<p><font face="Helvetica"> <p align="left">The objectives of this study were:&nbsp / To review and understand flow and transport processes in unsaturated zones. In this study, particular emphasis is placed on understanding mechanisms that cause non-uniform (preferential) flow for two casestudies, namely the Cape Flats sandy environment and the Mpumalanga Highveld fractured rock environment.&nbsp / To evaluate the adequacy of models, in particular MACRO 5.0, in simulating flow and transport in the vadose zone, by making use of two case study sites (Cape Flats and Mpumalanga Highveld). Of particular importance is the evaluation of transfer coefficients to represent fluid and solute exchange between macropores and matrix.&nbsp / To run a sensitivity analysis with MACRO 5.0 in order determine which input model parameters are the most relevant in describing the effects of preferential flow in water and solute transport.</p> </font></p>

A computational fluid dynamics model has been developed to examine the separation of an oil film from a spherical oil-coated particle falling through quiescent water due to gravity. Using this model, the separation process was studied as a function of the viscosity ratio of oil to water, R, and the ratio of viscous forces to surface tension, represented by the Capillary number Ca. The governing equations of this flow-induced motion are derived in a non-inertial spherical coordinate system, and discretized using a finite volume approach. The Volume-of-Fluid method is used to capture the oil/water interface. The model predicts two mechanisms for oil separation: at R less than 1, the shear difference between the particle/oil interface and the oil/water interface is not significant and Ca determines whether separation occurs or not; at R larger than 1, the shear difference is considerable, and the Ca effect becomes less dominant.

No description available.

The inadvertent ingestion of contaminated soil is the dominant exposure route of non-volatile and semi-volatile contaminants such as polycyclic aromatic hydrocarbons (PAHs). Quantitative mass balance soil ingestion studies have been used to determine soil ingestion rates for use in human health risk assessments (HHRA) that can be used to predict the likelihood of adverse effects in individuals exposed to hazardous contaminants such as PAHs in contaminated soil. The Cold Lake region of Alberta is one of the three major oil sands regions of Alberta, and PAH concentrations in this oil sand region may be elevated in the atmosphere and the soil, resulting in increased exposures to PAHs. The area is home to Cold Lake First Nation who practice traditional activities and lifestyles that may put them in greater contact with soil than previous soil ingestion studies suggest. The primary objective of this research was to assess the soil ingestion rate in a group of First Nations subjects inhabiting the Cold lake region, and assess the carcinogenic risk posed by exposures to PAHs in air and soil. The study employed a quantitative mass balance tracer approach to estimate soil ingestion rates, and followed 9 subjects over a 13 day period. Soil and air samples were simultaneously collected to assess PAH contamination. The mean soil ingestion rate using Al and Si elemental tracers was 52 mg d-1, with a 90th percentile of 220 mg d-1, and a median soil ingestion rate of 37 mg d-1. These values are greater than the soil ingestion rates for HHRA recommended by Health Canada. The mean increase in excess lifetime cancer risk posed by inadvertent ingestion of soil to a First Nations’ individuals following traditional activities was 0.02 cases per 100,000 people with a 95% risk level of 0.067 cases per 100,000 people. Exposure to PAHs through inhalation posed a maximum lifetime cancer risk below 0.1 cases per 100,000, people. Thus, this study found no appreciable increase in excess lifetime associated with PAH exposure of First Nations’ people in the Cold Lake region.

