Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The implantation system with rised beds and the use of surface irrigation can be important practices to increase efficiency of the drainage process and ensure the proper establishment of culture in the system of rotation, as well as ensuring the expression of the productive potential of maize in irrigated rice areas. In this way, the objectives of this study were: to assess the response of maize grown in irrigated rice areas as agronomic characteristics, yield components and grain yield under different deployment systems and surface irrigation; and evaluate the efficiency of water use by the culture of maize for the irrigated area treatments in different implantation systems. To reach the objectives, two field experiments were conducted during the crop 2014/15 in experimental systematized area of irrigated rice at the Universidade Federal de Santa Maria-RS. The experiment I, consisted of a factorial, conducted in random blocks design with four replications. The factor levels were composed by deployment systems: A1 = with rised beds; A2 = without rised beds; and factor D levels consisting of: D1 = with irrigation; D2 = without irrigation. Already the experiment II was conducted in random blocks design with two treatments: T1 = Irrigation by furrows; T2 = Witness (without irrigation), both in rised beds, with four replicates. Hybrid maize seeds were used AG9045 in both experiments. The results obtained show that use of the implantation system with rised beds provides an increase in agronomic characteristics of growth and maize yield components as well as increased efficiency of water use and increase in grain yield compared to the system without rised beds. The use of irrigation in periods of drought increases the maize yield in irrigated rice areas, regardless of the implantation system used. The combination of the implantation system with rised beds and furrow irrigation provides greater increase in maize yield, compared to the tested systems. / O sistema de implantação com camalhão e a utilização da irrigação por superfície podem ser práticas importantes para aumentar a eficiência do processo de drenagem e garantir o estabelecimento adequado da cultura no sistema de rotação, além de assegurar a expressão do potencial produtivo do milho em áreas de arroz irrigado. Nesse sentido, os objetivos do presente trabalho foram: avaliar a resposta do milho cultivado em áreas de arroz irrigado quanto às características agronômicas, componentes de rendimento e rendimento de grãos, sob diferentes sistemas de implantação e irrigação por superfície; e avaliar a eficiência de uso da água pela cultura do milho para os tratamentos irrigados por superfície nos diferentes sistemas de implantação. Para o atendimento dos objetivos, dois experimentos de campo foram conduzidos durante a safra 2014/15 em área experimental sistematizada de arroz irrigado da Universidade Federal de Santa Maria - RS. O experimento I, constituiu-se de um fatorial, conduzido em delineamento de blocos ao acaso com quatro repetições. Os níveis para o fator A foram compostos pelos sistemas de implantação: A1= com camalhão; A2= sem camalhão; e os níveis do fator D compostos por: D1= com irrigação; D2= sem irrigação. Já o experimento II foi conduzido em delineamento de blocos ao acaso com dois tratamentos: T1 = Irrigação por sulcos; T2 = Testemunha (sem irrigação), ambos sobre camalhões, com quatro repetições. Foram utilizadas sementes do milho híbrido AG9045 em ambos os experimentos. Os resultados obtidos evidenciam que a utilização do sistema de implantação com camalhão proporciona aumento em características agronômicas de crescimento e em componentes de rendimento do milho, além de maior eficiência do uso da água e acréscimo no rendimento de grãos, comparativamente ao sistema sem camalhão. O uso da irrigação em períodos de déficit hídrico no solo aumenta o rendimento de grãos de milho cultivado em áreas de arroz irrigado, independente do sistema de implantação utilizado. A combinação entre o sistema de implantação com camalhão e a irrigação é a que proporciona maior acréscimo no rendimento de grãos de milho, em relação aos sistemas testados.

