Physical Sciences and Mathematics Commons^™

The Tropical Cyclone Diurnal Cycle, Jason Paul Dunion

Legacy Theses & Dissertations (2009 - 2024)

The research presented in this thesis explores a phenomenon referred to as the tropical cyclone (TC) diurnal cycle (TCDC) and presents satellite, numerical modeling, and observational perspectives pertaining to how it can be monitored, its evolution in time and space, its relevance to TC structure and intensity, and how it manifests in numerical simulations of TCs. Infrared satellite imagery was developed and used to investigate diurnal oscillations in TCs and finds a diurnal pulsing pattern that occurs with notable regularity through a relatively deep layer from the inner core to the surrounding environment. A combination of satellite, numerical model simulations, …

Numerical Study Of Canopy Flows In Complex Terrain, Xiyan Xu

Dissertations, Theses, and Capstone Projects

Canopy flow plays a substantial role in regulating atmosphere-biosphere exchanges of mass and energy. The worldwide FLUXNET has been developed to quantify the net ecosystem exchange of mass and energy through fluid dynamics in and above vegetation canopy using tower-based eddy covariance (EC) technique. However, EC measurements are subject to advection errors in complex terrain, particularly during nights when atmospheric stability is strong. Because EC measurements are one-dimensional (1D), three-dimensional (3D) air movement, CO2 transport, and temperature variation around the instrumented tower are unknown. We employ a Computational Fluid Dynamics (CFD) model to investigate the impact on CO2 transport of …

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …

An Investigation Of Deformation Structures And Their Tectonic Significance Across The Grenville Front Tectonic Zone In The Vicinity Of Sudbury, Ontario, Canada, Changcheng Li

Electronic Thesis and Dissertation Repository

The Grenville Front Tectonic Zone (GFTZ) is a polyphase deformation belt in the northwest of the Grenville Province which was shaped in the continent-continent-collision-induced Grenvillian Orogeny.

This thesis focuses on the evolution of deformation fabrics in the GFTZ between the Sudbury Basin and French River in Ontario, Canada. Geological mapping using a new digital mapping system was conducted within this segment of the GFTZ, in its northwest vicinity in the Southern Province, and in its southeast vicinity in the Grenville Province. The new digital mapping system includes a personal digital assistant equipped with an internal GPS and a mobile GIS …

Phreatomagmatic Activity On The Moon: Possibility Of Pseudocraters At Mare Frigoris, Jose Humberto Garcia

Open Access Theses & Dissertations

The discovery of water on the Moon raises the possibility that lava-water, or phreatomagmatic, interactions have occurred on the lunar surface in the past. Such interactions may have formed pseudocraters, crater-like landforms that result from steam explosions that occur when lava flows come in contact with surface or near-surface water or ice. We present a study of Mare Frigoris, a volcanic plain just north of the Mare Imbrium impact basin on the Moon. Clusters of irregular, circular features on the basaltic lava flows in this area resemble pseudocrater fields in Iceland, and they are located in a region with inferred …

Detailed Modeling Of Soot Size Distribution Evolution And Pollutant Formation Inside Aircraft And Diesel Engines, Chowdhury Golam Moniruzzaman

Legacy Theses & Dissertations (2009 - 2024)

Combustion emission of soot and pollutant gas species contributes to poor regional air quality near emission sources and to climate change. It is important to understand the formation mechanism and time evolution of these pollutants inside the combustion engine, through detailed modeling of combustion chemistry and microphysics as well as comparison with observation. In this thesis, two multi-zone gas parcel combustion engine models, one for aircraft engines and another for diesel engines, have been developed to study soot size distribution evolution and pollutant formation inside the engines as well as emissions. The models take into account size-resolved (sectional) soot aerosol …

Modeling The Impacts Of Pulsed Riverine Inflows On Hydrodynamics And Water Quality In The Barataria Bay Estuary, Anindita Das

LSU Doctoral Dissertations

Eutrophication and coastal wetland loss are the major environmental problems affecting estuaries around the world. In Louisiana, controlled diversions of the Mississippi River water back into coastal wetlands are thought to be an important engineering solution that could reverse coastal land loss. There are concerns, however, that freshwater diversions may increase nutrient inputs and create severe eutrophication problems in estuaries and wetlands adjacent to the diversion sites. My dissertation research concerns modeling the effects of the observed and hypothetical freshwater diversion discharges on the hydrodynamics, salinity and water quality in the Barataria estuary, a deltaic estuary in south Louisiana. This …

Numerical Modeling Of Time-Lapse Seismic Experiments To Monitor Co2 Sequestration In A Layered Basalt Reservoir, Murari Khatiwada

Boise State University Theses and Dissertations

Instead of allowing carbon dioxide (CO₂) generated from the burning of hydrocarbons to escape into the atmosphere, CO₂ can be captured and stored. For the long term mitigation of the increasing amount of CO₂ emissions, its sequestration in geological formations is promising. As a measure, its short and long term monitoring is equally important for environmental and health safety issues. The seismic method is proposed as a non-invasive monitoring technique for geological sequestration of CO₂. Based on the positive results obtained from reservoir monitoring during enhanced oil recovery with CO₂ floods, geoscientists plan …

Computational Simulation Of Strain Localization: From Theory To Implementation, Shouxin Wu

