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Micro Characterization Of Deformations In Granular Materials During Shear, Alsidqi Hasan
Micro Characterization Of Deformations In Granular Materials During Shear, Alsidqi Hasan
LSU Doctoral Dissertations
One of the greatest challenges in studying the engineering behavior of granular materials is the lack of tools for an unobstructed view of a large quantity of microscopic particles. This dissertation presents a thorough characterization of deformations in sheared granular materials. The investigation involves experimental programs, utilization of computed tomography (CT) techniques, and application of Distinct Element Method (DEM). The investigation was conducted at multi-scale (macroscopic, mesoscopic, and microscopic) to better understand the physical properties and constitutive behavior of granular materials during shear. The experiments include conducting a series of axisymmetric triaxial, miniature axisymmetric triaxial, and biaxial experiments. They were …
Nanoidentation Behavior Of Clay Minerals And Clay-Based Nonstructured Multilayers, Zhongxin Wei
Nanoidentation Behavior Of Clay Minerals And Clay-Based Nonstructured Multilayers, Zhongxin Wei
LSU Doctoral Dissertations
Clay minerals, ubiquitous in the geosphere, are hydrous layered silicates or phyllosilicates that are made of nanometer-thick 2:1 or 1:1 layers. Understanding their mechanical properties of clay minerals is of vital importance to a variety of disciplines, such as geomechanics, geophysics, mineral physics, and nanocomposites. Owing to their complex crystal structure and size, however, accurate determination of their mechanical properties is a significant challenge. This dissertation presents the first research effort to study systematically the fundamental mechanical properties along the c-axis (e.g., elastic modulus, hardness) of a wide range of phyllosilicates with varying crystal structure and chemical compositions. To explore …
Pore-Scale Analysis Of Dnapl Dissolution And Biomass Distribution, Keegan L. Roberts
Pore-Scale Analysis Of Dnapl Dissolution And Biomass Distribution, Keegan L. Roberts
LSU Doctoral Dissertations
A comparison of equilibrium and non-equilibrium dissolution of tetrachloroethylene (PCE) was conducted to ascertain how PCE saturation, individual blob properties (volume, surface area, sphericity), and PCE occupied pores are affected by two distinct dissolution regimes. One-dimensional columns were imaged at various dissolution stages using high resolution (~10 um) synchrotron x-ray tomography (XT) and image subvolumes were analyzed using a series of grain, pore network structure, and blob analysis algorithms. An analysis of algorithm-generated data was conducted to determine grain and pore statistics, PCE saturation and individual blob properties, and correlations between PCE blobs and pore network structure. Grain and pore …
An Uncertainty-Based Approach To The Total Maximum Daily Load Development, Abhijit Patil
An Uncertainty-Based Approach To The Total Maximum Daily Load Development, Abhijit Patil
LSU Doctoral Dissertations
A Bayesian-updating approach is developed to the estimation of the total uncertainty-based Margin of Safety (MOS) for Total Maximum Daily Load calculations using the watershed modeling tool HSPF. In order to determine the prior, likelihood, and posterior distributions of uncertainties involved in Bayesian approach, various probability density functions are derived. The temperature measurement induced uncertainty in dissolved oxygen simulation is found to be normally distributed. The temporal scale uncertainty in weather data decreases with decreasing temporal resolution. The temporal-scale uncertainties in the rainfall and temperature data follow a Weibull and general extreme value distributions, respectively. The spatial-resolution uncertainty in simulated …
Slab-On-Girder Prestressed Concrete Bridges: Linear And Nonlinear Finite Element Analysis And Experimental Load Tests, Marcio Costa Araujo
Slab-On-Girder Prestressed Concrete Bridges: Linear And Nonlinear Finite Element Analysis And Experimental Load Tests, Marcio Costa Araujo
LSU Doctoral Dissertations
“A diaphragm is a transverse stiffener, which is placed between girders in order to maintain section geometry”, (AASHTO, 2002). Intermediate diaphragms, usually placed at the midspan or third points of a bridge, are thought to contribute to the overall distribution of live loads in bridges. Cast-in-place concrete intermediate diaphragms were investigated in this study in order to assess their load distribution effectiveness in prestressed concrete I-girder bridges. Finite element packages (Ansys and GT STRUDL) were used to perform the analyses for multiple bridge configurations, including a parametric study of span length, girder spacing, and concrete strength. It was found that …
