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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1021

Estudo do comportamento hidráulico de mistura solo-bentonita visando alternativa de emprego como sistema de proteção para aterros sanitários / Study of the hydraulic behavior of soil-bentonite mixture seeking employment as protection system for sanitary landfills

Christopher Fonseca da Silva 27 February 2015 (has links)
Este trabalho apresenta um estudo sobre a influência do acréscimo de 4% de bentonita sódica, da anisotropia inerente, produzida pela compactação, e do estado de tensões no comportamento hidráulico de um solo areno-argiloso encontrado na região Costeira Sul do estado do Rio Grande do Sul. Neste estudo, busca-se não somente viabilizar o emprego do referido solo como barreira mineral em obras de proteção ambiental, mas também verificar seu desempenho, quando misturado ao aditivo, perante as condições de fluxo de água experimentalmente impostas, antes e depois da fase de consolidação, nas direções normal e paralela aos planos de orientação preferencial das partículas e poros a elas associados. Com o escopo de atingir tais objetivos, executaram-se dois métodos de compactação (ensaios Mini e Proctor Normal) para a moldagem de corpos de prova com planos de orientação preferencial das partículas ou de compactação normais (θ = 90º) e paralelos (θ = 0º) à vertical. As amostras de solo e mistura foram compactadas na energia Proctor Normal e submetidas aos ensaios triaxiais de condutividade hidráulica, em permeâmetro de parede flexível à carga constante, e de consolidação. A técnica permitiu determinar a condutividade hidráulica dos materiais para vazões desenvolvidas preferencialmente nas direções normal e paralela aos planos de compactação dos corpos de prova. Os resultados demonstram que o acréscimo de 4% de bentonita sódica provoca uma redução da condutividade hidráulica do solo, que supera o valor mínimo exigido de 10-9 m/s em ambas as direções de fluxo, habilitando o emprego deste material para a aplicação prevista. Além disso, verifica-se que a compactação confere um comportamento hidráulico anisotrópico ao solo, no entanto, quando misturado ao aditivo no teor indicado, seu comportamento se modifica, tornando-se mais isotrópico. Os resultados ainda revelam que o efeito da tensão de confinamento sobre a diminuição da condutividade hidráulica do solo e da mistura se mostra significativo para ambas as modalidades experimentais. / This work proposes to evaluate the influence of the inherent anisotropy, promoted by compaction, and the confining pressure on the hydraulic behavior of a clayey sand from the south coastal region of Rio Grande do Sul state (Brazil), in pure condition and mixed with 4% sodium bentonite content. This study aims to make possible the use of this soil as mineral barrier in environmental protection works, as well as evaluating the hydraulic behavior of both materials (soil and mixture), before and after the consolidation stage, when developed water flow conditions in the perpendicular and parallel directions in relation to the compaction planes of the compacted samples. In order to achieve these objectives, was performed a Standard Proctor Test and an alternative compaction test (Mini-test), intending to get specimens with compaction planes in the perpendicular (θ= 90º) and parallel (θ = 0º) directions in relation to the vertical. The soil and mixture samples were compacted at Normal Proctor energy and subjected to the triaxial consolidation and hydraulic conductivity tests. The technique allowed to evaluate the hydraulic conductivity of the specimens for flow perpendicular and parallel to the directions of the compaction planes. The results indicate that the increase of 4% sodium bentonite content reduces the hydraulic conductivity of the soil in both flow directions, making it suitable for employment as protection system in sanitary landfills or in other similar applications. Furthermore, it is observed that compaction provides anisotropic hydraulic behavior to the soil, however, when it is mixed with 4% sodium bentonite content, its behavior changes, becoming more isotropic. The results also reveal that the effect of the confining pressure on the decrease in hydraulic conductivity of the soil and mixture is significant in both adopted experimental conditions.
1022

Aspectos limnológicos e sanitários de uma lagoa costeira no litoral leste do Ceará - lagoa do Batoque / Limnological and sanitary aspects of a coastal lagoon in the eastern coast of Ceará – lagoa do Batoque

