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Microstructural Analysis Of Thermoelastic Response, Nonlinear Creep, And Pervasive Cracking In Heterogeneous Materials, Alden C. Cook

Electronic Theses and Dissertations

This dissertation is concerned with the development of robust numerical solution procedures for the generalized micromechanical analysis of linear and nonlinear constitutive behavior in heterogeneous materials. Although the methods developed are applicable in many engineering, geological, and materials science fields, three main areas are explored in this work. First, a numerical methodology is presented for the thermomechanical analysis of heterogeneous materials with a special focus on real polycrystalline microstructures obtained using electron backscatter diffraction techniques. Asymptotic expansion homogenization and finite element analysis are employed for micromechanical analysis of polycrystalline materials. Effective thermoelastic properties of polycrystalline materials are determined and compared …

Geotechnical Properties Of The Travis Peak (Hosston) Formation In East Texas: A Compressive And Tensile Strength Analysis Using Regression Analysis., Pawan Kakarla

Electronic Theses and Dissertations

The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Geotechnical engineering is the branch of civil engineering which works on the principles of soil and rock mechanics to evaluate subsurface conditions, stability of slopes, foundations of structures and construction of earthworks. The main focus of this study was to calculate the strength of Lower Cretaceous Travis Peak Formation rocks of East Texas and to check the accuracy by comparing it with Regression analysis. The parameters which were used were the Uniaxial Compression …

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …

Reflectivity Of Light Emitting Diodes (Led) And Incandescent Lights On Concrete And Asphalt Pavements., Jeremy Elliott Rice

Electronic Theses and Dissertations

The purpose of this study is to investigate the reflectivity of light on concrete and asphalt pavement systems. In 1983, the Illuminating Engineering Society (IES) published the first recommended practice (RP-8) for the design of roadway and parking lot lighting. This design method implemented empirically tested factors which were defined as the “reduced luminance coefficients” or the R-Tables. The R-Tables are essential for proper design of light pole installation dimensions, required power, and the distribution of light. The originally tested pavements are not necessarily representative of modern pavement materials used today. Moreover, recent Light Emitting Diodes (LED) are a relatively …

Analysis And Recommendations To Improve Traffic Safety & Flow For Pedestrians Bicyclists And Motorists Along Franklin Street, Matthew Pelletier

Electronic Theses and Dissertations

Franklin Street is a minor arterial servicing Portland, Maine that connects Commercial Street and Route 1 to I-295 and has been a target for redevelopment for some time. Franklin is the epitome of traffic congestion, and has unsafe conditions for pedestrians, bicyclists and motorists alike. Portland is the biggest city in Maine and is an important hub for employment, housing and tourism throughout the year. As the city grows, there is a greater demand to build more sustainable, multi-use streets to service all modes of transportation that supports business development, open space and growth. This new vision is being applied …

Integrating Laminated Strand Lumber And Lumber From Northeastern U.S. Forests Into Cross-Laminated Timber, Nicholas Matthew Willey

Electronic Theses and Dissertations

The objective of this research was to conduct a technical assessment of the engineering properties of cross-laminated timber (CLT) made from local Northeastern lumber, laminated strand lumber (LSL) and mixtures of the two. The technical assessment provided the bending and shear strength and stiffnesses values for select CLT configurations, which were used to determine the feasibility of using local Northeastern lumber and LSL in CLT. Experimental lay-up designs were created for six three-layer CLT configurations using Spruce-Pine-Fir (South) (SPFs) No.2 and better and 1.35E LSL. Preliminary shear block tests were run to determine the optimal spread rate, and a board …

Improvement Of Soil Spring Model For The Analysis Of Buried Arch Structures, Leo N. Helderman

Electronic Theses and Dissertations

The University of Maine has developed concrete filled fiber-reinforced polymer (FRP) tubes (CFFTs) for use in bridge construction. A finite element model was previously developed to analyze these buried arch structures during construction, service live load, and ultimate load. Two shortcomings in that model include how the load distribution method and the soil reaction due to construction and service loads are modeled. There were two objectives to this research: to make a user-friendly software package to analyze a variety of buried arch structures and to improve the existing model to better predict the soil-structure interaction. Prototype software was developed complete …

