Digital Commons Network^™

Greenland Subglacial Drainage Evolution Regulated By Weakly Connected Regions Of The Bed, Matthew J. Hoffman, Lauren C. Andrews, Stephen F. Price, Ginny A. Catania, Thomas A. Neumann, Martin P. Lüthi, Jason Gulley, Claudia Ryser, Robert L. Hawley, Blaine Morriss

School of Geosciences Faculty and Staff Publications

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of …

Precursor Motion To Iceberg Calving At Jakobshavn Isbræ, Greenland, Observed With Terrestrial Radar Interferometry, Surui Xie, Timothy H. Dixon, Denis Voytenko, David M. Holland, Tiantian Zheng

School of Geosciences Faculty and Staff Publications

Time-varying elevations near the calving front of Jakobshavn Isbræ, Greenland were observed with a terrestrial radar interferometer (TRI) in June 2015. An ice block with surface dimensions of 1370 m × 290 m calved on 10 June. TRI-generated time series show that ice elevation near the calving front began to increase 65 h prior to the event, and can be fit with a simple block rotation model. We hypothesize that subsurface melting at the base of the floating terminus breaks the gravity-buoyancy equilibrium, leading to slow subsidence and rotation of the block, and its eventual failure.

Decline In Methylmercury In Museum-Preserved Bivalves From San Francisco Bay, California, Allison C. Luengen, Heather M. Foslund, Ben K. Greenfield

SIUE Faculty Research, Scholarship, and Creative Activity

There are ongoing efforts to manage mercury and nutrient pollution in San Francisco Bay (California, USA), but historical data on biological responses are limited. We used bivalves preserved in formalin or ethanol from museum collections to investigate long-term trends in methylmercury (MeHg) concentrations and carbon and ni- trogen isotopic signatures. In the southern reach of the estuary, South Bay, MeHg in the Asian date mussel (Musculista senhousia) significantly declined over the study duration (1970 to 2012). Mean MeHg concentrations were highest (218 ng/g dry weight, dw) in 1975 and declined 3.8-fold (to 57 ng/g dw) by 2012. This …

Preschool Intervention Programs Addressing The School Readiness Gap For Poor-To-Low-Income Children Entering Kindergarten, Marizela Soria

Capstone Projects and Master's Theses

Over the last several decades, studies using quantitative and qualitative research methods have produced positive effects on children’s learning and behavioral development. These effects vary in size and lasting effect depending on the type of program implemented. Current public policies for child care, Head Start, and state pre-K do not ensure that most American children will attend a highly effective preschool program. In actuality, a striking amount of children attend weak programs and many others attend no program at all. These fall backs in attendance are mainly associated with children in poverty-to-low-income households, (Barnett, 2008). Data supports that early childhood …

Wild Stallion Distortion Pedal, Levi E. Sullenger

Electrical Engineering

The Wild Stallion Distortion Pedal project encompasses the research, design, implementation, PCB layout, and packaging of a distortion effect pedal for the electric guitar. This project aims to use analog circuitry in order to replicate the effect of vintage tube amplifiers to create a distortion effect. The procedure includes research, design, simulations, and prototype testing in order to produce a quality distortion effect built as a stomp pedal for the electric guitar.

Multipath And Rate Stability, Junjie Liu, Roch A. Guérin

All Computer Science and Engineering Research

Originally Published In Proc. IEEE Globecom Conference - CQRM: Communication QoS, Reliability & Modeling Symposium

Development Of A Pluto Chamber For Surface Simulations, Zachary Michael Mcmahon

Graduate Theses and Dissertations

In light of the exciting new discoveries being made by the New Horizons team, more data on Pluto is available than ever before. However, with the increase in recovered data, there is now a need for laboratory data to interpret it. Laboratory simulation of these conditions and subsequent testing of materials and samples therein is now possible and necessary to understand what has been observed. To do these simulations, a vessel that can achieve low temperatures and high vacuum is required. The scope of this work presented here was to design, build, and test a chamber that could perform these …

Stratigraphy And Depositional Environment Of The Middle Atoka Formation, Central Arkoma Basin, Western Arkansas, Yueyang Wang

Graduate Theses and Dissertations

Wire line logs are widely used in analysis of the subsurface stratigraphy of the middle Atoka Formation, Central Arkoma Basin, Western Arkansas. SP log, Gamma ray log, resistivity log and conductivity log provide valuable information to construct cross sections.

