Rotators asymmetric

Fig. 15. Mechanically agitated columns (a) Scheibel column (b) rotating-disk contactor (RDC) (c) asymmetric rotating-disk (ARD) contactor (d) Oldshue-Rushton multiple-mixer column (e) Kuhni column and (f) reciprocating-plate column.

Extraction can be performed in stirred tanks if the process proceeds fast and separation of phases is ea.sy, but column extractors are most commonly used. The column can be filled with a particulate material. The liquids flow countercurrently whereby the flow can be uniform or pulsed. Reciprocated and rotary agitators are often used to enhance mass transfer. An example of the latter type is shown in Fig. 7.2-13 (asymmetric rotating disk (ARD) extractor). 

The classical rotational energy of rigid body is given in the general case by Eq. (13). This expression is thus applicable to (iv), the asymmetric rotator. The other types of rotator represent special cases. 

Asymmetric RO membranes, 21 633 Asymmetric rotating disk (ARD) contactor, 10 778... 

Fig. 26. Mechanically agitated industrial contactors, (a) mixer-settler (b) rotating-disk column (c) mixco column (d) asymmetric rotating-disk column (e) pulsed packed column (f) Podbielniak centrifugal extractor. (Reprinted from Doraiswamy, L. K and Sharma, M. M., Heterogeneous Reactions Analysis, Examples and Reactor Design, Vols. I and 2, 1984, John Wiley and Sons.)...

From the above it is apparent that the time profile of the emission anisotropy is very complex for a general, asymmetric rotator. Thus it is unlikely that, even with the superior data obtained with pulsed lasers for sample excitation, meaningful analy-... 

Asymmetric rotating-disk Lurgi tower Pulsed packed Rotating-disk contactor Kuhni... 

Other variations of stirred columns which are available include the asymmetric rotating disc (ARD) contactor, the Kuhni column, and two types of Scheibel columns. The rotor of the ARD is located off center, which permits more elaborate baffling for the necessary transport of flows with less backmixing. 

If the HOMO is asymmetric, rotation has to be conrotatory in order to achieve in-phase overlap. In other words, comotatory ring closure is symmetry-allowed, whereas disrotatory ring closure is symmetry-forbidden. 

Fig. 6.9. Examples of four classes (d" t< (rotators). Hie numbers I. , lyy, Izz represent the eigenvalues of the tensor of inertia computed inaBFCS. There are fourpossibilities (a)alinearrotator(/v.v = lyy =0,/— 0) e.g., a diatomic or CD2 molecule (b) a spherical rotator (I y.y = lyy = /—) e.g., a sphere, a eube. a regular tetrahedron, or a methane molecule (c) a symmetric rotator (/y.v = lyy /—) e.g., a cylinder, a rectangular parallelepiped with square base, ammonia or benzene molecule (d) an asymmetric rotator (/t.t /w 7 f ) e.g., a general reetangular parallelepiped, a hammer, or water molecule.

For the accurate calculation of it is necessary to know the values of the rotation barrier The latter were calculated by us using MOPAC 6 and for the rotation around x and y axes they are 1.8 and 7.5 kcal, respectively. These values correlate well with the energy of NO rotation in the nitromethane molecule [91]. The correction coefficient cp was also determined using the Pitzer tables [92]. Although the latter are designed for symmetric rotators as Pitzer has shown, they can be successfully applied for the approximate estimation of the thermodynamical functions of asymmetric rotators. 

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