Hydrodynamic particle size

In this model, the buoyant mass is then the sum of the buoyant mass of the three components, assuming that these are independent of the mass of solvent occupied in the solvation shell. Thus, the mass of the adsorbed shell can be calculated if information about the mass and density of the core particle and the density of the macromolecule and solvent are known. Photon correlation spectroscopy, electron microscopy, flow FFF, or other sizing techniques can readily provide some independent information on the physical or hydrodynamic particle size, and pycnometry can be used to measure the densities of the colloidal suspension, polymer solution, and pure liquid. 

As in the case of emulsion polymerization, an increase in the functional monomer concentration leads to a reduction in the hnal hydrodynamic particle size and enhanced water-solnble polymer formation, as illustrated in Fignres 12.14 and 12.15 for batch polymerization of (NIP-MAM/MBA/IDA/KPS). The rednction in particle size vs. functional monomer has been attribnted to the enhancement of precnrsor formation and the number of stable particles which rapidly become the polymerization loci. 

FIGURE 12.18 Reduced particle size of poly(NlPAM) and poly(NIPMAM) as a function of temperature using QELS at 1 mM NaCl. f)2o c are the hydrodynamic particle size at 20°C and at a given temperature... 

The particle size of silica-chitosan composite nanoparticles increased slightly from about 10 to 14 nm with a reaction time of 15 to 360 min. The silica-chitosan nanoparticles prepared after different hours of reaction are designated as silica-chitosan 1H-6H (nanoparticles) in the rest of the discussion. The hydrodynamic particle sizes of silica from silicate were 188.3 11.5 nm and of silica from TEOS were 236.3 6.85 nm. The hydrodynamic particle size of silica-chitosan composite nanoparticles increased slightly from about 153 to 177 nm with a reaction time of 15 to 360 min. 

This chapter relates aerosol and hydrodynamic particle size to in vivo deposition, phagocytosis, and release of cytokines. We are interested in comparing these properties in ultrafine particles (nanoparticles <100nm) with those in the accumulation fraction (100 to 600 nm), the intermodal fraction (600 to 2500 nm) of fine particles and the coarse firaction (2500 to 10,000 nm). We expect the most interesting comparison to be between the minimally aggregated ultrafine particles (nanoparticles) and moderately aggregated accumulation fraction of the fine particles. 

Define hydrodynamic particle size and particle size in air. How are the differences in definition important to predicting risk to lung ... 

Below a certain permeation rate, the TMP varies linearly with flux, and above this transition flux, a sharp increase in TMP is observed concomitant with a permeate flux decline. A time-dependent flux decline is also observed. The critical flux hypothesis is that upon start-up, there exists a flux below which a time-dependent flux decline does not occur, whereas fouling takes place above this critical value [44]. It is known that the critical flux in MBRs depends on hydrodynamics, particle size, and membrane surface characteristics. Typically, MBRs are operated below the critical flux in order to minimize fouling. However, the validity of the critical flux concept in MBR operation has been questioned since after prolonged operation, irreversible fouling has been observed at subcritical fluxes [45]. 

The concept of critical flux was introduced in the mid-1990s by Field et al (1995) to overcome membrane fouling problems. Below the critical flux the decline of flux with time does not occur and membrane fouling can be neglected. Therefore, the selection of an adequate initial permeate flux or TMP is very important. The value of the critical flux depends on hydrodynamics, particle size, interactions between colloids and membrane and suspension properties (pH, salinity, conductivity) (Kwon et al, 2000). A constant permeate flux rather than a constant TMP seems to be a good option to avoid membrane fouling in ceramic membranes used with an MBR (Defrance and Jaffrin, 1999). 

Fig. 11 Average hydrodynamic particle size rfi, (top) and polydispersity index (PI) (bottom) of the studied stable PEC dispersions in dependence on the molar ratio n—ln+. PDADMAC (PD) as PC is combined with a commercial polyacrylamide copolymer (PR2540) ...

The hydrodynamic particle size distribution of samples was measured by dynamic light scattering (DLS-700, Otsuka Electronics) for the sample-redispersed aqueous suspension containing a small amount of sodium dodecyl sulphate as a dispersion stabilizer. The... 

There are few reports on the influence of initiator on the precipitation polymerization but as expected, the polymerization rate (Figure 9.8) increases together with the initiator concentration, as is often the case in emulsion polymerization. This behavior is attributed to an increase in the polymerization loci. It is interesting to notice that an increase in the initiator concentration leads to an increase in the water-soluble polymer formation (oligomers bearing low molecular weight) and to a decrease in the final hydrodynamic particle size (for low initiator concentrations). The polymerization rate (Rp) is related to the initiator concentration [/] using the low-scale representation ... 

A systematic analysis of the foam spray drying process, including investigations of spray hydrodynamics (particle size distribution, particle velocity, centricity), heat and mass transfer between the phases, drying kinetics and the effects of feed foaming on final product properties, was carried out by Zbicinski and Rabaeva (2010) and Rabaeva (2012). 

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