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University of Central Florida

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Articles 511 - 540 of 627

Full-Text Articles in Civil and Environmental Engineering

Examining Route Diversion And Multiple Ramp Metering Strategies For Reducing Real-Time Crash Risk On Urban Freeways, Vikash Gayah Jan 2006

Examining Route Diversion And Multiple Ramp Metering Strategies For Reducing Real-Time Crash Risk On Urban Freeways, Vikash Gayah

Electronic Theses and Dissertations

Recent research at the University of Central Florida addressing crashes on Interstate-4 in Orlando, Florida has led to the creation of new statistical models capable of calculating the crash risk on the freeway (Abdel-Aty et al., 2004; 2005, Pande and Abdel-Aty, 2006). These models yield the rear-end and lane-change crash risk along the freeway in real-time by using static information at various locations along the freeway as well as real-time traffic data that is obtained from the roadway. Because these models use the real-time traffic data, they are capable of calculating the respective crash risk values as the traffic flow …

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Pervious Concrete: A Hydrologic Analysis For Stormwater Management Credit, Joshua Spence Jan 2006

Pervious Concrete: A Hydrologic Analysis For Stormwater Management Credit, Joshua Spence

Electronic Theses and Dissertations

Portland Cement pervious concrete's ability to permit water infiltration has encouraged its use as a stormwater management tool. However, the material has suffered historically poor support due to a number of factors, including failures due to poor mix design and improper construction techniques, concern about lesser structural strength, concern about poor long term performance due to clogging of surface pores and undefined credit for stormwater management. This study focuses on long term performances of pervious concrete parking lots and their stormwater management credit. Before stormwater management credit could be estimated, it was necessary to develop a testing device to gather …

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In-Situ Ammonia Removal Of Leachate From Bioreactor Landfills, Nicole Berge Jan 2006

In-Situ Ammonia Removal Of Leachate From Bioreactor Landfills, Nicole Berge

Electronic Theses and Dissertations

A new and promising trend in solid waste management is to operate the landfill as a bioreactor. Bioreactor landfills are controlled systems in which moisture addition and/or air injection are used as enhancements to create a solid waste environment capable of actively degrading the biodegradable organic fraction of the waste. Although there are many advantages associated with bioreactor landfills, some challenges remain. One such challenge is the ammonia-nitrogen concentration found in the leachate. The concentrations of ammonia-nitrogen tend to increase beyond concentrations found in leachate from conventional landfills because recirculating leachate increases the rate of ammonification and results in accumulation …

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Feasibility Study Of Evaluating Durability Of Cfrp-Strengthened Beams Using In-Situ Load Test, Carlos Turizo-Rico Jan 2006

Feasibility Study Of Evaluating Durability Of Cfrp-Strengthened Beams Using In-Situ Load Test, Carlos Turizo-Rico

Electronic Theses and Dissertations

In Florida a number of highway bridges were retrofitted on their reinforced concrete (RC) girders with carbon-fiber reinforced polymers (CFRP) during the 1990's. Their conditions, after being in service for approximately 10 years, are of significant interest to the State's highway authority, as well as researchers in the region. This paper will evaluate if a load test on one of such bridges, which was retrofitted with CFRP at the girders in the splash-zone and thus was subjected to severe environmental conditions, is a feasible technique to evaluate the actual condition of the CFRP. A 3-dimensional Finite Element Model (FEM) was …

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Removal Of Refractory Tkn From An Effluent Wastewater Using Sodium Ferrate, Lucia Lettie Jan 2006

Removal Of Refractory Tkn From An Effluent Wastewater Using Sodium Ferrate, Lucia Lettie

Electronic Theses and Dissertations

This research addresses refractory forms of nitrogen that, even with advanced biological nitrification-denitrification systems are not removed completely from domestic wastewater. TKN (Total Kjeldahl Nitrogen), ammonia plus organic nitrogen, is one of the forms to measure the levels of nitrogen present in effluent wastewaters. Ferrate, a strong oxidant, was used for the treatment of these nitrogen forms with the objective of producing nitrogen compounds that can be removed by subsequent biological processes. Bench-scale experiments were performed on effluent samples taken prior to chlorination from an Orlando, FL wastewater treatment facility, using a biological nutrient removal process. The samples were treated …

