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José M. Marques,P.M. Carreira,J.E. Marques,H.I. Chaminé,P.E. Fonseca,F.A. Monteiro Santos,H.G.M. Eggenkamp,J. Teixeira 한국지질과학협의회 2010 Geosciences Journal Vol.14 No.4
The aim of this paper is to review the results of the assessment of low-temperature geothermal resources (issue temperatures between 41 and 77℃) that occur in the Portuguese mainland. For this purpose, a multidisciplinary approach, including geologic, tectonic, geochemical, geophysical and isotopic (2H, 18O, 13C, 3H and 14C) techniques, was applied in order to update local and/or regional conceptual circulation models. Three case studies of N-Portugal are presented and discussed. This paper describes different low-temperature geothermal waters presenting similar hydrogeological conceptual models but rather different geochemical signatures (e.g., HCO3–Na with pH 8, HCO3/Na/CO2-rich with pH 7 and HCO3–Na with pH 9, type waters). In fact, in the studied low-temperature geothermal systems, local/regional high altitude sites associated with highly fractured rocks play an important role in conducting the infiltrated meteoric waters towards the discharge zones near the Spas. The discharge zones are mainly related to the intersection of major regional fault lineaments (and conjugate structures), responsible for creating the mineral waters ascent. In some cases, geochemical and isotopic data point out to the existence of anthropogenic contamination of some geothermal spring waters related to the intense use of fertilizers in areas of widespread agricultural practices
Jorge Espinha Marques,José M. Marques,Helder I. Chaminé,Paula M. Carreira,Paulo E. Fonseca,Fernando A. Monteiro,Rui Moura,Javier Samper,Bruno Pisani,José Teixeira,José Martins Carvalho,Fernando Rocha 한국지질과학협의회 2013 Geosciences Journal Vol.17 No.3
Mountains are often considered as the world’s water towers. This paper presents a critical review on the research concerning the integrated assessment of groundwater resources of the mountain hydrogeologic system of Serra da Estrela Natural Park (central Portugal). The study area is the Zzere river basin upstream of Manteigas village located at the Serra da Estrela Mountain in Central Portugal. It provides the source of strategic water resources for the Portuguese mainland, including normal groundwaters, thermomineral waters and surface waters. An integrated approach has been used to formulate a conceptual model for this complex mountain hydrogeological system by integrating the geological, morphotectonic, hydroclimatic, unsaturated soil zone, hydrogeological, hydrogeophysical, hydrogeochemical and isotopic data. This model has been useful to: i) evaluate the water resources; ii) provide the basis for a sustainable management of water resources, iii) design measures for groundwater exploitation and contamination control; and iv) set up land-use policies.
Corrosion resistance assessment of nickel-titanium endodontic files with and without heat treatment
Costa Tatiana Dias,Silva Elison da Fonseca e,Caetano Paula Liparini,Campos Marcio José da Silva,Resende Leandro Marques,Machado André Guimarães,do Carmo Antônio Márcio Resende 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.1
Objectives: The aim of this study was to evaluate the corrosion resistance of heat-treated (Reciproc and WaveOne) and non-heat-treated (ProTaper and Mtwo) superelastic nickel-titanium endodontic files when immersed in a 5.25% sodium hypochlorite solution. Materials and Methods: Anodic polarization curves were obtained with potential sweeps that began at the open circuit potential or corrosion potential (Ecorr). The pitting potential (Epit) was identified on the anodic polarization curve as the potential at which a sudden increase in current was observed. The micromorphology of the 28 tested files was analyzed before and after the electrochemical assay using scanning electron microscope (SEM). The data were analyzed using 1-way analysis of variance with the post hoc Bonferroni test (for Ecorr) and the Student t-test for independent samples (for Epit). Results: The mean Ecorr values were 0.506 V for ProTaper, 0.348 V for Mtwo, 0.542 V for Reciproc, and 0.321 V for WaveOne files. Only WaveOne and Protaper files exhibited pitting corrosion, with Epit values of 0.879 V and 0.904 V, respectively. On the SEM images of the ProTaper and WaveOne files, cavities suggestive of pitting corrosion were detected. Conclusions: Signs of corrosion were observed in both heat-treated and non-heat-treated files. Of the evaluated files, WaveOne (a heat-treated file) and ProTaper (a non-heat-treated file) exhibited the lowest corrosion resistance.