Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by DEM simulation. In this article, a new approach was used to assess the main paramet...

interest rate ad valorem tariffs are considered as the most prominent trade tools extensively used in the framework of spatial equilibrium models (sems) to analyze agricultural and food trade policies around the world. however the results obtained from such models have been criticized because of their inadequacy in producing any observed data within the base period. hence a positive spatial and...

the objective of this study is evaluation of topographic wetness index (twi) using attraction model in northern of fars province. the first attraction model was used to enhance the spatial resolution of digital elevation model (dem). in this research to estimate of value of sub-pixels neighboring pixels, touching and quadrant neighboring models were used. after manufacturing output images for s...

We study the effect of particle cohesion on the steady state shear strength of a granular material. For cohesive powders, the steady state shear loci (termination loci) from DEM simulations are nonlinear with a peculiar pressure dependence due to the non-linear increase of contact adhesion with pressure in the contact model. Physical experiments are carried out on fine limestone powder in the d...

The paper is focused on the main limits to the performances of the DEM retrieval from SAR interferometry, measured in terms of horizontal resolution and vertical accuracy. A mathematical model is developed to assess the accuracy of the location in 3D, given the two SAR images and a set of calibrated references, or Ground Control Point, with known accuracy, whereas we assume that the geometry of...

Recent advances in calibration techniques have made calibrated SAR images, in which the data represents radar cross-section (0') or normalized radar cross-section (0'0), a reality. In this paper, some of these recent advances are discussed in the context of their impact on SAR sys'tem design, and in terms of the errors associated with each technique. The main sources of error in radiometric cal...

With begin of 2013 DEM production started with the generation of the Intermediate TanDEM-X DEM (IDEM) for selected science and commercial test sites. This paper gives an overview of the Intermediate DEM production that took place from end of 2012 until July 2013. It describes the DEM production process and the lessons learnt by the IDEM phase. Since autumn 2013 the final DEM generation has begu...