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We investigate viscous dissipation in linear flows driven by small-amplitude longitudinal librations in rotating fluid spheres focusing on the rapid rotation regime applicable to planets. Viscous coupling can resonate with inertial modes in the bulk of the fluid when the frequency of the forcing is within the range $(0,2\Omega _0)$, where $\Omega _0$ is the mean angular velocity of the sphere. We solve the linearised equations of motion with a semi-spectral numerical method and with an asymptotic expansion exploiting the small Ekman number, $E$, which quantifies the strength of viscous forces relative to the Coriolis force. Our results confirm that the dominant contribution to the dissipation occurs in the Ekman boundary layer with leading-order scaling $E^{1/2}$. When the forcing frequency coincides with that of an inertial mode, dissipation is reduced by as much as 9 % compared with boundary layer theory alone. The percentage-wise reduction is independent of $E$ and the frequency width of the reduction envelope scales as $E^{1/2}$. At non-resonant frequencies conic shear layers develop in the bulk interior and, together with the Ekman layer bulge at critical latitude, slightly enhance dissipation. We confirm critical latitude bulge and shear layer contributions to the overall dissipation scale as $E^{4/5}$ and $E^{6/5}$ respectively, becoming negligible compared with dissipation in the main boundary layer as $E\rightarrow 0$. The frequencies at which the dissipation enhancement from critical latitude effects is maximised are displaced from the inviscid limit periodic orbit frequencies by a factor that scales with $E^{0.23}$.
This chapter examines the way in which the international organized cooperative movement tried during the 1990s to make the connection between values and principles. The last revision of the principles, in the 1990s, differed from the earlier approaches because the International Co-operative Alliance (ICA) tried to situate the principles within the context of basic values. The origins of this effort can be traced back to 1978, when delegates to the ICA's Copenhagen Congress wondered if their movement was speaking effectively to modern circumstances. The sources for the cooperative values are very complex, derived from history, many community situations, cultural understandings, bodies of thought, and economic circumstances. The initial work of the 1990s demonstrated that there are commonalities in the values accepted throughout the international movement. Values emerge from reflections about lived experiences, and people and groups with similar convictions can naturally develop different degrees of emphasis on what they believe.
Trevisker pottery is a common Bronze Age type in Cornwall and the southwest of England. It is often well-made and with a distinct petrology. It was, however, traded in prehistory with some petrologically similar vessels being found in Brittany and northern France. Recently, a Cornish-style vessel made from Cornish clays has been located in eastern Kent, almost 500 km from its source.
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