The flow characteristics of the subcritical and supercritical flows over a free overfall in a rectangular channel are studied experimentally. A series of experiments were conducted in a tilting flume with a wide range of flow rate. Data collected by several researchers are also included. An empirical relationship, which gives the flow rate as a function of the brink depth, the channel bed slope and the bed roughness are confirmed by using data collected in present study. In addition, the behaviors of the ratio of the brink depth to the critical depth according to several flow parameters are examined. Further, the location of the critical depth in subcritical flows while flow is approaching to the fall is investigated. It is concluded that the location of the critical depth in subcritical flow is a function of the Froude number, channel bed slope and the Manning roughness coefficient. The resemblance or the difference in the occurrence of the profile in sub and supercritical flows examined.

Water aerosols affect the climate because they have an impact on the radiation balance and cloud formation. Water is present in all forms in the atmosphere (water, ice and steam), for example as rain and hail. Water aerosols play an important role in many biological and chemical processes in the atmosphere. The most common form of water in the atmosphere is water droplets or vapor which often come from oceans and lakes and these aerosols often contain organic compounds. It is therefore interesting to study if organic compounds, in this case glycerol, will reside on the surface or inside the water droplets. The investigations were performed by using theoretical studies, molecular dynamic simulations in GROMACS, and experimental investigations; X-ray photoelectron spectroscopy with a liquid jet. The experiments were performed at BESSY II, Berlin. The concentrations of glycerol were varied from 75:1; 8:1 to 4:1 (water: glycerol molecules). The results were that the experiments and simulations indicated that when theconcentration of glycerol increased the glycerol concentration at the surface of the waterdroplet increases until a monolayer of glycerol molecules was formed at the surface. When the monolayer was formed (or close to) less and less glycerol molecules were placed at thewater surface and more and more glycerol molecules were placed in the bulk of the waterdroplet. / Vattenaerosoler påverkar klimatet eftersom de har en inverkan på strålningsbalansen och molnbildningen. Vatten finns i alla former i atmosfären (vatten, is och ånga) som bland annat regn och hagel. Vatten aerosolerna spelar en viktig roll i många kemiska och biologiska processer i atmosfären. Den vanligaste formen av vatten i atmosfären är små vattendroppar eller ånga som ofta kommer från hav och sjöar och som ofta innehar organiska föreningar. Då vattenaerosoler påverkar klimatet och organiska föreningar är vanligt förekommande i vattendroppar är det intressant att undersöka om organiska föreningar, i detta fall glycerol, hamnar på ytan eller inuti vattnet. Undersökningarna har gjorts genom att använda teoretiska perspektiv, molekylärdynamiska simuleringar i GROMACS, samt experimentella undersökningar i form av röntgen fotoelektronspektroskopi med en vätskejet. Dessa experiment utfördes i BESSY II, Berlin. Koncentrationerna av glycerol varierades från75:1; 8:1 till 4:1 (vatten: glycerolmolekyler). Resultaten från experimenten och simuleringarna indikerade att när koncentrationen av glycerol ökade så ökade glycerolkoncentrationen på ytan av vattendroppen tills det bildades ett monolager av glycerolmolekyler på vattenytan. När monolagret hade bildats så placerades mindre och mindre glycerolmolekyler på vattenytan och fler och fler glycerolmolekyler placerades inne i vattendroppen.

