Bulletin of the American Physical Society
Joint Fall 2010 Meeting of the Texas Sections of the APS, AAPT, Zone 13 of SPS and the National Society of Hispanic Physicists
Volume 55, Number 11
Thursday–Saturday, October 21–23, 2010; San Antonio, Texas
Session FA6: SPS |
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Chair: Richard Cardenas, St. Mary's University Room: University Center III Hidalgo Room, 2nd floor |
Friday, October 22, 2010 3:00PM - 3:12PM |
FA6.00001: Synthesis of Porous Silicon by non-contact etching with a strong oxidizer D. Olivia Skeen, Toni Sauncy Porous silicon thin films have been produced by photochemical synthesis with a solution of hydrofluoric acid (HF) and the oxidizer cobalt nitrate. A 20mW HeNe laser was used to produce the local electric field necessary for the formation of the porous matrix on the surface of the crystalline silicon (n-type, antimony doped) substrate. Samples prepared with variations in process time from 15 minutes to 5 hours were examined using photoluminescence and Raman spectroscopy as well as scanning electron microscopy. Results indicate that the presence of the oxidizer during synthesis enhances the intensity of the photoluminescence produced by the porous silicon post-processing when compared with samples prepared using only HF. In addition, post process analysis reveals that the porous layer on the samples is present only on samples processed for less than 2 hours. [Preview Abstract] |
Friday, October 22, 2010 3:12PM - 3:24PM |
FA6.00002: ALE Meta-Analysis of Schizophrenics Performing the N-Back Task Zachary Harrell MRI/fMRI has already proven itself as a valuable tool in the diagnosis and treatment of many illnesses of the brain, including cognitive problems. By exploiting the differences in magnetic susceptibility between oxygenated and deoxygenated hemoglobin, fMRI can measure blood flow in various regions of interest within the brain. This can determine the level of brain activity in relation to motor or cognitive functions and provide a metric for tissue damage or illness symptoms. Structural imaging techniques have shown lesions or deficiencies in tissue volumes in schizophrenics corresponding to areas primarily in the frontal and temporal lobes. These areas are currently known to be involved in working memory and attention, which many schizophrenics have trouble with. The ALE (Activation Likelihood Estimation) Meta-Analysis is able to statistically determine the significance of brain area activations based on the post-hoc combination of multiple studies. This process is useful for giving a general model of brain function in relation to a particular task designed to engage the affected areas (such as working memory for the n-back task). The advantages of the ALE Meta-Analysis include elimination of single subject anomalies, elimination of false/extremely weak activations, and verification of function/location hypotheses. [Preview Abstract] |
Friday, October 22, 2010 3:24PM - 3:36PM |
FA6.00003: The Search for the W' and Right-Handed Neutrino Guy Grubbs In this experiment, a search was conducted for the W' and right-handed neutrino in the W' llqq channel. A program was created in order to read data, make cuts, and look for interesting data points. After this program was created, signals of different W' and right-handed neutrino masses were input along with data and cuts were made. In the end, the experiment was able to conclude with a 95{\%} confidence level that a W' particle does not exist for right-handed neutrino masses of 100 and 300GeV. More signals of different W' and right-handed neutrino masses should be tested in order to set limits on their existence in this channel. [Preview Abstract] |
Friday, October 22, 2010 3:36PM - 3:48PM |
FA6.00004: Developing functional Optical Tweezers for Undergraduate Research Tanya Dax, Toni Sauncy Optical tweezers are useful for manipulation of microscopic materials without damage from physical contact. This project utilized a 20mW HeNe laser (wavelength 632.8nm) and a reconfigured standard teaching-laboratory microscope to form a stable diffraction limited trap. A simple method of live recording of moving particles was developed with the use of AVT SmartView and NI Vision Assistant. The physical setup was altered several times to eliminate sources of misalignment, until an optimal configuration was achieved and optical trapping and manipulation of a polystyrene microsphere was successfully recorded. Additionally, Calcite particles on the order of 1 micrometer were manipulated with the optical trap. [Preview Abstract] |
Friday, October 22, 2010 3:48PM - 4:00PM |
