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Articles 1 - 30 of 1774

Full-Text Articles in Physical Sciences and Mathematics

Corn And Soybean Response To Wastewater-Recycled Phosphorus Fertilizers, Shane Ylagan Dec 2020

Corn And Soybean Response To Wastewater-Recycled Phosphorus Fertilizers, Shane Ylagan

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

The ability to recycle phosphorus (P) from wastewaters could provide a sustainable, continuous source of P that might also help protect surface water quality from P enrichment. The mineral struvite (MgNH4PO4·6H2O) is an understudied material that can be created from Pcontaining wastewater and has been shown to have agricultural fertilizer value. The objective of this study was to evaluate the effects of electrochemically precipitated struvite (ECST), chemically precipitated struvite (Crystal Green; CG), diammonium phosphate (DAP), monoammonium phosphate (MAP), rock phosphate (RP), and triple super phosphate (TSP) on corn (Zea mays) and soybean (Glycine max) response in a 79-day greenhouse ...


Design Of Submicron Structured Guided-Mode-Resonance Near-Infrared Polarizer, Marzia Zaman May 2020

Design Of Submicron Structured Guided-Mode-Resonance Near-Infrared Polarizer, Marzia Zaman

Theses and Dissertations

The objective of this research is to design a larger submicron linear polarizer in the near-infrared wavelength range with a wide bandwidth which can be fabricated using the conventional thin-film microfabrication technology to reduce cost. For this purpose, a gold (Au) wire-grid transmission-type transverse-magnetic (TM) polarizer and a silicon (Si) wire-grid reflection-type TM polarizer, were designed using the guided-mode-resonance filter. The Au wire-grid TM polarizer of 700nm grating width and 1200nm grating period has 95% transmittance at 2400nm, more than 1000nm resonance peak bandwidth, and an extinction ratio (ER) of around 300 with a moderated level of sidebands. The 700nm ...


Wayne E. Sabbe Arkansas Soil Fertility Studies 2019, Nathan A. Slaton May 2020

Wayne E. Sabbe Arkansas Soil Fertility Studies 2019, Nathan A. Slaton

Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.


Construction Of A Hyperspectral Imager Using 3d-Printed And Off-The-Shelf Components, Joshua Moorhouse May 2020

Construction Of A Hyperspectral Imager Using 3d-Printed And Off-The-Shelf Components, Joshua Moorhouse

Mechanical Engineering Undergraduate Honors Theses

The Arkansas Center for Space and Planetary Sciences is working in collaboration with the Mechanical Engineering department to create a relatively cheap and modifiable hyperspectral imager. It is constructed using 3D-printed and off-the-shelf components from Edmund Optics and Amazon. The iteration created in this paper delivers spectrograms in the visible spectrum. The long-term goals of the camera are to create hyperspectral images from these spectrograms and to advance the imager into the infrared and near-infrared spectra. This imager is being developed to be used in the Arkansas Center for Space and Planetary Sciences environmental test chambers to further the scientific ...


Effect Of Charged Lipids On The Ionization Behavior Of Glutamic Acid Containing Transmembrane Helices, Brooke Nunn May 2020

Effect Of Charged Lipids On The Ionization Behavior Of Glutamic Acid Containing Transmembrane Helices, Brooke Nunn

Chemistry & Biochemistry Undergraduate Honors Theses

Transmembrane proteins make up critical components of living cells. Protein function can be greatly impacted by the charged state of its respective components, the side chains of amino acid residues. Thus far, in the lipid membrane, little is known about the properties of residues such as glutamic acid. To explore these properties, I have included glutamic acid in a suitable model peptide-lipid system for fundamental biophysical experiments. Within the system, I have placed a glutamic acid residue instead of leucine in the L14 position of the helical hydrophobic peptide GWALP23 (acetyl-GGALWLALALALAL14ALALWLAGA-amide). Substitutions of glutamine and aspartic acid serve ...


