Dynamic mobility

Rawjee, Y. Y and Vigh, Gy., Efficiency optimization in capillary electrophoretic chiral separations using dynamic mobility matching, Anal. Chem., 66,3777,1994. 

Contreras A, Hale TK, Stenoien DL, Rosen JM, Mancini MA, Herrera RE (2003) The dynamic mobility of histone HI is regulated by cyclin/CDK phosphorylation. Mol Cell Biol 23(23) 8626-8636 Crosio C, Fimia GM, Loury R, Kimura M, Okano Y, Zhou H, Sen S, Allis CD, Sassone-Corsi P (2002) Mitotic phosphorylation of histone H3 spatio-temporal regulation by mammalian Aurora kinases. Mol Cell Biol 22(3) 874-885... 

Birkel, U., Gerold, G., and Niemeyer, J. (2002). Abiotic reactions of organics on clay mineral surfaces. In Soil Mineral-Organic Matter-Microorganism Interactions and Ecosystem Health Dynamics, Mobility and Transformation of Pollutants and Nutrients. Violante, A., Huang, P. M., Bollag, J.-M. and Gianfreda, L., eds., Elsevier Science B.V., Amsterdam,The Netherlands, pp. 437 447. 

We thus obtain the following expression for the dynamic mobility of a spherical polyelectrolyte ... 

Equation (25.45) is the required expression for the dynamic mobility of a soft particle, applicable for most practical cases. When co 0 fi 2, y 0, and F 0), Eq. (25.45) tends to Eq. (21.51) for the static case. When the polyelectrolyte layer... 

The original Acoustosizer used a single frequency whereas a later development has a range of 13 frequencies between 0.3 and 13 MHz. This allows the measurement of the dynamic mobility spectrum and the determination of the zeta potential and particle size. In order to invert the mobility spectrum into a size distribution a log-normal distribution of particle size is assumed. A comparison with photon correlation spectroscopy for determining particle size and laser Doppler anemometry for particle charge eonfirmed the results using ACS [266]. These and additional sedimentation measurements confirmed that changes in particle size and zeta potential due to dilution effects are likely to occur in aqueous and non-stabilized systems. 

Figure 7.19 Shear yield stress versus square of the zeta potential for the dispersions described in Fig. 7-18 at particle volume fractions (p = 0.184 and 0.213, or mass percentages of 57.0% and 61.4%. The zeta potential was obtained at low (p from the dynamic mobility. (From Leong et al. 1993, reproduced by permission of The Royal Society of Chemistry.)...

The dynamic mobility which is determined by the electro-acoustic effects differs from the low-frequency or DC mobility that is determined by electrophoresis... 

A linear relationship exists between the ESA or CVP amplitude and the volume fraction of the suspended particles. At relatively high-volume fractions, hydrodynamic and electric double-layer interactions lead to a non-linear dependence of these two effects on volume fraction. Generally, non-linear behavior can be expected when the electric double-layer thickness is comparable to the interparticle spacing. In most aqueous systems, where the electric double layer is thin relative to the particle radius, the electro-acoustic signal will remain linear with respect to volume fraction up to 10% by volume. At volume-fractions that are even higher, particle-particle interactions lead to a reduction in the dynamic mobility. 

Figure 2. Imaginary part of the complex susceptibility X (co) versus normalized frequency rjco for various values of the reaction field parameter. SoUd lines correspond to the matrix continued fraction solution, Eqs. (37) and (51) circles correspond to the smaU oscillation solution, Eq. (26) dashed lines correspond to the approximate small oscillation solution Eq. (53) and dotted lines correspond to the solution based on the dynamic mobility, Eq. (58).

The Smoluchowski formula, which is used in the AcoustoSizer from the measured dynamic mobility, is valid for a disperse suspension of spherical particles according to Eq. 1. 

AC) Electrophoresis is the motion of electrically charged particles under the influence of an AC electric field. For thin electrical double layers a Ad 1), dynamic mobility of spherical particles can be expressed as [9]... 

ESA is directly proportional to the dynamic mobility, whereas UVP requires knowledge of the high-frequency conductivity of the slurry. For this reason, ESA is frequently used for routine analysis of powder slurries under processing conditions [75]. An example of the application of ESA to powder characterization is given in Fig. 4, where the effect of surface cleaning on a SisN4 powder is evidenced by a shift in pHiep of the aqueous slurry. This shift is caused by a reduction of the surface oxide layer thickness. 

These in-situ generated emulsions aided in tertiary recovery by improving the areal sweep efficiency of the alkaline slug and by improving the dynamic mobility ratio within the core. 

The amount of Si ions dissolution is found to be dependent on surface modification, which was confirmed by induchvely coupled plasma-atomic emission spectrometer (ICP-AES) analysis. Table 2.2 shows the dissolution amount of Si ions with and without surface modification of fumed silica slurry. Without surface modification, the amount of Si dissoluhon was 1.370 0.002 mol/L, whereas surfaces modified with poly(vinylpyrrolidone) (PVP) polymer yielded a dissoluhon of 0.070 0.001 mol/L, almost 20 hmes less than the unmodified surface. Figure 2.6 represents the electro-kinetic behavior of silica characterized by electrosonic amplitude (ESA) with and without surface modification. When PVP polymer modified the silica surface, d5mamic mobility of silica particles showed a reduchon from -9 to -7 mobility units (10 m /Vxs). Dynamic mobility of silica particles lacking this passivation layer shows that silica suspensions exhibit negative surface potentials at pH values above 3.5, and reach a maximum potential at pH 9.0. However, beyond pH 9.0, the electrokinetic potential decreases with an increasing suspension pH. This effect is attributed to a compression of the electrical double layer due to the dissolution of Si ions, which resulted in an increase of ionic silicate species in solution and the presence of alkali ionic species. When the silica surface was modified by... 

The dynamic mobilities of the cationic and anionic side chain of amphoteric copolymers of poly(sodium-2-methacryloyloxyethanesulfonate-co-2-metha-cryloyloxyethyltrimethylammonium iodide) (NaMES-METMAI) were estimat-... 

However, it is important to note that the MRD experiments do not measure an explicit time correlation function that could characterize water dynamics occurring at different timescales. Thus it extracts only the average relaxation time of the system. It is interesting to note how these recent developments (particularly results from the NMRD technique and computer simulations) have changed our perception about the dynamics of the hydration layer, from a rigid ice-like layer to a dynamically mobile, somewhat slower than bulk but still active region. 

Conformational changes are expected to affect density (packing) and chain dynamics (mobility) such that surface/interface properties vary from that of the bulk glass. The surface effects are evident only within several chain segment diameters of the surface/interface 63), Chapter 6, by Haralampus et al., presents experimental and theoretical results on the effect of confinement on Tg. 

The particle property which is extracted from the measured ESA response is the dynamic mobility, of the drops. This is a complex quantity, having a magnitude and a phase angle (just as the ESA signal is a complex quantity). The magnitude of p j is analogous to the electrophoretic mobility obtained in, say, an electrophoresis experiment, where a d.c. field is applied. It is essentially determined by... 

To determine the precise relationship between the ESA signal and the dynamic mobility one must solve the set of differential equations given by O Brien in his 1990 paper (10). For the AcoustoSizer that problem is simplified by the geometry because the electrode dimensions and separation are both large compared to the wavelength of the sound (of millimeter order at the frequencies used). In that case the relation is given by O Brien et al. (12) as ... 

A. Relationship Between Dynamic Mobility and Particle Properties for Diiute Systems... 

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