Ion-Beam Analysis Of Artificial Turf, 2017 Union College - Schenectady, NY
Ion-Beam Analysis Of Artificial Turf, Morgan Clark
Honors Theses
There have been considerable concerns in recent years that artificial turf used in many playing fields around the world may be unsafe. While the presence of heavy metals and carcinogenic chemicals have been reported in a number of studies more data and research are needed to determine if there is a real link between artificial turf and adverse health effects. We performed PIXE and PIGE analysis of artificial turf blade and infill samples to search for heavy metals and other possibly toxic substances. The samples were bombarded with proton beams from the 1.1-MV Pelletron tandem accelerator in the Union College …
A New Method For Measuring The Neutron Lifetime Using An In Situ Neutron Detector, 2017 Los Alamos National Laboratory
A New Method For Measuring The Neutron Lifetime Using An In Situ Neutron Detector, Christopher L. Morris, Edith R. Adamek, Leah J. Broussard, Nathan B. Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott A. Currie, Xiaoping Ding, Walter Fox, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Y. Liu, Mark Makela, Robert W. Pattie, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zhijing Tang, J. Vanderwerp, R. Bruce Vogelaar, Peter L. Walstrom, Zhehui Wang, Wanchun Wei, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck
Robert W. Pattie Jr.
Observing Orbital Angular Momentum Transfer From Electron Vortex Beams To Matter, 2017 Linfield College
Observing Orbital Angular Momentum Transfer From Electron Vortex Beams To Matter, Hannah Devyldere
Senior Theses
It is possible to produce electron beams with non-zero orbital angular momentum. Such beams, known as electron vortex beams, are theoretically able to transfer their orbital angular momenta to matter, causing the matter to rotate. Nanoparticles in an aqueous solution were observed with an electron vortex beam to detect the transfer of orbital angular momentum in a low-friction environment. Observing the transfer of orbital angular momentum to particles in solution is difficult due to the necessity of imaging the particles through a liquid and the random movement of particles in the solution. Thus, orbital angular momentum transfer to matter could …
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, 2017 University of South Carolina
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, Frances H. Cashman, Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, Pavel Bogdanovich
Physics and Astronomy Faculty Publications
Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753 Å (the H I Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium …
Building And Validating A Model For Investigating The Dynamics Of Isolated Water Molecules, 2017 Linfield College
Building And Validating A Model For Investigating The Dynamics Of Isolated Water Molecules, Grant Cates
Senior Theses
Understanding how water molecules behave in isolation is vital to understand many fundamental processes in nature. To that end, scientists have begun studying crystals in which single water molecules become trapped in regularly occurring cavities in the crystal structure. As part of that investigation, numerical models used to investigate the dynamics of isolated water molecules are sought to help bolster our fundamental understanding of how these systems behave. To that end, the efficacy of three computational methods—the Euler Method, the Euler-Aspel Method and the Beeman Method—is compared using a newly defined parameter, called the predictive stability coefficient ρ. This …
Continuity Of Heavy Rydberg Behaviour In The Ungerade Ion-Pair States Of H2, 2017 Bryn Mawr College
Continuity Of Heavy Rydberg Behaviour In The Ungerade Ion-Pair States Of H2, Alexander M. Chartrand, Robert J. Donovan, Kenneth P. Lawley, Elizabeth Mccormack
Physics Faculty Research and Scholarship
Heavy Rydberg behaviour and absolute quantum defects are reported for resonances in the ungerade manifold of H2 above the (1s, 3l) dissociation limit. The continuity of the vibrational progression of the B''B-bar state through the crossing with the 3p asymptote is demonstrated and a predominantly diabatic picture of the vibrational motion emerges, indicating that the ion-pair resonances possess little 61Σu+ state character.
Time-Resolved Thz Conductivity Of An Intermediate Band Semiconductor, 2017 Macalester College
Time-Resolved Thz Conductivity Of An Intermediate Band Semiconductor, Elliot Weiss
Macalester Journal of Physics and Astronomy
Intermediate band materials have promising applications as affordable, highly efficient solar materials. However, intermediate band solar cells exhibit low efficiency to date. Carrier recombination is a critical process that limits efficiency. If electrons relax to the valence band before they can be collected, their energy is lost. To help understand the recombination dynamics and physical properties of intermediate band semiconductors, we obtain time-resolved THz conductivity measurements of the intermediate band semiconductor, GaPAsN, at various temperatures. From our results, we build a model that provides insight to the recombination dynamics of GaPAsN.
Intervalley Scattering Rates In Tellurium Observed Via Time-Resolved Terahertz Spectroscopy, 2017 Macalester College
Intervalley Scattering Rates In Tellurium Observed Via Time-Resolved Terahertz Spectroscopy, Joshua R. Rollag
Macalester Journal of Physics and Astronomy
We conducted time-resolved terahertz spectroscopy measurements on the elemental semiconductor tellurium. Pump-probe measurements were used to find the conductivity as a function of time in single crystalline tellurium samples. It was found that the excitation dynamics in tellurium changes for photon energies of 1.03 eV and 1.55 eV. The change in these excitation dynamics was attributed to intervalley scattering effects. A model using intervalley scattering and Auger recombination was fit to the data, giving a value of 2.28 ps for the intervalley scattering time constant in tellurium.
