The applicability and adequacy of three modeling approaches to describe and predict breakthough curves (BTCs) for non-reactive solutes in statistically homogeneous porous media were numerically and experimentally investigated. Modeling approaches were: the convection-dispersion equation (CDE) with scale-dependent dispersivity, mobile-immobile model (MIM), and the fractional convection-dispersion equation (FCDE). In order to test these modeling approaches, a prototype laboratory column system was designed for conducting miscible displacement experiments with a free-inlet boundary. Its performance and operating conditions were rigorously evaluated. When the CDE with scale-dependent dispersivity is solved numerically for generating a BTC at a given location, the scale-dependent dispersivity can be specified in several ways namely, local time-dependent dispersivity, average time-dependent dispersivity, apparent time-dependent dispersivity, apparent distance-dependent dispersivity, and local distance-dependent dispersivity. Theoretical analysis showed that, when dispersion was assumed to be a diffusion-like process, the scale-dependent dispersivity was locally time-dependent. In this case, definitions of the other dispersivities and relationships between them were directly or indirectly derived from local time-dependent dispersivity. Making choice between these dispersivities and relationships depended on the solute transport problem, solute transport conditions, level of accuracy of the calculated BTC, and computational efficiency The distribution of these scale-dependent dispersivities over scales could be described as either as a power-law function, hyperbolic function, log-power function, or as a new scale-dependent dispersivity function (termed as the LIC). The hyperbolic function and the LIC were two potentially applicable functions to adequately describe the scale dependent dispersivity distribution in statistically homogeneous porous media. All of the three modeling approaches described observed BTCs very well. The MIM was the only model that could explain the tailing phenomenon in the experimental BTCs. However, all of them could not accurately predict BTCs at other scales using parameters determined at one observed scale. For the MIM and the FCDE, the predictions might be acceptable only when the scale for prediction was very close to the observed scale. When the distribution of the dispersivity over a range of scales could be reasonably well-defined by observations, the CDE might be the best choice for predicting non-reactive solute transport in statistically homogeneous porous media. / Ph. D.

A laboratory study of the mobility of Malathion in the soil environment was conducted. / Master of Science

Current treatment of wastewater can effectively remove the contaminants; however, the effluent is still not widely reused because of some undesired substances like pathogens and trace organic chemicals. To promote water reuse, membrane-based technologies have emerged as a robust and more efficient alternative to current treatment practice. Among these membrane processes, forward osmosis (FO) utilizes an osmotic pressure gradient across a semi-permeable membrane to reclaim high-quality water. Still, several key challenges remain to be addressed towards broader FO application, including energy-intensive draw regeneration to yield product water and salinity buildup in the feed solution. To bypass energy-intensive draw regeneration, commercial solid fertilizers was utilized as a regeneration-free draw solute (DS), harvesting fresh water towards direct agricultural irrigation. However, using nutrient-rich fertilizers as DS resulted in an elevated reverse solute flux (RSF). This RSF, known as the cross-membrane diffusion of DS to the feed solution, led to deteriorated solute buildup on the feed side, reduced osmotic driving force, increased fouling propensity, and higher operation cost. To effectively mitigate solute buildup while achieving energy-efficient water reclamation, a parallel electrodialysis (ED) device was integrated to FO for DS recovery in the feed solution. The salinity in the feed solution was consistently controlled below 1 mS cm-1 via the hybrid FO-ED system. Considering solute buildup is merely a consequence of RSF, direct control of RSF was further investigated via operational strategy (i.e., an electrolysis-assisted FO) and membrane modification (i.e., surface coating of zwitterion-functionalized carbon nanotubes). Significantly reduced RSF (> 50% reduction) was obtained in both approaches with minor energy/material investment. With two major bottlenecks being properly addressed for energy-efficient water reclamation, FO was further integrated with a microbial electrolysis cell (MEC) to achieve integrated nutrient-energy-water recovery from high-strength wastewater (i.e., the digestor centrate). The abovementioned research projects are among the earliest efforts to address multiple key challenges of FO during practical