Finite element modelling and analysis of crack shape evolution in mode-I fatigue Middle Cracked Tension specimens

A numerical procedure was employed to study the shape evolution of fatigue cracks in Middle Cracked Tension specimens. This iterative procedure consists of a 3D finite element analysis to obtain the displacement field in the cracked body, calculation of stress intensity factors along crack front and definition of local crack advances considering the Paris law. Numerical predictions were compared with experimental crack shapes with a good agreement. The evolution of crack shape was analysed for different propagation conditions considering robust dependent parameters. Two main propagation stages were identified: an initial transient stage highly dependent on initial crack shape and a stable stage where the crack follows preferred paths. Mathematical models were proposed for transient and stable stages consisting of exponential and polynomial functions, respectively. The transition between both stages was defined considering two criteria: the rate of shape variation and the distance to stable shape. Finally, the crack shape change was linked with the distribution of stress intensity factor along crack front.http://www.sciencedirect.com/science/article/B6V2R-4RGFD3P-1/1/e08212c92d2476b00aceb521ee4e521

The Nova SBE University merchandising venture

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsThe objective of this Work Project is twofold: to create a research project on the opportunities for launching a Nova School of Business and Economics (Nova SBE) merchandise project; and the description of the planned strategy for this project. The objective of the research is to identify, validate and measure what opportunities lie within offering NOVA SBE merchandise. The objective of the strategy’s plan is to provide a guideline for the project, so it can start being implemented as soon as possible. This guideline will include recommendations regarding the product line, pricing and marketing in the short and long-term

Monitoramento da cultura da cana-de-açúcar utilizando a Transformada de Wavelet em séries temporais de dados EVI/MODIS.

O objetivo do trabalho foi realizar o monitoramento da cultura da cana-de-açúcar no noroeste do Estado de São Paulo, utilizando a Transformada de Wavelet em séries temporais de dados EVI/MODIS, do ano de 2005 a 2009.SBSR 2011

The serotonin 1A receptor modulates the social behaviour within groups of a cooperatively-breeding cichlid.

The neurotransmitter serotonin (5-HT) reduces aggressive behaviour in a number of vertebrates, and the 5-HT1A receptor is known to be involved in this regulation. However, the role of this receptor in the modulation of sociopositive behaviour remains largely unknown. Here we investigated the role of the 5-HT1A receptor in the regulation of aggressive, submissive and affiliative behaviour in the cooperatively-breeding cichlid Neolamprologus pulcher. In two experiments, we performed intramuscular injections of a 5-HT1A agonist (8-OH-DPAT) and antagonist (Way-100635) followed by recordings of social behaviour of injected fish within their social groups. We determined the concentrations and post-injection times when the drugs had the greatest effect on social behaviour. We recorded spontaneous social behaviour in both experiments. In the second experiment we also recorded behaviour after social groups received a territorial challenge by live presentations of either conspecifics or egg predators. The 5-HT1A agonist caused an increase in aggression and a decrease in submission and affiliation, whereas the antagonist had the opposite effects. Thus, the 5-HT1A receptor plays an important regulatory role not only for aggressive but also sociopositive behaviour

Predicting the critical density of topological defects in O(N) scalar field theories

O(N) symmetric $\lambda \phi^4$ field theories describe many critical phenomena in the laboratory and in the early Universe. Given N and $D\leq 3$, the dimension of space, these models exhibit topological defect classical solutions that in some cases fully determine their critical behavior. For N=2, D=3 it has been observed that the defect density is seemingly a universal quantity at T_c. We prove this conjecture and show how to predict its value based on the universal critical exponents of the field theory. Analogously, for general N and D we predict the universal critical densities of domain walls and monopoles, for which no detailed thermodynamic study exists. This procedure can also be inverted, producing an algorithm for generating typical defect networks at criticality, in contrast to the canonical procedure, which applies only in the unphysical limit of infinite temperature.Comment: 4 pages, 3 figures, uses RevTex, typos in Eq.(11) and (14) correcte

