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See detailA Parametric Distance Function Approach for Malmquist Productivity Index Estimation
Fuentes, Hugo J.; Grifell-Tatjé, Emili; Perelman, Sergio ULg

in Journal of Productivity Analysis (2001), 15

Malmquist indexes of productivity are generally estimated using index number techniques or non-parametric frontier approaches. The aim of this paper is to showthat Malmquist indexes can be estimated in a ... [more ▼]

Malmquist indexes of productivity are generally estimated using index number techniques or non-parametric frontier approaches. The aim of this paper is to showthat Malmquist indexes can be estimated in a similar way using parametric-deterministic or parametric-stochastic frontier approaches. To allow a multi-output multi-input technology and for technical change in production, we adopt an output distance function which is specified in a translog form. We then show that using the estimated parameters, several radial distance functions can be calculated and combined in order to estimate and decompose the productivity index. Finally, this approach is applied to a panel of Spanish insurance companies. The main results confirm those generally obtained for financial services: very low rates of growth and technical change in spite of a rapid deregulation process and expansion of activity. [less ▲]

Detailed reference viewed: 79 (2 ULg)
See detailParametric numerical study of seismic slope stability and the Newmark method
Havenith, Hans-Balder ULg; Torgoev, Almazbek ULg; Lamair, Laura ULg

Conference (2013, April)

2D dynamic modelling of seismic slope stability is applied to a landslide-prone area in Central Asia, the Mailuu-Suu Valley, situated in the south of Kyrgyzstan. The calculations are made with models ... [more ▼]

2D dynamic modelling of seismic slope stability is applied to a landslide-prone area in Central Asia, the Mailuu-Suu Valley, situated in the south of Kyrgyzstan. The calculations are made with models constructed from over 30 profiles located in the target area, presenting different geological, tectonic and morphological settings. One part of the profiles were selected within landslide zones, the other part was selected in stable areas. Many of the landslides are complex slope failures involving falls, rotational sliding and/or planar sliding and flows. These input data were extracted from a 3D structural geological model built with the GOCAD software. Geophysical and geomechanical parameters were defined on the basis of results obtained by multiple surveys performed in the area over the past 15 years. These include geophysical investigation, seismological experiments and ambient noise measurements. Dynamic modelling of slope stability is performed with the UDEC version 4.01 software that is able to compute deformation of discrete elements. Inside these elements both elasto-plastic and purely elastic materials (similar to rigid blocks) were tested. Various parameter variations were tested to assess their influence on the final outputs. For a few models groundwater flow is included. The total parametric study involved more than 100 different models (about 800 computation hours). Preliminary results allow us to compare Newmark displacements computed using different GIS approaches (Jibson et al., 1998; Miles and Ho, 1999, among others) with the displacements computed using the original Newmark method (Newmark, 1965, here simulated seismograms were used) and displacements produced along joints by the corresponding 2D dynamical models. The generation of seismic amplification and its impact on peak-ground-acceleration, Arias Intensity and permanent slope movements (total and slip on joints) is assessed for numerous morphological-lithological settings (curvature, slope angle, surficial geology, various layer dips and orientations) throughout the target area. The final results of our studies should allow us to define the limitations of the simplified GIS-based Newmark displacement modelling; thus, the verified method would make landslide susceptibility and hazard mapping in seismically active regions more reliable. [less ▲]

Detailed reference viewed: 34 (3 ULg)
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See detailParametric numerical study of seismic slope stability and verification of the Newmark method
Torgoev, Almazbek ULg; Havenith, Hans-Balder ULg

in Ugai, K; Wakai, A; Yagi, H (Eds.) Proceedings of the International Symposium on Earthquake-induced landslides, Kiryu, Japan, 2012 (2012, December)

2D dynamic modelling of seismic slope stability is applied to a landslide-prone area in Central Asia, the Mailuu-Suu Valley, situated in the south of Kyrgyzstan. The calculations are made with models ... [more ▼]

2D dynamic modelling of seismic slope stability is applied to a landslide-prone area in Central Asia, the Mailuu-Suu Valley, situated in the south of Kyrgyzstan. The calculations are made with models constructed from over 30 profiles located in the target area, presenting different geological, tectonic and morphological settings. One part of the profiles were selected within landslide zones, the other part was selected in stable areas. Many of the landslides are complex slope failures involving falls, rotational sliding and/or planar sliding and flows. These input data were extracted from a 3D structural geological model built with the GOCAD software. Geophysical and geomechanical parameters were defined on the basis of results obtained by multiple surveys performed in the area over the past 15 years. These include geophysical investigation, seismological experiments and ambient noise measurements. Dynamic modelling of slope stability is performed with the UDEC version 4.01 software that is able to compute deformation of discrete elements. Inside these elements both elasto-plastic and purely elastic materials (similar to rigid blocks) were tested. Various parameter variations were tested to assess their influence on the final outputs. For a few models groundwater flow is included. The total parametric study involved more than 100 different models (about 800 computation hours). [less ▲]

