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University of Arkansas, Fayetteville

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Articles 871 - 900 of 2433

Full-Text Articles in Physical Sciences and Mathematics

Watershed Investigative Support To The Poteau Valley Improvement Authority: Stream Water Quality To Support Huc 12 Prioritization In The Lake Wister Watershed, Oklahoma, Bradley J. Austin, Brina A. Smith, Brian E. Haggard Feb 2018

Watershed Investigative Support To The Poteau Valley Improvement Authority: Stream Water Quality To Support Huc 12 Prioritization In The Lake Wister Watershed, Oklahoma, Bradley J. Austin, Brina A. Smith, Brian E. Haggard

Technical Reports

Nonpoint source pollution associated with human land use (agriculture and urbanization) is one of the leading causes of impairment to waterways in the United States (EPA, 2000). The primary pollutants associated with agricultural and urban land use are sediment and nutrients which enter nearby streams during rain events and are then carried downstream. These sediments and nutrients may result in water quality issues in the downstream water bodies like increased algal growth or decreased water clarity (e.g. Smith et al., 1999).


Instructions To Authors For The Journal Of The Arkansas Academy Of Science, Academy Editors Jan 2018

Instructions To Authors For The Journal Of The Arkansas Academy Of Science, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Business Meeting Report (Secretary's And Treasurer's Report), Academy Editors Jan 2018

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

Journal of the Arkansas Academy of Science

No abstract provided.


Keynote Address And Meeting Program Report, Academy Editors Jan 2018

Keynote Address And Meeting Program Report, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Journal Acknowledgments And Editorial Board, Academy Editors Jan 2018

Journal Acknowledgments And Editorial Board, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Arkansas Bulletin Of Water Research - Issue 2018, Erin E. Scott, Brian E. Haggard Jan 2018

Arkansas Bulletin Of Water Research - Issue 2018, Erin E. Scott, Brian E. Haggard

Arkansas Bulletin of Water Research

The Arkansas Bulletin of Water Research is a publication of the Arkansas Water Resources Center (AWRC). This bulletin is produced in an effort to share water research relevant to Arkansas water stakeholders in an easily searchable and aesthetically engaging way. This is the second publication of the bulletin and will be published annually. The submission of a paper to this bulletin is appropriate for topics at all related to water resources, by anyone conducting water research or investigations. This includes but is not limited to university researchers, consulting firms, watershed groups, and other agencies. Prospective authors should read the “Introduction …


Academy Presidents And Institutional Members, Academy Editors Jan 2018

Academy Presidents And Institutional Members, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Journal Of The Arkansas Academy Of Science- Volume 72 2018, Academy Editors Jan 2018

Journal Of The Arkansas Academy Of Science- Volume 72 2018, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Onsager Reciprocal Relations: Microscopic (Onsager) Or Macroscopic (Sliepcevich), R. E. "Buddy" Babcock Jan 2018

Onsager Reciprocal Relations: Microscopic (Onsager) Or Macroscopic (Sliepcevich), R. E. "Buddy" Babcock

Chemical Engineering Faculty Publications and Presentations

This paper is a combination of the discussion of two nineteenth century theoretical giantsLars Onsager and C. M. Sliepcevich, their works in general, and specifically the famousreciprocal relations of Onsager with respect to irreversible thermodynamics. Emphasis isplaced on their penetrating depth and breadth of analysis so inherently necessary in theirproblem-solving endeavors. The landscape of their work will be laid out for the readerby a comparison of Onsager’s microscopic statistical mechanics derivation of the famousreciprocal relationships and a macroscopic thermodynamic derivation published by C. M.Sliepsevich that led to considerable discussion in the literature in the 1960’s. Somelabelled this discussion a controversy; …


Table Of Contents, Academy Editors Jan 2018

Table Of Contents, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Soil Organic Carbon And Mineralization Rates At The Woolsey Wet Prairie Mitigation Site In Fayetteville, Arkansas, Zachary Tipton, Lisa S. Wood, Mary Savin, Benjamin R. Runkle Jan 2018

Soil Organic Carbon And Mineralization Rates At The Woolsey Wet Prairie Mitigation Site In Fayetteville, Arkansas, Zachary Tipton, Lisa S. Wood, Mary Savin, Benjamin R. Runkle

