Digital Commons Network^™

Effect Of Citric Acid On Slump, Compressive Strength, And Setting Time Of Belitic Calcium Sulfoaluminate Concrete, Israel Aguilar Rosero

Graduate Theses and Dissertations

Belitic calcium sulfoaluminate (BCSA) cement has well established advantages related to fast setting time, fast strength gain, long-term strengths, shrinkage, and sustainability. Due to its fast setting and hardening, this type of cement has historically been used to repair concrete structures, highways, and runways. This work provides much needed guidance on establishing mix design criteria for BCSA cement. Guidance is also given on the effects of set retarders on strength, slump, and setting times. Citric acid and a phosphonic acid-based admixture were tested as retarders for different concrete mixtures. Three studies were performed. In the slump study five different water …

Seismic Loading Effects Within Orthogonally Connected Steel Lateral Force Resisting Systems, Alhussin Faraj Aliwan

Graduate Theses and Dissertations

Steel buildings located within seismically active regions require special design considerations to ensure public safety and prevent collapse during an extreme seismic event. Two commonly used steel systems are special moment frames (SMFs) and buckling-restrained braced frames (BRBFs). When two seismic systems share a common column in an orthogonal configuration (such as at a building corner), design specifications currently consider a 100+30 rule wherein the shared column is designed for 100% fuse demand in one direction, plus 30% fuse demand from the other direction. While this rule has been shown to be reasonable for elastic building response, a few studies …

The Effects Of Multiple Stressors On Stream Communities: The Convergence Of Drought, Nutrient Pollution, And Invasive Species, Robert Joseph Fournier Iii

Graduate Theses and Dissertations

Freshwater systems experience multi-faceted degradation from a variety of ecological and environmental stressors. Three common stressors in these systems, drought, nutrient pollution, and invasive species, have wide-ranging effects on stream population- community- and ecosystem dynamics. We have a broad understanding of how each of these stressors works to influence stream systems independently. However, we still know relatively little about if, and how, these stressors might interact when they co-occur. Though drought is a natural part of many stream systems, all three of these stressors can be exacerbated or facilitated by anthropogenic actions. Accordingly, as human population and resource use continue …

Neogene And Quaternary Events Shaped Diversification And Speciation In Bhutanese Rheophilic Fishes Of The Family Nemacheilidae (Cypriniformes) And Sisoridae (Siluriformes), Karma Wangchuk

Graduate Theses and Dissertations

Biogeography of the Himalayan region [to include the Qinghai-Tibetan Plateau (QTP)] evolved over a ~30M year span, catalyzed by the collision of the Indian and Eurasian plates. The resulting uplift produced major ecological and climatic effects, that in turn drove the diversification of biodiversity. As a result, the QTP is designated as a global biodiversity hotspot particularly vulnerable to cumulative climatic effects, including shrinking distributions, declining numbers, and local extinctions. Understanding how the biodiversity within the Himalaya/ QTP was established and maintained is a necessary first step in prioritizing conservation efforts.

Fishes in global montane regions, such as the Himalaya, …

Static And Dynamical Properties Of Multiferroics, Sayed Omid Sayedaghaee

Graduate Theses and Dissertations

Since the silicon industrial revolution in the 1950s, a lot of effort was dedicated to the research and development activities focused on material and solid-state sciences. As a result, several cutting-edge technologies are emerging including the applications of functional materials in the design and enhancement of novel devices such as sensors, highly capable data storage media, actuators, transducers, and several other types of electronic tools. In the last two decades, a class of functional materials known as multiferroics has captured significant attention because of providing a huge potential for new designs due to possessing multiple ferroic order parameters at the …

Projecting Water Available For Irrigation Use And Identifying Water Supply Stress Under Climate Change Scenarios In Selected U.S. Fruit And Vegetable Production Regions, Andrew Shaw

Graduate Theses and Dissertations

Climate change affects water resources differently across geospatial regions in the United States (U.S). There is a concern of how water availability will be affected by changes in long-term temperature and precipitation patterns, specifically in major production regions for eight fruit and vegetable crops. The effects on surface water available for irrigation use and supply stress in five regions containing 31 Agricultural Statistics Districts (ASDs) were assessed. The Water Supply Stress Index Model was used and modified to project water available for irrigation use across nine climate scenarios driven by historical data, five General Circulation Models, two population scenarios, and …

