uniaxial compressive strength (ucs) and internal friction coefficient (µ) are the most important strength parameters of rock. they could be determined either by laboratory tests or from empirical correlations. the laboratory analysis sometimes is not possible for many reasons. on the other hand, due to changes in rock compositions and properties, none of the correlations could be applied as an ...

the friction properties of granular materials play an important role in the determination of specifications for designing hoppers, transporting passages, dryers, silos and machines through which grain flows. in this study, the angle of repose and internal friction coefficient were determined for three common wheat varieties (sardary, gaspard and saysoter) at four moisture contents (12, 15, 18, ...

physical and mechanical properties of alfalfa (medicago sativa, l.) grind are required for optimum design of equipment used in transporting, processing and storage of the material. this study was conducted to determine the effect of particle size (2.38, 3.36 and 4.76 mm) and moisture content (8, 9.3 and 11% wb) on some physical and mechanical properties of alfalfa grind. these properties includ...

We analyze two- and three-link planar snakelike locomotion and optimize the motion for efficiency. The locomoting system consists of two or three identical inextensible links connected via hinge joints, and the angles between the links are actuated as prescribed periodic functions of time. An essential feature of snake locomotion is frictional anisotropy: The forward, backward, and transverse c...

The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction coefficient reveals strongly non-linear dependence on the cylinder’s velocity. For low velocity the rolling-friction coefficient rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity according t...

in this work, experimental studies of internal friction coefficient and porosity of four high productive rice varieties in iran (nemat, neda, pajouhesh and pardis) have been presented. moisture content varied in four different ranges between 8 and 20%. the obtained results indicated that the internal friction coefficient decreased with increasing the moisture content from 8 to 11%, then decreas...

An adaptive control scheme for emergency braking of vehicles is designed based on a LuGre dynamic model for the tire/road friction. The wheel angular speed and longitudinal vehicle acceleration information are used to design an observerestimator for vehicle velocity, friction internal state and friction parameters. A Lyapunov-based stabilizing controller is designed to achieve near maximum brak...

Nanosecond laser T-jump was used to measure the viscosity dependence of the folding kinetics of the villin subdomain under conditions where the viscogen has no effect on its equilibrium properties. The dependence of the unfolding/refolding relaxation time on solvent viscosity indicates a major contribution to the dynamics from internal friction. The internal friction increases with increasing t...

We report on detailed laboratory experiments designed to illustrate the frictional behavior of granular volcanic debris. The materials include pyroclastic flow debris from Soufrière Hills Volcano, Montserrat, and from Stromboli Volcano, Italy, and lahar deposits from Mount St. Helens. Experiments were conducted in a servo-controlled, double-direct shear apparatus under conditions of displacemen...

Internal friction (I.F.) and modulus measurements have been carried out as a function of temperature in order to study the Li mobility in an A1 8.1 at% Li 0.03 at% Zr alloy. The results show that the sequence of 6' and 6 precipitation can be followed through the evolution of the internal friction spectra. Two peaks appear in the internal friction spectrum. The low temperature peak Pz (450 K), h...