ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

Metal-inorganic-organic core–shell material as efficient matrices for CO2 adsorption: Synthesis, properties and kinetic studies

Abstract: A novel hydrochar-based core–shell material with improved affinity towards CO2 was synthesized through encapsulation within ZnO shell, followed by chemical grafting to an organic moiety bearing terminal diethanolamino groups and further dispersion of Cu0 nanoparticles. Characterization through nitrogen adsorption–desorption isotherms with BET and BJH models, SEM, TEM, zeta potential measurements, FTIR spectroscopy, DSC and XPS analyses revealed a strong influence of the modification procedure on the performance of each material in CO2 adsorption. The resulting metal-inorganic-organic-core–shell (MIOCS) displayed compacted structure with a wide pore size distribution that imposes intraparticle diffusion as a kinetic-controlling step. Cu-MIOCS showed an appreciable CO2 retention capacity of 5.42 mmol/g compared to many adsorbents reported so far. This affinity towards CO2 was explained in terms of physical and non-stoichiometric CO2 condensation. This finding is of great importance, because it demonstrates that judicious modifications of vegetal-deriving wastes such as woods and other biomasses give rise to added-value materials as low cost and efficient gas adsorbents with high affinity towards CO2.

Automated estimation of regional mean transition times and radial velocities from cine magnetic resonance images: evaluation in normal subjects.

Abstract: Purpose To assess regional ventricular function via an accurate and automated definition of functional parameters. Materials and Methods An automated method is proposed that estimates reliable regional normalized mean transition times (Fmc) and mean radial velocities (Vm) from cine images. This approach combines a quantitative parametric imaging method and an automated detection of the endocardial border, which is robust to the presence of papillary muscles and nonhomogeneities within the left ventricular cavity. Steady-state free-precession cine-magnetic resonance imaging (MRI) of 36 healthy subjects was analyzed. Results The quality of the automated segmentation was assessed on a subgroup of 20 subjects by comparing the results with the manual contours traced by an expert. The comparison of functional parameters estimated consequently using the automated and the manual contours yielded (y = 0.959x + 0.016, R = 0.964) for Fmc and (y = 0.883x + 0.505, R = 0.935) for Vm. On the entire group, Fmc was equal to 0.392 ± 0.069 and Vm to 5.4 ± 2.3 cm/s. Increasing values of the temporal parameter from the apex to the base and larger values in the septal wall than in lateral wall were demonstrated and were in accordance with the physiology. Conclusion The proposed method ensures an automated and robust assessment of regional wall motion parameters, which could be clinically useful. J. Magn. Reson. Imaging 2009;30:236–242. © 2009 Wiley-Liss, Inc.

The effect of microstructural heterogeneities on the High Cycle Fatigue scatter of cast aluminium alloys: from an elementary volume to the structure

Abstract: Cast Al-Si alloys have been widely used in automobile applications thanks to their low density and excellent thermal conductivity. A lot of components made of these alloys are subjected to cyclic loads which can lead to fatigue failure. Furthermore, the well know size effect in fatigue, whereby the fatigue strength is reduced in proportion to an increase in size, can be important. This is caused by a higher probability of initiating a crack in larger specimens (i.e. statistical size effect). This paper analyses the role of casting defects on the statistical size effect. For that, a uniaxial fatigue testing campaign (R=0.1) has been conducted using two cast aluminium alloys, fabricated by different casting processes (gravity die casting and lost foam casting), associated with the T7 heat treatment, and with different degrees of porosity. Different specimens (smooth and notched) with different stressed volumes have been investigated. The first part of this article is dedicated to the experimental characterization of the statistical size effect in both alloys via the concept of the Highly Stressed Volume. The second part investigates the effect of the Highly Stressed Volume on the critical defect size via diagram of Kitagawa-Takahashi. The results show that the presence of statistical size effect is strongly linked to the characteristics of the pore population present in the alloy. A numerical approach, linking the observed pore distribution to the volume of loaded material, is proposed and discussed.

Differentiated haptic stimulation by modal synthesis of vibration field

Abstract: To date, Several focusing techniques have been proposed to realize localized stimulation on haptic interfaces: phased arrays of actuators with delayed excitation, or time reversal techniques which require a preliminary learning phase. Additionally, these techniques are sensitive to parameters variation and disturbances. Modal decomposition allows to realize arbitrary vibration fields congruent with the boundary conditions and in this paper, Modal decomposition is proposed to realize a desired vibration velocity field in order to have differentiated stimuli. The experimental results validate the ability of the method to approximate satisfactorily a desired reference form. The psychophysical evaluations show that users can differentiate and localize the stimulation while exploring a surface with two fingers.

A space for silence: exhibiting and materialising silence through technology:

Abstract: This article explores where and how silence ‘takes place’. After reviewing various cultural and political meanings and performances of silence, this article will provide an in-depth analysis of the Norwegian pavilion at the universal exhibition Expo 2000 in Hanover. While most pavilions at this exhibition displayed objects about nature, technology and humankind – the general theme of Expo 2000 – the main attraction of the Norwegian pavilion was an art installation named ‘The Silent Room’ produced by a contemporary artist. This article describes how the Silent Room was constructed, how the silence therein was technologically produced and how it was experienced by some of its visitors. Several technologies were used to create silence: a waterfall outside of the pavilion and a sound installation and isolating material inside. On one hand, technology was used indirectly, to produce the opposite of silence (sound) and to create the possibility of silence. On the other hand, a direct relationship between silenc...