Engineering Commons^™

Polyhydroxybutyrate Production In A Photobioreactor Using Spirulina Platensis, Adrianna Mika

Electronic Thesis and Dissertation Repository

Biopolymers and other naturally derived chemicals continue to gain attention over petrochemical based products due to the price volatility of crude oil, increasing need to reduce greenhouse gas emissions and public awareness of environmental issues. Cyanobacterium Spirulina (Arthrospira) platensis, a commercially feasible blue-green alga, is able to synthesize poly(3-hydroxybutyrate) (PHB), a biodegradable and biocompatible polymer, as an energy storage product of photosynthesis directly from CO₂. A flat plate photobioreactor (PBR) with LED illumination was designed for the cultivation of S. platensis. Computational fluid dynamics (CFD) software was used to improve airflow uniformity and mixing in the …

The Role Of Bone Sialoprotein In Periodontal Tissue Development And Bone Repair, Yohannes Soenjaya

Electronic Thesis and Dissertation Repository

Bone development and repair involve complex processes that include interaction between cells and their surrounding matrix. In the body, bone sialoprotein (BSP) expression is up-regulated at the onset of mineralization. BSP is a multifunctional acidic phosphoprotein with collagen-binding, hydroxyapatite nucleating, and integrin recognition (RGD sequence, which is important for cell-attachment and signaling) regions. Mice lacking BSP expression (Bsp^-/-), exhibit a bone phenotype with reductions in bone mineral density, bone length, osteoclast activation, and impaired bone healing. This thesis examined the role of BSP in tooth development and also its potential use as a therapeutic reagent for bone …

Security Protocol Suite For Preventing Cloud-Based Denial-Of-Service Attacks, Marwan M. Darwish

Electronic Thesis and Dissertation Repository

Cloud systems, also known as cloud services, are among the primary solutions of the information technology domain. Cloud services are accessed through an identity authentication process. These authentication processes have become increasingly vulnerable to adversaries who may perform denial-of-service (DoS) attacks to make cloud services inaccessible. Several strong authentication protocols have been employed to protect conventional network systems. Nevertheless, they can cause a DoS threat when implemented in the cloud-computing system. This is because the comprehensive verification process may exhaust the cloud resources and shut down cloud’s services. This thesis proposes a novel cloud-based secure authentication (CSA) protocol suite that …

Slope Stability Enhancement Of An Upstream Tailings Dam: Laboratory Testing And Numerical Modelling, Yazeed A. Alsharedah

Electronic Thesis and Dissertation Repository

Mine tailings are the byproduct of mining activities, which need to be disposed of once the ore is extracted. They can be disposed of in either dry or wet forms. The latter is most common with the tailings being disposed of in the form of slurry inside retention structures. The retention structure may be a natural, manmade, or built dam, which is the case in most of nowadays mining locations. In this thesis, improving the stability of an upstream tailings dam using soil additives is investigated. The experimental phase of this study involved laboratory tests conducted to characterize mine tailings …

Towards The Development Of A Wearable Tremor Suppression Glove, Yue Zhou

Electronic Thesis and Dissertation Repository

Patients diagnosed with Parkinson’s disease (PD) often associate with tremor. Among other symptoms of PD, tremor is the most aggressive symptom and it is difficult to control with traditional treatments. This thesis presents the assessment of Parkinsonian hand tremor in both the time domain and the frequency domain, the performance of a tremor estimator using different tremor models, and the development of a novel mechatronic transmission system for a wearable tremor suppression device. This transmission system functions as a mechatronic splitter that allows a single power source to support multiple independent applications. Unique features of this transmission system include low …

Silver Nanoparticle Transport Through Soil: Illuminating The Governing Pore-Scale Processes, Ian L. Molnar

Electronic Thesis and Dissertation Repository

Engineered nanoparticles are widely used and will eventually be released to the subsurface environment and contaminate groundwater resources. However, the transport of engineered nanoparticles through soil is currently not well understood and cannot be modelled in any fundamental manner, placing groundwater resources at risk from nanoparticle contamination. This inability to accurately simulate transport is due to a lack of experimental information on nanoparticle interactions in the pore spaces of real soils.