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Pela primeira vez incêndios florestais são identificados em uma associação de fácies contendo a Flora Dicroidium nos sedimentos avermelhados do Triássico Médio (Ladiniano) na parte sul da Bacia do Paraná (Formação Santa Maria, Rio Grande do Sul). A extensão geográfica dessa assembleia de plantas foi, assim, estendida no Gondwana brasileiro. As análises por petrografia orgânica, fluorescência, microscopia eletrônica de varredura (MEV) e microscopia eletrônica de varredura (tipo field emission gun - MEV-FEG) revelaram a presença recorrente de carvão vegetal (charcoal) na sucessão vertical de fácies relacionadas a um modelo deposicional de fluxos efêmeros de baixa densidade do tipo inunditos. O carvão microscópico (micro-charcoal) ocorre como fragmentos comuns em diferentes fácies, enquanto que o carvão vegetal macroscópico (macro-charcoal) é representado por espécimes tridimensionais de lenhos atribuídos a gimnospermas (Pinaceae?) e por fragmentos achatados, finos e alongados atribuídos a pteridospermas (rachises de Dicroidium?) Os valores médios de reflectância da inertinita entre 2,80-6,61 %Ro medidos nos fragmentos de macro-charcoal evidenciaram processos de queima de alta temperatura, envolvendo tanto incêndios na copa quanto na interface copa-superfície. A recorrência de fragmentos queimados em várias fácies do perfil estudado indica a ocorrência de incêndios regionais que afetaram tanto as comunidades meso-xerófilas distais quanto às associações proximais higro- mesófilas, compostas majoritariamente por espécimes da Flora Dicroidium. A integração dos resultados obtidos a partir das múltiplas análises dos fragmentos de charcoal é consistente com um teor de oxigênio atmosférico superior a 20%. / For the first time wildfires are reported from an association of different facies containing a Dicroidium flora from the Middle Triassic (Ladinian) red beds in the southern part of the Paraná Basin (Santa Maria Formation, Rio Grande do Sul state). The geographical extension of the Dicroidium plant assemblage has thus been extended in the Brazilian Gondwana. Analyses through petrography, fluorescence microscopy, scanning (SEM) and field emission gun scanning electron microscopy (FEG-SEM) revealed recurrent charcoal presence in a vertical facies succession of depositional cycles related to ephemeral prograding low density flows. Microscopic charcoal occurs as common fragments within different facies whereas macroscopic charcoal is represented by tridimensional wood specimens assigned to gymnosperms (Pinaceae?) and by flattened, thin, elongated remains assigned to pteridospermophytes (rachises of Dicroidium?). Average reflectance values between 2.80-6.61 %Ro measured in the macro-charcoals evidenced burning processes of high temperature, involving fires both in the crown and in the crown-surface interface. The recurrence of charcoal in several facies of the studied profile indicates regional wildfires, which affected hinterland, meso-xerophyllous coniferous assemblages and marginal hygro-mesophyllous Dicroidium-like assemblages. The integration of results obtained from the multiple charcoal analyses is consistent with atmospheric oxygen content higher than 20%.

