Physics

The impact of lighting, heating and people in re-using historical buildings are discussed for the case study concerning the ceremony room (i.e. the Giant Hall) of a mediaeval palace in Padova. The Hall has substantially four major problems for conservation: (i) the impact of heating, lighting and people when the room is used; (ii) many cracks on the oak panels of the coffered ceiling; (iii) the soiling by dust and soot particles deposited on the frescoes; (iv) the stained glass windows. A microclimate study was performed to know the impact of the environmental variables, and the use of the room, on the artworks preserved inside. The study has proved the impact of the lamps (both incandescence and compact fluorescent lamps) on the ceiling, the penetration of external air in the room, the heat and the moisture released by people, the impact of sunshine through windows and the scatter diagram of the daily cycles in temperature (T) and relative humidity (RH). During winter concerts, the strips of lead which are wrapped round the edge of the cut glass pieces in stained glass windows easily drop below the dew point and form condensation, starting corrosion. A discussion concerns the allowed variability, which should not exceed risk thresholds. A safe interval can be established within the area determined by the most frequent T and RH natural cycles. In fact, both of the cycles were compatible with the artefacts, or the artefacts were already damaged to allow the exceeding dimensional changes. Attention should be paid in the variability external to this area, especially approaching or exceeding a limit equal to twice the mode of the natural variability.

The impact of lighting, heating and people in re-using historical buildings are discussed for the case study concerning the ceremony room (i.e. the Giant Hall) of a mediaeval palace in Padova. The Hall has substantially four major problems for conservation: (i) the impact of heating, lighting and people when the room is used; (ii) many cracks on the oak panels of the coffered ceiling; (iii) the soiling by dust and soot particles deposited on the frescoes; (iv) the stained glass windows. A microclimate study was performed to know the impact of the environmental variables, and the use of the room, on the artworks preserved inside. The study has proved the impact of the lamps (both incandescence and compact fluorescent lamps) on the ceiling, the penetration of external air in the room, the heat and the moisture released by people, the impact of sunshine through windows and the scatter diagram of the daily cycles in temperature (T) and relative humidity (RH). During winter concerts, the strips of lead which are wrapped round the edge of the cut glass pieces in stained glass windows easily drop below the dew point and form condensation, starting corrosion. A discussion concerns the allowed variability, which should not exceed risk thresholds. A safe interval can be established within the area determined by the most frequent T and RH natural cycles. In fact, both of the cycles were compatible with the artefacts, or the artefacts were already damaged to allow the exceeding dimensional changes. Attention should be paid in the variability external to this area, especially approaching or exceeding a limit equal to twice the mode of the natural variability.

Two of the seven prehistoric Megalithic Temples of the Maltese Islands inscribed on the UNESCO World Heritage List were covered by a temporary opensided shelter in 2009. This was to protect the Temples from environmental factors, primarily direct rainfall and insolation, which were considered as main causes of deterioration of both the materials and the structures. The sheltering was preceded by intense environmental monitoring which lasted for 1 year and which was then partially continued even after the sheltering. This paper, evaluates the changes in environmental conditions both before and after sheltering and concludes that the advantages of the shelter far outweigh the disadvantages. Caution is, however, advocated in the case of noted disadvantages, such as salt, dust and pollution accumulation on the now protected megaliths, which should continue to be carefully monitored for any possible deleterious effects. Recommendations are also given for maintenance actions which can prevent these events from negatively affecting the state of conservation of the megaliths. These include the dry, soft regular brushing of the megaliths, and the surrounding ground, to remove accumulated salts which can cause the limestone to deteriorate if reabsorbed back into the porous stone either during RH fluctuations or on occasions when condensation events, which have been detected during the monitoring campaign even after the sheltering, occur.

The use of phase change materials (PCMs) in civil buildings as an effective thermal energy storage solution has been well documented in literature and proven in the field. When applied to Cultural Heritage, PCMs' technology needs to be adapted to specific requirements. Besides the important objectives of economic return and human comfort, the indoor microclimatic conditions have to be suitable for conservation purposes. The application of PCMs' technology to Cultural Heritage has been investigated within the European MESSIB (Multi-source Energy Storage System Integrated in Buildings) project. Firstly, several methodologies of incorporation of PCMs in different materials were studied and tested. The thermal properties of gypsum panels and silicon coatings incorporating micro-encapsulated PCMs in the form of powder and emulsion were analysed in the laboratory. Then, PCMs incorporated in gypsum panels in contact with a wooden panel were tested and their effect on the thermal behaviour of the wooden panel was evaluated under thermal cycles in a climatic chamber. PCMs incorporated in silicon coatings in contact with a painting were also tested. Moreover, gypsum panels containing PCMs were tested in the S. Croce Museum in Florence, Italy, where the microclimatic monitoring has shown thermal conditions potentially dangerous for the works of art preserved. The research performed both in the laboratory and on the field confirmed the effectiveness of the PCMs as thermal storage solutions, but also gave evidence on an important drawback when the material incorporating PCMs is in direct contact with an object of art.

