Shear modulus and damping ratio of grouted sand

An experimental comparative study of three different grouted sands in terms of their effects on the values of two dynamic properties is presented. The dynamic properties studied are the shear modulus and the damping ratio which are determined with resonant column tests and cyclic triaxial tests. The behaviour of a pure Fontainebleau sand is compared with the behaviour of a Fontainebleau sand grouted with a silicate grout, a micro-fine cement grout and a mineral grout. The effects of the grouting treatment, the type of grout, the confining pressure, and the strains, on the shear modulus and the damping ratio are studied. The test results have shown that grouting improves the stiffness of the sand especially for small strains. Whatever the type of material, confining stress improves the shear modulus whereas it has a negligible effect on the damping ratio. When strain increases, the shear modulus decreases and the damping ratio increases.     

Statistical Evaluation of Compositional Differences Between Upper Eocene Impact Ejecta Layers

Melt droplets formed by the impact of a large meteorite impact event(s) have been found in upper Eocene marine sediments from the Atlantic, Pacific, and Indian oceans. The number of discreet impacts that occurred to form these melt droplets can be gleaned by compositionally analysing the droplets and establishing the number of distinct groups. Previous studies have inferred two, three, or more source impact events, although we believe the statistical techniques used to distinguish the groupings are open to criticism. Multivariate and univariate analysis (including discriminant analysis) of the major-element composition of an increased data set of impact melt ejecta droplets have been performed. The results demonstrate that the uppermost ejecta layer is geochemically distinct from other late Eocene melt ejecta. Our statistical analysis suggests two underlying, purportedly stratigraphically separate ejecta layers, possess minimal differences that cannot be distinguished clearly from one another by discriminant analysis, which adds to the plausibility that they have a common source. Finally, our results reveal apparent disparities between the new major-element data from this study and data compiled from existing sources.     

Structure-from-motion,multi-view stereo photogrammetry applied to line-scan sediment core images

Journal of Paleolimnology - Images of sediment cores are often acquired to preserve primary color information, before such profiles are altered by subsequent sampling and destructive analyses. In...     

Quota discarding and distributive justice: The case of the under-10 m fishing fleet in Sussex,England

Marine fish discarding has become a contentious environmental issue, but little attention has been paid to the moral grievances that sometimes underlie discarding practices. This article explores such a moral grievance through a case study of the under-10 m fishery in Sussex, England, where discarding of cod (Gadus morhua) has become a highly charged issue, skippers blaming it on unjust quota allocations. The moral claim to a greater quota allocation is analysed using two conceptions of distributive justice, entitlement and desert. The conclusion reached is that the under-10 m fleet’s entitlement arguments for a higher quota are weaker than their desert arguments, but that entitlement arguments weigh more heavily than desert arguments with government when it allocates quota.     

Characterization of regional and local scattering effects from small-aperture seismic array recordings

In 1998, four small-aperture arrays separated by 20 km have been deployed in the southern French Alps in order to record the natural seismicity during two consecutive months. One of the main objectives of this experiment was to characterize the heterogeneities that influence the wavefield propagation, by analysis of the coda characteristics recorded by each of the seismic arrays.The time-azimuth-velocity characteristics of the coda phases have been obtained using a high-resolution wavenumber decomposition method.A statistical analysis, using the coda characteristics of the whole data set (20 regional earthquakes) recorded by the four arrays has been performed and lead to the calculation of the density of scattered energy within the medium. Three regional heterogeneous areas (> 10 km) have been characterized, and are located in the N–NE, W and S directions from the four arrays. Scattered energy is also located at local distances (< 10 km) from the four arrays.The comparison of the waveforms recorded (i) with one of the array, for different groups of earthquakes, and (ii) with the four arrays, for one group of earthquakes, show that the geometrical configuration of the source–scattering area–recording site system can strongly influence the energetic distributions related to the secondary phases of the seismograms.In particular cases, we experimentally show that the interactions of the direct wavefield with the heterogeneous structures of the medium can be sufficiently energetic to induce secondary scattered phases that dominate the seismic motions recorded at a given site. In such case, these effects should be taken into account for the quantification of the expected ground motion recorded during an earthquake.     