application, serving as a cornerstone to facilitate the transformation of current water/wastewater treatment plant to resource recovery hub in order to ensure global food-energy-water security. / Doctor of Philosophy / Exploring alternative water supply, for instance via reusing wastewater, will be essential to deal with the global water crisis. Current wastewater treatment can effectively remove the contaminants; however, the treated wastewater is still not widely reused due to the possible presence of residual contaminants. In recent years, membrane-based technologies have emerged as a promising treatment process to produce clean water. Among all available membrane technologies, forward osmosis (FO) takes advantage of the osmotic pressure difference across a special membrane to extract fresh water from a low-salinity FEED solution (for example, wastewater) to a high-salinity DRAW solution. The reclaimed fresh water can be reused for other applications. Still, the FO process is facing several critical challenges for broader applications. The first challenge is that additional energy is required to separate clean water from the diluted DRAW solution, leading to notably increased energy consumption for the FO process. To bypass this energy-intensive separation, commercial solid fertilizers was utilized as a separation-free DRAW solution for FO process. Once the clean water is extracted to the DRAW solution (fertilizer), the diluted fertilizer solution together with the fresh water can be directly used for agricultural irrigation. The second challenge is that, when fertilizer is applied as the DRAW solution, nutrient rich fertilizers can penetrate the FO membrane and escape to the FEED solution (wastewater). This phenomenon is known as the reverse solute flux (RSF). RSF can result in many adverse effects, such as wastewater contamination and increased operational cost. To prevent this, we used an additional device named electrodialysis to effectively recapture the “escaped” fertilizers in the FEED solution. Besides this indirect approach to recover escaped fertilizers, we also investigated direct approaches to control RSF, including operational strategy and membrane modification. With two major challenges being properly addressed for energy-efficient water reclamation, FO was further combined with a microbial electrolysis cell (MEC) to achieve multiple resource recovery from wastewater, including water, nutrient, and energy components. The above mentioned research projects are among the earliest efforts to address multiple key challenges of FO during water and resource recovery from wastewater to ensure global food-energy-water security.

In cells and organelles transporters are responsible for translocation of amino acids, sugars and nucleotides among others. In the central nervous system (CNS), amino acid transporters can function as neurotransmitter transporters and nutrient sensors. The Solute carrier (SLC) superfamily is the largest family of transporters with 395 members divided in 52 families. The system A and system N amino acid transporter family, SLC38, consists of 11 members, SNAT1-11 (SLC38A1-11). The members are expressed in the brain, exclusively in neurons or astrocytes and some in both. Amino acid signaling is mainly regulated via two pathways, the amino acid responsive (AAR) pathway and the mechanistic/mammalian target of rapamycin complex 1 (mTORC1) pathway. These pathways regulate the protein synthesis in opposite directions depending on the amino acid availability. SLC38 members along with other SLCs have been identified to participate in these pathways. In paper I, the regulation of SLC genes after complete amino acid starvation in mouse hypothalamic cells have been studied with microarray and we found that 47 SLC genes were significantly altered at five hours of starvation. Interestingly, we found that Slc38a1 and Slc38a7 were upregulated along with the known starvation responding gene, Slc38a2. A complementary starvation study for the SLC38 genes was performed using primary mouse embryonic cortex cells. We found that Slc38a1, Slc38a2, Slc38a5, Slc38a6 and Slc38a8 were upregulated while Slc38a3, Slc38a7 and Slc38a11 were downregulated. Three members from the SLC38 family, SNAT8 (paper IV), SNAT9 (paper III) and SNAT10 (paper II) have been histologically characterized in mouse brain and all these transporters are exclusively neuronal. SNAT8 and SNAT10 were also functionally characterized and shown to be transporters for alanine and glutamine among others. SNAT8 was shown to mediate sodium dependent transport and was classified to system A. SNAT10 was shown to be a sodium independent bidirectional transporter and displayed characteristics for system A and N. SNAT9 is a lysosomal component of the Ragulator-Rag complex which senses amino acid availability and activates mTORC1. In paper III we also found that Slc38a9 gene expression was upregulated following starvation and downregulated following high-fat diet in mouse brain.

