Digital Commons Network^™

Anti Wetting Additives For Aluminosilicate Refractories In Molten Aluminum Contact Applications, Devdutt Pramod Shukla

Doctoral Dissertations

"Aluminosilicate based refractories are widely used in furnace installations for melting aluminum because they are inexpensive, readily available and generally exhibit the properties desired from a refractory material. However, they face severe corrosion and degradation issues due to the extremely reducing nature of molten aluminum alloys. Isothermal static cup testing is widely used as a tool to evaluate the performance of refractories against penetration by molten aluminum alloys. Various testing methods were reviewed and an upgraded static cup test was recommended. Commercially available aluminosilicate refractories were tested using this method and their results were studied in order to understand the …

Models For On-Line Social Networks, Noor Hadi

Theses and Dissertations (Comprehensive)

On-line social networks such as Facebook or Myspace are of increasing interest to computer scientists, mathematicians, and social scientists alike. In such real-world networks, nodes represent people and edges represent friendships between them. Mathematical models have been proposed for a variety of complex real-world networks such as the web graph, but relatively few models exist for on-line social networks.

We present two new models for on-line social networks: a deterministic model we call Iterated Local Transitivity (ILT), and a random ILT model. We study various properties in the deterministic ILT model such as average degree, average distance, and diameter. We …

Inuit Qaujimajatuqangit And Adaptive Co-Management: A Case Study Of Narwhal Co-Management In Arctic Bay, Nunavut, Aaron T. Dale

Theses and Dissertations (Comprehensive)

Since 2001 the community of Arctic Bay, located on north-western Baffin Island, in Nunavut, Canada, has been experimenting with a new approach to narwhal management—‘community-based’ narwhal managemet. The new management system has developed some decision-making powers to the local Hunters’ and Trappers’ Organization, who are empowered/required to draft by-laws to govern the hunt. Community-based narwhal management links local, regional, territorial, and national actors and agencies in a co-management arrangement that draws its powers from, and is steered by, the Nunavut Final Agreement (1993), the comprehensive land claims agreement between the Inuit of Nunavut and Her Majesty the Queen in Right …

Laboratory Studies In Chemically Mediated Phosphorus Removal, Rebecca L. Gilmore

Theses and Dissertations (Comprehensive)

Chemically mediated phosphorus removal, done during wastewater treatment, is an effective means of reducing nutrient loads to sensitive environments. Although this method of treatment is widely used, the mechanism of removal is poorly understood. Moreover, phosphorus regulations for wastewater effluents are moving to concentration ranges of 10-100 μg P/L (total phosphorus). This is much lower than current regulations (∼0.1 ∼0.2 mg P/L as TP) required by municipalities (Takács et al., 2006a; Murthy et al., 2005). The analytical methods for low level phosphate analysis need to be optimized to perform reliably and accurately at these low levels. To accomplish this, absorbance …

Consciousness From A Naturalistic Perspective, Hugh R. Alcock

Theses and Dissertations (Comprehensive)

Despite advances in neuroscience some sceptics, e.g., David Chalmers, Colin McGinn and Thomas Nagel, contend that we are no nearer to achieving a scientific understanding of phenomenal consciousness. These sceptics claim that naturalising consciousness, i.e., subsuming it under our scientific theories, is either impossible, at least without radically reforming our current scientific practices, or perhaps beyond our cognitive grasp. Their scepticism is based on what is called the ‘problem of consciousness’ or the ‘hard problem’. I argue that their pessimism is unwarranted. Their conclusion is based on adopting a nonnaturalistic attitude, according to which our scientific theories must accommodate our …

Computer Integration In Elementary And Secondary Schools: Variables Influencing Educators, Julie Mueller

Theses and Dissertations (Comprehensive)

Given the prevalence of computers in education today, it is critical to understand teachers’ perspectives regarding computer integration in their classrooms. Research identifying stages of implementation, and literature identifying barriers and supports, fall short of explaining what variables impact an educator’s ultimate decision to integrate technology in their instruction. The current research surveyed a heterogeneous sample of 185 elementary and 204 secondary teachers in order to provide a comprehensive summary of teacher characteristics and variables that discriminate teachers who integrate technology from those who do not. Discriminant Function Analysis (DFA) identified the following variables as making unique contributions to discriminating …