Baigiamajame darbe pateikta: detergentų paplitimas, jų fizikinės, cheminės savybės, klasifikacija ir daroma žala aplinkai. Analizuojami detergentais užterštų nuotekų valymo metodai. Analizuojami dujų burbuliukų susidarymo detergentų tirpaluose ypatumai, aprašomos dinaminės ir statiškai stabilios putos, pateikiama putų aparatų charakteristika. Pateikiamos suspenduoto sluoksnio charakteristikos ir jo galimybės detergentams iš nuotekų valyti. Darbo tikslas – ištirti suspenduoto sluoksnio įtaką valant detergentus iš nuotekų. Darbą sudaro 7 dalys: įvadas; tyrimo objektas ir problemos aprašymas; detergentais užterštų nuotekų valymas, putų burbuliukų ir putų susidarymo ypatumai, putų aparatai; suspenduoto sluoksnio charakteristikos ir jo galimybės panaudojant detergentams iš nuotekų valyti; eksperimentinė dalis; išvados; literatūros sąrašas. Eksperimentinėje dalyje teoriškai apskaičiuoti suspenduoto sluoksnio parametrai, aprašomas eksperimentinis stendas, jo veikimo principas, naudotos matavimo priemonės, pateikta eksperimento atlikimo metodika, pagal gautus eksperimentinius duomenis apskaičiuoti kintamieji suspenduoto sluoksnio parametrai. Darbo pabaigoje analizuojami gauti rezultatai ir pateikiamos darbo išvados. Darbo apimtis – 67 p. teksto be priedų, 21 iliustracija, 4 lentelės, 24 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai. / Thesis submits the spread of detergents, their physical, chemical properties, classification and environmental damage. There are analyzed various waste water cleaning methods of detergents. Froth formation in detergent leaches, dynamic and static stability of foams and basic information about froth devices are given. The characteristics of the suspended layer and its use in water treatment of detergents are given. The aim of this work – is to explore the suspended layer in cleaning waste water of detergents. Final work consists of seven parts: introduction; the subject matter and the problem description; water purification of synthetic detergents, characteristics of froth bubbles and froth formation, froth machines; suspended layer characteristics and the possibility of using it in waste water cleaning of detergents; experimental part; conclusions and references. Experimental part includes theoretically calculated suspended layer parameters, description of the experimental stand, its operating principle, instruments used during the experimental procedures, calculations of suspended layer variable settings according to the experimental data. In the end the results are analyzed and the conclusions are included. Thesis consists of: 67 p. text without appendixes, 21 picture, 4 tables, 24 bibliographical entries. Appendixes included.

Ionization chambers (ICs) are the most commonly used detectors for radiation therapy dose measurements. Typical IC measurements use cylindrical ICs in a water phantom and therefore require initial IC alignment to the water surface. This alignment has long been ignored and only recently has a qualitative governing recommendation been made. This thesis describes a reproducible methodology for quantitative ionization chamber water surface alignment. Depth-ionization measurements are taken with twenty-eight IC designs under varying conditions including, but not limited to, changes in scan direction, speed, and resolution, radiation beam type, field size, energy, and electron contamination. Measurements are acquired using standard radiotherapy accelerators in the Virginia Commonwealth University Department of Radiation Oncology and at the National Research Council of Canada, where a customized scanning system capable of better than 0.15 mm IC positioning precision is used. Measurements are also performed with standard commercial scanning equipment on the Accuray CyberKnife, a specialized radiosurgery-class accelerator. An analytical model is developed from basic principles to test the theoretical foundations of IC response near a water surface. The theoretical foundation is further validated via Monte Carlo simulation models that fully account for all details of the ICs used to take measurements. It is determined that the dose gradient as a function of depth is maximized when a given IC reaches the water surface when moving from depth in water. This effect is unchanged under all of the measurement scenarios tested. Measurements taken at 0.1 mm resolution for several seconds per point over several millimeters near the surface will yield a gradient peak that can be used for quantitative alignment. Using developed software, multiple scans at variant resolutions can be stitched into typical clinical scans so as not to significantly affect clinical measurement workflow. The recommended measurement method is developed in a format suitable for inclusion into a clinical protocol for depth-ionization measurement acquisition.

