- Campus Diagonal Besòs
Av. Eduard Maristany, 10-14 08019 Barcelona
T. Pradell
Universitat Politecnica de Catalunya, Applied Physics, Faculty Member
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Lustre pottery unearthed at Mas Llorens constitutes one of most interesting collections of late 16 th and early 17 th centuries lustre pottery from Catalonia. The collection is formed by an unparalleled set of more than 200 complete... more
Lustre pottery unearthed at Mas Llorens constitutes one of most interesting collections of late 16 th and early 17 th centuries lustre pottery from Catalonia. The collection is formed by an unparalleled set of more than 200 complete dishes and bowls, which were buried in the same place and at the same time, thus becoming of paramount archaeological interest. Consequently, this set of lustre pottery has become of pivotal importance for the study of this type of ceramic not only because of the number and integrity of the pieces that were found, but also by its homogeneity. This multidisciplinary study has revealed the importance of this pottery in terms of economy, trade, and social status in Modern times Catalonia. The main purpose of this paper is to determine provenance and technology of production of lustre and other glazed wares from Mas Llorens. We present the results of the archaeometrical characterization of 21 ceramic sherds, recovered from the excavations of Mas Llorens. The...
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Recent excavations at the Fatimid and Zirid site of Sabra al-Mansuriya near Kairouan (Tunisia) provide the first evidence of lustreware production in medieval Ifriqiya, in the 10th–11th centuries AD. As the Fatimid dynasty moved from... more
Recent excavations at the Fatimid and Zirid site of Sabra al-Mansuriya near Kairouan (Tunisia) provide the first evidence of lustreware production in medieval Ifriqiya, in the 10th–11th centuries AD. As the Fatimid dynasty moved from Ifriqiya to Egypt to establish its capital in Fustat (Cairo), technological connections with the Egyptian lustreware could be expected. Tunisian lustreware may also be the link in the transmission of the technique towards Muslim Spain. It represents a new piece of the puzzle of understanding the diffusion of lustre technology from the East to the West of the Mediterranean. The composition and microstructure of the bodies and glazes, and the micro- and nano-structure of the lustre layer are compared in a preliminary approach to the technological relationships between Tunisian, Egyptian, and Spanish lustrewares.
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Precise microanalytical techniques are essential in many fields such as Cultural Heritage materials, showing complex layered microstructures containing a wide range of materials of diverse nature and hardness. Non-invasive sample... more
Precise microanalytical techniques are essential in many fields such as Cultural Heritage materials, showing complex layered microstructures containing a wide range of materials of diverse nature and hardness. Non-invasive sample manipulation and preparation is required to avoid, as far as possible, sample contamination which may strongly limit the materials identification. The method proposed consists in the application of thin gold or carbon protecting layers before embedding the samples in synthetic resin for microtoming. The validity and optimal procedure is checked for those materials most often found on the paintings surface: varnishes (natural resins and wax). An artwork sample is similarly prepared and analysed by Optical Microscopy (OM), Scanning Electron Microscopy (SEM/EDS), Micro Infrared Spectroscopy (µFTIR/ µSR-FTIR) and X-Ray diffraction (µSR-XRD) with synchrotron light.
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Peer ReviewedPostprint (published version
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A series of wall paintings dating from the Romanesque period to the 16th century were uncovered during restoration projects at the church of Santa Eulàlia of Unha in the Val d'Aran. This study centres on the use of... more
A series of wall paintings dating from the Romanesque period to the 16th century were uncovered during restoration projects at the church of Santa Eulàlia of Unha in the Val d'Aran. This study centres on the use of complementary spectroscopic techniques to ...
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Page 1. Role of Cinnabar in Luster Production Trinitat Pradell, Judit Molera, Ma`rius Vendrell, Josefina Pérez-Arantegui,§ Emmanuel Pantos,¶ Mark. Roberts,¶ and Marco DiMichiel Departament FEN, ESAB, Universitat ...