Conductivity Measurements Of A Thermoelectric Nanomaterial Through Thz Spectroscopy, 2017 Macalester College
Conductivity Measurements Of A Thermoelectric Nanomaterial Through Thz Spectroscopy, Michaela S. Koller, James Heyman, Gunnar Footh
Macalester Journal of Physics and Astronomy
In today’s society there is a great demand on energy output—in the United States alone we rely heavily on non-renewable energy sources. Thermoelectric materials may be able to be used to create more efficient energy systems or recover wasted heat from inefficient technologies. This paper focuses on the conductivity of a new thermoelectric material that incorporates copper into a tellurium nanowire PEDOT:PSS material. The addition of copper seems to increase the conductivity of the material, although the exact relationship between the percentage of copper to tellurium and its affect on the conductivity is uncertain from the results.
Quasi-Optical Measurement For Low Loss Material Characterization In Submillimeter Wave Range, 2017 Portland State University
Quasi-Optical Measurement For Low Loss Material Characterization In Submillimeter Wave Range, Ha Khiem Tran, Thanh Ngoc Dan Le, Branimir Pejcinovic
Student Research Symposium
An accurate knowledge of dielectric constant of materials is required in many sub-millimeter wave applications. Free-space measurement of materials has always been one of the first choices due to their non-destructive nature and relatively simple sample preparation. However, free-space measurement systems at sub-millimeter frequency range suffer from two main problems: high loss because of divergent beam pattern and diffraction when the beam waist of the radiated beam is relatively large compared to the size of the sample under tests. In order to mitigate these issues, we set up a quasi-optical system using off-axis parabolic mirrors, which enhance the dynamic range …
Discontinuities In The Electromagnetic Fields Of Vortex Beams In The Complex Source-Sink Model, 2017 University of Nebraska - Lincoln
Discontinuities In The Electromagnetic Fields Of Vortex Beams In The Complex Source-Sink Model, Andrew Vikartofsky, Liang-Wen Pi, Anthony F. Starace
Anthony F. Starace Publications
An analytical discontinuity is reported in what was thought to be the discontinuity-free exact nonparaxial vortex beam phasor obtained within the complex source-sink model. This discontinuity appears for all odd values of the orbital angular momentum mode. Such discontinuities in the phasor lead to nonphysical discontinuities in the real electromagnetic field components. We identify the source of the discontinuities, and provide graphical evidence of the discontinuous real electric fields for the first and third orbital angular momentum modes. A simple means of avoiding these discontinuities is presented.
Developing Tools For A Precision Measurement Of Newton's Gravitational Constant Using Atom Interferometry, 2017 Georgia Southern University
Developing Tools For A Precision Measurement Of Newton's Gravitational Constant Using Atom Interferometry, Elizabeth Ashwood
Honors College Theses
We propose a new atom interferometry scheme for making a precision measurement of Newton's Gravitational constant (Big G) using NASA's Cold-Atom Laboratory which is scheduled to be deployed to the International Space Station in 2017. The proposed interferometer consists of splitting a harmonically confined Bose-Einstein condensate into multiple pieces. In a perfect harmonic potential, all of the pieces come to rest at the same time, at which point the harmonic trap is turned off. These initially motionless condensate clouds then accumulate different phases due to the relative velocity they develop caused by the gravitational attraction of a nearby source mass. …
Kinetic Theory Of Dark Solitons With Tunable Friction, 2017 University of Maryland
Kinetic Theory Of Dark Solitons With Tunable Friction, Hilary M. Hurst, Dimitry K. Efimkin, I. B. Spielman, Victor Galitski
Faculty Research, Scholarly, and Creative Activity
We study controllable friction in a system consisting of a dark soliton in a one-dimensional Bose-Einstein condensate coupled to a non-interacting Fermi gas. The fermions act as impurity atoms, not part of the original condensate, that scatter off of the soliton. We study semi-classical dynamics of the dark soliton, a particle-like object with negative mass, and calculate its friction coefficient. Surprisingly, it depends periodically on the ratio of interspecies (impurity-condensate) to intraspecies (condensate-condensate) interaction strengths. By tuning this ratio, one can access a regime where the friction coefficient vanishes. We develop a general theory of stochastic dynamics for negative mass …
Studies In Mesoscopics And Quantum Microscopies, 2017 Illinois Wesleyan University
Studies In Mesoscopics And Quantum Microscopies, Zhenghao Ding, Gabriel C. Spalding
Honors Projects
This thesis begins with a foundational section on quantum optics. The single-photon detectors used in the first chapter were obtained through the Advanced Laboratory Physics Association (ALPhA), which brokered reduced cost for educational use, and the aim of the single-photon work presented in Chapter 1 is to develop modules for use in Illinois Wesleyan's instructional labs beyond the first year of university. Along with the American Association of Physics Teachers, ALPhA encourages capstone-level work, such as Chapter 1 of this honors thesis, which is explicitly designed to play the role of passing on, to a next generation of physics majors, …
Improving Predictive Capabilities Of Classical Cascade Theory For Nonproliferation Analysis, 2017 University of Tennessee, Knoxville
Improving Predictive Capabilities Of Classical Cascade Theory For Nonproliferation Analysis, David Allen Vermillion
Doctoral Dissertations
Uranium enrichment finds a direct and indispensable function in both peaceful and nonpeaceful nuclear applications. Today, over 99% of enriched uranium is produced by gas centrifuge technology. With the international dissemination of the Zippe archetypal design in 1960 followed by the widespread illicit centrifuge trafficking efforts of the A.Q. Khan network, traditional barriers to enrichment technologies are no longer as effective as they once were. Consequently, gas centrifuge technology is now regarded as a high-priority nuclear proliferation threat, and the international nonproliferation community seeks new avenues to effectively and efficiently respond to this emergent threat.
