Engineering Commons^™

Development And Application Of Its Operations Evaluation Models (Itsoems), Gummadavelly Narasimha Murthy

USF Tampa Graduate Theses and Dissertations

Intelligent Transportation Systems (ITS) play an important role in supporting motorists and first responders to handle major incidents, hazmat spills, security measures and other emergency operations. Increasingly, technology advancements and applications are providing invaluable integration opportunities to interconnect safety, maintenance, ITS, traffic operations, facilities, and transportation equipment programs to maximize available resources and achieve efficiency in transportation operations.

This research focuses on one of the prominent ITS devices: Dynamic Message Signs (DMS) operations. Using real time incident management operations data and ITS operations data, an attempt is made to develop ITS Operations Evaluations Models (ITSOEMs) that are capable of quantifying …

Driver Mandatory Lane Change Behavior: Use Of Governing Gap In Critical Gap Estimation, Srinadh Kandada

Masters Theses

"This study analyzed the driver gap acceptance and rejection behavior during mandatory lane changes on a multilane freeway in congested and uncongested traffic conditions. During a lane change, drivers were more receptive to either the leading or the trailing gaps with vehicles in the target lane which governed the drivers' lane change and is termed as the governing gap. Drivers maneuvered till the governing gap was greater than the critical gap, accepted the gap and made a lane change. In this process, drivers reduced the non-governing gap to increase the length of the governing gap. The drivers as a result …

Behavior Of Advanced Innovative Materials For Improved Long-Term Bridge Performance, Wei Zheng

Doctoral Dissertations

"The dissertation is to present the investigation results and comprehensive understanding of the long-term performance and behavior of innovative construction materials. The materials are applied in bridge engineering in order to either enhance the conventional materials or replace them. The dissertation consists of two major parts: structural steel coatings for corrosion mitigation and thermal behavior of concrete bridge.

In First Part, evaluation of advanced structural steel coatings was carried out through laboratory weathering tests (salt-fog resistance test and QUV weathering test), adhesion test, and electrochemical techniques. Fifteen coating systems were evaluated in this part, which covered both coating and recoating …

Nitrification Performance Of Activated Sludge Under Low Dissolved Oxygen Conditions, Guoqiang Liu

Doctoral Dissertations

"The combined effects of solids retention time (SRT) and dissolved oxygen (DO) concentration on nitrification, nitrifying bacterial communities, and aeration needs in the activated sludge process were studied. Nitrification was almost completed in the 10, 20, and 40-day SRT reactors with a minimum DO of 0.37, 0.25, and 0.16 mg/L, respectively. Under long-term low DO conditions, the endogenous decay of nitrifiers was slowed down and then nitirfier biomass concentration increased, thereby reducing the adverse effect of low DO on nitrification. Under long-term low DO conditions, the oxygen affinity of nitrite-oxidizing bacteria (NOB) increased significantly and as a result, NOB became …

Shear And Fracture Behavior Of High-Volume Fly Ash Reinforced Concrete For Sustainable Construction, Carlos Andres Ortega Ordonez

Doctoral Dissertations

"Concrete is the most widely used man-made material on the planet. Unfortunately, producing Portland cement generates carbon dioxide (a greenhouse gas) at roughly a pound for pound ratio. High-volume fly ash (HVFA) concrete- concrete with at least 50% of the cement replaced with fly ash - offers a potential "green" solution. However, because it is still relatively new and has some disadvantages, there are still many questions that need to be answered. Most research to date has consisted only of the evaluation of the strength and durability of HVFA concrete mixtures, while only a limited number of studies have implemented …

A Progressive Collapse Evaluation Of Steel Structures In High Temperature Environment With Optical Fiber Sensors, Ying Huang

