The pollution generated by accidental marine oil spills can cause persistent ecological disasters and lead to serious social and economical damages. Numerical simulations are a valuable tool to make proper decisions in emergency situation or to plan response actions beforehand. The main objective of this work was to improve SIMOIL, a computational model developed earlier at URV and capable of predicting the evaporation and spreading of massive oil spills in coastal areas. Specifically, a new coastal current model, based on the resolution of the shallow water equations in generalised coordinates, has been developed and validated and then coupled to SIMOIL. The model was specially designed to describe coastal oceanic flows over topography accounting for Coriolis force, eddy viscosity, seabed friction and to couple with SIMOIL in domain with complex boundaries. The equations have been discretized over generalised domains by means of finite differences of second order accuracy. The code was then implemented in FORTRAN. The code has been validated extensively against numerical and experimental flow studies of the bibliography. Finally, the new complete version of SIMOIL, coupling the shallow water model and the oil slick model, has been applied to the study of two accidental oil spills: • A massive leakage from the Repsol's floating dock in the port of Tarragona • The biggest oil spill ever occurred in the Eastern Mediterranean Sea: the 2006 Lebanon oil spill. In both cases, the new version of SIMOIL, demonstrate more accurate predictions of the behaviour of the oil spill, specially for moderate winds with complex topography. / La contaminación generada por los vertidos accidentales de petróleo puede ser reducida si se actúa y si se toman las decisiones adecuadas a tiempo. Las simulaciones numéricas de vertidos de petróleo permiten predecir la evolución de las manchas de crudo. En este trabajo, el objetivo principal era de mejorar la precisión y el rango de aplicación del código SIMOIL desarrollando e integrando al código un modelo de predicción de corrientes marinas en aguas costeras. Se han derivado las ecuaciones de aguas poco profundas en coordenadas generalizadas. Se han discretizado las ecuaciones y el código se implementó en FORTRAN 90. El modelo así como los métodos numéricos han sido validados con el estudio de flujos experimentales y numéricos de la bibliografía. Finalmente, la nueva versión de SIMOIL se aplicó con éxito a dos casos físicos de vertidos de crudo: • un vertido ficticio desde la monoboya de descarga de Repsol en el puerto de Tarragona • un vertido real, el mas grande ocurrido en el Este del mar Mediterráneo, consecuencia de la guerra en Líbano en julio de 2006. En ambos casos la nueva versión de SIMOIL proporcionó predicciones más precisas, especialmente para vientos moderados y topografías complejas.

This thesis concerns the occurrence of the large-scale bed and plan forms known as alternate bars and meandering, and the internal structures of the flow associated with their formation. The work is to be viewed as an extension of previous work by da Silva (1991), Yalin (1992), and Yalin and da Silva (2001). As a first step in this work, the criteria for occurrence of alternate bars and meandering of Yalin and da Silva (2001) is re-considered in view of additional field and laboratory data from the recent literature and data resulting from two series of experimental runs carried out in two sediment transport flumes. This leads to a number of modifications of the boundary-lines in the related existence-region diagram of Yalin and da Silva. The size of the largest horizontal coherent structures (HCS’s) of an alternate bar inducing flow was then investigated experimentally on the basis of three series of flow velocity measurements. These were carried out in a 21m-long, 1m-wide straight channel, conveying a 4cm-deep flow. The bed consisted of a silica sand having a grain size of 2mm; its surface was flat. The measurements were carried out using a Sontek 2D Micro ADV. The horizontal burst length was found to be between five and seven times the flow width. The effect of the HCS’s on the mean flow was also investigated. A slight internal meandering of the flow caused by the superimposition of burst-sequences on the mean flow was clearly detectable. Finally, with the aid of three new series of measurements in the same channel, an attempt was made to penetrate the dynamics and life-cycle of the HCS’s. For this purpose, quadrant analysis was used; the cross-sectional distribution of relevant statistical turbulence-related parameters was investigated; and cross-correlations of flow velocity along the flow depth and across the channel were performed. The analysis indicates that the HCS’s originate near the channel banks, with the location of ejections and sweeps being anti-symmetrically arranged with regard to the channel centreline, and then evolve so as to occupy the entire depth of the water and the entire width of the channel. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2010-03-09 10:20:53.596

