Digital Commons Network^™

Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J

Theses and Dissertations (Comprehensive)

A critical problem facing agriculture today is being able to consistently and sustainably provide plants with adequate nutrients for growth. With this problem being exacerbated by the ever-increasing human population, new perspectives and techniques are required to ensure global food security. In order to fully realize potential solutions, however, plant growth and nutrition cannot be exclusively focused upon. The soil-microorganism-plant system is comprised of many interconnected and interdependent processes that together support plant growth: it is upon these processes that the focus must be placed. In this work, the agromineral Spanish River Carbonatite (SRC) is characterized using the framework of …

Sm And Dy Interaction With Dissolved Organic Matter (Dom) In Freshwater Measured By Ion-Selective Electrode And Fluorescence Quenching Analytical Techniques, Alexandra Carvajal

Theses and Dissertations (Comprehensive)

With the increased demand for lanthanide metals in various industries, companies are looking into mining of these metals in Northern Canada. The release of these metals into the environment may have adverse effect on aquatic ecosystems; thus, it is important to understand potential toxicological effects of lanthanides on aquatic organisms. One way to predict these effects is by using a Biotic Ligand Model (BLM). Although incorporation of lanthanides into the model will require a substantial amount of future research, initial studies into speciation and toxicity can provide a useful basis for future reference. There are two main objectives to this …

Space-Time Modelling Of Emerging Infectious Diseases: Assessing Leptospirosis Risk In Sri Lanka, Cameron C F Plouffe

Theses and Dissertations (Comprehensive)

In this research, models were developed to analyze leptospirosis incidence in Sri Lanka and its relation to rainfall. Before any leptospirosis risk models were developed, rainfall data were evaluated from an agro-ecological monitoring network for producing maps of total monthly rainfall in Sri Lanka. Four spatial interpolation techniques were compared: inverse distance weighting, thin-plate splines, ordinary kriging, and Bayesian kriging. Error metrics were used to validate interpolations against independent data. Satellite data were used to assess the spatial pattern of rainfall. Results indicated that Bayesian kriging and splines performed best in low and high rainfall, respectively. Rainfall maps generated from …

Nickel And Copper Mixture Toxicity To Daphnia In Soft Water, Prachi Deshpande

Theses and Dissertations (Comprehensive)

Industrially important metals, such as Cu and Ni, sometimes are present at elevated concentrations in lakes, including those in the Sudbury, ON region. Although they are essential metals, their divalent-cation state (Cu²⁺ and Ni²⁺) can be toxic at high concentrations in the water. The free-ion toxicity of each of these metals has been studied in isolation, but rarely as a mixture. The economic importance of Cu²⁺ and Ni²⁺ makes them essential to study in the context of mixture toxicity. The objectives were to: (1) determine Cu and Ni mixture toxicity to Daphnia through acute LC50 …

Scalar Short-Term Memory, Tyler D. Bancroft

Theses and Dissertations (Comprehensive)

The location of the brain’s working and short-term memory (WM/STM) “system” is unclear. The existence of a dedicated WM/STM system is itself under debate. Recently, it has been proposed that WM/STM storage relies not on a dedicated system in prefrontal cortex, but rather that it is an emergent function of interaction between attentional and representational systems (e.g., sensory cortex) in the brain. However, mnemonic representations of very simple stimuli have repeatedly been shown to exist in frontal cortex. In this manuscript, I use computational and behavioural methods to demonstrate similarities between the representations of different types of very simple stimuli …

Do Toxicity Modifying Factors Influence Acute Or Chronic Toxicity Of Thulium To Hyalella Azteca?, Alexandria H. Loveridge

Theses and Dissertations (Comprehensive)

The industrial demand for rare earth elements (REEs) is growing and as a result, environmental exposure is a concern. Very little is understood about the toxicity of REEs in aquatic environments. The objective of this research is to evaluate the acute and chronic toxicity of Tm and to also understand the toxicity modifying influence of dissolved organic matter (DOM) and cationic competition (Ca2+, Mg2+ and Na+). Furthermore, the aim of this study was to determine linkages between Tm bioaccumulation, growth and survival during chronic exposures. Standard methods (Environment Canada) were followed for both 96h acute and 14d chronic tests, in …

Multi-Criteria Decision Analysis (Mcda) For Agricultural Sustainability Assessment, Byomkesh Talukder

Theses and Dissertations (Comprehensive)

Multi Attribute Utility Theory (MAUT), Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) and Elimination methods of Multi-Criteria Decision analysis (MCDA) are tested to assess and compare the sustainability of different agricultural systems. Indicators and composite indicators are derived from data gathered using the agricultural sustainability categories of Productivity, Stability, Efficiency, Durability, Compatibility and Equity (PSEDCE).

