Engineering Commons^™

Time And Frequency Domain Analyses Of Hydrologic And Stream Water Quality Data, Shesh Raj Koirala

Doctoral Dissertations

The issue of scaling of deterministic properties at various domain levels has become an area of interest for active research. Interpretation of observational data, and similarly hydrologic simulation, require an understanding of how certain deterministic modeling parameters scale from the smaller to larger domains spatially and temporally. Novel approaches to better understand scaling behavior in hydrologic systems and that will result in improved deterministic modeling are necessary to advance the state-of-the-science in hydrologic transport processes, particularly in the areas of microbial concentration and inorganic chemical constituent dynamics. Two primary objectives of this research were i) to determine the statistical relationship …

Evaluation Of Impacts On Delay, Cycle-Length Optimization, Control Types, And Peak-Hour Factor With The Randomness Of Traffic, Jan-Mou Li

Doctoral Dissertations

Some basic concepts about traffic which are correct in theory may be misinterpreted in practice. Such misinterpretations may lead to a different direction from the ideal operation. This four-part dissertation is designated to examine fundamental concepts in traffic operation, and to validate the impact of randomness on control delays, cycle-length optimization, control types, and the peak-hour factor.

Control delays experienced by drivers is a critical performance measure on interrupted-flow traffic which involves movements at slower speeds and stops on intersection approaches, as vehicles move up in the queue or slow down upstream of an intersection. Since the basic term of …

Characterizing Groundwater-Surface Water Interactions In Great Smoky Mountains National Park Using Hydrologic, Geochemical & Isotopic Data, Amanda Marie Mckenna

Masters Theses

Groundwater-surface water interactions can substantially influence the quality of surficial water bodies and are thus important when investigating ecological health of and climate change impacts on an area. However, data collection can be hindered when the location is remote and/or legally protected. This paper presents a methodology to implement minimallyinvasive field techniques at a remote and protected location that allows preliminary identification of the relationship between groundwater and surface water. Great Smoky Mountains National Park was selected as the study area as it is subjected to some of the highest rates of acid deposition in the country. Ecological damage is …

Using Multivariate Analysis Of Geochemical Data To Better Define Hydrologic Interfaces In Surface Water - Groundwater Systems, Candice Ann Owen

Masters Theses

Groundwater-surface water interactions have been shown to be important to flow generation and stream chemistry in upland catchment environments. These areas, however, are often difficult to access making the implementation of standard hydrological surface and subsurface monitoring equipment and characterization procedures impractical, arduous and in many cases impossible due to the nature of the terrain and also regulatory guidelines for protected areas. By collecting surface water samples at distinct water contribution sites to a headwater stream, areas of groundwater influence were inferred and a hydrochemical conceptual model of a small basin was created.

The objectives of this research were to …

Blast Resistant Design Of Steel Structures, Sarah Beth Janney

Masters Theses

The purpose of this study was to examine the load experienced by a steel blast cubicle from a surface blast test. An important objective was to determine the blast load experienced at different standoff distances and the blast resistance capability of the blast cubicle. Three cubicles with standoff distances of 20, 25, and 30ft respectively were simultaneously subjected to a 50lb TNT explosive. The manual Structures to Resist the Effects of Accidental Explosions, Army TM 5-1300 conservatively predicted the blast pressure loadings obtained from the pressure transducers mounted on the cubicles. Data collected from accelerometers was compared to results from …

Application Of Particulate-Filled Composite (Pfc) Theory To Hot-Mix Asphalt (Hma) Mixtures, Xiang Shu

Doctoral Dissertations

Dynamic modulus (|E*|) of HMA mixtures is one of the fundamental engineering properties measured by the Simple Performance Tester (SPT) and has been incorporated as a basic input parameter in the American Association of State Highway and Transportation Officials (AASHTO) 2002 Mechanistic-Empirical (M-E) Design Guide for flexible pavement design. Although direct laboratory testing and empirical equations (such as the Witczak model and the Hirsch model) provide two ways to obtain the values of dynamic modulus of HMA mixtures, a predictive model based on the microstructure of HMA mixtures is more desirable.

HMA mixtures consist of three phases: aggregate, …

Study On Infrastructure Materials Using Neutron Radiography And Diffraction, Xin Luo

Doctoral Dissertations

Advanced nondestructive neutron technology has been utilized to study fundamental issues in the Lost Foam Casting (LFC) process and in the mechanical behavior of infrastructure materials.

