The mobility of Na+, Li+, and K+ ions in thermally grown SiO2 films

Na+, Li+, and K+ ions have been implanted in thermally grown oxides (Tox =1000 °C) of metal‐oxide‐silicon structures. The mobilities of the Na+ and Li+ ions have been determined by means of the isothermal transient ionic current method in the temperature range 100–300 °C. The K+ mobility has been obtained by means of triangular voltage sweep measurements in the range 350–450 °C. The results show that the Na+ and the Li+ mobilities are not significantly different. The activation energies of the three measured mobilities are shown to agree with a quantitative model which has been developed by Anderson and Stuart [J. Am. Ceram. Soc. 37, 573 (1954)]

Future scenarios to inspire innovation

In recent years and accelerated by the economic and financial crisis, complex global issues have moved to the forefront of policy making. These grand challenges require policy makers to address a variety of interrelated issues, which are built upon yet uncoordinated and dispersed bodies of knowledge. Due to the social dynamics of innovation, new socio-technical subsystems are emerging, however there is lack of exploitation of innovative solutions. In this paper we argue that issues of how knowledge is represented can have a part in this lack of exploitation. For example, when drivers of change are not only multiple but also mutable, it is not sensible to extrapolate the future from data and relationships of the past. This paper investigates ways in which futures thinking can be used as a tool for inspiring actions and structures that address the grand challenges. By analysing several scenario cases, elements of good practice and principles on how to strengthen innovation systems through future scenarios are identified. This is needed because innovation itself needs to be oriented along more sustainable pathways enabling transformations of socio-technical systems

Nonlinear modal parameter identification in monopile-soil interaction by means of experimental data

Mechanical, Maritime and Materials EngineeringPrecision and Microsystems Engineering (PME

Geomechanical unloading behaviour of Boom clay for excavations

This thesis describes the geomechanical unloading behaviour of Boom clay for excavations. The Boom clay is of specific interest for the completion of the motorway ring around Antwerp. Many deep excavations in the Boom clay have to be performed, but the clay’s behaviour when unloaded is not fully understood to date. To gain better understanding of this behaviour a full scale trial excavation in Oosterweel, the west district of Antwerp, was performed. This resulted in unique field measurements on the Boom clay’s unloading behaviour. For the numerical modelling of the trial excavation two numerical models have been used: the Hardening Soil model with small strain stiffness (HSs) and the Generalised Hardening Soil (GHS) model. The numerical calculations have been performed with an axisymmetric approach, which was acceptable due to the octagonal shape of the trial excavation. It was found that the influence of small strain stiffness is important to model the displacements correctly. The long-term behaviour of the Boom clay remains a challenging point. It is recommended that laboratory oedometer tests are performed, lasting several months after the unloading steps. Additionally it is highly recommended to monitor the trial excavation in its current state for at least a year. This could provide crucial information on the long-term behaviour of the Boom clay.Civil Engineering and GeosciencesGeotechnical Engineerin