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Articles 571 - 600 of 654

Full-Text Articles in Civil and Environmental Engineering

P-M Characteristics Of Reinforced Concrete Sections, Paul Johnson Dec 2008

P-M Characteristics Of Reinforced Concrete Sections, Paul Johnson

All Theses

This manuscript presents two parametric studies which were performed to evaluate a provision which originated in the 1994 Uniform Building Code (UBC). This provision states that if gravity-induced axial loads carried by a reinforced concrete member are greater than 35% of the pure axial load-carrying capacity (Po) of that member, then the member cannot be used as part of the lateral force resisting system (LRFS). Along with the UBC provision, the Structural Engineers Association of California's (SEAOC) Blue Book states that the value of 0.35Po corresponds to the level of axial load representing a balanced state of strain, i.e., the …

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Analysis Of Speed-Related Crashes Using Event Data Recorder Data, Swathi Korpu Dec 2008

Analysis Of Speed-Related Crashes Using Event Data Recorder Data, Swathi Korpu

All Theses

Safety in general is defined as 'the absence of unintended harm to living creatures or inanimate objects' (Evans, 2004). Traffic safety is measured in terms of motor vehicle crashes. A crash is an unplanned event which results in either fatality, or injury or property damage. Of all the factors that contribute to a crash, speed is a major issue, as more than 31 percent of all fatal crashes involve speeding (NHTSA, 2007). The speed-safety relationship can be determined by knowing the effect of speed on the frequency and severity of crashes. The relationship between speed and frequency of crashes is …

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Experimental And Modeling Studies For Optimizing Flocculant-Aided Sediment Retention Ponds, Byung Joon Lee Dec 2008

Experimental And Modeling Studies For Optimizing Flocculant-Aided Sediment Retention Ponds, Byung Joon Lee

All Dissertations

Attempts to control sediment-containing runoff and associated water quality problems have involved the establishment of many small to medium sediment retention ponds and the injection of nonionic and anionic polyacrylamide (PAM) flocculants to enhance colloid removal. However, to date use has been driven more by practicing engineers and trial-and-error approaches than by logical and consistent design approaches. Therefore, the purpose of this research was to optimize colloidal clay removal in PAM-aided sediment retention ponds by applying experimental and theoretical methodologies.
Initially, simple measurement techniques for the molecular weight (MW) and charge density (CD) of various PAMs were tested and their …

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Optimal Maintenance Crew Composition And Enhancement Of Crew Productivity, Robert Schober Dec 2008

Optimal Maintenance Crew Composition And Enhancement Of Crew Productivity, Robert Schober

All Theses

The South Carolina Department of Transportation (SCDOT) dedicates a large portion of its budget and other resources to the maintenance of the State's transportation infrastructure. In order to maximize the efficiency and productivity of the State's highway maintenance workforce, the SCDOT partnered with Clemson University to research the performance of these maintenance crews. The goal of this research is to identify optimal crew compositions, if possible, and to suggest potential crew productivity enhancement methods.
Data was collected from the SCDOT Highway Maintenance Management System (HMMS) and crew rankings were developed based on several pre-determined performance criteria. These rankings were then …

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Effect Of Nitrification On Lead Corrosion In Chloraminated Distribution Systems, Michael Shade Sep 2008

Effect Of Nitrification On Lead Corrosion In Chloraminated Distribution Systems, Michael Shade

All Theses

Water treatment facilities have been shifting from using chlorination to chloramination as a primary disinfectant since 2004, when the EPA enacted the Disinfectants/Disinfection By-Products (D/DBP) Rule mandating the decrease of DBPs. After the switch to chloramination, an unexpected lead concentration increase was detected in the Washington, D. C., and Greenville, NC water systems. These increases may be associated with the switch from chlorination to chloramination. Decomposition of chloramines results in higher ammonia loading to drinking water distribution systems, which may increase nitrification. Nitrifying bacteria may facilitate lead corrosion via two mechanisms: use of nitrite or nitrate as an alternative electron …

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Framework For The Fully Probabilistic Analysis Of Excavation-Induced Serviceability Damage To Buildings In Soft Clays, Matt Schuster Aug 2008

