Détermination de la granulométrie des aérosols dans les émissions canalisées : cas d'une cimenterie

National audienceMonitoring emissions of particles with a diameter smaller than 10 um (PM10) has become of growing interest. However, measuring such particles is rather difficult, it appears as a result necessary to develop and assess measurement methods for the monitoring of PM10 from stack and fugitive emissions. The aim of the GAEC program [Granulometrie des Aerosols dans les Emissions Canalisees : Aerosol size distribution from stack emissions] is double : developing monitoring methods and improving knowledge on fine particulate stack emissions. Three institutes are involved in the program : Sechaud Environnement (formerly LECES), INERIS and CERTAM. This paper concems the results obtained from the first two steps of the program: a state of the art of the available techniques, the evaluation of the selected techniques during a sampling campaign at a cement plant.Face à l'intérêt grandissant concernant les émissions de particules de diamètre inférieur à 10 um et aux difficultés rencontrées lors de la mesure de ces particules, des développements métrologiques et l'évaluation des méthodes de mesurage en émissions canalisées et diffuses sont nécessaires. Le projet GAEC [Granulométrie des Aérosols dans les Emissions Canalisées] s'inscrit dans ce double contexte de développement métrologique et d'amélioration, des connaissances sur les sources d'émission de particules fines. Il porte plus précisément sur la "Détermination de la granulométrie des aérosols dans les émissions industrielles canalisées : PM10, PM(2,5), PM(1), et PM(0,1)". Il réunit trois partenaires : Séchaud Environnement (anciennement LECES), INERIS et CERTAM. L'intervention proposée ici a pour objectif de rapporter les résultats obtenus lors des deux premières phases du projet, à savoir : une étude bibliographique de l'état de l'art sur les techniques de mesure disponibles,la mise en oeuvre des techniques retenues lors d'une campagne de mesure menée sur une cimenterie

Analytic Metaphysics versus Naturalized Metaphysics: The Relevance of Applied Ontology

The relevance of analytic metaphysics has come under criticism: Ladyman & Ross, for instance, have suggested do discontinue the field. French & McKenzie have argued in defense of analytic metaphysics that it develops tools that could turn out to be useful for philosophy of physics. In this article, we show first that this heuristic defense of metaphysics can be extended to the scientific field of applied ontology, which uses constructs from analytic metaphysics. Second, we elaborate on a parallel by French & McKenzie between mathematics and metaphysics to show that the whole field of analytic metaphysics, being useful not only for philosophy but also for science, should continue to exist as a largely autonomous field

Specific anchoring modes of two distinct dystrophin rod sub-domains interacting in phospholipid Langmuir films studied by atomic force microscopy and PM-IRRAS.

International audienceDystrophin rod repeats 1-3 sub-domain binds to acidic phosphatidylserine in a small vesicle binding assay, while the repeats 20-24 sub-domain does not. In the present work, we studied the adsorption behaviour of both sub-domains at the air/liquid interface and at the air/lipid interface in a Langmuir trough in order to highlight differences in interfacial properties. The adsorption behaviour of the two proteins at the air/liquid interface shows that they display surface activity while maintaining their alpha-helical secondary structure as shown by PM-IRRAS. Strikingly, R20-24 needs to be highly hydrated even at the interface, while this is not the case for R1-3, indicating that the surface activity is dramatically higher for R1-3 than R20-24. Surface-pressure measurements, atomic force microscopy and PM-IRRAS are used in a Langmuir experiment with DOPC-DOPS monolayers at two different surface pressures, 20mN/m and 30mN/m. At the lower surface pressure, the proteins are adsorbed at the lipid film interface while maintaining its alpha-helical structure. After an increase of the surface pressure, R1-3 subsequently produces a stable film, while R20-24 induces a reorganization of the lipid film with a subsequent decrease of the surface pressure close to the initial value. AFM and PM-IRRAS show that R1-3 is present in high amounts at the interface, being arranged in clusters representing 3.3% of the surface at low pressure. By contrast, R20-24 is present at the interface in small amounts bound only by a few electrostatic residues to the lipid film while the major part of the molecule remains floating in the sub-phase. Then for R1-3, the electrostatic interaction between the proteins and the film is enhanced by hydrophobic interactions. At higher surface pressure, the number of protein clusters increases and becomes closer in both cases implying the electrostatic character of the binding. These results indicate that even if the repeats exhibit large structural similarities, their interfacial properties are highly contrasted by their differential anchor mode in the membrane. Our work provides strong support for distinct physiological roles for the spectrin-like repeats and may partly explain the effects of therapeutic replacement of dystrophin deficiency by minidystrophins