Hydrodynamic Instability Simulations Using Front-Tracking With Higher-Order Splitting Methods, Dillon Trinh May 2020

Hydrodynamic Instability Simulations Using Front-Tracking With Higher-Order Splitting Methods, Dillon Trinh

Mathematical Sciences Undergraduate Honors Theses

The Rayleigh-Taylor Instability (RTI) is an instability that occurs at the interface of a lighter density fluid pushing onto a higher density fluid in constant or time-dependent accelerations. The Richtmyer-Meshkov Instability (RMI) occurs when two fluids of different densities are separated by a perturbed interface that is accelerated impulsively, usually by a shock wave. When the shock wave is applied, the less dense fluid will penetrate the denser fluid, forming a characteristic bubble feature in the displacement of the fluid. The displacement will initially obey a linear growth model, but as time progresses, a nonlinear model is required. Numerical studies ...


Utilization Of Recycled Filament For 3d Printing For Consumer Goods, Alexa Peterson May 2020

Utilization Of Recycled Filament For 3d Printing For Consumer Goods, Alexa Peterson

Apparel Merchandising and Product Development Undergraduate Honors Theses

The 3D printing market has been used in a wide variety of manufacturing industries including textile and apparel. Many consumers can now own a personal 3D printer at home for recreational printing. There are even websites dedicated to 3D printing patterns made by consumers. However, the materials used in the 3D printing process pose a problem for the environment due to their plastic-based nature. 3D printing is a layered process with each layer being printed depending on the layer below it for strength and stability. During the 3D printing process, great amounts of waste are produced as a result of ...


On The Explanation And Implementation Of Three Open-Source Fully Homomorphic Encryption Libraries, Alycia Carey May 2020

On The Explanation And Implementation Of Three Open-Source Fully Homomorphic Encryption Libraries, Alycia Carey

Computer Science and Computer Engineering Undergraduate Honors Theses

While fully homomorphic encryption (FHE) is a fairly new realm of cryptography, it has shown to be a promising mode of information protection as it allows arbitrary computations on encrypted data. The development of a practical FHE scheme would enable the development of secure cloud computation over sensitive data, which is a much-needed technology in today's trend of outsourced computation and storage. The first FHE scheme was proposed by Craig Gentry in 2009, and although it was not a practical implementation, his scheme laid the groundwork for many schemes that exist today. One main focus in FHE research is ...


A Capacitive Sensing Gym Mat For Exercise Classification & Tracking, Adam Goertz May 2020

A Capacitive Sensing Gym Mat For Exercise Classification & Tracking, Adam Goertz

Computer Science and Computer Engineering Undergraduate Honors Theses

Effective monitoring of adherence to at-home exercise programs as prescribed by physiotherapy protocols is essential to promoting effective rehabilitation and therapeutic interventions. Currently physical therapists and other health professionals have no reliable means of tracking patients' progress in or adherence to a prescribed regimen. This project aims to develop a low-cost, privacy-conserving means of monitoring at-home exercise activity using a gym mat equipped with an array of capacitive sensors. The ability of the mat to classify different types of exercises was evaluated using several machine learning models trained on an existing dataset of physiotherapy exercises.


Investigating Machine Learning Techniques For Gesture Recognition With Low-Cost Capacitive Sensing Arrays, Michael Fahr Jr. May 2020

Investigating Machine Learning Techniques For Gesture Recognition With Low-Cost Capacitive Sensing Arrays, Michael Fahr Jr.

Computer Science and Computer Engineering Undergraduate Honors Theses

Machine learning has proven to be an effective tool for forming models to make predictions based on sample data. Supervised learning, a subset of machine learning, can be used to map input data to output labels based on pre-existing paired data. Datasets for machine learning can be created from many different sources and vary in complexity, with popular datasets including the MNIST handwritten dataset and CIFAR10 image dataset. The focus of this thesis is to test and validate multiple machine learning models for accurately classifying gestures performed on a low-cost capacitive sensing array. Multiple neural networks are trained using gesture ...