A população idosa está em crescimento no Brasil segundo dados do último Censo Demográfico do Instituto Brasileiro de Geografia e Estatística - IBGE. Com esta perspectiva é importante atentar-se para o fato de que durante o processo de envelhecimento ocorrem diversas mudanças físicas e psíquicas que influenciam a pessoa no uso dos espaços e dos produtos. Dentre esses produtos, a cama é extremamente necessária durante toda a vida e a sua utilização faz parte da rotina diária, sendo alta a ocorrência de quedas de idosos no uso deste produto. Embora as lesões e as quedas na utilização das camas não estejam diretamente associadas à terceira idade, neste período da vida, elas podem representar um problema de saúde mais grave. A intenção desta dissertação é a proposição de diretrizes projetuais para que as camas sejam seguras e confortáveis para os idosos. Para alcançar este objetivo e compreender as necessidades dos idosos desenvolveramse duas etapas distintas: a fundamentação teórica e a pesquisa de campo. Na fundamentação teórica, foram levantados os assuntos relevantes a oito temas principais: idosos, mercado de camas e colchões, segurança, conforto, desenho universal, ergonomia, antropometria e usabilidade, com a finalidade de apontar direcionamentos de projeto indicados pelos autores. A pesquisa de campo, realizada em uma instituição de longa permanência e dezenove residências, totalizando cinquenta idosos, contou com o método de estudo de casos múltiplos através da aplicação de entrevistas semi-estruturadas entre idosos e profissionais. A aplicação deste método auxiliou a elaboração das diretrizes, pois, além de identificar as dificuldades encontradas pelos idosos na utilização da cama, permitiu a identificação dos elementos que são mais importantes e os que necessitam de melhoria na opinião dos usuários. As entrevistas com os profissionais que lidam com idosos diariamente também auxiliou neste processo. Assim, a partir da sistematização dos dados obtidos na fundamentação teórica e na pesquisa de campo, são apresentadas diretrizes projetuais que visam a segurança e ao conforto do idoso, que possui a sua autonomia preservada, na utilização da cama. / The old population is growing in Brazil according to last data from Demographic Census of Instituto Brasileiro de Geografia e Estatística - IBGE. Based on this it is important to pay attention to the fact that during the aging process many physical and psychic changes happen which influence the person in the usage of spaces and products. Among these products the bed is extremely necessary during the whole life and its use is part of the daily routine, being high the incidence of falls of old people using this product. And although injuries and falls using beds are not directly related to the old population, during this period they can represent a grave health problem. The objective of this research is to propose project guidelines aiming that beds become safer and more comfortable for the old people. In order to reach this objective and understand the necessities of the old people two specific stages were established: the theoretical base and the field survey. In the theoretical base were raised issues related to eight main subjects: old people, the market of beds and mattresses, safety, comfort, universal design, ergonomics, anthropometry and usability, aiming to raise project guidelines indicated by the authors. The field survey, carried out in a long term stay institution and nineteen homes, totalizing fifty old people, counted with the multiple cases study method through the application of semi-structures interviews to old people and professionals. The application of this method helped the creation of the guidelines, since, besides identifying the difficulties found by the old people using the bed, allowed the identification of the most important elements and the ones which need enhancements in the users’ opinions. The interviews with the professionals which deal daily with old people also helped in this process. Because of this, based on the systematization of the data obtained in the theoretical base and in the field survey, project guidelines are presented aiming the safety and the comfort of the old people, who keep their autonomy preserved using the bed.

A população idosa está em crescimento no Brasil segundo dados do último Censo Demográfico do Instituto Brasileiro de Geografia e Estatística - IBGE. Com esta perspectiva é importante atentar-se para o fato de que durante o processo de envelhecimento ocorrem diversas mudanças físicas e psíquicas que influenciam a pessoa no uso dos espaços e dos produtos. Dentre esses produtos, a cama é extremamente necessária durante toda a vida e a sua utilização faz parte da rotina diária, sendo alta a ocorrência de quedas de idosos no uso deste produto. Embora as lesões e as quedas na utilização das camas não estejam diretamente associadas à terceira idade, neste período da vida, elas podem representar um problema de saúde mais grave. A intenção desta dissertação é a proposição de diretrizes projetuais para que as camas sejam seguras e confortáveis para os idosos. Para alcançar este objetivo e compreender as necessidades dos idosos desenvolveramse duas etapas distintas: a fundamentação teórica e a pesquisa de campo. Na fundamentação teórica, foram levantados os assuntos relevantes a oito temas principais: idosos, mercado de camas e colchões, segurança, conforto, desenho universal, ergonomia, antropometria e usabilidade, com a finalidade de apontar direcionamentos de projeto indicados pelos autores. A pesquisa de campo, realizada em uma instituição de longa permanência e dezenove residências, totalizando cinquenta