Stucco Forte in Venice between the 16th and 17th centuries: the case study of Addolorata Chapel stuccoes in San Pantalon´s Church

Stucco samples of the 17th century were collected from the Addolorata Chapel in San Pantalon's church, which represents an important example of the stucco forte technique in Venice. Stucco forte is usually made adding powdered lime and marble to the gypsum base mixture. However, the exact recipe remain in most cases still unknown as often related to the knowledge and experience of the artisans [1]. The aim of the present work is to characterize and study the chemical-physical composition, the working techniques and the conservation state of the stucco forte in Venice. The samples were subjected to optical and electrical microscopic observation (OM, SEM-EDX), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DSC), and mercury intrusion porosimetry (MIP). Gypsum, and calcium carbonate were found as major components with presence of magnesium carbonate and traces of hydromagnesite. Magnesite and hydromagnesite do not develop within the normal carbonation processes suggesting that magnesium carbonate was intentionally employed for improving the material characteristics

Stucco Forte in Venice between the 16th and 17th centuries: the case study of Addolorata Chapel stuccoes in San Pantalon´s Church

Stucco samples of the 17th century were collected from the Addolorata Chapel in San Pantalon's church, which represents an important example of the stucco forte technique in Venice. Stucco forte is usually made adding powdered lime and marble to the gypsum base mixture. However, the exact recipe remain in most cases still unknown as often related to the knowledge and experience of the artisans [1]. The aim of the present work is to characterize and study the chemical-physical composition, the working techniques and the conservation state of the stucco forte in Venice. The samples were subjected to optical and electrical microscopic observation (OM, SEM-EDX), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DSC), and mercury intrusion porosimetry (MIP). Gypsum, and calcium carbonate were found as major components with presence of magnesium carbonate and traces of hydromagnesite. Magnesite and hydromagnesite do not develop within the normal carbonation processes suggesting that magnesium carbonate was intentionally employed for improving the material characteristics

EVALUATION OF ECO-COMPATIBLE METHODOLOGIES TO CLEAN STONE SURFACES POLLUTED BY OIL SPILL

This research concerns the structuring of a suitable method for the removal of oil (Fuel Oil 120 cSt) from traditional bricks and Istrian Stone, materials commonly found amongst embankments and buildings of North Adriatic coastal cities. A cleaning protocol, based upon non-toxic products, was developed in consideration of its compatibility with historical, architectural surfaces. The contamination effects of oil on Istrian stone and fired clay bricks was studied, followed by a range of cleaning treatments using bulk sorbents, surfactant solutions and N, N-dimethyl-octanamide. The application was executed using the products singularly, combined or in succession. The succession of sorbent, solvent and surfactant solution demonstrated good capability of removal and was then applied on macrosamples of brick masonry showing good results

Evaluation of Eco-compatible methodologies to clean stone surfaces polluted by oil spill

Accidental oil spill is a serious hazard for marine ecosystem and several protocols have been developed to guarantee eco-sustainable intervention concerning sea, marine fauna and shores [1]. Architectural surfaces of historical building close to the sea might also be polluted by oil spill, with further complication due to tidal excursion, but any general rules of interventions have been developed to safeguard them and the restorers’ health. The past practices based on the use of toxic solvent (e.g. toluene and other organic solvents) are not admissible anymore [1-3], but the effectiveness of more eco-compatible methods on architectural surfaces is not well known yet. This research deals with the set up of suitable methods for the removal of oil (Fuel Oil 120 cSt) from traditional bricks and Istria Stone, materials commonly found in the embankments and buildings of North Adriatic coastal cities. The use of organic solvents have been compared to methods having lower toxicity for restorers and the environment, and low dispersion (e.g. by using poulticing) [5]. Brick and Istria stone specimens were put in contact with fuel oil for different time laps; the pollution effects and the oil penetration profiles were assessed by SEM-EDX, FT-IR spectroscopy and colorimetric evaluations. Different media (cellulose-based media, bentonite), solvents (N,N-dimetylottanammide, toluene only as comparison solvent), solid adsorbents (absorbent from Sphagnum Peat Moss, Ecosorboil) and non ionic surfactants have been tested in removing the oil from the polluted specimens, both alone (by brushing the surfaces) and in combination (by poulticing). The results indicate that oil is not able to penetrate Istria stone, but it impregnates bricks for around 2 mm depth. Among the ones tested ,the most effective methodology implies brushing the absorbent from Sphagnum Peat Moss on the surface to eliminate oil excess, followed by application of N,Ndimetylottanammide mixed with a surfactant agent. The removal is not complete for bricks, but the reduction of the amount of oil and the breaking of long hydrocarbon chains accelerates the natural decomposition

