196,425 research outputs found
Systematic numerical investigation of the role of hierarchy in heterogeneous bio-inspired materials
No full textIt is well known that hierarchical structure is an important feature in biological materials to optimise various properties, including mechanical ones. It is however still unclear how these hierarchical architectures can improve material characteristics, for example strength. Also, the transposition of these structures from natural to artificial bioinspired materials remains to be perfected. In this paper, we introduce a numerical method to evaluate the strength of fibre-based heterogeneous biological materials and systematically investigate the role of hierarchy. Results show that hierarchy indeed plays an important role and that it is possible to “tune” the strength of bio-inspired materials in a wide range of values, in some cases improving the strength of non-hierarchical structures considerably
Concorso di idee per un centro socio-ricreativo da realizzare sull’area pubblica denominata Nava
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Materiali strutturali biologici e bioinspirati
No full textI materiali sviluppati dall'uomo e utilizzati per applicazioni tecnologiche, in generale non sono multifunzionali, né tolleranti ai difetti, né auto-riparanti, né auto-pulenti, né gerarchici. Il contrario è vero per i materiali naturali, che manifestano queste proprietà nonostante siano "costruiti" usando un numero limitato di componenti di base estremamente comuni. Una comprensione approfondita del perché sia così potrebbe fornire la chiave per accelerare l'avvento di una nuova era basata su nuovi materiali.Questo è l'obiettivo della ricerca sui materiali bioispirati, che è in continua evoluzione e ha già fatto passi significativi verso questa meta
Review: Michael J. Bosia, Sandra M. McEvoy, and Momin Rahman. The Oxford Handbook of Global LGBT and Sexual Diversity Politics.
No full textIn lieu of an abstract, here is the first paragraph of the article\u27s introduction:
The Oxford Handbook of Global LGBT and Sexual Diversity Politics (2020) edited by M. Bosia, S. McEvoy, and M. Rahman, offers three sections composed of twenty-eight chapters on histories, theories, case studies, and critiques of global LGBT and sexual diversity politics. The handbook’s main intention is to dislodge the centrality of the U.S., and the West in general, in global LGBT studies. The editors therefore support a more inclusive perspective through case studies of a decentralized ‘global’ LGBT world
Nucleation dynamics in 2d cylindrical Ising models and chemotaxis
No full textThe aim of our work is to study the effect of geometry variation on nucleation times and to address its role in the context of eukaryotic chemotaxis (i.e. the process which allows cells to identify and follow a gradient of chemical attractant). As a first step in this direction we study the nucleation dynamics of the 2d Ising model defined on a cylindrical lattice whose radius changes as a function of time. Geometry variation is obtained by changing the relative value of the couplings between spins in the compactified (vertical) direction with respect to the horizontal one. This allows us to keep the lattice size unchanged and study in a single simulation the values of the compactification radius which change in time. We show, both with theoretical arguments and numerical simulations that squeezing the geometry allows the system to speed up nucleation times even in presence of a very small energy gap between the stable and the metastable states. We then address the implications of our analysis for directional chemotaxis. The initial steps of chemotaxis can be modelled as a nucleation process occurring on the cell membrane as a consequence of the external chemical gradient (which plays the role of energy gap between the stable and metastable phases). In nature most of the cells modify their geometry by extending quasi-onedimensional protrusions (filopodia) so as to enhance their sensitivity to chemoattractant. Our results show that this geometry variation has indeed the effect of greatly decreasing the timescale of the nucleation process even in presence of very small amounts of chemoattractants
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