Digital Commons Network^™

Biodegradability Of Cellulose And Its Impact On Oxygen Transfer Efficiency And Biological Nutrients Removal, Ahmed Shawki Ahmed

Electronic Thesis and Dissertation Repository

Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverable. For the first time, comprehensive mapping and tracking the fate of cellulose across various unit processes at full-scale in two water resource recovery facilities located in North America and Europe was undertaken. The influent cellulose content accounted for approximately one-third of the total suspended solids (TSS). More than 80% of the raw wastewater cellulose was captured in primary treatment. The high cellulose content of the primary sludge accounting for 17%-35% of the TSS facilitates cellulose recovery. Cellulose biodegradation efficiency varied between 70%-90% of the primary effluent, …

Reliability-Based Calibration Of Design Wind Load, Snow Load And Companion Load Factors Considering Climate Change Effect, Qian Tang

Electronic Thesis and Dissertation Repository

Wind load and snow load are two of the environmental loads that need to be considered for structural design. This study compared the statistical characteristics of the annual maximum thunderstorm and non-thunderstorm winds based on the updated wind speed dataset and carried out the extreme value analysis for wind load by treating the synoptic and thunderstorm winds separately. The results indicated that for southern Ontario and the southern part of the Prairies, the extreme winds could be dominated by thunderstorm winds. The consideration of both thunderstorm winds and synoptic winds separately to recommend the reference wind velocity pressure for the …

Finite Element Analyses And Random Field Modeling Of Naturally Corroded Underground Energy Pipelines, Ji Bao

Electronic Thesis and Dissertation Repository

Metal-loss corrosion is one of the major threats to the integrity of oil and natural gas pipelines. The Fitness-For-Service (FFS) assessment is commonly carried out to demonstrate the integrity of the corroded pipelines. The naturally occurring corrosions on the external surfaces are irregularly shaped three-dimensional features. Due to the geometric complexity of the natural corrosion features, the research of FFS assessment in the previous studies always employed the pipe segments containing artificially induced corrosion features. However, since artificial features are in general regular-shaped, e.g. cubic or semi-ellipsoidal, they do not capture geometric characteristics of naturally occurring corrosions. The thesis develops …

Machine Learning Prediction Of Shear Capacity Of Steel Fiber Reinforced Concrete, Wassim Ben Chaabene

Electronic Thesis and Dissertation Repository

The use of steel fibers for concrete reinforcement has been growing in recent years owing to the improved shear strength and post-cracking toughness imparted by fiber inclusion. Yet, there is still lack of design provisions for steel fiber-reinforced concrete (SFRC) in building codes. This is mainly due to the complex shear transfer mechanism in SFRC. Existing empirical equations for SFRC shear strength have been developed with relatively limited data examples, making their accuracy restricted to specific ranges. To overcome this drawback, the present study suggests novel machine learning models based on artificial neural network (ANN) and genetic programming (GP) to …

Joint Wind And Ice Effects On Transmission Lines In Mountainous Terrain, Daniel Davalos Arriaga

Electronic Thesis and Dissertation Repository

Atmospheric icing on mountainous terrain can produce catastrophic damages to transmission lines when incoming particles impinge and accrete on the cable surface of the system. The first challenge in wind-ice loading is determining joint statistics of wind and ice accretion on transmission lines. This study analyzes the weather characteristics for a specific site of study using 15 years of historical data to use as inputs for ice accretion modeling. The joint wind and ice hazard is characterized by simulating 500 years of icing events from the fitted probability distributions of ice accretion and wind on ice velocities. The second challenge …

Effect Of The C-Source And Cod/N On Nitrite And Partial Nitrate Denitrification, Ahmed Fathy Elyas Badia

Electronic Thesis and Dissertation Repository

The main objectives of this study were: (i) to investigate dynamic specific denitrification rates (SDNR) from nitrite at various chemical oxygen demand (COD) / nitrogen (N) ratios using municipal wastewater (MWW) and acetate, and to study the kinetic parameters, (ii) to investigate the dynamic specific denitrification rates (SDNRs) from nitrite at various COD/N ratios in a system that uses methanol as a complementary carbon source, and studying the effect in case if nitrate replaced nitrite, and (iii) to investigate and compare between the nitrite shunt and N-PDN-anammox technologies through studying the dynamic specific denitrification rates (SDNRs) from nitrate and nitrite …

