Digital Commons Network^™

A Proposed Framework For Simultaneous Optimization Of Evacuation Traffic Distribution And Assignment, Fang Yuan

Doctoral Dissertations

In the conventional evacuation planning process, evacuees are assigned to fixed destinations based mainly on the criterion of geographical proximity. However, such pre-specified destinations (OD table) almost always lead to sub-optimal evacuation efficiencies due to uncertain road conditions such as congestion, road blockage, and other hazards associated with the emergency. By relaxing the constraint of assigning evacuees to pre-specified destinations, a one-destination evacuation (ODE) concept has the potential of greatly improving the evacuation efficiency. A framework for simultaneous optimization of evacuation traffic distribution and assignment is therefore proposed in this study. Based on the concept of ODE, the optimal destination …

Evaluation Of Heavy-Duty Diesel Vehicle Emissions During Cold-Start And Steady-State Idling Conditions And Reduction Of Emissions From A Truck-Stop Electrification Program, James A. Calcagno

Doctoral Dissertations

Cold-start and extended-idling emissions of carbon monoxide (CO), oxides of nitrogen (NOx) and particulate matter (PM) were measured from 24, class-8B, heavy-duty diesel vehicles (HDDV8B) using portable emission monitoring equipment. The ratio of nitrogen dioxide (NO₂) to NOx and the ratio of PM_2.5 to total PM were reported. Truck model years ranged from 1992 to 2004. All vehicles were tested in the field during summer and fall months under ambient environmental conditions at low (600-800 rpm) and high (1000 rpm) engine idling speeds with the truck cab air-conditioner operating at “on” and “off” modes. Sampling data thus …

Health Risk Assessment Posed By The Mobile Source Air Toxics On An Urban To Regional Area, Luis Alonso Díaz Robles

Doctoral Dissertations

Air toxics are important health concern. The purpose of this research was to develop a protocol to predict exposure concentrations of air toxics and inhalation cancer and noncancer risk that come from different gasoline and diesel-fueled sources. The protocol was developed by linking the U.S. EPA’s Models-3/CMAQ model as the exposure model and toxicological and epidemiological evidence functions. The NEI version 3 for the year 1999 was used in this analysis for point, area, and non-road sources, whereas NMIM was used to create the on-road emissions. The year 2003 was used for meteorological data and as reference to compare the …

The Rrnat/Rdna Ratio As A Measure Of Nitrite Oxidizing Activity, Shawn A. Hawkins

Doctoral Dissertations

A bench scale nitrification reactor (BSNR) containing nitrite oxidizing bacteria (NOB) of the genus Nitrobacter (» 1 × 10¹⁰/L; 5 - 22% of bacteria) was used to assess the ribosomal RNA transcript (rRNAt) to ribosomal RNA gene (rDNA) ratio as an in-situ nitrite oxidizing activity metric. A quantitative PCR detection system was developed that amplified a 143 base pair sequence within the Nitrobacter spp. 16S - 23S intergenenic spacer region. The resulting real-time PCR (rDNA) and real-time RT-PCR (rRNAt) assays were specific, accurate, and sensitive, requiring three replicate nucleic acid extracts to reliably detect a true 2-fold concentration …

Characterizing Turbulence Structure Along Woody Vegetated Banks In Incised Channels: Implications For Stream Restoration, Frank James Dworak

Masters Theses

The impacts of urbanization have modified natural watersheds and stream hydraulic, hydrologic, and geomorphic processes that have lead to geomorphic and ecological disturbances in natural stream systems. These alterations have resulted in channel incision and the loss of channel-scale hydraulic characteristics responsible for initiating and maintaining pool-riffle bedforms, which are capable of supporting diverse biological stream ecosystems. Through the use of FLOW-3D, a 3-dimensional computational fluid dynamics model, three scenarios of an urban, incised, and channelized stream were simulated to characterize the turbulent, hydraulic structure during bankfull discharge. The simulations were conducted with trees inhibiting bankfull flow (representing the channel’s …

Linking Channel Stability And Bed Sediment Characteristics To Biological Integrity In Tennessee Ridge And Valley Streams, Kelley H. Williams

Masters Theses

Streambed sedimentation has plagued waterways since the beginning of civilization, whether as a natural flow process or human disturbances on the landscape in more recent times. Due to the continual degradation in the quantity and diversity of aquatic organisms within streams, the issue has finally surfaced as a significant concern. The need to develop better Total Maximum Daily Load (TMDL) assessment tools to link sediment impairment to biological integrity was the driving force behind this study.

Within the Ridge and Valley Ecoregion, 76 stream reaches were analyzed to investigate the impacts of stability issues and bed sediment characteristics on stream …

The Cornerstone Fall 2005, Department Of Civil & Environmental Engineering

The Cornerstone

No abstract provided.

Floating Wim Threshold Concept For Truck Weight Enforcement, Zhongren Gu

Doctoral Dissertations

Weigh stations are the primary weight compliance checkpoints for commercial trucks. In the past several decades, states have used weigh-in-motion (WIM) technology to reduce delay and increase enforcement on overweight vehicles. This study offers a detailed analysis of weigh station systems and presents floating-threshold algorithms to improve the efficiency of WIM equipped weigh stations.

