Sono-crystallisation has been used to enhance crystalline product quality particularly in terms of purity, particle size and size distribution. In this work, the effect of impurities and ultrasound on crystallisation processes (nucleation temperature, yield) and crystal properties (crystal size distribution determined by Focused Beam Reflectance Measurement (FBRM), crystal habit, filtration rate and impurity content in the crystal product by Liquid Chromatography-Mass Spectroscopy (LC-MS)) were investigated in bulk suspension crystallisation experiments with and without the use of ultrasound. The results demonstrate that ultrasonic intervention has a significant effect on both crystallisation and product crystal properties. It increases the nucleation rate resulting in smaller particles and a narrower Particle Size Distribution (PSD), the yield has been shown to be increase as has the product purity. The effect of ultrasound is to reduce the level acetanilide impurity incorporated during growth from a 2 mol% solution of the selected impurity from 0.85 mol% to 0.35 mol% and likewise ultrasound reduces the uptake of metacetamol from 1.88 mol% to 1.52 mol%.

This study investigated the possible bactericidal acoustic effects of the dental ultrasonic scaler. Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis suspensions, were subjected to the vibrations of a Cavitron P1 insert for 2.5 and 5.0 min in an acoustically-simulated pocket model and the survivors enumerated. The extent of any cavitation occurring within the pocket model to which the statistically significant bactericidal activity observed might be attributed, was determined by 'sonoluminescence', which was then investigated by photomultiplication techniques. However, these failed to detect any sonoluminescence within the pocket space and, moreover, the necessary deflection of the water coolant away from the insert tip, to avoid flooding of the experimental pocket, proved to result in temperatures of 47.6 degrees C and 52.3 degrees C at the respective time intervals, and thereby constituted an alternative possible bactericidal mechanism. Examination of the effects of such temperature changes on the target bacteria then revealed statistically significant differences in the viable counts of both microorganisms after 5.0-min periods, and as such were comparable to those previously detected in relation to the pocket model. Whilst it must be presumed that the bacteriolytic effect observed in the main investigation was due to the incidental temperature changes, in the absence of acoustic cavitation the influence of any associated acoustic microstreaming cannot be discounted. Further investigations to assess the bactericidal potential of acoustic phenomena using a modified experimental to exclude any hyperthermic effects are therefore necessary.

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The effect of temperature on the behavior of 1-3 piezoelectric composites manufactured using various polymeric materials was assessed experimentally through electrical impedance analysis and laser vibrometry. Device behavior varied with temperature irrespective of the polymer filler. Most significant changes in the piezoelectric composites were recorded around the glass transition temperature (T/sub g/) of the polymer; movement to lower fundamental resonant frequencies and higher values of electrical impedance minima were observed at higher temperatures. Decoupling of the pillars from the polymer matrix was observed by laser vibrometry at high temperatures. The use of high T/sub g/ polymer extended the operational temperature range of a piezoelectric composite, and a high T/sub g/ polymer with improved thermal conductivity also proved beneficial. For all devices, at temperatures very close to room temperature, subtle changes in device performance, linked to polymer softening were observed. Particulate-filled materials have been investigated, and it is recognized that the high viscosities and low mechanical damping of such materials could be problematic for piezoelectric composite manufacture. The thermal solver of the PZFlex finite element code has been used to predict the temporal and spatial temperature response of a selection of the devices presented. The simulated and experimental data compare favorably

Abstract. Advances in manufacturing techniques and materials have led to an increase in the demand for reliable and robust inspection techniques to maintain safety critical features. The application of modelling methods to develop and evaluate inspections is becoming an essential tool for the NDE community. Current analytical methods are inadequate for simulation of arbitrary components and heterogeneous materials, such as anisotropic welds or composite structures. Finite element analysis software (FEA), such as PZFlex, can provide the ability to simulate the inspection of these arrangements, providing the ability to economically prototype and evaluate improved NDE methods. FEA is often seen as computationally expensive for ultrasound problems however, advances in computing power have made it a more viable tool. This paper aims to illustrate the capability of appropriate FEA to produce accurate simulations of ultrasonic array inspectionsminimizing the requirement for expensive test-piece fabrication. Validation is afforded via corroboration of the FE derived and experimentally generated data sets for a test-block comprising 1D and 2D defects. The modelling approach is extended to consider the more troublesome aspects of heterogeneous materials where defect dimensions can be of the same length scale as the grain structure. The model is used to facilitate the implementation of new ultrasonic array inspection methods for such materials. This is exemplified by considering the simulation of ultrasonic NDE in a weld structure in order to assess new approaches to imaging such structures.