Physical Sciences and Mathematics Commons^™

The Impacts Of Wind On Coastal Trees, Julian Halil

All Theses

Trees in hurricane-prone areas are exposed to severe winds and flooding. We studied the physiological and structural responses of forested wetland trees in relation to wind stress. We evaluated the windfirmness of two forested wetland tree species. Baldcypress was chosen because of high survival in post-hurricane studies. In contrast, laurel oak co-occurs with baldcypress yet resists hurricane-force winds poorly. In a static winching study, we quantified the critical turning moment (Mcrit) required to topple both species. Mcrit increased with trunk diameter at breast height (DBH) and crown size. Baldcypress and laurel oak demonstrated similar Mcrit, but regression models indicate baldcypress …

A Framework For Statistical Modeling Of Wind Speed And Wind Direction, Eva Murphy

All Dissertations

Atmospheric near surface wind speed and wind direction play an important role in many applications, ranging from air quality modeling, building design, wind turbine placement to climate change research. It is therefore crucial to accurately estimate the joint probability distribution of wind speed and direction. This dissertation aims to provide a modeling framework for studying the variation of wind speed and wind direction. To this end, three projects are conducted to address some of the key issues for modeling wind vectors.\\

First, a conditional decomposition approach is developed to model the joint distribution of wind speed and direction. Specifically, the …

Probing The Structure Of Water On Surfaces: From Water Absorption To Ice Nucleation, Jiarun Zhou

All Dissertations

Water, essential for all life forms, is the most abundant, simple, yet mysterious molecule in the world. This molecule, consisting of only three atoms, behaves in unexpectedly different ways with the change of environment. In the past, studies of water under different conditions (temperature, pressure, on the surfaces, with confinement) have been conducted using experimental and computational methods. However, the influence of a given environment on water properties is yet to be fully understood. This dissertation studies water at complex interfaces (surfaces with various chemistry and physics properties) in both the liquid and crystalline states. Various heterogeneous systems used to …

Studies Of The Ionosphere-Thermosphere Responses To Multi-Scale Energy Deposition Processes, Haonan Wu

All Dissertations

The Ionosphere-Thermosphere (I-T) system is greatly affected by the magnetospheric energy deposition from above and subjected to forcing from the lower atmosphere simultaneously. A central problem in studying the coupled I-T system is to analyze the multi-scale processes naturally embedded in both ways. Magnetospheric energy input such as auroral precipitation and electric field demonstrates multi-scale structures during magnetic storms, resulting in multi-scale I-T responses when deposited into the I-T system. To better quantify the multi-scale aurora and electric field, we developed a new data assimilation model based on a multi-resolution Gaussian process model to synthesize empirical models and observational data …

Green On The Map - The Influence Of Conservation Easements On The Naturalness Of Landscapes In The United States, Nakisha Fouch

All Dissertations

Large protected areas have long been the cornerstone of conservation biology, however, in an era branded by the human dominance of ecosystems, regional landscape structure and function are often a consequence of accumulated land-use decisions that may or may not include a nod to conservation planning. With underrepresentation of habitats in publicly protected areas, attention has focused on the function of alternative land conservation mechanisms. Private conservation easements (CEs) have proliferated in the United States, yet assessing landscape-level function is confounded by holder and donor intent, national and regional policy, regional landscape contexts, varying extents, resolution, and temporal scale. Over …

Uncertainty Of Dimensional Measurments Obtained From Self-Initialized Instruments, Vincent Lee

All Dissertations

Precision dimensional measurement instruments often contain sensors that can only measure displacement of a moving body from some reference position. In order to measure the length of an object they often require a calibrated artifact to initialize their measurement sensors so that they may provide an absolute measurement instead of displacement. Instruments which can realize a null value, i.e. zero length, don't require one; however instruments which can't need to reference an object of known size. These calibration artifacts also serve as part of the chain of metrological traceability.
The group of instruments presented in this dissertation can self-initialize by …

Reduction Of Rocket-Borne Atmospheric Density Measurements Using Monte Carlo Simulation, Travis Gaulden

