A strong laser pulse that is focused into a liquid produces a vapor cavity, which first expands and then collapses with subsequent rebounds. In this paper a mathematical model of the spherically symmetric motion of a laser-induced bubble is proposed. It describes gas and liquid dynamics including compressibility, heat, and mass transfer effects and nonequilibrium processes of evaporation and condensation on the bubble wall. It accounts also for the occurrence of supercritical conditions at collapse. Numerical investigations of the collapse and first rebound have been carried out for different bubble sizes. The results show a fairly good agreement with experimental measurements of the bubble radius evolution and the intensity of the outgoing shock wave emitted at collapse. Calculations with a small amount of noncondensable gas inside the bubble show its strong influence on the dynamics.

The mutual interaction between small oscillating cavitation bubbles ${(R}_0<10\mathrm{}\mu \mathrm{m})$ in a strong acoustic field ($P_a>1\mathrm{}\mathrm{bar},$ $f=20\mathrm{}\mathrm{kHz}$) is investigated numerically. We assume spherical symmetry and a coupling of the bubble oscillations. Our results show that the strength and even the directions of the resulting secondary Bjerknes forces differ considerably from predictions of the well-known linear theory. This is of immediate consequence for understanding and modeling structure formation processes in acoustic cavitation and multibubble sonoluminescence.

Pultrusion is one of the most efficient methods of producing polymer composite structures with a constant cross-section. Pultruded profiles are widely used in bridge construction, transportation industry, energy sector, and civil and architectural engineering. However, in spite of the many advantages thermoplastic composites have over the thermoset ones, the thermoplastic pultrusion market demonstrates significantly lower production volumes as compared to those of the thermoset one. Examining the thermoplastic pultrusion processes, raw materials, mechanical properties of thermoplastic composites, process simulation techniques, patents, and applications of thermoplastic pultrusion, this overview aims to analyze the existing gap between thermoset and thermoplastic pultrusions in order to promote the development of the latter one. Therefore, observing thermoplastic pultrusion from a new perspective, we intend to identify current shortcomings and issues, and to propose future research and application directions.

Bubble clouds forming in an extended volume of liquid in acoustic cavitation show a slowly varying filamentary structure, whose origin is still not completely understood. Experimental observations are reported that provide some characteristics of the phenomenon, such as bubble distributions and sound–field measurements. A discussion of relevant physical interactions in bubbly liquids is comprised of wave dynamics, Bjerknes and drag forces, nucleation and coalescence. For describing the structure formation process, continuum and particle approaches are employed. In the framework of the continuum model it is shown that homogeneous bubble distributions are unstable, and regions with high bubble concentration emerge in the course of a self–concentration process. In the particle model, all bubbles are treated as interacting objects that move in the liquid. This approach is complementary to the continuum model. It allows the inclusion of some particular features, for instance Bjerknes forces based on nonlinear bubble oscillations. Both models are discussed and results are compared with experimentally observed patterns.

Aerosol-based direct-write refers to the additive process of printing CAD/CAM features from an apparatus which creates a liquid or solid aerosol beam. Direct-write technologies are poised to become useful tools in the microelectronics industry for rapid prototyping of components such as interconnects, sensors, and thin film transistors (TFTs), with new applications for aerosol direct-write being rapidly conceived. This paper aims to review direct-write technologies, with an emphasis on aerosol-based systems. The different currently available state-of-the-art systems such as Aerosol Jet CAB-DW, MCS, and aerodynamic lenses are described. A review and analysis of the physics behind the fluid-particle interactions including Stokes and Saffman force, experimental observations, and how a full understanding of theory and experiments can lead to new technology are presented. Finally, the applications of aerosol direct-write for microelectronics are discussed.