Doctoral Dissertations

"In the process of a progressive failure of steel structures in a post-earthquake fire, real-time assessment and prediction of structural behaviors are of paramount significance to an emergency evacuation and rescue effort. However, existing measurement technologies cannot provide the needed critical data such as large strains at high temperature. To bridge this gap, a novel optical fiber sensor network and an adaptive multi-scale finite element model (FEM) are proposed and developed in this study. The sensor network consists of long period fiber gratings (LPFG) sensors and extrinsic Fabry-Perot interferometer (EFPI) sensors or their integration. Each sensor is designed with a …

Characterization Of Expanded Polystyrene (Eps) And Cohesive Soil Mixtures, Nicholas Thomas Rocco

Doctoral Dissertations

"Soils modified with expanded polystyrene (EPS) particulates could be used as lightweight fill in a variety of installations including slopes for improved stability, embankments over compressible soils, and to reduce earth pressures next to structures. The addition of low density EPS particulates into soil has a large effect on the mass and volumetric characteristics of these mixtures and their influence on mechanical properties is scarce in the literature. A laboratory characterization program using clay mixed with EPS particulates was conducted for different dosages of EPS. Soils were modified with up to 1.5% EPS by mass, which corresponds to approximately 45% …

Discrete Fiber-Reinforced Polyurea Systems For Infrastructure Strengthening And Blast Mitigation, Natalia L. Carey

Doctoral Dissertations

"The research presented in this dissertation focused on evaluating the effectiveness of various blast mitigation materials and coating technologies to be used for enhancing blast resistance of structural members. Mechanical properties and blast mitigation performance of different discrete fiber-reinforced polyurea (DFRP) systems were investigated through experimental and analytical work. Four technical papers discuss the research efforts conducted within this dissertation.

The first paper examined the development and characterization of different DFRP systems for infrastructure strengthening and blast retrofit. The behavior of various systems which consisted of chopped E-glass fibers discretely integrated in with the polyurea matrix was evaluated through coupon …

Modeling Large-Truck Involved Crashes: An Econometric Modeling Framework, Mouyid Islam

Open Access Theses & Dissertations

This research aims to analyze large-truck involved crashes (i.e., having a gross vehicle weight rating more than 10,000 pounds) through the application of advanced econometric modeling techniques--namely, random parameter models (i.e., tobit regression, mixed logit). To achieve this, various national and state specific data sets are analyzed with the goal to provide an improved understanding of the complex interactions of contributing factors (e.g., factors related to drivers and occupants, vehicle, and road-environment) influencing large-truck crashes. Additionally, the modeling techniques considered in this research account for possible unobserved effects related to the data. The aforementioned econometric techniques provide an analytical foundation …

Alternatives To Piloting In Bracksih Waters: Accuracy And Precision Of Commerical Reverse Osmosis Membrane Design Model Projections, Erika Mancha

Open Access Theses & Dissertations

In a time of economic recession and drought, the Texas Water Development Board is reviewing alternatives to the current Texas Commission on Environmental Quality requirement of demonstration-scale pilot testing membrane desalination to decrease permitting costs and project construction delays. One alternative is to use engineering judgment with membrane manufacturer's software models to predict membrane performance and ensure that product water quality requirements will be met. To comply with state permitting requirements, the first few months of successful full-scale operation can be submitted in lieu of pilot demonstration.

The goal of this research is to characterize the accuracy and precision of …

Development Of Models To Estimate Modulus And Permanent Deformation Of Texas Bases, Eric Navarro

Open Access Theses & Dissertations

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Investigation Of Gas-Solid Fluidized Bed With Non-Spherical Particles, Mario Alberto Ruvalcaba

Open Access Theses & Dissertations

The number of experimental and numerical studies of multiphase flows has remarkably increased over the last several years. This research has abundant applications in energy, chemical, and conversion processes. Common use of these technologies includes catalytic cracking for petroleum refineries, fluidized bed reactors (type of chemical reactor), interface modification, and has been an important technology breakthrough in coal gasification. The present work will concentrate on the investigation and validation of gas-solid flows utilizing numerical methods. The gas-solid flows study on this research assumes the solid and gas phases as continua with averaged properties.

