This is the schedule of talks for the Rice CUWiP 2017 Conference.
Session I, Brockman 103
Session II, Brockman 200
Session III, Brockman 300
Dynamical Nuclear Magnetic Resonance Imaging of Micron-scale Liquids
Aimee Sixta, University of Texas System
We report our efforts in the development of Nuclear Magnetic Resonance Force Microscopy (NM- RFM) for dynamical imaging of liquid media at the micron scale. Our probe contains microfluidic samples sealed in thin-walled (m) quartz tubes, with a micro-oscillator sensor nearby in vacuum to maintain its high mechanical resonance quality factor. Using 10 m spherical permalloy magnets at the oscillator tips, a 3D T1-resolved image of spin density can be obtained by reconstruction from our magnetostatics-modelled resonance slices; as part of this effort, we are exploring single-shot T1 measurements for faster dynamical imaging. We aim to further enhance imaging by using a 2ω technique to eliminate artifact signals during the cyclic inversion of nuclear spins. With the ultimate intent of imaging biological cells after modeling has been refined.
Revealing Electronic States in Topological Condensed-Matter Systems
Grace Pan, Yale University
Electrons in transistor-like devices interact and dance with each other in unexpected ways. The potential landscape of a material allows us to probe and visualize exotic quantum states of matter that behave just as beautifully as, say, stars in distant galaxies. This research focuses on the danc- ing of electrons in a unique class of materials called “topological insulators”, which have remarkable energy- and computing-based potential. Topological insulators are characterized by the presence of conducting surface or edge electrons despite having an insulating bulk. These surface electrons are protected from backscattering and hence give us a new paradigm of perfect electronic transport. However, the experimental challenge begins with revealing and manipulating the unique electronic states in topological insulators. In this work, I take a topological insulator material system and experimentally probe it at near absolute-zero temperatures. Informed by past experiments and theory, and enabled by modern nanotechnological methods, I hope to reveal interesting electronic behavior guided by topological transport.
Effect of Temperature and pH on the Nanostructural and Nanomechanical Prop- erties of Chitosan Films
Ramona Luna, University of Texas Rio Grande Valley
Developing a matrix that can mimic tissue-like environment for cell cultures and molecular studies can help reduce the loss of some cell functions that occur when studies are performed in vitro. Of particular interest is chitosan: abundant and renewable biopolymer that is also biodegradable and non-toxic. This research focuses on synthesizing CS films under various conditions and for multiple applications. We are using several techniques to characterize properties of the CS films. The con- tact angle technique is used to determine the hydrophobicity, hydrophilicity, and the surface free energy. The atomic force microscopy (AFM) is used to determine the roughness, nanostructure, and nanomechanical properties. By investigating the properties of these surfaces, the needed bio- material platform for a specific biological system can be designed and manipulated to increase its performance and lifetime. AFM images showed that the roughness of the surface is affected with the pH variations. Our surface free energy preliminary results have not shown relation to pH changes. Our future work will focus on studying the adhesion properties of the CS films by adsorbing cells and proteins on the films and studying the cell-surface and protein-surface interaction using AFM force measurements and fluorescence microscopy.
Electron Dynamics in H/H− Collisions with Copper Surfaces
Jamie Stafford, Lamar University
This research investigates the charge transfer processes during H/H− collisions with Cu(100) and Cu(111) surfaces, using the Wave-Packet Propagation technique. This technique is extremely pow- erful for ion-surface interactions, because it provides the exact solution of the dynamical problem without approximations. The projectile energy, incidence/exit angles with the surface, distance of closest approach, and surface band structure are important factors that influence the projectile survival probability. Cu(100) and Cu(111) surfaces are particularly interesting because they have a complex band structure with energy gaps. Band gaps along the surface normal are expected to strongly influence the projectile-surface charge transfer. This research provides valuable informa- tion regarding: (a) H/H− energy level shifts during the interaction; (b) H/H− survival probabilities. Besides its significance for fundamental research, this study has direct technological applications. Charge transfer studies are crucial for understanding and promoting progress in applied fields such as: ion-surface collisions, plasma wall interactions, thin film growth, catalysis, and aeronautical and space engineering.
Raman Spectroscopy of 3-D Printed Polymers
Vanessa Espinoza, Texas Lutheran University
Additive manufacturing (AM) techniques, such as 3-D printing are becoming an innovative and effi- cient way to produce highly customized parts for applications ranging from automotive to biomed- ical. Polymer-based AM parts can be produced from a myriad of materials and processing con- ditions to enable application-specific products. However, bringing 3-D printing from prototype to production relies on understanding the effect of processing conditions on the final product. Ra- man spectroscopy is a powerful and non-destructive characterization technique that can assist in determining the chemical homogeneity and physical alignment of polymer chains in 3-D printed materials. Two polymers commonly used in 3-D printing, acrylonitrile butadiene styrene (ABS) and polycarbonate (PC), were investigated using 1- and 2-D hyperspectral Raman imaging. In the case of ABS, a complex thermoplastic, the homogeneity of the material through the weld zone was investigated by comparing Raman peaks from each of the three components. In order to investigate the effect of processing conditions on polymer chain alignment, polarized Raman spectroscopy was used. In particular, the print speed or shear rate and effect of strain on PC filaments was investi- gated with perpendicular and parallel polarizations.
