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Full-Text Articles in Engineering

Micromechanics Of Plasticity Of Zr-2.5%Nb Alloy, Md Imran Khan Nov 2019

Micromechanics Of Plasticity Of Zr-2.5%Nb Alloy, Md Imran Khan

Electronic Thesis and Dissertation Repository

Zirconium alloys are used in many thermal neutron fission reactors because of their very low neutron interaction cross-sections along with their excellent mechanical strength and corrosion resistance. Numerous experiments have been conducted on these alloys at the bulk scale to determine their mechanical properties. Recent advancements in micro-mechanical testing make it easier to study site-specific mechanical properties for micron or submicron-sized samples. Understanding the mechanical response of such small volumes of material is extremely important for developing accurate models to predict the ductile fracture toughness of these in-reactor materials. Pressure tubes made of Zr-2.5%Nb alloys are an integral ...


Effect Of Ion Implantation On The Mechanical Properties Of The Grain And Grain Boundary Regions Of Inconel X750, Maisaa Nezar Tawfeeq Oct 2019

Effect Of Ion Implantation On The Mechanical Properties Of The Grain And Grain Boundary Regions Of Inconel X750, Maisaa Nezar Tawfeeq

Electronic Thesis and Dissertation Repository

Annulus gas spacers in CANada Deuterium Uranium (CANDU) nuclear reactors are made from the heat-treated Inconel X750 Nickel-based alloy. This alloy is designed to have high strength and creep resistance at elevated temperature. Unlike other reactor designs, the CANDU reactor has a high thermal neutron fluence, which results in an enhancement of the radiation damage and the internal production of helium and hydrogen. They are thus susceptible to microstructural instability and mechanical property degradation with time. Studies of ex-service spacers have indicated that they display intergranular embrittlement and lower ultimate tensile strength compared to nonirradiated Inconel X750. The primary degradation ...


Design Of Cell-Instructive Biomaterial Scaffolds For Intervertebral Disc Regeneration, Nadia Sharma Sep 2019

Design Of Cell-Instructive Biomaterial Scaffolds For Intervertebral Disc Regeneration, Nadia Sharma

Electronic Thesis and Dissertation Repository

Biomaterials-based therapies targeting the nucleus pulposus (NP) have the potential to promote regeneration and restore mechanical function to the intervertebral disc. This study developed composite hydrogels incorporating decellularized NP (DNP) and assessed its effects on viability, retention and differentiation of U-CH1 cells, an NP progenitor-like cell line. A minimal protocol was developed to decellularize bovine NP that reduced nuclear content while preserving key extracellular matrix components predicted to be favourable for bioactivity. The resulting DNP demonstrated cell-instructive effects, supporting U-CH1 viability and retention within the hydrogels, and promoted the differentiation of the progenitor-like cells towards an NP-like phenotype. These studies ...


Shape-Controlled Nanoparticles As Effective Catalysts For Proton Exchange Membrane (Pem) Fuel Cells, Ali Feizabadi Sep 2019

Shape-Controlled Nanoparticles As Effective Catalysts For Proton Exchange Membrane (Pem) Fuel Cells, Ali Feizabadi

Electronic Thesis and Dissertation Repository

Polymer electrolyte membrane fuel cell (PEMFC), is considered a promising candidate for the next generation power sources in transportation, stationary and portable applications. However, oxygen reduction reaction (ORR), one of the key reactions occurring on PEMFC is kinetically slow; this has limited performance and further advancement in this kind of fuel cells. Thus, improving the PEMFC efficiency requires a thorough understanding of the ORR mechanism on the desired catalyst. To address the above-mentioned demands, the scope of this thesis is focused on the fundamental understanding of facet-controlled nanoparticles, metal-support interactions, and bimetallic platinum catalysts, utilizing synchrotron-based X-ray absorption, X-ray photoelectron ...


Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li Jun 2019

Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li

Electronic Thesis and Dissertation Repository

As a typical type of soft electroactive materials, dielectric elastomers (DEs) are capable of producing large voltage-induced deformation, which makes them desirable materials for a variety of applications in transduction technology, including tunable oscillators, resonators, biomimetics and energy harvesters. The dynamic and energy harvesting performance of such DE-based devices is strongly affected not only by multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, but also by their material viscoelasticity. Moreover, as suggested by experiments and theoretical studies, DEs possess nonlinear relaxation processes, which makes modeling of the performance of DE-based devices more challenging.