All Theses

The HEX II atmospheric rocket experiment, conducted near 9:30 U.T. February 14, 2007 from the Poker Flat Rocket Range in Alaska was designed to lead to a better understanding of density and velocity gradients in the lower thermosphere. In a supporting role to this mission, cold cathode ionization gauges recorded composite density along three rocket payload trajectory paths from 90 km to 200 km. Rocket-borne instruments experience near sonic to hypersonic velocities and encounter a range of viscous, slipflow, and collisionless flow conditions at these heights. These variable conditions necessitate the use of tailored analytic expressions appropriate to the flow …

Functional Characterization Of Calcium Dependent Protein Kinase 32 From Arabidopsis, Rucha Karve

All Dissertations

Calcium-dependent protein kinases (CPKs) are major plant Ca2+ sensors, many of which have roles in plant stress responses. The Arabidopsis genome encodes 34 CPK isoforms. Here we report characterization of AtCPK32 gene function. Analysis of transgenic plants expressing pCPK32-GUS shows that CPK32 is highly expressed in roots, pollen and embryo, as well as leaf hydathodes, and the abscission zone of mature siliques. Real time RT-PCR and promoter expression patterns show that CPK32 is responsive to abiotic and biotic stresses. Plants treated with salt, ABA, osmotic stress (PEG), wounding, and flagellin 22 peptide show up-regulation of CPK32 upon these stress treatments. …

A Study Of The Mesosphere-Lower Thermosphere: Noctilucent Cloud Observations And Rocket Borne Density Measurements, Shelton Simmons

All Theses

Herein, a study of a noctilucent cloud, NLC, display from 17 July 2007 is analyzed. A photogrammetric analysis was applied to time lapsed photographs taken from two observation sites, RŸgen and KŸhlungsborn, Germany. Both Kelvin-Helmholtz instabilities and internal gravity waves were identified during the NLC display based on the typical characteristics of such waves in the mesopause region. With the two observation sites, the location of details can be identified with an accuracy of ±0.125¡ longitude and ±0.5¡ latitude. A gravity wave with a wavelength of 50km and Kelvin-Helmholtz instability or gravity wave of wavelength 16.5km were observed. The 16.5km …

Analysis Of The Neutral Wind Profiles From The Hex Ii Experiment, Tyler Scott

All Theses

The HEX II sounding rocket experiment was carried out on February 14, 2007, during active geomagnetic conditions. Three rockets released trimethyl aluminum (TMA) chemical tracer trails to measure the neutral winds. Three neutral wind profiles obtained from the upleg trails are presented. The profiles are characterized by a strong wind peak around 113 km altitude in the northwestward direction. Below the peak, the winds exhibit strong shear and a smaller wind peak at around 103 km in the southeastward direction. The wind magnitudes are too strong to be attributed to tidal forcing. Above 120 km the winds are consistently to …

Iron Sequestration In Lake Sediments From Artificial Hypolimnetic Oxygenation: Richard B. Russell Reservoir, Amanda Elrod

All Theses

The Upper Savannah River watershed has numerous impoundments, and the three largest hydroelectric reservoirs, from north to south, are Hartwell, Richard B. Russell, and J. Strom Thurmond Lakes. During the summer months, these reservoirs undergo thermal and chemical stratification, which results in the formation of cool, hypoxic/anoxic hypolimnia and warm, oxic epilimnion. To maintain fisheries habitat, the United States Army Corps of Engineers operates a hypolimnetic oxygenation system in the forebay of Richard B. Russell Lake. The purpose of this system is to improve the water quality of the releases from Richard B. Russell Dam by maintaining a dissolved oxygen …

Water Quality Dynamics Of Lake James In The Catawba River Basin Of North Carolina, Susan Stokes

All Dissertations

Lake James is the uppermost hydropower reservoir in the Catawba River drainage in North Carolina. The Lake James Assessment (LJA) was a descriptive study initiated between Clemson University and Duke Energy Corporation to explore the physical, chemical and biological dynamics of this oligotrophic reservoir from spring 1997 through fall 1999 (Schindler 1997). The goals of this study were to ascertain the primary drivers for the chemical dynamics of Lake James, to assess the quantities of constituents entering and leaving the reservoir, where these chemicals were incorporated within the reservoir basins, and to evaluate the efficacy of the LJA chemical budget …