Em vacas de corte, folículos pré-ovulatórios (FPO) maiores, maiores concentrações de estradiol (E2) no proestro/estro e progesterona (P4) no diestro favorecem o crescimento do concepto e a fertilidade. Porém, os mecanismos mediados pelos esteroides femininos que influenciam a receptividade uterina ao embrião precisam ser esclarecidos. Os aminoácidos (AA) são componentes das secreções uterinas que são cruciais para a sobrevivência do embrião antes da implantação. A hipótese deste trabalho é que o tamanho do FPO e as concentrações de E2 e P4 modulam a abundância de transcritos relacionados ao transporte e metabolismo de AA no endométrio e afetam a concentração luminal de AA. Para isso, o crescimento folicular de vacas Nelore foi manipulado com o objetivo de formar dois grupos: FPO grande e CL grande (FG-CLG) e FPO pequeno e CL pequeno (FP-CLP). No Dia 4 (D4; Exp 1) e Dia 7 (D7; Exp 2) após a injeção de GnRH para indução da ovulação, foram coletados tecido endometrial e lavado uterino post-mortem. A abundância de transcritos foi avaliada por qRT-PCR e as concentrações de AA nos lavados foram quantificadas por HPLC. No Exp 1, o tamanho do FPO, concentrações plasmáticas de E2 no D-1 e de P4 no D4 foram 15,70mm±0,43 vs. 11,31mm±0,23 (p<0,01), 2,44pg/ml±0,19 vs. 0,65pg/ml (p<0,01) e 1,40ng/ml±0,23 vs. 0,80ng/ml±0,10 (p<0,01) para os grupos FG-CLG vs. FP-CLP, respectivamente. No Exp 2, o tamanho do FPO, concentrações plasmáticas de E2 no D-1 e de P4 no D7 foram 13,18mm±0,44 vs. 10,63mm±0,30 (p<0,01), 2,30pg/ml±0,57 vs. 0,50pg/ml±0,13 (p<0,01) e 3,68ng/ml±0,38 vs. 2,49ng/ml±0,43 (p=0,04) para os grupos FG-CLG vs. FP-CLP, respectivamente. No D4 a abundância de SLC1A4, SLC38A1, SLC6A6, SLC7A4 e SLCY e no D7, SLC1A4, SLC6A1, SLC6A14, SLC7A4, SLC7A8, SLC38A1, SLC38A7, SLC43A2 e DDO foi maior no endométrio dos animais do grupo FG-CLG (p<0,05). No D4, maiores concentrações de taurina, alanina e ácido α-aminobutírico foram observadas no grupo FP-CLP (p<0,05). Em contraste, menores concentrações de valina e cistationina foram encontradas nos lavados uterinos do D7 dos animais do grupo FP-CLP (p<0,05). No D4, os animais do grupo FG-CLG, associado a maior fertilidade, apresentaram menor quantidade de AA nas secreções uterinas, porém, a abundância dos transportadores de AA foi compatível com maior transporte em comparação aos animais do grupo FP-CLP. Esses resultados sugerem que antes do embrião se mover do oviduto ao útero, o transporte e metabolismo dos AA prioriza a preparação das células endometriais para receber o embrião e não o acúmulo nas secreções uterinas. Porém, no D7, quando o embrião está em contato direto com as secreções uterinas, os genes relacionados ao transporte de AA no endométrio e a concentração de AA no histotrofo são estimulados nas vacas do grupo FG-CLG. Portanto o metabolismo e transporte de AA no sentido das células endometriais ou das secreções uterinas pode ser um mecanismo importante para a receptividade materna. / In beef cattle, a