Physical Sciences and Mathematics Commons^™

Academy Presidents And Institutional Members, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Business Meeting Report (Secretary's And Treasurer's Report), Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Journal Of The Arkansas Academy Of Science - Volume 76, 2022, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Seasonal Testicular Histology And Acystic Lobular Spermatogenesis In The Western Lesser Siren, Siren Intermedia Nettingi (Caudata: Sirenidae), Stanley E. Trauth

Journal of the Arkansas Academy of Science

I investigated the seasonal testicular histology and acystic lobular spermatogenesis in the Western Lesser Siren, Siren intermedia nettingi, from periodic sampling of this salamander over a span of 21 yr (1994-2015) in northeastern Arkansas. My results include the following general findings: 1) the largest testicular lobules occurred primarily in January-February during spermiogenesis and spermatozoa maturation; 2) lobular regression and spermatogenic cell recrudescence were underway by late March; 3) proliferation of secondary spermatogonia in lobules was prominent in May; 4) transformation of secondary spermatogonia into primary spermatocytes occurred by mid-July, and these cells became larger in diameter through increased nuclear …

Distal Urogenital Anatomy In The Male Wood Frog, Lithobates Sylvaticus (Anura: Ranidae), Stanley E. Trauth

Journal of the Arkansas Academy of Science

I investigated the microanatomy of the distal urogenital system of the male Wood Frog (Lithobates sylvaticus) from a small sample (n = 6) collected in northern Arkansas in February 2020. Specifically, my primary objectives were as follows: 1) to focus on the histology of the paired Wolffian (urogenital) ducts caudally from the kidneys to their merging with the urodeum of the cloaca, 2) to reveal the structure of the paired seminal vesicles (sperm storage structures), and 3) to compare epithelial morphologies between the distal urogenital tract and its neighboring distal alimentary tract. This information will promote a clearer …

Physical Characteristics And Classification Of The Large Amplitude Variable Star V1719 Cygni, Ashley Lieber, Logan Siems, Julia Kennefick, Michael Fitzgerald

Inquiry: The University of Arkansas Undergraduate Research Journal

Pulsating stars are used as standard candles which are helpful in determining distances to stellar objects along with the relationship between their period and apparent luminosity. The focus of this study was the variable star, V1719 Cygni, which is often classified as a Delta (δ) Scuti star, but there exists debate that it should be classified as a RR Lyrae star due to its abnormal light curve and similar characteristics between the two variable star categories. Observational data was taken in 2019 using the Las Cumbres Observatory international telescope network. The resulting data were calibrated using comparison stars in the …

Artificial Intelligence System For Automatic Imaging, Quantification, And Identification Of Arthropods In Leaf Litter And Pitfall Samples, Pierce Helton, Khoa Luu, Ashley Dowling

Inquiry: The University of Arkansas Undergraduate Research Journal

It is well known that arthropods are the most diverse and abundant eukaryotic organisms on the planet. Museum and research collections have huge insect accumulations from expeditions conducted over history that contain specimens of both temporal and spatial value, including hundreds of thousands of species. This biodiversity data is inaccessible to the research community, resulting in a vast amount of “dark data”. The primary objective of this study is to develop an artificial intelligence-driven system for specimen identification that greatly minimizes the time and expertise required to identify specimens in atypical environments. Successful development will have profound impacts on both …

Root Phenotyping Of Peptide-Treated Glycine Max, Salem Jackson, Fiona Goggin

Inquiry: The University of Arkansas Undergraduate Research Journal

Plant elicitor peptides (Peps) – endogenous chains of amino acids involved in natural plant defense – have been shown to decrease damage from herbivores and pathogens by inducing an immune response, increasing the emission of volatile organic compounds (VOCS), transcripts, and metabolites. Exogenous treatment of soybean seeds with plant elicitor peptide GmPep3 has been shown to induce these broad-spectrum defenses and offers a new method for increasing crop yield. However, the effects of GmPep3 on indicators of soybean health – root characteristics, growth stages, etc. – have not been fully realized. Using the root-phenotyping platform RhizoVision Explorer, several root traits …

