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Roman and Early Medieval bronze artifacts from the Middle Tiber Valley: Technological and conservation insight through optical microscopy, Raman spectroscopy, SEM-EDS, and electrochemical analysis
No full textThis study focuses on microstructure, chemistry, and patina characterisation of eleven archaeological bronze artefacts from
two contexts of the Middle Tiber Valley (Viterbo, Central Italy). The samples were unearthed in the cistern at Spoletino
(1st -4th century AD) and in the late Roman-early Medieval necropolis of Castel Sozzio (5th-7th century AD). They were
analysed using optical microscopy (OM), micro-Raman spectroscopy (μ-Raman), Scanning Electron Microscopy with
Energy-Dispersive X-ray Spectroscopy (SEM/EDS), and electrochemical investigations. OM explored corrosion products
on the surfaces, highlighting mineralogical and structural heterogeneity of the patinas. SEM-EDS analysis showed the
presence of binary (Cu-Sn) and ternary (Cu-Pb-Sn) alloys with minor and trace elements. The binary alloys were used for
good hardness artefacts, and the ternary ones for those that required easy metal working. Selective enrichment and depletion
of the alloying metals produced broad chemical variations and structural heterogeneity in the patinas. Micro-Raman
spectroscopy revealed different corrosion products such as cuprite (Cu2O), lazurite (Na7Ca(Al6Si6O24)(SO4)(S3)·H2O),
malachite (CuCO3Cu(OH)2), and phosgenite (Pb2Cl2CO3). The presence of lazurite in two samples was linked to sulphurrich
burial environments, while phosgenite was linked to the interactions with Cl and a CO2-rich burial environment.
Metallurgical practices, such as slow cooling rates and lead segregation during casting, promoted mineralogical and structural
heterogeneity in the patinas due to interactions with the burial environment, where decomposition of organic matter
occurred. Electrochemical data permitted the estimation of the corrosion rates for all artefacts at remarkably low levels
(0–0.1 mm/year), reflecting stable burial conditions and the protective nature of the patinas. These results suggest that
the burial environments in the Middle Tiber Valley were non-aggressive, facilitating the development of layered patinas
influenced primarily by oxygen and carbon dioxide from humus-rich soils, with a lesser contribution from salts
Enhancing Factual Consistency in Large Language Models: An Integrative Paradigm of Grounding and Self-Prompting Methods for Hallucination Minimization
No full textGli effetti delle decisioni della Corte costituzionale nel giudizio in via incidentale. L'insegnamento di Alessandro Pizzorusso
No full textThe author reviews Pizzorusso’s studies on the effects of Constitutional Court decisions. This review highlights many topical aspects of his thinking, which are still the subject of doctrinal reflection and the search for solutions in jurisprudence