Comparative Evaluation Of Statistical Dependence Measures, Eman Abdel Rahman Ibrahim

Graduate Theses and Dissertations

Measuring and testing dependence between random variables is of great importance in many scientific fields. In the case of linearly correlated variables, Pearson’s correlation coefficient is a commonly used measure of the correlation strength. In the case of nonlinear correlation, several innovative measures have been proposed, such as distance-based correlation, rank-based correlations, and information theory-based correlation. This thesis focuses on the statistical comparison of several important correlations, including Spearman’s correlation, mutual information, maximal information coefficient, biweight midcorrelation, distance correlation, and copula correlation, under various simulation settings such as correlative patterns and the level of random noise. Furthermore, we apply those …

An Update On The Computational Theory Of Hamiltonian Period Functions, Bradley Joseph Klee

Graduate Theses and Dissertations

Lately, state-of-the-art calculation in both physics and mathematics has expanded to include the field of symbolic computing. The technical content of this dissertation centers on a few Creative Telescoping algorithms of our own design (Mathematica implementations are given as a supplement). These algorithms automate analysis of integral period functions at a level of difficulty and detail far beyond what is possible using only pencil and paper (unless, perhaps, you happen to have savant-level mental acuity). We can then optimize analysis in classical physics by using the algorithms to calculate Hamiltonian period functions as solutions to ordinary differential equations. The simple …

Applications Of Cathodoluminescence In Plasmonic Nanostructures And Ultrathin Inas Quantum Layers, Qigeng Yan

Graduate Theses and Dissertations

Due to the advanced focusing ability, characterization methods based on the electron-beam excitation have been broadly applied to investigate nanomaterials. Structural or compositional information is commonly acquired using electron microscopes. Moreover, taking advantage of the super spatial resolution of the focused electron beam, optical properties of nanomaterials can be also obtained. Herein, general concepts and processes of the interaction between electrons and materials are studied. Two specific optical nanomaterials, including plasmonic nanostructures and semiconductor quantum layers, are investigated by the cathodoluminescence (CL) measurement.

Surface plasmonic resonance can be generated when high-energy electrons strike the interface between the dielectric medium and …

Ppmexplorer: Using Information Retrieval, Computer Vision And Transfer Learning Methods To Index And Explore Images Of Pompeii, Cindy Roullet

Graduate Theses and Dissertations

In this dissertation, we present and analyze the technology used in the making of PPMExplorer: Search, Find, and Explore Pompeii. PPMExplorer is a software tool made with data extracted from the Pompei: Pitture e Mosaic (PPM) volumes. PPM is a valuable set of volumes containing 20,000 historical annotated images of the archaeological site of Pompeii, Italy accompanied by extensive captions. We transformed the volumes from paper, to digital, to searchable. PPMExplorer enables archaeologist researchers to conduct and check hypotheses on historical findings. We present a theory that such a concept is possible by leveraging computer generated correlations between artifacts using …

Gene Set Testing By Distance Correlation, Sho-Hsien Su

Graduate Theses and Dissertations

Pathways are the functional building blocks of complex diseases such as cancers. Pathway-level studies may provide insights on some important biological processes. Gene set test is an important tool to study the differential expression of a gene set between two groups, e.g., cancer vs normal. The differential expression of a gene set could be due to the difference in mean, variability, or both. However, most existing gene set tests only target the mean difference but overlook other types of differential expression. In this thesis, we propose to use the recently developed distance correlation for gene set testing. To assess the …

Argumentation Stance Polarity And Intensity Prediction And Its Application For Argumentation Polarization Modeling And Diverse Social Connection Recommendation, Joseph Winstead Sirrianni

Graduate Theses and Dissertations

Cyber argumentation platforms implement theoretical argumentation structures that promote higher quality argumentation and allow for informative analysis of the discussions. Dr. Liu’s research group has designed and implemented a unique platform called the Intelligent Cyber Argumentation System (ICAS). ICAS structures its discussions into a weighted cyber argumentation graph, which describes the relationships between the different users, their posts in a discussion, the discussion topic, and the various subtopics in a discussion. This platform is unique as it encodes online discussions into weighted cyber argumentation graphs based on the user’s stances toward one another’s arguments and ideas. The resulting weighted cyber …

