Cette recherche vise à étudier les impacts environnementaux d'une technologie émergente de production d’électricité basée sur une source renouvelable, les systèmes géothermiques stimulés (EGS), par l’analyse de leur cycle de vie (ACV).Après avoir analysé plusieurs études de cas, nous avons développé un modèle ACV paramétré capable de caractériser les performances environnementales de la filière EGS. Nos résultats montrent que les émissions de gaz à effet de serre des EGS sur leur cycle de vie sont bien inférieures à celles des centrales utilisant des combustibles fossiles.Dans un deuxième temps, nous avons mis au point un cadre méthodologique pour appliquer l'analyse de sensibilité globale (GSA) à l’ACV des technologies émergentes comme les EGS, prenant en compte les incertitudes élevées liées à leur caractère innovant. Nous avons appliqué notre nouvelle approche GSA pour développer un modèle ACV simplifié, à destination des décideurs, permettant une estimation rapide des impacts des EGS à partir de seulement cinq paramètres clefs: capacité installée, profondeur de forage, nombre de puits, débit géothermal et durée de vie.L'approche méthodologique développée dans cette thèse est applicable à d'autres technologies et ouvre de larges perspectives de recherche dans le domaine de l'évaluation environnementale. / This thesis investigates the environmental impacts of an emerging renewable energy technology, the enhanced geothermal systems (EGS), using a life cycle assessment (LCA) approach.Following the analysis of several EGS case studies, we developed a parameterized LCA model able to provide a global overview of the life cycle impacts of the EGS technology. The greenhouse gas emissions of EGS are found comparable with other renewable energy systems and far better than those of power plants based on fossil fuels.In a second stage, we developed a methodological framework for the application of global sensitivity analysis (GSA) to the LCA of emerging technologies like the EGS, taking into account the high uncertainties related to their description. We applied our new GSA approach to generate a simplified LCA model, aimed at decision makers, allowing a rapid estimation of the life cycle impacts of EGS from only five key parameters: installed capacity, drilling depth, number of wells, flow rate and lifetime.The methodological approach developed in this thesis is applicable to other technologies and opens large research perspectives in the field of environmental assessment.

This thesis provides a novel investigation into rainfall-runoff processes occurring within a unique two-tiered depth-driven overland flow physical modelling environment, as well as within a numerical model context where parameterisation and DEM/building resolution influences have been investigated using an innovative de-coupled methodology. Two approaches to simulating urban rainfall-runoff responses were used. Firstly, a novel, 9 m2 physical modelling environment consisting of a: (i) a low-cost rainfall simulator component able to simulate consistent, uniformly distributed rainfall events of varying duration and intensity, and; (ii) a modular plot surface layer was used. Secondly, a numerical hydroinundation model (FloodMap2D-HydroInundation) was used to simulate a short-duration, high intensity surface water flood event (28th June 2012, Loughborough University campus). The physical model showed sensitivities to a number of meteorological and terrestrial factors. Results demonstrated intuitive model sensitivity to increasing the intensity and duration of rainfall, resulting in higher peak discharges and larger outflow volumes at the model outflow unit, as well as increases in the water depth within the physical model plot surface. Increases in percentage permeability were also shown to alter outflow flood hydrograph shape, volume, magnitude and timing due to storages within the physical model plot. Thus, a reduction in the overall volume of water received at the outflow hydrograph and a decrease in the peak of the flood event was observed with an increase in permeability coverage. Increases in the density of buildings resulted in a more rapid receding limb of the hydrograph and a steeper rising limb, suggesting a more rapid hydrological response. This indicates that buildings can have a channelling influence on surface water flows as well as a blockage effect. The layout and distribution of permeable elements was also shown to affect the rainfall-runoff response recorded at the model outflow, with downstream concentrated permeability resulting in statistically different hydrograph outflow data, but the layout of buildings was not seen to result in significant changes to the outflow flood hydrographs; outflow hydrographs appeared to only be influenced by the actual quantity and density of buildings, rather than their spatial distribution and placement within the catchment. Parameterisation of hydraulic (roughness) and hydrological (drainage rate, infiltration and evapotranspiration) model variables, and the influence of mesh resolution of elevation and building elements on surface water inundation outputs, both at the global and local level, were studied. Further, the viability of crowdsourced approaches to provide external model validation data in conjunction with dGPS water depth data was assessed. Parameterisation demonstrated that drainage rate changes within the expected range of parameter values resulted in considerable losses from the numerical model domain at global and local scales. Further, the model was also shown to be moderately sensitive to hydraulic conductivity and roughness parameterisation at both scales of analysis. Conversely, the parameterisation of evapotranspiration demonstrated that the model was largely insensitive to any changes of evapotranspiration rates at the global and local scales. Detailed analyses at the hotspot level were critical to calibrate and validate the numerical model, as well as allowing small-scale variations to be understood using at-a-point hydrograph assessments. A localised analysis was shown to be especially important to identify the effects of resolution changes in the DEM and buildings which were shown to be spatially dependent on the density, presence, size and geometry of buildings within the study site. The resolution of the topographic elements of a DEM were also shown to be crucial in altering the flood characteristics at the global and localised hotspot levels. A novel de-coupled investigation of the elevation and building components of the DEM in a strategic matrix of scenarios was used to understand the independent influence of building and topographic mesh resolution effects on surface water flood outputs. Notably, the inclusion of buildings on a DEM surface was shown to have a considerable influence on the distribution of flood waters through time (regardless of resolution), with the exclusion of buildings from the DEM grid being shown to produce less accurate results than altering the overall resolution of the horizontal DEM grid cells. This suggests that future surface water flood studies should focus on the inclusion and representation of buildings and structural features present on the DEM surface as these have a crucial role in modifying rainfall-runoff responses. Focus on building representation was shown to be more vital than concentrating on advances in the horizontal resolution of the grid cells which make up a DEM, as a DEM resolution of 2 m was shown to be sufficiently detailed to conduct the urban surface water flood modelling undertaken, supporting previous inundation research.

Les inondations représentent le premier danger naturel sur chaque continent, avec des préoccupations particulières centrées sur les inondations urbaines pour l'urbanisation sans précédent, qui augmente la vulnérabilité des sociétés humaines aux inondations. Pour les difficultés d'accès aux données en temps réel, la méthode numérique semble être une approche puissante pour la prévision des inondations et l'atténuation des dommages. Dans cette thèse, un nouveau logiciel Flood1D2D pour la modélisation des crues urbaines a été proposé en utilisant le maillage de couplage 1D2D, avec 1D dans la rue et 2D appliqué au carrefour. Le logiciel est conçu sur la base de l'installation située dans ICube Strasbourg et validée à l'aide de cas de tests synthétiques. La nouveauté du modèle est de rendre compte de l'effet de recirculation en utilisant la fonction de porosité, et de reproduire la convexité dans les profils de profondeur le long de la rue en aval de chaque carrefour où une zone de recirculation apparaît. Une analyse de sensibilité basée sur la variance est également réalisée pour les modèles classiques d'eau peu profonde 1D et 2D pour l'étalonnage de modèles et la collecte de données. / Flooding represents the first natural hazard on each continent, with special concerns are focused on urban flooding for the unprecedented urbanization, which increases the vulnerability of human societies to floods. For the accessing difficulties of real-time data, numerical method seems to be a powerful approach for flood forecasting and damage mitigation. In this thesis, a new software Flood1D2D for urban flood modeling has been proposed using 1D2D coupling mesh, with 1D on the street and 2D applied on the crossroad. The software is designed based on the rig located in ICube Strasbourg and validated using synthetic test cases. The novelty of the model is to account for the recirculation effect using porosity function, and it can reproduce the convexity in water depth profiles along the street downstream each crossroad where a recirculation zone appears, which can't be accounted using roughness only. Variance based sensitivity analysis is also performed for classical 1D and 2D shallow water models for model calibration and data collections.

