Thesis (M.Eng.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 130-137.

Understanding the physics of multiphase plumes and their simulation through numerical modeling has been an important area of research in recent times in the area of environmental fluid mechanics. The two renowned numerical modeling types that are commonly used by researchers today to simulate multiphase plumes in nature are the mixed-fluid and the two-fluid integral models. In the present study, a detailed review was performed to study and analyze the two modeling approaches for the case of a double plume (upward moving inner plume with downward moving annular outer plume) with the objective of ascertaining which of these models represent the prototype physics in the integral plume model equations with a higher degree of completeness and accuracy. A graphical user interface was designed to facilitate running the models. By comparison to laboratory scale experimental data and through sensitivity analyses, a rigorous effort was made to determine the most appropriate choice of initial conditions needed at the start of the model computation and at the peeling locations and to obtain the most consistent values of the different model parameters that are necessary for calibration of the two models. Consequently, with these selected sets of initial conditions and model parameters, the models were run and their outputs compared against each other for three different case studies with ambient conditions typical of real environmental data. The dispersed phases considered were air bubbles in two cases and liquid CO2 droplets for the third case, with water as the continuous phase in all cases. The entrainment coefficient was found to be the most important parameter that affected the model results. In all the three case studies conducted, the mixed-fluid model was found to predict about 30% higher values for the peel heights and the DMPR (Depth of Maximum Plume Rise) than the two-fluid model.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: CFD; computational fluid dynamics; plume; nozzle; DSMC; numerical modelling. Includes bibliographical references (p. 83-86).

Building environmental conditions such as ventilation and contaminant concentrations are important factors that influence occupant health and comfort. The objective of the present work is to investigate how personal exposure to gaseous and particulate pollutants depends on indoor airflow, source characteristics, and occupant activity in commercial and residential environments. The study examines airflow and pollutant transport using experimental measurements in conjunction with computational fluid dynamics (CFD). The results demonstrate that breathing has a measurable influence on the airflow in an occupant breathing zone, but it has very small impacts on the occupant thermal plume. The results also show that breathing can significantly affect inhaled particle concentrations, even though the influence varies with source position and particle size. Also, localized hand motions of a sitting manikin do not significantly disrupt the upward thermal plume. In typical US residences, forced convection driven mixing airflow or buoyancy driven stratified airflow occurs depending on the HVAC fan operation (fan on or fan off, respectively). The measured transition period between mixing flow (fan on) and stratified flow (fan off) is approximately one minute, implying that most airflow in the residence is either dominated by mixing or stratification. A high level of exposure to short-term pollutant sources, such as resuspension of particles from floor surfaces due to human activity, more likely occurs with stratified flow than with highly mixed airflow. This is due to the strong influence of the occupant thermal plume that transports the pollutants into the breathing zone. Furthermore, by transporting air containing ozone across the reactive occupant surface, the occupant thermal plume has a large effect on exposure to ozone reaction products. Due to the reaction of ozone with the skin oils and clothing surfaces, the occupant surface boundary layer becomes depleted of ozone and conversely enriched with ozone reaction products. The parameter ventilation effectiveness quantifies the effectiveness of airflow distribution and can be used for assessment of exposure to gaseous pollutants. Based on the study results, the usefulness of ventilation effectiveness as an indicator of exposure to particulate pollutants depends on the particle size. For small particles (~1 [mu]m), an increase of ventilation effectives caused a decrease in occupant exposure, while for large particles (~7 [mu]m), source location and airflow around the pollutant source are significant factors for the exposure, and the ventilation effectiveness has very little to no effect. / text