This research evaluates weigh station design and operational parameters using queueing theory and found that WIM technology not only enhances the effectiveness and efficiency of weigh station operations but also largely reduces travel delay for trucking companies. The effects of truck demand, truck weight distribution, static …

Application Of Statistical Methods And Process Models For The Design And Analysis Of Activated Sludge Wastewater Treatment Plants (Wwtps), Jinsheng Huo

Doctoral Dissertations

The purpose of this study is to investigate statistical procedures to qualify uncertainty, and explicitly evaluate its impact on wastewater treatment plants (WWTPs). The goal is to develop a statistical-based procedure to design WWTPs that provide reliable protection of water quality, instead of making overly conservative assumptions and adopting empirical safety factors. An innovative Monte Carlo based procedure was developed to quantify the risk of violating effluent as a function of various design decisions. A simulation program called StatASPS was developed to conduct Monte Carlo simulations combined with the ASM1 model.

A random influent generator was developed to describe the …

Freeway Crash Prediction Models For Long-Range Urban Transportation Planning, Vasin Kiattikomol

Doctoral Dissertations

The need for safety assessment tools for long-range transportation planning was not seriously recognized until the Transportation Equity Act for Twenty First Century (TEA-21) established a requirement related to safety considerations in the planning process of Metropolitan Planning Organizations (MPO). Currently, most MPOs do not assess the safety consequences of alternative transportation systems. The goal of this dissertation is to develop practical tools for assessing safety consequences of freeways in the context of long-range urban transportation plans. Data for freeway segments and crashes were obtained from North Carolina Department of Transportation and Tennessee Department of Transportation. Three different modeling approaches …

Analytical Verification Of The Aci Approach Of Estimating Tensile Strain Capacity Of Mass Concrete, Cristina Diane Seay

Masters Theses

Mass concrete fill is being used for the support of a facility foundation in Oak Ridge, Tennessee. The facility design requires the support foundation to be relatively crack-free in order to attain the shear wave velocity of 6000 fps, which is necessary for acceptable structural behavior during a design basis earthquake. Specifications were developed for use during construction of the support foundation to ensure that the mix design, sequential placement, and curing are performed to standards that would best ensure a relatively crack-free product. The mix design and subsequent placement strategy were developed by using an American Concrete Institute (ACI) …

Evaluation Of Experimental Bridge: Massman Drive Bridge Over Interstate 40 In Davidson County, Jeremy Glen Pettus

Masters Theses

The Massman Drive Bridge is a 284ft. two-span continuous steel bridge over Interstate 40 in Nashville, TN. The bridge is an experimental design that unifies the construction economy of simple span bridges and the structural economy of continuous span bridges. The structural system involves bridge girders initially erected with simple supports at the center bent and abutments.

Before the deck is placed, an experimental connection is used to rigidly connect the two adjacent girders over the center bent. The experimental connection couples a cover plate in tension and two kicker wedge plates in compression. The kicker wedge plates supply resistance …

Modeling And Analysis Of The Dupont Access Bridge, Naiyu Wang

Masters Theses

This thesis evaluates the lateral wheel load distribution on a two-span experimental highway bridge, examines the continuity of the superstructure over the center pier, and investigates the connection between bridge girders and abutments. Simplified finite element models of the bridge superstructure with different boundary conditions were made during the research to simulate the bridge behavior and verify the field data. Live load distribution factors for moment from the model with a rotational spring connection between bridge girders and abutment correlated well with factors from field measurements, and they were compared with factors from other methods currently in use such as …

Identification Of The Microfabric Of Kaolin Clay And Its Impact On The Shear Strength Behavior, Ajanta Sachan

Doctoral Dissertations

A new method for identifying the microfabric (geometric arrangement of platelets) of cohesive soil using X-ray diffraction technique without the need for a pole figure device is introduced in this study. This method is based on identifying the occurrence of basal and prism peaks in a given X-ray diffraction pattern and their relative intensities observed in the pattern. Five different specimen preparation techniques are used to prepare the Kaolin clay specimens with different particle orientations to identify their microfabrics using X-ray diffraction analysis, and the results are assessed in conjunction with high magnification SEM (Scanning Electron Microscope) images. The proposed …

Effects Of Heavy-Duty Diesel Vehicle Idling Emissions On Ambient Air Quality At A Truck Travel Center And Air Quality Benefits Associated With Advanced Truck Stop Electrification Technology, Guenet Tilahun Indale

Doctoral Dissertations

United States Department of Transportation (DOT) requires truck drivers to rest for 10 hours after every 14 hours of driving. During this time and while waiting for loading and unloading of their trucks, truck drivers idle their engine to provide heat or air conditioning for the cab and sleeping compartment, keep the engine warm during cold climate, and provide electrical power for their onboard appliances. At large truck stops, 200 or more trucks may be idling at the same time. At these truck stops idling emissions can significantly contribute to the concentrations of NOx and PM_2.5 pollutants in the …

The Effects Of Urbanization On The Streambed Sediment Characteristics In A Ridge And Valley Watershed, Brantley Allison Thames

