X-ray powder diffraction investigations of Ruthenian-Byzantine frescoes from the royal Wawel Cathedral (Poland)

Abstract

Laboratory X-ray powder diffraction was applied to investigate the pigments used by medieval artists in Ruthenian-Byzantine frescoes in the royal Wawel Cathedral in Krakow (Poland). It was found that red fragments contained cinnabar (PDF 06-0256), yellow contained goethite (PDF 29-0713), and blue pieces contained azurite (PDF 02-0153). The green pigment, quite difficult to identify, was finally established as green earths—pigments commonly used in Byzantine wall paintings. Calcite (PDF 24-0027) was detected in all the samples. Small amounts of quartz (PDF 46-1045) in the plaster samples were also detected. The absence or presence of only minute amounts of quartz is a characteristic feature of the Ruthenian-Byzantine frescoes. Malachite was not detected in the green parts of the frescoes, in contrast to earlier investigations of wall paintings in Poland. Experimental details and the results obtained in this study are described and discussed.

Steam activation tuned porous structure and surface wetting behaviors of mesoporous biochars for corrosive oily wastewater treatments

“…The broad peak located at around 23° indicates the presence of amorphous carbon in these DG biochars 31 . The diffraction peaks located at 20.8°, 26.6°, 59.9°, and 68.1° correspond to the (100), (101), (211), and (203) crystal planes of SiO 2 (PDF 46–1045) 32,33 …”

“…31 The diffraction peaks located at 20.8°, 26.6°, 59.9°, and 68.1°correspond to the (100), ( 101), (211), and (203) crystal planes of SiO 2 (PDF 46-1045). 32,33 Aside from the increase of specific surface area, steam activation at 750 °C also enhances the hydrophilicity of DG biochars (750 °C). As shown in Figure 2 We further investigated the adsorption capacities of DG biochars (750 °C/750 °C) to dodecane, kerosene, cetane, and water, and the values obtained are 1.88, 2.68, 2.45, and 3.07 g/g, respectively, as shown in Figure 3(a).…”

Non‐invasive surface analysis of ancient bronze arrowheads with scanning electron microscopy and X‐ray powder diffractometry

“…Due to the unique nature of historical artifacts, the crucial role in physicochemical studies of antiquities is played by nondestructive techniques as microscopy, [1][2][3][4] X-ray diffraction (XRD), 2,5 and various spectroscopic techniques: X-ray fluorescence spectroscopy (XRF), 6,7 X-ray photoelectron spectroscopy (XPS), [2][3][4]8 infrared spectroscopy (IR), 9,10 and Raman spectroscopy (RS) 11,12 to mention the most widely applied in surface analysis. Though the samples measured with these techniques can be used in other ones, only a handful can be applied without any invasive sampling or custom designed instruments.…”