Digital Commons Network^™

Anthropogenic Effects On Tidal Distortion In A Tidal River, Matthew D. Fischer

Electronic Theses and Dissertations

Tidal rivers are landward portions of estuarine systems constituting the union between coastal, tidally controlled settings and rivers, where fluvial processes dominate. In these reaches, river discharge (mean flow) and tides are the two most important mechanisms in controlling geophysical flows. The processes governing water levels and current amplitudes in tidal rivers are highly nonlinear and modulated by external forcings- thus requiring sophisticated techniques for accurate prediction and forecasting. Physical oceanographers and estuarine physicists tend to limit their study area to the maximum extent of the horizontal tide (salinity intrusion), not the most landward point influenced by tidal water levels. …

Modeling The Impact Of The Covid-19 Pandemic On Speeding At Rural Roadway Facilities In Maine Using Short-Term Speed And Traffic Count Data., Amirhossein Shahlaeegilan

Electronic Theses and Dissertations

The COVID-19 pandemic caused a significant change in traffic operations and safety. For instance, various U.S. states reported an increase in the rate of fatal and severe injury crashes over this duration. In April and May 2020, the comprehensive stay-at-home orders were issued across the country, including in Maine. These orders resulted in drastic reductions in traffic volume,switching working policies of noticeable number of corporations and educational administrations like universities to the remote working, closure of many organizations during the lockdown period, and people avoidance to public places to suppress the possible exposure to the virus were among the most …

Role Of Microplastics On The Release And Adsorption Of Organic Compounds In Natural Waters, Ashton Collins

Electronic Theses and Dissertations

Microplastics in the aquatic system are among the many inevitable consequences of plastic pollution, which has cascading environmental and public health impacts. The implications lead to the production of leachate comprised of dissolved organic matter (DOM) and increasing adsorption potential of organic compounds (OCs) onto the microplastic surfaces. In this study, the adsorption potential of organic pollutants and the formation of microplastic leachate from ultraviolet (UV) light were explored. The adsorption potential was created through a summarization and critical review of the literature on the adsorption of synthetic OCs by microplastics in aqueous environments since their emergence in 2008. A …

Wave And Tide Driven Nearshore Processes: Implications For Tidal Asymmetry And Coastal Protection, Samuel Rickerich

Electronic Theses and Dissertations

The dynamics of the coastal ocean are driven by wind, buoyancy, tidal, and wave processes. In the context of the variability of the coastal ocean driven wave action, storm surge, and sea level rise, understanding interactions between physical processes and means to mitigate their effects is necessary. It is the goal of this study to extend the understanding of (i) wave and tidal hydrodynamics in coastal areas and (ii) explore adaptable coastal defense strategies for these environments. These goals are addressed through process-oriented hydrodynamic-wave simulations. As tides enter the coastal ocean, nonlinear interactions from bathymetry, friction, and variations in tidal …

Nutrient Removal From Recirculating Aquaculture System Water, Eliza M. Costigan

Electronic Theses and Dissertations

Recirculating aquaculture systems (RAS), where only approximately 10% of the total system water is exchanged per day, have grown in popularity in recent years due to their potential to provide a high-quality protein source in a contained environment. With increased production comes the need for RAS water treatment to mitigate recirculation and discharge of nutrients produced by fish; mainly phosphorus and nitrogen. When discharged, nutrients can contribute to eutrophication in surrounding water bodies, harming the fish and other aquatic life. Therefore, RAS effluent should be treated before discharge. One method of phosphorus removal is adsorption, a surface phenomenon that is …

Generalizing The Negative Binomial-Lindley Model For Accounting Subpopulation Heterogeneity In Crash Data Analysis, A S M Mohaiminul Islam

Electronic Theses and Dissertations

Crash data are often highly dispersed; it may also include a large amount of zero observations or have a long tail. The traditional Negative Binomial (NB) model cannot model these data properly. To overcome this issue, the Negative Binomial-Lindley (NB-L) model has been proposed as an alternative to the NB to analyze data with these characteristics. Research studies have shown that the NB-L model provides a superior performance compared to the NB when data include numerous zero observations or have a long tail. In addition, crash data are often collected from sites with different spatial or temporal characteristics. Therefore, it …