large size of the pre-ovulatory follicle (POF) and resulting elevated proestrus/estrus estradiol (E2) and diestrus progesterone (P4) concentrations positively affect conceptus growth and fertility. However, sex-steroid-mediated mechanisms that influence uterine receptivity to the embryo need to be elucidated. Amino acids are important components of maternally-derived secretions that are crucial for embryo survival before implantation. The hypothesis is that the size of the POF, E2 and P4 concentrations modulate endometrial abundance of solute carrier proteins (SLC) transcripts related to AA transport and metabolism and subsequently affect lumenal amino acids concentrations. Therefore, follicle growth of Nelore cows was manipulated to produce two experimental groups: large POF and CL (LF-LCL group) and small POF and CL (SF-SCL group). On Day 4 (D4; Experiment 1) and Day 7 (D7; Experiment 2) post GnRH injection to induce ovulation, endometrial tissue and uterine washings were collected post-mortem. Transcript abundance was evaluated by qRT-PCR and amino acid concentrations were quantified in washings by HPLC. On Experiment 1, POF size, plasma E2 concentration on D-1, and plasma concentration of P4 on D4 were 15.70mm±0.43 vs. 11.31mm±0.23 (p<0.01), 2.44pg/ml±0.19 vs. 0.65pg/ml (p<0.01) and 1.40ng/ml±0.23 vs. 0.80ng/ml±0.10 (p<0.01) for the LF-LCL vs. SF-SCL groups, respectively. For Experiment 2, POF size, plasma E2 concentration on D-1 and plasma P4 concentration on D7 were 13.18mm±0.44 vs. 10.63mm±0.30 (p<0.01), 2.30pg/ml±0.57 vs. 0.50pg/ml±0.13 (p<0.01) and 3.68ng/ml±0.38 vs. 2.49ng/ml±0.43 (p=0.04) for the LF-LCL vs. SF-SCL groups, respectively. On D4, abundance of SLC6A6, SLC7A4, SLC17A5, SLC38A1, SLC38A7 and SLCY and on D7, SLC1A4, SLC6A1, SLC6A14, SLC7A4, SLC7A7, SLC7A8, SLC17A5, SLC38A1, SLC38A7, SLC43A2 and DDO was greater in the endometrium of cows from the LF-LCL group (p<0.05). On D4, higher concentrations of taurine, alanine and α-aminobutiric acid were observed in SF-SCL (p<0.05). In contrast, lower concentrations of valine and cystathionine were quantified in D7 uterine washings from SF-SCL cows (p<0.05). On D4, animals from LF-LCL group, associated with greater fertility, presented less amino acid content in uterine secretion but abundance of transporters was compatible to greater transport in comparison to animals from SF-SCL group. This suggests that before embryo moves from oviduct to uterus, amino acids transport and metabolism pathways prioritizes endometrium cells preparation for receiving the embryo but not accumulation in uterine secretions. However, on D7, when the embryo is in direct contact with uterine secretions, genes related to amino acids transport in endometrium and amino acids concentration in histotroph are up-regulated in LF-LCL cows. The latter insights indicate that amino acids metabolism and transport, towards endometrial cells or uterine secretions, might be mechanisms contributing to maternal receptivity.

