scholarly journals A Theoretical MHD Model for Extragalactic Jets and its Comparison with the Observations

1990 ◽  
Vol 140 ◽  
pp. 441-442
Author(s):  
P. Pietrini
Keyword(s):  
Stability Analysis ◽  
Equilibrium Model ◽  
Stable Equilibrium ◽  
Point Of View ◽  
Observational Constraints ◽  
Radio Sources ◽  
Equilibrium Configurations ◽  
Extragalactic Jets ◽  
Thermal Confinement ◽  
The Stability

Two aspects of the MHD stationary equilibrium model developed by Chiuderi et al.(1989) to describe extragalactic jets are analyzed and compared with the observational constraints: the global energy flux convected by the cylindrical jet and the ranges of the equilibrium parameters allowed by the stability analysis. In particular, the results obtained from the temporal stability analysis are converted into a spatial point of view. In this context, it is easier to find essentially “stable” equilibrium configurations for shorter jets. In conclusion, the fundamental hypotheses of this model (like thermal confinement and substantial equipartition among the various forms of energy considered) are such that the model turns out to be suitable for the description of class I jets, associated with rather low-power radio sources.

scholarly journals On the alternative approaches to stability analysis in decision support for damaged passenger ships

2019 ◽  
Vol 18 (3) ◽  
pp. 477-494 ◽  
Author(s):  
Pekka Ruponen ◽  
Petri Pennanen ◽  
Teemu Manderbacka
Keyword(s):  
Decision Support ◽  
Stability Analysis ◽  
Decision Support System ◽  
Support System ◽  
Point Of View ◽  
Additional Information ◽  
Damage Stability ◽  
Passenger Ships ◽  
Minimum Requirements ◽  
The Stability

Abstract A decision support system with damage stability analysis has been recognized as an important tool for passenger ships. Various software applications have been developed and taken into use over the years, without a direct link to any compelling requirement, set forth in the international regulatory framework. After the Costa Concordia accident, new regulations have been established, setting minimum requirements for a decision support system, as an extension to a loading computer. Yet, more advanced systems have been developed recently, aiming at providing valuable additional information on the predicted development of the stability of the damaged ship. This paper presents these alternative decision support systems with damage stability analysis methods for flooding emergencies on passenger ships. The technical background, usability, and usefulness of the various approaches are compared and discussed, taking into account the important statutory approval point of view. In addition, practical examples, including past accidents, are presented and discussed.

scholarly journals Computational Stability Analysis of Lotka-Volterra Systems

2016 ◽  
Vol 44 (2) ◽  
pp. 113-120
Author(s):  
Péter Polcz ◽  
Keyword(s):  
Stability Analysis ◽  
Lyapunov Functions ◽  
Stability Region ◽  
Stable Equilibrium ◽  
Linear Matrix ◽  
Stable Equilibrium Point ◽  
Computational Stability ◽  
Volterra Systems ◽  
Selection For ◽  
The Stability

Abstract This paper concerns the computational stability analysis of locally stable Lotka-Volterra (LV) systems by searching for appropriate Lyapunov functions in a general quadratic form composed of higher order monomial terms. The Lyapunov conditions are ensured through the solution of linear matrix inequalities. The stability region is estimated by determining the level set of the Lyapunov function within a suitable convex domain. The paper includes interesting computational results and discussion on the stability regions of higher (3,4) dimensional LV models as well as on the monomial selection for constructing the Lyapunov functions. Finally, the stability region is estimated of an uncertain 2D LV system with an uncertain interior locally stable equilibrium point.

scholarly journals A Self-Similar Model for Extragalactic Jets and the FRI/FRII Divide

1997 ◽  
Vol 163 ◽  
pp. 732-733
Author(s):  
C.R. Kaiser ◽  
P. Alexander
Keyword(s):  
Large Scale ◽  
Life Time ◽  
Large Scale Structure ◽  
Radio Sources ◽  
Similar Model ◽  
Extragalactic Jets ◽  
Self Similar ◽  
The Stability ◽  
Jet Power ◽  
Good Agreement

AbstractWe present a model for the large scale structure of FRIItype extragalactic radio sources. The sources are shown to grow selfsimilar and the dependence of the length of the source and the pressure inside the cocoon on the life time are calculated. The stability of the jets in such sources is investigated and the jet power at which FRII sources turn into FRIs is found to be in good agreement with observations.

