A visible and long-wavelength photocured epoxy coating for stone protection

An epoxy coating modified by PDMS hydroxyl terminated is presented in this paper in order to evaluate its potential use as a protective of a stone surface. With a view to its use in restoration sites, visible and long-wavelength photoinitiated cationic polymerization is proposed here. The system investigated is based on a crosslinking mechanism which shows remarkable advantages for stone protection, such as the low toxicity of the products and facility of mixture preparation. Furthermore, the visible light exploitation represents the most important advantage, because it is easy to apply in a restoration site, with or without irradiation instruments. Besides coating characterization through FT-IR, DMTA analyses and contact angle measurement on glass slides, analyses were also carried out on coated plaster samples. These analyses were performed in order to evaluate the effectiveness of the protective, in relationship to hydrophobicity (contact angle measurement, capillary water absorption) and morphology surface changing (SE/SEM observations, colorimetric measurements) before and after polymer application and UV aging test of coated samples. The overall characterization makes it possible to consider it a suitable coating for stone protection.     

Study of silica nanoparticles – polysiloxane hydrophobic treatments for stone-based monument protection

The growing interest in the conservation of historic buildings encourages the development of water-repellent materials and methodologies to consolidate and/or protect stones. Recently, particular attention was devoted to composites of inorganic oxides nanoparticles and hybrid siloxane or silicone polymers. Here we present a study on the water repellence of a thin protective coating obtained through sol-gel process starting from Glymo and Dynasylan 40®, and loading the silicate matrix with nano-sized silica particles (Aeroxide LE1® -Degussa-Evonik). The coatings were applied to limestone, sandstone and granite samples. The silica nanoparticles have been characterized by XRD, the siloxane matrix through micro-Raman spectroscopy, while the surface morphology was examined by SEM. The efficacy of the treatments has been evaluated through static contact angle measurements and capillary water absorption. The optical appearance of the coatings was evaluated by colorimetric measurements. Nanoparticles at suitable concentration gave high values for the static contact angle (up to ∼ 150°), for all stone species even for four months exposure to atmospheric conditions. The coatings, in the water capillary absorption tests, however, behave as expected only for granite even if the long-term water direct contact reduces the hydrophobicity.     

Quantitative modeling of blistering zones by active thermography for deterioration evaluation of stone monuments

Infrared thermography for stone monuments to date has primarily focused on qualitative analysis to judge the location of defect zones using relative temperature differences, but there are difficulties in mapping a blistering zone and quantitatively calculating its area. Therefore, this study used quantitative modeling to map blistering zones with graduated heating thermography. To achieve this goal, the following steps were performed: acquisition of thermographic images by passive and active methods, construction of a temperature distribution curve, establishment of the critical temperature and transitional zone, classification of the relative deterioration grades of the blistering zone, monochrome processing, vectorization, and deterioration evaluation of the blistering zone. After evaluating the blistering degree of the specimen through modeling, the total areas and rates were calculated as 359.3 cm² and 80.1%, respectively. This study was very useful for identifying the location, area, and relative degree of deterioration of blistering zones that were not easily detectable with the naked eye. In the future, if quantitative modeling of blistering zones is actively applied to deterioration maps, the reliability of deterioration evaluation for stone monuments will be improved, and additional deterioration, such as scaling, may be prevented.     

Assessment of synthetic polymeric coatings for the protection and preservation of stone monuments

The performance of five synthetic coatings for the protection of stone monuments of Hellenistic and Byzantine period has been evaluated. The selected coatings included four commercially available siloxane-, siloxane/acrylic- and perfluoroether-based compositions, as well as a new composition based on newly synthesized fluoro-organosilane. The coatings were applied onto petrologically different stone substrates, such as marble, travertine, sandstone and a newly baked brick compatible with Roman period bricks, used for the restoration processes in Galerius Palace, Thessaloniki, Greece. The coatings' protective efficiency was investigated by measurement of water–stone contact angles, water vapor permeability, and water absorption by capillarity. The optical properties of the applied coatings were also investigated and they were also ranked with regard to their optical characteristics.     

