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See detailLocal ionospheric activity – nowcast and forecast services
Stankov, Stanimir; Warnant, René ULg; Stegen, Koen et al

Conference (2009)

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See detailLocal ionospheric electron density profile reconstruction in real time from simultaneous ground-based GNSS and ionosonde measurements
Stankov, Stanimir; Stegen, Koen; Muhtarov, Plamen et al

in Advances in Space Research (2011), 47(7), 1172-1180

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See detailLocal Knowledge in Policy Making
Schoenaers, Frédéric ULg; Delvaux, Bernard

in Policy and Society (2012), 31(2), 106-169

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See detailLocal mapping of dissipative vortex motion
Silhanek, Alejandro ULg

Conference (2013, May)

We have recently introduced an experimental technique which combines the spatial resolution of scanning Hall microscopy and sensitivity of ac-susceptibility measurements as a tool to probe the vortex ... [more ▼]

We have recently introduced an experimental technique which combines the spatial resolution of scanning Hall microscopy and sensitivity of ac-susceptibility measurements as a tool to probe the vortex dynamics in superconducting materials. This technique has proven to be particularly adequate to prospect the degree of mobility of each individual vortex, map the pinning landscape, visualize the intra-valley to inter-valley vortex hopping, and reveal the different mobility of vortices and antivortices created by magnetic dots. Furthermore, we have shown that using the phase sensitive character of the local ac-susceptibility technique it is possible to investigate the dissipative response of a single vortex. This technique opens new and exciting possibilities to locally study loss mechanisms in a variety of interesting magnetic systems such as magnetic domain walls. [less ▲]

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See detailLocal mapping of dissipative vortex motion
Raes, B; Van de Vondel, J; Silhanek, Alejandro ULg et al

in Physical Review. B : Condensed Matter (2012), 86

We explore, with unprecedented single vortex resolution, the dissipation and motion of vortices in a superconducting ribbon under the influence of an external alternating magnetic field. This is achieved ... [more ▼]

We explore, with unprecedented single vortex resolution, the dissipation and motion of vortices in a superconducting ribbon under the influence of an external alternating magnetic field. This is achieved by combining the phase sensitive character of ac susceptibility, allowing us to distinguish between the inductive and dissipative responses, with the local power of scanning Hall probe microscopy. Whereas the induced reversible screening currents contribute only inductively, the vortices do leave a fingerprint in the out-of-phase component. The observed large phase-lag demonstrates the dissipation of vortices at time scales comparable to the period of the driving force (i.e., 13 ms). These results indicate the presence of slow microscopic loss mechanisms mediated by thermally activated hopping transport of vortices between metastable states. [less ▲]

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See detailLocal measurement system for optical and electro-optic characterization and homogeneity analysis of photorefractive sillenite crystals
Lemaire, Philippe ULg; Georges, Marc ULg

in Roosen, G.; Agullo-Lopez, F.; Schirmer, O. (Eds.) Proceedings of Symposium C on Photorefractive Materials of the 1994 E-MRS Spring Conference (1994, May)

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See detailLocal measurements of void fraction and liquid holdup in packed columns using X-ray computed tomography
Toye, Dominique ULg; Marchot, Pierre ULg; Crine, Michel ULg et al

in Chemical Engineering & Processing (1998), 37(6), 511-520

A 'tailor made' computed X-ray tomographic scanner has been developed as a tool for the analysis of the distribution of gas, liquid and solid phases in packed columns. The very good spatial resolution of ... [more ▼]