Doctoral Dissertations

Strain localization in the form of shear bands or slip surfaces has widely been observed in most engineering materials, such as metals, concrete, rocks, and soils. Concurrent with the appearance of localized deformation is the loss of overall load-carrying capacity of the material body. Because the deformation localization is an important precursor of material failure, computational modeling of the onset and growth of the localization is indispensable for the understanding of the complete mechanical response and post-peak behavior of materials and structures. Simulation results can also be used to judge the failure mechanisms of materials and structures so that the …

Barrier Island Migration Over A Consolidating Substrate, Julie Dean Rosati

LSU Doctoral Dissertations

Barrier islands that overlie a compressible substrate load and consolidate the underlying subsurface. Through time, the elevation and aerial extent of these islands are reduced, making them more susceptible to inundation and overwash. Sand washed over the island and onto back-barrier marsh or into the bay or estuary begins the consolidation process on a previously non-loaded substrate, with time-dependent consolidation a function of the magnitude of the load, duration of load, and characteristics of the substrate. The result is an increase in the overwash, migration, breaching, and segmentation of these islands. This research determined the degree to which consolidation affects …

Frontal Variability In Drake Passage - A Modeling Study, Bin Zhang

OES Theses and Dissertations

The Antarctic Circumpolar Current (ACC) features three major fronts: the Sub-antarctic Front (SAF), the Polar Front (PF), the Southern ACC Front (SACCF). The locations of these fronts are not stable. The PF can shift away from its historical mean locations on the order of 100 km. The ACC transport in Drake Passage varies over a large range (50 to 60 Sv). Numerical simulations with the Regional Ocean Modeling System are carried out to study the frontal variability under the influence of ACC transport, local wind stress and bottom topography in Drake Passage.

Front-embedded numerical experiments are carried out without surface …

Design And Optimization Of Nano-Optical Elements By Coupling Fabrication To Optical Behavior, Raymond Rumpf

Electronic Theses and Dissertations

Photonic crystals and nanophotonics have received a great deal of attention over the last decade, largely due to improved numerical modeling and advances in fabrication technologies. To this day, fabrication and optical behavior remain decoupled during the design phase and numerous assumptions are made about "perfect" geometry. As research moves from theory to real devices, predicting device behavior based on realistic geometry becomes critical. In this dissertation, a set of numerical tools was developed to model micro and nano fabrication processes. They were combined with equally capable tools to model optical performance of the simulated structures. Using these tools, it …

Thermal And Mechanical Effects Of A Shallow Asthenosphere In The Acadian Orogen: An Investigation Through Numerical Modeling, Lucy E. Brown

Electronic Theses and Dissertations

A high-temperature region associated with Acadian deformation extends 200 km through north-central New England. The scale of this heat source is investigated in order to better understand the rheology and mechanics of deforming orogens. In central Maine, on the boundary of the high-temperature region, isograds in pelitic rocks are normal to the accretionary structures and record a steep northeast-southwest thermal gradient. The isogradic sequence, geobarometry, and the mineral assemblages indicate low-pressure, high-temperature metamorphism, moderately low pressures of 3 kbar, and temperatures ranging from 600º to 450ºC over a 10 km region. The spacing between these isograds and the temperature at …

Simulating The Oil Spill In The Arabian Gulf Marine Environment: A Risk Assessment In Association With Uae Coastal Desalination Plants, Abubaker Awad El-Hakeem

Theses

The current study is directed towards the development of oil spill hazard contour maps for the prediction of oil spill travel times and critical wind directions in association with major strategic desalination plants in United Arab Emirates. Five desalination plants in are selected along the UAE coastline to be the potential destination points of oil spill hazards. These plants are AI-Shuwayhat, AI-Mirfa, Umm AINar & Taweelah, Jebel Ali and AI-Layah.

In order to reach the set target, a coastal hydraulics simulation model is employed to adopt the real sea-state dynamic conditions. The hydrodynamic simulated results are tuned and tested against …

Fluvial Evolution Of The Garonne River, France: Integrating Field Data With Numerical Simulations, Robin Rene Lancaster

LSU Master's Theses

The Garonne River of southwestern France presents a unique opportunity to study the controls on long-term incision and terrace formation within a large-scale fluvial system. The Garonne heads in the Pyrenees, flows through the Aquitaine Basin, and discharges into Atlantic Ocean via the Gironde Estuary/Bay of Biscay. From field data, three terrace complexes were identified and traced for >251 km from the base of the Pyrenees to the onset of tidal influences. Each complex is separated from adjacent complexes by scarps >10 m and represent 10s to 100s kyrs during which time the river occupied a finite elevational range within …

The Photosynthetic Action Spectra Of The Phytoplankton And Their Role In Governing Spatial And Temporal Distribution: A Numerical Modeling Approach, William Morrow Willis

OES Theses and Dissertations

In the present study a numerical modeling approach is employed to examine the role of division spedific differences in photosynthetic action spectra in governing the relative size of diatom and dinoflagellate carbon synthesis along various marine light regime gradients. A radiative transfer model taking into account both Rayleigh and Mie atmospheric optical properties is employed to define the light regime incident on the sea surface. The hydrospheric light regime is defined by an exponential decay model with a correction for diffuse back scatter. Taken together, the atmospheric and hydrospheric models define the spectral composition and intensity of light in the …