Evaluation Of Nitrous Oxide Emissions From Furrow-Irrigated Rice On A Silt-Loam Soil In Arkansas, Jordan M. Slayden

Graduate Theses and Dissertations

As the number one rice (Oryza sativa)-producing state in the United States, Arkansas also ranks fourth as the largest user of groundwater. Recently, due to the development of drought- resistant hybrid cultivars, the furrow-irrigated rice production system has become an increasingly popular alternative to traditional flood-irrigated production with respect to conserving groundwater and maintaining yield. However, other environmental parameters, like greenhouse gas emissions, specifically nitrous oxide (N2O), have yet to be evaluated under furrow-irrigated rice. The objectives of this study were to i) evaluate the effects of site position (i.e., up-, mid-, and down-slope) and tillage treatment [i.e., conventional tillage …

Identification Of Phosphorous Loading Point Source Facilities To 303(D) Listed Nutrient Impaired Waters Through Watershed Delineation Using Arcgis For Life Cycle Assessment Applications, John Zimmerman

Chemical Engineering Undergraduate Honors Theses

The work done for this project is part of a larger “life cycle assessment (LCA) of novel electrochemical phosphorus recovery technology at the wastewater treatment plant and U.S. watershed scales” (Morrissey 2019). The goal of that LCA is to determine “environmental impacts of implementing electrochemical struvite recovery at the wastewater treatment plant, U.S watershed, and global scales” (Morrissey 2019). This project’s goal is to identify locations deemed more sensitive to eutrophication impacts. The results will be used as part of the life cycle inventory (LCI) accounting for geographically explicit phosphorus flows. The waters identified as impaired were sourced from the …

Analysis Of Titan's Fluvial Features Using Numerical Modeling, Jeshurun Horton

Mechanical Engineering Undergraduate Honors Theses

River channels have been observed near the Huygens probe landing site on the surface of Titan, along with evidence of rounded water ice boulders transported through fluid flow. Evidence near the landing site suggests active flow of liquid methane, which has motivated the study of the effects of sediment load and channel sizes on Titan’s fluvial features. A numerical model is used to determine the viscosity, flow velocity, and critical boulder transport diameter based on channel size, slope, and a range of sediment concentrations. This model achieves two ends: first, observed boulder diameters are used to determine the ideal channel …

Contrastive Learning For Unsupervised Auditory Texture Models, Christina Trexler

Computer Science and Computer Engineering Undergraduate Honors Theses

Sounds with a high level of stationarity, also known as sound textures, have perceptually relevant features which can be captured by stimulus-computable models. This makes texture-like sounds, such as those made by rain, wind, and fire, an appealing test case for understanding the underlying mechanisms of auditory recognition. Previous auditory texture models typically measured statistics from auditory filter bank representations, and the statistics they used were somewhat ad-hoc, hand-engineered through a process of trial and error. Here, we investigate whether a better auditory texture representation can be obtained via contrastive learning, taking advantage of the stationarity of auditory textures to …

Cover Crop Effects On Near-Surface Soil Aggregate Stability In The Southern Mississippi Valley Loess (Mlra 134), Chandler M. Arel

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Intensive agricultural cultivation within major land resource area (MLRA) 134, the Southern Mississippi Valley Loess, has led to soil erosion, soil compaction, and the overall destabilization of near-surface soil aggregates. The use of cover crops during the agricultural offseason has been shown to help alleviate soil compaction and provide stabilizing effects against soil erosion, which are particularly important as the silty soils of MLRA 134 have a large erosion potential. This study evaluated the effects of cover crop and no-cover crop treatment on silt-loam soils within MLRA 134. Treatments were implemented during Fall 2018 and Fall 2019 and consisted of …

Statistical Modeling, Learning And Computing For Stochastic Dynamics Of Complex Systems, Mohammadmahdi Hajiha

