Analyses For Assessing The Centreline Translation, Asymmetrical Wind-Field, And Velocity Fluctuations Of Tornado Vortices, Niall C. Bannigan

Electronic Thesis and Dissertation Repository

Tornadoes present an ever-increasing threat to communities worldwide, especially those with geographic conditions that place them in the path of several tornadoes annually. These conditions are likely to be exacerbated by ongoing trends in the climate. As such, it is necessary to move towards experimental and numerical tornado-like vortex studies that allow for more advanced simulation methods. Novel techniques for tracking and analysing tornado vortices simulated at high spatial and temporal resolution are presented herein. Significant wandering of the tornado's position and large peaks in the velocity field can be captured, demonstrating tangential gusting at more than 1.5 times the …

Study Of Multi-Dimensional Transfer Effects In Applied Smouldering Systems, Seyed Ziaedin Miry Mr

Electronic Thesis and Dissertation Repository

Smouldering is a flameless form of combustion that is driven by oxygen directly diffusing into the surface of condensed phase fuel (liquid or solid) and involves a complex interplay between heat and mass transfer through porous media, chemical reactions, and multiphase flow. Applied smouldering systems have been gaining popularity for a variety of applications including (i) energy and resource recovery, (ii) waste-to-energy, (iii) pyrolysis and gasification, and (iv) applied smouldering of organic liquids/solids for environmental benefits. In all contexts, smouldering is a complicated oxygen-limited phenomenon where multi-dimensional transfer effects (i.e., non-uniformities in …

Effect Of Land Use Type And Stormwater Control Measures On Non-Point Source Phosphorus Concentrations And Loads In A Cold Climate Urban Subwatershed, Dillon H. Vyn

Electronic Thesis and Dissertation Repository

Non-point source phosphorus (P) exports from urban areas including contributions from different urban land use types and seasonal variations are not well understood, especially for cold climates. Additionally, the effectiveness of different stormwater control measures (SCMs) in reducing P concentrations and loads are poorly quantified with assessments rarely considering total watershed P loads. To address these gaps, detailed field monitoring of total P (TP), soluble reactive P (SRP), total suspended solids (TSS), and water quantity was conducted over a 19-month period in a mixed urban watershed in London, ON. Monitoring sites were located at watershed outlets, at the outlets of …

Application Of Wavelet Analysis And Random Field In Integrity Management Of Pipelines Containing Dents And Corrosions, Junxiong Lin

Electronic Thesis and Dissertation Repository

Metal loss corrosions and dents are two major threats to the integrity of oil and natural gas pipelines. In the pipeline industry, the Fitness-For-Service (FFS) assessment is commonly employed for pipelines containing these defects. However, FFS assessment usually assumes that a defect has a simple shape, and such a simplification may significantly affect the accuracy of the assessment. Therefore, retaining the actual shapes of defects and incorporating them into the FFS assessment can improve assessment accuracy. The main objective of the present thesis is to extract key information about the sizes, directions, and shapes of corrosions and dents from the …

Parametric Analysis And Enhancement Of The Burst Capacity Model For Composite-Repaired Corroded Pipelines, Rodrigo Silva Silva-Santisteban

Electronic Thesis and Dissertation Repository

One of the main causes of pipeline failures is corrosion, which leads to a localized loss of the pipe wall thickness and hence compromises the capacity of the pipeline. Composite repair is a method to rehabilitate corroded pipelines. Design codes such as ASME PCC-2 are commonly used to design the repair thickness. As the predictive accuracy to determine the burst capacity of a composite repaired pipeline with existing models is generally poor, the main objective of the present thesis is to provide insights on the parameters that affect the burst capacity and propose improvements to the prediction of burst capacity …

Monitoring Remediation Of Organic Contaminants Using Electrical Resistivity And Induced Polarization Techniques, Angelos Almpanis

Electronic Thesis and Dissertation Repository

Effective characterization and monitoring of subsurface processes associated with the remediation of sites contaminated by dense non-aqueous phase liquids (DNAPLs) remains a substantial environmental challenge. Geophysical techniques such as direct current (DC) resistivity and induced polarization (IP) offer the potential to considerably enhance our understanding of such complex phenomena occurring in the subsurface. However, despite extensive research highlighting the benefits of employing IP – in the time domain (DCIP) and/or frequency domain (spectral IP, SIP) – for contaminant investigations, more research is needed to understand the role of IP for monitoring DNAPL remediation. The goal of this thesis was to …

