Current methods for measuring energy flow rate in a pipe use a variety of invasive sensors, including temperature sensors, turbine flow meters, and vortex shedding devices. These systems are costly to buy and install. A new approach that uses non-invasive sensors that are easy to install and less expensive has been developed. A thermal interrogation method using heat flux and temperature measurements is used. A transient thermal model, lumped capacitance method LCM, before and during activation of an external heater provides estimates of the fluid heat transfer coefficient ℎ and fluid temperature. The major components of the system are a thin-foil thermocouple, a heat flux sensor (PHFS), and a heater. To minimize the thermal contact resistance 𝑅" between the thermocouple thickness and the pipe surface, two thermocouples, welded and parallel, were tested together in the same set-up. Values of heat transfer coefficient ℎ, thermal contact resistance 𝑅", time constant 𝜏, and the water temperature °C, were determined by using a parameter estimation code which depends on the minimum root mean square 𝑅𝑀𝑆 error between the analytical and experimental sensor temperature values. The time for processing data to get the parameter estimation values is from three to four minutes. The experiments were done over a range of flow rates (1.5 gallon/minute to 14.5 gallon/minute). A correlation between the heat transfer coefficient ℎ and the flow rate 𝑄 was done for both the parallel and the welded thermocouples. Overall, the parallel thermocouple is better than the welded thermocouple. The parallel thermocouple gives small average thermal contact resistance 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑅"=0.00001 (𝑚2.°C/𝑊), and consistence values of water temperature and heat transfer coefficient ℎ, with good repeatability and sensitivity. Consequently, a non-invasive energy flow rate meter or (BTU) meter can be used to estimate the flow rate and the fluid temperature in real life. / MS / Today, the measuring energy flow rate, measuring flow rate and the fluid temperature, in a pipe is crucial in many engineering fields. In addition, there has been increased use of energy flow rate meters in the renewable energy system and other applications such as solar thermal and geothermal to estimate the useful thermal energy. Some of the commercial energy flow rate meters are using an invasive sensor, has to be inside the pipe, including turbine flow meter and vortex shedding device. These systems are expensive and difficult to install. A new approach that uses non-invasive sensors, attached on the outside of the pipe, that are easy to install and less expensive has been developed by using the heat flux and temperature measurements. A parameter estimation routine was used to analyze the data which depends on the minimum root mean square 𝑅𝑀𝑆 error between the calculated and experimental temperature values. A correlation between the unknown parameter, heat transfer coefficient (ℎ), and the measured flow rate 𝑄 was done to estimate the flow rate. The results show that the new non-invasive system has good repeatability, 15.45%, high sensitivity, and it is easy to install. Consequently, a non-invasive energy flow rate meter or (BTU) meter can be used to estimate the flow rate and the fluid temperature in real life.

