Eight rare-earth elements (REE), namely La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu, as well as other elements (Na, K, Sc, Cr, Fe, Co, Rb, Cs, Ba, Hf, Ta, and Th), have been determined in fifteen cretaceous clay samples of continental facies by instrumental neutron activation analysis. It was found that the REE contents are variable in absolute and relative values, but the means of these values are similar to those of European, shales. Analyses have also been made of the fractions <38 m and <2 m (clay-sized). The mineral contents of the clay-sized fraction were determined semi-quantitatively by X-ray diffraction. The results suggest the preferential presence of REE, Hf, and Th in fractions 2–38 m, which can be explained by the presence of apatite, monazite, and zircon. A correlation study of chemical and mineralogical data of the clay-sized fraction showed that kaolinite is correlated with REE, specially the lighter ones; illite with K, Rb, and Cs; and smectite with Na.
This paper is based on the information collected through a survey on technological innovation in a relatively large sample
of 1000 firms of the Brazilian Food Industry (hereafter BFI). 248 firms (24.8%) responded to the questionnaire and 77 (31.0%)
declared that they had introduced innovations in the period surveyed (1994–1996). This paper concentrates both on the different
characteristics related to food firms and innovative activity and on the nature of the innovations. Regarding the former we
have asked questions about firms' industrial sector, major activities, production stages, ownership, age, turnover, exports
effort, advertising, R&D and technological innovation effort, size (number of employees), external alliances, organization
of management functions (technological innovation policy, long term strategic plan, marketing research), and perceived barriers
to innovation. Regarding the nature of the innovations, questions included: institutional sources of knowledge of the innovations,
sources of innovations (external or internal), degree of protection of innovations (patents and other means), external collaboration,
novelty of innovations (radical or incremental), type of innovations (product, process or combined), newness of innovations
(to the world, to the country or to the firm), and impact of innovations on inputs (manpower, material, capital and energy).
The results of the research are presented in this paper in a descriptive way. Therefore, we have not carried out advanced
statistical analysis and we have not tried to establish cause-effect relationships among variables, but just links among them
and trends. From the analysis, we can claim that technological innovation is actually a very complex process within firms,
even though they are in a so called “low-tech” industry. Nevertheless, it is possible to identify outstanding factors linked
to this process both at industry level (some sectors are more innovative than others) and at firm level (the large firms tend
to be more innovative than small ones).
Three Canadian reference rocks, syenites SY-2 and SY-3, and gabbro MRG-1 have been analysed for Na, K, Sc, Cr, Fe, Co, Zn, As, Rb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta and Th, by instrumental neutron activation analysis. The results are reported and compared with usable values. In general the agreement is good.
Authors:M. Gouveia, M. Prudêncio, J. Barros, L. Morgado, and J. Cabral
Instrumental neutron activation analysis, atomic absorption spectrometry and conventional methods were used on five USGS Geochemical Exploration Reference Materials: GXR-1, 2, 3, 4 and 6. The concentrations of 35 elements are reported and compared with available literature values. In general the agreement is good.
Authors:A. Pacheco, M. Freitas, M. Baptista, M. Vasconcelos, and J. Cabral
This study deals with the influence of the exposure conditions on biological uptake, by looking into concentrations of Ni
and V in lichen thalli and tree bark after continuous and discontinuous field trials at littoral sites impacted by anthropogenic
emissions. Biomonitors were assessed by k0-INAA and AAS. Correlations at Sines are more apparent than at Viana or Lisboa. When data from all sites are pooled, V shows
correlations for practically every situation while Ni shows none, which may indicate a dissimilar uptake mechanism for each
element. At Sines, V/Ni ratios reach values that comply with emissions from oil-related industries.
Authors:M. Gouveia, M. Prudencio, I. Morgado, M. Magalhaes, and J. Cabral
Trace element data (Sc, Cr, Co, Hf, Ta and Th) are reported for a weathering profile of gabbroic rocks located near Serpa, Portugal. The results obtained for the whole rock samples showed that: (i) Co and Sc contents decrease upwards the profile. Co appears to be mobilized in the soil probably as soluble cation; (ii) Cr tends to remain in the profile; and (iii) Hf and Th concentrate in the upper horizons. Trace element distribution in different size fractions of the upper horizons revealed: (i) Sc, Cr and Co have a more uniform distribution than Hf, Ta and Th; (ii) Hf and Ta are concentrated in the intermediate fractions; and (iii) Th is concentrated in the finer fractions, probably due to incorporation in weathering resistant minerals, specially in the initial stages of weathering.
Authors:M. Gouveia, M. Prudencio, M. Freitas, E. Martinho, and J. Cabral
A numerical procedure is given to correct for the interference of U in the determination of the light rare earths, Zr, and Ru. The corresponding interference factors were calculated and their values compared with experimental results. The agreement is favourable in most cases.
Authors:M. Gouveia, M. Prudêncio, I. Morgado, and J. Cabral
Two reference rocks of the Geological Survey of Japan have been analyzed for Na, K, Sc, Cr, Fe, Co, Zn, Rb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Th and U, using instrumental neutron activation analysis. The results are reported and compared with consensus values proposed in the literature. In general, the agreement is good except for Cs.
Authors:M. Freitas, F. De Corte, M. Gouveia, M. Prudêncio, and J. Cabral
The Ree contents in lichens and plants determined by k0-standardized NAA with LEPD and HPGe are compared. We obtain similar values for Sm, Eu, Tb and Yb and better values for Ce and Nd by using LEPD Besides, LEPD allows the determination of Gd, Tm and Lu. The study of REE concentrations in the neighbourhood of two coal power stations show that: i) in the station under construction (C. T. Pego), the index of accumulation of each REE by the lichens and olive tree leaves is identical in two sampling loci where the soils have different REE concentration; and ii) in the station in operation (C. T. Sines), the REE contents in the soils is identical and the differences observed in the lichens and wild terrestrial plants are most probably due to the fly-ashes emmission from the station.
Authors:M. Freitas, A. Pacheco, I. Dionísio, S. Sarmento, M. Baptista, M. Vasconcelos, and J. Cabral
In a biomonitoring study aiming to find alternatives to lower epiphytes as air-quality monitors, lichens and tree bark were
exposed at different sites for discontinuous periods of 2 months and continuously. Native lichens were collected as well.
The contents for 22 elements were obtained by both instrumental neutron activation analysis (INAA) and inductively coupled
plasma mass spectrometry (ICP-MS). Quality control as asserted by analyzing ISE-921, NIST-1547 and TL-1 was good Losses of
As and Se by volatilization during sample digestion and neutron irradiation were evident, Ca contents by ICP-MS appeared underestimated
probably due to the formation of the insoluble fluoride. ICP-MS featured a better precision than INAA. Nonparametric statistics
were applied to the ICP-MS replicates, to those determined by INAA, and to compare the results of both techniques. High or
even excellent correlations were found between replicates in INAA, whereas, in ICP-MS, Cr and Ta were just fairly or not correlated.
As an overall comparison of the techniques, biased results were found for As, Ba, Ce, Cr, Cs, Hf, La, Sc, Se, Ta, and Zn,
unbiased results could be found for Ca, Co, Fe, K, Na, Rb, Sb, Sm, Tb, Th, and U.