large areas of iran are under the influence of wind erosion thus it is important that we recognize three zones ofremoval, transportation and deposition. the deposition zone is very important due to more damages and tangibleeffects. in this study we try to obtain a comprehensive idea to persian desert with use of laboratory facilities, remotesensing, gis and field surveying. we survey 28 ergs in...

This doctoral thesis reports analytical and numerical results for the electrostatic response of a dusty plasma to a moving test charge. Two important physical aspects of dusty plasmas, namely grain size distribution and grain charging dynamics were taken into account. In the first case, a dusty plasma in thermal equilibrium and with a distribution of grain sizes is considered. A size distributi...

Natural bed topography and habitat is affected by the composition of gravels in various shapes and sizes. Traditional measurement methods for grain size distribution are time-consuming and labor-intensive. Recent advances in image processing techniques facilitate automated grain size measurement through digital images. This study introduces a refined automated grain sizing method (R-AGS) incorp...

The task of reconstruction of microstructures from their limited description is posed as a maximum entropy (MaxEnt) problem. Microstructural descriptors are taken in the form of volume fractions, correlation functions and grain sizes. Morphological and size quantifications are used as features of microstructure and samples consistent with these features are reconstructed. The nonuniqueness of t...

Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) have proved to be important structural ceramics. High strength and fracture toughness make them attractive candidates for a number of demanding applications. It was established that these advantageous properties are strongly influenced by the ceramic microstructure [1]. The relationships between microstructure and mechanical properties ...

The distribution of forest cover exerts strong controls on the spatiotemporal distribution of snow accumulation and snowmelt. The physical processes that govern these controls are poorly understood given a lack of detailed measurements of snow states. In this study, we address one of many measurement gaps by using contact spectroscopy to measure snow optical grain size at high spatial resolutio...

The material properties of sedimentary rocks are controlled by a range of parameters, including grain size, sorting, and modification of the original sediment through the diagenetic processes of compaction and cementation. To isolate the effects of diagenesis, and explore how they modify permeability, we quantified changes in grain and pore morphology accompanying progressive diagenesis of a si...

[1] Bed load sediment particles supplied to channels by hillslopes are reduced in size by abrasion during downstream transport. The branching structure of the channel network creates a distribution of downstream travel distances to a given reach of river and thus may strongly influence the grain size distribution of the long-term bed load flux through that reach. Here we investigate this hypoth...

In this paper, a multiscale modelling strategy is used to study the effect of grain-boundary sliding on stress localization in a polycrystalline microstructure with an uneven distribution of grain size. The development of the molecular dynamics (MD) analysis used to interrogate idealized grain microstructures with various types of grain boundaries and the multiscale modelling strategies for mod...

Abstract Microstructural characterisation of engineering materials is required for understanding the relationships between microstructure and mechanical properties. Conventionally grain size measured from boundary maps obtained using optical or electron microscopy. This paper implements EBSD-based linear intercept measurement spatial variation ferritic steel weld metals, making analysis flexibl...