Digital Commons Network^™

Transportation Shortest Path Search Area Model, Hui Wang

Doctoral Dissertations

Although many studies on shortest-path algorithms have been conducted in the past, few of them have considered the time and effort required to obtain and update the weight property of the network arcs. For transportation-related problems – due to the size and complexity of the network – preparing, updating, and transmitting the network database on which the shortest-path algorithms perform can be a challenge.

This study designed a Transportation Shortest Path Search Area (TSPSA) model to enhance the database preparation and updating step before any shortest-path search algorithm can start processing. Taking advantage of the characteristics of the transportation networks, …

The Effects Of Temperature And Solids Retention Time On Activated Sludge Treatment Performance, Jack Mcclendon Carley

Masters Theses

A bench-scale treatment system with external clarifier was used to determine the effects of solids retention time (SRT) and temperature on treatment performance while simulating the full scale activated sludge process. Four bench-scale reactors, operating at SRTs of 20, 10, 5 and 2 days, were fed settled municipal wastewater collected after primary clarification from the Kuwahee wastewater treatment plant in Knoxville, TN. Three operational temperatures were investigated during this study, 22oC, 12oC and 7oC. The order and duration of operation at each temperature was first 22oC for 61 days, next 7oC for 47 days and lastly 12oC for 105 days. …

Comparison Of Microbial Cell Densities And Treatment Performance In Nitrifying Activated Sludge Reactors, Janalyn Rae Brown

Masters Theses

A thorough understanding of microbial dynamics in activated sludge treatment is currently unrealized due, in part, to quantitative techniques that rely on culture-dependent methods. The bias inherent with cultivation techniques may result in isolates that do not necessarily represent those dominant in the system evaluated. In situ analysis of microorganisms functioning in wastewater reactors will provide a greater understanding of how particular groups of organisms, such as nitrifiers, are impacted by system fluctuations. This information is vital for improved process design and control. The overall goal of this research was to investigate the use of the real-time polymerase chain reaction …

Assessment And Redesign Of The Synoptic Water Quality Monitoring Network In The Great Smoky Mountains National Park, Kenneth Ray Odom

Doctoral Dissertations

The purpose of this study was to assess and redesign an existing 83-site synoptic water quality monitoring network in the Great Smoky Mountains National Park. The study involved a spatial analysis of water quality data (pH, ANC, conductivity, chloride, nitrate, sulfate, sodium, and potassium), watershed characteristics (geology, morphology, and vegetation), and collocated site information to determine which sites were redundant and a temporal analysis to determine the effectiveness of the current sampling frequency to detect long-term trends. The spatial analysis employed a simulated annealing algorithm using the variable costs of the network and the results of multivariate data techniques to …

Impacts Of Environmental Factors On Flexible Pavements, Gang Zuo

Doctoral Dissertations

Mechanistic-empirical pavement design methods for flexible pavements are based on the assumption that the pavement life is inversely proportional to the magnitude of the traffic-induced pavement strains. These strains vary with the stiffness of the asphalt layer and underlying base layer and subgrade. Environmental factors, such as the temperature in the asphalt concrete layer and the water content in the base layer and the subgrade, have a significant impact on the stiffness of relevant layers in pavement systems, and consequently the estimated life of flexible pavements. A comprehensive instrumentation system was installed at four sites across the state of Tennessee …

Probabilistic Based Design Of Frp Structures, Maha Khader Alqam

Doctoral Dissertations

This thesis presents the results of an analytical probabilistic based design procedure for concentrically loaded compression members and simply supported beams of fiber-reinforced polymeric (FRP) composite materials. Resistance factors for use in an LRFD format are developed for columns for both flexural buckling and local buckling of doubly symmetric sections, both flexural buckling and flexural-torsional buckling of equal leg angles, and material failure. Resistance factors are developed for lateral-torsional buckling of simply supported doubly symmetric beams loaded with concentrated vertical loads at mid-spans. The developed resistance factors are a function of the coefficient of variation of the appropriate material properties. …