Eugênio Cunha Oliveira 08 May 2006 (has links)
As águas da lagoa do Batoque, uma lagoa costeira localizada no litoral leste do Estado do Ceará, foram caracterizadas por meio de coletas mensais realizadas em 4 pontos de amostragem, no período de maio a novembro de 2005 de maneira a obter dados do período seco (mai-jun) e chuvoso (ago-nov). Também foram realizadas duas coletas nictemerais (24h) em 1 ponto de amostragem nos meses de julho e dezembro de maneira a observar as variações diárias das variáveis limnológicas determinadas. Em cada coleta foram realizados perfis de temperatura, condutividade elétrica, turbidez, pH e oxigênio dissolvido e foi avaliada a transparência da água por meio do disco de Secchi. Ademais, foram coletadas amostras de subsuperfície e fundo para a investigação das variáveis: material em suspensão, cor, alcalinidade, compostos nitrogenados, fósforo solúvel reativo (PSR), fósforo total (PT), ferro total, ferro total dissolvido, clorofila a, densidade fitoplanctônica (organismos/mL) e coliformes (totais e termotolerantes). Os resultados demonstram que o sistema estudado apresentou variação sazonal relacionada aos dois períodos hidrológicos distintos. O período chuvoso se caracterizou por um período de precipitações mais intensas e menor insolação enquanto que o seco apresentou maior insolação e maiores velocidades dos ventos, trazendo conseqüências diretas sobre o nível d’água da lagoa estudada, a disponibilidade de nutrientes, o padrão de mistura do sistema, entre outros fatores. A grande variação encontrada no decorrer dos períodos nictemerais demonstrou a forte influência do fotoperíodo sobre a dinâmica do corpo d’água. Em relação à heterogeneidade espacial, foram verificados comportamentos diferenciados entre os diferentes pontos de superfície d’água livre. A coluna d’água não apresentou estratificação (térmica, química) significativa devido principalmente à baixa profundidade do sistema, à forte atuação dos ventos e à elevada transparência da coluna d’água. De acordo com o critério de classificação da OECD, a lagoa do Batoque pode ser considerada um ambiente mesotrófico. Os resultados obtidos sugerem que o sistema apresenta intenso processo de decomposição e regeneração de matéria orgânica, principalmente na região próxima ao sedimento, processo que atua como principal regulador da dinâmica de nutrientes no corpo d’água principalmente durante o período seco, já que durante o período chuvoso o sistema recebe cargas alóctones que dão condições à manutenção da produtividade do mesmo. A comunidade fitoplanctônica foi bastante influenciada pelas características físicas e morfométricas do sistema, como fortes ventos, alta insolação, baixa profundidade e alta transparência da coluna d’água, o que favoreceu o desenvolvimento de organismos fitobentônicos e organismos habituados a sistemas com boas condições de mistura. As baixas concentrações de nutrientes favoreceram o desenvolvimento de organismos de menor tamanho, que aparentemente têm maior facilidade de interação com a comunidade heterotrófica responsável pela ciclagem de nutrientes no sistema. A lagoa do Batoque, apesar de apresentar indícios de contaminação fecal, não está comprometida no que diz respeito à qualidade sanitária de suas águas de acordo com a legislação vigente (CONAMA 274/00 e 357/05). / The water quality of Batoque lagoon, a coastal lagoon located along the eastern shoreline of the state of Ceará, Brazil, was characterized by means of monthly samplings from May to November 2005 to obtain dry-season (May-Jun) and wet-season (Aug-Nov) data. Additionally, two nycthemeral (24hr.) samplings were performed in July and December to observe daily variation of the limnological variables investigated. Temperature, electrical conductivity, turbidity, pH, dissolved oxygen, and an assessment of water transparency (with Secchi disk) were measured in each water column sample. Moreover, subsurface and bottom samples were collected to determine the following variables: suspended material, color, alkalinity, nitrogen compounds ('NH IND.3,4'POT.+', 'NO IND.2'POT.-', 'NO IND.3'POT.-' and total nitrogen), soluble reactive phosphorus (SRP), total phosphorus (TP), total iron, total dissolved iron, chlorophyll a, phytoplankton density (org/mL), and coliforms (fecal and thermo tolerant). The results demonstrate that the system experiences seasonal variations related to the two distinct hydrological seasons. The wet season was characterized by intense rainfall and lower insolation. Whereas the dry season showed higher insolation and wind speeds directly influencing the water level of the lagoon as well as the availability of nutrients and the mixing pattern of the system, among other things. Furthermore, the high degree of variation observed during nycthemeral investigations demonstrated the strong influence of the photoperiod on the dynamics of this body of water. Variation in spatial heterogeneity among different sampling points was identified. The water column showed no significant stratification (thermal, chemical), due primarily to the low depth of the system, strong winds, and high water transparency. According to OECD classification criteria, Batoque lagoon can be considered a mesotrophic environment. The results obtained, suggest that the system is under an intense process of decomposition and regeneration of organic matter (primarily in the region nearest to the sediments). This process acts as the principal regulator of nutrient dynamics in the lagoon mainly during the dry season, since during the wet season the system receives allochthonous loads that contribute to maintaining the system’s productivity. The phytoplanktonic community was significantly influenced by the system’s physical and morphometrics features such as strong winds, high insolation, low depth, and high transparency of the water column which favor the development of phytobenthic organisms and those habituated to well-mixed environments. Additionally, the low nutrient concentrations favor the development of smaller organisms which apparently have greater ease of interaction with the heterotrophic community that is responsible for cycling nutrients in the system. Although Batoque lagoon presented indices of fecal contamination, it has not been shown to be compromised in relation to the sanitary quality of its waters according to current legislation (CONAMA 274/00 and 357/05).
1023

