RATIONALE AND OBJECTIVES Acoustic noise both in terms of its magnitude and frequency during magnetic resonance imaging (MRI) scan is influenced by imaging parameters and pulse sequences. It varies because of many different factors such as structure, materials, and magnetic field strength. The purpose of our study is to evaluate the characteristics of acoustic noise independent of MRI scan proto...

A short bipolar pressure pulse with "pancake" directivity is produced and propagated when an Ultra-High Energy (UHE) neutrino interacts with a nucleus in water. Nowadays, acoustic sensor networks are being deployed in deep seas to detect this phenomenon as a first step toward building a neutrino telescope. In order to study the feasibility of the method, it is critical to have a calibrator that...

Source localization is a crucial issue in underwater acoustics. Traditional matched field processing (MFP) use large vertical arrays to locate an underwater acoustic target. However, the use of the large arrays not only increases equipment and computational cost but also some problems such as element failures and array title degrades the localization performance. In this paper, the matched fiel...

Sounds from a U.S. Navy SSQ-110A source are received at high signal-to-noise ratios at ocean-basin scales at two Sound Surveillance Systems in the Pacific. The sounds have sufficient pulse resolution to study climatic variations of temperature. The acoustic data can be understood using ray and parabolic approximations to the wave equation. Modeled internal waves decrease pulse resolution from 0...

The aim of this study is to investigate the formation and ejection behavior of droplets created by a squeeze mode piezoelectric inkjet printing device using a single pulse voltage pattern. The test liquids are de-ionized (DI) water and ethylene glycol. The experimental results and acoustic wave theory are used to discuss the effects of operating frequency, positive voltage keeping time and puls...

Underwater Sensor Networks (UWSN) have many potential applications, such as ocean exploration, pollution monitoring, public safety and military underwater surveillance [1]. In all of these applications, localization plays an important rule since detected events must be tagged with position information. Moreover, position may also be required for geographical routing. GPS is not available in und...

Background and Methods: Guided by both spring and string ideas [1-3], we have previously investigated the manner in which sets of vibrational frequencies can be canceled by the appropriately designed gradient pulse. A picture of the cancellation of vibrations produced with a Lorentz impulsive force by an “anti-impulsive” follow-up force has emerged. This also provided a physical understanding o...

Ultrasound-mediated drug delivery is a nonchemical, nonviral, and noninvasive method for targeted transport of drugs and genes into cells. Molecules can be delivered into cells when ultrasound disrupts the cell membrane by a mechanism believed to involve cavitation. This study examined molecular uptake and cell viability in cell suspensions (DU145 prostate cancer and aortic smooth muscle cells)...

To date, there has been no dedicated study in Australian waters on the acoustics of killer whales. Hence no information has been published on the sounds produced by killer whales from this region. Here we present the first acoustical analysis of recordings collected off the Western Australian coast. Underwater sounds produced by Australian killer whales were recorded during the months of Februa...

This letter examines the propagation of an acoustic pulse in an elastic medium with weak quadratic nonlinearity. Both a displacement pulse and a stress pulse of arbitrary shapes are used to generate the wave motion in the solid. By obtaining the explicit solutions for arbitrary pulse shapes, it is shown that for a sinusoidal tone-burst, in addition to a second order harmonic field, a radiation ...