Global instability

In a strict sense, an advanced analysis" is one in which the nonlinear geometric and material effects are accounted for in the analysts of the structure as a whole in determining its ultimate load carrying capacity. In addition, effects of local as well as overall global instability are considered such that it is not necessary to evaluate individual members subsequent to the completion of the advanced analysts. In other words, all the appropriate limit state, design code requirements are incorporated into the analysts (White 1993, Chen 1994). 

A second and complimentary measure of lattice strain is the global instability index (GII) defined by Salinas-Sanchez et al. (1992) using eqn (12.2) ... 

Fig. 13.3. The phase diagram of Ao.33A o.67Mn03 (A = divalent cation, A = rare earth) as a function of temperature and the global instability index of the idealized perovskite structure. The points show the observed transition temperatures in various compounds. FMM = ferromagnetic metal, PMI = paramagnetic insulator, FMI = ferromagnetic insulator (from Rao et al. 1998).

Phenomena such as El Ninos or thermocline circulation in the North Atlantic lead to global instability in the processes of energy and matter exchange, which should be reflected by parameterizing non-linear feedbacks. 

MODERN SOCIETY AND ECOLOGICAL RESTRICTIONS 7.5.1 Global instability... 

Growing global instability has resulted in changes in the nature of international disaster relief efforts. The work effort in disaster relief has increased in its intensity and demand along with a serious increase in risks to the personal safety of international workers. These changes mandate that the preparation of health care workers (in this case nurses) needs to be as comprehensive as possible. It is essential that the individual be as prepared as possible for eventualities that may arise in what may be a potentially volatile and unpredictable environment. Equally, it is essential that the deploying nurse does not become a burden on his or her fellow workers in times of hardship and stress. 

Figure 3 The variation in the Global Instability Index of Ln2BaCu05 as a function of the ionic radius of Ln. The line is a fitted second order equation. Nd adopts a different structure. (Figure 12.3 from The Chemical Bond in Inorganic Chemistry by Brown, David (2001)). (Ref. 3. Reproduced by permission of Oxford University Press)...

More importantly, due to global instability, the price and availability of crnde oil can vary considerably from day to day. Waste fuels can help to solve some of the problems relating to environmental and economic issues which may lead to the shortage of safe fuel. Renewable or recycled fuels can help with ... 

A recent survey indicated Americans believe energy security should be a top priority of U.S. energy policy with wide support for a moon shot type of effort to develop a hydrogen economy. The dependence of the U.S. on oil creates a national security vulnerability that could result in widespread economic problems and increased global instabilities. 

Experiments are described using premixed prevaporized JP-10 in a dump combustor modified to accommodate counterflow control at the dump plane. The primary benefit of operation under prevaporized conditions is the careful regulation of the JP-lO/air stoichiometry, thereby providing independent assessment of flame speed modification using counterflow technology. Studies were also conducted to evaluate the fundamental nature of a planar nonreacting turbulent countercurrent shear layer. An abrupt transition in flow behavior at a counterflow level of U2/U1 w —0.13 provides the first evidence of global instability in a self-similar turbulent shear layer. 

Grinstein I sensed that you tried avoiding the use of the words global instability. Why ... 

Strykowski You indicate the presence of strong recirculation. Have you evaluated the impact of global instability concepts to the spray dynamics ... 

Gupta There is circumstantial evidence for global instability, but no hard evidence that we have identified. 

Huerre, P., and P. A. Monkewitz. 1990. Local and global instabilities in spatially developing flows. Annual Review Fluid Mechanics 22 473 537. 

Studies have shown that a high-speed gas jet, exiting a nozzle, will develop a large-scale orderly pattern as shown in Figure 8.23. This orderly structure is known as the "global instability" or "preferred mode" of the jet. The presence of both the small-scale turbulent eddies within the jet and the large-scale structure is responsible for the gas jet mixing noise. 

For characterization of the overall structure stability of perovskites, the Global Instability Index (GII), has been proposed (Salinas-Sanchez et al., 1992 Lufaso and Woodward, 2001). GII is defined as ... 

Physically, the onset of instabihty at the point is interpreted as the formation of crystal defect there. It should be noted that local instability does not imply global instability of the configuration. If angle between the vectors k and w established in this way is larger than 60°, then the nucleated defect is expected to be a dislocation with slip plane normal k and Burgers vector approximately along w. On the other hand, if the angle between k and w and instability is less than 30°, the nucleated defect would likely be a microcrack or a void. 

Liquefaction flow sUdes are one of the most catastrophic forms of ground failure. Flow failures often result in massive lateral and vertical movements of soil, occasionally for hundreds of meters laterally. While most commonly observed during earthquakes as a result of seismically induced liquefaction, flow failures also have occurred as a result of non-seismic (static) loading, displacements (i.e., shear strains) induced by global instability or creep, and dynamic loading. These failures are driven by static shear stresses that exceed the available shear resistance in the soil after the soil liquefies. The available shear... 

Structure Analysis and Prediction 11.1 The Global Instability Index... 

In the aristotype ABX3 perovskite stmcture, with Pm3m space group symmetry, there is a single free parameter, the cubic lattice parameter, a. A simple method to model the crystal stmcture is to determine the stmcture parameter(s), a in this case, that minimize(s) the Global Instability Index, G (Eq. (21) in [8]). 

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