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>

<p> Ordered Mesoporous Carbons (OMCs) with well-controlled pore structure and narrow pore size distribution demonstrated great potential as highly functional adsorbents. The pore size and surface chemistry of OMCs were considered two of the most important factors that affect the adsorption capacity of organic compounds. The objective of this study is to optimize the structure of OMCs for resorcinol adsorption by changing the pore size and oxygen content using computational approach. New rhombic OMC models with varied pore size and oxygen content were constructed using Materials Visualizer module. The specific surface area, total pore volume, small angle X-ray diffraction patterns, and resorcinol adsorption capacity results were calculated by Forcite and sorption module in Materials Studio package. The simulation results were validated by the experimental data. Experimentally, the OMCs were synthesized using sucrose as carbon precursor by hard-template method. The tunable pore size (4nm to 15nm) and oxygen content of the OMCs are obtained by adjusting the amount of boric acid as a pore-expanding reagent. The experimental results, such as BET surface area, X-ray power diffraction patterns, and adsorption capacity of resorcinol, were compared with the simulation results. The optimal pore size of OMC for resorcinol removal was found to be 6 nm. The simulation results confirmed that oxygen containing functional group was an important factor for adsorption on OMCs. The improvement of adsorption capacity was not so significant comparing with the influence of specific surface area, since the adsorption process was a more of a physical process rather than a process with chemical interaction.</p>

Coastal deltaic floodplains provide an important ecosystem service by removing or retaining nitrate from enriched riverine water. Wetland plants, soils, and microbes within these floodplains use nitrate through uptake, burial, and denitrification, thereby reducing the impact of nitrate on algal blooms and hypoxia in the Gulf of Mexico. However, these processes depend on the physical, biological, and chemical conditions within the floodplain. Understanding and characterizing the hydrodynamics of these systems and the relative impact of river, tide, and wind forcings are the first steps in understanding the biogeochemical processes controlling nitrate removal. Motivated by the desire to identify biogeochemical hotspots within coastal deltaic floodplains, this project focuses on modeling the hydrodynamics of these complex wetland ecosystems. Biogeochemical hotspots occur where anaerobic soils, sufficient organic carbon supply, longer residence times, and warmer water temperatures create optimal conditions for processes such as denitrification. The latter two conditions are strongly controlled by the hydrodynamics of the system. A Delft3D-FLOW model is developed for Wax Lake Delta, an actively prograding delta in southeastern Louisiana, in order to simulate daily and seasonal changes in water temperature and residence time within different hydrogeomoprhic zones of coastal deltaic floodplains. From January to March 2015, intertidal floodplains have warmer temperatures and longer residence times (up to 2.5 days) than subtidal floodplains (up to 1.5 days). However, when river discharge increases during spring floods, connectivity between channels and floodplains increases and residence times within all zones decreases as water is flushed more quickly to the Gulf of Mexico. Correctly simulating residence time of water within floodplains is essential to future efforts to model the transformation of nitrate in these systems.

<p> Low groundwater pH is frequently cited as inhibiting the performance of in-situ bioremediation of chlorinated solvents at contaminated sites. A common method of pH control is injection of solutions containing alkalinity, but alternatives for prolonged, passive pH control are needed. This work explores pH-responsive hydrogel coatings on MgO nanoparticles as vehicles for controlled release of alkalinity. Chitosan cross-linked with glutaraldehyde was evaluated as a representative hydrogel coating. The effects of coating thickness and cross-linking on the rate of alkalinity release were experimentally evaluated using batch dissolution experiments. Dissolution rates were found to be up to an order of magnitude slower for coated particles than for uncoated particles. A diffusion model was developed for the dissolution rate of coated particles, and the model was able to account for the dissolution rate as a function of coating thickness over a range of pH.</p>