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A novel fibre optic sensor system has been developed for detection of acoustic emission. The sensor design was based on a 2×2 fused tapered optical fibre coupler configuration. Given the intended use of this sensor for the detection of acoustic emission in smart materials and structures, its lightweight, compatibility with composite material and immunity from electromagnetic interference are great advantages. Apart from the performance specification and reliability, the overall cost of the sensor system is a major factor in their adoption by end-users. The manufacturing of this sensor is low-cost and the signal output from the sensor system developed can be directly fed to the commercial AE acquisition system. The demonstration of acoustic emission detection was conducted using fibre coupler-based AE sensors in different materials and structures. The AE sources are various and depend on the different applications. In the current paper, we report on the use of the fibre optic AE sensor system for concrete damage monitoring. An experiment on damage detection on a composite plate with this fibre optical AE sensor is also reported in the paper.

The imaging of very fine oxide particles (<10 nm) in a copper matrix using field-ion microscopy is described. The observed particle sizes in the wire field-ion samples are related to particle sizes measured in thin foils of strip samples by transmission electron microscopy.

Reticulated targets of deuterated triglycine sulphate have been made by ion beam etching. The use of these targets in the pyroelectric vidicon has resulted in significant improvement in the thermal m.t.f. and M.R.T.

The spatial resolution of the pyroelectric vidicon may be significantly improved by reticulation of the pyroelectric target. This paper describes the development of techniques and structures for the preparation of high quality reticulated vidicon targets in deuterated triglycine sulphate (DTGS).The dimensions of the reticulated target structures were selected using the results of a theoretical analysis. Reticulated targets were prepared by low energy ion-beam milling of thin targets of DTGS. The ion-beam etching characteristics of this material are described and the selection of masking materials, support layers and the signal electrode are discussed. Large numbers of targets were scanned in vidicon tubes so that differences in imaging performance and cosmetic appearance could be correlated to changes made to the target configuration and etching process. From this study an optimum target preparation and processing route was developed which provided significant improvement in resolution over tubes possessing planar targets, and also gave acceptable image appearance.

Abstract: The results of a metallographic study of the growth of an oxide denuded surface zone and the concurrent particle coarsening which occurs during high temperature annealing of internally oxidized silver-cadmium alloys are presented. A theoretical analysis for the growth of the denuded zone is derived and verified. The kinetic parameters measured for the growth of this zone yield values for the product of the solubility of the oxide particles, Cs, and the diffusion coefficient of cadmium, DCd, which may be utilized directly in analysis of the particle coarsening kinetics. An analysis of the coarsening kinetics of the cadmium oxide particles is presented and a value for the interfacial energy between the oxide and the silver matrix of 450 mJ/m2 is derived.

This paper describes the development of a novel electrical contact material, silver-ruthenium oxide, for use in light duty switching applications where low contact resistance values must be maintained. Material fabrication and contact resistance behaviour after exposure to a tarnishing atmosphere are described. An explanation for the low contact resistance values obtained for silver-ruthenium dioxide in comparison with pure silver is offered.

This paper discusses the preparation techniques which can be used for the examination of thick film resistor microstructures by Transmission Electron Microscopy. The application of this technique, including High Voltage Electron Microscopy and Electron Microscope Mass Analysis, to both Ruthenium Dioxide and Bismuth Ruthenate based thick film resistors, is considered.