Physical Sciences and Mathematics Commons^™

Luminescent Group 11 Metal (I) Chalcogen Clusters With A Conjugated Diphosphine Ligand, Kai Yu Jeffrey Li

Electronic Thesis and Dissertation Repository

Polynuclear Au (I) complexes exhibit rich photochemical properties and have the potential to find applications as molecular sensors, switches, or energy storage devices. Although dinuclear Au (I) complexes with bridging diphosphines have been extensively examined, most of those reported do not contain rigid-diphosphine ligands.

This thesis examines how the rigid diphosphine, 4,6-bis(diphenylphosphino)dibenzofuran (DBFDP) can be incorporated for the controlled assembly of photoluminescent gold (I) metal – chalcogenolate (chalcogenolate = RS^-, RSe^-; R = organic moiety) and gold (I) chalcogenide (chalcogenide = S^2-, Se^2-) bimetallic complexes. In these studies, the chalcogen …

Effect Of Passivation And Surface Treatment Of A Laser Powder Bed Fusion Biomedical Titanium Alloy On Corrosion Resistance And Protein Adsorption, Saman Nikpour, Jeffrey Henderson, Sina Matin, Heng-Yong Nie, Jonas Hedberg, Vahid Dehnavi, Yara Hosein, David Holdsworth, Mark Biesinger, Yolanda Hedberg

Chemistry Publications

The biomedical titanium alloy Ti6Al4V has excellent corrosion resistance and biocompatibility and is, therefore, widely used in orthopedic and orthodontic implants. Biomedical implants are increasingly fabricated by additive manufacturing, such as laser powder bed fusion (LPBF). These manufacturing protocols often include sandblasting, surface finish, and passivation. This study aims to investigate the effect of different surface finishes and the commonly used ASTM F86-13 nitric acid passivation for LPBF Ti6Al4V on its corrosion resistance, metal release, and surface changes in benign (bovine serum albumin in a pH 7.4 buffer) and harsh (hydrochloric acid at pH 1.5) solutions using various electrochemical and …

Exploring The Reactivity Of Metal-Ligand Cooperative Complexes With Dioxazolones, Terminal Alkynes, And 2-Ethynylbenzyl Alcohol, Megan A. Hoffer Miss

Electronic Thesis and Dissertation Repository

N-Acyl ketenimines were attempted to be synthesized catalytically by [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ with phenylacetylene and 3-phenethynyl-1,2,4-dioxazol-5-one. Trapping agents were employed to identify the major product of the reaction, as many products were formed. [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ reacts with 3-phenethynyl-1,2,4-dioxazol-5-one generating an isocyanate via the Curtius rearrangement, confirmed by a forced Curtius rearrangement with 3-phenethynyl-1,2,4-dioxazol-5-one and 1,2,4-triazole. Rates of vinylidene formation using [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ and various terminal alkynes of different sterics and electronics were evaluated using a Hammett analysis for and simple rate comparisons. …

Hydrogen Bond Activation Of Donor Acceptor Cyclopropanes, Matthew H.J. Pamenter

Electronic Thesis and Dissertation Repository

Donor acceptor cyclopropanes (DACs) are versatile organic building blocks used in the synthesis of many pharmaceutically relevant heterocycles. The combination of a high ring strain cyclopropane core and vicinal donor and acceptor substituents cause DACs to behave like 1,3-zwitterions. Recently, DACs have been activated by a hydrogen bond donor solvent in place of a Lewis acid catalyst, allowing the elimination of heavy metals commonly used in these transformations. Hexafluoroisopropanol (HFIP) as a hydrogen bond donor cosolvent was found to cause a downfield shift of the DACs electrophilic carbon in the 13C NMR spectrum. This indicates increased electrophilicity at this position …

A Bio-Tribocorrosion Comparison Between Additively Manufactured And Forged Ti6al4v Parts, Sina Matin, Sahar Toorandaz, Saman Nikpour, Hamidreza Abdolvand, Eshan Toyserkani, Yolanda S. Hedberg

