The effect of in-situ or redistributed stress on solute transport in fractured rocks is one of the major concerns for many subsurface engineering problems. However, it remains poorly understood due to the difficulties in experiments and numerical modeling. The main aim of this thesis is to systematically investigate the influences of stress on solute transport in fractured rocks, at scales of single fractures and fracture networks, respectively. For a single fracture embedded in a porous rock matrix, a closed-form solution was derived for modeling the coupled stress-flow-transport processes without considering damage on the fracture surfaces. Afterwards, a retardation coefficient model was developed to consider the influences of damage of the fracture surfaces during shear processes on the solute sorption. Integrated with particle mechanics models, a numerical procedure was proposed to investigate the effects of gouge generation and microcrack development in the damaged zones of fracture on the solute retardation in single fractures. The results show that fracture aperture changes have a significant influence on the solute concentration distribution and residence time. Under compression, the decreasing matrix porosity can slightly increase the solute concentration. The shear process can increase the solute retardation coefficient by offering more sorption surfaces in the fracture due to gouge generation, microcracking and gouge crushing. To study the stress effects on solute transport in fracture systems, a hybrid approach combing the discrete element method for stress-flow simulations and a particle tracking algorithm for solute transport was developed for two-dimensional irregular discrete fracture network models. Advection, hydrodynamic dispersion and matrix diffusion in single fractures were considered. The particle migration paths were tracked first by following the flowing fluid (advection), and then the hydrodynamic dispersion and matrix diffusion were considered using statistic methods. The numerical results show an important impact of stress on the solute transport, by changing the solute residence time, distribution and travel paths. The equivalent dispersion coefficient is scale dependent in an asymptotic or exponential form without stress applied or under isotropic compression conditions. Matrix diffusion plays a dominant role in solute transport when the hydraulic gradient is small. Outstanding issues and main scientific achievements are also discussed. / QC 20111011

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-08-25T12:32:10Z No. of bitstreams: 1 Hugo Henrique Costa do Nascimento.pdf: 1093774 bytes, checksum: eb85afbd1a40d83514ec8248cffd373e (MD5) / Made available in DSpace on 2016-08-25T12:32:11Z (GMT). No. of bitstreams: 1 Hugo Henrique Costa do Nascimento.pdf: 1093774 bytes, checksum: eb85afbd1a40d83514ec8248cffd373e (MD5) Previous issue date: 2009-02-13 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The objective of the present work was to analyze the growth, water relations, gas exchange and quantification of organic solutes of jatobá (Hymenaea courbaril L.) seedlings under water deficit. The experiment was conducted in a greenhouse conditions at the Laboratory of Plant Physiology of the Universidade Federal Rural de Pernambuco, between August 2007 and January 2008, with trial period of 105 days. The plants were cultivated in vases with 8 kg of soil from where the seeds were collected. Randomized blocks were used as experimental design, with four water treatments (100%, 75%, 50% and 25% of the field capacity) and six replicates. Plant height, number of leaves and stem diameter were evaluated weekly. At the end of the experimental period, leaf area, leaf area ratio, specific leaf area, leaves, stem, root and total dry matter production and the biomass allocation to the several organs were determined. The leaf water potential was evaluated in three times (35, 70 and 105 days after differentiation) in two hours of evaluation (antemanhã and midday). The relative water content was measured only at the end of the experiment, using the leaves used in the analysis of midday leaf water potential. Temperature and relative humidity measures were taken daily inside the greenhouse for the calculation of the water deficit pressure. Transpiration and diffusive resistance were evaluated fortnightly. At the end of the experiment were measured the concentrations of soluble carbohydrates, soluble proteins and free proline. The water deficit affected the plant growth reducing plant height, stem diameter and dry matter production of all organs when cultivated in water levels with less than 50% of the field capacity. The number of leaves decreased in all stress levels when compared to 100% of field capacity. However, the pattern of biomass allocation, root:shoot ratio, leaf area ratio and specific leaf area were not affected by the stress. The applied water stress influenced the water relations of plants, restricting significantly the leaf water potential and relative water content, which are highly correlated. We observed significant increases in levels of organic solutes, according to the severity of the treatments, and proline, the organic solute that showed greater sensitivity to water deficit. The number of leaves was the variable more sensible to stress. Jatobá seedlings do not paralyze their growth when cultivated in soil with low water availability in theirinitial