Rotation mechanism

Extension of sloping tank classifiers, with settling occurring in large circular pool, which has rotating mechanism to scrape sands inwards (outwards in Bowl Desiltor) to discharge rake or spiral. 

Basically a hydraulic bowl classifier. Vibrating plate replaces rotating mechanism in pool. Hydraulic water passes through perforations in plate and fluidizes sands. 

Hydraulic cone classifier V°W (M-F) Open cylindrical upper section with conical lower section containing slowly rotating mechanism. 0.6 to 1.6 400 im to 100 im (6 mm) 10 to 120 Not critical 2 to 15. 30 to 50 3 to 7.5 Used primarily in closed circuit grinding to reclassify hydrocycloue underflow... 

Distributor The rotating mechanism that distributes the wastewater evenly over the surface of a trickling filter or other process unit. 

Asano and co-workers have reported die kinetic effects of pressure, solvent, and substituent on geometric isomerization about die carbon-nitrogen double bond for pyrazol-3-one azomethines 406 (R = H), 406 (R = NO2) and 407, (Scheme 93). The results demonstrate the versatility of die inversion mechanism. The rotation mechanism has been invalidated. First-wder rate constants and activating volumes for diermal E-Z isomerization for 406 (R = H) and 406 (R = NO2) are given at 25°C in benzene and methanol (89JOC379). 

Nitrobenzenediazoate can be considered as an azo compound comparable to an azobenzene having one electron acceptor and one donor on each side of the azo group the acceptor-donor relationship is more dominant in the (Z) -> (E) diazoate pair than in the diazohydroxide pair. The N=N rotation mechanism of the diazoate pair is therefore the favored process (E = 84 kJ mol-1 Lewis and Hanson, 1967). On the other hand, 4-C1 is not a substituent with a —M effect therefore it does not reduce the double-bond character of the N = N bond and the mechanism involving inversion at the N((3)-atom becomes dominant. The activation energy of the latter process (E = 104 kJ mol-1 Schwarz and Zollinger, 1981) is higher than that of the N = N rotation mechanism for the 4-nitro derivative, but it is reasonable to assume that it is lower than that for N = N rotation in the 4-chloro derivative. Furthermore, one can conclude that N-inversion is more favorable in the diazohydroxide than in the diazoate. ... 

In summary. SRPAC is a powerful tool that yields information about both rotation rates and rotation mechanisms. This method can be extended to molecules other than FC, provided they possess a finite EFG at the Fe center. 

Live oil with dissolved methane does not follow the above correlations as methane relaxes by a spin-rotation mechanism, even when dissolved in liquid hydrocarbons [13]. The Ti relaxation time as a function of rj/T is illustrated in Figure 3.6.2 for different gas/oil ratios expressed in units of m3 m-3 as a parameter. The solid line is the fit for zero gas/oil ratio and is given by Eq. (1). 

The relaxation of gaseous methane, ethane and propane is by the spin-rotation mechanism and each pure component can be correlated with density and temperature [15]. However, the relaxation rate is also a function of the collision cross section of each component and this must be taken into account for mixtures [16]. This is in contrast to the liquid hydrocarbons and their mixtures that relax by dipole-dipole interactions and thus correlate with the viscosity/temperature ratio. 

Cis-trans isomerization occurs either by formation of a half-hydrogenated state (Horiuti-Polanyi mechanism) followed by rotation around the newly formed single bond and abstraction of an appropriate hydrogen onto the surface or by double bond migration (either Horiuti-Polanyi or Jt-allyl) from a cis (trans) position to an adjacent trans (cis) position (deuterium exchange studies favor the rotation mechanism). 

One type of diffusion mechanism is known as the interstitial mechanism because it involves movement of a lattice member from one interstitial position to another. When diffusion involves the motion of a particle from a regular lattice site into a vacancy, the vacancy then is located where the site was vacated by the moving species. Therefore, the vacancy moves in the opposite direction to that of the moving lattice member. This type of diffusion is referred to as the vacancy mechanism. In some instances, it is possible for a lattice member to vacate a lattice site and for that site to be filled simultaneously by another unit. In effect, there is a "rotation" of two lattice members, so this mechanism is referred to as the rotation mechanism of diffusion. 