In this thesis ...


Fabrication And Characterization Of Collagen-Polypyrrole Constructs Using Direct-Ink Write Additive Manufacturing, Rooshan Arshad May 2019

Fabrication And Characterization Of Collagen-Polypyrrole Constructs Using Direct-Ink Write Additive Manufacturing, Rooshan Arshad

Electronic Thesis and Dissertation Repository

Current efforts in the tissue engineering field are being directed towards the creation of platforms which will facilitate in instructing cells towards biologically relevant outcomes such as stem cell differentiation and disease pathophysiology. Traditional fabrication methods serve as a limiting factor for the production of such platforms as they lack feature and geometric complexity. Additive Manufacturing (AM) offers advantage over said methods by affording designers creative freedom and great control over printed constructs. Such constructs can then be used to create appropriate models for study- ing a plethora of tissues and structures. An AM methodology for Direct-Ink Write (DIW) printing ...


Strategies For The Stabilization Of Metal Anodes For Li And Na Metal Batteries, Yang Zhao Dec 2018

Strategies For The Stabilization Of Metal Anodes For Li And Na Metal Batteries, Yang Zhao

Electronic Thesis and Dissertation Repository

Li-metal batteries (LMBs) and Na-metal batteries (NMBs) are considered as the promising candidates to replace the conventional Li-ion batteries (LIBs) due to their high theoretical energy density. For LMBs and NMBs, Li metal and Na metal are the ultimate choices to achieve their high energy density due to the high specific capacity, low electrochemical potential and lightweight. However, as alkali metals, both Li and Na metal anodes suffer from serious challenges including 1) Li/Na dendrite formations and short circuits; 2) Low Coulombic efficiency (CE) and poor cycling performance; and 3) Infinite volume changes. This thesis mainly focuses on the ...


Corrosion Dynamics Of Carbon Steel In Used Fuel Container Environments, Dan Guo Dec 2018

Corrosion Dynamics Of Carbon Steel In Used Fuel Container Environments, Dan Guo

Electronic Thesis and Dissertation Repository

The current Canadian used nuclear fuel container (UFC) design uses a pressure‑grade carbon steel (CS) vessel with its outer surface coated with a thin layer of copper. One concern regarding the structural integrity of the UFC design is the potential internal corrosion of the CS vessel. Moisture trapped inside a UFC could condense within the gap between the hemispherical head and the cylindrical body of the vessel. The internal UFC environment will be exposed to a continuous flux of ionizing radiation arising from the decay of radionuclides trapped in the used UO2 fuel matrix.

This thesis research project ...


Electrospun Collagen Fibers For Tissue Regeneration Applications, Ying Li Sep 2018

Electrospun Collagen Fibers For Tissue Regeneration Applications, Ying Li

Electronic Thesis and Dissertation Repository

Tissue engineering aims to regenerate damaged and deceased tissue by combining cells with scaffold made from an appropriate biomaterial and providing a conducive environment to guide cell growth and the formation or regeneration of new tissue or organ. While collagen, an important material of the extracellular matrix (ECM), is a natural choice as a scaffold biomaterial, the conducive environment can only be created by having the ability to control the geometry, organization, structural and mechanical properties of the scaffold. Moreover, degradability and degradation rate control of the scaffold has to be taken into consideration too. In this work, we aim ...


Chemical Modification Of Lignin Into Advanced Materials, Soheil Hajirahimkhan Aug 2018

Chemical Modification Of Lignin Into Advanced Materials, Soheil Hajirahimkhan

Electronic Thesis and Dissertation Repository

Fossil fuel resources are being used today for most of humankind’s energy and chemical/material needs. The inevitable demise of these resources has created significant interest in the field of biomass and particularly, lignin valorization. As the world’s second most abundant polymer, more than 98% of the annually produced lignin is under-utilized either as an on-site heat source, or as landfill. Thus, finding practical approaches to modifying this inexpensive sustainable resource into materials of high value can be the next leap in lessening the dependence on fossil fuel resources and thus, developing a sustainable future.

In this thesis ...