The overall objectives of this thesis are to determine if Indirect and Direct Design methods currently used for reinforced concrete pipe are able to accurately predict the capacity of the pipe, to identify discrepancies between the two methods, and to provide potential modifications to the methods to reduce inconsistencies. As part of this investigation, two 0.6 m pipes (nominal strength classes 100-D and a 140-D) and two 1.2 m pipes (a 65-D with Wall B and a 65-D with Wall C) were tested under single wheel pair loading at burial depths of 1.2, 0.6 and 0.3 m. The test pipes did not crack at the applied service load of 110 kN and did not pass the crack width limit until between 2.5 and 4 times the service load. A 0.6 m 100-D pipe was also tested under simulated deep burial and it was found that the calculated test D-Load is 1.9 times greater than the designated D-Load of the test pipe. It was found that both methods were conservative and that the Direct Design method should be modified to more closely align with the Indirect Design. An investigation of the Direct Design parameters found that by considering thick ring theory and the Modified Compression Field Theory with two layers of reinforcement, the required amount of steel from Direct Design could be made to align very closely with the Indirect Design. An additional test was completed to further assess the Direct Design method on a 0.6 m 140-D pipe to measure the pressure around the circumference of the pipe and compare this measured pressure to the commonly used pressure distribution for Direct Design. The results show that at the minimum cover (0.3 m) the test pressure is higher than predicted at the crown, lower than predicted at the invert, and nearly zero at the shoulder, springline, and haunch, which is inconsistent with most of the predicted results at these locations. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-06-20 16:29:39.037

The occurrence of As in groundwater in Argentina was known since 1917; however, the occurrence, distribution and mobilization of As and other trace elements (TEs) in groundwater in the Bolivian Altiplano are still quite unknown. An investigation applying a geochemical approach was conducted in the Poopó Basin and Lake Titicaca to understand processes of TEs in different systems such as water, soils, crops and sediments in mining areas. In Poopó Basin,As, Cd and Mn concentrations exceed World Health Organization (WHO) guidelines and Bolivian regulations for drinking water in different places around the basin, but Cu, Ni, Pb and Zn do not. In soils, the sequential extraction methods extracted up to 12% (fractions 1 and 2), which represent &lt; 3.1 mg/kg of the total As content, as potentially mobilized fractions, that could be transferred to crops and/or dissolved in hydrologic system. The large pool of As can be attached due to amorphous and crystalline Fe oxide surfaces (fractions 3, 4, and 5) present in the soils. Furthermore, the concentrations of As, Cd and Pb in the edible part of the crops revealed that the concentrations of As and Cd do not exceed the international regulation (FAO, WHO, EC, Chilean) (0.50 mg/kgfw for As and 0.10 mg/kgfw for Cd), while Pb exceeds the international regulations for beans and potatoes (for beans 0.20 mg/kgfw and for potato 0.10 mg/kgfw). In the Lake Titicaca, principal component analysis (PCA) of TEs in sediments suggests that the Co-Ni-Cd association can be attributed to natural sources such as rock mineralization, while Cu-Fe-Mn come from effluents and mining activities, whereas Pb-Zn are mainly related to mining activities. The Risk Assessment Code (RAC) indicate “moderately to high risk” for mobilization of Cd, Co, Mn, Ni, Pb and Zn, while Cu and Fe indicate “low to moderate risk” for remobilization in the water column. / <p>QC 20140604</p> / Hydrochemistry: Arsenic and heavy metals in the Lake Poopó Basin (Sida contribution: 7500707606) / Catchment Management and Mining Impacts in Arid and semi-arid South America (CAMINAR) (INCO-CT-2006-032539)

