Browsing by Issue Date, starting with "2015-03"
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- Assessment of groundwater contamination in an agricultural peri-urban area (NW Portugal): an integrated approachPublication . Barroso, M. Fátima; Ramalhosa, Maria João; Olhero, A.; Antão, M. C.; Pina, M. F.; Guimarães, L.; Teixeira, J.; Afonso, M. J.; Delerue-Matos, Cristina; Chaminé, Helder I.The excessive use of pesticides and fertilisers in agriculture has generated a decrease in groundwater and surface water quality in many regions of the EU, constituting a hazard for human health and the environment. Besides, on-site sewage disposal is an important source of groundwater contamination in urban and peri-urban areas. The assessment of groundwater vulnerability to contamination is an important tool to fulfil the demands of EU Directives. The purpose of this study is to assess the groundwater vulnerability to contamination related mainly to agricultural activities in a peri-urban area (Vila do Conde, NW Portugal). The hydrogeological framework is characterised mainly by fissured granitic basement and sedimentary cover. Water samples were collected and analysed for temperature, pH, electrical conductivity, chloride, phosphate, nitrate and nitrite. An evaluation of groundwater vulnerability to contamination was applied (GOD-S, Pesticide DRASTIC-Fm, SINTACS and SI) and the potential nitrate contamination risk was assessed, both on a hydrogeological GIS-based mapping. A principal component analysis was performed to characterised patterns of relationship among groundwater contamination, vulnerability, and the hydrogeological setting assessed. Levels of nitrate above legislation limits were detected in 75 % of the samples analysed. Alluvia units showed the highest nitrate concentrations and also the highest vulnerability and risk. Nitrate contamination is a serious problem affecting groundwater, particularly shallow aquifers, especially due to agriculture activities, livestock and cesspools. GIS-based cartography provided an accurate way to improve knowledge on water circulation models and global functioning of local aquifer systems. Finally, this study highlights the adequacy of an integrated approach, combining hydrogeochemical data, vulnerability assessments and multivariate analysis, to understand groundwater processes in peri-urban areas.
- Eruca sativa: Benefits as antioxidants source versus risks of already banned pesticidesPublication . Maia, M. Luz; Correia-Sá, Luísa; Coelho, Andreia; Barroso, M. Fátima; Domingues, Valentina F.; Delerue-Matos, CristinaEruca sativa (rocket salad) has been intensely consumed all over the world, insomuch as, this work was undertaken to evaluate the antioxidant status and the environmental contamination (positive and negative nutritional contribution) of leaves and stems from this vegetable. Antioxidant capacity of rocket salad was assessed by mean of optical methods, such as the total phenolic content (TPC), reducing power assay and DPPH radical scavenging activity. The extent of the environmental contamination was reached through the quantification of thirteen organochlorine pesticides (OCP) by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing gas chromatography tandem mass-spectrometry (GC-MS/MS). The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology.The extent of the environmental contamination was reached through the quantification of thirteen OCP by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing GC-MS/MS. The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology. This demonstrated that leaves presented more antioxidant activity than stems, emphasizing that leaves contained six times more polyphenolic compounds than stems. In what concerns the OCP occurrence, the average recoveries obtained at the three levels tested (40, 60 and 80 µg kg−1) ranged from 55% to 149% with a relative standard deviation of 11%, (except hexachrorobenzene). Three vegetables samples were collected from supermarkets and analysed following this study. According to data, only one sample achieved 16.21 of β-hexachlorocyclohexane, confirmed by GC-MS/MS. About OCP quantification, the data indicated that only one sample achieved 16.21 µg kg−1 of β-hexachlorocyclohexane, confirmed by GC-MS/MS, being the QuEChERS a good choice for the of OCPs extraction. Furthermore, the leaves consumption guaranty higher levels of antioxidants than stems.
