Os vertedores são estruturas hidráulicas construídas para controlar o nível d’água do reservatório, permitindo a passagem das vazões escoadas com a máxima eficiência possível sem provocar problemas à estrutura. Para atingir este objetivo, as condições de aproximação do escoamento à estrutura e a forma geométrica do perfil vertente são muito importantes. O controle da soleira por comportas provoca uma mudança significativa nas condições de escoamento sobre o perfil vertente. O posicionamento e a forma da comporta tem forte influência no comportamento do coeficiente de vazão e nas pressões sobre a soleira. A formação de vórtice é um fenômeno indesejável que pode ocorrer quando a operação da comporta é parcial, prejudicando a capacidade de vazão e provocando vibrações na estrutura. Este trabalho apresenta uma abordagem teórica sobre o assunto vertedor de superfície e escoamento sob comportas, apresentando resultados de diferentes estudos para melhor compreensão do funcionamento do vertedor. / Spillways are hydraulic structures constructed to control the water level of the reservoir, allowing the overflows with the maximum possible efficiency without provoking problems to the structure. The approach flow pattern to the structure and the geometric form of the spillway profile are basic importance. The control of the spillway by the floodgates modifies the draining conditions. The positioning and the form of the gate have strong influence in the behavior of the discharge coefficient and the pressures on the surface profile. A vortex formation is an undesirable phenomenon that it can occur when the operation of the floodgate is partial, reducing the discharge coefficient and produce vibrations in structure. This work presents a theoretical approach about flow over spillway and under of the partial opening of the floodgate, presenting results of different studies for better understanding the function of the spillway.

Neste trabalho é apresentada a solução das equações que regem o escoamento unidimensional não permanente em dutos sob pressão por meio do esquema numérico de MacCormack, esquema este, já empregado nos escoamentos transientes em condutos livres. É apresentada, também, a comparação dos resultados obtidos com a aplicação do esquema de MacCormack em relação aos obtidos através do método das características, na solução de transientes hidráulicos em condutos forçados. / This dissertation introduces the MacCormack numerical scheme for the solution of the one-dimensional unsteady pressurized flow equations, this scheme is already employed for solving open-channel transient flows. It is presented, also, the comparison of the results obtained from the application of the MacCormack numerical scheme with the obtained using the Method of the Characteristics, in the solution of hydraulic transient in pressurized flow.

O avanço tecnológico tem proporcionado à indústria em geral desenvolver e fabricar produtos mais sofisticados em todos os campos da ciência. Não distante dessa realidade, a indústria da mobilidade também vem incorporando, através de projetos arrojados, as novas tecnologias em seus produtos, respondendo, assim, às necessidades e expectativas de seus clientes, que exigem produtos com maior produtividade e disponibilidade para trabalho. Essas tecnologias estão relacionadas com os sistemas de transmissão de força por fluidos, através da introdução de válvulas eletro-hidráulicas e também pela redução da tolerância entre partes deslizantes e rotativas desses sistemas. A partir da introdução dessa nova tecnologia, a ênfase desse trabalho foi mostrar a importância do controle de contaminação nas fases do processo de concepção, fabricação e montagem do produto, incluindo a quebra de paradigmas relacionada ao fator humano e, em especial, o controle de contaminação do fluido de transmissão de força utilizando a tecnologia de contagem de partículas. Assim, foi evidenciado que através da determinação de limites aceitáveis de contaminação para cada tipo de sistema de transmissão de força, em função do tipo de tecnologia agregada, é possível reduzir drasticamente as falhas nos sistemas de transmissão de força por fluido durante a operação do produto no campo, mesmo sendo essa contaminação considerada um inimigo invisível. / The technological advance has proportionated to the industry in general to develop and to manufacture more sophisticated products in all the fields of science. Not distant of this reality, the industry of mobility also comes incorporating through bold projects the new technologies in its products, thus answering to the needs and expectations of its customers, who ask for products with high productivity and availability to work. These technologies are related with the power transmission systems by fluids through the introduction of electrohydraulic valves, and also by the reduction of tolerance between smooth and rotary parts of the system. From the introduction of this new technology, the emphases of this dissertation was show the importance of the contamination control in the process phases of conception, manufacturing and assembly of the product, including brake the paradigm related with human factors, and specially the fluid contamination control of the power transmission using the particle counting technology. To show that through the determination of acceptable limits of contamination for each type of power transmission system, as a function of the type of added technology, it is possible to drastically reduce the failures in the power transmission systems by fluids during the operation of the product in the field, even being this contamination considered an invisible enemy.

