abstract in all river engineering projects, determination of flow resistance is essential. most commonly, the manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. over the past decades little or no study has been conducted to investigate the effects of particle shapes on manning roughness coefficient. therefore, it is the...

We investigate two published approaches to the problem of estimating fractal dimension: the box-counting approach, and the fractal Brownian function approach. In experiments with synthetic images, we find the fractal Brownian function methods proposed by Pentland and Yokoya to be superior to the box-counting approaches described by Voss, because the former do not require data sampled at equal i...

A map of extant slope failures is the most basic element of any landslide assessment. Without an accurate inventory of slope instability, it is not possible to analyze the controls on the spatial and temporal patterns of mass movement or the environmental, human, or geomorphic consequences of slides. Landslide inventory maps are tedious to compile, difficult to make in vegetated terrain using c...

This paper presents a methodology for motion planning in outdoor environments that takes into account specific characteristics of the terrain. Instead of decomposing the robot configuration space into “free” and “occupied”, we consider the existence of several regions with different navigation costs. Costs are determined experimentally by navigating the robot through the regions and measuring t...

Two important aspects of part inspection are the measurement of surface shape and surface roughness. We propose a noncontact method of measuring surface shape and surface roughness. The method, which we call “four light photometric stereo”, uses four lights which sequentially iUuminate the object under inspection, and a video camera for taking images of the object. Conceptually, the problem we ...

aeolian landforms are very sensitive to wind erosion. afforestation of degraded sandy land soils is regarded the most effective strategy against wind erosion. the aim of this study is to estimate decreasing in wind erosion rate by afforestation of these landforms. in this research, geomorphological areas have been used as homogeneous units. research data are including scores of petrology, terra...

39 This paper describes the computation and analysis of the Earth's short-scale gravity field 40 through high-resolution gravity forward modelling using the Shuttle Radar Topography 41 Mission (SRTM) global topography model. We use the established residual terrain modelling 42 technique along with advanced computational resources and massive parallelisation to 43 convert the high-pass filtered ...

Surface texturing is used to increase hydrodynamic pressure and reduce friction and wear between parallel sliding surfaces in a variety of applications. The shape, geometry, and density of the patterned microtexture features play a key role in the tribological performance of such textured slider bearings. Lubrication models are used to predict the load-carrying capacity, friction coefficient, a...

The topography of natural surfaces at scales of a few meters or less is commonly referred to as roughness. These variations in height and slope, their magnitude, and the changes in structure as a function of scale length are of fundamental importance to interpretation of geologic emplacement regimes and subsequent modification. For most planetary studies and many terrestrial situations, no in s...