Optimization Of A Lightweight Floating Offshore Wind Turbine With Water-Ballast Motion Mitigation Technology, William Ramsay

Electronic Theses and Dissertations

Floating offshore wind turbines are a promising technology to address energy needs utilizing wind resources offshore. The current state of the art is based on heavy, expensive platforms to survive the ocean environment. Typical design techniques do not involve optimization because of the computationally expensive time-domain solvers used to model motions and loads in the ocean environment. However, this project uses an efficient frequency domain solver with a genetic algorithm to rapidly optimize the design of a novel floating wind turbine concept. The concept utilizes liquid ballast mass to mitigate motions on a lightweight post-tensioned concrete platform, with a target …

Optimal Scheduling Of Connected And Autonomous Vehicles At A Reservation-Based Intersection., Muting Ma

Electronic Theses and Dissertations

Reservation-based intersection control has been evaluated with better performance over traditional signal controls in terms of intersection safety, efficiency, and emission. Controlling connected and autonomous vehicles (CAVs) at a reservation-based intersection in terms of improving intersection efficiency is performed via two factors: trajectory (speed profile) and arrival time of CAVs at the intersection. In an early stage of the reservation-based intersection control, an intersection controller at the intersection may fail to find a feasible solution for both the trajectory and arrival time for a CAV at a certain planning horizon. Leveraging a deeper understanding of the control problem, reservation-based intersection …

Development Of Ultra High Performance Composite Impact Panels Using Emaa, Jeffrey Hollstein

Electronic Theses and Dissertations

UHPC with the addition of fibers is recognized for its increased impact resistance compared to typical strength concrete. To further increase the resilience, recent studies have been conducted to reinforce the UHPC with CFRTP on the front and rear face to create sandwich panels. These studies used PETg/E-glass CFRTP bonded to the UHPC using EMAA (Surlyn) in a stamp thermoforming process. Impact tests conducted on these panels have shown that delamination has been the initial and detrimental failure to the sandwich composite. Increasing the composites resistance to debonding will increase the impact energy required to debond the composite. In this …

On The Application Of Dynamical Measures Of Hydrologic Response To Prediction And Similarity Assessment In Watersheds, Prashanta Bajracharya

Electronic Theses and Dissertations

The Prediction in Ungauged Basins (PUB) initiative set out to improve the understanding of hydrological processes with an aim of improving hydrologic models for application in ungauged basins. With a majority of basins around the world essentially ungauged, this suggests the need to shift from calibration-based models that rely on observed streamflow data to models based on process understanding. This is especially important in natural infrastructure planning projects such as investments in the conservation of wetlands across the watershed, where the lack of streamflow data hinders the quantification of their benefits (such as flood attenuation), resulting in a difficulty in …

Road Salt Use Analysis In The Context Of Changing Winter Weather Conditions, Dikshya Parajuli

Electronic Theses and Dissertations

The research is inspired by the past and current patterns of road salt use, changing weather patterns, and management strategies in Maine. The historical road salt application has led to long-term impacts on the environment pressing the need for strategic use of road salt. Winter Severity Indices (WSIs) find their application in the field by aiding in interpreting weather forecasts and planning for strategic salt application. This study uses existing indices: Accumulated Winter Season Severity Index (AWSSI), Strategic Highway Research Program (SHRP) index, Illinois Salt days index, and Accumulated Freezing Degree Days to quantify long-term changes in winter weather conditions. …

Mixing Processes In Tidally Pulsed River Plumes: Mechanisms, Significance, And Variability, Preston Spicer

Electronic Theses and Dissertations

River plumes form at the river-ocean interface when fresh, buoyant river water merges with salty, dense ocean water and can significantly modify coastal water properties and circulation. It is important to understand how plumes physically mix into the ocean to inform predictive modeling of river-borne tracers to coastal seas. In tidally energetic regions such as New England, river plumes can form and evolve with each new tide and are referred to as “tidally pulsed”. In this dissertation, we explore the numerous mechanisms which can contribute to mixing tidally pulsed plumes (i.e., frontal, stratified shear [interfacial], and bottom-generated tidal mixing) their …