The first comparison is based on the T values of gaseous, liquid and adsorbed molecules. Unfortunately, no measurements are available for butenes in the gas or liquid phase. Nevertheless a reasonable parallel can be drawn with propylene where the three different phases were investigated (35) at 295 K for the gas (1 atm) Tj of C2 is 0.095 s in the liquid state (2.6. M in CDCI3) 59.9, 58.7 and 65.2 s for Cj, C2 and C3 respectively adsorbed on NaY zeolite 0.81, 1.6 and 0.81 s. The shortest relaxation times characterize the gas phase where the spin-rotation mechanism (NOE factor n = 0) is very effective (30,35). In the liquid, dipole-dipole and spin-rotation mechanisms both play a role and the total relaxation rate is about three orders of magnitude lower than in the gas phase. The adsorbed molecules show therefore an intermediate behaviour between gas and liquid, as it was also suggested by chemical shift data. 

The energy produced in the calorimeter proper as a result of friction in the rotating mechanism and stirring of the calorimetric liquid by the rotation of the bomb may be substantial. Yet provided that this effect is constant, its contribution to the energy of the calorimetric process can be accurately subtracted. If the bomb is rotated during the calibration and the sample runs, and if the rotation is started and ended at the same instants of the respective main periods, then the energy... 

The corrections due to the bomb rotation can also be eliminated by using a dynamic calorimeter, in which the whole calorimeter is rotated and the rotation mechanism is outside the calorimeter proper. An example of such instrument is the aneroid calorimeter developed by Adams, Carson, and Laye [77], shown in figure 7.9. 

Figure 13.9. The rotation mechanism spheres referring to steric hindrance by ligand [5]...

Fig. 5 Possible motions of the type II receptors during interaction with the TGF-fS ligand. Binding of the ligand to the T RII receptor homodimer induces rotation and swinging of the extracellular domains, which are translated through the transmembrane parts into rearrangements of intracellular domains by means of a flexible rotation mechanism, finally causing dissolution of the dimer and spatial separation of the receptor monomers...

Following the historical approach from Tadmor and Klein [1] using screw rotation mechanics, the boundary condition at the top of the solid bed (y = 0) and at the barrel wall (y = 6c) are as follows ... 

The rotation mechanism rotates the gripper 90° to provide re-mixing of the medication within the canister. 

However, quantitative evaluation of the size of this preference depended on knowing the size of the secondary deuterium isotope effect on which C—C bond in 7b cleaves. With the seemingly reasonable assumption of a secondary isotope effect of 1.10 on bond cleavage, the experimental data led to the conclusion that double methylene rotation was favored over single methylene rotation by a factor of 50 in the stereomutation of 7b. Although the error limits on the measurements were large enough to allow the actual ratio to be much smaller, Berson wrote, There is no doubt that the double rotation mechanism predominates by a considerable factor. ... 

Sixteen years later Baldwin and co-workers published the results of even more elegant experiments in which the stereomutation of optically active 7-l- C-l,2,3-was studied. Because a deuterium atom is attached to each of the carbons in this compound, it was unnecessary for Baldwin to assume the size of a secondary deuterium isotope effect on which bond cleaves, in interpreting his kinetic data. The results of his experiments led him to conclude, the double rotation mechanism does not predominate by a substantial factor. ... 

A number of azabicyclic derivatives have also been investigated (7 ICC 1104) as model compounds to study the effect of increasing the nitrogen inversion barrier upon the amide rotational barrier. From the experimental results and simplified MO pictures of the inversion and rotational mechanism, the authors (71CC1104) conclude that changes in the amide rotational barrier do not necessarily correspond to enhancement of the nitrogen inversion barrier. 

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