the effect of mixing on rheological behavior of 6% wt epoxy-clay nanocomposites was studied. the mixing processes were carried out by low shear mixer, homogenizer and ultrasonic and combination of different mixing techniques at medium and maximum power. all these methods led to intercalated structure. the xrd results showed that the ultrasonic has the best effect on dispersion while a low shear...

Difficulties encountered in estimating the biodegradation of poorly water-soluble substances are often linked to their limited bioavailability to microorganisms. Many original bioavailability improvement methods (BIMs) have been described, but no global approach was proposed for a standardized comparison of these. The latter would be a valuable tool as part of a wider strategy for evaluating po...

Two ultrasonic nondestructive evaluation methods have been applied to systematically characterize the mechanical properties of nanostructured physical vapor deposited diamond-like carbon (DLC) ultra-hard coatings. A photoacoustic guided-wave technique is used to generate broadband surface acoustic waves (SAW) on the coating surfaces, and dispersion relations of the SAW for DLC coatings are meas...

Ultrasonic agitation is a very efficient method for deagglomeration and dispersion of ceramic slurries (alumina and barium titanate). The influence of parameters such as acoustic power, temperature, and treatment duration on the dispersion efficiency has been studied. For

Aiming at the problem that echo signal is hard to recognize caused by ultrasonic energy’s overquick dispersion and attenuation, a kind of ultrasonic horn is designed. According to the acoustic theory analysis, the ultrasonic horn can increase its radiation energy by improving impedance matching. The ultrasonic horn can make the directivity of sound source sharper and energy more centralized bec...

Dispersion stability of nanoparticles in the liquid media is of great importance to the utilization in practice. This study aims to investigate the effects of mechanical dispersion method on the dispersibility of functionalized TiO2 nanoparticles in the transformer oil. Dispersion methods, including stirring, ultrasonic bath, and probe processes, were systematically tested to verify their versa...

A double ultrasonic source has been shown to dramatically increase dispersion efficiency of carbon nanotubes. Thermal measurements of dispersing fluid only show temperature rises commensurate with the power levels of the two ultrasonic sources; which is validated by predictions of statistical energy analysis (SEA) based on wave superposition principles. In this paper, nonlinear wave resonance c...

This study focuses on measurements of clastic rocks ranging from 3 Hz up to 500 kHz in the laboratory and their application to well log analysis and a time-lapse study in the North Sea. Measurements of elastic properties over a large frequency spectrum can provide a better understanding of the dispersion and attenuation mechanisms in rocks and help to predict and model these effects. Sandstones...

A fine grain, relaxor-based piezoelectric ceramic 0.7 Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 (PMN-30% PT) has been investigated, which was fabricated using the columbite precursor method. The complete set of electromechanical properties of the piezoceramic at room temperature is determined using a combination of ultrasonic and resonance techniques. This fine-grain ceramic (grain size < or = 2.5 microm)...

This work considers the characterization of linear PVC acoustic properties using a linear ultrasonic measurement technique and the non-collinear ultrasonic wave mixing technique for measurement of the physical ageing state in PVC. The immersion pulse-echo measurements were used to evaluate phase velocity dispersion and attenuation of longitudinal waves in PVC test specimens. The suggested nonco...