Alexandre Botari | Universidade Estadual de Maringa (original) (raw)
Papers by Alexandre Botari
Brazilian Archives of Biology and Technology, Dec 31, 2022
Anthropic activities have been causing serious impacts in aquatic environments, deteriorating the... more Anthropic activities have been causing serious impacts in aquatic environments, deteriorating the quality of the waters. Superficial springs with excess of nutrients, rich in compounds of phosphor and nitrogen, may induce blooms of algae and cyanobacteria, hard to be removed in the treatment of water. Such microscopic particles, e.g. Microcystis spp., are named biocolloids. This work propose to apply the mathematical modelling by the extended colloidal XDLVO theory (Extended Derjarguin-Landau-Verwey-Overbeek) for coagulation and gravel upflow filtration (GUF) and sand downflow rapid filtration (SDRF) to the technology of double filtration applied to study water containing Microcystis spp. The XDLVO theory has been shown to be efficient at evaluating the behavior of the colloidal particles as a function of the separation distance, making apparent how the intermolecular and surface forces act: acid-base interaction (AB), Lifshitz-Vander Walls (vdW), double electric layer (DEL) and Born repulsion forces. Such forces that act in this colloidal system formed by Microcystis spp. were analyzed in terms of their mutual interaction and their interaction with porous environments in double filtration at the stable thermodynamic situations (precoagulation) and at unstabilized by the chemical coagulation. The raw water energetic barrier of repulsion and after the sand downflow rapid filtration gave an average decreasing of about 90% in absolute values. • The application of mathematical models allows the study of complex environments. • The chemical coagulant acts on electrostatic destabilization, decreasing the absolute value of the electrical potential of the electrical double layer. • The XDLVO theory is efficient in studying the behavior of energies and interaction forces along the particle separation distance.
Acta Scientiarum. Technology, 2012
Models of the filtration phenomenon describe the mass balance in bed filtration in terms of parti... more Models of the filtration phenomenon describe the mass balance in bed filtration in terms of particle removal mechanisms, and allow for the determination of global particle removal efficiencies. These models are defined in terms of the geometry and characteristic elements of granule collectors, particles and fluid, and also the composition of the balance of forces that act in the particle collector system. This work analyzes particles collection efficiency comparing downflow and upflow direct filtration, taking into account the contribution of the gravitational factor of the settling removal efficiency in future proposal of initial collection efficiency models for upflow filtration. A qualitative analysis is also made of the proposal for the collection efficiency models for particle removal in direct downflow and upflow filtration using a Computational Fluid Dynamics (CFD) tool. This analysis showed a strong influence of gravitational factor in initial collection efficiency (t = 0) of particles, as well as the reasons of their values to be smaller for upflow filtration in comparison with the downflow filtration.
Análise De Modelo Matemático Monodisperso Para a Remoção De Partículas Na Filtração Utilizando Método De Levenberg-Marquardt
Mathematical modeling for models monodisperse suspensions removal constitutes a challenge in term... more Mathematical modeling for models monodisperse suspensions removal constitutes a challenge in terms of both complexity algorithmic and computational performance depending on the complexity of the interrelationships between the particles of various sizes and spatial configurations. The present work analyzes the efficiency of particle removal by comparing the direct up and down filtration, a mathematical model of monodisperse particle removal in filtration, using the method of Levenberg-Marquardt. Double filtration tests were used on a pilot scale, with data filtering up and quick filter descendant to the sensitivity analysis and calibration of models. Disparate results were obtained with the regression coefficient for multivariate equations (R2) of the order of 50% up to 99% of adherence to experimental data. These results indicate the feasibility of models and the need for further studies in the subject. Index Terms – flocculation, mathematical modelling, re-flocculation, aggregation...