Winter in Northern Sweden comes with very harsh and unpredictable condition associated with large amounts of snowfall covering roadways thereby affecting transportation by roads. When the road conditions i.e. the snow depth, road unevenness and friction of the road surface are accessed and found to exceed the threshold, a maintenance action must be carried out to retain the road to the required condition for the user. The aim of maintenance, in this case, is to make the road comfortable, safe and economical for the road user. Decision support system, therefore, comes in handy to facilitate on deciding what maintenance action to carry out and when the action should be carried out, where the action should be carried out and how to go about the action based on the various data and resources available. This thesis project concentrates on how to carry out a winter road maintenance after receiving an alert of an action to carry out, when to carry it out and the road network that needs to be maintained. The thesis work focusses only on two of the winter road maintenance actions namely snow ploughing of bus stops in Luleå and application of abrasives commonly referred to as sanding of bus stops. Carrying out winter road maintenance comes at a huge cost from both direct and indirect costs with the Swedish government spending about SEK 1.75 billion every year as indicated by Jana Sochor and Cecilia Yu (Sochor & Yu, 2004). This means that reduction in the maintenance cost of even 5% through optimisation of the maintenance cost would translate into a saving of about 87.5 million SEK per year and in 10 years could amount to close to 1 billion SEK. Optimization also leads to efficiency and effectiveness that could result in improved movement on the road and reduced environmental and social-economic impacts. Maintenance planning thus becomes essential for the effective and efficient execution of work and utilisation of the available scarce resource. This thesis project focusses on the use of Operations research methods to minimise the cost of carrying out a winter road maintenance action by finding the near optimal or if possible optimal solution and still deliver the required service level. The thesis delivers two main things: It first delivers a framework to support winter road maintenance decision making after an alert of an action is received and secondly an algorithm for the route that minimises the cost of maintenance by providing the route that minimises the travel distance of the ploughing/sanding vehicle from its source depot and back to the depot after completing a maintenance action assuming that the vehicle and material (fuel and sand) are in the same depot. The routes with minimum travel distance will, therefore, be that route that will reduce the labour time and in turn the labour cost, reduce the fuel consumption and the maintenance of the equipment due to reduced usage. The project uses a vehicle routing problem which is a generalised travelling Salesman as the optimisation technique to determine the optimal solution for the allocation of resources for carrying out a maintenance action to facilitate efficient utilisation of the available resources. This is with the help of a commercial optimisation software and support tools namely ArcGIS. To come up with the algorithm, the first step was a digital representation of the vehicle road network in Luleå for network analysis after which the bus stops were imported from google earth into the network. A two-stage optimisation was then carried out: first was a model for route optimisation based on the road network in ArcGIS with the objective function to minimise the travel distance and constraints based on the available resources. The results of ii the model were then exported into excel for the second optimisation for the optimal cost of maintenance done through a developed excel algorithm. The total cost of maintenance comprised direct and indirect cost. The direct cost consisted of the cost of fuel, the cost of personnel and the cost of hiring vehicles while the indirect cost results from the penalty fee charged for sanding and ploughing a bus stop after the threshold time given to a maintenance contractor by the municipality. Any bus stop that is ploughed after the threshold attracts a penalty per hour of the exceeded time. Six penalty threshold times were considered i.e. 30, 60, 90, 120, 150 and 180 minutes and a single parameter deterministic sensitivity analysis was carried out for each cost parameters to determine the sensitivity of the total maintenance cost. The more relaxed penalty thresholds were found to be less sensitive to the direct cost and the total maintenance cost compared to the more sensitive ones. When the penalty threshold is relaxed, the optimal maintenance cost reduces, and the required number of vehicles reduces. The cost of vehicle hire was found to be more sensitive than the other costs. The results of this project can help the maintenance contractor in developing a work schedule for the maintenance personnel and improve vehicle fleet management. By modelling the worst scenario, a contractor can plan for the maximum number of vehicles required and consequently the personnel required. With the optimal travel route for each vehicle and the total maintenance cost determined, maintenance contractors can determine the sustainability and profitability of their business and be able to negotiate for a better and more sustainable agreement (Contract) or for the relaxation of the penalty threshold time if it does not affect the service level required i.e. the quality and safety requirements. The approach used in this project can also be used for other winter road maintenance problems.

