Millions of people in low-lying areas are already affected by flooding, and the number will increase substantially in the future. Tidal flooding, the form of flooding caused by a combination of high tides and sea level rise to overcome protection levels, can cause damage and inconveniences such as road closures, overwhelmed drainage systems, and infrastructure deterioration from water damage. Tidal flooding already occurs annually in cities along the U.S. east coast, most notably Miami. However, the time it will take for other regions globally to begin to experience tidal flooding has not yet been assessed. Therefore, there is a limited understanding of how and when human populations will be exposed to this type of flooding. Tide gauge data from the GESLA-2 data base are used to obtain information about the highest astronomical tide (HAT) and extreme value statistics for 571 locations globally. For a complete spatial analysis, modelled water levels from the Global Tide and Surge Reanalysis (GTSR) are also used. Estimated protection levels are extracted from the DIVA database and translated to absolute heights based on the extreme value statistics of high water levels. This analysis is based on calculating the difference between the existing protection level and HAT, which indicates how much sea levels can rise before tidal flooding occurs, and evaluating in what decade this is expected to happen under different sea-level rise (SLR) scenarios. Tidal trends from the nodal and perigean are also taken account and used to modify 1000 different sea level rise scenarios to provide a more comprehensive analysis of possible tidal flooding years. Our results indicate that tidal flooding may occur within a few decades in many locations (under the assumption that no adaptation will take place), and therefore awareness should be heightened so that actions can be taken to minimize the impacts.

Due to the global loss of tidal marsh area, potential anthropogenic and natural disturbances to these systems, and coastal marshes’ affinity for trapping environmental pollutants, understanding how marsh birds inhabiting these ecosystems will adapt to these changes is paramount. To quantify future changes, I first needed to have something to compare against – baseline estimates. To this end, I performed distance sampling line transect surveys during the nonbreeding season to estimate species-specific population abundance, density, and habitat associations and captured two species of marsh bird, Clapper Rail (Rallus crepitans) and Seaside Sparrow (Ammospiza maritima), to estimate baseline ingestion of one such environmental pollutant – microplastics. By providing the first baseline population and density estimates for numerous nonbreeding marsh birds, my findings suggest that the tidal marshes of Mississippi provide critical habitat for many of these species. Additionally, I was able to document the first evidence of microplastic ingestion by resident tidal marsh birds.

The research detailed in this study focuses on the determination of an appropriate objective function to aid parameter estimation when simulating areas influenced by tidally varying flows. Three objective functions that are measures of how well the model results match field data at several locations and times were tested. A set of test cases is developed to represent tidally influenced systems and allow for the testing of the objective functions. These objective functions were tested by computing their values and comparing them for the various estimated parameters. Based on results of the first method of testing a further analysis was performed using PEST, an automatic parameter estimation tool. A weighted least squares of the velocity and water surface values with a weight function on the velocity term based on the shallow water equations is found to be a reasonable objective function at this point in the research.

No description available.

No description available.

Administration of nasal cannula therapy tasks providers with periodically monitoring their patients and adjusting settings according to patient needs. Conventionally, providers monitor a patient's oxygen demand using pulse oximetry and a qualitative assessment of the patient's work of breathing. The motivation for this research is to augment the traditional qualitative assessment of work of breathing with a quantitative measurement of a patient's tidal volume, the volume of air inhaled with each breath. This thesis presents a novel approach to measure tidal volume using a nasal cannula with built-in pressure sensors. Pressure waveforms obtained from continuous measurement of the pressure at the tip of the cannula are used to estimate nasal flowrates, and these nasal flowrates are time-integrated to estimate tidal volumes. Computational fluid dynamics (CFD) models were used to simulate fluid flow in a simplified nasal passage undergoing nasal cannula therapy. These simulations used a range of flow conditions characteristic of both low-flow and high-flow nasal cannula treatments. The simulations produced a transformation from cannula tip pressure to instantaneous nasal flowrate, and this transformation was evaluated using a matching empirical experiment. This empirical experiment used a matching physical geometry with a similar range of flow conditions, and the transformation obtained from CFD was able to estimate the actual tidal volumes with 85% accuracy. This study showed that continuous pressure measurement at the tip of a nasal cannula produces enough information to estimate nasal flowrates and tidal volumes. No similar studies were found during the literature review, so an accuracy of 85% is promising for this stage. If this technique could be made more accurate and deployed in an unobtrusive way, the resulting nasal cannula device could be used to continuously, comfortably monitor patients' tidal volumes. / Master of Science / Oxygen therapy is the most common prescription in hospitals across the United States, and the most common form of oxygen therapy is nasal cannula therapy. Administration of nasal cannula therapy requires providers to periodically assess their patients' oxygen saturations and work of breathing. Oxygen saturation can be quantitatively monitored using pulse oximetry but work of breathing must be qualitatively monitored using visual exams or walking tests. The motivation of this research is to augment this qualitative assessment with a quantitative metric. In our research, we chose the volume of inhaled air (the "tidal volume") as a proxy metric for a patient's work of breathing. This thesis presents our attempt to use a nasal cannula augmented with pressure sensors to estimate the tidal volume of a mannequin undergoing nasal cannula therapy. Our concept is that more intense inhalations/exhalations produce larger pressure swings at the tip of the nasal cannula. For this proof-of-concept study, a simplified nasal passage geometry was used. Pressure waveforms obtained from continuous measurement of the pressure at the tip of the cannula are used to estimate nasal flowrates, and these nasal flowrates are time-integrated to estimate tidal volumes. Computational fluid dynamics (CFD) simulations were used to predict how the cannula tip pressure changes as a function of nasal flowrates and cannula flowrates, then this relationship was tested using a matching empirical experiment. This matching empirical experiment showed that our technique of estimating tidal volumes was 85% accurate. This study showed that continuous pressure measurement at the tip of a nasal cannula produces enough information to estimate nasal flowrates and tidal volumes. No similar studies were found during the literature review, so an accuracy of 85% is promising for this stage. If this technique could be made more accurate and deployed in an unobtrusive way, the resulting nasal cannula device could be used to continuously, comfortably monitor patients' tidal volumes.

