What can go wrong

Identify the scenario. What can go wrong to result in the loss of containment of the material ... 

Risks were expressed as triplets . The first element of the triplet was found using accident records and a PHA. The databases used were MHIDAS (1992) (>5(XK1 accidents) and ACCIDATA (>1,500 mostly Brazil). The PHA was performed by personnel from REDUC (facility operator) and PRINCIPIA (the PSA vendor). About 170 basic initiating events (raptures of pipes, flanges, valves, spheres, pumps and human actions) were grouped into 12 initiators by equivalent diameter, pressure, flow type and rapture l(x ation. 

The last three decades have seen the development of a new science to help us better understand the risk of events about which there is often very little information. The reason there is interest in such a science is that there are a great many societal benefits from activities that involve risk risk that if properly managed through better understanding can greatly benefit the quality of all life on the planet earth, both plant and animal. That science is quantitative risk assessment, also known by such names as probabilistic risk assessment and probabilistic salety assessment, the latter being the preferred name for this text. Probabilistic safety assessment divides the risk question into three questions "What can go wrong " "How likely is it " and "What are the consequences "... 

Examples illustrating what can go wrong if the constraint gradients are dependent at x can be found in Luenberger (1984). It is important to remember that all local maxima and minima of an NLP satisfy the first-order necessary conditions if the constraint gradients at each such optimum are independent. Also, because these conditions are necessary but not, in general, sufficient, a solution of Equations (8.17)-(8.18) need not be a minimum or a maximum at all. It can be a saddle or inflection point. This is exactly what happens in the unconstrained case, where there are no constraint functions hj = 0. Then conditions (8.17)-(8.18) become... 

This book presents the basic techniques in the organic chemistry laboratory with the emphasis of doing the work correctly the first time. To this end, examples of what can go wrong are presented with admonishments, often bordering on the outrageous, to forestall the most common of errors. This is done in the belief that it is much more difficult to get into impossible experimental troubles once the student has been warned of the merely improbable ones. Complicated operations, such as distillation and extraction, are dealt with in a straightforward fashion, both in the explanations and in the sequential procedures. 

As will be shown for the CD model, early mixing models used stochastic jump processes to describe turbulent scalar mixing. However, since the mixing model is supposed to mimic molecular diffusion, which is continuous in space and time, jumping in composition space is inherently unphysical. The flame-sheet example (Norris and Pope 1991 Norris and Pope 1995) provides the best illustration of what can go wrong with non-local mixing models. For this example, a one-step reaction is described in terms of a reaction-progress variable Y and the mixture fraction p, and the reaction rate is localized near the stoichiometric point. In Fig. 6.3, the reaction zone is the box below the flame-sheet lines in the upper left-hand corner. In physical space, the points with p = 0 are initially assumed to be separated from the points with p = 1 by a thin flame sheet centered at... 

Since exposure of a spontaneously combustible material to air has obvious consequences, loss of containment or other means of air exposure is usually the most important issue regarding what can go wrong. It should be noted that pyrophoric materials often exhibit one or more other reactivity hazards as well, such as water reactivity. Possible causes of uncontrolled reactions associated with pyrophoric and other spontaneously combustible materials include abnormal events such as the following ... 

Inadvertent contact of a water-reactive material with water is obviously the most important issue regarding what can go wrong. Due to the prevalence of water in living tissues, water-reactive materials are often toxic or corrosive as well, so loss of containment is often an additional concern. The following are some of the possible causes of uncontrolled reactions associated with water-reactive materials ... 

Five general categories of what can go wrong with self-reactive materials are ... 

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