Stochastic analysis of flow and salt transport modeling in irrigation-drainage systems

2012 Spring.Includes bibliographical references.Sustainability of crop production in the Lower Arkansas River Basin in Colorado is seriously threatened by the continuous degradation of irrigated lands by the dual impact of soil salinization and waterlogging problems. Integration of improved irrigation practices, upgrades to the irrigation systems, and subsurface drainage are essential components of any plan to stop the deterioration of irrigated lands. Numerical simulations of irrigation and drainage systems are necessary to justify the consequent management actions. Despite the uncertainty of their predictions, numerical models are still indispensable decision support tools to investigate the feasibility of irrigation and drainage systems management plans. However, the uncertainties in input parameters to these models create a risk of misleading numerical results. That is beside the fact that the numerical models themselves are conceptual simplifications of the complex reality. The overarching objective of this dissertation is to investigate the impact of parameters uncertainty on the response of simulated irrigation-drainage systems. In the first part of the research, a Global Sensitivity Analysis (GSA) is conducted using a one-dimensional variably saturated problem to prioritize parameters according to their importance with respect to predefined performance indices. A number of GSA methods are employed for this purpose, and their comparative performances are investigated. Results show that only five parameters out of 18 parameters are responsible for around 73% of crop yield uncertainty. The second part introduces a method to reduce the computational requirements of Monte Carlo Simulations. Numerical simulation of variably saturated three-dimensional fields is typically a computationally intensive process, let alone Monte Carlo Simulations of such problems. In order to reduce the number of model evaluations while producing acceptable estimates of the output statistical properties, Cluster Analysis (CA) is used to group the input parameter realizations, e.g. hydraulic conductivity. The potentials of this approach are investigated using different: 1) clustering schemes; 2) clustering configurations, and 3) subsampling schemes. . Results show that response of 400 realizations ensemble can be efficiently approximated using selected 50 realizations. The third part of the research investigates the impact of input parameter uncertainty on the response of irrigation-drainage systems, particularly on crop yield and root zone hydrosalinity. The three-dimensional soil parameters, i.e. hydraulic conductivity, porosity, the pore size distribution (van Genuchten β) parameter, the inverse of the air entry pressure (van Genuchten α) parameter, the residual moisture content parameter, and dispersivity; are treated as spatial random processes. A sequential multivariate Monte Carlo simulation approach is implemented to produce correlated input parameter realizations. Other uncertain parameters that are considered in the study are irrigation application variability, irrigation water salinity, irrigation uniformity, preferential flow fraction, drain conductance coefficient, and crop yield model parameters. Results show that as the crop sensitivity to salinity increases, the crop yield standard deviation increases. The fourth part of the research investigates an approach for optimal sampling of multivariate spatial parameters in order to reduce their uncertainty. The Ensemble Kalman Filter is used as instrumentation to integrate the sampling of the hydraulic conductivity and the water level for a two-dimensional steady state problem. The possibility of combining designs for efficient prediction and for efficient geostatistical parameter estimation is also investigated. Moreover, the effect of relative prices of sampled parameters is also investigated. A multi-objective genetic algorithm is employed to solve the formulated integer optimization problem. Results reveal that the multi-objective genetic algorithm constitutes a convenient framework to integrate designs that are efficient for prediction and for geostatistical parameter estimation

AGU hydrology days 2011

2011 annual AGU hydrology days was held at Colorado State University on March 21 - March 23, 2011.Includes bibliographical references.Spatial heterogeneity of soil properties and uncertainty in root uptake model parameters make the numerical prediction of crop yield prone to a high degree of uncertainty. In this study, the spatial soil parameters are treated as multivariate correlated regionalized random parameters. Sequential indicator simulation is used to generate three-dimensional dependant realizations for hydraulic conductivity, porosity, Van Genuchten parameters and dispersivity. Other semi empirical parameters that control crop water uptake and subsurface drainage conductance where also randomized. Four hundred realizations for each of the soil parameters were generated and processed in the variably saturated flow and transport model (CSUID) to obtain the spatial statistical moments of the relative crop yield, root zone salinity and salt leaching fraction. The statistical distributions of drainage flow and salinity hydrographs were also calculated. Results show that parameter uncertainty significantly affects in-field relative crop yield variability and drainage flow and salinity effluent

