Engineering Commons^™

Corrosion Studies On Alpha Tantalum And Beta Tantalum Coated Steel, Sung Min Maeng

Dissertations

Tantalum coating by sputtering, one form of physical vapor deposition (PVD), has been investigated as a replacement for chromium coatings on gun bores to protect them from erosion and corrosion due to its high ductility and high corrosion resistance in aggressive environments. When deposited as a film on steel substrates by sputtering, either α-Ta, β-Ta, or a mixture of both phases have been observed under varying deposition conditions. To evaluate corrosion behavior of Ta coatings, electrochemical impedance spectroscopy and potentiodynamic polarization were conducted as a function of coating thickness. The coating porosity was observed to decrease with increasing coating thickness …

Development And Application Of Fractionation Procedure For Drinking Water Organic Matters, Yong Pu

Dissertations

USEPA mandates a control of disinfection by-products (DBPs) in finished drinking water and recommends reduction of natural organic matters (NOM), DBP precursors, to achieve this regulatory goal. Studies relating NOM with DBP include fractionation of water samples, characterization of collected organic fractions, fractions' formation potential tests, and jar or similar tests to remove NOM. This study discussed a current resin fractionation procedure on principle, procedure, and its efficiency when applied to water samples of low NOM (< 5mgIL). The primary objective of this research is to develop a fractionation procedure intended for water of low NOM by carefully applying mass balance concept through each fraction's fractionation and a selection of stable ion exchange resins. A new protocol was presented with triple columns of XAD-8 adsorption resin, one column of AG-MP-50 cationic resin, and another column of WA 10 weak anionic resin in sequence. This protocol was experimented and confirmed for its efficiency (±10% loss of mass) with samples from Canal Road (CR) and Raritan Millstone (RM) surface water treatment plants (WTPs) in central New Jersey. The second objective of this study is to develop a statistical model with a potential of online delineation of organic fractions of NOM. The resulting model based on samples of Passaic Valley Water Commission (PVWC) WTP in northern New Jersey was applied to predict organic fractions of samples from CR and RM plants. Paired T-test (paired t ratio 1.15 < t critical 2.02) indicated a good correlation between the predicted and actual fraction concentration. Finally, samples of Middlesex Water Company (MWC) were fractionated and Trihalomethane formation potential tests (THMFP) on collected fraction showed hydrophilic matters possessed a higher potential to produce TTHM in finished water than hydrophobic matter. Jar tests indicated while coagulation was effective in removing hydrophobic matter, it may not be optimum for removal of hydrophilic matter.

This study developed an accurate fractionation procedure for low NOM waters. It provided a better understanding of organic matter transformation at different treatment …

Tide-Influenced Contaminant Transport In Coastal Aquifers, Yong Peng

Dissertations

Coastal aquifers are distinguished from other aquifers because of tidal effects which cause complicated groundwater flow and contaminant transport phenomena in regions immediately adjacent to the coast. This study is designed to address the significance of tidal influence on contaminant transport by focusing on one-dimensional homogeneous coastal aquifers.

This study formulates a conceptual model and corresponding flow and transport equations, analyzes coastal boundary conditions, solves numerically the transport equation, and uses experiments to verify the numerical results.

Results of numerical and experimental studies conclude that tides can have a significant impact on contaminant transport, especially when under unconfined conditions, subject …

Modeling Contaminant Transport And Fate And Subsequent Impacts On Ecosystems, Ming Fan

Dissertations

Assessing risks associated with the release of metals into the environment and managing remedial activities requires simulation tools that depict speciation and risk with accurate mechanistic models and well-defined transport parameters. Such tools need to address the following processes: (1) aqueous speciation, (2) distribution mechanisms, (3) transport, and (4) ecological risk. The primary objective of this research is to develop a simulation tool that accounts for these processes. Speciation in the aqueous phase can be assessed with geochemical equilibrium models, such as MINEQL+. Furthermore, metal distribution can be addressed mechanistically. Studies with Pb sorption to amorphous aluminum (HAG), iron (HFO), …

The Use Of A Water Quality Model To Evaluate The Impacts Of Combined Sewer Overflows On The Lower Hudson River, Wen-Pin Shu

Dissertations

CSO discharges have long been recognized as a significant source of water pollution. While many sources of water pollution have been controlled over the past 20 years, CSOs continue to be a main environmental concern in several areas, especially in old cities. In the past, most CSO research focused on the CSO control processes, including floatables and suspended solids removal. Few studies have been conducted in the area of the impacts of CSO discharge on the receiving water quality. To achieve this purpose, a powerful water-modeling tool, WASP 6.1, is utilized in this study. The Lower Hudson River is selected …

Remediation Of Chromium Contaminated Soils With Colloidal Silica, Netnapid Yossapol

Dissertations

The low-viscosity stabilizer, colloidal silica, is extensively used as a grouting material in the construction of grout curtains. It has low viscosity and is non-toxic, which is suitable for injection to stabilize fine-grained soils. It is also applied as a stabilizer in the in-situ treatment of hazardous waste. Once the colloidal silica solution is injected into contaminated soil, it moves through the pores inside the soil matrix, initiating the stabilization process. The viscosity of the colloidal silica mixture increases while it moves until solidifications. This process is called gelation and results in the creation of a gel barrier around contaminated …

Predicting Thermodynamic And Transport Parameters For Metal Contaminant Sorption To Hydrated Metal Oxides In Aquatic Systems, Paras Trivedi

Dissertations

Hydrated oxides such as HAO,'HFO, goethite, and BA40 are prevalent in soils and sediments as discrete particles or as coatings. These microporous oxides have large surface areas and high affmity for metal ions, and hence they act as both a sink and a source for anthropogenically released metal contaminants. To better understand risks posed by metals in the environment and to develop effective waste management programs, mechanistic models are needed to accurately predict their fate in soils and sediments.

