Jorunal: Óptica Pura y Aplicada

Paper: Análisis LIBS de doce estatuillas de bronce expuestas en el Museo Arqueológico Nacional de Crotona

AUTHORS:A. Foresta, F. Anabitarte García, S. Legnaioli, G. Lorenzetti, D. Diaz Pace, L. Pardini, V. Palleschi

Abstract: En el transcurso de la colaboración entre el Departamento de Química y Química Industrial de la Universidad y el Consejo Nacional de Investigación (CNR Consiglio Nazionale delle Ricerche), ambos en Pisa, ha sido posible analizar científicamente diferentes muestras arqueológicas. En este caso se han seleccionado doce pequeñas estatuas de bronce expuestas en el Museo Arqueológico Nacional de Crotona, que fueron previamente estudiadas, con el objetivo final de profundizar aun más en el conocimiento de estas muestras. En el Museo Arqueológico Nacional de Crotona, fue llevado a cabo el análisis de las doce muestras de bronce basado en técnicas espectroscópicas, concretamente LIBS acrónimo de Laser Induced Breakdown Spectroscopy), empleando el MODI (Mobile Dual‐pulse Instrument, o Instrumento Móvil de Doble Pulso) para analizar las muestras in situ. Las muestras obtenidas fueron analizadas cualitativamente y cuantitativamente, para discernir las características químicas de las muestras de bronce. El objetivo del análisis es encontrar marcadores o elementos químicos que permitan distinguir unas muestras de otras por ser importantes en la composición del metal que compone las estatuillas.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy

Paper:  X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy analysis of Roman silver denarii

AUTHORS: L. Pardini, A. El Hassan, M. Ferretti, A. Foresta, S. Legnaioli, G. G. Lorenzetti, E. Nebbia, F. Catalli, M.A. Harith, D. Diaz Pace, F. Anabitarte Garcia, M. Scuotto, V. Palleschi  

Abstract:  In this paper we present the results of a study performed on a large collection of silver Roman republican denarii, encompassing about two centuries of history. The joint use of Laser-Induced Breakdown Spectroscopy (LIBS) and X-Ray Fluorescence (XRF) spectroscopy allowed for an accurate determination of the coins' elemental composition; the measurements, performed mostly in situ at the ‘Monetiere’ in Florence, revealed a striking connection between the ‘quality’ of the silver alloy and some crucial contemporary events. This finding was used to classify a group of denarii whose dating was otherwise impossible. The comparison with other contemporary denarii disproves a recent theory on the origin of the so called ‘serrated’ denarii (denarii showing notched chisel marks on the edge of the coin).

Journal: Journal of Sensors

Paper: Welding diagnostics by means of particle swarm optimization and feature selection  

AUTHORS: J Mirapeix, P B García-Allende, O M Conde, J M Lopez-Higuera and A Cobo 

Abstract: In a previous contribution, a welding diagnostics approach based on plasma optical spectroscopy was presented. It consisted of the employment of optimization algorithms and synthetic spectra to obtain the participation profiles of the species participating in the plasma. A modification of the model is discussed here: on the one hand the controlled random search algorithm has been substituted by a particle swarm optimization implementation. On the other hand a feature selection stage has been included to determine those spectral windows where the optimization process will take place. Both experimental and field tests will be shown to illustrate the performance of the solution that improves the results of the previous work. 

Journal: IEEE Sensors Journal

Paper: Sensor system based on a Brillouin fiber laser for remote in series fiber Bragg gratings interrogation  

AUTHORS: A. Ullan, M.A. Quintela, L. Rodriguez-Cobo, A. Quintela y J.M. Lopez-Higuera 

Abstract: A simple sensor system designed to monitor the temperature or strain of a certain number of critical points along a structure is presented and demonstrated. It is based on the remote interrogation of fiber Bragg gratings placed in series by means of a Brillouin fiber laser. Three FBGs were interrogated at 50 km away from the processing unit using 8 mW of Brillouin pump. Heterodyne detection brings forth a signal to noise ratio of approximately 40 dB in our measurements.