Masters Theses

Urbanization causes flow and sediment regime changes, which leads to alterations in the bed sediment characteristics and degradation of the ecological habitat. Evidence shows that changes in the characteristics of streambed sediment occur in urbanized watersheds; however a link between urbanization and changes in streambed sediment is not well established in the literature. Limited support in the literature does suggest that urbanization is linked to a decline in the diversity of algae, invertebrate, and fish populations. Relationships between urbanization and bed sediment characteristics were explored by three studies using the AnnAGNPS and CONCEPTS models. AnnAGNPS is a GIS-based sediment delivery …

Traffic Signal Phase Truncation In The Event Of Traffic Flow Restriction, Scott Glenn Beaird

Masters Theses

This thesis presents a proposed improvement to traffic signal controller logic. The concept consists of truncating a phase on which there is demand but zero or minimal flow due to a restriction of traffic. The logic presented in this thesis recognizes such a flow restriction and, consequently, terminates the phase in favor of a conflicting call for service. The theory of the concept is addressed and methods of implementation are explored.

An experimental analysis was conducted in order to qualify the benefit of the phase truncation concept. This analysis was conducted using the VISSIM simulation software in conjunction with a …

Modeling Of Unreinforced Construction Joints In Plain Concrete Using Gt Strudl, James Christopher Carroll

Masters Theses

The purpose of this study was to develop a method to predict the behavior of unreinforced concrete construction joints using the computer program GT STRUDL. Two three-dimensional finite element models of a navigation lock wall were constructed. The wall was subjected to eccentric prestress forces, which brought about concern for lift-off within the lock wall.

Eleven loading combinations were evaluated, which were created from seven independent loading conditions. Stresses for each loading combination were compared to nominal strength values as detennined by ACI 318-02, Chapter 22, for plain concrete. Results show the stresses to be acceptable throughout the wall and …

The Inverse Application Of Conformal Mapping Techniques To Describe Groundwater Flow-Regimes Through A Window In The Upper Claiborne Confining Layer, Patrick Lasater Mcmahon

Masters Theses

The purpose of this study was to establish an inverse algorithm to solve the analytic element groundwater modeling equations, developed by Anderson (2001), for state parameters based on head data from an appropriate field site. The analytical element model (AEM) equations developed by Anderson (2001) are a complex variable technique to describe flow regimes through a gap in a confining layer that otherwise separates two confined aquifers. Anderson’s equations are based on the assumptions that hydraulic conductivity is constant in the respective confined aquifers. It also assumes a hydraulic conductivity of zero for the confining layers in the system.

A …

Comparison Between Tapered Element Microbalance (Teom) And Federal Reference Method (Frm) For Pm2.5 Measurement In East Tennessee, David Scott Greene

Masters Theses

Particulate matter (PM) of 2.5 microns or less is linked to serious negative health and visibility effects, and consequently is gaining increased regulatory attention. Therefore, accurate and timely measurement of ambient PM_{2.5 is an essential task for both researchers pursuing productive investigations, and local air quality administrators in evaluating, modeling, planning for compliance, and generally making the highest productive use of their control resources. However, accurate and timely may be conflicting needs.}

Many studies have concluded that a significant difference in measurements exists between the Tapered Element Oscillating Microbalance Monitors (TEOM) and the Federal Reference Method (FRM). The difference …

A Comparison Between The Compressive Strength And The Dynamic Properties Of Concrete As A Function Of Time, Shane Darrel Boone

Masters Theses

The purpose of this study was to examine and compare the correlation between the compressive strength of a mass concrete mix and that concrete’s dynamic properties, specifically, shear wave velocity. Several methods, including static and dynamic tests, were used to determine the concrete’s physical properties of compressive strength, modulus of elasticity, both static and dynamic, and shear wave velocity.

It has been found that, for the specific concrete analyzed, there is a correlation between the compressive strength and dynamic properties as well as a correlation between the static and dynamic moduli. The data found in this study shows that dynamic …

An Evaluation Of Alternative Permissive Periods On Non-Coordinated Phase Performance In Coordinated Traffic Signal Systems, Manoel Mendonca De Castro-Neto

Masters Theses

Currently, there are some concerns regarding coordinated-actuated traffic signal operations. First of all, there is no consistent nomenclature to describe coordination modes. Different traffic signal controller manufacturers use different terminologies and their terms are not necessarily meaningful or intuitive. Actually, one can find inconsistency in the terminology used even by a specific manufacturer just by trying to understand (or decipher) the manual. Secondly, and this might be just a consequence of the first concern, it seems that many traffic engineers and technicians are not aware of the particularities and differences among the coordination modes.

The main purpose of this study …

Evaluation Of The Dupont Access Bridge, David Pendleton Chapman

Masters Theses

This Thesis describes the evaluation of a experimental steel connection used on the DuPont Access Bridge in New Johnsonville, Tennessee. The bridge has two spans and is designed to act continuously under the dead load. The connection consists of a tension plate bolted to the top flange of the girders at the pier and a wedge plate welded to the bottom flange of the girders. This Thesis also describes the measured and predicted lateral load distribution of the bridge.