O processo de produção do conhecimento nos PPGs de teologia

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Educação. Programa de Pós-Graduação em Educação.Nesta tese, o objetivo foi investigar as induções geradas pelo sistema de avaliação e fomento da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes) nos processos de produção de conhecimento dos Programas de Pós-graduação em Teologia (PPGTs). Problematizou-se a influência dos critérios de avaliação da Capes nos processos de produção do conhecimento no campo epistemológico da Teologia, tendo como aporte teórico o conceito de #campo# de Bourdieu. Para análise, foi realizado estudo de caso múltiplo em três Programas de Pós-graduação em Teologia com conceitos iguais ou superiores a cinco e que ofereciam cursos de mestrado e doutorado reconhecidos pelas suas igrejas # católica ou protestante #, em período anterior à inserção no sistema Capes. A metodologia envolveu entrevistas e coleta de dados em documentos disponibilizados pela Capes e pelos PPGTs. As entrevistas foram realizadas com dois grupos: dez pesquisadores da área da Teologia não vinculados aos PPGT em análise, com o objetivo de obter umolhar privilegiado sobre o campo de conhecimento teológico, e um segundo, composto por doze professores, quatro de cada PPGT em análise, sendo o critério de escolha: o tempo de vinculação ao PPGT; ter atuação antes e depois da inserção na Capes. A coleta de dados teve como base os documentos: fichas de avaliação dos PPGTs emitidas pela Capes; proposta dos PPGT em análise; produção docente e discente veiculada nos currículos lattes; análise das publicações nas revistas científicas dos PPGT pesquisados. Os resultados da pesquisa apontam que a inserção no Sistema de avaliação e fomento exigiu dos PPGTs mudanças, estruturais e epistemológicas, tais como: alterações nas linhas de pesquisa, nas teses e dissertações, bem como transformações nos tempos e meios de veiculação da produção docente. Foi constatado como um paradigma avaliativo pode afetar um determinado campo de conhecimento, causando uma inflexão epistemológica, principalmente quando os PPGTs buscam alcançar o topo do ranking do Sistema Capes. Há uma zona de tensão entre a produção do conhecimento religioso e as determinações indutoras do organismo de avaliação, regulação e financiamento da pós-graduação no Brasil. Há evidências de uma reconstrução e reconfiguração do campo de produção do conhecimento teológico nos Programas de Pósgraduação em Teologia analisados na busca de adaptação aos critérios de avaliação da Capes. Os entrevistados apontaram e analisaram os ganhos, perdas e embates decorrentes desse processoThe purpose of this thesis was to investigate the changes generated by the evaluation and finance system of the Coordination for Personnel Improvement in Higher Education (CAPES) in the processes of production of knowledge of graduate theology programs (PPGTs). It analyzed the influence of CAPES# evaluation criteria on the processes of knowledge production in the epistemological field of Theology. The theoretical support for the study was Bourdieu#s concept of #field.# A multiple case study was conducted at three graduate theology programs that received grades equal or higher than 5 and that offered masters and doctoral courses recognized by their churches # Catholic or Protestant # in a period previous to their insertion in the CAPES system. The methodology involved interviews and data collection from documents provided by Capes and by the graduate programs. The interviews were conducted with two groups. The first included 10 researchers from the field of Theology not linked to the graduate programs being studied, to obtain a good look at the theological field of knowledge. The second group was composed of 12 professors, four from each graduate program being analyzed. The criteria used to select the professors was the time of their relationship with the program and whether they had worked before and after the program#s insertion in the Capes system. The data collection was based on documents, including evaluation records of the graduate programs issued by Capes; the course proposal of the program being studied; the production of students and professors as indicated in the CAPES on-line data base (lattes); and an analysis of publications in scientific journals by the graduate programs being studied. The results of the research indicate that the insertion in the evaluation and financial support system required that the graduate programs make both structural and epistemological changes. These changes included: alterations in the research lines, in the theses and the dissertations, as well as transformations in the frequency and means of presentation of the work of the professors. It was found how an evaluative paradigm could affect a given field of knowledge, causing an epistemological inflection, mainly, when the graduate programs sought to reach the top of the Capes System ranking. There is a zone of tension between the production of religious knowledge and the inductive determinations of the agency responsible for evaluation, regulation and finance of graduate programs in Brazil. There is evidence of a reconstruction and reconfiguration of the field of production of theological knowledge in the graduate theology programs analyzed, as they sought to adapt to Capes# evaluation criteria. The people interviewed indicated and analyzed the gains, losses and conflicts related to this proces