Predicting The Hydration Free Energy Of Small Alkanes And Alcohols From Custom, Electronic Structure-Based Force Fields, T. Ryan Rogers

Graduate Theses and Dissertations

Mathematical theories reveal the fundamental physics involved in experimentalphenomena. Computer models of such theories are routinely used to corroborate or explain experiments and predict properties of chemical systems. Therefore, an important effort in computational chemistry is the development of more accurate and efficient chemical models. Current-generation models are only beginning to approach experimental-quality predictions of hydration free energies (HFEs).Using computations of quantum mechanical (QM) forces and classical simulations based on these forces, I investigate models to predict several properties of solutes and solutions. This dissertation is a collection of projects exemplifying methods used to gain insight into chemical systems.

Simulations …

Development Of An Effect Size To Classify The Magnitude Of Dif In Dichotomous And Polytomous Items, James D. Weese

Graduate Theses and Dissertations

A standardized effect size for the SIBTEST/POLYSIBTEST procedure is proposed, allowing for Differential Item Functioning (DIF) to be classified with a single set of DIF heuristics regardless of whether data are dichotomous or polytomous. This proposed standardized effect size accounts for both variability in responses and whether participants are included in the SIBTEST/POLYSIBTEST calculations. First, a new set of unstandardized effect size heuristics are established for dichotomous data that are more aligned with Educational Testing Service (ETS) standards using two and three parameter logistic (2PL and 3PL) models. Second, a standardized effect size is proposed and compared to other DIF …

Paleotectonic Investigation By Successive 3d Seismic Horizon Flattening In The Pennsylvanian Interval Of Western Osage County, Oklahoma, Douglas Cooper Mccabe

Graduate Theses and Dissertations

3D seismic and well log data in Western Osage County, Oklahoma, are utilized to evaluate possible intracratonic tectonic signals present in the subsurface stratigraphy of the Cherokee Platform as a result of the regional tectonic events of Pennsylvanian age. These events include: the Wichita, Ouachita, and Arbuckle orogenies, the Nemaha and Ozark Uplifts, and the Southeast Oklahoma Aulacogen. Horizon flattening within 3D seismic volumes allows for identification of paleotectonic structures and syntectonic depositional features, which may be related to the collateral effects of these orogenies on the Cherokee Platform. Identified structures were assigned geologic ages using precision synthetic seismograms tuned …

Framework Grain Composition And Texture Of The Wedington Sandstone Member, Fayetteville Shale, As A Provenance And Sediment Dispersal Indicator For Clastic Depositional Systems Across The Northern Arkansas Structural Platform During The Late Mississippian, Tanner Wayne Corbin

Graduate Theses and Dissertations

The Wedington Sandstone Member of the Fayetteville Shale is a constructive delta complex in the Chesterian section of the Late Mississippian record in Northwest Arkansas. A comparative analysis of framework grain composition between the Wedington and two other stratigraphically proximal Carboniferous sandstones: the Batesville Sandstone (older) and the Basal Atoka-Spiro Sandstone (younger) has addressed three questions: 1) Is there similarity in sediment provenance for the three sandstones? 2) Do these three sandstone units have a similar sediment dispersal vector? 3) What are likely sediment source terrains for the Wedington Sandstone? Wedington samples overwhelmingly plot as quartzarenites with fewer samples plotting …

Stability Of Group Four Monochalcogenides In Water And Air, William Shattuck

Graduate Theses and Dissertations

Previously published works have simulated the behavior of monolayer group IV monochalcogenides and predicted them to have very useful electronic properties. These simulations have also predicted that monolayers of group IV monochalcogenides will degrade quickly when exposed to water, even in extremely low concentrations. We hypothesize that thin samples of these materials will show signs of degradation if left in air and in water for an extended period of time.

