Chemistry Commons^™

The Effects Of Solution Ph, Temperature And Redox Environment On Corrosion And Oxide Formation On Inconel X-750, Mohsen Bahrami

Electronic Thesis and Dissertation Repository

Nickel-based superalloys have a wide range of applications in different industries due to their exceptional mechanical and corrosion-resistance properties. These alloys are widely employed in the nuclear industry. Inside a nuclear reactor, these alloys are exposed to a continuous flux of gamma-radiation. When exposed to gamma-radiation, water decomposes, resulting in the production of oxidizing and reducing species. These species have a considerable effect on the redox chemistry of the solution, which controls the overall corrosion behaviour of nickel-based superalloys.

Corrosion of metals and alloys involves several elementary steps. A comprehensive understanding of these steps and how they influence each other …

A Computational Study On A Globular Protein And An Intrinsically Disordered Protein, Cecilia Chavez Garcia

Electronic Thesis and Dissertation Repository

We present molecular dynamics (MD) simulations of two protein targets for drug design: Triosephosphate isomerase (TIM) and Methyl CpG binding protein 2 (MeCP2). First, we studied three TIM proteins: TcTIM, TbTIM and a chimeric protein (Mut1). The first two are homologous enzymes with high sequence similarity, albeit different biophysical parameters. The chimeric protein has TbTIM’s sequence and 13 single point mutations, which are sufficient to obtain TcTIM-like behaviour in reactivation experiments. We analyzed the residue interaction networks observed in the all-atom MD simulations, as well as their electrostatic interactions and the impact of simulation length on them. A conserved salt …

In Situ Study Of Geological Fluid Inclusions Using 23na Nuclear Magnetic Resonance Spectroscopy, Stephen Pilar

Electronic Thesis and Dissertation Repository

²³Na Magic Angle Spinning Solid State Nuclear Magnetic Resonance (MAS SS NMR) spectroscopy has been used to study natural geological samples of halite, fluorite, and quartz to evaluate the efficacy of NMR spectroscopy for in situ fluid inclusion analysis. NaCl calibration standards yielded a strong linear correlation (R²=0.9919) for salinity, albeit only over a ~1 ppm breadth of chemical shift. Fluid inclusions were successfully identified in all three types of minerals studied using MAS NMR. Chemical analysis with Inductively Coupled Plasma -- Mass Spectrometry (ICP-MS) was employed to quantify elemental contaminants in halite samples. Powder X-Ray Diffraction …

Metal Ligand Cooperative Complexes For Acceptorless Dehydrogenation Of Amines, Matthew D. Hoffman

Electronic Thesis and Dissertation Repository

Complexes of the type [M(Cp/Cp*)(MeCN)(P^R₂N^R′₂)]PF₆ (M = Fe, Ru) were synthesized and/or tested towards acceptorless dehydrogenation (AD) of amines. The primary amine benzylamine can undergo AD to form a mixture of products, and a selection of catalysts were employed in an attempt to control product selectivity. As a result, trends in product distribution were observed by modifying the primary and secondary coordination spheres on the catalyst. A new complex, [Fe(Cp)(MeCN)(P^Ph₂N^Ph₂)]PF₆ (3a) was synthesized and characterized and was found to be a completely selective dehydrogenation …

Effects Of Gamma-Radiation On The Evolution Of Copper Corrosion Dynamics In Deep Geological Repository Solution Environments, Lindsay J. Grandy

Electronic Thesis and Dissertation Repository

The Canadian plan for permanent disposal of used nuclear fuel involves a used fuel container (UFC), a carbon steel vessel with a copper coating to provide the corrosion protection. The corrosion conditions for the copper layer of the UFC are expected to involve small, stagnant water volumes, pH values between 6 and 9, and a continuous flux of γ-radiation emitted from the radionuclides trapped in the fuel matrix. While γ-radiation does not affect the copper metal directly, humid air and water will radiolytically decompose into redox-active and acidic species which will be produced at constant concentrations and can alter the …

The Synthesis And Application Of Polyglyoxylamides, Quinton Ea Sirianni

Electronic Thesis and Dissertation Repository

Self-immolative polymers (SIPs) are a subset of degradable polymers that can be triggered to fully depolymerize with a single stimulus event. This amplifying behaviour makes them ideal for real-world applications including sensors, recyclable plastics, and drug delivery vehicles. Polyglyoxylates (PGs) are a class of SIPs that can be synthesized in a one-pot reaction and designed to respond to different stimuli including light, heat, reduction, and oxidation. However, with the exception of poly(ethyl glyoxylate) (PEtG), the various glyoxylate monomers must be prepared and purified before polymerization, which can be difficult. Furthermore, PGs typically possess properties such as water-insolubility and low glass …

