

Jennifer Brown (jbrow209@utk.edu, 865-974-6765)

Distinguished Scientist Robert Hatcher Retires

After 32 years of service Professor of Geology and Distinguished Scientist Robert D. Hatcher, Jr retires at the end of June, 2018.

Hatcher first came to the University of Tennessee, Knoxville in pursuit of his doctoral degree, after earning bachelor’s and master’s degrees from Vanderbilt University. Born in Madison, TN, Hatcher completed his doctoral program in 1965 and left Knoxville for approximately 20 years.

Moving around the southeastern U.S., he taught at Clemson University, Florida State University, and the University of South Carolina. In 1986, he was invited to return to the University of Tennessee.

“At first I said no,” said Hatcher, speaking at a retirement event in his honor. “I didn’t think you should teach where you went to school, but they convinced me to change my mind.”

Fortunately for the university, he returned to Knoxville and became one of the earliest Distinguished Scientist appointees with the Science Alliance. Since that time, Hatcher has mentored 52 master’s students and 17 doctoral students, and taught thousands of hours of classes.

Over the course of his career, he has served in a variety of leadership roles within his field. He was president of the Geological Society of America from 1992 to 1993 and president of the American Geological Institute from 1995 to 1996. He was awarded the first ever Geological Society of America Distinguished Service Award. In 2014 he received the American Geosciences Institute’s Legendary Geoscientist Medal.

“Every time I go to a conference, almost everyone I speak to asks if I know Bob Hatcher,” said Michael McKinney, department head and professor in the Department of Earth and Planetary Sciences. “The further he got in his career, the more productive he seemed to get.”

Michael McKinney presents Robert Hatcher with a plaque from the Department of Earth and Planetary SciencesAt the retirement celebration, McKinney presented Hatcher with a plaque commemorating his years of service to the university and the State of Tennessee. The department also gave Hatcher a large piece of Tennessee marble with a metal tag reading “In honor of a lifetime of major achievements, service, and contributions to science. With gratitude from thousands of colleagues and students whose lives you have touched.”

Perfecting Defects Could Impact Semiconductors

Haixuan XuIn baking, cooks often start with a simple recipe of flour, baking powder, butter, sugar, and eggs. This basic list of ingredients will come together to make a base for a variety of different goods. From here, the addition of milk will turn that base into cake batter, while baking soda will make cookie dough. The use of different ingredients in the same base can lead to vastly different outcomes.

The same can be said of materials science and the study of low-dimensional materials. Haixuan Xu, assistant professor of materials science and engineering, and his JDRD team propose to expand the understanding of the effect of point defects and impurities on low-dimensional materials such as graphene.

“We are trying to see how we can control the creation of defects in low-dimensional materials,” said Xu. “A defect could be a hole or what you call a vacancy in the material system. Then we want to put something else in there. That’s called a dopant.”

Dopants, or impurities, are inserted into a substance to change its electrical or optical properties. This is often done with semiconductor materials currently of interest in the advancement of electronics and computing.

The ultimate aim of Xu’s work is to advance the science of quantum computing by contributing to the foundation of knowledge needed in order to move forward.

“The joint LDRD [Laboratory Directed Research and Development] and JDRD work is trying to see if we can precisely control the atomic and material environment used to prepare and maintain coherent superposition of quantum states, which is the heart of the challenge for quantum computing. But there are many steps in between,” said Xu.

Xu’s project will study these defects in an attempt to ascertain how the use of particular dopants can affect the base material, particularly with relation to the electronic structure of the system. In order to do this, his team must first determine how to create defects in a controlled manner, a task that is currently under way.

Xu’s ORNL partner, Stephen Jesse, will tackle the same problem from an experimental angle using the national lab’s scanning electron beam microscope and helium ion microscope. Xu’s team will be hammering away at the theoretical understanding through computer modeling, with the intention of bringing their results together to provide a more complete picture.

“There is nice synergy between the Oak Ridge and UT teams. We’re actually studying the same scientific problem from two different and complementary perspectives,” said Xu. “Hopefully we can get a better understanding of what’s really going on in the system.”