Samples of each of the four monochalcogenides (GeS, GeSe, SnS and SnSe) were exfoliated onto clean oxidized silicon substrates. Chemical analysis showed the SnSe samples were contaminated, so they were …

Multi-Proxy Provenance Evaluation Of The Stevens Sandstone, San Joaquin Basin, California, Charles Adam Ball

Graduate Theses and Dissertations

The Stevens sandstone is a prolific hydrocarbon reservoir in the southern San Joaquin Basin that has produced greater than five billion barrels of oil equivalent and represents an important exploration target. The San Joaquin basin has a complex depositional and structural history related to the overprinting of a Mesozoic-Paleogene forearc basin by transtension and transpression along the San Andreas fault system that presently borders the southwestern side of the basin. The Stevens sandstone consists of quartzo-feldspathic, deep-water turbidite deposits and is primarily confined within the subsurface of the southern San Joaquin basin. Due to this mode of deposition and the …

Seismic Expressions Of Paleokarst, Olanrewaju Ayodapo Aboaba

Graduate Theses and Dissertations

Paleokarst are characterized by epigene and/or hypogene processes in their formation and hold significant numbers of hydrocarbons and other natural resources. This dissertation examines worldwide seismic expression of paleokarst; and specifically, the characterization of paleokarst reservoirs developed across the Cherokee Platform, and in the Arkoma Basin, Oklahoma.

Worldwide subsurface paleokarst formations are of Precambrian to Miocene age and found at depths less than 200 m to as great as 8000 m. Karst can be are expressed on seismic records as sinkholes, paleocave collapse, and tower morphologies. Seismic modeling indicates that karst can be modeled and imaged to better understand its …

Data And Assessment Management In Collegiate Recreation, Jeana Carow

Graduate Theses and Dissertations

Collegiate recreation programs and centers typically provide traditional programming space in addition to a range of physical activity spaces and resources, as a valuable part of the student experience. The external pressures of identifying and communicating departmental value and impact on the campus community has resulted in collegiate recreation departments’ use of data to communicate the effectiveness and impact of their work. The purpose of the study was to identify the data collection and assessment management practices of collegiate recreation departments, particularly focusing on the organization of data and assessment strategies as well as data collection, storage, reporting, analyzing, and …

Quantifying The Simultaneous Effect Of Socio-Economic Predictors And Build Environment On Spatial Crime Trends, Alfieri Daniel Ek

Graduate Theses and Dissertations

Proper allocation of law enforcement agencies falls under the umbrella of risk terrainmodeling (Caplan et al., 2011, 2015; Drawve, 2016) that primarily focuses on crime prediction and prevention by spatially aggregating response and predictor variables of interest. Although mental health incidents demand resource allocation from law enforcement agencies and the city, relatively less emphasis has been placed on building spatial models for mental health incidents events. Analyzing spatial mental health events in Little Rock, AR over 2015 to 2018, we found evidence of spatial heterogeneity via Moran’s I statistic. A spatial modeling framework is then built using generalized linear models, …

Optical Properties Of Ultrathin In(Ga)As/Gaas And In(Ga)N/Gan Quantum Wells, Yurii Maidaniuk

Graduate Theses and Dissertations

Recently, structures based on ultrathin quantum wells (QWs) began to play a critical role in modern devices, such as lasers, solar cells, infrared photodetectors, and light-emitting diodes. However, due to the lack of understanding of the formation mechanism of ultrathin QWs during the capping process, scientists and engineers cannot fully explore the potential of such structures. This study aims to investigate how structural parameters of ultrathin QWs affect their emission properties by conducting a systematic analysis of the optical properties of In(Ga)As/GaAs and In(Ga)N/GaN ultrathin QWs. Specifically, the analysis involved photoluminescence measurements combined with effective bandgap simulation, x-ray diffraction, and …

Conditional Distance Correlation Test For Gene Expression Level, Dna Methylation Level And Copy Number, Shanshan Zhang

Graduate Theses and Dissertations

Over the past years, efforts have been devoted to the genome-wide analysis of genetic and epigenetic profiles to better understand the underlying biological mechanisms of complex diseases such as cancer. It is of great importance to unravel the complex dependence structure between biological factors, and many conditional dependence tests have been developed to meet this need. The traditional partial correlation method can only capture the linear partial correlation, but not the nonlinear correlation. To overcome this limitation, we propose to use the innovative conditional distance correlation (CDC), which measures the conditional dependence between random vectors and detect nonlinear relations. In …

Exploring Sediment Compaction In Experimental Deltas: Towards A Meso-Scale Understanding Of Coastal Subsidence Patterns, Samuel Mason Zapp