In the James Bay Lowlands of northern Ontario, kimberlite pipes are concealed by peat, thick layers of till, and Tyrell sea sediments. Studies have shown that buried ore bodies produce geochemical signatures in surface media. This thesis explores the geochemistry of near-surface groundwater above concealed kimberlite pipes using factor analysis to determine whether (1) a factor analysis can reveal an underlying structure (factors) in a multivariate groundwater geochemical dataset, and whether (2) those factors are related to the presence of concealed kimberlite. Factor analysis was performed on two datasets of nearsurface groundwater, collected at 0.2 m and 1.1 m below ground surface in peat. Results revealed that (1) there is a significant difference in the behaviour of elements in groundwater near the surface compared to those in deeper groundwater, which is sheltered from the effects of the atmosphere; (2) for both datasets, the first factor is dominated by elements known to be enriched in kimberlite, notably rare earth elements (REE), U, Th, Ti – the composition of factor one is consistent with their derivation from kimberlite in a limestone background where such elements are in very low concentration; (3) high-valence and lowvalence kimberlite indicator elements (KIE) are found separated into distinct factors suggesting that once released from the kimberlite after weathering, KIE are subjected to various geochemical processes to be differentiated as they migrate upward to the surface; and (4) Fe and Mn load on a factor distinct from other metals, suggesting that in this environment Fe-Mn-O-OH is not a significant controller of metal mobility in groundwater. Overall, this research has further highlighted the multivariate nature of geochemical processes in groundwater. Compared with previous work in geochemical exploration where often only univariate or bivariate statistics or single element profiles over concealed ore bodies were used, this thesis has shown that factor analysis, as a multivariate data analysis technique, is a robust exploration tool, able to shed light on relevant geochemical processes hidden within geochemical datasets. This thesis shows that high-valence KIE, notably U,V, Th, Ti and the REE, as a group, are better indicators of the presence of kimberlites than other well-known KIE. Single element concentration profiles such as Ni or Cr (known KIE) show similar anomalies over a concealed kimberlite as a factor score profile for factor one (U, V, Th, Ti, REE, Ni) would; however, it is the peculiar assemblage of elements in factor one that makes it unique to kimberlites, a feature that can be used in future exploration work for concealed kimberlites in similar surficial environments, such as the Siberian wetlands. The results suggest that future geochemical exploration work involving groundwater should focus on the more stable groundwater located below the zone of oxidation, sheltered from the effects of the atmosphere.

The dynamics of the world's oceans occur at a vast range of length scales. Although there are theories that aid in understanding the dynamics at planetary scales and microscales, the motions in between are still not yet well understood. This work discusses a numerical model to study barotropic wind-driven gyre flow that is capable of resolving dynamics at the synoptic, O(1000 km), mesoscale, O(100 km) and submesoscales O(10 km). The Quasi-Geostrophic (QG) model has been used predominantly to study ocean circulations but it is limited as it can only describe motions at synoptic scales and mesoscales. The Rotating Shallow Water (SW) model that can describe dynamics at a wider range of horizontal length scales and can better describe motions at the submesoscales. Numerical methods that are capable of high-resolution simulations are discussed for both QG and SW models and the numerical results are compared. To achieve high accuracy and resolve an optimal range of length scales, spectral methods are applied to solve the governing equations and a third-order Adams-Bashforth method is used for the temporal discretization. Several simulations of both models are computed by varying the strength of dissipation. The simulations either tend to a laminar steady state, or a turbulent flow with dynamics occurring at a wide range of length and time scales. The laminar results show similar behaviours in both models, thus QG and SW tend to agree when describing slow, large-scale flows. The turbulent simulations begin to differ as QG breaks down when faster and smaller scale motions occur. Essential differences in the underlying assumptions between the QG and SW models are highlighted using the results from the numerical simulations.