The Role Of Geospatial Thinking And Geographic Skills In Effective Problem Solving With Gis: K-16 Education, Niem Tu Huynh

Theses and Dissertations (Comprehensive)

Effective use of a Geographic Information System (GIS) is hampered by the limited geospatial reasoning abilities of students. The ability to reason with spatial relations, more specifically apply geospatial concepts, including the identification of spatial patterns and spatial associations, is important to geographic problem solving in a GIS context. This dissertation examines the broad influence of three factors on GIS problem solving: 1) affection towards computers, geography, and mathematics, 2) geospatial thinking, as well as 3) geographic skills.

The research was conducted with 104 students in Waterloo, Ontario, Canada. Students were drawn from four educational levels: grade 9 students, 13 …

The Use Of A Lock-In Amplifier To Stabilize The Frequency Of A Laser Diode, Jose M. Juarez

College Honors Program

We have designed, constructed, and tested a lock-in amplifier with readily available electronic components and homebuilt analog circuits. Its performance is comparable to that of a commercial unit, but it costs significantly less and is much more compact. The various components of our lock-in amplifier are discussed and the basic principles behind the function and operation of this versatile device are explained. We have also assembled a laser system and used the output signal of our lock-in amplifier in a negative feedback loop to stabilize the frequency of our laser to an atomic reference frequency.

Risk Of Dementia Associated With Elevated Plasma Homocysteine In A Latin American Population, Inara J. Chacon, Aldrín E. Molero, Gloria Pino-Ramírez, José A. Luchsinger, Joseph H. Lee, Gladys E. Maestre

School of Medicine Publications

The relationship between total homocysteine (tHcy) and dementia risk remains controversial, as the association varies among populations and dementia subtypes. We studied a Venezuelan population that has high prevalence of both elevated tHcy and dementia. We tested the hypotheses that (1) elevated tHcy is associated with increased dementia risk, (2) the risk is greater for vascular dementia (VaD) than for Alzheimer’s disease (AD), and (3) a history of stroke may partly explain this association. 2100 participants (≥55 years old) of the Maracaibo Aging Study underwent standardized neurological, neuropsychiatric, and cardiovascular assessments. Elevated tHcy was significantly associated with dementia, primarily VaD. …

Environmental Geochemistry Of Metal Contaminated Sediments From The Big River System Of Southeastern Missouri, Helen Carrie Bender

Masters Theses

"Geochemical analysis of stream sediments from the Big River Watershed of southeastern Missouri indicates that they contain elevated concentrations of contaminant metals such as Pb. Zn, Cu. Co, Ni and Cd. The elevated concentrations are derived from natural exposures of metal enriched strata and the numerous mine tailings piles and water seeps created as a result of about 300 years of lead-zinc mining in the “Old Lead Belt”. Galena (PbS), sphalerite (ZnS), and pyrite (FeS₂) are the primary sulfides found in the tailings piles and Scanning Electron Microscopy analysis of individual metallic sediment particles collected at intervals downstream …

Sediment Flushing In Mystic Cave, West Virginia, Usa, In Response To The 1985 Potomac Valley Flood, James J. Van Gundy, William B. White

International Journal of Speleology

The great November 5, 1985 Potomac Valley flood was responsible for the release of 1800 m³ of alluvial and colluvial sediment from the walls of the entrance doline of Mystic Cave. Flood waters were sufficiently powerful to flush the entire mass of sediment not only into the cave but through the cave. Remnants of the sediment mass in the form of sand bars and a few cobbles wedged in speleothems were the only evidence in the cave that the huge mass of sediment had moved through. The sediment moved as a suspended mass in water moving at peak velocities …