Consolidation and protection by nanolime: Recent advances for the conservation of the graffiti,Carceri dello Steri Palermo and of the 18th century lunettes,SS. Giuda e Simone Cloister,Corniola (Empoli)

Nanolime dispersed in 2-propanol was extensively used for the consolidation of wall paintings. The knowledge of the advances of this methodology dealing with all the possible effects associated with the nanolime new material in conservation is fundamental to assess and improve the technique. In this paper, four different dispersions of Ca(OH)₂ nanoparticles were characterised by Small Angle X-rays Scattering technique (SAXS) and Transmission Electron Microscopy (TEM) in order to achieve information on size, shape, polydispersity, agglomeration, and crystal structure (by SAED patterns) of the particles. Once characterised, the dispersions were tested in two different case studies, the Carceri dello Steri in Palermo with their graffiti and the 18th century lunettes at the SS. Giuda e Simone Cloister, Corniola (Empoli) with their lime-based mural paintings. The treated samples were characterised in relationship to either their morphology and surface chemical composition by Scanning Electron Microscopy coupled with Energy Dispersive X-rays spectroscopy (SEM-EDX), or their water absorption and mechanical properties (resistance to material abrasion). The results obtained showed that all the dispersions were nanometrically structured and their application succeeded in recovering the mechanical properties of the painting or graffito layers, not altering their permeability to water and keeping perfectly the wall transpiration. However, the dispersions constituted of the nanoparticles obtained via a synthesis able to control size and shape of the Ca(OH)₂ particles resulted in a better performance in situ, even if the differences found by SAXS and TEM were slight.     

A new class of gels for the conservation of painted surfaces

The application of a new class of organogels as cleaning tools for painted surfaces is described. It combines some of the most attractive features of cleaning liquids and normal gels while diminishing the deleterious characteristics of both. Thus, the ‘latent’ gellant, polyethyleneimine (PEI), reacts with CO₂ at room temperature in solutions of several organic liquids to produce an ammonium carbamate form (PEICO₂). This charged species organizes itself into 3D polymer networks which immobilize the liquids as gels. The properties of the original solution (i.e. a free-flowing liquid) are re-established immediately after addition of a small amount of a weak acid which displaces the CO₂ molecules and makes the PEI chains positively charged. The visual changes are substantiated by rheological analyses. Results from analytical tests to determine the utility of these gels as cleaning tools for painted surfaces of historical and artistic interest, have been obtained from contact angle and FTIR measurements as well as visual comparisons of the surfaces before and after application of the gels. The analyses indicate that the PEICO₂-based organogels were very effective in removing different surface patinas from painted supports. A surface layer of dammar was completely removed from a test canvas with oil paint, an aged painting from the XIX century, and a XV century oil-on-wood panel attributed to Mariotto di Cristoforo. Finally, a surface acrylic polymeric resin (used in a restoration performed during the 1960s) was also successfully removed from Renaissance wall paintings decorating the Santa Maria della Scala Sacristy in Siena, Italy. The isothermally rheoreversible gel approach described in this work represents a new, highly versatile, and very efficient method for removing aged surface patinas from works of art.     

Biodeterioration of Incralac used for the protection of bronze monuments

Outdoor bronze sculptures are highly susceptible to corrosion in many environments and organic coatings are widely used for their protection. The purpose of this study was to determine the susceptibility of the commonly used coating Incralac to biodeterioration by microorganisms. A yeast was isolated from a bronze statue treated with Incralac and its ability to degrade Incralac was determined using growth curves, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The organism grew slowly on Incralac in liquid culture, but SEM images demonstrated its ability to adhere to Incralac coated metal. Additionally, the yeast caused a rapid drop in the low frequency impedance of Incralac coated metal that was not observed under sterile conditions, indicating that the organism accelerated deterioration of the coating. The potential for microbial growth to accelerate deterioration of Incralac should be considered when developing a maintenance strategy for the protection of outdoor metal monuments.     

