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2004

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Articles 691 - 711 of 711

Full-Text Articles in Civil and Environmental Engineering

Modeling Event-Based Coupled Hydrologic And Mass Transport In Small Urban Watersheds, Yuhong Sheng Jan 2004

Modeling Event-Based Coupled Hydrologic And Mass Transport In Small Urban Watersheds, Yuhong Sheng

LSU Doctoral Dissertations

To investigate the event-based coupled hydrologic and mass transport processes of particulate matter and their eventual fate in unit operations/processes, several methodologies were developed. Discrete rainfall-runoff events data were collected at two similar urban watersheds for model calibration and verification. A mathematically and physically-based criterion was proposed to differentiate rainfall-runoff events between either mass-limited or flow-limited. Statistical techniques of Logistic Regression and Discriminant Analysis were utilized to derive classification rules for event categories based on hydrologic data only. With watersheds assumed as either lumped systems or distributed systems, physically-based semi-empirical models were developed to simulate particulate mass delivery process during …

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Development Of Dynamic Travel Demand Models For Hurricane Evacuation, Haoqiang Fu Jan 2004

Development Of Dynamic Travel Demand Models For Hurricane Evacuation, Haoqiang Fu

LSU Doctoral Dissertations

Little attention has been given to estimating dynamic travel demand in transportation planning in the past. However, when factors influencing travel are changing significantly over time – such as with an approaching hurricane - dynamic demand and the resulting variation in traffic flow on the network become important. In this study, dynamic travel demand models for hurricane evacuation were developed with two methodologies: survival analysis and sequential choice model. Using survival analysis, the time before evacuation from a pending hurricane is modeled with those that do not evacuate considered as censored observations. A Cox proportional hazards regression model with time-dependent …

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Software For Optimizing International Water Resources Management, Richard C. Peralta, S. Wu Jan 2004

Software For Optimizing International Water Resources Management, Richard C. Peralta, S. Wu

Civil and Environmental Engineering Faculty Publications

The Simulation/Optimization MOdeling System (SOMOS) has modules adapted for a range of international water resource management needs. The SOMOA module is best for field groundwater and conjunctive water management situations. It employs several analytical simulation models and several optimization methods to give appropriate optimal guidance for situations having sparse data. SOMOA requires understanding of the limitations of common analytical equations. It does not require experience in finite difference or element numerical modeling. SOMOS also has modules ideal for situations in which there is sufficient data for numerical modeling or aquifer and stream-aquifer systems. Emphasized here are SOMOA and its applications …

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Multi-Objective Conjunctive Use Optimization, H. C. Fayad, Richard C. Peralta Jan 2004

Multi-Objective Conjunctive Use Optimization, H. C. Fayad, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

This paper presents a simulation/optimization model based on artificial neural networks and genetic algorithms for solving multi-objective conjunctive water use problems. The model simulates and optimizes water flows in a hydraulically connected reservoir-stream-aquifer system. It is a powerful tool to help water managers and authorities in developing conjunctive water management strategies and evaluating tradeoffs between conflicting goals.

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Optimization Modeling For Groundwater And Conjunctive Use Water Policy Development, Richard C. Peralta, R. Shulstad Jan 2004

Optimization Modeling For Groundwater And Conjunctive Use Water Policy Development, Richard C. Peralta, R. Shulstad

Civil and Environmental Engineering Faculty Publications

Planners must sometimes decide how to restrict or reduce groundwater use to prevent unacceptable future problems. Often there are several alternatives (policies). Comparing policies can involve formulating a sustained groundwater yield optimization problem and computing an optimal groundwater pumping strategy for each. This is easy via the SOMOS simulation/optimization (S/O) model. Subsequent analysis can include: flow simulation to predict transient water level response to pumping; and economic evaluation to estimate costs and returns. Two examples predict the best consequences of potential physical and legal management policies for alluvial and valley basin fill aquifers hydraulically linked to surface waters. Results show …

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A Proposal For Re-Engineering The Procurement Of Building Materials By Effective Use Of Ict, Alan V. Hore, Roger West Jan 2004

A Proposal For Re-Engineering The Procurement Of Building Materials By Effective Use Of Ict, Alan V. Hore, Roger West

