Thesis (M.S.)--Florida State University, 2005. / Advisor: T. N. Krishnamurti, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed Jan. 26, 2006). Document formatted into pages; contains xi, 64 pages. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2005. / Includes bibliographical references (p. 123-127).

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 187-192).

Some of the more significant effects of global warming are manifested in the rise of temperatures and the increased intensity of hurricanes. This study analyzed data on Annual, January and July temperatures in Miami in the period spanning from 1949 to 2011; as well as data on central pressure and radii of maximum winds of hurricanes from 1944 to present. Annual Average, Maximum and Minimum Temperatures were found to be increasing with time. Also July Average, Maximum and Minimum Temperatures were found to be increasing with time. On the other hand, no significant trend could be detected for January Average, Maximum and Minimum Temperatures. No significant trend was detected in the central pressures and radii of maximum winds of hurricanes, while the radii of maximum winds for the largest hurricane of the year showed an increasing trend.

Widespread structural damage to critical facilities such as levees, buildings, dams and bridges during hurricanes has exemplified the need to consider multiple hazards associated with hurricanes as well as the potential for unacceptable levels of performance even if failure is not observed. These inadequate standards warrant the use of more accurate methods to describe the anticipated structural response, and damage for extreme events often termed performance based engineering (PBE). Therefore PBE was extended into the field of hurricane engineering in this study. Application of performance-based principles involves collection of the numerous hazards data from sources such as historical records, laboratory experiments or stochastic simulations. However, the hazards associated with a hurricane typically include spatial and temporal variation therefore, more detailed collection of data from each hazard of this loading spectrum is required. At the same time, computational power and computer-aided design have advanced and potentially allows for collection of the structure-specific hazard data. This novel technique, known as computational fluid dynamics (CFD), was applied to the wind and wave hazards associated with hurricanes to accurately quantify the spectrum of dynamic loads in this study. Numerical simulation results are presented on verification of this technique with laboratory experimental studies and further application to a typical Florida building and bridge prototype. Both the time and frequency domain content of random process signals were analyzed and compared through basic properties including the spectral density, autocorrelation, and mean. Following quantification of the dynamic loads on each structure, a detailed structural iv FEM was constructed of each structure and response curves were created for various levels of hurricane categories. Results show that both the time and frequency content of the dynamic signal could be accurately captured through CFD simulations in a much more cost effective manner than laboratory experimentation. Structural FEM models showed the poor performance of two coastal structures designed using deterministic principles, as serviceability and strength limit states were exceeded. Additionally, the response curves created for the prototype structure could be further developed for multiple wind directions and wave periods. Thus CFD is a viable option to wind and wave laboratory studies and a key tool for the development of PBE in the field of hurricane engineering.

Arbuscular mycorrhizal fungi, colonizing over 80% of all plants, were long thought absent in wetlands; however, recent studies have shown many wetland plants harbor arbuscular mycorrhizae (AM) and dark septate endophytes (DSE). Wetland services such as biodiversity, shoreline stabilization, water purification, flood control, etc. have been estimated to have a global value of $14.9 trillion. Recognition of these vital services is accompanied by growing concern for their vulnerability and continued loss, which has resulted in an increased need to understand wetland plant communities and mycorrhizal symbiosis. Factors regulating AM and DSE colonization need to be better understood to predict plant community response and ultimately wetland functioning when confronting natural and human induced stressors. This study focused on the effects of water quality, hydrology, sedimentation, and hurricanes on AM and DSE colonization in three wetland species (Taxodium distichum, Panicum hemitomon, and Typhal domingensis) and plant communities of coastal wetlands in Southeast Louisiana and effects of an antimicrobial biocide, triclosan (TCS), on AM (Glomus intraradices) spore germination, hyphal growth, hyphal branching, and colonization in fresh water wetland plants (Eclipta prostrata, Hibiscus laevis, and Sesbania herbacea) from bottom land hardwood forest in north central Texas. The former, mesocosm studies simulating coastal marsh vegetation ran for five years. In the latter studies, AM spores and wetland plants were exposed to 0 g/L, 0.4 g/L, and 4.0 g/L TCS concentrations in static renewal and flow through exposures for 21 and 30 days, respectively. AM and DSE colonization was significantly affected by individual and interactions of four independent variables in mesocosm experiments. Similarly, spore germination, hyphal growth, hyphal branching, and AM colonization in selected wetland plants were significantly lowered by exposure to the TCS at environmentally relevant concentrations. However, levels of effects were plant species and fungal propagules specific. My results showed that natural and human induced alterations in environmental factors and chemical contaminants can significantly impact levels of mycorrhizal spore germination, colonization, and spore density in coastal and freshwater wetland plants. The resulting impacts on plant community structure and ecosystem function require further study.

No description available.

Thesis (M.S.)--Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.

A common issue with the power grid during natural disasters is low availability. Many critical applications that are required during and after natural disasters, for rescue and logistical operations require highly available power supplies. Microgrids with distributed generation resources along with the grid provide promising solutions in order to improve the availability of power supply during natural disasters. However, distributed generators (DGs) such as diesel gensets depend on lifelines such as transportation networks whose behavior during disasters affects the genset fuel delivery systems and as a result affect the availability. Renewable sources depend on natural phenomena that have both deterministic as well as stochastic aspects to their behavior, which usually results in high variability in the output. Therefore DGs require energy storage in order to make them dispatchable sources. The microgrids availability depends on the availability characteristics of its distributed generators and energy storage and their dependent infrastructure, the distribution architecture and the power electronic interfaces. This dissertation presents models to evaluate the availability of power supply from the various distributed energy resources of a microgrid during natural disasters. The stochastic behavior of the distributed generators, storage and interfaces are modeled using Markov processes and the effect of the distribution network on availability is also considered. The presented models supported by empirical data can be hence used for microgrid planning. / text

The most critical hazards impacting the world today are the affects of climate change and global warming. Scientists have been studying the Earth's climate for centuries and have come to agreement that our climate is changing, and has changed, many times abruptly over the history of our planet. This research focuses on the impacts of global warming related to increased hurricane intensities and their surge responses along the coast of the State of Louisiana. Surge responses are quantified for storms that could potentially occur under present climate but 50 years into the future on a coast subjected to current erosion and local subsidence effects. Analyses of projected hurricane intensities influenced by an increase in sea surface temperatures (SSTs) are performed. Intensities of these storms are projected to increase by 5% per degree of increase in SSTs. A small suite of these storms influenced by global warming and potentially realized by abrupt climate changes are modeled. Simulations of these storms are executed using a storm surge model. The surges produced by these storms are significantly higher than surges produced by presentday storms. These surges are then compared to existing surge frequency distributions along the Louisiana coast.