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Articles 841 - 870 of 1043

Full-Text Articles in Civil and Environmental Engineering

Neck Muscles Activity And Upper Body Extremity Angles In Dynamic Overhead Lifting, Mohamed Wassim Mokrani Jan 2009

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 …

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Prioritization Of Safety Countermeasures For The State Of Louisiana Using Fuzzy Inference Systems, Meisam Akbarzadeh Jan 2009

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 …

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Laser Assisted Friction Stir Welding: Finite Volume Method And Metaheuristic Optimization, Shivani Daftardar Jan 2009

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 …

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Hearing Assessment Of Forest Loggers, Antonio A. Fonseca Jan 2009

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 …

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Assessing The Accuracy Of Task Time Prediction Of An Emerging Human Performance Modeling Software - Cogtool, Oluwakemi Damilola Adio Jan 2009

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 …

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Phosphorus Dynamics In The Marshland Upwelling System, Dhaval Shirish Shah Jan 2009

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) …

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Hydro Mechanical Behavior Of Unsaturated Soil Subjected To Drying, Dev Raj Pokhrel Jan 2009

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 …

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Effects Of Physical And Mental Tasks On Heart Rate Variability, Satya Anasuya Paritala Jan 2009

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 …

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Passenger Car Equivalents Of Trucks Under Lane Restriction And Differential Speed Limit Policies On Four Lane Freeways, John Stanley Jan 2009

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 …

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Numerical Modeling For Long Term Performance Of Soil-Bentonite Cut-Off Walls In Unsaturated Soil Zone, Sukanta Chakraborty Jan 2009

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 …

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Dynamic Behavior Of Unsaturated Soils, Prathima Alla Jan 2009

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 …

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Fundamental Characterization Of Unbound Base Course Materials Under Cyclic Loading, Aaron Matthew Austin Jan 2009

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, …

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A Decision Making Framework For Hurricane Evacuation And Sheltering, Jason Fennell Jan 2009

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 …

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Development And Operational Analysis Of Highway Alternating Merge Transition Zones, Wakeel Ishola, Anthony Idewu Jan 2009

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 …

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Impact Of Watershed Delineation Detail On Hydrologic Process Modeling In Low Slope Areas, Jason Alexander Braud Jan 2009

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 …

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Freeway Crash And Lane Compliance Under Truck Lane Restriction And Differential Speed Limit, Murat Korkut Jan 2009

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 …

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Residential Building Damage From Hurricane Storm Surge: Proposed Methodologies To Describe, Assess And Model Building Damage, Carol J. Friedland Jan 2009

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 …

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System Identification Of Bridge And Vehicle Based On Their Coupled Vibration, Lu Deng Jan 2009

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 …

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The Fate And Transport Of Light Petroleum Hydrocarbons In The Lower Mississippi River Delta, Samantha Nicole Danchuk Jan 2009

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 …

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Copula-Based Multivariate Hydrologic Frequency Analysis, Hemant Chowdhary Jan 2009

Copula-Based Multivariate Hydrologic Frequency Analysis, Hemant Chowdhary

LSU Doctoral Dissertations

Multivariate frequency distributions are being increasingly recognized for their role in hydrological design and risk management. The conventional multivariate distributions are severely limited in that all constituent marginals have to be from the same distribution family. The copula method is a newly emerging approach for deriving multivariate distributions which overcomes this limitation. Use of copula method in hydrological applications has begun only recently and ascertaining the applicability of different copulas for combinations of various hydrological variables is currently an area of active research. Since there exists a variety of copulas capable of characterizing a broad range of dependence, the selection …

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Granular Activated Carbon Sorption As A Load Equalization Mechanism In Operation Of Air Pollution Control Devices, Marilou Montevirgen Nabatilan Jan 2009

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 …

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An Uncertainty-Based Approach To The Total Maximum Daily Load Development, Abhijit Patil Jan 2009

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 …

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Slab-On-Girder Prestressed Concrete Bridges: Linear And Nonlinear Finite Element Analysis And Experimental Load Tests, Marcio Costa Araujo Jan 2009

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 …

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The Study Of Sediment Dynamics In A Shallow Estuary Using Integrated Numerical Modeling And Satellite Remote Sensing, Haihong Zhao Jan 2009

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 …

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Redutive Dehalogenation Of Chlorinated Alkanes By Novel Bacteria At The Petroprocessor Of Louisiana Inc. Superfund Site, Jun Yan Jan 2008

Redutive Dehalogenation Of Chlorinated Alkanes By Novel Bacteria At The Petroprocessor Of Louisiana Inc. Superfund Site, Jun Yan