Applying Imitation And Reinforcement Learning To Sparse Reward Environments, Haven Brown May 2020

Applying Imitation And Reinforcement Learning To Sparse Reward Environments, Haven Brown

Computer Science and Computer Engineering Undergraduate Honors Theses

The focus of this project was to shorten the time it takes to train reinforcement learning agents to perform better than humans in a sparse reward environment. Finding a general purpose solution to this problem is essential to creating agents in the future capable of managing large systems or performing a series of tasks before receiving feedback. The goal of this project was to create a transition function between an imitation learning algorithm (also referred to as a behavioral cloning algorithm) and a reinforcement learning algorithm. The goal of this approach was to allow an agent to first learn to ...


Speech Processing In Computer Vision Applications, Nicholas Waterworth May 2020

Speech Processing In Computer Vision Applications, Nicholas Waterworth

Computer Science and Computer Engineering Undergraduate Honors Theses

Deep learning has been recently proven to be a viable asset in determining features in the field of Speech Analysis. Deep learning methods like Convolutional Neural Networks facilitate the expansion of specific feature information in waveforms, allowing networks to create more feature dense representations of data. Our work attempts to address the problem of re-creating a face given a speaker's voice and speaker identification using deep learning methods. In this work, we first review the fundamental background in speech processing and its related applications. Then we introduce novel deep learning-based methods to speech feature analysis. Finally, we will present ...


An Exploration Of Methods For Classifying Air-Written Letters From The Spanish Alphabet, Manuel Serna-Aguilera May 2020

An Exploration Of Methods For Classifying Air-Written Letters From The Spanish Alphabet, Manuel Serna-Aguilera

Computer Science and Computer Engineering Undergraduate Honors Theses

The ability to recognize human activity, especially air-writing, is an interesting challenge as one could identify any letter from many languages. I intend to investigate this problem of air-writing, but with the added twist of including the following letters from the Spanish alphabet: Á, É, Í, Ó, Ú, Ü, and Ñ. With this new alphabet, I set out to see what kinds of classifiers work best and on what kinds of data, since letters can be represented in multiple ways.

My tracking system will consist of a regular camera and a subject who will draw with a brightly colored marker ...


Identifying Privacy Policy In Service Terms Using Natural Language Processing, Ange-Thierry Ishimwe May 2020

Identifying Privacy Policy In Service Terms Using Natural Language Processing, Ange-Thierry Ishimwe

Computer Science and Computer Engineering Undergraduate Honors Theses

Ever since technology (tech) companies realized that people's usage data from their activities on mobile applications to the internet could be sold to advertisers for a profit, it began the Big Data era where tech companies collect as much data as possible from users. One of the benefits of this new era is the creation of new types of jobs such as data scientists, Big Data engineers, etc. However, this new era has also raised one of the hottest topics, which is data privacy. A myriad number of complaints have been raised on data privacy, such as how much ...


Dependency Mapping Software For Jira, Project Management Tool, Bentley Lager May 2020

Dependency Mapping Software For Jira, Project Management Tool, Bentley Lager

Computer Science and Computer Engineering Undergraduate Honors Theses

Efficiently managing a software development project is extremely important in industry and is often overlooked by the software developers on a project. Pieces of development work are identified by developers and are then handed off to project managers, who are left to organize this information. Project managers must organize this to set expectations for the client, and ensure the project stays on track and on budget. The main block in this process are dependency chains between tasks. Dependency chains can cause a project to take much longer than anticipated or result in the under utilization of developers on a project ...


