Engineering Commons^™

Toward Understanding The Physiological Determinants Of Microbial Competitiveness In Methanogenic Processes, Si Chen

Doctoral Dissertations

Methanogenesis is of great significance in both natural and engineered processes. Anaerobic digestion technology represents the engineering-scale implementation of methanogenesis in waste treatment processes. Despite the broad application of anaerobic digestion as a common waste treatment option, much remains to be learned on the anaerobic food web underlying methanogenesis for more effective process modeling and control.

Following an initial screening of various substrates, six continuous lab-scale anaerobic digesters were developed with animal waste as the substrate. The linkage between microbial community composition and process performance was studied by initiating process imbalance with organic overloading. As a result, accumulation of short …

Impacts Of Climate Change On The Evolution Of The Electrical Grid, Melissa Ree Allen

Doctoral Dissertations

Maintaining interdependent infrastructures exposed to a changing climate requires understanding 1) the local impact on power assets; 2) how the infrastructure will evolve as the demand for infrastructure changes location and volume and; 3) what vulnerabilities are introduced by these changing infrastructure topologies. This dissertation attempts to develop a methodology that will a) downscale the climate direct effect on the infrastructure; b) allow population to redistribute in response to increasing extreme events that will increase under climate impacts; and c) project new distributions of electricity demand in the mid-21^st century.

The research was structured in three parts. The first …

Stability, Erosion, And Morphology Considerations For Sustainable Slope Design, Isaac Andres Jeldes Halty

Doctoral Dissertations

The construction of more natural and sustainable earth slopes requires the consideration of erosion and runoff characteristics as an integral part of the design. These effects not only result in high costs for removal of sediment, but also a profound damage to the ecosystem. In this dissertation, innovative techniques are developed such that more natural appearing slopes can be designed to minimize sediment delivery, while meeting mechanical equilibrium requirements. This was accomplished by: a) examining the fundamental failure modes of slopes built with minimum compaction (FRA) to enhance quick establishment of forest, b) investigating the geomechanical and erosion stability of …