Planar Contraction
Mostrando 1-8 de 8 artigos, teses e dissertações.
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1. Study of rheological properties of polypropylenes in shear and elongational flows. / Estudo das propriedades reológicas de polipropilenos em fluxos de cisalhamento e fluxos elongacionais.
In this work, experimental methods to evaluate elongational and shear viscosities using a planar channel with an abrupt contraction (also called Cogwell die) were developed. The shear viscosity measurements were compared to measurements obtained using a rotational rheometer and a capillary rheometer. The elongational die was used to evaluate the influence of
Publicado em: 2007
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2. Extension of GENSMAC to incompressible flows governed by the Maxwell and K-BKZ integral models / Extensão de GENSMAC para escoamentos de fluidos governados pelos modelos integrais Maxwell e K-BKZ
Este trabalho tem como objetivo desenvolver um método numérico para simular escoamentos incompressíveis, isotérmicos, confinados ou com superfícies livres, de fuidos viscoelásticos governados pelos modelos integrais de Maxwell e K-BKZ (Kaye-Bernstein, Kearsley e Zapas). A técnica numérica apresentada é uma extensão do método GENSMAC (Tomé McKee -
Publicado em: 2006
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3. Microscopic spiral waves reveal positive feedback in subcellular calcium signaling.
The regenerative Ca(2+)-induced Ca2+ release mechanism is an important amplifier of signal transduction in diverse cells. In heart muscle cells, this mechanism contributes to the Ca2+ transient activating the mechanical contraction, but it is also believed to drive Ca2+ waves propagating within the cytosol. We investigated the subcellular Ca2+ distribution i
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4. Giant-block twist grain boundary smectic phases
Study of a diverse set of chiral smectic materials, each of which has twist grain boundary (TGB) phases over a broad temperature range and exhibits grid patterns in the Grandjean textures of the TGB helix, shows that these features arise from a common structure: “giant” smectic blocks of planar layers of thickness lb > 200 nm terminated by GBs that are s
National Academy of Sciences.
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5. Histamine modulates contraction and cyclic nucleotides in cultured rat mesangial cells. Differential effects mediated by histamine H1 and H2 receptors.
Histamine influences the glomerular microcirculation and modulates immune-inflammatory responses. In the rat kidney, histamine is synthesized by glomeruli and stimulates cyclic nucleotide production specifically in glomeruli. We investigated the in vitro effect of histamine on cyclic nucleotide accumulation in rat cultured glomerular mesangial and epithelial
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6. Changes in pennation with joint angle and muscle torque: in vivo measurements in human brachialis muscle.
1. Estimates of pennation in human muscles are usually obtained from cadavers. In this study, pennation of human brachialis was measured in vivo using sonography. Effects of static and dynamic changes in elbow angle and torque were investigated. 2. Pennation was measured in eight subjects using an 80 mm, 5 MHz, linear-array ultrasound transducer to generate
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7. A tethered adhesive particle model of two-dimensional elasticity and its application to the erythrocyte membrane.
A new model of two-dimensional elasticity with application to the erythrocyte membrane is proposed. The system consists of a planar array of self-adhesive particles attached to nearest neighbors with flexible tethers. Stretching from the equilibrium dimension is resisted because force is required to dissociate the particle clusters and to decrease the distri
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8. Functional calcium release channel formed by the carboxyl-terminal portion of ryanodine receptor.
The ryanodine receptor (RyR) is one of the key proteins involved in excitation-contraction (E-C) coupling in skeletal muscle, where it functions as a Ca2+ release channel in the sarcoplasmic reticulum (SR) membrane. RyR consists of a single polypeptide of approximately 560 kDa normally arranged in a homotetrameric structure, which contains a carboxyl (C)-ter