Micro- and nano-structural evolutions in white Portland cement/pulverized fuel ash cement pastes due to deionized-water leaching

Thin slices of white Portland cement-low calcium pulverized fuel ash (pfa) blended cement pastes containing 30 or 50% pfa were leached progressively in de-ionized water. The paste with 50% pfa was aged 13 years prior to leaching and those with 30% pfa were aged 1 and 13 years. Pastes were leached for up to 75 days and were characterized using thermal analysis, X-ray diffraction, analytical scanning and transmission electron microscopy, and solid-state nuclear magnetic resonance spectroscopy. Leaching affected the pastes in the following sequence: (i) crystals of Ca(OH)2 large enough to be resolved by backscattered electron imaging were removed completely prior to any effect on C-A-S-H; (ii) the Ca/Si ratio of C-A-S-H reduced from ≈1.4 to ≈1.0 whilst the aluminosilicate structure was unaffected; (iii) further reduction in the Ca/Si ratio of C-A-S-H was accompanied by lengthening of the aluminosilicate chains; (iv) the Ca/Si ratio of C-A-S-H reduced ultimately to ≈0.6

Measurement of H_20 absorption cross-sections for exploitation of GOME data

Research work carried out by Imperial College, London; UCL and the Rutherford Appleton LaboratoryAvailable from British Library Document Supply Centre-DSC:3425.929(4302) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

A Review of Cellulose Degradation and the Fate of Degradation Products Under Repository Conditions

The disposal of long-lived intermediate- and some low-level wastes (ILW/LLW) in vaults backfilled with cementitious material is one of a number of generic disposal concepts under consideration in the UK. The employment of a cementitious backfill results in the generation and persistence of a high pH (pH 12.5 to 10.5) environment within the disposal system. These conditions are favourable in terms of reducing the mobility of some radionuclides, however they also promote the chemical degradation of cellulosic materials present in some wastes. This alkaline chemical degradation of cellulose results in the generation of a range of soluble products some of which are able to complex radionuclides and potentially enhance their mobility (e.g. iso-saccharinic acid). This report reviews the current understanding regarding alkaline cellulose degradation and the associated impacts of radiolytic and microbial processes. Conceptual and mathematical models developed to describe alkaline cellulose degradation are also outlined and discussed. The nature and extent of alkaline cellulose degradation products are discussed together with their stability towards microbial and chemical degradation under repository and geosphere condition

A study of advanced techniques for monitoring atmospheric trace gases

Work carried out under a European Space Agency contractAvailable from British Library Document Supply Centre- DSC:3425.929(ESA-CR(P)--3433) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Ship/platform collision incident database (2001)

Includes bibliographical referencesAvailable from British Library Document Supply Centre- DSC:7761. 864(053) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo