News Archive 2017

Team Strains Two-Dimensional Ferroelectrics With Light

Reference: University of Arkansas Newswire May 04, 2017

FAYETTEVILLE, Ark. — University of Arkansas researchers discovered an unusual deformation of a new potential class of two-dimensional materials that is created upon exposure to light. The effect, called photostriction, is a delicate mechanical coupling of the material to electromagnetic radiation that has never been reported within the context of two-dimensional materials before.

Their paper, "Photostrictive Two-dimensional Materials in the Monochalcogenide Family," will be published in a forthcoming issue of the Physical Review Letters. University of Arkansas researchers Raad Haleoot, Charles Paillard, Thaneshwor Kaloni, Mehrshad Mehboudi, Bin Xu, Laurent Bellaiche and Salvador Barraza-Lopez of the Department of Physics collaborated on the project.

"Group-IV monochalcogenide monolayers are interesting potential two-dimensional ferroelectrics that have an intrinsic in-plane electric moment and an extreme structural tunability," Barraza-Lopez said. "Upon discussion with Laurent and Charles, who had work on this effect in bulk (three dimensional) ferroelectrics, we decided to explore the mechanical response of monochalcogenide monolayers under illumination, and found that this two-dimensional structure can be strained uniaxially as the material sits under ambient light."

This is how the effect works: Electrons are excited from the valence band onto the conduction band when these materials are illuminated. As this electronic excitation process takes place, the electron cloud about atoms is modified with respect to its shape prior to illumination. Such a change of the electron cloud upon illumination "screens" the intrinsic in-plane electric moment, so the material contracts (strains) along the direction defined by the electric dipole in response.

"I wish to highlight the crucial leadership by Mr. Haleoot in carrying out extremely delicate calculations, and the close guidance by Dr. Paillard that made these results possible."

The computational work was carried out at Comet, a Supercomputer at San Diego Supercomputer Center (XSEDE TG-PHY090002). Barraza-Lopez is also funded by the Department of Energy.

NASA Selects Arkansas' First CubeSat

Reference: University of Arkansas Newswire May 3, 2017

FAYETTEVILLE, Ark. – Arkansas’ first CubeSat, a small satellite selected by NASA for space education and research, will observe the Earth’s climate and measure the composition and concentration of atmospheric gases.

In February, NASA announced the selection of ArkSat-1 as one of 34 satellites from 19 states and the District of Columbia that will be launched into space between 2018 and 2020. ArkSat-1 is being developed by Adam Huang, associate professor of mechanical engineering, and Josh Pennington, doctoral student in the Microelectronics and Photonics program, in the Engineered Micro/Nano-Systems Laboratory. They will deliver the satellite to NASA for launch in 2020.

From space, ArkSat-1 — a 10-centimeter, or nearly 4-inch, cube that is almost twice the size of a Rubik’s Cube — will point a calibrated light toward Earth. Terrestrial telescopes instrumented with spectrophotometers will track this light and measure the composition and concentration of various atmospheric gases.

“This could help build a stronger understanding of the complex dynamics that occur in the atmosphere and give us insight into how different geographical locales affect the atmosphere around those areas,” Pennington said. “For instance, how much more methane is in the air around large agricultural areas? How much more concentrated is carbon dioxide in cities than the countryside?”

ARKSat-1 will also demonstrate a deorbit technology being developed at the U of A’s Engineered Micro/Nano-Systems Laboratory by Morgan Roddy, also a doctoral student in the Microelectronics-Photonics program. Roddy’s deorbiter, which recently won second place in a student design competition at the University Nanosatellite Engineering Consortium’s Global Meeting in Varna, Bulgaria, is designed to reduce space debris from small satellites. The deorbiter inflates a thin-membrane balloon that increases drag on a satellite, slowing its reentry into the Earth’s atmosphere and causing the satellite to disintegrate.

“Which means that, if everything works correctly, the CubeSat will quickly burn up in Earth's atmosphere,” Pennington said.

The U of A team – composed of Huang, Pennington and Roddy as well as John Lee, doctoral student in mechanical engineering, and undergraduate students – plan to complete ARKSat-1 by the end of 2019. It will then be turned over to NASA for integration onto a rocket. Pennington said it will likely take from 3 to 6 months for a launch opportunity. The researchers expect the mission to last three months.