The fluid flow computation was achieved using …

Comparison Study Between Fem And Sem For Wave Propagation Models Applied To Solids, Shaddy Roberto Castillo Ponton

Open Access Theses & Dissertations

Wave propagation is a field whose application has spread across many disciplines. In the field of structural engineering, wave propagation methods have focused their attention specifically in the area of structural health monitoring and active control of vibrations and noise. Likewise, the development of new methods and their application have been successful in the area of material science with a special emphasis on the field of structural integrity evaluation of anisotropic and inhomogeneous structures (laminated composite structures). The current available analysis tools are inadequate to handle the modeling of complex structures. One-dimensional wave propagation problems in solids are still a …

Vulnerability Of Intermodal Logistic Networks To Sea Port Disruption, Jana Cervinska

Open Access Theses & Dissertations

Maritime trade is the backbone of international trade, specifically seaports which provide the gateway for the shipping and receiving of all international goods. Any disruption in operation can trickle down the global supply chain increasing costs and delay delivery of supplies. Hence, the objective of this work is the formulation of optimization models to study the vulnerability of intercontinental ports. Experiments are applied to container transportation between U.S. and Europe. The work differentiates itself from previous studies in that we analyze the vulnerability of the sea ports and compare how the closing of some ports or liner shipping lanes influence/impact …

Methodologies For The Analysis Of Checked Baggage Inspection Systems, Nela Blejcharova

Open Access Theses & Dissertations

To enhance the security of the aviation system it is necessary to have a Checked Baggage Inspection System (CBIS) that is effective (that is, the highest possible detection probability or minimum false clear probability) yet efficient (that is, minimize the false alarm probability that causes inconvenience to passengers).

The first objective of this thesis is to review passenger, carry-on and checked baggage inspection procedures at airports

The second objective of this thesis is to develop a methodology using the optimization approach to set the optimal values of the sensitivity of the screening devices to minimize the total cost of inspecting …

Systematic Approach To Evaluate Potential Park And Ride Facilities, Lorenzo Emanuel Cornejo

Open Access Theses & Dissertations

Park and Ride (P&R) facilities promote transit ridership by providing an attractive option to car drivers. They enable potential users to drive to their locations where they can park their cars and take transit services to complete their destinations.

Although the concept of P&R has been implemented in many cities in the United States and integrated with different transportation modes such as mass rapid transit (MRT), light rail transit (LRT), high occupancy vehicle (HOV), Bus Rapid Transit (BRT), among others, no systematic approach has been developed to assess the feasibility of a potential P&R facility. This thesis proposes a systematic …

Calibration Of Concrete Pavement Performance Models, Alejandra Gallegos

Open Access Theses & Dissertations

Pavement performance models exist in various forms to cater to the pavement management agencies' needs and resources. Well-calibrated models are needed to accurately predict future pavement conditions, and to forecast and prioritize confidently the future rehabilitation and maintenance expenditures. Statistical tools are commonly used to develop the performance models. These statistical models may be impractical or misleading if not constrained with experts' opinions. This paper presents a hybrid technique where statistical tools and expert knowledge are combined for the calibration of pavement performance models. This technique was validated using historical pavement condition data for continuously-reinforced-concrete pavements (CRCP) from the Texas …

Carrier Collaborative Networks: Hybrid Hub Location Algorithms, Satyen Suresh Awale

Open Access Theses & Dissertations

Within the context of the Logistics and supply chain and management, the Hybrid Hub and Spoke system has certain complexities regarding the selection of the hub location in the supply chain facility system. The performance and efficiency of the network route selection and hub location depends upon the percentage savings that has been made by choosing the appropriate location for the hub to maintain the efficient flow of the goods within the network. Hub location selection mostly depends on the profit margins shared by the carrier, supply and demand status of the facility and amount of flow of the goods …

