A lubricant for tidal friction

Tidal Friction and Tidal Lagging. Applicability Limitations of a Popular Formula for the Tidal Torque

Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies’ tidal despinning and also participate in the subtle process of entrapment of these bodies into spin–orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be bui...

The Equilibrium-Tide Model for Tidal Friction

We derive from first principles equations governing (a) the quadrupole tensor of a star distorted by both rotation and the presence of a companion in a possibly eccentric orbit, (b) a functional form for the dissipative force of tidal friction, based on the concept that the rate of energy loss from a time-dependent tide should be a positive-definite function of the rate of change of the quadrup...

Semidiurnal Tidal Motions in the Friction Layer

The obscrved semidiurnal wind in the troposphere at five niid-latmit,ude stations shows a, phase lead over the wind dcduccd from frictionlcss theory, and a smaller amplitude, espccially near the earth’s surface, than the theoretical value. By making use of the obscrved fact that the tidal pressure-dependent (frictionless) wind changes much less rapidly with height than does the observed wiiid i...

Cryogenic friction behavior of PTFE based solid lubricant composites

Solid lubricants used in aerospace applications must provide low friction and a predictable operation life over an extreme range of temperatures, environments and contact conditions. PTFE and PTFE composites have shown favorable tribological performance as solid lubricants. This study evaluates the effect of temperature on the friction coefficient of neat PTFE, a PTFE/ PEEK composite and an exp...

Development, Characterization and Simulation of Low-friction Boundary Lubricant Funcationalized Hydrogels for Use as a Low Friction Cartilage