Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes

Abstract The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of…

Degradation of stone materials in the archaeological context of the Greek-Roman Theatre in Taormina (Sicily, Italy)

In the present work results on the degradation phenomena of stone materials in the Ancient Theatre of Taormina, one of the most important Greek–Roman monuments of Sicily, are reported. Artificial stone materials in different conservation conditions were investigated. Samples of salt efflorescences from brick walls and degraded setting mortars were taken from the open gallery in “summa cavea”. The chemical, physical and structural characterization was performed by means of X-Ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF), both in situ and ex situ. Results showed that the deterioration of stone materials is due to the aggressive action of the enviro…

Studio integrato di rocce sedimentarie da cave siciliane di interesse storico-artistico

Radiation effects in nitride read-only memories

Abstract We report on the influence of different types of radiation on the nitride read-only memories (NROM®). The memory cells were irradiated by light ions (Boron), X-rays and γ-rays. Memory transistor parameters, such as threshold voltage and subthreshold drain leakage were studied as a function of the accumulated radiation dose and compared to the as-programmed (-erased) devices parameters. Their time evolution was registered in the range from few hours up to 5 months after the irradiation. The NROM® cells showed good radiation robustness up to high accumulated doses. Sufficient program margin (difference of threshold voltage in the programmed state and the read-out voltage level) remai…

Degradation study of XVIII century graffiti on the walls of Chiaramonte Palace (Palermo, Italy)

A systematic investigation of the original materials and the degradation phenomena induced by soluble salts on the wall matrix and on the graffiti of the Inquisition jails of Chiaramonte Palace in Palermo (Italy) was carried out. Built in the XIV century, Chiaramonte Palace was used as Inquisition court during the XV–XVI centuries. The ancient graffiti, recently discovered, represent a unique historical witness of the prisoners that lived during that terrible period. In order to study the nature, the amount and the distribution of the salts in the masonry, stone materials sampled at different depth from the wall matrix and saline efflorescences were analysed. Different physical techniques w…

X-ray CT imaging as a scientific tool to study the capillary water absorption in sedimentary rocks used in cultural heritages

This paper proposes the X-Ray CT imaging as appropriate tool for investigating the capillary water absorption in sedimentary rocks. This technique, in fact, provides information useful for deeping the knowledge about of the porosity and the kinetics of the water capillary absorption in porous materials. The possibility to improve in non invasive manner, the understanding of this phenomenon, constitutes a fundamental aspect to take actions in the restoration and conservation of lapideous artifact and monuments from cultural heritages. The investigated sedimentary rocks come from different Sicilian quarries and were used for the building of the Greek temples in the archaeological areas of Agr…

Noise reduction for magnetic resonance imaging by wavelet. An application to the study of the capilary water absorption in sedimentary rocks

FROM LABORATORY TO IN-SITU NUCLEAR MAGNETIC RESONANCE DIAGNOSTICS: AN APPLICATION TO BUILDING MATERIALS OF THE GREEK-ROMAN THEATRE OF TAORMINA

Datazione mediante la tecnica della TL: Il teatro greco-romano di Taormina

Analisi critica delle curve di rilassamento in materiali lapidei provenienti da beni culturali.

Cinetica di assorbimento dell’acqua tramite NMR Imaging per la valutazione della efficacia di trattamenti idrorepellenti

L'efficacia dei trattamenti normalmente impiegati per proteggere e/o consolidare materiali lapidei può essere valutata mediante la tecnica di imaging a risonanza magnetica nucleare (MRI), che consente di studiare in modo quantitativo, non invasivo, non distruttivo, la cinetica di assorbimento capillare dell'acqua. In campioni omogenei (Pietra di Lecce) si forma un fronte piatto (con una discontinuità netta alla scala di misura) e la tecnica MRI permette di seguire la cinetica in quanto consente di misurare, in funzione del tempo, l'altezza raggiunta da tale fronte in qualunque sezione interna del campione. Vengono confrontati i risultati ottenuti sullo stesso litotipo utilizzando due divers…

STK15 overexpression in HCT116 cells causes mitotic disorders and hypodiploidy associated with centrosome amplification.

Double pulse laser induced breakdown spectroscopy applied to natural and artificial materials from cultural heritages

Abstract The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown in recent years its great potential for rapid qualitative analysis of materials. Thanks to the possibility to implement a portable instrument that perform LIBS analysis, this technique is revealed to be particularly useful for in situ analysis in the field of cultural heritages. The purpose of this work is to evaluate the potentiality of LIBS technique in the field of cultural heritages, with respect to the chemical characterization of complex matrix as calcareous and refractory materials for further quantitative analyses on cultural heritages. X-Ray Fluorescence (XRF) analyses were used…

Toward integrated diagnostics for porous materials by means of traditional techniques and NMR: a national network of laboratories

Applicazione di trasformate wavelet per la riduzione del rumore nelle immagini NMR di rocce sedimentarie

