Physical Sciences and Mathematics Commons^™

Rainbows In The Grass. Ii. Arbitrary Diagonal Incidence, Charles L. Adler, James A. Lock, Richard W. Fleet

Physics Faculty Publications

We consider external reflection rainbow caustic,,; due to the reflection of light from a pendant droplet where the light rays are at an arbitrary angle with respect to the horizontal. We compare this theory to observation of glare spots from, pendant drops on grass; we also consider the potential application of this theory to the determination of liquid surface tension. (C) 2008 Optical Society of America

The Möbius Geometry Of Hypersurfaces, Michael Bolt

University Faculty Publications and Creative Works

No abstract provided.

Global Irrigation Water Demand: Variability And Uncertainties Arising From Agricultural And Climate Data Sets, Dominik Wisser, Steve Frolking, Ellen M. Douglas, Balazs M. Fekete, Charles Vorosmarty, Andreas H. Schumann

Earth Sciences

Agricultural water use accounts for around 70% of the total water that is withdrawn from surface water and groundwater. We use a new, gridded, global-scale water balance model to estimate interannual variability in global irrigation water demand arising from climate data sets and uncertainties arising from agricultural and climate data sets. We used contemporary maps of irrigation and crop distribution, and so do not account for variability or trends in irrigation area or cropping. We used two different global maps of irrigation and two different reconstructions of daily weather 1963–2002. Simulated global irrigation water demand varied by ∼30%, depending on …

On Existence And Uniqueness Theorem Concerning Time–Dependent Heat Transfer Model, Naji A. Qatanani, Qasem M. Heeh

Applications and Applied Mathematics: An International Journal (AAM)

In this article we consider a physical model describing time-dependent heat transfer by conduction and radiation. This model contains two conducting and opaque materials which are in contact by radiation through a transparent medium bounded by diffuse-grey surfaces. The aim of this work is to present a reliable framework to prove the existence and the uniqueness of a weak solution for this problem. The existence of the solution can be proved by solving an auxiliary problem by the Galerkin-based approximation method and Moser-type arguments which implies the existence of solution to the original problem. The uniqueness of the solution will …

Friends Of The Library Mcnair Scholarship Awards, The Mcnair Team

McNair Scholars Research Journal

No abstract provided.

Factors Related To Success And Participants’ Psychological Ownership In Collaborative Wildlife Management: A Survey Of Sage-Grouse Local Working Groups, Lorien R. Belton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Declines of sage-grouse (Centrocercus spp.) across the western United States have prompted the formation of numerous collaborative stakeholder partnerships, known as local working groups. These voluntary groups create and implement local sage-grouse management plans and projects, often in the hopes that their efforts may help avert a federal Endangered Species designation for the bird. Using a mail survey of participants in 54 local working groups, I examined the importance of psychological ownership in working group dynamics. Psychological ownership is conceptualized as a latent, multidimensional variable consisting of responsibility, control, and caring elements. Multiple regression analysis showed early-stage group success, representative …

Impact Analysis Of System And Network Attacks, Anupama Biswas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Systems and networks have been under attack from the time the Internet first came into existence. There is always some uncertainty associated with the impact of the new attacks. Compared to the problem of attack detection, analysis of attack impact has received very little attention. Generalize and forecasting the kind of attack that will hit systems in future is not possible. However, it is possible to predict the behavior of a new attack and, thereby, the impact of the attack. This thesis proposes a method for predicting the impact of a new attack on systems and networks as well as …

Agent-Organized Network Coalition Formation, Levi L. Barton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents work based on modeling multi-agent coalition formation in an agent organized network. Agents choose which agents to connect with in the network. Tasks are periodically introduced into the network. Each task is defined by a set of skills that agents must fill. Agents form a coalition to complete a task by either joining an existing coalition a network neighbor belongs to, or by proposing a new coalition for a task no agents have proposed a coalition for. We introduce task patience and strategic task selection and show that they improve the number of successful coalitions agents form. …

Darboux Integrability Of Wave Maps Into 2-Dimensional Riemannian Manifolds, Robert Ream

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The harmonic map equations can be represented geometrically as an exterior differential system (EDS), ε. Using this representation we study the harmonic maps from 2D Minkowski space into 2D Riemannian manifolds. These are also known as wave maps. In this case, E is invariant under conformal transformations of Minkowski space. The quotient of ε by these conformal transformations, E/G, is an s=0 hyperbolic system.

