390 research outputs found
Cooperative bene comune
No full textIl presente volume nasce con l’ambizioso obiettivo di comprendere come e perché l’impresa cooperativa costituisca uno strumento valido per la costruzione e la gestione condivisa dei beni comuni. Per raggiungere questo obiettivo, al volume hanno contribuito diciannove autori tra accademici e cooperatori. Il libro è composto da tre sezioni: ‘identità, valori ed obiettivi’, ‘buone pratiche e nuovi orizzonti cooperativi’ e ‘startup cooperative’. Come nel caso del ‘The Co-operator’ di King, che creò una guida pratica e teorica per i cooperatori del futuro, il volume aspira a riaprire un dialogo tra gli accademici, impegnati nello studio dell’impresa cooperativa, ed i cooperatori. Un dialogo all’insegna del bene comune
Pre-consolidation of decayed Angera columns with ammonium phosphate : a pilot study in a Milanese courtyard of XVI Century
No full textAngera stone is a lithotype widely employed in Lombardy (north Italy) for ornamental elements/frameworks of
historical buildings. Owing to decay processes it is affected by detachments, exfoliations, pulverizations with
consequent loss of material. The traditional application of synthetic organic products on the Angera surfaces had a
significant role in the decay processes as well (Colombo et al., 2006). Over the last years, the boundaries of
Conservation Science have been pushed toward the use of inorganic-mineral treatments that are stable, durable, highly
transpirable and more compatible with the stone substrates. Ammonium phosphate [DAP, (NH4)HPO4], one of the most
recent inorganic-mineral treatment, is based on the reaction between a water soluble precursor with carbonatic
substrates; the newly formed crystalline phases are able to restore the lost cohesion of the microstructure. Recent studies
investigated the interactions of DAP solutions with calcite of marbles and limestones (Matteini et al., 2011; Possenti et
al., 2016). To the best of our knowledge, no data are available on the application of DAP to: i) the conservation of
dolostones; ii) the pre-consolidation of decayed stones.
Therefore, in this study we explored the potentialities of DAP treatments as a pre-consolidating agent for white
Angera stone. DAP solutions were vaporized on vertical specimens to avoid mechanical contact with decayed surfaces.
The research evaluated the effects induced by the molarity and the application method (repeated applications, wetted or
dry substrate, comparison with paper poultice) on the surface and the influence of pre-consolidation on the subsequent
consolidation with DAP.
The formation of specific crystalline phases and their diffusion inside the first few microns of the stone matrix were
investigated following a multi-analytical approach (SEM-EDS, Raman and IR spectroscopies, XRD). The research
outcomes supplied outstanding indications for restoration, supporting the application of DAP pre-consolidating
treatments to Angera columns strongly decayed in a Milanese courtyard of XVI Century.
Colombo, C., Conti, C., Realini, M., Sansonetti, A. (2006): Diagnostic studies aimed to conservation works in S. Fedele church
(Milan). Proceedings of HWC Congress (Heritage, Weathering and Conservation), Taylor & Francis Group, 917-922.
Matteini, M., Rescic, S., Fratini, F., Botticelli, G. (2011): Ammonium phosphates as consolidating agents for carbonatic stone
materials used in architecture and cultural heritage: preliminary research. Int. J. Archit. Herit. Conserv. Anal. Restor., 5, 717-736.
Possenti, E., Colombo, C., Bersani, D., Bertasa, M., Botteon, A., Conti, C., Lottici, P.P., Realini, M. (2016): New insight on the
interaction of diammonium hydrogenphosphate conservation treatment with carbonatic substrates: a multi-analytical approach.
