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Optimization Of Pcb Dechlorination With Palladized Magnesium In Marine And Freshwater Sediments, Irina Calante

Master's Theses and Capstones

Polychlorinated biphenyls (PCBs) are one of the most persistent and toxic pollutants in our environment today. Many rivers and lakes were heavily polluted with PCBs during the 1970s when their use and production was at their highest demand. Today, more than 30 years after they have been banned from production they continue to be one of the top priority contaminants. Their characteristic stability has made them very recalcitrant to physical, chemical and biological degradation. Remediation in soils and sediments are particularly more difficult due to the variability in the soil and sediment characteristics that affect how strongly PCBs are sorbed. …

Multi-Axial Anisotropic Material Behavior Using A Collection Of Yield Surfaces To Model The Stress-Space Coupling Phenomena, Mirjana Marusic

Master's Theses and Capstones

In the 1989 Loma Prieta earthquake in the San Francisco-Bay area and also the 1994 Northridge earthquake in Southern California, several buildings experienced significant damage because of inadequate member design. The existing codes of practice used for the structural design approximate the effects of nonlinear material behavior. This work formulates a nonlinear anisotropic material model for systems subjected to biaxial loading conditions such that the true nature of material degradation can be identified. This would aide structural designers in being able to predict accurate cyclic deformations under large earthquake events. The proposed model investigates anisotropic material behavior under bi-axial loading …

Treatment Of Dioxin/Furan And Pcn Contaminated Sediments With Palladized Magnesium, Linda M. Rauch

Master's Theses and Capstones

Sediments contaminated with dioxins/furans and polychlorinated naphthalenes (PCNs) have been the subject of little study although they are equal, if not more significant, contributors than PCBs to toxicity at selected sites. The reaction of a bimetal catalyst, palladized magnesium (Mg/Pd, 0.01% by weight Pd) with these contaminants was studied in solvents and sediments.

The reaction for single congeners in solvent resulted in 69-95% removal in 30 minutes. The detection of dibenzo-p-dioxin for the dioxin reaction and naphthalene/tetralin for the PCN reaction demonstrated dechlorination. A 24 hour sediment reaction with Mg/Pd resulted in 48% and 71% reduction for spiked sediments (500 …

Modeling Of A Soft Sensitive Marine Silty Clay Deposit For A Landfill Expansion Study, John Roche

Master's Theses and Capstones

An in situ testing program and finite element modeling of Presumpscot Formation glaciomarine clays in South Portland, Maine was undertaken as part of a landfill expansion feasibility study. The very soft sensitive silty clay foundation soils have been monitored during the 20 year lifespan of the landfill facility by an array of settlement platforms, inclinometers, piezometer clusters and periodic field shear vane tests. During this time large horizontal displacements have been observed at a discrete elevation corresponding to a zone of reduced undrained shear strength. Proposals call for a vertical expansion at the site above existing landfill cells. While this …

Post-Yield Nonlinear Behavior Of Structural Steel Beam-Column Elements, Josif Bicja

Master's Theses and Capstones

The presented method of analysis has the unique feature in its exact inclusion of the coupling between axial force, primary and secondary moments and their conjugate axial and bending strains, and, most importantly, the incorporation of the effect of curvature along the length of the member. Degradation of the material, once yielding has occurred at certain locations is accurately modeled, and the structural behavior for in-plane lateral dynamic loading of 2D shear frame beam-columns is predicted with particular reference to material nonlinearity and taking into consideration any geometrically nonlinear effects. Using detailed incremental procedures, the stress-strain relationship is derived for …

The Role Of The Schmutzdecke In Escherichia Coli Removal In Slow Sand And Riverbank Filtration, Michael C. Unger

Master's Theses and Capstones

A series of studies was conducted on laboratory scale sand columns under varying operational and design conditions with spiked concentrations of E. coli to investigate the role of the schmutzdecke, a biologically active layer that develops at the interface of the water and filter in slow sand filtration (SSF) and riverbank filtration (RBF). Results confirmed that E. coli removals in slow-rate biological filters occur primarily at the interface and are related to schmutzdecke ripening state, empty bed contact time, biological activity, temperature, and protistan abundance. Using a suite of analyses characterizing the biofilm growing on the schmutzdecke, no connection was …

Evaluation Of Characterization Techniques For Beneficial Use Of Underutilized Slag Materials, Thomas Sandy Weymouth

Master's Theses and Capstones

Wisely using byproduct materials in beneficial use applications such as highway construction is becoming more important in the United States as virgin materials are depleted and landfill capacity declines. Slags are byproducts of the steel and iron industries found in the Midwestern United States. Historically, many of these materials have historically been used in construction applications, but methods for characterizing their environmental risk are limited. This research considers a series of steps used to identify whether a particular slag poses an environmental or human health risk. The first step involves identifying the appropriate use of the material. The second step …

Properties Of Asphalt Mixtures Containing Rap, Aaron Marc Lachance

Master's Theses and Capstones

As the space available in landfills and the amount of high quality virgin aggregate has declined, the use of recycled asphalt pavement (RAP) in new asphaltic concrete mixtures has become common. This research examines how RAP affects virgin mixtures. A Superpave 19 mm mixture containing 0% RAP is used as the control for evaluating properties of mixes containing 15%, 25%, and 40% RAP. Volumetric analyses identified increases in both voids in the mineral aggregate (VMA) and voids filled with asphalt (VFA) at the 25% and 40% RAP levels, and that the amount of pre-heating of RAP prior to mixing influenced …

Performance Assessment Of Porous Asphalt For Stormwater Treatment, Joshua F. Briggs

Master's Theses and Capstones

The objective of this study is to assess the stormwater management capability of porous asphalt (PA) as a parking lot in Durham, New Hampshire. The site was constructed in 2004 and consists of a 4-inch PA pavement course overlying a porous media reservoir, including a fine-grained filter course. Cost per PA parking space ($2,200) was comparable to that for dense mix asphalt ($2,000). Pavement durability has been adequate. The lot retained or infiltrated 25% of precipitation (18 months) and 0.03 lb/sf of chloride (1 year). There was high initial surface infiltration capacity (IC) at two locations (1,000--1,300 in/hr), and moderate …