The inventorying of building stone performance-in-use to assess susceptibility to decay

The Natural Stone Database for Northern Ireland was constructed to address the paucity of information available to stone conservation practitioners within the region. Almost 2000 listed buildings and monuments were surveyed over three years to produce an interactive GIS database. This contained information on stone sources, together with details of stone condition and decay processes. This paper uses elements of this GIS to investigate stone decay patterns across Northern Ireland. The results demonstrate that as the level of stone decay increases, so does the proportion of buildings with sandstone as the primary stone type. It appears that a
higher open porosity level combined with Northern Ireland’s wetter climate and maritime location leads to rapid wetting and drying cycles within sandstones. This is coupled with the ingress and crystallisation of marine and other salts within stone pores leading to considerably
higher rates of decay than for any other stone type.

Autonomous COLREGs Compliant Ship Navigation, Using BridgeSimulators and an Unmanned Vessel

This paper presents an approach to COLREGs compliant ship navigation. A system architecture is proposed, which will be implemented and tested on two platforms: networked bridge simulators and at sea trials using an autonomous unmanned surface vessel. Attention is paid to collision avoidance software and its risk mitigation.