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11	Vibroacoustic Analysis of an OLTC Diverter Switch for Condition Monitoring : Time frequency analysis with Fourier and wavelet transform in combination with multivariate logistic regression for condition monitoring of OLTC diverter switch Persson, Simon January 2023 (has links) Vibrations are everywhere around us all the time and we often recognise them as sounds that we can hear and analyse with our brain. In this thesis, data that has been gathered from a diverter switch (DS) in a controlled environment, is analysed. This data consists of vibroacoustic measurements and information to indicate what is happening inside the DS as the vibroacoustic data is gathered. The frequency properties of vibroacoustic data from the DS gathered before this thesis are displayed using a wavelet transformation model. This means the frequency properties of the signal can be approximated for all times in the operation with a certain accuracy. As the DS is built from many different components, the frequency properties of these components are compared to the time-frequency picture of the full DS operation. This sort of comparison ends up not being feasible as the complexity of the DS frequency pattern is much more than that of a sum of its component’s frequency pattern. A second approach of analysing the gathered vibroacoustic data is by using a classification model. The information about what is happening inside of the DS is used to train a logistic regression model on different defined regions of the vibroacoustic data. Before the training is preformed though, the different defined regions are transformed into frequency space with help of the fast Fourier transform. With this, a classification model is produced, where vibroacoustic data of any time region can be fed into the model and the model will classify which defined region this vibroacoustic data belongs to. The results are promising, and the model can be used both for classification of the defined regions and potentially used to determine if the vibroacoustic properties of the DS has changed due to wear of the mechanical components or transformer oil. Wavelet transform CWT logistic regression machine learning ML vibroacoustic analysis time frequency analysis tap changer diverter switch power transformer classification prediction condition vibrations state prediction Hitachi Energy Computer and Information Sciences Data- och informationsvetenskap
12	[pt] A CONTRIBUIÇÃO DE DERIVADORES OCEÂNICOS E SIMULAÇÕES NUMÉRICAS DE CORRENTES MARINHAS E VENTOS EM APOIO AO PLANEJAMENTO TERRITORIAL: O CASO DA BAÍA DE GUANABARA / [en] THE CONTRIBUTION OF OCEAN DRIFTERS AND NUMERICAL SIMULATIONS OF OCEAN CURRENTS AND WINDS IN SUPPORT OF THE TERRITORIAL PLANNING: THE CASE OF GUANABARA BAY FLÁVIA ADISSI 11 October 2016 (has links) [pt] Este trabalho aborda a questão da movimentação e acúmulo do lixo flutuante na Baía de Guanabara e contextualiza a problemática da poluição da Baía e seu entorno a partir de diversos temas inter-relacionados, como: o uso dos derivadores e a sua analogia com o lixo flutuante; a existência de projetos que têm ajudado no rastreamento do lixo flutuante na Baía a partir do mapeamento de correntes superficiais e ventos; o saneamento da bacia hidrográfica da Baía, a qualidade da água de seus afluentes e a análise da população que reside no seu entorno; o entendimento de uma visão mais humanista e ecológica no redesenho das cidades e também programas internacionais de revitalização de corpos d água degradados. Dentro deste contexto, são feitas reflexões e análises integradas a partir de uma modelagem da probabilidade de transporte de resíduos da Baía e da paisagem encontrada em seu entorno, através da utilização de produtos cartográficos. Tais análises consideram os dados levantados nos quatro mapas que são apresentados, de forma a prover uma visão mais ampla e integrada do espelho d água e também do entorno da Baía. O objetivo deste trabalho foi entender como o espaço territorial e a ocupação urbana do entorno da Baía podem impactar a poluição do espelho d água da Baía e por ela serem impactados de forma a contribuir com programas de despoluição. Foi feito então um recorte em quatro regiões e realizada uma análise integrada para cada, de forma a prover um melhor entendimento a partir da exemplificação. A análise integrada proporciona uma visão mais abrangente da questão da poluição, auxiliando os gestores dos programas de despoluição a encontrarem relevantes informações para priorizar as ações a serem tomadas. / [en] This work approaches the issue of the movement and accumulation of floating litter in the Guanabara Bay, in Rio de Janeiro, Brazil. It contextualizes the problem of the pollution in the Bay and surroundings, and it does so from several different interrelated issues, such as the use of ocean drifters and their analogy with the floating litter; the existence of projects that have been helping in the tracking of the floating litter in the Bay from the mapping of the surface currents and the winds; the sanitation efforts in the hydrographic basin of the Bay; the quality of the water in the rivers that debouch into the Bay and a better understanding of the population that live in the area; the necessity of a more humanistic and ecological view in the planning of those cities; and also international programs to revitalize