The subject of this diploma thesis is a comparison between two river hydraulics modeling approaches, the first one being combined 1D and 2D modeling, and the second one being solely 2D modeling. Both models are located at Bečva river, between its 17,282 and 28,419 river kilometer. The outputs of the simulations are water flow velocity maps, water depth maps, maps that show differences between flood areas calculated in both models, tables comparing channel water surface elevations and schematic long sections. In conclusion of the thesis, the outputs of the simulations are compared.

As embarcações projetadas na atualidade possuem dimensões muito superiores às empregadas no passado recente do transporte marítimo, tanto para os navios de carga, quanto para os navios de cruzeiro. Esta realidade tem suas vantagens, permitindo o transporte de maior volume de cargas e passageiros, reduzindo os custos agregados às mercadorias e pessoas transportadas, mas, em contrapartida, traz desvantagens, pois essas embarcações possuem maior área exposta às ações ambientais, como ventos e correntes. Além disso, existe a demanda de amplos espaços náuticos, particularmente lâminas d\'água, e auxílio de rebocadores para acesso e atracação destas embarcações. Para reduzir os custos com as operações de dragagem, mais terminais portuários são construídos em áreas expostas a condições ambientais mais severas. Todas estas condições implicam diretamente no comportamento das embarcações atracadas, pois estas poderão estar sujeitas a movimentos de grande amplitude, suscetíveis de reduzir a eficiência e a segurança com que as operações de movimentação de carga são realizadas, podendo obrigar a sua interrupção e, nos casos mais críticos, provocar a ruptura das linhas de amarração e/ou danos nas defensas, podendo causar danos na estrutura de acostagem e na própria embarcação eventualmente, ocasionando vítimas. Levando em conta todos estes fatores, existem métodos pelos quais é possível o desenvolvimento de planos de amarração para conter os movimentos da embarcação durante a movimentação da carga e passageiros, buscando sempre obter o máximo de segurança nas operações no cais. Ainda para a verificação da eficácia e otimização dos planos de amarração, antes da sua implantação no terminal, existem métodos de análise, em que é possível estimar as forças exercidas nos cabos das linhas de amarração. Desta forma, este trabalho propôs-se a realizar uma pesquisa comparativa do emprego dos métodos analítico e de modelagem física. Assim, obteve-se uma avaliação crítica quanto à estimativa de esforços nos cabos das linhas de amarração de embarcações atracadas sob a ação de correntes. / Currently designed vessels have dimensions much higher than those used in the recent past of shipping, both for cargo ships and for cruise ships. This reality has its advantages, allowing the transportation of a larger volume of cargo and passengers, reducing the aggregate costs to the goods and people transported, but, on the other hand, it has disadvantages, since these vessels have greater area exposed to environmental actions, such as winds and currents. In addition, there is a demand for large nautical spaces, particularly water slides, and assistance of tugs for access and mooring of these vessels. To reduce costs with dredging operations, more port terminals are built in areas exposed to more severe environmental conditions. All these conditions directly imply the behavior of moored vessels, as these may be subject to large-scale movements, which may reduce the efficiency and safety with which the cargo handling operations are carried out, and may cause them to be interrupted and in the worst-case scenario,, damage the fenders and the berthing structure the vessel itself possibly causing casualties. Taking into account all these factors, there are methods by which it is possible to develop mooring plans to contain the movements of the vessel during the movement of the cargo and passengers, always seeking to obtain maximum safety on the dockside operations. In order to verify the efficacy and optimization of the mooring plans, prior to their implementation in the terminal, there are methods of analysis, in which it is possible to estimate the forces exerted on the ropes of the mooring lines. In this way, this work proposes to carry out a comparative research of the use of analytical and physical modeling methods. Thus, a critical evaluation was obtained regarding the estimation of efforts in the cables of the mooring lines of vessels moored under the action of currents.

