Soil structure depends on the association between mineral soil particles (sand, silt, and clay) and organic matter, in which aggregates of different size and stability are formed. Although the chemistry of organic materials, total microbial biomass, and different enzyme activities in different soil particle size fractions have been well studied, little information is available on the structure ...

During a field campaign in the Sahara Desert in southern Morocco, spring 2012, we sampled the vertical grain size distribution of two active dust devils that exhibited different dimensions and intensities. With these in situ samples of grains in the vortices, it was possible to derive detailed vertical grain size distributions and measurements of the lifted relative particle load. Measurements ...

During a field campaign in the Sahara Desert in southern Morocco, spring 2012, we sampled the vertical grain size distribution of two active dust devils that exhibited different dimensions and intensities. With these in situ samples of grains in the vortices, it was possible to derive detailed vertical grain size distributions and measurements of the lifted relative particle load. Measurements ...

aeolian process and subsequently soil erosion are key factors in dryland environments. such phenomena are related not only to geoecological factors (lithology, topography, and climatology) but also to land-use and plant cover changes. formation of new sand dunes in damghan explains the development of human activities over the past. the aim of this study is to explain the land use changes and th...

Seepage in a medium packed with particles of variable granular size can be seen in many fields of engineering applications. Due to the relative complex spatial aspect of pore geometry, there are notable differences in the critical parameters of flow transition (Reynolds number and Forchheimer number) between different structures. It is difficult to distinguish the available range of seepage equ...

[1] We report on laboratory experiments designed to investigate the strength evolution and formation mechanisms of cataclastic deformation bands hosted in unlithified sand, with particular focus on the role of grain breakage. Cataclastic deformation bands are characterized by particle size reduction and increased resistance to weathering compared to parent material. We recovered bands intact fr...

This short communication discusses an algorithm suited for the generation of periodic microstructures of granular media. Its particular features are a user-defined grain size distribution, a representative volume element which is intrinsically periodic ab initio and a user-defined termination criterion, controlled by an increase of volume fraction. For low densities our particle packings resemb...

Particle breakage is of fundamental importance for understanding the mechanical behaviour of sands and is relevant to many geotechnical engineering problems. In order to gain new insights into the mechanism of breakage of individual sand particles under single-particle compression, this study combines mechanical tests with three-dimensional X-ray micro-computed tomography (μCT) performed ‘in si...