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General Viewpoints

Polansky and Rouvray (1976) started their series of pioneering papers, entitled Graph-Theoretical Treatment of Aromatic Hydrocarbons , at a time when no coronoid hydrocarbon was known chemically. This fact did not prevent the authors to indude corona-condensed systems (coronoids) in their first paper in the series (Polansky and Rouvray [Pg.1]

A third aspect has been drawn to attention (Cyvin SJ, Cyvin and Brunvoll 1989b) Apart from the mathematical and chemical interest. we vdsh to point out the aesthetic motivation. It was perhaps Hosoya (1986a) who first mentioned the aesthetic aspect in the context of mathematical chemistry Thus, all the discussions in this paper have been performed from purely mathematical and, if possible, aesthetic points of view.  [Pg.3]

Multiple coronoids (systems with more than one hole each) of symmetry have been called laceflowers (Cyvin SJ, Brunvoll and Cyvin 1989a Cyvin BN, Brunvoll, Chen and Cyvin 1993). The two cited references contain depictions of these pretty systems up to 54 hexagons they are reproduced in Fig. 2. Also the aesthetic qualities of fractal benzenoids (Klein, Cravey and Hite 1991) can hardly be denied. A representative is shown in Fig. 3. The particular set to which it belongs, starts with the two benzenoids CgHg (benzene) and 2 12 Then [Pg.3]

1993) in coro ene. A = 0 and 1 correspond to benzene and coronene, respectively. The chemical formulas, C H, for members of this particular set obey the recurrence relations (Klein, Cravey and Hite 1991) [Pg.3]


One of the major uses for mathematical models is in the simulation of process operations. This application is readily appreciated by chemical engineers because of the similarity of the model to a pilot plant. In spite of its importance, this subject has not received much attention in the literature. There are probably two main reasons for this. First, process models tend to be quite specific for a particular application and there is little to be said about the subject from a general viewpoint. Second, detailed accounts of specific examples would include information which most firms regard as being of competitive value. [Pg.349]

From the general viewpoint, the ability of a relationship such as Eq. (4.275) to describe the higher harmonics of magnetization is questionable. However, at least for semiquantitative results, one can obtain a useful approximation for y 7 1. For that purpose, let us rewrite Eq. (4.275) as... [Pg.525]

From a general viewpoint, the NiBi3 compound layer growth (except at the very beginning of the Ni-Bi interaction) is due to two partial chemical reactions. Firstly, the Bi atoms may diffuse across the layer bulk from interface 2 to interface 1 (Fig. 1.17) and then react with the surface Ni atoms to form NiBi3 at the Ni-NiBi3 interface ... [Pg.47]

The nutritive characteristics of rice and its relative low cost make of this cereal a staple food in many countries, meeting almost completely (up to 80 percent) the food needs of half of the world population, and contributing over 50 percent of protein to the daily food intake [2]. From a general viewpoint, the major rice-producing countries are also large rice consumers and exporters. In fact, China and India, because of their hot and humid climates, favorable to the cultivation of rice, cover more than 50 percent of the world rice production and account for about 25 percent of the worldwide export of rice [3, 4]. [Pg.384]

The work of Brpnsted and Pedersen (23) on the catalytic decomposition of nitramide and the kinetic studies of Lowry and Faulkner (24) on the mutarotation of tetramethylglucose led to the formulation of a more general viewpoint on acids and bases which logically showed that the hydrogen ion and hydroxyl ion were not the unique carriers of acid and basic properties. An acid was defined as any substance capable of donating a proton, and a base any substance capable of accepting a proton. In accordance with this definition (Lowry, 25 Brpnsted, 26), the following substances are typical acids and bases ... [Pg.243]

From a general viewpoint, the credibility and comparability of environmental analytical data can be assessed through two major parameters, i.e., trueness and precision, which combine into accuracy and express the closeness between an experimental measurement with its uncertainty and the true (or supposedly so) value of a given quantity (40). Such concepts were developed long ago, but are still being refined to accommodate the progress made so far in this sector. Definitions of these and other quantities relevant to this field, for which consensus has been achieved by the scientific community, are listed in Table 1.3. [Pg.18]

