Faune stygobie du Sud de l'Anti-Atlas marocain premiers résultats

Ce travail présente tes premières données sur la faune aquatique souterraine du Sud de l'Anti-Atlas marocain. Dans cette zone au climat semi-continental de type saharien à hiver tempéré, plus de 50 stations ont été prospectées, puits, sources et milieux hyporhéiques des oueds. 7 puits et 2 sources de la région de Guelmim, choisis en raison de leur intérêt stygobiologique, font l'objet d'une étude suivie pendant 2 ans, d'un point de vue faunistique et écologique. Ces stations sont brièvement décrites (localisation géographique et topographique, hydrogéologie, physico-chimie de l'eau), de même que leurs biocénoses. 59 taxons, dont 11 sont considérés comme des espèces stygobies, ont été récoltés dans les eaux souterraines, interstitiettes ou karstiques. L'étude porté plus particulièrement sur les Crustacés Péracarides : Thermosbénacés, Amphiphodes Métacrangonyctidés, Isopodes Cirolanidés et Stenaseltidés. Des remarques sur l'écologie de ces espèces ainsi que des hypothèses patéobiogéographiques sont présentées.The first data recorded on the aquatic underground fauna of the South Moroccan Anti-Atlas are reported. More than 50 biotopes, wells, springs and river underflows, have been prospected in this Saharian province with a semi-continental climate. The fauna and ecology of seven wells and two springs, stygobiologically interesting, have been regularly investigated for two years. These nine stations are described briefly (geographic and topographic location, hydrogeology and physicochemical characteristics of the water) as well as their zoocenoses. The fauna of interstitial and karstic waters includes 59 taxa, 11 of which are stygobiontic. The study is focused mainly on the Peracarid Crustacea : Thermosbaenacea, Amphipoda Metacrangonyctidae, Isopoda Cirolanidae and Stenasellidae. Some remarks are added on the ecology of these species and a paleobiogeographic hypothesis is proposed

L'assainissement non collectif en France : Analyse statistique de la qualité des eaux usées traitées de 240 installations

S2SMALL, Nantes, FRA, 23-/10/2017 - 26/10/2017International audienceAn assessment of on-site sanitation systems began in 2011 to evaluate their efficiency. Data were collected from 240 on-site sanitation facilities in 22 French departments which cover 5 of the 6 Water Agency territories. The parameters analysed at the outlet are TSS, COD, BOD 5 , NH 4 + -N, NO 3 - -N and TKN. The aim of this article is to describe the outlet effluent quality and explain the data dispersion by analyzing the impact of explanatory variables such as i) the sampling method, ii) the treatment processes, iii) the applied organic load, iv) the aging and v) the maintenance

Photophysical Studies of Photon Upconversion via Triplet-Triplet Annihilation in Polymer Systems with Potential Photovoltaic Applications

The present work reports the study of noncoherent photon upconversion (NCPU) via triplet-triplet annihilation (TTA) in polymer systems. This upconversion mechanism has application in photovoltaic devices through the utilization of sub-band gap photons for potentially enhanced power conversion efficiencies. First, homomolecular TTA was studied in zinc tetraphenylporphyrin (ZnTPP) in polymer matrices. Here, ZnTPP acts as both the sensitizer and upconverting emitter as TTA yields an S2 excited porphyrin. Use of poly(methyl methacrylate) (PMMA) as the host polymer demonstrates aggregation-driven upconverted fluorescence (UC) by TTA (TTA-UC). The dye-loading ratio of the precursor solution was varied, controlling the degree of pre-aggregation. Power-dependence studies of the champion film demonstrated that TTA-UC is occurring toward the strong annihilation kinetic limit. A sub-linear dependence of upconverted fluorescence on film thickness was observed in this system. The ZnTPP study was extended to polymers possessing low glass transition temperatures, representing molecular diffusion-driven TTA-UC. Upconverted fluorescence was not observed in ZnTPP in a polyurethane (PU) matrix, likely due to coordination of the PU to the axial position of the Zn2+ ion. Low intensity NCPU via homomolecular TTA was observed in ZnTPP in a poly(ethylene glycol) (PEG) matrix, but the kinetic limit was not determined due to film photodegradation. Dye-loading studies revealed that porphyrin self-quenching was evident at low dye concentrations. Likely reasons for the low upconverted fluorescence intensities realized are this self-quenching and the possibility of PEG coordination to the Zn2+ ion, though it is believed self-quenching is the dominant parasitic effect. Strategies to determine the effect and extent of polymer coordination to the Zn2+ ion are discussed. The study of polymer-based NCPU is extended to a pair of macromolecules, each containing a single ruthenium tris(bipyridine) (Ru(bpy)3) core and multiple pendant arms, which in turn, each contain eight 9,10-diphenylanthracene (DPA) moieties. A power-dependence study of NCPU in this system is reported, and TTA-UC in the weak annihilation kinetic limit was observed. Upconverted fluorescence quantum yields vary linearly with excitation power in both polymers, consistent with the observed kinetic limit. Stern-Volmer experiments have compared the quenching of Ru(bpy)3 phosphorescence (Ph) by monomeric and polymeric DPA. These data show an enhancement in quenching rate constant for the DPA polymer (pDPA). Kinetic analysis of the Ru-DPA polymers has revealed that the energy scheme realized in this system is intrachain TTET from Ru(bpy)3 core to DPA emitter followed by interchain TTA between excited DPA moieties. Low intensity upconverted fluorescence is observed in Ru-DPA containing thin films. Based on the results presented, the requirements of future photophysically-active polymers are discussed with regards to meaningful application in photovoltaics

