# Thesis/Capstone Archive

 Year: All Years 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1954 1953 1952 1951 1950 1948 1940 1939 1938 1936 1935 1934 1933 Advisor: All Advisors Allred, David D Anderson, Brian E Ballif, Jae R Barnett, J Dean Bass, Robert W Bergeson, Scott D Berrondo, Manuel Campbell, Branton J Chesnel, Karine Marguerite Christensen, Clark G Colton, John S Davis, Robert Clinton Decker, Daniel L Dibble, William E Dixon, Dwight R Dudley, J Duane Durfee, Dallin S Eastmond, E. John Ellsworth, John E Evenson, William E Eyring, Carl F. Fletcher, Harvey J Jr Gardner, Andrew L Gardner, John H Gee, Kent L Hales, Richard W. Hales, Wayne B hall, H Tracy Hansen, H Kimball Harrison, Bertrand Kent Hart, Grant W Hart, Gus L Hatch, Dorian Maurice Hess, Bret C Hill, Max W Hintz, Eric G B Hirschmann, Eric W Hoyt, Gordon D. Jeffery Kraczek, Elizabeth Jane Jensen, Gary Lee Joner, Michael DeLoss Jones, Douglas Emron Jones, Steven E Knight, Larry V Larson, Everett G. Lawler, Margaret J Leishman, Timothy Ward Lewis, James P Marshall, Milton Mason, Grant W McNamara, D Harold Migenes Gaetan, Victor Miller, Martin L Moody, Joseph Ward Neilsen, David W Neilsen, Tracianne Beesley Nelson, H Mark Palmer, E Paul Peatross, Justin B Peterson, Bryan G Powers, Nathan D Ragozzine, Darin A Rasband, Neil Rees, Lawrence Brent Rogers, Vern C. Sommerfeldt, Scott D Spencer, Ross Loren Stephens, Denise Catherine Stokes, Harold T Strong, William J Taylor, Benjamin Joseph Thomas, Derek C Transtrum, Mark Kenneth Turley, Robert Steven Van Huele, Jean-Francois S Vanfleet, Howard B Vanfleet, Richard R Ware, Michael J
Bryan Andrews (Capstone, April 2019, Advisor: )

Abstract

During the SAE International Collegiate Series Baja Competition Oregon 2018, various failures in driver control systems occurred resulting in poor performance in dynamic events. These failures were analyzed, and weaknesses were identified in the 2018 BYU Baja vehicle, including the design of the pedals, steering shaft, and suspension components. An improved design was developed by iteration, analyzed for strength using computational and finite element analysis, and field tested for validation. Results of field testing indicated increased capability of redesigned components, which were integrated into the 2019 BYU Baja vehicle. During the SAE Baja California 2019 Competition, no failures were observed in the redesigned components.

Camille Baird (Senior Thesis, April 2019, Advisor: Robert Davis )

Abstract

Porous micro-resonators show promising results for applications in chemical and bio-sensing. Rings and disks resonating in the wine-glass mode or radial contour mode have been designed and fabricated using a highly tunable microfabrication process to undergo further testing for quality factors and viability for sensing applications in fluid environments. Narrow anchors from the resonating structure to mounted pads have been placed at nodal points of the modes of vibration to reduce clamping losses during testing.

Jacob Barker (Senior Thesis, March 2019, Advisor: Justin Peatross )

Abstract

A focused intense laser pulse can rip multiple electrons from atoms. At low density,the liberated electrons move freely in the laser ﬁeld in response to the Lorentz force. The movement of a charged particle causes electromagnetic radiation to scatter out of the focus. In our lab, we study these laser-particle interactions by looking at the scattered electromagnetic radiation. As the laser intensity increases, electrons can reach relativistic speeds as they oscillate. Few people have intuition for this complex motion and radiation. I developed a computer simulation that animates these interactions in a physically realistic manner. I discuss the physics of these interaction and the development of the simulation. I present several animations of scenarios similar to our experiments