Eulerian chemical transport models are extensively used to steer environmental policy, forecast air quality and study atmospheric processes. However, the ability of these models to simulate concentrated atmospheric plumes, including fire-related smoke, may be limited. Wildland fires are important sources of air pollutants and can significantly affect air quality. Emissions released in wildfires and prescribed burns have been known to substantially increase the air pollution burden at urban locations across large regions. Air quality forecasts generated with numerical models can provide valuable information to environmental regulators and land managers about the potential impacts of fires. Eulerian models present an attractive framework to simulate the transport and transformation of fire emissions. Still, the limitations inherent to chemical transport models when applied to replicate smoke plumes must be identified and well understood to adequately interpret results and further improve the models' predictive skills. Here, a modeling framework centered on the Community Multiscale Air Quality modeling system (CMAQ) is used to simulate several fire episodes that occurred in the Southeastern U.S. and investigate the sensitivity of fine particulate matter concentration predictions to various model inputs and parameters. Significant sources of uncertainty in the model are identified and discussed, including the spatiotemporal allocation of fire emissions and meteorological drivers. In addition, special attention is given to model grid resolution. Adaptive grid modeling is explored as a strategy to simulate fire-related plumes. An adaptive version of CMAQ, capable of dynamically restructuring the grid on which solution fields are estimated and providing refinement at the regions where accuracy is most dependent on resolution, is presented. The fully adaptive three-dimensional modeling technique can be applied to reach unprecedented levels of grid resolution and provide insight into plume dynamics unattainable with static grid models. Through this work the capability of current chemical transport models to replicate fire-related air quality impacts is evaluated, key research needs to achieve effective simulations are identified, and numerical tools designed to improve model performance are developed.

An electrochemical sensor array can provide information about the spatial and temporal distribution of chemicals in liquid turbulent plumes. Planar laser induced fluorescence (PLIF) and amperometric sensor arrays were used to record signals from modulated chemical plumes released into a recirculating aquatic flume. Coherence analysis was applied to extract the frequency components contained in the sensor response. Effects due to release distance, modulation frequency, and array orientation were investigated. This study has demonstrated that frequency encoded information can be extracted from a turbulent chemical plume using an array of amperometric sensors with optimized three-dimensional geometry and tuning.

Thesis (Ph.D.) - University of Glasgow, 2007. / Ph.D. thesis submitted to the Department of Geographical and Earth Sciences, Physical Sciences Faculty, University of Glasgow, 2007. Includes bibliographical references. Print version also available.

Thesis (Ph. D.)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Sept. 9, 2009). Vita. Includes bibliographical references.

