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Mapping of groundwater potential zones in the drought-prone areas of south Madagascar using geospatial techniques

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Geoscience Frontiers 2020年第4期11卷 1403-1413页

作者： Charles Serele Ana Perez-Hoyos francois Kayitakire UNICeF Madagascar european Commission Joint Research Centre(JRC)Via E.Fermi 2749I-21027IspraVAItaly

The southern regions of Madagascar have the country’s lowest water supply coverage and are highly vulnerable to *** to potable drinking water is a major challenge for the local *** droughts lead to annual emergency appeals to save the lives of acute malnourished ***’s response consisting in providing potable drinking water through the drilling of boreholes has been challenged by the complex hydrogeology,the low yield of boreholes and high-level salinity of water,the lack of reliable groundwater data and the weak capacity of the drilling *** constraints result in a high rate of drilling *** improve drilling success and provide more potable drinking water to local communities,it is vital to undertake reliable groundwater *** Madagascar and the european Union delegation in Madagascar collaborated on the use of satellite imagery to improve sector knowledge and access to safe and clean water for local communities in southern *** methodology relies on produce thematic layers of groundwater potential ***,these thematic layers were overlaid with ground-based hydrogeological data to map the groundwater potential zones(GWP) and identify the most suitable sites for borehole siting and *** of this study are very encouraging,and the integrated approach used has proven its applicability in mapping groundwater potential areas in the eight drought-affected areas of south *** groundwater potential zone map is being used by UNICeF and partners to plan water supply projects and identify the best sites for positioning new boreholes and reduce the likelihood of drilling ***,the project developed a database of groundwater resources,which will improve knowledge of the regional hydrogeological context and strengthen the capacity of the water *** learnt from this study show that an integration of the groundwater potential zone map with demographics a

关键词： Groundwater potential zones(GWP) Overlay analysis Remote sensing Geographic information system(GIS) South Madagascar

Inverse Scattering for a Schr■dinger Operator with a Repulsive Potential

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Acta Mathematica Sinica,english Series 2006年第5期22卷 1485-1492页

作者： francois NICOLeAU Laboratoire de Mathéatiques Jean Leray UMR CNRS-UN 6629 Département de Mathématiques2 rue de la Houssinière BP 92208 F-44322 Nantes cedex 03 France

We consider a pair of Hamiltonians （H, H0） on L2（R^n）, where H0=p^2 -x^2 is a SchrSdinger operator with a repulsive potential, and H = H0＋V（x）. We show that, under suitable assumptions on the decay of the elect... 详细信息

关键词： Inverse scattering Repulsive potential

Visualization of bHLH transcription factor interactions in living mammalian cell nuclei and developing chicken neural tube by FReT

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Cell Research 2006年第6期16卷 585-598页

作者： francois Guillemot UK London NW7 1AA Mill Hill Division of Molecular Neurobiology National Institute for Medical Research The Ridgeway

Members of the basic helix-loop-helix(bHLH)gene family play important roles in vertebrate *** thisstudy,confocal microscopy-based fluorescence resonance energy transfer(FReT)is used to monitor bHLH protein-proteininteractions under various physiological ***-specific bHLH activators,NeuroD1,Mashl,Neurogeninl(Ngn1),Neurogenin2(Ngn2),and ubiquitous expressed e47 protein are tagged with enhanced yellow fluorescenceprotein(eYFP)and enhanced cyan fluorescence protein(eCFP),*** subcellular localization and mobilityof bHLH fusion proteins are examined in HeK293 *** transient transfection and in ovo electroporation,four pairsof tissue-specific bHLH activators and e47 protein are over-expressed in HeK293 cells and developing chick embryoneural *** the acceptor photobleaching method,FReT could be detected between these bHLH protein pairs inthe nuclei of transfected cells and developing neural ***/e47 and Ngn2/e47 FReT pairs show higher FReTefficiencies in the medial and the lateral half of chick embryo neural tube,*** suggests that these bHLHprotein pairs formed functional DNA-protein complexes with regulatory elements of their downstream target genes inthe specific *** work will help one understand the behaviours of bHLH factors in vivo.