Rejeitos de mineração com muita freqüência são dispostos na forma de lama. A capacidade de estocagem das lagoas onde são depositados depende de suas dimensões e formas de operação, mas também das características físicas, compressibilidade e condutividade hidráulica da lama. No presente trabalho estudam-se as características de consolidação de uma lama argilosa resultante da mineração de areia, por meio do ensaio de consolidação hidráulica (HCT) e modela-se o enchimento de uma lagoa de disposição desse rejeito, empregando a teoria de grandes deformações e mediante o software CONDES. Realizaram-se ensaios de caracterização e HCT com amostras coletadas das lagoas 2, 11 e vertedouro da Mineração Jundu Ltda. em Descalvado, São Paulo. Estes parâmetros foram necessários para as análises de simulação numérica do processo de enchimento da Lagoa 11. Os resultados dos ensaios HCT mostraram um conjunto consistente de propriedades constitutivas do material, também se verificou a importância de alcançar a condição estável nas leituras da diferença de pressão entre o topo e a base do corpo de prova, assim obter uma menor variabilidade dos resultados. A simulação de enchimento se mostrou consistente, onde se obteve a evolução do processo de consolidação em diferentes etapas do lançamento da lama. Observou-se uma concordância dos resultados obtidos na simulação de enchimento. Segundo as análises observou-se que a altura dos rejeitos após um período de dois anos é da ordem de 1.57 m. / Mining waste is frequently disposed of in the form of mud. The storage capacity of a collection reservoir of mining waste depends on its dimensions and on its operational processes, which are based on the physical characteristics of the mud and its compressibility and hydraulic conductivity. This research focuses on the study of the consolidation characteristics of a clayey mud resultant from the process of sand mining. Such characteristics were studied through Hydraulic Consolidation Tests (HCT) and by modeling the waste reservoir filling process using large deformation theory and the CONDES software. Characterization and hydraulic consolidation tests were performed on samples obtained from Reservoirs 2 and 11 and from the Jundu Mine spillway at Descalvado City in the state of São Paulo, Brazil. The characterization parameters obtained were employed in performing numerical analysis of the filling process of waste reservoir 11. HCT test results show the acceptable set of constitutive properties of the analyzed material. During the testing procedures, variability of test results were minimized by obtaining stabilized pressure difference readings between the top and bottom leads of the specimen. Modeling was conducted for instantaneous and progressive filling and both methods yielded the same results. It was observed a predictable parity between the results obtained from instantaneous and progressive filling simulations. The final height after consolidation was measured at approximately two years for both instantaneous and progressive methods of filling. From the analysis, the two-year level was measured at 1.57 meter.

Rubble-strewn corridors, stairs and steep natural terrain all present a challenge for wheels and tracks. Legs are a solution in these cases because foot placement allows the traversal of discontinuous terrain. Legged robots, however, currently lack the performance needed for practical applications. This work seeks to address an aspect of the problem, foot placement while running. A novel hopping height controller for a spring-loaded legged robot is presented. It is simple and performs well enough to allow control of the ballistic trajectory of hops and therefore foot placement. Additionally, it can adapt to different ground properties using the result from previous hops to update control gains. A control strategy of extending the leg at a fixed rate during the stance phase and modulating the rate of extension on each hop was used to control the hopping height. The extension rate was then determined by a feed-forward + proportional control loop. This performed sufficiently well allowing the ballistic trajectory of hops to be controlled. In simulation, the spring-loaded inverted pendulum (SLIP) model was extended to include actuation and losses due to friction. The control strategy was developed using this model then, in a planar simulation, the controller was run to perform foot placement while running over a series of platforms which vary in their horizontal and vertical spacing. To experimentally validate and further develop the control strategy, a one-legged hopping robot, constrained to move vertically, was used. The leg had 2 links, hydraulically actuated hip and knee joints and a spring-loaded foot. Results showed that the controller developed could be used to perform hops of randomly varying size on grounds with different properties and while running on a treadmill at different speeds. As an aside, the dynamics of hydraulic actuators presented a problem for foot repositioning during flight using a simple PID controller. This was solved through the novel implementation, in hydraulics, of a `zero-vibration' (ZV) filter in a closed-loop. Simulation and experimental results demonstrating this are presented.

