Browsing by Issue Date, starting with "2013-02"
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- The use of diffuse reflectance mid-infrared spectroscopy for the prediction of the concentration of chemical elements estimated by X-ray fluorescence in agricultural and grazing European soilsPublication . Soriano-Disla, J. M.; Janik, L.; McLaughlin, M. J.; Forrester, S.; Kirby, J.; Reimann, Clemens; The EuroGeoSurveys GEMAS Project TeamThe aim of this study was to develop partial least-squares (PLS) regression models using diffuse reflectance Fourier transform mid-infrared (MIR) spectroscopy for the prediction of the concentration of elements in soil determined by X-ray fluorescence (XRF). A total of 4130 soils from the GEMAS European soil sampling program (geochemical mapping of agricultural soils and grazing land of Europe) were used for the development of models to predict concentrations of Al, As, Ba, Ca, Ce, Co, Cr, Cs, Cu, Fe, Ga, Hf, K, La, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, Sc, Si, Sr, Th, Ti, V, Y, Zn and Zr in soil using MIR spectroscopy. The results were compared with those obtained where MIR models were developed with the same soils but using the concentration of elements extracted with aqua regia (AR). The PLS models were cross-validated against the experimental log-transformed XRF values of all the elements. The calibration models were derived from a set of 1000 randomly selected calibration samples. The rest of the samples (3130) were used as an independent validation set. According to the residual predictive deviation (RPD), predictions were classified as follows: “Good quality”, Ca (2.9), Mg (2.5), Al (2.3), Fe (2.2), Ga (2.2), Si (2.1), Na (2.0); “Indicator quality”, V (1.9), Ni (1.9), Sc (1.9), K (1.8), Ti (1.8), Rb (1.8), Zn (1.7), Co (1.7), Zr (1.6), Cr (1.6), Sr (1.6), Y (1.6), Nb (1.6), Ba (1.5), Mn (1.5), As (1.5), Ce (1.5); “Poor quality”, Cs (1.4), Th (1.4), P (1.4), Cu (1.4), Pb (1.3), La (1.2), Hf (1.1). Good agreement was observed between the RPD values obtained for the elements analysed in this study and those from the AR study. Despite the different elemental concentrations determined by the XRF method compared to the AR method, MIR spectroscopy was still capable of predicting elemental concentrations.
- Geochemistry and provenance of the Carboniferous Baixo Alentejo Flysch Group, South Portuguese ZonePublication . Jorge, Raul CG Santos; Fernandes, Paulo; Rodrigues, Bruno; Pereira, Zélia; Oliveira, José Tomás
- Sources, background and enrichment of lead and other elements : Lower Guadiana RiverPublication . Batista, Maria Joao; de Oliveira, Daniel Pipa Soares; Abreu, Maria Manuela; Locutura, Juan; Shepherd, T. J.; Matos, João Xavier; Bel-Lan, A.; Martins, Luís Plácido
- Identification of tsunami deposits and their impact on coastal zones : a study case of the Boca do Rio estuary (Algarve, Portugal)Publication . Font, Eric; Pires, Cristina Veiga; Pozo, Manuel; Nave, Silvia; Costas, Susana; Ruiz Muñoz, Francisco; Abad, Manuel; Simões, Nuno; Duarte, Sílvia
- Hearing protection : selection factors and risks of excessive attenuationPublication . Matos, Maria Luísa Ferreira; Santos, Paula; Barbosa, FernandoCurrently, noise exposure in the occupational setting continues to be a problem in industrialized countries, not only because this is the most common occupational disease in these countries, but also because it is transversal to all activity sectors, including leisure activities. Exposure to high noise levels can affect the hearing system. For this reason, the legislation requires that the employer implements a set of measures to protect the exposed worker, and as last solution the use of individual hearing protection. However, what occurs in practice and in the majority of cases is the adoption of the use of hearing protection, at the expense of collective protective measures. Nevertheless, not always their selection is made of the most efficient manner. Excessive attenuation of the protectors, as well as the existence of sectors where impulsive noise is produced, are currently the main concerns of safety technicians.
- Adakitic-like magmatism in western Ossa-Morena Zone (Portugal) : geochemical and isotopic constraints of the Pavia plutonPublication . Lima, Selma M.; Neiva, A.M.R.; Ramos, João Farinha
- Rhenium incorporation in molybdenite : first results of a XANES studyPublication . Silva, Teresa; Figueiredo, M. Ondina; de Oliveira, Daniel Pipa Soares; Veiga, JP; Batista, Maria Joao
- Relationship productivity with noise patterns found in cycles of loading and transport in open quarriesPublication . Coelho, Ana; Matos, Maria Luísa Ferreira; Baptista, João Santos
- X-ray absorption spectroscopy at Re L3-edge applied to mine waste materials : a possible input to the sustainable recovery of rheniumPublication . Figueiredo, M. Ondina; Silva, Teresa; Veiga, JP; de Oliveira, Daniel Pipa Soares; Batista, Maria Joao