Waveform Similarity Of Micro-Seismicity At The Toc2me Hydraulic Fracturing Experiment Site, Jin Yang

Electronic Thesis and Dissertation Repository

This thesis quantitatively investigates the waveform similarity of micro-earthquakes detected during the Tony Creek Dual Microseismic Experiment (ToC2ME) located in Fox Creek, Alberta. Subsurface anthropogenic activities, especially processes involving injection, can lead to accumulation of porepressure and elastic strain in the geologic formations and rocks, resulting in induced earthquakes. Four hydraulic-fracturing treatment wells were drilled and completed in the study area. The microseismic acquisition system monitored continuous seismic waveforms from 25 October to 15 December 2016 revealing 21619 hydraulic fracture-related events with magnitude ranging from Mw -1 to 3.2. The present study compares and discusses similarity of waveforms captured by …

Wind Loading Analysis Of Standing Seam Metal Roofs On Low-Rise Buildings, Ellen J. Marejka

Electronic Thesis and Dissertation Repository

Standing seam metal roofs (SSMR) are a roofing system made up of prefabricated panels secured to the underlying structural purlins using concealed clips. The present study sought to develop a simplified code-approach for evaluating SSMRs. A model of the wind field and wind loads was validated using wind tunnel data from Arif (2017), influence functions and clip layout from Xia (2022), and compared the results to ASCE 7-22. Worst case enveloped GCp were compared by area for three different models: (i) ASCE Method, which gives wind loads based on bare deck roof, (ii) Clip Tributary Area (CTA) Method, which assumed …

Effect Of Morphology And An Upstream Tall Building On A Street Canyon Flow, Haoran Du

Electronic Thesis and Dissertation Repository

The effects of the morphological model and the existence of an upstream tall building on the turbulent street canyon flow and the overlying boundary layer are investigated in a wind tunnel, using Stereoscopic Particle Image Velocimetry (S-PIV) measurements. The velocity variances, Reynolds shear stress, and turbulent kinetic energy are found to be larger than in a similar idealized street canyon model. Increasing building height results in a decrease in vertical mass fluxes across the opening of the canyon, at least in the canyon portion directly downstream of the building. The interaction between the large-scale structures in the overlying boundary layer …

Geoelectrical Signatures Of Acid-Generating Mine Waste Rock, Difan Su

Electronic Thesis and Dissertation Repository

Acid mine drainage (AMD) contamination associated with waste rock piles (WRPs) at mining sites is a global concern, and understanding the generation and release of AMD from these piles is highly desirable. Traditional WRP monitoring techniques involve the installation of monitoring wells and periodic core sampling; however, these approaches are invasive, expensive and can only provide data with limited spatial and temporal resolution. An attractive alternative is non-invasive geophysical techniques that can provide non-invasive and continuous information on subsurface features and processes. This thesis aims to investigate the feasibility of the spectral induced polarization (SIP) method for monitoring changes in …

Autonomous 3d Urban And Complex Terrain Geometry Generation And Micro-Climate Modelling Using Cfd And Deep Learning, Tewodros F. Alemayehu

Electronic Thesis and Dissertation Repository

Sustainable building design requires a clear understanding and realistic modelling of the complex interaction between climate and built environment to create safe and comfortable outdoor and indoor spaces. This necessitates unprecedented urban climate modelling at high temporal and spatial resolution. The interaction between complex urban geometries and the microclimate is characterized by complex transport mechanisms. The challenge to generate geometric and physics boundary conditions in an automated manner is hindering the progress of computational methods in urban design. Thus, the challenge of modelling realistic and pragmatic numerical urban micro-climate for wind engineering, environmental, and building energy simulation applications should address …

Effects Of Wind Turbine Rotor Positioning On Tornado Induced Loads, Juan P. Lopez Ortiz

