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.

A Performance Evaluation of Spatial Join Processing Strategies

Abstract: We provide an evaluation of query execution plans (QEP) in the case of queries with one or two spatial joins. The QEPs assume R*-tree indexed relations and use a common set of spatial joins algorithms, among which one is a novel extension of a strategy based on an on-the-fly index creation prior to the join with another indexed relation. A common platform is used on which a set of spatial access methods and join algorithms are available. The QEPs are implemented with a general iterator-based spatial query processor, allowing for pipelined QEP execution, thus minimizing memory space required for intermediate results.

A Review on Fluid-induced Flag Vibrations

Abstract: Fluid-induced flag vibrations provide unattended, efficient, low-cost, and scalable solutions for energy harvesting to power distributed wireless sensor nodes, heat transfer enhancement in channel flow, and mixing enhancement in process industries. This review surveys three generic configurations, the inverted flag, the standard flag, and the forced flag, i.e., an inverted or standard flag located downstream of a bluff body. Their instability boundaries, vibration dynamics, and vortex dynamics are compared in a unified framework to elucidate their common and distinct features and provide insights into the design of vibrating flags for various applications. Some common features are also identified and analyzed for describing the interaction between multiple flags, three-dimensional (3D) effects, and Reynolds number effects. The suggestions are intended to guide future research directions.

New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas

Abstract: The SI unit of temperature will soon be redefined in terms of a fixed value of the Boltzmann constant k derived from an ensemble of measurements worldwide. We report on a new determination of k using acoustic thermometry of helium-4 gas in a 3-litre volume quasi-spherical resonator. The method is based on the accurate determine of acoustic and microwave resonances to measure the speed of sound at different pressures. We find for the universal gas constant R = 8.31 44614 (50) Jmol-1K-1. Using the current best available value of the Avogadro constant, we obtain k = 1.38 064 878(83) ×10^(23) JK-1 with u(k) / k = 0.60 x 10^(-6), where the uncertainty u is one standard uncertainty corresponding to a 68 % confidence level. This value is consistent with previous determinations and with that of the 2014 CODATA adjustment of the fundamental constants (Mohr et al., Rev. Mod. Phys. 88, 035009 (2016)), within the standard uncertainties. We combined the present values of k and u(k) with earlier values that were measured at LNE. Assuming the maximum possible correlations between the measurements, (klsubgpresentl/subg/〈k〉-1) = 0.071×10lsupg-6l/supg and the combined ur(k) is reduced to 0.56×10lsupg-6l/supg. Assuming minimum correlations, (klsubgpresentl/subg/〈k〉-1) = 0.10×10lsupg-6l/supg and the combined ur(k) is reduced to 0.49×10lsupg-6l/supg.