The middle Atoka formation is composed of a succession of shale and sandstone alternations with thickness reaching approximately 3000 feet in the study area. It contains several sandstone units which include Morris, Tackett, Areci, Bynum, Casey and Dunn”A” separated by shale intervals. The purpose of this study is to identify these units and predict sequence stratigraphy and depositional environment by constructing …

Temporal Co2 Variations And The Influence Of Bat Colonies In Speleogenesis: Continuous Co2 Monitoring In War Eagle Cavern, Arkansas, Ginny Sue Holcomb

Graduate Theses and Dissertations

Dissolved concentrations of CO2 in a karst aquifer are a major control on calcite dissolutional processes, as CO2 combines chemically with water to form carbonic acid. As increasing amounts of CO2 are added to the system, greater resultant water aggressivity generates greater rates of dissolution. Spatial and temporal variations in carbon flux through the system may occur over a range of time scales, and high-resolution data collection is needed to truly understand and characterize such variability. Continuous CO2 monitoring in War Eagle Cavern, Arkansas, will suggest a number of influential parameters with varying degrees of importance throughout an annual cycle. …

Role Of The Inner Shell Architecture On The Various Blinking States And Decay Dynamics Of Core-Shell And Core-Multishell Quantum Dots, Pooja Bajwa

Graduate Theses and Dissertations

Colloidal semiconductor nanocrystals (quantum dots, QDs) have received much attention in recent years due to their uniquely size-tunable properties leading to a number of promising applications. Some of their most popular applications include their use as fluorescent probes in biology, as electro-optical components and in photovoltaic devices. CdSe-based QDs are particularly important because of their ease of synthesis, high photoluminescence quantum yields (PL QYs) across the whole visible spectrum and their photostabilty. Shelling of core QDs is usually carried out to improve their optical properties, minimize outer environmental effects on their properties, and avoid toxic element exposure to the environment. …

An Analysis Of Secondary Integrated Stem Lesson Plans: Common Characteristics, Learning Expectations And The Impact From The Teacher's Definition Of I-Stem, Jacob Hayward

Graduate Theses and Dissertations

This qualitative study investigated teachers’ understanding of their definition of I-STEM (Integrated STEM education), how those understandings manifested into lessons and associated lesson artifacts, how they assessed students in such lessons, and what factors or rationales supported their ability to conduct or not conduct I-STEM lessons. A survey was sent to the members of four professional organizations representing I-STEM disciplines to solicit their participation in this project. Ten teachers ranging from grades 9-12 participated in this study. Of those who responded, six teachers identified with National Science Teachers Association (NSTA), three teachers selected International Technology and Engineering Education Association (ITEEA), …

Fabrication Of Infrared Photodetectors Utilizing Lead Selenide Nanocrystals, Justin Anthony Hill

Graduate Theses and Dissertations

Colloidal lead selenide and lead selenide / lead sulfide core/shell nanocrystals were grown using a wet chemical synthesis procedure. Absorbance and photoluminescence measurements were made to verify the quality of the produced nanocrystals. Absorbance spectra were measured at room temperature, while photoluminescence spectra were measured at 77 K. Organic ligands were exchanged for shorter ligands in order to increase the conductivity of the nanocrystals. Absorption and PL spectra for both core and core/shell nanocrystals were compared. Interdigital photodetector devices with varying channel widths were fabricated by depositing gold onto a glass substrate. Lead selenide nanocrystals were deposited onto these metallic …

Discord And Global Discord In Systems Of Coupled Quantum Dots In Driven Cavities With Dissipation, And A Method For The Calculation Of Global Discord, Willa Danielle Rawlinson

Graduate Theses and Dissertations

In the field of quantum information, which is subdivided into quantum computing and quantum cryptography, quantum correlations are essential for a performance or security boost not achievable with classical means. Various quantum correlation measures exist for evaluating a state’s potential to be a qubit (quantum bit). Entanglement, or nonseparability of quantum states, is the older, better known class of measures. However, for a mixed state, quantum entanglement is an incomplete measure of quantumness. Quantum discord, and its multibody extension global discord, encompass all quantum correlations. We study systems of coupled quantum dots using these measures.