Chemistry Publications

Ti6Al4V has been used widely as a biomedical alloy and is increasingly manufactured by additive manufacturing due to customized shapes. As implant material, it is frequently exposed to both friction and corrosive environments. This study investigates the effect of the fabrication process (laser powder bed fusion and forging) on the tribocorrosion behavior of Ti6Al4V in various environments including diluted hydrochloric acid to simulate the acidic environment in a crevice (HCl), phosphate-buffered saline (pH 7.3) with 10 g/L bovine serum albumin (PBS+BSA), and PBS+BSA with 30 mM H2O2. While the presence of BSA hindered the repassivation (reforming of the protective passive …

Experimental And Simulation Study Of Reactive Silver Ink Droplet Evaporation, Weipeng Zhang

Electronic Thesis and Dissertation Repository

The evaporation of particle-free silver ink droplets on heated substrates directly impacts the morphology of the resultant silver particles and films. In this thesis, COMSOL Multiphysics simulations of the solvent (water-ethylene glycol mixture) droplet evaporation process are used to explain the microflows, mass transfers, and heat distribution responsible for the experimental observations. The reactive ink incorporates fluoro-surfactant FS-31 and poly (acrylamide) (PAM) to suppress the coffee-ring effect that negatively impacts the electrical conductivity. Experiments show that the droplet evaporation process results in varied silver particle morphology, depending on the locations within the droplet, leading to uneven surfaces. Large particles (3 …

Corrosion Related To The Nuclear Waste Containers, Ali Ebrahimzadeh Pilehrood

Corrosion Research

The disposal of nuclear waste is a demanding topic, and the existing methods, whether it is temporary storage in spent fuel pools or storage in geological repositories, both face the risk of corrosion-related problems. Any failure in these storage methods can potentially lead to the release of radioactive materials into the environment. To avert such catastrophic scenarios, people in the nuclear industry consistently monitor and maintain these storage facilities endlessly and attempt to improve the plans designed to store nuclear waste. Here, I will examine the nuclear waste management organization (NWMO) plan in Canada. Choosing an appropriate location for the …

Corrosion Of Implant Materials In The Human Body, Maedeh Barzmehri

Corrosion Research

This paper extensively examines the complex problem of implant corrosion occurring within the human body. The corrosion of implants gives rise to substantial challenges, encompassing compromised implant durability, patient safety concerns, and potential adverse impacts on the long-term functionality of the medical device. The study's primary objectives include offering a concise overview of the various corrosion mechanisms that impact a range of implant materials and outlining health complications linked to the byproducts of implant corrosion. Furthermore, it delves into a cost analysis specific to hip or knee revision arthroplasty, which has become a prevalent scenario in implant failure cases on …

Corrosion Case Study On Pipeline, Kangze Ren

Corrosion Research

The Kashagan pipeline leaks were likely caused by sulfur stress corrosion cracking, a combined corrosion mechanism developed by the presence of high pressure, the high level of hydrogen sulfide(the main "ingredient" of sour gas), and poor metallurgical choice. Improper welding and poor metallurgical examination were blamed for causing the leaking issue. The purpose of the current review is to raise the alarm about the inappropriate corrosion management of Kashagan oil production and its societal and environmental consequences.

On The Origins Of Life — Modelling The Initial Stages Of Complex Coacervate Droplet Formation, Yixuan Wu

Western Libraries Undergraduate Research Awards (WLURAs)

Coacervate droplets are considered a plausible model for protocells due to their spontaneous formation and ability to compartmentalize macromolecules such as nucleic acid and peptides. Although experimental studies have observed and synthesized coacervates under different laboratory conditions, little is known about their structure. Here we present atomistic molecular dynamic simulations of the interactions between water and oppositely charged proteins that cluster together in a salt-dependent process. Observing such liquid-liquid phase separation on an atomic level would serve as a model for the initial stages of complex coacervate formation. Molecular Dynamics was used to compute diagnostics of the structure at different …

The Impact Of Lead Corrosion Relating To The Contamination Of Drinking Water In Canada And In Indigenous Communities., Jessie A. Mcdonald

Corrosion Research

No abstract provided.

The Impact Of Lead Corrosion Relating To The Contamination Of Drinking Water In Canada And In Indigenous Communities., Jessie A. Mcdonald

Corrosion Research

No abstract provided.

Synergistic Effect Of Nanoclay And Barium Sulfate Fillers On The Corrosion Resistance Of Polyester Powder Coatings, Jinbao Huang, Marshall Shuai Yang, Chengqian Xian, James Joseph Noel, Yolanda S. Hedberg, Jian Chen, Ubong Eduok, Ivan Barker, Jeffrey Daniel Henderson, Haiping Zhang, Liqin Wang, Hui Zhang, Jesse Zhu

Chemistry Publications

No abstract provided.

