Physical Sciences and Mathematics Commons^™

Magnetic Domain Morphology In [Co(4a)/Pt(7a] Thin Film, Jeremy Metzner

Student Works

A collection of results for multi-layered thin films and their magnetic domains.

Three Ways To Stabilize An Injection Lock, Ethan Welch, Dallin Durfee, Jarom Jackson

Student Works

An injection locked laser can jump out of lock if its current or temperature drifts. By monitoring the spectra or the amplitude of the injection locked laser, we have been able to detect drifts and apply feedback to prevent injection lock from breaking.

Using Frequency Noise Feedback To Satabilize Extended Cavity Diode Lasers For Use In Atomic Physics, Mckinley Pugh, Dallin Durfee

Journal of Undergraduate Research

Diode lasers in particular are useful in atomic physics because they are durable, compact, and relatively inexpensive. Unfortunately diode lasers also have linewidths that are much wider than atomic transitions. One common method to narrow the linewidth of diode lasers is to add a reflection grating outside the laser, creating an extended cavity diode laser (ECDL). While ECDLs are effective at narrowing the linewidth, they also introduce so many variables that affect the wavelength of the laser that small changes in the laser’s environment can cause the laser to mode hop, or jump to an entirely different wavelength.

Characterizing The Design Space Of Oscillatory Biological Networks, Leanne Lunsford, Denise Stephens, Eric Hintz

Journal of Undergraduate Research

Characterizing the relevant parameters of a design space in order to satisfy a specific behavior criterion is an important problem throughout all of science and engineering. In this project we proposed to apply model reduction to the case of biological oscillations involving Michaelis-Menten reactions. By removing irrelevant parameters from a fully connected network we were able to reduce a known problem in systems biology to a more general model. Furthermore, significant progress has been made in applying Manifold Boundary Approximation Method (MBAM) to oscillatory models in systems biology.

Fabrication Of Dye Sensitized Solar Cells Using Native And Non-Native Nanocrystals In Ferritin As The Dye, Alessandro Perego, John Colton

Journal of Undergraduate Research

Dye-sensitized solar cells (DSSCs) present a valuable and sustainable alternative to silicon solar cells. These cells present numerous advantages compered to inorganic photovoltaic systems, such as ability of absorb more sunlight per surface area than standard silicon-based solar panels, DSSCs are also able to work even in low-light conditions such as non-direct sunlight and cloudy skies. Finally, they are economical, easy to manufacture and constructed from abundant and stable resource materials. This makes DSSCs an attractive replacement for current photovoltaic technology. Ferritin (FTN) is a 12 nm diameter spherical protein with an 8 nm hollow interior, which naturally contains iron …

Reverse-Engineering Gene Networks That Can Remember Using The Manifold Boundary Approximation Method, Andrew White, Mark Transtrum

Journal of Undergraduate Research

Observable biological behaviors result from the interactions of microscopic elements, which form complex systems that we can model mathematically. Ideally, mechanistic models should predict a biological system’s behavior without misrepresenting the system’s biochemistry. The method of model reduction known as the Manifold Boundary Approximation Method (MBAM) [2, 3] can help us identify which parts of a model are relevant for explaining a particular behavior. This project applies MBAM to gene transcription networks that exhibit a behavior known as “memory,” the ability to retain cellular decisions to activate or silence genes. We hypothesize that MBAM can help us model the behaviors …

Quantum Dot Band Gap Investigations, John Ryan Peterson

Student Works

Improving solar panel efficiency has become increasingly important as the world searches for cheap renewable energy. Recent developments in the industry have focused on multi-layer cells, some of which use semiconducting dyes to absorb light in place of crystalline solids. In this paper, I characterize various dyes recently synthesized for use in solar panels. These dyes contain semiconducting nanoparticles enclosed primarily by the protein ferritin to limit particle size. The band gaps were measured using either optical absorption spectroscopy or measuring the photoluminescence spectrum, depending on the type of semiconductor. The results indicate that both manganese oxide and lead sulfide …

Modeling Of Acoustic Resonators And Resonator Systems For Use In Passive Noise Control, Matthew Franklin Calton

Theses and Dissertations

Acoustic resonators, such as the Helmholtz and quarter-wave resonator, can be used to attenuate unwanted noise in an enclosed space. Classical formulations can be used to approximate resonator performance for a given resonator configuration, but may lack sufficient accuracy for some applications. This research aims to improve the analytical characterization of resonators to provide better correlation to experimental results. Using higher-order approximations and proper end corrections, more accuracy can be obtained in calculating the impedance and resonance frequency of a single resonator, which will then carry over into the overall configuration of the model. The impedance of a system of …

