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541.
Alain Tamayo Joaquín Huerta Carlos Granell Laura Díaz Ricardo Quirós 《Transactions in GIS》2009,13(S1):47-61
A key problem with sensor networks is achieving interoperability between different networks potentially built using different software and hardware platforms. Services interfaced by the Open Geospatial Consortium (OGC) specifications allow GIS clients to access geospatial data without knowing the details about how these data are gathered or stored. Currently, OGC is working on a set of interoperable interfaces and metadata encodings known as Sensor Web Enablement (SWE) that enables the integration of heterogeneous sensor systems and measurements into geospatial information infrastructures. In this article we present the implementation of gvSOS, a new module for gvSIG to connect to Sensor Observation Services (SOS). The gvSOS client module allows gvSIG users to interact with SOS servers, displaying the information gathered by sensors as a layer composed by features. We present the software engineering development process followed to build the module. For each step of the process we specify the main obstacles found during the development such as restrictions of the gvSIG architecture, inaccuracies in the OGC specifications, and a set of common problems found in current SOS server implementations available on the Internet. For most of the problems found we propose a solution, or at least we present a path that might lead to it. 相似文献
542.
The local structures of divalent Zn, Cu, and Pb sorbed on the phyllomanganate birnessite (Bi) have been studied by powder and polarized extended X-ray absorption fine structure (EXAFS) spectroscopy. Metal-sorbed birnessites (MeBi) were prepared at different surface coverages by equilibrating at pH 4 a Na-exchanged buserite (NaBu) suspension with the desired aqueous metal. Me/Mn atomic ratios were varied from 0.2% to 12.8% in ZnBi and 0.1 to 5.8% in PbBi. The ratio was equal to 15.6% in CuBi. All cations sorbed in interlayers on well-defined crystallographic sites, without evidence for sorption on layer edges or surface precipitation. Zn sorbed on the face of vacant layer octahedral sites (□), and shared three layer oxygens (Olayer) with three-layer Mn atoms (Mnlayer), thereby forming a tridentate corner-sharing (TC) interlayer complex (Zn-3Olayer-□-3Mnlayer). TCZn complexes replace interlayer Mn2+ (Mninter2+) and protons. TCZn and TCMninter3+ together balance the layer charge deficit originating from Mnlayer4+ vacancies, which amounts to 0.67 charge per total Mn according to the structural formula of hexagonal birnessite (HBi) at pH 4. At low surface coverage, zinc is tetrahedrally coordinated to three Olayer and one water molecule ([IV]TC complex: (H2O)-[IV]Zn-3Olayer). At high loading, zinc is predominantly octahedrally coordinated to three Olayer and to three interlayer water molecules ([VI]TC complex: 3(H2O)-[VI]Zn-3Olayer), as in chalcophanite ([VI]ZnMn34+O7·3H2O). Sorbed Zn induces the translation of octahedral layers from −a/3 to +a/3, and this new stacking mode allows strong H bonds to form between the [IV]Zn complex on one side of the interlayer and oxygen atoms of the next Mn layer (Onext): Onext…(H2O)-[IV]Zn-3Olayer. Empirical bond valence calculations show that Olayer and Onext are strongly undersaturated, and that [IV]Zn provides better local charge compensation than [VI]Zn. The strong undersaturation of Olayer and Onext results not only from Mnlayer4+ vacancies, but also from Mn3+ for Mn4+ layer substitutions amounting to 0.11 charge per total Mn in HBi. As a consequence, [IV]Zn,Mnlayer3+, and Mnnext3+ form three-dimensional (3D) domains, which coexist with chalcophanite-like particles detected by electron diffraction. Cu2+ forms a Jahn-Teller distorted [VI]TC interlayer complex formed of two oxygen atoms and two water molecules in the equatorial plane, and one oxygen and one water molecule in the axial direction. Sorbed Pb2+ is not oxidized to Pb4+ and forms predominantly [VI]TC interlayer complexes. EXAFS spectroscopy is also consistent with the formation of tridentate edge-sharing ([VI]TE) interlayer complexes (Pb-3Olayer-3Mn), as in quenselite (Pb2+Mn3+O2OH). Although metal cations mainly sorb to vacant sites in birnessite, similar to Zn in chalcophanite, EXAFS spectra of MeBi systematically have a noticeably reduced amplitude. This higher short-range structural disorder of interlayer Me species primarily originates from the presence of Mnlayer3+, which is responsible for the formation of less abundant interlayer complexes, such as [IV]Zn TC in ZnBi and [VI]Pb TE in PbBi. 相似文献
543.