Caracterização de solo utilizado no sistema de barreira impermeabilizante de base de uma célula experimental de resíduos sólidos urbanos / Characterization of a soil used as sanitary landfill liner at an experimental cell of municipal solid waste

Leme, Mariane Alves de Godoy, 1988- 12 December 2013 (has links)
Orientador: Miriam Gonçalves Miguel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-24T02:43:30Z (GMT). No. of bitstreams: 1 Leme_MarianeAlvesdeGodoy_M.pdf: 3780913 bytes, checksum: 46059021b9d22c4aa2a0858bb94151e6 (MD5) Previous issue date: 2013 / Resumo: A geração dos resíduos sólidos urbanos (RSU) é uma ocorrência diária que deve ser gerenciada. Os aterros sanitários são os empreendimentos para disposição adequada desses resíduos. Dentre os constituintes estruturais dos aterros sanitários, há as barreiras impermeabilizantes de base, que podem ser de vários tipos, sendo as constituídas por solo argiloso compactado amplamente utilizadas. Este trabalho objetivou-se caracterizar o solo utilizado como camada mineral compactada no sistema de barreira impermeabilizante de base de uma célula experimental de RSU, no Aterro Delta A, em Campinas/SP. As amostras de solo foram coletadas em uma jazida localizada nas proximidades do aterro e caracterizadas por ensaios físicos, químicos, mineralógicos, geotécnicos e papel filtro para determinação das curvas de retenção do solo à água e ao lixiviado. Acompanhou-se a execução da camada mineral compactada em campo, obtendo-se grau de compactação de 100% e desvio de umidade de -3,8%. O solo apresentou resultados potenciais para ser utilizado como camada mineral compactada do sistema de barreira impermeabilizante de base de aterros sanitários, visto sua classificação pelo SUCS como CL, porcentagem de fração de finos maior que 30% e IP entre 10 e 30%, os quais atendem aos valores sugeridos pela literatura como requisitos a proporcionar valores de coeficientes de permeabilidade inferiores a 10-9 m/s, exigidos para solos utilizados com esta finalidade. Além da predominância à adsorção de cátions devido seu pH em estado natural encontrar-se acima do valor de Ponto de Carga Zero e sua fração sólida mineral apresentar argilominerais que oferecem propriedades coloidais como afinidade pelo lixiviado e elementos químicos nele dissolvidos. Da análise comparativa das curvas de retenção à água destilada e ao lixiviado, tem-se que o lixiviado provoca uma redução do valor da sucção para a umidade de campo, aumentando o coeficiente de permeabilidade da barreira impermeabilizante de base. Assim, a sucção osmótica foi um fator importante nas diferenças de comportamento dessas curvas / Abstract: The generation of municipal solid waste (MSW) is a daily occurrence that must be managed. Sanitary landfills are the enterprises for proper disposal of MSW. Among the structural constituents of sanitary landfill, are the liners, which can be made of different kinds, being the compacted clay liner widely used. This study aimed to characterize the soil used as mineral compacted layer at a liner of an experimental cell of MSW, located in Sanitary Landfill called Delta A, in Campinas city, São Paulo, Brazil. Soil samples were collected in a field reservoir located near the sanitary landfill, previously prepared and characterized by physic, chemical, mineralogical, geotechnical and filter paper tests, this latter test to determinate soil water (and leachate too) retention curves. The liner construction in field was followed, obtaining 100% of compaction degree of the soil and gravimetric moisture content of 3.8% below optimum. The soil presented potential to use as mineral compacted layer of sanitary landfill, since it was classified as CL by USCS, fine fraction percentage value greater than 30% and PI value between 10 and 30%, fitting with the values suggested by literature technical, as requirements to provide coefficient permeability values less than 10-9 m/s, which are required for soils used as sanitary landfill liners. Inn addition to the cations adsorption the soil presented predominance because of the natural pH value above the Load Point Zero value and the presence of clay minerals on solid fraction of the soil, showing colloidal properties that offer affinity for leachate and chemical elements dissolved in it. A comparative analysis of the retention curve to distilled water and leachate showed that leachate causes a reduction of the amount of suction at moisture field, increasing the permeability coefficient of the liner for leachate. Thus, the osmotic suction was one of the main factors responsible for the retention curves differences behavior / Mestrado / Saneamento e Ambiente / Mestra em Engenharia Civil
1024

Tratamento eletrolítico de lixiviado de aterro sanitário = Electrolytic treatment of landfill leachate / Electrolytic treatment of landfill leachate

