Three-dimensional displacement mapping of diffused Pt thermal barrier coatings via synchrotron X-ray computed tomography and digital volume correlation

A progressive study of the three-dimensional deformation field within a γ/γ′ thermal barrier coating following cyclic oxidation at 1200 °C is presented, observed using synchrotron X-ray micro-computed tomography and analysed by digital volume correlation. Oxide thickening and bond coat creep displacements are quantified as a function of exposure time at temperature. Linear gradients of these displacements are measured both in-plane and normal to the oxide layer. The first thermal cycle shows the most displacement changes; destructive sectioning confirms the DVC-calculated displacement magnitudes

Of risks and regulations: how leading U.S. nanoscientists form policy stances about nanotechnology

Even though there is a high degree of scientific uncertainty about the risks of nanotechnology, many scholars have argued that policy-making cannot be placed on hold until risk assessments are complete (Faunce, Med J Aust 186(4):189–191, 2007; Kuzma, J Nanopart Res 9(1):165–182, 2007; O’Brien and Cummins, Hum Ecol Risk Assess 14(3):568–592, 2008; Powell et al., Environ Manag 42(3):426–443, 2008). In the absence of risk assessment data, decision makers often rely on scientists’ input about risks and regulation to make policy decisions. The research we present here goes beyond the earlier descriptive studies about nanotechnology regulation to explore the heuristics that the leading U.S. nanoscientists use when they make policy decisions about regulating nanotechnology. In particular, we explore the relationship between nanoscientists’ risk and benefit perceptions and their support for nanotech regulation. We conclude that nanoscientists are more supportive of regulating nanotechnology when they perceive higher levels of risks; yet, their perceived benefits about nanotechnology do not significantly impact their support for nanotech regulation. We also find some gender and disciplinary differences among the nanoscientists. Males are less supportive of nanotech regulation than their female peers and materials scientists are more supportive of nanotechnology regulation than scientists in other fields. Lastly, our findings illustrate that the leading U.S. nanoscientists see the areas of surveillance/privacy, human enhancement, medicine, and environment as the nanotech application areas that are most in need of new regulations

Methods to reduce the thermal conductivity of EB-PVD TBCs.

This paper reviews the advantages and disadvantages of various thermal barrier coating (TBC) systems, with the aim of custom designing a TBC system to be both strain tolerant and have a low thermal conductivity. Methods of heat transfer within zirconia based ceramics are discussed, including the influence of coating microstructure and ceramic composition. It is shown the addition of dopant atoms (colouring) is effective in reducing â  phononâ  transport and that layered microstructures are effective in reducing â  photonâ  transport. Advanced processing, using EB-PVD coating methods has allowed both coloured and layered ceramic coatings to be produced. Measured thermal conductivities of 1.0 W mKâ  1 have been achieved using these methods, much lower than current commercial EB- PVD coatings at 1.5â