Microchem. J., 127, 79-86
Calcium phosphates crystallized on Carrara marble after phosphate-based consolidating treatment
No full textDiammonium hydrogen phosphate (DAP, (NH4)2HPO4) solutions have been introduced in the conservation field as a new inorganic-mineral treatments to consolidate or protect decayed carbonatic stone materials of historical monuments [1]. The treatment forms calcium phosphates through a dissolution and re-crystallization reaction, which takes place between hydrogen phosphate groups of the reagent and calcium ions of calcite of the substrate. Calcium phosphates nucleate on calcite grains with a pseudomorphic replacement reaction, and form a crystal network able to restore the lost cohesion of the microstructure. Despite the high number of studies on the crystallization of calcium phosphates and their formation on the surface of carbonatic substrates, only a few studies explored the formation of calcium phosphate phases on marbles treated with DAP and using calcite of the substrate as unique source for calcium ions [2-4]. Previous studies revealed a non-stoichiometric reaction that lead to the formation of a mixture of phases, each one characterized by different Ca/P molar ratio, solubility and stability [4]. In this study, we carry out a non-destructive synchrotron radiation grazing incidence X-ray diffraction (SR-GIXRD) investigation on DAP-treated marbles to determine how the mineralogical composition of the stone substrate affects the crystallization of stable and metastable calcium phosphates. The analyses were performed on Carrara marble specimens treated by capillarity by 0.76 M DAP solutions. Our results indicate that the presence of compositional micro-heterogeneity of Carrara marble favours the formation of specific phases. In general, the composition and the localization of the phases directly depend on the availability of free Ca2+ ions. Dicalcium phosphate dihydrate, a calcium phosphate with a low Ca/P molar ratio, is formed on carbonatic phases with a low Ca content, such as dolomite grains and Mg-containing veins. Octacalcium phosphate (OCP, Ca8(HPO4)2·5H2O) and poorly-crystalline partially-substituted hydroxyapatite (HAP, Ca5(PO4)3OH) are the foremost newly-formed phases when the substrate is mainly composed by calcite.
This study shed light on the potentialities of SR-GIXRD as a powerful non-destructive tool for the diagnostic of Cultural Heritage objects, since it allows investigating the conservation history of stone materials with an in depth evaluation of DAP consolidating processes [5].
[1] M. Matteini, S. Rescic, F. Fratini, G. Botticelli Int. J. Archit. Herit. Conserv. Anal. Restor. 2011, 5, 717.
[2] M. Kamiya, J. Hatta, E. Shimada, Y. Ikuma, M. Yoshimura, H. Monma Mater. Sci. Eng. B 2004, 111, 226.
[3] S. Naidu and G. W. Scherer J. Colloid Interface Sci. 2014, 435, 128.
[4] E. Possenti, C. Colombo, D. Bersani, M. Bertasa, A. Botteon, C. Conti, P. P. Lottici, M. Realini Microchem. J. 2016, 127, 79.
[5] E. Possenti, C. Colombo, C. Conti, L. Gigli, M. Merlini, J. R. Plaisier, M. Realini, G. D. Gatta Appl. Phys. A 2018, 124, 383
Prefazione a Marco Realini (a cura di), La scienza delle vetrine: Analisi dei rischi della conservazione (Roma: CNR Press, 2016)
No full textPrefazione Riccardo Pozzo «Il concetto, l’organizzazione e il funzionamento dei musei sono categorie completamente da innovare per rispondere adeguatamente all’attuale domanda sociale di fruizione delle risorse culturali» . Così recita la descrizione del quinto sottoprogetto, «Museologia e museografia», del Progetto Finalizzato CNR per i Beni Culturali approvato dal CIPE il 28 giugno 1995 con un finanziamemtno di 115 miliardi di lire per il quinquennio 1996-2000. Non a caso, dunque, il presente volume curato da Marco Realini nasce nel quadro della collaborazione strategica tra il CNR e il Laboratorio Museotecnico Goppion Spa, siglata dall’accordo di ricerca congiunta del 14 ottobre 2013 per l’analisi dei rischi connessi alla conservazione del patrimonio in ambiente espositivo. Ogni contributo dà conto dello stato dell’arte, nella convinzione che il corretto progetto di una vetrina da museo debba partire dai dati scientifici che assicurano la conservazione del patrimonio stesso. «Innovazione sociale e culturale» è un sintagma divenuto di uso corrente negli ultimi anni per via del nome scelto dallo European Strategy Forum Research Infrastructures per il gruppo di lavoro che si occupa delle infrastrutture per le scienze umane e sociali . In sé e per sé, l’innovazione significa creazione di nuovi prodotti e