Silveira, Jefferson Eduardo, 1986- 19 December 2012 (has links)
Orientador: Peterson Bueno de Moraes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-21T23:07:04Z (GMT). No. of bitstreams: 1 Silveira_JeffersonEduardo_M.pdf: 1833335 bytes, checksum: 71226fb620b38ed3dd8fd9ee6cfac08d (MD5) Previous issue date: 2012 / Resumo: A crescente degradação dos corpos d'água é assunto de constante interesse dos pesquisadores, da opinião pública e da mídia, devido à preocupação com a saúde pública, com os meios de produção e no legado às gerações futuras. Embora nos últimos anos as engenharias química, sanitária e ambiental tenham tido um significativo avanço nos métodos para tratamento de resíduos, alguns tipos de efluentes de composição complexa, como o lixiviado de aterro sanitário, não são adequadamente tratados pelos processos convencionais. Neste trabalho, propôs-se o uso da tecnologia eletroquímica, já utilizada na remedição de diversos tipos de resíduos e efluentes, para o desenvolvimento e aperfeiçoamento de um reator eletroquímico, em escala piloto, para tratamento do lixiviado do aterro sanitário do município de Limeira-SP. O lixiviado de aterro sanitário é um líquido escuro, com potencial patogênico, toxicológico e que pode conter compostos orgânicos como fenóis, pesticidas e íons metálicos. Foi utilizado um reator eletroquímico com eletrodos de titânio recobertos com 70%TiO2/30%RuO2 operando em batelada com recirculação, visando à redução da cor, carga orgânica e toxicidade. A partir dos resultados dos parâmetros físico-químico e biológicos, o sistema foi otimizado quanto à vazão, densidade de corrente, concentração de eletrólitos suporte e tempo de tratamento. Após 60 minutos de tratamento em densidade de corrente de 250 mA cm-2, concentração de eletrólito de 0,5 M de NaCl e vazão de 400 L h-1 foi possível remover 80% de DQO, 75% de N-NH3, 65% de COT e 90% de DBO. Levando-se em conta somente a remoção de amônia, a densidade de corrente mínima de 25 mA cm-2 já teve excelente desempenho após 30 minutos de tratamento. O sistema pode ser considerado economicamente viável para tratar este tipo de efluente em comparação aos tratamentos convencionais normalmente utilizados, com a vantagem de ser rápido, ocupar pouco espaço e não gerar lodo / Abstract: The increase in deterioration in the quality of water bodies is a subject of interest for researchers, public and media due to concern about public health. Although chemical engineering and environmental sciences have been experiencing lately significative advance in methods for wastewaters treatment, some types of effluents with complex composition such as landfill leachate are not adequately treated by conventional processes. In this work, we proposed the use of electrochemical technology, already used in the remediation of several types of waste and effluents, for development and improvement of an electrochemical pilot scale flow reactor for the treatment of raw landfill leachate from Limeira city, SP. The landfill leachate is a dark liquid with toxicological and pathogenic potential and may contain organic compounds such as phenols, pesticides and metallic ions. We used an electrochemical reactor with titanium oxide electrodes coated with 70% TiO2/30% RuO2 operating in batch recirculation mode, aiming to reduce color, organic load and toxicity. The electrochemical system was optimized from physicochemical and biological analyses considering the flow rate, current density, supporting electrolyte concentration and treatment time. Tests in 60 minutes at 250 mA cm-2, NaCl 