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Lisbon, Portugal

Universidade Nova de Lisboa ˈnɔvɐ dɨ liʒˈboɐ]) or NOVA is a Portuguese public university established in 1973, in Lisbon and is the youngest of the three public universities of Lisbon. NOVA is a higher education institution with internationally recognized research and quality teaching that ensures high levels of professional success to its students.In 2014, the THE-QS World University Rankings has evaluated NOVA as one of the world's best universities being ranked number 312 in the world. Wikipedia.

Pina F.,New University of Lisbon
Journal of Agricultural and Food Chemistry | Year: 2014

Independently of the natural or synthetic origin, flavylium derivatives follow the same network of chemical reactions. Actually, the flavylium cation is stable only at low pH values. Increasing the pH gives rise to the formation of several species: quinoidal bases, hemiketal, cis- and trans-chalcones, and their deprotonated forms. A deep knowledge of the thermodynamics and kinetics of these species is an essential tool to practical applications of these compounds, in particular, in the domain of food chemistry. In this work the network of chemical reactions involving flavylium derivatives is presented, and the respective thermodynamics and kinetics are discussed in detail, including the mathematical expressions and a step-by-step procedure to calculate all of the rate and equilibrium constants of the system. Examples of systems possessing a high or low cis-trans isomerization barrier are shown. Recent practical applications of anthocyanins and related compounds illustrate the potentialities of the flavylium-based family of compounds. © 2014 American Chemical Society.

Carlos Lima J.,New University of Lisbon | Rodriguez L.,University of Barcelona
Chemical Society Reviews | Year: 2011

Gold(i) alkynyl complexes present a growing research field with respect to their very wide range of applications in different areas such as luminescence, molecular recognition, optical switches, electronics and catalysis. Biological applications are also being developed in the recent years, where these complexes are used as therapeutic agents against different illnesses such as cancer cells or malaria. Related to luminescence, a general overview of the different states responsible for the observed emission is also included in this critical review. In some cases, the assignment is complicated due to the influence of the gold(i) atom and its capability to form metal⋯metal interactions (aurophilicity). Although an extensive discussion has been found in the literature related to the luminescent properties of these complexes, to the best of our knowledge there are not reports covering the span of their very interesting applications. The widespread research fields where this kind of complexes could present a key role is presented in this review (119 references). © 2011 The Royal Society of Chemistry.

Scheven U.M.,New University of Lisbon
Physical Review Letters | Year: 2013

We show that transverse dispersion in flow through randomly packed monodisperse spheres (sphere diameter d) is a velocity-dependent superposition of three separable random processes - diffusion with coefficient Dr, intrinsic mechanical dispersion with dispersivity lm=d/33 caused by advection on streamlines, and a newly identified coupled mechanical dispersion with dispersivity lc=d/11, which arises by coupled advection and transverse diffusion at the pore scale. The velocity dependence of the transverse dispersivity is derived from first principles. Our analysis is insensitive to details of the pore geometry and is verified by pulsed field gradient NMR experiments which covered 4.5 orders of magnitude in reduced velocity. © 2013 American Physical Society.

de Almeida J.A.,New University of Lisbon
Earth-Science Reviews | Year: 2010

The construction of a reservoir model begins with the geology, specifically a geological conceptual model, sub-division into layers, top and bottom limits/surfaces, and characterization of rock types or facies within the layers. To model the geology in heterogeneous case studies, of which carbonate reservoirs are a good example, conceptual and deterministic models are unable to adequately represent the internal geometry and, for this reason, stochastic models are most, particularly used mainly for the spatial characterization of rock types.This paper presents a comparison of bi-point geostatistical simulation methods for characterization of lithoclasses, making use of a carbonated reservoir as a case study. To cope with the geological complexity, and to assist in understanding the internal distribution of properties, the lithoclasses were derived from cores based on their lithology, petrophysical properties and capillary pressure, and subsequently extended to log data.Five simulation methodologies, able to deal with categorical variables, are compared in a multi-phase framework: (1) truncated gaussian simulation, posterior conditioning and classification of simulated probabilities based on local and global proportions (TGSPC); (2) truncated gaussian simulation, posterior conditioning and classification using simulated annealing (TGSPC. +. SA); (3) sequential indicator simulation with correction for local probabilities (SIS); (4) simulated annealing post-processing of sequential indicator simulation images (SIS. +. SA); and (5) probability field simulation (PFS). Matched to experimental data, theoretical multi-phase variogram models, and proportions are observed, as well as the presence of artefacts. To evaluate the range of uncertainty of the simulated images, 30 realizations are generated, and entropy and average geobody volumes (connected blocks belonging to the same lithoclass) are computed and compared. © 2010 Elsevier B.V.

Lobo L.S.,New University of Lisbon
Applied Catalysis B: Environmental | Year: 2014

There is good evidence that understanding the kinetics of catalytic carbon gasification involves the use of Fick's Law at nano-level, to evaluate the relative rates of the three main steps: (1) carbon dissolution; (2) carbon bulk diffusion through the catalyst and (3) surface reaction. Intrinsic kinetics should be handled taking that into account. When we observe linearity in the weight vs. time dependence up to more than 50% conversion this is a strong indication that a carbon bulk diffusion mechanism is operating. The peculiar behavior of moving catalyst nanoparticles observed under in-situ microscopy is also explained by the same mechanism. Occurrence of synergetic effects with alloys may be due to facilitating one or more of the three steps. © 2013 The Author.

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