Engineering Commons^™

Calcium Carbonate Formation In Energy-Related Subsurface Environments And Engineered Systems, Qingyun Li

McKelvey School of Engineering Theses & Dissertations

Geologic CO2 sequestration (GCS) in subsurface saline aquifers is a promising strategy to mitigate climate change caused by increasing anthropogenic CO2 emissions from energy production. At GCS sites, interactions between fluids and geomedia are important because they can affect CO2 trapping efficiency and the safety of CO2 storage. These interactions include the dissolution and precipitation of minerals. One of the most important minerals is calcium carbonate, because it can permanently trap CO2.

In this work, Portland cement was used as a model geomedium to investigate the chemical reactions, mechanical alterations, transport of reactive fluids, and the interplay of all these …

Sizing An Anaerobic Digester In A Rural Developing World Community: Does Household Fuel Demand Match Greenhouse Gas Production?, Ronald Keelan Greenwade

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion is the process by which organic carbon is converted into biogas in the form of carbon dioxide (CO₂) and methane (CH₄). Both of these products are greenhouse gases that contribute to global warming. Therefore if anaerobic reactors are improperly maintained and biogas is leaked or intentionally released into the atmosphere because biogas production exceeds household demand, these reactors may become generators of greenhouse gas emissions instead of sustainable energy producers. The objective of this research was to develop a framework to assess if the demand for biogas by a rural adopter of an anaerobic …

Use Of Sacrificial Embankments To Minimize Bridge Damage From Scour During Extreme Flow Events, Matthew Willi Brand

Graduate College Dissertations and Theses

The leading cause of bridge failure has often been identified as bridge scour, which is generally defined as the erosion or removal of streambed and/or bank material around bridge foundations due to flowing water. These scour critical bridges are particularly vulnerable during extreme flood events, and pose a major risk to human life, transportation infrastructure, and economic sustainability. Climate change is increasing the intensity and persistence of large flow events throughout the world, further straining bridge infrastructure. Retrofitting the thousands of undersized and scour critical bridges to more rigorous standards is prohibitively expensive, and current countermeasures inadequately address the core …