The Influence Of Superabsorbent Polymer (Cassava Startch) On The Rheological Behavior Of Cement Pastes., James Wong

Electronic Theses and Dissertations

Rheological properties are the properties typically reference flow properties of concrete and are related to processing, construction, and setting. The purpose of this research was to investigate the influence of superabsorbent polymers (SAP) and superplasticizer (SP) on rheological properties, specifically of cement pastes with 0.35, 0.45 and 0.55 water-to-cement ratios (w/c), SAP water replacement dosages of 0%, 5%, 10%, 15%, 20% and 25% were tested. Tests included rheological measurements of yield stress, viscosity using the Bingham equation and the flow behavior index using Herschel-Bulkley equation. Slump diameter tests were used to measure flow of the cement pastes. Comparisons of slump …

Evaluation Of Crash Modification Factors And Functions Including Time Trends At Intersections, Jung-Han Wang

Electronic Theses and Dissertations

Traffic demand has increased as population increased. The US population reached 313,914,040 in 2012 (US Census Bureau, 2015). Increased travel demand may have potential impact on roadway safety and the operational characteristics of roadways. Total crashes and injury crashes at intersections accounted for 40% and 44% of traffic crashes, respectively, on US roadways in 2007 according to the Intersection Safety Issue Brief (FHWA, 2009). Traffic researchers and engineers have developed a quantitative measure of the safety effectiveness of treatments in the form of crash modification factors (CMF). Based on CMFs from multiple studies, the Highway Safety Manual (HSM) Part D …

Investigation Of Infrared Thermography For Subsurface Damage Detection Of Concrete Structures, Shuhei Hiasa

Electronic Theses and Dissertations

Deterioration of road infrastructure arises from aging and various other factors. Consequently, inspection and maintenance have been a serious worldwide problem. In the United States, degradation of concrete bridge decks is a widespread problem among several bridge components. In order to prevent the impending degradation of bridges, periodic inspection and proper maintenance are indispensable. However, the transportation system faces unprecedented challenges because the number of aging bridges is increasing under limited resources, both in terms of budget and personnel. Therefore, innovative technologies and processes that enable bridge owners to inspect and evaluate bridge conditions more effectively and efficiently with less …

Analysis Of Driving Behavior At Expressway Toll Plazas Using Driving Simulator, Moatz Saad

Electronic Theses and Dissertations

The objective of this study is to analyze the driving behavior at toll plazas by examining multiple scenarios using a driving simulator to study the effect of different options including different path decisions, various signs, arrow markings, traffic conditions, and extending auxiliary lanes before and after the toll plaza on the driving behavior. Also, this study focuses on investigating the effect of drivers' characteristics on the dangerous driving behavior (e.g. speed variation, sudden lane change, drivers' confusion). Safety and efficiency are the fundamental goals that transportation engineering is always seeking for the design of highways. Transportation agencies have a crucial …

Experimental Study Of Sinkhole Failure Related To Groundwater Level Drops, Mohamed Alrowaimi

Electronic Theses and Dissertations

Sinkholes are natural geohazard phenomena that cause damage to property and may lead to loss of life. They can also cause added pollution to the aquifer by draining unfiltered water from streams, wetland, and lakes into the aquifer. Sinkholes occur in a very distinctive karst geology where carbonate, limestone, dolomite, or gypsum, are encountered as the bedrock that can naturally be dissolved by groundwater circulating through them. Sinkholes can occur gradually or suddenly with catastrophic impact depending on the geology and hydrology of the area. Predicting the formation and the collapse of a sinkhole based on the current ground investigation …

Bioremediation Of A Trichloroethene Dnapl Source Zone Utilizing A Partitioning Electron Donor - Field Implementation, Joseph Bartlett