Agricultural systems around the world face challenges from current agricultural practices, over-exploitation of natural resources, population growth and climate change. As a result, understanding agricultural sustainability has become a global issue. Assessment is a first step in benchmarking and tracking agricultural sustainability and …

The Role Of Organic Matter In The Surface Chemistry Of Arsenic Compounds On Iron−(Oxyhydr)Oxides Studied By Atr-Ftir, Arthur Situm

Theses and Dissertations (Comprehensive)

The interaction of organic matter with the interfaces of active soil components such as iron oxides is ubiquitous within soil environments. The presence of organics at these interfaces may have implications for other soil constituents whose mobility is controlled by their ability to bind to active soil components. Most of the studies performed to date which look at these interactions are bulk/batch studies performed ex-situ. Attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was utilized within this work to study interactions between select model organics (citrate, oxalate and pyrocatechol) and iron−(oxyhydr)oxides, as well as their effect on the surface …

Epr Paradox, Nonlocality, And Entanglement In Multi-Qubit Systems, Raja Emlik

Theses and Dissertations (Comprehensive)

Bell inequalities were formulated by John Bell to test the possible violation of local realistic theories by quantum mechanical systems. It was shown that entangled quantu-m states of multiple particles violate various Bell’s inequalities. This proved that quan-tum mechanics allows correlations between spatially separated systems that have no classical analogue. The main focus of this work is to investigate genuine multiqubit non-locality in families of entangled 3 and 4-qubit pure states by studying a Bell-type inequality that is violated only if all qubits are non-locally correlated. We numerically study the relationship between entanglement and violation of the Svetlichny Bell-type inequality. …

The Kinetic Characterization Of Two Putative Galactosidases, Bt2857 And Sco6594, And The Preliminary Analyses Of Sco6595-97, Maria Ngo

Theses and Dissertations (Comprehensive)

Bacteroides thetaiotaomicron is a prolific bacterium found in the distal intestinal tract of humans that possesses the ability to breakdown complex polysaccharides through the release of carbohydrate-active enzymes (CAZymes). Overall, the saccharolytic prowess of B. thetaiotaomicron presents an intriguing model for understanding microbial-host nutrient exchange within the gut and to identify novel mechanisms for accessing carbohydrates. The successful expression, purification, and preliminary kinetic characterization of BT2857 are reported. BT2857 was found to be enzymatically active against the artificial substrate, 4-nitrophenyl β-D-galactopyranoside (pNP-Gal); suggesting its role as a putative β-galactosidase and allowed for the quantification of BT2857 activity by the determination …

Comparing The Regio- And Enantioselectivity Of Inverting Versus Retaining Epoxide Hydrolases, Mark A. Aliwalas

Theses and Dissertations (Comprehensive)

Epoxide hydrolases (EHs) are enzymes that catalyze the ring opening of an epoxide, yielding a vicinal diol. This exciting class of enzymes is often associated with natural product and small molecule biosynthesis. One interesting class of natural products that epoxide hydrolases are involved in the biosynthesis of is the enediynes. Previously, 5 enediyne-associated epoxide hydrolases have been characterized, revealing an inverting-versus-retaining paradigm for enediyne epoxide hydrolases. The work described herein sets the table for future studies involving the probing of the α/β-epoxide hydrolase mechanism for styrene oxide. Kinetic and regioselectivity characterization of the enediyne-associated CynF and SghF has determined that …

Spontaneous Helix Formation In Non-Chiral Bent-Core Liquid Crystals With Fast Linear Electro-Optic Effect, Sithara P. Sreenilayam, Yuri Panarin, Jagdish K. Vij, Vitaly P. Panov, Anne Lehmann, Marco Poppe, Marko Prehm, Carsten Tschierske Carsten Tschierske

Articles

Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies. Present display technologies are based mainly on nematic LCs, which suffer from limited response time for use in active colour sequential displays and limited image grey scale. Herein we report the first observation of a spontaneously formed helix in a polar tilted smectic LC phase (SmC phase) of achiral bent-core (BC) molecules with the axis of helix lying parallel to the layer normal and a pitch much shorter than the optical wavelength. This new phase shows fast (∼30 μs) grey-scale switching due to the deformation of …

