Dissolved Gas Analysis
Mostrando 1-12 de 17 artigos, teses e dissertações.
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1. SIMULATION OF THERMAL DECOMPOSITION OF MINERAL INSULATING OIL
Abstract Dissolved gas analysis (DGA) has been applied for decades as the main predictive maintenance technique for diagnosing incipient faults in power transformers since the decomposition of the mineral insulating oil (MIO) produces gases that remain dissolved in the liquid phase. Nevertheless, the most known diagnostic methods are based on findings of sim
Braz. J. Chem. Eng.. Publicado em: 2015-09
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2. IDENTIFICAÇÃO DE COMPOSTOS ORGÂNICOS EM LIXIVIADO DE ATERRO SANITÁRIO MUNICIPAL POR CROMATOGRAFIA GASOSA ACOPLADA A ESPECTROMETRIA DE MASSAS
The organic compounds present in leachate can contaminate soil, superficial and underground water, and the majority is considered harmful to the environment and human health. The objective of this study was to identify organic compounds present in landfill leachate located in Maringá-PR by gas chromatography coupled to mass spectrometry (GC-MS). The raw
Quím. Nova. Publicado em: 2015-07
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3. DIAGNOSIS OF FAULTS IN POWER TRANSFORMERS USING SEMICONDUCTOR GAS SENSORS. / DIAGNÓSTICO DE FALHAS EM TRANSFORMADORES DE POTÊNCIA UTILIZANDO SENSORES DE GAS SEMICONDUTORES.
Esta dissertação introduz o estudo do uso de uma matriz de sensores de gases de dióxido de estanho na detecção de falhas em transformadores de potência, através dos gases dissolvidos no óleo. O objetivo desta pesquisa é analisar os dados obtidos pelos sensores de gás, utilizando algumas técnicas de reconhecimento de padrão, e desta forma, verific
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/08/2012
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4. Comparação entre os critérios de diagnósticos por análise cromatográfica de gases dissolvidos em óleo isolante de transformador de potência / Comparison between the diagnostic criteria for chromatographic analysis of gases dissolved in insulating oil for transformer
Existem inúmeras ferramentas e metodologias para o diagnóstico de falhas em transformadores de potência, tanto para a monitoração e acompanhamento do equipamento em operação (planta fixa) como àquele retirado e abrigado em laboratórios de unidades fabris. Em função dos custos envolvidos no transporte dos equipamentos, manuseio para a substituiçã
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/04/2012
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5. Monitoramento on-line e DiagnÃstico Inteligente da Qualidade DielÃtrica do Isolamento LÃquido de Transformadores de PotÃncia / On-line monitoring and intelligent diagnosis of dielectric quality of liquid isolation of power transformers.
O monitoramento e o diagnÃstico de falhas incipientes em transformadores de potÃncia imersos em Ãleo estÃo diretamente relacionados à avaliaÃÃo das condiÃÃes do sistema de isolamento. Neste estudo, estabelece-se o conceito de monitoramento e diagnÃstico, e em seguida tÃcnicas de monitoramento on-line sÃo discutidas. Um sistema de prÃ-diagnÃstic
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/03/2012
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6. Concentrações de randônio nas águas subterrâneas, rochas e solos de Porto Alegre, RS
Many water-supply systems in Brazil utilize groundwaters at least as part of their networks. This is the case of Porto Alegre, capital of Rio Grande do Sul State, whose population is about 1.4 million inhabitants. However, there is little present knowledge in Brazil of the factors affecting Rn presence in the water supplied for end-users, despite the economi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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7. DETERMINATION OF TOTAL AS IN OCEANIC WATER BY HG AFS / DETERMINAÇÃO DE AS TOTAL EM ÁGUAS OCEÂNICAS POR HG AFS
The increase in industrial activity has increased human exposure to metals and metalloids exponentially. In this context, arsenium is a good example, being increasingly found in several natural environments. It is an element with no essential biological function, and possessed of elevated toxicity. The discharge of toxic elements in aquatic bodies can promot
Publicado em: 2010
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8. Concentration fields near air-water interfaces during interfacial mass transport: oxygen transport and random square wave analysis
Mass transfer across a gas-liquid interface was studied theoretically and experimentally, using transfer of oxygen into water as the gas-liquid system. The experimental results support the conclusions of a theoretical description of the concentration field that uses random square waves approximations. The effect of diffusion over the concentration records wa
Brazilian Journal of Chemical Engineering. Publicado em: 2009-09
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9. DIAGNÓSTICO DE FALHAS INCIPIENTES EM TRANSFORMADORES DE POTÊNCIA UTILIZANDO A TEORIA DA EXTENSÃO / FAULT INCIPIENT DIAGNOSIS IN POWER TRANSFORMERS USING EXTENSION THEORY
Power transformers play an important role in the power energy supply, demanding the continuous monitoring of process that could lead to operation faults, specifically in the equipment electric insulation. Methods considered in the standards IEC, IEEE and NBR7274 for dissolved gas analysis (DGA) do not provide good levels of accuracy, because there are scenar
Publicado em: 2008
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10. Processos redoxes de ferro em argilominerais: caracterização, métodos de quantificação, especiação e modificações estruturais
Redox processes within clays and clay minerals influence significantly in different physical and chemical properties in soils and sediments, mainly which ones related to the chemical interaction between solid and solution phases (liquid or gas) such as superficial charge and ion dynamics. Other, like expansibility, water retention capacity, surface area, and
Publicado em: 2007
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11. Atmospheric particulate matter in the city of São carlos-SP: quantification and source indentification. / Material particulado atmosférico na cidade de São Carlos- SP: quantificação e identificação de fontes.
In the present work, breathable particulate matter (PM10) concentration was measured in their fine (PM2.5-10) and ultra-fine (MP2.5) fractions, in the municipal district of São Carlos. The samplings were carried out from 2001 to 2004 for PM10 (complemented with data from 1997 to 2001 taken from the research group databank) and for the period of 1 year (2001
Publicado em: 2005
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12. Method for measuring dissolved hydrogen in anaerobic ecosystems: application to the rumen.
A method of transferring dissolved H2 to a CO2 headspace and then absorbing out the CO2 to concentrate the H2 before gas chromatographic analysis was developed to measure low concentrations of dissolved H2. A detection limit of 10 pmol of H2 ml-1 of water was achieved. When used ot monitor H2 changes in a bovine rumen, a 10-fold increase in H2 was noted 1 h