Ultraviolet Radiation Sensitivity In Cave Bacteria: Evidence Of Adaptation To The Subsurface?, Jessica R. Snider, Caitlin Goin, Robert V. Miller, Penelope J. Boston, Diana E. Northup

International Journal of Speleology

We hypothesize that a reduced capacity to withstand or repair cellular damage from ultraviolet radiation may be present in cave-adapted microorganisms that never experience such conditions. However, a small number of previous studies have shown that some subsurface bacteria do not show greater sensitivity to ultraviolet radiation (UVR) than surface bacteria. To estimate UVR sensitivity in cave bacteria, bacterial isolates were collected from Carlsbad Cavern, New Mexico, U.S.A., and percent survival following exposure to various UVC and UVA radiation doses was determined. Cave bacteria from Left Hand Tunnel in Carlsbad Cavern and surface bacteria from soil and rocks above Carlsbad …

Cryogenic Cave Carbonates From The Cold Wind Cave, Nízke Tatry Mountains, Slovakia: Extending The Age Range Of Cryogenic Cave Carbonate Formation To The Saalian, Karel Žák, Helena Hercman, Monika Orvošová, Ivana Jačková

International Journal of Speleology

Cold Wind Cave, located at elevations ranging between 1,600 and 1,700 m a. s. l. in the main range of the Nízke Tatry Mountains (Slovakia), is linked in origin with the adjacent Dead Bats Cave. Together, these caves form a major cave system located within a narrow tectonic slice of Triassic sediments. Both caves have undergone complex multiphase development. A system of sub-horizontal cave levels characterized by large, tunnel-like corridors was formed during the Tertiary, when elevation differences surrounding the cave were less pronounced than today. The central part of the Nízke Tatry Mountains, together with the cave systems, was …

Pidoplitchkoviella Terricola – An Interesting Fungus From The Domica Cave (Slovakia), Alena Nováková

International Journal of Speleology

The microfungus Pidoplitchkoviella terricola – until now it was known only as Kirilenko´s specimen isolated from Quercus robur rhizosphere in Ukraine - was found in earthworm casts in the Domica Cave, NP Slovak Karst, Slovakia. A description and microphotographs of this strain are provided in this article.

Microscopic Fungi Isolated From The Domica Cave System (Slovak Karst National Park, Slovakia). A Review, Alena Nováková

International Journal of Speleology

A broad spectrum, total of 195 microfungal taxa, were isolated from various cave substrates (cave air, cave sediments, bat droppings and/or guano, earthworm casts, isopods and diplopods faeces, mammalian dung, cadavers, vermiculations, insect bodies, plant material, etc.) from the cave system of the Domica Cave (Slovak Karst National Park, Slovakia) using dilution, direct and gravity settling culture plate methods and several isolation media. Penicillium glandicola, Trichoderma polysporum, Oidiodendron cerealis, Mucor spp., Talaromyces flavus and species of the genus Doratomyces were isolated frequently during our study. Estimated microfungal species diversity was compared with literature records from the same …

Modeling Of Vias And Via Arrays In High Speed Printed Circuit Boards, Arun Reddy Chada

Masters Theses

"This thesis presents modeling approaches for fast calculation of signals in dense via arrays in high speed printed circuit boards (PCBs) and model to hardware correlation study of solid and perforated disk resonators. A 2D finite difference (FD) method to extract the via capacitance which includes the via pad capacitance obtained by solving the laplace equation in the via domain in multi-layer geometries is presented and validated with analytical formulation for via capacitance. Next, closed-form expression for the impedance of an infinitely large parallel plane pair is derived and validated by comparing with cavity model for several numerical examples. The …

Nona-Arginine Peptides Facilitate Cellular Entry Of Semiconductor Nanocrystals: Mechanisms Of Uptake, Yi Xu