Electronic Thesis and Dissertation Repository

This study investigates the loads induced by a large-scale tornado simulation on a horizontal axis wind turbine (HAWT) to assess the influence of three-dimensional flows with respect to the HAWT position. The loads were analyzed under two rotor operational conditions, idling and parked, at five radial distances. Subsequently, experimental validation of the numerical code HIW-TUR was conducted by evaluating the induced moments for various yaw and pitch angles. The experimental results demonstrated that the bending moment was the most important in terms of magnitude and variation with respect to the HAWT position. Furthermore, The HIW-TUR code accurately identified the magnitude …

Value Added Products From Nonconventional Agricultural Biomass Waste Through Thermochemical Transformation, Nicolas A. Sarmiento

Electronic Thesis and Dissertation Repository

The alteration of temperature patterns around the world has become noticeable in the recent decade. Sea level rise, wildfires, and high temperatures have made people realize that climate change is affecting humans more tangibly than ever. Therefore, the United Nations have pushed to make policies to mitigate this problematic situation. This research investigated the production of biochar from agricultural waste through pyrolysis for fighting climate change and adding value to waste. Experiments in a laboratory scale reactor were conducted to obtain yields of pyrolytic products. Then, analysis of products provided data for characterization and the LCA of the tomato plant …

Wind-Borne Debris Resistance Of Façades: Identification Of Alternative Impact Test Requirements, Angela Mejorin

Electronic Thesis and Dissertation Repository

Climate change effects are causing a steady increase of previous records both in terms of monetary losses and in fatality occurrence due to severe storms. The frequency and intensity of disaster events are increasing worldwide and areas that were excluded from these extreme weather scenarios in the past, are now looking for solutions to increase the urban resilience. Among others, extreme winds are endangering the built environment, often leading to the breakage of the primary barrier to protect people and property: the building envelope. On May 22nd, 2011, the Joplin tornado killed 161 people, and 14 of those were receiving …

Effects Of Climate Change On The Probability Of Urban Tree Failures From Wind Gusts, Samuel J. Woolsey

Electronic Thesis and Dissertation Repository

Trees grown in urban environments provide environmental, economic and psychological benefits to their surrounding communities. However, urban trees also pose significant risks since damaged trees can cause serious harm to people, housing, and infrastructure by falling on sidewalks, roads, houses or power lines. To better understand the risk posed to trees by wind, models have been developed that estimates the required wind speed needed to damage a tree or group of trees, and the likelihood that such a wind speed is met or exceeded annually. The importance of such models is rising each year as the associated risk grows as …

Spatiotemporal Changes Of Lagged Compound Dry And Wet Spells In The Northwest North America Under Climate Change, Reza Rezvani

Electronic Thesis and Dissertation Repository

Recently, an upsurge in the occurrence of hydroclimatic extremes and their temporal swings is observed in several regions around the world. Such transitions to the contrasting extremes such as the drought to flood in California (2016 – 17) has raised concerns about the increasing variability and rapid transitions between hydrological extremes and their associated compounding economic and environmental impacts. The intensification of the global hydrological cycle associated with climate change can further alter the drivers of such extremes and their interactions. Therefore, it is important to understand the characteristics of consecutive flood and drought events, including their spatiotemporal frequency and …

Design Of Stick-Framed Wood Roofs Under Extreme Wind Loads, Caspar Bain

Electronic Thesis and Dissertation Repository

Light-frame wood construction comprises nearly 90% of the housing industry in
Canada and the United States. The roofs of these houses can be constructed either
entirely on site or using prefabricated trusses. Assembling the roof structure on site,
otherwise known as stick-framing, is a framing technique with current code guidelines
that are based on past practice and limited consideration of wind loads. This makes
these roof structures susceptible to failure in high-speed wind events, such as tornadoes. Around 90% of all tornadoes in Canada fall in or below the EF-2 category,
making it a possible target for design of wood-frame …

An Explicit Model For Simplified Flutter Analysis Of Long-Span Bridges, Tibebu Hunegn Birhane

Electronic Thesis and Dissertation Repository

The collapse of the First Tacoma Bridge in 1940 at a wind speed of about 18m/s triggered the need to recognize aerodynamic stability as a design constraint for long-span bridges. The advancement in understanding and modeling of dynamic wind effects has played a significant role in the realization of long-span bridges with a clear span of up to 2 km. However, the need to span longer, the risk of windstorms exceeding the strongest recorded in the past, and consequently, the quest for optimized design solutions continue to evolve.