A quantitative understanding of ground water flow characteristics in unconfined aquifers is important because of the prevalence of abstraction from, and pollution of these systems. The current understanding of ground water flow in unconfined aquifers is limited because of the dominance of horizontal flow modelling strategies used to represent unconfined flow processes. The application of horizontal flow principles leads to an ignorance of seepage-face formation and can not predict the complicated three-dimensional nature of the ground water flow that dominates at the ground water-surface water interface. This study aims to address some of these deficiencies by exploring the true three-dimensional nature of ground water flow including the formation of seepage faces at the ground water-surface water interface using numerical and laboratory techniques. A finite element model for simulating two-dimensional (vertical) variably saturated flow is developed and benchmarked against standard laboratory and field-scale solutions. The numerical features of the finite element model are explored and compared to a simple finite difference formulation. The comparison demonstrates how finite element formulations lead to a broader spatial averaging of material properties and a different method for the representation of specified flux boundaries. A detailed comparison analysis indicates that these differences in the finite element solution lead to an improved approximation to the partial differential equation governing two-dimensional (vertical) variably saturated flow. A laboratory analysis of unconfined ground water flow and associated solute transport characteristics was performed. The analysis focused upon unconfined flow towards a pumping well. The laboratory observations were reliably reproduced using a three-dimensional (axi-symmetric), variably saturated ground water flow model. The model was benchmarked against the ground water flow characteristics such as the seepage-face height and total flow rate. In addition, the model was shown to reliably reproduce the solute transport features such as travel times and streamline distributions. This is the first time that a numerical model has been used to reliably reproduce the solute transport characteristics near a seepage-face boundary where the three-dimensional flow effects are prevalent. The ability to reliably predict solute transport patterns in the seepage-face zone is important since this region is known to support vital microbially facilitated reactions that control nutrient cycling and contaminant attenuation. The three-dimensional travel time distribution near the seepage-face was compared to that predicted using a horizontal flow modelling approach derived from the basic Dupuit-Forchheimer equations. The Dupuit-Forchheimer based model indicated that horizontal flow modelling would under-estimate the total residence time near a seepage-face boundary, thereby introducing a considerable source of error in a solute transport analysis. For this analysis, a new analytical solution for the steady travel time distribution in an unconfined aquifer subject to a single pumping well was derived. The analytical model has identified, for the first time in the hydrogeology literature, the use of the imaginary error function. The imaginary error function is a standard transcendental function and an infinite series approach to evaluate the function was successfully proposed. The two-dimensional (vertical) ground water flow model was extended to handle the case where the flow is driven by density gradients near the ground water-surface water interface. The unsteady, two-dimensional, Galerkin finite element model of density-dependent ground water flow in variably saturated porous media is rigorously presented and partially benchmarked under fully saturated (confined) conditions. The partial benchmarking involved reproducing solutions to the standard Henry salt-water intrusion and the Elder salt-convection problems. The model was used in a standard density-coupled and a new density-uncoupled mode to elucidate the worthiness of the Henry and Elder problems as benchmark standards. A comparison of the coupled and uncoupled solutions indicates that the Henry salt-water intrusion problem has limited worthiness as a benchmark as the patterns of ground water flow are relatively insensitive to density-coupled effects. Alternatively, the Elder problem is completely dependent upon a correct representation of the density-coupled flow and solute transport processes. The coupled versus uncoupled comparison is proposed as a new test of the worthiness of benchmark standards. The Henry salt-water intrusion problem was further analysed in an attempt to alleviate some of the difficulties associated with this benchmark problem. The numerical model was tested against a re-evaluated version of Henry's semi-analytical solution for the coupled solute concentration distribution. The numerical model was used to propose a modified version of the Henry problem where the importance of density-coupled processes was increased. The modified problem was shown to have an improved worthiness as compared to the standard solution. The numerical model results were benchmarked against a new set of semi-analytical results for the modified problem. Certain advantages in using the modified problem as a test case for benchmarking the results of a numerical model of density-dependent ground water flow are identified. A numerical investigation of the patterns of density-driven ground water flow at the ground water-surface water interface was undertaken. The numerical model is shown to produce grid-independent results for a finely discretised domain. The pattern of discharge is controlled, in part, by two parameters. One describes the recharge applied to the aquifer, and the second describes the magnitude of the density differences between the fresh recharging fluid and the saline receiving fluid. The influence of dense intrusions upon the formation of seepage-face boundaries at the ground water-surface water interface under steady-state conditions was also investigated. Dense intrusions are shown to dominate the pattern of ground water flow only under mild recharge conditions, while seepage faces dominate the outflow pattern under strong recharge conditions. Therefore, the formation of seepage-face boundaries and dense intrusions are unlikely to coincide under the conditions examined in this study.