Graduate Theses and Dissertations

With the recent advances in sensor technology, it is much easier to collect and store streams of system operational and environmental (SOE) data. These data can be used as input to model the underlying behavior of complex engineered systems and phenomenons if appropriate algorithms with well-defined assumptions are developed. This dissertation is comprised of the research work to show the applicability of SOE data when fed into proposed tailored algorithms. The first purposes of these algorithms are to estimate and analyze the reliability of a system as elaborated in Chapter 2. This chapter provides the derivation of closed-form expressions that …

Economic Potash Fertilizer Rate Recommendations, Kimberly B. Oliver

Graduate Theses and Dissertations

This thesis is comprised of two studies that estimate profit-maximizing potassium (K) fertilizer application rates for various crops across different time periods. Estimation of profit-maximizing fertilizer-K rate (K*) for both studies considered the initial soil test level of K (STK) and yield response information, as traditional recommendations do, and added crop price and the cost of fertilizer. Profit maximum occurs where the marginal revenue from additional yield is equal to the marginal cost of applying an additional unit of fertilizer-K. The first study calculated K* for corn (Zea mays) and cotton (Gossypium hirsutum) and compared results to previous studies on …

Effects Of Localized Oxygen Production By Electrolysis On The First-Generation Glucose Sensor Response, Nandita Halder

Graduate Theses and Dissertations

Glucose sensors are very important for detecting blood glucose both in vitro and in vivo. First-generation glucose biosensors were based on the glucose oxidase (GOx) enzyme using molecular oxygen as the electron acceptor and therefore oxygen dependent. Unfortunately for in-vivo work, oxygen in the body is variable and limited. Alternative approaches to overcome the oxygen dependency came with their own limitations. The widely used and commercially available ex-vivo glucose test strip uses a mediator in place of oxygen to free it from oxygen dependency. The mediator-based technology, in most cases cannot be transferred to in vivo applications due to the …

Use Patterns And Influencing Factors Of Irrigation Best Management Practices In The Lower Mississippi River Basin, Merri E. Day

Graduate Theses and Dissertations

This study uses the 2016 Irrigation Survey from Arkansas, Louisiana, and Mississippi to document the use of irrigation best management practices (IBMPs), analyze use patterns, and use quantitative methods to determine factors that influence producers’ decisions regarding IBMPs. IBMPs included in the survey can be grouped as: field management practices (zero-grade leveling, precision-grade leveling, end blocking, warped surface, and deep tillage), water flow control practices (computerized pipe-hole selection, multiple-inlet irrigation, surge irrigation, alternate wetting and drying, cutback irrigation, flow meters, and pump timers), water recovery/storage practices (tail-water recovery system and on-farm storage reservoir), and advanced irrigation scheduling practices (soil moisture …

The Electrification Of The Kitchen: On The Energy Consumption Of Common Electric Cooking Appliances, Hozen Ricchie Rose Asok Rose

Graduate Theses and Dissertations

In developed countries, electricity has been gaining popularity as a source of energy for meal preparation. Utilizing electricity produced from renewable resources along with efficient electrical cooking appliances could result in sustainable clean cooking. The first objective of this research was to study the efficiency of common electrical cooking appliances—namely induction, resistance plate, resistance coil, infrared, and electric pot— by the water boiling test and the simmering test. The induction and electric pot were observed as the most efficient devices for the water boiling test. For simmering, which mimics many cooking processes, the electric pot and resistance coil were the …

Component Damage Source Identification For Critical Infrastructure Systems, Nathan Davis

Graduate Theses and Dissertations

Cyber-Physical Systems (CPS) are becoming increasingly prevalent for both Critical Infrastructure and the Industry 4.0 initiative. Bad values within components of the software portion of CPS, or the computer systems, have the potential to cause major damage if left unchecked, and so detection and locating of where these occur is vital. We further define features of these computer systems and create a use-based system topology. We then introduce a function to monitor system integrity and the presence of bad values as well as an algorithm to locate them. We then show an improved version, taking advantage of several system properties …

Theoretical Investigations Of The Structural, Dynamical, Electronic, Magnetic, And Thermoelectric Properties Of Corhysi (Y = Cr, Mn) Quaternary Heusler Alloys, Abdullah Hussain Hzzazi