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Evaluation Of Prefermentation As A Unit Process Upon Biological Nutrient Removal Including Biokinetic And Wastewater Parameters, Terrence Mccue Jan 2006

Evaluation Of Prefermentation As A Unit Process Upon Biological Nutrient Removal Including Biokinetic And Wastewater Parameters, Terrence Mccue

Electronic Theses and Dissertations

The objective of this dissertation was to provide a controlled comparison of identical continuous flow BNR processes both with and without prefermentation in order to provide a stronger, more quantitative, technical basis for design engineers to evaluate the potential benefits of prefermentation to EBPR in treating domestic wastewater. In addition, the even less understood effect of prefermentation on denitrification kinetics and anoxic phosphorus (P) uptake was studied and quantified. Other aspects of BNR performance, which might change due to use of prefermentation, will also be addressed, including anaerobic stabilization. Potential benefits to BNR processes derived from prefermentation are compared and …

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Change Orders And Productivity Loss Quantification Using Verifiable Site Data, Engy Serag Jan 2006

Change Orders And Productivity Loss Quantification Using Verifiable Site Data, Engy Serag

Electronic Theses and Dissertations

Change orders occur frequently in most construction projects, where contract modifications that increase the contract value between 5 to 10% are expected. Changes occur not only because of errors and omissions, but also for other reasons such as scope of work changes, or changes because of unforeseen conditions encountered on the site; a problem which is very common in most heavy construction projects. Changes themselves might not cause productivity losses; in this case the damage calculation will be straightforward. However, changes may cause disruption in unchanged work where the working conditions are impacted, and as a result, lost productivity (inefficiency) …

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Sensitivity Analysis Of Aashto's 2002 Flexible And Rigid Pavement Design Methods, Sanjay Shahji Jan 2006

Sensitivity Analysis Of Aashto's 2002 Flexible And Rigid Pavement Design Methods, Sanjay Shahji

Electronic Theses and Dissertations

Over the years pavement design has been based on empirical equations developed from the American Association of State Highway Transportation Officials (AASHTO) road tests. The various editions of the AASHTO pavement design guide have served well for several decades; nevertheless many serious limitations existed for their continued use as the nation's primary pavement design procedure. For example, the traffic loads and truck sizes have increased over the years, the AASHTO design equations were derived based on the climatic conditions present at the Road Tests site, and the issue of aging materials was not addressed in the design. To overcome these …

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Modeling Of Atmospheric Refraction Effects On Traffic Noise Propagation, Ahmed El-Aassar Jan 2006

Modeling Of Atmospheric Refraction Effects On Traffic Noise Propagation, Ahmed El-Aassar

Electronic Theses and Dissertations

Traffic noise has been shown to have negative effects on exposed persons in the communities along highways. Noise from transportation systems is considered a nuisance in the U.S. and the government agencies require a determination of noise impacts for federally funded projects. There are several models available for assessing noise levels impacts. These models vary from simple charts to computer design models. Some computer models, i.e. Standard Method In Noise Analysis (STAMINA), the Traffic Noise Model (TNM) and the UCF Community Noise Model (CNM), have been used to predict geometric spreading, atmospheric absorption, diffraction, and ground impedance. However, they have …

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Variation Of Geotechnical Strength Properties With Age Of Landfills Accepting Biosolids, Kishore Pinapati Jan 2006

Variation Of Geotechnical Strength Properties With Age Of Landfills Accepting Biosolids, Kishore Pinapati

Electronic Theses and Dissertations

The solid portion of waste disposal, known as Municipal Solid Waste (MSW) can be landfilled. Landfilling has proved to be a safe, sanitary and economical method of disposal. A by-product from wastewater treatment plants called biosolids is sometimes co-disposed along with MSW in landfills. Recent work at the University of Central Florida has focused on the behavior of the mixture of MSW and biosolids. As an increased amount of waste accumulates in these landfills, it creates a new problem – the geotechnical stability of landfills. In current literature, classical geotechnical testing methods have been followed to find the strength properties …