0.5 M and flow rate of 400 L h-1 resulted on 80% COD, 75% NH3 - N, 65% TOC and 90% of BOD removal. Considering solely the removal of ammonia, 25 mA cm-2 was sufficed to reach a good performance in 30 minutes of treatment. The system showed be economically interesting for the treatment of this type of effluent when compared to conventional treatments normally used, because have the following advantages: higher degradation rates, small footprint, zero or low-generation of sludge / Mestrado / Tecnologia e Inovação / Mestre em Tecnologia
1025

Reforma del sector salud en el Perú: Derecho, gobernanza, cobertura universal y respuesta contra riesgos sanitarios

Velásquez, Aníbal, Suarez, Dalia, Nepo-Linares, Edgardo 09 1900 (has links)
In 2013, Peru initiated a reform process under the premise of recognizing the nature of health as a right that must be protected by the state. This reform aimed to improve health conditions through the elimination or reduction of restrictions preventing the full exercise of this right, and the consequent approach aimed to protect both individual and public health and rights within a framework characterized by strengthened stewardship and governance, which would allow system conduction and effective responses to risks and emergencies. The reform led to an increase in population health insurance coverage from 64% to 73%, with universalization occurring through the SIS affiliation of every newborn with no other protection mechanism. Health financing increased by 75% from 2011, and the SIS budget tripled from 570 to 1,700 million soles. From 2012 to May 2016, 168 health facilities have become operational, 51 establishments are nearing completion, and 265 new projects are currently under technical file and work continuity with an implemented investment of more than 7 billion soles. Additionally, this reform led to the approval of the Ministry of Health intervention for health emergencies and strengthened the health authority of the ministry to implement responses in case of risks or service discontinuity resulting from a lack of regional or local government compliance with public health functions. / In 2013, Peru initiated a reform process under the premise of recognizing the nature of health as a right that must be protected by the state. This reform aimed to improve health conditions through the elimination or reduction of restrictions preventing the full exercise of this right, and the consequent approach aimed to protect both individual and public health and rights within a framework characterized by strengthened stewardship and governance, which would allow system conduction and effective responses to risks and emergencies. The reform led to an increase in population health insurance coverage from 64% to 73%, with universalization occurring through the SIS affiliation of every newborn with no other protection mechanism. Health financing increased by 75% from 2011, and the SIS budget tripled from 570 to 1,700 million soles. From 2012 to May 2016, 168 health facilities have become operational, 51 establishments are nearing completion, and 265 new projects are currently under technical file and work continuity with an implemented investment of more than 7 billion soles. Additionally, this reform led to the approval of the Ministry of Health intervention for health emergencies and strengthened the health authority of the ministry to implement responses in case of risks or service discontinuity resulting from a lack of regional or local government compliance with public health functions.
1026