We have developed a new photochemical model of Titan's atmosphere which includes all the important compounds and reactions in spherical geometry from the surface to 1240 km. Compared to the previous model of Yung et al. (1984, Astrophys. J. Suppl. 55, 465-506), the most significant recent change in the reactions used is the updated methane photodissociation scheme (Mordaunt et al. 1993, J. Chem. Phys. 98(3), 2054-2065). Moreover, the transfer of the solar radiation in the atmosphere and the photolysis rates have been calculated by using a Monte Carlo code. Finally, the eddy diffusion coefficient profile is adjusted in order to fit the mean vertical distribution of HCN retrieved from millimeter groundbased observations of Tanguy et al. (1990, Icarus, 85, 43-57) using new values for the boundary flux of atomic nitrogen (Strobel et al. 1992, Icarus 100, 512-526). We have run the model in both steady-state and diurnal modes, with 62 speices involved in 249 reactions. There is little difference between diurnal and steady-state results. Overall our results are in a closer agreement with the abundances inferred from the Voyager infrared measurements at the equator than the Yung et al. results. We find that the catalytic scheme for H recombination invoked by Yung et al. only slightly improves the model results and we conclude that this scheme is not essential to fit observations. 相似文献
544.
545.
Bruno Goutorbe Francis Lucazeau Alain Bonneville 《Geophysical Journal International》2007,170(2):913-922
Bottom-hole temperatures (BHT) from oil exploration provide useful constraints on the subsurface thermal regime, but they need to be corrected to obtain the equilibrium temperature. In this work, we introduce several BHT correction methods and compare them using a large Australian data set of more than 650 groups of multiple BHT measurements in about 300 oil exploration boreholes. Existing and suggested corrections are classified within a coherent framework, in which methods are divided into: line/cylinder source; instantaneous/continuous heat extraction; one/two component(s). Comparisons with reservoir test temperatures show that most of the corrections lead to reliable estimates of the formation equilibrium temperature within ±10 °C, but too few data exist to perform an intercomparison of the models based on this criterion. As expected, the Horner method diverges from its parent models for small elapsed times (or equivalently large radii). The mathematical expression of line source models suffers from an unphysical delay time that also restrains their domain of applicability. The model that takes into account the difference of thermal properties between circulating mud and surrounding rocks—that is the two-component model—is delicate to use because of its high complexity. For these reasons, our preferred correction methods are the cylindrical source models. We show that mud circulation time below 10 hr has a negligible effect. The cylindrical source models rely on one parameter depending on the thermal diffusivity and the borehole radius, which are poorly constrained, but the induced uncertainty on the extrapolations remains reasonably low. 相似文献
546.
Magdala Tesauro Christine Hollenstein Ramon Egli Alain Geiger Hans-Gert Kahle 《Journal of Geodynamics》2006,42(4-5):194-209
The kinematic field of central western Europe is characterized by relatively small movements (around 1–2 mm/year) and diffuse seismicity with earthquakes occurring mostly in the shallow crust (within 15 km), prevalently concentrated along the Alps and the European Cenozoic Rift System (ECRIS). In order to study and constrain the current crustal kinematic field we reconstructed the velocity and the strain field using permanent GPS stations, belonging to different networks (AGNES, EUREF, REGAL, RGP). The 2D strain rate tensor has been calculated using the method of least-squares collocation. Our results show that the area of maximum compression is located along the Alpine chain, where maximum values of 7 ± 2 nstrain/year are found, while maximum extension is measured between the Armorican Massif and the Massif Central, where values of 4 ± 2 nstrain/year are reached.The earthquakes with M > 3.0, have been used to estimate the seismic strain rates, while the style of the seismic deformation was reconstructed from the fault plane solutions (FPS) available from the literature. Relatively high values of seismic strain rates (around 10 nstrain/year) are measured along the Alpine Chain and the ECRIS. Results obtained by geodetic and seismic data are quite in agreement and reflect the different tectonic evolution of the geological features characterizing the area of study. The orientation of the compressional geodetic and seismic strain axes are NW-SE in most of the area of study, on account of the action of plate boundary forces. A rotation of the same axes to N-S direction along the eastern Alps, possibly related to the Adria convergence, is found. 相似文献
547.