The U of A researchers are collaborating with other universities and organizations in Arkansas on the project. Huang is the primary investigator. Co-investigators include Larry Roe, associate professor of mechanical engineering and the director of the Arkansas Center for Space and Planetary Sciences at the U of A; Vincent Chevrier, assistant research professor at the Arkansas Center for Space and Planetary Sciences; Ed Wilson and Charles Wu at Harding University; Yupo Chan at the University of Arkansas at Little Rock; and Constance Meadors at Pulaski Technical College. Development of ARKSat-1 is funded by the Arkansas Space Grant Consortium.

Initially developed by academia in the early-2000s for promoting space technology education, CubeSats gained popularity after the Department of Defense, NASA and the National Science Foundation began providing CubeSat-based research funding in the late-2000s. Today, they are the standard satellite technology, providing space access to both traditional and non-traditional participants in technology and missions.

Electrical Engineering Professor Lends Expertise to the Air Force

Reference: University of Arkansas Newswire April 26, 2017

Morgan Ware, assistant professor of electrical engineering, has been appointed as a fellow in the 2017 Air Force Research Lab Summer Faculty Fellowship Program at the Air Force Research Laboratory in Dayton, Ohio. He will be joining the Sensors Directorate, which develops sensor technology for air- and space-borne applications.

The U.S. Air Force Research Lab Summer Faculty Fellowship Program provides science, mathematics and engineering faculty with the opportunity to participate in research aimed at solving Air Force challenges. Faculty fellows spend eight to 12 weeks at participating Air Force research facilities. The program is sponsored by the Air Force Office of Scientific Research.

"This is a great opportunity for Morgan," said Juan Carlos Balda, head of the Department of Electrical Engineering. "He will be able to gain familiarity with research work performed by the Air Force, identify potential topics for future research proposals and network with program managers in the Department of Defense. In addition, the Air Force research personnel will have a chance to learn about the excellent facilities that U of A has for new material research."

Ware's research currently focuses on semiconductor crystal growth for optical and electrical devices. During the fellowship, he will be studying the incorporation of tin and germanium, both elements chemically similar to silicon, into silicon crystal growth. 

Silicon is at the heart of the semiconductor electronics industry, which is reaching physical limitations in terms of size, electrical conductivity, and as a result, computer processing speed. This ultimately limits future improvements.  The integration of tin and germanium into this technology will facilitate a potential conversion from electronic devices to optical or photonic devices, which will increase speed and reduce heat production. This will also provide a platform for seamless integration with photonic communication technologies, which are well established.

The results of the research performed during Ware's tenure at the Air Force Research Laboratory will be an increased understanding of the mechanisms and the environmental conditions that allow for the controlled growth of crystals containing alloys of these elements and the resulting optical and electrical properties exhibited by these crystals. This research will provide the groundwork for the future development of more efficient and faster electronic systems and improved sensor and light source technologies, which will enhance both communications and information processing for the Air Force.

Engineering Professors Named Fellows of Professional Organization

Reference: University of Arkansas Newswire April 25, 2017

Jin-Woo Kim, professor of biological and agricultural engineering, and Yanbin Li, Distinguished Professor of biological and agricultural engineering, have been named fellows by the American Institute for Medical and Biological Engineering, or AIMBE.

According to its website, AIMBE's College of Fellows "consists of over 1,500 individuals who are the outstanding leaders, engineers, entrepreneurs, and innovators in medical and biological engineering," and fellows represent the top two percent of the medical and biological engineering community.

"We are proud of the recognition of two of our most prolific research faculty working on the cutting-edge of the interface of biology and engineering," said Lalit Verma, head of the Department of Biological and Agricultural Engineering. "This honor is well deserved as their interdisciplinary works are addressing some of the grand challenges facing our society."

