Digital Commons Network^™

Why Do We Need To Learn This? : An Investigation Of The Association Between Science Teachers' Use Of Utility Value Statements And Students' Immediate And Global Perceptions Of Science Utility, Stephen Spaulding Kafkas

Graduate Research Theses & Dissertations

Science teachers have many opportunities to influence their students' science utility value beliefs throughout the course of their instruction. However, many of them refrain from making statements regularly about the usefulness of the content they are teaching, and it is unclear how effective such statements are in influencing student beliefs. This study examined the week-to-week and global relationship between five dimensions of teachers' utility value statements (frequency, clarity, target, purpose, and temporality) and their students' utility value beliefs. The week-to-week relationship was assessed by the clarity of utility value expressed in six essays students produced. More global changes in students' …

Wireless Communication Integrated Hybrid Anc System With Impulsive Noise Cancellation Capability For Infant Incubator, Lilin Du

Graduate Research Theses & Dissertations

Preterm infants are often admitted into neonatal intensive care unit (NICU) to increase their survival rate. However, fragile infants are exposed to ambient noise from medical equipment and human activities. High intensities of noise have been involved with numerous advanced health effects in infants. There is a growing concern that a mechanism can be used to cancel noise both inside and outside the incubator. More and more researches show that communication between parents and infants from an early stage accelerates the maturation of infants and has good influence on infants' self-esteem and socialization. This causes the need for a medium …

Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan

Theses and Dissertations--Chemical and Materials Engineering

Silicon (Si) has been considered as a promising negative electrode material for lithium ion batteries (LIBs) because of its high theoretical capacity, low discharge voltage, and low cost. However, the utilization of Si electrode has been hampered by problems such as slow ionic transport, large stress/strain generation, and unstable solid electrolyte interphase (SEI). These problems severely influence the performance and cycle life of Si electrodes. In general, ionic conduction determines the rate performance of the electrode, while electron leakage through the SEI causes electrolyte decomposition and, thus, causes capacity loss. The goal of this thesis research is to design Si …

Lnvestigation Of The Critical Role Of Polymeric Binders For Silicon Negative Electrodes In Lithium-Lon Batteries, Jiagang Xu

Theses and Dissertations--Chemical and Materials Engineering

Silicon is capable of delivering a high theoretical specific capacity of 3579 mAh g^-1, which is about 10 times higher than that of the state-of-the-art graphite-based negative electrodes for lithium-ion batteries (LIBs). However, the poor cycle life of silicon electrodes, caused by the large volumetric strain during cycling, limits the commercialization of silicon electrodes. As one of the essential components, the polymeric binder is critical to the performance and durability of lithium-ion batteries as it keeps the integrity of electrodes, maintains conductive path and must be stable in the electrolyte. The guideline for binder selection of silicon electrodes …

First-Principles Studies Of Structure-Property Relationships: Enabling Design Of Functional Materials, Qunfei Zhou

Theses and Dissertations--Chemical and Materials Engineering

First-principles calculations based on quantum mechanics have been proved to be powerful for accurately regenerating experimental results, uncovering underlying myths of experimental phenomena, and accelerating the design of innovative materials. This work has been motivated by the demand to design next-generation thermionic emitting cathodes and techniques to allow for synthesis of photo-responsive polymers on complex surfaces with controlled thickness and patterns. For Os-coated tungsten thermionic dispenser cathodes, we used first-principles methods to explore the bulk and surface properties of W-Os alloys in order to explain the previously observed experimental phenomena that thermionic emission varies significantly with W-Os alloy composition. Meanwhile, …

Understanding Dna Condensation By Low Generation (G0/G1) And Zwitterionic G4 Pamam Dendrimers, Min An

Theses and Dissertations--Chemistry

Cationic polymers have shown potential as gene delivery vectors due to their ability to condense DNA and protect it from cellular and restriction nucleases. Dendrimers are hyperbranched macromolecules with precisely defined molecular weights and highly symmetric branches stemming from a central core. The nanosize, tunable surface chemistries and ease of surface functionalization has made dendrimers an attractive alternative to conventional linear polymers for DNA delivery applications. The commercially available, cationic dendrimer poly(amidoamine) or PAMAM is the most widely studied dendrimer for use as a gene delivery vector. The aim of this dissertation is to provide an increased understanding of the …