Dissolved oxygen concentrations are declining in the bottom waters of many lakes around the world, posing critical water quality concerns. Throughout my dissertation, I assessed how bottom-water dissolved oxygen may mediate the effects of climate and land use change on water quality in lakes. First, I characterized causes of variation in summer bottom-water temperature and dissolved oxygen. I demonstrated that spring air temperatures may play a greater role than summer air temperatures in shaping summer bottom-water dynamics. I then characterized the effects of declining bottom-water oxygen concentrations across diverse scales of analysis (i.e., using microcosm incubations, whole-ecosystem oxygenation experiments, and data analysis of >600 widespread lakes). I found that low dissolved oxygen concentrations contributed to release of nutrients and organic carbon from lake sediments, potentially altering the role of lakes in global biogeochemical cycles. Importantly, I also found support for a previously-hypothesized Anoxia Begets Anoxia feedback, whereby bottom-water anoxia (i.e., no dissolved oxygen) in a given year promotes increasingly severe occurrences of anoxia in following summers. This finding demonstrates the need for forecasts of future oxygen dynamics in lakes, as management actions to preempt the first occurrence of anoxia will be more effective than actions to restore ecological function after oxygen concentrations have already declined. To build the capacity for such forecasts, I led a systematic review of ecological forecasting literature that characterized the state of the field, emerging best practices, and relative predictability of four ecological variables. Combined, my dissertation provides a mechanistic examination of the effects of climate change on water quality in lakes worldwide, ultimately helping to anticipate, mitigate, and preempt future water quality declines. / Doctor of Philosophy / Changes in climate and land use have caused dissolved oxygen concentrations to decline in many lakes around the world. These declines are concerning because low oxygen concentrations can cause substantial water quality problems. If we could better predict future water quality, we may be able to develop more effective lake management programs. To help meet this need, I analyzed how dissolved oxygen has mediated historical changes in water quality, and how dissolved oxygen may affect water quality in the future. I focused on bottom-water (rather than surface-water) dissolved oxygen, because bottom waters are more likely to experience very low oxygen concentrations that can lead to water quality problems. I started by assessing the drivers of summer bottom-water dissolved oxygen in 615 lakes. Across these lakes, spring air temperatures played a greater role than summer air temperatures in shaping summer bottom-water temperature and dissolved oxygen. I then characterized the effects of declining bottom-water oxygen concentrations using small-scale incubations in the lab, manipulations of oxygen concentrations in a whole reservoir, and data analysis across 656 lakes. I found that low dissolved oxygen conditions led to the release of nutrients and organic carbon from lake sediments, which may worsen water quality. Importantly, I also found support for a feedback effect, whereby low bottom-water dissolved oxygen in one summer perpetuates oxygen declines in following summers. This finding motivates the need for forecasts of future dissolved oxygen concentrations, as management actions to stop the first occurrence of low oxygen concentrations will be more effective than actions to restore water quality after oxygen concentrations have already started to decline. To build capacity for lake oxygen forecasts, I synthesized many published papers that have predicted future ecological states, and I documented proposed best practices in this emerging field. Ultimately, by advancing our understanding of how climate and land use change affect water quality in lakes worldwide, my dissertation research will help to anticipate, mitigate, and preempt future water quality declines.

Understanding water temperature dynamics in lakes is essential for ecological and environmental management. This study focuses on Lake Erken, Sweden, aiming to develop and validate a three-dimensional (3D) hydrodynamic model using the MIKE 3 FM modelling system to simulate the lake's water temperature distribution. The model performance was evaluated by comparing simulated water temperature profiles with observed data at various depths, distinguishing between the upper layer and deeper layers. Results showed satisfactory performance, with the model capturing seasonal and spatial variations in the lake’s thermal structure. The root-mean-square error (RMSE) for water temperature simulation ranged between 0.7-1.8°C, and the Nash-Sutcliffe efficiency (NSE) was between 0.86-0.99 across different depths. However, the model has limitations in accurately capturing stratification in deeper layers, especially during the summer months. This research underscores the importance of accurate temperature modelling for understanding lake ecosystems and provides insights for future improvements in hydrodynamic simulations.

Hot water discharges and potential chemical spills are factors that threaten water quality in cooling reservoirs of chemical and power plants. In this thesis, three models are used to analyze the impact of these factors in a particular case study.

Cette recherche évalue le degré de régulation hydrologique induite par le barrage-réservoir Paso de las Piedras sur la Sauce Grande et quantifie les effets de cette régulation sur la hydrologie, la morphologie et la température de l'eau de la rivière en aval. Le travail de thèse consiste en une évaluation exhaustive et systématique des impacts du barrage-réservoir sur le système fluvial basée sur la compréhension des processus naturels qui se produisent en amont. En plus de fournir des informations sur les impacts hydrologiques, morphologiques et thermiques de la construction du barrage Paso de las Piedras et de l'exploitation de son réservoir, cette étude génère des séries de données climatiques et hydrologiques qui fournissent une base significative sur laquelle fonder des recherches futures. Par ailleurs, cette étude met en place un cadre méthodologique appliqué à l'analyse hydrogéomorphologique des bassins versants non jaugés qui a un grand potentiel d'application dans d'autres bassins de la région similaires ainsi que dans d'autres régions semi-arides du monde. / Despite the regional importance of the Sauce Grande River as main source for water supply and the large capacity of the Paso de las Piedras Reservoir, both the hydrology of the river basin and the effects of the impoundment on the river environment remain poorly evaluated. This study provides the very first assessment of the degree of flow regulation induced by the Paso de las Piedras Dam on the middle section of the Sauce Grande River, and quantifies its impacts on the hydrology, morphology and patterns of water temperature of the river downstream from the impoundment. In addition to providing new information on the response of regulated rivers to upstream impoundment and on the effects of impoundment on the Sauce Grande River specifically, this study generates spatial, climatic and hydrologic data and implements a methodological framework to hydrological assessment of ungauged basins.