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Atmospheric carbon dioxide (CO2) levels are rapidly increasing, surpassing 400 ppm in 2013 from a pre-industrial revolution level of around 280 ppm. Researchers have been looking at methods to reduce CO2 levels in the atmosphere, including promoting carbon sequestration in soils. Carbon sequestration is the process where CO2 is naturally or artificially transferred out of the atmosphere and stored in the ocean, plant biomass, soils, and geologic formations. Seemingly contradictory to the notion of carbon sequestration is the use of fire as a management treatment for the restoration of native prairie grass ecosystems. Fire combusts plant …


Wave Profile For Current Bearing Lightning Strokes, Baylee Landers, M Hemmati, Ali Alzhrani Jan 2018

Wave Profile For Current Bearing Lightning Strokes, Baylee Landers, M Hemmati, Ali Alzhrani

Journal of the Arkansas Academy of Science

The propagation of breakdown waves in a gas, which is primarily driven by electron gas pressure, is described by a one-dimensional, steady-state, three-component (electrons, ions, and neutral particles) fluid model. This study will involve waves propagating in the opposite direction of the electric field force on electrons (anti-force waves—lightning return stroke) only. We consider the electron gas partial pressure to be much larger than that of the other species and the waves to have a shock front. Our set of equations consists of the equations of conservation of the flux of mass, momentum, and energy coupled with the Poisson’s equation. …


Tree Ring Dating Of The Ficklin-Imboden Log Structures, Powhatan Historic State Park, Arkansas, Kaylee R. Mcadoo, David W. Stahle Jan 2018

Tree Ring Dating Of The Ficklin-Imboden Log Structures, Powhatan Historic State Park, Arkansas, Kaylee R. Mcadoo, David W. Stahle

Journal of the Arkansas Academy of Science

Powhatan Historic State Park in Powhatan, Arkansas preserves and interprets five historical structures from 19th century Arkansas, including the Ficklin-Imboden Log House. This structure, which is actually two separate log buildings with uncertain construction dates and functions, is believed to be the earliest surviving structure at Powhatan State Park and is on the National Register of Historic Places. Powhatan State Park contracted with the University of Arkansas Tree-Ring Laboratory to develop a more accurate dating and interpretation of the log structures.

Dendrochronology (tree-ring dating) was used to determine the true felling dates of logs in both buildings. Core specimens …


Generation Of Generalized-Gauss Laser Beams Via A Spatial Light Modulator, Jessica P. Conry Young, Samantha Dix Jan 2018

Generation Of Generalized-Gauss Laser Beams Via A Spatial Light Modulator, Jessica P. Conry Young, Samantha Dix

Journal of the Arkansas Academy of Science

Generalized-Gauss laser beams can be described as a continuous transition between the well-known Hermite-Gauss (HG) and Laguerre-Gauss (LG) laser beams. A spatial light modulator (SLM) was made by removing the liquid crystal display (LCD) from an overhead projector. The homemade SLM, encoded with a computer-generated hologram, was then used to convert a fundamental Gaussian beam from a small frame Helium-Neon (HeNe) laser into several different orders of Generalized-Gauss (GG) beams. The experimentally generated GG beam profiles matched the theoretically expected profiles.


Optimum Magnetometer Transect Spacing To Locate Legacy Oil And Gas Wells: Preliminary Results, Jason A. Patton, Michael G. Davis, Kenyon J. Gowing, Hunter B. Vickers Jan 2018

Optimum Magnetometer Transect Spacing To Locate Legacy Oil And Gas Wells: Preliminary Results, Jason A. Patton, Michael G. Davis, Kenyon J. Gowing, Hunter B. Vickers

Journal of the Arkansas Academy of Science

The purpose of this project was to examine the optimum transect spacing to locate legacy oil and gas wells using an Overhauser magnetometer. Widely known to be a potential environmental hazard, legacy oil and gas wells may act as a conduit for methane and/or deeper subsurface fluids (naturally occurring brines, injected waste fluids, or injected CO2) to the surface or shallow subsurface. Many plugged wells have all surface equipment removed leaving no visible trace at the surface and thus making the environmental assessment of these wells difficult. Using a magnetometer along a set of predefined transects, magnetic anomalies …