The presence of surfactant adsorption monolayers decreases the mobility of the droplet (bubble) surfaces. This is due to the Marangoni effect (see Equation 5.282). From a general viewpoint, we may expect that the interfacial mobility will decrease with the increase of surfactant concentration until eventually the interfaces become immobile at high surfactant concentrations (see Section 5.5.2, above) therefore, a pronounced effect of surfactant concentration on the velocity of film drainage should be expected. This effect really exists (see Equation 5.286, below), but in the case of emulsions it is present only when the surfactant is predominantly soluble in the continuous phase. [Pg.238]

Any face of determined co can be obtained by this method and thus the variation of dl parameters can be investigated from a general viewpoint but a disturbed layer is made at the surface which has to be removed by polishing (see Section IV.3). [Pg.32]

The curvature about the minima is an expression of molecular flexibility, which can be ascertained, in principle at least, from knowledge of the molecular vibrations. From a more general viewpoint, the reaction profile must be regarded as a more or less complicated curve on a multi-dimensional energy hyper-surface. [Pg.174]

Reaction on the surface of a solid on the one side and in the lattice of a crystalline solid on the other side may be regarded as two extreme cases of heterogeneous catalysis, the majority of porous commercial catalysts lying in between. A more detailed understanding of the kinetics of reactions in zeolites could be important, therefore, from a very general viewpoint. [Pg.320]

Such a picture would fall in with the general viewpoint taken in this paper. However, while gold (111) showed a similar adsorption behavior, the reaction rate was proportional to the square of the hydrogen pressure and directly to the oxygen pressure. [Pg.191]

From a general viewpoint, it is suitable to take into consideration the third strategy. It is clear that in such a case it is necessary to use a method that can self-select the parameters a of the model v(a,A ) so as to satisfy at best the boundary conditions. [Pg.242]

Also from a general viewpoint, it is opportune that the function v(a, x) that approximates y and contains P adaptive parameters a has the following features. [Pg.242]

In a brief and very well written article, Alexander Manafu (2013) discusses, from a general viewpoint, the proposal advanced in the original work on ontological pluralism (Lombardi and Labarca 2005). The author does not call into question... [Pg.27]

When one starts to replace the medium consisting exclusively of water by media which from a general viewpoint are less suitable solvents, it may be expected that dicomplex coacervation nonetheless occurs with the salts which stand to the right of the vertical line in the series of symbols given above. This is indeed the case in alcohol-water or acetone-water media One may compare Fig. 42, which relates to 0.087% sols and in which the attached numbers relate to the constant acetone concentration for each curve (namely cc. acetone to 25 cc final volume). [Pg.396]

From a general viewpoint, the current intelligent solutions can be subdivided in two categories with concern to food and beverage applications. [Pg.118]

In both cases the application of the general viewpoints outlined above will afford a fairly deep insight into the mechanism of the formation of these molecular associations and throw light on the analogous relationships in high polymeric substances. [Pg.106]

We briefly considered in Sects. 6.2 and 6.3 how to treat EUE within the UHF approximation which admits to different orbitals for different spin (DODS). For singlet states the UHF scheme is usually called the spin-polarized HF method (then Pa Pfi unhke RHF where = pp). Here we look at the problem from the more general viewpoint which allow us to introduce relevant spin-polarization indices for any singlet many-electron states [62]. [Pg.169]

To describe the phenomenon of selective initiation and inhibition of chain chemical reactions in [1] and later in [2-13], die concept of step value in a complex chemical reaction was introduced in a more general viewpoint. The value of an individual step is defined as the relation of the response of a chosen characteristic dynamic parameter of a reaction system, at some time t, to small perturbation of the y-th step rate at zero time, to. Here, the step rate is varied by changing the initial conditions (the concentrations of initial substances, the reaction rate constants, etc ). In such cases the following expression is true for the value of the Gj step... [Pg.31]

The concept on multicentered reaction system of chain conversion [9] (Section 5.1) enables to consider the conditions of both the selective inhibition and selective initiation of chain reactions from the more general viewpoint. [Pg.98]

His general viewpoint on punishment is that the public must know that their wrongs are being judged severely. It s like this dog here if I tell him to jump down, he knows what will happen to him if he doesn t listen. And the same with my little boy people do things if there s proper authority behind what they re told. [Pg.146]

It appears useful to outline some general viewpoints concerning the requirements of future spaceborne cryotronic applications, particularly as they apply to infrared detecting systems. [Pg.107]


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