development stage. However its growth is severely affected by water levels less than 50% of water retention capacity in the soil. Overall, 35 days of exposure to 50% of the field capacity, do not affect the water potential of seedlings of jatobá, suggesting that the species is able to tolerate moderate stress, during the period. Finally the variables were good physiological indicators because easily indicated differences between the treatments. / O objetivo do presente trabalho foi analisar o crescimento, relações hídricas, trocas gasosas e a quantificação dos solutos orgânicos de mudas de jatobá (Hymenaea courbaril L.) sob déficit hídrico. O experimento foi desenvolvido em casa de vegetação do Laboratório de Fisiologia Vegetal da Universidade Federal Rural de Pernambuco, entre agosto de 2007 a janeiro de 2008, com período experimental de 105 dias. As mudas foram cultivadas em vasos contendo 8 kg de solo oriundo do local de coleta das sementes. Foram utilizados blocos casualizados como delineamento experimental, com quatro tratamentos hídricos (100%, 75%, 50% e 25% da capacidade de pote) e seis repetições. Semanalmente foram avaliados a altura das plantas, o número de folhas e o diâmetro do caule. Ao final do período experimental, foram determinadas a área foliar, a razão de área foliar e a área foliar específica, a produção de matéria seca das folhas, caule, raízes e total e a alocação de biomassa para as folhas, caule e raízes. O potencial hídrico foliar foi avaliado em três épocas (35, 70 e 105 dias após a diferenciação dos tratamentos) em dois horários de avaliação (antemanhã e meio-dia). O teor relativo de água foi avaliado apenas ao termino do experimento, utilizando-se as folhas utilizadas nas análises do potencial hídrico de meio-dia. Diariamente foram tomadas medidas da temperatura e umidade relativa do ar no interior da casa de vegetação para o calculo do déficit de pressão de vapor d água. Também foram avaliadas, quinzenalmente, a transpiração e a resistência difusiva. Ao final do experimento foram quantificadas as concentrações de carboidratos solúveis, proteínas solúveis e prolina livre. O déficit hídrico afetou o crescimento das plantas quanto à altura, diâmetro do caule e produção de matéria seca para os diversos órgãos quando cultivadas em níveis a partir de 50% da CP. O número de folhas reduziu em todos os níveis de estresse, quando comparados com o tratamento 100% da CP. O padrão de alocação de biomassa, a relaçãoraiz/parte aérea, a razão de área foliar e a área foliar específica, no entanto, não foram afetados pelo estresse. O estresse hídrico aplicado atuou nas relações hídricas das plantas, restringindo significativamente o potencial hídrico e o teor relativo de água das folhas, e os mesmos, se apresentaram altamente correlacionados. Com o aumento do estresse hídrico observaram-se reduções significativas na transpiração e consequente aumento naresistência difusiva. Foram observados aumentos significativos nos teores de solutos orgânicos, de acordo com a severidade dos tratamentos, sendo a prolina o soluto orgânico que apresentou maior sensibilidade à deficiência hídrica. O número de folhas foi à variável mais sensível ao estresse. Mudas de jatobá não paralisam o seu crescimento quando cultivadas com baixa disponibilidade de água no solo na fase inicial do desenvolvimento. No entanto, seu crescimento é severamente afetado em níveis de água abaixo de 50% da capacidade de retenção de água no solo. De forma geral, as mudas de jatobá cultivadas a 50% da CP, não evidenciam redução no potencial hídrico após 35 dias de exposição ao estresse, sugerindo que a espécie é capaz de tolerar estresses moderados, durante o referido período. Por fim, as variáveis estudadas foram boas indicadoras fisiológicas, pois facilmente refletiram diferenças entre os tratamentos estudados e sugerem que mudas de jatobá (Hymenaea courbaril L.) toleram níveis moderados de seca.

A preocupação com o destino de produtos químicos e água, aplicados ao solo, tem motivado vários pesquisadores a desenvolverem e aplicarem modelos teóricos, objetivando descrever os processos físicos envolvidos no transporte desses produtos no perfil do solo. Nesse sentido, a presente pesquisa teve como objetivo a aplicação do modelo Hydrus-1D para simulação do movimento da água e dos íons nitrato e potássio, em condições de laboratório, utilizando-se para tal colunas segmentadas preenchidas com dois tipos de solo não-saturado (Latossolo Vermelho Amarelo e Nitossolo Vermelho), bem como avaliar o desempenho e sensibilidade do referido modelo. Para a obtenção dos parâmetros de transporte de cada soluto, foram elaboradas as curvas de distribuição de efluentes (Breakthrough Curves BTC). Os parâmetros de transporte obtidos e as condições de contorno de cada ensaio foram inseridos no modelo Hydrus- 1D para realização das simulações. O desempenho do modelo foi avaliado com base nos parâmetros estatísticos: erro máximo, erro absoluto médio, raiz quadrada do erro médio normalizado, coeficiente de massa residual, coeficiente de determinação, eficiência e índice de concordância de Willmott. A sensibilidade do modelo foi avaliada conforme o método proposto por McCuen e Snyder (1986) e a análise foi aplicada aos parâmetros: fluxo de entrada, condutividade hidráulica do solo saturado, teor de água na saturação, alfa e n (parâmetros de ajuste da curva de retenção), coeficiente de distribuição e dispersividade. Os resultados