Search results for "medium"
showing 10 items of 3746 documents
Non-Invasive Investigation of Pigments of Wall Painting in S. Maria Delle Palate di Tusa (Messina, Italy)
2019
The characterization of materials used in the archaeological field needs an experimental approach in order to avoid the destruction or perturbation of artworks. In order to afford this purpose, a multi-analytical spectroscopic approach is regularly used. We combined non-invasive analysis by using handheld spectroscopic instrumentations (mainly XRF and Raman spectrometers) in order to characterize the wall painting preserved in the church of S. Maria delle Palate at Halaesa Arconidea archeological site (Tusa, Messina, Italy). The aim of the work is the characterization of the nature of pigments used for the realization of the wall painting. The wall painting, probably representing St. Franci…
From Historical Silk Fabrics to Their Interactive Virtual Representation and 3D Printing
2020
The documentation, dissemination, and enhancement of Cultural Heritage is of great relevance. To that end, technological tools and interactive solutions (e.g., 3D models) have become increasingly popular. Historical silk fabrics are nearly flat objects, very fragile and with complex internal geometries, related to different weaving techniques and types of yarns. These characteristics make it difficult to properly document them, at the yarn level, with current technologies. In this paper, we bring a new methodology to virtually represent such heritage and produce 3D printouts, also making it highly interactive through the tool Virtual Loom. Our work involves sustainability from different per…
Diagnostics for the knowledge: the case of the tower of Palazzo Termine Pietragliata in Palermo (Italy)
2015
[EN] Developing a methodological approach is crucial to assess the state of conservation of a monument, starting from the overall analysis, progressively moving from small to medium scale and reaching the grand scale at the end. Considering the territory, causes are investigated in order to understand the propensities, as well as considering a single monument, evidences are carefully read to assess the overall conditions, that will be lately detailed by the analysis on materials and their degradation. The object of this study is the tower of the Palazzo Pietragliata in Palermo, one of the most important examples of the late Gothic civil architecture in Sicily. The Palace, built in 1473 by P…
High resolution Fourier transform infrared spectroscopy and analysis of the ν 6 band of jet-cooled Mo(CO) 6
2000
Abstract Rovibrational FTIR spectra of Mo(CO) 6 have been recorded in supersonic argon expansions at 0.004 cm −1 resolution. Rotational constants have been determined for the ν 6 fundamental band of Mo( 12 CO) 6 and for the parallel band of the symmetric top isotopomer Mo( 13 CO)( 12 CO) 5 . From these results, a precise estimate of the Coriolis parameter for the ν 6 band of the main isotopomer Mo( 12 CO) 6 is derived, necessary for the analysis of the ν 6 spectrum. The observation of an octahedral splitting clearly resolved for the highest J-lines in the R branch prompted the use of a specific treatment based on the tensorial formalism developed by J.P. Champion, M. Loete, G. Pierre (Spher…
Broadband dielectric spectroscopy of 0.4PMN-0.3PSN-0.3PZN ceramics
2007
In this paper, results of the broadband dielectric spectroscopy of 0.4PbMg1/3Nb2/3O3-0.3PbZn1/3Nb2/3O3-0.3PbSc1/2Nb1/2O3(0.4PMN-0.3PZN-0.3PSN) are presented. Dielectric spectra of these solutions were investigated in a broad frequency range from 20 Hz to 100 GHz. Very strong and broad dielectric relaxation was analyzed in terms of distribution of relaxations times, using Tichonov regularization method. It revealed slowing down of the longest relaxation and the mean relaxation times in the agreement with the Vogel-Fulcher law and the Arrhenius law, respectively.
The effects of Pr3+ doping on the dielectric and photoluminescence properties of BaTi0.9(Yb0.5Nb0.5)0.1O3 ceramic
2019
Abstract The praseodymium Pr3+ doped BaTi0.9(Yb0.5Nb0.5)0.1O3 (BTYN01) ceramic, under low concentration (0.1%), was prepared by a conventional ceramic fabrication technique and its phase structure, microstructure, dielectric, vibrational and photoluminescence (PL) properties was studied. Both X-ray diffraction (XRD) and Raman studies confirmed the incorporation of Pr3+ into A-site lattice of BTYN01. The structure of Ba0.9985Pr0.001□0.0005Ti0.9(Yb0.5Nb0.5)0.1O3 (BTYN01-Pr) shows the coexistence of Pm 3 ¯ m -cubic symmetry (∼10%) and P4mm-tetragonal symmetry (∼90%) at room temperature. The dielectric study reveals that the maximum of the dielectric constant of BTYN01-Pr occurred at 283 K. The…
Fragmentation of polycarbonate macroinitiators in solution and in the bulk state
1990
The diphenylethane initiator 3,4-diethyl-3,4-(p-methoxyphenyl)-hexane (T–OCH3) was synthesized. By cocondensation of bisphenol A or C and the bisphenol derivative (“T”) of T–OCH3 with phosgene, polycarbonate macroinitiators PC(TxA1-x) and PC(TxC1-x) with different compositions x were made. The thermal fragmentation of T–OCH3 and the copolycarbonates was investigated with and without a radical scavenger both in solution and in the bulk state. The primary dissociation of T–OCH3 is a monomolecular Arrhenius process with a characteristic temperature of T* (τ = 1h) = 140°C (τ: average life time of the intact molecule). When the radicals are not intercepted, the dissociation is excessively revert…
Scheelite-Bearing Metalliferous Sequences of the Peloritani Mountains, Northeastern Sicily (with some Remarks on Tungsten Metallogenesis in the Calab…
1988
The Peloritani Mountains (Northeastern Sicily) are part of a segment of the Hercynian chain recognized in the Calabrian-Peloritan Arc, geotectonically defined by a pre-Hercynian crystalline basement (Aspromonte Nappe + Mandanici Unit) overthrust and overturned on its Paleozoic (Cambro-Ordovician up to Devonian Carboniferous) volcanosedimentary cover. Tungsten (scheelite) and associated polymetallic stratabound ores, more or less intensely affected by the pre-Hercynian and Hercynian tectonometamorphic events, are confined to the pre-Hercynian basement. In particular, the most significant scheelite-tourmaline (arsenopyrite) and scheelite-carbonate-quartz (albite) mineralizations could be cons…
Mineral control of arsenic content in thermal waters from volcano-hosted hydrothermal systems: Insights from island of Ischia and Phlegrean Fields (C…
2006
This paper documents arsenic concentrations in 157 groundwater samples from the island of Ischia and the Phlegrean Fields, two of the most active volcano-hosted hydrothermal systems from the Campanian Volcanic Province (Southern Italy), in an attempt to identify the environmental conditions and mineral-solution reactions governing arsenic aqueous cycling. On Ischia and in the Phlegrean Fields, groundwaters range in composition from NaCl brines, which we interpret as the surface discharge of deep reservoir fluids, to shallow-depth circulating fluids, the latter ranging from acid-sulphate steam-heated to hypothermal, cold, bicarbonate groundwaters. Arsenic concentrations range from 1.6 to 690…
H-2, H-3(+) and the age of molecular clouds and prestellar cores
2012
Measuring the age of molecular clouds and prestellar cores is a difficult task that has not yet been successfully accomplished although the information is of paramount importance to help in understanding and discriminating between different formation scenarios. Most chemical clocks suffer from unknown initial conditions and are therefore difficult to use. We propose a new approach based on a subset of deuterium chemistry that takes place in the gas phase and for which initial conditions are relatively well known. It relies primarily on the conversion of H 3 + into H 2D + to initiate deuterium enrichment of the molecular gas. This conversion is controlled by the ortho/para ratio of H2 that i…