The study of pitch via gas chromatography-mass spectrometry and Fourier-transformed infrared spectroscopy: The case of the Roman amphoras from Monte Poro, Calabria (Italy)

The analysis of the composition of organic residues present in ancient pottery are an important source of information for archaeologists. The chemical characterisation of these materials gives information on diets, habits, technologies and original use of the vessels. In this paper the resinous materials from the interior surfaces of Roman amphoras and the contents of two particular vessels (called Kadoi) coming from Monte Poro, in Calabria (Italy) were studied. The organic materials were identified by Fourier-transformed infrared spectroscopy (FT-IR) and gas chromatography coupled with mass spectrometry (GC–MS). The presence of monocarboxylic acids and terpenic species shows that the organic residues were of vegetable origin or mainly consist of vegetable-based resins. Moreover, the presence of characteristic diterpenic biomarkers permits to recognize the use of pine resin and pine pitch, while the presence of methyl dehydro-abietic acid is likely linked to the use of wood tar and not only to the pine pitch. It was not possible to identify with accuracy the species of Pine used to prepare the pitch since the profile of diterpenoid acids of an aged and thermal treated resin is very different from the one of fresh resin. Nevertheless, the hypothesis about the use of Pinus Laricius and Pinus Negrus to prepare the pitch is plausible as these two species were and are both very abundant in Monte Poro's area

An exploration of scaffolding in relation to gestures and code switching : a case study of a private university, Thailand

This study reports on how five Thai teachers in a private university scaffold their students in an EFL classroom in relation to gestures and code switching. The context of this study is described as teacher-fronted instruction and focuses on low proficiency students. Using the qualitative-based method of a case study, observation is a principal data collection tool. Interview and field notes are employed to supplement the data. The study reveals basic types of instructional activities: focus on form and focus on meaning from the observational data. Scaffolding is first explored using frameworks adopted from Wood et al (1976) and van Lier (1996). The findings illuminate that the verbal interaction of Thai teachers with their students reflects scaffolding features described by Wood et al (1976) while slightly reflecting what van Lier (1996) describes as attributes. The exploration includes gestures as they naturally accompany verbal communication (Harris, 2005). Additionally, code switching to Thai is also investigated as Thai is the mother tongue of the teachers and the students. Gestures are found accompanying scaffolding features and related strategies. Three gestures are identified in this study. Illustrative gestures are found to be the most common, followed by regulative and emotional gestures. The study concludes by summarising the features of scaffolding in the teacher-fronted style of teaching. This embraces all the findings in relation to form- and meaning-focused activities. Scaffolding in the form-focused activities illuminates long sequentiality, less gestures, long utterances of code switching to 1 Thai, less contingency, and contextual support, while scaffolding in the meaning-focused activities consist of short sequentiality, more gestures, short utterances of code switching, more contingency, and contextual support. More and less effective scaffolding strategies are also proposed regarding to what extent they can promote the learners' engagement. The study offers the EFL teachers dealing with low proficiency learners and teacher-fronted instruction the pedagogical implications for gaining the learners' engagement by focusing on employing gestures and code switching. It also suggests that scaffolding is a practical technique which should be promoted in pedagogical training.EThOS - Electronic Theses Online ServiceGBUnited Kingdo