Engineering Commons^™

Correlating Suspended Sediment And Biological Metrics In East Tennessee Streams, Jeremy Robert Mefford

Masters Theses

Excessive suspended sediment is a major cause of pollution in US streams, as reported by the USEPA. Also known as siltation, having excessive sediment in a stream harms the biology of a stream through directly affecting living organisms, but also through harming natural habitats. Too much excessive sediment leads to a stream being declared impaired. Testing for suspended sediment levels is difficult and time consuming, so indirect methods of testing for total suspended solids (TSS) are desirable. While turbidity has been an oft used TSS surrogate in the past, this study takes the next step of looking at potential relationships …

Potential Impacts Of Climate Change On Water Resources And Water Quality Of Norris Lake, Tennessee, Yong-Gil Choi

Masters Theses

This study assessed the potential impacts of climate change on hydrology, water resources operation, and water quality of the Norris Lake area in Tennessee. To project future climate conditions, the simulation outputs for 2030s, 2050s, and 2070s from six general circulation models (GCMs) were extracted under two Intergovernmental Panel on Climate Change (IPCC) greenhouse gases emissions scenarios (A2 and B1 for high and low emissions, respectively) to consider the range of uncertainty. The outputs of the six GCMs were weighted by considering their accuracy to simulate the climate conditions observed from 1961 to 1990 to suggest an ensemble average. A …

Performance Specification For Tennessee Bridge Decks, Brian Ray Buchanan

Masters Theses

In today’s world of ever increasing demand on a weakening infrastructure, concentration is being firmly placed on increasing the sustainability of that infrastructure. Tennessee’s bridges and the concrete decks, on which the public travels, require a large part of the state’s infrastructure spending. Research has shown the current durability standards of Tennessee’s bridge decks could be significantly improved which would both increase service life and reduce maintenance costs of these structures. This research concentrates on greatly increasing the lifespan of these bridge decks, throughout the state, through an improved construction specification which will encourage the increased use of supplementary cementitious …

Behavior Of Externally Fiber-Reinforced Polymer Reinforced Shrinkage-Compensating Concrete Beams, Qi Cao

Doctoral Dissertations

The major cause of cracking in bridge decks, concrete pavements, as well as slabs on grade, is restrained shrinkage of the concrete. The resulting steel corrosion problem causes tremendous increase of maintenance and replacement cost. Shrinkage-compensating concrete (SHCC) and fiber-reinforced polymer (FRP) are explored to develop a hybrid slab system as one possible method of delaying the cracking and eliminating corrosion. To achieve the objective, a hybrid FRP reinforced SHCC structural system was developmed, and short-term and long-term behavior of this hybrid FRP-SHCC beams were investigated in this dissertation.

In the first-stage development, a series of “coffee can” tests were …

Characterization And Modeling Of Toxic Fly Ash Constituents In The Environment, Zhenwei Zhu

Doctoral Dissertations

Coal fly ash is a by-product of coal combustion that has drawn renewed public scrutiny due to the negative environmental impacts from accidental release of this waste material from storage facilities. Historically, the leaching of toxic elements from coal fly ash into the environment has always been a major environmental concern. Despite extensive efforts into the characterization of coal fly ash, effective models for the fate and transport of toxic fly ash constituents have remained lacking, making it difficult to perform accurate environmental impact assessment for coal fly ash. To close this critical knowledge gap, the overall objective of this …

Oceanic-Atmospheric And Hydrologic Variability In Long Lead-Time Forecasting, Abdoul Aziz Oubeidillah

Doctoral Dissertations

Water managers throughout the world are challenged with managing scarce resources and therefore rely heavily on forecasts to allocate and meet various water demands. The need for improved streamflow and snowpack forecast models is of the utmost importance. In this research, the use of oceanic and atmospheric variables as predictors was investigated to improve the long lead-time (three to nine months) forecast of streamflow and snowpack. Singular Value Decomposition (SVD) analysis was used to identify a region of Pacific and Atlantic Ocean SSTs and a region of 500 mbar geopotential height (Z500mb) that were teleconnected with streamflow and snowpack. The …