An Improved Alternative Test Method For Resilient Modulus Of Fine Grained Soils, Jonathan Michael Smolen

Masters Theses

Flexible Pavement is usually composed of several asphalt concrete layers, a granular base course and a soil subgrade. For mechanistic design of pavement systems based on elastic theory a modulus of elasticity must be designated for each design layer including the soil subgrade. The resilient modulus is used to characterize the soil in pavement design. The resilient modulus is defined as

Where s_d is the deviator stress or the difference between the axial and confining stress, and e_R is the recoverable axial strain.

The standard procedure for obtaining M_R is a repeated load tri-axial test at a …

Determination Of Mechanical Properties Of Treated Wood Using Near Infrared Spectroscopy, Stephen E. Hedrick Ii

Masters Theses

The purpose of this study was to determine the mechanical properties of treated wood using near infrared spectroscopy. This nondestructive evaluation was used to analyze the tensile strength parallel to the grain, modulus of elasticity parallel to the grain and creosote content of a southern pine telephone pole removed from service. Tests were conducted on tensile samples that were cut from sections of the pole in order to determine the actual values. Partial least squared models developed with reduced wavelengths and models developed from several 50 nanometer (nm) intervals along the spectrum showed promise in the prediction of these properties. …

1999 Improved Ammonia Emission Inventory By County In Tennessee, Yunhee Kim

Masters Theses

Ammonia gas reactions in the atmosphere are a significant source of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5um). Due to the increasing concentration of PM2.5 in the atmosphere, the need for improved ammonia emission inventories has become an increasingly important air quality issue. This study produced ammonia emission estimates for ten source categories and fifty- four sub-source categories for the State of Tennessee on a county basis for the year 1999. Livestock is a major source of total ammonia emissions in Tennessee, responsible for emitting 88,000 tons per year, with beef cows emitting 45,000 tons of ammonia …

Assessment Of Public Attitudes And Knowledge Concerning Wastewater Reuse And Biosolids Recycling, Chun Ma

Masters Theses

A telephone survey instrument was developed and administrated to evaluate public attitudes and knowledge concerning wastewater reuse and biosolids recycling with respect to population demographics (gender, age, education level, and household income). Information from 300 Knox County area residents was collected and analyzed.

The study indicated that 58% of respondents supported wastewater reuse and 75% of respondents supported biosolids recycling. Acceptance decreased with increasing possibility of contact for both wastewater reuse and biosolids recycling. For wastewater reuse, respondents were positive to applications not involving close personal contact (such as firefighting, car washing, lawn irrigation and agricultural uses), while uses of …

A Sensitivity Analysis Of The Influence Of Watershed And Development Characteristics On The Cumulative Impacts Of Stormwater Detention Ponds, Karen Marie Goff

Masters Theses

Stormwater detention ponds are a popular stormwater management practice in many communities and city ordinances often require the uniform use of detention ponds on all new developments. Stormwater detention ponds are an effective method of controlling the peak flow rate immediately downstream from a development, but a number of detention ponds scattered at random locations throughout a watershed may not effectively control peak flows throughout the watershed.

A sensitivity analysis was conducted to determine correlations between watershed and development characteristics and the response of the watershed to the uniform use of detention ponds on all developments. The cumulative impacts of …

Ozone Monitoring And Canopy Effect In The Great Smoky Mountains National Park, Ryan Maloney

Masters Theses

Vegetative uptake of ozone, or canopy effect can cause considerable differences in ozone concentration. The ability to quantify and determine the presence of canopy effect is of importance when relating ozone exposure to a health effects study being conducted in Great Smoky Mountains National Park. The concentrations seen inside and outside of the canopy differed by as much as 13 ppb and 16%. The canopy effect was quantified and evaluated to determine if the ozone concentrations measured at the trailhead at New Found Gap warranted an adjustment to accommodate for the different ozone concentrations the participants of the hiker-health study …