[pt] O presente trabalho propõe uma formulação para o projeto ótimo de pilares de edifícios altos de concreto armado. São variáveis de projeto as dimensões da seção transversal e a armadura longitudinal dos pilares e a resistência característica do concreto. A fim de reduzir o tamanho desta classe de problema, a estratégia de solução em multinível é aplicada. O problema é então subdividido em um problema global de otimização conectado a uma série de subproblemas individuais de otimização. No problema global são determinadas as dimensões da seção transversal de todos os pilares e a resistência característica do concreto, enquanto que nos subproblemas individuais são determinadas apenas as armaduras longitudinais dos pilares. As variáveis dos subsistemas são freqüentemente chamadas de variáveis locais, enquanto que as variáveis do sistema global, responsáveis pela interação entre os grupos de variáveis, são denominadas variáveis globais ou de acoplamento. A função objetivo do problema de otimização é o custo total das colunas do edifício. Os edifícios são modelados como pórticos espaciais e a não-linearidade geométrica é considerado na análise estrutural. A hipótese de diafragma rígido é adotada para o comportamento das lajes e a rigidez à torção é desprezada em todas as barras do pórtico. Cargas permanentes, acidentais e devidas ao vento são aplicadas ao modelo. Restrições relativas aos estados limite último e de utilização, bem como restrições relativas aos limites máximos e mínimos atribuídos a cada variável, são impostas ao problema de otimização. Adicionalmente, impõem-se restrição sobre o parâmetro de instabilidade, caso este parâmetro seja empregado na determinação dos esforços globais de 2a ordem. Os estados limite são definidos de acordo com o código brasileiro para projeto de estruturas de concreto NBR-6118 (2003). O problema de otimização proposto é resolvido empregando-se técnicas de programação matemática. / [en] This work proposes a formulation for the optimum design of columns of reinforced concrete tall buildings. The design variables are the dimensions of the cross-sections and the amount of longitudinal reinforcement in the columns and the concrete characteristic resistance. Aiming at reducing the size of this class of problem, the multilevel optimization technique is applied so that the problem is subdivided into a global problem connected with a series of dependent subproblems. In this kind of problem, the design variables are subdivided into two groups, namely, the group of the so called global variables, represented here by the cross-section dimensions of the columns and by the concrete characteristic resistance, and the group of local variables, represented here by the areas of the longitudinal steel reinforcement in the cross-sections of the columns. Consequently, a global optimization problem is defined for the global variables, at the global level, and local independent optimization sub- problems are defined for the local design variables, at the local levels, following each iteration at the global level. The objective function of the optimization problem is the total cost of the columns of the building. The buildings are modeled as three dimensional frames and geometric nonlinear behavior is considered in the structural analysis. The assumption of rigid diaphragm is adopted for the structural behavior of the slabs and the torsional stiffness of elements is neglected. Dead, live and wind loads are applied to the model. Constraints related to ultimate and serviceability limit states, as well as lateral constraints, are imposed to the design variables. The limit states are defined according to the Brazilian Code for reinforced concrete structures NBR-6118 (2003). The solution of the optimization problem is obtained using Mathematical Programming techniques.