Modeling Of Rheological Properties For Entangled Polymer Systems, Nilanjana Banerjee

Doctoral Dissertations

"The study of entangled polymer rheology both in the field of medicine and polymer processing has their major importance. Mechanical properties of biomolecules are studied in order to better understand cellular behavior. Similarly, industrial processing of polymers needs thorough understanding of rheology so as to improve process techniques. Work in this dissertation has been organized into three major sections. Firstly, numerical/analytical models are reviewed for describing rheological properties and mechanical behaviors of cytoskeleton. The cytoskeleton models are classified into categories according to the length scales of the phenomena of interest. The main principles and characteristics of each model are summarized …

Modeling Daily Electricity Load Curve Using Cubic Splines And Functional Principal Components, Abdelmonaem Salem Jornaz

Doctoral Dissertations

"Forecasting electricity load is very important to the electric utilities as well as producers of power because accurate predictions can cut down costs by avoiding power shortages or surpluses. Of specific interest is the 24-hour daily electricity load profile, which provides insight into periods of high demand and periods where the use of electricity is at a minimum. Researchers have proposed many approaches to modeling electricity prices, real-time load, and day-ahead demand, with varying success. In this dissertation three new approaches to modeling and forecasting the 24-hour daily electricity load profiles are presented. The application of the proposed methods is …

Construction Of Multi-State Potential Energy Surfaces For Spectroscopy And Dynamics, Phalgun Lolur

Doctoral Dissertations

"This dissertation is about construction and visualization of multi-state Born-Oppenheimer potential energy surfaces which are essential for studying spectroscopy and dynamics. A potential energy surface is a mathematical function that represents the energy of a system as a function of its molecular geometry. The Born-Oppenheimer approximation enables us to solve the Schrödinger equation by separating the nuclear and electronic motions. Construction of potential energy surfaces has become a basic and crucial operation for chemists in order to compute various electronic states of molecules for understanding the spectroscopy, kinetics and dynamics of molecules. These methods have been used to successfully (i) …

A Control Theoretic Approach For Security Of Cyber-Physical Systems, Haifeng Niu

Doctoral Dissertations

"In this dissertation, several novel defense methodologies for cyber-physical systems have been proposed. First, a special type of cyber-physical system, the RFID system, is considered for which a lightweight mutual authentication and ownership management protocol is proposed in order to protect the data confidentiality and integrity. Then considering the fact that the protection of the data confidentiality and integrity is insufficient to guarantee the security in cyber-physical systems, we turn to the development of a general framework for developing security schemes for cyber-physical systems wherein the cyber system states affect the physical system and vice versa. After that, we apply …

Multiphase Field Modeling Of The Formation Path Of Delta Hydrides In Zirconium, Jacob Luke Bair

Doctoral Dissertations

"Zirconium alloys are commonly used in nuclear fuel rod claddings due to their high ductility, good corrosion resistance, and low neutron absorption cross section. Among the most important weaknesses of zirconium alloys is their affinity for hydrogen, resulting in formation of hydrides in the cladding, and leading to embrittlement and mechanical failure. Despite numerous studies on hydride precipitation in zirconium alloys, the nucleation and formation path of stable δ hydrides in α zirconium matrix are not yet fully understood.

In this Ph.D. research project, two novel quantitative phase-field models were developed and utilized to advance our understanding of mechanisms of …

Mechanisms For Improving Information Quality In Smartphone Crowdsensing Systems, Francesco Restuccia

Doctoral Dissertations

"Given its potential for a large variety of real-life applications, smartphone crowdsensing has recently gained tremendous attention from the research community. Smartphone crowdsensing is a paradigm that allows ordinary citizens to participate in large-scale sensing surveys by using user-friendly applications installed in their smartphones. In this way, fine-grained sensing information is obtained from smartphone users without employing fixed and expensive infrastructure, and with negligible maintenance costs.

