As variações de temperatura influenciam nas propriedades da água, especialmente na viscosidade. Este pode ser um fator significativo, que afeta a vazão dos emissores e consequentemente a uniformidade de aplicação. A necessidade de estudos que considerem o material das fitas gotejadoras, com diferentes tipos de emissores integrados e diferentes características construtivas, são importantes para entender a sensibilidade desses materiais quando submetidos a temperaturas de água distintas. Este experimento foi conduzido no Laboratório de Ensaios de Material de Irrigação (LEMI) do Departamento de Engenharia de Biossistemas da Escola Superior de Agricultura \"Luiz de Queiroz\" - ESALQ/USP. Foram avaliados cinco tipos de fitas gotejadoras, com diferentes emissores integrados e espessuras de parede. As curvas vazão-pressão para os diferentes materiais e espessuras de parede, apresentaram a mesma tendência, porém, com valores distintos dos parâmetros K e x para cada temperatura. Os valores de CVf para todos os materiais nas diferentes temperaturas apresentaram valores em conformidade com o estipulado por norma técnica. Não houve uma tendência específica dos valores de CVf e de IQR em relação à temperatura da água para os materiais avaliados. Para os emissores planos de fluxo turbulento, a vazão tende a diminuir com o incremento da temperatura, porém não significativamente (p>0,05). Para os emissores contínuos de fluxo turbulento, respostas diferentes foram obtidas, sendo que no emissor SilverDrip&#174; a vazão aumentou com o incremento da temperatura (p<0,05), enquanto no emissor Turbo Tape&#174;, a vazão diminuiu e as maiores variações de vazão ocorreram a partir de 60 kPa (p<0,05). Para o emissor moldado, a vazão aumentou (p<0,05) em função da temperatura, porém a maior variação ocorreu nas pressões mais baixas. Para nenhum dos materiais houve diferença significativa (p>0,05) na variação de vazão entre as espessuras de parede, indicando para os emissores estudados, que a espessura de parede não influencia na sensibilidade do emissor às variações de temperatura. Os resultados obtidos indicam que a sensibilidade do emissor em função da temperatura da água está associada ao valor do expoente de fluxo do emissor. / Temperature variations influence the properties of water, especially viscosity. This can be a significant factor, which affects the emitters\' discharge and consequently the uniformity of application. Studies analyzing drip tape material, types of integrated emitters and manufacturing characteristics are important to understand the sensitivity of these materials when operated in a range of values of water temperature. This experiment was carry out at the Laboratory of Tests of Irrigation Material (LEMI) of the Department of Engineering of Biosystems of the \"Luiz de Queiroz\" School of Agriculture - ESALQ / USP. Five types of drip tapes were evaluated, with various integrated emitters and wall thicknesses. The pressure-flow curves presented the same trend for the evaluated material, however, different values of the parameters K and x were found for each temperature. The CVf for all materials evaluating in a range of temperatures presented values in accordance with technical standards. There was no specific trend of the values of CVf neither IQR in relation to the water temperature. For the turbulent flow emitters, the discharge tends to decrease with increasing temperature, but not significantly (p>0.05). For the continuous emitters of turbulent flow, different responses were obtained, the emitter SilverDrip&#174; the discharge increased with the increase of the temperature (p<0,05), while for the emitter Turbo Tape&#174;, the discharge decreased and the greater variations of flow occurred from 60 kPa (p<0.05). For the emitter molded, the discharge increased (p<0.05) as a function of temperature, but the greater variation occurred in the lower pressures. For any of the materials, there was a significant difference (p>0.05) in the discharge variation comparing the wall thicknesses, indicating for the emitters studied, the wall thickness does not influence the discharge sensitivity to temperature variations. The results indicate that the sensitivity of the emitter as a function of the water temperature is associated with the exponent of emitter flow.

