On the dissipation processes in the oscillating system with a magneto-liquid element

2009 ◽  
Vol 45 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Krisztina Sebők-Nagy ◽  
László Biczók ◽  
Akimitsu Morimoto ◽  
Tetsuya Shimada ◽  
Haruo Inoue

2004 ◽  
Vol 82 (4) ◽  
pp. 291-301 ◽  
Author(s):  
J R Cahoon

A simple and absolute method for the calculation of the first coordination number for any pure, isotropic liquid element is presented. The liquid density and the position for the first peak of the radial distribution function, assumed to be the atomic diameter, are the only parameters required. The coordination number for liquid metals that exhibit a BCC (body-centred cube) solid structure averages 7.4 while the first coordination number for liquid metals with a FCC (face-centred cube) or CPH (close-packed hexagonal) solid structure averages 7.1. Those liquid elements that have less closed-packed solid structures have a first coordination number less than 7.0. The calculation also correctly predicts the first coordination number for liquid Se to be 2.4, consistent with its chain-like structure. The calculated values for the liquid element coordination numbers are consistent with the decrease in density of a few percent that occurs upon melting and appear to be related to the Engel–Brewer valence of the solid, which suggests that the electron structure of the solid may be retained upon melting. The first coordination numbers for liquid Ge and Si were calculated to be 5.0 and 4.7, respectively, larger than the value of 4.0 for solid structures. The increase in coordination number upon melting accounts for the increase in density of Ge and Si that occurs upon melting.PACS No.: 61.20.Gy


2021 ◽  
Author(s):  
Santiago Triana ◽  
Jeremy Rekier ◽  
Antony Trinh ◽  
Veronique Dehant ◽  
Ping Zhu

<p>The cause for the damping of the Earth's Free Core Nutation (FCN) and the Free Inner Core Nutation (FICN) eigenmodes has been a matter of debate since the earliest reliable estimations from nutation observations were made available. Numerical studies are difficult given the extreme values of some of the parameters associated with the Earth's fluid outer core, where important dissipation processes can take place. We present a linear numerical model for the FCN that includes viscous dissipation and Ohmic heating. We find an asymptotic regime, appropriate for Earth's parameters, where viscous and Ohmic processes contribute equally to the total damping, with the dissipation taking place almost exclusively in the boundary layers. By matching the observed nutational damping we infer an enhanced effective viscosity matching and validating methods from previous studies. We suggest that turbulence caused by the Earth's precession can be a source for the FCN's damping. </p>


2008 ◽  
Vol 516 (9) ◽  
pp. 2670-2676
Author(s):  
Mitsumasa Iwamoto ◽  
A.A. Vakulenko ◽  
A.V. Zakharov

Author(s):  
Elio Roca-Flores ◽  
Gerardo G. Naumis

The ranking of events is a powerful way to study the complexity of rare catastrophic events as earthquakes and hurricanes. Hurricane activity can be quantified by the annual accumulated cyclone energy index (ACE), which contains the information of the maximum sustained wind speed, duration and frequency of the tropical cyclone season. Here, the ranking of the Northeast Pacific annual ACE is obtained and fitted using nonlinear regression with several two- and three-parameter ranking laws that fit the tail and head of the data, where lives the information of relevant events for human society. The logarithmic like function [Formula: see text] overperforms all other fits. A sliding window analysis of the parameters [Formula: see text] and [Formula: see text] of such a function shows that forcing and dissipation processes are anticorrelated.


2009 ◽  
Vol 27 (9) ◽  
pp. 3645-3662 ◽  
Author(s):  
M. J. López-González ◽  
E. Rodríguez ◽  
M. García-Comas ◽  
V. Costa ◽  
M. G. Shepherd ◽  
...  

Abstract. The presence of planetary wave type oscillations at mid-latitudes in the mesosphere/lower thermosphere region has been investigated using airglow observations. The observations were taken with a Spectral Airglow Temperature Imager (SATI) installed at Sierra Nevada Observatory (37.06° N, 3.38° W) at 2900 m height. Airglow data of the column emission rate of the O2 Atmospheric (0-1) band and of the OH Meinel (6-2) band and deduced rotational temperatures from 1998 to 2007 have been used in this study. From these observations a climatology of planetary wave type oscillations at this location is inferred. It has been found that the planetary wave type oscillations of 5-day period is predominant in our data throughout the year, with activity greater than 50% during March/April and October/November months. The planetary wave type oscillations of 2-day period is predominant during both solstices, being predominant during winter solstice in O2 while a 10-day oscillation appears throughout the year with activity around 20% and with maximum activity during spring and autumn equinoxes. The 16-day oscillation has maximum occurrence during autumn-winter while its activity is almost disappeared during spring-summer. No clear seasonal dependence of the amplitude of the planetary wave type oscillations was observed in the cases considered in this study. The waves simultaneously detected in the rotational temperatures deduced from both OH and O2 emissions usually show an upward energy propagation and are affected by dissipation processes.


Sign in / Sign up

Export Citation Format

Share Document