1,721,310 research outputs found
Environmental Impact of Organic Farming on Water in Friuli Venezia Giulia Region (NE Italy)
No full textThe effects of Vadasz term, anisotropy and rotation on bi-disperse convection
No full textThe onset of thermal convection in a uniformly rotating and horizontally isotropic bi-disperse porous medium, taking into account the Vadasz term, is investigated. Via linear instability analysis, it has been proved that the Vadasz term allows the onset of convection via an oscillatory state but does not affect convection via a stationary motion
Well-posedness of slightly compressible Boussinesq’s flow in Darcy–Bénard problem
No full textIn the present article, we show the existence, uniqueness, and behavior in time of solutions to the Darcy–Bénard
problem for an extended-quasi-thermal-incompressible fluid (extended Darcy–Bénard problem) uniformly heated from below,
modeling the phenomenon of thermal convection in porous media. First and foremost, for the sake of a more realistic
description of the phenomenon under analysis, we here assume the fluid’s density to depend on pressure and temperature,
unlike the classical problem where the density is solely a function of temperature. This new constitutive law for the density,
proposed by Guoin and Ruggeri in 2012, arises as a necessary requirement for the thermodynamic consistency of the model
and introduces a slight compressibility making the model more closely aligned with reality. Moreover, the dependence of
the fluid density on both temperature and pressure fields, from the mathematical viewpoint, adds an interesting challenge,
requiring a new approach for its resolution. The well-posedness results establish a foundation for further analyses of the
hydrodynamic stability properties of the solutions of the extended Darcy–Bénard problem, with particular regard to the
effect of compressibility factor, which has great interest in applications
Onset of convection in LTNE Darcy–Brinkman anisotropic porous layer: Cattaneo effect in the solid
No full textThe onset of convection in anisotropic porous medium in local thermal non-equilibrium regime is studied. The Cattaneo's law to describe heat propagation in solid phase is allowed, while the Fourier's law in fluid phase is employed. Linear and nonlinear stability of the conduction solution are performed and the critical Rayleigh numbers in a closed form are obtained. The influence of second sound effect, inter-phase heat transfer and anisotropy of the medium on the onset of instability have been analysed via numerical simulations, too
Refinement of pain evaluation techniques. The formalin test
No full textThe formalin test is an important means of assessing pain evoked-behaviours induced by moderately intense and long-lasting noxious stimuli, yet the procedures for performing the test have not been standardised, hindering comparisons of data. In rodents, the level of sensitivity to the test and the evoked response have been observed to change depending on a number of variables. Among them, gender is the most important, although many other variables can influence the behavioural response (e.g., the animal species, the strain of mice and rats, housing conditions, and early social experience). In the present work, we provide information on the procedures used to perform the formalin test and the effects of both these procedures and the conditions and manipulation prior to the test on the animal and its behaviour, with the ultimate goal of improving these procedures and conditions and decreasing the variability among laboratories
Soret phenomenon in porous Magneto-Hydrodynamics
No full textThe onset of double-diffusive convection in horizontal porous layers filled by an electrically conducting fluid embedded in a magnetic field, is investigated on taking into account of Soret phenomenon. Sufficient conditions guaranteeing the onset of steady or oscillatory convection in a closed algebraic form are obtained. Conditions guaranteeing that Hopf convection in the absence of Soret phenomenon, turns into steady convection by the Soret parameter, have been found
Thermal convection for a Darcy-Brinkman rotating anisotropic porous layer in local thermal non-equilibrium
No full textThe onset of natural convection in a fluid-saturated anisotropic porous layer, which rotates about the vertical axis, under the hypothesis of local thermal non-equilibrium, is analysed. Since the porosity of the medium is assumed to be high, the more suitable Darcy-Brinkman model is adopted. Linear instability analysis of the conduction solution is carried out. Nonlinear stability with respect to L2-norm is performed in order to prove the coincidence between the linear instability and the global nonlinear stability thresholds. The effect of both rotation and thermal and mechanical anisotropies on the critical Rayleigh number for the onset of instability is discussed
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