Acta Scientiarum. Technology, 2015
Mathematical models of the filtration process are based on the mass balance in the filter bed. Mo... more Mathematical models of the filtration process are based on the mass balance in the filter bed. Models of the filtration phenomenon describe the mass balance in bed filtration in terms of particle removal mechanisms, and allow for the determination of global particle removal efficiencies. This phenomenon is defined in terms of the geometry and the characteristic elements of granule collectors, particles and fluid, and the composition of the balance of forces that act in the particle collector system. This type of resolution is well known as the trajectory analysis theory. Particle trajectory analysis by mathematical correlation of the dimensionless numbers that represent fluid and particle characteristics is considered the main approach for mathematically modeling the initial collection efficiency of particle removal in water filtration. The existing initial collection efficiency models are designed for downflow filtration. This study analyzes initial collection efficiency models, and proposes an adaptation of these models to direct upflow filtration in a granular bed of coarse sand and gravel, taking into account the contribution of the gravitational factor of the settling removal efficiency in the proposal of initial collection efficiency models.
Avaliação Sazonal Do Conforto Ambiental Térmico Em Espaços Públicos Abertos No Município De Umuarama-PR
Having the user as “figure” inserted in the environment, the importance of open public spaces whi... more Having the user as “figure” inserted in the environment, the importance of open public spaces while landscapes built gains haste with the world trend to promote the sustainability of these spaces. The focus is on environmental variables of comfort which is the fundamental premise for the permanence and the multiple uses of these open spaces of local cultural and social references. However, research is scarce relating to environmental agents. Thermal well-being in these spaces is of fundamental importance. In the city of Umuarama-PR there are currently thirty public squares, the squares will be addressed in this work representative located in Avenida Brazil, a major axis of the city which covers the squares Santos Dumont, John Paul VI and Plaza Brasilia. Will be presented an analysis of the seasonal evaluation in terms of measurements of the variables of luminous intensity and relative humidity at various points of the above mentioned squares. Keywords - squares, seasonal evaluation,...
Ambiente e Agua - An Interdisciplinary Journal of Applied Science, 2022
Environmental pollution is a worldwide concern, especially when caused by sewage dumping into wat... more Environmental pollution is a worldwide concern, especially when caused by sewage dumping into water bodies. Many substances are present in industrial or domestic wastewater, causing contamination in superficial water collection. Surfactants stand out for being widely used both industrially and domestically. The use of detergents and many types of surfactants was increased during the Covid-19 pandemic period, a fact observed in the levels in the effluent sample analysis from a Sewage Treatment Plant (STP) - Vila City around 21 and 39 mg L-1 in this period. This work evaluated the surfactant concentrations in the primary and secondary treatment units of the Vila City STP, in the city of Paranavaí-PR.-Brazil. In addition, the use of a post-treatment by slow sand filtration and adsorption by activated carbon produced from spent coffee grounds in the complementary removal of surfactants was proposed. A mixed bed with sand and activated carbon columns was made on a pilot scale, and filtr...
Brazilian Journal of Health Review, 2022
Avaliar a eficiência dos processos em uma Estação de Tratamento de Esgoto (ETE) é um instrumento ... more Avaliar a eficiência dos processos em uma Estação de Tratamento de Esgoto (ETE) é um instrumento fundamental na busca de uma sociedade mais sustentável. Este trabalho procurou avaliar parâmetros menos comuns, mas muito importantes para o equilíbrio sustentável do corpo hídrico receptor deste efluente, ainda que tratado: a DQO (demanda química de oxigênio), os surfactantes e os óleos e graxas. Foram avaliadas as concentrações destes parâmetros em diferentes etapas do processo de tratamento de esgoto da ETE Vila City, na cidade de Paranavaí-PR com o objetivo de se verificar a eficiência dos processos utilizados no tratamento do esgoto para adequação das concentrações destes aos valores referenciados pela legislação brasileira de lançamento de efluentes na coleção hídrica. Os valores obtidos para concentração destes parâmetros no período estudado indicam: remoção de cerca de 73% na concentração de DQO; remoção de cerca de 30% na concentração de óleos e graxas; média de remoção de cerca de menos de 8% na concentração de surfactantes. Palavras-chave: efluente, estação de tratamento de esgoto, sustentabilidade.
