Area graphs working with

Overall the present article seeks to meld chemical graph-theoretic (chemicalbonding) ideas with conventional quantum-chemical approaches, all within the framework of traditional VB theory here extended to encompass more recent results and models. Thence use is made of some quantum-chemical nomenclature, which, however, is standard fare in any of a number of quantum chemistry texts, though they seldom seriously discuss VB models for Jt-network systems. Some effort is made to incorporate solid-state theoretic results on one of the models which has arisen with different applications in mind. As such, the present article offers a novel global perspective which (as is so often the case) emphasizes the author s own work in the area. 

Work and heat, on the other hand, are not state functions. Since they depend on path, they cannot be identified with points on a graph, but rather are represented by areas, as shown in Fig. 1.3. The differentials of heat and work are not referred to as changes, but are regarded as infinitesimal quantities of heat and work. When integrated, these differentials give not a finite change but a finite quantity. Thus... 

Although the work reported in this paper has been concerned with combinations of two degrading additives, systems involving three or more additives are being investigated. Even faster rates than were obtained with dual system can be achieved. With three additives and using a typical ternary composition graph, contour lines can be plotted and the area of maximum effectiveness determined quickly. Princeton Polymer... 

Note that we used Equation 12.13 to replace Pg t with the internal pressure P in this reversible process. This is a compact way of saying that the work, w, for a reversible expansion process is (with a minus sign) the area under the graph of P plotted against V from Vi to V2. 

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