Louisiana coastal marshes were heavily impacted by the 2010 Deepwater Horizon oil spill. MC252 oil pollution in coastal marshes lead to the exposure of biota to polycyclic aromatic hydrocarbons (PAHs). PAHs are persistent organic pollutants that can reside and accumulate in marsh biota. The aim of this study was to investigate the uptake mechanisms of PAHs by Spartina alterniflora at heavily oiled Bay Jimmy marsh in Barataria Basin, Louisiana. Study objectives were to quantify and investigate the uptake mechanisms of PAHs in the leaves of Spartina. The plant/air partitioning of PAHs was studied using a fugacity approach to determine their partitioning coefficients. Semipermeable membrane devices (SPMDs) were utilized in a parallel study of the uptake of PAHs from the marsh surface and air. Sampling was between June 2016 and February 2017. A three-step sequential extraction procedure was applied for analysis of PAHs in Spartina leaves. At the field, particulates deposited on Spartina leaves were washed with EDTA solution followed by dichloromethane to dissolve the cuticle. Leaf tissues were extracted by the accelerated solvent extraction method. PAHs in SPMDs were extracted via dialysis with hexane. A laboratory scale fugacity meter was designed to study plant/air partitioning of PAHs. PAHs were quantified in selective ion monitoring mode connected with a mass selective detector. Similar PAHs profiles in Spartina leaf tissues and SPMDs suggested the cycling of PAHs at Bay Jimmy. Naphthalenes accumulated twice more than phenanthrenes in Spartina leaves and SPMDs. PAHs were sequestered in leaf tissues than the cuticle. Statistically significant correlation (p <0.05) of PAHs in plant leaves and SPMDs were as high as 97%. Soil analysis revealed naphthalenes and phenanthrenes to total PAHs fraction of less than 20%. Results indicated that air-leaf-partitioning was the dominant uptake route of PAHs accumulation in Spartina. Lower plant/air partition coefficients of naphthalenes than phenanthrenes from the fugacity experiment suggested the accumulation of lower molecular weight PAHs in greater quantities. Temporal trends revealed seasonal variability of PAHs accumulation in Spartina and SPMDs. This study demonstrated the efficiency of Spartina cuticle measurements as passive samplers for assessing the pace of natural recovery in marsh systems.

Louisiana possesses over 350,000 acres of unique floating vegetated systems known as floating marshes or flotants. Due to their buoyant nature, floating marshes are susceptible to high energy changes in the hydrodynamic environment that may result from proposed river diversion projects which introduce flow to areas that are typically somewhat isolated. The overall goal of this research is to improve the understanding of how exposed flotants deteriorate under increased hydrodynamic stresses. More specifically, this thesis aims to answer how the material limits of floating marshes can be measured and how the mats interact with hydrodynamics. The two primary objectives are: 1) Develop a technique for accurate, in-situ measurement vegetative mat root-soil matrix material properties; and 2) Develop a means for predicting floating marsh washout (critical velocities) through numerically modeled derived empirical relationships.  The device constructed to capture the tensile properties of the vegetative mats, called the Marsh Mat Tensile Strength Tester (MMTST), successfully produced full stress-strain profiles including the Youngs modulus, yield stress, and ultimate strength of a root-soil matrix (sod). The estimated mean Youngs modulus, yield stress, and ultimate strength values (sod) were found to be 31.95 kPa, 9.58 kPa, and 9.91 kPa, respectively. Next, flows around 25 idealized mat geometries were simulated with 2-D & 3-D Fluent models. Mat-specific drag coefficients (Cd,m) were found ranging from 1.084-1.645 depending on mat aspect ratio. An equation developed for predicting Cd,m successfully estimated the modeled drag coefficients with a mean percentage error of 2.33%. A finite element analysis (FEA) was performed on the 25 mat shapes using the predicted drag forces and the material properties measured by the MMTST. By applying various failure criteria (Fc), a correlation was found between the modified mat width-to-length aspect ratio (𝛽) and critical velocity (Vc). The critical velocities ranged from 0.31-1.48 m/s depending on mat aspect ratio and material properties. The general equation developed for predicting floating marsh failure due to flow, in the form: Vc = f(𝛽,Fc), performed well with a mean percentage error of 3.33% relative to the unique values directly extracted from the FEA.