experimentais mostraram que o deslocamento do íon nitrato acompanhou a frente de molhamento e em relação ao potássio, observou-se uma maior retenção nas camadas superficiais da coluna de solo, para ambos os solos. Pôde-se concluir que o modelo Hydrus-1D foi eficiente para simulações de deslocamento de potássio e água para ambos os solos estudados e mediante a utilização do modelo de equilíbrio para o transporte de solutos no solo, o modelo Hydrus-1D não foi eficiente para simular o deslocamento de nitrato, para ambos os solos. Os procedimentos experimentais para estimativa de parâmetros de transporte, como as curvas de distribuição de efluentes, foram suficientes para descrever a movimentação de potássio no solo, gerando informações de entrada precisas para os modelos de simulação. Para a simulação do deslocamento do íon nitrato, concluiu-se que o modelo Hydrus-1D requer um processo experimental mais detalhado, sendo necessária a estimativa de um maior número de parâmetros de transporte. Em relação à análise de sensibilidade, ao simular os teores de potássio e água no solo, o modelo apresentou maior sensibilidade aos parâmetros teor de água na saturação e fluxo de entrada da solução. Tais parâmetros, portanto, precisam ser determinados com maior precisão. Houve baixa sensibilidade aos parâmetros condutividade hidráulica do solo saturado e dispersividade, para ambos os solos estudados. / The concern about the fate of chemical products and water, applied to the soil, has been motivating several researchers to develop and apply theoretical models, aiming to describe the physical processes involved in the transport of those products in soil profile. The present research had as objective the application of the model Hydrus- 1D for water and solute (nitrate and potassium) simulation profile, in laboratory conditions, using soil columns filled with two types of unsaturated soil (Oxisol (Haplustox) and Hapludox), as well to evaluate the acting and sensitivity of the model. The transport parameters were obtained for each solute by breakthrough curves (BTCs). The transport parameters obtained and the boundary conditions were inserted in the Hydrus-1D model to realize the simulations. The acting of the Hydrus-1D model was evaluated using the statistical indicators: maximum error, mean absolute error, normalized root mean-square error, coefficient of residual mass, determination coefficient, efficiency and Willmott concordance index. The model sensitivity was evaluated by the method proposed by McCuen and Snyder (1986) and applied to the parameters: input flow, soil saturated hydraulic conductivity, water content (saturation point), alpha and n (soil water retention curve parameters), distribution coefficient and dispersivity. The obtained results, experimentally, showed the nitrate displacement following the wetting front and, in relation to the potassium ion, a larger retention was observed at the superficial soil columns layers. Therefore, was possible to conclude that Hydrus-1D model was efficient for both water and potassium displacement simulations, for both studied soils and by the balance model for solute transport in soil, the Hydrus- 1D model was not efficient to simulate the nitrate displacement in both soils. The experimental procedures to estimate transport parameters, by the BTCs, were enough to describe the potassium movement in soil, generating input information necessary to the model simulation. To the simulation of the nitrate displacement, was possible to conclude that the model Hydrus-1D requests a more detailed experimental process, being necessary the estimate of a larger number of transport parameters. In relation to the sensitivity analysis of the Hydrus-1D model, when simulated the content of potassium and water at the soil columns, was observed that the model shows more sensitivity about to the parameters: water content (saturation point) and input flow. This parameters need to be estimated with more precision. There was a low sensitivity to the parameters soil saturated hydraulic conductivity and dispersivity for both studied soils.

Foi estudado, através de ensaio de tração, o Nb policristalino com teor de hidrogênio de 0 a 50 partes por milhão em peso (ppm-p) nas temperaturas de 223, 273 e 293 K. Os ensaios de tração a velocidades constantes foram realizados com taxas iniciais de deformaçao de 4,2 X 10-5 e 42 X 10-5 s-1 , e os parâmetros de ductilidade e resistência mecânica foram analisados em função da concentração de hidrogênio. Foram também obtidos o coeficiente de sensitividade a taxa de deformação (m) e o volume de ativação (V) através de ensaios de tração, alternando-se abruptamente a taxa de deformação entre os valores acima mencionados, em sucessivos pontos da curva tensão-deformação. Para o cálculo destes dois últimos parâmetros foi proposta uma análise detalhada, considerando-se os efeitos elásticos e o encruamento durante a deformação plástica uniforme. Todo o estudo foi acompanhado por análise fratográfica Que permitiu verificar três comportamentos de ruptura da liga Nb-H, dependendo do teor de hidrogênio e da temperatura. A 223K foi observado que há uma forte redução de ductilidade do Nb para teores de hidrogênio até 10 ppm-p, sendo que para este teor o seu comportamento foi totalmente frágil / Tensile testing at 223, 273 and 293 K was carried out on polycrystalline Nb dopped from 0 to 50 parts per million in weight (ppm-wt) of Hydrogen. The tensile testing