Search results for "Process"
showing 10 items of 22310 documents
Adopting magnetocaloric heat pumping and refrigeration for electrical vehicle
2017
International audience; Refrigeration process is based on conventional gas compression and expansion techniques. However, this technique has numerous disadvantages since it generates greenhouse gas and is partly responsible for global warming. This paper exposes analternative method: magnetocaloric refrigeration that presents the advantage to combine high-energy efficiency and respect of theenvironment. Magnetic heat pumping and cooling is compared to conventional method applied on vehicle air conditioning system.Simulation results are used to demonstrate the approach.
Synthesis and characterisation of pack cemented aluminide coatings on metals
2004
Abstract The exposition of metallic materials to high temperature environments leads to their corrosion because of oxidation or sulphidation. One way to protect such materials is to produce an Al 2 O 3 layer which needs to be continuous enough to limit diffusion of oxygen or metallic elements, and withstand this corrosion. Since a few years, it has been proved that aluminide compounds are one of the most effective materials to achieve this goal. Indeed, they possess sufficient Al and many beneficial mechanical properties when exposed to high temperature conditions to make possible the formation of a protective Al 2 O 3 scale. This study is aimed at the elaboration of iron, nickel and molybd…
Material Substitution for Automotive Applications: A Comparative Life Cycle Analysis
2012
Lightweight materials have become an important strategy in the automotive industry to enable vehicle weight reduction and reduce fuel consumption. However, when developing specific strategies, the overall benefits of any material should be analyzed throughout its life cycle to comprehend energy/environmental differences that arise during its processing and its final use. A key example is aluminum which despite having great potential in the use phase requires large amounts of energy to process. This paper provides a comparison between aluminum and steel utilizing a life-cycle approach. This approach reveals the importance of incorporating a recycling strategy to leverage aluminum’s low-weigh…
Multi-sensor Fusion through Adaptive Bayesian Networks
2011
Common sensory devices for measuring environmental data are typically heterogeneous, and present strict energy constraints; moreover, they are likely affected by noise, and their behavior may vary across time. Bayesian Networks constitute a suitable tool for pre-processing such data before performing more refined artificial reasoning; the approach proposed here aims at obtaining the best trade-off between performance and cost, by adapting the operating mode of the underlying sensory devices. Moreover, self-configuration of the nodes providing the evidence to the Bayesian network is carried out by means of an on-line multi-objective optimization.
Sign Languages Recognition Based on Neural Network Architecture
2017
In the last years, many steps forward have been made in speech and natural languages recognition and were developed many virtual assistants such as Apple’s Siri, Google Now and Microsoft Cortana. Unfortunately, not everyone can use voice to communicate to other people and digital devices. Our system is a first step for extending the possibility of using virtual assistants to speech impaired people by providing an artificial sign languages recognition based on neural network architecture.
Thermochemical properties of small open-shell systems: experimental and high-levelab initioresults for NH2and
2006
The first adiabatic ionization energy and the first singlet–triplet splitting of the amidogen radical (NH2) have been determined by high-level ab initio quantum chemistry based on the coupled-cluster approach (90 041 and 10 319 cm−1, respectively) and by high-resolution pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectroscopy (90 083.8 ± 1.0 and 10 222.0 ± 1.3 cm−1, respectively). A comparison between the theoretical and experimental values demonstrates the predictive powers of high-level ab initio theory in the derivation of the thermochemical properties of small molecular systems. The absolute accuracy of better than 100 cm−1 alleviates the experimental search for…
Ammonia Synthesis: State of the Bellwether Reaction
2013
Catalytic ammonia synthesis has been judged to be one of mankind's greatest scientific achievements during the twentieth century. The socioeconomic implications of producing ammonia industrially have been a strong driving force, and this development has spurred a range of new discoveries within physics, chemistry, and chemical engineering. In this chapter, we describe how it has been possible in recent years to provide a full understanding of the catalytic ammonia synthesis reaction at the atomic level through the combined use of experiments and quantum mechanical electronic structure calculations, thus clearly showing many of the reasons why ammonia synthesis has been, and still is, the be…
Endemism as a palaeobiogeographic parameter of basin history illustrated by early- and mid-Liassic peri-Tethyan ammonite faunas
2002
Abstract Episodes of endemism during Sinemurian–Pliensbachian times are described from synthetic data (publications and unpublished collections) about ammonite faunas of the western reaches of the Tethys. The Lusitanian, Sub-Betic and High Atlas basins receive special attention. The study shows that (1) endemism occurs principally in the Lusitanian and High Atlas basins, which are the most confined palaeogeographic structures; (2) it tends to occur synchronously in different basins but involving different taxa, i.e. it is independent of phylogeny; (3) it is not obviously correlated with relative sea-level at any given time. However, the fact that episodes of endemism coincide with second-or…
Distribution of clay minerals in Early Jurassic Peritethyan seas: palaeoclimatic significance inferred from multiproxy comparisons.
2009
13 pages; International audience; A set of published, unpublished, and new clay mineral data from 60 European and Mediterranean localities allows us to test the reliability of clay minerals as palaeoclimatic proxies for the Pliensbachian–Toarcian period (Early Jurassic) by reconstructing spatial and temporal variations of detrital fluxes at the ammonite biochronozone resolution. In order to discuss their palaeoclimatic meaning, a compilation of low-latitude belemnite δ18O, δ13C, Mg/Ca, and 87Sr/86Sr values is presented for the first time for the whole Pliensbachian– Toarcian period. Once diagenetic and authigenic biases have been identified and ruled out, kaolinite content variation is cons…
Episodic deposition of the Lias in the Medianes nappe (western Switzerland): a record from mineralized ammonite-bearing beds
1992
Abstract Sinemurian and Pliensbachian depositional sequences from the starved distal northern continental margin of the Tethys are preserved in the Medianes Nappe (Western Swiss Prealps). They contain mineralized beds which include a variety of facies. The northern continental margin of the Tethys was broken into blocks, less than 50 km wide, during an extensional phase. The Sinemurian and Pliensbachian sediments in the study are vary in thickness from less than 50 m in the north to more than 200 m in the south. Although the upper Sinemurian to Pliensbachian mineralized beds are thin, between 0.10 and 0.50 m thick, they commonly contain several distinct faunal horizons stacked one upon anot…