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A. Tagliani

Publications and source records attributed to A. Tagliani.

2 recordsLinked to original sources

Statistical properties of acoustic emission signals from metal cutting processes

Acoustic Emission (AE) data from single point turning machining are analysed in this paper in order to gain a greater insight of the signal statistical properties for Tool Condition Monitoring (TCM) applications. A statistical analysis of the time series data amplitude and root mean square (RMS) value at various tool wear levels are performed, �nding that ageing features can be revealed in all cases from the observed experimental histograms. In particular, AE data amplitudes are shown to be distributed with a power-law behaviour above a cross-over value. An analytic model for the RMS values probability density function (pdf) is obtained resorting to the Jaynes' maximum entropy principle (MEp); novel technique of constraining the modelling function under few fractional moments, instead of a greater amount of ordinary moments, leads to well-tailored functions for experimental histograms.

physics.data-an

The magnetic field in the Coma cluster

The polarization data of the radio galaxy NGC4869, belonging to the Coma cluster and located in its central region, allow us to obtain information on the structure of magnetic field associated with the cluster itself. A magnetic field of $\sim$ 8.5 $μ$G, tangled on scales of the order of less than 1 kpc, is required to explain the observed fluctuations of the rotation measure. This magnetic field is more than one order of magnitude stronger than the equipartition value obtained for Coma C. This implies that the halo source Coma C may not be at the equipartition. Moreover, the need of efficient reacceleration mechanisms for the electrons radiating in Coma C is stronger. The energy supply to the Coma C radiating electrons is probably provided by the cluster merger process.

astro-ph