Using low-stress pseudoshear deformation, we measured the ambient-temperaturecreep-recovery behavior of polycrystalline indium. The &+J diagram shows three regions with increasing stress: stress exponents of 1.05, 7.4, and 2.0. The diagram resembles remarkably the dislocation-velocity-shear-stressdiagrams reported for various materials by many authors, who interpreted the diagrams by dislocatio...

Macroscopic objects are usually manipulated by force and observed with light. On the nanoscale, however, this is often done oppositely: individual macromolecules are manipulated by light and monitored with force. This procedure, which is the basis of single-molecule force spectroscopy, has led to much of our quantitative understanding of how DNA works, and is now routinely applied to explore mo...

We consider biofilaments-flexible multimolecule structures common in cell biology-and show how "internal" friction associated with either conformational fluctuations or with fluid flow through narrow pores inside the filaments can dominate the external hydrodynamic friction usually considered to be the main energy dissipation process. The signature of this is wave-number-independent relaxation ...

A new approach is proposed to evaluate the non-limit active earth pressure in c–? soil based on horizontal slices method and limit equilibrium method, which takes into account arching effect, displacement, mobilized friction angle, tension cracks, shear stress of layer. The accuracy was demonstrated by comparing experimental results other theoretical methods. comparison showed that appropriate ...

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...

A novel observer structure for vehicle side slip angle (β ) estimation is proposed, in which a local approximation of the nonlinear tire model is adopted. Fuzzy logic approach is adopted to combine the local observer models so as to deal with the nonlinear nature of vehicle dynamics. The derivation of observer’s state equations and the estimation mechanism is developed. By choosing the membersh...

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...

We report the first measurements of friction angles for a naturally formed gravel streambed. For a given test grain size placed on a bed surface, friction angles varied from 10" to over 100'; friction angle distributions can be expressed as a function of test grain size, median bed grain size, and bed sorting parameter. Friction angles decrease with increasing grain size relative to the median ...