Manufacturing cement-based materials and building products via extrusion: From laboratory to factory

Manufacturing is critical to the economies of the UK and many other countries in the rest of the world. However, manufacturing of cement-based materials and building products predominantly remains based on old batch processing such as casting and pressing technologies and this may limit the applications and performance of the materials and products formed. In this paper, research is reported on transforming manufacturing of precast cement-based materials and building products from in batches to continuous processes via extrusion. Techniques used for producing plastic products are transferred into manufacturing cement-based building products like flat and corrugated sheet tiles, down pipes, door/window frames, door panels, solid wall/facade panels, honeycomb wall/facade panels etc. at laboratory and factory scales. In combination with sustainable cementitious materials with low carbon and low energy as matrix, this enables sustainable building products with key characteristics required by the 21st century can be manufactured via extrusion. The cement-based building products extrusion technique has been successfully transferred to industry. For instance, fibre reinforced cement-based partition wall panels, with a honeycomb cross section as large as 600 mm wide and 90 mm high, have been produced by a continuous extrusion process in a precast concrete products factory in Hangzhou, China.European Commission Seventh Framework Programme, (grant agreement no. 262954) and from the Hong Kong Research Grants Council through grants 6091/00E, 6226/01E, 6273/03E and 6167/06

Rheology, fiber dispersion, and robust properties of Engineered Cementitious Composites

The capability of processing robust Engineered Cementitious Composites (ECC) materials with consistent mechanical properties is crucial for gaining acceptance of this new construction material in various structural applications. ECC's tensile strain-hardening behavior and magnitude of tensile strain capacity are closely associated with fiber dispersion uniformity, which determines the fiber bridging strength, complementary energy, critical flaw size and degree of multiple-crack saturation. This study investigates the correlation between the rheological parameters of ECC mortar before adding PVA fibers, dispersion of PVA fibers, and ECC composite tensile properties. The correlation between Marsh cone flow rate and plastic viscosity was established for ECC mortar, justifying the use of the Marsh cone as a simple rheology measurement and control method before fibers are added. An optimal range of Marsh cone flow rate was found that led to improved fiber dispersion uniformity and more consistent tensile strain capacity in the composite. When coupled with the micromechanics based ingredient-tailoring methodology, this rheological control approach serves as an effective ECC fresh property design guide for achieving robust ECC composite hardening properties.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94214/1/Mo-Rheology-2012.pd

Contributions of fluorescence techniques to understanding G protein-coupled receptor dimerisation

G protein-coupled receptors (GPCRs) are the largest class of eukaryotic cell-surface receptors and, over the last decade, it has become clear that they are capable of dimerisation. Whilst many biochemical and biophysical approaches have been used to study dimerisation, fluorescence techniques, including Förster resonance energy transfer and single molecule fluorescence, have been key players. Here we review recent contributions of fluorescence techniques to investigate GPCR dimers, including dimerisation in cell membranes and native tissues, the effect of ligand binding on dimerisation and the kinetics of dimer formation and dissociation. The challenges of studying multicomponent membrane protein systems have led to the development and refinement of many fluorescence assays, allowing the functional consequences of receptor dimerisation to be investigated and individual protein molecules to be imaged in the membranes of living cells. It is likely that the fluorescence techniques described here will be of use for investigating many other multicomponent membrane protein systems