Expert-to-Expert: GTRI Experts Share Their Perspectives on Science, Engineering and Research
Professional Education
Each year, GTRI scientists and engineers teach more than half of the courses offered through Georgia Tech’s Distance Learning and Professional Education Program.
The Georgia Tech Research Institute employs some of the world’s most experienced scientists and engineers. Our experts enjoy sharing their perspectives on science, engineering and their GTRI research.
Bookmark this page and check back from time to time to learn what’s on the minds of our renowned researchers.
Xu, J., Suarez, D., Gottfried, D. Detection of avian influenza virus using an interferometric biosensor
Show Abstract
An interferometric biosensor immunoassay for direct and label-less detection of avian influenza through whole virus capture on a planar optical waveguide is described. The assay response is based on index of refraction changes that occur upon binding of virus particles to unique antigen-specific (hemagglutinin) anti- bodies on the waveguide surface. Three virus subtypes (two H7 and one H8) in buffer solution were tested using both monoclonal and polyclonal capture antibodies. The real- time response of the antigen–antibody interaction was measured and was shown to be concentration-dependent, with detection limits as low as 0.0005 hemagglutination units per milliliter. A simple sandwich assay was shown to further increase the biosensor response.
Chen, C., Levitin, G., Hess, D.W., Fuller, T.F. XPS investigation of Nafion membrane degradation
Show Abstract
After treatment in different Fenton’s reagents, chemical changes in Nafion® membranes were analyzed by X-ray photoelectron spectroscopy (XPS) and clear evidence of polymer degradation was observed. Exposure of the membrane to 2h of X-ray radiation did not affect the chemical structure of the membrane. However, treatment with various Fenton’s reagents indicatedthat the (CF2)n polymer backbone had decomposed.
Ready, W.J. Carbon Nanotube Arrays for Photovoltaic Applications
Show Abstract
Electrochemical double-layer capacitors, or supercapacitors, have tremendous potential as high-power energy sources for use in low-weight hybrid systems for space exploration. Electrodes based on single-wall carbon nanotubes (SWCNTs) offer exceptional power and energy performance due to the high surface area, high conductivity, and the ability to functionalize the SWCNTs to optimize capacitor properties. This paper will report on the preparation of electrochemical capacitors incorporating SWCNT electrodes and their performance compared with existing commercial technology. Preliminary results indicate that substantial increases in power and energy density are possible. The effects of nanotube growth and processing methods on electrochemical capacitor performance is also presented. The compatibility of different SWCNTs and electrolytes was studied by varying the type of electrolyte ions that accumulate on the high-surface-area electrodes.
Bi, W., Gray, G., Fuller, T. PEM Fuel Cell Pt/C Dissolution and Deposition in Nation Electrolyte
Show Abstract
Dissolution at the cathode and subsequent transport of platinum to the other cell components causes catalyst degradation in proton exchange membrane (PEM) fuel cells. Deposition of platinum in Nafion membrane was observed after potential cycling under hydrogen/air conditions. The deposited Pt formed a band in the ionomer, and a straightforward model was proposed to describe its location. The predicted position of the Pt band agreed with the experimental data. A simple scanning electron microscopy-energy dispersive spectroscopy analysis was used to estimate that ~13% of the platinum initially in the cathode was transported into the membrane following 3000 potential cycles.
Fain, W. Assessment of workplace product accessibility: A human factors perspective
Show Abstract
This paper illustrates the advantages of using human factors evaluation techniques as a method of informing rehabilitation service provider decisions about client care and assistive technology selection. Successful integration of accessibility evaluation techniques can strengthen an evidence based service program and offer service providers another tool for providing efficient, effective, and rapid services to individuals in need. With accessibility evaluation data showing the functional abilities required to operate a given product or set of products, it is possible to empirically demonstrate that an individual has the potential to successfully utilize the provided workplace equipment. Conversely, if the accessibility evaluation data reveal that the functional capabilities required to use a product exceed the capabilities of a given user, it would be possible to demonstrate the need for particular interventions or accommodations. With accessibility evaluation data, service providers can make better informed decisions about client care.
James, J.C., Bennett, G.W., and Rhodes, W.T. Imaging systems based on the encoding of optical coherence functions, J. Opt. Soc. Am. A 22, 1780-1788 (2005)
Show Abstract
An imaging scheme is described that is based on the transmission of image-forming information encoded within optical coherence functions. The scheme makes use of dynamic random-valued encoding–decoding masks placed in the input–output planes of any linear optical system. The mask transmittance functions are complex conjugates of each other, as opposed to a similar coherence encoding scheme proposed earlier by two of this paper’s authors that used identical masks. [Rhodes and Welch, in Euro-American Workshop on Optoelectronic Information Processing, SPIE Critical Review Series (SPIE, 1999), Vol. CR74, p. 1]. General analyses of the two coherence encoding schemes are performed by using the more general mutual coherence function as opposed to the mutual intensity function used in the earlier scheme. The capabilities and limitations of both encoding schemes are discussed by using simple examples that combine the encoding–decoding masks with free-space propagation, passage through a four-f system, and a single-lens imaging system.