Stability of Dynamical Systems With Multiple Nonlinearities

1987 ◽  
Vol 109 (4) ◽  
pp. 410-413 ◽  
Author(s):  
Norio Miyagi ◽  
Hayao Miyagi
Keyword(s):  
Dynamical System ◽  
Stability Analysis ◽  
Dynamical Systems ◽  
Lyapunov Function ◽  
Stability Region ◽  
Direct Method ◽  
Essential Feature ◽  
Point Of View ◽  
Stability Of Dynamical Systems ◽  
The Stability

This note applies the direct method of Lyapunov to stability analysis of a dynamical system with multiple nonlinearities. The essential feature of the Lyapunov function used in this note is a non-Lure´ type Lyapunov function which surpasses the Lure´-type Lyapunov function from the point of view of the stability region guaranteed. A modified version of the multivariable Popov criterion is used to construct non-Lure´ type Lyapunov function, which allow for the dynamical sytems with multiple nonlinearities.

Stripe and Spot Patterns for General Gierer–Meinhardt Model with Common Sources

2017 ◽  
Vol 27 (02) ◽  
pp. 1750018 ◽  
Author(s):  
You Li ◽  
Jinliang Wang ◽  
Xiaojie Hou
Keyword(s):  
Periodic Solution ◽  
Stability Analysis ◽  
Hopf Bifurcation ◽  
Theoretical Analysis ◽  
Stable Equilibrium ◽  
Turing Instability ◽  
Turing Patterns ◽  
Stability Conditions ◽  
Ode System ◽  
The Stability

This paper focuses on the Turing patterns in the general Gierer–Meinhardt model of morphogenesis. The stability analysis of the equilibrium for the associated ODE system is carried out and the stability conditions are obtained. Furthermore, we perform a detailed Hopf bifurcation analysis for this system. The results show that the equilibrium undergoes a supercritical Hopf bifurcation in certain parameter range and the bifurcated limit cycle is stable. With added diffusions, we then show that both the stable equilibrium and the Hopf periodic solution experience Turing instability with unequal spatial diffusions and obtain the instability conditions. Numerical simulations are given to illustrate the theoretical analysis, which show that the Turing patterns are of either spot or stripe type.

Determination and Stability Analysis of Equilibrium Configurations of Objects Suspended From Multiple Aerial Robots

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Qimi Jiang ◽  
Vijay Kumar
Keyword(s):  
Stability Analysis ◽  
Hessian Matrix ◽  
Polynomial Equation ◽  
Search Algorithms ◽  
Cable System ◽  
Aerial Robots ◽  
Equilibrium Configurations ◽  
Position And Orientation ◽  
The Stability ◽  
Direct Kinematics

This work addresses the problem for determining the position and orientation of objects suspended with n cables from n aerial robots. This is actually the direct kinematics problem of the 3D cable system. First, the problem is formulated based on the static equilibrium condition. Then, an analytic algorithm based on resultant elimination is proposed to determine all possible equilibrium configurations of the planar 4-bar linkage. As the nonlinear system can be reduced to a polynomial equation in one unknown with a degree 8, this algorithm is more efficient than numerical search algorithms. Considering that the motion of a 3D cable system in its vertical planes of symmetry can be regarded as the motion of an equivalent planar 4-bar linkage, the proposed algorithm is used to solve the direct kinematics problem of objects suspended from multiple aerial robots. Case studies with three to six robots are conducted for demonstration. Then, approaches for stability analysis based on Hessian matrix are developed, and the stability of obtained equilibrium configurations is analyzed. Finally, experiments are conducted for validation.

Magnetic Belt Conveyor Running Stability Analysis

2013 ◽  
Vol 437 ◽  
pp. 682-685 ◽  
Author(s):  
Gang Cheng ◽  
Yong Cun Guo ◽  
Kun Hu ◽  
Peng Yu Wang
Keyword(s):  
Stability Analysis ◽  
Stable Equilibrium ◽  
Conveyor Belt ◽  
Point Of View ◽  
Magnetic Suspension ◽  
Maintenance Cost ◽  
Belt Conveyor ◽  
Stable Equilibrium State ◽  
Stability Calculation ◽  
Roller Support