Analyse et représentation des épisodes de caniculaires en zones urbaines denses : de la durée à la conception d'un indice de dangerosité / Analysis and representation of the episodes of heat waves on the scale of districts

Pinson, Laura 24 November 2016 (has links)
Le GIEC (groupe d’expert Intergouvernemental sur l’Evolution du Climat) dans leur 4 ème rapport souligne que les villes européennes seront impactées par des épisodes caniculaires plus fréquents et plus intenses dû aux modifications climatiques ayant lieu au cours du XXI ème siècle. La ville, espace climatique particulier, sensiblement plus chaud que son espace environnant amplifie le phénomène de l’îlot de chaleur urbain (ICU). Pour la ville de Paris, les îlots de chaleur urbains peuvent dépasser de 8 à 10°C les températures relevées quelques kilomètres plus loin. Cet effet est d’autant plus néfaste lors de période caniculaire comme a connu la France en 2003, 2006, 2010 ou bien même en 2015. La connaissance sur le phénomène de la canicule nécessite de mettre en relation des données autant spatiales que temporelles afin de définir des zones à risques .Pour pouvoir simuler une canicule, le modèle SURFEX-TEB, conçu par Météo-France, CNRS, a été choisi. Il permet d’estimer la température en ville à partir de conditions climatiques des plus hautes atmosphères. Ces prévisions sont importantes notamment en période de canicule où les écarts de température entre la ville et sa banlieue peuvent dépasser 8C°. Le risque caniculaire, induit par les ICU, est complexe à appréhender et à représenter.Pour caractériser, appréhender et représenter la canicule, avec l’aide du modèle SURFEX-TEB, nous avons effectué une assimilation avec des mesures réalisées pendant la canicule de 2015 sur Paris. Cette assimilation met en évidence par exemple les phénomènes d’accumulation et l’impact des configurations des appartements sur les températures intérieures et extérieures. Nos différentes configurations ont permis de confirmer l’importance de considérer les températures intérieures lors de périodes caniculaires.Ce travail de recherche propose donc un éclairage spécifique et technique de la représentation des canicules. Son objectif est une meilleure représentation des canicules et l’estimation de leur dangerosité en fonction de la durée du phénomène, de son intensité et des caractéristiques urbaines et humaines. Des cartes décrivant la canicule et sa dangerosité sont mises en valeur grâce à l’élaboration d’un site web grand public.Les résultats de cette recherche soulèvent une interrogation sur les seuils de canicule. Ils soulignent l’importance d’introduire un seuil de canicule intérieur et démontrent le rôle de la configuration urbaine et en particulier des types d’habitation pour mieux prendre en compte la dangerosité des canicules et espérer mieux atténuer leurs effets / The IPCC (Intergovernmental Panel on Climate Change) in its 4th report underlines that the European cities will be impacted by more frequent and more intense scorching episodes due to the climatic modifications taking place during the XXIth century. Peculiar climatic areas, significantly hotter than their surroundings, cities amplify the phenomenon of the urban heat island (UHI). In the example of Paris, the urban islands of heat can exceed by 8°C to 10°C the temperatures measured a few kilometers away. This effect is all the more fatal as heat wave periods become more and more regular (2003, 2006, 2010, 2015). The knowledge on the heat wave phenomenon requires to put in relation spatial and temporal data so as to define high-risk areas.To be able to simulate a heat wave, the SURFEX-TEB model, designed by Météo-France, and CNRS, was chosen. It allows to estimate the temperature in town from weather conditions of the highest atmospheres. These forecasts are particularly important in heat wave periods where temperature differences between cities and suburban areas can exceed 8°C. The heat wave risk, resulting from the UHI, is complex to both understand and represent.To characterize, understand and represent the heat wave by the means of the SURFEX-TEB model, we made a data fusion with measures realized during the 2015 heat wave in Paris. This assimilation highlights, for instance, the accumulation phenomena and the impact of the apartments configuration on the inside and outside temperatures. Our various configurations allowed to confirm the importance of taking into account the internal temperatures during heat waves periods.This research thus proposes a specific and technical perspective of the heat waves representation. Its objectives are a better representation of heat waves and a sharper estimation of their dangerousness according to the phenomenon duration, its intensity and the urban and human features. Maps describing the heat wave and its dangerousness are highlighted thanks to the elaboration of a public Web site.The results of this research rise an interrogation on the thresholds of heat wave. They underline the importance to introduce an internal threshold of heat wave and demonstrate the role of the urban configuration, particularly the types of house. This should contribute to better take into account the dangerousness of heat waves and to improve the mitigation of their effects
1027

