2,727 research outputs found

    Bottleneck prediction and data-driven discrete-event simulation for a balanced manufacturing line

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    Bottleneck identification is a relevant tool for continuous optimization of production lines. In this work, we implement a data-driven discrete-event simulator (DDS) based on experimental distributions, obtained from real historical data. The DDS allows to analyse the behavior of a balanced manufacturing line at Bosch Thermotechnology, under different hypotheses. It shows that some scenarios perceived as likely to increase output may actually decrease production metrics, reveals the importance of line injection rates, and leads to the need for adequate real time bottleneck forecasting tools, which allow shift managers intervention in a useful time frame. Eleven prediction models are tested, where a random forest and a multi-layer perceptron attain the best performances (above 95% in all metrics). This data flow is operationalized through a micro-services pipeline which is briefly discussed.publishe

    The use of simulation in self-perception of learning in occupational therapy students

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    This study aimed to assess the self-perception of students’ learning in Occupational Therapy undergraduate students of School of Health of the Polytechnic of Porto after exposure to a simulated situation of an information collection interview for an occupational profile.info:eu-repo/semantics/publishedVersio

    Application of lean approaches and techniques in an automotive company

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    In this paper are applied lean approaches and techniques in an industrial environment at Preh Portugal, Lda., a Company involved in the automotive sector located in Trofa, Portugal. This work makes use of the action-research methodology, aiming to diagnose the production system and to implement lean production procedures in order to optimize the Mizusumashi that supplies several production sections, about plastic Injection, cutting and painting. The results obtained enabled to obtain significant improvements on this Company at several factory management and operational levels.This work was supported by FCT “Fundação para a Ciência e a Tecnologia” under the program: PEst20152020.info:eu-repo/semantics/publishedVersio

    Assessment of the geological heritage of Cape Mondego Natural Monument (Central Portugal)

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    In the western coast of Portugal, Cape Mondego is a well-known set of outcrops due to its international stratigraphic relevance given by the establishment of two stratotypes: the Global Boundary Stratotype Section and Point (GSSP) for the base of the Bajocian Stage and the Auxiliary Stratotype Section and Point (ASSP) for the base of the Bathonian Stage. The remarkable geodiversity of these Jurassic outcrops justifies the implementation of strategies in order to conserve and promote the geosites, which include a rich palaeontological record of macrofossils, microfossils and dinosaur footprints. Based on the exceptional quality of the geological record, on its international importance and on its high scientific and educational values, this area was classified in 2007 as Natural Monument. However, no geosite systematic inventory was ever done. In this work, a systematic identification, characterization and assessment of geosites was done in the Natural Monument. Based on fieldwork and published data, a first set of 32 potential geosites was identified taking into account their scientific, educational and touristic values. After the application of three criteria (representativeness, singularity and proximity) this group of 32 potential geosites was reduced to 12. These 12 geosites were assessed resulting on the establishment of a medium to high ranks for both educational and geotouristic potential uses. Based on this assessment, some valuing strategies were proposed, aiming at the sustainable use and the promotion of the Natural Monument geosites, within the scope of both educational and geotouristic activities addressed to secondary school students and the general public

    Dyeing of PA6.6 fibers - Effect of solvent and temperature on thermal properties

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    Dyeing fibers at low temperatures has many advantages such as savings in energy and avoiding alterations to the physical properties of the fibers being dyed or other fibers also present in blends, The problem of low temperature dyeing in synthetic fibers is that it difficults the dye diffusion into the fiber. In the case of polyamide 6.6 microfibers, by using benzyl alcohol as an auxiliary dyeing, it was shown that good diffusion was obtained for the dye exhaustion with metal complex dyes at temperatures more than 30°C below the normal dyeing temperature for the dye exhaustion with metal complex dyes. Using thermal analysis methods these results were shown to be caused by the lowering of the T g of the fiber when in the presence of benzyl alcohol.Fundação para a Ciência e a Tecnologia (FCT

    Frequency of micronuclei and of other nuclear abnormalities in erythrocytes of the grey mullet from the Mondego, Douro and Ave estuaries—Portugal

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    Fish are bioindicators of water pollution, and an increased rate of their erythrocyte nuclear morphological abnormalities (ENMAs)—and particularly of erythrocyte micronuclei (EMN)—is used as a genotoxicity biomarker. Despite the potential value of ENMAs andMN, there is scarce information about fish captured in Iberian estuaries. This is the case of the Portuguese estuaries of the Mondego, Douro and Ave, suffering from different levels of environmental stress and where chemical surveys have been disclosing significant amounts of certain pollutants. So, the aim of this study was to evaluate genotoxicants impacts and infer about the exposure at those ecosystems, using the greymullet (Mugil cephalus) as bioindicator and considering the type and frequency of nuclear abnormalities of erythrocytes as proxies of genotoxicity. Sampling of mullets was done throughout the year in the important Mondego, Douro and Ave River estuaries (centre and north-western Portugal). The fish (total n=242) were caught in campaigns made in spring–summer and autumn– winter, using nets or fishing rods. The sampled mullets were comparable between locations in terms of the basic biometric parameters. Blood smears were stained with Diff-Quik to assess the frequencies of six types of ENMAs and MN (given per 1,000 erythrocytes). Some basic water physicochemical parameters were recorded to search for fluctuations matching the ENMAs. Overall, the most frequent nucleus abnormality was the polymorphic type, sequentially followed by the blebbed/ lobed/notched, segmented, kidney shaped, vacuolated,MNand binucleated. The total average frequency of the ENMAs ranged from 73‰in the Mondego to 108‰in the Ave. The polymorphic type was typically ≥50 % of the total ENMAs, averaging about 51‰, when considering all three estuaries. The most serious lesion—the MN—in fish from Mondego and Douro had a similar frequency (≈0.38‰), which was significantly lower than that in the Ave (0.75‰). No significant seasonal differences existed as to the MN rates and seasonal differences existed almost only in the Douro, with the higher values in AW. In general, the pattern of ENMAs frequencies was unrelated with the water physicochemical parameters. Considering the data for both the total ENMAs and for each specific abnormality, and bearing in mind that values of MN in fish erythrocytes >0.3‰ usually reflect pollution by genotoxicants, it is suggested that mullets were likely being chronically exposed to such compounds, even in the allegedly less polluted ecosystem (Mondego). Moreover, data supported the following pollution exposure gradient: Mondego<Douro<Ave. The scenario and inferences nicely agree with the published data from chemical monitoring.This work was partially supported by the European Regional Development Fund (ERDF) funds through the Competitiveness and Trade Expansion Program (COMPETE), and by National Funds provided by Fundação para a Ciência e a Tecnologia (FCT), via the research projects PTDC/MAR/70436/2006, PEst-C/MAR/LA0015/ 2011, PEst-C/MAR/LA0015/2013, and also by the PhD grant SFRH/BD/25746/2005

    Desenvolvimento de uma solução de processamento de imagem em ambiente industrial

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