Travel To Extraterrestrial Bodies Over Time: Some Exploratory Analyses Of Mission Data, Venkat Kodali, Rohith Kumar Reddy Duggirala, Richard S. Segall, Hyacinthe Aboudja, Daniel Berleant Jan 2018

Travel To Extraterrestrial Bodies Over Time: Some Exploratory Analyses Of Mission Data, Venkat Kodali, Rohith Kumar Reddy Duggirala, Richard S. Segall, Hyacinthe Aboudja, Daniel Berleant

Journal of the Arkansas Academy of Science

This paper discusses data pertaining to space missions to astronomical bodies beyond earth. The analyses provide summarizing facts and graphs obtained by mining data about (1) missions launched by all countries that go to the moon and planets, and (2) Earth satellites obtained from a Union of Concerned Scientists (UCS) dataset and lists of publically available satellite data.


Deep Learning-Based Framework For Autism Functional Mri Image Classification, Xin Yang, Saman Sarraf, Ning Zhang Jan 2018

Deep Learning-Based Framework For Autism Functional Mri Image Classification, Xin Yang, Saman Sarraf, Ning Zhang

Journal of the Arkansas Academy of Science

The purpose of this paper is to introduce deep learning-based framework LeNet-5 architecture and implement the experiments for functional MRI image classification of Autism spectrum disorder. We implement our experiments under the NVIDIA deep learning GPU Training Systems (DIGITS). By using the Convolutional Neural Network (CNN) LeNet-5 architecture, we successfully classified functional MRI image of Autism spectrum disorder from normal controls. The results show that we obtained satisfactory results for both sensitivity and specificity.


Comparison Of Various Mean Field Formulations For Retrieving Refractive Indices Of Aerosol Particles Containing Inclusions, Kristin S. Dooley, Jessica Deyoung Jan 2018

Comparison Of Various Mean Field Formulations For Retrieving Refractive Indices Of Aerosol Particles Containing Inclusions, Kristin S. Dooley, Jessica Deyoung

Journal of the Arkansas Academy of Science

Application of effective medium approximation (EMA) methods to two-component systems are presented. Systems studied are composed of water, sulfate, soot, and dust as these are commonly encountered atmospheric aerosol components. Atmospheric models often employ EMAs to include internally mixed aerosols without the computational burden of exact theory. In the current work, several types of mixing rules (Maxwell-Garnet, Bruggeman, and coherent potential approximation) have been applied to various two-component internally mixed particles at 550 nm using volume fractions of the minor component below 0.1. As expected, results show that the formulations tested produce very similar effective refractive indices indicating that electric …


The Potential For Phosphorus Release From Floodplain Soils: Temporal Variability And Management Strategies, Megan Amanda Reavis Dec 2017

The Potential For Phosphorus Release From Floodplain Soils: Temporal Variability And Management Strategies, Megan Amanda Reavis

Graduate Theses and Dissertations

Soils may contain large amounts of legacy phosphorus (P) due to past application of excess fertilizers, releasing P during runoff and flood events. As the level of P in soils increases, the release of P from the soils increases, but the temporal fluctuations of this release are not well known. Experiments were conducted to examine 1) the variability of soluble reactive P (SRP) release from the soil throughout a year and 2) the effect of repeated flooding and drying cycles on release rates. Soil cores were collected 7 times throughout a year from 2 sites within the Watershed Research and …


A Geochemical Investigation And Comparison Between Organic-Rich Black Shales And Mississippi Valley-Type Pb-Zn Ores In The Southern Ozarks Region, Bryan Michael Bottoms Dec 2017

A Geochemical Investigation And Comparison Between Organic-Rich Black Shales And Mississippi Valley-Type Pb-Zn Ores In The Southern Ozarks Region, Bryan Michael Bottoms

Graduate Theses and Dissertations

Mississippi Valley-type (MVT) deposits are base metal sulfide deposits that are important economic sources of both Pb and Zn, accounting for 24% of the global Pb and Zn reserves. They are found all over the world, often hosted in platform carbonates on the flanks of sedimentary basins, and often in proximity to hydrocarbons. They are epigenetic, not related to igneous activity, and thought to be sourced from low temperature, highly saline basinal brines that are expelled from sedimentary basins during compaction and/or in conjunction with an orogenic event. The basinal lithologies responsible for providing the metals for the ores are …


