Engineering a Better World
Imagine it. Design it. Build it. Improve it.
“Only research for the sake of understanding can lead to a scientific breakthrough.”Rafael Tadmor
Associate professor of chemical engineering
Think of the things you use every day—a computer to send an e-mail, a cell phone to call a friend, a car to drive on roadways and over bridges. The list of items that make our lives easier is almost infinite. And without engineers, we wouldn’t have any of it.
The faculty and students in the College of Engineering know this. That’s why their motto is: Imagine it. Design it. Build it. Improve it.
These are exciting times for research in the college. “Projects are bringing recognition to Lamar from a national and international audience,” said Jack Hopper, dean.
Dewdrops cling to a flower petal. Raindrops hang from a leaf. Dishwater drops rest upon a plate. When you tilt these surfaces, the drops may stay stick or flow down. Until recently, we didn’t quite know why. But we do now, thanks to Rafael Tadmor, associate professor of chemical engineering.
Tadmor researches drop adhesion on surfaces. In 2004, he was the first to write equations to relate the value of the equilibrium contact angles of drops on surfaces to measured values. His method is still the only way to make this calculation. In a research paper on that discovery, Tadmor credits W. Ted Mahavier, professor of mathematics, with help in validating some of the equations. In 2008, Tadmor wrote another paper that combined his conclusions from 2004 and finally explained theoretically why sometimes drops flow down and sometimes they don’t.
But proving a theory on paper and seeing the physical reality of it with your own eyes are two different things. To measure the forces associated with retaining a drop on a surface, Tadmor and his team of students built the first Centrifugal Adhesion Balance (CAB) machine. (He currently has funding from the National Science Foundation to make adjustments and improvements to the machine.) With the help of the CAB device, the engineers discovered in 2009 that drops hanging from a surface require more force to slide than drops resting on a surface. In December 2009, "Measurement of Lateral Adhesion Forces at the Interface between a Liquid Drop and a Substrate" was published in Physical Review Letters, a prestigious scientific journal. “We made a huge discovery that echoed throughout the world,” Tadmor said of his team that included students Prashant Bahadur, Aisha Leh, Hartmann E. N’guessan, Rajiv Jaini and Lan Dang.
The drop-adhesion discovery can lead to possible applications in bioengineering for tissue regeneration and pharmaceutical research on inhalation drugs. Tadmor, who was the Distinguished Faculty Lecturer for 2010, will let other researchers deal with the practical applications. He’s more interested in proving scientific foundations. “Only research for the sake of understanding can lead to a scientific breakthrough,” he said.
Cleaning Up Wastewater
Cleaning up wastewater is a dirty job, but somebody has to do it. Luckily, C. Jerry Lin, professor of civil engineering, is really good at it. Lin and his team provided the initial engineering design of a portable wastewater treatment system called the Deployable Aerobic Aqueous Bioreactor (DAAB) System – a modular, rugged, flexible and deployable treatment system for municipal wastewater. “It was designed around a patented consortium of microorganisms that can be activated rapidly to degrade organic pollutants,” Lin said. “The system is capable of achieving the U.S. Environmental Protection Agency’s wastewater discharge standard within 48 hours after deployment, as compared to two to three weeks of start-up time in conventional biological treatment systems, with low energy consumption and little waste sludge production.” It can be housed in a standard 20-foot or 40-foot shipping container, depending on the desired flow rate throughput. The system can address the needs of military and emergency relief applications. The $2 million project is funded by the U.S. Army Corps of Engineers.
The technology won the 2010 Texas Environmental Technology Award for Wastewater Treatment Breakthrough and is the runner up for a Wall Street Journal Environmental Technology award in the environment category.
Lin, the 2008 University Scholar Award recipient, also established two research laboratories at Lamar. The Water Characterization and Research Laboratory develops water and wastewater treatment technologies that address the challenges of fresh water availability and waste stream disposal. The lab particularly specializes in physicochemical and biological treatments, membrane filtration, desalination and enhanced coagulation. In addition to quantifying water quality parameters pertinent to meeting drinking water standards and wastewater discharge requirements, the lab is equipped with a wide array of research instruments including high performance liquid chromatography (HPLC), ion chromatography (IC), a flow injection analyzer, a UV-VIS spectrophotometer, a total organic analyzer, an inverted microscope, fluorescence microscopy, a cryostat micro-slicing machine, as well as bioreactors for microbial growth kinetic studies.
The Air Quality Modeling Laboratory specializes in advanced atmospheric modeling for investigating the effectiveness of emission reduction for air quality improvement, intercontinental transport of air pollutants, fate and cycling of atmospheric mercury and air pollution processes for ozone and aerosols. “We perform first-principle air simulations using comprehensive meteorological and photochemical models at urban, regional and hemispheric sites to investigate the fate of air emissions from both anthropogenic and natural sources,” Lin said.
