4,290 research outputs found
On the Evaluation of the Mechanical Behaviour of Structural Glass Elements
Glass can be considered to be a high-technology engineering material with a
multifunctional potential for structural applications. However, the conventional approach to the use
of glass is often based only on its properties of transparency and isolation. It is thus highly
appropriate and necessary to study the mechanical behaviour of this material and to develop
adequate methods and models leading to its characterisation. It is evident that the great potential of
growth for structural glass applications is an important opportunity of development for the glass
industry and the building/construction sectors. The work presented in this paper is a reflection of
this conclusion. The authors shortly present the state-of-the-art on the application of glass as a
structural element in building and construction, and refer to other potential fields of application and
available glass materials. The experimental procedures and methods adopted in three-point bending
tests performed on 500 × 100 [mm2] float, laminated and tempered glass specimens with
thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical
strength and stiffness of glass for structural applications. This work contributes to a deeper
knowledge of the properties of this material
Reforço de edifícios existentes de betão armado com contraventamentos metálicos
Foi calibrado um modelo numérico refinado para a reprodução do comportamento de estruturas existentes de betão armado, e do seu reforço por contraventamento, face a solicitações sísmicas. Estes modelos foram calibrados com base numa série de ensaios
Estratégias de optimização numérica para o cálculo não-linear de estruturas reticuladas
A realização de análises pelo Método dos Elementos Finitos baseadas em modelos
de comportamento elásticos e lineares resulta, em determinadas aplicações, em previsões limitadas do comportamento real das estruturas. No trabalho que aqui se apresenta descreve-se um modelo de optimização aplicável ao cálculo numérico do comportamento não-linear de estruturas reticuladas. O modelo descrito actua directamente sobre um incremento de
força (carga) aplicado na estrutura. O algoritmo desenvolvido e implementado baseia-se numa análise da evolução de algumas das variáveis de estado do problema, criteriosamente seleccionadas. Com o algoritmo proposto é possível ajustar, de forma automática e contínua,
o passo de cálculo de modo a que este se torne suficientemente pequeno em fases do processo em que ocorram variações mais rápidas da rigidez tangente do material, não se perdendo precisão no cálculo. Alternativamente, quando tal não acontecer, o tamanho do incremento pode ser progressivamente aumentado, por forma a acelerar a evolução do cálculo e, consequentemente, aumentar a relação qualidade/custo dos resultados obtidos. O modelo é descrito e testado, mostrando-se as vantagens da sua utilização na análise não-linear do comportamento de estruturas reticuladas
Histopathological diagnosis of onychomycosis using calcofluor white (CW) stain : Comparison with PAS staining of nail sections
[Objective] The aim of this work is to compare results from PAS
routine staining and CW stain on histopathological evaluation of
onychomycosis. [...
Regular or random: a discussion on SPH initial particle distribution
Smoothed Particle Hydrodynamics (SPH) has been used to model a variety of objects and for a number of applications in engineering and science. These have ranged from astrophysicstofluidandsolidmechanicsproblems. Muchresearchhasbeendedicatedtoforming a better understanding of the SPH method. As a consequence, new numerical techniques have been developed in order to overcome some of its difficulties and limitations. Nonetheless, there is still a gap in information concerning the impact of the initial particle distribution on the effectiveness of the SPH method. With this in mind, a review of existing recommendations for SPH initial configurations has been conducted in this paper. In addition to this, a numerical exampleispresentedwhichisbasedontheclassical2-Dliddrivencavityproblem,whereinthe upperboundaryexertsahorizontalshearforceonthefluidinsidethecavity. Thevelocityofthe lid is v = 10−3 m/s and the cavity is square with length l = 1x10−3 m. The fluid was modelled with a density ρ = 1000 kg/m3, a viscosity µ = 10−3 kg/ms) (Re = 1). These parameters were held constant for all consequent comparisons. The number of particles is varied from (20 × 20) to (80 × 80). The initial distribution is modelled in three different ways: (i) regular, (ii) pseudo-random (with a 30% random deviation from the regular grid) and (iii) fully random. Theeffectivenessofeachinitialparticledistributionisassessedaccordingtothefieldvelocities and horizontal and vertical centreline velocity profiles. The impact of the initial particle distribution is highlighted and compared against a reference CFD result, and recommendations and conclusions are drawn for the SPH method
Tuned liquid dampers simulation for earthquake response control of buildings
This paper is focused on the study of an earthquake protection system, the Tuned Liquid Damper (TLD), which
can, if adequately designed, reduce earthquake demands on buildings. This positive effect is accomplished taking
into account the oscillation of the free surface of a fluid inside a tank (sloshing). The behaviour of an isolated
Tuned Liquid Damper, subjected to a sinusoidal excitation at its base, with different displacement amplitudes,
was studied by finite element analysis. The efficiency of the TLD in improving the seismic response of an existing building, representative of modern architecture buildings in southern European countries was also evaluated based on linear dynamic analyses
Avaliação de nova variedade de milho-doce quanto a caracteres expressos em fase de milho-verde nas condições de Sete Lagoas.
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