X-ray computed tomography applied to investigate ancient manuscripts

I will describe in this paper the first results of a series of X-ray tomography applications, with different system setups, running on some ancient manuscripts containing iron-gall ink. The purpose is to verify the optimum measurement conditions with a laboratory instrumentation —that is also in fact portable— in order to recognize the text from the inside of the documents, without opening them. This becomes possible by exploiting the X-rays absorption contrast of ironbased ink and the three-dimensional reconstruction potential provided by computed tomography that overcomes problems that appear in simple radiograph practice. This work is part of a larger project of EPFL (Ecole Polytechnique F´ed´erale de Lausanne, Switzerland), the “Venice Time Machine” project (EPEL, Digital Heritage Venice, http://dhvenice.eu/, 2015) aimed at digitizing, transcribing and sharing in an open database all the information of the State Archives of Venice, exploiting traditional digitization technologies and innovative methods of acquisition. In this first measurement campaign I investigated a manuscript of the seventeenth century made of a folded sheet; a couple of unopened ancient wills kept in the State Archives in Venice and a handwritten book of several hundred pages of notes of Physics of the nineteenth century

A 3D journey on virtual surfaces and inner structure of ossa genitalia in Primates by means of a non-invasive imaging tool

Novel bio-imaging techniques such as micro-Computed Tomography provide an opportunity to investigate animal anatomy and morphology by overcoming limitations imposed by traditional anatomical drawings. The primate genital bones are complex anatomical structures whose occurrence in both male penis (baculum) and female clitoris (baubellum) may be difficult to assess in individual cadavers. We tested a 3-step methodological protocol, including different techniques ranging from inexpensive/simple to more expensive/sophisticated ones, by applying it to a sample of primate species, and resulting in different levels of data complexity: (1) presence/absence manual palpation method; (2) 2D X-ray plates; 3) 3D micro-CT scans. Manual palpation failed on 2 out of 23 specimens by detecting 1 false negative and 1 false positive; radiography failed once confirming the false positive, however firmly disproved by micro-CT; micro-CT analysis reported the presence of 9 bacula out of 11 male specimens and 1 baubellum out of 12 female specimens. A different baculum position was identified between strepsirrhine and haplorrhine species. We also aim to assess micro-CT as a non-invasive technique providing updated anatomical descriptions of primate ossa genitalia. Micro-CT 3D volumes showed the surface of some bones as rough, with a jagged appearance, whereas in others the surface appeared very smooth and coherent. In addition, four main types of bone internal structure were identified: 1) totally hollow; 2) hollow epiphyses and solid diaphysis with few or several channels inside; 3) totally solid with intricate Haversian channels; 4) totally solid with some channels (structure of single baubellum scanned). Ossa genitalia appeared as a living tissue having its own Haversian-like channels. The high resolution of micro-CT 3D-images of primate genital bones disclosed additional form variability to that available from genital bone 2D images of previous studies, and showed for the first time new internal and external morphological characters. Moreover, micro-CT non-invasive approach proved appropriate to recover much of scientific knowledge still hidden and often neglected in both museum specimens and primate cadavers only destined to necropsy

X-Ray Computed Tomography In Situ: An Opportunity for Museums and Restoration Laboratories

X-ray Computed Tomography (X-ray CT) is a sophisticated non-destructive imaging technique to investigate structures and materials of complex objects, and its application can answer many conservation and restoration questions. However, for Cultural Heritage investigations, medical CT scanners are not optimized for many case-studies: These instruments are designed for the human body, are not flexible and are difficult to use in situ. To overcome these limitations and to safely investigate works of art on site\u2014in a restoration laboratory or in a museum\u2014the X-ray Tomography Laboratory of the University of Bologna designed several CT systems. Here we present two of these facilities and the results of important measurement campaigns performed in situ. The first instrument, light and flexible, is designed to investigate medium-size objects with a resolution of a few tens of microns and was used for the CT analysis of several Japanese theater masks belonging to the collection of the \u201cL. Pigorini\u201d Museum (Rome). The second is designed to analyze larger objects, up to 200 cm and was used to investigate the collection of the so-called \u201cStatue Vestite\u201d (devotional dressed statues) of the Diocesan Museum of Massa