Microinjection Molding Of Carbon Filled Polymer Composites, Shengtai Zhou Aug 2018

Microinjection Molding Of Carbon Filled Polymer Composites, Shengtai Zhou

Electronic Thesis and Dissertation Repository

There has been increasing demand for microparts in the areas of electronics, automotive, biomedical and micro-electro-mechanical systems. Microinjection molding (μIM) is becoming an important technology to fabricate miniature products or components to satisfy the ever-increasing needs of the above industries. Polymers and polymeric composites are ubiquitously adopted as molding materials due to their weight advantage, good processability and excellent resistance to corrosion.

Earlier studies have been primarily focused on the μIM of unfilled thermoplastics; however, microparts with multi-functionalities, such as electrical, thermal and mechanical properties are always accommodated by using multi-functional filler loaded polymer composites. Recently, μIM of carbon nanotubes ...


Sources Of Glass Transition Temperature Variation In Poly(Methyl Methacrylate)/Cellulose Composites, Elena Mamycheva Jun 2018

Sources Of Glass Transition Temperature Variation In Poly(Methyl Methacrylate)/Cellulose Composites, Elena Mamycheva

Electronic Thesis and Dissertation Repository

Variation in glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) is addressed, specifically for composites of poly(methyl methacrylate) (PMMA) and freeze-dried cellulose nanocrystals; mortar-and-pestle grinding use for creating solventless PMMA/cellulose nanocomposites is evaluated. Experimentally, solvent-containing and solventless PMMA and PMMA/cellulose composite samples (prepared using mortar-and-pestle grinding, melt-pressing, and acetone addition) were tested by DSC in hermetically-sealed pans using one of two maximum first heating scan temperatures; post-DSC samples were photographed. Mortar-and-pestle-ground cellulose was imaged by Field Emission Scanning Electron Microscopy (FE-SEM). Post-DSC samples had different shapes, some corresponding to greater increases in Tg from first ...


Effect Of Material Viscoelasticity On Frequency Tuning Of Dielectric Elastomer Membrane Resonators, Liyang Tian Jun 2018

Effect Of Material Viscoelasticity On Frequency Tuning Of Dielectric Elastomer Membrane Resonators, Liyang Tian

Electronic Thesis and Dissertation Repository

Dielectric elastomers (DEs) capable of large voltage-induced deformation show promise for applications such as resonators and oscillators. However, the dynamic performance of such vibrational devices is not only strongly affected by the nonlinear electromechanical coupling and material hyperelasticity, but also significantly by the material viscoelasticity. The material viscoelasticity of DEs originates from the highly mobile polymer chains that constitute the polymer networks of the DE. Moreover, due to the multiple viscous polymer subnetworks, DEs possess multiple relaxation processes. Therefore, in order to predict the dynamic performance of DE-based devices, a theoretical model that accounts for the multiple relaxation processes is ...


Development And Applications Of Polyglyoxylate Self-Immolative Polymers, Bo Fan Apr 2018

Development And Applications Of Polyglyoxylate Self-Immolative Polymers, Bo Fan

Electronic Thesis and Dissertation Repository

Self-immolative polymers (SIPs) are relatively recent class of stimuli-responsive and degradable polymers that have attracted significant attention in the past several years. SIPs consist of polymer backbones and stimuli-responsive end-caps at one or both polymer termini. Upon detection of a stimulus, the decomposition of the end-cap leads to complete end-to-end depolymerization. Polyglyoxylates were introduced as a new class of polyacetal based SIPs by our group in 2014. Compared with other SIPs, polyglyoxylates have two advantages including: 1) readily available monomers and 2) low toxic depolymerization products. These advantages may allow polyglyoxylates to be used in a wide range of applications ...


Mechanical Characterization And Shear Test Comparison For Continuous-Fiber Polymer Composites, Matthew Crossan Apr 2018

Mechanical Characterization And Shear Test Comparison For Continuous-Fiber Polymer Composites, Matthew Crossan

Electronic Thesis and Dissertation Repository

As fiber-reinforced composites continue to be used in a wide-range of high performance structures, more detailed understanding and accurate prediction of stress-strain behaviour is necessary to improving designs and reducing costs. This thesis compares the experimental behaviour of a continuous fiber polymer composite of carbon fiber and epoxy resin using Digital Image Correlation to analytical and theoretical predictions. Furthermore, an in-depth analysis of shear testing methods reveals the advantages and limitations of different testing standards. Finally, the limitations of the Iosipescu Shear test (ASTM 5379) fixture to break high-strain-to-failure composites in comparison to the V-notched Rail Shear Fixture (ASTM 7078 ...