Design, Synthesis And Physicochemical Analysis Of Ruthenium(Ii) Polypyridyl Complexes For Application In Phototherapy And Nucleic Acid Sensing, Erin Melissa Wachter

Theses and Dissertations--Chemistry

Current chemotherapeutics exhibit debilitating side effects as a result of their toxicity to healthy tissues. Reducing these side effects by developing chemotherapeutics with selectivity for cancer cells is an active area of research. Phototherapy is one promising modality for selective treatment, where drug molecules are “turned on” when irradiated with light, reducing damage to healthy tissues by spatially restricting the areas exposed to irradiation. A second approach to improve selectivity is to exploit the differences in cancerous versus healthy cells, such as increased metabolism and/or upregulation of cell surface receptors. Ruthenium(II) polypyridyl complexes are candidates for phototherapy due to their …

Towards Catalytic Oxidative Depolymerization Of Lignin, Justin K. Mobley

Theses and Dissertations--Chemistry

Lignin is one of the most abundant and underutilized biopolymers on earth. Primarily composed on three monolignol units (sinapyl, coniferyl, and p-coumaryl alcohol), lignin is formed through a radical pathway resulting in an assortment of linkages, of which the β-O-4 linkage is the most prevalent (up to 60% in some hardwood species). In planta, lignin plays an important role in water transport and in protecting plants from chemical and biological attack. Traditional attempts to depolymerize lignin have focused on the cleavage of β-O-4 linkages via thermal or reductive routes. However these pathways lead to low-value, unstable product mixtures. Moreover, …

The Development Of Colorimetric Assays To Determine The Identity And Frequency Of Specific Nucleobases In Dna Oligomers, Elizabeth Marie Thomas

Theses and Dissertations--Chemistry

Colorimetric methods combined with color-changing chemical probes are widely used as simple yet effective tools for identifying and quantifying a wide variety of molecules in solution. For nucleic acids (DNA and RNA), perhaps the most commonly used colorimetric probe is potassium permanganate, which can be used to identify single-stranded pyrimidines (thymine and cytosine) in polymers. Unfortunately, permanganate is not an effective probe for identifying purines (adenine and guanine), especially in the presence of the more reactive pyrimidines. Therefore, robust methods for discriminating between the purines remain elusive, thereby creating a barrier toward developing more complex colorimetric applications. In this dissertation, …

Using Conventional And In Situ Transmission Electron Microscopy Techniques To Understand Nanoscale Crystallography, Bethany M. Hudak

Theses and Dissertations--Chemistry

Transmission electron microscopy (TEM) is a powerful tool for studying solidstate crystalline systems. With the advances in aberration correction, monochromation, and in situ capabilities, these microscopes are now more useful for addressing fundamental materials chemistry problems than ever before. This dissertation will illustrate the ways in which I have been using high-resolution imaging and in situ heating in the TEM during my Ph.D. research to investigate unique solid state chemistry questions.

This dissertation will focus on four unique crystal systems: thermoelectric skutterudite crystals, vapor-liquid-solid (VLS) grown nanowires, and hafnium dioxide nanorods. Although these systems are very different from one another, …

Analysis Of Metal Cutting Process Using Abrasive Water Jet, Saumil Patel

Graduate Research Theses & Dissertations

Abrasive water jet (AWJ) cutting is one of the most developing technologies for metal cutting process. It is superior in processing very difficult to cut material which are highly sensitive to temperature variation compared to other machining processes. Although cutting capability in terms of surface roughness, depth of jet penetration and kerf quality are the major obstructions limiting its pertinence, more study is required to understand the cutting process and cutting mechanism, and to optimize cutting performance. This research is to conduct comparative study of effecting parameters such as abrasive mass flow rate, standoff distance of nozzle from workpiece, water …

Automatic Machine Learning-Guided Methods For 3d Synapse Quantification In Confocal Neuron Images, Jonathan William Sanders