A rigorous nature of aerodynamic stability analysis techniques poses a challenge to …

The Novel Application Of Electrical Resistivity Tomography For Spatiotemporal Monitoring Of Urban Stormwater Bioretention Systems, Darren Alvarenga

Electronic Thesis and Dissertation Repository

Bioretention systems are an increasingly popular low-impact development (LID) stormwater management approach that are used to reduce the water quantity and quality impacts of urban stormwater. The study investigated the feasibility and benefits of using non-invasive time-lapse electrical resistivity tomography (ERT) to understand the infiltration and soil moisture dynamics within bioretention systems. This was achieved through monitoring two field-scale operational bioretention systems in London, Ontario, Canada. High-resolution two-dimensional time-lapse ERT surveys were first completed during synthetic and natural rain events to assess the viability of time-lapse ERT to monitor soil moisture changes during events. Following this, three-dimensional ERT surveys were …

Modelling And Simulation Of Nonstationary Non-Gaussian Wind Speed And Wind Pressure Coefficients, Minyu Xiao

Electronic Thesis and Dissertation Repository

The time series of the wind speed from hurricane and downburst events can exhibit nonstationary non-Gaussian characteristics. Moreover, the time series of the wind pressure for a stationary wind may not be Gaussian. This thesis is focused on analyzing, characterizing, and simulating nonstationary/stationary Gaussian/non-Gaussian of wind speed and wind pressure coefficients by using time-frequency transform techniques such as the S-transform (ST) and discrete orthonormal S-transform (DOST). It is shown that by removing the mean of downburst winds, the multivariate nonstationary downburst wind speed processes can be efficiently decomposed and simulated by applying ST and DOST. It was also found that …

Improved Imaging Of Dense Non-Aqueous Phase Liquids With Three-Dimensional Surface-To-Horizontal Borehole Electrical Resistivity Tomography (S2hb Ert), Maxwell L. Servos

Electronic Thesis and Dissertation Repository

Clean-up of sites polluted with dense non-aqueous phase liquids (DNAPLs) remain a highly challenging problem. Numerous technologies are available for remediating DNAPL-contaminated sites, but their performance relies on accurate characterization and monitoring of the subsurface. Electrical resistivity tomography (ERT) is a well-established and widely used geophysical method that has been used effectively for mapping subsurface features and processes of interest. ERT can gather large volumes of continuous subsurface information in a non-destructive, cost-effective, and time-efficient manner, and exhibits highly desirable characteristics for application to DNAPL sites. However, the most traditional configuration for employing ERT is from the surface, and this …

Numerical Analysis Of Internal Hydraulic Jump In Complex Topography, Dylan Macriner

Electronic Thesis and Dissertation Repository

Topographic effects on internal hydraulic jumps in stratified flow over complex geometry are studied. The simulations are motivated by flow conditions present in a channel in Hood Canal, Washington with continuous density profiles and constant inlet velocities.

Results show that mixing in the domain is typically increased by topographic variation, where isolated expansions saw an increase in mixing, but the associated velocity decrease in expansions had contrasting effects on mixing. Likewise, a contraction with an increased velocity caused more mixing, seeing geometry change and velocity acting as compounding factors. 2D results including along channel topographic variation modelled after Hood Canal's …

Flexural Behaviour Of Concrete Beams With High Strength Reinforcement, Sohaib Akbar

Electronic Thesis and Dissertation Repository

Using High Strength Reinforcement (HSR) in concrete construction allows steel volumes to be reduced, and economies to be realized. CSA Standard A23.3:19 “Design of Concrete Structures” limits the maximum yield strength for design to 500 MPa. This thesis investigates the flexural behavior of concrete beams reinforced with HSR to assess whether current code provisions are appropriate. Curvature ductility ratios are calculated for cross-sections with varying concrete compressive strengths, and reinforcement types and quantities. The effects of utilizing HSR on extreme fibre concrete compressive strains at Ultimate Limit State (ULS), moment redistribution at ULS, and deflections at Serviceability Limit States, are …

Simulation Of Non-Homogeneous Wind Processes, Comparison Between Numerical And Experimental Model Of A Bridge, Héctor Hernández Landero