Graduate Theses and Dissertations

Thermoelectric materials have potential properties for utilizing waste heat. The computations are used to estimate the electronic structure of CoRhYSi (Y = Cr, Mn) Quaternary Heusler alloys, as well as their elastic and magnetic characteristics. The full-potential linearized augmented plane wave is used in the calculations. The exchange-correlations are addressed using Perdew–Burke and Ernzerhof's generalized gradient approximation (GGA-PBE). With the exception of CoRhCrSi and CoRhMnSi, which are simple ferromagnets that are approximately half metallic in nature, electronic structure calculations demonstrate that these compounds have a gap in the minority states band and are obviously half-metallic ferromagnets. The magnetic moments of …

Data Analytics For Sustainable Food And Agriculture Systems, Megan Lord Reavis

Graduate Theses and Dissertations

The increasing concentration of anthropogenic greenhouse gases in the atmosphere is altering the climate, posing a serious threat to global agriculture and food security. Agriculture and food production contribute a quarter of all GHG emissions produced, so there is a critical need to limit emissions in this area while increasing food production to feed the anticipated 10 billion people by 2050. To address the needs of the future, data-driven solutions are needed to guide decision-making and provide support for actionable climate mitigation and survival strategies. Research efforts must be focused on analyzing problems on multiple scales, identifying new ways to …

Sigesn Light-Emitting Devices: From Optical To Electrical Injection, Yiyin Zhou

Graduate Theses and Dissertations

Si photonics is a fast-developing technology that impacts many applications such as data centers, 5G, Lidar, and biological/chemical sensing. One of the merits of Si photonics is to integrate electronic and photonic components on a single chip to form a complex functional system that features compact, low-cost, high-performance, and reliability. Among all building blocks, the monolithic integration of lasers on Si encountered substantial challenges. Si and Ge, conventional epitaxial material on Si, are incompetent for light emission due to the indirect bandgap. The current solution compromises the hybrid integration of III-V lasers, which requires growing on separate smaller size substrates …

Multifunctional Programmable Self-Assembled Nanoparticles In Nanomedicine, Yoshie Sakamaki

Graduate Theses and Dissertations

Developing methodologies to control the architecture of nanoparticles (NPs) at the atomic level prevents their inhomogeneity and leads to a variety of expected functions. Rationally designed nanoparticles can either be programmed or crystallized structures into pre-determined structures achieving tunable particle pore size and physiochemistry. In this dissertation, two broad classes of multifunctional nanoparticles are developed, metal-organic frameworks and DNA-NP aggregates.

Metal-organic frameworks are a novel class of highly porous crystalline materials built from organic linkers and metal cluster-based secondary building units. However, applications in bioremediation have not been developed very well especially in applications regarding drug delivery systems (DDS). The …

Investigation Of Optical And Structural Properties Of Gesn Heterostructures, Oluwatobi Gabriel Olorunsola

Graduate Theses and Dissertations

Silicon (Si)-based optoelectronics have gained traction due to its primed versatility at developing light-based technologies. Si, however, features indirect bandgap characteristics and suffers relegated optical properties compared to its III-V counterparts. III-Vs have also been hybridized to Si platforms but the resulting technologies are expensive and incompatible with standard complementary-metal-oxide-semiconductor processes. Germanium (Ge), on the other hand, have been engineered to behave like direct bandgap material through tensile strain interventions but are well short of attaining extensive wavelength coverage. To create a competitive material that evades these challenges, transitional amounts of Sn can be incorporated into Ge matrix to form …

Palmer Amaranth [Amaranthus Palmeri (S.) Wats.] Resistance To S-Metolachlor In The Mid-Southern Us And S-Metolachlor Dissipation In Soil, Koffi Badou Jeremie Kouame

