Finite element analysis of the ECT test on mode III interlaminar fracture of carbon-epoxy composite laminates

In this work a parametric study of the Edge Crack Torsion (ECT) specimen was performed in order to maximize the mode III component (GIII) of the strain energy release rate for carbon-epoxy laminates. A three-dimensional finite element analysis of the ECT test was conducted considering a [90/0/(+45/-45)2/(-45/+45)2/0/90]S lay-up. The main objective was to define an adequate geometry to obtain an almost pure mode III at crack front. The geometrical parameters studied were specimen dimensions, distance between pins and size of the initial crack. The numerical results demonstrated that the ratio between the specimen length and the initial crack length had a significant effect on the strain energy release rate distributions. In almost all of the tested configurations, a mode II component occurred near the edges but it did not interfere significantly with the dominant mode III state.FCT - POCTI/EME/45573/200

A new data reduction scheme to obtain the mode II fracture properties of Pinus Pinaster wood

In this work a numerical study of the End Notched Flexure (ENF) specimen was performed in order to obtain the mode II critical strain energy released rate (GIIc) of a Pinus pinaster wood in the RL crack propagation system. The analysis included interface finite elements and a progressive damage model based on indirect use of Fracture Mechanics. The difficulties in monitoring the crack length during an experimental ENF test and the inconvenience of performing separate tests in order to obtain the elastic properties are well known. To avoid these problems, a new data reduction scheme based on the equivalent crack concept was proposed and validated. This new data reduction scheme, the Compliance-Based Beam Method (CBBM), does not require crack measurements during ENF tests and additional tests to obtain elastic properties.FCT - POCTI/EME/45573/200

A new methodology for the characterization of mode II fracture of pinus pinaster wood

In this study, the End Notched Flexure (ENF) fracture test was used to obtain the mode II Rcurve of the Pinus pinaster wood in the RL crack propagation system. The test method was numerically and experimentally analyzed. In the numerical study, three (3D) and twodimensional (2D) finite element analyses were conducted to determine the mode II critical strain energy release rate (GIIc) and the respective R-curve. Firstly, the 3D analysis was performed in order to obtain the strain energy release rates distributions at the crack tip, and consequently, to identify the presence of spurious fracture modes that could affect the measured GIIc. The P-δ-a values determined from the 3D model were compared with the same values obtained from the 2D model. The main objective was to validate the 2D model, which is computationally less expensive. On the other hand, measurement of the crack length in the ENF test is quite difficult in wood because crack tends to close during propagation. To avoid this experimental problem a Compliance-Based Beam Method (CBBM), based on equivalent crack approach, is proposed. Moreover, this method does not require additional experimental tests to obtain the elastic properties. Experimental tests were also executed in order to verify the numerical results. The aim is to introduce the CBBM as a standard data reduction scheme in order to measure the GIIc value

A new gypsy-like retroelement family in Vitis vinifera

As a major part of most plant genomes, retrotransposons are distributed throughout the plant genome ubiquitously with high copy number and extensive heterogeneity. Various retrotransposon families with distinct structures differ in their distribution and roles among divergent plant species, due to unforeseen transposition activities.We had performed in silico analysis of the Vitis vinifera 'Pinot Noir' genome to search for gypsy type retroelements homologues to the one identified in Pinus radiata (IFG7) and P. pinaster (PpRT1) and in Quercus suber (Corky). We intended to see the existence and structure of gypsy-like retroelements homologues in the Vitis genome as well as the existence of integration site preference. From all data and to perform a deeper analysis we chose 36 complete sequences copies in the Vitis genome. We used three genetic distance corrections, additional to p-distance to estimate retroelements insertion time and reverse transcriptase, integrase and LTR (Long Terminal Repeat) sequences to establish a phylogeny and to see the contributions of different regions according to the evolutionary rates. We found three elements with identical LTRs and two old elements that revealed recent and very old insertions as well as insertions inside other retroelements. Additionally, we found no preference for the integration site as shown by the different target site repeat for each element.

Signature of stripe pinning in optical conductivity

The response of charge stripes to an external electric field applied perpendicular to the stripe direction is studied within a diagrammatic approach for both weak and strong pinning by random impurities. The sound-like mode of the stripes described as elastic strings moves to finite frequency due to impurity pinning. By calculating the optical conductivity we determine this characteristic energy scale for both a single stripe and an array of interacting stripes. The results explain the anomalous far-infrared peak observed recently in optical-conductivity measurements on cuprates.Comment: Revised version, to appear in Phys. Rev.