at constant velocity was done at 4,2 X 10 -5 and 42 X 10-5 s-1 of initial strain rate, and the ductility and strength parameters was analysed as a function of the hydrogen content. It was also obtained the strain rate sensitivity (m) and the activation volume (V), from tensile testing, cycling between the two above specified strain rates, at several points of the stress-strain curve. For the calculation of this two last parameters it was proposed a detailed analysis, considering the elastic effect and the work hardening during the uniform plastic deformation. All these studies was followed by fratographic analysis that alowed the identification of three rupture behavior for the Nb-H alloy, depending of the temperature and the hydrogen content. At 223 K, it was observed that there is a strong embrittlement of Nb for hydrogen content up to 10 ppm-wt, and for this value the behavior was completely brittle

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-27T17:37:56Z No. of bitstreams: 1 stefanosleitegeorgopoulos.pdf: 4197342 bytes, checksum: 2974d92b3639af53c51f602c3cd7723f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-13T13:03:11Z (GMT) No. of bitstreams: 1 stefanosleitegeorgopoulos.pdf: 4197342 bytes, checksum: 2974d92b3639af53c51f602c3cd7723f (MD5) / Made available in DSpace on 2017-05-13T13:03:11Z (GMT). No. of bitstreams: 1 stefanosleitegeorgopoulos.pdf: 4197342 bytes, checksum: 2974d92b3639af53c51f602c3cd7723f (MD5) Previous issue date: 2014-08-25 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A investigação das soluções de ácido esquárico (H2SQ), diprótico, em dimetilsulfóxido, utilizando a espectroscopia Raman, com o auxílio do cálculo dos métodos numéricos, possibilitou identificar e determinar quantitativamente diversas espécies formadas em solução, distinguindo também as possíveis interações entre o solvente e o soluto e, ainda, a interação entre os solutos vizinhos. A identificação destas interações permitiu tanto a descoberta de espécies químicas na solução, como o H2SQ não-dissociado, formando complexo e não formando complexo, como a fração de H2SQ que se dissociou, formando o ânion monovalente hidrogeno-esquarato (HSQ-) e o ânion divalente esquarato (SQ2-). Também se fez a determinação do tipo de interação predominante que ocorre entre os H2SQ, explicando-se a razão de surgir a cor rosa nas soluções que contêm o H2SQ como soluto, através da interação π-π entre os anéis vizinhos. A formação de sistemas cristalinos através dos sais contendo os cátions tetraalquilamônio e os ânions originados dos oxocarbonos, tais como o íon SQ2-, o ânion divalente croconato e o íon HSQ-, fornece condições de investigar como a variação do volume do cátion influencia na forma da dissociação iônica sofrida pelo H2SQ. Ao compararmos os diferentes sais de tetraalquilamônio, podemos perceber a avidez do ânion divalente croconato, por moléculas de água, e a preferência dos ânions derivados do H2SQ e do próprio H2SQ por realizar ligações de hidrogênio entre si, em solução aquosa. Estes sistemas cristalinos mostram claramente a maior “maciez” da nuvem eletrônica dos íons originados a partir da dissociação iônica do H2SQ do que a daqueles originados no íon croconato. A formação exclusiva do íon SQ2-, ligado, por ponte de hidrogênio, a outros dois H2SQ, no esquarato de tetrabutilamônio, enquanto no sal de tetrapropilamônio há apenas dois íons HSQ-, ligados por pontes de hidrogênio entre si, mostram o quanto o volume do cátion influencia na quantidade de dissociação iônica sofrida pelo H2SQ. / Investigations of the diprotic squaric acid (H2SQ) solutions in dimethylsulfoxide using Raman spectroscopy supported by numerical method calculation, were able to identifying and measure the amounts of the several species present in solutions, taking into account the interactions between solvent and solute, as well as the neighbouring solutes. The identification of such interactions allowed the discover of the chemical species present in the solution, as for instance the complex and non-complex H2SQ associated species, and the dissociated H2SQ, as a fraction of the hydrogen squarate anion (HSQ-) and divalent anion squarate (SQ2-). In addition, the type of interaction between neighbors H2SQ has also been determined, justifying the reason of an emerging pink color for the H2SQ solutions, probably generated by π-π interaction between neighbor rings of H2SQ species. The synthesis of a crystaline system originated by tetraalkylammonium cations and oxocarbon anions, as a SQ2- ion, croconate divalent anion and HSQ- ion was able to investigate how the variation of the cationic volume can influence the type of ionic dissociation presented by the different H2SQ species. When comparing different tetraalkylammonium salts, it can be noticed a great affinity by water molecules from croconate divalent anion, and the preference of the anions derived from H2SQ to perform hydrogen bonds between them, in aqueous solution. This crystalline system shows more “softly” electronic clouds of the ions originated from ionic dissociation of the H2SQ than croconate ion. Exclusive formation of the SQ2- ion, bonded by htdrogen bonds, for two H2SQ species, in the tetrabutylammonium squarate salts, while in the tetrapropylammonium salts have only two HSQ- ions, bonded by hydrogen bonds between them, has also showed how the cation volume can be an important influence for the ionic dissociation quantities suffered by H2SQ.

