Digital Commons Network^™

A Decision Model For Choosing Among Photovoltaic Technologies To Generate Electricity At Grid-Connected Air Force Facilities: A Value-Focused Approach, Mostyn O. Kellner

Theses and Dissertations

The United States is currently consuming fossil fuels faster than natural processes can replace them. Our nation's leaders recognize that a diverse energy portfolio including renewable energy is the key to maintaining our economy, security, and the environment. The federal government is by far the greatest energy consumer; thus, our nation's leaders have directed federal agencies to strive to increase the use of renewable energy at federal facilities. Solar electricity technologies, in the form of photovoltaics, have great potential in the renewable energy mix. Although a major strategy should be integrating photovoltaics into the design of new facilities, an important …

Normalizing The Cpt For Overburden Stress, Robb E.S. Moss, Raymond B. Seed, Richard S. Olsen

Civil and Environmental Engineering

Effective overburden stress can have a significant influence on cone penetration test (CPT) measurements. This influence can lead to an incorrect assessment of soil strength/resistance for such purposes as liquefaction triggering analysis. For an accurate measurement of tip and sleeve resistance, unbiased by overburden stress, it is essential to normalize these index measurements appropriately. Presented herein is a comprehensive study reviewing all aspects of CPT normalization. A result of this study is a variable normalization procedure for the CPT that is based on both empirical results and theoretical analysis. This paper presents these results in the form of an improved …

Atms Implementation System For Identifying Traffic Conditions Leading To Potential Crashes, Mohamed Abdel-Aty, Anurag Pande

Civil and Environmental Engineering

Predicting a crash occurrence is the key to traffic safety. Real-time identification of freeway segments with high crash potential is addressed in this paper. For this study, historical crashes and corresponding traffic-surveillance data from loop detectors were gathered from a 36-mi corridor of Interstate 4 for 4 years. Following an exploratory analysis, two types of logistic-regression models (i.e., simple and multivariate) were developed. It was observed that, although the simple models have the advantage of being tolerant in their data requirements, their classification accuracy was inferior to that of the final multivariate model. Hence, the simple models were used to …

Long-Term Mechanical Behavior Of Yucca Mountain Tuff And Its Variability, Jaak J.K. Daemen, Lumin Ma, Guohua Zhao

Publications (YM)

The study of the long term mechanical behavior of Yucca Mountain tuffs is important for several reasons. Long term stability of excavations will affect accessibility (e.g. for inspection purposes), and retrievability. Long term instabilities may induce loading of drip shields and/or emplaced waste, thus affecting drip shield and/or waste package corrosion. Failure of excavations will affect airflow, may affect water flow, and may affect temperature distributions. The long term mechanical behavior of “hard” rocks remains an elusive topic, loaded with uncertainties. A variety of approaches have been used to improve the understanding of this complex subject, but it is doubtful …

Using Value-Focused Thinking To Evaluate The Practicality Of Porous Pavement Parking Areas On Air Force Installations, Christopher D. Bulson

Theses and Dissertations

Natural runoff processes have been altered by urban development; impervious surfaces (rooftops, highways, parking areas) and their associated storm water systems channel runoff from a vast area into one concentrated outflow. This storm water runoff can cause erosion, flooding, landslides, and significant damage to aquatic ecosystems. Runoff from highways and parking areas has also been known to contain high levels of suspended solids, heavy metals and hydrocarbons. Porous pavements allow infiltration of water through typically impervious surfaces, reducing storm water volumes and acting as a pollutant filtration system. Since there is currently no methodology for Air Force decision-makers to compare …

Analysis Of Bacterial Population And Distribution In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Bioremediation, Milton J. Clausen Jr.

Theses and Dissertations

Chlorinated hydrocarbons and their degradation products are among of the most common organic groundwater contaminates in the United States. These compounds attack the central nervous system in animals and can affect the photosynthesis of plants. These compounds are also resistant to degradation in the environment and, because of this, pose a risk to any ecosystem in which they are present. This study identified the dominant microbial species in a constructed treatment wetland at Wright-Patterson AFB, Dayton, Ohio using 16S rRNA gene sequence analysis. Samples were taken from three different depths and during each of the four seasons. These samples were …

Estimating Required Contingency Funds For Construction Projects Using Multiple Linear Regression, Jason J. Cook

Theses and Dissertations

Cost overruns are a critical problem for construction projects. The common practice for dealing with cost overruns is the assignment of an arbitrary flat percentage of the construction budget as a contingency fund. This research seeks to identify significant factors that may influence, or serve as indicators of, potential cost overruns. The study uses data on 243 construction projects over a full range of project types and scopes gathered from an existing United States Air Force construction database. The author uses multiple linear regression to analyze the data and compares the proposed model to the common practice of assigning contingency …

Baseline Modeling Of The Owensboro Cable-Stayed Bridge Over The Ohio River, Jindong Hu, Issam E. Harik, Suzanne Weaver Smith, Jeff Gagel, Jennie E. Campbell, R. Clark Graves