Time lapsed neutron radiography combined with digital image processing was used to investigate the real-time LFC process. Behavior and characteristics of the pyrolysis front in the LFC processes were discussed. Evidence shows that neutron radiography offers new insights into the pyrolysis front and the dynamics of the processes involved with the casting. Behavior and characteristics of the pyrolysis front and the molten metal interface in the LFC processes were revealed. The proposed approach will …

Physiological Stress In Native Brook Trout (Salvelinus Fontinalis) During Episodic Acidification Of Streams In The Great Smoky Mountains National Park, Keil Jason Neff

Masters Theses

Episodes of stream acidification are suspected to be the primary cause of the extirpation of native southern brook trout (Salvelinus fontinalis) from six headwater streams in the Great Smoky Mountains National Park (GRSM). During periods of increased flow from storm events, stream pH can drop below 5.0 (minimum of 4.0) for 2-days or longer. To provide evidence that native brook trout are impacted by stream acidification, in situ bioassay experiments were conducted. Changes in stream water chemistry and brook trout physiology were determined during a 36-hour acidic episode at three remote headwater stream sites in the Middle Prong of the …

Evaluation, Comparison, And Design Of Two Experimental Bridges In Tennessee, Kyle Parker Scoble

Masters Theses

This thesis describes the design and evaluates the adequacy of the moment connection of an experimental two-span highway bridge designed by the Tennessee Department of Transportation. The Massman Drive bridge is an experimental design that unifies the construction economy of simple span bridges and the structural economy of continuous span bridges. The experimental connection, consisting of cover plates and kicker wedge plates, is used to connect the two adjoining girders over the center pier. As a result, the bridge is designed to function as a continuous bridge during the deck pour and behave compositely with the reinforced concrete deck under …

“Parametric Study Of The Effects Of Water To Cementitious Materials Ratio And Cementitious Materials Content On The Durability Properties Of High Performance Concrete, Andrew T. Tinsley

Masters Theses

This study takes a detailed look at the factors that affect the durability of concrete and how they can be applied to the development of a useful performance specification and help to extend the life of bridge decks and other concrete structures exposed to the elements of nature. A series of fifteen mixes (with varying cement contents and water/cement ratios) were performed in order to determine exactly which of these factors have a significant effect on the durability of a concrete mix. Controlling the water/cement ratio is necessary in order to control strength and permeability. Cement content was found to …

Modeling The Quorum Sensing Signaling Regulatory Network In Vibrio Fischeri, Ling Yan

Doctoral Dissertations

Quorum sensing is a mechanism by which bacteria can sense the levels of signaling molecules and respond by controlling the expression of target genes. The marine bacterium, Vibrio fischeri, has been extensively studied as a model for the quorum sensing mechanism in Gram-negative bacteria. In order to systematically investigate the quorum sensing regulatory network in V. fischeri, a conceptual model was first established based on the existing knowledge. Next, molecular microbiology and bioinformatics techniques were employed to both qualitatively and quantitatively characterize the system. These techniques included the quantification of the 3-oxo-C6-HSL concentrations in the cell culture supernatant …

Commerical Vehicle Enforcement Using License Plate Recognition Technology, Stephanie R. Hargrove

Masters Theses

Speed limits for large trucks have been reduced at many locales for air quality and safety reasons. To realize an improvement in air quality and safety, however, diligent enforcement and fitting punishment have to be implemented. This may put a strain on already tight resources and manpower for state and local agencies. To this end, this paper presents a license plate recognition (LPR) technology based heavy vehicle speed enforcement system that requires relatively minimal initial investment and no increase in enforcement personnel, cruisers, or pursue/pull-over activities. The efficiency of the system is achieved by catching speeding trucks in the act …

Determination Of Air Flotation Parameters To Perform Solid Liquid Separation Treatment In An Activated Sludge Treating Grease Waste By Promoting Filamentous Bacteria, Juan Guillermo Cartajena Torrealba

Masters Theses

The focus of this investigation was the determination of air flotation parameters to perform solid liquid separation treatment in an activated sludge treating grease waste by promoting filamentous bacteria. The treatment was intended to achieve a pretreatment level, previous to the application of the typical activated sludge process.

Generally solid liquid separation in activated sludge is performed by gravitational settling, but it is been demonstrated that the presence of an overgrowth population of filamentous microorganism in activated sludges hinder the settling properties of it. For this reason, gravitational settling may result in an inefficient treatment. Therefore, an alternative treatment has …

Experimental Investigation Of Reinforced Concrete Beams With Lapped Reinforcement, Mary Elizabeth Griffey

Masters Theses

One of the great contributions made by President Dwight D. Eisenhower was his influence in the implementation of the National Interstate and Defense Highways Act of 1956. The National Highway System serves an important role in American citizen's ground transportation. Now more than a half of a century in age, there is a high priority to repair existing infrastructure as well as the need for expansion. Repair and expansion must be achieved efficiently by reducing construction time and improving the capacity and durability of the structure. Precast, prestressed decked bulb tees (DBTs) serve as an excellent solution to ensure quality …

Design Considerations For Reinforced Concrete Masonry Walls Regarding Moment Magnification, Jarred Wade Cowart

Masters Theses

Currently, regardless of the height of a reinforced masonry wall, engineers are required to consider moment magnification when using strength design provisions. An attempt at finding reasonable h/r limits for consideration of moment magnification is explored. Moment-curvature diagrams were developed using a spreadsheet to define the behavior of 8 inch and 12 inch concrete masonry walls. A series of models were created with axial load, out-of-plane load, height, reinforcing, and wall width as variables. The models were loaded out-of-plane in a finite element program until failure. The results were organized to produce the moment magnification of each wall. Results were …