2,091 research outputs found

    Neutron capture cross section measurements of 238U, 241Am and 243Am at n_TOF

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    Proposal: Neutron capture cross section measurements of 238U, 241Am and 243Am at n_TOFThe increase of the world energy demand and the need of low carbon energy sources have triggered the renaissance and/or enhancement of nuclear energy in many countries. Fundamental nuclear physics can contribute in a practical way to the sustainability and safety of the nuclear energy production and the management of the nuclear waste. There exists a series of recent studies which address the most relevant isotopes, decay data, nuclear reaction channels and energy ranges which have to be investigated in more detail for improving the design of different advanced nuclear systems [1] and nuclear fuel cycles [2]. In this proposal, we aim at the measurement of the neutron capture cross sections of 238U, 241Am and 243Am. All three isotopes are listed in the NEA High Priority Request List [37], are recommended for measurements [1] and play an important role in the nuclear energy production and fuel cycle scenarios. The measurements will provide as well valuable nuclear structure data necessary for the improvement of nuclear models and the statistical interpretation of the nuclear propertiesPostprint (author's final draft

    Design of new highly functional polymer grafted polyhipes for proteins immobilization

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    PolyHIPE have proven to be useful in a large variety of applications included column filtration/separation, supported organic chemistry, as media for tissue engineering and 3D cell culture.1 The ability to conveniently modify pHIPE surfaces with functional groups is essential to opening new applications areas. The most promising method to conveniently modify pHIPE surface with a high density of functional groups is the “grafting from” approach. Stable polymer brushes covalently attached to the surface posses excellent mechanical and chemical robustness and offer the flexibility to introduce a large variety of functional monomers.2 We developed a new and unique pHIPE platform by incorporation of a polymerizable monomer with amino group into the HIPE available for different post in situ polymerization. The pHIPE with amino groups on the surface (pHIPE-NH2) can be directly used for the ring opening polymerization of amino acids N-carboxyanhydrates (NCAs) monomers to make pHIPE-g-polypeptide (such as pHIPE-g-poly(L-Benzyl Glutamate)) or easily converted to an atom transfer radical polymerization (ATRP) initiator for activators generated electron transfer (AGET) ATRP of tert-Butyl acrylate monomers. The polymers grafted can be deprotected to form pHIPE-g-poly(glutamic acid) or pHIPE-g-poly(acrylic acid) with reactive groups, on the surface of the pHIPE, available for further bioconjugation

    Sanaa National Museum. Collection of Epigraphic and Archaeological Artifacts from al-Jawf Sites. Part II.

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    L'ouvrage est en anglais/arabe.C'est le deuxième volume consacré aux collections épigraphiques et archéologiques provenant des sites du Jawf, déposées au musée National de Sanaa, Yémen. Ce volume contient 130 pièces composées des inscriptions, des stèles inscrites, plaques en pierre incisées, fragments des piliers, objets en bronze et des bijoux. La plupart de ces pièces datent des VIIIe-Ier s. av. J.-C

    Interoperability and computational framework for simulating open channel hydraulics: application to sensitivity analysis and calibration of Gironde Estuary model

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    Water resource management is of crucial societal and economic importance, requiring a strong capacity for anticipating environmental change. Progress in physical process knowledge, numerical methods and computational power, allows us to address hydro-environmental problems of growing complexity. Modeling of river and marine flows is no exception. With the increase in IT resources, environmental modeling is evolving to meet the challenges of complex real-world problems. This paper presents a new distributed Application Programming Interface (API) of the open source TELEMAC-MASCARET system to run hydro-environmental simulations with the help of the interoperability concept. Use of the API encourages and facilitates the combination of worldwide reference environmental libraries with the hydro-informatic system. Consequently, the objective of the paper is to promote the interoperability concept for studies dealing with such issues as uncertainty propagation, global sensitivity analysis, optimization, multi-physics or multi-dimensional coupling. To illustrate the capability of the API, an operational problem for improving the navigation capacity of the Gironde Estuary is presented. The API potential is demonstrated in a re-calibration context. The API is used for a multivariate sensitivity analysis to quickly reveal the most influential parameters which can then be optimally calibrated with the help of a data assimilation technique

    Droplet entrainment from a single wave propagating in a stratified air-water pipe flow

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    We investigate the distribution of sizes and velocities of droplets detached from a single roll wave propagating in a pipe. The wave is induced by a pulse in liquid flowrate in a stratified air-water flow. Due to the shear applied on the crest of the wave by the faster gas stream, droplets are formed and entrained by the gas. Detection and tracking of the droplets is performed by image processing. The distributions of sizes and velocities of the droplets are determined in the center of the pipe for various distances to the roll wave and compared to those measured for higher gas flowrate when droplets are produced from all the roll waves formed naturally at the gas-liquid interface without external forcing

    Stability of trailing vortices with radial stratification

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    We look at the effects of the radial density stratification on the stability of the q-vortex, a commonly accepted model for aircraft trailing vortices. It has been demonstrated that the 2D Lamb-Oseen vortex develops a Rayleigh-Taylor instability when its core is heavier than the surrounding uid (Joly,Fontane & Chassaing 2005, Sipp et al. 2005). The underlying mechanism relies on baroclinic vorticity generation due to any misalignment between the density gradient and the centripetal acceleration field. The instability is triggered provided that the density decreases radially somewhere in the vortex core. This mechanism is also active in the 3D trailing vortex and affects its stability characteristics due to the addition of an axial component in the acceleration field. We show that the unstable center modes of the homogeneous case (Fabre & Jacquin 2004) are promoted in a q-vortex with a heavy core. Their growth rate increases while their m-spiral structure is preserved. For an Atwood number At = 0:5, their predicted growth rate can be ten times the ones found in the homogeneous case. Furthermore, the unstable domain is extended far beyond the neutral curve in the homogeneous case, with unstable modes observed for Swirl numbers up to q = 5. It is argued here that corresponding density perturbations could eventually lead to the development of new and original strategies to decrease the lifespan of aircraft trailing vortices and greatly reduce their unwanted side-effects on contrails persistence and air traffic regulations
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