关键词： bHLH confocal microscopy chick embryo neural tube FReT in ovo electroporation photobleach

Conditions for Set Agreement with an Application to Synchronous Systems

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Journal of Computer Science & Technology 2009年第3期24卷 418-433页

作者： francois Bonnet Michel Raynal IRISA University of Rennes35042 Rennes CedexFrance

The k-set agreement problem is a generalization of the consensus problem： considering a system made up of n processes where each process proposes a value, each non-faulty process has to decide a value such that a decided value is a proposed value, and no more than k different values are decided. While this problem cannot be solved in an asynchronous system prone to t process crashes when t≥ k, it can always be solved in a synchronous system; [t/k]＋1 is then a lower bound on the number of rounds （consecutive communication steps） for the non-faulty processes to decide. The condition-based approach has been introduced in the consensus context. Its aim was to both circumvent the consensus impossibility in asynchronous systems, and allow for more efficient consensus algorithms in synchronous systems. This paper addresses the condition-based approach in the context of the k-set agreement problem. It has two main contributions. The first is the definition of a framework that allows defining conditions suited to the l-set agreement problem and the second is a generic synchronous k-set agreement algorithm based on conditions.

关键词： agreement problem condition efficiency lower bound synchronous system

Discrete Duality Finite Volume Discretization of the Thermal-P_(N) Radiative Transfer equations on General Meshes

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Communications in Computational Physics 2022年第2期31卷 398-448页

作者： francois Hermeline Universite Paris-Saclay Laboratoire en Informatique Haute Performance pour le Calcul et la simulationCEADAMDIF91297 ArpajonFrance

The discrete duality finite volume method has proven to be a practical tool for discretizing partial differential equations coming from a wide variety of areas of physics on nearly arbitrary *** main ingredients of the method are:(1)use of three meshes,(2)use of the Gauss-Green theorem for the approximation of derivatives,(3)discrete integration by *** this article we propose to extend this method to the coupled grey thermal-P_(N) radiative transfer equations in Cartesian and cylindrical coordinates in order to be able to deal with two-dimensional Lagrangian approximations of the interaction of matter with *** stability under a Courant-Friedrichs-Lewy condition and the preservation of the diffusion asymptotic limit are proved while the experimental second-order accuracy is observed with manufactured *** numerical experiments are reported which show the good behavior of the method.

关键词： Hybrid multiscale models radiative transfer equation grey P_(N)approximation discrete duality finite volume method

Maximizing the Delivery of MPR Broadcasting Under Realistic Physical Layer Assumptions

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Journal of Computer Science & Technology 2008年第3期23卷 451-460页

作者： francois Ingelrest David Simplot-Ryl LCAV EPFLCH-1015LausanneSwitzerland IRCICA/LIFL CNRS UMR 8022Univ.Lille 1INRIA Lille-Nord EuropeFrance

It is now commonly accepted that the unit disk graph used to model the physical layer in wireless networks does not reflect real radio transmissions, and that a more realistic model should be considered for experimental simulations. Previous work on realistic scenarios has been focused on unicast, however broadcast requirements are fundamentally different and cannot be derived from the unicast case. Therefore, the broadcast protocols must be adapted in order to still be efficient under realistic assumptions. In this paper, we study the well-known multipoint relay broadcast protocol （MPR）, in which each node has to choose a set of 1-hop neighbors to act as relays in order to cover the whole 2-hop neighborhood. We give experimental results showing that the original strategy used to select these multipoint relays does not suit a realistic model. On the basis of these results, we propose new selection strategies solely based on link quality. One of the key aspects of our solutions is that our strategies do not require any additional hardware and may be implemented at the application layer, which is particularly relevant to the context of ad hoc and sensor networks where energy savings are mandatory. We finally provide new experimental results that demonstrate the superiority of our strategies under realistic physical assumptions.

关键词： ad hoc network multipoint relay broadcasting realistic physical layer sensor network

The Micromechanics of Biological and Biomimetic Staggered Composites

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Journal of Bionic engineering 2012年第4期9卷 446-456页

作者： Sacheen Bekah Reza Rabiei francois Barthelat Department of Mechanical engineering McGill University 817 Sherbrooke Street West Montreal QC H3A 2K6 Canada

