Abstract: The subject of the invention is method and device system for entering and retrieving information in the surface layer of objects made of solid matters. The information is entered with a (concentrated) beam directed to the surface and having a power density selected to induce permanent change at least in the surface layer of the material's structure in a way that the power density of the beam is smaller that the power density of the beam causing visible deformation, but bigger than that of the beam that causes (within the order of magnitude of the beam's diameter) inhomogeneities commensurable with the structural inhomogeneities generally present in the material. The invention can be used for all materials, the structure or internal stress of which can be modified with high energy density surface treatment (at the location of the treatment) (specially with the local laser treatment of ferromagnetic material).

Abstract: A method for determining the longitudinal loading acting on a beam, such as a rail of a railway track subjected to longitudinal loading and, in particular, for determining the neutral temperature of railway tracks. The beam is energized longitudinally in the acoustic frequency range, and the level of magnetic Barkhausen noise at the surface of the energized region is measured. Measurements of the magnetic Barkhausen noise are taken for different longitudinal stress states and used for plotting the calibration curve of the magnetic Barkhausen noise as a function of longitudinal stress, the Barkhausen noise being measured at least at three points on the face of the built-in beam, and the calibration curve is used for determining the longitudinal loading on the cross-section in question using weighted averaging. The neutral temperature of the railway track is then calculated considering the modulus of elasticity, coefficient of thermal expansion and temperature of the rail.