Construction of an Excitation Laser for Laser Cooling Rb-87
Lindsay Hutcherson, University of South Alabama
New research in the area of atomic and molecular physics often includes the use of a magneto- optical trap (MOT) and multiple lasers. In order to understand repulsive van der Waals forces through ultracold atom research, we must utilize the technique known as laser cooling. Laser cool- ing implements multiple lasers to create inelastic collisions between Rydberg atoms and photons to gradually cool and slow the atom. The excitation laser, used to excite atoms to this Rydberg state, is an important component to this system. This laser will need to implement a 480 nm diode, a current control device, and a temperature control in order to maximize and safely control its power. As the construction of this laser comes to a close, the limitations and performance of the equipment must be tested thoroughly. This presentation will focus on the construction and implementation of an excitation laser for a laser cooling system.
Construction of an Ex Vacuo Ion Trap
MacKenzie Warrens, University of Dallas
Trapped ions are important because they can be used to study fundamental quantum phenomena and could potentially be used as qubits for quantum computing. One of the devices that can be used to trap ions is a Paul trap. As part of my REU project at UCLA during the summer of 2016, a vacuum chamber with a support structure was designed and constructed for a linear Paul trap that has the electrodes outside the vacuum chamber. A barium ion source was also made by melting barium chloride powder on a strip of platinum. While barium ions have not been trapped yet with this new apparatus, a working barium ion source was made, and a vacuum chamber that reaches pressures on the order of 10−9 torr was constructed. The design and building of this linear Paul trap, as well as suggested first experiments, will be presented.
3 Tesla Superferric Cable-in-Conduit Dipole for the Ion Ring of the JLEIC Collider
Kathryn O’Quinn, Texas A&M University
The design and construction of a 3 Tesla model dipole for the Ion Ring lattice of the electron-ion collider JLEIC is presented. The dipole uses a 15 kA NbTi cable-in-conduit (CIC) conductor in a superferric magnetic design. All turns of the winding are precisely positioned in the body of the dipole using G-11 support components, and the flared ends are formed using motorized bend tooling. Liquid helium flows through the center tube of the CIC conductor so that all NbTi strands are in direct contact with liquid for stabilization against micro quenches. A mockup winding was built and evaluated to confirm the precision of conductor placement and the fabrication methods. We are now beginning construction of long-length CIC cable and we will then build a 1.2 m model dipole.
Stable Orbits for Exomoons in Earths Cousin (Kepler-452b) Orbiting a Sun-like Star
Niyousha Davachi, University of Texas at Arlington
Kepler 452b, also nicknamed Earth’s cousin, was discovered orbiting the habitable zone (HZ) of a G2 Star (Jenkins et al. 2015). This exoplanet is considered a super Earth, with a mass of 5±2 ME and a radius of 1.11 RE; and is arguably the first rocky, habitable exoplanet to orbit a sun-like star. With a period of 385 days, conditions are prompt to be similar to those of Earth, and while Kepler-452b orbits the HZ of its parent star, its habitability could also be affected by the presence of an exomoon. Motivated by the need to understand conditions of habitability and orbital stability of Kepler-45b, we have performed a series of N-body integrations to examine the possibility of the exoplanet hosting an exomoon(s). Our results give a range of physical parameters leading to stable orbits for exomoons around this habitable super Earth.
Finding the Shape of Glowing Openings by Filtering Light with Polarizers
Suzanne Wheeler, Lamar University
The purpose of our research is finding the shape of an opening illuminated from behind with uni- form light using a polarimetric method. Basically, we polarize the light emitted by an opening using a system of polarizers so we can describe the shape of this opening. The topic was inspired by an article published in Nature (2006) by Leonard at al., which talks about the asymmetry of a core collapse supernova based on the analysis of the degree of polarization of the cores radiation induced by the gaseous cloud around it. We built in-house a table-top setup including a blackbody cavity having small openings of various shapes covered with a diffuser. This system simulates the core of supernovas. Our control signal is a circular opening and our probe signal is formed by various open- ings such as triangle, polygons, crescent, etc. A complex optical system, which includes polarizers, lenses, and filters, are used to gather light into a high-sensitivity light sensor, while a motor allows us to steadily rotate another polarizer (or better named analyzer) connected to the motion sensor. Malus law is used for data processing: The raw data follows a cosine squared variation but with a variable amplitude depending on the shape of the opening. The analysis of these amplitudes and their departure from our control signal allows finding the shape of the openings. We acknowledge the Society of Physics Students (SPS) National Branch for the 2016 UG Research Award and the STAIRSTEP program at Lamar for financial support.
The Theory of Groups in Quantum Mechanics
Arlenne Gonzalez de la Rosa, University of Texas at Austin
In this talk, we introduce the concept of groups and Lie algebras to understand a few concepts of quantum mechanics. We first give the example of isospin followed by conservation laws and unification theories.