CIP

Consideration of stereochem-iitry. The parity or handedness - R/S or chjirans - of a stcreoccnter can be obtained by considering the sequence of the Morgan numbers of die atoms, similarly to CIP. Then the number of pairwise interclianges is counted until the numbers arc in ascending order (see Section 2,8,5). 

Early implementations of the CIP rules for computer detection and specification of chirality were described for the LHASA [105], CHIRON [106], and CACTVS [107] software packages. Recently, several commercial molecular editors and visualizers (e.g., CambridgeSoft s ChemOffice, ACD s I-Lab, Accelrys WebLab, and MDL s AutoNom) have also implemented the CIP rules. 

Other methods have been proposed for detecting chiral carbon atoms which do not rely on the CIP system, and which have been more convenient for some specific applications [108]. 

First, both the skeleton and the ligands at a stereocenter have to be numbered independently of each other. The sites of the skeleton can be numbered arbitrarily but then this numbering has to remain fixed all the time in any further operations. The atoms directly bonded to the stereocenter have to be numbered according to rules such as the CIP rules or the Morgan Algorithm (Figure 2-79). 

The Cahn-Ingold-Prelog (CIP) rules stand as the official way to specify chirahty of molecular structures [35, 36] (see also Section 2.8), but can we measure the chirality of a chiral molecule. Can one say that one structure is more chiral than another. These questions are associated in a chemist s mind with some of the experimentally observed properties of chiral compounds. For example, the racemic mixture of one pail of specific enantiomers may be more clearly separated in a given chiral chromatographic system than the racemic mixture of another compound. Or, the difference in pharmacological properties for a particular pair of enantiomers may be greater than for another pair. Or, one chiral compound may rotate the plane of polarized light more than another. Several theoretical quantitative measures of chirality have been developed and have been reviewed elsewhere [37-40]. 

The Exclusion Prin cip le is t ii an tn ni mechanical in nature, and outside the realm ofeveryday, classical" experience. Think ofii as iheinherent tendency of electron s to slay away from oneanoiher, to be m n tnally excluded. Excbi sion is due to lb c an lisymmdry of the wave function and nol to electrostatic coulomb repulsion between two electrons. Exclusion exists even m the absence of electrostatic repulsions. 

More complex shapes can be made by cold isostatic pressing (CIP). CIP uses deformable mbber molds of the required shape to contain the powder. The appHcation of isostatic pressure to the mold suspended in a pressure transfer media, such as oil, compacts the powder. CIP is not as easily automated as uniaxial pressing, but has found wide appHcation in the preparation of more complex shapes such as spark plug insulators (26). 

Pump Suction. The net positive suction head required (NPSHR) affects the resistance on the suction side of the pump. If it drops to or near the vapor pressure of the fluid being handled, cavitation and loss of performance occurs (13). The NPSHR is affected by temperature and barometric pressure and is of most concern on evaporator CIP units where high cleaning temperatures might be used. A centrifugal booster pump may be installed on a homogenizer or on the intake of a timing pump to prevent low suction pressures. 

A CIP system includes pipelines, interconnected with valves to direct fluid to appropriate locations, and the control circuit, which consists of interlines to control the valves that direct the cleaning solutions and water through the lines, and air lines which control and move the valves. A programmer controls the timing and the air flow to the valves on a set schedule. The 3A Standards for CIP components, equipment, and installation have been developed. A simple CIP system circuit is shown in Figure 11. 

Fig. 11. Modem fermenting tank with conical bottom CIP (cleaning-in-place) = automatic cleaning system.

With this equation the life of the bearing can be determined for different load conditions and is predetermined for the type of drive and service requirements. To select a proper bearing, therefore, the type of application and the loading ratio (CIP) should be carefully selected to ensure the required minimum life. Bearing manufacturers product catalogues provide the working life of bearings for different load factors and may be referred to for data on C, C and other parameters. 

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