Protein Stability In Solution And In The Gas Phase., Yousef Haidar

Electronic Thesis and Dissertation Repository

Electrospray Ionization mass spectrometry (ESI-MS) is widely used for probing proteins, yet many aspects of this technique remain elusive. Using MS, ion mobility spectrometry (IMS), and circular dichroism (CD) spectroscopy, this thesis sheds light on the stability differences of proteins in the gas phase and solution. After a general introduction (Chapter 1), Chapter 2 scrutinizes some aspects of native ESI. Our data highlight the significance of cone voltage in maintaining a native-like fold and show the advantage of using NH₄Ac in protein experiments. Chapter 3 focuses on hydrogen/deuterium exchange (HDX)-MS. Several studies have reported that D₂O …

Synchrotron Study Of Phase Transition And Heterostructures In Metal Oxide Semiconductors, Bingyu Dong

Electronic Thesis and Dissertation Repository

Transition metal oxides, including titanium dioxide (TiO₂), zinc oxide (ZnO) and Tin dioxide (SnO₂) are widely recognized semiconducting photocatalysts. This project engages in a detailed examination of the phase transition of TiO₂ and the synthesis of heterostructured metal oxides using an eco-friendly method of ball-milling. A variety of spectroscopy and microscopy techniques have been used to analyze the products. Synchrotron-based techniques: X-ray Absorption near-edge spectroscopy (XANES), X-ray Emission Spectroscopy and X-ray excited optical luminescence (XEOL) can demonstrate the local structure and bonding. The finding highlights a phase transition in TiO₂ and the formation of …

The Effect Of Hydrogen Peroxide On The Corrosion Dynamics Of Carbon Steel, Kwang Soak Gabriel O'Donnell

Electronic Thesis and Dissertation Repository

The Used Fuel Container (UFC) is a key barrier in Canada’s nuclear fuel disposal plan. Understanding the radiation-induced corrosion of the carbon steel (CS) vessel is critical for predicting the long-term integrity of the UFC. Developing a mechanistic understanding of CS corrosion and the effect of solution parameters is essential.

This work investigates the effects of H₂O₂, the key radiolytic oxidant, on CS corrosion dynamics in small, stagnant solutions. Elementary processes are identified, corrosion rates are calculated, and the effects of H₂O₂ concentration are investigated. Corrosion was studied by quantifying the concentrations of …

Application Of Crystal Engineering In Multicomponent Pharmaceutical Crystals: A Study Of Theory And Practice, Soroush Ahmadi Nasrabadi

Electronic Thesis and Dissertation Repository

Multicomponent crystallization, a prominent strategy in crystal engineering, offers the ability to modify the physicochemical properties of crystals by introducing a secondary component to their lattice structure. Such multicomponent crystals have found widespread application in the pharmaceutical industry. This thesis explores the experimental screening, characterization, application, and theoretical prediction of multicomponent crystals of Active Pharmaceutical Ingredients (APIs).

The first case study investigates a new solvate of Dasatinib which exhibits high instability at room temperature and transforms into a different polymorph upon desolvation. The crystal structure of this compound is obtained, revealing insights into its transient nature and the potential application …

Investigating Novel Luminescent Materials Towards Applications In Light Emitting Electrochemical Cells, Kenneth Chu

Electronic Thesis and Dissertation Repository

The search for new and better luminescent materials is becoming increasingly important, as there are significant cost-savings in using luminophores that are brighter and more efficient. Carbon quantum dots (CQDs) and other luminescent materials such as Pt-Ag nanoclusters and TADF compounds are an extremely appealing alternative to existing light-emitting materials, as they are low-cost, easy to synthesize, and non-toxic.

