Stabilizing Factors

Ellison has published an extremely important factor for steam drum design called the Drum-Level-Stability Factor. As manufacturers have learned how to increase boiler design ratings, the criteria for steam drum design have lagged. The three historical steam drum design criteria have been ... 

This fourth criterion can be met at a low steam drum cost. Only one percent of the cost of the boiler spent on the steam drum can provide it. The fourth criterion is met by requiring that the Drum-Level-Stability Factor (D.L.S.F.) be equal to 1.0 minimum. When this exists the steam drum level will be stable for wide and sudden operational changes. 

Ellison, G. L., Steam Drum Level Stability Factor, Hydrocarbon Processing, May 1971. 

A comparative study on ylide stability as a function of the heteroatom type was carried out by Doering et al. [3,4]. They concluded that the phosphorus and sulfur ylides are the most stable ones. The participation of three-dimensional orbitals in the covalency determines the resonance stabilization of the phosphorus and sulfur ylides [5-8]. The nitrogen ylides are less stable from this point of view. The only stabilization factor involves electrostatic interactions between the two charges localized on adjacent nitrogen and carbon atoms [9]. 

So we have learned that resonance (which delocahzes a negative charge) is a stabilizing factor. The question now is how to roughly determine how stabihzing this factor is. Consider, for example, the following case ... 

The kinetics of formation of phosphonates by reaction of o-dinitrobenzene with phosphites have been examined. The energy of activation for the reaction increases as the nucleophilicity of the phosphite decreases, e.g. ethyl diphenylphosphinite 14kcalmol"S diethyl phenylphosphonite 16 kcalmol S and triethyl phosphite 21kcalmol . An intermediate of the type (61), formed by nucleophilic attack of the phosphite, was proposed. In (61) there is a particularly favourable electrostatic interaction. That p-dinitrobenzene is unreactive, is thought to stem from the fact that this compound cannot form an intermediate with such a stabilizing factor. 

Concerning the competition between redox process and anodic decomposition one can define a stability factor s by... 

A violent decomposition took place when the final compound was decanted. The technical analysis showed that the chlorosulphonic derivative obtained decomposes at a temperature starting at 24-27 C. Oomparing the thermal behaviours of the four compounds just described could be interesting in terms of finding out more about stability factors of a molecule and is a good test to check the CHETAH method (see para 2.3). 

Von Willebrand factor (VWF) is a large multimeric glycoprotein with two main functions in hemostasis to aid the platelet adhesion to injured blood vessel walls and to carry and stabilize factor VIII in plasma. Table 64—4 represents three main vWD phenotypes, their frequency, and genetic transmission.17... 

Of special importance is the reduction of the consumption of oil and petroleum products. The fluctuation of prices in these products constitutes one of the stabilizing factors in the world economy and could lead to serious conflicts. Direct savings of oilfuel by way of improving oil-consuming devices and the replacements of this fuel with appropriate alternatives present one of the major problems to be solved in the nearfuture. 

Indeed, when new countries like the U K. France or China became nuclear powers, countries which were already members of the club were strongly opposed, but now it is quite well accepted that possession of nuclear weapons by those countries did not provoke a catastrophe. Some even consider that the existence of nuclear weapons in different camps was a stabilizing factor during the Cold War and prevented a major conflict during the past half-century. Why, then, the possession by India should not stabilize the relation between India and China, and by Pakistan the relation between Pakistan and India, preventing major conflicts in these zones At least the question may be asked. In the same way, the possession by Israel of nuclear weapons, in the opinion of some, has stabilized the situation in the Middle East. In any case, when a country has decided that it is worth while to make the effort and take the risks of developing nuclear weapons, it seems that after some initial outcry, the world accepts it without major retaliation That shows some kind of hypocrisy in the initial claim of a fundamental evil connected with the proliferation of nuclear weapons. The real issue is probably to avoid the acquisition of nuclear weapons by unstable, not very democratic countries. May be Pakistan is in that category clearly the West would not like Libya or Iran and Iraq to possess such weapons. A real, major issue is full nuclear disarmament, but this is another story. 

Fibrin-stabilizing factor is a protein involved with blood coagulation. 

Therefore, it has been suggested that electrostatic repulsion by ionized Glu222 is a major stabilization factor favoring the neutral protonated form of the... 

XIII Fibrin-stabilizing factor Both Activated form cross-links fibrin, forming a hard clot... 

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