Sam Bellows (Senior Thesis, April 2019, Advisor: Timothy Leishman )

Abstract

Directivity measurements of human speech reveal important characteristics of sound radiation and are useful in a variety of applications. Previous work in speech directivity has used different approaches; for this work, the directivity factors and indices of speech were measured using both a single and multiple-capture scanning system with human subjects. Analysis in the spherical harmonic domain helped to show important relationships between the different techniques as well as to simplify relations between measured frequency-response functions and the corresponding directivity factor and index functions. The high-resolution results show that while the directivity of human speech is omnidirectional at low frequencies, it becomes more directional at higher frequencies. Furthermore, diffraction lobes play a significant role in the directivity of human speech.

Abstract

Spectroscopic observations from the Dominion Astrophysical Observatory of the Cepheid X Cyg show that the star underwent a temperature shift and phase transition sometime between 2013 and 2014. As follow-up work, we conducted a photometric campaign to monitor X Cyg and a collection of 40 other Cepheids, measuring their temperature via a set of Ha filters in addition to the Johnson V filter. While phasing observations in the V filter reproduced clear light curves, Ha light curves were far less successful. The greatest hindrance to properly measuring Ha indices was likely poor signal-to-noise in the narrow Ha filter; the 8-inch telescope used may simply be unable to collect enough light. Accumulating more data, however, would likely reduce scatter and tighten up the results.

Alex Cahoon (Capstone, April 2019, Advisor: Karine Chesnel )

Abstract

The Surface Magneto-Optical Kerr Effect (SMOKE) magnetometer is an instrument used to measure the out-of-plane magnetization of thin films made of ferromagnetic materials using polarized visible light. It does this by taking advantage of the Kerr effect which is a magnetic-optical interaction where the polarization of the light reflected from a magnetic surface is rotated approximately proportionally to the amount of magnetization in the material. We use the instrument to map hysteresis loops in ferromagnetic thin film multilayers by applying a varying external magnetic field to the sample while simultaneously measuring the polarization rotation. My project has consisted of upgrading the physical SMOKE apparatus: we have improved the mechanical stability and introduced new features that will allow us to alter the incident angle between the sample and the polarized light, as well as give us the ability to translate samples so that we can study different sections of the samples without having to remount them.

Jared Carlson (Senior Thesis, May 2019, Advisor: Mark Transtrum )

Abstract

Superconducting Radio Frequency (SRF) cavities are important components of particle accelerators. SRF cavity performance is limited by a maximum allowed applied magnetic field, known as the superheating field ($H_{\rm sh}$) at which magnetic vortices spontaneously enter the material and cause the superconducting material to quench. Previous work has calculated the theoretical maximum field a superconductor can withstand. However, this calculation assumed a perfectly smooth surface with no material inhomogeneities or surface roughness. Real world cavities are polycrystalline (typically Nb or Nb$_3$Sn) and exhibit surface defects near grain boundaries. Cavity preparation methods also lead to material inhomogeneities. I use the time-dependent Ginzburg-Landau theory and finite element methods to model the role of surface defects and material inhomogeneities in magnetic vortex nucleation. Results show the amount by which Hsh is reduced depends on the concentration of impurities as well as the physical dimensions of the defect. Reducing the size of grain boundaries and material inhomogeneities found therein has the potential to significantly increase SRF cavity performance.

Damyn Chipman (Capstone, April 2019, Advisor: )

Abstract

Computational models that accurately describe the physics in fluid domains are essential in the design process of aircraft. These models are used as tools to quickly design, model, test, and optimize aircraft. However, many current mathematical models are too computationally taxing. Optimization of many of these Eulerian, or mesh-based, methods is infeasible, due to the high wall time for each call to the model. Our approach is to use Lagrangian methods, which have the potential of reduced wall time and increased numerical accuracy. The Vortex Particle Method (VPM) is a Lagrangian formulation of the vorticity form of the Naiver-Stokes (NS) equations put together by Alvarez et al [1]. While the VPM is capable of solving the NS equations in a field, boundary conditions must be imposed separately. The purpose of this thesis is to present an approach to introducing boundary information through the calculation of a vortex sheet on a surface required to induce the no-slip boundary condition. The resulting vorticity is then introduced to the vorticity field through the solution of a diffusion equation. This Vortex Sheet Boundary (VSB) Method is presented and verified, and the results are discussed.

