Cooling-down of thermal thick probes after flash excitation – A measure for the real energy density?

Determination of Thermal Parameters of Concrete by Active Thermographic Measurements

“…A successful application of Eq. 5 was reported in [27] demonstrating the power of this simple relationship.…”

“…The real energy absorption plays a major role in active thermography because it influences the achieved temperature increase directly and a useful discussion of thermal effects is almost impossible without this number (see [26] and references therein). Since it is known that concrete can have a noticeable reflectance [27] the reflectivity was measured with a spectrometer, the Perkin-Elmer Lambda 1050 s. The wavelength range was limited to the range between 930 and 950 nm, including the wavelength of the laser used as heating source (see Sect. 4).…”

“…In a simple model with spatially homogeneous Dirac pulse heating of an opaque and isotropic material, where the heat is completely absorbed at the surface, and where all heat losses and a finite sample thickness are completely neglected, the surface temperature-time dependence T(t) can be described by the following equation [27,29]:…”

Applying a Two-Layer Quadrupole Model for Quantitative Thermography at Overload-Induced Delaminations in GFRP

“…The irradiated energy of the flash lamps at the surface of the specimens was measured using a PVCplate, as described in Ref. [10], it reached 8.0 kJ m ⁄ . The surface-temperature of the GFRP-plate was recorded for 2500 s at a frame rate of 10 Hz by a MWIR-camera (InfraTec ImageIR 8300), at a NETD of 25 mK.…”