La plupart des données existantes de diffusion d'eau et de solutés sont obtenues pour des roches argileuses extrêmement complexes ou des échantillons en apparence plus simples préparés à base d'argiles gonflantes sodiques de type smectite. Ces dernières pouvant présenter des organisations très variables et encore mal comprises (phase gel-floc-suspension stable) en conditions saturées, il reste très difficile de contraindre les modèles à double milieu (eau porale ou interfoliaire) parfois avancés pour interpréter des expériences de diffusion. Un système modèle d'argiles gonflantes reflétant réellement un double milieu a pu être obtenu à partir de trois fractions granulométriques d'une vermiculite-Na. Celles-ci ne présentent pas de phase gel en conditions saturées mais des particules bien définies dont la morphologie et l'organisation ont pu être caractérisées. Un dispositif de diffusion a été développé afin d'étudier la diffusion de HDO et Br- pour ces différentes fractions en fonction de la porosité. L'avantage majeur de ce dispositif est de pouvoir préparer des échantillons par sédimentation analysables en tomographie de rayons-X afin de valider leur homogénéité organisationnelle ; hypothèse considérée dans les modélisations. Les résultats obtenus démontrent que cette nouvelle voie de préparation conduit à des échantillons plus homogènes par rapport aux méthodes classiques. Les premières perspectives quant à l'utilisation de ces doubles milieux modèles se dégagent à travers les premiers résultats de diffusion obtenus puisque leurs caractéristiques géométriques parfaitement contrôlées peuvent permettre de pondérer l'impact des différents processus de transport potentiels / Most of existing data on diffusion of water and solutes were obtained either on extremely complex clayey rocks or on seemingly more simple samples prepared from sodium-saturated swelling clay minerals, namely smectites. Because these latter can exhibit in water-saturated conditions various organizations not yet fully understood (gel phase-floc-stable suspension), it is still difficult to constrain dual-porosity media modeling (pore or interlayer water) sometimes considered for interpreting results from diffusion experiments. A model system for swelling clay minerals, mimicking a true dual-porosity medium, was obtained by using three size fractions of a Na-vermiculite. These fractions do not exhibit gel-like behavior in water-saturated conditions but rather well defined particles, whose morphology and organization have been characterized. An experimental set-up was designed for the investigation of HDO and Br- diffusion in these size-fractions as a function of porosity. The main advantage of this set up is that it allows assessing for the organizational homogeneity of a sample prepared by sedimentation process through X-ray tomography measurements, an assumption considered for diffusion modeling. The obtained results showed that this new method for sample preparation leads to more homogeneous samples as compared to classical procedures. The first perspectives concerning the use of these dual-porosity model systems are drawn from the first diffusion results obtained, as the well-controlled geometrical characteristics of these model systems successfully help in balancing the contribution of the different potential transport processes.

Solute carriers (SLCs) are membrane-bound transporter proteins, important for nutrient, ion, drug and metabolite transport across membranes. A quarter of the human genome codes for membrane-bound proteins, and SLCs make up the largest group of transporter proteins. Due to their ability to transport a large repertoire of substances across, not just the plasma membrane, but also the membrane of internal organelles, they hold a key position in maintaining homeostasis affecting metabolic pathways. Unfortunately, some of the more than 400 identified SLCs are still not fully characterized, even though a quarter of these are associated with human disease. In addition, there are about 30 membrane-bound proteins with strong resemblance to SLCs, of which very little is known. The aim of this thesis is to characterize some of these putative SLCs, focusing on their localization and function in the central nervous system. Since many of the known SLCs play a vital part in metabolism and related pathways, the response to different nutritional conditions has been used as a key method. MFSD14A and MFSD14B, characterized in Paper I, are putative SLCs belonging to the Major Facilitator Superfamily (MFS) and found to be neuronal, differentially expressed in the mouse central nervous system and transiently upregulated in mouse embryonic cortex cultures due to amino acid deprivation. They were also altered in areas of the mouse brain after starvation as well as after high fat diet. In Paper II, the effect on gene regulation due to complete amino acid starvation was monitored in a mouse hypothalamic cell line and 47 different genes belonging to SLCs, or putative SLCs, were found to be affected. Of these, 15 genes belonged to already known amino acid transporters, whereas 32 were putative SLCs with no known function or SLCs not known to react to amino acids. The three SV2 proteins, SV2A, SV2B and SV2C, were studied in Paper III using human neuroblastoma cell lines. The high metabolic state of cancers often result in an upregulation and alteration of transporter proteins, and alterations of the SV2 proteins were found following different treatments performed in this study. Paper IV focused on putative SLCs of MFS type and their role in glucose metabolism. Mouse embryonic cortex cultures were subjected to glucose starvation and the gene expression of 19 putative transporters were analyzed. All but four of the putative transporters were affected either at 3h or 12h of glucose deprivation. In conclusion, several SLCs and putative SLCs studied in this thesis are strongly affected by alteration in metabolism, either due to amino acids or glucose or both. This makes the putative SLCs dynamic membrane-bound proteins, possibly transporters, highly affected by nutritional status and most likely regulated to maintain homeostasis.