A numerical solution algorithm based on finite volume method is developed for unsteady, two-dimensional, depth-averaged shallow water flow equations. The model is verified using test cases from the literature and free surface data obtained from measurements in a laboratory flume. Experiments are carried out in a horizontal, rectangular channel with vertical solid boxes attached on the sidewalls to obtain freesurface data set in flows where three-dimensionality is significant. Experimental data contain both subcritical and supercritical states. The shallow water equations are solved on a structured, rectangular grid system. Godunov type solution procedure evaluates the interface fluxes using an upwind method with an exact Riemann solver. The numerical solution reproduces analytical solutions for the test cases successfully. Comparison of the numerical results with the experimental two-dimensional free surface data is used to illustrate the limitations of the shallow water equations and improvements necessary for better simulation of such cases.

Depuis maintenant près d’un siècle, des robots sous-marins ont été développés afin de réaliser des tâches spécifiques aux besoins des grands acteurs historiques du domaine (militaires, pétroliers, câbliers ou explorateurs benthiques) sans vraiment se soucier de la polyvalence et de la modularité de la plateforme. L’objectif de cette thèse est d’avoir une réflexion sur une solution technologique et scientifique avec comme domaine applicatif l’environnement faible fond ou confiné. Il s’agit en d’autres termes de concevoir un robot sous-marin que l’on peut faire évoluer aisément tant sur le plan mécanique, électronique qu’informatique. Cet objectif impose de proprement conceptualiser cette « polyvalence » en s’attachant à apporter de l’abstraction dans l’architecture de contrôle que se soit au niveau de l’automatique avec l’expression de la polyvalence liée à l’étage d’actionnement ou de l’informatique avec une architecture basée services, pouvant être composés, afin de répondre à la diversité des besoins applicatifs. L’ensemble de ces travaux a pour point de départ le robot Jack mis au point par l’entreprise Ciscrea, partenaire industriel, qui apporte un aspect économique à la nécessité de développer une solution polyvalente pouvant être décliné en une gamme de produits. Ce manuscrit traite de la conception, la réalisation et l’expérimentation de ce vecteur que ce soit en piscine où en environnement réel. / Since almost a century, underwater robots have been developed in order to respond to the specific needs of historical actors of the domain (military, hydrocarbons exploitation, underwater cabling or benthic exploration), without addressing specifically the question of versatility or modularity of the underwater platform. This thesis aims to address these questions on a technological solution dedicated to shallow water or confined environment. In other words, the objective is to realise an underwater system, able to evolve on the mechanical, electronical or software aspects. This requires to properly conceptualise this « versatility » with an abstraction of the control architecture, on the actuation aspect, with the expression of the versatility linked to the actuation systems, or on the software architecture level, with a Service-Oriented-Architecture (SOA) approach, in order to tackle the diversity of the application requirements. This study is based on the Jack system, developed by the Ciscrea Company, which is the industrial partner of this project, and brings the economical aspect as a central requirement. This underlines another view of the versatility question, the development of a range of product for the Ciscrea Company.This thesis proposes the conception, realisation and experimentation of such a versatile underwater system, with test-tank and field validation.

Introdução: Extubação é a retirada da via aérea artificial. Desmame é o processo de transição da ventilação artificial para a respiração espontânea. A falha na extubação exerce um impacto adverso na clínica dos pacientes, além disso, a reintubação acrescenta dias no CTI (Centro de Terapia Intensiva) e na permanência hospitalar. O Índice de respiração rápida e superficial (IRRS) é um parâmetro fidedigno nas referências sobre o tema, devendo ser incluído em protocolos de desmame. Objetivos: Avaliar a capacidade do IRRS como preditor de sucesso de extubação da ventilação mecânica invasiva (VMI), em uma população geral de pacientes críticos e também relacionar este índice a uma população de pacientes subdivididos em diferentes comorbidades, tais como: Doentes neurológicos, cardíacos, pulmonares e outras. Material e Métodos: Foram incluídos neste trabalho pacientes que necessitaram de ventilação mecânica invasiva por