The methodology of protecting the European stained glass windows against environmental risk (e.g. meteorological factors, air pollution, microorganisms) by means of an external glazing is not new. In spite of many scientific studies carried out in the last 20 years, some questions were still up for discussion. The European VIDRIO (2002-2005) project gave an answer to these questions. The research carried out by the different project partners established a new multidisciplinary approach aimed at evaluating the efficiency of the protective glazing systems and their effects on stained glass windows conservation, and finally at assessing the most appropriate strategy to preserve stained glass windows. Scientific results showed that the so-called isothermal glazing (i.e. ventilation by the air coming from the inside of the building) protected efficiently the ancient stained glass window from environmental attack (i.e. rain, pollutants, condensation, thermal shocks) with very limited secondary effects. The scientific research highlighted that its efficiency was strongly related to the technical design of the protective system. In particular, the ventilation and the size of the interspace had to be carefully considered. The research developed within the VIDRIO project was turned into general recommendations to the owners and practitioners on the best practice for the stained glass windows future conservation.

We have measured the surface scattering efficiency of a new ceramic composite, based on boron carbide, that was recently proposed for use as a shielding material for pulsed neutron scattering instrumentation. The results show that, due to a relevant presence of clay material in the composite, the surface scattering efficiency is higher than other common shielding materials, which are used on pulsed neutron scattering instrumentation, and suggest revising the material composition.

The impact of climate on cultural heritage surfaces leads to several damage processes and the protection and the preservation of works of art is a challenge for conservation scientists and restorers. Traditional and innovative products are used in consolidating treatments in order to reduce the effects of the interaction environment-materials. The EC NANOMATCH Project aims at the development of innovative consolidating agents for carbonate matrices, wood and glass whose features should result in high compatibility, efficiency and long-lasting effect. In this project, metal alkoxides, molecular precursors for the deposition of metal carbonate are synthesized, characterized, tested and proposed as an alternative to traditional consolidating agents as well as to calcium hydroxide nanoparticles. This paper gives an overall description of the methodological approach adopted for the in field evaluation of durability taking into account the environmental impact. Preliminary results of the analyses carried out on carbonate stones aimed at investigating the features of the consolidating treatment are here presented and discussed.

An innovative, cost-effective, user-friendly and portable device (dew sensor) to directly detect condensation on glass surfaces was developed within the EC-VIDRIO project (contract No. EVK4-CT-2001-00045), aimed at finding sustainable solutions to preserve ancient stained glass windows. The results of the research showed that the direct survey of condensation with the new sensor is more accurate and reliable than the traditional indirect microclimatic measurements. Since the construction of the first prototype, the dew sensor was developed further, continuously improved, validated in the laboratory and applied successfully on different surfaces at sites of interest in the field of Cultural Heritage; on the stained glass windows in the Saint Urbain Basilica of Troyes (France), Sainte Chapelle of Paris (France) and Cologne Cathedral (Germany); on stone walls in Petrarca's Tomb (Padua, Italy) and the Hagar Qim Temple (Malta). Now the sensor is being used in the Lascaux Caves (France). The newly built device was patented (PTC/EP2005/050665) and gave such interesting results that the Italian Ministry of University and Research financially supported a spin-off project that has lead to the creation of a new company (R.E.D. s.r.l.) in order to develop the prototype further and to produce the sensor at industrial scale.

In the framework of the Santiago of Compostela Cathedral program, a multidisciplinary investigation of the porch of the glory was carried out between 2009 and 2011 to identify the main environmental risks and to develop a preventive conservation planto be integrated in the general management strategy of the Cathedral. The study included historic and archivist research, structural studies, mineralogical analyses, biological sampling, cleaning tests and microclimatic monitoring. The main weathering factors and the related damage processes were identified. Results have shown that the main responsible for the observed damage was the infiltration of rainwater through the roof, due to cracks in the structure of the Cathedral. Other environmental factors having a remarkable impact on the state of conservation of the polychrome and its substrate were the solar radiation, the thermo-hygrometric cycles, the particle deposition and the biological growth. Solutions were suggested to improve the environmental conditions, thus reducing further damage.

Research and development of cost-effective, high-performance thermal insulation materials for the construction sector has to be focused on their final application. In particular, solutions for refurbishing historic buildings, which represent 40% of the European building stock, have to offer a good compromise between environmental quality, energy efficiency and conservation aspects. In this paper, the experimental assessment of an insulation material based on aerogel technology, recently developed in the European project EFFESUS, is presented with regard to the material's thermal performance, compatibility with historic fabric and reversibility. The overall results obtained in laboratory testing on a real-size mock-up and in a real-world case application indicate that the new material is a promising solution for retrofitting historic buildings, thanks to its thermal properties, easy application, reversibility and material compatibility.

