Thesis (Ph. D.)--Technische Universiteit Delft, 1988. / Vita. Includes bibliographical references.

Submitted by Leonardo Paioli Carrazza (leopcarrazza@hotmail.com) on 2016-04-05T22:42:13Z No. of bitstreams: 1 Dissertação_Leonardo_Paioli_Carrazza.pdf: 3964409 bytes, checksum: c0e32a8f0bc03d0337063173dd600bcd (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-07T14:29:31Z (GMT) No. of bitstreams: 1 carrazza_lp_me_rcla.pdf: 3964409 bytes, checksum: c0e32a8f0bc03d0337063173dd600bcd (MD5) / Made available in DSpace on 2016-04-07T14:29:31Z (GMT). No. of bitstreams: 1 carrazza_lp_me_rcla.pdf: 3964409 bytes, checksum: c0e32a8f0bc03d0337063173dd600bcd (MD5) Previous issue date: 2016-03-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A expansão urbana desordenada pode gerar graves consequências ao ambiente. A falta de planejamento no escoamento de águas pluviais, aliado à baixa coesão de alguns terrenos pode proporcionar o surgimento de voçorocas, cuja evolução pode resultar em riscos geotécnicos para a população ao redor. Neste sentido, a geofísica possibilita um diagnóstico de produtos da evolução de voçorocas, como o fenômeno de piping, que consiste na geração natural de cavidades no solo. O contraste de resistividade elétrica entre o solo e o espaço vazio da cavidade possibilitam o uso do método da Eletrorresistividade neste tipo de estudo. Este método foi utilizado na investigação de uma voçoroca no município de São Pedro (SP), para a avaliação da continuidade de cavidades formadas por processos de erosão interna ou piping. Foram realizadas 6 linhas paralelas de imageamento elétrico para medidas de resistividade elétrica, com espaçamento de 1m entre eletrodos, de 5m entre linhas, por meio do arranjo Wenner-Schlumberger. A correlação entre dados geofísicos e cavidades revelou uma assinatura geoelétrica de alta resistividade, possivelmente devido à ausência de preenchimento. A integração lateral das seções em mapas de isovalores para a profundidade de ocorrência das cavidades, revela o prolongamento e a ramificação de pipings em porções mais internas do terreno. / Unorganized urban expansion can result in several consequences to the environment. The absense of planning in the flow of rain water, allied with low cohesion in some terrains can generate gullies, which growing can offer geotechnical risks for the population. By this case, geophysics allows the diagnostic of some products from gully erosion, like the piping phenomena, where natural cavities are formed in the subsoil.The Electrical resistivity contrasts from the soil and the cavities filling material allows the application of Electrorresistivity method. The method was applied in a gully in São Pedro (SP) county to detect cavities formed in a process denominated internal erosion or piping. Were used 6 parallel lines of electrical imaging for the measurement of electrical resistivity values with 84 electrodes and spacing of 1m between each one, 5m between each acquisition line, by the Wenner-Schlumberger array. The results show high resistivity assignature probably due to the absence of filling in the cavities. The lateral integration of the sections in a isovalues map to the depth where occurs the cavities reveals the length and ramifications of the pipings in the internal portions of the terrain.

Nas plantas industriais dos setores químico e petroquímico observa-se uma grande quantidade de complexas redes de tubulações instaladas, o que se deve basicamente à necessidade de transferir e processar fluídos em diversas condições de pressão e temperatura em suas operações produtivas. Uma indústria petroquímica de médio porte possui entre 3.000 e 15.000 toneladas de tubulações de aço-carbono instaladas, fazendo com que o adequado dimensionamento desse sistema de tubulações adquira grande importância. Este trabalho caracteriza os principais componentes, materiais, condições de projeto e critérios normativos existentes, em especial sob temperaturas elevadas. Realiza uma avaliação comparativa dos métodos de solução estrutural dessas tubulações e analisa criticamente algumas das premissas originais que ainda orientam o seu dimensionamento, visando uma melhor adequação destas. Por fim, juntamente com um estudo de caso, apresenta uma proposta de metodologia de dimensionamento, aplicando o Método dos Elementos Finitos, com o objetivo de aliar mais segurança, otimizar a construção e permitir um projeto mais econômico, diante das grandes quantidades de material envolvidas nessas instalações. / In the chemical and petrochemical plants we can notice a big amount and complexity of pipings installeds, it happens due to the need to transfer and process fluids with differents pressures and temperatures and to get the operational requirements of production. A middle size petrochemical plant has among 3,000 to 15,000 tons of carbon steel pipings assembled so an adjusted sizing of these piping systems is very important. This study presents the main components, materials, design features and existing code procedures, especially under higher temperatures. It makes a comparative valuation about methods of structural solution to pipings and discussing previous concepts applied in the codes to improve these applications. In also, together a case study, presents a proposal of a methodology to sizing of pipings using Finity Element Analyse, with the goal to get a solution more safety, optimized and an economic project, in front of the large quantity of material involved in these installations.