FA6.00005: Estimating the sheet resistance of a thin film with an Ohm-meter Alan Woodall, Wilhelmus Geerts In order to get an estimate of the sheet resistance of a thin film sample, without having access to a four point probe measurement system, one could measure the resistance with a simple digital multimeter using two electrodes. For thin film materials that form a good electric contact with the chrome plated electrodes, the two point probe resistance measured by placing the two electrodes in the middle of the sample is proportional to the sheet resistance. The proportionality factor between the measured resistance and the thin film's sheet resistance appears to be dependent on the ratio of the electrode spacing (s) and the electrode diameter (d). For s/d is equal to 12, the proportionality factor is one, which means that the measured resistance is a good estimate of the film's sheet resistance. The error is less than 10 percent for s/d values between 9 and 16. [Preview Abstract] |
Friday, October 22, 2010 4:00PM - 4:12PM |
FA6.00006: Design and construction of a Hall Effect Measurement system Ethan Gully, Travis Little, Sebastian Requena, Toni Sauncy We have constructed a Hall Effect sample holder that facilitates quick sample change and insures that the sample is uniformly located for each measurement. The 4 point off-the-shelf sample card was integrated into an existing floor magnet with custom designed and constructed mounts. The sample holder is well suited for these measurements, allowing for adjustments in all three of the coordinate axes directions so that even small samples can be accurately positioned for measurement between the poles of the magnet. The sample holder is interfaced and controlled with LABView software. The measurements are made using a suite of Keithley instruments. The design and construction will be discussed and preliminary calibration of the Hall Effect system will be presented. [Preview Abstract] |
Friday, October 22, 2010 4:12PM - 4:24PM |
FA6.00007: MicroBooNE: Proton Decay Background Studies Jessica Esquivel, Richard Cardenas MicroBooNE is a Liquid Argon Time Projection Chamber detector(LArTPC) that detects and analyzes neutrino interactions using the FermiLab booster neutrino beam as well as the Neutrinos from the Main Injector beam(NuMi).[4] This experiment was proposed to look into the excess of low energy neutrino events observed by the Mini-BooNE experiment. Unlike MiniBooNE, MicroBooNE has the capability to distinguish between electrons and photons. MicroBooNE is also able to see proton decay modes that Water Cherenkov detectors like Super K aren't able to see. MicroBooNE is a benchmark for all future massive Liquid Argon(LAr) detectors and because of this, MicroBooNE will also be used to study Proton Decay background rejection, Particle Detection, and Readout procedures. [Preview Abstract] |
Friday, October 22, 2010 4:24PM - 4:36PM |
FA6.00008: Science Policy: Behind the Scenes Travis Barnett I served nine weeks as an intern in the House of Representatives Committee on Science and Technology. For the majority of the summer I served in the Research and Science Education Subcommittee, researching, among other things, cyber-enabled learning, cybersecurity, and alternate energy costs. My internship was created and funded by the John and Jane Mather Foundation for the Arts and Sciences, and as the only merit-based science committee intern, I felt a great responsibility to prove my worth in the Committee. Immersed in government and science policy, I feel very learned and prepared to participate in these fields. [Preview Abstract] |
Friday, October 22, 2010 4:36PM - 4:48PM |
FA6.00009: Interaction of Mastoparan with Model Membranes Justin Haloot The use of antimicrobial agents began during the 20th century to reduce the effects of infectious diseases. Since the 1990s, antimicrobial resistance has become an ever-increasing global problem. Our laboratory recently found that small antimicrobial peptides (AMPs) have potent antimicrobial activity against a wide range of Gram-negative and Gram-positive organisms including antibiotic resistant organisms. These AMPs are potential therapeutic agents against the growing problem of antimicrobial resistance. AMPs are small peptides produced by plants, insects and animals. Several hypotheses concede that these peptides cause some type of structural perturbations and increased membrane permeability in bacteria however, how AMPs kill bacteria remains unclear. The goal of this study was to design an assay that would allow us to evaluate and monitor the pore forming ability of an AMP, Mastoparan, on model membrane structures called liposomes. Development of this model will facilitate the study of how mastoparan and related AMPs interact with the bacterial membrane. [Preview Abstract] |
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