Dans cette thèse, nous avons étudié expérimentalement, numériquement et théoriquement la sédimentation d’un soluté en cellule de Hele-Shaw, modèle analogue de milieu poreux, avec un écoulement zonal horizontal. Une cellule, alimentée par deux grands réservoirs assurant un écoulement zonal uniforme, a été réalisée au laboratoire. La vitesse a été mesurée par PIV. L’injection d’une solution saline dans cet écoulement permet de visualiser la propagation du panache de pollution, et de mesurer le champ de concentration par LIF. Trois configurations typiques ont été observées : panache sans digitation (« stable »), avec une seule digitation (« faiblement instable »), et avec de nombreuses digitations (« fortement instable »). L’influence du contraste de densité, de la vitesse zonale, et du débit d’injection sur la stabilité du panache a été analysée. Ces résultats ont été comparés à des simulations numériques sous COMSOL Multiphysics®. Les champs de concentration simulés sont en accord quantitatif avec les champs expérimentaux. Ces simulations ont de plus permis d’étudier l’influence de l’anisotropie du tenseur de dispersion sur la stabilité du panache. Une étude théorique linéaire, effectuée à partir d’un écoulement de base unidirectionnel et quasi-stationnaire, est venue compléter ces résultats. Elle montre que le panache est toujours convectivement instable pour les valeurs des paramètres considérées, et permet de retrouver et de quantifier les principaux résultats mis en évidence lors des études expérimentale et numérique, comme l’effet stabilisant de la dispersivité longitudinale ou l’effet déstabilisant du contraste de densité / This thesis is an experimental and numerical investigation of solute transport and sedimentation in a Hele-Shaw cell with zonal flow. A vertical cell joining two large tanks has been built to provide a uniform horizontal flow, the velocity of which has been measured by using PIV. The concentration field of a solute injected in this flow has been measured by using LIF. Three typical plume configurations have been observed: without digitations (“stable”), with a single digitation (“weakly unstable”), and with various digitations appearing at the lower interface (“unstable plume”). The influence of density contrast, zonal flow and solute flow rate on the appearance of the various configurations has been investigated. These results have been compared to numerical simulations using the COMSOL Multiphysics® software. The numerical concentration fields are in qualitative agreement with the experimental ones. In addition, these simulations allowed us to investigate the effect of the anisotropy of the dispersion tensor on the occurrence of unstable configurations. A linear stability analysis based on a uniform parallel flow superposed to a quasi-steady horizontal layer of solute has been performed. It shows that the plume is convectively unstable for the parameters considered here, and confirms the various behaviors observed in both the experimental and the numerical analyses, like the stabilizing effect of the longitudinal dispersivity or the destabilizing effect of the solute concentration

Un dispositif en sol nu comprenant trois parcelles (90 m²) et six cases lysimétriques (4 m²) instrumentées a permis d’étudier l’influence d’apports répétés d’une boue de station d’épuration (BOUE) et de la même boue compostée avec des déchets verts (DVB) sur (i) les modifications des propriétés physico-chimiques et hydriques du sol ; (ii) le transport des ions bromures ; (iii) la dynamique de minéralisation du carbone et de l’azote organiques dans le sol. Finalement, le calage des paramètres hydrodynamiques et de décomposition de la matière organique dans le sol, propres à chaque horizon des profils de sols instrumentés, a permis une description satisfaisante de la dynamique hydrique et du transport des ions bromures et nitrates observés expérimentalement. Ces résultats aideront à l’adaptation de scénarios agronomiques sur le long terme pour répondre plus efficacement aux problématiques liées aux nouvelles exigences de recyclage des déchets et de protection de l’environnement. / An instrumented experimental bare soil site including three plots (90 m²) and six lysimeters (4 m²) has enabled to study the influence of repeated sewage sludge (SS) applications, as well as the same sewage sludge composted with green waste (SGW), on (i) the soil physicochemical and hydric properties ; (ii) the transport of bromide ions ; (iii) the organic carbon and nitrogen mineralization dynamics in soil. Finally, fitting the governing hydraulic parameters and the organic matter decomposition parameters in each soil horizon allowed a satisfying description of the experimentally observed water and bromide and nitrate ions transport in soil. These results will help conceive long-term agronomical scenarios aimed at providing more efficient answers to the new requirements of environmental protection and waste recycling policies.