Artificial recharge and rainwater harvesting methods are being applied for mitigating effects of groundwater depletions in severe over-drafting urban and rural situations. When the aquifer to be recharged is situated at some depth below the ground surface and topped by a semi-previous layer with a large resistance against vertical water movement, recharge wells are the most appropriate solution. Water is injected by free or forced recharge technique by maintaining constant or variable head or rate of injection in the recharge well. A review of literature, carried out in two parts, looks into the aspects and performance of the practical field applications of recharge wells all over the world in Chapter II, whereas available theoretical solutions are reviewed in chapter III. The review indicates that free recharge conditions are analysed using slug theories and mirror image type curve analysis is helpful in dealing with forced recharge cases. Many slug test and pumping test theories developed focus either on simplistic recharge conditions or homogeneous hydro-geological conditions. Also, separate developments exist in the areas of large diameter well and flow to multi-aquifer system. These developments are mainly concentrated on constant wellhead boundary conditions with no well loss. Many researchers have dealt effect of pumping on base flow numerically, but the study on the impacts of recharge on base flow has not been noticed. One more practical issue, which has not been studied, is the aquifer clogging during well injection, though related background research on filtration phenomena is comparatively well established. Analytical solution for recharge in a finite aquifer from a large diameter well under variable head is obtained in Chapter IV. Furthermore, issues of analytical solution difficulty, in the available solution with constant head boundary condition are resolved and extended using Discrete Kernel approach to variable heads. Usefulness of choosing the variable head boundary condition lies in the advantage that continuous pouring of water in to the recharge well is not a necessary condition. As well and aquifer clogging is minimum in hard rock terrains, present solution is useful for estimating the pressure heads and recharge rates in the well flooding techniques frequently used in hard rock regions. For the case of free recharge in confined aquifers, available slug test theories do not consider appropriate well storage and well loss, as these may not be significant in the case of short duration test with instantaneous slug. Also slug theories are not extendable to multi-aquifer wells. Analytical solutions are obtained for free recharge condition for both single and multiple layer aquifers in chapter V, also incorporating well loss, well storage and friction loss. Parametric studies are made to see the effect of hydro-geological parameter namely; transmissivity and storativity, on recharge rates and head buildups. Theis (1935) solution is provided with well storage effects for the entire period of recharge, using Duhamel’s convolution theorem. Comparison with Cooper et al. (1967) shows, that the present solution could be useful for long-term non-instantaneous free recharge data analysis. Relationship between diffusivity and time to decay has been developed, which is useful for aquifer parameter estimation using recharge test data. Similar improvement is feasible for other existing type curves also including leaky aquifers. Analytical solutions for free recharge with constant well loss, variable well loss and losses due to friction have been developed. Comparison indicates better solution with losses due friction, which is also a more easily measurable physical parameter as compared to other well loss constants. Free recharge solutions provide unique opportunity to estimate the recharge rates in the individual aquifers of single and multi-layered aquifer. Well bore interaction has been accounted through recharge well injecting water to multi-aquifers. Specific analytical solutions are developed for the cases of free recharge in hard rock multi-layered aquifers. Present state of the art for recharge well considers forced recharge as mirror image of the pumping test solutions, type curves of which are found more difficult to fit in to the recharge test data. Again, deviation in type curve match lies in considering well storage, well clogging and aquifer clogging effects. In chapter VI analytical forced recharge solutions are developed for constant and variable rate of injection. Mirror image Theis (1935) solution is coupled with well storage during the recharge period to improve the existing solution and make it suitable for recharge computation after comparing it with Popodopulos and Cooper (1967) solution. Well bore interaction in case of multi-layered aquifer has been considered. Similar exercises are possible with existing solutions other than Theis (1935) including those for leaky aquifers. Type curves for recharge for various diffusivity ratios have been developed. Constant and variable well loss is considered for forced recharge in single as well as multi-layered aquifer. Results say that present solutions are more accurate in terms of well storage, which has significant influence on well injection as compared to well pumping. In the case of pumping, well storage effects are dominant in the initial times, where as it effects the entire recharge cycle, also depend upon the aquifer diffusivity and the recharge column dimensions. Significant influence of well loss in case of forced well recharge has been taken care of by considering linear trend of deteriorating well condition between times dependant Walton’s well loss constant. In Chapter VII, aquifer clogging, changing with time has been analysed using numerical modelling technique and applying the results of the filtration experiments reported in the literature. Inclined initial piezometric water table condition is found effective towards observation well water level and is considered for simulation of the observation well water level of Hansol project. The methodology is transferable for analyzing other injection project also. Base flow on regional scale is affected by the location, rate of injection and number of wells. In the case of Bamnod injection well project, base flow retained in the aquifer, is reducing with the increase in the quantity of injected water. This conclusion may not always be same everywhere, however, this aspect needs to be investigated. Chapter VIII summaries and highlights the conclusions drawn out of the present research study. It has been summarized that the Chapters IV, V and VI develop analytical solutions for recharge rates under unsteady wellhead condition by coupling existing groundwater flow solution with Duhamel’s convolution theorem. It provides the well storage effects throughout the recharge cycle, which unlike in pumping cases, could be significant in recharge cases. Second foremost specific requirement for a well recharge may be the consideration of head loss. In free recharge cases friction factor per unit diameter of recharge well is found a better physically computable parameter, where as well loss constants suggested by Walton (1962) could bring the head loss effects in the developed solutions for forced recharge. Free and forced recharge solutions developed for single aquifer are further extended to multi-aquifer system with respective head loss effects and well bore interaction. This is an useful contribution owing to the fact that no multi-aquifer solution considers aquifer interactions through recharge well and equivalent single aquifer theory worked for the multi-aquifer system without head loss All the solutions in Chapters IV, V and VI are found sensitive towards well radius and could analyze recharge behavior at the well face with horizontal initial piezometric surface. Simulation of the response in an observation well situated 50 m away from the recharge well is found inappropriate with the present solution. Therefore in the Chapter VII, to solve the solution difficulty, analysis is extended for the observation well, some distant away from the recharge well face, using numerical solution technique. Heterogeneity in the flow medium between the recharge well and the observation well is considered as per the time dependant aquifer clogging, based upon theory of filtration. Recharge well in general has been considered as a technology, which would increase the groundwater storage. With a case study it is found that groundwater regime also plays a crucial role in this respect. Present thesis also provides specific solution to practical issues like; estimation of diffusivity from time to decay of recharge, friction loss in the recharge well, time variant well loss as per recharge well condition, effect of sudden pump shut down, control of injection rates against recharge well over flooding, recharge rates to individual aquifers of a multi-aquifer system and multiple well recharge options. Though the scope of the present research is confined to aquifer-aquiclude system only, it could easily be extended to various other hydro-geological setups also. Unique feature of the applied analytical solution technique lies in the flexibility of transformation between head and flux boundary conditions. This provides an opportunity to compute recharge rates and corresponding heads simultaneously with any kind of boundary conditions.

