Heat and moisture promoted deterioration of raw silk estimated by amino acid analysis

Silks are amongst the most precious artifacts of our textile heritage. While most silk fabrics are made from degummed silk, some in collections, such as ancient Chinese Juan, are composed of raw or just partially degummed silk. Such silks with remnant sericin gum may require special consideration for their optimum preservation. Conservators and curators then need to know which of the silks in their collections are in this category, and what effect the sericin has on the ageing of silk fibres. In the study reported here, the artificial heat and moisture ageing of raw silk was investigated by means of amino acid analysis. Amongst various amino acid molar ratios, Asp/Gly proved a valuable indicator of residual sericin gum on aged silk. Measurement of the tyrosine content was also useful for gauging the conservation state of silk in some circumstances. The results of the amino acid analyses when combined with those for tensile tests suggested that sericin did not inhibit fibroin deterioration under the ageing conditions employed.     

Electronic paramagnetic resonance as a tool for studying the blackening of Carrara marble due to irradiation by a Q-switched YAG laser

Several authors or practitioners have remarked that Q-switched lasers have an immediate blackening effect on mineral pigments such as vermilion (HgS), minium (Pb₃O₄), white lead [2PbCO₃. Pb(OH)₂], malachite [Cu₂CO₃.(OH)₂] and yellow ochre (FeOH₂). A similar blackening effect can also be obtained on veined Carrara marble. This stone contains several trace elements, particularly iron and manganese. The latter is responsible for a particular response in electronic paramagnetic resonance spectroscopy (EPRS). We investigated the effect of a Q-switched Nd:YAG laser irradiation on the EPRS trace of Carrara marble. Further experiments were performed with the same analytical tool on synthetic calcite powders that had been doped with iron or manganese. It appeared that no significant change of EPRS trace could be put into evidence after laser irradiation of both bulk Carrara marble or doped calcite powders, although some samples had actually blackened. It is concluded that the blackening effect is not due to an oxidation of manganese ions. Colour measurements were also performed within the framework of this investigation. They showed that the colour shift to black is proportional to the fluence applied to the stone surface     

Chemical and isotope characterization of lead finds at the Santa Barbara nuraghe (Bauladu, Sardinia)

Twenty lead finds, unearthed in Late Bronze–Early Iron Age levels at the Santa Barbara nuraghe situated at Bauladu in Sardinia (Italy), have been examined. Their chemical composition has been determined using the ICP-MS plasma-mass technique (Cu, Fe, As, Ag, Sn, Sb, Bi, Zn, Cs, Tl, Mo, Cd, In, Te, W, Th, U, Li, Se). Lead isotope ratios (208/206, 207/206, 206/204) have also been determined. The results are discussed in relation to the mineral source and some aspects of the metal extraction processes. The finds are composed of high purity lead obtained using a smelting at low temperature. Based on the isotope ratios it has been possible to establish that the metal originated from Sardinian ore deposits type.     

Approach to environmental risk analysis for the main monuments in a historical city

The analysis of environmental risk in historical cities facilitates the development of conservation strategies that can minimize the deterioration of historical heritage sites. Risk maps built with GIS software provide information about the probability of the main hazards in a region, and is a very useful tool to identify, evaluate and prioritize the restoration budget of a city in order to manage preventive conservation. In this paper, new methodologies are applied based on the vulnerability matrix and its relationship with static and structural factors, climate conditions, air quality and social agents. This technique has some obvious advantages in the application of risk analysis for cultural heritage conservation, such as the capability of simultaneous risk assessment and geographical references. The vulnerability study implies an on-site diagnosis analysis and requires an adapted protocol for archaeological heritage. The validation of this methodology was carried out in the historical town of Merida (Spain) with a GIS application (ArcGIS software), where the main monuments of this UNESCO World Heritage site were studied.     

Computer aided analysis of the buildings

This paper examines how information systems can assist experts to analyse the state of conservation of buildings of historic importance. The main focus is on image compression, characterisation and recognition, all of which are fundamental for defining a database on the state of conservation. In particular, an overview of available methods is presented for characterising the structure of materials and recognising the various degrees of degradation. A new unified approach to image compression, characterisation and recognition is also proposed. Applications are included for processing stone images.     