Die Modellierung von komplexen Systemen, wie dem Untergrund, ist ein Hilfsmittel zur Beschreibung der in der Realität ablaufenden Prozesse. Die Durchführung von Experimenten an einem Modell, um qualitative Aussagen über ein reales System zu erhalten, wird als Simulation bezeichnet. Dabei können vielfältige Modelle, wie z.B. physikalische und mathematische, zum Einsatz kommen. Die ungesättigte Bodenzone (vadose Zone) bezeichnet den Bereich zwischen der Landoberfläche und dem Grundwasserspiegel, innerhalb dessen der Wassergehalt geringer als bei Vollsättigung, und der Druck geringer als der Atmosphärendruck ist. Dieser Bodenbereich hat für die Landwirtschaft, Geobiologie, aerobe Abbauprozesse und Grundwasserneubildung eine große Bedeutung. Für die Nachbildung von Strömungs- und Stofftransportprozessen der ungesättigten Bodenzone existieren numerische Simulationsprogramme. Ziel der vorliegenden Arbeit ist eine umfangreiche Validierung des Programms PCSiWaPro® (entwickelt an der TU-Dresden, Institut für Abfallwirtschaft und Altlasten) für unterschiedliche Anwendungsfälle. Ein weiteres Ziel der Arbeit besteht in der Untersuchung der Anwendbarkeit des aktuellen Stands des Simulationsprogramms PCSiWaPro® auf unterschiedliche Praxisfälle bei Kombination der ungesättigten Bodenzone mit technischen Anlagen. Vier Anwendungsfälle mit unterschiedlichen Zielen wurden dafür im Rahmen dieser Arbeit untersucht: die Simulation von dezentraler Abwasserversickerung (Kleinkläranlage - KKA) anhand entsprechender Säulen- und Feldversuche, die Berechnung der Grundwasserneubildung am Beispiel von Lysimetern, der Wasserhaushalt von Erddämmen und die Modellierung von Deponieabdeckungssystemen. Die Anwendungsfälle unterscheiden sich durch den Zweck der Simulation, die Geometrie, die Größe, die festgelegten Anfangs- und Randbedingungen, die Simulationszeit, die Materialien, das Koordinatensystem sowie die Ein- und Ausgabewerte. Die Simulationsergebnisse konnten eindeutig zeigen, dass das Programm PCSiWaPro® für alle im Rahmen der vorliegenden Arbeit untersuchten Fälle, mit unterschiedlichen Strömungsregimen, Stofftransport-Parametern, Randbedingungen, Koordinatensystemen sowie Raum- und Zeitdiskretisierungen anwendbar ist. Die Simulationsergebnisse der Säulenversuche am Beispiel dezentraler Abwasserversickerung zeigten eine sehr gute Übereinstimmung zwischen gemessenen und mittels PCSiWa-Pro® berechneten Werten des Wasser- und Stoffhaushaltes (Druckhöhe, Abfluss und Stoff-konzentration) der untersuchten Bodentypen B3 (schwachschluffiger Sand), B4 (Grobsand) und B5 (mittelschluffiger Sand). Die Wurzel des mittleren quadratischen Fehlers (RMSE) betrug für die Berechnung der Druckhöhe 1,84 cm bei B5, 3,61 cm bei B3 und 1,27 cm bei B4. Die relative Abweichung betrug für die Berechnung der Druckhöhe 2,19 % bei B5, 1,3 % bei B3 und ca. 5,3 % bei B4. Die Durchführung der Sensitivitätsanalyse der für die Modellierung relevanten Parameter zeigte eine sehr hohe Sensitivität der VAN GENUCHTEN-Parameter und der gesättigten hydraulischen Leitfähigkeit des Bodens. Darüber hinaus führten die Parameter nach DIN 4220 und die mithilfe von Pedotransferfunktionen aus Siebanalysen genommenen Parameter zu unterschiedlichen Ergebnissen. Im Rahmen des am Institut für Abfallwirtschaft und Altlasten durchgeführten Projektes EGSIM wurden die Programme SENSIT und ISSOP (in Zusammenarbeit mit DUALIS GmbH IT Solution) entwickelt und zur Parameteridentifikation/-kalibrierung benutzt. Die im Rahmen dieser Arbeit erzielten Ergebnisse konnten nachweisen, unter welchen Bedingungen eine Nachklärung des vollbiologisch gereinigten Abwassers innerhalb der Bodenzone möglich ist, so dass am Ort der Beurteilung (Grundwasseroberfläche) kein unzulässiger Schadstoffeintrag erfolgt. In Bezug auf die KKA-Feldmodelle ist die Anwendung des rotationssymmetrischen Koordinatensystems als Voraussetzung der Realität besser zu entsprechen und nicht als Option zu betrachten. Darüber hinaus wurden anhand der Feldmodelle verschiedene Szenarien mit kontinuierlicher und diskontinuierlicher Versickerung sowie zwei unterschiedlich großen Einleitflächen durchgeführt. Das Programm PCSiWaPro® ist sowohl für ungesättigte als auch für variabel-gesättigte porösen Medien anwendbar. Dies wurde im Rahmen der Simulation des Wasserhaushaltes eines Erddamms nachgewiesen. Die durchschnittliche relative Abweichung zwischen gemessenen und mittels PCSiWaPro® berechneten Wasserständen des entsprechenden Beobachtungspunkts im untersuchten Dammkörper lag bei 0,08 % (entspricht 5,8 cm bei einer Müchtigkeit von ca. 70 m) und das Bestimmtheitsmaß (R2) betrug 0,987. Die Simulation des Wasserhaushaltes unterschiedlicher Deponieabdichtungssystemen mittels PCSiWaPro® zeigte im Allgemeinen ein funktionierendes Ableiten des auf Deponien anfallenden Regenwassers (auch bei Starkregenereignissen). Darüber hinaus haben die durchgeführten Bewuchs-Modelle nachweisen können, dass die Vegetation der Deponieoberflächen den Wassergehalt, durch Pflanzenwurzelentzug bzw. Evapotranspiration, reduzieren können. Die Simulationsergebnisse der durchgeführten Szenarien des Wasserhaushaltes von Lysimetern zur prognostischen Berechnung der Grundwasserneubildung mittels PCSiWaPro® konnten nachweisen, dass das Programm für die Berechnung der Grundwasserneubildungsrate für diesen