Modelação matemática da camada de plasma em microcanais

Neste estudo apresenta-se uma proposta de modelação matemática da camada de plasma observada em escoamentos sanguíneos. Numa fase inicial, a resolução do problema fez uso da otimização não linear para encontrar o modelo matemático que minimiza o erro quadrático não linear entre o modelo e os dados numéricos que caracterizam a camada de plasma. Para tal, foram testados os algoritmos Simulated Annealing, Pattern Search, Algoritmo Genético e Quasi-Newton. Neste estudo conclui-se que o método de otimização que obteve melhores resultados foi o Algoritmo Genético. Também foi possível concluir que o melhor modelo para aproximar os dados numéricos que caracterizam a camada de plasma presente em escoamentos sanguíneos é baseado na soma de funções trigonométricas.Os autores agradecem à FCT, COMPETE, QREN e União Europeia (FEDER) no âmbito dos projetos PTDC/SAU-ENB/116929/2010 e EXPL/EMS-SIS/2215/2013.info:eu-repo/semantics/publishedVersio

Petri nets approach for designing the migration process towards industrial cyber-physical production systems

Presently, many industries are facing strong challenges related to the demand of customized and high-quality products. These pressures lead to internal company's conflicts where current production systems have a rigid structure, forcing the company into a organization stall when a fast product change is required. Therefore, the need to smoothly migrate traditional systems into more feature-rich and cost-effective systems, namely Cyber-Physical Production Systems (CPPS), became a highly discussed topic. PERFoRM project focuses the conceptual transformation of existing production systems towards plug\&produce ones to achieve flexible and reconfigurable manufacturing environments. In particular, the smooth migration process is considered crucial to effectively transpose existing production systems into truly CPPS. This paper describes the use of Petri nets to design the migration process under the PERFoRM perspective, taking advantage of its inherent capabilities to design, analyze, simulate and validate such complex processes.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 680435.info:eu-repo/semantics/publishedVersio

Antifungal susceptibility of Candida albicans and Candida dubliniensis biofilms vs planktonic cells

Candida albicans is the major etiological agent of oral infections. Recently a new species closely related to Candida albicans, Candida dubliniensis, was isolated from the mouth of HIV patients. Due to their similar surface properties, both species have equal abilities to colonise the oral cavity and to form biofilms. Candidal infections are often difficult to eradicate due to the resistance of biofilms to antifungal agents. In this work the susceptibility of two strains of Candida albicans and of two strains of Candida dubliniensis biofilms to flucanazole and amphotericin B was evaluated and compared to that of planktonic cells. Antifungal testing to determine the MICs of planktonic cells were performed according to the NCCLS M27 A broth micro dilution method. The same methodology was adapted for biofilm susceptibilities. Additionally the effect of the presence of artificial saliva on antifungal susceptibilities was evaluated. All Candidal strains grown in planktonic forms were susceptible to both antifungal agents (MIC80<8ìg/ml), according to the NCCLS guidelines. As expected a great decrease in antifungal susceptibility was detected in all Candidal biofilms for both antifungal agents, with special relevance for flucanazole, in which MIC50>12 ìg/ml. Antifungal susceptibility was affected by artificial saliva, in this medium candidal cells exhibited a smaller susceptibility than in RPMI medium probably due to their lower metabolic activity

PERFoRM migration strategy towards cyber-physical systems

In the last years, many organizations intend to convert their existing production systems towards ones that are characterized by adaptability, openness, flexibility and modularity. This requires a redesign of existing information processing systems especially related to control, leading possibly to the implementation of Cyber-Physical Production Systems (CPPS). However, the implementation of new control technologies will have a direct impact on the normal operational status of production while engineers will also face several challenges and obstacles in adopting intelligent automation systems. New step-wise migration strategies are required to holistically support industries in their journey towards CPPS taking into account technical, economic and social aspects. This work describes the definition of a migration approach for innovative production systems, particularly those CPPS that are developed under the PERFoRM ecosystem, establishing guidelines for a smooth migration from a traditional system to agile plug-and-produce systems in a secure and efficient way. The designed migration approach comprises five phases, namely Preparation, Options Investigation, Design, Implementation and Deployment, sustained by three different migration strategies, namely One-Shot, Parallel and Phased. The modelling of the migration process uses the Petri nets formalism taking advantage of its inherent capabilities to synthesize the process specifications but also to verify, simulate and validate the correctness of the system specifications during the design phase.info:eu-repo/semantics/publishedVersio

Intelligent and predictive maintenance in manufacturing systems

In recent years manufacturing companies have been facing a major shift in the manufacturing requirements, for example the shift in demand for highly customized products resulting in a shorter product life cycle, rather than the traditional mass production of standardized products. As a consequence of the change, the enterprises are facing the need to adapt, forcing all sectors of the manufacturing activity to move accordingly. Maintenance is one of the major activities in manufacturing as it highly influences production productivity and quality, and has a direct impact on production cost and customer satisfaction. Nowadays, corrective and scheduled maintenance are widely implemented. However, the manufacturing world need to adapt to this new reality by implementing new, intelligent and innovative maintenance systems capable of predicting in advance possible failures. Lately, predictive maintenance systems and tools have been developed and continue to be studied and improved. However, companies do not have enough trust on these systems to fully rely on them. Considering all these aspects, the work developed on this thesis introduces a system architecture for an intelligent predictive maintenance system based on the Condition-Based Maintenance (CBM) to be used in the Catraport case study, focusing particularly on the development of the monitoring module of the system architecture. This module comprises a tool developed by using Node-RED that displays the collected data alongside with the warnings triggered by cross-checking the incoming data with implemented decision rules, through the use of graphics and text. Additionally, an Android mobile application was also developed to allow consulting remotely the operating state of the assets.Nos últimos anos, as empresas de manufatura têm enfrentado uma grande mudança nos requisitos de fabrico, nomeadamente, na procura por produtos altamente personalizados, resultando num ciclo de vida do produto mais curto, contrariamente à tradicional produção em massa de produtos padronizados. Como consequência desta mudança, as empresas, bem como todos os setores da atividade de manufatura, enfrentam a necessidade de se adaptar. A manutenção é uma das principais atividades de fabrico, visto que influência fortemente a produtividade e a qualidade da produção, e tem um impacto direto no custo do produto e na satisfação do cliente. Atualmente, as estratégias de manutenção corretiva e programada são amplamente implementadas. No entanto, o mundo da manufatura precisa de se adaptar à nova realidade, implementando sistemas de manutenção novos, inteligentes e inovadores, capazes de prever possíveis falhas. Ultimamente, os sistemas e ferramentas de manutenção preditiva têm sido desenvolvidos e continuam a ser estudados e melhorados. No entanto, as empresas não possuem confiança suficiente nesses sistemas para os implementar nas suas instalações. Considerando todos esses aspetos, o trabalho desenvolvido nesta dissertação introduz uma arquitetura para um sistema inteligente de manutenção preditiva baseado na técnica Condition- Based Maintenance (CBM) a ser usado no estudo de caso da Catraport, focando-se particularmente no desenvolvimento do módulo de monitorização da arquitetura. Este módulo compreende uma ferramenta desenvolvida com recurso ao Node-RED que exibe os dados colecionados. Adicionalmente são apresentados avisos originados pelo cruzamento dos dados recebidos com as regras de decisão implementadas. Além disso, uma aplicação móvel Android também foi desenvolvida para permitir a consulta remota o estado operacional dos equipamentos

THE ENVIRONMENTAL IMPACT OF USING COPPER SULPHATE TO AVOID GRAPEVINE POWDERY MILDEW IN THREE VINEYARDS OF THE DOURO REGION, PORTUGAL

Copper-based fungicides have been used in vineyards throughout the world, for many decades to protect against downy mildew. However, their use results in an accumulation of Cu in surface soils which can potentially impact on the biological health of the soil and could be transported and stored in the sediments deposited close to valley bottoms. In Douro region, northern of Portugal, vineyards are located on steep slopes and are susceptible to accelerated soil erosion. In this study, 50 soils samples were collected in 3 vineyards of different ages, one with more of 50 years, other with more 15 years and one recently planted. Two rivers converge into a water reservoir located close to vineyards. Five samples of stream sediment, pore water and superficial water were collected in the rivers and reservoir. The total Cu (CuT) content in the soils varies between 17.8 and 211 mg/Kg (mean = 79.4 mg/Kg). However in the old vineyard the Cu concentration is higher than in the others (mean value of 144.8 mg/kg). The total Cu content in stream sediments ranges from 19.4 to 35 mg/Kg (mean = 26.1). The average Cu concentration in soils is 3 times higher than in sediments. The solid phase distribution of copper in stream sediments shows that the metal is associated with Fe-Oxyhydroxides and silicates, indicating that most Cu in the sediment has a geogenic source. In sediment pore water the Cu content is always below 2µg/L, with the exception of the sample collected in the reservoir. For superficial waters no Cu was detected. These results suggest that the rate of erosion is low and the contribution of soils Cu in stream sediments is irrelevant. The sediment core was divided in 31 sub-samples and a pore-water sample was extracted when possible. The distribution of CuTalong the profile seems shows a slight increase with depth, with values ranging from 55.3 (surface) to 73.8 mg/Kg. In the pore water, Cu distribution shows an antipathetic patter

Air Influence on the Temperature inside a Concrete Bridge Box Section

The temperature on a bridge is a complex phenomena caused by several sources and it is quite difficult to forecast. Its effects cannot be ignored and during the last decades various studies have been made in this field. In order to reduce the complexity of these investigations, some simplifications, which do not entail large risks, are admitted making the problem easier to analyse. The main objective of this thesis is to analyse the thermal influence of the air temperature inside a concrete bridge box cross-section. Usually this ‘detail’ is ignored or simplified by the investigators. With the work developed and presented in this thesis it is possible to understand the dimension of the error introduced in the studies every time this simplification is introduced. To fulfil this purpose, two finite element models were developed in order to compare with experimental values. The experimental values were collected using the instrumentation installed on the new Svinesund Bridge in Sweden. In both the models (A and B) several thermal sources were introduced affecting the cross section from the outside such as air temperature, solar radiation and the night radiance. The difference between the two models is that in the first model (A) the air inside the box cross-section is taken into account and in the second model (B) that air is ignored. The quality of the fit of the values obtained using the models A and B with the experimental values from Svinesund allow to take the conclusions of this work. The difference between the models does not indicate that changes in this detail must be included in the future thermal studies

Geochemistry, mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon

An urban survey of Lisbon, the largest city in Portugal, was carried out to investigate its environmental burden, emphasizing metallic elements and their public health impacts. This paper examines the geochemistry of lead (Pb) and its influence on human health data. A total of 51 soil samples were collected from urban recreational areas used by children to play outdoors. The semi-quantitative analysis of Pb was carried out by inductively coupled plasma mass spectrometry after an acid digestion. X-ray diffraction was used to characterize the soil mineralogy. The solid-phase distribution of Pb in the urban soils was investigated on a subset of 7 soils, out of a total of 51 samples, using a non-specific sequential extraction method coupled with chemometric analysis. Oral bioaccessibility measurements were obtained using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives of the study are as follows: (1) investigation of Pb solid-phase distribution; (2) interpretation of Pb oral bioaccessibility measurements; (3) integration of metal geochemistry with human health data; and (4) understanding the influence of geochemistry and mineralogy on oral bioaccessibility. The results show that the bioaccessible fraction of Pb is lower when major metal fractions are associated with less soluble soil phases such as Fe oxyhydroxides, and more increased when the metal is in the highly soluble carbonate phase. However, there is some evidence that the proportion of carbonates in the soil environment is also a key control over the oral bioaccessibility of Pb, irrespective of its solid-phase fractionation

Long-term application of the organic and inorganic pesticides in vineyards: Environmental record of past use

Areas such as Douro Demarcated Region (Portugal), where vineyards are frequently located on steep slopes of narrow valleys, can be particularly sensitive to runoff and erosion processes. These particular conditions are expected to enhance the transport of pollutants, acting as a potential source of contamination to freshwater systems. The intense vine cultivation in this region includes decades of pesticides application, that have resulted in the accumulation of these chemicals and its degradation products in the vineyards soils and sediments. Residues of several pesticides related to agricultural activities were found in soils, with older vineyards showing higher levels of Cu and banned insecticides (such as DDT). The metabolite 4,4-DDE was the compound found at higher levels in soils and in sediments. The relatively high levels in more recent sediments suggest that soils are still a source of contamination. Levels of currently used pesticides were low, which is related with their physicochemical properties, the application period, and climacteric conditions