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See detailA one-field discontinuous Galerkin formulation of non-linear Kirchhoff-Love shells
Noels, Ludovic ULg

in International Journal of Material Forming (2009), 2(Suppl. 1), 877-880

Spatially-discontinuous Galerkin methods constitute a generalization of weak formulations, which allow for discontinuities of the problem unknowns in its domain interior. This is particularly appealing ... [more ▼]

Spatially-discontinuous Galerkin methods constitute a generalization of weak formulations, which allow for discontinuities of the problem unknowns in its domain interior. This is particularly appealing for problems involving high-order derivatives, since discontinuous Galerkin (DG) methods can also be seen as a means of enforcing higher-order continuity requirements. Recently, DG formulations of linear and non-linear Kirchhoff-Love shell theories have been proposed. This new one-field formulations take advantage of the weak enforcement in such a way that the displacements are the only discrete unknowns, while the C1 continuity is enforced weakly. The Resulting one field formulation is a simple and efficient method to model thin structures and can be applied to various computational methods. [less ▲]

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See detailA one-field formulation of elasto-plastic shells with fracture applications
Becker, Gauthier; Noels, Ludovic ULg

Conference (2012, July)

The main feature of Discontinuous Galerkin (DG) methods is their ability to take into account discontinuities of the unknown field in the interior domain of studied problems. In such formulations the ... [more ▼]

The main feature of Discontinuous Galerkin (DG) methods is their ability to take into account discontinuities of the unknown field in the interior domain of studied problems. In such formulations the integration by parts is realized on the elements leading to boundary integral terms These terms between elements ensure the continuity and compatibility of the solution in a stable manner, which makes DG attractive to ensure weakly the C0 continuity and/or the C1 continuity. For non-linear Kirchhoff-Love shells, the C0/DG formulation - the C0 continuity is ensured as usual by considering continuous shape functions and the C1 continuity is weakly ensured by DG interface terms in a stable and consistent way - leads to a one-field formulation, where the displacements are the only unknowns of the problem [5]. DG methods have also an advantage when it comes to simulate fracture with a cohesive approach. Indeed, the classical cohesive methods suffer from severe limitations. The intrinsic approach, which inserts the cohesive elements at the beginning, requires an initial slope in the traction separation law and suffers from lack of consistency, while the extrinsic cohesive method, which inserts the cohesive elements during the simulation when a fracture criterion is reached, suffers from difficult parallel implementation due to the topological mesh modifications happening during the simulations. To overcome these limitations, new methods were developed and in particular, an approach based on a C0-discontinuous Galerkin formulation where continuity between elements is ensured weakly by the interface elements. These interface elements can be easily replaced by a cohesive element during the simulation, leading to an efficient fracture framework [4, 6]. We have recently extended this approach for linear shells [1] to obtain a full DG formulation of thin bodies, where discontinuities in the C0 and C1 fields are weakly enforced using consistent interface elements, and where the interface elements can be used to integrate the cohesive law when a fracture criterion is met. Moreover, a new cohesive law based on the reduced stresses of the thin bodies formulation is developed to propagate a fracture through the thickness. This cohesive model dissipates the right amount of energy during crack initiations and/or propagations. These developments are extended to non-linear elasto-plastic shells and are implemented in parallel, which allows to simulate complex fracture problems. As a validation example, the study of a blasted notched-cylinder is performed, for which experimental and numerical (by XFEM method) data are reported in the literature by [3]. Figure 1 illustrates the results obtained at different times. It can be seen that the simulation allows to model crack propagation, as well as the bifurcation happening when the crack reaches the top of the cylinder. Also, it appears that with the elasto-plastic framework, the crack speed numerically predicted matches the experimental measures [2]. [less ▲]

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See detailOne-loop finite corrections to seesaw neutrino masses
Aristizabal Sierra, Diego ULg

in PoS - Proceedings of Science (2011)

In the standard seesaw model, finite corrections to the neutrino mass matrix arise from one-loop self-energy diagrams mediated by heavy neutrinos. We discuss the impact that these corrections may have on ... [more ▼]

