Suspensions state

In the adequate case (1.0 or 2.0 mL tetralin), the catalyst appeared to be wet differently from dry sand-bath or suspension states. As in the case of decalin dehydrogenation under the superheated liquid-film conditions, the catalyst temperature is higher than the boiling point, exhibiting a temperature gradient, and the substrate liquid is limited in amount to... 

Ansarian, H.R., Derakhshan, M., Rahman, M.M., Saknrai, T., Takafnji, M., Tanigu-chi, I., and Ihara, H., Evalnation of microstructuralfeatnres of a new polymeric organic stationary-phase grafted on silica surface a paradigm of characterization of HPLC-stationary phases by a combination of suspension-state H-1 NMR and solid-state C-13-CP/MAS-NMR, Anal. Chim. Acta, 547,179, 2005. 

In terms of the common features of colloids just listed, nanoparticles with a clean surface have tendency to amalgamate when placed on a TEM sample mesh that is evident in Figures 9.4.16 and 9.4.17. Furthermore, the particles often grow by collision (not by Ostwald ripening because metal ions are hard to dissolve in organic liquids) in the suspension state when the number density of particles in... 

For maximum utilization of the solid phase in a bubble column, it is essential that all particles be suspended in the reactor (Ramachandran and Chaudhari, 1984). This means that the gas velocity should be sufficiently high to enable suspension of all solids in the liquid. In slurry bubble column reactors, two suspension states exist ... 

Agitated vessels (liquid-solid systems) Below the off-bottom particle suspension state, the total solid-liquid interfacial area is not completely or efficiently utilized. Thus, the mass transfer coefficient strongly depends on the rotational speed below the critical rotational speed needed for complete suspension, and weakly depends on rotational speed above the critical value. With respect to solid-liquid reactions, the rate of the reaction increases only slowly for rotational speed above the critical value for two-phase systems where the sohd-liquid mass transfer controls the whole rate. When the reaction is the ratecontrolling step, the overall rate does not increase at all beyond this critical speed, i.e. when all the surface area is available to reaction. The same holds for gas-liquid-solid systems and the corresponding critical rotational speed. 

A deeper insight into the physical nature of the process. By representing experimental data in a dimensionless form, physical states (e.g. turbulent or laminar flow range, suspension state, heat transfer by natural or by forced convection, and so on) can be delimited from each other and the limits quantified. In this manner, the domain of individual physical quantities also becomes apparent. 

As mentioned earlier, suspensions of particulate rods or fibers are almost always non-Brownian. Such fiber suspensions are important precursors to composite materials that use fiber inclusions as mechanical reinforcement agents or as modifiers of thermal, electrical, or dielectrical properties. A common example is that of glass-fiber-reinforced composites, in which the matrix is a thermoplastic or a thermosetting polymer (Darlington et al. 1977). Fiber suspensions are also important in the pulp and paper industry. These materials are often molded, cast, or coated in the liquid suspension state, and the flow properties of the suspension are therefore relevant to the final composite properties. Especially important is the distribution of fiber orientations, which controls transport properties in the composite. There have been many experimental and theoretical studies of the flow properties of fibrous suspensions, which have been reviewed by Ganani and Powell (1985) and by Zimsak et al. (1994). 

Table XIV summarizes the reaction of silyl enol ether (14a) with an acetal (15a) in the presence of various acids. The reaction proceeded smoothly with the aid of acidic solids even under heterogeneous conditions (a suspension state) to afford the corresponding aldol adducts in good yield (Entries 1 - 5,7). Among the strong solid acids examined, aluminum ion-exchanged montmo-rillonite (Al-Mont) showed the highest catalytic activity (Entries 1,2) and good diastereoselectivity for the erythro adduct, especially in 1,2-dimethoxyethane (DME)(Entry 2).

Such a value for the average density is only approximately correct for power calculations (although it is appropriate in most cases), as the solids fraction in the impeller region may differ from 0 depending on N, i.e., on the solids suspension state. 

When different criteria for describing the suspension state are in use, these must also be taken into consideration in the formulation of the suspension characteristics. Depending on which criterion is used in the determination of the critical stirrer speed Wx , which can be represented by x for the 1-s criterion, for the particle layer height criterion h = 0.9 or by a required distribution quality the process numbers are correspondingly designated e.g. Re or Fr. ... 

Kneule [286, 0.11] has pointed out, that under operating conditions for complete suspension (1-s criterion) different flow conditions can exist. Thus the solid can e.g. form strands or local agglomerations, which have to be whirled up, or, however, be uniformly distributed over the entire bottom and must be brought into and maintained in suspension. It is thus to be expected that there will be two boundary laws to describe the suspension state at 1-s point. 

Fig. 5. 21 Relationship between the homogenization time t) and the suspension state in stirred tanks from [296]... 

Fig. 5.23 Dependence of the process characteristic of mass transfer upon suspension state from (210]... 

The solubility of the drug in the ointment base is approximately 0.05% w/w. It is present both in solution and in suspension in the higher concentration ointments. The relative proportions in the solution and suspension states depend on the ointment strength. Various reactions will be occurring simultaneously, especially if the degradation mechanism differs between the solution and suspension phase. 

One of its major advantages is that it allows the reaction between lead oxide and H2SO4 to proceed in a semi-suspension state (i.e. at densities between 3.20 and 3.50 g cm ). This method has been developed in our laboratory [34,35]. On completion of the crystallization process of basic lead sulfate, the semi-suspension can be concentrated through removal of the excess water (by evaporation under vacuum) until a paste of a desired density is obtained. 

Effect of air humidity on variations amplitude has been observed when long-term measurements of daily variations of currents. Slight variations of currents recorded from electrochemical cells filled with water have been observed at high humidity. This fact can be explained by absorbing ability of moisture present in the air in suspension state. Figure 6 illustrates action of high humidity on variation of currents in electrochemical cell with steel... 

The phase transition of ODA on silica can be also detected by a combination of suspension-state NMR... 

PAHs. This cannot be explained only by the increase of side-chain ordering, because it seems that there is no significant difference in the phase transition behavior between Sil-ODA and Sil-co-ODA in the mobile phase, as detected by differential scanning calorimetry (DSC) and suspension-state Therefore, we focus on the... 

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