Graduate Research Theses & Dissertations

This thesis explores computational methods for automatically detecting and quantifying synapses in complex 3D neuronal images. The resulting approach is a novel combination of traditional image processing, machine learning algorithms, and multi-channel comparison methods designed to overcome the unique challenges posed by these images. The methods investigated combine the strengths of each of these components in order to produce an overall method that is capable of fully detecting the synapses in large 3D confocal neuron images with minimal interaction. Human annotation of 3D neuron images remains prohibitively difficult and subjective, and computational analysis tools are highly desirable in the expanding …

21st Century Assessment : An Examination Of The Relationship Among Computer-Adaptive Homework, Self-Regulation Strategies And Student Scores On Computer-Adaptive Assessment, Darla Bennett-Smailis

Graduate Research Theses & Dissertations

This study investigated the relationship between fifth grade students' computer-adaptive assessment performance (TAP) scores when a computer-adaptive eLearning platform was assigned for homework along with a self-regulated learning (SRL) treatment intervention. The adaptive learning theoretical model and the TAP conceptual framework supported the rationale for the utilization of the digital computer-adaptive systems of learning and assessing. In addition, the study examined the predictive ability of the Measures Strategy Learning Questionnaire (MSLQ) a self-reporting survey on MAP assessment performance scores. The theory of SRL provided the foundation for the strategies implemented in this study. The participants consisted of three fifth-grade classes …

Analysis And Extension Of A Flexible Stochastic Differential Equation Model To Estimate The Amount Of Nanoconjugates Required To Initiate Remission Of Cancer, Nicholas Joseph Skradski

Graduate Research Theses & Dissertations

This thesis examines a definition of reliability that can be applied to targeted nanoconjugate chemotherapy in cancer and also simulates a stochastic differential equation model to attempt to predict the estimated time until remission when using targeted nanoconjugate chemotherapy utilizing a recursive algorithm to attempt to find the dose of nanoconjugates that will result in remission by an expected time T. Areas of research that can be used to obtain model parameter values are cited and values for the dose of nanoconjugates, given as number of nanoconjugates, are predicted for several different model parameters. The model is then extended to …

Differences Among Subgroups In Concurrent And Predictive Validity Of Timed Oral Reading Fluency Measures And Informal Reading Inventories On Performance On Computer Adaptive Assessments Of Reading, Paul J. Perry

Graduate Research Theses & Dissertations

Recent legislation such as No Child Left Behind and the Performance Evaluation Reform Act (PERA) increasingly pressure teachers and schools to be accountable for instructional time in the form of improved test scores. As a result, students are given an increasing variety of assessments in a given school year in an attempt to measure academic growth over time. These assessments frequently occur in the form of curriculum-based measures (CBM) of oral reading fluency, informal reading inventories (IRIs), computer adaptive tests (CATs) of reading, and annual high stakes assessments of reading ability. While a review of the literature reveals a well-established …

Early Pliocene Ross Sea Paleoclimate And A New Application Of The Diatom Oxygen Isotope Proxy, Hal W. Hackett

Graduate Research Theses & Dissertations

Oxygen isotope measurements (δ¹⁸O) provide valuable insight into climate conditions. These data are advantageous as paleoclimate proxies, but records are sparse in high latitude waters, where calcareous microfossils are poorly preserved in marine sediments. Over glacial timescales, high latitude regions likely have the widest variability in terms of the δ¹⁸O values of marine waters; therefore, the paucity of data in these regions greatly hinders our ability to reconstruct global climatic and environmental change. This research is motivated to investigate Southern Ocean diatoms as a way to begin filling the gap in our knowledge. Diatoms are a cosmopolitan group of siliceous …

Economics Of Network, Gender, And Ceo Compensation, Herman Sahni

Graduate Research Theses & Dissertations

One of the most perplexing phenomenons in economics is the existence of differences in average wages between the sexes for the same job, despite far less gender dispersion in educational investments, credentials, career commitment, motivation, and training. The pay gap explanations till date are too restrictive in their approach and application, which prompts the following question: Are we missing something here? This collection of works irrefutably show that under some circumstances, social capital, which is defined as the reciprocal obligations that result from business relationships, becomes a viable candidate in explaining differential earnings between men and women. Social capital is …

Edge States In Single-Layer Graphene, Harsh Deshpande

Graduate Research Theses & Dissertations

We study, analytically, the edge states in monolayer graphene. We use the Hamiltonian based on the nearest neighbour tight binding approximation. We proceed to Taylor expand the Hamiltonian about the time-reversal invariant M point. Working with this Hamiltonian, we demonstrate the presence of dispersionless edge states for graphene ribbons with zigzag edges. Taking a purely analytical approach to the problem avails us not only a better qualitative understanding, but also gives us a finer control over the system.