The main result of our study is that the prolonged EDS, ε^(k), is Darboux integrable if and only if the prolonged quotient EDS, ε^(k+1), is Darboux integrable. We also find invariants determining …

Decadal-Scale Changes On Coral Reefs In Quintana Roo, Mexico, Thaddeus Allen Nicholls

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In 1988 data on coral reef community composition were collected from two areas, Akumal and Chemuyil, Quintana Roo, Mexico, ranging from 5-35m depth. These areas were revisited in 2005 and data were collected by the same methods and at the same depths as in 1988. Data from 1988 and 2005 were compared to determine if the coral reefs had undergone significant changes, and what specific changes had occurred. Chi-square analysis determined that community composition data collected in 1988 are significantly different from data collected in 2005 at all sites and depths within the categories of corals, gorgonians, sponges, and macroalgae. …

Perceived Crowding And Visitor Support For Use Rationing: A Reanalysis Of Existing Data, Jascha M. Zeitlin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents a reanalysis of data collected between 1999 and 2006 by the Institute for Outdoor Recreation and Tourism (IORT) at Utah State University. These data concern a variety of outdoor recreation sites in Utah, Idaho, and South Dakota, and were collected via intercept, mail, and, to a very limited extent, telephone surveys. Survey instruments contained questions related to visitor perceptions of crowding, overall satisfaction, support for use limits/rationing, and estimates of use density, in addition to other conceptually related factors.

Analyses consisted of multiple regression models for both perceived crowding and visitor support for use limits dependent variables …

The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is to investigate whether it is feasible to use Langmuir probes on pico-satellites flying in low Earth orbit over mid- to low-latitude geographic regions. Following chapters on the expected ionospheric conditions and an overview of Langmuir probe theory, a chapter addressing the difficulties involved with pico-satellite Langmuir probes is presented. Also, the necessary satellite-to-probe surface area requirements in order to achieve confidence in pico-satellite Langmuir probe data, for the orbital regions of interest to this thesis, are stated.

Threat Perception As A Determinant Of Pro-Environmental Behaviors: Public Involvement In Air Pollution Abatement In Cache Valley, Utah, Joshua D. Marquit

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Threat perception related to environmental issues such as air pollution may be a determinant of pro-environmental behaviors. Among the potential threats of air pollution, include the perceived impacts on the psychological, social, and economic wellbeing of a community. Because of rapid increases in population growth, urbanization, and the mountainous landscapes, the American West is extremely susceptible to the adverse impacts of air pollution.

A secondary data analysis was conducted using data from the Air Quality Perception Survey conducted in Cache County, Utah. The survey focused on the public perception of air pollution in Cache County and perceived impact on personal …

Synthetic Complexes Of Relevance To Ni(Ii)-Containing Enzymes, Katarzyna Rudzka

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The work outlined herein presents an investigation of synthetic model complexes of relevance to the active sites of Ni(II)-containing enzymes, particularly urease, glyoxalase I, and acireductone dioxygenase. The research focuses on studying the structural and reactivity features of nickel complexes with biologically relevant substrates. The anion of acetohydroxamic acid is a well-known inhibitor of urease enzymes, including those isolated from Klebsiella aerogenes and Bacillus pasteurii. A precursor to the acetohydroxamate coordination in ureases is proposed to be an interaction between Ni(II) and acetohydroxamic acid. By using a novel supporting chelate ligand capable of secondary hydrogen bonding interactions a novel …

Extending F10.7'S Time Resolution To Capture Solar Flare Phenomena, Ariel O. Acebal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Solar ultraviolet (UV) radiation ionizes the neutral components in the atmosphere, which is partly responsible for the formation of the ionosphere, and contributes to heating of the atmosphere. Solar flares change the solar spectrum at times by several orders of magnitude. These changes modify the Earth's upper atmosphere, causing problems to communication systems and space operations, such as increased satellite drag. Unfortunately, solar UV measurements are limited since they can only be observed with space-based sensors. In order to work around this limitation, the solar radio emissions at a wavelength of 10.7 cm have been used as a proxy for …

Automated Data Type Identification And Localization Using Statistical Analysis Data Identification, Sarah Jean Moody