Non-invasive velocity and volume fraction profile measurement in multiphase flows

Al-Hinai, Sulaiyam January 2010 (has links)
Multiphase flow is the simultaneous flow of two or more phases, in direct contact, and is important in the oil industry, e.g. in production wells, in sub-sea pipelines and during the drilling of wells. The behaviour of the flow will depend on the properties of the constituent phases, the flow velocities and volume fractions of the phases and the geometry of the system. In solids-in-liquid flows, measurement of the local solids volume fraction distribution and the local axial solids velocity distribution in the flow cross section is important for many reasons including health and safety and economic reasons, particularly in oil well drilling operations. However upward inclined solidsliquid flows which are frequently encountered during oil well drilling operations are not well understood. Inclined solids-liquid flows result in non- uniform profiles of the solids volume fraction and axial solids velocity in the flow cross- section. In order to measure the solids volumetric flow rate in these situations it is necessary to measure the distributions of the local solids volume fraction and the local axial solids velocity and then to integrate the product of these local properties in the flow cross section. This thesis describes the development of a non-intrusive Impedance Cross-Correlation (ICC) device to measure the local solids volume fraction distribution and the local solids axial solids velocity distribution in upward inclined solids-water flows in which these distributions are highly non-uniform. The ICC device comprises a non-conductive pipe section of 80mm internal diameter fitted with two arrays of electrodes, denoted „array A‟ and „array B‟, separated by an axial distance of 50mm. At each array, eight electrodes are equispaced over the internal circumference of the pipe. A control system consisting of a microcontroller and analogue switches is used such that, for arrays A and B, any of the eight electrodes can be configured as an "excitation electrode" (V+), a "virtual earth measurement electrode" (Ve) or an "earth electrode" (E) thus enabling the local mixture conductance in different regions of the flow cross-section to be measured and thereby allowing the local solids volume fraction in each region to be deduced. The conductance signals from arrays A and B are also cross-correlated to yield the local solids axial velocity in the regions of flow under interrogation. A number of experiments were carried out in solids-in-water flows in a flow loop with an 80 mm inner diameter, 1.68m long Perspex test section which was inclined at three different inclination angle to the vertical ( o 0 , o 15 and o 30 ). The obtained results show good quantitative agreement with previous work carried out using intrusive local probes. Integration of the flow profiles in the cross section also yielded excellent quantitative agreement with reference measurements of the mean solids volume fraction, the mean solids velocity and the solids volumetric flow rate. Furthermore, this study also showed good qualitative agreement with high speed film of the flow. It is believed that the method of velocity and volume fraction profile measurement described in this thesis is much simpler to implement, more accurate and less expensive than the currently very popular technique of dual-plane Electrical Resistance Tomography (ERT). Finally, the thesis describes a mathematical model for predicting the axial velocity distribution of inclined solids-water flows using the solids volume fraction profiles measured by the ICC device. Good agreement was obtained between the predicted velocity profiles and the velocity profiles measured using the ICC device.
1028

