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2005

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Articles 421 - 436 of 436

Full-Text Articles in Civil and Environmental Engineering

The Benefits Of Deploying It In The Material Procurement In Ready Mix Concrete In The Irish Construction Industry, Alan V. Hore, Roger West Jan 2005

The Benefits Of Deploying It In The Material Procurement In Ready Mix Concrete In The Irish Construction Industry, Alan V. Hore, Roger West

Conference papers

The current methods of processing orders, deliveries and invoices of concrete products in the construction industry is enormously inefficient, with vast quantities of paperwork, duplication of effort, scanning, re-keying and resolving mismatches between purchase orders, delivery dockets and invoices. This paper sets out results of a survey which reveals attitudes to Information Communication Technologies (ICT) in supporting the purchasing process in construction. The drivers and barriers to ICT use in construction purchasing is discussed from both the contractor‟s and supplier‟s perspective. The paper goes on to describe the outcome of a pilot study in which the efficiencies are investigated arising …

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Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel Jan 2005

Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel

LSU Master's Theses

The mechanical behavior of granular materials is highly dependent on the arrangement of particles, particle groups, and associated pore spaces. Changes in the internal structure due to large deformation may cause changes in the mechanical behavior. The changes include: particle sliding, rolling, and interaction; shear band formation; and fabric anisotropy. During those changes, stick-slip behavior may take place between the granular particles. The objective of the thesis is to study the factors that influence the stick-slip behavior of granular materials. The influence of particle size, uniformity, confining pressure, density, and strain rate are investigated in this thesis. A series of …

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Experimental Quantification And Dem Simulation Of Micro-Macro Behaviors Of Granular Materials Using X-Ray Tomography Imaging, Yanrong Fu Jan 2005

Experimental Quantification And Dem Simulation Of Micro-Macro Behaviors Of Granular Materials Using X-Ray Tomography Imaging, Yanrong Fu

LSU Doctoral Dissertations

A non-invasive experimental method and a clustering DEM model were developed in this study to investigate micro-macro behaviors of real granular materials with irregular particle shape configurations. The investigated behaviors include global deformations, failure strengths and residual strengths, stress and strain distributions, local coordination number, local void ratio, particle kinematics, and fabric orientation distributions. The experimental method includes an approach to automatically identify and recognize multiple particles using x-ray computed tomography imaging (XCT) and an enhanced approach to digitally represent microstructures of granular materials. The digitally represented microstructure can be directly employed for numerical simulation setup. A compression test and …

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Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano Jan 2005

Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano

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. Over the past twelve years, MUSs have been installed in Port Fourchon, Louisiana, Moss Point, Mississippi, and Bayou Segnette, Louisiana. The purpose of this study was to investigate the nitrogen reduction capabilities of the Bayou Segnette system. The objectives of this research were to: 1) determine the first-order removal constants necessary for the development of nitrogen transport equations, 2) explore the spatial dependencies of nitrogen concentrations within the Bayou Segnette system, and 3) determine the …

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Finite Element Modeling Approach And Performance Evaluation Of Fiber Reinforced Polymer Sandwich Bridge Panels, Stanley Onyema Oghumu Jan 2005

Finite Element Modeling Approach And Performance Evaluation Of Fiber Reinforced Polymer Sandwich Bridge Panels, Stanley Onyema Oghumu

LSU Master's Theses

In the USA alone, about 27% of the bridges are classified as structurally deficient or functionally obsolete. Bridge owners are continually investigating methods to effectively retrofit existing bridges, or to economically replace them with new ones. Modern composite materials for structural applications, at one time only in the domain of aerospace engineering, are increasingly making their way into civil engineering applications. In addition to retrofitting current concrete and steel structures using FRP sheets or plates, a great deal of work is being conducted to develop versatile, fully-composite structural bridge systems. To reduce the self-weight and also achieve the necessary stiffness, …

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Assessing The Needs For Intermediate Diaphragms In Prestressed Concrete Girder Bridges, Anand Kumar Chandolu Jan 2005

Assessing The Needs For Intermediate Diaphragms In Prestressed Concrete Girder Bridges, Anand Kumar Chandolu

LSU Master's Theses

Reinforced concrete Intermediate Diaphragms (IDs) are still being used in prestressed concrete (PC) girder bridges in Louisiana. Some of the advantages of providing IDs are disputed and also use of IDs increases the cost and time of construction. There is no consistency in the practice of providing IDs among various states and codes of practice and overall there is a lack of clarity on the effectiveness of IDs and their needs in prestressed concrete bridges. The objectives of this research are to assess the need of reinforced concrete (RC) IDs in PC girder bridges and to determine their effectiveness and …