Duality and ontology

A ‘duality’ is a formal mapping between the spaces of solutions of two empirically equivalent theories. In recent times, dualities have been found to be pervasive in string theory and quantum field theory. Naïvely interpreted, duality-related theories appear to make very different ontological claims about the world—differing in e.g. space-time structure, fundamental ontology, and mereological structure. In light of this, duality-related theories raise questions familiar from discussions of underdetermination in the philosophy of science: in the presence of dual theories, what is one to say about the ontology of the world? In this paper, we undertake a comprehensive and non-technical survey of the landscape of possible ontological interpretations of duality-related theories. We provide a significantly enriched and clarified taxonomy of options—several of which are novel to the literature

Estimation of Fiber Orientations Using Neighborhood Information

Data from diffusion magnetic resonance imaging (dMRI) can be used to reconstruct fiber tracts, for example, in muscle and white matter. Estimation of fiber orientations (FOs) is a crucial step in the reconstruction process and these estimates can be corrupted by noise. In this paper, a new method called Fiber Orientation Reconstruction using Neighborhood Information (FORNI) is described and shown to reduce the effects of noise and improve FO estimation performance by incorporating spatial consistency. FORNI uses a fixed tensor basis to model the diffusion weighted signals, which has the advantage of providing an explicit relationship between the basis vectors and the FOs. FO spatial coherence is encouraged using weighted l1-norm regularization terms, which contain the interaction of directional information between neighbor voxels. Data fidelity is encouraged using a squared error between the observed and reconstructed diffusion weighted signals. After appropriate weighting of these competing objectives, the resulting objective function is minimized using a block coordinate descent algorithm, and a straightforward parallelization strategy is used to speed up processing. Experiments were performed on a digital crossing phantom, ex vivo tongue dMRI data, and in vivo brain dMRI data for both qualitative and quantitative evaluation. The results demonstrate that FORNI improves the quality of FO estimation over other state of the art algorithms.Comment: Journal paper accepted in Medical Image Analysis. 35 pages and 16 figure

Preoperative left ventricular ejection fraction and left atrium reverse remodeling after mitral regurgitation surgery

Background: Left atrium enlargement has been associated with cardiac events in patients with mitral regurgitation (MR). Left atrium reverse remodeling (LARR) occur after surgical correction of MR, but the preoperative predictors of this phenomenon are not well known. It is therefore important to identify preoperative predictors for postoperative LARR.Methods: We enrolled 62 patients with chronic severe MR (prolapse or flail leaflet) who underwent successful mitral valve surgery (repair or replacement); all with pre-and postoperative echocardiography. LARR was defined as a reduction in left atrium volume index (LAVI) of >= 25%. Stepwise multiple regression analysis was used to identify independent predictors of LARR.Results: LARR occurred in 46 patients (74.2%), with the mean LAVI decreasing from 85.5 mL/m(2) to 49.7 mL/m(2) (p = 25% with a sensitivity of 71.7% and a specificity of 56.3%.Conclusions: LARR occurs frequently after mitral valve surgery and is associated with preoperative LVEF higher than 63.5%.Inst Dante Pazzanese Cardiol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, BrazilDisciplina Cardiol, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, BrazilWeb of Scienc

Détection de particules micrométriques en suspension dans l'air par technique LIBS (Laser-Induced Breakdown Spectroscopy)