Submitted by Elóy Esteves Gasparin null (eloygasparin@gmail.com) on 2018-01-11T16:00:01Z No. of bitstreams: 1 Dissertação_Versão_Final_Elóy_Esteves_Gasparin.pdf: 1930199 bytes, checksum: 9e07c05152e38b9d557c7ac3cc3b6da7 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-01-11T18:38:30Z (GMT) No. of bitstreams: 1 gasparin_ee_me_ilha.pdf: 1930199 bytes, checksum: 9e07c05152e38b9d557c7ac3cc3b6da7 (MD5) / Made available in DSpace on 2018-01-11T18:38:30Z (GMT). No. of bitstreams: 1 gasparin_ee_me_ilha.pdf: 1930199 bytes, checksum: 9e07c05152e38b9d557c7ac3cc3b6da7 (MD5) Previous issue date: 2017-12-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Devido à alta demanda da substituição de fontes de energia que utilizam combustíveis fósseis por fontes de energia renovável, a ciência atual busca maximizar a eficiência das fontes renováveis para que sejam economicamente competitivas no mercado. Grande parte da liderança brasileira neste campo se deve à fonte hidráulica, que impacta negativamente o meio ambiente e as populações ribeirinhas. Assim, outras fontes renováveis como a eólica e a solar têm aumentado sua participação na matriz energética do país. Diante deste contexto, sistemas fotovoltaicos com alta eficiência podem aumentar a participação da energia solar na matriz interna de energia elétrica do Brasil. Os sistemas fotovoltaicos flutuantes são 11% mais eficientes do que os sistemas instalados em terra devido às menores temperaturas de operação. Para determinar se a umidade relativa do ar tem influência na eficiência das plantas flutuantes, neste trabalho, a partir de uma análise numérica, avaliou se a eficiência de conversão de energia é influenciada pela distância entre a superfície da água e o módulo fotovoltaico flutuante. Além disso, estudou dois tipos diferentes de módulos fotovoltaicos (monocristalinos e flexíveis) durante as quatro estações do ano, avaliando suas peculiaridades. A Planta Fotovoltaica de Rosana/SP foi utilizada como base para formulação dos modelos físicos, que resultaram em um modelo matemático solucionado através do Método de Volumes Finitos nos softwares FLUENT® e MECHANICAL® do pacote ANSYS®. As quatro distâncias simuladas (100, 300, 600 e 900mm) determinaram que os modelos físico e matemático adotados não captaram de forma conclusiva se as temperaturas de operação dos módulos diminuem com a aproximação da superfície da água. A potência gerada por um módulo monocristalino é 38,8% maior do que a gerada por um módulo flexível, no entanto os monocristalinos são dez vezes mais sensíveis à temperatura de operação. Para a mesma capacidade (25kW), a geração efetiva de energia da planta de módulos flexíveis é 9,1% maior devido à área de incidência receber 63,3% mais irradiação solar. As menores eficiências elétricas ocorrem no Verão/Primavera, entretanto, as plantas geram 30% mais energia em relação ao Outono/Inverno. Na atualidade, os módulos monocristalinos possuem melhor aplicabilidade do que os flexíveis, pois possuem maior eficiência elétrica, mesmo utilizando estruturas de suporte mais robustas. / Due to the high demand for the replacement of energy sources that use fossil fuels by renewable energy sources, the current science seeks to maximize the efficiency of renewable sources to them be economically competitive in the market. Much of the Brazilian leadership in this field is due to the hydraulic source, which negatively impacts the environment and the riverine populations. Thus, other renewable energy sources such as wind and solar energies have increased their participation in the country's energy matrix. Given this context, photovoltaic systems with high efficiency can increase the participation of solar energy in the internal matrix of electric energy of Brazil. Floating photovoltaic systems are 11% more efficient than onshore systems due to lower operating temperatures. To determine if the relative humidity of the air influences the efficiency of the floating plants; in this work, based on a numerical analysis, it was evaluated whether the energy conversion efficiency is influenced by the distance between the water surface and the floating photovoltaic module. In addition, it was studied two different types of photovoltaic modules (monocrystalline and flexible) during the 4 seasons of the year, evaluating its peculiarities. The Rosana/SP Photovoltaic Plant was used as the basis for the formulation of the physical models, which resulted in a mathematical model solved through the Finite Volume Method in the FLUENT® and MECHANICAL® softwares of the ANSYS® package. The four simulated distances (100, 300, 600 and 900mm) determined that the physical and mathematical models adopted did not capture in a conclusive way whether the operating temperatures of the modules decrease with the approximation of the water surface. The power generated by a monocrystalline module is 38.8% greater than that generated by a flexible module, however the monocrystalline is ten times more sensitive to the operating temperature. For the same capacity (25kW), the effective power generation of the flexible module plant is 9.1% higher due to the incidence area receiving 63.3% more solar irradiation. The lowest electrical efficiencies occur in the Summer/Spring season, but generate 30% more energy compared to Fall/Winter season. Currently, the monocrystalline modules have better applicability than the flexible ones because they have greater electrical efficiency, even using more robust support structures. / 130005/2016-9