Existing smartphone sensing systems depend completely on the participants' willingness to submit up-to-date and accurate information regarding the events being monitored. Therefore, it becomes paramount to scalably and effectively determine, enforce, and optimize the …

Identifying Shallow Subsurface Stratigraphy And Voids Using Dispersive Characteristics Of Electromagnetic And Surface Waves, Payman Hajiani

Doctoral Dissertations

"This dissertation presents the results of three manuscripts on spectral analysis of electromagnetic and seismic surface waves to detect subsurface stratigraphy and voids. In the first manuscript, a new technique was developed by utilizing spectral analysis of surface waves to detect subsurface openings. This technique applied the concept of group delay to evaluate the effects of subsurface voids on the phase shift domain. Seismic data sets were acquired at different sites where the shape, size, and depth of the void varied. In all surveys, the time delay technique precisely identified the locations of the subsurface openings. The second manuscript presents …

Oxidative Dehydrogenation Of Light Alkanes With Carbon Dioxide, Marktus A. Atanga

Masters Theses

”Most experts studying the global ecosystem and climate suggest that rising anthropogenic CO₂ emissions have contributed to significant global climate change in the last half-century. The development of effective strategies that convert CO₂ into energy, fuels, and chemicals are greatly preferable to oceanic or geologic sequestration options because they offer the potential to create new commercially-viable products from renewable carbon feedstock. On the other hand, the selective oxidative dehydrogenation of light alkanes (C₂-C₄) to corresponding olefins, methane reforming, and methane coupling are the major challenges for producing valuable and versatile feedstocks. The oxidative dehydrogenation …

Potassium Intake, Bioavailability, Hypertension, And Glucose Control, Michael S. Stone, Lisa Martyn, Connie M. Weaver

Articles

Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+) ATPase pump. Approximately 90% of potassium consumed (60-100 mEq) is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect …

Investigating Alaskan Methane And Carbon Dioxide Fluxes Using Measurements From The Carve Tower, Anna Karion, Colm Sweeney Colm Sweeney, John B. Miller John B. Miller, Arlyn E. Andrews, Roisin Commane, Steven Dinardo, John M. Henderson, Jacob Lindaas, John C. Lin, Kristina Luus, Tim Newberger, Pieter Tans Pieter Tans, Steven C. Wofsy, Sonja Wolter, Charles E. Miller

Articles

Northern high-latitude carbon sources and sinks, including those resulting from degrading permafrost, are thought to be sensitive to the rapidly warming climate. Because the near-surface atmosphere integrates surface fluxes over large ( ∼ 500–1000 km) scales, atmospheric monitoring of carbon dioxide (CO2) and methane (CH4) mole fractions in the daytime mixed layer is a promising method for detecting change in the carbon cycle throughout boreal Alaska. Here we use CO2 and CH4 measurements from a NOAA tower 17 km north of Fairbanks, AK, established as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), to investigate regional fluxes of …

Experimental Evaluations Of Selected Sealants To Remediate Co₂ Leakage, Aaron Jeffrey Blue

Masters Theses

"Carbon Dioxide (CO₂) sequestration into porous and permeable brine-filled aquifers is seen as one of the most feasible solutions for reducing the amount of greenhouse gases released into the atmosphere from coal-fired power plants. To safely store the CO₂, it must be trapped under an impermeable rock acting as a seal. One of the concerns with CO₂ sequestration is the generation of new fractures or reopening of existing fractures caused by CO₂ injection in the sealing formation. This project evaluates the potential of sealing these fractures by injecting sealing materials into them. These sealing …

An Imu-Based Spacecraft Navigation Architecture Using A Robust Multi-Sensor Fault Detection Scheme, Samuel J. Haberberger

Masters Theses

"Redundant sensor networks of inertial measurement units (IMUs) provide inherent robustness and redundancy to a navigation solution obtained by dead reckoning the fused accelerations and angular velocities sensed by the IMU. However, IMUs have been known to experience faults risking catastrophic mission failure creating large financial setbacks and an increased risk of human safety. Different fusion methods are analyzed for a multi-sensor network using cost effective IMUs, including direct averaging and covariance intersection. Simulations of a spacecraft in low Earth orbit are used to baseline a typical expensive IMU and compare the navigation solution obtained from a network of several …

Fluid Flow Through Deformation Band, Huining Zhang

Masters Theses

"Cataclastic deformation bands, which are common in porous sandstone, have the potential to restrict fluid flow. Geological studies have shown that permeability of deformation band shear zones can be one to five orders of magnitude less than for the sandstone host rock. However, recent studies based on simplified analytical estimates have shown that fluid flow in jointed deformation bands may not be retarded since joints play an important role in conducting fluids. In this study, 2 dimensional finite element analysis (FEA) is used to simulate the total discharge flow rate through jointed deformations. Variations of single planar and conjugate jointed …