A 'tailor made' computed X-ray tomographic scanner has been developed as a tool for the analysis of the distribution of gas, liquid and solid phases in packed columns. The very good spatial resolution of the scanner has first been assessed by the imaging of objects of known shape and size, called 'physical' phantoms. Images have then been realized on a 0.6 m diameter and 2 m height column packed with Cascade Mini-Ring 1A packing elements, which is a random polypropylene packing designed to be used in absorption columns. The solid phase distribution, leading to the void fraction distribution, has been analyzed on cross-section images of the dry packed column (without any liquid flowrate). The measured value of the bed void fraction is equal to the value provided by the manufacturer. The analysis of the axial profile of void fraction shows that the 'end effect' may be neglected, whereas the analysis of the radial profile evidences the existence of a non negligible 'wall effect'. Images have then been carried out on the packed column irrigated by a liquid flowrate ranging between 0 and 6000 1 h(-1) (0-6.10(-3) m s(-1)). Hold-up values have been measured in different cross-sections of the column and averaged in order to obtain the total hold-up value in the bed. The computed values are in very good agreement with those reported in the literature for similar packing. The dependence of the liquid hold-up on the liquid superficial velocity can be expressed in terms of a power law. The fitted value of the exponent, equal to 0.65, is in the range of exponent values found in correlations of the literature. (C) 1998 Elsevier Science S.A. All rights reserved. [less ▲]

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See detailLocal Mechanical Stimuli Regulate Bone Formation and Resorption in Mice at the Tissue Level
Schulte, Friederike A.; Ruffoni, Davide ULg; Lambers, Floor M. et al

in PLOS ONE (2013), 8(4), 62172-12

Bone is able to react to changing mechanical demands by adapting its internal microstructure through bone forming and resorbing cells. This process is called bone modeling and remodeling. It is evident ... [more ▼]

Bone is able to react to changing mechanical demands by adapting its internal microstructure through bone forming and resorbing cells. This process is called bone modeling and remodeling. It is evident that changes in mechanical demands at the organ level must be interpreted at the tissue level where bone (re) modeling takes place. Although assumed for a long time, the relationship between the locations of bone formation and resorption and the local mechanical environment is still under debate. The lack of suitable imaging modalities for measuring bone formation and resorption in vivo has made it difficult to assess the mechanoregulation of bone three-dimensionally by experiment. Using in vivo micro-computed tomography and high resolution finite element analysis in living mice, we show that bone formation most likely occurs at sites of high local mechanical strain (p<0.0001) and resorption at sites of low local mechanical strain (p<0.0001). Furthermore, the probability of bone resorption decreases exponentially with increasing mechanical stimulus (R-2 = 0.99) whereas the probability of bone formation follows an exponential growth function to a maximum value (R-2 = 0.99). Moreover, resorption is more strictly controlled than formation in loaded animals, and ovariectomy increases the amount of non-targeted resorption. Our experimental assessment of mechanoregulation at the tissue level does not show any evidence of a lazy zone and suggests that around 80% of all (re) modeling can be linked to the mechanical microenvironment. These findings disclose how mechanical stimuli at the tissue level contribute to the regulation of bone adaptation at the organ level. [less ▲]

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See detailLocal Operational Geomagnetic Index K Calculation (K-LOGIC) from digital ground-based magnetic measurements
Stankov, Stanimir; Stegen, Koen; Warnant, René ULg

Report (2011)

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See detailLocal order of the high-pressure metallic phase of liquid selenium: a diffraction study
Raty, Jean-Yves ULg; Gaspard, Jean-Pierre ULg; Le Bihan, T. et al

in Journal of Physics : Condensed Matter (1999), 11(50), 10243-1024910249

Liquid selenium undergoes a phase transition towards a metallic phase when sufficient pressure is applied. We performed an x-ray diffraction experiment at the 1D30 beamline of the ESRF at the wavelength ... [more ▼]

Liquid selenium undergoes a phase transition towards a metallic phase when sufficient pressure is applied. We performed an x-ray diffraction experiment at the 1D30 beamline of the ESRF at the wavelength of 0.149 Aring to investigate the local order of the metallic liquid. The diffraction pattern of liquid Se has been recorded with the large-volume Paris-Edinburgh cell between (20degC, 3 GPa) and (1650degC, 4.1 GPa). The local order of the metallic liquid selenium is found to be close to that of liquid tellurium. In particular, the coordination number Z increases with temperature from 2.6 to 3.0 [less ▲]