Kentucky Transportation Center Research Report

This report presents the baseline modeling of the Owensboro cable-stayed bridge which connects Owensboro, Kentucky and Rockport, Indiana over the Ohio River. The objective of this study is to establish the bridge baseline model via the dynamics-based technique and finite element method. The scope of research includes finite element modeling and modal analysis, field free vibration testing, finite element model calibration using field test results, and cable dynamic testing and modeling. It is demonstrated that a cable-stayed bridge is a highly pre-stressed structure. The stress stiffening of cable elements plays an important role in both static and dynamic analysis. The …

Analyzing Dynamic Characteristics Of Internal Solitons Generated At The Columbia River Plume Front With Sar Images, David A. Jay, Jiayi Pan, R. D. Brodeur

Civil and Environmental Engineering Faculty Publications and Presentations

The Columbia River plume transports dissolved and particulate load, phyto- and zooplankton,and larvae across the shelf. It also facilitates primary production and influences food-web structure through its supply of silicate and micronutrients. Small-scale phenomena such as plume fronts and internal waves generated by the plume can greatly affect vertical mixing between the plume and ocean waters. Internal waves that are generated at the front of the river plume and propagate off shoreward [Nash and Moum 2005; Orton and Jay 2005] both cause mixing and transport plume water into the adjacent coastal ocean. We use Synthetic Aperture Radar (SAR) images and …

Value Of Research From 2000-2005: The Kentucky Spr Program For Highway Research, Donald L. Hartman

Kentucky Transportation Center Research Report

The abstracts of the 79 SPR reports completed by KTC researches for 2000-2005 were compiled. Seven projects were selected for value review to demonstrate the various types of benefits that accrue from SPR project research. This review compared objectives with results and described the nature of the benefits (some quantifiable). All of the projects were analyzed to determine: 1) the Kentucky Transportation Cabinet (and FHWA) goals supported and 2) the types of benefits that would reasonably be expected to accrue from implemented results of the research. Most of the 79 projects; results address both improving the performance of the Cabinet …

Correlating Factors Between Student Participation And Student Learning Via A Service Learning Project In Secondary Education: A Case Study, Shawn V. Jensen

Theses and Dissertations

In this study a service-learning project was conducted with secondary students in a construction technology based course. Three research questions were considered; (1) does service learning projects help to engage student participation, (2) can students learn the course curriculum while participating in a service learning project, and (3) is there a correlation between student participation and student learning as it pertains to service learning projects? The data was collected through surveys, observations, interviews, and evaluations. The researcher concluded the following from the study; 92% of the students were actively participating in the two week service project, 76% of the students …

Optimal Management Of Groundwater Over Space And Time, Nicholas Brozovic, David L. Sunding, David Zilberman

Daugherty Water for Food Global Institute: Faculty Publications

For nearly half a century, groundwater has been portrayed in the economic literature as a typical common property resource. Numerous studies of groundwater extraction have analyzed the externalities imposed by users on each other. A large body of work offers clear prescriptions in the form of optimal policy instruments, and a similarly large body of work advocates the needlessness of any centralized intervention. Yet existing theoretical models of groundwater extraction implicitly make two strong assumptions about the underlying behavior of the resource. First, the spatial distribution of resource users is assumed to be irrelevant. Second, path-independence of the resource is …

Transient Heat Partition Factor For A Sliding Railcar Wheel, T C. Kennedy, C Plengsaard, Robert F. Harder

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

During a wheel slide the frictional heat generated at the contact interface causes intense heating of the adjacent wheel material. If this material exceeds the austenitising temperature and then cools quickly enough, it can transform into martensite, which may ultimately crack and cause wheel failure. A knowledge of the distribution of the heat partitioned into the wheel and the rail and the resulting temperature fields is critical to developing designs to minimize these deleterious effects. A number of theoretical solutions have appeared in the literature to model the thermal aspects of this phenomenon. The objective of this investigation was to …

Bridge Dynamics And Loading, Colin C. Caprani, Eugene O'Brien, Arturo Gonzalez, Yingyan Li, Paraic Rattigan, Niall Harris

Conference papers

Recent UCD research on dynamic bridge-truck interaction and bridge traffic loading in general is reported. The accuracy of bridge traffic load assessment has been significantly improved by identifying the differences in the sources of traffic loading on short- to medium-span bridges and treating them separately. It is shown that results can be significantly improved by treating 1-,2-,3- and 4-truck loading events separately. Gaps between trucks are also identified as a critical issue that strongly influences the frequency of key3-and 4-truck events. Trends in the dynamics of traffic loading are identified using simple force models on simply supported beams. It is …

Estimating Risk Of Failure Of Engineering Structures Using Predictive Likelihood, Colin C. Caprani, A. Bordallo-Ruiz, E. J. O'Brien

Conference papers

It has been common engineering practice to define characteristic values for loading and capacity of structures in order to assess the structural capacity of existing structures. This approach, yet practical and intuitive, lead to the comparison of deterministic values (characteristic values) that had to represent all the variability of the problem and is considered to be conservative, as usually loading is overestimated and capacity underestimated, yielding to calculations with high safety margins for the extreme events. Probabilistics methods have tried to overcom e this limitation by computing the overall probability of failure (Pf) for the lifetime of the structure, taking …