um período maior que 48 horas e que foram considerados aptos para extubação pela equipe médica assistente. Foram excluídos pacientes que não fossem extubados em até 6 horas após ventilação espontânea em tubo T, paciente com traqueostomia e com doença neuromuscular periférica. Após, o paciente era colocado em ventilação espontânea com tubo T , e em seguida era registrada a relação f/Vt (freqüência respiratória/volume corrente) sendo esta calculada no 1º (IRRS 1) e 30o (IRRS 2) minuto do teste, e calculado o Delta do IRRS. Os dados foram expressos em freqüência e percentual, média e desvio padrão e mediana (percentil 25-percentil 75), com nível de significância p<0,05 e curvas ROC (Receiver-operating Characteristic) para as variáveis do IRRS. Resultados: De um total de 504 pacientes extubados, 403 (80,0%) obtiveram sucesso no processo de desmame da VMI e 101 (20,0%) falharam. Quando comparamos o grupo sucesso com o grupo insucesso, encontramos os seguintes resultados: Média de idade 56 versus 61 (p<0,025) , IRRS 1 56,5 versus 68,6 (p=0,004), IRRS 2 59,8 versus 81,8 (p=< 0,001), Delta do IRRS 3,4 versus 13,2 (p=0,011), dias de CTI 12 versus 16 (p=0,001), dias de hospitalização 29,5 versus 33 (p=0,185), óbito 11% versus 29% (p< 0,001 ). Em relação às curvas ROC encontramos os seguintes valores para as áreas sobre a curva IRRS 1- 0,592 (IC 95% 0,527 – 0,656) p=0,005; IRRS 2- 0,619 (IC 95% 0,552 – 0,686) p=< 0,001; Delta do IRRS- 0,567 (IC 95% 0,499 – 0,635) p=0,039. Não encontramos diferenças significativas quando analisamos os dados dividindo os pacientes por subgrupos de comorbidades. Conclusão: A utilização do IRRS como preditor de sucesso, pode colaborar para a identificação dos pacientes que terão sucesso no processo de extubação da ventilação mecânica invasiva. Este índice não deve ser usado isoladamente, mas deve ser incluído em protocolos de desmame. Não encontramos diferenças significativas no comportamento do IRRS nas diferentes comorbidades avaliadas neste estudo. / Introduction: Extubation is the removal of artificial airway. Weaning is the process of transition from artificial to spontaneous breathing. Extubation failure has an adverse impact on patients' clinical evolution; furthermore, re-intubation increases ICU (Intensive Care Unit) and hospitalization time. Rapid Shallow Breathing Index (RSBI) is a reliable parameter in references on the theme and should be included in weaning protocols. Objectives: To assess the capacity of RSBI as a predictor of successful extubation from invasive mechanical ventilation (IMV) in a general population of critical patients, and relate that rate to a population of patients subdivided into different co-morbidities such as neurological, cardiac, pulmonary patients and others. Material and Methods: This study includes patients who required invasive mechanical ventilation for a period of more than 48 hours and were deemed fit for extubation by the assistant medical team. It excluded patients who were not extubated within 6 hours after spontaneous ventilation with a T-piece, patients with tracheostomy and those with peripheral neuromuscular disease. After extubation, the patient was placed in spontaneous ventilation with T-piece, and then the f/Vt (respiratory rate/Tidal volume) ratio was recorded, calculated at the 1st (RSBI 1) and 30th (RSBI 2) minute of the trial and calculated Delta RSBI. The data are expressed in frequency and percentage, average, standard deviation, and median (25th percentile-75th percentile), with a significance level of p<0.05 and ROC (Receiver-operating Characteristic) curves for the variables of RSBI. Results: From a total of 504 patients extubated, 403 (80.0%) achieved successful extubation from IMV and 101 (20.0%) failed. When comparing the success group and the failure group, the following results are found: average age 56 versus 61 (p<0.025); RSBI 1 56.5 versus 68.6 (p=0.004); RSBI 2 59.8 versus 81.8 (p=< 0.001); Delta RSBI 3.4 versus 13.2 (p=0.011); days in ICU 12 versus 16 (p=0.001); days of hospitalization 29.5 versus 33 (p=0.185); death 11% versus 29% (p< 0.001 ). In relation to ROC curves we find the following values for the areas under the curve RSBI 1- 0,592 (IC 95% 0,527 – 0,656) p=0,005; RSBI 2- 0,619 (IC 95% 0,552 – 0,686) p=< 0,001; Delta RSBI- 0,567 (IC 95% 0,499 – 0,635) p=0,039. No significant differences were found when the data was analyzed dividing the patients into co-morbidity subgroups. Conclusion: The use of the RSBI as a predictor of success, can help identify patients who will succeed in extubation from invasive mechanical ventilation. This index should not be used alone, but should be included in the weaning protocols. No significant differences were found in RSBI behavior for different co-morbidities assessed in this study.