Improvements To The Two-Point In Situ Method For Measurement Of The Room Constant And Sound Power In Semi-Reverberant Rooms, Zachary R. Jensen

Theses and Dissertations

The two-point in situ method is a technique for measuring the room constant of a semi-reverberant room and the sound power of a source in that room simultaneously using two measurement positions. Using a reference directivity source, where the directivity factor along any given axis of the source has been measured, one is able to use the Hopkins-Stryker equation to measure both the room constant and the sound power level of another source rather simply. Using both numerical and experimental data, it was found that by using generalized energy density (GED) as a measurement quantity, the results were more accurate …

Development, Evaluation, And Validation Of A High-Resolution Directivity Measurement System For Played Musical Instruments, K Joshua Bodon

Theses and Dissertations

A high-resolution directivity measurement system at Brigham Young University has been renovated and upgraded. Acoustical treatments have been installed on the microphone array, professional-grade audio hardware and cabling have been utilized, and user-friendly MATLAB processing and plotting codes have been developed. The directivities of 16 played musical instruments and several loudspeakers have been measured by the system, processed, and plotted. Using loudspeakers as simulated musicians, a comprehensive analysis was completed to validate the system and understand its error bounds. A comparison and evaluation of repeated-capture to single-capture spherical systems was made to demonstrate the high level of detail provided by …

Optically Detected Magnetic Resonance Of Silicon Vacancies In Sic: Predicting Resonance Of Cylindrical Cavities, Kyle Miller, John Colton

Journal of Undergraduate Research

Optically Detected Magnetic Resonance is one method of performing Electron Spin Resonance (ESR) on a material. ESR is used to determine the electron spin lifetime of a material, an important parameter for use in quantum computing. Resonant cavities are conducting containers that are frequently used in ESR to create a strong magnetic field near the sample. As such it is valuable to design a resonant cavity and predict its resonant frequency. Cylindrical cavities modified with dielectric resonators (DRs) are viable for such experiments.

Exploring The Weak Mach Reflection Regime, Kevin Leete, Dr. Kent Gee

Journal of Undergraduate Research

When a shock wave reflects off a rigid surface with certain combinations of incident shock strength and angle, a Mach reflection can occur. This is when portions of the incident and reflected waves merge to create a stronger shock called a Mach stem that travels parallel to the reflecting surface. This phenomenon has been studied extensively for two extreme cases: large outdoor explosions and small, laboratory experiments of weak shocks. The purpose of this project was to design and execute an outdoor experiment where this phenomenon could be observed by microphones as well as high speed video imaging to detect …

High Resolution Shock Capturing On Gpus, Forrest Glines, David Neilsen

Journal of Undergraduate Research

This research project concerns the development simulation code to confirm neutron star mergers as the progenitors of Short Hard Gamma Ray Bursts. Short Hard Gamma Ray Bursts (SHGBs) are short (less than 2 second) high energy bursts that we observe with satellites. Their exact cause has not yet been confirmed, but they are believed to be created by the merging of either two neutron stars or a neutron star falling into a black hole. Neutron stars are ultra dense, highly magnetic, and compact stars at the end of their evolution. In a binary system the stars lose angular momentum to …

Determining The Size Of A Light Source Using The Hanbury Brown And Twiss Effect, Adam Kingsley, Dallin Durfee

Journal of Undergraduate Research

In 1956, Hanbury Brown and Twiss (HBT) published a paper¹ on a method of determining the angular size of a star by comparing the intensities gathered from two detectors. They used this effect by using two photomultiplier tubes and by increasing the distance between them, saw a drop in the correlation between the currents. Because the correlations are made by the interference at the detectors but only the intensity is measured, the effect is sometimes referred to as intensity interferometry.

The idea arose to use the HBT effect to teach undergraduates various principles of light in a lab setting. …

Phase Matching In Laser Generated Harmonics, David Squires, Justin Peatross

Journal of Undergraduate Research

In this mentored research project, we investigated how intense laser light is scattered by samples of gas. In particular, we measured light scattered in non-phase-matched directions perpendicular to the laser beam.

