Showing papers by "Domenica Paoletti published in 2012"

NDT inspection of plastered mosaics by means of transient thermography and holographic interferometry

Abstract: In this research work, experimental procedures by means of Transient Thermography and Holographic Interferometry were performed in order to detect subsurface tesserae areas of plastered mosaics. A mosaic sample consisted of various types of tesserae and covered with hydraulic lime mortar was evaluated in the laboratory with various transient thermal processing techniques such as Pulsed Phase Thermography, Thermographic Signal Reconstruction and Principal Component Thermography, as well as Holographic Interferometry in both real-time and double-exposure configurations. Results from the non-invasive investigation are presented and discussed, revealing that the above approaches can obtain a seeing through investigation of plastered mosaics.

Thermal quasi-reflectography: a new imaging tool in art conservation

Abstract: In the artwork conservation field, non contact diagnostic and imaging methods are widely used and most welcomed. In this work a new imaging tool, called Thermal Quasi-Reflectography (TQR), is proposed and demonstrated. It is based on the recording, by suitable procedures, of reflected infrared radiation in the MWIR band (3-5 μm). The technique, simple to perform, can provide very interesting results in the analysis of the painting surfaces. TQR was demonstrated in situ on two famous artworks: the Zavattari's frescos in the Chapel of Theodelinda (Italy) and the masterpiece by Piero della Francesca "The Resurrection" (Italy).

Evaluation of defects in panel paintings using infrared, optical and ultrasonic techniques

Abstract: The increasing deterioration of panel paintings can be due to physical processes that take place during exhibition or transit, or as a result of temperature and humidity fluctuations within a building, church or museum. In response to environmental alterations, a panel painting can expand or contract and a new equilibrium state is eventually reached. These adjustments though, are usually accompanied by a change in shape in order to accommodate to the new conditions. In this work, a holographic method for detecting detached regions and micro-cracks is described. Some of these defects are confirmed by Thermographic Signal Reconstruction (TSR) technique. In addition, Pulsed Phase Thermography (PPT) and Principal Component Thermography (PCT) allow to identify with greater contrast two artificial defects in Mylar which are crucial to understand the topic of interest: the discrimination between defect materials. Finally, traditional contact ultrasounds applications, are widely applied for the evaluation of the wood quality in several characterization procedures. Inspecting the specimen from the front side, the natural and artificial defects of the specimen are confirmed. Experimental results derived by the application of the integrated methods on an Italian panel painting reproduction, called The Angel specimen, are presented. The main advantages that these techniques can offer to the conservation and restoration of artworks are emphasized.

From the experimental simulation to integrated non-destructive analysis by means of optical and infrared techniques: results compared

Abstract: In this work the possibility of modeling manufacturing ceramic products is analyzed through the application of transient thermography, holographic interferometry and digital speckle photography, in order to identify the subsurface defects characteristics. This integrated method could be used to understand the nature of heterogeneous materials (such as plastic, sponge simulating a void, wood, aluminum) potentially contained within ceramic materials, as well as to predict crack formation due to them. The paper presents the analysis of green ceramic tile containing defects of different types and sizes located at different depths. The finite element method is used for solving the problem of transient heat transfer occurring in experimental conditions. Unknown parameters of the numerical model (such as convective heat transfer coefficients and sample surface emissivity) were adjusted to obtain numerical simulation results as close as possible to those obtained experimentally. Similarities and differences between experimental and simulated data are analyzed and discussed. Possibilities for improving the results and further developments are proposed.