Taste panel quality evaluation of 'Hayward' kiwifruit of different origins

In Portugal, the regions of Entre-Douro e Minho and Beira Litoral have exceptional conditions for the production of good quality kiwifruit. However, demand exceeds local supply resulting in importation of kiwifruit from Italy, Chile and New Zealand. Taste panels were run in December, May and June to study the preferences of Portuguese consumers for 'Hayward' kiwifruit. In December, a comparison was made between kiwifruit from Portugal and Italy, in May between kiwifruit from Portugal and Chile and in June between kiwifruit from Portugal, Chile and New Zealand. Attributes assessed by panellists were: appearance, texture, flavour, sweetness and acidity. The same samples were analyzed for: weight, equatorial and longitudinal diameter, firmness, soluble solids (as measured by refractometer) and titratable acidity. In May, panellists preferred Portuguese kiwifruit, but in December and June the preference was not so clear. In December, Portuguese kiwifruit were not at the eating ripe stage and in June they were at the end of their storage life (bad appearance but better flavour, sweetness and texture)

Comparative Analysis of Fatigue Life Predictions in Lateral Notched Round Bars under Multiaxial Loading

The main objective of this study is to predict the multiaxial fatigue life for lateral notched round bars made of DIN 34CrNiMo6 high strength steel. In-phase bending-torsion tests for different stress amplitudes and different ratios of the normal stress to the shear stress were performed. Single torsion and single bending tests were also conducted for different stress amplitudes. In addition, the beach marking technique was used to mark crack fronts on fracture surfaces for the different loading paths studied. Experimental fatigue life was compared with predictions obtained by the Coffin-Manson model. The stress-strain state at the notch root was evaluated using the Theory of Critical Distances (TCD) and the Equivalent Strain Energy Density (ESED). Finally, a comparative analysis of the fatigue life predictions obtained by the two above-mentioned approaches was carried out. The former gave good results for higher lives but was too conservative for lower lives. The latter led to good correlations in the range studied here

Seleção de rizobactérias autóctones de feijoeiro para controle biológico da mela ou teia micélica (Thanatephorus cucumeris).

Neste trabalho, buscou-se selecionar in vitro, por teste de antibiose direta (AD) e por determinação de compostos voláteis (ComVo) e in vivo, em casa-de-vegetação 150 isolados de rizobactérias, obtidos de feijoeiros sadios, capazes de inibir o crescimento de T. cucumeris e, consequentemente, a severidade da doença nas plantas. Assim, nos testes in vitro, em antibiose Direta (AD), os isolados foram semeados em placa de Petri com meio Kado e Heskett, (cinco por placa). Após 24h/27 oC, estes foram mortos com luz ultra-violeta. No centro da placa, discos de micélio T. cucumeris foram depositados e quatro dias após, avaliou-se a presença de halos de inibição do fungo. Nos ensaios de compsotos voláteis (ComVo), o fungo foi depositado na tampa da placa contendo BDA e uma rizobactéria foi semeada no fundo da mesma contendo meio 523. A placa foi selada e levada para BOD por 72h/27oC. Avaliou-se a velocidade de crescimento e o diâmetro máximo de crescimento do fungo. Nos testes in vivo, sementes de feijoeiro foram microbiolizadas com suspensão de rizobactérias (A540nm=0,4) por 12h. Semeou-se estas em copos plásticos de 500 mL contendo solo de barranco e manteve-se estes em casa-de-vegetação. Como controle, sementes embebidas em água destilada estéril. Aos 21 após a emergência das plantas, estas foram pulverizadas com uma suspensão de micélio triturado previamente em liquidificador (1,0x105 hifas/mL-1). Quatro dias após avaliou-se a severidade da doença nas folhas por meio de escala diagramática de severidade. Dos 150 isolados testados, cpafro-004, cpafro-007, cpafro-018, cpafro-023 e cpafro-038 foram capazes de inibir em AD o crescimento de T.cucumeris (0,5; 0,5; 0,7; 0,1; 0,3 cm diâmetro médio do halo respectiv.) e 46 produziram ComVo, sendo Cpafro 41, 33 e 20 foram os melhores, com máximo de crescimento da colônia de 2,8; 3,2 e 3,4 de diâmetro respectivamente. Nos testes in vivo, cpafro-26, cprafro-90 e cpafro-60 reduziram a severiade da mela (9%, 11% e 13% de severidade respect.) quando comparados com o controle com água (67% de severidade). Estes resultados demonstram a potencialidade do uso de rizobactérias no controle da mela do feijoeiro