Framework For The Fully Probabilistic Analysis Of Excavation-Induced Serviceability Damage To Buildings In Soft Clays, Matt Schuster

All Dissertations

In this dissertation, a framework for a fully-probabilistic analysis of the potential for building serviceability damage induced by an excavation in soft clays is established. This analysis framework is established based on the concept of a serviceability limit state where the resistance is represented by the capacity of a building to resist serviceability damage, and the loading is represented by the demand on a building due to excavation-induced ground movements. In this study, both the resistance and the loading are treated as a random variable; the resistance is characterized empirically based on a database of the observed building performance while …

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Evaluation Of Warm Asphalt Additives On Performance Properties Of Crm Binders And Mixtures, Chandra Akisetty Aug 2008

Evaluation Of Warm Asphalt Additives On Performance Properties Of Crm Binders And Mixtures, Chandra Akisetty

All Dissertations

The Warm Mix Asphalt (WMA) technologies have gained increasing popularity in recent years because of its unique property to allow the reduction in mixing and compaction temperatures of Hot Mix Asphalt (HMA) mixtures without compromising the quality of the mix. On the other hand, one of the reasons for utilizing the Crumb Rubber Modified (CRM) asphalt mixtures is that it increases the durability of the pavement by reducing the cracking and rutting potential of the pavement. However the CRM mixtures require a high mixing and compaction temperatures compared to the conventional HMA. Since the temperature requirements for CRM mixtures are …

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The Effects Of Crumb Rubber Particles On Highway Noise Reduction - A Laboratory Study, Khaldoun Shatanawi Aug 2008

The Effects Of Crumb Rubber Particles On Highway Noise Reduction - A Laboratory Study, Khaldoun Shatanawi

All Dissertations

Traffic noise is a major setback to the life quality of residents living in the vicinity of highways. Over the past 40 years, much legislation has been passed to regulate sound levels to which residents are exposed. Among the many approaches adopted to alleviate the problem, crumb rubber modified asphalt has been proposed as a measure to reduce highway traffic noise.
The use of crumb rubber modified asphalt to reduce traffic noise on pavements had not been evaluated in great detail prior to this study. This research investigates the effects of crumb rubber particles on asphalt pavement noise absorption ability. …

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Framework For Probabilistic Analysis Of Recurrent Landslides: A Case Study Of El Berrinche, Raul Flores Aug 2008

Framework For Probabilistic Analysis Of Recurrent Landslides: A Case Study Of El Berrinche, Raul Flores

All Dissertations

Assessment of slope stability or landslide is a complex geotechnical problem that involves much uncertainty. To consider combined effects of the uncertainties in soil parameters and changes in pore water pressure, reliability theory may be employed. In this dissertation study, a reliability-based framework for the probabilistic analysis of recurrent landslides is developed.
Generally, the stability of a slope is analyzed deterministically with methods of limit equilibrium and a factor of safety is computed. This approach is referred to as the deterministic approach. However, a deterministic analysis alone may not be sufficient in assessing the risk level of a landslide in …

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A Real-Time Traffic Condition Assessment And Prediction Framework Using Vehicle-Infrastructure Integration (Vii) With Computational Intelligence, Yongchang Ma Aug 2008

A Real-Time Traffic Condition Assessment And Prediction Framework Using Vehicle-Infrastructure Integration (Vii) With Computational Intelligence, Yongchang Ma

All Dissertations

This research developed a real-time traffic condition assessment and prediction framework using Vehicle-Infrastructure Integration (VII) with computational intelligence to improve the existing traffic surveillance system. Due to the prohibited expenses and complexity involved for the field experiment of such a system, this study adopted state-of-the-art simulation tools as an efficient alternative.
This work developed an integrated traffic and communication simulation platform to facilitate the design and evaluation of a wide range of online traffic surveillance and management system in both traffic and communication domain. Using the integrated simulator, the author evaluated the performance of different combination of communication medium and …

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Crumb Rubber As A Sorption Medium For Ethylbenzene In Aqueous Solution, Carmen Grayson Aug 2008

Crumb Rubber As A Sorption Medium For Ethylbenzene In Aqueous Solution, Carmen Grayson