This thesis illuminates the pore-scale processes governing silver nanoparticle transport through soil. In addition, it examines the influence of surface chemistry and grain/pore distributions on those processes. For the …

Smouldering Remediation: Transient Effects Of Front Propagation, Laura L. Kinsman

Electronic Thesis and Dissertation Repository

Remediation of sites contaminated with non-aqueous phase liquids (NAPLs) presents a significant challenge, particularly for complex and high molecular weight compounds such as coal tar and creosote. Self-sustaining Treatment for Active Remediation (STAR) is an innovative remediation technology based on the principles of smouldering combustion, which has shown potential for rapid destruction of source zone contaminants. The success of smouldering remediation has been previously demonstrated both at the laboratory and field scale, however, these studies have focused primarily on the overall degree of remediation. Laboratory column experiments were employed to identify key transient processes that have the potential to influence …

Investigation Of Hybrid Foundation System For Offshore Wind Turbine, Ahmed Mohamed Reda Abdelkader

Electronic Thesis and Dissertation Repository

Green energy resources are essential to meet the growing energy demands in the near future while reducing the effects of global warming. Offshore wind energy is one of the main efficient renewable energy sources which drive the ever increasing expansion of offshore wind farms globally. Wind energy technologies are improving making energy production more affordable, which helped Denmark, for example, to produce about 25% of its energy. One of the main challenges for offshore wind projects is the cost of foundation construction, which represents about 40% of the total cost. The investigated hybrid foundation system has the potential to reduce …

Formulation And Optimization Of Antimicrobial Surfaces Via Ultra-Fine Powder Coating, Rezwana Yeasmin

Electronic Thesis and Dissertation Repository

In a health care environment, surface bio-contamination is a constant risk and contributes to outbreaks of community-acquired and nosocominal infections. Faster surface die-off of pathogens on a surface can reduce the average surface population of these pathogens. Antimicrobial ultra-fine powder coated surfaces with high antimicrobial longevity including efficiency is a good option to reduce the surface bio-contamination. Different formulations were prepared with the additives containing silver as an active agent and a chosen type of metal ions as a protective agent incorporated into zeolites and their antimicrobial activity was analyzed against Escherichia coli (E.coli). Two natural zeolites, known as chabazites …

Spectrally-Accurate Algorithm For Flows In 3-Dimensional Rough Channels, Md Nazmus Sakib

Electronic Thesis and Dissertation Repository

In this work a spectrally accurate algorithm has been developed for the simulation of three-dimensional flows bounded by rough walls. The algorithm is based on the velocity-vorticity formulation and uses the concept of Immersed Boundary Conditions (IBC) for the enforcement of the boundary conditions. The flow domain is immersed inside a fixed computational domain. The geometry of the boundaries is expressed in terms of double Fourier expansions and boundary conditions enter the algorithm in the form of constraints. The spatial discretization uses Fourier expansions in the stream-wise and span-wise directions and Chebyshev expansions in the wall-normal direction. The algorithm can …

Doping Plasmon-Enhanced Tio2 With Zirconia To Improve Solar Energy Harvesting In Dye-Sensitized Solar Cells, Anastasia Pasche

Electronic Thesis and Dissertation Repository

Solar energy is a promising solution towards meeting the world’s ever-growing energy demand. Dye-sensitized solar cells (DSSCs) are hybrid organic-inorganic solar cells with potential for commercial application, but are plagued by inefficiency due to their poor sunlight absorption. Silver nanoparticles have been shown to enhance the absorptive properties of DSSCs, but their plasmonic resonance causes local hot spots, resulting in cell deterioration. This thesis studies the mitigation of thermal energy loss of plasmon-enhanced DSSCs by the co-incorporation of zirconia, a well-known thermostabilizer, into the cell’s photoactive material. TiO2 was also synthesized using green bio-sourced solvents in supercritical CO2 to compare …

Pyrolysis Based Biorefineries For The Production Of Fermentable Substrates, Luis Carlos Luque-Moreno

Electronic Thesis and Dissertation Repository

Fast pyrolysis is rapid thermal conversion process capable of transforming multiple feedstocks into various energy carriers, specifically pyrolysis oil, bio gas, and bio char. The oil phase is of high value due to its complex mixtures of organic molecules, along with large number of anhydrous carbohydrates, which can be easily transformed into glucose via acid hydrolysis. These carbohydrates can be either biocatalyzed into fuels and chemicals by microorganisms or converted after further treatment steps. However quantities of these carbohydrates in the oil are a function of feedstock composition and process parameters. The research presented in this thesis focuses on producing …

