Simulação de fluxo de fluidos em meios porosos desordenados uma análise de efeito de escala na estimativa da permeabilidade e do coeficiente de arrasto

The present study provides a methodology that gives a predictive character the computer simulations based on detailed models of the geometry of a porous medium. We using the software FLUENT to investigate the flow of a viscous Newtonian fluid through a random fractal medium which simplifies a two-dimensional disordered porous medium representing a petroleum reservoir. This fractal model is formed by obstacles of various sizes, whose size distribution function follows a power law where exponent is defined as the fractal dimension of fractionation Dff of the model characterizing the process of fragmentation these obstacles. They are randomly disposed in a rectangular channel. The modeling process incorporates modern concepts, scaling laws, to analyze the influence of heterogeneity found in the fields of the porosity and of the permeability in such a way as to characterize the medium in terms of their fractal properties. This procedure allows numerically analyze the measurements of permeability k and the drag coefficient Cd proposed relationships, like power law, for these properties on various modeling schemes. The purpose of this research is to study the variability provided by these heterogeneities where the velocity field and other details of viscous fluid dynamics are obtained by solving numerically the continuity and Navier-Stokes equations at pore level and observe how the fractal dimension of fractionation of the model can affect their hydrodynamic properties. This study were considered two classes of models, models with constant porosity, MPC, and models with varying porosity, MPV. The results have allowed us to find numerical relationship between the permeability, drag coefficient and the fractal dimension of fractionation of the medium. Based on these numerical results we have proposed scaling relations and algebraic expressions involving the relevant parameters of the phenomenon. In this study analytical equations were determined for Dff depending on the geometrical parameters of the models. We also found a relation between the permeability and the drag coefficient which is inversely proportional to one another. As for the difference in behavior it is most striking in the classes of models MPV. That is, the fact that the porosity vary in these models is an additional factor that plays a significant role in flow analysis. Finally, the results proved satisfactory and consistent, which demonstrates the effectiveness of the referred methodology for all applications analyzed in this study.

Potencial larvicida de extratos de plantas regionais no controle de larvas de Aedes aegypti

Dengue, amongst the virus illnesses one can get by vectorial transmission, is the one that causes more impact in the morbidity and mortality of world s population. The resistance to the insecticides has caused difficulties to control of vector insect (Aedes aegypti) and has stimulated a search for vegetables with larvicidal activity. The biodiversity of Caatinga is barely known and it is potential of use even less. Some plants of this biome are commercialized in free fairs northeast of Brazil, because of its phytotherapics properties. The vegetables in this study had been selected by means of a questionnaire applied between grass salesmen and natives of the Serido region from Rio Grande do Norte state; culicids eggs had been acquired with traps and placed in container with water for the larva birth. Thirty larvae had been used in each group (a group control and five experimental groups), with four repetitions four times. The vegetables had been submitted to the processes of decoction, infusion and maceration in the standard concentration of 100g of the vegetable of study in 1l of H2O and analyzed after ½, 1, 2, 4, 8, 12, 24 and 48 hours for verification of the average lethal dose (LD50) from the groups with thirty larva. The LD50 was analyzed in different concentrations (50g/l, 100g/l, 150g/l, 200g/l e 300g/l) of Aspidosperma pyrifolium Mart. 48 extracts of rind, leaf and stem of the seven vegetal species: Aspidosperma pyrifolium Mart., Mimosa verrucosa Benth, Mimosa hostilis (Mart.) Benth., Myracrodruon urundeuva Allemão, Ximenia americana L, Bumelia sartorum Mart Zizyphus joazeiro Mart, had been analyzed. The extracts proceeding from the three methods were submitted to the freezedrying, to evaluate and to quantify substances extracted in each process. The results had shown that Aspidosperma pyrifolium Mart. and Myracrodruon urundeuva Allemão are the species that are more distinguished as larvicidal after 24 hours of experiment, in all used processes of extraction in the assays. The Zizyphus joazeiro Mart species has not shown larvicidal activity in none of the assays. In relation to the extraction method, the decoction was the most efficient method in the mortality tax of the A. aegypti larvae

Photoacoustics as a tool for the diagnosis of radicular stress: Measurements in eucalyptus seedlings

In reforesting companies (cellulose industry), eucalyptus is usually cultivated in small plastic containers (50 mL). As seedlings remain for about 120 days in these containers-until transplantation-their roots become space restricted, with consequent limitations in water and nutrient absorption. These restrictions may lead to plant stress, decreasing productivity. In this work, we used the photoacoustic technique to evaluate the photosynthetic activity of Eucalyptus grandis, E. urophylla and E. urograndis seedlings subjected to this limited space availability, seeking a correlation with morphological parameters and fluorescence measurements in these seedlings. Photoacoustic, fluorescence, and morphological analysis were conducted every 15 days, from 45 to 120 days after sowing. Fluorescence and photosynthetic rate were evaluated in vivo and in situ, the latter one using the open photoacoustic technique. Data show that root dry matter diminished markedly at 90 and 120 days after sowing; this behavior showed a high correlation with the gas exchange component of the photoacoustic signal, as well as with the fluorescence ratio Fv/Fm. These results indicate that the soil volume of the container becomes insufficient for the roots after 90 days, probably leading to a nutritional deficiency in plants, which explains the decrease observed in the photosynthetic rate of seedlings. (C) 2003 American Institute of Physics.