LSU Doctoral Dissertations

A reductively dehalogenating enrichment culture was established using chloroalkane-contaminated groundwater from the PetroProcessors of Louisiana, Inc. (PPI) Superfund site. Two novel, strictly anaerobic bacterial strains, designated as BL-DC-8 and BL-DC-9, were isolated from the enrichment culture. These strains represent the first bacteria known to anaerobically dehalogenate 1,2,3-trichloropropane, the degradation pathway of which was determined. Both strains could be cultured in completely defined basal medium and were also able to dehalogenate a variety of other vicinally chlorinated alkanes including 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, 1,2-dichloroethane, and 1,2-dichloropropane via dichloroelimination reactions. Chlorinated alkanes containing only a single chlorine substituent (1-chloropropane, 2-chloropropane), chlorinated alkenes (tetrachloroethene, trichloroethene, …

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Bayesian Model Averaging On Hydraulic Conductivity Estimation And Groundwater Head Prediction, Xiaobao Li Jan 2008

Bayesian Model Averaging On Hydraulic Conductivity Estimation And Groundwater Head Prediction, Xiaobao Li

LSU Doctoral Dissertations

Characterization of aquifer heterogeneity is inherently difficult because of the insufficiency of data, the inflexibility of parameterization methods, and non-uniqueness of parameterization methods. Groundwater predictions are greatly affected by multiple interpretations of aquifer properties and the uncertainties of model parameters. This study introduces a Bayesian model averaging (BMA) method along with multiple generalized parameterization (GP) methods to identify hydraulic conductivity and along with multiple simulation models to predict groundwater head and quantify the prediction uncertainty. Two major issues about BMA are discussed. The first problem is with using Occam’s window in usual BMA applications. Occam’s window only accepts models in …

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Lattice Boltzmann Modeling For Mass Transport Equations In Porous Media, Borja Servan Camas Jan 2008

Lattice Boltzmann Modeling For Mass Transport Equations In Porous Media, Borja Servan Camas

LSU Doctoral Dissertations

The aim of this dissertation is to extend the lattice Boltzmann method (LBM) to cope with parameter heterogeneity and anisotropy in mass transport equations in porous media, as well as investigating the stability and accuracy. Although the LBM is a well known and effective numerical method to solve fluid flows, LBM has not been extensively applied to mass transport equations in porous medium flow yet, and only a few works can be found on improving LBM to cope with mass transport equations other than the diffusion and advection-diffusion equations. One of the reasons why LBM has not been extensively used …

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Optimization Of Treatment Of Chlorinated Volatile Organic Compound Mixtures In Constructed Wetlands: Vegetation And Substrate Effects, Stephen Emmanuel Mbuligwe Jan 2008

Optimization Of Treatment Of Chlorinated Volatile Organic Compound Mixtures In Constructed Wetlands: Vegetation And Substrate Effects, Stephen Emmanuel Mbuligwe

LSU Doctoral Dissertations

Microcosm and mesocosm scale experiments were carried out to investigate the effects of vegetation and substrates on the performance of engineered wetland systems (EWSs) meant to treat mixtures of volatile organic compounds (cVOCs). The experiments were conducted with a view to optimizing contributions of these wetland components. Phragmites communis and Typha latifolia, the commonest wetland plant species, were compared in mesocosm scale EWSs. Eight common wetland plant species were compared using microcosm experiments based on the potential of their rootmatter to enhance treatment of cVOC mixtures. Twelve common wetland plants were similarly compared but on the basis of their aboveground …

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Development Of An Ultrasonic Nde&T Tool For Yield Detection In Steel Structures, Yilmaz Bingol Jan 2008

Development Of An Ultrasonic Nde&T Tool For Yield Detection In Steel Structures, Yilmaz Bingol

LSU Doctoral Dissertations

Nondestructive Evaluation and Testing (NDE&T) is a commonly used and rapidly growing field that offers successful solutions for health assessment of structures. NDE&T methods have gained increasing attention in the last few decades especially with the contribution of the advancements in computer and instrumentation technologies. The applications of numerous NDE&T methods in civil engineering mostly focus on material characterization and defect detection. Techniques for nondestructively identifying the stress state in materials, on the other hand, mostly rely on the Theory of Acoustoelasticity. However, the sensitivity and the accuracy of acoustoelasticity are affected by several factors such as the microstructure of …

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Factors Affecting Young Driver Safety In The State Of Louisiana, Cherian Cherian-Korah Jan 2008

Factors Affecting Young Driver Safety In The State Of Louisiana, Cherian Cherian-Korah

LSU Master's Theses

Though teenage drivers constitute only 6.4 percent of the total drivers in United States, they are responsible for 14 percent of the fatal crashes and are involved in 18 percent of all police-reported crashes in the country. One of the main causes of teenage crashes was found to be the presence of passengers in the vehicle. This study is focused on the effect of passengers on young drivers in the state of Louisiana. There have been efforts from traffic safety departments to contain crashes involving this age group of drivers and, particularly the Graduated Driver's License Law, which imposes restrictions …

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