Stability Of Articulated Revetments Against Wave Attack On Shallow Soft Soil Slopes, Edmond Joseph Russo
Stability Of Articulated Revetments Against Wave Attack On Shallow Soft Soil Slopes, Edmond Joseph Russo
LSU Doctoral Dissertations
Continuously-connected, articulated revetment systems have potential to decrease the weight of armor cover in resisting wave attack, compared to traditional designs. Modes of instability for sloping revetments include uplift, sliding, and toe roll-up. Design methods are summarized by McDonnell (1998), Pilarczyk (1998), and Herbich (1999). Russo (2003) conducted a field prototype scale investigation on performance of Articulated Concrete Mattresses (ACMs) in coastal Louisiana, which demonstrated this structure’s ability to resist a range of wave loading conditions, and inspired scoping of further research to quantify structure performance beyond known limits. Present research expanded earlier works by examining fundamental physical processes of …
The Fate And Transport Of Light Petroleum Hydrocarbons In The Lower Mississippi River Delta, Samantha Nicole Danchuk
The Fate And Transport Of Light Petroleum Hydrocarbons In The Lower Mississippi River Delta, Samantha Nicole Danchuk
LSU Doctoral Dissertations
Important processes governing the fate and transport of light petroleum hydrocarbons in the Lower Mississippi River and other river delta systems are not adequately represented in existing oil spill models. In response, three methods were introduced to include the effects of dynamic annual discharges and variation of shoreline type on shoreline retention and re-floatation and the potential of oil- mineral aggregate formation based contributing environmental factors. Parcel tracking was used, in conjunction with detailed shoreline types correlated to flow rate, to evaluate the benefits of using multiple shoreline re-floatation half lives correlated to shoreline type instead of a single half …
System Identification Of Bridge And Vehicle Based On Their Coupled Vibration, Lu Deng
System Identification Of Bridge And Vehicle Based On Their Coupled Vibration, Lu Deng
LSU Doctoral Dissertations
Most current techniques used for system identification of bridges and vehicles are static-test-based methods. Methodologies that can use bridge dynamic responses or modal information are highly desirable and under development. This dissertation aims to develop new identification methodologies for bridge-vehicle systems using the bridge dynamic responses and modal information. A new bridge model updating method using the response surface method (RSM) was proposed in this dissertation. The RSM was used to design experiments in order to find out the relationships between the bridge responses and parameters to be updated. Results from numerical simulations and a field study show that the …
Hearing Assessment Of Forest Loggers, Antonio A. Fonseca
Hearing Assessment Of Forest Loggers, Antonio A. Fonseca
LSU Master's Theses
Forest logging is the process in which trees are cut down for forest management and/or timber harvest. According to OSHA, logging is the most dangerous occupation in the United States. It consistently represents one of the most hazardous industries, with a fatality rate more than 21 times higher than the rate for all workers in the United States. Yet, little research has been performed to determine the long term effect of noise on forest loggers. OSHA regulations state that the maximum permissible hearing in an 8 hour shift should not exceed 90 dB. Occupational noise exposure is recognized as a …
Dynamic Behavior Of Unsaturated Soils, Prathima Alla
Dynamic Behavior Of Unsaturated Soils, Prathima Alla
LSU Master's Theses
The behavior of unsaturated soils is different from the behavior of saturated soil deposits. Unsaturated soils have more than two phases; the pore water pressure in unsaturated soils is negative. The behavior of unsaturated soil when a dynamic loading such as an earthquake loading is imposed on them, the susceptibility of lab tested soils to liquefaction is investigated in this study. As the phenomenon of liquefaction occurs only in the case of saturated soil deposits, the behavior of unsaturated soil under these conditions is investigated. Sand and silty sand are used in this study, wetting and drying soil water characteristic …