Esta dissertação apresentou um estudo dos mecanismos de transporte de sódio, fosfato e amônio em colunas indeformadas de material inconsolidado residual de arenitos da Formação Adamantina. Em campo foi realizada caracterização táctil visual do material, alem de ensaios de condutividade hidráulica. Em laboratório, realizou-se ensaio de coluna em material indeformado, para que fossem obtidos os parâmetros de fluxo de água: velocidade linear media, velocidade de Darcy, vazão e condutividade hidráulica. Também foram obtidos os coeficientes de dispersão hidrodinâmica dos três íons estudados por meio de quatro métodos. Os fatores de retardamento dos íons foram obtidos por meio de três métodos. Para auxiliar nas analises, o solo foi caracterizado mineralógica, química, física e físico-quimicamente. Adicionalmente foram feitas analises da poro simetria e estudo das trajetórias de transporte. As informações foram integradas para que fosse possível analisar os parâmetros de transporte de solutos no solo. Com esta pesquisa percebeu-se que o uso dos parâmetros de transporte em modelagem do transporte de contaminantes deve ser feito com cautela, observando tanto as características do solo (mineralógicas, físicas, físico-químicas) quanto os modelos conceituais e as limitações dos métodos utilizados. / This research aimed to study the transport mechanisms of sodium, phosphate and ammonium in undisturbed columns of unconsolidated residual material of the sandstones from the Adamantina Formation. At field, visual and tactile characterization of the material were performed as well as hydraulic conductivity tests . At laboratory, there were made column tests in undisturbed samples to obtain the parameters of water flow, i.e., average linear velocity, Darcy velocity, flow rate and hydraulic conductivity. Hydrodynamic dispersion coefficients of every studied ion were determined using four methods. The retardation factors of the three ions were obtained using three methods. To assist the analysis, the soil was mineralogical, chemistry, physically and physic-chemically characterized. We also analyzed the water retention curve, mercury intrusion porosimetry and solute transport trajectories. All available data were integrated for analyzing the parameters of solute transport in soil. The results showed that the use of transport parameters in modeling of contaminant transport should be done with caution, observing soil characteristics, the conceptual models and the limitations of the methods used.

Com o avanço dos computadores pessoais, problemas técnicos complexos, antes restritos aos grandes centros de pesquisas internacionais, passam a ser acessíveis pelas mais diversas áreas do conhecimento, como as engenharias e em particular a Engenharia Química. Fenômenos físicos são representados matematicamente por equações diferenciais, que na maioria das vezes não possuem solução analítica possível. O CFD ( Computer Fluid Dynamics) é uma técnica numérica iterativa, que busca a solução destas equações diferenciais através da discretização do domínio estudado e das equações que governam o fenômeno envolvido. Neste trabalho, através de um software especialista de CFD, o ANSYS CFX 11.0, foi simulado o transporte de massa e momento de um soluto traçador, o Cloreto, presente no sal Cloreto de Sódio, em um meio poroso. Em seguida, os resultados desta simulação foram comparados e validados por um experimento de transporte de massa numa caixa de areia. / With the advance of the personal computers, complex technical problems, before restricted to the huge centers of international researches, have become more accessible by many areas of the knowledge, like the engineering and in particular the Chemical Engineering. Physical phenomena are represented mathematically by differentials equations, which most of the time do not have possible analytical solution. CFD (Computer Fluid Dynamics) is an iterative numeric technique, which search the solution of these differentials equations through both discretization of the studied domain and the equations that govern the involved phenomenon. In this work, through a CFD\'s specialist software, ANSYS CFX 11.0, it was simulated the mass and momentum transport of a solute tracer, Chloride, present in Sodium Chloride, in a porous media. After this, the simulations results were compared and validated in a mass transport experiment in a sand box.

