Ultrasonic Evaluation of Interfacial Properties in Adhesive Joints: Evaluation of Environmental Degradation

It is known that failure of adhesive joints can occur either in the bulk region of an adhesive layer (cohesive mode) or along an interface between the adhesive and an adherent (interfacial or adhesion mode). Properly manufactured adhesive joints fail in the cohesive mode, while after environmental degradation the failure mode becomes predominantly interfacial. Therefore we conclude that humid environments affect mostly the interfacial region of a joint. This indicates the importance of non-destructive assessment of interface properties. While methods of cohesive property evaluation have progressed significantly, much more effort is required to develop interface evaluation methods. A development of this type is undertaken in this work

A struggle towards an alternative governance to an executive-led government: a case study of harbour-front planning in Hong Kong

AESOP 21st congress - Planning for the Risk Society, organised by the Association of European Schools of Planning (AESOP)

Vortex avalanches in superconductors visualized by Magneto-Optical Imaging

The vortex diffusion in Type II superconductors is the dominant dissipative mechanism both in transport and in magnetization properties. The strong nonlinear relation between the current density and the electric field, along with nonlocal interactions, determines the complex behavior of the vortex matter, which also includes "catastrophic" phenomena such as vortex avalanches. Here, I present a brief review of the experimental studies devoted to these unstable vortex patterns, starting from the historical findings up to recent works, and focusing on the analysis of the vortex avalanches by means of Magneto-Optical Imaging. This technique enables the observation of the magnetic field distribution in real time, on the whole surface of the superconductor, with microscopic resolution. Hence, both dynamics and morphology of the vortex avalanches are reported in detail, along with theoretical efforts for understanding and for modeling this complex phenomenon. It turns out that vortex avalanches are ubiquitously occurring in superconductors, if certain conditions are satisfied: in particular, temperature, applied magnetic field, and applied field rate are of paramount importance for observing/avoiding these phenomena. It is worthy to note that, together with the interest in fundamental behavior of the vortex matter, this study is instrumental for assessing the limits of usage of superconductors in power applications