Kim directs the Bio/Nano Technology Laboratory in the Department of Biological and Agricultural Engineering and the Institute for Nanoscience and Engineering. His primary research focus is in the area of bio/nano technology, or biologically inspired nanotechnology, which spans interdisciplinary fields of biological engineering, biomedical engineering, biology, chemistry, and nanotechnology. Specifically, his research aims to develop nanoscale bio/abio interfacing technology for programmable integrations of biomimetic advanced materials and devices for biological and biomedical applications.  He has authored over 100 peer-reviewed publications and five book chapters, and he has two granted and one pending patents. Kim was recently elected as vice president of publications of the Nanotechnology Council of the Institute Electrical and Electronics Engineers and he is an IEEE Nanotechnology Distinguished Lecturer.

Li holds the Tyson Endowed Chair in Biosensing Engineering. His research focuses on biosensors and bioinstrumentation, microbial predictive modeling, quantitative risk assessment and food safety engineering. His research has applications in the screening of avian influenza in poultry, rapid detection of foodborne pathogens, predictive models of pathogenic bacteria in food products and risk assessment of microbial hazards in food systems. He has authored over 150 peer-reviewed publications and has received 12 patents.

Non-Flammable Graphene Membrane Developed for Safe Mass Production

Reference: University of Arkansas Newswire April 12, 2017

FAYETTEVILLE, Ark. – University of Arkansas researchers have discovered a simple and scalable method for turning graphene oxide into a non-flammable and paper-like graphene membrane that can be used in large-scale production.

"Due to their mechanical strength and excellent charge and heat conductivities, graphene-based materials have generated enormous excitement," said Ryan Tian, associate professor of inorganic chemistry in the J. William Fulbright College of Arts and Sciences. "But high flammability jeopardizes the material's promise for large-scale manufacturing and wide applications."

Graphene's extremely high flammability has been an obstacle to further development and commercialization. However, this new discovery  makes it possible to mass-produce graphene and graphene membranes to improve a host of products, from fuel cells to solar cells to supercapacitors and sensors. Tian has a provisional patent for this new discovery.

Using metal ions with three or more positive charges, researchers in Tian's laboratory bonded graphene-oxide flakes into a transparent membrane. This new form of carbon-polymer sheet is flexible, nontoxic and mechanically strong, in addition to being non-flammable.

Further testing of the material suggested that crosslinking, or bonding, using transition metals and rare-earth metals, caused the graphene oxide to possess new semiconducting, magnetic and optical properties.

For the past decade, scientists have focused on graphene, a two-dimensional material that is a single atom in thickness, because it is one of the strongest, lightest and most conductive materials known. For these reasons, graphene and similar two-dimensional materials hold great potential to substitute for traditional semiconductors. Graphene oxide is a common intermediate for graphene and graphene-derived materials made from graphite, which is a crystalline form of carbon.

The research was conducted by Hulusi Turgut, doctoral student in the U of A microelectronics-photonics program and the Institute for Nanoscience and Engineering. Part of the material's characterization was done by Fengjiao Yu and Wuzong Zhou at the University of St. Andrews in the United Kingdom.

The researchers' findings were published in The Journal of Physical Chemistry. This intellectual property is patented by the University of Arkansas.

Students Awarded Summer Internships With the Office of Naval Research

Reference: University of Arkansas Newswire March 23, 2017

Four students affiliated with University of Arkansas students – two graduate and two undergraduate – will spend the summer interning with the U.S. Navy at the Naval Research Laboratory in Washington, D.C., and the Space and Naval Warfare Systems Center Pacific in San Diego.

Graduate students David French and Stephen Bauman, as well as undergraduate sophomore Madison Whitby, are full-time students at the University of Arkansas. Undergraduate senior Zachary Brawley, a student at the University of Central Arkansas in Conway, performed a Research Experience for Undergraduates at the U of A in the Department of Physics last summer. All four students are active members of a research group led by Joseph Herzog, an assistant professor in the Department of Physics.

French is a doctoral candidate in the Department of Physics. Bauman, who earned his master of science in microelectronics-photonics, is pursuing a doctorate in the same field. Whitby is a double major in mechanical engineering and physics. Brawley will graduate this spring from the Department of Physics and Astronomy at Central Arkansas and plans to begin graduate school in the fall.