Robinson, W., Haran, T., Caspall, J., Lafond-Favieres, V. MWIR Laser Reflectivity Measurement Program, Proceedings for Military Sensing Symposia, Active EO Sensors, August 2003
Show Abstract
This paper describes the elements of a MWIR laser reflectivity measurement program developed to support scenario modeling for the DARPA/AFRL MEDUSA program. The goal of the program is to (1) develop airborne instrumentation to make MWIR laser reflectivity measurements, (2) to develop a user friendly database specifically for digital modeling efforts, and (3) to populate the database with active MWIR reflectivity data and associated information necessary to support modeling and system design activities.
Lafond-Favieres, V., Hall, K., Medlin, B., Wagner, R., Welch, G. Designing Innovative Electronic Performance Support Systems, 2003 Society of Applied Learning Technologies Conference, Orlando FL, February 18, 2003.
Show Abstract
Today’s maintenance technicians require timely, situation-specific electronic task guidance and support while their managers desire increased performance and decreased costs. Innovative Electronic Performance Support System (EPSS) architectures provide user-centered and performance-centered electronic environments that allow users to accomplish tasks with fewer errors and better results, even when provided less training [4]. Electronic technical manuals, troubleshooting trees, context based training, and asynchronous communication tools provide alternatives to traditional maintenance protocols. This paper defines and explains the key features of an EPSS as applied to maintenance tasks using the US Navy P-3 Maintainers EPSS (MEPSS™) as an example product, developed by the Logistics and Maintenance Applied Research Center (LandMARC) at the Georgia Tech Research Institute. We conclude with an analysis of how this architecture can be applied to the medical field to address similar concerns.
Robinson, W., Welch, G., O'Neill, G. The Need for a Systems Engineering Approach For Measuring and Predicting the Degradation of Aging Systems And How It Can Be Achieved, Proceedings of the Applied Vehicle Technology Panel Symposium on Life Management Techniques for Aging Air Vehicles, NATO
Show Abstract
This paper will explore the need for a comprehensive approach to measuring, and predicting, degradations in aging NATO aircraft and use of these predictions in a ‘systems approach’ to solving the challenges faced in supporting these aircraft. Various groups within the NATO countries have already accomplished significant progress in this area, so this paper is an attempt to refine a more global process that will provide the most useful results in the least amount of time. We believe that the appropriate application of both emerging and seemingly unrelated technologies, coupled with a systems engineering management approach, may provide acceptable results
Welch, G., Sheridan, J., Lafond-Favieres, V., Hall, K., Wagner, R. Electronic Performance Support Systems for Maintenance Tasks, Proceedings for SOLE (International Society of Logistics), Florida Logistics Conference, March 2001
Show Abstract
As systems increase in complexity while our workforce experience level decreases, performance support tools will become imperative to aid the user in task completion. The next generation support tools will integrate interactive troubleshooting aids, diagnostics, Maintenance Management Information Systems (MMIS), technical data, and training to significantly improve the maintainer’s ability to effectively and efficiently complete a repair task. Such systems can be the basis for continuous improvement of maintenance processes, having a positive impact on total ownership and support costs. Configuration management and failure history can also be used to reinforce the integration of the total supply chain, including links to provide data on parts availability. Recent advances in digital technology make technical data, interactive training, and improved diagnostics readily available for maintainers at the repair site. This improves the identification of specific failure increases and results in successful resolution. This paper outlines the architecture of an electronic performance support system (EPSS) and its application in a single instance using aircraft maintenance as a case example.
Ready, W.J. Oxidation of Carbon Nanotubes
Show Abstract
It has been previously shown that the addition of certain refractory oxides can affect the oxidation of graphite at high temperatures. Some refractory oxides, such as Al2O3, greatly increase oxidation, while others, such as TiO2, ZrO2, and MgO, greatly inhibit oxidation. This project will study the effects of these refractory oxides, as well as SiO2 (which was shown to have some effect of the oxidation of graphite) on single-wall carbon nanotubes.
Arepalli, S., Fireman, H., Huffman, C., Moloney, P., Nikolaev, P., Yowell, L., Higgins, C.D., Kim, K., Kohl, P.A., Turano, S.P., and Ready, W.J. Carbon-Nanotube-Based Electrochemical Double-Layer Capacitor Technologies for Spaceflight Applications
Show Abstract
Electrochemical double-layer capacitors,or supercapacitors, have tremendous potential as high-power energy sources for use in low-weight hybrid systems for space exploration. Electrodes based on single-wall carbon nanotubes (SWCNTs) offer exceptional power and energy performance due to the high surface area, high conductivity, and the ability to functionalize the SWCNTs to optimize capacitor properties.1 This paper will report on the preparation of electrochemical capacitors incorporating SWCNT electrodes and their performance compared with existing commercial technology. Preliminary results indicate that substantial increases in power and energy density are possible. The effects of nanotube growth and processing methods on electrochemical capacitor performance is also presented. The compatibility of different SWCNTs and electrolytes was studied by varying the type of electrolyte ions that accumulate on the high-surface-area electrodes.
