169,769 research outputs found
The role of political competition in the link between electoral systems and corruption: an extension
No full textThis work provides an extension to an international context of the analysis made by Alfano, Baraldi and Cantabene (2013) on the role of political competition as a channel through which electoral systems affect corruption. Our result conflicts with that found by empirical literature on that topic that makes plurality rules the most virtuous in terms of corruption. Political scientists must be cautious in designing the degree of proportionality of electoral rules without take into account the variation in political competition that follows
In-plane behaviour of NFRCM-strengthened masonry modelled by means of discrete elements
No full textIn the last years, the attention to the use of eco-compatible materials and the development of sustainable solutions for structural strengthening has increased, leading to fibre-reinforced cementitious matrices (FRCM) made by natural fibres (NFRCM, de Carvalho et al. 2017).
NFRCM strengthening systems, in the same manner as FRCM ones, can be considered an alternative to fibre-reinforced-polymer (FRP) reinforcement for masonry structures, to improve the compatibility of reinforcement applied to masonry substrate (di Tommaso et al. 2017).
The numerical assessment of NFRCM and/or FRCM strengthened masonry is an active field of research and it represents a complex task, due to the complexity of both reinforcement and support materials, which can be considered as composite ones. In literature, some macro-models consider both masonry components (bricks and mortar) as a homogeneous continuum, and FRCM layers are considered as an additional equivalent continuum, with the textile fibres assumed as an embedded reinforcement of mortar matrix (Wang et al. 2017). These models have been extended to NFRCM (de Carvalho et al. 2019).
Recently, a simplified micro-model approach was proposed for diagonally loaded masonry panels reinforced with FRCM (Murgo et al. 2021), adopting a 2D FE model with one-dimensional interfaces for masonry panels, and adding a bi-directional grid of trusses for representing the reinforcement.
An updated discrete element model for simulating the in-plane behaviour of masonry walls strengthened with FRCM or NFRCM has been recently introduced by authors (Baraldi et al. 2021). This model is based on an existing discrete or rigid block model having rigid elements and nonlinear one-dimensional interfaces between them, able to represent both mortar joints and brick cracking (Baraldi et al. 2020). Such a model has been improved by considering masonry strengthened on both sides The hypothesis of perfect adhesion between the wall and reinforcement and also between the matrix and fibres of the strengthening system is assumed, in order to avoid the increase of model degrees of freedom with respect to the unreinforced masonry (URM) case. The reinforcement is modelled by means of further stiffness and strength parameters accounting for the FRCM/NFRCM geometrical and mechanical properties.
The proposed model has already turned out to successfully simulate cracking both on masonry and the external reinforcing layers and it was calibrated with respect to an existing simplified numerical model (de Carvalho et al. 2019).
In this work, the proposed discrete model is calibrated and compared with respect to several existing laboratory tests of in-plane loaded masonry panels reinforced with FRCM and NFRCM layers, in order to highlight its effectiveness and potential improvements
Phoenicians preferred red pigments: micro-Raman investigation on some cosmetics found in Sicily archaeological sites
No full textThis research was undertaken in the aim of identifying and getting deeper knoowledge into materials and pigments used in cosmestics concerning the contest of the phoenician settlements in Sicilian territory. In fact, about the typologies of cosmetics in use among the Phoenicians, little is known. On this subject, generally references come from bibliographic latin sources: in antiquity, women preferred to paint white their face, red lips and cheeks, yellowish eyes and black to sorround their look (Pliny the Elder, Naturalis Historia; Ovidius, De medicamine faciei feminae). An interesting aspect of this research is that just one paper is known on Punic cosmetics.[1]
In the Museo Archeologico Regionale “Antonino Salinas” (Palermo, Sicily) an important collection of unguentaries coming from the town of Selinunte is preserved. Some of them, finely crafted, come from the sanctuary of Demetra Malophoros, some unguentaries come from the acropolis and some more from the necropolis (dating from the 6th to the 5th century b. C). The sacred area, excavated by Cavallari (1818) and Salinas (1903-1905), have provided a great amount of archaeological materials. In the area where once the acropolis rose, the remains show a mixed village, Phoenician and Greek. In this study, the findings from Salinas were considered, as well as some others from the Museum Conte Agostino Pepoli (Trapani), from the Museum Baglio Anselmi (Marsala) and from the museum of Mozia. The number of glass and fictile unguentaries, pyxis and alabastra examined were large: 142 items from Salinas, 210 from Mozia, 14 from Pepoli and 117 from Baglio Anselmi.
