Finite element solution in the updated Lagrangian frame is used to investigate the strain localization phenomenon "shear bands" in granular materials. The micro-polar theory was used as the mathematical foundation for the continuum formulations. A laboratory testing results are used for verification and comparison with the numerical simulation. Silica sand and glass beads with different shape indices, size and surface roughness were tested under biaxial and triaxial loading conditions to investigate the physics of the problem. The shape non-uniformity and the irregular surface roughness of the grains were studied carefully to evaluate their effect on shear band characteristics. To this end, attempts have been made to bring these additional micro-properties into the constitutive equations in this study. Elasto-plastic constitutive laws with a non-associated flow rule were used in order to capture the high deformations inside the localization zones. The Micropolar theory requires two independent kinematical fields; the first is the Cosserat objective strain tensor and the second is the curvature or the rotation gradient vector. The deviation in the kinematics is performed using the classical continuum with the incorporation of the couple stress effect. A single hardening yielding model, (Lade's model), with a different plastic potential function has been enhanced to account for the couple stresses and the rotations of the grains through the stress invariants. Finally, the finite element formulations in the updated Lagrangian frame were obtained. These formulations have been implemented into the finite element program ABAQUS using the user element subroutine utility (UEL). The study findings were consistent with the experimental results and the physical understanding of the phenomenon. The surface roughness of the particles was found to affect the shear band thickness and present model was able to feel such effects. The shape of the particles was found to significantly affect the shear band thickness as well. The effect of the initial void ratio, confining pressure, particle size, surface roughness and shape of particles is discussed in this dissertation. At the end, the material properties spatial distribution was mapped into the finite element mesh and the material heterogeneity effect on strain localization is shown accordingly.

Metal species infused particulate matter associated with urban rainfall-runoff is a unique and profuse source of pollution. Generated from urban activities, such as traffic activity and vehicular/infrastructure abrasion, contaminated residual material is deposited to roadways during dry weather and transported to surrounding environments and/or best management practice (BMP) treatment facilities during wet-weather events. These particulates range in size from 1 Ým to 10000 Ým and are contaminated with metal species that originate from such sources as vehicular body wear (Cu), tire wear (Zn), and brake dust (Pb). Depending on the efficiencies of the BMP treatment facilities, these containment systems have the potential to be an abundant source of solid and potentially hazardous waste. Rainfall-runoff residual matter was collected from five urban BMP sites and characterized for granulometric indices. The sites were located in Baton Rouge, LA, Little Rock, AR, North Little Rock, AR, and Cincinnati, OH. The residual matter collected from the five BMP sites was characterized as a function of particle size for particle mass, particle size distribution (PSD), particle density (âs), total surface area (SA), specific surface area (SSA), and metal species contamination. This characterization study showed that the majority of the metal species mass contamination is associated with the coarse to mid-sized range of particles with large amounts of SA, while the predominance of metal species concentration contamination is found in the fine particulates with high SSA. Cement-based solidification/stabilization (S/S) was applied to residual matter recovered from the BMP facility located in Baton Rouge, LA, using three cement types. Cement-based S/S has been used in the treatment of a wide range of metal contaminated wastes, but there is no record of the technology being applied to rainfall-runoff residuals. Three gradations (total (entire gradation), coarse (> 75 Ým), and fine (< 75 Ým)) of rainfall-runoff residuals were treated using a type I portland cement (PC), a slag cement (SC), and a 1:1 mass ratio of type I portland cement and slag cement (PS). An assessment of the solidification of the treated residuals was made using techniques to analyze the hydration behavior and physical strength and the leaching potential of the untreated and treated residuals was assessed in order to determine the stabilization effectiveness of the S/S application to the rainfall-runoff residuals.

Rainfall-runoff quantity and quality control presents unique challenges due to the complexity and variability of hydrology and rainfall-runoff chemistry as well as the variable nature of constituent-producing processes in the environment. This study investigates two fundamental processes in rainfall-runoff: temporal particle agglomeration and metal partitioning between the solid and aqueous phase. A series of rainfall-runoff events were captured at an urban, Portland concrete cement (PCC) paved site in Baton Rouge, Louisiana and characterized with respect to particle gradation and metal phase fractions (dissolved and particulate) over time from a well-mixed, batch experimental system. Results indicate that equilibria and kinetics of natural particle agglomeration are inversely related to rainfall-runoff volume pH. Further, the average velocity gradient induced on a fully mixed system aids in particle agglomeration by entraining a larger fraction of the total particle gradation for particle-to-particle interaction. Following rainfall-runoff volume phase fractionation and ICP-MS analysis, metal partitioning was found to be in operational equilibrium at the naturally-occurring pH at the point of sample capture at the urban Baton Rouge site. Rainfall-runoff partitioning was compared between similar transportation land use sites in Baton Rouge, LA (544-m² of PCC pavement) and Cincinnati, Ohio (300-m² of asphalt pavement). Results suggest that the nature of the roadway material at Baton Rouge and elevated dissolved hardness cause both the state of equilibrium partitioning as well as a higher degree of particulate-bound partitioning. Partitioning is significantly particulate-bound for Cu, Zn, and Cd at the Baton Rouge site with arithmetic mean fp values of 0.72, 0.64, and 0.97, respectively as compared to fp values at the Cincinnati site of 0.04, 0.04, and 0.29 for these metals. While Pb was mostly particulate-bound for both the Baton Rouge and Cincinnati sites, the metal is significantly more particulate-bound at the Baton Rouge site with an fp value of 0.98 as compared to 0.68 for Cincinnati.