Statistical Analysis Of Frequency And Severity Of Lane Departure Crashes In Maine, Alainie A. Sawtelle

Electronic Theses and Dissertations

Lane departure crashes account for approximately 34% of all roadway crashes, and over 70% of all roadway fatalities in Maine. Despite an 18% decrease in average daily traffic volume during the half of the year with colder weather, the months of November to April comprise over 64% of the yearly lane departure crashes. The majority of roadways and roadway crashes in Maine are in rural regions. Moreover, Maine has aging infrastructure, houses the oldest population in the United States, has diverse terrain and land use, and experiences several extreme weather events. The combination of these factors impacts the frequency and …

Joining Methods For Continuous Fiber Reinforced Thermoplastic Composites In Structural Applications, Andrew Moran

Electronic Theses and Dissertations

Continuous fiber reinforced thermoplastic (CFRTP) composites have been proposed as an alternative to metals in structural applications. CFRTP composites can be used to create structures that are lighter weight, have better resistance to environmental factors, and have the potential to be recycled. However, one of the main challenges to CFRTP composites is connections between structural members. The goal of this thesis is to investigate the feasibility of joining CFRTP composites to both similar and dissimilar materials through literature review, coupon testing, design of a structural joint, and a small scale laboratory prototype of the joint. To achieve this goal the …

Non-Destructive Evaluation Of Concrete Using Electrical Resistivity And Ultrasonic Wave Propagation, Justin Harris

Electronic Theses and Dissertations

With the intent to investigate the relationship between concrete physical properties and non-destructive evaluation techniques (NDE), several experiments were performed. Specimens were made at varying geometries using a range of different concrete mixes under several different curing conditions. These specimens were subjected to a combination of electrical resistivity and ultrasonic wave propagation measurements. One part of this study investigated determining the orientation of steel fibers using electrical resistivity. This resulted in the fabrication of a four-probe square device with the potential capabilities of determining fiber orientation. The other part of this research applied ultrasonic wave propagation via through-transmission along with …

Development Of Thermoplastic Composite External Reinforcing Of Concrete Decking System, Jackman A. Mickiewicz

Electronic Theses and Dissertations

The use of reinforced concrete is very common in the construction of a wide variety of structures. In buildings it is used for floors, beams, columns, and walls. It can also be used in infrastructure as parts of bridges, dams, pavements, etc. Typically, concrete is reinforced with steel, primarily rebar, to carry tensile stresses.

Like every other industry, construction is always looking at ways to advance its technology. The work outlined in this thesis looks to assist in that goal, primarily by looking at options for using a different material than the traditional steel reinforcements to create a reinforced concrete …

Utilizing Shockwave Theory And Deep Learning To Estimate Intersection Traffic Flow And Queue Length Based On Connected Vehicle Data., Abdulmaged Algomaiah

Electronic Theses and Dissertations

The development of Connected Vehicles (CV) facilitates the use of trajectory data to estimate queue length and traffic volume at signalized intersections. The previously proposed models involved additional information that may require conducting different types of data collection. Also, most models need higher market penetration rate or more than a vehicle per cycle to provide adequate estimation. This is mainly because a significant number of the estimation models utilized only queued vehicles. However, the state of motion in non-queued vehicles, particularly slowed-down vehicles, provides much information about the traffic characteristics. There is a lack of exploiting the information from slowed-down …

Data Linkage For Crash-Injury Outcome Assessment., Aryan Hosseinzadeh

Electronic Theses and Dissertations

Introduction: Traffic crash reports lack detailed information about emergency medical service (EMS) responses, the injuries, and the associated treatments, limiting the ability of safety analysts to account for that information. Integrating data from other sources can enable a better understanding of the characteristics of serious crashes and further explain variance in injury outcomes. In this thesis, first, a heuristic approach is proposed and implemented to link crash data to EMS run data, patient care reports, and trauma registry data. Next, the method was adapted through larger datasets in a statewide linkage effort. The performance of the heuristic method was compared …

