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This paper reports and discusses the results of some experimental investigations carried out with the aim to identify the best conditions for a safe exposure of the 3D printed large-scale replica of Michelangelo’s David during its exhibition in the Italian Pavilion of the Expo 2020 Dubai.The whole project posed numerous challenges due to the dimension of the Michelangelo’s David (which is over seven metres high and weighs more than five ton). As a matter of fact, on the one hand, no standardized procedures have been still established to define accuracy and quality of 3D printing. On the other hand, the large-scale printing opens up new issues concerning the mechanical properties requested of the printing material and the printing set-up that is necessary to ensure the stability and durability of the printed replica.After a general picture of the whole project, thermal characterization of the material used to print the replica and mechanical tests of samples obtained form the replica are reported and discussed. Thermal characterisation showed that the stiffness of the material was strongly influenced by temperature and that it decreased continuously as this parameter increased. Mechanical tests showed a brittle behaviour, with a collapse load approximately 10 times higher than the internal loads resulting from the self-weight alone.The analyses here presented constitute some of the groundwork carried out for the realisation and installation of the 3D printed replica of Michelangelo’s David. This conceptualisation, considering both the extreme environmental conditions and the large-size of the replica, has been particularly challenging and the adopted procedure was useful to verify the different phases of the realisation of the replica.

Che cos’è una città? [Apertura al numero], Tracce Urbane. Rivista Italiana Transdisciplinare di Studi Urbani, N. 7 (2020): Per una genealogia degli studi urbani critici/ Towards a genealogy of critical urban studies

The 18th century wood-stone-brick sluice system for the regulation of the water-level in the defensive moat is a part of the Archaeological Site of the Timi?ora Fortifications of Bastion VII (Eugene of SAVOY) and was discovered in April 2013 during the construction works of City Business Centre, Block E. The investment's beneficiary decided to save the sluice system by its extraction, relocation, and partial reconstruction within the building complex. To carry out this complex operation, was asked to analyse the state of preservation of the wooden material and to propose the appropriate preservation measures. The reconstruction concept proposed by the beneficiaryi mplied outdoor exposure and maintaining the wooden components in water for public display. The novelty of the concept led us to resort to international specialists in the field. Based on the conducted analyses and on the consultations with them, we developed the preservation strategy for the period between dismantling and reconstruction, as well as the one following the reconstruction.

Presentazione di attività e competenze dell'Istituto in merito al legno nei beni culturali

This paper deals with the description of the analysis performed to characterize the state of preservation of the wooden artefacts recently discovered at the site of Herculaneum, Italy. During 2009, several wooden artefacts were brought to light during maintenance work at Herculaneum. They were attributed to both the roofing elements and the ceiling of the House of the Relief of Telephus. The roof was found mainly disassembled; nevertheless, it was an extraordinary archaeological find, because it represents a unique vestige of a Roman roof and, moreover, the aspect of both the structural and the decorative panels, where portions of the original polychrome decoration and traces of gilding were still preserved, appeared almost intact. Within the framework of the Herculaneum Conservation Project, a diagnostic study was undertaken to characterize the state of preservation of the wood constituting the roof, and also including the decorated panels of the ceiling, in order to determine a consolidation process able to structurally support the decayed wood without damaging the residual polychrome decoration. The results of the micromorphological, chemical and physical characterization of the wood, as a combined diagnostic process, are reported. A first proposal of a possible consolidation methodology based on the analytical results is also suggested.

The present chapter deals with the main characteristics of those adhesive products normally used for the reinforcement of timber structures, generally achieved through a site-applied bonding procedure. The characteristics relate to a combination of the chemical composition and the formulation characteristics of the products. A section dealing with testing procedures specifically intended for products to be used on site has also been added, as this aspect does not exist in current European standards. The principal issues associated with the use of those products, mainly relating to long-term duration aspects, are considered, providing more of the adhesive characteristics and features of the adhesive rather than the wood substrate. Finally, some challenges are introduced in order to improve research in this field.

Present work describes the chemistry at the basis of standard PVAc-D3 products, explaining the role of the cross-linking agent and also giving some insights into the function of Al3+. Furthermore, the possible role played by these compounds in determining some inconveniences, such as formaldehyde release during time, glueline colouring, acidic pH, indirect staining of wood and equipment corrosion, is also described: it is shown how formaldehyde emissions are mostly related to the curing agent, and that both wood staining and glueline discoloration are related to the presence of Al3+. Finally, we showed how understanding those mechanisms constituted the basis for the development of a new generation of PVAc-D3 glues characterised by a good adhesion to wood surfaces, and exhibiting neither corrosive nor chromatic alteration evidences as well as absence of formaldehyde, thus allowing the compliance to the ultimate strictest legislations in terms of formaldehyde emission (CARB, E1-plus) in wood products.