This work describes a procedure for a soft sensor design to predict the top composition of a methanol-water distillation column. Soft sensor is a mathematical model that is used to estimate variables of interest from secondary variables easy to measure. This technique comes from an operational difficulty or high cost obtaining the desired variable. The approach to build a soft sensor was an artificial intelligence modeling, a black-box type, using a hybrid neuro-fuzzy technique. The data acquisition to train and validate the soft sensor comes from a mathematical model validated from pilot plat data. One of the limitations of neuro-fuzzy system is that it works with a limited number of inputs, depending on the combinatorial explosion of fuzzy rules. To minimize these effects and to reduce the number of rules in the training data sets of virtual analyzer, a data clustering technique called substractive clustering was used. To obtain a better performance of soft sensor for the dynamic process, distillation column, a regression of lone sampling time in selected variables was used, changing the number of entries from 9 to 18 variables, nine variables at actual sampling time and nine variables at previous sampling time. The distillation column is a good process for the present study because composition measurements are the main objective of this process and are difficult to obtain. The computational strategy for a soft sensor design produced good results in estimating the top composition of the methanol-water distillation column. / Este trabalho descreve um procedimento para o desenvolvimento de um analisador virtual, para predição da composição de topo de uma coluna destilação metanol-água em uma planta piloto. Analisador virtual é um modelo matemático que é usado para estimar variáveis de interesse a partir de variáveis secundárias de fácil medição. Esta tecnologia surge de uma real dificuldade operacional ou do alto custo de obtenção da variável desejada. O modelo utilizado nesta abordagem de construção do analisador virtual utiliza técnicas de sistemas inteligentes, tipo caixa preta, através da técnica híbrida neuro-fuzzy. A aquisição dos dados para treinar e validar o analisador virtual foi feita através de um modelo matemático validado a partir de dados experimentais da planta piloto. Uma das limitações do sistema neuro-fuzzy é que ele trabalha com um número limitado de entradas, dependendo da explosão combinatória das regras fuzzy. Para minimizar estes efeitos e conseguir reduzir o número de regras nos conjuntos de treinamento da rede neuro-fuzzy, foi utilizada a técnica de agrupamento de dados, denominada agrupamento substrativo. Com a intenção de se obter um melhor desempenho do analisador virtual no processo dinâmico, que é a coluna de destilação, foi empregada uma regressão de um tempo de amostragem nas variáveis de entrada selecionadas, alterando o número de entradas de 9 para 18, sendo 9 variáveis no tempo de amostragem atual e 9 variáveis em um tempo de amostragem anterior. O processo de destilação mostrou-se adequado para o presente estudo, pois as medições de composições são de difíceis obtenções. A estratégia computacional para um projeto de analisador virtual produziu bons resultados, de forma a estimar a composição do topo da coluna de destilação binária metanol-água.

Submitted by Roberta Cristina Possamai (possamai.beta@gmail.com) on 2017-02-17T18:14:37Z No. of bitstreams: 1 Dissertação Roberta Possamai_versão final (fev2017).pdf: 1492795 bytes, checksum: 82c01178c5b43c7624c12c1c6c19b43b (MD5) / Approved for entry into archive by Fabiana da Silva Segura (fabiana.segura@fgv.br) on 2017-02-17T18:29:06Z (GMT) No. of bitstreams: 1 Dissertação Roberta Possamai_versão final (fev2017).pdf: 1492795 bytes, checksum: 82c01178c5b43c7624c12c1c6c19b43b (MD5) / Made available in DSpace on 2017-02-20T12:24:03Z (GMT). No. of bitstreams: 1 Dissertação Roberta Possamai_versão final (fev2017).pdf: 1492795 bytes, checksum: 82c01178c5b43c7624c12c1c6c19b43b (MD5) Previous issue date: 2017-02-02 / Under what technical and market conditions does an integrated croplivestock system (iLP) become economically viable in the Brazilian Savanna? Despite the productive and environmental advantages of the iLP systems and the conditions that make them technically feasible, the evaluation of their economic viability is fundamental for the implementation, consolidation and expansion of this modality of productive arrangement. The objective of this study is to evaluate under what technical and market conditions an iLP system becomes economically viable or ceases to be. In order to carry out such analysis, the analysis started with a representative (hypothetical) farm located in the Brazilian Savanna biome. The assessment of economic viability was based on the analysis of the Discounted Cash Flow of this farm and considered the 2016 economic and financial indicators as the base scenario. Based on that scenario, the study also evaluated how the economic viability of an iLP project changes from shocks on key variables. Among the results, it is noteworthy that, although the iLP system has proved to be economically profitable in most of the simulated scenarios, cyclical changes decisively affect the economic viability of the project. / Sob quais condições técnicas e de mercado um sistema de integração lavoura-pecuária (iLP) se torna economicamente viável no Cerrado? Em que pese as vantagens produtivas e ambientais dos sistemas iLP e as condições que os tornam tecnicamente factíveis, a avaliação de sua viabilidade econômica é fundamental para a implementação, consolidação e expansão dessa modalidade de arranjo produtivo. O objetivo dessa dissertação é avaliar sob quais condições técnicas e de mercado um sistema iLP se torna ou deixa de ser economicamente viável. Para realizar tal análise, partiu-se de uma propriedade rural representativa (hipotética) localizada no bioma Cerrado. A avaliação da viabilidade econômica se deu por meio da análise do Fluxo de Caixa Descontado dessa propriedade, considerando como cenário referencial os indicadores econômico-financeiros de 2016 (dados secundários). A partir desse cenário base e dando choques na principais variáveis do sistema, foram simulados cenários alternativos de forma a identificar sob quais condições o projeto se torna ou deixa de ser economicamente viável. Entre os resultados encontrados, destaca-se que, embora o sistema iLP tenha se mostrado economicamente rentável na maioria dos cenários simulados, alterações conjunturais afetam de forma decisiva a viabilidade econômica do projeto.