Developing Takeover Request Warning System To Improve Takeover Time And Post-Takeover Performance In Level 3 Automated Drivin, Niloy Talukder

Electronic Theses and Dissertations

The automotive industry is shifting towards partial (level 3) or fully automated vehicles. An important research question in level 3 automated driving is how quickly drivers can take over the vehicle control in response to a critical event. In this regard, this study develops an integrated takeover request (TOR) system which provides visual and auditorial TOR warning in both vehicle interface and personal portable device (e.g., tablet). The study also evaluated the effectiveness of the integrated TOR system in reducing the takeover time and improving post-takeover performance. For these purposes, 44 drivers participated in the driving simulator experiment where they …

The Role Of Pier Shape And Aspect Ratio On Local Scour With And Without Sacrificial Piles, Mohamed Kharbeche

Electronic Theses and Dissertations

The complexity of the scour process around bridge piers leads to uneconomical pier design and unnecessary costs. This is due to the current scour estimation methods, which over-predict scour depth. Several aspects of scour have not been fully considered in pier design and require further investigation, such as the pier shape and aspect ratio. Further, scour countermeasures are used to protect the pier and reduce the scour depth. The first objective of the present investigation is to study the combined effects of pier nose shape and aspect ratio on scour geometry. The second objective is to better understand the effect …

Modeling Freight Network Robustness And Criticality In Ontario, Canada, Georgiana Vani

Electronic Theses and Dissertations

This dissertation explores criticalities that arise in a freight transportation network for the multi-regional economically active province of Ontario, Canada. A significant economic contributor and generator of freight trips, Ontario relies on its transportation system for the movement of goods. A combination of network performance and economically driven measures are used to evaluate the impacts of link disruptions, identify criticalities in the network, and produce a more holistic view of freight transportation activities. The Network Robustness Index (NRI) is applied to capture the impacts of travel conditions on the network due to link disruptions. A methodology is introduced for estimating …

Development Of A Control Strategy To Reduce The Start-Up Delay For Autonomous Heavy Trucks, Saeideh Esmaeili

Electronic Theses and Dissertations

Trucks generally possess a lower level of acceleration, and the start-up delay by trucks exacerbates the signalized intersections’ performance. To mitigate the impact of start-up delay, this study proposes a vehicle-specific stop point and pre-start time for the signalized intersection, which will be referred to as advanced stop point and prior start time (ASP-PST) traffic control system. It utilizes vehicle-to-vehicle (V2V) communications between the signal controller and heavy trucks. The heavy truck starts from a faraway upstream point but before the green light starts. This study provides an analytical solution for the …

Development Of Eco-Friendly Lightweight Thermal-Efficient Composites For Wall Panels, Oluwafemi Adewoyin

Electronic Theses and Dissertations

One of the effective ways to improve the energy efficiency of buildings is the use of thermally efficient materials in the production of various building envelop elements such as wall panels. With the increasing sustainability awareness in the construction industry and the use of cementitious materials being the most used construction materials, eco-friendly materials such as expanded glass can be utilized as lightweight aggregates to produce lightweight mortars for the construction of these elements. This thesis presents the results from the evaluation of mortars designed for the production of lightweight thermal efficient wall panels using expanded glass as aggregates. The …

Sustainable Utilization Of Clay Soils As Low-Cost Binders In Construction Applications, Rushikesh R. Darange

Electronic Theses and Dissertations

Clay in its natural form is widely used as a construction material for the development of various building products and binders for earthen houses due to the rising cost of traditional building materials. The increasing demand for earthen houses has created the necessity to improve the functional properties of raw clay binders that are being commonly stabilized with Ordinary Portland Cement (OPC). An environmental concern associated with the use of OPC is the major driver to develop a clay binder by using the alkali activation technology.