Educational Videogame Design Strategies Used To Improve Motivation In Engineering Students, Thomas Abdul Rasheed

Graduate Research Theses & Dissertations

The use of traditional textbooks in engineering education is uninspiring and unrewarding for engineering students, resulting in many such students' low motivation and lack of interest in their schoolwork. In contrast, the American culture's ubiquitous factor of computer technology devices contributes to effective communication and entertainment. Today, computer videogames are owned and played by 80% of American children between the ages of 8 and 18. Plus, research studies have proven that computer videogame technology can motivate students in learning environments. The use of videogames in education is therefore a user-centered strategy because most youth today are familiar with the technology …

Effect Of Geometrical Size And Unit Cell Capacity On High Performance Lithium-Ion Battery, Dharani Thej Reddy Eswarawaka

Graduate Research Theses & Dissertations

Electric Vehicles (EV) have a promising solution to the current greenhouse gas emission problems and escalating prices of the fossil fuels. One considerable factor contributing to the drawbacks of EVs is safety of the battery. Lithium ion batteries are known for their higher energy densities and potential for higher capacities thus considered one of the most important electrochemical energy storage system. Thermal run-away is critical for EVs as they have a wide range of charge and discharge rates. So effective heat transfer and protection against high operating temperatures are crucial. This study focuses on the effect of geometrical size and …

Erosion Boundary Effects Due To Fill Fraction Variation : A Study Of Quasi 2d Tumblers Of Granular Systems, Adam N. Spitulnik

Graduate Research Theses & Dissertations

Simulations of granular flow assume a consistent flowing layer profile observed in circular tumblers that were half full. While the constant shear rate model predicts mixing kinematics adequately, the model has not been empirically tested in systems where the erosion from the solid body has velocity components along the dynamic angle of repose. This thesis explores experiments that analyze the relationship be- tween tumbler fill fraction and the kinematics of the erosion boundary transition into the flowing layer. Tumblers greater than 50% full have inertial velocity along the angle of repose; fill conditions less than 50% enter with velocity opposite …

Essays In Financial Economics, Mohammadjavad Pakdel

Graduate Research Theses & Dissertations

This dissertation consists of two self-contained essays. The first essay compares out-of-sample performance of asset allocation using forward-looking information and backward-looking information. The existing literature processes forward-looking and backward-looking information using different models and consequently different sets of assumptions. Therefore, one might wonder if superior performance of portfolios using these two sources of information should be attributed to superiority of sources of information or superiority of models underlying them. In contrast, this study uses the identical stochastic volatility model to process both forward-looking and backward-looking information. The empirical results of this study show that the investor will be significantly better …

Essays In Public Economics, Xiandeng Jiang

Graduate Research Theses & Dissertations

This dissertation contains two self-contained chapters. Although each essay examines a different question and each contributes to several distinct bodies of literatures, the essays are linked by findings and implications related to public economics. The first chapter contributes to dynamic contest theory by examining the effects of a relative performance based-prize scheme on the expected effort and the final results in best-of-N contests. The second chapter investigates the relation between a sitting governor's popularity and the incumbent's tax policy choices. Chapter 1 contributes to existing literature on contest and tournament. It examines the effects of a relative performance prize scheme …

Developing Geospatial Thinking And The Science Practices Of Investigation And Evalutation With Geographic Information Systems, Kelli Hamilton

Graduate Research Theses & Dissertations

Geospatial thinking is a subset of spatial thinking, which has been identified by the National Geography Standards as an essential skill for students to gain through geography instruction (Heffron & Downs, 2013). One tool which has been shown to help students develop their geospatial thinking skills is Geographic Information Systems (GIS) (Kim & Bednraz, 2013; Lee & Bednarz, 2009; Patterson, 2007). Much of the research conducted with GIS has been in the context of social studies classrooms. This study examined the use of GIS with seventh grade students in a science classroom. Results of this study indicate that students who …