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See detailLocal order, dynamics and stability of C and N doped phase change materials
Hippert, Françoise; Raty, Jean-Yves ULg; Noé, Pierre et al

Conference (2013, July 26)

Doping Chalcogenide Phase Change Materials, such as Ge2Sb2Te5 and GeTe used in non-volatile phase change memories, was shown to improve the stability of the amorphous phase and to strongly increase the ... [more ▼]

Doping Chalcogenide Phase Change Materials, such as Ge2Sb2Te5 and GeTe used in non-volatile phase change memories, was shown to improve the stability of the amorphous phase and to strongly increase the crystallization temperature. We combined total X-ray scattering experiments [1], Fourier Transform InfraRed (FTIR) spectroscopy and ab initio Molecular Dynamics simulations to address the stabilization of the amorphous phase of GeTe doped with Carbon or Nitrogen. The comparison between the simulation and exp erimental results allows in depth understanding of the role of dopants. They deeply modify the structure of the amorphous phase by introducing tetrahedral units centered on C or N, triangular environments and short C chains in C-doped GeTe, N-Ge3 pyramids and N2 molecules in N-doped GeTe. One major difference between N and C doping is the fact that C can form short bonds with Te, although in smaller proportion than C-Ge, while short N-Te bonds are absent in N-doped GeTe. The inclusion of C or N leads to an increase in high frequency vibrational modes, to a reduction of the density of floppy vibrational modes that drive the crystallization and to an increase of the rigidity. This stabilization mechanism could apply more generally to various GST materials as well as to other iono-covalent glasses. [1] G.E. Ghezzi, J.Y.Raty, S. Maitrejean, A. Roule, E. Elkaim and F. Hippert, Appl. Phys. Lett. 99 (2011) 151906 [less ▲]

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See detailLocal ordering and magnetism in Ga0.9Fe3.1N
Burghaus, Jens; Sougrati, Moulay T.; Moechel, Anne et al

in Journal of Solid State Chemistry (2011), 184(9), 2315-2321

Prior investigations of the ternary nitride series Ga1-xFe3+xN (0 <= x 1) have indicated a transition from ferromagnetic gamma'-Fe4N to antiferromagnetic ``GaFe3N''. The ternary nitride ``GaFe3N'' has ... [more ▼]

Prior investigations of the ternary nitride series Ga1-xFe3+xN (0 <= x 1) have indicated a transition from ferromagnetic gamma'-Fe4N to antiferromagnetic ``GaFe3N''. The ternary nitride ``GaFe3N'' has been magnetically and spectroscopically reinvestigated in order to explore the weakening of the ferromagnetic interactions through the gradual incorporation of gallium into gamma'-Fe4N. A hysteretic loop at RI reveals the presence of a minority phase of only 0.1-0.2 at\%, in accord with the sound two-step synthesis. The composition of the gallium-richest phase ``GaFe3N'' was clarified by Prompt Gamma-ray Activation Analysis and leads to the berthollide formula Ga0.91(1)Fe3.09(10)N1.05(7). Magnetic measurements indicate a transition around 8 K, further supported by Mossbauer spectral data. The weakening of the ferromagnetic coupling through an increasing gallium concentration is explained by a simple Stoner argument. In Ga0.9Fe3.1N the presence of iron on the gallium site affects the magnetism by the formation of 13-atom iron clusters. (C) 2011 Elsevier Inc. All rights reserved. [less ▲]

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See detailLocal orders in II-VI liquid compounds
Gaspard, Jean-Pierre ULg; Raty, Jean-Yves ULg; Ceolin, R. et al

in Journal of Non-Crystalline Solids (1996), 205-207

The structure of liquid CdTe, HgTe and ZnTe is studied by neutron scattering. Upon melting, drastically different behaviors are found: CdTe and ZnTe keep their fourfold coordination in the melt and remain ... [more ▼]

