Series
Undergraduate Research Spring Symposium and Awards

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Event Series
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Associated Organization(s)

Publication Search Results

Now showing 1 - 10 of 28
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    Fluid Mechanical Instabilities of an Acoustically Excited, Turbulent Jet Flame
    (Georgia Institute of Technology, 2010-03-16) Ma, Hsin-Hsiao
    This paper describes investigations and analysis of the evolution of the flame brush thickness of acoustically excited, lean, turbulent premixed flames. Two sets of experiments were conducted with a piloted, conical Bunsen flame and a swirl stabilized, annular flame. Phased locked particle image velocimetry (PIV) and OH planar laser induced fluorescence (PLIF) were used to measure flow velocities, track the evolution of the flame, and visualize the flow and flame dynamics over a frequency and amplitude sweep. The results show that the flame brush thickness grew in a monotonic style for the unforced case, while the flame brush thickness grew in a step-like function under acoustic excitation. The velocity field revealed the locations of the peak vorticity was not at the same locations as the peak velocities. The results imply that acoustic excitation to a turbulent flame plays a significant role in the flame's global heat release response and that flame stretch may play a significant role in the evolution of the flame brush thickness.
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    Development of Demo Robot for Piezoelectrically Actuated Gripper
    (Georgia Institute of Technology, 2010-03-16) McPherson, Timothy
    Applications of a small piezoelectric actuator developed by Dr. Jun Ueda will be explored. This will involve the development of a demo robot that incorporates the piezoelectric cellular actuator technology to actuate a tweezer-style end effector. The robot will be designed to give the end effector the freedom to move in a horizontal plane and to change orientation about a single axis. Classical control techniques will be used to accurately control the end effector's position. Development of the demo robot will also include the creation of a internet based interface for giving commands to the robot remotely.
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    ERP Correlates of Visuospatial Attention
    (Georgia Institute of Technology, 2010-03-16) Chung, Andy
    At almost every given moment, the visual system in our brain is constantly bombarded by visual stimuli. Unfortunately, our brain does not have an infinite amount of neurons to process every visual stimulus in the environment so it must select some at the expense of others. That is, objects compete for representation in the limited capacity visual system. Studies have shown that stimuli presented in close proximity exhibit greater competition than stimuli that are farther apart. Attention is also biased towards more salient objects through top-down mechanisms meaning that a task relevant object will be selected over another object. Previous work has also identified possible neural correlates for both spatial and saliency mediated competition. The N2pc component of the event-related potential (ERP) may be related to spatially-mediated competition, while the subsequent Ptc component may be related to the operation of a top-down biasing mechanism. In this study, a colored target and decoy are displayed at various spatial separations to participants while their ERPs are recorded. The participant will not be told the color of the target in advance so that both target and decoy must be attended. The participant is expected to bias processing towards the target and away from the decoy based on top-down factors. A positive correlation between the amplitude of the N2pc and Ptc components of the ERP and the amount of spatial and top-down mediated competition will provide converging evidence that those two components map to their respective biasing mechanism.
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    High Fidelity Photopatterning and Characterization of Hydrogels for Three-Dimensional Cell Co-Culture
    (Georgia Institute of Technology, 2010-03-16) Bloodworth, Nathaniel
    Hydrogels provide a unique environment for the in-vitro study of cell behavior in 3D, and the technique of photolithography allows for controlled cell patterning by enabling the creation of well-defined hydrogel structures. However, current photolithographic techniques are limited in their ability to produce hydrogels on the micro scale with thicknesses sufficient for use in a true 3D cell culture system. We demonstrate methods for patterning hydrogels derived from both biological and synthetic polymers with enhanced fidelity and thickness. Oligo(poly(ethylene glycol) fumarate) (OPF) and chondroitin sulfate methacrylate (CSMA) polymers were synthesized using previously described methods1,2. OPF and CSMA hydrogels 550 - 3000 μm in size were photocrosslinked in microfluidic devices purged with nitrogen gas under 365 nm UV light for 12 minutes at an intensity of 10.5 mW/cm2. Hydrogels photopatterned under nitrogen were found to have significantly higher thickness than those patterned in the presence of room air, exceeding 1 mm for gels with widths greater than 600 - 800 μm. Hydrogel size correlated with the size of the photomask, enabling facile system calibration. The photopatterning methods were also employed to laminate two differentially swollen hydrogels to form a single construct with a well-defined and stable interface visualized using fluorescence microscopy. These results demonstrate that we are capable of producing hydrogels with improved spatial resolution at the μm to mm scale that may be laminated to form well defined patterns of cells in a 3D co-culture system. References: 1Jo S et al. Macromolecules. 2001;34:2839-44. 2Bryant S et al. Macromolecules. 2004; 37:6726-6733.
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    Optimal Cannulation Location
    (Georgia Institute of Technology, 2010-03-16) Jung, Philsub
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    X-ray Determination of the Stacking Order in C-face Graphene
    (Georgia Institute of Technology, 2010-03-16) Tinkey, Holly
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    The Image of Women in Advertising
    (Georgia Institute of Technology, 2010-03-16) Martin, Kelsey
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    Nanocomposite Strain Sensors
    (Georgia Institute of Technology, 2010-03-16) Tzanavaris, Christopher
    This study explores the use of polydimethylsiloxane (PDMS) reinforced with vapor-grown carbon fibers (VGCF) as a strain sensor. The operational principal of the nanocomposite sensors with VGCF content above the percolation threshold is that as the material is strained, its conductivity decreases because the conductive network of carbon fibers disconnects whereas upon release of the strain the conductivity increases. However, due to energy dissipation in the PDMS there is a big lag in the conductivity during the loading-unloading cycle that leads to sensors with no reproducible strain-conductivity behavior. This challenge is overcome by tuning the monomer to curing agent ratio used to formulate the PDMS matrix.
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    Visual Network Traffic Classification Using Multi-Dimensional Piecewise Polynomial Models
    (Georgia Institute of Technology, 2010-03-16) Sanders, Sean ; Jampana, Sahitya
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    Assistive Technology: The Application and Rhetoric of Cochlear Implants [2009]
    (Georgia Institute of Technology, 2009-04-01) Chatel, Lindsay