Responses Of Problematic Cyanobacteria To Exposures Of Copper Containing Algaecides, O'Niell Tedrow

All Theses

Cyanobacteria (blue-green algae) are associated with production of potent hepatotoxins (Microcystis; microcystin) and dense surface and benthic mats (Lyngbya), which impede critical water resource usages. Water resource managers are in need of effective and efficient treatment techniques for these problematic algae in field situations. Applications of algaecides are considered in situations where algal problems become acute or when critical water usages are threatened. However, laboratory data are needed that accurately predict responses of algae prior to field-scale algaecide applications. Site water and algae were used in laboratory algal toxicity experiments to predict responses of the target alga following an algaecide …

Mesosphere And Lower Thermosphere Neutral Winds Observations Using Rocket-Released Chemical Trails At Poker Flat, Alaska, Tianyu Zhan

All Dissertations

Sounding rocket campaigns ARIA I through ARIA IV, CODA 2, HEX 1, JOULE 1 and JOULE 2 all carried out at Poker Flat Research Range at Alaska, covering the geomagnetic condition from quiet to highly disturbed. Trimethyl aluminum (TMA) were released during the rocket flights to study the mesosphere and lower thermosphere neutral wind at high-latitude region. The results of horizontal neutral wind profiles are presented. The comparison shows that under disturbed condition the wind velocity is stronger and the jet feature at the bottom side of wind maximum with unstable wind shear is lifted to a higher altitude. Under …

Wind Damage And Salinity Effects Of Hurricanes Katrina And Rita On Coastal Baldcypress Forests Of Louisiana, William Conner, Thomas W. Doyle, Richard H. Day, Ken W. Krauss, Christopher M. Swarzenski

Publications

The frequency of hurricane landfall in a given coastal stretch may play a more important role in the ecology of coastal forests than previously thought because of direct and indirect impacts of fallen trees and the introduction of salt water that lingers long after the storm passes. Findings show that surge events can inundate interior freshwater forests many miles from the coast and elevate soil salinities twofold to threefold. These elevated salinities may contribute to delayed mortality of certain tree species and set the stage for eventual forest decline and dieback.

Science And The Storms: The Usgs Response To The Hurricanes Of 2005 - Chapter Six: Ecological Impacts, William Conner, Stephen Faulkner, Wylie Barrow, Brady Couvillion, Lori Randall, Michael Baldwin

Publications

Ecological impacts from the hurricanes of 2005 affected both vegetation and the animals that depend on coastal habits on land and in water. Discussed in this section are migratory birds, coastal marsh vegetation, chenier forests, coastal floodplain forests, mangrove forests, estuaries, and the endangered manatee.

Onset And Persistence Of Biogenic Meromixis In A Filling Pit Lake-A Limnological Perspective , Oscar Flite

All Dissertations

Open pit mining usually results in a void that, over time, fills with water and becomes a pit lake. The goal for pit lakes is to create sustainable systems that positively contribute to local and regional watersheds. One long-standing hypothesis for attaining the goal of sustainability has been to create and maintain meromictic lakes (lakes that do not completely mix on a yearly cycle). It is believed that meromixis minimizes atmospheric oxygen exposure to pit walls and concomitant acid generation and minimizes reentrainment of metals to the upper waters during seasonal mixes. This seems to be a reasonable goal but …

The Effect Of Water Droplet Oscillations On The Scavenging Efficiency Of Micron Sized Particles, Raymond Mcdonnell

All Theses

It has been hypothesized that drop oscillations and vortex shedding within the droplet wake affect the scavenging efficiency, E, of particles. However, no conclusive results have been presented on the effect these phenomena might have on particle scavenging. To address this need, experiments were conducted using oscillating water drops and water drops damped by the addition of glycerol. The scavenging efficiencies were measured for millimeter-sized droplets scavenging micron-sized particles. These results show that E is increased by drop oscillations where the particle diameter is large, but E is decreased by these oscillations when the particle diameter is small.