Electronic Theses and Dissertations

Trichloroethene (TCE) is a chlorinated volatile organic compound (CVOC) that can be found in industrial and household products. It is typically used as a solvent or degreaser. TCE can have detrimental health impacts and is known to be carcinogenic to humans. Federal and state regulatory drivers determine the need to assess and remediate soil and groundwater contaminated with CVOCs. There are many different methods for remediation; however, bioremediation has the ability to breakdown TCE all the way to harmless gasses (ethene and ethane). Bioremediation requires dechlorinating microbes (indigenous or augmented), electron donor (food source), and an electron acceptor (CVOCs). Electron …

Impact Of Dynamic Message Signs On Driver Behavior Under Reduced Visibility Conditions, Ryan Selby

Electronic Theses and Dissertations

Fog along roadways is a dangerous hazard that leads to crashes resulting from limited visibility. Low visibility gives drivers less time to react to potential obstacles that can suddenly appear and require immediate action. To solve this issue, early warning systems involving Dynamic Message Signs or other types of devices are used to alert drivers of the impending visibility condition so that they are prepared. This research focuses on testing the effectiveness of one form of warning systems to investigate how it impacts driver behavior in foggy conditions. To accomplish this objective, a simulation study is developed to test variables …

Control Of Metal-Release And Tuberculation In A Silica-Laden Groundwater Distribution System On The Volcanic Island Of Lana'i, Samantha Myers

Electronic Theses and Dissertations

A corrosion control study for two distinct water distribution systems (WDS) has been completed for the Pulama Lana'i Water Company (Pulama). This project evaluated the use of chemical inhibitors to control corrosion and tuberculation within the Manele Bay WDS and the Lana'i City WDS. Pulama provides water to a population of 3,100 residents and is considering incorporating alternative water supplies in the future. Hence, knowing baseline corrosion rates within the WDS was desired. Several groundwater wells feed each of the WDS's; however, water quality between wells varies. Well water supplied to the WDS's is generally of high quality, therefore, the …

Application Of Landfill Treatment Approaches For The Stabilization Of Municipal Solid Waste, Stephanie Bolyard

Electronic Theses and Dissertations

This research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ aeration were evaluated. After extensive treatment of the waste in the flushing bioreactor (FB) scenarios, the overall biodegradable fraction was reduced relative to mature waste. Leachate quality improved for all FBs but through different mechanisms. …

Microscopic Safety Evaluation And Prediction For Special Expressway Facilities, Ling Wang

Electronic Theses and Dissertations

Expressways are of great importance and serve as the backbone of a roadway system. One of the reasons why expressways increase travel speeds and provide high level of services is that limited access is provided to permit vehicles to enter or exit expressways. Entering and exiting of vehicles are accomplished through interchanges, which consist of several ramps, thus the spacing between ramps is important. A weaving segment might form when an on-ramp is closely followed by an off-ramp. The geometric design of ramps and the traffic behavior of weaving segments are different from other expressway segments. These differences result in …

Effects Of Climate Change And Anthropogenic Activities On The Everglades Landscape., Daljit Sandhu

Electronic Theses and Dissertations

The Everglades has been experiencing major changes, both climatic and anthropogenic, such that the landscape is experiencing additional stresses and forcings leading it away from its natural equilibrium. The land within and surrounding the Everglades has undergone severe modifications that may have detrimental effects on wildlife and natural features, such as rivers and landscape connectivity. Here in this study, the main focus is on understanding and quantifying hydrologic and geomorphic signatures of climatic and anthropogenic changes on the Everglades landscape. For this, in particular, available data on natural hydrological processes was used, such as rainfall, groundwater elevation, streamflow as well …

Remote Sensing Of Coastal Wetlands: Long Term Vegetation Stress Assessment And Data Enhancement Technique, Subrina Tahsin

Electronic Theses and Dissertations

Apalachicola Bay in the Florida panhandle is home to a rich variety of salt water and freshwater wetlands but unfortunately is also subject to a wide range of hydrologic extreme events. Extreme hydrologic events such as hurricanes and droughts continuously threaten the area. The impact of hurricane and drought on both fresh and salt water wetlands was investigated over the time period from 2000 to 2015 in Apalachicola Bay using spatio-temporal changes in the Landsat based NDVI. Results indicate that salt water wetlands were more resilient than fresh water wetlands. Results also suggest that in response to hurricanes, the coastal …

