Microfluidics based on ZnO/nanocrystalline diamond surface acoustic wave devices

Surface acoustic wave (SAW) devices with 64 μm wavelength were fabricated on a zinc oxide (ZnO) film deposited on top of an ultra-smooth nanocrystalline diamond (UNCD) layer. The smooth surface of the UNCD film allowed the growth of the ZnO film with excellent c-axis orientation and low surface roughness, suitable for SAW fabrication, and could restrain the wave from significantly dissipating into the substrate. The frequency response of the fabricated devices was characterized and a Rayleigh mode was observed at ∼65.4 MHz. This mode was utilised to demonstrate that the ZnO/UNCD SAW device can be successfully used for microfluidic applications. Streaming, pumping, and jetting using microdroplets of 0.5 and 20 μl were achieved and characterized under different powers applied to the SAW device, focusing more on the jetting behaviors induced by the ZnO SAW.     

Do high scores on the Adolescent‐School Problems and Immaturity Scales of the MMPI‐A have implications for cognitive performance as measured by the WISC‐III?

High scores on the Adolescent‐School Problems (A‐Sch) content scale and the Immaturity (IMM) supplementary scale of the MMPI‐A have been associated with poor school performance and possible learning disabilities (Archer, 1997). The aim of the present study was to determine whether these scales were associated with cognitive performance as measured by the WISC‐III. Subjects completed the Wechsler Intelligence Scale for Children, Third Edition (WISC‐III) and the MMPI‐A. Their scores for the WISC‐III sub‐tests and SCAD were calculated. The A‐Sch content and the IMM supplementary scales were extracted from the MMPI‐A. The results indicated that A‐Sch was associated with lower WISC‐III scores in males and predicted poorer performance in Full Scale IQ (FIQ), Verbal IQ (VIQ), Information, and Arithmetic. For females however, there was little evidence to suggest a relationship between A‐Sch and cognitive performance. The association between IMM and the WISC‐III sub‐tests was found to be a result of its correlation with A‐Sch. The implications of these findings, in particular, those involving gender differences, were discussed. © 1999 John Wiley & Sons, Inc.     

An assessment of the strength of knots and splices used as eye terminations in a sailing environment

Research into knots, splices and other methods of forming an eye termination has been limited, despite the fact that they are essential and strongly affect the performance of a rope. The aim of this study was to carry out a comprehensive initial assessment of the breaking strength of eye terminations commonly used in a sailing environment, thereby providing direction for further work in the field. Supports for use in a regular tensile testing machine were specially developed to allow individual testing of each sample and a realistic spread of statistical data to be obtained. Over 180 break tests were carried out on four knots (the bowline, double bowline, figure-of-eight loop and perfection loop) and two splices (three-strand eye splice and braid-on-braid splice). The factors affecting their strength were investigated. A statistical approach to the analysis of the results was adopted. The type of knot was found to have a significant effect on the strength. This same effect was seen in both types of rope construction (three-strand and braid-on-braid). Conclusions were also drawn as to the effect of splice length, eye size, manufacturer and rope diameter on the breaking strength of splices. Areas of development and further investigation were identified.     

Metaphors as global markers for teachers' beliefs about the nature of science

In this paper, we report an analysis of metaphors used by three science teachers in their classroom discourse and consider the implications of this research for the image of science that students are likely to construct. Teacher beliefs about the nature of science are implicit and entrenched and may be contrary to both contemporary philosophies of science and constructivist theory. We argue that the presence of metaphors such ateaching as a journey, knowledge as object andteacher as pathfinder in teachers' classroom discourse signify the implicit existence of a powerful objectivist epistemology that governs teachers' pedagogies. If students are to construct contemporary views of the nature of science and if constuctivist pedagogy is to develop in the science classroom then science teachers need to reflect on their use of these role-determining objectivist metaphors.