background: deficiency of attention and concentration is one of great reasons of traffic incidents and it covers between 20 to 50 percent of events due to careless and mindedness. studies show that attention and concentration are considered as one of important cognitive components in safe driving. vibration is an important physical effect in all vehicles. till now has not been any organized stu...

The bulk of particulate transition metals transported by Patagonian rivers shows an upper crustal composition. Riverine particulate 0.5 N HCl leachable trace metal concentrations are mainly controlled by Fe-oxides. Complexation of Fe by dissolved organic carbon (DOC) appears to be an important determinant of the phases transporting trace metals in Patagonian rivers. In contrast, aeolian trace e...

[1] Landforms, morphologically similar to aeolian yardangs but formed by erosion of bedrock by currents on an estuarine rock platform, are described for the first time. The geometries of the “yardangs” are described and related to semi-lemniscate shapes that minimize hydraulic drag. The processes of bedrock erosion by the reversing sedimentladen tidal currents are described, and a semi-quantita...

Dust deposition lowers the albedo of snow and can significantly alter snowpack energy balance. Investigation of aeolian dust deposition in the mountains of the western U.S. has shown that these effects advance the timing of snowpack melt and spring runoff across much of the region. These studies have primarily focused on alpine snowpacks with little to no overstory vegetation. To evaluate the i...

[1] We use an ocean circulation, biogeochemistry, and ecosystem model to explore the interactions between ocean circulation, macroand micro-nutrient supply to the euphotic layer, and biological productivity. The model suggests a tight coupling between the degree of iron limitation in the upwelling subpolar and tropical oceans and the productivity of the adjacent subtropical gyres. This coupling...

kashan erg is one of the most important sand dunes complexes in iran. it is included the most important various type of sand dunes in iran. this study was performed to compare the granulometry of aeolian sediments in different sand dunes and also from plinth to crest of transverse dunes that located in kashan erg’s north. in order to determining different statistical variables, aeolian sediment...

In aeolian transport saltation is an important link by which momentum is transmitted from the air to the bed through grain impact, but momentum transfer, impact and subsequent entrainment take place in a very shallow layer at the air-bed interface with large velocity gradients. Consequently, experimental evidence on the impact-entrainment processes has been obtained from few and simplified stud...

Aeolian sand beds exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns...

This paper discusses the possibilities of laboratory simulation of large-scale flow around dunes, both with and without saltation, and the study of the physics of the small-scale particle motion occurring on a sand surface composed of like-moveable particles. Physics of the atmospheric boundary layer are presented in the context of laboratory applications. The governing equations of fluid and/o...

vibration generated by vehicles during road transport has an important impact on agricultural products' damage process, particularly in the case of fruits and vegetables. modulus of elasticity is one of the most conspicuous mechanical properties of fruits, the variation in which can be described as one of the most affecting damage criteria during transportation. this research was conducted...