French will intern at the Space and Naval Warfare Systems Center Pacific, where he will work on ultrashort, pulsed, laser-beam control. Bauman, Whitby and Brawley will all be working at the Naval Research Laboratory in their respective 10-week programs. Bauman will work on a project involving coupling plasmonics and 2-D materials. Whitby and Brawley will work in the same laboratory, studying fiber-optic acoustic sensors.

"I am proud of these students," said Herzog. "They have done excellent research in my lab, and I am confident they will contribute to the research needs of the U.S. Navy and the Office of Naval Research."

The internships are facilitated by the Naval Research Enterprise Intern Program through the Office of Naval Research and American Society for Engineering Education. As stated on the program website, "This ten-week intern program is designed to provide opportunities for undergraduate and graduate students to participate in research, under the guidance of an appropriate mentor, at a participating Navy laboratory."

Sides Named Director of Office of Industry Engagement at the UofA

Reference: University of Arkansas Newswire February 9, 2017

FAYETTEVILLE, Ark. – Cynthia Sides has been named director of the Office of Industry Engagement at the University of Arkansas. Sides, a native Arkansan who received her doctorate in chemistry and biochemistry from the University of Arkansas in 2007, will serve as a central administration contact between the university and industries throughout the state and country.

She has been with the Office of the Vice Provost for Research and Economic Development since 2013, where she has been involved with Arkansas industry interaction and worked as the associate director for the Office of Entrepreneurship and Innovation. Her new role continues her work developing ties between industry and academia, creating entrepreneurial opportunities for STEM students and helping researchers commercialize their work.

“This office is a resource,” Sides said. “I want it to be the place where companies can reach out and say, ‘We need assistance.’ And I can say, ‘What can I help you with?’ As a land grant and flagship institution, that is part of our mission.”

Jim Rankin, vice provost for research and economic development, said establishing the Office of Industry Engagement reflects the university’s commitment to that mission, and will benefit students.  

“Our researchers can help industry solve problems and drive economic growth in the state and beyond, and industry can help our students gain real-world experience before they enter the job market,” Rankin said. “Cynthia will focus on making those connections across campus and across the state. I look forward to working with her in the new role.”

Sides also teaches the Emerging Technologies in Industry course, which directly matches students in physics, chemistry/biochemistry, biology, engineering and other majors with industries seeking novel solutions for problems. She has written about entrepreneurship and economic development in Arkansas for Arkansas Money & Politics magazine, and developed a mentoring program connecting U of A STEM majors with young female students in south Arkansas interested in science and engineering.

Doctoral Student Wins Second Place in International Design Competition

Reference: University of Arkansas Newswire January 18, 2017

Morgan Roddy, a microelectronics-photonics doctoral student, recently won second place in a student design competition at the University Nanosatellite Engineering Consortium's Global Meeting in Varna, Bulgaria. The competition challenged students to design a deorbit system for CubeSats, a class of small satellites. Deorbit systems are important because international agreements dictate that any spacecraft must deorbit within 25 years to mitigate the accumulation of space junk.

Roddy's design, the Solid-State Inflation Balloon deorbiter, has three major components: a solid-state gas generator, an inflatable balloon and a package to store electronics and components throughout spacecraft operation. The gas generator is on a small chip that contains heaters positioned under 'micro-wells' of sodium azide. When the heaters activate, the sodium azide decomposes and produces nitrogen gas. The balloon then inflates with gas and the deorbit process begins by providing the spacecraft with more surface area for drag.

"Ultimately, my system can be thought of as a parachute for a CubeSat," Roddy said. "The only difference is the parachute happens to be a balloon."

The design would significantly reduce the deorbit lifetime of CubeSats. Currently, a CubeSat placed in a 550 kilometer orbit naturally deorbits in about 25 years. Roddy's design would see the same spacecraft deorbit in about a year for larger CubeSats and in about four months for smaller ones.

Additionally, Roddy's design could increase the altitude a CubeSat can reach. CubeSats are currently limited to a maximum altitude of 550 kilometers. However, the deorbit system Roddy has engineered could facilitate flying altitudes as high as 1,000 kilometers without violating the 25 year rule.

The deorbit design project is funded by the NASA Space Technology Mission Directorate's Small-Spacecraft Technology Program. Roddy, a Doctoral Academy Fellow, is the project's chief engineer and his adviser Adam Huang is the program manager.