servizi che portano sul mercato una nuova idea. Oggi si è d’accordo che la ricerca di base sia sì curiosity driven, ma abbia al contempo un impatto traslazionale, poiché è il trasferimento di conoscenze a rendere possibile l’innovazione, che è product driven, in quanto genera nuovi prodotti e linee di produzione. L’innovazione è competenza dei consigli delle ricerche di tutto il mondo, che sono assai diversi dalle università e dalle accademie, che risalgono rispettivamente al Medioevo e le accademie al Rinascimento. Le università hanno come missione l’insegnamento e i professori sono però liberi di insegnare e fare ricerca su cosa piace loro di più; mentre le accademie furono istituite dai re che volevano che degli scienziati vivessero a corte averli per avere risposte su questioni di loro, dei re, interesse. I consigli delle ricerche, invece, furono istituiti attorno alla prima guerra mondiale per ottenere risultati di rilevanza strategica per i loro paesi. Le scienze umane e sociali si studiano al CNR da poco più di mezzo secolo, dalla riforma degli enti di ricerca firmata dal romanista Riccardo Orestano, Decreto Legge 2 marzo 1963, n. 283. Da quel momento il CNR ha reso possibile una travolgente evoluzione del contesto scientifico delle scienze umane e sociali, che ha messo capo a importanti scoperte tecnologiche, un esempio per tutti sono le biblioteche digitali, che al CNR sono attive dal 1964, e ad altrettanto importanti applicazioni industriali, e qui l’esempio da fare riguarda l’evoluzione delle tecniche di restauro degli artefatti con la quale il CNR permise al paese di reagire con efficacia ai disastri provocati al patrimonio culturale dall’alluvione di Firenze del 1966. È il caso di ricordare che il CNR nel 1971, con il Professor Sabatino Moscati, fece partire il progetto finalizzato ai beni culturali e che da allora noi al CNR abbiamo prestato un appoggio e una passione a 360 gradi sulla questione dei beni culturali. Importa sottolineare che al centro di queste ricerche è stato l’oggetto sociale, materiale o immateriale, ma sempre posto da una persona, cosa che richiede oggi un ripensamento rispetto agli sviluppi della tecnologia. Non si tratta di verificare se le macchine funzionino, si tratta di vedere invece quali siano le domande che l’essere umano pone nel suo cammino sulla via humanitatis. La conoscenza, la conservazione e la fruizione del patrimonio non solo sono funzionali alle politiche d’integrazione, ma promuovono anche la crescita culturale, economica e sociale. Si pensi alla conoscenza e alla conservazione di contesti culturali e di artefatti, all’archeologia post-bellica, alla realtà virtuale e alla museografia sostenibile , l’impatto delle quali dà come risultati: a) rendere il patrimonio culturale lo strumento per azioni di diplomazia scientifica e culturale; b) proteggere e promuovere la diversità culturale; c) documentare, conservare, monitorare, fruire il patrimonio, e infine e) proteggerlo da minacce ambientale e antropiche nel Medio Oriente e nel Nord Africa. La Milan Declaration on Culture as an Instrument of Dialogue among Peoples adottata all’unanimità dai ministri della cultura di ottanta paesi a conclusione della conferenza internazionale del 31 luglio-4 agosto 2015 organizzata dal MiBACT in Expo2015 a Milano afferma che: «Cultural Heritage is the mirror of history, civilization and of the society, which is expected to protect it. Cultural Heritage, both tangible and intangible, is also the essence of identity, the memory of peoples and their past and present civilizations. It expresses, at the same time, universally recognized values of tolerance, dialogue, and mutual understanding...the work of man and his extraordinary talent must be protected and preserved for the benefit of future generations» . A Bruxelles, l’approccio strategico alla diplomazia culturale ha fatto valere la diversità culturale come parte integrante dei valori dell’Unione Europea. La Joint Communication to the European Parliament and the Council: Towards an EU Strategy for International Cultural Relations (8 giugno 2016) dell’Alto rappresentante dell’Unione per gli affari esteri e la politica di sicurezza indica i seguenti cinque principi guida: «(a) Promote cultural diversity and respect for human rights. (b) Foster mutual respect and intercultural dialogue. (c) Ensure respect for complementarity and subsidiarity. (d) Encourage a cross-cutting approach to culture. (e) Promote culture through existing frameworks for cooperation» . L’attuale crisi dei migranti e dei rifugiati ha chiarito con terrificante