Two Monterfortino helmets, recovered in the Mediterranean seabed, show unusual features with respect to the more common helmets of the same period and found in underwater environments. Hence, they ...were investigated by a multi-analytical approach, which allowed us to identify the compounds constituting the helmets and to make some considerations about their metallurgy, although all the metal was converted to degradation products. The helmets, originally made in bronze, have maintained their original shape because of copper sulphides formation. The observed differences in composition between the two helmets were attributed to the position modification, of one of them, into the seabed along centuries. For the first time, a microstructural investigation permits to reconstruct the history of the aging processes involved in the total oxidation of roman bronze helmet metal.
Ce:YAG nanostructures (Ce:YAG = Cerium in Yttrium Aluminium Garnet), easy to control and shape, have been prepared via templating approach using natural and synthetic materials (i.e. paper, cotton ...wool and glass wool) previously soaked with a gel-like metals precursor and then thermally treated to achieve the wished morphology. The final material, otherwise difficult to process, can be easily moulded, it is lightweight, portable and forms, at the nanoscale, homogeneous layers of interconnected but not agglomerated nanoparticles (15 ± 5 nm). Using the same synthetic route, called Urea-Glass-Route, but in absence of a template, extremely pure Ce:YAG nanoparticle (45 ± 5 nm) can be also prepared, highly crystalline and well-defined in size and shape. Both structural and optical properties of the final materials were investigated, showing high optical quality. The support allows the production of a multifunctional material with mouldable shape and potential lighting application for large structures combining the strength, chemical durability, fire resistance, and translucency of glass fibres. Last, but not least, the synthetic path also allows an easy scaling up of the process: the first, key step for practical application of nanosized rare-earth doped YAG on large scale.
This work follows a previous one dealing with the state of conservation study of the wooden part of the roman Acqualadroni rostrum soon after its finding in the seabed of Acqualadroni (Messina, ...Italy). The archaeological survey and recovery were particularly relevant since this artefact is one of the two rostrums, nowadays known, found together with its wooden part. Following the recovery, it was consolidated by immersion in a melamine-formaldehyde resin (Kauramin) aqueous solution for eight months at the “Centro di Restauro del Legno Bagnato” (Pisa, Italy). The present investigation is aimed to determine at microscopic scale the wood state of conservation and to highlight interactions of the consolidant with wood components, by using solid-state NMR spectroscopy ten years after the consolidation treatment. Sampling by coring was exceptionally authorized, and the wood core was divided into seven aliquots as a function of depth.
13
C cross-polarization magic angle spinning (
13
C{
1
H} CP-MAS NMR) spectra and variable contact time (VCT) experiments have been carried out to determine the cellulose crystallinity index, the lignin condensation degree and the holocellulose-lignin ratio. The interactions between the resin and the wood components were highlighted by T
1ρ
H relaxation times determination and two-dimensional
13
C–
1
H
correlation
(FSLG CP HETCOR) NMR experiments. Findings revealed specific interactions between the aromatic part of the resin and the lignin, as well as a network of hydrogen bonds involving all components of the system.
Graphic abstract
The conservation of ancient paintings sited in humid environments is an actual challenge for restorers, because it needs the knowledge of the materials the paintings are made up and of their ...interaction with a peculiar surrounding environment; thus, tailored procedures and strategies aimed at restoring and preserving paintings are necessary. Santa Margherita’s cave in Castellammare del Golfo (Trapani, Italy) is a natural cave, containing the remains of paintings, in a poor state of conservation, belonging to an ancient church dated back to the Middle Age. The present manuscript reports the monitoring of environmental conditions (i.e., temperature and humidity) in a full year, as well as a study on the materials constituting the stone support and the paintings together with a survey of the microbial community. The findings allow us to define the causes that mainly involve the degradation of the paintings. In detail, the degradation of the east and the west walls occurred differently because of the exposure to the sea aerosol, which influenced the salt composition, also contributing to diversifying the bacterial community. Some specific actions to plan the conservation and restoration of paintings and to preserve the site are suggested.
In this work, a multi‐scale approach with different analytical methods is applied to study the curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin. ...This monomer, thermally cured using 4,4′‐diaminodiphenilsulfone (DDS) as hardener, is analyzed after 10, 45, 90, and 120 min of reaction time at 180 °C to obtain information on samples with different cross‐linking densities. Samples are also characterized after extraction in acetone in order to obtain structural information on the insoluble parts. For this purpose, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), solid‐state nuclear magnetic resonance (ss‐NMR), and positron annihilation lifetime spectroscopy (PALS) are employed. The importance of this multi‐method approach lies in the possibility to obtain a more complete knowledge of the investigated system, overcoming the limits inherent to the use of a single technique, through the correlation among results obtained from different structural investigation methodologies.