Mylan Ray Cook (Masters Thesis, April 2019, Advisor: Kent Gee )

Abstract

[Abstract]

Rudger Dame (Capstone, April 2019, Advisor: )

Abstract

Some planetary surfaces are found to be extremely smooth when viewed remotely by radar. The question this study addresses is if radar images can be used together with field roughness calculations of smooth surfaces on Earth to better quantify the smoothness of planetary surfaces. Using the Danakil Depression as an analog site for smooth planetary surfaces, images of multiple sites within the depression were used to build 3D models of the different geologically flat regions (e.g. salt flats). Roughness calculations based on the 3D models and radar images of the area were made and compared. These two methods of calculating the terrain roughnesses, in all but a few cases, gave similar results. Our study shows that this method of analyzing 3D models of the surfaces to obtain a roughness values, can quantify the degree of flatness of a playa surface and be generally correlated with radar remote sensing observations of the surface.

Elisabeth Frischknecht (Senior Thesis, April 2019, Advisor: Denise Stephens )

Abstract

Herbig Ae/Be (HAeBe) stars are classified as 2-10 solar mass pre-main sequence stars with protoplanetary disks. As a result, they are excellent candidates for observing exoplanets in the formative stages of their evolution. By constructing and then subtracting a model Point Spread Function from object frames, an image of the protoplanetary disk and any planets located within it is obtained. This technique was used to analyze archival Hubble Space Telescope images of HAeBe object HD100546, which is known to host at least one planet (HD100546b) that has been detected at near-infrared wavelengths by other telescopes. The supposed detection of HD100546b is likely a false positive, but it is possible that the planet is still located within the data and may be detectable upon further research.

Josh Gregg (Senior Thesis, June 2019, Advisor: Brian Anderson )

Abstract

Nonlinear resonant ultrasound spectroscopy (NRUS) is a method that can be used for detecting the amount of microcracking in structures. NRUS detects global damage in a sample by measuring shifts in resonance frequencies that depend on excitation amplitude and correspond to nonlinear elastic properties of the material. NRUS measurements typically are excited with a piezoelectric transducer, but here the application of an electromagnetic transducer is explored as an alternative. The electromagnetic transducer, unlike a single piezoelectric, allows selective excitation of longitudinal, torsional, and bending vibrations in a rod-shaped sample. Measurement of the nonlinear properties of the sample for each type of vibration is therefore possible. This electromagnetic technique involves gluing a coil of wire onto the end of a rod sample and placing it in a magnetic field. By controlling which part of the coil is inside the strongest region of the magnetic field, the principle direction of the driven oscillations in the rod can be controlled. Both piezoelectric and electromagnetic excitation techniques are tested by measuring the nonlinear elastic parameter, alpha_E, of Berea sandstone. The electromagnetic technique was shown to measure a 30% higher mean value for alpha_E than the piezoelectric technique.

Sarah Hill (Senior Thesis, April 2019, Advisor: Scott Bergeson )

Abstract

Dual-species ultra-cold plasmas in our laboratory expand too quickly for measurements at times longer than 30 microseconds. We plan to solve this problem by trapping the plasma using a Paul trap. The trap will be loaded by photo-ionizing neutral atoms in a co-located magneto-optical trap. This will enable plasma studies over longer time periods, making it possible to measure the internal interactions within the plasma. In order to use a Paul trap, we need to deliver higher voltages to the trap at radio frequencies. We report the successful construction of a harmonic resonator with a resonant frequency of ω = 2π ×4.0 MHz and a Q-factor of 151. When imperfect impedance matching is included in our measurements, we find that our helical resonator amplifies our radio frequency generator's output voltage by a factor of 120 at the trap.

