Poster presentations will take place in the New Science Center Building (NSCB) Atrium at the College of Charleston, Charleston, SC (GPS coordinates: latitude= 32dgr 47' 5.15" N and longitude= 79dgr 56' 23.82" W).
Posters will be displayed during the entire meeting starting at 8:00 am, on Saturday, October 23, 2010. Poster presentations take place between 9:30 am - 10:00 am and between 12:00 pm - 1:00 pm. Please remove the posters no later than 3:00 pm on Saturday, October 23, 2010.
Poster # 1 Adaptation of a polycapillary optic XRF system for XRD analysis of crystal structures
Timothy Collart, North Georgia College & State University, Sarah P. Formica, North Georgia College & State University, Mark C. Spraker, North Georgia College & State University
A molybdenum x-ray fluorescence (XRF) system, which employs a polycapillary optic, is being adapted to allow for crystal structure analysis using x-ray diffraction (XRD). XRD requires a monochromatic x-ray beam; both filtering of the molybdenum Kβ and bremsstrahlung radiation with a Zirconium filter and diffraction of the molybdenum Kα radiation from a LiF crystal are being attempted. Once a monochromatic beam of sufficient intensity is produced, the diffraction pattern of an inorganic polycrystalline sample placed in this beam will be recorded on x-ray sensitive film. The system will then be modified to image proteins that are known to form crystals. This will allow for detection of crystal formation in new proteins, and possibly give information about their structures. Preliminary data will be presented.
Poster # 2 XRF Spectroscopy to Determine the Relative Concentrations of Iron in Blood Samples
Johanna Arnold, North Georgia College & State University, Sarah P. Formica, North Georgia College & State University, Mark C. Spraker, North Georgia College & State University
Accurate, rapid, and non-destructive methods to determine the concentrations of various elements in blood samples can be extremely useful to the medical community. The X-ray Composition, Imaging, and Trace Element Research group (XCITER) at North Georgia is studying the use of x-ray fluorescence (XRF) spectroscopy to measure metal concentrations in biological samples using a Molybdenum sealed-tube x-ray source and a slightly-focusing polycapillary optic. Preliminary data will be presented and future development will be discussed.
Poster # 3 Physics Education Research Group at North Georgia investigates gender-biased questions on the Force Concept Inventory
Kerry McGill, North Georgia College & State University, Sarah P. Formica, North Georgia College & State University, Mark C. Spraker, North Georgia College & State University
The Physics Education Research Group at North Georgia (PER GANG) has been investigating the Force Concept Inventory (FCI) and searching for gender-based differences in individual question responses given by beginning undergraduate physics students. In this study, approximately 300 students enrolled in calculus-based physics and algebra-based physics took the FCI pre-test. The results have been studied using a BIT coding method, which will be discussed. Individual responses to each question of males and females are cataloged and responsive trends to the questions will be observed. If characteristic differences in specific questions appear between males and females, then these questions will be further investigated. Preliminary data on this experiment will be presented.
Poster # 4 Compilation of an XRF elemental calibration database
Cassandra Major, North Georgia College & State University, Sarah P. Formica, North Georgia College & State University, Mark C. Spraker, North Georgia College & State University
X-ray Fluorescence (XRF) spectroscopy is a rapid and noninvasive technique for detecting and identifying chemical elements in both organic and inorganic samples. This project utilizes North Georgia's Molybdenum sealed-tube x-ray source and slightly-focusing polycapillary optic to measure the XRF from a large number of elemental and compound calibration samples. This data will then be used to quantitatively determine the chemical composition of future studied samples. Elemental and compound calibration samples have been acquired and measurements are underway. The experimental technique and some preliminary data will be presented.
Poster # 5 Vortex instability in molybdenum-germanium superconducting films
Manlai Liang and Milind N. Kunchur, Univ. of South Carollina, Dept. of Physics and Astronomy, Columbia, SC 29208
Phone: 803 777 1907, Email: email@example.com and firstname.lastname@example.org
We studied the high driving force regime of the current-voltage transport response in the mixed state of amorphous molybdenum-germanium superconducting films to the point where the flux flow becomes unstable. The observed nonlinear response conforms with the classic Larkin-Ovchinikov picture with a quasiparticle-energy-relaxation rate dominated by the quasiparticle recombination process. The measured energy relaxation rate was found to have a magnitude and temperature dependence in agreement with theory. [This work was supported by the U. S. Department of Energy through grant number DE-FG02-99ER45763.]