Estudo de pré-formulação para dose fixa combinada dos tuberculostáticos rifampicina, isoniazida, pirazinamida e etambutol (4 em 1)

According to the global framework regarding new cases of tuberculosis, Brazil appears at the 18th place. Thus, the Ministry of Health has defined this disease as a priority in the governmental policies. As a consequence, studies concerning treatment and prevention have increased. Fixed-dose combination formulations (FDC) are recognized as beneficial and are recommended by WHO, but they present instability and loss on rifampicin bioavailability. The main purpose of this work was to carry out a pre-formulation study with the schedule 1 tuberculosis treatment drugs: rifampicin, isoniazid, pyrazinamide and ethambutol and pharmaceutical excipients (lactose, cellulose, magnesium stearate and talc), in order to develop an FDC product (150 mg of rifampicin + 75 mg of isoniazid + 400 mg of pyrazinamide + 250 mg of ethambutol). The studies consisted of the determination of particle size and distribution (Ferret s diameter) and shape through optical microscopy, as well as rheological and technological properties (bulk and tapped densities, Hausner Factor, Carr s Index, repose angle and flux rate) and interactions among drugs and drug excipient through thermal analysis (DSC, DTA, TG and your derivate). The results showed that, except isoniazid, the other drugs presented poor rheological properties, determined by the physical characteristics of the particles: small size and rod like particles shape for rifampicin; rectangular shape for pyrazinamide and ethambutol, beyond its low density. The 4 drug mixture also not presented flowability, particularly that one containing drug quantity indicated for the formulation of FDC products. In this mixture, isoniazid, that has the best flowability, was added in a lower concentration. The addition of microcrystalline cellulose, magnesium stearate and talc to the drug mixtures improved flowability properties. In DSC analysis probable interactions among drugs were found, supporting the hypothesis of ethambutol and pyrazinamide catalysis of the rifampicin-isoniazid reaction resulting in 3- formylrifamycin isonicotinyl hydrazone (HYD) as a degradation product. In the mixtures containing lactose Supertab® DSC curves evidenced incompatibility among drugs and excipient. In the DSC curves of mixtures containing cellulose MC101®, magnesium stearate and talc, no alterations were observed comparing to the drug profiles. The TG/DTG of the binary and ternary mixtures curves showed different thermogravimetrics profiles relating that observed to the drug isolated, with the thermal decomposition early supporting the evidences of incompatibilities showed in the DSC and DTA curves

Variabilidade espacial de populações de Diatraea saccharalis em canaviais e sugestão de método de amostragem

A broca Diatraea saccharalis é uma das mais importantes pragas da cana-de-açúcar no Brasil. O manejo de áreas infestadas está embasado no controle biológico com Cotesia flavipes, cujas liberações são feitas em função da população de lagartas da praga em campo. Por esta razão, a estimativa desta população é de fundamental importância para o sucesso do programa de manejo. Assim, o objetivo do presente trabalho foi estudar a variabilidade espacial de D. saccharalis em canaviais e sugerir um método de amostragem que permitisse uma estimativa adequada das populações em campo. Seis campos de aproximadamente 1 ha cada um foram amostrados, em grid retangular de aproximadamente 10 x 10 m, com ilhas. Cada ponto de amostragem foi representado pela coleta das formas biológicas da praga no interior dos colmos em 2 m de sulco. Na maioria das áreas, as populações de formas imaturas de D. saccharalis distribuíram-se de forma contagiosa, com alcance do semivariograma variando de 18 a 80 m. Com base no alcance médio, estimou-se em seis o número médio de pontos de amostragem por hectare que deveriam ser feitos para representar adequadamente a área. Este número foi menor do que o estimado utilizando parâmetros da estatística clássica. Sugere-se que, para estimativa das formas imaturas de D. saccharalis em canaviais, a amostragem seja feita em grid de 40 x 40 m, o que resulta em aproximadamente seis pontos de amostragem por hectare e permitirá, na maioria das áreas, efetuar levantamentos com independência e coeficientes de variação menores que 50%.