Several studies were undertaken by various investigators during the last five decades to better understand the engineering behaviour of unsaturated soils. These studies are justified as more than 33% of soils worldwide are found in either arid or semi-arid regions with evaporation losses exceeding water infiltration. Due to this reason, the natural ground water table in these regions is typically at a greater depth and the soil above it is in a state of unsaturated conditions. Foundations of structures such as the housing subdivisions, multi-storey buildings, bridges, retaining walls, silos, and other infrastructure constructed in these regions in sandy soils are usually built within the unsaturated zone (i.e., vadose zone). Limited studies are reported in the literature to understand the influence of capillary stresses (i.e., matric suction) on the bearing capacity, settlement and liquefaction potential of unsaturated sands. The influence of matric suction in the unsaturated zone of the sandy soils is ignored while estimating or evaluating bearing capacity, settlement and liquefaction resistance in conventional engineering practice. The focus of the research presented in the thesis has been directed towards better understanding of these aspects and providing rational and yet simple tools for the design of shallow foundations (i.e., footings) in sands under both static and dynamic loading conditions. Terzaghi (1943) or Meyerhof (1951) equations for bearing capacity and Schmertmann et al. (1978) equation for settlement are routinely used by practicing engineers for sandy soils based on saturated soil properties. The assumption of saturated conditions leads to conservative estimates for bearing capacity; however, neglecting the influence of capillary stresses contributes to unreliable estimates of settlement or differential settlement of footings in unsaturated sands. There are no studies reported in the literature on how capillary stresses influence liquefaction, bearing capacity and settlement behavior in earthquake prone regions under dynamic loading conditions. An extensive experimental program has been undertaken to study these parameters using several specially designed and constructed equipment at the University of Ottawa. The influence of matric suction, confinement and dilation on the bearing capacity of model footings in unsaturated sand was determined using the University of Ottawa Bearing Capacity Equipment (UOBCE-2011). Several series of plate load tests (PLTs) were carried out on a sandy soil both under saturated and unsaturated conditions. Based on these studies, a semi-empirical equation has been proposed for estimating the variation of bearing capacity with respect to matric suction. The saturated shear strength parameters and the soil water characteristic curve (SWCC) are required for using the proposed equation. This equation is consistent with the bearing capacity equation originally proposed by Terzaghi (1943) and later extended by Meyerhof (1951) for saturated soils. Chapter 2 provides the details of these studies. The cone penetration test (CPT) is conventionally used for estimating the bearing capacity of foundations because it is simple and quick, while providing continuous records with depth. In this research program, a cone penetrometer was specially designed to investigate the influence of matric suction on the cone resistance in a controlled laboratory environment. Several series of CPTs were conducted in sand under both saturated and unsaturated conditions. Simple correlations were proposed from CPTs data to relate the bearing capacity of shallow foundations to cone resistance in saturated and unsaturated sands. The details of these studies are presented and summarized in Chapter 3. Standard penetration tests (SPTs) and PLTs were conducted in-situ sand deposit at Carp region in Ottawa under both saturated and unsaturated conditions. The test results from the SPTs and PLTs at Carp were used along with other data from the literature for developing correlations for estimating the bearing capacity of both saturated and unsaturated sands. The proposed SPT-CPT-based technique is simple and reliable for estimation of the bearing capacity of footings in sands. Chapter 4 summarizes the details of these investigations. Empirical relationships were proposed using the CPTs data to estimate the modulus of elasticity of sands for settlement estimation of footings in both saturated and unsaturated sands. This was achieved by modifying the Schmertmann et al. (1978) equation, which is conventionally used for settlement estimations in practice. Comparisons are provided between the three CPT-based methods that are commonly used for settlement estimations in practice and the proposed method for seven large scale footings in sandy soils. The results of the comparisons show that the proposed method provides better estimations for both saturated and unsaturated sands. Chapter 5 summarizes the details of these studies. A Flexible Laminar Shear Box (FLSB of 800-mm3 in size) was specially designed and constructed to simulate and better understand the behaviour of model surface footing under seismic loads taking account of the influence of matric suction in an unsaturated sandy soil. The main purpose of using the FLSB is to simulate realistic in-situ soils behaviour during earthquake ground shaking. The FLSB test setup with model footing was placed on unidirectional 1-g shake table (aluminum platform of 1000-mm2 in size) during testing. The resistance of unsaturated sand to deformations and liquefaction under seismic loads was investigated. The results of the study show that matric suction offers significant resistance to liquefaction and settlement of footings in sand. Details of the equipment setup, test procedure and results of this study are presented in Chapter 6. Simple techniques are provided in this thesis for estimating the bearing capacity and settlement behaviour of sandy soils taking account of the influence of capillary stresses (i.e., matric suction). These techniques are consistent with the methods used in conventional geotechnical engineering practice. The studies show that even low values of capillary stresses (i.e., 0 to 5 kPa) increases the bearing capacity by two to four folds, and the settlement of footings not only decreases significantly but also offers resistance to liquefaction in sands. These studies are promising and encouraging to use ground improvement techniques; such as capillary barrier techniques to maintain capillary stresses within the zone of influence below shallow foundations. Such techniques, not only contribute to the increase of bearing capacity, they reduce settlement and alleviate problems associated with earthquake effects in sandy soils.

