title: Functional Analysis in Long-Term Operation of High Power UV-LEDs in Continuous Fluoro-Sensing Systems for Hydrocarbon Pollution.
abstract: This work analyzes the long-term functionality of HP (High-power) UV-LEDs (Ultraviolet Light Emitting Diodes) as the exciting light source in non-contact, continuous 24/7 real-time fluoro-sensing pollutant identification in inland water. Fluorescence is an effective alternative in the detection and identification of hydrocarbons. The HP UV-LEDs are more advantageous than classical light sources (xenon and mercury lamps) and helps in the development of a low cost, non-contact, and compact system for continuous real-time fieldwork. This work analyzes the wavelength, output optical power, and the effects of viscosity, temperature of the water pollutants, and the functional consistency for long-term HP UV-LED working operation. To accomplish the latter, an analysis of the influence of two types 365 nm HP UV-LEDs degradation under two continuous real-system working mode conditions was done, by temperature Accelerated Life Tests (ALTs). These tests estimate the mean life under continuous working conditions of 6200 h and for cycled working conditions (30 s ON &amp; 30 s OFF) of 66,000 h, over 7 years of 24/7 operating life of hydrocarbon pollution monitoring. In addition, the durability in the face of the internal and external parameter system variations is evaluated.
authors.affiliation: ETSIST-Technical University of Madrid, Madrid 28031, Spain. jose.arques@upm.es.
authors.forename: Francisco Jose
authors.initials: FJ
authors.lastname: Arques-Orobon
authors.affiliation: ETSIST-Technical University of Madrid, Madrid 28031, Spain. neftali.nunez@upm.es.|Instituto de Energía Solar-Technical University of Madrid, Madrid 28040, Spain. neftali.nunez@upm.es.
authors.forename: Neftali
authors.initials: N
authors.lastname: Nuñez
authors.affiliation: ETSIST-Technical University of Madrid, Madrid 28031, Spain. manuel.vazquez@upm.es.|Instituto de Energía Solar-Technical University of Madrid, Madrid 28040, Spain. manuel.vazquez@upm.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Vazquez
authors.affiliation: ETSIST-Technical University of Madrid, Madrid 28031, Spain. vgonzalz@diac.upm.es.
authors.forename: Vicente
authors.initials: V
authors.lastname: Gonzalez-Posadas
mesh_terms: D006801:Humans; D006838:Hydrocarbons / Q000302:isolation & purification*; D014466:Ultraviolet Rays; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D006838:Hydrocarbons; D014874:Water Pollutants, Chemical; D014867:Water
keywords: UV-LED sensing; continuous real-time sensing; fluorescence spectroscopy; pollution identification; water pollution