64 research outputs found
Ridge Formation and De-Spinning of Iapetus via an Impact-Generated Satellite
We present a scenario for building the equatorial ridge and de-spinning
Iapetus through an impact-generated disk and satellite. This impact puts debris
into orbit, forming a ring inside the Roche limit and a satellite outside. This
satellite rapidly pushes the ring material down to the surface of Iapetus, and
then itself tidally evolves outward, thereby helping to de-spin Iapetus. This
scenario can de-spin Iapetus an order of magnitude faster than when tides due
to Saturn act alone, almost independently of its interior geophysical
evolution. Eventually, the satellite is stripped from its orbit by Saturn. The
range of satellite and impactor masses required is compatible with the
estimated impact history of Iapetus.Comment: 19 pages, 3 figures; Icarus, in pres
Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited
This report is a review of Darwin's classical theory of bodily tides in which
we present the analytical expressions for the orbital and rotational evolution
of the bodies and for the energy dissipation rates due to their tidal
interaction. General formulas are given which do not depend on any assumption
linking the tidal lags to the frequencies of the corresponding tidal waves
(except that equal frequency harmonics are assumed to span equal lags).
Emphasis is given to the cases of companions having reached one of the two
possible final states: (1) the super-synchronous stationary rotation resulting
from the vanishing of the average tidal torque; (2) the capture into a 1:1
spin-orbit resonance (true synchronization). In these cases, the energy
dissipation is controlled by the tidal harmonic with period equal to the
orbital period (instead of the semi-diurnal tide) and the singularity due to
the vanishing of the geometric phase lag does not exist. It is also shown that
the true synchronization with non-zero eccentricity is only possible if an
extra torque exists opposite to the tidal torque. The theory is developed
assuming that this additional torque is produced by an equatorial permanent
asymmetry in the companion. The results are model-dependent and the theory is
developed only to the second degree in eccentricity and inclination
(obliquity). It can easily be extended to higher orders, but formal accuracy
will not be a real improvement as long as the physics of the processes leading
to tidal lags is not better known.Comment: 30 pages, 7 figures, corrected typo
System Identification of a Non-Uniformly Sampled Multi-Rate System in Aluminium Electrolysis Cells
Evaluation of Analytical Methods to Determine Regulatory Compliance of Coffee Leaf Tea
The leaves of the coffee plant Coffea are traditionally used in several countries worldwide to prepare tea-like beverages using aqueous infusion in hot water. There are currently no tested methods available to check the regulatory compliance of coffee leaf tea according to the European Union (EU) novel food authorization. This study shows that standard ISO methods for tea analysis could be transferred without modifications to coffee leaf tea analysis. The only difference found was a much lower content of some catechins in coffee leaf tea compared to Camellia sinensis tea, but the methods were clearly applicable for use in controlling the EU’s maximum limits for coffee leaf tea
"Pfälzer Westrich" : conception for a touristic regionalization, development and marketing of a geographic region
Konzeption zur touristischen Regionalisierung eines semi-peripheren Raumes auf der Basis einer geo-historischen Landeskunde, Stärken-Schwächenanalyse, Tourismusmodule, Tourismusentwicklung und Maßnahmenkatalog sowie Synthesen, Visionen zu Nachbarregionen des "Europäischen Westrichs" : Ideen zur Förderung, Profilierung und Entwicklung eines ländlich strukturierten Raumes.Conception for the touristic regionalization of a semi-peripheral space based on geo-historical regional studies, strengths-weakness-analysis, tourism modules, tourism development and measurement-catalog as well as syntheses, visions to neighbour regions of the "European Westrich": Ideas to the support, image and development of a rurally structured geographic space
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