Magnetic suspension type belt conveyor used magnetic machinery technology design can solve the belt conveyor of roller support parts number, large energy consumption and high maintenance cost, limited tape speed, large noise and other issues. Magnetic belt conveyor design is the key to stability analysis of the operation of conveyor belt. Papers from a mechanical point of view to study the structural stability calculation. The results show that small interfering in the external magnetic conveyor belt, the permanent support system can be adjusted to spontaneously stable equilibrium state.

scholarly journals Stability analysis of the Kosciuszko Mound using terrestrial laser scanner and numerical modelling

2018 ◽  
Vol 66 ◽  
pp. 01018
Author(s):  
Elżbieta Pilecka ◽  
Karolina Tomaszkiewicz
Keyword(s):  
Stability Analysis ◽  
Laser Scanner ◽  
Technical Condition ◽  
Point Of View ◽  
Terrestrial Laser Scanner ◽  
The Finite Element Method ◽  
Anthropogenic Soils ◽  
Differential Model ◽  
The Stability ◽  
Selection Of

Landslides which form in anthropogenic soils are complicated from a geological engineering and geotechnical point of view. Each case requires a detailed investigation and the selection of effective reinforcements is a difficult project issue. The study presents the problem of the stability analysis of landslides occurring in the anthropogenic soils of the Kosciuszko Mound in Cracow. The previously performed protections are discussed to highlight their ineffectiveness and the current technical condition of the mound is also presented. By overlapping the results of displacement measurements made with a terrestrial laser scanner, a differential model of the terrain was created which made it possible to determine the size and direction of the deformation of the slopes of the mound and the tendencies for the development of landslide movements in this area. A cross-section, selected on the basis of the model, was numerically analysed using the finite element method (FEM) in the Midas GTS NX program. As a result of the analysis, the values of the displacements and strains occurring in the Mound were calculated. On the basis of the value of the safety factor obtained, it was also possible to assess the risk of landslide movements.

scholarly journals Electrostatic Circular Membrane MEMS: An Approach to the Optimal Control

Computation ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 41
Author(s):  
Mario Versaci ◽  
Francesco Carlo Morabito
Keyword(s):  
Optimal Control ◽  
Stable Equilibrium ◽  
Equilibrium Configuration ◽  
Micro Electro Mechanical System ◽  
Circular Membrane ◽  
Differential Model ◽  
Equilibrium Configurations ◽  
Electrostatic Effect ◽  
The Mean ◽  
The Stability

The recovery of the membrane profile of an electrostatic micro-electro-mechanical system (MEMS) is an important issue, because, when an external electrical voltage is applied, the membrane deforms with the risk of touching the upper plate of the device producing an unwanted electrostatic effect. Therefore, it is important to know whether the movement admits stable equilibrium configurations especially when the membrane is closed to the upper plate. In this framework, this work analyzes the behavior of a two-dimensional (2D) electrostatic circular membrane MEMS device subjected to an external voltage. Specifically, starting from a well-known 2D non-linear second-order differential model in which the electrostatic field in the device is proportional to the mean curvature of the membrane, the stability of the only possible equilibrium configuration is studied. Furthermore, when considering that the membrane is equipped with mechanical inertia and that it must not touch the upper plate of the device, a useful range of possible values has been obtained for the applied voltage. Finally, the paper concludes with some computations regarding the variation of potential energy, identifying some optimal control conditions.

Stability Analysis of Oscillatory Systems Subject to Large Delays: A Synchronization Point of View

2010 ◽  
Vol 16 (7-8) ◽  
pp. 1087-1110 ◽  
Author(s):  
Wim Michiels
Keyword(s):  
Stability Analysis ◽  
Phase Synchronization ◽  
Linear Time ◽  
Point Of View ◽  
Feedback Stabilization ◽  
Delay Systems ◽  
Qualitative Behavior ◽  
Oscillatory Systems ◽  
Characteristic Roots ◽  
The Stability

The behavior of the rightmost characteristic roots of linear time-delay systems as a function of the delay parameter is studied for small values of a gain parameter. The results explain the qualitative behavior of the stability regions in the delay parameter space of oscillatory systems subjected to large delays, and shed new light on the corresponding stabilization problem. In particular, for a chain of multiple oscillators the determination of a stabilizing value of the delay parameter is interpreted as a phase synchronization problem. The results are illustrated with the output feedback stabilization of an oscillator and the stability analysis of a gyroscopic system.

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