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311.
Silveira Mariana V. Casagrande Michéle D. T. 《Geotechnical and Geological Engineering》2021,39(5):3875-3887
Geotechnical and Geological Engineering - This paper presents the results of an experimental program about the behavior and durability of soils reinforced with randomly distributed vegetal fibers... 相似文献
312.
le Prof. J. TRICART 《水文科学杂志》2013,58(4):75-84
Abstract The rivers Gard, Herault and Vidourle which go down very rapidly from the Cevennes into the Mediterranean sea, between very steep slopes, are particulary able to transport débris as a consequence of their very big floods. Nevertheless, during the floods of the autumn 1958, which were of a bi- or tricentenial frequency, only the loams, clays and sands were able to reach the sea during the flood. Shingle was transported in great quantities but only upon short distances, of no; more than 2 or 3 km. Even in such torrents, the transport of shingle is very long, and the greater part of the shingle actually present in the river bed was swept out from the foot of the slopes during the last cold period of the Quaternary, under periglacial conditions. The construction of a dam, at the Moulin de Bertrand in the Hérault valley, which does not allow the transit of shingle, did not result in the modifications in the conditions of transport of the pebbles downstream: the pebbles which are presently transported do not come from the upper valley, but are reworked from the accumulations built up in the bed before the construction of the dam. 相似文献
313.
Emmanuel Roux Joecila Santos da Silva Augusto Cesar Vieira Getirana Marie-Paule Bonnet Stéphane Calmant Jean-Michel Martinez 《水文科学杂志》2013,58(1):104-120
Abstract Satellite radar altimetry is complementary to in situ limnimetric surveys as a means of estimating the water height of large rivers, lakes and flood plains. Production of water height time series by satellite radar altimetry technology requires first the selection of radar ground target locations corresponding to water body surfaces under study, i.e. the definition of “virtual limnimetric stations”. We propose to investigate qualitative and quantitative differences between three representative virtual station creation methodologies: (a) a fully manual method, (b) a semi-automatic method based on a land cover characterization that allows the water body surface under study to be located; and (c) an original fully automatic procedure that exploits a digital elevation model and an estimation of the river width. The results yielded by these three methods are comparable: maximum absolute magnitudes of water height differences being 0.46, 0.26 and 0.15 m for, respectively, 95, 90 and 80% of the water height values obtained. Moreover, more than 67% and 92% of time series jointly produced by the methods present root mean square differences lower than 20 and 50 cm, respectively. The results show that the fully automatic method developed herein provides as reliable results as the fully manual one. This opens the way to use of satellite radar altimetry for the generation of water height time series on a large scale, and considerably extends the applicability of satellite radar altimetry in hydrology. Citation Roux, E., Santos da Silva, J., Vieira Getirana, A. C., Bonnet, M.-P., Calmant, S., Martinez, J.-M. & Seyler, F. (2010) Producing time series of river water height by means of satellite radar altimetry—comparative study. Hydrol. Sci. J. 55(1), 104–120. 相似文献
314.
315.
C. Le Gal La Salle L. Aquilina E. Fourre P. Jean-Baptiste J.-L. Michelot C. Roux D. Bugai T. Labasque C. Simonucci N. Van Meir A. Noret S. Bassot A. Dapoigny D. Baumier P. Verdoux D. Stammose J. Lancelot 《Applied Geochemistry》2012
Following the explosion of reactor 4 at the Chernobyl power plant in northern Ukraine in 1986, contaminated soil and vegetation were buried in shallow trenches dug directly on-site in an Aeolian sand deposit. These trenches are sources of radionuclide (RN) pollution. The objective of the present study is to provide constraints for the Chernobyl flow and RN transport models by characterising groundwater residence time. A radiochronometer 3H/3He method (t1/2 = 12.3 a) and anthropogenic tracers including CFC and SF6 are investigated along with the water mass natural tracers Na, Cl, 18O and 2H. 相似文献
316.
