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Thermomechanical characterization of the dissipation fields around microscale inclusions in elastomers
Published in Alexander Lion, Michael Johlitz, Constitutive Models for Rubber X, 2017
T. Glanowski, Y. Marco, V. Le Saux, B. Huneau, C. Champy, P. Charrier
The temperature resolution of an infrared camera is given by the Noise Equivalent Temperature Difference (NETD), which quantifies its thermal sensitivity. The NETD is evaluated from the fluctuations of the measured temperatures while starring a temperature stabilized scene. The frequency distribution of the measured temperatures can be approximated by a standard normal distribution (Vollmer M. and Möllmann K. 2010): () f(x)=Aσ2πe−(x−μ)22σ2
Strain energy evolution analysis of elastic-plastic deformation on polycarbonate by infrared radiation characteristics
Published in Nondestructive Testing and Evaluation, 2023
Lu Chen, Dejian Li, Mingyuan Zhang, Muao Shen, Junhao Huo, Yingjun Li
To eliminate the influence of environmental interference, an isolating box with 2 m in length, 0.5 m in width and 0.5 m in height to surround the sample and loading instrument. The isolating box is made of cystosepiment to decrease the thermal exchange between the sample and surroundings. To better understand the thermodynamic characteristics of polycarbonate, tensile tests were carried out on the polycarbonate at room temperature during four different loading rates: 4 mm/min, 6 mm/min, 8 mm/min and 10 mm/min. The infrared thermography was used to synchronously capture the infrared radiation distribution of the sample. The specifications of infrared thermography are show as follows: resolution, 640 × 512 pixels; noise-equivalent temperature difference, 0.05 K, frame rate, 8 fps; spectral range, 7.5–14 μm. The infrared thermography was placed 0.5 m away from the sample and turned on one hour in advance for preheating before loading. The polycarbonate was stretched to 40 mm at different loading rates to produce significant plastic deformation, and the infrared radiation and mechanical parameters were obtained simultaneously.
Electrothermal analysis of a TEC-less IR microbolometer detector including self-heating and thermal drift
Published in Quantitative InfraRed Thermography Journal, 2023
M. Felczak, T. Sosnowski, R. Strąkowski, G. Bieszczad, S. Gogler, J. Stępień, B. Więcek
On the other hand, the high-frequency part of the Nyquist plot allows estimation of the variation of the microbolometer temperature due to the scanning and reading process of the entire FPA at a given frame-rate (f = 30 Hz in the presented research). Using the thermal impedance in the frequency domain, it is quite easy to determine the RMS value of the temperature generated in a microbolometer by self-heating. Figure 10 shows the thermal impedance in the high frequency range. Real and imaginary parts of the thermal impedance are still very high for f = 30 Hz. It implies the high value of magnitude of Zth. The power generated periodically in the microbolometer may cause additional temperature fluctuations. This can degrade one of the most important metrological parameters of a bolometer camera – the Noise Equivalent Temperature Difference (NETD).
Assessing the effective penetration depth of mid-wave infrared radiation in water for fluid dynamic measurements
Published in Quantitative InfraRed Thermography Journal, 2023
The thermal radiation from the cuvette was captured by an infrared camera FLIR SC7700 operating in the 3.7–4.8 µm spectral range (mid-wave infrared). The camera was equipped with a cooled focal-plane-array MCT (Mercury-Cadmium-Telluride) photon detector of 640 × 512 pixels with a temperature sensitivity (noise equivalent temperature difference or NETD) specified by the manufacturer of 18 mK at 25C. The camera was placed 30 cm from the wedge. Each snapshot of the wedge was captured with the spatial resolution of 6 px/mm using a 50-mm lens. To avoid the narcissus effect (i.e. the thermal sensor observing its own reflection), the camera was positioned slightly off-centre from the cuvette (but at an angle small enough not to increase the measurement error [28]). During the measurements, the infrared camera was focused on the outer surface of the cuvette.