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Peer Reviewed
See detailExperimental and numerical study of flange class 3 cross-section members
Boissonnade, N.; Jaspart, Jean-Pierre ULg

in Proceedings of the International Conference on Stability and Ductility of Steel Structures (2006)

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See detailExperimental and numerical study of fracture healing in a murine fracture model
Geris, Liesbet ULg; Gerisch, A.; Maes, C. et al

Poster (2005)

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See detailExperimental and numerical study of TA-6V mechanical behavior in different monotonic loading conditions at room temperature
Gilles, Gaëtan ULg; Cazacu, Oana; Hammami, Walid ULg et al

in Procedia IUTAM (2012), 3

This paper presents an experimental characterization of the quasi-static mechanical response of a TA-6V titanium alloy in sheet form. Monotonic tests, such as uniaxial tension and compression, plane ... [more ▼]

This paper presents an experimental characterization of the quasi-static mechanical response of a TA-6V titanium alloy in sheet form. Monotonic tests, such as uniaxial tension and compression, plane strain and simple shear, were conducted along several orientations in the plane of the sheet in order to investigate the plastic anisotropy and the tension-compression asymmetry displayed by the material at the macroscopic scale. It was observed a moderate anisotropy in yielding while the anisotropy in r-ratios is very pronounced. Initial yielding is described using criteria that account for both plastic anisotropy and strength differential effects. Comparison between experimental data and FE simulation results illustrates the ability of the model to predict the mechanical response of TA-6V. [less ▲]

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See detailExperimental and numerical study of TA6V mechanical behavior under different quasi-static strain paths at room temperature
Gilles, Gaëtan ULg; Habraken, Anne ULg; Cazacu, Oana et al

in AIP Conference Proceedings (2013), 1532

This paper presents an experimental study of the quasi-static mechanical behavior of TA6V titanium alloy. Different monotonic tests were carried out in several orientations in the plane of the sheet in ... [more ▼]

This paper presents an experimental study of the quasi-static mechanical behavior of TA6V titanium alloy. Different monotonic tests were carried out in several orientations in the plane of the sheet in order to characterize the anisotropy and the tension-compression asymmetry exhibited by the material. Initial yielding is modeled by the phenomenological CPB06 criterion and Voce's isotropic hardening is used to describe its evolution. The simulation of a deep-drawing process is performed using the proposed constitutive modeling and compared with experimental data. [less ▲]

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See detailExperimental and numerical study of the breaching of an embankment dam
Dupont, E.; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Proceedings of the 32nd IAHR Biennial Congress - Harmonizing the demands from art and nature (2007)

In the framework of the study of the collapse of an embankment dam following its overtopping, an experimental study of the progressive breaching of such a dam has been performed. The present laboratory ... [more ▼]

In the framework of the study of the collapse of an embankment dam following its overtopping, an experimental study of the progressive breaching of such a dam has been performed. The present laboratory tests enable to validate and to complete a numerical approach previously studied by the authors. The two-dimensional analysis of the breaching is carried out on a scale model in a flume. A cross-section of a dam is scaled according to proper similarity rules, both for the flow and for the solid transport. The originality of the approach lies in the interaction between the experimental and numerical work. The experiments on the scale model are filmed in order to determine the time evolution of the dam profiles. The cross sections are extracted from the films and analyzed by an image-processing algorithm specifically developed for this application. These results are integrated into the hydrodynamic model WOLF2D, which computes the flow generated by the given transient topography and eventually supplies the relevant hydraulic parameters characterizing the dam breaching. [less ▲]

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See detailExperimental and numerical study of the factors influencing the performances of magnetic screens made of high temperature superconductors
Fagnard, Jean-François ULg

Doctoral thesis (2011)

In this thesis, we investigate in details the magnetic shielding processes in high temperature superconductors. We aim at predicting and measuring the influence of the parameters governing the ... [more ▼]

