In this work, the pigments and ground layers of the Saint John the Evangelist painting were analyzed using the techniques of computed radiography, X-ray fluorescence (XRF), and micro-Raman spectroscopy. The painting was purchased by a collector at auction as a 19th-century work of art of unknown authorship. XRF analyzes were performed with a voltage of 40 kV, current of 50 µA, and acquisition time of 60 s. Micro-Raman spectroscopy measurements of a black fragment sample were performed with the Thermo Scientific – DXR2 Raman microscope equipment. The sample was excited by the adjusted 785 nm laser source with a power of 4 mW, focused on the sample using a 100x objective. It was possible to characterize the pigments used in the painting of São João Evangelista as Lead White, Vermilion, Carbon Black, and Ocher. No areas of repainting and modern pigments were identified that could suggest any type of intervention.
Atmospheric particulate matter (PM) is considered to be a set of pollutants suspended in the air, from industrial processes, motor vehicle exhaust, resuspended street dust, biomass burning, and others. Among the toxic chemical compounds, PM is considered contaminants of great importance for researchers, as they offer harmful effects to humans, fauna and flora. Moreover, exposure to PM can cause the development and/or worsening of diseases, mainly respiratory and cardiovascular. The aim of the present study was to evaluate the metals concentration in total suspended particulate matter in the air through total reflection x‐ray fluorescence technique (TXRF). The samples were collected from random points in five neighborhoods in the Metropolitan Region of the state of Rio de Janeiro/Brazil. TXRF measurements were performed using the benchtop TXRF spectrometer S2 PICOFOX. The results showed that the proposed methodology was able to detect the elements Cr, Fe, Ni, Cu, and Zn, in concentrations ranging from 2.0 to 200 ng.m−3. It can be concluded that the study methodology for determining the metal concentrations in air samples is an efficient and low‐cost solution for studying environmental pollution.
In this study, the characterization of the “Santa Luzia” statue was carried out through three non‐destructive X‐ray techniques: X‐ray Fluorescence (XRF), Digital Radiography (DR), and Computed Tomography (CT). The wooden statue dates from the 18th century. It was carved in Portugal and is currently located at the Santa Luzia church—one of the oldest churches built in Rio de Janeiro. The portable XRF system used in this study is composed of an Ag target X‐ray tube and an silicon drift detector detector with energy resolution of 122 eV at 5.9 keV. Several spectra were obtained in different regions of the statue. For the DR and CT evaluations, a portable 120 kV X‐ray tube and a 410 × 410 mm a‐Si flat panel detector with a pixel size of 200 μm were used. Individual radiographs of the parts of the statue were acquired and merged into a single image, in order to show its complete radiography. Finally, the CT images of the head of the statue were taken in angular steps of 2 degrees and, after the reconstruction process, the data were analyzed by means of appropriate software. The elements found in the XRF analysis suggest the presence of the pigments lead white, red lead, zinc white, titanium white, vermilion and emerald green. All of them are in accordance with the pigments used by the artists during the statue's historical period. The 3 exceptions were the zinc white and titanium white pigments, which may be an evidence of modern interventions, and the emerald green pigment, which appears to be a repainting of the green region. The radiographic images showed the manufacturing process of the statue, as well as its structural condition. The assembling of wooden blocks, the presence and type of nails and spikes, and regions of different densities were found in the analysis. In the statue's head, the joining of the face with the main part of the statue is clearly visible, and also the hollow glass eye. The CT analysis was able to better detail this section as a spherical cavity in the central part of the head, as well as the presence of a high‐density fragment inside the hole for the fixation of the aureole. The type of glass eye was identified as blown‐glass eye, which is commonly used in devotional statues.
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