Solar Irradiance (Global, Direct and Diffuse) Quality Control Methodologies. Review: Application to Time Series Measured At LES/LNEG, Lisboa, Portugal

ABSTRACT: Solar irradiance spatial and temporal quantification is essential to the development, implementation, and operation of solar systems, being used throughout a solar project lifecycle. It is crucial to have good quality data measured in meteorological and radiometric ground stations in order to enable the calibration and validation of irradiance models and data series. The Solar Energy laboratory at LNEG operates a meteorological station gathering relevant parameters to characterize the solar irradiation profile for the city of Lisbon in Portugal. This work presents and compares the application of different methodologies used for quality control of solar irradiance measurements. Three methods - the CIE (1994) / Muneer and Fairooz (2002), the QCRad and the IEC - were tested against two synthetic data sets: a clear-sky year and a typical meteorological year randomly and uniformly infused with errors. IEC showed to have limitation regarding the extreme value criteria for beam normal irradiance and CIE for the diffuse horizontal irradiance. The QCRad presented the best performance, with total sensitivity above 80% and maximum specificity. This method was applied to the measured data of LES-LNEG between 2014 and 2018. Most of the detected errors were detected during the coherence test stage, having a higher prevalence between 2015 and mid-2016, highlighting the need to modify the diffuse horizontal irradiance measuring system.info:eu-repo/semantics/publishedVersio

SILVAQUA PROJECT. Avaliação dos impactes das alterações climáticas sobre os recursos hídricos e a fixação de CO2 por povoamentos florestais de crescimento rápido em Portugal. Primeiros resultados

Congresso Florestal Nacional: A floresta e as gentes - Actas das ComunicaçõesEstudos recentes referem o impacte das alterações climáticas na evapotranspiração e recursos hídricos, em áreas florestais povoadas com espécies de crescimento rápido, em Portugal (Coelho et al., 2000). Na eventualidade de se verificarem os cenários de diminuição da quantidade de precipitação previstos para o sul da Europa (Parry, 2000), torna-se previsível que várias espécies entrem em stress hídrico tal como Eucalyptus globulus (Coelho et al, 2001), provocando alterações no crescimento dos povoamentos, na decomposição da manta morta e no consumo de água. Espera-se ainda um forte impacte na fixação do CO2 atmosférico. O impacte destas alterações nos processos hidrológicos em solos e vertentes, sob povoamentos de crescimento rápido, é ainda pouco conhecido, sendo o seu conhecimento fundamental para a compreensão dos fenómenos hidrológicos e, essencial no planeamento e gestão eficiente destes recursos. O projecto Silvaqua (POCTI/MGS/49210/2002) foi elaborado no âmbito desta temática, e consiste numa abordagem a várias escalas. (i) estudo dos padrões de variação da humidade do solo para uma série de parcelas onde a humidade do solo é registada segundo diversas redes de sondas de TDR; (ii) monitorização intensiva do crescimento das árvores e arbustos, da queda de folhada e da decomposição da manta morta; (iii) estudo dos processos hidrológicos nas vertentes (nomeadamente caracterização do escoamento e da evapotranspiração) com a delimitação de várias parcelas fechadas e a instrumentação de pequenas bacias hidrográficas; A análise dos resultados permitirá estabelecer os mecanismos de interacção entre as alterações climáticas, o crescimento da vegetação, os processos hidrológicos e os recursos hídricos. O impacte ambiental dos cenários climáticos previstos (Parry, 2000) sobre os recursos hídricos, em termos de alterações de intercepção, de padrões de humidade do solo, de hidrologia das vertentes e das bacias e, sobre a fixação do CO2, em termos de crescimento da vegetação e da dinâmica da camada de manta morta, será estabelecido para vários tipos de povoamentos de eucalipto. A área de estudo localiza-se a 15 km-Este de Águeda e insere-se na bacia hidrográfica do Rio Águeda, na Serra do Caramulo. É efectuado anualmente um inventário florestal das duas micro-bacias em estudo. Os dados obtidos no âmbito do projecto serão usados no modelo GLOB-3PG, de maneira a estimar a produtividade dos povoamentos e a resposta em termos hidrológicos, para diversos cenários climáticos alternativos