This paper proposes to present an application of CFD programs in a simulation of the flow in a hy... more This paper proposes to present an application of CFD programs in a simulation of the flow in a hydraulic jump. Initially, it has been introduced the nonlinear representative equations of the flow and the turbulence models necessary to solve Navier-Stokes equations. Therefore, it will be demonstrated how to resolve theses equations using the numerical methods by means of discretisetion and system solve. Finally, it will be shown a transient problem application in a simulation of a hydraulic jump of horizontal channel. The turbulence model used for proposed problem resolution was the Reynolds Stress Model (RSM), which better represents the physical flow characteristics of the problem. A comparison of the numerical results with experimental data has showed two different behaviors: the free surface in the experimental data presents the level of upstream agreement higher than in the hydraulic jump, therefore, in the first one the experimental data line was immerged in to 90% of volume fr...
31st Annual Frontiers in Education Conference. Impact on Engineering and Science Education. Conference Proceedings (Cat. No.01CH37193), 2001
In a Country like Brazil, more than ever it is necessary to increase the number of researchers, c... more In a Country like Brazil, more than ever it is necessary to increase the number of researchers, committed with environment principally because this Country has an immense challenge to defeat: to promote development for the welfare of people without forgetting the human aspects involved in the relations-man, progress and nature. So it is imperative the creation of alternatives for the qualification of scientific minds to make science and create technology. This project consists in a proposal of an Environmental Engineering Program, conceived by the Coordinating Team of Engineering School of Lusiada University Center. It is a five years program, having in its curriculum some new courses of modern sciences, besides the ones demanded by the Education Law of Brazil, for engineering programs. It is a modular education, developed in periods, called "theoretical modules" and "search modules". They last four months each and they are complimentary. At the end of the Program s/he will be an engineer capable to promote human welfare contributing to decrease the grade of the impact of progress over nature and even over men.
Engenharia Sanitaria e Ambiental, 2012
Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de fo... more Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de forças e balanço de energia de complexos coloidais na água bruta e daqueles formados durante a filtração direta em escoamento ascendente. Nele são descritos os perfis de energia de interação entre as superfícies dos colóides para três geometrias: esférica, plana e cilíndrica; e quatro arranjos de interação entre as superfícies: dois cilindros, dois planos, duas esferas e uma esfera e um plano. Duas situações foram analisadas, antes e após a desestabilização eletrostática pela ação de sulfato de alumínio em águas de estudo contendo caulinita, utilizando-se a modelação e análise pela teoria DLVO (das iniciais de Derjarguin-Landau-Verwey-Overbeek) modificada, ou XDLVO, que inclui à abordagem tradicional das forças da dupla camada elétrica (DCE), forças de atração de superfície ou London-van der Waals (LvdW), forças estéricas, força hidrofóbica e forças de outras origens no cálculo do balanço ...
Engenharia Sanitaria e Ambiental, 2012
Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de fo... more Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de forças e balanço de energia de complexos coloidais na água bruta e daqueles formados durante a filtração direta em escoamento ascendente. Nele são descritos os perfis de energia de interação entre as superfícies dos colóides para três geometrias: esférica, plana e cilíndrica; e quatro arranjos de interação entre as superfícies: dois cilindros, dois planos, duas esferas e uma esfera e um plano. Duas situações foram analisadas, antes e após a desestabilização eletrostática pela ação de sulfato de alumínio em águas de estudo contendo caulinita, utilizando-se a modelação e análise pela teoria DLVO (das iniciais de Derjarguin-Landau-Verwey-Overbeek) modificada, ou XDLVO, que inclui à abordagem tradicional das forças da dupla camada elétrica (DCE), forças de atração de superfície ou London-van der Waals (LvdW), forças estéricas, força hidrofóbica e forças de outras origens no cálculo do balanço ...
Radiologia Brasileira, 2005
dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É... more dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É formado pelo decaimento radioativo do 226 Ra, um descendente do urânio (238 U), o qual é encontrado em quantidades variadas em solos, rochas e águas (2,3). O 222 Rn se desintegra por emissão de partícula alfa (T 1/2 = 3,82 dias), originando uma cadeia de decaimento conhecida como filhos ou descendentes do radônio. Por ser um gás, o radônio produzido no interior de rochas e solos difunde-se com facilidade através de fissuras, tubulações, buracos e lençóis freáticos até alcançar a superfície terrestre (4). Dessa forma, altas concentrações de 222 Rn podem ocorrer em ambientes fechados ou pouco ventilados e, assim, representar risco potencial à saúde
Modelação matemática macroscópica da perda de carga e da remoção de sólidos suspensos totais na filtração direta ascendente; Macroscopic mathematical …
Eng. sanit. ambient, 2007
Resumo: A utilização de um modelo matemático permite a obtenção de condições otimizadas de operaç... more Resumo: A utilização de um modelo matemático permite a obtenção de condições otimizadas de operação, o que conduz à melhoria do controle e da previsão do processo de filtração. Os modelos matemáticos descrevem o processo de filtração através dos ...
