Proper perspective

To gain a proper perspective of the role of computed physical properties, the relationship between estimated and computed properties needs to be understood. A thorough reading of Horvath (25) permits formulation of the following definitions of estimating or computing properties. 

For the air quality manager to place model estimates in the proper perspective to aid in making decisions, it is becoming increasingly important to place error bounds about model estimates. In order to do this effectively, a history of model performance under circumstances similar to those of common model use must be established for the various models. It is anticipated that performance standards will eventually be set for models. 

It is important that health factors are kept in proper perspective. What hazards there may be in the case of oil products are avoided or minimized by simple precautions. For work involving lubricants (including cutting fluids and process oils) the following general precautions are recommended ... 

Because much experimental work has been stimulated by the quasi-chemical theory, it is important to gain proper perspective by first describing the features of this theory.12 The term, quasichemical will be used to include the Bragg-Williams approximation as the zeroth-order theory, the Bethe or Guggenheim pair-distribution approximations as the first-order theory, and the subsequent elaborations by Yang,69 Li,28 or McGlashan31 as theories of higher order. 

At the same time, an educational effort should accompany the use of log P/log D by putting the data in proper perspective for the user and undertaking an analysis of failures to gain potential new insight on when the answer is the answer. This is, of course, a paradigm to ensure quality and successful application of data, not limited to log P/log D. 

A second point on which the authors in this anthology agree is that reductionism, as successful as it has been on a host of counts, is seriously inadequate. It must be supplemented with more holistic science. To understand nature in all its vicissitudes, methods from the most reductionist to the least reductionist must be used. Hence, anti-reductionists are forced, like it or not, to advocate pluralism. For example, Robert Williams concludes that We must not despise reductionism. However, it has to be put in a proper perspective . Too often reductionism and anti-reductionism are presented as if they are in diametric opposition when all that separates them is degree of emphasis. As Alfred Tauber observes, reductionism and holism cannot be defined in isolation from each other. An unsteady balance exists between the two. Holism and reductionism are inexorably coupled and cannot be defined independent of each other . As a result, like so many other contributors to this volume, he embraces a pluralistic approach . 

To put the problem in proper perspective, let us consider an instructive example an individual magnetic dipole of moment p subject to a magnetic field H and embedded in a thermal bath. The dipole can switch between the up and down... 

Because the techniques used to study ionic reactions in the gas phase are familiar primarily to chemists in the field, an initial discussion of the experimental methods is necessary in order to gain a proper perspective of this subject. 

Successful construction and use of mathematical models for individual processes soon leads to more ambitious projects. It has already been mentioned, for example, that in petroleum refining most processes cannot be regarded as separate entities because they consume products of other processes and supply raw materials for still other operations. If one tries, however, to construct a mathematical model which will directly represent the operations of an entire refinery, the task can become overwhelming. The size of the model, when looked at in its entirety, is simply too large for a proper perspective. 

But to retain the proper perspective here, let s remember that chlorination is probably the most important public health measure in the history of the world. Chlorine was first used to disinfect water at Maidstone, England, in 1897, during an outbreak of typhoid fever. People had known about the pale green gas since 1774, when the German scientist Scheele generated it by treating salt (sodium chloride) with sulfuric acid and man-... 

This is a time of transition in the organo-fluorine industry and to provide a proper perspective this article has looked backwards as much as forwards. A similar article in 20 years time is likely to present a very different picture. 

The period dining which isotopic tracer techniques have developed has also seen remarkable developments in many other techniques — all forms of spectroscopy, chromatography, automated analyses, etc., and it is necessary to get isotopic techniques in their proper perspective as just another useful tool. The technique has its own unique advantages and limitations. 

A short discussion of thermodynamics is necessary to place the topic of equilibrium into proper perspective. From the viewpoint of thermodynamics a system is in equilibrium when the free energy G is equal to zero. Free energy is the energy available to do work. The free energy of a system depends upon the enthalpy (heat content), H and the entropy(disorder or randomness of the molecules), S. 

Unless one is routinely working with humidity measurements, there is a tendency to overlook the fact that humidity is water gas. behaving in accordance with Ihe ideal gas laws. One of the easiest ways to pul humidity in its proper perspective is through application of Dalton s law of partial pressures Io the most commonly encountered gas-cur,... 

Planar molecules such as benzene, ethene, and methanal are best drawn in the plane of the paper with bond angles of about 120°. When it is desired to draw them as viewed on edge (out of plane) care must be taken to provide proper perspective. The forward bonds can be drawn with slightly heavier lines a tapered bond indicates direction, the wide end pointing toward the viewer and the narrow end away from the viewer (Figure 5-11). Barred lines are used here to indicate a rear or receding bond (many writers use dashed lines, but these may be confused with other uses of dashed lines, as for partial bonds). 

One of the objectives of this chapter has been to articulate the historical development of MCT in a coherent fashion to enable the nonexperts to gather the proper perspective. There are of course more advanced and specialized reviews which the reader can turn to for more details [3, 16]. 

The recognition of electronic delocalization had to wait until the 1930s. The notion has gained a proper perspective with the development of quantum theory and with the recognition that electrons are also waves which are intrinsically delocalized. Heisenberg s theory of resonance,54 which was applied by Heitler and London to the H2 molecule,55 demon-... 

Suppose we deal with a process in which iron, Fe, has to be used as a reactant, for example, in a reduction reaction. The standard chemical exergy of Fe is 376.4 kj/mol. If we wish to carry out a thermodynamic or exergy analysis of this process, this value is not appropriate. After all, to put the exergy cost of the product, for which Fe was needed as a reactant, in proper perspective, we need to consider all the exergetic costs incurred in order to produce this product all the way from the original natural resources— iron ore and fossil fuel in this example. The production of iron from, for example, the iron ore hematite and coal has a thermodynamic efficiency of about 30% [1], and therefore it is not 376.4 kj/mol Fe that we need to consider... 

In proper perspective, i.e., in relation to a 3-billion-year-long developmental period, the distance on the time scale between the eruption of trilobites versus hominids is remarkably short. It is much too short to build a human from an arthropod by gene duplication and mutation ... 

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