Microparticles, definition

The fluorescent molecule, CigRBH+, can be used as an alternative probe in the measurement of the interfacial viscosity of microparticles (about 0.5 mm in size) or rotating disks (several, 10 cm in radius) [29,30]. In comparison with the microparticles, the molecular probe has definite advantages. One of those is that the interference of the bulk viscosity is negligibly small and that information about the nano-environment around the probe can be obtained. 

In the Mint model, we have to take into account the following considerations (i) the initial filtration coefficient Xq, which is a parameter, presents a constant value after time and position (ii) the detachment coefficient, which is another constant parameter (iii) the quantity of the suspension treated by deep filtration depends on the quantity of the deposited solid in the bed this dependency is the result of the definition of the filtration coefficient (iv) the start of the deep bed filtration is not accompanied by an increase in the filtration efficiency. These considerations stress the inconsistencies of the Mint model 1. valid especially when the saturation with retained microparticles of the fixed bed is slow 2. unfeasible to explain the situations where the detachment depends on the retained solid concentration and /or on the flowing velocity 3. unfeasible when the velocity of the mobile phase inside the filtration bed, varies with time this occurrence is due to the solid deposition in the bed or to an increasing pressure when the filtration occurs with constant flow rate. Here below we come back to the development of the stochastic model for the deep filtration process. 

For the transformation of the stochastic model into a form, such as the Mint model, that allows the computation of Cx,g(x, r)/Cvo, we consider that this ratio gives a measure of the probability to locate the microparticle in the specified position P(x,t) = Pi(x,t) + P2(x,t). We can simplify our equations by eliminating probabilities Pi(x, r) and P2(x,t) with the use of this last definition and the rela-... 

In an emulsion, the particles of the internal phase are spherical or liquid droplets that are dispersed throughout a liquid external phase. Even though the particles may be liquid only at elevated temperatures (50-80° C) and semisolid or rigid at room temperature, as long as they appear spherical on careful microscopic examination, they are generally considered to be emulsified rather than suspended. Thus, a clue to the presence of a suspended particle is its lack of sphericity or its definitive lattice structure. Exceptions to this general rule are spherical microspheres and related spherical solid microparticles. 

Lipospheres were first reported by Domb, who described them as water-dispersible solid microparticles of a particle size between 0.2 and 100 pm in diameter, composed of a solid hydrophobic fat core stabilized by a monolayer of phospholipid molecules embedded in the microparticles surface [1], Using this definition, lipo-sphere size is on the nanometer scale. Usually, nanoscale particles consisting of a solid lipid core are termed SLN [16], though sometimes inconsistent nomenclature can be found. Unlike SLN, lipospheres are restricted to the stabilizing material of a phospholipid layer because of their definition [1], This chapter focuses on research results obtained for peptide and protein formulations termed lipospheres, and it does not consider SLN literature at large. 

Lindstrom, B., Microparticle flocculation is definitely a megatrend in the paper industry, Swedish Paper Journal, No. 1, January 1987. 

For our experiments we used a charge stabilized suspension of polystyrene spheres dispersed in ultrapure water (Batch No. PS-F-3390, Berlin Microparticles GmbH Germany). The diameter was determined by electron microscopy to be 590 nm. The size polydispersity was determined to be 5.8%. The particles are stabilized with CCX)H- and HSOq-groups and the effective charge was measured by conductivity to be Z = 3(XX) 100. For diluting of the stock solution to a definite volume fraction deionized water of a MilliQ water system was used. To adjust the salt concentration of the suspension NaCl was added to screen the interaction of the particles (typically 1 mM). 

Nanoparticles are, by definition, very small. It must be noted that the interparticle distance for nanoparticle-modified polymers is also very small, especially at high volume fi-actions. These factors may affect the interaction between a particle and its neighbors, or between a particle and the polymer surrounding it, or may affect the structure of the polymer itself. Hence, the properties of a particle-modified polymer may vary depending whether nanoparticles or microparticles are used. 

Fluorination [22] and chlorination [21] of diamond powders were carried out by Ando et al. without thermal activation for fluorine and with thermal activation for chlorine. Comparing the work with diamond films with that for powders shows that there are definite differences in reactivity. This is to be expected, because the surfaces of nanoparticles (or even microparticles) present a variety of crystallographic planes, as well as edges and corners. 

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