Undergraduate poster presentation schedule

	Undergraduate poster presentation schedule October 27, 10.00-11.30am
Joshua Hill	Construction and Characterization of Spin-polarized ³He targets Electron scattering experiments which study the internal structure of the neutron require spin- polarized neutron targets. We produced, characterized, and studied such targets using He-three as a stable neutron substitute. We mixed the alkali which transfer spin to the He in an inert environment for the first time at William and Mary. We then constructed targets of differing pressures, and alkali contents. We performed Nuclear Magnetic Resonance and Electron Paramagnetic Resonance tests to determine the targets' polarization under multiple testing parameters. These data help the lab's ongoing studies of the mechanisms behind the depolarization of the He within the targets. A Rb-only target displayed no losses, while significant losses were observed in a hybrid (Rb/K) target. We conclude that the K and or the higher temperatures required by hybrid targets are behind the phenomenon of large pumping chamber polarization losses.
William Bergan	Application of a Kalman Filter to the MINERvA Test-Beam Beamline We applied a Kalman ﬁlter to the test-beam beamline in order to obtain improved values for the momenta of particles and better uncertainties in those values, taking into account the effects of multiple scattering. In order to check the accuracy of our ﬁt, we compared the measured values of downstream hit locations with those predicted by the Kalman ﬁlter and divided by the expected error. Fitting these residual plots to a Gaussian distribution, we found a mean of -0.18 ± 0.005 times the expected error and a standard deviation of 1.09 ± 0.004 times the expected error. We used an iterative process to determine the errors in momentum, ﬁnding them to average to 11.2 MeV, with pions having a mean momentum error of 8.5 MeV and protons having a mean error of 16.7 MeV.
Sara Williams	TBA
Evan Crisman	Anisotropy In Vanadium Dioxide Thin Films Vanadium Dioxide is a material that has attracted a great deal of study because of the metal to insulator transition it exhibits with increasing temperature. How this transition occurs is still not well understood. We report anisotropy in electrical and optical properties through the metal- insulator transition in Vanadium Dioxide grown on a monocrystalline Rutile thin film. We compare it to the isotropic metal-insulator transition of Vanadium Dioxide grown on quartz, which is polycrystalline.
Daniel Brooker	TBA
Bain Bronner	Whispering Gallery Mode Resonators: Development, Characterization, and Applications Whispering Gallery Mode Resonators (WGMRs) are optical resonant cavities. They "hold in" light for long periods, effectively making the light travel very long distances. Utilizing this long distance allows for precise tracking in small changes to the disk. Since the light is traveling around the rim of the disk hundreds to thousands of times, any small change in the size also multiplied by that factor. Thus WGMRs allow us to replace traditional Fabry-Perot resonators of several meters with tiny disks which are only millimeters across. By producing high Q-factor disks, we aim to create miniature sensors which would be able to track environmental variables (such as temperature) with great precision.
David Specht	TBA
Elana Urbach	Measuring the Unraveling Force of single-strand DNA From Carbon Nanotubes Using Optical Traps A single walled carbon nanotube (SWNT) can form a complex with single stranded DNA (ssDNA) and has great potential for many biological applications. It is thought that ssDNA wraps in a helical pattern along the SWNT, but the exact binding mechanism and associated energies are not well understood. In this study we present the first use of optical tweezers to investigate the binding mechanism of the DNA-SWNT complex. We found that the ssDNA unwraps in discrete steps of 5 to 10 base pairs from the SWNT at forces of around 20 pN. We also compared three different DNA sequences: (GT)₁₅, (AT)₁₅, and (GT)₃₀, but found no significant differences in unwrapping forces or unraveling lengths between the different sequences. These results vary significantly from previous studies of DNA-graphene interactions, and provide unprecedented resolution of DNA-SWNT interaction modes.
Paulo Black	Hyperbolic Dispersion in Curved and Flat Silver Filled Membranes In 2000 Sir John Pendry created the first metamaterial based on theoretical predictions made by Viktor Veselago in 1967. Since then, the field of metamaterials has flourished and become one of the main subdivisions of materials science. In the work done by this group we aim to experimentally explore one of the properties of metamaterials: hyperbolic dispersion of permittivity values. We used a tried and true experimental technique of layering dielectric and metal materials with a subwavelength periodicity. Alumina membranes were filled with silver nanowires by electroplating the porous membranes with a distance of repetition of roughly 40nm. With this process we produced metamaterials in which we attempted to produce a curvature that would allow for a unique property of materials with hyperbolic dispersion, hyperlensing. This poster outlines the techniques used to fabricate these metamaterials and curve them with successful results. Finally, we discuss applications of hyperlenses as well as possible future work that could stem from this research.
Timothy Milbourne	Making Physics "Phun": Developing A Conceptual Physics Curriculum
Rachel Hyneman	CHP Nanowires in Lithium Ion Battery Anodes CHP nanocrystals were synthesized by combining lithium hydroxide, copper (I) chloride and lithium nitrate in a diluted sulfuric acid solution. Different time and temperature conditions were used to determine the best method of synthesizing the desired nanowire structure. After synthesis, the compounds were washed in ethanol and deionized water to purify. Scanning electron microscope (SEM) testing allowed confirmation that the desired nanowire structure was forming. X-Ray diffraction (XRD) testing showed a high concentration of CHP, as well as excess copper oxide, which may have resulted from the copper chloride reacting with water. The final CHP mix was combined with graphite, a binding agent, and N-Methylpyrrolidone (NMP). This solution was coated onto aluminum foil to form a basic cathode to be inserted into a basic battery with a lithium anode. Pre- and post- measurements of the mass of the cathode foils and measurements of the mass of uncoated foils of the same dimensions allowed for the determination of changes in the mass of the CHP solution during the charging and discharging process. XRD testing of the used cathode foils revealed that the CHP crystals appeared to degrade during process. Other applications of the CHP nanocrystals are currently being researched.