The studies conducted in this thesis evaluate the safety benefits of a blind spot warning (BSW) application and a do not pass warning (DNPW) application at low, medium, and high market penetrations (MP) of connected vehicles (CV) using a high-fidelity driving simulator. Using vehicle-to-vehicle (V2V) communication, CVs can exchange information to alert drivers of potential safety hazards and reduce potential crashes during lane change and overtaking maneuvers. A CV testbed was developed to relay visual and auditory warnings when dangerous thresholds were met for each application. For the BSW a proximity-based threshold was used to trigger a warning as a CV approached the simulator vehicles blind spot. To test the impact of MP on the effectiveness of the BSW Application, four simulation scenarios were developed with zero, 25%, 50%, and 75% MP rates. Drivers were instructed to perform lane change maneuvers whenever they felt comfortable. For each lane change, the simulator vehicle and blind spot vehicles speeds and gaps were collected. Two non-parametric tests, along with a post-hoc pairwise test, were used to compare the significance each MP had on the minimum time-to-collision (TTC) and the variance of the speed of the subject vehicle and blind spot vehicle. A similar study was performed to test the DNPW application. For this pilot study, a TTC threshold was designed to warn drivers of oncoming vehicles on a two-lane two-way rural roadway. Participants performed five overtaking maneuvers within each experiment, totaling to 30 maneuvers for each MP. The safety of each maneuver was evaluated by the TTC between the simulator and oncoming vehicle at the beginning and end of the maneuver, the time spent in the opposing lane, the headway between the simulator vehicle and the vehicle in the right lane before the maneuver, and the tailway between the two vehicles following the maneuver. The results of both studies indicated that a medium MP (50%) is required to achieve significant safety improvement from CV safety applications.

The Expanded Small-Scale Physical Model (ESSPM) is a distorted-scale, moveable bed model that will complement numerical and field studies studying management strategies in the lower ~140 miles of the Mississippi River and their effect on flooding, navigation and coastal restoration. It is recognized that relative sea level rise (RSLR), the combination of eustatic sea level rise (ESLR) and subsidence, will have an impact on the hydraulics and sediment transport in the lower River. However, it is physically impossible to replicate subsidence in the ESSPM; thus, future RSLR conditions will be experimentally simulated by raising Gulf of Mexico (GoM) levels commensurate to future RSLR. The purpose of this thesis is to develop 1- and 2-D numerical models to quantitatively compare the hydraulics and sediment transport characteristics at both the ESSPM and prototype scales under future RSLR conditions in two ways: (1) the natural conditions where river bathymetry is subsided and GoM levels are raised independently; and (2) ESSPM conditions where the combined effect is modeled as ESLR. HEC-RAS 5.0.3 was used to develop 1-D prototype and distorted models, as well as a 2-D prototype model. The 1-D prototype model was first calibrated and validated for 2009 and 2010 Mississippi River conditions. The prototype geometry was replicated at the ESSPM distortion (i.e. the vertical and horizontal axes were scaled 1:400 and 1:6000, respectively). A grid was created from the 1-D cross sections to create the 2-D prototype model. Five future subsidence and ESLR scenarios were simulated for each model under RSLR and model conditions (ESSPM SLR) to compare depth, bed shear stress, and velocity. Differences of depth between RSLR and ESSPM SLR decrease with each station approaching the downstream boundary condition of equal depths with maximum RMSE percentages still below 3%. Velocity and bed shear stress are roughly the same between RSLR and ESSPM SLR and start to deviate at Empire (RM 29.5) and Venice (RM 10.7) with significant differences. ESSPM SLR has a smaller impact on ESSPM model compared to prototype model, and differences in both models increase with each scenario. The 2-D prototype model estimates insignificant differences in all parameters compared to 1-D models.

Distracted driving has long been acknowledged as one of the leading causes of death or injury in roadway crashes. The focus of past research has been mainly on the change in driving performance due to distracted driving. However, only a few studies attempted to predict the type of distraction based on driving performance measures. In addition, past studies have proven that driving performance is influenced by the drivers socioeconomic characteristics, while not many studies have attempted to quantify that influence. In essence, this study utilizes the rich SHRP 2 Naturalistic Driving Study (NDS) database to (a) develop a model for detecting the likelihood of a drivers involvement in secondary tasks from distinctive attributes of driving performance, and (b) develop a grading system to quantify the crash risk associated with socioeconomic characteristics and distracted driving. The results show that the developed neural network models were able to detect the drivers involvement in calling, texting, and passenger interaction with an accuracy of 99.6%, 99.1%, and 100%, respectively. These results show that the selected driving performance attributes were effective in detecting the associated secondary tasks with driving performance. On the other hand, the grading system was developed by three main parameters: the crash risk coefficient, the significance level coefficient, and the category contribution coefficient. At the end, each drivers crash risk index could be calculated based on his or her socioeconomic characteristics. The developed detection models and the systematic grading process could assist the insurance company to identify a drivers probability of conducting distracted driving and assisting the development of cellphone banning regulation by states Departments of Transportation.