This research has completed the one carried out on 210 samples from the Museum of Whitaker Foundation from Mozia, a merely phoenician –punic settlement.[2,3]
The samples were analyzed by spectroscopic techniques.
The IR spectra were acquired with a spectrophotometer VERTEX 70 (Bruker) FT-IR, equipped with a detector deuterium triglycine sulphate (DTGS). The setting parameters were: resolution 4 cm-1, spectral range 4000-600 cm-1, number of scans 32. ATR spectra were recorded using an Elmer Golden-Gate accessory.
The micro-Raman spectrometer used in this case was a Labram Model from the Jobin Yvon-Horiba with a spatial resolution of 1 μm and with quick detection ability as a result of the CCD detector 1024x256 pixels cooled to -70°C by the Peltier effect. The spectral resolution was 1 cm-1. The exciting wavelength was the 632.8 nm red line of a He-Ne laser.
Generally the samples were presented as inorganic powders of different colors: white, black, blue and red. Though the samples came from different museums, they were considered togheter, since they belonged all to the Phoenician culture and coming from Trapani archaeological sites.
The white samples were of two types. The first one was mainly composed of gypsum and anhydrite mixtures (e.g. Inv No 1680, 1663, 1753); the other type (e.g. pyxes Inv N° 1393, 1451) was composed of fully carbonated cerussite, gypsum and litharge. The second kind of cosmetic corresponded to the most famous Greek cosmetic, called psymition, used by women to white the skin. The first type suggested that, for the same use, alternative materials, cheaper and most readily available, could be employed in the past.
The black powders, usually used to outline the eyes, were mostly given by carbon obtained from vegetable combustion (e.g. Inv. N° 1566, 2314, 4313) or, sometimes, from bone combustion (animal charcoal) as for the samples Inv. N° 3140, 1761.
A single blue powder (Inv N° 42259) was consisted by the famous Egyptian blue (CaCuSi4O10).
The love for the red color by Phoenician is evident from the great number of powders of this color, probably used to give color to the cheeks or lips. A wide variety of red minerals was found. In many cases the presence of hematite (e.g. Inv N° 2309, 2689, 4269) was detected.
A large number of pink and red powders containing cinnabar (unguentaries Inv N° 1393, 6480-1, 34396) was observed. No frequent and very interesting is in fact the HgS finding powder into alabastra (e.g. Inv. N° 7317/7, 1255), a holder typically used to contain ointments.
Another red pigment was identified as red lead (e.g. Inv N° 1606).
Finally, a singular discovery was the presence of red lead chromates chrocoite and phoenicochroite, two very rare minerals (e.g. sample Inv. N° 805, 1-98-2, 4386). In fact, they have never been previously attested for cosmetic use, and also rarely attested in paintings before the end of the 18th century when it began to be produced industrially.[4]
The high number of Phoenicians samples taken into examination has allowed to understand the typology of raw materials used by the Phoenicians settled in Sicilian contexts.
In this study affects the materials heterogeneity used for the make-up, even for example in comparison to the Roman culture, for which there has come a greater number of samples (sites such as Pompeii, Herculaneum and Oplontis were analyzed by our research group),[5-7] but which revealed a palette less extensive and less refined. In particular, this study identified the use of many kind of red pigments, also very rareof mineral origin.
References
[1] A. Huqet al., Combined, Appl. Phys. A, 2006, 83, 253–256.
[2] G. Freguglia, C. Baraldi, M.C. Gamberini, P. Toti, P. Baraldi, PRIN07- Colors and balms in antiquity: from the chemical study to the knowledge of technologies in cosmetics, painting and medicine. Aboca, Sansepolcro (Arezzo, Italy), 2-3th December 2010, p. 50-51.
[3] C. Baraldi, G. Freguglia, M.C. Gamberini, P. Baraldi, 5-8th September 2011, RAA2011, Parma, 2011, p. 103-104.
[4] R.J.H. Clark. Chimie, 2002, 5, 7–20.
[5] P. Baraldi, C. Fagnano, C. Baraldi, M.C. Gamberini, Automata, 2006, 1, 49.
[6] M.C.Gamberini, C. Baraldi, F. Palazzoli, E. Ribechini, P. Baraldi, Vib. Spectrosc. 2008, 47/2, 82.
[7] E. Van Elslande, M.C. Gamberini, C. Baraldi and P. Walter, An overview of the Raman studies on cosmetic powders from Pompeii, 14-18th September 2009. RAA2009, Bilbao, 2009
A MicroRaman study of some paintings from Tassili (Sahara)
No full textSome investigations on the composition of the powders found in the Egypt desert and used as pigment
Le pitture parietali delle ville di Stabia: materiali e degrado
No full textA partire dal 2009 con una serie di missioni in area stabiana, dopo il rilascio dei permessi da parte della Soprintendenza archeologica di Napoli e Pompei, sono state attuate indagini sulle pitture murali delle ville imperiali (Villa Arianna e Villa San lvlarco) per avere una descrizione dettagliata delle tecniche e dei materiali impiegati nelle pitture murali dei vari ambienti. Sono stati anche programmati controlli sul degrado dei materialj pittorici. Di concerto con archeologi e restauratori presenti sul sito, consapevoli delle operazioni di restauro attuate nel passato e tenendo conto dell'effetto degli eventi drammatici del 79 d.C., si è cercato di capire la situazione conservativa delle pitture per fornire indicazioni sulle operazioni di restauro. Nel corso delle missioni si sono osservate mediante microscopio digitale le superfici pittoriche divari ambienti e si sono effettuati dei microprelievi in posizioni marginali e rappresentative delle cromie presenti. Successivamente i campioni sono stati sottoposti ad analisi presso i laboratori universitari, ad analisi con varie tecniche analitiche e spettroscopìche di tipo atomico e molecolare, come la fluorescenza di raggi X (XRF). la spettroscopia FT-lR in trasmissione e in riflessione, la microscopia Raman con laser rosso e verde.
Una considerevole massa di dati ottenuta con i vari tipi di analisi permette di tracciare una sinossi delle tavolozze pittoriche degli artisti al lavoro, dello stato di conservazione dello strato pittorico, del degrado di alcuni dei pigmenti utilizzati in antico, e della presenza di materiali impiegati per il restauro nel corso dei decenni. Sono state evidenziate opere di mani differenti, in base all'impiego di tonalità realizzate con miscele di pigmenti e con sovrapposizione di materiali diversì. ln alcune aree il cinabro risulta virato in nero con produzione di solfocloruri di mercurio. Le decorazioni a mezzo fresco risultano spesso alterate e soggette a caduta di parti dello strato pittorico
Analisi micro-Raman di polveri cosmetiche greche e puniche
No full textPresso il Museo Archeologico Regionale “Antonino Salinas” di Palermo è conservato un importante nucleo di balsamari provenienti da Selinunte. Taluni, di pregevole manifattura, provengono dal Santuario di Demetra Malophoros. Altri unguentari e balsamari provengono dall’acropoli, altri ancora dalle necropoli. Appartengono ad un periodo compreso tra la metà del VI e la metà del V secolo a. C. L’area sacra, messa in luce durante gli scavi effettuati da Cavallari nel 1818 e da Salinas nel 1903-1905, ha portato alla luce una quantità immensa di materiali archeologici. Nell'area dove prima sorgeva l'acropoli i resti presentano un abitato misto, punico e greco. Al fine di questo studio sono stati inoltre presi in esame anche altri campioni, conservati nei saloni espositivi e in magazzino, provenienti dall’isola di Mozia, insediamento prettamente