Effective particle weight

Dilute-phase momentum balance all effective particle weight in unit dilute-phase volume is balanced by the fluid drag ... 

Dense-phase momentum balance effective particle weight in unit dense-phase volume is partially supported by the dense-phase fluid flow, and the rest is supported by the bypassing dilute phase fluid flow,... 

Under equilibrium conditions the net primary force /o comprises drag, eqn (4.25), and the effective particle weight (the net effect of gravity and buoyancy), eqn (4.21) ... 

In this section we will discuss two studies that were performed to investigate factors which may effect particle size control (1) the type of support material and (2) the weight loading. 

Unless 7 1, all terms in Eq. (11-33) must be retained. Since Eq. (11-30) has no formal justification, the individual terms cannot definitely be ascribed to added mass or history effects. Even so, the relative magnitudes of the terms are of interest. Figure 11.7 shows the three terms for specific values of 7 and Rejs, expressed as fractions of the immersed particle weight. Added mass dominates initially history passes through a maximum and decays slowly steady drag increases monotonically to become the sole component at the terminal velocity. Both A and Ah depart from unity early in the motion. For smaller Rexs, history may be the dominant drag component for a brief period (02). 

Several configurations for the sensor are possible. An especially viable alternative would seem to be the competitive displacement of fluorescent label. Since this is an equilibrium, fouling or contamination of the surface should not alter the absolute result. Krull et al (75) have reported the reproducible immobilisation of a stable phospholipid membrane containing fluorophore in this context. Concurrent fluorescence polarisation measurements can offer the possibility of multidimensional analysis (76) and are in any case experiencing a rejuvenation of interest as a highly selective technique, when the effective molecular weight of the antibody is increased relative to the antigen, by immobilisation on a latex or metal particle (77)... 

Third, for particles smaller than about 100 pm, cohesive forces (believed to be due to van der Waals interactions for intimate contacts, and to surface tension of adsorbed water layers for lubricated contacts) between particles becomes comparable to particle weights, and small particles can stick to one another in relatively rigid aggregates. Unless such aggregates are destroyed, the system will behave as if it had an effective particle size much larger than the primary particle size. 

Since temperature and concentration must be the same for the two reactions if we are to compare them under the same conditions, any difference in collision frequency would have to arise from differences in particle weight or size. A bro mine atom is heavier than a chlorine atom, and it is also larger as we have seen, the effects of these two properties tend to cancel out. In actuality, the collision frequencies differ by only a few per cent. It is generally true that for the same temperature and concentration, two closely related reactions differ but little in collision frequency. A difference in collision frequency therefore cannot be the cause of a large difference in reactivity. 

In concentrated urea solution and at pH values below 2.8 the particle weight determined osmotically falls to 53,000, three times the minimal value from the histidine content. Since the effect of acids is fully reversible—the tropomyosin crystallizes as well afterwards as before— this is evidently the weight of the true monomer. The particle weight at 7 = 0.27 and pH 6.5 thus corresponds to an average degree of polymerization of about 2. 

Macromolecules generally have a molecular-weight distribution. When they associate, a particle-size distribution is produced, which will be different from the molecular-weight distribution and will vary with the nature of the effective unit. The relationships between the molecular-weight distributions and the particle-weight distributions can be derived by statistical methods. Only the results are given here. 

Fig. 17.23 Effect of weight average elastomer particle sizes on the notched impact strength of a-PA/elastomer blend (80/20) nanocomposites containing (a) EOR and (b) EOR-g-MA. Data for a-PA/ EOR (—g-MA) blend without organoclay are from Huang et al. (2006b)...

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