Development Of Nanostructures By Atomic And Molecular Layer Deposition, Andrew P. Lushington Apr 2018

Development Of Nanostructures By Atomic And Molecular Layer Deposition, Andrew P. Lushington

Electronic Thesis and Dissertation Repository

Atomic layer deposition (ALD) is a thin film deposition technique that has a rich history of being an enabling technique. This vapor phase deposition process can produce a variety of thin films and nanostructures. ALD is based on sequential, self-limiting reactions and provides angstrom level control over film growth. Furthermore, ALD allows for conformal deposition on high-aspect ratio structures and can provide tunable film composition. As nanotechnology marches forward, the development of nanomaterials has significantly advanced. Additional functionality can be imparted to nanomaterials by using surface modification techniques. Given the advantages of ALD, this technique has become a powerful tool ...


Fabrication Of 3d Conjugated Polymer Structures Via Vat Polymerization Additive Manufacturing, Andrew T. Cullen Apr 2018

Fabrication Of 3d Conjugated Polymer Structures Via Vat Polymerization Additive Manufacturing, Andrew T. Cullen

Electronic Thesis and Dissertation Repository

Conjugated polymers are a class of electromechanically active materials that can produce motion in response to an electric potential. This motion can be harnessed to perform mechanical work, and therefore these materials are particularly well suited for use as sensors and actuators in microelectromechanical systems. Conventional methods to fabricate conjugated polymer actuators result in planar morphologies that limit fabricated devices to simplistic linear or bending actuation modes. To overcome this limitation, this work develops a conjugated polymer formulation and associated additive manufacturing method capable of realizing three-dimensional conductive polymer structures. A light-based additive manufacturing technique known as vat polymerization is ...


Study On The Surface Features Of Preg-Robbing Carbonaceous Matter During Oxidation Treatment, Mana Pourdasht Mar 2018

Study On The Surface Features Of Preg-Robbing Carbonaceous Matter During Oxidation Treatment, Mana Pourdasht

Electronic Thesis and Dissertation Repository

Carbonaceous gold ores have the ability to adsorb gold (I) cyanide from leach solutions during processing. This phenomenon, known as preg-robbing, is responsible for poor recoveries as the carbonaceous materials of the ore compete with activated carbon used during the leaching and adsorption phase of processing. Chemical oxidation of carbonaceous materials by different reagents has been utilized to investigate and compare the mechanism of Au (CN)2 adsorption onto carbonaceous materials prior to and following the treatment.

The procedure for characterization of the carbonaceous materials (plain and modified) in the sample combines the use of several analytical techniques and test ...


Covalently Crosslinked Organic/Inorganic Hybrid Biomaterials For Bone Tissue Engineering Applications, Dibakar Mondal Feb 2018

Covalently Crosslinked Organic/Inorganic Hybrid Biomaterials For Bone Tissue Engineering Applications, Dibakar Mondal

Electronic Thesis and Dissertation Repository

Scaffolds are key components for bone tissue engineering and regeneration. They guide new bone formation by mimicking bone extracellular matrix for cell recruitment and proliferation. Ideally, scaffolds for bone tissue engineering need to be osteoconductive, osteoinductive, porous, degradable and mechanically competent. As a single material can not provide all these requirements, composites of several biomaterials are viable solutions to combine various properties. However, conventional composites fail to fulfil these requirements due to their distinct phases at the microscopic level. Organic/inorganic (O/I) class II hybrid biomaterials, where the organic and inorganic phases are chemically crosslinked on a molecular scale ...


Adaption Of Catechol And Reversible Addition-Fragmentation Chain-Transfer (Raft) Chemistries For Water-Based Applications, Olabode Oyeneye Dec 2017

Adaption Of Catechol And Reversible Addition-Fragmentation Chain-Transfer (Raft) Chemistries For Water-Based Applications, Olabode Oyeneye

Electronic Thesis and Dissertation Repository

Incorporating the binding chemistry of catechol functionality with RAFT chemistry offers a facile and simplified approach for developing a suite of new 2D and 3D hybrid materials with tailored morphologies. Leveraging both chemistries by synthesizing catechol-end functionalized RAFT agents and catechol-containing monomeric species for RAFT (co)polymerization, this dissertation examined a new series of advanced materials that were designed for water-based applications including model flocculants, thermoresponsive hydrogels, adsorbents and underwater adhesives.

