IoM3 — Young Persons Lecture Competition — 2009
Wednesday, February 11th, 2009 at 19:30
Carbonation of lime: a micro-structural study — Graham Griffiths, University of Bristol
The classical civilizations of Greece and Rome used lime to build structures otherwise impossible without a binder. Limestone was quarried, slaked and set. This setting was made possible through a reaction with airborne carbon dioxide, to form crystals which glued the masonry together. The slaked lime itself is made of 'calcium-hydroxide' and it is on the surface of these particles that the reaction occurs. This fixes carbon-dioxide in the form of 'calcium-carbonate', effectively artificial limestone. Removal of carbon dioxide from the environment in this way is of great contemporary interest. In the age of carbon-footprints and global warming, a means to permanently take the gas from the environment is of great use.
Effect of fabrication history on creep damage in type 316H stainless steel weldments — Bo Chen, University of Bristol
AISI Type 316H austenitic stainless steels were used in the fabrication of a wide range of components in Nuclear Electric Advanced Gas Cooled (AGR) Power Stations. To date, reheat cracking of as-welded stainless steel welds has been found at Heysham 1, Hartlepool, Dungeness B and other sites. The threat of reheat cracking at Heysham 1 and Dungeness B has resulted in major engineering plant modifications during outages in 1995/1996. The present study is motivated by a need to understand the manufacturing-introduced factors contributing to subsequent creep damage, especially reheat cracking in austenitic stainless steels. In this lecture, an introduction of the reheat cracking phenomenon will be given firstly. To address the threat of reheat cracking, experimental work is ongoing at the University of Bristol which is aimed at improving the current understanding of the reheat cracking mechanism. Finally, a concise summary and recommended future work will be delivered.