Un certain nombre d’écoulements géophysiques, tels que les écoulements de glace ou de lave magmatique, impliquent le mouvement gravitaire à faible nombre de Reynolds d’un fluide viscoplastique à surface libre sur un socle rocheux. Leur modélisation fait apparaître des lois de comportement rhéologique et des descriptions de leurs intéractions avec le socle rocheux qui reposent sur des paramétrisations empiriques. Par ailleurs, l’observation systématique de ce type d’écoulements avec une grande précision est rarement possible ; les données associées à l’observation de ces écoulements, principalement des données de surface (télédétections), peuvent être peu denses, manquantes ou incertaines. Elles sont aussi le plus souvent indirectes : des paramètres inconnus comme le glissement basal ou la rhéologie sont difficilement mesurables in situ.Ce travail de thèse s’attache à la modélisation directe et inverse de ces écoulements géophysiques, particulièrement les écoulements de glace, par des méthodes variationnelles à travers la résolution du problème de Stokes pour les fluides en loi de puissance.La méthode de résolution du problème direct (Stokes non-linéaire) repose sur le principe du minimum de dissipation qui mène à un problème variationnel de type point-selle à quatre champs pour lequel on montre l’existence de solutions. La condition d’incompressibilité et la loi de comportement représentent alors des contraintes associées au problème de minimisation. La recherche des points critiques du lagrangien correspondant est réalisée à l’aide d’un algorithme de type lagrangien augmenté, discrétisé par éléments finis triangles à trois champs. Cet algorithme conduit à un important gain tant en temps de calcul qu’en utilisation mémoire par rapport aux algorithmes classiques.On s’intéresse ensuite à la modélisation numérique inverse de ces fluides à l’aide du modèle adjoint et des deux principaux outils associés : l’analyse de sensibilité et l’assimilation de données. On étudie tout d’abord la modélisation rhéologique de ces fluides à travers les deux paramètres principaux de la loi de comportement : la consistance du fluide et l’exposant rhéologique. Des analyses de sensibilité sur ces paramètres définis localement, permettent de quantifier leurs poids relatifs au sein du modèle d’écoulement, en termes de vitesses de surface. L’identification de ces grandeurs est également réalisée. L’ensemble des résultats est résumé comme une méthodologie vers une “rhéométrie virtuelle” pouvant représenter une aide solide à la mesure rhéologique.Le glissement basal, paramètre majeur dans la dynamique de la glace, est investigué selon la même approche. Les analyses de sensibilité mettent en avant une capacité à voir à travers le caractère “filtré” et non-local de la transmission de la variabilité basale vers la surface, ouvrant des perspectives vers l’utilisation des sensibilités pour la définition de lieux d’intérêt pour l’observation et la mesure. Ce glissement basal, modélisation empirique d’un processus complexe et multiéchelle, est ensuite utilisé pour la comparaison avec une méthode inverse approximative courante en glaciologie (méthode négligeant la dépendance de la viscosité à la vitesse, i.e. la non-linéarité). Le modèle adjoint, obtenu par différentiation automatique et évalué par accumulation retour, permet de définir cette approximation comme un cas limite de la méthode inverse complète. Ce formalisme mène à une généralisation du processus d’évaluation numérique de l’état adjoint, ajustable en précision et en temps de calcul en fonction de la qualité des données et du niveau de détail souhaité dans la reconstruction.L’ensemble de ces travaux est associé au développement du logiciel DassFlow-Ice de simulation directe et inverse de fluides viscoplastiques à surface libre. Ce logiciel prospectif bidimensionnel, diffusé dans la communauté glaciologique, a donné lieu au développement d’une version tridimensionnelle. / Several