Graduate Theses and Dissertations

Palmer amaranth [Amaranthus palmeri (S.) Wats.] presents both a high genetic diversity and propensity to evolve resistance to herbicides of several sites-of-action which have made it one of the worst weeds in US agriculture. In Arkansas, Palmer amaranth is resistant to herbicides of seven sites-of-action, which are 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor, acetolactate synthase inhibitors, microtubule inhibitors, protoporphyrinogen oxidase inhibitors, very long chain fatty acid inhibitors, glutamine synthetase inhibitors, and hydroxyphenylpyruvate dioxygenase inhibitors. Sustainable management requires a better understanding of its biology and that of herbicide environmental fate. This research had five objectives: 1) characterize the current status of Palmer amaranth …

How Are Agricultural Research Projects Conceiving Innovation? An Assessment Of The European Union Multi-Actor Projects, Samuel Brea Martinez-Collado

Graduate Theses and Dissertations

Horizon research programs are the European Union’s lighthouse for innovation and research concerning the agri-food chain, the management of natural resources, and the bioeconomy. Their innovation strategy approach is one that pursues the practical application of the research via the collaboration of all actors involved. Such strategy is the reflection of a Multi-Actor Approach as their procedure to enhance innovation. This paper presents the main trends and directions 101 Multi-Actor Projects (MAPs) are following on said approach towards innovation. The analysis is based on the use of well-defined “pathways” and “measures” proposed in the Guidelines for Evaluation of Innovation in …

Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston

Graduate Theses and Dissertations

Nutrient management in recirculating hydroponic systems requires the periodic replenishment of water and nutrients to the nutrient solution reservoir. Common nutrient management strategies, such as replenishing the reservoir with fresh solution and maintaining a constant solution electrical conductivity (EC), can lead to ion accumulation and nutrient imbalances since nutrients are taken up by roots and depleted from solution at different rates. To avoid nutritional disorders, commercial growers typically dump and replace the hydroponic solution periodically, which is wasteful and has an economic cost. A potential alternative is to specially formulate the nutrient replenishment solution to balance the supply of nutrients …

Grid Homology Invariants For Singular Legendrian Links, Richard Michael Shumate

Graduate Theses and Dissertations

If $\Lambda_{1}^{\ast}$ and $\Lambda_{2}^{\ast}$ are two oriented singular Legendrian links that are Legendrian isotopic, we first construct front diagram representations of $\Lambda_{1}^{\ast}$ and $\Lambda_{2}^{\ast}$ that have a natural allowable singular gird diagram associated to them. These allowable singular grid diagrams will always correspond to singular Legendrian links. The grid Legendrian invariants, $\lambda^{\pm}$, in the nonsingular grid homology theory have a natural extension to the singular grid theory, and are natural under the newly defined singular grid moves. This gives an invariant of singular Legendrian links, and in fact, a broader class of singular links.

Respiratory Compensated Robot For Liver Cancer Treatment: Design, Fabrication, And Benchtop Characterization, Mishek Jair Musa

Graduate Theses and Dissertations

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death in the world. Radiofrequency ablation (RFA) is an effective method for treating tumors less than 5 cm. However, manually placing the RFA needle at the site of the tumor is challenging due to the complicated respiratory induced motion of the liver. This paper presents the design, fabrication, and benchtop characterization of a patient mounted, respiratory compensated robotic needle insertion platform to perform percutaneous needle interventions. The robotic platform consists of a 4-DoF dual-stage cartesian platform used to control the pose of a 1-DoF needle insertion module. The active …

Engineering Fluorescently Labeled Human Fibroblast Growth Factor One Mutants And Characterizing Their Photophysics Properties Towards Designing Fret Assays, Mamello Mohale

Graduate Theses and Dissertations

Human fibroblast growth factor one (hFGF1) belongs to a family of 22 FGF members produced by fibroblast cells. Cell signaling during physiological processes of angiogenesis and wound healing occurs when hFGF1 binds to its receptor (FGFR). However, when heterogenous homeostasis is not maintained, fibroblast cells exhibit excessive proliferation which can lead to a myriad of cancers. smFRET is an ultrasensitive distant dependent (1-10 nm) technique capable of resolving such heterogeneity in structural dynamics and binding affinities (Kd). Therefore, we successfully designed and characterized fluorescently labeled hFGF1 tracers which span the visible light region of the electromagnetic spectrum for use in …