ARCHAEOMETRIC ANALYSES AND RESTORATION OF SILVER JEWELLERY FROM THE PUNIC NECROPOLIS OF THARROS – CAPO SAN MARCO (SARDINIA, ITALY)

The paper reports and discusses data from archaeometric analyses and restoration intervention carried out on an assemblage of silver jewellery pieces from the Punic Southern necropolis of Tharros – Capo San Marco (Sardinia, Italy), a site whose relevance is primarily linked to its stratification, extending from the Nuragic age to the Middle Ages. Belonging to a funerary equipment from a primary incineration tomb, confidently ascribable to 7th-6th century BCE, the jewels were found in a precarious state of conservation, extremely fragmented and, in some cases, held together by a surface alteration layer. High-resolution X-rays CT allowed gaining insights into working techniques and decorative features of the finds under study, whose legibility was severely compromised by the alteration layer. OM and SEM-EDS analyses were also performed, to achieve a more exact characterisation of the alteration products. Obtained data allowed, on the one hand, to establish possible contact with North Africa and, on the other hand, to carry out a meticulous restoration intervention, fully respecting the original integrity of the artefacts despite the precarious state of conservation

Chemical analysis and computed tomography of metallic inclusions in Roman glass to unveil ancient coloring methods

This paper describes the analysis of two near-spherical metallic inclusions partially incorporated within two Roman raw glass slags in order to elucidate the process that induced their formation and to determine whether their presence was related to ancient glass colouring processes. The theory of metallic scraps or powder being used in Roman times for glass-making and colouring purposes is widely accepted by the archaeological scientific community, although the assumption has been mainly based on oral traditions and documented medieval practices of glass processing. The analysis of the two inclusions, carried out by X-ray computed tomography, electrochemical analyses, and scanning electron microscopy, revealed their material composition, corrosion and internal structure. Results indicate that the two metallic bodies originated when, during the melting phase of glass, metal scraps were added to colour the material: the colloidal metal–glass system reached then a supersaturation condition and the latter ultimately induced metal expulsion and agglomeration. According to the authors’ knowledge, these two inclusions represent the first documented and studied finds directly associated with the ancient practise of adding metallic agents to colour glass, and their analysis provides clear insights into the use of metallic waste in the glass colouring process.This paper describes the analysis of two near-spherical metallic inclusions partially incorporated within two Roman raw glass slags in order to elucidate the process that induced their formation and to determine whether their presence was related to ancient glass colouring processes. The theory of metallic scraps or powder being used in Roman times for glass-making and colouring purposes is widely accepted by the archaeological scientific community, although the assumption has been mainly based on oral traditions and documented medieval practices of glass processing. The analysis of the two inclusions, carried out by X-ray computed tomography, electrochemical analyses, and scanning electron microscopy, revealed their material composition, corrosion and internal structure. Results indicate that the two metallic bodies originated when, during the melting phase of glass, metal scraps were added to colour the material: the colloidal metal-glass system reached then a supersaturation condition and the latter ultimately induced metal expulsion and agglomeration. According to the authors' knowledge, these two inclusions represent the first documented and studied finds directly associated with the ancient practise of adding metallic agents to colour glass, and their analysis provides clear insights into the use of metallic waste in the glass colouring process

