Physical Sciences and Mathematics Commons^™

A Comparative Study Of The Structural Features And Kinetic Properties Of The Mofe And Vfe Proteins From Azotobacter Vinelandii, Miguel Alejandro Pabon Sanclemente

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Biological nitrogen fixation is accomplished in the bacterium Azotobacter vinelandii by means of three metalloenzymes: The molybdenum, vanadium, and iron-only nitrogenase. The knowledge regarding biological nitrogen fixation has come from studies on the Mo-dependent reaction. However, the V- and Fe-only-dependent reduction of nitrogen remains largely unknown.

By using homology modeling techniques, the protein folds that contain the metal cluster active sites for the V- and Fe-only nitrogenases were constructed. The models uncovered similarities and differences existing among the nitrogenases regarding the identity of the amino acid residues lining pivotal structural features for the correct functioning of the proteins. These differences, …

Sonication Assisted Synthesis Of Oligomannosides, Christabel Tomla Tanifum

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Oligomannosides prevalently exist as cell surface antigens. They play important roles in diseases such as viral infection and cancer, and they have been shown to be useful as candidates for vaccines. HIV, one of the most devastating modern diseases, has a high content of mannose sugars on its envelope glycoprotein gp120. Oligomannosides of the HIV virus, also called Man9, which are found on the glycoprotein gp120, have been shown to play a protective role for the HIV virus, shielding highly conserved protein domains of gp120 from proteolytic attacks. Thus gp120 plays an important role in HIV infection of cells, being …

Fluvial Systems Tied Together Through A Common Base Level: The Geomorphic Response Of The Dirty Devil River, North Wash Creek, And The Colorado River To The Rapid Base Level Drop Of Lake Powell, Adam L. Majeski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fluvial adjustment to base level change has its roots in the fundamental concepts of geomorphology. This thesis explores the rate of erosion and sedimentation on the Colorado and Dirty Devil rivers and North Wash Creek under the current base level changes related to the drawdown conditions of Lake Powell. Through cross section and long profile resurveys, the current state of each system is captured and added to the historic record of sedimentation in Lake Powell. All three systems are generally forming narrow and deep incised channels driven by the rapid rate of base level fall. Cross sections that deviate from …

On The Applicability Of Genetic Algorithms To Fast Solar Spectropolarimetric Inversions For Vector Magnetography, Brian J. Harker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The measurement of vector magnetic fields on the sun is one of the most important diagnostic tools for characterizing solar activity. The ubiquitous solar wind is guided into interplanetary space by open magnetic field lines in the upper solar atmosphere. Highly-energetic solar flares and Coronal Mass Ejections (CMEs) are triggered in lower layers of the solar atmosphere by the driving forces at the visible ``surface'' of the sun, the photosphere. The driving forces there tangle and interweave the vector magnetic fields, ultimately leading to an unstable field topology with large excess magnetic energy, and this excess energy is suddenly and …

Rayleigh-Lidar Observations Of Mesospheric Gravity Wave Activity Above Logan, Utah, Durga N. Kafle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Rayleigh-scatter lidar operated from Utah State University (41.7°N, 111.8°W) for a period spanning 11 years ― 1993 through 2004. Of the 900 nights observed, data on 150 extended to 90 km or above. They were the ones used in these studies related to atmospheric gravity waves (AGWs) between 45 and 90 km. This is the first study of AGWs with an extensive data set that spans the whole mesosphere. Using the temperature and temperature gradient profiles, we produced a climatology of the Brunt-Väisälä (buoyancy) angular frequency squared, N² (rad/s)². The minimum and maximum values of N …

Object Trajectory Estimation Using Optical Flow, Shuo Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Object trajectory tracking is an important topic in many different areas. It is widely used in robot technology, traffic, movie industry, and others. Optical flow is a useful method in the object tracking branch and it can calculate the motion of each pixel between two frames, and thus it provides a possible way to get the trajectory of objects. There are numerous papers describing the implementation of optical flow. Some results are acceptable, but in many projects, there are limitations. In most previous applications, because the camera is usually static, it is easy to apply optical flow to identify the …

A Computational Geometry Approach To Digital Image Contour Extraction, Pedro J. Tejada

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We present a method for extracting contours from digital images, using techniques from computational geometry. Our approach is different from traditional pixel-based methods in image processing. Instead of working directly with pixels, we extract a set of oriented feature points from the input digital images, then apply classical geometric techniques, such as clustering, linking, and simplification, to find contours among these points. Experiments on synthetic and natural images show that our method can effectively extract contours, even from images with considerable noise; moreover, the extracted contours have a very compact representation.

Mesospheric Atmospheric Gravity Wave Properties Derived From Rayleigh-Scatter Lidar Observations Above Logan, Utah, Durga Kafle

Posters

Approximately 900 nights of observations with a Rayleigh-scatter lidar at Utah State University’s Atmospheric Lidar Observatory (41.7°N, 111.8°W, 1.47 km above sea level), spanning the 11-year period from late 1993 through 2004, have been reduced to derive nighttime temperature and relative density profiles between 45 and 90 km. Of these, 150 profiles that extend to 90 km or above were used in this work, which is based mainly on relative density data with 3-km altitude resolution and 1-hour temporal resolution. This is, we believe, the first comprehensive study of monochromatic gravity waves using Rayleigh-Scatter lidar observations extending through the entire …

Algebraic Computing Tools In General Relativity: Energy-Momentum Tensors And Exact Solutions To The Einstein Field Equations, Sydney Joanne Chamberlin

Undergraduate Honors Capstone Projects

Maple is a mathematical software program containing packages of tools that may be used in making difficult computations. The Tensor sub-package of Maple's Differential Geometry package is a collection of commands used for making tensor computations on manifolds. We present a series of new tools for the Tensor package. Included with these tools are new commands to compute objects of geometric and physical interest -energy-momentum tensors, matter field equations, the Bel-Robinson tensor, etc. -along with tools to compute the geometric properties of these objects. Additionally, an electronic database of exact solutions to the Einstein field equations has been created for …

Investigations Of Variable Importance Measures Within Random Forests, Andrew C. Merrill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Random Forests (RF) (Breiman 2001; Breiman and Cutler 2004) is a completely nonparametric statistical learning procedure that may be used for regression analysis and. A feature of RF that is drawing a lot of attention is the novel algorithm that is used to evaluate the relative importance of the predictor/explanatory variables. Other machine learning algorithms for regression and classification, such as support vector machines and artificial neural networks (Hastie et al. 2009), exhibit high predictive accuracy but provide little insight into predictive power of individual variables. In contrast, the permutation algorithm of RF has already established a track record for …

Novel Growth Of Ingaas/Gaas Nanostructures By Molecular Beam Epitaxy, Dong Jun Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation presents an extensive study of the epitaxial growth mechanism by a novel growth method. This novel growth method was developed at Utah State University and is a modification of the Stranski-Krastanov (S-K) growth mode. Our new growth method consists of a two-step process, low temperature growth and high temperature annealing. During low temperature growth, diffusion is minimized, resulting in the deposition of a pseudomorphic epilayer. During high temperature annealing, diffusion is induced from the pseudomorphic epilayer, resulting in the transformation of the epilayer into nanostructures. Benefits of this novel growth method are a significantly smaller segregation and suppressed …

A Geologic And Hydrochemical Investigation Of The Suitability Of Central Utah's Navajo Sandstone For The Disposal Of Saline Process Water And Co2, Kevin L. Randall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Salt water is produced from the Ferron Sandstone Member of the Mancos Shale in central Utah as part of the production of coalbed methane (CBM) and is disposed of by injection predominantly into the Navajo Sandstone between 4,500 feet to 7,300 feet and is considered to be a hazardous waste. Local government agencies are concerned about the potential impacts on shallow groundwater because of this disposal method.

Water samples were gathered from four shallow water-supply wells, and nine salt water disposal (SWD) wells to compare hydrochemistries as an indicator of potential mixing. Shallow water-supply wells are likely recharged by local …

Modeling The Evolution Of Insect Phenology With Particular Reference To Mountain Pine Beetle, Brian P. Yurk

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is likely to disrupt the timing of developmental events (phenology) in insect populations in which development time is largely determined by temperature. Shifting phenology puts insects at risk of being exposed to seasonal weather extremes during sensitive life stages and losing synchrony with biotic resources. Additionally, warming may result in loss of developmental synchronization within a population, making it difficult to find mates or mount mass attacks against well-defended resources at low population densities. It is unknown whether genetic evolution of development time can occur rapidly enough to moderate these effects.

The work presented here is largely motivated …

Watershed-Scale Analysis Of Riparian Buffer Function, Molly Van Appledorn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The ability of riparian buffers to filter undesirable nutrients from upland sources has long been recognized as an important ecosystem service for maintaining or improving water quality, and as a result, many land management strategies have been built around the preservation or restoration of buffer zones. Newly derived flow-path metrics have shown great promise as a way to assess riparian buffer function at the watershed scale but a thorough investigation of metric performance was necessary. The goals of this study were to: 1) test the independence of flow-path metrics from traditional metrics using a spatially extensive, independent sample of watersheds, …

A Methodology To Design Pipelined Simulated Annealing Kernel Accelerators On Space-Borne Field-Programmable Gate Arrays, Jeffrey Michael Carver

