Engineering Commons^™

Enhanced Performance Of 3d Electroactive Polymer Transducers Via Hierarchical Structures, Frederick B. Holness

Electronic Thesis and Dissertation Repository

Conjugated polymers (CPs) are a class of polymers that exhibit a change in size or shape in response to electrical stimuli. The unique combination of electrical and mechanical properties facilitates the fabrication of novel devices in a broad range of applications including: sensors, actuators, and lab-on-a-chip systems. The alternating single and double bonds along the polymer chain of CPs enables their electroactive properties but is also responsible for processability associated with CPs that has limited fabrication methods. Recently a photosensitive CP composite enabling additive manufacturing (AM) of 3D CP structures was developed. However, the introduction of a copolymer for mechanical …

Near-Ir Laser Ablation Of Simulated Radiologically Contaminated Oxides On Carbon Steel Feeder Pipes, Thao Viet Do

Electronic Thesis and Dissertation Repository

As nuclear power plants age and retire from service, many countries face significant challenges concerning the safe long-term storage and disposal of large volumes of low and intermediate level radioactive wastes (L&ILW). The volumes of metallic waste are of particular concern, as when metal corrodes it produces hydrogen that could lead to pressure build-up in interim storage and disposal. In Canada, a significant fraction of the metallic wastes for Canada Deuterium Uranium (CANDU) nuclear reactors are out-of-core reactor components, such as carbon steel (CS) feeder pipes. The radioactive contamination is expected to be largely confined to the surface oxide layers …

Highly Efficient De-Lignification And Reengineering Approach To Modify Wood Into A Bio-Composite And An Adsorbent Material, Ramon Filipe Beims

Electronic Thesis and Dissertation Repository

In this doctoral study, high-value bio-based materials, including a light-weight and high-strength wood-based composite material and a bio-based adsorbent material for removal of heavy metals in water, were developed from natural wood by a novel reengineering approach. In this approach, natural wood was first fractionated into a porous de-lignified wood and lignin. The porous de-lignified wood was then composited by impregnation of an epoxy resin synthesized with the lignin extracted from wood.

The wood-based composite preparation consisted of three main steps: (i) de-lignification of natural wood, (ii) lignin modification and epoxidation, and (iii) impregnation of the de-lignified wood with lignin-based …

Thermo-Responsive Antibiotic-Eluting Coatings For Treating Infection Near Orthopedic Implants, Jan Chung Kwan

Electronic Thesis and Dissertation Repository

The clinical effectiveness of orthopedic devices to restore the function of joints has been well established yet there is a lack of development in associated infections. As the demand for orthopedic surgeries continues to rise, infection remains a growing problem and one of the main reasons for revision surgeries. Bacterial contamination of the surgical site followed by adhesion of bacteria onto the surface of orthopedic devices leads to the formation of a biofilm which is a common initiator for infection. As a result, infection in the orthopedic field is commonly defined as orthopedic device-related infections (ODRI). There are limited options …

Development Of Anti-Corrosive Polyester Powder Coatings, Marshall Shuai Yang

Electronic Thesis and Dissertation Repository

Powder coatings are green solutions to replace the environmentally unfriendly liquid paints for anti-corrosive purpose. In this study, UV-resistant polyester/TGIC powder coatings for outdoor application were developed instead of the widely used epoxy-based coatings. Three types of additives and functional filler, namely zinc phosphate with passivation effect, zinc powder with sacrificial anode effect, and two nanoclays with barrier effect were incorporated into the coatings to enhance the anti-corrosive performance. The anti-corrosive properties were evaluated by electrochemical techniques and neutral salt spray tests. The combined effects of the additives with a filler barium sulfate were also investigated. The effect of the …

Three-Dimensional Fluid Interface Manipulation With Printed Structures For Applications In Materials, Chemistry, And Biomedical Engineering, Yiyuan Zhang

Electronic Thesis and Dissertation Repository

Fluid interfaces, including gas-liquid and liquid-liquid interfaces, are ubiquitous in nature and widely used in industrial applications. Many fundamental physical and chemical processes, such as evaporation, diffusion, adsorption, reaction, instability, and acoustic resonance, occur at the fluid interfaces, which form the pivot of chemistry, physics, biology, and material science. Engineering the fluid interface in a flexible manner can be very attractive for interfacial process research and technological renovations. To control fluid interface, numerous fluid manipulation methods have been developed. However, they still face great challenges in precise 3D fluid manipulation, including 1. lack of general methods to create structured 3D …

Solid Electrolytes And Interface Design For High-Performance All-Solid-State Batteries, Shumin Zhang

