Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"Short-term variability"”.
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Drivers of short-term variability in phytoplankton production in an embayment of the southern Benguela upwelling system: an observational and modelling study
… difficult to predict given the high sub-seasonal variability that characterises this region. To better understand this variability, net primary production (NPP), nitrate and ammonium uptake, and phytoplankton community composition were measured for ten days during the upwelling season at an anchor …
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High-frequency sensor data capture short-term variability in Fe and Mn cycling due to hypolimnetic oxygenation and seasonal dynamics in a drinking water reservoir
… redox conditions in the hypolimnion. However, short-term (i.e., sub-weekly) trends in Fe and Mn cycling are less well-understood, as most monitoring efforts focus on longer-term (i.e., monthly to yearly) time scales. The potential for elevated Fe and Mn to degrade water quality and impact …
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Optical variability of radio-luminous palomar-green quasars
… is to test the shocked jet model for quasar variability at optical wavelengths. The ten quasars with the highest radio core luminosity at 5 GHz in the Palomar Bright Quasar Survey were selected for this monitoring program; Seven out of the ten radio-luminous quasars exhibited signs of …
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Variability within the 10-year pollen rain of a seasonal neotropical forest
… effect of seasonal and multiannual environmental variability on the abundance and composition of Neotropical pollen rain was investigated using ten years of seasonal aerial pollen samples from Barro Colorado Island (BCI), Panama. Using canonical correspondence analysis, we identified the …
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An Investigation of the Optimal Sample Size, Relationship between Existing Tests and Performance, and New Recommended Specifications for Flexible Base Courses in Texas
… sizes and testing frequencies based on material variability. A literature review yielded information on base course variability within and outside the state of Texas, and on what tests other states, and Canada, are currently using to characterize flexible base performance. A sampling and testing …
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Statistically Evaluating Water Consumption Historically and Across Multiple Users in Virginia
… rainfall distribution, indicating intraseasonal variability may play an important role in water use trends that is not apparent using seasonal averages alone. Overall, this work contributes to the understanding of water use trends at the state level for Virginia, and better characterizes …
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Spatial Temporal Analysis Using Hierarchical Bayesian Approach: Effects of Climate Variability on Primary Production of Deciduous Forests of the Northeastern U.S.
… Bayesian models to account for climate variability (anomalies) and short-term weather events (such as drought, heat) to quantify the effects of climatic variability on forest ecosystem productivity. I also explored different lagged effects of climate variability on GPP and found that GPP …
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Primary Productivity Distributions Along the River-Dominated Shoreline of the Bay of St. Louis, MS Estuary
… were taken to observe the temporal (monthly and short-term) and spatial variability in production relative to environmental variables that potentially could influence phytoplankton photosynthesis. Daily areal primary production, PP was modeled using photosynthesis-irradiance (P-E) parameters in …
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Controls on Dissolution Rate Variation at a Pair of Underflow-Overflow Springs at The Savoy Experimental Watershed
… and also do not aid our understanding of short term variability. This study characterizes natural variability in these rates and examines potential causes of that variability from first principles. This may enable more accurate projections of dissolution rates within models. This study …
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Tidally Induced Transport Dynamics in a Wadden Sea Tidal Basin and Its Changes Under Future Sea Level Rise Scenarios
… functioning, and the interpretation of long-term observations. However, the persistence of these structures under future sea level rise and changing wind conditions remains uncertain. This dissertation investigates the organisation of tidally induced transport in the Sylt-Rømø Bight, a …
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Low-head hydropower as a reserve power source for wind power
Wind power generation faces intermittency challenges, typically requiring reserve power generation sources burning fossil fuels to maintain reliability of the electricity grid in the event of a decrease in wind. This study proposes an alternative hypothesis: that hydropower turbines installed at …
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Evaluation of Coupled Erosional Processes and Landscape Evolution in the Teton Range, Wyoming
… conditions, therefore spatial and temporal variability can be high when observed over short time scales. This work evaluated methods for dissecting the history of complex alpine landscapes to understand the role of individual processes influenced by changing climate and underlying bedrock. …
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Essays on investment planning in electricity generating capacity
… of input prices. The first model highlights the shortcomings in assuming a constant plant utilization under uncertainty of input prices and the effects of such assumption on the optimal investment in electricity generating capacity in a simple two period model. The second model presents …
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Factors Affecting Short-term Oxygen Variability in the Northern Gulf of Mexico Hypoxic Zone
… an excellent opportunity to characterize short-term oxygen variability and to estimate the relative importance of key physical and biological factors controlling the development, persistence, and dissipation of hypoxia. I investigated temporal trends in three aspects of short-term DO …
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Scale-up and Measurement Enhancements of a BioGenerator Bioreactor
… abundance of these technologies that demonstrate short-term variability in power output threatens power grid stability and necessitates the use of fossil fuels for rapid throttling capability. A requirement for large scale energy storage systems becomes necessary and a system based on hydrogen …
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High-Latitude Southern Hemisphere Climate Variability, Trends, and Tropical Forcing.
… several inter-related aspects of climate variability in the Southern Hemisphere (SH) high-latitudes, with a focus on the time-varying behaviour and long-term trends in Antarctic sea ice and atmospheric circulation, as diagnosed from observations, reanalyses, and simulations using an …
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Impacts of Hard Stabilization on the Shore of Yellowstone Lake, Yellowstone National Park, Wyoming, USA
… improvement projects in an effort to determine the overall impacts of these projects on park environments relative to their benefits to park visitors and employees. The purpose of this study then was to contribute to this ongoing discussion of adverse impacts from shore armor by …
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Unveiling the X-ray Source Population of the Barred Spiral Galaxy NGC 2336
… revealed six hard sources, including two ULXs. Variability analysis using χ2 statistics identified 13 variable sources over the 7-month period. Eight sources varied in Period 1 (December 2020), and nine in Period 2 (July 2021), while all five ULXs showing long-term variability and two exhibiting …
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Marine weather variability, tropical cyclone prediction and impacts in the Southwest Indian Ocean
… by significant inter-annual climate variability and numerous tropical cyclones. Long-and short-term variability and associated oceanic and atmospheric fields are analyzed using model-assimilated data. The evolution of monsoon circulations associated with composite tropical cyclones …
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