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A Three-Dimensional Bay/Estuary Model To Simulate Water Quality Transport, Jing Yu Jan 2006

A Three-Dimensional Bay/Estuary Model To Simulate Water Quality Transport, Jing Yu

Electronic Theses and Dissertations

This thesis presents the development of a numerical water quality model using a general paradigm of reaction-based approaches. In a reaction-based approach, all conceptualized biogeochemical processes are transformed into a reaction network. Through the decomposition of species governing equations via Gauss-Jordan column reduction of the reaction network, (1) redundant fast reactions and irrelevant kinetic reactions are removed from the system, which alleviates the problem of unnecessary and erroneous formulation and parameterization of these reactions, and (2) fast reactions and slow reactions are decoupled, which enables robust numerical integrations. The system of species transport equations is transformed to reaction-extent transport equations, …

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Driving Simulator Validation And Rear-End Crash Risk Analysis At A Signalised Intersection, Praveen Chilakapati Jan 2006

Driving Simulator Validation And Rear-End Crash Risk Analysis At A Signalised Intersection, Praveen Chilakapati

Electronic Theses and Dissertations

In recent years the use of advanced driving simulators has increased in the transportation engineering field especially in evaluating safety countermeasures. The driving simulator at UCF is a high fidelity simulator with six degrees of freedom. This research aims at validating the simulator in terms of speed and safety with the intention of using it as a test bed for high risk locations and to use it in developing traffic safety countermeasures. The Simulator replicates a real world signalized intersection (Alafaya trail (SR-434) and Colonial Drive (SR-50)). A total of sixty one subjects of age ranging from sixteen to sixty …

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Effectiveness And Kinetics Of Ferrate As A Disinfectant For Ballast Water, Andrea L. Jessen Jan 2006

Effectiveness And Kinetics Of Ferrate As A Disinfectant For Ballast Water, Andrea L. Jessen

Electronic Theses and Dissertations

The introduction of aquatic nuisance species (ANS) and bacterial pathogens from discharge of ballast water by sea-faring vessels is an ongoing problem that threatens ecosystems and human health. This study investigates the disinfecting capability of ferrate in a marine environment on several organisms listed in international standards for ballast water management. Organisms were grown in a saline solution and were treated with dosages of ferrate ranging from 0.25-5.0 mg/l. A ferrate dose of 5 mg/l resulted in almost complete kill for all organisms tested. Smaller dosages have also been very effective, particularly if all organic material from the nutrient broth …

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Developing Emergency Preparedness Plans For Orlando International Airport (Mco) Using Microscopic Simulator Watsim, Daniel Dawson Jan 2006

Developing Emergency Preparedness Plans For Orlando International Airport (Mco) Using Microscopic Simulator Watsim, Daniel Dawson

Electronic Theses and Dissertations

Emergency preparedness typically involves the preparation of detailed plans that can be implemented in response to a variety of possible emergencies or disruptions to the transportation system. One shortcoming of past response plans was that they were based on only rudimentary traffic analysis or in many cases none at all. With the advances in traffic simulation during the last decade, it is now possible to model many traffic problems, such as emergency management, signal control and testing of Intelligent Transportation System technologies. These problems are difficult to solve using the traditional tools, which are based on analytical methods. Therefore, emergency …

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Analysis, Modeling, And Simulation Of The Tides In The Loxahatchee River Estuary (Southeastern Florida)., Peter Bacopoulos Jan 2006

Analysis, Modeling, And Simulation Of The Tides In The Loxahatchee River Estuary (Southeastern Florida)., Peter Bacopoulos

Electronic Theses and Dissertations

Recent cooperative efforts between the University of Central Florida, the Florida Department of Environmental Protection, and the South Florida Water Management District explore the development of a two-dimensional, depth-integrated tidal model for the Loxahatchee River estuary (Southeastern Florida). Employing a large-domain approach (i.e., the Western North Atlantic Tidal model domain), two-dimensional tidal flows within the Loxahatchee River estuary are reproduced to provide: 1) recommendations for the domain extent of an integrated, surface/groundwater, three-dimensional model; 2) nearshore, harmonically decomposed, tidal elevation boundary conditions. Tidal simulations are performed using a two-dimensional, depth-integrated, finite element-based code for coastal and ocean circulation, ADCIRC-2DDI. Multiple …