A Risk-Based Method For Estimating The Carbon Sequestration Budget For A Mixed Hardwood Forest, Erin Cooper Dec 2017

A Risk-Based Method For Estimating The Carbon Sequestration Budget For A Mixed Hardwood Forest, Erin Cooper

Chemical Engineering Undergraduate Honors Theses

Carbon Dioxide (CO2) levels in the atmosphere have risen from approximately 310 ppm in the 1950’s to over 400 ppm as of 2015. This rise in CO2 has likely resulted in the observed warming trend of the earth’s atmosphere in the same time frame, causing significant concern in the scientific community. Several mitigation strategies have arisen to combat the upward trend of CO2 emissions in recent decades, among them being carbon sequestration- the process of capturing CO2 from the atmosphere and holding it for an extended period of time. This study used the U.S. Forest …


Development And Characterization Of Rice Genotypes For Water Use Efficiency And Drought Resistance, Anuj Kumar Dec 2017

Development And Characterization Of Rice Genotypes For Water Use Efficiency And Drought Resistance, Anuj Kumar

Graduate Theses and Dissertations

Rice, the second largest staple food crop, uses 30% of global fresh water to complete its life cycle worldwide. Water deficits worldwide have become a serious problem affecting rice growth and ultimately grain yield. To solve the water problem globally, improvement of water use efficiency (WUE) and other drought resistance (DR) traits in rice genotypes would be a useful strategy using advanced genomics tools. In this study, our objectives were to 1) analyze phenotypes of the USDA rice mini-core collection (URMC) for WUE and DR related traits, 2) correlate drought response phenes for physiological traits and grain yield in the …


A Comparative Life Cycle Assessment Of Nutritionally Equivalent Meals With And Without Pork, Kelli Young Dec 2017

A Comparative Life Cycle Assessment Of Nutritionally Equivalent Meals With And Without Pork, Kelli Young

Graduate Theses and Dissertations

The following report details a life cycle assessment of several dietary and meal scenarios with and without pork. The goal of the LCA was to identify the impacts of greenhouse gas emissions, water use, and land use of pork containing and porkless diets and meal plans in a field-to-fork analysis. The dietary and meal plan scenarios are iso-caloric meaning they contain the same number of calories. The first set of diets is based on a USDA consumption pattern, 2000 kcal per day. This diet was used to create three other dietary scenarios with and without pork. The USDA recommended food …


The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond Dec 2017

The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond

Graduate Theses and Dissertations

Urea-N fertilizer is typically applied at the 5-leaf stage to rice (Oryza sativa L.) grown in a dry-seeded, delayed-flood production system. How long the preflood-N can be delayed without adverse effects on yield potential is poorly understood. The research objective was to determine the effects of preflood-N application and flood establishment timing on aboveground-N content, 50% heading, yield components, and grain yield. Trials were established on silt loam soils at the Pine Tree Research Station (PTRS) and Rice Research and Extension Center (RREC) during 2015 and 2016. Urea-N was applied at 0, 45, 90, 135, and 180 kg N ha-1 …


Detection Of Survival And Proliferation Of Sulfate Reducers Under Simulated Martian Atmospheric And Soil Conditions, Sergio Mosquera Mora Dec 2017

Detection Of Survival And Proliferation Of Sulfate Reducers Under Simulated Martian Atmospheric And Soil Conditions, Sergio Mosquera Mora

Graduate Theses and Dissertations

Numerous studies have tried to determine the survivability and proliferation of microorganisms under simulated Martian conditions. Furthermore, most of them have been focused on the ability of these microbes to cope with high brines’ salt (NaCl) concentrations inherent of the Martian surface. However, there are not studies related to the ability of bacteria to survive on subsurface environments that have increasing concentrations of sulfate compounds. For this research, a group of microorganisms known as sulfate-reducing bacteria or simply sulfate reducers were chosen due to their ability to use sulfate compounds as terminal electron acceptors to produce metabolic energy, their tolerance …