Machine Learning Prediction Of Mechanical And Durability Properties Of Recycled Aggregates Concrete, Itzel Rosalia Nunez Vargas

Electronic Thesis and Dissertation Repository

Whilst recycled aggregate (RA) can alleviate the environmental footprint of concrete production and the landfilling of colossal amounts of demolition waste, there need for robust predictive tools for its effects on mechanical and durability properties. In this thesis, state-of-the-art machine learning (ML) models were deployed to predict properties of recycled aggregate concrete (RAC). A systematic review was performed to analyze pertinent ML techniques previously applied in the concrete technology field. Accordingly, three different ML methods were selected to determine the compressive strength of RAC and perform mixture proportioning optimization. Furthermore, a gradient boosting regression tree was used to study the …

Biomechanics Of Trees Under Extreme Wind Loading Events, Mojtaba Dargahi

Electronic Thesis and Dissertation Repository

For urban planners, arborists and foresters, understanding tree stability under self-weight and applied loads from wind and snow is important when developing management strategies to reduce the risk of damage from these abiotic agents. Current predictive approaches are generally empirical and based on a posteriori surveys of failures. A more rigorous engineering approach to understanding response phenomenon in trees subjected to extreme winds has been attempted herein. The size of trees and their architecture (shape and structure) greatly influence their mechanical stability under dynamic loading. Considering trees as porous media, wind loads on them are affected by their resistance to …

Ultimate And Serviceability Limit States Of Large Shallow Foundations Under Combined Loading, Pengpeng He

Electronic Thesis and Dissertation Repository

Estimation of the bearing capacity and deformations of large shallow foundations under combined loadings can be of great significance. Some geotechnical design guidelines recommend the failure load envelope method for ultimate limit state analysis. Since many investigations of this method focus primarily on undrained failure envelopes using unlimited-tension interfaces, zero-tension interfaces have not been well investigated. In addition, less work is available on drained failure envelopes. For serviceability limit states, the majority of approaches used are based on uncoupled, isotropic assumptions. Further work needs to be done on more appropriate elastic solutions for combined loadings.

General VHMT failure envelopes for …

Structural Performance Of Ordinary And Laminated Glass During Fire Exposure, Amer Sabsabi

Electronic Thesis and Dissertation Repository

Façade and glazing elements constitute the skin of buildings. They are the interface between the inside and outside environment. Glass has low fire resistance and can quickly break during fire events. This creates new vents, which increase the oxygen supply and promote the flashover phenomenon. Existing methods for evaluating the structural fire safety of glass require expensive experimental tests or extensive knowledge of finite element (FE) modeling. This research provides simplified, rational, and reliable methods to assess the behavior of ordinary and laminated glass panels during fire exposure. The proposed methods provide the means to determine the glass temperature and …

Material Evaluation And Structural Monitoring Of Early-Age Masonry Structures, Kyle Dunphy

Electronic Thesis and Dissertation Repository

During the initial construction period, “early-age” masonry walls are susceptible to lateral loads induced by wind or earthquake, which may result in damages or catastrophic failures. To mitigate such consequences at construction sites, temporary bracings are adopted to provide lateral support to masonry walls until they are matured enough to serve as the inherent lateral system of the structure. However, current temporary bracing guidelines provide oversimplified design due to the lack of available information on the material properties of early-age masonry. Moreover, there are no existing techniques for monitoring masonry walls to detect cracks due to construction activities. …

Seismic Hazard Assessment For Mainland China Based On Spatially Smoothed Seismicity And Projected Sets Of Ground Motion Models, Chao Feng

Electronic Thesis and Dissertation Repository

The latest version of the Chinese seismic hazard map (CSHM) (i.e., fifth-generation CSHM) was developed based on the delineated seismic source model, which is defined based on geological and seismological information but also with some subjectivities. The results of the CSHM were presented in terms of peak ground acceleration (PGA) and peak ground velocity. No maps for spectral acceleration (SA) are given. This is partly due to the ground motion models (GMMs) to predict SA for mainland China are unavailable. The unavailability of the GMMs for SA results in the lack of uniform hazard spectra (UHS) that is important for …

Classification, Localization, And Quantification Of Structural Damage In Concrete Structures Using Convolutional Neural Networks, Majdi Flah

