Conservatoire national des arts et métiers

About: Conservatoire national des arts et métiers is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Context (language use). The organization has 3573 authors who have published 7127 publications receiving 141430 citations. The organization is also known as: CNAM & Conservatoire des arts et métiers.

Finite element formulation of viscoelastic sandwich beams using fractional derivative operators

Abstract: This paper presents a finite element formulation for transient dynamic analysis of sandwich beams with embedded viscoelastic material using fractional derivative constitutive equations. The sandwich configuration is composed of a viscoelastic core (based on Timoshenko theory) sandwiched between elastic faces (based on Euler– Bernoulli assumptions). The viscoelastic model used to describe the behavior of the core is a four-parameter fractional derivative model. Concerning the parameter identification, a strategy to estimate the fractional order of the time derivative and the relaxation time is outlined. Curve-fitting aspects are focused, showing a good agreement with experimental data. In order to implement the viscoelastic model into the finite element formulation, the Grunwald definition of the fractional operator is employed. To solve the equation of motion, a direct time integration method based on the implicit Newmark scheme is used. One of the particularities of the proposed algorithm lies in the storage of displacement history only, reducing considerably the numerical efforts related to the non-locality of fractional operators. After validations, numerical applications are presented in order to analyze truncation effects (fading memory phenomena) and solution convergence aspects.

A Brief History of Fluorescence and Phosphorescence before the Emergence of Quantum Theory

Abstract: Fluorescence and phosphorescence are two forms of photoluminescence used in modern research and in practical applications The early observations of these phenomena, before the emergence of quantum theory, highlight the investigation into the mechanism of light emission In contrast to incandescence, photoluminescence does not require high temperatures and does not usually produce noticeable heat Such a “cold light” was the object of an interesting controversy in the 19th century: does it fit into thermodynamics? The early applications, such as the fluorescent tube, fluorescence analysis, and fluorescent tracers, are described

Life cycle analysis of 4.5 MW and 250 W wind turbines

Abstract: Electric generation by wind turbine is growing very strongly. However, the environmental impact of wind energy is still a matter of controversy. This paper uses Life Cycle Assessment, comparing two systems: a 4.5 MW and a 250 W wind turbines, to evaluate their environmental impact. All stages of life cycle (manufacturing, transports, installation, maintenance, disassembly and disposal) have been analysed and sensitivity tests have been performed. According to the indexes (PEPBT (primary energy pay back time), CO2 emissions, etc.), the results show that wind energy is an excellent environmental solution provided first, the turbines are high efficiency ones and implemented on sites where the wind resource is good, second, components transportation should not spend too much energy and, third, recycling during decommissioning should be performed correctly. This study proves that wind energy should become one of the best ways to mitigate climate change and to provide electricity in rural zones not connected to the grid.

Clinical characteristics of a series of 302 French patients with hidradenitis suppurativa, with an analysis of factors associated with disease severity.

Abstract: Background Factors associated with the severity of hidradenitis suppurativa (HS) are not known. Objective We sought to identify factors associated with the severity of HS. Methodology The severity of disease in a series of 302 consecutive patients with HS was assessed using the Sartorius score. Results Atypical locations were more common in men than in women (47.1% vs 14.8%; P Limitations The referral center base of the study may have biased recruitment. Conclusion Our data showed a significant association between the severity of HS and several clinical and behavioral factors. Prospective studies are needed to confirm the prognostic role of these factors.