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Ultrasonic atomization is employed to generate size-controllable droplets for a variety of applications. Here, we minimize the number of parameters dictating the process by studying the atomization of a single drop pending from an ultrasonic horn. Spatiotemporally resolved X-ray phase-contrast imaging measurements show that the number-median sizes of the ejected droplets can be predicted by the linear Navier–Stokes equations, signifying that the size distribution is controlled by the fluid properties and the driving frequency. Experiments with larger pendant water drops indicate that the fluid–structure interaction plays a pivotal role in determining the ejection onset of the pendant drop. The atomization of viscoelastic drops is dictated by extended ligament formation, entrainment of air, and ejection of drop-encapsulated bubbles. Existing scaling laws are used to explain the required higher input amplitudes for the complete atomization of viscoelastic drops as compared to inviscid drops. Finally, we elucidate the differences between capillary wave-based and cavitation-based atomization and show that inducing cavitation and strong bubble oscillations quickens the onset of daughter drop ejection but impedes their size control. [Display omitted] • Time-resolved X-ray phase-contrast imaging of ultrasonic drop atomization. • Drop atomization is driven by surface capillary waves and not by cavitation. • Onset of daughter drop ejection is dictated by the fluid–structure interaction. • Viscoelastic drops require higher input amplitudes for complete atomization. • Cavitation-related mechanisms quicken ejection onset but impede production control. [ABSTRACT FROM AUTHOR]

Highlights: [•] DB induced apoptosis and suppressed the growth of human non-Hodgkin lymphoma cells. [•] Mitochondrial membrane potential was decreased by DB. [•] DB activated FADD, caspases in the death receptor pathway. [ABSTRACT FROM AUTHOR]

• Air-water two-phase flow tests were carried out in a 3 × 3 rod bundle channel. • Global and local void fraction data were measured, benchmarked and validated. • PDF, FFT, averages and standard deviations were obtained for dynamic analysis. • Local/global void distributions under different flow conditions were presented. • A set of empirical correlations for estimating local void fractions were proposed. In this study, the vertical upward air–water two-phase flow tests have been carried out to investigate the distribution of local and global void fractions in a rod bundle channel under low-flow conditions. The height of the rod bundle channel is about 5 m, and the channel cross section is comprised of a 52 × 52 mm rectangular casing and 3 × 3 circular rods. The rods with a diameter of 11.5 mm and a pitch of 15.4 mm were set as a rectangular array. Four sets of non-intrusive conductivity sensors were built to measure the local and global void fractions of various gaps within the rod bundle channel. The tests were operated at low flow conditions: j g = 0.016–0.92 m/s and j f = 0.02–0.05 m/s, which covered the possible flow regimes of bubbly, cap-bubbly and cap-turbulent flows. The measured global void fraction were benchmarked with existing one-dimensional drift-flux model, and the local void fractions have been summed up by regions and compared with the global void fraction for validation. The dynamic characteristics of local/global void fractions have been analyzed with probability density function (PDF) and fast Fourier transform (FFT), and the distributions and variations of averaged void fraction against test conditions have been presented. Furthermore, the empirical correlations for estimating the local void fractions have been proposed, which can successfully estimate the local void distribution from global void fraction with limited errors. The present results and correlations can be a reference for future development and modification of detailed two-phase flow models in the rod bundle geometry. [ABSTRACT FROM AUTHOR]