In the standard seesaw model, finite corrections to the neutrino mass matrix arise from one-loop self-energy diagrams mediated by heavy neutrinos. We discuss the impact that these corrections may have on the different entries of the tree-level effective neutrino mass matrix, paying special attention to their dependence with the seesaw model parameters. We also briefly comment on the implications these corrections might have on low-energy neutrino observables. [less ▲]

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See detailA one-nucleotide difference in a cAMP and phorbol ester response element leads to differential regulation of the human chorionic somatomammotropin A and B gene transcription
Oury, Cécile ULg; Alsat, E.; Jacquemin, P. et al

in Journal of Molecular Endocrinology (1997), 18(2), 87-99

Human chorionic somatomammotropin (hCS) is encoded by two highly related genes, hCS-A and hCS-B, located in the hGH/hCS gene locus. Both genes are expressed in the syncytiotrophoblast layer of the ... [more ▼]

Human chorionic somatomammotropin (hCS) is encoded by two highly related genes, hCS-A and hCS-B, located in the hGH/hCS gene locus. Both genes are expressed in the syncytiotrophoblast layer of the placenta and hCS release from trophoblast cells is known to be increased by cAMP and phorbol esters. However, it remains unclear whether this regulation acts at the level of hCS gene expression or secretion and whether both genes are affected. We examined the effects of cAMP and phorbol 12-myristate 13-acetate (PMA) on the transcription of the hCS-A and hCS-B genes. Transient expression experiments revealed a 7 bp cAMP- and PMA-responsive element (CRElhCS-A) spanning nucleotides-1102 to -1096 upstream of the hCS-A gene. In contrast, the homologous sequence upstream of hCS-B (CRElhCS-B), differing from CRElhCS-A by a single substitution, shows little or no response to cAMP. In band-shift assays, the CRElhCS-A oligonucleotide was shown to bind two factors related to CREBP and AP-1, whereas CRElhCS-B only competes for one of these complexes. Finally, Southwestern analysis revealed that the CRElhCS-A element binds two ubiquitous proteins of 100 kDa and 47 kDa respectively, whereas CRElhCS-B interacts only with the 47 kDa protein. Taken together, these results suggest that a 47 kDa protein binding to the CRElhCS-A and CRElhCS-B elements is involved in the PMA response of the hCS-A and hCS-B genes, and a 100 kDa protein plays a crucial role in cAMP regulation of the hCS-A gene. [less ▲]

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See detailA One-Phase Thermomechanical Constitutive Model for the Numerical Simulation of Semi-Solid Thixoforming
Koeune, Roxane ULg; Ponthot, Jean-Philippe ULg

in Proceedings of ESAFORM 2008, Conference on material forming (2008)

A thermo mechanical one-phase elasto-visco-plastic constitutive law has been developed in order to model thixoforming processes. The simulation of a simple academic 2D test has revealed the forces and ... [more ▼]

A thermo mechanical one-phase elasto-visco-plastic constitutive law has been developed in order to model thixoforming processes. The simulation of a simple academic 2D test has revealed the forces and weaknesses of the proposed model. [less ▲]

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See detailA one-phase thermomechanical constitutive model for the numerical simulation of semi-solid thixoforming
Koeune, Roxane ULg; Ponthot, Jean-Philippe ULg

in International Journal of Material Forming (2008), suppl. 1

A thermomechanical one-phase elasto-visco-plastic constitutive law has been developed in order to model thixoforming processes. The simulation of a simple academic 2D test has revealed the forces and ... [more ▼]

A thermomechanical one-phase elasto-visco-plastic constitutive law has been developed in order to model thixoforming processes. The simulation of a simple academic 2D test has revealed the forces and weaknesses of the proposed model. [less ▲]

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See detailA one-phase thermomechanical Model for Semi-Solid thixoforming
Koeune, Roxane ULg; Ponthot, Jean-Philippe ULg

in Solid State Phenomena (2008), 141-143

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See detailOne-photon mazer resonances for arbitrary field modes
Bastin, Thierry ULg; Solano, E.