We study the discord of …

"That's Empowering!": The Influence Of Community Activism Curriculum On Gifted Adolescents' Self-Concepts, Ashley D. Beason-Manes

Graduate Theses and Dissertations

The first of the following manuscripts addresses the experiences of a group of gifted middle school students as they engaged in community action projects that provided them opportunity to become activists in their school, neighborhood, and larger community. This study pays special attention to participants’ self-concepts as measured by the Harter Self-Perception Profile for Children (2012) and through participant interviews. The study finds evidence of students’ co-cognitive components of giftedness when themes of courage, sensitivity to human concerns, and sense of destiny are applied. Main themes from Harter’s scale are also applied, and participant interviews reveal evidence of academic and …

A Gis Approach To Modeling Groundwater Levels In The Mississippi River Valley Alluvial Aquifer, Josef Orion Lilly

Graduate Theses and Dissertations

Groundwater depletion, a subject of growing concern for a significant portion of Arkansas, may lead to future economic challenges for the Arkansas Delta region. The Mississippi River Valley Alluvial Aquifer is the uppermost aquifer and features the largest groundwater capacity in the Mississippi Embayment Aquifer System. The Mississippi River Valley Alluvial Aquifer, commonly referred to as the “alluvial aquifer”, spans 53,000〖 km〗^2 underlying portions of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Illinois, and Tennessee. As the alluvial aquifer trends southward for approximately 250 miles alongside the Mississippi River, its geographical extent ranges from 50 to 125 miles wide. There is a …

Investigation Of The Optical Properties Of Pbse/Pbx Nanocrystals For Photodetector Applications, Haley Ann Morris

Graduate Theses and Dissertations

Lead selenide and lead selenide/lead sulfide core/shell nanocrystals were investigated for use in near infrared photodetectors. A colloidal synthesis method was used for both the core and core/shell configurations. The lead sulfide shell was examined in order to mitigate oxidation of the nanoparticle surface. Absorbance and photoluminescence spectra were measured at room temperature and 77 K, respectively. Transmission electron microscopy images were also obtained to confirm crystallography and size. Bulk lead selenide was simulated in WIEN2k utilizing the linear-augmented plane wave method of solving density functional theory to better understand the electronic structure of PbSe. The crystal structure, electron density, …

How Select Groups Of Preservice Science Teachers With Inquiry Orientations View Teaching And Learning Science Through Inquiry, Peggy Diana Ward

Graduate Theses and Dissertations

Although hailed as a powerful form of instruction, in most teaching and learning contexts, inquiry-based instruction is fraught with ambiguous and conflicting definitions and descriptions. Yet little has been written about the experiences preservice science teacher have regarding their learning to teach science through inquiry. This project sought to understand how select preservice secondary science teachers enrolled in three UTeach programs in Arkansas conceptualize inquiry instruction and how they rationalize its value in a teaching and learning context. The three teacher education programs investigated in this study are adoption sites aligned with the UTeach Program in Austin, TX that distinguishes …

Bioorthogonal Reactions: Synthesis And Evaluation Of Different Ligands In Copper Catalyzed Azide-Alkyne1,3-Dipolar Cycloaddition (Cuaac), Zainab Abdullah Almansaf

Graduate Theses and Dissertations

The Copper CatalyzedAzide-Alkyne1,3-Dipolar Cycloaddition (CuAAC) reaction has unique features that qualify it to be one of the best click reactions. Its applications have been shown in different aspects and for multiple purposes. The oxidative degradation of biological systems (labile proteins and live cells) is, however, generally recognized as the major problem when using this reaction in living systems. Reactive oxidation species can be easily produced in the presence of copper(II), ascorbate and air, and this is the main cause of toxicity. However, the uses of ligands have shown a major impact on reducing copper toxicity, protecting Cu(I) from the redox …

