Special operating features

In the previous discussion we have described the fundamental components of infrared spectrophotometers. In actual practice many 

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Since this is a book concerned primarily with applications, no further details are given concerning instrumentation. The reader is referred to Alpert et al. (1970), in which are discussed an optical diagram of a double-beam spectrophotometer operating variables (resolution, photometric accuracy) components of infrared spectrophotometers (sources, types of photometers, dispersing elements, detectors, amplifiers, and recorders) special operating features, such as optimization of scan time and available instruments and their specifications. The books by Martin (1966), Conn and Avery (1960), and Potts (1963), and the chapter by Herscher (1966) are also recommended for details on some of these topics. 

SPECIAL OPERATING FEATURES OF MINI-FUEL CELLS... 

Weather data for a number of years should be assembled for each community being studied. Particular attention should be given to such natural disasters as hurricanes, earthquakes, and floods, which often can be predicted from meteorological data. In certain locations these catastrophic events must be assumed to be probable and this increases construction costs. E.xtremely cold weather often hampers process plant operation and requires special construction features to protect equipment from freezing. Predominantly warm weather permits cheaper construction but may also reduce the efllcicncy of the labor force. 

When new plants are constructed or when modifications are needed in existing plants, detailed process designs are required. These designs must include special safety features to protect the system and operating personnel. The following case histories emphasize the importance of these special safety design features. 

Batch crystallizers can be used in a campaign to produce a particular product and in a second campaign to produce another product. Generally, it is not possible to operate continuous processes in this way. Batch crystallizers can handle viscous or toxic systems more easily than can continuous systems, and interruption of batch operations for periodic maintenence is less difficult than dealing with interruptions in continuous processes. The latter factor may be especially important in biological processes that require frequent sterilization of equipment. Batch crystallizers can produce a narrow crystal size distribution, whereas special processing features are required to narrow the distribu-... 

A minor product observed in the photolysis of DBK in aqueous HDTCl (Fig. 5) is the isomeric ketone 4-methylphenylacetophenone (PMAP, 3) 15 18). The question arises as to whether the formation of 3 is due to some special orienting feature of the micelle which operates on the ratio of coupling products 1 and 3. Although 3 has not been detected by the conventional analytical methods for product analyses, (e.g., vpc), some 3 is detectable via chemically induced dynamic nuclear polarization (CIDNP) measurements 28). Thus, it may be that the ratio of formation of 1 to 3 is similar in both micellar and homogeneous solutions, but that the absolute yield of both combination products is so much smaller in homogeneous solution that 3 is not detectable by conventional analyses. 

Considering industrial operational features of the Claus proce.ss, we have suggested that deactivation of Claus catalysts may occur nonuniformly through the catalyst bed. In this paper, results are presented of an investigation of samples of the industrial alumina Claus catalyst after three years of use obtained by irteans of a specially designed device from four different bed heights of a Claus converter. 

Of some interest are also so-called steam-gas generators that produce steam-gas mixtures with high pressures and temperatures. They may have output capacities and other operating parameters that are very similar to those of the traditional steam generators. But they have a number of special design features that make t lore economic, e.g. small dimensions and weight, also insignificant amount of metal required ir construction. 

The thermal energy of the hot reaction gases is used to produce hot steam in a heat exchanger of special design and operational features that prevent the formation of deposits by the hot carbon black present in the gas. 

CPU with speoial hardware features for functional safety, a special operating system and embedded functions for control of failures (for application programming and software integration the integrated redundancy is covered by the development system. The programmer sees only one CPU) ... 

A very special type of cosolvent is a surfactant. Recently, DeSimone and coworkers have developed surfactants that can solubilize polymeric substances in supercritical carbon dioxide (see Johnston, these proceedings). Amongst many applications visualized by this group, the substitution of liquid carbon dioxide for CFCs in dry cleaning operations features prominently. 

It was pointed out in the mechanistic discussion concerning acetal and ketal hydrolysis that general acid catalysis occurs only for acetals and ketal having special structural features. Usually, specific acid catalysis operates. The question of whether general acid catalysis could be observed in intramolecular reactions has been of interest because intramolecular general acid catalysis is postulated to play a part in the mechanism of action of the enzyme lysozyme, which hydrolyzes the acetal linkage present in certain polysacharides. One group of molecules that has been examined as a model system are acetals derived from o-hydroxybenzoic acid (sali-... 

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