fenicio-punico.Gli insediamenti da cui provengono i contenitori, Selinunte e Mozia, offrono una gamma di valenze culturali assai variegata che sta a confermare il loro carattere di insediamenti nati da e per lo scambio. Le analisi condotte nel presente lavoro fanno seguito a quelle relative ad un importante gruppo di contenitori cosmetici di età Punica, coevi a quelli qui studiati, conservati presso il Museo della Fondazione Withaker sull’isola di Mozia [1,2].Il nucleo di balsamari fittili e vitrei, pissidi e alabastra considerati è stato ispezionato e si sono raccolte polveri di vari colori.La microscopia Raman ha permesso di identificare e caratterizzare i residui. Campioni bianchi hanno rivelato essere composti prevalentemente da miscele di gesso e anidrite (n inv. 1680, 1663, 1753). Le pissidi n. 1393 e 1451 presentavano residui bianchi composti da cerussite completamente carbonatata, gesso e litargirio. Si tratta del cosmetico greco per eccellenza, denominato psymition, utilizzato dalle donne per conferire pallore all’incarnato.Polveri rosa contenute in balsamari figurati di origine greca hanno mostrato come componenti ematite, quarzo, calcite, anatasio e goetite oppure, nel caso dell’askos zoomorfo n. 610, calcite, ossido di piombo, ematite, carbone e residuo organico. Il contenitore in vetro policromo n. 34228 presentava un abbondante residuo rosso composto da magnetite, quarzo, silicati ed ematite. Una conchiglia del genere Pecten (n. 34396) mostrava residui rossi composti da ematite, magnetite, lepidocrocite, goetite e tracce di cinabro (HgS). Un’interessante polvere rossa, (HgS miscelato con anatasio) è stata rinvenuta all’interno dell’ alabstron n. 7317/7 proveniente dalla necropoli di Marsala (tomba n.34). Risultati simili si sono ottenuti nell’ambito delle precedenti indagini su Mozia relative a contenitori della stessa tipologia. Il rinvenimento di questi pigmenti in associazione ad alasbatra è interessante in quanto la letteratura generalmente indica l’uso dedicato di questi particolari contenitori ad unguenti e profumi. Le analisi del contenuto azzurro della coppetta fittile n. 42259 hanno rilevato la presenza del celebre blu egiziano (CaCuSi4O10).Bibliografia[1] G. Freguglia, C. Baraldi, M.C. Gamberini, P. Toti, P. Baraldi,; PRIN07- Colors and balms in antiquity: from the chemical study to the knowledge of technologies in cosmetics, painting and medicine. Aboca, Sansepolcro (Arezzo, Italy), 2-3th December 2010, p. 50-51[2] C. Baraldi, G. Freguglia, M.C. Gamberini, P. Baraldi, RAA2011 Parma 5-8th September 2011, pp. 103-104
Application of micro-Raman spectroscopy for conservation projects in art and archaeology with a case study on Cappadocia rock-hewn wall paintings
No full textThis paper aims at reporting an overview of the principles and applications of micro-Raman spectroscopy in cultural heritage. Micro-Raman was used for characterizing painting pigments, inorganic binders, degradation materials in artworks with different goals: to know the materials and so the execution technique, to investigate the state of preservation, to establish the authenticity of the artefacts. The micro-Raman analyses were often performed on the occasion of conservative projects and they were able to supply valid and useful information to the conservators during their work. As case study, the project on the investigation of rock-hewn wall paintings in Cappadocia (Turkey) will be shortly presented as exemplificative of application of Raman techniques for the knowledge of the constituent materials, for supporting the conservation work and for detecting degradation products. Analysis were performed in the Interdepartmental instrument Center of Modena and Reggio Emilia University by a bench top system equipped with a microscope allowing for studying in non-destructive way different kinds of samples: powders, cross and thin sections, pre-treated samples
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