Sound absorption and reflection from a resonant metasurface : homogenization model with experimental validation

Efficient manipulation of sound waves by some resonant acoustic metasurface designs has recently been reported in the literature. This paper presents a general theoretical framework for the description of sound wave interaction with the resonant metasurface that is independent of the nature of resonators and the excitation. The equations governing the behaviour of the metasurface are upscaled from the rigorous description of its unit cell using the two scale asymptotic homogenisation. The procedure relies on the existence of the boundary layer confined in the vicinity of the resonators operating in the deep subwavelength regime. The model is capable of describing sound interaction with the array of resonators positioned above or upon the substrate, so that the out of plane direction becomes an additional degree of freedom in the design. It is shown that at the leading order, the behaviour of the resonant surface is described in terms of the effective admittance, whose unconventional properties makes it possible to achieve the total sound absorption at multiple frequencies, broadband absorption, the phase reversal of the reflected wave at resonance and the control of the enclosure modes. The theory is validated by experiments performed in the impedance tube and in the anechoic environment using a surface array of spherical Helmholtz resonators with the extended inner neck. Experimental results confirm the effectiveness and robustness of the resonant surface for control of sound waves

Contrôle des installations d’assainissement non collectif : l’apport déterminant des outils de diagnostic non destructifs

Depuis juillet 2012, un nouveau cadre juridique s’applique aux installations d’assainissement non collectif, visant à améliorer leur contrôle et leur rénovation progressive. Cette note nous présente une méthodologie de contrôle simplifié des installations élaborée grâce l’apport déterminant des outils de diagnostic non destructifs

Dynamic behaviour of an asymmetric building: Experimental and numerical studies

AbstractThe paper presents a study on the seismic assessment of a 21-story building having an asymmetrical plan. The study applies the approach using in-situ measurements to assess the building's seismic performance. According to preliminary observations on site, the soil may have a significant influence on the building's behaviour. That is why it is important to isolate the behaviour of the building from the soil effect (fixed-base structure). First, in-situ dynamic measurements are conducted to identify dynamic characteristics of the building. The Frequency Domain Decomposition (FDD) method is used to determine the vibration modes of the building in three dimensions (3D). First three vibration modes with close frequencies and unusual mode shapes were identified, which shows the relevance of the used method in the case of buildings having complex behaviour. Second, the relevance of the applied approach was checked by using 3D Finite Element (FE) modelling, in both cases: fixed-base structure and soil + structure system

Beyond 2020: How General Education Archaeology Curricula Should Adapt to the COVID-19 Pandemic

Archaeology often justifies its existence by invoking the trope that we must learn about the past in order to create a better future. The COVID-19 pandemic is itself an event that will enter the historical record. Thus, the universality of this public health crisis is a unique opportunity to assess the relevance of university-level archaeology curricula to our present historical moment. We studied an upper division general education course on the archaeology of complex societies at a public liberal arts college in California. The instrument of data collection was a questionnaire administered at the end of the Fall 2020, Spring 2021, and Spring 2022 semesters. Students read an article about archaeological approaches to pandemics, then reflected on how it connected to course content and to their own experiences during the COVID-19 pandemic. Content analysis of student responses suggests that course themes of complex societies, the environment, archaeological evidence, the future, and social hierarchy resonated most with students on both intellectual and personal levels. We also identified emergent concerns with diseases (COVID-19 and others) and cultural responses to them, employment status, and psychological effects, suggesting that these themes are increasingly relevant to archaeology students during and beyond the COVID-19 pandemic