The structure of liquid CdTe, HgTe and ZnTe is studied by neutron scattering. Upon melting, drastically different behaviors are found: CdTe and ZnTe keep their fourfold coordination in the melt and remain semiconductors, whereas HgTe becomes sixfold coordinated and metallic. This dissimilarity is discussed in terms of the electronegativity difference and of the repulsive potential hardness. Entropic aspects are also discussed [less ▲]

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See detailLocal perceptions and attitudes towards synanthrope long-tailed macaques (Macaca fascicularis) living in Padangtegal Monkey forest, Bali (Indonesia)
Brotcorne, Fany ULg; Paquay, Leila; Wandia, I.Nengah et al

Conference (2013, October 03)

The sympatric relationship between humans and other primates in interface zones is a contemporary widespread phenomenon. The expanding landscapes anthropization leads to an intensification of human-other ... [more ▼]

The sympatric relationship between humans and other primates in interface zones is a contemporary widespread phenomenon. The expanding landscapes anthropization leads to an intensification of human-other primate interactions ranging from conflict to co-operation scenarios. Our study investigated the commensal relationships between long-tailed macaques and humans at the tourist Padangtegal Monkey Forest. We present here results related to human-macaque interactions and local people’s perceptions and attitudes towards the latter. We used ethological methods to quantify the nature of the interactions and we conducted a questionnaire survey to identify the macaques’ status in local public opinion. 99 respondents (62 males and 37 females) were selected in a radius of 2km around the Monkey Forest. Perceptions and attitudes were explicitly measured on self-reports and were attributed to a 4 point score. Macaques interacted with humans for 1.1% of their activity budget and these interactions were mostly aggressive (0.6%), food-related (0.4%) or neutral (0.1%). 80% of the aggressive interactions were initiated by humans but the majority aimed at protecting crops and properties from macaques’ incursions. Overall, most of the respondents had positive perceptions and attitudes towards macaques, except neighbouring landowner farmers who suffered from crop damage. Despite nuisances caused by macaques, the majority of the interviewees reported to derive compensatory economic and cultural benefits from their relationships with macaques. The religious and economic contexts might explain the high tolerance level towards macaques that represents a source of hope for a sustainable coexistence, although some management strategies minimizing crop damage still need to be reinforced. [less ▲]

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See detailA local potent glucocorticosteroid decreases the induction of galactosylhydroxylysyl glucosyltransferase in suction blisters but has no effect on basement membrane structures.
Oikarinen, A.; Peltonen, L.; Hintikka, J. et al

in British Journal of Dermatology (1983), 108(2), 171-8

The effects of local glucocorticosteroid treatment on collagen biosynthesis and basement membrane components were studied in suction blisters in human abdominal skin. Pretreatment with clobetasol-17 ... [more ▼]

The effects of local glucocorticosteroid treatment on collagen biosynthesis and basement membrane components were studied in suction blisters in human abdominal skin. Pretreatment with clobetasol-17-propionate, applied three times a day for 4 days, did not affect the activity of galactosylhydroxylysyl glucosyltransferase (GGT) in fresh blisters but post-blistering treatment for 3 days with the steroid markedly inhibited the increase of this enzyme activity during the initial phases of re-epithelialization. The GGT activity was over 50% lower in steroid-treated blisters compared with control values. Protein concentrations and blister fluid volumes were also significantly decreased in healing 3-day blisters after steroid treatment. These results suggest that local glucocorticosteroid decreases either the synthesis of GGT or its release from the tissue into the blister fluid. The treatment did not affect the blister histology nor the early process of re-epithelialization. Immunohistochemically, type IV and V collagens and laminin of the basement membrane zone were similarly located in blisters of steroid-treated and placebo-treated skin, suggesting that local glucocorticosteroid does not affect the integrity of the basement membrane. [less ▲]

