1,721,083 research outputs found
Two relaxation times and thermal nonlinear waves along wires with lateral heat exchange
Full text linkWe propose a model for studying several nonlinear waves for heat transport along a cylindrical system with lateral non-linear heat transfer to the environment. We consider relaxational equations, each with its own relaxation time, for longitudinal heat transfer and for lateral heat transfer across the wall. We consider two kinds of nonlinear lateral heat transport: radiative heat transport, and flux-limited heat transport. This work generalizes our previous studies in which the relaxation time for the lateral heat transfer was considered equal to that of the longitudinal heat flux. We explore the influence of both relaxation times on the propagation speed of linear and nonlinear waves, and on the form of nonlinear waves
Guidelines per la promozione dell’innovazione nel sistema giudiziario italiano
No full textNonostante nel linguaggio di tutti i giorni siano utilizzati spesso come sinonimi, “cambiamento” e “innovazione” sono due processi organizzativi distinti. Come si evince dalla letteratura su questi temi (Daft 1978; Damanpour and Evan 1984; Damanpour 1996; Catino 2012), infatti, un’organizzazione cambia quando vengono introdotte idee o comportamenti già esistenti, mentre innova nel momento in cui vengono superati l’ordine vigente e le convinzioni radicate nel corso del tempo. Innovare, dal latino novare, significa abbattere la tradizione, la sfera del “si è sempre fatto così”, per esplorare nuovi percorsi e modi di agire fino ad ora sconosciuti
Maria Adeida Raschini, La dialettica dell' intégralità. Studi sul pensiero del Michèle Federico Sciacca (M. A. Raschini, Scritti, 4), 1985
No full textBarbotin Edmond. Maria Adeida Raschini, La dialettica dell' intégralità. Studi sul pensiero del Michèle Federico Sciacca (M. A. Raschini, Scritti, 4), 1985. In: Revue des Sciences Religieuses, tome 61, fascicule 1-2, 1987. p. 99
Nonlinear Thermal Transport with Inertia in Thin Wires: Thermal Fronts and Steady States
Full text linkIn a series of papers we have obtained results for nonlinear heat transport when thin wires exchange heat non-linearly with the surroundings, with particular attention to propagating solitons. Here we obtain and discuss new results related to the propagation of nonlinear heat fronts and some conceptual aspects referring to the application of the second principle of thermodynamics to some nonlinear steady states related to non-propagating solitons
A power-law model for nonlinear phonon hydrodynamics
No full textThe Guyer-Krumhansl equation for the heat flux is a phenomenological bridge between Fourier heat transport (for size of the system much bigger than the mean free path of heat carriers) and hydrodynamic heat transport (for size of the system comparable to the mean free path of heat carriers). The corresponding phonon hydrodynamics is analogous to Newtonian hydrodynamics, but with the velocity replaced by the heat flux, the pressure gradient replaced by the temperature gradient and the shear viscosity replaced by the square of the mean-free path divided by the thermal conductivity. In this paper, we propose a nonlinear generalization of the Guyer-Krumhansl equation and phonon hydrodynamics based on an analogy with the power-law model of non-Newtonian fluids leading to a non-diffusive behaviour of heat transport. On the basis of this model, we obtain the corresponding nonlinear effective thermal conductivity of the model, depending on the radius of the channel and on the temperature gradient. The present proposal could be useful in the light of recent analyses of Poiseuille phonon hydrodynamics which suggest a non-Newtonian behaviour
Maria Adeida Raschini, La dialettica dell' intégralità. Studi sul pensiero del Michèle Federico Sciacca (M. A. Raschini, Scritti, 4), 1985
No full textBarbotin Edmond. Maria Adeida Raschini, La dialettica dell' intégralità. Studi sul pensiero del Michèle Federico Sciacca (M. A. Raschini, Scritti, 4), 1985. In: Revue des Sciences Religieuses, tome 61, fascicule 1-2, 1987. p. 99
A Mathematical Analysis of the Intermediate Behaviour of the Energy Cascades of Quantum Turbulence
Full text linkWe propose a mathematical interpolation between several regimes of energy cascade in quantum turbulence in He II. On the basis of a physical interpretation of such mathematical expression we discuss in which conditions it is expected to appear an intermediate k(2) regime (equipartition regime) in the transition region between the hydrodynamic regime and the Kelvin wave regime (namely, between the k(-5/3) and k(-1) regions in coflow situations and between the k(-3) and k(-1) regions in counterflow situations). It is seen that if the energy rate transfer from the hydrodynamic region to the Kelvin wave region is sufficiently slow, such equipartition region will be present, but for higher values of such energy rate transfer it will disappear. For high rates of the energy rate transfer, the transition regime between the hydrodynamic and the Kelvin wave regimes will be monotonous, characterized by a negative exponent of k between -5/3 and -1 (or between -3 and -1), instead of the positive 2 exponent of the equipartition regime
The wall effect in a plane counterflow channel
No full textIn this paper, we study the influence of the boundary conditions of the velocity fields in superfluid helium counterflow experiments. To make progress, we perform numerical simulations where we allow a slip velocity of the viscous component at the walls, and observe how this impacts on velocity fields and density profiles of distribution of quantized vortices. We conclude that the presence of a slip velocity at the walls generates a more homogeneous vortex distribution throughout the channel
Nonlinear Guyer–Krumhansl equation and its boundary conditions in nanolayers
Full text linkThis paper deals with nonlinear effects in the Guyer-Krumhansl equation for nonlocal heat transport, both from the perspective of the boundary conditions (phonon-wall collisions) and of the bulk equation (phonon-phonon collisions) and explores their consequences on the effective thermal conductivity of nanosystems between two parallel layers or in two-dimensional ribbons. The nonlinearity arises from a dependence of the respective mean free paths on the values of the heat flux. The boundary conditions refer to slip heat flow along the limiting walls of the system, analogous to velocity slip flow along the walls in rarefied fluid dynamics. The effective thermal conductivity turns out to depend on the Knudsen numbers related to both mean free paths and on the temperature gradient
Al servizio dell’(auto) governo dell’organizzazione giudiziaria. Nascita ed evoluzione della Struttura Tecnica per l’Organizzazione
No full textGli studi organizzativi insegnano che per comprendere nel dettaglio il funzionamento di un organismo occorre oltrepassare il livello prescrittivo delle norme e delle procedure che formalmente ne governano l’azione. Le strutture organizzative, infatti, raramente nascono e si sviluppano in maniera lineare, ma spesso evolvono e si affermano seguendo traiettorie complesse, a volte imprevedibili. Sulla base di tale consapevolezza, questo saggio si propone di ricostruire e commentare il percorso che ha portato alla nascita e al progressivo sviluppo della Struttura Tecnica per l’Organizzazione (S.T.O.), staff che svolge funzioni di supporto permanente alla VII Commissione del Consiglio Superiore della Magistratura
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