BACKGROUND: Over the past decade hydraulic fracturing, the high-pressure injection of water and chemicals into an oil or gas well, has been widely adopted to maximize oil and gas recovery despite debate about potential health impacts. Often the debate is contentious and complicated by incomplete information. The purpose of this dissertation was to implement and assess the usefulness of a process for communities to identify, prioritize, and respond to potential health effects of hydraulic fracturing. METHODS: The study was conducted in a community in Kern County, California, the epi-center of hydraulic fracturing in the state. Mixed methods were used to develop an inventory of known or potential health effects associated with exposure to hydraulic fracturing: a systematic review of literature published before April 1, 2017 to determine health outcomes reported in exposed communities; a Delphi study to elicit expert opinion; and focus groups to determine residents’ health concerns. The resulting inventory of 60 health effects derived from one or more of these sources was presented to community residents in ballot form and multi-voting was used to prioritize health effects. Focus group and multi-voting results were used to develop an action plan. RESULTS: The Delphi panel endorsed 13 health outcomes associated with hydraulic fracturing for oil and/or gas; all but one were reported in the scientific literature. Focus groups generated 17 health effects; 13 of these were reported in the scientific literature and/or endorsed by the Delphi panel. Multi-voting results indicated that priority health effects were: problems with sleep; breathing; eyes, ears, nose, and throat; heart disease and hypertension; cancer; headache; nausea; and a group of symptoms known as “Shale Gas Syndrome”. CONCLUSION: The process described in this dissertation could be used by communities across the US that are debating the potential health impacts of hydraulic fracturing. It engages community residents, requires few resources, and can be completed in a relatively short period of time. The results can inform a community-specific response to the priority health concerns identified.

A pilot scale study of the dynamics of the break-up of curved liquid jets is presented. This work is motivated by an industrial process called prilling which is used in the manufacture of pellets. In this process a sieve-like cylindrical can spins rapidly on its central vertical axis. Molten liquid is pumped into the top of the can and flows from the holes in the form of curved liquid jets. Experiments are described which were carried out on a pilot scale rig. Some differences between the break-up modes observed in this study and previous work using a small laboratory scale rig are discussed. Previous theories describing break-up mechanisms of curved liquid jets were extended to include viscosity and gravity. Break-up lengths and drop sizes were obtained theoretically and compared with experimental results. Experiments were carried out using insonification, a process where sound waves are fired at the jet to control satellite drop formation. Three different frequencies of wave were used, 10, 100 and 200 Hz at four different rotation rates. It was observed that insonification was successful at eliminating satellite drops at low rotation rates and when frequencies of 100 or 200 Hz were used. Insonification was included in the theory. The theory predicted that insonification eliminated satellite drops for a large range of frequencies in the experimental regimes for sufficiently large acoustic volume. The theory also predicted that satellite drops were eliminated in parameter regimes outside the experimental regimes. The trajectory of the jet was allowed to become unsteady, in a rotating frame of reference. Simulations were carried out in inviscid and viscous regimes.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Ocean Engineering. / Includes bibliographical references. / by J. Kim Vandiver. / Ph.D.

Thesis. 1975. B.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Bibliography: leaf 39. / by Eric Hershler Bott. / B.S.

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Includes bibliographical references. / M.S.