Following the Deepwater Horizon oil spill in April, 2010, hard structures were constructed to deter oil migration into sensitive marsh areas behind Fourchon Beach, LA These hard structures created conditions for accumulation and burial of oil across an 8 foot deep beach vertical profile. Buried oil persists in these areas due to anaerobic conditions of beach groundwater. The objectives of this thesis are to compare the rate and extent of biodegradation of 3-ring PAHs in crude oil deposits from the surface and subsurface, and to investigate effects on beach groundwater after introduction of O2. Field samples were removed from 2011-2016 from the area including oil samples from depth with a Geoprobe, oil-sand aggregates distributed over the surface of the beach, free oil floating on the groundwater surface and oil recovered during excavations used as part of response in 2013 and 2015. Weathering of PAHs was estimated based on ratios of alkylated phenanthrenes and dibenzothiophenes to poorly biodegradable chrysenes. The average weathering ratio was 0.731±0.22 for phenanthrenes and 0.48±0.22 for dibenzothiophenes. Results indicate that oil weathers significantly differently based on location in the beach vertical profile. Oil above the groundwater table was significantly more than buried oil below groundwater level. Oil above the groundwater table weathers up to 2 orders of magnitude faster than buried oil below groundwater level. A field trial of in situ biostimulation demonstrated the ability to amend groundwater with oxygen. Weathering of oil buried below the groundwater surface was seen. Terminal electron acceptors and nutrients were evaluated based on repetitive (pre and post oxygen introduction) groundwater analysis of O2, nitrate, nitrite, ferrous and ferric iron, sulfate, sulfide, ammonium, orthophosphate, pH and alkalinity. Results suggest that oxygenated groundwater is confined locally to emitter wells due to slow groundwater movement. Nutrient concentrations pH and temperature are sufficient for microbial function; however the hypersaline nature of the groundwater may limit microbe population.

Temperature differentials (TD) between the target laydown and actual laydown temperatures of asphalt paving mixtures have been noticed and measured since the late 1990s. Since then, numerous research studies conducted on the phenomena found inconclusive conclusions regarding the effects of TD on the initial pavement quality and the long-term performance. The objective of this study was to evaluate the effects of different levels of TD on the initial quality and the long-term performance of asphalt pavements by evaluating the core density and laboratory measured performance characteristics, respectively. Through the evaluation, it was also aimed to ascertain and establish allowable TD range, which would not adversely affect the quality and performance of the pavements. In addition, impacts of construction related factors such as using different types of material transfer vehicles (MTV), different contractors, ambient temperature, etc. on temperature and density differentials were also evaluated. Seven asphalt rehabilitation projects across Louisiana were selected for this study differing in use of mixture type, laydown temperature, mix layer, month of paving, etc. A multi-sensory infrared temperature scanning bar (IR-bar) system and a hand-held portable thermal camera were used to measure the temperature differentials. Field core samples were collected from thermally segregated areas, which were then evaluated in the laboratory using the Density test, Semi-Circular Bending (SCB) test, Loaded Wheel Tracking (LWT) test, and Indirect Tensile Dynamic Modulus (IDT|E*|) test. Two distinct temperature patterns were observed throughout all projects. Cyclic temperature patterns showing regular high-low temperature fluctuations while irregular patterns caused by work stoppages were present in all thermal profiles. Laboratory test results showed pavement density and SCB Jc values correlated strongly with the temperatures measured prior to compaction. LWT, and IDT|E*| test results showed a decreasing trend in rut depth and stiffness with increasing TD severity level. Furthermore, IR-bar temperature readings were used to measure consistency by defining one qualitative (standard deviation) and one quantitative (%severity levels) parameter. Comparisons with construction factors showed that use of MTV increased consistency in temperature. Based on the results of this study, IR-bar system was found useful to monitor consistency in laydown temperatures. However temperature monitoring at breakdown compaction was observed to present actual effect of temperature differential on pavement performance. To ensure that asphalt mixture gets compacted at target temperature, it was strongly advised to instruct breakdown compactor operator to follow the paver closely. Additionally, the use of tarps over un-compacted portion of asphalt mat is strongly advised to prevent significant temperature loss during paver stops.

