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Due to the increasing need for continuous use of face masks caused by COVID-19, it is essential to evaluate the filtration quality that each face mask provides. In this research, an estimation method based on thermal image processing was developed; the main objective was to evaluate the effectiveness of different face masks while being used during breathing. For the acquisition of heat distribution images, a thermographic imaging system was built; moreover, a deep learning model detected the leakage percentage of each face mask with a mAP of 0.9345, recall of 0.842 and F1-score of 0.82. The results obtained from this research revealed that the filtration effectiveness depended on heat loss through the manufacturing material; the proposed estimation method is simple, fast, and can be replicated and operated by people who are not experts in the computer field. [ABSTRACT FROM AUTHOR]

This paper presents the design of a fault detection and diagnosis system for a quadrotor unmanned aerial vehicle under partial or total actuator fault. In order to control the quadrotor, the dynamic system is divided in two subsystems driven by the translational and the rotational dynamics, where the rotational subsystem is based on a linear parameter-varying model. A robust linear parameter-varying observer applied to the rotational subsystem is considered to detect actuator faults, which can occur as total failures (loss of a propeller or a motor) or partial faults (degradation). Furthermore, fault diagnosis is done by analyzing the displacements of the roll and pitch angles. Numerical experiments are carried out in order to illustrate the effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

We propose new instrumentation to measure the refractive index (RI) of transparent liquids as a function of temperature. The physical phenomenon used to carry out the measurement is the light refraction that occurs in transparent liquids. A width change in a reference object is produced by light refraction, which is related to the RI. Image processing was used to measure the object width using an image from a digital microscope. The instrument measures the RI from a range of 15°C to 100°C with an accuracy of 10 − 4 %. The measurement procedure was calibrated with distilled water and acetonitrile samples, and the Sellmeier and Cauchy equation was used to compare our results. Finally, as an appropriate application, the RI of lophine in a solution was measured. [ABSTRACT FROM AUTHOR]