Origin of concept

Tracing the origins of concepts is difficult when the inchoate professions that are trying to appropriate them are in a state of flux, and, reflecting this, the intellectual features of chemical engineering up to 1939 have been described in various and inconsistent ways. Olaf Hougen and Franklin J. Van Antwerpen, for example, identify the unit operations... 

Notice that the definition does not use adjectives like better, superior, improved, more cost-effective, higher quality, etc., to qualify as an innovation. In our vocabulary, however, we are not interested in innovation for the sake of novelty or even originality of concept but for the sake of some other positive technoeconomic attributes. 

Carey, S. (2009). The Origin of Concepts. New York Oxford University Press. 

Having separated the dynamical from equilibrium (or, more accurately, quasi-equilibrium) effects, one can readily discover the origin of the activation free energy and define the concept of the potential of mean force by analysis of the expression for the TST rate constant, k in (A3.8.3). The latter can be written as [7]... 

The nonbonding electrons of the nitrogen atom are important in determining spin re-pairing, and thus the conical intersections. This is the physical origin of the topicity concept developed by Salem and co-workers [2,30]. Two different spin... 

The single Slater determinant wavefunction (properly spin and symmetry adapted) is the starting point of the most common mean field potential. It is also the origin of the molecular orbital concept. 

From the concept of isomerism we can trace the origins of the structural theory—the idea that a precise arrangement of atoms uniquely defines a substance Ammonium cyanate and urea are different compounds because they have different structures To some degree the structural theory was an idea whose time had come Three scientists stand out however for independently proposing the elements of the structural theory August Kekule Archibald S Couper and Alexander M Butlerov... 

Since the original proof of concept, and a later demonstration of its practical use in semiconductor manufacturing (40), appHcations and extensions of this concept have proliferated. In the following sections these systems are described in greater detail with emphasis on the resist formulation at a components level (41). 

The origin of the fugacity concept resides in Eq. (4-72), an equation vahd only for pure species i in the ideal gas state. For a real fluid, an analogous equation is written ... 

To conclude, the concept of bond stiffness, based on the energy/distance curves for the various bond types, goes a long way towards explaining the origin of the elastic modulus. But we need to find out how individual atom bonds build up to form whole pieces of material before we can fully explain experimental data for the modulus. The... 

The whole of polymer science is constructed around a battery of concepts which are largely distinct from those familiar in other families of materials, metals in particular. This is the reason why I invited an eminent polymer scientist who was originally a physical metallurgist to write, for a textbook of physical metallurgy edited by me, a chapter under the title A metallurgist s guide to polymers (Windle 1996). The objective was to remove some of the mystery surrounding polymer science in the eyes of other kinds of materials scientists. 

The fluid mechanics origins of shock-compression science are reflected in the early literature, which builds upon fluid mechanics concepts and is more concerned with basic issues of wave propagation than solid state materials properties. Indeed, mechanical wave measurements, upon which much of shock-compression science is built, give no direct information on defects. This fluids bias has led to a situation in which there appears to be no published terse description of shock-compressed solids comparable to Kormer s for the perfect lattice. Davison and Graham described the situation as an elastic fluid approximation. A description of shock-compressed solids in terms of the benign shock paradigm might perhaps be stated as ... 

The origin of the remarkable stereoselectivities displayed by chiral homogeneous catalysts has occasioned much interest and speculation. It has been generally assumed, using a lock-and-key concept, that the major product enantiomer arose from a rigid preferred initial binding of the prochiral olefin with the chiral catalyst. Halpren 48) on the basis of considerable evidence, reached the opposite conclusion the predominant product enantiomer arises from the minor, less stable diastereomer of the olefin-catalyst adduct, which frequently does not accumulate in sufficient concentration to be detected. The predominant adduct is in essence a dead-end complex for it hydrogenates at a much slower rate than does the minor adduct. 

Finally, in any projected landscape due consideration should be given to the future maintenance of the completed scheme. Unlike a normal building development, a landscape progressively develops with time. In order to maintain the original design concept a clear maintenance regime and organization should be established early in the project development process to start as soon as the landscape has been initially established. 

The problem with triads, as well as the other important numerical hypothesis due to Prout, is easy to discern in retrospect. It is simply that atomic weight, which both concepts draw upon, is not the most fundamental quantity that can be used to systematize the elements. The atomic weight of any element depends on the particular geological origin of the sample examined. In addition, the atomic weight of any particular element is an average of several isotopes of the particular element. 

This chapter builds an understanding of atomic structure in four steps. First, we review the experiments that led to our current nuclear model of the atom and see how spectroscopy reveals information about the arrangement of electrons around the nucleus. Then we describe the experiments that led to the replacement of classical mechanics by quantum mechanics, introduce some of its central features, and illustrate them by considering a very simple system. Next, we apply those ideas to the simplest atom of all, the hydrogen atom. Finally, we extend these concepts to the atoms of all the elements of the periodic table and see the origin of the periodicity of the elements. 

Garrels, R. M. and Mackenzie, F. T. (1967). Origin of the chemical compositions of some springs and lakes. In "Equilibrium Concepts in Natural Water Systems" (W. Stumm, ed.). Advances in Chemistry Series 67, pp. 222-274. American Chemical Society, Washington. 

---