Healing by means of induction heating is promising, however the effectiveness of this technology is yet to be demonstrated due to limited studies on cracking damage and fracture resistance property recoveries after healing. The objective of this study was to test the hypothesis that a new generation of asphaltic materials could be artificially healed while in-service by embedding metallic fibers in the mix and by applying a magnetic field at the surface. To achieve this objective, an open-graded friction course (OGFC) was successfully designed and prepared to incorporate up to 5% steel and aluminum fibers by weight of the mix. Based on results of the study, it was found that the control mix and the mix prepared with aluminum fibers exhibited a greater ultimate load at failure prior to healing, than those specimens with steel fibers. Yet, differences were not statistically significant. The induction heating experiment was conducted successfully and showed the feasibility of inducing Eddy current in the metallic fibers without contact to the specimens. After healing, the control mix displayed the highest ultimate load after healing, although unsuccessfully heated through Eddy current; yet neither were these differences statistically significant. These outcomes indicate that other healing mechanisms were present due to the recovery period, which allowed the control specimens to heal during the rest period. Healing efficiency showed the highest results for the control specimen that approached 85%. The healing efficiency for the specimen with aluminum and steel fibers was 72 and 62%, respectively. Microscopic image analysis demonstrated that induced cracks healed efficiently during the healing period. Additionally, Loaded Wheel Track (LWT) test was conducted to analyze the rutting performance of the asphalt mixtures with steel and aluminum fibers. The results indicated that the mixture with a high percentage of steel fibers (5.0%) performed better than the ones with less content, while the mixtures with aluminum fibers did not perform well.

<p> The objective of this research is to develop a simple and innovative technology that effectively lowers chemical concentrations to meet Environment Protection Agency (EPA) drinking water regulations. This study focuses on fabric inclined settling screen development for application to small community drinking water treatment systems to help them with compliance, particularly with disinfection by-products (DBPs) through enhanced solids contact. The technology developed combines fabric filters with the traditional inclined plate concept. Fabric material performance and serviceability was first checked by exposure to a drinking water treatment environment and then measuring turbidity, total dissolved organic carbon, and UV254. The study suggests a product like Pureflo (a polyester) is the more appropriate material in acidic and neutral conditions and one like Surefil (rayon/polyester blend) is the more appropriate material in basic conditions. The Pureflo product was used in bench scale systems to determine performance of the designed fabric inclined settling screen. Experiments with different coagulants, different angle, and different layers of fabric screens was conducted. A pilot scale system was set up in Vandalia, MO to test the feasibility of the fabric screen of turbidity, TOC, UV254, and TTHM removal. Results indicated that screens made from pureflo with angles from 30&deg; through 70&deg; under acidic condition have positive effects on sedimentation enhancement.</p>

<p> Minimizing coastal wetland loss is a high priority in coastal areas throughout the world. Commonly used protection methods are costly, and may have negative impacts on the surrounding areas. The Wave Suppression and Sediment Collection (WSSC) system is an alternative shoreline protection structure. Primary goals of this study are to evaluate the sediment collection performance of three WSSC units under different sand conditions, to determine the performance characteristics of the units in terms of energy coefficients, and to validate a Computational Fluid Dynamic (CFD) model to determine the parameters governing wave attenuation. Sand collection results showed the units collected a minimum of 25% more fine sand than coarse, and that collection was affected by pipe size and row location. A mass transfer model was developed to predict the collection rate of sands based on wave and sand characteristics. The model fit experimental data well, with R2 values over 0.84 for three units and two different sands. A mass transfer coefficient alpha (a) was used within the model to compare the actual sand collection to the predicted amount. Resulting alpha values showed that sediment collection efficiency is governed by open area and pipe location within the devices. Performance characterization showed the WSSC units have wave reflections of 0.45 to 0.80, wave transmissions ranging from 0.10 to 0.40, and wave energy dissipation between 0.50 and 0.90, depending upon the unit and wave conditions. The WSSC units reflect more wave energy and transmit less energy compared to other breakwaters. The CFD model was validated using experimental velocity measurements. Statistical tests showed model velocities were not significantly different from experimental data. Units were modeled parametrically using CFD. Results indicated that wave reduction could be increased by decreasing pipe diameter, reducing the face slope, or increasing the number of rows.</p>