The lab has two high-performance computational (HPC) Linux clusters (32-bit and 64-bit) with 120 CPUs and a random-access memory (RAM) capacity of 90 gigabytes (GB), more than 20 terabytes (TB) of network data storage and 12 workstations for data analysis and visualization.
Both labs are actively carrying out research funded by the U.S. Department of Agriculture, the U.S. Environmental Protection Agency, the U.S. Department of Defense, the Texas Commission on Environmental Quality, the Texas Air Research Center and the Texas Hazardous Waste Research Center. The average funding level in the past five years is about $500,000 per year, according to Lin.
Metallic electronic devices such as cell phones won’t work if the conductive metals corrode. John Zhanhu Guo (right), assistant professor of chemical engineering, and Suying Wei (below), assistant professor of chemistry, are tackling that problem.
The pair received $300,000 in National Science Foundation funding for a project titled “Synergistic Conductive Multifunctional Polymer Nanocomposites with Soft and Hard Nanofillers.” It is co-sponsored by the Nanoscale Interdisciplinary Research Teams (NIRT) program and Materials Processing and Manufacturing program. “This project will target conductive polymer nanocomposites from two general approaches,” Guo said. “One is combining different conductive nanofillers such as metal nanoparticles into insulating polymer such as epoxy resin. The other is to utilize the conductive polymer matrix such as polypyrrole and the fillers will introduce different functionalities.”
Guo and Wei will lead their teams in implementing the proposed tasks related to the conductive polymer nanocomposites. The major polymer nanocomposite (PNC) synthesis and processing will be carried out in Guo’s Integrated Composites Laboratory (ICL), and characterization and property analysis will be carried out in Wei’s laboratory.
The grant provides funding for developing a series of chemically stable conductive polymer nanocomposites (cPNCs) to tackle a central problem—corrosion of conductive metals—facing metallic electronic devices including microwave absorbers to prevent microwave irradiation, explosive chemical sensors, magnetic field sensors and electrochromism-based smart windows. If successful, the results of this research will make a significant contribution to the rapidly developing field of polymer-based conductive nanostructural materials. “The to-be-developed cPNCs will have multifunctionalities integrating lightweight, electrical conductivity and magnetic properties in one polymer system, which can replace the easily oxidized metals for electronic device applications,” Guo said.
The cPNCs, either from combining different conductive nanofillers into insulating polymer or from utilizing the conductive polymer matrix, bring prospects of organic-based devices with reduced weight density, increased integration and multi-functionality. The collaboration with Western Digital Corporation and Ocean Nanotech LLC will facilitate the possible commercialization of the newly developed cPNCs, Guo said.
Broadening Participation in Engineering
Conducting engineering research and bridging the gap in education for underrepresented students is what a BRIGE grant is all about.
Xuejun Fan, associate professor of mechanical engineering, was awarded $174,999 for a National Science Foundation Broadening Participation Research Initiation Grant in Engineering (BRIGE) titled “Research and Education on Mechanical Behavior of Wafer-Level Films in Integrated Systems.”
Microelectronics devices are getting smaller and smaller, Fan explained. The silicon chips used in iPhones are just one example. “Thin-film technology is one of the critical processes to make the devices smaller,” he said. “Wafer-level film is a new process that is compatible with the wafer process. This grant intends to investigate the mechanical behavior of this new type of film.”
Fan and his team will investigate the fundamental mechanics issues associated with thin film rupture at reflow process in microsystems. The three-dimensional integration of micro- and nano-electronics systems requires innovations of manufacturing processes at the wafer level, Fan explained. The development of wafer-level thin film lamination is critical for the success in further function integration and lower power consumption. A multi-physics approach, which includes new theory development and numerical implementation, will be established to investigate the mechanical behavior of wafer-level films in integrated systems. Multi-scale analysis will be developed to understand the failure processes at the nano-, micro-, and macro-scales, respectively. Experiments will generate data for in-situ moisture weight gain, moisturesensitivity and reflow. Specially designed small-scale assemblies will be fabricated and tested. The test data will be used to validate the theoretical predictions and numerical simulation results.
If successful, the results of this research will directly benefit the technology development of three-dimensional micro and nano-electronics packaging and system integration by providing an optimal manufacturing processing window. The research outcome will assist in the design of new wafer-level film materials by providing an optimal design protocol. Knowledge gained from this investigation will avoid trial-and-error experiments and will contribute to making new process development and system-level integration a reality, Fan said.
As a BRIGE grant, an education plan will be integrated to broaden the participation of engineering researchers including members from underrepresented groups and people with disabilities in the engineering disciplines. The education plan also includes outreach programs to minority undergraduate students that will promote science, technology, engineering and mathematics (STEM) careers.