In this thesis, we investigate in details the magnetic shielding processes in high temperature superconductors. We aim at predicting and measuring the influence of the parameters governing the superconducting behaviour (e.g., the critical current density Jc and its field dependence) on the magnetic flux penetration inside hollow cylinders. Three objectives are pursued. The first objective is to characterize the performances of cylindrical magnetic shields made of various high temperature superconductors (Bi-2223, Bi-2212, Y-123) for several external parameters that can be directly controlled in the experiments. These include the temperature, the geometry of the magnetic screen, the amplitude of the applied magnetic field, its orientation (H // or ⊥ cylinder axis) and its frequency (in the case of an AC excitation). The focus has been put on the effect of the sweep rate of the applied magnetic field, dBapp/dt, on the threshold magnetic flux density, Blim, above which the magnetic shielding is no longer efficient. We show that the curve of dBapp/dt vs. Blim can be directly related to the E(J) constitutive law and we explain how the field dependence of the critical current density affects the relationship between both curves. A wide range of electric field levels is investigated in this thesis thanks to the use of a number of experimental techniques. The experimental set-ups required for these investigations are described in a separate chapter where the performances and limitations of each set-up is put forward. The second objective of the thesis is to confront experimental data and numerical simulations using models of increasing complexity. We present two numerical models that take into account the strongly non-linear E(J) relationship characterizing the superconducting behaviour. The first numerical model is based on the Brandt algorithm. This model is able to describe magnetic shielding experiments which involve time-varying magnetic fields on (i) infinite samples subjected to transverse magnetic fields or on (ii) samples of finite size in axisymmetric geometries subjected to axial magnetic fields. The second model is based on a finite element method (using the GetDP software). This model can be used for both axisymmetric 2D modelling and full 3D modelling. In the latter case, it provides extremely useful information for understanding configurations where the applied magnetic field and the hollow cylinder do not present a particular symmetry. Both 2D and 3D models are able to provide current and field distributions in the superconductor. The confrontation between experimental and modelling results allows us to better understand how physical properties (critical temperature Tc, critical current density Jc, ...) and geometry affect the magnetic shielding performances (shielding factor SF, threshold induction Blim). Conversely, we present three different practical procedures using either the analytical Bean model or a 2D numerical model in order to determine the constitutive law parameters of the superconducting materials from data measured on hollow cylinders. As a third objective, we aim at investigating how the different types of HTS magnetic screens of moderate dimensions (a few cubic centimetres) could be scaled up in order to provide larger shielded volumes. Three methods are explored. The first method to build larger magnetic screens (typically ten(s) of centimetres) is to find means to assemble several (pieces of) superconducting hollow cylinders to obtain a large shielding enclosure. Experiments are carried out on superconducting cylinders cut either along or perpendicular to their axis. The influence of the cut width and the angle of the applied magnetic field with respect to the cut plane are studied. Modellings are carried out on shorter cylinders in order to understand how the presence of the cut modifies the current distribution and thus the magnetic shielding properties. The second method consist in characterizing the magnetic shielding of several hollow cylinders made with the same superconducting material but having different sizes. This helps us in determining whether the manufacturing process is able to provide large cylinders with good magnetic shielding performances. In a last method, we investigate an architecture of superconducting magnetic screens that differs from those based on bulk hollow cylinders. The idea is to exploit the high Jc-performances of superconducting tapes (based on thin film technology) to build magnetic shielding structures which can be easily scalable. The measurement results obtained on such structures are promising as the actual limitation seems to be geometrical. Using more superconducting tapes in order to achieve a higher aspect ratio should give magnetic shields which are as efficient as bulk cylinders. [less ▲]

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See detailExperimental and numerical study on mechanoregulation of tissue differentiation around a loaded implant in a bone chamber
Van Oosterwyck; Geris, Liesbet ULg; Duyck, Joke et al

in Bischoff, G.; Hein, H.-J. (Eds.) Proceedings of the seventh conference of ESEM (2003)

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See detailExperimental and simulation study of the Schottky barrier lowering by substrate doping variation for PtSi Source/Drain SBFETs
Lousberg, Grégory ULg; Yu, Hong-Yu; Froment, Benoit et al

in Proceedings of ESSDERC 2006 (2006, September)