The Study Of Sediment Dynamics In A Shallow Estuary Using Integrated Numerical Modeling And Satellite Remote Sensing, Haihong Zhao
The Study Of Sediment Dynamics In A Shallow Estuary Using Integrated Numerical Modeling And Satellite Remote Sensing, Haihong Zhao
LSU Doctoral Dissertations
The primary objective of the study is to develop an effective tool to investigate the resuspension, deposition and transport of mixed cohesive and non-cohesive sediments in an estuary. The research has integrated 1) statistical analyses of the primary forcing, 2) numerical models for hydrodynamics, surface waves and sediment transport, and 3) the MODIS (Moderate Imaging Spectroradiometer) remotely sensed imagery, to investigate hydrodynamics and sediment dynamics in Mobile Bay, Alabama. First, based on long-term meteorological and tidal observations, statistical analyses have been conducted to predict extreme values of winds and water levels at different return periods in the estuary. Application of …
Assessing The Accuracy Of Task Time Prediction Of An Emerging Human Performance Modeling Software - Cogtool, Oluwakemi Damilola Adio
Assessing The Accuracy Of Task Time Prediction Of An Emerging Human Performance Modeling Software - Cogtool, Oluwakemi Damilola Adio
LSU Master's Theses
There is a need for a human performance modeling tool which not only has the ability to accurately estimate skilled user task time for any interface design, but can be used by modelers with little or no programming knowledge and at a minimal cost. To fulfill this need, this research investigated the accuracy of task time prediction of a modeling tool – CogTool - on two versions of an interface design used extensively in the petrochemical industry – DeltaV. CogTool uses the KeyStroke Level Model (KLM) to calculate and generate time predictions based on specified operators. The data collected from …
Hydro Mechanical Behavior Of Unsaturated Soil Subjected To Drying, Dev Raj Pokhrel
Hydro Mechanical Behavior Of Unsaturated Soil Subjected To Drying, Dev Raj Pokhrel
LSU Master's Theses
The literature of unsaturated soils in terms of hydraulic and mechanical behavior is reviewed. The hydro- mechanical behavior of unsaturated soil was studied using experimental investigation and numerical simulation of 1D and 2D modeling in HYDRUS software. Low plasticity silty clay (CL) and sand bentonite mixed soil SB (5% and 2% bentonite) specimens were investigated. Soil water characteristics curve (SWCC) tests were carried out in CL sample along with shear wave velocity measurement test using bender element (BE). The influence of moisture variation on specimens was investigated to see its impact on suction and on stiffness of soil. Similarly, the …
Effects Of Physical And Mental Tasks On Heart Rate Variability, Satya Anasuya Paritala
Effects Of Physical And Mental Tasks On Heart Rate Variability, Satya Anasuya Paritala
LSU Master's Theses
Demands at work are associated with an increased risk of cardio vascular diseases, but little is known about its underlying connection. The purpose of this study was to evaluate the effects of physical and mental tasks that induced stress, on Heart Rate Variability (HRV). Another aim was to observe the trends in subjective workload ratings in conjunction with the physiological response of the heart and also to assess the comfort level of the participants while wearing the heart rate monitor and performing tasks. Heart rate was recorded while at rest and while performing the tasks. Subjective workload ratings were obtained …
Passenger Car Equivalents Of Trucks Under Lane Restriction And Differential Speed Limit Policies On Four Lane Freeways, John Stanley
Passenger Car Equivalents Of Trucks Under Lane Restriction And Differential Speed Limit Policies On Four Lane Freeways, John Stanley
LSU Master's Theses
Lane restriction for trucks and differential speed limits for trucks and cars are becoming more common and feasible policies to improve the efficiency and safety of a freeway. It is believed that passenger car equivalents for trucks are impacted by these non typical freeway operating conditions, which are not explicitly addressed by the latest edition of the Highway Capacity Manual. Using simulated and real world data an elevated 18- mile four lane freeway was modeled under the restriction policies. The section which was used as a test bed was simulated under various control variables. Some of the control variables used …