Radiologia Brasileira, 2005
dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É... more dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É formado pelo decaimento radioativo do 226 Ra, um descendente do urânio (238 U), o qual é encontrado em quantidades variadas em solos, rochas e águas (2,3). O 222 Rn se desintegra por emissão de partícula alfa (T 1/2 = 3,82 dias), originando uma cadeia de decaimento conhecida como filhos ou descendentes do radônio. Por ser um gás, o radônio produzido no interior de rochas e solos difunde-se com facilidade através de fissuras, tubulações, buracos e lençóis freáticos até alcançar a superfície terrestre (4). Dessa forma, altas concentrações de 222 Rn podem ocorrer em ambientes fechados ou pouco ventilados e, assim, representar risco potencial à saúde
Engenharia Sanitaria e Ambiental, 2005
A metodologia encontrada na literatura para a otimização do gradiente de velocidade médio em reat... more A metodologia encontrada na literatura para a otimização do gradiente de velocidade médio em reatores de mistura completa, com câmaras em série de escoamento contínuo, a partir de ensaios em reator estático tipo jarteste, baseia-se em modelos matemáticos que descrevem a cinética dos encontros entre partículas durante a floculação. Considerando-se que a aplicabilidade desta metodologia tem-se revelado inconsistente, como observado por diversos autores, este trabalho propõe uma metodologia racional para utilizar e otimizar os dados experimentais obtidos em reatores estáticos e, utilizando modelos matemáticos, obter dados para o projeto de floculadores mecanizados em série em estações de tratamento de água.
Brazilian Archives of Biology and Technology, Dec 31, 2022
Anthropic activities have been causing serious impacts in aquatic environments, deteriorating the... more Anthropic activities have been causing serious impacts in aquatic environments, deteriorating the quality of the waters. Superficial springs with excess of nutrients, rich in compounds of phosphor and nitrogen, may induce blooms of algae and cyanobacteria, hard to be removed in the treatment of water. Such microscopic particles, e.g. Microcystis spp., are named biocolloids. This work propose to apply the mathematical modelling by the extended colloidal XDLVO theory (Extended Derjarguin-Landau-Verwey-Overbeek) for coagulation and gravel upflow filtration (GUF) and sand downflow rapid filtration (SDRF) to the technology of double filtration applied to study water containing Microcystis spp. The XDLVO theory has been shown to be efficient at evaluating the behavior of the colloidal particles as a function of the separation distance, making apparent how the intermolecular and surface forces act: acid-base interaction (AB), Lifshitz-Vander Walls (vdW), double electric layer (DEL) and Born repulsion forces. Such forces that act in this colloidal system formed by Microcystis spp. were analyzed in terms of their mutual interaction and their interaction with porous environments in double filtration at the stable thermodynamic situations (precoagulation) and at unstabilized by the chemical coagulation. The raw water energetic barrier of repulsion and after the sand downflow rapid filtration gave an average decreasing of about 90% in absolute values. • The application of mathematical models allows the study of complex environments. • The chemical coagulant acts on electrostatic destabilization, decreasing the absolute value of the electrical potential of the electrical double layer. • The XDLVO theory is efficient in studying the behavior of energies and interaction forces along the particle separation distance.