Conference papers

This paper seeks to establish the case for re-engineering the procurement of materials in the Irish construction industry. The authors make their observations from witnessing, first-hand, the operation of a purchasing function in a large contracting organisation in the Republic of Ireland. The authors identify the core problems that exist in the current mainly paper-based process and present a strong case for the re-engineering of the process by the adoption of a fully integrated Information Communications Technology (ICT) solution

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An Evaluation Of Methods Used To Obtain The Railroad Preemption Queue Clearance Time, Deeangela Renee Kenon Jan 2004

An Evaluation Of Methods Used To Obtain The Railroad Preemption Queue Clearance Time, Deeangela Renee Kenon

LSU Master's Theses

Because of the potential for serious train-vehicle accidents at or near railroad-highway grade crossings, preemption of traffic signals is a very important supplement to an active warning system. Preemption is the transfer of normal signal phasing to a special control mode with the purpose of clearing any vehicles that are queued within the dynamic envelope as the train approaches, and prohibiting signal phases that would allow additional vehicles in the track area while the train is present. The focus of this research was the determination of the Clear Track Green Interval (or the Queue Clearance Time). The clear track green …

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Mems Accelerometer: Proof Of Concept For Geotechnical Engineering Testing, Keith Nicholas Hoffman Jan 2004

Mems Accelerometer: Proof Of Concept For Geotechnical Engineering Testing, Keith Nicholas Hoffman

LSU Master's Theses

Geotechnical engineering materials are inherently variable, which leads to many simplifications when trying to model their behavior. The materials must always be characterized prior to any design work so that the engineer knows which direction he must progress to have a reliable design. Although subsurface characterization techniques and geotechnical design steadily improve, they are by no means infallible. The combination of geotechnical subsurface characterization along with geophysical techniques for improved design and construction monitoring has begun to surface as a viable alternative to the standard techniques in geotechnical engineering. This is important because there is a lack of Quality Control/Quality …

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Travel Time Tomographic Imaging Of The Distribution Of The Effective Stress In Clean Sand Under A Model Footing, William M. Tanner Jan 2004

Travel Time Tomographic Imaging Of The Distribution Of The Effective Stress In Clean Sand Under A Model Footing, William M. Tanner

LSU Master's Theses

The use of high-speed data acquisition systems, inexpensive and reliable transducers, and better models of interpretation have combined to make elastic wave tomographic imaging of geotechnical engineering systems easier to accomplish both in the laboratory and in the field. An important application of these developments is that the evaluation of states of effective stress in soils using images of elastic wave velocity distribution. As a consequence, it is possible to experimentally estimate the state of induced and in-situ effective stresses and to compare these results with established models of stress distribution based on the theory of elasticity (e.g., Boussinesq’s solution). …

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Biological Treatment Of Industrial Wastewater Containing High Concentrations Of Linear Alkylbenzene Sulfonate (Las), Luis Alberto Espinoza Jan 2004

Biological Treatment Of Industrial Wastewater Containing High Concentrations Of Linear Alkylbenzene Sulfonate (Las), Luis Alberto Espinoza

LSU Master's Theses

Lauryl Alkylbenzene Sulfonate (LAS) is the major anionic surfactant used worldwide in detergent and household cleaning product formulations. Its biodegradation and removal has been extensively studied in wastewater treatment facilities and laboratory-scale tests at low concentrations (<10 mg/L) typical of those encountered in municipal wastewater treatment plants. Less effort, however, has been expended investigating degradation of higher concentrations of LAS representative of those expected in wastewater generated at LAS manufacturing operations. The research described in this thesis was conducted to study biological processes for treating wastewaters containing high concentrations (e.g., 400 mg/L) of LAS. Initial experiments were carried out using a respirometry technique, and subsequently, three different laboratory-scale bioreactor systems. The three systems studied were a Sequencing Batch Reactor (SBR), a Sequencing Batch Biofilm Reactor (SBBR), and an Intermittent Cycle Extension Aeration System (ICEAS). The SBR and ICEAS were operated on a five-day cycle basis with a hydraulic retention time of four days. The SBBR was operated mainly in a two-day cycle having a hydraulic retention time of ten days as well, and polyurethane foam cubes were used as a support medium for attached biomass growth. The three systems were compared on their ability to remove LAS measured in terms of total organic carbon (TOC) and methylene blue active substances (MBAS). The reactors were also compared on the basis of foam production. The ICEAS showed the best performance in terms of controllable foam production while exhibiting a capacity for effectively dealing with transient periods of elevated loading. When a short Fill period was used, the SBR and SBBR had the disadvantage of producing excessive foaming, and an intermittent aeration strategy was required avoid overflow.