geophysical flows, such as ice flows or lava flows, are described by a gravity-driven low Reynolds number movement of a free surface viscoplastic fluid over a bedrock. Their modeling involves constitutive laws, typically describing their rheological behavior or interactions with their bedrock, that lean on empirical parameterizations. Otherwise, the thorough observation of this type of flows is rarely possible; data associated to the observation of these flows, mainly remote-sensed surface data, can be sparse, missing or uncertain. They are also generally indirect : unknown parameters such as the basal slipperiness or the rheology are difficult to measure on the field.This PhD work focuses on the direct and inverse modeling of these geophysical flows described by the power-law Stokes model, specifically dedicated to ice flows, using variational methods.The solution of the direct problem (Stokes non-linear) is based on the principle of minimal dissipation that leads to a variational four-field saddle-point problem for which we ensure the existence of a solution. In this context, the incompressibility condition and the constitutive rheological law represent constraints associated to the minimization problem. The critical points of the corresponding Lagrangian are determined using an augmented Lagrangian type algorithm discretized using three- field finite elements. This algorithm provides an important time and memory saving compared to classical algorithms.We then focus on the inverse numerical modeling of these fluids using the adjoint model through two main associated tools : sensitivity analysis and data assimilation. We first study the rheological modeling through the two principal input parameters (fluid consistency and rheological exponent). Sensitivity analyses with respect to these locally defined parameters allow to quantify their relative weights within the flow model, in terms of surface velocities. Identification of these parameters is also performed. The results are synthetized as a methodology towards “virtual rheometry” that could help and support rheological measurements.The basal slipperiness, major parameter in ice dynamics, is investigated using the same approach. Sensitivity analyses demonstrate an ability to see beyond the ”filtered” and non-local transmission of the basal variability to the surface. Consequently these sensitivities can be used to help defining areas of interest for observation and measurement. This basal slipperiness, empirical modeling of a multiscale complex process, is then used to carry on a comparison with a so called “self-adjoint” method, common in glaciology (neglecting the dependency of the viscosity on the velocity, i.e. the non-linearity). The adjoint model, obtained by automatic differentiation and evaluated by reverse accumulation, leads to define this approximation as a limit case of the complete inverse method. This formalism allows to generalize the process of the numerical evaluation of the adjoint state into an incomplete adjoint method, adjustable in time and accuracy depending on the quality of the data and the level of detail required in the identification.All this work is associated to the development of DassFlow-Ice software dedicated to the direct and inverse numerical simulation of free-surface viscoplastic fluids. This bidimensional prospective software, distributed within the glaciological com- munity, serves as a model for the current development of the tridimensional version.

This thesis deals with the issue of investment decisions, which is important for every business. The aim of this thesis was to evaluate the effectiveness of selected investment project.First, we conducted a financial analysis to assess the current status of the company. Then we have identified the revenue and expenditure of the project. We also have assessed the effectiveness of investments in several variants. At the conclusion of the project was assessed risk.