All Theses

Scrap tires have always been an environmental concern. In 2005, more than 299 million scrap tires were generated in the U.S., 259 million of which were utilized in the end-use scrap tire markets such as: tire-derived fuel generation, civil engineering applications, and ground rubber applications. The different applications and usages in the scrap tire market have helped utilize up to 87% of annually generated scrap tires in the U.S. Sixteen percent of the scrap tires were utilized in civil engineering applications in 2005 because of their beneficial properties for vibration and sound control, lightweight fill, drainage and collection for underground …

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Spatial Variability Of Radionuclide Distribution Coefficients At The Savannah River Site And The Sub-Surface Transport Implications, Kelly Grogan Aug 2008

Spatial Variability Of Radionuclide Distribution Coefficients At The Savannah River Site And The Sub-Surface Transport Implications, Kelly Grogan

All Theses

Distribution coefficients, Kd, were measured for a suite of gamma-emitting radionuclides in uncontaminated soils from the E-Area burial grounds at the Savannah River Site. The objectives of the study were to (1) characterize the spatial variability of Kd, (2) evaluate the effect of spatial variability on vadose zone transport, and (3) develop statistical models for predicting Kd from physical or chemical characteristics.
Equilibrium batch sorption tests were performed on 27 soil samples collected from depths ranging from 11 ft to 100 ft from the BGO-3A core with 241Am, 109Cd, 139Ce, 137Cs, 57Co, 60Co, 203Hg, 85Sr, and 88Y. Distribution coefficients were …

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Exploration Of A Carbon Nanotube Anode Gas-Filled Radiation Detector, Landon Pruitt Aug 2008

Exploration Of A Carbon Nanotube Anode Gas-Filled Radiation Detector, Landon Pruitt

All Theses

The primary objective of this study was to design, test, and model the electrostatic field in a gas-filled radiation detector constructed with either a carbon nanotube (CNT) or a CNT array as the anode. Tungsten anodes of 500 to 4μm diameters were used to observe the gradual decrease in operating voltage with a decreasing anode diameter and estimate efficiencies of CNT anodes in a coaxial design. An electrostatic model (Maxwell 3D/2D) was used to model the resulting electric field associated with a single CNT in the coaxial configuration as well as to optimize the pitch (distance between individual CNTs in …

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Effect Of Testing Conditions In The Standard Astm C 1567 Test Procedure On Evaluation Of Asr Mitigation Potential Of Fly Ashes, Pavan Seemakurty Aug 2008

Effect Of Testing Conditions In The Standard Astm C 1567 Test Procedure On Evaluation Of Asr Mitigation Potential Of Fly Ashes, Pavan Seemakurty

All Theses

Alkali Silica Reaction (ASR) is a widespread durability problem not only in the United States, but also in many countries across the world. ASR distress in concrete drastically reduces the service life of a structure and as such, there are no effective rehabilitation measures. As a result, the primary strategy to deal with ASR distress has been one of prevention/mitigation in new construction. Various mitigation measures are widely used to reduce the effects of ASR in concrete. Among these measures, the use of supplementary cementing materials (SCMs) is the most commonly employed method. SCMs are believed to mitigate expansions induced …

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Laboratory Evaluation Of Polycyclic Aromatic Hydrocarbon Biodegradation At A Former Tar Plant Site, Mihika Baruah Aug 2008

Laboratory Evaluation Of Polycyclic Aromatic Hydrocarbon Biodegradation At A Former Tar Plant Site, Mihika Baruah

All Theses

A former tar plant site in the southeastern
U.S. is one of hundreds across the country that is contaminated with polycyclic
aromatic hydrocarbons (PAHs). The 2007
CERCLA Priority List of Hazardous Substances ranks PAHs as the eighth most
prominent hazardous substance at National Priority List sites. However, benzo(a)pyrene
is the only PAH that is regulated under the Safe Drinking Water Act, with a maximum
contaminant level of 0.2 µg/l. As with most sites, monitored natural
attenuation was the preferred bioremediation approach for this site, assuming
it could be shown that the PAHs were undergoing biodegradation. Field data from the site …

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Assessment Of Potential Site Selection Methods For Use In Prioritizing Safety Improvements On Georgia Roadways, Priyanka Alluri Jul 2008