Il sempre crescente interesse verso i Beni Culturali suscita molteplici problematiche inerenti la salvaguardia e la diagnosi del loro stato di conservazione. In questo ambito, lo studio delle caratteristiche, quali ad esempio le proprietà capillari delle rocce sedimentarie, ricopre un’importanza cruciale non solo per studiare lo stato di conservazione ma anche per fornire utili indicazioni sulle possibili tecniche e sui materiali da utilizzare negli eventuali trattamenti di protezione e restauro. Al fine di ottenere approfondite informazioni sulle proprietà capillari, il presente lavoro propone un metodo matematico utile nello studio della cinetica di assorbimento capillare. Lo studio è sta…

Comparison of LIBS and micro-XRF measurements on bronze alloys for monitoring plasma effects

The laser-induced breakdown spectroscopy (LIBS) technique is often used as atomic spectroscopic technique for elemental analysis of materials. However, it presents some drawbacks that make an accurate quantitative analysis difficult. Since the plasma properties, such as spatial inhomogeneity and plume stoichiometry strongly depend on the experimental conditions, the measurements are less reproducible. In order to evaluate the measurement fluctuations, we propose to use the more established micro X-Ray fluorescence (μ-XRF) technique for validating LIBS data. In particular, the quantitative data, obtained by varying the laser fluence, the shot numbers and the temporal acquisition parameters, …

RECENTI CONTRIBUTI ALLA CARTOGRAFIA DEL RISCHIO ARCHEOLOGICO DELLA SICILIA: L’APPLICAZIONE DI METODOLOGIE INTEGRATE

Nell’ambito dell’elaborazione della Cartografia di Rischio dei Beni Culturali in Sicilia, sono stati presi accuratamente in considerazione le caratteristiche di alcuni siti archeologici, mediante la sperimentazione di metodologie e tecniche già applicate positivamente per l’investigazione di rocce e formazioni geologiche porose. Il Patrimonio Culturale è relativamente diffuso nell’Isola, grazie alle passate civiltà, fornendo numerose opportunità di studio sia in campagna, sia in laboratorio, ponendo le basi di successive integrazioni ed elaborazioni dei dati raccolti. I materiali dei monumenti storici appartengono a diversi terreni sedimentari, che presentano una relativa complessità geolog…

Confronto TAC – MRI per lo studio della cinetica di assorbimento dell’acqua in materiali lapidei

Vengono messe a confronto due tecniche, la Risonanza Magnetica (MRI) e la tomografia assiale computerizzata (TAC), per ottenere informazioni quantitative sulla cinetica di assorbimento dell’acqua in sezioni interne di materiali lapidei. Entrambe le tecniche permettono di studiare adeguatamente il fenomeno. Nel caso in cui si formi un fronte di bagnamento, come per la Pietra di Lecce, l’analisi delle immagini consente di determinare in modo quantitativo l’altezza di risalita in funzione del tempo ed i dati possono essere interpretati alla luce del modello di Washburn per l’assorbimento capillare. Nel caso in cui il fronte non si formi, come per campioni di biocalcareite provenienti da una ca…

Water capillary absorption in porous media in different wettability conditions studied by Quantitative MRI and X-ray CT

X-ray computed tomography (CT) and magnetic resonance imaging (MRI) have been successfully applied to study both the capillary properties of several samples of Lecce stone and the performances of treatments used for protection and conservation of historical stone artifacts. The presence of water inside the sample may be visualized by both MRI and X-ray CT. For the treated samples, the different dynamics of water absorption gives indirectly the efficacy of the polymer in the rock.

Double Laser LIBS and micro-XRF spectroscopy applied to characterize materials coming from the Greek-Roman theater of Taormina

The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown, in recent years, its great potential for rapid qualitative analysis of materials. The possibility to implement a portable instrument that perform LIBS analysis makes this technique particularly useful for in situ analysis in the field of cultural heritages. The aim of this work is to compare the results, obtained by LIBS measurements with X-Ray Fluorescence (XRF) ones, on calcareous and refractory materials coming from the Greek-Roman theater of Taormina. Calibration curves for LIBS and XRF were obtained by measuring certified reference materials and using them as standards. LIBS measurements we…

Noise reduction in magnetic resonance images by Wavelet transforms: an application to the study of capillary water absorption in sedimentary rocks

Magnetic resonance imaging (MRI) is a powerful technique to study capillary water absorption kinetics in sedimentary rocks. However, the noise in the images can limit the correct identification and the quantitative measurement of the average height reached by the wetting front inside the porous material where imbibition occurs. Therefore, denoising methods can be applied to improve the image quality for a more accurate analysis, without the disadvantages of longer acquisition times. This study attempts to improve the signal-to-noise ratio of the images acquired by MRI on a sedimentary rock (Pietra di Lecce) using a waveletbased thresholding technique. The idea is to average some slightly di…

Aurora-A/STK15 transcriptional silencing and Vincristine treatment show a synergistic effect in human tumour cells

Datazione mediante la tecnica dellaTL: Il teatro greco-romano di Taormina