Understanding Hydroclimatic Controls On Stream Network Dynamics Using Lidar Data, Seoyoung Kim

Electronic Theses and Dissertations

This dissertation investigates the hydroclimatic controls on drainage network dynamics and characterizes the variation of drainage density in various climate regions. The methods were developed to extract the valley and wet channel networks based on Light Detection and Ranging (LiDAR) data including the elevation and intensity of laser returns. The study watersheds were selected based on the availability of streamflow observations and LiDAR data. Climate aridity index was used as a quantitative indicator for climate. The climate controls on drainage density were re-visited using watersheds with minimal anthropogenic interferences and compared with the U-shape relationship reported in the previous studies. …

Determining The Feasibility Of Using Micro Simulation To Asses Safety Of Pedestrian Crossings, Jenner Darius

Electronic Theses and Dissertations

For the past several decades, pedestrian safety has been an oncoming issue that has thrown the area of transportation engineering into a frenzy. Pedestrian safety has become predominantly one of the leading causes of fatalities in traffic accidents. Florida has been reported as one of the leading states in pedestrian fatalities with 2.56 fatality rate per 100,000 population and about 20 percent of all traffic fatalities in the state of Florida. Nonetheless, as research is being done and hypotheses are being calibrated and produced, there has to be a way of measuring and determining the number of pedestrian-to-vehicle conflicts without …

The Effect Of Glycerol On Readily Biodegradable Chemical Oxygen Demand (Rbcod) In A Wastewater Stream, Rojina Rawut

Electronic Theses and Dissertations

This study evaluated the short-term effects of glycerol addition on readily biodegradable (RB) chemical oxygen demand (COD) in a carbon limited wastewater influent. The presence of an RB fraction provides with a suitable substrate for microorganisms to produce volatile fatty acids (VFA). The oxygen utilization rate (OUR) has been used to evaluate the oxygen consumption for RB substrate in wastewater. Wastewater with low organic content contains limited RB substrate, and thus, additional carbon source is required to improve biological treatment capability. Acetate, propionate, methanol, and glycerol are the commonly available carbon sources for biological treatment process. However, the cost of …

Modeling Wastewater Indicators And Effects Of Contaminant Removal Strategies On Groundwater And Spring Discharge In A Karst Aquifer, Erin Reed

Electronic Theses and Dissertations

This dissertation reports on research related to groundwater and contaminant transport to the Volusia Blue Spring (VBS), an Outstanding Florida Water Body located in Volusia County (Florida). The integration of springshed water quality and contaminant fate and transport (CFT) modeling played key roles in the evaluation of anthropogenic recharge impacts on VBS. To study anthropogenic recharge into the karst limestone aquifer, wastewater effluent, golf course ponds, septic tanks, groundwater monitoring wells, and VBS discharge were sampled for boron, nitrate-nitrogen, nitrate-oxygen and their isotopes spatially throughout the VBS springshed. Data related to natural water features, rainfall, land use, water use, treated …

Using Fluorescence To Characterize Four Day Simulated Distribution System Trihalomethane Content In Florida Groundwaters, Jonathan Ousley

Electronic Theses and Dissertations

The United States Environmental Protection Agency (USEPA) regulates public water systems and has established limits for certain disinfection by products (DBPs) that have been linked to health effects, such as bladder cancer. The regulation of DBPs, specifically total trihalomethanes (TTHMs) and haloacetic acids (HAAs), have encouraged water treatment professionals to assess the type and amount of organic precursors in their supplies. Three of the more common water quality parameters that are monitored as DBP surrogates include dissolved organic carbon (DOC), ultraviolet absorbance (UV254), and specific ultraviolet absorbance (SUVA). Although DOC, UV254, and SUVA have been effectively correlated to DBP formation, …