O princípio constitucional da eficiência aplicado à outorga e à cobrança da água produzida na exploração petrolífera

Water production is unavoidable during a petrol well s lifetime. The amount of produced water associated with oil varies a lot. It can reach values which account to 50% in volume up to nearly 100%, at the end of the well s economic life. It could be verified that, once the water reaches the productive wells, there must be a management of this produced water. Its destiny is defined after a precise study, after which the best option is chosen between relieving it into the environment, re-injecting it into the producing container or disposing it into non-producing formations. Whichever option is made by the involved professionals, after the necessary analysis, it shall consider, besides the technical and economical aspects, also the alternatives which entail less environmental impact. The purpose of the present research is to conduct a study about the application of the constitutional principle of efficiency on the instruments worked out by the public administration on water management, specifically the water use licence and charging for the use in the management of water resources applicable to water production at the petrol wells. In this attempt, before entering the proper approach of the efficiency of the mentioned instruments, it was necessary not only bring to light the doctrinal perception about the constitutional principle of administrative efficiency, but also make some considerations concerning to the structure of the national water resources management, set by the Federal Constitution (1988) and the federal legislation (9433/97)

Perdas de grãos e distribuição de palha na colheita mecanizada de soja

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resistência e mecanismos envolvidos em genótipos de milho em relação ao ataque do gorgulho, Sitophilus zeamais Mots. (Coleoptera: Curculionidae)

A resistência de 30 genótipos de milho ao ataque de Sitophilus zeamais Mots. foi avaliada em teste sem chance de escolha, sendo efetuada uma seleção de 10 deles (M 9560, XHT 12, A 952, AG 5011, X 9557, Z 8452, C 615, C 435, DINA 888, C 606), os quais foram submetidos ao teste com chance de escolha, avaliando-se a atratividade e a preferência para oviposição. Pelos resultados concluiu-se que os genótipos menos atrativos foram Z 8452 (3,1%) e M 9560 (3,2%), enquanto o mais atrativo foi C 615 (24,7%). Os genótipos que apresentaram resistência do tipo não-preferência para oviposição foram A 952, M 9560 e XHT 12 com números médios de 2,0; 3,0 e 3,4 ovos por recipiente. A resistência do tipo não-preferência para alimentação e/ou antibiose foi observada nos genótipos M 9560, A 952 e Z 8452. Os genótipos com alta suscetibilidade ao gorgulho foram C 435, C 444, C 606 e AG 8010.

Desenvolvimento da cochonilha-branca planococcus citri (risso, 1813) (hemiptera: pseudococcidae) em frutíferas

The citrus mealybug, Planococcus citri is an important pest attacking several crops. Biotic and abiotic factors, as well as the substrate they feed on influence its population. The present study was aimed to study the effect of some feeding substrates on mealybug development in laboratory conditions. Leaf disks of guava, fig and cherimoya were placed individually on an agar film inside a Petri dish. One egg of the insect was confined inside each container, replicated 60 times for each treatment. Containers were kept in a climatized chamber at 25[degree] C, 70 [plus or minus] 10% RH and 12 hours photophase. Insects reared on guava leaves showed a longer nymphal development, while the female longevity was longer on fig leaves. However, no statistical differences were found in the survival index, which showed values higher than 83%, suggesting that all substrates studied here were adequate for the development of P. citri.

Effect of Diets on Biology of Abaris basistriata and Selenophorus seriatoporus (Coleoptera: Carabidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reflexões sobre a construção e evolução de conceitos geométricos nas séries intermediárias do ensino fundamental

This thesis represents a didactic research linked to the Post-graduation Programme in Education of the Universidade Federal do Rio Grande do Norte which aimed to approach the construction of the geometrical concepts of Volume of the Rectangular Parallelepiped, Area and Perimeter of the Rectangle adding a study of the Area of the Circle. The research was developed along with students from the 6th level of the Elementary School, in a public school in Natal/RN. The pedagogical intervention was made up of three moments: application of a diagnostic evaluation, instrument that enabled the creation of the teaching module by showing the level of the geometry knowledge of the students; introduction of a Teaching Module by Activities aiming to propose a reflexive didactic routing directed to the conceptual construction because we believed that such an approach would favor the consolidation of the learning process by becoming significant to the apprentice, and the accomplishment of a Final Evaluation through which we established a comparison of the results obtained before and after the teaching intervention. The data gathered were analyzed qualitatively by means of a study of understanding categories of mathematical concepts, in addition to using descriptive statistics under the quantitative aspect. Based on the theory of Richard Skemp, about categorization of mathematical knowledge, in the levels of Relational and Instrumental Understanding were achieved in contextual situations and varied proportions, thus enabling a contribution in the learning of the geometrical concepts studied along with the students who took part in the research. We believe that this work may contribute with reflections about the learning processes, a concern which remained during all the stages of the research, and also that the technical competence along with the knowledge about the constructivist theory will condition the implementation of a new dynamics to the teaching and learning processes. We hope that the present research work may add some contribution to the teaching practice in the context of the teaching of Mathematics for the intermediate levels of the Elementary School