Electronic Thesis and Dissertation Repository

Applications of Machine Learning (ML) algorithms in Structural Health Monitoring (SHM) have recently become of great interest owing to their superior ability to detect damage in engineering structures. ML algorithms used in this domain are classified into two major subfields: vibration-based and image-based SHM. Traditional condition survey techniques based on visual inspection have been the most widely used for monitoring concrete structures in service. Inspectors visually evaluate defects based on experience and engineering judgment. However, this process is subjective, time-consuming, and hampered by difficult access to numerous parts of complex structures. Accordingly, the present study proposes a nearly automated inspection …

Tornado Occurrence Modelling And Equivalent Tornado Design Wind Profile For Canada, Qian Huang

Electronic Thesis and Dissertation Repository

The tornadoes can be devastating to structures and infrastructure systems. They can cause fatalities and economic losses. In this thesis, the tornado hazard for Canada is systematically assessed. The use of three spatial point processes (i.e., Poisson, zero-inflated Poisson, and negative binomial models) are first investigated in a hierarchical structure to predict the tornado occurrence rate by considering the annual cloud-to-ground lightning flash density and annual thunderstorm days as covariates. An existing historical tornado catalogue with reported tornado events up to 2009 is considered and the population bias effect in estimating the tornado occurrence rate is included. Both the Bayesian …

Evaluation And Bias Correction Of Remotely Sensed Precipitation Products Across Canada, Saber Moazamigoodarzi

Electronic Thesis and Dissertation Repository

Reliable estimation of precipitation, as the most important variable in hydrological modelling, is crucial for water resources management. Rain gauges that provide precipitation measurements at point scale have inherent limitations and difficulties in remote regions and complex terrains due to accessibility, gauge undercatch, among others. Alternatively, satellite and radar precipitation data can estimate precipitation at high spatial and temporal resolution by utilizing several types of space and ground-borne sensors. However, due to the indirect estimates of precipitation by remotely sensed products, their measurements are subject to systematic biases and are required to be evaluated and bias adjusted before using at …

Biological Nutrient Removal: Minimizing Carbon And Oxygen Requirements, Masuduz Zaman

Electronic Thesis and Dissertation Repository

With increasing focus on the carbon footprint of wastewater treatment and rapidly emerging paradigm shift towards resource recovery, energy consumption minimization and utilization of readily available organics for biological nutrient removal in municipal wastewater treatment plants is eliciting significant interest. The objective of this PhD work is to investigate non-traditional approach to minimize carbon and energy demand for biological nutrient removal

The feasibility of using thermal alkaline treated municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal was investigated. Two sequencing batch reactors (SBRs) were operated with synthetic volatile fatty acids (acetic acid and propionic acid) and …

New Model And Simulation Algorithm Of Nonstationary Non-Gaussian Ground Motions Based On S-Transform, Xizhong Cui

Electronic Thesis and Dissertation Repository

The seismic ground motions are nonstationary stochastic processes and vary from site to site. The time histories of synthetic ground motions are used for nonlinear inelastic structural dynamic analysis since the historical records are limit or unavailable for a particular scenario seismic event. This is especially the case for structures with multiple supports. The characteristics of the nonstationary stochastic ground motions depend on the earthquake magnitude, fault mechanism, source-to-site distance, and local site conditions. The characteristics could be represented by time-frequency (dependent) power spectral density (TFPSD) and coherence functions. The assessment of such power spectral density and coherence functions are …

Experimental And Numerical Study On Three-Edge Bearing Test For Reinforced Concrete Pipe, Abdul-Aziz Younis

Electronic Thesis and Dissertation Repository

Reinforced Concrete Pipe (RCP) is widely used in storm and wastewater management owing to its resiliency and reliability. The century old Three-Edge Bearing Test (TEBT) is currently used to classify RCP strength. The test relies on the skill and experience of the operator for capturing the occurrence of a 0.3-mm-wide crack using a leaf-gauge, which induces subjectivity and error. Studies have also indicated the TEBT crack bears little structural significance.

