Application of the small punch test to evaluate the integrity of a cold spray titanium coating

Metal Cold Spray (MCS) is currently under evaluation for its suitability for aerospace applications. However, before this technology can be implemented into the jet engine, the mechanical performance and structural integrity of this novel process must be fully understood. Limited data is currently available to determine key materials properties given the discrete and transient nature of a MCS component. Furthermore, it is extremely challenging to produce uniaxial test coupons that are truly representative of the in-service geometry. As such, the small punch (SP) test offers an attractive alternative, since miniature disc SP specimens can be extracted from localised discrete locations. This paper will report the findings from an experimental collaborative programme of work currently being undertaken by Swansea University, Rolls-Royce Singapore and Nanyang Technological University Corp Lab to understand the contrasting modes of failure in a Ti-6Al-4V coating sprayed on to a Ti-6Al-4V substrate, which is expected to have properties akin to a forged variant. This will include a series of SP tests to assess the integrity and performance across the substrate, bond line and coating. Results will be supported by additional microstructural and fractographic investigations

Localized laser assisted eutectic bonding of quartz and silicon by Nd:YAG pulsed-laser

10.1016/j.sna.2004.11.035Sensors and Actuators, A: Physical1202550-561SAAP

Characterization of localized laser assisted eutectic bonds

10.1016/j.sna.2005.07.006Sensors and Actuators, A: Physical1252573-585SAAP

Distinguishing fall activities from normal activities by angular rate characteristics and high-speed camera characterization

10.1016/j.medengphy.2005.11.008Medical Engineering and Physics288842-849MEPH

Clinical validation of a customized multiple signature microarray for breast cancer

10.1158/1078-0432.CCR-07-0999Clinical Cancer Research142461-469CCRE

Sex-Specific ADHD-like Behaviour, Altered Metabolic Functions, and Altered EEG Activity in Sialyltransferase ST3GAL5-Deficient Mice

A deficiency in GM3-derived gangliosides, resulting from a lack of lactosylceramide-alpha-2,3-sialyltransferase (ST3GAL5), leads to severe neuropathology, including epilepsy and metabolic abnormalities. Disruption of ganglioside production by this enzyme may also have a role in the development of neuropsychiatric disorders. ST3Gal5 knock-out (St3gal5(-/-)) mice lack a-, b-, and c-series gangliosides, but exhibit no overt neuropathology, possibly owing to the production of compensatory 0-series glycosphingolipids. Here, we sought to investigate the possibility that St3gal5(-/-) mice might exhibit attention-deficit/hyperactivity disorder (ADHD)-like behaviours. In addition, we evaluated potential metabolic and electroencephalogram (EEG) abnormalities. St3gal5(-/-) mice were subjected to behavioural testing, glucose tolerance tests, and the levels of expression of brain and peripheral A and B isoforms of the insulin receptor (IR) were measured. We found that St3gal5(-/-) mice exhibit locomotor hyperactivity, impulsivity, neophobia, and anxiety-like behavior. The genotype also altered blood glucose levels and glucose tolerance. A sex bias was consistently found in relation to body mass and peripheral IR expression. Analysis of the EEG revealed an increase in amplitude in St3gal5(-/-) mice. Together, St3gal5(-/-) mice exhibit ADHD-like behaviours, altered metabolic and EEG measures providing a useful platform for better understanding of the contribution of brain gangliosides to ADHD and associated comorbidities

Effects of working gas on wear and corrosion resistances of cold sprayed Ti-6Al-4V coatings

In this study, the wear and corrosion resistances of cold sprayed Ti-6Al-4V (Ti64) coatings on commercial Ti64 substrates using nitrogen (N2) and helium (He) working gases were systematically investigated. The denser microstructure of the Ti64 coating with a lower porosity level was achieved with He working gas. Therefore, the Ti64 coating deposited with He working gas had the higher hardness than the one deposited with N2 working gas. The Ti64 coating deposited with He working gas had higher adhesion strength than the one deposited with N2 working gas. The tribological results showed that the use of He working gas during the cold spraying gave rise to the higher abrasive wear resistance of the Ti64 coating via its higher hardness. In addition, the Ti64 coating deposited with He working gas did not show any fatigue micro-cracks on its wear track during the prolonged sliding probably due to the relatively strong bonding between sprayed Ti64 particles. It was found that the Ti64 coating deposited with He working gas had lower anodic dissolution in 0.6 M NaCl solution compared to the one deposited with N2 working gas as a result of its lower porosity level