Orientador: Sérgio Nascimento Bordalo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-23T18:52:37Z (GMT). No. of bitstreams: 1 Tochetto_LuanGregori_M.pdf: 7430018 bytes, checksum: 8523efb2c0601ab21d1e2057f0d7c2af (MD5) Previous issue date: 2013 / Resumo: Tubulações submarinas, tais como risers e jumpers, sofrem carregamentos estáticos e dinâmicos devido a forças ambientais, correntes marítimas e ondas, carregamentos devido aos deslocamentos da unidade flutuante de produção (plataformas ou navios), escoamento interno, além de outras causas. O controle dos deslocamentos oscilatórios dessas tubulações é fundamental para a confiabilidade e vida em fadiga desses sistemas, motivando projetos de pesquisa com tal propósito nos últimos anos. Uma tecnologia em consideração é o Pounding Tuned Mass Damper (PTMD), o qual é o assunto do presente trabalho. Este trabalho apresenta um estudo experimental de um absorvedor de vibrações - o PTMD - acoplado a um modelo de jumper submarino em escala reduzida. O aparato é composto de uma seção de tubo montada em um sistema de suspensão elástica para movimento em duas direções, propiciando similaridade dinâmica parcial entre o protótipo e o modelo. O modelo de PTMD é um sistema massa - mola anexado, similar a um supressor tuned mass damper (TMD), a não ser a adição de um envoltório de batimento, o qual limita o deslocamento da massa do PTMD, dissipando energia do tubo oscilante através do impacto da massa do PTMD contra esse envoltório. Experimentos de oscilação livre e forçada foram realizados na direção vertical, no seco e na água. Os resultados obtidos de amplitude versus frequência foram utilização para determinar a eficácia do absorvedor quando comparado com sua operação a seco. Os resultados deste trabalho são os primeiros passos no desenvolvimento de um dispositivo aplicável a uma real tubulação submarina de petróleo. Os dados adquiridos neste trabalho foram empregados na melhoria e desenvolvimento de um modelo numérico do sistema tubo - PTMD para um simulador computacional / Abstract: Submarine pipelines, such as jumpers and risers, suffer static and dynamic loads due to environmental forces - currents and waves, to the displacements of floating production units (platforms or ships) and to the internal flow, among other causes. Controlling the oscillatory displacements of the pipelines is critical to the reliability and fatigue of these systems, motivating research projects to deal with such issues in the past few years. One technology under consideration is the Pounding Tuned Mass Damper (PTMD), which is the subject of the present work. The current work presents an experimental study of a vibration suppressor - the PTMD - attached to a scaled down submarine jumper model. The apparatus is composed of a test pipe section mounted on an elastic suspension harness for two directions of motion, providing partial dynamic similarity between the prototype and the model. The PTMD model is a lumped mass-spring attachment similar to a tuned mass dumper (TMD) suppressor, but with the addition of a pounding layer, which limits the motion of the PTMD mass, dissipating the energy of the oscillating pipe through the impact of the PTMD mass against that layer. So far, free and forced oscillation experiments were executed, in the vertical direction. The tests were conducted in a water tank, where comparisons of amplitude versus frequency were made to determine the suppressor effectiveness, on air and underwater. The results of this work are the preliminary step on the development of a device applicable to an actual petroleum submarine pipeline. The data gathered from this work was employed in the improvement of a numerical model of the pipe-PTMD system for a computer simulator / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo

This study examines to what extent preposition stranding is used in connection with which, whom and who in three different UK papers. Also what factors influence the use of preposition stranding has been studied. The hypothesis that pied-piping is more common than preposition stranding has been confirmed. A factor that has a certain influence on the use of preposition stranding is the style of the paper. The more formal of the papers studied, The Times, did not use preposition stranding to the same extent as the other two, The Sun and Today. The subject domain of the texts has influence on the use of preposition stranding, with more informal domains such as sports and miscellaneous (e.g. gossip) using stranding to a higher extent than the other domains, e.g. business, politics and culture. The prepositions themselves also influence the use of preposition stranding with some prepositions, such as on, with, for and into, that are likely to appear stranded and others, such as in that are likely to appear pied-piped.

Seepage-related erosion is one of the predominant mechanisms responsible for incidents and failures of dams and levees. Current geotechnical engineering practice consists of comparing expected exit gradients with the critical gradient of the soil at the seepage exit point. The critical gradient is generally considered as the ratio of soil buoyant unit weight and the unit weight of water, suggesting that the critical gradient only depends on the void ratio and specific gravity of the solids. However, in the field and in research, it has been observed that piping can initiate at average gradients much lower than unity due to concentrations in flow and non-vertical exit faces. Therefore, there is a need for deeper understanding of the granular scale mechanisms of the piping erosion process. This thesis presents the results of a laboratory study to assess the effects that soil properties and exit face configurations have on the potential for initiation of piping and the piping mechanisms. By using a laboratory device designed and constructed specifically for this study, the critical gradients needed to initiate piping in a variety of sandy soils were measured to assess the effects that parameters such as gradation, grain size, and grain shape have on the critical gradients. The tests are also used to observe the grain scale mechanisms of piping erosion initiation. The ultimate goal of the study is to develop an empirical, but mechanism-based, grain-scale model that can take into account the effects of converging flows, non-horizontal exit faces, and soil properties while assessing the potential for piping erosion to occur.

Sweden is generally considered to be a low seismicity area, but for structures within nuclear power facilities, the safety level demand with respect to seismic events are high and thus, these structures are required to be earthquake-resistant. The seismic hazard is here primarily considered to be associated with near-field earthquakes. The nuclear power plants are further founded on hard rock and the expected ground motions are dominated by high frequencies. The design earthquake considered for the nuclear facilities has an annual probability of 10-5 events, that is, the probability of occurrence is once per 100 000 years. The focus of the study is the seismic response of large concrete structures for the nuclear power industry, with regard not only to the structure itself but also to non-structural components attached to the primary structure, and with emphasis on Swedish conditions. The aim of this licentiate thesis is to summarize and demonstrate some important aspects when the seismic load is dominated by high frequencies. Additionally, an overview of laws, regulations, codes, standards, and guidelines important for seismic analysis and design of nuclear power structures is provided. The thesis includes two case studies investigating the effect of seismic high-frequency content loads. The first study investigates the influence of gaps in the piping supports on the response of a steel piping system subjected to a seismic load dominated by high amplitudes at high frequencies. The gaps are found in the joints of the strut supports or are gaps between the rigid box supports and the pipe. The piping system is assessed to be susceptible to high-frequency loads and is located within the reactor containment building of a nuclear power plant. The stress response of the pipe and the acceleration response of the valves are evaluated. The second study investigates the effect of fluid-structure interaction (FSI) on the response of an elevated rectangular water-containing concrete pool subjected to a seismic load with dominating low and high frequencies, respectively. The pool is located within the reactor containment building of a boiling water reactor at a nuclear power plant. The hydrodynamic pressure distribution is evaluated together with the stress distribution in the walls of the tank. From the two case studies, it is evident that the response due to a seismic load dominated by high frequencies and low frequencies, respectively, is different. Although the seismic high-frequency load may be considered non-damaging for the structure, the effect may not be negligible for non-structural components attached to the primary structure. Including geometrical non-linear effects such as gaps may however reduce the response. It was shown that the stress response for most of the pipe elements in the first case study was reduced due to the gaps. It may also be that the inclusion of fluid-structure interaction effects changes the dynamic properties of a structural system so that it responds significantly in the high frequency range, thus making it more vulnerable to seismic loads dominated by high frequencies. In the second case study, it was shown that even for a seismic load with small amplitudes and short duration, but with dominating high-frequency content, as the Swedish 10-5 design earthquake, the increase of the dynamic response as fluid-structure interaction is accounted for is significant. / <p>QC 20150519</p>