Detailed reference viewed: 52 (4 ULg)
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See detailParametric Study for the Creation of the Interface between Concrete and Repair Products
Courard, Luc ULg

in Materials and Structures (2000), 33

An analysis as large as possible presents factors acting when a repair system comes into contact with a concrete support. The appetency of the first one for the second is defined from the properties of ... [more ▼]

An analysis as large as possible presents factors acting when a repair system comes into contact with a concrete support. The appetency of the first one for the second is defined from the properties of the support and the new layer – essentially in its liquid phase – as well as from the environmental conditions. These properties are cited or explained for each material: roughness, porosity, superficial cohesion and interstitial water into concrete, nature and concentration of the binder, rigidity modulus, capillary succion for repair systems. The thermodynamic properties of the materials as well as transport mechanisms – diffusion, capillary succion – at the interface and roughness of the concrete support are particularly developed. A sequential flow sheet related to the parameters influencing the creation of the interface is proposed. [less ▲]

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See detailParametric study of ductile moment resisting frames. First step for Eurocode 8 calibration.
Sanchez-Ricart, L.; Plumier, André ULg

in Earthquake Engineering & Structural Dynamics (2008)

A parametric study of 13,608 ductile Moment-Resisting Steel Frames (MRSF) designed according to Eurocode 3 and Eurocode 8 is performed. A flowchart for the evaluation of the seismic-resistant capacity of ... [more ▼]

A parametric study of 13,608 ductile Moment-Resisting Steel Frames (MRSF) designed according to Eurocode 3 and Eurocode 8 is performed. A flowchart for the evaluation of the seismic-resistant capacity of the designed frames is developed based on the N2 method. The design structural overstrength, the ductility supply, the plastic redistribution parameter, the supply reduction factor and the performance ratio of the frames under study are analysed. The 13,608 designed frames under study have performance ratios higher than one mostly due to the high values of design structural overstrength, showing that the seismic supply produced by Eurocode 3 and Eurocode 8 restrains are always higher than the seismic demand. [less ▲]

Detailed reference viewed: 89 (3 ULg)
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See detailParametric study of metal/polymer multilayer coatings for temperature wrinkling prediction
Zhang, Lihong ULg; Habraken, Anne ULg; Ben Bettaieb, Amine ULg et al

in Journal of Materials Engineering & Performance (2013), 22(9), 2437-2445

Detailed reference viewed: 21 (10 ULg)
Peer Reviewed
See detailParametric study of the numerical modelling for semi-rigid joints
Jaspart, Jean-Pierre ULg; Gerardy, J. C.; Maquoi, René ULg

in proceedings of the Annual technical session and meeting of the SSRC (1991)

Detailed reference viewed: 7 (0 ULg)
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See detailA parametric study on the emissions from an HCCI alternative combustion engine resulting from the auto-ignition of primary reference fuels
Machrafi, Hatim ULg; Cavadias, Simeon; Amouroux, Jacques

in Applied Energy (2008), 85(8), 755-764

The homogeneous charge compression ignition is an alternative combustion technology that can reduce automobile pollution, provided that the exhaust emission can be controlled. A parametric study can be ... [more ▼]

The homogeneous charge compression ignition is an alternative combustion technology that can reduce automobile pollution, provided that the exhaust emission can be controlled. A parametric study can be useful in order to gain more understanding in the emission reduction possibilities via this new combustion technology. For this purpose, the inlet temperature, the equivalence ratio and the compression ratio are changed, respectively, from 30 to 70 degrees C, 0.28 to 0.41 and 6 to 14. Also the diluting, thermal and chemical effects of exhaust gas recirculation were studied. The emission of CO, CO2, O-2 and hydrocarbons has been measured using primary reference fuels. It appears that an increase in the inlet temperature, the EGR temperature, the equivalence ratio and the compression ratio results into a decrease of the emissions of CO and the hydrocarbons of up to 75%. The emission of CO2 increased, however, by 50%. The chemical parameters showed more complicated effects, resulting into a decrease or increase of the emissions, depending on whether the overall reactivity increased or not. If the reactivity increased, generally, the emissions of CO and hydrocarbons increased, while that of CO2 increased. The increase of CO2 emissions could be compensated by altering the compression ratio and the EGR parameters, making it possible to control the emission of the HCCI engine. (c) 2008 Elsevier Ltd. All rights reserved. [less ▲]

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See detailParametrical study on the behaviour of steel and composite cellular beams under fire conditions
Vassart, Olivier; Bailey, C. G.; Bihina, Gisèle et al

in Kodur, Venkatesh; Franssen, Jean-Marc (Eds.) Structures in Fire. Proceedings of the Sixth International Conference (2010)

This paper describes an extensive parametric study on the behaviour of cellular beam under fire conditions. Different finite element models using shell elements were developed considering both material ... [more ▼]