degraded water bodies. One of the objectives of this dissertation is to understand how the territorial space and the urban occupation of the Bay s surroundings can impact the pollution in the Bay and be impacted by that pollution. So the entire region was divided in four areas and an integrated analysis was made for each area so that a better understanding could be provided by exemplification. Such integrated analysis provides a more comprehensive view of the pollution problem and helps the depollution program officers to find relevant information and better prioritize actions. The Guanabara Bay plays a strategic role not only around the towns and cities that are part of its hydrographic basins, but in the whole state of Rio de Janeiro and also the entire country. It is one of the most important marine ecosystems from the social, economic and environmental points of view. It is located in the Rio de Janeiro city metropolitan area, with the Brazilian coast s largest population concentration (about 10 million people, or 80 percent of the state s population). A national security area, the Bay shelters two naval bases, one navy shipyard, the Rio de Janeiro Port (the second largest in the country, with more than 2 thousand ship moorings annually), two airports (Antonio Carlos Jobim, and Santos Dumont), and other shipyards and marinas. The Guanabara Bay is also way for innumerous cargo and passenger ferryboats, fishing boats, and other boats for leisure and tourism. The water in the Bay is also used for water sports and aquaculture (fish farming). (KJERFVE, 1997; BERGAMO, 2006 apud CARVALHO, 2011). [pt] MODELAGEM NUMERICA [pt] OCUPACAO URBANA [pt] DERIVADOR [pt] LIXO FLUTUANTE [pt] MAPEAMENTO [pt] BAIA DE GUANABARA [pt] POLUICAO [en] NUMERICAL MODELING [en] URBAN OCCUPATION [en] DIVERTER [en] FLOATING LITTER [en] MAPPING [en] GUANABARA BAY [en] POLLUTION
13	Advanced materials for plasma facing components in fusion devices Thomas, Gareth James January 2009 (has links) This thesis describes the design, manufacture and characterisation of thick vacuum plasma sprayed tungsten (W) coatings on steel substrates. Fusion is a potentially clean, sustainable, energy source in which nuclear energy is generated via the release of internal energy from nuclei. In order to fuse nuclei the Coulomb barrier must be breached - requiring extreme temperatures or pressures – akin to creating a ‘star in a box’. Tungsten is a promising candidate material for future fusion reactors due to a high sputtering threshold and melting temperature. However, the large coefficient of thermal expansion mismatch with reactor structural steels such as the low activation steel Eurofer’97 is a major manufacturing and in-service problem. A vacuum plasma spraying approach for the manufacture of tungsten and tungsten/steel graded coatings has been developed successfully. The use of graded coatings and highly textured 3D interface surfi-sculpt substrates has been investigated to allow the deposition of thick plasma sprayed tungsten coatings on steel substrates. Finite element models have been developed to understand the residual stresses that develop in W/steel systems and made use of experimental measurements of coating thermal history during manufacture and elastic moduli measured by nano-indentation. For both the graded and surfi-sculpt coating, the models have been used to understand the mechanism of residual stress redistribution and relief in comparison with simple W on steel coatings, particularly by consideration of stored strain energy. In the case of surfi-sculpt W coatings, the patterned substrate gave rise to regular stress concentrating features, and allowed 2mm thick W coatings to be produced reproducibly without delamination. Preliminary through thickness residual stress measurements were compared to model predictions and provided tentative evidence of significant W coating stress relief by regulated coating segmentation. 621.48
14	Avledning av öringsmolt (<em>Salmo trutta</em>) från turbinintag / Diversion of trout smolts (<em>Salmo trutta)</em> from turbine intakes Engqvist, Thérèse January 2009 (has links) <p>Vattenkraftstationer, med dammar och turbiner, utgör hinder för nedströmsvandrande smolt. Syftet med denna studie var att undersöka turbindödligheten för öringsmolt (<em>Salmo trutta)</em> vid två kraftstationer, de befintliga ytlänsarnas avledningseffekt och om effekten kunde förstärkas genom mörkläggning i form av övertäckning av kraftkanalen med en presenning vid turbinintaget. Utöver detta var avsikten även att undersöka om det fanns något samband mellan smoltgrad och smoltens förmåga att förflytta sig mot havet. I Emån i Småland fångades 46 öringsmolt som radiomärktes och sattes ut vid två kraftstationer och pejlades dagligen i sex veckor. Det var en större dödlighet vid den övre stationen än vid den nedre. Ytlänsen vid den nedre stationen hade en klart avledande effekt, men inte ytlänsen vid den övre stationen. Samtliga smolt som valde passage via isutskovet, gjorde det när kraftkanalen vid turbinintaget var övertäckt med presenning (d.v.s. ljusintensiteten minskades kraftigt). Det gick inte att påvisa någon skillnad mellan låg och hög smoltgrad eller tidig och sen utsättning för fördröjning vid den ena kraftstationen, inte heller för förflyttning efter de två kraftstationerna.