Daniel Johnston (Capstone, April 2019, Advisor: )

Abstract

Influenza A is responsible for the death of an average of 85 000 people per year in the western hemisphere and the hospitalization of many more. Currently-available anti-influenza drugs were designed to target the M2 proton channel and disrupt the process of viral replication but widespread mutations to the M2 channel have rendered these drugs generally ineffective. In preparation for the event of a flu pandemic a new class of anti-influenza drugs is needed. Copper ions have been shown to successfully block the M2 channel and in this paper several novel compounds are complexed with copper and tested as potential M2 inhibitors via electrophysiology tests and miniplaque assays. The results show that several neutral compounds successfully block mutant and wild type viruses in oocyte studies. However, animal tests show no efficacy. Divalent compounds are shown to be ineffective in all cases. Monovalent compounds are hypothesized to be the best suited to M2 inhibition due to the channel’s design, which is intended to transport monovalent protons. Future studies should include further testing of monovalent copper complexes.

Christian Lambert (Senior Thesis, February 2019, Advisor: Manuel Berrondo )

Abstract

Emergent behavior - behavior exhibited by groups that is not seen in individuals - is a critical part of our world and is difficult to model well. We present a dynamic model where a flock of simulated birds (boids) exists in two dimensions. Each boid has a constant speed and a fixed randomly determined number of neighbors, defined as those boids that influence the direction of its motion (consensus). Modifications of the boids’ flight following a specific algorithm (frustration) during the simulation results in emergent behavior. The flock of boids is mapped to a directed graph. Changing the boids’ neighbors also modifies the graph. Rigorously defined sub-flocks are identified using graph theory. Using a new method of frustration, α turns, we can enhance the emergent behavior exhibited. Analyzing this emergent behavior is done through order parameters that help us understand how ordered the flock or sub-groups of the flock are. Analyzing the mapping of the graph to the flock can expand our understanding of how and when dynamic emergence occurs in this flocking model. This is done by showing how physical the model is in whether the flock splits like we see real flocks of birds doing. Using α turns and the nearest neighbor consensus method we find we have emergent behavior within a specific range of the model parameters.

Eric Lysenko (Senior Thesis, June 2019, Advisor: Traci Neilsen )

Abstract

Seismo-acoustic coupling occurs when seismic wave propagation creates air-borne acoustic signals. Research is ongoing to determine methods to distinguish between sound due to seismo-acoustic coupling and purely air-borne transmission. In a field experiment, we detonated 17-inch balloons filled with a stoichiometric oxy-acetylene mix placed both on and in the ground. We attempted to isolate ground-radiated waves by constructing a portable soundproof box to deaden air-borne sound wave. The box was constructed from mass-loaded vinyl, soundproofing composite board, liquid nails, and green glue. This design incorporated soundproofing through decoupling, absorption, and insulation techniques. Signals observed from a microphone placed in the box are compared with those obtained on microphones outside the box at various heights. The initial blast wave was not evident inside the box. However, the loudest sound measured in the box matches a subsequent portion of signals on microphones near the ground. Testing in a reverberation chamber is done to measure the frequency response in the insertion loss through the box. These results could suggest a viable technique for isolating ground-borne acoustic waves, which could be useful in experiments where calculating the coupling effect is impractical.

Quin McKnight (Senior Thesis, April 2019, Advisor: Scott Bergeson )

Abstract

A multi-laser approach is used in which we correct errors in the atomic spectroscopy that seriously compromised previous measurements by another group [Phys. Rev. A 76, 062505 (2007)].We report precision measurements of the 173Yb 6s6p1Po1(F′=3/2,7/2)transition frequencies. We use a frequency comb to determine the laser frequency. Our work completes a set of isotope- and hyperfine-shift measurements reported in [1], published by our group. The frequency shift between the 6s6p1Po1(F′=32,72)levels is 86.29±0.77 MHz. The uncertainty is dominated by quantum interference effects in the excitation and decay pathways. Appendix A is a summary of notes made on an overheating problem encountered in our laboratory, and a copy of both papers on which I was primary author while completing my undergraduate work included at the end of the thesis.

