1,721,038 research outputs found
Phase-diagram of the Frustrated Gauge-invariant Ising-model
No full textThe phase diagram of the Z (2) gauge-invariant Ising model is studied at negative gauge coupling in three dimensions. Exact procedures are applied to establish the ground states and find, at nonzero temperatures, the minima of the local mean-field free energy. The resulting phase diagram exhibits one unfrustrated and two frustrated phases, in good agreement with Monte Carlo results. The interpretation of the various phases in terms of a gas of random surfaces with free edges is also discussed
Crumpled and Flat Regimes In A Random Surface Model
No full textA spherical like model of a D-dimensional random surface embedded in d-dimensional Euclidean space is studied in detail. The embedding weight depends on an attractive term between the nearest neighbours and on a repulsive one between some of the next to the nearest neighbours of the network. The repulsive term mimics an extrinsic curvature energy for surface configurations. Crumpled and flat regimes are found, and, if D less-than-or-equal-to 2, only the former survives in the thermodynamic limit. The model can be seen as the d --> infinity limit of a more realistic model where the 1/d corrections stabilize the flat regime in the thermodynamic limit at least for D = 2
Two-scale competition in phase separation with shear
No full textThe behavior of a phase separating binary mixture in uniform shear flow is investigated by numerical simulations and in a renormalization group approach. Results show the simultaneous existence of domains of two characteristic scales. Stretching and cooperative ruptures of the network produce a rich interplay where the recurrent prevalence of thick and thin domains determines log-time periodic oscillations. A power-law growth R(t) similar to t(alpha) of the average domain size, with alpha = 4/3 and alpha = 1/3 in the flow and shear direction, respectively, is shown to be obeyed
The segregation of sheared bynary fluids in the Bray-Humayun model
No full textThe phase separation process which follows a sudden quench
inside the coexistence region is considered for a binary
fluid subjected to an applied shear flow.
This issue is studied in the framework of the convection-diffusion equation
based on a Ginzburg-Landau free energy functional in the
approximation scheme introduced by
Bray and Humayun [Phys. Rev. Lett. 68, 1559 (1992)].
After an early stage where domains form and shear effects become
effective the system enters a scaling regime where the typical domains
sizes ,
along the flow and perpendicular to it
grow as and . The structure factor is characterized
by the existence of four peaks, similarly to previous theoretical
and experimental observations, and by exponential tails at large wavevectors
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
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
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