Engineering Commons^™

Development And Application Of Dynamic Models For Predicting Transit Arrival Times, Yuqing Ding

Dissertations

Stochastic variations in traffic conditions and ridership often have a negative impact in transit operations resulting in the deterioration of schedule/headway adherence and lengthening of passenger wait times. Providing accurate information on transit vehicle arrival times is critical to reduce the negative impacts on transit users. In this study, models for dynamically predicting transit arrival times in urban settings are developed, including a basic model, a Kalman filtering model, link-based and stop-based artificial neural networks (ANNs) and Neural/Dynamic (ND) models. The reliability of these models is assessed by enhancing the microscopic simulation program CORSIM which can calculate bus dwell and …

The Influence Of High Performance Matrices On Fracture Behavior Of Concrete, Pusit Lertwattanaruk

Dissertations

Modification of cement matrices by the addition of micro particle pozzolanic materials such as silica fume and fly ash is known to improve the strength of concrete, but its contributions to fracture behavior remains unclear. In this study, the influence of replacing cement by silica fume and fly ash on the cement matrix-coarse aggregate interfacial bond, compressive stress-strain behavior and fracture behavior of concrete is investigated.

While the linear elastic fracture mechanics (LEFM) concept is not appropriate for concrete, a nonlinear fracture model based on the load vs. load-line deflection and the load vs. crack-mouthopening displacement (CMOD) responses of the …

Utilization Of Municipal Solid Waste Incinerator Fly Ash In Cement Mortars, Manaskorn Rachakornkij

Dissertations

Disposal of municipal solid waste has become a major problem in many countries around the world. With the benefits of substantial weight and volume reduction and potential energy recovery, incineration has become a promising municipal solid waste (MSW) management option. Despite the fact that incineration reduces volume and mass of the wastes by as much as 80%, there are still residues to be properly managed. This research is aimed at evaluating the potential of different types of MSWI fly ash from an incineration facility to be used in cement mortars by using existing standard test methods for cement and coal …

Finite Fraction Method For Tracking Desinfection By-Product Precursors In Water Treatment, Doanh Van

Dissertations

Dissolved Organic Matter (DOM) has been the subject of recent regulatory activities and agenda. Among them are the Infonnation Collection Rule (ICR), the Disinfectants/Disinfection By-Product Rule (D/DBPR) and the Interim Enhanced Surface Water Treatment Rule (ESWTR). Both the latter two have provisions to limit the formation of disinfection by-products (DBP) by controlling reactivity and removal of DOM or both. Brief regulatory review of these rules was given.

Although the topic of DBP formation potential and DBP precursor removal have been studied by many researchers since Rooks (1974), the efficacy of methods that have been developed to date has been handicapped …

Intelligent Process For Uasb Reactors, Sita Mohan

Theses

The Upflow Anaerobic Sludge Blanket (UASB) reactor is widely used for the anaerobic treatment of concentrated municipal / industrial wastewaters and sludges. Ability to handle high organic loading rates and cost effectiveness are often the most cited merits of the UASB process. Numerous mathematical models have been developed to describe the process and mechanistic phenomena in these systems. However, evidence in the literature of these models having been applied, either as control or diagnostic tools is limited. The use of intelligent process control mechanisms can greatly ease problems associated with operating these reactor systems.

The objective of this study is …

Post-Cracking Tensile Properties Of Advanced Cementitious Materials And Ductility Of High Performance Concrete Beams, Wonsiri Punurai

Theses

In present direct tension tests, the complete stress-deformation curves, the resulting energy dissipated by damage, and the fracture energy of different types of cementitious composites, namely plain concrete, high strength concrete, normal fibrous concrete, high strength fibrous concrete, are studied and a ductility factor is calculated. It has been found that with the increasing strength of concrete due to the addition of the pozzoians such as silica fume and fly ash and when changing from normal strength to high strength, concrete ductility decreases. However, when fibers are combined with these matrices, concrete ductility increases. It is because of ductile steel …

Measurement Of Microcarrier Weighted Floc Using The Environmental Electron Microscope, Viriya Vithayaveroj

Theses

Utilizing the concept of coagulation in conjunction with the sediment enhancement by microcarrier, the microcarrier process has been demonstrated in a laboratory investigation as an effective and economic operation in removing colloidal particles in an aquatic system. The microcarrier, an inert aluminum silicate particulate (Ottawa Sand) of 53 to 75 micrometers in diameter was used in this study. The interaction between the flocs and the microcarriers plays an important role in the mixing process. The principal objective of this study is to examine the structural interaction between the flocs and the microcarrier.

The study was designed into two stages, the …

Applicability Of The River Conservative Model For Heavy Metals Calculations In Egypt, Amr Mohammad Osama Abdel Aziz

Archived Theses and Dissertations

No abstract provided.

Constitutive Modeling Of Cohesionless Granular Materials Using Disturbed State Concept., Prasad Madhava Samarajiva

LSU Historical Dissertations and Theses

No abstract provided.

Field Evaluation Of Ultrasound Enhancement Of Permeable Treatment Walls, Aamod Sudhakar Sonawane

Retrospective Theses and Dissertations

The objective of this research was to demonstrate the application of ultrasound to field sites having problems with precipitation build up and corrosion. PTW s are passive reactive walls containing zero-valent iron metal for in-situ remediation of contaminated groundwater. However, loss of reactivity over time due to build up of corrosion and other precipitates on the iron surface is a major concern. Ultrasound energy has been established as an effective tool for revitalizing iron surface. This research applied ultrasound energy to a zero-valent iron wall constructed below the ground surface to remove precipitates and iron corrosion, increasing iron reactivity. Two …

Developing An Effective Mechanism Of Oil Pollution Management In The Niger Delta, Ja'afaru Labaran Daura

World Maritime University Dissertations

No abstract provided.

Improved Regression-Based Streamflow Forecasting Considering Large-Scale Climate Variability, Austin R. Fisher

Dissertations and Theses

The Natural Resources Conservation Service (NRCS) produces water supply forecasts for most of the streams in the western United States. The NRCS produces forecasts starting in January, when snow course measurements of snow water equivalent were available. Although the seasonal streamflow volume forecasts made by the NRCS are useful, many water supply managers need information at the beginning of the water year in October and would like to see forecasts in the form of a monthly hydrograph.

An investigation into the effect of decadal scale variability, as reflected by the Pacific Decadal Oscillation (PDO), show important relationships that may be …