idosos, contou com o método de estudo de casos múltiplos através da aplicação de entrevistas semi-estruturadas entre idosos e profissionais. A aplicação deste método auxiliou a elaboração das diretrizes, pois, além de identificar as dificuldades encontradas pelos idosos na utilização da cama, permitiu a identificação dos elementos que são mais importantes e os que necessitam de melhoria na opinião dos usuários. As entrevistas com os profissionais que lidam com idosos diariamente também auxiliou neste processo. Assim, a partir da sistematização dos dados obtidos na fundamentação teórica e na pesquisa de campo, são apresentadas diretrizes projetuais que visam a segurança e ao conforto do idoso, que possui a sua autonomia preservada, na utilização da cama. / The old population is growing in Brazil according to last data from Demographic Census of Instituto Brasileiro de Geografia e Estatística - IBGE. Based on this it is important to pay attention to the fact that during the aging process many physical and psychic changes happen which influence the person in the usage of spaces and products. Among these products the bed is extremely necessary during the whole life and its use is part of the daily routine, being high the incidence of falls of old people using this product. And although injuries and falls using beds are not directly related to the old population, during this period they can represent a grave health problem. The objective of this research is to propose project guidelines aiming that beds become safer and more comfortable for the old people. In order to reach this objective and understand the necessities of the old people two specific stages were established: the theoretical base and the field survey. In the theoretical base were raised issues related to eight main subjects: old people, the market of beds and mattresses, safety, comfort, universal design, ergonomics, anthropometry and usability, aiming to raise project guidelines indicated by the authors. The field survey, carried out in a long term stay institution and nineteen homes, totalizing fifty old people, counted with the multiple cases study method through the application of semi-structures interviews to old people and professionals. The application of this method helped the creation of the guidelines, since, besides identifying the difficulties found by the old people using the bed, allowed the identification of the most important elements and the ones which need enhancements in the users’ opinions. The interviews with the professionals which deal daily with old people also helped in this process. Because of this, based on the systematization of the data obtained in the theoretical base and in the field survey, project guidelines are presented aiming the safety and the comfort of the old people, who keep their autonomy preserved using the bed.

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Le travail réalisé porte sur la modélisation à l'échelle macroscopique des transferts thermiques dans les lits catalytiques et au voisinage de la paroi. L'objectif principal de ce travail est de comprendre et de modéliser les mécanismes physiques responsables des transferts thermiques dans cette région. La physique proche paroi est capturée à l'échelle macroscopique de façon univoque à l'aide du concept de changement d'échelle et la notion de prise de moyenne volumique est étendue aux types de systèmes que nous considérons. Le coefficient de transfert à la paroi du modèle à deux coefficients λr - hw est premièrement décortiqué afin de mettre en lumière les mécanismes physiques contenus dans cette notion ainsi que le poids de leur contribution respective. Un modèle, basé sur la dynamique de l'écoulement et décrivant le transport de la chaleur dans la direction radiale, est ensuite dérivé à l'échelle macroscopique. Il met notamment en évidence une zone proche paroi particulière, dominée par l'effet de canalisation, qui amortit les transferts diffusifs dans la direction normale à la paroi. On montre ainsi que les transferts thermiques pilotés essentiellement par des mécanismes de dispersion mécanique sont limités dans cette région par des effets de résistance thermique de type convective. Finalement, une loi de paroi décrivant une couche limite perturbée par la matrice solide est utilisée pour faire le raccord à la paroi, ce qui a permis de prédire avec satisfaction la température à la paroi. / This work deals with the modeling of near wall heat transfers in catalytic packed beds at the macroscopic scale. The main aims of the present work are the understanding and the modeling of physical mechanisms responsible for the heat transfers in the vicinity of the wall at the observation scale. Volume averaging concept is first extended to systems we consider. Thus, relevant physical mechanisms occurring in the near wall zone are unequivocally up-scaled from pore to bed scale. Then, the detailed analysis of the wall heat transfer coefficient, used in the popular two coefficient model λr - hw, brings to light each physical mechanism and its respective weighted contribution lumped in it. A model, based on the flow dynamic and describing the radial heat transfer, is finally derived at the reactor scale. It highlights that a channel effect occurs in the near wall zone, damping transfers by diffusion in the wall normal direction. It is hence showed that heat transfers mainly driven by mechanical dispersion are facing a convective thermal resistance near the wall. A wall law is also derived to model boundary layer/porous medium interactions, which ultimately connect the porous media model to the wall. Wall temperature is thus recovered with satisfaction.