4-inch cubical sand specimens were been tested under drained conditions using a wide range of stress paths. The testing was performed by means of a true (cubical) triaxial device that has been conditioned for this study. This testing set-up consisted of a servo-controlled, single-boundary type apparatus, with six flexible membranes that create a center cavity surrounding the soil specimens. This thesis illustrates the functioning of the triaxial device, including detailed descriptions of the device components, sample preparation, and a practical application related to the mechanical characterization of granular materials using critical state soil mechanics. An experimental program, based on the above-described testing device, was created and implemented in order to calibrate a simple constitutive model (Cam Clay Model), and to compare the predictions of this model with the observed mechanical behavior of the selected material under triaxial state of stress. The results of the testing program for this study are typically presented in the Deviatoric Stress vs. Shear Strain Plane, and in the Triaxial Space. These results indicated that the testing program implemented for the calibration of the Cam Clay Model was successful in reproducing the general mechanical behavior of the granular material tested herein. General conclusions and recommendations for further research are included in at the end of this paper.

The deformation and strength behavior of dry and saturated soils is controlled by the effective stresses as defined by Terzaghi. However, Terzaghis definition of the effective stresses fails for unsaturated soils, as capillarity force influence is also important. The effects of capillarity forces in soil are evaluated by the concept of matrix suction. Several techniques are used to evaluate soil suction however their applications involve difficult calibrations and tedious methodology. Furthermore, suction is a microscopic property and it is influenced by interparticle soil attraction, which can change by sampling disturbance. This research program evaluates the effect of suction on stiffness and strength of soils at small strain (at constant fabric) and large strain (with fabric changes) levels. The phenomena are studied using a modified oedometer cell and a multi-axial device with matric suction control that have been equipped with bender elements for shear-wave velocity measurements. The test program consists on testing dry and unsaturated specimens under different boundary conditions: Ko-loading and multi-axial loading. To test the Ko-loading condition, the soil is loaded in the oedometer cell while the bender-elements monitor the changes in state of stresses by evaluating the changes in the velocity of wave propagation. Similarly, triaxial compression and conventional triaxial compression tests, along with monitoring of shear wave velocities, are conducted on 10-cm side cubical specimens of reconstituted soil specimens to study the stress-strain behavior of an unsaturated soil over a range of degrees of suctions and stress paths and the effect they have on the propagation velocity of shear waves. Results show the adequacy of methods and equipment used in this investigation to monitor the behavior of unsaturated soils under the application of a range of suctions and several stress paths. Experimental results are analyzed using simple, yet robust wave propagation models and geo-material behavior. Their interpretation bring a better understanding to low and large strain-stress behavior of near sub-surface soils. Results provide a stronger base for the development of models for the imaging of near-surface geo-materials using elastic wave-based imaging techniques and for better interpretation of geotechnical models of design.

Global warming is the most important issue of the present day that affects the climate drastically. This research was carried out to find out the effects of Global warming on Louisiana in future on a very finer spatial and temporal scale. For this purpose spatial downscaling technique is used, where finer resolution climate information is derived from a coarser resolution Global Climate Model (GCM) output. Empirical/statistical downscaling method is used in which sub grid scale changes are calculated as a function of large scale climate. For this purpose a stochastic weather generator and two Global models are considered. The two global models are CCCma (Canadian Center for Climate Modeling and Analysis) and CSIRO (Australia's Commonwealth Scientific and Industrial Research Organization). The stochastic weather generator used is Climate Generator (CLIGEN). The global monthly means are calculated until the year 2090 from the available daily data of CCCma and CSIRO and the units are converted according to that used in CLIGEN. The monthly means of the parameter files of CLIGEN are replaced with the Global monthly means, and the other statistical parameters such as standard deviation, skewness, etc are changed accordingly and weather is generated using the CLIGEN until the year 2090 for Louisiana. Statistical analysis is performed for the climate generated using the two Global models and comparisons are made between the results of the two models. Also time series plots are drawn for the generated climate of the two models taking one year as a representative year.