The Effect Of Building Information Modeling On Design And Construction Industry, Yahya Alassaf

Electronic Theses and Dissertations

Construction industry's evolution is, historically, in the lowest level, if compared to other industries, such as auto manufacturing. Construction is a multidisciplinary industry, considering that designers, contractors, and owners are all involved in the same project, each one seeking their own interests. The complex environment surrounding design and construction makes the decision-makers hesitate about adopting new methodology. Building Information Modeling (BIM) is a new method and technology, which can improve both the design and the construction processes. The adoption of BIM is increasing significantly over the last years, and its effects can be seen on real life projects. In order …

An Integrated Hydrodynamic-Marsh Model With Applications In Fluvial, Marine, And Mixed Estuarine Systems, Karim Alizad

Electronic Theses and Dissertations

Coastal wetlands experience fluctuating productivity when subjected to various stressors. One of the most impactful stressors is sea level rise (SLR) associated with global warming. Research has shown that under SLR, salt marshes may not have time to establish an equilibrium with sea level and may migrate landward or become open water. Salt marsh systems play an important role in the coastal ecosystem by providing intertidal habitats and food for birds, fish, crabs, mussels, and other animals. They also protect shorelines by dissipating flow and damping wave energy through an increase in drag forces. Due to the serious consequences of …

Mechanistic Behavior Of Uhpc And Uhpc Composite Structural Components, Munaf Al-Ramahee

Electronic Theses and Dissertations

The resistance of reinforced concrete is mobilized through the composite action of two materials with different mechanical behaviors and physical features. Enabling the composite action requires a transfer mechanism between the concrete and the reinforcement which is referred to as bond. The bond model can be defined as a traction-slip relation tangent to the interface. The bond strength between different types of concrete, internal reinforcement, and external reinforcement has been of interest to structural engineers for decades. Experimental tests have been carried out to validate the existing bond models and introduce new bond models for special cases of concrete or …

Reuse Of Aqueous Waste Streams For Transportation-Related Applications, Gregory L. Hansen

Electronic Theses and Dissertations

Aqueous waste streams produced from commercial, industrial, and municipal processes may be potentially reused for transportation applications. The objectives of this project were to identify potential transportation-related applications for aqueous waste streams available in South Dakota, develop guidance for the beneficial reuse of aqueous waste streams, and evaluate the reuse of MIEX® brine generated by the Watertown Municipal Water Treatment Plant (WMWTP). This study identified many aqueous wastes from municipal water and wastewater treatment facilities, industrial and agricultural processes in South Dakota that can be potentially used for ice and dust control. Beneficial reuse of these waste streams requires a …

Impact Of The Longer Change And Clearance Intervals On Signalized Intersections And Corridors, Mohammed Alfawzan

Electronic Theses and Dissertations

Evaluating the impact of longer change and clearance intervals on signalized intersections and corridors is the main goal of this study. In fact, the Florida department of Transportation (FDOT) has adopted a new signal retiming effort in a number of signalized intersections along several corridors. The Orange County started implementing the new signal timing from December, 2013 and completed it in June, 2015. The other objective of this new signal timing is to minimize the red light running rate. This study is dedicated to investigate the signal retiming effort adopted by the FDOT and how the new signal timing might …

Modeling Mass Transfer And Assessing Cost And Performance Of A Hollow Fiber Nanofiltration Membrane Process, David Yonge

Electronic Theses and Dissertations

Bench-scale water treatment testing of three next generation hollow-fiber (HF) nanofiltration (NF) membranes was conducted to characterize divalent ion rejection capabilities and investigate removal mechanisms. Existing mathematical models were investigated to describe solute transport using synthetic magnesium sulfate solutions including the size exclusion model, homogenous solution diffusion (HSD) model, dimensional analysis, and the HSD model incorporating film theory. Solute transport for two of the membranes were described by HSD theory and were predictive of their 90% divalent ion removal. A third membrane was more accurately modeled using size exclusion and was found to be predictive of its 40% divalent ion …