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Nanometrically-smooth infrared silicon optics can be manufactured by the diamond turning process. Due to its relatively low density, silicon is an ideal optical material for weight sensitive infrared (IR) applications. However, rapid diamond tool edge degradation and the effect on the achieved surface have prevented significant exploitation. With the aim of developing a process model to optimise the diamond turning of silicon optics, a series of experimental trials were devised using two ultra-precision diamond turning machines. Single crystal silicon specimens <1, 1, 1> were repeatedly machined using diamond tools of the same specification until the onset of surface brittle fracture. Two cutting fluids were tested. The cutting forces were monitored and the wear morphology of the tool edge was studied by scanning electron microscopy (SEM).

Bagasse agave tequilana fibres (ATF), an abundant by-product of Mexican tequila production, were characterised, treated and investigated as a reinforcement and filler material for polylactic acid (PLA) green composites.Two fibre pre-treatments were investigated: alkali (8% NaOH solution) and enzymatic (0.4% Pectate lyase solution). Composites pellets of 20, 40 and 60 % (w/v) of ATF in PLA were manufactured using extrusion moulding. Press moulding was used to fabricate samples composite plates. Tensile, flexural, impact and water absorption properties were investigated on machined samples.

A series of fine‐grade alumina powders has been used in combination with maize starch granules to produce porous structures for porous hydrostatic journal‐bearing applications. A comprehensive series of tests was conducted to characterize porosity in terms of density, pore size, and permeability. Successful processing of quality journal‐bearing components has been demonstrated for preferred combinations of alumina size and starch content, using fixed‐processing parameters. The new porous ceramic bearings showed consistent and reproducible properties and are suitable for a wide range of higher precision engineering applications. The porous ceramic‐bearing processing route has also proved to be low cost and environmentally sound.

Carbon nanotubes (CNTs) embedded polymers are of increasing interest to scientific and industrial communities for multi-functional applications. In this article, CNTs have been introduced to high-strength epoxy adhesive for enabling in-situ strain sensing in adhesively bonded aluminium-to-aluminium single-lap joints to accurately indicate the onset and propagation of adhesion failure to the evolution of piezo-resistivity in varying mechanical loads. The CNT modified adhesive in bonded joints and the CNT modified adhesive alone have been tested under monothonic and cyclic tensile loads up to ultimate failure. The changes in the piezo-resistivity induced by the CNTs have been monitored in situ with respect to loading. A novel interpretation method has been developed for progressive, instantaneous adhesion failure estimation under cyclic tensile stresses from a resistivity baseline. The method indicates that the in-situ resistivity changes and the rate of the changes with strain, i.e. sensitivity, strongly correlate with the adhesion failure progression, irrespective of the CNT dispersion quality. Moreover, the effect of bond thickness on the evolution of piezo-resistivity and adhesion failure have been studied. It was observed that relatively thin adhesive bonds (0.18 mm thickness), possessing higher CNT contact points than thick bonds (0.43 mm thickness), provide 100 times higher sensitivity to varying cyclic loads.