To prepare the RAFT agents, novel trithiocarbonates with several catechol end R groups (as postpolymerization anchors) were synthesized that differ in their carbonyl α-substituents (Dopa-CTAs). These materials were evaluated ...


Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed Dec 2017

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of ...


Gamma-Radiation Induced Corrosion Of Alloy 800, Mojtaba Momeni Nov 2017

Gamma-Radiation Induced Corrosion Of Alloy 800, Mojtaba Momeni

Electronic Thesis and Dissertation Repository

This thesis presents a newly developed mechanism and predictive model for the corrosion of Alloy 800. The Fe-Cr-Ni Alloy (Incoloy 800) is mainly used for steam generator (SG) tubing in CANDU and PWR reactors and is a candidate material for the proposed Canadian Supercritical Water Reactor (SCWR) in which it will be exposed to extreme conditions of high radiation flux and large temperature gradients. The influence of gamma radiation and water chemistry conditions on the corrosion behaviour of Alloy 800 are studied in this work. Ionizing radiation creates reducing (•eaq, •H, •O2-) and oxidizing radiolysis (•OH, H2 ...


Development Of Nanomaterials For Lithium-Ion Batteries By Atomic Layer Deposition, Biqiong Wang Oct 2017

Development Of Nanomaterials For Lithium-Ion Batteries By Atomic Layer Deposition, Biqiong Wang

Electronic Thesis and Dissertation Repository

Lithium ion batteries (LIBs) have been the dominant candidate in the field of energy storage. The ever-growing demand of high energy and power density, longer battery life, and more assured safety level has geared the development of LIBs towards all-solid-state batteries (ASSBs). The solid-state nature allows more flexibility in battery design and higher area capacity to be obtained within limited space. Moreover, replacing liquid electrolytes with solid-state electrolytes (SSEs) is a most effective approach to achieve safer battery system. In addition, ASSBs hold great promise in the actual fabrication of microbatteries for microelectronics. Therefore, a technique which can synthesize materials ...


Advanced Materials For Lithium Ion Batteries:Surface And Interface Chemistry, Yulong Liu Oct 2017

Advanced Materials For Lithium Ion Batteries:Surface And Interface Chemistry, Yulong Liu

Electronic Thesis and Dissertation Repository

Lithium ion batteries (LIBs) are the indispensable energy storage devices in our modern society. LiFePO4, as one of the most promising cathode, are widely used in LIBs. However, impurity phases are formed in LiFePO4 during carbon coating process due to the intrinsic strong reducing atmosphere. Herein, as the first part of my work, interface chemistry of carbon coating on LiFePO4 are symmetrically investigated by advanced characterization techniques. Two distinct secondary phases are formed during carbon coating process at different condition. Moreover, secondary phase formation is controllable by changing the particle size of LiFePO4, annealing temperature, and ...


Development Of High-Performance Carbon And Phosphorus Anode Materials For Sodium-Ion Batteries, Wei Xiao Oct 2017

Development Of High-Performance Carbon And Phosphorus Anode Materials For Sodium-Ion Batteries, Wei Xiao

Electronic Thesis and Dissertation Repository

Abstract

Lithium-ion batteries, as dominant power sources for prevailing consumer electronics and electric vehicles, have been plagued by limited lithium resources with the soaring prices. Sodium-ion batteries, benefitted from ubiquitous and inexpensive sodium resources without toxicity and pollution, have emerged as promising alternatives for large-scale applications. Considering their kinetic challenges and disadvantageous energy densities, it is urgently necessary to pursue high-performance electrode materials to remedy these intrinsic defects. For anode materials, the primary choices of sodium metal and graphite are correspondingly denied for safety issues and intercalation incapability. Therefore, the objective for this doctoral work is to develop high-performance anode ...