Assessment Of Potential Site Selection Methods For Use In Prioritizing Safety Improvements On Georgia Roadways, Priyanka Alluri

All Theses

With over 40,000 people continuing to die on US roads each year, the US government has heightened the awareness of critical safety issues with the passage of SAFETEA - LU legislation in 2005. The plan requires each of the states to develop a Strategic Highway Safety Plan (SHSP) and incorporate data-driven approaches to prioritize and evaluate program outcomes; else federal funds will be redirected. Seeking to meet the new demands for data-driven approaches, many states are struggling to identify data collection/maintenance requirements for satisfying new approaches to highway safety analysis. Recent research has shown that selecting projects on the basis …

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Scale-Up And Characterization Of An Enrichment Culture For Bioaugmentation Of The P-Area Chlorinated Ethene Plume At The Savannah River Site, Ashley Eaddy Jul 2008

Scale-Up And Characterization Of An Enrichment Culture For Bioaugmentation Of The P-Area Chlorinated Ethene Plume At The Savannah River Site, Ashley Eaddy

All Theses

Bioaugmentation has become an increasingly popular remediation strategy for groundwater sites contaminated with chlorinated solvents. When biostimulation is not an option due to the lack of necessary microorganisms required for dechlorination of the contaminants, bioaugmentation is an attractive option for remediation. The P-Area groundwater plumes at the Savannah River Site (SRS) are just such a case. The P-Area site is contaminated with tetrachloroethene (PCE), trichloroethene (TCE), and cis-dichloroethene (cDCE), and no dechlorination past cDCE is occurring. A similar site, the C-Area site, is near one of the P-Area site's source zones but displays complete reduction of TCE to ethene. …

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Estimating In-Situ Flexural Strength Of Heat-Affected Prestressed Concrete Beams Using Constituent Material Models, Travis Collins Jul 2008

Estimating In-Situ Flexural Strength Of Heat-Affected Prestressed Concrete Beams Using Constituent Material Models, Travis Collins

All Theses

When a prestressed concrete structure is subjected to a severe fire, significant damage is created to the extent that a visual analysis is sufficient in rendering the structure unusable. Although moderate fires also create structural damage, the effects can often not be visually assessed. Therefore, a need exists for a method that allows structures to be evaluated after a fire has occurred and visual observations present no conclusive evidence for making decisions regarding the structural impact of the fire on the structure.
It was assumed that temperature histories of a member arising from a moderate fire can be determined using …

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Microcosm Evaluation Of Vinyl Chloride Bio-Oxidation Under Anaerobic Conditions, Jessica High Jul 2008

Microcosm Evaluation Of Vinyl Chloride Bio-Oxidation Under Anaerobic Conditions, Jessica High

All Theses

The vast majority of hazardous waste sites in the US have groundwater contaminated with halogenated organic solvents, primarily tetrachloroethene (PCE) and trichloroethene (TCE). Because the cost to remediate these sites is projected to exceed hundreds of billions of dollars, there is considerable interest in utilizing bioremediation as a low-cost remedy. Under anaerobic conditions, the best characterized biodegradation pathway for chlorinated ethenes is reductive dechlorination, whereby an electron donor such as hydrogen provides the reducing equivalents needed to replace chlorine atoms with hydrogen atoms. The ultimate daughter products from chlorinated ethenes are non-hazardous ethene and ethane, a process easily documented with …

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Fecal Coliform Source Identification Using Chemical Tracers, Nicole Fahrenfeld Jul 2008

Fecal Coliform Source Identification Using Chemical Tracers, Nicole Fahrenfeld

All Theses

Fecal sterols and fluorinated whitening agents (FWA) were used as chemical tracers for fecal coliform source tracking in Cane and Little Cane creeks in Walhalla, SC. Fecal sterols were quantifiable in both stream sediments and suspended particulates using an extraction, clean-up, and analytical method modified from Isobe et al. (2002) with a N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization scheme. Only human sterol source identification ratios were able to be calculated using the chosen sterol suite. Human fecal signatures were seen in both the sediment and the water column at various points along both creeks, indicating human fecal pollution is contributing to the fecal …