Morphological description of Amblyomma brasiliense Aragão, 1908 (Acari: Ixodidae) larvae and nymphs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Armazenamento e requerimento fotoblástico de sementes de Acacia polyphylla DC

Acacia polyphyla (Mimosaceae) é uma espécie arbórea nativa do Brasil, importante para a recuperação de áreas degradadas. Sementes dessa espécie foram armazenadas em condições naturais e artificiais, com os objetivos de avaliar a longevidade das sementes no solo, conservar a sua qualidade fisiológica pelo período correspondente a duas colheitas e verificar o requerimento fotoblástico das sementes armazenadas. em condições naturais, as sementes foram enterradas em clareira, sob dossel ralo e sob dossel denso. As sementes deterioraram rapidamente, revelando-se incapazes de compor o banco de sementes do solo. em condições artificiais, as sementes foram acondicionadas em diferentes embalagens e armazenadas por dois anos em ambiente não controlado e em câmara fria. Periodicamente, as sementes foram colocadas para germinar a 25ºC, na ausência de luz e sob fotoperíodo de oito horas sob luzes branca e de sombreamento. Durante todo o período de armazenamento, a germinação no escuro foi inferior à constatada sob luzes branca e de sombreamento. A qualidade fisiológica foi conservada por dois anos, quando as sementes foram acondicionadas em embalagem impermeável e armazenadas em câmara fria. O comportamento germinativo das sementes armazenadas por dois anos foi comparado com o de sementes recém-colhidas, em temperaturas constante e alternada, não sendo constatado efeito da idade e do regime de temperatura no requerimento fotoblástico das sementes.

Minimally processed guava fruits (Psidium guajava L.)

'Paluma' guavas, after internal quality evaluation using magnetic resonance tomography, were used to produce fresh-cut product. Fruits were peeled or not, cut in halves and seed removed, and they were packaged in polystyrene trays covered with PVC film or in a PET container with a lid. These packages were stored for 12 days at 5 degrees C, 10 degrees C and ambient temperature (22.6 degrees C). Tomography evaluation verified that impacts produced internal bruising with loss of cellular integrity and liquefication of the placenta tissues. Compression was more evident on the pericarp and cutting promoted superficial deformation. Storage temperature affected the weight loss, with fruit packaged in the polystyrene tray having a greater weight loss. The peeling did not influence weight loss. Product stored at 5 degrees C and 10 degrees C for 8 days had low microbial growth (< 10(3) UFC.g(-1)) and no coliforms. Rapid spoilage and a short shelf life (3-4 days) occurred when the product was stored at ambient temperature. Peeling reduced ascorbic acid concentration and total soluble solids. Use of calcium to protect fresh-cut products was not efficient. Calcium absorption capacity of 'Pedro Sato' guava was tested using Ca-45. Fruits treated with 2% CaCl2, with or without the radioisotope, were divided in four layers (epicarp, mesocarp, endocarp and seed) and analyzed for the total and Ca-45 calcium. It was observed that the applied calcium remained in superficial layers of fruits, which was confirmed by autoradiography. Internal layers did not contain Ca-45, indicating that calcium was not distributed into different parts of the fruit.

Método simples e acessível para determinar amônia liberada pela cama aviária

A amônia é um gás altamente irritante e causador de estresse às aves confinadas, o que leva à perda de peso, podendo até causar a morte. Por esse motivo, existe grande interesse em se determinar a quantidade de amônia liberada por diferentes camas aviárias e de diferentes condições, bem como os fatores que influenciam a produção desta substância. Assim, idealizou-se o presente trabalho com o objetivo de desenvolver e padronizar uma metodologia simples, acessível, exeqüível para avaliar camas de frangos submetidas a diferentes condições (diferentes tratamentos, tempos de confinamento e temperatura) e capaz de determinar a potencialidade da liberação de amônia pela cama de frangos nos galpões. A metodologia baseou-se na adaptação do método da microdifusão, que consta da incubação da cama em um frasco de vidro com capacidade de 500 mL. Sobre a superfície do material incubado coloca-se um béquer de 50 mL contendo 10 mL de solução de ácido bórico 2% (m/v) para fixar a amônia exalada pela cama aviária. Esse sistema é fechado e incubado por 15 horas a 30°C e, após, a solução fixadora é retirada e titulada com ácido sulfúrico 0,05 N, usando como indicador uma mistura de verde de bromocresol e alaranjado de metila. O método proposto apresenta precisão para ser usado em experimentos e utiliza material barato e reagentes facilmente encontrados nos laboratórios.