Ultrasonication is the most widely used technique for the dispersion of a range of nanomaterials, but the intrinsic mechanism which leads to stable solutions is poorly understood with procedures quoted in the literature typically specifying only extrinsic parameters such as nominal electrical input power and exposure time. Here we present new insights into the dispersion mechanism of a represen...

A novel rheometry termed ultrasonic spinning (USR) is overviewed in this paper. This methodology utilizes velocity profiling as a representative velocimetry for various complex fluids including multi-phase state. The USR determines optimal properties from cost function which calculated both equation of motion and constitutive test by substituting the measured profiles. Various examples are expl...

Ultrasound micro-molding technology has proved useful in processing biodegradable polymers with minimum material loss. This makes this technology particularly suitable for the production of biomedical microdevices. The use of silica (SiO2) nanoparticles is also interesting because of advantages like low cost and enhancement of final properties. Evaluation of the capacity to create a homogeneous...

Barium titanate ceramic powders have been incorporated in polyamide 11 to form homogeneous dispersion of particles in the matrix. Barium titanate/polyamide 11 nanocomposites have been synthesized using a solvent casting method with ultrasonic stirring to homogeneously disperse inclusions in the matrix. Composites with volume fraction of barium titanate / ranging from 0.01 to 0.4 were elaborated...

In this work, a model is proposed to predict acoustic waves generated in a homogeneous and isotropic cylindrical cavity by a laser line source. The Fourier series expansion is introduced for one spatial coordinate to solve this transient response problem. Theoretical displacements are obtained for an aluminum cylindrical cavity of internal diameter 40 mm. The corresponding displacements are obs...

The phase change thermal control method is now widely used in aircraft thermal protection due to its high energy density, constant temperature control, flexible operation, and many other advantages.1–6 However, thermal conductivity of most current phase change materials is low in phase transition process.7–10 This paper will add high thermal nanoparticles to phase change material in order to en...

Narrow band photoacoustics ~laser ultrasonics! are used to characterize the properties of free-standing nanometer-sized thin films. Photoacoustic generation is achieved by use of a microchip laser which deposits pulsed laser energy in the form of a spatially periodic source on the structure. The resulting narrow band ultrasonic modes are monitored using a Michelson interferometer. By varying th...

is considered which is used to describe tracer particles in turbulent flows, drifters in the upper ocean, cloud formation, ultrasonic aggregation of aerosols, mammal migration, iterating functions, and other phenomena. Here r, v are interpreted as the position and velocity of a particle with arbitrary initial conditions, τ is the Lagrangian correlation time, and w(t, r) is a Brownian motion in ...

Both the spectrum and correlation characteristics are important in constructing excitation sequences to realize the multichannel ultrasonic sensors working together. For LFM excitation sequence, there should not be too many simultaneously fired ultrasonic sensors, because of the limited available frequency band of the ultrasonic ranging system. The optimized CFM excitation sequences are propose...

In ultrasonic tube hydroforming, the tube is hydro formed while the ultrasonic vibration is applied to the die. Prior studies provide experimental proof that ultrasonic tube hydroforming reduces corner radius, improves lubrication and uniform thickness. Use of ultrasonic vibration can decrease friction at the tube-die interface. Few attempts have been made to analyze the wire drawing while the ...