Nos últimos anos grande número de modelos computacionais tem sido propostos com o intuito de descrever o movimento de solutos no perfil do solo, apesar disso, o que se observa é que existe grande dificuldade em se modelar esses fenômenos, para que o modelo possa predizer o processo de deslocamento e retenção dos solutos na natureza. Para tanto, o objetivo deste trabalho foi utilizar um modelo estatístico para descrever o transporte dos solutos no perfil do solo. Dessa forma, foi realizado um experimento em laboratório e observado os níveis de potássio e nitrato ao longo do perfil dos solos Latossolo Vermelho Amarelo e Nitossolo Vermelho. Para inferir sobre essas variáveis foram consideradas duas abordagens. Para a primeira abordagem foi utilizado um modelo de regressão não linear para cada uma das variáveis, cujos parâmetros do modelo apresentam uma interpretação prática, na área de solos. Para esse modelo foi realizado um esboço sobre a não linearidade do mesmo para verificar as propriedades assintóticas dos estimadores dos parâmetros. Para o método de estimação foi considerado, o método de mínimos quadrados e o método de bootstrap. Além disso, foi realizada uma análise de diagnóstico para verificar a adequação do modelo, bem como identificar pontos discrepantes. Por outro lado, para outra abordagem, foi utilizado um modelo multiresposta para analisar o comportamento das variáveis nitrato e potássio ao longo do perfil dos solos, conjuntamente. Para esse modelo foi utilizado o método da máxima verossimilhança para encontrar as estimativas dos parâmetros do modelo. Em ambas as situações, observou-se a adequação dos modelos para descrever o comportamento dos solutos nos solos, sendo uma alternativa para os pesquisadores que trabalham com estudo de solos. O modelo logístico com quatro parâmetros se destacou por apresentar melhores propriedades, como medidas de não linearidade e boa qualidade de ajuste. / In the last years, several computational models have been proposed to describe the movement of solutes in the soil profile, but what is observed is that there is great difficulty in model these phenomena, so that model can predict the displacement process and retention of solutes in nature. Thus, the aim of this study was to use a statistical model to describe the transport of solutes in the soil profile. Therefore, an experiment was conducted in the laboratory and observed levels of potassium and nitrate along the depth of soil Oxisol (Haplustox) and Hapludox,. To make inferences about these variables were considered two approaches. For the first approach was utilized a non-linear regression model for each variable and the model parameters have a practical interpretation on soil. For this model we performed a sketch on the nonlinearity of the model to check the asymptotic properties of parameter estimators. To estimate the parameters were considered the least squares method and the bootstrap method. In addition, we performed a diagnostic analysis to verify the adequacy of the model and identify outliers. In the second approach considered was using a multi-response model to analyze the behavior of the variables nitrate and potassium throughout the soil profile together. For this model we used the maximum likelihood method to estimate the model parameters. In both cases, we observed the suitability of the models to describe the behavior of solutes in soils, being an alternative for researchers working on the study of soils. The logistic model with four parameters stood out with better properties, such as non-linearity and good fit.

As características hidráulicas do solo têm uma importância fundamental relacionada à disponibilidade de água para as plantas e ao transporte de solutos no solo. O modelo bifásico ou "móvel-imóvel" presume que o teor de água no solo (θ) pode ser dividido em duas frações: uma fração móvel (θm) e uma outra imóvel (θim). Define-se mobilidade μ da água no solo como a razão θm/θ. Correlações entre as funções θ(h), K(h) e μ(h) são esperadas, uma vez que essas três propriedades são relacionadas com a mesma estrutura do sistema poroso do solo. O objetivo do presente trabalho foi apresentar uma hipótese correlacionando a função mobilidade com a de condutividade, e testá-la através de dados obtidos segundo uma metodologia de laboratório desenvolvida. O experimento foi realizado em Piracicaba, SP e em Braunschweig, Alemanha. Amostras indeformadas de cinco solos (Latossolo Vermelho-Amarelo, no Brasil e Orthic Luvisol, Stagno-gleyic Luvisol, Dystric Podzoluvisol e Gleyic Podzoluvisol, na Alemanha) foram coletadas para a determinação das propriedades hidráulicas de retenção e mobilidade da água no solo. O método utilizado para a determinação da mobilidade da água consistiu na aplicação de um volume de água contendo o íon Cl- como traçador (um "pulso hidráulico") à amostra de solo sob sucção com o objetivo de simular eventos de chuva ou irrigação, que promovem uma alteração hidráulica rápida no