efficacia quanto sia urgente per le amministrazioni locali, regionali, nazionali e internazionali metter mano a politiche di innovazione sociale e culturale a vantaggio dei nuovi cittadini, per accoglierli con piena dignità. La grande sfida è il passaggio dalla data science alle data humanities. L’Unione Europea ha riconosciuto la necessitò di fornire strutture avanzate per ricerca di frontiera sull’innovazione sociale e culturale. L’obiettivo principale è considerare gli aspetti scientifici e tecnologici del settore, offrendo soluzioni innovative alle sfide sociali del nuovo millennio. Di fatto, peraltro, anche i ricercatori delle scienze umane e sociali sono confrontati ogni giorno con masse enormi di dati e con una crescente complessità in contesti altamente interdisciplinari. Pensiamo a tecnologie abilitanti quali: «NFC-Near Field Communication; CRM-Content Rights Management; contents-aware networks (fruition and enjoyment); low-latency networks (warning and security); and huge-bandwidth networks (augmented reality)». L’obiettivo del volume curato da Marco Realini è mettere a disposizione di lettori, esperti, e tecnici soluzioni top-rate per museografia sostenibile e sistemi espositivi avanzati. Al momento, sei infrastrutture di ricerca per «Social and Cultural Innovation» sono pronte e funzionanti e tra queste, E-RIHS (European Research Infrastructure for Heritage Science), che crea sinergie per un approccio multidisciplinare all’interpretazione, conservazione, documentazione e management del patrimonio culturale . Il volume è un contributo di sostanza e qualità per la realizzazione del grande progetto italiano di guidare la ricerca europea per la scienza del patrimonio culturale
Application of ammonium phosphate to marble. Investigation of newly-formed calcium phosphates with synchrotron light and high lateral resolution FTIR microspectroscopy
No full textInorganic-mineral treatments exhibit great potentialities for the consolidation of stone materials due to their high compatibility with the substrate. Their reaction mechanism is based on the diffusion, inside weathered stone matrixes, of water soluble precursors that, reacting with the substrate, supply a crystal network able to reconnect detached grain boundaries. The newly-formed crystalline phases are stable and due to their low solubility provide a passivating action toward atmospheric agents even in acid environment. Diammonium hydrogen phosphate [DAP, (NH4)2HPO4] has been recently suggested for the treatment of sedimentary and metamorphic carbonatic decayed stones. The reaction of DAP with calcite of the substrate involves a pseudomorphic replacement and favours the growth of calcium phosphates inside the porosity. Preliminary studies (Matteini et al., 2013; Possenti et al., 2016) show that the reaction at room temperature is non-stoichiometric and induces the formation of hydroxyapatite [HAP, Ca5(PO4)3(OH)] (Ni & Ratner, 2003) and other metastable phases. In this pilot study we characterized the complex assemblages of calcium phosphates formed after DAP treatments on Carrara marble specimens with a multi-analytical approach (scanning electron microscopy, vibrational spectroscopies and powder X-ray diffraction). A set of quarried and thermally decayed samples were treated by poultice and capillarity using DAP solutions at different molarities. Ground-breaking techniques such as X-ray diffraction with synchrotron light in transmitting geometry and high lateral resolution FTIR microspectroscopy were employed to overcome some of the analytical limits of conventional approach, assessing the overall composition of main and trace phases as well as
their arrangement on the substrate. Preliminary findings show the formation of a shell-like layer around the calcite grains, composed by a mixture of crystalline and amorphous calcium phosphates; the formation of specific phases, their morphologies and the relative amount depend on the solution molarity and the treatment duration. Moreover, our data show a correlation between the kind of crystalline phase and its morphology and position within the shell structure.
Matteini, M., Colombo, C., Botticelli, G., Casati, M., Conti, C., Negrotti, R., Possenti, E., Realini M. (2013): Ammonium phosphates
to consolidate carbonatic stone materials: an inorganic-mineral treatment greatly promising. Proceedings of the Built Heritage
2013 Monitoring Conservation Management, 1278-1286.
Ni, M. & Ratner, B.D. (2003): Nacre surface transformation to hydroxyapatite in a phosphate buffer solution. Biomaterials, 24, 4323-
4331.