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Utilizing A Real Life Data Warehouse To Develop Freeway Travel Time Eliability Stochastic Models, Emam Emam Jan 2006

Utilizing A Real Life Data Warehouse To Develop Freeway Travel Time Eliability Stochastic Models, Emam Emam

Electronic Theses and Dissertations

During the 20th century, transportation programs were focused on the development of the basic infrastructure for the transportation networks. In the 21st century, the focus has shifted to management and operations of these networks. Transportation network reliability measure plays an important role in judging the performance of the transportation system and in evaluating the impact of new Intelligent Transportation Systems (ITS) deployment. The measurement of transportation network travel time reliability is imperative for providing travelers with accurate route guidance information. It can be applied to generate the shortest path (or alternative paths) connecting the origins and destinations especially under conditions …

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Coordination, Matchmaking, And Resource Allocation For Large-Scale Distributed Systems, Xin Bai Jan 2006

Coordination, Matchmaking, And Resource Allocation For Large-Scale Distributed Systems, Xin Bai

Electronic Theses and Dissertations

In this research, statistical models of airport delay and single flight arrival delay were developed. The models use the Airline On-Time Performance Data from the Federal Aviation Administration (FAA) and the Surface Airways Weather Data from the National Climatic Data Center (NCDC). Multivariate regression, ANOVA, neural networks and logistic regression were used to detect the pattern of airport delay, aircraft arrival delay and schedule performance. These models are then integrated in the form of a system for aircraft delay analysis and airport delay assessment. The assessment of an airport¡¯s schedule performance is discussed. The results of the research show that …

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Hydrologic Mass Balance Of Pervious Concrete Pavement With Sandy Soils, Thomas Kunzen Jan 2006

Hydrologic Mass Balance Of Pervious Concrete Pavement With Sandy Soils, Thomas Kunzen

Electronic Theses and Dissertations

Use of pervious concrete pavement as a method of stormwater management has shown great promise in previous studies. Reduction in runoff, water quality improvements, and long-term economic benefits are but a few of its many advantages. Regulatory agencies such as the St. Johns River Water Management District require further research into the performance of pervious concrete pavement before granting credits for its use as a best management practice in controlling stormwater. As a part of a larger series of studies by UCF's Stormwater Management Academy, this thesis studies the hydrologic mass balance of pervious concrete pavement in sandy soil common …

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The Effects Of Ph On Enhanced Biological Phosphorus Removal (Ebpr) With Propionic Acid As The Dominant Volatile Fatty Acid (Vfa), Seyed Malekjahani Jan 2006

The Effects Of Ph On Enhanced Biological Phosphorus Removal (Ebpr) With Propionic Acid As The Dominant Volatile Fatty Acid (Vfa), Seyed Malekjahani

Electronic Theses and Dissertations

pH control is a tool to improve some aspects of Enhanced Biological Phosphorus Removal (EBPR) process. Filipe et al (2001a, 2001b, and 2001c) found strong evidence that the stability of EBPR systems can be improved by increasing the pH of the anaerobic zone, thereby creating conditions where phosphorus-accumulating organisms (PAOs) are able to take up acetate faster than glycogen-accumulating organisms (GAOs). They explained this observation by comparing the growth rate of phosphorus-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) and found that pH has little effect on PAOs growth rate but adversely affects GAOs growth rate when it increases (at pH …

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Heuristic Prioritization Of Emergency Evacuation Staging To Reduce Clearance Time, Steven Mitchell Jan 2006

Heuristic Prioritization Of Emergency Evacuation Staging To Reduce Clearance Time, Steven Mitchell

Electronic Theses and Dissertations

A region's evacuation strategy encompasses a variety of areas and needs. Primary among these is the minimization of total evacuation time, represented in models as the clearance time estimate (CTE). A generic testbed simulation network model was developed. An input/output (I/O) analysis was performed to establish a theoretical baseline CTE. Results were compared with simulations; analysis showed that the I/O method underestimated simulated CTE as a function of network size, with a correction factor range of 1.09 to 1.19. A regression model was developed for the generic network. Predictors were total trips, and network size defined as a function of …