solo. A difusão do íon entre as frações móvel e imóvel foi considerada desprezível, uma vez que o pulso hidráulico foi aplicado em uma única parcela e diretamente no solo, tornando o processo relativamente rápido. Resultados obtidos nos cinco solos avaliados indicam a existência de uma correlação linear entre μ e o valor de K/(dK/dθ), conforme hipotetizado. Utilizando o sistema de equações de Van Genuchten – Mualem, μ(h) pode portanto ser estimado por parâmetros da curva de retenção. A metodologia proposta permitiu a determinação da mobilidade da água em amostras de solo sob condições laboratoriais. A mobilidade da água mostrou ser uma função do volume relativo (v) aplicado podendo a relação μ – v ser parametrizada pelo ajuste de uma equação simples, com apenas um parâmetro. Não foi possível averiguar a existência de uma relação empírica entre esse parâmetro e os parâmetros da equação de Van Genuchten, possivelmente em função do número pequeno de dados disponíveis. / Soil hydraulic properties are essential for the determination of plant water availability and solute transport into the soil. The biphasic or mobile-immobile model concept assumes the soil water content (θ) to be divided in two fractions: a mobile fraction (θm) and an immobile fraction (θim). Soil water mobility, μ is defined as the ratio θm/&#952. Relationships between θ (h), K(h) e μ (h) are probable since these properties are related to the same soil pore structure. The objective of this study was to test a hypothesis regarding a correlation between the mobility function and the hydraulic conductivity function, using a new developed laboratory method to determine soil water mobility. The experiments were conducted in Piracicaba, Brazil and in Braunschweig, Germany. Undisturbed soil samples were collected in five soils (Oxisol, in Brazil, Orthic Luvisol, Stagno-gleyic Luvisol, Dystric Podzoluvisol e Gleyic Podzoluvisol, in Germany) to determine hydraulic properties and soil water mobility. The method used to determine water mobility consists in a water volume with Cl- ion as a tracer ("hydraulic pulse") applied to a soil sample under suction, simulating a rainfall or irrigation event leading to abrupt hydraulic changes. The ion diffusion between the mobile and immobile water fractions was negligible as the hydraulic pulse was applied directly to the soil in a relatively short process. Results of five evaluated soils indicate the existence of a linear correlation between μ and K/(dK/d θ), confirming the hypothesis. Using the Van Genuchten – Mualem equation system, μ(h) can therefore be estimated by retention curve parameters. The proposed laboratory method allowed determining soil water mobility in soil samples under laboratory. Soil water mobility showed to be a function of the applied relative volume (v), while the relationship μ – v could be modeled by a simple, one-parameter equation, however, it was not possible to verify the existence of an empirical relation between this parameter and parameters from the Van Genuchten equation, possibly due to small number of available data.

Com o avanço dos computadores pessoais, problemas técnicos complexos, antes restritos aos grandes centros de pesquisas internacionais, passam a ser acessíveis pelas mais diversas áreas do conhecimento, como as engenharias e em particular a Engenharia Química. Fenômenos físicos são representados matematicamente por equações diferenciais, que na maioria das vezes não possuem solução analítica possível. O CFD ( Computer Fluid Dynamics) é uma técnica numérica iterativa, que busca a solução destas equações diferenciais através da discretização do domínio estudado e das equações que governam o fenômeno envolvido. Neste trabalho, através de um software especialista de CFD, o ANSYS CFX 11.0, foi simulado o transporte de massa e momento de um soluto traçador, o Cloreto, presente no sal Cloreto de Sódio, em um meio poroso. Em seguida, os resultados desta simulação foram comparados e validados por um experimento de transporte de massa numa caixa de areia. / With the advance of the personal computers, complex technical problems, before restricted to the huge centers of international researches, have become more accessible by many areas of the knowledge, like the engineering and in particular the Chemical Engineering. Physical phenomena are represented mathematically by differentials equations, which most of the time do not have possible analytical solution. CFD (Computer Fluid Dynamics) is an iterative numeric technique, which search the solution of these differentials equations through both discretization of the studied domain and the equations that govern the involved phenomenon. In this work, through a CFD\'s specialist software, ANSYS CFX 11.0, it was simulated the mass and momentum transport of a solute tracer, Chloride, present in Sodium Chloride, in a porous media. After this, the simulations results were compared and validated in a mass transport experiment in a sand box.