Sustainable Disposal Of Brine, Bijoy Krishna Halder

Open Access Theses & Dissertations

To meet growing water demand, more water is being harvested from nontraditional sources like brackish water from deep underground aquifers. Since these sources contain salts, drinkable water is produced by separating salt and other minerals (TDS, Total Dissolved Solids) from water through a process commonly known as desalination. A typical desalination plant produces 50-60% potable water from brackish water and the remaining water (brine) is disposed in evaporation ponds or by injecting it below the ground surface. To maximize the limited water supply, inland desalination plants have developed technologies to reduce brine production commonly known as zero liquid discharge (ZLD) …

Analysis Of Isolated Traffic Signal Control Systems, Petr Malina

Open Access Theses & Dissertations

Intelligent Transportation Systems (ITS) are implemented for increase of efficiency and safety in transportation. This thesis focuses on the area of traffic signal timing operations which is one of ITS components. The first objective is to compare the Czech and the U.S. methods for isolated fixed time traffic signal control, using an intersection in El Paso, Texas, as the test site. The second objective of this thesis is to evaluate the U.S. actuated isolated timing plan and compare it against the Czech and U.S. fixed time controls. A microscopic traffic simulation model of the selected intersection is coded in VISSIM …

Evaluation Of Non-Nuclear Devices In Measuring Moisture Content And Density Of Soils, Martin Jesus Sotelo

Open Access Theses & Dissertations

The objective of this report was to assess the ability of several different devices to measure moisture content and dry density of various compacted geomaterials. The experimental research involved the testing of different subgrade soils and one base material. More than a dozen specimens, 2 ft in height and 1.5 ft in diameter, were constructed to evaluate the Transtech SDG 200, Purdue TDR, and the Decagon 10 HS moisture content sensor. The Speedy Moisture Tester and DOT600 Roadbed Water Content Meter were also evaluated using individual soil samples. All materials were tested at five different moisture contents, but at their …

Development Of An Electronic Vehicle Miles Travelled Toll Model, Marketa Vavrova

Open Access Theses & Dissertations

This thesis presents the reasons why the fuel tax is no longer a viable source of revenues and suggests new sources of funding. One possibility is to replace the fuel tax with a distance-based toll applied nationwide. Vehicle miles travelled (VMT) fee is compared to the fuel tax, and the relationship between road infrastructure spending and fuel taxation in the United States (U.S.) and the European Union (EU) is explored. Also the European approach to taxation and tolling is described and compared to the situation in Texas.

The development of a statewide distance-based toll model to estimate the feasibility of …

Construction Of Mse Wall Using Tire Shred-Sand Mixture As Backfill (Spr-3470), Monica Prezzi, Varenya Kumar Duvvuru Mohan

JTRP Other Publications and Reports

A large number of waste tires are generated each year throughout the world. Instead of disposing these tires in landfills, they can be used beneficially in road construction, MSE walls or structural fills that require large quantities of material. Such use of tires not only saves the costs of landfilling, but also provides certain desirable mechanical properties. The focus of this research was on determining important geotechnical properties of tire shred-sand mixtures required for their use as a lightweight backfill for MSE walls. Accordingly, the shear strength and pullout characteristics of tire shred-sand mixtures at various mixing ratios were determined …

Development Of Self-Stressing System For Bridge Application With Emphasis On Precast Panel Deck System, Marcelo Ferreira Da Silva

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Steel girder bridges often utilize continuity over the pier to reduce interior forces on the spans. In continuous structures with composite concrete decks, the location of maximum negative bending moment is over the interior supports. This moment produces tensile stresses in the concrete deck and compressive stress in the bottom flanges of the girders. The tensile stress in the deck leads to cracking which allow intrusion of moisture and road salt, causing corrosion of the reinforcement and supporting girders. Continued maintenance is required to forestall the deterioration; however, replacement of the deck is eventually required.