Irrigation Design In Montana: Accommodating Varying Water Accessibility Across The Continental Divide., John Garrett Lampson May 2020

Irrigation Design In Montana: Accommodating Varying Water Accessibility Across The Continental Divide., John Garrett Lampson

Biological and Agricultural Engineering Undergraduate Honors Theses

The design work performed in this project was conducted over two summers (2018, 2019) of internship experience with the Natural Resources Conservation Service (NRCS) across the state of Montana. The first summer’s design work was based out of Glendive, MT, in Dawson County, approximately 50 kilometers from the North Dakota border. The second summer was in Missoula, MT, in Missoula County, near the Idaho border. The two areas differ significantly in topography, weather, and water availability with the main separating geographic influence being the Rocky Mountains.

This paper focuses on the design process and requirements for two farms located ...


Design Of A Shallow-Aero Ebb And Flow Hydroponics System And Associated Educational Module For Tri Cycle Farms, Julie Halveland May 2020

Design Of A Shallow-Aero Ebb And Flow Hydroponics System And Associated Educational Module For Tri Cycle Farms, Julie Halveland

Biological and Agricultural Engineering Undergraduate Honors Theses

Tri Cycle Farms, whose main mission is to reduce food insecurity in their community, is a non- profit urban farm in Fayetteville, Arkansas. The “Tri” in their name refers to the three parts of their foundation: giving a third of their yield to volunteers, giving a third to local food pantries, and selling a third to sustain the farm and demonstrate the economy of local food production. They want to expand on the third part and have a vision of building a hydroponic greenhouse with the intention that it will create more crops to sell and give, as well as ...


On The Seismic Performance Of Skewed Special Moment Frame Reduced Beam Section Connections, Damaso Daniel Dominguez May 2020

On The Seismic Performance Of Skewed Special Moment Frame Reduced Beam Section Connections, Damaso Daniel Dominguez

Theses and Dissertations

Special Moment Frames (SMFs) are frequently used in high seismic areas for architecturally constrained designs, as they provide lateral system stiffness without the use of braces which often obstruct views and architectural features. Reduced beam section (RBS) connections are popular SMF connection details developed following the Northridge earthquake to limit brittle fractures within connection welds. Current American Institute of Steel Construction (ASIC) provisions (i.e. AISC 341-16) provide prequalified SMF RBS connection details (including welding requirements); however, all prequalified details only consider orthogonal connections between the beam and column. This dissertation investigates the effect of adding skew within SMF RBS ...


The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty May 2020

The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty

Theses and Dissertations

Eutrophication of surface waters not only impacts the environment but also water treatment processes, the most significant of which is from the effects of algae. During peak algal growth in many southern U.S. reservoirs, inflows that bring nutrients are at an annual minimum, and phosphorus released from bed-sediments is trapped in the hypolimnion. Littoral areas, described as the most productive zone of the lake, may be a possible source of phosphorus that fuels algal growth in the reservoir. I studied an isolated shallow cove in the War Eagle Creek arm of Beaver Lake in Northwest Arkansas to measure, quantify ...


Extracting Social Network From Literary Prose, Tarana Tasmin Bipasha Dec 2019

Extracting Social Network From Literary Prose, Tarana Tasmin Bipasha

Theses and Dissertations

This thesis develops an approach to extract social networks from literary prose, namely, Jane Austen’s published novels from eighteenth- and nineteenth- century. Dialogue interaction plays a key role while we derive the networks, thus our technique relies upon our ability to determine when two characters are in conversation. Our process involves encoding plain literary text into the Text Encoding Initiative’s (TEI) XML format, character name identification, conversation and co-occurrence detection, and social network construction. Previous work in social network construction for literature have focused on drama, specifically manually TEI-encoded Shakespearean plays in which character interactions are much easier ...


Sentiment Analysis, Quantification, And Shift Detection, Kevin Labille Dec 2019

Sentiment Analysis, Quantification, And Shift Detection, Kevin Labille

Theses and Dissertations

This dissertation focuses on event detection within streams of Tweets based on sentiment quantification. Sentiment quantification extends sentiment analysis, the analysis of the sentiment of individual documents, to analyze the sentiment of an aggregated collection of documents. Although the former has been widely researched, the latter has drawn less attention but offers greater potential to enhance current business intelligence systems. Indeed, knowing the proportion of positive and negative Tweets is much more valuable than knowing which individual Tweets are positive or negative. We also extend our sentiment quantification research to analyze the evolution of sentiment over time to automatically detect ...