Developing Solar Panel Simulators Using Labview For Constant Load For Varying Solar Irradiance And Temperature, Preethi Suryaa Sri Balu

Graduate Research Theses & Dissertations

Solar energy is a highly renewable energy source, causing no pollution to the external environment. In the recent years, the development and implementation of solar panels is increasing rapidly in both commercial and rural areas. Further research is being done for developing efficient solar panels. Considering the current development of solar panels, it is pivotal for the next generation of engineers to focus on research and development of solar panels. The objective of this thesis is to develop a solar panel simulator using LabVIEW software. LabVIEW software is used for its graphical programming, which makes understanding the working of solar …

Collaboration And Critical Thinking In An Online Chemistry Environment, Elizabeth Irene Kershisnik

Graduate Research Theses & Dissertations

The purpose of this dissertation was to examine collaboration and student's critical thinking and cognitive achievement within online chemistry courses. This quantitative study focused on the apparent lack of research relating collaboration and critical thinking in online science courses. Collaboration was determined using the small group collaboration model coding scheme, which examined student postings in asynchronous discussion forums for quantity, equality, and shareness. Critical thinking was measured using the chemistry concept reasoning test, the online self-diagnostic test, and also asynchronous student homework discussion postings that were coded using the community of inquiry cognitive presence indicators. Finally cognitive achievement was determined …

Computational Analysis Of Solar Pond For Energy Storage And Desalination, Vyas Raghavan

Graduate Research Theses & Dissertations

Desalination of sea water with a help of solar pond is one of the most promising and developing technology. Salinity gradient solar ponds are essentially low cost solar energy collectors with integrated energy storage system, and hence are potential, cheaper alternatives to flat plate collectors system in certain locations. Solar ponds combine solar energy collection with long-term storage and can provide reliable thermal energy. The salt water has natural tendency to form a salt gradient in a water body with higher density salt water at the bottom and low density water at the top. In a solar pond the solar …

Connecting Philosophy And Practice In The Fabric Of Public Education : An Analysis Of K-12 Instructional Technology Discourse Inspired By Foucault's Technologies Of The Self, Alan Clemens

Graduate Research Theses & Dissertations

This study was undertaken to better understand the discourse surrounding K-12 instructional technologies as represented in published articles of three trade publications whose target audience is educational practitioners. The study additionally sought to test the viability of an analytical framework inspired by Michel Foucault's technologies of the self. Two hundred and thirty-seven articles published in three trade periodicals (Education Week, Learning & Leading with Technology, and The School Administrator) over a two-year sample period were analyzed using NVIVO, a qualitative data analysis software product from QSR, International.

Constrained And Coxeter Table Algebras, Andrew P. Wang

Graduate Research Theses & Dissertations

Table algebras are algebraic structures which generalize distinct but related configurations such as the adjacency algebra of an association scheme, a group algebra (and its center), and the algebra formed by the characters of that group. In this dissertation, we study table algebras generated by involutions, which are associated with Coxeter (association) schemes, an alternate representation of regular Tits buildings. Coxeter table algebras, like Coxeter schemes, are defined by two characteristics, constrainedness and the exchange condition. The exchange condition for table algebras and schemes generalizes the exchange condition for Coxeter groups. Our first principal result shows that, for certain cases, …

The Effect Of Strain Rates On The Formability Of Commercial Pure Titanium Foils, Kechuang Zhang

Graduate Research Theses & Dissertations

Due to its hexagonal close-packed (HCP) crystal structures and limited slipping systems, commercial pure titanium shows low ductility. However, high-velocity deformation can be quite effective in increasing forming limits. In this present study, the formability of CP grade 2 titanium foils (38[micro]m) at various forming speeds were studied by experimental approach. A series of microlimited dome height ([micro]LDH) tests were conducted to examine the stamping formability of CP grade 2 titanium foils at different test speeds (0.01mm/s, 12m/s, 17m/s) on both MTS and split Hopkinson bar. Two different punch sizes (2mm, 20mm) were also used in [micro]LDH tests at quasi-static …