This master´s thesis deals with ventilation of synchronous generators with a cylindrical rotor. For the design of ventilation we apply basic physical laws in the field of hydromechanics and thermomechanics. Therefore the first chapters are devoted to these subjects. They are followed by the description of ventilation systems and a thermal net is created and solved for one of them consisting of the thermal resistance and sources. The final part deals with a program, which I developed in Visual Basic 2008 Express Edition. This program enables to calculate the ventilation and heating of individual parts of the machine after entering basic machine dimensions and losses.

Lärande med elektroniska medel har potentialen att revolutionera lärande. Via datorskärmen kan man enkelt åskådliggöra fysikaliska fenomen och underlätta arbetet för läraren. Om en utbildning bedrivs elektroniskt med hjälp av en dator och på distans uppstår en del svårigheter men samtidigt möjligheter, jämfört med en traditionell utbildning med fysisk närvaro i en skola. Datorer ger möjligheten att ta hänsyn till pedagogiska aspekter som kan effektivisera lärande. I dagens läge finns det inte ett utarbetat sätt att lära ut med elektroniska medel som garanterar ett gott lärande resultat. Hur en elektronisk kurs utformas är upp till läraren och institutionen som erbjuder kursen. I denna rapport ger vi ett enkelt förslag på hur vi anser en elektronisk kurs bör vara utformad samt det innehållet i kursen bör täcka. / Teaching by electronic means has the potential to revolutionize teaching. The screen of the computer can easily visualize physical phenomenon and facilitate the work of the teacher. If an education is conducted electronically and by distance it creates some difficulties but at the same time opportunities, compared to traditional education with a physical presence at a school. Today there is no prepared way to teach by electronic means that guarantees good teaching results. How an electronic course is formed is decided by the teacher and the institution offering the course. In this report we give a simple suggestion of how we consider an electronic technics course should be formed and what the course content should cover.

Climate change and economic opportunities motivate investigating electric distributed power for working hydraulics in non-road mobile machinery (NRMM) instead of conventional hydraulics. This recent method allows significant energy savings in hydraulic systems, which was demonstrated previously by many independent studies. In this study, zonal hydraulics (as electrically distributed) are realized with direct driven hydraulics drive (DDH) units. Unlike conventional hydraulic drives the DDH units are disconnected from the engine (main prime mover) and distributed throughout the system. In a DDH unit, a single fixed displacement pump/motor with a speed-controlled electric servomotor directly controls the flow. The aim of this paper is to determine functionality of this new two-cylinder DDH-system in a lifting work cycle (or a swerve motion of the work machine). For this purpose, a model was created to investigate performance of the new test rig Dolores. The results of the simulation model will be utilized in future research to discover and compare other alternatives for working hydraulics architectures.

