PHASE INSTABILITIES OF DISTORTED HEXAGONAL PATTERNS

2001 ◽  
Vol 11 (11) ◽  
pp. 2771-2777
Author(s):  
B. PEÑA ◽  
C. PÉREZ–GARCÍA
Keyword(s):  
Analytical Study ◽  
Full Range ◽  
Amplitude Equation ◽  
Phase Equation ◽  
Stability Regions ◽  
The Stability ◽  
Phase Instabilities

We present an analytical study on the stability of distorted hexagonal patterns. From a general amplitude equation we calculate the instabilities with respect to homogeneous and longwave perturbations. The latter lead to the phase equations that permit to determine the stability regions. Slightly squeezed hexagons are locally stable in a full range of distortion angles. The stability regions obtained from the phase equation are similar to those obtained numerically by other authors [Gunaratne et al., 1994].

scholarly journals Fast-Scale Instability and Stabilization by Adaptive Slope Compensation of a PV-Fed Differential Boost Inverter

2021 ◽  
Vol 11 (5) ◽  
pp. 2106
Author(s):  
Abdelali El Aroudi ◽  
Mohamed Debbat ◽  
Mohammed Al-Numay ◽  
Abdelmajid Abouloiafa
Keyword(s):  
Numerical Simulations ◽  
Full Range ◽  
Weather Conditions ◽  
Current Loop ◽  
Point Tracking ◽  
Bifurcation Phenomena ◽  
Slope Compensation ◽  
Power Point ◽  
The Stability ◽  
Detailed Circuit

Numerical simulations reveal that a single-stage differential boost AC module supplied from a PV module under an Maximum Power Point Tracking (MPPT) control at the input DC port and with current synchronization at the AC grid port might exhibit bifurcation phenomena under some weather conditions leading to subharmonic oscillation at the fast-switching scale. This paper will use discrete-time approach to characterize such behavior and to identify the onset of fast-scale instability. Slope compensation is used in the inner current loop to improve the stability of the system. The compensation slope values needed to guarantee stability for the full range of operating duty cycle and leading to an optimal deadbeat response are determined. The validity of the followed procedures is finally validated by a numerical simulations performed on a detailed circuit-level switched model of the AC module.

A Quasiperiodic Mathieu Equation

1995 ◽  
Author(s):  
Richard Rand ◽  
Rachel Hastings
Keyword(s):  
Numerical Integration ◽  
Mathieu Equation ◽  
Stability Regions ◽  
Regions Of Stability ◽  
Extensive Computation ◽  
The Stability ◽  
Direct Numerical Integration

Abstract In this work we investigate the following quasiperiodic Mathieu equation: x ¨ + ( δ + ϵ cos ⁡ t + ϵ cos ⁡ ω t ) x = 0 We use numerical integration to determine regions of stability in the δ–ω plane for fixed ϵ. Graphs of these stability regions are presented, based on extensive computation. In addition, we use perturbations to obtain approximations for the stability regions near δ=14 for small ω, and we compare the results with those of direct numerical integration.

scholarly journals THE PROBLEMS OF BRINGING RUSSIAN TRADE POLICY IN LINE WITH WTO REQUIREMENTS

2013 ◽  
pp. 146-152
Author(s):  
M. A. Petrova
Keyword(s):  
Trade Policy ◽  
Automotive Industry ◽  
New Technologies ◽  
Full Range ◽  
Economic Security ◽  
The European Union ◽  
Trade Dispute ◽  
National Economic ◽  
The Stability ◽  
Economic Zones

The article analyzes the role of trade policy in ensuring the competitiveness of the automotive industry – one of the most sensitive to the changes of economic conditions and important for providing national economic security – and finding a balance between the need to regulate the internal market and the implementation of the commitments under WTO. The analyze of the current condition of the Russian automotive industry has shown that, despite the low share in the world production and exports, Russia has a great potential for growth, mainly due to the unsaturated domestic market. It is proved, that the development of the automotive industry as one of the innovative industries in the country has all the necessary terms. Moreover, the priority areas for the development of the automotive industry include, first of all, the creation of a full range production with foreign investment. Measures of attracting and regulating FDI received much attention due to their relationship with the instruments of trade policy, as the production of capital goods, particularly automobiles, require imports of components, and FDI, in turn, promote the export of finished products. The commitments taken by Russia in the automotive industry include reduction of duties on imported cars, the renegotiation of investment programs and rules for the functioning of special economic zones. At present, the most acute question is car recycling tax, which has led to a trade dispute with the European Union, and may lead to countervailing measures against Russian goods. Considering WTO rules, recommendations on the use of the most effective instruments of foreign policy, aimed at improving the competitiveness of the Russian automotive industry, were made, including the rationalization of import and the attraction of new technologies due to the diversification of customs duties on certain groups of automotive components, lowering income taxes, a gradual decrease of the fiscal functions of the customs tariff; the stability and transparency of the instruments of trade policy and simplification of customs procedures.

