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.
Topics: Catalysis, Finite element method, Population, Black hole, Ionic liquid
Papers published on a yearly basis
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TL;DR: The results suggested that the RDG-FA theory is a reasonable approximation for optics of a wide range of fractal aggregates, considerably extending its domain of applicability.
Abstract: The range of validity of the Rayleigh–Debye–Gans approximation for the optical cross sections of fractal aggregates (RDG-FA) that are formed by uniform small particles was evaluated in comparison with the integral equation formulation for scattering (IEFS), which accounts for the effects of multiple scattering and self-interaction. Numerical simulations were performed to create aggregates that exhibit mass fractallike characteristics with a wide range of particle and aggregate sizes and morphologies, including xp = 0.01–1.0, |m − 1| = 0.1–2.0, N = 16–256, and Df = 1.0–3.0. The percent differences between both scattering theories were presented as error contour charts in the |m − 1|xp domains for various size aggregates, emphasizing fractal properties representative of diffusion-limited cluster–cluster aggregation. These charts conveniently identified the regions in which the differences were less than 10%, between 10% and 30%, and more than 30% for easy to use general guidelines for suitability of the RDG-FA theory in any scattering applications of interest, such as laser-based particulate diagnostics. Various types of aggregate geometry ranging from straight chains (Df ≈ 1.0) to compact clusters (Df ≈ 3.0) were also considered for generalization of the findings. For the present computational conditions, the RDG-FA theory yielded accurate predictions to within 10% for |m − 1| to approximately 1 or more as long as the primary particles in aggregates were within the Rayleigh scattering limit (xp ≤ 0.3). Additionally, the effect of fractal dimension on the performance of the RDG-FA was generally found to be insignificant. The results suggested that the RDG-FA theory is a reasonable approximation for optics of a wide range of fractal aggregates, considerably extending its domain of applicability.
214 citations
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TL;DR: Biotransformations allow the production of regio- and stereoselective compounds under mild conditions and have produced encouraging results, as discussed in this review.
214 citations
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TL;DR: In this article, the acceleration of charged particles to relativistic energies by plasma waves that are created by intense laser and particle beams is studied, and the underlying physics and the present status of high gradient and high energy plasma accelerators are presented.
Abstract: Studies of charged-particle acceleration processes remain one of the most important areas of research in laboratory, space and astrophysical plasmas. In this paper, we present the underlying physics and the present status of high gradient and high energy plasma accelerators. We will focus on the acceleration of charged particles to relativistic energies by plasma waves that are created by intense laser and particle beams. The generation of relativistic plasma waves by intense lasers or electron beams in plasmas is important in the quest for producing ultra-high acceleration gradients for accelerators. With the development of compact short pulse high brightness lasers and electron positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high acceleration gradients. These include the plasma beat wave accelerator mechanism, which uses conventional long pulse (~100 ps) modest intensity lasers (I ~ 1014–1016 W cm−2), the laser wakefield accelerator (LWFA), which uses the new breed of compact high brightness lasers ( 1018 W cm−2, the self-modulated LWFA concept, which combines elements of stimulated Raman forward scattering, and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches. In the ultra-high intensity regime, laser/particle beam–plasma interactions are highly nonlinear and relativistic, leading to new phenomena such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm−1 have been generated with particles being accelerated to 200 MeV over a distance of millimetre. Plasma wakefields driven by positron beams at the Stanford Linear Accelerator Center facility have accelerated the tail of the positron beam. In the near future, laser plasma accelerators will be producing GeV particles.
214 citations
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TL;DR: In this article, the characteristics and applications of optical glass ceramics are reviewed, with particular emphasis on rare-earth-doped transparent glass-ceramics for photonics, including search for new transparent glass ceramic compositions and the development of suitable methods to process such materials into functional devices.
214 citations
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TL;DR: In this paper, a systematic review of 119 publications, selected from 235, published over a period of 36 years from 1978 to 2014, relating to the effect on concrete compressive strength of the various aspects related to the use of recycled aggregates (RA) such as replacement level, size, origin, moisture content, exposure of the resulting concrete to different environmental conditions, use of chemical admixtures and additions, and strength development over time.
Abstract: This paper provides a systematic review of 119 publications, selected from 235, published over a period of 36 years from 1978 to 2014, relating to the effect on concrete compressive strength of the various aspects related to the use of recycled aggregates (RA) such as replacement level, size, origin, moisture content, exposure of the resulting concrete to different environmental conditions, use of chemical admixtures and additions, and strength development over time The data were collectively subjected to a statistical analysis, the results of which allowed producing a model for predicting concrete strength, based on the quality and content of the RA
214 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 |