In this study, clay binders were produced by using various alkali activators and incorporating …

Sustainability And Performance Improvement Of Engineered Cementitious Composites, Adeyemi Adesina

Electronic Theses and Dissertations

Engineered cementitious composites (ECCs) are special types of fibre-reinforced cementitious composites (FRCC) with higher strain capacity which can be achieved with low fibre volume as low as 2% and total elimination of coarse aggregates. Due to the outstanding performance of ECCs, they are suitable for various construction and repair applications. However, in order for ECCs to achieve their properties; a high amount of binder which is primarily composed of Portland cement (PC) is used alongside a special type of ultrafine silica sand (USS) which is different from the conventional natural fine aggregates. The production of PC is known to be …

Application Of Artificial Neural Networks To Predict Local Bridge Pier Scour, Mia Marrocco

Electronic Theses and Dissertations

Accurate equilibrium scour depth and width estimations are essential to both safe and economic designs of bridge foundations. Review of current scour estimation methods demonstrate that the empirical equations produce scour values that are overestimated, resulting in uneconomical designs. In the current investigation, artificial neural networks (ANNs) were optimized and applied to scour data under laboratory conditions, field conditions, and a combination of the two conditions. Additionally, physics-based parameters – in place of empirical parameters (e.g., shape factors) – and parameters incorporating blockage effects were introduced as input parameters to the ANNs in an attempt to improve scour predictions. Finally, …

Repairable Precast Bridge Bents For Seismic Events, Kallan Hart

Electronic Theses and Dissertations

Concrete bridge columns are designed to withstand earthquakes by undergoing large displacements. Current seismic bridge codes guarantee collapse prevention, but damage to concrete and longitudinal reinforcement often requires demolition of the structure. Repairable detailing and advanced bridge construction connections may be utilized in concrete bridge columns to allow for quick construction as well as replacement of damaged reinforcement after an earthquake. This detailing may be an attractive alternative to bridge owners to reduce construction and replacement costs as well as ensure the functionality of critical routes after an earthquake. Three repairable precast bridge columns with exposed longitudinal reinforcement were tested …

Advanced Toll Information System And Toll Lane Configuration To Reduce Collision Risk, Farnaz Zahedieh

Electronic Theses and Dissertations

This study assessed the impacts of presence and location of the toll information system on the traffic performance and safety at toll plaza on the Gordie Howe International Bridge. The toll information displays the information on toll payment methods (manual toll collection (MTC), automatic toll collection (ATC) and electronic toll collection (ETC)) for cars or heavy vehicles (HV) via variable message signs (VMS) upstream of toll booth. The study also assessed the impacts of the toll information system with different toll lane configuration for current traffic demand and different percentages of heavy vehicles (HV) to reduce the collision risk at …

Nitrate Removal During The Shoulder Months In The Occoquan Reservoir: A Comprehensive Study, Km Risaduzzaman

Electronic Theses and Dissertations

The artificial nitrate addition by the Upper Occoquan Service Authority (UOSA)’s Water Reclamation Facility (WRF) to the Occoquan Reservoir during the warmer months has been proven to be an efficient way of maintaining the water quality of the reservoir. During the warmer months, the water body became thermally stratified, resulting in hypolimnetic anoxia and the subsequent release of undesired matters from the reduced sediments. At the end of the warmer months, the temperature began to decrease, and by the beginning of winter, oxygen became ubiquitous in water because of fall turnover. This condition remained stable until the following thermal stratification; …

Analysis Of Spatial Discrepancies Between 76-Foot Close Range Photogrammetric And Terrestrial-Lidar Models, Abdoul K. Ouangre

Electronic Theses and Dissertations

This study presents an analysis of the accuracy of a 3D model generated by two different methods. In the first method, the 3D model is generated via Laser Scanning. In the second method, the 3D model is generated via Close-range Photogrammetry from a drone flying at 76 feet above the ground. Photogrammetry is a photo-based technique that uses images to generate 3D models of objects where distances could be extracted from. Close-range photogrammetry is the approach of generating a 3D model from a camera placed anywhere between 1 foot and 1000 feet relative to the object. Terrestrial LiDAR is the …