The curing process and structural properties of a diglycidyl ether of bisphenol A are studied using a multi‐scale approach. The epoxy resin is analyzed at different cross‐linking densities by differential scanning calorimetry, dynamic mechanical thermal analysis, solid‐state NMR, and positron annihilation lifetime spectroscopy. The importance of this multi‐method methodology is the possibility of obtaining a more complete knowledge of the system, overcoming the limits inherent to the use of a single technique.
The aim of this paper was to establish the cause of sinking of an old wooden vessel by polycyclic aromatic hydrocarbon (PAH) analyses because wood combustion is a source of PAHs. In particular, the ...molecular PAH patterns generated by each source are like fingerprints and it is possible to determine the processes that generate PAHs by studying their distribution in wood samples. The relative abundance of high molecular weight PAHs, together with the PAH compound ratios and with total index (proposed by us) has demonstrated that samples owe their PAHs in wood archaeological material to a predominant single mode of origin, i.e. combustion processes, therefore we can say that the sinking of the vessel was caused by a fire.
•The knowledge of the cause of sinking of the archaeological materials might be of crucial interest for archaeologists, restorers, conservators etc.•The methodology used for the Scauri Ship may be extended to many archaeological objects.•The total index, proposed by us, permits to avoid the different responses of single indexes and identify the predominant sources of PAHs in a matrix.•The method uses negligible amounts of sample.
The iconographic heritage is one of the treasures of Byzantine art that have enriched the south of Italy, and Sicily in particular, since the early 16th century. In this work, the investigations of a ...Sicilian Icon of Greek-Byzantine origin, the
, is reported for the first time. The study was carried out using mainly non-invasive imaging techniques (photography in reflectance and grazing visible light, UV fluorescence, infrared reflectography, radiography, and computed tomography) and spectroscopic techniques (X-ray fluorescence and infrared spectroscopy). The identification of the constituent materials provides a decisive contribution to the correct historical and artistic placement of the Icon, a treasure of the Eastern European historical community in Sicily. Some hidden details have also been highlighted. Most importantly, the information obtained enables us to define its conservation state, the presence of foreign materials, and to direct its protection and restoration.
A Ce:YAG-poly(methyl methacrylate) composite was prepared using in situ polymerization by embedding the Ce:YAG nanopowder in a blend of methyl methacrylate (MMA) and 2-methacrylic acid (MAA) monomers ...and activating the photopolymerization using a radical initiator. The obtained nanocomposite was yellow and transparent. Its characterization was performed using transmission electron microscopy, small angle X-ray scattering, 13C cross-polarization magic-angle spinning nuclear magnetic resonance, and photoluminescence spectroscopy. Results showed that Ce:YAG nanoparticles are well dispersed in the polymeric matrix whose structure is organized in a lamellar shape. The luminescence properties of the nanocomposite do not show quenching or a significant spectral shift, indicating that the nanocomposite can be useful for advanced applications such as white LED construction.
Hydrophobic treatment is one of the most important interventions usually carried out for the conservation of stone artefacts and monuments. The study here reported aims to answer a general question ...about how two polymers confer different protective performance. Two fluorinated-based polymer formulates applied on samples of Cusa’s stone confer a different level of water repellence and water vapour permeability. The observed protection action is here explained on the basis of chemico-physical interactions. The distribution of the polymer in the pore network was investigated using scanning electron microscopy and X-ray microscopy. The interactions between the stone substrate and the protective agents were investigated by means of solid state NMR spectroscopy. The ss-NMR findings reveal no significant changes in the chemical neighbourhood of the observed nuclei of each protective agent when applied onto the stone surface and provide information on the changes in the organization and dynamics of the studied systems, as well as on the mobility of polymer chains. This allowed us to explain the different macroscopic behaviours provided by each protective agent to the stone substrate.
The “Trionfo della morte” is a detached fresco painting dated at the half of the XV century. Its history is strictly connected with the history of Palermo and it is considered a symbol of the late ...Gothic period. Some small areas of the fresco were analyzed using a combination of non-invasive techniques and hand-held instrumentations (multispectral imaging analysis, X-ray fluorescence (XRF), and IR spectroscopy). The characterization of the nature of pigments used in its realization and restoration works was performed and some indications about its conservation state were obtained. More interestingly, some hidden details were revealed on the mysterious painting. They constitute additional evidence of the preciousness of the fresco.
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