Jared Miller (Capstone, April 2019, Advisor: Scott Sommerfeldt )

Abstract

There has always been a significant population concerned with achieving the best possible environment for listening to music; but in our world of convenience, people don’t want to have to go to the symphony hall to enjoy such an experience. The research presented here uses active noise control to alter sound produced in a given environment, in order to match a more desirable listening environment. This is done by incorporating a measured acoustic impulse response, representing the desired listening environment, into a filtered-x algorithm. The algorithm adapts until the response in the actual listening space matches the response of the desired listening space. Creating a computational simulation allowed for rigorous testing of the algorithm. Once the algorithm was fine tuned through the simulated testing, it could be applied in a physical system. Initial physical testing shows promising results, so further investigations are recommended.

Wiley Spencer Morgan (PhD Dissertation, April 2019, Advisor: Gus Hart )

Abstract

[Abstract]

Michael Nelson (Senior Thesis, April 2019, Advisor: Lawrence Rees )

Abstract

Frequently, in nuclear physics research, nuclear events are studied using the electrical or optical signals they produce in various materials. Research relating to neutrons has an especially strong need for robust and efficient signal classification algorithms that can be adapted quickly to varying materials and experiment types. Previous methods are considered, and a new graphically-driven software-based pulse shape discrimination approach is proposed. Our implementation of the method is explained in detail. Use of the method at BYU has significantly reduced the time required to begin new neutron-related research projects and adapt to changes in experimental setup. Furthermore, it has dramatically increased user understanding of the pulse classification process, reduced the number of errors made, and helped identify mistakes made in processing previous datasets.

Miriam Packard (Senior Thesis, April 2019, Advisor: Mike Joner )

Abstract

Variable stars, like RR Lyraes, can be useful for determining globular cluster characteristics. The globular cluster NGC 5466 has many RR Lyares in a relatively spacious ﬁeld. The RR Lyraes in the globular cluster NGC 5466 were used to create light curves from data taken using photometry at West Mountain Observatory in Utah. This photometric data is input into a computer program called FITLC, which determines periods and amplitudes by ﬁtting light curve templates to the data. These periods are compared with the periods found in Ferro et al. (2008). Metallicity of the cluster is solved for using three different methods outlined in Jeffery et al. (2011) that also depend on period: the Sarajendini, Alcock, and Bono method. The Alcock method provided metallicity results closest to Ferro et al. (2008) with the average metallicity of [Fe/H] = -2.127437 and a standard deviation of 0.062176.

Paige Price (Capstone, April 2019, Advisor: Dallin Durfee )

Abstract

External cavity diode lasers can mode hop unexpectedly. Based on previous measurements by others in the field, we have theorized that a substantial amount of phase noise occurs when a laser is about to switch modes. By monitoring this phase noise and making necessary adjustments, laser stability could possibly be maintained. We have developed an experiment to measure the phase noise to test our theory and determine the feasibility of this stabilization technique. However, the first step in this process is locking the laser to a reference cavity. The locking system currently being used does not work. This paper outlines the current progress and the steps that will be needed to finish testing whether phase noise increases before a mode hop.

Benjamin Proudfoot (Senior Thesis, April 2019, Advisor: Darin Ragozzine )

