EVALUATION OF PRESSURE DROP IN FLOW OVER FIXED POROUS BED

Many studies are conducted about the dynamics of fluids in porous media, which generates a number of factors and problems are solved. In particular the phenomenon of pressure drop in flows on fixed bed, although fairly well in the form Ergun’s equation, still has certain inconsistencies with regard to the types of materials to be used in the packaging of the beds. The objective of this work is to study this phenomenon using some experiments reported in the literature to determine the pressure drop in fixed bed consisting of porous particles of açaí seed. Experimental studies were conducted to predict, and take into account the losses resulting from friction and inertia that showed strong dependence on velocity. The method of using the particular friction factor prediction as a way to replace the usual calculation and measurement of pressure drop. The analysis in the wind tunnel was made from different sizes of bed, with a decrease in arithmetic progressions corresponding to half the value of the diameter of the tube used in the test. Several bands of Reynolds number were also employed in order to be able to visualize how the phenomenon behaves on various tracks. For such a survey was necessary some parameters such as açaí seeds diameters, seed weight and volume occupied by the bed; these parameters are of vital importance in Ergun equation, because an important aspect of the phenomenon is the porosity which enters as a foundation in the theory of flow fixed bed. At the end of the study was found the divergence in big bands of the Reynolds number of the correlation between experimental data and the Ergun equation

Severe hyperchloremic metabolic acidosis with SGLT2 inhibitors in patients with urinary diversion

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Conditional stability of unstable viscous shock waves in compressible gas dynamics and MHD

Extending our previous work in the strictly parabolic case, we show that a linearly unstable Lax-type viscous shock solution of a general quasilinear hyperbolic--parabolic system of conservation laws possesses a translation-invariant center stable manifold within which it is nonlinearly orbitally stable with respect to small $L^1\cap H^3$ perturbations, converging time-asymptotically to a translate of the unperturbed wave. That is, for a shock with $p$ unstable eigenvalues, we establish conditional stability on a codimension-$p$ manifold of initial data, with sharp rates of decay in all $L^p$. For $p=0$, we recover the result of unconditional stability obtained by Mascia and Zumbrun. The main new difficulty in the hyperbolic--parabolic case is to construct an invariant manifold in the absence of parabolic smoothing.Comment: 32p

Metodologia de extração de proteínas em torta de mamona e pinhão manso para análise por eletroforese (SDS-PAGE).

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Avaliação de espécies florestais e pastagens em sistemas silvipastoris em Paragominas, Pará, Brasil.

Propor modelos alternativos de uso-da-terra, econômicos e ecologicamente sustentáveis, tem sido um grande desafio da pesquisa agrícola na Amazônia. Os sistemas silvipastoris têm sido considerados promissores para integrar o cultivo arbóreo na pecuária e recuperar extensas áreas de pastagens degradadas da Amazônia. Entretanto, ainda carecem de uma base científica que suporte sua recomendação mais ampla. Em Paragominas-PA, foram estudados nove sistemas silvipastoris, de um hectare cada, constituídos da combinação binária de três espécies florestais (Schizolobium amazonicum, Bagassa guianensis e Eucalyptus terenticornis), plantadas em faixas de 6 m e afastadas de 12 m, com três pastagens (Brachiaria brizantha cv. Marandu, Brachiaria humidicola e Panicum maximum cv. Colonião/Brachiaria dictyoneura). Novilhos pastaram as parcelas experimentais simulando um sistema rotativo, com 14 dias de permanência e 42 dias de descanso. Foram medidos a altura e o diâmetro à altura do peito das espécies florestais, a massa de forragem e a proteína bruta das pastagens. Os componentes silvipastoris de melhor desempenho foram o Schizolobium amazonicum e Brachiaria brizantha cv Marandu. Dos pontos de vista florestal e pastoril, a combinação silvipastoril mais promissora foi Schizolobium amazonicum - Brachiaria brizantha cv Marandu

Petrographical and geochemical signatures of the Granja paragneisses (NW Ceará, Brasil)

The Granja Granulitic Complex (GCC) constitutes a NE–SW trending high-grade metamorphic belt occupying the western sector of the Médio Coreaú Domain (NW Ceará, Brasil) (Figs. 1 and 2). According to the published data, the GCC represents a segment of the Paleoproterozoic basement intensely reworked during the Brasiliano Orogeny. Lithologically, the GCC is mainly composed of garnet-sillimanite migmatitic paragneisses, enclosing discontinuous lenses of mafic granulites and enderbites. At outcrop scale, the GCC gneisses are well-foliated fineto medium-grained grey rocks showing a stromatic layering parallel to the main regional fabric (Fig. 3). The occurrence of lenses of leucocratic quartzfeldspathic material interlayered with the host paragneisses indicates that these rocks reached partial melting conditions during the Brasiliano orogenic event (≈ 600 Ma). Petrographically, the gneisses are characterized by the presence of mineral assemblages dominated by garnet, sillimanite and biotite with moderate amounts of quartz, plagioclase, cordierite and K-feldspar (Figs. 4a-b). Twelve whole-rock samples were analyzed for major and trace elements. As shown in Graph 1, all the analyzed samples plot in the sedimentary field. Their REE patterns closely resemble those of PAAS (PostArchean average Australian Shale) confirming the sedimentary origin of the paragneiss protoliths (Graph 2). Geochemical data also suggest that these sediments derived from source areas of felsic to intermediate composition and were deposited in a tectonically active continental margin (Graphs 3 and 4)

Manejo de plantas daninhas na cultura da mamoneira.

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