Encontrados 29 documentos, a visualizar página 1 de 3
Potencial alelopático de Annona crassiflora: efeitos sobre plantas daninhas
Inoue,M.H.; Santana,D.C.; Souza Filho,A.P.S.; Possamai,A.C.S.; Silva,L.E.; Pereira,M.J.B.; Pereira,K.M.A alelopatia pode oferecer novas substâncias químicas com propriedades herbicidas menos prejudiciais ao ambiente e ao homem do que os sintéticos em uso na atual agricultura. Nesse contexto, foi avaliado o efeito de extratos de Annona crassiflora sobre a germinação e o desenvolvimento de Brachiaria brizantha, Euphorbia heterophylla e Ipomoea grandifolia, bem como o efeito do extrato mais promissor sobre a soja (...
A study protocol to evaluate the relationship between outdoor air pollution and...
Ribeiro, M.C.; Pereira, M.J.; Soares, A.; Branquinho, C.; Augusto, S.; Llop, E.; Fonseca, S.; Nave, J.G.; Tavares, A.B.; Dias, Carlos Matias; Silva, A.Background - The present study protocol is designed to assess the relationship between outdoor air pollution and low birth weight and preterm births outcomes performing a semi-ecological analysis. Semi-ecological design studies are widely used to assess effects of air pollution in humans. In this type of analysis, health outcomes and covariates are measured in individuals and exposure assignments are usually b...
Paper surface diffraction to characterise the fibre orientation distribution
Pereira, M.J.T.; Fiadeiro, P.T.; Silvy, J.Many paper mills use ultrasonic techniques to measure the Tensile Stiffness Index, TSI, of the paper sheet. They then assume that the TSI value is the same as the fibre orientation anisotropy. This is true if the paper is allowed to dry without any internal tension or elongation, but does not apply to paper manufactured in a paper machine. The paper machine introduces tension and elongation as soon as the fibre...
Diffusion of the Laser Radiation to Characterise the Paper Fibre Orientation an...
PEREIRA, M.J.T.; P.T.Fiadeiro; F.M.P.B.FerreiraThis work concerns the determination of fiber orientation in the paper sheet and possibly the mass density distribution. Both parameters strongly influence the quality of the paper for end uses in printing and converting. The measurement of such parameters is done using different approaches, most commonly indirectly from the determination of the paper's physical properties. The measurement and analysis of ...
The Surface Measurement of Fibre Orientation Anisotropy and Misalignment Angle ...
Pereira, M.J.T.; Fiadeiro, P.T.; Jesus, M.E.P.; Silvy, J. J.The dimensional stability in fibre webs mainly depends of the fibre anisotropy and its orientation on the surfaces. These parameters are influenced during the manufacturing process, where the length and type of the fibres is determinant. The web quality control, in general, is performed based on the measurement of these parameters in the bulk of the fibre webs. This paper presents an optical laser diffraction m...
O índice e a direcção de rigidez na quantificação da orientação das fibras no p...
PEREIRA, M.J.T.; P.T. FiadeiroAs técnicas ultra-sónicas encontram-se amplamente divulgadas na indústria do papel para medição do índice de rigidez (TSI) das folhas de papel. Para a indústria do papel o valor deste índice é assumido como sendo igual à anisotropia de orientação das fibras, o que acontece só quando a folha de papel é seca sem estar sujeita a tensões internas ou elongações. De forma a medir unicamente a anisotropia de orientaçã...
3-D Characterisation of Nonwoven Fabrics by means of an optical system
PEREIRA, M.J.T.; L. R. Salvado; P. T. Fiadeiro; J. SilvyThe characterisation of fabric structure by means of quantified parameters is essential for the control of the fabrication processes and the resulting properties of the nonwoven materials. Important parameters of the structure are the porosity, the mean pore size and the pore size distribution, the specific area of the texture, the fibres orientation the last one needing to be characterised in the three dimensi...
New method for the measurement of fibres orientation on the paper faces applied...
Pereira, M.J.T.; Costa, A.P.; Trindade, A.C.; Fiadeiro, P. T.; Silvy, J.; Tosio, J.M.SerraFor a given change in the humidity of a paper the hygro-instability of the sheet depends of two main factors: the sheet structural parameters which reflects its structure: the sheet porosity, the fibres orientation distribution mainly in the sheet plane and the variations of these parameters across the paper sheet thickness. the water reactivity of the components of the paper sheet which depends mainly of t...
Structure of papers and Nonwovens
PEREIRA, M.J.T.; A.P. Costa; R. Salvado; J. Silvy; P.T. FiadeiroWe characterise the structure of fibrous materials: papers and nonwovens by diffraction and transmission of light. This allows the measurement of the fibres orientation distribution of the sample as a whole or for the surfaces using replicas. Applications of the methods are demonstrated in the case of paper for the control of the curl tendency and for two kinds of nonwoven materials, one used in the tailoring o...
Phenotypic variation of Fucus ceranoides, F. spiralis and F. vesiculosus in a t...
Cairrão, E.; Pereira, M. J.; Morgado, F.; Nogueira, A. J. A.; Guilhermino, L.; Soares, A. M. V. M.Brown algae includes several species of Fucus, reported both in the tidal and intertidal zones of cold and temperate regions. Environmental parameters induce wide biological variability in intertidal algae, manifested by alterations at several levels, and this has lead to the failure of some reports to discriminate between closely related taxa, particularly Fucus species. As the genus Fucus is widely represente...
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