Reproductive containment in farmed fish is highly desired for sustainable aquaculture to prevent genetic introgression with wild conspecifics and enhance productivity by suppressing sexual maturation. A number of strategies have already been implemented or have been tested in commercially important fish (e.g. triploidy, monosexing, hormonal therapies); however, they either do not result in 100% containment, or they cannot be applied to all species. One promising new approach consists in disrupting primordial germ cells (PGCs), at the origin of germline cells, to induce sterility. The work carried out in this doctoral thesis aimed to investigate the genes involved in the survival of germ cells and subsequently conduct a functional analysis of candidate genes using CRISPR/Cas9 gene editing system to ultimately provide the basis for the development of a novel sterilisation technique. Nile tilapia was chosen as the experimental animal as it is a major aquaculture species worldwide and the control of reproduction plays a critical role in the farming productivity in this species. In addition, the species has clear advantages as its whole genome sequence is accessible, the generation time is relatively short and zygotes can be available all year round. Initially, a panel of 11 candidate genes with reported roles in survival of PGCs was investigated during the ontogenic development which led to the selection of piwi-like (piwil) gene as a target for genome editing. Then, high temperature was tested as a means to induce germ cell loss to better understand the mechanism underlying germ cell survival and apoptosis, and this study confirmed the functional importance of piwil genes in relation to germ cell loss and proliferation. In addition, the study suggested potential subfunctionalisation within the Bcl-2 gene family which requires further investigation. The next step aimed to optimise the CRISPR/Cas9 gene editing method by improving the microinjection system and testing different concentrations of sgRNAs. Over 95% of injected embryos showed on-target mutation in piwil2 via zygote injection of CRISPR/Cas9 reagents and complete KO larvae were shown in half of the mutants, producing putative sterile fish. However, there was no clear association between the phenotypes in PGCs and the mutation rate. Further comparative studies of mutant screening methods including T7E1, RGEN, HRMA, fragment analysis and NGS revealed that the genotypes of F0 are highly mosaic, suggesting that deep sequencing is recommended for accurate and high throughput F0 screening and further improvement for predictable genome editing is required for a reliable gene functional analysis in F0. In summary, the current thesis provided new scientific knowledge and supporting evidence for the use of the CRISPR/Cas9 gene editing platform to study gene function associated with sterility, with the ultimate goal to develop an alternative sterilisation method in fish.

Spray cooling of hot surfaces is used in the metallurgical industry during continuous casting, hot rolling or heat treatment. The water is sprayed on the cooled surface by the nozzle which transforms the water stream to droplets. The spray cooling of hot surfaces can be characterized as forced convection with the presence of the boiling. This physically complicated process is influenced by many factors, such as impurities and contaminants in the water, water temperature, water flow rate, droplet size, droplet impact velocity, surface temperature, surface roughness or the presence of oxides (scales) on the cooled surface. The dominant factor that affects the heat transfer during the spray cooling is the water impingement density. Other factors have a smaller but also significant effect. This doctoral thesis deals with the influence of the water temperature, surface roughness and the presence of oxides on the intensity of the spray cooling. These factors are investigated by laboratory experiments in which the hot steel surface is spray cooled. Effect of the oxide layer is also investigated by the numerical simulation. The experimental results are theoretically explained and generalized using mathematical methods.