Fluidized beds have widespread industrial applications ranging from chemical industries to power plants. The flow inside a fluidized bed system consists of two main phases, a particle phase and the fluid phase. The two phases are strongly coupled to each other through various forces like drag and pressure. Capturing this multiphase phenomenon requires modeling strategies that possess good fidelity over a range of scales. Discrete Element Modeling (DEM) coupled with Computational Fluid Dynamics (CFD) provides a good platform to analyze the complex coupled multiphase hydrodynamics inside fluidized bed systems. Conventional DEM-CFD framework suffers from contradictory spatial resolution requirements for the particle and fluid phases, respectively. This prevents the conventional DEM-CFD method to be applied to geometries that have features comparable to the particle diameter of the solid phase. The novelty of this work lies in the development and validation of a two-grid formulation that removes the resolution restrictions of the conventional DEM-CFD framework. The results obtained from this new framework agree reasonably well with the experiments showing the capability of the new scheme to simulate conditions not possible with conventional DEM-CFD framework. In addition, this research also focuses on performing both 2D and 3D jetting fluidized bed simulations having millions of particles; validate/compare results with experiments and to perform heat transfer studies in a jetting fluidized bed system. The results suggest convective and diffusive mixing for a single jet at higher superficial velocity to be better than the mixing obtained in a multiple jet framework. The comparison with experimental results obtained in a multiple jetting setup shows that a 2D simulation captures the essential jet characteristics near the distributor plate reasonably well while a 3D simulation is needed to capture proper bubble dynamics near the freeboard of the bed. These results give insight into the detailed dynamics of fluidized bed systems and provide a foundation for a better design of these systems. / Ph. D.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The increased necessity to obtain power from other sources than conventional fossil fuels has led to the growing interest in solar power. The problem with the proposed technology is that it can only provide power during the day and therefore requires some sort of storage system, if power is to be supplied throughout the day and night. A number of storage systems exist, but the one of particular interest for this research, is packed rock beds. Rock beds have the advantage that if designed right, they have the potential to be one of the most cost effective means of storing thermal energy for solar power plants. Discrete Element Models (DEM) of rock beds were therefore developed through both experimental and numerical procedures, by conducting a series of sensitivity, calibration and verification studies. The developed models were then used to study various aspects associated with rock beds, which were either too impractical, impossible or too expensive to conduct through actual experimental work. This research focused specifically on the potential of constructing self-supporting tunnels within the rock beds in order to improve the air flow uniformity through the bed, while minimizing the pressure drop. It was observed that if the appropriate steps were followed, stable self-supporting tunnels could be formed. Valuable information such as the rock orientations resulting from different packing directions could also be derived from the models and finally, a method to convert the DEM models into the appropriate format such that it could be imported into a CFD preprocessor for future CFD studies, was developed. / AFRIKAANSE OPSOMMING: Die verhoogde noodsaaklikheid om energie te verkry uit ander bronne as konvensionele fossielbrandstowwe, het gelei tot die groeiende belangstelling in sonkrag energie. Die probleem met die voorgestelde tegnologie is dat dit net energie gedurende die dag kan voorsien en dus word daar ’n stoorstelsel benodig indien energie deur beide die dag en nag voorsien moet word. Tans bestaan daar wel ’n aantal van hierdie stoorstelsels, maar die een wat van besondere belang is in hierdie navorsing, is verpakte klip beddens. Klip beddens het die voordeel dat, indien dit reg ontwerp is, dit oor die potensiaal beskik om een van die mees koste-doeltreffende middels te wees vir die stoor van termiese energie vir sonkragstasies. Diskreet Element Modelle (DEM) van die klip beddens is ontwikkel deur gebruik te maak van beide experimentele en numeriese metodes waartydens ’n reeks sensitiwiteits-, kalibrasie- en verifiëring studies uitgevoer is. Die ontwikkelde modelle is gebruik om verskeie aspekte van klip beddens te ondersoek, wat of te onprakties, onmoontlik of te duur is vanuit ’n eksperimentele oogpunt. Hierdie navorsing het spesifiek gefokus op die potensiaal om self-ondersteunende tonnels binne in die klip beddens te vorm, ten einde die egaligheid van die lugvloei deur die bed te verbeter, terwyl die drukval geminimeer word. Daar is waargeneem dat stabiele self-ondersteunende tonnels wel gevorm kon word indien die toepaslike stappe gevolg is. Waardevolle inligting soos die klip oriëntasies wat as gevolg van die verskillende verpakkings rigtings onstaan kon ook vanuit die model verkry word. Ten slotte is ’n metode ontwikkel om die DEM modelle na die toepaslike formaat te omskep sodat dit ten einde gebruik kan word in numeriese vloeidinamika studies.