In this paper, the authors study experimentally and numerically the Schottky barrier height (SBH) lowering of Pt silicide/n-Si diodes and its implications to Schottky-barrier (SB) source/drain p-FETs. The ... [more ▼]

In this paper, the authors study experimentally and numerically the Schottky barrier height (SBH) lowering of Pt silicide/n-Si diodes and its implications to Schottky-barrier (SB) source/drain p-FETs. The authors demonstrate that hole SBH can be lowered through an image-force mechanism by increasing the n-Si substrate doping, which leads to a substantial gain of the drive current in the long-channel bulk p-SBFETs. Numerical simulations show that the channel doping concentration is also critical for short-channel n- & p-SOI SBFETs performance [less ▲]

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See detailExperimental and Theoretical Energy Levels, Transition probabilities and Radiative Lifetimes in Yb III
Biémont, Emile ULg; Garnir, Henri-Pierre ULg; Li, Z. S. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2001), 34

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See detailExperimental and theoretical investigation of radiative decay rates of metastable levels in LaII
Derkatch, A.; Ilyinsky, L.; Mannervik, S. et al

in Physical Review A (2002), 65(6),

An experimental and theoretical investigation of lifetimes of metastable levels in La II has been performed. The experimentally obtained results using the laser probing of a stored ion beam were tau=5.2 ... [more ▼]

An experimental and theoretical investigation of lifetimes of metastable levels in La II has been performed. The experimentally obtained results using the laser probing of a stored ion beam were tau=5.2+/-0.2 s for the a(1)G(4) and tau=2.1+/-0.3 s for the b(1)D(2) levels. Within the error bars, the results are in good agreement with the relativistic Hartree-Fock calculations including core polarization. [less ▲]

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See detailExperimental and theoretical investigation of the lamellar structure of a styrene-butyl methacrylate diblock copolymer by fluorescence resonance energy transfer, small-angle X-ray scattering, and self-consistent-field simulations
Spiro, John G; Yang, Jiahn; Zhang, Jian-Xin et al

in Macromolecules (2006), 39(20), 7055-7063

We have investigated the repeat distance and interface thickness, at 160 degrees C, of a poly(styrene-b-butyl methacrylate) (PS-b-PBMA) diblock copolymer of similar to 180 000 molecular weight by small ... [more ▼]

We have investigated the repeat distance and interface thickness, at 160 degrees C, of a poly(styrene-b-butyl methacrylate) (PS-b-PBMA) diblock copolymer of similar to 180 000 molecular weight by small- angle X-ray scattering (SAXS) and fluorescence resonance energy transfer ( FRET). We have found a lamellar period of 47 nm and an interface thickness of 5 nm. A simple, hyperbolic secant model of the junction distribution appeared to be sufficient to analyze the fluorescence decay data on the junction-labeled polymer containing different acceptor/donor ratios, but simulations based on a numerical self- consistent-field (NSCF) formalism also allowed us to find a range of approximately 0.017-0.018 for the Flory-Huggins interaction parameter (chi(FH), defined with reference to the monomeric volume of polystyrene) and a PBMA Kuhn length (b(PBMA)) of 0.65-0.67 nm. We note that earlier values of chi(FH) and b(PBMA) reported in the literature vary considerably. The NSCF computations suggest that even modest levels of conformational asymmetry perturb the block copolymer morphology. A weakness of our theoretical (NSCF) approach is the compressible nature of PS-b-PBMA. However, lattice cluster, equation of state (EOS), or other models that allow for compressibility have not yet been developed to the level of sophistication needed to predict block copolymer repeat distances or interface thicknesses. Indeed, as detailed in the Supporting Information, current EOS methods leave much to be desired even in predicting the phase transitions of lower molecular weight PS-b-PBMA samples. [less ▲]