Algorithms May Enhance Computational Efficiency

Imagine a busy airport. Planes from a dozen airlines take off and land hundreds of thousands of times a day, heading to and from hundreds of cities. Passengers scurry from plane to plane catching connecting flights to arrive at their final destination. To ensure that the whole system works reliably and efficiently, complex and large-scale decisions have to be made.

In mathematical language, the decision-making process can be formulated as what computer scientists call an optimization problem—one that looks for the best possible solution out of many alternatives. In the airport setting, this approach will ensure that thousands of planes can take off and land in an orderly fashion and relatively on schedule.

Optimization models that fully capture the essence of industrial-scale problems require computational capacities afforded only by high-performance computing systems. Oleg Shylo, assistant professor of industrial and systems engineering, is hoping to utilize these systems in his JDRD work by designing new algorithms to work in parallel.

“The approach that we’re taking is so-called cooperative solvers, where a group of optimization algorithms work together and, as the word cooperative implies, they communicate with each other to solve problems,” said Shylo.

The use of cooperative solvers comes with its own unique set of constraints, as the communication between these algorithms can quickly overwhelm the system’s bandwidth. Optimization problems frequently have a large number of variables and need to be solved very quickly, something that can’t happen if algorithms are using all the computing power to share updates.

“As in human communication, if you have 10,000 people talking to each other at the same time it’s going to be chaotic and you won’t have time to do any useful work,” said Shylo. “The same applies to algorithms. You need to design communication structures and topologies to alleviate those kinds of issues.”

Shylo will use theoretical models to discover the best communication structures. Through his LDRD partnership with Jack Wells, director of science for the Oak Ridge Leadership Computing Facility at ORNL, Shylo will have the opportunity to test his algorithms on one of the high-performance computing systems, such as Titan, at the national lab. He hopes these tests will confirm his theoretical work and clear the path toward solving real-world optimization problems.

Designing Better Aluminum Alloys

On November 2, 1944, Howard Hughes’s infamous plane the Spruce Goose made its inaugural and final flight, traveling a single mile. Contrary to its name, the Spruce Goose was constructed primarily of laminated birch in an attempt to work within the government’s wartime materials restrictions. Weighing approximately 300,000 pounds, the plane was estimated to travel less than a quarter of a mile per gallon of fuel. In contrast, a modern Boeing 747 travels approximately five miles on a gallon.

Aside from the modern technology operating within the 747, the most obvious difference between the two aircraft lies in their construction materials. The 747 is made of a high-tech aluminum alloy. The study and improvement of aluminum alloys continue to make up an important area of research within the field of materials science.

Lighter, more heat-resistant alloys can improve the performance and fuel efficiency of transportation vehicles like cars and planes. This is precisely the subject Seungha Shin, assistant professor of mechanical, aerospace, and biomedical engineering, proposes to address with his JDRD project. Shin’s team, in conjunction with his partner Amit Shyam, a research scientist at ORNL, is investigating mass and thermal transport near microstructural interfaces in the search for better-designed aluminum alloys.

 

“Aluminum is kind of a soft metal, so in order to have better mechanical properties we add copper. In mechanical properties, most failures occur near the interface, so when designing a microstructure, the interface is very important,” said Shin.

Shin hopes his project will lead to a more thorough understanding of how to design alloys to create microstructures that provide specific effects, such as greater durability under high temperature conditions.

“Normally, light metals are not that good at high temperatures, so to use that kind of lightweight metal we need to develop some new materials,” said Shin.

Microstructures have an important role to play in the development of these new materials. The unique microstructure of a material determines its physical properties, such as toughness, corrosion resistance, and thermal transport behavior. These properties then determine the applications and industries for which that material is suited. Essentially, microstructures dictate the uses of materials.

“If we have an aluminum-copper alloy, it creates a certain phase of microstructure called the theta phase. It begins all mixed together, then forms the theta prime phase followed by the theta phase,” said Shin. “The theta phase is not good, but the theta prime phase can create a stronger aluminum alloy. We want to prevent the diffusion, or transition, from the theta prime to theta phase.”

Shin’s team will focus on computational simulations of interfacial transport at the atomic level with the goal of developing a theoretical framework for controlling these properties. His ORNL partners will model on both fundamental and system scales. Shin’s work will provide the missing piece for effective alloy design, with wide-ranging applications in air and ground transportation.

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