scholarly journals LOCATION AND STABILITY OF THE TRIANGULAR POINTS IN THE TRIAXIAL ELLIPTIC RESTRICTED THREE-BODY PROBLEM

2021 ◽  
Vol 57 (2) ◽  
pp. 311-319
Author(s):  
M. Radwan ◽  
Nihad S. Abd El Motelp
Keyword(s):  
Linear Stability ◽  
Periodic Orbits ◽  
Body Problem ◽  
Restricted Three Body Problem ◽  
Three Body Problem ◽  
Stability Regions ◽  
Triangular Points ◽  
Problem Frame ◽  
The Stability ◽  
Three Body

The main goal of the present paper is to evaluate the perturbed locations and investigate the linear stability of the triangular points. We studied the problem in the elliptic restricted three body problem frame of work. The problem is generalized in the sense that the two primaries are considered as triaxial bodies. It was found that the locations of these points are affected by the triaxiality coefficients of the primaries and the eccentricity of orbits. Also, the stability regions depend on the involved perturbations. We also studied the periodic orbits in the vicinity of the triangular points.

scholarly journals The General Factor of Psychopathology

2020 ◽  
Vol 16 (1) ◽  
pp. 75-98 ◽  
Author(s):  
Gregory T. Smith ◽  
Emily A. Atkinson ◽  
Heather A. Davis ◽  
Elizabeth N. Riley ◽  
Joshua R. Oltmanns
Keyword(s):  
Mental Health Treatment ◽  
Full Range ◽  
Empirical Support ◽  
Strong Relationship ◽  
General Factor ◽  
General Factor Of Personality ◽  
The Stability ◽  
The Many ◽  
P Factor ◽  
Empirical Approaches

An important advance in understanding and defining mental disorders has been the development of empirical approaches to mapping dimensions of dysfunction and their interrelatedness. Such empirical approaches have consistently observed intercorrelations among the many forms of psychopathology, leading to the identification of a general factor of psychopathology (the p factor). In this article, we review empirical support for p, including evidence for the stability and criterion validity of p. Further, we discuss the strong relationship between p and both the general factor of personality and the general factor of personality disorder, substantive interpretations of p, and the potential clinical utility of p. We posit that proposed substantive interpretations of p do not explain the full range of symptomatology typically included in p. The most plausible explanation is that p represents an index of impairment that has the potential to inform the duration and intensity of a client's mental health treatment.

Theoretical Study on Instability Boundary of Rotor-Hydrodynamic Bearing Systems: Part II — Rotor With External Flexible Damped Support

2001 ◽  
Author(s):  
Zenglin Guo ◽  
R. Gordon Kirk
Keyword(s):  
Analytical Study ◽  
Theoretical Study ◽  
System Stability ◽  
Hydrodynamic Bearing ◽  
System A ◽  
Vertical Rotor ◽  
Speed Range ◽  
Stability Maps ◽  
Alternative Means ◽  
The Stability

Abstract The situation of a rotor-hydrodynamic bearing system in external flexible damped support is more complicated than that discussed before in Part I but it can become an alternative means to improve the stability of the rotor system. A model for both vertical and horizontal analysis is built first. Then, the analytical study on the vertical rotor is conducted. The results show that there might be up to four threshold speeds in this configuration that form a consecutive regional pattern taken turns by stable or unstable regions. Furthermore, the numerical calculation by MATLAB is carried out to obtain the results of the horizontal system. The stability maps for various parametric configurations are presented. It has been shown that the value of support damping has a strong effect on the first several lower threshold speeds. But it has little effect on the last top threshold speed which is mainly determined by the portion of journal mass. Within a certain range of external damping value, the first several regions of instability can be reduced or eradicated. As far as the entire stability map is concerned, there is an optimum range of value for support damping that can make the rotor have only one top threshold speed over the entire running speed range. When the support stiffness is increased, the system stability map becomes narrow which means a small support stiffness is good for broadening the range of optimum external damping.

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