Engineering Commons^™

Microcosm Evaluation Of Natural And Biologically-Enhanced Abiotic Transformation Of Chlorinated Ethenes In Low Permeability Formations, Hao Wang

All Dissertations

Trichloroethene (TCE) is one of the most commonly found hazardous compounds at Superfund sites, especially in groundwater. Its volatility and toxicity pose a threat to drinking water safety and human health. In the past decades, research on the fate of TCE in the environment has shifted to contamination of low-permeability formations, for example fractured bedrock aquifers. TCE back-diffusion from low permeability zones and management of persistent TCE groundwater plumes caused by this long-term source zone pose major challenges for remediation.

Monitored natural attenuation (MNA) is a cost-effective remediation strategy that has gradually gained acceptance by regulators. Compared to extensive active …

Characterization Of Friction Element Welding Using Finite Element Modeling, Ankit Varma

All Dissertations

Friction element welding (FEW) has been advocated as a solution to weld different materials together, with the ability to join high-strength materials for a range of thicknesses with low input energy and a short processing time. This work develops a coupled thermal-mechanical finite element model to better understand the physical mechanisms involved in the process and to predict temperature and material flow during the process. Furthermore, microstructural analysis is performed for the steel layer using a scanning electron microscope and Vickers microhardness tester to understand the variation in its grain structure and hardness. Results from the finite element model and …

Propagation Of Uncertainty In Light-Frame Wood Buildings, Seyed Masood Hassanzadehshirazi

All Dissertations

Light-frame wood construction is the most common form of construction for residential and low-rise commercial buildings (e.g. hotels and motels) in North America. In these buildings, shearwalls are the primary systems resisting lateral loads induced by earthquakes and winds. Past earthquake events have revealed that the structural performance of nominally identical light-frame wood buildings varied significantly. Although much research has been conducted investigating the uncertainty in the performance of wood shearwalls and buildings under earthquake loading, the focus of many of these studies was on the uncertainty due to the earthquake motions, referred as earthquake-to-earthquake uncertainty, the influences of variability …

Controlling Steam Flood Migration With Air Injection Wells, Rex Hodges

All Dissertations

Steam flooding is an aggressive remediation technology for removing volatile organic chemical (VOC) sources that slowly dissolve into passing groundwater. Plume concentrations can be reduced, accelerating cleanup, and decreasing plume management costs. Steam injected in wells surrounding the source spreads outward and develops into a front that drives contamination to a system of groundwater pumping wells in the saturated zone and soil vapor extraction wells in the vadose zone. The process can be modeled with the non-isothermal multi-phase flow simulator T2VOC to include operation designs and factors at individual sites.
A pilot field-scale test at the Savannah River Site (SRS) …