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Investigation Of The Discharge Coefficient For Circular Orifices In Riser Pipes, David Prohaska Jul 2008

Investigation Of The Discharge Coefficient For Circular Orifices In Riser Pipes, David Prohaska

All Theses

The purpose of this study is to examine the discharge coefficient as it pertains to
flow through a circular orifice cut into a thin-walled vertical riser pipe. Perforated riser
pipes are a popular outlet control structure for stormwater detention basins. These
basins are used to store and release stormwater runoff from impervious areas of
developed sites. Federal, state, and local regulatory agencies provide requirements for
the quality of stormwater runoff, as well as the maximum peak discharges from a
developed site. Accurately determining the flow rate from a perforated vertical riser
pipe is crucial to meeting these requirements and protecting …

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Investigation Of The Effects Of Aggregate Properties And Gradation On Pervious Concrete Mixtures, Andrew Neptune Jul 2008

Investigation Of The Effects Of Aggregate Properties And Gradation On Pervious Concrete Mixtures, Andrew Neptune

All Theses

Pervious concrete is a concrete mixture prepared from cement, aggregates, water, little or no fines and in some cases admixtures. It has been considered a Best Management Practice by the EPA because of its ability to reduce storm water runoff and to initiate the filtering of pollutants. Because the hydrologic properties of pervious concrete has been the primary reason for its reappearance in construction, the focus of previous research has been on maximizing the drainage properties of the mix with single-sized aggregates. This research, however, investigates the effects of aggregate properties and gradation on the strength, as well as hydrologic …

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A Laboratory Study On The Effects Of Submerged Vertical And Semicircular Breakwaters On Near-Field Hydrodynamics And Morphodynamics, David Young May 2008

A Laboratory Study On The Effects Of Submerged Vertical And Semicircular Breakwaters On Near-Field Hydrodynamics And Morphodynamics, David Young

All Theses

A laboratory study is presented herein that investigates the effects of submerged vertical and semicircular breakwaters on near-field hydrodynamics and morphodynamics. Breakwaters are employed worldwide in order to reduce destructive wave forces often imparted on vulnerable shorelines; a task partially completed by reflecting incident wave energy back out to sea. However, two common side-effects of their function are the occurrence of scour at the breakwater, which can lead to structural problems; and offshore ripple formations, which are influential in scour protection failure and sediment transport patterns. This study aims to determine a relationship between breakwaters and the wave reflection coefficient …

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Development Of A Colorimetric Test For Quantification Of Uranium In Drinking Water, Amy Ratliff May 2008

Development Of A Colorimetric Test For Quantification Of Uranium In Drinking Water, Amy Ratliff

All Theses

A new method was developed for the determination of uranium in groundwater above 30µg/L (30ppb). This concentration is the maximum contaminant level (MCL) for uranium in drinking water, which was set in December 2003 by the US EPA under the provisions of the Safe Drinking Water Act. The method is rapid and requires little technical training to conduct, allowing it to be used by consumers, in the laboratory, or in the field. The two-step technique involves preconcentrating uranium using a U/TEVA-2 extraction chromatographic resin followed by complexation with a pyridylazo indicator dye, Br-PADAP. At neutral pH, a counter ion is …

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Geotechnical Investigations At Three Sites In The South Carolina Coastal Plain That Did Not Liquefy During The 1886 Charleston Earthquake, Ronald Boller May 2008

Geotechnical Investigations At Three Sites In The South Carolina Coastal Plain That Did Not Liquefy During The 1886 Charleston Earthquake, Ronald Boller

All Theses

Geotechnical investigations were performed at three sites in the South Carolina Coastal Plain where liquefaction is believed to not have occurred in 1886 or during other Holocene earthquakes. The three sites are the Coastal Research and Education Center (CREC) located near Charleston, and the Borrow Pit and Marsh Road sites at Hobcaw Barony near Georgetown. The investigations consisted of nine seismic cone penetration test (SCPT) soundings, three non-seismic cone penetration test (CPT) soundings, one standard penetration test (SPT) boring, and two dilatometer test (DMT) soundings. Shear wave velocities (Vs) were calculated from the SCPTs using pseudo interval measurements at the …