This thesis consists of three essays on risk management in crude oil markets. In the first essay, the valuation of an oil sands project is studied using real options approach. Oil sands production consumes substantial amount of natural gas during extracting and upgrading. Natural gas prices are known to be stochastic and highly volatile which introduces a risk factor that needs to be taken into account. The essay studies the impact of this risk factor on the value of an oil sands project and its optimal operation. The essay takes into account the co-movement between crude oil and natural gas markets and, accordingly, proposes two models: one incorporates a long-run link between the two markets while the other has no such link. The valuation problem is solved using the Least Square Monte Carlo (LSMC) method proposed by Longsta ff and Schwartz (2001) for valuing American options. The valuation results show that incorporating a long-run relationship between the two markets is a very crucial decision in the value of the project and in its optimal operation. The essay shows that ignoring this long-run relationship makes the optimal policy sensitive to the dynamics of natural gas prices. On the other hand, incorporating this long-run relationship makes the dynamics of natural gas price process have a very low impact on valuation and the optimal operating policy. In the second essay, the relationship between the slope of the futures term structure, or the forward curve, and volatility in the crude oil market is investigated using a measure of the slope based on principal component analysis (PCA). The essay begins by reviewing the main theories of the relation between spot and futures prices and considering the implication of each theory on the relation between the slope of the forward curve and volatility. The diagonal VECH model of Bollerslev et al. (1988) was used to analyse the relationship between of the forward curve slope and the variances of the spot and futures prices and the covariance between them. The results show that there is a significant quadratic relationship and that exploiting this relation improves the hedging performance using futures contracts. The third essay attempts to model the spot price process of crude oil using the notion of convenience yield in a regime switching framework. Unlike the existing studies, which assume the convenience yield to have either a constant value or to have a stochastic behaviour with mean reversion to one equilibrium level, the model of this essay extends the Brennan and Schwartz (1985) model to allows for regime switching in the convenience yield along with the other parameters. In the essay, a closed form solution for the futures price is derived. The parameters are estimated using an extension to the Kalman filter proposed by Kim (1994). The regime switching one-factor model of this study does a reasonable job and the transitional probabilities play an important role in shaping the futures term structure implied by the model.

Research Project (M.R.M.) - Simon Fraser University, 2005. / Research Project (School of Resource and Environmental Management) / Simon Fraser University.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 178-191).