A plataforma continental da área de Cabo Frio, localizada no extremo SW da Bacia de Campos e extremo NW da Bacia de Santos, possui distintas feições em sua evolução tectono -sedimentar quando comparada com outras áreas das referidas bacias. Entre essas feições, destaca-se a presença de falhas antitéticas no embasamento e nas seções sedimentares sin-rifte e pós-rifte, além de eventos magmáticos marcantes no Neocretácio e Eoterciário, com clímax no Eoceno Médio. O presente trabalho mostra uma perspectiva histórica da percepção humana dos fenômenos magmáticos, desde as primeiras teorias míticas e teológicas da antiguidade, até o atual debate entre os que adotam ou não o modelo de plumas mantélicas. Tais informações são necessárias para um melhor entendimento das conclusões aqui apresentadas. A base de dados do presente estudo consiste de análises detalhadas de dados de sísmica, de satélite, de métodos potenciais (magnéticos e gravimétricos) e de poços. Amostras de diques básicos na península de Arraial do Cabo, situada na porção continental mais próxima do limite entre as Bacias de Santos e de Campos, foram coletadas para estudos geocronológicos. O estudo integrado de todos esses dados confirmou o resultado de pesquisas anteriores, as quais identificaram dois eventos magmáticos principais, um no Santoniano/Campaniano (~ 83 Ma) e outro no Eoceno Médio (~ 50 Ma). Há também evidências, em seções sísmicas, de edifícios vulcânicos formados durante o Albiano, o Maastrichtiano e o Paleoceno. As análises de dados de sísmica de relexão e de perfis de poços, na área de estudo, revelaram uma série de feições diagnósticas para eventos magmáticos, incluindo a distinção entre eventos intrusivos dos extrusivos, bem como de intercalações entre os mesmos e seqüências sedimentares epiclásticas. Eventos magmáticos extrusivos podem ser identificados, nas seções sísmicas, como sismofácies caóticas com topos bem definidos e bases mal definidas. Tais sismofácies são interpretadas como o resultado da intercalação de derrames submarinos de lavas com sedimentos epiclásticos e vulcanoclásticos, juntamente com feições de escorregamentos e soleiras rasas. A presença de cones bem delimitados também constitui evidência de magmatismo extrusivo. Diques e derrames de lava são reconhecidos por fortes reflexões positivas com terminações laterais abruptas. Diques mais espessos de diabásio originam zonas com fracas reflexões, delimitadas acima e abaixo por fortes reflexões. Os critérios apresentados nessa tese podem ser aplicados a quaisquer contextos em que haja eventos magmáticos intercalados com seqüências sedimentares. A assinatura sísmica de eventos não- magmáticos é também mostrada; tais eventos correspondem a diferentes feições geológicas que podem ser interpretados por geofísicos e geólogos como sendo de origem magmática. Entre tais eventos, os mais importantes são os evaporitos, os mounds turbidíticos, os vulcões de lama originados por escape de gás e depósitos carbonáticos. Serão apresentadas algumas interpretações para a gênese do magmatismo pós-Aptiano na área em epígrafe, interpretações essas que não levam em conta o modelo clássico de plumas mantélicas. O mapeamento dos principais diques alimentadores, em seções sísmicas 2D e 3D, revelou que tais diques têm uma orientação preferencial SE-NW, coincidente com o alinhamento da Zona de deformações Cruzeiro do Sul, a qual inclui os Montes Submarinos Jean Charcot e as construções vulcânicas no Alto de Cabo Frio e suas cercanias. Tal observação é coerente com as características das falhas de rejeito direcional, preexistentes e reativadas nas áreas continentais próximas, e com a orientação do componente transtensional das mesmas. Além disso, comprova-se que os maiores volumes de rochas magmáticas, intercaladas na seção sedimentar, estão localizados nas áreas de interseção entre duas zonas de falhas com direção SE- NW (falhas de rejeito direcional) e SW-NE (falhas normais). O mesmo acontece com os corpos alcalinos do alinhamento Poços de Caldas-Cabo Frio. / The continental shelf of the Cabo Frio Area, at the southern part of the Campos Basin, shows unique features in its tectono-sedimentary evolution when compared to other areas of the Campos and Santos basins. The presence of a regular pattern of antithetic faults in the basement and in the syn-rift and the post-rift sedimentary sections, along with important magmatic events in the Late Cretaceous and Early Tertiary sequences (whose climax took place in the earli er portion of the Middle Eocene) are some of these features. This work presents a historical perspective of the human perception of the magmatic events, from the ancient mythic and theologic theories to the current debate between plumers and non-plumers. These informations are needed to allow a better understanding of the conclusions of the present thesis. The present study was based on the analyses of seismic, satellite, magnetic, gravimetric and well data, as well as rock samples collected in dikes cropping out at the Arraial do Cabo Peninsula, the nearest onshore position at the boundary between the offshore Santos and Campos Basins. This thesis has confirmed the results of previous research that had identified two major magmatic pulses, one in the late Cretaceous and the other in the Early Tertiary (~83 and 50 My, respectively). There is also seismic evidence for volcanic edifices formed during the Albian, Maastrichtian and Paleocene times. The analyses of seismic reflection and well log data, in the working area, points to a set of diagnostic features that can lead to the identification of magmatic events and the distinction of intrusive from extrusive rocks, as well as their intercalations with epiclastic sedimentary sequences. Extrusive magmatic events can be recognized in seismic reflection data as chaotic seismofacies with well defined tops and poorly defined bases; these seismofacies are interpreted as a result of interbedding submarine lava flows and epiclastic and volcaniclastic sediments, along with slumps and shallow intrusions (sills). The presence of well shaped conic edifices also points to extrusive magmatism. Dikes and lava flows are recognized by strong positive reflections with abrupt lateral ends. Thicker dolerite sills may be recognized by re flection free zones with strong reflections in their tops and bases. The criteria proposed by this thesis may be used to identify and classify magmatic events in any context where they are associated with sedimentary sequences. The thesis also shows the seismic signatures of nonmagmatic events, which comprise a different range of geologic features that may induce the geophysicists and geologists to interpret them as magmatic events. Among these features, evaporites, turbiditic mounds, mud volcanoes originated by gas escape, slump seismofacies and carbonate deposits are the most important ones. Some alternative interpretations to explain the genesis of this magmatism are presented, which do not take into account the classic model of mantle plumes. The mapping of the main feeder dikes, in 2D and 3D reflection seismic sections, has revealed that they have a predominant SE-NW direction, coincident with the alignment of the Cruzeiro do Sul Deformation Zone, which includes the Jean Charcot submarine mounds and the volcanic mounds on and around the Cabo Frio High. This observation is coherent with the characteristics of the preexisting and reactivated strike-slip faults on land and the orientation of their transtensional component. Moreover, it is shown that the largest volumes of magmatic rocks, intercalated in the sedimentary section, are located at areas of intersections between fault zones trending SE-NW (strike -slip faults) and SW-NE (normal faults), as are the onshore alkaline bodies of the Poços de Caldas Cabo Frio alignment.