A Life Cycle Comparison Of Light-Frame Wood And Insulated Concrete Form Building Envelopes: Energy Use And Green House Gases, Sherman Authur Matthews

Masters Theses

Given the building sector’s substantial contribution to global energy use and green house gas (GHG) emissions, it is of great importance that only the most effective building envelopes are utilized. Conventional light-frame wood building envelopes are highly popular due to their ease of construction and building economy; however the life cycle performance of the building envelope is often overlooked when this selection is made. Although insulated concrete form (ICF) building envelopes generally require a substantially higher embodied energy input, it should be considered that improvements during a building’s operation phase can offers significant energy returns, ultimately reducing the building’s life …

The Effects Of Varying Physical Parameterizations And Initial Conditions On Tracer Transport In The National Aeronautics And Space Administration’S Goddard Earth Observation System Model, Version 5, Melissa Ree Allen

Masters Theses

The evolution of General Circulation Models (GCM) for climate study has led to more accurate predictions for atmospheric transport, yet precision in predictions remains in need of improvement. The National Aeronautics and Space Administration Goddard Earth Observation System model, Version 5 (GEOS-5) represents a state of the art climate model capable of simulating a wide variety of atmospheric processes informed continuously by satellite observations. This thesis examines some of the physical parameterizations employed by GEOS-5 and their effect on the transport of two greenhouse gasses: ozone and carbon dioxide.

Bankfull Geomorphic Relationships And Reference Reach Assessment Of The Ridge And Valley Physiographic Province Of East Tennessee, James Brady Mcpherson

Masters Theses

Waterways have been geomorphically altered or disturbed by development, mining, agriculture and other human activities for many years. Section 404 of the Clean Water Act determined that these impacts to our waterways must be mitigated for channel alterations. Stream restoration has been one method to mitigate for these impacts to our water resources. Stream restoration is considered to be a measurable improvement to the channel stability, water quality, habitat or overall function of a degraded stream system. Practices of stream restoration have changed in the last 10 to 20 years with the introduction of natural channel design methods. Natural channel …

Comparison Of Two Methods For The Assessment Of Chloride Ion Penetration In Concrete: A Field Study, Eric William Ryan

Masters Theses

The currently accepted method for assessing the resistance of concrete to penetration of chloride ions is ASTM C1202, commonly known as the “Rapid Chloride Permeability (RCP) Test.” The test is time-consuming, laborious, has rather high variability, and, is to a degree, user sensitive, making it problematic for inclusion in a performance-based specification. A potential alternative to the RCP test is the “Surface Resistivity (SR) Test”, a method which is dramatically easier, faster, and has less variability than the RCP test. The research reported herein was directed toward determining a correlation between RCP and SR test measurements for Tennessee bridge deck …

Discrete Element Method (Dem) Analyses For Hot-Mix Asphalt (Hma) Mixture Compaction, Jingsong Chen

Doctoral Dissertations

Asphalt mixture compaction is an important procedure of asphalt mixture construction and can significantly affect the performance of asphalt pavement. Many laboratory compaction methods (or devices), have been developed to study the asphalt mixture compaction. Nevertheless, the whole process from the selection of aggregate to laboratory compaction is still time-consuming and requires significant human and material resources. In order to better understand asphalt mixture compaction, some researchers began to use finite element method (FEM) to study and analyze mixture compaction. However, FEM is a continuum approach and lacks the ability to take into account the slippage and interlocking of aggregates …

Enhancement Of Pavement Maintenance Decision Making By Evaluating The Effectiveness Of Pavement Maintenance Treatments, Qiao Dong

Doctoral Dissertations

The performance of different pavement maintenance treatments were evaluated by investigating practical projects collected from Tennessee Pavement Management System (PMS) and Long Term Pavement Performance (LTPP) database. The influence of factors on the effectiveness, cost-effectiveness and cracking initiation of different treatment were evaluated by “Optime”, multiple linear regression and parametric survival analysis. Pavement roughness, pavement serviceability index (PSI) and the initiation time of cracking were used as pavement performance indicators.