Liming Characteristics Of A High-Calcium, Dry Flue Gas Desulfurization By-Product And Its Effects On Runoff Water Quality, Jason Richard Burgess-Conforti

Graduate Theses and Dissertations

In 2013, only 37% of the 32 million Mg of flue gas desulfurization (FGD) by-products generated in the United States were reused beneficially. If FGD by-products could be used as a beneficial soil amendment, millions of megagrams may be diverted away from surface impoundments and landfills. The purpose of this research was to identify the liming characteristics of a high-Ca dry FGD (DFGD) by-product in comparison to a Class-C fly ash (FA) and reagent-grade CaCO3, and to evaluate the effects of land application to a managed grassland on runoff, plant, and soil quality. Liming characteristics were determined by measuring the …

Direct Attachment Of 4-Hydroxybenzoic Acid Polymers And Capture Agents To Flat Sheet And Microdialysis Membranes For Improved Mass Transport, Sarah Jane Phillips

Graduate Theses and Dissertations

Microdialysis (MD) sampling is a diffusion-based separation method which has the ability to sample any analyte that can diffuse across the semi-permeable membrane. However one challenge for MD is that for soluble proteins greater than 10 kDa, the relative recovery (RR) using a 100 kDa MD probe is between 1-5%.1 There are two major barriers that lead to these low recovery values - nonspecific adsorption (NSA) and poor solute mass transport. To overcome these two barriers, the modification of PES-based MD membranes has been initiated by laccase. Previous researchers have used laccase to modify PES flat sheet and hollow fiber …

Synthesis, Characterization, And Fabrication Of All Inorganic Quantum Dot Leds, Haider Baqer Salman

Graduate Theses and Dissertations

Quantum Dot LEDs with all inorganic materials are investigated in this thesis. The research was motivated by the potential disruptive technology of core shell quantum dots in lighting and display applications. These devices consisted of three main layers: hole transport layer (HTL), electron transport layer (ETL), and emissive layer where the emission of photons occurs. The latter part was formed of CdSe / ZnS core-shell quantum dots, which were synthesized following hot injection method. The ETL and the HTL were formed of zinc oxide nanocrystals and nickel oxide, respectively. Motivated by the low cost synthesis and deposition, NiO and ZnO …

Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix

Graduate Theses and Dissertations

As is commonly known, the world is full of technological wonders, where a multitude of electronic devices and instruments continuously help push the boundaries of scientific knowledge and discovery. These new devices and instruments of science must be utilized at peak efficiency in order to benefit humanity with the most advanced scientific knowledge. In order to attain this level of efficiency, the materials which make up these electronics, or possibly more important, the fundamental characteristics of these materials, must be fully understood. The following research attempted to uncover the properties and characteristics of a selected family of materials. Herein, zinc …

Cover Crop Establishment And Potential Benefits To Arkansas Farmers, Ashley Elizabeth Humphreys

Graduate Theses and Dissertations

Soybean farmers in Arkansas need best management practices (BMPs) that maximize the benefits of using cover crops including planting date and fertilization recommendations. An evaluation of cover crop species, planting dates, seeding rates, fertilizer rates, and N accumulation aids in providing these BMPs. The first objective of this research is to assess the effect of planting date on biomass production, as well as looking at the interaction of seeding rate or fertilizer rate for legumes or non-legumes, respectively, using Austrian winter pea (Pisum sativum), cereal rye (Secale cereale), black oats (Avena strigosa), wheat (Triticum aestivum), and tillage radish (Raphanus sativus). …

Risk Assessment And Research Synthesis Methodologies In Food Safety: Two Effective Tools To Provide Scientific Evidence Into The Decision Making Process, Juan E. Ortuzar

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The food supply chain is a complex and diverse system. Some food products need minimum processing to reach the consumers, while others involve several different processes, countries and suppliers, can take several months to be on the table of the end consumer. Regarding food safety, the public health of consumers is at stake and the consequences of outbreaks could prove disastrous. This has been recognized as a matter of global importance for the food industry and authorities around the world since several efforts to improve quality, safety and trade of food have arisen since the early 1960s. The birth of …