To achieve this objective, sorption of metal ions Sr, Cd, Zn, Ni, and Ca to these oxides were studied with macroscopic …

Assessing The Economic Impact Of Aircraft Noise On Communities, Ithan B. Zimmer

Dissertations

The impact of aircraft noise on communities is complex and multi-dimensional. This matter cannot be resolved without careful analysis of a complex array of related problems and issues including the environment, the economy, and quality-of-life concerns of people living in proximity to airports or aircraft routes. The effects of community noise are widespread and varied. Impacts can include sleep and speech interference, activity interference, general annoyance, and property value decrease. In order to improve public policy and provide a foundation for additional research, it is imperative to establish the extent of a problem. Dollars are often the least common denominator …

Utilization Of Processed Fly Ash In Mortar, Walairat Bumrongjaroen

Dissertations

Grinding process is introduced to provide fine particles of coal fly ash that enhances the strength gain of cement mortars. It is discovered that grinding can make all the studied fly ashes more suitable for concrete use at higher replacement value than previously anticipated even when the effect of high carbon content is considered.

In this study, new mechanisms for strength gain of fly ash mortars are proposed. They are dispersion and nucleation, which are results from the presence of fly ash in the cement mortar. These effects are shown to enhance the hydration of cement. The pozzolanic action of …

Evaluation Of Environmental Characteristics Of Wtp Residuals For Disposal In Monofills, Ping Tian

Dissertations

Disposal of water treatment plant (WTP) have raised great concerns due to the stringent water quality standards and environmental regulations, and limited availability of land for ultimate disposal. The ultimate disposal of water treatment plant residuals by using monofill may be one of the most economical, and feasible options. Design and operation of such a monofill will be simple because of the uniformity of the characteristics of WTP residuals.

The objectives of this project were to determine the environmental characteristics of WTP residuals and to apply these characteristics for the design of monofills and development of the metal leaching model …

Effect Of Inorganic Salts On Adsorption Process, Pai-Yuan Horng

Dissertations

`Small amounts (0.0 M-0.01 M) of inorganic salts (sodium chloride, calcium chloride, and aluminum chloride) added to bituminous coal fly ash and granular activated carbon in batch adsorption treatment experiments indicates the possibility of enhancing the extent and rate of adsorption process.

Experiments were conducted on aqueous solutions of highly toxic and hazardous chemicals, those include : phenol, benzene, toluene, isopropyl alcohol, and methyl-isobutyl ketone. Single and multiple solute systems were examined separately. Removal of organic pollutants was measured using a Flame Ionization Detector Gas Chromatograph.

This study investigated the role of inorganic salts during the sorption process. The results …

Anaerobic Biodegradation Of Trichloroethylene With The Addition Of Sugar Using Activated Carbon-Fluidized Beds, Suxan Huang

Dissertations

Anaerobic biodegradation of trichloroethylene (TCE) was carried out in a two-stage granular activated carbon fluidized bed bioreactor. The intermediate products were identified as: dichloroethylene (DCE), vinyl chloride (VC), 1,2-dichloroethane (DCA) and chloroethane (CA). Of the three geometric isomers of DCE, the trans-1,2 dichloroethylene (TDCE) was found to be the most predominant species, The production of DCA suggested a diverted reaction sequence from the conventional sequential reductive dechlorination pathway postulated in the past literature. CA was believed to be a product of VC and/or DCA. The co-substrate glucose was implicated for this reaction specificity. Based on our data and on other's …

Multiyear Drought Simulation With Periodic-Stochastic Hydrologic Processes, Lankeswara Hemal Wijayaratne

Dissertations

Previous studies on multiyear droughts are often limited to the analysis of historic annual flow series. A major problem in these studies is the unavailability of long historic flow records, on which to perform the analysis. To overcome this difficulty, the present study has used synthetically generated mean annual flow series to suppliment the historic flows. For the purpose of generating flows, a general methodology was developed to propose a mathematical model based on the harmonic and stochastic analyses of the historic flow series. The main objective was to derive a large population of multiyear drought events from the generated …

Sorption And Desorption Of Organic Compounds By Flyash, Kashinath Banerjee

Dissertations

A sorbent treatment process has been developed which uses flyash as sorbent in the treatment of highly toxic and hazardous chemicals; these include: Alcohols, Aldehydes, Ketones and Aromatics. Batch, as well as dynamic, studies were performed, in different phases, during the investigation. Single and multiple solute systems were examined separately. The samples were analyzed using a Flame Ionization Detector Gas Chromatograph.

The result of this study demonstrates that isolation/ immobilization of the organic pollutants is technologically feasible by adsorbing the contaminants onto flyash. The residual carbon content of the flyash plays a very significant role during the treatment process. The …

The Effects Of Pressure On The Kinetics And Mechanisms Of The Bod Reaction, Peter Sereico

Dissertations

The research was concerned with the kinetics and mechanisms of BOD reduction due to pressurization. The initial investigations involved attempts to reproduce and interpret the results of previous investigators. Thereafter, actual wastewater samples were pressurized and changes in the wastewater characteristics were analyzed and recorded. Based on the findings, possible mechanisms for creating the changes noted were proposed.

To test the mechanisms considered, samples of pure compounds were prepared and pressurized. The results of this analysis eliminated all of the mechanisms but the actual one. The mechanism responsible for changes in BOD profile under pressure conditions is the hydrolysis of …