2,456 research outputs found

    A systematic comparison of roundtrip software engineering approaches applied to UML class diagram

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    Model-based software engineering contemplates several software developments approaches in which models play an important role. One such approach is round-trip engineering. The objective of this paper is to benchmark the comparative analysis of the round-trip engineering capability of three modelling tools: Papyrus, Modelio and Visual Paradigm. The conclusions drawn throughout the paper will answer the question: How effective are current code generation tools for documenting application evolution? Throughout the discussion, we have pointed out several improvements that these UML modelling tools have recently brought to the discussion. We have also proposed some improvements that we consider desirable to improve Roundtrip Engineering approaches pointing out possible directions and solutions.info:eu-repo/semantics/publishedVersio

    SAMplus: adaptive optics at optical wavelengths for SOAR

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    Adaptive Optics (AO) is an innovative technique that substantially improves the optical performance of ground-based telescopes. The SOAR Adaptive Module (SAM) is a laser-assisted AO instrument, designed to compensate ground-layer atmospheric turbulence in near-IR and visible wavelengths over a large Field of View. Here we detail our proposal to upgrade SAM, dubbed SAMplus, that is focused on enhancing its performance in visible wavelengths and increasing the instrument reliability. As an illustration, for a seeing of 0.62 arcsec at 500 nm and a typical turbulence profile, current SAM improves the PSF FWHM to 0.40 arcsec, and with the upgrade we expect to deliver images with a FWHM of 0.34\approx0.34 arcsec -- up to 0.23 arcsec FWHM PSF under good seeing conditions. Such capabilities will be fully integrated with the latest SAM instruments, putting SOAR in an unique position as observatory facility.Comment: To appear in Proc. SPIE 10703 (Ground-based and Airborne Instrumentation for Astronomy VII; SPIEastro18

    Development of molecular and enzymatic kits for the detection of total coliforms and Escherichia coli in water samples

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    The drinking water is one of the main sources of infectious diseases. It is of major importance to keep a good water quality monitoring. The need for more rapid, sensitive and specific tests is essential; not only for water industry, but for a better public safety. Therefore, detection of microbial indicators of potential pathogens in water is the solution to the prevention and recognition of problems related to human health and safety. The main purpose of this work is to develop commercial kits for the detection of the extensively used as indicator organisms: Escherichia coli and total coliforms. An enzymatic method of detection of these microorganisms is being developed based on the enzymes β-Dglucuronidase and β-D-galactosidase, respectively. The results are visible in 18 h for 1 CFU. In order to achieve a higher level of sensitivity and specificity, molecular detection using the Polymerase Chain Reaction (PCR) technique is being investigated. Three primers were selected for identification of total coliforms, E. coli and E. coli with other enteric pathogens. At this moment, we achieved a sensitivity level of 676 CFU in 8 h, which is already a good achievement but there is still more research to be done in order to accomplish the 1 CFU detection

    Thermal contact resistance between two nanoparticles

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    We compute the thermal conductance between two nanoparticles in contact based on the Molecular Dynamics technique. The contact is generated by letting both particles stick together under van der Waals attractions. The thermal conductance is derived from the fluctuation-dissipation theorem and the time fluctuations of the exchanged power. We show that the conductance is proportional to the atoms involved in the thermal interaction. In the case of silica, the atomic contribution to the thermal conductance is in the range of 0.5 to 3 nW.K-1. This result fits to theoretical predictions based on characteristic times of the temperature fluctuation. The order of magnitude of the contact conductance is 1 \mu W.K-1 when the cross section ranges from 1 to 10nm2

    Atividade física de lazer entre as gestantes da coorte de nascimentos de Pelotas de 2004

