Engineering Commons^™

Feasibility Study To Extract Iron And Chromium From Chromium Contaminated Soils, Wiwat Kamolpornwijit

Dissertations

Chromium contaminated soils, besides being recognized for toxic and hazardous hexavalent chromium, contain high iron concentrations. At some sites, concentrations of iron oxide are higher than 30%. Both iron and chromium in soils have recyclable value provided they can be either concentrated in the oxide form or separated as metal. The concentrated oxide can be used as a substitute for the iron ore. The extracted metal can also be recycled in the steel industry. The objective of this study is to study the feasibility of extracting iron and chromium from soils.

Chromium contaminated soils, can be classified into two groups, …

Intermodal Transit System Coordination With Dynamic Vehicle Dispatching, Md. Shoaib Chowdhury

Dissertations

In most urban areas where transit demand is spread widely, passengers may be served by an intermodal transit system, consisting of a rail transit line (or a bus rapid transit route) and a numbers of feeder routes connecting at different transfer stations. In such a system, passengers may need one or more transfers to complete their journey. Therefore, scheduling vehicles operating in the system with special attention to reduce transfer time can contribute significantly service quality improvements. In this study two models, one for coordination of a general intermodal. transit system and another for dynamic dispatching of vehicles on coordinated …

Multimedia Modeling Of Organic Contaminants In The Passaic River Watershed, Lansana Coulibaly

Dissertations

A dynamic fate and transport multimedia environmental model was developed and applied to assess the release of five priority contaminants in the Passaic River Watershed, including: napthalene, toluene, trichloroethylene, 1-1-1 trichloroethane and xylene. The model uses the current releases of contaminants as well as cross-boundary advection to determine the fate and environmental distribution of these chemicals in the watershed. The model was developed using a dynamic fugacity approach in order to allow for scenario analysis such as source reductions and no-action alternatives. This modeling effort is expected to achieve a comprehensive assessment of contaminants not only in the proximity of …

Performance-Based Seismic Engineering Of Low And Medium-Rise Steel Frames, Saeid Rashidi

Dissertations

The performance level of low and medium-rise steel frames designed according to the common force/strength approach of the UBC or NEHRP is determined. Several combinations of soil profile type, lateral-force-resisting system, and frame-member proportioning are included in the designs.

To evaluate the expected damage, nonlinear models of the designed frames are subjected to a number of actual and simulated ground motion accelerograms and appropriate structural response parameters such as, interstory drift, ductility demand, and dissipated hysteretic energy are obtained. In addition, a modified form of Park-Ang damage index is calculated for moment-resisting frames. The seismic performance of the steel frames …

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 …

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 …

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 …

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 …