Impact Of Watershed Delineation Detail On Hydrologic Process Modeling In Low Slope Areas, Jason Alexander Braud
Impact Of Watershed Delineation Detail On Hydrologic Process Modeling In Low Slope Areas, Jason Alexander Braud
LSU Master's Theses
Ascension Parish, located along the Mississippi River in southern Louisiana, is a low-lying, low slope landscape that primarily drains into the tidally-influenced Lake Maurepas. The predominant method of drainage within the parish is gravity drainage. Ascension Parish is currently one of the fastest growing areas in the United States. New developments have changed the area’s hydrology along with its landscape. Proper watershed delineation within the parish is critical for the management of and future improvements to the parish’s drainage infrastructure. Most of the recent drainage modeling in the parish has been performed using a light detection and ranging (LIDAR) digital …
Freeway Crash And Lane Compliance Under Truck Lane Restriction And Differential Speed Limit, Murat Korkut
Freeway Crash And Lane Compliance Under Truck Lane Restriction And Differential Speed Limit, Murat Korkut
LSU Master's Theses
In the last decade, several fatal truck related crashes occurred on the elevated freeway over the Atchafalaya Basin. In an attempt to reduce the crash rates, the Louisiana Department of Transportation and Development implemented two policies to regulate the truck traffic on this rural divided freeway that has two lanes in each direction of flow. These policies restricted truck traffic to the right lane and reduced the maximum truck speed limit to 55-mph. On the other hand, maximum car speed limit was kept at 60-mph. The changes took place in 2003. While the policies were in effect, crash and traffic …
Laser Assisted Friction Stir Welding: Finite Volume Method And Metaheuristic Optimization, Shivani Daftardar
Laser Assisted Friction Stir Welding: Finite Volume Method And Metaheuristic Optimization, Shivani Daftardar
LSU Master's Theses
Friction Stir Welding (FSW) is a solid state joining process that uses a non-consumable rotating welding tool to generate frictional heat at the welding location. Large forces are required to produce friction between the welding tool and the work piece which increases the wear rate of the welding tool in welding materials with high melting temperature. Several different approaches have been developed to address this problem. This thesis focuses on a new modification of friction stir welding, called Laser Assisted Friction Stir Welding, a process developed in the last decade. This process uses laser energy to preheat the work piece …
Prioritization Of Safety Countermeasures For The State Of Louisiana Using Fuzzy Inference Systems, Meisam Akbarzadeh
Prioritization Of Safety Countermeasures For The State Of Louisiana Using Fuzzy Inference Systems, Meisam Akbarzadeh
LSU Master's Theses
In this study a fuzzy inference system is proposed for prioritization of countermeasures aimed at improving safety in the state of Louisiana. Countermeasures are prioritized based on their collective performance on cost, expected crash reduction and the severity of the problem they address. These three decision parameters can have six permutations in terms of their relative importance in decision making. In order to make the prioritization procedure handier for decision makers, the inference system is capable of being run under all six possible cases. Current safety standards influence the importance attached to crash reduction performance and severity of the problem …
Gas Transfer In Air-Lifts Used To Recirculate Aquaculture Systems, Ryan Anthony Hearn
Gas Transfer In Air-Lifts Used To Recirculate Aquaculture Systems, Ryan Anthony Hearn
LSU Master's Theses
The following studies were conducted to determine hydraulic, aeration, and degasification characteristics associated with various air-lift pumps. The first study presented data on a 20.3 cm air-lift used to support adult Yellowtail broodstock (Seriola lalandi) in an oligotrophic warmwater marine RAS (recirculating aquaculture system). Empirical relationships were used to estimate actual oxygen and carbon dioxide mass transfer rates (AOTR & ACTR) as the inlet oxygen or carbon dioxide concentrations were perturbed under lift heights of 30.5, 38.1, and 45.7 cm. Transfer rates, kg of constituent per day, were found to be dependent on air injection depth and volume, aqueous gas …