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ABSTRACT Luster is a decorative metallic film that was applied on the surface of medieval glazed pottery. It can be obtained via the low-temperature (∼650°C), controlled reduction of copper and silver compounds. In this paper, we show... more
ABSTRACT Luster is a decorative metallic film that was applied on the surface of medieval glazed pottery. It can be obtained via the low-temperature (∼650°C), controlled reduction of copper and silver compounds. In this paper, we show that luster is a thin layered film (200–500 nm thick) that contains metallic spherical nanocrystals dispersed in a silicon-rich matrix and has a metal-free outermost glassy layer that is 10–20 nm thick. Silver nanocrystals seem to be separated from those of copper, forming aggregates 5–100 μm in diameter. This composite structure exhibits optical properties that are dependent on both the particle size and the matrix. Luster is indeed the first reproducible nanostructured thin metallic film that was made by humans.
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Tin oxide (SnO2) particles that are a few hundred nanometers in size and are embedded in a lead glaze act as a white opacifier. The insolubility of SnO2 particles in a lead glaze is responsible for this microstructure. Although it is... more
Tin oxide (SnO2) particles that are a few hundred nanometers in size and are embedded in a lead glaze act as a white opacifier. The insolubility of SnO2 particles in a lead glaze is responsible for this microstructure. Although it is assumed that SnO2 particles do not react during the glaze formation, we demonstrate that the development of metastable phases prior to the fusion of the PbO-SiO2-SnO2 mixture allows the SnO2 particles to react and then recrystallize subsequent to the fusion of the mixture. The recrystallization of SnO2 occurs during heating and/or cooling until the temperature is sufficiently low and/or the tin supply is exhausted.
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The influence of different heat treatments on the nanocrystallization of Fe65Nb10B25 amorphous alloys obtained by melt spinning was investigated by differential scanning calorimetry (DSC), X ray diffraction (XRD), transmission Mössbauer... more
The influence of different heat treatments on the nanocrystallization of Fe65Nb10B25 amorphous alloys obtained by melt spinning was investigated by differential scanning calorimetry (DSC), X ray diffraction (XRD), transmission Mössbauer spectroscopy (TMS) and transmission electron microscopy (TEM). The microscopical analysis revealed that the heat treated samples consist of nanometer sized particles embedded in the amorphous matrix. The TMS analysis shows
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Non random nucleation processes are a subject of much interest in the study of first order phase transformations. However, the theory available to obtain the time evolution of the transformation for a nucleation and growth process, the... more
Non random nucleation processes are a subject of much interest in the study of first order phase transformations. However, the theory available to obtain the time evolution of the transformation for a nucleation and growth process, the well known Kolmogorov, Johnson-Mehl and Avrami kinetic equation (KJMA), is not accomplished if the nucleation process is nonrandom. Therefore, KJMA does not give an adequate description of the transformation kinetics.In the present paper, a non-random nucleation protocol resulting from a reduced nucleation rate due to the nearby presence of other growing grains is considered. Monte-Carlo simulations of such processes are performed, and the deviations from the Avrami kinetics observed are analyzed in detail.
ABSTRACT Yellow decorations in glasses have been produced since the beginning of the fourteenth century by incorporating metallic silver nanoparticles into the glass (from a few to some tens of nanometers). The optical response of the... more
ABSTRACT Yellow decorations in glasses have been produced since the beginning of the fourteenth century by incorporating metallic silver nanoparticles into the glass (from a few to some tens of nanometers). The optical response of the glass-particles composite is determined by the surface plasmon resonance absorption and scattering of the nanometric metallic particles. Generally, the same color is perceived in reflection and in transmission although dichroic effects are occasionally observed. As silver-stained glasses were designed to be observed in transmission, tuning the transmission color from yellow to red was of technological interest. The relationship between the color observed both in transmission and reflection and the composition and nanostructure of regular (yellow) and dichroic (yellow and red) silver stains from the Renaissance (late fifteenth and sixteenth century, respectively) is related to the presence of a layer (of about 10–20 μm thick) of metallic silver nanoparticles (from few to 100 nm in size). The correlation between the colors observed and the silver stain nanostructure is studied with particular emphasis on the origin of the dichroic behavior. The optical response is computed and compared to the experimental data. Differences in the synthesis parameters responsible for the colors and for the dichroic behavior of the silver stain glasses are proposed. This is essential for the replication of the glass pieces which are required as replacements in the restoration/conservation of the windows but is also of broader interest.