Modeling spatial and temporal variability

Presented at the fifth international conference on irrigation and drainage, Irrigation and drainage for food, energy and the environment on November 3-6, 2009 in Salt Lake City, Utah.Includes bibliographical references.The Colorado State University irrigation and drainage model (CSUID) is a three dimensional variable saturated-unsaturated numerical model that simulates the subsurface flow and transport processes. A wide range of enhancements have been done to CSUID to fully simulate the response of agricultural fields to external stresses such as subsurface drainage systems, root extractions and irrigation activities. The model is also capable of simulating salinity transport process through the vadose zone and in the saturated zone. The partition of salinity between the soil solid phase and the water phase is included in the model to simulate the accumulation of salts in the root zone. The strength of CSUID is in its ability to simulate irrigation-drainage activities taking into account spatially and temporal variably in water quality and quantity and under spatial heterogeneous soil properties. Soil properties such as hydraulic conductivity, porosity, Van Genutchen retention curve parameters, storativity, dispersivity, partition coefficients are all modeled as spatially variables. Having a model with these capabilities is an important step toward understanding the uncertainty in the design and management of irrigation-drainage systems. The model contains a Graphical User Interface that allows the user to visualize the input and output

Guicciardini on diplomacy Selections from the Ricordi

SIGLEAvailable from British Library Document Supply Centre-DSC:3589.3815(38) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Stochastic and global sensitivity analyses of uncertain parameters affecting the safety of geological carbon storage in saline aquifers of the Michigan Basin

Geological carbon storage (GCS) has been proposed as a favorable technology to reduce carbon dioxide (CO2) emissions to the atmosphere. One of the main concerns about GCS is the risk of CO2 escape from the storage formation through leakage pathways in the sealing layer. This study aims at understanding the main sources of uncertainty affecting the upward migration of CO2 through pre-existing “passive” wells and the risk of fissuring of target formation during GCS operations, which may create pathways for CO2 escape. The analysis focuses on a potential GCS site located within the Michigan Basin, a geologic basin situated on the lower Peninsula of the state of Michigan. For this purpose, we perform a stochastic analysis (SA) and a global sensitivity analysis (GSA) to investigate the influence of uncertain parameters, such as: permeability and porosity of the injection formation, passive well permeability, system compressibility, brine residual saturation, and CO2 end-point relative permeability. For the GSA, we apply the extended Fourier amplitude sensitivity test (FAST), which can rank parameters based on their direct impact on the output, or first-order effect, and capture the interaction effect of one parameter with the others, or higher-order effect. To simulate GCS, we use an efficient semi-analytical multiphase flow model, which makes the application of the SA and the GSA computationally affordable. Results show that, among model parameters, the most influential on both fluid overpressure and CO2 mass leakage is the injection formation permeability. Brine residual saturation also has a significant impact on fluid overpressure. While influence of permeability on fluid overpressure is mostly first-order, brine residual saturation’s influence is mostly higher-order. CO2 mass leakage is also affected by passive well permeability, followed by porosity and system compressibility through higher-order effects