Abstract: The main results and conclusions are presented of a round robin study of silicon oxide on silicon reference samples for ellipsometry. The oxide films with nominal thicknesses of 10, 50 and 120 nm are grown by thermal oxidation. The oxide film thicknesses have been determined by single wavelength ellipsometry (SWE), by spectroscopic ellipsometry (SE) and by cross-sectional conventional and high-resolution transmission electron microscopy (TEM and HREM) in different laboratories. The main conclusions are that special precautions have to be taken in order to use TEM as a reliable thickness measurement technique; that single wavelength ellipsometry can be used with great accuracy and reproducibility for the 50 and 120 nm film thicknesses but that it shows some inherent problems for the 10 nm films; and that spectroscopic ellipsometry showed for all film thicknesses an accuracy and reproducibility which is clearly superior to that of SWE.

Abstract: The integration of the nonlinear least squares X-ray spectrum evaluation progam AXIL. into a mu-PIXE and a mu-XRF setup is discussed. The use of the software when procesing data sets derived from biological and geological samples is described.

Abstract: Spark source mass spectrometric analyses of doped carbon samples were performed at different pulse lengths, pulse frequencies and breakdown voltages. The pulse length and pulse frequencies had no influence on the analysis. The relation between breakdown voltage, spark gap and sample matrix was determined. With increasing breakdown voltage, the abundance of the multiply charged ions was found to decrease, whereas the abundance of the cluster ions increased. The breakdown voltage was also found to affect the absolute and relative intensities of different elements in different manners. Interpretation of these results led to some new considerations on the phenomena in a spark discharge.

Abstract: Homogenised and quenched Ni65Al35 samples were heated and studied in situ in a CM20 electron microscope up to 900 degrees C. The Ni5Al3 phase first forming around 550 degrees C in the quenched L1(0) microtwinned martensite starts to decompose around 800 degrees C yielding B2 precipitates in a twinned L1(2) matrix. The latter twinning is a remainder of the microtwinning in the original room temperature martensite. Also the crystallographic relations between precipitates and matrix can be traced back to the original formation of twinned martensite plates within the austenite. Some aspects of the dynamics of the process are discussed on the basis of snap shots and video recordings.

Abstract: In November 1984 in Makasar and the Flores Basin water samples were collected (T, S, dissolved O2, total CO2), bottom samples (sediment composition) and suspended matter (particle composition, particle size). A sediment trap was moored in the Flores Basin at 4600 m depth for nearly four months, covering the dry season. In the Flores Basin there are indications for bottom flow resuspending bottom material or preventing suspended material from settling; in Makasar Strait there is probably inflow of deep water both from the south and from the north, resulting in a very slow bottom water flor. Bottom deposits in Makasar Strait and the Flores Basin are predominantly terrigenous, with an admixture of organic carbonate and silica (mostly coccoliths). Volcanic material is primarily present near to the volcanoes in the south and reaches the deeper basins by slumping. In the suspended matter no volcanic particles and little planktonic material were found, although the latter form 10 to 15% of the top sediment and of the material deposited in the sediment trap. In suspension particles with a large concentration of tin (Sn) were found associated mainly with iron. They probably come from northern Kalimantan or northern Sulawesi. Suspended matter concentrations were mainly less than 0.5 mg·dm−3, only off the Mahakam river mouth were concentrations higher than 1 mg·dm−3. Particle size was erratic because of the variable composition of the coarser particles in suspension. Organic matter concentrations in suspension (in mg·dm−3) roughly follow the distribution of total suspended matter but organic content (in %) of the suspended matter does not show any trends. All organic matter in suspension is of marine origin except in the Mahakam river and estuary. Deposition rates, as estimated from the sediment trap results, are 150 mg·cm−2·a−1 for the total sediment, 26 mg·cm−2·a−1 for carbonate and 13 mg·cm−2·a−1 for organic matter. Flocs and fibres in suspension were only found in and below the Mahakam river plume that reaches ca 400 km from the river mouth to the southeast, and in surface waters associated with plankton (diatoms). The formation of these flocs (broken-up macroflocs or marine snow) is primarily related to particle concentration, turbulence, and the presence of organisms that produce sticky material or glue particles together.