According to classical phase matching, the intensity of light scattered from a sample depends on whether the sample is best approximated as a continuous medium or a collection of discrete emitters (Figure 1). In the former case, as the angle between the phase-matching direction and the radiated harmonic approaches π/2 radians, the intensity of that radiated harmonic light approaches 0. In the latter case, the light intensity reaches …

Porous Cantilevers As Chemical Sensors, Steven Noyce, Robert Davis

Journal of Undergraduate Research

Many chemical sensing methods rely on the binding mechanism of the analyte to create a measurable response, making it difficult to create new sensors quickly, but resonant sensors require only that an analyte be bound and rely on the resulting change in mass to obtain a measurement. Solid resonant microcantilevers, or small vibrating fixed-free beams, are a type of resonant sensor that have shown extremely high sensitivities in vacuum environments. The sensitivity of these cantilevers, however, decreases greatly in fluid environments such as air or water due to fluid damping. We propose that porous microcantilever sensors offers both a ten …

Measuring Frequency Noise For Use In Preventing Mode Hops In Extended Cavity Diode Lasers, Mckinley Pugh, Dallin Durfee

Journal of Undergraduate Research

Diode lasers are useful in physics because they are relatively cheap and robust, they are available in a number of wavelengths, and they are tunable. However, because diode lasers have large bandwidths compared to atomic resonances, a reflection grating is added outside the laser. This creates the extended cavity in extended cavity diode lasers (ECDLs) and forces the lasers to operate at a narrower line width, one acceptable for use in atomic physics. Unfortunately, because the ECDL has many factors trying to control the wavelength of the laser (e.g. temperature, current, grating angel and position) small changes in the lasers …

Systematic Analysis Of Nonlinearities In Complex Models, Alexander Shumway, Mark Transtrum

Journal of Undergraduate Research

Mathematical models are ubiquitous in science. Many models are nonlinear in the parameters and may have dozens to thousands of parameters and make hundreds to thousands of predictions. Analysis and application of these models is thus theoretically complicated and computationally expensive.

The standard method of model analysis is a model-by-model approach that relies on the intuition of expert researchers. Recent research, however, has shown that many models—known as sloppy models—are statistically similar, despite coming from widely varied fields⁴. This suggests the possibility of developing a theory of modeling in place of relying on expert intuition. Our research …

Dual Species Calcium And Ytterbium Magneto Optical Trap, Alexander Erickson, Scott Bergeson

Journal of Undergraduate Research

One area of particular interest in modern physics research is creating a viable fusion system for sustainable energy. Fusion occurs when a high energy plasma is manipulated in such a way that small atoms collide together, combining to create larger atoms and releasing tremendous amounts of harvestable energy. However, there are many theoretical, mathematical, and practical roadblocks to creating a stable fusion experiment. One practical limitation and one mathematical limitation are as follows: practically, much of the energy used to create a fusion-grade plasma ends up in the kinetic energy of the electrons and is lost to the experiment; mathematically, …

Reflectometry Of Aluminum Thin Films In The Vacuum Ultraviolet, Benjamin Smith, R. Steven Turley

Journal of Undergraduate Research

Vacuum Ultraviolet (VUV) is a range of light on the electromagnetic spectrum corresponding to wavelengths from 40 – 280 nm. VUV photons have too much energy to see visibly and are blocked completely by atmosphere. This wavelength range, however, shows promise for applications in space-based exoplanet research telescopes. Specifically, the chemical fingerprints that this light contains can tell us about the composition and formation of exoplanet atmospheres.

Measurement Of The Yb I 1S0-1P1 Transition Frequency At 399 Nm Using An Optical Frequency Comb, Michaela Kleinert, M. E. Gold Dahl, Scott D. Bergeson

Faculty Publications

We determine the frequency of the Yb I ¹S₀-¹P₁ transition at 399 nm using an optical frequency comb. Although this transition was measured previously using an optical transfer cavity [D. Das et al., Phys, Rev. A 72, 032506 (2005)], recent work has uncovered significant errors in that method. We compare our result of 751 526 533.49 ± 0.33 MHz for the ¹⁷⁴Yb isotope with those from the literature and discuss observed differences. We verify the correctness of our method by measuring the frequencies of well-known transitions in Rb and Cs, and by …

Construction Of A 408 Nm Laser System For Use In Ion Interferometry, Lawrence Archibald

Theses and Dissertations

This work reports on the construction of a 408 nm laser system designed to drive stimulated Raman transitions between the F = 4 and F = 5 2 S 1/2 states of 87 Sr + using the 2 P 3/2 state as the intermediate state. This laser system will be used as part of a 87 Sr + ion interferometer. This work also includes a discussion of relevant theory describing the interaction of the ions and laser, along with a calculation of the transition rates as a function of laser power and detuning.