In the agricultural state of Iowa, water quality research is of great importance for monitoring and managing the health of aquatic systems. Among many water quality parameters, water temperature is a critical variable that governs the rates of chemical and biological processes which affect river health. The main objective of this thesis is to develop a real-time high resolution predictive stream temperature model for the entire state of Iowa. A statistical model based solely on the water-air temperature relationship was developed using logistic regression approach. With hourly High Resolution Rapid Refresh (HRRR) air temperature estimations, the implemented stream temperature model produces current state-wide estimations. The results are updated hourly in real-time and presented on a web-based visualization platform: the Iowa Water Quality Information System, Beta version (IWQIS Beta). Streams of 4th order and up are color-coded according to the estimated temperatures. Hourly forecasts for lead time of up to 18 hours are also available. A model was developed separately for spring (March to May), summer (June to August), and autumn (September to November) seasons. 2016 model estimation results generate less than 3 °C average RMSE for the three seasons, with a summer season RMSE of below 2 °C. The model is transferrable to basins of different catchment sizes within the state of Iowa and requires hourly air temperature as the only input variable. The product will assist Iowa water quality research and provide information to support public management decisions.

CE-QUAL-W2 is a 2-D hydrodynamic and water quality model that has been applied to reservoirs, lakes, river systems, and estuaries throughout the world. However, when this model is applied for shallow systems, this model requires a long calculation time to maintain numerical stability, compared to applications of reservoirs or deeper river systems. To solve this problem, a new hydrodynamic and temperature model was built based on the framework of CE-QUAL-W2 but that allows for steady-state hydrodynamic computations. By calculating the hydrodynamics at steady-state, the time step for stability is relaxed and simulations can proceed at much higher time steps. The rest of the model framework is still used for water quality state variables, in this case, temperature. The algorithm used for computing the water surface elevation is Manning's equation. This thesis study is one part of the Willamette Water 2100 project (Santelmann et al., 2012), which examines hydrological, ecological, and human factors affecting water scarcity in the Willamette River Basin. This study included three stages: (1) Convert six existing CE-QUAL-W2 V3.1 models into a newer version: CE-QUAL-W2 V3.7. (2) Develop the steady-state model code in FORTRAN. (3) Test the steady-state model on three river systems in the Willamette River Basin at Year 2001 and 2002. The result proved that the steady-state model could reduce the computing time by 90% for river applications, while predicting dynamic river temperature with high accuracy at a two-minute time scale. This new model will be employed to simulate the future of the Willamette River System at a decadal or centennial timescales, addressing river temperature concerns and fish habitat issues.

Stratification of water in large reservoirs occurs in summer, or at anytime in hot climates where the water surface is exposed long-term to sunlight and the water surface is heated. Natural mixing will not occur due to the cooler and denser water always staying at the lower levels. Therefore, mechanical circulators are designed to prevent water quality problems related to stratification and depletion of dissolved oxygen. Impellers that produce the flow in mechanical circulators are available in different sizes and these impellers are designed to produce different flow rates. Due to hydraulic loadings, impellers have to be strong and durable. Loadings on impellers depend on their geometries and therefore, a durable impeller is a good combination of the use of correct materials and good geometry. Long and slender impellers are prone to failure when subjected to high hydrodynamic loadings. Nowadays, designers have very limited information on predicting the stresses on impellers and the deflection patterns of impellers because there are no design rules in designing these impeller blades and there is no such thing as "best geometry". A good impeller blade design is by guesswork and experience. In order to design the geometry that suits this application, trial-and-error finite element analyses have been conducted in this project to minimize stress levels on the blades. This research involves the use of finite element analysis (FEA) to predict stress and deflection of impeller blades used on large (5m diameter) ducted axial flow impellers as the first step in the design process. Then, based on the results, improvements have been done to the models until the final design was made. As far as the author has been able to determine, this has not been researched before. Finite Element Analysis has been used on wind turbine blades, rudders and hulls of boats but not on axial flow impeller blades of the type used in this project. For the purpose of this project, commercial finite element computer program packages STRAND6 and STRAND7 were used as the main analysis tools. A static line load increasing linearly with radius along the blade has been used to simulate the assumed hydrodynamic loading, and applied to all FEA blade models. The analysis results proved the stresses on blades are largely dependant on the blade geometry. From the analysis results, the author modified the stacking arrangement of the FEA elements in order to minimize both the tensile stresses and the displacements of the blades at the tip. Parametric studies have been done in order to obtain the best FEA impeller blade model.