International audienceLes aérosols peuvent être définis comme des particules solides ou liquides en suspension dans un gaz avec des diamètres s'échelonnant du nanomètre jusqu'à plusieurs micromètres. La génération d'aérosols dans les procédés industriels peut représenter une menace pour les travailleurs comme pour l'environnement. La possible émission, sous forme de particules de tailles micrométriques/submicroniques, de métaux lourds issus des rejets canalisés d'industries (telles que les fonderies ou les incinérateurs) ou bien encore de pelotes de nanotubes de carbone sur leur lieu de production, en sont deux exemples. Les rejets de métaux lourds dans l'atmosphère sont essentiellement d'origine anthropique et produits par des industries impliquant notamment des procédés de combustion comme les incinérateurs et les fonderies. Compte tenu des effets nocifs avérés des métaux lourds sur l'homme et l'environnement, les rejets sont encadrés par des réglementations (arrêtés du 02 février 1998 et du 20 septembre 2002). L'évolution de celles-ci, toujours plus stricte, nécessite le développement d'outils adaptés et notamment, d'une instrumentation de terrain permettant l'analyse in-situ en automatique avec une résolution temporelle adéquate. Les travaux présentés ici sont focalisés sur la quantification en temps réel de la fraction particulaire dans une gamme de tailles s'échelonnant de 1 à 10 µm. Depuis leur découverte, les nanotubes de carbone (NTC) suscitent un intérêt croissant eu égard aux très nombreuses applications possibles dans de nombreux domaines industriels. Les nombreuses applications potentielles des NTC soulèvent l'enthousiasme mais également des inquiétudes. Les possible effets que pourraient avoir les NTC sur la santé humaine sont très mal connus et les recherches sur ces sujets toujours en cours. Leur morphologie en forme de fibre est inquiétante car elle rappelle celle de l'amiante. Au risque lié à la morphologie des NTC s'ajoute celui de la toxicité chimique des éléments contenus dans les nanotubes de carbone, souvent des éléments de catalyse. Sur les lieux de production, la voie aérienne est la source la plus probable de contamination. Bien que les procédés de production soient sécurisés, une possible fuite n'est jamais à écarter. De plus, le risque d'exposition existe à plusieurs étapes de production, tels que le conditionnement du produit final par exemple. Il est donc nécessaire de disposer d'outils de terrain permettant d'accéder à la taille et à la morphologie mais aussi à la composition chimique des particules émises. Il existe à l'heure actuelle peu d'instruments permettant, in-situ et en temps réel, de détecter l'émission de particules et de mesurer les concentrations émises selon leur nature chimique élémentaire. La technique LIBS (Laser-Induced Breakdown Spectroscopy) ou spectroscopie de plasma induit par laser semble adaptée à une telle problématique. C'est pourquoi elle a été appliquée dans les deux cas susmentionné

Monitoring of ultrafine particles in French regional air quality network

Monitoring of ultrafine particles (UFP) in the ambient air is ongoing since 2012 in France. A national working group was created in 2014, including nowadays five French regional air quality monitoring networks. The main instrument selected to monitor UFP is the particle sizer “UFP-3031” (TSI Inc.). It measures the particle number concentration between 20 and 800 nm with six size channels. Two intercomparisons were organized in 2014 and 2015, which evaluated the accuracy of this instrument through a comparison with other techniques (such as Scanning Mobility Particle Sizer, SMPS), and through uncertainty calculations. Recently, several networks have been also equipped with CPC (condensation particle counter) to be able to measure the total UFP number concentration from 7 nm. This work presents the main results of short and long-term measurement of UFP which have been carried out in various environments: urban/traffic sites, near heavy industry zones (Dunkerque and Fos-sur-Mer in northern and southern France, respectively), near harbor area (Nice)… For urban/ traffic environment, the number concentration and size distribution are compared at the national level; it appears that they vary significantly depending on the influence of road traffic around the site. The concentration levels near traffic sites are at least twice than in the urban area, especially for UFP smaller than 50 nm. Additionally, the UFP measurement also makes it possible to improve the identification of specific sources and to understand the atmospheric physicochemical phenomena. The relationship between UFP and industrial emissions, ferries, forest fires was clearly identified in different places in France. During summer, the UFP monitoring also shows the formation of new particles (between 20-30 nm or smaller) in the afternoon, due to photochemical reactions. From 2019, the French national strategy on UFP will start putting a particular emphasis on the impact of UFP on human health

Evaluation of soil solar heating for control of damping-off fungi in two forest nurseries in France

Field experiments were carried out at two different forest nurseries during the summer of 1994 to examine the efficacy of soil solarization for the control of damping-off. Both soils hosted Pythium spp., Fusarium spp. and Rhizoctonia solani as damping-off agents. Soil samples from solarized, steamed, fumigated and untreated plots were periodically collected and assayed for soil infectivity. Solarization with a double layer of polyethylene film was as effective as steaming or fumigation in reducing soil infectivity in the uppermost layer. During July the temperature of covered beds rose as high as 50°C at a soil depth of 5cm. The method achieved good control of Pythium spp., the main cause of damping-off at both nurseries, whereas Fusarium spp. were more tolerant. The association of Trichoderma spp. with a reduction of soil infectivity at the last sampling date strongly suggested that biocontrol processes were induced after solarization. Soil solarization provides a suitable method for control of damping-off.Facultad de Ciencias Agrarias y Forestale