The Anacostia Active Capping Project (AACP) is a United States Environmental Protection Agency (EPA) funded initiative to develop and implement, on a field scale, active capping barrier technologies. Overseen by the Hazardous Substance Research Center, South and Southwest (HSRC), the AACP plans to demonstrate the ability of active capping barrier technologies to prevent the migration of contaminants from the sediment bed to the overlying water column of the Anacostia River. The demonstration project will involve the placement and monitoring of four individual types of capping materials (apatite, Aquablok, coke breeze, and sand) and the monitoring of one control (i.e. uncapped) area. An integral part of this capping/monitoring effort will be the use of the Model for the Assessment and Remediation of Sediments (MARS) to project long term cap stability and effectiveness. Developed by the Electric Power Research Institute (EPRI), MARS allows for the modeling of river hydrodynamics, sediment transport, chemical fate/transport, and contaminated sediment remediation with one stand-alone model. It is the object of this research to not only model river characteristics and cap effectiveness but to also identify those areas of the MARS model which could benefit from revisions to allow for future active capping barrier simulations. Model projections illustrate the demonstration area as being a zone of sediment deposition during normal flow events. Furthermore, MARS predicts Aquablok and coke breeze as being the most effective capping barriers when considering PAH migration from the sediment column to the overlying water body. Apatite displayed little PAH contaminant retardation as this barrier is being implemented in the AACP in an attempt to precipitate heavy metals from the sediment and pore water.

The marshland upwelling system (MUS) was installed in a floatation marsh along the banks of the Bayou Segnette Waterway, Louisiana. This site was characterized by native groundwater of low salinity regime. Previous studies focused on the removal of fecal pathogens from settled/raw and secondarily treated wastewater under high saline groundwater conditions. The objectives of this research were to: 1) quantify the impact of natural die-off on bacterial removal within the MUS, 2) determine bacterial retardation rates in laboratory-repacked sandy loam soil columns, and 3) evaluate the effectiveness of the MUS in removing fecal pathogens from settled, raw wastewater. Varying salinities and temperatures were used to investigate the inactivation rates for fecal coliforms. Rapid inactivation was recorded for each temperature studied, followed by a much slower die-off process. The higher temperature (25°C) was more detrimental to fecal coliform survival than the 20°C study. Increasing salinity concentrations was not detrimental to fecal coliform survival. Continuous injection experiments performed in one-dimensional columns packed with sandy loam soils from the field recorded bacterial retardation factors of between 4.7 and 7.7 with respect to the conservative wastewater tracer. Higher limitations to bacterial transport are expected under field-scale conditions. The MUS was evaluated under three separate injection schemes: a high flow/low temperature loading (HFLT), a 0.95 L/min and a 1.9L/min studies injecting for 15 minutes every hour. The 0.95 L/min flowrate was most suited for bacterial removal. The injection depth employed impacted fecal coliform removal rates. Mean influent concentrations of 92,510±489,614 MPN/100mL were reduced to effluent concentrations of 4.0±7.6 MPN/100mL (observed in the 2.7 m wells). Four-log reductions in influent concentrations were observed within a one-meter radial distance from the injection point. Overall removal followed a first-order decay relationship with respect to vector distance. Removal rate constants for fecal coliforms ranged from 2.0 -4.0 m^-1, and that for E. coli ranged from 1.7-4.0 m^-1.

The dynamically varying concentrations of volatile organic compounds (VOCs) in most waste gas streams present a challenge in design and operation of biofilters treating such off-gases. Studies described in this dissertation were directed toward development and experimental testing of two design modifications/operating strategies that have the potential to improve biofilter performance during unsteady-state loadings. In the first design modification studied, activated carbon was incorporated into biofilter packing media and a novel periodic operating strategy, Sequencing Batch Biofilter (SBB) operation, was tested under normal and various shock loading conditions treating methyl ethyl ketone contaminated air. Results demonstrate how the operational flexibility of the SBB system can lead to higher overall removal efficiency and higher minimum instantaneous removal efficiency than are achieved in a conventional continuous flow biofilter (CFB) during transient loading. Denaturing gradient gel electrophoresis of PCR-amplified genes coding for 16S rRNA was used to assess differences in bacterial community structure as a function of height in the SBB and CFB columns. Results suggest that SBB operating strategy can impart a sufficiently large selective pressure to influence microbial community structures. In the second design modification studied, an activated carbon column was placed in series before a biofilter to assess the potential of the combined system to effectively treat discontinuously loaded VOC mixtures. Abiotic fixed-bed sorption experiments and numerical modeling were conducted to assess the degree of load equalization achieved by GAC columns for gas streams containing intermittent concentrations of acetone and toluene present as single-component contaminants and as a mixture. Performance of the GAC-biofilter integrated system was experimentally evaluated in comparison to a conventional biofilter in treating a mixture of acetone and toluene at various discontinuous loadings. Results demonstrate that load dampening achieved by a passively-operated GAC buffering system can lead to more complete contaminant removal during biofilter treatment. Further, this can minimize diminished performance caused by starvation encountered in conventional biofilters under discontinuous loadings. Because of competitive adsorption, however, the degree of load equalization achieved by a passively operated GAC system for different constituents in multi-contaminant gas streams can vary markedly.

In this study a gravity model was used to model destination choice during a hurricane evacuation. Hurricane Floyd data was used to calibrate and apply the gravity model. Two different models were generated for different destination types; home of friends/relative and hotels and motels are the two different destination types for which the models were generated. The performance of the gravity model was tested by comparing the observed and estimated OD matrices using the chi-squared test. The results have indicated that gravity model developed in this study can successfully reproduce the observed trip destinations during a hurricane evacuation The Floyd model developed was then tested for transferability by applying the model on the Hurricane Andrew data. It was observed that the gravity model developed on Floyd data can be transferred and used on the Andrew data.