Graduate Theses and Dissertations

Subsidence in low elevation coastal areas has been extensively researched through direct field measurement, numerical modelling, and stratigraphic reconstruction of ancient sediment deposits. Here I present the first investigation of subsidence due to sediment compaction and consolidation in two laboratory scale river delta experiments. Compactional subsidence rates have never been thoroughly quantified in the experimental setting, though this mechanism is found to be a primary creator of total relative sea level rise which will likely cause coastlines to retreat in the coming years. Spatial and temporal trends in subsidence rates in the experimental setting may elucidate behavior which cannot be …

Models For Data Analysis In Accelerated Reliability Growth, Cesar Alexander Ruiz Torres

Graduate Theses and Dissertations

This work develops new methodologies for analyzing accelerated testing data in the context of a reliability growth program for a complex multi-component system. Each component has multiple failure modes and the growth program consists of multiple test-fix stages with corrective actions applied at the end of each stage. The first group of methods considers time-to-failure data and test covariates for predicting the final reliability of the system. The time-to-failure of each failure mode is assumed to follow a Weibull distribution with rate parameter proportional to an acceleration factor. Acceleration factors are specific to each failure mode and test covariates. We …

Topics In Gravitational Wave Physics, Aaron David Johnson

Graduate Theses and Dissertations

We begin with a brief introduction to gravitational waves. Next we look into the origin of the Chandrasekhar transformations between the different equations found by perturbing a Schwarzschild black hole. Some of the relationships turn out to be Darboux transformations. Then we turn to GW150914, the first detected black hole binary system, to see if the nonlinear memory might be detectable by current and future detectors. Finally, we develop an updated code for computing equatorial extreme mass ratio inspirals which will be open sourced as soon as it has been generalized for arbitrary inclinations.

Effect Of Predictor Dependence On Variable Selection For Linear And Log-Linear Regression, Apu Chandra Das

Graduate Theses and Dissertations

We propose a Bayesian approach to the Dirichlet-Multinomial (DM) regression model, which uses horseshoe, Laplace, and horseshoe plus priors for shrinkage and selection. The Dirichlet-Multinomial model can be used to find the significant association between a set of available covariates and taxa for a microbiome sample. We incorporate the covariates in a log-linear regression framework. We design a simulation study to make a comparison among the performance of the three shrinkage priors in terms of estimation accuracy and the ability to detect true signals. Our results have clearly separated the performance of the three priors and indicated that the horseshoe …

Elucidating Collagen Degradation Synergy Between Col G And Col H From Hathewaya (Clostridium) Histolytica And Identifying Novel Structural Features In Hpt And Rec Domains From Vars Histidine Kinase In V. Alginolyticus, Perry Caviness

Graduate Theses and Dissertations

In this research the mechanisms by which Hathewaya (Clostridia) histolytica collagenases are secreted and work together to degrade collagens are investigated. While H. histolytica collagenases Col G and Col H have similar multi-domain structures the difference in number of and orientation of the domains hint that the two target different regions in collagen. Study small angle x-ray scattering (SAXS) was used to give a low-resolution envelope of full-length Col G and Col H and Col G/Col H non-catalytic domains bound to a collagen-like peptide (mini-collagen). SAXS derived envelopes along with structural information was used to tease out the mechanisms by …

Families Of Homogeneous Licci Ideals, Jesse Keyton

Graduate Theses and Dissertations

This thesis is concered with the graded structure of homogeneous CI-liaison. Given two homogeneous ideals in the same linkage class, we want to understand the ways in which you can link from one ideal to the other. We also use homogeneous linkage to study the socles and Hilbert functions of Artinian monomial ideals.

First, we build off the work of C. Huneke and B. Ulrich on monomial liaison. They provided an algorithm to check the licci property of Artinian monomial ideals and we use their method to characterize when two Artinian monomial ideals can be linked by monomial regular sequences. …

Environmental Influences On Tree-Driven Karst Bedrock Physical Weathering, Cole Robert Jimerson

Graduate Theses and Dissertations

The role of tree roots as stressors that contribute to physical weathering processes and thus soil generation remains an open question in critical zone science. While evidence suggests roots may be able to damage rock by accessing pre-existing fractures, where they can expand due to water uptake or generate forces on rock in response to wind gusts, these processes have not been investigated in temperate karst regions until now. I monitored forces at the root-rock interface for an American elm and Hackberry tree between September 2019 and May 2020. I used piezoelectric force sensors to determine if differences in species, …