The coupling of optimal economic growth and climate dynamics 总被引:1,自引:0,他引:1
Olivier Bahn Laurent Drouet Neil R. Edwards Alain Haurie Reto Knutti Socrates Kypreos Thomas F. Stocker Jean-Philippe Vial 《Climatic change》2006,79(1-2):103-119
In this paper, we study optimal economic growth programs coupled with climate change dynamics. The study is based on models derived from MERGE, a well established integrated assessment model (IAM). We discuss first the introduction in MERGE of a set of “tolerable window” constraints which limit both the temperature change and the rate of temperature change. These constraints, obtained from ensemble simulations performed with the Bern 2.5-D climate model, allow us to identity a domain intended to preserve the Atlantic thermohaline circulation. Next, we report on experiments where a two-way coupling is realized between the economic module of MERGE and an intermediate complexity “3-D-” climate model (C-GOLDSTEIN) which computes the changes in climate and mean temperature. The coupling is achieved through the implementation of an advanced “oracle based optimization technique” which permits the integration of information coming from the climate model during the search for the optimal economic growth path. Both cost-effectiveness and cost-benefit analysis modes are explored with this combined “meta-model” which we refer to as GOLDMERGE. Some perspectives on future implementations of these approaches in the context of “collaborative” or “community” integrated assessment modules are derived from the comparison of the different approaches. 相似文献
548.
Characterization and correlation of Upper Jurassic (Oxfordian) bentonite deposits in the Paris Basin and the Subalpine Basin, France 总被引:1,自引:0,他引:1
Pierre Pellenard Jean-Francois Deconinck Warren D. Huff† Jacques Thierry‡ Didier Marchand‡ Dominique Fortwengler§ Alain Trouiller¶ 《Sedimentology》2003,50(6):1035-1060
Abstract Explosive volcanic activity is recorded in the Upper Jurassic of the Paris Basin and the Subalpine Basin of France by the identification of five bentonite horizons. These layers occur in Lower Oxfordian (cordatum ammonite zone) to Middle Oxfordian (plicatilis zone) clays and silty clays deposited in outer platform environments. In the Paris Basin, a thick bentonite (10–15 cm), identified in boreholes and in outcrop, is dominated by dioctahedral smectite (95%) with trace amounts of kaolinite, illite and chlorite. In contrast, five bentonites identified in the Subalpine Basin, where burial diagenesis and fluid circulation were more important, are composed of a mixture of kaolinite and regular or random illite/smectite mixed-layer clays in variable proportions, indicating a K-bentonite. In the Subalpine Basin, a 2–15 cm thick bentonite underlain by a layer affected by sulphate–carbonate mineralization can be correlated over 2000 km2. Euhedral zircon, apatite and biotite crystals have been identified in all the bentonites. The geochemical composition of the bentonites in both basins is characterized by high concentrations of Hf, Nb, Pb, Ta, Th, Ti, U, Y, Zr and low concentrations of Cr, Cs and Rb. Biostratigraphical and geochemical data suggest that the thick bentonite in the Paris Basin correlates with the thickest bentonite in the Subalpine Basin, located 400 km to the south. These horizons indicate that significant explosive volcanic events occurred during the Middle Oxfordian and provide potential long-distance isochronous marker beds. Immobile element discrimination diagrams and rare-earth element characteristics indicate that the original ash compositions of the thickest bentonites correspond to a trachyandesitic source from a within-plate alkaline series that was probably related to North Atlantic rifting. 相似文献
549.
EDTA and ATMP are synthetic chelatingagents used in many industrial applications. Becauseof their low biodegradability, they are present inmany aquatic systems where their strong complexingcapacities can modify the transfer of toxic heavymetals between solid and liquid phases.The remobilization of Cu, Pb and Cd from pollutedsuperficial river sediments in the presence of twosynthetic organic ligands (a polycarboxylate, EDTA,and a phosphonate, ATMP) is investigated as a functionof reaction time to determine the time necessary toreach dissolutive equilibrium, and as a fonction ofthe complexing agent concentration.The dissolutive equilibrium times are similar (10 to20 hours) and the solubilizing power of ATMP isslightly lower than that of EDTA. The curves ofsolubilization of metals in the presence of thecomplexing agents present a shape of a chelateconcentration desorption edge, for a chelate rangebetween 10-5 to 10-3 mol L-1, thesolubilised metals increasing dramatically. Thisremobilization is the result of a competition betweenassociation with the solid phase and dissolvedcomplexation. With EDTA, the desorption order ofmetals seems to be imposed by association with thesolid. For ATMP is it the chelate complexing strengthwhich determines this order. 相似文献
550.
Alain Dupont Jacqueline Vander Auwera Christian Pin Ştefan Marincea Tudor Berza 《Mineralium Deposita》2002,37(6-7):568-586