Non-singular inflation with vacuum decay

On the basis of a semi-classical analysis of vacuum energy in an expanding spacetime, we describe a non-singular cosmological model in which the vacuum density decays with time, with a concomitant production of matter. During an infinitely long period we have an empty, inflationary universe, with H \approx 1. This primordial era ends in a fast phase transition, during which H and \Lambda decrease to nearly zero in a few Planck times, with release of a huge amount of radiation. The late-time scenario is similar to the standard model, with the radiation phase followed by a long dust era, which tends asymptotically to a de Sitter universe, with vacuum dominating again. An analysis of the redshift-distance relation for supernovas Ia leads to cosmological parameters in agreement with other current estimations.Comment: Work presented at IRGAC 2006, Barcelona, July 11-15 2006. To appear in a special issue of Journal of Physics

THE APPLICATION OF THE BOUNDARY ELEMENT METHOD TO SOLVE VISCOUS FLOW PROBLEMS BASED ON PRIMITIVE VARIABLES FORMULATION

The boundary element method is applied to the solution of incompressible fluid flow problems governed by the continuity and Navier-Stokes equations. The differential equations are transformed into integral equations. Indication of the transformation is given in detail. Application to simple flow cases such as the driven cavity and forward facing step is presented. Convergence difficulties are indicated, which have limited the applications to flows of low Reynolds numbers.

Esterilização de suco de abacaxi por microfiltração

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Ergonomic design intervention in a coating production area

The aim of this study is to redesign two workstations in a PVD coating production area, considering productivity and ergonomic aspects. Through the elimination of wastes such as unnecessary movements and transportations and by reducing the awkward postures as arm flexion larger than 45º, the productivity in the loading and unloading workstations increased 9% and 5%, respectively, and the ergonomic risk was improved from medium to acceptable. RULA was the chosen method to evaluate the ergonomic situation and anthropometric studies were performed to find the ideal ergonomic solution. This study shows the importance to consider ergonomic conditions when designing or redesigning a workstation in order to get effective productivity improvements.(undefined)info:eu-repo/semantics/publishedVersio

Developing intelligent environments with OSGi and JADE

Series: IFIP International Federation for Information ProcessingThe development of intelligent environments poses complex challenges, namely at the level of device heterogeneity and environment dynamics. In fact, we still lack supporting technologies and development approaches that can efficiently integrate different devices and technologies. In this paper we present how a recent integration of two important technologies, OSGi and Jade, can be used to significantly improve the development process, making it a more dynamic, modular and configurable one. We also focus on the main advantages that this integration provides to developers, from the Ambient Intelligence point of view. This work results from the development of two intelligent environments: VirtualECare, which is an intelligent environment for the monitorization of elderly in their homes and UMCourt, a virtual environment for dispute resolution.The work described in this paper is included in TIARAC - Telematics and Artificial Intelligence in Alternative Conflict Resolution Project (PTDC/JUR/71354/2006), which is a research project supported by FCT (Science & Technology Foundation), Portugal

Podridão parda da haste: avaliação de genótipos de soja, safra 2013/2014.

bitstream/item/114978/1/2014-Documentos-online-151-p47.pd

Failure mechanisms and surface roughness statistics of fractured Fontainebleau sandstone

In an effort to investigate the link between failure mechanisms and the geometry of fractures of compacted grains materials, a detailed statistical analysis of the surfaces of fractured Fontainebleau sandstones has been achieved. The roughness of samples of different widths W is shown to be self affine with an exponent zeta=0.46 +- 0.05 over a range of length scales ranging from the grain size d up to an upper cut-off length \xi = 0.15 W. This low zeta value is in agreement with measurements on other sandstones and on sintered materials. The probability distributions P(delta z,delta h) of the variations of height over different distances delta z > d can be collapsed onto a single Gaussian distribution with a suitable normalisation and do not display multifractal features. The roughness amplitude, as characterized by the height-height correlation over fixed distances delta z, does not depend on the sample width, implying that no anomalous scaling of the type reported for other materials is present. It is suggested, in agreement with recent theoretical work, to explain these results by the occurence of brittle fracture (instead of damage failure in materials displaying a higher value of zeta = 0.8).Comment: 7 page

Estádio mais adequado de manejo do milheto para fins de adubação verde.

O milheto [Pennisetum glaucum (L.) R. Brown] é uma opção importante dentre as espécies vegetais para adubação verde. É uma planta anual, forrageira de verão, de clima tropical, hábito ereto, porte alto, e pode atingir até 5 m de altura. Dentre as principais características do milheto ressaltam-se: tolerância à seca, capacidade em adaptar-se a diferentes solos, facilidade de produzir sementes e boa adaptação à mecanização. Essa espécie vem sendo utilizada com maior intensidade, no Cerrado, no período de safrinha (fevereiro a abril) e na primavera (agosto a outubro), como adubo verde e cobertura do solo para plantio direto e outras finalidades, por exemplo, na integração lavoura-pecuária (BURLE et al., 2006).bitstream/item/51825/1/COT-2011-171.pd

Classificação de genótipos de amendoim forrageiro com uso do método REML/BLUP.

A seleção de genótipos superiores em programas de melhoramento depende de uma adequada classificação dos mesmos. Espécies perenes de uso recente, como o amendoim forrageiro, utilizam como base genética para o melhoramento os acessos do banco ativo de germoplasma (BAG). Este estudo objetivou verificar o efeito do tamanho da população e do desbalanceamento na classificação de genótipos de amendoim forrageiro. Foram simulados valores fenotípicos de produção de matéria seca, com base em dados experimentais de ensaios conduzidos com acessos do BAG do Amendoim Forrageiro na Embrapa Acre. Simularam-se populações com 4, 10, 30 e 100 genótipos, com 0 e 20% de desbalanceamento, cujos dados foram analisados pelo método REML/BLUP. Foram calculados a Correlação de Spearman (CS) e o Quadrado Médio do Erro (QME) entre os valores genotípicos simulados e os preditos. As CS variaram de 0,76 a 0,93. As populações com quatro genótipos apresentaram as menores correlações (0,76 e 0,78) em comparação com as demais populações. Observou-se que com o aumento do número de genótipos, ocorreu um aumento da CS, chegando a 0,91 para a população com 30 genótipos e 0,93 para a população balanceada com 100 genótipos. O nível de desbalanceamento não teve impacto na CS, indicando que a classificação foi similar nas duas situações. Observou-se que o QME foi maior para as populações desbalanceadas, exceto para população com 30 genótipos. A classificação dos genótipos superiores com base em seus valores genotípicos preditos é prejudicada quando a população é pequena

Towards the use of machine learning algorithms to enhance the effectiveness of search strings in secondary studies

Devising an appropriate Search String for a secondary study is not a trivial task and identifying suitable keywords has been reported in the literature as a difficulty faced by researchers. A poorly chosen Search String may compromise the quality of the secondary study, by missing relevant studies or leading to overwork in subsequent steps of the secondary study, in case irrelevant studies are selected. In this paper, we propose an approach for the creation and calibration of a Search String. We chose three published systematic literature reviews (SLRs) from Scopus and applied Machine Learning algorithms to create the corresponding Search Strings to be used in the SLRs. Comparison of results obtained with those published in previous SLRs, show an increase of recall of revisions by up to 12%, with no loss of recall. To motivate future studies and replications, the tool implementing the proposed approach is available in a public repository, along with the dataset used in this paper.info:eu-repo/semantics/acceptedVersio