Temporary instability

Temporary instability of rock storage areas is another potential hazard. Often these moimds are dumped by marine plant or lorries prior to placing in the works. As the rock in these storage areas has not been placed to any specification then the... 

Where there is the possibility of temporary instability, this should be designed out of the construction process. 

Rock dumping -temporary instability Can the rock storage areas be made secure and operators and the public be made aware of the risks ... 

Avoiding designs which involve temporary instability during erection... 

The hazards to be considered and controlled during the steel erection process include falls of people and material, the potential for structural collapse through temporary instability, the manual handling and slinging of the steelwork, and the means of lifting it into place. 

During studies directed towards the synthesis of spatol, Salomon and Murthi studied epoxysilane 153 bearing a temporary tether (Scheme 5.36), which circumvented the potential problem of configurational instability described above [57]. 

Once a particular class of unit has been decided upon, the choice of a specific unit depends on initial and operating costs, the space available, the type and size of the product, the characteristics of the feed liquor, the need for corrosion resistance and so on. Particular attention must be paid to liquor mixing zones since the circulation loop includes many regions where flow streams of different temperature and composition mix. These are all points at which temporary high supersaturations may occur causing heavy nucleation and hence encrustation, poor performance and operating instabilities. As Toussaint and Donders(72) stresses, it is essential that the compositions and enthalpies of mixer streams are always such that, at equilibrium, only one phase exists under the local conditions of temperature and pressure. 

Finding 17. The introduction of new structural risks during closure operations is a potential source of accidents. Dismantlement and removal of building structural components, such as the concrete floors of the explosion containment rooms, could pose added risks of structural instability during closure operations, as could temporary loadings from stacked materials or heavy equipment. 

Water electrolysis is usually carried out at constant current so that the performance of electrocatalysts should be constantly stable. Nevertheless, it has been shown that shutdown of cells in alkaline electrolysis results in the temporary dissolution of Ni cathodes. This implies that any variation of the electrolysis regime results in weakening of the resistance of materials to aggressive conditions. In other words, perturbations in the conditions of electrolysis are responsible for the appearance and the growth of the instability [cf AVt in Equation (7.16)]. 

In adiabatically operated industrial hydrogenation reactors temperature hot spots have been observed under steady-state conditions. They are attributed to the formation of areas with different fluid residence time due to obstructions in the packed bed. It is shown that in addition to these steady-state effects dynamic instabilities may arise which lead to the temporary formation of excess temperatures well above the steady-state limit if a sudden local reduction of the flow rate occurs. An example of such a runaway in an industrial hydrogenation reactor is presented together with model calculations which reveal details of the onset and course of the reaction runaway. 

HC2 Temporary human capacities are inadequate (e.g. occasional use of alcohol, drug, medicine, or non-chronic emotional instability). 

One might say that with the GUT scenario, our existence is assured by the ultimate instability of matter that makes us, despite a very long lifetime. The baryon dominated universe is only a temporary existence in this picture. 

Due to the thermal instability of PAN, reaction R7 is highly reversible. Thus, PAN is a temporary sink for NO2 in cycle of photochemical reactions. NOjr eventually undergoes further oxidation to nitric acid, which is one of direct causes of acid rain. Some portions of VOCs arc transformed in the atmosphere into aerosols, which are contributors to the decrease in visibility. For the effective control of photochemical smog, reduction of both precursors (VOCs and NOx) should be considered at the same time. 

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