Search results for " Elasticity"

Liquid Crystalline Elastomers

1989

Today, material science is directed towards the development of multifunctional and oriented structures. One example of such supramolecular systems are liquid crystalline (LC) elastomers which combine the properties of LC phases (the combination of order and mobility) with rubber elasticity, one of the most typical polymer properties. Their most outstanding characteristic is their mechanical orientability; strains as small as 20% are enough to obtain a perfectly oriented LC monodomain. This orientability, if LC elastomers with chiral phases are used, leads, for example, to elastomers with chiral smectic C* phases which are likely to show piezo-electric behavior.

Disentangling the Role of Chain Conformation on the Mechanics of Polymer Tethered Particle Materials

2019

[Image: see text] The linear elastic properties of isotropic materials of polymer tethered nanoparticles (NPs) are evaluated using noncontact Brillouin light spectroscopy. While the mechanical properties of dense brush materials follow predicted trends with NP composition, a surprising increase in elastic moduli is observed in the case of sparsely grafted particle systems at approximately equal NP filling ratio. Complementary molecular dynamics simulations reveal that the stiffening is caused by the coil-like conformations of the grafted chains, which lead to stronger polymer–polymer interactions compared to densely grafted NPs with short chains. Our results point to novel opportunities to …

Ferroelectric LC-elastomers

1997

Ferroelectric liquid crystalline elastomers combine the rubber elasticity of polymer networks with liquid crystalline phases and ferroelectric ordering. Ferroelectric switching leads therefore to a deformation of the polymer network and an elastic stress. The coupling between both effccts can be varied by changing the topology of the netpoints.

NEW EU MEMBER COUNTRIES ARE PHASING OUT LABOR-INTENSIVE ACTIVITIES: AN ECONOMETRIC APPROACH

2012

This paper deals with the process of industrial development that has been unfolding in Central and East-European Countries during the last two decades, with special focus on changes in international specialization induced by successive shifts in comparative advantage. As it was to be expected, these advances have gradually improved the respective countries’ exports structure, the most important mutation residing in the gradual abandoning of subcontracting agreements – mostly confined to assembly-of-imported-inputs – and the expansion of the production of knowledge and human capital-intensive goods and services. European integration has most certainly been acting as a catalyst for this proce…

The elasticity of a random variable as a tool for measuring and assessing risks

2022

Elasticity is a very popular concept in economics and physics, recently exported and reinterpreted in the statistical field, where it has given form to the so-called elasticity function. This function has proved to be a very useful tool for quantifying and evaluating risks, with applications in disciplines as varied as public health and financial risk management. In this study, we consider the elasticity function in random terms, defining its probability distribution, which allows us to measure for each stochastic process the probability of finding elastic or inelastic situations (i.e., with elasticities greater or less than 1). This new tool, together with new results on the most notable p…

Il modulo elastico statico e dinamico del calcestruzzo

2012

An explicit mechanical interpretation of Eringen non-local elasticity by means of fractional calculus

2009

If the attenuation function of strain is expressed as a power law, the formalism of fractional calculus may be used to handle Eringen non-local elastic model. Aim of the present paper is to provide a mechanical interpretation to this non-local fractional elastic model by showing that it is equivalent to a discrete, point-spring model. A one-dimensional geometry is considered; static, kinematic and constitutive equations as well as the proper boundary conditions are derived and discussed.

Elasticity and revenue: do we need a reappraisal?

2002

The relationship between price-elasticity of demand, price variations and total revenue changes might be considered as one of the most widely accepted results arising from consumer theory. Recently, however, this relationship has been put under suspicion on the basis of a misinterpretation of what economists have in mind when writing about it. In this paper we try to clarify concepts incorporating new elements into discussion with the aim of reaffirming the validity of this relationship.

Approximation of pre-twisted Achilles sub-tendons with continuum beam elements

2022

Achilles sub-tendons are materially and geometrically challenging structures that can nearly undergo around 15% elongation from their pre-twisted initial states during physical activities. Sub-tendons' cross-sectional shapes are subject-specific, varying from simple to complicated. Therefore, the Achilles sub-tendons are often described by three-dimensional elements that lead to a remarkable number of degrees of freedom. On the other hand, the continuum-based beam elements in the framework of the absolute nodal coordinate formulation have already been shown to be a reliable and efficient replacement for the three-dimensional continuum elements in some special problems. So far, that element …

<p>Shock Waves as a Treatment Modality for Spasticity Reduction and Recovery Improvement in Post-Stroke Adults – Current Evidence and Qualitati…

2020

Purpose: This systematic review examines intervention studies using extracorporeal shock wave therapy (ESWT) application in post-stroke muscle spasticity with particular emphasis on the comparison of two different types of radial (rESWT) and focused shock waves (fESWT). Methods: PubMed, PEDro, Scopus, and EBSCOhost databases were systematically searched. Studies published between the years 2000 and 2019 in the impact factor journals and available in the English full-text version were eligible for inclusion. All qualified articles were classified in terms of their scientific reliability and methodological quality using the PEDro criteria. The PRISMA guidelines were followed and the registrat…