- Predictivity Strength of the Spatial Variability of Phenanthrene Sorption Across Two Sandy Loam FieldsPublication . Soares, Antonio; Paradelo, Marcos; Moldrup, Per; Delerue-Matos, Cristina; Jonge, Lis W. deSorption is commonly agreed to be the major process underlying the transport and fate of polycyclic aromatic hydrocarbons (PAHs) in soils. However, there is still a scarcity of studies focusing on spatial variability at the field scale in particular. In order to investigate the variation in the field of phenanthrene sorption, bulk topsoil samples were taken in a 15 × 15-m grid from the plough layer in two sandy loam fields with different texture and organic carbon (OC) contents (140 samples in total). Batch experiments were performed using the adsorption method. Values for the partition coefficient K d (L kg−1) and the organic carbon partition coefficient K OC (L kg−1) agreed with the most frequently used models for PAH partitioning, as OC revealed a higher affinity for sorption. More complex models using different OC compartments, such as non-complexed organic carbon (NCOC) and complexed organic carbon (COC) separately, performed better than single K OC models, particularly for a subset including samples with Dexter n < 10 and OC <0.04 kg kg−1. The selected threshold revealed that K OC-based models proved to be applicable for more organic fields, while two-component models proved to be more accurate for the prediction of K d and retardation factor (R) for less organic soils. Moreover, OC did not fully reflect the changes in phenanthrene retardation in the field with lower OC content (Faardrup). Bulk density and available water content influenced the phenanthrene transport mechanism phenomenon.
- Constrained Consumption Shifting Management in the Distributed Energy Resources Scheduling Considering Demand ResponsePublication . Faria, Pedro; Vale, Zita; Batista, JoseDemand response concept has been gaining increasing importance while the success of several recent implementations makes this resource benefits unquestionable. This happens in a power systems operation environment that also considers an intensive use of distributed generation. However, more adequate approaches and models are needed in order to address the small size consumers and producers aggregation, while taking into account these resources goals. The present paper focuses on the demand response programs and distributed generation resources management by a Virtual Power Player that optimally aims to minimize its operation costs taking the consumption shifting constraints into account. The impact of the consumption shifting in the distributed generation resources schedule is also considered. The methodology is applied to three scenarios based on 218 consumers and 4 types of distributed generation, in a time frame of 96 periods.
- Contextual and Environmental Awareness Laboratory for Energy Consumption ManagementPublication . Gomes, Luis; Fernandes, Filipe; Faria, Pedro; Silva, Marco; Vale, Zita; Ramos, CarlosThe recent changes on power systems paradigm requires the active participation of small and medium players in energy management. With an electricity price fluctuation these players must manage the consumption. Lowering costs and ensuring adequate user comfort levels. Demand response can improve the power system management and bring benefits for the small and medium players. The work presented in this paper, which is developed aiming the smart grid context, can also be used in the current power system paradigm. The proposed system is the combination of several fields of research, namely multi-agent systems and artificial neural networks. This system is physically implemented in our laboratories and it is used daily by researchers. The physical implementation gives the system an improvement in the proof of concept, distancing itself from the conventional systems. This paper presents a case study illustrating the simulation of real-time pricing in a laboratory.
- Resource Scheduling in Residential Microgrids Considering Energy Selling to External PlayersPublication . Canizes, Bruno; Silva, Marco; Faria, Pedro; Ramos, Sérgio; Vale, ZitaThe operation of distribution networks has been facing changes with the implementation of smart grids and microgrids, and the increasing use of distributed generation. The specific case of distribution networks that accommodate residential buildings, small commerce, and distributed generation as the case of storage and PV generation lead to the concept of microgrids, in the cases that the network is able to operate in islanding mode. The microgrid operator in this context is able to manage the consumption and generation resources, also including demand response programs, obtaining profits from selling electricity to the main network. The present paper proposes a methodology for the energy resource scheduling considering power flow issues and the energy buying and selling from/to the main network in each bus of the microgrid. The case study uses a real distribution network with 25 bus, residential and commercial consumers, PV generation, and storage.
- 3D-nanostructured Au electrodes for the event-specific detection of MON810 transgenic maizePublication . Barroso, M. Fátima; Freitas, Maria; Oliveira, M. Beatriz P.P.; de-los-Santos-Álvarez, Noemí; Lobo-Castañón, María Jesús; Delerue-Matos, CristinaIn the present work, the development of a genosensor for the event-specific detection of MON810 transgenic maize is proposed. Taking advantage of nanostructuration, a cost-effective three dimensional electrode was fabricated and a ternary monolayer containing a dithiol, a monothiol and the thiolated capture probe was optimized to minimize the unspecific signals. A sandwich format assay was selected as a way of precluding inefficient hybridization associated with stable secondary target structures. A comparison between the analytical performance of the Au nanostructured electrodes and commercially available screen-printed electrodes highlighted the superior performance of the nanostructured ones. Finally, the genosensor was effectively applied to detect the transgenic sequence in real samples, showing its potential for future quantitative analysis.
- A Data-mining-based Methodology to support MV Electricity Customers' CharacterizationPublication . Ramos, Sérgio; Duarte, João; Duarte, F. Jorge; Vale, ZitaThis paper presents an electricity medium voltage (MV) customer characterization framework supportedby knowledge discovery in database (KDD). The main idea is to identify typical load profiles (TLP) of MVconsumers and to develop a rule set for the automatic classification of new consumers. To achieve ourgoal a methodology is proposed consisting of several steps: data pre-processing; application of severalclustering algorithms to segment the daily load profiles; selection of the best partition, corresponding tothe best consumers’ segmentation, based on the assessments of several clustering validity indices; andfinally, a classification model is built based on the resulting clusters. To validate the proposed framework,a case study which includes a real database of MV consumers is performed.
- Aplicação de ferramentas Kaizen na realização de auditorias internas e reporting do sistema de gestão integrado da AveladaPublication . Dias, Sara Alexandra dos Santos SoaresNa atual conjuntura económica, torna-‐se fundamental uma reflexão profunda das organizações sobre a forma como podem maximizar o seu retorno nos investimentos (ROI-‐Return On Investment), aumentar a sua competitividade nos diversos mercados, procurando atingir uma cultura de excelência operacional. A necessidade de uma maior eficiência na utilização dos seus recursos levou a Aveleda, líder de mercado do Vinho Verde, a desenvolver no final de 2011, um projeto de melhoria contínua com o Kaizen Institute, com o objetivo de melhoria da produtividade, eficiência interna, rentabilidade e redução do desperdício. A Aveleda, é uma empresa com um ,Sistema de Gestão Integrado (SGI) certificado de acordo com vários referenciais como a Qualidade, Segurança Alimentar, Ambiente e Energia. Este trabalho, apresenta a implementação de ferramentas Kaizen e a sua integração no processo de Auditorias Internas e reporting nos diferentes âmbitos do SGI. As ferramentas associadas ao desenvolvimento de Checklists, permitiram a criação de um sistema de monitorização e reporting do desempenho dos vários processos e atividades, com melhoria significativa na gestão dos desvios e eficácia nas ações tomadas contribuindo para um maior alinhamento e motivação das várias equipas na identificação de melhorias.
- The Alqueva hydro-meteorologic experimentPublication . Salgado, R.; Potes, M.; Albino, A.; Apolinário, J.; Barbosa, S.; Bárias, S.; Beliche, P.; Bortoli, D.; Canhoto, P.; Costa, M. J.; Fernandes, R.M.; Harrison, G. G.; Ilhéu, A.; Le Moigne, P.; Lima, Raúl; Lopes, F.; Lopes, T.; Marques, J.; Melgão, M.; Miranda, P. M.; Morais, M.; Murteira, M.; Nicoll, K.; Novais, M. H.; Nunes, S.; Parrondo, M. C.; Penha, A.; Pereira, S.; Policarpo, C.; Prior, V.; Rodrigues, C. M.; Rosado, J.; Sá, A.; Serafim, A.; Silva, H.; Soares, P. M. M.; Tlemçani, M.; Zavattieri, A.The ALqueva hydro-meteorological experiment, ALEX 2014 (http://www.alex2014.cge.uevora.pt) was an integrated field campaign with measurements of chemical, physical and biological parameters at different experimental sites in the Alqueva reservoir and in its surrounding region. With the main purpose of studing the lake-atmosphere interactions, the ALEX 2014 took place form June to September and comprised a three days Intensive Observation Period (IOP) from 22 to 24 July.
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