Wall paintings and architectural surfaces in outdoor environments are exposed to several physical, chemical and biological agents, hence they are often treated with different products to prevent or slow down their deterioration. Among the factors that have to be taken into account in the selection of the most suitable treatment for decorated surfaces, the aesthetic compatibility with the substrate is of great importance in the cultural heritage field; minimizing colour variation after treatment application is a crucial issue in particular for painted surfaces. In the framework of the European Project Nanomatch the color variation induced on wall painting mock-ups by the two innovative consolidants (calcium alkoxides) developed was evaluated using colorimetry in comparison with two traditional products. In this work these innovative consolidants have been also tested in combination with two commercial biocides and the results of colorimetric measurements discussed. Moreover, as the u...

In the field of cultural heritage conservation, wall paintings treatment is a particularly complex issue, which requires a suitable choice of materials. In this paper, two innovative calcium alkoxides, calcium tetrahydrofurfuryl oxide [Ca(OTHF) 2 ] and calcium ethoxide [Ca(OEt) 2 ], are proposed as new products for the consolidation of wall paintings. They were developed during the NANOMATCH European project and their efficacy, compatibility with the substrate and durability were evaluated in comparison with commercial products on both model and real samples. Model samples were exposed in four different sites around Europe to investigate the treatments' behaviour under different climatic conditions. The main research results are reported here: alkoxides showed to be a good option for wall paintings' consolidation especially in presence of certain binders and pigments. Finally, an impact testing device was used for the first time for the evaluation of the consolidants' efficacy and thus proposed as a reliable methodology for their performance assessment.

The measurement of wood thermal expansion at fixed values of moisture content (MC) between the dry state and the cell wall saturation point is a very difficult task, as MC varies with temperature. Being hygroscopic deformations much larger than thermal ones, in order to evaluate the latter, when changing temperature also relative humidity should be adapted. To achieve this goal a special apparatus was designed to vary relative humidity as a function of temperature to keep MC constant, and thus to measure the thermal expansion coefficient without hygroscopic effects. The moisture content was assessed to remain constant by testing the heating cycle of each specimen, keeping the specimen itself on a precision balance before the thermal expansion measurement. The radial coefficients of thermal expansion of ten specimens of Norway spruce were measured at 7.0% and 11.4% MC. No statistically significant differences were found between the two data sets, indicating a negligible effect of moisture content on wood thermal expansion at MC values typical of indoor environments. However, the thermal expansion coefficients measured at 7.0% and 11.4% MC seem to be higher than the values for dry state reported in literature, indicating an effect of the moisture content.

Two infrared reflective coatings recently developed as part of the EFFESUS European 26 research project are characterized and evaluated in this paper. Thermal performance, 27 durability, compatibility with historic fabric, and reversibility are all analysed. The results of 28 extensive research that include laboratory analysis of selected substrates, measurements on a 29 large-scale traditional masonry mock-up, thermodynamic simulations, and finally application 30 in to a real historic building in Istanbul, all support the potential of the new coatings to 31 improve the thermal performance of historic buildings, in keeping with their visual integrity 32 and cultural value. Besides their reflective properties, proven by the thermal stress reductions 33 on the treated surfaces, the new coatings are characterized by low visual impact, easy 34 application, material compatibility, and reversibility after application, as well as durability 35 over time.

The present work was carried out in the Ria de Aveiro Lagoon (Portugal) to better understand the dynamics driving the bioaccumulation processes in edible bivalves, namely in the Manila clam Ruditapes philippinarum. For the first time, a holistic approach was applied, collecting data on sediment physico-chemical characteristics and its contamination, geochemical speciation and metal(loid) bioaccumulation in clams, from three exploited areas of the lagoon (Costa Nova, Torreira, Ílhavo). The Ria de Aveiro Lagoon is part of the Natura 2000 network, has the designation of Special Protection Area (SPA), contains Sites of Community Importance (SCI), it is protected by the EU Birds Directive (79/109/CEE) and includes a natural reserve in its northern part. Specifically concerning the metal(loid) occurrence, the monitoring and the identification of contaminated sites in protected areas are priorities, to improve the biodiversity conservation efforts and to ensure the correct management of natural resources. Results showed that multiple driving forces interacted together to determine site-specific impacts, resulting in different risks at local scale for the transferring of the metal(loid)s to the trophic chain. Hydrodynamics played a major role driving the occurrence of depositional or ablative sites, influencing the granulometric composition of sediments and their contamination; metal(loid) chemical forms were then determinated by multiple factors like pH, redox potential and organic matter content. The geochemical speciation data showed that the Ílhavo area should be considered the most dangerous in terms of clam consumption, since in case of environmental changes, possible conversion of the elements from the potentially bioavailable forms to the bioavailable ones can occur. Moreover, bioaccumulation processes in Manila clam were observed for Cd, Zn and especially As, the latter representing serious risk for consumer safety throughout clam consumption.