This thesis aims at improving the TEBT by replacing the arbitrary crack-width with rational capacity-driven criteria. A wide range of full-scale RCP were instrumented and subjected to the modified TEBT …

Experimental And Numerical Study Of Precast Concrete Pipe With Single Elliptical Steel Cage Reinforcement, Abdullah Samir Ramadan

Electronic Thesis and Dissertation Repository

Reinforced concrete pipe (RCP) with single elliptical (SE) reinforcement offers cost savings and is permitted by Canadian and American standards. Yet, its use has not yet gained momentum primarily due to limited knowledge of its structural performance. This study explores the structural behaviour of full-scale 1050 mm and 1200 mm diameter RCP reinforced with SE cold drawn steel wire cage under the Three-Edge Bearing Test. Results indicate that RCP with SE reinforcement designed per current standards did not meet the specified 0.3-mm crack and ultimate load capacity. Hence, pertinent provisions in CSA A257.2 and ASTM C76 for RCP need to …

Internal Pressure Modelling For Low-Rise Buildings In Tornadic Winds, Aaron L. Jaffe

Electronic Thesis and Dissertation Repository

Internal pressures play a large role in the failure of wood-frame houses as the loss of the entire roof section becomes much more likely once the envelope of the building has been breached. Many studies have used internal pressure modelling to simulate internal pressures in structures from atmospheric boundary layer (ABL) winds, however, relatively little work has been done on this subject using tornadic winds. The objective of this study is to explore internal pressure modelling issues for tornadoes. The first part of the study uses a computational internal pressure model to simulate tornadic internal pressures of a low-rise structure; …

Identification Of Aerodynamic Damping For Flexible Structures Using Wind-Induced Response, Shea Laventure

Electronic Thesis and Dissertation Repository

Damping estimation is a critical task to perform during the design of slender structures, or for existing structures. This is to ensure the response of the structure is within allowable limits and to determine if additional damping is necessary from auxiliary devices. If a slender structure is experiencing wind loading, a phenomenon known as aerodynamic damping arises, which has the potential to reduce the damping of the structure. The most efficient method to estimate aerodynamic damping is to use a system identification technique, which requires only the input forces and output response of the structure. This thesis describes how to …

Lateral Load Analysis Of Multi-Storey Light-Frame Wood Buildings Through Detailed And Simplified Numerical Approaches, Chu Peng

Electronic Thesis and Dissertation Repository

Increasing global demand for a sustainable society is driving the development of multi-storey light-frame wood structures (LFWSs). A high-resolution finite element modelling (FEM) procedure for three-dimensional multi-storey LFWS buildings is developed. This tremendous effort is carried out to have a benchmark model that can be used for the validation of simpler models and for the assessment of the structural performance considering system effects. High-resolution FEM of all components of a building is not practical. A simplified FEM procedure is developed based on equal work principle. Verification of the accuracy of the high-resolution model is undertaken by comparing the natural frequencies …

Quantification Of Septic System Contribution To Nutrient Loads In Surface Waters, Archana Tamang

Electronic Thesis and Dissertation Repository

Freshwater systems worldwide are threatened by excessive nutrient (nitrogen and phosphorus) loading. This study evaluated the contribution of septic systems to stream nutrient loads in nine subwatersheds. Stream sampling was conducted during low and high discharge conditions, with samples analyzed for total phosphorus (TP), soluble reactive phosphorus (SRP), nitrate (NO₃-N), and acesulfame (ACE; wastewater tracer). Higher septic effluent reached the subwatershed outlets during high discharge conditions. Subwatersheds with newer households had a lower percentage of septic effluent reaching the stream compared with subwatersheds with older households. Seasonal and event-based ACE concentration-discharge relationships revealed that the hydrological pathways delivering …

Smouldering Combustion Treatment Of Soils And Granular Activated Carbon Contaminated With Per- And Polyfluoroalkyl Substances, Alexandra L. Duchesne

Electronic Thesis and Dissertation Repository

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants, ubiquitous in the environment, and are challenging to remediate. Self-sustaining Treatment for Active Remediation (STAR) destroys organic contaminants embedded in porous media using smouldering combustion. Self-sustaining smouldering conditions allow the reaction to propagate through the contaminated media without external energy. This study explored STAR as a remediation option for PFAS-impacted granular activated carbon (GAC) and PFAS-contaminated soil. Three smouldering mixtures were used (i) PFAS-spiked GAC and sand, (ii) PFAS-spiked soil and GAC, (iii) PFAS-contaminated field site soil and GAC. Smouldering temperatures were greater than 900˚C, destroying the GAC. Post-treatment PFAS concentrations of …