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Safety Analyses At Signalized Intersections Considering Spatial, Temporal And Site Correlation, Xuesong Wang Jan 2006

Safety Analyses At Signalized Intersections Considering Spatial, Temporal And Site Correlation, Xuesong Wang

Electronic Theses and Dissertations

Statistics show that signalized intersections are among the most dangerous locations of a roadway network. Different approaches including crash frequency and severity models have been used to establish the relationship between crash occurrence and intersection characteristics. In order to model crash occurrence at signalized intersections more efficiently and eventually to better identify the significant factors contributing to crashes, this dissertation investigated the temporal, spatial, and site correlations for total, rear-end, right-angle and left-turn crashes. Using the basic regression model for correlated crash data leads to invalid statistical inference, due to incorrect test statistics and standard errors based on the misspecified …

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Development Of A Simplified Finite Element Approach For Frp Bridge Decks., Jignesh Vyas Jan 2006

Development Of A Simplified Finite Element Approach For Frp Bridge Decks., Jignesh Vyas

Electronic Theses and Dissertations

Moveable bridges in Florida typically use open steel grid decks due to the weight limitations. However, these decks present rideability, environmental, and maintenance problems, for they are typically less skid resistant than a solid riding surface, create loud noises, and allow debris to fall through the grids. Replacing open steel grid decks that are commonly used in moveable bridges with a low-profile FRP deck can improve rider safety and reduce maintenance costs, while satisfying the strict weight requirement for such bridges. The performance of the new deck system, which includes fatigue and failure tests were performed on full-size panels in …

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Using Augmented Reality For Studying Left Turn Maneuver At Un-Signalized Intersection And Horizontal Visibility Blockage, Ghada Moussa Jan 2006

Using Augmented Reality For Studying Left Turn Maneuver At Un-Signalized Intersection And Horizontal Visibility Blockage, Ghada Moussa

Electronic Theses and Dissertations

Augmented reality "AR" is a promising paradigm that can provide users with real-time, high-quality visualization of a wide variety of information. In AR, virtual objects are added to the real-world view in a real time. Using the AR technology can offer a very realistic environment for driving enhancement as well as driving performance testing under different scenarios. This can be achieved by adding virtual objects (people, vehicles, hazards, and other objects) to the normal view while driving in a safe controlled environment. In this dissertation, the feasibility of adapting the AR technology into traffic engineering was investigated. Two AR systems; …

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Simulation And Continuance Of Operation For The Use Of Transit (Lynx) To Be Used In Emergency Evacuation Incidents, Noor Elmitiny Jan 2006

Simulation And Continuance Of Operation For The Use Of Transit (Lynx) To Be Used In Emergency Evacuation Incidents, Noor Elmitiny

Electronic Theses and Dissertations

The evacuation planning has become an important issue addressed by many research studies and publications aiming to improve the security of the daily life for our public inside the United States of America. The main objective of this research was to address the growing need for evacuation planning using traffic simulation. With increased interests and awareness in emergency evacuation and first responder access to emergencies in public locations (airports, transit stations, ports or stadiums), the traffic simulation can be helpful in orchestrating the traffic flow during emergencies. Related to this issue, Federal Transit Administration has issued a large number of …

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Verification Of Faa's Emissions And Dispersion Modeling System (Edms), Anjoli Martin Jan 2006

Verification Of Faa's Emissions And Dispersion Modeling System (Edms), Anjoli Martin

Electronic Theses and Dissertations

Air quality has been a major environmental concern for many years. Recently the issue of airport emissions has presented growing concerns and is being studied in much more depth. Airport emissions come from a variety of point, line and area sources, making emissions modeling for airports very complex and more involved. Accurate air quality models, specific to airport needs, are required to properly analyze this complex array of air pollution sources created by airports. Accurate air quality models are needed to plan for increased growth of current airports and address concerns over proposed new ones. The Federal Aviation Administration's (FAA) …

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Effects Of Fiber And Lithium On Mechanical Properties Of Concrete Made Fromrecycled Concrete Aggregate, Ashraf Eskander Jan 2006