Electronic Thesis and Dissertation Repository

The scaled aerodynamic model of a bridge is often tested in the boundary layer wind tunnel laboratory (BLWTL). In this study a numerical model of the Baluarte Bridge subjected to wind loading is investigated. The scaled full bridge aerodynamic model was previously studied at the University of Western Ontario, Canada. For the numerical model a finite element model (FEM) is implemented, and the characterization of the buffeting forces are considered on the frequency and time domain. In the former case, the so-called pseudo excitation method is used to characterize the wind load, while in the latter the spectral representation method …

Compound Flooding Analysis Over The Canadian Coastal Regions, Farshad Jalili Pirani

Electronic Thesis and Dissertation Repository

The communities settling in the Canadian coastal regions are threatened by multiple flood-generating mechanisms including riverine, pluvial, and sea level forces. Reliable design flood estimation and risk assessment in these regions demand characterization of the interrelationships between different drivers as well as the corresponding compounding effects. In this study, as our first step, we assess the compound flood risks across Canada’s coasts considering eight bivariate flooding scenarios acquired from four flooding drivers including total water level, streamflow, precipitation and the skew surge at 41 sites located at three main regions of the Pacific, the Great Lakes (GL) and the Atlantic. …

Performance And Ultimate Limit State Of Large-Span Soil-Steel Structures, Kareem Embaby

Electronic Thesis and Dissertation Repository

This thesis investigates the structural behavior and soil-structure interaction mechanism of large-span soil-steel structures utilizing steel plates with the deepest corrugation profile, 500 mm X 237 mm. The world’s largest-span soil-steel bridge, with a span of 32.40 m, was constructed using 12 mm thick steel plates with the deepest corrugation profile and was instrumented extensively to monitor the displacements and straining actions of the steel structure. Lateral reinforcement steel mesh was attached to the steel structure and the ends of the structure were strengthened by circumferential reinforced concrete collars. Three-dimensional (3D) nonlinear finite element (FE) model was conducted and validated …

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 …

Assessment Of Geo-Mechanical Properties Of Lunar Simulants, Devansh Joshi

Electronic Thesis and Dissertation Repository

Abstract

Sophisticated manned and unmanned lunar missions are being developed by international collaborations of the USA, Canada, EU, India, China, Japan etc. for a long-term human presence on the moon. These lunar missions require prototype testing of rovers and other hardware on the earth to successfully interact with the lunar surface. This laboratory testing requires various simulant (terrestrial soil mimicking one or more lunar regolith characteristics) testbeds. Actual lunar soil is too pristine and scarce to be used for destructive testing. Hence, simulants have been developed by research institutions, space research organizations, or commercial manufacturers to cater to a wide …

Performance Of Fouled Railroad Superstructure Subjected To Traversing Heavy Haul Trains, Majid Kh Touqan

Electronic Thesis and Dissertation Repository

Railway transportation offers capacity, efficiency, and safety to serve the needs of modern societies for moving freight and people. Therefore, the sustainability and safety of railroad infrastructure are of paramount importance for securing transportation needs. Freight train passby loads increase the surface deformation of railroad substructure due to cumulative plastic strains, which lead to surface deviation of the railroad tracks. Correspondingly, railroad maintenance is necessary to sustain track geometry alignment and to prevent deterioration of the sub-structure over time, which can increase operating costs significantly. Therefore, this thesis evaluates the performance of fouled railroad superstructure through laboratory testing of fouled …

Evaluation Of Fresh Groundwater Resources And Nitrogen Discharge To The Coastal Lagoon Of An Atoll Island, James D. Gale

Electronic Thesis and Dissertation Repository

Atoll island communities face socio-economic challenges together with environmental pressures imposed by climate change that are causing increased water quality degradation. Wastewater from domestic septic systems is released into the subsurface on Fongafale Islet, Tuvalu. It is unclear if this is contributing to high nitrogen (N) concentrations and eutrophication of the adjacent coastal lagoon. In this study, a variable-density groundwater flow and conservative contaminant transport model was developed in SEAWAT-2005 to simulate the salinity distribution and N transport through the Fongafale Islet aquifer. Model simulations evaluated the influence of tides, variable (interannual) recharge patterns, wastewater loading rates and wastewater source …