In this paper, a precise real-time temperature control system based on infrared (IR) thermometry for domestic induction cooking is presented. The temperature in the vessel constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooker. A proportional-integral controller is applied to establish the output power level in order to reach the target temperature. An optical system and a signal conditioning circuit have been implemented. For the signal processing a microprocessor with 12-bit ADC and a sampling rate of 1 Ksps has been used. The analysis of the contributions to the infrared radiation permits the definition of a procedure to estimate the temperature of the vessel with a maximum temperature error of 5 °C in the range between 60 and 250 °C for a known cookware emissivity. A simple and necessary calibration procedure with a black-body sample is presented.
The use of frequency selective surfaces (FSSs) defined on railcar windows with a metallic low-e coating to improve the reception of mobile communications signals is becoming ever more common. The proximity of the glass to the passenger in this scenario has introduced a new parameter to consider, aesthetics. This paper presents a complete study of the development of a FSS defined by laser ablation, considering all current requirements. The fabricated samples will be characterized in the optical and radiofrequency ranges of the spectrum. Also, by means of an electron microscope, the chemical elements of each area of the samples will be quantified, in order to study the ablation process. New samples will be made using these parameters, and its performance according to specifications verified. These data will be correlated, using digital image processing, to the aesthetic impact of the engraved FSS, as confirmation of the optimal laser configuration.
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