Numerical study of nonlinear heat transfer from a wavy surface to a high permeability medium with pseudo-spectral and smoothed particle methods

Motivated by petro-chemical geological systems, we consider the natural convection boundary layer flow from a vertical isothermal wavy surface adjacent to a saturated non-Darcian high permeability porous medium. High permeability is considered to represent geologically sparsely packed porous media. Both Darcian drag and Forchheimer inertial drag terms are included in the velocity boundary layer equation. A high permeability medium is considered. We employ a sinusoidal relation for the wavy surface. Using a set of transformations, the momentum and heat conservation equations are converted from an (x, y) coordinate system to an (x,η) dimensionless system. The two-point boundary value problem is then solved numerically with a pseudo-spectral method based on combining the Bellman–Kalaba quasi linearization method with the Chebyschev spectral collocation technique (SQLM). The SQLM computations are demonstrated to achieve excellent correlation with smoothed particle hydrodynamic (SPH) Lagrangian solutions. We study the effect of Darcy number (Da), Forchheimer number (Fs), amplitude wavelength (A) and Prandtl number (Pr) on the velocity and temperature distributions in the regime. Local Nusselt number is also computed for selected cases. The study finds important applications in petroleum engineering and also energy systems exploiting porous media and undulating (wavy) surface geometry. The SQLM algorithm is shown to be exceptionally robust and achieves fast convergence and excellent accuracy in nonlinear heat transfer simulations

Oat–buckwheat breads – technological quality, staling and sensory properties

peer reviewedThe technological and sensory properties and the staling of breads made from oat flour (OF) and buckwheat flour (BF) were analysed. Significant differences in protein and ash content were found in the experimental breads due to significant differences in the composition of the BF and OF used. As the proportion of BF in the recipe increased, a deterioration in the technological properties of the dough and bread as well as an increase in the crumb hardness were observed. The presence of OF in the recipe increased the bread volume, significantly enhanced the lightness of the crust and crumb and improved the overall sensory quality. The OF used in the recipe decreased the starch retrogradation enthalpy value, which is strongly related to a delay in bread staling. The proposed bakery products can be attractive to consumers who are looking for new food products

Effect of habitat and landscape structure on waterbird abundance in wetlands of central Argentina

Determining the response of birds to local habitat characteristics and landscape structure is essential to understanding habitat selection and its consequences for the distribution of species. This study identified the influence of environmental factors as determinants of the waterbird assemblage composition in 39 wetlands in the Pampas of central Argentina. Multivariate analysis allowed the identification of environmental factors affecting the use of habitat by waterbird species, whose variable numbers were explained by local and landscape environmental factors. Interspecific variation in responses to changes in environmental factors shows that habitat selection occurs at a species-specific level, although species with similar ecological requirements tend to respond similarly to environmental heterogeneity. Plovers and flamingos were mostly associated with high salinity and the presence of a muddy shoreline and temporary ponds; ducks, herons and ibises were associated with vegetation abundance and decrease in salinity; piscivores and carnivorous species were associated with water depth. The small degree of overlap of habitat requirements between some species suggests a high level of specialization within waterbird assemblages. This knowledge can be used for the design of appropriate conservation and management strategies in central Argentina, where the alarming loss of wetlands requires management strategies that ensure the permanence of the greatest diversity of waterbirds.Fil: Brandolin, Pablo Germán. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Biología Agrícola. Cátedra de Botanica Sistematica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Blendinger, Pedro Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Investigaciones Ecológicas de las Yungas; Argentin