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research presents a new and unique technique called SÁDI, statistical analysis data identification, for identifying the type of data on a digital device and its storage format based on data type, specifically the values of the bytes representing the data being examined. This research incorporates the automation required for specialized data identification tools to be useful and applicable in real-world applications. The SÁDI technique utilizes the byte values of the data stored on a digital storage device in such a way that the accuracy of the technique does not rely solely on the potentially misleading metadata information but rather …

Modeling The Electrodynamics Of The Low-Latitude Ionosphere, Christian Stephen Wohlwend

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The electrodynamics of the Earth's low-latitude ionosphere is dependent on the ionospheric conductivity and the thermospheric neutral density, temperature, and winds present. This two-part study focused on the gravity wave seeding mechanism of equatorial plasma depletions in the ionosphere and the associated equatorial spread F, as well as the differences between a two-dimensional flux tube integrated electrodynamics model and a three-dimensional model for the same time period. The gravity wave seeding study was based on a parameterization of a gravity wave perturbation using a background empirical thermosphere and a physics-based ionosphere for the case of 12 UT on 26 September …

Factors Affecting Landowner Participation In The Candidate Conservation Agreements With Assurances Program, Kendra Womack

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The United States’ Endangered Species Act of 1973 has been recognized as one of the most powerful laws enacted to protect endangered species in the world. Its protections for animal species extends onto private land, which has in some cases created conflict between the law, its enforcers, and private landowners. The Candidate Conservation Agreements with Assurances (CCAA) program was developed in 1999 to provide a regulatory incentive for private landowners to engage in pro-active conservation for sensitive species to preclude the need for listing under the ESA in the future. Since 1999, however, there have only been 17 CCAAs signed, …

Analysis Of Chemical Bonding In Clusters By Means Of The Adaptive Natural Density Partitioning, Dmitry Yu Zubarev

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Models of chemical bonding are essential for contemporary chemistry. Even the explosive development of the computational resources including, both hardware and software, cannot eliminate necessity of compact, intuitive, and efficient methods of representing chemically relevant information. The Lewis model of chemical bonding, which was proposed eleven years before the formulation of quantum theory and preserves its pivotal role in chemical education and research for more than ninety years, is a vivid example of such a tool. As chemistry shifts to the nanoscale, it is becoming obvious that a certain shift of the paradigms of chemical bonding is inescapable. For example, …

Intergranular Phases In Cyclically Annealed Yba2cu3o7-X And Their Implications For Critical Current Densities, Andrew Peter Clarke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We report changes in the intergranular material and grain morphology of YBa₂Cu₃O_7-x during cyclic anneals between 780 and 980 ºC in oxygen at atmospheric pressure. Two endothermic reactions were detected: (a) the eutectic reaction of YBa₂Cu₃O_7-x with CuO and BaCuO₂ at 900 ºC (enthalpy ∆H_a) and (b) the peritectic reaction of YBa₂Cu₃O_7-x with CuO at 950 ºC (∆H_b). During the first anneal, only reaction (b) is detected, and although it should only occur if there is an excess of CuO, …

A Three-Dimensional, Time-Dependent Circulation Model Of Utah Lake, Eric V. Callister

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spatial and temporal variations of Utah Lake’s flow field were modeled using the Estuary Lake and Computer Model from the Centre for Water Research (CWR-ELCOM) at the University of Western Australia as part of an effort to increase understanding of the lake’s natural processes in order to restore the lake to its pristine, clear-water state and preserve the habitat of the June sucker, an endangered species. The model was validated using temperature measurements taken by sensors in 2007. The water temperature was a strong function of air temperature and incident short wave radiation, and was influenced to a lesser degree …

Two Highly Diverse Studies In Computing: A Vitruvian Framework For Distribution And A Search Approach To Cancer Therapies, Brian G. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Solid cancer tumors must recruit new blood vessels for growth and maintenance. Discovering drugs that block this tumor-induced development of new blood vessels (angiogenesis) is an important approach in cancer treatment. However, the complexity of angiogenesis and the difficulty in implementing and evaluating medical changes prevent the discovery of novel and effective new therapies. This paper presents a massively parallel computational search-based approach for the discovery of novel potential cancer treatments, using a high fidelity simulation of angiogenesis. Discovering new therapies is viewed as multi-objective combinatorial optimization over two competing objectives: minimizing the medical cost of the intervention while minimizing …