Exploring Energy, Comfort, And Building Health Impacts Of Deep Setback And Normal Occupancy Smart Thermostat Implementation, Zachary Ethan Alderman Dec 2017

Exploring Energy, Comfort, And Building Health Impacts Of Deep Setback And Normal Occupancy Smart Thermostat Implementation, Zachary Ethan Alderman

Graduate Theses and Dissertations

As smart thermostat adoption rates continue to increase, it becomes worthwhile to explore what unanticipated outcomes may result in their use. Specific attention was paid to smart thermostat impacts to deep setback and normal occupancy states in a variety of conditions while complying with the ventilation and temperature requirements of ASHRAE 90.2-2013. Custom weather models and occupancy schedules were generated to efficiently explore a combination of weather conditions, building constructions, and occupancy states. The custom modeling approach was combined with previous experimental data within the Openstudio graphics interface to the EnergyPlus building modeling engine. Results indicate smart thermostats add the …


Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen Dec 2017

Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen

Graduate Theses and Dissertations

Global importance of forests is difficult to overestimate, given their role in oxygen production, ecological roles in nutrient cycling and supporting numerous living species, and economic value for industry and as recreational zones. Fitness of the forest-forming trees strongly depends on microbial communities associated with tree roots. In particular, fungi impact tree fitness: mycorrhizal species provide water and nutrients for the trees in exchange for C, endophytic fungi play key roles in host defense against pathogenic organisms, and saprotrophic fungi decompose dead organic matter and facilitate nutrient cycling. In addition, pathogenic fungal species strongly affect forest fitness. Despite their importance, …


Free-Space Measurements Of Dielectrics And Three-Dimensional Periodic Metamaterials, Clifford E. Kintner Dec 2017

Free-Space Measurements Of Dielectrics And Three-Dimensional Periodic Metamaterials, Clifford E. Kintner

Graduate Theses and Dissertations

This thesis presents the free-space measurements of a periodic metamaterial structure. The metamaterial unit cell consists of two dielectric sheets intersecting at 90 degrees. The dielectric is a polyetherimide-based material 0.001” thick. Each sheet has a copper capacitively-loaded loop (CLL) structure on the front and a cut-wire structure on the back. Foam material is used to support the unit cells. The unit cell repeats 40 times in the x-direction, 58 times in the y-direction and 5 times in the z-direction. The sample measures 12” × 12” × 1” in total. We use a free-space broadband system comprised of a pair …


Seeing Prehistory Through New Lenses: Using Geophysical And Statistical Analysis To Identify Fresh Perspectives Of A 15th Century Mandan Occupation, Amber Marie Mitchum Dec 2017

Seeing Prehistory Through New Lenses: Using Geophysical And Statistical Analysis To Identify Fresh Perspectives Of A 15th Century Mandan Occupation, Amber Marie Mitchum

Graduate Theses and Dissertations

Great Plains prehistoric research has evolved over the course of a century, with many sites like Huff Village (32MO11) in North Dakota recently coming back to the forefront of discussion through new technological applications. Through a majority of its studies and excavations, Huff Village appeared to endure as the final stage in the Middle Missouri tradition. Long thought to reflect only systematically placed long-rectangular structure types of its Middle Missouri predecessors, recent magnetic gradiometry and topographic mapping data revealed circular structure types that deviated from long-held traditions, highlighting new associations with Coalescent groups. A compact system for food capacity was …


Structural And Elastic Properties Of Degenerate Sno Monolayers At Finite Temperature, Afsana Sharmin Dec 2017

Structural And Elastic Properties Of Degenerate Sno Monolayers At Finite Temperature, Afsana Sharmin

Graduate Theses and Dissertations

Chalcogen-based layered superconductors with a litharge structure such as FeS and FeSe mono-layers undergo structural and superconducting phase transitions that are tunable by doping. Representing another material platform with a litharge structure but without valence d-electrons, SnO monolayers also display a structural ground state with a degenerate rectangular unit cell at zero temperature and a charge-tunable energy barrier that leads to a thermally-controllable structural phase change. Doped SnO monolayers with rectangular degenerate unit cells give rise to two-dimensional multiferroicity. Their two-dimensional elastic energy landscape adopts a basic analytic expression that is employed to discuss this structural transition. The results contained …