This master thesis focuses on an analysis of surface water chemistry, long-term trends and the impact of drought on changes in concentrations of selected parameters in the upper Svatava, Rolava and Načetínský potok basins located in the Ore Mountains. Research on water quality in mountain spring areas is important, the consequences of various changes can be easily observed there. This work analyses the changes in surface water chemistry and discusses their possible causes, especially the impact of peat bogs and dry episodes. The parameters of water temperature, conductivity, pH, BOD5, COD, TOC, concentration of nitrate nitrogen, total phosphorus, phosphates, sodium, potassium, calcium and iron were investigated for the period 1993-2018. The available data are analysed using evaluation methods according to ČSN 75 7221 as well as box plots, Pearson correlation coefficient, PCA analysis and Mann-Kendall test. The greatest anthropogenic influence exhibited in Svatava, almost all concentrations reached their highest values there. In the Rolava and Načetínský potok basins, the influence of peatlands manifested itself by increasing the concentrations of iron, TOC and COD. The results of trends showed an increase both in pH and in surface water temperature related to an increase in air temperature, on the...

Uppsala Municipality has, through previous projects, tried to communicate information about public bathing sites on a map by having employees manually look up temperature readings before posting them on Facebook. The projects have shown to be an inefficient use of resources. Therefore, a user-friendly website has been built to visualise relevant information on 21 public bathing sites in Uppsala Municipality. By having access to temperatures in the water and air at bathing sites on the website, citizens, and tourists can make a more informed decision on which public bathing site they should travel to. Conducted user tests for the website show that 71.6% would use it before visiting a bathing site, and further, 20.6%, may use it. To supply the website with data, we developed an API, specifically a public data API. / Uppsala Kommun har genom tidigare projekt försökt att förmedla information om offentliga badplatser på en karta med hjälp av anställda som manuellt läser av värden för att sedan publicera dessa på Facebook. Detta har visat sig vara en ineffektiv användning av resurser. Därför har en webbsida byggts som visualiserar relevant information om 21 offentliga badplatser i Uppsala Kommun på ett användarvänligt sätt. Med webbsidan kan medborgare eller turister ta ett mer informerat beslut och semestra inom kommunen genom att ha tillgång till temperaturen i vattnet och luften vid badplatser. Utförda användartester visar att 71.6% kan tänka sig använda webbsidan, och 20.6% kan kanske tänka sig använda webbsidan inför ett badbesök. För att tillhandahålla information till webbsidan har en API utvecklats, specifikt ett öppna data API.

Bakterien Legionella pneumophila orsakar sjukdomen Legionella vilket har ökat i världen de senaste 20 åren och har troligtvis ett ännu större mörkertal. Den frodas i vattenrör mellan temperaturen 25–50 grader och vid installation av varmvattenrör i byggnader måste det tas hänsyn i riskzoner. Ett speciellt riskområde är varmvattenavstick som skapas för att kunna dra vidare vattenrör i framtiden. Där utsätts vattnet för större risk för stillastående och sjunkande temperaturprofil beroende på längd. Med hjälp av COMSOL Multiphysics® Modelling Software har ett teoretiskt ramverk för dimensionering av varmvattenavstick i byggnader skapats. Resultatet visar på hur stor strömningshastighet i vattenflödet, isoleringstjocklek och luftrörslängd har påverkan på hur långt avsticket kan vara utan att understiga kritisk temperatur. Resultatet kan användas som beslutsstöd givet att liknande avstickmodell och flödesprofil används samt om strömningshastighet i röret inte är längre än det i rapporten. / The bacterium Legionella pneumophila causes the disease Legionella which has seen an increase in the world over the last 20 years and likely has an even greater number of unrecorded cases. It thrives in water pipes between the temperature of 25-50 degrees and when installing hot water pipes in buildings certain factors must be taken into account. A special risk area is hot water branches that are created to be able to extend water pipes in the future. There, the water is at greater risk of stagnant and decreasing temperature profile depending on its length. With the help of COMSOL Multiphysics® Modelling Software, a theoretical framework for the dimensioning of hot water distances in buildings has been created. The result shows how the velocity in the water flow, the insulation thickness and the length of the air pipe have a great influence on how long the branch can be without falling below the critical temperature. The results can be used as decision support if one has a similar branch model and flow profile and also given a that a lower flow rate is not used.