3d Printing Of Functional Materials: Surface Technology And Structural Optimization, Dongxing Zhang Sep 2017

3d Printing Of Functional Materials: Surface Technology And Structural Optimization, Dongxing Zhang

Electronic Thesis and Dissertation Repository

There has been a surge in interest of 3D printing technology in the recent 5 years with respect to the equipment and materials, because this technology allows one to create sophisticated and customized parts in a manner that is more efficient regarding both material and time consumption. However, 3D printing has not yet become a mainstream technology within the established manufacturing routes. One primary factor accounting for this slow progress is the lack of a broad variety of 3D printable materials, resulting in limited functions of 3D printed parts.

To bridge this gap, I present an integrated strategy to fabricate ...


Effects Of Lignin As A Stabilizer Or Antioxidant In Polyolefins, Afsana S. Kabir Aug 2017

Effects Of Lignin As A Stabilizer Or Antioxidant In Polyolefins, Afsana S. Kabir

Electronic Thesis and Dissertation Repository

Lignin, a major component of biomass, is an attractive alternative to hindered phenol-based antioxidants for polymers due to its renewable nature and naturally occurring hindered phenolic structure. In this study, for the first time, lignin de-polymerization was explored as a promising approach to improve the reactivity of the lignin-based antioxidants for polymers (polyethylene, PE and polypropylene, PP). A proprietary hydrolytic de-polymerization process was utilized to increase the antioxidant activity of two types of technical lignin: kraft lignin, KL (a by-product from the pulp and paper industry) and hydrolysis lignin, HL (a by-product from the pre-treatment processes in cellulosic ethanol plants ...


Additive Manufacturing Process Of 3d Polyaniline Transducers Via Direct Ink Writing, Frederick Benjamin Holness Aug 2017

Additive Manufacturing Process Of 3d Polyaniline Transducers Via Direct Ink Writing, Frederick Benjamin Holness

Electronic Thesis and Dissertation Repository

Electroactive polymers exhibit a change in properties, typically size or shape, in response to electrical stimuli. One class of electroactive polymer of particular interest are the conjugated polymers, whose conjugated backbone structure imparts electrical conductivity. However, this structure imposes processing limitations restricting their form to 2D structures. To overcome this, we develop specially formulated polyaniline- based blends via counter-ion induced thermal doping for the fabrication of 3D conductive structures via direct ink writing. This approach employs multi-material extrusion for the production of structures with passive and active features, rapid device fabrication, and improved design freedom. A model of the thermal ...


Fabrication And Characterization Of Hybrid Nanocomposites By Matrix Assisted Pulsed Laser Evaporation, Songlin Yang Aug 2017

Fabrication And Characterization Of Hybrid Nanocomposites By Matrix Assisted Pulsed Laser Evaporation, Songlin Yang

Electronic Thesis and Dissertation Repository

Different methods have been applied to deposit hybrid nanocomposites which can be applied in various fields due to their light weight and multifunctional properties. Here, matrix assisted pulsed laser evaporation (MAPLE) equipment with 532 nm Nd:YAG laser is applied to fabricate three types of hybrid nanocomposites on different substrates.

Chemical synthesized FeCo nanoparticles were deposited on graphene sheets by MAPLE technique (laser fluence: 300 mJ/cm2). The effects of deposition time (t) on particle amount, shape and size have been investigated. Yttrium barium copper oxide (YBCO) materials are one type of high-temperature superconductive materials and could be applied ...


Thermal Kinetics Of Helium Irradiation Hardening In Selected Alloys For The Canadian Gen. Iv Nuclear Reactor Concept, Feifei Nie May 2017

Thermal Kinetics Of Helium Irradiation Hardening In Selected Alloys For The Canadian Gen. Iv Nuclear Reactor Concept, Feifei Nie

Electronic Thesis and Dissertation Repository

In this thesis, we present nano-indentation measurements performed to quantify the increase in hardness as a result of He+ and Fe4+ implantation in both Inconel 800H and AISI 310 alloys. After annealing, the softening rate of He+ and Fe4+ implanted samples were compared, and it is found that Ni can slow the helium diffusion. Thermal activation energy Q characterizing this process was similar to the computed thermal activation energy QHe for interstitial helium diffusion within pure nickel. Indentation hardness tests were also performed at various indentation strain rates, to further study the effect of implanted helium as ...