Effects Of Fiber And Lithium On Mechanical Properties Of Concrete Made Fromrecycled Concrete Aggregate, Ashraf Eskander

Electronic Theses and Dissertations

The growing demand of construction aggregates has raised concern about the availability of natural aggregates. Over two billion tons of natural aggregate are produced each year in the United States and that number is expected to increase to 2.5 billion tons by 2020. This has raised concern about the availability of natural aggregate. Discarding demolished concrete into landfills is a costly solution from an economical and environmental point of view. Many U.S. highway agencies are re-using Recycled Concrete Aggregates (RCA) as construction material. The use of fiber reinforcement in Portland Cement Concrete (PCC) has recently become a popular option in …

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Safety Effects Of Traffic Signal Installations On State Road Intersections In Northeast Florida, Christopher Ledew Jan 2006

Safety Effects Of Traffic Signal Installations On State Road Intersections In Northeast Florida, Christopher Ledew

Electronic Theses and Dissertations

The purpose of this thesis is to explore how the installations of traffic signals affect crash experience at intersections, to identify those factors which help predict crashes after a signal is installed, and to develop a crash prediction model. It is the intent of this thesis to supplement the Manual on Uniform Traffic Control Devices Signal Warrant procedure and aid the traffic engineer in the signal installation decision making process. Crash data, as well as operational and geometric factors were examined for 32 state road intersections in the northeast Florida area before and after signal installation. Signal warrant studies were …

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Coupling Of Hydrodynamic And Wave Models For Storm Tide Simulations: A Case Study For Hurricane Floyd (1999), Yuji Funakoshi Jan 2006

Coupling Of Hydrodynamic And Wave Models For Storm Tide Simulations: A Case Study For Hurricane Floyd (1999), Yuji Funakoshi

Electronic Theses and Dissertations

This dissertation presents the development of a two-dimensional St. Johns River model and the coupling of hydrodynamic and wave models for the simulation of storm tides. The hydrodynamic model employed for calculating tides and surges is ADCIRC-2DDI (ADvanced CIRCulation Model for Shelves, Coasts and Estuaries, Two-Dimensional Depth Integrated) developed by Luettich et al. (1992). The finite element based model solves the fully nonlinear shallow water equations in the generalized wave continuity form. Hydrodynamic applications are operated with the following forcings: 1) astronomical tides, 2) inflows from tributaries, 3) meteorological effects (winds and pressure), and 4) waves (wind-induced waves). The wave …

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Developing Microscopic Toll Plaza Model Using Paramics, Nezamuddin Nezamuddin Jan 2006

Developing Microscopic Toll Plaza Model Using Paramics, Nezamuddin Nezamuddin

Electronic Theses and Dissertations

Simulation modeling is the most cost-effective way of studying real life transportation problems, either existing or anticipated, without disturbing the balance of the transportation system. There is a vast suite of simulation models available in market, ready to choose from macroscopic, mesoscopic, or microscopic in nature, to study different transportation system elements like freeways, highways, signalized and un-signalized intersections. However, most of these network simulation models, like PARAMICS, VISSIM, CORSIM … etc, do not come readily available with built in toll plaza models. On the other hand, many researchers have independently developed toll plaza models, which can only model an isolated …

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Bench Scale Analysis Of Experimental Fouling-Resistent Low Pressure Reverse Osmosis Membranes Using High Organic Surface Water And Synthetic Colloidal Water, Matthew Doan Jan 2006

Bench Scale Analysis Of Experimental Fouling-Resistent Low Pressure Reverse Osmosis Membranes Using High Organic Surface Water And Synthetic Colloidal Water, Matthew Doan

Electronic Theses and Dissertations

The utilization of membrane treatment for the production of potable water has become more prevalent in today's industry. As drinking water regulations become more stringent this trend is expected to continue. Widespread use is also a result of membrane treatment being the best available treatment in many cases. While membrane treatment is a proven technology that can produce a consistently superior product to conventional treatment methods, membrane fouling and concentrate disposal are issues that drive up the cost of membrane treatment and can effectively eliminate it from consideration as a treatment alternative. This research focused on membrane fouling. A series …

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