Structural Tuning And Spectroscopic Characterizations Of Polysulfide As Battery Materials, Daiqiang Liu

Electronic Thesis and Dissertation Repository

Polysulfide materials have drawn extensive attention for next-generation battery development since the current lithium-ion battery has almost reached its limit regarding energy density and safety issues. Many phosphorus and sodium sulfide materials have been used in different battery types, such as solid-state and sodium-sulfur batteries. However, there are still issues that prevent these techniques from applications. In recent years, there has been increasing attention on investigations of the structural and phase transformations of electrode and electrolyte materials under high pressure. Many studies have shown that external pressure can affect structural properties and influence electrical properties. In this study, three battery-related …

Characterization Of Extracellular Vesicles By Surface-Enhanced Raman Spectroscopy, Nina M. Culum

Electronic Thesis and Dissertation Repository

Extracellular vesicles (EVs), which are nanoscale vesicles secreted by cells into biofluids, are of research interest due to their roles in intercellular communication. EVs released from mesenchymal stromal cells (MSCs) have tremendous potential in cell-free regenerative medicine, while EVs released from diseased cells are being studied as biomarkers for minimally invasive and early disease detection. Presented in this thesis are gold nanohole arrays for the capture and sensitive detection of EVs by surface-enhanced Raman spectroscopy (SERS), a plasmonic technique capable of single molecule detection. Herein, we have characterized EVs released from MSCs and ovarian cancer cells, with a focus on …

Functional Nanoparticles: Tin Monoxide And Molybdenum Disulfide Quantum Dots On Graphene Nanosheets, Denys Vidish

Electronic Thesis and Dissertation Repository

Light harvesting can be referred to the use of an ensemble of different nanoparticles, or quantum dots, or other absorbers to optimize the ability to capture a given spectrum of electromagnetic radiation (for example the solar spectrum under specific atmospheric conditions) in a light-absorbing system. To this end, different nanoparticles play complementary functions within the system and absorb or scatter light at different wavelength intervals. Light harvesting finds applications in fields as diverse as solar cells, photosynthesis and photocatalysis. Graphene supporting a set of different semiconducting nanoparticles has often been proposed as light harvesters. To further this concept, my thesis …

Synthesis And Characterization Of Re(I) Tricarbonyl Complexes Of 1,8-Naphthalimide, Priyanka Jagadeesa Prabhu

Electronic Thesis and Dissertation Repository

1,8-Naphthalimide fluorophores with amino-substituents absorb and emit in the visible region. The photophysical properties of this class of fluorophores can be modulated by altering the degree of Intramolecular Charge Transfer (ICT) in the excited state. Thus, several metal complexes with the 1,8-naphthalimide motif have been developed as cell imaging agents. In this project, four 1,8-naphthalimide ligands were synthesized by incorporating rigid linkers. Among these, three ligands also allowed the extension of π-conjugation to the naphthalimide moiety. In addition, a ligand was also synthesized without the use of a linker. Re(I) tricarbonyl complexes of these ligands were also synthesized and their …

Synchrotron X-Ray Characterizations Of Black Phosphorus: Preparation, Doping And Applications In Energy Storage, Minsi Li

Electronic Thesis and Dissertation Repository

Black phosphorus (BP), as a two-dimensional material, has attracted interest in recent decades due to its unique properties—tunable band gap and high carrier mobility. Specifically, BP shows ultra-high theoretical capacity of 2595 mA h g^-1, resulting in high potential practical applications in lithium-ion batteries (LIBs). However, several challenges limit the development of BP in the energy storage field and LIBs: 1) The cost of the current synthesis methods of BP is too high to support extensive research studies and practical applications; 2) The electrical conductivity of BP is insufficient in LIBs; 3) The huge volume change of BP …

The Design And Characterization Of Advanced Li Metal Anodes For Next-Generation Batteries, Keegan R. Adair

