Vibrational and diffusional dynamics of water in Mg50-A zeolites by spectroscopic investigation

The spectral substructure of the O–H stretching mode of water confined in Mg50-A zeolites is demonstrated, in full hydration conditions and in the temperature range 20–80°C, using Fourier transform Infrared (FT-IR) spectroscopy. Band shapes have been fitted to individual components, according to the actual theories for associated liquids, and three major constituent peaks were derived, at 3230?cm^?1 (ω₁), 3460?cm^?1 (ω₂), and 3600?cm^?1 (ω₃). They have been related, respectively, to an ice-like molecular environment and other hydrogen-bonding configurations. A detailed quantitative analysis of their centre frequencies and relative intensities, traced over the full temperature range investigated, has led to the conclusion that these subbands show direct evidence, under confinement, of bifurcated hydrogen bonds (BHB) among three water molecules as a main feature of the structure of liquid water. The most interesting result comes from the observation, at all temperatures, of the tetrahedral connectivity typical of bulk water. In this sense, we attributed to the zeolitic surface a ‘structure-maker’ role on physisorbed water. This role becomes particularly relevant at the lowest temperature, where the ice-like contribution appears to be the favoured one even under confinement. Furthermore, preliminary results are presented of an incoherent quasi-elastic neutron scattering (IQENS) investigation of the diffusional dynamics of water in the same system, at T=20°C, analysed in the framework of the Confined Diffusion Model (CDM).     

Iron-Age bronze statuettes in Southern Portugal: combining archaeological data with EDXRF and BSEM + EDS to assess provenance and production technology

A simple, fast, and nondestructive analytical methodology combining X-ray Fluorescence (EDXRF) and Back-scattered Electron Microscopy coupled with Energy Dispersive Spectroscopy (BSEM+EDS) has been applied to characterize the alloy’s composition of ex-votos metal statuettes of unknown provenance and age stored in the Museum of Évora in Southern Portugal, and to compare it with Iron-Age artefacts of similar typology recovered from the well-known Phoenician settlement (7th century BC) of Alcàcer do Sal located about 50 km W of Évora. The aim of the study was two-fold: (a) to confirm the age and provenance of the bronzes from the Alcàcer settlement; (b) to assess whether the combined archaeometric approach could shed light on the interaction between local (Iberian peninsula) and allochtonous (Phoenician) technological know-how and on how the “Orientalizing” Phoenician influence had been modulated locally in the making of metal artifacts. In this respect, for comparative purposes, selected bronze statuettes displaying “Orientalizing” features of inferred Phoenician origin from the Nuragic collection of the National Archaeological Museum in Cagliari and the G.A. Sanna Museum of Sassari, Sardinia, were also analyzed by EDXRF. Results indicate that all statuettes are made of an alloy of Cu/Sn or Cu/Sn/Pb with variable Sn and Pb content. The presence and content of Pb and of Fe (the latter always >0.05 %) in the alloy suggest a production technology involving the smelting of ferrous minerals and/or the use of reducing firing conditions with locally available Pb intentionally added as fluxing agent. The alloy’s compositional data is consistent with a provenance of the Évora statuettes from the known Phoenician settlement of Alcàcer do Sal in Southern Portugal.     

A FT-IR absorption analysis of vibrational properties of water encaged in NaA zeolites: evidence of a “structure maker” role of zeolitic surface

Linear polyisoprenes having dimethylamine end groups were prepared by high vacuum anionic polymerization techniques using 3-dimethylaminopropyllithium as the initiator. The amine group was reacted with 2-cholesteryl-2-oxo-1,3,2-dioxaphospholane to provide polymer chains having end zwitterionic groups chemically connected with cholesterol. The association behavior of these end-functionalized polymers was studied in cyclohexane by low angle laser light scattering, dynamic light scattering, and viscometry. The aggregation numbers, N _w were found to decrease by increasing the molecular weight of the precursor polymer, due to excluded volume repulsions. The ability of cholesterol to form liquid crystal mesophases facilitated the association process leading to higher N _w values. The hydrodynamic behavior of the aggregates was similar to that of star polymers. The dependence of the N _w values on the molecular weight of the base polymer, the polydispersity of the associates and the absence of critical micelle concentration, cmc are compatible with the linear head-packing model. Received 29 April 2002 and Received in final form 13 November 2002 Published online: 11 March 2003     

Combined XRF‐SEM analysis of varnished pottery: the case of Syracuse and Adrano (Sicily) archaelogical finds

Micro‐destructive and non‐destructive X‐Ray fluorescence techniques and scanning electron microscopy coupled with energy‐dispersive spectrometry have been applied for the analysis of ten samples of Hellenistic black‐varnished pottery, coming from archaeological excavations in Syracuse and Adrano (South Italy, Sicily). Micro‐morphological and compositional investigations, together with statistical data processing, have shown several differences among the varnishes of the specimen found in the two sites. In particular, Syracuse varnishes are characterised by a more homogeneous composition and well‐defined raw materials, whereas Adrano samples show a higher variability, probably linked to the use of different raw materials and the poorer quality of the varnish as well. The obtained results attest that, as Syracuse black pottery is concerned, the production technique is at an advanced level, whereas Adrano manufacture seems to be less specialised. Copyright © 2012 John Wiley & Sons, Ltd.     

Combining chemical data with GIS and PCA to investigate Phoenician–Punic Cu-metallurgy

This study focusses on the development and application of an innovative protocol which combines chemical data, GIS (geographical information system) and PCA, involving numeric (chemical composition) and categorical (typology of object, archaeological context, chronology and geographical areas) variables, as a simple tool to help in the visualisation and interpretation of large multidisciplinary datasets on Cu-based alloy archaeological artefacts influenced by Phoenician–Punic contacts. The protocol is a useful tool for highlighting existing connections between specific alloy chemical compositions, the location of the original settlement where the artefact had been produced and the proximity to mining resources, waterways, and allochthonous presence such as, in the specific case of this study, the Phoenician and Punic influence in the Iberian bronze production during the Late Bronze Age–Iron Age. The protocol was tested successfully in a case study concerning the precise dating and provenance of bronze statuettes of unknown age and provenance from the Evora Museum collection in Southern Portugal where it confirmed and further refined earlier hypotheses based solely on archaeological and/or chemical studies. The results were interpreted with a unique perspective, to validate the GIS system in combination with experimental chemical-physical data to yield the identification of metallurgical sites of bronze production.     

A multi‐technique approach for the characterization of decorative stones and non‐destructive method for the discrimination of similar rocks

In this paper, a multi‐technique approach, at different scale of observation, is used to characterize a group of decorative stones and to permit to distinguish rocks with similar aspect but coming from different areas. In particular, the samples under study are sedimentary and metamorphic rocks, widely used as building blocks of modern and historical constructions and sculptures. The petrographic and mineralogical features of such rocks were performed by optical microscopy and Raman and Fourier transform infrared absorbance spectroscopies. These techniques permitted to obtain a complete structural, textural, and mineralogical characterization. At elemental level, the investigation was carried out by X‐ray fluorescence (XRF). In particular, XRF and Raman measurements were collected using portable instrumentations, whose advantages for the in situ analysis have been pointed out. The obtained results evidenced the high discriminant capability of the portable XRF for the decorative stones especially when this method is coupled with mineralogical and petrographic information. In this context, we propose to create a database for precious ornamental stones, which could be a starting point for a non‐destructive characterization, even useful for provenance study and/or certification of origin. Copyright © 2013 John Wiley & Sons, Ltd.