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Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin Jan 2005

Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin

LSU Master's Theses

The major objective of this work is to relate continuum damage mechanics introduced through the concept of fabric tensors to composite materials within the framework of classical elasticity theory. A model of directional data-damage mechanics for composite materials is formulated using fabric tensors. In addition, a general hypothesis for damage mechanics is postulated. It is seen that the two available hypotheses of elastic strain equivalence and elastic energy equivalence may be obtained as special cases of the postulated general hypothesis. This general hypothesis is then used to derive the sought relationship between the damage tensor for composite materials and the …

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Comparison Of Various Indot Testing Methods And Procedures To Quantify Variability In Measured Bituminous And Concrete Properties, Terhi K. Pellinen, W. Jason Weiss, Thomas Kuczek, Geoffrey Dauksas Jan 2005

Comparison Of Various Indot Testing Methods And Procedures To Quantify Variability In Measured Bituminous And Concrete Properties, Terhi K. Pellinen, W. Jason Weiss, Thomas Kuczek, Geoffrey Dauksas

JTRP Technical Reports

This study was designed to analyze the variability associated with several test procedures used by the Indiana Department of Transportation (INDOT) in their Hot Mix Asphalt (HMA), portland cement concrete pavement (PCCP), and superstructure concrete protocols. The aim of this work was to document the variability associated with each of these test procedures toward application of this information of the development of acceptance criteria, pay factors, and pay incentives and disincentives. The studied parameters for HMA production included the air void content and VMA of the gyratory compacted mixture, in-place density, binder (asphalt) content, aggregate bulk specific gravity and water …

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Improvements In Groundwater Flow Modeling Through The Integration Of Resistivity Logs And Hydraulic Conductivity And The Use Of Variogram Uncertainty, Asheka Rahman Jan 2005

Improvements In Groundwater Flow Modeling Through The Integration Of Resistivity Logs And Hydraulic Conductivity And The Use Of Variogram Uncertainty, Asheka Rahman

LSU Doctoral Dissertations

This study developed a coregionalized model to estimate hydraulic conductivity using spatial cross correlation between hydraulic conductivity and borehole geophysical data (a transform of the formation factor). An experimental pseudocross variogram is used instead of a cross variogram because data are not collocated. Experimental variogram uncertainty is investigated using confidence intervals for the experimental variogram calculated assuming variogram sills are lognormally distributed. These intervals are used for sensitivity modeling using kriging, cokriging, simulation and cosimulation. The hydraulic conductivity fields generated by kriging, cokriging, simulation, and cosimulation are then used in a high-resolution groundwater model created using telescopic mesh refinement (TMR) …

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Physically Based Multiscale-Viscoplastic Model For Metals And Steel Alloys: Theory And Computation, Farid H. Abed Jan 2005

Physically Based Multiscale-Viscoplastic Model For Metals And Steel Alloys: Theory And Computation, Farid H. Abed

LSU Doctoral Dissertations

The main requirement of large deformation problems such as high-speed machining, impact, and various primarily metal forming, is to develop constitutive relations which are widely applicable and capable of accounting for complex paths of deformation. Achieving such desirable goals for material like metals and steel alloys involves a comprehensive study of their microstructures and experimental observations under different loading conditions. In general, metal structures display a strong rate- and temperature-dependence when deformed non-uniformly into the inelastic range. This effect has important implications for an increasing number of applications in structural and engineering mechanics. The mechanical behavior of these applications cannot …

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Speciation, Equilibria And Kinetics For Rainfall-Runoff Metals In Adsorptive-Filtration Unit Operations And Processes, Tianpeng Guo Jan 2005

Speciation, Equilibria And Kinetics For Rainfall-Runoff Metals In Adsorptive-Filtration Unit Operations And Processes, Tianpeng Guo

LSU Doctoral Dissertations

Populations transferred by rainfall runoff can have many adverse effects livings and people. Treatment of rainfall-runoff continues to pose unique challenges due to the unsteady nature of processes including mobilization, partitioning and transport of heavy metals as well as other constituent loads. BMPs that incorporate heavy metal removal are generating more attention as the nature of stormwater is better understood. This dissertation focused on metal partitioning and speciation in rainfall-runoff through the in-situ Partial Exfiltration Reactor (PER) and exposed to various redox circumstances, and metal removal by sorptive engineered manganese oxides coated media. Adsorption capacity of three manganese oxides coated …