Calibration-free 3D ray-tracing beam hardening correction in computed tomography

In this paper we introduce a calibration -free beam -hardening correction technique in computed tomography, which improves the results achieved by a state-of-the-art correction method. Two main practical points are here underlined: (1) the need to perform a beam hardening correction without previous calibration; (2) the need to consider the shape of the object in all its whole three-dimensional extent. The proposed method requires: (a) a first complete reconstruction of the object by means of a cone -beam filtered back projection algorithm; (b) a segmentation of the reconstructed volume; (c) the construction of the attenuation when varying path -length graph; (d) the interpolation of the experimental data on the graph with a convenient mathematical function; (e) the correction of the measured attenuation values; (f) to perform again the complete cone -beam reconstruction. The result is an effective beam -hardening calibration -free correction over a large variety of objects, easy to use and quite fast. The proposed method results particularly useful when both the measurement time and the control of the geometry of the system are limited, like the ones generally faced in Cultural Heritage diagnostics. Computed Tomography reconstructions for test samples and for real cases are provided to highlight the effectiveness and the advantages of the new suggested approach

Tomography of Cold-Water Corals-Bearing Cores

X-ray Computed Tomography is a non-destructive technique to resolve internal structures and their three-dimensional visualisation. Computed Tomography presents a wide spectrum of application in earth sciences and proves useful to unravel the architecture of sedimentary cores, including those containing cold-water corals. In particular the application of Computed Tomography not only discloses the presence of corals in the core and facilitates taxonomic identification up to species-level, but elucidates also their three-dimensional distribution and taphonomic aspects. The advantages offered by Computed Tomography-scan are continuously growing and is becoming a standard method of analysis for cold-water coral-bearing cores studies

Disclosing 3D Shape of Ossa Genitalia in Primates

Selection pressures on copulatory systems rapidly shape the anatomy of external genitals, affecting both the occurrence and form (size+shape) of baculum (os penis) and baubellum ( os clitoridis ) in primates. These heterotopic bones are usually located within the distal end of the penis and clitoris. However, the pattern of occurrence within the primate phylogenetic tree and the multitude of forms shown cannot be easily merged into a univocal functional interpretation. This study aims to develop a methodological protocol to supply a suitable dataset of bone virtual volumes. These data are useful in morphological approaches exploiting both traditional and geometric morphometric techniques. We provide results on samples from both captive individuals (i.e. fresh samples from corpses coming from zoos or research laboratories) and museum samples (i.e. the primate collection of “La Specola” Natural History Museum, Florence, IT). We followed a three-step protocol which entails progressive sophistication: (1) manual palpation (efficient for fresh tissues, much less so for museum tissues made stiff by either alcohol or formalin); (2) X-rays (confirming or not the palpation); (3a) if absence is confirmed, histological analysis is performed focused on hypothetical traces of cartilage or osteocytes; (3b) if presence is confirmed, high resolution 3D images are obtained by using a non-invasive microtomography system which allows the exploration of both the external and internal structure of bones. The main objectives of the research were (1) completing the primate genital bone occurrence matrix at the specific level, and (2) providing morphological data to test evolutionary hypotheses by overlapping form variation to reproductive and ecological correlates

A mobile computed tomography system for on-site cultural heritage analysis

In consequence of the increasing request of on-site analysis the availability of portable systems for imaging paintings and other works of art has become really an issue for cultural heritage investigation. In many cases, authorities do not allow to transport paintings and works of art outside museums because of their value. We thus developed and used successfully a transportable X-ray Computed Tomography (CT) system that the operators can transport in a regular van and then mount inside museums or conservation centers. The system is composed of spare components that have to be properly mounted and carefully aligned in order to perform the radiographic or tomographic analysis. The basic elements are a 200 kV X-ray tube and a 12x12 cm2 flat-panel detector. With this system, it is possible to scan painting and works of art up to 1.5x1.5 m2 of size thanks to three mechanical translation axes. In the tomographic mode, a rotating platform provides high-resolution rotation of the object carrying up to 50 kg in weight. The operators control all the components of the system with a remote connection computer at a safe distance. In the present work, we report details about the development of this transportable X-ray CT system, we describe how it operates and the technical solutions we used and we show examples of application to real case studies with their specificity