The digitization of graph-based engineering diagrams like P&IDs or circuit drawings from optical sources as well as their subsequent processing involves both image understanding and semantic technologies. More precisely, after a raw graph has been obtained by an object detection and line extraction pipeline, semantic gaps (like resolving material flow directions) need to be overcome to retain a comprehensive, semantically correct graph. Likewise, the graph representation often needs to be altered to achieve interoperability with established CAE systems and to accommodate customer-specific requirements. Semantic technologies provide powerful tools to manipulate such data but usually require rather complicated implementation. Graphically presentable graph based rules provide a code-free mean to ease the interaction with domain experts. In order to be applicable in real-world applications, both geometric and computational aspects need to be considered. This paper explores these aspects and demonstrates use cases of such rule graphs.

Red foxes (Vulpes vulpes) have been identified as a key predator of the threatened piping plover (Charadrius melodus) along the U.S. Atlantic coast. However, little is known about coastal red fox ecology, making it difficult to create effective red fox management strategies in these settings. Here, we quantify aspects of red fox population, spatial, and dietary ecology and interactions with threatened piping plovers on Fire Island, New York. We conducted remote camera surveys, scat and sign surveys, den monitoring, and GPS tracking of red foxes on the island in 2015–2018. We used these data to estimate red fox occupancy, reproduction, survival, and population density. We used GPS data to investigate red fox space use, habitat selection, and responses to piping plover nest exclosure setup, pre-hatch pipping, and hatching. We used fecal dietary analyses and data from den prey item surveys to quantify the frequency of piping plover predation and to identify major prey items of red foxes on the island. Red fox occupancy remained high even after substantial decreases in abundance, population density, annual reproduction, and seasonal survival following 2 sarcoptic mange outbreaks. Within their home ranges, red foxes selected areas that were closer to vegetation during the daytime and twilight hours, but farther from vegetation at night. We did not find clear evidence that red foxes in our study area keyed in on piping plover nest exclosure setup, pipping, or hatching at the spatial scales considered in our comparisons, although fox penetration of and digging at exclosures was an issue in 2015 at Smith Point County Park. Items from Orders Rodentia (rodents, 43% of scats), Coleoptera (beetles, 38%), and Decapoda (crabs and other crustaceans, 29%) were most frequently found in 293 red fox scats examined. Skates (Family Rajidae, 89% of dens with food items) and Atlantic surf clams (Spisula solidissima, 67%) were found most frequently outside of dens. We did not find any identifiable piping plover remains in red fox scats or outside of dens. Our results suggest that direct interactions between red foxes and piping plovers during our study period and in our study area were less frequent than expected, but concurrent work by collaborators documented that the trap success of red foxes was negatively related to piping plover reproductive output during our study period. Lethal removal of red foxes is unlikely to eliminate them from shorebird nesting areas unless complete eradication of foxes from the island can be achieved. We recommend strategic vegetation management in and around piping plover nesting areas to reduce daytime resting areas and hunting cover for red foxes, and continued use of nest exclosures. We also recommend further investigation into indirect impacts of red foxes on piping plover populations, and into the possibility that anthropogenic food resources could be subsidizing the island's red fox population. / Doctor of Philosophy / Red foxes have been identified as a key predator of the piping plover, a small migratory shorebird that breeds along the U.S. Atlantic coast and is considered 'threatened' (at risk of becoming endangered and eventually disappearing) within the United States. The lack of information about red fox ecology in coastal settings has been a challenge for wildlife biologists tasked with reducing predation on piping plovers. We investigated red fox ecology, behavior, and interactions with piping plovers on Fire Island, New York. We used trail cameras, collected scat (feces), monitored dens, and tracked red foxes on the island with global positioning system (GPS) collars in 2015–2018. We used these data to estimate red fox distribution, litter sizes, survival rates, and population sizes. We used GPS data to estimate red fox territory sizes, describe habitat selection, and investigate responses to piping plover nest exclosure setup, pipping (a period before hatching during which chicks vocalize inside the eggs), and hatching. We dissected red fox scats and recorded prey items found outside of dens to determine what red foxes on the island were eating. The proportion of each study area used by red foxes remained high even after substantial decreases in abundance, population density, annual reproduction, and seasonal survival following 2 parasitic disease (sarcoptic mange) outbreaks. Within their territories, red foxes selected areas that were closer to vegetation during the daytime and twilight hours but farther from vegetation at night. We did not find clear evidence that red foxes in our study area keyed in on piping plover nest exclosure setup, pipping, or hatching, although fox penetration of and digging at exclosures was an issue in some years at a site not included in those comparisons. Rodents, beetles, and crustacean remains were found most frequently in red fox scats. Skates and surf clams were found most frequently outside of dens. We did not find any identifiable piping plover remains in red fox scats or outside of dens. Our results suggest that that direct interactions between red foxes and piping plovers may be less frequent than previously believed, but concurrent work by collaborators documented that the trap success of red foxes was negatively related to piping plover reproductive output during our study period. Lethal removal of red foxes is unlikely to eliminate red foxes from shorebird nesting areas unless all foxes on the island are removed. We recommend strategic vegetation removal in and around piping plover nesting areas to reduce daytime resting spots and hunting cover for red foxes, and continued use of nest exclosures. We also recommend further investigation into indirect impacts of red foxes on piping plover populations, and into the possibility that anthropogenic food resources could be subsidizing the island's red fox population.