Efficient Scheduling Algorithms For Wireless Resource Allocation And Virtualization In Wireless Networks, Mohamad Kalil

Electronic Thesis and Dissertation Repository

The continuing growth in demand for better mobile broadband experiences has motivated rapid development of radio-access technologies to support high data rates and improve quality of service (QoS) and quality of experience (QoE) for mobile users. However, the modern radio-access technologies pose new challenges to mobile network operators (MNO) and wireless device designers such as reducing the total cost of ownership while supporting high data throughput per user, and extending battery life-per-charge of the mobile devices. In this thesis, a variety of optimization techniques aimed at providing innovative solutions for such challenges are explored.

The thesis is divided into two …

Fundamentals Of The Biomechanical Characteristics Related To The Loading Of Reverse Total Shoulder Arthroplasty Implants And The Development Of A Wear Simulation Strategy, G Daniel G. Langohr

Electronic Thesis and Dissertation Repository

A greater understanding of reverse total shoulder arthroplasty (RTSA) in terms of articular contact mechanics and wear is essential for the optimization of current surgical technique and future implant design. Despite the prevalence of RTSA for shoulder reconstruction, there is little information in current literature regarding the effects of changes in implant parameters on articular contact mechanics and wear. The present work describes the use of in-vitro cadaveric studies, a computational model of the articular contact surfaces, and the development and implementation of a wear simulation strategy to assess RTSA contact mechanics and wear.

The articular loading characteristics of RTSA …

Wireless Device Authentication Techniques Using Physical-Layer Device Fingerprint, Peng Hao

Electronic Thesis and Dissertation Repository

Due to the open nature of the radio signal propagation medium, wireless communication is inherently more vulnerable to various attacks than wired communication. Consequently, communication security is always one of the critical concerns in wireless networks. Given that the sophisticated adversaries may cover up their malicious behaviors through impersonation of legitimate devices, reliable wireless authentication is becoming indispensable to prevent such impersonation-based attacks through verification of the claimed identities of wireless devices.

Conventional wireless authentication is achieved above the physical layer using upper-layer identities and key-based cryptography. As a result, user authenticity can even be validated for the malicious attackers …

The Role Of Visualization, Force Feedback, And Augmented Reality In Minimally Invasive Heart Valve Repair, Maria E. Currie

Electronic Thesis and Dissertation Repository

New cardiovascular techniques have been developed to address the unique requirements of high risk, elderly, surgical patients with heart valve disease by avoiding both sternotomy and cardiopulmonary bypass. However, these technologies pose new challenges in visualization, force application, and intracardiac navigation. Force feedback and augmented reality (AR) can be applied to minimally invasive mitral valve repair and transcatheter aortic valve implantation (TAVI) techniques to potentially surmount these challenges. Our study demonstrated shorter operative times with three dimensional (3D) visualization compared to two dimensional (2D) visualization; however, both experts and novices applied significantly more force to cardiac tissue during 3D robotics-assisted …

Simulation Of Magnetic Field Induced Current And Neuron Spiking For Magnetic Seizure Therapy, Abhijeet R. Wadkar

Electronic Thesis and Dissertation Repository

Magnetic seizure therapy (MST) is currently on trial to treat severe cases of depression. This thesis is concerned with getting a deeper understanding of the mechanics behind MST by employing FEA of brain. The simulations performed via COMSOL helped identify the dimensions and coil types of the MST device as well as the angular probing orientations. Largest induced current due to the externally imposed magnetic field was found in the cerebrospinal fluid which was found to act as a barrier to induce current in the gray matter. In an attempt to relate the induced current to the neuron spiking, a …

Development Of An In-Vitro Passive And Active Motion Simulator For The Investigation Of Wrist Function And Kinematics, Duncan J. Iglesias

