scholarly journals Looking for Changes in the Saturnian System Between Voyager and Cassini

1992 ◽  
Vol 152 ◽  
pp. 53-64
Author(s):  
Nicole Borderies
Keyword(s):  
Ring System ◽  
Time Dependent ◽  
Planetary Rings ◽  
Small Satellites ◽  
Irregular Structures ◽  
Saturnian System ◽  
Long Time ◽  
Recession Rates ◽  
F Ring

This paper reviews a number of time-dependent phenomena that are relevant to our understanding of the dynamics of planetary rings and that will be investigated using Voyager and Cassini data. A long time baseline may help us decipher the physics of the spokes, understand better the morphology of the F ring and the rigid precession of non-circular ringlets, measure more precisely than has been done so far the satellites' torques and the viscosity of the A ring, and discover small satellites in the Saturnian ring system. Two exciting possibilities are those of determining the recession rates of the small satellites that border the rings, and of observing changes due to viscous diffusion in the irregular structures of the B ring.

The origin of planetary rings

1981 ◽  
Vol 303 (1477) ◽  
pp. 261-279 ◽  
Keyword(s):  
Outer Edge ◽  
Planetary Rings ◽  
Marked Variation ◽  
Saturnian System ◽  
Horseshoe Orbits ◽  
Sharp Edges ◽  
F Ring ◽  
The Stability ◽  
Narrow Ring

Recent spacecraft and ground-based observations have revealed the presence of narrow rings encircling the planets Jupiter, Saturn and Uranus. The Jovian ring is known to contain at least two small, dark, satellites of diameter between 20 and 40 km in its outer edge. The structure of the Saturnian F ring has been resolved by Voyager 1 and appears to be determined by the action of two small neighbouring satellites which were also imaged by the spacecraft. All nine Uranian rings are extremely narrow and some are appreciably eccentric. The outer 6 ring has very sharp edges and its radial width increases from 20 km at pericentre to 100 km at apocentre. This marked variation in width is also characteristic of the Uranian a and |3 rings and of a narrow ring in the Saturnian system. The structure of the Uranian rj ring is complex and may be similar to that of the Saturnian F ring. The resolution of the numerous, but well defined dynamical problems posed by these narrow rings must precede any discussion of the origin of rings. Two co-orbital Saturnian satellites that appear to move in horseshoe orbits have been discovered. The stability of these orbits and the origin of these and other co-orbital satellites are discussed.

scholarly journals Integrable unsteady motion with an application to ocean eddies

1998 ◽  
Vol 5 (3) ◽  
pp. 145-151
Author(s):  
A. D. Kirwan, Jr. ◽  
B. L. Lipphardt, Jr.
Keyword(s):  
Potential Vorticity ◽  
Particle Motion ◽  
Gulf Stream ◽  
Incompressible Flows ◽  
Unsteady Motion ◽  
Ring System ◽  
Time Dependent ◽  
Two Dimensional ◽  
Ocean Eddies ◽  
Multilayered Systems

Abstract. Application of the Brown-Samelson theorem, which shows that particle motion is integrable in a class of vorticity-conserving, two-dimensional incompressible flows, is extended here to a class of explicit time dependent dynamically balanced flows in multilayered systems. Particle motion for nonsteady two-dimensional flows with discontinuities in the vorticity or potential vorticity fields (modon solutions) is shown to be integrable. An example of a two-layer modon solution constrained by observations of a Gulf Stream ring system is discussed.

scholarly journals ANALYSIS OF THE TIME‐DEPENDENT BEHAVIOUR OF COMPOSITE CROSS‐SECTIONS BY LAPLACE‐TRANSFORM

2005 ◽  
Vol 11 (3) ◽  
pp. 203-209
Author(s):  
Erich Raue ◽  
Thorsten Heidolf
Keyword(s):  
Laplace Transform ◽  
Cross Sections ◽  
Composite Structures ◽  
Time Dependent ◽  
Time Interval ◽  
Final State ◽  
Long Time ◽  
Time Dependent Behaviour ◽  
Linear Differential ◽  
Dependent Behaviour

Composite structures consisting of precast and cast in‐situ concrete elements are increasingly common. These combinations demand a mechanical model which takes into account the time‐dependent behaviour and analysis of the different ages of the connected concrete components. The effect of creep and shrinkage of the different concrete components can be of relevance for the state of serviceability, as well as for the final state. The long‐time behaviour of concrete can be described by the rate‐of‐creep method, combined with a discretisation of time. The internal forces are described for each time interval using a system of linear differential equations, which can be solved by Laplace‐transform.

scholarly journals Time-dependent attractor of wave equations with nonlinear damping and linear memory

2019 ◽  
Vol 17 (1) ◽  
pp. 89-103
Author(s):  
Qiaozhen Ma ◽  
Jing Wang ◽  
Tingting Liu
Keyword(s):  
Wave Equation ◽  
Wave Equations ◽  
Nonlinear Damping ◽  
Time Dependent ◽  
Time Behavior ◽  
Long Time Behavior ◽  
Long Time

Abstract In this article, we consider the long-time behavior of solutions for the wave equation with nonlinear damping and linear memory. Within the theory of process on time-dependent spaces, we verify the process is asymptotically compact by using the contractive functions method, and then obtain the existence of the time-dependent attractor in $\begin{array}{} H^{1}_0({\it\Omega})\times L^{2}({\it\Omega})\times L^{2}_{\mu}(\mathbb{R}^{+};H^{1}_0({\it\Omega})) \end{array}$.

Synthesis and Biological Activity of the C′D′E′F′ Ring System of Maitotoxin

2014 ◽  
Vol 79 (11) ◽  
pp. 4948-4962 ◽  
Author(s):  
Masahiro Kunitake ◽  
Takahiro Oshima ◽  
Keiichi Konoki ◽  
Makoto Ebine ◽  
Kohei Torikai ◽  
...  
Keyword(s):  
Biological Activity ◽  
Ring System ◽  
F Ring

Dynamics for a plate equation with nonlinear damping on time-dependent space

2021 ◽  
pp. 1-17
Author(s):  
Penghui Zhang ◽  
Lu Yang
Keyword(s):  
Nonlinear Damping ◽  
Time Dependent ◽  
Time Behavior ◽  
Long Time Behavior ◽  
Plate Equation ◽  
Long Time

In this paper, we study the long-time behavior of the following plate equation ε ( t ) u t t + g ( u t ) + Δ 2 u + λ u + f ( u ) = h , where the coefficient ε depends explicitly on time, the nonlinear damping and the nonlinearity both have critical growths.

Long-Time Solutions to Heat-Conduction Transients with Time-Dependent Inputs

1980 ◽  
Vol 102 (1) ◽  
pp. 115-120 ◽  
Author(s):  
H. T. Ceylan ◽  
G. E. Myers
Keyword(s):  
Heat Conduction ◽  
Lower Cost ◽  
Piecewise Linear ◽  
Three Dimensional ◽  
Linear Functions ◽  
Time Dependent ◽  
Time Interval ◽  
Piecewise Linear Functions ◽  
One Dimensional ◽  
Long Time

An economical method for obtaining long-time solutions to one, two, or three-dimensional heat-conduction transients with time-dependent forcing functions is presented. The conduction problem is spatially discretized by finite differences or by finite elements to obtain a system of first-order ordinary differential equations. The time-dependent input functions are each approximated by continuous, piecewise-linear functions each having the same uniform time interval. A set of response coefficients is generated by which a long-time solution can be carried out with a considerably lower cost than for conventional methods. A one-dimensional illustrative example is included.

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