Discrimination of painting binders subjected to photo-ageing by using microspectrofluorometry coupled with deconvolution analysis

Organic binding media found in paintings exhibit characteristic fluorescence properties that strictly correlate with their chemical composition and may vary as a function of the ageing time. The aim of this work was to investigate the capability of microspectrofluorometry to distinguish between different binders. Linseed oil and protein-based media, deposited as thin films on microscope glass slides both in the presence and in the absence of inorganic pigments, were examined before and after artificial photo-ageing. Cross-sections of some paint layers were also examined. The article points out that microspectrofluorometry coupled with deconvolution analysis can be a useful tool for distinguishing between oil- and protein-based media. The curve-fitting analysis furnished a fine characterization of each binder/pigment combination, and highlighted the small spectral differences between their fluorescence signals.     

A critical analysis of the Nollywood film Osuofia in London

This article analyzes Nigeria’s Nollywood film Osuofia in London [Ogoro, K. (Producer & Director). (2003/2004). Kingsley Ogoro Productions] to understand how the film synthesizes African and Western cultural identities via the prisms of hybridity and postcolonial theory. The paper uses a critical approach within the contexts of three tenets (African, Western, and hybrid) to read the film. The analysis resulted in five themes: African/folk belief systems and Christianity; traditional Igbo attire and English garb; African/folk music and Western music; African and Western food and drinks; and African/traditional medicine and modern medicine. The analysis indicates that unequal power relations and the forces of globalization are inescapable. Even though the protagonist, Osuofia, challenges the Western ideology, he reproduces it as well.     

Interpreting the age of the ruins of St. John the Baptist's church with multivariate analysis

Two multivariate statistical tools – principal components analysis and cluster analysis – were applied to aid in the interpretation of the historical development of St. John the Baptist's church (?i?e, Slovenia). With these methods it was possible to distinguish between the types of mortar used in the Romanesque and Gothic time periods. The investigated structure is a ruin with poorly preserved fragments of historical mortars, so tracing the individual stages of its construction proved to be a demanding task. Its chemical composition was determined by inductively coupled plasma mass spectrometry (ICP-MS) and the results of the content of various oxides were statistically evaluated to interpret the age of the southern wall of the church.     

Nanoparticles of calcium hydroxide for wood deacidification: Decreasing the emissions of organic acid vapors in church organ environments

Acetic and formic acid vapors emitted from woodwork in historical organs are very important corrosive agents for lead pipes. These acids are slowly released from the wood both during playing and when the pipes are silent. To inhibit this emission process, the wood surface can be modified, by creating a protective layer with alkaline features. However, a coating of wood is not recommended since this could modify the appearance and create a layer not perfectly compatible with the substrate. For this reason, we propose to use some innovative nanotechnology that has been successfully applied for the deacidification of wood samples coming from the Vasa shipwreck. Application of calcium (or magnesium) hydroxide nanoparticles, with sizes ranging from 30–150 nm, allowed a homogeneous distribution of particles through the surface layer of wood simply by soaking (or spraying) it in a alcoholic (or mixed with less polar solvents) dispersion of nanoparticles. Nanoparticles do not modify the wood appearance and distribute randomly within the first layers of wood. The small size of particles accounts for the high reactivity with CO₂ from the air, to give the alkaline reserve of carbonates that provide high efficacy in the neutralization of gaseous acids. The emission of volatile organic compounds (VOC) from the treated wood was determined by using an emission test cell, Field and Laboratory Emission Cell (FLEC). The results show that the emissions of acetic acid vapor from nanoparticles treated wood was very low (< 70 μg/m² h) during the first 13 month. In contrast, untreated wood emitted high concentrations of acetic acid vapor (200–400 μg/m² h).     