In order to improve our understanding of present and future coastal environmental change, we look into the past using sediment that accumulates in coastal environments. We have done this for two disparate systems: a back-barrier lagoon in southwestern Japan, and freshwater tidal marshes along the Hudson River, New York, USA. In Japan, we used a 2,500-year sediment record to investigate coastal flood risk from tsunamis and typhoons. This is a critical area of study to better understand the spatial and temporal variability of these hazards in Japan. In the Hudson River we looked at modern (since 1800) deposition of sediment in anthropogenically constructed embayments that have formed tidal wetlands in the last few centuries. A better understanding of the factors that have attributed to these successful tidal marsh systems in the past can help inform future management decisions in the face of future sea level rise. Studying the history of coastal systems using the sediment record is a valuable tool for assessing hazard risk and habitat loss in the present and future.

Tidal variations of gravity were measured at fourteen sites in southeastern North America for periods of between 40 and 199 days. These measurements were used to obtain tidal gravity anomalies that indicate the geologic effect of the earth on tidal gravity. The tidal gravity anomaly is a vector quantity representing the difference between measured tidal gravity and the theoretical tidal gravity on a spherically symmetrical earth model subject to ocean tidal loading. The real part of the anomaly vectors include 8 values in the range of ±0.5 microgals, 4 values in the range of 0.5 to 1.5 microgals, 1 value of 1.5 to 2.5 microgals, and 1 other value in the range of -0.5 to -1.5 microgals, This grouping is consistent with a worldwide distribution of values from regions where the asthenosphere is at intermediate depth, the stress conditions are not excessive, and geothermal heat flow is approximately 60 mW/m². / Master of Science

Yes / This study presents results from laboratory experiments to investigate the wake structure in the lee side of a scaled three-bladed horizontal axis tidal stream turbine with a mono-pile support structure. Experiments are conducted for a range of approaching flow velocity and installation height of rotor. Analysis of the results shows that bed shear stress increases with the increase of approaching velocity and decrease of installation height within 2D (D is the diameter of the rotor) downstream of the rotor. The flow field within 2D downstream of the rotor is greatly influenced by the presence of nacelle and mono-pile. Low stream-wise flow velocity and large turbulence intensity level is detected along the flume center right behind the nacelle and mono-pile from 1D to 2D downstream of the rotor. Stream-wise velocity at the blade tip height lower than the nacelle increases sharply from 1D to 2D and gradually grows afterwards. Correspondingly, the turbulence intensity decreases quickly from 1D to 2D and slowly afterwards. Large bed shear stress is measured from 1D to 2D, which is closely related to turbulence induced by the mono-pile. It is also found that the presence of the mono-pile might make the flow field more ‘disc-shaped’. / National Key Research and Development Program of China (No.2017YFC1404200), the Marine Renewable Energy Research Project of State Oceanic Administration (No.GHME2015GC01), the Fundamental Research Funds for the Central Universities of China (No.2017B696X14) and the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (No.KYCX17_0448)

No / Horizontal-axis tidal turbines (HATTs) have the acknowledged potential to extract a large amount of green renewable energy from ocean tides. Among these, bidirectional HATTs (BHATTs) with centrosymmetric hydrofoils have advantages in terms of reliability and maintenance cost. To improve the performance of BHATTs, this paper investigates the influence of different passive flow control devices (PFCDs), such as wing fences, winglets, and squealers, on the performance of the BHATT. To the end, a three-dimensional (3D) numerical model with a k-ω SST model and a sliding mesh method was applied to simulate a 18 m diameter BHATT. The numerical framework was validated using two experiments. The mesh convergence was tested. The results show that the wing fences can effectively suppress the spanwise flow above the suction surface of blades, although they cannot improve the BHATT performance. To inhibit the wingtip vortices and enhance the torque of the rotor, a series of centrosymmetric winglets are designed and optimized. The optimal BHATT can produce up to 2.3% more energy at design tip speed ratio (TSR).