Effective response first requires an …
Experiment And Simulation Of Single-Molecule Recycling, 2017 University of Tennessee, Knoxville
Experiment And Simulation Of Single-Molecule Recycling, Bo Wang
Doctoral Dissertations
This dissertation presents theoretical, numerical, and experimental research into a technique for extending the observation time of a single molecule in solution, while also enabling measurement of its diffusion coefficient. A confocal microscope is used to observe the fluorescently labelled molecule in aqueous solution, which is confined within a nanochannel. By focusing a laser beam into the nanochannel and applying electrokinetic flow along the tube, a molecule passes through the laser beam and emits a burst of photons. The molecule then passes back and forth through the focus while the voltage is repeatedly reversed at a fixed delay after each …
Silver Nanoparticles As A Potential Solar Absorber, 2017 Bowling Green State University
Silver Nanoparticles As A Potential Solar Absorber, Benjamin Hardy
Honors Projects
This work reports the development of Silver nanoparticles implanted into a polymer as a solar absorber. The plasmonic nature of silver nanoparticle allows for adjustments to be made in its UV-VIS-NIR absorbance spectrum. A combination of different sized/shaped particles could result in ideal absorption of the majority of the solar spectrum. Allotting this with the stability of a polymer leads to potential solids or solutions that could work as a solar absorber. Tests were also performed to determine whether or not UV-C irradiation during synthesis effects the characteristics of silver nanoparticles, in particular the absorbance. Successful synthesis of silver nanoparticle …
High Current Table-Top Setup For Femtosecond Gas Electron Diffraction, 2017 University of Nebraska-Lincoln
High Current Table-Top Setup For Femtosecond Gas Electron Diffraction, Omid Zandi, Kyle J. Wilkin, Martin Centurion
Martin Centurion Publications
We have constructed an experimental setup for gas phase electron diffraction with femtosecond resolution and a high average beam current. While gas electron diffraction has been successful at determining molecular structures, it has been a challenge to reach femtosecond resolution while maintaining sufficient beam current to retrieve structures with high spatial resolution. The main challenges are the Coulomb force that leads to broadening of the electron pulses and the temporal blurring that results from the velocity mismatch between the laser and electron pulses as they traverse the sample. We present here a device that uses pulse compression to overcome the …
Microwave Assisted Dipole-Dipole Transitions, 2017 Ursinus College
Microwave Assisted Dipole-Dipole Transitions, Jacob T. Paul
Physics and Astronomy Honors Papers
We explore this two photon assisted transition through computational and numerical analysis of possible energy levels. We calculate the matrix elements of the energy transition in detail discussing constants and the quantum mechanical possibilities of energy exchanges in these systems.
The goal is to better understand the energy exchange, so that moving forward we can control it. This paper covers the theoretical ends to controlling the energy transition by the way of two photon assisted transitions. The energy transitions take place between a dipole-dipole interaction, and a microwave photon.
Using An Atomic Molecular Optics Laboratory For Undergraduate Research And Mentoring Of Physics Students In Georgia, 2017 Georgia College and State University
Using An Atomic Molecular Optics Laboratory For Undergraduate Research And Mentoring Of Physics Students In Georgia, Matthew P. Dallas
Georgia College Student Research Events
Using an Atomic Molecular Optics Laboratory for Undergraduate Research and Mentoring of Physics Students in Georgia
An Atomic and Molecular Optical (AMO) Physics research lab is an excellent tool to train and mentor undergraduate students in advanced laboratory techniques. Students gain valuable basic experience in experimental designs, data acquisition techniques, working with high precision optical equipment, building electronics, and working in the machine shop. The current project is building and testing an enclosure for the diode laser to reduce sound and vibrational interference. In addition, we are developing and evaluating a new, more compact laser cavity which is 3d printed. …