No Bioma Pampa, somente 4.753,42 hectares são preservados como Unidades de Conservação Estaduais oficialmente inseridas no Sistema Estadual de Unidades de Conservação. Observa-se, também, que, no Estado do Rio Grande do Sul, não existe uma unidade de conservação que represente os ecossistemas de campos com ocorrência de areais, os chamados campos de areais, locais com ocorrência de endemismo, elevado risco às espécies ali existentes e com registros arqueológicos significativos. O Código Estadual do Meio Ambiente do Estado do RS determina, em seu artigo 41, que as UC serão criadas por ato do Poder Público, sendo prioritária a criação daquelas que contiverem ecossistemas ainda não representados no SEUC, em iminente perigo de eliminação ou degradação, ou, ainda, pela ocorrência de espécies endêmicas ou ameaçadas de extinção. Tal situação ocorre nesta região do RS, uma vez que existe lacuna na conservação. Na busca por entendimento desta situação, esta dissertação aborda a indicação de áreas de relevante interesse ambiental, na região de ocorrência de campos com areais, localizadas na porção sudoeste do Rio Grande do Sul, com potencial para integrarem o Sistema Estadual de Unidades de Conservação. Tal indicação inclui o areal de Quaraí/RS, área de grande beleza, com representação para a história do RS e possuidora de sítios arqueológicos. / In the Pampa biome, only 4753.42 acres are preserved as State Protected Areas officially incorporated in the State System of Conservation Units. It is noted also that the state of Rio Grande do Sul, there is a conservation unit that represents the ecosystems of fields with the occurrence of sand, called sand fields, with the occurrence of local endemism, high-risk species found there and significant archaeological records. The State Environmental Code of the State of RS stipulates in its article 41 that the UC will be created by an act of the public, with priority to create ecosystems that contain those not yet represented in SEUC, or in imminent danger of elimination or degradation, or Furthermore, the occurrence of endemic or endangered. This situation occurs in this region RS, since there is gap conservation. In the search for understanding of this situation, this paper discusses the appointment of the relevant areas of environmental concern in the region of occurrence of fields with sandy beaches, located in the southwestern portion of Rio Grande do Sul, with the potential to integrate the State System of Conservation Units. Such indications include the sands of Quarai / RS, an area of great beauty, with representation in the history of RS and owner of archaeological sites.

A adoção de técnicas de melhoramento de solos é prática cada vez mais recorrente em obras geotécnicas, contudo, os critérios de dosagem e parâmetros de previsão do comportamento desses solos parecem não acompanhar a evolução tecnológica das referidas técnicas. O parâmetro de estado para areias (ψ) não consegue representar o comportamento de areias artificialmente cimentadas, por levar em consideração apenas a influência do índice de vazios e do estado de tensões. Propõe-se, neste estudo, instituir o índice porosidade/teor volumétrico de cimento (η/Civ) como um parâmetro de estado para areias artificialmente cimentadas, por ser um critério racional que relaciona a porosidade da mistura compactada com o teor volumétrico de cimento adicionado. A partir da utilização desse parâmetro, é possível calibrar a quantidade de cimento e a energia de compactação utilizada, a fim de proporcionar uma mistura que atenda aos requisitos de projeto e que seja viável de executar em obra com os recursos materiais e financeiros disponíveis. O programa experimental compreendeu a realização de 17 ensaios triaxiais, drenados e não drenados, analisados em conjunto com resultados já obtidos em estudos anteriores. Análises do comportamento tensão-deformação, variação volumétrica-deformação axial, geração de poropressão, trajetórias de tensões drenadas e não drenadas, envoltórias de resistência, comportamento tensão-dilatância, da aplicação da teoria do estado crítico e uma breve análise estatística embasaram a comprovação de que o parâmetro η/Civ é adequado para previsão do comportamento de corpos de prova de areia artificialmente cimentados. / The adoption of soil improvement techniques is becoming more frequent in geotechnical works, however, the dosage criteria and the parameters used to predict the soil behavior do not seem to follow the technological evolution of these techniques. The state parameter for sands (ψ) cannot represent the behavior of artificially cemented sands because it considers only the influence of the void ratio and the stress state. It is proposed to establish the porosity/volumetric content of cement (η/Civ) as a state parameter for artificially cemented sands, since it is a rational criterion which relates the porosity of the compacted mixture to the volumetric content of cement added. By using this parameter, it is possible to calibrate the amount of cement and the compaction energy used in order to provide a mixture that meets the design requirements and that is feasible to perform on site construction with the material and financial resources available there. The experimental program included the realization of 17 triaxial testes, performed in the drained and undrained conditions, analyzed simultaneously with other results obtained from previous studies. Analysis of stress-strain behavior, volumetric variation-axial strain, pore pressure development, drained and non-drained stress paths, resistance envelope, stress-dilatation behavior, the application of the critical state theory, and a brief statistical analysis supported that the η/Civ parameter is suitable for predicting the behavior of artificially cemented sand specimens.