Acta Scientiarum. Technology, 2012
Models of the filtration phenomenon describe the mass balance in bed filtration in terms of parti... more Models of the filtration phenomenon describe the mass balance in bed filtration in terms of particle removal mechanisms, and allow for the determination of global particle removal efficiencies. These models are defined in terms of the geometry and characteristic elements of granule collectors, particles and fluid, and also the composition of the balance of forces that act in the particle collector system. This work analyzes particles collection efficiency comparing downflow and upflow direct filtration, taking into account the contribution of the gravitational factor of the settling removal efficiency in future proposal of initial collection efficiency models for upflow filtration. A qualitative analysis is also made of the proposal for the collection efficiency models for particle removal in direct downflow and upflow filtration using a Computational Fluid Dynamics (CFD) tool. This analysis showed a strong influence of gravitational factor in initial collection efficiency (t = 0) of particles, as well as the reasons of their values to be smaller for upflow filtration in comparison with the downflow filtration.
Análise De Modelo Matemático Monodisperso Para a Remoção De Partículas Na Filtração Utilizando Método De Levenberg-Marquardt
Mathematical modeling for models monodisperse suspensions removal constitutes a challenge in term... more Mathematical modeling for models monodisperse suspensions removal constitutes a challenge in terms of both complexity algorithmic and computational performance depending on the complexity of the interrelationships between the particles of various sizes and spatial configurations. The present work analyzes the efficiency of particle removal by comparing the direct up and down filtration, a mathematical model of monodisperse particle removal in filtration, using the method of Levenberg-Marquardt. Double filtration tests were used on a pilot scale, with data filtering up and quick filter descendant to the sensitivity analysis and calibration of models. Disparate results were obtained with the regression coefficient for multivariate equations (R2) of the order of 50% up to 99% of adherence to experimental data. These results indicate the feasibility of models and the need for further studies in the subject. Index Terms – flocculation, mathematical modelling, re-flocculation, aggregation...
Acta Scientiarum. Technology, 2015
Mathematical models of the filtration process are based on the mass balance in the filter bed. Mo... more Mathematical models of the filtration process are based on the mass balance in the filter bed. Models of the filtration phenomenon describe the mass balance in bed filtration in terms of particle removal mechanisms, and allow for the determination of global particle removal efficiencies. This phenomenon is defined in terms of the geometry and the characteristic elements of granule collectors, particles and fluid, and the composition of the balance of forces that act in the particle collector system. This type of resolution is well known as the trajectory analysis theory. Particle trajectory analysis by mathematical correlation of the dimensionless numbers that represent fluid and particle characteristics is considered the main approach for mathematically modeling the initial collection efficiency of particle removal in water filtration. The existing initial collection efficiency models are designed for downflow filtration. This study analyzes initial collection efficiency models, and proposes an adaptation of these models to direct upflow filtration in a granular bed of coarse sand and gravel, taking into account the contribution of the gravitational factor of the settling removal efficiency in the proposal of initial collection efficiency models.
Avaliação Sazonal Do Conforto Ambiental Térmico Em Espaços Públicos Abertos No Município De Umuarama-PR
Having the user as “figure” inserted in the environment, the importance of open public spaces whi... more Having the user as “figure” inserted in the environment, the importance of open public spaces while landscapes built gains haste with the world trend to promote the sustainability of these spaces. The focus is on environmental variables of comfort which is the fundamental premise for the permanence and the multiple uses of these open spaces of local cultural and social references. However, research is scarce relating to environmental agents. Thermal well-being in these spaces is of fundamental importance. In the city of Umuarama-PR there are currently thirty public squares, the squares will be addressed in this work representative located in Avenida Brazil, a major axis of the city which covers the squares Santos Dumont, John Paul VI and Plaza Brasilia. Will be presented an analysis of the seasonal evaluation in terms of measurements of the variables of luminous intensity and relative humidity at various points of the above mentioned squares. Keywords - squares, seasonal evaluation,...
Ambiente e Agua - An Interdisciplinary Journal of Applied Science, 2022
Environmental pollution is a worldwide concern, especially when caused by sewage dumping into wat... more Environmental pollution is a worldwide concern, especially when caused by sewage dumping into water bodies. Many substances are present in industrial or domestic wastewater, causing contamination in superficial water collection. Surfactants stand out for being widely used both industrially and domestically. The use of detergents and many types of surfactants was increased during the Covid-19 pandemic period, a fact observed in the levels in the effluent sample analysis from a Sewage Treatment Plant (STP) - Vila City around 21 and 39 mg L-1 in this period. This work evaluated the surfactant concentrations in the primary and secondary treatment units of the Vila City STP, in the city of Paranavaí-PR.-Brazil. In addition, the use of a post-treatment by slow sand filtration and adsorption by activated carbon produced from spent coffee grounds in the complementary removal of surfactants was proposed. A mixed bed with sand and activated carbon columns was made on a pilot scale, and filtr...
