216 research outputs found

    Comparisons between synchronizing circuits to control algorithms for single-phase active converters

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    This paper presents a comparative analysis between synchronizing circuits applied to control algorithms for single-phase active converters. One of these synchronizing circuits corresponds to the single-phase PLL (Phase Locked Loop), implemented in α-β coordinates, whereas the other one corresponds to the E-PLL (Enhanced PLL). These synchronizing circuits are compared in several aspects as processing and settling time and memory space requirements. Moreover, the performance of a single-phase back-to-back converter is also presented, with its control algorithm based on these Synchronizing Circuits. Each one of the control algorithms were implemented in a DSP microprocessor TMS320F2812F from Texas Instruments. Simulation and experimental results, through a back-to-back converter prototype, are presented.Fundação para a Ciência e a Tecnologia (FCT

    Species richness and biomass of understory vegetation in a Eucalyptus globulus Labill. coppice as affected by slash management

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    The aim of this study was to assess the effect of different slash management practices on understory biodiversity and biomass in Eucalyptus globulus coppices in Central Portugal. The experiment consisted of four treatments: (a) removal of slash (R), (b) broadcast over the soil (S), (c) as in S but concentrating woody residues between tree rows (W) and (d) incorporation of slash into soil by harrowing (I). Understory vegetation was surveyed during 1–6, 9, and 10 years, the proportion of soil cover by plant species estimated, and diversity and equitability indexes determined. Above ground understory biomass was sampled in years 2–6, 9, and 10. The highest number of species in most years occurred in plots where slash was removed. Differences between treatments in the proportion of plant soil cover were never significant, whereas differences in diversity index were only occasionally significant and apparently related to the number of species. Thus, differences in the equitability index were not significant. Understory biomass did not decrease during the rotation period, and was usually highest in R and I, and lowest in S, but not significantly different. At the end of the rotation period, understory biodiversity indices and biomass were apparently independent of slash treatment

    Development and experimental assessment of a numerical modelling code to aid the design of profile extrusion cooling tools

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    On the extrusion of thermoplastic profiles, upon the forming stage that takes place in the extrusion die, the profile must be cooled in a metallic calibrator. This stage must be done at a high rate, to assure increased productivity, but avoiding the development of high temperature gradients, in order to minimize the level of induced thermal residual stresses. In this work, we present a new coupled numerical solver, developed in the framework of the OpenFOAM® computational library, that computes the temperature distribution in both domains simultaneously (metallic calibrator and plastic profile), whose implementation aimed the minimization of the computational time. The new solver was experimentally assessed with an industrial case study.SFRH/BPD/100353/2014info:eu-repo/semantics/publishedVersio

    Genomic analysis of four strains of Corynebacterium pseudotuberculosis bv. Equi isolated from horses showing distinct signs of infection.

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    The genomes of four strains (MB11, MB14, MB30, and MB66) of the species Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, completely assembled, and their gene content and structure were analyzed. The strains were isolated from horses with distinct signs of infection, including ulcerative lymphangitis, external abscesses on the chest, or internal abscesses on the liver, kidneys, and lungs. The average size of the genomes was 2.3 Mbp, with 2169 (Strain MB11) to 2235 (Strain MB14) predicted coding sequences (CDSs). An optical map of the MB11 strain generated using the KpnI restriction enzyme showed that the approach used to assemble the genome was satisfactory, producing good alignment between the sequence observed in vitro and that obtained in silico. In the resulting Neighbor-Joining dendrogram, the C. pseudotuberculosis strains sequenced in this study were clustered into a single clade supported by a high bootstrap value. The structural analysis showed that the genomes of the MB11 and MB14 strains were very similar, while the MB30 and MB66 strains had several inverted regions. The observed genomic characteristics were similar to those described for other strains of the same species, despite the number of inversions found. These genomes will serve as a basis for determining the relationship between the genotype of the pathogen and the type of infection that it causes

    Towards an ergonomic assessment framework for industrial assembly workstations - a case study

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    Work-related musculoskeletal disorders (WMSD) are one of the main occupational health problems. The best strategy to prevent them lies on ergonomic interventions. The variety of industrial processes and environments, however, makes it difficult to define an all-purpose framework to guide these ergonomic interventions. This undefinition is exacerbated by recurrent introduction of new technologies, e.g., collaborative robots. In this paper, we propose a framework to guide ergonomics and human factors practitioners through all stages of assessment and redesign of workstations. This framework was applied in a case study at an assembly workstation of a large furniture enterprise. Direct observation of work activity and questionnaires were applied to characterize the workstations, the process, and the workers’ profiles and perceptions. An ergonomic multi-method approach, based on well-known and validated methods (such as the Finnish Institute of Occupational Health and Rapid Upper Limb Assessment), was applied to identify the most critical risk factors. We concluded that this approach supports the process redesign and tasks’ allocation of the future workstation. From these conclusions, we distill a list of requirements for the creation of a collaborative robot cell, specifying which tasks are performed by whom, as well as the scheduling of the human-robot collaboration (HRC).This work has been supported by NORTE-06-3559-FSE-000018, integrated in the invitation NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF). This work has been also supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

    Olive tree (Olea europaea L.) diversity in traditional small farms of Ficalho, Portugal

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    The genetic diversity of “Gama” and “Bico de Corvo”, local cultivars of olive tree (Olea europaea) from seven traditional orchards of Ficalho (Alentejo region, Portugal), was studied to characterize the local diversity and assess the level of on farm diversity. Two different analytical systems were used: endocarp morphological characteristics and genetic analysis by microsatellite markers (Simple Sequence Repeats or SSR). The seven screened loci were polymorphic and allowed the identification of 23 distinct SSR profiles within the 27 trees analyzed. A total of 52 different alleles were scored, with an average of 7.43 alleles/SSR locus, and considerable genetic diversity was found. Neighbor-Joining algorithm cluster analysis and principal co-ordinate analysis (PCoA) allowed for the identification of the genetic relationships between several accessions. The 27 Olea accessions were clearly separated into three different groups. SSR analysis was more precise than endocarp characterization in the classification of genetic diversity among the olive tree cultivars. The study shows reasonable olive tree diversity in Ficalho, indicating that these traditional orchards are important reservoirs of old minor cultivars and incubators of new genotypesinfo:eu-repo/semantics/publishedVersio

    IL-2, IL-5, TNF-α and IFN-γ mRNA expression in epidermal keratinocytes of systemic lupus erythematosus skin lesions

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    OBJECTIVE: To analyze cytokine gene expression in keratinocytes from patients with systemic lupus erythematosus (SLE). INTRODUCTION: Keratinocytes represent 95% of epidermal cells and can secrete several cytokines. METHODS: Keratinocytes were obtained by laser microdissection from 21 patients with SLE (10 discoid and 11 acute lesions) at involved and uninvolved sites. All patients were receiving a low/moderate prednisone dose and 18 were receiving chloroquine diphosphate. IL-2, IL-5, TNF-α and IFN-γ gene expression was evaluated by real-time PCR and expressed as the ratio (R) to a pool of skin samples from 12 healthy volunteers. RESULTS: Heterogeneity in cytokine gene expression was found among patients with SLE. Eighteen of 38 valid SLE samples (47%) presented overexpression (R>1) of at least one cytokine. Lesional skin samples tended to show higher cytokine expression than samples from uninvolved skin (p = 0.06). IL-5 and IFN-γ were the most commonly overexpressed cytokines. Samples with cytokine overexpression corresponded to more extensive and severe lesions. Prednisone dose did not differ between samples without cytokine overexpression (15.71±3.45 mg/day) and those with overexpressed cytokines (12.68±5.41 mg/day) (p = 0.216). Samples from all patients not receiving diphosphate chloroquine had at least one overexpressed cytokine. CONCLUSIONS: The heterogeneous keratinocyte cytokine gene expression reflects the complex immunological and inflammatory background in SLE. Patients with severe/extensive skin lesions showed a higher frequency of cytokine gene overexpression. Increased IFN-γ and IL-5 expression suggests that Th1 and Th2 cells are involved in SLE skin inflammation. The possibility that prednisone and antimalarial drugs may have contributed to low cytokine gene expression in some samples cannot be ruled out.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Brazilian Society of RheumatologyUniversidade Federal do ParáUniversidade Federal de São Paulo (UNIFESP) Rheumatology DivisionFleury Medicine and Health Research and Development InstituteCâncer HospitalUNIFESP, Rheumatology DivisionFAPESP: 02/2446-1SciEL

    Fast calculation of spectral optical properties and pigment content detection in human normal and pathological kidney

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    A fast calculation method was used to obtain the spectral optical properties of human normal and pathological (chromophobe renal cell carcinoma) kidney tissues. Using total transmittance, total reflectance and collimated transmittance spectra acquired from ex vivo kidney samples, the spectral optical properties of both tissues, namely the absorption, the scattering and the reduced scattering coefficients, as well as the scattering anisotropy, dispersion and light penetration depth, were calculated between 200 and 1000 nm. Analysis of the mean ab sorption coefficient spectra of the kidney tissues showed that both contain melanin and lipofuscin, and that 83 % of the melanin in the normal kidney converts into lipofuscin in the pathological kidney.info:eu-repo/semantics/publishedVersio

    Genome Sequence of Corynebacterium pseudotuberculosis MB20 bv. equi Isolated from a Pectoral Abscess of an Oldenburg Horse in California.

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    The genome of Corynebacterium pseudotuberculosis MB20 bv. equi was sequenced using the Ion Personal Genome Machine (PGM) platform, and showed a size of 2,363,089 bp, with 2,365 coding sequences and a GC content of 52.1%. These results will serve as a basis for further studies on the pathogenicity of C. pseudotuberculosis bv. equi
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