This study addressed the numerical modelling of flow and diffusion in packed beds of mono-sized spheres. Comprehensive research was conducted in order to implement various numerical approaches in explicit1 and implicit2 simulations of flow through packed beds of uniform spheres. It was noted from literature that the characterization of a packed bed using porosity as the only geometrical parameter is inadequate (Van Antwerpen, 2009) and is still under much deliberation due to the lack of understanding of different flow phenomena through packed beds. Explicit simulations are not only able to give insight into this lack of understanding in fluid mechanics, but can also be used to develop different flow correlations that can be implemented in implicit type simulations. The investigation into the modelling approach using STAR-CCM+®, presented a sound modelling methodology, capable of producing accurate numerical results. A new contact treatment was developed in this study that is able to model all the aspects of the contact geometry without compromising the computational resources. This study also showed, for the first time, that the LES (large eddy simulation) turbulence model was the only model capable of accurately predicting the pressure drop for low Reynolds numbers in the transition regime. The adopted modelling approach was partly validated in an extensive mesh independency test that showed an excellent agreement between the simulation and the KTA (1981) and Eisfeld and Schnitzlein (2001) correlations' predicted pressure drop values, deviating by between 0.54% and 3.45% respectively. This study also showed that explicit simulations are able to accurately model enhanced diffusion due to turbulent mixing, through packed beds. In the tortuosity study it was found that the tortuosity calculations were independent of the Reynolds number, and that the newly developed tortuosity tests were in good agreement with techniques used by Kim en Chen (2006), deviating by between 2.65% and 0.64%. The results from the TMD (thermal mixing degree) tests showed that there appears to be no explicit link between the porosity and mixing abilities of the packed beds tested, but this could be attributed to relatively small bed sizes used and the positioning and size of the warm inlet. A multi-velocity test showed that the TMD criterion is also independent of the Reynolds number. It was concluded that the results from the TMD tests indicated that more elaborate packed beds were needed to derive applicable conclusions from these type of mixing tests. The explicit BETS (braiding effect test section) simulation results confirmed the seemingly irregular temperature trends that were observed in the experimental data, deviating by between 5.44% and 2.29%. From the detail computational fluid dynamics (CFD) results it was possible to attribute these irregularities to the positioning of the thermocouples in high temperature gradient areas. The validation results obtained in the effective thermal conductivity study were in good agreement with the results of Kgame (2011) when the same fitting techniques were used, deviating by 5.1%. The results also showed that this fitting technique is highly sensitive for values of the square of the Pearson product moment correlation coefficient (RSQ) parameter and that the exclusion of the symmetry planes improved the RSQ results. It was concluded that the introduction of the new combined coefficient (CC) parameter is more suited for this type of fitting technique than using only the RSQ parameter. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012