Electronic Thesis and Dissertation Repository

This thesis outlines the design and development of an active motion simulator for the investigation of wrist kinematics in multiple gravity loaded positions. Using optical trackers on the third metacarpal, radius, and ulna, the position of the wrist was monitored in real time without introducing material incompatibilities as present for electromagnetic tracking systems. Performance of the system was performed using a series of five cadaver upper limbs that compared the ability to produce repeatable trials using unrestrained active motion techniques over passive manipulation methods. Comparisons to achieve static positions as well as motion trials in flexion-extension and radial-ulnar deviation planes …

Adaptive Single-Phase Reclosing In Transmission Lines, Farzad Zhalefar

Electronic Thesis and Dissertation Repository

This research work is mainly concerned about dealing with temporary short circuit faults in power system transmission lines. In fact, there are two types of electrical faults in power systems, namely temporary and permanent. When a fault is permanent, the only way to clear it is to de-energize the transmission line by opening the associated circuit breakers. However, in many cases the fault is not solid and is caused by objects such as flying birds or broken branches of trees. For these cases, electrical arc plays a major role. For such fault cases, it is also possible to de-energize the …

Secrecy Enhancement In Cooperative Relaying Systems, Elham Nosrati

Electronic Thesis and Dissertation Repository

Cooperative communications is obviously an evolution in wireless networks due to its noticeable advantages such as increasing the coverage as well as combating fading and shadowing effects. However, the broadcast characteristic of a wireless medium which is exploited in cooperative communications leads to a variety of security vulnerabilities. As cooperative communication networks are globally expanded, they expose to security attacks and threats more than ever. Primarily, researchers have focused on upper layers of network architectures to meet the requirements for secure cooperative transmission while the upper-layer security solutions are incapable of combating a number of security threats, e.g., jamming attacks. …

On Enhancements Of Physical Layer Secret Key Generation And Its Application In Wireless Communication Systems, Kang Liu

Electronic Thesis and Dissertation Repository

As an alternative and appealing approach to providing information security in wireless communication systems, secret key generation at physical layer has demonstrated its potential in terms of efficiency and reliability over traditional cryptographic methods. Without the necessity of a management centre for key distribution or reliance on computational complexity, physical layer key generation protocols enable two wireless entities to extract identical and dynamic keys from the randomness of the wireless channels associated with them.

In this thesis, the reliability of secret key generation at the physical layer is examined in practical wireless channels with imperfect channel state information (CSI). Theoretical …

Analysis And Compensation Of Power Amplifier Distortions In Wireless Communication Systems, Sharath Manjunath

Electronic Thesis and Dissertation Repository

Wireless communication devices transmit message signals which should possess desirable power levels for quality transmission. Power amplifiers are devices in the wireless transmitters which increase the power of signals to the desired levels, but produce nonlinear distortions due to their saturation property, resulting in degradation of the quality of the transmitted signal. This thesis talks about the analysis and performance of communication systems in presence of power amplifier nonlinear distortions.

First, the thesis studies the effects of power amplifier nonlinear distortions on communication signals and proposes a simplified design for identification and compensation of the distortions at the receiver end …

Inkjet Printed Thin Film Electrodes For Lithium-Ion Batteries, Stephen D. Lawes

Electronic Thesis and Dissertation Repository

With the miniaturization of wireless electronics, the demand for ever-smaller energy storage devices has increased. Thin film batteries can meet this need by providing higher energy densities at smaller scales than conventional lithium-ion batteries. However, the fabrication of thin films batteries by vapor deposition methods typically involves expensive equipment and high temperatures, which limits their commercial application. This thesis reports the development of an inexpensive inkjet printing method of fabricating thin film electrodes for thin film lithium-ion batteries. Inks containing various electrode materials were first developed and optimized in terms of physical properties to ensure ideal jetting conditions. Then, thin …

Modeling, Construction, And Validation Of A Simulator For A Nuclear Process Control Test Facility, Binggang Cui

Electronic Thesis and Dissertation Repository

This thesis presents the modeling, construction, and validation of a software simulator for a facility with physical components, referred to as NPCTF (Nuclear Process Control Test Facility). The simulator focuses simulation functionalities on dynamic behaviours of thermal-hydraulic systems related to nuclear power plants.

The modeling techniques adopted to construct the simulator are based on physical principles. Dynamic models are developed to reproduce the dynamic characteristics of NPCTF. Based on these mathematical relationships, computer codes are developed with the toolbox Simscape. The simulator can be used to investigate specific scenarios of NPCTF under similar operating conditions.

