River metamorphosis and environmental change in the Macdonald Valley,New South Wales,since 1949

A significant metamorphosis of channel form occurred on the lower Macdonald River between 1949 and 1955; width and width-depth ratio increased and depth, sinuosity and weighted mean per cent silt-clay in the channel perimeter decreased. The channel has remained unstable since 1955, exhibiting frequent variations in bed elevation and a recent period of minor channel contraction followed by slight enlargement. Since 1946 there has been an increase in summer and annual rainfall and an abrupt, upward shift of the annual series flood frequency curve. As a result an increased proportion of the total sediment load of the river is now being transported as bed-material load. The change in sediment load is a result of greater stream competence and the consequent reworking of sandy sediment temporarily stored within the channel as benches. The observed channel changes are a quasi-adjustment to the increased flood and bed-material load discharges.     

PROVENIENCE STUDY OF MEDIEVAL BULGARIAN GLASSES BY NAA AND CLUSTER ANALYSIS

The neutron activation analysis results from 30 glass samples were subjected to cluster analysis. The reliable localization of part of the medieval glass finds from Preslav enabled the evaluation of the variety of the production of a medieval glass workshop (ninth-tenth century), allowing conclusions to be made about the technological level of glass-making in Bulgaria during the Middle Ages. The work proved that NAA followed by cluster analysis is a successful approach to finding the local and chronological features of the investigated glasses.     

SPECTROCHEMICAL ANALYSIS OF SOME MEDIAEV AL GLASS FRAGMENTS FROM CATALAN GOTHIC CHURCHES

AAS, FE and OES are each used in the analysis of thirteen samples of fragments of window glasses from three Catalan Gothic churches: Sta. Maria del Mar (Barcelona, Spain), Pedralbes Monastery (Barcelona, Spain) and Girona Cathedral (Spain). Two kinds of stained window glass are found. Special attention is paid to Co/Cu, Co/Ni and Cu/Ni ratios for blue glasses and Mn/Cu and Fe/Cu ratios for red glasses.