Abstract

The dwarf planet (136108) Haumea has an intriguing combination of unique physical properties: near-breakup spin, two regular satellites, and an unexpectedly compact collisional family. While these properties point towards formation by a collision, there is no self-consistent and reasonably probable formation hypothesis that can connect the unusually rapid spin and the low relative velocities of Haumea family members ("Haumeans"). We explore and test the proposed formation hypotheses (catastrophic collision, graze-and-merge, and satellite collision) in detail. We flexibly parameterize the properties of the collision (e.g., the collision location) and use simple models for the unique three-dimensional velocity ejection field expected from each model to generate simulated families. These are then compared to the observed Kuiper Belt Objects using Bayesian parameter inference, including a mixture model that robustly allows for interlopers from the background population. After testing our methodology, we find that the best match to the observed Haumeans is an essentially isotropic ejection field with a typical velocity of 150 m s$^{-1}$. The graze-and-merge formation hypothesis - in which Haumeans are shed due to excess angular momentum - is clearly disfavored because the observed Haumeans are not oriented in a plane. The satellite collision model is also disfavored. Including these new constraints, we present a detailed discussion of the formation hypotheses, including variations, some of which are tested. Some new hypotheses are proposed (a cratering collision and a collision where Haumea's upper layers are "missing") and scrutinized. We do not identify a satisfactory formation hypothesis, but we do propose several avenues of additional investigation. In the process of these analyses, we identify many new candidate Haumeans and dynamically confirm 7 of them as consistent with the observed family. We also confirm that Haumeans have a shallow size distribution and discuss implications for the discovery and identification of new Haumeans.

Matthew Richards (Senior Thesis, April 2019, Advisor: John Colton )

Abstract

Hydrogen gas has been hailed as the fuel of the future. Unfortunately, significant problems with its production, storage, and transportation prevent its widespread use. One possible solution is to make hydrogen gas using ferritin-bound platinum nanoparticles (FBPNs). I studied the optimum time of UV exposure for making FBPNs, and the ability of FBPNs to synthesize hydrogen gas. FBPN samples were made by reacting chemicals under a UV lamp with stirring. I fractioned the FBPN samples using size-exclusion chromatography and the fraction with the FBPNs was identified using spectrophotometry. I tested the protein concentration using the Lowry protein assay and the platinum concentration using ICP-MS. Using these results, the number of platinum nanoparticles per ferritin was calculated. I then used the FBPNs to catalyze hydrogen gas production. The amount of hydrogen gas was tested using TCD-GC. Preliminary results indicate that the optimum time for production of FBPNs is 30 minutes of UV exposure, resulting in 182.7 platinum nanoparticles per ferritin being formed. I successfully synthesized hydrogen gas as well. While difficulties with the LPA make the results tenuous, the methods, with some modification, would allow the quick analysis of other important parameters in this process and should be pursued.

Christoph Schulzke (Senior Thesis, January 2019, Advisor: Justin Peatross )

Abstract

Electrons driven by intense laser fields exhibit nonlinear Thomson scattering. Measuring these radiation patterns has become of interest to many groups including our group at Brigham Young University.The theoretical description of this phenomenon was outlined by Sarachik and Schappert in 1970. The solution for the scattered light involves a numeric integral. They developed an approximation which uses a series of Bessel functions in place of the integral. In this thesis we investigate the efficacy of the Bessel-series approximation to see if gives an advantage over the numerical-integration approach. We find only a modest advantage for certain parameters. Generally, performing the integration numerically is a sensible approach.

Micah Shelley (Senior Thesis, April 2019, Advisor: John Colton )

Abstract

Zinc oxide is a semiconductor with a wide band gap (3.37 eV), allowing for applications in optics and optoelectronics. Historically, stable p-type material has been difficult to create. We report deposition of stable p-type ZnO thin films by rf magnetron sputtering. Arsenic acts as the p-type dopant, and is provided through a base layer of Zn3As2 evaporated onto the substrate. Annealing the samples improves crystal structure. P-type material is confirmed, and material properties are quantified by Seebeck effect, Hall effect, photoluminescence, and x-ray diffraction measurements. We identify the effects of substrate temperature, sputter time, rf power, and plasma gas ratio on the electrical and optical properties of the ZnO:As. Future work to improve the quality of the films produced is discussed.

Alex Spencer (Senior Thesis, April 2019, Advisor: Denise Stephens )

Abstract

Information gained from analyzing exoplanets should answer questions about planetary and solar system formation. At Brigham Young University, the existence of exoplanets are confirmed using the transit detection method. However, information about these objects of interest are shrouded by the telescope’s inherent noise. In order to analyze the desired information, noise reduction procedures must be applied manually through command-line methods. This reduction process is slow and tedious, causing the sought-after data to often go untouched for long periods of time. To circumvent this, a program—called the pipeline—was further developed to perform these procedures automatically. The pipeline calls C-style script files to complete each action automatically, analyzing and responding to the discrepancies in each data set. The pipeline performs noise reduction quickly, consistently, and reliably. When compared to student researchers performing reduction tasks manually, the pipeline displays improvements in the processed data. Most importantly, the pipeline allows student researchers more time to focus on analyzing results or to work on other projects.

Rochelle Steele (Senior Thesis, April 2019, Advisor: Joseph Moody )

Abstract

No astronomer has yet discovered the dwarf galaxies that many Λ Cold Dark Matter (ΛCDM) simulations predict should be abundant within intergalactic voids. Spectroscopic observations are necessary to identify and determine the distances to these galaxies. However, dwarf galaxies are so faint that it is difficult to observe them with spectroscopic methods. We have developed a way to photometrically identify dwarf galaxies and estimate their distance using three narrowband filters centered on the Hα emission line. From this method, the redshift of the Hα emission line can be estimated, which gives the distance to the galaxy. Equivalent width, or strength, of the emission line detected can also be estimated. The line observed must be verified as Hα emission using observations with Sloan broadband filters. We have primarily studied one void, FN8, using these methods and have found 14 candidate dwarf galaxies, which must still be confirmed spectroscopically. The low density of candidate void galaxies rejects the hypothesis that there is a uniform distribution of dwarf galaxies within the void, as suggested by some ΛCDM simulations.

Colter Stewart (Senior Thesis, April 2019, Advisor: John Colton )

Abstract

Zinc oxide (ZnO) is a promising wide band gap semiconductor with applications in ultraviolet optoelectronics. Through a novel sputtering process, our group seeks to create arsenic- doped p-type ZnO. In order to characterize these samples, we must understand the thin evaporated zinc arsenide (Zn3As2) layer in between the sputtered ZnO and our substrates. We characterize these samples by variable-angle spectroscopic ellipsometry (VASE), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Enclosed is a paper our research group has submitted to Optics Express that reports the results of these characterizations; these results show that a five-parameter ellipsometric model is sufficient to find the optical constants for amorphous Zn3As2 samples. Further work needs to be done in order to properly characterize crystalline Zn3As2 samples via ellipsometry.

Nicholas Van Alfen (Senior Thesis, April 2019, Advisor: Joseph Moody )

Abstract

Blazars are active galactic nuclei whose jets point directly at the Earth. By observing the variability in these objects, we can determine their morphology and better understand the distribution of material around a blazar. However, only a handful of blazars are studied regularly. To identify potential candidates for a more in depth study in the future, we observed 192 of the brightest blazars in the northern hemisphere for a year in optical wavelengths with our 16" ROVOR telescope. From our observations, we found 13 blazars displaying a significant level of variability and identified a clear bimodal distribution between smooth an stochastic variability.

Dunn Westhoff (Capstone, June 2019, Advisor: )

Abstract

Solar steam generation has immediate applications in fresh water production. Advances in solar steam generation technology directly benefit developing countries by increasing the availability of fresh water. This paper focuses on the design of a Large-scale Solar-still Fountain (LSF) that will exhibit an advanced solar energy absorber made by Nanjing University’s Dr. Jia Zhu that drastically increases the efficiency of solar steam generation. The LSF will serve as a beautiful public edifice, source of fresh water, and vehicle for increasing the general publics awareness of advanced solar distillation. This increase in public awareness will help pave the way for future research that could potentially raise millions out of chronic drought conditions. This paper describes how I created professional quality 3D renderings of an LSF. Keywords: solar steam generation, solar-still, Blender, fountain