Search results for "mecA"
showing 10 items of 475 documents
Functional principal component analysis as a new methodology for the analysis of the impact of two rehabilitation protocols in functional recovery af…
2014
[EN] Background: This study addressed the problem of evaluating the effectiveness of two protocols of physiotherapy for functional recovery after stroke. In particular, the study explored the use of Functional Principal Component Analysis (FPCA), a multivariate data analysis in order to assess and clarify the process of regaining independence after stroke. Methods: A randomized double-blind controlled trial was performed. Thirteen subjects with residual hemiparesis after a single stroke episode were measured in both in- and outpatient settings at a district hospital. All subjects were able to walk before suffering the stroke and were hemodynamically stable within the first week after stroke…
Mecanismos de coordinación estructural, no estructural e informal: Propuesta y validación de escalas de medida
2008
RESUMENEl presente trabajo tiene como objetivo diseñar y validar escalas para medir diversos mecanismos de coordinación estructural, no estructural e informal. Los primeros están vinculados a puestos u órganos específicos, y nos referimos al diseño de redes, equipos de proyecto y desarrollo, y equipos de trabajo. Los mecanismos de coordinación no estructural sirven de complemento a los anteriores. En este grupo se encuentran la normalización de procesos de trabajo, de habilidades y de resultados. Por último, los mecanismos de carácter informal son el esfuerzo de socialización y la adaptación mutua. Tras la generación de una batería de 43 ítems, se han comprobado sus propiedades psicométrica…
Elucidating the Effect of Bimodal Grain Size Distribution on Plasticity and Fracture Behavior of Polycrystalline Materials
2020
The refinement of grains in a polycrystalline material leads to an increase in strength but as a counterpart to a decrease in elongation to fracture. Different routes are proposed in the literature to try to overpass this strength-ductility dilemma, based on the combination of grains with highly contrasted sizes. In the simplest concept, coarse grains are used to provide relaxation locations for the highly stressed fine grains. In this work, a model bimodal polycrystalline system with a single coarse grain embedded in a matrix of fine grains is considered. Numerical full-field micro-mechanical analyses are performed to characterize the impact of this coarse grain on the stress-strain const…
A new hyperelastic model for anisotropic hyperelastic materials with one fiber family
2016
International audience; The main goal of this study is to propose a practical application of a new family of transverse anisotropic invariants by designing a strain energy function (SEF) for incompressible fiber-reinforced materials. In order to validate the usability and creativeness of the proposed model, two different fiber-reinforced rubber materials under uniaxial and shear testing are considered. For each kind of material, numerical simulations based on the proposed model are consistent with experimental results and provide information about the effect of the new family of invariants in the construction of the SEF.
Experimental analysis of acoustical properties of irregular cavities using laser refracto-vibrometry
2018
International audience; In this paper, the Scanning Laser Doppler Vibrometer (SLDV) is used to measure acoustic pressure in small regions of cavities for the study of acoustical localization. It is shown that this optical method leads to interesting information on localized acoustical modes inside irregular cavities, which are very difficult to observe using conventional microphone measurements. Indeed, localization regions are often of comparable size or even smaller than a typical microphone which can make this type of sensor intrusive. The SLDV is used to measure sound pressure after deriving the refracto-vibrometry method from its standard use. Data are obtained in a large area with a h…
Acoustics of porous materials with partially opened porosity
2013
International audience; A theoretical and experimental study of the acoustic properties of porous materials containing dead-end (or partially opened) porosity was recently proposed by Dupont et al. The present article provides a description of partially opened porosity systems and their numerous potential applications in the general context of the study of porous materials, the classical models describing them, and the characterization techniques. It is shown that the dead-end pore effect can be treated independently and that the description of this effect can be associated with any acoustic model of porous media. Different theoretical developments describing the dead-end porosity effect ar…
Influence of modification time and high frequency ultrasound irradiation on self-assembling of alkylphosphonic acids on stainless steel : electrochem…
2015
International audience; Self-assembly of alkylphosphonic acids on stainless steel was investigated under different conditions. Four different alkylphosphonic acids exhibiting alkyl chain of various size were synthesized and studied: butylphosphonic acid (C4P), octylphosphonic acid (C8P), decylphosphonic acid (C10P), and hexadecylphosphonic acid (C16P). Electrochemistry experiments were extensively carried out in order to determine electrochemical surface blocking of adsorbed layers in function of grafting time. In term of surface blocking, an 8h modification time was optimal for all alkylphosphonic acids. Longer immersion times lead to degradation of adsorbed layers. For the first time, gra…
A new method for Poisson’s ratio measurement with time-of-flight technique: application to the preliminary design of smart composite structures
2019
International audience; Smart composite structures, which are able to modify their mechanical properties with respect to their environment (e.g. active vibration control), to interact with other structures (e.g. mechatronic) or with human beings (e.g. Human-Machine Interaction), are widely used in the modern industrial fields (e.g. aerospace), due to the intensification of the operational dynamic environment and an increase of durability requirements from the customers. Conventionally, the piezoelectric transducers are glued on the surface of the structure and the power and control electronics are away. To protect the transducer elements and their connections and develop some industrially p…
Epoxy Resin/Carbon Black Composites Below the Percolation Threshold
2013
International audience; A set of epoxy resin composites filled with 0.25-2.0 wt.% of commercially available ENSACO carbon black (CB) of high and low surface area (CBH and CBL respectively) has been produced. The results of broadband dielectric spectroscopy of manufactured CB/epoxy below the percolation threshold in broad temperature (200 K to 450 K) and frequency (20 Hz to 1 MHz) ranges are reported. The dielectric properties of composites below the percolation threshold are mostly determined by alpha relaxation in pure polymer matrix. The glass transition temperature for CB/epoxy decreases in comparison with neat epoxy resin due to the extra free volume at the polymer-filler interface. At …
SEGREGATION CONTROL AT DIRECTIONAL SOLIDIFICATION USING MAGNETIC FIELD AND ELECTRIC CURRENT
2015
International audience