scholarly journals A Basic Study on Long-period Motion of a Moored Ship

2010 ◽  
Vol 122 (0) ◽  
pp. 195-200
Author(s):  
Toshio ISEKI ◽  
Daisuke KAWAMURA

We consider Earth satellites in the region where the perturbing effects due to Earth’s oblateness and luni-solar gravitational forces are comparable. A general solution is obtained for simultaneous precession about any number of fixed axes; this is an extension of Laplace’s treatment for the motion of Iapetus about Saturn. Results are given for general orbits on the assumption that the lunar orbit lies in the ecliptic. Synchronous orbits are considered in greater detail.


1935 ◽  
Vol 25 (1) ◽  
pp. 62-80 ◽  
Author(s):  
Perry Byerly

Summary The P travel-time curve of the Nevada earthquake is presented. It is drawn as a series of straight lines. It is near Δ = 28° that the data outline most clearly the sudden change in slope of the curve, but definite evidence of overlapping of the branches is lacking. At Δ = 67° (approximately) the curve branches into two parts as did the curve of the Texas earthquake. Between 4° and 12° three parallel P curves are drawn. The suggested explanation of them is that they are due to transformations of an original P or S at boundaries near the focus. This would indicate a depth of focus of about fifteen kilometers. The nature of the first motion at the various stations shows a complex distribution which does not lead to a simple explanation of the forces acting at the focus. A long-period component of P waves is observed, and it is concluded that it is present from very near the beginning of the record, although often masked by shorter-period motion. It begins in opposite phase to the shorter-period motion accompanying it.


1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.


1977 ◽  
Vol 36 ◽  
pp. 69-74

The discussion was separated into 3 different topics according to the separation made by the reviewer between the different periods of waves observed in the sun :1) global modes (long period oscillations) with predominantly radial harmonic motion.2) modes with large coherent - wave systems but not necessarily global excitation (300 s oscillation).3) locally excited - short period waves.


Author(s):  
A. Baronnet ◽  
M. Amouric

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.


Author(s):  
S. Shinozaki ◽  
J. W. Sprys

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.


Sign in / Sign up

Export Citation Format

Share Document