Poster (1999)

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See detailOne-piece zirconia implants : 18 months clinical outcomes.
VANHOUTTE, Vanessa ULg; LAMBERT, France ULg; ROMPEN, Eric ULg

Conference (2009, December)

Purpose : The aim of the present study was to evaluate prospectively the clinical outcomes of a prototype one-piece zirconia implants after a -18 month follow-up. Material and methods : 20 prototype one ... [more ▼]

Purpose : The aim of the present study was to evaluate prospectively the clinical outcomes of a prototype one-piece zirconia implants after a -18 month follow-up. Material and methods : 20 prototype one-piece zirconia implants were placed and immediately restored with provisional protheses. A flapless or a minimally invasive approach was used for every implant placement. Bone levels were recorded at baseline and -1 year. Surgical, biological and prosthetic complications were also assessed. Results : The study included 15 patients. Most of the implants (90%) were placed at the anterior maxilla. Six of the implant sites were previously augmented with autogenous bone block grafts, 8 were managed with socket preservation techniques, 3 implants were immediatly placed after extraction and one implant was placed simultanously with a guided bone regeneration. Insertion torque (> 30N/cm2) was reached for all implants. The implant survival and success rates reached respectively 100% and 95%. One implant abutment fractured at placement because of an excessive insertion torque (> 50 N/cm2). No further complication occurred. Conclusion : From the preliminary results of this prospective clinical study, one-piece zirconia implants seem to success after 1 year despite they were often placed in critical clinical situtations (bone augmentations) and immediately restored. Further follow-up is needed to evaluate the long-term outcomes. [less ▲]

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See detailOne-pot controlled synthesis of double thermoresponsive N-vinylcaprolactam-based copolymers with tunable LCSTs
Kermagoret, Anthony ULg; Fustin, Charles-André; Bourguignon, Maxime et al

in Polymer Chemistry (2013), 4(8), 2575-2583

N-Vinylcaprolactam (NVCL) was copolymerized statistically for the first time in a controlled manner with hydrophilic N-vinylamide or hydrophobic vinylester monomers in order to precisely tune up and down ... [more ▼]

N-Vinylcaprolactam (NVCL) was copolymerized statistically for the first time in a controlled manner with hydrophilic N-vinylamide or hydrophobic vinylester monomers in order to precisely tune up and down the lower critical solution temperature (LCST) of the resulting copolymers. The incorporation of these segments in complex architectures was also considered. Several narrowly distributed NVCL-based copolymers were prepared by cobalt-mediated radical polymerization (CMRP) using the bis-(acetylacetonato)cobalt(II) complex as a controlling agent and N-methyl-N-vinylacetamide (NMVA), N-vinylacetamide (NVA), vinyl acetate (VAc) or vinyl pivalate (VPi) as comonomers. PNVCL-containing block copolymers having two discrete LCSTs were also synthesized following a one-pot strategy based on the sequential CMRP of NVCL followed by the copolymerization of NMVA with the residual NVCL. Upon gradual heating of aqueous solutions of such double thermoresponsive copolymers, we noticed a transition from free chains to micelles before full dehydration and collapse of the block copolymers. These advances represent a significant step towards the development of a platform based on thermoresponsive PNVCL copolymers with a single phase separation or multistep assembly behaviors. [less ▲]

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See detailOne-pot enzymatic synthesis of the Gal alpha 1-->3Gal beta 1-->4GlcNAc sequence with in situ UDP-Gal regeneration.
Hokke, Cornelis H; Zervosen, Astrid ULg; Elling, Lothar et al

in Glycoconjugate Journal (1996), 13(4), 687-92

The trisaccharide Gal alpha 1-->3Gal beta 1-->4GlcNAc beta 1-->O-(CH2)8COOCH3 was enzymatically synthesized, with in situ UDP-Gal regeneration. By combination in one pot of only four enzymes, namely ... [more ▼]