Periclinal Folding In Ozark Plateau: A Record Of Local Karst Collapse Or Regional Tectonic Forces?, Chao Liu

Masters Theses

"The Ordovician Rubidoux Formation of the Ozark Plateau, Missouri is typically identified as mechanically competent sub-horizontal beds of medium grained sandstone. North of Licking, MO, the Rubidoux Formation was deformed into a series of dome-and-basin shaped buckle folds, exposed in road cuts over a distance of ~10 km. Such folds are highly unusual within the Ozark Plateau and their origin remains controversial. Three major hypotheses have been proposed based on field observations and stereographic analysis. Given the pervasive distribution of karst collapse throughout Missouri, one hypothesis to explain these folds is that the Roubidoux Formation sagged into collapsed caverns. A …

A Novel Anthropomorphic Flow Phantom For The Quantitative Evaluation Of Prostate Dce-Mri Acquisition Techniques, Silvin Knight, Jacinta Browne, James Meaney, David Smith, Andrew Fagan

Articles

A novel anthropomorphic flow phantom device has been developed which can be used for quantitatively assessing the ability of MRI scanners to accurately measure signal / concentration time-intensity curves (CTCs) associated with dynamic contrast-enhanced (DCE) MRI. Modelling of the complex pharmacokinetics of contrast agents as they perfuse through the tumour capillary network has shown great promise for cancer diagnosis and therapy monitoring. However, clinical adoption has been hindered by methodological problems, resulting in a lack of consensus regarding the most appropriate acquisition and modelling methodology to use and a consequent wide discrepancy in published data. A heretofore overlooked source of …

Controllable Growth Of Vertically Aligned Graphene On C-Face Sic, Yu Liu, Lianlian Chen, Donovan Hilliard, Qing-Song Huang, Fang Liu, Mao Wang, Roman Böttger, René Hübner, Alpha T. N’Diaye, Elke Arenholz Elke Arenholz, Viton Heera Viton Heera, Wolfgang Skorupa Wolfgang Skorupa, Shengqiang Zhou

Articles

We investigated how to control the growth of vertically aligned graphene on C-face SiC by varying the processing conditions. It is found that, the growth rate scales with the annealing temperature and the graphene height is proportional to the annealing time. Temperature gradient and crystalline quality of the SiC substrates influence their vaporization. The partial vapor pressure is crucial as it can interfere with further vaporization. A growth mechanism is proposed in terms of physical vapor transport. The monolayer character of vertically aligned graphene is verified by Raman and X-ray absorption spectroscopy. With the processed samples, d0 magnetism is realized …

Investigation Of A Scalable Barrel Atmospheric Plasma Reactor For The Treatment Of Polymer Particles, Hisham Abourayana, Vladimir Milosavljevic, Peter Dobbyn, Patrick J. Cullen, Denis Dowling

Articles

This study reports on the performance of a scalable barrel atmospheric plasma system for the treatment of polymer particles. A novel feature of the barrel system design is the use of a biased electrode, which also acts as the roller for the glass barrel. The plasma is generated using either helium or helium / oxygen gas mixtures. The reactor was used to activate 20 g batches of silicone, polypropylene (PP), acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate (PET) particles, each with diameters in the range 3 to 5 mm. The effect of plasma treatment time and gas flow rate on …

Screening For Peripheral Arterial Disease And Carotid Artery Disease In Patients With Abdominal Aortic Aneurysm, C. Gray, Patrick J. Goodman, Paul Cullen, Stephen Badger, Kevin O'Malley, Martin K. O'Donohoe, Ciarán O. Mcdonnell

Articles

Screening for concomitant atherosclerotic disease is important in cardiovascular risk reduction. This study assessed the prevalence of carotid artery disease (CAD) and peripheral arterial disease (PAD) in patients with known abdominal aortic aneurysms (AAAs). All patients with AAA attending the vascular laboratory between the January 1, 2007, and December 31, 2009, were eligible for a carotid ultrasound and measurement of ankle brachial indices. A total of 389 (305 males) patients were identified on the AAA surveillance program with a mean (±standard deviation) age of 76 (±8) years. The mean age of the males was 75.4 (±7.8) years, and the mean …