To overcome this problem, a …

Utilizing Technology To Increase The Recycled Content Of Asphalt Mix Designs, Nicholas Ricketts

Purdue Polytechnic Masters Theses

This directed project examined the idea that increasing the amount of recycled asphalt product in road construction will result in a comparable performance to the current levels of recycled asphalt product in today’s pavement. A critical review of literature is structured in four areas: describing the need (financial and environmental) for the increased use of recycled materials, describing how others have addressed the issue and technology needed for increasing the use of recycled content, describing how some contractors have created the technology needed, and finally describing the direction needed in order to encourage customers and government agencies to embrace the …

Virtual Microstructure Generation Of Asphaltic Mixtures, Mohammad Haft-Javaherian

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This thesis describes the development and application of a virtual microstructure generator incorporated with post-processing image analysis methods that can be used to fabricate a virtual, two-dimensional microstructure of asphaltic mixtures. In the generator, geometrical characteristics such as aggregate gradation, aggregate area fraction, angularity, orientation, and elongation were used to transform data from a three-dimensional (3D) mixture into its two-dimensional (2D) microstructure. The 2D virtual microstructures were generated from real 3D mixture information of asphaltic composites. Resulting virtual microstructures were then compared to real cross-sectional microstructure images obtained from actual samples for validation. Comparison presented a good agreement between the …

The Role Of Eddies Inside Pores In The Transition From Darcy To Forchheimer Flows, Kuldeep Chaudhary, M. Bayani Cardenas, Wen Deng, Philip C. Bennett

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

We studied the role of intra-pore eddies, from viscous to inertial flows, in modifying continuum-scale flow inside pores. Flow regimes spanning Reynolds Number Re ∼ 0 to 1350 are divided into three zones - one zone follows Darcy flow, and the other two zones describe non-Darcy or Forchheimer flow. During viscous flows, i.e., Re < 1, stationary eddies occupy about 1/5 of the pore volume. Eddies grow when Re > 1, and their growth leads to the deviation from Darcy's law and the emergence of Forchheimer flow manifested as a characteristic reduction in the apparent hydraulic conductivity K_a. The reduction in K_a is due to the narrowing of the flow channel which is …

Regeneration Of Carbon Aerogel Exhausted In Water Purification, Sanjay Tewari

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Carbon has been used electrochemically in various forms for water treatment and the carbon aerogel is one of them. Carbon Aerogels (CA) are used as electrodes due to their high surface capacity and high electrical conductivity. They are also known as Carbon Nanofoams (CNF). CA electrodes attract oppositely charged ions that are nearby. This concept is known as Capacitive De-Ionization (CDI). The use of CA in CDI for water purification is well documented, but not much work has been done on regeneration of CA electrodes. Once saturated, these electrodes lose their ability to adsorb additional ions and it must be …

The Marked Tree Site: Evaluation Of Geosynthetic Reinforcements In Flexible Pavements, Taylor Mitchell Goldman

Graduate Theses and Dissertations

This document presents findings from a three-year, full-scale, field research project aimed at determining the benefits of using geosynthetic reinforcements to improve the performance of flexible pavements constructed over poor subgrade soils. The test site, known as the Marked Tree site, is an 850-ft (258-m) long segment of low-volume frontage road along Highway 63 in the town of Marked Tree, Arkansas. The site, constructed in 2005, consists of seventeen 50-ft (15.2-m) long flexible pavement test sections with various types of geosynthetic reinforcements (woven and nonwoven geotextiles, and geogrids), which were all positioned at the base-subgrade interface, and two different nominal …

Influence Of Recycled Asphalt Shingles On Asphalt Binder Content, Mixture Stiffness, And Laboratory Rutting Performance, Joshua David King

Graduate Theses and Dissertations

Recycled asphalt shingles (RAS) is a technology in which pavement costs can be reduced significantly and pavement properties may be enhanced. Also, incorporating shingles into pavements reduces the impacts of waste shingles in landfills, preserving our environment. However, for this new technology to be practical for implementation, a better understanding of how the ground shingles affect the properties of the asphalt is necessary. The purpose of this research was to examine the effects of recycled asphalt shingles on asphalt binder content, mixture stiffness, and laboratory rutting performance. For this project, shingles were added to hot mix asphalt mixtures at 2.5, …