A Generalised Two Layer Model For Transient Flow To A Pumped Well

Badarinath, A 01 1900 (has links) (PDF)
No description available.
1029

Modeling Of Contaminant Transport Through Soils And Landfill Liners

Bharat, Tadikonda Venkata 10 1900 (has links)
Accurate modeling of contaminant transport and sorption processes in the soil and landfill liners is a prerequisite for realistic model simulations of contaminant fate and transport in the environment. These studies are also important for the remediation of soil and groundwater contamination. Modeling of contaminant transport through soils and landfill liners consists of either solving the direct/forward problem or the inverse problem. In this thesis, an automated time-stepping implicit procedure is developed from the convergence and error studies of explicit and implicit finite-difference solutions for the advection-dispersion transport of contaminants through soil with different sorption mechanisms. This study is further extended for transient through-diffusion (TTD) transport of contaminant in landfills by considering linear sorption mechanism. To validate the numerical solution and also to study the behavior of finite-difference numerical solutions for TTD transport problem, closed-form analytical solution is derived. Further, a new interface condition is proposed based on the finite-volume procedure for stratified soil or landfill liner system. Solvers are developed for the parameter estimation of inverse problem by integrating the developed procedures for the above forward problem with different optimization procedures. Solvers based on Simulated Annealing (SA) and Genetic Algorithm (GA) are developed for TTD transport in the landfill liners and verified with the existing methods of parameter estimation. Novel swarm intelligence based solver is developed for the first time for parameter estimation in contaminant transport inverse problem to overcome some of the limitations of the classical optimization methods and evolutionary methods such as GA. Additionally, the proposed swarm intelligence based algorithms and a new variant is applied to solve ill-posed problem of contaminant source characterization. The presented work in this dissertation can be unswervingly applied for modeling the contaminant transport in laboratory through-diffusion tests and contaminant transport through landfill liners where the transport is usually considered to be one-dimensional and also diffusion-dominated. Similarly, the advection-dispersion transport through laboratory soil columns can also be modeled with the developed, fast, automated, implicit numerical procedure with very good accuracy. The present study can be applied further for contaminant transport through stratified soil/liner system using fast converging numerical algorithms. Finally, the problems of design parameter estimation and source characterization can be handled accurately by the use of developed automated nature-inspired solvers.
1030

Možnosti vstupu zahraničních firem na čínský realitní trh a návazné sektory / Entry Options of Foreign Companies into the Chinese Real Estate Market and Related Sectors

Švecová, Ivana January 2013 (has links)
This thesis deals with the entry options of European SME companies into the Chinese sanitary market. The paper identifies four main objectives, which are: 1. Introduce the entry options of foreign companies into the Chinese market. 2. Summarize the development of China's real estate market. 3. Compare selected foreign companies in the Chinese sanitary ware market. 4. Evaluate whether the entry of a European SME into the Chinese sanitary market would be a strategically correct step. The thesis is divided into three chapters. These chapters are divided into two sections. The first chapter is the theoretical foundation of the thesis. It introduces motives and entry options of companies into foreign markets in terms of theory, and motives and general options of entering the Chinese market. The second chapter deals with the Chinese real estate market and related sectors. The related sectors are specified on furniture and sanitary market. The third chapter introduces foreign manufactures of sanitary ware on the Chinese market -- American company Kohler, Spanish company Roca and Czech company Ravak. The second part of the third chapter evaluates the felicitous target group, geographic location, marketing and sales options of the foreign companies in the Chinese market. At the end of this chapter a potential entry of European SME into the Chinese sanitary market is evaluated.

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