L'utilisation de pesticides sur les surfaces agricoles conduit à une contamination généralisée des eaux de surface et de subsurface en France. Dans l'attente d'une évolution profonde des pratiques agricoles et d'une baisse durable de l'utilisation des pesticides, il est intéressant de chercher à limiter des transferts des zones agricoles aux zones aquatiques. Pour mieux agir sur les voies de transfert, il est nécessaire d'approfondir les connaissances des processus en jeu et de leurs interactions éventuelles et de tirer au mieux partie des observations du terrain.L'objectif de cette thèse est l'intégration de processus de transferts réactif dans le modèle hydrologique à base physique CATHY (CATchment HYdrology), capable de simuler en 3 dimensions les écoulements de l'eau de façon couplée surface-subsurface et le transport advectif dans des situations variablement saturées. En subsurface, les processus d'adsorption linéaire et de dégradation du premier ordre sont implémentés. Un module de mélange des solutés entre la lame ruisselante et la première couche de sol est ajouté, qui permet de simuler la remobilisation des solutés de la subsurface dans le ruissellement. Le couplage surface-subsurface des écoulement est très efficace dans ce modèle, et le couplage du transport de soluté adoptant la même stratégie a été amélioré pour mieux respecter la conservation de la masse.Le modèle est en premier lieu testé sur des données issues d'expérimentations de transfert de subsurface sur une maquette de laboratoire à petite échelle (2 m de long, o.5 m de large, 1 m de profondeur). Les résultats sont confrontés aux chroniques de flux massiques observées et une analyse de sensibilité de type Morris est menée. Le modèle est capable de reproduire de façon satisfaisante les observations, et très satisfaisante après une légère calibration. Les conductivités à saturation horizontale et verticale, la porosité et le paramètre $n$ de la courbe de rétention influencent de façon non négligeable les résultats hydrodynamiques et de transfert de soluté. Dans un second temps, le modèle est évalué sur les données issus d'un versant viticole réel (0.6 ha) dans un contexte orageux avec de fortes interactions surface-subsurface. Une analyse de sensibilité globale est menée, et met en valeur les mêmes paramètres que la méthode de Morris. Les interactions entre les paramètres influencent fortement la variabilité des sorties hydrodynamiques et de transfert. La conservation de la masse est très correctement assurée malgré la complexité de la simulation.Le modèle auquel on aboutit correspond bien aux objectifs de départ, sa validation est solide, même si elle n'est rigoureusement valable que dans les contextes précis où elle a été réalisée. On a montré que le modèle était robuste et capable de reproduire des données observées. D'autres processus manquent encore pour représenter toutes les voies de transfert à l'échelle du versant, notamment la représentation du transfert préférentiel en subsurface et du transport sédimentaire en surface. / Pesticide use on agricultural surfaces leads to a broad surface and subsurface water contamination in France. Awaiting a deep agricultural practices evolution and a sustained fall of the pesticide use, it is of interest to limit transfers form agricultural fields to rivers. In order to constrain those transfers, a deepen knowledge of processes at stake and their potential interactions is necessary, as well as taking full advantages of fields observations.The aim of this PhD is the reactive transfer processes integration in the Hydrological physically-based model CATHY (CATchment HYdrology) which simulates surface-subsurface coupled water flow and advectiv solute transport in three dimensions and in variably saturated situations. Linear adsorption and first order decay are implemented in subsurface. A mixing modules is added, and evens the concentration between surface runoff and subsurface first layer. This module simulates the solute mobilisation from soil to surface runoff. The water flow surface-subsurface coupling procedure is very accurate in CATHY, and the transport coupling procedure is improve in order to respect the mass conservation.The model is first evaluated on subsurface transfer laboratory experimentation data at a small scale (2 m long, o.5 m wide, 1 m deep). Results are compared to mass flux evolution in time and a Morris sensitivity analysis is conducted. The model is able to acceptably reproduce observation, and properly after a slight calibration. Horizontal and vertical saturated conductivities, porosity and the $n$ parameter of retention curve significantly influence hydrodynamics and solute transport. As a second step, the model is evaluated on data from a field wine hillslope on an intense rain event, therefore in a context with a lot of surface-subsurface interactions. A global sensitivity analysis is conducted and highlights same parameters as the Morris method. Interactions between parameters highly influence the variability of hydrodynamic and solute transfer outputs. Mass conservation is accurate despite the complexity of the context.The resulting model meets the objectives, its evaluation is strong even if its theoretically only valid in the precise context in which the evaluations where conducted. The model is robust and able to reproduce observed data. Some complementary processes are still missing in the model to properly represent transfer ways at the hillslope scale, such as subsurface preferential transfers and surface sedimentary transport.