Electronic Thesis and Dissertation Repository

Li metal batteries have been widely regarded as the next stage of energy storage technology, which is enabled by the low electrochemical potential (-3.04 V vs. the standard hydrogen electrode) and high specific capacity (3860 mAh g^-1) of the Li metal anode. However, the implementation of Li metal anodes has been hindered by several issues including parasitic side reactions with electrolyte, large volume fluctuations, and dendrite formation which can cause short-circuits and safety issues. This thesis will cover some novel Li anode stabilization strategies while using advanced characterization techniques to provide critical information on the working mechanisms of …

Development Of Advanced Solid-State Electrolytes And Interfaces For High-Performance Sulfide-Based All-Solid-State Lithium Batteries, Feipeng Zhao

Electronic Thesis and Dissertation Repository

All-solid-state lithium batteries (ASSLBs) have become increasingly attractive due to the demand of high-energy-density and high-safety lithium-ion batteries for electric vehicles (EVs). As the core component of ASSLBs, solid-state electrolytes (SSEs) are regarded as essential to determine the electrochemical performance of ASSLBs. The inorganic SSEs is one of the most important categories in all developed SSEs, representing the advance of superionic lithium conductors as well as the cornerstone to construct flexible polymer/inorganic composite SSEs. The sulfide-based inorganic SSE is one of the most promising SSEs that is receiving a lot of attentions, because only sulfide SSEs can show ultrahigh ionic …

Nanoorthogonal Surface Modifications Of Gold Nanoparticles And Nanoclusters Through Strain-Promoted Cycloaddition Chemistry, Praveen N. Gunawardene

Electronic Thesis and Dissertation Repository

This thesis explores the preparation of thiolated gold nanoparticles (AuNPs) and thiolated gold nanoclusters (AuNCs) capable of undergoing post-assembly surface modifications using two common “bioorthogonal” click reactions: the strain-promoted alkyne-azide cycloaddition (SPAAC) reaction (which occurs between a strained-alkyne and an azide) and the strain-promoted alkyne-nitrone cycloaddition (SPANC) reaction (which occurs between a strained-alkyne and a nitrone). Due to their rapid and modifiable reaction kinetics, high chemoselectivity, and stability of the reactive partners, these reactions were originally designed to tether functional substrates to biologically sensitive biomolecules, without altering their structure or perturb the biologically sensitive environments in which they …

The Analysis Of Ginsenosides In Ginseng Garden Soil, Karina Marie Kaberi

Electronic Thesis and Dissertation Repository

American ginseng (Panax quinquefolius L.) produces natural products called ginsenosides. The biggest challenge Ontario commercial ginseng farmers face is ginseng replant disease. To understand the function of ginseng root exudates, ginsenoside accumulation and persistence over time were investigated. Currently, no reliable ginsenoside specific extraction method, characterizing the changes in soil chemistry exists. Ginsenoside extraction protocol optimization was required to determine how ginsenoside composition changed over time. Overall, protocol optimization resulted in a 30% increase in yield of ginsenosides compared to previous extraction protocols. In the ginseng gardens, ginsenoside accumulation occurs slowly and did not reach significantly measurable amounts until the …

Copper Corrosion Dynamics Under Deep Geologic Repository Conditions, Masoumeh Naghizadeh

Electronic Thesis and Dissertation Repository

Canada’s plan for the permanent disposal of spent nuclear fuel involves a multiple-barrier system contained within a deep geologic repository (DGR). The key engineered barrier is the used fuel container (UFC), which is a copper-coated carbon steel vessel. The environments to which the copper coating will be exposed in the DGR are very different from those commonly encountered in copper corrosion studies. The copper (Cu) will be in contact with thin stagnant layers of water, and the corrosion system will be exposed to a continuous flux of γ-radiation. In the presence of γ-radiation, water and humid air decompose to redox-active …

Analysis And Differentiation Of Uniform And Localized Corrosion Of Cu, Roshan J. Daljeet

Electronic Thesis and Dissertation Repository

The current plan for disposal of used nuclear fuel in Canada involves sealing the waste in steel containers coated with 3 mm of copper and burying them in a deep geologic repository (DGR). The purpose of the copper coating is to provide corrosion resistance. To achieve long term containment, it is necessary that the copper layer corrodes slowly and predictably via active dissolution rather than passivating due to film formation. Film formation could allow pitting corrosion to occur in early phase repository conditions when groundwater ions such as Cl– , SO4 2– and HCO3 – play a dominant role in …