</p> / <p>Hydropower plants, with dams and turbines, form obstacles to smolts migrating downstream. The purpose of this study was to investigate turbine-induced mortality of brown trout (<em>Salmo trutta</em>) smolts at two power plants, guidance efficiency of existing diverters and whether the effect was enhanced by reducing light levels at the turbine intake by covering the power plant channel with an opaque tarpaulin. Furthermore, the aim was to investigate whether there was a relationship between smolt status and the smolts’ ability to move towards the sea. In the River Emån in Småland 46 trout smolts were caught, radio-tagged, released at two power plants and tracked daily for six weeks. There was a higher mortality at the upper power plant than at the lower one. The diverter at the lower power plant had a statistically significant guiding effect, but the diverter at the upper power plant did not. All of the smolts that chose passage through the trash gate did so when the power channel was covered with tarpaulin (i.e. light levels were greatly reduced). There was no evidence that smolt status or release date would affect passage times at the upper station, nor did smolt status affect swimming speeds downstream of the two power stations.</p> / Cost-Benefit Analysis of River Regulation diversion smolt smolts trout telemetry radiotelemetry migration mortality hydropower turbine turbines trash gate Salmo trutta regulated river turbine-induced mortality power station power stations diverter diverters smolt status light manipulation downstream migration wolf trap trap cover opaque tarpaulin migration problems radio tag avledning smolt öring Emån Finsjö pejling reglerat vattendrag telemetri radiotelemetri radiomärkning vandring dödlighet mortalitet migration vattenkraft turbin turbiner isutskov Salmo trutta vandringshinder turbindödlighet kraftstation kraftstationer ytläns ytlänsar smoltgrad smoltstatus ljusmanipulation nedströmsvandring träfälla fälla radiosändare övertäckning presenning mörkläggning Biology Biologi
15	Avledning av öringsmolt (Salmo trutta) från turbinintag / Diversion of trout smolts (Salmo trutta) from turbine intakes Engqvist, Thérèse January 2009 (has links) Vattenkraftstationer, med dammar och turbiner, utgör hinder för nedströmsvandrande smolt. Syftet med denna studie var att undersöka turbindödligheten för öringsmolt (Salmo trutta) vid två kraftstationer, de befintliga ytlänsarnas avledningseffekt och om effekten kunde förstärkas genom mörkläggning i form av övertäckning av kraftkanalen med en presenning vid turbinintaget. Utöver detta var avsikten även att undersöka om det fanns något samband mellan smoltgrad och smoltens förmåga att förflytta sig mot havet. I Emån i Småland fångades 46 öringsmolt som radiomärktes och sattes ut vid två kraftstationer och pejlades dagligen i sex veckor. Det var en större dödlighet vid den övre stationen än vid den nedre. Ytlänsen vid den nedre stationen hade en klart avledande effekt, men inte ytlänsen vid den övre stationen. Samtliga smolt som valde passage via isutskovet, gjorde det när kraftkanalen vid turbinintaget var övertäckt med presenning (d.v.s. ljusintensiteten minskades kraftigt). Det gick inte att påvisa någon skillnad mellan låg och hög smoltgrad eller tidig och sen utsättning för fördröjning vid den ena kraftstationen, inte heller för förflyttning efter de två kraftstationerna. / Hydropower plants, with dams and turbines, form obstacles to smolts migrating downstream. The purpose of this study was to investigate turbine-induced mortality of brown trout (Salmo trutta) smolts at two power plants, guidance efficiency of existing diverters and whether the effect was enhanced by reducing light levels at the turbine intake by covering the power plant channel with an opaque tarpaulin. Furthermore, the aim was to investigate whether there was a relationship between smolt status and the smolts’ ability to move towards the sea. In the River Emån in Småland 46 trout smolts were caught, radio-tagged, released at two power plants and tracked daily for six weeks. There was a higher mortality at the upper power plant than at the lower one. The diverter at the lower power plant had a statistically significant guiding effect, but the diverter at the upper power plant did not. All of the smolts that chose passage through the trash gate did so when the power channel was covered with tarpaulin (i.e. light levels were greatly reduced). There was no evidence that smolt status or release date would affect passage times at the upper station, nor did smolt status affect swimming speeds downstream of the two power stations. / Cost-Benefit Analysis of River Regulation diversion smolt smolts trout telemetry radiotelemetry migration mortality hydropower turbine turbines trash gate Salmo trutta regulated river turbine-induced mortality power station power stations diverter diverters smolt status light manipulation downstream migration wolf trap trap cover opaque tarpaulin migration problems radio tag avledning smolt öring Emån Finsjö pejling reglerat vattendrag telemetri radiotelemetri radiomärkning vandring dödlighet mortalitet migration vattenkraft turbin turbiner isutskov Salmo trutta vandringshinder turbindödlighet kraftstation kraftstationer ytläns ytlänsar smoltgrad smoltstatus ljusmanipulation nedströmsvandring träfälla fälla radiosändare övertäckning presenning mörkläggning Biology Biologi

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