483 research outputs found

    On the prediction of shear-layer flows with rans and SRS models

    Get PDF
    This study evaluates the ability of Reynolds-Averaged Navier-Stokes (RANS) and Scale-Resolving Simulations (SRS) models to predict turbulent shear-layer predominant (blunt- body) flows. The selected cases are the flows around a circular cylinder at Re = 3, 900 and 140, 000, and past a rounded square prism at Re = 100, 000 and incidence angles of 0 and 45 degrees. These cases exhibit complex features making numerical predictions a challenge, in particular, for turbulence modelling: shear-layers (free, boundary and wake), laminar-turbulent transition, low to moderate Reynolds numbers, flow separation and unsteadiness. In this pa- per, the aforementioned cases are simulated employing isotropic and anisotropic RANS, De- layed Detached-Eddy Simulation (DDES), eXtra Large-Eddy Simulation (XLES), and Partially- Averaged Navier-Stokes (PANS) equations. The outcome confirms that traditional isotropic RANS are unable to accurately predict such flows, whereas SRS models can significantly reduce modelling errors. Furthermore, the results show that anisotropic RANS models are an inter- esting engineering option owing to its compromise between accuracy and cost. Nonetheless, an improvement of the modelling accuracy by both anisotropic RANS and SRS models is inevitably coupled with an increase of the numerical demands

    Bone fragility in postmenopausa women: a preliminar study

    Get PDF
    The aim of this work is to identify the prevalence of risks factors for bone fragility in postmenopausal women with hormonal replacement therapy (HRT) within two groups (with bone fracture history and without bone fracture history) and to evaluate the effect of modifiable risk factors on bone mineral density (BMD). The overall prevalence of osteoporosis in postmenopausal Portuguese women is high. A pattern identification of occurrences, in a group of patients submitted to this analysis, will enable the formulation of conclusions for knowledge improving of these different pathologies. This preliminary study will demonstrate that age, physical exercise and coffee consumption are associated with lower BMD and osteoporosis status in postmenopausal Portuguese woman

    Incorporating oldman saltbush hay and prickly pear in diets for red Sindhi calves

    Get PDF
    This study was designed to evaluate the nutrient intake, digestibility, degradability, and ruminal characteristics of Sindhi heifers fed diets that contained a combined total of 75% oldman saltbush hay (hereafter saltbush hay) and prickly pear cactus. Eight 12-month old intact male red Sindhi calves (four fistulated and four non-fistulated) with an initial mean weight of 170 ± 5 kg were assigned to 4 × 4 Latin squares, where factors consisted of four diets, namely 15% hay and 60% cactus; 30% hay and 45% cactus; 45% hay and 30% cactus; and 60% hay and 15% cactus, and four times at which rumen fluid was collected. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) intakes in kg/day and NDF in percentage live weight (LW), water intake, salinity, and conductivity increased with hay level. Intake and digestibility of non-fibrous carbohydrates were curvilinear with higher values in diets containing 30% saltbush hay. The apparent digestibility of dry matter (DM) and organic matter decreased linearly as the concentration of saltbush hay increased in the diet. The pH of the rumen fluid was within the acceptable range for favourable microbial growth. The low temperature and high salinity and conductivity indices in the diets should be viewed with caution at higher concentrations of saltbush hay, because of a possible decrease in nutrient absorption and the development of health problems in the animals. Apparent degradability coefficients of DM and NDF were affected significantly by inclusion of prickly pear and saltbush hay in the diets.Keywords: animal nutrition, apparent digestibility, Atriplex nummularia Lindl, Opuntia ficus, ruminal degradation, semi-arid environmen

    Tailoring Bi2MoO6 by Eu3+ incorporation for enhanced photoluminescence emissions

    Get PDF
    Here, an experimental study is presented on the structural, electronic, and optical properties of Bi2-xMoO6:xEu3+ (x = 0, 0.5, 1.0, 2.0, and 4.0 mol%) materials, synthesized by means of the microwave-assisted solvothermal method using ethylene glycol as a solvent. Different characterization techniques (X-ray diffraction measurements with Rietveld refinements, Raman and ultraviolet–visible diffuse reflectance spectroscopy, field emission scanning electron microscopy, and photoluminescence emissions) have been employed to examine the structural and electronic properties, energy transfer and defect evolution which control the performance of the as-synthetized materials. Present findings provide deep insights into the substitution of Eu3+ cations in Bi2MoO6, with focus on their influence on process that dictate the superior optical properties.Funding for open access charge: CRUE-Universitat Jaume

    Dutch disease-cum-financialization booms and external balance cycles in developing countries

    Get PDF
    We formally investigate the medium-to-long-run dynamics emerging out of a Dutch disease-cum-financialization phenomenon. We take inspiration from the most recent Colombian development pattern. The “pure” Dutch disease first causes deindustrialization by permanently appreciating the economy’s exchange rate in the long run. Financialization, i.e. booming capital inflows taking place in a climate of natural resource-led financial over-optimism, causes medium-run exchange rate volatility and macroeconomic instability. This jeopardizes manufacturing development even further by raising macroeconomic uncertainty. We advise the adoption of capital controls and a developmentalist monetary policy to tackle these two distinct but often intertwined phenomena
    • …
    corecore