Measuring Adherence to Inhaled Control Medication in Patients with Asthma: Comparison Among an Asthma App, Patient Self‐Report and Physician Assessment

Background: Previous studies have demonstrated the feasibility of using an asthma app to support medication management and adherence but failed to compare with other measures currently used in clinical practice. However, in a clinical setting, any additional adherence measurement must be evaluated in the context of both the patient and physician perspectives so that it can also help improve the process of shared decision making. Thus, we aimed to compare different measures of adherence to asthma control inhalers in clinical practice, namely through an app, patient self-report and physician assessment. Methods: This study is a secondary analysis of three prospective multicentre observational studies with patients (≥13 years old) with persistent asthma recruited from 61 primary and secondary care centres in Portugal. Patients were invited to use the InspirerMundi app and register their inhaled medication. Adherence was measured by the app as the number of doses taken divided by the number of doses scheduled each day and two time points were considered for analysis: 1-week and 1-month. At baseline, patients and physicians independently assessed adherence to asthma control inhalers during the previous week using a Visual Analogue Scale (VAS 0-100). Results: A total of 193 patients (72% female; median [P25-P75] age 28 [19-41] years old) were included in the analysis. Adherence measured by the app was lower (1 week: 31 [0-71]%; 1 month: 18 [0-48]%) than patient self-report (80 [60-95]) and physician assessment (82 [51-94]) (p 0.05). There was a moderate correlation between patient self-report and physician assessment (ρ = 0.596, p < 0.001). Conclusions: Adherence measured by the app was lower than that reported by the patient or the physician. This was expected as objective measurements are commonly lower than subjective evaluations, which tend to overestimate adherence. Nevertheless, the low adherence measured by the app may also be influenced by the use of the app itself and this needs to be considered in future studies.info:eu-repo/semantics/publishedVersio

Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods

With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass—carbohydrates, lipids, and proteins—there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage

Bancruptcy in a model of unsecured claims

We study a two periods model of incomplete markets with nominal assets unsecured by collateral, where agents can go bankrupt but there are no bankruptcy penalties entering directly in the utility function. We address two cases: first, a proportional reimbursement rule under bounded short sales and limited liability and, secondly, a nonproportional reimbursement rule, favoring smaller claims, without bounds on short-sales, but assuming that liability approaches total garnishment as debt goes to infinity.Bankruptcy, Incomplete markets, Limited liability, Spread.

Drought Trends in the Iberian Peninsula over the Last 112 Years

The Iberian Peninsula (IP) is a drought-prone area located in the Mediterranean which presents a significant tendency towards dryness during the last decades, reinforcing the need for a continuous monitoring of drought. The long-term evolution of drought in the IP is analyzed, using the Standardized Precipitation Evaporation Index (SPEI) and the Standardized Precipitation Index (SPI), for the period of 1901–2012 and for three subperiods: 1901–1937, 1938–1974, and 1975–2012. SPI and SPEI were calculated with a 12-month time scale, using data from the Climatic Research Unit (CRU) database. Trends in the drought indices, precipitation, and reference evapotranspiration (ET0) were analysed and series of drought duration, drought magnitude, time between drought events, and mean intensity of the events were computed. SPI and SPEI significant trends show areas with opposite signals in the period 1901–2012, mainly associated with precipitation trends, which are significant and positive in the northwestern region and significant and negative in the southern areas. Additionally, SPEI identified dryer conditions and an increase in the area affected by droughts, which agrees with the increase in ET0. The same spatial differences were identified in the drought duration, magnitude, mean intensity, and time between drought events