1,720,965 research outputs found
Stabilization for a degenerate wave equation with drift and potential term with boundary fractional derivative control
Full text linkThis paper explores the boundary stabilization of a degenerate wave equation in the nondivergence form, which includes a drift term and a singular potential term. Additionally, we introduce boundary fractional derivative damping at the endpoint where divergence is absent. Using semi-group theory and the multiplier method, we establish polynomial stability, with a decay rate depending upon the order of the fractional derivative
STABILITY OF DEGENERATE WAVE EQUATIONS WITH A SINGULAR POTENTIAL AND LOCAL DAMPING
No full textIn this paper, we investigate the stability of a degenerate/singular wave equation featuring localized singular damping, along with a drift term and a leading operator in non-divergence form. We establish exponential stability results in this context under suitable conditions on the degeneracy and singularity coefficients
Asymptotic Behavior of a transmission Heat/Piezoelectric smart material with internal fractional dissipation law
No full textIn this paper, we analyze the stability of a system involving a heat-conducting copper rod and a magnetizable piezoelectric beam, where fractional damping influences the longitudinal displacement of the beam's centerline. The coupled dynamics are governed by partial differential equations that incorporate heat diffusion in the copper rod and piezoelectric effects in the beam, including both mechanical and electrical interactions. Previous research has extensively studied piezoelectric systems and heat transfer dynamics separately, but the combined effect with fractional damping presents a novel challenge. Our investigation employs semi-group theory and multiplier methods to establish a polynomial stability result that is dependent on the order of the fractional derivative, offering insights into the interplay between heat transfer and piezoelectric behavior under fractional damping, which is critical for developing robust and efficient energy harvesting devices and structural control mechanisms
Energy decay of some boundary coupled systems involving wave\ Euler-Bernoulli beam with one locally singular fractional Kelvin-Voigt damping
No full textIn this paper, we investigate the energy decay of hyperbolic systems of wave-wave, wave-Euler-Bernoulli beam and beam-beam types. The two equations are coupled through boundary connection with only one localized non-smooth fractional Kelvin-Voigt damping. First, we reformulate each system into an augmented model and using a general criteria of Arendt-Batty, we prove that our models are strongly stable. Next, by using frequency domain approach, combined with multiplier technique and some interpolation inequalities, we establish different types of polynomial energy decay rate which depends on the order of the fractional derivative and the type of the damped equation in the system
STABILITY FOR DEGENERATE WAVE EQUATIONS WITH DRIFT UNDER SIMULTANEOUS DEGENERATE DAMPING
Full text linkIn this paper we study the stability of two different problems. The first one is a one-dimensional degenerate wave equation with degenerate damping, incorporating a drift term and a leading operator in non-divergence form. In the second problem we consider a system that couples degenerate and non-degenerate wave equations, connected through transmission, and subject to a single dissipation law at the boundary of the non-degenerate equation. In both scenarios, we derive exponential stability results
The energy decay rate of a transmission system governed by the degenerate wave equation with drift and under heat conduction with the memory effect
Full text linkIn this paper, we investigate the stabilization of the transmission problem of the degenerate wave equation and the heat equation under the Coleman-Gurtin heat conduction law or Gurtin-Pipkin law with the memory effect. We investigate the polynomial stability of this system when employing the Coleman-Gurtin heat conduction, establishing a decay rate of type t-4t<^>{-4}. Next, we demonstrate exponential stability in the case when Gurtin-Pipkin heat conduction is applied
Stability Results of an Elastic/Viscoelastic Transmission Problem of Locally Coupled Waves with Non Smooth Coefficients
No full textInternational audienceWe investigate the stabilization of a locally coupled wave equations with only one internal viscoelastic damping of Kelvin-Voigt type (see System (1.2)-(1.4)). The main novelty in this paper is that both the damping and the coupling coefficients are non smooth (see (1.5)). First, using a general criteria of Arendt-Batty, combined with an uniqueness result, we prove that our system is strongly stable. Next, using a spectrum approach, we prove the non-exponential (uniform) stability of the system. Finally, using a frequency domain approach, combined with a piecewise multiplier technique and the construction of a new multiplier satisfying some ordinary differential equations, we show that the energy of smooth solutions of the system decays polynomially of type t −1
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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