Search results for "CONTACT"
showing 10 items of 1003 documents
A non-linear Ritz method for the analysis of low velocity impact induced dynamics in variable angle tow composite laminates
2021
Abstract Variable angle tow (VAT) laminates feature composite layers reinforced by fibres following continuous curved paths and offer a wide structural design space for the manufacturing of composite components. In this work, a formulation for the analysis of the impact-induced dynamics in VAT laminated plates is proposed, implemented and tested in this work. The method is based on the adoption of first order shear deformation kinematics and includes von Karman non-linear strains. The discrete system is obtained by employing a pb-2 Ritz series expansion into the Hamilton’s variational statement, while the impact loading is modelled through Hertzian contact law. The resulting non-linear gove…
Carbon nanotube field-effect devices with asymmetric electrode configuration by contact geometry
2014
We have studied experimentally the conductive properties of single walled carbon nanotube (SWNT) based field-effect type devices, with different contact geometries at the connecting electrode. The device designs are asymmetric with one end of the SWNT having the metal electrode deposited on top and immersing it, while at the other end, the SWNT is on top of the electrode. The devices were made with either gold or palladium as electrode materials, of which the latter resulted in different behavior of the different contact types. This is argued to be caused by the existence of a thin insulating layer of surface adsorbents on the palladium, possibly Pd5O4, the effect of which is enhanced by th…
Time-dependent current-voltage characteristics of Al/p-CdTe/Pt x-ray detectors
2012
Current-voltage (I-V) characteristics of Schottky Al/p-CdTe/Pt detectors were investigated in dark and at different temperatures. CdTe detectors with Al rectifying contacts, very appealing for high resolution x-ray and gamma ray spectroscopy, suffer from bias-induced polarization phenomena which cause current increasing with the time and severe worsening of the spectroscopic performance. In this work, we studied the time-dependence of the I-V characteristics of the detectors, both in reverse and forward bias, taking into account the polarization effects. The I-V measurements, performed at different time intervals between the application of the bias voltage and the measurement of the current…
El contacte entre la Ribera del Xúquer i els raiguers de les Muntanyes de Carcaixent
1985
Cuando el río Xúquer llega a la Ribera, deja el encajamiento montañoso y forma un cono aluvial que ent ra en contacto con los piedemontes originados por los relieves emergidos en las cercanías de la llanura de inundación, apareciendo unas zonas deprimidas en el punto de contacto de las dos formaciones por los perfiles opuestos que presentan. Además, el contacto no es estable debido a la diferente velocidad de crecimiento en altura, y en consecuencia los depósitos fluviales conquistan poco a poco las tierras de piedemonte y por lo tanto, la zona deprimida se aleja cada vez más del río. En segundo lugar, los núcleos de población, que hace muchos años estaban al margen de las inundaciones por …
Parameters analysis influencing 3D measurement without contact by laser scanner to establish a local correction procedure
2007
International audience; The techniques of measuring without contact by laser scanning allows acquisition of a large number of points, at a very high rate speed ; nevertheless with less precision than the one obtained by classical techniques of measuring with contact. We present in this article the research and the experimental analysis of the influential parameters on the precision of the measure by laser sensor without contact. Firstly, a methodology of correction of the relative uncertainties in the conditions of the measuring laser is presented. Then, we apply it to a typical part and compare the results to those obtained by a classical procedure of measuring with a contact sensor. We fi…
Contact laws between nanoparticles: the elasticity of a nanopowder
2018
International audience; Studies of the mechanical contact between nanometer-scale particles provide fundamental insights into the mechanical properties of materials and the validity of contact laws at the nanoscale which are still under debate for contact surfaces approaching atomic dimensions. Using in situ Brillouin light scattering under high pressure, we show that effective medium theories successfully predict the macroscopic sound velocities in nanopowders if one takes into account the cementation of the contacts Our measurements suggest the relevance of the continuum approach and effective medium theories to describe the contact between nanoparticles of diameters as small as 4 nm, i.e…
Toward the development of a remote photoplethysmographic sensor
2019
Heart-rate estimation performed with remote photoplethysmography is a very active research field. Since pioneer works in 2010, which demonstrated the feasibility of the measure with low-grade consumers’ camera (webcam), the number of scientific publications have increased significantly in the domain. Hence, we observe a multiplication of the methods in order to retrieve the photoplethysmographic signal which hasled to an increased precision and quality of the heartrate estimation. Region of interest segmentation is a key step of the processing pipeline in order to maximize the quality of the measured signal. We propose a new method to perform remote photoplethysmographic measurement using a…
Vers le développement d'un capteur photoplétysmographique sans contact
2019
Heart-rate estimation performed with remote photoplethysmography is a very active research field. Since pioneer works in 2010, which demonstrated the feasibility of the measure with low-grade consumers’ camera (webcam), the number of scientific publications have increased significantly in the domain. Hence, we observe a multiplication of the methods in order to retrieve the photoplethysmographic signal which has led to an increased precision and quality of the heart-rate estimation. Region of interest segmentation is a key step of the processing pipeline in order to maximize the quality of the measured signal. We propose a new method to perform remote photoplethysmographic measurement using…
Estimation de la densité du Blaireau (Meles meles) en Côte d’Or au regard du risque de transmission de la tuberculose bovine
2012
Rapport de Stage de Master 2 EA MERS CT3; Master
La Bourgogne entre les bassins rhénan, rhodanien et parisien : carrefour ou frontière ?
1996
International audience; Au coeur même de son territoire, la région de Bourgogne a accueilli pour quelques jours, à l'occasion de son 18e colloque, la communauté des néolithiciens. Bien des congressistes, venus du Nord, de l'Ouest ou du Sud pour se rendre à Dijon, n'auront pas manqué de percevoir le relatif obstacle au franchissement que constitue le massif bourguignon.Mais le frein partiel engendré par la topographie ne saurait masquer l'ouverture vers l'extérieur de la Bourgogne, naturellement échancrée par trois bassins alluviaux. La Seine, l'Yonne et leurs affluents constituent des vallées propices aux échanges avec le Bassin parisien. Le couloir de la Saône, prolongé par celui du Rhône,…