Investigation on the pavement maintenance projects in Tennessee by Optime and multiple linear regression analysis indicated that HMA overlay had the highest effectiveness, followed by mill & fill and micro …

Investigating Properties Of Pavement Materials Utilizing Loaded Wheel Tester (Lwt), Hao Wu

Doctoral Dissertations

Loaded wheel tester (LWT) is a common testing equipment usually used to test the permanent deformation and moisture susceptibility of asphalt mixtures by applying moving wheel loads on asphalt mixture specimens. It has been widely used in the United States since 1980s and practically each Department of Transportation or highway agency owns one or more LWT(s). Compared to other testing methods for pavement materials, LWT features movable wheel loads that allow more realistic situations existing on the actual pavement to be simulated in the laboratory. Due to its potential of creating a condition of repetitive loading, the concept of using …

Impacts Of Future Climate Change And Effects Of Biogenic Emissions On Surface Ozone And Particulate Matter Concentrations In The United States, Y. F. Lam, Joshua Fu, S. Wu, L. J. Mickley

Faculty Publications and Other Works -- Civil & Environmental Engineering

Simulations of present and future average regional ozone and PM_2.5 concentrations over the United States were performed to investigate the potential impacts of global climate change and emissions on regional air quality using CMAQ. Various emissions and climate conditions with different biogenic emissions and domain resolutions were implemented to study the sensitivity of future air quality trends from the impacts of changing biogenic emissions. A comparison of GEOS-Chem and CMAQ was performed to investigate the effect of downscaling on the prediction of future air quality trends. For ozone, the impacts of global climate change are relatively smaller when compared …

Sustainability Analysis Of Personal Transportation For Near Urban Commuting, Michelle Everett, Michael Pickelsimer, Virginia Browning, William R. Henson, James R. Hall Jr., Yue Cao, Justin Ridenour, Theodore Ansink, James Wilson, Eugene Ng, Matthew Atchley, Scott Teeters, David Irick, Leon Tolbert, Chris Cherry, Robert Counce, Paul D. Frymier

Faculty Publications and Other Works -- Mechanical, Aerospace and Biomedical Engineering

The goal of this P3 project was to test three hypotheses: 1) there exists a vehicle or class of vehicles that can be effectively used to replace a car for near-urban commuting and short range transportation in cities of similar population, topology and traffic volume as Knoxville, TN with significantly less environmental impact than a typical automobile, 2) this vehicle has the appropriate capacity, convenience, and comfort such that people who are not likely to use other forms of alternate transportation will adopt it, and 3) between a fuel cell hybrid and fully battery electric, one of the two designs …

North Platte Snowpack Reconstructions Using Dendrochronology, Amanda Kate Bowen

Masters Theses

April 1^st Snow Water Equivalent (SWE) reconstructions were generated using tree-ring chronologies for the Upper North Platte River Basin (UNPRB), located in north-central Colorado and south-eastern Wyoming. To regionalize April 1^st snowpack data from 11 SNOw TELemetry stations (SNOTEL stations), Varimax Rotated Principal Components Analysis (PCA) was used. For the 11 station regionalization, the reconstruction explained 42% of the variance in the instrumental record and extended the record to 1378 (632 years). Retained tree-ring chronologies included those that were stable and positively correlated at 99% confidence levels or higher with the regional snowpack data for a 60–year overlapping …

Comparison Of Baseflow-Stormflow Ion Mass Export For Two Streams In The Great Smoky Mountains National Park, Guy Thomas Zimmerman

Masters Theses

This study characterizes the mass transport of ions in two streams in the Great Smoky Mountains National Park, comparing transport between stormflow and baseflow periods. By comparing ion mass transport between these two hydrological conditions, the importance of soil and the governing biogeochemical processes will be underscored. Two water quality monitoring study sites were located on the Middle Prong of the Little Pigeon River and Ramsey Prong within the same basin. These remote sites were equipped with YSI 6920 multi-parameter sonde to record continuous 15-min data of pH, depth, conductivity, turbidity, and temperature. Additionally, ISCO 6712 composite samplers were used …

Development Of Design Guidelines For Cip Joint Connections With U-Bar Reinforcement, Richard Aaron Hanks

Masters Theses

The interstate highway system is vitally dependent upon current and future bridges. These bridges must be designed economically to continue the serviceability with limited maintenance. For precast bridge construction a portion of the design must consider the bridge connections. Some current connections have proved insufficient in serviceability as there is uncontrolled cracking. In other connections there are uncertainties in the calculations (or lack of calculations) which require design guidelines.