Knut–Andreas Lie Stein Krogstad Ingeborg Skjelkv?le Ligaarden Jostein Roald Natvig Halvor M?ll Nilsen B?rd Skaflestad 《Computational Geosciences》2012,16(2):297-322
Accurate geological modelling of features such as faults, fractures or erosion requires grids that are flexible with respect
to geometry. Such grids generally contain polyhedral cells and complex grid-cell connectivities. The grid representation for
polyhedral grids in turn affects the efficient implementation of numerical methods for subsurface flow simulations. It is
well known that conventional two-point flux-approximation methods are only consistent for K-orthogonal grids and will, therefore, not converge in the general case. In recent years, there has been significant research
into consistent and convergent methods, including mixed, multipoint and mimetic discretisation methods. Likewise, the so-called
multiscale methods based upon hierarchically coarsened grids have received a lot of attention. The paper does not propose
novel mathematical methods but instead presents an open-source Matlab? toolkit that can be used as an efficient test platform for (new) discretisation and solution methods in reservoir simulation.
The aim of the toolkit is to support reproducible research and simplify the development, verification and validation and testing
and comparison of new discretisation and solution methods on general unstructured grids, including in particular corner point
and 2.5D PEBI grids. The toolkit consists of a set of data structures and routines for creating, manipulating and visualising
petrophysical data, fluid models and (unstructured) grids, including support for industry standard input formats, as well
as routines for computing single and multiphase (incompressible) flow. We review key features of the toolkit and discuss a
generic mimetic formulation that includes many known discretisation methods, including both the standard two-point method
as well as consistent and convergent multipoint and mimetic methods. Apart from the core routines and data structures, the
toolkit contains add-on modules that implement more advanced solvers and functionality. Herein, we show examples of multiscale
methods and adjoint methods for use in optimisation of rates and placement of wells. 相似文献
317.
VizualAge, a new computer software tool for analysing U‐Pb data obtained by laser ablation‐inductively coupled plasma‐mass spectrometry, was developed. It consists of a data reduction scheme (DRS) for Iolite (a general mass spectrometry data analysis tool) as well as visualisation routines. In addition to the U/Pb and Th/Pb ages calculated by Iolite’s U‐Pb geochronology DRS, VizualAge also calculates 207Pb/206Pb ages and common Pb corrections for each time‐slice of raw data. Importantly, VizualAge allows one to display a live concordia diagram for visualising data on such a diagram as an integration interval is being adjusted. This provides instantaneous feedback regarding discordance, uncertainty, error correlation and common Pb. Several zircon data sets were used to illustrate how the live concordia could be used as a powerful inspection tool, revealing a single analysis to consist of zones of concordance, metamict areas, as well as inherited cores or younger overgrowths. VizualAge also constructs histograms, conventional and Tera‐Wasserburg type concordia diagrams, as well as 3D U‐Th‐Pb and total U‐Pb concordia diagrams. The precision and accuracy of data reduced with VizualAge are demonstrated with examples of the Ple?ovice, Temora‐2 and Penglai zircon reference materials. Data for zircon from the Long Lake Batholith (Wyoming craton) were used to illustrate how VizualAge calculated common Pb corrections and helped to expose as yet unexplained difficulties with accurately determining 204Pb. 相似文献
318.
Bathymetric and sub-bottom acoustic data were collected in Laguna San Rafael, Chile, to determine sediment yields during the Little Ice Age advance and subsequent retreat of San Rafael Glacier. The sediment volumes and subaqueous landforms imaged are used to interpret the proglacial dynamics and estimate erosion rates from a temperate tidewater glacier over a complete advance-retreat cycle. Sediment yields from San Rafael Glacier averaged 2.7 × 107 m3/a since the end of the Little Ice Age, circa AD 1898, corresponding to average basin-wide erosion rates of 23 ± 9 mm/a; the highest erosion rates, 68 ± 23 mm/a, occurred at the start of the retreat phase, and have since been steadily decreasing. Erosion rates were much lower during glacial advance, averaging at most 7 mm/a, than during retreat. Such large glacial sediment yields over two centuries of advance and retreat suggest that the contribution of sediments stored subglacially cannot account for much of the sediment being delivered to the terminus today. The detailed sub-bottom information of a proglacial lagoon yields important clues as to the timing of erosion, deposition and transfer of glacigenic sediments from orogens to the continental shelves, and the influence of glacier dynamics on this process. 相似文献
319.
Presence of Anthropogenic Markers in Water: A Case Study of the Guaporé River Watershed,Brazil 下载免费PDF全文