Orientador: João Batista Campos Silva / Resumo: Devido à alta demanda da substituição de fontes de energia que utilizam combustíveis fósseis por fontes de energia renovável, a ciência atual busca maximizar a eficiência das fontes renováveis para que sejam economicamente competitivas no mercado. Grande parte da liderança brasileira neste campo se deve à fonte hidráulica, que impacta negativamente o meio ambiente e as populações ribeirinhas. Assim, outras fontes renováveis como a eólica e a solar têm aumentado sua participação na matriz energética do país. Diante deste contexto, sistemas fotovoltaicos com alta eficiência podem aumentar a participação da energia solar na matriz interna de energia elétrica do Brasil. Os sistemas fotovoltaicos flutuantes são 11% mais eficientes do que os sistemas instalados em terra devido às menores temperaturas de operação. Para determinar se a umidade relativa do ar tem influência na eficiência das plantas flutuantes, neste trabalho, a partir de uma análise numérica, avaliou se a eficiência de conversão de energia é influenciada pela distância entre a superfície da água e o módulo fotovoltaico flutuante. Além disso, estudou dois tipos diferentes de módulos fotovoltaicos (monocristalinos e flexíveis) durante as quatro estações do ano, avaliando suas peculiaridades. A Planta Fotovoltaica de Rosana/SP foi utilizada como base para formulação dos modelos físicos, que resultaram em um modelo matemático solucionado através do Método de Volumes Finitos nos softwares FLUENT® e MECHANICAL® do pacote A... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to the high demand for the replacement of energy sources that use fossil fuels by renewable energy sources, the current science seeks to maximize the efficiency of renewable sources to them be economically competitive in the market. Much of the Brazilian leadership in this field is due to the hydraulic source, which negatively impacts the environment and the riverine populations. Thus, other renewable energy sources such as wind and solar energies have increased their participation in the country's energy matrix. Given this context, photovoltaic systems with high efficiency can increase the participation of solar energy in the internal matrix of electric energy of Brazil. Floating photovoltaic systems are 11% more efficient than onshore systems due to lower operating temperatures. To determine if the relative humidity of the air influences the efficiency of the floating plants; in this work, based on a numerical analysis, it was evaluated whether the energy conversion efficiency is influenced by the distance between the water surface and the floating photovoltaic module. In addition, it was studied two different types of photovoltaic modules (monocrystalline and flexible) during the 4 seasons of the year, evaluating its peculiarities. The Rosana/SP Photovoltaic Plant was used as the basis for the formulation of the physical models, which resulted in a mathematical model solved through the Finite Volume Method in the FLUENT® and MECHANICAL® softwares of the ANSYS® package.... (Complete abstract click electronic access below) / Mestre

Deposition of dispersed phase from flowing dispersions onto a substrate surface is of utmost relevance for various industrial processes like fouling of sparingly soluble salts, such as CaCO3 and CaSO4 in heat exchangers and desalination evaporators which tend to form deposits on flow surfaces of tubes or pipelines conveying hard water and in water filtration and purification processes since concentration of CaCO3 in many natural water resources is equal to or greater than the saturation level. The study of deposition is also of intrinsic interest for biophysics and colloid science where vascular calcification i.e. precipitation and deposition of calcium phosphates (hydroxyapatites) in the muscular layer of the blood reduces arterial compliance and promotes congestive heart failure. Experiments were conducted on straight, circular cross section silica tubing of inner di-ameter (ranging from 0.88 mm to3.40 mm) to study the effect of electrostatic interaction and hydrodynamics on the deposition behavior of CaCO3 on silica surface when streams of aqueous solutions of Ca(NO3)2 and Na2CO3 with a concentration of 40.0 g l−1 and 25.9gl−1 respectively flowing at a volumetric flow rate of 1 l h−1 each is mixed to form CaCO3 dispersion which was then transported through silica tubing at a steady volumetric flow rate of 2lh−1. The in situ phenomenology of CaCO3 particles transport, deposition, and evolution of spatial and temporal patterns of the CaCO3 deposition on the silica surface along with the dendritic growth of CaCO3 during the flow was visually documented with the aid of a 100X optical microscope. The study discussed the deposition behavior of dispersed phase of CaCO3 from its aqueous dispersion on the silica tubing during flow and attributed charge inversion from negative to positive of silica surface, due to the adsorption of Na+ formed during precipitation reaction of CaCO3, as a plausible reason for the reversal of electrostatic interaction from attraction between initially negatively charged silica surface and positively charged CaCO3 particles which promoted deposition and subsequent evolution of patterns of CaCO3 deposition on the silica surface during the early stage of experiments to repulsion between finally net positively charged silica surface and positively charged CaCO3 particles which resulted in retarded deposition and subsequent emergence of sparsely adhered CaCO3 agglomerates as localized, limited patches of CaCO3 deposits on the silica surface during the later stage of the experiments

At the beginning of thesis I want to describe few primary characteristics of the South Bohemia Region. It is a region with unique characteristics, which is frequently visited by domestic and foreign tourists. It is popular for its clean environment, historic monuments and especially for sport and recreational activities near water areas, which South Bohemia region has plenty of. Tourists are also frequently seeking recreational boating activities as ferry services for their travel and recration. The development of this economic phenomenon means more employment opportunities for the region, but it also increases chances of accidents and emergencies due to an unforseen accidents which can threaten the lives and wellbeing of the crew and the environment. Fire protection units should be fitted for an emergencies such as: drowning, drowned person search, icy water search and rescue and rescue in stream waters. The thesis is divided into the theoretical and the practical parts. The theoretical part deals with the definition of basic terms describing the issue of fire of the vessels as well as the tasks and procedures during fire fighting operations. It also presents a possible danger to rescuers exposed during operations such as rescue from the vessel burning on the water. There is a listing of the basic terms related to the complex vessel shape and the aquatic characteristics of the vessel. The practical part deals with the study of publications and current legislation, analysis of the Fire protection Units equipment and their readines for rescue work in case of a vessel fire. The enclosed data map illustrates a water area with ferry service in the South Bohemia Region and selected boarding platforms for fire protection units. It describes the use of container technology; modern and economical way of transportation used by the Fire and Rescue Service of South Bohemia Region since 2004. The proposed fire vessel, mounted on a standardize container frame and equipped with special container with stored technical equipment will be transported to the location of event by container carrier from FRS of South Bohemia Region. My theosis also describes the fire protection, fire equipment, personal protective equipment, equipment for working with hazardous substances, rescue tools, communication and portable emergency equipment which is normally used by the fire units of FRS of South Bohemia Region. To achieve the objective of the thesis and to answer the research questions, I did rely on the reference material obtained via search of the professional literary sources relevant to the Fire Fighting equipment and carrying out rescue work. To process the diploma thesis I did use the following: controlled interview with the station sergeants of various fire stations of FRS of South Bohemia, a collection of internal acts of the Ministry of Interior - General Directorate of Fire Rescue Service of the Czech Republic, a collection of internal acts - Regional Directorate of FRS of South Bohemia, Regulations of Mechanical services of FRS of CR and the methodological aids of the Ministry of Interior of CR. In conclusion I am describing the container of fire vessel and its use for rescue and fire-fighting work on water, as well as places where the terrain does not allow the use of mobile fire fighting equipment.

Um historische Durchflussangaben an Flüssen, die in die Hochwasserstatistik eingehen, überprüfen und bewerten zu können, werden 1-D- und 2-D-Wasserspiegellagenberechnungen unter Verwendung historischer morphologischer Daten durchgeführt. Die Methodik sowie ihre Möglichkeiten und Grenzen werden am Beispiel der Elbe im Stadtgebiet von Dresden erläutert.Es wird deutlich, dass die notwendigen Korrekturen auch Auswirkungen auf die Hochwasserstatistik und damit auf die Schutzgrade haben.