Information Behaviors Of Nuclear Scientists At Korea Atomic Energy Research Institute, Youngchoon Chun, Jiho Yi, Jung-Ran Park, Sangki Choi

Journal of East Asian Libraries

The goal of the study was to analyze the information use behaviors of researchers in the science and technology domain. A survey and interviews were conducted targeting nuclear scientists at the Korea Atomic Energy Research Institute. Study results indicate that the nuclear scientists mainly use the Institute library/information center and Internet portal/search engines during information acquisition. Easy access to information, accuracy, currency and cost are the most critical factors in selecting and obtaining information. The most frequently used database for executing research is the Institute’s electronic library (NUCLIS21) followed by the Citation Index SCOPUS. The results of the study indicate …

Improving Production Of Carbon Nanotube Composites, Dan Broadbent

Faculty Publications

Carbon nanotube (CNT) composites offer great promise for making lighter, thinner and stronger structures. Producing CNT composites, however, can be tricky. The focus of this work is to improve production yields of CNT composites by doing research and development in two areas:

• Research the relationship between ethylene gas concentrations used during CNT growth and yields of usable composite films produced.
• Develop furnace for growing larger CNT samples, which will enable larger sizes and quantities of research product.

Vector Intensity And Holography-Based Acoustic Source Characterization Of A Military Jet Aircraft, Trevor Alden Stout

Theses and Dissertations

The scientific community has employed multiple methods to analyze and describe the jet noise emanating from the turbulent exhaust flow from modern military aircraft engines, with the goal that better characterization of the sound radiation will improve noise reduction efforts. This thesis utilizes three different approaches to characterize the noise source region from a static F-22A Raptor. First, the energy flow field along planes near the aircraft and along an arc is measured using a multidimensional vector intensity probe. The resulting vector intensity maps give a clear indication of the directionality of the noise as a function of frequency at …

Comparing Theory And Experiment For Analyte Transport In The First Vacuum Stage Of The Inductively Coupled Plasma Mass Spectrometer, Matthew R. Zachreson

Theses and Dissertations

The inductively coupled plasma mass spectrometer (ICP-MS) has been used in laboratories for many years. The majority of the improvements to the instrument have been done empirically through trial and error. A few fluid models have been made, which have given a general description of the flow through the mass spectrometer interface. However, due to long mean free path effects and other factors, it is very difficult to simulate the flow details well enough to predict how changing the interface design will change the formation of the ion beam. Towards this end, Spencer et al. developed FENIX, a direct simulation …

A Feasibility Study Of Photometric Reverberation Mapping With Meter-Class Telescopes, Carla June Carroll

Theses and Dissertations

For the past several decades, mass estimates for supermassive black holes hosted by active galactic nuclei (AGN) have been made with the reverberation mapping (RM) technique. This methodology has produced consistent results and has been used to establish several relations that link the characteristics of the host galaxy to the mass of the central black hole. Despite this success, there are less than 50 AGN with black hole masses derived from RM. This low number is generally attributed to the difficulties in coordinating large blocks of telescope time for making simultaneous photometric and spectroscopic observations. Spectroscopic observations also generally require …

Characterization Of Order-Disorder Phase Transition Temperature For Select Nanoparticles, Gregory J. Sutherland

Theses and Dissertations

A method was found for creating ordered nanoparticles whose size and theoretical order-disorder temperature are ideal for study in the TEM. Specifically FePt, NiPt, FeNiPt and AuCu nanoparticles were studied. We were able to show how a nanoparticle's size affects its order-disorder temperature (Tod). When the particles were around 6 nm in diameter there was a shift downward of the Tod of 10-15 percent compared to the bulk. While particles around 10 nm in diameter experienced a downward shift of 0-6 percent compared to the bulk. One can approximate that particles less than 10-15 nm in diameter would show significant …

Dual Species Magneto-Optical Trap, Daniel Woodbury, Scott Bergeson

Journal of Undergraduate Research

In the last several decades, laser cooling has become the primary tool for atomic research and, in our lab, has facilitated the study of ultracold plasma. Using a novel laser cooling setup, we created a vacuum chamber and related hardware for a dual species magneto-optical trap (MOT). The design of the MOT will allow us to improve trapping efficiency and atom density in our plasma, better understand laser cooling and trapping of calcium and ytterbium, and probe their interactions in ultracold hetero-nuclear plasma.

Metal Cnt-M, New Materials And New Approaches To Microfabrication, Richard Vanfleet

Journal of Undergraduate Research

This Mentored Environment Grant (MEG) proposed to explore Carbon Nanotube Templated Microfabrication (CNT-M) approaches that used metal as the infiltration material. We proposed to focus on two specific metal systems; traditionally electrodeposited metals such as nickel and high atomic number metals like tungsten which in many cases cannot be electroplated. Our two objectives were: