Miniaturized therapeutic systems for ultrasound-modulated drug delivery to the central and peripheral nervous system

Ultrasound is a promising technology to address challenges in drug delivery, including limited drug penetration across physiological barriers and ineffective targeting. Here we provide an overview of the significant advances made in recent years in overcoming technical and pharmacological barriers using ultrasound-assisted drug delivery to...

Coupling Two Ultra-high-Speed Cameras to Elucidate Ultrasound Contrast-Mediated Imaging and Therapy

Ultrasound contrast-mediated medical imaging and therapy both rely on the dynamics of micron- and nanometer-sized ultrasound cavitation nuclei, such as phospholipid-coated microbubbles and phase-change droplets. Ultrasound cavitation nuclei respond non-linearly to ultrasound on a nanosecond time scale that necessitates the use of ultra-high...

Computational prediction of underwater radiated noise of cavitating marine propellers: On the accuracy of semi-empirical models

The potential impact of underwater radiated noise from maritime operations on marine fauna has become an important issue. The most dominant noise source on a propeller-driven vessel is propeller cavitation, producing both structure-borne and radiated noise, with a broad spectrum that covers a wide range of frequencies. To ensure acceptable...

On the use of synthetic inflow turbulence for scale-resolving simulations of wetted and cavitating flows

The Delft Twist 11 Hydrofoil is a common test case for investigating the interaction between turbulence and cavitation modelling in computational fluid dynamics. Despite repeated investigations, results reported for the lift and drag coefficient are accompanied by significant uncertainties, both in experimental and numerical studies. When...

Experimental and numerical study of cavitating flow around a surface mounted semi-circular cylinder

In this paper, the cavitating flow around a bluff body is studied both experimentally and numerically. The bluff body has a finite length with semi-circular cross section and is mounted on a surface in the throat of a converging-diverging channel. This set-up creates various 3D flow structures around the body, from cavitation inception to...

Bubble dynamics for broadband microrheology of complex fluids

Bubbles in complex fluids are often desirable, and sometimes simply inevitable, in the processing of formulated products. Bubbles can rise by buoyancy, grow or dissolve by mass transfer, and readily respond to changes in pressure, thereby applying a deformation to the surrounding complex fluid. The deformation field around a stationary,...

Control of cavitating flow over a 2D hydrofoil by active mass injection through a slot channel in its surface

We studied cavitating flow over the suction side of a symmetric 2D foil - a scaled-down model of high-pressure hydroturbine guide vanes (GV) - in different cavitation regimes at several attack angles. High-speed imaging was used to analyze spatial patterns and time dynamics of the gas-vapor cavities, as well as for evaluating the...

Void fraction measurements in partial cavitation regimes by X-ray computed tomography

Cavitation is a complicated multiphase phenomenon, where the production of vapor cavities leads to an opaque flow. Exploring the internal structures of the cavitating flows is one of the most significant challenges in this field of study. While it is not possible to visualize the interior of the cavity with visible light, we use X-ray...

Realization of high-Q/V photonic crystal cavities defined by an effective Aubry-André-Harper bichromatic potential

We report on the realization of high-Q/V photonic crystal cavities in thin silicon membranes, with resonances around 1.55 μm wavelength. The cavity designs are based on a recently proposed photonic crystal implementation of the Aubry-André-Harper bichromatic potential, defined from the superposition of two one-dimensional lattices with a non...

Effect of Ultrasound on Calcium Carbonate Crystallization

Scaling comprises the formation of hard mineral deposits on process or membrane equipment and calcium carbonate is the most common scaling salt. Especially in reverse osmosis (RO) membrane systems, scale formation has always been a serious limitation, causing flux decline, membrane degradation, loss of production and elevated operating costs. In...

VibroCav: Hydrodynamic Vibration and Cavitation Technology

Vibration and cavitation can be generated in many ways and serve many useful purposes. This study describes physical aspects of useful vibration and cavitation for a broad spectrum of applications at atmospheric or elevated pressures. After a review of available devices, hydrodynamic vibrating-body-in-pipe tools as described in patents by...

Hydrodynamic mechanisms controlling cavitation erosion