instability


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instability

1. tendency to variable or unpredictable behaviour
2. Physics a fast growing disturbance or wave in a plasma
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

instability

[‚in·stə′bil·əd·ē]
(control systems)
A condition of a control system in which excessive positive feedback causes persistent, unwanted oscillations in the output of the system.
(physics)
A property of the steady state of a system such that certain disturbances or perturbations introduced into the steady state will increase in magnitude, the maximum perturbation amplitude always remaining larger than the initial amplitude.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

instability

In a structure, the sudden loss of stiffness that limits its load-carrying capability, and in some cases results in the structure’s failure.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

instability

instabilityclick for a larger image
i. A state of the atmosphere in which a parcel of air will continue to rise, if for any reason, it is pushed up. Any instability in the atmosphere means turbulent conditions exist. The environmental lapse rate (ELR) in this case will be higher than both dry and saturated adiabatic lapse rates. Dry adiabatic lapse rate (DALR) is the rate of decrease of temperature with height of a parcel of dry air lifted adiabatically. Its value is 3°/1000 ft. Saturated adiabatic lapse rate (SALR) is the lapse rate of a parcel of saturated air and its value is 1.5°/1000 ft.
ii. A tendency of a body to continue moving away from its original state when disturbed by an external force and to continue after that force has been withdrawn.
iii. The failure of structures, such as the buckling of plates and panels under compression, and the failure of struts under end loads.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Chu, "Parametric instability in planetary gears with frequency-modulated time-varying mesh stiffness," in Proceedings of the ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2014, New York, NY, USA, 2014.
These contingencies are "armed confrontation in the South China Sea, renewed fighting in eastern Ukraine, and political instability in Nigeria due to Boko Haram activity."
Instability in production schedules can lead to undesirable outcomes (Pujawan, 2008; Kabak & Ornet, 2009).
To investigate the features of complex mine pressure manifestation on work faces, from the point of view of probability and statistics, we can assume that the instability of fractured blocks of overlying strata depends on some parameter X and the instability probability of fractured blocks is P(X).
"If you trigger this instability, you don't need to continue to force the ice sheet by cranking up temperatures.
They also demonstrated that the R-T-like instability can occur under a wide variety of gas flow and vibration conditions, forming different structures under different excitation conditions.
Obtaining a detailed history and performing an appropriate, focused physical examination are critical components to the diagnosis and workup of first-time shoulder instability. While the specific pathology of an injury greatly influence treatment, ideal management is also dictated by the characteristics of each individual patient.
Yamada's insights point to a link between chromosome instability and the development of Alzheimer's disease.
Young athletes with shoulder instability are considered to be a high-risk group of patients following arthroscopic shoulder stabilization, given the high recurrence rates and lower rates of return to sport.
Housing instability can hurt the health of both adults and children, a new study finds.
LAHORE -- Federal Interior Minister, Ahsan Iqbal has said that political stability is very important for boosting the economy of any country economy and adding that the prevailing political instability will harm the economy.