Masters Theses

"Luminescent semiconductor quantum dots (QDs) have recently been used for delivering and monitoring biomolecules, such as drugs and proteins. However, QDs alone have a very low efficiency of transport across the plasma membrane. In order to increase the efficiency of QD delivery, synthetic nona-arginine (sR9) was used, a cell penetrating peptide, to facilitate uptake. Data demonstrated that sR9 could significantly increase the cellular uptake of QDs by noncovalent binding between QDs and sR9. Furthermore, the mechanisms of QD/sR9 cellular internalization were investigated. Low temperature and metabolic inhibitors markedly inhibited the uptake of QD/sR9, indicating that internalization is an energy-dependent process. …

Electricity Generation And Ethanol Production Using Iron-Reducing, Haloalkaliphilic Bacteria, Varun Paul

Masters Theses

"Microbial life in extreme environments has been studied primarily for their metabolic activities. Very few commercial or industrial applications have been known from these systems. In this study, the metabolic pathways and properties of bacteria from a haloalkaliphilic environment of Soap Lake, Washington were employed in two research applications related to energy production. In the first study, the bacterial cultures that were known to reduce iron (III) were used in a Microbial Fuel Cell (MFC) reactor. Iron reducing bacteria have shown to shunt their electrons on to the surface of a carbon electrode of an MFC, and the electrons can …

Development Of A One Dimensional Subsurface Contaminant Transport Model With Stochastic Applications, Benjamin Waldon Johnson

Masters Theses

"Contaminant source release history is a necessary element of contaminant mass transport simulation in the saturated zone. The source release history is unknown at many sites, and many inverse models have been developed to define finite release histories. To define a likely domain of three source history parameters, a mass balancebased one dimensional approach is developed and tested by discretizing the spatial domain into bands. By incorporating the approach in a spreadsheet model, observed data is represented by both variable length and constant length bands of analysis. Each representation of observed data was tested to determine the most appropriate band …

Exploring The Use Of A Commercial Game Engine For The Development Of Educational Software, Hussain Alafaireet

Masters Theses

"Three-dimensional visualization and simulation environments are becoming increasingly important in both industrial and educational environments. However, developing these simulations can be a difficult and expensive task. Herein we explore the use of a commercial game engine to develop a 3-D, interactive computer game designed to teach players about the anatomy of a frog. The goal of this project is threefold: 1) to develop high-fidelity virtual reality educational software with a limited budget and limited personnel, 2) to define a software development process by which similar simulations can be developed, and 3) to explore the benefits that these simulations provide to …

Reliability-Based Design With System Reliability And Design Improvement, Gagandeep Singh Saini

Masters Theses

"This thesis focuses on developing a methodology for accurately estimating series system probability of failure. Existing methods for series system based design optimization are not that accurate because they assign reliability to each failure mode; as a result complete system reliability goes down. According to method proposed in this work, the user will assign required system reliability at the start and then optimizer will apportion reliability to every failure mode in order to meet required system reliability level. Detlevson second order upper bounds are used to estimate system probability of failure. Several examples have been shown to verify the results …

Fault Detection And Prediction With Application To Rotating Machinery, Gary R. Halligan

Masters Theses

"In this thesis, the detection and prediction of faults in rotating machinery is undertaken and presented in two papers. In the first paper, Principal Component Analysis (PCA), a well known data-driven dimension reduction technique, is applied to data for normal operation and four fault conditions from a one-half horsepower centrifugal water pump. Fault isolation in this scheme is done by observing the location of the data points in the Principal Component domain, and the time to failure (TTF) is calculated by applying statistical regression on the resulting PC scores. The application of the proposed scheme demonstrated that PCA was able …

Pricing Options By Simulation Using Realized Volatility, David E. Allen, Michael Mcaleer, Marcel Scharth

Research outputs pre 2011

A growing literature advocates the use of high-frequency data for the purpose of volatility estimation. However, despite the successes in modeling the conditional mean of realized volatility empirical evaluations of this class of models outside the realm of short run forecasting is limited. How can realized volatility be used for pricing options? What are the modeling qualities introduced by realized volatility models for pricing derivatives? In this short paper, we propose an options pricing framework based on a new realized volatility model that captures all the relevant empirical regularities of the realized volatility series of the S&P 500 index. We …