One of the largest energy losses in an excavator is the compensation loss. In a hydraulic load sensing system where one pump supplies multiple actuators, these compensation losses are inevitable. To minimize the compensation losses the use of a multi chamber cylinder can be used, which can control the load pressure by activate its chambers in different combinations and in turn minimize the compensation losses.  For this proposed architecture, the control of the multi chamber cylinder systems is not trivial. The possible states of the system, due to the number of combinations, makes conventional control, like a rule based strategy, unfeasible. Therefore, is the reinforcement learning a promising approach to find an optimal control.  A hydraulic system was modeled and validated against a physical one, as a base for the reinforcement learning to learn in simulation environment. A satisfactory model was achieved, accurately modeled the static behavior of the system but lacks some dynamics.  A Deep Q-Network agent was used which successfully managed to select optimal combinations for given loads when implemented in the physical test rig, even though the simulation model was not perfect.

I investigated streambed stability in spawning microhabitats of warmwater fishes in the upper Roanoke River, Virginia. Spawning microhabitats used by four reproductive guilds (egg-clusterers, mound-builders, egg-buriers, and pit-builders) were identified and ranges of 15 microhabitat variables used by each guild were compared to available microhabitat conditions to investigate habitat selection. Habitat usage by egg-clusterers was most characterized by selection for spawning rocks in the cobble size range, substrate roughness elements in the cobble to boulder size range, high roughness Reynolds number and moderate water column velocity. The mound-building bluehead chub (Nocomis leptocephalus) was distinct in its selection of substrate in the small gravel range, low water velocity and non-turbulent flow. Egg-buriers were the least distinct of the four guilds, exhibiting much variation in habitat use among the component species. However, all species used areas with small substrate (sand to gravel range), high velocity, and high turbulence. The pit-building central stoneroller (Campostoma anomalum) was distinct in its usage of areas with high velocity and turbulence, gravel sized substrate, and low embeddedness. Stability of each guild's spawning microhabitats was empirically evaluated through analysis of tracer particle movement and repeated surveying of bed elevation along stream transects. Logistic regression equations developed from tracer particle data predicted that microhabitats selected by egg-clusterers are among the most stable of all available habitats during high flows. Microhabitats utilized by mound-builders, egg-buriers, and pit-builders are predicted to be less stable. Repeat transect surveying corroborates model predictions in that egg-burier habitats experienced changes in bed elevation in high flows, while egg-clusterer habitats did not. / Master of Science

The automation of hydraulic mobile machinery, such as excavators, requires high performance control solutions. In hydraulics, this means fast and accurate force, velocity and position control of hydraulic cylinder. Especially the force control is known to be difficult with traditional servo valves. Fast digital hydraulic valves together with modern control solutions can overcome this problem. This paper uses a new force control solution, which is based on the fast digital hydraulic valves and model based control principle. The control solution is applied in a heavy axis mimicking dynamics of mobile machine booms. Experimental results show good force, velocity and position tracking performance with varying load masses. The slow velocity performance is also much improved when compared to the earlier results.

Digital hydraulics is one of promising technologies having a huge potential to significantly improve energy efficiency in the fluid power industry. In this paper, we present a digital hydraulics solution for mobile market with a large ammount of energy usage by hydraulic components and systems. Specifically, a novel hydraulic architecture, Multiplex Digital Valve (MDV) system that employs digital valves to meet multiple service pressure/flow requirement in off highway vehicles, is introduced. With MDV being integrated in an execavator, signficant hydraulic power saving have been validated compared to the baseline machine with the negative flow control (NFC) architecture. In addition, considering noise is still a critical hurdle for digital hydraulics to be adoped, we develop several noise reduction methods that have been evaluated in simulation environment and implemented in the above MDV. The sound pressure measured from the retrofitted MDV solution with the NVH treatment in the excavator has been improved signficantly over the untreated system such that it is nearly comparable to the baseline machine. The paper also briefly presents the sound quality study for better understanding of human perception and acceptance to nonconventional sound.