A Derivation Of An Empirical Equation For Estimating The Acoustical Shadow Zone Length Of Roadway Noise Barriers, Wayne Arner

Electronic Theses and Dissertations

The objective of this research was to derive an empirical equation that estimates the acoustical shadow zone length (SZL) of roadway noise barriers. The acoustical shadow zone is the area behind a noise barrier of reduced sound levels, generally to some stated level at or near background. The ability to predict the SZL can be used as a method to evaluate the performance, and possibly the design, of roadway noise barriers. The current federally required roadway noise model is the Federal Highway Administration (FHWA) Traffic Noise Model (TNM). TNM uses insertion loss (IL) to evaluate the effectiveness of a barrier. …

The Fathead Minnow In Aquatic Toxicology: Past, Present And Future, Gerald T. Ankley, Daniel L. Villeneuve

United States Environmental Protection Agency: Publications

This paper reviews the roles of the fathead minnow (Pimephales promelas) as a small fish model in the field of aquatic toxicology. The species has been (and is) extensively used both for regulatory testing and research, especially in North America. For example, tests with the fathead minnow, ranging from 48-h lethality through partial and full life-cycle assays, are routinely used for regulatory programs aimed at assessing potential risks of new chemicals such as high-production volume materials and pesticides, as well as impacts of complex mixtures like effluents. The species also has been used for a wide variety of …

A New Approach To Identify The Expected Crash Patterns Based On Signalized Intersection Size And Analysis Of Vehicle Movements, Hari Salkapuram

Electronic Theses and Dissertations

Analysis of intersection crashes is a significant area in traffic safety research. This study contributes to the area by identifying traffic-geometric characteristics and driver demographics that affect different types of crashes at signalized intersections. A simple methodology to estimate crash frequency at intersections based on the size of the intersection is also developed herein. First phase of this thesis used the crash frequency data from 1,335 signalized intersections obtained from six jurisdictions in Florida, namely, Brevard, Seminole, Dade, Orange, and Hillsborough Counties and the City of Orlando. Using these data a simple methodology has been developed to identify the expected …

Analysis Of Various Car-Truck Crash Types Based On Ges And Fars Crash Databases Using Mutlinomial And Binary Logit Model, Kranthi Kiran Mannila

Electronic Theses and Dissertations

Each year about 400,000 trucks are involved in motor vehicle crashes. Crashes involving a car and truck have always been a major concern due to the heavy fatality rates. These types of crashes result in about 60 percent of all fatal truck crashes and two-thirds of all police-reportable truck crashes. Car-truck crashes need to be analyzed further to study the trends for a car-truck crash and develop some countermeasures to lower these crashes. Various types of car-truck crashes are analyzed in this study and the effects of various roadway/environment factors and variables related to driver characteristics in these car-truck crashes …

A Non-Isolated Half Bridge Buck-Based Converter For Vrm Application And Small Signal Modeling Of A Non-Conventional Two Phase Bu, Majd Batarseh

Electronic Theses and Dissertations

This dissertation is about treatment of the nonbiodegradable organic content of landfill leachate by chemical oxidation combined with biological treatment. It is divided into three parts. In the first part, ferrate was compared to Fenton's reagent for the purpose of removing non-biodegradable organic compounds from mature leachate. Oxidation conditions (time, pH, and dose) were optimized to yield maximum organic removal using two leachate samples from 20 and 12-year old solid waste cells. Results from this research demonstrated that ferrate and Fenton's reagent had similar optimum pH ranges (3-5), but different organic removal capacities, ranging from 54 to 79 % of …

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 …

Study Of Same-Lane And Inter-Lane Gvw Correlation, Bernard Enright, Eugene J. O'Brien, Colin C. Caprani

Conference papers

The methodology used is to generate a number of years of simulated traffic and to use extreme value statistics to predict more accurately the characteristic loading for a given bridge. The parameters and probability distributions used in the Monte Carlo simulation must be based on observed sample traffic data. Some previous studies have made unsubstantiated assumptions regarding correlation between the Gross Vehicle Weights (GVW) of trucks in the same lane, or between trucks in adjacent, same-direction lanes. For this paper, an extensive database of Dutch Weigh-in-Motion data is analysed. Data are collected from two same-direction lanes and are time-stamped to …

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) …

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 …

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 …

Peer Review Report 2006

United States Department of Transportation: Publications

This document is reporting findings from the research peer reviews held February 7-9, 2006 for PHMSA’s Pipeline Safety Research and Development Program. The findings and recommendations in this report derive from the scoring and comments collected from the peer review panelists.

Department of Transportation (DOT) Operating Agencies (OA) are required to begin a systematic process for peer review planning for all influential and highly influential information that the OA plans to disseminate in the “foreseeable” future.

Through the Information Quality Act, Congress directed Office of Management and Budget (OMB) to “provide policy and procedural guidance to Federal agencies for ensuring …

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, …

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 …

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 …

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 …