Brazilian Journal of Health Review, 2022
Avaliar a eficiência dos processos em uma Estação de Tratamento de Esgoto (ETE) é um instrumento ... more Avaliar a eficiência dos processos em uma Estação de Tratamento de Esgoto (ETE) é um instrumento fundamental na busca de uma sociedade mais sustentável. Este trabalho procurou avaliar parâmetros menos comuns, mas muito importantes para o equilíbrio sustentável do corpo hídrico receptor deste efluente, ainda que tratado: a DQO (demanda química de oxigênio), os surfactantes e os óleos e graxas. Foram avaliadas as concentrações destes parâmetros em diferentes etapas do processo de tratamento de esgoto da ETE Vila City, na cidade de Paranavaí-PR com o objetivo de se verificar a eficiência dos processos utilizados no tratamento do esgoto para adequação das concentrações destes aos valores referenciados pela legislação brasileira de lançamento de efluentes na coleção hídrica. Os valores obtidos para concentração destes parâmetros no período estudado indicam: remoção de cerca de 73% na concentração de DQO; remoção de cerca de 30% na concentração de óleos e graxas; média de remoção de cerca de menos de 8% na concentração de surfactantes. Palavras-chave: efluente, estação de tratamento de esgoto, sustentabilidade.
This paper proposes to present an application of CFD programs in a simulation of the flow in a hy... more This paper proposes to present an application of CFD programs in a simulation of the flow in a hydraulic jump. Initially, it has been introduced the nonlinear representative equations of the flow and the turbulence models necessary to solve Navier-Stokes equations. Therefore, it will be demonstrated how to resolve theses equations using the numerical methods by means of discretisetion and system solve. Finally, it will be shown a transient problem application in a simulation of a hydraulic jump of horizontal channel. The turbulence model used for proposed problem resolution was the Reynolds Stress Model (RSM), which better represents the physical flow characteristics of the problem. A comparison of the numerical results with experimental data has showed two different behaviors: the free surface in the experimental data presents the level of upstream agreement higher than in the hydraulic jump, therefore, in the first one the experimental data line was immerged in to 90% of volume fr...
31st Annual Frontiers in Education Conference. Impact on Engineering and Science Education. Conference Proceedings (Cat. No.01CH37193), 2001
In a Country like Brazil, more than ever it is necessary to increase the number of researchers, c... more In a Country like Brazil, more than ever it is necessary to increase the number of researchers, committed with environment principally because this Country has an immense challenge to defeat: to promote development for the welfare of people without forgetting the human aspects involved in the relations-man, progress and nature. So it is imperative the creation of alternatives for the qualification of scientific minds to make science and create technology. This project consists in a proposal of an Environmental Engineering Program, conceived by the Coordinating Team of Engineering School of Lusiada University Center. It is a five years program, having in its curriculum some new courses of modern sciences, besides the ones demanded by the Education Law of Brazil, for engineering programs. It is a modular education, developed in periods, called "theoretical modules" and "search modules". They last four months each and they are complimentary. At the end of the Program s/he will be an engineer capable to promote human welfare contributing to decrease the grade of the impact of progress over nature and even over men.
Engenharia Sanitaria e Ambiental, 2012
Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de fo... more Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de forças e balanço de energia de complexos coloidais na água bruta e daqueles formados durante a filtração direta em escoamento ascendente. Nele são descritos os perfis de energia de interação entre as superfícies dos colóides para três geometrias: esférica, plana e cilíndrica; e quatro arranjos de interação entre as superfícies: dois cilindros, dois planos, duas esferas e uma esfera e um plano. Duas situações foram analisadas, antes e após a desestabilização eletrostática pela ação de sulfato de alumínio em águas de estudo contendo caulinita, utilizando-se a modelação e análise pela teoria DLVO (das iniciais de Derjarguin-Landau-Verwey-Overbeek) modificada, ou XDLVO, que inclui à abordagem tradicional das forças da dupla camada elétrica (DCE), forças de atração de superfície ou London-van der Waals (LvdW), forças estéricas, força hidrofóbica e forças de outras origens no cálculo do balanço ...