A simulation environment, the toolbox …

Nanostructured Carbon Materials For Active And Durable Electrocatalysts And Supports In Fuel Cells, Adam Riese

Electronic Thesis and Dissertation Repository

Meeting the energy demands of the future will require a breadth of technologies and materials for generating and converting electricity. Increasing activity and reducing costs of electrocatalysts for fuel cells is among the most important challenges for the technology. With advances in nanomaterials there has been increased interest in creating novel catalysts with both high activity and excellent long-term durability. This thesis aims to understand how modification of nanostructured carbons can be used to improve the activity and durability of catalysts and supports for the oxygen reduction reaction (ORR). Using an integrating approach to synthesis, characterization, and electrochemical testing, it …

Flows In Vibrating Channels, Sahab Zandi

Electronic Thesis and Dissertation Repository

A spectral algorithm based on the immersed boundary conditions (IBC) concept has been developed for the analysis of flows in channels bounded by vibrating walls. The vibrations take the form of travelling waves of arbitrary profile. The algorithm uses a fixed computational domain with the flow domain immersed in its interior. Boundary conditions enter the algorithm in the form of constraints. The spatial discretization uses a Fourier expansion in the stream-wise direction and a Chebyshev expansion in the wall-normal direction. Use of the Galileo transformation converts the unsteady problem into a steady one. An efficient solver which takes advantage of …

Application Of 3d Printing Technology In Porous Anode Fabrication For Enhanced Power Output Of Microbial Fuel Cells, Bin Bian

Electronic Thesis and Dissertation Repository

Microbial fuel cells (MFCs) are widely researched for application in wastewater treatment. However, the current anodes used in MFCs often suffer from high fabrication cost and uncontrollable pore sizes. In this thesis, three-dimensional printing technique was utilized to fabricate anodes with different micro pore sizes for MFCs. Copper coating and carbonization were applied to the printed polymer anodes to increase the conductivity and specific surface area. Voltages of MFCs with various anodes were measured as well as other electrochemical tests such as linear sweep voltammetry and electrochemical impedance spectroscopy. 3D copper porous anode produced higher maximum voltages and power densities …

Shear And Peel Stresses At The Interface Between Hollowcore Slabs And The Topping Concrete, Aiham Adawi

Electronic Thesis and Dissertation Repository

Hollowcore slabs are used in floors and roofs of residential, commercial, industrial and institutional buildings. They are precast/prestressed concrete elements produced using the extrusion process. Their surface finish can be “machine-cast” or “intentionally roughened”. A typical floor consists of a number of hollowcore slabs that are connected together. Prestressing causes hollowcore slabs to camber, which results in an uneven floor surface. A 50 mm topping concrete is commonly cast to level the floor surface. To avoid delamination, engineers require bonding agents to be applied on the hollowcore slab surface before pouring the topping concrete. The concrete topping can be used …

Charging Level And Deposition Of Droplets In Electrostatic Painting, Husam Osman

Electronic Thesis and Dissertation Repository

The process of electrostatic painting has become a very important method of coating in a wide range of industrial applications including those used in the automobile industry. The general principle of spray coating is to deposit liquid droplets or solid powder particles on coated targets having various shapes. The electrostatic coating process consists of three main stages: droplet formation and charging, transportation and deposition. The complication of this process is caused by various factors, such as the physical properties of the material to be used, the appropriate electrical and mechanical conditions and the target surface to be coated, which affects …

Influence Of Waves On Groundwater Flows And Geochemistry In A Sandy Nearshore Aquifer: A Combined Field And Modelling Study, Spencer S. Malott

Electronic Thesis and Dissertation Repository

Waves are known to influence the flux of pollutants to coastal waters via groundwater discharge. This study combines field measurements with numerical groundwater modelling to evaluate the influence of a period of intensified wave conditions (wave event) on nearshore groundwater flows and geochemistry in a sandy freshwater beach. Comprehensive vertical nested pressure transducer data obtained over a 2.5 day isolated wave event reveal the development of transient groundwater flow recirculations through the nearshore aquifer combined with enhanced water exchange across the sediment-water interface (i.e., beach face). The wave-induced groundwater flows were simulated in FEFLOW using a phase-averaged wave setup approach …