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Hypoelastic Modeling Of Reinforced Concrete Walls, Mohsen A. Shayanfar, Amir Safiey May 2008

Hypoelastic Modeling Of Reinforced Concrete Walls, Mohsen A. Shayanfar, Amir Safiey

Publications

This paper presents a new hypoelasticity model which was implemented in a nonlinear finite element formulation to analyze reinforced concrete (RC) structures. The model includes a new hypoelasticity constitutive relationship utilizing the rotation of material axis through successive iterations. The model can account for high nonlinearity of the stress-strain behavior of the concrete in the pre-peak regime, the softening behavior of the concrete in the post-peak regime and the irrecoverable volume dilatation at high levels of compressive load. This research introduces the modified version of the common application orthotropic stress-strain relation developed by Darwin and Pecknold. It is endeavored not …

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Storm Water Export Of Nitrogen, Phosphorous, And Carbon From Developing Catchments In The Upper Piedmont Physiographic Province, Laura Reid May 2008

Storm Water Export Of Nitrogen, Phosphorous, And Carbon From Developing Catchments In The Upper Piedmont Physiographic Province, Laura Reid

All Theses

Impacts on water quality caused by land use change from forests and pastures to housing subdivisions were evaluated in catchments undergoing active development in the upper Piedmont physiographic province of South Carolina. Specific attention was focused on the export of nitrogen, phosphorus and carbon from these catchments during storm events. Three catchments with varying stages of development were compared to categorize the effects of land disturbance. Storm events occurring within a four year period of 2004 through 2007 were studied for changes in water quality within catchment streams. Due to the potential large input of surface runoff to streams following …

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Analysis Of The Impact Of Fuel Price And Bidding Volume On The Engineer's Estimate, Greaton Sellers May 2008

Analysis Of The Impact Of Fuel Price And Bidding Volume On The Engineer's Estimate, Greaton Sellers

All Theses

The research project 'Analysis of the Impact of Fuel Price and Bidding Volume on the Engineer's Estimate' was initiated by the South Carolina Department of Transportation and conducted by Clemson University. This research was executed as a two part study, 'Best Practices for Developing the Engineer's Estimate', which addressed two distinct but related objectives. The first research objective was to fully explore the advantages and disadvantage of alternative methodologies utilized to compile the engineer's cost estimate. This research objective is addressed in Report Volume I. The second research objective, which is addressed in this Report Volume II, was to develop …

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Anaerobic Biodegradation Of Ethylene Dibromide And 1,2-Dichloroethane In The Presence Of Fuel Hydrocarbons, James Henderson May 2008

Anaerobic Biodegradation Of Ethylene Dibromide And 1,2-Dichloroethane In The Presence Of Fuel Hydrocarbons, James Henderson

All Dissertations

Field evidence from underground storage tank (UST) sites where leaded gasoline leaked indicates the lead scavengers 1,2-dibromoethane (ethylene dibromide, or EDB) and 1,2-dichloroethane (1,2-DCA) may be present in groundwater at levels that pose unacceptable risk. These compounds are seldom tested for at UST sites. Although dehalogenation of EDB and 1,2-DCA is known to occur, the effect of fuel hydrocarbons on their biodegradability under anaerobic conditions is poorly understood. Microcosms (2 L glass bottles) were prepared with soil and groundwater from a UST site in Clemson, South Carolina, using samples collected from the source (containing residual fuel) and less contaminated downgradient …

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The Formation Of Halonitromethanes In Wastewater Treatment Plant Effluents, Jesse Addison May 2008

The Formation Of Halonitromethanes In Wastewater Treatment Plant Effluents, Jesse Addison

All Theses

Disinfection by-products (DBPs) have been a water treatment concern since their discovery in the 1970's. Today, only eleven drinking water DBPs are regulated by the Environmental Protection Agency (EPA). However, over 500 DBPs have been identified in drinking waters with advances in analytical methods within the last two decades. Halonitromethanes (HNMs) were among the fifty-plus unregulated high-priority DBPs that were monitored for and detected in drinking waters in a recent nationwide occurrence study funded by EPA. The toxicology studies conducted in recent years showed that HNMs are one of the most cytotoxic and genotoxic classes among the emerging DBPs, and …

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