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See detailExperimental and theoretical investigations of the electrical properties of undoped and magnesium-doped GaN layers
Nguyen, Ngoc Duy ULg; Germain, Marianne; Schmeits, Marcel et al

in Journal of Crystal Growth (2001), 230

The ac characteristics of GaN : Mg and undoped GaN layers, grown by MOVPE on sapphire substrates, are measured for a wide range of temperature and bias conditions, in order to investigate the effect of ... [more ▼]

The ac characteristics of GaN : Mg and undoped GaN layers, grown by MOVPE on sapphire substrates, are measured for a wide range of temperature and bias conditions, in order to investigate the effect of the magnesium-related level on the transport properties. Two peaks, whose height and position depend on the measurement temperature, are observed in the admittance curves (G/ω versus frequency) of the Mg-doped samples, whereas only one peak appears in undoped samples. The study of the frequency dependence of the impedance, with a model including the two metallic Au/GaN junctions, the GaN layer itself, shows that, besides the effect of the differential resistance of the layer which plays a role in both sample types, the presence of a Mg-related deep level contributes to the observed variations of the peaks in the admittance curves of the p-doped samples. Results of a theoretical steady-state and small-signal analysis based on numerical modelling of the Au/GaN/Au heterostructure complete our analysis. [less ▲]

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See detailExperimental and theoretical investigations of the electrical properties of undoped and magnesium-doped GaN layers
Nguyen, Ngoc Duy ULg; Germain, Marianne; Schmeits, Marcel et al

Conference (2000)

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See detailExperimental and theoretical lifetimes and transition probabilities in Sb I
Hartman, H; Nilsson, H; Engström, L et al

in Physical Review. A (2010), 82

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See detailExperimental and theoretical lifetimes in Yb III
Zhang, Z. G.; Li, Z. S.; Svanberg, S. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2001), 15

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See detailExperimental and theoretical radiative decay rates for highly excited ruthenium atomic levels and the solar abundance of ruthenium
Fivet, V.; Quinet, Pascal ULg; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2009), 396

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new ... [more ▼]

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new abundance value (in the usual logarithmic scale where the solar hydrogen abundance is equal to 12.00), ARu = 1.72 ± 0.10, is in agreement with the most recent meteoritic result, ARu = 1.76 ± 0.03. The accuracy of the transition probabilities, obtained using a relativistic Hartree–Fock model including core-polarization effects, has been assessed by comparing the theoretical lifetimes with previous experimental results. A comparison is also made with new measurements performed in this work by the time-resolved laser-induced fluorescence spectroscopy for 10 highly excited odd-parity levels of Ru I [less ▲]

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See detailExperimental and theoretical radiative lifetimes, branching fractions, and oscillator strengths for Lu I and experimental lifetimes for Lu II and Lu III
Fedchak, J. A.; Den Hartog, E. A.; Lawler, J. E. et al

in Astrophysical Journal (2000), 542

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See detailExperimental and theoretical radiative properties of odd-parity highly excited levels in Mo II
Jiang, L; Wang, Q; Feng, Y et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2012), 66

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See detailExperimental and theoretical radiative properties of odd-parity highly excited levels in Mo II
Jiang, L; Wang, Q; Feng, Y et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2012), 66

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See detailExperimental and theoretical studies of DyIII: radiative lifetimes and oscillator strengths of astrophysical interest
Zhang, Z. G.; Svanberg, S.; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2002), 334(1), 1-10

The lifetimes of three short-lived levels belonging to the 4f(9) 6p configuration and of two long-lived levels of the 4f(9) 5d configuration of Dy iii have been measured for the first time using time ... [more ▼]

The lifetimes of three short-lived levels belonging to the 4f(9) 6p configuration and of two long-lived levels of the 4f(9) 5d configuration of Dy iii have been measured for the first time using time-resolved laser-induced fluorescence techniques. They are in good agreement with theoretical values calculated within the framework of a pseudo-relativistic configuration interaction approximation. Using the experimental lifetimes and the theoretical branching fractions, a first set of transition probabilities of astrophysical interest has been obtained for Dy III. [less ▲]

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