Centre de Transfert de Technologie du Mans

The use of low frequency waves is the most practical means to investigate nonlinear elastic properties of hysteretic media, such as the strain dependence of wave velocity. Indeed, the rapid increase in damping as a function of frequency makes high frequency waves unable to provide sufficient strain energy to successfully excite nonlinearity. The drawback is that low frequency waves are not suitable for imaging, due to their long wavelength and resulting intrinsic averaging of nonlinear effects over large spatial scales. To address this, we propose here an amplitude modulation of swept sources that allows us to correlate the frequency at which harmonics are detected with the position of the source of nonlinearity, taking advantage of the different strain distributions in the sample at different frequencies.

Le transfert de technologie entre régions industrielles a généré des études relativement nombreuses dans les cas où les centres émetteurs étaient le Royaume-Uni ou la France. Ces pays ajoutent à leur situation de pays industriellement avancés leur présence parmi les principales puissances politiques. Cependant, lorsque le flux s’amorce à partir de régions économiquement développées mais moins influentes, comme dans le cas de la Belgique, la littérature scientifique existante est beaucoup moins abondante. Il s'agit ici de mettre en évidence comment les premiers éléments de l'exploitation industrielle moderne des mines des Asturies se sont imposés en prenant appui sur les méthodes industrielles belges.

Smart manufacturing is a part of the fourth industry revolution (Industry 4.0), which offers promising perspectives for high reliability, availability, maintainability, and safety production process. Indeed, smart monitoring methods, that are implemented in this kind of manufacturing process, allow efficient tracking of a system degradation in real time through appropriate sensors. Then, the sensor data are analyzed and processed to extract effective health indicators for fault detection, diagnostic and prognostics. This paper aims to develop a practical methodology for constructing a new health indicator based on heterogeneous sensor measurements to efficiently monitor system states. The proposed methodology is applied to extract the health indicator of a robot cutting tool (i.e. end-flat mill). This indicator is then used to diagnose the different fault types of the tool by an adaptive neuro-fuzzy inference system model.

The main objective of this paper was to illustrate the enhancement of the sensitivity of the ELISA titration of Tau proteins while reducing other non-specific adsorptions that could increase the optical densities and could lead to false positives. This goal was obtained thanks to the association of cold plasma and wet chemistries of the inner surface of the titration well. The PP surface was cold plasma-activated, then coated with different amphiphilic molecules bearing either ionic charges and/or long hydrocarbon chains. The support treated and coated with hexatrimethylammonium bromide improves the signal detection of proteins while reducing the background due to non-specific associations of biomolecules such as hyperphosphorylated Tau protein. However, coating with 3-butenylamine hydrochloride could also be suitable.

Summary form only given, as follows. An original 3D pyramidal geometry for a low loss and compact filter is described in this paper. Thanks to the 3D ceramic stereolithography process, high unloaded quality factor resonators have been fabricated into a low footprint 4-pole Chebyshev filter. The 3D technologies used for manufacturing the filters in one ceramic part; their plating and etching has lead to a low insertion loss filter working at 17.5 GHz. This paper goes into details on this filter dedicated to space applications.

The standard two microphones technique does not allow the measurement of absorbing materials characteristics at low frequency. Moreover, to cover a range from 100 to 6000 Hz two experiments have to be done with two different sample diameters. By using a sensor with a known volume velocity source developed by the LAUM together with the CTTM, it is demonstrated that the impedance can be obtained from 10 to 6000 Hz by performing only one measurement with a single material sample. Results showing the behaviour of some materials at low frequency are presented. On the other hand a comparison is done with classical Kundt tube results.

The possibility of biosurfaces with high or low adhesiveness for protein, bacteria or eukaryotic cells is discussed. At the interface surface object/biological milieu, biocompatibility, (no) bioadhesion and (no) biocontamination are shown to be correlated with physico-chemical surface characteristics. First consequence is the (no) possibility of biofilm formation. Substrates with low surface energy could interact only with hydrophobic biomolecules. On substrates with high surface energy, a water monolayer spontaneously formed. Modification of a surface by plasma techniques is a way for engineering biomaterials. Plasma techniques are dry processes and more suitable for biomedical applications. In the field of biomaterial medical devices, in hygienic prevention of nosocomial diseases, in food packaging, the use of substrates with a very hydrophilic character may help to prevent the proliferation of cells and bacteria. Such a technique is so efficient that antibiotic molecules are not necessary. Therefore, surface engineering is a tool for modifying and adapting materials to specific biological applications.

Polymers are widely used in medicine for vascular prostheses, bone substitutes, and devices for controlled release. Among these polymers, poly(2-hydroxyethyl methacrylate) (pHEMA) is the most employed. To confer particular properties, pHEMA can be copolymerized with other monomers or in the presence of plasticizers or crosslinking agents. The influence of the length of crosslink chains on swelling, surface rugosity, hardness, and stiffness of crosslinked pHEMA were studied by several techniques, including fractal analysis and AFM. Four crosslinking agents (divinyl benzene, DVB; ethylene glycol dimethacrylate, EGDMA; tetraethylene glycol diacrylate, TEGDA; and polyethylene glycol diacrylate, PEGDA) were added to the bulk polymerization mixture. Only linear and PEGDA-pHEMA presented a significant decrease in surface roughness confirmed by fractal analysis. Differences in hardness and biomechanical properties were evidenced on dried polymers but the highest differences were exhibited for hydrated pHEMA. Correlations between the length of the crosslink chain and hardness or stiffness of hydrated crosslinked pHEMA were evidenced. TEGDA and PEGDA appeared to be the two most suitable crosslinking agents for controlled release of bioactive molecules in bone.