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Numerical Modeling Of Strain Localization In Granular Materials Using Cosserat Theory Enhanced With Microfabric Properties, Mustafa Alsaleh Jan 2004

Numerical Modeling Of Strain Localization In Granular Materials Using Cosserat Theory Enhanced With Microfabric Properties, Mustafa Alsaleh

LSU Doctoral Dissertations

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 …

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Small And Large Strain Monitoring Of Unsaturated Soil Behavior By Means Of Multiaxial Testing And Shear Wave Propagation, Oscar F. Porras Ortiz Jan 2004

Small And Large Strain Monitoring Of Unsaturated Soil Behavior By Means Of Multiaxial Testing And Shear Wave Propagation, Oscar F. Porras Ortiz

LSU Doctoral Dissertations

The deformation and strength behavior of dry and saturated soils is controlled by the effective stresses as defined by Terzaghi. However, Terzaghi’s 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 …

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Modeling Of River Hydrodynamics And Active Cap Effectiveness In The Anacostia River, Keegan L. Roberts Jan 2004

Modeling Of River Hydrodynamics And Active Cap Effectiveness In The Anacostia River, Keegan L. Roberts

LSU Master's Theses

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) …

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Experimental And Computational Modeling Of Granular Materials, Orlando Boscan Jan 2004

Experimental And Computational Modeling Of Granular Materials, Orlando Boscan

LSU Master's Theses

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 …

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Development Of Indiana's Sps9-A Site, Ayesha Shah, J. Olek Jan 2004

Development Of Indiana's Sps9-A Site, Ayesha Shah, J. Olek

JTRP Technical Reports

The Superpave system for hot mix asphalt (HMA) design was introduced in 1995 and adopted throughout most of the USA by 2000. This system uses performance-oriented approach to materials selection and mix design, and takes into account the local environmental and traffic conditions. It recognizes that the behavior of HMA depends on the temperature, loading and aging conditions and provides tools (in the form of materials selection and performance-related tests) that should help to protect pavements against low-temperature cracking, rutting and fatigue cracking. This report summarizes the field and laboratory studies conducted to investigate the influence of asphalt binder grade …

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Evaluation Of Indot Hyperfix Project, Kumares C. Sinha, Bob G. Mccullouch, Darcy M. Bullock, Sravanthi Konduri, Jon D. Fricker, Samuel Labi Jan 2004

Evaluation Of Indot Hyperfix Project, Kumares C. Sinha, Bob G. Mccullouch, Darcy M. Bullock, Sravanthi Konduri, Jon D. Fricker, Samuel Labi

JTRP Technical Reports

In 2003 the Indiana Department of Transportation executed an ambitious interstate reconstruction project in Indianapolis, named Hyperfix. This project completely closed the I-65/70 section during reconstruction, on which approximately 250,000 vehicles travel daily. Due to the scope and risk involved, an extensive amount of planning, coordination, and cooperation occurred. The main section was rebuilt during the total closure phase, which lasted 55 days. The total closure approach had never been performed before by INDOT on such a high volume artery in a downtown metropolitan area. This present study analyzed the project and its impact on the Indianapolis area. The report …

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New Combination Treatments For Control Of Johnsongrass Along Roadsides, D. James Morré Jan 2004

New Combination Treatments For Control Of Johnsongrass Along Roadsides, D. James Morré

JTRP Technical Reports

This project was to develop a cost-effective method for chemical eradication of Johnsongrass along Indiana roadsides. Johnsongrass, together with Canada thistle, represents Indiana’s most serious noxious weed invader where the need for control is mandated by law. Combined target-directed laboratory and greenhouse studies identified a new candidate herbicide, Outrider, which when combined with a new additive designated TR-IV gives eradication of Johnsongrass when applied to plants after less than 20 inches (70 cm) of growth or regrowth following mowing. The combination does not harm oversprayed established fescue or bluegrass. Based on limited implementation activities (two years experience), the recommendation is …