Electronic Thesis and Dissertation Repository

All-solid-state batteries (ASSBs), in which solid superionic conductors are used as electrolytes to transport ions between cathode and anode, have been regarded as one of the most promising candidates for the next-generation energy storage technologies in electric vehicles (EVs), grid applications, etc. The advances of ASSBs over conventional lithium-ion batteries (LIBs) come from their inherent safety and high energy density, which benefits from the use of nonflammable solid electrolytes (SEs) to potentially enable metal anodes (such as Li metal or Na metal) and high-voltage cathode active materials (CAM) in ASSBs. Since that, the research and design of SEs have been …

Damage In Non-Crimp Fabric Carbon Fiber Reinforced Epoxy Composites Under Various Mechanical Loading Conditions, Aaditya Pradeep Suratkar

Electronic Thesis and Dissertation Repository

Composite materials have emerged in the recent years as a frontrunning lightweight replacement for metals for structural applications in lightweight automobiles. However, the key adoption criteria for composites in lightweight vehicles is their crashworthiness, i.e., the amount of energy a structure made with composites would absorb in a crash event. The energy is absorbed in composites through various damage modes such as matrix cracks, delamination, fiber breakage, etc. Therefore, adoption of a certain composite material system requires thorough understanding of the initiation and propagation of damage until failure in that system under various mechanical loading conditions, which is also the …

Hydration Kinetics, Microstructure, And Mechanical Strength Development Of Cement-Based Composites Incorporating Phase Change Materials, Afshin Marani

Electronic Thesis and Dissertation Repository

The research conducted in this thesis investigates the effects of phase change materials (PCMs) on the hydration kinetics and strength development of cement-based composites using extensive experimental and numerical analyses. Purposefully, the effect of microencapsulated PCMs (MPCMs) on the strength development of cement-based mortars and concretes was evaluated using powerful machine learning models trained with the largest available experimental data. Furthermore, a novel ternary machine learning approach was proposed to optimize the mixture design of mortars and concretes based on the thermos-physical properties of the MPCMs. The results obtained from machine learning simulations suggest the assessment of the effects of …

On The Effects Of Additive Manufacturing Process Parameters On The Performance Of Hastelloy-X: A Neutron Diffraction Experiment And Crystal Plasticity Finite Element Model, Ahmed Aburakhia

Electronic Thesis and Dissertation Repository

Additive manufacturing (AM) is increasingly becoming one of the favourable manufacturing techniques in various industries, such as transportation and energy. The reason for the extensive use of AM lies in the ability to use a wide range of process parameters for manufacturing engineering parts with complex geometries that cannot be effectively manufactured using traditional methods such as casting or forging. Understanding the role of process parameters is crucial for developing predictive models, as well as for manufacturing engineering components with the desired properties.

This research aims to characterize the influence of AM process parameters on the deformation mechanisms of Hastelloy-X, …

Development Of High Performance Cathodes: From Liquid To Solid-State Batteries, Sixu Deng

Electronic Thesis and Dissertation Repository

Lithium-ion batteries (LIBs) are critical for the development of electric vehicles (EVs) because of their higher operating voltages compared to other energy storage technologies. However, the development of start-of-the-art LIBs touched the ceiling because of three main challenges: safety risks, limited energy density, and high cost. Accordingly, all-solid-state lithium-ion batteries (ASSLIBs) have recently emerged as promising alternative batteries for next-generation EVs because of their ability to overcome the drawbacks of conventional LIBs. Whether in conventional liquid LIBs or ASSLIBs, cathode materials are crucial in determining the overall performance. Hence, this thesis focuses on understanding the degradation mechanism of cathode interfaces …

Sol-Gel Derived Bioceramic Poly(Diethyl Fumarate – Co – Triethoxyvinylsilane) Composite, Aref Sleiman

Electronic Thesis and Dissertation Repository

Synthetic bone graft materials have become an increasingly popular choice for bone augmentation. Ceramic-based and polymer-based bone graft materials constitute the two main classes of synthetic bone graft materials. This study investigated the synthesis of novel bioactive composites for their potential use as bone graft biomaterials. Poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic class II organic/inorganic hybrid biomaterials were synthesized via a sol gel process. These biomaterials were then reacted with an ammonium phosphate solution to prepare their respective composites. For the first time, we successfully synthesized sol-gel derived bioceramic poly(diethyl fumarate-co-triethoxyvinylsilane) composites. In vitro bioactivity evaluation of poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic composites in simulated body fluid …

Material Characterization Of Compression Molded Composites, Broderic Clement-Thorne

Electronic Thesis and Dissertation Repository

Composite materials are widely used in the automotive industry to keep cost and weight down. The ability to simulate the fabrication of parts is an important way to use resources effectively. The molding process can also have very dramatic effects on material properties. These properties are determined by the microstructure of the polymer composite material, including the length, concentration, and orientation of the fibers used as reinforcement. Therefore this study seeks to characterize the material properties of a long glass fiber reinforced polyamide composite, the effects of molding conditions on those material properties, and characterization of the microstructure of the …