Institution
Instituto Superior Técnico
Education•
About: Instituto Superior Técnico is a based out in . It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 10085 authors who have published 30226 publications receiving 667524 citations. The organization is also known as: IST & Instituto Superior Tecnico.
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Papers
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TL;DR: In this article, the main types of both homogeneous and supported vanadium catalysts and the most efficient catalytic systems in different reactions are presented and compared, and the proposed mechanisms of various catalytic oxidation processes are also outlined.
195 citations
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Instituto Superior Técnico1, Harvard University2, Martin Luther University of Halle-Wittenberg3, University of Porto4, Higher University of San Andrés5, Zoological Society of London6, United States Geological Survey7, American Museum of Natural History8, The Lodge9, University of Hamburg10, University of Toulouse11, Helmholtz Centre for Environmental Research - UFZ12, University of Lisbon13, Butterfly Conservation14
TL;DR: In this article, the authors classify sources of primary observations into four types: extensive and intensive monitoring schemes, ecological field studies and satellite remote sensing, and demonstrate the links between data sources, EBVs and indicators and discuss how different sources of biodiversity observations can be harnessed to inform EBVs.
194 citations
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TL;DR: In this paper, the problem of optimal structural reinforcement for a critical load criterion is formulated as a linearized eigenvalue problem assuming only material effective properties and macroscopic instability modes.
Abstract: Material based models for topology optimization of linear elastic solids with a low volume constraint generate very slender structures composed mainly of bars and beam elements. For this type of structure the value of the buckling critical load becomes one of the most important design criteria and so its control is very important for meaningful practical designs. This paper tries to address this problem, presenting an approach to introduce the possibility of critical load control into the topology optimization model. Using the material based formulation for topology design of structures, the problem of optimal structural reinforcement for a critical load criterion is formulated. The stability problem is conveniently reduced to a linearized eigenvalue problem assuming only material effective properties and macroscopic instability modes. The respective optimality criteria are presented by introducing the Lagrangian associated with the optimization problem. Based on this Lagrangian a first-order method is used as a basis for the numerical update scheme. Two numerical examples to validate the developments are presented and analysed.
194 citations
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TL;DR: In this paper, the influence of the processing conditions on the microstructure and abrasive wear behavior of a NiCrBSi hardfacing alloy is analysed, and the results indicate that it is important to have good microstructural control of this material, in order to obtain coatings with an optimized and homogeneous tribological behaviour.
Abstract: In this work, the influence of the processing conditions on the microstructure and abrasive wear behaviour of a NiCrBSi hardfacing alloy is analysed. The hardfacing alloy was applied in the form of coatings onto a mild steel substrate (Fe–0.15%C) by different techniques: laser cladding (LC) and flame spraying (FS) combined with surface flame melting (SFM). In both cases, the appropriate selection of the process parameters enabled high-quality, defect-free NiCrBSi coatings to be obtained. The microstructure of the coatings was analysed by scanning electron microscopy (SEM), with attached energy dispersive spectroscopy (EDS) microprobe, and by X-ray diffraction (XRD). Their tribological properties were evaluated by micro-scale ball cratering abrasive wear tests using different abrasives: diamond, SiC and WC. Microstructural characterisation showed that both coatings exhibit similar phases in their microstructure, but the phases present differ in morphology, size distribution and relative proportions from one coating to another. Wear tests showed that in three-body abrasive conditions, despite these microstructural differences, the wear behaviour is comparable for both coatings. Conversely, in two-body wear conditions with diamond particles as the abrasive, it was observed that the specific wear rate of the material is sensitive to microstructural changes. This fact is particularly apparent in LC coatings, in which the zones of the layers with higher proportions of very small hard particles present a lower wear resistance. These results indicate that it is important to have good microstructural control of this material, in order to obtain coatings with an optimized and homogeneous tribological behaviour.
194 citations
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TL;DR: In this paper, the generalized Chaplygin gas (GCG) model was used to study the dark energy-dark matter (XCDM) unification approach in the context of the GCG model.
Abstract: We use the most recent Type Ia supernova data in order to study the dark energy–dark matter (XCDM) unification approach in the context of the generalized Chaplygin gas (GCG) model. Rather surprisingly, we find that data allow models with α > 1. We have studied how the GCG adjusts flat and non-flat models, and our results show that GCG is consistent with a flat case up to 68 per cent confidence level. Actually this holds even if one relaxes the flat prior assumption. We have also analysed what one should expect from a future experiment such as the Supernova/Acceleration Probe (SNAP). We find that there is a degeneracy between the GCG model and an XCDM model with a phantom-like dark energy component.
193 citations
Authors
Showing all 10288 results
Name | H-index | Papers | Citations |
---|---|---|---|
Joao Seixas | 153 | 1538 | 115070 |
A. Gomes | 150 | 1862 | 113951 |
Amartya Sen | 149 | 689 | 141907 |
António Amorim | 136 | 1477 | 96519 |
Joao Varela | 133 | 1411 | 92438 |
Pietro Faccioli | 132 | 1378 | 89795 |
João Carvalho | 126 | 1278 | 77017 |
Pedro Jorge | 124 | 776 | 68658 |
Pedro Silva | 124 | 961 | 74015 |
A. De Angelis | 118 | 534 | 54469 |
Hermine Katharina Wöhri | 116 | 629 | 55540 |
Helena Santos | 114 | 1058 | 54286 |
P. Conde Muiño | 109 | 558 | 56133 |
Joao Saraiva | 107 | 519 | 53340 |
J. N. Reddy | 106 | 926 | 66940 |