Poster # 6 Understanding and Counteracting Effects of Triboelectricity in Planetary Exploration Systems
Andrew Carnes, Luke Sollitt, and Joel C. Berlinghieri, The Citadel, Department of Physics
Email: email@example.com, Phone: 843 953 6942
Ongoing work in modeling and mitigating effects of triboelectric charging of regolith particles in sample-handing systems deployed on the surface of Mars will be presented. The modeling work updates previous results of Anderson et al (2009) by including the effects of particle-on-particle triboelectric charging in the simulation. Triboelectric charging of regolith particles is a major obstacle to analysis of samples by landed platforms on planets such as Mars or the Moon. The tribolectric effects can hinder the ability to analyze regolith samples on different planets due to the cross-contamination of the leftover regolith on the walls of the sample containers. The effects of particle-on-particle interactions as described by Forward, Lacks and Sankaran (2009) may explain the problems that were observed. Additionally, laboratory efforts at NASA's Jet Propulsion Laboratory in Pasadena, CA to observe if different radiation types and activity levels could counteract the effects of triboelectric charging will be described.
Poster # 7 Chemical evolution of high redshift sub-damped Lyman-alpha systems
Som Debopam, Kulkarni V. P.,University of South Carolina, Meiring, J., Lauroesch, J., York, D., Peroux, C., Khare, P., University of Massachusetts, University of Louisville, University of Chicago, Obs. Astron. de Marseille-Provence, Utkal University.
Absorption lines in quasar spectra offer a unique window into the high redshift universe providing useful information about galaxy evolution. The damped Lyman-alpha absorbers (DLAs) and sub-DLAs contain the majority of neutral gas in galaxies at high redshift. They also allow a direct determination of interstellar element abundances in galaxies as a function of redshift. Our recent studies indicate, surprisingly, that the sub-DLAs appear to be more metal-rich than the DLAs, especially at low redshifts. The differences between DLAs and sub-DLAs pose open questions regarding the chemical evolution of galaxies. To investigate these questions furhter, we are expanding the abundance measurements for DLAs and sub-DLAs to higher redshifts. We have recently observed 15 absorbers at redshifts z > 1.7 using the MIKE spectrograph at the 6.5 meter Magellan Clay telescope in Chile. We will present observational data from this study on element abundances in a few high redshift DLAs and sub-DLAs.
Poster # 8 Determinants Of Choosing a Career in Science: Immigrants vs. Non-immigrants
Florin D . Lung, Department of Physics and Astronomy, Kinard Hall, Clemson University, Geoff Potvin, Zahra Hazari, Department of Engineering & Science Education, and Department of Mathematical Sciences Holtzendorff Hall Clemson University, Philip M. Sadler, Gerhard Sonnert, Science Education Department, Harvard-Smithsonian Center for Astrophysics Cambridge, MA, 02138
Email: firstname.lastname@example.org, Phone: 864-280-9030
Science-related activities, both in-class and extracurricular, during high school or even earlier, are known to influence the students' attitudes toward science and their career choice. The PRiSE survey of a nationally representative sample of two-year and four-year college students (Project PRiSE, NSF 0624444) provides extra insights in this subject. This investigation focuses on the evolution of interest in science for the first-generation and second-generation immigrant students' subsample of the PRiSE survey. Also, specific differences in experiencing science education for members of this group as opposed to students from US families are drawn.
Poster # 9 Biopolymers for Medical Applications: Polyglycerol Sebacate (PGS) Doped Hydroxyapatite (HA)
Phone: 843-953-7457, Email: email@example.com
Maria Teruel*, Narayanan Kuthirummal, and Nicole Polyachenko1,
Department of Physics and Astronomy, College of Charleston, SC 29424. 1Department of Plastic and Reconstruction Surgery, Wake Forest University, NC 27106.
In the investigation to engineer the ideal scaffolding device for cleft palate repair polyglycerol sebacate (PGS) doped with hydroxyapatite (HA) was chosen for its elastomeric and biodegradable properties. In addition to these properties, PGS can be simply and cost- effectively synthesized, generating a viscous prepolymer which can be further reacted to form a covalently cross-linked polymer. Hydroxyapatite, a bioceramic filler, was integrated into the polymers to form a composite with high porosity and improved mechanical properties that serves as a good substrate for cell attachment during the repair process. In an attempt to obtain consistent degree of polymerization, Differential Scanning Calorimetry (DSC) was utilized to identify an acceptable glass transition temperature (Tg), between -18 and -21 °C. At this Tg, it was determined that the polymer was sufficiently polymerized to point where it was durable yet pliable enough to use for cleft palate devices. In the synthesis of PGS 3% and 5% HA, a Tg of -20.10 °C and -21.72 °C, respectively, was achieved and analytical tests were then performed on the polymers. Methods of analysis included FT-IR Scanning, X- Ray Diffraction, and Tensile Strength Testing. Results of the analyses allowed for determination of degree of polymerization and physical capabilities of the polymer.
Disclaimer: All presentations at SACS-AAPT Fall 2010 reflect the views of the individual speakers and do not represent those of the AAPT or any of its supporters.