41,837 research outputs found
Mechanism of oxidation of (olefin)Rh-I and -Ir-I complexes by H2O2
No full textItem does not contain fulltextA DFT study of the oxidation of (tpa)M-I(C2H4)(+) and (dpa-R)M-I(cod)(+) complexes (M = Rh, Ir) by H2O2 indicates that the reaction starts with heterolytic cleavage of the peroxide O-O bond, leading to M-III(olefin)(OH)(2+) species. These can then undergo cyclisation, followed by deprotonation to oxetanes. In the oxidation of COD complexes, further cyclisation to internal ethers has a modest barrier, and the observed products (ethers for Rh, oxetanes for Ir) are suggested to be the thermodynamic ones. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004
Josine H. Blok & André P. M. H. Lardinois (Ed.), Solon of Athens. New Historical and Philological Approaches, 2006
No full textDuplouy Alain. Josine H. Blok & André P. M. H. Lardinois (Ed.), Solon of Athens. New Historical and Philological Approaches, 2006. In: L'antiquité classique, Tome 77, 2008. pp. 622-623
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
A. P. M. H. Lardinois, J. H. Blok & M. G. M. Van der Poel (Ed.), Sacred Words : Orality, Literacy and Religion, 2011
No full textDelli Pizzi Aurian. A. P. M. H. Lardinois, J. H. Blok & M. G. M. Van der Poel (Ed.), Sacred Words : Orality, Literacy and Religion, 2011. In: L'antiquité classique, Tome 82, 2013. pp. 397-399
A. P. M. H. Lardinois, J. H. Blok & M. G. M. Van der Poel (Ed.), Sacred Words : Orality, Literacy and Religion, 2011
No full textDelli Pizzi Aurian. A. P. M. H. Lardinois, J. H. Blok & M. G. M. Van der Poel (Ed.), Sacred Words : Orality, Literacy and Religion, 2011. In: L'antiquité classique, Tome 82, 2013. pp. 397-399
On natural representations of the symplectic group
No full textLet be the Weyl module of dimension for the group arising from the -th fundamental weight of the Lie algebra of . Thus, affords the grassmann embedding of the -th symplectic polar grassmannian of the building associated to . When and is sufficiently large compared with the difference , the -module is reducible. In this paper we are mainly interested in the first appearance of reducibility for a given . It is known that, for given and , there exists an integer such that is reducible if and only if . Moreover, let and the largest proper non-trivial submodule of . Then if while if . In this paper we will show how this result can be obtained by an investigation of a certain chain of -submodules of the exterior power , where $V = V(2n,\mathbb{F})
Josine H. Blok. The Early Amazons. Modem and Ancient Perspectives on a Persistent Myth.
No full textSomville Pierre. Josine H. Blok. The Early Amazons. Modem and Ancient Perspectives on a Persistent Myth. . In: L'antiquité classique, Tome 65, 1996. p. 396
Josine H. Blok. The Early Amazons. Modem and Ancient Perspectives on a Persistent Myth.
No full textSomville Pierre. Josine H. Blok. The Early Amazons. Modem and Ancient Perspectives on a Persistent Myth. . In: L'antiquité classique, Tome 65, 1996. p. 396
3D printed composites - Benchmarking the state-of-the-art
No full textFused filament fabrication (FFF) is a 3D printing technique which allows layer-by-layer build-up of a part by the deposition of thermoplastic material through a nozzle. The technique allows for complex shapes to be made with a degree of design freedom unachievable with traditional manufacturing methods. However, the mechanical properties of the thermoplastic materials used are low compared to common engineering materials. In this work, improved 3D printing feedstocks for FFF, with carbon fibres embedded in a thermoplastic matrix to reinforce the material, are investigated. The state-of-the-art in composite 3D printing is reviewed and the capabilities of two different commercially available composite printing methods are assessed by print trials, optical microscopy and mechanical characterization of the printed materials. It is found that printing of continuous carbon fibres using the MarkOne gives significant increases in performance over unreinforced thermoplastics, with mechanical properties in the same order of magnitude of typical unidirectional epoxy matrix composites. The method, however, is limited in design freedom as the brittle continuous carbon fibres cannot be deposited freely through small steering radii and sharp angles. Filaments with embedded carbon microfibres (∼;100 μm) show better print capabilities and are suitable with standard printing methods, but only offer a slight increase in mechanical properties over the pure thermoplastic properties
Efficient p-Multigrid Based Solvers for Isogeometric Analysis on Multipatch Geometries
No full textIsogeometric Analysis can be considered as the natural extension of the Finite Element Method (FEM) to higher-order spline based discretizations simplifying the treatment of complex geometries with curved boundaries. Finding a solution of the resulting linear systems of equations efficiently remains, however, a challenging task. Recently, p-multigrid methods have been considered [18], in which a multigrid hierarchy is constructed based on different approximation orders p instead of mesh widths h as it would be the case in classical h-multigrid schemes [8]. The use of an Incomplete LU-factorization as a smoother within the p-multigrid method has shown to lead to convergence rates independent of both h and p for single patch geometries [19]. In this paper, the focus lies on the application of the aforementioned p-multigrid method on multipatch geometries having a C0-continuous coupling between the patches. The use of ILUT as a smoother within p-multigrid methods leads to convergence rates that are essentially independent of h and p, but depend mildly on the number of patches.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Numerical Analysi
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