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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 19 of 19 for “"water age"”.
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Identifying nitrate transport mechanisms and export dynamics using water age modeling and concentration-discharge relationships
… source of nitrate (NO3-) loss to surface waters. Water flow paths and residence times determine the contact length between NO3- and sub-surface material, controlling the rate of biogeochemical reactions and nitrogen removal via denitrification. A Nitratax N- NO3- sensor was installed at …
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Impact of Flow Rate and Water Age on Opportunistic Pathogen Growth: Implications for Water Conservation, Fixture Design, and Policy
Water conservation efforts have led to a decrease of flow rates in buildings, increasing water retention time (WRT) and sometimes opportunistic pathogens (OPs) growth. A novel experiment with replicated distal pipes operated at commonly used flow rates was designed to evaluate the effects of water …
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Lead and Copper Contamination in Potable Water: Impacts of Redox Gradients, Water Age, Water Main Pipe Materials and Temperature
Potable water can become contaminated with lead and copper due to the corrosion of pipes, faucets, and fixtures. The US Environmental Protection Agency Lead and Copper Rule (LCR) is intended to target sampling at high-risk sites to help protect public health by minimizing lead and copper levels in …
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Hydrodynamics of a coral atoll lagoon and its connection to large-scale climate variability
… of large-scale climate variability, and water dispersal timescales in the semi-enclosed lagoon of Kanton Island, Republic of Kiribati, using a high-resolution three-dimensional numerical model. The baseline hydrodynamic variability is characterized across tidal to seasonal timescales, …
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Impact of emerging water scenarios on performance of urban water networks
… have prompted the development and adoption of water-demand management strategies. Water and energy savings from increasingly efficient technologies, diversified water sources, and water savings policies are typically quantified from an individual demand-side basis, but network-wide potential is …
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Critical factors controlling regrowth of opportunistic pathogens in premise plumbing
… Pseudomonas aeruginosa) residing in human-made water systems, particularly premise plumbing, are now the primary source of water-borne disease in developed countries. The prevention and control of opportunistic pathogens is a new challenge in premise plumbing due to the limited knowledge …
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IMPACT ASSESSMENT OF URBAN DECLINE ON COUPLED HUMAN AND WATER SECTOR INFRASTRUCTURE SYSTEMS
… of urban decline on the coupled human and water sector infrastructures. Aspects such as the drivers of population decline and transitioning to a smaller city for the current and projected populations in shrinking cities have been well-studied by political and social scientists. However, the …
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Unveiling Causal Links, Temporal Patterns, and System-Level Dynamics of Freshwater Salinization Using Transit Time Distribution Theory
Inland freshwater salinity is rising worldwide and threatens the quality of our water resources, a phenomenon called the freshwater salinization syndrome (FSS). Simultaneously, the practice of indirect potable reuse (IPR) that augments critical water supplies with treated wastewater to enhance …
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Evaluating Coliform Monitoring Strategies for Contamination Scenarios in a Distribution System Model
Large public water utilities currently are required to take several 100 mL water samples every month in their distribution systems and to test these samples for the presence of total coliforms to comply with the Total Coliform Rule. How and where they take these samples is not specified. The Total …
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Designing Smarter Stormwater Systems at Multiple Scales with Transit Time Distribution Theory and Real-Time Control
Urban stormwater runoff is both an environmental threat and a valuable water resource. This dissertation explores the use of two stormwater management strategies, namely green stormwater infrastructure and stormwater real-time control (RTC), for capturing and treating urban stormwater runoff. …
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Incorporating Recent Geochemical and Isotopic Constraints in Age Dating the Waters of Hot Springs National Park, Arkansas
<p>Mean water age for spring discharge in Hot Springs National Park was calculated as approximately 4,400 years by Bedinger et al (1978) using carbon-14. Their analysis indicated that the water was a mixture of a small portion of cold water that was less than twenty years old with a preponderance …
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Multivariate Analysis of Disinfection By-products Formation in Drinking Water Distribution Systems
Drinking water distribution systems (DWDSs) have historically been looked upon like a black box, in which various chemical and microbial processes affect disinfectant residuals stability. This results in disinfectant residuals decay and unintended disinfection by-product (DBP) formations, which are …
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Growth of Opportunistic Pathogens in Domestic Plumbing: Building Standards, System Operation, and Design
… to opportunistic pathogens (OPs) in domestic water (i.e., hot/cold water for human use) will be one of the grand challenges for water safety in the 21st century. This dissertation anticipates some of the complexities in balancing stakeholder goals and developing building standards to limit OP …
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Organic Carbon Generation Mechanisms in Main and Premise Distribution Systems
… AOC was compared in controlled simulated water heater experiments. Under the worst-case condition, generation up to 645 µg C/L was observed. IT was not possible to directly confirm the biodegradability of the generated organic carbon, and there were generally no correlations between …
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Head-dependent modelling and optimisation of water distribution systems
The construction, operation and maintenance of water distribution systems (WDSs) involve a huge capital investment and it is essential to design and manage them in a cost effective way. The optimisation approaches (e.g. evolutionary algorithms) for optimal design or operation of WDSs require …
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Evaluating and Improving Performance of Bisulfite Short Reads Alignment and the Identification of Differentially Methylated Sites
… tissues, cell types, and developmental stages. Accurate characterization of DNA methylation is essential for understanding genotype phenotype association, gene and environment interaction, diseases, and cancer. The thesis work first evaluates the performance of several commonly used …
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Characterization of opportunistic Pathogens in Drinking Water Supplied by Private Wells
… and are known to proliferate in drinking water systems. Much of our knowledge surrounding OP occurrence and growth in drinking water relates to municipal drinking water systems, which primarily use surface water sources and are always treated with primary and secondary disinfection in …
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Assessing the Potential of Granular Activated Carbon Filters to Limit Pathogen Growth in Drinking Water Plumbing Through Probiotic Versus Prebiotic Mechanisms
… pathogens that can be transmitted via drinking water, when tiny droplets containing the bacteria are aerosolized and inhaled during activities such as showering. The resulting respiratory illnesses, Legionnaires’ Disease and NTM lung disease, are among the leading sources of drinking water …
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Festlegung von Radionukliden und Arsen in Feuchtgebieten an Bergbaualtstandorten – Ein Beitrag zur Passiven Wasserreinigung
… Zentimetern des Sediments (organische Auflage) aus der wässrigen Phase und nicht von ca. 300 Millionen Jahre alten Erzteilchen stammt. Für die Verlagerung von Radionukliden und Arsen aus dem Wasserkörper in das Sediment wird ein neuer Weg aufgezeigt. Eine Fixierung dieser Stoffe an …