Biological nutrient removal is used as an indicator of SBR performance at nine different SBRplants operated for a long period at low water temperatures (5 – 10oC). Typically needed aeratedSRT (Solids Residence Time) for complete nitrification is found to be in the range of 6 – 10 days.Biological phosphorus removal has been found to take place at 5oC. The specific nitrification and denitrification rates (g N/kg VSS/h) have been found to besubstantially higher than those found in design recommendations. At temperatures &lt; 10 oC thenitrification rates have been found up to 4 g Nox/kg VSS/h. It has also been possible to establish a relation between the COD/N ratio and the nitrificationrate, showing that the rate increases to high rates when the ratio decreases. Enhanced biological phosphorus removal has been demonstrated at two different plants even atlow water temperatures 5 – 7 oC. Efficient biological nitrogen removal and phosphorus removal has been demonstrated at bothlow water temperatures and in presence of very high Chromium concentrations in inlet water, upto 20 mg Cr/l. The plants operated with a short fill time in comparison with the total cycle time for the SBRprocess have all demonstrated good sludge settling properties, suggesting that the SBR processmay incorporate a good sludge selection performance. Once a flexible operation strategy has been installed (in most cases through PLC systems) it hasbeen possible to meet load variations to maintain good treatment results. This has been found tobe true for most of the plants included in the thesis. Finally, a modified way to assess the energy efficiency for the system is analysed and suggested.Instead of using the traditional ratio kWh/kg BODremoved the use of kWh/kg OCPremoved as a basisfor energy efficiency is used as a far more relevant efficiency measurement. / QC 20100803

Nannochloropsis oculata is one of promising oleaginous microalga, containing a plenty of fat which can be extracted and transformed into biodiesel. The purpose of this study is to develop a closed system, Outdoor Temperature Controllable Photobioreactor System (OTCPS), to cultivate the algae in pure and massive quantity. In this research, the seawater from Sizihwan is used as the cultivation liquid. Lambert-Beer¡¦s Law is adopted to calculate the attenuation coefficient of light intensity in a water column. By adjusting the water depth, not only the light intensity but also the water temperature could be controlled at the optimal situation and thus avoids unfavorable temperature changing in harsh weather. Therefore to establish the relationship of light intensity and water temperature is critical for the success of growing microalgae in outdoor conditions. The temperature variation of culture medium can be explained by the heat transfer theorem. In this study, the heat radiation mechanism and the first order of Fourier heat conductivity were adopted to simulate the liquid temperature change. The simulation results have shown good agreement with the filed data especially during daytime. The experimental results reveal that the winter grow rate of Nannochloroposis oculata is 0.33 d-1 , while the summer growth rate is only 0.20 d-1 . This may imply that the high temperature is an inhibition to the growth of Nannochloroposis oculata. Besides when the cell density of microalgae is getting higher, each individual alga may create mutual shading effect and thus reduce the photosynthetic efficiency. In conclusion, the proposed photobioreactor has been successfully tested in summer, autumn, and winter at Kaohsiung, in the south of Taiwan. This indicates that this device can be broadly used in the subtropic zone

Thesis (MS)--University of Montana, 2009. / Title from author supplied metadata. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 113-118). Also available on the World Wide Web.

Thesis (M.S.)--Springfield College, 2003. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--Springfield College, 2003. / Includes bibliographical references.