The University of Namur or Université de Namur, in Namur , is a Jesuit, Catholic public university in the French Community of Belgium. Both teaching and research are carried out in six Faculties or university level schools in the fields of: Philosophy and Lettres Law Economic, Social, and Management science Computer science science Medicine↑ Wikipedia.
Preat J.,University of Namur
Journal of Physical Chemistry C | Year: 2010
We have conducted a theoretical investigation to model the mechanisms of photoinduced electron injection and energy transfer for a recent organic metal-free dye derived from the triphenylamine (2TPA-R) structure. The 2TPA-R system results from the fusion between two TPA moieties connected by a vinyl group, and the rhodanine-3-acetic acid is used as the electron acceptor group. In a first step, DFT and TDDFT approaches have been exploited to calculate the key parameters controlling the intramolecular charge transfer (ICT) injection and ET transfer rate constants in the classical Marcus formalism: (i) the electronic coupling; (ii) the reorganization energies; and (iii) the variation of the Gibbs energy. In a nice agreement with the experimental trends, the results have highlighted that (i) two excited states [EE(1), lower in energy, and EE(2), higher in energy] have been calculated at 2.78 and 3.33 eV; (ii) the energy transfer (ET) between these two excited states is in competition with the electron injection from the EE(2); (iii) when 2TPA-R is excited at 3.33 eV, the ET between the resulting relaxed excited states EE(2) and EE(1) directly takes place, and the probability of injection from EE(2) is weak; (iv) the ET remains governed by the Dexter mechanism. Indeed, the ratio between the Förster and Dexter rate constants (kF/kD) is evaluated at ∼10-4. Second, we propose structural modifications improving the electron injection efficiency of the TPA-based DSSCs, and we show that using the 1-CN,2-COOH-ethylene group as the acceptor unit combined with a functionalization of the TPA moieties by -OMe groups significantly improves the key parameters related to the electron injection. © 2010 American Chemical Society. Source
Rinaldi M.,University of Namur
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
We study the gravitational field equations in the presence of a coupling between the derivative of a massless scalar field and the Einstein tensor. This configuration is motivated by Galileon gravity as it preserves shift invariance in the scalar sector. We analytically obtain solutions with static and spherically symmetric geometry, which also include black holes with a single regular horizon. We examine the thermodynamical properties of these solutions, and we reveal the nonperturbative nature of the coupling constant. We also find a phase transition, similar to the one described by Hawking and Page, which occurs at a critical temperature determined by both the black hole mass and by the strength of the coupling. © 2012 American Physical Society. Source
Deparis O.,University of Namur
Optics Letters | Year: 2011
In spite of the fact that solutions to Maxwell's equations in stratified isotropic optical media are well known, it appears that an explicit expression of the Poynting vector flux spatial evolution inside such a medium has not been derived so far. Based on exact electromagnetic field solutions in the transfer-matrix formalism, I derive such an expression and show that, due to the presence of counterpropagating waves in the medium, an additional contribution to the flux appears that exists only in optically absorbing layers and arises from the interference between these waves. Based on this theory, the concept of incremental absorption is introduced for the calculation of the light absorption profile along the stratification direction. As an illustration of this concept, absorption profiles in a Si-based thin-film tandem solar cell are predicted at typical wavelengths. © 2011 Optical Society of America. Source
Biro L.P.,Institute of Technical Physics and Materials Science |
Lambin P.,University of Namur
New Journal of Physics | Year: 2013
The scientific literature on grain boundaries (GBs) in graphene was reviewed. The review focuses mainly on the experimental findings on graphene grown by chemical vapor deposition (CVD) under a very wide range of experimental conditions (temperature, pressure hydrogen/hydrocarbon ratio, gas flow velocity and substrates). Differences were found in the GBs depending on the origin of graphene: in micro-mechanically cleaved graphene (produced using graphite originating from high-temperature, high-pressure synthesis), rows of non-hexagonal rings separating two perfect graphene crystallites are found more frequently, while in graphene produced by CVD - despite the very wide range of growth conditions used in different laboratories - GBs with more pronounced disorder are more frequent. In connection with the observed disorder, the stability of two-dimensional amorphous carbon is discussed and the growth conditions that may impact on the structure of the GBs are reviewed. The most frequently used methods for the atomic scale characterization of the GB structures, their possibilities and limitations and the alterations of the GBs in CVD graphene during the investigation (e.g. under e-beam irradiation) are discussed. The effects of GB disorder on electric and thermal transport are reviewed and the relatively scarce data available on the chemical properties of the GBs are summarized. GBs are complex enough nanoobjects so that it may be unlikely that two experimentally produced GBs of several microns in length could be completely identical in all of their atomic scale details. Despite this, certain generalized conclusions may be formulated, which may be helpful for experimentalists in interpreting the results and in planning new experiments, leading to a more systematic picture of GBs in CVD graphene. © IOP Publishing and Deutsche Physikalische Gesellschaft. Source
Agency: Cordis | Branch: H2020 | Program: IA | Phase: ICT-20-2015 | Award Amount: 7.28M | Year: 2016
Although online education is a paramount pillar of formal, non-formal and informal learning, institutions may still be reluctant to wager for a fully online educational model. As such, there is still a reliance on face-to-face assessment, since online alternatives do not have the deserved expected social recognition and reliability. Thus, the creation of an e-assessment system that will be able to provide effective proof of student identity, authorship within the integration of selected technologies in current learning activities in a scalable and cost efficient manner would be very advantageous. The TeSLA project provides to educational institutions, an adaptive trust e-assessment system for assuring e-assessment processes in online and blended environments. It will support both continuous and final assessment to improve the trust level across students, teachers and institutions. The system will be developed taking into account quality assurance agencies in education, privacy and ethical issues and educational and technological requirements throughout Europe. It will follow the interoperability standards for integration into different learning environment systems providing a scalable and adaptive solution. The TeSLA system will be developed to reduce the current restrictions of time and physical space in teaching and learning, which opens up new opportunities for learners with physical or mental disabilities as well as respecting social and cultural differences. Given the innovative action of the project, the current gap in e-assessment and the growing number of institutions interested in offering online education, the project will conduct large scale pilots to evaluate and assure the reliability of the TeSLA system. By the nature of the product, dissemination will be performed across schools, higher education institutions and vocational training centres. A free version will be distributed, although a commercial-premium version will be launched on the market.