The Most-Specific-Generalization Method

In this chapter we have detailed the processes that give rise to distortion of spectra. Although specifics have been limited to optical spectra, a number of the principles are easily generalized to other fields, including those for which data are acquired in more than one dimension. In the next chapter we introduce traditional methods of undoing the distortion, along with some of the concepts needed to develop the most successful modern methods described in Chapter 4. 

For materials generally, change in expansion (or density) by dilatometry was traditionally the most often used method for measuring Tg. Thermal properties, for example specific heat, are also widely used, particularly the methods of differential thermal analysis". A method for rubbers using DSC is being developed in ISO TC 45 as ISO 22768, but is not yet published. The inflection point on the heat input - temperature curve is usually obtained automatically by the analyser s software but, if obtained manually, is best found from the derivative of the curve. 

Thiocarbonyl compounds have recently emerged as synthetic tools with specific properties. Although some thioamides and thioketones were prepared as early as the 19th century, general methods are rather recent. Nowadays most, if not all, thiocarbonyl compounds that one can imagine can be prepared, with techniques adapted to the stabilities of the target molecules. 

In general, a TPH method generates a single concentration based upon the total amount of petroleum compounds measured by a specific technique. The most frequently used methods are based on gas chromatography (GC), infrared (IR) or gravimetric analytical techniques. Of these, GC techniques are the preferred choice as they not only detect a broad range of hydrocarbons but also provide... 

As should be evident from the preceding sections, different types of molecular structures create specific demands to achieve optimal coupUng. It is therefore appropriate to describe the specific properties of the respective molecular classes used as interacting partners and to suggest the most suitable immobilization methods for each of them. A more extended general review of the modification and conjugation of different classes of interacting partners may also be found in [25]. 

In most situations it remains necessary to rely on other alternatives. The most rec-ommendable method to prevent the occurrence of dust explosions is inertization. Some details to be observed in its application will be presented in Section 7.4. At this point, some general remarks shall just be made. The highest allowable oxygen concentration is substance specific. Experimental methods for the determination of this limit concentration are well known. In a first approximation it may be assumed, however, that the oxygen limit concentration for organic powders and dusts will not be lower than 8%. For metal dusts this value has to be halved. 

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