Bikebot: A Study In Reinforcement Learning, April L. Kutz, Kristen A. Brennan, Jeremy Dixon, Nathan Bogdonas

Honors Capstones

In the United States, there is a lack of young adults interested in studying Science, Technology, Engineering, and Math (STEM). One way to help spark interest in STEM is a classroom aid that demonstrates how STEM can be fun and how it is used to push the limits of modern technology. BikeBot was designed for just this purpose. BikeBot is a robotic bicycle that utilizes an algorithm called Q-learning. Q-Learning is a type of reinforcement machine learning program, a basic form of artificial intelligence, that will allow BikeBot to balance without any explicit controls. The algorithm was tested and proven …

Exploring The Experinces Of Secondary Students In Using The Scientific Calculator As A Tool For Learning Mathematics: A Case Of A Secondary School In Rachuonyo South Sub-County, Kenya, Edith Owano Ndong'a

Master of Education

Mathematics is central in the technological development of any country. It is for this reason therefore that educational technology has been recognised as an essential component in the process of preparing students for technological and industrial advancement. Thus in the year 2002 the Kenya Ministry of Education recommended the use of scientific calculators to be used in the teaching and learning of mathematics and also during exams in secondary schools in Kenya. The intention of this move was to ensure that time was not wasted in solving mathematical problems and also improve students’ performance (Ochanda & Indoshi, 2011). However the …

Experiences Of Hearing Impaired Learners In Assessment, Jenniffer Jeptepkeny

Master of Education

This study sought to find out the experiences of HI leaners in assessment.The HI students are those whose ability to hear and subsequently engage in conversation is severely compromised by their inability to hear. As part of the governments‟ agenda to provide free education to all children the HI students have been admitted in inclusive schools. However, they face many challenges and opportunities in their quest for an education and more specifically when engaging with assessment activities. Assessment activities are crucial to learning as they give insight into the extent of which the student has learnt. This study sought to …

Exploring Community Primary Teachers’ Experiences In The Generalist Based Teaching Subject Allocations. The Case Of Two Schools In Newala Urban, Ahmad Awadh Mussa

Master of Education

The approaches to allocating subjects to primary school teachers in Tanzania have been affected with the changes in the systems of instruction between the generalist and specialist systems. While the prevailing approach to subject allocations is based in the generalist system, the presence of both specialist and generalist teachers in schools have made those teachers experience varying associated feelings, challenges, and ways to address those challenges. This study explores these experiences of teachers by first creating an understanding, strengths and weaknesses of each system before examining teachers’ views regarding the more ideal approach to subject allocations. Data was collected using …

Learners‟ Conceptual Understanding And Misconceptions Of Fractions In Primary Schools In Amuria District Local Government, Uganda, Erumu Simon Peter

Master of Education

Fractions are a core part of the mathematics curriculum, important in their own right and also as a building block to more advanced topics. There is clear evidence, however, that the teaching and learning of fractions pose a challenge to many teachers and learners in primary schools the world over, with a number of common misconceptions resulting in persistent errors in learners‟ work. If these errors are not addressed at their early stages, it becomes a challenge to address them. In this study a sample of 20 Ugandan primary 5 and 6 children were given 7 additional lessons on fractions …

The Readiness Of Rural Government Secondary Schools In Uganda To Teach Information And Communication Technology (Ict) As A Dedicated Subject On The Curriculum: A Case Study Of Two Schools In Yumbe District, Baiga Solomon

Master of Education

This study sought to establish the readiness of two rural government secondary schools in Uganda to teach Information and Communication Technology (ICT) as a dedicated subject on the curriculum as part of the effort to equip the students with the necessary skills necessary for them to be able to access the benefits of ICTs both for enhancing their education and also for enabling them to fit and work successfully in an increasingly ICT- driven world. This qualitative study involved two schools in the rural district of Yumbe, in West Nile, Northern Uganda. The findings of this study suggest that schools …