A Novel Technique Of Network Auditability With Managers In The Loop, Rian Shelley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Network management requires a large amount of knowledge about the network. In particular, knowledge about used network addresses, access time, and topology is useful. In a network composed of managed devices, much of the data necessary can come from simple network management protocol (SNMP) queries. Other data can come from other databases, or analysis of existing data. In particular, layer-two network topology can be determined by analyzing the mac address forwarding tables of layer-two devices. The layer-two topology can be merged with a layer-three topology to generate a complete topology of the network. This information is useless unless it is …

Approximations To Continuous Processes In Hierarchical Models, Amanda Cangelosi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Models for natural nonlinear processes, such as population dynamics, have been given much attention in applied mathematics. For example, species competition has been extensively modeled by differential equations. Often, the scientist has preferred to model the underlying dynamical processes (i.e., theoretical mechanisms) in continuous-time. It is of both scientific and mathematical interest to implement such models in a statistical framework to quantify uncertainty associated with the models in the presence of observations. That is, given discrete observations arising from the underlying continuous process, the unobserved process can be formally described while accounting for multiple sources of uncertainty ( …

An Evolutionary Approach To Image Compression In The Discrete Cosine Transform Domain, Benjamin E. Banham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper examines the application of genetic programming to image compression while working in the frequency domain. Several methods utilized by JPEG encoding are applied to the image before utilizing a genetic programming system. Specifically, the discrete cosine transform (DCT) is applied to the original image, followed by the zig-zag scanning of DCT coefficients. The genetic programming system is finally applied to the one-dimensional array resulting from the zig-zag scan. The research takes an existing genetic programming system developed for the spatial domain and develops DCT domain functionality. The results from the DCT domain-based genetic programming system are compared with …

Identification Of Subsoil Compaction Using Electrical Conductivity And Spectral Data Across Varying Soil Moisture Regimes In Utah, Jay Murray Payne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subsoil compaction is a major yield limiting factor for most agricultural crops. Tillage is the most efficient method to quickly treat compacted subsoil, but it is also expensive, increases erosion, and accelerates nutrient cycling.

The use of real-time electrical conductivity (EC) and near-infrared (NIR) reflectance values to differentiate compacted areas from uncompacted areas was studied. This method has potential to reduce monetary and time investments inherent in traditional grid sampling and the resultant deep tillage of an entire field. EC and NIR reflectance are both very sensitive to spatial variability of soil attributes.

The objective of this research was to …

Measurement Of Fine Spatial Scale Ecohydrologic Gradients In A Pinyon-Juniper Ecosystem, Matthew David Madsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With the dramatic expansion of pinyon-juniper woodlands over the last century, improved understanding of how these woodlands modify infiltration properties is needed, in order for land managers to make informed decisions on how to best manage their specific resources. However, current methods for measuring soil infiltration are often limited by low sample sizes and high experimental error, due to constraints associated with remote, non agricultural settings. This thesis first presents a scheme for automating and calibrating two commercially available infiltrometers, which allows collection of a large number of precise unsaturated infiltration measurements in a relatively short period of time. Secondly, …

A C To Register Transfer Level Algorithm Using Structured Circuit Templates: A Case Study With Simulated Annealing, Jonathan D. Phillips

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A tool flow is presented for deriving simulated annealing accelerator circuits on a field programmable gate array (FPGA) from C source code by exploring architecture solutions that conform to a preset template through scheduling and mapping algorithms. A case study carried out on simulated annealing-based Autonomous Mission Planning and Scheduling (AMPS) software used for autonomous spacecraft systems is explained. The goal of the research is an automated method for the derivation of a hardware design that maximizes performance while minimizing the FPGA footprint. Results obtained are compared with a peer C to register transfer level (RTL) logic tool, a state-of-the-art …

A Novel Authentication And Validation Mechanism For Analyzing Syslogs Forensically, Steena D.S. Monteiro

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research proposes a novel technique for authenticating and validating syslogs for forensic analysis. This technique uses a modification of the Needham Schroeder protocol, which uses nonces (numbers used only once) and public keys. Syslogs, which were developed from an event-logging perspective and not from an evidence-sustaining one, are system treasure maps that chart out and pinpoint attacks and attack attempts. Over the past few years, research on securing syslogs has yielded enhanced syslog protocols that focus on tamper prevention and detection. However, many of these protocols, though efficient from a security perspective, are inadequate when forensics comes into play. …

Materials Research & Manufacturing Section, Nora Stoeker

Sci-Tech News

No abstract provided.