Possenti, E., Colombo, C., Bersani, D., Bertasa, M., Botteon, A., Conti, C., Lottici, P.P., Conti C. (2016): New insight on the
interaction of diammonium hydrogenphosphate conservation treatment with carbonatic substrates: a multi-analytical approach.
Microchem. J., 127, 79-86
Crystallography and Cultural Heritage: study of caoxite formed after a conservation treatment
No full textIn Cultural Heritage field, whewellite (CaC2O4•H2O - COM) and weddellite (CaC2O4•(2+x) H2O - COD) play a relevant role for a twofold reason: they are the main components of a particular kind of film found on the surface of many works of art and they also occur in a conservation treatment for carbonatic substrates [1], due to the reaction between ammonium oxalate solution and calcite of the substrate. In order to obtain a more homogeneous and deeper diffusion of the treatment into decayed materials, we focused our experiments on an alternative method using diethyloxalate [(C2H5)2C2O4] which during the hydrolysis transforms calcium carbonate into calcium oxalate [2]. The reaction between diethyloxalate and calcite produces COM, COD and an unexpected relevant amount of caoxite (CaC2O4•3H2O - COT). The crystallization of COT into the treated carbonatic substrate is the main proof of the reaction between diethyloxalate and the decayed stones, thus its identification is essential to monitor the treatment and define its efficacy. Due to the scarce literature data, an extensive investigation of crystallographic, spectroscopic and microscopic features of COT has been performed, including the development of a new method for its synthesis [3]. The experiments clearly highlight the role played by the H2O molecules linked within the structure by different kinds of hydrogen bonds. The vibrational assignment of the infrared and Raman bands is critically proposed. The fact relevant for the work in biomedicine, cultural heritage and crystallography is that a simple examination of the spectra allows quickly to determine the chemical nature of the material in an unknown sample even in a minute quantity or in awkward experimental conditions.
[1] B. Doherty, M. Pamplona, R. Selvaggi, C. Miliani, M. Matteini, A. Sgamellotti, B. Brunetti, Appl. Surf. Sci. 2007, 253, 4477.
[2] C. Conti, I. Aliatis, M. Casati, C. Colombo, M. Matteini, R. Negrotti, M. Realini, G. Zerbi, J. Cult. Herit. 2013, 15, 336.
[3] C. Conti, M. Casati, C. Colombo, E. Possenti, M. Realini, G.D. Gatta, M. Merlini, L. Brambilla, G. Zerbi, Spectrochim. Acta A, 2015, 150, 721
Use of LA-ICP-MS technique with SEM-EDS analysis in the study of finishing layers
No full textThe investigation of the finishing layers in artworks is of main concern, as important information on the artistic technique can be suggested. The study is usually carried out by Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS), but in those cases when very similar compositions are detected, more sensitive techniques are called for. Laser Ablation-Mass Spectrometry equipped with Plasma source (LA-ICP-MS) allows a very sensitive element analysis of solid surfaces sampled by means of a laser. It is an emerging methodology, only in a few cases applied in the field of Cultural Heritage. The integration of the two techniques has been studied and applied on the finishing layers of Baroque stucco decorations, in order to define the artistic technique in terms of raw materials, stratigraphy and working tools
Non-destructive evaluation of ammonium oxalate treatment penetration depth using micro-SORS
No full textThe determination of the penetration depth of treatments is a crucial issue in conservation science for assessing treatments efficacy. Micro-spatially offset Raman spectroscopy (micro-SORS), that permits the
non-destructive collection of Raman photons generated under the surface of a turbid material, here has been used to non-destructively retrieve the distribution of oxalates formed after ammonium oxalate (AmOX) treatment on plasters. Two sets of samples treated with AmOX have been studied, namely plaster mock-ups and plaster fragments collected from the painted façades of Palazzo Besta in Teglio (Sondrio, Italy). The evaluation of the distribution of the newly formed oxalates was carried out considering the slope of the oxalates/calcite Raman bands intensity decay trend with increasing micro-SORS defocusing distance. Micro-SORS outcomes were found to be consistent with those obtained with conventional
micro-Raman performed on cross-section, confirming the extension of this innovative method to the evaluation of treatments efficacy
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