Prairie rivers of the Great Plains, USA, provide important habitat for the federally threatened piping plover (“plover”, Charadrius melodus). Plovers nest on open to sparsely vegetated river sandbars, and their demographic rates are closely linked to habitat availability and quality, as well as river flow. The Niobrara River in northern Nebraska has supported 22–41% of the state’s plovers since species listing in 1986, but the population and habitat are relatively understudied, and both have declined since 2010. The objectives of this study were to understand plover demography, habitat, and the role of the Niobrara in the regional plover population. Periods of high river flow promote creation and maintenance of suitable sandbar nesting habitat, but increased river flow during the plover breeding season can decrease nest and chick survival. We estimated the effect of daily peak river flow on survival rates of 115 nests and 66 chicks on the Niobrara River, 2010–2016, using logistic exposure and Cormack-Jolly-Seber models, respectively. We monitored 1,874 banded hatch-year and adult birds across the regional population (Niobrara River, Lewis and Clark Lake, Gavins Point Reach segment of the Missouri River), and used multi-state mark-recapture models to estimate survival and inter-annual dispersal probabilities among sites relative to habitat availability. We developed land cover datasets from high-resolution aerial imagery to quantify suitable habitat and compare the relative effects of habitat characteristics on nest-site selection and nest success for a subset of years (2010, 2012, 2014, and 2016) using logistic regression models. We included data from a sympatric nester with similar nesting habitat needs, the interior least tern (“tern”, Sternula antillarum athalassos), to improve precision of our models. We compared 63 plover and 92 tern nests to 292 random unused points, and 73 successful (hatched ≥1 egg) to 79 failed nests. Low nest and chick survival and high emigration from the Niobrara appear to be important factors contributing to population decline. Daily nest and chick survival were negatively related to river flow. Nest-site selection was based primarily on distance to the river bank (i.e., the nearest potential source of predators), yet flooding (eggs submerged or washed out of the nest bowl during increased river flow) caused at least as many nest failures as predation. Nests predominantly were surrounded by dry sand habitat, indicating some degree of flood avoidance, but were no farther from water than random, and drier nest sites were no less likely to fail. Dispersal occurred throughout the regional population, but plovers were more likely to leave the Niobrara than to enter it. Expansive flood-created sandbars on the Missouri River, concurrent with a trend towards more vegetated and saturated habitat on the Niobrara, may have drawn birds from the Niobrara population, especially those that dispersed to the Niobrara during sustained Missouri River flooding 2010–2011. The outsized negative effect of flooding on nest success, the lack of protection afforded by dry sand nest sites, and selection for nesting habitat based more strongly on predator avoidance than flood avoidance suggest that plovers may have face more frequent and intense levels of breeding season flooding than is typical. Identifying and promoting the processes that contribute to creation and maintenance of high-elevation sandbars on the Niobrara is an important next step towards effective management of nesting birds. / Master of Science