Neck Muscles Activity And Upper Body Extremity Angles In Dynamic Overhead Lifting, Mohamed Wassim Mokrani
Neck Muscles Activity And Upper Body Extremity Angles In Dynamic Overhead Lifting, Mohamed Wassim Mokrani
LSU Master's Theses
Injuries of the neck and shoulders are common among workers who perform overhead tasks. In order to develop an injury-free working environment with regards to occupational musculoskeletal stress, it is pivotal to understand the pathophysiology of mechanical stress on the musculoskeletal system. The objective of this research was to study the effect of overhead lifting on the sternocleidomastoid and upper Trapezius muscles. Upper body joint angles were also analyzed using APAS during the overhead lifting. This study was conducted using two devices. The set of equipment incorporates an electromyography device, and the APAS. Two electrodes were placed at the muscle …
Thermomechanical Modeling And Optimization Of Friction Stir Welding, Manthan Malde
Thermomechanical Modeling And Optimization Of Friction Stir Welding, Manthan Malde
LSU Master's Theses
This thesis research implemented an existing thermomechanical model of friction stir welding process, and studied the surrogate model-based optimization approach to obtain optimal process parameters for the modeled friction stir welding process. As an initial step, the thermomechanical model developed by Zhu and Chao for friction stir welding of 304L stainless steel was replicated using ANSYS. The developed model was then used to conduct parametric studies to understand the effect of various input parameters like total rate of heat input, welding speed and clamping location on temperature distribution and residual stress in the workpiece. With the data from the simulated …
A Decision Making Framework For Hurricane Evacuation And Sheltering, Jason Fennell
A Decision Making Framework For Hurricane Evacuation And Sheltering, Jason Fennell
LSU Master's Theses
There are few tools currently available to emergency managers to assist in making decisions about whether to evacuate, shelter locally, or shelter-in-place, and none of these tools explicitly consider risk to life safety. A methodology was developed to provide risk-based guidance for evacuation versus sheltering decision making. The hurricane hazards considered in the developed methodology are high winds, storm surge flooding and waves, and rainfall flooding. Vulnerability of buildings to these hazards and the associated risks to life safety are then determined. These results are compared to the hazards and risks associated with evacuation, particularly for medical special needs populations …
Granular Activated Carbon Sorption As A Load Equalization Mechanism In Operation Of Air Pollution Control Devices, Marilou Montevirgen Nabatilan
Granular Activated Carbon Sorption As A Load Equalization Mechanism In Operation Of Air Pollution Control Devices, Marilou Montevirgen Nabatilan
LSU Doctoral Dissertations
Transient periods of unsteady loading pose a challenge in design and operation of bioreactors for air pollution control. As a potential means of overcoming some of these challenges, a systematic study of granular activated carbon (GAC) sorption was conducted to further evaluate its potential as a load equalization mechanism for unsteady loading of volatile organic carbons (VOCs). GAC columns were experimentally tested under dynamic loading conditions involving variations in contaminant concentrations, gas flow rates, and relative humidity. Toluene was used as model VOC, and BPL 4x6 mesh GAC was used as a model adsorbent. The research was divided into four …
Fundamental Characterization Of Unbound Base Course Materials Under Cyclic Loading, Aaron Matthew Austin
Fundamental Characterization Of Unbound Base Course Materials Under Cyclic Loading, Aaron Matthew Austin
LSU Master's Theses
ABSTRACT Pavements are a layered system each layer distinguished by different materials as required by traffic and subgrade conditions. A base course is an intermediate layer constructed of high quality stone aggregates: quality based on physical properties such as gradation, hardness, and texture. Although indicative of performance, physical properties do not directly measure performance. This thesis presents the results of a comprehensive experimental testing program that was conducted to examine the behavior of unbound granular base materials under cyclic loading and to evaluate the effect of the stress level and moisture content on strain behavior. Three base materials, namely granite, …