Este estudo foi realizado com base em coletas sazonais no período de um ano (2010-2011), em três pontos na Lagoa do Peixe e um ponto na Lagoa do Ruivo, lagoa à montante, com objetivo de avaliar a existência de padrões espaciais e/ou sazonais na estrutura fitoplanctônica. Este ambiente lagunar subtropical está incluso no Parque Nacional da Lagoa do Peixe (sul do Brasil) e é conectado ao Oceano Atlântico por uma barra de areia localizada na porção central da laguna. A salinidade variou amplamente de condições limnéticas à euhalinas, sendo observada em média, salinidade mais baixa no inverno, e mais elevada no verão, exceto na Lagoa do Ruivo no verão, que mostrou tendência oposta. Em relação à espacialidade, a salinidade apresentou tendência à um gradiente crescente dos pontos extremos da laguna em direção a barra, apresentando menor variação nesta (mesohalino à euhalino). A comunidade fitoplanctônica esteve formada por sete classes com 136 táxons genéricos à infra-específicos. A densidade variou de 653 a 114.829 ind.mL-1, sendo os menores valores registrados próximos a barra. Os grupos abundantes em relação a densidade foram as cianobactérias e diatomáceas. A biomassa variou de 0,3 a 24,1 mg.L-1, sendo o menor valor registrado no inverno e o maior no outono, ambos próximo a barra. A elevada biomassa no outono ocorreu devido o predomínio de euglenofíceas. Espacialmente, a Lagoa do Ruivo (menor salinidade) apresentou maior riqueza. O grupo das diatomáceas apresentou a maior riqueza total. Análises de ordenação (ACP, RDA e ACC) para verificação de tendências sazonais e/ou espaciais foram realizadas, sugerindo existência de tendências a padrões, tanto sazonais, quando espaciais na estrutura e distribuição fitoplanctônica do sistema lagunar da Lagoa do Peixe, onde a salinidade foi a variável que contribui para estes gradientes. / This study was based on seasonal sampling during one year (2010-2011) at three points in Peixe Lagoon and one point in Ruivo Lagoon, located upstream, to evaluate the spatial and seasonal patterns of phytoplankton communities. These subtropical lagoon environments are included in the National Park of Peixe Lagoon (southern Brazil) and are connected to the Atlantic Ocean by a sand bar located at the central portion of the lagoon. Salinity ranged widely from limnetic to euhaline conditions, on average from lower salinity in winter to higher in summer being observed, except at Ruivo Lagoon in summer, which showed an opposite trend. Regarding spatiality, salinity tended to an increasing gradient from extreme points of the lagoon toward the bar, with less variation at this points (mesohaline to euhaline). The phytoplankton taxonomic community was composed of seven classes with 136 generic to infraspecific taxa. Density ranged from 653 to 114,829 ind.mL-1, with the lowest values recorded near the bar. The most abundant groups in density were cyanobacteria and diatoms. Biomass ranged from 0.3 to 24.1 mg.L-1, with the lowest value recorded in winter and higher, in the fall, both near the bar. The high biomass in fall was due to the predominance of euglenoids. Spatially, the Ruivo Lagoon (lower salinity) showed greater richness. Diatoms groups showed the highest total richness. Ordination analysis (PCA, RDA and CCA) were performed, suggesting the existence seasonal and spatial patterns in relation to the structure and distribution in phytoplankton of this lagoon system, where salinity was the variable that most contributed to these gradients.