Ultrasonic wave propagation in colloid suspensions and emulsions: recent experimental results

The NDE of Complex Liquids Containing Suspended Particles

“…In earlier publications we have reported excellent agreement between the Allegra and Hawley model, and other theoretical formulations in some cases, with experimental measurements in suspensions of polystyrene spheres [11], silica spheres [11], iron spheres [12], Ti0 2 [12] and kaolin [13]. In this paper we present new data on aqueous suspensions of silica spheres, an ultrasonic study of flocculation and network formation in an aqueous emulsion of I-bromohexadecane, and the results of an experiment to crystallize CuS0 4 from aqueous solution.…”

“…In earlier work [11,12], we have demonstrated that scattering theory, and in some cases hydrodynamic theories, can give precise simulations of ultrasonic compression wave absorption coefficient a(w) and phase velocity c(w) as functions of frequency. In this paper we have extended this work to examine the applicability of the Allegra and Hawley scattering model [6] to aqueous suspensions of small (300m diameter) silica spheres; we have shown that the model as it stands produces an over estimate of absorption, and that if it is adapted so as to include an anomalous viscosity which is a rising function of frequency in the tens of MHz region, then good agreement is obtained with experimental data which we regard as reliable.…”

Modeling ultrasonic attenuation coefficient and comparative study with the principal theoretical models of biphasic suspensions

“…The Allegra and Hawley model can be reformulated for solid-solid dispersions. The diffusion coefficients An, have been incorporated into theories of multiple diffusion [11][12], by Holmes et al [13][14]. Both of theses models can be slightly modified to reflect the suspensions that have different particle size distributions.…”

“…Harker and Temple included a term effective viscosity given by Equation 14: (14) This term takes into account the effect of particles on the real viscosity of the liquid. It is a function of the volume fraction of the dispersed phase, the particle geometry and fluid viscosity.…”

Ultrasonic Characterisation of W/O Microemulsions - Structure, Phase Diagrams, State of Water in Nano-Droplets, Encapsulated Proteins, Enzymes

“…Figure 1(c) demonstrates the dependence of compressibility of aqueous droplets on their particle size in the IPM system at 0.01 sp w  calculated using the PSize software module (v.2.28.01) provided with HR-US 102 spectrometers (Sonas Technologies Ltd.). This software utilises theoretical approaches developed previously for spherical particles in liquid continuous medium (Epstein & Carhart, 1953;Waterman & Truell, 1961;Allegra & Hawley, 1972;Povey, 1997;Austin et al, 1996). The physical properties used in the calculations are given in Table 1.…”