Scanning electron microscopy and energy dispersive spectrometry analyses of ancient bronze artefacts of the Urartian period from Yegheghnadzor region, Armenia.

The results of the analysis on some fragments of bronze belts and a bowl discovered from southwestern Armenia, Yegheghnadzor archaeological site, are discussed. The samples are dated to the 7 and 6 BCE from the Urartian period. The artefacts were corroded, and a multilayer structure was formed. To study the stratigraphy of layers and their composition, the samples were analysed using scanning electron microscopy and energy dispersive spectrometry (scanning electron microscopy (SEM)-EDS) and optical microscopy techniques. The bronze finds appear with the typical incrustations, rich in alloy alteration compounds. Concentrations of copper and tin in the alloys were quantified by SEM-EDS: The pattern and the percentage of the alloy are the same for the belts. Regarding the bowl sample, it is constituted by two foils, perfectly in contact but different in colour, thickness and composition. The results evidenced that only two elements participate in forming alloy composition in the samples: Cu and Sn. The tin content is variable from 7.75% to 13.56%. Other elements such as Ag, As, Fe, Ni, P, Pb, Sb and Zn are lower and more than 1% and can be considered as impurities.

Radiation-modified natural zeolites for cleaning liquid nuclear waste (irradiation against radioactivity).

There have been comparatively few investigations reported of radiation effects in zeolites, although it is known that these materials may be modified substantially by exposure to ionizing radiation. Thus, by exposure to γ-rays or high-energy particles, the charge states of atoms may be changed so to create, and accumulate, lattice point defects, and to form structurally disordered regions. Such a technique may permit the creation, in a controlled fashion, of additionally useful properties of the material while preserving its essential stoichiometry and structure. Accordingly, we present an application, in which the cation-exchange capacity of a natural zeolite (clinoptilolite) is substantially enhanced, for the treatment/decontamination of water contaminated with radionuclides e.g. (134)Cs, (137)Cs and (90)Sr, by its exposure to high-energy (8 MeV) electrons, and to different total doses.

Gamma-radiation induced polymerization of a chiral monomer: a new way to produce chiral amplification.

The treatment of the terpene beta(-)pinene with gamma radiation (at dose level: 150, 300 and 600 kGy) causes its polymerization into a resin and into a dimer. The yield of the resin and of the dimer appears to be linearly dependent to the radiation dose. The structure of the products was studied by FT-IR spectroscopy also in comparison to a reference beta(-)pinene resin prepared by cationic polymerization. A highly ordered structure was found in the case of the radiopolymer in comparison to the resin from cationic polymerization. Polarimetric measurements have shown astonishing enhancement in the optical activity of the radiopolymer and radiodimer in comparison to the starting optical activity of the beta(-)pinene monomer. Also DSC (differential scanning calorimetry) data supports the unexpected highly ordered structure for the beta(-)pinene radiopolymer in comparison to the resin prepared by cationic polymerization. The results have been discussed in terms of amplification of chirality caused by gamma radiation and the implications of this fact on the mechanism of chiral amplification on prebiotic molecules.

Complex organic matter in space: about the chemical composition of carriers of the Unidentified Infrared Bands (UIBs) and protoplanetary emission spectra recorded from certain astrophysical objects.

In this communication we present the basic concept that the pure PAHs (Polycyclic Aromatic Hydrocarbons) can be considered only the ideal carriers of the UIBs (Unidentified Infrared Bands), the emission spectra coming from a large variety of astronomical objects. Instead we have proposed that the carriers of UIBs and of protoplanetary nebulae (PPNe) emission spectra are much more complex molecular mixtures possessing also complex chemical structures comparable to certain petroleum fractions obtained from the petroleum refining processes. The demonstration of our proposal is based on the comparison between the emission spectra recorded from the protoplanetary nebulae (PPNe) IRAS 22272+ 5435 and the infrared absorption spectra of certain 'heavy' petroleum fractions. It is shown that the best match with the reference spectrum is achieved by highly aromatic petroleum fractions. It is shown that the selected petroleum fractions used in the present study are able to match the band pattern of anthracite coal. Coal has been proposed previously as a model for the PPNe and UIBs but presents some drawbacks which could be overcome by adopting the petroleum fractions as model for PPNe and UIBs in place of coal. A brief discussion on the formation of the petroleum-like fractions in PPNe objects is included.