Monodisperse particle size

Particle dissolution models, which presume spherical monodisperse particle size, inadequately depict the complexity of typical pharmaceutical powders. 

Figure 3.6 Silica spheres with monodisperse particle size are expensive analytical gels of top performance. Silica spheres with determined particle size ranges are ideally suited for preparative chromatography. (Photo courtesy of SiliCycle.)...

If all the particles in a sample are of the same size, then the powder is monodis-perse. Truly, the particles have more than one size in polydisperse samples. The monodisperse particle size distribution is more desirable than the polydisperse one. Therefore, the shape and surface area of the individual particles, the size ranges based on number or weight of particles, as well as the total surface area are variable. The commonly illustrated particle forms are sphere, rod, fiber, granular, cubical, flake, condensation Hoc, and aggregate. 

Simplifications in kinetic modeling with monodisperse particle sizes and separations, and the detailed characterization offered via [4] more systematic studies of the influence of these parameters can be made, and the associated kinetic modeling is then simplified and becomes more accurate. Furthermore, the active catalyst phase is in direct contact with the reacting gas [e.g., no pore diffusion needs to be accounted for, which simplifies mass transport calculations (when needed)]. 

When the polymer colloids possess monodisperse particle size distributions, they may exhibit true liquid crystallinity with Bragg diffraction in the visible region. This manifests itself in brilliant opalescence. 

M. Initiator system persulfate-bisulfite iron (PBI), with rate of initiation, R = 7.74 x 10 radicals /l/sec. Cross-hatched region indicates monodisperse particle size distributions.. 

Figo 7o Dependence of the particle number on sodium dodecyl sulfate concentration in aqueous phase polymerization of MMA at various monomer concentrations. Initial monomer concentrations, [M]q, are O 0,100, O 0,080M, Initiator system hydrogen peroxide-iron (II) (Fenton s reagent), with rate of initiation, R = lo6 x 10 radicals/l/seco Crosshatched region indicates monodisperse particle size distributions. 

N was calculated. The results are compared with values of N taken from the experiments where the SDS concentration was just sufficiently great to prevent primary particle flocculation and to give monodisperse particle size distributions. The remarkable agreement between experiment and theory is shown in Table IX. 

More uniform (ideally monodisperse) particle size distribution - determined by atomizer design... 

Rgure 7.3. A schematic representation for a continuous emulsion polymerization process, in which the relatively monodisperse particle size distribution of seed latex particles introduced into a continuous stirred tank reactor becomes broader at the exit of the reactor. 

Table 5 Number of Particles per Cubic Meter as a Function of Monodisperse Particle Size for Three Radioactive Materials at Their Derived Air Coneentration (DAC)...

The spontaneous formation, almost monodisperse particle size, and thermodynamic stabUity of microemulsions make them very attractive for applications that involve oil/water mixtures. In many cases, almost transparent systems also provide a degree of a esthetic appeal. 

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