Brewer-OMI comparison for El Arenosillo 2015 campaign

Presentación realizada en: Work Group meeting of the COST action 1207 EUBREWNET, celebrada en Sodankylä, Finlandia del 11 al 12 de noviembre de 2015

Long-Term Analysis of Aerosol Concentrations Using a Low-Cost Sensor: Monitoring African Dust Outbreaks in a Suburban Environment in the Canary Islands

This study presents the results of the long-term monitoring of PM10 and PM2.5 concentrations using a low-cost particle sensor installed in a suburban environment in the Canary Islands. A laser-scattering Nova Fitness SDS011 sensor was operated continuously for approximately three and a half years, which is longer than most other studies using this type of sensor. The impact of African dust outbreaks on the aerosol concentrations was assessed, showing a significant increase in both PM10 and PM2.5 concentrations during the outbreaks. Additionally, a good correlation was found with a nearby reference instrument of the air quality network of the Canary Islands’ government. The correlation between the PM10 and PM2.5 concentrations, the effect of relative humidity, and the stability of the sensor were also investigated. This study highlights the potential of this kind of sensor for long-term air quality monitoring with a view to developing extensive and dense low-cost air quality networks that are complementary to official air quality networks

El principio de facilitación de comercio y la gestión de riesgo aplicado por la administración aduanera en el despacho de importación para consumo, 2018

El presente trabajo de investigación tiene como finalidad determinar la relación entre la facilitación del comercio y la gestión de riesgo aplicado por la Administración Aduanera en el despacho de importación para consumo, periodo 2018. Metodológicamente, se enmarcó en el tipo aplicado, nivel correlacional, con un diseño no experimental transversal. El método fue el hipotético – deductivo, porque se observó al problema, se formuló las hipótesis y se realizó la prueba oportuna. La población y muestra fue de 120 funcionarios que tengan relación con el despacho de importación para consumo. En relación a la instrumentalización, se han formulado dos instrumentos de recolección de datos y estos han pasado por los filtros correspondientes, cada uno de ellos con 24 y 26 ítems y con cinco alternativas de respuestas. En base a los resultados la investigación concluyó que existe relación favorable entre la facilitación del comercio y la gestión de riesgo aplicado por la Administración Aduanera en el despacho de importación para consumo, periodo 2018.Tesi

Estudio desde primeros principios de propiedades electrónicas y estructurales de sólidos

Los métodos de estudio teóricos de la materia denominados de primeros principios (o ab initio) se han desarrollado notablemente en las últimas décadas. Estos métodos permiten en la actualidad obtener información muy variada sobre sistemas muy complejos, empleando tan sólo principios y herramientas propias de la Mecánica Cuántica. Empleando estos métodos de primeros principios, en esta tesis se ha estudiado el efecto de la presión sobre dos tipos de sólidos cristalinos diferentes: el compuesto binario InAs, y los cinco materiales ternarios YLiF4, CaWO4, SrWO4, BaWO4 y PbWO4. En ambos casos se han estudiado principalmente las transiciones de fase estructurales bajo presión. En el estudio del compuesto InAs, los cálculos ab initio realizados reproducen correctamente el comportamiento observado experimentalmente a presiones moderadas, con transiciones desde la estructura zb de presión ambiente hacia la tipo NaCl, y de ésta hacia Cmcm. A presiones elevadas, se han examinado varias estructuras propuestas en InAs como fases estables a alta compresión, tales como la estructura tipo CsCl propuesta en el trabajo teórico de Mujica y Needs [Phys. Rev. B 55, 9659 (1997)]; las estructurtas tipo B10 y Pmma, estudiadas de forma teórica por Kim y colaboradores [Phys. Rev. B 60, R8449 (1999)]; y la estructura tipo Pmma desordenada, caracterizada experimentalmente por Pascarelli et al. [Europhys. Lett. 61 (4), 554 (2003)]. Se ha considerado también la estructura tipo Super-Cmcm, propuesta como estable en el compuesto InSb por Kelsey y Ackland [J. Phys.: Condens. Matter 12, 7161 (2002)]. Además, se ha analizado el efecto de la ordenación sobre la estabilidad de la red bcc (a la que pertenece la estructura tipo CsCl), lo que da lugar a estructuras casi-bcc tales como la tipo B11, que presentan la notable diferencia con respecto a la tipo CsCl de tener primeros vecinos del mismo tipo

Thirteenth Intercomparison Campaign of the Regional Brewer Calibration Center Europe: Lichtklimatisches Observatorium, Arosa, Switzerland: 30 July–10 August 2018

Editado por Alberto Redondas y Stoyka NetchevaThis thirteenth campaign was a joint exercise of the Regional Brewer Calibration Center for Europe (RBCC-E) and the Regional Dobson Calibration Center (RDCC-E) with the support of MeteoSwiss and of the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO). The following operations were performed by the RBCC-E during the intercomparison: Ozone calibration against the RBCC-E travelling reference (B#185) ; Compilation of the calibration histories of the instruments ; Evaluation of the Level 2 Eubrewnet ozone data for the period between intercomparisons

Negative pressures in CaWO4 nanocrystals

Tetragonal scheelite-type CaWO4 nanocrystals recently prepared by a hydrothermal method show an enhancement of its structural symmetry with the decrease in nanocrystal size. The analysis of the volume dependence of the structural parameters in CaWO4 nanocrystals with the help of ab initio total-energy calculations shows that the enhancement of the symmetry in the scheelite-type nanocrystals is a consequence of the negative pressure exerted on the nanocrystals; i.e., the nanocrystals are under tension. Besides, the behavior of the structural parameters in CaWO4 nanocrystals for sizes below 10 nm suggests an onset of a scheelite-to-zircon phase transformation in good agreement with the predictions from our ab initio calculations. CaWO4 nanocrystals exhibit a reconstructive-type mechanism for the scheelite-to-zircon phase transition that seems to follow the tetragonal path that links both structures. This result is in contrast with the mechanism recently proposed for this transition in bulk ZrSiO4 where the transition goes through an intermediate monoclinic [email protected]

Fourteenth Intercomparison Campaign of the Regional Brewer Calibration Centre Europe : El Arenosillo Atmospheric Sounding Station, Huelva, Spain, 17-28 June 2019

In this campaign, the Regional Brewer Calibration Center for Europe (RBCC-E) transferred its own absolute ozone calibration obtained from the Langley method at the Izaña Observatory to all other participating instruments. Such intercomparison campaigns, with a large number of participating instruments, provide an overview of the current state of ozone measurements being made by the European Brewer network. The instruments were compared with the RBCC-E standard Brewer#185 for ozone and with the European reference standard from the World Radiation Center (WRC) QASUME unit for UV

Soluble iron dust export in the high altitude Saharan Air Layer

Every summer huge amounts of desert dust particles are exported from the hyperarid subtropical Sahara to the North Atlantic the so-called Saharan Air Layer (SAL), a dry, warm and dust-laden corridor that expands from the North African coast (1-5 km.a.s.I.) to the Americas above the marine boundary layer. Because of the potential impact of the dust deposited on the ocean on marine biogeochemistry and climate, we studied the Fe solubility (in seawater) of atmospheric aerosols samples directly collected in the SAL off the North African coast, i.e, the fresh aerosols recently exported from the Sahara in the SAL. The aerosol sampling was performed at 2400 m.a.s.l. in Izana observatory in Tenerife island. In the total aerosols, we found low Fe concentrations and high fractional Fe solubility (FFS-2%) in the North Atlantic free troposphere airflows and high Fe concentrations and low FFS (-0.7%) within the SAL; the resulting FFS versus total dust (or total Fe) plot shows a hyperbolic trend attributed to the conservative mixing of 'fine combustion aerosols' and 'lithogenic mineral dust'. We then focused on the soluble Fe in the SAL Our results indicate that 70% of soluble Fe is associated with the dissolution of submicron dust particles, probably involving Fe-bearing clays. We found a FFS of submicron dust (-6%) higher than that typically observed in submicron particles of soil dust samples (<1%).This study is part of the project AEROATLAN e 2015-66229 -, funded by the Ministry of Economy and Competitiveness of Spain. M.I. García holds a research grant e TESIS20120054 e co-funded by the Canarian Agency for Research, Innovation and Information Society and the European Social Fund

Twelfth Intercomparison Campaign of the Regional Brewer Calibration Center Europe: El Arenosillo Atmospheric Sounding Station, Huelva, Spain, 29 May to 9 June 2017

Editado por Alberto Redondas y Stoyka NetchevaThe twelfth European Brewer Intercomparison Campaign was organized by the Regional Brewer Calibration Center for Europe (RBCC-E) in collaboration with the “Area of Instrumentation and Atmospheric Research Area” of Instituto Nacional de Tecnica Aeroespacial (INTA), with the support of the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) and the EUBREWNET ES1207 COST Action. Alongside the campaign, the ATMOZ (Traceability of Atmospheric Total Ozone) project workshop took place at the station. In addition, this event was also used as a demonstration exercise of the calibration methodologies and error assessment developed by the project (Gröbner et al., 2018)

Numerical modelling of pipelines with air pockets and air valves

[EN] This work considers the behaviour of air inside pipes when the air is expelled through air valves. Generally, the air shows isothermal behaviour. Nevertheless, when the transient is very fast, it shows adiabatic behaviour. In a real installation, an intermediate evolution between these two extreme conditions occurs. Thus, it is verified that the results vary significantly depending on the hypothesis adopted. To determine the pressure of the air pocket, the most unfavourable hypothesis (isothermal behaviour) is typically adopted. Nevertheless, from the perspective of the water hammer that takes place when the water column arrives at the air valve and abruptly closes, the most unfavourable hypothesis is the opposite (adiabatic behaviour). In this case, the residual velocity with which the water arrives at the air valve is higher, and, consequently, the water hammer generated is greater.Fuertes Miquel, VS.; López Jiménez, PA.; Martínez-Solano, FJ.; López-Patiño, G. (2016). Numerical modelling of pipelines with air pockets and air valves. Canadian Journal of Civil Engineering. 43(12):1052-1061. doi:10.1139/cjce-2016-0209S10521061431