Search results for "COMPRESSION"

Recristallisation Dynamique au Cours de la Déformation à Chaud de Quatre Nuances de Bronze à 9% d'Etain

1995

Pour cerner les techniques metallurgiques des artisans protohistoriques, il est necessaire de connaitre les evolutions microstructurales obtenues selon les deformations imposees. La compression a chaud de deux bronzes industriels (contenant soit 0,026% soit 0,26% de zinc) et deux bronzes «archeologiques» (contenant soit 0,5% de soufre soit 0,5% de soufre et 0,5% de plomb) permet les observations suivantes : - Les comportements des bronzes «archeologiques» sont tres similaires : jusqu'a 600°C pour e = 0,1 on n'observe pas de recristallisation ; pour e = 1,2 on observe une recristallisation en collier le long des joints de grains. A 750°C la recristallisation semble homogene dans tout le mate…

Experimental investigation on BFRCM confinement of masonry cylinders and comparison with BFRP system

2021

Abstract Fabric reinforced cementitious mortar (FRCM) materials have started to be employed during the last years with the aim of overcoming the drawbacks related to the use of fibre reinforced polymer (FRP) composites, proving to be potentially suitable for strengthening masonry structures. Moreover, the will to develop materials able to guarantee a certain degree of sustainability without renouncing to adequate mechanical properties has drawn the attention to the use of basalt fibres, which appear to be a valid alternative to carbon or glass fibres. This work presents an experimental investigation on a basalt FRCM (BFRCM) system to confine circular masonry columns, aimed at evaluating the…

Repetitiveness Measures based on String Attractors and Burrows-Wheeler Transform: Properties and Applications

2023

A supercritical-fluid method for growing carbon nanotubes

2007

Large‐scale generation of multiwalled carbon nanotubes (MCNTs) is efficiently achieved through a supercritical fluid technique employing carbon dioxide as the carbon source. Nanotubes with diameters ranging from 10 to 20 nm and lengths of several tens of micrometers are synthesized (see figure). The supercritical‐fluid‐grown nanotubes also exhibit field‐emission characteristics similar to MCNTs grown by chemical‐vapor deposition.

On the analysis of Catalan thin vaults

2010

This paper is concerned with the identification, modelling and analysis of thin layered vaults, typical in the Catalan constructions of the XIX century. These special structures, also known as bovedas tabicadas, are characterized by very low thickness with respect to the medium surface dimensions and by the presence of different superimposed layers of bricks tied with mortar, are studied in order to individuate a coherent mechanical model for describing the material behaviour, to recognize the structural response utilizing as comparison adequate experimental results, and to extend the obtained results for the analysis of new vaults or for the restoration design of existing vaults. Firstly, …

Failure Analysis of a Humeral Shaft Locking Compression Plate—Surface Investigation and Simulation by Finite Element Method

2019

A case study of a failed humeral shaft locking compression plate is presented, starting with a clinical case where failure occurred and an implant replacement was required. This study uses finite element method (FEM) in order to determine the failure modes for the clinical case. Four loading scenarios that simulate daily life activities were considered for determining the stress distribution in a humeral shaft locking compression plate (LCP). Referring to the simulation results, the failure analysis was performed on the explant. Using fracture surface investigation methods, stereomicroscopy and scanning electron microscopy (SEM), a mixed mode failure was determined. An initial fatigue failu…

Numerical and theoretical considerations on the surface energy for pure solids under strain

2004

In this paper we developed a numerical analysis, by means of molecular dynamics (MD) simulations, for the surface energy of solids when a stress is applied parallel to the surface. Our MD simulations for Al showed that under these conditions; compression or an alternation of compression and tension, with respect to the bulk, of some atomic layers below the surface is present. Moreover, we quantified the surface energy variations that led us to propose an empirical model.

Wavelet-like efficient analysis of two-dimensional arbitrarily shaped radomes using a surface formulation

2007

[1] Radomes are usually made of lossy dielectric materials, and their accurate analysis is often cumbersome because of their typical large electrical size and geometrical complexity. In real reflector antenna structures, there are always complex interactions between the radome, the reflector surfaces and the directional feeds, which are typically neglected for the sake of simplicity. In this paper we will consider all such interactions in a very accurate way, thus requiring a high number of unknowns for the numerical solution of the problem. To overcome such drawback, an integral equation formulation based on the Equivalence Principle in combination with the wavelet transform has been emplo…

Estimation de surface de Bézier à partir d'images de lumière structurée dans une optique de compression

2013

National audience; Compression of 3D datas has become a topic of increasing importance over the evolution of scanners. With evolution of technologies, the commercial scanners give more and more data points, which can lead to difficulties in transmission or storage. In most cases, the acquisition does not take into account the final use of the data. While in many cases, this would limit the number of points. In this paper, we propose an approach which simplifies the scatterplot for industrial purposes using Bezier surfaces.

Semiparametric Models with Functional Responses in a Model Assisted Survey Sampling Setting : Model Assisted Estimation of Electricity Consumption Cu…

2010

This work adopts a survey sampling point of view to estimate the mean curve of large databases of functional data. When storage capacities are limited, selecting, with survey techniques a small fraction of the observations is an interesting alternative to signal compression techniques. We propose here to take account of real or multivariate auxiliary information available at a low cost for the whole population, with semiparametric model assisted approaches, in order to improve the accuracy of Horvitz-Thompson estimators of the mean curve. We first estimate the functional principal components with a design based point of view in order to reduce the dimension of the signals and then propose s…