This paper describes an extensive parametric study on the behaviour of cellular beam under fire conditions. Different finite element models using shell elements were developed considering both material and geometrical non-linearity; CAST3M [1], ANSYS [2] and another one in SAFIR [3]. They were calibrated on the basis of a new experimental test campaign performed in the scope of the project FICEB+ [4] funded by the Research Fund for Coal and Steel. The comparison between the finite element prediction and actual experimental results showed a good agreement in terms of failure modes, load deflection relationship and ultimate loads. At failure, temperature measured during the fire tests indicated that failure arising by web post buckling of cellular beams in fire cannot be simply estimated by applying temperature dependent reduction factors on strength alone, as given in codes. A design model representing the behaviour of cellular beam in fire conditions has been developed by Vassart [5-7]. This design model is able to predict the complex behaviour of cellular beam in case of fire comprising web-post buckling and Vierendeel bending, as well as standard flexural bending. The results of the Finite Element Models are compared in terms of critical temperatures and failure mode obtained using the design model. This paper also contains some tests results that were used to calibrate the FEM model and the comparison between analytical and FEM models. [less ▲]

Detailed reference viewed: 137 (10 ULg)
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See detailThe Parametrized Diastolic Filling Formalism: Application in the Asklepios Population
Claessens, Tom; Muhammad Waheed, Raja; Pironet, Antoine ULg et al

in Conference Program ASME 2011 Summer Bioengineering Conference (2011, June)

Detailed reference viewed: 35 (7 ULg)
See detailLes paramyxovirus des mammifères marins
Jauniaux, Thierry ULg

in proceeding of the conference (2004)

Detailed reference viewed: 4 (0 ULg)
See detailParana Medio, a multipurpose transport development (Argentina).
Marchal, Jean ULg

Report (1988)

Detailed reference viewed: 16 (0 ULg)
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See detailParapet wall effect on Piano Key Weirs efficiency
Machiels, Olivier; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Journal of Irrigation & Drainage Engineering (2013), 139(6), 506-511

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam projects with a high level of constraints (limited space, high specific flood discharge, small reservoir level ... [more ▼]

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam projects with a high level of constraints (limited space, high specific flood discharge, small reservoir level variation). While the higher efficiency of the Piano Key Weir compared to standard linear weirs has already been demonstrated, its optimal geometry is still poorly defined. In order to improve the design of the complex geometry of this structure, the use of parapet walls has been tested. They consist of vertical extensions placed over the weir crest. Following a former study of the influence of the weir height on its discharge capacity, this paper presents the results of an experimental campaign dedicated to investigating the effect of parapet walls to increase weir height while reducing bottom slopes and keeping the weir height constant. These results indicate the relative influences of the alveoli bottom slopes and of the weir height on the Piano Key Weir release capacity. Comparisons with former experimental results as well as design guidelines are also provided. [less ▲]

Detailed reference viewed: 106 (10 ULg)
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See detailParaplégie traumatique. Mise au point et analyse d'un modèle expérimental.
Martin, Didier ULg; Delrée, P.; Leprince, Pierre ULg et al

Conference (1989, March)

Detailed reference viewed: 18 (3 ULg)
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See detailParapsoriasis en plaques.
HERMANNS-LE THI KIM, Trinh ULg; PIERARD, Gérald ULg

in Thérapeutique Dermatologique (2012)

Detailed reference viewed: 22 (2 ULg)
See detailParasite communities: Patterns and Processes
Rentier, Bernard ULg

in Book Reviews, Biochemical Systematics and Ecology (G. Esch, A. Bush & J. Aho, eds., Chapman & Hall, 1990) (1991)

Detailed reference viewed: 35 (2 ULg)
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See detailA parasite reveals cryptic phylogeographic history of its host.
Nieberding, C.; Morand, S.; Libois, Roland ULg et al

in Proceedings of the Royal Society B : Biological Sciences (2004), 271(1557), 2559-68

This study compares the continental phylogeographic patterns of two wild European species linked by a host-parasite relationship: the field mouse Apodemus sylvaticus and one of its specific parasites, the ... [more ▼]

This study compares the continental phylogeographic patterns of two wild European species linked by a host-parasite relationship: the field mouse Apodemus sylvaticus and one of its specific parasites, the nematode Heligmosomoides polygyrus. A total of 740 base pairs (bp) of the mitochondrial cytochrome b (cyt b) gene were sequenced in 122 specimens of H. polygyrus and compared with 94 cyt b gene sequences (974 bp) previously acquired for A. sylvaticus. The results reveal partial spatial and temporal congruences in the differentiation of both species' lineages: the parasite and its host present three similar genetic and geographical lineages, i.e. Western European, Italian and Sicilian, and both species recolonized northwestern Europe from the Iberian refuge at the end of the Pleistocene. However, H. polygyrus presents three particular differentiation events. The relative rate of molecular evolution of the cyt b gene was estimated to be 1.5-fold higher in the parasite than in its host. Therefore, the use of H. polygyrus as a biological magnifying glass is discussed as this parasite may highlight previously undetected historical events of its host. The results show how incorporating phylogeographic information of an obligate associate can help to better understand the phylogeographic pattern of its host. [less ▲]

Detailed reference viewed: 8 (1 ULg)