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This article describes an experimental study on ash deposition during the co-firing of bituminous coal with pine sawdust and olive stones in a laboratory furnace. The main objective of this study was to relate the ash deposit rates with the type of biomass burned and its thermal percentage in the blend. The thermal percentage of biomass in the blend was varied between 10% and 50% for both sawdust and olive stones. For comparison purposes, tests have also been performed using only coal or only biomass. During the tests, deposits were collected with the aid of an air-cooled deposition probe placed far from the flame region, where the mean gas temperature was around 640 degrees C. A number of deposit samples were subsequently analyzed on a scanning electron microscope equipped with an energy dispersive X-ray detector. Results indicate that blending sawdust with coal decreases the deposition rate as compared with the firing of unblended coal due to both the sawdust low ash content and its low alkalis content. The co-firing of coal and sawdust yields deposits with high levels of silicon and aluminium which indicates the presence of ashes with high fusion temperature and, thus, with less capacity to adhere to the surfaces. In contrast, in the co-firing of coal with olive stones the deposition rate increases as compared with the firing of unblended coal and the deposits produced present high levels of potassium, which tend to increase their stickiness. (C)

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The purpose of the present work was to investigate whether the distribution of trace elements in human teeth of the Neolithic period in Portugal can reflect environmental conditions, dietary habits and uptake of some elements from the surrounding soil. An x‐ray fluorescence set‐up with microprobe capabilities, installed at the LURE synchrotron (France), was used for elemental analysis of teeth. The resolution of the synchrotron microprobe was 100 µm and the energy of the incident beam was 18 keV. The synchrotron microprobe concentration profiles for V, Mn, Fe, Cu, Zn, Sr and Pb in different regions of the tooth are discussed and correlated with the results obtained by cranio‐facial studies. The Mn and Fe concentrations were much higher in Neolithic teeth than in those of present humans. This may suggest uptake of both elements from the soil. Low concentration levels of Sr were found, which can be correlated with dietary habits. Moreover, the Pb concentration was very low in all the teeth analysed, in agreement with the low pollution levels of this element in this population. All samples were analysed without any chemical preparation. Copyright © 2004 John Wiley & Sons, Ltd.

This paper reports on the measurements of elemental profiles in teeth collected from two different populations, both living in isolated Portuguese islands of the Azores: S. Miguel and Terceira. Both populations are good producers of cattle, in spite of the proximity of the sea. The purpose of this work was to establish the influence of basic diet, based on meat, fish and dairy products, on teeth elemental content. Moreover, for a few elements, the differences between concentrations in corresponding regions of teeth was correlated with the proximity of the sea for the subjects of one of the islands. An x-ray fluorescence set-up with microprobe capabilities, installed at the LURE synchrotron (France), was used for elemental determination. The resolution of the synchrotron microprobe was 100 µm and the energy of the incident photons was 18 keV. Concentration profiles of Fe, Cu, Zn, Br, Sr and Pb in different parts of a tooth are discussed and correlated for both populations. The teeth collected for both populations show a similar behaviour with respect to the elemental distribution. Mn and Cu occur at low concentrations and they are almost constant in all the studied parts of teeth. The content of Sr is higher in the external enamel while the concentrations of Fe, Zn, Br and Pb increase in the inner part of the teeth. However, the contents of Br and Pb are different in the two populations. Higher levels of both elements were found in Terceira subjects. Moreover, the Sr concentration levels indicate that the diet of the studied individuals is richer in meat than in fish.

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