This thesis explores the properties and performance of different luminescent materials to be used in light-emitting electrochemical cells (LECs). In this work, we focused on LECs as their low cost and ease of fabrication aligns well with the ethos of CQDs …

Study On The Self-Repairing Effect Of Nanoclay In Powder Coatings For Corrosion Protection, Marshall S. Yang, Jinbao Huang, Hui Zhhang, James Noel, Yolanda S. Hedberg, Jian Chen, Ubong Eduok, Ivan Barker, Jeffrey D. Henderson, Chengqian Xian, Haiping Zhang, Jesse Zhu

Chemistry Publications

Powder coatings are a promising, solvent-free alternative to traditional liquid coatings due to the superior corrosion protection they provide. This study investigates the effects of incorporating montmorillonite-based nanoclay additives with different particle sizes into polyester/triglycidyl isocyanurate (polyester/TGIC) powder coatings. The objective is to enhance the corrosion-protective function of the coatings while addressing the limitations of commonly employed epoxy-based coating systems that exhibit inferior UV resistance. The anti-corrosive and surface qualities of the coatings were evaluated via neutral salt spray tests, electrochemical measurements, and surface analytical techniques. Results show that the nanoclay with a larger particle size of 18.38 µm (D50, …

Skin Permeation Studies Of Chromium Species - Evaluation Of A Reconstructed Human Epidermis Model., L Hagvall, M Munem, M Hoang Philipsen, M Dowlatshahi Pour, Yolanda S. Hedberg, P Malmberg

Chemistry Publications

A reconstructed human epidermis (RHE) model, the EpiDerm, was investigated and compared to human skin ex vivo regarding tissue penetration and distribution of two chromium species, relevant in both occupational and general exposure in the population. Imaging mass spectrometry was used in analysis of the sectioned tissue. The RHE model gave similar results compared to human skin ex vivo for skin penetration of Cr

The Effect Of Solution Parameters On The Interfacial Chemical Dynamics Of Early-Stage Corrosion, Brianna K. Rector

Electronic Thesis and Dissertation Repository

Corrosion is a key long-term degradation process for metallic components in nuclear industry infrastructure. Accurately predicting the corrosion rate of a component in its service environment is considered a grand challenge in the corrosion community. Corrosion is a multi-step electrochemical process, with elementary steps involving mass transfer across more than one stage. Due to the multi-step, multi-phase nature of corrosion systems, predicting corrosion behaviour over time is complex. Existing corrosion models can describe electron transfer and mass transport steps independently, under narrow sets of conditions or over a specified duration but cannot account for the changes that occur over time …

Investigating The Structure Of The Oxide On Ni-Cr-Mo Alloys While Presenting A Method For Analysis Of Complex Oxides Using Quases, Adam M. Morgan, Jeffrey D. Henderson, Brad A. Kobe, Mark Biesinger, James J. Noel

Chemistry Publications

X-ray photoelectron spectroscopy (XPS) is a technique that is widely used to studythin oxide films because of its extremely high surface sensitivity. Utilizing theQUASES (Quantitative Analysis of Surfaces by Electron Spectroscopy) software pack-age developed by Sven Tougaard (University of Southern Denmark), a user canobtain additional information that is not extracted in conventional XPS analysis, spe-cifically the composition as a function of depth. Presented here is the QUASES analy-sis of four Ni-Cr-Mo alloys performed while testing various inelastic mean free path(IMFP) determination methods in the context of providing a framework for the analy-sis of complex oxides in QUASES. Ni-Cr-Mo alloys are …

Corrosion Case Study On Automobile, Grace Ajayi, Xinran Pan, Geethu Sasikala, Marshall S. Yang

Chemistry Publications

No abstract provided.

The Synthesis And Characterization Studies Of Modified Nucleobase In Pna And Dna, Gyeongsu Park

Electronic Thesis and Dissertation Repository

Nucleic acids have been extensively studied not only for their importance in biological systems as the medium of genetic information but also for their potential uses in therapeutic, diagnostic and other biological applications. As such, modified oligonucleotides and oligonucleotide analogues have drawn the attention of researchers from various disciplines. Modification of oligonucleotides can enhance their desired characteristics and engender unique properties, such as fluorescence, giving rise to a variety of applications. Peptide nucleic acid (PNA) is an oligonucleotide mimic with a pseudo-peptide backbone based on N-(2-aminoethyl)glycine that is renowned for high target binding affinity and resistance to enzyme degradation. …

Use Of Electrochemical Techniques And Statistical Analysis To Investigate The Pitting Probability Of Copper, Sina Matin

Electronic Thesis and Dissertation Repository

The development of a safe permanent disposal plan is essential for the long-term disposal of used fuel bundles. Nuclear Waste Management Organization (NWMO) has been investigating the deep geologic disposal of nuclear waste which offers the optimum passive safety system with a negligible probability of release of radionuclides into the environment.

The proposed used fuel containers (UFC) for the permanent disposal of high-level nuclear waste in Canada is comprised of a carbon steel vessel coated with a 3 mm corrosion-resistant copper layer deposited using a combination of electrodeposition and cold spray deposition. Although copper is often considered to be thermodynamically …

Designing Polymers With Stimuli-Responsive Degradation For Biomedical Applications, Chuanfeng Li, Zhengyu Deng, Elizabeth R. Gillies

Chemistry Publications

Early biomedical applications of polymers were in areas such as joint replacements and often involved durable polymers. However, biodegradable polymers are increasingly being used to perform temporary functions such as drug delivery or supporting cells, after which they can break down and be eliminated from the body. Polymers that degrade specifically in response to stimuli offer additional opportunities to control when and where this degradation occurs, enabling enhanced functions such as site-specific drug release and the early detection of disease. In this article, we will discuss recent advancements in the design, preparation, and application of stimuli-responsive polymer degradation. In …

Investigating The Structure Of Metal-Organic Frameworks And The Behaviors Of Adsorbed Guest Molecules In Mofs Via Solid-State Nmr Spectroscopy, Yihao Shen

Electronic Thesis and Dissertation Repository

Metal-organic frameworks (MOFs) are a class of hybrid organic-inorganic microporous materials with lots of significant applications including gas capture and storage, gas separation, batteries, catalysis, ion exchange and drug delivery. MOFs based on s-block metals are important due to their many practical applications. These MOFs are also very interesting because the s-block MOFs often exhibit unpredictable behavior of coordination. In this thesis, the structures of six s-block metal (Li, Na, Cs, Mg, Ca, Sr) based MOFs involving V-shaped link, 4, 4′- sulfonyldibenzoate (SDB) are characterized by various techniques including, powder X-ray diffraction, TGA and solid-state NMR spectroscopy. ¹³C CPMAS …

Oligo [Poly(Ethylene Glycol) Fumarate] Gels With Photo-Sensitive Pendent Groups, Andrew Chung

Electronic Thesis and Dissertation Repository

Stimuli-responsive hydrogels are 3D polymeric structures that offer attractive qualities within the biomedical field due to their excellent biocompatibility and tunability to be employed in drug release, wound healing, and implants. Aliphatic polyesters are biodegradable polymers that naturally degrade by the process of simple ester hydrolysis. Oligo[poly(ethylene glycol) fumarate] (OPF) is a linear polyester containing repeating units of poly(ethylene glycol) and unsaturated fumarate. OPF naturally degrades through hydrolytic cleavage into poly(ethylene glycol) (PEG) and fumaric acid which is a naturally occurring compound found in the Kreb’s cycle. However, in some cases, it would be beneficial to activate or accelerate this …

Characterization Of Deposited Copper Oxide Films On Copper Substrates, Millicent Castillo

Electronic Thesis and Dissertation Repository

The deposition of copper oxide films on copper substrates was investigated by the electrochemical, thermal, and hydrothermal oxidation of copper. The formed oxides were characterized using various surface analytical techniques to determine the film’s morphology, composition, and thickness. The results show that by growing oxides electrochemically, a duplex layer composing of CuO and Cu₂O film was formed on the copper surface, having characteristics of being porous and possessing needle-like structures. An oxide film composed of CuO and Cu₂O, which shows minimal porosity and possess mixtures of crystalline and non-crystalline structures, is formed on the copper surface …

Atomistic Details Of Peptide Reversed-Phase Liquid Chromatography From Molecular Dynamics Simulations, Pablo M Scrosati, Lars Konermann

Chemistry Publications

Peptide separations by reversed-phase liquid chromatography (RPLC) are an integral part of bottom-up proteomics. These separations typically employ C18 columns with water/acetonitrile gradient elution in the presence of formic acid. Despite the widespread use of such workflows, the exact nature of peptide interactions with the stationary and mobile phases are poorly understood. Here we employ microsecond molecular dynamics (MD) simulations to uncover details of peptide RPLC. We examined two tryptic peptides, a hydrophobic and a hydrophilic species, in a slit pore lined with C18 chains that were grafted onto SiO₂ support. Our simulations explored peptide trapping, followed by desorption …