Aircraft clouds: from chemtrail pseudoscience to the science of contrails

The most frequent statements and arguments found in pseudoscience websites and forums supporting the existence of so-called aircraft chemtrails can be refuted with a scientific explanation of the processes resulting in the formation of condensation or deposition trails, known as contrails. Thus, the hypothesis that chemtrails exist is disproven by the scientific literature that shows that they are the exact same entity as contrails: They are hydrological phenomena which result from a physical process referenced in the many studies carried out since the beginning of the age of aviation, in the early twentieth century. Hence, in this paper we conclude that pseudoscience’s chemtrails are nothing more than the contrails described by science.Peer ReviewedVersió final publicad

Development of a Low-Cost Weather Station to Measure in Situ Essential Climate Variables

A weather station is proposed especially designed for developing countries, and to meet the standards of the international scientific community making research on the earth system. The station would measure in situ several ECV (essential climate variables). These data may enable an agricultural breakthrough in countries lacking meteorological infrastructure, help in climate change monitoring, and facilitate diffusion of wind energy. A pre-feasibility analysis is presented. It appears interesting that the station is supplied by a social enterprise. A research to establish the best shelter design using computational fluid dynamics is also reported. The criterion is the accuracy with which the surface air temperature is reproduced inside the shelter. A design following recommendations by the WMO (World Meteorological Organization), a smaller design with identical geometry, and two alternative small designs are analyzed. All four designs are simulated in PVC, natural rubber and wood, with and without white paint coating. The smaller shelters perform better. The influence of the material, dimensions and design is smaller than that of the white paint. Shelters made of PVC or rubber, and/or in alternative designs, may be more interesting if other criteria are considered, like whether logistics, manufacturing, etc. are more sustainable, easier and/or cheaper.Peer ReviewedPostprint (published version

The potential of the sea breeze for wind energy generation in peri-urban coastal areas using small wind turbines

This work investigates the potential of the sea breeze for wind energy generation with small wind turbines. For this purpose, we used wind data recorded in the Llobregat Delta (NE of the Iberian Peninsula) from 1993 to 2010 and turbine power curves obtained from QBlade, FAST and AeroDyn freeware tools, and from the manufacturer. The HP-600W turbine, with hub-height 8 m, would deliver 126 kWh in a year (53 kWh during the sea breeze period, i.e., March 1 to September 30, 10 to 19h LT), with average power of 14 W (27 W). The results for the entire year agree with data measured in situ in 2015, but it is not the case for the sea breeze period. Therefore, more research is necessary to validate completely the proposed approach, and to confirm the real potential of the sea breeze for micro-generation in a peri-urban coastal area like the one under study, where large wind farms are not feasible.Peer ReviewedPostprint (author's final draft

Meteoròlegs amb cara i ulls: exposició de meteoròlegs catalans de tots els temps

The Catalan meteorology has contributed in an important way to the international development of this science along the history. Some of the studious Catalan scientists of the atmosphere are very known, like Eduard Fontserè, but other, in spite of the important developed task they have remained, for diverse motives, forgotten, or do not know themselves well. Introducing the contribution and the figure of the main meteorologists of our country it has been the main goal of the Associació Catalana d’Observadors Meteorològics (ACOM) to promote in year 2006 the recovery and divulging of these characters, while carrying out some small sculptures of theirs bust, making expensive to this scientists

Inactivación bacteriana y vírica durante la regeneración de agua

El pricipal objetivo de esta tesina ha sido evaluar la capacidad del proceso de regeneración de agua para inactivar bacterias y virus, hasta niveles de calidad comparables con los establecidos en el Código del Agua del estado de California (Titulo 22). El estudio se realizó en la planta de regeneración de agua instalada en la EDAR de Mataró. La desinfección con cloro consigue que más del 85% de las muestras analizadas cumplan con los criterios de calidad en cuanto a la ausencia de CT/100ml. En cambio, la desinfección con luz UV e hipoclorito sólo consigue que un 10% de las muestras cumplan con el nivel de desinfección recomendado para riego de productos de consumo crud

Las responsabilidades del profesor en la dirección de los trabajos de fin de grado

Este artículo reflexiona sobre las responsabilidades del profesor durante el proceso de elaboración, presentación oral y evaluación de un Trabajo de Fin de Grado. A falta de indicadores normativos, se considera que son dos las variables que deben definir estas responsabilidades: el sentido de esta asignatura como colofón del proceso formativo de Grado; y las necesidades o debilidades de los estudiantes que se encuentran al final de este ciclo universitario. A partir de estos dos parámetros, el artículo desmenuza las muy diversas y complejas tareas del docente y concluye con un apartado que pretende ofrecer soluciones al escaso tiempo dedicado a esta asignatura y al delicado equilibrio entre la pro-actividad del profesor y la iniciativa del estudiante.This article reflects ontheresponsibilities of the teacher during the elaboration, the oral presentation and the evaluation of a Final Project. Given the lack ofregulatory indicators, it is considered that there are two variables that sould define these responsibilities: the sense of this subject as the culmination of the Grade training process; and the weak nesses and need sof the students who are at the end of this academic cycle. Given these two parameters, the article scrutinize the very diverse and complex tasks of the teacher and concludes with a section that aims to provide solutions to the limited time devoted to this subject and to the delicate balance between the proactivity of the teacher and the student initiative