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See detailLocal probing of the vortex-antivortex dynamics in superconductor/ferromagnet hybrid structures
Silhanek, Alejandro ULg; Gladilin, V. N.; Van de Vondel, J. et al

in Superconductor Science and Technology (2011), 24(2),

In-plane ferromagnetic bars, densely packed in a linear array underneath a superconducting bridge, create two types of vortex chains of opposite polarity inside the superconductor. In this work we ... [more ▼]

In-plane ferromagnetic bars, densely packed in a linear array underneath a superconducting bridge, create two types of vortex chains of opposite polarity inside the superconductor. In this work we investigate both experimentally and theoretically the dynamics of these vortex chains as a function of an external magnetic field for two different arrangements of magnetic moments, namely parallel and antiparallel. The theoretical approach, based on the time-dependent Ginzburg-Landau formalism, confirms previously proposed empirical models implemented to describe the basic properties of these hybrid systems. In addition, local transport measurements allow us to probe the dynamics of individual vortex channels as a function of the applied magnetic field. These measurements evidence a drastic reduction of the dissipation in the channel populated with vortices having opposite polarity to the applied field. [less ▲]

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See detailLocal search heuristics for large-scale discrete structural optimization with expensive black-box evaluations
Bay, Maud ULg; Crama, Yves ULg; Rigo, Philippe ULg

Report (2009)

This paper considers large-scale structural optimization problems featuring discrete variables, as well as nonlinear implicit constraints which can only be evaluated through time-expensive computations. A ... [more ▼]

This paper considers large-scale structural optimization problems featuring discrete variables, as well as nonlinear implicit constraints which can only be evaluated through time-expensive computations. A prominent application consists in the preliminary structural design of large ships, where many of the variables take their values in discrete sets which model standard element dimensions to be selected from catalogs, and where the evaluation of the constraints involves a complex structural analysis performed by black-box software. The resulting large-scale nonlinear combinatorial problems are particularly hard, and even nding a discrete feasible solution may prove challenging for some instances. In this paper, we propose two heuristics that combine local search methods and a sequential optimization method based on approximations of the implicit constraints. The heuristics are applied to the structural optimization of several large ships. For these instances, the heuristics provide discrete feasible solutions whose value is close to the optimal value of the continuous relaxation obtained by disregarding the discrete nature of the variables. [less ▲]

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See detailLocal Second Gradient Models and Damage Mechanics: 1D Post-Localization Studies in Concrete Specimens
Kotronis, Panagiotis; Collin, Frédéric ULg; Bésuelle, Pierre et al

in Exadaktylos, G.; Vardoulakis, Ioannis (Eds.) Bifurcations, Instabilities, Degradation in Geomechanics (2007)

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See detailLocal second gradient models and damage mechanics: application to concrete
Kotronis, Panagiotis; Chambon, René; Mazars, Jacky et al

Conference (2005)

The non linear behaviour of concrete is often simulated using local constitutive models based on the continuous damage mechanics theory. This approach however is not adequate for post-localisation studies ... [more ▼]

The non linear behaviour of concrete is often simulated using local constitutive models based on the continuous damage mechanics theory. This approach however is not adequate for post-localisation studies with strain softening. It is well known that spurious mesh dependence appears in computations and cases of failure without energy dissipation. In order to improve computational performance second grade local models are chosen to include a meso scale in the continuous damage model. This approach differs from the nonlocal one in the sense that it is a local theory with higher order stresses depending only on the local cinematic history. 1D numerical computations with concrete specimens are presented. Using a random initialisation of the iterative solver of the equilibrium equation we search the existence of various solutions for the boundary value study and also to see if the second grade term regularise the problem giving results that are mesh insensitive and objective. [less ▲]

Detailed reference viewed: 54 (3 ULg)