Advanced Hardware And Software Approach To Seismic Site Response Investigations, Aleksandar Dimitrov Mihaylov

Electronic Thesis and Dissertation Repository

Vibration measurement is an essential aspect of modern geotechnical engineering. It is particularly vital task for measuring the dynamic soil parameters, estimating seismic hazards and evaluating influence of industrial, traffic and construction vibrations on the surrounding buildings, structures and their elements. Meanwhile, commercial exploration seismic stations and data acquisition systems require significant professional knowledge and training in geophysics or vibration measurement, as well as practical skills and experience in adjusting data acquisition parameters. Furthermore, available seismological investigation and vibrometry sensors are not universally suitable for field applications in geophysical studies, soil-structure interaction investigations or structural vibrations. The frequency range suitable …

Progressive Failure Of Transmission Line Towers Under Different Tornado Wind Fields, Wesam Abdelhamid Mohamed

Electronic Thesis and Dissertation Repository

High-intensity wind events (downbursts and tornadoes) cause the majority of weather-related transmission line (TL) failures, which detrimentally affect society. This study investigates the progressive failures of single TL towers and TL systems under different F2 tornadoes. Different tornado wind fields are incorporated in a fluid-structure software developed at Western University. Progressive failure analysis is then conducted for four towers under the most critical tornado configurations identified from extensive parametric studies. Moreover, the cost associated with designing TLs to sustain F2 tornadoes is investigated by strengthening the TL towers. Finally, the progressive failure within self-supported TL systems under different tornadoes, and …

System Reliability Analysis Of Defected Pile Group Foundations, Abdalla E. Adlan Alhashmi

Electronic Thesis and Dissertation Repository

Deep foundations design suffers some degrees of uncertainties. This thesis studies the behavior of defected pile group foundations installed in sand and calibrates the resistance factor of pile group foundation, utilizing a rational based system reliability analysis. This was achieved by conducting a comprehensive numerical parametric investigation using the computer program ABAQUS/Standard. The result of the parametric study showed that the presence of a defected pile in a pile group foundation causes lateral deflection of the pile cap and hence induces bending moment at the adjacent piles which affects the load distribution mechanism of the system. It was also found …

Effects Of Drinking Water Treatment Processes On Removal Of Algal Matter And Subsequent Water Quality, Ziming Zhao

Electronic Thesis and Dissertation Repository

Seasonal algal blooms in drinking water sources have increased significantly over the recent past as a result of increased temperature and nutrient loading in surface water due to agricultural and surface runoff. More than 95% of algal cells can be removed by coagulation and flocculation processes. However, algal organic matter (AOM) is not removed well during coagulation, thus causes several operational challenges in drinking water treatment. This research was conducted to investigate the effectiveness of coagulation, granular activated carbon adsorption, and filtration processes on AOM removal and to evaluate disinfection by-products formation potential with/without UV irradiation.

Initially, coagulation performance for …

The Influence Of Porous Media Heterogeneity On Smouldering Remediation, Jiahao Wang

Electronic Thesis and Dissertation Repository

Smouldering remediation is a promising technique for destroying organic contaminants in soil. Forced airflow is vital to supporting the smouldering reaction and to propagate it through the contaminated zone. This research focuses on investigating the effects of permeability heterogeneity on smouldering. A series of unique column experiments, combined with numerical model simulations, were conducted. The results suggest that smouldering can successfully propagate through layers in series despite more than a 1000:1 permeability contrast. However, extinction can occur in the finer layer when smouldering propagates through layers in parallel with a permeability ratio above 3:1. Extinction may occur due to insufficient …

Seismic Performance Of Superelastic Shape Memory Alloy Reinforced Concrete Shear Wall Systems, Emad A. Abraik

Electronic Thesis and Dissertation Repository

A major sustainability issue for reinforced concrete (RC) structures is the residual deformations caused by the yielding of the steel bars during extreme seismic events. Numerous efforts have been made to develop self-centering structures, which minimize these deformations and the associated seismic damage. Superelastic shape memory alloys (SE-SMA) can be utilized in concrete elements to achieve such behaviour. This thesis focuses on the use of SE-SMA bars in RC walls.

First, the thesis starts by conducting a fragility analysis to assess the seismic performance and vulnerability of ten and twenty-story SE-SMA RC walls. SE-SMA bars are used within the plastic …