1,721,440 research outputs found
A Continuous Dependence Result for a Dynamic Debonding Model in Dimension One
No full textIn this paper we address the problem of continuous dependence on initial and boundary data for a one-dimensional dynamic debonding model describing a thin film peeled away from a substrate. The system underlying the process couples the (weakly damped) wave equation with a Griffith’s criterion which rules the evolution of the debonded region. We show that under general convergence assumptions on the data the corresponding solutions converge to the limit one with respect to different natural topologies
On the Approximation of Quasistatic Evolutions for the Debonding of a Thin Film via Vanishing Inertia and Viscosity
No full textIn this paper, we contribute to studying the issue of quasistatic limit in the context of Griffith’s theory by investigating a one-dimensional debonding model. It describes the evolution of a thin film partially glued to a rigid substrate and subjected to a vertical loading. Taking viscosity into account and under suitable assumptions on the toughness of the glue, we prove that, in contrast to what happens in the undamped case, dynamic solutions converge to the quasistatic one when inertia and viscosity go to zero, except for a possible discontinuity at the initial time. We then characterise the size of the jump by means of an asymptotic analysis of the debonding front
New experimental model for basic research in stem cell field
No full textThe great interest in these findings is due to the promising possibility to use MSC in tissue engineering and gene therapy thanksto their plasticity and availability.
Recently a subpopulation of luteinized granulosa cells (GC) derived from infertile patients during their IVF procedures showed mesenchymal stem characteristics and multipotency.I n our recent study a heterogeneous cell population were isolated from human ovarian follicular fluid (FF cells) and cultivated in minimal medium conditions without any growth factors, including leukemia-inhibiting factor. FF cells showed a different morphology, such as fibroblastic, epithelial and also neuronal shape. In particular, the cells with characteristics similar to fibroblasts expressed many specific antigens of mesenchymal stem cells (i.e. CD90, CD44, CD105, CD73) and were negative for haematopoietic and epithelial markers (CD34, CD45, cytokeratins). We confirmed the multipotency of a subset of granulosa cells by in vitro differentiation studies (e.g. osteogenic, chondrogenic and adipogenic differentiation).Therefore we propose follicular fluid cells as a cheap biological experimental model for basic research in stem cells fields thanks to their clonogenic capacity, multipotency and availability without any growth factor addiction too.FF cells could be a good model not only to study biocompatibility of engineering scaffold, but also to investigate the effect induced by mechanical conditioning
Pressure live loads and the variational derivation of linear elasticity
No full textThe rigorous derivation of linear elasticity from finite elasticity by means of gamma-convergence is a well-known result, which has been extended to different models also beyond the elastic regime. However, in these results the applied forces are usually assumed to be dead loads, that is, their density in the reference configuration is independent of the actual deformation. In this paper we begin a study of the variational derivation of linear elasticity in the presence of live loads. We consider a pure traction problem for a nonlinearly elastic body subject to a pressure live load and we compute its linearization for small pressure by gamma-convergence. We allow for a weakly coercive elastic energy density and we prove strong convergence of minimizers
System-dynamics modelling of the electricity-development nexus in rural electrification based on a Tanzanian case study
Full text linkThe rural electrification-based literature reports a limited knowledge of the long-term socio-economic changes that electricity access can bring in remote contexts and the consequent feedback on electricity demand. Such lack of understanding causes an inefficient allocation of economic resources for rural energy projects and inappropriate sizing processes. We model the multifaceted dimensions of the rural electricity-development nexus by formulating a system-dynamics model based on a Tanzanian case-study and using 13-years of data for calibrating it. The modelled structure provides the first quantitative step in the research committed to develop an appropriate modelling framework for deriving policy insights regarding the electricity-development nexus and the evolution of electricity demand for rural areas of developing countries. The simulation results show and highlight the dynamics behind the structural behaviour of some socio-economic system variables (e.g. income and IGAs growth), the exogenous determinants (e.g. accessibility of the rural village), and the complementary activities (e.g. micro-credit at electricity access) that allow electricity access to foster local socio-economic changes, which in turn supports the growth of electricity demand. Our findings allow increasing the understanding on the complex electricity-development nexus and providing a novel modelling framework for projecting the electricity demand for rural settings
Existence and uniqueness of dynamic evolutions for a one-dimensional debonding model with damping
No full textIn this paper we analyse a one-dimensional debonding model when viscosity is taken into account. It is described by the weakly damped wave equation whose domain, the debonded region, grows according to a Griffith’s criterion. Firstly we prove that the equation admits a unique solution when the evolution of the debonding front is assigned. Finally we provide an existence and uniqueness result for the coupled problem given by the wave equation together with Griffith’s criterion
Indice analitico
No full textIndice analitico e ragionato del lessico etico filosofico di Lévinas in Etica e Infinito in rapporto con altre opere
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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