1,721,063 research outputs found
Preface
No full textThe essays collected in these two volumes provide evidence of Patrizia Lendinara’s wide expertise and her impact in distinct academic fields, ranging from late antiquity to the early and late Middle Ages. The papers are offered as a tribute to Patrizia’s scholarship by colleagues from Italy and abroad, some of whom were once her students. The theme of this Festschrift was chosen in view of the honouree’s keen interest in and contribution to the study of the glosses and the lexicon of Germanic languages. Accordingly, although the essays collected in these volumes vary quite widely in both style and structure, they all ultimately focus on the various facets of glossography and lexicography of the medieval Germanic world
Studies on Late Antique and Medieval Germanic Glossography and Lexicography in Honour of Patrizia Lendinara
No full textThis is a multilingual two-volume collection assembling 43 contributions on late antique and early medieval Germanic glossography and lexicography by the major experts in the field from Europe and North America. The essays present cutting edge research on a diverse of range of topics concerning the lexicon and the glossographical production in the late antique and early medieval Germanic world with a special emphasis on the relationship between the latter and the legacy of the classical world. The volumes are complemented with a very useful set of indexes (index of manuscripts and index of authors and works)
Morphing of soft tubes by anisotropic growth
No full textWe present a study of smart growth in layered cylindrical structures. We start from the characterization of a compatible growth field in an anisotropic growing tube with the aim to show a small perturbation in the compatible growth field that may produce a controlled deprivation of compatibility and localization of elastic energy storage in a composite structure made up of anisotropic growing tubes
Stress-free morphing by means of compatible distortions
No full textWe study the morphing of three-dimensional objects within the framework of nonlinear elasticity with large distortions. A distortion field induces a target metric, and the configuration which is effectively realized by a material body is the one that minimizes the distance, measured through the elastic energy, between the target metric and the actual one. Morphing through distortions might have a paramount feature: the resulting configurations might be stress-free; if this is the case, the distortions field is called compatible. We maintain that the morphing through compatible distortions is a key strategy exploited by many soft biological materials, which can exhibit very large shape-change in response to distortions controlled by stimuli such as chemicals or temperature changes, while keeping their stress state almost null. Thus, the study of compatible distortions, and of the related shape-changes, is quite important. Here, we show a blueprint for stress-free morphing based on the notions of metric tensor and of Riemann curvature which can be used to design large morphing of three-dimensional objects
Elastic Energies for Nematic Elastomers
No full textWe discuss several elastic energies for nematic elastomers and their small strain expansions both in the regime of large director rotations, and in the case that director changes are small. We propose two fully non-linear model anisotropic energies and compare the behavior they predict with the currently available experimental evidence
Mechanics of active gel spheres under bulk contraction
No full textIn active gels, liquid redistribution, network deformation and material remodeling due to bulk activation, mimicking the presence of molecular motors, are strongly coupled. We present a consistent mathematical model capable to gain a deep understanding of the phenomenon in both steady and transient conditions. With explicit reference to active gel spheres, we evidence the role that not uniform bulk activation may have in generating local stress or strain actuators based on liquid redistribution
Torsional deformations in incompressible fibre--reinforced cylindrical pipes
No full textThe first part of the paper deals with an extension of the classical Rivlin’s solution of the torsion problem of a neo-Hookean pipe. The second part concerns a study of the passive torsional deformation processes in a fibre-reinforced cylindrical dummy of the beating heart. Especially, the dependence of the torsional and volumetric stiffness of the cylindrical pipe on different geometric and material parameters is discussed through a set of numerical simulations
A mechanical modeling of pressure-volume loop
No full textA reduced–order heart model aimed to introduce a novel point of view in the interpretation
of the pressure–volume loops is presented. The novelty of the approach is based on the definition
of active contraction as opposed to that of active stress. The consequences of such assumption are
discussed with reference to a specific PV loop characteristic of a normal human patien
Mathematical model for isometric and isotonic muscle contractions
No full textA new mathematical model is presented to describe both the active and passive mechanics of muscles. In order to account for the active response, a two–layer kinematics that introduces both the visible and rest lengths of the muscle is presented within a rational mechanics framework. The formulation is based on an extended version of the principle of virtual power and the dissipation principle. By using an ac- curate constitutive description of muscle mobility under activation, details of microscopic processes that lead to muscle contraction are glossed over while macroscopic effects of chemical/electrical stimuli on muscle mechanics are retained. The model predictions are tested with isometric and isotonic experimen- tal data collected from murine extensor digitorum muscle. It is shown that the proposed model captures experimental observations with only three scalar parameters
Shape deformation from metric ’s transport
No full textWe exploit the possibility of deforming a solid volume, or a surface as well, by assigning a target metric. Aswell known, an elastic solid may change its shape under two different kinds of actions: one are the loadings, the other one are the distortions, aka, the pre-strains. Actually, a distortion prescribes the target metric sought by the solid, and the metric effectively realized is the one that minimize the distance, measured through an elastic energy, between the target metric and the actual one. The challenge of our work is to use the metric information taken from a pair of configurations , of a given body , to deform a different body , so that its deformation be as similar as possible to the one suffered by . In particular, we assess the metric change between the two configurations , of the template ; then, we use this information to build a target metric for , exploiting the notion of distortions: given a source configuration , we find a target configuration by minimizing an appropriate elastic energy. The proposed method is very effective in deforming solids as well as surfaces, and in reproducing similar deformations even when applied to different bodies
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