Natural materials such as bone, tooth and nacre achieve attractive properties through the ＂staggered structure＂, which consists of stiff, parallel inclusions of large aspect ratio bonded together by a more ductile and tougher matrix. This seemingly simple structure displays sophisticated micromechanics which lead to unique combinations of stiffness, strength and toughness. In this article we modeled the staggered structure using finite elements and small Representative Volume elements （RVes） in order to explore microstructure-property relationships. Larger aspect ratio of inclusions results in greater stiffiless and strength, and also significant amounts of energy dissipation provided the inclusions do not fracture in a brittle fashion. Interestingly the ends of the inclusions （the junctions） behave as crack-like features, generating theoretically infinite stresses in the adjacent inclusions. A fracture mechanics criterion was therefore used to predict the failure of the inclusions, which led to new insights into how the interfaces act as a ＂＇soft wrap＂ for the inclusions, completely shielding them from excessive stresses. The effect of statistics on the mechanics of the staggered structure was also assessed using larger scale RVes. Variations in the microstructure did not change the modulus of the material, but slightly decreased the strength and significantly decreased the failure strain. This is explained by strain localization, which can in turn be delayed by incorporating waviness to the inclusions. In addition, we show that the columnar and random arrangements, displaying different deformation mechanisms, lead to similar overall prop- erties. The guidelines presented in this study can be used to optimize the design of staggered synthetic composites to achieve mechanical performances comparable to natural materials.

关键词： biological materials biomimetics representative volume element fracture mechanics finite element analysis

Multiscale Mechanics and Optimization of Gastropod Shells

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Journal of Bionic engineering 2011年第4期8卷 357-368页

作者： Mostafa Yourdkhani Damiano Pasini francois Barthelat Department of Mechanical engineering McGill University 817 Sherbrooke Street West Montreal QC H3A 2K6 Canada

A vast majority of mollusks grow a hard shell for protection. The structure of these shells comprises several levels of hierarchy that increase their strength and their resistance to natural threats. This article focuses on nacreous shells, which are composed of two distinct layers. The outer layer is made of calcite, which is a hard but brittle material, and the inner layer is made of nacre, a tough and ductile material. The inner and outer layers are therefore made of materials with distinct structures and properties. In this article, we demonstrate that this system is optimum to defeat attacks from predators. A two-scale mod- eling and optimization approach was used. At the macroscale, a two-layer finite element model of a seashell was developed to capture shell geometry. At the microscale, a representative volume element of the microstructure of nacre was used to model the elastic modulus of nacre as well as a multiaxial failure criterion, both expressed as function of microstructural parameters. experiments were also performed on actual shells of red abalone to validate the results obtained from simulations and gain insight into the way the shell fails under sharp perforation. Both optimization and experimental results revealed that the shell displays optimum performance when two modes of failure coincide within the structure. Finally, guidelines for designing two-layer shells were proposed to improve the performance of engineered protective systems undergoing similar structural and loading conditions.

关键词： seashell multiscale modeling representative volume element failure criterion nacre multiscale optimization

Quantitative morphometric analysis of the Jama River profile in a tectonically active margin (Northwestern ecuador)

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Journal of Mountain Science 2018年第5期15卷 966-975页

作者： Pedro S.B. ReYeS Mauricio e. VALAReZO Jenry CORDOVA francois A. MICHAUD Camilo ZAPATA Department of Geology Escuela Politécnica Nacional Ladrón de Gueuara E11-253 PO.Box 17-01-2759 Quito Ecuador C-eostrat S.A. Jorge Drom N39-188y Gaspar de Villaroel Quito Ecuador Department of Civil and environmental engineering Escuela Politécnica National Ladrón de Guevara E11-253 PO.Box17-ol-2759 Quito Ecuador Sorbonne Université Université Cote d'Azur IRD CNRS Observatoire de la Cdte d'Azur C-eoazur 250 rue A. EinsteinSophia Antipolis 06560 Valbonne France

The longitudinal profile of a river channel can be described in function of mathematical expressions. The logarithmic fit is the most used method to describe the relative equilibrium of a channel elevation profile. Rivers showing zones of high channel gradient and convex-upward profiles can be evaluated in function of the offset distance with respect to the logarithmic curve. The Jama River profile has been constructed using differential GPS data for the downstream reach and 4-m-grid DeM data base for the remaining headward profile. The resulting longitudinal profile shows a prominent knickpoint of about 80 m in elevation characterized by sharp local convexity. The offset distance in vertical direction from the logarithmic plot is interpreted as the successive accumulation of multiple uplift episodes associated with the Jama Fault System activity. The horizontal offset is suggested to represent the remaining retreated distance for the upstream propagation of the Jama knickpoint. The highly resistant Cretaceous rocks outcropping along the Jama knickpoint reach acts as an inflection point between two subprofiles that show well-fitted logarithmic curves, thereby representing a temporary partitioned equilibrium along the Jama River profile.

关键词： Morphometry Jama River Stream profile Active tectonics