Cationic Boron Formazanate Complexes, Benjamin D. Katzman

Electronic Thesis and Dissertation Repository

This thesis describes the synthesis and characterization of various three- and four-coordinate cationic and dicationic boron complexes supported by formazanate ([R₁-N-N=C(Ph)-N=N-R₅]⁻ ligands. The first chapter provides a review of various three-coordinate and cationic boron complexes and related applications. Chapter two examines the effect of several variations (i.e., charge, coordination number and boron-bound substituents) on the electronic structure of cationic boron formazanate complexes. Absorption spectroscopy measurements reveal that the wavelengths, intensities, and type of the first electronic transitions in cationic boron complexes can be modulated by these structural variations. Chapter three exploits the electron deficiency …

The Development Of Fluorine-18 Imaging Agents Targeting The Ghsr, Marina D. Childs

Electronic Thesis and Dissertation Repository

Molecular imaging is an interdisciplinary field of study that allows for real-time visualization of biological processes in both healthy and disease states. Fluorine-18 positron emission tomography (PET) imaging is a highly sensitive technique where molecular probes containing fluorine-18 serve to specifically locate and visualize the expression of relevant disease biomarkers. The growth hormone secretagogue receptor 1a (GHSR) is differentially expressed in cancer and cardiac pathology, making it a biomarker of interest for imaging such diseases. This thesis discusses the development and optimization of GHSR-targeting ¹⁸F-PET imaging probes as well as proposes a new imaging agent discovery technique.

Chapter 2 …

Non-Linear Effects Of Solution Parameters And Gamma Radiation On Nickel Oxidation Dynamics, Razieh Karimihaghighi

Electronic Thesis and Dissertation Repository

Nickel is the main component in nickel-based superalloys which are known for their superior corrosion resistance and mechanical properties. These alloys are used in nuclear power plants, mainly for thin-walled heat exchanger tubing where these materials are exposed to a continuous flux of ionizing radiation. The long-term corrosion behaviour of these alloys at high temperatures and in the presence of gamma-radiation is not well understood. Moreover, the mechanism by which nickel improves the corrosion resistance of these alloys is also not known. Therefore, a mechanistic understanding of the nickel oxidation process is required to develop a predictive corrosion model for …

Galvanic Corrosion Of Carbon Steel Coupled To Copper In Used Nuclear Fuel Containers, Lindsay J. Braithwaite

Electronic Thesis and Dissertation Repository

Deep geological containment of used nuclear fuel will rely on multiple engineered and natural barriers, two of which are the copper-coated used fuel containers and the compacted bentonite clay buffer boxes in which the containers will rest. This work focused on possible galvanic interactions between the copper coating and the steel substrate of the container, which may occur at a hypothetical through-coating defect. In the presence of various amounts of chloride, bentonite, and oxygen, corrosion of the copper/carbon steel couple was studied using electrochemical tests complemented by surface characterization and 3D X-ray imaging. We investigated the effects of copper-to-steel area …

High-Pressure Studies Of Flexible Metal-Organic Frameworks And Their Performance For Co2 Adsorption Using Infrared Spectroscopy, Boqing Li

Electronic Thesis and Dissertation Repository

Metal-organic frameworks (MOFs) are crystalline porous materials comprising metal ions/clusters and organic linkers. MOFs feature very large surface area and broad tunability, which distinguish them from traditional CO₂ adsorbents. High external pressure can significantly modify the framework structures and CO₂ adsorption properties of MOFs. MIL-53(Al) and NH₂-MIL-53(Al) exhibit excellent CO₂ affinity by forming hydrogen bonds between bridging OH groups and adsorbed CO₂. We used in situ infrared spectroscopy to investigate the high-pressure performance of their framework structures and CO₂ adsorption capacities. Diamond anvil cell was employed to apply high pressures in gigapascal …

Investigating The Corrosion Behaviour Of Ni-Based Alloys In Industrially Relevant Environments, Jeffrey D. Henderson

Electronic Thesis and Dissertation Repository

Typical engineering materials may experience high corrosion rates when exposed to aggressive service conditions. Such conditions include high concentrations of aggressive anions and oxidants, high solution acidity, and/or high temperatures. Alloys with high corrosion resistance may be selected to avoid material failure caused by corrosion, for example, Ni-Cr-Mo alloys. These alloys exhibit excellent corrosion resistance due to the formation of a passive oxide film, primarily containing Cr and Mo. However, film breakdown can result in localized corrosion, e.g., crevice corrosion. Localized corrosion processes can penetrate deep into the bulk alloy, threatening its integrity. While the oxide film and localized …