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Speciation, Equilibrium Distribution And Kinetics Of Rainfall-Runoff Phosphorus In Adsorptive-Filtration Unit Operations And Processes, Jia Ma Jan 2005

Speciation, Equilibrium Distribution And Kinetics Of Rainfall-Runoff Phosphorus In Adsorptive-Filtration Unit Operations And Processes, Jia Ma

LSU Doctoral Dissertations

This study examined the influence of hydrology on rainfall runoff phosphorus partitioning between aqueous and particulate-bound phase, and dissolved phosphorus speciation at the upper end of a Cementitious Porous Pavement (CPP) small urban watershed. This study also investigated particulate bound phosphorus temporal distribution during storm event and phosphorus equilibrium distribution on a wide gradation of solids captured by hydrodynamic separator after the storm completed. Results indicate that EMC of urban rainfall runoff phosphorus exceeds EPA water quality criteria, with majority of particulate-bound phosphorus while rainfall by itself contains non-comparable low concentration of phosphorus. Dissolved phosphorus was mainly H2PO4- and HPO4-2 …

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Cementitious Permeable Pavement As A Passive Unit Operation And Process For Stormwater Quality And Quantity Control, Xuheng Kuang Jan 2005

Cementitious Permeable Pavement As A Passive Unit Operation And Process For Stormwater Quality And Quantity Control, Xuheng Kuang

LSU Doctoral Dissertations

With respect to the problems caused by impervious pavements, cementitous permeable pavement (CPP) functions as a passive unit operation and process for stormwater quality and quantity control through infiltration, evaporation, filtration, absorption and reaction mechanisms. CPP pore characteristics were examined through pore connectivity analysis using X-Ray Tomography (XRT). Image resolution influence on image analysis results was evaluated. Relationships between parameters of pore characteristics were evaluated. Factors that significantly influence fluid flow in CPP media include effective porosity, pore connectivity and pore size distribution. A modified Kozeny-Carman model in which effective porosity, specific surface area based on effective pores (SSA)pe, and …

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Halonitromethane Treatment Using Advanced Oxidation Process: Rates, Mechanisms And Kinetic Modeling, Stuart Kirkham Cole Jan 2005

Halonitromethane Treatment Using Advanced Oxidation Process: Rates, Mechanisms And Kinetic Modeling, Stuart Kirkham Cole

Civil & Environmental Engineering Theses & Dissertations

Halonitromethanes (HNMs) are low molecular weight halogenated disinfection-by-products (DBPs) found to be formed during ozonation, chlorination, or chloramination of waters containing natural bromide ion and nitrogenous organic matter. This work identifies the absolute rate constants for the oxidative hydroxyl radical (•OH) and reductive hydrated electron e- aq extinction of HNM compounds. Three forms of HNMs included in this study are the chlorinated, brominated, and mixed halogenated compounds. Electron pulse radiolysis and transient absorption spectroscopy were used to measure •OH and e- aq radical absolute reaction rate constants for a total of nine HNMs. To elucidate the decomposition reaction …

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Multivariate Hydrological Frequency Analysis And Risk Mapping, Lan Zhang Jan 2005

Multivariate Hydrological Frequency Analysis And Risk Mapping, Lan Zhang

LSU Doctoral Dissertations

In hydrological frequency analysis, it is difficult to apply standard statistical methods to derive multivariate probability distributions of the characteristics of hydrologic or hydraulic variables except under the following restrictive assumptions: (1) variables are assumed independent, (2) variables are assumed to have the same marginal distributions, and (3) variables are assumed to follow or are transformed to normal distribution. Relaxing these assumptions when deriving multivariate distributions of the characteristics of correlated hydrologic and hydraulic variables. The copula methodology is applied to perform multivariate frequency analysis of rainfall, flood, low-flow, water quality, and channel flow, using data from the Amite river …

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Biofiltration For Treatment Of Gas-Phase Voc Mixtures, Bing Qi Jan 2005

Biofiltration For Treatment Of Gas-Phase Voc Mixtures, Bing Qi

LSU Doctoral Dissertations

Biological processes are increasingly used for treatment of air streams contaminated by biodegradable volatile organic compounds (VOCs). The research described in this dissertation involves systematic investigation of various facets of applying biological processes dominated by fungi to remove mixtures of VOCs representative of emissions from paint application and manufacturing. Screening studies were first conducted to assess the ability of multiple fungal species to degrade various industrially important VOCs. In the following phases of the research, studies were conducted to evaluate performance of laboratory-scale bioreactors inoculated with fungi for treatment of mixtures of VOCs representative of emissions from paint spray booths …

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