THERMODYNAMICS FOR CULTURAL HERITAGE PhD student: Maria Concetta Di Tuccio Supervisor: Dr. Nicola Ludwig University of Milan Assistant Supervisor: Dr. Adriana Bernardi ISAC- CNR, Padua Milan - 15 th October 2012

Development points MAIN OBJECTIVE: to deepen the measurement methodology of the surface temperature of the works of art with remote sensing  Evaluation of the problems related to the measure of surface temperature by mean of remote traditional tecniques: radiometer and thermocamera  Test of the working of the new sensor:  calibration in climatic chamber and thermal bath;  evaluation of the influence of the sensor self-heating;  determination of the best measuring conditions (distance from the surface to be monitored).  Evaluation of the risk of damage related to thermo-hygrometric stress on different materials, particularly wood and plaster  Field tests: S. Croce Museum, Florence

Why the monitoring of the surface temperature is important? The surface temperature is strongly influenced by the environment The materials are subjected to changing microclimatic conditions Evaporation processes PLASTER Salts cristallization Detachment and loss WOOD Thermal gradients EMC variation Dimensional variations Cracks, detachment of paint layer

Contact sensor Quasi-contact sensor Drawback: The sensor need to be in contact with the surface → difficult to realize Not usable for distant and/or untouchable surfaces Advantages: There is not the problem of the emissivity Measuring the surface temperature in Cultural Heritage

Radiometer Remote sensing Thermocamera The measures are strongly influenced by the reflected radiation radiometerthermocamera Spot monitoringContinuous monitoring Accurate measurement : setting of the E in each point of the surface Less accurate measurement : setting of the same E in the area investigated

Radiometric measures S.Croce Museum - Firenze Deposizione della Croce of Francesco Salviati T(°C) T(C°)

Calibration of the new sensor climatic chamber Thermal bath More stable More precise calibration Calibration in real condition Temperature of the black body immersed in the thermal bath: 10°C – 20 °C – 30 °C – 40°C – 50 °C Temperature of the black body: 10°C 20°C - 30°C 40°C - 50°C Temperature of climatic chamber: 10°C - 20°C 30°C - 40°C 50°C

Insulation materials Black body at variable temperature for calibration in climatic chamber Reflective material Pt100 at the bottom

Monitoring of the black body Tm: 37,7 °C Pt100 temperature: 37,6 °C Tm: 40,3 °C Pt100 temperature: 40,2 °C

Tm: 45,8°C Pt100 temperature: 45,9 °C Tm: 50,05 °C Pt100 temperature: 50,3 °C Monitoring of the black body

Work plan for the near future Validation of the new instrument  To separate the electronic part and the sensor  To calibrate in the climatic chamber and in thermal bath  To evaluate the influence of the self-heating of the sensor on the measures  To determine the best distance between the sensor and the surface