Containment structural concepts

Containment Structure Concepts. In some types of safety facilities, it is either necessary or desirable to completely contain the effects of internal explosions. This requirement can arise because personnel, critical equipment, or critical operations must be located very near the facility, so one wishes to entirely eliminate blast emitted from the safety structure. A more stringent requirement requiring complete containment occurs in facilities for demilitarization of chemical munitions. Here, the extremely toxic... 

In another study, Fourcroy is cast as the historian of the chemical revolution, a role he fulfils admirably as he was both spectator and participant in the most important chemical events of the period.230 The importance of the language of chemistry has been stressed by Trevor Levere231 and by Pierre Laszlo.232 It has also been contended that the new chemistry contained the seeds of later structural concepts.233 This may be pushing the potential of Lavoisier s anti-phlogistic chemistry and its revised nomenclature too far, yet without all these main components, the fundamental reorganization of chemistry could not have been achieved. Fresh interest was also stimulated in Lavoisier s collaborators and contemporaries. For example, the... 

What about the claimed synthesis of carbyne reported several times in literature and the uncertain detection of this allotrope in certain meteorites One important distinction is between carbyne and carbynoid structures. Carbyne remains an ideal structure for the representation of the pure sp-hybridized carbon allotrope. An almost infinite chain of carbon must be a solid, insoluble in any solvent under standard conditions, as they are the other well known allotropes graphite and diamond. On the other hand the carbynoid structures represent any carbon solid which contains polyyne chains, even very long chains, or domains, but stabilized in a matrix of other differently hybridized carbon atoms. Therefore, many publications on the synthesis of carbyne must be interpreted and rationalized in terms of the carbynoid structure concept. 

Centropolyindanes constitute a complete family of arylaliphatic polycyclic hydrocarbons containing several indane units. Mutual fusion of the five-membered rings leads to three-dimensional, carbon-rich molecular frameworks bearing a central carbon atom, such as benzo-annelated [3.3.3]propellanes, triquinacenes, and [5.5.5.6]- and [5.5.5.5]fenestranes. In this review, the structural concept of centropolyindanes is contrasted to other fused indane hydrocarbons. Besides the syntheses of the parent centropolyindanes and recently described related indane hydrocarbons, the preparation of a large variety of bridgehead and arene substituted centropolyindanes is presented including strained, heterocyclic, and centrohexacyclic derivatives. In appropriate cases, the particular reactivity and some structural features of these unusual, sterically rigid polycyclic compounds are pointed out. 

This indicates that the molecule rotates, describing a cone the top of which is the sulfur atom. It should seem strange that for dithiols, in which two sulphur atoms are present, the elementary area is smaller, but the reason for it is that the second atom of sulfur plays the part of an anchor and the rotation stops. In this case the molecule is oriented parallel to the surface. Maxted combines structural conceptions with electronic ones, drawing attention to the fact that substances containing atoms with undivided electronic pairs, e.g., a sulfur atom in sulfides, are especially poisonous. 

As a final barrier against fission product release, a containment system is one of the important Engineered Safety Features (ESF) in a current nuclear power plant. It consists of a containment structure and several systems to maintain the integrity of contaminant during accident scenarios. This system is very expensive. Recently, along with the development of advanced nuclear power plant, especially for more innovative reactor designs, the concept of a containment is also getting development. For example, a vented confinement concept... 

The concept of double containment has been adopted for Indian PHWRS. The containment structure consists of a cylindrical prestressed cement concrete (PCC) primary containment with PCC dome and a secondary containment of reinforced cement concrete (RCC) structure completely surrounding the primary containment. 

F igure 9 shows a bench test of the turbine prior to its being mounted to the cryogenic container (of which the turbine is the closer of one end). This setup represents a nonminiaturized unit used in current development work, incorporating, however, airborne structure concepts in all parts. It is noticeable that the expander can be removed or replaced as a compact component by simply removing a few bolts, within a few minutes. 

Fat-containing structures were found to increase in attenuation with increasing photon energy this is opposing to higher density structures as, e.g., iodine contrast. However, a proof-of-concept for the differentiation of Hpid versus fibrous tissue is still lacking. 

I do, however, consider it sensible to introduce the word primary valence chain , because it refers to structures that are not completely identical to what has been called a molecule up to now. 1 always associate the word molecule with the concept of a large number of completely identical structures, whereas the term primary valence chain is specifically supposed to include the fact that the same substance contains structures that are very similar to each other, cannot be separated from each other by chemical methods but differ from one another a little in their size, so that while it is not possible to indicate a precise molecular weight, an average primary valence chain length can be quoted. If this fact is specifically added to your macromolecule, then the two terms are, as far as I can see, identical and it is a question of convenience whether one says primary valence chains or macromolecules of fluctuating size . 

---