Abstract: Air particulate samples were collected at Chapiquiña near Arica (Chile) with a six-stage cascade impactor for about 17-day periods during a 31 month interval. Sixteen elements were determined by energy dispersive X-ray fluorescence analysis, and the elemental concentrations were subjected to principal factor analysis. The variability with time of the coarse particles was described by two factors both related to soil dispersion, whereas the fine particle variations could be explained by a third factor related to marine influence. Enrichment factors were compared with those obtained in other remote continental areas, in particular those of air particulate matter sampled at Chacaltaya, Bolivia. Results point to a negligible anthropogenic influence.

Abstract: In air particulate matter, sampled at a suburban site near the city of Antwerp, Belgium, more than 1500 individual Pb-containing aerosol particles with projected diameters between 0.2 and 15 μm were analyzed by automated electron probe X-ray micro analysis (EPXMA) for 26 elements and morphological features. Laser microprobe mass analysis (LAMMA) was used to detect elements with Z < 11, particularly ammonium compounds. The Pb-containing particles were classified into five main classes: Pb-sulfates, Pb-halides, soil related Pb, Pb associated with medium atomic number elements and Pb associated with high atomic number elements. Each class was divided into several distinct particle types, of which the abundance (in number and mass %), the mean projected particle diameter, and the chemical composition were determined. Auto exhaust products are responsible for Pb-sulfates and Pb-halides, making up respectively 66.7 and 27.8% by mass of the Pb-containing particles. Ammonium sulfate coatings were found to be present on nearly all Pb particles. The observations were correlated with daily concentrations of Pb and Br, obtained by particle induced X-ray emission analysis (PIXE).

Abstract: Energy-dispersive X-ray fluorescence was used for the analysis of hair samples from three different age groups of the Sudanese population. Hair samples were digested in a mixture of nitric and perchloric acids and the metals were then precipitated with ammonium pyrrolidine dithiocarbamate. The variations of the Fe, Cu, Zn and Pb content of hair with age were investigated. The averages of the elemental concentrations in each age group were compared with the other age groups and with literature values. The correlation of each pair of elements in the hair samples was also investigated.

Abstract: Different trace- and microanalytical techniques were used in an extensive study to elucidate the chemical deterioration process of the sandy-limestone St Rombouts Cathedral in Mechelen, Belgium. Samples of stones, mortar joints, slates, atmospheric aerosols and gases, total and wet deposition, and water that had run down the cathedral walls, were all thoroughly characterized. At the east side, usually not exposed to precipitation, a 3001000-μm thick outer crust of microcrystalline gypsum was observed, while at the west side, this surface layer was mostly eroded away due to precipitation. At the north and south sides, the crust contains varying amounts of gypsum and calcite. The gypsum is mostly present in a bar-shaped morphology and carbonaceous fly-ash particles were rarely found in the weathering crust. Local stone characteristics seem to be extremely important in relation to the gypsum content of the crust; black samples always have a much higher sulphate content than the corresponding white samples, irrespective of the predominant direction of orientation. The relative contribution of nitrogen- and chlorine-containing pollutants to the total decay process is much smaller than that of sulphur-containing pollutants. Deposition samples collected at the site of the cathedral mostly had a pH of > 5.6, due to the neutralization of the rainwater by alkaline atmospheric constituents. Runoff water and washdown water were enriched in all ions, especially Ca2+ and SO42−, indicating that, indeed, gypsum is the most important weathering product. The suspension in deposition samples and black-well leaching water was highly enriched in silicon-containing particles, while runoff water and white-wall leaching water contained a predominant calcium-rich suspension.