Detecting Differentially Co-Expressed Gene Modules Via The Edge-Count Test, Anne Gratius Lin Dec 2019

Detecting Differentially Co-Expressed Gene Modules Via The Edge-Count Test, Anne Gratius Lin

Theses and Dissertations

Background

Gene expression profiling by microarray has been used to uncover molecular variations in many different diseases. Complementary to conventional differential expression analysis, differential co-expression analysis can identify gene markers from the systematic and granular level. There are three aspects for differential co-expression network analysis, including the network global topological comparison, differential co-expression cluster identification, and differential co-expressed genes and gene pair identification. To date, most of the methods available still rely on Pearson’s correlation coefficient despite its nonlinear insensitivity.

Results

Here we present an approach that is robust to nonlinearity by using the edge-count test for differential co-expression ...


Contrasting Geometric Variations Of Mathematical Models Of Self-Assembling Systems, Michael Sharp Dec 2019

Contrasting Geometric Variations Of Mathematical Models Of Self-Assembling Systems, Michael Sharp

Theses and Dissertations

Self-assembly is the process by which complex systems are formed and behave due to the interactions of relatively simple units. In this thesis, we explore multiple augmentations of well known models of self-assembly to gain a better understanding of the roles that geometry and space play in their dynamics. We begin in the abstract Tile Assembly Model (aTAM) with some examples and a brief survey of previous results to provide a foundation. We then introduce the Geometric Thermodynamic Binding Network model, a model that focuses on the thermodynamic stability of its systems while utilizing geometrically rigid components (dissimilar to other ...


Observable Persistent Effects Of Habitat Management Efforts In The Ozark Highlands After 10 Years, Maxwell Carnes-Mason Dec 2019

Observable Persistent Effects Of Habitat Management Efforts In The Ozark Highlands After 10 Years, Maxwell Carnes-Mason

Theses and Dissertations

I investigated the lasting impacts of a management plan designed to improve oak regeneration and benefit wildlife in the Ozark Highlands in Madison, Co., AR. To assess the efficacy of the management plan, I used variables relevant to the success and establishment of oak trees. Controlled burns and selective logging were used to thin the canopy, increase ground level productivity, and increase the abundance of small mammals. I used measurements of overstory and understory densities, light availability, and the density of mice in the genus Peromyscus across time to look at the lasting impacts of management. Different treatment plots were ...


Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster Dec 2019

Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster

Theses and Dissertations

The Eastern Collared Lizard (Crotaphytus collaris) has experienced extensive population declines over the past half century in the Ozark Mountains. Previous research suggests that glade habitat degradation through woody vegetation encroachment is an important factor resulting in population declines. In this dissertation I used information on time-energy budgets to investigate the link between habitat degradation and shifts in life history traits likely resulting in population declines of Eastern Collared Lizards (Crotaphytus collaris) in the Ozarks. In chapter one, I addressed the influence of dense woody vegetation encroachment on age-specific growth, body size, body condition and reproduction of C. collaris in ...


Aglycon Modifications Of Ipomoeassin F: Synthetic Route Development And Analog Synthesis To Enable Further Sar Studies, Eric Barber Dec 2019

Aglycon Modifications Of Ipomoeassin F: Synthetic Route Development And Analog Synthesis To Enable Further Sar Studies, Eric Barber

Theses and Dissertations

The ipomoeassin family of resin glycosides were discovered to have a high potency against numerous cancer cell line, with ipomoeassin F being the most potent among the family of natural products. Interestingly, one of the few differences between ipomoeassin F and the other compounds is the length of the fatty-acid derived aglycon. As the mechanism of action for this family of resin glycosides is unknown and didn’t have any significant COMPARE correlation with the recorded anticancer agents in the National Cancer Institute (NCI), further SAR studies are needed. Drawing on the differences between ipomoeassin F and the other ipomoeassins ...


Rotational Tuning Of Transmembrane Helix Properties Based On The Precise Placements Of Aromatic And Charged Residues, Matthew J. Mckay Dec 2019

Rotational Tuning Of Transmembrane Helix Properties Based On The Precise Placements Of Aromatic And Charged Residues, Matthew J. Mckay

Theses and Dissertations

Designed model transmembrane peptides and oriented 2H and 15N solid-state nuclear magnetic resonance (NMR) spectroscopy were used to analyze how simple sequence modifications can influence peptide structure, behavior and dynamics as well as for determining the pKa of glutamic acid at the membrane interface. The GW5,19ALP23 (acetyl-GGALW(LA)6LWLAGA-amide) peptide framework adopts a well-defined tilted orientation in lipid bilayers (DLPC, DMPC and DOPC) and undergoes low amounts of dynamic motion. The sequence was initially modified by moving the Trp residues outwards to positions 4 and 20. This new sequence GW4,20ALP23 (acetyl-GGAW(AL)7AWAGA-amide) displays high amounts of signal ...


Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity, Ricardo Raphael Lopez Romo Dec 2019

Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity, Ricardo Raphael Lopez Romo

Theses and Dissertations

Noble metal nanoparticles and two-dimensional (2D) transition metal dichalcogenide (TMD) crystals offer unique optical and electronic properties that include strong exciton binding, spin-orbital coupling, and localized surface plasmon resonance. Controlling these properties at high spatiotemporal resolution can support emerging optoelectronic coupling and enhanced optical features. Excitation dynamics of these optical properties on physicochemically bonded mono- and few-layer TMD crystals with metal nanocrystals and two overlapping spherical metal nanocrystals were examined by concurrently (i) DDA simulations and (ii) far-field optical transmission UV-vis spectroscopic measurements. Initially, a novel and scalable method to unsettle van der Waals bonds in bulk TMDs to prepare ...


Understanding And Controlling Lithium Microstructure During Electroplating For Energy Applications, Yang Tian Dec 2019

Understanding And Controlling Lithium Microstructure During Electroplating For Energy Applications, Yang Tian

Theses and Dissertations

Lithium-ion batteries are reaching the specific theoretical capacity limit, while lithium metal batteries are regarded as the ideal energy storage system for the next generation “beyond lithium-ion” battery systems. The lithium metal anode is considered as the “Holy grail” of anodes due to its relatively low electrochemical potential (-3.04 V vs SHE) and high theoretical capacity (3860 mAh g-1). However, the application of lithium metal anodes is hindered because of significant reaction between metallic lithium and electrolytes, as well as uneven electro-plating, which leads to dendrite formation, causing safety problems.

The kinetic parameters of Li ions such as diffusion ...


Surface Modification Of Pvdf Membranes For Treating Produced Waters By Direct Contact Membrane Distillation, Zahra Anari Dec 2019

Surface Modification Of Pvdf Membranes For Treating Produced Waters By Direct Contact Membrane Distillation, Zahra Anari

Theses and Dissertations

Direct contact membrane distillation is a promising unit operation for treating hydraulic fracturing flow back and produced water. However, while a hydrophobic membrane is essential to prevent the passage of water from the feed to the permeate side, fouling by dissolved organic species can compromise membrane performance and result in wetting of the membrane pores. Here four monomers, hydroxyethylmethacrylate, acrylic acid, 1-vinyl-3-allylimidazolium bromide, and 1-vinyl-3-hexylimidazolium bromide have been grafted from the surface of a PVDF membrane. The modified and base membranes were tested in a direct contact membrane distillation system. All membranes were challenged with real produced water. In addition ...