O principal objetivo deste estudo é estimar o alcance dos poluentes emitidos pelo Aterro Controlado do Morro do Céu (ACMC), localizado em Niterói e as possíveis áreas afetadas. Utilizou-se um modelo matemático para o estudo do transporte e difusão dos poluentes que fornece a concentração nas vizinhanças, a partir dos dados de emissões, meteorológicos e topográficos. Foram analisados e tratados os dados meteorológicos e a topografia da região de alcance da pluma. As amostras foram coletadas por uma bomba de ar a uma vazão de 500 mL min-1 por um período de 10 min, em dois dias e horários diferentes. A câmara de fluxo empregada foi de 30 L e de PVC, no formato cilíndrico, cuja boca foi emborcada no solo por 5 cm e a amostragem realizada por uma válvula posicionada no fundo. Foram empregados como meios de amostragem cartuchos de carvão ativo de leito duplo e as análises químicas foram realizadas por cromatografia de fase gasosa com detecção por ionização na chama. Os resultados encontrados indicam que o ACMC pode conter quantidade significativa de vários compostos químicos, principalmente compostos orgânicos voláteis, impactando a vegetação, prejudicando a saúde e a qualidade de vida da população do seu entorno. Foram obtidos valores de compostos orgânicos voláteis acima de 400 g m-3 a menos que 500 m do ACMC. Considerando que o ACMC não será desativado em um tempo próximo, creches, escolas e postos de saúde devem ser deslocados para uma área onde o impacto dos poluentes atmosféricos seja menor, contribuindo para a melhoria da qualidade de vida da população / The main purpose of this work is to evaluate the impacted areas of the pollutants emitted by Aterro Controlado do Morro do Céu (ACMC), located at Niterói. It was used the ISCSC3 mathematical model to calculate the diffusion and the transport of the pollutants, in order to estimate the concentrations at the neighborhood, using the emissions, meteorological, and topographical data. The samples were collected at 500 mL min-1 using a battery-operated air pump during 10 minutes, at two days at different hours. It was used a cylindrical PVC flux chamber of 30 liters, whose open top side was inserted inside soil by 5 cm, and the samples were collected using a valve at the opposite closed side. It were used double bed activated charcoal cartridges and the chemical analyses were done by gas chromatography with flame ionization detector. The results indicated that ACMC may contain several chemical compounds, mainly volatile organic compounds, causing injures to vegetation and human health at the vicinities. Values above 400 g m-3 for VOCs were found near 500 m from the landfill. As ACMC will be used for a long time it is necessary to evaluate the possibility to change the location of several schools, crèches, and hospitals to avoid the impacts of a contaminated plume arise from ACMC