7,853 research outputs found
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
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
Sensory evaluation of origami tessellations patterns in surface design
O estudo busca avaliar os nĂveis de conforto sensorial visual e tátil provido do origami tessellations voltado para o design de superfĂcie. Com base nas metodologias de análise sensorial, foi aplicado um questionário prático a um grupo de oito especialistas e quatro amostras de dobras. O objetivo Ă© identificar os padrões mais recomendados para o design de superfĂcie 3D e possĂvel aplicação ao vestuário.The study seeks to assess the levels of visual and tactile sensory comfort provided by the origami tessellations focused to the surface design. Based on the sensory analysis methodologies, a practical questionnaire was applied to a group of eight specialists and four folding samples. The goal is to identify the most recommended patterns for 3D surface design and possible application to clothing.info:eu-repo/semantics/publishedVersio
Biologia da polinização da castanheira-do-brasil (Bertholletia excelsa Bonpl., LECYTHIDACEAE) em Tomé-Açu, Pará.
A castanheira-do-brasil (Bertholletia excelsa Bonpl.) é uma espécie arbórea nativa da Amazônia. Este estudo teve como objetivo investigar a biologia floral e os requerimentos de polinização dessa espécie em um Sistema Agroflorestal (SAF), em Tomé-Açu/PA, nos anos de 2010 e 2011. Chegou-se às flores através de torres de observação de 12 a 20 metros de altura. Caracterizou-se: a antese; duração da floração; receptividade de estigma; viabilidade de pólen; localização dos osmóforos; volume e % de açúcar do néctar; comportamento e identificação de visitantes florais; e o sistema reprodutivo, através de testes de polinização controlada: autopolinização espontânea (AE, n=540/1.672) e induzida (AI, n=657/1.566); xenogamia (XE, n=880/1.716) e geitonogamia (GE, n=742/1.443). O controle foi realizado por polinização livre (PL, n=564/2.343), dados de 2010/2011, respectivamente. A floração ocorreu nos meses de outubro a janeiro. A antese variou entre as árvores entre 01:00h e 05:30h. De 07:00h às 11:00h o estigma está receptivo e o pólen viável. O néctar tem maior concentração de açúcares às 8:30h e volume crescente de 06:30 às 12:30h. Registrou-se a formação de 29 frutos em 2010: AE=9; AI=7; XE=10; GE=2 e PL=1. Em 2011, apenas dois frutos: XE=1 e PL=1. Nas flores, coletou-se 64 insetos entre as ordens Hymenoptera; Hemiptera; e Coleoptera. O polinizador efetivo foi Xylocopa frontalis
Topological insulator particles as optically induced oscillators: towards dynamical force measurements and optical rheology
We report the first experimental study upon the optical trapping and
manipulation of topological insulator (TI) particles. By virtue of the unique
TI properties, which have a conducting surface and an insulating bulk, the
particles present a peculiar behaviour in the presence of a single laser beam
optical tweezers: they oscillate in a plane perpendicular to the direction of
the laser propagation, as a result of the competition between radiation
pressure and gradient forces. In other words, TI particles behave as optically
induced oscillators, allowing dynamical measurements with unprecedented
simplicity and purely optical control. Actually, optical rheology of soft
matter interfaces and biological membranes, as well as dynamical force
measurements in macromolecules and biopolymers, may be quoted as feasible
possibilities for the near future.Comment: 6 pages, 5 figures. Correspondence and requests for Supplementary
Material should be addressed to [email protected]
Formatação de dados usando a ferramenta Velocity.
Origem e caracterĂsticas; Arquitetura. Funcionamento e esquema de uso. Linguagem VTL. Aplicação Java. Configuração da Velocity. Trecho de cĂłdigo fonte Java exemplificando o uso da ferramenta Velocity. Trecho de template em VTL relativo ao item anterior.bitstream/CNPTIA/9874/1/comuntec20.pdfAcesso em: 29 maio 2008
Estudo de expert system shells para o ambiente de diagnose remota.
Conceitos: sistemas especialistas, Expert Sysyem Shell, Diagnose remota, AppLets, ServLets. Ambiente de diagnose remota e motivação de mudança. Ferramentas estudadas: WebLS. JESS, CLIPS, WebCLIPS, quadros comparativos.bitstream/CNPTIA/9215/1/DOCUMENTO7int.pdfAcesso em: 29 maio 2008
Riqueza de espécies de abelhas euglossina (Hymenoptera, apidae) em dois fragmentos florestais inseridos no arco do desmatamento amazônico, estado do Pará.
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