The building stones of the ancient centre of Naples (Italy): Piperno from Campi Flegrei. A contribution to the knowledge of a long-time-used stone

Piperno, a Late Quaternary magmatic rock cropping out on the eastern side of the Campi Flegrei (Italy), is probably the most important building stone of Naples, used over a time-span from at least the Roman age until the beginning of the 20th century. Despite its wide diffusion in the monumental architecture of Naples, very little is known about this rock, as regards its technical features, as well as the geological aspects. This paper aims at providing a first overall contribution towards a rediscovery of this long-time-used material, in view of careful restoration works, which nowadays at Naples only take into account the proper geological features of the stone in a few peculiar cases. Thus, it seems of extreme importance to understand the basic parameters of Piperno and, above all, its response to weathering agents. Main mineralogical, petrographical and engineering–geological properties are presented here for the first time, with specific reference to two sampling areas, located at Pianura and Soccavo, in the western sector of the Neapolitan urban area. As far as many of its physico–mechanical features are concerned, Piperno extends over a wide range of values, which allow different varieties of the rock to be identified. This preliminary result is seemingly in accordance with data from old historical literature, which stated the existence of six horizons in the Piperno formation.     

大运河遗产廊道的保护传承与活态利用——以苏州段运河为例

中国大运河是流动着的活态廊道遗产,如何保护、传承和利用运河遗产资源已上升到国家战略的高度。通过实地考察与文献分析,客观归纳当前苏州段运河的发展瓶颈,并借鉴国内外典型线性遗产廊道的成功经验及发展模式,从完善基础设施、美化生态环境、统筹规划旅游产品谱系、创建运河文旅品牌、推动产业融合创新等方面,构建苏州段运河遗产廊道的核心竞争力,服务于地方生态文明建设与社会文化事业发展的同时,以期为中国大运河遗产资源的统筹保护、有效传承与活态利用提供有益参考。     

人本视角下的历史文化名镇保护规划实施评估体系研究 ——以周庄古镇为例

规划实施评估作为城乡规划编制的重要一环,作用日渐凸显,尤其对于历史文化名镇保护规划的实施评估更为重要.其不仅能全面了解保护规划实施效果的真实情况,也利于摸清"家底",找准保护工作中的短板,进而在新一轮保护规划中,以此为要义,有针对性地提出保护措施和发展路径.以周庄古镇为例,将"人"的感受和作用纳入评估对象,坚持真实性、...     

21世纪面向空间规划的荷兰遗产政策

近年来,在遗产保护与可持续发展整合成为国际焦点的背景下,欧洲强调多部门、多尺度、跨区域协调空间发展的空间规划被视为助力保护与发展整合的有力工具.荷兰作为欧洲空间规划的先行者,在21世纪成为欧洲推动遗产政策融入空间规划的先驱之一,20多年来面向空间规划的遗产政策实践体现出3大趋势,即面向"文化空间"的多样遗产整合,从"部...     

江苏国家历史文化名城保护地方立法发展、比较及完善

江苏13座城市入选国家历史文化名城,体现了该地区深厚的文化历史积淀和优秀的城市精神内涵。地方立法作为一种法律保障,对加强历史名城保护、弘扬优秀传统文化、约束各类破坏行为起到重要作用。对江苏10座地级市的名城保护地方立法发展进行梳理,对各市立法名称、目的、体例、保护对象、保护措施、法律责任进行比较研究,提出修订和新增相关立法时可采用的思路和建议,可为丰富名城保护法治理论提供参考。     

Color characterization of roofing slates from the Iberian Peninsula for restoration purposes

Substitution of slate roofing tiles is a conventional operation during building restoration, since tiles are very difficult to restore or clean because of the high degree of alteration they suffer. Criteria for replacement of historical building stones must be based on geological, geotechnical and esthetic parameters, among which color is of great importance. In this sense, this paper constitutes a comprehensive and useful colorimetric study of roofing slates from the Iberian Peninsula, for the purposes of restoration. The color of 50 commercial varieties of roofing slate mined in quarries from the 12 mining districts in the Iberian Peninsula was analyzed with a spectrophotometer device, by considering the CIELAB color space. The results of the study were used to develop a protocol for characterizing the color of roofing slate and to define the color range of roofing slate from the Iberian Peninsula. In addition, the similarities and differences in the color and microstructure of the different commercial varieties of Iberian roofing slate were established and the limit of acceptability of replacement of one type of slate by another was determined. Parameter h_ab was found to be the most important CIELAB color coordinate as regards the formation of homogeneous color groups, and the specular component excluded (SCE) mode was most sensitive as regards detecting color differences between two samples.     

