1,721,002 research outputs found
Mathematical and Physical Properties of an Extended Thermodynamics Multi-temperature Model for the Description of Gas Mixtures
No full textIn this paper, we analyze some mathematical and physical properties of a 13-moment extended thermodynamics model for gas mixtures with the multi-temperature assumption and Maxwellian productions. Starting from the 1960s, this model was derived independently by many authors and it was applied to different physical problems. Here, we verify the validity of the Shizuta-Kawashima condition and others mathematical properties. Moreover, we describe the stationary heat transfer and the acceleration waves predicted by these equations
On stationary heat conduction in 3D symmetric domains - an application of extended thermodynamics
No full textIn this paper, we study some three-dimensional stationary heat conduction problems in rarefied gases at rest, using the linearized 13-moment equations of extended thermodynamics. It follows that, in this linear theory, the temperature is still described by the Fourier law of heat conduction, while in contrast with the
Navier–Stokes law, the stress tensor does not vanish. Furthermore, a non-equilibrium temperature is introduced and differences between this temperature and the kinetic one are predicted
An extended thermodynamics description of stationary heat transfer in binary gas mixtures confined in radial symmetric bounded domains
No full textIn this paper, we describe the stationary heat transfer problem in non-reacting gas mixtures confined between two coaxial cylinders or two concentric spheres kept at different temperatures. For the description of this phenomenon, we refer to the extended thermodynamics 13-moments single temperature system and we compare its predictions with those obtained by the classical Navier–Stokes–Fourier–Fick approximations.
In contrast with the classical theory, we show that extended thermodynamics takes over also thermodiffusion
effects, predicts boundary layers for the common temperature and non-vanishing stress tensors. Furthermore, we compare the results with those already obtained in the planar case, in order to point out the effects of the radial dependence
Heat transfer in gas mixtures: Advantages of an extended thermodynamics approach
No full textIn this work we analyze and compare different approaches to the heat transfer problem in gas mixtures. Our aim is to show that for rarefied gases far from equilibrium the extended thermodynamics description is capable to reproduce some features observed by kinetic theory, that cannot be described by the Navier–Stokes–Fourier–Fick approximations. In this framework, we consider the case of a binary inert gas mixture confined between two infinite parallel plates kept at different temperatures
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Una formulazione del Metodo delle Strisce Finite per l’analisi di elementi in cemento armato. Parte I. Formulazione
No full textHeat transfer in a binary gas mixture between two parallel plates: an application of linear extended thermodynamics
No full textIn this paper, we present a heat transfer problem in a binary inert mixture of ideal gases at rest between two parallel plates. For the description of the phenomenon, we have considered the field equations of a linearized extended thermodynamics theory with 13 moments, under the assumption of a common temperature
for both the constituents. The solution of the system of equations presents non-controllable boundary values, for which a fluctuation principle is applied. We found that, unlike classical thermodynamics, the 13-moment field equations predict thermal diffusion effects and exhibit solutions with boundary layers. Moreover, the results are qualitatively similar to those obtained from the kinetic theory
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Some 2D heat transfer problems in metals described by a linearized extended thermodynamics model
Full text linkWe describe qualitatively some 2D stationary problems for metal electrons in the
presence of a temperature gradient and a magnetic field. To this aim we refer to a linearized
Extended Thermodynamics model that allows a semianalytical construction of the solutions.
The results are in agreement with the thermomagnetic effects already known in the literatu
- …