Zweck anwendbar ist. Die relativen Abweichungen der be-rechneten von den gemessenen Grundwasserneubildungsraten sind auf die verwendeten Materialparameter sowie auf Vernachlässigung der möglicherweise in Lysimetern sich befin-denden Makroporen (duale Porosität) zurückzuführen. / The modelling of complex systems such as the underground is a means to describe the processes occurring in the reality. The conducting of experiments on a model to obtain qualitative evidence about a real system is referred to as a simulation. Thereby, various models (e.g. physical and mathematical models) can be used. The unsaturated zone (vadose zone) is the region between the land surface and the water table, in which the water content is less than full saturation, and the pressure is lower than the atmospheric pressure. The unsaturated zone is very significant for agriculture, geobiology, aerobic degradation processes and groundwater recharge. The processes of water flow and solute transport in the unsaturated zone can be described by means of numerical simulation programs. The aim of the present work is a comprehensive validation of the simulation program PCSiWaPro® (developed at the TU-Dresden, Institute of Waste Management and Contaminated Site Treatment) for different applications. Another aim of this work is to investigate the applicability of the current version of PCSiWaPro® for different cases of a combination between the unsaturated zone and technical facilities. Four application cases with different objectives were investigated within the present work, which are: the simulation of decentralized wastewater infiltration with corresponding column and field experiments, the computation of groundwater recharge by means of lysimeters, the water balance of earth dams and the modelling of landfill covering systems. The application cases differ from each other by the objective of the simulation, the geometry, the size, the specified initial and boundary conditions, the simulation time, the applied materials, the coordinate system, the input and output data. The simulation results clearly showed that PCSiWaPro® is applicable for all investigated cases under consideration of different flow and solute transport regimes, parameters, boundary conditions, spatial and temporal discretization, and coordinate systems. The simulation results of the experimental soil columns for the decentralized treated wastewater infiltration case showed a very good agreement between measured and computed values of water and solute balance (pressure head, flow and solute concentration) of the investigated soil types B3 (slightly silty sand), B4 (coarse sand / gravel) and B5 (medium silty sand). The root of the mean squared error (RMSE) for the computation of the pressure head was 1,84 cm at B5, 3,61 cm at B3 and 1,27 cm at B4. The relative deviation in case of pressure head computation was 2,19 % at B5, 1,3 % at B3 and 5,3 % at B4. The implementation of the sensitivity analysis of the relevant parameters for the modelling showed a very high sensitivity of the VAN GENUCHTEN parameters and the saturated hydraulic conductivity of the soil. Moreover, the parameters according to DIN 4220 led to different results than the estimated ones according to pedotransfer methods based on sieve analysis. Within the project EGSIM, which was carried out at the Institute for waste management and contaminated sites treatment in collaboration with DUALIS GmbH IT Solution, the programs SENSIT and ISSOP were developed and used for parameter identification/ calibration. The results obtained in this Work showed under which conditions is a secondary treatment of full biologically treated wastewater in the soil possible, so that no unallowable pollutants entry in the groundwater occurs. With regard to the field models of this application the implementation of the rotationally symmetric coordinate system should be considered as a condition and not as an option for a better corresponding to the reality. Furthermore, different scenarios of the field models were carried out with continuous and discontinuous infiltration, as well as under different initiation areas. PCSiWaPro® could be applied for both unsaturated and variably-saturated porous media. This could be proven by the simulation of the water balance in an earth dam. The average relative deviation between measured and simulated water levels of the corresponding observation point in the investigated dam embankment was 0,08 % (corresponding to 5,8 cm at 70 m thickness) and the coefficient of determination (R2) was 0,987. In general, the simulation of the water balance using PCSiWaPro® of different landfill covering systems showed a successful draining of the falling rainwater (even under heavy rainfall). In addition, the implemented vegetation models have proven that the vegetation of the landfill surface can reduce the water content in the landfill by evapotranspiration and water uptake by roots. The water balance simulation results of the scenarios for the computation of groundwater recharge by means of lysimeters showed that the program is applicable for this case. The relative deviation of the simulated from the measured groundwater recharge rates occur due to the implemented material parameters as well as to the neglect of macro pores effects (dual porosity).