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ABSTRACT Lead antimonate was used to produce opaque yellow glasses from the beginnings of glass production in the Near East and Egypt around 1500 BC through into the Roman period. The composition and crystallographic structure of lead... more
ABSTRACT Lead antimonate was used to produce opaque yellow glasses from the beginnings of glass production in the Near East and Egypt around 1500 BC through into the Roman period. The composition and crystallographic structure of lead antimonate particles present in a small group of New Kingdom Egyptian and Roman glasses were investigated using analytical scanning electron microscopy and X-ray diffraction. The results showed that the particles were of the type Pb2Sb2O7 with a cubic structure and with the antimony partially replaced by iron and zinc in the case of the Egyptian glass, and by iron and tin in the case of the Roman glass. Synthesis in the laboratory of lead antimonate pigments, animes (i.e., lead–antimony–silica mixtures) and yellow glasses established that New Kingdom Egyptian and Roman yellow glasses could have been produced by stirring, respectively, lead antimonate pigment or anime, containing excess lead oxide, into a molten colourless glass. It is further shown that yellow lead antimonate particles are stable in glass up to operating temperatures in the range 900–1000 °C before converting to white calcium antimonate, and that their stability is enhanced by incorporating small amount of impurities such as iron, zinc and tin. The effect of different synthesis parameters and compositions on the colour of the glasses is investigated using UV–vis reflectance spectrometry.
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... L'analysedu tr?s volumineux mat?riel c?ramique recueilli dans la fouille des fours et des d?potoirs associ?s n'est pas sans poser quelques probl?mes (Leenhardt)... ... Si les fours des terrains 89 et 91 de Saint... more
... L'analysedu tr?s volumineux mat?riel c?ramique recueilli dans la fouille des fours et des d?potoirs associ?s n'est pas sans poser quelques probl?mes (Leenhardt)... ... Si les fours des terrains 89 et 91 de Saint Victor-des-Oules (c), Cabasse (d)et Goult (e) fin de la premi?re moiti? ...
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From antiquity, glazes have been one of the techniques used for decorating ceramics. Potters took advantage of the optical properties of these glazes to improve the quality of the object, especially to obtain an appearance or some... more
From antiquity, glazes have been one of the techniques used for decorating ceramics. Potters took advantage of the optical properties of these glazes to improve the quality of the object, especially to obtain an appearance or some characteristics that had commercial success. This is why it is important to know the reasons of the visual appearance of glazes. In this
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The production of polychrome decorated ceramics began in Ifriqiya in the 9th century under Aghlabid rule, with continuity during the 10th century under the Fatimids. These comprised finely painted brown and green designs with a... more
The production of polychrome decorated ceramics began in Ifriqiya in the 9th century under Aghlabid rule, with continuity during the 10th century under the Fatimids. These comprised finely painted brown and green designs with a characteristic yellow background (a transparent lead glaze containing iron oxide). This production was substituted in the 11th century by a polychrome production over a white tin opaque glaze. The hypothesis stating that tin glazes were introduced in Tunisia after the Fatimids took over Egypt has been recently proposed. However, polychrome ceramics with a white opaque background have been found in 10th century archaeological sites which might indicate otherwise. A ceramic assemblage found at the site of Bir Ftouha dating from the Fatimid-Zirid period which contains polychrome with both transparent yellow and white opaque backgrounds has been analysed. The white opaque glazes do not contain tin but were opacified by the addition of large quartz particles. This...
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Low-temperature bainite, obtained by the transformation of austenite at temperatures as low as 200ºC for times as large as several days, has been reported to have extraordinary mechanical properties including the highest reported hardness... more
Low-temperature bainite, obtained by the transformation of austenite at temperatures as low as 200ºC for times as large as several days, has been reported to have extraordinary mechanical properties including the highest reported hardness of any bainitic steel. The unusual properties are a consequence of the fine scale of the microstructure, which contains bainite plates with thickness in the range 20-40 nm. The microstructure also contains carbon-enriched retained austenite which contributes to the properties via a number of mechanisms. In this work, the microstructure of a high carbon bainitic steel with Si to avoid cementite precipitation and Co to accelerate the transformation has been studied using Mössbauer spectroscopy for a series of samples transformed isothermally at 200ºC for time periods of 26, 34 and 96 hours. The total austenite content is almost identical (~13 wt%) for these samples although the carbon concentrations of the phases differ as a function of transformation time. The austenite increases its carbon content from 5.4 atomic % after 26 h transformation to 6.3 at.% after 96 h, while the final bainitic phase retains about 2.2 at.% of C. These results are consistent with data obtained using atom probe tomography for samples transformed isothermally for 12 days.