Acoustic emission transducers were used to study the brush/rotor interface of a homopolar motor as a function of design parameters such as speed and load. The results indicate that acoustic emission is well suited for in situ monitoring of brush wear and rotor conditions, and for analyzing the tribological phenomena occurring at the brush/rotor interface. r 2007 Elsevier Ltd. All rights reserved.

We study acoustic emission avalanches during the process of failure of porous alumina samples (Al2O3) under compression. Specimens with different porosities ranging from 30% to 59% have been synthesized from a mixture of fine-grained alumina and graphite. The compressive strength as well as the characteristics of the acoustic activity have been determined. The statistical analysis of the record...

Due to the extensive use of composites in various industries and the fact that defects reduce ultimate strength and efficiency during operation, detection of failures in composite parts is very important. The aim of this paper is to use Acoustic Emission (AE) non-destructive method in four-point bending test of carbon/epoxy composite to analyze and examine the failure mechanisms. This method is...

Acoustic emission (AE) is one of the most recent entries into the field of nondestructive evaluation. Due to the uniqueness of the basic principle and the potential for tackling a wide range of applications, the technique has gone through rapid strides in a very short time. Thus, today, two decades after the first application of the technique, AE is used in various industries, such as petro-che...

Congenital Permanent Childhood Hearing Impairment (PCHI) is known to have a negative effect on language acquisition, cognitive development and social integration. Since 2000 our department has implemented a UNHS program in the West of Ireland. We describe our experience and detail our results to date. All neonates born from October 2000 to November 2007 were screened using a 2-stage protocol. T...

In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea current...

We report the discovery of one of the most powerful sunquakes detected to date, produced by an X1.2-class solar flare in active region 10720 on 2005 January 15. We used helioseismic holography to image the source of seismic waves emitted into the solar interior from the site of the flare. Acoustic egression power maps at 3 and 6 mHz with a 2 mHz bandpass reveal a compact acoustic source strongl...