Development And Operational Analysis Of Highway Alternating Merge Transition Zones, Wakeel Ishola, Anthony Idewu
Development And Operational Analysis Of Highway Alternating Merge Transition Zones, Wakeel Ishola, Anthony Idewu
LSU Doctoral Dissertations
The design and control of work zone traffic control areas is governed by standards published by the United States Department of Transportation (US-DOT) and documented in the Manual for Uniform Control Devices (MUTCD). While these configurations have evolved over time to reflect safer and more efficient management practices and have become familiar to drivers, they are also recognized as areas of vehicle conflict that can cause congestion and safety problems. As part of this research, a new design has been developed that has the potential to lessen the detrimental effects of lane closures in work zones. This new concept, known …
Residential Building Damage From Hurricane Storm Surge: Proposed Methodologies To Describe, Assess And Model Building Damage, Carol J. Friedland
Residential Building Damage From Hurricane Storm Surge: Proposed Methodologies To Describe, Assess And Model Building Damage, Carol J. Friedland
LSU Doctoral Dissertations
Although hydrodynamic models are used extensively to quantify the physical hazard of hurricane storm surge, the connection between the physical hazard and its effects on the built environment has not been well addressed. The focus of this dissertation research is the improvement of our understanding of the interaction of hurricane storm surge with the built environment. This is accomplished through proposed methodologies to describe, assess and model residential building damage from hurricane storm surge. Current methods to describe damage from hurricane events rely on the initiating mechanism. To describe hurricane damage to residential buildings, a combined wind and flood damage …
Phosphorus Dynamics In The Marshland Upwelling System, Dhaval Shirish Shah
Phosphorus Dynamics In The Marshland Upwelling System, Dhaval Shirish Shah
LSU Master's Theses
The Marshland Upwelling System (MUS) is an alternative onsite wastewater treatment technology designed to utilize the natural ecology of saltwater marshes to remove human-borne contaminants. Previous research has assessed the ability of MUS to remove both total and orthophosphate. Studies have also indicated a clear zone of phosphorus (P) saturation occurring in MUS soils. Laboratory column study was performed to accomplish the objectives of this study which were to: 1) determine the fate and fractionation of phosphorus in the soil matrix, 2) understand sorption kinetics and determine phosphorus sorption potential of wetland soils in retaining phosphorus in the MUS, 3) …
Numerical Modeling For Long Term Performance Of Soil-Bentonite Cut-Off Walls In Unsaturated Soil Zone, Sukanta Chakraborty
Numerical Modeling For Long Term Performance Of Soil-Bentonite Cut-Off Walls In Unsaturated Soil Zone, Sukanta Chakraborty
LSU Master's Theses
ABSTRACT The construction practices of containment walls are extremely important in this competitive economic market, but development is limited. Unsaturated zone is an integral part of the geotechnical problems, as it affects on any kind of soils structures. The unsaturated zone plays significant role in many aspects of water flow and contaminant transport, including containment system such as: cut-off walls, infiltration, soil moisture storage, evaporation, plant water uptake, ground water recharge, erosion, and runoff. This research focuses on the hydraulic sustainability and performance of soil-bentonite cutoff walls (Britton et al, 2004) models showing hydraulic behavior of barrier walls. The cutoff …
Laboratory Characterization Of Geogrid-Reinforced Unbound Granular Material For Use In Flexible Pavement Structures, Gael Souci
LSU Master's Theses
This thesis documents and summarizes research and background information carried on geogrid reinforced base course in pavement design. Research was experimental carried through Repeated Load Triaxial (RLT) tests at the Louisiana Transportation Research Center. The experimental tests were performed to observe the benefit of the geogrid as well as to differentiate between geogrid location, geometry and tensile modulus of the various geogrid. Experiments were also carried to further describe the Shakedown Theory and its use for characterization of base course materials. The experimental results showed that there was a benefit in placing the geogrid within the aggregate specimen. There were …