The trisaccharide Gal alpha 1-->3Gal beta 1-->4GlcNAc beta 1-->O-(CH2)8COOCH3 was enzymatically synthesized, with in situ UDP-Gal regeneration. By combination in one pot of only four enzymes, namely, sucrose synthase, UDP-Glc 4'-epimerase, UDP-Gal:GlcNAc beta 4-galactosyltransferase and UDP-Gal:Gal beta 1-->4GlcNAc alpha 3-galactosyltransferase, Gal alpha 1-->3Gal beta 1-->4GlcNAc beta 1-->O-(CH2)8COOCH3 was formed in a 2.2 mumol ml-1 yield starting from the acceptor GlcNAc beta 1-->O-(CH2)8COOCH3. This is an efficient and convenient method for the synthesis of the Gal alpha 1-->3Gal beta 1-->4GlcNAc epitope which pays an important role in various biological and immunological processes. [less ▲]

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See detailOne-pot process for the preparation of functionalized alkoxyamines
Detrembleur, Christophe ULg; Gross, Thomas; Meyer, Rolf-Volker

Patent (2004)

The present invention relates to a new one-pot process for the preparation of functionalized alkoxyamine initiators of the formula (I) <CHEM> from amines of the formula (II) <CHEM> and to a process of ... [more ▼]

The present invention relates to a new one-pot process for the preparation of functionalized alkoxyamine initiators of the formula (I) <CHEM> from amines of the formula (II) <CHEM> and to a process of controlled radical polymerization using the functionalized alkoxyamine as initiators. In the above formulae, R<1>-R<5> have the meanings given in the description. [less ▲]

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See detailOne-pot surfactant assisted synthesis of aluminosilicate macrochannels with tunable micro- or mesoporous wall structure
Léonard, Alexandre ULg; Blin, J.-L.; Su, B.-L.

in Chemical Communications (2003), 9(20), 2568-2569

A one-step surfactant assisted synthesis pathway was developed leading to novel hierarchical macro-meso- (or micro-)porous aluminosilicates made of an assembly of macrochannels with openings between 0.5 ... [more ▼]

A one-step surfactant assisted synthesis pathway was developed leading to novel hierarchical macro-meso- (or micro-)porous aluminosilicates made of an assembly of macrochannels with openings between 0.5 and 2.0 μm and wormhole-like amorphous walls with tunable pore sizes. [less ▲]

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See detail“One-pot” dispersion ATRP and alkyne-azide Huisgen’s 1,3-dipolar cycloaddition in supercritical carbon dioxide: towards the formation of functional microspheres
Grignard, Bruno ULg; Calberg, Cédric ULg; Jérôme, Christine ULg et al

in Journal of Supercritical Fluids (2010), 53(1-3), 151-155

Functional polymers were successfully prepared in scCO2 by combining alkyne-azide 1,3-dipolar Huisgen’s cycloaddition and dispersion ATRP in a “one pot” process using new perfluorinated polymeric amino ... [more ▼]

Functional polymers were successfully prepared in scCO2 by combining alkyne-azide 1,3-dipolar Huisgen’s cycloaddition and dispersion ATRP in a “one pot” process using new perfluorinated polymeric amino-based ligands that had a dual role, i.e. the complexation of the copper catalyst and the stabilization of growing particles. [less ▲]

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See detailOne-Step Gem-Diphosphorylation of Amides and Lactams
Olive, Gilles ULg; Le Moigne, François; Mercier, Anne et al

in Synthetic Communications (2000), 30(4), 619-627

We report the extension of an easy one-step synthesis of amino gem-bisphosphonates through the reaction of amides and lactams with trialkykphosphites

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See detailOne-step polymer grafting from silicon nitride SPM probes: From isolated chains to brush regime
Gabriel, Sabine ULg; Jérôme, Christine ULg; Jérôme, Robert ULg et al

in Journal of the American Chemical Society (2007), 129(27), 8410

We show that a reactive polymer can be directly grafted from commercial Si3Nx SPM tips, without any intermediate layer. The conditions can be chosen to achieve either an isolated mushroom regime, with ... [more ▼]

We show that a reactive polymer can be directly grafted from commercial Si3Nx SPM tips, without any intermediate layer. The conditions can be chosen to achieve either an isolated mushroom regime, with only one or a few chains accessible at the tip apex, or a brush regime. [less ▲]

Detailed reference viewed: 64 (13 ULg)