Methods and tools for the classification and cataloging of antique moulds from the collection of the Richard-Ginori factory

This study proposes a procedure for digitally classifying and cataloging moulds which belong to the historic collection of the Ginori porcelain factory in Doccia (Sesto Fiorentino, Italy). In addition to a vast number of antique plaster moulds, this collection includes artistic porcelain artifacts obtained from casting porcelain using the moulds and models made of various materials. The proposed methodology includes two workflows: the first starts with photographic and casting processes conducted recently on various groups of moulds and involves historical surveys for investigating the relationships between the various sets of moulds, the models from which they were derived and the porcelain objects derived from them. The second workflow was applied when no information was available for a set of moulds, and involved 3D scanning of the moulds, with virtual reconstruction of the corresponding model followed by a final art historical survey like that used in the first procedure. 3D scanning techniques and successive model reconstruction can also be applied for obtaining a virtual model in the first process, when the physical model was lost, damaged or never existed. The variety and extent of the Ginori collection suggested the use of a customized Data-Base (DB) and a set of functions designed to manage and extract information, data and archived images. This filing system, called DocciaDigitalArchive (DDA), also makes it possible to specify the relationships between the different typology samples (prototype models, moulds derived from them, handmade porcelain objects produced from these moulds), which are associated when the same subject is portrayed. The DB structure conceived also provides the possibility of incorporating pictures and data of known archetypes. This additional information makes it possible to place each subject in its historical and artistic context. For each sample filed in the DDA system, documentary cards, which summarize data, images, reports and links to other entities or samples connected to the subject consulted, can be viewed on a suitable interface.     

In Search of Stylized Facts on Art Market Prices: Evidence from the Secondary Market for Prints and Drawings in Italy

In the paper we develop some price indices for the secondary market forprints and drawings in Italy for the period 1977–1999. Theempirical evidence suggests the emergence of causal links from thepainting series and consumer price series to the print and drawingsprice series. Within the secondary market, the drawings price seriesprecedes the print price series.     

A procedure for determining the chemical composition of binder and aggregate in ancient mortars: its application to mortars from some medieval buildings in Pisa

The use of a scanning electron microscope equipped with a microanalytical system is proposed for characterising ancient mortars. A calculation procedure is presented that allows a determination of the binder and aggregate compositions (including volatile components) from microprobe data collected on the binder, and chemical, mineralogical, petrographical and physical data collected on the mortar bulk sample. The proposed procedure is applied to 11 mortar samples from three historical monuments built in Pisa throughout the Middle Ages. The binder of the analysed samples consists of a carbonate crystalline fraction and an amorphous carbonate-free fraction that makes up from 20 to 60 % by weight of the binder. The aggregate composition, on average, is close to that of the Arno River sands.     

Different methods for soluble salt removal tested on late-Roman cooking ware from a submarine excavation at the island of Pantelleria (Sicily,Italy)

This paper deals with the comparative evaluation of different procedures of salt extraction designed for archaeological ceramics from submarine burial environments. The experimental work was carried out on a particular type of late-Roman cooking ware finds (Pantellerian ware) found in a shipwreck near the shoreline of the Island of Pantelleria (Sicily). The studied ceramic test-pieces were first recognised in terms of bulk characteristics (mineralogy, petrography and chemistry). SEM-EDS observation allowed verification of the presence of various secondary minerals at the surface and in the pore spaces formed after the prolonged permanence in seawater under oxidising or reducing conditions. Pore-size distribution was also determined in the same fragments that had been subjected to the salt extraction routines. Three salt extraction methods were tested: two methods based on diffusion processes (water immersion under stationary conditions and under mechanical stirring conditions) and one method based on both diffusive and advective processes (multiple packages of sepiolite). The obtained experimental data allowed us to identify strengths and weaknesses of the tested procedures with practical spin-off for archaeologists and restorers (efficiency, kinetics, compatibility with the ceramic substrate, costs and simplicity of use). Salt extraction under mechanical stirring was the most effective method and, for this reason, is suitable for laboratory fieldwork during or immediately after submarine archaeological excavations. Similar advantages are also intended for the preliminary treatments of the most precious findings prior to museum storage.