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increased levels of science objectives expected from spacecraft systems necessitate the ability to carry out fast on-board autonomous mission planning and scheduling. Heterogeneous radiation-hardened Field Programmable Gate Arrays (FPGAs) with embedded multiplier and memory modules are well suited to support the acceleration of scheduling algorithms. A methodology to design circuits specifically to accelerate Simulated Annealing Kernels (SAKs) in event scheduling algorithms is shown. The main contribution of this thesis is the low complexity scoring calculation used for the heuristic mapping algorithm used to balance resource allocation across a coarse-grained pipelined data-path. The methodology was exercised over various kernels with different …

Geochemical Provenance Of Clastic Sedimentary Rocks In The Western Cordillera: Utah, Colorado, Wyoming, And Oregon, John Aaron Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sedimentary rocks are an important source of information about previous orogenic conditions and the composition of which may describe the evolution of provenance and tectonic setting. Many factors influence sediment composition, namely, source rock composition, chemical weathering, climate, transport burial, and diagenesis. As the sediment composition changes through time, the geochemical characteristics of the sediment can be used to understand its geologic history.

The geochemical characteristics of clastic sedimentary rocks are useful in determining the depositional setting and its associated provenance. Although many different studies have used geochemical discriminants to evaluate provenance and tectonic settings, none have used a defined …

Symmetry Analysis Of General Rank-3 Pfaffian Systems In Five Variables, Francesco Strazzullo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this dissertation we applied geometric methods to study underdetermined second order scalar ordinary differential equations (called general Monge equations), nonlinear involutive systems of two scalar partial differential equations in two independent variables and one unknown and non-Monge-Ampere Goursat parabolic scalar PDE in the plane. These particular kinds of differential equations are related to general rank-3 Pfaffian systems in five variables. Cartan studied these objects in his 1910 paper. In this work Cartan provided normal forms only for some general rank-3 Pfaffian systems with 14-, 7-, and 6-dimensional symmetry algebra.

In this dissertation we provided normal forms of all general …

Frames And Ways Of Knowing: Key Considerations For Policy Responses To Climate Risk And Vulnerability, Helen Ingram, Joanna Endter-Wada

Environment and Society Faculty Publications

This paper argues that resilience and adaptability in face of climate change is largely dependent upon the ways in which framing occurs and knowledge is produced and diffused in particular communities and contexts. Climate change problems are contextual, multifaceted and complex, engendering wide variation in social sense making and invoking different formulations of facts and relevant knowledge. Transferring and translating information among different ways of knowing and transforming ways of knowing so that they are more inclusive and accepted is critical to adaptability and resilience. Examples from the American West and Latin America illustrate that only when multiple frames and …

Landscape Limnology: Nutrient Fluxes & Biotic Stability In Complex Mountain Watersheds, Wayne A. Wurtsbaugh, Michelle Kang, Dave M. Epstein

Watershed Sciences Faculty Publications

No abstract provided.

First Observation Of An Undular Mesospheric Bore In A Doppler Duct, J. Fechine, C. M. Wrasse, H. Takahashi, A. F. Medeiros, P. P. Batista, B. R. Clemesha, L. M. Lima, D. C. Fritts, B. Laughman, Michael J. Taylor, Pierre-Dominique Pautet, M. G. Mlynczak, J. M. Russell

All Physics Faculty Publications

On 1 October 2005, during the SpreadFEx campaign, a distinct mesospheric bore was observed over S˜ao Jo˜ao do Cariri (7.4 S, 36.5 W), Brazil by using airglow allsky imagers. The event appeared both in the OI5577 and OH emissions, forming a well extended wave front which was followed by short waves from behind. Simultaneous wind and temperature data obtained by the meteor radar and the TIMED/SABER satellite instrument revealed that the bore event occurred during the Doppler ducting condition in the emission layers.

Core-Level Spectroscopy Of The Pd/W(110) Interface: Evidence Of Long-Range Pd-Island—Winteractions At Submonolayer Coverages, D. Mark Riffe, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang

All Physics Faculty Publications

We have measured W 4f_7/2 core-level photoemission spectra from W(1 1 0) in the presence of Pd overlayers for coverages up to ∼1 pseudomorphic monolayer (ML). At coverages close to 0.05 ML a striking change in the W core-level spectrum is observed, which we interpret as indicating a long-range lateral effect of 2D Pd islands upon the W electronic structure in both the first and second W layers. As the coverage increases the long-range effect weakens and finally vanishes near 0.85 ML. Above this coverage the W spectra are typical for a W-based bimetallic interface, with the first-layer …

Simultaneous Observation Of Ionospheric Plasma Bubbles And Mesospheric Gravity Waves During The Spreadfex Campaign, H. Takahashi, Michael J. Taylor, Pierre-Dominique Pautet, A. F. Medeiros, D. Gobbi, C. M. Wrasse, J. Fechine, M. A. Abdu, I. S. Batista, E. R. De Paula, J. A.H. Sobral, D. Aruda, D. C. Fritts