Spectroscopy of Yamato 984028

Comprehensive spectroscopic characterization of interior and exterior chips of the lherzolitic shergottite Y-984028 has been performed using results from six techniques. Data from UV–visible–near-IR reflectance spectra, thermal (mid-IR) emission spectra, attenuated total reflectance (ATR) spectra, transmission FTIR spectra, Raman microprobe spectra, and Mössbauer spectra of whole rock and mineral separates from this meteorite are integrated and compared. Five of these analytical techniques accurately determined the ～Fo₆₅ composition of the olivine within ±10 mol%. Both transmission FTIR and ATR spectra show broad features near 3500 cm^?1 indicating the presence of OH/H₂O that does not arise from surface water adsorption. The brown color of the Y-984028 olivine is likely due to the presence of nanophase metallic iron particles (npFe⁰) dispersed throughout the olivine during a major shock event on Mars. Y-984028 olivine also contains a significant amount of Fe³⁺, but this cannot be distinguished from Fe³⁺ that is present in pyroxene and possibly clay minerals. This meteorite and the nakhlite MIL03346 are the two most oxidized of the SNC meteorites studied to date, with Fe³⁺ contents consistent with high-temperature equilibration near the QFM oxygen buffer.     

Scale-dependent habitat use by a large free-ranging predator,the Mediterranean fin whale

Since the heterogeneity of oceanographic conditions drives abundance, distribution, and availability of prey, it is essential to understand how foraging predators interact with their dynamic environment at various spatial and temporal scales. We examined the spatio-temporal relationships between oceanographic features and abundance of fin whales (Balaenoptera physalus), the largest free-ranging predator in the Western Mediterranean Sea (WM), through two independent approaches. First, spatial modeling was used to estimate whale density, using waiting distance (the distance between detections) for fin whales along ferry routes across the WM, in relation to remotely sensed oceanographic parameters. At a large scale (basin and year), fin whales exhibited fidelity to the northern WM with a summer-aggregated and winter-dispersed pattern. At mesoscale (20–100 km), whales were found in colder, saltier (from an on-board system) and dynamic areas defined by steep altimetric and temperature gradients. Second, using an independent fin whale satellite tracking dataset, we showed that tracked whales were effectively preferentially located in favorable habitats, i.e. in areas of high predicted densities as identified by our previous model using oceanographic data contemporaneous to the tracking period. We suggest that the large-scale fidelity corresponds to temporally and spatially predictable habitat of whale favorite prey, the northern krill (Meganyctiphanes norvegica), while mesoscale relationships are likely to identify areas of high prey concentration and availability.     

Fully coupled generalized hybrid-mixed finite element approximation of two-phase two-component flow in porous media. Part I: formulation and properties of the mathematical model

This paper is a prequel to that of Marchand et al. (Comput Geosci 16:691–708, 2012), where an efficient and accurate hybrid-mixed finite element approximation for a system of time-dependent nonlinear conservation equations has been formulated, implemented, and tested, which are general enough to represent most of the existing formulations for two-component liquid–gas flow in porous medium with phase exchange, also allowing for any (dis)appearance of one of the phases. Temperature variation is neglected, but capillary effects are included by extended Darcy’s law, and Fickian diffusion is taken into account. The efficiency and stability of the numerical method of Lake (1989) relies on an equivalent reformulation of the otherwise commonly used model in terms of new principal variables and subsequent static (flash) equations allowing more generally for any (dis)appearance of one of the phases without the need of variable switching or unphysical quantities. In particular, the formulation in terms of complementarity conditions allows for an efficient and stable solution by the semismooth Newton’s method.     

Managing coastal evolution in a more sustainable manner. The Conscience approach

This paper summarises the main findings of the Conscience research project, whose primary objective was to define and validate, through pilot applications, a methodology to support the implementation, for European coasts, of concepts such as coastal resilience, favorable sediment status, strategic sediment reservoirs and coastal sediment cells. The Conscience conceptual framework to managing coastal erosion has proved to be an efficient tool, because it provides a consistent approach where objective (data) and subjective (desired status) information are analyzed and compared from the standpoint of a consensus target (objective). Moreover, this is done using the best available knowledge and observations, considering always their level of uncertainty, to conduct a sustainable management policy for coastal erosion. The methodology has been tested in field cases from The Netherlands, Poland, Romania, Spain, United Kingdom and Ireland, to cover different time and space scales, together with a wide range of processes and different management objectives.