Engenharia Sanitaria e Ambiental, 2012
Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de fo... more Este trabalho utilizou a teoria coloidal para descrever o comportamento físico pelo balanço de forças e balanço de energia de complexos coloidais na água bruta e daqueles formados durante a filtração direta em escoamento ascendente. Nele são descritos os perfis de energia de interação entre as superfícies dos colóides para três geometrias: esférica, plana e cilíndrica; e quatro arranjos de interação entre as superfícies: dois cilindros, dois planos, duas esferas e uma esfera e um plano. Duas situações foram analisadas, antes e após a desestabilização eletrostática pela ação de sulfato de alumínio em águas de estudo contendo caulinita, utilizando-se a modelação e análise pela teoria DLVO (das iniciais de Derjarguin-Landau-Verwey-Overbeek) modificada, ou XDLVO, que inclui à abordagem tradicional das forças da dupla camada elétrica (DCE), forças de atração de superfície ou London-van der Waals (LvdW), forças estéricas, força hidrofóbica e forças de outras origens no cálculo do balanço ...
Radiologia Brasileira, 2005
dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É... more dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É formado pelo decaimento radioativo do 226 Ra, um descendente do urânio (238 U), o qual é encontrado em quantidades variadas em solos, rochas e águas (2,3). O 222 Rn se desintegra por emissão de partícula alfa (T 1/2 = 3,82 dias), originando uma cadeia de decaimento conhecida como filhos ou descendentes do radônio. Por ser um gás, o radônio produzido no interior de rochas e solos difunde-se com facilidade através de fissuras, tubulações, buracos e lençóis freáticos até alcançar a superfície terrestre (4). Dessa forma, altas concentrações de 222 Rn podem ocorrer em ambientes fechados ou pouco ventilados e, assim, representar risco potencial à saúde
Modelação matemática macroscópica da perda de carga e da remoção de sólidos suspensos totais na filtração direta ascendente; Macroscopic mathematical …
Eng. sanit. ambient, 2007
Resumo: A utilização de um modelo matemático permite a obtenção de condições otimizadas de operaç... more Resumo: A utilização de um modelo matemático permite a obtenção de condições otimizadas de operação, o que conduz à melhoria do controle e da previsão do processo de filtração. Os modelos matemáticos descrevem o processo de filtração através dos ...
Radiologia Brasileira, 2005
dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É... more dioativo e responsável por aproximadamente metade desta dose de radiação de ocorrência natural. É formado pelo decaimento radioativo do 226 Ra, um descendente do urânio (238 U), o qual é encontrado em quantidades variadas em solos, rochas e águas (2,3). O 222 Rn se desintegra por emissão de partícula alfa (T 1/2 = 3,82 dias), originando uma cadeia de decaimento conhecida como filhos ou descendentes do radônio. Por ser um gás, o radônio produzido no interior de rochas e solos difunde-se com facilidade através de fissuras, tubulações, buracos e lençóis freáticos até alcançar a superfície terrestre (4). Dessa forma, altas concentrações de 222 Rn podem ocorrer em ambientes fechados ou pouco ventilados e, assim, representar risco potencial à saúde
Engenharia Sanitaria e Ambiental, 2005
A metodologia encontrada na literatura para a otimização do gradiente de velocidade médio em reat... more A metodologia encontrada na literatura para a otimização do gradiente de velocidade médio em reatores de mistura completa, com câmaras em série de escoamento contínuo, a partir de ensaios em reator estático tipo jarteste, baseia-se em modelos matemáticos que descrevem a cinética dos encontros entre partículas durante a floculação. Considerando-se que a aplicabilidade desta metodologia tem-se revelado inconsistente, como observado por diversos autores, este trabalho propõe uma metodologia racional para utilizar e otimizar os dados experimentais obtidos em reatores estáticos e, utilizando modelos matemáticos, obter dados para o projeto de floculadores mecanizados em série em estações de tratamento de água.