Millimetre-wave radar observations of glacier calving at Hansbreen (Svalbard) correlated with TLS, time-lapse camera images and seismic records

Publisher PD

Aggregation, ageing and transport properties of surface modified fumed silica dispersions

We have investigated the aggregation, ageing and transport properties of surface modified silica dispersions in DMSO by photon correlation spectroscopy and conductivity measurements. The surface modification introduces Li+-ions that dissociate in the dispersion creating a single Li+-ion conducting electrolyte. We show that the surface modification changes the aggregation and ageing properties of the material. There is a pronounced ageing observed for the modified silica dispersions. At high concentrations of fumed silica a gel state is found, which in the case of the surface modified silica is a very weak gel that can be rejuvenated by ultrasonic treatment. The key parameter controlling the aggregation in this system is hydrogen bonding and the surface modification results in a very low number of sites for hydrogen bonding. In addition there is a contribution from repulsive electrostatic interactions in the surface modified silica dispersions due to the highly charged surfaces of these particles. Furthermore, the Li+-ion diffusion, at low silica concentration, is three orders of magnitude faster than that of the silica particles and in the gel state the silica particles are immobile. We also find that the Li+-ion diffusion is virtually independent of the silica concentration in the dispersions.<br /

Artificial photosynthesis as a frontier technology for energy sustainability

Humanity is on the threshold of a technological revolution that will allow all human structures across the earth to undertake photosynthesis more efficiently than plants; making zero carbon fuels by using solar energy to split water (as a cheap and abundant source of hydrogen) or other products from reduced atmospheric carbon dioxide. The development and global deployment of such artificial photosynthesis (AP) technology addresses three of humanity's most urgent public policy challenges: to reduce anthropogenic carbon dioxide (CO2) emissions, to increase fuel security and to provide a sustainable global economy and ecosystem. Yet, despite the considerable research being undertaken in this field and the incipient thrust to commercialisation, AP remains largely unknown in energy and climate change public policy debates. Here we explore mechanisms for enhancing the policy and governance profile of this frontier technology for energy sustainability, even in the absence of a global project on artificial photosynthesis