Historical and probabilistic structural analysis of the Royal ditch aqueduct in the Alhambra (Granada)

The structural and historical analysis of the aqueduct of the Alhambra is presented. In the 13th century, Muhammad I built the palatial city of the Alhambra. To provide a water supply, Muhammad I built an irrigation ditch, known as the Royal ditch. The aqueduct was reconstructed in the 18th century in ashlar masonry to replace the original one. This work analyzes the history, geometric modeling, materials and stability of the aqueduct. Due to difficulties in testing and measuring the properties and loads, the Monte Carlo analysis technique is used to analyze stability, where the input parameters are defined as probabilistic distributions. Monte Carlo analysis provides the probability of risk of collapse defined by the geometric security coefficient obtained by means of the theory of limit analysis. Additionally, this technique is used to optimize the thickness of the arch.     

Conceiving multiple markets through network analysis: evidence from the emergence of the World Music market

The idea of multiple markets, conceptualised as a variety of concrete market configurations, was fruitfully developed in the socio-material networks research programme. However, it has not yet been able to solve the following puzzle: the differentiation and specification of multiple markets that exist at the same time in the same place. In this paper, I argue that White’s model of ‘markets from networks’ can contribute to filling this gap, since it is centred on the specification of a market’s structural and cultural boundaries. His model allows for the analysis of concrete market practices intertwined with more abstract concepts of markets formed in discourses that move firms and markets across different levels – from local markets to market sectors. An in-depth analysis of the emergence of the World Music market demonstrates the advantages of employing this model in the analysis of multiple markets.     

Deaf Queer world-making: A thick intersectional analysis of the mediated cultural body

Nyle DiMarco, a Deaf, sexually fluid celebrity, helps audiences reimagine ways of being through mediated representations of his cultural body. Within the framework of a critical intercultural communication study and through a thick intersectional approach, we analyze DiMarco’s personae as texts across three TV shows: America’s Next Top Model, Dancing with the Stars, and Difficult People. First, we attend to his moments of sexual fluidity. Next, we attend to his moments of Deaf Gain. Finally, we attend to his character’s denouncing of the hearing homonormative. Through each performance, a Deaf Queer world-making is conjured, offering discursive possibilities beyond the normative.     

Spectroscopic methods for the analysis of celadonite and glauconite in Roman green wall paintings

One set of samples from wall paintings of the X^th Regio of Italy containing green colours was analysed exploiting different spectroscopic techniques, aiming to identify the pigments used. The possibility to distinguish between glauconite and celadonite, the most common green pigments used in such paintings, was of particular interest. Samples of celadonite from Monte Baldo and glauconite from Belgium were considered as standard materials for comparison. The results obtained using FTIR, EDS, AAS, Colorimetry, Raman and EPR spectroscopies were compared for the identification of the green pigments.     

A procedure to assess the suitability of plaster to protect vernacular earthen architecture

As part of a working definition of a new code of practice, this paper develops a methodology to determine the suitability of plasters manufactured on-site to protect the earthen walls of vernacular architecture buildings. Given the diversity of raw earth construction types, ranging from massive earth to stone masonry with earth mortars, and the variability of the materials used, two on-site tests (a shrinkage test followed by a shear test) were proposed. Those tests, as well as additional tests, were performed with lime/sand, earth/sand and earth with plaster admixtures. Lime/sand plasters do not typically pose shrinkage issues, which is why more earth based specimens were tested than lime based specimens. An analysis of the on-site testing complemented with laboratory tests reveals an antagonistic control of the bond between earth plaster and earthen wall based on clay content: an increase in the plaster clay content leads to increased bending strength, which strengthens the plaster and increased shrinkage, which weakens the plaster-wall interface. The heterogeneity of the wall leads to a wide range of results; therefore, this study was conducted to validate the formulation of plasters by means of shrinkage and shear tests at five different points on the wall. The shrinkage test allows finding the earth plaster formulations. Among all the validated formulations, the mason chooses the best one thanks to two criteria: the best workability (which is variable according to masons) with the highest clay content as possible. Then, when the formulation is chosen, the shear test must be done to verify if the bond between the plaster and the wall is high enough. This series of tests allows masons to validate formulations that will ensure good mechanical resistance of the plasters that protect buildings of vernacular earthen architecture.