31 research outputs found

    Іншомовні аспекти фахової між культурної комунікації в сучасній вітчизняній і зарубіжній науковій літературі

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    У статті розглядаються основні напрямки сучасних вітчизняних і зарубіжних наукових досліджень з іншомовної фахової міжкультурної комунікації. Aspects of the professional foreign language of intercultural communication in modern domestic and foreign scientific literature. The paper discusses the main directions of current domestic and foreign scientific research in the field of professional foreign language intercultural communication

    Acting on a visual world: The role of perception in multimodal HCI

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    Following the ecological approach to visual perception, this paper investigates multimodal referring acts in Human-Computer Interaction. Preliminary results from a simulation experiment allow to: (a) clarify the effect perceptual organization on multimodal communication; (b) provide guidelines for designing effective multimodal interfaces. Demonstrating that both the verbal and the gestural part of a referential act are influenced by perception, we confirm the need and the utility of taking into account perceptual organization to analyze referential expressions in a more robust way. As a conclusion, we show how these results can lead to an actual implementation of a gesture interpretation module directed by the reference analysis process

    Aqueous alteration of silicate glass: State of knowledge and perspectives

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    International audienceThe question of silicate glass chemical durability is at the heart of many industrial and environmental issues, with certain glasses, such as bioglasses, needing to transform rapidly, while others, like nuclear glasses, extremely slowly. Due to the wide diversity of the chemical composition for these types of materials and their metastability – no thermodynamic equilibrium can be reached between glass and solution – the evaluation of chemical durability remains a scientific challenge. In this article, we review the current state of knowledge on glass alteration mechanisms and kinetics, and point to some perspectives for glasses for which no direct experimental validation is currently possible. Thanks to the development of novel techniques and international collaborations, a better understanding of the mechanisms involved has been achieved. Mechanistic models have been developed at some specific scales, although holistic models still need further development to link the various scales and perform reliable predictions

    DOWNSCALING PROCEDURE FOR CONVECTIVE HEAT TRANSFER IN PERIODIC POROUS MEDIA

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    International audienceThis study proposes a downscaling methodology consisting of describing the convective heat transfer at the pore scale of the porous media from the knowledge of the velocity and temperature fields at the Darcy scale. The analysis is based on the derivation of local deviation equations on a local unit cell. A penalization technique is used to deal with the macroscopic source terms involved in these equations. The partial differential equations system is closed assuming periodic conditions at the boundaries of the unit cell. Numerical simulations illustrate the relevance and the limitations of the downscaling procedure applied to two-dimensional periodic arrays of cylinders

    Influence of temperature and relative humidity on vapor hydration of an AVM nuclear waste glass

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    International audience• The vapor hydration rate, calculated from the thickness of the homogeneous altered layer, follows Arrhenius law for temperature dependence between the temperature range 50°C-90°C. • Network-hydrolysis is the predominant rate controlling mechanism for the studied duration. • Nature/identity of secondary phases vary as function of both temperature and relative humidity and the nature of the altered surface varies as a function of relative humidity. • XRD patterns indicated the presence of precipitates containing rare-earth elements and transition metals only on the samples altered at lower relative humidity values (50% and 76%)

    Insight into sodium silicate glass structural organization by multinuclear NMR combined with first-principles calculations

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    International audienceShort and medium range order of silica and sodium silicate glasses have been investigated from a quantitative analysis of 29Si MAS NMR and 23Na, 17O MQMAS NMR spectra. The method described enables the extraction of the underlying 17O NMR parameter distributions of bridging oxygens (BOs) and non-bridging oxygens (NBOs), and yields site populations which are confirmed by 29Si NMR data. The extracted NMR parameter distributions and their variations with respect to the glass chemical composition can then be analyzed in terms of local structural features (bond angles and bond lengths, coordination numbers) with the help of molecular dynamics simulations combined with first-principles calculations of NMR parameters. Correlations of relevant structural parameters with 23Na, 29Si and 17O NMR interactions (isotropic chemical shift δiso, quadrupolar coupling constant CQ and quadrupolar asymmetry parameter ηQ) are re-examined and their applicability is discussed. These data offer better insights into the structural organization of the glass network, including both chemical and topological disorder. Adding sodium to pure silica significantly diminishes the Si-O-Si bond angles and leads to a longer mean Si-O bond length with a slight decrease of the mean Na-O bond length. Moreover, the present data are in favor of a homogeneous distribution of Na around both oxygen species in the silicate network. Finally, our approach was found to be sensitive enough to investigate the effect of addition of a small quantity of molybdenum oxide (about 1 mol%) on the 17O MAS spectrum, opening new possibilities for investigating the Mo environment in silicate glasses

    STRUCTURE AND CHEMICAL DURABILITY OF LEAD CRYSTAL GLASS

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    International audienceSilicate glasses containing lead, also called lead crystal glasses, are commonly used as food product containers, in particular for alcoholic beverages. Lead’s health hazards require major attention, which can first be investigated through the understanding of Pb release mechanisms in solution. The behavior of a commercial crystal glass containing 10.6 mol per cent of PbO (28.3 wt per cent) was studied in a reference solution of 4 per cent acetic acid at 22, 40, and 70C at early and advanced stages of reaction. High-resolution solid-state 17O and 29Si NMR was used to probe the local structure of the pristine and, for the first time, of the altered lead crystal glass. Inserted into the vitreous structure between the network formers as Si–O–Pb bonds, Pb does not form Pb–O–Pb clusters which are expected to be more easily leached. A part of K is located near Pb, forming mixed Si–O–(Pb,K) near the nonbridging oxygens. Pb is always released into the solution following a diffusion-controlled dissolution over various periods of time, at a rate between 1 and 2 orders of magnitude lower than the alkalis (K and Na). The preferential release of alkalis is followed by an in situ repolymerization of the silicate network. Pb is only depleted in the outermost part of the alteration layer. In the remaining part, it stays mainly surrounded by Si in a stable structural configuration similar to that of the pristine glass. A simple model is proposed to estimate the Pb concentration as a function of glass surface, solution volume, temperature, and contact time
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