Contribution à la modélisation du comportement chimique des aérosols issus d'un feu de sodium par le modèle d'absorption réactive

National audienceThe use of liquid sodium, as a coolant in Sodium cooled Fast Reactors (SFR) circuits, requires studyingthe consequences of a sodium fire for safety analysis, and particularly the toxicological impact of sodiumfire aerosols. More particularly, the carbonation of sodium fire aerosols from sodium hydroxide (NaOH)to sodium carbonate (Na$_2$CO$_3$) is investigated.A new kinetic model based on the CO$_2$ reactive absorption, and the two-film theory was developed todescribe the carbonation process of NaOH solutions, in order to take into account the NaOH aerosols’initial characteristics in equilibrium with the atmosphere. This model was applied for the case of NaOHaerosols, considering the CO$_2$ absorption at the particle external surface. By comparisons withexperimental data, the model was validated over the range studied of relative humidity and initial particlediameter. However, the values of the interfacial area need to be consolidated and justified. The modellingvalidation needs also to be completed, looking forward the next experimental data.Dans le cadre du développement des réacteurs nucléaires à neutrons rapides, refroidis au sodium, desétudes sont menées sur les conséquences de feu de sodium et en particulier sur l'impact toxicologique desaérosols lors de leur éventuelle dispersion atmosphérique. Et plus spécifiquement, la carbonatationd’aérosols issus de feu de sodium à partir d'hydroxyde de sodium (NaOH) en carbonate de sodium(Na$_2$CO$_3$) est étudiée.Un nouveau modèle cinétique basé sur l'absorption réactive de CO$_2$ et sur la théorie du double film a étédéveloppé pour décrire le processus de carbonatation de solution de NaOH, afin de prendre en compte lescaractéristiques initiales des aérosols de NaOH en équilibre avec l'atmosphère. Ce modèle a été appliquédans le cas des aérosols de soude, en considérant l'absorption du CO$_2$ à la surface externe des particules.Par comparaison avec les données expérimentales, le modèle a été validé dans la plage étudiée d'humiditérelative et de diamètre de particule initial. Toutefois, les valeurs du taux de surface accessible doivent êtreconsolidées et justifiées. La validation de la modélisation doit également être complétée à l’aide deprochaines données expérimentales

Invasion biology of spotted wing Drosophila (Drosophila suzukii): a global perspective and future priorities

The Asian vinegar fly Drosophila suzukii (spotted wing Drosophila [SWD]) has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, we explore common themes in the invasion biology of SWD by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. We conclude that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capabilities; as well as applied studies of alternative, cost-effective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful strategies and insights gained from various geographic regions

Analysis of the invasiveness of spotted wing Drosophila (Drosophila suzukii) in North America, Europe, and the Mediterranean Basin

The polyphagous Asian vinegar fly Drosophila suzukii (spotted wing Drosophila) is a native of Eastern and Southeastern Asia. It emerged as an important invasive insect pest of berries and stone fruits in the Americas and Europe beginning in 2008. Species distribution models are commonly used for analyzing the extant and potential range expansion of invasive species. Previous modeling efforts for D. suzukii include a degree-day model, a MaxEnt ecological niche model, a demographic model incorporating the effects of temperature, and a preliminary mechanistic physiologically-based demographic model (PBDM). In the present analysis, we refine the PBDM for D. suzukii based on biological data reported in the literature. The PBDM is used to assess the effects of temperature and relative humidity from a recently published global climate dataset (AgMERRA) on the prospective geographic distribution and relative abundance of the pest in the USA and Mexico, and in Europe and the Mediterranean Basin. Our focus is on areas of recent invasion and of predicted higher invasiveness in these areas. Although the species is native to Asia and is of putative temperate origins, it has established in subtropical to north temperate zones worldwide where it infests a wide range of wild and domesticated berries and stone fruits. The model captures the observed phenology of D. suzukii at specific locations, as well as the potential geographic distribution and relative favorability across larger regions. The main limiting factor is cold winter temperature in northern areas, though high temperatures and low relative humidity may be limiting in arid areas. The effect of greater cold tolerance in winter morph adults is explored