Evolving The Quality Of A Model-Based Test Suite, Usman Farooq, Chiou P. Lam

Research outputs pre 2011

Redundant test cases in newly generated test suites often remain undetected until execution and waste scarce project resources. In model-based testing, the testing process starts early on in the developmental phases and enables early fault detection. The redundancy in the test suites generated from models can be detected earlier as well and removed prior to its execution. The article presents a novel model-based test suite optimization technique involving UML activity diagrams by formulating the test suite optimization problem as an Equality Knapsack Problem. The aim here is the development of a test suite optimization framework that could optimize the model-based …

A Max-Min Multiobjective Technique To Optimize Model Based Test Suite, Usman Farooq, Chiou P. Lam

Research outputs pre 2011

Generally, quality software production seeks timely delivery with higher productivity at lower cost. Redundancy in a test suite raises the execution cost and wastes scarce project resources. In model-based testing, the testing process starts with earlier software developmental phases and enables fault detection in earlier phases. The redundancy in the test suites generated from models can be detected earlier as well and removed prior to its execution. The paper presents a novel max-min multiobjective technique incorporated into a test suite optimization framework to find a better trade-off between the intrinsically conflicting goals. For illustration two objectives i.e. coverage and size …

Review Of Educational And Other Approaches To Hearing Loss Among Indigenous People, Samantha Burrow, Ann Galloway, Natalie Weissofner

Research outputs pre 2011

This review article summarizes the available literature regarding educational and other approaches to hearing loss among Indigenous preschool and school children of Australia (i.e. both Aboriginal and Torres Strait Islander people). Particular attention is given to the: impact of hearing loss; factors contributing to hearing loss; prevention and management of otitis media and hearing loss; education strategies addressing hearing loss; and policies and policy implications for reducing hearing loss and its educational consequences.

Adiabatically Induced Coherent Josephson Oscillations Of Ultracold Atoms In An Asymmetric Two-Dimensional Magnetic Lattice, Ahmed Abdelrahman, Peter Hannaford, Kamal Alameh

Research outputs pre 2011

We propose a new method to create an asymmetric two-dimensional magnetic lattice which exhibits magnetic band gap structure similar to semiconductor devices. The quantum device is assumed to host bound states of collective excitations formed in a magnetically trapped quantum degenerate gas of ultracold atoms such as a Bose-Einstein condensate (BEC) or a degenerate Fermi gas. A theoretical framework is established to describe possible realization of the exciton-Mott to discharging Josephson states oscillations in which the adiabatically controlled oscillations induce ac and dc Josephson atomic currents where this effect can be used to transfer n Josephson qubits across the asymmetric …

Ballistics Image Processing And Analysis For Firearm Identification, Dongguang Li

Research outputs pre 2011

Firearm identification is an intensive and time-consuming process that requires physical interpretation of forensic ballistics evidence. Especially as the level of violent crime involving firearms escalates, the number of firearms to be identified accumulates dramatically. The demand for an automatic firearm identification system arises. This chapter proposes a new, analytic system for automatic firearm identification based on the cartridge and projectile specimens. Not only do we present an approach for capturing and storing the surface image of the spent projectiles at high resolution using line-scan imaging technique for the projectiles database, but we also present a novel and effective FFT-based …

Scada Security - Slowly Circling A Disaster Area, Craig Valli, Andrew Woodward

Research outputs pre 2011

SCADA (Supervisory Control And Data Acquisition) networks control much of the industrialised nations production and supply complexes. Various government reports and investigations have highlighted the vulnerability of these systems. Many of these systems are on private networks which are increasingly being connected to systems that are accessible from other networks such as the Internet. SCADA systems have unique security and operational requirements. However, many of the most basic security measures are missing in these networks. This examines some of these issues and proposes some technologies that could help secure these networks from attack.

Scada Forensics With Snort Ids, Craig Valli

Research outputs pre 2011

This paper is a research in progress paper outlining an approach using open source IDS (Snort) and honeypot (nepenthes, honeyd) technologies to create a resilient layered defensive approach for SCADA and control systems networks.