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Modeling The Hydrologic And Particulate Loadings From Paved Urban Surfaces, Chad Michael Cristina Jan 2004

Modeling The Hydrologic And Particulate Loadings From Paved Urban Surfaces, Chad Michael Cristina

LSU Doctoral Dissertations

This dissertation details the results of recent investigations concerning non-colloidal particulate matter found in urban rainfall-runoff and urban snowmelt. Three forms of the power law model (PLM) were used to model particle number density. It was found that significant model error could be introduced into PLMs when the median diameter particle was used to estimate the number of particles per interval, but the SSE of continuous PLMs could be significantly reduced through the use of correction factors when the sieve interval was large (P<0.05). Additionally, a multiple PLM analysis may be more appropriate than a single PLM analysis when changes in particle population occur within a single gradation. PLMs were also used to model the relationship between cumulative granulometric mass and cumulative particulate-bound metal mass. The use of such calibrated PLMs provided considerable cost reduction when compared to conventional direct measurements of particulate-bound metal mass. A first flush analysis indicated that only events with average volumetric flow rates approaching 1 L/min/m of drainage width exhibit a rapid depletion of particulate matter consistent with the concentration-based definition of the first flush. An analysis of particle separation mechanisms indicated that 90% of these particles, by mass, could be removed from the discharge with detention times of 30 min and 120 min for snowmelt and rainfall-runoff, respectively, in a typical roadside drainage system. It was also found that the kinematic wave model could accurately model significant aspects of rainfall-runoff events in traffic-impacted watersheds provided that abstractions were incorporated into the modeling process. For this watershed the source of abstraction was attributable to vehicular traffic. For high-intensity events with more than 10 vehicles per runoff volume (VPV) the runoff coefficient varied between 0.6 and 0.9 while for low-intensity events with fewer than 10 VPV the coefficient ranged between 0.2 and 0.4.

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Material Length Scales In Gradient-Dependent Plasticity/Damage And Size Effects: Theory And Computation, Rashid Kamel Abu Al-Rub Jan 2004

Material Length Scales In Gradient-Dependent Plasticity/Damage And Size Effects: Theory And Computation, Rashid Kamel Abu Al-Rub

LSU Doctoral Dissertations

Structural materials display a strong size-dependence when deformed non-uniformly into the inelastic range: smaller is stronger. This effect has important implications for an increasing number of applications in structural failure, electronics, functional coatings, composites, micro-electro-mechanical systems (MEMS), nanostructured materials, micro/nanometer fabrication technologies, etc. The mechanical behavior of these applications cannot be characterized by classical (local) continuum theories because they incorporate no ‘material length scales’ and consequently predict no size effects. On the other hand, it is still not possible to perform quantum and atomistic simulations on realistic time and structures. It is therefore necessary to develop a scale-dependent continuum theory …

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Design And Operating Strategies For Bioreactors Treating Dynamically Varying Concentrations Of Gas-Phase Volatile Organic Compounds (Vocs), Congna Li Jan 2004

Design And Operating Strategies For Bioreactors Treating Dynamically Varying Concentrations Of Gas-Phase Volatile Organic Compounds (Vocs), Congna Li

LSU Doctoral Dissertations

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 …

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Dynamic Performance Of Bridges And Vehicles Under Strong Wind, Suren Chen Jan 2004

Dynamic Performance Of Bridges And Vehicles Under Strong Wind, Suren Chen

LSU Doctoral Dissertations

The record of span length for flexible bridges has been broken with the development of modern materials and construction techniques. With the increase of bridge span, the dynamic response of the bridge becomes more significant under external wind action and traffic loads. The present research targets specifically on dynamic performance of bridges as well as the transportation under strong wind. The dissertation studied the coupled vibration features of bridges under strong wind. The current research proposed the modal coupling assessment technique for bridges. A closed-form spectral solution and a practical methodology are provided to predict coupled multimode vibration without actually …

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