This thesis presents design recommendations for precast decking u-bar reinforcement in tension which results from negative moment over a pier. Testing results from the University of Tennessee were analyzed to determine …

Air Quality And Emissions In The Yangtze River Delta, China, L. Li, C. H. Chen, Joshua Fu, C. Huang, D. G. Streets, H. Y. Huang, G. F. Zhang, Y. J. Wang, C. J. Jang, H. L. Wang, Y. R. Chen, J. M. Fu

Faculty Publications and Other Works -- Civil & Environmental Engineering

Regional trans-boundary air pollution has become an important issue in the field of air pollution modeling. This paper presents the results of the implementation of the MM5-CMAQ modeling system in the Yangtze River Delta (YRD) for the months of January and July of 2004. The meteorological parameters are obtained by using the MM5 model. A new regional emission inventory with spatial and temporal allocations based on local statistical data has been developed to provide input emissions data to the MM5-CMAQ modeling system. The pollutant concentrations obtained from the MM5-CMAQ modeling system have been compared with observational data from the national …

Characteristics, Sources And Formation Of Aerosol Oxalate In An Eastern Asia Megacity And Its Implication To Haze Pollution, Y Jiang, G Zhuang, Q Wang, T Liu, K Huang, Joshua S. Fu, J Li, Y Lin, R Zhang, C Deng

Faculty Publications and Other Works -- Civil & Environmental Engineering

A total of 238 samples of PM_2.5 and TSP were analyzed to study the characteristics, sources, and formation pathways of aerosol oxalate in Shanghai in four seasons of 2007. The concentrations of oxalate were 0.07–0.41 μg m⁻³ in PM_2.5 and 0.10–0.48 μg m⁻³ in TSP, respectively. Oxalate displayed a seasonal variation of autumn>summer>winter>spring in both PM_2.5 and TSP and was dominantly present in PM_2.5 in all samples. Correlation between oxalate and K⁺ and high ratio of oxalate/K⁺ suggested that biomass burning was a secondary source of aerosol oxalate in …

A Regional Chemical Transport Modeling To Identify The Influences Of Biomass Burning During 2006 Base-Asia, Joshua Fu, N C. Hsu, Y Gao, K Huang, C Li, N H. Lin, S C. Tsay

Faculty Publications and Other Works -- Civil & Environmental Engineering

To evaluate the impact of biomass burning from Southeast Asia to East Asia, this study conducted numerical simulations during NASA's 2006 Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment (BASE-ASIA). Two typical episode periods (27–28 March and 13–14 April) were examined. Two emission inventories, FLAMBE and GFED, were used in the simulations. The influences during two episodes in the source region (Southeast Asia) contributed to CO, O₃ and PM_2.5 concentrations as high as 400 ppbv, 20 ppbv and 80 μg/m³, respectively. The perturbations with and without biomass burning of the above three species were in the …

A Regional Chemical Transport Modeling To Identify The Influences Of Biomass Burning During 2006 Base-Asia, Joshua Fu, N. C. Hsu, Y. Gao, K. Huang, C. Li, N.-H. Lin, S.-C. Tsay

Faculty Publications and Other Works -- Civil & Environmental Engineering

To evaluate the impact of biomass burning from Southeast Asia to East Asia, this study conducted numerical simulations during NASA's 2006 Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment (BASE-ASIA). Two typical episode periods (27–28 March and 13–14 April) were examined. Two emission inventories, FLAMBE and GFED, were used in the simulations. The influences during two episodes in the source region (Southeast Asia) contributed to CO, O₃ and PM_2.5 concentrations as high as 400 ppbv, 20 ppbv and 80 μg/m³, respectively. The perturbations with and without biomass burning of the above three species were in the …