All Physics Faculty Publications

During the Spread F Experiment campaign, under NASA Living with a Star (LWS) program, carried out in the South American Magnetic Equator region from 22 September to 8 November 2005, two airglow CCD imagers, located at Cariri (7.4° S, 36.5° W, geomag. 11° S) and near Brasilia (14.8° S, 47.6° W, geomag. 10° S) were operated simultaneously and measured the equatorial ionospheric bubbles and their time evolution by monitoring the airglow OI 6300 intensity depletions. Simultaneous observation of the mesospheric OH wave structures made it possible to investigate the relationship between the bubble formation in the ionosphere and the gravity …

Rayleigh-Lidar Determinations Of The Vertical Wavelength Of Mesospheric Gravity Wave, Joe R. Slansky, Durga N. Kafle, Vincent B. Wickwar

Posters

Atmospheric structures have been observed in the Rayleigh lidar data acquired between 1993 and 2004 at Utah State University (USU). The observations pertain to the density and temperature in the mesosphere between 45 and 90 km altitude. The structures referred to arise from monochromatic Atmospheric Gravity Waves (AGWs). Previous analysis of these data have searched for and found a spectrum with a peak in the vertical wavelength 12–16 km. It has been suggested by other researchers using other types of data that there may be another peak in the spectrum at shorter wavelengths. For this study the lidar data were …

Rayleigh-Lidar Observations Of Mesospheric Instabilities, Gabriel C. Taylor, Durga N. Kafle, Vincent B. Wickwar

Posters

From 1993 to 2004 the Utah State University Rayleigh lidar, known as the USU green laser, collected 900 nights of data from the mesosphere (45-90 km). From these observations profiles of relative neutral densities and absolute temperatures were derived. Usually, the atmosphere is horizontally stratified with a balance between gravitational and pressure forces. When this balance is perturbed, it leads to the generation of buoyancy or “gravity” waves. An example of these is clear air turbulence, which can have dramatic effects on airplanes. As these waves propagate upward, the decrease in atmospheric density and conservation of energy combine to give …

Development Of A Cubesat Pico-Satellite, Phillip Anderson, Jan Sojka

Posters

The CubeSat Project was developed by California Polytechnic State University (CalPoly) and Stanford University in order to provide launch opportunities to universities previously unable to afford access to space. Today, it provides low-cost launch opportunities to students, government, and businesses. The CubeSat program is able to provide these low-cost launch opportunities by defining a common form factor and design guidelines. All satellites conforming to the regulations are able to be deployed from a standard, flight-proven deployment system called a PPOD. By adhering to the prescribed form factor and safety requirements, necessary documents and export licenses are more easily obtained. CalPoly …

Photoelectric Charging By Ultraviolet Light Of A Lunar Dust Simulant In A Microgravity Environment, Troy Munro, Andrew Fassmann

Posters

A microgravity experiment to test the electrostatic behavior of a lunar dust simulant being charged through the photoelectric effect will expand understanding of the charging characteristics of dust particles and may lead to a possible mitigation solution. With a design based upon Robert Millikan’s oil-drop experiment, this experiment is designed to observe the interactions of a lunar dust simulant without the conflicting effect of a dominant gravitational force. The dust particles will be charged by means of a lamp capable of photon energies necessary to emit electrons by the photoelectric effect. In the presence of an axial electric field, the …

Microgravity Experiments For The Iss, Justin Koeln, Jan Sojka

Posters

The Get Away Special (GAS) team is a microgravity research team known for leading Utah State University to the impressive distinction of flying more experiments in space than any other university in the world. The following experiments were designed by the GAS team after receiving the opportunity to develop and experiment to be performed by a Space Flight Participant aboard the International Space Station (ISS).

Space Research Projects For The International Space Station, Kyle Hodgson

Posters

Space Italian Dressing Experimental Setup (SIDES) examines the dynamics of fluid segregation between fluids of differing densities. While in space the fluids will not undergo buoyant or convective forces, thus isolating the affects of separation due to density and molecular forces. The experiment will serve as an outreach experiment in addition to gleaning scientific data; mixtures are a topic of study in the 5th grade curriculum.

The objective of International Paper Airplanes in Space (IPAS) is to excite children about space research by giving them a chance to take part in it. IPAS includes collecting paper airplanes made by elementary-school …

Ringworld: Travellers' Tales From Saturn, Shane L. Larson

Public Talks

No abstract provided.

Hearing Voices In The Dark: Probing The Gravitational Wave Cosmos With Lisa, Shane L. Larson

Colloquia and Seminars

No abstract provided.