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    OBJECTIVE: Physical activity during pregnancy is a poorly investigated subject on population level. The study aimed to describe duration, type and frequency of leisure-time physical activity during pregnancy, and to explore its associated factors. METHODS: A population-based study was carried out during 2004 in Southern Brazil. A total of 4,471 mothers were interviewed soon after delivery. Physical activity was measured using a questionnaire, developed for the study. Results were obtained by Poisson regression. RESULTS: In the sample, 14.8% of women reported to engage in some type of physical activity prior to pregnancy and 12.9% during pregnancy. In the first trimester, 10.4% of all mothers engaged in some type of physical activity; 8.5% in the second trimester and 6.5% in the third trimester. Only 194 mothers (4.3%) were active during the whole pregnancy. In the adjusted analysis, leisure-time physical activity was positively associated with schooling, physical activity advice during prenatal care, and family income (pOBJETIVO: A atividade física durante a gestação é pouco estudada em nível populacional. O objetivo do estudo foi descrever a duração, tipo e freqüência de atividade física de lazer durante a gravidez e explorar fatores associados. MÉTODOS: Estudo de base populacional, realizado durante o ano de 2004 em Pelotas, RS, Brasil. Logo após o parto, 4.471 mães foram entrevistadas. Utilizou-se questionário, desenvolvido para o estudo, para verificar a atividade física de lazer. Os resultados foram obtidos por regressão de Poisson. RESULTADOS: Antes da gravidez, 14,8% das mulheres relataram algum tipo de atividade física de lazer e durante, 12,9%. No primeiro trimestre, 10,4% de todas as mães fizeram alguma atividade física de lazer; no segundo, 8,5% e no terceiro, 6,5%. Apenas 194 mães (4,3%) foram ativas durante toda a gestação. Na análise ajustada, atividade física de lazer esteve positivamente associada com escolaridade, aconselhamento para atividade física durante o pré-natal e renda familiar (

    An open and parallel multiresolution framework using block-based adaptive grids

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    A numerical approach for solving evolutionary partial differential equations in two and three space dimensions on block-based adaptive grids is presented. The numerical discretization is based on high-order, central finite-differences and explicit time integration. Grid refinement and coarsening are triggered by multiresolution analysis, i.e. thresholding of wavelet coefficients, which allow controlling the precision of the adaptive approximation of the solution with respect to uniform grid computations. The implementation of the scheme is fully parallel using MPI with a hybrid data structure. Load balancing relies on space filling curves techniques. Validation tests for 2D advection equations allow to assess the precision and performance of the developed code. Computations of the compressible Navier-Stokes equations for a temporally developing 2D mixing layer illustrate the properties of the code for nonlinear multi-scale problems. The code is open source

    Influence of recycled plastics on the mechanical behaviour of bituminous mistures for highway surface layers

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    Europe is one of the largest producers of plastics in the world, with an annual turnover of over 350 billion euros, making it a strategic industrial sector as the global consumption of plastics increases. However, plastic is nowadays considered a serious environmental problem as it represents a large share of the world’s waste generation, with Europe being one of the largest sources of plastic waste exports. Therefore, the transition to a circular economy for plastics must be driven by Europe in order not to jeopardize the economic and environmental future of the plastics sector on the continent. Thus, it is crucial to investigate the feasibility of using recycled plastics in different applications, especially in the three main end-use markets for plastics (packaging, construction and automotive). In the construction sector, the use of plastics in road and highway construction and rehabilitation is currently being investigated due to the high potential for high-value applications and high raw material consumption. However, more knowledge is needed to make recycled plastic a common solution for road surfacing. The current study was promoted by BRISA, which was ranked the most sustainable highway operator in Europe for the third time in 2021. It aims to contribute to European efforts to investigate the feasibility (ongoing study: mechanical, functional, and environmental laboratory and field evaluation) of using recycled plastic in the production of bituminous mixtures for highway pavements in Portugal, without limiting the recyclability of bituminous mixtures. The present work focuses on the influence of recycled plastics on the water sensitivity and deformation susceptibility of bituminous mixtures under load. To perform the experimental study, the following materials were used: two bituminous mixtures with different types of coarse and fine aggregates (granodiorites and granites); a bitumen (PMB 45/80-65); a filler (limestone); and five recycled plastic additives (mainly consisting of LDPE, HDPE, LLDPE and PP, which represent about 50% of the plastics produced in Europe). The results were statistically analysed together with results of other studies on the volumetric and Marshall properties of the specimens. The results show an overall improvement in resistance to permanent deformation, without a significant benefit in water resistance. However, efforts to validate performance regarding fatigue, ageing resistance, pollutant emissions during production, placement and in service pavements are ongoing. In the statistical analysis, the ratio between binder film thickness and porosity (BFT/Vv) showed a statistically significant strong correlation with the performance indicators for resistance to permanent deformation.info:eu-repo/semantics/submittedVersio

    An improved microbiological water quality monitoring enzymatic kit for commercial use

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