GNGTS 2013 - Atti del 32° Convegno Nazionale

Conclusions. The aim of this work was to find a useful technique in order to construct a European model of the main and crustal magnetic fields from real geomagnetic satellite data. Here, we analyzed different sets of magnetic data, first a set of synthetic data from CM4 global model in order to validate the analysis procedure, and then a real satellite data set covering a period from 1999 to 2005. The regional model we present here shows a clear agreement with other global models like CM4 and CHAOS-4, but presents more details in terms of the spatial wavelength. We found that both the datasets allow us to model very well the crustal field, at 450 km height when comparing with the global CHAOS-4 model in the European region. Also, a level-to-level upward continuation to 450 km of the CM4 data at ground level works reasonably well, proving the efficiency of present level-to-level techniques in a satellite-altitude framework. References de Boor, C. 2001. A Practical Guide to Splines. Springer, New York, p. 368. Gubbins, D., and Bloxham J. 1985. Geomagnetic field analysis - III. Magnetic fields on the core-mantle boundary, Geophysical Journal of the Royal Astronomical Society 80, 695-713. Haines, G. V. 1985. Spherical cap harmonic analysis, Journal of Geophysical Research, 90 (B3), 258-2591. Korte, M., and Holme, R. 2003. Regularization of spherical cap harmonics, Geophysical Journal International 153, 253– 262. Matzka, J., Chulliat, A., Mandea, M., Finlay, C., Qamili, E., 2010. Geomagnetic Observations for Main Field Studies: from Ground to Space. Space Science Reviews 155 (1-4), 29-64. Olsen, N., Luehr, H., Sabaka, T. J., Michaelis, I., Rauberg, J., Tøffner-Clausen, L. 2010. CHAOS-4: A high-resolution geomagnetic field model derived from low-altitude CHAMP data, AGU Fall Meeting. Sabaka, T.J., Olsen, N., and Purucker, M.E. 2004. Extending comprehensive models of the Earth’s magnetic field with Ørsted and CHAMP data. Geophysical Journal International 159, 521–547, 2004. A PRELIMINARY TESTON THE FEASIBILITYOF LOCATINGAN IRONRESTORATION PIN IN A STATUE BY MEASURING THE TMF ANOMALY WITH A TRIAXIAL MEMS MAGNETOMETER L. Sambuelli 1 , S. Gallinaro 2 , M. Grosso 2 1 Diati – Politecnico Di Torino, Italy 2 St-Polito S.c.ar.l., Italy Foreword. Non-Destructive Testing (NDT) techniques have gained a growing role in Cultural Heritage Conservation. In the last years many scientists and technicians have been testing this increasing role (e.g. Livingston, 2001; Grimberg, 2009; Binda and Siasi, 2009). Recently (Cosentino et al. , 2011) the faint border between NDT and Geophysics has been “officially” broken in consideration of the large overlap of the methodologies used in both the disciplines. With respect to the testing of art artefact such as statues or architectural fragments four types of physical methods are available: sound (mechanical waves), penetrating radiation (X-ray, γ-rays), light (visible, near-visible), electromagnetic (magnetic, electrical impedance, electromagnetic induction, radar). A particular application of the NDT technique is the location of iron or steel reinforcements or pins. Many times the purpose of the NDT inspection is to find out not only the presence but also the size and the position of the metal pins to understand if they can properly perform their structural function. Ancient iron pins instead of having a reinforcement function can sometimes contribute to the failure of the restoration work (Jain et al. , 1988). This negative effect can derive from different causes: because of rust and/or a wrong positioning of the pins. When the iron rusts the consequent expansion of the oxides generates stresses within the stone and cracks can occur. Sometimes the pins have not been placed in the centre of the volume 169 GNGTS 2013 S essione 3.2