Non-Newtonian fluid flow through three-dimensional disordered porous media

We investigate the flow of various non-Newtonian fluids through three-dimensional disordered porous media by direct numerical simulation of momentum transport and continuity equations. Remarkably, our results for power-law (PL) fluids indicate that the flow, when quantified in terms of a properly modified permeability-like index and Reynolds number, can be successfully described by a single (universal) curve over a broad range of Reynolds conditions and power-law exponents. We also study the flow behavior of Bingham fluids described in terms of the Herschel-Bulkley model. In this case, our simulations reveal that the interplay of ({\it i}) the disordered geometry of the pore space, ({\it ii}) the fluid rheological properties, and ({\it iii}) the inertial effects on the flow is responsible for a substantial enhancement of the macroscopic hydraulic conductance of the system at intermediate Reynolds conditions. This anomalous condition of ``enhanced transport'' represents a novel feature for flow in porous materials.Comment: 5 pages, 5 figures. This article appears also in Physical Review Letters 103 194502 (2009

The MUSE 3D view of feedback in a high-metallicity radio galaxy at z = 2.9

We present a detailed study of the kinematic, chemical and excitation properties of the giant Ly$\alpha$ emitting nebula and the giant \ion{H}{I} absorber associated with the $z = 2.92$ radio galaxy MRC 0943--242, using spectroscopic observations from VLT/MUSE, VLT/X-SHOOTER and other instruments. Together, these data provide a wide range of rest-frame wavelength (765 \AA$\,$ -- 6378 \AA$\,$ at $z = 2.92$) and 2D spatial information. We find clear evidence for jet gas interactions affecting the kinematic properties of the nebula, with evidence for both outflows and inflows being induced by radio-mode feedback. We suggest that the regions of relatively lower ionization level, spatially correlated with the radio hotspots, may be due to localised compression of photoionized gas by the expanding radio source, thereby lowering the ionization parameter, or due to a contribution from shock-heating. We find that photoionization of super-solar metallicity gas ($Z/Z_{\odot}$ = 2.1) by an AGN-like continuum ($\alpha$=--1.0) at a moderate ionization parameter ($U$ = 0.018) gives the best overall fit to the complete X-SHOOTER emission line spectrum. We identify a strong degeneracy between column density and Doppler parameter such that it is possible to obtain a reasonable fit to the \ion{H}{I} absorption feature across the range log N(\ion{H}{I}/cm$^{-2}$) = 15.20 and 19.63, with the two best-fitting occurring near the extreme ends of this range. The extended \ion{H}{I} absorber is blueshifted relative to the emission line gas, but shows a systematic decrease in blueshift towards larger radii, consistent with a large scale expanding shell.Comment: 25 pages, 18 figures, 10 tables. Accepted for publication in MNRAS. Published: 23 November 201

Sobrevivência de patógenos em grãos de milho tratados com produtos naturais.

Resumo: Diante da propriedade inibitória da canela (Cinnamomum zeylanicum) para gêneros fúngicos, este trabalho teve por objetivo avaliar a ação da canela em diferentes formas e dois tipos de aplicação na sanidade de grãos de milho naturalmente infectados com Penicillium spp., Rhizopus sp., Fusarium spp. e Aspergillus spp. Utilizaram-se oito tratamentos com extratos de canela em duas concentrações, duas formas de aplicação em dois lotes comerciais de grãos de milho. Os tratamentos foram T1: Testemunha absoluta, T2: Extrato aquoso de canela 5% (T0h) aplicado diretamente no papel germitest, T3: Extrato aquoso de canela 5% (T24h) aplicado diretamente no papel germitest, T4: Extrato etanólico de canela 1% aplicado diretamente no papel germitest, T5: Testemunha-imersão, T6: Extrato aquoso de canela 5% (T0h)-imersão, T7: Extrato aquoso de canela 5% (T24h)-imersão, T8: Extrato etanólico de canela 1%-imersão. Os tratamentos que apresentaram melhores resultados para Penicillium spp. foram os que utilizaram os extratos aquosos de canela. O contato direto da canela em pó com o milho pode ocasionar a redução da incidência deste fungo em grãos armazenados. Para Fusarium spp., o extrato aquoso de canela a 5% aplicado em imersão reduziu em 52% incidência fúngica. O mesmo extrato em maiores concentrações poderá conferir um percentual maior de inibição, podendo alcançar a inibição total. Novos testes com número maior de lotes e concentrações do extrato são necessários para que os resultados sejam confirmados. Abstract: The aim of this work was to evaluate the effect of cinnamon extracts, at two technical of application on healthy of maize grains naturally infected with Penicillium spp., Rhizopus sp., Fusarium spp. and Aspergillus spp.. Eight treatments using two kinds of cinnamon extracts on two concentrations, two application types on two commercial maize lots. Treatments used were T1: witness (distilled water), T2: cinnamon aqueous extract 5% (T0h) applied directly on Germitest paper; T3: cinnamon aqueous extract 5% (T24h) applied directly on Germitest paper 24 hours after its prepare; T4: ethanolic cinnamon extract 1% applied directly on Germitest paper; T5: witness (distilled water - immersion), T6: cinnamon aqueous extract 5% (T0h) ? immersion; T7: cinnamon aqueous extract 5% (T24h) ? immersion; T8: ethanolic cinnamon extract 1% - immersion. Treatments that showed better results for Penicillium spp. were the aqueous cinnamon extracts. Direct contact of cinnamon powder with maize grains can reduce the incidence of this fungus on stored grains. For Fusarium spp., cinnamon aqueous extract 5% applied by immersion reduced the incidence of this fungus at 52%. The same extract, on higher concentrations can result a higher inhibition perceptual and can obtain total inhibition of Fusarium spp. on maize grains Another tests with higher number of lots and extracts concentrations are need to confirm these results